Water Journal September 2008

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Volume 35 No 6

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SEPTEMBER 2008

AWA JOURNAL OF THE AUSTRALIAN WATER ASSOCIATION

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Journal of the A,st,allan Wate, Association ISSN 0310-0367

Volume 35 No 6 September 2008

contents REGULAR FEATURES From the AWA President

Managing Water Assets

From the AWA Chief Executive As Ye Sow...

D Barnes 4 T Mollenkopf 5

Letters to the Editor

6

Crosscurrent

10

Aquaphemera

R Knee 12

Industry News

20

Events Calendar

28

AWA News

30

CERES' Pervious Parking Project - see page 20

FEATURE ARTICLES Carbon Pollution Reduction Scheme 40 Andrew Speers provides an overview of the challenges posed to the water sector as details of the proposed Carbon Pollution Reduction Scheme begin to emerge CRC for Water Quality and Treatment - Achievements

42

After the recent end of the 13 year CRC for Water Quality and Treatment, Angela Gackle examines some of the cooperative research centre's achievements

Going Nano - Nanotechnology In Water Treatment John Poon and Rob Huehmer discuss the new technology paradigm

rAWA CONTACT DETAILS Australian Water Association ABN 78 096 035 773 Level 6, 655 Pacific Hwy, PO Box 222, St Leonards NSW 1590 Tel: +61 2 9436 0055 Fax: +61 2 9436 0155 Email: info@awa.asn.au Web: www.awa.asn.au

DISCLAIMER Australian Water Association assumes no responsibility for opinion or statements of facts expressed by contributors or advertisers.

COPYRIGHT AWA Water Journal is subject to copyright and may not be reproduced in any format without written permission of the AWA. To seek permission to reproduce Water Journal materials, send your request to media@awa.asn.au WATER JOURNAL MISSION STATEMENT

'To provide a journal that interests and informs on water matters, Australian and international, covering technological, environmental, economic and social aspects, and to provide a repository of useful refereed papers. ' PUBLISH DATES Water Journal is published eight times per year: February, March, May, June, August, September, November and December.

EDITORIAL BOARD Chair: Frank R Bishop; Dr Bruce Anderson, ENSR Australia; Dr Terry Anderson, Consultant SEWL; Greg Finlayson, GHD; Robert Ford, Central Highlands Water (rtd); Anthony Gibson, Ecowise; Dr Brian Labza, Vic Health; Professor Felicity Roddick, RMIT University; Mike Muntisov, GHD; David Power, BEGA Consultants; Dr Ashok Sharma, CSIRO; and Bob Swinton, Technical Editor.

AWA

EDITORIAL SUBMISSIONS Water Journal welcomes editorial submissions for technical and topical articles, news, opinion pieces, business

44 Nanotechnology In Water Treatment - see page 44

information and letters to the editor. Acceptance of editorial submissions is at the discretion of the editor and editorial board.

• Technical Papers and Features Bob Swinton, Technical Editor, Water Journal - bswinton@bigpond.net.au AND journal@awa.asn.au Papers 3,000-4,000 words and graphics; or topical articles of up to 2,000 words relating to all areas of the water cycle and water business.

Submissions are tabled at monthly editorial board meetings and where appropriate are assigned referees. Referee comments will be forwarded to the principle author for further action. Authors should be mindful that Water Journal is published in a 3 column 'magazine' format rather than the full-page format of Word documents. Graphics should be set up so that they will still be clearly legible when reduced to two-column size {about 12cm wide). Tables and figures need to be numbered with the appropriate reference in the text e.g. see Figure 1, not just placed in the text with a (see below) reference as they may end up anywhere on the page when typeset.

• Industry News, Opinion pieces and Media Releases Edie Nyers, Editor, Water Journal - journal@awa.asn.au • Water Business and Product News Brian Raul!, National Sales and Advertising Manager, Hallmark Editions - brian.rault@halledit.com.au

ADVERTISING Advertisements are included as an information service to readers and are reviewed before publication to ensure relevance to the water sector and objectives of the AWA. Brian Rault, National Sales and Advertising Manager, Hallmark Editions - brian.rault@halledit.com.au Tel: +61 3 8534 5014 AWA BOOKSHOP Copies of Water Journal, including back issues, are available from the AWA Bookshop for $12.50 plus postage and handling.

Email: bookshop@awa.asn.au PUBLISHER Hallmark Editions, PO Box 84, Hampton, Vic 3188 Tel: 61 3 8534 5000 Fax: 61 3 9530 8911 Email: hallmark.editions@halledit.com.au

Sydney's second largest STP is at North Head and treats the effluent of 1.2 million people. In 2005 Sydney Water engaged United Group Infrastructure Pty Ltd to design and construct a new biosolids management facility to treat approximately 36 dry tonnes of biosolids a day. The new sludge digestion process will reduce that to less than 19 dry tonnes each day. At present, approximately 11 dry tonnes are produced. This has greatly improved the quality of the biosolids and reduced truck movements. One hundred per cent of biosolids captured by Sydney Water are reused, mainly in horticulture. Photo courtesy of Sydney Water.

water SEPTEMBER 2008 1

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Journal of the ..,,tralian Water Association ISSN 0310-0367

Sludge Treatment Processes: Innovations - see page 60

TECHNICAL FEATURES( ~

Volume 35 No 6 September 2008

contents

Fly Breeding In Biosolid Cake - see page 75

INDICATES THE PAPER HAS BEEN REFEREED)

BIOSOLIDS

Biosolids IV, Adelaide, June 2008 Sludge Treatment Processes: Innovations Branding of biosolids can differentiate good operations from the rest Odour Emissions from Sludges: a Laboratory Investigation Unfortunately no surrogate for odour could be identified

Report by EA (Bob ) Swinton

50

T Evans

60

M Carsen, T Anderson

66

J Davis, J Reynolds, I Miller, S Katupitiya

70

I R Dadour, S CVoss, N Penney

75

G M Peters, H V Rowley

80

DR Marlow

84

T Britton, GCole, RStewart, D Wiskar

89

S Chopra, A Holmquist, B Murray

94

C Hanley, M P Taylor

98

[ii

Odours from Biosolids - the Relationship with Stability: Phase II Inconsistency between indicators for both aerobic and anaerobic products

[ii Fly Breeding In Biosolid Cake Fly breeding appears linked to ambient temperature and the NH4 content of biosolid cake Biosolids: an Environmental Life Cycle Assessment The relative environmental sustainability of various applications ASSET MANAGEMENT

[i] Sustainability-Based Asset Management in the Water Sector Integration of sustainability principles into asset management

[i] Remote Diagnosis of Leakage in Residential Households 2% of meters accounted for 24% of night-time consumption WASTEWATER TREATMENT

[ii MIEXÂŽ Technology Decolourises a Papermill recycle stream The first industrial application, at MUd scale

[i] Wetlands Minimise Algal Growth in a Horticultural Centre Optimising reed bed technology for denitrification WATER BUSINESS

New Products and Business Information

104

Advertisers' Index

116

2 SEPTEMBER 2008

water

letters to the editor Water, Electric Power, Emissions and Climate Change In the June edition of Water, AWA CEO Tom Mollenkopf stated that water and electricity are closely linked. He wrote, "Some of the largest areas where electricity is consumed is in pumping water and wastewater or in operation of water treatment and wastewater treatment plants".

He went on to remark that both the water and electrical sectors are making substantial advances in developing sustainable approaches and that the water industry, " ... has done remarkable work in developing and adopting new technology .... ", including utilising more efficient pumps.

The wat er industry's remarkable work mentioned by Tom seems to have one glaring omission in my opinion. The technology to reduce aerator grid power consumption by displacing conventional aerators used for mixing in wastewater treatment plants by solar powered mixers has been available for many years. Indeed, the Nhulunbuy Waste Stabilisation Ponds project powered by solar powered near-laminar flow mixers won the John Wellard Sustainability Award in July 2006. A Darwin based engineering firm brought together, "sunlight and innovative technology" to significantly improve the effectiveness and sustainability of waste treatment ponds for the township of Nhulunbuy.

Submitting Letters The AWA Water Journal Editorial Committee encourage your feedback on articles featured in the Water Journal, or on issues affecting the water sector.

Letters should be less than 400 words, and if referring to a specific article, provide the issue number, page and article title.

Please include your full contact details with letters, and email to journal@awa.asn.au or fax (02) 9436 0155.

Traditional mixing options were considered by the engineering firm , but rejected in favour of solar. Results were reported to be remarkable. Dissolved oxygen levels increased throughout the depth of the lagoons, problems with stratification, odour and blue-green algal blooms did not reoccur, effluent quality increased and sludge levels decreased.

In spite of the results achieved with this project, solar powered mixers appear to have been ignored by the Australian water industry, even though similar reductions in energy use and therefore greenhouse gas emissions are being achieved in wastewater treatment plants in North America in all climate zones. Many well documented case studies have been published that demonstrate the effectiveness of solar powered mixers in reducing energy requirements while improving plant performance. Furthermore, the same solar powered mixers being used in wastewater treatment plants can be used in fresh water reservoirs to enhance water ecology including prevention of algal blooms and increased DO levels.

Solar powered mixers have other beneficial features; capital outlays are lower, installation is fast, no additional infrastructure is required and maintenance costs are minimal.

Why then the reluctance of the Australian water industry to adopt this technology?

Asset management has been put forward as one reason. Are worki ng aerators to be displaced when they have years of life left in them? Operating and maintenance costs need to be balanced against replacement costs for sure, but if we believe there is a need to reduce the water industry's energy use and greenhouse gas emissions in both absolute and relative terms, perhaps the industry needs to bear these costs?

Wastewater treatment plant operators certainly ought to be pressuring their engineering consu ltants and providers to consider not only the energy cost savings that can be made by using solar powered mixers when upgrading treatment plants or building new ones, but also the savings in capital costs, installation, infrastructure and maintenance. Providers of conventional aerators won't like it, although some "pure" aeration will be required until new, more energy efficient technology replaces these as well.

Introduction of new technology results in winners and losers, but the real winners are those that can adapt to change. The water industry can't afford to indefinitely stay with old, energy hungry aerator WWTP mixing technology, but needs to adopt new sustainable solar technology when the opportunity arises.

Harvey Gough, MRACI CChem, novasys group pty ltd

6 SEPTEMBER 2008 water

regular features

letters to the editor Involvement in AWA Specialist Networks I am always reading the promotional material that arrives about the advantages one can get by being involved with the AWA and the AWA's desire to grow bigger and more relevant in the water industry. In my view, this is the face AWA wants to get across to all and it is one that has merit.

Such a perception is good for the businesses involved, good for individuals, good for currying favour with government/ major players, it raises t he Association's profile and makes the Associat ion financially viable. All sounds ideal for everyone involved.

However there is a side that rarely get addressed - and that is the professional responsibilities of all the players - major and minor - and the "public interest" aspects involved with most everything we do.

In the course of my career I have seen a number of instances where professional people are forced to bow to the views put forward by one individual/organisation. When confronted by such a situat ion our professionalism can fail us or is put to one side - unless the person(s) involved are prepared to resign or desire to look for a new job/new client.

I'll use the example of the Public Service. Public Servants usually will never contrad ict what a more senior person from the same organisation puts forward because they fear their careers in the long term wil l suffer by such an action. Thus even though they may be aware that an action is flawed or has ulterior motives, such information rarely comes to light. The

politicisation of our public services has ensured even greater control over anyone who dares to question a publically stated objective. Th is also happens in private industry; however such actions are usually not on the same scale that a government action can affect the community.

All members of AWA need t o be reminded that their responsibilities are not solely to make dollars, promote themselves, their organisations, powerful contacts or politically popular ideas.

I guess what I am trying to say is that people/organisations cannot always be pushing thei r own (or their employer's) barrow - there are t imes in everyone's lives when individuals must push the community barrow, regardless of the effect such actions may have on themselves or their employers. Until t his happens as a matter of course our desire to be seen as professionals whose views can be trusted wi ll never eventuate.

The AWA t hat I would like t o see is one that can and would support individual members and organisations that find themselves professionally compromised. Th e AWA is a powerful veh icle that could assist and break down the "cycle of fear" mentioned above. However the AWA is itself in conflict here because the major players have t he influence to prevent any public action by the Association.

A Specialist Group wi lling to discuss or d ebate such issues could, in my view, promote the wider discussion within our own association.

Yours faithfully, Rein Loo, F.I.E. Aust., Life AWA

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crosscurrent deliver up to 250 million litres of drinking water a day in the summer of 2009-10, and can be able to be scaled up to 500 million litres per day if needed.

The NSW Independent Pricing and Regulatory Tribunal (IPART) has invited public comment on the implications for the water and wastewater prices for Hunter Water following new initiatives such as the Tilleg ra Dam, new recycled water schemes and other major issues.

IPART has also given its Final Report on prices that Sydney Water can charge for water, sewerage and stormwater services for the 4 years commencing 1 July 2008. It also covered charges for recycled water services to Rouse Hill and charges for miscellaneous ancillary services that Sydney Water provides. www.ipart.nsw.gov.au

Water quality at beaches and lagoons on the NSW Northern Beaches is set to improve with a $70 million project to reduce wet weather sewage overflows. Sydney Water is proposing a 3.6-kilometre storage tunnel running deep beneath Sydney's Northern Beaches, as one of the ways of reducing wet weather sewage overflows.

Queensland South East Queenslanders under Level 6 water restrictions continued to eclipse Target 140.

With recent rainfall lifting dam levels to 40%, the Queensland Water Commission raised the water use target for residents to 170 litres per day (up from 140 litres). Business and industry must continue to use water efficiently in accordance with Water Efficiency Management Plans. http://www.qwc.qld.gov.au/

south Australia Special water sharing arrangements to secure the critical human needs of Adelaide and other towns reliant on the Murray River will remain in place throughout 2008/09. A joint statement from Prime Minister Kevin Rudd and the governments of New South Wales, Victoria, South Australia and the ACT warned that the water outlook across the southern Murray Darling Basin further deteriorated between March and June this year.

The Murray-Darling Basin Commission is examining whether a temporary weir is req uired below Wellington to protect the lakes. This would allow the barrages currently separating Lakes Alexandrina and Albert from the sea to be opened allowing the sea water to cover exposed soil beds which threaten to turn acidic.

has begun. The first of eight stages of the project wi ll expand on Willunga's treated waste wat er system for irrigating open spaces in the area. The public-private consortium project eventually is expected to save more than 3800 megalitres of water annually.

Construction is complete on a new $21.5 million, 3.5 km enclosed Torrens Pipeline, which replaces the old, open channel Hope Valley Aq ueduct. Being gravity assisted, it does not need a pump station or electricity.

Tasmania lrrigators in Tasmania's Coal River district will have access to additional water thanks to the $10.5 million South East Tasmania recycled water scheme. Stage One will connect the Rokeby sewage treatment plant to the existing Coal River

AQUAPHEMERA Another unfortunate publication from the National Water Commission Approaches to urban water pricing released 23 July 2008 - full of contradictory statements and proposed directions. They say they want urban water to be equitable, efficient and pricing to convey important signals to customers. But inclining block tariffs are not supported by the NWC as being inequitable and inefficient, despite the fact that they are intended to make essential water needs cheaper than discretionary water use. "New sources of water should be priced in congruence with drinking water and to reflect externalities and avoided or deferred cost s for supply augmentations" - so new water sources should be subsidised, but we should be efficient and eq uitable?

"Improved metering will facilitate better responses to pricing policies" - so all water users will be forced to pay extra for smart meters. Where is the evidence that this is effective?

"National reliability benchmark specifying frequency and severity of water restrictions" - this is three years out of date. The WSAA Framework for urban water resource planning provides a method for communities to decide what trade-offs they want for setting the level of service provided by the utility - cost versus the risk of restrictions. Different communities value water differently, one size doesn't fit all.

"Greater opportunity for private sector investment and more competition, wholesalers and retailers" - the private sector can't invest because the returns are too low with current prices. So the NWC want wholesalers providing subsidised source water and retailers operating with miniscule margins (like the energy retailers), to make the industry competitive?

Their suggestions that made sense were scarcity pricing but is it equitable?; and metering tenants - which many municipalities are already doing.

The NWC cou ld assist the water industry by undertaking comprehensive research into the direct and indirect impacts of these initiatives across the whole community, before advocating unsubstantiated theory.

- Ross Knee

The first stage of Onkaparinga Council's multi-million dollar water recycling and reuse strategy, 'Water Proofing the South'

12 SEPTEMBER 2008 water

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crosscurrent irrigation area. A 900 megalitre buffer dam at Back Tea Tree Road wil l enable storage of recycled water when demand for irrigation purposes is low.

Hyrdo Tasmania has agreed to supply additional water to Gunns Limited so it can offer irrigation to land owners along the proposed pulp mill water pipeline t o its controversial timber mill. The timber company had an agreement with Hydro for the supply of 26 gigalitres (GL) per year from Lake Trevallyn, which may be raised now to 40 GL should the project go ahead.

Victoria In one of the first decisions of its kind in Australia, the Victorian Civil and Administrative Tribunal refused the development of six coastal dwellings partly due to the threat of increasing storm severity and rising seas levels from climate change.

Melbourne City Council's Environment Committee endorsed 'Total Watermark - City as a Catchment', a new strategy providing a framework for Melbourne to become a water sensitive city by implementing best practice water conservation, reuse and recycling and management of stormwater run -off. More information is available at www.melbourne.vic.gov.au

t DGARD#ER DENVER

Vict oria's dental and water industries are working with the Brumby Government on a new campaign to help prevent mercury from entering Victoria's sewerage systems through the launching a new $1 million volu ntary program 'Dentists for Cleaner Water'.

Yarra Valley Water was the first water utility in Victoria to undertake and pass the 'Victorian Regulatory Audit for Drinking Water Risk Management Plan' - an initiative by the Department of Human Services.

Victoria University and CSIRO are undertaking a Smart Water project to assist industrial water users decide if recycled water is suitable for their applications. As part of this project, a literature review covering issues such as water quality, corrosion , health risks and public perceptions has been produced. Copies of the literature review can be downloaded from http://isi.vu.edu.au/sitebuilder/projects/knowledge/ asset/ti les/31 / g ui d ancefortheuseofrecyc ledwaterbyind ustry. pdf

Western Australia

Water Corporation has launched a new program called FOGMan to reduce wastewater system blockages among its 5,000 indust rial and commercial customers throughout WA. The Fats, Oil and Grease Management (FOGMan) program

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crosscurrent aims to reduce the number of blockages caused by build up of fats and greases and wastewat er overflows to t he environment.

Industry Alinta LGA Ltd has launched a new brand and is now tradi ng as Jemena Ltd. Jemena - an aboriginal word meaning t o hear, to listen and to think was chosen because it reflects how the company does business. Last year, Alinta Ltd. was sold t o a consortiu m of Singapore Power International, Babcock and Brown Power and Babcock and Brown Infrastructure.

Singapore Power International has renamed the assets and businesses it acquired to bring them under the Jemena brand.

Energy Recovery Inc. (ERi) has been awarded the contract for the Hamriyah (Phase 1) Power Station SWRO Desalination Plan using PX(R) energy recovery devices for the 91 MU day plant in Sharjah, United Arab Emirates.

The Great Artesian Basin Coordinating Committee has establi shed 2 PhD top-up scholarships to foster better understanding of the GAB, and invites applicants pursuing a PhD in the social sciences, economics, engineering or science who are interested in contributing to the management of an iconic water resource to apply. http://www.gabcc.org.au/public/contentNiewCategory. aspx?id=73

International Some UK companies changed the way they charge nondomestic customers for surface water drainage. They have moved from a system based on the premises' rateable value to one based on t he area of the site from which surface water drains into the public sewers.

A new study of more than 1000 Maryland streams in the US fou nd that as climate patterns change, urban sprawl can pollute water with more nitrate than previously thought. This concerns scientists who are struggling to clean up water, because global warm ing is expected to cause exactly the kind of weather extremes that could make the problem worse.

The European Commission rejected the notion that farmers should implement river basin management schemes in exchange for agricultural subsidies, despite increasing fears over water shortages and droughts. Agriculture is currently the highest consumer of water in the EU at 69% of the total.

The creation of tidal marshes on the mud-flat side of the Dutch Closure Dike (Afsluitdijk) will provide the Netherlands with a sea defense, a new nature area as well as recreation opportunities. Experts have been called to present plans for the Afsl uitdijk market consu ltation.

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crosscurrent Torrential floods devastated the Carpathians, with over 30 deaths reported in the Ukraine and 5 in Romania. Reports estimated approximately 20,000 evacuees, 40,000 houses flooded, 33,000 hectares of agricultural soil destructed, around 600 km of roads and hundreds of bridges seriously damaged.

By melting icy soil in one of its on-board laboratory instruments, NASA's Phoenix mission robot confirmed the presence of frozen water on Mars lurking below the Martian permafrost. Until now, evidence of ice in Mars' north pole region has been largely circumstantial.

Giant sheets of ice totalling almost eight square miles broke off an ice shelf in the Canadian Arctic and more could follow later this year, scientists said on Tuesday. It was the largest fracture of its kind since the nearby Ayles ice shelf - which measured 25 square miles - broke away in 2005.

People in the News ROBERT FREEMAN, chief executive of the South Australian Department of Water, Land and Biodiversity Conservation and deputy president of the Murray-Darling Basin Commission, was appointed to chief executive to the new independent MurrayDarling Basin Authority.

DR CHRIS COLBY joined Arup's process engineering team in Adelaide bringing diverse and practical skills and experience in desalination, water treatment and reclamation systems, sustainability and carbon footprinting, and in the design, testing and commercialisation of process technology and equipment.

WAYNE MIDDLETON has been appointed State Manager of MWH's Queensland Operation. Wayne welcomes PETER QUINN, MATTHEW DAWSON, DAVID BELL, SHANE O'BRIEN, STEVEN MOORE, GARTH BELLINGHAM and MEGAN MCCAHON-BRICE to his Leadership Team.

Wayne.middleton@mwhglobal.com

DARRELL WHITT, outgoing State Manager for MWH's Queensland Operation, moved into a nationally focussed role as Manager, Corporate Development.

Darrell.whitt@mwhglobal.com

MARC FABIG, managing director of Osmoflo was recognised

by Ernst & Young as a regional winner of a 2008 Entrepreneur of the Year award. He started Osmoflo in 1991.

EMILIO GABBRIELLI returned to Australia after 5 years with GWP in Sweden and has taken the role of Business Development Manager for Befesa Agua. emilio.gabbrielli@befesa.abengoa.com

ANDREW KABLE is now the Director of H2O Talent, specialising in recruitment for the water industry. H2O Talent was previously the consu ltancy, technology and operations division of Water Recruitment Solutions. Andrew is also the current President of the NSW Young Water Professionals. andrew@h2ota1ent.com

CHRIS ELLIOT has been appointed to the role of General Manager at DORIC. Mr Elliott is an engineer and manager with 32 years' experience in the water industry. His most recent role was Regional Business Manager, South West Region with the Water Corporation. celliot @doricgroup.com.au

MWH has made a number of recent design team leader appointments in the Melbourne Office, including DAVID COOK (formerly with United Utilities, UK), MICHAEL PROITSIS (formerly with Maunsell), NEIL GERHARD (formerly with SKM) and FRANK TREZISE (formerly with Halcrow) . Soyun Punyadasa has also been appointed as Business Development Manager for MWH in Melbourne.

DAVID MIDDLETON was been appointed Regional Business Group Manager for the CH2M HILL Water Business Group for Australia and New Zealand, commencing 1 September. david.middleton@ch2m.com.au

DAVID NAYLOR has been appointed to the role of General Manager at lzzat Consulting Engineers after significant growth.

Contact david@izzat.com.au

Congratulations to JENIFER SIMPSON, whose publication "From waste-d water to pure water" was selected by IWA's international jury as the Category Winner in the category 'Best Popular Presentation of Water Science', as part of the IWA Communications and Marketing. The final selection of the Overall Win ner among the category winners will take place in Vienna before the IWA World Water Congress. http://www.iwa2008vienna.org/i8/.

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industry news Australia's Biggest Recycled Water Project Powers On The Western Corridor Recycled Water Project in South East Queensland is now pumping purified recycled water to Swanbank Power Station and Tarong North Power Station, freeing up to 41 megalitres of water per day.

It's another milestone for the recycled water project and means that the two power stations no longer rely on South East Queensland 's drinking water supplies to generate electricity. Based on cu rrent usage, sufficient water for about 300,000 people w ill remain in the region's main reservoir, Wivenhoe Dam, rather than being pumped to the power stations to generate electricity.

three advanced water treatment plants, eight storage tanks and nine pumping stations, is being constructed by five Alliances - Bundamba, Eastern Pipeline, Western Pipeline, Luggage Point and Gibson Island - working across 45 sites between Luggage Point t o the east and Caboonbah towards the north-west of South East Queensland.

International recognition for the Western Corridor Recycled Water Project has been significant. The project has won global awards from a number of international bodies, including an Honour Award in the International Water Association's Project Innovation Awards.

Infrastructure to deliver purified recycled water through underground pipelines between Bundamba Advanced Wat er Treatment Plant near Ipswich and Tarong Power Station was completed ahead of schedule. The second power station came on line only nine months after the Western Corridor Recycled Water Project started pumping purified recycled water to Swanbank Power Station.

The Western Corridor Recycled Water Project, a water supply network consisting of more than 200 kilometres of large-diameter underground pipeline,

Spray of purified recycled water into Tarong storage lake.

Accolades for Jim Gill Leading the world in strategies to provide water security in the face of cl imate uncertainty is the one of the major contributions of Dr Jim Gill, w ho last month was named the International Water Association's Grand Award recipient.

literally saving Perth and other areas of Western Australia from running out of water. The strategy has provided an outstanding example of a water utility taking a long-term, all encompassing view of ensuring security of supply by incorporating a combination of demand management techniques, catchment management, water trading with irrigators and the introduction of climate independent water resources such as renewableenergy driven recycled and desalinated water.

Jim Gill, CEO of Western Australia's Water Corporation, was recognised by the International Wat er Association for his Jim Gill, CEO Water outstanding vision, leadership, and Corporation and recipient of the 2008 IWA Grand Award. knowledge in opening new fields in sustainable water management.

He was one of the first to recognise the emerging impacts of cl imate change on wat er resources in Australia, and t o implement world-leading strategies to address them. The development of the Water Corporation's 'Security through Diversity' approach under his guidance was the most comprehensive strategy to manage the impacts of climate change on water resources in the country;

The Austral ian Wat er Association submitted Dr Gill's nomination for the IWA Grand Award with the support of water associations from around the world including Canada, South Africa, Japan , Singapore and Switzerland. The Grand Award is the highest honour bestowed by the International Water Association and wi ll be formally made at the World Water Congress in Vienna.

22 SEPTEMBER 2008 water

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industry news Waterlinks Speeds Sanitation to Asia The U.S. Agency for International Development (USAID), IWA and Asian Development Bank (ADB) signed an agreement during World Water Week in Stockholm to establish WaterLinks, an Asiawide partnership that will help provide clean drinking water and sanitation throughout the region by coordinating, promoting and aligning efforts to create Water Operators Partnerships (WOPs).

WOPs have proven their value in many parts of the world by successfully pairing, or "twinning," water operators in search of solutions with other operators who have addressed similar challenges. These twinning arrangements have helped recipient water operators improve their efficiencies and capacities, resulting in more people gaining access to safe drinking water and sanitation.

The rationale behind the WOPs is that most of the capacity for improving water and sanitation services lies with the operators, 90 per cent of which are publicly managed.

One of the initial benefits Waterlinks will provide is the development and maintenance of a knowledge hub web portal on WOP initiatives and best practices. The site wi ll collects and disseminates WOP approaches, training, toolkits and other capacity building materials, and WOP-related scheduled events.

The Waterlinks signing ceremony on August 19 in Stockholm with Amy Leung, Director - East Asia Department, Asian Development Bank; Paul Reiter, Executive Director, International Water Association; Jacqueline E. Schafer, Assistant Administrator for the Bureau of Economic Growth, Agriculture and Trade, U.S. Agency for International Development.

Visit www.waterlinks.org for more information.

Sustainable Land Management Funds to Help Reef

New ABS 'Basin' Statistics Report The Australian Bureau of Statistics (ABS) publication Water and the Murray-Darling Basin - A Statistical Profile (2000-01 to 2005-06) presents a range of water, social, environmental and economic statistics relating to the Murray-Darling Basin, and has been welcomed by the Murray-Darling Basin Commission as the first publication to treat the basin as one discrete statistical area.

The publication covers basin statistics on: • climate • water availability • water consumption • agricultural production • gross value of irrigated agricultural production • population • employment • social characteristics; and • natural resource management.

The Great Barrier Reef and Queensland's Burdekin Dry Tropics rangelands are beneficiaries of a $2.6 million Caring for our Country 2008-09 regional investment funding package aimed at delivering improved land management practices on a regional-scale to reduce land degradation and soil erosion that currently spills more than 4.5 megatonnes of sediment into the Great Barrier Reef lagoon each year.

The Caring for our Country package funds a range of activities to build on sustainable land management practices and maintain or rebuild resilient ecosystems.

24 SEPTEMBER 2008 water

To look at a copy of the new publication go to www.abs.gov.au/ausstats/abs@.nsf/mf/4610. 0. 55. 007

industry news Water Quality Research Australia

Water Quality Research Australia was formally launched with over 70 guests partaking in supper and drinks in Adelaide on Thu rsday 7 Aug ust. The event was held following the WQRA Board and Members' meetings earlier in the day, to take advantage of the mustering of representatives of participating organisations.

Ken Matthews, Chairman and CEO of the National Water Commission and Professor Don Bursill, Chair of the Water Quality Advisory Committee (WQAC) for NH MRC and previous CEO of the CRC for Water Quality and Treatment were guest speakers, and WQRA Chairman Professor Michael R Moore and CEO Jodieann Dawe also gave short addresses.

Ken Matthews, Chairman and CEO of the National Water Commission.

Jodieann Dawe can be contacted on 08 8259 0236, jodieann.dawe@sawater.com.au, and Michael Moore on 07 3274 9001, moore.wqra@gmail.com.

26 SEPTEMBER 2008 water

r

s

V

assure Pipe to PE100 polyethylene pipe is ideal for infrastructure water supply. Its flexibility and strength makes it easy and cheap to install. Trenchless installation techniques reduce time on site and the costs associated with disruption to existing services and utilities. The fully welded joint system reduces the need for anchorage blocks and prevents leaks from developing over time. PE100's high tensile strength ensures it can easily withstand the water pressures required. PE100's corrosion resistance and slow crack growth resistance ensure long life. This provides substantial longterm savings by eliminating the need for costly repairs. PE100 will not lose carrying capacity due to internal encrustation and is unaffected by ground movement.

PE100 pipe being Installed into old pipe.

Standard:

Polyethylene Metric Pressure Pipe is manufactured in accordance with AS/ NZS4 130 "Polyethylene (PE) pipe for pressure applications", Furthermore PPl 's pipe has WaterMark Product Certification wh ich ent ails an independent audit of material selection, production and testing . It signifies an added commitment to qual ity and is required by all pl umbi ng and wat er authorities.

WaterMark branding is standard on blue or blue stripe pipe.

Material: Th e basic polyethylene (PE) material classifications used for pressure pipes are PE80 and PE1 00. The number classification refers to the strength of the material with PE100 bei ng stronger than PE80. Pipe made from PE100 can withstand a greater pressure than pipe with the same diameter and wall thickness made from PE80 material. PE100 was first introduced into larger diameters but it is now being adopted as the st andard material for all PPl's Metric Pressure Pipe. This change is inline with worldwide trend s and it ensures that our customers are able to take advantage of the latest developments in plastics.

Pipe Life: The 50-year stress regression data used for classifyi ng PE pipe material has incorrectly lead to the assumpt ion that PE pipe systems have a life expectancy of 50 years. In reality, such systems can reasonably be expected to last much longer than 50 years.

Systems that are manufactured and i nstalled correctly can be reasonably expected to last in excess of 100 years before requiring rehabilitation. However a firm prediction can not be made, as there are many unforseeable factors operating in each system.

Pressure Rating & SOR: The pressure rati ng (PN -expressed in bar) is quoted at a temperature of 20°C for the conveyance of water. It provides a base guide to the pipes performance but it needs t o be adjusted for other fluids and temperatures.

The Standard Dimension Ratio (SOR) is the nominal ratio of the pipe's outsid e diameter to its wall th ickness.

The term SOR is

13.6 PN 3.2

PN 4 PN 6.3

11

PN 6.3

PN 8

PN 10

PN 12.5

PN 16

PN 20

Water at 40°C

PN 8

PN10

PN 12.5

PN 16

PN20

PN 25

Compressed air at 40°

640kPa

Colour - stripes or jacket: PE pipe is normally black due to the carbon black added for UV stabi lity. In cases where colour is required to help identify the contents, then it can be added as stripes or a jacket. PPI uses 8 stripes on all diameters. Stripes usually provide adequate identification, but in small diameters in confined spaces, jacketing may be preferred.

PESO Blue

Water or compressed air

Grey

PE100 Blue

Water or compressed air

Red

Fire Services

White

Solabloc

Purple

Recycled/Reclaimed Water

PE100 Yellow

Gas

Orange

Electrical

Sewer

White

Communications

PPI is always prepared to hel p develop pipes to suit individual projects, so please contact our sales office to discuss your special requirements. Our extra capability includes other PE or PP materials, custom sizing, special colours, jackets & stripes.

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events calendar EVENTS CALENDAR This list is correct at time of printing. Please check the AWA online events calendar for up-to-date listings and booking information at

www.awa.asn.au/events Date

Event

Contact

Date

Event

Contact Jeremy Lucas 08 8207 1341

Wednesday 17 SeptemberFriday 19 September

2008 QLD Trade Waste Conference and Trade Show Surfers Paradise OLD Australia

Kathy Bourbon 07 3846 1564

Monday 20 October

SA Branch Committee Meeting North Adelaide SA Australia

Wednesday 17 September

YWP Seminar Serles Sydney NSW Australia

Tanya Webeck 02 9467 8408

Tuesday 21 October

TAS Branch Committee Meeting Hobart TAS Australia

Rachel-ann Martin 03 9235 1416

Wednesday 17 September

NSW Branch Committee Meeting Sydney NSW Australia

Tanya Webeck 02 9467 8408

Thursday 23 Friday 24 October

Australian Water Industry Essentials Brisbane OLD Australia

08 8236 5200

T uesday23 Wednesday 24 September

Engineers - Operators & Liqu id Trade Waste Summit Sydney Olympic Park NSW Australia

Tany a Webeck 02 9467 8408

Friday 24 October

Water Awards Adelaide SA Australia

Jim Morran 08 8259 0372

N'ZWWA's 50th Anniversary Conference & Expo Christchurch New Zealand

Len Clapham +64 9636 3636

Monday 27 Wednesday 29 October

Sanitation and Water Conference 2008 Melbourne VIC Australia

Dominic Keyser

Wednesday 24 Friday 26 September Wednesday 24 Thursday 25 September

Desalting Conference Perth WA Australia

Hayley Galbraith 02 9436 0055

Wednesday 29 October

YWP Seminar Series Sydney NSW Australia

Tanya Webeck 02 9467 8408

Wednesday 05 November

Qld Branch Committee Meeting South Brisbane OLD Australia

Kathy Bourbon 07 3846 1564

Thursday 25 Friday 26 September

Australian Water Industry Essentials Melbourne VIC Australia

08 8236 5200

Evening Seminar Melbourne VIC Australia

Rachel-ann Martin 03 9235 1416

Friday 26 September

West Australian Dinner for WaterAld Perth WA Austral ia

T uesday 11 November

Tuesday 30 September Wednesday 01 October

IWA MIiiennium Development Goals on Sanitation Amsterdam The Netherlands

Tuesday 11 Wednesday 12 November

Australian Water Industry Essentials Perth WA Australia

08 8236 5200

Victorian Regional Conference Cape Schanck VIC Australia

Rachel-ann Martin 03 9235 1416

Tuesday 30 September

Blue ¡ Green Algae (Cyanobacteria) and Their Management Hobart TAS Australia

Thursday 13 Friday 14 November

IWA Membrane Conference Amsterdam The Netherlands

YWP Fast-Tracking YPs To Management Melbourne VIC Australia

Victoria Leavold 03 9313 8402

Wednesday 1 Thursday 2 October

Thursday 13 November

Wednesday 01 October

Qld Branch Committee Meeting South Brisbane OLD Australia

Saturday 15 November

YWP - L ittle Creat ures Tour Perth WA Australia

Catherine Miller 0416 289 075

Thursday 2 Friday 3 October

IWA Conference on Industrial Water Treatm ent Systems Amsterda m The Netherlands

Tuesday 18 November

Evening Seminar Hobart TAS Australia

Rachel-ann Martin 03 9235 141 6

Wednesday 19 November

NSW Branc h Committee Meeting Sydney NSW Australia

Tanya Webeck 02 9467 8408

Tuesday 7 October

V IC Branch Committee Meeting Melbourne VIC Australia

Kathy Bourbon 07 38461564

IWA 3rd Odour and voes Co nference Barcelona Spain

2008 Regional Co nference Gold Coast OLD Australia

Wednesday 8 Friday 10 October

Friday 21 Sunday 23 November

Wednesday 8 October

Technical Meeting South Brisbane OLD Australia

Kathy Bourbon 07 3846 1564

Wednesday 26 Thursday 27 November

Pre-Treatment for Membrane Applicat ions Sydney NSW A ustralia

Hayley Galbraith 02 9436 0055

Sunday 12 Wednesday 15 October

Onsite & Decentralised Sewerage & Recycling Conference Benalla VI C Australia

Hayley Galbraith 02 9436 0055

Wednesday 26 November

2008 Hodgs on Awards North Adelaide SA Australia

Mike Burch 08 8259 0352

Tuesday 14 October

Regional Seminar - B ioso lids Drying Geelong VI C Australia

Rachel-ann Martin 03 9235 1416

Thursday 27 November

Stormwate r Conference Melbourne VIC Australia

Rachel-ann Martin 03 9235 1416

Wednesday 15 October

NSW Branch Committee Meeting Sydney NSW Australia

Tanya Webeck 02-9467 8408

Friday 28 November

Water Awa rds Presentation Evening UWP/WEMA Perth WA Australia

Catherine Miller 0416 289 075

Thursday 16 Friday 17 October

Regional Conference Port Macquarie NSW Australia

28 SEPTEMBER 2008 water

Ra chel-ann Martin 03 9235 1416

Kathy Bourbon 0738461564

Rachel-ann Martin 03 9235 1416

Tanya Webeck 02 9467 8408

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awa news Joint AWA/IWA Membership Benefits

IWA Publishing is a globally renowned leader in water, wastewater and environmental publications, and in addition to receiving IWA's flagship journal Water21, membersh ip includes a 25% reduction on books and some free and paid other journal titles such as: • Water, Science and Technology • Water, Science and Technology: Water Supply • Journal of Water Supply: Research & Technology - AQUA • Water Policy • Journal of Water and Health • Journal of Hydroinformatics • Hydrology Research So consider joint membership, and let the experience begin.

Contact AWA Member Services for further information +61 2 9436 0055.

The International Water Association (IWA) is a global network of water professionals, which spans the continu um between research and practice and covers all facets of the water cycle.

It is affiliated with the Australian Water Association (AWA) and incorporates 10,000 individuals, 400 corporate members and national committees in around 80 countries. By joining /WA, supplementary to your AWA membership, you will become part of a fellowship of like-minded water sector specialists operating at the heart of innovation - across the world!

IWA have a substantial membership base within Australia and across the Asia Pacific region (ASPIRE), and are represented at the international level via the local Australian Committee of the IWA, chaired by Prof Jurg Keller.

Key IWA events are spaced over the next two years in our region and should be of interest, including: • Off-flavours in the Aquatic Environment - Daejon, Korea.

5 - 1O October 2008

Onsite and Decentralised Sewerage and Recycling Conference

• Chemical Industries - Beijing, China. 9-11 Nov, 2008

Coming Clc., n , S u s t.,,n a blc Backyard s and Beyond!

• Sustainable Management of Sludges - Harbin, China.

18 May - 20 May 2009

1;

l

'Jo, 1o b c r

/OOH

Ben a Ila Vic t o ria

Conference Format

• Instrumentation, Control & Automation - Cairns, Australia.

14-17 June 2009

Dr George Tchobanoglous

Through presentations, workshops and papers the conference will generate a lively interplay and debate of ideas, visions, strategies and solutions

University of Californi a, Davis

• Membrane Technology - Beijing, China. 1 - 3 September 2009

Y!:nw: Ben Kele

• IWAA Stream at Ozwater - Melbourne, Australia. March 2009

Central Queensland University

The Benalla Performing Arts and Convention Centre located in North EastVictoria

• Reuse 09 - Brisbane, Australia. September 2009 • Efficient 09 - Sydney, Australia. October 2009

Greg Andrews Gle nelg Shire

• 3rd IWA Young Water Professionals Conference - Sydney, Australia. July 2010 Joint IWNAWA membership (offered with a 10% discount) affords you discounted conference registration, as well as access to Specialist Groups which focus on particular disciplines. A ful l listing of these specialties can be found on the IWA website www.iwahq.org. Some that are dynamically lead in the ASPIRE region are: • Young Water Professionals • Activated Sludge Population Dynamics • Anaerobic Digestion

.l2aw Sunday. 12 Oetober 2008 until Wednesday, 15 October 2008

Ian Allan Geocode Mapping & Planning

Be&istration from

ssso

for 3-day conference plus dinners

Conference Topics

Further Information

• Community Consultation • Decentralised Sewerage Options

Full conference pro gram, registration online and

and Management

• • • • •

Greywater Treatment and Irrigation Legal and Regulatory Issues Nutrient Monitoring and Recovery Onsitc Treatment Options Susuinable Effluent Irrigation

further information available at the conference website

.En.q.uims Pho ne: Fax: Email:

(02) H36 0055 (02) H36 0 I SS evenu@awa.asn.au

• Climate Change and Adaptation • Water Reuse.

30 SEPTEMBER 2008 water

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•

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• •

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•

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UVTA systems have distinct advantages over traditional Contact UV systems including improved efficiency and cost effectiveness .

UVTA is a division of Orica Watercare

The difference is our unique Non-Contact technology where treatment flow passes through Activated Fluoropolymer tubes surrounded by high output low pressure UV lamps. These systems are recognised worldwide for their ease of operation, reliability and low maintenance.

Our proven technology is now backed by extensive validation work against the USEPA and NWRI guidelines.

Get the UVTA advantage, call Bob Arnold on (08) 8337 0079 or visit www.uvta.com. au

awa news AWA Programs Update

to promote and oversee a nationally coordinated effort to address the skills shortage in the water sector.

The Taskforce is comprised of CEO-level representation from the water industry and related education and government sectors (viz. water utilities, consulting engineers, infrastructure, vocational sector, university sect or, the federal government sector and irrigation sector). The Taskforce members are: • Tom Mollenkopf, Australian Water Association (Taskforce Chair)

Corinne Cheeseman

• Ross Young, Water Services Association of Australia • Ken Matthews, National Water Commission • Anne Howe, SA Water

Water Industry Skills Taskforce

• Peter Mcvean, Veolia Water

Establishment of the Water Industry Skills Taskforce

• Nick Apostolidis, GHD • Bernard Meatheringham, Government Skills Australia

In March 2008, the National Water Commission (NWC), Water Services Association of Australia (WSAA) and Australian Wat er Association (AWA) hosted a CEO-level Water Skills Forum in order to develop a whole of industry strategy which ensures that the identified gaps in skills are adequately filled well into the future. The key objective of the Forum was to gain commitment to the model and resources required for achieving better skills and career outcomes for the water industry as a whole.

The Forum identified several priority actions which were consistent with many that had previously been identified by the industry. There was a strong commitment from participants at the Forum that these actions would be supported with funds from the industry on the presentation of business plans/proposals.

The establishment of the Water Industry Skills Taskforce was an outcome of the Forum. The Taskforce has been established

41~. !!!!M~rsC?~~· 34 SEPTEMBER 2008 w ater

• lven Mareels, University of Melbourne • Jolyon Burnett, Irrigation Australia Limited • Richard Mcloughlin, Chair, CoAG Working Group on Human Resources and Skills (ex officio)

Outcomes of July Taskforce Meeting The first meeting of the Taskforce was held in Sydney on 9 July 2008. At this meeting the Taskforce discu ssed the development of a strategy to guide actions that were identified at the Forum, endorsed three industry program business plans (see below) and discussed the opportunity and importance of connecting with the CoAG Water Skills Audit and Strategy project currently underway.

Detailed business plans that were presented to the Taskforce, were selected from the action plan developed by Forum participants. Proposals for the endorsed business plans

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awa news have been developed by AWA with industry involvement through reference groups, and distributed to the industry for funding support and participation. The business plans have been based on previous work done by industry reference groups th rough the Water Industry Capacity Development (WICD) network, and in the case of the Mentoring Program, AWA's Young Water Professionals network.

The programs endorsed by the Taskforce are: 1. H20z Water Industry Employment Recruitment Campaign

The H2Oz recruitment campaign wi ll develop the H2Oz brand to raise awareness of the unique opportunities offered by a career within the water industry, with its key focus to attract skill and talent to the sect or.

2. Water Industry Mentoring Program

The industry-wide mentoring program will be developed t o provide development opportunities for less experienced members of the industry, and to pass on the tacit knowledge held by experienced members. Ultimately, the program aims to provide a st ructured program wh ich ensures the transfer of knowledge and experience held in the industry, to younger and less experienced professionals, who wil l remain in the workforce in the longer term.

3. Water Industry Secondment Program

The water industry secondment program wi ll be developed to provide organisations with the opportunity to build and develop greater capacity by providing employees flexibility and development opportunities th rough secondments (to and from) other organisations in the industry. This program will be funded through WICD and provided as a benefit to the WICD Network's subscribers.

.

~

CJ!ioEnergizer Reduces Desludging Costs Reduces Trade waste costs BioEnergizer is a non-bacterium liquid biostimulant that accelerates the breakdown of sludges in wastewaters and provides nutrients and biostimulants to balance and accelerate existing microbial activity.

BioEnergizer Lowers BOD/COD levels and Reduces Odours Advantages include:

Used in:

• No heavy machinery on site

• Pump stations and uplifts

• No dewatering required

• Industrial wastewaters

• No sludge stockpiles

• Grease traps

• No sludge transport costs

• Pulp and paper mills

• No sludge disposal issues

• Dairy farms and piggeries

• Enhanced wastewater biology

• Food processing plants

• Reduced foaming

• Isolated communities

Before BioEner izer Solids virtually filling entire lagoon. Lagoon out of effective service.

CoAG Water Skills Audit and Strategy

After 1 month

The Council of Australian Governments (CoAG) has recently undertaken a skills audit and is currently developing a strategy to ad dress water ski lls issues. To ensure that the Taskforce and CoAG's activities are comp lement ary, the Chair of CoAG's Worki ng Group on Human Resources and Skills is on the Taskforce as an ex officio member. The Taskforce is currently participating in the consultation phase of the development of CoAG 's water skills strategy and provided feed back on the draft strategy at a special Taskforce teleconference meeting on 12 August 2008 before it is was submitted to the Australian Government (DEWHA).

The strategy will be presented to CoAG in October.

solids beginning to break up, water beginning to flow.

'

After 2 months significant reduction in solids, water now flowing through system.

The Taskforce will continue to move forward in parallel with the CoAG project and it is the intention of the Taskforce and the Government to work collaboratively to reduce the impact of the water skills shortage, through an appropriate combination of Government and Ind ustry actions and strategies.

Updates and progress wi ll be given through AWA's publications and directly through the Water Industry Capacity Development {WICD) Network. If you are not currently receivi ng updates on skills and related issues directly and would like to be kept informed please email ccheeseman@awa.asn.au with your details.

I

After 4 months sludge blanket almost gone.

High water flow, lagoon returned to operational status.

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OZMOTECH tiative

water SEPTEMBER 2008 35

awa news YWP Update

We now have an elected ACT YWP Committee, well done to Zoe Moore and Ginni Glyde for their initiative getting YWPs off the ground in our nation's capital. Zoe Moore is now the President of the ACT YWP Committee as well as being the ACT Representative on the YWP National Representative Committee (NRC).

Nie Morgan has recently stepped down as the Northern Territory YWP Representative after being involved on the NRC for a number of years. Welcome to Joanna Lee our new NT NRC Representative.

Erin Cini The YWP Specialist Network recently compi led a report on our 2007-08 activities. Looking back it was an excellent year for YWPs, membership of our network increased by 34% to 620 members and we contin ue to raise our profile within AWA and the water industry by holding interesting, diverse and exciting events, and by engaging with all members of the industry. We plan to continue to strengthen our network, with a particular interest in networking and capacity development.

Our network would not be the success it is without the volunteer YWPs that form our National and Branch Committees, the support we receive from the AWA Board, AWA Branches and the AWA staff. I would like to thank all those involved in the YWP Network for their hard work.

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The Micron Horizontal fi tter's spherical ends are designed to give uniform flow from both inlet and outlet collection assemblies. The filter's hydraulic design provides adequate distribution to evenly expand the fitter bed during backwash and the entire media bed is utilised during the filter cycle.

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Queensland YWPs recently attended the largest ever AWA OLD Gala Dinner. Our thanks to Tyco Water who sponsored a table of YWPs, giving us the opportunity to network with the who's who in the water industry. The QLD YWP Committee also recently held annual elections, where the hard working Graeme Wallace handed over the Presidency to Shoshana Fogelman who has had a long involvement in the YWP Network, in particular in setting up the existing AWA mentoring program. Kirsten Newnham is taking on the role of QLD NRC Representative - we lcome Kirsten.

The recent WA YWP Speed Networking event was a great success - with lots of business cards being exchanged and new networks formed. WA has an event planned for November that I am sure will gain a lot of interest (so get in quick) - a tour of the Little Creatures Brewery - contact wabranch@awa.asn.au for details.

South Australian YWPs recently held another thei r annual YWP Forum - Forging a Future in Water: Career skills for all water professionals. The Forum included presentations by executive water industry members, on topics including leadership in water, managing your career, commu nication and mentoring. The Forum also showcased the work of YWPs in the industry.

The NSW YWP Committee's very successful annual Seminar Series, The Future of Water - Technology, Power and Money, continues on Wednesday September 17, looking at the implications linking water, energy and climate change. Next month, speakers wi ll examine Water Markets with a focus on pricing and competition in the NSW water sector.

For those YWPs looking at a moving into up the career ladder (probably most of us!) get ready for the Victorian YWP Committee's evening seminar - YWPs Fast Track to Management on Thursday 13 November.

For more information about what is happening in the YWP Network email me at ywp_president@awa.asn.au or contact your local Committee: ACT ywp_act@awa.asn.au

NSW ywp_nsw@awa.asn.au

NT ywp_nt@awa.asn.au

QLD ywp_qld@awa.asn.au

SA ywp_sa@awa.asn.au

VIC ywp_vic@awa.asn.au

WA ywp_wa@awa.asn.au

WAT E R ' ' ~

!!~~'.!! L,.....::

_ _ _ _ . r....

36 SEPTEMBER 2008 water

After being selected as the best paper presentations at the IWA AWA 2nd Australian YWP Conference held in Brisbane earlier this year Catherine Port and Matthew Brannock recently travelled to the IWA YWP Conference held in Berkeley in the USA. Look out for a report on the Conference in the next YWP Newsletter due out this month.

In TAS and want to get YWP activities going? Contact ywp _president@awa.asn.au

AWA

International Centre of Excellence in Water Resources Management

SHORT COURSE

Australian Water Industry Essentials Th is compre hensive 2-day course cove ring w ater ma nagement in Australia w ill provide participants with an overview of t he cu rrent tech nical, economic, environmental, legislative and social issues associated w ith t he Austral ian water scene.

WHEN Melbourne 25 & 26 September, 2008

Brisbane Perth

'' Presentation by experienced water professionals Comprehensive course notes Glossary of terms and useful read ings Who's who in the water zoo overview Pre and post course quiz Networking with other water industry professionals â&#x20AC;˘ Small group sizes to allow greater interaction t Lunch and mid session tea breaks t t t t t t

Continuing high levels of interest in water issues - technical, operational and policy - and increased job mobility have resulted in unprecedented interest in a structured short course providing a sound overview of water management in Australia.

AWA is pleased to partner in presenting this course; one that is uniquely positioned to deliver a sound working understanding of the key issues in water. , , Tom Mollenkopf Chief Executive Australian Water Association

'

For further infonnation Contact ICE WaRM

Tel: +61 8 8236 5200

Email : tra ining@icewarm.com.au

23 & 24 October, 2008 11 & 12 November. 2008

www.icewarm.com.au

â&#x20AC;˘

An Australian Government Initiati\'c

awa news Water Education

Water Education Network (WEN)

Patricia Dames Community Education Coordinator

The WEN is open to anyone with an interest or involvement in wat er education. The network aims to link existing networks and broaden communication across the fu ll range of educators including school water education network education, tertiary education, vocational education/training, community education etc. Members of the WEN contribute and receive information on water education programs, initiat ives and events nation-wide.

How time flies when you 're having fun! Recently I went to Darwin where I attended the Australian Association for Environmental Educators conference, and also held a WEN Network Meeting. It was a great opportunity to meet a group of people who are dedicated to environmental education and share their innovative ideas on broadening the capacity of the network.

I have also travelled to Stockholm with Gwylim KlippelCooper who was the 2008 Australian representative competing for the 2008 Stockholm Junior Water Prize. During this time I have also been lucky enough to attend the World Water Week conference wh ile in Stockholm and a variety of presentations.

The theme for the 2008 conference is 'Progress and Prospect s on Water: For a Clean and Healthy World.' The United Nations declaration of 2008 as the International Year of Sanitation has promoted a focus on sanitation - an issue which affects over 2.5 billion people across the world.

Through regular meetings across the cou ntry, the WEN aims to create networking opportunities and support for those involved and/or interested in water education.

Sharing of resources and information is a key part of the network and meetings provide an opportunity for members to make contact and develop relationships to enhance the contin ued sharing of information and knowledge. www.awa.asn.au/wen

during a special ceremony. Contestants from both Russia and Sri Lanka were awarded Excellency Awards. To see the paper written by Gwylim and Dayffyd Kli ppel-Cooper visit the AWA website.

The conference also provided the platform for awarding of prestigious prizes such as the Stockholm Junior Water Prize and the Stockholm Water Prize. Professor John Anthony Allen was awarded the 2008 Stockholm Water Prize for his concept 'Virtual Water.' Read more below about the Stockholm Junior Water Prize.

The AWA's Australian Stockholm Junior Water Prize provides a platform t o raise the profile of the water industry and an interest in water education and careers. The Australian SJWP, open to all high school students nationally, aims to support young students in water conservation, water protection and water resources management. Entries for the 2009 competition are now open. For information about the award and criteria for entry visit the AWA website at www.awa.asn.au/ajwp, or email pdames@awa.asn.au to request a copy of the flier. Entries close 8 December 2008.

2008 Stockholm Junior Water Prize

National Water Week 2008

The Stockholm Junior Water Prize is an opportunity for students to be recognised for their work on water research project s. This year 61 contestants from 31 countries attended World Water Week in Stockholm to compete for the international honour.

Clean Water - Essential for Life!

Gwylim Klippel -Cooper represented Australia with his project 'Water Filtration Utilising Sea Shell s' and also participated in a week long cultural exchange. The variety of topics was broad and the judging panel commended all students for their innovative ideas and high standard of work, but could only award one winner.

Joyce Chai from the United States was awarded the 2008 Stockholm Junior Water Prize for her project ' Modelling the toxic effects of Silver Nanoparticles under varying Environmental Conditions.' The prize Gwylim Klippel-Cooper (right) receiving a was awarded by Crown Stockholm Junior Water Prize certificate Princess Victoria from Sweden's Crown Princess Victoria.

38 SEPTEMBER 2008 water

Get geared up for National Wat er Week (NWW) with a heap of free resources and downloads available on the NWW website.

There are so many ways to celebrate wat er and National Water Week provides a great opportunity to focus your activities around our precious water resources. The 2008 theme "Clean Water: Essential for Life!" gives you the opportunity to explore the many different ways in which clean water is important to people, plants and animals.

Check out the 2008 NWW website at www. nationalwaterweek.org.au for a heap of information and resources for use by community, schools, industry and media to help make your NWW event easy and fun to run.

Water

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regular features

awa new members New Members AWA welcomes the following new members since the most recent issue of Water Journal:

D.Gough , F.Gouws, A.Hawthorne, I.Jukic, A.Lee, A.Lovatt, J.Mingay, A.Miszalski, K.Palos, J.Paterson, A.Petterson, B.Turner, P.Walsh, G.Warren, H.Watts QLD

NSW Corporate Bronze Hydro Innovations pty Ltd 1/26 Day Street North Silverwater NSW 2128 Telephone: 02-9647-2700 Fax: 02-9647-2709 QLD Corporate Gold BMT WBM pty Ltd PO Box 203 Spring Hill QLD 4004 Telephone: 07-3831 -6744 Fax: 07-3832-3627 Utility Gold Midell Water Solutions pty Ltd PO Box 2377 Fortitude Valley BC QLD 4006 Telephone: 07-31 00-1357 Fax: 07-3100-1362 Corporate Silver IDM Partners pty Ltd GPO Box 2938 Brisbane QLD 4001

P.Bates, P.Burrell, G.Capati, M.Crozier, G.Floridia, T.Harrison, P.Lutz, J.Martin, T.Moore, A.Palmer, K.Pattingale, P.Surtees, T.Talbot, C.Uhrig SA B.Binks, J.Dawe, D.Duncan, L.Hobart, A.Lawson, A.Lourens, B.McDonald , H.Pointer, M.Schilling, J.Skirrow, P.Yu TAS A.Owers VIC A.Atchison, L.Brown, G.Cheah, N.Clements, A.Connell, D. D'Aspromonte, A.Deppeler, L.Dinh, A. Favero , L.Fouche, M.Frame, W.Fraser, P.Gin, J.Hickey, A. Hickey, 1.Jungic, T.Kuen, HS.Low, A.Mclellan, P.Meyers, A.Minas, B.Mitsch, M.Noyce, S.Pickard, J .Pruyn, T.Slater, S.Smith, H.Sunarko, M.Tynkkynen, J .Wyatt WA K.Agenson, M.Batty, S.Brown, E.Burns, L.Feuilletin, B.Haak, K.Lynch , V.Moscovis, S.Trott Overseas

Telephone: 07-3229-9232 Fax: 07-3229-9233

S.Couper, B.Davison, L.Maclennan

Linkwater PO Box 1045 Spring Hill QLD 4004 Telephone: 07-3270-4004

NSW NU H.Zardari

Corporate Bronze SEQ Water Grid Manager PO Box 16205

NT L.Tan

City East OLD 4002 Telephone: 07-3033-0785 Fax: 07-3405-0373

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ACT L.McPhail

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NSW

QLD A.Constantinou, K. Liew, N.Mead, M.Pearce, P.Sodhi VIC F.Ginnivan, G.Aice, D.Sirikhant, D.Southcombe, B.Streader

ACT

WA C.Ng, Y.Salamatin, J.Scally

A.Clarke, C.Hepplewhite, M.Sullivan NSW M.Beckwith, C.Bourke, I.Burrows, H.Bustamante, B.Butturini , J.Chiang, A.Coyte, K.Dahl, M.Daly, A. Davies, E.De Aooy, A.Dijanosic, N.Dinnen, C.Doolan, S.Dyer, I.Gabriel, K.Gokal, M.Gomes, T.Gooley,

If you think some new activity would enhance the membership package please contact us on our national local call number 1300 361 426 or submit your suggestion via email to membership@awa.asn.au.

carbon reduction

CARBON POLLUTION REDUCTION SCHEME

By Andrew Speers Details of the proposed Carbon Pollution Reduction Scheme are beginning to emerge. In June the Draft Report of the Garnaut Climate Change Review was published followed in July by the Carbon Pollution Reduction Scheme Green Paper. These two documents set out, respectively, the context of Australia's response to climate change, and the framework for an Emissions Trading Scheme (ETS).

The Garnaut Climate Change Review The Garnaut Report argues strongly for Australia to implement a broadly based ETS. Prof. Garnaut's views reflect those of 'most reputed specialist s in climate science, in Australia and abroad, on the risks of climate change' and the orthodoxy that market -based approaches wi ll be most efficient. While he acknowledges that there are large uncertainties in our understanding of the effects and magnitude of climate change, he holds - as does the Intergovernmental Panel on Climate Change - that anthropogenic climate change is almost certain and potentially extremely damaging. Steps to encourage mitigation of emissions at the least cost are warranted, particularly as this country is already hot and dry (small variations in cl imate are more damaging to us than to other developed countries) and because cl imate change has the potential to cause regional political instability.

Prof. Garnaut argues that Australia should take action as a stimulus to international cooperation. He notes that the impact on the Australian economy should we maintain an emissions trad ing scheme over many years in the absence of global cooperation to mitigate greenhouse emissions may be high.

However he suggests that if Australia implements a broad, market-based scheme to reduce emissions we can help to accelerate progress towards an effective international agreement, thereby reducing the relative impacts on the Australian economy. He argues that the short-term cost to the economy is justified as we have benefitted from the Asian econ omic boom currently underway, the source of a significant increase in greenhouse gas emissions in the past 2 decades.

The Draft Report is one of a suite of documents to be produced by Prof. Garnaut. In the Draft Report he states his determination to create a transparent basis for future policies by undertaking extensive econometric modelling to reveal the costs and benefits of an ETS. Thu s, the Draft Report will be followed imminently by a Supplementary Draft Report which will set out the modelling underpinning Garnaut's fi ndings and which is to address questions arising from that modelling. A Final Report will then be released in September.

.

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.

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Carbon Pollution Reduction Scheme (CPRS). Comment is invited on the Green Paper, and AWA has made a formal response.

The threshold for inclusion in the CPRS w ill be 25kt COre 1/year meaning that about 75% of the nation's greenhouse gas (GHG)2 emissions wi ll be covered by the scheme, representi ng the output from about 1000 companies.

At th is threshold, a number of wastewat er treatment plants may be included, although t he precise figure can't be determined until more information is received on the way in wh ich emissions are t o be calcu lated.

The industry sectors to be included in the CPRS are: Stationary Energy; Transport; Industrial Processes; Fugitive Emissions from Fuel Production; Forestry and Waste (including Wastewater). Upon establishment, a defined number of permits w ill be availab le representing the total GHG emissions 'cap' for the economy {1 permit = 1 tonne COre). These permits will be auctioned and it is proposed that they will be available for anyone to purchase. Emissions-intensive industries and tradeexposed industries will receive free permits as a transitional measure to prevent undue impact on these sectors and t o ensure they do not become uncompetitive internationally.

The Carbon Pollution Reduction Scheme Green Paper

The emissions 'cap' will be reduced over time in line with the Government's requirements. To ensure stability in the market, the cap for any one year wi ll be announced 5 years in advance and the range within which the reduced cap wi ll fall will be announced 10 years in advance, beginning at the end of the 5th year (see diagram).

The Carbon Pollution Reduction Scheme Green Paper sets out the Government's preferences for an ETS referred to here as a

The Government's view - also put forward in the Garnaut Report - is that offset credits should not be included within the

1. CO 2 or CO 2 equivalent 2. The GHG included in t he ETS will be those included in the Kyoto Protocol, namely: CO2 , SF6 , CH4, N2 O, HFCs, and PFCs

40 SEPTEMBER 2008 water

feature articles

CPRS scheme. Offset credits might, for example, include investments to reduce carbon emissions from facil ities not included in the scheme or purchase of, say, forests for carbon sequestration. The Government's argument is that offset credits are difficult to quantify and monitor and that a CPRS which includes only emissions from the regu lated facility or company is administratively more transparent and efficient than a scheme which includes offsets from unregulated sites. Offset cred its may be available in the voluntary market, but these would not offset the CPRS. That having been said, a water company operating a facil ity that is captured by the CPRS may be able to generate CPRS permits if it is undertaking forestry operations within its catchments that sequestor carbon .

It is proposed, however, that companies could purchase carbon pollution permits through ETS schemes operating in other countries, as long as the Government has satisfied itself that the scheme throug h which the purchase is to be made is legitimate and properly reg ulat ed. The capacity to purchase permits offshore potentially red uces costs to Australian industry.

Funds raised through the CPRS are to be used to mitigate the regressive effects of the scheme on households, protect emissions-intensive, trade-exposed industries and to create a Climate Change Action Fund to assist industry in its transition to a low carbon economy.

The water industry may be able t o access these funds.

Impacts on the Water Industry and Industry Response The CPRS wi ll have direct and indirect effects on the water industry. In the scheme of thi ngs, the contri bution of wastewater treatment - the only water industry activity that would fall within the threshold of the CPRS - to Australia's GHG emissions is small (0.39% of total emissions). The industry overall is, however, a significant consumer of electricity. Where the generation of such energy leads to the generation of GHG's, prices could be expected to rise.

Most com panies whose facilities wi ll fal l within the CPRS will soon be reporting their emissions, as required under the National Greenhouse Energy Reporting System (NGERS). This scheme, which began on 1st July 2008, covers the owners of facilities emitti ng more than 25kt CO2 -e/year or corporations emitting more than 125kt CO2-e/year (in year 1). Th is means that some wat er companies whose facilities do not fall with in the CPRS will still be required to report under NGERS. (Further information is available at www.climatechange.gov.au/ reporting/index.html).

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AWA proposes to convene a number of workshops on the CPRS when the Government's preferred position becomes clearer. Information about the times and venues for these events wi ll be included in AWA News as soon as they are organised.

There are significant challenges for the industry in preparing for the implementation of an ETS. AWA's active engagement in the design process should ensure that a scheme emerges that is administratively efficient and effective.

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CRC for Water Quality and Treatment

CRC FOR WATER QUALITY AND TREATMENT - ACHIEVEMENTS A Gackle

On June 30th 2008 the CRC for Water Quality and Treatment ended after 13 years. The last Board meeting was held in Melbourne on June 16th, followed by a farewell dinner; a very sociable and noisy event with many CRC friends and stalwarts present - both current and past. Special tribute was paid to the indefatigable Chairman Emeritus Professor Nancy Millis, who made her farewell speech alongside Don Bursill and Dennis Steffensen, the first and last CEOs of this CRC. But looking at the CRC clearly and without sentiment, what did it achieve?

The answer might depend on who you ask, but to answer it fairly it is probably necessary to consider first the environment into which the CRCWQT was born.

By the early 1990s most urban water supply and management in Australia had been, or was being, privatised, and inhouse research services were cut back or contracted out. The industry had been depleted of an enormous amount of corporate and indust ry knowledge and expertise. Water supply and safety were not the high profile matters they are today.

The commonwealth government's CRC Programme in 1991 provided the bestso-far strategy to align and focus more closely the interests and efforts of the public and private sectors for national benefit. Supported by successive governments since then it remains an effective vehicle for forgi ng alliances and establishing linkages between and among industry and research groups.

This worked particularly well in the water supply industry.

The CRC enabled the building of a drinking water community of interest. It linked the health, regulatory and research sectors in a dialogue and collaboration to examine the cat chment to tap continuum.

This broad-brush overview of issues has served us well in a stimulating and useful research portfolio. As shown in the table the research was an integrated matrix of research themes and management approaches which provided a comprehensive effort targeted at areas of greatest need .

42 SEPTEMBER 2008 water

By the time t he lights go out in the CRC offices at the end of the year, there will be more than 80 significant published project reports (which are now freely available on the website) along with other technical reports, occasional papers, workshop reports, abstracts from more than 100 CRC PhD student theses and more.

and is widely used to manage risk in Australia

An important measure of the success of the CRCWQT has been the increased support from the water industry. The membership grew from 17 in 1995 to 29 plus 20 associates in 2001. Most importantly support has been secured from 40 industry and research agencies for an independently funded centre, Water Quality Research Australia which wi ll carry on the work of the CRC. WQRA wi ll also allow the continued transfer of the outcomes from the CRC to the end users.

4. Australian operators have an improved capacity to manage and mitigate risk to water quality

2. The Framework provided (and still does) the rationale fo r identifying knowledge gaps and determining research priorities 3. WHO water safety plans are modelled on those developed in Australia

5. The industry is more cost effective using less or better chemicals and optimising treatment 6. The CRC's Educat ion and Training Program has nurtured and sent forth a large number of talented and industryready employees - at a time when they are desperately needed.

A definite advantage of WQRA's business model is that it wi ll avoid some of the management challenges encountered in the CRC, of conflicting demands upon busy staff seconded from a parent institution. The CEO and Program Managers in WQRA will be employed by WQRA.

The drinking water landscape has changed over thirteen years - literally and metaphorically. Water may well be the flavour of the millennium, as we grapple with drought, pollution, etc.

There are many new players on the scene. We should all be glad of this , despite the likely jostling for funds and the best people.

But the CRCWQT has other successes of which we are truly proud.

The Author

1. The Framework for Management of Drinking Water Quality was jointly developed by the CRCWQT and NHMRC

Angela Gackle is Communication Manager, CRCWQT, email angela.gackle@sawater.com.au

The table below shows the areas in which research was conducted in the CRCWQT. Across the top are the research themes and on the left are shown the program disciplines. The shaded cells indicate that research was carried out by a program group on that theme. For instance, all programs were involved in research on micropollutants.

Epidemiology Toxicology Measurement Catchments Reservoirs Treatment Distribution Measurement

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nanotechnology

GOING NANO - NANOTECHNOLOGY IN WATER TREATMENT

0

John Poon & Rob Huehmer, CH2M HILL Australia "Developments in nanotechnology are not a result of natural evolution of technology, but due to a new technology paradigm" says CH2M Hill's John Poon.

Nanotechnology deals with research and technology development with matter that is about 1 to 100 nanometres in diameter.

Nanotechnology helps to understand the nano-structures of matter and then enables the creation of products, devices and systems with new properties. So promising are the potential advancements anticipated in water treatment, the American Water Works Association (AWWA} hosted a webcast on July 23rd, 2008 examining the applications and implications of nanotechnology in water treatment.

Dr Nora Savage, of t he United States Environmental Protection Agency (USEPA) introduced nanotechnology to webcast participants, and illustrated how pervasive nanotechnology has already become. Several common products with nanoparticles on the market include: display screens; automobiles; nano Silver Wash washing machines; and sporting equipment. Dr Savage indicated that understanding of nanoparticles, techniques in imaging, measuring, modelling, and manipulating matter at this scale allows development of new materials for new applications.

Some important characteristics of nanoparticles presented include large increase in surface area per unit mass (- 100 m2 per gram); and quantum effects - mechanical, electronic, photonic, and magnetic properties.

Common chemical elements used in water treatment are fullerenes, carbon nanotubes, titanium oxide, zinc oxide and other layered compounds.

United States National Nanotechnology Initiative The National Nanotechnology Initiative (NNI) in the United States (US) was c reated in 2001 as a federal initiative to provide a multi-agency framework to improve human health, economic well being and national security. The NNI invests in fundamental research to further understand nanoscale phenomena and

44 SEPTEMBER 2008 water

expected to grow at 10.7% annually.

According to Dr Hoek, nanoparticles may introduce new products in c atalysis and in separation processes applied to water treatment. Several properties of nanoparticles which will be useful in developing new products are of use: higher surface area; quantum effects mechanical stability; c ontrolled structure; higher permeability; fouling resistance; sorption selectivity; and biocidal reactivity and sensing interfaces.

UCLA's Eric Hoek is at the forefront of research on impregnating nano-particles on membranes.

facilitates technology transfer. Twenty five US government departments and agencies are part of this initiative, including environmental, defence, research, health and safety and justice.

Dr Savage indicated that USEPA's interest in nanotechnology is to evaluate potential harmful effects to human health or the environment through regu latory responsibilities. EPA is also interested in considering environmental benefits and impacts as new technologies develop.

EPA's research needs in nanotechnology are summarised in the White Paper on Nanotechnology issued in 2007. Based on the white paper, EPA will focus on: t he research needs grouped as, environmental fate, transport and transformation ; exposure to nanoparticules; and monitoring and detection methods. Nanotechnology opportunities exist in drinking water disinfection, groundwater remediation and surface water protection.

Dr Eric Hoek of t he University of California - Los Angeles (UCLA) presented information dealing with the market growth of TiO2 and iron nanoparticles.

Titanium oxide shows promise for gas phase catalytic destruction of cont aminants and for creating selfcleaning surfaces. Fouling of catalytic surfaces in aqueous media may inhibit applications to water treatment. Titanium oxide coupled with ultraviolet disinfection shows promise in DOC removal but energy consumption during the process needs to be optimised. Nano-scale iron particles have also been successfully used in in-situ remediation of detoxification of pesticides.

Based on recent studies, the market for advanced drinking water technologies is

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Environmental Concerns Exist USEPA is concerned about the long-term fate and impact of nano-particles in the envi ronment. As part of their strategy, Dr Savage indicated that long-term studies on impacts on human-health and environmental are requ ired , as nanoparticles have the ability to cross through biological membranes (for instance the blood-brain interface).

Advanced Membrane Technology The major focus of membrane nanotechnology research is low-energy desalination, according to Dr Hoek.

Several other advanced membrane research interests include: • Tunable/active/biomimetic membranes.

Nanotechnology-Enhanced Water Treatment

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• On demand catalytic reactivity.

• Integrated contaminant sensing.

• Active and passive fouli ng resistance.

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nanotechnology • Self cleaning and regenerating surfaces • On-site/ in-situ chemical generation.

Dr Hoek indicated that compared to ceramic and polymer membranes, nanocomposite membranes - comprising inorganic nanoparticles embedded within polymeric films - offer numerous potential advantages. While improving selectivity and stability, they are easier to process, flexible and can have high packing density. These new membranes have some disadvantages of materials compatibility and loading limits of nanoparticles.

In microscopic tests, aquaporin-based biomimetic membranes and carbon nanotube membranes have been shown extremely high flu xes compared to traditional polymeric RO membranes; however, to date there are no reports of macroscopic samples of these advanced membrane materials being fabricated or tested . Theoretical studies suggest both materials could produce membranes with desalination-type separation performance. Thin film nanocomposite membranes have been hand-cast in macroscopic sample sizes and exhibit

separation performance that is similar to commercial BWRO and SWRO membranes, but with significantly higher flu x and signs of fouling resistance.

Next-Generation Reverse Osmosis Membranes In the past decade, developments in membrane materials and pretreatment products over the years and introduction of energy recovery systems have continuously decreased the unit cost price of SWRO water production .

However, the standard and maturing technology has led to diminishing cost returns on new developments. A revolutionary technology development is needed to change this trend . Currently, efforts are underway to commercial ise next-generation reverse osmosis membranes. Dr Robert Burk, of NanoH 2 0, indicated that nanotechnology can be used as a leverage to improve RO membrane performance by: reducing pretreatment needs; reducing energy consumption; reducing chemical consumption and proving flexibility in system design. This will reduce installation and O&M costs. Facility footprint will also decrease.

Work by Dr Hoek and NanoH 2 0 , indicates that nanoparticles incorporated into the structure of conventional polymer membranes results in 100% increases in productivity while reducing fouling . These films are then rolled in the form of conventional membrane modules.

While nanoparticles add about 5% to the capital cost, the desalination process with membranes uses 85 % of overall plant energy. A more permeable and fouling resistant SWRO membrane type would significantly decrease energy consumption .

Current commercial products are largely based on 30-year old chemistry .

Several companies (such as NanoH 2 0) are applying research on nanotechnology to commercial products . These new membrane modules that use nanotechnology wi ll incorporate these new developments while preserving the current manufacturing infrastructure.

Cost of installing a desalination plant can be significantly reduced with advances in new products.

Picture and caption kind ly reproduced with the permission of WME En vironment Business Magazine.

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Seminar Objectives At the completion of this seminar, each delegate should be able to: •Identify common centrifugal and positive displacement pump types and their components.

•Understand pump, associated component, hydraulics and slurry terminology.

•Select the most appropriate pump type, make and model for a particular application .

•Be competent in reading and using pump performance curves.

•Understand cavitation, how to design it out of the system and how to correct an existing system experiencing cavitation related problems.

•Specify the correct installation configuration for a particular pump type of application .

•Install, commission , operate and maintain common pump types.

•Troubleshoot pump problems .

•Feel comfortable when dealing with pump suppliers and be able to double-check their pump selections.

Delegate Pre-Requisites It is a requirement that each delegate has an understanding of mechanical components. A basic understanding (trade level) engineering maths would also be advantageous.

DAY1

DAY2

BACKGROUND INFORMATION Terms and Definitions Fluid Properties Basic Hydraulics Theory and Calculations Cavitation Friction Losses in Pipes and Fittings Pump Classification and Examples Pump Selection Guidelines

PD PUMPS (CONTINUED) Common PD Pumps - (Gear, Lobe, Progressive Cavity, Piston, Diaphragm, Peristaltic) Selection Guidelines Troubleshooting

CENTRIFUGAL PUMPS Components, Types and Examples Affinity Laws and Characteristic Curves Matching the System to the Pump System Curve Calculations Viscosity Effects Parallel and Series Pumping Troubleshooting INTRODUCTION TO CENTRIFUGAL SLURRY PUMPS Slurry Classifications and Rheology Slurry Characteristics Solids Content and Settling Velocities Typical Components and Assemblies Characteristics Curves Selection Criteria POSITIVE DISPLACEMENT (PD) PUMPS PD Pump Theory Typical System Curves Comparison to Centrifugal Pumps

Who Should Attend?

This seminar has been designed for: •Process, Design, Project and Consulting Engineers.

•Line Managers and Supervisors.

•Maintenance Technicians.

•Pump Sales Representatives.

•Anyone who needs to select, specify, commission, install and/or maintain pumping equipment.

INSTALLATION & MAINTENANCE Foundations and Bases Alignment Recommended Piping Configurations Condition Monitoring Preventative Maintenance General Installation and Maintenance Tips

•Certificate of Attendance - which states the number of hours of training and serves as documentary proof of attendance.

18 & 19 November 2008

Liquid Piping Fundamentals Seminar Brisbane

20 & 21 November 2008

25 & 26 November 2008

Melbourne

27 & 28 November 2008

The Chifley at Lennons, Brisbane The Vibe Savoy Hotel, Melbourne

The Vibe Savoy Hotel, Melbourne

Perth

PUMP DRIVES General Overview Canned and Magnetic Setups Belts, Gearboxes, Mechanical Variators Electric Motors and Inverters Other Drive Types

•The "Pump Fundamentals" Training Manual - a reference manual comprising theory, worked example problems, tables and charts, illustrations etc based on the training seminar outline . This manual has been designed to be a valuable future resource for the office, workshop, factory or plant.

The Chifley at Lennons, Brisbane

Melbourne

SEALS AND PACKING General Overview Components and Types Applications and Selection Installation , Maintenance, Troubleshooting

Seminar Materials

Pump Fundamentals Seminar Brisbane

EDUCTORS (JET PUMPS) Principle of Operation Applications

2 & 3 December 2008 The Novotel Langley Hotel Perth

Perth

4 & 5 December 2008 The Novotel Langley Hotel Perth

BACKGROUND INFORMATION Terms and Definitions Fluid Properties Basic Hydraulics Theory and Calculations Cavitation & Water Hammer Friction Losses in Pipes and Fittings Scaling Pipe Sizing Methods Pipe Manufacturing Methods SELECTING PIPE AND FITTINGS Common Codes and Standards Materials of Construction Connections - Screwed, Flanged etc Gaskets and Jointing Materials Fittings VALVES Common Valve Types - (Ball, Butterfly, ,lobe, Gate, Pinch , Angle, Needle, Check, Pressure Reducing , Solenoid, vacuum/Pressure Break, Pressure Relief, Diaphragm, etc) Materials of Construction Valve Actuators Valve Selection and Sizing Guidelines Control Va lve Selection and Siz ing INSTRUMENTS pical Instruments Found in Piping Systems Selection Guidelines

DESIGN & DRAFTING Piping Specifications Drafting Symbols Process Flow Diagrams, Piping & Instrumentation Diagrams, Line Lists, Plot Plans, Layouts, Isometrics, Spool Drawings GUIDELINES FOR PIPING LAYOUT General Overview Maintenance and Operating Requirements Process Requi rements Safety Considerations PIPE SUPPORT SYSTEMS General Overview Rigid , Variable and Spring Supports Applications and Selection Introduction to the Design of Pipe Supports INTRODUCTION TO PIPING DESIGN LOADS Sustained, Occasional and Thermal Loads Basic Manual Calculation Methods for Simple Loading Problems MISCELLANEOUS TOPICS Insulation and Tracing Fabrication and Erection Filters, Strainers, Static Mixers etc

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biosolids

BIOSOLIDS IV, ADELAIDE June 2008 Report by E A (Bob ) Swinton The first Biosolids Speciality Conference was organised by Diane Wiesner in 2002 and successive conferences have demonstrated the interest in this topic, particularly since it c onstitutes some 4050% of the cost of operation of a typical WWTP. The conference date was very appropriate because the comprehensive National Biosolids Research Program is now complete, and all reports are available. This conference was sponsored by Arkwood Organic Recycling (a leader in biosolids transportation and spreading, evidence of the importance of land application as a beneficial use), and also the Water Corporation. It was attended by over 120 delegates, with six useful exhibitors.

At the closing plenary of Biosolids Ill (reported in Water August 2006) it was mentioned that the 2008 conference needed more emphasis on technologies and uses, and Diane Wiesner had certainly organised papers to suit.

International The conference opened with a review of practices in UK, Europe and USA. Peter Matthews, formerly Deputy MD of Anglian Water, and now Chair, Sustainable Organic Resources Partnership (SORP), reported that in UK over 70% of sludge is treated to biosolids standard and used for land application, increasing from some 50% in 1990. It is steadily rising despite some adverse public perceptions, in part this increase is driven by the perceived benefit of locking of carbon in soil (despite it being an insignificant percentage globally). Landfill regu lations are increasingly stringent and incinerators are not popular, though some industrial cities have to operate them.

He reviewed the history of legislation in both UK and EU . When realising that all countries face the same problems, in the 1990s the Global Biosolids Network was formed. The International Water Association, European Water Association and Water Environment Federation were very active, in particular, but many other national organisations participated as well. The Network was very productive,

50 SEPTEMBER 2008 water

Pictured at the Biosolids IV conference in Adelaide are (L-R) Tom Evans (UK), Peter Matthews (UK) and Stephen Smith (UK).

the Global Biosolids Atlas being a very good example of the products. The second edition of this is being produced as a result of the IWA Biosolids Conference in Moncton in June 2007.

In the UK, regulating biosolids practices took a step forward in 1996 when the Environment Agency, EA, was created. However, the major supermarkets started to ask questions and eventually the Safe Sludge Matrix was set up in 1998 as a guideline for safe land application.

However new EU policies and national laws were tighten ing the regulation of all organic wastes applied on land, and further restrictions were planned in Europe and the UK on the uses of biosolids.

In 2003, the Environment Agency, along with the Chartered Institution of Water and Environmental Management and the Agricultural Development Advisory Service supported the establishment of the Sustainable Organic Resources Partnership, SORP, as a registered company organisation with some 50 members. Its objectives are to promote safe, sustainable, trusted and welcome recycling of organic resources,

with biosolids on the same footing as other organic wastes, such as feedlot manures. It has a small management board, but the real work is done in the technical network. Trust is at the heart.

Language is important - it is how something is said as much as what is being said. So "sludge dumped on land" creates a mindset different to "biosolids used in agriculture". SORP would be very happy to play its role in resuscitating the Global Biosolids Network, but maybe this time as the Global Organic Resources Network.

Tim Evans, UK Consultant, in a later paper reviewed the UK and EU moves to establish quality protocols so that land application can be beyond reproach. The Safe Sludge Matrix is voluntary, not legally binding, and a few companies , including a whiskey distiller, have imposed a no-biosolids clause in their grain contracts with farmers. The aim of the water companies is to establish enough confidence that this decision be reversed by providing biosolids which wou ld comply with a British Standard of 'Accredited Quality'.

He also delivered a comprehensive review of innovations in sludge

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biosolids treatment, which is summarised separately in this issue.

THE ABP - WHERE ARE WE AT?

Ian Pepper, Director of the National Science Foundation Water Quality Center, University of Arizona, reported on t he situation in USA. Currently about 60% of all biosol ids are land-applied in the United States, most ly Class B as a 20% solids cake, or as liquid biosolids (- 5-8% solids). However, in some areas of the US such as parts of California, public concern has resulted in the banning of land -application of Class B biosolids.

Because of t his concern, the National Science Foundation Water Quality Center has sponsored studies on major biologi cal issues and the long t erm effects of continuous biosolid applicat ions on the soil microbial commun ity and soil chemical properties.

At the University of Arizona, liquid Class B biosolids have been applied to land annually for 20 years. His very thorough paper outlined the major findings. Provided c urrent regulatory guidelines are fol lowed, risks to human health from conceivable exposure pathways, even relat ing to chi ld behaviour, have been shown to be very low . Ian 's team also measured bioaerosol emissions from land application in all t he climate zones of the USA, proving that it is not a significant route of transmission .

There was no evidence of long t erm persistence of enteric pathogens in the soil, or migration to groundwater. The soi l microbial community was enhanced, mac ronutrients were increased, metal concentrations were modest, with no increase in salinity, so land -application of Class B biosolids is both safe and sustainable.

Allen Gale outlined the progress made in the Australian National Biosolids Partnership (see box) .

Land Application: Benefits Mike Mclaughlin summarised the resu lts of the extensive National Biosolids Reuse Program (NBRP), a joint CSIRO/Universities project where the benefits of the nutrients N, P, mic ronutrients and soil ameliorat ion have been evaluated. Seventeen research sites in five States, with different soil types and c limates, were treated w ith increasing dose rates of locally available biosolids, and compared with conventional fertil iser practice over a three-year cropping program. At the same time, the effect of metal dosing was investigated. The detailed results are

52 SEPTEMBER 2008 water

Allen J Gale, Chair ABP Advisory Board Formation The Australasian Biosolids Partnership (ABP) is off and runni ng, with the launch of the website www.biosolids.com.au on Monday 28 April 2008 and the appointment of Andrew Speers as Program Manager in July.

The website is divided into two sections: a public area containing information about the membership of the ABP, its Mission and FAQ related to biosolids; and a Members' Pictured left is Ian Pepper (US) and right, Allen Gale section containing Technical (Australia).

Information (legal register; templates for community consultation; case studies; be managed, mitigated or avoided and statistics etc) News and Contacts. the chang ing social and regulatory The Australian Water Association environment can be responded to.

(AWA) is facilitator and administrator for The program is needed because: the ABP, using a subscription model to raise the necessary funds. The key • Improvements in sewage treatment stakeholders are the water utilities in processes are leading to the Australia and New Zealand which production of larger quantities of produce and have to manage biosolids, biosolids practitioners (consultants and • Opportunities to landfill or incinerate contractors), pl us the agencies biosolids are declining. responsible for regulating the management and use of biosolids. ABP • The regulatory environment for the subscribers are from organisations management of biosolids is around Australia and New Zealand. tightening Representatives from su bscribers const itute the 9 person Advisory Board which held its inaugural meeting on 23 July 2008.

What Does the ABP Provide?

The Mission of the AB P is to promote and support the sustainable management of biosolids, with the following objectives: • Support public engagement with respect to the sustainable management of biosolids in Australasia • Support the Australasian water industry on technical and regulatory components of biosolids management • Establish a global network of parties interested in the sustainable management of biosolids The intent of the ABP is to create tools by which the risks identified can

• The cost of biosolids management is increasing • There is a risk that unless good, scientifically-based and unbiased informat ion is presented to commun ities in a clear and collaborative manner, the public may reject land application of biosolids of less than premium grade. This will lead to substantially increased costs for biosolids management and potentially poor relationships with t he communities in which biosolids managers operate. Similar trends have been observed in the North America and Europe.

Interested in Becoming a Member, Want to Know More?

If you are interest ed in biosolids and want to become a subscribing Member, or want to know more about t he ABP contact Andrew Speers at AWA on aspeers@awa.asn.au or (02) 9467-8426.

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biosolids available in a number of reports and papers cited in the full paper, but Mike summarised them by saying that significant yield increases could be attained. Application of biosolids generally provided the equivalent of typical fertiliser application rates by farmers. With high value crops economic returns to the grower were up to $1800/ha from use of one application of biosolids at the NLBAR, with some beneficial effects lasting into the second year. Using current fertiliser costs, the agronomic "fertiliser substitution" val ue for Australian biosolids is estimated to be - $3 million per year (but note that fertiliser prices are currently doubling or triplingi n response to increasing demand, oil prices and supply restraints.

Deborah Pritchard, Water Corporation, measured yields of wheat, canola and oats, comparing the use of lime-amended biosolids with lime plus NPK and with dried anaerobic sludge, for use in their acidic sandy soils.

Th e benefit of LAB, at 10 tonnes/ha, over the three seasons investigated appeared to be from the nutrient value of the recycled nutrients (typically N and P), rather than from the reduction in soil acidity. The application of LAB, however, would save the farmer having to purchase and spread 2 tonnes/ha of lime on acidic paddocks.

A number of speakers commented on the looming world-wide 'Peak P' crisis.

At current rates of use for fertiliser, the known phosphate mines will be exhausted in about 70 years, and more expensive sources may only last another 200 years, so every effort should be made to recycle phosphorus back to food production. Land application of biosolids is the most cost-effective way of doing this and should be celebrated for its contribution to sustainability.

(Note: the amount of 'phosphorus'

water Future Features NOVEMBER - IWCM water cycle, stormwater, groundwater, project del ivery DECEMBER - Agricultural use and reuse, chemicals of concern FEBRUARY 09 - On-site treatment, pressure sewerage, biosolids, international sanitation

54 SEPTEMBER 2008 water

Left to right are Tom Spiers (NZ), Ron McLaren (NZ) and Paul Gibbs (UK).

exported in Australia's grain is substantial).

Another potential benefit of land application of biosolids may be carbon sequestration. Georgina Kelly (NSW DPI) has long been evaluating the use of biosolids and other recycled organics for forestry and rehabilit ation of degraded land. Apart from the economic value of improved growth of plantation timber, and the benefits of recycling N and P, she pointed out that milled timber constitutes a carbon lock-up, even when discarded in landfill. However another major benefit cou ld be the organic carbon sequestered in improved soil, and one of her current projects is to assess how labile, or recalcitrant, such carbon wou ld be.

Rough estimates indicate that, as well as the direct economic value, an off-set of up to $400/year per hectare of improved forest may be claimable if the EMT price for carbon settles at $40/ tonne.

Tim Kempton, of Stance Environmental Pty Ltd, in addressing the wider field of cl imate change mitigation, noted that sludge treatment can produce neutral bioenergy as biogas and the organic carbon in biosolids would be incorporated into soil. His rough estimate was somewhat less than Georgina's but for a carbon price of $40 it would still be of the order of $100/year per hectare of improved farmland.

Land Application: Risks The risks involved in land application comprising pathogens, organics and

heavy metals have long been investigated. The NBRP program has concluded that generally risks from cadmium are overstated but copper and zinc from urban biosolids are still a problem, so that blending is still necessary for general use.

Roger Wrigley et a/ investigated the uptake of cadmium from potting soils blended with biosolids from Melbourne's ETP. Initial concentrations of Cd and Ni were 6.6 and 68.0 mg/kg However, tomatoes, for example, grown on a 1 :3 blend, took up very low concentrations of Cd in the fru it, unlikely to have any health implications for consumers. There was no evidence of poor plant growth. The dark brown colour and good texture were a good sales point.

Brad Clarke reported on t he results of research carried out by the CRCWQT and RMIT on persistent micropollutants, such as dioxins, organoch lorine pesticides and phthalates. Samples of both urban and rural biosolids were analysed from all states. Concentrations were much lower than for European and American samples and generally similar to soils.

They concluded that such compounds posed no risk, and the difficult and expensive analyses for them is not necessary. However more research needs to be undertaken on the risk of polybrominated diphenyl ethers.

Stephen Smith, Imperial College, UK, reported on the potential risk of polyacrylamides used for dewatering biosolids, since the acrylamide monomer

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biosolids is toxic. Manufacturers keep monomer levels very low but even if there is degradation of the polymer in the soil there would be no risks for human consumption due to strong irreversible adsorption to soil and organics.

Pathogens, heavy metals, pharmaceuticals, oestrogens and faecal monitoring of waterways were addressed in other research papers and with some excellent and illustrative poster presentations.

Odour Whatever the undoubted benefits of land application and its popularity with farmers, resistance by the public is

stimulated by odour, which is perceived by the general public to equate to health risks.

Jean Davis, of Sydney Water's Residuals Management Unit, has been assessing a suitable parameter for stability for biosolids from twelve sewage treatment plants (six using aerobic digestion and six using anaerobic digestion). Gaseous samples were extracted , using a hood, and analysed for odour using Odormatâ&#x201E;˘, through dynamic olfactometry, with a panel of human assessors being the sensors. The EPA Guidelines state that stability is achieved at a Volatile Solids Reduction of greater than 38 % but the initial results from this

study suggest that this limit is inadequate for achieving stable biosolids. Based on the results to date for aerobically digested products, a VSR of 65% resulted in a good quality product with acceptable odours and this correlated with pathogen red uction. However, the anaerobically treated biosolids, even with a VSR of 65%, resulted in a poor quality product in terms of odour. A summary of their paper is published in this issue.

Investigations are still continuing.

Michelle Carsen of SEWL reported on a laboratory program scanning odour emissions from various sludges. This was stimulated by the observation that the exhaust fans and raking in their solar dryers extract some twenty times the odour from a static bed.

Samples of different types of st abilised sludge were subjected to low shear dewatering and then stored over a period of time in containers. Headspace odour levels and a suite of both chemical and physical parameters (gas and solid phase) were measured at time intervals.

The peak odour emission rate was observed to be highest for waste activated sludge, followed by aerobicallydigested sludge, then anaerobicallydigested sludge and the lowest odour emission rat e was observed for lagoondigested sludge. Unfortunately no correlations were observed between odour and any of the measured chem ical or physical parameters in the gas or solid phase.

A summary of the paper is also published in this issue.

Mike Thomas in his report (published in Water, August) on the new Maroochydore solar dryer, on the coast of Queensland, said that despite it being open at the sides, and the bed continually raked, they received few complaints from close neighbours except when the stockpile of dried materi al was being loaded into trucks His pragmatic solution: only load in the afternoon when the sea breeze came in.

Odours may repel human beings, but they attract unwanted pests. Ian Dadour, Centre for Forensic Science,The University of Western Australia, investigated what it was that attracted the very nasty 'stable flies' to lay their eggs. He corre lated only w ith ammonia and temperature and ti me, so his answer is to try to reduce ammonia and cover field stockpiles with a semi-permeable fabric such as shadecloth for at least ten days. (The paper is also published in th is issue). In subsequent discussion, Tim

56 SEPTEMBER 2008 water

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biosolids Evans queried whether ammonia itself could be the attractant, or whether it was a useful surrogate for other compounds.

Landi~

Digestion Biosolids production starts with digestion of the primary and waste activated sludge, and numerous methods are employed, as summarised in the review

by Tim Evans.

The choice of method is very much cond itioned by size of plant, location, distance from suitable land applicat ion sites, or other means of d isposal.

Damien Batstone, Paul Darvodelsky and Jurg Keller discussed t hese factors in more detail. With increasing emphasis on effluent quality and application of BNR tech nology, modern sludges have even poorer dewat erability and a decrease in degradability, because of long sludge ages and lower proportion of primary material. This has made anaerobic digestion far less viable as a process, especially in smaller plants, as it is more difficult to maintain the slow growing methanogens, and because less gas is produced, which can make it difficult to heat and mix the digester.

Thus the current default treatment method for biosolids at small-medium scale is aerobic digestion, which produces a product with higher odour potential, and lower overall stability.

Figure 1 gives their assessment of greenhouse emissions for various options.

Production of class B is the most widespread method, necessitating transport of biosolids over 100km away from the urban environment, and consequent increases in cost and greenhouse gas emissions. Consistent stabilisation to grade A would allow local use.Their presentation quoted rough estimates of costs for disposal of a Class B biosolid in $/dry t onne, including transport.

On-site, $10-15; Local land use, $2030; Remote land use, $40-60; Mine site rehabilitation, $40-60; Landfill $10-200.

The fertiliser value is approximately $3/dry tonne.

Large systems (> 150,000 EP) can justify the large capital expenditure to implement advanced anaerobic digestion technologies, including thermal hydrolysis to break down the cellular activated sludge. This is environmentally very beneficial, in terms of greenhouse gas emissions, com pared to the most common approach of aerobic digestion,

58 SEPTEMBER 2008 water

Current Corrbined

Decentraised Aerobic

Centraised Anaerobic

Centralised Therrrel Hydrolysis + Anaerobic

-0.5

0

0.5

1.5

2

2.5

3

kg COD emitted/kg dry blosollds handled

Figure 1. Greenhouse gas emissions for different treatment options (from Batstone et al).

and overall costs are of a similar order of magnitude with benefits to the environment.

The picture is bleaker for small and medium systems, and there are no options that are emissions negative, or neutral. To address this; (a) smaller reactors need to be built at lower prices; (b) smaller scale cogeneration options need to be explored; (c) degradability needs to be improved; and (d) a Class A biosolid should be produced.

Queensland University is doing research to address the last two points, using a new technology that treats the incoming activated sludge at 60°C for a nominal 2 days to enhance degradability and improve final biosolids quality.

Another paper by Paul Darvodelsky, with Kelly O' Halloran, reviewed the options for Gold Coast Water to deal sustainably with 60,000 tonnes per year (up to a projected 150,000 tonnes per year in 2026), either at each of five WWTPs or at a centralised site.

The options ranged from do-nothing, lime-amendment, drying, composting, digestion by aerobic, mesophilic anaerobic, thermophilic anaerobic, to thermal hydrolysis (Cambi). The preferred option on both cost and non-cost bases was for dewatered, un-stabilised biosolids from the other treatment plants to be transported to a central ised Cambi plant and the resu ltant sterile biosolids used on adjacent cane farms. It had 30% less NPV than the do-nothing option but

had a high capex. However, due to t he current re-structuring in Queensland, co upled with the volatile fin ancial market , the Council has resolved to put it on hold .

Tim Kempton, Stance Environmental, outlined the Cambi process at Oxley Creek, where the total energy for the process is supplied by merely 30% of the biogas produced.

5 tonnes of WAS is reduced to 1 tonne of 30% solids which are stable, sterile, non-odorous. Yet currently it is cheaper in Brisbane to dump in landfill than transport to farmers, despite the benefits from N, P and organic carbon.

He discussed t he potential for combining other organic wastes wh ich wou ld generat e even more biogas and usable biosolids. The city of Lillehammer in Norway added household waste, despite problems with plastic and metals, and to put energy in perspective, one person's waste per day could run their car for about 10km.

Drying Sludge drying, either to a st able ca. 5060% solids, or to 90+% solids, where it becomes a sterile free-flowing granular product, has a number of attractions, despite energy co nsiderations.

As noted above, mechanically raked solar driers are being operated in Queensland and Victoria, and Tim Evans had reported on the use of sludge reedbeds for small-medium scale facil ities.

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biosolids Denis Browne, of Flo-Dry, New Zealand, has described their two-stage drier previously in Biosolids Ill. It uses a drum to remove surface 'free' water, then a belt to remove the slower 'chemically bound' water, with no recirculation necessary. However, the preceding mechanical dewatering stage (belt or centrifuge) has been the limiting factor to overall efficiency, and so the company has experimented with an electro-kinetic system. Unlike the belt systems described in Tim Evans' review, the electro-potential is applied in a separat e tank. Laboratory trials succeeded in achieving some 50% dryness in the subsequent belt-press so a 1 t onne/hr pilot rig has just been commissioned and is already showing promise. Because local agricultural reuse is restricted the aim is to provide a fuel. We are promised a report in due course.

C arl Bicknell , of Barwon Water, has to deal with some 1000 tones per week of sludge from ten WWTPs, and constraints on b iosolids management include limited land availability close to the main source of biosolids, proximity to population centres and a high level of community sensitivity.

Barwon Water decided to go ahead with central ised drying. After considering eleven options, they successfully trialled their sludge in a Keppel Seghers pilot plant in Belgium. It consists of a vertical multi-plate raked dryer, with indirect oil heating and a comprehensive odour treatment train, and some dozen or more have been operating in Europe.

For contracting a full-scale plant they decided to employ a public-privatepartnership and Carl Retschko, Project Manager for Plenary Environment, outlined the financial arrangements, which comprise a monthly fixed cost plus $22 per wet to nne, so there is incentive for Barwon Water to optimise their dewatering devices. The average cost will be about $160 per wet tonne, more than twice current costs, but there will be no odour problems and there is potential for beneficial use as fertil iser for broad acre farm ing, soil remediation, organic supplement or fossil fuel replacement.

The design incorporates the necessary redu ndancy to maintain 24/7 operation, with twin dryers and buffer storage. It is estimated that the system will reduce greenhouse emissions by 40 per cent when compared to the earlier practice of st abilisation through long-term lagoon st orage, together with a significant reduction in transportation.

Life Cycle Analysis Most of the above speakers included estimates of greenhouse gas emissions versus energy production by biogas. For example Batstone et al presented a barchart, noting that landfill emissions constituted the worst case, unless the landfill was capped for methane capture, and the CAMBI type process was actually a ' negative emitter' , as previously noted by Tim Kempton.

The AWA Biosolids Taskforce in NSW commissioned Greg Peters at the UNSW to investigate the Life Cycle Analysis of various options, specifying a medium size WWTP of 40,000 ep suitable for regional cities, and providing advice and technical data to his team. The results indicate that the reuse of biosolids products is beneficial, but that the distances between production, processing and reuse locations have a significant impact on the relative merits of options. Energy recovery in a cement kil n considerably improves environmental performance, and (taken as a system) can even result in "negative" carbon emissions overall (a carbon sink). Using a dryer for biosolids at this medium scale, without a digester to provide biogas, significantly worsens environmental performance. A more detailed summary is published separately in this issue.

Final Plenary The keynote speakers were asked for their impressions. Tim Evans noted the increased focus on energy, the importance of not squandering phosphate and the need for consol idation into large plants. Peter Matthews applauded the improvements in technology but insisted that it is the human and business aspects which need attention and he hoped that the next conference wou ld include stakeholders from those areas. St ephen Smith noted the progress since the last conference but lamented the lag in State and Federal regu lations.

Mike Mcl aughlin addressed some areas for R&D: e.g. carbon credits, 'Food Miles' and 'Nutrient Miles" (e.g. import of P from Morocco), so maybe we should aim for extraction of the valuable P before biosolids production. He was impressed at the st andard of presentations by young water professionals, but lamented the habit of the media to trivialise the problem by banal jokes.

The CD of the Proceedings contains the full set of refereed conference papers and is available from AWA Bookshop at a cost of $75. Email bookshop@awa.asn.au

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biosolids

SLUDGE TREATMENT PROCESSES: INNOVATIONS T Evans Abstract This paper critically reviews developments in sludge treatment from the perspective of an experienced and independent biosolids recycling practitioner in Europe and USA.

Land Application I make no apology for recommending land application as the most environ mentally sustainable way to deal with biosolids, since it recycles nutrients, especially valuable phosphorus and organic carbon, to the soil. Other sludge systems do have their place in special circumst ances; they are included below.

Odour. However, representatives from national environmental regulation agencies say that t he cause of more than 95% of complaints about land application of biosolids is odour. Despite this, and plenty of other evidence, ineffective treatment systems are still installed. Malodorants are mainly sulphur and nitrogen compounds. Sulphur compounds are easy to measure by gas ch romatography but experience shows the importance of nitrogen compounds even if the labs had difficulty measuring them. People who only report Scompounds to account for all odour should get out of their laboratories more often . Nobel Prize wi nners Richard Axel and Linda B. Buck discovered that about 1000 of our genes (3%) are coded to the sense of smell, and each is specific for particular odorants; they are expressed differently in different individuals, so a smell can be pleasant to some people yet non-detectable or obnoxious to others and in a minority of cases can produce physiolog ical reactions and symptoms of illness.

Arrays of electronic noses appear to be becoming robust enough for continuous monitoring though the equipment is not inexpensive (www.odot ech.com). The human nose is the most discriminating; a portable olfactometer This is a much reduced version of the paper presented at Biosolids IV, June, 2008 which contains 26 useful references, mostly relating to International conferences.

60 SEPTEMBER 2008 water

Figure 1. The ARSC cover deployed over a large stockpile. (www.nasalranger.com) can be more practicable than bagging samples for an olfactometry panel.

Agricultural application is not unwelcome to most cou ntry dwellers, but if it stinks, those who are upset refer to the internet where there is a mine of misinformation about contaminants and disease, which fuels outrage.

HACCP.The other point I make in this introduction is that contingency planning is vital. We well know that the supply of our raw material cannot be halted, and even a breakdown in a conveyor can result in a stack of raw sludge, which becomes septic very rapidly. Once malodorants have been formed, some of them are intransigent to elimination by subsequent treatment steps.

Agronomy. A fundamental of land application is that the biosolids are being used as part of crop nutrition and therefore the farmer needs adequate advice, given by somebody who understands the agronomy of biosolids.

In the UK biosolids are usually stockpiled on the fields until the spreading season.

Covers are very desirable, both for odour control, prevention of slumping after rain, and safety. I have patented a cover with a 1 m diameter tube along one edge which is inflated by a leafblower, allowing two men t o roll the cover off and on very easily. Water

ballast tubes along the edges anchor it down (Figure 1).

In developed countries, the fear of adventitious contami nants should no longer be a barrier to land application of biosolids. Figure 2 shows how heavy metals and dioxins in UK have been reduced, by source control and hazardous substances legislation.

In April 2008, Severn Trent Water in the UK announced that it wou ld be closing its Coleshill sludge incinerator because, although it met emissions limits, the biosolids were fit for ag riculture now that metals discharging industries in the area had declined .

The Future for biosolids. I think the management guru Peter Drucker summed it up nicely when he said "The best way to predict the future is t o create it", in other words, run a quality assured land application programme that complies with all legal and voluntary req uirements and that is not unwelcome in the community and also publicise the good news of biosolids recycling. I also believe that branding can differentiate good operations from the rest and it can boost morale.

Branding of biosolids can differentiate good operations from the rest.

technical features

biosolids Treatment Processes Dewatering. Dewatering is a vital step in many sludge treatment processes, usually it is a choice between belt filter press (BFP) and centrifuge. Centrifuges use more power than BFP, achieve a few per cent dryer cakes, require little operator attention and are more predictable. "A few per cent dryer cake" might not sound much but one tonne dry solids [1 tDS] at 21 % DS contains 3. 76 t of water, at 24%DS it is 3.17 t; this is a significant difference in the cost of haulage, or any subsequent drying.

Polyelectrolyte is necessary to condition the liquid sludge in order to release water. It is important to get the optimum polyelectrolyte for the particular sludge and to add the optimum amount to get the best cake but this varies with sludge quality, flow rate and solids content. Continuous automatic polyelectrolyte dose optimisation (e.g. www.alfalaval.com/octopus) is currently more practicable for centrifuges than BFP.

100

450

90

400

80

350

70

300

60

250

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50

200

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40

150

30

100

2500

2000

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500

20

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'

'

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Figure 2. Changes in concentrations of potential pollutants in digested sludge from West London: left cadmium and zinc and right, dioxins and furans.

Electro-dewatering: This is an exciting development on the horizon. Ashbrook Simon-Hartley (www.ashbrookcorp.com) has been developing EKG (electrokinetic geosynthetic) belts for new and retrofit BFPs. During the initial development phases, a voltage gradient of 30 volts between the belts produced cake in excess of 40% dry solids; with no voltage gradient the cake was only about 20%DS. Cake from a BFP with EKG will be drier than from an existing BFP or centrifuges and it will not suffer the problems of odour or increased E. coli numbers that are a feature of centrifuges.

Elcotech (www.elcotech.ca) also applies the idea of moving water through cake under an electrical potential gradient in order to achieve greater water removal with their Cinetik electro-dewatering machines. Combustion could even become truly energy yielding.

Liquor treatment: Dewatering liquors can account for 20% of the load of N and P if they are returned to the treatment works . Various high-rate biological treatment processes have been developed to nitrify/denitrify and discharge the nitrogen as a gas. I designed a plant that recovers the phosphate and nitrogen as struvite (magnesium ammonium phosphate) and ammonium sulphate, both of wh ich are valuable fertilisers. Brisbane Water Enviro Alliance (BWEA) has developed struvite crystallisation at Oxley Creek WWTP and it has also been developed by Ostara Nutrient Recovery Technologies Inc. at Edmonton in Canada.

Two significant disadvantages have emerged for centrifuges, both of them resu lting, I think, from the high shear forces experienced by the sludge as it enters the spinning centrifuge bowl. The first applies to sludge that has not been stabilised adequately; centrifuge cake can smell much worse than cake from a BFP. I think that shear disrupts domains of non-stabilised sludge (especially waste activat ed sludge) which then Incineration and other thermal biodegrades and yields malodorants. conversion: If landfill is discouraged, as Charlotte in N. Carolina, USA, had been in the EU, ocean dumping is banned and recycling BFP cake to farmland land application is not possible, successfully for many years, but after combustion is the most [only?] proven they switched to high-solids alternative. Combustion is centrifuges there were so many sometimes portrayed as complaints about odour that energy recovery but this is they switched back to BFP. arguable because sludges The second disadvantage is start out with large initial water that the number of colony contents, w hich means drying forming units of Escherichia it, so that combustion is coli [faecal coliforms] increases sustained, which consumes after centrifuges. The reason is much of the inherent energy. not understood fully, I think the The water in sludge cake shear disrupts clumps of cells, also contributes to the volume which makes more colony of gasses that must be forming units; others think that cleaned before emission and, centrifuging activates colonies since emission cleaning can that were "viable but nonaccount for 50% of the culturable". Whatever the operating cost, it makes reason, there is no real financial sense to minimise the increase in disease amount of water by advanced transmission risk, these are dewatering. after all only indicator In Europe, power stations organisms, but the resu lt can are reluctant to burn dried be non-compliance with Figure 3. Using biogas as road fuel around 1943 - the idea is not sludge because it comes regulations. new but the implementation has improved.

62 SEPTEMBER 2008 water

tech n ica I features

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biosolids under Waste Incineration Directive regulations. Some cement kilns are willing to burn materials such as used tyres and sludge provided it is not detrimental to the quality of the cement.

treatment t o maximise digestibility. In a modern biogas facility in the UK, with CHP and a premium payment for renewable electricity, raw sludge is worth £100/tDS.

Gasification is combustion in restricted oxygen. It might be more publicly acceptable than incineration. It is a technology that works for wood and other materials but, despite well-funded projects, no one has made it com mercially viable for sewage sludge.

This is not to say that gasification of sludge is impossible, just that many have fou nd it very difficult. In March 2008, MaxWest announced that Sanford , Florida will be the first municipality in North America to adopt its gasification system as "an efficient, cost-effective and environmentally friendly way to dispose of biosolids", but all of the gas that it is planned to produce wi ll be used to heat the dryer. It seems to me that direct incineration is much easier.

AD is performed by two families of bacteria: acidogens and methanogens.

Acidogens break down large complex organic molecules into small organic acids. Methanogens convert the organic acids into methane and carbon dioxide Traditionally methanogens and acidogens have been expected to co-exist in single mixed digesters but, actually, they like different conditions. Acidogens work (optimally) at a pH of 5.0 to 5.5 and their growth rate is relatively rapid so they are happy with 1 to 3 days retention whereas methanogens prefer pH 7.5 and grow slowly so they require more than 7 days retention.

Anaerobic digestion. AD has been widely used for sludge for more than 70 years. It is reliable, robust, tolerates variations in sludge charact eristics and toxic shock is infrequent nowadays because of the success of co ntrols on discharges from industry.

Biogas can be used on-site or piped to a more convenient location, for example siting a CHP engine in a village, hospital, industrial area, etc. It has also been used in road vehicles for many years (Figure 3).

The optimum temperatures for AD are mesophilic (35°C) or thermophilic (55°C), abbreviated as MAD and TAnD respectively. MAD is more widespread.

TAnD is quicker and causes greater reduction of enteric pathogens and the digested sludge might be easier to dewater. TAnD used to be thought to be less stable than MAD but apparently this was a perpetuation of faulty research resu lts. AD can achieve 67% volatile solids destruction if there is pre-

Only recently have attempts been made to separate the two functions.

United Utilities in the UK developed pseudo plug -flow acid-phase by using six tanks in series. Plug-flow gives greater reduction in faecal bacteria because there is less short-circuiting .

Thames Water has used a single acidphase tank. Temperature-phased AD has also been used with success. At an existing AD site, one of these enhancedefficiency routes could be achieved by reconfiguring the pipework from digesters operating in parallel to some form of series operation.

Waste activated sludge is difficult to digest because of extra-cellular polymer and cell walls. There has been a growth in disintegration technologies to release hydrolytic enzymes. Ultrasound has had variable results but there are successful installations that have been operating for several years. The design of the ultrasound horn is a factor and it has been found serendipitously that a buffer tank after sonication has the benefit of allowing time for enzymatic hydrolysis to maximise biogas yield in AD.

Figure 4. Waste activated sludge: untreated (left) and after disintegration (right) (courtesy MicroSludge™).

64 SEPTEMBER 2008 water

MicroSludge™ uses a high pressure homogeniser with alkaline hydrolysis and is under active evaluation (www.microsludge.com). Mechanical disintegration does not affect the "pathogen reactivation" phenomenon associated with centrifuge dewatering.

(Figure 4).

Prague WWTP with the Technical University developed mechanical lysis of sludge using hardened knives at the outlet weir of the thickening centrifuge (www.lysatech.com). It can be retrofitted to existing centrifuges. TAnD plus the lysing centrifuge has proved stable.

Compared with MAD, there is less foaming, more biogas and less H2S but more siloxane Lysing centrifuges reduce the viscosity enabling digesters to be fed at 10%DS. Prague dewaters digested sludge in CentriPress centrifuges: the cake is 32%DS, it had low odour and was granular and not sticky.

Cambi thermal hydrolysis was invented in 1995; 13 plants are operating worldwide, including Brisbane, with 7 more under construction/commissioning and more expected in the future (www.cambi.com). Feed sludge (dewatered to about 18%DS) is heated to 160°C (6.5 bar pressure) with steam. Th e combination of pressure-cooking for 30 minutes followed by a flash pressure drop sterilises and disintegrates the feed sludge. Thermal hydrolysis reduces the viscosity of the sludge to the extent that 13%DS hydrolysed sludge is as fluid as conventional sludge at 6%DS, wh ich is roughly the limit for full mixing. It eliminates the "reactivation" phenomenon. Even wast e activated sludge has a high biogas yield following Cambi. The sludge is very easy to dewater; cake in excess of 30%DS from a conventional belt press is typical resu lting in considerable reductions in operating costs. Retrofitting Cambi at a regional works has more than trebled the capacity of the original digesters; it explodes the aerobic biomass, renders it digestible and the performance of the sludge treatment centre exceeds expectations. However, it is only applicable for city-scale plants.

Other feedstocks. Biogas from other organic wastes has considerable potential and Denmark has made this part of its national energy strategy. There are more than 20 centralised biogas plants co-digesting a variety of materials and operating CHP. The sludge is used on farm land to build up soil organic matter and replace mineral fertiliser.

Gate-fees for receiving wastes are based

technical features

biosolids on the biogas yield potential. Bacteria can become acclimated to treating wastes that cou ld otherwise cause toxic shock; as a plant manager said to me, "it is a good thing that the bacteria cannot read the text books." Source-separated and supermarket food wastes invariably contain physical contaminant s, the best answer that I have found is DewasterÂŽ.

Lime stabilisation: Lime is used to treat sludge at many sites. The capital cost of the equipment is low and it is quick to install. It destroys faecal organisms very effectively, but the product from the cheapest systems can be smelly and it is worth spending the extra money on a good quality [ploughshare] mixer to achieve lime-stabilised cake with acceptable odour.

The ADP system (www.rdptech.com) uses lime or another alkaline additive supplemented by electrical heating to achieve the desired temperature, because slaking lime is an expensive source of heat, though it is a good means of raising pH. Done properly with due regard to "welcomed practice" lime stabilisation is very useful. The product is agricultural lime plus nutrients and needs to be sold with appropriate agronomic advice.

Composting: Composting converts the labile carbon fraction, that AD converts to biogas, into CO2 ; it uses energy in the process and volatilises nitrogen as ammonia. Sludge cake needs a carbonaceous bulking agent to balance the C:N and increase the air-porosity.

Compost has much less fertiliser replacement value than digested sludge but it has other benefits and is ideal for soil blending. In Helsinki , Finland gardeners and landscapers buy all of the composted biosolids their 800,000 p.e.

WWTP produces.

The Gore composting system in Moncton, Canada, is impressive (Figure 5). There was no odour, because odours biofilter out before the air passes throug h the covers. Despite 700-800mm rain per year the covers keep the windrows dry and any exposed aeration channels drain surface water off the concrete pad, which has to be heated (compost heat) in their freezing weather.

Drying: Th is is a seductive process, the product is free-flowing and clean to handle. However, thermal drying is expensive; dryers are prone to "thermal events" that if not controlled can result in fire or explosion and drying can reduce agronomic value. One misconception was that because agricultural fertilisers

Figure 5. Gore windrow cover deployment and retrieval machine at Moncton, NB, Canada the cover is tied down to limit windlift when the water ballast tubes have been drained. are granular, granular biosolids would be a direct substitute; th is is a fallacy because biosolids only contain one-tenth the concentration of nutrients and therefore ten times the amount must be handled. However dried biosolids are attractive for particular circumstances such as land application sites far distant from the WWTP or for particular markets such as hobby gardeners, golf courses and amenity uses.

In UK one could truck water 250 km for the amount of energy requi red to evaporate it.

Solar drying: This was practised widely in Europe until the second half of the twentieth century but footprint, labour and unreliable weather caused many to switch to alternatives. Solar drying was revived by the use of "greenhouses" and computerised turners that automate the work of disrupting the crust and maintaining an evaporative surface.

Thermo-System GmbH was founded in 1997 by scientists at the University of Hohenheim (www.thermo-system.com) and now has more than 100 plants worldwide serving populations ranging from 1,000 to 650,000 p.e. Veolia has followed with Soliaâ&#x201E;˘ (www.veoliawaterst.com/ solia/en/) which has 7 plants in France rangi ng from 9,000 to 70,000 p.e. Both systems claim to be able to dry liquid or dewatered sludge and to produce Class-A biosolids with no emission of odours. There are similar plants near Brisbane and Melbourne.

Reedbeds: Reedbed treatment of sludge started in the 1980s and has been gaining acceptance steadily. Engineered

reed beds can be a very effective form of sludge treatment. The beds are sealed; they contain drains set in a bed of aggregate on which reeds are planted.

Sludge is applied to the beds in sequence in shallow layers. I visited Helsinge WWTP, Denmark (20,000 population equivalent) in December 2003 and was very impressed by the absence of odour and the clarity of the treated water. The reeds were brown and appeared dormant but there was no odour and the treated water from the drain was crystal clear.

Conclusions Hazard Analysis Critical Control Point is a very useful tool for designing sludge treatment processes containing as it does the engineering principle of Failure Mode and Effect Analysis. Land application is the most favoured system but a fundamental consideration should be whether the process and product will be welcomed by neighbours and other stakeholders. Phosphate, nitrogen , some pot assium, magnesium, sulphur and trace elements are significant benefits.

Attention to source control of contaminants is essential as is proper treatment, especially avoidance of odour nuisance, and an understanding of the agronomy of biosolids so that reliable advice can be given to farmers.

The Author Tim Evans is the Principal of TIM EVANS ENVIRONMENT, Ashtead, Surrey England, email: tim@timevansenvironment.com, tel: +44 (0) 1372 272 172.

water SEPTEMBER 2008 65

biosolids

ODOUR EMISSIONS FROM SLUDGES: A LABORATORY INVESTIGATION M Carsen, T Anderson Abstract This paper reports a laboratory scale investigation program whereby a range of sludges having undergone different stabil isation processes were subjected to low shear dewatering and then stored over a period of time in open containers.

Headspace odour levels and a suite of both chemical and physical parameters (gas and solid phase) were measured at time intervals. The peak odour emission rate was observed to be highest for waste activated sludge, followed by aerobically-digested sludge, then anaerobically-digested sludge and the lowest odour emission rate was observed for lagoon-digested sludge. However, no correlations w ere observed between odour and any of the measured chemical or physical parameters in the gas or solid phase.

The odour emission rates determined in the laboratory program can be used to estimate solar drier and stockpi le odour emission rates.

Introduction South East Water Limited , a water retailer in Melbourne, owns and operates a number of sewage treatment p lants, all with planned upgrades but little opportunity to increase the area for sludge drying. Consequently two prototype solar driers were constructed and sludges from a number of plants were trialled. Sludge within t he dryers is mechanically raked and air is circulated

This is a much shortened version of the platform presentation at Biosolids IV.

by exhaust fans. It was observed that odour generation was much higher than from a conventional drying pan, and also that em issions from dewatered sludge were higher than from non-dewatered sludge, possibly due to the shear encountered in the dewatering process.

The influence of the method of digestion could not be ascertained in these (expensive) full-scale trials, so, it was decided to conduct a laboratory scale investigation program whereby sludges having undergone different stabilisation processes would be subjected to low shear dewatering and then stored over a period of time in open containers.

Method Appropriate quantities of sludge were sourced from a number of different treatment plants, with a range of sludge stabilisation processes. These included lagoon stabi lisation, aerobic and anaerobic digestion and no stabilisation i.e. waste activated sludge from a conventional secondary treatment plant without any further treatment (refer to Table 1 ). A proportion of these sludges

was dewatered using a household washing machine which operated at an acceleration of around 100 G, rather than the 1000-3000 G of a centrifuge.

Quantities of sludge floccu lated with po lymer were loaded into pillowslips and then spun until no further water was removed , resulting in a cake of around 10% dryness (Figures 1, 2). The dewatered solids (approximately 1OL in each case) were then placed in open

Unfortunately no surrogate for odour could be identified.

Table 2. Parameters monitored.

Gas phase • odour concentration (OU) via dynamic olfactometry; • sulfur gases, including hydrogen sulfide, dimethyl sulfide and methyl mercaptan; • trimethylamine, triethylamine, isopropylamine, ammonia.

Volatile fatty acids (acetic, butyric, and proprionic)

Table 1. Details of sludge samples used in laboratory scale odour investigation program.

• for a limited set of the samples, speciated volatile organic compounds.

Sludge

Description

Solid phase

Lagoon stabilised sludge (2°) from plant A

• total and volatile solids;

2

Lagoon stabilised sludge (2°) from plant A, dewatered in the washing machine

• B0D 5, COD and total organic carbon;

3

Aerobically digested sludge (2°) from plant B, dewatered in the washing machine

• redox potential on water extract;

4 5 6

Aerobically digested sludge (1° & 2°) from plant C, dewatered in full scale centrifuge

• water soluble alkalinity and pH;

Aerobically digested sludge (2°) from plant D, dewatered in the washing machine

• total sulfur compounds;

Anaerobically digested sludge (1 ° & 2°) from plant E, dewatered in the washing machine

• water soluble volatile acids

7

Anaerobically digested sludge (1 ° & 2°) from plant F, dewatered in the washing machine

• specific oxygen uptake rate; and

8

Waste activated sludge (2°) from plant A, dewatered in the washing machine

• nitrogen species.

66 SEPTEMBER 2008 water

technical features

biosolids drums and stored for a number of weeks (as were sludges 1 and 4 referred to in Table 1 which were taken directly from a lagoon and dewatered using a full-scale centrifuge, respectively). At intervals of 35 days, the sludges were agitated by hand, headspace samples were taken using sampling ports in lids fitted only for the purpose of sampling and the parameters list ed in Table 2 were measured in gas and solid phases.

The drums were approximately 500mm high and varied from 270mm at the top and bottom to around 350mm through the middle. These were approximately one third ful l. The sweep air rate for sampling was 5Umin.

Odour hood measurements undertaken within the solar driers themselves, referred to in the discussion, utilised a hood with a sweep air rate of 5Umin over an area of 0. 13m 2 . A comparison of odour emission rates measured using a conventional hood within a solar drier and using the laboratory method ind icated that both methods produce similar estimates of the emission rate.

Th is is expect ed since both techniq ues use a similar area of exposed surface and similar sweep air velocities. For example one sample of aerobic sludge measured 110 and 35 OU.m3/m 2.min (duplicates) using the hood and 130 and 85 using the drum.

Odour emission rates were estimated by d ividing the measured odour concentration by t he area of emission an d multiplying by the vol umetric flowrate of air, i.e. OU.m3/m 2 .min

Results Odour generation rates Lagoon sludge had been subjected to prolonged digestion, and as shown in Figure 2, generated little odour. When subjected to low-shear dewatering, t he odour emissions were still low, below 20 OU.m 3/m 2 .min and stable over the 35 days. However, undigested WAS was odorous and continued reacting t o develop a peak of 160 units at around 1O days.

Anaerobically digested sludge in the first 5-1 0 days, as shown in Figure 3, developed a peak around 20-25 units, tailing off to 5- 10 units.

Aerobically digested sludge, as shown in Figure 4, generated odours that were initially significantly more than those of the other sludges. The sludges dewatered by washi ng machine (i.e.

Sludges 3 and 5) appear to behave similarly with a peak in the range 40 to

180 , - - - - - - - - - - - - - - - - - - - - - - - ~ 160 + - - - - - - . - - - - - - - - - - - - - - - - ; -+- 1 • lagoon

(A)

:E ::::: 140 + - - - - - - 4 - - + - - - - - - - - - - - - - - - < g ·= :::i E; 120 + - - - - - + - - + - - - - - - - - - - - < -- 2 - lagoon Q.

!

(A), washing machine

., ~ 100

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washing machine

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0.,

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5

10

15

20

25

30

40

35

Days after filling of drum

Figure 1. Odour emission rate measured over time in drum experiment for lagoon and waste activated sludge.

180 160

(,)

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:a ::=: zl ·= 140 :::i E; 2. 120

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anaerobic (E), washing machine

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40

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~~ 10

·15

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20

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30

.

35

40

Days after filling of drum

Figure 2. Odour emission rate measured over time in drum experiment for anaerobically digested sludges.

180 160 1 - - - - - - - - - - - - - - - - - - <

(,)

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4 · aerobic (C), centrifuge

~ -~ 140

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., EE

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100

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Figure 3. Odour emission rate measured over time in drum experiment for aerobically digested sludges.

60 OU.m3/m 2.min occurring within 2-3 days and then a reasonably rapid t ailing off to around 5-20 OU.m 3 /m 2 .min. The high shear centrifuged sludge had twice the odour but this also tai led off after about 3 days. (However this particular sludge came from a plant where iron salts (1 0% iron on a dry basis) were used to remove phosphorus, which may have red uced odour by reaction with the sulfur compou nds.) Analysis of other dat a, comparing washing machine dewatering

with dewateri ng via centrifuge for the same sludge source, showed that the latter increased odours by a factor of around ten.

Correlation with gas phase analyses The concentration of several sulfur com pounds (including H2S, mercaptans and dimethyl sulfide), several amines (including t rimethylamine), several volatile acids (including butyric acid), ammonia and toluene was monitored in the gas

water SEPTEMBER 2008 67

biosolids phase. The limits of detection for the substances were low compared with the concentration required to make a significant contribution to the odour level determined by olfactory measurement.

However none of the species were detected with the exception of ammonia and toluene. Thus the observed odour levels were not due to any of these substances with the possible exception of ammonia and toluene. Even in the case of ammonia and toluene there was no observable correlation with measured odour concentrations.

3500

~ 3000

5'

2. 2500 -

..c C 0

I!

2000

-

Q)

g

1500

Correlation with solid phase analyses Volatile solids content is often quoted as being a potential surrogate for odour.

Figure 5 clearly shows that volatile solids content is not a good indicator of odour, as the odour emitted from a sample

-

• 3 4 • 5 • 6 + 7 0 8

. ..

8 ~

1000

.

"C

500

t, 0

50

0

. .... ..

<i .

..

0

40

The present results contrast with the WERF investigation findings which indicate that the concentration of volatile organic sulfur compounds, and dimethyl sulfide in particular, strongly correlates with odour for anaerobically-digested sludges. The explanation for this difference is not apparent.

0

•2

-

~ . . ..+• ;

60

70

80

90

Volatile solids (% of OS)

Figure 4. Odour concentration versus sludge volatile solids concentration measured over time in drum experiment Samples as numbered in Table 1. changes over time whilst volatile solids content essentially does not, and the peak odour emitted by a given sample also does not correlate with volati le solids content.

Volati le acids in the sludge were monitored to assess whether extent of digestion influenced odour. Volati le acid concentrations in sludge of less than

500 mg/L are indicative of normal, wel ldigested sludge (or, in the case of WAS, sludge that has not yet had the opportunity to break down and produce volatile acids). Volatile acid levels in all the digested sludges were less than 500 mg/L, indicating that they were well-stabilised prior to dewatering. In contrast, some of the WAS volatile acid levels were significantly greater than this,

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biosolids indicating that components in this sludge were breaking down during storage and producing significant quantities of volatile acids. There did not, however, appear to be an overall correlation between volatile acid content of the sludge and odour.

It was thought that redox potential, biochemical oxygen demand (BOD), alkalinity or oxygen uptake rate might either give an indication of the type of or potential for further activity in the sludge, but no correlations were observed.

In summary, none of the gas or solid phase parameters that were measured could be correlated with odour.

Ext rapolation to full-scale odour emission rates Solar driers are ventilated with large exhaust fans and they therefore behave as a large odour hood with much greater sweep velocities than are normal in conventional odour hoods. Thus two emission rates can be determined - one based on the odour level at the solar dryer exhaust fan and the other using a normal odour hood placed in the dryer.

A number of measurements were taken comparing emission rates determined by

the two methods. Discarding two suspicious outliers, the ratio ranged from 11 to 30, with an average of 20. Thus the laboratory tech nique multiplied by a factor of 20 could be used to estimate the likely odour emission rate from the solar dryer for a particular sludge having undergone low shear dewatering, which could be utilised as input for odour contour modelling. For stockpiles, the laboratory data could be used direct. In both cases, the influence of shear on odour can also be factored in.

Conclusions

highest for waste activated sludge, followed by aerobically-digested sludge, then anaerobically-digested sludge and the lowest odour emission rate was observed for lagoon-digested sludge. No correlations were observed between odour and any of the measured chemical or physical parameters in the gas or solid phase. Therefore, no surrogate was identified which could be measured in place of the costly and uncertain odour concentration. The odour emission rates measured in the laboratory can be used t o estimate solar dryer odour emission rates by using experimentally-derived factors. For stockpiles, only a correction for dewatering method is requ ired as the measuring method is representative of the environmental conditions under which odour is produced from a stockpile.

A laboratory scale investigation program has been undertaken, whereby sludges having undergone different stabilisation processes have been subjected to low shear dewatering followed by storage in open containers, with gas and solid phase parameters monitored at time intervals.

The Authors

It has been found that the observed odour emission rate, and the variation with time, is dependent on the stabilisation process the sludge has undergone. For example, the peak odour emission rate was observed t o be

Michelle Carse n (michelle.carsen@ sewl.com.au) is a chemical engineer, and is a Technical Projects Officer and Terry Anderson is a Technical Projects Manager at South East Water Limited, Victoria.

~ refereed paper

biosolids

ODOURS FROM BIOSOLIDS THE RELATIONSHIP WITH STABILITY: PHASE II

-

J Davis, J Reynolds, I Miller, S Katupitiya Abstract In 2006 Sydney Water Corporation (Sydney Water) commenced a study to understand the relationship between various stability indicators and biosolids odour. The stability indicators used in this study are Volatile Solids Reduction (VSR), Additional Volati le Solids Reduction (AVSR), Residual Volatile Solids (RVS) in final product, microbial analysis (faecal coliforms and Escherichia coli (E. coli)) versus odour measurements. The preliminary findings of this study were presented at the Biosolids Specialty Ill Conference in 2006 and the investigation is continuing.

To date, twelve sewage treatment plants have been assessed for these parameters, with six using aerobic digestion and six using anaerobic digestion. There has been little correlation found between VSR and odour in all plants. In general, aerobic digestion has performed better in terms of VSR, odour, RVS and pathogen reduction.

Table 1. STP details, digestion and sampling dates.

Discharge Location

Type of Digestion

STP Process

Dewatering Method

Sampling Dates

C

Inland

Aerobic

Biological Nutrient Removal (BNR) with a Tertiary Clarifier

Belt Press

March 2006

D

Inland

Aerobic

BNR

High G Centrifuge

September 2006 (3500 rpm)

E

Inland

Aerobic

BNR with a Tertiary Clarifier

Centrifuge

March 2007

F

Inland

Aerobic

Mixed Waste Activated Sludge (WAS) and primary sludge

High G Centrifuge (2600 rpm)

May 2007

STP

G

Inland

Aerobic/anoxic

BNR

Centrifuge

October 2007

H

Inland

Aerobic

BNR with a Tertiary Clarifier

Belt Press

November 2007

A1

Ocean

Anaerobic

Primary

Centrifuge

Feb-March 2006

B

Ocean

Anaerobic

Primary

High G Centrifuge (2600 rpm)

March 2006

Ocean

Anaerobic

Mixed WAS and primary sludge

High G Centrifuge (2800 rpm)

May 2006

J

Ocean

Anaerobic

Mixed WAS and primary sludge

Centrifuge

September 2006

A2

Ocean

Anaerobic

Primary

Centrifuge

March 2007

K

Inland

Anaerobic

Mixed WAS and primary sludge

Centrifuge

May 2007

Introduction Odour influences the accept ance of biosolids by the comm unity. However, there are many views on the source of odours emitted by biosolids including the chemical composition of influent (generally sulphur based odours), inadequate treatment process, digestion cycle or retention time of solids, polymer addition, dewatering processes, biosolids conveyance processes and storage.

The NSW Environment Protection Authority's (now DECC) 'Environmental Guidelines: Use and Disposal of Biosolids Products' (EPA 1997) specify pathogen and vector attraction reduction requirements, for Stability Grade A, B and C biosolids, however they do not specify odour requirements for biosolids products (Miller et al., 2006). It is commonly assumed that if biosolids have had adequate treatment and meet the stability requirements specified in Guidelines, then the biosolids product should not be odorous. Biosolids that

7 0 SEPTEMBER 2008 water

meet at a minimum the stabilisation Grade B requirement s can be land applied.

The Guidelines specify that at least one pathogen reduction process and at least one vector attraction red uction process must be employed for the respective stabilisation grades (EPA, 1997). Sydney Water uses anaerobic digestion, aerobic digestion, composting and lime stabilisation to meet the pathogen reduction requirements. The other option, air-drying, is not feasible in the urban environment.

The range of vector attraction reduction (VAR) requirements is more extensive. Sydney Water uses the reduction in mass of volatile solids (VSR)

Inconsistency between indicators for both aerobic and anaerobic products.

in the biosolids by a minimum of 38% as its VAR indicator. This method is relatively easy and economical to conduct. However, through experience, Sydney Water has found that Grade B biosolids that meet these st ability criteria may still be odorous. Witherspoon et al.

(2004) also found that dewatered biosolids reaching these criteria could still be odorous.

Another stability indicator for VAR is Additional Volatile Solids Reduction (AVSR) which uses the criteria of anaerobically digested biosolids having no more than 17% further volatile solids reduction when incubated under anaerobic conditions in a bench scale reactor for an additional 40 days at 30370C (AVSR). The criteria for aerobically digested biosolids is having no more than 15% further volati le solids red uction when incubated under aerobic conditions in a bench scale reactor for an additional 30 days at 20°c (AVSR).

technical features

~ refereed paper

At the Biosolids Specialty Ill Conference in 2006, Sydney Water presented the findings of a preliminary study investigat ing the suitability of different stability monitoring indicators.

The volatile solids reduction (VSR) of 38%, and the AVSR of less than 17% for anaerobically digested biosolids and less than 15% for aerobical ly digested biosolids were tested during t his trial.

These two parameters were then compared with resid ual volatile solids (RVS) in the biosolids product (Residual Volatile Solids are the remaining volatile soli d s in final biosolids products), indicator organisms (faecal coliforms and E. coli) and odour measurements to ident ify if t here was a relat ionship between stability measurements and odour. The preliminary results confirmed that biosolids products meeting these VSR requirements cou ld still be odorous.

The preliminary findings were for three sewage treatment plants (STPs). The research presented in this paper, is Phase II of this study including eight more STPs and repeat measurements from an STP in Phase I.

Method Biosolids from eleven STPs (one STP being tested twice) were tested for VSR, AVS R, RVS, indicator organisms (faecal coliforms and E. coli) and odour to understand if there was a relationship between t hese parameters. Table 1 ident ifies the STP, t reatment process, dewatering process and the sampling dates.

Th e temporal influence on different sampling dates for indicators was t hought to be minimal with no rainfall events or major changes to the treatment processes experienced during these sampling periods.

The analysis for VSR, AVSR and indicator organ isms were all undertaken by the NATA accredited Sydney Water laboratories. Either Sydney Water's Odour Measurement Group or the University of New South Wales cond ucted the odour test ing. The same methods were used in this trial as those reported in Miller et al.

(2006) as specified below:

Volatile Solids Reduction (VSR) A series of influent and biosolids samples (m inimum 7) was collected from all STPs over a two-week period for t he VSR measurement. The influent samples were taken post grit and screenings/pre sed imentation. The biosolids sam ples were taken post dewatering. Therefore, the VSR was calculated across t he whole

biosolids Od01r and AVSR-Van Kleeck

40000 ' 37500

AII STPs , - 0.589 p-0.0438

35000 32500 • • • Aerobic • • • Anaerobic

30000

Anaerobic Di ges1ion r-0.842 p-0.0354

27500 25000

~ '8

Aerobic Digestion , - 0.110

22500

p • 0.83 59 Nol Si gni ficant

20000 17500 15000 12500 10000 7500 5000 2500

0

..

•

•

0

• 10

•

20

30

40

AVSR-Van Kleeck

Figure 1. Relationship between odour and AVSR for all STPs. Anaerobic digestion showed a significant positive correlation between AVSR and odour. The combined STPs also showed a relationship between AVSR and odour. t reatment process. The tot al and volati le solids content of t hese samples were determined using Method 2540 G (APHA, 1992). The VSR was calculated using t he Van Kleeck equation (USEPA, 1992). The 'Van Kleeck equation ' is based on a mass balance, assuming constant inert solids.

However, inaccuracies may occur in the VSR calculation, when applied across the whole t reatment process, as it does not account for chemicals and other additives that may be incorporated during the treat ment process (USEPA, 1992).

Additional Volatile Solids Reduction (AVSR) Additional Volatile Solids Reduction (AVSR) was tested for all STPs. at Sydney Water's NATA accredited laboratory (USEPA, 1992).

Indicator Organisms (E.coli and Faecal Coliforms) A composite sample was prepared from t hree or five random grab samples taken from freshly dewatered biosolids at each of t he STPs. The sample was collected, placed in a steri lised container and analysed within 24 hours by Sydney Wat er's NATA accredited laboratory. The faecal coliforms and E.coli counts were determined using t he Most Probable Number (MPN) method (APHA, 1998). A total of 3 com posite samples for each STP were taken during the VSR testing period on different days and submitted for microbial analysis.

Odour Gaseous samples were extracted, using a hood, from biosolids products at all STPs for odour measurement. The extracted sample was analysed for odour using

Odormat™, through dynamic olfactometry, with a panel of human assessors being the sensors, as per the Australian and New Zealand Standards (AS/NZS, 2001). The odour measurements were expressed as odour units (OU).

Data Analysis Correlat ions were undertaken on t he data using Pearson Correlations, first ly compari ng the indicators with odour within the anaerobic treat ments, aerobic treatments and then across all the STPs. The correlat ions were based on t he null hypothesis (HO) that the correlat ion (Rho) is O (Prob > I r I under HO: Rho = 0).

Results The results of the stabi lity indicators measured at all STPs are presented in Table 2. The stability indicators measured were VSR, RVS, odour, indicator organisms and AVSR. The VSR for t he aerobic treatments ranged from 62.3% to 73.9% and were generally higher than for anaerobic t reatments, which ranged from 18.5% to 66.9%. Based on t hese results, all STPs except for A1 (anaerobic treatment) met the VSR indicator limit of 38%. These resu lts were consistent with t he RVS resu lts, where conversely the aerobic treat ments had relatively lower RVS measurements (46.1 % t o 66.6%) than the anaerobic treatments (60.9% to 73.9%).

Generally the biosolids that underwent aerobic treatments produced lower odour (159 OU to 3834 OU) t han the anaerobic treatments (1917 OU to 30,509 OU).

There was no clear difference for indicator organisms between t he aerobic and anaerobic treatments. Aerobic

water SEPTEMBER 2008

71

biosolids treatment had both lower and higher measurements (31,250 MPN/g to 12,403,200 MPN/g) than anaerobic treatment (142,000 MPN/g to 7,745,000 MPN/g) for indicator organisms. Using the US EPA Guideline limit (<2,000,000 MPN/g) for indicator organisms, biosolids produced at one aerobic treatment plant (F) and three anaerobic treatment plants A1 , I and A2 failed to meet the US criteria.

5]

37500

Anaerobic Digest ion r • 0.923 p-0.0086

35000 Dlgeollol,

32500

s

i

•

• • • Aerobic • • • Anaerobic

30000 27500 25000 22500 20000 17500

1 2500 10000 7500 5000

.

•

2500 • 0

•

•

•

0

2000000

4000000

6000000

8000000

There was also a significant correlation between indicator organisms and odour.

The correlation coefficient for E coli was 0.923 with p = 0.0086 and the correlation coefficient for faecal coliforms was 0.924 with p = 0.0085 (Figures 2 and 3).

However, as shown in the Figures, for aerobically treated biosolids, odour did not correlate with any of the other parameters tested.

When data from anaerobic and aerobic STPs are pooled, there was still a significant positive correlation between odour and AVSR with a correlation coefficient of 0.589 and a p value of 0.0438 as shown in Figure 1.

Discussion Stability is a measure of pathogen and vector attraction reduction. It is assumed that if the reduction requirements in the NSW Environmental Guidelines are met, then the biosolids should be stable and not odorous. However, biosolids odour and its impact on neighbours are still extremely difficult to predict.

Odour is very complex and although often attributed t o poor or inadequate digestion, there are many other factors such as quality of the influent, polymer addition, dewatering processes, biosolids conveyance processes and storage that can contribute to odour.

Sydney Water measured VSR, RVS, odour, indicator organisms and AVSR in

72 SEPTEMBER 2008 water

10000000

1 2000000

1 4000000

E. Coll (MPN/g)

Figure 2. Relationship between E coli and odour for all STPs. Anaerobic digestions showed a significant positive correlation between E coli and odour.

Odour and Faecal Collf0nM (MPN/g)

40000 37500

Anaerobically treated biosolids showed a significant positive correlation between AVSR and odour. The correlation coefficient was 0.842 with a p value of 0.0354 as shown in Figure 1.

Aerobic Digestion r • 0.279 p• 0.5920 Not Significt1.nt

15000

Four of the six aerobically treated biosolids passed AVSR (ranging from 2.2% to 26.6%), but all of the anaerobically treated biosolids failed AVSR (range from 18.2 to 32.8%).

A Pearson correlation compared each stability indicator with odour. The correlations were undertaken for anaerobic treatment, aerobic treatment and then across all STPs.

Odour and E. Coll (MPN/g)

40000

e.

refereed paper

Anaerobic Digest ion r • 0.924

35000 ~

32500

p• 0.0085

• • • Aerobic • • • Anaerobic

30000

Aerobic Digestion r • 0.2 76 p=-0.5964 Not Signifi cant

27500

S'

25000

i

20000

8

22500

17500 15000 12500 10000 7500 5000

.

•

2500 •

O

•

• 2000000

4000000

6000000

8000000

t 0000000

1 2000000

1 4000000

Faecal Collfonna (MPN/g)

Figure 3. Relationship between faecal coliforms and odour for all STPs. Anaerobic digestions showed a significant positive correlation between faecal coliforms and odour. biosolids produced at 11 STPs (plus one STP retested). Overall, the results show that there is an inconsistency between the various indicators in predicting the stability of biosolids. One indicator may deem the biosolids product stable, but another indicator may not. This makes it difficult to identity what is the best stability indicator overal l.

Generally, aerobic treatments resulted in a more stable product than anaerobic treatments.

The NSW Environmental Guidelines Grade B pathogen reduction requirements are process based, such as aerobic or anaerobic digestion. There is no specification or quantitative value placed on the treatment processes. All STPs sampled had either aerobic or anaerobic digestion. Using the USEPA and Australian National Guideline limit for indic ator organisms, three of the plants would not meet stability requirements .

There are conflicting views as to whether digestion is a potential contributor to odours in biosolids. While some authors reported that efficient anaerobic digestion and stabilisation of biosolids should result in less odorous biosolids (Foundation for Water Research, 2002; Witherspoon et al., 2004 and Wilkie 2005), it has been reported that incomplete anaerobic digestion could result in odorous biosolids, even more odorous than an undigested product (Envanylo, 1999 and the USEPA, 2000). However, Witherspoon et al.

(2006) reported that more effective digestion or complete digestion of complex organics could still result in odorous biosolids. Based on these findings, it is difficult to identify the true impact of digestion on odour.

In this study, Sydney Water found that indicator organisms and odour were significantly correlated in anaerobically treated biosolids, suggesting that

technical features

~ refereed paper

biosolids

Table 2. Stability indicator results for all STPs. STP

Digestion

VSR (%)

RVS (%)

Odour (OU)

Faecel Coliforms (MPN/g)

> 38%1

N/A1

N/A4

73.9 68.8 66.1 68.5 72.6 62.3

64.5 66.6 63.9 46.1 51.8

159 3,834 2,775 2,890 1,712 1,926

240,000 54,000 1,250,000 12,403,200 32,000

18.5

73.9 60.9 67.4 73.1 63.3 71.1

10,298

4,223,333 560,000 3,376,667 142,000 7,745,000 300,000

E. coli (MPN/g)

AVSR - Van Kleeck (%)

Indicator Limit

C

Aerobic

D E F

G H A1 B I J

A2 K

Anaerobic

61.7 56.1 60.5 66.9 50.8

65.2

1,986 5,411 1,917 30,509 4,784

< 2,000,0003

32,500

< 2,000,000 3

170,000 34,000 1,250,000 12,403,200 32,000 31 ,250 4,223,333 560,000 3,376,667 142,000 7,745,000 272,500

Aerobic < 15%2

Anaerobic < 17%2

15.2 11 .8 10.9 26.6 2.2 19.4 18.2 20.9 21.3 21 .8 32.8 23.4

1. USEPA and NSW EPA guideline limit 2. USEPA and NSW EPA guideline limit 3. USEPA and Australian National Guideline limit (no limit in NSW) 4. N/A - No specification for odour

anaerobic digestion has an impact on pathogen reduction and odour.

is VSR greater than 38%. However, even when a VS R of greater than 50% was

One of the common indicators used in stability assessment in biosolids products

achieved for some biosolids, in this study, the resulting biosolids were still

odorous. This is consistent with the find ings of Witherspoon et al. (2004) that dewatered biosolids achieving a 38% VSR cou ld be odorous.

Australian Company - Global Expertise Protube Ultra Dewatering tubes use state of the art Filament Textile technology for rapid dewatering and consolidation of: • Industrial Sludges • Waste Water • Paper and Pulp Sludges.

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biosolids

[EJ

Another indicator that can be used for vector attraction reduction is AVSR. Additional Volatile Solids Reduction uses the criteria of further VSR not exceeding 17% in anaerobically digested biosolids and 15% in aerobically digested biosolids. The AVSR requirements were not met for two of the aerobic treatments and all of the anaerobic treatments.

Additional Volatile Solids Reduction and odour were significantly correlated across all STPs and strongly correlated with anaerobic treated biosolids.

Based on the results presented in this paper, although VS R is an easy indicator to use, AVSR is the most representative stability indicator of odour for anaerobic treatment. Further investigation is required to determine the most suitable stability indicator for odour in aerobic treatment.

These results are for a small sample set. The sampling of more STPs will continue, increasing the data set and the statistical validity of the results, to verify the correlation between AVSR and odour.

It may also be beneficial to look at STPs individually for each of these parameters, over a longer sampling

period, to identify specific limits for each STP.

Acknowledgments We thank Michael Goh, Sydney Water's Statistician, for conducting the statistical analysis and correlation of these results.

The Authors Jean Davis, Julie Reynolds, Ian Miller

and Sunietha Katupitiya (email sunietha.katupitiya@sydneywater.com.au, are all with the Residuals Management Unit, Sydney Water Corporation, Sydney.

References American Public Health Association (1992).

Standard methods for the examination of water and wastewater. Washington, DC. American Public Health Association (1998).

Standard methods for the examination of water and wastewater. Washington, DC (20th edition).

Australian/New Zealand Standard (2001).

Stationary source emissions - Part 3: Determination of odour concentration by dynamic olfactometry. AS/NZS 4323.3:2001.

Environmental Protection Agency (EPA) (NSW). (1997). Environmental Guidelines: Use and Disposal of Biosolids.

NOBLE Water*

refereed paper

Envanylo, GK (1999). Agricultural Land Application of Biosolids in Virginia: Risks and Concerns. http://www.ext.vt.edu/ pubs/compost/452-304/452-304.html Foundation for Water Research (2005) Sewage Treatment - overview.

Information Note FWR-WFD15.

Miller, I, Katupitiya Sand Davis, J (2006).

Odours within biosolids - the relationship with stability. Australian Water Association Biosolids Specialty Ill Conference. 7-8 June 2006. CD-ROM Conference Proceedings.

Quigley, C, Easter, C, Burrowes, P and Witherspoon, J (2004). Biotechnologybased odour control: design criteria and performance data. Water Science and Technology Vol 50 No 4 pp 319-326.

United States Environmental Protection Agency (1992}. Environmental Regulations and Technology: Control of Pathogens and Vector Attraction in Sewage Sludge.

Washington, DC (EPN625/R-92/ 013).

United States Environmental Protection Agency (2000). Biosolids and Residuals Management Fact Sheet Odor Control in Biosolids Management. Office of Water Washington DC. EPA 832-F00-067.

Wilkie, AC (2005). Anaerobic Digestion: Biology and Benefits. Dairy Manure Management: Treatment, Handling and Community Relations NRAES-176, p63-72.

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technical features

~ ref ere ed paper

biosolids

FLY BREEDING IN BIOSOLID CAKE I R Dadour, S C Voss, N Penney Abstract

levels during temporary stockpiling so that appropriate action such as emergency spreading or the application of insecticides, can be taken in response to excessive fly breeding.

The seasonal pattern of fly breeding in both fresh and aged biosolid cake was established by the exposure of biosolid cake to natural conditions over the course of a year.

Relationships between fly emergence and six factors (weeks exposed, p H, NH 4 , rai nfall, temperature and moisture) suspected of facil itating fly breeding were measured. The aim was to establish a 'best practice' storage procedure for biosolid cake.

Higher ambient temperatures and a Figure 1. Count the flies, every one biting! higher NH4 content of the biosolid cake were associated with increased alternative manure products in fly b reeding. Similarly, the majority of fly agriculture requires the development of breeding in biosolid cake occurred in the guidelines t o limit fly breeding during first 10 weeks of exposure to fly activity. both the transport and st orage of these products.

The Western Australian Water Introduction Corporation produces, transports and Throug hout the agricultural sector, temporarily stockpiles an increasing increased fly numbers represent amount each year of approximately significant economical problems and 55,000 wet tonnes of biosolid cake for health issues, especially in relation to the direct land application as a low-grade stable fly, Stomoxys calcitrans and the fertiliser in broadacre agriculture, forestry house fly, Musca domestica (Greenburg plantations and composting.

1973). Several studies have shown that Once an agricultural site is selected, a hig h stable fly densities c an result in temporary stockpile of biosolid cake is considerable economic losses established. Uncovered stockpiles are throughout rural sectors In the United situated in paddocks where the biosolid States beef cattle industry, stable flies is to be applied. In most cases, cake account for losses of around $400 million application of biosolid cake involves the annually. 'spreading' of between 5 and 10 dry t/ha Excessive fly biting and attempts by over the paddock surface. The biosolid livestock to dislodge feeding stable flies cake is usually incorporated into the can cause fatigue, stress, reduced topsoil withi n 36 hrs of spreading. During grazing intake and weig ht loss. In cattle, mid-summer incorporation of biosolid reduced weig ht gain can result from cake may be delayed if the soil is infestations of as few as 20 stable flies considered too dry, thus preventing t op per animal (Dougherty et al., 1995) soil erosion. Due to the annual nature of (Figure 1). In dairy cattle, heavy farming practices, stockpiles in previous infestations (50 flies per anim al) can years have remained in place for up to reduce weight gain by 25 per cent and eight months, however more recent years milk production by 40-60 per cent has seen the biosolids stockpiled and (Campbell et al. , 2001). St able flies are spread within 7 to 14 days of carting. A vectors of disease-carrying organisms monitoring program has been and, as such, human health risks may established to evaluate fly breeding increase in relation to increased fly numbers (Mramba et al 2007).

The use of animal manures throughout the agricultural and horticultural industries has become a contentious issue due to the high levels of fly breeding associ ated with their use. As a consequence, the use of new or

Fly breeding appears linked to ambient temperature and the NH4 content of biosolid cake.

Where stockpiles of biosolid cake are exposed to environmental conditions, the chemical state of the biosolid cake changes over time. Numerous prelimi nary studies conducted by these authors have shown factors such as the water content, ammonium levels (NH4 ) and pH of the biosolid cake can change considerably when stockpiled in exposed c onditions (Dadour, 2000, 2001 ).

Prior monitoring of stockpiled biosolid cake has indicated that the age of the biosolid cake may influence its attractiveness as a fly breeding resource as demonstrated for cattle manure (Broce & Haas, 1999). In 2000 it appeared that biosolid cake aged more than 6 months no longer facilitate fly breeding but this may be seasonally dependent(Dadour2000).

Understanding the relationship between fly breeding and the changes in the chemical and physical composition of stockpiled biosolid cake over time will be potentially useful in determining how fly breeding can be reduced. This information will aid in the establishment of a 'best practice' storage procedure for biosolid cake.

The main objectives of this study were to (i) identify the factors faci litating fly breeding in stockpiles of biosolid cake , (ii) to assess the seasonality of fly breeding in biosolid cake on t he Central Coastal region of Perth, Western Australia and (iii) to establish the age after which biosolid cake is no longer an attractive resource for fly breeding.

Measured factors include, ambient temperature, NH4 content, rainfall, moisture content, pH levels, and the age of the biosolid cake.

Methods Experimental design Biosolid cake was exposed to climatic conditions and fly activity over the course of one year. In addition, factors

w ater SEPTEMBER 2008 75

biosolids

[ ¡~ refereed paper

suspected of facilitating fly breeding were measured throughout the duration of the study and any relationship observed between fly breeding levels and individual factors was assessed. The fact ors investigated were: weeks exposed , ambient temperature, rainfall, pl us the moisture content, pH and NH4 content of the biosolid cake.

Fresh digested biosolid cake from the Beenyup Wastewater Treatment Plant, with a typical analysis of 20% DS, 50,000 mg/kg total N and 25,000 mg/kg total P and pH 7 was delivered to the Nowergup Biosolids Storage Facility (36km NNW of Perth) every two weeks for a period of 12 months commenci ng on the 8th October 2002. Set up and sampling regimes were conducted every two weeks such that there were a total of 26 sampling periods. At each two week sampling period a series of 60 litre plastic tote boxes measuring 650 x 420 x 280mm were three-quarters filled with biosolid cake. Each tote box was fitted with two 50mm drainage holes. Fine mesh was heat moulded over the holes to allow water drainage but prevent fly larvae moving out of the holes. All equipment was cleaned after each sample date to avoid cross contamination.

On the first sample date (08/10/02), 78 boxes were set up in the above manner (Figure 2). Three of these were immediately removed as controls for the biosolid cake. The remaining 75 boxes were left exposed to natural conditions and fly activity. Fourteen days later (22/10/02) a fresh delivery of biosolid cake was used to set up an additional 75 tote boxes (three fewer than the previous sample). Again, three tote boxes were removed as controls for the biosolid cake. A further three tote boxes from the first sample period were also removed from the site fo r examination of fly breeding and chemical analysis. The remaining boxes were left exposed at the Nowergup site until the next sampling period. This pattern, of setting up fresh biosolid cake in boxes (three fewer than the previous sample period) and removi ng three totes boxes from every sample group, continued every two weeks for a total of 26 sampling periods such that on the fi nal (26t h) sampling date (23/09/03) on ly three new boxes were set up in total. The oldest remaining biosolid cake was exposed for a total of 50 weeks.

Boxes removed at each sampling period were covered with mesh on site (to prevent further fly strike). A subsample of biosolid cake was collected

76 SEPTEMBER 2008 water

Figure 2. 70 litre tubs of biosolids cake

Figure 3. Example of fly emergency and trapping system used during this trial. from each set of three boxes usi ng a small, clean trowel. Th is combined subsample was then sealed in a clean 500ml plastic jar and analysed for moisture content, pH and NH 4 levels.

Following sub-sampling the boxes were watered and set up by covering each box with a fly proof mesh cover (Figure 3). At the apex of t he mesh cover a fly trap was secured at a height of 2 metres. After two weeks, the mesh cover was surrounded with a black plastic bag (punctured with small air-holes to reduce humidity). The function of the black bag was to direct any emerging flies into the fly trap. After six weeks all trapped flies were dead and fol lowing co llection were identified (based on current taxonom ic keys) and count ed. All remaining biosolid cake was subsequently returned to Nowergup and com post ed.

Throughout the duration of the study a weather station located at the Nowergup site recorded hourly precipitation and ambient temperature.

Data analysis Total fortnightly fly emergence and the mean of the six measured factors (weeks

exposed, pH, NH4 , rainfall , temperature and moisture) were calculated. Due to the skewed nature of the fly emergence data set, the data was natural logarithm transformed prior to statistical analysis.

Li near Regression analysis was preformed to assess the relationship between each of the independent factors and fly breeding levels. The linear statistical significance of each of the relationships was evaluated and the percentage of variance accounted for by each factor determined. St epwise Multiple Linear Regression analysis was preformed to determine the mi nimum number of factors required to predict total fly breeding. Spearman's Rank Correlations were computed between all factors measured to assess the linear relationship between fly breeding and each of the independent factors and the interrelationships of t he independent factors to one another. The above analysis was performed on data spanning the entire study duration Significance was determined at the 0.01 level (2-tai led). Analysis was performed using SPSS 12.0 for Windows.

technical features

~

biosolids

refereed paper

Results 600

Fly breeding in biosolid cake Throughout the duration of the study 4 f ly species; house fly (Musca domestica; 3110 flies), stable fly (Stomoxys calcitrans; 2036 flies) , lesser house fly (Fannia canicularis; 143 flies) and false stable fly (M. stabulans; 14 flies) (total of 5304 fl ies) emerged from biosolid cake contai ned within t he box replicates.

When seasonality is considered both M. domestica and S. calcitrans were observed to breed throughout the year w ith a seasonal peak throughout summer (December to February) and a marked decline in breedi ng in wint er (June to August). Sporadic occurrence of F. canicularis within fly traps was noted throughout the year, although numbers were com paratively low. In contrast, M. stabulans were only observed to breed within biosolid cake throughout November and December.

Fly breeding in biosolid cake occurred throughout the year with a sharp decline during w inter (Fig ure 4). The number of emerged flies peaked in summer and o nl y marginally declined during autumn

al e> Q)

500

â&#x20AC;˘ M. domestica Cl S. calcitrans

400

â&#x20AC;˘ F. canicularis

D M. stabulans

E Q) VI

300

Q)

ii:

0

200

a;

.D

E ::,

100

z

0 0

N

"'iB 0w 0 0"' w w

:::

0 01)

0

0

0

N

N

Spring

0

0

0

w w

N

Summer

Autumn

~

N

0 "' 0 "' 0 .... .... ....

0 0 0

N

N

O>

001) 001) 0 0 w w w w

Winter

"'

Sample period

Figure 4. Factors Influencing Annual Fly Breeding.

(March to May) and spring (September to November). Figure 4 also shows t he relationship between f ly breeding and weeks exposed which reflects t he age of the biosolid cake. Regardless of seasonal variation in fly numbers, t he majority of fly breeding occurred withi n t he first 10 weeks of exposure. In summer 99.9% of flies emerged within this 10 week period.

This value was sim ilarly high in spring (99.8%) and autumn (88.0%). In winter, 36.0% of fl ies emerged within the first 10 weeks of exposure. Biosolid cake aged beyond t his 1 0 week period supported low fly breeding(< 1 %).

Stepwise Multiple Linear Regression indicated t hat 3 factors sequentially

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water SEPTEMBER 2008 77

biosolids influenced fly breeding (ambient temperature , NH 4 and the number of weeks exposed to fly activity). The NH4 content of the biosolid cake (R2 = 0.41, F1,76 = 52.39, p <0.01} had the greatest influence on fly breeding throughout the year. A significant positive relationship was also observed between fly breeding and ambient temperature (R2 = 0.31 , Linear Regression F1,76 = 34.05, p<0.01 ).

In all seasons except wi nter, ambient temperature accounted for 31 % of the variation in fly breeding. Further, fly breeding was observed to increase with increasing pH (R 2 = 0.08, F1 ,76 = 7.96, p<0.05) such that 8% of the variation in fly breeding levels was explained by variation in the pH of the biosolid cake.

The Spearman's Rank Correlation Coefficient also supported the SMLR result above but determined a negative relationship between fly breeding and the number of weeks the biosolid cake was exposed to fly activity (R2 = 0.26, F1,76 = 26.63, p<0.01).

Throughout the study, 26% of the variation observed in fly breeding levels was explained by the tot al number of weeks the biosolid cake was exposed.

Fly breeding within the biosolid cake

[SJ declined as the age of the biosolid cake increased. The relationship between the level of fly breeding and the moisture content of the biosolid cake was not significant (R2 = 0.002, F1,76 = 0.16, p>0.05). Similarly, no significant relationship was found between fly breeding levels and rainfall (R2 = 0.05, F1 ,76 = 4.37, p>0.05). Based on the calculated correlation coefficient, rainfall was the least important factor influencing fly breeding within biosolid cake (-0.013, p>0.05).

The resulting model presented by analysis of the data using Stepwise Multiple Linear Regression indicated that the minimum set of factors required to predict fly breeding were NH 4 content and ambient temperature. These factors combined accounted for 51% of the variation observed in fly breeding levels throughout the trial (Stepwise Multiple Linear Regression R2 = 0.51, F1 ,76 = 39.19, p<0.01 ).

Discussion This study determined the seasonality of nuisance fly breeding in biosolid cake in the central coastal region of Western Australia. Four species of flies, Musca

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refereed paper

domestica; Stomoxys calcitrans; Fannia canicu/aris; and M. stabu/ans have previously been associated with manures used in crop production (Paulin et al 1998). Based on the findings of this investigation fly breeding was observed to be most prevalent throug hout the summer months of December th rough February. While not as pronounced, some fly breeding was also observed throughout both autumn and spring.

During the winter months of June through August, fly breeding levels were red uced to negligible levels.

While nuisance fl ies appear act ive throughout three quarters of the year, this activity is predominantly related to ambient temperature. As ambient temperature increases, fly breeding associated with stored biosolid cake also increases. Ambient temperat ure and the NH 4 content of the biosolid cake were the most important factors influencing fly breeding. Given the positive relationship observed between fly breeding and NH 4 content, high concentrations of NH4 appear to increase the attractiveness of biosolid cake as a fly breeding resource.

Under natural conditions, the NH 4 content of biosolid cake decreases over

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~ refereed paper

time. This corresponds to a decrease in fly breeding indicating that biosolid cake is no longer attractive as a resource (Paulin et al 1998). Therefore, reducing the NH4 content during biosolid cake production wou ld contribute to a decline in fly breeding levels within biosolid cake.

Other chem ical factors investigated included pH and moisture content. Whi le there is some evidence to suggest that biosolid cake associated with a slightly acidic pH are less favourable fly breeding resources, the variation observed in pH showed no consistent pattern in regard to the age of the biosolid cake. A similar effect was found with cattle manure with a negative correlation between pH and presence of fly larvae (Broce and Haas 1999).

Similarly, while the moisture content of biosolid cake was observed to decline over time, this pattern was impacted on by the effect of rainfall and season. A significant negative relationship was ob served between rai nfall and fly breeding within fresh biosolid cake.

Thro ughout the duration of this study the moisture content of the biosolid cake dropped to as low as 8%. However, no relationship was observed between fly breeding and the moisture content of the biosolid cake throughout the year. Low moisture content was generally observed once the biosolid cake had aged beyond the f irst 10 weeks. However, following periods of rainfall the moisture content of aged biosolid cake increased to 67% repeated ly without an associated increase in fly breeding. This suggests that aged biosolid cake is not an attractive fly breeding resource regardless of the moisture content. Rather it appears to be linked to the low NH 4 content associated with aged biosolid cake.

biosolids season and temperature variations. The decline in the attractiveness of the biosolid cake as a fly breeding resource appears linked to the associated gradual decline in NH4 content. The exposure of aged biosolid cake to climatic conditions, such as rainfall events, does not appear to facil itate a reinitiation of fly breeding. Furthermore, corresponding increases in moisture content associated with rainfall events do not appear to facilitate increased fly breeding in aged biosolid cake.

Nancy Penney is a Biosolids Strategist with The Water Corporation.

References Broce, A.B. and Haas, M. S. 1999. Relation of cattle manure age to colonization by Stable fly and House Fly (Diptera: Muscidae). J. Kan. Entomol. Soc. 72: 6072.

Dadour, I.A. (2000). Fly breeding in biosolids: Effects of moisture content and

insecticides. Water Corporation, 11 pp.

Dadour, I.A. (2001 }. Stable Fly breeding in biosolids: Cover Effectiveness and Impact of rainfall events. Water Corporation,

Addendum Observations were made in the field on the efficacy of various types of storage.

Stockpiles were bunded by either concrete or wood . When covered by impermeable geomembrane the condensation led to severe ma/odour, but no fly breeding was observed.

However, when covered with shade cloth (170 grams per square metre) a 10 fold reduction in fly strike occurred and a 5 fold reduction even when the cover was open at both ends.

When biosolid cake is stockpiled for ten weeks under cover it can be moved to an uncovered external holding facility with no re-initiation of fly strike.

The Authors Prof Ian R Dadour is a forensic entomologist and Director of the Centre for Forensic Science M420, The University of Western Australia, email: ian.dadour@uwa.edu.au; Sasha C Voss is a PhD student researching in the discipline of Forensic Entomology; and

17pp.

Campbell, J., S. Skoda, D. Berkebile, D. Boxier, G. Thomas, D. Adams, and A. Davis, 2001. Effects of stable flies (Diptera: Muscidae) on weight gains of yearling cattle. J. Econ Entomol 94(3): 780-783.

Dougherty, C., F. Knapp, P. Burrus, D. Willis, and P. Cornelius. 1995. Behavior of grazing cattle exposed to small populations of stable flies (Stomoxys calcitrans L.). Appl. Anim. Behav. Science

42: 231-248.

Greenberg, 8. 1973. Flies and Disease: Biology and Disease Transmission. Vol. 2.

Princeton University Press, Princeton, New Jersey Hill.

Mramba, F., Broce, A.B. and Zurek, L. 2007.

Vector competence of stable flies, Stomoxys calcitrans L. (Diptera: Muscidae), for Enterobacter sakazakii. J. Vector Ecol. 32: 134-139.

Paulin, A., Cook, D., Keals, N., Dadour, I., Ashby, 0. and Peckitt, D. 1998. Stable Fly management project. Report to Minister for Primary Industry, pp66.

'PROVIDING TAILOR MADE ""..-..N GEMEt-'T COLUTIO s¡

Conclusions Over a 1 year study ambient temperature was the primary factor influencing fly breeding in biosolid cake. Secondary to this, fly breeding was further influenced by variation in th e NH4 content of the biosolid cake. The seasonality of fly breeding with in biosolid cake is primarily driven by the ambient temperature and season. Fly breeding was observed for three quarters of the year with a marked decline in the cooler winter months (J une through Sept ember). Aged biosolid cake does not appear to facilitate excessive fly breeding, regardless of

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water SEPTEMBER 2008 79

biosolids

BIOSOLIDS: AN ENVIRONMENTAL LIFE CYCLE ASSESSMENT G M Peters, H V Rowley Abstract

What is LCA?

The goal of this study was to assess the life cycle aspects of alternative treatments and applications for biosolids produced in a typical regional centre in NSW. It aimed to identify the relative environmental sustainability of various applications, compared to the base case of disposal to landfill . The study also highlighted aspects of the process chains that are of great est environmental significance and is intended to assist biosolids managers in decision making.

This paper presents results for total energy consumption, water use, global warming potential and human toxicity potential. Several issues were addressed by a sensitivity check including the distance between facilities and the potential to save water in agriculture.

Life cycle assessment (LCA) is fu ndamentally a form of environmental assessment based on a systemic mass and energy balance. However, it is often confused with other forms of assessment particularly life cycle costing (LCC) which sometimes includes the estimated costs of externalities but requires all matters to be monetised in some way in order to be included. Other environmental assessment tools such as Environmental Risk Assessment, Environmental Impact Assessment, Ecological Footprinting and Carbon Footprinting fi ll important informational roles which are very valuable in their contexts but do not consider environmental matters as broadly or the tech nical system to the same extent to which LCA does as a strategic information tool. Input-Output Analysis shows promise when hybridised with LCA but introd uces the additional data issues associated with joining a technical model with an economic model containing static industry-sector transfer prices. In the case of all these assessment tools, analysts are trying to avoid a reliance on simplistic 'check lists' and purely qualitative debates which can easily be misled by personal bias.

Different aspects of the designs influence different indicators, so the results do not simply suggest one option is superior to all the others in every way.

It is more informative t o consider the key variables.

Introduction The AWA NSW Biosolids Taskforce commissioned the Sustainability Assessment Team at the Centre for Water and Waste Technology (now Water Research Centre), UNSW, to study the environmental implications of the options for biosolids management available for a typical regional town. The Taskforce created eight scenarios and supplied relevant data for a 40,000 equivalent population regional town including: treatment of undigested biosolids by lagoon storage, lime amendment or drying; and treatment of digested biosolids by dewatering and/or drying in a partly biogas-fuelled dryer.

End-uses considered were landfilling, application in agriculture or horticulture, and energy recovery in a cement ki ln.

The aim was to provide strategic environmental assessment for asset managers and planners.

This is a short summary of a verbal presentation to Biosolids IV.

80 SEPTEMBER 2008 water

Life cycle impact assessment (LCIA) is the third phase of LCA according t o ISO 14040 (1997). The purpose of LCIA is to better understand environmental impacts caused by the emissions and environmental int erventions of a product or service. Environmental issues are modelled in the LCIA phase via the calculation of impact category indicat ors. These condense and explain life cycle inventory (LCI) results and reflect the aggregated emission or resources use for each impact category.

Environmental indicators can potentially be calculated and reported anywhere along the cause-effect chain.

Defining an indicator close to an environmental intervention will result in more certain modelling, but will render the indicator less environmentally relevant. For example, reporting carbon

dioxide emissions wi ll be a little more certain than the aggregated global warming potential result, but will only tell part of the overall story. On the other hand, making a statistical estimate of the additional incremental likelihood of coral bleaching as a conseq uence of these emissions will involve complex atmospheric, oceanographic and biological models with many estimated parameters. Thus LCA practitioners almost universally use global warming potential, a so-called 'midpoint indicator', as the impact category for greenhouse gas effects.

There is no consensus set of impact categories for use in LCA (Jensen et al., 1997). Instead, analysts select the categories on the basis of the study's goals and the ki nds of impacts associat ed with the particular system.

The indicators chosen for this LCA were total energy consumption (TEC), water use, global warming potential (GWP), human toxicity potential (HTP), photochemical oxidant formation potential , eutrophication potential, and ecotoxicity potentials for freshwater and terrestrial environments. For brevity, on ly the first four of these eight indicators are reported in thi s presentation summary.

Options for Biosolids Production For th is model the system began with a 60:40 mixture of primary sludge and waste activated sl udge from a WWTP of 40,000 ep. The feasible scenarios for a medium sized facility were defined by the Task Force and are tabulated and ' named' in Table 1 and the assumptions listed in Table 2.

All calculations and bar-charts are based on operation for a nominal day.

The relative environmental sustainability of various applications.

technical features

biosolids Applications of Biosolids

Table 1. Naming the base case and scenarios.

Disposal to landfill In the base case, landfill disposal was initially modelled as taking place 250 km from the WWTP. We assumed that leachate is trapped at the foot of t he landfill and recirculated. Landfill gas (including methane) is released into the atmosphere. There is no benefit from the N and P in the landfilled biosolids.

Application to agricultural land This was initially assumed to take place 250 km from t he WWTP. Nitrogen availability was based on Metcalf & Eddy, 2003; Pritchard, 2005, and EPA, NSW, 2007. Phosphorus bioavai labil ity was assumed to be 70%, consistent with Bengtsson et al. (1997).

Biosolids End Use

Application on land Agriculture Co-composting for horticulture

Landfill

Combustion (cement kiln)

Treatment Processes Undigested, stored in lagoon

Landfill

Digested, dewatered

DigAg

Undigested, lime-amended

LimeAg

Undigested, dewatered, dried Digested, dried with biogas utilisation

DigComp

DryAg

DryKiln

DigDryAg

DigDryKiln

Table 2. Principal assumptions.

Years of life: civil works = 100; mechanical equipment = 8.5 (SWC, 2002) Wastewater generation rate

240 Uperson/day (Boake, 2006)

Influent solids content (TSS)

210 mg/L (Metcalf & Eddy, 2003)

Belt-press product:

2 dt/day at 5% ds. (1.2 PS, 0.8 WAS)

Anaerobic digestion produces

555 m3 biogas per day

Co-composting for horticultural application

Digested sludge

1.4 dt/day

Dewatered sludge (belt press)

23% ds.

Dewatered biosolids would be blended wit h urban greenwaste in a 4:1 greenwaste to biosolids ratio.

Co-comp osting was modelled as an open windrow operation, sited 250 km from the WWTP in t he first model ru n.

Polymer usage

2.5 kg/dt for primary sludge, 7 kg.dt for WAS

Natural gas supplement to biogas:

10,260 MJ/day

Fuel for cement kilns Th is was initially modelled at 250 km from the WWTP with a replacement ratio of 2 t biosolids/t coal (Morton, 2007).

Available energy for undigested and digested biosolids were taken as 18 and 11 MJ/kg (Werther & Ogada, 1999) wit h no measurable difference in the em issions when less than 5% of t he ki ln's energy is supplied this way (Morton, 2007). Thus, for this LCA the principal difference in the emission profiles is the re-emission of biolog ical carbon dioxide instead of fossil-source carbon dioxide.

Life Cycle Impact Assessment Overall results The overall results of the LCIA are presented in Table 3 on a per-functionalunit basis. Scenario DryKiln performs best in three out of these four criteria.

Scenario DryAg performs relatively poorly against al l criteria. Scenario Landfill (the base case) performs well in terms of energy and water consumption but poorly against t he others. The underlying reasons for these variations are discussed below.

A sensitivity check on t ransport distances was performed, assuming 50 km instead of 250 km, the results shown in Table 4. The scenarios most sensit ive to the change in transportation distances were, in decreasing order of sensitivity,

Natural gas used with no digestion

21,850 MJ/day

Dryer product.

96% ds as pellets

Lime amendment after dewatering

250 kg CaO/dt

Table 3. Overall LCIA results (250 km transport distances).

Scenario

Landfill

DigAg

DigComp

994

4029

38

583

GWP (kg COr eJ

2213

HTP [kg DCB-e]

0.2

TEC [MJ]

1

Water Use [L]

LimeAg

DryAg

DryKiln

DigOryAg

DigDryKiln

5010

5408

27467

·2295

16122

3372

687

1228

2065

3006

2065

2963

418

499

525

1837

-490

1072

71

1.6

1.8

1.5

3.0

· 9.1

2.7

· 2.5

Consistent with LCA methodology, these values do not include the combustion of fuel products originating from the process itself, i.e. biogas and biosolids.

Table 4. Results when transport distance is shortened from 250 km to 50 km.

Scenario

Landfill

DigAg

DigComp

LimeAg

TEC

89%

79%

75%

Water Use

100%

82%

78%

GWP

0%

66%

HTP

23%

11 %

DryAg

DryKiln

DigDryAg

DigDryKiln

74%

0%

100%

38%

81 %

60%

32%

0%

32%

1%

63%

62%

14%

100%

42%

79%

10%

12%

0%

100%

3%

46%

Scenarios Li meAg, DigDryKiln, DigAg, DigComp, and Landfill. Scenario LimeAg is most sensitive to transportation distances because of the relatively large mass of t ransportable biosoldis. The presence of Scenario DigDryKiln in this list is surprising given t he relatively small proportion of transport energy, but it is influenced by the avoided prod uction of energy from fuel , w hich significantly reduces its net greenhouse gas emissions.

Total energy consumption As shown in Figure 1, total energy consumption varies sig nificantly across

scenarios. Apart from DryKil n, wh ich is a net energy producer d ue to the value of the dried biosolids , the best performer is the base case , Landfill. Significantly, DryAg is 28 times higher. Interestingly, the difference between DigAg and DigComp is small. In DigDryKiln digestion reduces the offset by diminution of the fuel value of the dried biosolids. The biogas produced by t his process cannot be fully utilised in the scenario due to the intermittent operation of the dryer on this scale (i.e. compression and storage of biogas produced on days when t he dryer is not running is assumed to be uneconomical),

water

SEPTEMBER 2008 81

biosolids so there is a net positive consumption of energy. Nevertheless, when we consider the offsets available in DryKiln and DigDryKiln, in wh ich the biosolids replace an amount of coal that would otherwise be used in cement production, the contrast between them and DryAg and DigDryAg is clear: the extraction of the energy value of biosolids significantly affects the energy balance.

40000

i-;::====================;------------, D Energy (gross calorific value) [MJ]

35000

â&#x20AC;˘ GWP [kg CO2-Equiv.] x10

30000 25000 20000 15000

Global warming potential The main greenhouse gases of relevance to this study are carbon dioxide, methane and nitrous oxide. Figure 1 indicates a correlation between the energy consumption (fossil fuel derived) and the contribution to climate change, with the exception of Landfill due to the emission of landfill gas (mainly methane, 23 times more active than CO2). DryAg and DigDryKiln demonstrate the relative carbon efficiency of natural gas, compared with coal.

Water use As shown in Figure 2, water use generally increases with increasing use of electricity. Most other water use is associated with the provision of construction materials and (in Scenario LimeAg) quicklime. Much of this is offset by the avoided production of nitrogen and phosphorus fertilisers. Those with a kiln requi re more electricity and do not provide an alternative to the production of N and P fertilisers.

The cooling water would be recycled wastewater. The two scenarios drying undigested biosolids need 235 kUday and the two drying digested biosolids need 165 kUday. The consequent

3500 DWater (fresh) [L]

3000 2500 2000 1500 1000 500 0

l>~

'v'li

Figure 2. Water use, per day.

82 SEPTEMBER 2008 water

10000 5000 0

-5000

~ - ~O'

Figure 1. Energy consumption and contribution to climate change, per day.

increase in the treated wastewater temperature is approximately 0.5°C, which is considered negligible.

Human toxicity potential Many processes that contribute to the other impact categories also contribute to this impact category, whether directly or via the embodied electrical energy in materials and process chemicals. Thus most scenarios display much the same positive potential mainly due to the heavy metals and inorganic emissions from the combustion of coal for power. However the scenarios involving the cement ki ln show a net reduction since they reduce the coal com bustion.

Contributing processes The relative contributions to Global Warming are shown in Figure 3. These are electrical energy generation, energy production on-site from fuel (coal, gas or diesel), t ransportation, operating materials (treatment chemicals, fertilisers, etc.) and construction materials (steel, concrete, etc.). The data are shown in these figures such that the absolute values of the components in each scenario add up to 100%.

These results demonstrate the benefits provided by two kinds of offsets available in these scenarios: soil improvement and fossil energy offsets. These benefits are included in this LCA using a technique called system expansion in which the impacts of the alternative means of delivering the additional service are subtracted from the scenario in question.

Add ing biosolids to agricultural soil delivers benefits including increased nitrogen and phosphorus, avoiding the need to add these macronutrients in mineral fertil iser form . The lime cont ent of the material in Scenario LimeAg also stabilises soil pH, but energy use and CO 2 emissions in quicklime production almost completely outweigh the benefits of the avoided agricultural (u nburnt) lime use.

As previously discussed, the delivery of dried biosolids to the cement ki ln in Scenarios DryKiln and DigDryKiln is very important to their overall performance. It offsets the entire GWP in both the 250 and 50 km calcu lations for Scenario DryKiln, and significantly enhances

technical features

biosolids Scenario DigDryKiln such t hat its GWP is the second lowest of all scenarios. Whi le there may be additional financial costs to consider relative to the ot her scenarios , from an LCA perspective the technical option of dried biosolids combustion is very attractive.

Even in the more optimistic 50 km distance iteration, transportation causes up to 60% of the total GWP burden, down from a maximum of 90% for t he original 250 km run. While construction materials are freq uently ignored in some environmental studies, for Scenarios DryAg, DryKiln, DigDryAg and DigDryKiln, construction represents between 5 and 15% of t he t otal GWP for both transport d istance calculations. The significance of transport and const ruction, and the importance of offsets (as discussed in relation t o Scenario LimeAg) illustrate the value of adopting an LCA approac h to the strategic evaluation of environmental performance, rather t han the simpler option of just evaluating onsite energy and fuel consu mption.

Conclusions The results of this LCA suggest that very large differences in enviro nmental performance can result from the selection of different technologies.

The base-case (Scenario Landfill) uses little energy and water but otherwise performs poorly. In general, the reuse of biosolids products is to be encouraged , b ut t he distances between production facil ities, additional processing and ultim ate reuse locations have a significant impact on the relative merits of biosoli ds management strateg ies, and efforts to minimise these will have a signif icant impact on the performance of reuse schemes. Energy recovery in a cement kiln considerably improves environmental performance, and (taken as a system) can even result in an overall offset of carbon. Using a dryer for bio solids at this scale, w ithout a digest er (scenario DryAg) to provide biogas, sig n ificantly worsens environmental

Contributing processes 100% 80% +..--.r---i1----r,-60% 40%

-80%

~ operating materials â&#x20AC;˘ oonstruction materials

Figure 3. Relative contribution of processes to GWP in 250 km scenarios.

performance in most indicator categories.

Further water savings may be achieved by agricultural biosol ids application due to increased plant-available soi l moisture via improvements to soil st ructure.

Adopting further detailed assumptions we may also illustrate t he relative significance of soil carbon seq uestration.

We hope to publish an analysis of these possibilities soon.

Acknowledgments Funding for t his study was provided by t he NSW AWA Biosolids Taskforce.

Boake, M. (2006) Technical Director, Veolia Water (pers. comm., 060714, Peters, G.).

EPA, NSW. (1997) Environmental Guidelines: Use and Disposal of Biosolids Products,

NSW Environment Protection Authority, Chatswood, NSW. ISO (1997) ISO 14040:1997 Environmental management- Life cycle assessment Principles and framework, Geneva,

Switzerland.

Jensen, A. A., Hoffman, L., M0ller, B. T., Schmidt, A. , Christiansen, K. , Elkington, J. and van Dijk, F. (1997) Life Cycle Assessment (LCA): A guide to approaches, experiences and information sources, Report to the Environmental

Agency, Copenhagen, Denmark.

Metcalf & Eddy (2003) Wastewater

The Authors Dr Greg Peters is Program Manager Sustainability Assessment at the Centre for Water Research and Hazel Rowley is a PhD candidate, bot h in t he School of Civil and Environmental Engineering at UNSW, email g.peters@unsw.ed u.au.

Engineering: Treatment and Reuse (4th

Edition), McGraw-Hill.

Morton, E. (2007) Manager Alternative Fuels, Lehigh Cement Company (pers. comm., 070207 , Peters, G.).

Pritchard, D. (2005) Phosphorus bioavailability from land-applied biosolids in south-western Australia, Thesis (PhD

thesis), Curtin University of Technology.

References Bengtsson, M., Lundin, M. and Molander, S. (1997) Life cycle assessment of wastewater systems, Chalmers Institute of

Technology, Goeteborg, Sweden.

SWC (2002) Sydney Water Annual Report 2002, Sydney Water Corporation, Sydney.

Werther, J. and Ogada, T. (1999) 'Sewage sludge combustion', Progress in Energy and Combustion Science, 25, 55-116.

water

SEPTEMBER 2008 83

asset management

Q

refereed paper

SUSTAINABILITY-BASED ASSET MANAGEMENT IN THE WATER SECTOR DR Marlow Abstract Research is currently being undertaken into the role sustainability principles should play in asset management, specifically within the urban water sector.

The overall aim of the research is to help water sector professionals to 'operationalise' sustai nability objectives at the asset management functional level, and provide tools and approaches for decision support. As part of this research, structured int erviews have been undertaken with a range of industry professionals who provided insight into current industry practices and opinions on where there remain research gaps. As well as outlining the conceptual relationship between asset management and sustainability principles, this paper presents summary results from these interviews.

Introduction Historically, the wat er sector has developed out of the need for public health and environmental improvements [1], and has increasingly had to operate in a financially efficient manner (2). The water sector is thus intrinsically engaged with achieving financial, social and environmental outputs, which need to be sustained over the long term (3). Given the asset-intensive nature of the sector, asset management should be a key vehicle for delivering sustainability goals of a water authority (4). From an asset management perspective, however, sustainability goals can simply be an expression of the intent to provide broadly affordable levels of service into the future [5, 6). Notwithstanding the importance of achieving sustainable service provision, sustainability is increasingly being interpreted in line with the co ncept of 'sustainable development' [7]. With this later context in mind, achieving sustainable out comes through

A full report detailing the interview responses and more detailed findings from the research will be available from the author in October 2008.

84 SEPTEMBER 2008 water

effective asset management is a relatively new chal lenge facing water authorities.

The National Research Flagship "Water for a Healthy Country" is currently undertaking research into the role sustainability principles should play in asset management, specifically within the urban water sector.

The Meaning of 'Sustainability' The dictionary definition of sustainability (e.g. from Chambers Concise Dictionary) indicates that the word arises from the verb "to sustain". At a basic level, 'sustainability' thus merely implies the ability to continue to do something indefinitely. As intimated earlier, in an asset management context, the term sustainability could therefore be simply an expression of the need to continue to deliver water services into the future. This type of sustainability is, however, not the focus of this paper. Instead, the definition of sustainability being discussed herein is that which is synonymous with the concept of 'sustainable development', a widely accepted definition of which is given in the Brundtland Report [7) as: "Development that meets the needs of the present without compromising the ability of future generations to meet their own needs."

Sustainability in the w ater sector As noted previously, there is an inherent focus on financial, social and environmental outputs in the water sector, the so called 'triple bottom line' of business performance (in contrast to the trad itional 'single bottom line' of financial performance alone) (8). Having a focus on the triple bottom line, however, does not mean that the wat er (or any other) sector is operating in a sustainable manner; a triple bottom line focus is a necessary but not solely sufficient component of sustainability.

ASCE/UNESCO [9) previously defined a sustainable water system as: ... one that is designed and managed to contribute fully to objectives of society, now and in the future, while maintaining

ecological, environmental and hydrological integrity.

In the author's opinion, it seems reasonable to assert that given emerging mega-trends (i.e. widespread trends of global or regional impact), the sustainability goals of the water sector must also address wider societal issues such as climate change, population growth, changes in technology, skills and knowledge gaps associated with an ageing workforce, changes in demographics, and the ethics of wateraccess rights.

Within Australia, water issues are currently high on the national agenda due to a long period of drought in much of the country. In fact, water security is one of the biggest environmental challenges facing Australia, especially with projected levels of population growth [1 OJ. Notwithstanding the utmost importance of water scarcity issues, the capitalintensive nature of the water sector requires that water authorities manage their physical assets effectively (11 ).

Furthermore, the asset stocks used to treat and transport water and wastewater have a direct influence on the way in which water is extracted and returned to the environment, the service provided to communities now and into the future (6), and thus whether or not a water system is sustainable in the context of t he ASCE/UNESCO definition given above.

Hence, it is necessary to consider sustainable water systems not just in terms of water resources, but also from the perspective of asset management.

Asset Management The term 'asset management' in itself remai ns ill-defined and numerous definitions are in use [12). The following definition, modified from that given in the International Infrastructure Management Manual (13], is considered by the author

Integration of sustainability principles into asset management.

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to encapsulate the main features of this emerging d iscipl ine: "The combination of management, financial, economic, engineering and other practices applied to physical assets with the objective of providing the required levels of service to customers and the environment at acceptable levels of risk and in the most eff icient manner. " In practice, however, the focus of asset management effort can vary significant ly depending on where an individual organisation is in t he 'asset management' journey. For example, in recent research into condition and performance assessment protocols (14). it was suggested b y t he authors that a succession of dominant philosophies has underpinned the strateg ic asset management strategies applied to existin g assets in the water sectors of count ries such as the UK, Aust ralia, and increasingly the USA, namely:

asset management Table 1. Role of interviewees.

Role of interviewee

Number of interviews

Senior managers (CEO, general managers)

4

Mid-level manager (asset management)

7

Mid-level manager (sustainability)

5

development, a series of interviews were undertaken w ith water sector professionals from various water authorities and other stakeholder organisations. The design and delivery of the interviews, as well as the summary fi ndings, are discussed in the remainder of this paper.

Other asset management role

2

Other sustainability role

3

Interview design

Other stakeholders

4

Given the aims of the interviews were to elicit viewpoi nts on relatively specific issues, a structured format was considered appropriate. A questionnaire was therefore developed for use in the interviews and a standardised interview protocol adopted. Five water authorities located in three states (Victoria, New South Wales and Western Australia) took part in the interviews; t he roles of the individuals who participated in t he interviews are summarised in Table 1.

Auxi liary interviews were also undertaken wit h other stakeholders to provide additional perspectives on issues under discussion. As shown in Table 1, 25 interviews were undertaken, each taking about one hour to complete.

• Condition-based asset management; focused on maintaining 'what assets are' (the cond ition the assets are in).

• Performance-based asset management; focused on 'what assets do ' in a local sense; that is, t he quest ion is posed, is the asset doing the job that it was intended to? If not , maintenance and/or capital invest ment are required .

• Service-based (service level driven) asset management; w here performance is no longer viewed in terms of local considerations (the design intent of individual assets), but instead is assessed in terms of the delivery of service and independently of the co ndition or performance of a specific asset relative to its design intent.

• Risk-based asset management; which seeks to achieve optimum life cycle management of assets through consideration of risk to service

provision. The condition and performance of an asset are simply factors in t he assessment of risk.

Each successive development has built upon the previous approaches by retaining the best practices developed to t hat point, but using them differently, and with a different emphasis. Through this process, 'best practice' strategic asset management frameworks have evolved over time so as to shift the focus away from a purely asset-centric view, to one that considers explicitly the underlying purpose of owning and maintaining t he asset portfolio; the provision of service at an acceptable level of risk.

In a similar vei n, and assum ing a growing commitment to sustainability (in line with the concept of sustainable development, as defined above), t he next logical development is to focus on sustainability principles, and to fully develop sustainability-based asset management frameworks that deliver outcomes that are fully aligned with the concept of sustainable development across the asset life cycle [4].

Asset Management within the Australian Water Sector To help understand where the Australian water sector is with respect to the development of its st rategic asset management philosophies and frameworks, and thereby identify t he need for further research and

It is important to note that in selecting water authorities to participate in t he research , no attempt was made to be representative of the Australian water sector overall. In fact, authorities were approached who were considered (by the researcher) to be actively engaged in a sustainability journey, as well as undertaking relatively advanced approaches to asset management.

Furthermore, si nce individuals volunteered to participate in the interviews, it can be anticipated that they represent a self-selecting sample of people actively engaged with (or at least having an active interest in) t he sustainabi lity challenge. While this selection procedure does not allow a representat ive view of the Australian sector to be elicited, the approach was justified because the overall aim was to

Table 2. Questions relating to the understanding of asset management and sustainability.

Question posed

Common themes in answers

What does the term 'asset management' mean to you?

Answers were generally couched in terms of whole of life concepts, with a focus on service and risk.

In practical terms, is 'asset management' within your organisation primarily concerned with aging assets?

In general, no... ageing assets are only part of the story, as asset management has a wider whole of life focus.

What does the term 'sustainability' mean to you?

Sustainability was generally considered in terms of 'sustainable development', with strong business themes and a triple bottom line focus being expressed as well.

Does your organisation have a formal commitment to sustainability as a core business concept?

If so, how is this expressed?

There was significant high-level commitment to sustainability as a core business concept, expressed in terms of corporate goals and objectives, as well as planning frameworks.

From the perspective of the water sector, where do you think the key links between asset management and sustainability are or should be?

Sustainability and asset management were seen to be considerably interlinked, with elements of sustainability occurring in each part of the asset life cycle, but especially at the strategic planning level.

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asset management Table 3. Questions relating to the understanding of asset management and sustainability.

Question posed

Common themes in answers

In your opinion, are the requirements of sustainability-related written policies and procedures embedded in day-to-day practices across your organisation and supply chain?

Are they effective?

How is the sustainability of asset management measured and reported in your organisation, and do the approaches used drive sustainability effectively?

What techniques does your organisation apply to the quest for more sustainable solutions to the asset life cycle?

From your view of asset management within the water sector, what have we already got right from a sustainability perspective and what are the remaining challenges?

In general, high-level commitment was not considered to be embedded in day-to-day practices, so policies and procedures are not as effective as they could be. There was generally less opinion expressed on the sustainability credentials of the supply chain.

High-level triple bottom line measures were generally discussed, along with post implementation studies of capital schemes. Non-financial asset management KPls like spills, bursts and blockages were seen by some as relating to sustainability.

Strategic planning frameworks, advanced risk analysis, advanced cost-benefit analysis, multicriteria decision making tools, life cycle assessment and whole of life costing were mentioned.

What the sector has got right: a history of delivering good social and environmental outcomes aligned with the needs of society. The challenge is that the world is changing rapidly and the solutions for yesterday's problems may not be suitable to meet emerging challenges such as climate change, changing demographics, and a carbon constrained future.

From your view of asset management within the water sector, Information, appropriate tools and knowledge were seen as some of the key barriers, as were the what do you consider are the most significant barriers to willingness to pay for sustainability, especially where the outcomes are less tangible to customers. advancing sustainability?

Overall, regulation is seen to aid delivery of outcomes where the regulation is focused on these Does current regulation of the sector promote or hinder outcomes. However, most held that regulation is focused too narrowly to allow sustainability to be the attainment of sustainability goals? achieved in some schemes, and that regulation can stifle innovation.

determine the research needs for developing sustainability-based asset management.

Results Table 2 and 3 summarise the most common responses given to interview questions. As can be seen from Table 2, a sophisticated definition of asset management (in line with the definition given previously) was generally stated. In particular, asset management was not considered to be associated with ageing assets, but was instead concerned with a life cycle focus. The definition of sustainability expressed was generally in line with the concepts of 'sustainable development' discussed above, along with strong business themes and a triple bottom line focus. The opinions expressed also indicated that participating water authorities have a high level of commitment to sustainability, and are investing in various initiatives to raise awareness of sustainability issues and to embed new modes of thinking into decision-making.

Another reoccurring theme expressed in the interviews was that there are strong links between asset management and sustainability in the water sector, and thus a strong expectation that asset management will play a significant role in achieving sustainability-related outcomes. Besides the direct impact of more efficient use of funds and resources through effective asset management, this seemed to be related to the opinion that physical water service assets, and the ability of these assets to meet society's needs in the future, form part of the legacy we leave future generations.

86 SEPTEMBER 2008 water

As shown in Table 3, despite the high level of commitment to sustainability expressed, the general feeling was that sustainability is not yet embedded in the day-to-day practices of the water authorities. While much effort has been expended to develop policies and raise awareness, there was a general opinion that sustainability is still a 'bolt on' consideration in many business processes and/or decisions (i.e. not fully integrated into practice), and that legacy drivers like financial efficiency and regulated outcomes are often still overriding considerations.

Information obtained indicated that a range of tools and approaches are currently been used in the quest for more sustainable solutions (as listed in Table 3), but overall there was a desire for more quantitative approaches that remove subjectivity where possible (though the approaches also need to be pragmatic in application). In terms of asset management practices, the participating water authorities all appear to be expending most effort to integrate sustainability principles into the early stages of the asset management cycle (especially strategic planning approaches). This focus can be explained from a number of perspectives; including the quite reasonable expectation that the 'sustainability envelope' for a system is set at this stage (i.e. systems can be operated in a less sustainable manner than set at the planning stage, but it is difficult to operate them in a more sustainable way).

Overall, the later stages of the asset management cycle (operations,

maintenance, renewals, and disposal) do not yet appear to have been re-examined in the light of sustainability principles. In fact, some interviewees expressed the opinion that the concept of sustainability does not need to cascade further down than high-level strategy plans. The inference being that addressing sustainability concepts at the strategic planning phase embeds sustainability into the resultant schemes, and thus allows the detailed planning phase to focus just on asset management considerations (e.g. reliability and robustness of assets). In contrast, others expressed the opinion that, while the design stage does indeed set the achievable envelope for sustainability, existing assets still represent a large portion of the asset stock. As such, there is a need to re-exam ine sustainability aspects of these assets to determine if there are opportunities to make incremental changes that will provide large benefits across existing asset portfolios. One such action suggested was to consider reconfiguring water distribution networks from a sustainability perspective, because current zonings are often still reflective of legacy issues (such as operational ease when district office managers had responsibility for parts of the network before corporatisation).

Perhaps, as would be expected, the interviewees considered that the water sector has a history of delivering good social and environmental outcomes aligned with the needs of society. This achievement was considered to reflect the appropriateness of asset management and other policies and practices to date. The upcoming

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challenge is that the solutions applied to yesterday's problems are not expected to meet emerging challenges such as cl imate change, changing demographics, and a carbon constrained future. The need for pragmatic sustainability-based tools (and/or ways to use these tools), and the need to fully embed sustainability principles into all business and asset management processes (rather than treati ng them as a bolt-on consideration) were also seen as significant challenges to be addressed.

Lack of information, appropriate tools and broader systems knowledge were seen as some of the key barriers to achieving a more sustainable sector, as were the willingness to pay for sustainability, especially where the outputs of investment are less tangible to customers and other stakeholders. In a broader context, institutional and personal inertia with respect to the need for change were also considered to present barriers to achieving sustainability outcomes, as were regulation and wider governance issues withi n the sector. Some interviewees also noted that urban planning is a key factor in driving change in the water industry and better links with developers and urban planners must be developed. Furthermore, it was noted by some that the link between water, wastewater, solid waste and energy must also be explicitly considered if we are to make the wat er sector more sustainable.

A number of interviewees expressed strong opinions that regulation is a barrier to the innovation needed to meet sustainability goals, although there was a general acceptance that where there is a regulatory need, it is relatively easier to obt ain funding for capital investment in solutions to meet t hat need. The direct corollary of th is, however, is that solutions that are considered/shown to be more sustainable are more difficult to get approved where there is no regu latory requirement, or where there is conflict between wider sustainability outcomes and an existing regu lation.

As noted in Table 3, a common theme expressed was that regulation is focused too narrowly to allow sustainability to be achieved in some schemes. An example quoted a number of times was the requ irement for zero discharge to some creeks, which severely limited the options that could be considered, and ultimately drove the selection of less sustainable solutions. Another example given was the regulatory drive to spend money on upgrading sewage treatment plants, when a different use of the money (e.g. investment in stormwater discharges) would deliver a better return on investment when judged in t erms of wider output measures and outcomes.

Conclusions The interviews undertaken as part of this research have indicated that t he participating water authorities have made a strong commitment to sustainability, and this is being expressed in a range of initiatives intended to deliver benefits across the triple bottom line. The interviews also indicated that, within the participating water authorities, a significant focus is currently being given to the integration of sustainability principles into strategic planning. The impact of this effort on overall sustainability outcomes will depend on how much growth is occurring (e.g. the relative investment in new assets com pared to the modern equivalent value of existing assets), as well as the inherent sustainability of that growth. Th is later aspect must be considered within the wider context of urban development, transport policy, environmental factors associated with the water cycle, and

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water SEPTEMBER 2008 87

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asset management social aspects, including those related to the equitability of water service provision.

Add ressing assets in t he middle of t heir life cycle still remains a challenge, and less emphasis is currently being given to this aspect of sustainability.

It is interest ing to note (t hough perhaps not surprising) that the majority of opinions relating to sustainability were expressed solely w ith respect to sustainability of the wat er sector. In on ly a smal l minority of cases was the opinion expressed that sustainabi lity is a broader societal issue in w hich the water sector plays only a minor (though still important) part. From the author's perspective, it seems that 'sustainable development' requires a holist ic societal view to be taken, consideri ng factors related to the wider economy and human activity, including patterns of consumption, popu lation growth, modes of urban development and overall attitude t o the ecosphere.

With this in mind and from the perspective of the research design, reducing sustainability issues to a component of society (i.e. individual sectors like the urban water sect or) can be criticised; reducing issues to focus on one aspect of t his sector (asset management within the urban wat er sector) even more so. However, in many respects, sustai nability is an emergent property that depends on the cum ulat ive impact of individual actions/initiatives on society and ou r collective mindset, so t his approach is defensible, especially

given the aims of this research were to inform specific future research activities.

Furthermore, it seems appropriate to the author that the water sector should be an initial focus of efforts to move society to a more sust ainable basis, because access to appropriat e water services is a fundamental human right that crosses intergenerational boundaries, and is intri nsically concerned with triple bottom line outcomes.

Acknowledgments The author expresses his deep appreciation to all organisations and individuals w ho participated in t he interviews and research. The fi nancial support of the National Research Flagship 'Water for a Healthy Country' is also gratefully acknowledged, as is t he review of the paper by Steve Cook and Magnus Moglia.

The Author David R Marlow is an engineer with a background in consultancy and research related to asset management in th e water sectors of the UK, Australia and the USA, and gained a PhD in modelling of environmental impacts from Heriot Watt University, Edinburgh. He can be contact ed at CSIRO Land & Water, 34 Graham Road, Highett, Victoria, Australia, email david.marlow@csiro.au

refereed paper

Geography and Environmental Science and the Facility for Advanced Biofiltration, Monash University.

2. Burn, S., Marlow, D. Moglia, M. & Buckland, P. (2007) Asset management for water infrastructure, Water Asset Management International, 2.3, 12-18.

3. Kenway, S., Howe, C. & Maheepala, S. (2006) Triple bottom line reporting of sustainable water utility performance,

AwwaRF Report 91179, AwwaRF, CO, USA. 4. Marlow, D. (2006) Sustainability based asset management, Proceedings of ENVIRO 06, Conference and Exhibition on "Building Sustainable Cities", May 2006,

Melbourne, paper e6190.

5. Gohier, L. (2005) Canada's lnfraguide: bringing the best of research and practice together for sustainable asset management, Water Asset Management International, 1.3, Sep., 14-15.

6. Allbee, S. (2005) America's pathway to sustainable water and wastewater systems, Water Asset Management International, 1:1 , 9-14.

7. WCED: World Commission on Environ ment and Development (1987) Our Common Future (The Brundtland Report),

Oxford: Oxford University Press.

8. Elkington, J. (1998) Cannibals with forks: the triple bottom line of 2 1st century business. Gabriela Island, BC: New

Society Publishers. ISBN 0-86571 -392-8.

9. ASCE/UNESCO (1998) Sustainability criteria for water resource systems,

References

Prepared by the Task Committee on Sustainability Criteria, Water Resources Planning and Management Division, ASCE, USA.

1. Brown R. & Clarke J. (2007) Transition to water sensitive urban design, the story of Melbourne, Australia, School of

10. Nowak, R. (2007) Australia - the continent that ran dry, New Scientist magazine, issue 2608, 13 June 2007, 8-1 1.

11. Foley, A. (2005) Benchmarking asset management, Water Asset Management International, 1:1 , 22-25.

12. Causey, P.H. (2005) A national asset management steering council: the time has come, Water Asset Management International, 1:3, 10-13.

13. IPWEA (2006) International infrastructure management manual, Australia/NZ Edition.

14. Marlow, D, Heart, S, Burn, S, Urquhart, A, Gould, S, Anderson, M, Cook, S, Ambrose, M, Madin, B, & Fitzgerald, A (2007) Condition

ÂŽ

'A' class water or basic treatment¡ EPCO has the solution

88 SEPTEMBER 2008 water

a

assessment strategies and protocols for water and wastewater utility assets, WERF

Report 03-CTS-20CO.

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asset management

REMOTE DIAGNOSIS OF LEAKAGE IN RESIDENTIAL HOUSEHOLDS T Britton, G Cole, R Stewart, D Wiskar Abstract Wide Bay Water Corporation is in the process of implementing aut omated met er read ing technology in their water network.

Th is technology allows t he remote measurement and eval uation of water consumption at a residential and commercial level using a FIREFLYÂŽ data logger and Com mstar software. By using the FIREFLYÂŽ, water usage patterns can be recorded each hour and stored for collection via a drive- by syst em.

This paper presents t he findings Figure 1. FIREFLYÂŽ and Water Meter installation at from a pilot study in Hervey Bay residential property.

Queensland that Wide Bay Wat er Corporation has undertaken in reason why customer billing records conj unction with Griffith University. The shou ld be regarded as the top is that objective was t o identify household wat er other levels of data are oft en derived leakage in residential properties located from the customer demand data. within a select ed district metered area Small and medium sized leaks in (OMA). Research outcomes incl ude a household plumbing are disguised water use profile of t he metered amo ngst legitimate customer demand. residential properties, the types of leaks The leaks may be undetected below encountered and the cost of leak repairs. ground, t hrough dripping taps and toilet At the commencement of the program cisterns. When considered individually it was found that 2% of the meters leaks may seem insignificant; however, accounted for 24% of the night time taken collectively over a long period they cons umption. This study provides result in a major loss of water evidence that automated meter read ing (Buchberger & Palli, 2004). The rate of technology can quantify water leakage water loss can vary depending on the beyond t he meter. type and severity of the leak. Generally, dripping taps can lose between 3-30 Introduction litres per day, leakage from toilet cisterns Water conservation consists of making can range from 10 litres per day for better and more efficient use of water invisible leaks to 340 litres per day or resources which implies a reduction in more for leaks large enough to be see water use or in water losses. Much has and/ or have an audi ble refi lling sound. been written and discussed about Troy & Randolph 's (2005) paper, which reservoir losses, seepage and leakage discussed water conservation from a from mains and services pipes; however, social and behavioural perspective, end use st udies on water losses at the indicated that 84% of survey household level, after the meter, have respondents said they knew of no leaks been limited. in their water pipes or fitt ings. Among the Obradovic and Lonsdale (1998) pointed minority who did report leaks, 7% said out that the lowest level in the hierarchy dripping taps were the cu lprit. Similar of d ata collectio n is the demand of individual customers. They suggested 2% of meters accounted that it might be a worthwhile exercise to invert the hierarchy since t he customer is for 24% of night-time the most important element in t he system. They stated that an important consumption.

find ings were also found by other studies. The AWWA report (Mayer et al., 1999) - Residential End Uses of Water (RE UWS) revealed t hat residential leakage problems typically occur in a smal l number of homes: nearly 67 % of homes in their study leaked on average 10 gallons per day or less, but 5.5% leaked more t han 100 gallons a day.

Yarra Val ley's Residential End Use Measurement St udy (Roberts, 2004) found t hat leakage accounted for 7.5% of total indoor use or 39 litres per day. The study noted the findings should be handled with care given the small sample size and that the leakage was concentrated in a relatively small proportion of t he homes. In t he Tampa ret rofit study (Mayer et al. , 2004) it was found that 38% of the leaking homes were responsible for more than 88 % of t he total per capita leakage. In some of t he houses t he source of the leak cou ld not be stated; running toilet, open tap, leaky sprinkler valve or slow leaking water pipe could cause 272 gallons lost per day. Moreover, some studies (Mayer et al., 1999:2004) recommended that a leak detection and repair program could significantly reduc e consumption ; however they did not examine the water savings potential.

Smart Metering The conventional metering system in Australia has a major limitation, i.e. meters only record t he total vol ume of water passing through and are not able to determine usage patterns. A smart meter is a normal water meter linked to a device t hat allows for the contin uous read ing of water consumption. The information is available as an electronic sig nal, it can be captured , logged and processed like any other signal (HauberDavidson & Idris, 2006), hence manual readi ng of t he meter is no longer req uired.

A n automated meter reading system (AMR) with this capabil ity provides benefits for both customers and water

water SEPTEMBER 2008 89

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asset management

The Pilot Study

authorities. Customers will be able to receive more detailed information about their water usage, allowing them to understand their consumption patterns. Information may also identify internal leaks, enabling customers to fix the problem, saving water and money. Data collected can provide a more accurate picture of a city's water consumption by identifying time-of-use and water use patterns for all consumers.

This will allow water authorities to develop targeted education campaigns relating to conservation and water use, and an opportunity to develop different tariff systems to influence consumer behaviour.

The objective of the pilot study was to identify household water leakage in a selected district metered area (OMA), the Point Vernon district (see Figure 2) using the automated metering system and subsequently implement a repair program to minimise water loss and assess the capability of the smart metering technology to identify in house leakage. By using the system, household leakage can be identified in two ways, i.e.: 1. Via an alarm which is picked up during the meter reading process. A trickle alert flags that no 'O' has been recorded in the previous 48 hours;

Wide Bay Water Corporation Figure 2. Location of Leaking Households in Point Vernon The City of Hervey Bay is situated on the Queensland coast approximately 300 including: decreasing water use, kilometres north of Brisbane. It is one of minimising water pumping and the fastest growing areas in Australia greenhouse gas emissions and with a current population of 54,000. The increasing infrastructure life. municipality covers an area of During 2007 Wide Bay Water approximately 2,350 square kilometres Corporation committed to the stretching from Burrum Heads in the implementation of a remote meter north to River Heads in the south, and reading system. This system wi ll combine encompasses the northern half of Heritage listed Fraser Island. drive-by water meter reading and data logging for all 22,000 domestic water Wide Bay Water Corporation is meters.

Queensland's only local government corporatised water business. Wide Bay All domestic meters in Hervey Bay Water Corporation provides water and have been replaced with new Elster V100 sewage services to the municipality and meters that have a FIREFLYÂŽ data logger also undertakes the planning, attached (Figure 1). The FIREFLYÂŽ development and operation of water records a magnetic pulse from the meter distribution infrastructure in the at a rate of one pulse per five litres. collection, distribution and disposal of These units are capable of recording water. hourly flow data, and transmit to a The application of smart metering in receiver on a hand-held computer or in a Hervey Bay was aimed at providing drive-by unit. The logger can store six customer consumption data for the first reads at four hour intervals each day for time at city-wide level. The smart meters a minimum of 120 days. The battery life and the policies that this technology for the logger and transmitter is expected enables will provide benefits to Wide Bay Water Corporation and its customers to last for a minimum of five years.

Table 1. Meter reading (litres recorded) on 23 October 2007.

Total Consumption 2359 meters

Consumption of 47 meters

47 Meters as % of total consumption

1 - 2am

6220

1350

21 .70

2 - 3am

5400

1260

23.33

3 - 4am

5520

1420

25.72

Time

90 SEPTEMBER 2008 water

DMA.

2. Via a review of the profile read when data is exported in to the software.

Research Approach The research process of the pilot study covered four phases, i.e. leak identification, household alert, plumbing audit and household survey. The details are outlined below.

Leak identification On 23rd October 2007, 2,359 residential meters were read in Point Vernon; 47 meters flagged a trickle alert; Figure 2 also illustrates the location of each leak.

Profiles of the 47 meters were downloaded providing information on water use for the previous 177 days. The raw data was examined; this provided hourly, daily and monthly data for each meter. In order to assess flow rates and total leakage post-meter, the leakage component had to be separated from consumption. Each meter was analysed individually each day between 1am - 4am to obtain an average minimum night flow.

The information was converted to a graph, illustrating a leak pattern as illustrated in Figure 3. The most consistent level of the flow was assumed to be the leak rate, and spikes were considered to be elements of consumption. The average flow rate for those 3 hours minus estimated consumption was assumed to be the average leak rate per hour - this leak rate was subtracted from the consumption volume in each hour of the day. This allowed us to monitor the consumption versus leakage and estimate hourly losses.

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asset management An example of a leak profile

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â&#x20AC;˘ Telephone Call o 2nd Letter

The leak pattern provides a visual display of t he leakage occurring over a t ime frame. Table 1 shows the total consumpt ion of all meters in Point Vern on and the 47 meters as a percentage of t he total. The hourly consumption between 1am and 4 am highlights that 2% of meters account for near ly 24% of recorded consu mption during that t ime.

yielded no response, a house visit was made in anticipation that a conversation may lead to participat ion. Figure 4 illustrates t he response to com munication

Household plumbing audit A contract plumber was employed throughout the d uratio n of the study in order to maintain the quality of w ork and to keep records of leaks and costs of repair. The repair program commenced on 5 November 2007 and ended on 5 December 2007. The plumber was employed for a total of 38 hours over this time.

Leak alert The 4 7 households whose meters flagged a trickle alert were contacted by letter st ating that they may have a potential leak. The letter offered a free household aud it and $100 towards repai r.

Households who d id not respond to t he initi al communicat ion were contacted by telephone one week later. A second letter was t hen sent t o t he remai ning households which provided more detailed information o n t heir actual leak rate including volume loss and dollar value and again encouraged part icipation. For t hose households who

Of t he 38 households who responded, 32 were audited at a cost of $60 each.

17 were repaired by W SW at an average cost of $89 and 17 undertook t heir own repair, with only three applying for rebate w ithin 8 weeks of the program.

The meters were read again on 20 January and the combined night t ime leakage/ consumption of those 47

Minimum Nightflow of 47 meters

1600 Repair Program

1400

~

1200 1000 <I)

~

:!:: ..I

800

f

I

/ '

"' \

- - 1am - 2am 2am- 3am

r-,... ,

600 400

3am - 4am

\

\ '

200 0 Sep-07

Oct-07

Nov-07

Dec-07

Jan-08

Figure 5. Change in minimum night flow as a result of the repair program.

o House Visit â&#x20AC;˘ No Response

Figure 4. Households Response to Communication. households had reduced from ca. 1300 to 356 litres per hour. In 11 (23 %) of t he households the leakage STILL accounted for over 70 % of t heir daily metered consu mption . Since 20 January, three more households have been repaired w hich brought the minimum night flow down to an average 173 litres per hour.

Six households that did not respond to co mmunicat ion no longer had leaks; it is assumed t hey undertook t heir own repair.

Project Cost and Savings Therefore the general sav ings as a resu lt of the program is 1095 litres per hour.

Figure 5 illust rates the change in minimum night flow as a result of the repai r program. The t otal cost of the program including project management and staff ti me was $5,168.27 (excluding rebates); mat erials accounted for $448.22. If t he properties had been allowed to continue leaking at the rat e of 1095 litres per hour then t he water lost wo uld amount to 26,280 litres per day and 9,565,920 litres per year.

The costs for intervention to undertake the identificat ion and repair program equated to $0.54 to save a kilolitre of w ater. The pilot study does not include t he cost of installing and maintaining t he meters. Once t he prog ram has been ext ended into ot her DMA's with more diverse cust omer bases, installation, maintenance and metering costs and the real cost of this water loss strategy using Least Cost Planning principles can be undertaken (White & Howe, 1998).

water

SEPTEMBER 2008 91

Q

asset management Household Survey

refereed paper

water bills of $300 for 3 years; suggesting a long runni ng leak.

The leaks accounted for over 73% of actual consumption and repair costs were $550 and $1200 respectively.

Do you think you have a leak?

The period monitored was from May 2007 to January 2008. 38 - ~ - - - - . - -- 21% out of 47 households responded â&#x20AC;˘ Yes to the letter and house visit. â&#x20AC;˘ Checked for a leak Among them 32 participated in 12% o No Galvanised pipe the survey, with a tot al of 82 people residing in these There were galvanised pipe households. The survey leaks at 3 homes; the pipe work Figure 6. Household awareness of leaks. requested information on basic was part of an external standing demographics, age of house tap. The area around the taps were replaced. The T-Junction leak was {Table 2) and type of plumbing materials. was greener in comparison to the rest of found using leak detection equipment 62% of respondents said they there was the garden and the ground damp to aft er several unsuccessful digs. The no leak, 12% checked for leaks after touch. sounding stick located the leak and receiving the letter and 21 % thought that Taps digging recommenced, the pipe was they had a leak (Figure 6). lying upon gravel bed and the water was There were 5 kitchen taps and 2 external The run time of identified leaks ranged seeping below ground. taps leaking. Washers were replaced on from 6 days to 277 days and the average all taps except one; the set of taps were leak duration was 156 days. The range of Copper pipes replaced with a flick mixer. When household loss was 864 litres to 310,262 Copper pipe leaks were found at 2 studying the leak graph of two further litres and the leak flow rat e varied from homes; one home was built in 1960 homes an erratic pattern was presented 5.56 litres per hour to 343 litres per hour.

1969 and the other between 1970 and which involved no recorded consumption The lowest flow rate that the meters can 1979. The older property had two toilet on some days. The plumbing audit could reliably detect is 3.33 litres per hour. The leaks and a suspected supply pipe leak; not find evidence of a leak and after total water lost during that period for 47 which cou ld not be located. The house further discussion, it was established that meters was 4.2 ML. It is possible to was monitored after repair of the toilets one occupant had difficulty in turn ing off determine the start date of the leak, run and there was a steady increase in the the taps due to an arthritic condition and time and peak flow rate: the meters flow rate from 15.57 litres per hour the other admitted to not always turning commenced data logging in May 2007. peaking 6 weeks lat er at 93 litres per the taps off completely. hour. When the toi lets were fixed, the Types of Leaks Identified Toilets pressure would have increased because This study identified seven major types the effective "relief valve" offered by the There were 21 leaking toilets; five of leaks, Figure 7 illustrates the number leak had stopped , thus decreasing flow properties were experiencing leaks in of leaks by leak type, among them toilet and increasing pressure. If the leak was a both toi lets. An audible hiss could be leaks represent 46%. The following corrosion hole in the copper pipe, then heard upon entering many homes. There sections discuss each leak type in detail. particles of weak material would have were 8 dual flush toilets with cistern size Supply pipes post meter - plastic been lost making the hole slightly larger 6/3 litres, leaking in the range of 13.3 pipes and the flow greater; due to the pressure litres per hour to 343 litres per hour. The plumber confirmed and size of hole.

A size of the latter leak was a result of a There were 3 leaks on the plastic pipe that copper pipe work was leaking stuck full-flush toilet button in an empty post meter; 2 were longitudinal splits in beneath the house and new pipe lagging rental property. Th e owner was notified the polyethylene pipes and one was on a and turned the water off until the was applied to the existing pipe. The T-J unction. The splits were at what arranged repair date; this leak ran for 18 1970's residence had major pipe work appeared to be a weak point in the days. There were 5 leaks in dual flush replaced beneath the house.

The flow polyethylene as the thickness of the pipe toilets with cistern size 9/4.5 litres: the rate was a steady 36 litres per hour. A was not uniform. The pipes were range of flow rates was 13.3 litres per check of historic billing records showed monitored over several weeks, looking hour to 35.6 litres per hour. There were 8 that the customer had received annual for evidence of damp patches. The property owners took meter read ings last thing at night and first thing in the Leak Types morning, both reported a progressive ~- - increase in the flow rate. The leaks finally Not Confirmed _L,._ appeared after 4 weeks, a successful dig No Leak located the leaks and the split sections lrri~tion Hot Water System

Table 2. Age of leaking households

Meter

~ -r- I I

Toilets

I

Age of house Before 1969 1970-1979 1980-1989 1990-1999 2000-2005

92 SEPTEMBER 2008 water

T aps

18.75% 34.37% 12.50% 28.12% 6.25%

I -

0

I

.

I

-

-

I

Pipes

11

I

I

2

3

4

5 6

I

I 7

8

I

I

-

I

I

I

I

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Number of Leaks

Figure 7. Type of Leaks Identified.

technical features

asset management

[;] refereed paper

Table 3. Average leak flow rates according to toilet type.

Toilet Type 6/3 9/4.5 Single

Min Flow/Hour

Max Flow/Hour

Average Flow/Hour

13.3 13.3 12.2

343 35.6 38.9

16.7 (excl 343 outlier)

leaks in single flush toilets, the f low rates ranged from 12.2 litres per hour to 38.9 lit res per hour, the cistern size ranged from 11 - 15 litres capacity (Table 3). The majority of toilet leaks were caused by failure of the 'top valve' in t he cylindrical control units in t he cisterns. Further study wi ll investigate why are so many toilets are failing.

Other leaks There were three meter problems; two service nuts were loose and one meter had been damaged by building works.

There were two hot water system leaks and a faulty timer on an irrigat ion system.

There were 11 leak types not confirmed, however an assumption of the leak is made according to the graph pattern.

Summary The pilot study demonstrates that this technology can more accurately account for water losses at the end user level, some key findings regardi ng leak characteristics include: • 2% of t he meters accounted for 24% of consumption between 1am - 4am.

• Toilets accounted for 46% of t he types of leak.

• Leaks occurred in both the old single f lush and the newer efficient models.

• 21 % of households who said that they knew of a leak; stated t oi let and tap problems.

• 19% of homes did not respond to any form of comm unication.

• The homes t hat experienced leaking pipes were not aware of the problem even when the leaks were large.

• Leaking taps can be fixed at the lowest cost.

• Lagging to copper pipes was the most expensive repair.

From a water business perspective t he direct cost of intervention for this pilot program has been assessed as $0.54/kL and th is gives strong incentive to extend the program into more DMA's allowing t he real cost of t his water loss management strategy to be determined using Least Cost Planning principles. The

20 19.4

comprehensive coverage of all residential and commercial meters throughout the city provided a unique opportunity to remotely monitor the usage and leakage components of al l forms of water consumption. This information has implications for post meter leak detection, water loss prediction models and the development of effective policies to reduce such losses.

The Greater Study The pilot study was the first stage of a larger research project involving Griffith University and Wide Bay Water with fu nding provided by t he Aust ralian Research Council. The p ilot study raised some important research questions; should we tolerate losses in households even t hough water has been metered and paid for? How do you enforce repair, who pays and what are t he social and political ramifications? Would this type of enforcement be pursued only in times of water scarcity? Is leak identification and rectification a least cost water conservation approach?

The greater study is currently expanding to other district metered areas of Hervey Bay and research objectives include quantifying the level of residential water loss; understanding the p hysical and behaviour reasons for the losses; quantifying the water savings potential and applying Least Cost Planning to investigate the cost and benefits of implementing active leakage control at the residential level and place in context alongside other demand management options.

The next phase of st udy wi ll also consider what impact real time consumption data has on water planning and management of water resources.

What is the night time consumption of residential households in Hervey Bay? Does the night t ime consumption compare to estimates of consumption in other national or international regions?

What is the end use consumption attributed to household leakage in Hervey Bay? Does t he amount of household leakage compare with earlier end use studies in Australian regions?

The research will explore policy approaches for residential water loss management and the implications for relevant stakeholders; government t hrough to customers. Finally, t he greater study seeks to provide robust evidence that leakage identification and repair rectification is a viable strategy for ensuring the sustainable conservation of water resources.

Acknowledgments The authors wish to acknowledge support from The Institute of Sustainable Futures and Dr. Rob Fearon at OLD Water. Particular thanks to Dr. Le Chen, Griffith University and Wide Bay Water Corporation for access to their facilities especially Bruce Yarrow and Kylie Borg in the Water Billing Department.

The Authors Tracy Britton is a PhD Candidate, (Tracy.Britton@student. g riffith.edu. au); Dr Rodney Stewart is a Senior Lecturer, Griffith University, Queensland; Graham Cole is Research Officer, and David Wiskar is General Manager, Wide Bay Water Corporation, Queensland, davidw@widebaywater.qld.gov.au

References Buchberger, S.G., & Palli, N. (2004) Leak estimation in WDS by statistical analysis.

Journal of Water Resources Planning & Management 130 (4).

Hauber-Davidson, G., & Idris, E. (2006) Smart Water Metering. Water Journal of the Australian Water Association. 33(3)56-59 Mayer, P.W. , DeOreo, W.B., Optiz, E.M., Kiefer, J.C., Davis, W.Y., Dziegielewski, B., & Nelson, J.O. (1999) Residential End Uses of Water. American Water Works Association Research Foundation.

Mayer, P.W., DeOreo, W. B., Towler, E., Martien, L., & Lewis D.M. (2004) Tampa Water Department Residential Water Conservation Study; The impacts of high efficiency plumbing fixture retrofits in single family homes. Aquacraft, Inc.

Obradovic, D., & Lonsdale, P. (1998) Public Water Supply: Models, data and management. New York: Routledge.

Roberts, P. (2004) Yarra Valley Residential End Use Measurement Study.

Troy, P., & Holloway, D. (2004) The use of residential water consumption as an urban planning tool: a pilot study in Adelaide. Journal of Environmental Planning and Management 47(1) 97-11.

White, S., & Howe, C. (1998) 'Water Efficiency and reuse: a least cost planning approach' Proceedings of the 6th NSW Recycled Water Seminar.

water SEPTEMBER 2008 93

wastewater treatment

Cs]

refereed paper

MIEX® TECHNOLOGY DECOLOURISES A PAPERMILL RECYCLE STREAM S Chopra, A Holmquist, B Murray Abstract

Table 1. Raw Whitewater Characteristics

Recycled paper production at Visy Raw Whitewater Industries ('Visy') consumes approximately 4,000 litres of fresh water per tonne of True Colour (pt-Co) paper produced, which is below industry Charge Demand (µEq/L) average. Increasing fresh water recycling UV254 Absorbance (cm-1) can concentrate contaminants, affecting Turbidity (NTU) product quality and chemical usage.

Chloride (mg/L) Magnetic ion exchange ('MIEX®') TDS (mg/L) treatment was evaluated on effluent ('whitewater') from recycled paper BOD (mg/L) production at Visy Coolaroo, COD (mg/L) demonstrating colour and charge demand reductions of 74% and 80% respectively, thus enabling increased fresh water recycling for white t op liner production and further reducing fresh water usage by up to 15%. A full-scale system has now been installed and commissioned, demonstrating innovative technology application and the world's first MIEX® Treatment plant for industrial use.

Introduction Water scarcity has placed immediate pressure on high water users, particularly industrial companies, to reduce water usage and increase water efficiency.

Visy produce a wide range of paper and packaging products and use recycled papers for paper production. Recycled paper production at Visy consumes approximately 4,000 litres of fresh water per tonne of paper produced, which is below the industry average. Although Visy recycle over 95% of fresh water used during recycled paper production, large volumes of effluent are still discharged from Visy's Coolaroo site in Campbellfield, Victoria.

250 355 2.862 390 67 2350 1683 3820

The MIEX® Resin is used in a continuous ion exchange process incorporating resin contacting, separation, and regeneration. A single process vessel performs each stage of resi n contact and separation whilst resin regeneration occurs in dedicated equipment. Figure 1 depicts the MIEX® Treatment process.

This configuration is a counter current MIEX® System that consists of two high rate reactor vessels connected in series.

Raw water flows from vessel to vessel in one direction , while resin is pumped from vessel to vessel in the opposite direction.

Fresh regenerated resin is fed to the second or final reactor vessel whi le loaded resin is removed from this vessel at the same rate and sent to the preceding first reactor vessel. Loaded resin from the first reactor vessel in the series is sent to regeneration, hence providing a counter current MIEX® Treatment system. This allows fresh resin introduced into the second or final reactor vessel to act as a polishing step to remove remaining contaminants, while partially loaded resin introduced into the first reactor vessel is contacted with the Reactor Vessel 1

Whitewater from recycled paper manufacture is coloured and has a high charge demand. Highly coloured water will negatively impact the brightness of white t op liners manufactured in this paper mill, and high charge demand will increase the amount of chemicals required to produce recycled paper. Table 1 shows typical values for the whitewater.

Visy set an internal target of reducing water usage by 20% and investigated treatment options that would enable recycling of treated whitewater back into the recycled paper manufacturing process.

magnetised component within their structure, allowing them to act as weak individual magnets. These magnetic particles form rapidly settling agglomerates, enabling application under mixed conditions and allowing the process to be relatively unaffected by high suspended solids loadings. The very small resin bead size of around 200 mm provides a high surface area faci litating rapid kinetics.

Reactor Vessel 2

Fresh resin to reactor

..

Raw Water

Technology Description The MIEX® Technology is an innovative anion exchange process. The name 'M IEX®' comes from Magnetic Ion EXchange, because the resin beads contain a unique

SaltBrine Tank WaS te...

The first industrial application, at ML/d scale.

94 SEPTEMBER 2008 water

Brine

~~

LJ .

I

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I Re;eneration Vessel

Figure 1. MIEX® Process.

technical features

~ refereed paper

Raw

wastewater treatment

,------;::::====::;----------, a

300

Post MIEX®

Raw Effluent

a Treated

250

235

B'250 'E ~200

~

-;:'150 ::, 0

8100

75

Cl

2 to-

61

50

0 + - -- - MIEX® Treatment Only

Figure 2. True Colour Reduction.

Figure 3. True Colour Results.

450

most contaminated stream, therefore loading t he resin more comp letely before regeneration.

M IEX® Resin can be regenerated using sodium chloride, sodium bicarbonate, sodium sulphate, or potassium chloride.

The volume of waste regenerant prod uced is typically less than 0.1 % by volume of the total treated flow.

W h ile standard MIEX® Systems incorporate a single high rate react or vessel , a counter current configuration is well-suited for treating industrial wastewaters with high contam inant loads. The cou nter current contacting of raw water with MIEX® resin al lows highly selective anions to be removed with partially loaded resin in t h e first reactor vessel so that fresh resin added to t he final reactor vessel will remove additional target contaminants, or less selective anions. The efficient sequential loading of MIEX® Resin reduces t he regeneration system size, al lowing significant reductions in waste volumes, salt consumption and associated operating costs.

Pilot Study Results Although the MIEX® Tech nology was originally developed for removing dissolved organic carbon (DOC) from potable water supplies, its characteristics lend itself to removing anionic contaminants from commercial scale industrial wastewaters.

Initial laboratory testing of wh itewater from Visy Coolaroo indicated t hat contaminants present in the whitewater were amenable to MIEX® Treatment; therefore, further pilot scale testing was conducted to demonstrate long-term performance and optimise operating parameters.

A pilot plant trial was conducted during February and March of 2007 incorporating PETAX™ pre-filtration followed by the

PETAX Filtration+ MIEX® Treatment

,------~~=;;::=:;---d 41' 141 - - - - - , II Raw Effluent

400

355

~ 350

•

Treated

§. 300 "g 250 1200 ~ 150

:v

91

5 100

82

50 0 + - ------' MIEX® Treatment Only

PETAX Filtration+ MIEX® Treatment

Figure 4. Charge Demand Reduction.

•

NSW Depanment of

Commerce

Office of Public Works and Services

A

CLE XA N-PEA K PUSONNIL

Senior Mechanical or Civil Engineer (Wastewater Services) An intellectually challenging and socially important role for an experienced engineer, with the Office of Public Works and Services in Sydney CBD. The Salary Package is $ 11 3,277 P.A. The successful applicant wi ll manage the application of Civil/Mechanical Services and related works associated with water supply and wastewater projects. You wil l lead and manage multidisciplinary teams in concept development, design and commissioning of services for a wider range of projects, and wi ll deliver innovative solutions and advice to clients. You will be involved in planning the strateg ic direction of wastewater services in NSW and wil l assist in marketing and business development.

You will have 15 - 20 years experience in investigation, design and com missioning of wastewater infrastructure and have a degree in Mechanical or Civil Engineering. You will have a proven record of driving complex projects to meet time, cost and quality pa rameters.

Qualified Engineers would be welcome to apply.

Please contact Ray Murray for a confidential discussion on (02) 9876 8888.

Figure 5. Implementation at Visy.

water SEPTEMBER 2008 95

wastewater treatment MIEX® Process. PETAX™ pre-filtration was used to remove large paper fibres (> 100 mm) and MIEX® Treatment was used to lower colour and charge demand levels.

The results demonstrated that MIEX® Technology can reduce true colour and charge demand by an average of 74% and 80%, respectively, thus enabling whitewater to be reused in white top liner production without affecting paper colour or brightness. The reduction in true colour is demonstrated in Figure 2.

MIEX® Treatment was evaluated on whitewater without pre-filtration in addition to whitewater that was filtered at 100 µm. Figures 3 and 4 demonstrate that pre-filtration has a minimal affect on reducing true colour and charge demand using MIEX® Treatment.

Although water quality performance was similar with and w ithout filtration, pre-filtration is recommended to provide the best hydraulic performance throughout the MIEX® Process.

assessed coagulation, ozonation, and anaerobic processes to meet colour and charge demand reduction targets. Wh ile these processes can reduce colour, high chemical/energy usage, large footprints, and high initial capital costs associated with these technologies would likely be required to meet targets. The MIEX® Technology was selected for full-scale implementation based on technical feasibility, minimal plant footprint and capital costs, and low energy use and waste volumes.

A commercial scale plant with a one megalitre per day (1 MLD) c apacity has been installed and is being commissioned. Wh itewater from the paper machine w ill be treated by PETAX™ filtration followed by MIEX® Technology and reused in the paper making process. Figure 5 shows the fu llscale MIEX® Technology implementation on site.

Conclusions

Project Outcomes

Recycling whitewater provides the following economic and environmental benefits to Visy:

In addition to investigating the MIEX® Technology for treating w hitewater, Visy

• Reduces site fresh water usage by 15%, therefore helping to achieve the

0

refereed paper

target of reducing overall fresh water usage by 20% • Provides water security to Visy for recycled paper manufacturing, despite water restrictions • Significant production cost savings via red uctions in fresh water usage and trade waste production • Implementing the MIEX® Technology in this application is an innovative use of the tech nology and represents a worldfirst in using this process for treating industrial waste streams.

Acknowledgments Orica wishes to thank Visy Industries for their contribution in the preparation and execution of this project.

The Authors Sunil Chopra is the Technical Manager Paper at the Visy Technology and Innovation Centre, Campbellfield , VIC ; Abigail Holmquist is the MIEX® Business Development Manager, at Orica Watercare USA, Denver COL; Brendan Murray is the MIEX® Business Development Manager, Orica Australia, Melbourne, email brendan.murray@orica.com.

Intelligent Sustainable Water Solutions Water Technology Australia is a leader in water and wastewater treat ment plant design, construction, installation, commissioning and system maintenance throug hout Australia.

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Call Bill Kelly for more information on 02 9899 7811.

wastewater treatment

Q

refe reed paper

WETLANDS MINIMISE ALGAL GROWTH IN A HORTICULTURAL CENTRE C Hanley, M P Taylor Abstract Constructed wetlands at a northern Sydney garden centre were evaluated for their efficacy for removi ng excess nitrogen and phosphorus within the site's internal water network. The original construction of the centre utilised the latest technology for water harvesting, storage and irrigation to ensure a permanent high quality water supply with minimum reliance on Sydney Water drinking water supplies. A series of artificial wetlands was built to assist in the removal of nutrients and improve water quality. The wetlands are effective at removing 95% of t he total nitrogen (TN) and 98.5% of the total phosphorus (TP) . Biological oxygen demand (BOD) also decreases throughout the system from 10mg/L to < 4 mg/L. Despite the initial success, a pump failure during 2007 resulted in widespread algal growth throughout the centre's reticulation network. Consequently, th is study was designed to evaluate the sources and causes of the problem, to optimise the reed bed technology and to develop recommendations to mitigate future algal bloom events.

Key words: constructed wetland; nutrient removal; garden centre; algae

Introduction The horticultural industry in Australia is subject to negligible legislative requirements with regards to water management. The Nursery Industry Water Management Best Practice Guidelines (Atkinson , 2005) provide a practical guide to managing water, but they are not legally binding. The Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC, 2000), include information and guidelines for primary industries, but these do not cover specifically the horticultu ral industry.

Environmental issues have come to the forefront of business practice in recent years with the advent of initiatives such as corporat e social responsibility (CSR), and workplace sustainability. Th e garden

98 SEPTEMBER 2008 water

centre industry is an area where improvements can be made in water savings, and the use of eco-technology can be implemented to improve water quality, subsequently reducing the industry's impact on the environment.

Further, efficient environmental business practices within a garden centre can be used as a sales and marketing opportunity to highlight new tech nologies for water management to their domestic customers.

The horticultural industry has two primary issues to manage. Firstly, it is a consu mer of large vol umes of water for irrigation purposes. Secondly, runoff water quality is poor due to high concentrations of nutrients (predominantly nitrogen and phosphorus) that occur as leachates from containerised plants. These elevated nutrient levels in runoff have the potential to subsequently cause algal blooms, that in t urn, reduce further the water quality.

Algal growth occurs when there is an excess of nutrients coupled to still or slow moving water, sunlight and warmth.

The main nutrients required are carbon dioxide, nit rogen and phosphorus.

However, the ANZECC (2000) water quality guidelines for primary industries states that "no trigger value for algae in irrigati on waters is reco mmended; however, excessive algal growth may indicate nutrient pollution of the water supply". Both phosphorus and nitrogen are macronutrients for algae, but conditions that trigger or contri bute to algal blooms fl uctuat e both temporally and spatially (Headley et a/., 2002).

This article outlines the results and recommendations of a study undertaken at Eden Gardens and Garden Centre (the "Centre"), North Sydney, which examined the efficacy of their constructed wetlands

Optimising reed bed technology for den itrification.

for removing nutrients from their reticulated irrigation system.

Constructed Wetlands Natural wetland filtration of catchment runoff has been occurring naturally for millions of years. The benefits of constructed artificial wetlands were first real ised when Kathe Seidel carried out t he first recorded experiments using wetland macrophytes for wastewater treatment in the early 1950s (Seidel, 1955). Seidel realised that vegetation in wetland areas sequestered large quantities of nutrients and metals by storing them in the roots and shoots, thereby improving the quality of water as it leaves wetland systems (Bragato, 2006; Vymazal, 2005).

Constructed wetlands (or reed beds) have several distinct advantages over man-made water purification systems.

They are able to remove a large proportion of the nitrogen and phosphorus load with no requirement for power, have a relatively low cost set up and negligible ongoing maintenance costs. Aquatic plants boost nutrient removal through biomass accumulation along with the fixation of inorganic (e.g. metals) and organic particulates (e.g. hydrocarbons, bacteria) (Davison et a/., 2006; Huett et a/., 2005). Thus, constructed wetlands are designed to take advantage of the processes that occur in natural wetlands. A substrate bed depth of only 0.8m wil l allow the root s of wetland plants (e.g. Phragmites australis) to penetrate the bed and ensure oxygen is delivered t o the whole bed through its release via the rhizomes (Vymazal, 2005).

Studies by Huett et al. (2002) show that nursery runoff typically contains 10mg/L Total Nitrogen (TN) and 0.5mg/L Total Phosphorus (TP). Consequently, because of such elevated levels of nutrients, storage dams often become contaminated with algal blooms, which can raise the pH of water to levels as high as pH1 0. This prob lem is exacerbated when water is continually

technical features

GJ

wastewater treatment

refereed paper

recirculated and leachates are continually added (Headley et al., 2005). A range of measures including the use of constructed wetlands can be utilised to ensure that nutrients are removed and water quality is improved prior to the water entering the storage facility, and before reuse.

The Study Site The Centre is a purpose-built, state of the art facil ity that has been designed to grow, maintain and sell ornamental plants while harvesting, storing and treating its own irrigation supply based on eco-technological principles.

Upper Oarde11 wetland

The Centre is divided into two distinct areas (Figure 1): 1. The upper garden centre with a 250KL storage tank, gravel and sand filters and constructed wetland, and 2. The lower display garden with a 750KL storage tank and const ructed wetland.

The two areas operate independently for most of the year, except when overflow water is pumped from the upper garden centre to the lower display garden during heavy rainfall, and water is pumped from the lower display garden to the upper garden centre when additional water is required in that area. Continuous flow is maintained in both the upper and lower sections of the Centre by permanent 24 hour pumping systems. Unfortunately there are no meters installed to measure precisely water flow Figure 1. Plan of Eden Gardens showing garden centre and display rat es. However, water is supplied to the upper garden gardens (modified from Perrens Consulting, 2002). centre wetland at a rate of 36m3/hr (10 Us) from the 250 KL storage tank. In the lower display garden water is preventing further algal blooms. Sample 1 was t aken in the supplied to the constructed wetland at a rat e of 180m3/hr garden centre reed bed, sample 2 in the garden centre storage or 50 Us. These should be considered minimum flow rates, as and sample 3 from the contai nerised plants as per the pouradditional water periodically moves through the system during through extraction method (Rolfe, 2000), sample 4 from the car wat ering/irrigation and from natural rainfall ru noff. park ru noff, sample 5 from the lower display garden wetland , The lower display gardens wetland is planted with Iris and sample 6 from the display garden storage tank (Figure 1).

Louisiana, Baumea articulata, Typha orientalis and Canna X In addition, pH and temperatu re were measured with a genera/is , along with Lomandra tanika and Co/ocasia escu/enta.

Hanna Instruments HI 9025C meter calibrated to pH 4 and pH Th e upper garden centre wetland is planted with Iris Louisiana, 7. Dissolved oxygen was measured with a Hanna Instruments Baumea articulata, Typha orientalis, Canna X genera/is along with Cyperus papyrus, Juncus kraussii and Lepironia articulata.

The wetlands were successfu l in preventing algal growth until April 2007, when a major pump in the lower display garden broke down and water circulation ceased for several weeks. This prompted an outbreak of green algae that has been present continually at the site.

The ideal filter medium

Methods

•

Six water samples were taken in January across the Centre in both the garden centre and display gardens. Care was taken to collect all samples with in one hour for consistency.

• • • • •

The purpose of sampling was to establish areas of high nutrient concentration and to investigate the efficiency of the reed bed filtration systems in

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[:;] refe r eed paper

Table 1. Test results.

Location

Sample Number

Temperature (' C)

pH

Dissolved oxygen (mg/L) [%]

Electrical conductivity (dS/m)

Total Nitrogen mg/L

Total Phosphorus mg/L

Biological oxygen demand mg/L

<4 <4

1

Garden centre wetland

24.7

6.88

6 [70%]

0.398

0.31

0.053

2

Garden Centre storage tank

25.2

7.01

6.5 [75%]

0.386

0.21

0.064

3

Potted plant

nla

n/a

n/a

n/a

12.0

5.1

10

4

Car park run off

n/a

n/a

n/a

n/a

1.2

0.14

5

Display garden wetland (upper garden centre)

25.9

8.34

8.5 [100%]

0.582

0.6

0.054

<4 <4

6

Display garden storage tank (lower display garden)

26.4

8.42

9.4 [110%]

0.571

0.52

0.07

4

n/a

25.5 - 7.0

17.5-11

20. 75 - 3.0 dS/m [60-120%]

1<5.0

1<0.05

1<12

Recommended Limits•

*1. ANZECC Guidelines for Fresh and Marine Water Quality (2000).

2. Nursery Industry Water Management Best Practice Guidelines (Atkinson, 2005).

HI 9142 meter. The meter was calibrated t o 0% oxygen at Macquarie University, and to 100% oxygen in the field at the start of testing. Electrical conductivity was measured with a Hanna Instruments HI 9033 meter calibrated to 1413 µs/ cm. All instruments were cal ibrated 24 hours prior to use.

Water samples were collect ed in acid washed containers provided by the National Measurement Institute (NM I) at Pymble (NATA approved). Samples were kept in a cool box at -<4°C and a few hours after collection, they were delivered to the NMI for total phosphorus, total nitrogen and biologic al oxygen demand analysis.

Result s and Discussion Temperature Although there is little control over water temperature with in the Centre, it should be noted that temperature has a direct influenc e on dissolved oxygen c ontent and biological oxygen dem and. Water temperature influences the survival and growth of algae, with warmer temperatures increasing the rate of photosynthesi s (Vymazal, 1995). There are no water tem perature guidelines either in ANZECC (2000) or the Nursery Industry Water Management Best Practice Guidelines (Atkinson , 2005).

pH

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ANZECC Water Quality Guidelines (2000) recommend a pH level between 6.0 and 8.5 should be maintained to limit the corrosion of pumping and irrigat ion systems. The pH levels within the centre (Table 1) fall within this range, but the water in the lower display gardens is more than an order of magnitude more alkaline than the level in the garden centre and exc eeds recommended water quality guidelines values. This is most likely due to the algae present in the lower display gardens, as algal photosynthesis will increase the pH level of water t o up to pH1 0 (Headley et a/., 2005).

Dissolved oxygen (DO) Nitrification/denitrification is the major removal mechanism of nitrogen in artificial wetlands. Insufficient dissolved oxygen content is considered to be one of the major factors that influence this process as oxygenation of the rizosphere is often insufficient in constructed wetlands (Vymazal, 2005). ANZECC (2000) guidelines recommend DO levels between 60% and 120% and all samples fall withi n this range (Table 1). However, it should be noted that the samples were taken in the middle of summer, when water temperatures were high. The DO concentrations in the garden centre are likely t o fall below these guidelines when the water temperature falls below 18°C during winter. Therefore, the values measured during this study are considered borderline and indicate a lack of aeration in the system. The consequences for the reed beds are that they would operat e during the winter at a sub-optimal level.

Electrical conductivity (EC)/ salinity Plants vary wid ely in their salt tolerance. Water with salt levels up to 0.625 dS/m (400 mg/L) are consid ered to suit most cond itions except the most sensitive of plants (Atkinson, 2005).

The display gardens had higher EC levels than the garden

technical features

Q

wastewater treatment

refereed paper

centre, but all areas are well withi n the Nursery Industry Water Management Best Practice Guidelines (2005) levels of 1 dS/m.

Biological oxygen demand Biological oxygen demand (BOD) is a measure of the oxygen used by microorganisms to decompose waste and is used as a measure of water quality. There are few guidelines for BOD, but the guideline limit for freshwater aquaculture is 12 mg/L (ANZECC, 2000). Water with high levels of o rganic waste will have elevated levels of bacteria, which assist in decomposing the waste. Consequently, the demand for oxygen will be high so the BOD will be high. Biological oxygen demand levels decrease as the waste is consumed. All the samples fall below the guideline limit for BOD, implying that general water quality is good.

Total nitrogen Short-term trigger val ues and long-term trigger values have been used to develop guid elines for both total phosphorus (TP) and total nitrogen (TN) by ANZECC

(2000). Excess amounts of nitrogen can promote algal growth and over-stimulate plant growth. The long-term value (5 mg/L) is set to ensure no decrease in crop yields, and the short-term value (25 - 125 mg/L) has been set to minimise the risk of contaminating ground and surface water. As anticipated, leachate from the plants in the garden centre show significantly elevated nitrogen levels, well above guideline levels (Table 1).

However, results from the other samples indicate that nitrogen removal is high, and the filtration systems are reducing nitrogen levels by up to 98% to levels well withi n the accepted long-term range.

Total phosphorus Phosphorus is considered to be the primary nutrient responsible for algal growth. The long-term value (0.05 mg/L) has been set to prevent algal growth in irrigation water. The short-term value (0.8 - 1.2 mg/L) is an interim range given due to limited data (ANZECC, 2000).

Phosphorus levels in the pot plant sample are 100 times higher than th e recommended levels at 5.1 mg/L. Although phosphorus levels are being

significantly reduced by filtration in the Centre's system, levels remain above the guidelines in all areas tested.

Discussion The results clearly show that high levels of leachate, rich in phosphorus and nitrogen, are ent ering the water irrigation and storage system. Nitrogen is being efficiently and effectively removed by the reed bed filtration system. Phosphorus is being removed, but not to the levels required to minimise the potential of an outbreak of algal growth.

Dissolved oxygen concentrations are higher in the display gardens where there is more aeration of the water due to the design of the wetland. Lower levels of dissolved oxygen in the garden centre reflect a lack of vertical flow and aeration in this area. As DO levels are well within the ANZECC (2000) guidelines, this suggests that in the lower display gardens this is unlikely to be a contributing factor to the algal bloom that had occurred in this area. Biological oxygen demand is consistently low and indicates good water quality across the Centre. Similarly, electrical conductivity

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Table 2. Brief overview of the efficiency of different wetland macrophytes for nutrient removal in wetland systems. n.d. - no data.

Common Name

Plant

N uptake

P uptake

Reference

Bolboscheonus fluvialtilis

Marsh Clubrush

n.d.

89%

Carex /acustris

Sedge

93%

63%

Shaver and Melillo (1984)

Hibiscus cannabinus

Kenaf

100%

n.d.

Davison et al. (2006)

Phragmites australis

Native reed, thatch reed

90%

96%

Dirou et al. (2003)

84%

n.d.

Davison et al. (2006)

90%

96%

Huett et al. (2005)

83%

100%

Wathugala et al. (1987)

90%

80%

Tanner (1996)

95%

97%

Gersberg et al. (1983)

91%

88%

Laouali et al. (19960

61%

99%

Brix et al. (2003)

65%

72%

Mander et al. (2003)

n.d.

95%

Lantzke et al. (1998)

97%

Gersberg et a/.(1983)

500 Kg/ha/day

n.d.

Davison et al. (2006)

91%

88%

Laouali et al. (1996)

River Club-rush

Schoenoplectus validus

Tanner (1996)

Tanner (1996)

90%

Scirpus spp.

Hairy sedge

Setaria sphacelata

Perennial pasture grass (requires monthly harvesting)

95%

Typha latifolia

Common Cattail

65%

72%

Mander et al. (2003)

Typha orientalis

Cumbungi, bullrush

n.d.

67%

Lantzke et al. (1 998)

Typha spp.

Cumbungi, bullrush

95%

97%

Gersberg et al. (1983)

Zizania latifolia

Manchurian Wild Rice

59%

n.d.

Tanner (1996)

Planted wetlands

Plants unknown

82%

n.d.

Kohl and McKim in Gersberg et al. (1983)

Planted wetlands

Plants unknown

90%

n.d.

Boyt et al. (in Gersberg et al. 1983)

Planted wetlands

Plants unknown

65%

n.d.

Bouwer et al. (in Gersberg et al. , 1983)

Planted wetlands

Plants unknown

90%

n.d.

Ingersoll et al. (1998)

levels are only unsuitable for the most sensitive varieties of plants. pH is within the recommended range in t he upper garden centre, but above guideline levels in the lower display garden. The elevated pH is most likely caused by the algal photosynthesis (Headley et al., 2005).

Conclusion Environmental management, and more especially water supply and water quality, represents a great compet itive opportunity for businesses to develop innovative and environmentally friendly solutions. Historically there has been a tendency to over-fertilise contai nergrown crops leading to high levels of nutrient leachates in run-off waters and this is reflected in t he results of the water testing. However, overall, ou r study of Eden Gardens demonstrates t he ability of artificial wetlands to maintain good water quality parameters even under the high

Nitrogen is being efficiently and effect ively removed by the reed bed filtration system. Phosphorus is being removed, but not to the levels required to minimise the potential of an outbreak of algal growth. This issue needs to be addressed with additional macrophyte planting in the reed beds, and annual late summer or early spring harvesting to maximise nutrient uptake efficiency and prevent the redistribution of nutri ents to the rhizomes (Headley et a/., 2005).

Examp les of suitable aquatic macrophyte species for add itional planting withi n the centre are listed in Table 2.

Acknowledgments We thank Eden Garden's for sponsori ng this research t hrough t he Macquarie University's Division of Environment and Life Science's Work Integrated Learning and Research Prog ram. We also thank Ms Penny Wilson for her help in setting up the project.

nutrient load conditions experienced in a garden centre. The Centre's technology represents best practice for on site water management and provides a good model for other similar business's who are considering more sustai nable water management opt ions.

102 SEPTEMBER 2008

water

The Authors Claire Hanley is a graduate student and Mark Patrick Taylor is an Associate Professor in the Department of Physical Geography, Macquarie University, North Ryde , Sydney, NSW 2109, Australia.

Contact emails: claire_david@bigpond.com; mark.taylor@mq.edu.au; Tel: 02 9499

3436.

References Atkinson I (Ed) 2005, Nursery Industry Water Management Best Practice Guidelines, Nursery and Garden Industry Australia, Epping, NSW. Australia and New Zealand Environment and Conservation Council (ANZECC). National Water Quality Management Strategy, The Australian and New Zealand Guidelines for Fresh and Marine Water Quality, Chapter 4 - Primary Industries.

Department of the Environment and Heritage, Canberra, Australia, 2000.

Bragato C, Brix H and Malagoli M, 2006.

Accumulation of nutrients and heavy metal in Phragmites australis (Cav.) Trin. ex Steudel and Bolboschoenus maritimus (L.) Palla in a constructed wetland of the Venice lagoon watershed, Environmental Pollution, vol 144 (3), pp 967-975.

Brix H, Arias C and Johansen NH, 2003.

Experiments in a two-stage constructed wetland system: nitrification capacity and effects of recycling on nitrogen removal.

In: J. Vymazal, Editor, Wetlands: Nutrients, Metals and Mass Cycling, Backhuys Publishers, Leiden, The Netherlands, pp. 237- 258

technical features

~ refereed paper

Davison L, Pont D, Bolton K and Headley T, 2006. Dealing with nitrogen in subtropical Australia: Seven case studies in the diffusion of ecotechnological innovation , Ecological Engineering, vol. 28, pp 213223.

Dirou J, Headley T, Huett D, Stovold G and D avison L, 2003. Constructing a reed bed to treat runoff water - A guide for nurseries. NSW Agriculture, Orange, NSW. Gersberg RM,, Elkins BV and Goldman CR, 1983. Nitrogen removal in artificial wetlands, Water Research, vol. 17 (9), pp 1 009-1014.

Headley T, Dirou J, Huett D, Stovold G and Davison L, 2005. Reed Beds for the Remediation and Recycling of Nursery Runoff Water, Australasian Journal of E nvironmental Management, vol 12, pp 27-36.

Headley TR, Huett DO and Davison, 2002.

Nitrogen and Phosphorus removal from nursery runoff in reed beds, Project Number NY98008, Horticulture Australia Ltd, Sydney.

Huett DO, Morris SG, Smith G and Hunt N, 2005. Nitrogen and phosphorus removal from plant nursery runoff in vegetated and unvegetated subsurface flow wetlands, Water Research, vol. 39, pp 3259-3272.

wastewater treatment Ingersoll TL and Baker LA, 1998. Nitrate removal in wetland micrososms, Water Research, vol. 32 (3), pp 677-684.

Laouali G, Dumont L, Radoux M and Vincent G (1996). General design and performance of reed and emergent hydrophyte beds for domestic wastewater treatment in Quebec, Canada, Proceedings of Fifth International Conference Wetland Systems for Water Pollution Control, /WA and Universitat fur Bodenkultur, Vienna (1996) (Chapter IX/5).

Lantzke IR, Heritage AD, Pistil lo G and Mitchell DS, 1998. Phosphorus removal rates in bucket size planted wetlands with a vertical hydraulic flow, Water Research, vol. 32 (4), pp 1280-1286.

Mander, Teiter S, Lohmus K, Mauring T, Nurk N and Augustin J, 2003. Emission rates of N20 and CH 4 in riparian alder forest and subsurface flow constructed wetland. In: J. Vymazal, Editor, Wetlands: Nutrients, Metals and Mass Cycling, Backhuys Publishers, Leiden, The Netherlands (2003), pp. 259-279.

Perrens Consultants Pty Ltd , 2002. Eden Gardens - Stormwater Re-use and drainage. Chatswood , Australia.

Rolfe C, Yiasoumi W and Keskula E, 2000.

Managing water in plant nurseries, 2nd Edition. NSW Agriculture, Orange, NSW, Australia.

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Seidel, K, 1955. Die Flechtbinse Scirpus lacustris, In: Okologie, Morphologie und Entwicklung, ihre Stellung bei den Volkern und ihre w irtschaftliche Bedeutung. Schwiezerbartische Verlagsbuchnadlung, Stuttgart, Germany, pp. 37-52.

Shaver GR and Melillo JM, 1984.

Nutrient budgets of marsh plants: efficiency concepts and relation to availability, Ecology, vol. 65 (5), pp 1491 -1510 Tanner CC, 1996. Plants for constructed wetland treatment systems - A comparison of the growth and nutrient uptake of eight emergent species.

Ecological Engineering, vol. 7, pp 59-83.

Vymazal J, 1995. Algae and Element Cycling in Wetlands, Lewis Publishers, Boca Raton, Florida.

Vymazal J, 2005. Horizontal sub-surface flow and hybrid constructed wetlands systems for wastewater treatment, Ecological Engineering, vol. 25 (5), pp 478-490.

Wathugala GA, Suzuki T and Kurihara Y, 1987. Removal of Nitrogen, phosphorus and COD from waste water using sand filtration system with Phragmites australis, Water Research, vol. 21 (10), pp 12171244.

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I

REUSE SCHEME BECOMES OPERATIONAL United Utilities Australia has officially co mmissioned a $14m effluent treatment and reuse scheme for the Berri Barmera Council in South Australia's Riverland.

Completion of the project, provided through a Public Private Partnership contract, means that 100% of effluent generated in the towns of Berri and Barmera is now being treated and is available for reuse. This new water supply is providing a much needed new water source in an area that relies heavily on the ever declining River Murray and will help ensure an environmentally sustainable future for the region.

While UUA is the major financier, designer and builder for the project, capital funding was also provided by Constellation Wines which is using the scheme as a disposal and treatment path for winery wastewater and the Berri Barmera Council.

Both the State and Federal Governments also provided contributions to the scheme. Effluent is collected from approximately 4000 septic tank connections and carried to two new treatment plants. An existing treatment facility has also been upgraded to handle wastewater from Constellation Wines' production facilities.

Three new effluent pumping stations along with 32 kilometres of new pipelines and pumping systems for reuse water have also been provided w ith the entire scheme designed to allow for the easy transfer of treated effluent across the network. The scope makes its possible for other potential contributors of wastewater or end users of treated water including industries requiring process water, to join in the future.

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Water Business aims to keep readers alert to business news and new product releases within the water sector. Media releases should be emailed to Brian Rault at brian.rault@halledit.com.au or Tel (03) 8534 5014.

AWA wishes to advise readers that Water Business information is supplied by third parties and as such, AWA is not responsible for the accuracy, or otherwise, of the information submitted.

At this stage the scheme will produce 600 megalitres of Class B standard treated effluent per annum which initially will be mainly used in the irrigation of two golf courses, a large council park and a permanent field days site.

management plan for the Byford Townsite development zone w ithin the Serpentine Jarrahdale Shire district, near Perth in Western Australia. lnfoWorks proved ideal both for its hydraulic modelling capabilities and for its thoroughness in managing data for the many stormwater scenarios that have been explored.

The modelling has been used to establish storage requirements in each catchment to ensure that future developments will not impact downstream environmental assets, explains GHD Waterways Manager, Helen Brookes. It will also ensure that local properties remai n safe from flooding, even in a 100-year event.

A percentage of the reuse water has also been allocated to irrigate crops that can provide economically beneficial returns. Trials have been conducted to assess the viability of irrigating Arunda donax (giant reed) with treated winery wastewater. Arunda donax can be used in paper production and power generation South Australian Minister for Water Security and Local Member for Chaffey, Karlene Maywald officiall y 'switched on' the system during a ceremony at the Berri Golf Course which will henceforth receive irrigation water from the scheme.

For further information contact Stan Boath, Public Relations Manager, United Utilities Australia, Mobile: 0419 698 998, Email: stanboath@uua.com.au

DETERMINING DRAINAGE CRITERIA Consultant GHD has used lnfoWorks CS in the production of a drainage and water

lnfoWorks CS helps GHD determine drainage criteria for Byford townsite in Perth.

GHD has used the results to produce a Drainage & Water Management Plan (DWMP) for Western Australia's Department of Water (DoW). The DoW has an overall statewide responsibi lity for drainage management and is introducing a framework for urban water management, which requi res the production DWMPs for identified areas including Byford Townsite. Local authorities such as Serpentine Jarrahdale Shire are responsible for the ongoing drainage management.

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The DWMP details sub-catchment planning criteria for specific locations in Byford Townsite and has recently been finalised followi ng public consultation. "It covers issues such as where development can take place, what drainage infrastructure needs to be put in place and the environmental assets that developers need to protect," explained Ms Brookes.

GHD's work for the DoW has established water management criteria for each sub-catchment across the whole study area. Every proposed development will require a local water management strategy that addresses the specified issues in line with the report.

Determining the storage volumes and discharges req uired at each subcatchment involved the modelling of many scenarios. This requ ired many different runs and the database system within lnfoWorks CS proved very beneficial in managing the changes that were being made, said Ms Brookes. "lnfoWorks enables you to keep track of what you are doing and leaves an audit trai l," she says.

The chan nels themselves are quite small, but the area is characterised by very broad floodplains and there are extensive overland flow paths. "One of the main features of lnfoWorks that real ly helped us specifically in this study was that we have several different waterways run ning through the site, with a lot of overland interaction between them ," she said.

The modellers also made use of the complex river cross sections that lnfoWorks now enables. "We could model parts of the flood plain, as well as the waterways themselves," she added .

The hydraulic network consists of

interconnect ed nodes - manholes, outfalls and storage basins - and links in the form of weirs, pipes, culverts and open channels.

The lnfoWorks CS model uses a constant infiltration model to generate rainfall runoff and the SWMM single nonlinear reservoir routing model to provide inflows to the hydraulic component. Each sub-catchment in the study area was divided into pervious and impervious areas, with surface roughness, initial losses and infiltration losses applied according to the land use in each place.

The GHD study builds on earlier models carried out in Serpentine Jarrahdale Shire, including a flood study

by SKM which covered the whole river catchment and produced detailed twodimensional modelling of the flood plain.

"An advantage of the new lnfoWorks model is that the hydraulic structures and drain cross sections could be quickly modified and tested in order to develop the appropriate surface water strategies.

"We were able to re-run the lnfoWorks model very easily, changing the sizes and configurations to optimise the storage

new products & services throughout the catchment," she says.

"There were a lot of configurations to test, such as adding culverts and storage, modifying the drains and swapping a river cross section for an open channel drain," she says.

its effluent irrigation scheme, which has conserved potable wat er, achieved high water discharge quality and resulted in savings of several hundred thousand dollars in civil works associated with the scheme.

The project's main contractors, Ted Wilson & Sons, submitted an innovative design for a pressured on-demand irrigation scheme, simplifying the infrastructure and providing the council with a more economical project - as well as red ucing the long term operating cost.

CST Wastewater Solutions (formerly Contra Shear Technology) was awarded the UV disinfection equipment supply contract. The company chose Berson lnLine medium pressure lamp technology that is now fu lly integrated into the counci l's PLC/SCADA process control system.

The fi nalised DWMP enables developers to consider a particular area and determine the indicative storage vol ume t o achieve defined discharge flow rates. Suitable storage might simply involve using a park where there is a grassy area within the floodplain, where water can be held without impacting on people's houses.

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WATER INITIATIVE AT GOULBURN When much of NSW faced drought conditions for more than five years, the inland city of Goulburn became a symbol of the hardships faced by the state as a whole.

The situation in Australia's first inland city attracted national attention as drinking water dam levels plunged, rat epayers halved their water consumption, level five water restrictions were introduced, and the Goulburn Mulwaree Council prepared contingency plans to truck in drinking water if thi ngs didn't get better.

Fortunately, things did get better over the last year, but the counci l has continued with water conservation and water quality initiatives that will stand it in good stead for the future - and perhaps serve as a model for other cities increasingly facing similar issues in the face of global warming. One of Goulburn Mulwaree Council's successful initiatives involves the selection of medium pressure ultraviolet (UV) disinfection for

106 SEPTEMBER 2008 water

Berson UV-techniek is t he world leader in medium pressure UV t echnology and was the first to develop the cross flow in-line system now employed in the Goulburn Mulwaree effluent irrigation scheme.

"The germicidal properties of ultraviolet (UV) light are now well understood and have become widely accepted as a method of wastewater disinfection.

Medium pressure UV technology is relatively new in Australia but is rapidly gaining recogn ition for its advantages" said Pieter Groenewegen, Business Manager of CST Wastewater Solutions.

"Many wastewater treatment plants worldwide are now using UV tech nology, with an increasing emphasis on reuse applications."

According to Greg Finlayson, manager water services, Goulburn Mulwaree Council: "We were already using effluent for irrigation but the UV treated effluent gave the council more opportunities for reuse - as well as improving the quality of water that eventually finds its way into the Wollondilly River, which is part of the Sydney Water catchment. " "The UV disinfection system is achieving a good microbial ki ll rat e and the overall performance of the completed scheme is excellent," said Marina Hollands, water and waste engineer, Goulburn Mulwaree Council.

There are two main types of UV mercury lamps for disinfection. Low pressure monochromatic lamps that have a single wavelength spike of 254 nm, while medium pressure UV is polychromatic with a variety of wavelength spikes. Bot h disinfect, but the medium pressure technology is considered to be superior as it prevents photo-reactivation.

The Goulburn Mulwaree construction contract, completed in 2007, was originally based on a NSW Department of Commerce design that called for pumping from the storage pond through an in-channel low pressure UV disinfectiom system to a secondary 200 cubic metre storage tank, followed by an on-demand pumped irrigation system The alternative Ted Wilson design took an innovative approach, selecting high efficiency submersible pumps, eliminating a new pump wet well, plus eliminating the secondary tank and pumping directly to the irrigation scheme from the storage pond through the Berson UV system as an on-demand irrigation system.

The advantages of this system were: â&#x20AC;˘ Lower capital cost. The single pump station resulted in simpler infrastructure. â&#x20AC;˘ Much simplified const ruction. The storage pond embankment would have required significant reconstruction to fit the new pump wet well and the concrete chan nel for the UV disinfection. The new design used a floating pontoon for the submersed pumps. The medium pressure UV system is in-pipe and has a very compact foot print. â&#x20AC;˘ Lower operating cost. A single pump station uses considerably less operating power and maintenance is simplified. The medium pressure UV system has fewer lamps and is easier

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new products & services to maintain. Everything is accessible above ground with no need for lifting gear.

The scheme's four-chamber UV disinfection system consists of two parallel trains of two chambers in series.

Each chamber contains 12 Berson 3.5 kW medium pressure multi-wave lamps, making a total of 48 lamps. The system is designed to operat e with either one twin train or both together, disinfecting flows of 100-400 litres per second. A low-flow jacking pump system maintains the irrigation system pressure when there is no demand.

CST Wastewater Solutions (formerly Contra Shear Technology) has been providing a broad range of industrial and municipal water and wastewater solutions for 25 years. CST Wastewater Solutions is a member of the Global Water and Energy Alliance, a group of select companies around the work com mitted to providing solutions in waste and wastewater treatment for the recovery of green energy and water.

For further information, contact Michael Bambridge, Managing Director, CST Wastewater Solutions, (02) 9427 1279, email: info@cstechnology.com.au, web: www.cstechnology.com.au

WATER LEAKAGE SOFTWARE ADDRESSES PROBLEM Bentley Systems has released the latest version of its Darwin Calibrator module featuring water-leakage modelling capabilities. The new version of the module, wh ich is included in WaterGEMS V8 XM and available for WaterCAD V8 XM , provides a cost-effective way to estimate the location and extent of hidden leakage in underground pipes.

The Ontario Sewer and Watermain Construction Association in Canada reported that approximately $1 billion worth of clean drinking water disappears into the ground every year from deteriorated and leaky municipal water pipes. The innovative methodology behind the new Darwin Calibrator was developed by Bentley and United Utilities

Water (UUW) PLC, a FTSE-100 company with a turnover of almost $4 billion and a staff of 9,000. UUW supplies water and wastewater services to 7.5 million customers in North West England and provides utility services to around 20 million people via international

businesses spanning Austral ia, Central Europe, and the Philippines.

Commenting on the key benefits of the new Darwin Calibrator technology, Dr Zheng Yi Wu, Bentley's director of applied research in engineering optimisation, said, "Existing leak-

C&SBRAND AUSTRALIAN FILTER COAL FOR DEEP BED COARSE DUAL MEDIA FILTRATION "More UFRVs for your money, and better quality water"

C&S BRAND GRANULAR & POWDERED ACTNATED CARBONS JAMES CUMMING & SONS PTY LTD 319 Parramatta Rd AUBURN NSW 2 144 Phone: (02) 9748 2309 Fax: (02) 9648 4887 Email: jamescumming@jamescumming.com.au

QUALITY ENDORSED COMPANY AS/NZS ISO 9001 STANDARDS AUSTRALIA Licence no: 1628

water SEPTEMBER 2008 107

new products & services a number of indirect starting methods that can be implemented including a star-delta starter, auto transformer and a soft starter. Variable Speed Drive (VSD) also helps t o minimise the starting load demand as does changing the motor speed.

An upgrade to a wastewater treatment plant can provide real benefits in the form of: • Reliable supply of recycled water • Supply of renewable resource • Improved Workplace Health & Safety

Starting each load in sequence with only a few seconds in between each load step reduces the generators capacity. In addition, it also allows turbocharged engines to gradually take up the fu ll load.

Turbocharged engines only accommodate about 60-70% of the rated capacity in one step. Some manufacturers claim that a 100% step load is possible, however the excess speed drop during the step load makes this feature ineffective.

• Reduction in greenhouse gas emissions • Odour reduction Contact Grant Cobbin on (07) 3279 3276, email grantc@epco.com.au, web www.epco.com.au.

STANDBY POWER FOR TREATMENT AND RECYCLING PLANTS Although most water treatment plants have mains power supply, standby generators are widely used to provide backup power during failure of normal power. When choosing a standby generator, electrical engineers and plant managers should always assess the details of each piece of equipment and the load that will be connected to the generator. In particular, they should consider the requi red starting load and harmonic content.

Mechanical engineers and plant managers should also be aware that some motors, such as those attached to conveyor belts and vibration screens, wil l start on load. Motors attached to these types of applications require considerably more power when compared to the same motor driving a pump, blower or air compressor.

Calculating the required load of the standby generator can be done manually. However reputable generator manufacturers such as Kohler and SOMO provide sophisticated software to help simplify such calculations.

It is important to choose a standby generator with a capacity (rated at 0.8PF by international standards) that is greater than the total load in both KW (real power) and KVA (apparent power). Unlike normal mains power, a standby generator cannot support any overload above the standby power even for a few seconds.

When selecting a standby generator, mechanical engineers and plant managers should also consider harmonic cont ent. High harmonic content causes the mot or to overheat and lighting flashing. It also affects the normal operation of the automatic volt age regu lator (AVA) of the generator, often causing it to fail. The harmonic voltage should be kept

All motors draw from five to eight times more current when starting directly. Therefore, the capacity of the standby generat or should be able to accommodate the starting overload. To reduce the amount of overload there are

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below 10% but most AVRs are able accommodate up to 15%.

Although generators with a low subtransient reactance (X"d), such as 12%, will help reduce the harmonic voltage, those lower than a 10% subtransient reactance are usually oversized and uneconomic. All VSD and UPS manufacturers offer power supply harmonic filters. Some also provide active harmonic treatment to guarantee that the power supply harmonic is less than 5%. This is always more economic than oversizing the generator alone.

For more information on standby generators contact Compressed Air and Power Systems (CAPS Australia) on 1300 858 763, www.capsaustralia.com.au or email info@capsaust.com.au

WIDE RANGE OF USES FOR SHAFTLESS SCREWS Wilcox Engineering and Conveyors are able to provide a wide range of products in full turn key or raw shaftless screw only options and pride themselves on their prompt and efficient before and after sale service. As their WILCON products are manufactured in Queensland, they are an affordable alternative to the imported range.

Shaftless screws can be used in a range of industries that require efficient and low maintenance mat erial handling solutions for wet, sticky, fibrous or bulky material as they have no intermediate bearing, only end bearing and low RPM means less power usage.

Their shaftless screws are in use throughout various industries including municipal sewerage, wastewater treatment plants, mining, paper mills, vegetable processing (carrots and onions), abattoirs and hazardous medical waste.

Shaftless screws come in a range of pitches and sizes with both left hand and right hand screws available. They can be manufactured from Bisalloy or Carbon Steel. Double screws for deeper flight width are also available in some sizes.

For more information see www.wilcoxeng.com.au

110 SEPTEMBER 2008 water

water business

new products & services USEFUL FEATURES FOR SMART ACTUATOR Introduced to the flow control marketplace in 1997 as the first smart actuator that provided uncompromising reliability, performance and ease-of-use, the newest Limitorque MX has been redesigned to provide users with a longer operational life.

Available for use on a wider variety and size of 360-degree, multi-turn valves than ever before, the globally certified device meets most world utilisation standards. Key improvements to the MX include a patented absolute encoder with increased span, improved diagnostics capability, and built-in self-test (BIST).

The Limitorque MX is also double-sealed, allowing for containment of any leakage within the t erminal compartment.

One of the operational advancements in t he Limitorq ue MX has been enhancement to the special absolute encoder. The 'smart' and flexible encoder config uration helps simplify valve automation through configuration/ setup, normal operat ions, diagnostics, and troubleshooting. Another enhancement to the newest encoder model is that the drive sleeve turns have significantly increased. Whi le the initial MX model had a span of 1,340, the Limitorque MX has now been improved to allow for a span of over 10,000 turn options.

The Frequency Domain Analysis (FDA) featu res of the unit capture torque, position and speed values at regular time intervals. While monitori ng these events,

the resulting data set is automatically calculated to pinpoint the fail ure or failed components. Failed or failing components can thus be easily targeted, and the data monitored , in any type of use in order to determine and report faults. And the MX can retain this positioning without the need for an auxiliary power backup.

Unique to the market are the built-in, self-tests (BIST) of the Limitorque MX. The BIST feature is designed into a state-of-the-art controls platform that verifies and validates the integrity of its components, a design that aids companies in meeting the Safety Integrity Level (SIL) requ irements of IEC 61508.

A series of parallel optical device transmitters are utilised in the absolute encoder to supply redundant support.

This significant improvement now permits a fault tolerance of up to 50 per cent before the position is incorrectly reported , allowing the device to contin ue to reliably function until a number of faults have been accumulated.

Limitorque MX actuators are available for torques up to 1700 ft-lb (2307 N m) and thrust ratings up to 75,000 lb (333 kN). The units are also powder coated in a polyester resin to protect all components in even the most extreme and harsh environments. Bluetooth wireless connectivity is optional, offering a range up to 10 metres. When used with Limitorque Dashboard™ Windows®based software, diagnostic information is easily transferred to a Wi ndows® Mobileequipped PDA, laptop computer or cell phone.

For more information, contact Ph +613 8727 7800, Fax +613 9729 8699 or www.acrodyne.com.au

ULTRAFILTRATION PLANT COMMISSIONED CRS Industrial Water Treatment Systems Pty Ltd has recently completed commissioni ng of a 4 MLD Ultrafiltration (UF) surface water treatment plant for WA Water Corporation. The UF system was incorporated into the overall water

treatment plant for the town of Denmark in the South Western region of WA. The system was designed and manufactured using Norit Xiga™ UF membranes, providing guaranteed log removal rates of 4 and 6 for viruses and bacteria respectively. This guarantee is ensured through daily automatic membrane integrity testing. A previously supplied containerised 500m 3/ day Norit UF system is used for the treatment of backwash water to increase overall system recovery to - 99%.

Electrical panels include Koyo 10"colour HMI touch screens, ABB variable speed drives and Koyo Direct Logic 405 PLCs. Siemens pressure transmitters and magflow meters were used along with Hach turbidity monitors.

Remote feed pump operation is controlled via fibre optic commu nications and the overall system is monitored on the site SCADA system.

The feed water is pre-dosed via the suction line to the feed pump with ACH to ensure a suitable microfloc is formed prior to the membranes.

The system incorporates PLC controlled periodic Chemically Enhanced Backwashes (CEBs) using hydrochloric acid, caustic and sodi um hypochlorite that are dosed during backwash followed by a short soaking period. The CEB waste stream is captured and neutralised prior to thickening and dewatering using a geotextile dewatering bag. Regular CEBs ensure that there is no need for a manual clean in place system and as such the entire membrane clean ing process is fu lly automated by the PLC control system.

CRS are currently constructing 2 x 500m3/ day containerised Reverse Osmosis (RO) plants to treat a sidestream of the UF fi ltrate to bring it within Australian Drinking Water Guidelines for TDS during seasonal increases in raw water salinity.

For more information (02) 9899 7811, web www.watertreatment.net. au

• • • • • • •

GEORG FISCHER PIPING SYSTEMS

Ph: 07 3390 7166 Fax: 07 3390 7177 Email: info@allflowsupply.com.au

Web: www.allflowsupply.com.au

Automation Data Logging Pressure Control PH / ORP Flow Meters Plastic Piping Systems Automated Meter Reading Equipment • Under Pressure Tapping Equipment

water SEPTEMBER 2008 11 1

new products & services facilitated the development and custom designed features of th is type of infrastructure.

incorporating the decant design ensures the gate lifts straight up with a dual spindle to meet best practice procedure for wider flow control gates utilised within the industry. Accurate and site specific installation is another key element of any successful flow control infrastructure. AWMA is the only company in Australia who directly employee a dedicated installation team, available Australia-wide.

Tel AWMA on 1800 664 852, website: www.awma.au.com

AWMA has made significant advancements on the traditional decant gate design. The design for AWMA's Downward Opening Penstock provides a downward opening mechanism with an on and off-seating seal arrangement for an exceptional water-tight seal when ful ly closed. AWMA's Downward Opening Penstock may be manufactured from marine grade aluminium or stainless steel and can be operated via manual, automated or SCADA connected actuation systems.

AWMA's Downward Opening Penstock was custom designed for recent works at Melbourne Water's Eastern Treatment Plant (ETP). Among other significant works underway at ETP, the AWMA gate upgrades contribute toward Melbourne Water's commitment to continually improving ETP's environmental performance.

The Downward Opening Penstock was selected for this project for both its operational benefits and its customised features. Manufacturing a product

IMPROVING WATER QUALITY BY BIOLOGICAL TREATMENT In many regions of Australia, water supplies are under pressure from decreasing raw water quality due to urbanisation of their catchments, drought and changing land use. Potential alternative water sources such as stormwater harvesting tend to have a lower quality than traditional sources. At the same time, higher community expectations of town water supplies are creating pressure for improved water quality.

There are many biological, inorganic and organic contaminants that can affect the safety and aesthetic quality of water supplies. Disinfection of water and the chemistry and treatment of inorganic substances is relatively wel l understood.

On the other hand, the wide range of organic compounds that can be present in water, their diverse properties and site specificity makes the removal of organic matter from water a complex task.

There is a need for sustainable treatment t echnology that is capable of

removing a broad range of organic compounds from water. The technology should be readily available, robust, effective and have a low energy usage.

Biological water treatment has t he potential to meet these criteria if it is optimised for removal of organic compou nds. However, there has been little work done on optimising biological treatment processes for the removal of general organic compounds to produce a biologically and chemically stable water supply.

To investigate the application of biological treatment to water the CRC for Water Quality and Treatment sponsors an Ecowise project focused on optimising parameters in constructed biological treatment units. The aim is to use the known ability of bacterial biofilms and fungi to utilise these compounds in a controlled and optimal environment, thereby achieving maximum biological treatment to complement and improve existing physico-chemical processes.

The project, which has been runn ing for the last two years, has demonstrated that the use of biological filters is a viable technology for removing DOC to produce biologically stable water with red uced potential for bio-fouling of pipes and fittings. The treated water has fewer organic compou nds to act as precursors for disinfection by-product formation. As a result, the use of biological treatment processes with high DOC removal has the potential for improved outcomes where: • Beneficial reuse of water is required for high-level uses • Reuse water is transported over long distances or stored for extended periods

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• Disinfectant demand in water is high and residual disinfection is short lived

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• Disinfection by-products are of concern DfTAltl

• Treated waste water is discharged into highly sensitive receiving waters.

For more information, contact Ecowise Environmental Principal Consultant, Chris Pipe-Martin, on (07) 3859 7806 or at cpipe-martin@ecowise.com.au

BEGA VALLEY SEWERAGE PROGRAM COMPLETED

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DOOR CLOSED

114 SEPTEMBER 2008 water

SfCTtON H-H

A ceremo ny to officially mark the completion of the Bega Valley Sewerage Program (BVSP) was held on September 1 at the Bega Sewerage Treatment Plant, one of the new treatment plants built

water business

The program which started in 2003 was delivered through the alliance of Ten ix Alliance and the Bega Valley Shire Council.

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Together, the Alliance developed sewerage facilities in the Bega Valley, an area of 7000 square kilometres in the south-eastern corner of New South Wales with a population of 30,000.

Key objectives were to design, construct and com mission new sewerage schemes (including treatment plants and networks) for Cobargo, Candelo, Woluma, Kalaru and Wallaga Lake Vi llages; and upgrade five Sewage Treatment Plants at Bermagui, Bega, Tathra, Merimbula and Tu ra Beach to overcome Environmental and Public Health Problems and create recycled water reuse opportunities.

"Our involvement in the BVSP is something we wi ll always be proud of. Tenix Al liance has maintained a close relationship with the Bega Valley Shire Council throughout the program and together we have delivered a truly world class project", says Sean Woellner, Chief Operations Officer of Tenix Alliance.

Dulcomarin II Multiple Pool Control pH, ORP, Chlorine (free & total), Temperature, Conductivity Embedded Web Server for Connection to Internet Inbuilt Screen Recorder Remote Access for Control & Logging CANBUS Technology D2C Single Channel Bi-directional Output Pulse, mA or Actuator Control Proportional or PIO DMT Measuring Transmitters pH, ORP, Cond, Chlorine, Temp.

Intelligent 2 wired device 4-20mA isolated Output

SENSORS

Th e BVSP received a commendation at the 2006 Engineering Excellence awards for Regional Communities for delivering innovation in the engineering of wastewater solutions in rural communities in three key areas of technology, contracting, and commercial performance.

Technologically, the BVSP utilised an innovative solution, combining a pressure sewerage system and a membrane bio-reactor wastewater treatment plant; and horizontal directional drill ing as the main method of installing the pressure sewage mains.

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Chlorine (Free & Total) pH ORP Temperature Conductivity Chlorite

Hydrogen Peroxide Peracetic Acid Ozone Bromine Chlorine Dioxide Dissolved Oxygen

DOSING PUMPS

Contractually, the BVSP is the first time that an alliance framework has been employed to undertake a program of works for a NSW local water utility and is the first alliance for a NSW local water utility that has awarded a contract including an extended period of operations.

Commercially, the BVSP was delivered below the NSW public sector benchmark for conventional regional sewerage schemes, a win for the people of Bega Valley.

Th is success story has been instrumental in improving the health and environment for the Bega Valley communities. It has made significant enhancements to the method of treating wastewater, enabling water conservation through re-use on public facil ities and wil l ensure cleaner local waterways.

Tenix Alliance wi ll be operating the five water treatment plant s for the next ten years with an optional extension.

For more information: Malou Atayde, Communications Manager - Tenix Alliance, 0447 228 967.

Sigma

Gamma L

Beta

Precise Metering Relief/Priming Valve Auto De-Gassing Pulse and mA Control CANBUS and PROFIBUS Control Available in PP, PVC, PVDF, SS

www.prominentfluid.com.au

water SEPTEMBER 2008 115

advertisers' index MEMBER OF

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ADVERTISERS' INDEX ABB

51

Ecowise Environmental

77

Norma Pacific

ABS Wastewater Technology

19

Epco Australia

88

Orica Watercare

31

Acacia Filtration Systems

99

esam

Orrcon

11

Aerodyne

41

Flowserve

87

Ozmotech

35

Allflow Supply Co

18

Gale Pacific

57

Permastore

34

Allflow Supply Co

111

Plasson

33

27

Gentrack

101

9

8

Australian Pollution Engineering 45

Global Synthetics

73

PPI Corporation

AWMA Water Control

Grundfos

13

Projex Group

103

Hanna Instruments

32

ProMinent

115

7

Solutions

AWMA Water Control

Hatch

6

113

Solutions

International Protective Bentley Systems, Inc

69

SKM

61

Coatings

47

Tenix

15

ITT

21

Tyco Flow Control

39

107

Tyco Flow Control

43

inside front cover

Bentley Systems, Inc

Redox

104 James Cumming & Sons

56

Black & Veatch

John Morris Scientific

59

Tyco Water

25

Johnson Screens

68

Veolia Water

78

KASA Redberg

48

Vinidex Systems & Solutions

29

Koch Membrane Systems

53

Vinidex Systems & Solutions

KSB Australia

23

Brown Bros Engineers

109

Australia BTO

83

103

By-Jas Engineering CAPS Australia

14

CitectSCADA

17

Clexan-Peak Personnel

95 116

Copon Pipelinings CRS Industrial Water

Mace

105

Merck

46

MWH

3

MWH

28

Treatment Systems

97

Noblewater Industries

74

Danfoss

55

Norit X-Flow

63

116 SEPTEMBER 2008

water

inside back cover

Viridis Consultants

79

Wallingford Software outside back cover

Water Technology Australia

96

Waterco

36

Wilcox Engineering and Conveyors

w t

100

lnfoWorks RS surface flood modelling

With the increasing frequency of extreme flood events, managing the flow of water in rivers and coastal floodplain areas has never been more important. lnfoWorks RS is an advanced modelling tool that combines 1D simulation bf flows in rivers and channels with 2D simulation of surface flood modelling in the floodplain and urban environment.

Works MRS 1

lnfoWorks RS geographical and sectional views

• •

• • • lnfoWorks 2D animated maps of depths & velocities •

Full solution modelling of open channels, floodplains, embankments and hydraulic structures Fully integrated breach modelling for homogeneous and composite embankments and dams through overtopping, piping or surface protection failure Rainfall-runoff simulation using both event based and conceptual hydrological methods .

Interactive geographical plan views, 3D views, sectional Views, long profiles, spreadsheet and time varying graphical data Animated presentation of results and analysis using maps, tables and graphs Full flood-mapping capability based on a sophisticated flooc!interpolation model overlaid onto an imported ground model

~ nj lnfoWorks RS dynamic breach modelling

Works'" 2D

• Ideal for modelling flows over large rural areas and complex urban environments • Accurate and effective modelling of flows through streets, around buildings and over open ground • 2D elements fully integrated within the 1D network • Includes tools for the creation of 2D meshes and fully animated maps of flood depths and velocities

"By using 1D simulation to identify where flooding happens, and then using the combined 1D and 2D simulation to investigate the direction and depth of flood flows in these smaller areas, users can achieve a cost-effective balance between model-building time and simulation accuracy."

l11 f0Work<. is a registerl'd t ra d ema rk of Walli 11gford So ftw,ire Lirn itl'd

Wa llingford Software Ltd Wallingford Software Pty Ltd, Leve l 20, Darli ng Park Tower. 2, 201 Sussex Street, Syd ney, NSW 2000 Telephone: 02 9006 1603 Ema il: sa les@wa llin1gfo rdsoftware.com

www.wallingfordsoftware.com