__MAIN_TEXT__

Page 1

Volume 37 No 6

SEPTEMBER 2010

AWA JOURNAL OF THE AUSTRALIAN WATER ASSOCIATION


w at er

Journal of the Australian Water Association ISSN 0310-0367

Volume 37 No 6 September 2010

contents REGULAR FEATURES From the AWA Chief Executive What Does the Future Hold? T Mollenkopf 4 My Point of View

5

S Burn

Crosscurrent

8

R Knee

Aquaphemera

8

Industry News

14

AWA News

18

AWA Annual General Meeting

24 30

Events Calendar Enviro 10 - see page 16

FEATURE REPORTS Protecting Our Catchments

M Bartley, A Skipper

32

A Standard Framework for Catchment Condition Reporting J Gourley, Senior Consultant, ALS Water Resources Group

34

Environmental Water Allocation: Some Unresolved Issues Dr J J Pigram, Adjunct Professor, University of New England

40

WA 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

I

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, April, May, June, August, September, November and December. EDITORIAL BOARD Chair: Frank R Bishop; Dr Bruce Anderson, AECOM; Dr Terry Anderson, Consultant SEWL; Michael Chapman, GHD; Robert Ford, Central Highlands Water (rtd); Anthony Gibson, Ecowise; Dr Brian Labza, Vic Health; Dr Robbert van Oorschot, GHD; John Poon, CH2M Hill; David Power, BECA Consultants; Professor Felicity Roddick, RMIT University; Dr Ashok Sharma, CSIRO; and EA (Bob) Swinton, Technical Editor.

AWA

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

Water Quality Monitoring and Analysis Roadshow - see page 22

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 principal 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 Helen Kelton, 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 Raul!, 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

OUR COVER 'Pigging' is a well tried method of cleaning water mains of all sizes, even t he large diameter mains used in the South East Queensland water grid. Our photo shows the lowering of a 962mm diameter polyurethane foam pig into the purpose-built permanent pigging facility at Stayplton Balance Tank, where it ran some 15 km to Coomera permanent online Pigging Launch and Receiving pit. The discharge of precommissioned water in front of the pig would have been in the range of 15 megalitres followed by 1 megalitre of flushing water. Planning for the disposal of such flows into the environment, whether urban or country, has both social and legal aspects which are discussed on page 84.

water

SEPTEMBER 2010 1


wat er

Joumal ofthe A,straHa" Water Association ISSN 0310-0367

Decentralised Development: The Ecovillage at Currumbin - see page 58

Volume 37 No 6 September 2010

contents

Multi-criteria Sustainablity Analysis for the Margaret River Project - see page 73

TECHNICAL FEATURES ([B] INDICATES THE PAPER HAS BEEN REFEREED) WASTEWATER TREATMENT

[i]

Pathogen Removal by a Membrane Bioreactor

Excellent results throughout five year's operation

L Pettigrew, M Angles, N Nelson

44

Evidenced-based approach to recycled water safety for groundwater replenishment K Linge, P Blair, F Busetti, C Rodriguez, M Handyside, J Blythe, M Bromley, OLord, S Higginson, A Heitz, C Joli, C Newby, S Toze

52

[i]

Validation of Dual Membrane Treatment for Indirect Potable Reuse

SUSTAINABILITY DESIGN FOR URBAN WATER

[ii

Decentralised Development: The Ecovillage at Currumbin

The energy and water balances have been monitored and found to be almost neutral B Hood, E Gardner, R Barton, R Gardiner, C Beal, R Hyde, C Walton

[i]

Sustainability Comparison of Third-Pipe and Seawater Desalination Systems in Western Australia

Third pipe systems perform well against desalination

[I]

58

M Anda, N Hodgson, S Dallas

67

DVisser, K Edwards, M Hunt

73

GSeil, 0 Zhang

79

M McAlpine, M Breitfuss

84

W Ahmed, S Toze, T Gardner

89

AR Ladson, KA Austin

94

Multi-criteria Sustainablity Analysis for the Margaret River Project

The lowest cost design is not the optimal solution ENVIRONMENTAL WATER MANAGEMENT

[I]

CFD Modelling of Desalination Plant Brine Discharge Systems

Physical and numerical modelling of brine plume dispersion

[i]

Discharge of Water to the Environment from Potable Water Infrastructure

Planning to satisfy legal and duty of care obligations

Ii]

Faecal Source Tracking in SEQ: Case Studies

Current FST tools can be successfully applied WATER INDUSTRY CAPACITY DEVELOPMENT

[I]

Skills Shortage in the Water Industry

Strategies are being developed WATER BUSINESS

New Products and Business Information. Special Feature: Wastewater Treatment

102

Advertisers' Index

112

2 SEPTEMBER 2010

water


awa news Eco Guardians Pty Ltd Garland Hawthorn Brahe

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

Corporate Bronze

Corporate Gold Burkert Fluid Control Systems

Rotech Water Fortescue Metals Group Ltd

Corporate Silver Sika Australia Pty ltd

Corporate Silver

Overseas

Downer

Pump Systems Ltd - New Zealand

NS W C. Monte, J. Cen, Y. Zhu, K. Phetsaya, R. Barnes

Corporate Bronze

Corporate Bronze

RMP Abrasive Blasting Enware Australia Pty ltd Merriman Controls Eurobodalla Shire Council OLD

Farra Stainless - New Zealand

OLD B. Gaylord, B. Taylor, D. Berry SA G. Dharmasena, L. Macadam

ACT R. Ogden NSW D. Pont, M. Saunders, J. Gray, Y. Gokhale, J.

VIC

Kennedy, T. Egan, D. Bryant, C. Waterhouse, C. Hoey, A. Mclean, J. Ellis, S. Sivabalakan, C. Moloney, C. Gassman, P. Degnan, A. Deen, H. van Rhijn, D. Taylor, S. Zikovski, S. Krishnamurthy, S. Yorkston, S. Alam, J. Walsh, C. Young, S. Yorkston, R. Scott, S. Ong, Y. Shi NT K. Green OLD R. Tolley, J. Hunter, B. Edwards, D. Drapper, T. Frost, R. Strom, B. Irwin, B. Walls, R. Dryden, A. Brown, T. O'Neill, C. Teske, M. Porter, I. Canham, J. John, N. Graf, R. Pickering, G. Djordjewitsch, J. Postlethwaite, B. Thorsteinsson, Y. Hughes, G. Brown, G. Adams, J. Robinson

Corporate Bronze

SA S. Nettle, B. Hill, C. Gordon, J. Voortman, S. Haures,

The Water and Carbon Group Corporate Silver

Humes Heggies Pty ltd Corporate Bronze

Harvest Water Management Consultants Pty ltd SA Corporate Bronze

Australian Publishing Resource Service

Wastewater Aeration & Pump Systems Australia CNAPSA) Pty Ltd JHL Civil Ply Ltd

Partner ,-,,.

>vtrnnMnt

~th Au1tr1ll1

Corporate Silver

Keppel Prince Engineering Global Pipe Australia WA

NSW

Corporate Gold

~~"'v ; •""

Rose, M. Majeed, M. Cole, V. Cail, K. Choong Quah, D. Wilson, D. Kirby, H. Sheffield, C. Langcake, D. Porat, P. Williams, A. Stacpoole, A. Brault, A. Holman, A. Tourney, T. Ibrahim, R. McDonnell, A. Nyholm, K. Shah WA D. Brown, P. Calneggia, M. De Lacey, G. Kerlin, C. Annison, L. Hughes, A. Richard, C. Boehl, P. Fitton, A. Vincent, B. Agarwalla, J. Petersen Overseas R. Genever, Y. Na Eeo, I. McEwen, M. Cloutier

CsAWater

E. Rossi VIC D. Steedman, A. Grieve, M. Nelson, M. Van Enk, P. Vimpani, H. Jackson, C. Chiam, P. Davis, R. Lane, D.

Principal Sponsors

t:qca

Wai%

c<<

~

WSAA W.t.Tll SU'IICU AUO<IAflOlol

ACT A.McRorie NT M. Edwards, A. Sheehan OLD Radbourne, F. Milnes, N. Broom SA MacGillivray, B. Gay, T. Qiu, C. McCallum, B. Ibbotson, S. Lasslett TAS M. Barrenger VIC L. Sibly, M. Hardy, B. Santosi, A. Emmerson, W. Gielewski, F. Boodhna WA S. Bouchard, A. Buckeridge

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.

Presented by

Gala Dinner Sponsor

(!, United Utilities AU

,q,,.

PARSONS P, ,a BRINCKERHOFF

AWA

IA

AUSTRALIA ' S NATIONAL WATER CONFERENCE AND EXHIBITION


feature article

Protecting Our Catchments Water Authorities Need to Remain Vigilant Mark Bartley and Alice Skipper Many urban populations, whether in regional centres or metropolitan areas, are dependent upon water supplies from open catchments. These catchments may accommodate intensive agriculture, rural residential subdivisions, industrial and other land use activities. Often t hese areas are subject to control by catchment management and water aut horities as well as local governments administering planning controls. An issue wh ich has arisen in a number of states is a regulatory 'hiatus' between water authorities, which are ultimately responsible for potable water quality, catchment management authorities responsible for administering strategies over their catchments and local governments acting as planning bod ies responsible for the grant or refusal of plannin g approvals for land use and development.

These issues were recently brought to the fore in a Victorian Supreme Court case, Western Water v Rozen & Anor [2008] VSC 382, where Western Region Water Corporat ion challenged a decision of the Victorian Civil & Administ rative Tribunal (VCAT} to grant a planning permit for a dwelling relyi ng on onsite wastewater treatment and disposal in an open pot able wat er supply catchment area. The case was supported by Central Highlands Region Water Corporat ion which had a parallel proceeding in another matter on similar grounds. The case turned on the interpretat ion of the precautionary principle. Osborn J overturned the initial VCAT decision, which had taken the position that a risk of irreversible envi ronmental damage was necessary to invoke t he principle, and that the rigorous application of the Septic Tank Code of Practice, Minist erial

Experience the difference Monadelphous is a leading nat ional engineering group providing engineering construction, maintenance and industrial services and electrical and instrumentation services to the resources, energy and infrastructure sectors. As principal contractors in construction of major water infrastructure, we have earned a strong reputation for:

..

.

]. it:!· 7, ' I - 1

• Delivering innovative, high-quality solutions • Providing reliable and flexible services • Developing strong customer relationships by delivering on our promises. Our capabilities extend across the lifecycle of water infrastructure, from concept design and construction to the commissioning and operation of water facilities. To make your next water project a success, consider Monadelphous.

II Monadelphous Email: monadelwater@monadel.com.au

32

Perth (Head Office):

Brisbane:

Tel: (08) 9316 1255

Tel: (07) 3368 6700

SEPTEMBER 2010

water

www.monadelphous.com.au

Guidelines and the planning scheme provisions should provide t he appropriate level of safety consistent with the expectations of the precautionary principle. Osborn J disagreed, stating that " ...the Tribunal has arrived at certainty without first considering properly or at all the doubts necessarily raised by the provisions of t he Guidelines and the planning scheme, whether despite the provision of a land capability assessment, septic tank system compliant with the Code and setbacks exceeding those envisaged by the Code, the proposed dwellings will give rise to an unaccept able cumulative risk of pollution of potable waters." It was ultimately found that it was sufficient to justify a refusal based on the precautionary principle t hat there was a risk of serious or irreversible environmental damage. Th is case highlights t he need for water authorities across Australia to be vigilant, in relation to t he act ivities of local governments exercising plan ning powers, particularly in areas outside their district or region where they may not have any particular statutory role (for example, as a referral authority or service authority). This includes situat ions where upstream catchments are under the management of a catchment management or other authority. The case also highlights the need for reform of governance arrangements in the sector. The rather crude application of the COAG principles of separating resource management from retail service delivery has produced a situation where the resource manager has no direct accountability for managing risks to the resource where the outcome of that risk management is felt-and paid for-by a downstream community and riot by the catchment management authority or t he local government exercising planning approvals. Mark Bartley & Alice Skipper Partner and Senior Associate DLA Phillips Fox Mark Bartley is a Director of AWA See also ' Drinking Water Protection: A Victorian Supreme Court Decision', A Davison, A., et al., Water, August 2010.

feature articles


PIPING&-B fAUTOMATION SYSTEMS SUPPLIERS OF INDUSTRIAL PLASTICS Pipe, Valves and Fittings A A A A

A A

Grey PVC-U Sch80 and Metric C-PVC Sch80 ABS Polypropylene PVDF Polyethylene

Instrumentation +GF+ SIGNET A A A A A

A

Flow - Mag , Turbing & Paddle PH ORP Conductivity Resistivity Turbidity

Jointing Technology and Accessories A A A

A

Solvent Cement Socket Fusion Electro Fusion IR Welding

A Oakleigh South 4 Jacks Rd, Oakleigh South VIC 3167 Ph : 03 9563 7666 Fax: 03 9563 7722

A Laverton North Factory 6 /3-5 Weddel Court, Laverton North VIC 3026 Ph: 03 8360 8944 Fax: 03 8360 8573

Email: sales@paas.com .au

Website: www.paas.com.au


feature article

A Standard Framework for Catchment Condition Reporting James Gourley, Senior Consultant, ALS Water Resources Group Catchment condition reports have an important role in the management of catchme nts, enabling water authorities to gain a greater understanding of how catchments are utilised.

having a background in environmental management, catchment hydrology and water quality improvement projects for Government Departments and Urban Water Authorities.

Typically, catchment condition reports are drawn from those published by government agencies which focus on natural resou rce outcomes rather t han drinking water outcomes, and so can be of limited use to a water authority. In addition , there is a wide variat ion in such reports, not on ly between States, but also between regions due to the wide range of cat chments and sources.

The first stage of this project was a review of literature on catchment condition and other environmental reports from across Australia and other parts of the world , in order to establish a 'master list' of parameters (and t heir presentation style).

This inconsistent approach to catchment cond ition reporting may mean that risks to water sources within poorly managed c atchments remain un-identified across Aust ralia, and conversely, catchment areas which have low risks associated with drinking water quality are not adequately preserved. To address t hese issues, ALS Water Resources Group recently embarked on an investigation for ACTEW Corporation's Applied Research and Development Program to establish a standard approach to undertaking catchment condition assessments. The author undertook t he project

34 SEPTEMBER 2010 water

Using this master list as a prompt, 11 water authorities and one public health authority from across Aust ralia were surveyed to determine their preferences in relation to condition reporting , such as their preferred target audience and frequency of reporting. Respondents were also asked to rank the parameters from the master list as if they were selecting parameters for their own catchment condition report on drinking water quality. The ranking of each parameter could be one of three selections: 'A - Priority' , 'B - Secondary' and 'C - Low or No Interest'. From all the respondents' results, the most popular choice of category for each parameter was determined and assigned to

feature articles


feature article that parameter. For example, if 7 out of 12 respondents chose turbidity to be an 'A' parameter, 3 chose it to be 'B' and 2 chose 'C' then by majority, turbidity was designated to be an 'A - Priority' parameter.

audience) were 'catchment stakeholders' followed by 'senior management of a water authority'. Results of the survey for designation of parameter importance are shown in the following tables:

Survey Results

• Table 1 for water quality parameters

It was apparent, from the results of the survey, that a number of authorities are already developing or have completed a catchment condition report for drinking water quality.

• Table 2 for water quantity and water way parameters

Of the 12 respondents surveyed, 83 per cent indicated t hat a catchment cond ition report specifically targeted to drinking wat er management would be helpful. All respondents indicated that a catchment condition report could potentially influence catchment management outcomes.

• Table 4 for comm unity, social and other parameters.

• Table 3 for land parameters

The preferred frequency of reporting was equally spread, rang ing from 1, 2, 3 and every 5 years. The report could also be produced after a major event that alters the catchment (e.g. a bushfire) in order to quantify changes and risk to drinking water sources. The preferred target audience for a cat chment condition report (survey respondents could choose more than one target

A number of respondents commented that t he master list did not cover recreational use and this factor should be added to the community paramet ers. Responses from the survey provide a guideline for a framework of catchment cond ition reporting for drinking water quality. A range of parameters for water quality and quantity, waterway, land, comm unity and social factors was shown to be important to the majority of survey respondents. However, each individual catchment and authority had a unique set of parameters and issues to address for optimal reporting and drinking water risk management.

Table 1. Survey responses - water quality parameters. Parameter Group

Parameter Importance A - Priority

B - Secondary

Standard parameters

Turbidity, pH, temperature, dissolved oxygen, Ca, Na, Cl, K, Mg, HC03, F, S, heavy colour, biological oxygen demand, organic metals, hardness carbon, N, P, electrical conductivity

Bacterial pathogens

E. coli, total coliforms

Protozoa

Cryptosporidium, Giardia, Naegleria fowleri

Viruses Helminths Cyanobacteria

Salmonella

C- Low/ None

Heterotrophic Plate Count, Campylobacter, Shigel/a, Vibrio cholera, Yersinia

Acanthamoeba Adenovlrus, Enterovirus, Norwalk viruses, Rotavirus

Hepatitis viruses

Helminths Cyanobacteria I microcystins

Algae and toxins

Cylindrospermopsis / cylindrospermopsin, anabaena I saxitoxins

Pesticides

Atrazine, a broad suite of pesticides

Nodularia / Nodularin

Silica Aldrin, Deldrin, DDT

Other Endocrine Disruptors

Volatile organics (e.g. BTEX, MAH, THM)

Radioactivity

Radioactivity

Hormones, Semi-volatile organics (e.g. PCBs)

Table 2. Survey responses -water quantity and waterway parameters. Parameter Group

Parameter Importance A - Priority

B - Secondary

C- Low/ None

Water Quantity Waterway

Streamflow, bulk water extractions, environmental flows, groundwater resources

Climate

Rainfall, evaporation

Waterway Riparian zones

Riparian zone condition, vegetation cover, width, location and length of fencing for livestock exclusion

Macroinvertebrates

Proportion of native and exotic vegetation, aquatic fragmentation Species / abundance, Ausrivas score

Fish/ fauna

Species / abundance

Geomorphology

Stream bank stability, stream slope, sediment transport

Point source pollution

Wastewater discharge, urban stormwater pipes

36 SEPTEMBER 2010 water

Native to non-native ratio

Channel geometry

feature articles


ll~ KDCH

MEMBRANE SYSTEMS •

Our engineers are a breed apart. Experts in their field . Highly ex perienced. Passionate about their work. Go to www.kochmembrane.com/bundamba.

They immerse themselves in your situation, your organization and your needs . And they know how to work efficiently on a tight schedule without sacrificing quality. We bring together more than 40 years of:

Download our free white paper on the Bundamba Water Treatment Plant. Discover how the biggest membranes in the industry helped Bundamba become one of the most energy efficient treatment ~ - - , plants in Australia.

Innovative membrane fi ltration technology Standardized and custom-engineered systems Superior quality products • Field service supporting nearly 20,000 locations worldwide All for one purpose .. .your next call.

Experience the Power of E3 ENGINEERING • EXCELLENCE • EVERYDAY

2008 - GWI WATER

L PROJECT OF YEAR

Also learn how: • Aggressive construction schedule was met (not only met but exceeded by a few weeks) • RO system demonstrated lower fouling rates • Using large diameter elements reduced footprint by 40%.

www.kochmembrane.com Corporate Headquarters: Koch Membrane Systems, Inc., 850 Main Street, Wilm ington, MA 0 1887 USA T: 1.888 .677.5624, F: 1.978 .657.5208 Koch M e m b rane Systems, Inc . is a Koch C he mical Techno logy Gro up, UC compa ny.


feature article Table 3. Survey responses - land parameters. Parameter Group

Parameter Importance A - Priority

B - Secondary

C- Low/ None

Biodiversity

Land use, soils and erosion risk, salinity, urban sprawl, development applications, planning schemes, declared source water boundaries Management practice, livestock density, fertiliser application, nutrient generation rate Ecosystem health, vegetation cover

Native vegetation

Pest plant and animals, rabbit activity, weed extent and severity, endangered species

Pollution sources (location and management)

Contaminated sites, mines, landfills, roads, septic tanks, urban runoff

Land use condition and planning Agriculture

Table 4. Survey responses - community, social and other parameters. Parameter Importance

Parameter Group

Community and Social Community/ social

Catchment projects

A - Priority

8 - Secondary

C- Low/ None

Human population size and density, catchment education, legislative tools strategies and polices Current and completed projects, other restoration activities

Financial input to catchment, socio economic data, Land Care and Water Watch participation

Value of agricultural production, indigenous cultural information, early European settler information

Climate change

Greenhouse gas emissions, carbon storage

Other

(e LOWARA

The Next Step Hydrovar is the world's first pump mounted microprocessor based pump controller. It does much more than just change pump speed, it truly manages your pump to match a wide range of system conditions. Energy savings of up to 70% can be achieved.

Contact us now about your specific application. Melbourne

03 9793 9999 Sydney

02 9671 3666 Brisbane

07 3200 6488

The next step in t his process is potentially the development of a standard framework for catchment c ondition reporting for drinking water, potentially using information f rom t he survey as a guide. Ideally, this framework would assist water authorities to address requ irements under the Australian Drinking Water Guidelines regard ing management of the risk in drinking water catchments. Although a framework needs to be flexible enough to include the diversity of parameters required by each authority, standardisation of reporting frameworks wou ld greatly facilitate the comparison of catchments and assist the tracking of progress at a national and internat ional scale. The author thanks the fol lowing organisations for partic ipating in the survey: ACTEW-AGL, Barwon Water, Central Highlands Water, East Gippsland Water, Gippsland Water, Hunter Water, Melbourne Water, SA Water, SEQ Water, South Gippsland Water, Water Corporation, Westernport Wat er and Victorian Department of Health. Funding for this project was made available from ACTEW Corporation 's Applied Researc h and Development Program.

Web: www.brownbros.com.au Email: info@brownbros.com.au

~n n Iii 1

!'..lf1i1

38 SEPTEMBER 2010 water

Bro"'."n Brothers Engineers Australia Pty Ltd

The Author James Gourley is a Senior Consultant with ALS Wat er Resources Group and was previously East Gippsland Water's Manager - Environment and Water. Email: james.gourley@alsglobal.com.

feature articles


A.BB Australi a P ty Li mited =or enquiries phone: 1300 782 527 Nww.abbaustralia.com.au

Power and productivity for a better worldâ&#x201E;˘

jl 1111 ,.,1,1,


feature article - opinion

Environmental Water Allocation: Some Unresolved Issues Dr John J Pigram, Adjunct Professor, University of New England. Before his retirement as Professor he had over 40 years experience in research, teaching and administration in water policy and water reform. A policy of allocating wat er for environmental purposes is now well established and widely adopted across the Aust ralian water sector. All state water management agencies and the federal government are active in promoting the sharing of water resources, primarily in the interests of sustaining the ecological values of river systems, wetlands and estuaries. Certainly, the Federal Minister for Water has been active in implementing such a policy which she described as "one of the largest adjustments (to resources management) Australia has ever seen". Another influential body, the Wentworth Group of Concerned Scientists, is also an enthusiastic advocate of restoring river flows closer to their natural state. The most recent proposal from the Group calls for an overall reduction of 30 per cent in diversions of surface water for agriculture in the Murray-Darlin g Basin, with the Murrumbidgee Valley alone to lose 65 per cent of its allocations. It is estimated that reducing extraction of water on this scale wou ld return rivers to approximately two-thirds of their natural flow, and contribute to a more environmentally healthy future for the Basin. Given the economic and social implications for rural and urban wat er users, the issue of environmental water allocations has emerged as a most controversial and demanding aspect of the water reform initiative. As with many confl ict situations, the problem lies not in what is proposed but in how it is put into operation. When the process of environmental water allocation and adjustment is scrutinised a number of shortcomings can be identified that compromise ready acceptance of the outcomes sought. Among unresolved issues are: â&#x20AC;˘ Lack of attention to the importance of accountability for the use of water diverted for environmental purposes â&#x20AC;˘ Inadequate understanding of the diverse nature of the riverine environment â&#x20AC;˘ Neglect of the need for structural adjustment and for integrating environmental water allocations with other resource uses and comm unity concerns

Accountability One of the most pressing issues that awaits resolution in the implementation of water reform in Australia is the relative lack of accountability for the use of the resources diverted to the environment from irrigation and other economically productive purposes. This is in sharp contrast to accountability standards imposed on consumptive uses of water and on other public investments and initiatives. In the context of environmental water allocations accountability includes a number of related phases: justification; specification; management; monitoring; and auditing.

40 SEPTEMBER 2010 water

In the first place, a fu ndamental requirement is a documented case justifying the need for, and the purpose of, the environmental water allocations sought. It is not sufficient to cite perceived deterioration in ecosystem integrity as justification to divert substantial volumes of water to address these supposed deficiencies. A detailed case needs to be made spelling out how environmental flows will restore the integrity of targeted ecosystems. Given current imprecision in knowledge of the water-based requirements of these systems, demands for environmental water allocations often seem to be in the nature of an "ambit" claim on the water resource. This only reinforces opposition and resistance to what is seen as a largely undocumented push to reclaim water presently in use for irrigation, industry and urban needs. Some attention is being directed towards identifying a number of specific sites in the Murray Valley for remediation. More common ly, however, claims for envi ronmental water are generalised as part of a broader program intended to improve the health of river systems and related waterways. Not only should the purpose for making environmental water allocations be justified in detail, but the way in which the water is to be used should be specified in terms of the location and extent of areas to be target ed, the timing of releases, the duration of flows, etc. Otherwise the environmental water could be wasted , misdirected and ineffective. Closely related to these requirements is the need for a detailed management regime for the water that has been justified and specified for environment al purposes. Management protocols need to be spelled out detailing specific attributes necessary to achieve the environmental objectives set down. Vague indicators for management of environmental flows wi ll be counter-productive and likely to negate the rationale under which the wat er has been acquired and made available. Furthermore, no allocation of water for environmental purposes can be expected to succeed without ongoing monitoring and auditing of the resu lts. Monitoring enables an assessment to be made of so-called "sustainable diversion limits" on extraction of water from river systems. It also indicates the need for possible adjustment and fine-tun ing of the management reg ime - in terms of insufficient water diverted; excess diversions beyond what is specified; or misdirection and waste of the resource designated for the environment. Finally, ongoing monitoring of the progress of environmental flows needs to be supplemented by periodic auditing as an essential component of the accountability process. No significant allocation of public funds should be made without provision for thorough assessment of the outcomes. Yet, vast amounts of water are being set aside for the environment in the absence of any systematic attempt to determine their effectiveness. This omission is compounded

feature articles


/"'

\

AUSTRALIAN PUBLISHING RESOURCE SERVICE

by incomplete appreciation of t he complexities of t he riveri ne environment targeted for remediat ion.

The Riverine Environment It is important to recognise that a riverine environment is multifaceted and comprises a range of sub-environments not all of them compatible, mutually supportive or reinforcing. These include, among others, the stream chan nel and aquat ic life, bank zones and wetlands, riparian vegetation and bird life, and human social and economic aspects.

~

' Australian Water Management Review

With in this mosaic a number of interrelated environments can be recognised, for example, an environment for aquat ic biota; for fish of different species; and for water birds; each with its own discrete water needs. The many individual environments that make up the whole may mean that reserving or releasing water for one could be at the expense of another. For instance, can water be allocated and delivered to support a water bird breedi ng event without sacrificing alternat ive, competing environmental claims? The typical diversity of the riverine environment makes difficult the task of providing effective and equitable water allocations to satisfy the needs of a healthy river system and its several components. It is open to question whether resource managers can be confident of meeting this challenge, especially when knowledge and understanding of environmental water requirements remain incomplete. Despite t he efforts of agencies like t he Healthy River Commission in New South Wales , there seems little consensus on what constitutes a "healthy river", or how far to go towards restorat ion and rehabilitation of a degraded stream envi ronment. Indeed, remediat ion strategies being implemented in t he interests of healthier rivers seem t o reflect the not ion that enhanced ecological outcomes and improvement in the biophysical parameters of the stream environment must receive priority at the expense of rural and urban water allocations, even if social welfare and regional economies are threat ened as a result. Yet, in a holist ic approach to river health, ecological values would be only one measure of a healthy riverine system. Economic prod uctivity, social wel lbeing and cultural aspects also need to be taken into account.

informative editorial

.

. ..

...

.

early due to the high level of interest

. ..

wish to subscribe to the review Rlease email

-

Equally vit al is the chal lenge of structural adjustment to the changed circumstances facing a regio n denied an adequate supp ly of irrigation water.

Structural Adjustment Structural adjustment is, or should be, an essential component of the water reform agenda, but is often a neglected aspect of t he process. Structural adjustment reflects the importance of adopting an integrat ed approach to environmental water allocations, whether this is by vol untary transfer of water entitlements or by purchase with public f unds. Rat her than a "buy-and-dry" outcome for dewatered irrigated lands, the focus should be on t he structure and functioning of the overall river system, incorporating knowledge and understanding of ecological processes, economic data and socio-cult ural considerations, with the added strength of interact ive stakeholder involvement in the process.

1d r19 your £•rnail c.lddmss you consoi I lo receive uny I rna1I regarding tt11s n'f!TlZIPO, oml ottior cma ·s v.rh1(;1 • nfo m ', ou of APRS's other '"~!J~1>nl3S


feature article - opinion In situations where off-stream water allocations for irrigation and other consumptive purposes are to be reduced to satisfy biophysical concerns for the riveri ne environment, the need for structural adjustment has to be addressed, trade-offs calculated and provision made to offset predicted detriments to economic wellbeing and comm unity welfare. This approach rests on an agreed set of criteria for the evaluation of outcomes in terms of river health, sustainability and biodiversity of the overall stream environment and ongoing support for the economic and socio-cu ltural values of the affected comm unities. It must be recognised that the fundamental structure of an irrigated region is altered when water - the driving force behind a valley's economy and community strength - is taken out of production. Making available some form of compensation to those affected offers only short-term relief. What is requi red is far-reachi ng adjustment to the pre-existing foundations of the regional economy, if it is to remain viable. Reaction to these changed circumstances rest s largely with water management agencies and government policy makers. Part of a package of public policy measures to facilitate change might include fu nding support for irrigators to adopt different land use practices at the farm level in keeping with a red uced water supply, along with retirement of irrigated land, retraining and relocation of affected communities. Longer-term

adjustment needs t o be directed towards promoting resil ience with in the irrigation sector and strengthening institutional mechanisms to support the movement of resources into and out of irrigated agriculture. Inevitably, much of the burden of effective structural adjustment demands positive action by the irrigators themselves to the new water-scarce environment. Steps that might be taken at the farm level include: efforts to improve water use efficiency by upgrading of farm layout and design of water supply and drainage systems; improved land preparation including piping and lining of delivery channels to reduce seepage losses; recycling and reuse of diminished water supplies; application of irrigation scheduling techniques to match plant demand and soil characteristics; and switch to dry land agriculture, or at least to selection of crop varieties with lower water requirements. Neglect of comprehensive structural adjustment programs makes meaningless targets such as "improving river health" and puts at risk longer-term outcomes of water reform. Without supportive structural adjustment measures to mitigate economic and social disruption of water-dependent commun ities, accompanied by provision for ensuring accountability for the policies implemented, significant impediments are likely to stand in the way of integrated and sustainable use of Australia's land and water resou rces.

Works better under pressure.

That 's why he's the perfect Mono employee. He thrives on pressure, and we have the highest pressure PSS pumps on the market. He knows great pressure can mean great freedom. Because the more of it you have, the further it'll take you.


The new Thermo Scientific Orion DUAL STAR~ pH/ISE meter has been added to our growing family of water quality products. Take two pH/ISE/ORP measurements at once using the dual inputs of the new Orion DUAL STAR meter. Great for potable water labs measure pH and fluoride from the same sample at the same time. Meter prompts and direct ion concentration readout (with custom options) make this meter perfect for any user, regardless of experience. To receive more information on the Orion DUAL STAR meter, or any other Thermo Scientific product call 1300 735 295 or visit www.thermofisher.com.au

Moving science forward

Thermo Scientific Orion DUAL STAR Meter Ideal for water and wastewater laboratories, from basic to advanced applications.

Thermo SCIENTIFIC

Part of Thermo Fisher Scientific


~

wastewater treatment

refereed paper

PATHOGEN REMOVAL BY A MEMBRANE BIOREACTOR L Pettigrew, M Angles, N Nelson Abstract The performance of membrane bioreactor (MBR) tech nology in relation to the microbial Log Reduction Val ues (LRVs) outlined in the Australian Guidelines for Water Recycling (AGWR) is not we ll characterised nor widely published. The LRVs for a fully operational 2 MUd MBR for internal on-site use at a sewage treatment plant (STP) were determined based on the number of indigenous microorganisms found in primary treated sewage. The MBR achieved log removals in the range 4. 75 - 6.23 for F-specific RNA bacteriophage, 5.41 - 6. 70 for E. coli and 3.66 - 5.19 for somatic coliphage. The MBR reduced Cryptosporidium, Giarda and human enteric viruses present in the influent to below detectable levels. The LRV values for the MBR were found to be similar to the indicat ive LRV range given for membrane filtration in the AGWR, despite being limited by t he number of microorganisms present in the influent.

Context The increasing implementation of recycled water schemes has prompted the development of a national guidelines document (AGWR). Any new recycled water scheme is required to prove that the quality of treated water it prod uces can be considered safe for its nominated use. The AGWR does this by establishi ng a set of LRVs for pathogens for various end uses and indicative LRVs for various unit treatment processes (NRMMC 2006). Disinfection processes such as UV and

water Future Features DECEMBE R - Trenchless technology, pressure sewerage, water policy FE BRUARY - Sewer processes, smart systems, metering APRIL - Membranes and desali nation , reuse

44 SEPTEMBER 2010 water

chlorination are generally supported by extensive validation and tech nology verification data that has been widely published. There is also now increasing evidence of the effectiveness of secondary treatment to meet LRV targets of the AGWR (Flapper et al. 2010). By and large, however, there is an overall lack of data for specific treat ment processes to support better defined LVRs in the AGWR. This is true of MBR t reatment processes. While a range of indicative LRVs are given in the AGWR for secondary treatment and membrane filtration, no indicat ive LRV has been provided for a combined treatment process such as an MBR. MBRs have gained in popularity in recent years d ue to decreases in capital and running costs and increasing demand for higher quality treated water for reuse and/or discharge. Importantly, the main advantage of MBR systems is their ability to provide consistent high quality wat er within a smal l footprint. These factors have made MBRs an attractive treatment option for smal ler decentralised systems. The Water Industry Competition Act 2006 has been developed in NSW to increase private participation in the water indust ry. This has resu lted in an increasing number of decentralised recycled water projects. Further research and learnings from on-ground schemes will help to inform future legislative and guideline changes around Australia. Sydney Water established an indust ry working group in June 2007 to monitor a cross-section of small-scale decentralised recycled water systems in Sydney. The main objective of the working group is to better understand the implications of decentralised recycled water systems by sharing knowledge and learnings. Sydney Water also wished to improve understandi ng of the interface between decentralised recycled water systems and its own operations. This is

Excellent results throughout five year's operation.

in regard to issues such as recycled water quality, potable water savings and residuals management. The worki ng group was also t asked with understanding the key issues being faced by developers w ishing to implement small-scale recycled water schemes in NSW under the Water Industry Competition Act 2006. All schemes being monit ored use MBRs, which in terms of current regulatory requirements provide an uncertain level of effectiveness in the removal of microorganisms due to a lack of information and data from existing schemes. There is concern regarding the potentially high costs of validating smaller schemes so as to meet t he cu rrent regulatory requirement s. In order to address t he lack of information, Sydney Wat er undertook an initial study of an MBR recycled water plant (RWP) to determine its effectiveness in removing microorganisms. The MBR plant is located at Sydney Water's North Head sewage treatment plant. The RWP has been in operation since 2005 w ith a relat ively constant production rate.

Recycled Water Plant Overview The recycled water plant used in the study was commissioned in 2005 and comprises a membrane bioreactor configured as a Modified LudzackEttinger (ML E) biological process with t he clarifiers replaced by membrane separation units (Figure 1). The recycled water plant t reats Screened Settled Sewage (SSS) to produce fit for purpose recycled water for on-site use in t he STP (cooling water for pumps, screen spray water, surface wash-down, chemical dilution and firefighting). The MBR plant produces up to 2 MUd of product water. The plant is fully automatic in operation, including start-up, shutdown and monitoring procedures (Briggs et al. 2007). The MBR is fed continuously from the STP's primary sedimentation tanks. There is dosing of ferrous chloride into the sewer approximate ly 35 km up stream of the plant to control odour.

technical features


Parsons Brinckerhoff (PB) is a global leader when it comes to designing and delivering strategic infrastructure for water. Right now we are working on major water projects around Australia - and more are in the pipeline. That means we're looking for innovative professionals to take up roles that matter within our organisation including Design Managers , Project Managers and Design Engineers . GLOBAL. INNOVATIVE. LEADING. FLEXIBLE. MAJOR PROJECTS. CAREER BUILDING. Are you ALL OF THE ABOVE? Visit www.pb.com.au

PARSONS 7~ BRINCKERHOFF 25

rEARS


~

wastewater treatment The MBR system comprises separate aerated, anoxic and solids separation zones (membrane zone) (Figure 1). Permeate from the membrane zone is dosed with sodium hypochlorite to provide a chlorine Contact Time (CT) of at least 30 mg.min/ L. The membranes are hollow fibre with a 0.04 µm nominal pore size. The recycled water produced by the plant is requ ired to meet the following criteria based on the ANZECC guidelines (2000) for urban non-potable reuse (residential) reclaimed water use: • Ammonia < 1 mg/L • Thermotolerant coliforms <10 cfu/ 100 ml • Turbidity < 2 NTU (24 hr mean) • Insoluble iron <0.Smg/ L • Alkalinity > 40 mg/ L

Methodology - Log Reduction Verification Given the practical difficulties and costs in challenge testi ng fu lly operat ional MBR processes, the indigenous surrogate microorganisms in the SSS were used to determine the LRV for various pathogens. E. coli, F-specific RNA bacteriophage, somatic coliphage and Bacteroides

Aerobic Zone

Anoxic Zone

i

I

~

ct

De-aeration Mixed Liquor Return Line

(aerated)

l

- 4

-

Contact Tank

Figure 1. Layout of MBR system showing sampling points (red arrows): 1 - influent; 2 activated sludge; 3 - permeate; 4 - effluent. fragilis phage (Bacteroides phage) were used as indicator organisms representing bacterial and vi ral pathogens. The study focused on viral surrogates as a conservative microorganism as they represent the greatest challenge to the membranes. It was assumed that if E. coli was removed then Cryptosporidium, being larger, would also be removed. Nevertheless, to verify the removal of pathogenic organisms, t he study also included two sampling events using background levels of Cryptosporidium and Giardia and human enteric viruses. Six sampling events were undertaken. On each sampling event an individual

Influent

Permeate*

Log removal

1

6.20x104

<1

2

8.40x105

<1

3

6.80x105

3

4

2.80x105

<1

5

2.70x105

6

3.90x105

> 5.09 > 6.23 5.36 > 5.75 5.43 4.75

7

E. coli (0rgs/100ml ) Influent

Permeate

Log removal

1.00x107

22

5.66

2

7.30x106

13

5.75

3

7.70x106

23

5.52

4

1.00x107

13

5.89

5

1.30x107

50

5.41

6

2.00x107

4

6.70

somatic coliphage (pfu/100ml) Influent

Permeate

4.60x10 5

3

5.19

2

7.1 0x10 5

17

4.62

Log removal

3

5.90x10 5

6

4.99

4

8.50x10 5

21

4.61

5

7.20x105

13

4.74

6

9.50x105

210

3.66

• Values of <1 were replaced with 0.5 for Jog calculations

sample was taken from each of the following four locat ions (Figure 1): 1. The MBR feed line t o the anoxic zone (influent). 2. The aerated membrane zone (activated sludge). 3. Prior to t he chlorine contact tank (permeate). 4. After the chlorine contact tan k (effluent). The last sampl ing event was conducted one month after the first five events. A membrane clean-i n-place (GIP) occurred between samples 5 and 6. Microbiological analyses were performed at Sydney Water's laboratories using methods accred ited by the National Association of Testing Authorities, Australia (NATA).

F-specific RNA bacteriophage (pfu/100ml)

46 SEPTEMBER 2010 water

Storage

Chlorine

Table 1. Log removal of surrogate organisms through MBR process (excluding chlorination). Sample No.

Membra ne Zone

I

I

Feed

r

ref ereed paper

Results and Discussion Log removal of microorganisms by MBR The MB R achieved LRVs in the range of 4.75 - 6.23 for F-specific RNA bacteriophage, 5.41 - 6.70 for E.coli and 3.66 - 5.19 for somatic coliphage (Table

1). Samples 1-5 were taken weekly. Sample 6 was taken one month after sample 5 and one week after a GIP. Al l samples were taken in February and March of 2010.

Bacteroides phage was tested for on all sampling events and at least 3-log removal was shown (Table 2). Cryptosporidium and Giardia concentrations were determined on two occasions to assess t he plant's ability to remove protozoa. In both cases, at least 3-log removal of Cryptosporidium and Giarda was shown (Table 3). Two sampling events were undertaken to test for the presence of the human

technical features


A cleane~ greener approach to water sterilisation fo r water treatment plants ! Australian Innovative Systems Pty Ltd (AIS) has specialised in products that disinfect water via electrolysis since 1974 and now has developed the world's first eco-efficient system, Ecoline™, which sterilises drinking, waste and swimming pool water. EcolineTM is changing the way water is being disinfected and treated. Utilising the natural salts and minerals already existing in the water, Ecoline™, through a process of electrolysis, instantly sterilises water. Ecoline™ eliminates the risks involved with chemical handling including transporting, storing and dosing to the water supply. Ecoline™ lowers operating costs and achieves a complete automatic process that requires minimal operator attendance.

. ..,

..

I

Applications: Drinking water, Recycled water, Grey

f~

water, Sewerage and wastewater, Irrigation water, Food processing plants,Cooling towers, Reverse osmosis / desalination, Agricultural lagoons, Swimming pools e,- Water features.

co eco line™ WATER TREATMENT OF THE FUTURE

P R O

U

D

INTERNATIONAL

BUSINESS AWARDS)

I

, • • eco

••

A W

.

fier ...,.,,

A

R D

WINNER

GAiA A\\ :l DS 2009 GCLD

www.aiswater.com.au • info@aiswater.com.au • Telephone: +61 7 3396 5222 • Facsimi le: +61 7 3393 3441


GJ

wastewater treatment enteric viruses, adenovirus, enterovirus and reovirus, through the MBR process. There were no detections of vi ruses after membrane filtration in either sample At least 2-log event (Table 4, Table removal of pathogenic viruses was shown. However, the log removal of pathogenic viruses was limited by the relatively low concentrations in the influent.

s,.

Previous studies of MBR systems have been either bench or pilot scale and utilised municipal wastewater as the influent. Results from these previous studies were comparable to this study albeit the pore sizes used in these studies were larger than those used by Sydney Water's MBR plant (0.04 µm nominal pore size). Lv et al. (2006) showed a 5.8-log removal of phage by 0.1 µm nominal pore size membranes. Ueda and Horan (2000) showed a maximum 5.9-log removal of indigenous bacteriophage across a ben ch-scale MBR process that included 0.4 µm nomin al pore size membranes. Ottoson et al. (2006) used 0.4 µm nominal pore size membranes and achieved a 5-log removal of E. coli and 3.8-log removal for F-specific phages. The high log removal of viruses t hat are smaller than the nominal pore size in the study has been attributed to the presence of a fou ling layer (Ottoson et al., 2006).

Organism fate through MBR process A sample was taken from the membrane zone to compare the concentration of microorganisms in the influent to that in the act ivated sludge (Figure 1). The mixing and concentrating of influent in the biological stage of the reactor, the quality of the influent over time and the disposing of waste wil l all affect the microorganism concentration in the activated sludge.

refereed paper

Table 2. Log removal of Bacteroides phage through MBR process (excluding chlorination). Bacteroides phage (pfu/100ml) Permeate*

Sample No. Influent

1.00x10 3

5 6

>3.30

<1 <1 <1 <1 <1 <1

3.40x103 9.80x1 03 1.40x10 3 1.00x10 3 3.00x1 04

2 3 4

Log removal

>3.83 >4.29 >3.45 >3.30 >4.78

• Values of <1 were replaced with 0.5 for log calculations

Table 3. Log removal of Cryptosporidium and Giarda through MBR process. Cryptosporidium (Adjusted for 50L and 100% recovery)

Sample No. Influent

Permeate*

Log removal

2

1.35x103

<1

> 3.43

3

6.48x103

<1

> 4. 11

Giardia (Adjusted for 50L and 100% recovery)

2 3

Influent

Permeate*

Log removal

1.2ox105 7.41x103

<1 <1

> 5.38 > 4.17

• Values of < 1 were replaced with 0.5 for log calculations

Table 4. Log removal of pathogenic virus through MBR process (excluding chlorination), SOL samples taken during sample 4. Influent

Permeate

1.00x103 1.00x103

<4

> 2.70

Enterovirus

> 2.70

Reovirus

5.00x102

<4 <4

Adenovirus

Log removal

> 2.40

Table 5. Log removal of pathogenic virus through MBR process (excluding chlorination), SOL samples taken during sample 6. Influent

Permeate

Log removal

Adenovirus

2.1 3x103

Enterovirus

2.50x102

Reovirus

1. 13x103

<4 <4 <4

> 3.03 > 2.10 > 2.75

1•

F-specific RNA Bacteriophage D E coli D Sorratic coliphage

The concentration of F-specific RNA bacteriophage was found to vary in the membrane zone in relation to the influent (Table 6). There was a general decrease in the number of E. coli in the membrane zone prior to filtration, while somatic coliphage were observed in consiste ntly higher concentrations (Table 6). Concentrations of Cryptosporidium and Giardia were observed to increase in the membrane zone before being completely removed by the membrane process (Table 7).

48 SEPTEMBER 2010 water

2

4

3

5

6

Sample No.

Figure 2. Log removal of selected microorganisms through the MBR process.

technical features


...

Water Quality Specialists providing analysers and sensors for the followi measurments:

pH Conductivity

Dissolved Oxygen ORP Chlorine and more

To contact your local Rosemount Ana lyt ica l sales represent atives, please ca ll us on

1300 -55-3051

ROSEMOUNT. Analytical

EMERSONN Process Management


Q

wastewater treatment Discussion of log removal values The number of microorganisms detected in the influent varied over time and as such the absolute LRV for the process varied accordingly (Figure 2). The number of microorganisms in the permeate remained consistently low in all of the samples and were not detected following ch lorination. Although the AGWR does not give LRVs for advanced treatment processes such as MBR, the log removals achieved in this study compare with the indicative LRVs given for membrane filtration (Table 8). The LRVs were great er than the AGWR indicative values for secondary treatment. Due to the consistent quality of the recycled water, a higher concentration of microorganisms in the influent would be expected to give a higher LRV. It is suggested that the maximum removal capacity of the MBR has not been reached in this study.

Conclusions This study represents an initial investigation into the pathogen removal of an MBR. The MBR plant used in this study was shown to be effective in removi ng selected pathogens from t he feed water after five years of operation. The LRVs achieved by this M BR are comparable to the indicative LRVs given by the AGWR for membrane fi ltration and are greater than those given for secondary treatment, which supports the results of earlier studies. The AGWR does not currently give indicative LRVs for advanced treat ment processes such as an MBR. As t his was an initial study, no correlation between MBR operational paramet ers and the removal of indicat ors or pathogens was undertaken. It is suggested that a larger more comprehensive study be undertaken to investigat e the impact of varying operational parameters, including clean in place and back washing, on microorganism removal by MBRs. Cryptosporidium and Giardia and human enteric viruses were reduced to below detectable concentrations by the MBR process. The surrogat e pathogens required chlorine disinfection to achieve complete removal. The measured LRVs correlated with the organism concentration in the influent as the quality of product water from the MBR remained constant throughout the samplin g regime. The results also show that an increase of organisms in the membran e zone did not produce a corresponding increase in the product

50 SEPTEMBER 2010 water

r e f e r e ed p a p e r

Table 6. Surrogate organism concentrations through the biological process. F-specific RNA Bacteriophage (pfu/100ml)

Sample No. 1 2 3 4 5 6

Influent 6.20x10 4 8.40x10 5 6.80x10 5 2.80x10 5 2.70x10 5

3.90x10 5

Activated sludge

Log difference

2.10x105 6.30x105 1.80x105 4.90x105 2.90x105 3.50x105

- 0.53 0.12 0.58 - 0.24 - 0.03 0.05

E. coli (Orgs/100mL)

2 3 4 5 6

Influent

Activated sludge

1.00x10 7 7.30x10 6 7.70x10 6 1.00x107 1.30x10 7 2.00x1 07

5.50x106 7.70x106 1.90x106

Log difference

0.26 - 0.02 0.61 0.54

2.90x106 3.10x106 3.70x106

0.62 0.73

Somatic Coliphage (pfu/100mL)

2 3 4 5 6

Influent

Activated sludge

Log difference

4.60x105 7.1 Ox10 5

4.30x106 2.80x106

- 0.97 - 0.60

5.90x10 5 8.50x10 5 7.20x10 5 9.50x10 5

2.90x106 4.90x106

- 0.69 - 0.76 - 0.67 - 0.50

3.40x106 3.00x106

Table 7 . Cryptosporidium and Giardia count through membrane process. Cryptosporidium (Adjusted for SOL and 100% recovery)

No.

2 3

Influent

Activated sludge

Log difference

1.35x103 6.48x103

5.15x104

- 1.58 - 0.59

2.50x104 Giardia (Adjusted for SOL and 100% recovery)

2 3

Influent 1.20x105 7.41 x103

Activated sludge

Log difference

1.51x106 3.26x104

- 1.10 - 0.64

Table 8. Comparison of AGWR indicative and studied log removal for various microorganisms. Average size (11m) E. coli Viruses Phage Giardia Cryptosporidium

0.6 - 2.5 0.02 - 0.08 0.02 - 0.27 7-10x12 -1 8

4-6

AGWR (NRMMC 2006) Indicative log Indicative log removal (Secondary) removal (Membrane) 1.0 - 3.0 0.5 - 2.0 0.5 - 2.5 0.5 - 1.5 0.5 - 1.0

3.5 - >6.0 2.5 - >6.0 3.0 - >6.0 >6.0 >6.0

Log removal achieved in this study* (MBR) 5.41 - 6.70 >3.03 3.66 - >6.23 >5.38 >4.1 1

â&#x20AC;˘ The log removals achieved in our study were limited by the concentration of microorganisms present in the influent.

water. This suggests that the MBR could potentially remove a higher concentration of microorganisms and achieve greater LRVs than those measured in this study. The MBR was shown to cope well with

variabi lity in the influent and provide a consistent quality product water. No notable decrease of the studied microorganisms was observed prior to membrane filtration. It is suggested that

technical features


Q

wastewater treatment

ref ereed paper

the membranes of an MBA are t he primary barriers to the microorg anisms analysed in this study. Fouling caused by the activated sludge in the membrane zone cou ld be enhancing the membrane barrier as indicated by oth'e r studies that showed comparable vi rus removal using membranes with larger nominal pore size than those used in the current study. This study shows that with a proper operations and maintenanc e system in place it is possible to produce high quality recyc led water from an MBA throughout five years of operation .

Acknowledgments The work presented here would not have been possible w ithout the support and the assistance of Cheryl Marvell , Susan Ireland , Adrian Montgomery and Wanxin Wang from North Head sewage treatment plant.

The Authors

Liam Pettigrew was a graduate in the Syd ney Water graduate program. Liam has left Sydney Water to pursue a career in Europe.

Mark Angles is a Project Manager in Sydney Water's Science & Technology group. He has 14 years of experience ad vising on water quality and public health issues. Email: mark.angles@sydneywater.com.au

Industry Comment on MBR Validation By Kurt Dahl, Managing Director, Permeate Partners Membrane Bioreactor's (MBA's) are fast becoming the default technology for high quality recycled water production, in particular for small systems of less than 2M LD/ day. In parallel with this trend is the move towards assignment of pat hogen log removals for individual unit operations vs end of treatment testing. At present there is a lack of agreement between technology providers, consu ltants and regulators on what MBA's can achieve in t erms of pathogen removal. As an example some technology providers and consultants believe removal of viruses across the MBA is >4 log, whereas, some regulators have shown a reluctance to grant > 1 log unless supported by comprehensive, detailed, and therefore expensive, on-site testing. This lack of consensus is problematic for current and future MBA owners in establishing the credentials of t heir current/proposed flowsheet in relation to the Australian Guidelines for Water Recycling. In extreme cases a number of proponents are considering the use of a dual membrane system whereby a 2nd set of membranes is used to process MBA permeate. This approach enables proponents to use established pathogen log removal values for tertiary membrane filtration and avoid the need to assign any log removal credit to the MBA. Understandably this level of

Allgeier, S. (2005). Membrane Filtration Guidance Manual. United States Environment al Protection Agency. Sarkis, S. (2009). Guidelines for validation of treatment processes. VicWater Annual Conference, Department of Health.

Nicola Nelson is a Program Manager in Sydney Water's Scienc e and Technology Group. She is responsible for A&D to better understand the role of decentralised recycled water systems in urban water management.

References US EPA (2005). Protocol for Equipment Verification Testing for Physical Removal of Microbiological and Particulate Contaminants. United States Environmental Prot ection Agency, NSF International.

Power, K. (2010). Recycle d Water Use in Australia: Regulations, Guidelines and Validation Requirements for a National Approach. National Water Commission. Briggs, J., Helmy, M. , Landers, G., and Gabriel, I. (2007). "Operational Review of the North Head Membrane Biore actor in Sydney, Australia." W EFTEC 07 . Flapper, T. G. , Campbell, B., Deere, D., Blackbeard , J., and Halliwell, D. (2010). "Quantifying Pathogen Log Reduction in Australia Activated Sludge Plants." Journal of the Australian Water Association, 37(1), 56 . 61.

disinfection redundancy has a significant impact on project viability. Of equal importance to establish ing log removal performance of new membranes, is ensuring t hey continue to perform in accordance with expectations over the long term. In drinking water and tertiary filtrat ion, membrane owners have used one or a combination of permeate turbidity, pressure decay and particle counters to demonstrate membrane integrity. Historically, MBA's have on ly used turbidity to confirm the membrane barrier is intact. This approach has merit in MBA 's due to differential in solids content on either side of the membrane - typically 10,000mg/L vs 1mg/ L or 5 log removal of solids. However, the link between solids removal and pathogen removal is not well understood and/ or characterised in MBA applications. The testing undertaken at North Head by Sydney Water is the first step in developing a greater understanding of MBA pathogen removal. To ensure the benefits of MBA technology are fu lly realised it is critical that all stakeholders work quickly and collaboratively t o identify and agree on an appropriate and practical methodology for assigning, approving and monitoring the log removal performance of MBA's. Until we understand the fat e of pathogens through the MBA process, the mechanism of pathogen removal and options for monitoring short and long performance, MBA technology will continue to be undervalued .

Lv, W., Zheng, X., Yang, M., Zhang, Y., Liu, Y., and Liu, J. (2006). "Virus removal performance and mechanism of a submerged membrane bioreactor." Process Biochemistry, 41(2), 299-304. NRMMC. (2006). "Nat ional Guidelines for Water Recycling: Managing Health and Environmental Risks." N. R. M . M. Council, E. P. a. H. Council, and A. H. M . Conference, eds. Ottoson, J., Hansen, A., Bji:irlenius, B. , Norder, H., and Stenstrom, T. A. (2006). "Removal of viruses, parasitic protozoa and microbial indicators in convent ional and membrane processes in a wastewater pilot plant ." Water Research, 40(7), 1449¡1457. Ueda, T., and Horan, N. J. (2000). " Fate of indigenous bacteriophage in a membrane bioreactor." Water Research, 34(7), 2151¡ 2159.

water SEPTEMBER 2010 51


Q

wastewater treatment

refereed paper

VALIDATION OF DUAL MEMBRANE TREATMENT FOR INDIRECT POTABLE REUSE K Linge, P Blair, F Busetti, C Rodriguez, M Handyside, J Blythe, M Bromley, 0 Lord, S Higginson, A Heitz, C Joll, C Newby, S Toze Abstract The Western Australia's Premier's Collaborative Research Program (PCRP) project 'Characterising Treated Wastewater for Drinking Purposes Fo llowing Reverse Osmosis Treatment' commenced in October 2005, to determine t he potential risks of replenishing drinking water aquifers with MF/ RO treated secondary wastewater from Perth's wastewater treatment plants. A brief report on the project won the Michael Flynn Award for the best poster paper at Ozwater'10. The resu lts included t hose published in Water, February 2010, by Rodriguez et al, entitled Efficiency of RO for Removal of Chemical Contaminants . Consequently, this version has been drafted to cover the ot her aspects of the study, princ ipally the identification of suitable indicators which could be used to validate treatment performance.

Introduction In recent years Perth has experienced a significant reduction in wat er avail able from dams and groundwater. Population growth, decreases in t raditional drinking water sources and climate variabi lity mean t hat Perth needs to look increasingly at using water more efficiently and developing new water sources. One of several government strategies is through recycling of treated wastewater. However, a lack of knowledge of health and envi ronmental risks associated with chemicals in wastewater has been a barrier preventing establishment of large reuse schemes. In 2005 the Western Australian government awarded a grant to the Department of Health, Department of Environment, Water Corporation of Western Australia, Curtin University, ChemCentre, CSIRO and the National Measurement Institute to complete a

52 SEPTEMBER 2010 water

•~ · ---4

sc~:~Ns

NaOCI added below breakpoint NH3 added or present in wastewater stream

CHLORAMINATION

-~-

~----~ I MICROFI LTRATION

REVERSE

I

OSMOSIS

Figure 1. A schematic showing MF/RO treatment process and the sampling locations for wastewater, post-MF and post-RO samples. A pre-chloramination step used to protect the RO membrane is also highlighted and was found to increase concentration of some chemicals, such as disinfection by-products, during MF/RO treatment. collaborative project on recycled water quality in the context of potential reinjection to groundwater. The specific objectives of the project were: • To analyse the final treated wastewaters from the Water Corporation's three large metropolitan wastewater treat ment plants (WTTPs) to characterise their microbial and c hemical constituents and understand any seasonal and catchment differences in trace contaminants of concern in relation to human health and health of the environment; • To assess the performance of microfiltrat ion and reverse osmosis (MF/ RO) membrane treatment at the Kwinana Water Reclamation Plant (KWRP) and t he specially constructed Beenyup Pilot Plant (BPP), to consistently produce wat er meeting the various health and environmental guidelines for augmentation of drinking water supplies by re-injection into groundwater; • To use the research output to develop and refine health and environmental

Evidenced-based approach to recycled water safety for groundwater replenishment.

guidelines for aquifer recharge of recycled water for indirect potable reuse on the Swan Coastal Plain.

Chemical and Data Analysis Almost 400 chem icals, in 15 different chemical classes (see Table 1), were tested in the project. Eight laboratories were involved in the analysis and more than 20,000 records prod uced, not including field and trip blanks. Chemicals were selected for analysis based on their current use in Western Australia, their toxicological concern and evidence of detection in wastewater reported in the literature. Measured contaminant concentrations were compared with established drinking wat er standards and requirements or other toxicological guidelines to determine human health risks (Rodriguez et al. , 2007). As guidelines and standards had not been developed for many chemicals, t he threshold of toxicological concern was used for the preliminary health risk assessment to determine key contaminants that need to be monitored (Rodriguez et al., 2007). The data collected was used to calculate the percentage detection and median concentrations in wastewater and MF/RO treated water (post-RO water) for each chemical. Analysis by wastewater treatment plant (WWTP) and by season was also conducted. Treat ment efficiency was calculated for chem icals detected in wastewater using wastewater and post-

technical features


[]

wastewater treatment

refereed paper

RO samples matched for plant, date, and type of sample (grab or composite). Treatment efficiency was calculated as a percentage of removal from secondary t reated wastewater, based on the concentration in the post-RO sample. For those chemicals not detected in post-RO water, t he efficiency was calculated assuming a concentration equal to half the limit of detection as a conservative estimate. In these cases removal efficiency calculat ion was strongly influenced by the concentration measured in secondary wastewater. Where concentrations in secondary wastewater were close to detection limits t hen t he calculat ed removal was an underestimate.

serving a population of about 800,000. The Woodman Poi nt catchment, the source water to KWRP, is a more industrialised catchment than the Beenyup and Subiaco catchments and industrial waste forms 6% of wastewater. However all WWTPs have low industrial loading by international standards.

Sampling Sites Samples were collected from Perth's three main WWTPs: Woodman Point, Subiaco and Beenyup. These plants treat 85% of the wastewater produced in the Perth met ropolitan area and receive water from varied sources. The Beenyup WWTP serves the north of the city, which is mainly residential. The plant has a current capacity of 120 megalitres per day (MUday) that serves a population of about 600,000 and a plan ned upgrade t o treat 200 MUday. The Subiaco WWTP services the Perth central area and has a capacity of 61 MUday, serving a popu lation of about 300,000. This plant

Figure 2. Composite samples were taken using an automated ISCO 4700 refrigerated sampler over 24h. receives the effluent of several major Perth hospitals, though it is estimated that only 0.34% of wast ewater to Subiaco WWTP is sourced from hospitals, of which on ly 36% is classed as medical waste. The Woodman Point WWTP serves the south metropolitan reg ion with a capacity of 160 MUday,

Recycled water quality after MF/ RO treatment was evaluat ed at two plants: the operational plant located at KWRP , and the Beenyup Pilot Plant (BPP), wh ich was installed during t he project to t reat water produced by Beenyup WWTP. KWRP treats up to 24 MUday of wastewater to produce about 17 MUday of product water, while BPP treats about 96 kUday of secondary treated wastewater to produce about 67 kUday of RO permeate. As part of the MF/ RO process, it is standard practice to chloram inate wastewater before MF to minimise RO membrane fouling, and th is occurs at both BPP and KWRP. While the MF/RO treatment process is slightly different at each plant, both consist of an initial coarse pre-screening, chloramination and pH adjustment, MF, and RO membrane t reatment, as depicted in Figure 1. The majority of samples f rom KWRP and BPP were either wastewater or post-RO water. However, on a number of occasions, a post-MF sample was also taken, which provided an indication of t he impact of

Table 1. Summary of the 15 chemicals classes tested in the project, including the number of analytes in each class, and analytical methods used. More than 20,000 records were produced during the project, not including field and trip blanks. Laboratory

Chemical Classes

Curtin University

voes

Number of Analytes

57 32

Halogenated DBPs Inorganic DBPs (Anions) N-nitrosamines PAHs Phenols Complexing Agents Hormones Pharmaceuticals

3 9 17 16 4 4 36 11

Miscellaneous National Dioxin, furans and Measurement Institute dioxin-like PCBs

29

Chromium VI ChemCentre

Analytica I Method

Purge and trap gas chromatography mass spectrometry (GC-MS) Purge and trap GC-MS, liquid-liquid extraction (LLE) and derivatisation GC-MS, LLE-GC-MS Ion chromatography Solid-phase extraction (SPE) GC-MS Stirbar sorptive extraction (SBSE) GC-MS Derivatisation and SBSE-GC-MS LLE and derivatisation GC-MS SPE and liquid chromatography tandem mass spectrometry (LC-MS/MS) SPE-LC-MS/MS SPME-GC-MS, SBSE-GC-MS, LLE and derivatisation GC-MS, derivatisation and SBSE-GC-MS High resolution GC and high resolution MS Inductively coupled plasma optical emission spectrometry (ICP-OES) and colorimetric methods

Pesticides

117

GC with electron capture detection or nitrogen phosphorus detection, or GC-MS

Metals and Metalloids

28

ICP-OES, inductively coupled plasma mass spectrometry, or chemical vapour generation atomic adsorption spectrometry

Radionuclides

2

Sample preparation only for gross a and gross

2

Gas flow proportional counting

32

Various analytical methods

Radiation Health WA and ARPANSA

Gross a and gross

SGS

General wastewater parameters

~

particle activity

~

particle activity

water

SEPTEMBER 2010 53


wastewater treatment chloramination on the chemicals tested during the project.

Sampling Events Sampling during the PCRP project was carried out during seven approximately quarterly sampling events from December 2006 to October 2008 (PCRP, 2009, Rodriguez et al., 2010). Six sampling events were undertaken for all chemical classes, with an additional seventh sampling event undertaken for N-nitrosamines only. For most chemical classes, composite samples were taken over 24 h using an automated and refrigerated ISCO 4700 sampler (Figure 2). However composite sampling was not appropriate for unstable or volati le analytes and therefore grab samples were collected for those chemicals for wh ich concentrations were time-dependent. Field and trip blanks were collected on each day of sampling. For many chemical classes, preservation agents were requi red to preserve the analyte prior to analysis (PCRP, 2009) and these were added to the bottle prior to sample collection (or in the case of composite samples, prior to sub-sample collection). For bottles containing preservation agent, special care was taken not to overfill the bottle and thereby lose preservative. Replicate sampling of all samples was impractical because of the total number of samples and analytes collected, as well as limitations on the total volume of sample collected by the composite autosamplers. Replicate samples were , however, t aken in Events 4, 5 and 6 of both secondary wastewater (12% of samples) and post-RO water (8% of samples), and at both BPP and KWRP. Duplicat e samples were taken for all sample points in Event 7.

Analytical QA/QC and Inter-laboratory Testing A Quality Assurance (QA) program was implemented as part of the project to ensure data was reliable and of good quality. The National Measurement Institute (NM/) provided the QNQC coordination to the project and a number of publications and guidelines were taken into consideration, including Australian Standards for test methods (Standards Australia, 1990) and laboratory operation (Standards Australia, 2005), and standard methods for the analysis of water and wastewater (Eaton et al., 2005). During the project Curtin and CCWA developed in-house QA programs for their analytical methods, which were all

54 SEPTEMBER 2010 water

developed specifically for the project. NM / is NATA accredited laboratory, wh ile SGS uses NATA-accredited methods and therefore QA programs were already in place for the analyses they undertook. In addition to concentration data, each laboratory calculated method uncertainty, limits of reporting, precision, and bias or accuracy. Curtin also ensured that developed methods were scrutinised through appropriate peer review processes including consu ltation with leading international experts and publication of methods in peer reviewed journals (Busetti et al., 2009, Busetti et al., 2008, Busetti and Heitz, in press). Inter-laboratory testing was used to aid method validation where possible. Interlaboratory tests were organised by Curtin during Event 2 (May-June 2007) for selected antibiotics and pharmaceuticals. Other participants were National Measurement Institute (Sydney NSW), and DVGW-Technologiezentrum Wasser (Karlsruhe, Germany). A NATA-accredited proficiency test for 3 N-nitrosamines, a group identified to be of particular interest during the project, was undertaken through Proficiency Testing Australia in March 2008. This test was limited, however, because the sample supplied had a deionised wat er matrix and analyte concentrations about 3 orders of magnitude greater than those measured in the PCRP project. An additional N-nitrosamine inter-laboratory test was therefore organised by Curtin and undertaken during PCRP Sampling Event 6 (June 2008) for measurement of realistic concentrations in wastewater and RO water, with participation of 2 external laboratories, Queensland Health Scientific Services, and the Australian Water Quality Research Centre (SA). While there was insufficient data to perform a ful l statistical analysis, generally there was very good agreement between results from different laboratories.

Results An overview of the chemical results from the project have already been published in Water (Rodriguez et al., 2010) and therefore are not repeat ed in this article. Of the 396 compounds analysed, 195 were detected at least once in secondary wastewater, while 140 were detected at least once in post-RO water, albeit at very low concentration levels below health significance. Despite variations in wastewat er catchment, there were only minor variations in concentrations of chemicals between WWTPs, although seasonal differences were seen for some compound classes.

~

refereed paper

Health-based risk quotients were calculated for each analyte in secondary wastewater and post-RO water. N-nitrosodimethylamine (NOMA), a disinfection-by-product, was occasionally detected above the Australian Guidelines for Water Recycling (Phase 2): Augmentation of Drinking Water Supplies guideline value of 10 ng/L (AGWR, 2008). However, this guideline value is very stringent, being a tenth of the 100 ng/L limit in the WHO Guidelines for DrinkingWater Quality (WHO, 2008) and recently proposed for the Draft Australian Drinking Water Guidelines (ADWG, 2010). NOMA concentrations never exceeded 100 ng/L. Furthermore the average concentration of NOMA did not exceed 10 ng/L, and this is relevant as post-treatment maximum concentrations will be smoothed by retention in groundwater for months to years . For all other chemicals, the water quality achieved after the MF/RO treatment compl ied with ADWG and AGWR guidelines. Thus the MF/RO treatment process resulted in recycled water that meets the required health and environmental guidelines for augmentation of drinking water supplies. Eight compounds were found to have higher percentage detections (albeit lower median concentrations) in post-RO water compared to secondary wastewater, and this was attributed to contamination (e.g . toluene), formation during chloramination (e.g. halomethanes) and unintentional addition during the MF/RO process (e.g. acrylonitrile, chlorate). The ability to sample post-MF (see Figure 3) during the project was essential to underst anding the overall impact of MF/ RO on the chemicals t est ed, wh ich demonstrated that the chloramination procedure, membrane materials and anti -sealant chemical usage all need to be considered as potential sources of chemicals in postRO wat er. For chemicals that form or are added during treatment, calculations across the whole treatment trai n do not reflect RO removal efficiency and RO treatment performance requires monitoring immediately prior to RO rather than using secondary wastewater, particularly for disinfection by-prod ucts.

Microbiological and Toxicity Analysis The microbiological quality of the secondary wastewater was characterised at Beenyup WWTP and Subiaco WWTP. In secondary wastewater thermotolerant coliforms and enterococci were always detectable. Coliphages, often used as indicators of vi ral contamination, were detected in 95% of the Subiaco and

technical features


[\]

wastewater treatment

refereed p a per

Table 2. Treatment Performance Indicators were chosen based on the key properties for chemical rejection by MF/RO (size, hydrophobicity, polarity, acidic/basic character, and solubility in water) from chemicals detected in wastewater at sufficiently high concentrations with sufficient frequency (typically >80% detection). Secondary Wastewater % Detection

Median Removal Efficiency

Chemicals represented

NOMA (N-nitrosamines)

96%

Intermediate 79%

Small size, uncharged, highly polar organic molecules

Chloroform (DBP)

85%

Intermediate 82%

Small size, uncharged, non-polar, non-ionic organic molecules

Bromochloromethane (DBP)

94%

Intermediate 63%

Small size, uncharged organic, non-polar organic molecules

1,4-dichlorobenzene (VOCs)

95%

Intermediate 84%

Intermediate size, non-polar volatile organic molecules

EDTA (Complexing Agents)

100% 100%

Good 99.5%

Diclofenac (Acidic Pharmaceutical) Boron (Metals and metalloids)

100%

Intermediate 62%

Small size, charged inorganic molecules

Nitrate (Inorganic Anions)

100%

Intermediate 88%

Small size, negatively charged (anions), weak acid inorganic molecules

Carbamazepine (Non-polar pharmaceutical)

97%

Good 99.8%

100% of the Beenyup samples. Adenovirus were detected in 68% of the Subiaco and in all of the Beenyup wastewater samples. No microbial parameters were detected after MF/ RO treatment. Two challenge tests were undertaken at BPP using the coliphage MS2 as an indicator of enteric viruses to assess the capacity of the RO membranes to exclude such viruses. The results showed that the RO membranes alone were able to achieve at least a 4

Good 99.6%

Large size, polar charged, acidic organic molecules Large size, polar, slightly hydrophobic, acidic organic molecules

Moderately large size, non-polar uncharged organic molecules

log removal (i.e. 99.99% removal) of virus.

micronucleus assay, which measures DNA damage, the arrest of cellular growth and multiplication, and cell toxicity (Fenech, 2007).

Health effects of chemical mixtures were not specifically addressed in the screening health risk assessment conducted in this study. However, no cytoxicity and genotoxicity were observed when human cells were exposed for three hours to secondary treated wastewater or post-RO water samples using the cytokinesis-block

Indicators for Future Monitoring A key outcome of this research was the identification of chemical indicators of RO treatment performance and recycled water quality indicators relevant for Western Australia. Following Drewes et al. (2008), in this study an indicator was

AdvanTexe Provides Sustainable, Reliable Wastewater Treatment • Fit-for-purpose solutions for residential , small community and commercial applications • Third-party and field-tested verification of superior treatment • Low power costs and lifecycle costs • Optional 24/7 monitoring via remote telemetry • Easy to service; trained installers and service providers • Residential system approval in NSW, Queensland, Victoria, WA

NOT a suspended-growth ATU (Aerated Treatment Unit) NO discharge of untreated sewage NO powe r hungry blowers NO odours A.

AX20 for midmtial and 1ms1/I rommtrc-ial. Tix sy,tnn is

modular - 11dd11dditiom1I AX20s far hithtr flow,,

wastewater specialists

Supplied in Australia by lnnoflow Australia Pty Ltd. at 1800 466 635 Visit www.innoflowtechnologies.com for more information.

. • •

.

I--:.,

water SEPTEMBER 2010 55


~

wastewater treatment

refereed paper

Table 3. Additional Recycled Water Quality Indicators chosen for chemical classes where no chemical was detected in wastewater with sufficient concentration or frequency to be used as a Treatment Performance Indicator. Secondary Wastewater % Detection

Median Removal Efficiency

Chemicals represented

Trifluralin {Pesticides)

91%

Good 97%

2,4,6-trichlorophenol {Phenols}

64%

Intermediate 82%

Moderately large size, hydrophobic, moderately acidic organic molecules that are uncharged or charged depending on pH

Fluorene {PAHs)

64%

Intermediate 75%

Moderately large size, non-polar uncharged, hydrophobic, purely aromatic organic molecules

Octadioxin {Dioxins, furans & dioxin-like PCBs)

67%

Intermediate 72%

Large size, uncharged hydrophobic organic molecules

Estrone {Hormones)

48%

Good, 96%

Chlorate {Inorganic DBPs}

37%

Intermediate 75%

Small size, weak acid inorganic molecules

1,4 Dioxane (Misc}

100%

Intermediate 89%

Small size, uncharged, slightly polar and water soluble organic molecules

defined as an individual chemical occurring at quantifiable level, which represents certain physicochemical and biodegradable characteristics of trace constituents relevant to fate and transport during treatment. Indicators can be used to regularly validate treatment performance without the need to monitor al l chemicals of concern. Indicator chemicals in this project were selected considering percentage detection and concentration in secondary wastewater, and percentage removal by MF/RO treatment. Indicators were selected either to indicate specific performance of a treatment process or safety of the treated water: Treatment Performance Indicators have chemical or physical characteristics that can be linked to the removal mechanism and are present in wastewater at sufficiently high concentrations with sufficient frequency (typically >80% detection) to determine the degree of reduction through a process. The key properties for chemical rejection by MF/RO are size, hydrophobicity, polarity, acidic/basic character, and solubility in water. Recycled Water Quality Indicators demonstrate safety of the MF/RO treated water with respect to a group of compounds that share similar physical and chemical properties and provide additional confidence beyond treatment performance monitoring. They are particularly useful for chemical classes where no chemical was detected in wastewater with sufficient concentration or frequency to be used as a treatment performance indicator. The results from this project were analysed considering the characteristics of a good treatment performance indicator chemical to derive a group of indicators appropriate for monitoring chemical removal by MF/RO treatment.

56 SEPTEMBER 2010 water

Large size, polar organic molecules

Large size, uncharged, aromatic organic molecules that are capable of hydrogen bonding

Selected treatment performance indicators (Table 2) were normally detected in secondary wastewater more than 90% of the time. They were usually detected at higher concentrations than other chemicals of the same group. If more than one compound was commonly detected in secondary wastewater at similar concentrations, the one with the lower percentage of rejection was selected as it is considered more sensitive to assess the performance of the treatment. For each of the chemical classes studied, suitable recycled water quality indicator chemicals were also identified. In many cases, the best chemical indicator for recycled water quality was also a suitable treatment performance indicator. The chemicals chosen as recycled water quality indicators but were not included as treatment performance indicators are listed in Table 3. Both treatment performance and recycled water quality indicators have been recommended for use in the Water Corporation's Groundwater Replenishment Trial.

Conclusions The Water Corporation's Groundwater Replenishment Trial will treat wastewater with microfiltration (MF), reverse osmosis (RO) and ultraviolet light (UV) before injecting it into the Leederville aquifer, with re-extraction for drinking water planned for the future. The research carried out in the PCRP project has resulted in the development of reliable methods to characterise recycled water quality following secondary and MF/ RO treatment and has confirmed that MF/RO treatment reliably produces recycled water suitable for augmenting public drinking water supplies. Chemical contaminants were removed to levels below health significance and the water quality achieved after the MF/ RO treatment complied with the Australian

Drinking Water Guidelines (ADWG, 2004) and with the Australian Guidelines for Water Recycling: Augmentation of Drinking Water Supplies (AGWR, 2008), except occasionally for N-nitrosamines. Whi le not considered a significant health risk, N-nitrosamines including NOMA require further study, and this is on-going through regu lar monitoring during the Groundwater Replenishment Trial and through research studying N-nitrosami ne pre-treatment and formation currently being undertaken by the Curtin Water Quality Research Centre, funded by the Australian Research Council, t he Water Corporation and Water Quality Research Australia. The final PCRP project report provides the information necessary for WA government to develop regulation for conducting indirect potable reuse using MF/ RO t reatment, and includes health and environmental recommendations for the Groundwater Replenishment Trial. Th is research has indicated t hat there will be a high degree of safety associated with further investigation of indirect potable reuse in Western Australia when MF/RO t reatment is used in the t reatment train. Identification of key chemicals (indicators of treatment performance and recycled water quality) for monitoring, along with the implementation of a risk management framework , provides confidence to proceed with the Groundwater Replenishment Trial. Further information is available in the full technical report: Premier's Collaborative Research Program (2005-2008): "Characterising Treated Wastewater For Drinking Purposes Following Reverse Osmosis Treatment". Technical Report, Published by Department of Health, Western Australia ISBN 978-0-98074770-6. The report is available to download from: http://www.public.health.wa.gov.au/ 3/1117 /2/ groundwater_replenishment_ trial.pm

technical features


Acknowledgments This project was funded by the Prem ier's Collaborative Research Program (PCR P), a collaborative science program designed to encourage a range of Western Australian researchers to pool their knowledge and expertise.

The Authors Kathryn L Linge (email: k. linge@curtin.edu.au), Francesco Busetti, Cynthia Joll, Anna Heitz are at t he Curtin Water Quality Research Centre. Palenque Blair, Mark Handyside and Simon Higginson are with t he Water Corporation of Western Australia. Clemencia Rodriguez is with t he WA Department of Health, Justin Blythe is with KBR Pty Ltd , Melissa Bromley with the Department of Water, Oana Lord with the Nat ional Measurement Institute, Clare Newby with ChemCentre and Simon Toze with CSIRO, Land and Water.

References ADWG (2004) Australian Drinking Water Guidelines 6, Canberra, National Health and Medical Research Council, Nat ural Resource Management Ministerial Council. ADWG (2010) Draft Aust ralian Drinking Wat er Guidelines. National Health and Medical Research Council, Natural Resource Management Ministerial Council, Canberra. AGWR (2008) Australian Guidelines for Water Recycling: Managing Health and Environmental Risks. Augmentation of Drinking Water Supplies, Canberra, Environment Protection and Heritage Council, National Health and Medical Research Council, Natural Resource Management Ministerial Council. Busetti, F. & Heitz, A. (in press) Determination of human and veterinary antibiotics in indirect potable reuse systems. International Journal of Environmental Analytical Chemistry, accepted 9th December 2009. Busetti, F., Linge, K. L., Blythe, J. W. & Heitz, A. (2008) Rapid analysis of iodinated x-ray contrast media in secondary and tertiary treated wastewater by direct injection liquid chromatography-tandem mass spectrometry. Journal of Chromatography A, 1213, 200-208. Busetti, F., Linge, K. L. & Heitz, A. (2009) Analysis of pharmaceuticals in indirect potable reuse systems using solid-phase extraction and liquid chromatography-tandem mass spectrometry. Journal of Chromatography A, 1216, 5807-5818 Drewes, J. E., Sedlak, D., Snyder, S. & Dickenson, E. (2008) Development of Indicators and Surrogates for Chemical Contaminant Removal during Wastewater Treatment and Reclamation . WateReuse Foundation, Alexandria, WRF03-014. Eaton, A. D., Clesceri, L. S., Rice, E. W. & Greenberg, A. E. (Eds.) (2005) Standard methods for the examination of water and wastewater, Washington DC, American Public Health Association, American Water Works Association and Water Environment Federation. Fenech, M. (2007) Cytokinesis-block micronucleus cytome assay. Nature Protocols, 2, 1084-1104. PCRP (2009) Premier's Collaborative Research Program (2005-2008): "Characterising Treated Wastewater For Drinking Purposes Following Reverse Osmosis Treatment". Technical Report;. Department of Health, Western Australia, ISBN 978-0-9807477-0-6. Rodriguez, C., Lugg , R., Van Buynder, P. , Devine, B. , Cook, A. & Weinstein, P. (2010) Efficiency of RO for Removal of Chemical Contaminants. Water, 37, 64-68. Rodriguez, C., Weinstein, P., Cook, A., Devine, B. & Buynder, P. V. (2007) A proposed approach for the assessment of chemicals in indirect potable reuse schemes. J Toxicol Environ Health A, 70, 1654-1663. Standards Australia (1990) Test methods: guide to the format, style and content. Standards Australia, Sydney, AS 2929-1990 Standards Australia (2005) General requirements for the competence of testing and calibration laboratories. Standards Australia, Sydney, AS IS0/I EC 17025-2005. WHO (2008) Guidelines for drinking-water quality [electronic resource]: incorporating 1st and 2nd addenda, Vol.1, Recommendations, Geneva, World Health Organization. 3rd ed.

Sl'IIAUa tllllPls the ultimate pull-out resistant pipe joint for all metal pipes, plastic pipes or plastic to metal pipes.

8'l1IAUB-FLEX and 8TRAU8-0PEN-FLE are for all pipe materials and absorb noise, vibration, expansion and contraction.

SIRAUB,G CtMP is the ideal clamp for safe and reliable repair of damged pipes of any material.

Call KCES for further information: Phone: +61397283973 Fax: +61 3 9728 2973 Website: www.kces.com.au Email: info@kces.com .au

water

SEPTEMBER 2010 57


sustainability design for urban water

~]

refereed paper

DECENTRALISED DEVELOPMENT: THE ECOVILLAGE AT CURRUMBIN B Hood, E Gardner, R Barton, R Gardiner, C Beal, R Hyde, C Walton Abstract The Ecovillage at Currumbin is a 144 lot development in the Gold Coast hinterland wh ich employs a range of strategies to enhance the sustainability of the community. All the water was supplied by a combination of large (2: 20 kl) rainwater t anks and recycled water from a clusterscale sewage treatment/water reclamation plant. Despite the high specific energy use of the household scale rainwater pumps, the overall household electricity use was less than a third of that of an average Qld home. This factor reduced to a sixth when total energy (electricity and gas) was compared between housing types Energy use of the sewage treatment and reclamation plant was ~ 1.1 kWh/kl , less than that of an equivalent centralised plant (e.g. Pimpama Coomera) reflecting the low energy systems used to reduce organic load (septic tanks, recirculating texti le filter). With some minor optimisation , we believe the Ecovillage could be the first mainstream energy and water neutral community in Australia

Introduction Decentralised technologies are an increasingly popular option for developments w hich cannot easily be connected to traditional water (and sewerage) services, or which promote sustainability and self sufficiency as a unique marketing feature. Whilst it is unlikely that decentralised developments can be "carbon copied" into mainstream urban development, many of their features such as rainwater tanks, water recycling, solar hot water systems and energy efficient housing construction are replicable. However it is important to separate often wel l-meaning sustainability claims from biophysical fact, if we are t o move forward with confidence in arguing for a re-engineering of the water cycle of future urban developments. Thus, studies of the wat er This is an edited version of the presentation at Ozwater'10.

58 SEPTEMBER 2010 water

Typical pedestrian friendly layout of The Ecovillage homes showing high communal open space with quality landscaping, climate adaptive housing and rainwater tanks. and energy consumption of the Sustainable House in Sydney (Michael Mobbs), Healthy Home on the Gold Coast (Gardner et al., 2003) Research House in Rockhampton Qld. (Kele et al. , 2006), and a cluster of houses at Silva Park (Beal et al., 2008) have all been important for informing the debate on sustainable housing. The most recent opportunity for scrutiny of the water/energy nexus is The Ecovillage at Currumbin (Qld), where the water supply and wastewater treatment services for 144 lots are wholly provided on site. Potable water is supplied by individual household rainwater tanks (20-45kL) whilst a communal sewage treatment/water reclamation plant (based on membrane filtration and UV disinfection) supplies non-potable wat er for toilet flushing, external household use and public open space irrigat ion. The water and energy consumptions are monitored at the development using a sophisticated installation of water and energy meters, most of which are networked to a central data server.

Materials and Methods The Ecovillage at Currumbin is a development in the Gold Coast hinterland which employs a range of strategies t o enhance the sustai nability of the community. The 110 hectare site has

been planned for 144 allotments, on which 40 houses have been constructed and occupied, some since 2008 (See Beal et al, 2008). A previous paper, (Lane and Gardner, 2009), has reported on Life Cycle Assessment of the decentralised technologies used. The occupied residences studied in this report are a mixture of 1, 2 and 3 bedroom detached houses on community title blocks that vary in size from 400 1400 square metres. Housing design at The Ecovillage is cli mate adaptive and energy efficient with appliances like air conditioning and electric clothes dryers not permitted. To ensure comp liance with a stated commitment to sustainability for the entire development, an extensive set of building guidelines stipulat e the specification of materials, fixtures and fittings, and all designs must be approved by the Body Corporate prior to commencement of construction . The site is not connected to water or sewerage mains, and all water services are supplied on site. 109 of the blocks are connected by a sewer network and

the energy and water balances have been monitored and found to be almost neutral.

technical features


1 ·~

sustainability design for urban water

ref ereed paper

recycled water treatment plant that provides reticulated Class A + recycled wat er to the residences for toilet flushing and external amenity use. Any excess recycled water is used for irrigation of common property through a zoned irrigation system. An onsite groundwater bore from a shallow aquifer also provides water for public open space irrigation. Each residence catches and stores rai nwater which is used for all household potable purposes. Minimum vol umes of the tank storage are stipulated in the Ecovillage Architectural and Landscape Code as described in Table 1, and these minimums can be met by any configuration of tank sizes. The tanks are all above ground t o minimise disturbance of the soil and water table on the site. Electric pumps provide the flows for the systems. 5000 litres of storage is also stipulated for fire fighting purposes at each home, and th is can be incorporated in the main storage, or within a dedicated tank. This extra storage complements the recycled water main which handles firefighting flows that fulfil state guidelines on fire protection. Gas boosted solar hot water systems are specified for all houses. Each house has at least 1kW of grid connected photovoltaic generation capacity. The flows of rainwater, recyc led water and hot wat er were monitored by staff from Qld Department of Environment and Resource Management (DERM) on a monthly basis, by manual readings of the appropriate meters. Gas meters and energy meters for lights, rainwater pumping, general power outlets and photovoltaic generation were also read manually at the same time. All of these meters also connect to an integrated monitoring system (Ecovision) with a display on an internal screen in each house, which was installed under body corporate rules. Monitoring of houses at

200

Results and Discussion

Table 1. Minimum rainwater storage volume requirements at the Ecovillage at Currumbin. Lot type

Minimum storage volume

Household water use The average household water use at The Ecovillage is 196 Uperson/day as shown in Figure 1, wh ich seems quite high in comparison to reported consumption figures in the reg ion. For example in 2008/09 the Gold Coast average is 185 Up/ d and a development at Pimpama Coomera, which has dual reticulation, used 156 Up/d (Willis et al. , 2009). In comparison Central South East Queensland (CSEQ) has a consumption of 134 Up/ d in 2008/ 09, wh ilst the decentralised development in western Brisbane, Silva Park, had a consumption of 121 Up/ day. This wide variety of figures is primarily a result of differing water restrictions in each of the regions. Central SEQ, which includes Brisbane, has been on Level 6 restrictions for most of the period, which has precluded almost all outside use of mains water. The Gold Coast had much lower restrictions over the same period and this is shown by the increase of the figures at these locations. The Ecovillage, being completely independent of the mains, has no restrictions and the residents utilise this freedom to irrigate the extensive vegetable gardens at almost every residence.

Stormwater detention gap

1 bedroom

22.5 kl

2.5 kl

2 bedroom

33. 75 kl

3.5 kl

3 + bedroom

44.5 kl

4.5kl

The Ecovillage began in Apri l 2008 and each house completed since has been added to the monitoring regime. Al l data for each parameter reported in this study is collected from houses that have readings that cover at least 90 days of occupation. Data collected from a com plementary st udy (Silva Park) covers the period from December 2005 to November 2009. Silva Park is a 22 lot eco-friendly development in Brisbane where individual household rainwater and greywater systems reduce import/export of potable water/sewage respectively ( Beal et al 2008, Gard ner et al 2008). Individual household rainwater tanks (22KL) are connected to a large (150KL) communal tank which stores surplus water in wet weather and supplies potable water in extended dry periods. The commu nal tan k in tu rn is connected to council mains water via a trickle top up supply. All internal water used by the homes is sourced from the rainwater tanks. All the tankwater is UV disinfected before use. Other features of Silva Park include individual greywater systems which subsurface irrigate a dedicated grassed area, with diversion to a local sewer system during extended wet weather. All toilet waste goes to this sewer, which only discharges into the council sewer during off peak times. For this analysis only 6 homes were available for mass balance studies.

This increased external water use illustrated in Figure 2, shows The Ecovillage uses more than double the water of other reported values in SEQ. All of the water used externally at the Ecovillage is recycled water from the treatment plant on t he site and is reticulated to the individual residences. This recycled water, therefore , is serving the dual function of improving amenity of the community by allowing unrestricted external use, and the second fu nction of preventing the disposal of treated wastewater to waterways (or ground water) , as in traditional systems.

m

140

"'

110

"'

! ~ t "·

120 100

L.

1. .

115

.,

"

~

!1 140

IJ '° 134

J

!

- ~I121

120

100

Eco,,H'*Of

G06cl CONt

S~va Pe,ik

c u ,tral SEQ

SEO tarS-t

Figure 1. Total water use per person for The Ecovillage houses compared with similar data for other developments in the region. Also shown is the QWC target for SEQ after water restrictions are lifted.

40

"

20

Internal Slh'• Patk

Figure 2. The comparison of internal and external water use at three decentralised developments in SEQ.

water SEPTEMBER 2010 59


~

sustainability design for urban water The Pimpama Coomera development also has dual reticulation, however, the system had not been switched to recycled water at the time of writing and the lower external usage may also reflect the impact of the use of rainwater tanks at this development for external irrigation. Further, promotion of the uses of recycled water had not been c onducted in the community, so these val ues may reflect compli ance with general restrictions in the area as reported by Wil lis et al., (2009). The flows of rainwater were not monitored at t his site. The figure at Silva Park includes data from December 2005 to November 2009, when lower levels of restrictions were in place. High usage at The Ecovillage may also reflect significant volumes of recycled water being used for construction purposes, establishment of gardens and landscaping features in t his new development. Leakage of the recycled water connection points have also been noticed in a small number of occupied homes, and have been remedied as they occur by homeowners and Ecovillage staff. The val ue for internal water use at The Ecovillage shown in Figure 2, includes 20 Up/ d for t oilet flushing that is provided by recycled wat er. When indoor water use is compared with studies in other areas such as Yarra Valley (Roberts, 2005) or Perth (Loh and Coughlan, 2003), the Ecovillage is wel l in front at 115Up/d compared to 169 Up/d and 155 Up/d respectively. Locally, the contemporary study of Willis et al., 2009 at Pimpama Coomera reports a higher value of 133 Up/d. These comparisons show that the residents of the Ecovillage are comm itted to conserving water resources, particularly inside the home. Water efficient appliances and fixtures such as t aps, shower roses and washing machines are mandated by The Ecovillage Architectural and Landscape Code. The low value of 89 Up/d at Silva Park reflects the low rainfal l years of 2006 and 2007 as shown in Table 2, and the tight water restrictions for 2008, and for most of 2009. All of the consumption figures, however, fall within the Queensland Water Commission's long term target which was revised from 230 Up/d to 200 Up/ d in November 2009. The adoption of decentralised technologies such as rainwater tanks and decentralised scale recycling systems appears to show the way forward for incorporation into urban systems of t he futu re. The important factor is the will ingness of developers to

60 SEPTEMBER 2010 water

refereed p a p e r

Table 2. Annual rainfall (mm) at weather stations near The Ecovillage and Silva Park. Location

The Ecovillage Silva Park

2006 1740 686

2007

2008

1140 853

1791 1234

consider the use of alternative sources of water for different purposes in the home, and to plan accordingly. The tank volumes at The Ecovillage and Silva Park {15 - 45kl} are much larger than the currently "mandated" 5k l tanks for new homes, to reflect the utilisation of t he rainwat er in the residence for all end uses. Therefore these tanks easily meet the expected 70 kUh h/yr target saving as stipulated in MP4.2 (DIP, 2008) . Median lot sizes at these developments, at 930 m2 and 1100 m 2 respectively, although larger than the average urban lot, are still within the upper ranges of urban developments. Pimpama Coomera for example has a median lot size of 628 m2 but in general only has 5 kl tanks on a proportion of houses that were constructed after January 2007. Another important factor for rainwater collection is t he connected roof area to ensure the tan ks are adequat ely replenished during a variety of rain events. The Ecovillage homes have a median roof area of 142 m2 and th e Silva Park Homes 262m 2 which compare to the Queensland average for new houses of 236 m2 (DEWHA, 2008). The inclusion of above ground tank storages has not adversely affected the amenity or aesthetic of the residences at these locations. The breakdown of water source at Th e Ecovillage shows that 48% of the residents' water was sourced from rainwater with the remainder sourced from recycled water, compared to Silva Park with 82% of the total collected from rainwater. The total at Silva Park includes

Table 3. The recycled water balance of The Ecovillage. Sewage inflow Residential demand for RW* Public open space irrigation Reticulation leakage losses Total output RW (includes Bore) Bore augmentation for POS Irrigation area Application Rate POS*

13.4 kUd 9.3 kUd 18.3 kUd 2.2 kUd 29.8 kUd 16.4 kUd 7 ha POS** 0.95 MUha/yr

â&#x20AC;˘â&#x20AC;˘ Public Open Space Irrigation for nursery, greenways & cropping * Recycled Water

(exc Dec)

2009

Long Term Ave

1438 1201

1491 1175

Coolangatta Airport Enoggera Reservoir

periods of drought during 2007, and the latter part of 2009. The supply shortfall at Silva Park was made up by mains water that is connected to the communal st orage tank (Beal et al., 2008). Total hot water use was measured at The Ecovillage and Silva Park, and val ues of 42 Up/d and 41 Up/ d respectively were recorded over the corresponding periods. These val ues represent 36% and 46% of internal water use at the developments, and have substantial implications to energy use by houses.

Sewage and recycled wate r The treatment and reuse of sewage at The Ecovillage is an important strategy in meeting the needs of the individual households, and the community as a whole. The recycled water treatment plant is regarded as a low energy plant, utilising septic tan ks for primary treatment, oxidation by attached growth textile filter, and membrane fi ltration and ultraviolet sterilisation for final polishing . The sewerage reticulation network feeding thi s fac ility is largely gravity driven, further reducing energy requirements of the system. Recycled water is used in a number of applications where the use of high quality potable wat er is not necessary. The applications include toilet flushin g, household irrigation, communal open space irrigation, plant nursery irrigation, cro p irrigation and some usage in construction. To ensure contin uity of supply to the resident s and a substantial safety factor in the event of treatment system failure , 1 ML of buffering capacity and three 75 kl recycled water storage tan ks are incorporated into the treatment facility. The figures in Table 3 show that the volume of sewage recyc led, 13.4 kl /d, is greater t han the recycled water demand at the residences, 9.3 kUd, so the residents' recycled water demand can be met without any addition from supplementary supply from groundwater. This excess recyc led water is presently being augmented by groundwater for the irrigation requirements of extensive communal space (7 ha). Th ere were also reticulation losses of 2.2 kUd ay which have since been subst antially reduced.

technical features


l\J

ref ereed paper

T he specific energy of the recycled water at The Ecovillage, 1.1 kWh/ Kl, compares favourably with the specific energy of the Gold Coast recycled water, 1.4 kWh/kl, inclusive of energy for membrane filtrat ion and ultraviolet sterilisation (Kenway, 2008). This energy density also compares favou rably with a traditional municipal design, because nitrogen is not reduced in t he Ecovillage treatment process. It warrants not ing that the figure for The Ecovi llage includes the energy for pumping a further 16kU day from t he bore pl us t he energy for pumping over 18 kUday water for irrigation of public open space If t his extra energy were removed from the calculations t he specific energy would d ecrease substantially, adding to the attraction of using this t ype of low energy treatment system in other developme nts. The use of 14 kW of roof mounted solar power panels to offset the electricity used by the plant (15 kWh/day) is f urther commitment by t he developers to improving the sustainability of t he Ecovillage. At present, the ability t o monitor separate components of t he energy usage at t he plant is not in place. However, a study being undertaken by the Urban Research Water All iance (http://www.urbanwateral liance.org.au/) is currently underway t o fill t his knowledge gap.

Recycled Water Quality The quality of t he recycled water at the Ecovillage is monitored as part of t he licensing conditions, and t he average results listed in Table 4 show that the recycled water treatment plant complies easily with the license conditions. The electrical cond uctivity, 634 ÂľScm-1, and the sodium absorption ratio (SAR) at 3.8 were recorded from supplementary monitoring by DERM staff. This water quality was attained through the use of rainwater as the principal water supply at t he Ecovillage. Rainwater has very low conductivity and mineral loads and just t he usual addition of salts by residents is reflected in the recycled water quality. The recycled water quality at t he Ecovillage would be similar to or better than that expected from a municipal treatment plant, especially those influenced by moderate potable wat er salinity (e.g. 350mg/ L from Wivenhoe) or saline groundwater ingress into the sewerage system (e.g. Luggage Point).

sustainability design for urban water Table 4. Water Quality test results for The Ecovillage recycled water. Parameter

Units

Turbidity

NTU

Ecovillage (average)

pH

The energy to move wat er over the short dist ances that are found in decentralised

Testing Frequency

0.3

< 2.0

Continuous

7.0

6.0 - 8.5

Weekly

Free Cl2

mg/L

1.4

> 1.0

Daily

Total Nitrogen

mg/L

12.5

< 15 (45 max)

Monthly

Total Phosphorus

mg/L

2.9

< 10 (30 max)

Monthly

Dissolved 02

mg/L

7.3

> 2.0

Weekly

BOD

mg/L

<3

< 10 (30 max)

Monthly

mg/L

<2

< 10 (30 max)

Monthly

cfu/100ml

<1

< 10

Weekly

Suspended solids E.coli

Table 5. Household rainwater systems specifications. Average Pump Power Watts

Pressure Vessels/Houses

UV

Ecovillage

700

6/33

No

Silva Park

630

0/6

40W

ISF

890

2/4

No

systems is reported in Figure 3, and compares t he energy requi red to supply a unit volume (1 kl) at each house. Rainwat er pumps at The Ecovil lage have a median value of 1.4 kWh/kl which compares favourably with the other decentralised systems reported of 1.8 kWh/kl at Silva Park and 1.5 kWh/kl reported by t he Institute for Sustainable Futures (ISF) (Retamal et al. , 2009) for a number of residences in the Sydney regio n. The two values for Silva Park (1.8 and 5.1 kWh/k l) show t he energy used by the system with and without ultraviolet sterilisation. Table 5 shows that t he average pump sizes at these three systems are all less than 1kW. The decentralised systems when compared to t raditional systems such as t he Gold Coast potable supply are at an energy disadvantage. However when compared to the individual specific energies of systems such as the Purified Recycled Water (PRW) scheme and t he seawater desalination plant at Tugun, the u

decentralised figures once again look favourable. When the projected contributions of these new water sources are factored into the regional municipal water supply, a value of 1 .2 kWh/ kl is estimated for potable water supply across the region (Claydon, 2008), and systems such as The Ecovillage again look comparable. In future, such systems should provide an attractive sol ution for urban developments where centralised water and sewerage infrastructure can be supplemented by su itable decentralised t echnologies. Further opportunities also exist to improve the specific energy of decentralised systems, through optimisation of system design and components. Studies by Cunio and Sproul (2009) show that specific energies of rainwater pumps can be reduced to as low as 0.1 kWh/ kl using 12 V DC pumps in low f low applications like toilet cistern

- -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

L.o

5.1

5.0

go

i ;

15. 4,0

~ 3.0

e

1 i

- - - 1.ll - - -

2.0

2.0

2.0

1.4

1.2

1.0

1.0

U)

Ecovlllage

Silva Park

Sliva Park no

UV

Specific energy of rainwater pumping

Licence

ISF

Gold Coast

Potablo

PRW

Tugun Desa i

SEQ projection 2012

Figure 3. Comparison of specific energy for rainwater pumping with centralised municipal supply options.

water SEPTEMBER 2010 61


sustainability design for urban water valves. Retamal et a/. (2009) also demonstrated the value of pressure vessels which reduced the energy consumption by a third for water supply systems supplying toilets, laundry and external taps. The pressure vessels reduced the number of pump starts per litre supplied noting that high transient energy use peaks occur during a "start up".

refereed paper

Houaohoki olec:tricity uao 9000 7882

8000 ,

t

7000

6907

~ BOOO

!!',; BOOO

Looo

i

3000

W 2000

- -

- - -1680 - - - -

1000

Electrical Energy The electrical energy consumption of the residents of The Ecovillage, as shown in Figure 4 is very low at a median of 2094 kWh/hh/yr in comparison to either Silva Park (6907 kWh/hh/yr) or SEQ (7882 kWh/hh/yr).

Silva Park

SP no NCâ&#x20AC;˘

Ecovlllage

Ecovlllage

w¡

SEQ

SEQ no NC ¡

Figure 4. Household electricity use for The Ecovillage compared with similar data for other developments and regions * Air Conditioning, ** Photovoltaic generation. disturbance to wildlife. The average value for lighting energy in Queensland is 973 kWh/hh/yr (M ills, 2009) but this figure includes incandescent and inefficient halogen lights, prohibited from sale after November 2009. Compact building sizes at the Ecovillage also contributes to the lower lighting energy needs with average house sizes of 155 m 2 , compared with SEQ averages of 236 m 2 .

The principal energy saving strategies at The Ecovillage are set out clearly in the local community title documents and design guidelines which are distributed to new landholders. These codes specify the design of the building shell and choice of appliances for the owner. The first strategy that impacts the energy consumption is the banning of air conditioners at the site. Thermal comfort however is not abandoned by this practice as many other regulations in the code address the issue. Insulation, thermal mass, building orientation, shading of openings, cross ventilation and convection ventilation are all stipulated in the package. Often these codes have subsidiary benefits to other aspects of the energy consumption of the house such as lighting energy.

Although rai nwater systems utilise inefficient pumps for transferring water, pumping energy is a small proportion of the total electricity consumption of a household. Pumping energy at The Ecovillage is a median 87 kWh/hh/yr, or 4% of the total household electricity consumption. Silva Park is higher at 666 kWh/hh/yr (or 10%) due to the use of ultraviolet sterilisation in the rainwater system.

Energy for lighting is measured separately at the Ecovillage and a median value of 145kWh/hh/yr was recorded. The use of natural lighting and energy efficient compact fluorescent light are mandated at the site and help deliver the low lighting energy consumption at the site. Dark sky policies also minimise unnecessary external lighting to reduce energy use, neighbourhood impacts and

The remainder of the electrical energy (1862 kWh/h h/yr) consumed at the Ecovillage is used by plug-in appliances. The local design codes encourage the use of efficient low energy appliances wherever possible, however a "grandfather" clause in the documentation allows the use of existing appliances until they are replaced. The major fixed appliances in each house, the

Theoretical Ecovillage Electricity Breakdown 12103 kWh/hh/yr) Wasn~g Mac/line, 157

[SJ

oven and cook top, are gas appliances and the hot water system is a gasboosted solar system. Electric clothes dryers are banned, and dishwashers are discouraged. Hence comparing electricity consumption with the surrounding region is difficult without adjustment to compensate for varying technology. Figure 5 shows the theoretical set of standard appliances in Ecovillage houses compared to the reported averages of SEQ houses. The SEQ household data has been normalised by adjusting for household population density to 2.3 p/hh, equivalent to the Ecovillage. Average energy consumption figures were obtained for types and densities of appliances used in SEQ homes and these figures were then applied t o a minimal set of the same appliances at The Ecovillage. The comparison shows that significant savings can be obtained using st andard appliances (i.e. not necessarily the most energy efficient) at an easily attainable density. For example, televisions at the Old density of 2.4 units/hh means that there are more televisions than residents in the house at the Ecovillage, so the theoretical figure for Currumbin shows the energy consumption for a single television. When the theoretical figures of total appliance

Typical SEQ Electricity Breakdown (4585 kWh/hhlyr)

Small Miscellaneous,

150

C~uler, 133

Refr~eralor, 436

Figure 5. Partitioning of predicted electricity use at an Ecovillage home with an average home in Queensland. (data adapted from Mills 2009 and Newton and Tucker, 2009). 62 SEPTEMBER 2010 water

technical features


energy consumption (2023 kWh/hh/yr) in Figure 5 are compared with the measured val ue at the Ecovillage (1862 kWh/hh/yr), the comparison highlights the approach of consciously choosing energy saving appliances, and using all appliances frugally, substantial savings in energy usage can easily be obtained. The greatest savings are gained by the elimination of gross energy-using appliances, such as air conditioning. However, useful but incremental gains can be obtained by reducing the numbers of other appliances such as televisions or home entertainments systems. Importantly the lifestyle of the residents does not need to change greatly, as all appliance types are represented with the few exceptions of air conditioning and clothes dryers. The other important contribution to the low value in the Ecovillage is the awareness of the residents of their own power use. Each house is fitted with a central monitoring system (Ecovision) that allows the consumers to see an actual value of energy or water use in real time. This allows the resident to actively manage their appliance usage and control their energy usage. The Ecovillage has employed one last strat egy to ensure that electrical energy usage is sustainable. Each residence has at least 1kW of roof mounted photovoltaic generation capacity mandated by the local development code. These solar panels are grid-connected to offset household electricity usage. The median generation val ue recorded was 1580 kWh/hh/yr (Figure 4) or 75% of the total electrical consumption. We believe this figure could easily be revised upwards if generation capacity were sized more closely to household size (similar to the rainwater tank sizing at the Ecovillage) as the generation to consumption rat ios ranged from 0.2 to 1.8. LPG consumption The other energy source at The Ecovillage is liquefied petroleum gas (LPG) which provides energy for cooking and boosting the solar hot water system. Cooking included cooktops and ovens (and barbeques) and these uses would be expected to be the major end uses of LPG at the site. The gas is measured by a standard gas meter at each house but individual appliances are not measured separately. The results show a median Ecovillage consu mption of 5309 MJ/hh/yr which is of a similar magnitude to the LPG consumption at Silva Park of 6050 MJ/hh/yr, which is surprising as the households at Silva Park use gas for both t he cooktop only and for heating all of the hot water using an instantaneous hot water systems. The average consumption for Queensland homes using gas for water heating, cooki ng and space heating is 14400 MJ/hh/yr (Mills, 2009). Analysis of this data shows that gas used for cooki ng can be estimated as 3300 MJ/hh/yr leaving a residual of 2000 MJ/hh/yr for boosting hot water systems at The Ecovillage. Applying this figure to the measured volume of hot water used at the Ecovillage shows solar boosting efficiency of only 43% compared to the 86% expected for SEQ (Mills, 2009). Direct cont act with the residents has established that in several installations at the site, the solar hot water systems had been incorrectly installed, and hence gas boosting was dominant. Water temperature temperi ng valves had been incorrectly inst alled prior to the gas booster and the water, t empered to 45°C, was being subsequently heated to 60°C by gas boosting, increasing the consumption of gas unnecessarily. This highlights the necessity for tradespeople to be trained in the installation of all of the alternative technologies that are utilised in this type of development. Professional building

Leading the world in the modernisation of Irrigation Infrastructure Rubicon is leading the world in the modernisation of irrigation systems. Total Channel Control(!) technology has set a new International benchmark of 90% distribution efficiency. The FlumeGate'" is the cornerstone of TCCI!> and provides accurate flow measurement and control. Rubicon has worked with the University of Melbourne for over 10 years pioneering innovative approaches to water delivery technology. Rubicon is Motorola's Distribution Partner, offering MOSCAD and ACE RTU solutions for management and control of Water and Wastewater for urban and rural Utilities. • • • • •

SCADAConnecf" FlumeGate'" SlipGate'" SolarDrive'" Total Channel Control<!> (TCC)I!> • FarmConnect'" • Australian Premier Distributor for Motorola MOSCAD and ACE.

,;;:=.

--

RUBICON www.rubicon .com.au Rubicon Systems Australia Pty Ltd 1 Cato Street Hawthorn East VIC 3123 Australia Telephone +61 3 9832 3000

1A Wheeler Street Shepparton VIC 3630 Australia Telephone +61 3 5820 8800 www.rubicon.com.au


sustainability design for urban water Comparative onorgy uso

-

-----------------------

40

____________________ _, ________ _

refereed paper

Comparative C02-e of total energy

10000

q

[s]

----------9000 8000

35

f 30

- - - - - - - - - - - - - - - - - _____________ .

144 7000

- - - - - - - - - - - - - - - - - - - - -

8.1

€ ~25 0

~

~ 15

cGas

DGas

~

'20

1197

DElectrlcity

c E1ectricll

7113

- - - - - - - - - - - - - - - - - - - - -

3000

24.9 5.3

10

53

2000 1000

76

---------

21153

-----

511 Ecovillage Net

EcoviUage

Silva Park

SEO

Figure 6. The total household energy consumption of The Ecovillage compared with Silva Park and SEQ. certifiers at both the development level and local government level need to be able to recognise faults of this type and report shortcomings, particularly if fixtures have been specifically installed to provide energy savings. The overall energy consumption which combines electricity and LPG expressed as GJ/hh/yr are shown in Figure 6. The Ecovillage returns the low val ue of 13 GJ/hh/yr of total consumption, or 7 GJ/hh/yr when solar electricity

Eco>Jllage Net

ECO'Jllage

Silw Park

SEQ

Figure 7. The household greenhouse gas generation of the Ecovillage compared with Silva Park and SEQ.

generation is factored in t o the value. This is much lower than Silva Park and SEQ values of 31 GJ/ hh/yr and 43 GJ/hh/yr respectively. The figure for Silva Park shows a good improvement on the average Queensland value and is an indication that even small gains can be made with only small changes in infrastructure design. These residences are much closer to the Queensland median in terms of size and appointment. However the residences at

The Ecovillage being smaller, with carefully designed building shells and well selected appliances, display t he greatest gain in this study, using less than a sixth of the energy of their counterparts in the broader community. Even greater environmental gains are evident when the environmental implications of the energy consumption is expressed as kg of COr equivalent as shown in Figure 7.

Just like our planet, we live for water. ALS Water Resources Group offers a leading range of chemical, biological and microbiological testing solutions to the greater water industry, including: Drinking/Potable Water • Catchment Management/Water Resource • Desalination • Waste Water Treatment/Industrial Water

• Recycled Water • General Water Quality Monitoring • Trade Waste • Sampling of Catchment/Drinking Water

Drink it in. Visit www.alsglobal.com or call 1300 32 69 47 to get started. ~

V

All ALS WRG laboratories are ISO 1702S (NATA) accredited to ensure laboratory results meet the highest standa rds. ALS also employs multiple layers of data verification to ensure its accuracy.


The net value of greenhouse gas generated at The Ecovillage at 857 kg COre/hh/yr is over ten times less t han the Queensland average of 9138 kg COre/hh/yr. This shows the clear advantage of photovoltaic generation compared to coal-based electrical generation that supplies most of Queensland electricity. The greenhouse gas density for coal generated elect ricity in Queensland of 0.3 kg COre/MJ is far greater than the 0.07 kg COre/MJ for LPG or the 0.06 kg COre/MJ for natural gas.

"Creating a Storm: The Future of Stormwater in Australia"

In a political anq economic climate where carbon-based power generat ion is increasingly being impost ed by reg ulat ion or financial penalties, renewable sources of power generation such as solar generation wil l become very attractive to the home owners of the future. The goal for future development could be carbon neutrality (e.g. Newton and Tucker, 2009) and The Ecovillage is demonstrating some of the methods that can be utilised to attain this goal. With just a little optimisation of t he systems, t he Ecovil lage itself is not far from this goal.

Conclusion The preceding discussion has show that the range of technologies employed at The Ecovill age at Currum bin have had a significant impact on improving the sustainability of the development. These tech nologies are not new nor untested met hods, but rather robust technologies used in combi nation to achieve beneficial outcomes. In t he sub-tropical climate of South East Queensland rainwater tanks and recycled water used together can comfortably meet the needs of the residents without restriction, and easily comply wit h t he usage targets of the regional authorities. Local energy consumption and generation has been wel l plan ned and t he use of solar energy in two of t he systems, water heat ing and electricity generation, has reduced the GHG production by a substantial amount. Importantly t he residents' lifestyles have been minimally impacted by the reduction and type of energy using appliances within t he household. Th is development could well provide a benchmark for urban development in the future. This type of master planned development co uld be scaled to suit cluster scale development thro ughout the region and wou ld suit both greenfield development and infill clusters. Moreover some of the t echnologies could be applied to high density development to reduce t he need to upgrade or install increased capacity of centralised infrastruct ure such as water supply or power generation. Further research is recommended that examines environmental, economic and social outcomes that were not discussed in t his study, particularly considering t he expected increase in population in SEQ and other regions in the future. These prelim inary results demonstrate t hat decentralised systems can compete favourably with centralised services in several aspects, and should provide a viable addition for water infrastructure for t he continu ing population expansion in SEQ which is expected to require 745,000 new dwellings by 2031 (SEQ Regional Plan http://www.dip.qld.gov.au/reg ional-planning/regional-plan2009-2031.ht ml).

National Conference of the Stormwater Industry Association Securing and diversifying the Nation's water supplies now and into the future, is a central element of building a sustainable Australia - and effective stormwater management wi ll play an important part in that future. The first National Conference of the Stormwater Industry Association will attract delegates from both Australia and overseas who will come together to hear more than 80 industry experts talk about the latest research in stormwater management and provide fresh perspectives that will be invaluable in achieving your water management objectives. Stormwater 201 0 will include a day of hands on workshops, three days of conference sessions and a final technical tour day visiting some key stormwater projects in Sydney.

Stormwater 2010 Don't miss the major Stormwater event to be held in Australia this year. For further information: GEMS Event Management

Phone: 02 9744 5252 Fax: 02 9747 8366 jmcgraw@gemspl.com.au www.gemsevents.eom.au/stormwater2010

Acknowledgments The authors would like to than k the management and staff of Landmatters for t heir cooperation and assistance with providing access and information for t his project.

Pfaffnum Spooscr

Gold $/)oils«

. Hmnes

w -

CIMU.

_.....__

Gold $/)oils«

~

..,

•BMT WBM

Silver Spooscr

Silver Spooscr

~

!P. . ....... CT8020

The authors would also like to thank Gold Coast City Council for the contribut ion of water meters to The

water SEPTEMBER 2010 65


sustainability design for urban water Ecovillage. The authors would especially like to thank the residents of The Ecovillage for allowing access to their homes for readings and the occasional cu p of tea.

Ryan Barton and Richard Gardiner are a scientist and tech nician respectively in DERM. Dr Cara Beal ( formerly a DERM scientist) is now a Research Fellow at Griffith University.

The Authors

Richard Hyde is a Professor of Arch itectural Science in the Faculty of Arch itecture, Design & Planning, University of Sydney, and Chris Walton is a Director of Land Matters P/ L, the developer of The Ecovi llage at Currumbin.

At the time of writing, Barry Hood was the scientist in charge of The Ecovi llage project. He is currently the Technical and Design Manager of GBG Wastewater Management P/L.

EA {Ted) Gardner is the Princi pal Scientist (email ted .gardner@ derm.qld.gov.au) of the Urban Wat er Cycle Science unit in the Department of Environment and Resource Management (DERM), Queensland. and an Adjunct Professor at the Queensland University of Technology.

References Beal, C., Hood, B., Gardner, T., Lane, J. and Christiansen, C. 2008. Energy and water metabolism of a sustainable subdivision in south east Queensland: A reality check. Presented at Enviro'08. Melbourne Exhibition and Convention Centre, 5-7 May 2008. Beal C, Gardner T, Ahmed W, Walton C, Hamlyn Harris D (2008) Urine Separation and Reuse Trial. Water Vol 35, No 1. pp 66-69. Cunio L. and Sproul A. 2009. Low energy pumping systems for rainwater tanks. Paper presented to The Solar 09 47th ANZSES annual conference. Townsville Australia. DEWHA, 2008. Energy use in the Australian residential sector 1986 - 2020 Department of environment, water, heritage and the arts (2008) p89, Appendix F, and Appendix H. Gardner, E.A., Beal, C., Lane, J., Hyde, R., Hamlyn-Harris, D., Skoien, P. and Walton, C. (2008) Measuring the metabolism of

ref e reed p a p e r

decentralised urban developments - do they demonstrate increased urban sustainability? Presented at IWA World Water Congress, Vienna. September 2008. Kele B., Hoffman K. , Orr N., Wolfs P. , Tomlinson I. and Midmore D.J. 2006. Water and Energy Requirements at a Tenanted Research House, Water Vol. 33, No 1. pp. 57-61. Kenway S., Priest ley A. , Cook S., Seo S., Inman I., Gregory M. and Hall M. 2008. Energy Use in the Provision and Consumption of Urban Water in Australia and New Zealand. Water Services Association of Australia, CSIRO, Melbourne. Lane J , Gardner E. 2009. Life Cycle Assessment of Water Cycle Alternatives. Water Vol 36, No.6. pp 88-94 Mills, D., 2009. Greenhouse gas emissions from energy use in Queensland homes Sustainability Innovation Division p9, 17, 20, 80. Newton, P. W., and Tucker, S. N., 2009. Hybrid buildings: pathways for greenhouse gas mitigation in the housing sector Institute for Social Research, Swinburne University of Technology, Melbourne, p56-59. Retamal M. , Turner A. and White S. 2009. Energy implications of household rainwater syst ems, Water, December 2009 (in press) Australian Water Association. Willis R. , Stewart R., Chen L. and Rutherford L. 2009. Water end use consumption analysis study into Gold Coast dual reticulated households pilot, Paper presented at Ozwater 09 Conference, 15 - 19 March 2009, Melbourne Australia.

For information on how Merck can assist you with products for your water testing contact us on Ph: 1800 335 571 www.merck-chem icals.com.au

What's important when testing key parameters in wastewater or drinking water?

Accu racy, relia bility, ease of ana lysis ... the peace of mind tha t comes from knowing you r results are correct. That's what's in it for you. Merck Chemicals.

I

I

,MERCK I I


•,]

refereed paper

sustainability design for urban water

SUSTAINABILITY COMPARISON OF THIRD-PIPE AND SEAWATER DESALINATION SYSTEMS IN WESTERN AUSTRALIA M Anda, N Hodgson, S Dallas Abstract Sustainability criteria are increasingly being applied to decision-making processes about future water source options. However, existing sustainability frameworks within the water services industry, for example from WSAA (2008) and IWA (Ashley et al. 2004) do not easily allow for the comparison of the range of different water source options (such as desalination and third-pipe reuse systems) at the scale of the entire urban water system. This paper presents the findings of a study commissioned by the Western Australian Department of Water that applied a sustainability assessment framework to make a preliminary com parison of third-pipe reuse systems and seawater desalination in Western Australia, allowing for consideration of a systems view as well as the different scales of operation. These two criteria emerged as particularly important. On the sustainability criteria established for this project and within the scope of the preliminary analysis undertaken, third pipe systems perform well against desalination as a sustainable water source option.

Introduction Sustainability assessment, put simply, is a process that directs planning and decision-making towards sustainability. It is an emerging field internationally, in use in the UK through the Sustainability Appraisal of regional plans, and also in Australia, Canada and South Africa where the most prominent application of sustainability assessment has been at the project-level or in response to project proposals (Hacking and Guthrie 2008). This is a slightly edited version of the presentation at Ozwater' 10.

Applications of sustainability assessment vary between two broad and inter-related purposes: • To improve the sustainability outcomes of planning and decision-making (often used internally by project proponents and organisations to inform their own decision-making); and • To evaluate these sustainability outcomes against accepted sustainability benchmarks. Internationally the Water Services Industry is increasingly using processes of sustainability assessment to make decisions about water services provision. The International Water Association has published "Sustainable Water Services: A procedural guide" (Ashley et al. 2004) the outcome of the SWARD project (Sustainable Water industry Asset Resource Decisions). The Water Services Association of Australia has also published Sustainability Framework of Urban Wat er Systems, noting that the while trad itionally economic and engineering considerations have dominated the project option evaluation process, the community now demands that all options under consideration are assessed in a broader context, to ensure they deliver a sustainable outcome (WSAA 2008). The WSAA Sustainability Framework is intended to assist the urban water industry to achieve sustainable use of scarce water resources, by developing a methodology for evaluating the sustainability of the various supply and demand options taking into account economic, environmental, human health, technical and social considerations. Water Service Providers in Australia are increasingly using sustai nability at both an overall operational level, as well as using sustainability assessment as a decision-making tool. For example, South East Water in Melbourne prioritise

sustainability in a set of principles that help guide their decision-making principles, combined with a Sustainability Framework, Sustainability Multi-Criteria Analysis Tool, and a Stakeholder Engagement Tool. In Melbourne, Yarra Val ley Water applied a Sustainability Assessment Framework to evaluate water source options for a new development. The process considered eight options against 19 criteria (CSIRO 2005, Pamminger 2009). The Water Corporation (2008) in Western Australia also used a Sustainability Assessment process to evaluate a large number of water options being considered in their 50-year plan Water Forever. This paper reports on a project that undertook a preliminary comparison of third-pipe reuse syst ems and seawater desalination in Western Austral ia. 'Third pipe' or dual reticu lation systems treat wastewater, stormwater or groundwater which is then retu rned to the customer for non-drinking water uses such as toilet flushing and landscape watering . Around Australia there are a number of successful third pipe systems already implemented. In a review of these systems, there was typically a 40% reduction in scheme water use and greener suburbs than those surrounding. Some land developers found these initiatives led to improved lot sales compared to adjacent subdivisions without third pipe (Anda & Beyer 2009). Third pipe systems have been less common in Western Australia, however a number of urban land developers, including Landcorp, Armadale Redevelopment Authority and Midland Redevelopment Authority have been planning for third pipe systems in their new residential developments.

I hm.J p1µe SY..>h,111S

perform well against desalination. water SEPTEMBER 2010 67


sustainability design for urban water In Western Australia t hus far the main supply response to a decline in available water resources has been to construct desalination plants to input water into the Integrated Water Supply Scheme. The Perth Seawater Desalinat ion Plant was constructed at Kwinana in 2006. The Southern Seawater Desalination Plant is currently being constructed at Binningup. Although desalination is currently the preferred solution to water supply problems in Western Austral ia, it was considered important to compare t his to t hird pipe systems on the basis of sustainability criteria, in order to evaluate whether third pipe could be considered a sustainable and viable option in providing alternative water resources in the future. This paper concentrates on t he importance of a sustainabi lity assessment and decision-making process t hat allows for consideration of a systems view of the urban water system, as well as taking account of t he different scale at which various water source options are operating. These two issues emerged as particularly important in the comparison of third pipe and desalination schemes in Western Australia.

Sustainability Framework The four sustainability assessment frameworks mentioned above were examined and compared for the purposes of developi ng a Sustainability Framew ork that aims to adopt t he best practices of each. The final sustainability criteria are listed in Table 1. Given the scope of the project, only a preliminary and coarse assessment based on readi ly available information was undertaken. This paper wi ll not describe in detail the outcomes of this prelim inary assessment of the two options - desalination and third pipe but wi ll rather focus specifically on two of the technical criteria from Table 1: "Systems analysis" and "Scale'.

Systems analysis An open system is a system that continuously interacts with its environment. The interaction can take t he form of information, energy, or material transfers into or out of t he system boundary and makes use of processes within the system boundary to enable throughputs. In t his situation we are concerned with water, wastewater, their contaminants and the associated energy and emissions.

68 SEPTEMBER 2010 water

Table 1. Sustainability Criteria. Economic

Life cycle costs Social cost Social benefit and willingness to pay Technical

Systems analysis and resilience Flexibility and scale Fit-for-purpose Reliability Social Health Risk Community acceptability Community understanding and involvement Environmental Water resource efficiency Material efficiency Energy and Greenhouse intensity Land-use and disturbance Nutrient impact Governance

Responsibility and accountability Regulation and institutional capacity

refereed paper

ranges. Similar to systems analysis, t his criterion does not currently exist in any of the sustainability frameworks reviewed, yet became important in attempting to c ompare third pipe and desalination, because of the fundamental differences between the two options. Definitions of scale cover a wide spectrum: • 'Centralised' systems are sometimes considered to be those serving > 10,000 houses or 100,000 people. • 'Decentralised' systems on the other hand are considered to be community, cluster, or neighbourhood scale water systems typically serving up to 300 homes, but also encompassing developments up to 2000 homes (by the AWA Integrated & Decentralised Water Systems Special Interest Group). • 'Small' water systems are considered to be < 100,000 Ud or - 100 houses (by the IWA Specialist Group for Small Water and Wastewater Systems) • Cluster scale = 4 to 100 houses

Systems theory is an interdisciplinary theory about complex systems in nature, society, and science. More specifically, it is a framework by wh ich one can investigate and/or describe any group of objects that work in concert to produce some result. As an extension of this theory, systems analysis is the interdisciplinary part of scienc e, dealing with analysis of sets of interacting entities, the systems, and the interactions within t hose systems. It is also an explicit formal inquiry carried out to help someone, referred to as the decision maker, identify a better course of action and make a better decision than might have otherwise been made. A systems analysis is required to compare the sustainability of different sources, recycling and disposal options under consideration. For example, seawater desalination and third pipe have different inputs and outputs at different parts of the total urban water cycle. Their system boundaries can also be located differently in time and space. This criterion does not currently exist in any of t he sustainability frameworks reviewed, yet became important in attempting to compare third pipe and desalination.

Scale The issue of scale needs to be examined for certain options because t hey may be operating in different quantity/ quality

• Household scale is also referred to as lot scale or unit scale. Consideration of scale in the analysis of the two options of desalination and third-pipe is required to account for t he very different scale at wh ich these options operate. The scale at which systems are designed also has implications for the flexibility within that system. For example, smaller scale systems ac ross a city will be more flexible to meet local variable needs.

Mapping Issues Against the Framework A preliminary assessment of the two options - t hird pipe and desalination was undertaken on the basis of the extent to which the options fu lfilled the identified sustainability criteria. Specifically, the major issues relevant for each of the criteria were identified and a preliminary assessment of those issues based on readily-available sec ondary research. A summary of t his preliminary analysis is contained in Table 2. Clearly positive factors are shaded green and clearly negative factors are shaded red. A fu ll sustai nability assessment would be required to quantitatively or accurately rate each of these factors.

Systems analysis A systems analysis of the two options of desalination and third-pipe is required to

technical features


[7'l

sustainability design for urban water

refereed paper

account for the very different role that each of these options can play in the urban water system, wh ich,in the case of Perth, is the Integrated Water Supply Scheme (IWSS). A systems analysis also allows for the assessment of the overall resilience of the urban water system to be assessed. Desalination

The Water Corporation system is currently based on a single pipe in, single pipe out model - a centralised system. Seawater desalination is a potable water production process both within and as an input across t he IWSS system boundary supplyi ng the 'first' pipe. Third pipe

A third pipe scheme can be characterised as a system by itself with the inputs being either: sewer mining, a stand-alone WWTP or a groundwater source, and the output being non-potable water. Th ird pipe schemes can also be seen as a process component contributing to the throughput of the entire IWSS where these inputs/outputs are occurring within the system boundary.

In the first case above the third pipe scheme can be analysed with the system boundary around the subdivision it serves. In the case of a subdivision far inland from the coast, this localised system would compare with t he seawater desalinated water supply as an input from outside with a relatively high energy cost attached to it due to the pumping from the coast.

levelised cost in a convent ional analysis compared with seawater desalination. However, a systems analysis can point to other factors below not normally included. Third pipe systems: • free peak capacity in potable water supply; • free summer capacity in central wastewater system (and winter capacity t o a lesser extent, i.e. from toilet flushing);

A thi rd pipe scheme does not supply the first pipe, rather it is a localised process within t he system boundary, using the 'second' pipe (sewer mining) or groundwater or rainwater as its source to supply a new pipe internal to the system, the third pipe. Thus, it cannot be fairly compared directly to seawater desalination at the scale used by Water Corporation.

• can be an alternative source of nutrients for plant growth.

Comments

Desalination systems:

A conventional analysis of a seawater desalination plant would set the system boundary around t he total IWSS. With the seawater desalination plant running full t ime in this system t he levelised costs can ap pear favourable. The thi rd p ipe scheme may appear to have a higher

• require new sources to be integrated into distribution and wastewater t reatment systems;

• requ ire infrastructure development for local schemes on ly; • defer associated source and infrastructure development;

• can be integrated into the IWSS at strategic points along the coast as required or as land and environ mental constraints permits;

At last, the real facts on a range of pumps that 'tick ALL your boxes' Sometimes the 'old' ways of doing things just can not tick all the boxes any more. Like avoi ding hav ing to pull maintenance crews away from their evening meal to service yet another choke situation ... Or having to deploy extra manpower to haul the pump out of the sludge to service it ...when with the right pump, it

could be situated above ground and done in minutes by one person . A LOT has happened in design and tech nology that you need to know about.

llm -----1 ,

So we've prepared a series of White Papers to help you 'tick ALL your boxes' next time you specify pumps.

r!f Above ground pump

r:J/ Lower power costs serviced in minutes fl Improved odour control r!f Lower expenditures ~ Engineered & proven over fl Fewer blockages nearly eight decades ~ Smaller carbon footprint r!f Guaranteed service in r:J/ Reduced labour costs power outages And ·more ...

Get these FREE pump facts white papers by phone or online NOW www.pumpfacts.com.au

D

Self Cleanlng Wet Well - the 'Inside story' on a radical design approach

D

Auxlllary Pumping during power outages at higher flow rates to cope with storm conditions

D

Lowering Your Pump Station Carbon Footprint - How to reduce auxiliary machinery needs & maintenance hours

D

Self Priming Pumps for Your Sewage Pump Stations - 1O compelling benefits producing higher efficiency and operational staff savings

To make sure YOU are in the loop, request your selection of these new free White Papers online at www.pumpfacts.com.au or call NOW on 02 9647 2700. NO OBLIGATION. NO COST. Municipal & Industrial Wastewater Mining Industrial Process Pumping (gear pumps) Petroleum

water SEPTEMBER 2010 69


l-.J

sustainability design for urban water

refereed p a per

Table 2. Summary of third pipe and desalination issues relevant to each of the sustainability criteria. Third pipe

Desalination

Levelised cost Social cost

Slightly higher overall cost due to smaller scale Nothing significant

Social benefit and willingness to pay

Amenity of greener gardens Associated increased property value Attenuates rural cross-subsidisation

Cheaper with current technology Atmospheric pollution (not a social cost once internalised) Cost risk of marine impacts Water is incorporated into IWSS therefore willingness to pay is not relevant here

Factor Economic factors

Technical factors

Systems analysis and resilience

Flexibility and scale

Fit-for-purpose Reliability

Frees peak capacity in potable water supply Frees summer capacity in central wastewater system Associated deferred source and infrastructure development Economic at small scale Seasonally valuable supply Diversity of supply increases resilience Lower quality sources used for non-drinking purposes conserves drinking quality water in the IWSS Greater water utility because of double duty Increased water security for regional areas

An input to the system that can be easily integrated into the IWSS system High pumping costs and GHG emissions for consumers not close to the coast Economic at large scale Requires full-capacity operation to maximise scale benefits Blending into IWSS results in poor (unfit) match between high quality source and non-drinking uses Rainfall-independent water security for populated coastal regions Large proportional of overall water supply from one source

Social factors

Health Risk

Given no potable use, indirect transfers from inherent cyclic process provide potential infection pathway, except where a barrier treatment technology is used such as MBR

Substantial chemical use in RD membrane maintenance may represent minor health risks

Community acceptability

Wide range of acceptability for indirect uses and increasing acceptability over time as adoption widens Strong perception of high social amenity derived from experience in regional areas Limited understanding in Perth of third pipe schemes but are well established in eastern Australia Sense of ownership for community schemes and greater control over garden watering Requires community to refrain from 'adventurous' use

Indistinguishable product from scheme water therefore broad community acceptability Some localised objections to greenhouse emissions and marine salinity impacts No driver for greater community understanding

Water resource efficiency

Water does double duty

Material efficiency

Water in third pipe is locally derived so the material required for its employment is small Reduction in system infrastructure elsewhere in IWSS

Energy and greenhouse intensity Land-use and disturbance

Displaced potable water at lower specific energy required In hand with greenfield suburb developments, in basements for urban renewal projects

Nutrient impact

Reduced nutrients to ocean outfalls

Hard work being put into producing a new resource Minor deprivations of ocean resource Perception of greater efficiency Leverages existing infrastructure subject to distance from IWSS Wrong direction in greenhouse emissions Significant shoreline land allocation, where land is often of high environmental, social and economic value Nutrients as pollutants persist

Community understanding and involvement

Environmental factors

Governance factors

Responsibility and accountability

Regulation

Design standards for third pipe systems do not yet exist in WA Unclear responsibilities Weak direction in infrastructure innovation Lack of co-ordinated approach in regulatory framework to meet State recycling target

â&#x20AC;˘ have high pumping costs and greenhouse gas emissions for consumers not close t o the coast. From this very brief and preliminary syst ems analysis of the urban water syst em it is clear that there are a mult itude of issues that need furt her development and research in order to

70 SEPTEMBER 2010 water

Clear model for procurement, ownership, and operation

Clear model for regulation

undertake a more comprehensive sustainability assessment.

Scale Consideration of scale in the analysis of the two options of desalination and thirdpipe is required to account for the very different scale at which these options

operate. The scale at wh ich systems are designed also has implications for the flexibility wit hin that system. Third pipe

In general, t hird pi pe schemes are co nsidered to be small scale and decentralised. Theo retically, a third pipe

technical features


scheme can be built across all of Perth as a large scale central ised scheme, however, the costs of trenching through existing suburbs wou ld currently render this unviable. Installing a third pipe at the smaller scale of a new subd ivision or an urban renewal project where trenches are being opened for other services would be more viable. This scheme could be centralised at the scale of the village but decentralised relative to the IWSS. The flexibility of third pipe schemes can be expressed in terms of adaptability to the locally available water source. For example, in areas far from the coast where pumping desalinated seawater adds to the energy and expense, and where groundwat er is already over-allocated , but where local sewers are loaded or stormwater ASR can be established then conditions could be ideal for third pipe. Small scale systems, such as third pipe, may have the flexibility of being able to be turned off as required without having a major impact on operating or depreciation costs. However, membrane systems require minimum run times and biological systems require minimum feed levels in order to keep micro-organisms alive. In Western Australia, the Gracetown and Hopetoun small town urban renewal projects by Landcorp have demonstrated that local third pipe schemes are viable. In the Hopetoun situation this was demonstrated through thorough economic analysis that resulted in a very different outcome to the Water Corporation base case of a heavily engineered sing le pipe in and single pipe out system. With t he shutdown of Ravensthorpe BHP Nickel mine there were no further requirements to develop housing in Hopetoun, and therefore the project did not proceed to implementation. Gracetown will proceed to implementation albeit at a smaller scale than originally proposed due to the economic downtown. Desalination

A seawater desalination system connected to the IWSS is considered to be large scale. The IWSS is considered to be a central ised scheme in terms of regulat ion, management and technology. Once installed at a large scale there is limited flexibility as in order to achieve the lowest levelised costs the systems may need to be ru n full time. The current Kwinana and Southern (Binningup) seawater desalination plants by Water Corporation for the PerthMandurah IWSS are large scale facil ities at 45 GLpa and 50 GLpa respectively each contributing approx 15- 20% of the freshwater to the IWSS. At this scale the plants must operate close to full-ti me in order to provide cost -competitive water. However, they will be vul nerable to rising energy prices as the demand and costs increase for renewable energy sources combined with imminent carbon price implementation Smaller scale systems are currently in the test phase that could produce 0.2 GLpa freshwater fro m RO desalination and wave energy (for example, the CETO tech nology currently under development by Carnegie Corporation). Therefore, at this scale these systems are ideally suited for small coastal towns and small coastal vi llages along the metropolitan coast, and without the energy and greenhouse implications of the Kwinana and Binningup desalination plants.

Tyco Water suppli ed the entire 52km of 375 mm ductil e iron pipe w ork and associat ed fittings for the Hamilton-Grampians Pipe line. Tyco Water not o nly supplied but delivered pipework t hroug hout the desig nat ed pipeline alignment , requi ring close coo rdin ation between all parties - Tyco Wat er, Pad bury Amber, GHD and Wan no n Wat er. Tyco Water al so provi ded design adv ice and reco mmendat io ns t hro ughout t he entire construction perio d. For t he rig ht partner on your next pipeline p roj ect ca ll 1800TYCO H2O.

wawv

tqca

your pipeline partner


~

sustainability design for urban water Comments

Seawater desalination is appropriat e as a large scale solution on the coast, and has less flexibility in requi ring operation at full capacity to maximise the benefits of scale. Third pipe, on the other hand, can operate readily as a large or small scale solution anywhere in the total system.

Evaluation and Conclusions Table 2 provides a summary of the preliminary analysis of how each of the options performed against the sustainability criteria. On the basis of this preliminary comparison, there is clearly a case for the further consideration of third pipe systems as sustainable water source options withi n the IWSS in the future. On the sustainability criteria established for this project and within the scope of the preliminary analysis undertaken, third pipe systems perform well against desalination as a sustainable water source option.

In the process of identifying a sustai nability framework that wou ld enable the options of desalination and third pipe to be fairly and comprehensively assessed for their contribution to sustainability, a number of gaps in the existing water service industry frameworks were identified. In particular it is recommended that further work be conducted on undertaking a systems and resi lience analysis of water source options that allow options such as third pipe and desalination to be assessed for the extent of their fit into a system strategic framework.

refereed paper

consulting firm ENV Australia Pty Ltd. Email M.anda@murdoch .edu.au . Dr Nicole Hodgson is a lecturer in the School of Sustainability at Murdoch University. Dr Stewart Dallas has a PhD in the field of Ecological Engineering and is also a qualified civil engineer. He is currently Project Manager for the Wungong Urban Water Project which aims to construct the first large-scale recycled water scheme for residential development in WA.

References Ashley, R., Blackwood, 0., Butler, D. and Jowitt, P. (2004). Sustainable Water Setvices: A procedural guide. International Water Association Publishing

The Authors

Pamminger, F. (2009) "Water Industry Example of Applying a Sustainability Assessment Framework". Presentation at Creating Water Sensitive Cities in Australia. Perth 9-10 February 2009.

Dr Martin Anda is Academic Chair and Senior Lecturer in Envi ronmental Engineering at Murdoch University. He is also Pri ncipal Engineer Sustainability at

Water Corporation (2008a) Water Forever: Sustainability Assessment. December 2008. Water Services Association of Austral ia (2008). Sustainability Framework. WSAA Occasional Paper No. 27. February 2008.

Aeration You Can Rely On. If you want efficient aeration, along with quality advice and support, ESA/VI is the aerator for your business. Benefits of ESA/VI aeration: • Energy efficient aeration • Delamination of temperature layers • Lower evaporation rate • Smooth & quiet operation • 3 Year warranty ... and service to you is our priority.

e esam www.sidechannetbtowers.com. au Phone 03 9484 5719

72 SEPTEMBER 2010 water

technical features


.'

refereed paper

sustainability design for urban water

MULTI-CRITERIA SUSTAINABLITY ANALYSIS FOR THE MARGARET RIVER PROJECT D Visser, K Edwards, M Hunt Abstract

For something to be defined as sustainable it must improve human well being without compromising t he local or global situation over t he long term . Choices are no longer a matter of cost alone. Rather, a conscientious move has been made to give due consideration to the fu ll t riple bottom line (Figure 1).

The Water Corporation and GHD have joined forces to urgently develop t he design for new Margaret River water source works. The Water Corporation was concerned with the security of supply for t he existing water source, which is contaminated and in response, initiated this project which included,a new bore and ON 450 pipeline, a 15 MUd Water Treatment Plant, 15ML Clear Water tank and an upgrade of the Ten Mile Transfer Pump Station. Wh ilst developing the design, the team recognised its responsibility to contribute to t he goals of sustainable development, that is, about improving human well being without compromising the local or global environment over t he long term. The Water Corporation has recently developed a visual technique for multicrit eria analyses which has been em braced by GHD for various decisions on projects. The method, is generally known as the Sustainability Wheel Technique. This approach to the assessment for Margaret River is outlined in this paper. As part of the process community stakeholders were actively engaged from the start of t he project. Forums were held to explain the proposal and for the commu nity t o express their views and concerns .

Introduction The Margaret River water supply scheme, which delivers water to Margaret River and neighbouring towns, is currently supplied by the Ten Mile Brook Reservoir and is supplemented with water from the Margaret River. Due to a lack of rainfall and increasing demand, the Water Corporation brought forward its plan to implement a Yarragadee new groundwater source. This new source also negates the need to use the Margaret River, which under revised regulations, has become undesirable fo r drinking water supply. The river water quality is poor

Figure 1. Triple Bottom Line. (spec ifically high turbidity and Cryptosporidium and Giardia contamination) and req uires extensive treatment which is not in keepi ng with sustainability principles. Three separate packages of work made up the Margaret River source works project: 1. 10 MUd bore + 20km raw water pipeline; 2. 15 MUd water treatment plant (WTP); and

For this reason, stakeholder engagement, especially the Margaret River community, was a priority for the team . Forums were held in Margaret River and Rosa Brook on two separate occasions to disc uss the proposed works and to answer any questions. A similar philosophy applied to the selection of the core treatment process for t he WTP. Historically the decision about t reatment processes has been largely driven by capital and operating costs. However, the team acknowledged that a net present val ue analysis alone was inadequate. Environmental impacts, operational impacts and other criteria were also considered to achieve a sustainable design , and in view of the urgency, it was noted that testing of alternative processes by pilot plants was not feasible.

3. 15 ML Clearwater tank + 8km clearwater pi peline.

The approach to th is assessment for Margaret River is outlined in this paper.

The tank project also included t he upgrade of the exist ing transfer pump station at Ten Mile Brook Reservoir and an associated raw water pipeline to transfer reservoir water to the new WTP. In late 2008, the Water Corporation awarded the design to GHD.

Project Requirements

The Water Corporation's aim for all of its projects is to provide safe drinking water now and into the future and to do so in a sustainable way. GHD recognises its corporate responsi bility to contribute to the goals of sustainable development.

The lowest cost design is not the optimal solution.

New source: 10 Ml/d bore and raw water pipeline The new Yarragadee bore wi ll have capacity to supply 10MUd of groundwater to the WTP via approximately 20km of pipeline, mainly within t he verge of the road with a minimum in private property With the objective that residents wou ld not be adversely affected, t he project team liaised with land owners on a one-to-one basis to discuss and negotiate t he works.

Water treatment plant (WTP) The Water Corporation purchased a parcel of grazing land approximately 2 km from t he Ten Mile Brook Reservoir. The land will be used for the WTP and

water SEPTEMBER 2010

73


sustainability design for urban water

•,]

r e f e r ee d p a per

new 15 ML storage tank. Water will be pumped to the WTP from each of the two sources (Ten Mile Brook and Yarragadee) and gravitate from t he 15 ML tank into the Margaret River townsh ip following treatment. The water t reatment p lant was designed to t reat 15 MUd received from the two sources and is expandable to accommodate an additional 10 MU d from another bore source giving a total ultimate treatment capacity of 25 MUd. The Water Corporation com pletes reg ular water quality analysis of its water supplies, so comprehensive data was available for the Ten Mile Brook source. However, as the bore had not been drilled yet, very little water quality data were available for that source. Additionally, data available from monitoring bores in t he area were not considered representative of t he aquifer. Few data were available and many of t hese had unexpected values. Th is meant t hat the various WTP basis-of-design assumptions had to be made based on judgement, rather t han measured variables, adding complexity to t he design process. This was a col laborative process between GHD and Water Corporation. Upon comparing the Ten Mile Brook water quality data and the collective knowledge on the Yarragad ee source, t he design team noted that the quality issues associated with the two sources had similarities (although the magnitudes were different). In particular, it was noted t hat: • A pat hogen risk was present - albeit relatively low;

Layout of the Proposed Water Treatment Plant. • Due to the proposed dept h for the bore, it is expected that the wat er wi ll be warm. Based on t he observed water quality issues, the requirements for water treatment were discussed and prioritised. The agreed primary treatment object ives were: pathogen t reatment; t urbidity, iron, manganese and colour removal; trihalomethane formation pot ential (THMFP) reduction; and temperature management. Secondary objectives were also identified (such as water stabilisation, pH control and solid waste handling) but are not discussed further in this paper.

• Both waters exhibited an elevated t urbidity; • Bot h waters exhibited elevated iron and manganese levels;

• The organic content of t he wat er was elevated posing a possible disinfection byprod uct (DBP) risk; • The composition of the water (particu larly t he reservoir) was poorly stabilised such that it has potential to be corrosive;

7 4 SEPTEMBER 2010 water

In applying th is technique the following key steps were undertaken: • STE P 1: All options were identified and short listed based on key merits. The short list of options was used for more detailed analysis using t he Sustainability Wheel method. • STEP 2: General categories of selection criteria were identified t o best suit the options to be assessed. Exam ples include: Financial, Social, Environmental , Engineering and Operations & Maintenance considerations. The categories were distinguished on the chart by means of different colours. The categories were divided into criteria. For inst ance: clearing requirements and energy use for the environmental category. These criteria were represented on the chart by means of angular segments.

• The colou r of the waters was above t he Water Corporation's guideline;

• Data for the reservoir indicated that the water has elevated aluminium; and

Sustainability analysis The move towards sustainable decision making has led to the use of multi-criteria analytical methods. A range of multicriteria analytical methods have been used. The Water Corporation recently developed a visual techniq ue for multic riteria analyses wh ich has been embraced by GHD for various decisions on projects. The method, wh ich utilises a circular target chart as illustrated in Figure 2, is generally known as the Sustainability Wheel Techn ique.

Figure 2. Example Sustainability Wheel.

• STEP 3: A matrix of guidelines was prepared to aid ranking of

technical features


''

r e fere e d paper

each option based on the criteria. For each criterion defining guidelines were written and agreed by stakeholders to distinguish between rankings. • STEP 4: Using t he guidelines, stakeholders agreed on the rankings to be applied for each of the options. These rankings were represented by concentric rings of increasing radi i. (Fill to 1 ring = undesirable, 2 rings = negotiable, 3 ri ngs = acceptable and 4 rings = preferred) • STEP 5: Stakeholders discussed the information displayed on the Sustainability Wheel charts and agreed on the way forward. The use of colour allowed the strengt hs of an option to be seen at a glance. The stakeholders had opportunity to have an informed discussion about the priorities for the various criteria without being immediately led toward s an implied solution by the result of a matrix calculation or otherwise. The following describes how this approach was applied for the Margaret River project.

STEP 1: Define Viable Options The Water Corporat ion has developed a Water Treatment Manual which provides advice on t he minimum level of treatment required (from a biological perspective) for sou rces of various levels of quality. The Margaret River sources were assessed as "Level II - Moderate Faecal Contamination". This rating was driven by the quality of the Ten Mile Brook reservoir. Accordi ng to t he manual, t he minimum level of treat ment required was coagu lation/ flocculation followed by filtration and chlorination. The Water

sustainability design for urban water Corporation has extensive experience with this treatment process.

7. Aeration/Blending --+ PAC --+ OAF--+ Media Filter --+ Gas Chlorination

The exist ing treatment at Ten Mile Brook is based on the use of gas chlorination. With th is in mind, alternative disinfection processes were not considered in detail.

8. Aeration/Blending --+ OAF --+ Media Filter --+ GAC --+ Gas Chlorinat ion

A combi nation of options was selected as the design for management of the expected high Yarragadee water temperatu re. These included aeration of the water supply, blending with t he cooler surface water and optimisation of the bore depth to balance water temperature and chemical composition. The water treatment process selection focussed on the turbidity, iron, manganese, colour and THMFP treatment measures. A range of opt ions were considered in detail for these treatment measures as summarised in Table 1. With t he completion of the short listing step the fol lowing nine (primary) treat ment train opt ions were carried forward for sust ainability analysis: 1. Aeration/ Blending --+ PAC --+ Actiflo® --+ Media Filter --+ Gas Chlorination 2. Aerat ion/Blending --+ Actiflo® --+ Media Filter --+ GAC --+ Gas Chlorination 3. Aerat ion/Blending --+ MIEX® --+ Actiflo® --+ Media Filter --+ Gas Chlorination 4. Aeration/ Blending --+ PAC --+ DAFF --+ Gas Chlorination 5. Aeration/Blending --+ DAFF--+ GAC --+ Gas Chlorination 6. Aeration/Blending --+ MI EX® --+ DAFF --+ Gas Ch lorination

9. Aeration/Blending --+ MIEX® --+ OAF --+ Media Filter --+ Gas Chlorination

STEP 2: Define Categories and Criteria Discussions were held to determine the key assessment criteria for the water treatment process. The categories and criteria selected and applied to t he project are shown in Table 2.

STEP 3: Define Ranking Guidelines Discussion was then held to agree on the guidelines to be used to assess each option. Table 3 provides t he agreed guidelines. Note t hat t hese guidelines were developed specifically for t his project with t he options to be analysed being the basis for t he guidelines chosen.

STEP 4: Prepare Sustainability Wheels Sustainability Wheels were prepared for each of t he nine process t rain options in the short-list. The prepared wheels are presented in Figure 3. The assessment undertaken to prepare these was based on the guidelines presented in Table 3. Note t hat scores were not determined for unit costs. The reason for this was t hat due to project constraints there was insufficient time to provide an accurate assessment of t he operating costs. It was decided that, as operating costs were not likely to vary greatly between t he options, a d ecisio n cou ld be made on the grounds of the remaining criteria. Unit

Table 1. Core Treatment Options Considered. Treatment Objective

Considered Treatment Options

Assessment

Turbidity, Iron, Manganese and Colour removal

Direct (Media) Filtration

DISCARDED - solids load too high (potentially high risk with limited bore data)

THMFP reduction

Conventional Clarification & Filtration

DISCARDED - potentially unstable with variable raw water quality

Combined Dissolved Air Flotation & Filtration (DAFF)

SHORT-LISTED

Dissolved Air Flotation (DAF) Clarification and Filtration

SHORT-LISTED

Microfiltration/Ultrafiltration (MF/UF)

DISCARDED - potentially high risk due to limited time for piloting of iron laden waters

Actiflo® Process

SHORT-LISTED

Chloramination

DISCARDED - concerns relating to taste/odour and community acceptance

Enhanced Coagulation & Filtration

DISCARDED - Only expected to be suitable to enhance another process option

Powder Activated Carbon (PAC)

SHORT-LISTED

Granulated Activated Carbon (GAC)

SHORT-LISTED

Ozone/Biological Activated Carbon (BAC)

DISCARDED - Limited time for piloting; High risk due of bromate formation;

Nanofiltration (NF)

DISCARDED - too complex, high energy

Magnetic Ion Exchange (MIEX®)

SHORT-LISTED

water

SEPTEMBER 2010 75


sustainability design for urban water cost was however left on the list (although not assessed) in order to duly acknowledge it as an important consideration.

STEP 5: Discuss and Select Preferences The approach taken to select the preferred process design was to systematically eliminate, with open discussion, those options which demonstrated weakness in key areas of importance. This discussion was held at a meeting with key Water Corporation and GHD stakeholders.

[]

refereed paper

Table 2. Sustainability Assessment Criteria. Category

Criteria

------

1. Timing (approvals, lead times) 2. Engineering (proven technology, flexibility, robustness, stage-ability) Social Consideration

3. Amenity (footprint, noise, other impacts) 4. Local sourcing (local availability of suitable trades)

Environment Considerations 5. Energy use 6. Water use

7. Chemical use (quantity and nature) 8. Wastes (volume and nature) Economic Impacts

9. Capital costs

1o. Unit cost (whole-of-life) Operations & Maintenance

11. Operability (complexity, flexibility, skill level, down time) 12. After sales service/support (parts, services and chemical availability)

Options 3, 6 and 9 were eliminated first. These all include Magnetic Ion Exchange (MIEX®). From Figure 3 it is noted that these options were weak in terms of Risk, Finance and Operation & Maintenance with t he majority of these being scored as less than acceptable. The weaknesses were largely due to the higher complexity of the process and the limited knowledge of the performance of MIEX® without piloting.

being offered by few suppliers, the Water Corporation would have had limited flexibility with respect to the choice of vendors. This was seen to be undesirable. It was also recognised that the process has seen limited application for treatment of potable water in Western Australia - in other words, it has not been proven for these waters.

Options 1 and 2 (Actiflo® options) were also eliminated. Due to this process

This decision narrowed the process train choice to variations of Dissolved Air

Flotation (OAF), Fi ltration and Activated Carbon. Extensive discussion was held with regard to the choice of combining the OAF and filter in one structure (Options 4 and 5) as opposed to building two separate structures (Options 7 and 8). The Water Corporation expressed a strong preference in favour of the separated design, due to the significant process flexibility. For this reason options 4 and 5 were not considered further.

Table 3. Assessment Guidelines. 4: Preferred

CRITERIA

1: Undesirable

2: Negotiable

3: Acceptable

>6 rrionths late Unproven

Later than expected

On time

Deliver early

2 fnglneenn

Unproven at this size or in long term

Proven & Current

Proven & New

Process is unstable

Generally unstable

Usually self regulating

Self regulating

Not robust

Not usually robust

Usually robust

Robust

Not stage-able

Difficult to Stage

Stage-able

Easily stage-able

No knowledge

Limited knowledge

Knowledge in house

Knowledge in house (GHD & Water Corp)

Structures are highly obtrusive

Structures altered to minimise impact

Structures contain no obtrusive elements

Aesthetic structures

Extreme measures to meet noise regulations

Significant measures to meet noise regulations

No measures required to meet noise regulations

4 Local sourcing

No technology or skills in Australia

Some technology or skills in Australia

Minimal measures to meet noise regulations Most equipment or skills in Australia

5 Energy

> (X +15%)

(X +10%) to (X +15%)

X to (X +10%)

X

6 Water

< 90% recovery

90-95% recovery

95-98% recovery

> 98% recovery

7 Chemicals

A lot of chemicals Not all hazardous

A few chemicals Some hazardous

A few chemicals All non hazardous

8 Wastes

A lot of chemicals Many hazardous A lot for specialist disposal site

A lot for landfill A little for special disposal site

Moderate volume of waste for landfill

Little for landfill Potential for some recycling of wastes

9 Capital

> (X + 20%)

(X +10%) to (X +20%)

X to (X +10%)

X

10 Unit Cost 11 Operability

> (X + 10%)

(X +5%) to (X +10%)

X to (X +5%)

X

Score = 0.0 to 1.0

Score = 1.5 to 2.0

Score = 2.5 to 3.5

Score= 4.0

Less Australian supply, more overseas

Multiple suppliers High flexibility

3 Amenity

Equipment or skills in Western Australia

Operability Score =Flexibility + Downtime + Complexity + Skill Level

Flexibility (Score: Flexible = 1, moderate = 0.5, inflexible = 0) Downtime (Score: Low = 1, moderate = 0.5, High = 0) Complexity (Score: Highly complex = 0, moderate = 0.5, low complexity = 1) Skill level (Score: Higher skill level = O, moderate = 0.5, low skill level = 1) 12 Service/ Support

Sole Supplier

76 SEPTEMBER 2010 water

Restricted suppliers worldwide

technical features


sustainability design for urban water

refereed paper

The difference between the remaining options was t he type of activated carbon used (PAC in Option 7 and GAC in Option 8). PAC was considered to be a good solution in the short term - being less costly to install. Also, the expectation was that activated carbon treatment may only be required on an intermittent basis, which is ideally suited to the use of PAC. Although more costly to build , GAC was considered to be the better design for the long term , if continuous treatment with activated carbon is required. The key downside of this option, however, is that pilot t rials are preferable. With t he project being urgent, insufficient time was available for pil ot t rials . The decision was made to adopt Option 7 in t he short term with t he intention to investigate and retrofit Option 8 in the longer term , if necessary. The install ation of PAC would be included initially followed by piloting of GAC. When water demand for Margaret River increases and sufficient knowledge has been gleaned from GAC piloting, a

1. Actiflo® + F + PAC

2. Actiflo® + F + GAC

3. Actiflo® + F + MIEX®

CATEGORIES

RISK 1. Timing 2. Engineering

ENVIRONMENT 3 . Energy 4. Water 5. Chemicals 6.Wastes

SOCIAL 7.Amenity 8. Loca l Sourcing

ECONOMICS 9. Capital Cost 10. Unit Cost

OPERATION & MAINTENANCE 11. Operability 1 2. Service I Support

NOTE: Generally more evenly distributed colour = :, better (balanced)

choice

Figure 3. Margaret River Sustainability Wheels.

Pipe Lining & Coating PTYLimited Quality ISO 9001 8 SAIGLOBAL

Cement Lining - Fabrication - Surface Treatment "Servicing Australia's Water Industry"

0

.

'

.

d\

' ' A

'

P·.I pe-1·I Fll. flg,

~

.~

n f'

.

~

'

,

:

'

. . .•


sustainability design for urban water decision will be made as to whether GAC is justified.

15 ML Storage Tank and Treated Water Pipeline Material selection Although costs were compared for steel and concrete tank options, this was not the on ly criterion . Concern was raised over bushfire risks. The tank wi ll be located in close proximity to a large forested National Park and it is likely that a fire will occur at some point during t he life of the asset. Note that due to the lay of the land and operational req uirements the tank cou ld not be relocated away from the risk. A study was commissioned to assess the impact a bush fire may have on the tank. This assessment utilised Australian Standard AS3959 wh ich provides an assessment tool to determine the likely Bushfire Attack Level (BAL) and a maximum heat flux that construction elements will be exposed to in the event of a bushfire. The analysis indicated t hat the tank would be exposed to BAL 29, classified as a high risk, which according to the standard means that "There is an increased risk of ember attack and burning debris ignit ed by windborne embers and a likelihood of exposu re to an increased level of radiant heat. The construction elements are expected to be exposed to a heat flux not greater t han 29kW/m2." The material selection analysis used this information with material properties for steel and concrete to estimate the temperature increase when exposed to that level of heat flux. It was assumed that: • The tan k is empty and that no heat sinks are included; • The site is unmanned and has no active fire suppression or passive fire protection; • There is uniform temperature rise t hroughout exposed section; • The tank roof has been excluded from t he analysis on the basis that it is not "facing the fi re" and also that if damaged, t he roof can be more easily replaced than the t ank wall; and • The exposed steel or concrete will absorb 50% of the impinging energy. The analysis concluded that the temperat ure rise for the steel tank would be of the order of 600°C, where as concrete would be much less at on ly 32°C. Steel will deform at around 450°C. From the analysis the steel wil l only need

78 SEPTEMBER 2010 water

to absorb a portion of the available energy per area before buckling will occur. Should significant structural deformation of tank occur the tank would need to be demolished and rebuilt. Replacement of the steel tank would take approximately one year. The internal coati ng of a steel tank is likely to become damaged somewhere between 100-150°C. If a major bushfire occurs, damage to the liner would be almost certain . The internal coating would pyrolyse and may release toxins into the contained water. Based on t he above assessment t he steel tank option without passive fire protection was rejected as it is likely to be extensively damaged in the event of a major bushfire. The critical issue for the concrete tank is the temperature at the rebar - if t he bars get to 300°C t hey retemper and lose yield strength. The rebar on the external face of the tank will have at least 50 mm concrete cover. Calculations indicated that the temperature increase for a 50 mm t hick section concrete would be 50°C on average and therefore damage is not anticipated. If the rebar temperature did exceed 300°C, deformation of the tank or spalling may occur. For spalling concrete repair would be required and can be undertaken on an operational tank. Based on t his analysis and assumptions, deformation of t he tank is considered highly unlikely.

~

refereed paper

The 15 ML tank design exemplifies another case where cost, although an extremely valuable criterion, does not drive project decisions. In this case, environmental and risk criteria drove the mat erial selection towards the more costly outcome in the short term b ut a lower risk outcome in t he long term . Sustainability is about improving human well being without compromising the local or global social , economic or environmental situat ion over the long term . The discussed aspects of the Margaret River source works project illust rate the great need to consider all aspects of project rather than unduly focussing on ly on the impact on the bank account. GHD and t he Water Corporation are excited about their contribution to a sustainable society. The approach illustrated in this paper is adapt able in that it can be readily applied for any other application including process selections, pipe route selections, construction site selections, tenderer selections, management decisions and much more. It is important that the world's resources are preserved for the future.

The Authors

Discussion & Conclusions The Margaret River Source Works project is a sound example of the way in which projects can be made more transparent for all those concerned . Further, it demonst rates how a successfu l partnership between industry players and cooperation with a range of stakeholders can achieve sustainable results. Route selection studies for the Yarragadee pipeline works illustrated the benefits of involving community stakeholders at an early stage of the works. This is particu larly t he case where the pipeline was required to pass through private property. Negotiation with land holders was paramount to ensuring an optimal outcome for both parties. The design of the Margaret River water t reatment plant is a prime example where t he lowest c ost design is not the optimal solution despite its feasibility from a tech nical point of view. Rather, the design chosen is highly flexible and robust for ease of operation and maintenance.

Daniel Visser (daniel.visser@ghd. com.au) is a senior process (chemical) engineer with GHD Perth's Water & Wastewater Process Service Group. He is responsible for the coordination, process selection and design of the Margaret River WTP. Katherine Edwards (katherine.edwards@watercorporation. com.au) is a chemical engineer with the Water Corporation Infrastructure Design Branch. Katherine is the Corporation's Design Manager for the Margaret River suite of projects (WTP, tank, bore, pipelines and pump station upgrade). Matthew Hunt (matthew.hunt @ ghd.com.au) is a principal civil engineer with GHD Bunbury's Water Section. Matthew is GHD's project manager for the Margaret River suite of projects. He also coord inated t he design for the tank, bore, pipelines and pump station upgrade.

technical features


refereed paper

environmental water management

CFD MODELLING OF DESALINATION PLANT BRINE DISCHARGE SYSTEMS G Seil, Q Zhang Abstract

Te rminal rise height

Computational Fluid Dynamics (CFO) modelling was performed using the commercially-available CFO software FLUENT 6.3.26. The CFO modelling was based on the solution of the Reynoldsaveraged Navier Stokes equations. Two key issues arose during the course of this development work: the first was that of calculating impact dilution (dilution at the point of impact of t he plume on the seabed) and the second was achieving a specified target dilution within a defined mixing zone radius from the outlet diffuser nozzles. These issues are the focus of this article and wi ll be examined in the context of single and multiple jet discharges. This article is written to stimulate discussion and further research into the computational and p hysical modelling and experimental validation of brine discharges.

Introduction A key issue in seawater reverse osmosis desalination plant design is ensuring that brine discharged from the plant is diluted to meet regulatory standards (typically 50:1 dilution or background salinity plus 1 ppt) to minimise potential environmental impacts on receiving waters. The brine, which is denser than seawater (negatively buoyant), is generally discharged from one or more nozzles on a seabed outlet structure in the form of jets, with vertical and horizontal components of velocity. The turbulence associated with the jet causes the brine to mix with t he surrounding seawater, reach a so-called "terminal rise height" and then fall to t he seabed t o an initial "impact point " where it spreads form ing a shallow depth dense plume with salinity just above ambient salinity. Under sti ll water conditions, the spreading plume continues to mix with the ambient water due to turbulence and density variations, but eventually the turbulence declines and a shallow layer of hypersaline seawater forms on t he seabed. This is shown graphically in

Turbulent m ixing of jet with ambient flu id

Jet impact with seabed Ctl'f.'\)OltÂťIOICI

Spreading plume

Collapsing turbulence

-"'

"'""'' ...

...

- ,.

-. ,p'

- u '\,,~

(a) Time-Averaged

- 20

... (b) Instantaneous

Figure 1. Plume dynamics illustrated using three-dimensional laser-induced fluorescent measurements taken from Nemlioglu and Roberts (2006). Annotation by authors.

Figure 1 for a single jet discharged at an angle of 60° to the horizontal. The plume also moves due to sea currents and gravity down seabed slope. This is a benefit if there are no highsalinity sensitive habitats (reefs) in the path of the plume. There is also a benefit in passi ng over a sudden drop-off in seabed (as in Cockburn sound at t he southern end of the Callista Channel) in that the energy associated with the plume passing over the underwater "weir" can disperse the plume sufficiently to make it undetectable. Sea currents and unsteadiness due to wave orbital motion also enhance the dilution/dispersion of the plume. Sea currents also change the shape of the plume and the direction of brine transport. If multiple jets are discharged from nozzles of a multi-nozzle outlet diffuser structure t hen these jets may merge on the seabed, or they may merge even as they descend toward the seabed or are acted upon by cu rrents and waveinduced motion. The plume is then advected away from the diffuser structure by a combination of the prevailing sea currents and gravity

Physical and numerical modelling of brine plume dispersion.

J

currents. This is a complex hydrodynamic behaviour and one that is challenging to model using computational modelling methods. Diffuser arrangements are common ly inclined nozzles distributed along trenched or surface-laid outlet header pipes at seabed level or clusters ("rosettes") of nozzles in sets of four or more at seabed level. Nozzles are spaced or oriented to minimise overlap of jets, in water depths sufficient to prevent jets breaching the sea surface under all operational conditions. SKM developed the capability to model complex diffuser designs and layouts using Computational Fluid Dynamics (CFO). CFO modelling was performed using t he commercially-available CFO software FLUENT 6.3.26. The CFO modelling was based on t he solution of the Reynolds-averaged Navier Stokes eq uations. Two key issues arose during the course of this development work: the first was t hat of calculating impact dilution (dilution at the point of impact of t he plume on t he seabed) and the second was achieving a specified target dilution within a defined mixing zone radius from the outlet diffuser nozzles. These issues are t he focus of t his article and wi ll be examined in the context of si ngle and multiple jet discharges. Th is article is

water SEPTEMBER 2010 79


0

environmental water management written to st imulate discussion and f urther research into t he computational and physical modelling and experimental validation of brine discharges.

8

Single Plume Impact Dilution CFD model ling began by considering the discharge of brine from a single jet inclined at 60° to t he horizontal under a range of currents speeds and direction. The CFO modelling was validated against the data of Roberts et al. (1997) shown in Figure 2 for brine discharge from a single jet inclined at 60° to the horizontal under zero current conditions. In t he fig ure t he ratio of dilution (S) on the seabed to Oensimet ric Froude number (F) has been plotted against t he ratio of the horizontal distance from t he release point (x) to the product of the nozzle diameter (d) and Oensimetric Froude number. The dilution was measured at t he bottom boundary in the experiment along a line through t he centreline of t he plume. Oensimetric Froude number is defined as,

5

S/F 4

Pa

i

I

V

.

-

'f

'I'

0 0

x/dF

10

15

Figure 2. Comparison of predicted and measured dilution for a single nozzle discharge at 60° to the horizontal into stationary water using the SST k-w turbulence model with calibrated constants. Data from Roberts et. al (1997). decay of t urbulence and the formation of a non-turbulent hypersaline bottom layer. There is considerable scatter in the data due to the different values of densimetric Froude number used in the tests.

(1)

CFO calculations using the Renormalization Group (RNG) k-e turb ulence model of Yakhot and Orszag (1986) and Yakhot et al. (1992) and the Shear Stress Transport (SST) k-w tu rbulence models of Menter (1994) were initially validated against the experimental measurement data from Roberts et al. (1997), shown in Figure 2. The SST k-w turbulence model was subseq uently calibrated against this data leading to a modified SST k-w model.

5

4

- - - - ... 0

x/dF

Figure 2 compares the resu lts of the calibrated SST k-w turbulence model with the experimental measurements in Roberts et al. (1997) . The legend in the figure refers to a set of experiment numbers where near boundary concentrat ion measurements were made using a micro-conductivity probe. These experimental conditions cover a range of Oensimetric Froude numbers from 19.2 to 35.7. The RN G k-e turbulence model led to impact dilutions approximat ely half that of the experimental data. With further literature search the results of this calibrated turbulence model were compared with experimental measurements from Nemlioglu and Roberts (2 006) shown in Figure 3. It is interesting to note the difference in the experimental measurements shown in Figure 2 and Figure 3. Nemlioglu and Roberts (2006) believe there results to be more reliable th an those of Roberts et al. (1997) due to improved measurement techniques.

6

10

15

Figure 3. Comparison of predicted and measured dilution for a single nozzle discharge at 60° to the horizontal into stationary water using the SST k-w turbulence model with calibrated constants. The red and blue lines correspond to the results from two experiments performed at the same Densimetric Froude number. Data from Nemlioglu and Roberts (2006).

80 SEPTEMBER 2010 water

0J1oa DJ10b

i -- --- ---• • •• -... • ..... --- -- .. • ,. - ...--•--, ,. ,, ,, .. ------ . v,. •

I - - CFO I

0

.... -

'('

where Ui is the jet velocity, p is the density of the discharged fluid, Pa is the density of the receiving fluid and g is t he gravitational constant. It can be seen from the figure that the dilution: Froude No. ratio (S/F) is minimised as the plume impacts the seabed. It subsequently increases wit h distance from the impact point and t he plume mixes with t he surrounding water due to turbulence and density variations. Eventually dilution reduces and remains constant due to the

S/F

n111

DJ9 DJ11

,. "

End of mixing zone

Impact point

'y

1

J

DJ7

.

...

u. (p-pa) gd

••...

I -- CFO I

7

6

F=

...

refereed paper

In both cases, t he CFO results can be seen t o under-predict the impact and post-impact dilution. Further downstream the CFO results do not account for the decay of the turbulence. However, overall agreement is reasonably good in t he range of 1sx/dFs4, considering the complexity of the flow. CFO can therefore be used to provide a conservative prediction of dilution in the range 0sx/dFs 7. Figure 4 which corresponds to a surface of co nstant concentration,

technical features


environmental water management

~

refereed paper

must be achieved within a certain radius from the diffuser. To quot e an impact dilution, based upon these codes, w ithout acc ounting for the localised build-up of salinity over time near t he impact location, Interaction Between Multiple is misleading as the localised bui ldPlumes up of salinity will reduce both the impact and post -impact dilutions. After the single plume was studied CFD modelling on the other hand CFD modelling was extended to the Z X accounts for the impact of the study of diffuser arrays, multi-nozzle pl ume with the seabed and the risers and multi-outlet structure Figure 4. Shape of plume from single nozzle, shown build-up of salinity with time until a configurations. These were modelled by surface of constant concentration, at zero current steady condition is reached with the for zero current conditions or for speed. ambient surrounding water. small current velocities such as Therefore one can use Lagrangian0.1 mis. shape of the plume and the dilution of based plume modelling and CFD as Figure 6 shows the calculated plume brine, these models cease integration complementary t ools for the design of from an array of 10 diffuser nozzles and when the plume reaches the seabed, the brine diffuse systems, drawing on the corresponds to a surface at the same sea surface or some prescribed merits of both methods to provide a dilution ratio as Figure 4. The difference maximum time. For plumes that reach more complete analysis of system in the shape of the resulting plume the seabed, the model does not account performance. relative to a plume from a single nozzle is for the build-up of salinity over time, It must also be noted that Lagrangianclearly evident. Figure 7 shows the Lebreton and Black (2008a). based pl ume modelling can be used as calculated pl ume from a multi-nozzle Tools such as Visjet are therefore input int o hydrodynamic models of the riser at the same dilution ratio as the useful for assessing different diffuser mid-field, see LeBreton and Black other cases. designs in order to optimise their (2008b). These mid-field hydrodynamic In both figures the plume can be seen effectiveness and model the "near-field " models cover the bathymetry of the to bulge in the region between the which is of the order of tens of metres ocean up to several square kilometres individual jets. The shape of the plumes from the discharge location. Regu latory around the discharge site and account is also very different from one another, bodies prescribe that a specified dilution due to the direction of basic plume movement and also the way in which ambient water is drawn into and mixed with the discharged brine. Impact dilutions from the individual jets were in both case found to be less than for the equivalent single plume. Configurations of multiple outlet structures, each with multiple discharge nozzles were also studied. These calcu lations, which wil l not be discussed here, showed even more int eresting results due to the interaction between the plumes from Figure 5. Brine concentration on centreplane of plume. Red contour shows concentration, each outlet structure. illustrates the generic shape of the plume predicted by CFD using the RNG k-E turbulence model. The concentration on the centreplane of the plume is shown in Figure 5.

Whilst the CFD results are likely to be conservative, based on the validation shown in Figure 2 and Figure 3, CFD provides val uable insight into the physics of multiple jet discharges and their interaction.

blue contour background concentration at zero current speed.

Design of Brine Diffusion System Initial design of wast ewater diffusion syst ems is often undertaken by specifically coded software packages such as Visjet, see LeBreton and Black (2008a). These codes are based on a Lagrangian modelling of the pl ume and can produc e results within a fraction of the time a CFD calculation would take. These models have been extensively applied to buoyant plumes, whereas the brine plumes discussed here are negatively buoyant. In calculating the

82 SEPTEMBER 2010 water

Lz Figure 6. Shape of plume from 10 nozzle diffuser array, shown by surface of constant concentration, at zero current speed.

technical features


refereed pa p er

environmental water management

for sea currents, wave action and density variations in the water column (due to salinity and temperature) on the brine dispersion and hence seabed concentrations.

Suggestions for Future Research With the growing use of desalination as a means of supplying water to coastal communities, more research needs to be undertaken into the accurate physical and numerical modelling of brine plume dispersion. The physical modelling of multi-riser configurations with multiple nozzles on each riser presents a challenge due to the size of experimental facilities required to perform such a study at reasonable scale ratios. In addition testi ng needs to be performed so that a steady flow and concentration regime is established in the test tank and this requires large volumes of water. CFO modelling needs to focus on improving the pred iction of jet mixing and turbu lence decline of the seabed brine layer. CFO calculations can be validated initially for a single jet, but it is also important to validate models against discharges from multi-nozzle config urations.

Conclusions CFO modelling can add value to t he engineering design of desalination plant brine diffusion systems, by virtue of the val uable physical insight gained into the physics of multiple jet discharges and their interaction. CFO provides a bridge between near-field modelling using Lagrangian plume models and mid-field modelling using specialist three-dimensional hydrodynamic oceanographic models, as it accounts for t he actual build up of salinity around the impact point at low or zero current.

Figure 7. Multi-nozzle riser (left) and corresponding plume (right), at zero current speed.

Victorian Desalination Project Environmental Effects Statement. Menter F. R. (1994). "Two-Equation Eddy-Viscosity Turbulence Models for Engineering Applications". A/AA Journal, vol. 32, no. 8, 1598-1605, August 1994. Nemlioglu, Sand Roberts, P. J. (2006), "Experiments on Dense Jets using ThreeDimensional Laser-Induced Fluorescence (3DLIF)", Proc. of MWWD 2006 - 4th International Conference on Marine Waste Water Disposal and Marine Environment IEMES 2006 - 2nd International Exhibition on Materials Equipment and Services for Coastal WWTP, Outfalls and Sealines, Antalya, Nov. 6-10, 2006. Roberts, P. J. W., Ferrier, A. and Daviero, G. (1997), " Mixing in Inclined Jets", Journal of Hydraulic Engineering, pp. 693-699, August 1997. Yakhot, V. and S. A. Orszag, 1986. " Renormalization Group Analysis of Turbulence: I Basic Theory" , Journal of Scientific Computing, Vol. 1, No. 1 , p . 1-51 . Yakhot, V., S. A. Orszag, S. Thangam, T. B. Gatski and C. G. Speziale, 1992. " Development of

Turbulence Models for Shear Flow s by a Double Expansion Technique", Physics of Fluids, Vol. 4, No. 7, p. 1,510-1 ,520.

The Authors

Dr Gregory J Seil is SKM's Practice Leader in Computational Fluid Dynamics. Email: GSeil@skm.com.au.

Dr Qihong Zhang is Senior Computational Fluid Dynamics Specialist with SKM .

Acknowledgments The authors would like to thank Mr Daryll Pain and Mr Doug Franklin for reviewing the article and providing feedback.

References LeBreton, L. and Black, K , (2008), "Near-Field Numerical Modelling of the Desalination Plant Outlet Plume" , ASR, Ragian, New Zealand. Presented as Appendix 29 of Victorian Desalination Project Environmental Effects Statement. LeBreton, L. and Black, K. (2008), "Near-Field Numerical Modelling of the Desalination Plant Outlet Plume" , ASR, Ragian, New Zealand. Presented as Appendix 30 of

If this regulation is adding to your site requirements, CALL US N OW or visit our website at www.wacco.com.au Alternatively email us, info@wacco.com.au M el bourne:

B r i sba n e:

Launceston:

Hobart:

t 0 3 9335 1972 f 0 363441221

t 0 7 3367 1502 f 07 3367 1503

t 03 6344 9 110 f 03 6344 1221

t 03 6 2 3 1 4549

t 03 6231 4540

W.A. CROMARTY & CO providing electrical, automation end business improvement solutions for t he Water Industry. â&#x20AC;˘ Fa c!llt.itu !>e<tlo" 126 of the Commonwulth W,Utr Act 2007 â&#x20AC;˘ Pt0Yidm9 wa1tr data within te n C;uegorlts from Wutr Utlllty ComJ)inies to 80M

water SEPTEM BER 2010 8 3


environmental water management

~

refereed paper

DISCHARGE OF WATER TO THE ENVIRONMENT FROM POTABLE WATER INFRASTRUCTURE M McAlpine, M Breitfuss Abstract Critical matters for the testing, commissioning and long-term operation of bulk water pipelines and related infrastructure are the obligations (both statutory and social) associated with planned and unplanned discharges of wat er into the environment. Planning for these discharges requires not only shortterm considerations for individual events, but longer term considerations for discharging water during the lifetime of the infrastructure. In 2008, the Queensland Bulk Water Transport Authority (LinkWater) undertook a review of the compliance issues associated with the discharge of water from its infrastructure into the environment. Two significant issues identified included potential liability under common law and the requ irement to secure land for the purposes of draining water from priority discharge locations. This paper sets out the issues wh ich were examined by LinkWater and describes some of the actions taken to satisfy the authority's legal obligations.

Introduction Recent urban water reform in South East Queensland (SEQ) resulted in a new regulatory framework for water supply and the establishment of four new State water entities in July 2008 (Queensland Water Commission 2007). These reforms also saw the transfer of responsibility for regionally significant water infrastructure from local governments to the State. Under the South East Queensland Water (Restructuring) Act 2007, the Queensland Bulk Water Transport Authority (trading as LinkWater) was formed to own and operate bulk water transport assets in SEQ. From 1 July 2008, the authority became responsible for the management, operation and maintenance of regionally significant bulk water infrastructure in SEQ, referred to as the Water Grid. LinkWater currently operates and maintains some 550 km of bulk water

84 SEPTEMBER 2010 water

Controlled release of water during commissioning of the Southern Regional Water Pipeline. pipelines and associated infrastructure, such as pumping stations and potable water reservoirs. These assets include the Southern Regional Water Pipeline, the eastern Pipeline lnterconnector, the Northern Pipeline lnterconnector (Stage 1) and the Toowoomba Pipeline. Li nkWater, through its special purpose vehicle company LinkWater Projects, continues to construct potable bulk water pipelines and associated infrastructure to enhance regional bulk water supply networks in SEQ. LinkWater is obliged to consider a number of matters associated with the testing, commissioning and long-term operation of bulk water pipelines and associated infrastructure. For any discharges of water into the environment, LinkWater must consider both the long and short-term impacts of events on the environment (including relevant social, statutory and other aspects) during the lifetime of the infrastructure.

Planning to satisfy legal and duty of care obligations.

While environmental compliance is an important legal obligation for most water authorities, techniques for mitigating the environmental impacts of water discharges are reasonably well understood and there are established practices among water infrastructure constructors and operators. There are a number of examples in the literature which describe how the impacts of these discharges might be managed (Tjandraatmadja, Gould & Burn 2005; Tikkanen et al. 2006; Queensland Environmental Protection Agency 2008). However, issues regarding the long-term planning for water discharge locations and the potential impacts on landowners are not specifically addressed. This poses a significant matter for consideration by water entities responsible for the treatment and transport of potable water sources in Australia. In 2008, LinkWater undertook a review of the compliance issues associated with the discharge of water from its bulk water infrastructure. Two significant issues identified included potential liability under common law and the

technical features


['-l

environmental water management

refereed paper

requirement for securing land for the purposes of draining water from priority discharge locations along the pipelines.

• Drain-down of pipeline sections and balance tanks for maintenance or repairs

LinkWater has obtained freehold title and easements over the land containing the SEQ Water Grid. These agreements allow the authority the necessary access to construct, operate and maintain its infrastructure as well as the right to restrict access to the land containing the infrastructure. However, LinkWater has been advised that the standard terms of infrastructure easements do not necessarily specify the right to discharge large volumes of water overland, or undertake the necessary works to control such a discharge as part of 'normal operations'. In addition, freehold title and easements obtained for the bulk water infrastruct ure do not extend the right to allow the water to flow beyond these boundaries into neighbouring properties.

• Regular valve maintenance

Some water discharges, due to their volume, velocity or unpredictable nature, have the potential to cause harm to people or property. As such, improper planning for these water discharges may result in the authority breaching their common law duty of care. This paper sets out these issues and describes some of the actions taken to satisfy LinkWater's legal obligations.

The timing, location, volume and duration can be controlled for most planned discharges. Unplanned discharges resulting from system failures or other emergencies include: • Automatic opening of a safety-relief valve to relieve pressu re in the system • Overflows from balance tanks in the case of multiple system failures • Pipe bu rsts or leaks resulting from a number of factors • Purging of the pipeline in the event of an emergency (e.g. an increase in coliform counts and/ or taste and odour complaints from the public)

Lowering a 'pig' into a launch pit of the Southern Regional Water Pipeline.

a number of planned or unplanned circumstances. Planned discharges resulting from water quality or infrastruct ure maintenance procedures include:

Water Discharge Activities and Characteristics

• Pressure testing of the pipeline prior to commissioning

The SEQ Water Grid transports treated potable water between major bulk water sources in the region. Water may be discharged from this infrastructure under

• Commissioning of the pipeline • Pigging of the pipeline for the purposes of cleaning

The timing , location, volume and duration for unplanned discharges are more difficult to predict/control. The water quality from planned and unplanned discharges from the SEQ Water Grid can be categorised as either potable or non-potable. Potable water discharges wi ll be t he result of overflows, dewatering, pressure relief, pipeline breaks or leaks, and valve maintenance during the operational life of t he infrastructure. Non-potable water discharges wi ll be t he result of hydrostatic testing, cleaning and predisinfection stages of commissioning for new water mains, or cleaning (pigging) of operational mains.

New 16-48 hour Colitag™ Fast and Versatile test for E.coli and Total Coliform for the Water Industry!

Colitag™ is a fast test for the detection of

./ Fast time to results

E. coli and Total Coliform in drinking water.

./ Wide testing window provides flexibility

In as little as 16 hours your organisation

./ Growth Inhibitor for Aeromonas & Pseudomonas

is alerted to issues resulting in bacterial

giving fewest false positives/negatives

contamination and can take quicker action to

./ MPN or presence/ absence format available

correct the problem: today nottomorrow.

./ Detects 1 CFU in 100mls of water sample

./ US EPA approved ./ Optional method for Fecal Coliform & E.coli Contact samantha.dengel@thermofisher.com for ,/ Brighter blue fluorescence eliminates a free sample & further information on Colitag

J

1300-735-292

questionable positive E. coli

I www.t hermofi sher.com.au

Thermo Fisher SCIENTIFIC


environmental water management The amount of water discharged during any of these act ivities can range from a few thousand litres for valve maintenance to several megalitres for pressure relief, overflow events and the drain-down of pipeline sect ions. The ultimate vol ume of water is generally dependent on t he maximum design f low of the system, the diameter and length of t he pipe section (for section drain-down), and the duration of the discharge activity. Flow rates of water discharged from t he pipelines will generally be according to the maximum design flow rates of the system or drain-down valves. Drain-down valves on cu rrent LinkWater pi pelines have maximum design flows in the order of 500Us. Where t he flow of wat er can be control led, maximum permissible velocities prescribed in Appendix E of the Stormwater Quality Control Guidelines for Local Government (DNR & DE 1998) will apply. These maximum permissible velocities are designed to reduce the risk of erosion; however, flow rates at some of the recommended velocities may sti ll be sufficient to cause harm to permanent structures or injury to people and animal s caught in the flow . Unplanned discharges from a safety-relief valve or a balance tank overflow p rovision may be much higher than 500Us depending on the maximum design flow rate of the system. As an example, the maximum pump flow rate on the Sout hern Regional Water Pipeline is approximately 2500Us with the design flow rate of safety-relief valves rangi ng from 430Us to 1050Us. However, as these discharges are dependent on multiple system failures occurri ng simu ltaneously, they are not likely to occur frequently, if at all. None the less, an average recurrence probabil ity of 1 in 5 years was calculated for balance tank overflows f rom the Southern Regional Water Pipeline.

Discharge locations and drainage works A 'discharge point' refers to t he point at which t he water leaves the bulk water infrastructure. These might include a drain-down valve, a safety-relief valve or an overflow provision. 'Discharge sites' refer to the properties contai ning the infrastructure from which the discharged water will flow. The 'flow path ' refers to the path taken by the discharged water between the discharge point and t he end point. An 'end point' can be a waterway, private dam, st ormwater or other council drainage facil ity. An end point may also be where t he flow is expected t o be suffi ciently dissipated through infiltration and evaporation so it is no longer likely to

86 SEPTEMBER 201 0 water

cause harm t o people or property. Due to the nature of urban catchments in the region, the end point for many water discharges from the Water Grid (if unobstructed) is likely to be stormwater infrastruct ure or a local waterway. In some discharge locations, t here may be the need to perform either permanent or temporary drainage works on t he land along the flow path in order to direct or control t he flow of discharged wat er as t he water disperses from t he discharge site. These works may be to: • protect privat e properties • protect sensitive areas or land uses • prevent erosion along the flow path • direct water flows towards the end point.

Common Law Implications for Discharging Water The common law implications for allowing discharged water to run over landowners' properties without appropriate agreem ents in place include actions against Li nkWater for: • trespass • nuisance • negligence. Trespass wi ll occur the moment t he discharged water enters on the property of a landowner in circumstances where there is no prior agreement between LinkWater and the landowner. No harm to the landowner's property is required to support an action in trespass. In the absence of any harm to the landowner's property, the landowner will still have t he right to restrain LinkWater from allowing the discharged water from entering their land. Nuisance will occur where the landowner's use and enjoyment of the land is affected by the discharged water. As with trespass, an action in nuisance does not require actual damage to occur. However, an infrequent event which does not cause substantial interference is less likely to be considered a nuisance. It is a question of degree and of how substantial ly the landowner's use and enjoyment of t he land has been affected. Negligence occurs where a person owes another a duty of care and breaches that duty causing harm. The harm must be connected to t he action of the person who owed the duty. The potential for a claim in negligence wi ll always exist where there is a potential to cause damage to the property of t hird parties. The potential for a claim in

~

ref ereed paper

negligence against LinkWat er is highest where the velocity of the discharged water will be great enough to cause harm to people or property and/or where the discharge can not be controlled. In some discharge locations the pot ential for negligence towards an individual property owner may arise not from t he overland discharge itself, but from works tl:lat are undertaken to satisfy LinkWater's general environmental duty under section 319 of the Environmental Protection Act 1994 (OLD). For example, a permanent channel constructed to divert the f low of water away from an environmentally sensitive area may increase t he velocity of the flow to a level where it poses a greater risk of damage to people or property. If suitably drafted agreements are entered into between LinkWater and the affected landowners at the outset, then most eventualities may be covered in advance of t he discharge event. Even when an agreement has been entered into, Lin kWater can still be liable for actions that exceed the authority granted under the agreement or for any other thi ng which was not contemplated by the agreement. Therefore, such agreements must be drafted as broadly as possible.

Access Agreements and Land Tenure for Water Discharge The best way to prevent the majority of t he impacts of water discharge on landowners wil l be t hrough the appropriate location of discharge poi nts. Most bulk water pipeline projects are designed so that major discharge points are located away from residential areas or other infrastruct ure assets. However, due to the long operational life of b ulk water infrastructure (more than 50 years) and the projected population growt h in SEQ, it is likely that currently undeveloped areas may become built up over time, potentially impeding the f low of water and affecting the long-term viabil ity of these discharge points. Where LinkWater holds freehold tenure on the discharge site there is no obstruction to the control led discharge of water from their infrastruct ure other t han the general environmental duty of care which is common to all such activities. However, where the tenure held by LinkWater is a lesser form of tenure than freehold , t he terms of the easement, lease or licence (etc.) must include provisions which ensu re that LinkWater has appropriat e rights to allow water to be discharged over t he land containing the SEQ Water Grid infrastructure.

technical features


In order to allow the discharged water to flow overland across properties beyond the boundaries of LinkWater's infrastructure easements, an agreement will need to be reached with the individual landowners regarding rights of access including: • to permit the operator to run the discharged water overland • for personnel to access the discharge site • to limit the landowner's ability to inhibit the flow of discharged water • to preserve the long-term viability of the drainage path. While short-term agreements with individual landowners will be sufficient for many discharge activities, it was determined that a more permanent form of tenure over land affected by the flow of discharged water wi ll be required where: • the land owner's reasonable use and enjoyment of the land will be affected by the discharged water (under common law) • permanent works will be required to direct the discharged water or protect private property • ongoing access to the land will be required to maintain drainage works or monitor the discharged water • any other person's legal right to access the relevant land is affected. Acquiring land for the purposes of drainage is a costly and time consuming exercise; therefore, it is essential that priority drainage paths are identified which are either critical to the effective operation of the infrastructure or may have implications at common law if left unsecured. LinkWater also acknowledges that such acquisitions may set precedents for other water infrastructure owners and operators regarding the management of overland water discharge.

Prioritising Land Requirements for Water Discharge For some discharges, the potential for harm to people, property or the envir onment affected by the flow of discharged water is sufficient to require that a permanent form of tenure be taken over the land between the discharge point and the end point of the discharged water. In addition, some drain-down points are essential to the effective operation and maintenance of the bulk water pipelines and will require

protection of the flow path to maintain the viability of the discharge point during the operational life of the asset. These sites include safety-relief valves, balance tank overflows, critical drain-down valves for each hydraulic section of the pipe and pigging station drain-down points.

4 Competitors 1 Winner

Safety-relief valves and balance tank overflows Water discharges from safety-relief valves and balance tank overflows along the SEQ Water Grid can be at velocities great enough to harm people or property. These discharges are dependent on multiple system failures occurring; therefore, it is impossible to predict when such events might occur. While such discharges will occur from a fixed location and are infrequent, their unpredictable nature increases the risk of harm to people or property. For the effective operation of the system, it is also essential that water is able to drain away from the pipeline to prevent flooding should a discharge event occur.

Critical drain-down valves Drain-down valves are installed at low points along the pipeline. The function of the drain-down valves is for emptying or depressurising sections of pipe during maintenance procedures and emergencies. The location of drain-down valves is determined by the elevation of the pipeline and the speed at wh ich a section may need to be drained down. While there may be dozens of draindown valves on each pipeline section, it is possible to identify preferred draindown locations for planned discharge activities based on access, pipeline hydraulics and environmental impacts.

Pigging station drain-down Other drainage paths critical to the effective maintenance of the SEQ Water Grid are at pigging station drain-downs. Pigging stations are where the 'pig' (foam insert) can be launched and retrieved along the pipeline. Potable water pipelines in the SEQ Water Grid usually have a minimum of one pigging station at each end of the pipeline. The discharge from the pigging process is highly turbid, darkly coloured and potentially odorous water that contains sediments and organic material dislodged from the pipe wall. This type of discharge can be several megalitres in volume and, apart from the need for environmental compliance and aesthetic impacts, may be considered a nuisance if discharged in residential areas.

'"'''' '-~.!-

GEA Mechanical Equipment GEA W estfalia Separator Aust P/ L 47 Northgate Drive Thomastown Victoria 3074 Phone: +61 3 9463 1999 Fax: +61 3 9464 5455 Email: nathaniel barling@geagroup com www.australia .westfalia-separator.com

water SEPTEMBER 2010 87


environmental water management Appropriate Forms of Tenure for Discharge Sites In order to prevent harm to people or property and to protect critical drainage paths, LinkWater must be able to: • construct and/or maintain a clear passage for the discharged water to travel from the discharge point to the end point • construct embankments or other structures to direct the discharged water over flat land and avoid private property which LinkWater has no rights over • access the site for the purpose of maintenance • remove people or property wh ich may be in the drainage path of the discharged water. The most appropriate form of tenure to take over the land between the discharge point and the end point in these cases will be a drainage easement. Easements can provide sufficient access and construction rights as well as authorising LinkWater to restrict the access of people or property which may be harmed by or restrict the flow of the discharged wat er. These rights must be covered in the terms of the easement when it is drafted. The terms of the easement wi ll also need to: • ensure that the easement is of sufficient width to provide an access track along at least one side of the drainage channel for operation of maintenance vehicles (where applicable) • restrict the ability of the landowner to construct any permanent structure on the land wh ich may impede the flow of water • authorise LinkWater and its employees to remove anything from the land which may impede the flow of discharged water. Where a discharge site wi ll only undergo a single planned discharge during the life of the pipeline (e.g. discharging water used in the hydrostatic testing of a pipeline section during construction of a new asset), a lesser form of ten ure or access agreement will be sufficient. An access agreement may be entered into between LinkWater and the landowner setting out the rights and obligations of each party for the single discharge of water along the flow path.

88 SEPTEMBER 201 0 water

[SJ

refereed paper

Where the land along the flow path is owned by the state, a 'memorandum of understanding' may be established with the relevant authority through the Coordinator-General to secure the right to discharge water over this land if obtaining an easement is not appropriate.

The authors would like to acknowledge Luke Hinkfuss and Stuart Baxter from Clayton Utz for their advice regard ing the legal implications of water discharge at common law and under statute.

Conclusion

The Authors

An important element in maintaining bulk water infrastructure is planning for water discharges which may occur during the operational life of the asset. By locating discharge sites appropriately and establishing any additional land req uirements for drainage during the design phase of a project, potential liability under common law as well as future operat ional issues can be reduced or avoided.

Merrianne McAlpine has a Master of Environmental Engineering (Hons) degree from Griffith University. She was at the time of writing a Compliance Officer for LinkWater in Brisbane and is now on maternity leave. Email: merriannemcalpine@iinet.net.au.

To discharge common law duties of care and ensure the effective operation and maintenance of the SEQ Water Grid, critical drainage flow paths will need to be secured w ith permanent forms of t enure. The most appropriate form of tenure will usually be a drainage easement. LinkWater has determined that drainage easements are required for flow paths from balance tank overflows and safety-relief valves because the velocity and volume of water discharged has the potential to cause harm to people and property and the timing of such an occurrence is impossible to predict. Securing easements over the flow paths from pigging stations and preferred draindown points wi ll ensure that the operator will always have the right to discharge water from the pipeline for maintenance purposes. For new bulk water infrastructure projects, land requirements for discharge activities and drainage works can be identified during the design phase so that the appropriat e tenure is established in conjunction with the infrastructure easements. However, additional land requirements for drainage from existing bulk water infrastructure, and the right to discharge water over existing infrastructure easements may need to be addressed retrospectively. These findings may have implications for other operators of existing water infrastructure, or constructors of future infrastructure projects where environmental discharge of water is req uired to operate and maintain the system.

Acknowledgments

Mark Breitfuss is the Manager of Infrastructure Planning for LinkWater in Brisbane. Email: Mark.Breitfuss@linkwater.com. au

References Department of Natural Resources and Department of Environment (DNR & DE) (1998) Stormwater Quality Control Guidelines for Local Government (Queensland) [Electronic]. Available: http://www.epa.qld.gov.au/ environmental_management/water/ environmental_values_ environmental_ protection_water_policy_ 1997/stormwater_ guidelines_for_local_government/ [Accessed: 15 May 2008]. Queensland Environmental Prot ection Agency (2008) ECOACCESS Operational Policy Waste Water Discharge to Queensland Waters [Electronic]. Available: http://www.epa.qld.gov.au/ publications?id=2 272 [Accessed: 15 May 2008]. Queensland Water Commission (2007) Our water: Urban water supply arrangements in South East Queensland, Final Report [online], May. Available: http://www.qwc.qld.gov.au/ Urban+Water+Supply+Arrangements+Report [Accessed 15 May 2008]. Tikkanen, M. W., Schroeter, J . H, Leong, L. Y. C. and Ganesh, R. (2006) Guidance Manual for the Disposal of Chlorinated Water. Available: http://www.pollardwater.com/pdf/pdf_web_ manuals/AWWARF_Dech/or_Guides_Pollard_ dmb.pdf [Accessed 12 May 2008]. Tjandraat madja, G., Gould , S. and Burn, S. (2005) Analysis of Hydrostatic Testing Water, Final Report for Australian Pipeline Industry Association, CS/RO Manufact uring and Infrastructure Technology [online], December. Available: http://www.apia.net.au/wpcontenVuploads/2009/ 10/CSIROHydrostatict estwater.pdf [Accessed 28 Feb 201 OJ.

technical features


f'¡,1

refe r eed paper

environmental water management

FAECAL SOURCE TRACKING IN SEQ: CASE STUDIES W Ahmed, S Toze, T Gardner Abstract This paper outlines the application of faecal source tracking (FST) tools in waterways in Southeast Queensland (SEQ), Australia. FST tools used in the case studies include biochemical fingerprinting , antibiotic resistance analysis, bacterial markers, viral markers and faecal sterols. These tools are predominantly used to identify sewage po llution in environmental waters sourced from defective septic systems or discharges from sewage treatment plants (STPs) . Th e earlier case studies employ library-dependent FST tools where as the recent studies focus more on validation and application of library- independent tools. Several case studies reported the presence of sewage pollution in various aquatic environments and suggest that library-independent tools suc h as bacterial and viral markers are appealing because of t he high specificity and sensitivity of these markers to d ifferentiate and detect sewage and animal faecal pollution. A few case studies also used a combination of tools and suggested that such an approach can compensate uncertainty when one tool fails to produce satisfactory resu lts. These case studies indicate t hat current FST tools can be successfully applied for faecal pollution tracking in environmental waters in SEQ. This is particu larly important for water quality managers who are charged with protecting water quality.

Introduction Pollution from human and animal wastewater is one of the major concerns about aquatic environments that are used for drinking water supply, recreational activities and harvesting seafood worldwide. These concerns are predominantly based on exposure of water users to a w ide array of pathogenic bacteria, protozoa and viruses (Fong et al. 2005; Horman et al. 2004). Microbiological quality of water is commonly assessed by enumerating faecal indicator bacteria such as Escherichia coli and enterococci. The presence of these bacteria in the aquatic environments is used to indicate possible

Table 1. MST tools used in the case studies in SEO, Australia. Tools

Target organisms

Reference

Biochemical fingerprinting

E. coli and enterococci

Ahmed et al. 2005

Antibiotic resistance analysis

E. coli

Ahmed et al. 2008b; Carroll et al. 2005

Library-dependent

Library-independent Sewage-associated HF183

Bacteroides

Ahmed et al. 2008d

Sewage-associated HF134

Bacteroides

Ahmed et al. 2008d

Ruminant-associated CF128

Bacteroides

Ahmed et al. 2008e

Dog-associated BacCan

Bacteroides

Ahmed et al. 2008e

Sewage-associated esp

E. faecium

Ahmed et al. 2008a,c

Sewage-associated JCV and BKV polyomaviruses

Polyomaviruses

Ahmed et al. 201 Oa

Sewage-associated adenoviruses

Adenoviruses

Ahmed et al. 201 Ob

Bovine wastewater-associated adenoviruses

Adenoviruses

Ahmed et al. 201 Ob

Chemical tools Faecal sterols faecal pollution and t he subsequent potential public health risks. However, the presence of these indicators does not indicate whether the pol lution is sourced from sewage or animal wastewater. The identification and assigning of indicat or bact eria found in aquatic environments to sewage and animal faecal pollution is difficult due to their cosmopolitan nature , i.e. t hey are shed in the waste of a wide variety of animals including humans (Field & Samadpour 2007). Over the last decade, researchers have developed a range of faecal source tracking (FST) tools that can be used to disti nguish sewage pollution from animals. These tools are broadly categorised into library-dependent (i.e. phenotypic and genotypic), libraryindependent (i.e. PCR markers), and chemical (i.e. sterois, fluorescent whitening agents). A range of FST tools have been used in Southeast Queensland (SEQ) over the last six years in order to identify the sources of faecal pollution in freshwater, coastal lakes, stormwater and estuarine waters. The aim of t his paper is t o summarise the FST tools used and the results obtained

Current FST tools can be successfully applied.

Sullivan et al. 2010 in key case studies in various aquatic envi ronments in SEQ.

Faecal Source Tracking Tools used in Aquatic Environments in SEQ The majority of the initial FST tools are library-dependent, which requires the development of a "library" of E. coli or enterococci from the faeces of suspected sources of pollution (i.e., sewage or animals) using various genotypic and phenotypic fingerprinting tools. The underlying assumption of the library-dependent tools is that hostspecificity of microorganisms is influenced by selective pressures within t he host animal (Wiggins et al. 1996). Phenotypic and genotypic fingerprints of isolated E. coli or enterococci are then compared to the library to identify t heir likely host sources (Harwood et al. 2000). Another set of more recently developed FST tools do not require the development of a library and are therefore known as library-independent tools. These tools involve detection or quantification of specific marker(s) associated with host sources and microorganisms. Library-independent tools could be categorised into three groups: (1) anaerobic bacterial markers such as sewage-associated Bacteroides (Bernhard & Field 2000); (2) viral markers

water SEPTEMBER 2010 89


~

environmental water management Table 2. Specificity and sensitivity of host-specific markers in SEQ, Australia. Host-specific markers

refereed paper

--------

Number of positive sewage samples/number of sewage samples tested (sample origin)

Sensitivity (%)

Specificity (%)

Reference

Sewage-associated HF183 Bacteroides

52/52 (sewage)

0/155 (various animals)

100

100

Ahmed et al. 2008d

Sewage-associated HF134 Bacteroides

51 /52 (sewage)

7/155 (various animals)

97

95

Ahmed et al. 2008d

Ruminant-associated CF128 Bacteroides

19/20 (cattle)

8/177 (sewage and various animals)

95

93

Ahmed et al. 2008e

Dog-associated Bacteroides

17/20 (dogs)

18/177 (sewage and various animals)

89

Ahmed et al. 2008e

Sewage-associated JCV and BKV polyomaviruses

63/63 (sewage)

1/81 (various animals)

85 100

99

Ahmed et al. 201 Oa

Sewage-associated esp

38/42 (sewage)

0/155 (various animals)

90

100

Ahmed et al. 2008a

Sewage-associated adenoviruses

58/74 (sewage)

0/106 (various animalsl

78

100

Ahmed et al. 201 Ob

Bovine wastewater- associated adenoviruses

7/26 (cattle)

0/154 (sewage and various animals)

73

100

Ahmed et al. 2010b

such as sewage-associated adenoviruses (Fong et al. 2005) and polyomaviruses (McQuaig et al. 2009); and (3) bacterial toxin markers such as pig wastewaterassociated ST1 b (Khatib et al. 2003), cattle wastewater-associated LTlla E. coli toxin gene (Chern et al. 2004), and the sewage-associated enterococcal surface protein (esp) gene found in Enterococcus faecium (Scott et al. 2005). Chemical tools include optical brighteners, caffeine and faecal sterols. A selection of these tools has been used in some of the case studies in SEQ are detailed in Table 1.

Sensitivity and Specificity of Bacterial and Viral Markers used in SEQ Region Sensitivity and specificity are commonly used parameters for the validation of bacterial and viral markers (Field & Samadpour 2007). The sensitivity and

specificity of markers are determined as: sensitivity = a/(a + c) and specificity = d/(b + d), where 'a' is true positive (samples were positive for the marker of its own species), 'b ' is false positive (samples positive for the marker of another species), 'c' is false negative (samples were negative for the marker of its own species), 'd' is true negative (samples were negative for the marker of another species). High specificity and sensitivity are desirable for the accurate identification of polluting source(s) when bacterial and viral markers are used as tools for FST studies. A number of research studies evaluated the sensitivity and specificity of the bacterial and viral markers by screening a large number of sewage and animal faecal samples with in the SEQ reg ion (Table 2). Sewageassociated markers such as Bacteroides HF183, E. faecium esp , adenoviruses and polyomaviruses were highly specific to

sewage and therefore, can be considered as suitable for the detection of sewage pollution. Sewage-associated Bacteroides HF183 and polyomaviruses also demonstrated high sensitivity ratings indicating these markers are quite sensitive for t he detection of faecal pollution in aquatic environments. In contrast , sewage-associated and bovine wastewater-associated adenoviruses showed lower sensitivity indicating these markers alone may not be sufficient to identify the sources of faecal pollution with appropriate sensitivity.

Faecal Source Tracking Case Studies in Aquatic Environments in SEQ Region Table 3 shows the FST tools used and results obtained in ten case studies undertaken in SEQ. In case study 1, urban creek water samples were tested

Table 3. Faecal source tracking case studies undertaken in SEQ, Australia.

----

Case Location study no

Types of aquatic environment

Tools used

Likely sources of faecal pollution

Eudlo Creek, Maroochydore

Freshwater creeks

Biochemical fingerprintinga

Sewage pollution via septic tanks, Ahmed et al. 2005 animals such as chickens and ducks

2

Bonogin Valley and Tallebudgera Creek, Gold Coast

Freshwater creeks Antibiotic resistance analysis3

3

Bergin Creek, Four Mile Creek and River Oaks Drive in Pine Rivers Shire

Stormwater runoff

4

Tooway Lake, Caloundra

5

Reference

Sewage pollution via septic tanks, wild animals

Carroll et al. 2005

Biochemical fingerprintinga sewage-associated HF183b and HF134b PCR

Sewage pollution via septic tanks, wild animals

Ahmed et al. 2007

Coastal lake

Biochemical fingerprintingâ&#x20AC;˘ and antibiotic resistance analysis3

Sewage pollution via STP, waterfowl

Ahmed et al. 2008b

Ningi Creek, Caboolture

Brackish waters

Sewage-associated HF183b, HF134b, Sewage pollution via septic tanks, esf}', ruminant-associated CF128b, cattle and dog faecal pollution dog-associated BacCan~ PCR

Ahmed et al. 2008e

6

Ningi Creek, Caboolture

Brackish waters

Sewage-associated es{fa PCR

Sewage pollution via septic tanks

Ahmed et al. 2008c

7

Bergin, Four Mile and River Oaks Stormwater runoff Drive Creek in Pine Rivers Shire

Sewage-associated Bacteroides HF183b and HF134b PCR

Sewage pollution via septic tanks

Ahmed et al. 2008d

8

Maroochy River, Maroochydore

Estuarine water

Sewage-associated JCV and BKV polyomavirusesb PCR

Sewage pollution via STP and stormwater drains

Ahmed et al. 201 Oa

9

Maroochy River, Maroochydore

Estuarine water

Sewageb - and bovineb wastewater-associated adenoviruses

Sewage poll ution via STP and stormwater drains and bovine faecal faeces

Ahmed et al. 201 Ob

10

North Maroochy River, Maroochydore

Freshwater creeks

Faecal sterols

Sewage pollution via septic tanks, wild animals

Sullivan et al. 2010

a quantitative; b qualitative

90 SEPTEMBER 2010 water

technical features


r-~1

refereed paper

to identify sewage pollution in Eudlo Creek, Maroochydore. A secondary aim was to identify faecal pollution originating from domestic and wild animals. Biochemical fingerpri nting libraries comprising of 4,057 enterococci and 3,728 E. coli isolates from horses, cattle, sheep, pigs, ducks, chickens, deer, kangaroos, dogs and septic tanks were used to identify the sources of unknown environmental E. coli and enterococci using cluster analysis (Ahmed et al. 2005). E. coli and enterococci libraries were capable of identifying the sources of more than 65% of the isolated indicator bacteria from the studied creek. The authors reported that the sewageassociated E. coli and enterococci isolates in the studied creek originated from defective septic tanks and as well as animal sources. Antibiotic resistance analysis was used in case study 2 to determine the significance of septic systems as a major contributor to faecal pollution in two mixed land use catchments , Bonogin Valley and Tallebudgera Creek, in the Gold Coast Region (Carroll et al. 2005). Antibiotic resistance patterns were established from 717 known E. coli isolates obtained from septic tanks and faeces from domesticated, livestock and wild animals. Discriminant analysis was used to differentiate between the antibiotic resistance patterns of isolates from various sources, and to classify each isolate from water (unknown source) into a source cat egory. The results suggested the presence of sewage pollution within the investigated catchments originated from septic tanks.

environmental water management In case study 3, storm water samples were collected from Bergin Creek, Four Mile Creek and River Oaks Drive to determine whether the stormwater was polluted with sewage from possible defective septic systems (Ahmed et al. 2007). A battery of tools consisting of biochemical fingerpri nti ng of E. coli and enterococci, sewage-associated Bacteroides HF183, HF134 and sewageassociated esp markers were used to detect sewage pollution in the nonsewered, residential catchments studied. The source of 105 E. coli biochemical phenotypes (BPTs) and 93 enterococci BPTs were identified in wat er samples from River Oaks Drive catchment. Of these, 10% and 9% were identified as sewage-associated E. coli and enterococci BPTs, respectively. Similarly, of the 83 E. coli BPTs and 93 enterococci BPTs from the Bergin Creek catchment site, 8% E. coli BPTs and 9% enterococci BPTs were identified as sewage-associated isolates. The number of E. coli and enterococci assigned to sewage-associated in the Four Mile Creek site were 4% and 3%, respectively. Sewage-associated HF183, HF134 and esp markers were detected in water samples however, the librarydependent (i.e. biochemical fingerprinting) and library-independent (PCR markers) tools were not always in agreement in detecting sewage pollution in water samples. This study demonstrated t he value of a combination of tools for faecal pollution tracking to obtain a better understanding regarding the pollution sources.

Multiple bacterial markers (i.e. sewageassociated Bacteroides HF183, HF134, esp markers, ruminant-associated markers, and dog-associated markers) were used to determine the sources of faecal pollution in case study 5. The specificity of these markers were determined by testing large number of faecal samples from sewage/ septage, ducks, kangaroos, cattle, horses, dogs, chickens, pigs, pelicans, goats, deer, wild birds and sheep (Ahmed et al. 2008e). Most of the markers showed high specificity (> 0.90) except Bacteroides dog-associated markers which showed low specificity. At least one host-specific marker was detected in 14 (87%) out of 16 water samples. Sewage-associated Bacteroides HF183 and HF134 markers were detected in 9 (56%) and 6 (37%) samples, respectively. This figure for sewage-associated esp marker was also 6 (37%). Ruminant-associated markers CF128 were detected in 11 (69%) samples whereas dog-associated markers BacCan were detected in 5 (31 %) samples. Among all markers, Bacteroides HF183 and esp performed well in terms of specificity and identifying the sources of sewage pollution. However, a combination of multiple sewage-associated markers provided greater reliability regarding the presence/ absence of sewage pollution when one marker was not sufficient to identify sewage pollution. Quantitative PCR (qPCR) was used to estimate the levels of sewage-associated esp markers in case study 6. Environmental samples (n = 16) were collected after storm events and tested

l - 300 - Li26 - Li23 www .a mi a d. co m .a u

water SEPTEMBER 2010

91


environmental water management using qPCR for the quantitative detection of sewage pollution (Ahmed et al. 2008c). The specificity of the esp marker to distinguish between sewage and animal faecal pollution was determined by screening a large number of sewage and animal faecal samples. The esp marker was detected in 90.5% of combined sewage and septic tank samples (n = 42) and was not detected in any of the faecal samples (n = 155) from the nontarget animals tested. Of the 16 samples tested, six (38%) were positive for the esp marker, and the number ranged between 1.1 x 102 and 5.3 x 102 gene copies/100 ml of water. The evidence presented in this study demonstrated that the E. faecium esp markers appears to be host-specific and promising for sewage pollution tracking in environmental waters in SEQ. Viral markers (i.e. sewage-associated JCV and BKV polyomaviruses, sewageassociated adenoviruses, and bovine wastewater-associated adenoviruses) were used to determine the sources of faecal pollution in case studies 8 and 9. The host-specificity of these viral markers was determined by screening wastewater and faecal samples from non-target sources such as chickens, dogs, ducks, kangaroos, wild birds, cattle, pigs and sheep. All the viral markers exhibited high host-specificity (Ahmed et al. 201 0a,b). Of the 20 samples tested for sewage-associated BKV and JCV polyomaviruses, five (25%) were positive, indicated the presence of sewage in various sites on the Maroochy River. Of the 20 samples tested for sewage-associated and bovine wastewater-associated adenoviruses, four (20%) were positive for sewageassociated adenoviruses and two (10%) were positive for bovine wastewaterassociated adenoviruses. The authors concluded that viral markers appear to be highly host-specific for detecting sewage pollution in the studied coastal river. The presence of viral markers in river water samples indicate potential public health risks as the studied river is used for recreational activities including swimming, fishing and water sports. Faecal sterols were used to determine the sources of sewage pollution in the case study 10. In all, 36 water samples were collected from six sites on six occasi.ons and the concentration of sterols were determined. The stanols concentration in water samples generally increased with increased catchment runoff. After moderate rainfall , high coprostanols levels found in water samples indicated sewage pollution via

92 SEPTEMBER 2010 water

defective septic systems. In contrast, it appears that during dry weather sewage pollut ion is not occurring in the study catchment. Sterol profiles also pointed to a cattle farm causing pollution during modest catchment runoff. The method used in this study was able to identify t he sources of faecal pollution to the catchment due to rainfall.

Conclusions and Future Directions This series of case studies conducted in SEQ, Australia, has demonstrated the successful application of FST tools in a range of aquatic environments. The primary question that arises in many situations is whether aquatic environments contain sewage pollution. Sewage pollution is usually considered to represent the greatest health risk (Field & Samadpour 2007, Leclerc et al. 2002). Library-dependent tools such as biochemical fingerprinting and antibiotic resistance analysis, as illustrated in case studies 1 and 2 can be effective in source identification of faecal indicators. However the need to generate a large source library, and potential concerns over validity of a library beyond the spatial and temporal constraints in which it was derived from can make librarydependent tools both time consuming and expensive. Library-independent source tracking tools, such as host-specific PCR marker approaches, may be more robust as, in theory, these markers may be more temporally and spatially stable than libraries. The case studies in this paper indicate that the tested markers indeed exhibit similar sensitivity and specificity in the SEQ region. Most of the markers showed high specificity suggesting the suitability for distinguishing between the sewage and animal faecal pollution although the sensitivity was not always high. Nonetheless, the appl ication of an array of markers (i.e., sewage-associated Bacteroides and viruses) and/or combination of FST tools (i.e., librarydependent and library-independent) can compensate for any uncertainty created through the use of a single marker or a specific tool. While there is an increasing knowledge on the degradation, sedimentation, and transport of these FST markers (Bae & Wuertz 2009, Okabe & Shimazu 2007, Walters & Field 2006, Walters & Field 2009), the overall understanding is incomplete, and in most cases, untested in real life situations. Preferential transport may result in some markers

[Isl

refereed paper

behaving differently compared to the t raditional faecal indicators and pathogens that are of ultimate concern (Dick et al. 201 0; Stapleton et al. 2009). Nonet heless, collectively, these case studies indicate that current FST tools can be successfully applied for source identification and can be used for meaningful and productive management decisions. However, there is a need for significant refinement of these tools, and a continued investment in research to achieve these improvements is required . Despite this, FST tools can and are being used to improve water quality outcomes, even in its current developing forms.

The Authors

Dr Warish Ahmed has had a career in identifying the sources of faecal pollution in environmental waters. He is currently working as a water microbiolog ist at CSIRO Land and Water, St Lucia, Qld. Email: Warish .Ahmed@csiro.au. Ted Gardner is Principal Scientist with CSIRO Land and Water. Dr Simon Toze is a Research Group Leader with CSIRO Land and Water in the Urban and Industrial Water Research Theme. He also leads the Indirect Potable Recycling research area for the CSIRO Water for a Healthy Country Flagship.

References Ahmed, W., Neller, R. & Katouli, M. 2005, ' Hostspecies specific metabolic fingerprint database for enterococci and Escherichia coli and its application to identify sources of fecal contamination in surface waters', Applied and Environmental Microbiology, 71, pp. 4461-8. Ahmed, W., Stewart, J. , Gardner, T., Powell, D., Brooks, P., Sullivan, D. & Tindale, N. 2007, 'Sourcing fecal pollution: A combination of library-dependent and library-independent methods to identify human fecal pollution in non-sewered catchments', Water Research, 41, pp, 3771-9. Ahmed, W., Stewart, J., Powell, D. & Gardner, T. 2008a, 'Evaluation of host-specificity and prevalence of enterococci surface protein (esp) marker in sewage and its application for sourcing human faecal pollution', Journal of Environmental Quality, 37, pp. 1583-8. Ahmed, W., Hargreaves, M., Goonetilleke, A. & Katouli, M . 2008b, 'Populat ion similarity analysis of indicator bacteria for source prediction of fecal pollution in a recreational coastal lake', Marine Pollution Bulletin, 56, pp. 1469-75. Ahmed, W. , Stewart, J. , Gardner, T. & Powell, D. 2008c, 'A real-time polymerase chain reaction assay for the quantitative detection of the human-specific enterococci surface protein marker in sewage and environmental waters', Environmental Microbiology, 10, pp. 3255-64.

technical

eatures


r e f e r eed pape r

Ahmed, W., Stewart, J., Powell, D. & Gardner, T. 2008d, 'Evaluation of Bacteroides markers for the detection of human faecal pollution', Letters in Applied Microbiology, 46, pp. 23742. Ahmed, W., Powell, D., Goonetilleke, A. & Gardner, T. 2008e, 'Detection and source identification of faecal pollution in nonsewered catchment by means of host-specific molecular markers', Water Science and Technology, 58, pp. 579-586. Ahmed, W., Wan, C., Goonetilleke, A. & Gardner, T. 2010a, 'Evaluation of human associated JCV and BKV polyomaviruses for the detection of sewage pollution in a coastal river', Journal of Environmental Quality (accepted). Ahmed, W., Goonetilleke, A. & Gardner, T. 2010b, ' Human and bovine adenoviruses for the detection of source-specific fecal pollution in coastal waters in Australia' , Water Research (accepted). Bae, S. & Wuertz, S. 2009, 'Rapid decay of hostspecific fecal Bacteroidales cells in seawater as measured by quantitative PCR with propidium monoazide', Water Research, 43, pp. 4850-9. Bernhard, A.E. & Field, K.G. 2000, 'A PCR assay to discriminate human and ruminant feces on the basis of host differences in BacteroidesPrevotella genes encoding 16S rRNA', Applied and Environmental Microbiology, 66, pp. 4571 - 4574. Carroll, S., Hargreaves, M. & Goonetilleke, A. 2005, ' Sourcing faecal pollution from onsite wastewater treatment systems in surface waters using antibiotic resistance analysis', Journal of Applied Microbiology, 99, PP. 47182. Chern, E.C. , Tsai, Y.L. & Olson, B.H. 2004, 'Occurrence of genes associated with enterotoxigenic and enterohemorrhagic Escherichia coli in agricultural waste lagoons', Applied and Environmental Microbiology, 70, pp. 356- 362. Dick, l.K., Stelzer, E.A., Bertke, E.E. , Long, D.F. & Stoeckel, D.M, 201 0, 'Relative decay of Bacteroidales microbial source tracking markers and cultivated Escherichia coli in freshwater microcosms', Applied and Environmental Microbiology, 76, pp. 32553262. Field, K.G., & Samadpour, M. 2007, 'Fecal source tracking: the indicator paradigm and managing water quality', Water Research, 41 , pp. 3517-38. Fong, T.T., Griffin, D.W. & Lipp, E.K. 2005, 'Molecular assays for targeting human and bovine enteric viruses in coastal waters and their application for library-independent source tracking', Applied and Environmental Microbiology, 71, pp. 2070-8. Harwood, V.J., Whitlock, J., & Withington, V. 2000, 'Classification of antibiotic resistance patterns of indicator bacteria by discriminant analysis: use in predicting the source of fecal contamination in subtropical waters', Applied and Environmental Microbiology, 66, pp. 3698-704. Horman, A. , Rimhanen-Finne, R. , Maunula, L., von Bonsdorff, C-H., Torvela, N., Heikinheimo, A. & Hanninen M.-L. 2004, 'Campylobacter spp. Giardia spp. Cryptosporidium spp. Noroviruses and indicator organisms in surface water in south-western Finland 2000-2001 ', Applied and Environmental Microbiology, 70, pp. 87-95. Khatib, L.A., Tsai, Y.L. & Olson, B.H. 2003, 'A biomarker for the identification of swine fecal pollution in water using the STII toxin gene

environmental water management from enterotoxigenic E. coli', Applied Microbiology and Biotechnology, 63, pp. 231- 238. Leclerc, H. , Schwartzbrod, L. & Dei-Cas, E. 2002,' Microbial agents associated with waterborne diseases', Critical Reviews in Microbiology, 28, pp. 371-409. McQuaig, S.M., Scott, T.M. , Harwood, V.J., Farrah , S.R. & Lukasik, J.O. 2009, 'Quantification of human polyomaviruses JC virus and BK virus by Taqman Quantitative PCR and comparison to other water quality indicators in water and fecal samples', Applied and Environmental Microbiology, 75, pp. 3379-88. Okabe, S., & Shimazu, Y. 2007, 'Persistence of host-specific Bacteroides-Prevotella 16S rRNA genetic markers in environmental waters: effects of temperature and salinity', Applied Microbiology and Biotechnology, 76, pp. 93544. Scott, T.M., Jenkins, T.M., Lukasik. J. & Rose, J.B. 2005, ' Potential use of a host associated molecular marker in Enterococcus faecium as an index of human pollution ', Environmental Science and Technology, 39, pp. 283-287. Stapleton, C.M., Kay, D., Wyer, M.D., Davies, C., Watkins, J., Kay, C., McDonald, A.T ., Porter,

J. & Gawler, A. 2009, 'Evaluating the operational utility of a Bacteroidales quantitative PCR-based MST approach in determining the source of faecal indicator organisms at a UK bathing water', Waler Research, 43, pp. 4888-4899. Sullivan, D., Brooks, P., Tindale, N., Chapman, C. & Ahmed, W. 2010, 'Application of fecal sterols to identify human fecal pollution in non-sewered catchments', Water Science and Technology, 61, pp. 1355-1361 Walters, S.P. & Field, K.G. 2006, 'Persistence and growth of fecal Bacteroidales assessed by bromodeoxyuridine immunocapture', Applied and Environmental Microbiology, 72, pp. 4532-9. Walters, S.P. & Field, K.G. 2009, 'Survival and persistence of human and ruminant-specific faecal Bacteroidales in freshwater microcosms', Environmental Microbiology, 11, pp. 1410-21. Wiggins, B.A. 1996, 'Discriminant analysis of antibiotic resistance patterns in fecal streptococci a method to differentiate human and animals sources of fecal pollution in natural waters', Applied and Environmental Microbiology, 62, pp. 3997-4002.

Client Says Sell

4 off 55kW aspirators fitted with additional blowers. By-Jas is proud to sell on behalf of one of Australia's p rem ier Mea t Wo rks located i n metropo l ita n Brisbane . Client paid well in excess of $ 100,000, available immediately after 12 months in service for $10,000 each .

Contact details sjaski@byjas.com.au or 0418 177 178.

water

SEPTEMBER 2010 93


~

water industry capacity development

ref e r eed pape r

SKILLS SHORTAGE IN THE WATER INDUSTRY AR Ladson, KA Austin Abstract In Australia, issues of an ageing workforce and skills shortages are affecting most businesses now and are projected to worsen. These issues are particularly severe in the water industry and will not be 'solved' by the current global financial crisis. Responding to these issues requires strategies around recruitment and retention. These are likely to include increasing the number of graduates, introducing flexible work practices and encouraging workers to delay retirement. The water industry is aware of these issues and there is already a range of strategies being developed including WICD (Water Industry Capacity Development) and the Water Industry Skills Taskforce. These initiatives deserve the support of water professionals and organisations. This paper includes: • An introduction to skills shortage, labour shortage and ageing workforce issues; • Two simple models of the labour force within an industry and related to an employer; • General strategies suggested by these models; • A summary of activities within the water industry to address ageing workforce and skills shortages issues. Earlier versions of this paper were presented at industry conferences (Ladson and Austin, 2009a,b).

Skills Shortage/Ageing Workforce: The Basics What is a skills shortage? According to the Productivity Commission: Labour shortages refers to difficulties experienced by employers generally in employing particular occupations at what were previously adequate wages and conditions - the demand for people in these occupations at a given wage, exceeds their supply. Such specific skilled labour shortages are ongoing features of any market economy as shifts in consumption and

94 SEPTEMBER 2010 water

Retirements-+People employed in an Industry (e.g. the Water Industry)

Leakage out_. Emig ratio~

People who leave temporarily (Maternity leave Study leave Overseas travel)

Figure 1. Simple model of employment within an industry. production occur (for example, shortages of geologists during the mining boom and bricklayers during the housing boom). Generally, such specific occupational skill shortages (and excesses) are transitory, as training institutions respond to demand, industry structures change and relative occupational wage rates vary. Productivity Commission (2004, p69)

From an economic perspective, a labour shortage is likely to be a short-run imbalance as industry adjusts to changes in demand and supply (Trendle, 2004) unless there are external factors that prevent the situation coming into balance. We are assuming that 'labour shortage' and 'skills shortage' are different terms for the same issue. An ageing workforce can lead to a skills shortage if the number of experienced people leaving an industry through retirements is greater than can be replaced. There is talk of a skills shortage in the water industry. Two simple models can be used to understand the situation and possible actions: 1) A model of employment within a particular industry; and 2) A model of employment by a particular employer.

Strategies are being developed.

MODEL 1. Employment Within an Industry There has been much discussion of shortage of workers in particular industries. Most of this has just focused on demand e.g. Barrett (2008), where retirements and numbers leaving the industry are summed to produce a projected "gap" in the workforce. In fact, there will only be a skills shortage if there is an imbalance between demand and supply. A simple model of employment within a particular industry is shown in Figure 1. The inputs are: graduates, skilled immigrants, leakage in (people transferring from other industries) and people retu rning from temporary departures (e.g. maternity leave). Outputs are: retirements , leakage out (people transferring to other industries), temporary departures (e.g. maternity leave) and, emigration (people leaving the industry to live in another country). The success of the Australian water industry brings w ith it the consequence that professionals are now in demand internationally, for example, in areas such as the Middle East.

Over time, the change in the number of people working in an industry will be the difference between the inputs and the outputs.

technical features


[iil

r e f e r ee d p ape r

water industry capacity development

The need for workers in a particular industry can also change over time; for example, the number of people employed in Agriculture decreased by about 25% following the 2002/03 drought when agriculture output also declined by about 25%. Similarly there has been a long term increase in the size of the consu lting segment of the water industry as the techn ical workforce withi n government agencies has declined. There are also ways of changing the amount of work that gets done without chang ing the number of people employed. For example, the number of hours worked may change through paid or unpaid overtime or through increasing or decreasing part time work. Productivity also changes with time particularly with the introduction of new technology (Richardson, 2007), this may decrease the demand for workers. Activity may also be: • Outsourced internationally wh ich will decrease domestic demand, or • In-sourced which will increase demand for workers. If we sum the inputs, outputs and change in demand over time then the three possible situations are:

1. The workforce demand and supply are in balance

2. There is oversupply of workers 3. There is a labour shortage Note that the case of a balance between demand and supply is probably unusual. In most cases there wi ll be a shortage or an oversupply that will encourage people to enter or leave the workforce for a particular industry without the problem becoming newsworthy. These types of dynamic adjustments are a normal part of workforce behaviour in a complex economy like Australia's. However, if the shortage becomes so large, or the pool of available workers so small, that labour demands are not easily met, then there may be a case for intervention by government or employer groups.

Employment in the water industry Is there a labour shortage in the water industry? Recent reporti ng suggests there is and that intervention may be requi red. • The Water Services Association of Australia (Barrett, 2008) projects large ski lls shortages in the water sector and later reporting by Leslie (2008) suggests that skills shortages may be exacerbated when additional employers are considered including: reg ional water utilities, the irrigation sector, local government (e.g. stormwater), the construction industry associated with the water industry and environmental consu lt ants.

particularly Civil Engineers which is a discipline widely employed in the water industry (Kaspura, 2008). For example, the proportion of Civil Engineering graduates actually seeking full time employment is very low compared to the proportion of all graduates seeking full time employment i.e. Civil Engineering graduates are in demand. • A report by the Department of Employment and Workplace Relations (2005) predicts that all industries will be affected by ageing workforce issues over the next 5 years with shortfall of 195,000 workers. • Doughney (2003) suggests that labour supply problems are likely and that industries requiring specialised skills will be the first to be affected. • A SWOT analysis on Australian Hydrology suggested that skills shortages were an emerging issue (Nathan, 2007). • Review of Cap Implementation for the Murray- Darling Basin Authority (IAG, 2008) noted that skills shortages continue to be an issue facing effective monitoring of the Cap. • A report by DEHWA (2009) not ed that skills shortages related to hydrology and wat er modelling were limiting progress on initiatives related to understanding and responding to cl imate change, environmental management and new technologies. • The Water Sector has one of the highest proportion of mature aged workers (those aged between 45 and 60) (ABS, 2005). • The Stat e Services Authority of Victoria projects significant shortages in the water area of the public sector and in infrastructure project management.

Bi~Tector

"The Oxidation Process that totally Self-Cleans"

ANALYTICAL SYSTEMS LIMITED

On-Line Liquid Analysers for reliable TOC, TN, TP Measurement Plus!! OOP, COD, BOD, TC, TIC BioTector Liquid Analysers are specifically developed for continuous analysis in the harsh on-line environment, reliably measuring samples containing salts, particulates, fats, oils and greases. •

Patented Self-Cleaning Technology provides optimal solutions for on-line analysis.

Recognised by major industrial corporations as the Most Reliable on-line liquid analysers on the market - up to 86,000 measurements per year and typically 99. 7% Uptime.

Lowest maintenance in the industry, service frequency twice per year.

• The National Water Commission reports that 50 % of water utility staff will retire in the next 10 years.

Dramatic payback on product loss, treatment costs and maintenance costs.

• Frost (2009) found that 73% of respondents to a survey of floodplain managers were having problems recruiting qualified staff with 62% taking between 3 to 12 months to fill a vacancy and 24% taking greater than 12 months. Skills shortages were considered the top priority issue, being mentioned by all respondents.

Guaranteed to handle the most demanding applications.

• A National Water Skills Aud it suggested that 40,000 skilled new entrants will be required by the water industry by 2018 because of resignations (25%), retirements (25%) and growth in the water sector (50%) (ICEWARM , 2008).

• A report by Engineers Australia shows that based on surveys and indirect evidence there is a shortage of engineers,

I

Pryde Measurement Pty Ltd Toll Free : 1800 688 21 1

www.pryde.com.au

water SEPTEMBER 2010 95


water industry capacity development Ageing workforces and skills shortages lead to increased costs for business including:

80

~

°c' 70

• Higher staff turnover

·B,.

• Extra work that may be required to maintain the quality of products produced by inexperienced workers .

·.; -~ 60

In addition, businesses are likely to have difficulty maintaining production because of a lack of workers.

ref e r eed paper

90

• Higher wages • Increased costs of recruiting

[I]

... ....

-==

- - - -~

~

2

~

so

~

40

Possible responses if there is a labour shortage? This model suggests several possible responses to a labour shortage:

30 1997 -

UK -

1998

1999

New Zealand -

2000

2001

2002

Australia -OECD Ave -

2003 United States -

2004

2005

France

• Increase the number of graduates • Increase the net immigration of skilled workers for that particular industry

Figure 2. Participation rates for men aged 55-64 years (0ECD, 2006).

• Decrease retirements • Increase leakage in • Decrease leakage out • Shrink the demand for workers by cancelling projects or delaying projects • Outsource work internationally • Introduce flexible work practices to allow people to leave temporarily and return to work or to maintain the balance between work and other commitments • Increase the number of hours worked by increasing paid or unpaid overtime or moving people from part-time to full-time work • Improve productivity per worker through training or introducing new technology • Change work arrangements so that people with readily available skills do some of the work previously done by workers with skills in short supply.

Particular Issues in the Water Industry This section outlines some workforce issues for the water industry in particular.

Retirements Some reports (e.g. Barrett, 2008) suggest there will be a large number of retirements in the water industry over the next few years. If the age profile of an organisation is such that it includes people with ages evenly spread between 22 to 62 years i.e. 40 years ; then you wou ld expect 1/40 = 2.5% of t he workforce to retire each year. The proportion of the workforce

96 SEPTEMBER 2010 water

greater than 45 would be about 17 x 2.5 = 42.5%. The median age of workers would be about 42 years.

• Develop recruitment strategies specifically targeted to people who have retired from fulltime work.

Currently, in the water industry the workforce is not evenly spread across age ranges; there are more older workers which means retirement rates are increased. For example 49.2% of the workforce is greater than 45 years old compared to 40.2% for the all industry median and the retirement rate is around 5% per year (Barrett, 2008).

Note that increasing participation rates amongst people aged 55-64 is a real possibility. Many countries have higher participation rates, including some with similar economic circumstances to Australia (Figure 2). For example, the participation rate for men aged 55-64 in New Zealand in 2005 was 80% compared with Australia's at 66% in the same year. The participation rate for mature-age women in New Zealand was 18 percentage points higher in the same year and has increased rapidly since 1997 (Costello, 2007). The pool of workers in these age categories are projected to increase rapidly. By 2012 t he proportion of workers in Australia's labour force aged 55 or older wi ll increase by 12.7 per cent while the number of workers aged 25-54 will only increase by 5.5 per cent. More than one in five workers will be aged 55 or older (McDonnell, 2009).

The high retirement rate means there is a larger than normal loss of experienced workers. Strategies to decrease the impact of high retirement rates in the water industry can be summarised in three main areas: • Reduci ng retirements by water sector employees • Provide flexible working arrangements e.g. part t ime work, additional leave • Allow people to retire from the work they don't want to do while encouraging them to continue the work they like • Increasing the size of the pool of retirees that are interested in working • Increasing the number of recruits in the water industry from the pool of retirees

Table 1. Median salaries in 2007 (Barrett, 2008).

Male Female All

Water industry

Australia all industry

$59,000 $55,800 $57,400

$75,300 $60,000 $68,800

Remuneration Work by WSAA (Barrett, 2008) suggests that salaries are lower in the water industry t han in other industries (Table 1). Although the figures are three years old there is little to suggest that the differential has altered. Th is is likely to lead to 'Leakage out' as people move to industri es where they are paid more. Work by APESMA suggests that " Remuneration rated as the most important attribute of an employer of choice and the most significant factor by employees considering their next career

technical features


~

refereed paper

water industry capacity development

move" and "More than 75% of respondents to an APESMA survey at West ern Australia's Water Corp said their remuneration was inadequate, and nearly 60% intended to leave within five years" (Bozik, 2008). Frost (2009) found that "there was strong agreement that a reason for the skills shortage [in floodplain management] was the lack of appropriate remuneration". A particular issue at present is the high salaries being offered in the mining industry, which is keen to attract graduates. The latest ABS (2010) statistics show that total weekly earnings of all employees (full time and part time) in the mining industry are $500 per week higher than any other industry. These findings suggest that salaries in the water industry will have to increase or the skills shortages will worsen.

Working conditions Other areas where the water industry varied substantially from averages across all industries were: • Employment status: 93% of employees were full time compared to 75% for the average across all industries. This could suggest a lack of flexibility in work pract ices and also suggests there is less scope to increase the number of hours worked per employee to respond to labour shortages • Tenure: almost 50% of the water industry employees have more than 10 years tenure compared to 33.7% for all industry averages • Resignation rates: the median resignJ:!tion rate was 8.1 % compared to all industry median of 14. 7%. However resignation rates for Civil Engineers were 20.7%, much higher than the water industry median, suggesting there may be retention issues within particular job roles. • Recent data suggests the level of staff turn-over has also increased markedly across the industry (Palm Consulting Group, 2008).

that the number of engineers available to undertake work on infrastructure projects, as a ratio of the cost of the projects, had approximately halved between 1994 and 2006. In 1994 there were 26.3 new engineering graduates for each $100 million in engineering construction activity and this decreased to 12.3 new engineering graduates for each $100 million in engineering construction activity in 2006 (Kaspura, 2008). Capital works are also increasing rapidly , for example, the forecast national capital works program in 2009 is conservatively at least four times the level of the program delivered in 2000 (Sturdy, 2009). One of the reasons that there are so few engineering graduates is the high university dropout rate. About 12,000 Australian nationals commence degrees in engineering each year but only about 6,000 complete their courses (King, 2008). Perhaps teaching quality at Universities has declined. Since 1996 there has been a large increase in average class sizes and the full-time equivalent student to teaching staff ratio has risen from about 14 to 21 (King, 2008). Note that even if there is a move to increase the number of graduates, there wil l be a substantial lag between enrolling more students in university courses and having these students complete and be ready for work.

Immigration of skilled workers Another important source of workers to an industry is skilled migrants. This is particularly significant in engineering where there are a large number of permanent and temporary workers arriving each year with a recent rapid increase. In 2006-07 the

Tubesettlers

Work by the Department of Employment and Workplace Relations (2005) also showed that Civil Engineers, as a group, had a higher median age than average. This suggests there is a high leakage rate amongst Civil Engineers and on-going loss of you nger professionals.

, For Desalination Plants (Installed in Sydney and Brisbane)

And other applications , PP material is approved for high standards of potable water

Graduates Graduates are often assumed to be the key source of new skilled workers in an industry and a pool of new graduates will clearly be important to overcome skills shortages. Engineering graduate numbers are tracked by the Engineers Australia (Kaspura, 2008). Data is available from 2001 to 2006 and show that the number of domestic students completing bachelors degrees in engineering has been reasonably constant at about 6,000 per year. Civil Engineering, an important discipline for the water industry, however, experienced a steadily declining share in graduations falling from 899, or 15.4% of graduates in 2001 to 686, or 11.4% of graduates in 2006 (Kaspura, 2008). Although there is little data available it is also likely that many of these graduates find work outside the engineering profession. About 22,000 people identified themselves as Civil Engineers in the 2006 census (2,000 women and 20,000 men) (Kaspura , 2008). If we assume a 5% retirement rate then about 1,100 Civil Engineers will be leaving the workforce every year, around double the number of new domestic Civil Engineering graduates. The total demand for Civil Engineers is likely to be much greater than just replacing retirements given the current and planned large infrastructure projects. Other data shows

, Flexible dimensions ,

Easy handling can be

assembled on site , Sophisticated support

Dandenong VIC 3175 Australia tel: (61)(3) 9793 7269 email: BRUN0@2h.com.au

www.2h.com.au water SEPTEMBER 2010 9 7


water industry capacity development overall total of engineering immigrants was 6,090; 4,120 were permanent and 1,970 on temporary 457 visas. About 2,000 of the permanent immigrants are 'on-shore' applicants, many of which are international students who have completed their engineering degrees in Australia.

'Invisible' skills shortages There are also skills shortages that that will not be manifest in the form of increased vacancies. If firms believe they cannot recruit skilled workers they may adopt less efficient technologies and work methods. This may result in lower quality outputs, reduced living standards and decreased international competitiveness, the so called 'low skills, bad jobs trap' (Booth and Snower, 1996; Richardson, 2007). Most people in the water industry would agree that we should aim for high skills, good jobs and quality outputs.

Model 2: Employment by a Particular Employer When considering employment by a particular employer there are a few additional 'stocks and flows' that are worth considering (Figure 3). Inputs: Graduates, recruitment of experienced staff, retiree recruitment, people returning from temporary departures (e.g. maternity leave). Outputs: Retirements, resignations, people leaving to temporary departures (e. g. maternity leave).

98 SEPTEMBER 2010 water

refe reed p a p e r

Leakage In

These numbers can be compared to engineering graduates. In 2006 there were 5,853 new baccalaureate graduates and 4,120 new migrant engineers. If the temporary engineers on 457 visas are included, the supply of new degree qualified engineers is 11,943 and migration accounts for 51 % of the new supply. Considering just Civil Engineers, in 2007-08 there were about 2,000 immigrants; 809 permanent and 1,190 on temporary 457 visas. This is more than double the number of domestic graduates. Considering both domestic and immigrant Civil Engineers, the total number of entrants to the workforce in 2007-08 was 2,700, about 12% of the existing Civil Engineering population. This suggests that Australia is underinvesting in educating engineers (King, 2008). Providing more engineering places in universities and decreasing the dropout rate are clearly st rategies that should be considered in addressing the ski lls shortage.

[Ji]

Graduate recruitment

Figure 3. Simple model of employment within an industry by an individual employer. There may also be a change in size of an employer, for example, t he tech nical service area of authorities has tended to decline over time, while the number of employees in consulting companies has tended to increase. Apparent skills shortages experienced by individual employers are likely to be less severe than for an industry as a whole because firms have opportunities to recruit (poach) from other employers. It is worth making a distinction between three pools of potential recruits, as strategies to recruit people from these pools are likely to be quite different. 1. Graduat es 2. Experienced staff 3. Retirees Possible response if there is a labour shortage This model suggests several possible responses to a labour shortage both: • Direct (increase inputs and decrease outputs) • Indirect (increase t he size of the pools that recruits can be attracted from). Direct responses:

• Increase graduate recruitment • Increase the recruitment of experienced people • Increase recruitment of retirees • Decrease res ignations

• Decrease retirements • Direct responses wil l usually be in competition with other industries. Indirect responses:

• Increase the number of graduates • Increase the pool of experienced people: - Increase leakage in - Increase skilled immigrants - Decrease leakage out • Increase the pool of retirees that would be willing to work. Indirect responses are likely to be more effective if they are undertaken cooperatively with other employers and industries. Competit ive responses to skills shortages by individual firms may result in perverse outcomes for the industry as a whole. Employers are more likely to try and attract staff by increasing the wages of new entrants than through a general wage increase. An example is a sign-on bonus. The consequences of being loyal to an employer may mean reduced wages relative to people with less experience who started more recently, and this in t urn increases the incentive to change jobs. High 'churn' means that employers are less likely to invest in training: why train someone who is going to leave? Reduced training then exacerbates the skills shortage.

technical features


G!]

refereed paper

water industry capacity development

Is There a Role for Government Intervention? Although it is clearly a key role of fi rms to find adequate employees, there are situations where government intervention is warranted to address skills shortages. Richardson (2007) classifies skills shortages in various levels with a level 1 shortage occurring when "there are few people who have the essential technical skills who are not using them and there is a long training time to deve:lop the skills". These types of shortage are difficult for firms or industries to address without broader support. Government intervention is also justified where increasing the number of people with skills that are in short supply will: • Increase the productivity of other works • Increase the employment of workers who have skills that are not in demand (these workers are likely to be experiencing high unemployment) • Provide essential services • Increase employment in a region that is economically disadvantaged. Many of the skills shortage issues currently being experienced by the water industry are likely to require government intervention. As noted by Richardson (2007): "the greatest policy and business concern should be for skills that have a long training period and where there is not already a good stock of suitably skilled people who are not using their skills to maximum effect". This suggests there is a clear role for government to increase the number of graduates where there are skills shortages.

Existing Activities Relating to Skills Shortages Ageing workforce/ skills shortages issues are well recognised by the water industry and government and there are a number of strategies in place.

Water Industry Capacity Development (WICD) The Water Industry Capacity Development program (WICD) is a collaborative initiative, headed by the Australian Water Association, that aims to address the long-term skills issues in the water sector. The three highest priority WICD projects are: 1. National Water Industry Employment Branding. Create a national brand to market the water industry/ sector and careers. The H2Oz careers in water campaign is now self sufficient with over 30 organisations subscribers and

Australian Government funding. See the H2Oz website: www.h2oz.com.au for more information.

There is a WICD website and water related organisations are invited to join http://www.wicd. org.au/ .

2. Water Industry Mentoring program. A structured approach to industry-wide mentoring to enable the transfer of knowledge to less-experienced water industry workers.

Water Industry Skills Taskforce (WISn

3. Intra Water Industry Secondments. A multidisciplinary approach to enhance water industry capability through structured workplace enhancement programs that provide opportunities to upgrade skills and knowledge of all staff. The online tool and support documentation is complete with launch scheduled for June 2010. A National Water Industry Skills Forum was held in Canberra on 17 March 2008 convened by the National Water Commission, Australian Water Association (AWA) and the Water Services Association of Australia (WSAA) as part of WICD. Outcomes include: • The industry will back a national awareness campaign to attract people into the water sector and promote the industry as a "sector of choice" . • To support career pathways in the industry, WSAA and AWA will spearhead an industry-wide exchange program to promote skills sharing. Incentives to attract skilled professionals will also be pursued through cadetship and fellowship schemes. • Recognising that the chronic shortage of maths, science and engineering graduates is impacting productivity across many industry sectors, the Forum supported Government incentives to boost enrolments in these courses. The industry will work with the education sector to increase the number of places in higher education programs. • In addition to these moves designed to tackle longer term skills and capacity building requirements, the industry also calls for short-term solutions such as more creative use of immigration arrangements to allow the water industry to target and attract skilled migrants. • To ensure these strategies are taken forward as part of an active plan for industry self-help, the Forum agreed to form a Water Industry Skills Taskforce. • A Water Industry Capacity Development Conference was held on 31 March 2008.

The Water Industry Skills Taskforce is chaired by Tom Mollenkopf (CEO AWA) and is made up of CEO-level representation from the water industry and related education and government sectors: AWA, WSAA, NWC, SA Water (Urban water utility representative), Veolia Water (consulting engineering organisation representative), GHD (Infrastructure/ Construction organisation representative), Government Skills Australia (Vocational sector), University of Melbourne (University sector), Irrigation Australian Limited and the Council of Australian Governments (CoAG) Working Group on Human Reso urces and Skills (ex officio) . The role of the taskforce is to promote and oversee a nationally coord inated effort to address the skills shortage in the water sector. The Water Industry Skills Taskforce has endorsed the three industry-led WICD initiatives.

Australian Government Initiatives On 7 December 2009, the Council of Australian Governments (COAG) agreed to 3 projects as part of a National Water Skills Strategy. These are part of the Raising National Water Standards program of the National Water Commission (DEWHA, 2009). • Up to $500,000 for a pilot program to trial development of training in water management skills for remote and indigenous communities • Up to $250,000 for the development of skills and training standards for operators of potable water treatment facilities • Funding on a 3-for-1 matching basis for up to $250,000 to support the H2Oz water industry marketing campaign and funding of up to $100,000 to enable the Australian Water Association on behalf of the Water Industry Skills Taskforce (and with support from the National Water Commission) to develop a business plan to implement the COAG National Water Skills Strategy. Additional initiatives by the National Water Commission include: • Funding the development of a Graduate course in water planning • A National Water Skills resource project to improve training in water management by developing consistent standards, resources for training, and consistent assessment.

water SEPTEMBER 2010 99


water industry capacity development • Setting up a National Centre for Groundwater Research and Training which is currently recruiting 120 higher degree students (http://www.groundwater.com.au/)

• Development of generic traini ng resources

• A fellowship program to fund training and research related to key areas of the National Water Initiative.

• Strategies to retai n mature age workers and manage and pass on their knowledge.

Water Education Network (WEN) The Water Education Network (WEN) has been developed by a partnership of the Australian Water Association (AWA) and the NSW Government Water for Life Program. A web-based searchable database contains information on educational resources related to the water industry http://resources.awa.asn.au/ .

Other initiatives There are specific programs aimed to retain water industry ski lls. For example, the South Australian government announced a program to retain 40 mature age workers in the state's water industry. This program, at a cost of about $200,000 aimed to retain mature workers as trainers, mentors and workplace assessors. In addition, large numbers of professional organisations are concerned about skills shortages such as the Institute of Public Works Engineering, Australia and the Institution of Engineers, Australia, Local Government, and the Planning Institute of Australia (Frost, 2009). There are also other federal government initiatives, for example, under the Commonwealth Government's Skilling Australia for the future initiative, the productivity places program will create 711,000 training places over 5 years in areas of skills shortages. Many of these will be relevant to t he water industry. The federal government has also agreed to support the Australian National Engineering Taskforce with $350,000 to fund two research projects related to the demand and supply of engineering skills and pathways for engineering education in the vocational education and training and university sectors (ANET, 2010). Other initiatives include: • Improvement of industry input into university courses and coordi nation and development of a range of opportunities for students to gain scholarships and industry experience. Improvement of graduat e literacy and communication skills 100 SEPTEMBER 2010

water

• Development of learning standards for industry courses and documentation of job profiles and industry skills sets

Skills Shortage and the Global Financial Crisis Recent reports suggest the skills shortages will continue even w ith the current global financial crisis: • There are still a large number of unfilled vacancies in Civil, Mechanical and Electrical Engineering and Environmental Sciences (AAGE, 2009) • A joint submission by engineering professional bodies and educators argues that any decrease in demand for engineers will be short term (APESM et al., 2009)

~

r e fereed pape r

• Higher staff turnover • Extra work that may be required to maintain the quality of products produced by inexperienced workers In addition, organisations are likely to have difficulty maintaining production because of a lack of workers. Issues around ageing workforces and skills shortages are well recognised by the water industry and there are strategies being developed by industry bodies including: 1. WICD - Water Industry Capacity Development program which is a collaborative indust ry initiative that aims to address the long term skills issues in the water sector. 2. Water Industry Skills Taskforce which aims to promote and oversee a nationally coordinated effort to address the skills shortage in the water sector.

• The gap between numbers of retirements and graduates means that there will be long-term issues around obtaining sufficient engineers (EA, 2008)

There are also initiatives by State and Federal governments but there is a clear need for government intervention to increase the number of University graduates in fields where there are skills shortages.

• The number of international students wanting to stay in Australia is likely to decrease as opportunities increase in their home countries (APESM et al., 2009)

These initiatives deserve the support of all participants in the water industry. Any relief in skills shortages because of the global financial crisis is likely to be short lived.

• Employer surveys suggest any job losses are being limited and employers are keen to hold onto their employees as a recovery is anticipated (Parker, 2009) • Long term demographic trends suggest there wi ll be labour shortages as the population ages (Costello, 2007; McDonald and Withers, 2008) • The unemployment rate peaked in Australia in November 2009 and has declined since • Skills shortages are seen as an increasing risk to business in 2010 compared to 2009 (Ernst & Young, 2010).

The Authors

Dr Tony Ladson is a senior hydrologist at SKM with more than 20 years experience in hydrology and river management. He has recent ly completed a book on Australian Hydrology for Oxford University Press. Email: arladson@skm.com.au

Conclusion There has been a series of reports over the last 5 years that have highlighted issues of ageing workforce/skills shortages. Ageing workforces and skills shortages lead to increased costs for business and government agencies including: • Higher wages • Increased costs of recruiting

Kate Austin is a Senior Associate and the Leader of Wat er Resource Modelling Practice at SKM, having reviewed the headworks models for Melbourne Sydney and Canberra.

References AAGE (Australian Association of Graduate Employers) (2009) AAGE Employer Survey. As cited in 'Career Matters' April/May 2009. Engineers, Australia.

technical features


refereed paper

water industry capacity development

ABS (2010) Average weekly earnings. Australian Bureau of Statistics publication 6302.0. February 2010. ANET (2010) Australian National Engineering Taskforce. http://www.anet.org.au/ see press release http://www.deewr.gov.au/ ministers/ gillard/media/releases/ pages/article_ 100330_ 142442.aspx APESMA (Association of Professional Engineers, Scientists and Managers, Australia; Engineers Australia; Association of Consulting Engineers Australia, and Australian College of Engineering Deans) (2009) Addressing market failure in undergraduate engineering: progress, opportunities and threats. Submission to the Deputy Prime Minister. April 2009. www.apesma.asn.au/newsviews/misc/ submissions/2009/market_failure_ undergraduate_engineering_apr_09.pdf Barrett, K. (2008) An assessment of the ski/ls shortage in the urban water industry. WSAA Occasional Paper No. 21. March 2008. Water Services Association of Australia. Booth, A. and Snower, D. (1996) Acquiring skills: market failures, their symptoms and policy responses. Cambridge University Press, Cambridge. Bozik, M. (2008) Mind the gap: pubic sector organisations are losing their ability to attract and retain the best technical professionals. Career Matters. Issue 9. Association of Professional Engineers, Scientists and Managers, Australia Costello, P. (2007) Intergenerational Report 2007. www.treasury.gov.au/igr Department of Employment and Workplace Relations (2005) Workforce tomorrow: adapting to a more diverse Australian labour market www.workplace.gov.au/workplace/ Publications/WorkforceTomorrow-Adapting toamorediverseA ustralianlabourmarket.htm Department o f the Environment, Water, Heritage and the Arts (2009) Water for the future: nat ional water skills strategy. Doughney, J. (2003). The Ageing Workforce? Separating fact from hype. Journal of Economic and Social Policy 10(2): 25-59. Engineers, Australia (2004) Submission to the Productivit y Commission on the Economic Implications of Ageing Australia. www. advanceaustraliafairly. com.au/pdfs/ BSL_ subm_ProdComm _econ _implicns_of _ageing.pd! Engineers, Australia (2008) Longterm trouble for the engineering sector confirmed, Media Release, June 26, 2008. Ernst & Young (2010) The top 1O risks for business. http://www.ey.com .au/ Publication/ vwLUAssets/ Business_Risk_Report_ 2010_PDF/$FILE/ B usinessRiskReport_2010.pdf Frost, S. (2009) The future floodplain risk manager: a portrait. 49th Floodplain M anagement Authorities Conference. Albury Wodonga http:// www. floodconference. com.au/asset s/ docs/Session%208% 20paper%2028%20Frost.pdf

ICEWaRM (International Centre of Excellence in Water Resources management) (2008) Gaps in skills, training and education in water management: a preliminary report. http://www.nwc.gov.au/ news/ski lls_forum/ Skills_Audit_Report_Oct_2005_ICEWaRM.pdf IAG (Independent Audit Group) (2009) Review of Cap Implementation 2007-2008. MurrayDarling Basin Authority, Canberra. Kaspura, A. (2008) The Engineering Profession, a statistical handbook. Institution of Engineers, Australia. King, R. (2008) Engineers for the future: addressing the supply and quality of Australian Engineering graduates for the 21st century. Australian Council of Engineering Deans. Ladson, A. R. and Austin, K. A. (2009a) On the floodplain manager skills shortage. Joint 49th Annual Floodplain Management Authorities Conference (NSW) & 6th Biennial Victorian Flood Conference. http://www. floodconference.com.au/assets/docs/Session % 208% 20paper% 2029%20Ladson.pdf Ladson, A. R. and Austin, K. A. (2009b) A skills shortage in the water industry. Hydrology and Water Resources Symposium. Newca st le 29 Nov - 3 Dec. Engineers Australia. http://www.h2009.org.au/. Leslie, G. (2008) Addressing the skills shortage in the urban water industry. Water Services Association of Australia. http://www.nwc. gov.au/news/ skills_forum/SkillsShortage.pdf McDonald, P. and Withers, G. (2008) Population and Australia's future lab our force. Occasional Paper 1/ 2008. Policy Paper #7. The Academy of Social Sciences in Australia, Canberra. McDonnell, A. (2009) Beyond 65 in the workforce - implications for death, disablement and income protection benefits. Mercer www .mercer.com.au/summary.htm?siteLangu age=1012&idContent=1343465. Murray, A. and Seddon, S. (2008) Preliminary water industry interaction with universities

survey. Water Industry Capacity Development. www. wicd .erg .au/ documents/ Uni_Courses_ Prelim_Survey_Results_FINAL.pdf Nathan, R. J. (2007) The f uture: a hydrological SWOT analysis. Australian Journal of Water Resources 11 (2): 133-144 Nat ional Farmer's Federation (undated) Summary of labour shortages in the agricultural sector. www.nff.org .au/ get/2449661872.doc OECD (2006) Country statistical profiles 2006 as cited in Costello, 2007 Palm Consulting Group (2008) National Water Skills Forum: Report on outcomes. 28 March 2008. www.awa.asn.au/ AM/Template.cfm? Section=Publications4&Template=/ CM/ ContentDisplay.cfm&ContentlD=9808 Parker, D. (2009) Workplaces look for smarter alternatives to slash and burn. Weekend Australian April 18-19. Professional p1 . New Cor poration. PC (Productivity Commission) (2004} Economic implications of an ageing Australia. Productivity Com mission Research Report. 24 March 2005 www.pc.gov.au/_data/assets/ pdf_file/ 0020/ 69401/ ageing.pdf Richardson, S. (2007) Water is a skills shortage? National Centre for Vocational Education Research. www.ncver.edu.au . ICEWARM (2008) National Water Skills Audit. International Centre of Excellence in Water Resources Management. Adelaide. Dep artment of Water Heritage and the Environment, Council of Australian Governments. Sturdy, J. (2009) Where are my staff when I need them? Journal of Australian Water Association 36(2): 6-8. Trendle, B. (2004) Perspectives on skill shortages. Labour Market Research Unit. Department of Employment and Training Queensland Government. http://www.trainandemploy. qld.gov.au/resources/ business_employers/ pdf/ wp33_perspectives_skill_shortages.pdf

C&S BRAND AUSTRALIAN FILTER COAL GRANULAR MEDIA FILTRATION FOR DESALINATION PRETREATMENT Reliable Quality and Service from a Company with more than 100 years of expertise in the manufacture of Coal and Carbon Products for Australian Industry

C&S BRAND GRANULAR & POWDERED ACTIVATED CARBONS JAMES CUMMING & SONS PTY LTD

I

319 Parramatta Rd, AUBURN NSW 2144 Phone: (02) 9748 2309 (02) 9648 4887 Fax: jamescumming @jamescumming.com.au Email: Website: www.jamescumming.com.au

Quality ISO 9001

............ Lie No. 1628

wat er

QUALITY ENDORSED COMPANY

AS/NZS ISO 9001 SAi GLOBAL

SEPTEMBER 2010 101


ITT TECHNOLOGY AT WORLD'S LARGEST UV FACILITY

w ter business

With a capacity to treat up to 1.8 billion litres a day of water, the largest UV disinfection facility for drinking water in the world to date - the SeymourCapilano Filtration Plant in Vancouver, British Columbia, Canada - celebrated its opening in May.

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.

The state-of-the-art plant actually became fully operational in January, but the celebration was put off due to preparations for the 2010 Winter Olympics held in the Vancouver area in February.

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.

The plant is equipped with 24 WEDECO K 143 Series ultraviolet (UV) light disinfection reactors from ITT Corporation, said Hui "Arthur" Ouyang, the company's western district manager for Canada. Located in the Greater Vancouver Regional District (GVRD) of British Columbia, it draws its water from the Seymour and Capilano reservoirs. Along with the Coquitlam Reservoir - all fed by namesake mountain watersheds north of Vancouver - they supply water for two million residents in the region. About 70 per cent of the area's drinking water needs are met by the Seymour and Capilano wat ersheds. "The 24 low pressure, high intensity lamp UV reactors are configured with one reactor after one filter. Each reactor has a capacity of about 20 million gallons per day (MGD). Every reactor has exactly 48 lamps in four rows of 12, with additional space for a fifth row for future expansion," Ouyang said . ITT, a global leader in the treatment and transport of water and wast ewater, was chosen in late 2004 to introduce UV disinfection technology to the plant based largely on a much lower lifecycle cost of the WEDECO system over competing brands. This included operation and maintenance as well as energy efficiency savings. The WEDECO system uses approximately two-thirds less energy than comparable medium pressure UV systems.

Validated according to U.S. Environmental Protection Agency guidelines, the WEDECO K Series of UV reactors are for large flow drinking water applications. The WEDECO SpektrothermÂŽ lamps are powered by the latest electronic ballast technology designed specifically for this lamp and controlled by a highly selective calibrated UV intensity sensor that allows for significantly lower energy costs. It also decreases the overall chemical use in drinking water. Among guests at the opening festivities were Metro Vancouver directors, staff, contractors, environmental groups, involved residents and local media. Lois Jackson, board director and chairwoman, led the toast with a glass of pure, mountain fresh water. The WED ECO success story began in 1976 with the formation of WEDECO GmbH and establishment of its first small production facilities in Herford, Germany. From the beginning, the company's business policy was shaped by the vision of chemical-free and environmentally friendly water treatment. Specialising initially in ultraviolet light disinfection processes, it branched into ozone oxidation technologies in the late 1980s, expanding internally and via acquisition through the years. In 2004, the company was acquired by ITT and, with the later reorganisation of the brand structure of

WaterGEMSÂŽ

ITT Fluid Tech nologies, was incorporated under the ITT Water & Wastewater umbrella. ITT Water & Wastewater is a global provider of water handling and treatment solutions for municipal and industrial customers in more than 140 countries. ITT designs and delivers energy-efficient solutions and related services for water and wastewater transport, biological treatment, filtration and disinfection. The company employs nearly 5,000 people through its global sales network, manufacturing sites in Europe, Asia and the Americas, and global headquarters in Stockholm, Sweden. ITT Water & Wast ewater is a business of ITT Corporation, a high-technology engineering and manufacturing company operating in three vital markets: water and fl uids management, global defence and security, and motion and flow control.

www.ittwww.com

BASIC WATER TESTING M ADE EASY The Eutech Economy range offers the greatest value for money of any basic handheld meters on the market today. Available in a range of parameters including pH , ORP, Conductivity, TDS, Salinity and Dissolved Oxygen, these economical handhelds are perfect for your basic water testing needs. Rugged and user friendly, all meters are built with shock-resistant ABS plastic and an IP54-rated housing protects against accidental splashing. They are also supplied with protective rubber boots that incorporate a hinge wh ich conveniently doubles up as a bench top stand - great for both lab and field applications. Other features include large easy to read LCD display, tactile keypad with simple design for easy operation, hold function which freezes screen momentarily for easy viewing and recording, energy saving auto-off after 20 minutes of inactivity, automatic temperature compensation and a

~ ~~D..!.!~Y

BRINGING TOGETHER ADVANCED WATER DISTRIBUTION MODELLING AND EASE OF USE Water GEMS comes equipped with everything engineers need in a flexible multi-platform environment, from automated fire flow and water quality simulations, to criticality and energy cost analysis, to flushing and water loss analysis. WaterGEMS can be run in ArcGIS, AutoCAD, MicroStation or as a stand-alone application. For more information, see the inside front cover of the September issue of Water Jou rnal, visit www.bentley.com/AWA, e-mail sales.haestad @bentley.com, or call +61 (0)3 9699 8699. 102 SEPTEMBER 201 0 water

Profile for australianwater

Water Journal September 2010  

Water Journal September 2010