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Volume 40 No 7 NOVEMBER 2013
Journal of the Australian Water Association
INSIDE THIS ISSUE: • Pipes & Pipeline Maintenance • Asset Management • Water Sanitation & Health • Biosolids & Source Management • Project Management PLUS
> Special Update: waterAUSTRALIA’s new direction with AWA
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Contents regular features From the AWA President
National Credentials – To Have Or Not To Have? Graham Dooley
From the AWA Chief Executive
Recognising The Value Of Water For Our Economic Future Jonathan McKeown
water journal MANAGING EDITOR – Anne Lawton Tel: 02 9467 8434 Email: firstname.lastname@example.org TECHNICAL EDITOR – Chris Davis Email: email@example.com
My Point of View
Multiple Stressors In A Changing World Dr Jenny Stauber
Postcard From Indonesia
Dr Dewi Kirono & Grace Tjandraatmadja
Young Water Professionals
CREATIVE DIRECTOR – Mike Wallace Email: firstname.lastname@example.org ADVERTISING SALES MANAGER – Kirsti Couper Tel: 02 9467 8408 (Mob) 0417 441 821 Email: email@example.com NATIONAL MANAGER – PUBLISHING – Wayne Castle Email: firstname.lastname@example.org CHIEF EXECUTIVE OFFICER – Jonathan McKeown
5 Tips For Getting Ahead In The Corporate World Jo Greene
New Products and Services
EXECUTIVE ASSISTANT – Despina Hasapis Email: email@example.com EDITORIAL BOARD Frank R Bishop (Chair); Dr Bruce Anderson, Planreal Australasia; Dr Terry Anderson, Consultant SEWL; Dr Andrew Bath, Water Corporation; Michael Chapman, GHD; Wilf Finn, Norton Rose Fulbright; Robert Ford, Central Highlands Water (rtd); Ted Gardner (rtd); Antony Gibson, Orica Watercare; Dr Lionel Ho, AWQC, SA Water; Dr Brian Labza, Dept Health WA; Dr Robbert van Oorschot, GHD; John Poon, CH2M Hill; David Power, BECA Consultants; Dr Ashok Sharma, CSIRO. PUBLISH DATES Water Journal is published eight times per year: February, April, May, June, August, September, November and December. Please email firstname.lastname@example.org for a copy of our 2013 Editorial Calendar. EDITORIAL SUBMISSIONS Acceptance of editorial submissions is at the discretion of the Editors and Editorial Board.
Tsunami storm barrier in Tsugaru, Japan – an example of managing a high-consequence/low-likelihood risk category.
• Technical Papers & Technical Features: Chris Davis, Technical Editor, email: email@example.com AND firstname.lastname@example.org
special update WaterAUSTRALIA: What Does The Future Hold?
AWA Refocuses The Activities Of WaterAUSTRALIA
volume 40 no 7
Asset Management: It’s Not That Hard Ask For Help And Keep It Simple Matt Gulliver
Monitoring Corrosion Of Assets At ETP
Development Of A Corrosion Management Manual Ulf Kreher, Ike Solomon, David Solomon & Robert Callant
Opportunistic Assessment Of Buried Pipelines
Information For A Water Utility’s Maintenance & Minor Works Program Alf Grigg & Geoff Hales 42
Enterprise Risk Management In Asset-Intensive Organisations Findings Of A Recent Global Survey by KPMG Mark Gibbs & Mike Stoke
Control System Modelling For Perth’s Second Desal Plant
The Value Of Control System Modelling From Early Design Onwards Eelko Van Der Vaart & Faris Hernich
cover The 500km pipeline bringing potable water to the goldfields, running alongside the Great Eastern Highway in Western Australia.
Technical Paper Submission Guidelines Technical Papers should be 3,000–4,000 words long and accompanied by relevant graphics, tables and images. For more detailed submission guidelines please email: email@example.com • General Feature Articles, Industry News, Opinion Pieces & Media Releases: Anne Lawton, Managing Editor, email: firstname.lastname@example.org General Feature Submission Guidelines General Features should be 1,500–2,000 words and accompanied by relevant graphics, tables and images. For more details please email: email@example.com • Water Business & Product News: Kirsti Couper, Advertising Sales Manager, email: firstname.lastname@example.org ADVERTISING Advertisements are included as an information service to readers and are reviewed before publication to ensure relevance to the water sector and the objectives of AWA. PUBLISHER Australian Water Association (AWA) Publishing, Level 6, 655 Pacific Hwy, PO Box 222, St Leonards NSW 1590; Tel: +61 2 9436 0055 or 1300 361 426, Fax: +61 2 9436 0155, Email: email@example.com, Web: www.awa.asn.au COPYRIGHT Water Journal is subject to copyright and may not be reproduced in any format without the written permission of AWA. Email: firstname.lastname@example.org DISCLAIMER Australian Water Association assumes no responsibility for opinions or statements of fact expressed by contributors or advertisers.
NOVEMBER 2013 water
From the President
National Credentials – To Have or Not to Have? Graham Dooley – AWA President
water November 2013
In addition to being President of AWA, I am a Member of two other industry associations: the Australian Institute of Company Directors (AICD) and Engineers Australia (EA). In both cases I am a Fellow. It means a great deal to me that I have been judged by my peers, under rigorous selection criteria, as being worthy of such status and recognition. Both bodies require me to undertake continuous professional development, which I do.
of the level achieved in that employer’s program
Those with whom I do business can see at a glance that I have been assessed to have the experience, the qualifications and the ongoing professional development commitment to be able to reach and maintain the level of Fellow; indeed, I was recently audited by one body.
individual and corporate. Whatever we do, and
If I was a plumber, an electrician, a doctor, an architect, a lawyer, an accountant, an airline pilot, or a member of many other professions, I would have a credential that would signify me as having a particular level of standing in that profession, as well as recognition in a specific area of skill. Some credentials are granted by Government bodies while others, such as my two, are granted by industry associations.
on the other. There are many useful models
The water industry has been grappling with this topic of training, training standards, transportable recognition and credentials for more than a decade, but I believe that as an industry we need to have one uniform, national set of recognisable credentials that all employers and employees find useful and beneficial. Larger employers, such as water utilities, often introduce their own training programs, which is good – however, recognition
and levels of skill in our industry, and I’d recommend
is often not transportable outside that particular location or state. The Board of AWA has been discussing the establishment of a credential system for the water industry for a couple of years, and we are hoping to frame a proposal to discuss with our Branches and corporate stakeholders in 2014. I hope that such an initiative will be well received by members, both however we do it, it needs to work for both groups. My view, which I am discussing with the Board, is that we need a multi-level system of credentials that differentiates between knowledge and experience on the one hand, and skill or speciality that have been embraced by other professional groups. Some work better than others and some are easier to understand. Once established, they need to be properly maintained. In my view, both AICD and EA do this pretty well, at least for me. Our credentials system needs to have some clearly understood delineators between all the types we start thinking about how we might do this. It will come at a cost (modest, I hope), but the career differentiation for those that have the credentials needed to do a job ought to be worth it. It has certainly been worth the extra cost that I have paid in my membership fees over my 40 years as a Professional Engineer and Company Director!
From the CEO
recognising the value of water in shaping our economic future Jonathan McKeown – AWA Chief Executive
We all acknowledge water as a vital ingredient for life, a fact that elevates it to the highest priority of environmental concern. But water is also arguably the single biggest driver for economic prosperity in Australia. The food and beverage industry, agribusiness, power and energy, mining, and tourism and leisure all depend on water and its proper management to succeed. These business sectors will help shape Australia’s future role in Asia and have the combined potential to produce an unparalleled economic boom for Australia. This will, of course, depend on how we manage our water resources to develop these industries, create employment and expand regional communities to supply the growing Asian markets. But it will also depend on a shift in public perception. Before water can become the economic driver it has the potential to be, the Australian community needs to see it in a different context and appreciate its true value. To achieve our goals we need a convergence of several key development factors: • Strong and visionary Federal Governments prepared to support major national priorities in port and rail infrastructure, new regional land and industry development, and globally competitive investment, taxation and labour regulations; • Clear public perceptions about the role and value of water as a driver for economic prosperity; • Continued innovation and practical research, driven by industry for industry; and • Carefully monitored development assessments that balance the proven science relating to water management practices and the economic
potential of new industries to capitalise on Australia’s unique combination of resources and regional opportunities. All of this requires a highly skilled water sector workforce that can best be maintained by a continuous professional development program managed and delivered by the industry – something that AWA is currently analysing. The coal seam gas industry offers a clear example of the importance of getting these development factors considered and understood by all. There will be numerous other industry opportunities offering economic benefits that will also deserve thorough consideration. At the core of these considerations will be Australia’s use of its water resources and the potential effects on these resources. The newly elected Federal Government has expressed intent to convert the opportunities of the ‘Asian Century’ into actual economic prosperity for Australia. AWA welcomes this intent and will help position water as a top policy priority. Throughout November, we will conduct briefings in each state to our corporate members to ascertain their priority issues and share strategic thoughts on building a stronger water sector. We will also meet with the State Ministers responsible for the water portfolio, and the Federal Government, to discuss key issues. As an industry we need to highlight the role of water in the country’s future prosperity. This means engaging with the media, local communities, business colleagues and Parliamentary leaders to remind them that water goes way beyond environmental concerns and is a direct and vital link to Australia’s economic development.
November 2013 water
My Point of View
multiple stressors iN a CHaNgiNg world: impliCatioNs for aQuatiC eCosYstem risK assessmeNt Dr Jenny Stauber, Deputy Chief, CSIRO Land and Water Dr Jenny Stauber has over 30 yearsâ€™ research experience in the fields of aquatic ecotoxicology and human toxicology, and has written over 300 scientific and technical publications relating to the bioavailability and toxicity of contaminants in aquatic systems. Jenny has served on several World Health Organisation review boards and is a member of the working group currently revising the Australian and New Zealand Water Quality Guidelines. Human activities are increasingly altering the composition and integrity of our aquatic, terrestrial and urban ecosystems. Land use changes, altered water availability and quality, increasing urbanisation, population growth and climate change are already having a major impact on habitats, ecological processes and communities, as well as the liveability of our cities. Indeed, â€œliving in a changing environmentâ€? has recently been identified as one of the five strategic national research priorities for Australia. Globally, we have had limited success in considering multiple environmental stressors and how direct and indirect stressors interact and impact on aquatic and terrestrial ecosystems. This will be even more complex when climate variability is taken into account. While global climate change is increasingly accepted within scientific and regulatory communities and by the informed public, to date our understanding of climate change and how it may interact with other environmental stressors, such as contaminants, has been limited. Pulse
water November 2013
releases of contaminants in wastewaters and stormwaters, together with diffuse sources, will be even more important in extreme events such as cyclones and floods. Water utilities, among other industries and regulators, need to better understand the implication of future changes in climate, land use and urbanisation on the risks of chemicals in waterways to ecosystem and human health so that, where necessary, we can begin to implement adaptation and mitigation strategies.
NEW RISK ASSESSMENT METHODS NEEDED The uncertainty and variability of climate drivers poses major challenges for the prediction of effects and implementation of environmental management programs. Contaminant-climate change interactions may occur on vastly different spatial and temporal scales compared to other local stressors. Changes in the types and quantities of chemicals used and possibly released in runoff waters, their transport, fate and accumulation in the environment, and their effects on biota, all need to be considered in risk assessments that incorporate the effects of multiple stressors including climate change. In order to do this effectively, existing risk assessment methods need to change to include consideration of interactive effects on ecosystem services, changing baselines, greater uncertainties and adaptive management. Processes associated with climate change, such as global warming, changes in precipitation, ocean
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My Point of View circulation changes, and increased extreme events, will potentially interact synergistically, additively or antagonistically with chemical stressors to cause both acute and chronic effects on aquatic and terrestrial biota. For example, increased temperature could cause thermal stress and influence food availability and, hence, growth, while salinity changes could exacerbate contaminant effects on biota, leading to reductions in larval survival and development.
for all potential interactions between environmental variables affected by climate change and contaminants of concern, it will be necessary to develop predictive approaches, incorporating mechanistic data into the risk assessment process. Because there is considerable uncertainty associated with predicting these risks and with identifying appropriate management actions, an adaptive management approach will be essential.
These stressors can interact in two ways: indirect stressors, e.g. climate change, can increase or decrease the toxicity of contaminants to biota, or the contaminants themselves can alter the ability of organisms to respond to climate change stressors. This can ultimately lead to ecological thresholds or tipping points, i.e. abrupt changes in community structure or function in response to relatively small perturbations. Populations living at the edge of their physiological tolerance range may be more vulnerable to the effects of these indirect stressors, particularly if the timing of the exposure to a contaminant coincides with a sensitive life stage, such as spawning.
The complex interactions between potential climate change stressors and contaminants make the prediction of impacts on aquatic and terrestrial ecosystems problematic. While some species may be especially vulnerable to climate change per se, impacts will be exacerbated by other ecosystem stressors, notably chemical contaminants, pathogens, invasive species, over-harvesting and habitat destruction.
Historically, ecological risk assessment (ERA) frameworks were developed to examine risks from particular stressors (usually chemical), acting on particular receptors within small geographic boundaries and largely ignored other non-contaminant stressors (physical and biological). Traditionally, ERAs evaluated whether there was a change in ecosystem services (benefits of nature to households, communities, and economies) relative to a reference site or condition. However, under a variable climate, baseline conditions will change over time making it difficult to establish reference conditions that are also changing over time. Endpoints for assessing some components of ecosystem services and models at the regional scale have only recently been developed and have not been examined under conditions of multiple stressors â€“ e.g. the cumulative effects of climate change-induced wetland degradation on water quality. National management frameworks for environmental regulation of contaminants are now incorporating global climate change into the conceptual models that underpin their assessment framework.
DEVELOPING A PREDICTIVE APPROACH Because ecological conditions will change unpredictably with global climate change, simplistic assumptions of static conditions and unidirectional change will no longer apply. Global climate change brings with it the need to consider both contaminant and non-contaminant stressors, which may lead to either negative or positive impacts. Since it is impractical to collect empirical data
water November 2013
More data at multiple levels of organisation are required to understand and predict the effects of climate change: at the organism level on physiology, toxicity and genetics; at the population level on reproduction, dispersal and recruitment; at the community level on species interactions and habitat; and at the ecosystem level on global processes, e.g. biogeochemical cycles. Both modelling and monitoring approaches will be required to address this knowledge gap. Contaminant effects could be of greater consequence under climate change in the case of synergistic interactions, and this will require more stringent environmental quality standards for chemical contaminants in that particular environment. From an ecological restoration perspective, removing one stressor may result in greater benefit than expected in the case of a synergistic interaction, or less than expected in the case of antagonistic interactions. It has been suggested that one immediate management action should be to monitor baseline contaminant concentrations in soils, water and sediments, and to reduce local exposure to contaminants (one stressor) where possible, as this may be more easily tackled initially than removing indirect stressors due to climate change. However, in cases where there are antagonistic interactions between stressors, local interventions may lead to ineffective, costly management actions and wasted management effort. Careful assessment is required on a case-by-case basis. The water industry has a role to support this science and to influence policy development. Clearly, greater effort is required to understand multiple stressors and how to manage them in the broader context of earth systems science as we move forward into a period of likely change.
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WATERAUSTRALIA: WHAT DOES THE FUTURE HOLD? The Australian Water Association refocuses the activities of waterAUSTRALIA The activities of waterAUSTRALIA, which was established in 2009 as a wholly-owned subsidiary of the Australian Water Association, have now been integrated into AWA’s enterprises. This has been done to better align AWA’s staff resources to assist in the delivery of waterAUSTRALIA initiatives. For the last four years waterAUSTRALIA has been working to promote and develop new business for the Australian water industry both domestically and in international markets. It has pursued its goals with the Department of Industry, Commonwealth Government’s Water Supplier Advocate, Austrade (Australian Trade Commission) and other agencies to help organisations in the industry achieve sales growth by bridging new business relationships and to, in turn, drive fresh economic opportunity for Australia’s water sector. To ensure that waterAUSTRALIA can better deliver its offerings, and for AWA to provide added value to AWA membership, the Boards of both waterAUSTRALIA and AWA made the decision to integrate the operations. AWA’s CEO, Jonathan McKeown, has assumed the role of Managing Director of waterAustralia since the end of September, and a transition plan has been developed to ensure that the programs being delivered will be enhanced and more widely promoted. This significant collaboration is a step forward that will ensure an increase in staff support to provide a variety of skills including marketing, event management and advocacy support to assist waterAUSTRALIA in delivering its initiatives.
Getting niche – what’s next for Capability Teams? waterAUSTRALIA has developed five Capability Teams tailored to specific expertise across the industry: Enabling Platforms/ Technologies; Environmental Services; Irrigation; Mains Water and Water Recovery; and Reuse & Treatment. These teams are a starting point for small and medium-sized enterprises (SMEs) to be matched to products or services sought by the international market – exposure SMEs may not have received otherwise. AWA will focus on the growth and types of activities and outcomes offered to the teams – part of a 12-month plan being developed that will see Capability Teams undergo a series of targeted training sessions covering innovation, expanding market reach and increasing sales. The capability teams will be provided with specially tailored assistance to prepare them for new markets and will be encouraged to participate in AWA trade delegations to Asia and Europe in 2014.
water November 2013
If you are interested in joining a Capability Team please email email@example.com
Going the distance Over the next 12 months, waterAUSTRALIA’s operations will place a strong emphasis on identifying international business opportunities, facilitating export growth, and amplifying local supplier brands to the international market. To set these gears in motion, waterAUSTRALIA will be working more collaboratively with Austrade and the Department of Industry to run missions internationally. The objective of each mission will be to present the Australian water industry to overseas markets and provide top-level business introductions with the potential to cultivate business leads.
We wish to thank previous waterAUSTRALIA CEO Les Targ for his strategic direction over the last four years. Les will still be involved with waterAUSTRALIA managing the Suppliers Access to Major Projects (SAMP) program that focuses on opportunities in the US market.
The integration of waterAUSTRALIA into AWA will see strengthened marketing, event management and advocacy support to assist waterAUSTRALIA in delivering its mission.
December 2013 Mission to China waterAUSTRALIA, Austrade and the Department of Industry are inviting Australian water technology and solution providers to join the Australian Water Solutions Mission to China. This mission, led by Australia’s Water Supply Advocate, Bob Herbert, AM, will help introduce delegates to new business in the industrial provinces of Jiangsu and Guangdong. This mission will also showcase the first Australian pavilion at Water Expo + Water Membrane China 2013 (WEC 2013) held in Beijing from 2–4 December. To find out more please email firstname.lastname@example.org
June 2014 Mission to Singapore AWA and waterAUSTRALIA will be leading the Australian delegation to Singapore International Water Week in Singapore in June next year. The trade mission will provide delegates with opportunities to present their expertise and products to one of the world’s largest and most influential water trade exhibitions. Using AWA’s alliance with the Singapore Water Association and its long-established links with the Public Utilities Board of Singapore (PUB), delegates will be offered targeted business matching. Company profiles will be prepared and pre-departure briefings will ensure that delegates are well prepared for SIWW and the new opportunities that will be presented. In addition to SIWW, AWA and waterAUSTRALIA will provide options for delegates to travel to neighbouring markets for specially tailored business meetings. Please email info@ wateraustralia.org for more information.
September 2014 Mission to Europe Later in the year AWA will facilitate an Australian Pavilion at the IWA World Congress & Exhibition in Lisbon, Portugal during September 2014. This event provides Australian companies with the opportunity
to present their own capabilities to one of the largest gatherings of water organisations and professionals in the world. AWA’s exhibition stand will be badged under the waterAUSTRALIA brand. Delegates will be offered tailored business matching both at the Congress in Lisbon and in a range of surrounding European markets. If you are interested in building business links in Europe this is an opportunity that should not be missed. To register your interest please email email@example.com
Supplier Access to Major Projects (SAMP) program The SAMP program, funded by the Department of Industry, is continuing to help collaborate with project developers to identify supply opportunities for capable and competitive Australian companies. The Program is currently securing the most appropriate market access arrangements for each participant company, which involves identifying key market opportunities, establishing relevant US channel partners and engaging the necessary connections. Already we are seeing companies that were part of the first year’s intake displaying an increase in sales. There has been interest in possible targeted missions to the US, and the US representative, Ken Rubin, will potentially deliver this in March/April next year. More information will be available soon. Further, procurement opportunities in the US will continue to be posted on the Industry Capability Network (ICN) Gateway web portal, with all opportunities listed identified as specifically suited to Australian organisations. The main purpose of these listings is to alert Australian suppliers to the range and scope of opportunities in the US market.
November 2013 water
International Would you like to escape the rat race and become a field worker? Médecins Sans Frontières Australia is currently looking for water/ sanitation engineers to work as field workers on overseas assignments. To learn more, please visit www.msf.org.au/join-our-team
National In its preview release of Positioning for Prosperity? Deloitte focuses on where Australia will find its next waves of economic growth, taking a dive into our current wave – mining – and the five new fronts: agribusiness, gas, international education, tourism and wealth management. Water and wastewater is the next growth industry, which will be reported on in 2014.
With severe rainfall deficiencies across large parts of Queensland, New South Wales and the Northern Territory, a return to drought conditions is a reality facing many Australian farmers, prompting a call by the National Farmers’ Federation (NFF) for the Federal Government and the states to finalise details of national drought policy. “The new Federal Government essentially inherited the drought policy of the former Government – which is light on detail, won’t come in for another nine months and provides little comfort for farmers in the grips of yet another drought,” NFF Vice President and Chair of the Drought Working Group, Brent Finlay, said. Mr Finlay’s comments came as Agriculture Minister, Barnaby Joyce, prepared to visit drought-affected farmers in Queensland.
The Murray-Darling Basin Authority (MDBA) has invited comment on a draft strategy that proposes what work needs to be done over the coming years on river constraints in the Murray-Darling Basin. River constraints can be physical structures, or river management rules and practices that we’re now finding limit how effectively we deliver environmental water. MDBA Executive Director, Jody Swirepik, said the strategy required under the Basin Plan was the first step in a larger body of complex work that would take some years to complete.
NWC has outlined its priorities for the next three years in its Strategic Plan 2013–16. The strategic plan will guide the development of a work program that delivers results relevant to improved water decisions and of value to the Commission’s many stakeholders.
The Australian Standards FT-020 Water Microbiology committee has submitted the following draft methods for public comment and ballot: DR AS 4276.14 (Rev). Water Microbiology – Detection of Salmonella spp. (ISO 19250:2010, MOD); DR AS 4276.15 (Rev). Water Microbiology – Examination for Vibrio cholera; DR AS 4276.19 (Rev). Water Microbiology – Examination for thermophilic Campylobacter spp. – Membrane Filtration. Draft methods can be viewed at the Standard Australia website: www.standards.org.au Select the Draft Standards open for Public Comment section and to submit a comment, click on the ‘To Comment’ tab and search for ‘Microbiology’. Public Comment and Ballot closing date is 15/11/2013.
WATER NOVEMBER 2013
The Bureau of Meteorology has published its second Australian Water Resources Assessment. This report will assist all Australians, particularly policy makers and planners, to understand the current state of the nation’s water resources and enable identification of existing and future water management challenges.
Federal Environment Minister Greg Hunt has said he has considered the application of the water trigger to 50 large coal mine and coal seam gas developments currently being assessed under national environment law, and after a careful examination has determined that 47 of the 50 transitional projects will require federal environmental assessment of their impacts on water resources.
New South Wales The New South Wales Irrigators’ Council has released a position paper that outlines the moves it says are necessary to ensure balance between mining, CSG and irrigation. Council Chief Executive Officer, Andrew Gregson, says that they have been working at the detail level with industry and government for two years with significant gains being made, but that the time has come to set the bar on the big issues.
The NSW Government ban on new coal seam gas (CSG) drilling in and around residential areas does not provide enough protection for rural communities, according to green groups and farmers. The NSW Planning Minister, Brad Hazzard, announced that NSW plans to introduce the “toughest CSG controls in Australia” by extending the 2km buffer around residential zones to future growth areas in 56 council areas across NSW. Seven rural residential areas that meet specific village criteria will also be covered by the proposed ban.
The New South Wales Opposition recently obtained figures showing that Sydney Water has slashed about 15 per cent of its staff since the Government took office. After recent budget estimates, the opposition’s water spokesman Walt Secord asked the Finance Minister to provide details about how many positions had been abolished, made redundant or outsourced since April 2011. A total of 459 Sydney Water jobs were cut in that time with nearly half of them in maintenance and general delivery. The Finance Minister Andrew Constance has defended the cuts, saying they are helping to keep down prices for Sydney Water customers.
Thousands of Sydney residents will reduce their use of drinkingquality water by using recycled stormwater for their toilets and laundries, plus enjoy cheaper bills following an agreement between the City of Sydney and a private water utility. Green Square Water, wholly owned by Flow Systems Pty Ltd, will use stormwater at 20 sites to service 7,000 residents and 8,500 workers in the fast-growing Green Square neighbourhood
The NSW Government is seeking input to the dam safety review. The review is being conducted in three stages. The first stage was the KPMG review, the second is a community consultation stage and the third stage is implementation. This consultation process marks commencement of stage two of the review.
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CrossCurrent Sydney Water has won the Customer Service Institute of Australia’s premier award for customer service excellence. Sydney Water was recognised in the government-owned organisation category at an event in Melbourne. Minister for Finance and Services Andrew Constance congratulated Sydney Water on winning the award, which was presented by Michael Pratt, the Customer Service Commissioner for NSW, and accepted on behalf of Sydney Water by Manager of Customer Interaction, Kathy Hourigan. Sydney Water also received a Highly Commended in the Large Business Category.
Victoria The future health of Victoria’s rivers, estuaries and wetlands has received a boost with the Victorian Coalition Government launching an eightyear strategy to improve the environmental management of waterways. Minister for Water, Peter Walsh, released the Victorian Waterway Management Strategy and also launched an Instagram competition to encourage greater public connection with Victoria’s waterways.
Victorian Minister for Water, Peter Walsh, has switched on pumps to trial a project that will store hundreds of millions of litres of high quality recycled water in deep underground aquifers in Werribee. The Aquifer Storage and Recovery project will store excess water produced from the soon to be completed recycled water facility at the Werribee Treatment Plant.
The final stage of a $6.7 million pipeline that will see new industrial and residential estates in Melbourne’s South East receive Class A recycled water for non-drinking uses is in progress. The 8.5 kilometre pipeline will connect the Logis industrial estate and Meridian residential estate with Class A recycled water supplied by the Eastern Treatment Plant in Bangholme.
South Australia An organisational restructure for SA Water is underway to ensure it continues to respond to customer expectations and to meet the challenges of the emerging water industry in South Australia. SA Water Chief Executive John Ringham says driving greater efficiencies across the business and improving end-to-end customer service delivery has guided SA Water’s current organisational change.
Australian Capital Territory Canberra’s water utility has appealed the June water price determination that will reduce household water and sewerage bills by about $83 a year. The Independent Competition and Regulatory Commission increased water prices 5 per cent this financial year and cut sewerage charges 18 per cent. ACTEW has applied for a review of the ruling and warns, in an application to the ICRC, that it is seeking higher prices to address its concerns.
Northern Territory The Northern Territory Government has approved the next stage in the reform of the Territory’s utilities market. From July next year the Power and Water Corporation will be restructured to separate its monopoly and competitive businesses into stand-alone governmentowned corporations with separate boards.
Federal Agriculture Minister Barnaby Joyce says the Top End can increase its irrigated farming output without having to dam more tropical rivers. He says the Territory can create more irrigated croplands, with the expansion of the Ord River project from Western Australia into the Northern Territory and using water from the aquifers in the Katherine region, about 300 kilometres south of Darwin. The minister told ABC local radio in Darwin that the focus would likely be more on aquifers, rather than damming rivers such as the Daly and the Roper.
Tasmania A state-of-the-art wastewater treatment system planned for Davis station will convert effluent into some of the cleanest water in the world which, when it’s discharged to the ocean, will have minimal impact on the marine environment. The two-year research project has been awarded and funded by the Australian Water Recycling Centre of Excellence. The treatment plant is being built at the Australian Antarctic Division in Hobart, with funding, research, design and testing input from university and industry partners, including Victoria University, the University of Melbourne, Veolia Water and AECOM.
Western Australia The Goyder Institute has released the report on The Status of Water Sensitive Urban Design Schemes in South Australia. You can download the report at www.goyderinstitute.org
The State Government has introduced a motion in both houses of the South Australian Parliament condemning Queensland’s lack of consultation over proposals likely to affect the quality and quantity of water flowing into the Lake Eyre Basin. Queensland has flagged changing the Cooper Creek and Georgina and Diamantina Wild Rivers declarations, which could have serious implications for the Basin’s environmental health.
WATER NOVEMBER 2013
Water Minister Terry Redman fears some commercial water users are deliberately wasting millions of litres of supplies to hang on to their licences. Amid efforts to overhaul the archaic laws governing the state’s water stocks, Mr Redman said it seemed some major licensees were running sprinklers just to use a minimum quota of their allocation. He said the practice was endangering WA’s development and he had sought advice on what “legislative options” he had to stop it. Under WA’s water legislation, prospective users are required to seek a licence from the Department of Water, which then permits or refuses it, depending on availability of water in an area. Licences typically last for about 10 years.
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CrossCurrent Work has begun to connect Hyden residents to an innovative wastewater scheme, the first of its kind in Western Australia. The $3.6 million trial was supported by 90 per cent of the town during a community poll in 2011 and is part of the State Government’s infill sewerage program. “Hyden’s STED system will take wastewater that has already been treated in household septic tanks through a pipeline system and to a disposal pond located outside of town,” said Water Minister Terry Redman said.
Queensland Close to 90 per cent of Mackay’s treated effluent is recycled and used for irrigation by cane farmers, reducing demand on groundwater by 8,500 mega litres per year. Greg Plath has a 47mega litre dam that is supplied with treated effluent water and says it gives him a sure water supply, which is priceless in times of drought. Mr Plath says more farmers are looking for another scheme like this, but isn’t sure the support is there. “There was federal, state and local government support when we built this one. I know there are farmers knocking on the door to Mackay Regional Council all the time wanting to be part of this.”
Unitywater has completed a significant engineering achievement, drilling an 820-metre sewerage pipeline under the Maroochy River on the Sunshine Coast as part of its innovative solution to cater for growth in the area. The pipeline beneath the river marks the first stage of a three-stage project that will see the closure of the Suncoast Sewage Treatment Plant (STP) and the transfer of the sewage to the Maroochydore STP, which has the capacity to fully treat it.
For the first time, a uniform code will apply across South East Queensland for the design and construction of new water supply and sewerage assets, making it easier for developers, engineers, consultants and service providers to deliver water infrastructure. The five South East Queensland (SEQ) water service providers – Gold Coast City Council, Logan City Council, Queensland Urban Utilities, Redland Water and Unitywater – worked together to develop the new SEQ Water Supply and Sewerage Design and Construction Code (SEQ Code) that became effective on 1 July.
Member News Water treatment specialist Degrémont, a subsidiary of utility company Suez Environnement, has won the contract for the design, construction and commissioning of a 1000m3 per day wastewater membrane filtration system, SmartRack, for Thales Australia at its Mulwala facility in New South Wales.
AECOM has authored the fifth edition of Wastewater Engineering: Treatment and Resource Recovery, published by McGraw-Hill Higher Education. One hundred years have passed since the initial publication of the Metcalf & Eddy Book. Numerous updates and editions have been published to keep pace with technical developments, regulatory changes and evolving systems. The book has become the staple in wastewater engineering courses and a reference design text for practicing engineers worldwide.
WATER NOVEMBER 2013
Veolia Water Australia has won a nine-month contract with Energy Resources of Australia Ltd (68.4 per cent owned by Rio Tinto) for the operations and maintenance of the Brine Concentrator at Ranger Mine in the Northern Territory.
Gary Crisp, Global Business Leader – Desalination at GHD, has been re-elected as a director of the International Desalination Association (IDA) for 2013–2015. He is the only Australian of the 16 elected members. The IDA is the leading information and professional development body for the global desalination industry.
URS welcomes Greg Johnson as Principal Civil Water Engineer in the Melbourne office. Greg has over 20 years of experience in the water industry, incorporating investigations, design, documentation, estimating, tender evaluation and contract administration. He specialises in being the Project Manager or Design Manager for projects involving the design of pump stations, pipelines, water storages and treatment plants.
Austrade, together with the Department of Industry and waterAUSTRALIA–AWA, invites Australian water technology and solution providers to join the Australian Water Solutions Mission to China to develop new business in the industrial provinces of Jiangsu and Guangdong, and to be part of the Australian Pavilion at Water Expo China + Water Membrane China 2013 (WEC 2013) held in Beijing from 2-4 December 2013. This mission will be led by Australia’s Water Supply Advocate, Bob Herbert, AM. Program arrangements, including industry seminars, networking events and the Australian Pavilion will be supported by the Australian Department of Industry and Austrade.
The next NCEDA International Desalination Workshop, The Politics and Practice of Desalination, takes place from 28–29 November and includes an impressive line-up of speakers from around the globe. The workshop is being held in collaboration with the Gwangju Institute of Science and Technology (GIST), Republic of Korea. The workshop will showcase some notable international desalination success stories, such as the Megaton Project in Japan. There will also be presentations from the Singapore Membrane Technology Centre and the King Abdulla University of Science and Technology in Saudi Arabia, and talented Australian and Korean researchers will provide a broad overview of desalination research being undertaken in both countries. AWA members are eligible for the discounted ate of $990. For more information and to register, visit the NCEDA website.
Monadelphous Group has been awarded new maintenance services and infrastructure construction contracts with a combined value of approximately $250 million. The contracts are for work in the oil and gas sector in Western Australia and the water sector in Queensland.
AWMA’s i-RiserTMPLUS has won the Telstra Technology and Innovation Award at the 2013 Elmore Field Days. This new patented vacuum breaking technology was designed and developed by AWMA Water Control Solutions and mitigates hydraulic issues that cause pipelines to fail.
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POSTCARD FROM INDONESIA – from Dr Dewi Kirono & Grace Tjandraatmadja A CSIRO team is involved in a collaborative research project that helps to manage sustainable urban water supplies in a changing climate in Makassar City, Indonesia, in collaboration with Hasanuddin University and government agencies. Like many other cities throughout the world, Makassar faces challenges from high rates of urbanisation, population increase, decaying infrastructure, the need for expansion to keep up with urban growth, financial and capacity constraints and, potentially, climate change. The city’s MDG target is to provide clean water supply to 78% of the population by 2015; however, currently only 62% out of a population of 1.3 million have access to mains water – the rest rely on groundwater or carted water. The city – the largest and most urbanised in eastern Makassar City. Indonesia – will continue to face water shortages over the next few decades unless it can develop alternatives for sustainable water management. And, importantly, this will require shifting from reliance on large infrastructure alone to solutions that combine infrastructure and preventive measures, such as demand management and behavioural changes, in the future. These were key messages from the two-year research project.
CURRENT AND FUTURE CHALLENGES Firstly, the project investigated the current and future water services challenges in the region and developed new data, including projections of future regional climate and its medium-term impacts on streamflow of rivers – the region’s major raw water resources – previously unavailable. Then the project examined the potential for bulk and clean water supply to service the urban demand under a range of scenarios based on population projections, water consumption patterns, leakage in distribution, infrastructure upgrade plans, climate options, and so on. Finally, the project worked with the locals to understand future implications, introduce total water cycle and integrated water management concepts, and explore potential adaptation options to improve the sustainability of water supply. This resulted in a number of suggestions proposed for further investigation such as ”biopori” – a locally developed technology for groundwater recharge and run-off reduction – upgrade of water treatment plant capacity and water reuse, an education/awareness raising program and, in the long term, the exploration of alternative water supplies from greywater treatment, among others. Participatory approach and capacity building were the project’s foci, aimed at enhancing capacity to mainstream climate change into planning and adaptation programs in the water sector at local level. More than 250 staff of government agencies, NGOs and universities participated in project activities over two years. Seven participants from Makassar spent two weeks in Melbourne to undertake training, study tours and interact with Australian scientists, water utilities, government agencies, and practitioners, learning about the Australian experience on adaptation to climate challenges and sustainable water management. The project was one of the research initiatives of the Research for Development Alliance, which is a strategic partnership between AusAID and CSIRO to improve the impact of aid. Dr Dewi Kirono (email: email@example.com) is a Senior Research Scientist who leads the Impact, Adaptation and Vulnerability Research Team within the CSIRO Marine and Atmospheric Research (CMAR) Division in Aspendale, Australia. Her works focus on integrated climate change impacts and adaptation assessment. She led the project described in this article and can be contacted for further details.
Makassar water company’s water treatment plant.
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Grace Tjandraatmadja (email: Grace.Tjandra@csiro.au) is a Research Scientist with CSIRO Land and Water (CLW), Highett, Australia. She is studying transition strategies to improve the sustainability of urban infrastructure and technology uptake.
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SCA SAYS LONGWALL MINING IS A THREAT TO SYDNEY WATER SUPPLY The Sydney Catchment Authority has warned that longwall mining in Sydney’s drinking water supply catchment poses a serious risk to water supply – which should come as no surprise to the O’Farrell Government, Total Environment Centre (TEC) said today. In a submission on proposed changes to mining laws, the Authority warned that under the new regime there would be increased damage to water quality and quantity, along with water supply infrastructure. “Prior to the last election the Premier stood up wearing a ‘Water Not Coal’ T-shirt and promised to protect drinking water catchments from mining with a ‘No ifs, no buts’ guarantee,” said TEC Director Jeff Angel. “Since then we have heard nothing. The Premier and his key ministers have dodged the issue and instead have engaged in the introduction of new laws that make it easier for companies to get a green light to mine in these critical water supply areas. “We have seen the recent damage at Mt Sugarloaf. We have seen terrible destruction occasioned to the Waratah Rivulet providing 30 per cent of the water to Woronora Reservoir. Cracking to the bed of the Upper Cataract River from the Appin Mine saw methane bubbling to the surface in volumes that allowed the river to be set alight. The Dendrobium Mine is currently dehydrating endangered swamps vital to the functioning of the water supply catchment. “Further to this there is currently a proposal by Gujarat NRE to undermine critical parts of the water catchment with experimental mining techniques, despite an appalling track record both on environmental and financial compliance terms. This proposal has really been the last straw. “In almost every case government agencies, such as the SCA, have objected to all or part of the mining proposals prior to the damage occurring. But successive governments have proceeded with mining against the agencies’ recommendations. This is a crisis of their own making and it’s time to deliver on the promise of full catchment protection,” Mr Angel concluded.
$55M INVESTMENT TO MAKE ADELAIDE’S SOUTH ‘WATER-PROOF’ A five-year $55 million investment in alternative water infrastructure is now complete, laying the foundations for a sustainable water future across SA’s largest metropolitan council. Stage 2 of the ‘Water Proofing the South’ project was completed in June by the City of Onkaparinga at a cost of $30 million, with support from the Federal and State Governments. “Completion of Stage 2 makes this the biggest and best project of its type in South Australia and we’re very proud to be leading the charge for water sustainability,” said Mayor Lorraine Rosenberg.
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With Stages 1 and 2 complete, the council now has the capacity to capture, store, treat and reuse 3.6 billion litres of stormwater annually, equivalent to almost 1,500 Olympic swimming pools. “This project delivers treated stormwater for irrigation, greater biodiversity within the project’s wetlands, and better quality water being discharged to the marine environment,” she said. “We now have an integrated system of aquifers, seven wetlands and a 23km pipe network across the city that supplies water to parks, reserves, schools and sports fields.” City of Onkaparinga CEO Mark Dowd says ‘Water Proofing the South’ delivers both environmental and economic benefits that will support growth in the City. “There are potential economic development outcomes associated with the council providing an alternative source of water for industrial customers, developers and civil contractors,” he said. Mr Dowd highlighted further benefits including improved flood mitigation, in particular for Pedler Creek and the upper reaches of the Field River, and greater public amenity for residents.
CHIEF MINISTER OPENS COTTER DAM Chief Minister Katy Gallagher officially opened the Cotter Dam as part of the Cotterfest celebrations, handing the area back to the people of Canberra following completion of construction. The dam will support the economic growth and development of Canberra and the ACT through its next 100 years, providing long-term water security. Ms Gallagher was delighted to mark the completion of the dam, saying: “A project of this scale has had significant economic benefits for the ACT economy through an active construction sector and the creation of hundreds of jobs. I would like to thank the Bulk Water Alliance for their professionalism in undertaking this massive project and the Board of ACTEW and Mark Sullivan and his staff for their dedication, oversight and management of this very complex project. “This is an historic day for the ACT and this major infrastructure project is evidence that Canberra is a 21st century city where investments made now will pay off for the future benefit of the city.” The original Cotter Dam was completed in 1915, securing a permanent water supply for Australia’s new capital. The location of the city itself was chosen because of the abundance of water within the catchment, with Acting Chief Engineer Ernest de Burgh stating that: “It is impossible to imagine a catchment from which a purer supply of water could be obtained.”
ENGAGING STUDENTS WITH MATHS AND SCIENCE A new suite of online resources has been launched to help teachers stimulate interest and engagement in mathematics and science among Australian school students. The disengagement of students from maths and science is an alarming trend given the national priority that is assigned to these fields of study. Between 1992 and 2010, the percentage of Australian Year 12 students enrolled in Biology fell from 35.3% to 24%; in Chemistry from 22.9% to 17.2%; and in Physics from 20.8% to 14.2%.
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Research commissioned by Australia’s Chief Scientist, Professor Ian Chubb, revealed that Australia was part of a global decline in student engagement in science and mathematics. Despite this broad decline, it is recognised that there are some Australian schools that provide students with strongly positive and inspirational experiences in maths and science. In response to the Chief Scientist’s report, the Department of Education, Employment and Workplace Relations asked the Australian Institute for Teaching and School Leadership (AITSL) to identify and capture on video such inspirational teaching and participation in schools across Australia. This was done in collaboration with several organisations including the CSIRO’s Education Unit. In those schools, both primary and secondary, authentic reallife maths and science classes were filmed in action – totalling 150 minutes of stimulating teaching practice. Within all the varied classroom environments, there was a consistently strong emphasis on blending innate student curiosity with creativity, practical collaboration and problem-solving skills. The new resources will be shared internationally with the United States National Academy of Science, which has undertaken work on a similar project on behalf of the National Science Foundation. The exchange is expected to benefit both Australia and the United States. The video snapshots are available online at www.teacherstandards. aitsl.edu.au/Topics/MathScienceTeaching.
HOW CLOSE ARE WE TO A MAJOR CLIMATE TIPPING POINT? Australian film-maker Liz Courtney has made one of the largest bodies of works on our changing Climate System this year with a preview halfway across the world in the US on NBC Universals’ channel, The Weather Channel, which reaches over 150 million homes in the US.
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Together with the assistance of NASA, NOAA, leading scientists and universities from all over the world, The Tipping Points is a six by one- hour series that follows scientists in the field at the frontline of our changing climate system, as they aggregate data to be analysed and provide a timeline to change on this planet.
November 2013 water
Industry News Directed by Ms Courtney and presented by climate journalist and adventurer Bernice Notenboom, The Tipping Points embraces commentary from leading climate scientists surveying the complexity of the major tipping points, where and how they are changing and the effects this will have on our current climate system and weather patterns around the globe. From the canopies of the Amazon to the ice sheets of the High Arctic, these climate specialists chase answers to behavioural patterns of tipping elements in the climate system affecting our weather systems, making extreme weather scenarios more common. The series explores what is happening at the most dramatic tipping points and looks to find answers to understand what can be done to stem the tide of change before we do irreparable damage, and ultimately put our own lives at risk.
DESALINATION LEADER RE-ELECTED Gary Crisp, Global Business Leader – Desalination at GHD, has been re-elected as a director of the International Desalination Association (IDA) for 2013–15. He is the only Australian of the 16 elected members. With 34 years of water engineering experience, Gary is currently working on Carlsbad, Huntington Beach and Camp Pendleton desalination plants in California, USA, and the Rosarito Beach plant in Mexico.
FIRST DIPLOMA OF WATER OPERATIONS IN QUEENSLAND Seqwater has partnered with South Western Sydney Institute (SWSi) to develop the first Diploma of Water Operations offered in Queensland. Chief Executive Officer, Terri Benson, said Seqwater wanted to increase the leadership capability of its team leaders and supervisors in the water treatment and dam operations areas. “Sixteen people from a range of operational, technical and scientific areas across Seqwater completed the diploma, which was delivered through a combination of face-to-face workshops and online learning,” Ms Benson said. “Delivering the diploma course work in this way took into account the geographical spread of our business. “The diploma has strengthened the technical skills of our employees, as well as provided leadership skills for the future. It has also helped us to build more developmental pathways for our staff. Participant feedback on the course and the trainers has been very positive.” The participants started the diploma in July 2012 and completed it in June 2013. The coursework was delivered through six face-to-face workshops, each taking one to two days. The online component of the diploma was used for research, to download materials for each workshop and to upload assessments. At the end of each workshop, participants completed an evaluation to enable SWSi to understand what was working well and what areas needed improvement.
Gary was instrumental in delivering Australia’s first major desalination plant in Perth, Western Australia. “There is no doubt that without desalination the city would have run out of water,” he says. GHD has worked on 14 plants in the country in total, including the Big Six built to supply the major cities. “Australia’s major desalination plants show the world that desalination is a sustainable solution to water shortages and climate variability,” Gary says. “The plants’ energy needs are offset by agreements to purchase electricity from renewable sources. The facilities also meet strict discharge and environmental monitoring requirements.” Gary is also passionate about water reuse based on similar reverse osmosis technology to desalination. GHD’s experience in desalination and water reuse is in demand around the world as utilities strive to secure their water supplies. The company has been involved in projects in Africa, China, India, Mexico, the Middle East and the USA. “Desalination and water reuse are a climate-independent source of water and the technology is constantly improving. Our team has extensive experience serving both urban utilities and industrial clients,” Gary says.
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Seqwater Ceo, Terri benson, presents bruce Fischer, Seqwater Works Coordinator, Capalaba Water Treatment Plant, with his Diploma of Water operations.
UNITYWATER COMPLETES PIPELINE UNDER MAROOCHY RIVER Unitywater has completed a significant engineering achievement, drilling an 820-metre sewerage pipeline under the Maroochy River on the Sunshine Coast. The pipeline marks the first stage of a three-stage project that will see the closure of the Suncoast Sewage Treatment Plant (STP) and the transfer of the sewage to the Maroochydore STP, which has the capacity to fully treat it.
Industry News The $11 million project will also incorporate a sixkilometre 560mm diameter pipeline and a new transfer pumping station to connect the existing sewerage network north of the river to the Maroochydore STP via the sub-river pipeline.
Because traditional excavation and trenching was not possible under the Maroochy River, Unitywater used horizontal directional drilling (HDD) to install the pipeline, avoiding any unnecessary environmental impact and minimising surface disruption. Unitywater appointed Coe Drilling Pty Ltd to conduct the horizontal directional drilling of the transfer pipeline. Construction commenced in July and the pipe was pulled under the Maroochy River in early September. This project is part of the $680 million capital works program Unitywater is rolling out over the next five years to increase the network capacity and cater for future population growth in the Sunshine Coast and Moreton Bay regions.
Unitywater Executive Manager, Infrastructure Planning and Capital Delivery, Simon Taylor, said the Suncoast STP is operating at capacity and Sunshine Coast Council’s original plan to expand the facility to cater for anticipated population growth in the area was estimated to cost $34 million.
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The project maximises existing assets and defers the need for expensive infrastructure upgrades, saving around $20 million. “Building the pipeline to a plant which already has capacity available is a much less expensive and more environmentally-friendly solution, saving millions of dollars in capital works and ongoing operational expenses to keep costs as low as possible for our customers,” Mr Taylor said.
Australian company Climate Risk Pty Ltd has registered international patents for climate change adaptation software for property and infrastructure assets. Designed by scientists, engineers and financial risk specialists, the ‘Resilience Engine’ claims to have broken through the long-standing barriers to pricing the inevitable impacts of climate change to specific assets and evaluating the benefits of adaptation. The ‘Resilience Engine’ technology has taken three years and US$2m to develop and analyses hundreds of infrastructure and building assets simultaneously, cross-referencing them with extreme weather maps
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Industry News and climate change data to quantify the risks from hazards like extreme weather and sea level rise. The system automatically forecasts the annual costs of the impacts, insurance premiums, and can even project the future change in value of the assets. Dr Karl Mallon, Director of Science and Systems at Climate Risk stated: “The Resilience Engines address a fundamental gap in business intelligence: the chasm between climate science and asset planning. To cross the divide we turn maps and probability distributions into dollars, cents and cost projections. It might seem a small gap, but its takes serious maths, maps and computing power to bridge that divide. What currently takes months of expert consulting time, we have captured in sophisticated software that runs 10m risk calculations per minute.” Climate Risk is currently negotiating deployment arrangements with transnational cloud-computing providers for commercial rollout in Australia and the US.
KEY AURECON APPOINTMENT Leading water engineer Craig Berry has joined Aurecon as the Unit Manager for its water team based in Brisbane. Craig has moved to Aurecon from Jacobs, where he was the director of its water division in Glasgow and managed Scottish Water’s £800 million capital works program. In his previous role at GHD, Craig was the Design Manager for the AUD 2.5 billion Western Corridor Recycled Water Scheme named Global Water Project of the Year in 2008. Aurecon Water Services Group Leader Tobie Louw said: “Craig brings great knowledge of the Queensland water business together with fresh perspectives obtained through his years with GHD and Jacobs.” Craig has over 24 years of experience in civil engineering, with particular emphasis on water-related projects. He has led a number of multidisciplinary integrated teams operating within partnering arrangements and framework contracts including the AUD900 million Traveston Crossing and Wyaralong Dams project in Queensland. In his role as Water Unit Manager Brisbane, Craig will focus on growing long-term relationships with Aurecon’s water clients to align solutions to business needs. Aurecon offers a range of integrated water solutions that address every element of the water cycle.
LEIGHTON CONTRACTORS WIN SAFETY EXCELLENCE AWARD Leighton Contractors was awarded the 2013 Queensland Project Safety Excellence Award at a gala dinner attended by around 400 construction industry leaders at the Brisbane Convention Centre last month. The Awards are run annually by the Queensland Major Contractors Association (QMCA), the peak body representing the state’s engineering construction industry. Sponsored by Herbert Smith Freehills, the Award is Queensland’s highest construction safety accolade, recognising a project team’s
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commitment to safety in the construction of major government and private sector infrastructure projects. Leighton beat 13 other high-profile contenders to take the prize for their Australia-Pacific LNG Upstream Water Treatment Facility Project at Condabri, near Miles in Central Queensland. The project involves constructing water treatment facilities and storage ponds to treat water produced by Australia Pacific LNG’s coal seam gas wells, with a goal of producing water that can be used for irrigation. Judging Panel Chair, Harold Downes, said the Leighton entry demonstrated a combination of innovation, simplicity and executive commitment, best responding to Award criteria, which this year focused on innovation. “A key aspect of the project included the innovative and effective processes engaged by the project team including trialling a Smart phone App to analyse and diagnose safety risks in the workplace.” QMCA President Tony Hackett said there had this year been unprecedented interest in the Award with 14 nominations received despite challenging business conditions for the sector.
VINSI APPOINTS NEW CIVIL ENGINEER Vinsi Partners has announced that Barry Gentle has joined their Newcastle Office as a Lead Structural/Civil Engineer. Barry has over 19 years of experience in the fields of Structural and Civil Engineering with both contractors and consultants. In the UK, he managed numerous underpinning and remedial repair projects for domestic properties suffering subsidence, and also carried out the structural design for a £3M sports hall. He has worked in Australia since the year 2000, and has been responsible for the design of many reinforced soil structures for road, rail and mining applications. He has also worked abroad, providing reinforced soil design tuition and design verification for a highways project in Bangkok, as well as supervising site works for a dump wall at a mine in Papua New Guinea. Work on a number of significant projects across industry sectors such as rail, desalination, and mining was also undertaken. Barry was previously based at PB Newcastle and managed the structural engineering, drafting, and water engineering teams.
ORICA ANNOUNCES SENIOR MANAGEMENT CHANGES Orica Ltd has announced that Nick Bowen will join Orica as Executive Global Head Mining Services, bringing with him a strong background in the mining and mining services sector spanning over 30 years. Most recently Mr Bowen was Managing Director at Macmahon Holdings Ltd, a position he held for 13 years. Mr Bowen is a highly experienced senior manager with deep experience in the sector and across international operations. The appointment follows a global search to fill the role. Meanwhile, Craig Elkington has been appointed as Chief Financial Officer. Mr Elkington will now commence the formal handover process with outgoing CFO Noel Meehan, who will leave Orica at the end of October.
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REGIONAL GRANTS INITIATIVE OPENS NEW ROUND OF FUNDING After an overwhelming response in its first year, an initiative that benefits regional Australia today has opened a new round of cash grants for community groups with water on their minds. The Philmac Project will provide individual cash grants of up to $5000 to local organisations wanting to carry out water-related projects that benefit rural and regional communities. The funding scheme is the initiative of leading Australian manufacturer Philmac, which has been designing, manufacturing and distributing fittings and valves for polyethylene pipes in Australia for more than 80 years. “We launched The Philmac Project last year as a way of giving something back to the rural communities that have stood by us over the years, despite challenging times both for rural water users and local manufacturers,” said Philmac Managing Director, Mark Nykiel. “Judging by the extraordinary response, stretching from outback Queensland and the Northern Territory to southern Tasmania, it met
a significant need, particularly in smaller communities, so we have decided to offer another round of grants this year. Applying for a grant is easy. Submissions are made online via either the Philmac website or a dedicated Facebook page, using a simple application form that asks a few basic questions about the intended project. The submissions will then be posted on both Facebook and the website so that people can show support for the projects by voting. The five projects in each region that attract the most votes will be short-listed for final judging by an expert panel. To qualify, a project must be located in a regional area, and the work has to be completed within 12 months of the start date. Applicants can lodge submissions online until December 20, 2013, however the sooner the application is made the more time they have to generate votes. For more information and to make a submission please visit www.facebook.com/PhilmacAustralia or www.philmac. com.au/PhilmacProject
USING WASTE SEASHELLS TO SOLVE WASTEWATER PROBLEM The thousands of tonnes of waste seashells created by the edible seafood sector are being put to use by the University of Bath in a new wastewater cleaning project. Dr Darrell Patterson, from the University’s Department of Chemical Engineering, used waste mussel shells to create a cheaper and more environmentally friendly way of ‘polishing’ wastewater, which could be used to remove unwanted substances such as hormones, pharmaceuticals or fertilisers.
Philmac managing Director, mark Nykiel.
Traditional wastewater treatment broadly takes three stages. The first involves the removal of any solids and oils, the second filters the water and degrades the biological content of the sewage, which is derived from human waste, food waste, soaps and detergent.
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Find out more about our holistic ethos at water November 2013 onestoneconsulting.com.au or call (08) 6161 2361
Industry News Finally a tertiary treatment is used to further improve the quality of the water before it is released. There are different methods of tertiary treatment, and one of the most effective is the photocatalysis of water to remove any final trace contaminants. This process normally uses titanium dioxide, which is expensive. By replacing this with a material from the calcium derived from seashells called hydroxyapatite, which can also be found in teeth and bones, Dr Patterson is aiming to significantly reduce the cost and reusing a renewable unwanted waste product. Dr Patterson said: “Mussel and other seashell farming is a fast-growing industry around the world and the increase in the production of shellfish generates a large amount of shell waste. Shells are a calcium-rich resource that can be used to produce calcium oxide (lime). This lime can be used in several different ways in environmental technologies, and our study has shown that the hydroxyapatite formed from them is an effective, green and potentially cost-efficient alternative photocatalyst for wastewater treatment.”
PRICING WATER FOR MORE EFFICIENT USE Flat-fee water charges are still common in parts of Europe. Such schemes, where users pay a fee regardless of the volume used, do not encourage efficient behaviour, either in households or agriculture, according to a new report from the European Environment Agency (EEA). The study, ‘Assessment of Cost Recovery Through Water Pricing’, considers water pricing in several EU countries, such as Croatia, England and Wales, France, Germany, the Netherlands, Scotland, Serbia, Slovenia and Spain.
The research was carried out using mussel shells, but other types of seashell could feasibly be used to produce photocatalysts, making this technique globally applicable. The project will now go on to look at the wider applicability of this technology and the scaling-up of shell-based photocatalysts to industrial level.
Water is under stress in many parts of Europe. Even in regions that usually experience a high level of rainfall, abstracting and cleaning water can have a high economic and environmental cost. In response, the report states that water should be priced at a level that both encourages efficient use and properly reflects its cost. This should include all costs of purifying and transporting the water. In addition, environmental and resource costs of water use, such as pollution and the depletion of resources, should also be internalised into water prices. Such charges should factor in lost ‘ecosystem services’, which also require water – for example, wetlands carry out valuable services such as water purification and flood prevention.
For more information on this area of research you can follow @DrDAPatterson on Twitter, or access the full text research paper online at: opus.bath.ac.uk/34853/
The EU Water Framework Directive called for Member States to create incentives for efficient water use by 2010. However, it is unclear whether this has resulted in any change in national policies.
O P E R AT E
Everything we’ve learned about water technology comes down to one thing: RELIABILITY
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November 2013 water
Young Water Professionals
5 TIPS FOR GETTING AHEAD IN The Corporate World Jo Greene – AWA YWP National Committee President
Have you ever felt as though you don’t know the rules of the work environment, or how the game is played? Do you ever have a sneaking feeling that there was an information session to explain the rules of the game, but somehow you missed it? After giving the subject some thought, I’ve come to the conclusion that it’s important to understand how the corporate world works and how the game is played. Through my experience in the corporate workplace, I have come to believe the following two points. They may seem harsh, but I found once I accepted them to be the case I was in a much better position to go forward! 1.
The corporation is there to answer to the shareholders. They may consider what is in the best interests of the employees, but their first priority will be the shareholders.
No-one will care too much if you quit or leave, so don’t kill yourself for the corporation. No one person is indispensable. Unfortunately even the Managing Director or Chair of the Board can be easily and quickly replaced.
Having said all that, the best way to survive, stay motivated and get ahead in the corporate world is to learn to play smart. Here are some tips to help you stay ahead of the game.
1. Don’t Care about the wrong things You should care about the people. Care about the work. Care about your manners and your attitude. But you should stop caring about the gossip, the company news, and the decisions that come from
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the top that don’t resonate with you. Don’t be concerned about changes to process, policy and perks that are most certainly not designed to please employees in general. Caring about the wrong things does not serve you well. It accomplishes nothing and will drain your motivation.
2. Focus On the work that matters It’s not how hard you work, it’s how smart you work. Learning to say no to trivial jobs takes guts, but you need to do the work that matters to the bottom line of the company and to your team. When you are asked to do work as a ‘favour’, start with an apology but explain that although you would love to help, you have too much on with your current projects. Once you learn how to differentiate the important work from the white noise, you will gain focus and a healthier balance to your work. Assess whether you really need to go to every meeting and answer every email. You will find that the top performers do very little of this and spend their time focusing on the really significant work. Make sure you know why you are doing the work you are doing. If you don’t know the answer to this, then ask your supervisor or manager. Is your work going to have an impact? Or are you working on some dead-end corporate initiative that will leave you feeling empty and unmotivated? If you make smart choices and draw the line when and where it needs to be drawn, that line will bring you respect.
Young water Professionals relationship of learning, dialogue and challenge. This will be beneficial to you both. Build a network by meeting and getting to know people whom you can assist, and who can potentially help you in return. Do this through your workplace and any other opportunities available such as member organisations, training, seminars and conferences. A network can include everyone from friends and family to work colleagues and member of groups to which you belong. Benefits of networks include fresh ideas and information, raising your profile, access to opportunities, and advice and support.
5. keeP a PositiVe attituDe 3. take ControL oF Your own Career Putting your career in your managers’ hands is not advisable. You may have good managers, and you may like and appreciate them, but it doesn’t necessarily follow that just because you like your team or your company that they love you in return. You need to be in charge of your own career and drive it forward. When opportunities arise, first decide if they align with where you want to end up. If not, then decline. You decide where to go next, how long to stay on the team, and even what projects you are going to work on. Have a voice about your career, because no-one else will.
4. seek a mentor anD buiLD a network Find a mentor or trusted leader that you can turn to for advice and use as a sounding board. It is often best to make sure they are not in your direct chain of command. You need to build an ongoing
Attitude is everything. A bad attitude may not hurt your performance as such, but it will damage your reputation. Kindness is often quickly and easily forgotten in the corporate world, but a single episode of displaying a poor attitude may be held against you for a long time. Your attitude should be professional on every occasion. Be professional when you are asking for something, when you are frustrated, when you want to complain about something, when you are negotiating, and especially when you are sharing disappointing news or a change in plans. If you find yourself becoming cynical, gloomy, unmotivated or bored, immediately take action to change things and stop yourself falling into this trap. Finally, don’t ever lose conviction about the general goodness of people. This single approach to your work will ensure that you feel proud about the exemplary character you show others through a positive attitude.
> Reduce maintenance cost > Run dry indefinitely > Deadhead without damage > Extra thick sludge handled > Extra heavy duty
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November 2013 water
AWA 2012–2103 Annual Review Now Available The AWA Annual Review has now been released and is available for download at www.awa.asn.au/annual_reports. The financial year 2012–2013 represented the first year of AWA’s new Strategic Plan (2012–2015). The five strategic objectives in this plan are: 1.
Engaging members with valued services;
Representing the sector as a trusted voice;
Extending our reach;
Building skills and knowledge in the sector; and
AWA hopes that members will find the review an informative and engaging read, outlining as it does the achievements of AWA as an organisation, AWA staff, AWA members and the wider water community.
Vale Dr Gordon Archer AWA Member Dr Gordon Archer was born in Melbourne on 18 March 1926, just halfan-hour ahead of his identical twin brother, Harold. Later they became known as “Bow” and “Arrow”. Educated at Canberra High School and then Scotch College in Melbourne, the twins were awarded scholarships to the RMIT in 1941 where Gordon studied Metallurgical Engineering and Harold undertook Mechanical Engineering. Upon graduating in 1944 aged 18, they promptly enlisted in the Royal Australian Army Engineers and were selected for officer training and promoted to lieutenant before being sent to the 12th Advanced Watercraft Workshop in Rabaul. After the war ended, Harold remained in Engineering while Gordon opted to study Medicine at the University of Sydney at Camperdown before graduating in 1952 and marrying in 1953. Gordon’s father Richard was a pilot during the First World War. He joined the Commonwealth Public Service as an Engineer and later rose to Secretary of the Snowy Mountains Authority. Gordon’s mother Norma was one of the first women admitted to Melbourne University to study Physics and Maths. After a resident year at RPA in Camperdown, Sydney, Gordon stayed on as Pathology Registrar during 1954 and 1955. During this time he developed a close interest in the life-saving aspects of blood transfusion, including an unusual case where he managed the administration of 500 bottles of blood over three days to a haemophilia patient before bleeding stopped and the patient recovered. After one year as Head of Pathology at Wollongong Hospital, Gordon was offered the job of Deputy Director of the NSW Blood Transfusion Service in 1957. In this role he identified the first case
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of sickle cell anaemia in Australia. After being awarded a postdoctoral research fellowship by the National Institute of Health (NIH) in the US, he moved to New York to work at the Rockefeller Institute. Following further research back in Australia, Gordon was elected President of the Australian Society of Medical Research in 1965. During this time he was also involved in supporting international initiatives and was appointed Secretary-General of the XI Congress of the International Society of Blood Transfusions held in Sydney in 1966. Gordon spearheaded initiatives in the Asia-Pacific region to assist poorer nations in training and improving their blood banking operations. He was appointed Director of the NSW Blood Transfusion Service in 1967 upon the retirement of Bob Walsh, and retained that position for 25 years. Perhaps the most important period of Gordon’s career was the unravelling and management of the effects of what was to become known as the AIDS epidemic. Gordon was recognised by his peers in 1989 to become President of the International Society of Blood Transfusions, the first Australian to be so honoured. He was made an Order of Australia for services especially to blood transfusion services in 1991. Gordon did not wear these medals or adopt the title as he was never comfortable with self-promotion and preferred to recognise the achievements of his colleagues. Following retirement in 1992, Gordon joined his twin brother Harold’s business, Water Treatment Australia, in the role of Technical Director for chemical and biochemical analysis and treatment. As such he provided the business and also clients testing and guidance on complex water and wastewater analysis. Gordon was an inspiration and role model to the family of which he was so proud. He is survived by his wife, Joy, their children Sue, Martin, Tim and Megan, as well as twin brother Harold and 12 grandchildren.
Australian Stockholm Junior Water Prize Winner Each year, the Stockholm Junior Water Prize brings together young scientists and innovators from around the world who propose new solutions to the planet’s growing water challenges. Each year, thousands of participants from countries all around the globe enter national competitions with the goal of earning the chance to represent their nation at the international final held during World Water Week in Stockholm. The national and international competitions are open to young Winner Declan Fahey. people between the ages of 15 and 20 who have conducted water-related projects of proven environmental, scientific, social or technological significance. In November 2012, I entered the Australian Stockholm Junior Water Prize with a project I had researched and entered in regional and state science fairs in Tasmania. This year, I was fortunate to be selected as one of three finalists in the Australian Stockholm Junior Water Prize and flew to Sydney in March, where I had the
entrants and guests at the Stockholm Junior Water Prize. opportunity to showcase my research to a panel of judges. In Sydney, I was announced as the winner of the Australian Stockholm Junior Water Prize 2013, an achievement that would see me represent Australia in the international Stockholm Junior Water Prize in Sweden in September. I have recently returned home from Sweden and an experience which was the opportunity of a lifetime. I spent five days in the company of 55 students from a total of 28 participating countries. I met some dedicated, innovative and truly amazing young people. During my time in Stockholm, I participated in the Stockholm Junior Water Prize fair where I presented my research to an international jury – a panel of water experts from all around the world. Following the fair, I attended the winner’s ceremony for the Prize, where I had the opportunity to meet HRH Crown Princess Victoria of Sweden, who later presented the winning students from Chile with their award. The students were also treated to a royal banquet the following evening, in the company of His Majesty King Carl XVI Gustaf of Sweden and his wife, Her Majesty Queen Silvia. This was a real honour and an experience all the students will cherish. Other highlights included a guided tour of the Old City, a visit to Xylem Water Solutions, the global sponsor of the Prize, and the chance to engage in international relations with other passionate young scientists. By entering the Australian Stockholm Junior Water Prize, I have had the chance to communicate my research findings to a wider audience and am extremely grateful to my teacher/mentor, my family, the Australian Water Association and national sponsor Xylem, for the opportunity to represent my country on the world stage. This experience has shown me that science can take you anywhere. – Declan Fahey, Winner, Australian Stockholm Junior Water Prize 2013
2014 bIOSOlIDS AND SOuRCE mANAGEmENT CONFERENCE: lAST CAll FOR PAPERS The Biosolids and Source Management Conferences will be held concurrently from 25–27 June 2014. The combined conference will explore both areas and link them together to provide an understanding of the whole life cycle of the system. Themes of the conference and abstract submission guidelines can also be found at www.awa.asn. au/bsmconference. Submissions are due Friday 15 November.
uNCONvENTIONAl GAS AND WATER SHORT COuRSE This one-day course, which takes place on 21 November in Perth, provides a broad overview of unconventional gas (onshore gas) and the effects that the extraction has on groundwater resources. With onshore gas currently at exploration stage in WA, this course is designed to keep participants abreast of current industry developments. The course will be based on the latest scientific research and industry practice in regards to water management – one of the critical operational challenges of working with unconventional gas. The preliminary program and registration is available at: www.awa.asn.au/unconventionalgas
November 2013 water
awa News North Queensland Regional Conference 2013
ARE YOu lOOkING FOR A WATER SCHOOl CuRRICulum RESOuRCE? In celebration of the release of their online units, the Australian Academy of Science has decided to release its Science by Doing: Enough Water Fit for Drinking and Doing Science Investigations in hard copy at no cost (other than postage and handling) until present stocks run out. For more information please visit the Science by Doing website at science.org.au/sciencebydoing/. This is just one of the many resources that has been quality assured by AWA’s Australian Curriculum Water Project through its audit process. For more information or to subscribe, please visit the AWA website.
bRANCH NEWS QlD Central Queensland (CQ) Technical Seminar On Wednesday 31 July, Fitzroy River Water (part of Rockhampton Regional Council) hosted AWA’s inaugural CQ Technical Seminar. The event was attended by approximately 20 delegates and was timed to coincide with the Qldwater Central Queensland mini-conference in Rockhampton the following day. AWA is appreciative of the support from Qldwater in helping coordinate the two events. Delegates from Rockhampton, Mackay, Biloela, Gladstone and SEQ joined the seminar and were treated to an excellent program of speakers with a particular focus on energy usage in wastewater treatment:
From 28–30 August, Townsville turned on some beautiful late winter weather to host over 100 delegates for this year’s NQ Conference. Townsville Water and Townsville City Council were wonderful hosts and it was great to see momentum continuing in spite of challenging conditions around the industry. An optional site tour was hosted by Townsville Water on the afternoon before the main conference. The group reviewed the recent upgrade works at the Mt St John WWTP and Douglas WTP and there were some great discussions about the unique challenges of water and wastewater treatment in the dry tropics of NQ. Attendees also got up close and personal with the innovative team and excellent facilities at Townsville Water’s laboratory hearing about the services that the lab offers. Delegates heard about a range of topics including: • The big picture of water availability across Northern Australia; • An up-to-date picture on the challenges to the health of the iconic Great Barrier Reef; • Views on opportunities and challenges of potential collaborative arrangements in NQ; • Challenges in managing fatigue in our operational workforces and in engendering a safety culture in the water industry; • Applying a strategic view to procurement to keep up with evolving requirements; • Moving beyond compliance requirements and creating useful management tools;
• Cameron Staib from MWH discussed “Driving Energy Efficiency and Reducing Operating Costs at WWTPs”. Cameron outlined the connection between technical optimisation opportunities, risk appetite and human behaviour in identifying opportunities, committing to them, implementing them and making benefits stick.
• Demystifying some of the legal concepts relating to climatic challenges in construction and operational contracts;
• Simon McKenzie from Tenix presented on the “Whitsunday STPs Upgrade Project” with a focus on the application of Infrastructure Sustainability Rating.
• The importance of getting water in the right place at the right time – from source to customer tap.
• Ian Kikkert from the Water and Carbon Group gave a talk on “Low Energy Integrated Infrastructure Solutions”. His talk highlighted the use of ecological infrastructure (such as high-density treatment wetlands) as part of an overall treatment solution. The group also viewed a recorded Technical Program event from earlier in the year on “Infrastructure Delivery Models”. AWA hopes to establish a semi-regular group meeting in the CQ Region to discuss both local, state wide and broader technical content. Evan Davison from Fitzroy River Water has kindly offered to help coordinate future events in the region so if you have any feedback or ideas please drop Evan an email on email@example.com. Part of the Queensland Branch Committee’s focus for 2013/14 will be to follow on from the success of our Technical Program and conferences in SEQ and NQ with the delivery of more value for members in other regional areas. Kevin Flanagan from Toowoomba RC is coordinating this effort so please feel free to drop him a note on Kevin.Flanagan@toowoombaRC.qld.gov.au with suggestions.
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• How regulatory requirements are driving capital investment in treatment systems and also some of the ongoing efforts to optimise energy and chemical usage in operating plants;
• Private sector innovations in optimising delivery and operation of infrastructure as well as building sustainability into projects. At the conference dinner attendees heard an “around the grounds” update of the big picture issues from key water directors in Cairns (Paul Utting), Townsville (Keith Parsons) and Mackay (Jason Devitt). A particular treat for those who survived the dinner festivities was the site visit to James Cook University. We met a passionate group of researchers who are using cultured algae to treat water, sequester carbon dioxide and create a mind-boggling range of commercial products. The energy of the team and the potential positive impacts of the concepts at a commercial scale were impressive. Congratulations go to the Townsville City Council and TRILITY team who won the best paper with a presentation on “Upgrading and Optimising Treatment Plants”, which covered both collaborative delivery models as well as technical optimisation concepts. A big thanks must go to all sponsors and exhibitors and to Sharon Ible and the organising committee for their hard work.
awa News NSW Water Sensitive Cities Seminar The last NSW Technical Seminar for 2013, Seminar 6 Water Sensitive Cities: A Look at Local and International Case Studies, was held on 18 September 2013, with 70 people attending from a range of organisations as well as interstate delegates. The seminar provided attendees with insights into best practice case studies from around Australia, as well as some international case studies on integrated water cycle management. Sally Armstrong, Manager of People and Places at Sydney Water, discussed the challenges ahead in addressing this growth and presented Sydney Water’s vision of engaging with customers to better understand their needs and priorities and to work with them and other stakeholders to plan for a more liveable Sydney.
phase of a new seminar series for 2014. Your suggestions for topics are welcome and can be forwarded to nswbranch@awa. asn.au. AWA would like to thank the seminar sponsor Sydney Water for their continued support.
ACT ACT Water Leaders Dinner The ACT Water Leaders Dinner was held on 5 September at the Boat House by the Lake in Canberra. With over 50 of water’s leaders in attendance from a range of organisations, the evening generated interesting and progressive conversations about a range of current and impending water issues.
Terry Leckie, Managing Director of Flow Systems, presented interesting case studies about water recycling and management in recent property developments in Green Square and Discovery Point.
Incoming ACT Branch President, Adrian Piani from URS, thanked the previous ACT Branch President Simon Webber for his outstanding contribution to AWA. Adrian Piani reminded the attendees of Canberra’s controversial Skywhale hot air balloon before introducing the evening’s special guest speaker, Mike Waller, CEO of the Office of Living Victoria. Mike discussed Victoria’s integrated water cycle management and its transformation, puddles and pitfalls, including changes in strategy and approach. He highlighted how this transformation will provide better outcomes for communities, and will deliver secure and affordable water services and how the ACT might leverage from Victoria’s experiences.
Django Seccombe, Technical Advisor at Sydney Water, presented international water-sensitive cities case studies from a 2012 study tour of Northern Europe and Singapore. He found that Europe was a better long-term planner of water than Australia. AWA is in the planning
AWA thanks the event sponsor ACTEW Water and GHD for sponsoring a table at the event.
Steven Wallner, Principal Engineer of Strategic Water Planning at AECOM, discussed some of the key projects that he has been working on with the Office of Living Victoria. Projects highlighted by Steven included Troupes Creek stormwater scheme and western Melbourne greening project to decrease heating of inland urban areas. Greg Ingleton, from SA Water, presented both the successes and challenges experienced on the aquifer storage and recovery projects in Adelaide and other projects around SA.
Tenix. Leaders in sustainable engineering water solutions. Tenix provides cradle-to-grave engineering services for water infrastructure delivery, including project management, design, construction, commissioning, operations and maintenance. Our in-house design team provides strategic planning, detailed design and commissioning with a specialisation in water, recycling and wastewater treatment plants. As a leader in sustainable engineering water solutions we are the first in Australia to receive an (IS) Infrastructure Sustainability rating for the design of two Wastewater treatment plants in Queensland.
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November 2013 water
New Members AWA welcomes the following new members since the most recent issue of Water Journal
NEW CORPORATE MEMBERS
NEW INDIVIDUAL MEMBERS
QLD Corporate Gold
Hawk Measurement Systems
Murphy Pipe & Civil
NSW M Coleman; P Ferguson;
Concept Environmental Services
TAS Corporate Platinum TasWater
M Nicol; G Ohandja; C Schultz; V Underwood; C Braddock; C Taji; J Vu; J Row; K Dillon; I Gibson; C Welsh; M Oakey; B Hulme; D Hagerty; S Eley; L
John; G Casement; P Haywood; P Pennycuick; M Hancock; Y Gedik; D Davies; L Nicholson; M Wraight QLD R Souter; M McNeil; T Casper; G Hamilton; R Hagen; A Prescott; M Comino; T O’Sullivan; A Harriman; K Jeffries; D Mcaliece; P Larson SA J Cantone; F Adamson; A Gackle; B Hall; S Trumble; D Shah TAS C Dalgleish; A Sneesby; T Watson VIC D Landron; T Overman; R Van Merkestein; W Bishop; G Ferrar; R Appathurai; J
Sunner; B Lewis; R Horsburgh; S Egan; I Zlatin; J Hay; S Cutts; K Steegstra; S Lansdell; V Dickranis WA A Ogden; M Foreman; J-C Carre; J Grima; V Ferritto; J Zou
NEW OVERSEAS MEMBERS B Olson, Shanghai, China
NEW STUDENT MEMBERS QLD O McDonald
AWA EVENTS CALENDAR This list is correct at the time of printing. For up-to-date listings and booking information please check the AWA online events calendar at: www.awa.asn.au/events
November Sun, 03 Nov 2013
WaterAid SA: Football Tournament, Adelaide, SA
Fri, 08 Nov 2013 – Sat, 09 Nov 2013
QWater’13 Conference, Sunshine Coast, QLD
Tue, 12 Nov 2013
Asset Management Technical Meeting, Brisbane, QLD
Wed, 13 Nov 2013
NSW YWP Bootawa Water Treatment Plant Tour, Taree, NSW
Sat, 16 Nov 2013
SA Annual Water Awards Gala Dinner 2013, Adelaide Town Hall, SA
Tue, 19 Nov 2013
VIC Site Tour: Rochester Wastewater Treatment Plant, Bendigo, VIC
Thu, 21 Nov 2013
Unconventional Gas and Water Short Course, Perth, WA
Thu, 21 Nov 2013
VIC Seminar: Catchment Management, Docklands, VIC
Fri, 22 Nov 2013
Galah Debate 2013, Wrest Point, TAS
Fri, 22 Nov 2013
WA Water Awards Gala Dinner, Perth, WA
Tue, 26 Nov 2013
VIC Breakfast Seminar: Women in Water, Melbourne, VIC
Wed, 27 Nov 2013
QLD End of Year Celebration, Brisbane, QLD
Thu, 28 Nov 2013
SA YWP – End of Year Technical Seminar & Networking Event, Adelaide, SA
Thu, 28 Nov 2013
NSW Legends of Water, Sydney, NSW
December Thu, 05 Dec 2013
ACT Awards Presentation and Networking Evening, Canberra, ACT
Thu, 05 Dec 2013
Vic Branch End of Year Celebration, Melbourne, VIC
February Tue, 18 Feb 2014 – Wed, 19 Feb 2014
Master Class: Problems with Pipes – Drinking Water Networks, Sydney, NSW
March Fri, 21 Mar 2014
Water in Mining Conference, Burnie, TAS
April Tue, 29 Apr 2014 – Thu, 01 May 2014
water November 2013
Ozwater’14, Brisbane, QLD
AustrAliAâ€™s internAtionAl wAter conference & exhibition
Take a step up in The water industry Diversify your knowledge Foster business opportunities Build your corporate network Access renowned keynote speakers explore your tech side at the impressive trade expo
registrations open this month www.ozwater.org
Organised & presented bY
ASSET MANAGEMENT: IT’S NOT THAT HARD Ask for help, keep it simple and just get started, advises Matt Gulliver, Asset Manager with TRILITY. intRoduCtion Two words – Asset Management – can send shivers through some people when tasked with this challenge. It’s a massive subject, not clearly defined and somewhat scary to tackle. One definition, suggested by the Institute of Asset Management, is that “Asset Management is the management of (primarily) physical assets (their selection, maintenance, inspection and renewal) [and it] plays a key role in determining the operational performance and profitability of industries that operate assets as part of their core business. Additional categories of assets covered by the scope of this discipline include information, finance, competence and other intangibles insofar as they relate to asset management decisions. “Asset Management is the art and science of making the right decisions and optimising these processes. A common objective is to minimise the whole of life cost of assets, but there may be other critical factors such as risk or business continuity to be considered objectively in this decision-making. This emerging professional discipline deals with the optimal management of physical asset systems and their life cycles. It represents a crossdisciplinary collaboration to achieve best net, sustained value-formoney in the selection, design/acquisition, operations, maintenance and renewal/disposal of physical infrastructure and equipment.” But you are probably still none the wiser as to where to start Asset Management in your business. This article describes TRILITY’s own experience and its experiences with clients, and shares one approach to a daunting subject.
tRility’s eXpeRienCe TRILITY has been providing Asset Management services since its inception more than 20 years ago. Our recent investment in a business-wide change to SAP ERP (enterprise resource planning) and enhancement of the Plant Maintenance module of SAP demonstrates our commitment to staying up to date and having the right tools to do the job.
The focus of this article is to take the reader through the process used when businesses do not know where to begin on their asset management journey.
getting the Right help There are many individuals and companies that offer assistance to commence asset management, so it is important to get the right help. It goes without saying that you need to spend your money wisely and make sure you get the right advice, as changing direction later can be very costly. When looking for assistance, we recommend that you find a company that manages an asset portfolio with similar asset types to yours, and of varying ages. This ensures they are experienced in the management of your types of assets, in all phases of their life. Approaches and deliverables need to have a strong grounding in reality and be developed with empathy for your situation. Strategies and tactics need to be developed from first principles, meaning they can be easily aligned to suit your objectives and service levels. The decision processes used in Asset Management need to take the same approach as other decisions made in your business. These decisions are usually based on risk management and whole-of-life principles, meaning you can be confident that short-term decisions are aligned to optimal long-term outcomes. Quick wins are an essential part of any change management. Therefore, a company that uses its systems and procedures on its own assets can apply them rapidly to your situation and produce results in short timeframes.
the pRoCess The Asset Management Process can be depicted in many different ways. Figure 1 shows a simplified representation of the process for the purpose of this article. These core elements, found in all models, are described in detail in the following sections.
Inputs to the process come from a variety of sources. These We partner with many clients over various mid- to long-term (for a water business) include: contracts, ranging from State Government, to water authorities, to local councils and Documented Execution Inputs Analysis Planning Plans and Delivery developers. Some clients have many Asset Management resources while others have very few. Some have advanced Asset Management thinking, while others do not know where to begin. Some clients are data-rich but information-poor. Some need resources in the field to collect data; and some need specific in-house resources to prepare plans. Figure 1. The Asset management Process.
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asset management • Operations plan • Regulatory requirements • Legislative requirements • Corporate objectives • Corporate risks • Asset replacement history • Asset condition • Asset performance • Capability statements • Metering strategy • Technology replacement • Environmental management plan • Customer and stakeholder expectations • Maintenance management plan • Maintenance and operational costs • Funding sources • Asset replacement cost • Safety issues • Requirements • Risk management plan • Growth forecast • Leakage management plan • Drought management plan • Water quality management plan • Budget constraints • Future regulatory price path • Known issues (Operations & Maintenance Input) While this list seems exhaustive, not all inputs are needed to begin with, and some may not apply. Knowing the company’s business and the environment that it operates in will enable you to ascertain which inputs have the greatest impact on the management of your assets.
Asset Register In order to manage your assets you first need to understand them. Ask: • Do we know the assets we have? • Do we know where they all are? • Are we maintaining all our assets? • Do we have assets with statutory requirements that are not being met? • How would we prove to an auditor that we are maintaining the asset? • Are assets that no longer exist cluttering up the register? • Are job sheets or work orders being issued for assets that no longer exist or have been retired? Not many businesses can confidently answer all these questions.
Feature Article There are no shortcuts; you need to get out there and eyeball all your assets. Take a copy of the asset register from your Computerised Maintenance Management System (CMMS) and the P&IDs (process and instrumentation diagrams) and verify what is actually there. The P&IDs are needed for the criticality analysis, which is conducted later and is usually a desktop exercise. Mark up the asset register with the changes. It is usually best to complete the asset verification with two people, with at least one knowing how the asset is operated and maintained. Create a simple decision tree to identify which assets must be on the register and which don’t need to be recorded. Be sure to cover both the functional location and the equipment sides of the asset register if required by the CMMS. Also, be sure to update the asset register in your CMMS back in the office. Assets that don’t exist should be moved to the graveyard in the system. For new assets, capture the mandatory data to record. Keep the list short at first, as data costs money to collect and needs to cost less than the benefits. Start with the manufacturer, model, replacement cost and installed date. Later, add size, speed, materials of construction and further details. Ensure project staff provide these details, in a timely manner, of the assets they are installing and removing. If possible, have input into the format of their equipment schedules so there is minimal administration work to upload the data they provide. Increased benefits can be achieved by communicating with the maintenance planners and asking them to make any maintenance plans inactive for assets that have been shifted to the graveyard. Also, ensure that all new assets have a maintenance strategy. Completing these tasks will provide confidence that you know what assets you have, where they are, what condition they are in and that the asset register more accurately reflects what is installed in the field.
Criticality Analysis To prioritise the importance of assets to Operations and Maintenance, assign them a criticality rating. Keep the scoring system simple. For example, TRILITY uses a 1–5 scoring system. Complex scoring systems exist that include the size of the system, the social impact, relative location of the asset to creeks and schools, and so on. It’s best to start with a simple system because rating the asset for its importance to Operations and Maintenance will drive the criticality rating accordingly. Clearly define the scoring criteria for each rating, so when different people use the same scoring system, consistent results are achieved. Review the scoring system when conflicting answers emerge, or there is too much group discussion. Aim to increase the scoring system’s clarity and intuitiveness. It may help to use a similar scoring system to the business’s existing OH&S risk assessment matrix. Use a cross-functional team – people in the business who know the importance of the asset and the required service levels. Further benefits can be achieved by letting the maintenance department know that this information is recorded in the CMMS system. Advise them that they can use the criticality analysis to prioritise their work order backlog and forward log.
Asset Condition Score The asset condition score is designed to represent the condition of many different asset types through a single scoring system. These condition scores are recorded on a regular basis and can be trended over time. Assets are generally replaced based on this condition score, rather than their age. A well-maintained and operated asset may live beyond its initial service life and vice versa.
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Feature Article It is strongly recommended that the output of the analysis uses a consistent scoring system, such as risk, to facilitate easier and less subjective planning.
Keep the data current
Great performance comes from a different way of thinking about assets. An asset’s condition into the future can also be predicted using deterioration curves. This gives the asset owner a forecast of future asset replacement and refurbishment requirements for both activities and costs. TRILITY also uses a 1-5 scoring system for asset condition.
Other factors affecting asset service levels When asset condition has been assessed, consider other factors that affect the level of service that the asset provides. These include reliability, water quality, contract compliance, environment, safety and variance to operating and maintenance budgets.
Review asset condition regularly. Be time-savvy by only reviewing those assets with a poor score each year, and remember that some assets may have been replaced in the last year as an unplanned job. If this is the case, update the condition score and check if the asset details are correct. Assets in fair condition should be reviewed approximately every two years. If an asset has a very short service or design life, it will need to be assessed more frequently, while the opposite applies for assets with long service lives.
Asset Risk Score At TRILITY, asset risk is defined as the product of asset criticality and asset condition. It is determined that a critical asset in poor condition receives a higher asset risk score than a non-critical asset in good condition. The asset risk score is used to prioritise the list of replacement and refurbishment projects. A prioritised list will help direct funding to the right areas at the right time. This is particularly effective where one pool of funds covers multiple facilities, so a single prioritised list will ensure the correct distribution of funds across these facilities.
• Reliability Is the asset achieving the expected uptime? This can be measured using mean time between failure, preventative to corrective work order ratio, or overall equipment effectiveness. If this information is not being collected or available from the CMMS, then worst-performing assets can be highlighted by counting corrective work orders or money spent.
Planning is about determining the tactical actions to mitigate risk to an acceptable level. Typically this involves the determination of maintenance plans and asset replacement and refurbishment plans. These plans will include timing of activities, priorities and resources required. Ideally costs should be included at an activity level to input to the annual business planning process.
• Water quality and contract compliance Is the asset performing at a level to assist Operations to meet the contracted levels of service? For example, a chemical dosing system may be reliable and in good condition, but does not have sufficient capacity to dose at high plant flows, which incurs abatements on the contract.
Asset Replacement & Refurbishment Plans
• Environment and safety If the asset is the subject of an environmental or safety notification or non-conformance, consider using that risk score in lieu of the asset risk score. For example, a walkway could be in good condition, but the hatch in the walkway that accesses a confined space creates a high hazard when open for operators accessing the rest of the plant. The source of funding could be the replacement and refurbishment budget. • Variance to budget Compare the asset’s budgeted operating costs to the actual costs, for example power usage or maintenance costs. There may be a business case for the early refurbishment or replacement of the asset.
An activity-based approach is recommended for building up the asset replacement and refurbishment plans. This approach increases the level of transparency in requests for funding and facilitates regular updating. The required replacement and refurbishment activities for each asset are recorded, including estimated or known costs. These activities tend to be repetitive over the longer term, so a frequency can also be included. The installed date and design life information is required to enable these tasks to be correctly scheduled. These activities are filtered by year and sorted by asset risk from highest to lowest. The business’ appetite for risk will determine the cut-off point. This becomes the input to the annual budgeting process and an insight into future costs for inclusion in business plans.
Results – Whole of Life Plans
A full analysis can be undertaken using service, costs, policies, strategies, asset performance and local issues. An explanation of the full process is beyond the scope of this paper. As the analysis process is bedded down, it can be enhanced to include determining the tipping point between maintaining an old asset versus replacing it, or to identify other key drivers in the business.
We build our replacement and refurbishment plans from the bottom up, i.e. from the activity level, including a cost for each activity. Replacement and refurbishment activities tend to be repetitive over the longer term – i.e. a pump needs to be refurbished every 10 years and replaced at 25 years. We enter costs in today’s dollar amounts and use our business planning process to index these costs.
The key to an effective analysis is more about having a balance of inputs as opposed to the sheer number of inputs. Operations should give feedback on operability issues, as well as compliance issues, including abatements. Reliability issues recorded via work order history and worst-performing assets should also be noted to ensure that there is a payback for any funds invested.
We will enter these replacement and refurbishment plans into our CMMS as maintenance plans, in the same system as their monthly, six-monthly and annual servicing requirements. We can then use the CMMS to simulate these planned costs into the future. A warning: don’t create all the work orders, as they will build up in the system. Get the system to simulate the costs without creating the work orders.
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asset management Unplanned costs will also need to be included, in a way ‘planning’ for a level of unplanned activities, i.e. an asset fails before it was expected. Historical records are a good place to start. This simulation will then provide a picture of whole-of-life cost for the asset or group of assets. Consider the level in the asset hierarchy to report whole of life (WOL) costs. It is best to start higher up in the asset hierarchy and then get more granular if required. Start with a whole pump station consisting of a building, a number of pump sets, valves, control system, and so on. This pump station can still be compared to others by using factors such as pump count or capacity or even $/ML pumped. By implementing this, future funding requirements are now based on a transparent, robust and activity-based methodology. This is a big improvement on the typical budget methodologies that use the average of the last three years. It might be flagging some big numbers in the future, but that is all part of managing a portfolio of assets. The business can now plan for this and have the justification to support any requests for changes in the level of funding.
Case Study 1 A client needed to increase the level of transparency on its maintenance budgets submitted to the state water regulator. Maintenance budgets were created using historical costs. A move to risk-based maintenance was suggested, where the level of maintenance is matched to the criticality of the asset. The maintenance strategies to be applied were developed from a failure mode approach and reliability-centred maintenance approach (Failure Mode, Effects and Criticality Analysis (FMECA) and Reliability-Centred Maintenance (RCM) respectively). This change was written into the annual review of the Maintenance Management Plan, and then applied to assets in the field. This involved conducting an asset verification, as many important assets did not exist on the asset register. An asset criticality rating was assigned during a joint workshop with the client, and then the maintenance strategies were developed. A preliminary analysis on the outcomes of the current maintenance plans suggested that some assets were over-maintained, some assets were undermaintained and some assets had the wrong maintenance being carried out. This would be significantly improved with the new maintenance strategies. The failure mode approach allows the maintenance strategy to be reviewed if service levels are not being met. A revised maintenance strategy then allows changes to be made to the maintenance plans in the CMMS. The state water regulator approved the risk-based maintenance approach and the use of a FMECA/RCM approach to developing the maintenance strategies. The new maintenance strategies are currently being created and loaded in the client’s new CMMS.
Case Study 2 On one of our own contracts, the asset criticality rating was used to identify assets that were being over-maintained. Assets in a 100% duty standby configuration with a medium criticality rating were identified to have their mechanical maintenance frequency extended, i.e. serviced less. These identified assets were discussed with operations to ensure that they were suitable for the change. This change represented a 10% saving in planned mechanical maintenance costs and has not resulted in reduced plant availability or asset service life.
Feature Article Case Study 3 Through the joint Asset Management committee, a proposal was made to move towards risk-based maintenance to continuously improve the maintenance of the assets. The current maintenance practices were a mixture of OEM recommendations and corrective actions to service level issues of the past. The maintenance strategies lacked consistency across the asset base. The starting point was the annual review of the Maintenance Management Plan. The risk-based approach to maintenance combined with the failure mode approach and reliability-centred maintenance approach to developing maintenance strategies was then agreed at the joint Asset Management committee and subsequently included in the update of the maintenance management plan. The client was also keen to update its asset register as part of an upcoming upgrade to their CMMS. The asset verification was undertaken jointly by splitting the list of assets and using a common approach, scoring sheet and documentation. The asset criticality rating was assigned during a joint workshop and the maintenance strategies were developed. These were documented in the Tactical Asset Management Plan (TAMP) and agreed changes made to the maintenance plans in the CMMS for the assets. The state water regulator approved the revised Maintenance Management Plan during its annual audit.
Conclusion The points raised in this article are the basics of managing assets. Start with these and do them well. This will provide increased confidence and knowledge of all the assets, their condition and where they are. Better insight into future replacement and refurbishment costs and discussions can be had in the business. As the scoring systems for criticality and condition are created, capture them in a procedure. Start to document the process being used in Asset Management procedures. Create an Asset Management policy that underpins corporate objectives. Ensure decisions made are in line with these corporate objectives. They are all live documents, so do not be too concerned if they are not perfect the first time. Let the Finance and Safety departments know about the new methodology for creating the annual replacement and refurbishment plans. They should appreciate the rigour and transparency in the new process, an improvement on the usual last minute, rushed brainstorm. It will take some time to develop and implement all these basics, depending on how many assets there are, your CMMS and how many resources can be deployed, both people and money. The benefits will flow during this time. WJ Matt Gulliver (email: mgulliver@ trility.com.au) is TRILITY’s Asset Manager, accountable for the Asset Management and Maintenance of all company and client-operated assets. He holds a Master of Business Administration, a Bachelor of Engineering (Mechanical) and is a member of the Asset Management Council of Engineers Australia.
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A UNIFIED APPROACH TO MONITORING AND MANAGING CORROSION OF ASSETS AT EASTERN TREATMENT PLANT The development of a Corrosion Management Manual for buried metallic assets at the ETP. By Ulf Kreher, Ike Solomon, David Solomon and Robert Callant. Melbourne Water Corporation’s Eastern Treatment Plant (ETP) comprises a vast number of buried metallic assets that require an effective corrosion mitigation strategy. Previous strategic decisions on providing cathodic protection of selected buried assets were made without assessing the full impact on the plant or nearby foreign assets. Melbourne Water identified the need for a plant-wide strategy to protect all metallic underground assets from corrosion and stray current effects. This culminated in the development of a Corrosion Management Manual, jointly developed by Melbourne Water and Aurecon. The objective was to provide a step-wise guidance methodology for operators and engineers to make decisions on future corrosion mitigation for existing and new assets. The steps involved were: 1.
Identify key existing buried metallic assets;
Outline issues to be considered when identifying corrosion mitigation strategies based on risks, asset type and process criticality;
Summarise existing cathodic protection systems and discuss lessons learned;
Summarise and explain applicable codes, standards and regulations;
Give guidance on the application of existing Melbourne Water standards;
Develop process flow charts to assist with decision-making processes.
The Manual was developed to be fully applicable to all buried metallic assets including pipes, steel tanks, earthing systems, steel piling and lead shielded cables. Of all the infrastructure types, arguably that relating to water is the most fundamental to life and liveability. Water utilities are facing significant challenges, with ageing infrastructure, population growth, higher community expectations and severe economic pressures in trying to balance water security, quality and customer affordability. Melbourne Water’s Eastern Treatment Plant (ETP) is located in Carrum Downs and was opened in 1975 to treat a large proportion of Melbourne’s sewage (Figure 1). The plant covers more than 1,100 hectares and treats approximately 330 million litres per day or about 40 per cent of Melbourne’s total sewage load. The ETP is, therefore, a vital part of Melbourne’s critical infrastructure, and is required to maintain a high level of service at all times. The plant comprises a large number of buried metallic assets including pipelines and fittings, steel tanks, earthing systems, steel piling and cables.
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Figure 1. Aerial plan of the Eastern Treatment Plant. Most of these assets are crucial to maintaining efficient operation of process systems at the ETP. Key assets include a twometre diameter south-eastern outfall (SEO) steel pipeline, natural gas distribution steel pipelines and 1.8 metre diameter grit and coarse screenings mild steel pipelines. Failure of these assets could lead to potentially serious consequences, due to long lead times required to access, repair and reinstate buried sections of failed pipe. Potential consequences can include prolonged service outages, environmental spills and an inability to maintain effluent discharge limits. Previously, Melbourne Water made strategic decisions to provide cathodic protection to selected individual critical assets, such as the SEO pipeline. These decisions were often made reactively after an incident, without individuals appreciating possible effects upon the plant as a whole and upon nearby surrounding foreign assets. This resulted, on occasion, in costly consequences where newly installed cathodic protection (CP) systems had to be removed from service. In 2012 Melbourne Water, in partnership with Aurecon’s Materials Technology team, embarked on a project to develop a plant-wide
Table 1. Overview of corrosion control strategies. Corrosion control strategy
Corrosion can be prevented if the design reduces the potential to trap moisture or dirt, which will form the electrolyte in the corrosion cell. Good designs should also consider the need for corrosion monitoring through the implementation of such systems during construction or, alternatively, provisions made for future retrofitting.
Material incompatibility is one of the leading causes of corrosion in pipelines. Corrosion can be prevented if corrosion-resistant materials are used or if differing materials are galvanically compatible. Contact between dissimilar metals without isolation must be avoided.
Application of coatings
Coatings can provide an effective barrier between the metal structure and the environment, thus eliminating the onset of corrosion by removing the electric conductor source. A coating can be completely effective as a corrosion deterrent if the material is an effective electrical insulator, can be applied with no breaks and constitutes a perfect film that will retain its integrity over time.
Cathodic protection is an electrochemical method that passivates steel by applying a DC current flow through soil or water to the surface of the metallic structure requiring protection. Thus, it is applicable to buried or immersed structures.
Change of environment
In the hierarchy of control, eliminating the hazard/problem is preferred. Where possible, it is always desirable to avoid direct burying of metallic structures. Other options that can be considered include the placement of pipe fittings and appurtenances in pits, and backfilling of pipe trenches using selected backfill free of rocks, vegetation and chemically-aggressive compounds.
strategy to protect metallic underground assets from corrosion and the effects of stray currents. The Corrosion Management Manual for Buried Metallic Assets had the objective of providing a step-wise guidance methodology for operations personnel and engineers to make decisions on future corrosion mitigation for existing and new assets. The manual was developed to include buried pipelines and appurtenances, steel tanks, earthing systems, steel piling and lead-shielded cables.
Overview of Corrosion Mitigation Strategies Corrosion is an electrochemical process affecting all metallic structures, and can be defined as the destruction or deterioration of a metal due to its reaction with the environment. For corrosion to occur, a corrosion cell must form, whereby the basic elements comprise an anode, cathode and electrolyte and an electric conductor between the anode and cathode. Due to galvanic differences between the anode and cathode, a current flows from the anode to the cathode with metal loss occurring on the anode surface. Corrosion will not occur if one of the basic elements of a corrosion cell is absent, therefore the basic aim of corrosion mitigation strategies is to eliminate or inhibit one or more of these elements. The durability of an asset is influenced by a combination of factors such as its initial design, the corrosion mitigation methods employed, service conditions and design life, with unscheduled plant shutdowns being attributed to corrosion of ageing infrastructure. Asset managers, therefore, need to minimise the risk of unscheduled maintenance to avoid costly failures that can risk plant shutdowns, environmental pollution and even the endangering of life. Therefore, the art of corrosion management is to have the ability to understand the possible exposure to risk, utilising modern day technology assessment tools, good interpretation of data and the ability to develop a strategy to minimise corrosion failures.
The various steps employed in the corrosion management methodology involved: I.
Identify key existing buried metallic assets;
Outline issues to be considered when identifying corrosion mitigation strategies for new/existing assets, and provide guidance to selecting suitable asset management strategies based on corrosion risks, asset type and criticality of asset function;
existing CP (corrosion protection) systems and discuss lessons learned;
and explain the applicable Codes, Standards and Regulations;
guidance to asset owners and custodians on the application of the manual in conjunction with Melbourne Waterâ€™s existing asset management guidelines;
visual aids in the form of process flow charts to assist technical and non-technical personnel with decision-making processes when considering the implementation of new CP or corrosion management systems.
The Manual was developed as a user-friendly guide for Melbourne Water personnel with varying technical skills and experience. The key objective was to provide a simple and effective means of identifying the most common issues relating to corrosion of metallic
The main strategies available to control corrosion are summarised in Table 1.
Methodology Aurecon and Melbourne Water developed a Corrosion Management Manual to provide guidance on the relevant corrosion mitigation strategies to be adopted for two classes of assets: existing buried metallic assets and replacement of existing assets (i.e. new systems). Different assessment and decision-making processes were then applied to the two asset classes.
Figure 2. Tertiary supply pumping station inlet manifold, Eastern Treatment Plant.
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Feature Article structures. From there, a stepwise decision-making tool could be utilised to determine the most appropriate monitoring and remediation measures to be adopted for existing and new assets. The Manual contained the following sections: • Introduction and objectives of the Manual; • Overview of corrosion mitigation strategies; • Selection framework for existing and new buried metallic assets; • Register of existing buried metallic assets; • Risk and criticality assessment of existing assets; • Typical corrosion issues expected; • Overview of applicable standards and codes; • Overview of testing and monitoring techniques for buried metallic pipelines; • Design considerations for CP systems;
Corrosion Mitigation Strategies for Existing and New Assets For existing assets, a three-tier hierarchy was applied to manage the risk of corrosion and structural deterioration, namely: • Prevention/mitigation of corrosion; • Monitoring of corrosion or corrosion risk; • Replacement of asset. Prevention of corrosion is obviously the most desirable option since it poses the least risk and disruption to ongoing operations of the plant due to unscheduled shutdown and maintenance. Monitoring corrosion or risk of corrosion is an essential aspect to assess the likelihood of asset failure, and is required for all classes of assets with varying conditions and inherent corrosion management systems. Assets with a higher criticality rating require a more rigorous and extensive monitoring regime, examples of which include: • Close Interval Potential Survey (CIPS);
• Reference drawings and survey information.
• Direct Current Voltage Gradient (DCVG) Coating Defect Survey;
Risk Assessment of Existing Assets
• Excavating the buried asset and visually inspecting the surface coating condition and extent of metal loss;
An important precursor to the development of the Corrosion Management Manual was to identify and document the condition • Potential surveys; of all existing buried metallic assets Table 2. Details and criticality rating of buried metallic assets at the Eastern Treatment Plant. at the ETP, and subsequently assign a Criticality rating. Over a Coating CP system Criticality Asset description Material four-month period, the Melbourne condition installed? rating Water and Aurecon team undertook Earthing system Copper n/a No 5 detailed desktop studies of available Grit & coarse screen pipework Mild steel New Yes 5 information for all existing buried metallic pipelines, as well as earthing Possibly Natural gas pipes Mild steel No 5 systems, to assess key aspects such deteriorated as the coating condition, electrical Mild steel, Filtered chlorinated water (3W) pipes Deteriorated No 5 continuity, electrical isolation and Copper presence of CP systems. South Eastern Outfall pipeline Mild steel Deteriorated Yes 5 Once all major assets were Tertiary Treatment Plant – Large Mild steel New Yes 5 identified, a qualitative risk assessment diameter pipework approach was applied by assessing Tertiary Treatment Plant – Medium to the likelihood and consequence of Mild steel New No 5 small diameter pipework failure of each asset class. A Criticality rating was then applied to each of the assets to categorise them into different priority classes, with a score of 1 representing ‘Low’ priority assets and 5 representing ‘Extremely High’ priority assets. This criticality classification allowed Melbourne Water to focus its attention and operating expenditure on assets that served the most critical functions at the ETP. This asset register also provided a baseline reference to Melbourne Water’s Asset Planning, Operations and Maintenance teams by ensuring that all of the important information relating to the corrosion protection systems of buried metallic assets was recorded in a single database. Table 2 provides a summary of the risk assessment carried out for the buried metallic assets at the ETP, arranged in order of process criticality.
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Digester sludge pipework
Mild steel, Brute
Return Activated Sludge pipework
Final effluent sample point pipework
Secondary scum pipework
Potable water (1W) pipework
Sanitary drain pipework
Tank drainage pipework
Pump drainage pipework
Cast iron/ Ductile iron
Aeration air pipework
Chilled water flow pipework
Chilled water return pipework
Heat reservoir flow pipework
Heat reservoir supply pipework
Class C final effluent (4W) pipework
Ductile iron/ HDPE
Waste heat cooling water return pipework
asset management • Insulating flange testing; • Routine CP monitoring; • Stray current interference testing; • Soil resistivity surveys; • Groundwater monitoring. A last resort option would be the replacement of the failed asset and adopting sound design principles that take into account corrosion mitigation techniques. A strategic stepwise approach was developed in Figure 3. Stepwise decision guide for conjunction identifying a suitable corrosion management strategy for existing assets. with key Melbourne Water stakeholders and Aurecon personnel to identify a suitable corrosion management strategy for existing assets. An extract of the process flow chart for the decision guide is shown in Figure 3. A similar process flow chart was developed for the identification of suitable strategies for new buried metallic assets. Part of the work involved in-depth investigations into the likely corrosion mechanisms that would occur at the ETP. These mechanisms represented the majority of causes leading to premature deterioration of buried metallic assets. In order to develop sound corrosion mitigation strategies, it was crucial to identify the leading causes of asset failure and tailor an approach to suit the specific operating environments in which the assets were installed. Following completion of the Manual, a workshop was held with all stakeholders to outline the use of the Manual and ensure that it would be readily integrated into the extant asset management strategy.
Case Study The methodology and framework prescribed in the Corrosion Management Manual was applied to a number of critical assets at the ETP including the SEO pipeline, which runs from the Outfall Pumping Station (OPS) located in the plant to the Boags Rock Outfall. The purpose of this pipeline is to discharge tertiary-treated effluent from the ETP to Bass Strait. The main objective of the study was to apply a suitable strategy and provide recommendations for corrosion management of this critical asset. The stepwise decision guide, shown in Figure 3, was referred to when assessing suitable asset management pathways and determining the appropriate strategy. The study recommended the following actions: • Investigate options to establish electrical isolation of the SEO pipeline;
Feature Article • Engage a cathodic protection (CP) specialist to design the CP system for the pipeline, including interference mitigation, and install the CP system; • Establish a testing regime involving: -- Ongoing monitoring of CP system performance and functioning of insulating flanges -- Performance assessment of a Close Interval Protection Survey (CIPS) -- Performance assessment of a Direct Current Voltage Gradient (DCVG) survey.
Conclusion The development of a Corrosion Management Manual for buried metallic assets at the ETP has enabled Melbourne Water to adopt a unified approach to monitoring and managing corrosion issues of its assets. In many respects, the manual represents over 50 years of accumulated corrosion mitigation knowledge that has been successfully applied to Melbourne Water’s buried water pipelines and steel water tanks. Above all, it offers valuable insight into the condition of existing assets and presents a proactive and structured approach to developing corrosion mitigation strategies for buried metallic assets, which even inexperienced personnel can follow. Future engineers joining the organisation at the ETP will have ready access to a wealth of documented historical information on the buried assets that would otherwise have been lost as senior, experienced staff retire. WJ
ABOUT THE AUTHORS Ulf Kreher (email: Ulf.Kreher@aurecongroup. com) is a Senior Materials Technologist and leads Aurecon’s Materials Technology Group. He holds a PhD in Chemistry, and is an ACA accredited Corrosion Technologist and certified as NACE Cathodic Protection Specialist. Ike Solomon (email: Ike.Solomon@ aurecongroup.com) is a Principal Materials Engineer at Aurecon in the Materials Technology Group. He has 36 years’ experience in materials and corrosion control technologies, particularly cathodic protection and remediation of rising salt damp. David Solomon (email: David.Solomon@ aurecongroup.com) is a Materials Technologist at Aurecon’s Materials Technology Group. He has over six years’ experience in engineering and corrosion surveys. He received his qualification as a Cathodic Protection Tester (CP2) from NACE International in 2012. Robert Callant (email: Robert.Callant@ melbournewater.com.au) is Area Leader at Melbourne Water’s Asset Planning Group. He holds a Graduate Diploma in Technology Management, a Bachelor of Arts, an Associate Degree in Applied Science and is an Australasian Corrosion Association (ACA) accredited Corrosion Technologist.
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OPPORTUNISTIC ASSESSMENT OF BURIED PIPELINES Information to guide the assessment and data collection of buried pipelines as part of a water utilityâ€™s maintenance and minor works program. By Alf Grigg and Geoff Hales. Opportunistically assessing buried pipelines during pipeline maintenance and minor works activities is an efficient and effective means of sourcing information on the pipelines to assist with risk management and renewal and maintenance programming. This article provides an overview of the key principles in establishing an efficient and effective opportunistic assessment process for buried water and wastewater pipelines. Effective management of assets relies on a good understanding of those assets, including their condition and risk of failure. Due to their inaccessibility, obtaining such information for buried pipelines can be significantly difficult and costly. An opportunity to efficiently source such information for buried pipelines presents itself at the time the pipelines have been exposed and isolated for maintenance and minor works purposes (Figure 1). To ensure that the most important information is collected and the effort and resources used in collecting this are not in vain, a systematic process is required to be implemented. The authors have recently developed an Opportunistic Pipeline Condition Assessment and Data Collection Guide for Unitywater. The guide identifies the type of information to collect, including the use of simple in-situ tests, and sampling for further off-site examination and laboratory testing.
Background Discussion Every pipeline failure, except where solely due to damage by a third party, represents a statement of the condition of a pipeline. All failures demand a maintenance response, even if the pipeline asset requires no more than the installation of a sealing band to stop a leak from a perforation or circumferential crack. Evaluation of the failure, and the condition of the exposed section of intact pipe, adds to the knowledge base of the particular pipeline asset.
Figure 1. An opportunity for pipe assessment. A 300mm DN MSCL pipeline, ready for repair using repair bands. The exposed section of pipe displayed externally corroded sockets.
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Many failures follow well-documented patterns. The failure, therefore, adds to that pattern and strengthens the case for replacement. Failures of pipeline assets with no prior history of failures represents an opportunity to assess a potentially emerging failure mechanism, some of which are slow and others of which represent the leading edge of a systemic failure pattern. Maintenance and construction crews often yield pipe shards from site activities. Such shards provide a snapshot in time of the condition of the particular pipeline. That knowledge, when added to a dataset that has been progressively accumulated over time, may yield a timely warning that the pipeline is approaching the end of its useful life. An example is a 300 AC pipeline constructed in coastal conditions in the early 1960s, which is the subject of planned cut-in works. A simple phenolphthalein indicator test on the recovered shard can reveal the extent of the progressive external pipe wall section loss from acidic groundwater conditions (Figure 2). A gouge test would reveal a similar story to the phenolphthalein test. Given a pipe length of 15km, advanced knowledge of the residual life remaining will be vital for advanced financial planning. Sourcing information from field crews is very valuable. Often they are quite familiar with the pipeline and environment and can provide good insight into the issues, so decisions can often be made without the need for further investigation. Providing a systematic process to communicate their observations and recommendations is important.
Figure 2. The result of phenolphthalein being applied to the ends of an AC pipe shard. The pink colour indicates the presence of calcium in the pipe wall media.
Table 1. Types of information to be collected and potential utilisation. Information
Updated details on asset (e.g. pipe material, size, protective lining etc)
• Multiple purposes, such as planning, maintenance etc
Failure data (being type and cause of failure)
• Assist any follow-up actions from a pipe failure (e.g. damage claims against utility or a third party that may have caused damage) • Identify any significant failure trends that need to be addressed
Pipe condition (from in-situ visual assessment and testing (optional))
• Understand extent of deterioration of pipeline section • Estimate remaining useful life of pipeline section • Improve understanding of rate of deterioration of different pipeline cohorts • Estimate likelihood of further failure of pipeline section, and in combination with failure consequence information (refer below), determine risk of failure
Consequence of failure (from site assessment)
• In combination with condition information (refer above), determine risk of failure of pipeline section
• For consideration when management/planners are considering proposed works
Sustainable Assessment With the pressure to control water prices, water utilities need to optimise their operating activities and expenditure. Therefore, work activities in the field need to be completed efficiently. There can be a reluctance to spend further time collecting additional information. It has been commented that ‘every additional field required to be completed in a form as part of a maintenance or minor works activity could end up costing thousands of dollars’. An alternative option is to undertake the required assessment when the information is required. However, as renewal and maintenance planning are regular activities, up-to-date information is generally required on an ongoing basis. Sourcing the information separate to maintenance and minor works activities will require a significantly higher level of resources, including funds. For instance, a pipeline will need to be specially exposed and backfilled just to assess it and source the required information. In lieu of recovering a shard that would usually be generated from pipe repairs (except for MSCL pipe, which can commonly be repaired using repair bands) and cut-ins, a coupon would be required to be extracted and examined. For AC pipelines, this could be problematic if the pipe wall is found to be soft. It is considered the most efficient strategy is to (i) assess the pipes opportunistically during maintenance and minor works activities initiated for other purposes (e.g. pipe repairs and cut-ins) to an extent that is within the capacity of the field workers; and (ii) separately undertake further more detailed assessments on an as-required basis. Efficiencies of opportunistic assessments can be improved by:
cause of failure) than as ‘open text’. This allows the information to be quickly recorded and be more readily analysed. Some ‘open text’ will always be required to be recorded to capture unusual observations, to clarify why a critical option was selected, or to elaborate on a recommended action.
In-situ Testing In some cases, additional in-situ testing may be appropriate to further understand the condition of a pipe and its remaining life. Consideration needs to be given to factors such as pipeline type, criticality and material, and the type and cause of failure if such has occurred.
Other factors include whether the pipeline has been identified previously as requiring further condition information for risk management or cohort assessment purposes. This would need to be communicated in a way such that field crews would know whether that applies to a pipeline they are working on. An example of a typical in-situ test and its application is provided as follows: A circumferential break in an AC pipeline is commonly caused by ground movement or weakening of the pipe wall. The exact cause, and the condition and remaining life of the pipe, can be difficult to assess visually. A gouge test, in which the pipe surface is gouged with a hardened tip, can be used to assess the extent to which the pipe media has been softened by corrosion/conversion processes. Note: The test may not be required if the pipe wall was observed to be fully degraded/softened when using a chain-cutter to cut the pipe as part of the repair process. Another simple in-situ test is the hammer test, which can be used to reveal the depth of corrosion/erosion of ferrous and concrete pipe walls. A ferrous pipe shard can also be examined for corrosion around perforations following removal of coatings and cleaning the pipe metal surface. CCTV inspections, where undertaken to assess failures in gravity sewer pipelines, can help inform the assessment of pipe condition and failure type.
In selecting what information is to be collected, the major consideration should be why it is required and how it will be utilised. Examples are provided in Table 1.
In some cases, samples should be recovered for further off-site detailed examination and/or laboratory testing. Consideration needs to be given to the same factors as for in-situ testing, with an aim to limit unnecessary recovery of samples. It is not uncommon to hear about situations where a stockpile of pipe shards, that have never been examined or tested, has built up in a depot over several years and eventually had to be discarded. Even with a good process in place, not all recovered and stored samples will undergo further assessment, as a more stringent criterion for testing etc, as discussed in the following section, will be required. But hopefully, such a process will limit the number of samples that end up not being required.
It is preferable to have information provided as a selection of pre-defined options (e.g. third-party break, internal corrosion etc. for
Sampling is only proposed to be undertaken where ‘practical’ and safe to complete. Unless there are special requirements to cut
• Having the information digitally collected (using mobile devices) and transferred/uploaded to the required location (e.g. a Computerised Asset Management System); and • Limiting requirements on assessments to be undertaken, data to be collected, and samples to be recovered, in the field.
General Information to Collect
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Feature Article out a sample from a specific pipeline, it is only proposed to recover samples from shards (off-cuts) arising from the work activity. An example of where it may be prudent to recover a sample is provided as follows: A failure of a ductile iron pipeline that is not due to damage from a third-party, has not been sampled in the same location over the past year, and in which greater than 1mm depth of corrosion/erosion has been observed after the hammer test. The purpose of the sample would be to allow further examination, after ‘grit-blasting’, to gain a better understanding of the pipe condition and remaining life. The recovery, transport and storage of pipe samples needs to be well managed to address associated safety risks (particularly with AC pipes), and ensure any results from further examination and testing can be readily correlated with and recorded against the relevant section of pipeline. Samples selected for dispatch to testing laboratories must be adequately labelled, stored and packaged to ensure safe storage and transport, and to ensure that hazardous materials such as AC pipe do not pose health risks to any person in the chain of the transport and delivery process. Labelling of all pipes must comply with current prescribed procedures for chain of custody of hazardous waste. Compliant labelling ensures that the receiving laboratory is notified of the contents of a package, and can safely handle and store a sample prior to laboratory testing.
Off-Site Sample Examination and Testing Whether to further examine and test a pipe sample needs to be decided on a case-by-case basis. Once again, the factors listed for in-situ testing need to be considered, in conjunction with the following: • The availability of adequate existing information on the subject pipeline or cohort; and • The cost of, and type of information that can be obtained from, further examination/testing. The general purpose of the examination/testing should be to confirm the mode of failure if the sample incorporates the part of the pipe that failed, assess the condition of the sample and provide an estimated remaining life of the pipe. The latter will require additional information, such as details on the operating
environment (e.g. hydraulic head for pressure mains), and chemical data on (or a representative sample of) the surrounding ground and the fluid being transferred through the pipeline. There are some relatively simple and low-cost methods, such as detailed examination of ferrous pipes after grit-blast cleaning (Figure 3), and the phenolphthalein indicator test for calcium-based and internal cement mortar lining. The types of more detailed examination and testing methods are numerous, varying based on the pipe material and class and the standard the pipe was constructed to. For this reason, and the improvements being made to pipe testing, the selection of method should be made in consultation with the service provider.
Challenges Some of the key challenges with an opportunistic pipeline assessment program are discussed as follows: Work Health and Safety All work needs to be completed in accordance with appropriate Work Health and Safety standards. There are significant risks associated with AC, high pressure and deep pipelines, and sections of pipelines on the side of, running parallel in, or across roads. Data Quality The quality of the outcomes from the assessment program is highly dependent on the quality of the data collected. Two key strategies to encourage the collection of good data are: • Demonstrate the reason for the assessment, and how the data collected is being used; and • Regularly provide summaries of data collected to those responsible for the assessments, and seek their input on trends etc.
Conclusion Opportunistic assessment of buried pipelines can be a very efficient and effective way to get a better understanding of the buried pipeline network, including the condition and risk of failure of various pipelines. A systematic process for the assessments needs to be developed and implemented to maximise the cost benefit.
Acknowledgements The Authors would like to acknowledge the input of Unitywater staff, who not only helped with the development of the guide for Unitywater, but also informed some of the principles discussed in this article. WJ
The Authors Alf Grigg (email: firstname.lastname@example.org) is Director of Alf Grigg & Associates, a regionally based consultancy firm that specialises in condition evaluation, failure analysis, and residual life predictions for water, sewer and stormwater assets.
Figure 3. Recovered Ductile Iron pipe shard, displaying the effect of garnet-grit blasting that reveals the actual iron matrix surface and the extent of pipe wall loss.
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Geoff Hales (email: email@example.com) is Director of Barnewall Resources Pty Ltd, a small Queensland consultancy firm providing asset management services, particularly to the water industry. He has assisted several Queensland Water Utilities with the development of opportunistic asset assessment processes and guidelines.
ENTERPRISE RISK MANAGEMENT IN ASSET-INTENSIVE ORGANISATIONS Mark Gibbs and Mike Stoke discuss the findings of a recent global survey on risk management conducted by consulting group KPMG. The world-renowned social scientist Ulrich Beck has described late modern society as the ‘risk society’, as a result of our global pre-occupation with minimising personal and institutional risk, and our unrelenting individual and collective efforts to transfer risk onto others where possible. Consistent with this observation, the formal management of risks within organisations has escalated from an ad hoc but sensible thing to do, to an externally mandated compliance-driven function and a regular feature of board and executive agendas. The number, scale and complexity of risks that need to be managed seems to increase year on year and this is probably a direct consequence of our individual efforts to de-risk our personal, professional and organisational lives, often by transferring the risk to someone else. If risk is transferred to someone less able to manage it, they must hedge or provide greater contingency, so the overall cost of risk management continues to increase, impacting eventually on productivity. The most efficient outcome will most likely occur when specific risks are managed by the organisation or person most able to do so, because the overall contingency and, therefore, cost will then be a minimum. However, implementing this in complex organisations continues to be problematic. In the case of asset-intensive organisations such as water utilities, an under-investment in essential infrastructure is equivalent to a transfer of risk to consumers (the escalating risk of infrastructure failure will force consumers to find a generally higher priced alternative). Consumers of services provided via infrastructure are likely to be among those stakeholders least able to manage the risk efficiently.
Challenges Faced By Asset-Rich Organisations Asset-intensive organisations that utilise both individual largescale, long-lived assets and complicated networks of smaller assets to deliver services can find it especially challenging from a risk management perspective, and our experience suggests that the management of risks in asset-intensive organisations such as water utilities is somewhat patchy. This is consistent with a recent global survey conducted by KPMG titled “Expectations of Risk Management Outpacing Capabilities – It’s Time for Action”, which found that: • The risk management challenges facing many organisations are running ahead of the organisation’s ability to manage; • Many C-level (CEO, CFO, COO) executives feel that their organisations are unable to manage risks in a holistic, internally consistent and, therefore, optimal manner; • Few of the C-level executives surveyed felt that their organisations had a clear understanding of the enterprise-wide appetite for risk.
It is likely that some, if not all, of the observations revealed by the survey will resonate with many leaders in asset-intensive organisations such as water utilities, many of whom are struggling to increase the useful life of major assets. The findings from this survey can, therefore, be used as a call to arms, especially for those that are floundering to manage the ever-increasing lists of risks identified on risk registers, along with the risks that are not listed, but which should be identified and actively managed. What should be done about this? It is convenient to think of risk management in terms of the what, when and how: what risks need to be actively managed, when they should be managed; and how they should be managed. Most corporate risk managers and leaders of organisational business units recognise that they face an increasing number and more complex array of risks, demonstrated by an ever-expanding risk register. Some of these are low-likelihood but high-consequence ‘sleeper’ risks, while others are more mundane, high-occurrence but low-consequence risks. New risks arise from factors such as changes to the regulatory environment, or the untimely occurrence of natural hazards, which are in some cases exacerbated by climate change. Risks do get removed from risk registers as action is taken to mitigate them, but as identified in the survey, the rate of removal of risks from risk registers is commonly slower than the rate at which new risks appear or are recognised. Risk management can often appear to be a losing battle. To actively manage all possible risks, they need to be identified and then prioritised for management – not all risks are significant enough to warrant special treatment. The process of identifying possible risks is generally well understood from both a corporate risk management perspective and from within business units. This generally involves workshopping potential risks and capturing them on a risk register. However, individual business units are generally subject to different incentives, which often do not map perfectly onto the drivers or incentives placed upon corporate leadership.
Resolving Inconsistencies It is common for business units to have a tailored perspective of their contribution to corporate objectives and, therefore, to have too constrained a view on the significance of ‘their’ risks. Hence it is not uncommon for different weightings to be placed on similar risks by different parts of organisations. One of the common indicators of this problem is the range of policies adopted by the Board: there will be policies to cover procurement and staff, for example, but often not a formal policy covering the management of critical infrastructure, which is where much of the risk lies in water utilities. One approach to solving such inconsistency is to attempt to centrally manage all risks. However, this contravenes the principle of subsidiarity – that risks are often best managed at the source,
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Feature article which will often be the business units. Another approach is to set enterprise-wide definitions of consequence and likelihood, and this is becoming increasingly common. However, even with enterprisewide definitions in place, it is still not unusual to see the same risk weighted differently by different business units. This problem can be solved by centralised or corporate arbitration, but at the cost of disengagement of individual business units. This is especially the case with regards to the management of assets and networks of assets, because there is still a widespread view that asset management is primarily and solely about managing assets. By contrast, best practice asset management focuses on the management of services delivered by assets, rather than the assets themselves (and this is articulated in the forthcoming ISO 55000 series). Risks to service levels need to be managed, rather than risks to assets themselves, which therefore requires a focus on those assets that are critical to service provision. The key trade-off required is, therefore, not between costs/funds/resources and asset condition, but between costs/funds/resources, level of service, and risk to those levels of service. Reducing funding on assets can result in both a reduction in level of service, and an increase in organisational risk. The relationship between these three concepts can be cryptic, however, and not obvious. The implication is that these three key variables need to be measured in an internally consistent manner so that they can be directly compared. What we generally find is that expenditure is measured, level of service is sometimes measured, but risk to not meeting the required level of service is not.
Tsunami storm barrier in Tsugaru, Japan – an example of managing a high-consequence/low-likelihood risk category. a practice that is relatively uncommon, partly as a result of the lack of a time domain in most risk tables. This is further complicated by relationships between historical events, which are commonly used as a proxy for future risk. By making this connection, we are assuming the past represents the future. In doing so we are managing ourselves in a way that implicitly assumes that the past is a perfect representation of the future, which cannot always be the case, especially with regards to climate change and future economic conditions. It is the difference between the past and future where the most risk lies.
When and hOW tO Manage RisKs
A more insidious problem when using risk tables (tables of consequence and likelihood) to manage risk is that the majority of risks fall into the ‘medium’ risk categories in the middle part of the table. This means that risk managers feel that they have to prioritise or choose between allocating resources to managing, for example, a devastating tsunami or climate-change mediated major weather event (high consequence/low likelihood), or the leakage of a rural trunk main that occurs annually but impacts only a small number of residents (high-likelihood/low-consequence).
When should risks be managed or, more importantly, when should risk management be practiced? Surveys like KPMG’s consistently highlight the patchiness around risk management within both medium-sized and large organisations. As highlighted, it is common practice to allocate risk management responsibilities unevenly throughout corporate administrative functions (for example, a dedicated risk manager) and diffusely within business units. Similarly, risk management is commonly a mixture of processes and procedures and culture.
In the case of the rare extreme natural hazards, our minds are ideally suited to misinterpreting the risks of these rare events, sometimes described as ‘Black Swan’ events, a term coined by Lebanese-American essayist, scholar and statistician, Nassim Taleb.
The answer to when to manage risks is simple: constantly and relentlessly. When considering how to manage risks, it is clear that all staff within organisations cannot simply be redirected towards exclusively managing risks. However, like health and safety risk management, all forms of risk management need to be embedded in the culture of the organisation. Like health and safety, it will also take several decades for such a culture to be fully embedded. While we have become very effective in our personal lives at transferring risk away from ourselves, at an organisational level we are often less effective.
RisK liFesPan Managing these supposedly equal risks can be addressed through a better understanding of the organisation risk appetite, as described later. However, the other factor to keep in mind is the lifespan of the risk. In the examples used above (a rare natural hazard or a low-level leak), the rare event will have the same long-term likelihood of occurrence every year (although climate change may increase the average annual likelihood), but the pipe will continue to downgrade over a timescale of years. Hence the risk profile of the pipe changes more rapidly over time, while the long-term average of the rare event remains more consistent often over decadal timescales. This does not mean that the long-term risks can be ignored, or that an extreme event will not occur anytime soon, as the long-term return periods of natural events only describe the probability of such an event occurring within any particular year – they still actually happen. It also does not mean that the trunk repair is necessarily prioritised over the rare events, but it does highlight the need to capture the lifespan of risks when identifying and assessing risks,
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This brings us back to the all-important how. Considering the fundamentals, risk management at some stage requires the allocation of resources. Most asset-intensive organisations have clear processes for allocating resources. However, these commonly only implicitly map onto risk at best. For example, it is common within asset-intensive organisations to develop rolling and annual capital investments plans, describing CAPEX and OPEX expenditure. It is also common to have each business unit develop these independently, for aggregation at corporate level. It is also common to use economic cost-benefit type analyses to prioritise this expenditure. Cost-benefit approaches reveal whether the general benefits exceed the costs. However, the assessed benefits rarely explicitly quantify the risk reduced. These sorts of
asset management analyses, therefore, rarely explicitly map onto risk reduction and, importantly, the efficiency of risk reduction. Hence the quantification of risk reduced is often lost within these processes. Keeping track of the risk reduced and cost of reducing risk can only be achieved if the risk is quantified consistently across the organisation. This is not as obvious as it seems. For example, it is common to see proposals for CAPEX or OPEX in relation to a specified asset, but it is rare to be presented with an analysis that shows the full costed risk of loss of service of the plant (often an opportunity cost), quantified in an internally consistent manner. If the expenditure is approved, the organisational risk reduced and the return on investment of risk mitigation need to be quantified and tracked. Only by assessing this information can a true enterprise-wide risk management approach be implemented, and assessments against risk reduction be determined. It is common practice to prioritise resource requests and to fund the list down to the point where a pre-determined funding allocation is met. Once again this leaves no way of identifying the residual risk being carried by the organisation, unless that risk is explicitly quantified and tracked. More progressive organisations seek to determine the organisation’s appetite or tolerance for risk, which is informed by the assessed cost to manage each risk. Acceptable risk and, hence, risk appetite should be linked to levels of service, both target and achieved, not to asset condition alone. The critical trade-off to be managed is the three-way trade-off between level of service, costs and risk. This is a far more robust and defensible approach, and one that we have found Boards can understand and relate to.
Feature article For example, after quantifying the consequences and corresponding annually averaged damages from so-called Black Swan rare events and the costs to mitigate these risks, it is conceivable that some organisations might not have the appetite to actively (self) manage them, and choose instead to transfer them via a form of insurance (assuming that this option is available). However, such a decision would be risk-informed, and C-level members of the organisations and the Board would be aware of the real and quantified residual risk being carried, a position that many assetintensive organisations presently cannot claim. For many organisations there is a large gap between the current approach of managing risk through basic procedures and policies informed by risk tables, and an informed and enlightened risk management standard and set of procedures that makes decisions based on a comparison of the costs and benefits of risk mitigation and tracks return on investment in risk mitigation actions. However, in the interest of continuing business improvement and best-practice risk management and accountability, the pathway forward is clear. WJ
the aUthORs mark Gibbs (email: mark. firstname.lastname@example.org) is the Director for Infrastructure and Environmental Risk Management for AECOM ANZ. mike Stoke (email: Mike.Stoke@ aecom.com) is a Technical Director at AECOM in Brisbane.
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Control System Modelling for the Integration of Perth’s Second Desalination Plant Eelko Van Der Vaart and Faris Hernich discuss the value of control system modelling from early design through to commissioning. Abstract
This article describes the system modelling approach used in the design and commissioning of a control system for Ravenswood Pump Station. The control system is a state-of-the-art system that allows a remote operator in the Water Corporation’s Operations Centre to manage water transfers to Perth in the most efficient way. The control system automatically adjusts the speed of the pumps when system conditions change, to maintain the desired transfer rates.
The Southern System is supplied from the Stirling Dam, the new Southern Seawater Desalination Plant via Harvey Summit Tank and from Samson Pipehead (Figure 1). The major artery of the system – the Stirling Trunk Main – connects Stirling Dam in the south with Tamworth Reservoir in the north and is a DN1400 MSCL pipeline with a length of 108km.
A purpose-built model of the water transfer system was used to simulate the behaviour of the control system in response to changes in the pipeline system. In the early design stages, the model was used to evaluate a number of design options for the control system. One option was selected and developed further in the following stages of design. The model played a further role during the commissioning of the Southern Seawater Desalination Plant Integration Works by simulating commissioning tests before conducting the tests on the live system. This greatly reduced the risks associated with the real-life testing.
Introduction Stage 1 of Perth’s second desalination plant, the Southern Seawater Desalination Plant (SSDP), has recently been constructed and commissioned. Substantial upgrades to the existing water transfer system, the Southern System, were required to deliver an additional 166 ML/d into Perth’s Integrated Water Supply Scheme (IWSS) (IPB, 2009). In order to maximise transfers of desalinated water, as well as water from existing sources, a new pump station has been constructed in Ravenswood, approximately two-thirds of the way along a major existing transfer main. The new 12MW Ravenswood Pump Station is located at the intersection of two major pipelines and consists of two separate banks of variable speed pumps that can simultaneously deliver water in two separate directions. The two banks of variable speed pumps have been equipped with a control system to provide a remote operator with the means to control the flow rate of each bank via the Supervisory Control and Data Acquisition (SCADA) system. The control system is installed locally and controls the flow rates of the banks using closed loop feedback control. This allows the remote operator in the Water Corporation’s Operations Centre to manage water transfers to Perth in the most efficient way. The introduction of feedback control in pump stations gives rise to complex dynamic behaviour, because the control systems are continuously adjusting the speed of the pumps in response to changing conditions in the pipeline system. Since the application of feedback control of flow rates and pressures in water transfer systems is a relatively new development, control system modelling was used from the early design stages to inform and guide the design process for Ravenswood Pump Station’s control system.
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Figure 1. The Southern System.
Feature Article At the start of the design process, a System Modelling Guiding Group was formed to guide the system modelling for Ravenswood Pump Station. The group consisted of a well-rounded range of disciplines and included an asset capability manager, system planners and a pump station design manager from the Water Corporation, as well as a water systems consultant (from GHD at the time).
Figure 2. Hydraulic model – Ravenswood Pump Station. When the total source production is low, water is transferred to Tamworth Reservoir, North Mandurah Tank and Caddadup Tank by gravity. When the total source production is high, Ravenswood Pump Station boosts water transfers with two banks of pumps, the Tamworth Bank and the Dandalup Bank. The preferred transfer route for the source water is north via Tamworth Reservoir using the Tamworth Bank. When the total source production exceeds the transfer capacity of the Tamworth System, the Dandalup Bank of Ravenswood Pump Station is started. This bank then boosts the excess source production to either Serpentine Pipehead for transfer to Perth or to North Dandalup Dam for seasonal storage. Ravenswood Pump Station Ravenswood Pump Station consists of two separate pump banks, the Tamworth Bank and the Dandalup Bank, that operate as two separate pump stations (Figure 2). The Dandalup and Tamworth Banks have each been configured with three variable speed pump sets. The Tamworth Bank operates with relatively high flow rates between 125 ML/d and 265 ML/d and low heads up to 120m. The Dandalup Bank operates with relatively low flow rates between 30 ML/d and 130 ML/d and high heads up to 225m. The maximum flow rate achievable for the Ravenswood Pump Station with both banks in operation is 285 ML/d, which is governed by the residual head at the suction side of Ravenswood Pump Station and hence the Net Positive Suction Head (NPSH) available to the pumps.
Methodology The Southern System is relatively complex, with a number of connected sources and supply points, as well as supply directly to reticulation systems in Mandurah and Caddadup. In designing the control system for Ravenswood Pump Station, both the current and the future operation of the system had to be taken into account. Because the future operation of the Southern System depended on the design of Ravenswood Pump Station’s control system, the design process was required to be iterative. It was also important to involve key stakeholders to ensure the final control system design would meet the Water Corporation’s operational requirements.
In order to simulate the dynamic behaviour of the Southern System with the new Ravenswood Pump Station, a purposebuilt model was created in hydrodynamic simulation package WANDA (Deltares, 2008). WANDA is one of a small number of software packages that have the ability to simulate the dynamic behaviour of control systems in pipe networks. The WANDA model created was based on Water Corporation WATSYS models of the Southern System and the preliminary mechanical design of Ravenswood Pump Station (Figure 2). In WANDA, control behaviour is modelled by measuring hydraulic parameters in the hydraulic model and using these as inputs to control logic components such as proportional-integral controllers (Figure 3). The control logic components calculate control actions, such as a change in pump speed, based on the control parameters (e.g. proportional gain, integral time constant) and the difference (error) between the measured hydraulic parameter and the setpoint for the parameter. The output of the control components is then fed back into the hydraulic model to change pump speeds or valve positions. Early design In the early design stage, the focus of the system modelling was on developing an understanding of the Southern System’s dynamic behaviour and testing a number of control strategies for Ravenswood Pump Station. A major concern was whether the flow controllers of the Tamworth Bank and the Dandalup Bank would be able to operate together in a stable manner. The two pump banks draw water from a common trunk main without an intermediate tank and, therefore, interact hydraulically. The concern was that the flow control loops would interact in a way that would result in the banks “hunting” for their flow setpoints, without ever reaching a stable condition where both banks would be running steadily, side by side. Another concern was the ability of the control system to prevent the pressure at the suction side of the pump station from dropping too low. The pumps require a certain minimum suction pressure to operate
Figure 3. Pump bank control system model.
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Feature Article Another aspect related to pump operation that required attention was the sequences for stopping and starting of the banks. The simulations in the early design stages highlighted that each bank had its own unique problem when it came to starting the bank.
Figure 4. Control diagram â€“ pump bank control system. without cavitation issues (minimum net positive suction head or NPSH). This minimum required suction pressure also places a constraint on the transfer capacity of Ravenswood Pump Station, because the pump station draws down the suction pressure in order to increase the flow rate through the system. The ability to meet the design capacity of the pump station therefore relied on being able to draw down the suction pressure without causing problems for the pumps. The testing involved incorporating the control strategies into the WANDA model and simulating how the control system responded to a number of normal operating scenarios and failure scenarios for the future Southern System. Normal operating scenarios included the starting and stopping of either the Tamworth Bank or the Dandalup Bank and flow setpoint changes with both banks running or either bank running by itself. Simulated failure scenarios included pump trip (sudden stop) of the pumps in one bank while the other bank remains running, and the sudden closure of a source regulating valve (sudden cease of supply). The simulations made it possible to compare the performance of the different control strategies in terms of response, stability and the ability to limit the suction pressure from dropping too low. This resulted in the selection of one control strategy to develop further into the control system design for Ravenswood Pump Station. Detailed design In the detailed design stage the focus shifted to working out the details of the control system design and documenting the control logic so that it could be programmed. During this phase of the design process the WANDA model was used to simulate design options for problems that required solving. This involved developing potential solutions, incorporating these solutions in the model and running simulations to test their performance. This often involved an iterative process until the desired result was achieved. After the control logic was fully developed and documented, the model was used to determine preliminary control settings for proportional-integral controllers as a starting point for the commissioning of the control system. An aspect that required attention during the detailed design stage was the control logic for automatically starting and stopping pumps within a bank. The pumps in the Tamworth Bank and Dandalup Bank are able to operate safely between 50 per cent and 110 per cent of their best efficiency point (BEP) flow rate. Pump operation outside of this range for an extended period of time may cause damage to the pumps. In terms of energy efficiency, it is most efficient to operate the banks with the fewest number of pumps possible. The control logic for automatically starting and stopping pumps within a bank was designed to operate the bank with the fewest number of pumps possible for a given flow rate, while also protecting the pumps from operating outside of their safe operating ranges.
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The Tamworth Bank always starts with already established gravity flow in the Stirling Trunk Main. The bank therefore starts with pump flows that are often too high for the pumps to operate safely, until the pumps reach a speed where the pump flow falls below 110 per cent of best efficiency pump flow. To ensure the pumps operate within the safe operating range during start-up, the Tamworth Bank always starts with three pumps simultaneously and against a partially closed valve. The valve is slowly opened after the pumps reach a high enough speed for the pump to operate without the aid of the valve. Getting the start-up sequence right required a number of simulations with the WANDA model. The Dandalup Bank experiences problems with low pump flow during start-up of the bank. To overcome this issue, the speed of the starting pump is ramped up quickly until the first flow develops. After this point is reached, the control system is switched on and the flow controller adjusts the pump speed more gradually until the desired flow setpoint is reached. Commissioning Although the system modelling made it possible to test the detailed design of the control system for Ravenswood Pump Station before implementation, the control system still needed to be commissioned to prove that everything would work in the actual pump station. Because control system modelling is still a relatively new tool, the decision was made to validate the control system model for Ravenswood Pump Station during the commissioning stage. The validated model could then be used to simulate commissioning tests that were particularly hard to set up in the real system, saving time and effort. The hydraulic model of the Southern System was first calibrated with a steady state field test that measured pressures along the Stirling Trunk Main for a number of different flow rates. This calibrated hydraulic model was then used to replicate a number of test scenarios for Ravenswood Pump Stationâ€™s control system. The control system model was first calibrated by replicating the field data of one set of commissioning tests. This involved adjusting the control settings in the model until the simulated pump speeds, flow rates and pressures showed close agreement with the pump speeds, flow rates and pressures recorded by the SCADA system. The field data of a second series of commissioning tests was then used to validate the model by simulating the test scenarios, without further adjustment of the control settings in the model.
Results System control stability One of the results of the control system modelling in the early design stages was that the model showed that the two banks could be operated in a stable manner, with both pump banks controlled by flow control loops. The flow control loops of the two banks do interact with each other, but this interaction was not nearly as significant as was initially anticipated (GHD, 2009). As it turned out, the Tamworth System and the Dandalup System behave quite differently from a dynamic point of view. The Tamworth System, by design, has high flow rates and low static head, while the Dandalup System has relatively low flow rates and high static head.
Figure 5. Simulation results – Tamworth Bank automatic pump start. The relatively high flow rates and friction losses in the Tamworth System translate into a faster dynamic system response, i.e. due to higher friction, the flow rates in the Tamworth System settle relatively fast. The relatively low flow rates and friction losses in the Dandalup System translate to a slower, more oscillatory dynamic system response, i.e. due to low friction, pressure waves travel up and down the Dandalup System more easily before damping out. Therefore, the flow rates in the Dandalup System only settle after a relatively long time. A strong interaction between the two flow control loops would be much more likely if the Tamworth System and the Dandalup System were more similar in dynamic behaviour. Instability would also be more likely if the Dandalup flow control loop were to be tuned to respond as fast as the Tamworth flow control loop. Control system design of Ravenswood Pump Station After testing three control strategies, a control system consisting of a master flow controller and slave delivery pressure controller was selected for both the Tamworth Bank and the Dandalup Bank (Figure 4). In the selected control strategy, the flow rates of pump banks are controlled indirectly by the master flow controllers by controlling the delivery pressures of the pump banks. The flow setpoints for the Tamworth Bank and Dandalup master flow controllers are set by the remote operator, based on the target daily transfers to, respectively, the Tamworth System and the Dandalup System (GHD, 2009). The control strategy selected for the two pump banks has the benefit that the control system can cope with a loss of flow meter signal. In this situation, the control of a bank would revert to delivery pressure control only, using the last known delivery pressure setpoint. The control strategy selected was shown to perform well in controlling the flow rates of pump banks, both in simulations and at other variable speed pump stations in Perth’s Integrated Water Supply Scheme (IWSS). In addition to the flow control feedback loop, the control system also includes a suction pressure override on the Tamworth Bank that prevents the pressure on the suction side of Ravenswood Pump Station from dropping too low. Automatically starting and stopping pumps
Figure 6. Model validation – Dandalup Bank pump speed and flow rate. exceeds 110 per cent of BEP. When the flow rate drops, a pump is stopped if the average pump flow for a bank falls below 105 per cent of BEP. The last pump running in a bank is only stopped when the pump flow falls below 50 per cent of BEP. This control logic ensures the pumps operate as closely as possible to their BEP. When the control logic triggers an additional pump to start, the starting pump simply ramps up at a constant rate until it reaches the speed of the pumps already running (Figure 5). When the flow controller starts noticing the effect of the starting pump, it will automatically adjust the speed of all pumps until they are running at the same slightly reduced pump speed. Model validation The WANDA model for the control system of Ravenswood Pump Station was calibrated and validated using SCADA data recorded during commissioning tests. For the model validation, the initial conditions in the hydraulic model were set up using SCADA data and the bank start-ups were simulated using the control parameters established in the model calibration. The validation results for startup of the Dandalup Bank are presented in Figures 6, 7 and 8. The results of the WANDA model validation (Figures 6 and 7) show that the delivery and suction pressures captured by SCADA during start-up are replicated accurately by the WANDA model. The SCADA data for pump speed and flow rate are replicated accurately during the first part of the start-up. There are small discrepancies between the flow rate and pump speed captured by SCADA and the values calculated by the model for the second part of the start-up, but the overall control response is replicated well. Figure 8 shows the operating ranges for one, two and three Dandalup Bank pumps running in parallel. The limits of the operating ranges are the pump curves at maximum and minimum speed, and the curves for 50 per cent and 110 per cent of BEP pump flow. The figure also shows plots of the bank flow rate versus the pump head, referred to here as the “transient duty points”, for the SCADA data and the simulation results.
The simulations in the detailed design stage showed that the control logic for automatically starting and stopping pumps could be kept relatively simple, while still being effective in maximising the pump efficiency.
The transient duty point shows where the bank is operating in respect to the pump operating ranges. The figure shows that the transient duty point from SCADA and the transient duty point calculated with the WANDA model follow a similar path, with only some minor discrepancies.
When the flow setpoint of a bank is increased, the pump flow will increase past the best efficiency point (BEP) flow of the pumps. An additional pump is started if the average pump flow for a bank
In reviewing the SCADA data of the commissioning test, it was noted that the transient duty point travels outside of the one-pump operating range. This would normally cause the second pump to
November 2013 water
Figure 7. model validation – Dandalup bank delivery head and suction head. start. However, the automatic start of the second pump was suppressed during this initial commissioning test. modellIng suPPort durIng system commIssIonIng The Southern System is complex and can be operated in numerous configurations of sources, supply points and flow directions for the water. In order to commission the integration works for the new desalination plant within the allotted time, system configurations were divided into shortlists of Priority 1, 2 and 3 system configurations. The priority of the system configurations was based on how critical a particular configuration is to the day-to-day operation of the system. The reduced lists of system configurations still consisted of seven Priority 1 configurations, 17 Priority 2 configurations and 29 Priority 3 configurations. Although commissioning tests had to be conducted on the real system for a number of configurations, the agreement between the model results and the SCADA data was so close that a significant number of tests could be conducted with the validated model. This greatly reduced the time and effort, and hence overall cost, required to complete the system commissioning. The validated model of the Southern System and Ravenswood Pump Station’s control systems was also used to simulate commissioning tests with the model first, before undertaking the tests on the real system. This gave commissioning personnel insight into the expected performance of the system and reduced the risks of conducting the commissioning tests on a live system with customers connected.
conclusIon This article describes the benefits of the use of control system modelling as a tool in the design and commissioning of pump station control systems. In the early design stages control system modelling provides the means to explore the dynamic behaviour of a water transfer system and to compare the performance of different control strategies. During detailed design, the control logic for pump station control systems can be developed and tested in detail on the model of the water transfer system and pump station control system. This reduces the risk of delays and last minute design changes to the control logic due to unexpected issues in the commissioning stage. In the commissioning stage, a validated control system model can play a vital role by reducing both the risk and the number of commissioning tests conducted on the real system. In the case of the integration works for the Southern Seawater Desalination Plant, the control system model for Ravenswood Pump Station contributed
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Figure 8. model validation – Dandalup bank transient duty point. to getting the integration works commissioned on time and within budget. As such, the use of control system modelling can greatly reduce the time and effort, and hence overall cost, required to complete system commissioning.
AcKnowledgements The Authors wish to acknowledge the Water Corporation and GHD for their permission to publish this paper. Ravenswood Pump Station was planned by the Water Corporation, designed by GHD and commissioned by the Water Corporation with support from One Stone Consulting. The Authors also wish to acknowledge Chengchao Xu, Anthony McLaughlin, Mark Holmes, Wayne Keenan and Angelmo Shanmuganathan, and all other personnel involved in the planning, design and commissioning of the SSDP Integration Works. wJ
the Authors eelko van Der vaart (email: eelko@ onestoneconsulting.com.au) is the Director and Principal Consultant of One Stone Consulting. He is a Civil Engineer with 13 years of experience in the water industry, both in Australia and in the Netherlands. Faris Hernich (email: faris.hernich@watercorporation. com.au) is a Civil Engineer with over 24 years of experience in the water industry. He provides leadership of an infrastructure planning function and manages the Operational Modelling Group in the Water Corporation.
references Bequette B (1957): Process Control, Modelling, Design and Simulation, Prentice Hall International Series in the Physical and Chemical Engineering Sciences. Deltares (2008): Wanda 3 Help – User Manual. Deuerlein J, Simpson AR & Gross E (2008): The Never Ending Story of Modelling Control Devices in Hydraulic Systems. 10th Annual Symposium on Water Distribution Systems Analysis, American Society of Civil Engineers. GHD (2009): Southern Sources Transfer System Modelling – Control System Analysis Ravenswood Pump Station. System Modelling Report for Water Corporation. Infrastructure Planning Branch (IPB) (2009): IWSS Southern Source System – Southern Seawater Desalination Plant Stage 1 (50 GL.a) 2011. Water Corporation Planning Report. Van Der Vaart E, Holmes M, Hernich F, McLaughlin A & Xu C (2010): Dealing With The Complexities Of Integrating Perth’s Second Desalination Plant. Ozwater’10, Brisbane. Van Der Vaart E, Xu C & Hernich F (2012): Control System Modelling for a Large Scale Pumping Station. 14th Annual Symposium on Water Distribution Systems Analysis, American Society of Civil Engineers.
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This complex and challenging venture was successfully delivered on time and within budget
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DECEMBER 2013 • WATER PRICING • DEMAND MANAGEMENT • DISINFECTION • CUSTOMER SERVICE
58 Candowie Reservoir and dam structures during the 2007 drought.
• RESOURCE RECOVERY & MANAGEMENT
VARIABLE SPEED DRIVES (VSDS) AND EFFICIENCY IN THE WATER AND WASTEWATER INDUSTRY Can VSDs save energy in water and wastewater applications? L Fennell
“The VSD represents technology that boosts the performance of an electric motor and saves energy. VSDs enable more cost-effective production, reduce the greenhouse effect and play a part in meeting emissions targets. Despite this, less than 1 in 10 electric motors in the world is fitted with a VSD – financially it would be justified to install a VSD on at least 1 in 3 electric motors.” The above quote comes from the CEO of a VSD manufacturer. Much is made of the virtues of using electronic variable speed drives – sometimes referred to as Variable Voltage Variable Frequency (VVVF) drives or Adjustable Speed Drives (ASD). As energy costs continue to climb and the purchase price of VSDs continues to fall, the number of articles that urge you to install one and save a fortune appear more and more often. However, much of the data used to justify claims such as the one above are based on case studies that may not be representative of loads commonly found within water and wastewater systems. Many of the claims regarding potential savings are based on case studies that feature centrifugal pumps or fans grossly oversized and/or required to operate continuously and/or operate while throttled, but then extrapolate these figures and apply them to all motors1. These studies led to statements such as “it was found that 75% of motors were operated at below 60% load”2 – which may be true for some segments of industry but cannot be relied upon as statements that apply widely. While VSDs do not improve motor efficiency (in fact, they do the complete opposite, although not necessarily to a great degree), they may help to match pump shaft power and torque to load. By their nature case studies usually involve existing equipment and so do not allow for fundamental changes that cost far
less to implement when introduced at design stage – such as changing the size and number of motors required – which may provide a cheaper and more efficient installation. In short, if a 10% energy saving in operating a piece of equipment purely through the use of a VSD cannot be demonstrated, it will probably require more energy to operate the same piece of machinery without one. Compare the two scenarios represented in Figure 1. This is something not generally mentioned in discussions regarding VSDs and energy savings. Why does such a lot of energy need to be saved before there are any overall savings? The current drawn by a VSD is not sinusoidal as is the mains power supply. The VSD rectifies the incoming supply to DC then generally uses a process known as pulse width modulation (PWM) to replicate a sine wave (see Figure 2). The conversion of an alternating current fixed frequency supply into a VVVF supply uses energy within the VSD and causes electrical disturbances (harmonics) on both sides of the VSD, all of which in turn
cause heating. This is released to the atmosphere via cables, transformers, filters etc on the upstream side and by cables, the driven load and any other devices connected to the cable on the downstream side. All this heat can’t be just allowed to build up inside switch rooms, so it is either carried away via ventilation fans, air-conditioning or, in some cases, through cooling water pumped through the VSD itself. Needless to say, just getting rid of the heat consumes yet more energy. How hard is it to save 10% of the energy input? Sometimes it is very easy indeed – in particular, when one of the following is true: 1.
The motor is oversized for the actual shaft load;
The motor handles a load that varies considerably in terms of either speed or torque requirements;
In the case of pumps, the pump load is made up of largely friction head not static head.
Energy in = 100% 100%
Heat 10% (without VSD 8%)
Figure 1. Where does the energy go?
NOVEMBER 2013 WATER
Figure 2. Schematic representation of Pulse Width Modulation (PWM). Consider in more detail each of the above conditions, which may mean the use of a VSD is justifiable: a.
Oversized motor and/or pump. This condition exists typically where pumps have been sized for maximum expected load (i.e. future growth is expected), which almost never occurs, or the actual load was overestimated. At the extreme end, this situation may involve a pump being heavily throttled to reduce output or a motor running well below its rated output and, therefore, well below its maximum efficiency. In each case a VSD will assist in saving energy on an existing facility. It should be noted, however, that this is a case of treating the symptom and not the cause – a pump chosen carefully to match load and output will be more efficient than using a poorly matched motor and pump with a VSD. At the more minor end of the scale the pump and/or motor may be operating intermittently using a lot of power when operating, as opposed to operating for longer at much lower power when a saving in energy may result.
The motor handles a load that varies. An example of this situation would be a cooling water pump. The pump is required to operate to move cooling water, but the actual amount of water required to be moved varies depending on the cooling requirement. A VSD enables the pump to slow to match the load.
The pump load is largely made up of friction head. This is the most relevant example to the water and wastewater industry. In the case of pumps moving fluid from one location to another – either within a treatment facility or as part of a collection or distribution system, the balance must be struck between saving energy in friction (which is controllable via pumping rate), and the potential negative
WATER NOVEMBER 2013
effects of changing the shaft speed of a pump, in terms of efficiency. Clearly, when the total head is dominated by static head there is no saving by pumping at a lower rate – in fact, almost always the opposite is true and a VSD will simply result in more energy being used.
If none of the three criteria above is true then, in general, using a VSD will require more energy to achieve the same amount of work than not using one. That is not to say that there are not many other reasons why a VSD might be a good idea – but claiming that there are energy savings is not one of them.
It is widely known that, theoretically, a centrifugal pump will deliver 80% of its maximum flow with just one half of the power required to obtain 100% flow, by virtue of the fact that shaft power is roughly proportional to the cube of shaft speed for centrifugal pumps. But using this fact to decide on operating philosophies when pumping between storage tanks depends on one important point – the overall energy input per unit of volume pumped.
There are two further areas where VSDs will introduce additional costs, whether or not their use results in any form of energy saving. First, the additional requirements for screened cables and filters to avoid interference to nearby equipment from transmission of electrical noise, as well as higher temperatures expected within the windings of motors, thanks to harmonics. Second, the additional costs of a more complex design in terms of procurement of equipment and software, and due to the additional complexity involved in commissioning such a system.
Consider a pump that has been slowed so it is now incapable of overcoming the static head it faces. As can be imagined, as pumps reach this operating point their efficiency approaches zero. All energy applied is wasted as no useful work is carried out. At the other end of the scale, every pump has, for any given speed, a ‘best efficiency point’ (BEP). This is ideally where the pump will operate for maximum efficiency. Not surprisingly, the BEP is often where a fixed speed pump operates at the specified duty – this is because the pump supplier will try and match the pump duty with a pump running as close as possible to BEP. As soon as the speed of the pump is varied, great care must be taken to ensure that energy is not being wasted simply because the pump is no longer operating as efficiently as possible. It might seem a great saving that the pump uses just one half of the power by dropping the shaft speed – but that saving is actually an expense if, in fact, it then takes more than twice as long to move the same volume of liquid when there is no other reason to pump slowly.
This second cost is essentially related to how it will work. It is much more complicated to write software or design control systems to operate machines with varying speed – particularly when the feedback loop is analogue in nature. Where the idea is to vary the speed in response to some control loop, this relationship needs to be explained fully and then turned into code. This then needs to be implemented by programming the VSD in harmony with the rest of the control system and then typically factory-tested with simulation before arriving at site. A full test then needs to be carried out on-site as part of commissioning. All this testing takes time both in preparation and in carrying out tests. While such a system is perhaps more flexible in terms of being able to meet future requirements, testing, commissioning and maintaining such a system will inevitably cost more and may present higher risks associated with the
use of complex, bespoke software as opposed to much simpler on/off control. The perception that the use of a VSD will reduce risk during the design phase should be viewed with suspicion as a well designed, fixed speed system will always be cheaper and faster to design, procure and test, and ultimately cheaper to maintain. In summary, VSDs can and will continue to make a tremendous contribution to increases in efficiency and reduction in power used in some applications. Their use in order to save energy is best applied when: 1.
Varying and inefficient means of control are currently being utilised (i.e. throttling of valves);
In the case of pumps, the friction head is high and the static head is low;
The driven equipment is oversized for the average load. Much of the information and examples
used are not relevant to the water and wastewater industry and come largely from the building services industry, which regularly features motors operating for long periods of time, partly loaded or controlled in horribly inefficient ways such as bypassing or using crude means of throttling. Take any claims regarding vast energy savings via the use of a VSD with a big pinch of salt, and if there is some doubt regarding how energy savings are calculated try comparing the situation where the VSD simply operates the motor at its normal fixed speed. If the calculation or worksheet still shows energy savings, you know something is not right. While it appears certain that energy costs will continue to rise, the decision to use a VSD should be considered by taking all the costs of making such a decision into account. The client may temporarily be impressed that the VSD
does, in fact, save some energy – but the fact that they may also have overheating switchrooms, power quality issues, difficult-to-maintain software, higher maintenance costs of the VSD itself, and complex operating procedures as a result will not be forgotten in the longer term.
Finally, as someone recently pointed out, if VSDs are so good at saving power in so many applications – how come cooling fans on large VSDs aren’t fitted with them? An interesting question indeed.
THE AUTHOR Luke Fennell (email: Luke. Fennell@edtc.com.au) is a Sydney-based electrical engineer with 20 years of experience. He currently part-owns and operates a business that specialises in the design and commissioning of water and sewage pumping stations and treatment plants.
VSDs for Electric Motor Systems – published by the European Commission, Directorate-General for Transport and Energy, SAVE II Programme, 2000, page 48, Table 3.3.
A review on electrical motors energy use and energy savings. Renewable and Sustainable Energy Reviews, Issue 14; 2010, page 896.
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WESTERNPORT WATER’S CANDOWIE RESERVOIR UPGRADE AND WATER SUPPLY SECURITY PROJECT This complex and challenging venture was successfully delivered on time and within budget C Jayasena
Located within the Bass Coast Shire 100km south-east of Melbourne, Westernport Water is one of 19 Victorian water corporations providing water and wastewater services. Servicing an area of 300 square km and 17,300 customers (Figure 1), Westernport Water is challenged with providing services to over 100,000 people during major events and peak holiday periods.
A comprehensive business case was undertaken to assess and identify that an upgrade to Candowie Reservoir was the best way to ensure the most economical water would be available for future demand.
Candowie Reservoir is the sole water storage for the region serviced by Westernport Water. Built in 1963 and raised to a capacity of 2,263ML, the supply vulnerability of the annual fill and empty cycle of Candowie was exposed in the 2006–2007 drought period when the reservoir capacity fell to just seven per cent and Stage 4 water restrictions were imposed (Figure 2).
The business case was independently assessed via the Department of Treasury and Finance (DTF) Investment Gateway Review Program and was submitted to the Department of Sustainability and Environment (DSE) for further review. The program included the following: I.
Development of Water Supply Demand Strategy
The Candowie Upgrade Project (CUP) was a key component in Westernport Water’s Water Supply Demand Strategy (WSDS), providing the planning framework for the reliable supply of water through to 2055. The CUP involved embankment crest wall upgrade and other associated infrastructure works, raising the full supply level of the reservoir by three metres, effectively doubling its storage capacity to 4,463ML. The preference to upgrade the existing reservoir maximised the opportunity for Westernport Water to collect, store and treat the most economical water available. After a rigorous multi-year review process, the business case for the CUP was approved in March 2012. The construction phase of the project commenced in September 2012 and less than a year later was completed in August 2013, while water storage and treatment operations continued.
WATER NOVEMBER 2013
Figure 1. The Westernport Water region.
Identification and analysis of options scope, designs and costing
Recommendation and implementation of the preferred solution. The project design phase commenced
in 2010 and included a functional design covering the hydrological survey, upgrade options for key structural elements and an impact assessment for surrounding properties. The detailed design was completed in 2011 to cover the detailed geological investigations for embankment and spillway works, detailed structural design drawings, specifications for works packages and engineering estimates.
Pre-cast panels were lined against the existing crest wall (Figure 4). The in situ base concrete was poured on top of the horizontal sand filter to support the pre-cast wall panels. The 2B and 3A rock filters were placed on top of the base slab and these filters were installed to capture any leakages in the new crest wall joints. RESERVOIR SPILLWAY UPGRADE
The spillway was upgraded for 1:100,000 AEP (Annual Exceedance Probability) flood event and the upgrade works involved upgrading the spillway return walls to the new crest height, extending the chute walls and slab, strengthening the chute slab, and a new ogee for the design flood flow of 120m3/s. Figure 2. Candowie Reservoir and dam structures during the 2007 drought.
PROJECT COMPONENTS EMBANKMENT AND CREST WALL UPGRADE
The embankment was upgraded with a downstream clay fill placed over the existing embankment to support the additional load due to the increased capacity (Figure 3). The fill material for the new downstream embankment was sourced from local quarries. The embankment fill was continued up to
the base slab of the crest wall and the existing chimney sand filter was extended and connected to the horizontal 2A sand filter under the concrete base slab. The sand filters were designed to catch any water seepage through the embankment cut-off wall. CREST WALL
A new crest wall was constructed using pre-cast concrete panels. The panels were 2.0 to 2.4m wide and 5m high.
OUTLET STRUCTURE UPGRADE
The outlet structure was raised and upgraded for floatation and dynamic loads. Four permanent post-tensioning anchors installed outside the tower were drilled 16m into the rock under the tower foundation. The offtake pipe and valves were replaced and a new 450mm offtake was installed at a level 3m higher. Three offtakes will provide the option of drawing water at different levels, depending on the raw water quality parameters.
Figure 3. Sectional drawing of the embankment upgrade.
NOVEMBER 2013 WATER
Figure 4. The new pre-cast crest wall. A new walkway bridge was installed (Figure 5) to provide access to the outlet structure. The outlet structure was completed with a new lighting and ventilation system.
PROJECT CHALLENGES A number of significant challenges and demands was successfully managed during the execution of the project, including: I.
Continuity of water supply during outlet tower upgrade
While the main outlet tower was isolated from the system for its upgrade works, a temporary water supply system was constructed to provide raw water to the treatment plant. The temporary raw water system consisted of a floating pump, 350mm diameter HDPE pipeline, a flow meter, non-return valve and chemical injection system. The temporary pump had the capacity to cater for the average system demand of 110L/s and provided the raw water to
Figure 5. Outlet tower and walkway upgrade. Outlet tower post tensioning ground anchors and geological exploration
the treatment plant operation during the construction works.
Upgrade works of the tower pipe system were scheduled in the early stages of the project, aiming to commission the new pipeworks before the Christmas peak demand period. The complete offtake pipe upgrade was a construction challenge. The new riser pipe was fabricated and galvanised off-site and needed to be precisely matched with the old pipe configuration in order to fit the new pipe flanges, which were embedded in the outlet structure concrete. The old riser pipe was dismantled, transported to the factory and reassembled with the complete riser pipe to produce the shop drawings for the new riser pipe. The new riser pipe was fabricated and pressuretested at the factory, before being transported to the site.
The outlet tower was upgraded to new earthquake design standards. The detailed design was to install four ground anchors with 19 strands. Geological investigation under the tower base was not carried out during the detailed design, due to the high mobilisation cost of the drill rig and barges. As a result, the geological investigation was included in the contractorâ€™s scope of works and the detailed core drilling was completed before the permanent anchor drilling.
New flexible couplings were introduced between the riser pipe and the new valve with the intention of providing tolerance for any minor fabricating misalignments.
Overview of physical characteristics of the upgraded Candowie dam
The rock-bearing strength of the core samples was very low compared to the initial design assumption. The detailed design was reviewed and anchor lockup loads were reduced accordingly. The rock strength immediately under the tower base was assessed as 400kpa compared to 1000kpa in the design; so the number of strands was reduced to seven and the lockup loads of the anchors reduced accordingly.
Height of the dam (base to crest)
Earth and rock-fill with concrete parapet wall
Length of wall
Date of construction
1962 raised in 1978, 1982 and 2013
Dam hazard category
Size category (ANCOLD)
Capacity at FSL
21m-wide concrete ogee crest
The water test was carried out to assure the drill hole water tightness, and due to the fractured nature of the rock the water test failed several times. The anchor holes were conditioned using cement grout mix to improve the impermeability of the anchor holes. The contract allowed for one round of conditioning and any extra conditioning and redrilling was treated as a variation.
Design flow of spillway
120m3/s at 1:100.000AEP
Dry concrete tower â€“ 17m deep
600mm diameter riser pipe with 2x300mm and 1x450mm supply offtakes
WATER NOVEMBER 2013
in the live reservoir and contract interfaces
The construction site was adjacent to the water treatment plant and pump stations.
Figure 6. Leakage under old crest wall base slab. As such, all work practices and methodologies had to be extensively planned and coordinated to ensure disruption to the reservoir or water treatment plant operation was minimised. The spillway upgrade was a challenge in the live reservoir. A temporary cofferdam was constructed before the start of spillway works, and the reservoir water level was lowered to a pre-agreed level by operating newly installed outlet tower pipe works and the scour valve system. Westernport Water agreed to maintain the water level below the cofferdam level in normal operating conditions. However, there was potential exposure to flood damage to the works during uncontrolled inflows into the reservoir. A detailed flood study was carried out to determine the inflows and discharge capacities. The upstream works were scheduled between February and May, immediately after the peak water demand period, while the reservoir level was at its annual lower water levels. The cofferdam was removed immediately after the completion of the final ogee concrete pour. Maintaining reservoir water levels was well managed by Westernport Water without inconveniencing customers with shortterm water restrictions. The reservoir refilling cycle began in June 2013, using Westernport Waterâ€™s bulk entitlement licence to pump water from the Bass River, inflows from Tennent Creek and run-off from the catchment.
Water quality constraints
Upstream construction works were carried out within the reservoir, which required extremely high levels of environmental and water quality control. This was addressed from day one by monitoring the water quality of the reservoir combined with toolbox meetings with the contractor. One of the challenges was how to accurately transfer this high-level control information to the workforce. While the outlet structure anchor drilling was in progress, there was a risk of increasing raw water turbidity due to the disturbance around the outlet tower base. Operation of the treatment plant was limited to night operation during the anchor drilling and Westernport Water consistently maintained the treated water storage above the normal operating level to avoid water restrictions caused by any system failures during the outlet structure construction works. V.
Water tightness of the pre-cast crest wall
The new 166m long crest wall was a combination of pre-cast parapet wall panels and in situ concrete on the right and left abutment walls. The pre-cast concrete technology was applied to reduce the construction time and to ensure a high quality product through factory-based manufacturing.
The crest wall panels were sized between 2.0mâ€“2.4m considering the lifting capacity and erecting facilities. Integration of the new crest panels with the existing concrete wall and water tightness of the construction joints constituted a significant construction task. This was achieved by introducing multiple water-proofing barriers and water membranes. The upstream side of the wall was sealed with vertical and horizontal water-proofing membranes. In between the pre-cast panels, additional expandable waterproof materials were placed. Figure 4 shows the pre-cast wall joints and two horizontal water seal joints in the previously upgraded walls. VI. Incomplete
information and geological investigation
Difficulties were encountered during the detailed design and construction phase due to incomplete records on existing structures, as well as old and incomplete original plans. The parapet wall on the right-hand side of the spillway return wall was excavated to investigate what was originally built in this location. This was required due to a persistent leak in this area through the spillway wall joint. The concrete block supporting the slab panel was not shown on the original plan and did not extend to the original parapet wall upstream of this position. The joints were resealed and the hole filled with concrete (Figure 6). Extensive geotechnical investigations were required during the design phase to support design assumptions and confirm details not recorded on existing plans. vii. Commissioning challenges The environmental investigation suggested that the first dam filling would be required to be carried out over a two-year period to mitigate the impact of works on wildlife, including the endangered giant Gippsland earthworm. With an uncontrollable catchment flow and limited discharge capacity, controlling the recharge of the reservoir was an operational challenge.
NOVEMBER 2013 WATER
Technical Papers A commissioning plan was prepared and improved surveillance and monitoring was also employed to ensure the dam integrity during the first filling cycle. Main construction works were sc heduled to be completed by June 2013 to allow for the refilling of the reservoir during the regular winter rains. This was considered high priority as the new works needed to be tested and commissioned before the end of the 12-month defect liability period. Westernport Water commissioned the Bass River pumps to accelerate the filling rate in addition to the natural catchment flow. The maximum desirable filling rate for the new works was estimated to be 150mm/d and the continuous monitoring of the reservoir water levels was required during the first filling cycle to maintain the rate of fill below the preferred level. A follow-up environmental investigation provided reassurance that the giant Gippsland earthworms were probably not present, and so this issue imposed no requirement on the refilling process.
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CONCLUSION The Candowie Reservoir Upgrade Project was a complex and challenging venture successfully delivered on time, within budget, and with no significant events or incidents causing lost time injuries. This was achieved through strong project management, clear leadership, intensive planning and coordination, and through a true collaborative relationship between contractors, designers and Westernport Water employees, which enabled all parties to perform at an exceptional level. The extensive project challenges demanded a high level of ingenuity, with a focus on safe design and work methods, to ensure that all the project goals were achieved. The completion of the infrastructure has provided major benefits and value for money to Westernport Waterâ€™s customers, through the increased capacity of an additional 2,200ML of sustainable economic water supply. A larger water storage will provide water supply security, greater opportunities for water management, optimise the use of
all available local water sources and deliver a safe, affordable water supply to the communities serviced by Westernport Water. This project clearly demonstrates that renewing and upgrading existing infrastructure can be a viable alternative to new projects.
ACKNOWLEDGEMENTS The Author wishes to thank Contract Superintendent Steven Porter; Project Director Stephen Cannon; Candowie Dam Wall and Spillway Upgrade Contractor GeoTech P/L; Roadworks and Earthworks Contractor Goldsmith Environmental; Detailed Design Engineers Entura Consulting; Functional Design Engineers SKM; and Water Supply Modelling Engineers GHD.
THE AUTHOR Chaminda Jayasena (email: cjayasena@ westernportwater.com.au) is the Senior Project Manager at Westernport Water, Victoria. He managed the tender and construction phase of the Candowie Upgrade Project.
USING A REAL OPTIONS APPROACH TO VALUE THE BENEFITS OF CONDITION ASSESSMENTS WITHIN A RISK-BASED ASSET MANAGEMENT FRAMEWORK An approach to measure and monetise the value of acquiring increased certainty on potential investments in assets M Bendeli, A Hersh
ABSTRACT Condition assessments are an important asset management activity for infrastructure organisations such as water utilities, providing them with a better understanding of an asset’s likelihood of failure than may be determined from a desktop assessment using cohort service life estimates. Verifying the condition of assets helps utilities to optimise the financial efficiency of their maintenance and renewals works programs, by deferring investment on those assets that are found to be in a better condition than expected (from desktop assessment) and by realising a greater reduction in risk by renewing/rehabilitating assets that are found to be in a worse condition than expected. As budget and resource constraints prohibit water utilities from performing a condition assessment on every asset in their portfolio, water utilities should also understand the cost benefit of performing condition assessments themselves so that their total works programs can be justified on a financial basis. Risk-based economic models are used by many utilities to support their asset management investment decision making, but while the benefit of maintenance and renewals activities are relatively easy to calculate (equating to the reduction in risk cost of the asset), the benefits of condition assessments are harder to quantify. This paper outlines a statistical approach, drawn from a Real Option Valuation framework, to measure and monetise the value to the
asset’s owner of acquiring increased certainty on potential investments in their assets. Incorporating this approach into a water utility’s economic model allows it to compare the benefits and costs of condition assessments to test the scale of condition assessment programs that would be worthwhile. While the paper uses buried pipeline assets as a case study, the proposed approach is equally applicable to other asset classes.
Many infrastructure organisations around the world, including Australian water utilities, approach asset management using a riskbased framework. The likelihood and consequence of asset failures and their impact on the service performance objectives of the organisation are taken into account when organisations develop and justify asset management expenditure programs to boards and economic regulators (Bendeli, 2012). The impending ISO 55000 Standard similarly recognises that asset management involves the balance of risk, cost and benefits in the realisation of an organisation’s objectives. Good asset management encourages the use of empirical data over subjective assessments, wherever practicable, to inform decision making. In this context, condition assessments are an important activity for infrastructure organisations – especially water utilities, which have a large percentage of their asset base consisting of buried pipelines (water mains and sewers) and associated
appurtenances. The structural and service condition of buried assets can have a high degree of uncertainty, being influenced by a range of asset design attributes, service/operating conditions, external environment characteristics (e.g. the presence of acid sulphate soils) and construction quality issues (Roche et al., 2013). Australian urban water utilities commonly agree that condition assessments are valuable and should be incorporated in the risk-based management of buried assets (Marlow et al., 2009). However, as budget and resource constraints prohibit water utilities from performing a condition assessment on every asset in their portfolio, economic models are used by many utilities to support their asset management investment decision making – using cohort-level service life assessment (e.g. Weibull survival curves), possibly coupled with assetspecific factors (Kane et al., 2013), to arrive at a desktop estimate of asset service life/likelihood of failure from which asset management expenditure programs are developed. Undertaking condition assessments allow a water utility to ‘verify’ the condition of its assets (against the desktop estimate), thereby helping its maintenance, rehabilitation and renewals programs to be better targeted to problematic assets/cohorts. Condition assessments also allow other opportunistic site and service data to be collected, and condition assessment data can be used to calibrate the economic models.
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Technical Papers A condition assessment may not be an economically justifiable decision on all assets, however. Some assets may be young enough that deferral of this expenditure is prudent, and some assets may present sufficiently low risk to a utility such that it is economically efficient to manage them in a reactive (run to fail) manner. Asset managers should ensure that their programs of work – including condition assessment programs – are managed in a cost-effective manner, at a level of service that is broadly affordable to the community. Water utilities should also understand the cost benefit of performing condition assessments themselves, and incorporate these into economic models so that the total asset management works programs (not just maintenance and renewals programs) can be justified on a financial basis. THE DIFFICULTY OF VALUING THE BENEFIT OF CONDITION ASSESSMENTS
While the benefits of maintenance and renewals activities are relatively easy to calculate (equating to the reduction in risk cost of the asset), the benefits of condition assessments are harder to quantify. The benefit from a condition assessment cannot be derived from a reduction in risk cost, as condition assessments serve to collect information and verify condition rather than treat any components of risk. Rather, the benefit of a condition assessment is realised in the increased accuracy provided to the utility about the likelihood of failure of its assets, enhancing the capability of the asset owner in making investment choices. Verifying the condition of assets helps utilities to optimise the financial efficiency of their maintenance and renewals works programs by deferring investment on those assets that are found to be in a better condition than expected (from desktop assessment), and by realising a greater reduction in risk by renewing/rehabilitating assets that are found to be in a worse condition than expected. This value of the enhanced decisionmaking ability of the owner of the asset, resulting from the condition assessment, is calculated using a real options analysis (ROA) based approach, which is used regularly in the analysis of infrastructure project financing. An ROA-based approach, unlike a traditional net present value (NPV) approach, is able to recognise and value the managerial discretion of the owner1.
METHODOLOGY This section describes the ROA-based approach in a statistical manner (showing the way in which real options analysis captures the benefit of condition assessments); and then presents an illustrative numerical example based on realistic industry figures to illustrate the robustness and transparency of the proposed approach.
The feasibility of this investment by the owner is described by the following NPV equation:
The consequence of failure, C(f), measured in dollars, is cost incurred in the event of failure. The likelihood of failure, L(f), measured as a percentage, is estimated based on the age of the asset, typically with a Weibull curve as illustrated in Figure 1 (Weibull being a commonly used service life curve for buried pipeline assets; Gata et al., 2011). In Figure 1, the estimated Weibull curve is presented as the middle purple line; however, as the Weibull curve provides only an approximation of the likelihood of failure based on an assets age class, the likelihood of failure for a given age is uncertain and lies between an upper and lower bound. As illustrated, the cross section of each asset age class can be described by a distribution, with a mean and standard deviation. That is, the Weibull curve is, in effect, the ‘mean curve’ for the range of likelihood of failure at any given age. The risk cost of the asset can also be described by a distribution of possible risk costs2. For mathematical simplicity, this paper will assume the distribution can be described by a normal distribution3 with a mean of μ and a standard deviation of σ.
Figure 1. Likelihood of failure. The NPV of an ‘asset replacement investment’ contains some uncertainty due to the uncertainty of the risk cost of the asset. This asset replacement NPV uncertainty can also be described by a normal distribution, such that: - If the NPVmean of the investment is positive, the asset owner should replace the asset - If the NPVmean is negative the asset owner should not replace the asset.
An example of a possible distribution of the NPV of an asset replacement investment is illustrated in Figure 2, where the NPVmean is highlighted with a thick black line.
The benefit of a condition assessment is determined as the increase in the economic value of the potential investment in a specific asset. Investment in an asset would be in the form of a treatment to reduce the risk cost of an asset. One option to reduce risk is to replace the asset.
In the absence of a condition assessment, this NPV feasibility approach will provide the owner of a number of assets with a statistically sensible approach. The owner will, on average, replace those assets that have a reduction in risk higher than
WITHOUT A CONDITION ASSESSMENT
Dixit and Pindyk (1994) note that the NPV decision rule implicitly assumes that either the investment decision is costlessly reversible, or that if it is irreversible it is a now or never decision. By recognising contingent futures and waiting for some uncertainties to resolve with time, the real options approach can value managerial flexibility, such as the option to alter its course, to expand, delay, contract or abandon (Brealey et al., 2006).
Assuming that the standard deviation of the consequence cost is equal to zero, the standard deviation of the risk cost will be equal to the standard deviation of the likelihood of failure.
A normal distribution is a reasonable distribution to describe the uncertainty of an asset classes risk cost, according to the Central Limit Theorem, due to the large number of assets making up the asset class. The assumption of a normal distribution simplifies the formula required for calculating the value of a condition assessment; however, the approach outlined in this paper can be applied to asset classes with different distributions, in which case a Monte Carlo approach would be recommended.
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replacement cost (i.e. a positive NPVmean) and not replace those assets that have a higher replacement cost than reduction in risk (i.e. a negative NPVmean). The owner should recognise, however, that there will be cases where the actual NPV of replacing an asset4 is found, after the replacement has occurred, to be higher or lower than determined by a desktop study â€“ as the replaced asset, once exhumed, is found to be in a better or worse condition than assumed. Therefore all points below the normal distribution line, as illustrated by the thin black lines in Figure 2, represent possible NPVactual outcomes. Each, of course, contributes towards the NPVmean.
Figure 2. NPV distribution of an asset replacement investment. For the occurrences where the asset replacement NPVactual is negative (i.e. in a better condition than assumed by desktop analysis), the investment in replacing the asset represents an economic loss even though the NPVmean is positive. Yet, in the absence of a condition assessment this investment still presents the best statistical choice and so the asset owner would choose to replace the asset, thus suffering an economic loss. The economic loss is equal to the cost of the replacement minus the potential reduction in risk cost. The area highlighted in red in Figure 3 represents all of the possible NPVactual outcomes that would result in economic losses.
Figure 3. Negative NPVactual outcomes. In the inverse case of a negative NPVmean the owner should statistically not invest in a replacement even though there could be specific cases where an economic positive NPVactual occurred. That is, some assets that were assumed to be in a good condition were found to be in poor condition (such as pipes unexpectedly impacted by stray currents and acid sulphate soils).
failure will not be known with complete certainty, it is assumed that the increase in certainty will be sufficient to identify which assets should and should not be replaced. The risk cost and, subsequently, the reduction in risk cost and investment NPV are, therefore, determined and no longer considered uncertain5. That is, the asset owner is able to better understand the NPVactual prior to asset replacement. While the uncertainty of the NPVmean for an asset cohort will not change as a result of a single condition assessment (although it can be improved over time through a systematic condition assessment and data analysis program), the manager of the asset will have enhanced flexibility in the decision-making process by becoming aware of the investment NPVactual for each specific asset it inspects. When a condition assessment determines that a specific asset replacement NPVactual is positive, investment will occur and, inversely, when the NPVactual is negative investment will not occur. The condition assessment will result in all possible negative NPVactual outcomes of a general assetâ€™s NPV distribution not occurring, as illustrated in Figure 4. The resulting outcomes are the representative of the upside value of the NPV distribution.
Figure 4. Upside value (where asset replacements with a negative NPVactual are not performed). Based on the above logic, the value (benefit) of performing condition assessments can thus be calculated using a Real Options Analysis (ROA) approach. Unlike a standard NPV approach, ROA recognises and values (monetised) the managerial discretion of the asset owner to make an investment decision based on the knowledge realised through a condition assessment â€“ where the asset owner has effectively purchased a real option for the flexibility to decide on investments once the specific NPVactual of each asset replacement is determined. This approach values the investment as the upside value of the NPV (the shaded area in Figure 4). The upside value of the NPV is equal to the upside potential of the investment and can be calculated as follows6 (Carmichael et al., 2011):
WITH A CONDITION ASSESSMENT
When a condition assessment on an asset is carried out, the likelihood of failure of the asset is determined and can be considered significantly more certain. While the likelihood of
While the investment decision for a single asset can only have one NPV, the distribution should be considered as representative of a large number of possible assets which comprises individual assets that have different NPVs, as described by the NPV distribution. Put another way, the investment decision for a general asset with certain characteristics will have a distribution of NPVs, however the investment decision for a specific asset will have a single NPV that is within the distribution defined by the general asset.
While the consequence of risk and investment cost, both components of the investment NPV, will contain a level of uncertainty, this analysis focuses on the reduction of uncertainty in the likelihood of risk. The uncertainty applied in the distribution, in the form of the standard deviation, will contain only the risk associated with the likelihood of failure.
This equation is for a normal distribution. The outlined approach can be used for alternative distributions, however a different calculation method (e.g. Monte Carlo) will be required.
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Technical Papers The ‘Upside Value NPVmean‘ is understandably higher than the original NPVmean as the owner of the asset now has the flexibility to exclude all specific cases where the NPVactual of asset replacement is below zero. THE VALUE OF A CONDITION ASSESSMENT
The economic value in the condition assessment is equal to the change in the NPVmean resulting from the exclusion of all possible negative NPVactual outcomes. That is to say, the condition assessment would result in the owner identifying all specific assets that were expected to have a positive investment NPVactual but do not. In the inverse case, the condition assessment would also identify all assets that were expected to have a negative NPVactual but did not. In both of these cases the truncated (upside value) NPVmean is higher than the original NPVmean and the economic value of the condition assessment is equal to this increase in NPV, as illustrated in Figure 5.
Figure 5. Increase in NPV realised through condition assessments. ILLUSTRATIVE CASE STUDY: RESULTS
In order to test the validity of the approach when industrybased figures are used, the results from a spreadsheet-based assessment process are analysed. The value of a condition assessment, as per the approach outlined above, was calculated for five representative assets classes, which are at different stages of their life. The spreadsheet module produces key economic indicators, such as NPV, for each asset.
It would be expected that condition assessments would be of most value to asset classes that are towards the end of their service life. When an asset class is far younger than its service life there is little benefit in carrying out condition assessments as, at this point, investment in the asset is unlikely to be economic. When an asset is older than its service life there is little benefit in carrying out condition assessments as, at this point, investment in the asset would likely be of economic value. The spreadsheet model is used to determine at which point the condition assessment is of most value based on the proposed approach to test whether it is consistent with the expected outcome. The length of life of the five asset classes7 is constant for each of the five assets assessed, as this allows a comparison of the value of the condition assessment for asset classes at different stages of their life. The characteristics of the asset classes chosen are provided in Table 1. Utilities that have information on the age and life of their assets and have developed an appropriate failure curve would be able to produce the data needed to conduct the outlined approach. A service life of 100 years and a length of 10m have been used for the case study. The NPV of each asset is calculated for the case with and without the condition assessment. The NPV without the condition assessment is labelled as ‘NPV’ in Table 2 and the NPV with condition assessment is labelled as ‘Post CA NPV’. For the cases where the NPV without condition assessment was positive, the value of the condition assessment is equal to the increase in the NPV post-condition assessment. For the cases where the NPV without condition assessment is negative, the owner of the asset class would not have invested in any of the assets, so the value of the condition assessment eventuates from investing in those individual assets where it was worthwhile. Therefore, for these cases the value of the condition assessment is equal to the post-condition assessment NPV minus zero. The results for the five asset classes assessed are provided in Table 3. The value of the condition assessment for different
Table 1. Asset Descriptions. Life (Years)
Likelihood of Failure
Likelihood of Failure After Replacement
SD of Likelihood
Cost of Replacement
Cost of Condition Assessment
Table 2. NPV Calculations. Asset Class
Risk Cost Before Investment
Risk Cost After Investment
Probability of Negative NPV
Post CA NPV
Value of CA
Asset classes, not individual assets, are used in the case study as practically utilities would carry out this analysis on classes of assets for program delivery, as opposed to carrying out the analysis on individual assets.
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Table 3. NPV Outputs. Asset Class
Cost of Condition Assessment
Value of CA
NPV of CA
asset classes is broken down further in Figure 6 into 10-year increments. This analysis shows that the ROA-based approach produces results consistent with those expected – where condition assessments are not economically effective for very young or very old assets; and are most economic for assets in the final third of their service life.
Figure 6. Value of condition assessments. The net benefit of carrying out the condition assessment is, therefore, determined as the value of the condition assessment minus the cost of the condition assessment. A condition assessment is considered economic if the net benefit (NPV) of the condition assessment is positive. Without budget constraints, utilities would be advised to carry out condition assessments on all asset classes for which it would be NPV-positive. In reality, utilities would need to determine the optimal balance between spending on NPV-positive condition assessments and budget available. The approach outlined provides a useful, desktop-based screening tool that provides the information necessary for identifying the optimal balance.
DISCUSSION Significant investment aimed at improving our understanding of the condition, performance and prediction of failure of critical water mains is currently being made by the water industry through the Advanced Condition Assessment and Pipe Failure Prediction Project (see www.criticalpipes.com). As we become more sophisticated in our condition assessment and failure prediction modelling techniques, so should we seek to improve the maturity of our economic justification of condition assessment programs. This paper aims to introduce the real options analysis approach to the reader and to promote discussion on the use of desktop cost-benefit valuation when developing condition assessment programs. Ongoing testing and validation of the proposed approach requires further investigation with larger data sets, in particular relating to building our understanding of: - The expected standard deviations of asset service life curves (Weibull or other) for different asset cohorts
- The level of confidence in L(f) achieved through different condition assessment techniques – including existing direct and indirect techniques (e.g. mote field eddy current and linear polarisation resistance methods), as well as emerging technologies.
CONCLUSION A real options analysis-based approach can be incorporated into the economic models of infrastructure organisations to do a desktop test of the scale of a condition assessment program that would be worthwhile, on a risk-management basis, for the organisation. Cost benefit consideration of condition assessment programs supports the economic justification of asset management activities beyond traditional maintenance and renewals programs of work.
THE AUTHORS Michael Bendeli (email: MBendeli@globalskm. com) is an Associate of Sinclair Knight Merz’s (SKM) Water Infrastructure Asset Management practice area and co-convenor of AWA’s Asset Management Specialist Network. Michael is a Chartered Professional Engineer with a Mechanical Engineering Degree from Sydney University and a Masters Degree in Water Services Management from UNESCO-IHE, Delft, The Netherlands. Ariel Hersh (email: AHersh@globalskm.com) is an economist with a background in engineering. Ariel received a high distinction for his research honours thesis on real options analysis. His research was founded on the challenge of carrying out a feasibility study on infrastructure investments that involve high levels of uncertainty and offer opportunities for flexibility. Ariel works at SKM, where he undertakes financial and economic modelling, evaluation and analysis.
REFERENCES Bendeli M (2012): Collaboration Trends for Asset Management in the Australian Urban Water Sector, Master’s Thesis, UNESCO-IHE, The Netherlands. Brealey R, Stewart A, Myers C & Allen F (2006): Principles of Corporate Finance (8th Edition), Irwin/McGraw-Hill. Carmichael DG, Hersh AM & Parasu P (2011): Real Options Estimate Using Probabilistic Present Worth Analysis, The Engineering Economist, 56, 4, pp 295–320. Dixit AK & Pindyck RS (1994): Investment Under Uncertainty, Princeton University Press. Gata Y, Kroppb I & Poultonc M (2011): Is The Service Life of Water Distribution Pipelines Linked to Their Failure Rate? International Water Association Leading Edge Strategic Asset Management (LESAM) Conference, Mulheim, Germany. Co-written: REBX, BAUR+KROPP, WTSim. Kane G, Zhang D, Lynch D & Bendeli M (2013): Sydney Water’s Critical Water Main Strategy and Implementation – A Quantitative, TripleBottom Line Approach to Risk-Based Asset Management, International Water Association Leading Edge Strategic Asset Management (LESAM) Conference, Sydney, Australia. Co-written: Sydney Water Corporation, SKM. Marlow D, De Silva D, Beale D & Cook S (2009): Blockage Management Report II: Results of the WSAA Blockage Survey, Water Services Association of Australia. Roche D, Hick J, Lynch D, Bendeli M, Marlow D & Beale D (2013): Collaboratively Building Best Practice Management of Sewer Blockages, International Water Association Leading Edge Strategic Asset Management (LESAM) Conference, Sydney, Australia. Co-written: SKM, Water Services Association of Australia (WSAA), Commonwealth Scientific and Industrial Research Organisation (CSIRO).
NOVEMBER 2013 WATER
HEAT ENERGY RECOVERY POTENTIAL FROM SEWERS IN MELBOURNE PIPES & PIPELINES
A study to determine whether heat extraction from sewers is technically and financially viable F Pamminger, D Scott, L Aye, R Jelbert
ABSTRACT Energy is the second largest cost to a water utility, behind manpower, and it is forecast to significantly increase. Not only does the urban water cycle need energy to operate, it also contains both thermal and chemical energy. Researchers have identified that the urban water cycle in Amsterdam has enough potential energy to offset all of the greenhouse gas emissions presently emitted to operate it. One method used to recover this potential available energy is to extract heat from sewers. The first examples appeared in Europe over 30 years ago, and there are now over 500 wastewater heat pumps in use worldwide. Our challenge was to determine if heat extraction from sewers was both technically and commercially viable in Melbourne. It was found that while it would be technically feasible in Melbourne, it was, however, not presently commercially viable for the site tested. To make such a project commercially viable future natural gas price increases in the order of 260%, or market demand to offset electrical heating instead of gas, are needed.
INTRODUCTION A study of Melbourne forecasts that the energy required to provide water services into the future could increase by between 50% and 300% by 2045, depending on the form of urban development, residential water use and type of water supply adopted (Kenway et al., 2008). Not only will energy demand increase, energy market modelling undertaken for the water industry out to 2032 concluded that electricity prices for industrial customers in Melbourne could increase in the order of 1.5 to 2 times in the same period (SKM MMA, 2012). Not only does water need energy to be delivered, it also contains both thermal and chemical energy. Analysing
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the potential available energy in the water cycle of Amsterdam, van der Hoek (2012) identified that Amsterdam could achieve greenhouse gas neutrality for its operation if all of this potential energy could be recovered. One method already adopted internationally is to recover heat energy from sewers. The theoretical potential heat recovery from a sewer is about 12kW per litre per second of wastewater flow rate, assuming a 3Â°C temperature drop in the energy recovery heat exchanger. The first installations were built more than 30 years ago; the first example is at the Touring Club Switzerland in Emmen near Luzern, where a wastewater heat pump has been extracting energy from wastewater to heat the office buildings since 1979 (WWT, 2011). Today there are over 500 wastewater heat pumps operating worldwide, with heating capacities ranging between 10kW and 20MW (Schmid, 2008). CRM (2005) considers that a heat pump needs to have a heating capacity of at least 130kW for a sewer heat recovery project to be efficient and cost-effective. Smaller systems are possible; however, the unit costs of the system would be greater. Three options are presently used to recover heat from a sewer. A heat exchanger can either be installed into
Figure 2. Heat exchanger integrated into a sewer wall using Rabtherm Singen technology (WWT, 2011). the bottom of an existing sewer pipe (Figure 1), or a sewer pipe can be manufactured with the heat exchanger elements integrated into the bottom part of the wall (Figure 2). Alternatively, wastewater can be filtered and diverted into a separate pit containing a heat exchanger. The heat energy extracted from a sewer can be used for both hot water and space heating. To convert or upgrade this low-grade heat energy from a sewer requires an additional energy source to drive the heat pump, which can be either electricity or gas. A schematic diagram of the essential elements of an electric heat pump in heating mode is shown in Figure 3. The same installation can be used for space cooling and hot water production simultaneously, by rearranging the flow via valves. Figure 4 shows the schematic diagram of a heat pump in cooling mode. It should be noted that the wastewater is receiving the heat rejected from the heat pump in this mode.
Figure 1. Heat exchanger added to an existing sewer (Hamburg Wasser, 2011).
Although widely used internationally, no example of a sewer heat recovery project is yet operating in Australia.
Table 1. Preliminary assessment of potential sewer heat recovery sites. Diameter (mm)
Available power (kW)
Yearly energy (MWh)
No of times larger than YVW office annual usage
Industry development centre, School
Shopping centre, Commercial centre
Table 2. Heating and cooling demands for synthesised demand centres. Description
Floor area (m2)
10 storeys, 95 apartments
Open seven days for 17 hours
Aged care facility
50m pool, 25m pool, leisure play pool
Demand centre Residential complex
Accordingly, Yarra Valley Water has undertaken this investigation to determine whether it is both technically feasible and commercially viable in a business sense to extract heat from a sewer in Melbourne.
METHODOLOGY DESKTOP ASSESSMENT
Schmid (2008) suggests that the following conditions are required for a sewer to be viable for heat recovery: • It needs to have a sewer pipe diameter greater than 800mm; • The dry weather wastewater flow rate needs to be greater than 30L s-1; and • The water-covered surface at the bottom of the sewer needs to be at least 0.8m2.
Advice from Hamburg Wasser also suggests that the demand needs to be in close proximity to the heat exchanger, preferably within 200m. The amount of heat energy that can be extracted is then estimated for any wastewater flow rate, assuming the specific heat of wastewater to be a constant of 4.19 kJ kg-1 K-1, and selecting an acceptable temperature drop due to heat extraction (Aye, 2013). Adopting an average typical wastewater temperature in Melbourne, and allowing a temperature drop of 3°C, Yarra Valley Water identified its top five potential sites that closely match the conditions described. The annual potential heat energy available varied from 1,129 MWh to 14,871 MWh, as summarised in Table 1. To give the business a sense of the magnitude of the
potential heat energy, it was compared to the total energy used at its head office that accommodates approximately 600 employees. This comparison identified that the potential energy at the five sewer sites varied between two to 27 times as much as is used at the Yarra Valley Water head office. Identifying such a large heat energy potential warranted a more detailed assessment to determine if such an option was actually technically and commercially viable. TECHNICAL FEASIBILITY ASSESSMENT
To refine the preliminary analysis we wanted to determine if such a project was feasible in practice, considering annual variations in wastewater temperature and whether this could meet the actual annual heat energy or cooling demand variations in Melbourne. The Preston site, identified from the preliminary assessment as having the highest potential, was selected for the more detailed analysis. Part of the appeal was that the 28ha site is presently undergoing redevelopment, so potentially could offer cheaper integration options. It did, however, require hot water, space heating and cooling demand centres to be synthesised as we did not know what the eventual development would be.
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Figure 4. Electric heat pump in cooling mode.
Figure 3. Electric heat pump in heating mode.
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The technical feasibility study examined both the theoretical potential useful heat that can be obtained by recovering heat from the sewer, and the theoretical potential useful cooling that can be obtained by rejecting the heat to the sewer. Demand included the provision of hot water, space heating and space cooling. Alternative technology options available were considered, together with the method of heat distribution and impacts of heat extraction from the sewer.
Figure 5. Synthesised potential demand centres.
Climate data collated for a typical meteorological year for Melbourne (Morrison and Litvak, 1999) and the estimated annual heating demands were used to estimate the annual hourly demand profile. The heating load capacity demand profile for a typical week in July was adopted, while the heating season was selected to be between mid-May and mid-September. The maximum peak heating demand is estimated to be 0.85MW. The maximum peak cooling demand is estimated to be 1.3MW. The assumed cooling season was adopted to run between December and February. The cooling load capacity demand profile for a typical week in December was adopted. Transient system simulation modelling was then undertaken to quantify the potential heating and cooling that the chosen sewer could deliver. TEMPEST V1.01 (Durrenmatt and Wanner, 2008) and TRNSYS 17 software (Klein et al., 2012) were used. A typical water-towater heat pump with a nominal heating capacity of 2.3MW was selected for the analysis to determine the maximum possible environmental impacts, and the simulations run for a seven-day period for each season. COMMERCIAL VIABILITY ASSESSMENT
Figure 6. Variation in sewer temperature. We used this opportunity to synthesise
Sewer temperature variations at
a development comprising five different
the site were monitored and displayed
building types (demand centres), each
consistent variability throughout the
chosen to test different potential demand
monitoring period with temperatures
profiles. These included a 10-storey
varying between 13.1Â°C and 21.1Â°C,
residential complex, a cluster of 27
as shown in Figure 6. This does reflect
townhouses, a supermarket, an aged care
theory, which indicates that seasonal
facility and an aquatic centre. The design
soil temperature fluctuations decrease
details of each of these are summarised
with depth, stabilising at about 6m for
in Table 2 and are shown in Figure 5 to
clay type of ground (Williams and Gold,
highlight the physical proximity to the
1976). The sewer depth at this location
is approximately 6m.
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Costs were sourced for both capital expenditure and anticipated annual operations and maintenance costs. Capital costs included sewer heat exchangers, sewer installation, pipework, heat pump, circulation pumps, hot water heat exchangers, external heat pump plant room enclosure, and controls and monitoring. Operating costs were made up from electricity consumptions of the heat pump and circulation pumps, and system maintenance. Translating this notional development into an actual project would be anticipated to increase costs because factors such as road closures, disruption to existing services, engineering and design services, and
Table 3. Heating and cooling demands for synthesised demand centres. Demand centre
Hot water Space heating (MWh) (MWh)
Heat demand (MWh)
Space cooling (MWh)
Table 4. Average heat transfer capacity of heat exchanger for heating. Sewer diameter (mm)
Area of heat exchanger (m2/m)1
Heat transfer capacity (kW/m2)2
37.6 129.4 44.2
84.9 233.4 65.1
122.5 362.8 109.3
43.4 119.4 33.3
Aged care facility
Notes: CRM (2008) Assumed average specific heat extraction rate = 4 kW/m2; Rabtherm (2012)
5.8kW of heating per m length of sewer using this technology. The length of heat exchanger required if an electric heat pump is used with a 1MW heating capacity, with a 722kW heat extraction rate, is 125m. If a natural gas engine driven heat pump is used, the heat exchanger length can be reduced to 92m. IMPACT ON SEWERAGE SYSTEM
Figure 7. In-situ heat exchanger (Rabtherm, 2012). authority cost have not been included. A Net Present Value (NPV) assessment was undertaken of all costs, together with potential revenue streams.
RESULTS AND DISCUSSION TECHNICAL FEASIBILITY
The annual total heat demand (i.e. combined hot water and space heating demand) of the synthesised development is estimated to be 3,063 MWh, and the annual total cooling demand is estimated to be 768 MWh. The aquatic centre has the largest heat demand (64%), while the aged care facility has the largest cooling demand (37%). The distribution of load among different demand centres is shown in Table 3. The technical study identified that it was feasible to use the sewer as a heat source or heat sink. If a gas enginedriven heat pump was selected, which is more efficient at recovering heat energy than an electric heat pump, the potential annual total heat supplied could be up to 34,020MWh, of which 20,150MWh is recovered from the sewer (this compares favourably with the quick desktop analysis that estimated a heat energy potential of 14,871MWh).
The potential annual total cooling supplied was 15,460 MWh. The average heating capacities are 2.9MW and 3.9MW for an electric heat pump and gas engine driven heat pump respectively. The average cooling capacity is 1.8MW. Considering that the hot water and space heating demand, together with the space cooling demand of the synthesised development, are 3,063 MWh and 768 MWh respectively, and the peak demand capacities are 0.85MW for heating and 1.3MW for cooling, full heating and cooling of the development at the site could easily be achieved. The length of heat exchanger required has been estimated using data from CRM (2008) and sourced from a product manufacturer (Rabtherm, 2012). Rabtherm has a product that can be used for either heat recovery or heat rejection. A schematic diagram for a heating application is shown in Figure 7. The heat exchanger transfers heat from the wastewater and then supplies this to a heat pump for upgrading. The required heat exchanger length can be estimated using the average heat transfer capacities listed in Table 4. A 975mm sewer could expect a minimum heat transfer capacity of
Using a sewer for either heat extraction for heating or heat rejection to provide cooling will change the temperature of the wastewater in the sewer. Viability needs to be suitably designed so that there is no adverse impact on operating the sewer, and the downstream treatment plant. Schmid (2008) quotes the Association of Swiss Wastewater and Water protection experts recommending that the temperature of wastewater should not be reduced below 10°C at the point where wastewater enters the sewage treatment plant. In this case study the sewer is many kilometres from the sewage treatment plant, with many downstream inputs, hence there will be negligible impact on the sewage treatment plant. Locally, however, the temperature will drop to a minimum of 8.4° C at 2,000m downstream of the extraction point when 2.3MW of heat is extracted. It is well above the freezing point of sewage (approximately –2.5°C), therefore there will not be a risk of freezing the wastewater. When the wastewater is used for cooling, the temperature of wastewater is estimated to increase to about 26°C if the average heat rejection rate is 2.3MW.
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Multi-storey residential 24 x 1 bedrooms 57 x 2 bedrooms 14 x 3 bedrooms
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Table 5. Capital costs.
Table 6. Operating costs.
Sewer heat exchangers
Hot water heat exchangers
External heat pump plant room enclosure
Controls and monitoring
The total construction and installation cost for the proposed system (1MW with an electric heat pump) was estimated to be AU$1,710,100 and the annual operating cost was AU$154,454.
Details of capital and operating costs are listed in Table 5 and Table 6. Comparing this against the alternative heating option that uses natural gas, which is sold at 3.14 c/kWh, it is not presently economically feasible to operate a sewer heat recovery system of this size at this location. Natural gas prices would need to increase to 8.2 c/ kWh before it was economically viable. Alternatively, an option that may prove to be more economically viable would be a large heating or cooling demand centre that uses electricity rather than gas, as the cost of electricity is presently approximately five times that of gas for the same energy content.
Figure 8. Temperature difference between Melbourne and Stuttgart. Temperature data of Stuttgart has been shifted six months to allow the comparison. Table 7. Temperature differences between Melbourne and Germany. Temperature
Temperature ≤ 15°C
54% of year
76% of year
Temperature ≤ 10°C
28% of year
67% of year
A number of alternative options were investigated to determine if these would change the commercial business viability. These included reducing the sewer construction cost and including the value of the non-tangible benefits of such a project. An argument could be made to reduce the sewer construction cost if the heat recovery system were installed when a new sewer was laid, because it would not be an incremental cost. The non-tangible benefits were estimated to provide an additional
income of 2% of the project value for the first three years of operation and 1% of the project value for the two years after that. Both options were helpful in bringing the project closer to commercial viability, but neither was able to make the project commercially viable at this location. COMPARISON WITH EUROPEAN CONDITIONS
Sewer heat exchanger systems are successfully installed in many countries including Switzerland, Germany and Austria. We were, therefore, interested in quantifying the climatic differences between northern Europe and Melbourne to assess if this could be a large contributor to making such projects viable there and not here. It is presumed by the large number of systems already installed that they are economically feasible at these other locations. The ambient air temperature difference between Stuttgart, Germany and Melbourne has been used for this analysis. Temperature data of Stuttgart has been shifted six months and overlaid against Melbourne temperatures to allow a direct visual comparison. This is shown in Figure 8. The temperature differences have also been analysed to determine the proportion of time that the temperature in each city is less than 15°C, and less than 10°C. A summary is shown in Table 7. The countries where the sewer heat exchange systems operate successfully have a significantly colder climate than Melbourne. Not only is their seasonal heating period longer, but the temperature extremes are significantly lower than we experience in Melbourne. Therefore, they require more heating for a higher proportion of the year and greater quantities of peak heating demand. As a result, the heat exchange system is utilised for a longer period of the year and so improves the payback period of the initial investment. Another factor favouring the adoption of sewer heat recovery projects in Germany is the higher energy costs. Domestic electricity prices in Germany are double Melbourne prices, and
Table 8. Heat energy source comparison (Melbourne). Electricity
Prices (AU c/kWh), domestic supply, Germany (Source: Eurostat, 2012)
Prices (AU c/kWh), domestic supply, Melbourne
GHG Intensity (kg CO2-e/kWh), Victoria (Source: DCCEE, 2012)
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Technical Papers reticulated natural gas is approximately three times higher than in Melbourne (Table 8). These higher energy prices are relatively recent. Electricity prices increased three-fold between 2000 and 2011 (Jardin, 2012). Germany now also has Europe’s highest energy costs. In 2013, energy cost in Germany was also six times more expensive than in the United States (Wikipedia, 2013).
In Melbourne, the most economical heating energy is natural gas. This would clearly be the primary energy source to use at sites with a large heating requirement. Natural gas also has a significantly lower greenhouse gas intensity (Table 8). With the large difference between natural gas and electricity, had this project considered replacing an electrical demand, it would make such a project commercially viable. Therein also presents a future parameter that could make a sewer heat recovery of cooling project viable. Cooling is of particular interest, as cooling in Melbourne is normally provided from chillers driven by an electrical energy source. While potentially ideal, if a site could be found where electricity was to be replaced, an option analysis should also consider using natural gas to power a cogeneration or tri-generation plant. However, this does suggest that perhaps in locations where gas is not so readily available, such technology may have a feasible application.
CONCLUSIONS With increasing energy prices, the concept of recovering heat energy from a sewer is conceptually appealing. The method is widely used internationally but not yet in Australia. Various demand centres including an aquatic centre, supermarket, aged care facility, and high-density residential development were considered. The transient system modelling identified that recovering heat energy from sewers, or using this to provide cooling, is technically feasible. However, at this particular site in Melbourne it was not yet financially viable. This technology may prove more applicable in the following circumstances: • In areas where there is a higher heating demand;
rather than natural gas; • At a site that has a large cooling demand that is presently powered from electricity; or • If natural gas prices were to rise to approximately 8.2 c/kWh, from the existing 3.14 c/kWh.
CRM (see – Compass Resource Management Ltd) (2005): Sustainable Energy Technology and Resource Assessment for Greater Vancouver, Final Report, pp. x+80. CRM (see – Compass Resource Management Ltd) (2008): District Energy Consultation Paper, Prepared for: The District of Squamish, pp 1–52. DCCEE (see – Department of Climate Change and Energy Efficiency) (2012): Australian National Greenhouse Accounts: National Greenhouse Accounts Factors. July 2012. ISBN: 978-1922003-56-0. Dürrenmatt DJ & Wanner O (2008): Simulation of the Wastewater Temperature in Sewers with TEMPEST. Water Science & Technology, 57, 11, pp 1809–1815.
Francis Pamminger (email: Francis. Pamminger@yvw.com.au) is the Manager of Research & Innovation at Yarra Valley Water in Melbourne.
Hamburg Wasser (2011): Heat Recovery from Sewage Pilot Project Hamburg, Germany. Presentation delivered to Yarra Valley Water in March 2011 by Lueder Garleff. Jardin N (2012): Public Presentation at the International Water Association World Congress at Busan, Korea; Ruhrverband, Germany. Kenway SJ, Turner GM, Cook S & Bayness T (2008): Water-Energy Futures for Melbourne: The Effect of Water Strategies, Water Use and Urban Form. Water for a Healthy Country Flagship Report, CSIRO. October 2008.
David Scott (email: David.Scott@yvw. com.au) is a Planning Engineer in the Sustainable Development Group at Yarra Valley Water.
Klein SA, Beckman WA, Mitchell JW, Duffie JA, Duffie NA, Freeman TL, Mitchell JC, Braun JE, Evans BL, Kummer JP, Urban RE, Fiksel A, Thornton JW, Blair, NJ, Williams PM, Bradley DE, McDowell TP, Kummert M & Arias DA (2012): TRNSYS 17: A TRaNsient SYstem Simulation Program, Solar Energy Laboratory, University of Wisconsin-Madison. Morrison G & Litvak A (1999): Condensed Solar Radiation Database for Australia. University of New South Wales, Sydney.
Dr Lu Aye (email: email@example.com. au) is an Associate Professor and the leader of the Renewable Energy and Energy Efficiency Group, Department of Infrastructure Engineering, at the University of Melbourne.
Rabtherm (2012): Sourced from www.rabtherm. Accessed in June 2012. Schmid F (2008): Sewage Water: Interesting Heat Source from Heat Pumps and Chillers. 9th International IEA Heat Pump Conference, Switzerland. Paper No. 5.22, pp 1–12. SKM MMA (2012): Energy Price Forecasts 2013 to 2032. Report for the WSAA. 13 November 2012. Van der Hoek JP (2012): Climate Change Mitigation by Recovery of Energy From the Water Cycle: A New Challenge for Water Management. Water Science & Technology, 65, 1, pp 135–141. IWA Publishing, 2012.
Richard Jelbert (email: R.Jelbert@ndy. com) is a Senior Sustainability Consultant at Norman Disney & Young, Sustainability Group, Melbourne.
REFERENCES Aye L (2013): Heat Recovery from Sewers. Encyclopaedia of Engineering and Technology. Taylor & Francis.
Wikipedia (2013): http://en.wikipedia.org/wiki/ Energy_in_Germany. Accessed on 2 July 2013. Williams GP & Gold LW (1976): Ground Temperatures. Canadian Building Digests, Division of Building Research, National Research Council Canada, UDC 551.525, CBD180-180-4. WWT (2011): Taking the Heat Out. Water & Wastewater Treatment Magazine. 20 June 2011. (www.edie.net/library/view_article.asp?id=5 842&title=Taking+the+heat+out&source=5), Accessed on 19 July 2013.
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CRITICAL VARIABLES FOR A FAVOURABLE SEWER HEAT RECOVERY PROJECT
• Where electricity is used for heating
COMMUNITY-APPROPRIATE BIODIGESTERS FOR CAMBODIA A study of a viable sanitation option to address contamination issues in communities at Tonle Sap Lake
WATER SANITATION & HEALTH
Live & Learn Environmental Education Cambodia (LLEEC) and Engineers Without Borders Australia (EWB) are working on a two-facet approach to design anaerobic biodigesters for communities of Cambodia’s Tonle Sap Lake: controlled experimentation and community participation.
Cambodia’s Tonle Sap Lake is the largest lake in South East Asia and part of one of the most unique water systems in the world. Each monsoon season, as a result of the flooding of the Mekong Delta, the direction of the Tonle River reverses, resulting in an increase in the size of the Tonle Sap Lake from 2,500km2 to 15,000km2 (Mekong River Commission, 2010). This increase in size also creates a large variation in the depth of the water, with a change for the communities from floating communities to flood affected; this can be seen in Figures 1 and 2.
There are between 1.1 and 1.5 million people living in floating or flood-affected communities of Cambodia’s Tonle Sap Lake (Brown, 2010). Due to a lack of sanitation options, the lake is being contaminated by human and animal waste, as demonstrated by high localised concentrations of Escherichia coli (E. coli) in community water sources. Anaerobic biodigestion is one viable sanitation option to address this issue. Experimental data from biodigesters has shown a two-log reduction in E. coli (30 days’ retention time). Waste from approximately two pigs (6kg/ day) produced 285L/day of biogas in the LLEEC biodigesters. Community installations have also shown that families can replace part of their wood cooking needs with biogas. Additionally, the community installations provide critical user feedback to the technology development to ensure the community is strongly invested in the technology.
THE COMMUNITIES The lake is home to many floating communities who fish to sustain their livelihoods. There are no accessible and affordable sanitation systems for these extreme environmental conditions; standard options are inappropriate and there is little uptake from the communities. Limited sanitation options lead to community members usually urinating and defecating directly into their environment, contaminating water
sources that they use for drinking, food preparation, washing, bathing, and fishing. This problem has been compounded by the introduction of pig farms, often floating among the houses, resulting in pig waste passing directly into the community’s main water source. Results from water quality testing in Phat Sanday (Kampong Thom Province, Cambodia), localised within the community and the background environment, are summarised in Table 1. In both the wet and the dry season there are higher localised concentrations within the Phat Sanday community than in the background environmental samples. With constant casual exposure to the water, the public health effects of water contamination are likely to be significant.
THE NEED FOR A NEW DESIGN LLEEC began working with communities of the Tonle Sap around 2005; around 2008 the lack of sanitation was identified as a major problem. Other projects such as supply of clean water may have short-term benefits; LLEEC is taking a longer-term
The design team will continue to work on improving the technology.
INTRODUCTION WHAT IS A BIODIGESTER?
A biodigester is a unit (e.g. tank) designed to contain organic waste as it breaks down. If done in the absence of air, the biodigester is anaerobic and serves not only as a disposal route for organic (e.g. human and animal) wastes, but ideally also has the benefits of producing biogas for fuel and/or fertiliser which can be used by communities for local agriculture.
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Figure 1. A local school floating during the wet season.
Technical Papers TWO COMPETING AGENDAS To design a household-size anaerobic biodigestion system that will successfully be adopted by the community requires an understanding both of the technical aspects of the biodigesters and the community drivers, such as cost, appearance, ease of use etc, to adapt or reject a biodigestion system. To understand this and how they both complement and compete with each other the design team, after initial research and development, focused on a two-facet approach to devise a solution: 1.
Controlled experimental work; and
INITIAL RESEARCH AND DEVELOPMENT Figure 2. The school on land during the dry season.
After investigating appropriate options and finding that there were no suitable options available, Live & Learn in partnership with Engineers Without Borders Australia (the design team) began to develop their own solutions. Throughout the ongoing development of the initial sanitation option, a urine diversion desiccation toilet being developed in parallel, the community also identified the need for access to energy. One area of need was to replace their current fuel for cooking, which is predominantly wood harvested from the local forest. At the moment community members must travel to collect wood using time and resources; the wood also requires drying during the wet season, taking up space and time, and using the wood for cooking can create large amounts of smoke inside the cooking area. Anaerobic biodigesters address both of these issues and are successful in many rural communities; however,
on the Tonle Sap Lake in Cambodia their application is limited by both environmental and physical conditions and the feed requirements. Existing biodigesters are typically large, heavy and buried, and are therefore unsuitable for many conditions and applications. LLEEC, in partnership with EWB Australia, (the design team) and with funding from the Grand Challenges Exploration (GCE), an initiative of the Bill & Melinda Gates Foundation, are working to design and implement new systems suitable for application in these relatively extreme conditions. The design is a household-based system that can be easily operated and maintained by community members. The design allows community members to collect biogas to be used for cooking, as well as providing a potential source of fertiliser from the treated waste. The design will need to be technically and economically feasible as well as culturally acceptable.
Table 1. Mean E. coli and total coliforms testing by LLEEC 2009, 2010. E. coli (cfu/100mL)
Total Coliform (cfu/100mL)
Background environmental: Phat Sanday Commune Wet Season
Localised: Phat Sanday Commune Wet Season
Background environmental: Phat Sanday Commune Dry Season
Localised: Phat Sanday Commune Wet Season
Several pilot biodigesters were built, installed, and trialled both in the Live & Learn office and the Phat Sanday community, to get an initial understanding of technical aspects such as material availability and costs, and local construction methods, as well as community interest in the operation and application of systems. The successes and failures of this period helped narrow down to two preferred options.
METHOD: CONTROLLED EXPERIMENTATION In a semi-controlled environment, seven separate household-size anaerobic biodigesters were tested (Figure 3). Tests were designed to compare the biodigesters with different feeds, different retention times and different prototypes, in terms of gas production, pathogen reduction and ease of operation. The experimental work was undertaken with the Royal University of Agriculture Phnom Penh, and involved training of local students and potentially involving them further in the project after it is complete.
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approach to improve sanitation and water quality by filling a technological gap.
When considering the suitability of biodigesters LLEEC required further information on energy and waste management practices in the community, to inform the development of suitable designs. Extensive community engagement was important to assess understanding of biodigesters, of which few people were aware, and willingness to utilise such a technology. Furthermore, a range of design options was discussed in detail to help guide the design development, and key community representatives were involved in the production and installation of initial pilot systems.
Figure 3. The controlled experimentation site and the team.
Figure 4. A modified HDPE tank biodigester.
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During the design development there were a number of different prototypes considered, ranging from small systems created from a car tyre inner tube, to larger systems created from polyethylene sheet plastic. Two prototypes chosen for the technical testing were:
Figure 5. A polyethlyene tube biodigester.
A modified HDPE 500L tank (normally used in Cambodia as a water tank), as shown in Figure 4.
A polyethylene tube biodigester (materials commonly available around Cambodia). Figure 5 depicts this biodigester; the red and white plastic seen in the photograph is plastic sheeting used to protect the plastic used for the biodigester body from UV degradation.
Three different feeds were tested (Table 2): • Feed 1 Solely pig waste (supplied from a local pig farm). There is a large amount of pig waste in the communities, which has a large potential as a feed source for the biodigesters. • Feed 2 A mixture of pig waste and water hyacinth (a weed prevalent on the Tonle Sap, Carlsson et al., 2013). The water hyacinth was tested to act as an additional feed source in case there was insufficient waste present. (Water hyacinth is shown in the foreground of Figure 6).
Figure 6. Water hyacinth in Phat Sanday Commune, Kampong Thom Province, Cambodia.
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• Feed 3 A mixture of human and pig waste. Feed 3 tested one of the anticipated uses of the biodigester, which was to treat both pig waste
Table 2. Summary of biodigester test conditions. Biodigester
Retention Times (days)
and human waste in one biodigester; the pig waste will provide enough of a feed source to ensure a large production of gas, but also sufficiently treat the human waste. DIFFERENT RETENTION TIMES
METHOD: COMMUNITY PARTICIPATION As mentioned, Live & Learn has been working with these communities for a number of years and has a number of key community members with whom they work closely to gain greater community insight. Prior to installation of biodigesters in the community, a series of educational sessions was
There was more initial interest from the communities in flood-affected areas; there was some hesitation within the floating communities where there were no previous examples of biodigesters within their community. However, once they saw the biodigester in operation they were interested in having one. The community is mainly interested in the gas production, followed by an interest in the bioslurry (the output from the biodigester).
RESULTS AND DISCUSSION COMMUNITY UPTAKE â€“ DO PEOPLE WANT TO USE IT?
Figure 8 shows some initial data from the pilot testing stage. It is difficult to draw significant conclusions from this preliminary data in terms of long-term usage, although useful to help frame discussions around reasons people in the community may not use the biodigester.
Once initial interest was garnered, the design team installed a number of biodigester systems within several different target communities to appreciate community understanding and interest in the biodigesters. Initially prototypes installed were the same as those tested in the controlled experiments; however, over time some changes were made due to community acceptance, as explained in the Results and Discussion section. Of the 30 installed biodigesters, 28 were manufactured from HDPE tanks (Figure 7) and two were polyethylene tube. Initial preference of the community appeared to favour the hard plastic, which could explain the difference in the number of hard and soft plastic installations.
Figure 7. An HDPE tank in Phat Sanday community.
Information about community interest and potential uptake was also gathered. As this is an ongoing design process, more feedback is expected to be gathered throughout the process. This feedback will be used by the design team to modify the biodigester design and improve community acceptance of the solution. Some minor changes to the design have already occurred and are discussed in the Results and Discussion section.
These installations have provided some information, both qualitative and quantitative, about community perceptions. Local people were asked to provide monthly reports about the success of the biodigesters, their operation, gas production, and regularity of feeding. This in turn was supplemented by ongoing field visits by the design team to see the biodigesters in operation.
Figure 8. Pilot testing data. SEASONALITY
Life on the lake is made up of wet and dry seasons, pig farming season, fishing season etc. At the time of data collection, there were nine people not using biodigesters. This is because pig farming was not in season; without pigs there is a limited feed source for the biodigester. This is why the design team is looking at other feed source options to enable people to continue to feed the biodigester and produce gas. Some of the options include wastes from the house and community. i.e. fish waste, human waste and water hyacinth.
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Three different retention times of approximately 30, 60 and 90 days were tested (Table 2); Lam et al. (2009) state that ideal retention times for biodigesters vary between 30 and 100 days. Increases in retention time result in an increase in the biodigester size and subsequent cost. Testing at these different ranges was aimed at understanding the additional benefits of longer retention times, and whether that will outweigh the increase in size and cost.
held. Commune and village meetings aimed to inform the community about biodigesters, their use and benefits, then more informal meetings between key community members and other people allowed interested community members to offer to have a pilot site at their house.
During these field visits the design team members also conducted conversations with the biodigester users, which provided informal feedback. Some field visits also included training sessions for the community members where they learnt how to construct the biodigesters, so ongoing maintenance could be carried out by the users themselves.
Technical Papers Although early tests have incorporated the learnings from some of these investigations, there is still a need for further research, to demonstrate that a biodigester can produce enough gas for the family using alternate wastes such as a mixture of human waste and water hyacinth. During the fishing season it is also difficult for community members to be able to feed the biodigesters every day, as often they will go away for days at a time before returning home. GAS PRODUCTION – CAN IT PROVIDE FOR A FAMILY?
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The results obtained regarding gas production demonstrated variations from day to day. The main reason for this variation was the method of gas production measurement (gas production was measured by displacement); some other slight daily variations may have resulted from changes in temperature and temporary blockages within the system. Figure 9 shows the average daily gas production for each of the biodigesters.
Figure 10. Biogas cooking for field installations. DOES BIGGER MEAN BETTER?
Figure 9 also shows that an increase in gas production is achieved for longer retention times (or increasing size of the biodigester). Biodigesters 5 and 6 with the longest retention times (90 and 60 days respectively) produced the highest mean daily gas volumes. Figure 11 plots three different-sized biodigesters (Biodigester 1: 400L; Biodigester 5: 800L and Biodigester 6: 1200L) all fed the same daily feed, and shows that there appears to be a non-linear relationship between size and gas production.
Figure 9. Mean daily gas production over three months for the seven biodigester conditions (Table 2). Results indicated that approximately 285L of cooking gas was produced when the biodigester (Biodigester 3) was fed with 6kg of pig waste in an approximate 1:1 ratio of waste to water (7kg of water), and with a retention time of 30 days. According to the National Biodigester Programme (2011) this should equate to about an hour of cooking a day. While this is not enough to replace all of a family’s cooking needs, it is a partial replacement (Carlsson et al., 2013) and families can reduce their reliance on wood (reduction of deforestation, including of flooded forests that are an important fish habitat, has been a key secondary objective of the project). Similar results were obtained for each of the different feeds, although slightly higher gas production was obtained for the mixed feeds in comparison to the sole waste (Biodigesters 4 and 7). Each of the three feeds was deemed suitable for use in the biodigesters. It is important that the ability to use different feeds in the biodigesters and still yield similar gas production is confirmed for the technology so we can educate those in the community about the benefits. Community data also provides some information around cooking time (gas production is difficult for community members to estimate). Figure 10 shows the data received from the field in terms of cooking, while the black bars show the variation in the data received. Using a conversion of 400L of biogas for one hour of cooking (National Biodigester Programme, 2011) in Figure 10 we can compare the gas production achieved in the controlled experiment (shown in blue) with data from the field. The similarity provides some assurance that the data collected in the experiments can be repeated in the field.
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Figure 11. Biodigester size vs. mean daily gas production. This is important to note and consider when designing systems for the community, given that availability of gas was one of the main objectives of the biodigesters. However, the increase in gas production should be balanced against the extra volume needed to achieve the extra retention time. Figure 10 shows that doubling the size (and thus retention time) from a 400L to 800L biodigester does not result in twice the amount of gas, despite having twice the footprint. At this stage of the design process the design team has concluded that the extra cost associated with increasing size is not worth the additional gas benefit, and is aiming to build systems with a retention time of approximately 30 days. More detailed cost-benefit analyses are being prepared to help estimate the long-term gains relative to the investments in biodigesters of different sizes and designs. REDUCTION OF FAECAL INDICATORS – REDUCING LOCALISED IMPACT
Most of the seven biodigesters tested in the controlled experiment achieved a two-log reduction in both E. coli and total coliforms (Figure 12 and Figure 13 respectively), with the exception of Biodigester 7. This reduction removes 99% of faecal indicators that would otherwise go straight into the lake; this is one of the few viable options available for removing pathogens from the lake and reducing the presence of localised concentrations of E. coli. The design does not entirely eliminate the addition of faecal
Figure 12. E. coli reduction – controlled experimentation.
Figure 13. Total coliforms reduction – controlled experimentation.
indicators from the community to the lake – the ideal technical solution – but this technical optimum needs to be balanced by creating a solution feasible within the contextual and financial constraints. However, if the design is appropriately adopted the addition of faecal indicators to the lake with biodigesters is 100 times lower than without biodigesters (Carlsson, 2013).
to produce gas immediately. As such, there is opportunity to reduce the initial amount of fill waste placed in the biodigester, thus decreasing the period where reduction is not possible and improving E. coli and total coliform reduction.
During this experiment it was not possible to assess the ability of the biodigesters to remove parasite (Ascaris sp.) eggs; due to the lack of local laboratory capacity these could not be tested at the time. However, these tests are now being addressed by other experiments the design team is currently undertaking. A longer retention time may be needed to achieve destruction of these eggs; and information from this work will also feed into future design improvements. If the longer retention time results in the destruction of parasites, this additional benefit may outweigh the additional cost associated with design improvements. IMMEDIATE FEEDBACK – WHEN DOES THE GAS START?
It is important for a user to see visible results when using a new technology. In the case of the biodigesters, immediate feedback that draws them to want to use the biodigester is the production of gas for cooking. When installing biodigesters in the community, the biodigesters are often filled with a large volume of waste; although this waste will not undergo the full biodigestion, it creates conditions in the biodigester conducive to rapid initial gas production. The controlled-experiment biodigesters were filled with less waste initially as this meant that all the waste placed in the biodigester stayed there for the entire retention time, and thus a 99% reduction of E. coli and total coliforms could be achieved. Filling community biodigesters with a large amount of waste leads to a short period, approximately equal to the retention time of the system (30 days), during the start-up when this reduction may not be achieved. There is a need to find a balance for the installations in the community, ideally so gas production and reduction in E. coli and total coliforms both begin soon after biodigester installation. As awareness of biodigesters grows in the community, people need less reassurance of the biodigesters’ ability
The principle of easy local operation and repairs has driven much of the selection of materials and construction techniques, and the community installations have also provided further information about how the material selection fares under the local conditions. Within the floating communities the houses and, subsequently, the biodigesters are subjected to waves from passing boats and also large storms. Throughout the design process some minor changes based on feedback from the community have resulted in changes to the biodigester design. In design there is often a trade-off between design functionality and cost; involving users in the design process introduces a new aspect of trade-offs between technical design (aiming for best value) and user perceptions. One example of this design process is the soft plastic biodigester. The regular polyethylene was replaced with a fibre-reinforced plastic, due to community concerns. Users felt more confidence in the durability of the fibre-reinforced plastic, which also added some weight to the system, creating a modest pressure on the gas, making it easier to cook with. The feedback from the community highlighted to the design team that keeping the costs as low as possible while still remaining functional was not as important to the community as some concerns.
CONCLUSIONS The anaerobic biodigesters were able to achieve a two-log (99%) reduction of E. coli and produce gas to allow families to partially replace their firewood with biogas. These prototypes also create an opportunity for the communities to improve their sanitary conditions. Undertaking the experiments in a controlled environment allowed the design team to understand the best ways for the system to be operated. However, these systems will not always be operated under ideal conditions. Community members, the biodigester users, will be incorporating the operation and feeding of these systems into their regular lives
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The differences in feed, retention time and prototype seemed to have little impact on the pathogen reduction. This can be seen as positive, as it means the options we are presenting to the community provide them with robust alternatives to defecating into the lake and will provide treatment to their waste.
BIODIGESTER OPERATION AND MATERIALS
Long-term success of the technology is likely to depend on the ability of community members to be able to fix the biodigesters themselves. Training of local community members has been well attended by a wide range of community members, and designed to be as participatory and practical as possible.
Technical Papers and, as such, have priorities outside of ensuring optimum operation of the biodigester.
WATER SANITATION & HEALTH
Thus there is a need for identification of the key, broad parameters under which the biodigesters can operate successfully; even if these might not be the optimum conditions for maximising gas production or reduction of E. coli and total coliforms. A balance must be struck between achieving optimum results with the biodigester and the practicalities of operation. If it is not easy to incorporate biodigester operation into the daily routine, then it will not be sustainable in the long term. So far installations within the community have provided inputs into the design. These inputs make the design more suitable for individual household needs and improve the potential marketability of the biodigesters. Installations at the moment have required in-kind donations from community members, i.e. assistance with construction; in the future it is hoped that the benefits associated with the biodigester will provide enough incentive for people to purchase the biodigester of their own accord. Financial sustainability is also a requirement for long-term implementation.
ONGOING AND FUTURE WORK ANIMAL-FREE OPERATING REQUIREMENTS
As animal ownership is low in these communities, Live & Learn is also determining the operational requirements for the biodigesters intended for use without animal waste, instead utilising human waste and water hyacinth. The water hyacinth may be critical to ensure sufficient gas production to make the systems economically feasible for households with no additional animals. DESIGN IMPROVEMENT & SECONDARY TREATMENT
The biodigesters at this current stage achieve a two-log reduction in E. coli; however, the design team thinks that there may be cost-effective ways to improve their performance further. The design team is partnering with a Cambodian social enterprise called “Wetlands Work!” to further treat the biodigester output using their “HandyPod” (Figure 14). Pods offer further anaerobic digestion followed by aerobic treatment of the bioslurry
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Fisheries (MAFF) and the Netherlands Development Organisation (SNV), which has been involved in a wide rollout of biodigester in many provinces (the Cambodian equivalent of States). Through these partnerships the design team aims to make this innovative technology accessible to many more vulnerable communities and improve sanitation and energy access.
ABOUT THE ORGANISATIONS Figure 14. A ‘HandyPod’ attached to a floating house in Pursat Province, Cambodia. through the use of the highly active microbial mesocosm enabled by an extensive surface area of water hyacinth roots. Pods are currently being developed as a wastewater treatment option for floating communities. FURTHER COMMUNITY FEEDBACK
The design of these biodigesters is not yet final. The installations have only been in the community for six to 12 months. The lifespan of the biodigesters is expected to be 10 years for the hard plastic biodigesters and, as such, it will be important to monitor and continue to understand community views and values with regard to the biodigesters over the coming years. This feedback loop will continue to make improvements to design, in a similar way to those mentioned above, but community feedback will also be sought in the future by more formalised workshops. DIRECT TOILET CONNECTIONS
The design team will soon be connecting toilets directly into the biodigesters. This process will be another portion of the design process that will rely heavily on community input, but will also bring technical challenges of its own, particularly for floating communities. This next step is vital for ensuring consideration of the biodigesters as a sanitation solution for human waste. SCALING UP
The next stages for the biodigester are primarily to increase usage in the communities it was designed for, those living on and around the Tonle Sap, through establishing sustainable distribution mechanisms. Live & Learn is working with the Cambodian National Biodigester Programme, a joint program between the Cambodia Ministry of Agriculture, Forestry and
Engineers Without Borders Australia (EWB) is a member-based, not-for-profit organisation with 10 years’ experience in creating systemic change through humanitarian engineering. To find out more about EWB and how you can support this work visit www.ewb.org.au. Live & Learn Environmental Education’s vision is for a sustainable and equitable world free from poverty. For more information on LLEE please visit www.livelearn.org.
FURTHER INFORMATION For further information on the project please contact: Rob Hughes – WASH Manager, Live & Learn Environmental Education, email: rob.hughes@livelearn. org or visit www.livelearn.org
THE AUTHOR Gabrielle McGill (email: firstname.lastname@example.org) spent one year working at Live & Learn Environmental Education as an Engineers Without Borders Australia (EWB Australia) volunteer. She currently works at GHD as a Process Engineer – Water and continues to volunteer with EWB Australia from Sydney, Australia.
REFERENCES Brown M (2010): Sanitation in Floating Communities in Cambodia. Available from Live & Learn Environmental Education, Cambodia. Carlsson H & Kiste K (2013): Environmental Sustainability of Floating Biodigesters in Tonle Sap Cambodia. Master Thesis, Lund University. Lam J, ter Heege F & Teune B (2009): Postgraduate Programme Renewable Energy, University of Oldenburg. Mekong River Commission (2010): Mekong River Commission, Vientiane, Laos. Viewed 12 August 2013, www.mrcmekong.org/themekong-basin/physiography/physiographicregions/ National Biodigester Programme Cambodia (2011): Information Folder. Available from National Biodigester Programme.
DECAY OF HUMAN ENTERIC PATHOGENS IN AGRICULTURAL SOIL AMENDED WITH BIOSOLIDS Key findings from a comprehensive research project to examine potential health risks K Schwarz, S Toze, D Pritchard, JPS Sidhu, Y Li
Biosolids are a valuable resource that can be used sustainably as a soil amendment to improve the chemical and physical properties of soil. The application of biosolids onto agricultural land introduces substantial organic matter and is a rich source of plant-available
The environmental impacts associated with the use of biosolids as a
1996) ET AL.,
Although properly treated biosolids are a safe and effective fertiliser, any pathogens present may contaminate foods produced from the field. Awareness of potential health hazards associated with biosolids in agriculture has long been acknowledged, however, for better management of health risks, quantitative data on pathogen numbers and survival potential in the environment is required (Gerba and Smith, 2005).
Minimal data has been collected on the fate of human viruses in the soil, particularly where cereal crops are grown. In the process of identifying potential human health risks, three key areas were identified where contact with pathogens may occur; thus the research objectives were to assess the decay of enteric pathogens: i) in the biosolids-amended soil where cereal crops are grown; ii) in the plant phyllosphere (leaves and
Keywords: biosolids-amended soil, agriculture, adenovirus, phyllosphere, bioaerosols, wheat grains and cereal crops.
Approximately 360,000 dry tonnes of biosolids are produced in Australia annually and the bulk of these biosolids (60â€“70%) are applied to agricultural land for beneficial purposes, particularly as fertiliser to amend nutrient-depleted soils (LeBlanc et al., 2008). However, biosolids are known to contain a diverse range of human pathogens such as adenovirus, norovirus, Salmonella enterica, Cryptosporidium and Giardia (Sidhu and Toze, 2009).
fertiliser need to be evaluated in the interest of protecting public health from transmissible diseases, since there is currently no monitoring system in place to track pathogen decay following the application of biosolids onto land (Gerba and Smith, 2005). The major direct sources of exposure risks are municipal wastewater treatment plant workers, biosolids handlers, onsite treatment systems, biosolids application sites and animal feeding operations (Figure 1). Land application of biosolids may also generate bio-aerosols (Gerba and Smith, 2005), airborne particles containing living microorganisms such as pathogens.
BIOSOLIDS & SOURCE MANAGEMENT
The results of this study suggest that the target microorganisms decayed faster in the biosolids-amended soil compared with the unamended soil in the field, that the decay times were specific to the microorganism type; and that microorganism decay was correlated to declining soil moisture levels and increasing soil temperature. The risk of transmission of disease-causing microorganisms (human pathogens) from cereal crops fertilised with biosolids was considered to be low.
nutrients and trace elements (Joshua et al., 1998; Epstein, 2003; Horan et al., 2004; LeBlanc et al., 2008). Several studies have shown the many benefits to agriculture such as increased crop yields, improved soil fertility, soil conditioning, improved cation exchange, an increase in soil porosity, decreased bulk density and increased soil water-holding capacity (Epstein, 1998; Nicholson et al., 2005; LeBlanc et al., 2008).
ABSTRACT A comprehensive study was undertaken to examine the survival potential of enteric microorganisms in biosolidsamended soil, wheat plant phyllosphere, and stored grains. The presence of these microorganisms in the dust at harvesting time was also evaluated. In situ field experiments were conducted to examine the decay of E. coli (indicator bacteria), Salmonella enterica, bacteriophage MS2 and human adenovirus in biosolidsamended soils and in dust generated during harvesting of wheat. Glasshouse experiments were conducted to determine the survival potential of enteric microorganisms in the wheat phyllosphere and stored grains to determine any possible risks to humans or livestock through consumption of contaminated grains or fodder.
Figure 1. Potential pathways through which human pathogens in biosolids could be ingested by humans.
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Technical Papers spikelets or grain heads) where contact with contaminated parts may occur in handling and consumption and; iii) the background bacteria levels present in the field at biosolids-applied sites where inhalation or contact with contaminated aerosols or dust may occur at harvest time. Enteric microorganisms were laboratory-cultured and then inoculated into the soil, wheat phyllosphere, grains and matured wheat stems. The change in numbers of seeded microorganisms was then monitored over time to obtain the estimated decay time for a one-log reduction of pathogen count (T90 values) to occur under ambient environmental conditions. This paper reports on the key findings from a comprehensive research project designed to examine the potential health risks from biosolidsamended soil, pathogens surviving in plant phyllosphere, stored grains and in the dust at harvesting time.
without the loss of bacteria and viruses from the chambers. Individual chambers were filled with 25% biosolids to 75% soil collected from each site. The chambers (120) were placed into the topsoil at the beginning of the crop-growing season. Control chambers were also set up using soil only (unamended).
Figure 2. A commercial 3.5mL Microsep™ centrifugal device (35mm x 10mm) used as a sentinel chamber; and (bottom right) filled with the sample contents of soil, biosolids and laboratory-cultured microorganisms.
MATERIALS AND METHODS
BIOSOLIDS & SOURCE MANAGEMENT
SOIL DECAY EXPERIMENTS
Three field sites for broadacre wheat (Triticum aestivum) cultivation were established in Moora, Western Australia (WA) and Mt Compass, South Australia (SA). Soil at each site was amended with biosolids according to the nitrogenlimited biosolids application rate (NLBAR) as 1 x NLBAR at Moora in 2006 and 1.5 x NLBAR at Moora and Mt Compass in 2008, as determined by Crute (2004), according to district practice (DEC, 2012), to create normal external environmental conditions. Thus, application rates at the Moora sites were 6 t dry solids (DS) ha-1 in May 2006, and 19 t DS ha-1 in May 2008 (using airdried biosolids from Bolivar Wastewater Treatment Plant (WWTP) at 66% moisture to 1.8% solids), and at Mt Compass, 28 t DS ha-1 in May 2008 (using anaerobically digested biosolids from Beenyup WWTP at 20% moisture to 7.7% solids). Topsoil (0–10cm depth) collected from each site was mixed with biosolids from the nearest wastewater treatment plants (i.e. Beeynup, WA and Bolivar, SA) and inoculated with laboratory-cultured E. coli, S. enterica, bacteriophage (MS2) and adenovirus as described in Schwarz et al. (2010). Then amended soil was placed into sentinel chambers (Figure 2). The constructed sentinel chambers with membranes (0.2 μm pore size) on both sides were sufficiently large to allow exchange of gases and moisture
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Figure 3. Wheat crop at harvest time at the Moora site in WA. The pink tags mark the location of buried sentinel chambers. Replicate chambers (three) were collected fortnightly from each site (Figure 3) to week four, then at monthly intervals up to seven months (the duration of the wheat-growing season) or until target microorganisms fell below the detection limit. Soil moisture levels were also monitored inside and outside the chambers using oven-drying and automated tensiometers. Daily air temperature and other climatic variables were recorded using Tinytag Plus 2 monitors. PHYLLOSPHERE AND GRAIN EXPERIMENT
Wheat plants were grown in pots in the glasshouse using soil from Moora, WA. The spikelets (grain heads) and leaves of wheat plants were inoculated with E. coli, S. enterica and bacteriophage MS2 at flowering stage as described in Schwarz et al., 2013. Plant leaves and spikelets were sampled hourly for up to nine days. Samples were processed within
24 hours of collection in the laboratory using phosphate buffer, processed in a stomacher (laboratory paddle homogeniser) and plated onto agar as described in Sidhu et al. (2008) to quantify microorganisms. For the grains experiment, two grain varieties – biscuit wheat (ASW) and pasta wheat (NN) – were inoculated with E. coli, S. enterica and bacteriophage MS2 using an atomiser. Grain samples were stored in tins with the lids on to represent grain silos. Samples were collected daily for up to 35 days. Grain samples were suspended in phosphate buffer, processed in the stomacher and plated onto agar, as described in Sidhu et al. (2008). COLLECTION OF HARVESTER DUST SAMPLES
The dust experiments were carried out over two years (2008 and 2009) at Moora, WA, at four cropping sites during harvest time. Biosolids had been previously applied to the first site in May 2006 (three years earlier) and the second site in May 2009 (seven months earlier). No biosolids were applied to the nil-biosolids sites. Ambient air samples were collected and tested for the background levels of bacteria present at the site (E. coli, enterococci and heterotrophic bacteria) using SKC BioSamplers® with Vac-U-Go pumps. No experimental spiking was carried out for this study. Samples were taken downwind from the operating axial-flow harvester. At each site, soil, spikelet, chaff and grain samples were also tested for the background bacteria (as mentioned above). Samples were analysed within 24 hours of collection on selective agar plates, as previously described. WHEAT AND GRAIN SAMPLING FROM THE THRESHER
A separate experiment with a thresher was carried out in an undercover area (Northam, WA) to determine the effect of threshing on microorganism numbers. Pathogens could transfer from contaminated biosolids-amended soil onto wheat plants during threshing and avert a health risk at harvest either from contact with bio-aerosols or from consumption of contaminated grain products. Matured wheat was sprayinoculated with E. coli, S. enterica and bacteriophage MS2 using an atomiser for a more controlled experimental environment. The wheat plants were fed into the thresher and plant parts
Technical Papers RESULTS
Table 1. Time (T90) for a one-log10 reduction to occur for enteric microorganisms in the soil, from the phyllosphere and from stored grains.
Key findings from the soil experiments were:
Estimated T90 times (days)
Grains – noodle
• Decreasing soil moisture and increasing soil temperature significantly influenced most microorganisms at Moora (P<0.05) and Mt Compass (P<0.01) in 2008, particularly in the unamended soils (Figure 4). Increasing soil temperature also influenced E. coli decay at Moora in 2008 in both soils. Key findings from the phyllosphere and grains experiments were:
(spikelets, chaff, grains and dust) sampled to quantify microorganism numbers.Samples were suspended in phosphate buffer, processed in the stomacher and plated onto agar plates to quantify colony-forming units (cfu) or plaque-forming units (pfu), as described for the soil and grains experiments. DATA ANALYSIS
Pathogen counts were normalised into log10 cfu or pfu g-1 from the raw data. Origin® 6.1 was used to perform standard deviations, trend lines and logarithmic transformations. ANOVA was used to identify sources of variation (i.e. site, treatment) affecting final pathogen counts (log10 Count) and all analyses were performed using SAS 9.1. Based on the decay rates for either ‘biosolids’ or ‘nil’ treatment in the soil experiments, the decay time for a one-log reduction of pathogen count (T90 values) was estimated using quadratic equations (Schwarz et al., 2010).
Log10 pfu g dw
0 100 120 140 160 180 200 Time (days)
Figure 4. Decay patterns of spiked microorganisms in biosolids-amended soil (chambers) at the Moora site in 2008, with soil moisture patterns (in chambers) and soil temperature.
Soil moisture (%) and soil temperature C
Log10 cfu g ds
6 5 4 3 2 1 0
80 100 120 140 160 180 200 Time (hours)
Figure 5. Decay pattern of virus (MS2) on spikelets (◊) and leaves (t) of wheat. • The grain variety made a significant difference to the decay times of the target microorganisms. The microorganisms on the biscuit variety of grains (ASW) persisted significantly longer than those on the pasta variety (NN) (Figure 6); • The bacteria spiked onto stored grains had shorter decay times (Table 1) than the bacteriophage MS2, which persisted longer than the bacteria. Key findings from the harvesting experiment were: • Total heterotrophic bacterial levels were highest on the chaff, especially at the unamended site. The same bacteria in the dust and air were higher at the biosolids-amended site than at the unamended site; • No E. coli was detected in any of the samples in 2008; however, low levels of enterococci were detected in dust samples in 2009 where biosolids had been applied seven months earlier. These levels were slightly higher at the biosolids-amended site (2.71 x 103 cfu per m3), but not statistically significant; • Total heterotrophic bacterial numbers were higher in the dust samples during harvesting than in the clean air where no
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E. coli Salmonella MS2 Adenovirus Soil temperature Soil moisture
• The location of the microorganisms on the plant made a difference to decay times. The microorganisms on the spikelets decayed faster than the microorganisms on the leaves, although this was not statistically significant (Figure 5);
An ANOVA (linear) was applied and T90 values were estimated for phyllosphere, grains (Schwarz et al., 2013) and thresher experiments. 9
• Microorganism type influenced decay times, i.e. bacteria spiked onto the wheat plant had shorter decay times than the bacteriophage MS2;
To determine any relationship between changes in soil temperatures or soil moisture (within individual microorganisms), correlations were calculated using the CORRE function (Excel) and any significance determined using Student t-tests (P-value at 0.05). A one-tailed Student t-test was used to determine any significant differences between the soil moisture levels in the chambers and the soil outside the chambers.
• Most of the target microorganisms (apart from adenovirus) decayed faster in the biosolids-amended soil than in the unamended soil (Table 1) and could not be detected in the soil after six to seven months (Figure 4);
Technical Papers For example, in Western Australia 8 the minimum pathogen grade for 7 direct land-applied 6 biosolids for use in agriculture (P3 for 5 non-root crops) is 4 2,000,000 thermotolerant coliforms 3 (DEC, 2012). While 2 these levels are the guideline 1 values, they do 0 not represent the 0 10 20 30 40 50 60 70 whole suite of Time (days) pathogens that Figure 6. Decay pattern of S. enterica on pasta variety (n) may be present and biscuit variety (o) of wheat. in any batch of harvester was in operation; and biosolids. Moreover, no data is available on the individual • In the field, heterotrophic bacterial survival times or the types of the numbers were highest on the chaff pathogens present in sludge (or biosolids). samples. This information is important for Key findings from the thresher land application of biosolids since some experiment were: viruses, helminths and protozoa have been • The spiked microorganisms were reported to persist in the soil for longer higher on chaff than the grains than bacteria (Sorber and Moore, 1987; after threshing; Sidhu and Toze, 2009). Efficient processes to remove high levels of pathogenic • Low levels of E. coli and bacteriophage contaminants at treatment plants, along MS2 passed through the thresher into with recognised rates of inactivation once the dust samples. S. enterica was not introduced into the soil, can decrease able to be detected in the dust after the risk of transmission of diseasethreshing; and causing microorganisms and optimise the opportunities for biosolids reuse. • Bacteriophage MS2 numbers were more stable than bacteria throughout In the present study, a general trend the process of threshing. As a result, was observed where the decay of the numbers were higher on the grains target microorganisms was higher in the and chaff following threshing. biosolids-amended soil, thus indicating that biosolids application to agricultural DISCUSSION land may have a positive influence on the Natural attenuation of enteric natural decay of pathogens in the soil. microorganisms in biosolids-amended The decay times (T90) of enteric bacteria soil can provide a barrier to the potential inoculated into biosolids-amended soil transmission of human diseases in a multiin the field were four to 12 d for S. barrier risk management approach. This, enterica (at Moora, WA) and five to seven in turn, can influence the permissibility for d for E. coli at Moora in 2006 and Mt biosolids to be applied to agricultural land. Compass, SA in 2008 (Table 1). Similar The reduction of pathogen numbers T90 decay times of four d for E. coli and during sludge treatment is essential 12 d for enterococci were reported in in a multi-barrier approach of risk our previous study by Crute (2004) in management, along with the crop types biosolids-amended soil at Toodyay, WA. to which biosolids are applied (i.e. highIn comparison, one-log10 reduction times risk crops consumed raw, or low-risk of 15 d for E. coli and 10 d for Salmonella crops consumed following processing). have been reported in soils irrigated with Currently, the level of pathogenic farm effluent in a study from Victoria contamination in biosolids is graded (Chandler and Craven, 1980), and eight according to indicator bacteria numbers. to 15 d for S. enterica in a column study The extent of microbial contamination with sewage sludge amended soil from and resulting grading may currently restrict New Zealand (Horswell et al., 2010). The maximum time before the microorganisms the possible end uses for the product.
BIOSOLIDS & SOURCE MANAGEMENT
Log10 cfu g dw
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fell below the detection limit in this study was well within the time taken for the crops to grow and be harvested (i.e. <3 to 4 months). Based on results from the present study, the main microorganisms of concern are the enteric viruses, since they showed slower decay patterns than bacteria in the biosolids-amended soils (T90 of 22–180 days for bacteriophage MS2 and >180 days for adenovirus). In Australia, the growing season of cereal crops is approximately six months from seeding to harvest, and grain crops are generally not consumed raw. Therefore, the risk of transmission of disease-causing microorganisms from biosolids-amended soil can be considered to be low, based on these reported decay patterns. In addition, the climatic conditions in southern Australia (in particular, declining soil moisture and increasing soil temperature) caused an onset of more rapid inactivation processes for the microorganisms in the present study (Figure 4). This, however, may not be the case in tropical crop-growing regions such as Queensland and, as such, these areas require further research to determine if there are similar or different decay patterns in different climatic regions. Based on the results of this study, the risk that enteric pathogens may persist on wheat plants and grains until consumed is considered to be low. Target microorganisms inoculated into the soil were at three- to four-log10 by springtime (Figure 4), and environmental strains of E. coli were approximately one-log10. Given that the decay times (T90) for the same microorganisms from the leaves and spikelets of a wheat plant were equivalent to one to three d (Table 1), these microorganisms would be below the detection limit within a matter of weeks. In addition, the changes in climate in typical spring to summer months are not favourable for the survival of enteric pathogens. Should any microorganisms survive in the field to harvest and be present on the grains, the time from harvest to consumption is usually more than four months due to transport, warehousing, shipping and storage. In this study maximum decay time T90 of 71 d was observed for bacteriophage MS2, which suggests that grain storage time of four months is a significant barrier in reducing the number of any surviving pathogens. Moreover, most foods produced from wheat involve some form
Technical Papers of processing such as grinding, milling, rolling, steaming and baking, therefore the risk of human enteric pathogens originating from land-applied biosolids and transmitting to humans at consumption (of cereal grains) is considered to be very low. In the dust study at harvesting time, highest numbers of microbial contaminants were found on the chaff in the field and, thus, the authors recommend that this region of the plant should be tested first for any potential contaminants that could become airborne in wheat dust. Overall, since the process of threshing was found to reduce enteric microorganism numbers, the risks of unsafe levels of bio-aerosols in the dust at harvest was considered to be low. From the results of this research work, it was reasoned that pathogens from biosolids are of greatest risk to humans immediately following dispatch from the wastewater treatment plant. As microbial contamination levels are highest during this time, transport providers, handlers, spreaders, farmers and farm workers are at greatest risk of exposure to pathogens (Figure 1). After the biosolids have been incorporated with the soil, the pathways to ingestion are low where withholding periods are maintained. Therefore, the main pathway to transmission may be more prevalent from poor hygienic practices such as food consumption following handling, or the transfer of biosolids into vehicles or homes.
In addition, it was found that decay times were specific to microorganism type. Microorganism decay was correlated to the changes in soil moisture and soil temperature in the field. Results of this study also suggest that there is very limited potential for enteric pathogens survival on wheat phyllosphere and grains. Overall, the risk of transmission of disease-causing microorganisms (pathogens) from landapplied biosolids in a wheat crop was considered to be low where withholding periods are maintained.
The Authors wish to acknowledge the Water Corporation of Western Australia, CSIRO Water for a Healthy Country Flagship Program, Water Quality Research Australia (WQRA) and the Victorian Department for Human Services for project funding.
THE AUTHORS Dr Karen Schwarz (email: email@example.com) recently completed her PhD on the fate of human enteric pathogens following the land application of biosolids in agriculture. Dr Simon Toze (email: simon. firstname.lastname@example.org) is a Research Team Leader with CSIRO Land and Water Division and the Water for a Healthy Country Flagship in Brisbane, and an honorary Associate Professor with the UQ School of Population Health. Dr Deborah Pritchard (email: d.pritchard@curtin. edu.au) is a Senior Lecturer at Curtin University in Perth and was awarded the 2012 AWA Water Industry Woman of the Year. Dr Jatinder Sidhu (email: email@example.com) is a Research Scientist in the Urban and Industrial Water research theme of CSIRO Land and Water, Brisbane. He is an Environmental Microbiologist with 10 years of experience in public health-related Water Microbiology. Dr Yutao Li (email: yutao. firstname.lastname@example.org) is a Senior Research Scientist at CSIRO Animal, Food and Health Sciences, Brisbane, with expertise in the statistical analysis of quantitative, molecular and population genetics data.
Biosolids? Honours thesis, Muresk Institute. Northam, WA. Curtin University of Technology. DEC (2012): Western Australian Guidelines for Biosolids Management: Department of Environmental and Conservation, Perth, WA. Epstein E (1998): Pathogenic Health Aspects of Land Application. BioCycle, September 1998, pp 62–66. Epstein E (2003): Land Application of Sewage Sludge and Biosolids. Boca Raton, Florida. Lewis Publishers. Gerba C & Smith J (2005): Sources of Pathogenic Microorganisms and Their Fate During Land Application of Wastes. Journal of Environmental Quality, 34, pp 42–48. Horan N, Fletcher L, Betmal S, Wilks S & Keevil C (2004): Die-off of Enteric Bacterial Pathogens During Mesophilic Anaerobic Digestion. Water Research, 38, pp 1113–1120. Horswell J, Hewitt J, Prosser J, van Schaik A, Croucher D, Macdonald C, Burford P, Susarla P, Bickers P & Speir T (2010): Mobility and Survival of Salmonella typhimurium and Human Adenovirus from Spiked Sewage Sludge Applied to Soil Columns. Journal of Applied Microbiology, 108, pp 104–114. Joshua W, Michalk D, Curtis I, Salt M & Osborne G (1998): The Potential for Contamination of Soil and Surface Waters from Sewage Sludge (Biosolids) in a Sheep Grazing Study, Australia. Geoderma, 84, 1, pp 135–156. LeBlanc R, Matthews P & Richard R (2008): Global Atlas of Excreta, Wastewater Sludge and Biosolids Management: Moving Forward the Sustainable and Welcome Uses of a Global Resource. Nairobi 00100, Kenya: United Nations Human Settlements Programme (UN-HABITAT) and Greater Moncton Sewage Commission. Nicholson F, Groves S & Chambers B (2005): Pathogen Survival During Livestock Manure Storage and Following Land Application. Bioresource Technology, 96, pp 135–143. Schwarz K, Sidhu J, Pritchard D, Li Y & Toze S (2013): Decay of Salmonella enterica, Escherichia coli and Bacteriophage on the Phyllosphere and Stored Grains of Wheat (Triticum aestivum). Letters in Applied Microbiology. [doi:10.1111/lam.12149]. Schwarz K, Sidhu J, Pritchard D, Li Y & Toze S (2010): Decay of Escherichia coli in Biosolids Applied to Agricultural Soil. Proceedings of AWA Biosolids Specialty V conference, 2–4 June 2010, Sydney, Australia.
Chandler D & Craven J (1980): Relationship of Soil Moisture to Survival of Escherichia coli and Salmonella typhimurium in soils. Australian Journal of Agricultural Research, 31, pp 547–555.
Sidhu JP, Hanna J & Toze S (2008): Survival of Enteric Microorganisms on Grass Surfaces Irrigated with Treated Effluent. Journal of Water and Health, 6, pp 255–262.
Chaney R, Ryan J & O’Connor G (1996): Organic Contaminants in Municipal Biosolids: Risk Assessment, Quantitative Pathways Analysis, and Current Research Priorities. The Science of the Total Environment, 185, pp 187–216.
Sidhu JP & Toze S (2009): Human Pathogens and Their Indicators in Biosolids: A Literature Review. Environmental International, 35, pp 187–201.
Crute K (2004): Are Pathogens Present in Wheat at Harvest Following the Land Application of
Sorber CA & Moore B (1987): Survival and Transport of Pathogens in Sludge-Amended Soil: A Critical Literature Review. Cincinnati, Ohio: United States Environmental Protection Agency.
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BIOSOLIDS & SOURCE MANAGEMENT
This study provides data that can be used in management systems designed to reduce the transmission of human pathogens that may originate from biosolids reuse in agriculture. The key outcomes of this research were that enteric microorganisms are highest in numbers following application of biosolids, and that the enteric microorganisms decayed faster in soils amended with biosolids compared with unamended soil.
CONSTRUCTION AND COMMISSIONING OF HIGH AIR FLOW CAPACITY WET CHEMICAL SCRUBBERS Experiences and lessons learnt from the upgrade of the Odour Control Facility at Malabar Wastewater Treatment Plant J Kiesewetter, P Neall, G Stirling, J Cesca, H Ismail, L Haralambev
This paper discusses the experiences and lessons learnt from the construction and commissioning of the refurbished and upgraded Odour Control Facility (OCF) at Malabar Wastewater Treatment Plant (WWTP). The OCF consists of six wet chemical scrubber units operated in parallel and has the highest air flow capacity of any odour control facility in the southern hemisphere, treating a total foul air flow of 180 cubic metres per second (180 m3/s or 648,000 m3/h) across four duty and two standby scrubber units under normal operation.
Malabar Wastewater Treatment Plant (WWTP) has the largest hydraulic capacity of any treatment plant in New South Wales, Australia, treating an Average Dry Weather Flow (ADWF) of 465 megalitres per day (ML/d) of mixed domestic and industrial wastewater through a high rate primary treatment process. The liquid stream processes are located below ground, with odorous ventilation air being extracted through a network of fans and ducts and feeding a central plenum from which the OCF foul air fans draw air to feed the wet chemical scrubbers. Foul air is also extracted from the South West Suburbs Ocean Outfall Sewers (SWSOOS 1 & 2) and the Coogee sewerage system. Treatment of all foul air takes place through the OCF prior to atmospheric discharge through a manifold and a single discharge stack.
As part of the commissioning process, several key areas for improvement were identified and implemented; these included the optimisation of chemical dosing through feed forward control and the determination of the system air flow without the use of a traditional flow meter. In addition, the process performance was measured through online monitoring of the feed and discharge air hydrogen sulphide (H2S) and discharge air chlorine (Cl2) concentration; spot measurements of odour concentration through dynamic olfactometry; and gas constituents through gas chromatography–mass spectrometry. Preliminary testing of the upgraded OCF shows it has demonstrated compliance with strict performance requirements of less than 1,000 odour units (OU) and less than 50 parts per billion (ppb) of hydrogen sulphide in the exhaust gas stream. The preliminary stages of the OCF upgrade have been met with positive feedback from the Sydney Water plant operations team due to improved process performance, reliability and ease of operation. Keywords: Chemical scrubber, hydrogen sulfide, odour, sodium hypochlorite, sodium hydroxide.
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The Odour Management Program Alliance (OMPA), consisting of CH2M HILL, Abigroup and Sydney Water, has recently replaced and upgraded the wet chemical scrubbers at Malabar WWTP to reduce the risk of odours impacting the surrounding community. The obsolete scrubbers had been operating since 1989 and were at the end of their usable life. The upgraded OCF consists of six vertical, counter-current, packed tower chemical scrubbers, each with a design capacity of 45 m3/s at a design inlet Hydrogen Sulphide (H2S) concentration of up to 50 parts per million (ppmv). The single stage scrubbers discharge to a manifold, with the combined flow passing through a single stack, discharging 22.7 m above the base of the scrubbers. The upgrade included replacing the six obsolete scrubber towers, extraction fans and recirculation pumps; installing a new discharge manifold and stack supported by structural steel; upgrading
the chemical dosing and storage system; and associated mechanical, electrical and control system improvements. A staged construction approach was adopted, with the obsolete scrubbers being replaced in pairs, thereby leaving four scrubbers online for continuous gas treatment at any time. This construction methodology required the project to take place across three stages, each incorporating the upgrade of two scrubber units and associated chemical dosing equipment and ancillaries. To date, all six scrubbers have been commissioned and handed over to Sydney Water, and the six-scrubber ensemble is currently operating as part of a 42-day performance and process proving period. During the preliminary phases of the project, several improvements were realised and implemented to improve the operability and robustness of the OCF. These included: • A calculated air flow algorithm in the control system to estimate the air flow through each scrubber vessel; and • Feed forward control on sodium hypochlorite (NaOCl) dosing to each scrubber to improve performance at high hydrogen sulphide loading and highly variable inlet conditions. In addition, the following results have been noted from analysis of the upgraded OCF operation: • Reduced chemical consumption as compared to the expected values from stoichiometry; and • High performance of the upgraded OCF for discharge odour concentration, low (< 0.1 ppmv) chlorine (Cl2) emissions and nonmeasurable (<50 ppbv) hydrogen sulphide concentrations.
Table 1. Malabar OCF design parameters. Parameter
Liquid to Gas Ratio (L/G)
Number of Mass Transfer Units (NTU – H2S)
Conductivity Operating Range (min – max)
Recirculation Flow Rate
Superficial Gas Velocity
Empty Bed Residence Time (EBRT)
Sodium Hydroxide Dosing From Sodium Hydroxide Storage
Treated Air to Manifold / Stack Mist Eliminator
Sodium Hypochlorite Dosing From Sodium Hypochlorite Storage
Bleed Liquid to Head of Works
Scrubber Liquid Monitoring
Foul Air from Plenum
Foul Air Feed
A process flow diagram of an individual scrubber unit is shown Figure 1. Sump
Figure 1. Process flow diagram for the scrubbers.
The upgraded OCF is designed around the use of six vertical, singlestage, fibreglass reinforced plastic (FRP), counter-current packed towers, each five metres in diameter and 10.5 metres high. The towers are packed with three metres of Lantec® 4 inch Q-Pac material for mass transfer and mixing between the air and liquid phases. Each tower is located above its own 30 m3 lined concrete sump, with a variable speed drive vertical shaft cantilever pump installed to recirculate scrubbing solution from the sump to the scrubber liquid distribution system.
The inlet and outlet ducts to each scrubber can be isolated using pneumatically actuated dampers. Each scrubber discharges to a common FRP manifold which combines the discharge air and directs it to a single FRP stack, from which the hydrogen sulphide and chlorine concentrations are continuously measured using two Honeywell® Chemcassettes and two Honeywell® XCD instruments, respectively. The scrubber inlet hydrogen sulphide concentration is measured using two Honeywell® XCD instruments, which draw sample air from the centre of the foul air feed inlet plenum. The Honeywell® XCD is an electrochemical cell while the Chemcassette uses chemically impregnated tape and an optical device to detect changes in the colour of the tape as it reacts with hydrogen sulphide. The discharge hydrogen sulphide Chemcassette units
The OCF is operated using the setpoints shown in Table 2. The sodium hypochlorite dosing rate is set using PID control to target an ORP setpoint. To avoid ORP undershoot, overshoot, and sodium hypochlorite overdosing, which can often occur in wet scrubbing systems, feed forward control has been implemented at Malabar OCF. Feed forward control sets the minimum dosing pump speed setpoint to provide a constant minimum flow of sodium hypochlorite to each scrubber. Feed forward is active above an inlet hydrogen sulphide concentration of 2 ppmv and provides a moving baseline flow of sodium hypochlorite linearly proportional to the inlet hydrogen sulphide concentration (i.e. as the inlet hydrogen sulphide load increases, so does the sodium hypochlorite dose rate). The normal saw-tooth type dosing operation is also observed under feed forward control; however, the frequency of slug dosing is reduced and the peaks and troughs in ORP value are attenuated.
Table 2. Malabar OCF operating setpoints. Parameter
Conductivity operating range (min – max) Recirculation flow rate
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The sump liquid level is measured using a bubbler tube type level transmitter which, in turn, controls the addition of top-up water to maintain a constant liquid level. Air feed to each scrubber tower is via a 185 kW variable speed drive centrifugal fan. Differential temperature across each fan is measured using resistance thermometer detectors with data transferred to a Foxboro® Distributed Control System (DCS). The OCF key design parameters are shown in Table 1.
The liquid stream on each scrubber has online monitoring for recirculation flow, pH, oxidation-reduction potential (ORP) and electrical conductivity (EC). Feedback from the pH and ORP probes is input to a PID loop within the DCS with the output determining the dose rate of sodium hydroxide (NaOH) and sodium hypochlorite. Feedback from the conductivity transmitter is used to control the bleed rate, with bleed liquid being pumped from the discharge of the recirculation pump. Chemical dosing takes place using duty-standby diaphragm dosing pumps for each scrubber. Each dosing skid contains an electromagnetic flow meter, which is used to measure chemical consumption and dose rate.
Industrial Water Supply
METHODS AND MATERIALS
are ranged from 50 to 1500 ppbv, the inlet hydrogen sulphide XCD units are ranged from 0 to 100 ppmv, and the discharge chlorine XCD units are ranged from 0 to 15 ppmv.
Technical Papers AIR FLOW MEASUREMENT
The design of the upgraded OCF does not allow for a traditional flow meter to be used for air flow measurement. Foul air from the underground treatment plant passes through a series of ducts which combine and pass to a central underground plenum, about 40 metres in length, seven metres in width and nine metres high. Foul air is drawn directly from the plenum via the foul air fans, which discharge through a short section of duct and a damper to the scrubber inlet. Each scrubber then discharges through a two-metre circular damper to a manifold, which directs all flow through a single discharge stack at a velocity of 20m/s. Throughout the entire arrangement, there are no locations with an adequate length of straight ducting to give uniform air flow, so accurate flow measurement is not possible. The OCF is designed to extract and treat 180 m3/s of foul air from the underground treatment plant to meet ventilation requirements and to prevent fugitive emissions of odorous air; therefore, being able to estimate the treated air flow is of great importance to plant operators. To overcome the lack of a traditional flow meter, an alternative method for flow estimation has been implemented. When a fan is used to move air, it adds energy to the air in the form of a pressure, temperature and velocity change. The
energy is added through electrical energy, which is then converted to mechanical energy through the motor and fan assembly. This increase in pressure and air temperature can be measured and is dependent on the air constituents (specific heat capacity), mechanical energy supplied to the air (electrical power from variable speed drive and motor efficiency), and the efficiency of the fan assembly. By measuring the temperature rise across the fan and the fan motor electrical power consumption (as measured on the variable speed drive), these values can be entered in the sensible heat equation to give an estimate of the air flow. A similar approach has been used previously for high accuracy estimation of pump efficiency and flow with promising results. Also, by comparison of the ideal, isentropic temperature rise expected across the fan and the actual temperature rise measured in the field, the device’s mechanical efficiency can be calculated. The method described here accounts for the fan impeller mechanical efficiency, as reduced fan mechanical efficiency will result in a temperature rise above the isentropic value and, hence, a reduction in calculated air flow. SCRUBBER SYSTEM PERFORMANCE
The odour concentration in the scrubber inlet foul air and in the processed air from scrubbers 5 and 6, and composite samples from the discharge of scrubbers 3, 4, 5
and 6 at the Malabar OCF were measured by taking bag samples, which were then analysed using dynamic olfactometry. The samples were collected and analysed under the Australian and New Zealand Standard AS/NZS method 4323.3.2001, which is the equivalent of the European EN13725 standard. Following odour sample collection, each of the sample bags was analysed for hydrogen sulphide concentration using a calibrated gold film Jerome® 631-X analyser. Gas Chromatography–Mass Spectrometry (GC-MS) analysis for sulfur gases with sulfur chemiluminescence detection were carried out to a method complying with NIOSH standard using a Varian-Air GC-MS. Measurement of VOCs was carried out to US EPA Method TO-15.
RESULTS AND DISCUSSION AIR FLOW MEASUREMENT
The differential temperature method has been employed at the OCF for air flow estimation, with calculated air flow results showing good correlation with factory acceptance testing (FAT). The scrubber 3 fan FAT curve is shown in Figure 2 with the curve scaled to match operating conditions on site (operating speed of 80% or 40 Hz). At this speed, the fan differential pressure as measured using a Magnehelic® gauge is constant at 1.2 kilopascals (kPa). The differential pressure gauge tapping points at the inlet plenum offtake and fan discharge are about equal in cross-sectional area, and so the effect of dynamic pressure can be ignored, thus the differential pressure can be considered equal to the fan static pressure. Taking the above into account, the scrubber 3 fan operating point is shown plotted in Figure 2, giving an air flow of 43m3/s at 1.2 kPa static pressure. For comparison, the differential temperature method for air flow estimation is described in Table 3 using actual plant operating data.
The sensible heat rise equation is shown below:
Rearranging to make air flow (Q) the subject gives:
Figure 2. Scrubber 3 fan FAT curve scaled to 40 Hz showing operating point.
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Substituting the values from Table 3 gives a calculated air flow of 41.2m3/s.
Table 3. Scrubber 3 inputs for differential temperature air flow method. Measurement
Fan inlet temperature
Fan discharge temperature
Estimated foul air relative humidity from water balance across scrubber
Foul air density at fan inlet conditions
Foul air specific heat capacity
Electrical power supplied to fan motor from variable speed drive
Motor efficiency from Type Test Certificate
Motor mechanical power
Table 4. Summary of chemical consumption data for November/December 2012. Mass of H2S treated (kg/d)
Vol of NaOH dosed at 27% (L/d)
Vol of NaOCl dosed at 12.5% (L/d)
Molar ratio – NaOH:H2S
Molar ratio – NaOCl:H2S
Estimation using the differential temperature rise method gives an air flow 4.2 % less than the value estimated from FAT, which was undertaken under near ideal test conditions using a pitot tube transversal as per AS2936-1987, well within the range of instrument error. ACTUAL VERSUS THEORETICAL CHEMICAL CONSUMPTION
Wet chemical scrubbers of the type employed at Malabar OCF use a scrubbing solution consisting of water, sodium hydroxide and sodium hypochlorite for absorption and oxidation of hydrogen sulphide and other reduced sulphur compounds. In general terms, the sodium hydroxide is used to increase the liquid pH and, therefore, to promote absorption of hydrogen sulphide to its dissolved, ionic state of HS- or S2-. The role of sodium hypochlorite is to promote oxidation of the dissolved sulphide ions to form more stable sulphate ions. The overall reaction is shown in the equation below.
To compare actual plant operating data with the theoretical chemical consumptions derived from stoichiometry, the sodium hydroxide and sodium hypochlorite consumption for the four operating scrubbers at Malabar OCF was monitored over a two-month period during November and December 2012. During this time, the daily mass of hydrogen sulphide was also calculated using the inlet hydrogen sulphide concentration and the total treated air flow as estimated using the differential temperature air flow method. This data was analysed to determine the actual molar ratios observed between sodium hydroxide, sodium hypochlorite and hydrogen sulphide. Data was collected for chemical consumption and hydrogen sulphide mass loading on a daily basis for the period from 1 November to 31 December 2012, when four of the upgraded scrubber were operating. Sodium hydroxide is dosed
Plotting the molar ratio of sodium hydroxide and sodium hypochlorite against the mass loading of hydrogen sulphide shows a correlation, with increased loadings resulting in an apparent decrease in relative chemical consumption for both sodium hydroxide and sodium hypochlorite (Figure 3). The data set in Table 4 shows that under most operating conditions seen at Malabar OCF, the consumption of both sodium hydroxide and sodium hypochlorite is substantially below the predicted quantities from stoichiometric estimates. Also of note is the increase in apparent relative chemical consumption at reduced hydrogen sulphide loadings of about 45 kilograms of hydrogen sulphide per day (kg H2S/d) or a daily average of 2 ppmv. It can be hypothesised that the increase in relative chemical consumption at low loadings may arise for the following reasons: • Lower driving force at low concentrations, reducing the efficiency of the reactions; • Side reactions between sodium hydroxide, sodium hypochlorite and other components in the foul air/water having a relatively larger impact on total chemical consumption; • A relatively higher loss of sodium hypochlorite due to transfer to gas phase as compared to the quantity consumed through reaction with dissolved sulphide; • Increase in the impact of bleed loss/dilution water addition on chemical dilution and loss; and • Less efficient absorption and oxidation of hydrogen sulphide at lower concentrations. At increased loadings, these factors would be less noticeable, as the majority of added chemical would be consumed in the absorption and oxidation of incoming hydrogen sulphide. It can be hypothesised that the lower relative chemical consumption at higher loadings may arise for the following reasons: • Loss of sulphide in the bleed stream;
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Other significant side reactions can also play a role, such as partial oxidation of dissolved sulphide to form elemental sulfur, absorption of carbon dioxide from the foul air stream (common at high pH levels) and precipitation of carbonates from the water supply (generally only a problem when dealing with a high
carbonate concentration water supply, which is not the case at Malabar OCF). Most wet chemical scrubber systems are designed using the stoichiometric values shown in the overall reaction balanced equation to calculate chemical consumption and dosing pump sizing. Following the molar ratios, this equates to 2.35kg of sodium hydroxide and 8.75kg of sodium hypochlorite consumed for every 1kg of hydrogen sulphide treated.
to the scrubbers at 27% concentration by weight and sodium hypochlorite is dosed at 12.5% concentration by weight. The totalised daily volumes of chemicals used were converted to molar quantities, as was the daily totalised hydrogen sulphide treated. A summary of the data set is shown in Table 4.
Figure 3. Molar ratio NaOH:H2S (left) and NAOCI:H2S (right) versus scrubber H2S loading. Table 5. Results of the odour and H2S measurements of Scrubbers No 5 and No 6. Date
Scrubber 5 outlet
Odour character rotten egg, raw sewage
fresh sewage, septic
Scrubber 6 outlet
fresh sewage, septic, sweet rotten egg, septic
Scrubber 5 outlet
fresh sewage, septic, sweet
Scrubber 6 outlet
fresh sewage, septic, sweet
rotten egg, septic
Scrubber 5 outlet
Scrubber 6 outlet
rotten egg, sewage
Scrubber 5 outlet
Scrubber 6 outlet
Table 6. Results of the GC-MS analyses of Scrubbers No 5 and No 6. Date
Sample location Common inlet
Scrubber 5 outlet
Scrubber 6 outlet
Scrubber 5 outlet
Scrubber 6 outlet
â€˘ Partial chemical oxidation of sulphide in the scrubber; and
H 2S ppmv
â€˘ Some natural buffering capacity of the water. SCRUBBER SYSTEM PERFORMANCE
The performance testing of the stage 1 upgrade scrubbers (scrubbers No. 5 and No. 6) was carried out over a 14-day period, namely, 25 June 2012 to 3 August 2012. This involved the collection of air
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samples over four separate days during this period. A summary of the results are shown in Table 5 and Table 6. These results clearly demonstrate that the scrubber performance exceeds the design requirements, with average outlet concentration of odour and hydrogen sulphide being 580 OU and <30 ppbv respectively, as measured using dynamic olfactometry and the Jerome analyser. Further sampling was undertaken
on 4 April 2013 to measure the odour concentration in the air leaving the common scrubber discharge stack. During this sampling event, scrubbers 3, 4, 5 and 6 were operating. Two samples were collected and analysed using dynamic olfactometry, giving results of 76 OU and 139 OU. These results indicate the OCF is exceeding performance requirements for discharge odour concentration, producing treated air with extremely low odour concentration.
Technical Papers CONCLUSIONS The construction and commissioning of the Malabar WWTP OCF has provided an upgraded facility capable of achieving ventilation requirements and foul air treatment to strict discharge constraints of less than 50 ppbv hydrogen sulphide, less than 0.1 ppmv chlorine, and less than 1000 OU. The temperature rise method for air flow estimation across a fan was trialled for estimation of air flow through fans without the use of a conventional flow meter. Results indicated close correlation with those seen using a traditional pitot tube traversal method. Further work is suggested in this area to confirm the correlation exists over a range of operating conditions. Examination of plant operational data has shown a substantial variance between chemical consumption expected from stoichiometry and that observed in the field. At low loadings of hydrogen sulphide (less than 2 ppmv daily average), the molar ratio of both sodium hydroxide and sodium hypochlorite were measured to be significantly above the stoichiometric estimate of four moles of sodium hypochlorite for each mole of hydrogen sulphide treated, and two moles of sodium hydroxide for each mole of hydrogen sulphide treated. Above a daily average hydrogen sulphide loading of approximately 2 ppmv, the stoichiometric ratios of both chemicals dropped substantially, approaching a 1:1 molar ratio. The increased molar ratios observed at low hydrogen sulphide loading is attributed to a relative increase in chemical lost to bleed, stripping of chlorine to the gas phase, and side reactions with foul air and water constituents.
ACKNOWLEDGEMENTS The Authors wish to acknowledge the great work of the construction and commissioning team at OMPA Malabar and the support and experience of the Sydney Water plant operations team. Special mention is also given to Bart Kraakman of CH2M HILL for his contribution and peer review of this paper.
Phillip Neall (email: Phillip. Neall@ch2m.com.au) is a Senior Project Manager with over 30 years of extensive experience in the water and wastewater industry, specialising in odour control, materials handling, pumping/piping systems, foul air collection and treatment and chemical dosing systems. Phillip’s role on the OMPA Malabar project was Process Mechanical Lead, with involvement from preparation of TOC estimates and mechanical specifications through to managing all site activities for mechanical contractors, including factory inspections and performance testing of fans and pumps, FRP vessels and ducting. Guy Stirling (email: Guy. Stirling@ch2m.com.au) is an Electrical Project Engineer with 15 years’ experience in chemical and biological odour removal, incineration and flares, 10 years in wastewater DAFF, BNR and water treatment, 14 years experience in food manufacturing projects and maintenance, and two years working with industrial robotics and maintenance. Guy has extensive experience in electrical control system design, MCC development, PLC, DCS and SCADA development and programming, as well as instrument and pneumatics specification and design. Josef Cesca (email: Josef. Cesca@ch2m.com.au) is a recognised national expert in air and odour emissions control and permitting for municipal and industrial applications and wastewater collection and treatment systems. He is currently the Technology Leader for Odour and Air Quality in the Asia Pacific Region for CH2M HILL, and has over 20 years of experience in odour control and measurement in wastewater collection systems and treatment facilities.
Hussein Ismail (email: Hussein.Ismail@lendlease. com) is a Senior Project Engineer with 11 years of experience in the wastewater industry. He has been involved in the construction and commissioning of numerous wastewater treatment plants either as an Operator, Commissioning Engineer, Commissioning Manager, Project Engineer, Senior Project Engineer and Project Manager. Hussein’s role with Abigroup Water on the Odour Management Program Alliance at Malabar WWTP was as Project Manager, where his responsibilities included the delivery of the Malabar construction project, involving contract management, construction and commissioning. Hussein was responsible for leading the team delivering the updated OCF, integration with the existing system and client service management. Lubomir Haralambev (email: Lubomir. Haralambev@sydneywater. com.au) holds a Bachelor of Science degree from the Higher Institute of Chemical Technology, Sofia, Bulgaria. He has been a Production Officer working for Sydney Water at the Malabar WWTP since 2007, with responsibilities ranging from daily operations support to project management. Lubomir was heavily involved in all aspects of the OMPA Malabar OCF upgrade, from the design phase through to handover. He has previous experience in Chemical Development and Quality Assurance and Quality Control across various companies in Australia and abroad.
REFERENCES Basu S, Gu ZC & Shilinsky KA (1998): Application of Packed Scrubbers for Air Emissions Control in Municipal Wastewater Treatment Plants. Environmental Progress, 17, 1, p 9–18. 1998. Green D & Perry R (2007): Perry’s Chemical Engineers’ Handbook, Eighth Edition. McGraw-Hill Education, 2007. Maddy P, Routley R, Baxter K, Chen P & Lourensz R (2005): Pump Efficiency Monitoring And Management At Melbourne Water, In 68th Annual Water Industry Engineers and Operators’ Conference 2005. Schweppes Centre, Bendigo. McPherson MJ (2009): Subsurface Ventilation and Environmental Engineering. Chapman & Hall.
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Jonathan Kiesewetter (email: Jonathan. Kiesewetter@ch2m.com.) is a Process Engineer specialising in wastewater treatment and odour mitigation for municipal applications. He has several years of experience in wastewater odour modelling,
development of mitigation strategies, and construction and commissioning of odour control technologies. He has worked on projects for several municipalities across Australia and has experience in odour sampling, developing odour inventories, dispersion modelling, and development of odour mitigation strategies. Following completion of the OMPA Malabar project, Jonathan has relocated to Manitoba, Canada, to continue work with CH2M HILL Canada.
water business DELIVERING INNOVATION IN FIELD-BASED INSPECTIONS
• Visual representation of assets via marked-up drawings/aerial photographs with links back to asset reports;
While manufacturing, construction and agriculture rank as some of the industries with the highest risk of accidents worldwide, no industry is an accident-free zone. Universal factors contributing to fatal incidents include falls through access covers, from walkways and platforms due to grid mesh and handrail failure, and into open manholes. In its Notifiable Fatalities Monthly Report for December 2012, Safe Work Australia reported a total of 198 notifiable fatalities in 2012, rising from 138 in 2010/11. Of these, 25 were the result of falls from a height, with a further 25 due to workers or pedestrians being hit by falling objects. These contributed to approximately 25% of fatalities nationally. Such incidents bring home the importance of recognising risk in the workplace and taking measures to prevent them occurring.
• Enhanced information gathering via smart data collection;
One of the ways Aurecon contributes to a safe working environment is by assisting clients with safety risk assessments of walkway and platform areas, access covers, grates, hatches, points of access and safety railings. Conscious of the need for greater efficiency in the collection of data and reporting, we turned to technology. The result is an innovative inhouse-developed mobile computing system for field-based engineering inspections and assessments, which has been successfully deployed for a number of water authorities in Victoria and South Australia. The Asset Inspection Tool provides clients with the knowledge to make informed maintenance decisions and contributes to the creation of a safe work environment. It works by providing standardised inspection forms at the front end of a purposedesigned database, which are completed in accordance with a reference document for consistency. The database utilises client-agreed risk matrices to assess the information entered, and its outputs are automated rectification recommendations and colour-coded work priorities. The tool generates automated detailed output reports with visuals of the asset and its defects, and summary reports prioritising the rectification works per assessed area. The building blocks of this asset inspection tool include Australian Standard
water November 2013
• Linkage to existing asset management systems; • Full connectivity enabling optimum performance of inspection team on-site; • Future re-inspection capability; Close up view of the mobile computing system for field-based asset inspections.
• Lower costs due to an increased efficiency in inspection times of around 40%;
AS 1657–1992 Fixed Platforms, Walkways, Stairways and Ladders and AS 3996 – Access Covers and Grates, which set out the design, construction and installation requirements for such assets intended to provide means of safe access to places normally used by workers. The developed tool directly references these Australian Standards, and applicable requirements are integrated into the standardised inspection forms.
• Facilitation of easy adoption by new users, eliminating waiting for the “A team” through the smarts in the tool.
Moreover, the driving force behind the tool is the client’s agreed risk matrices, which capture the client risk profile and specify the rectification requirement for each defect and the priority for rectification based on the perceived consequence. The front-end engineering and collaborative agreement with the client enables the programming of the assessment and rectification recommendations into the tool by senior engineers and subsequent undertaking of inspections by more junior team members. This innovative approach takes field-based engineering inspections to a new level through the combination of asset inspection processes with proven, sound engineering techniques. The integration of outputs directly into a database allows the sorting of data to identify trends and isolate types of assets, and enables the client to update the asset management system with appropriate data. It also enables comparison of future inspections of the same assets against earlier inspections. Apart from the positive contribution to safety, the use of the tool has demonstrated the following benefits to the water authorities involved: • Instant reporting incorporating photographs and GPS coordinates;
Case Studies Aurecon was engaged in 2011 to conduct a detailed inspection of all access covers, walkway gratings and accessible handrails at a wastewater treatment plant in Victoria. The project involved the inspection and assessment of 10,000 access covers and grates and 32 kilometres of handrails for compliance and condition. The inspection works for this project generated 3,233 reports accompanied by recommendations for remedial works. Using a tablet-based data collection method, the project team, working alongside plant operators and maintenance crew, was able to inspect and assess all assets and download outputs directly to the client’s asset management system and deliver a series of standard details for rectification works. This assignment was also extended to include other water and wastewater treatment facilities, pumping stations and valve complexes for the water authority. Aurecon was also engaged by SA Water in 2012 to create a similar tool for the purpose of inspecting a cross-section of gratings, handrails and access platforms across the Glenelg Wastewater Treatment Plant. The tool was successfully tailored to suit SA Water’s risk management profile and the rollout of the inspection program at the Glenelg Wastewater Treatment Plant was regarded as a success. SA Water now proposes to roll out the engineering inspection and assessment process using this tool across all access covers, walkways and handrails in its network.
water Business Some of the common issues encountered during the inspections of the access covers, handrails and access platforms at the various wastewater treatment plants include: • Insufficient fixings to supporting structure; • Insufficient end bearing/end support of grating panels; • Grating installed to incorrect orientation; • Significant damage/corrosion to access cover/supports.
Following the inspections and production of the condition assessment reports, the water authorities, in conjunction with Aurecon, were able to develop a prioritisation list and identify those critical assets that required immediate attention. This approach enabled the water authorities to focus their resources and efforts on a hierarchy of critical assets and implement the appropriate measures to proactively manage occupational health and safety across its major operating facilities.
CONCLuSION The development of the mobile computing system represents a ‘paradigm shift’ in the way Aurecon’s engineers conduct fieldbased site inspections. Juggling reams of paperwork and drawings during site inspections has been replaced by a smarter approach of delivering these traditional engineering services, by: • Capturing information in a systematic and efficient manner; • Offering a tailored solution to specific assets, taking into account surrounding environments, service conditions and levels of service;
• Enabling electronic storage of all siterecorded data to facilitate identification of trends and classification of assets according to condition, risk and priority. This approach is fast becoming ‘business-as-usual’ practice for field engineers due to its ability to streamline field inspections and minimise office-based tasks following the completion of field work. Opportunities exist to expand on the capability of the mobile computing system to cover the field inspections of the following asset groups, in addition to access covers, walkways and handrails: • Stairs and ladders; • Bridges; • Pumps, pipelines and related appurtenances; • Material defects; • Vertical transportation infrastructure; • Telecommunications infrastructure. For more information please contact Todd.Sheldon@aurecongroup.com or Joey.Loke@aurecongroup.com.
HYDROVAR, the modern variable speed pump drive is taking pumping to a new level of flexibility and efficiency. Call us to discuss your applications: Melbourne 03 9793 9999 Sydney 02 9671 3666 Brisbane 07 3200 6488 Email: email@example.com Web: www.brownbros.com.au DELIVERING PUMPING SOLUTIONS
November 2013 water
Water Business COE DRILLING WINS INDUSTRY RECOGNITION Coe Drilling Pty Ltd has recently been recognised by its peers and the resources industry for bringing two techniques to Australia for the first time. The innovations were used for the LNG industry in Gladstone Harbour and were integral due to the close proximity of the works to the environmentally sensitive area of the Great Barrier Reef Marine Park. Coe designed and constructed three HDD pipelines 2125m in length beneath the entrance to Gladstone Harbour and the Narrows to Curtis Island. The pipelines – two potable water pipelines and a sewer pressure main – are to facilitate the provision of utility services to meet demand growth associated with LNG facilities in the area. Coe realised that in order to successfully complete the works with minimal harm to the environment, they could not drill from one side. As such, they used intersect technology and gyroscopic steering tools to complete the job. Eamon Foley, Contracts Manager, said that using the technology protected the
environment from a potential FRAC-out. “The technology used two rigs where you drill from both sides to meet in the middle,” he said. “The gyroscopic steering tools ensured accuracy and negated the need for laying survey tracking cables on the seabed in a busy harbour environment.” Coe Drilling worked with sister company Mears Group Inc, which is based in the United States and had previously used these techniques on some of their North America projects. Coe was recognised by the Australasian Society of Trenchless Technology at their annual award ceremony held last week, winning Project of the Year, New Innovation and New Technology, Machine, Tool, Material, System or Technique.
NEW LABORATORY METER RELEASED Hanna Instruments has released edge™, a full featured laboratory meter with revolutionary design features not usually associated with instrumentation. The meter, which measures pH, conductivity and dissolved oxygen, is incredibly thin and lightweight, measuring only half-an-inch thick and weighing just 250g, and
All the right connections for the water industry. Whether it’s for drinking, irrigation or industry, Australia’s climate and reliance on water has produced some of the world’s most innovative suppliers of water products and services. Now there’s an online tool that brings all these suppliers together in one central location. ICN’s Water Directory is a pivotal connection point for project and procurement managers looking for the best water industry suppliers in our region. This comprehensive directory has a powerful search function that allows you to find suppliers with capabilities that exactly match your needs. Combine this with the experience and knowledge of ICN’s consultants and you can be sure you’ll never miss an opportunity to find the perfect partner. Start exploring Australia’s ICN Water Directory today at water.icn.org.au
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blends elements of portable meters and bench-top meters into a single, seamless design. This versatility allows customers to use edge™ as a bench-top meter, a portable meter, or even attach it to a wall to free up valuable bench space in a laboratory. In addition to its thin, lightweight design, edge™ features a large 5.5” LCD with a wide viewing angle, capacitive touch keypad, dual USB ports, cradle with swivel arm electrode holder and an included wall mount. edge™ works with Hanna’s digital smart electrodes. Almost as advanced as the meter
Water Business itself, these electrodes feature a built-in microchip that stores sensor type, ID and calibration information that is automatically retrieved by edge™ once the electrode is plugged in. Simply plug in the sensor you want and begin measuring. Change measurement parameter by changing sensor – it’s that simple. The electrodes have a 3.5mm connector so users don’t have to worry about alignment and pins bending or breaking.
500mm into furnace from the block and was blanked off with a welded steel end plate which was 300mm X 300mm X 6mm thick on the fire side. The model “T” LinkSeal modular seal system was installed in the annular space between the steel pipe and the penetration through the concrete. The tested Model “T” Link-Seal maintained integrity performance for 132 minutes without the formation of gaps or fissures.
edge™ can be purchased as a complete kit, with the sensor of your choice. Sensors for other measurements can be purchased separately. Please contact our office for further information on www.hannainst.com. au, email firstname.lastname@example.org, call (03) 9769 0666 or fax (03) 9769 0699.
Exova Warringtonfire has issued the two hours fire-rating certificate of the Model “T” Link-Seal on 3 September 2013.
MODEL “T” LINK-SEAL ACHIEVES TWO-HOUR FIRE-RATING Projex Group is proud to announce that the Model “T” Link-Seal series has just attained a two-hour fire rating according to the Australian Standard 1530.4 and 4072. The Model “T’ Link-Seal can seal pipe penetrations through concrete structures and provides protection against flames, smoke, noise, gases and water, even when exposed to extreme temperatures. The Model “T” Link-Seal is composed of a high-temperature silicone rubber block with specially designed carbon steel pressure plates and nut and bolt assemblies, and is mainly used when a fire rating is required in buildings, fuel and oil bunds, water tanks, etc. The tested assembly comprised a twometre long section of 275mm diameter steel pipe with 10mm thick wall penetrating through a core hole in a 200mm thick precast concrete block. The pipe penetrated
“This two-hour fireproof certification showcases the quality and the efficiency of the Model “T” Link-Seal. It adds great value to our Link-Seal product range,” says Jim Kornmehl, director of Projex Group. “All engineers and project managers can now confidently specify the Model “T” Link-Seal when it comes to seal pipe penetrations within scenarios of extreme temperatures.” For more information please call the Project Group Office on 02 8346 8000 or email email@example.com
WEIDMULLER RELEASES ITS FIRST M12-X TYPE CONNECTOR Electrical connectivity supplier, Weidmuller, has expanded its range of industrial Ethernet connectivity products with the release of its M12-X type connector.
resistant to soiling and moisture. The unit features a full 360º metal shield connection point to ensure it is suitably robust for use in harsh industrial environments. Created to deliver a long life and errorfree connectivity, the connector’s pins are made from CuZn with a gold-plated contact surface. This assists the M12-X type connector in effectively withstanding up to 100 mating cycles. With convenience top of mind, the M12-X type connector is also designed for quick and easy field assembly. The connector does not require any special tools for installation. Plus, it can be operated in a broad temperature range, from –25ºC to +85ºC. Highly versatile, the connector is available as a stand-alone unit or with a moulded CAT7 cable in various lengths. The moulded cable ensures higher resilience, sturdiness and strength. For more information call Weidmuller on free call 1800 739 988 or email info@ weidmuller.com.au
WATER INFRASTRUCTURE GROUP UPGRADES ROCHESTER WATER RECLAMATION PLANT
Weidmuller’s M12-X type connector supports data transmission volumes up to 10 Gbits/s and meets the requirements of the latest Profinet Installation Guidelines for Cabling and Assembly as well as the demands of Category 6A. Purpose-built to withstand high vibration, the M12-X type connector is ideal for use in the mining, rail, road and transportation industries. Offering outstanding performance and high reserves for signals, the connector is both fast and efficient. The M12-X type Cat. 6A connector features excellent electrical and mechanical characteristics which facilitate reliable and error-free data transmission in real-time. Rated to protection class IP65 and IP67, the M12-X type connector is particularly
The new M12-X type connector and moulded plug-in cable from Weidmuller.
Water Infrastructure Group has started work on an upgrade of Coliban Water’s Rochester Water Reclamation Plant. The $9 million upgrade to the latest ultrafiltration wastewater treatment technology will enable the site to deliver additional recycled water to irrigation customers in the area. Peter Everist, Water Infrastructure Group General Manager, said that the new Rochester plant will be a showcase for the water industry. “The new treatment plant is designed around Water Infrastructure Group’s Virtual Control Room to improve reliability and reduce operating costs,” he said. “We’re
Key safety and installation instruction on demand codesafe.com.au
November 2013 water
using the latest Pentair X-Flow Airlift filtration technology, which provides scope for our Virtual Control Room to automate many of the processes in the treatment plant. “A major advantage is that the filtration membranes do not need to be submersed in a bioreactor tank. This makes the membranes much easier to clean and maintain. We expect that this will not only reduce chemical costs, but will also reduce the overall lifecycle cost of the plant and make it simpler and more reliable to operate. We’ve also chosen the Pentair technology for the Rochester plant because of its scalability. We can easily increase the volume and quality of the recycled water in the future as required.” Neville Pearce, Coliban Water General Manager Service Delivery and Infrastructure, said the upgrades would enable the plant to produce up to 240 megalitres of recycled water a year. “At present our Rochester Water Reclamation Plant treats to Class C standard, which is stored on-site in lagoons for evaporation and some on-site irrigation. Currently irrigation scheme customers are supplied with around 1,200 megalitres of Class B recycled water from our water reclamation plant in Echuca. These treatment improvements will enable us to treat to a higher class of recycled water, delivering an additional 220-240 megalitres a year to these irrigation customers.” Water Infrastructure Group will operate the new plant and also build and operate a 10.2 kilometre pipeline to transport the recycled water to the Singers Road Reclaimed Water Storage for distribution to Campapse Irrigation Scheme customers. Works are expected to be completed by July 2014.
UV-LED TRANSMITTANCE MONITOR The new Aquionics PearlSense T254 is the world’s first transmittance monitor to use UV-LED technology. The monitor provides UV disinfection system manufacturers and operators with highly accurate UV transmittance (UVT) readings in all conditions over an extended lifetime, ensuring proper UV dosing and efficient operation.
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PearlSense T254 features a patentpending fixed position single lamp and sensor design with an automatic two-point reference check. The design provides more accuracy than products using conventional UV lamps and sensors. A UV-LED light source allows instant activation and highly efficient, mercury-free operation. The PearlSense T254 is capable of battery and solar-powered operation, and can be used in a variety of configurations including handheld operation, installed directly in a pipe or bracket-mounted in an open channel environment. The monitor can withstand unlimited cycling without lamp degradation. UVT is used to track changes in water quality, and can also be used to alert to the presence of organic compounds and other issues. UVT values are communicated to the control system of a UV reactor and used in calculating the most efficient treatment process. From large municipal water treatment facilities to small food and beverage applications, consistently accurate UVT values can save energy and ultimately provide superior water quality. The PearlSense is part of the new UV-LED Pearl product range from Aquionics. For more information about Aquionics and its family of products, visit the company’s website at www. aquionics.com or call 1800 925 0440.
SENSOR DRIVE SATELLITE LEVEL TRACKING The Bintech Sensor Drive Satellite unit provides a versatile, self-contained, reliable solution for remote tank level measurement. The Sensor Drive Satellite range offers many solutions for remote measurement and monitoring. The SDS 6100 range is based on high-end, highly reliable and accurate sensors coupled with a satellite
communication module. To reduce even further reliance on local infrastructure, a solar-powered version is available in addition to 24VDC and 240VAC. To transfer level measurement or switching alarms from remote location, the SDS range comes with a satellite transceiver, used to log data and reports via satellite and providing a reliable solution for long-distance links in remote locations. For shorter links, please refer to the radio product, SDR 6010/6020. The satellite host allows the user to retrieve data using a web browser. The satellite unit also provides at any time the GPS coordinates of the current location of the sensor. This functionality is a key asset for management of a fleet of tanks, e.g. mobile tanks used for fuel delivery. Various options are available for powering the remote Sensor Drives: 24VDC, 240VAC and a solar power supply. The solar power supply option provides a reliable solution for remote sites with no or unreliable power supply. The internal battery allows for up to three days of use with minimal solar charge. The Sensor Drive Satellite can be fitted with the classic, simple and reliable Magnetic Float Switch. This sensor is a contact level switch, offering up to four switching points with different switching actions to choose from. As an alternative, we offer the well-proven, state-of-the-art ultrasonic level transmitters from Pulsar. These level transmitters provide the full range of functions used in continuous level measurement. The satellite communication module establishes a permanent communication link with the level transmitter and provides almost real-time level measurement, level alarms and instant access to measurement history. For more details visit www.bintech.com.au
Advertisers Index Aquatec Maxcon 11 Barron BC Bintech 21 Brown Brothers 93 Codesafe 95 Comdain 5 Hach Pacific 19 Hydro Innovations 27 ICN – International Capability Network 94 James Cummings 62 Mears 47 Nov Mono 17
OneStone Consulting Pentair
Tenix 31 Transfield 15 Water Infrastructure Group
Xylem 7 Zetco IBC
WaterMarked Valves THE COMPLETE RANGE
To see Zetcoâ€™s comprehensive range of WaterMarked valves, contact us today for a free brochure or visit the website
zetco.com.au 1300 659 639 firstname.lastname@example.org
Delivering innovative valve solutions
Optimum performance, precise control, perfect corrosion protection AUMA manufacture actuators for valves ranging from just a few centimetres in diameter through to products for weir gates several metres high. Combined with AUMA’s modern control concepts, integration with high perfomance ﬁeldbus distributes control systems is straightforward. Easy retroﬁtting, absolute reliability within any type of plant and always at the forefront of innovation. ■
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BARRON GJM Pty. Ltd. • P.O. Box 792 • Artarmon NSW 1570 • Tel. +61 294361088 • email@example.com • www.barron.com.au
Published on Nov 5, 2013
Published on Nov 5, 2013
This issue looks at "WaterAUSTRALIA: What Does The Future Hold", plus you’ll find a range of articles and technical papers on topics such as...