Water Journal December 2008

Volume 35 No 8

DECEMBER 2008 ·~

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JOURNAL OF THE AUSTRALIAN WATER ASSOCIATION

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entley WaterGEMS V8 XM Edition continues with Haestad Methods' tradition of pioneering research and innovation, advancing the water modelling technology standard once again.

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Journal of the AustraUao Water AssodaUoo ISSN 0310-0367

Volume 35 No 8 December 2008

contents REGULAR FEATURES From the AWA President

Water and the Human Condition

D Barnes 4 From the AWA Chief Executive Water Water Everywhere But Would You Drink a Drop? T Mollenkopf 5

My Point of View Crosscurrent Aquaphemera Industry News AWA News Events Calendar

Mentoring Future Leaders

S Murphy 6 10 R Knee 12 18

23 30

Mark Pascoe awarded the 2008 Medal for Management Innovation - see page 18

FEATURE REPORT Ecosystem Response Modelling in the Murray-Darling Basin

34

Understanding how the health of ecosystems across the Murray-Darling Basin respond to changes in water availability was the focus of a meeting of scientists and water managers from around the Basin.

I Overton New recycled water factory at Epsom opened - see page 20

AWA 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

'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. '

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 Edie Nyers, Editor, Water Journal - journal@awa.asn.au

PUBLISH DATES Water Journal is published eight times per year: February, March, May, June, August, September, November and December.

• Water Business and Product News Brian Rault, National Sales and Advertising Manager, Hallmark Editions - brian.rault@halledit.com.au

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

ADVERTISING Advertisements are included as an information service to readers and are reviewed before publication to ensure relevance to the water sector and objectives of the AWA. Brian Rault, National Sales and Advertising Manager, Hallmark Editions - brian.rault@halledit.com.au Tel: +61 3 8534 5014

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

AWA

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

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

The health of the Murray-Darling and the riverine ecosystems is at risk due to the current drought and the likelihood that decreased run-off will be maintained indefinitely. Researc hers are creating models to link ecological responses to changes in water flows. See page 34 for more.

water

DECEMBER 2008 1

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Journal of the Australian Water AssociaUon ISSN 0310-0367

Risk Management Review of the Rouse Hill Dual Reticulation Scheme see page 47

TECHNICAL FEATURES( ~

Volume 35 No 8 December 2008

contents

Impeller Selection for Wastewater Pumps - see page 74

INDICATES THE PAPER HAS BEEN REFEREED)

WATER REUSE

Reuse In Western Victoria Reviews from four regional authorities

Compiled by E A (Bob) Swinton

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GLanders, S McLeod

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J O'Toole, M Sinclair, K Leder

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18 Law

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Report by E A (Bob) Swinton

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R M Pashley, M J Francis, M Rzechowicz

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D Luketina, S Christie

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M Hadavi

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K Third, A Shaw, T Bridle, S Cooper

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Risk Management Review of the Rouse Hill Dual Reticulation Scheme Ongoing risk management for recycled water systems

[ii Recycled Water Exposure: Filling the Data Gaps Understanding the risk profile for non-potable uses

[ii The Future Direction for Potable Reuse Direct potable reuse may have lower environmental footprint than indirect potable reuse DESALINATION

DESALTING 2008 An excellent Specialist Conference Unusual Properties of Water: Effects on Desalination Processes These properties might assist in the development of improved and novel processes Monitoring of the Perth SWRO Brine Outfall No discernible effect on DO levels in the deeper basin WASTEWATER TREATMENT

Impeller Selection for Wastewater Pumps The cost of correcting unexpected blockages can be very high

[I] Accounting for Greenhouse Gas Emissions in Wastewater Treatment For truly sustainable design, look at the 'bigger picture' WATER BUSINESS

New Products and Business Information

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Advertisers' Index

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my point of view

Mentoring Future Leaders Sue Murphy Sue Murphy graduat ed from the University of Western Australia in civil engineering in 1979 and joined construction company Clough, risi ng from junior g raduate engineer to executive roles. She joined the Water Corporation in 2004 as General Manager, Planning and Infrastructure, and was recent ly appointed CEO t o replace J im Gill w ho officially st ands down at t he end of this year.

Managing a large organisation today is a more comp lex and demanding occupat ion than it has ever been before. In our business world of far greater scrutiny, transparency and accountability, t here are so many layers of critical tasks that need unrelenting attention. All of which places huge demands on those at t he helm.

These demands apply in any busin ess sector but are, I believe, at t heir peak in the business of water supply and wastewater co ll ection, treatment and d isposal where we are provid ing essential serv ices that have big influences o n our lifestyle, health and t he envi ronment.

Hand in hand with all this is t he growing need to ensure that good succession planning is in place so t hat future managers are fit for these tasks. This in turn cal ls for a healthy culture of mentoring of young people within an organisation if it is to achieve its goals.

I joined the Water Corporation four years ago as General Manager, Planning and Infrastructure, and soon encountered a big surprise. The Corporat ion covers an immense area in an extremely difficult environment, with an annual capital program of almost $1 bi llion and about $12 billion in infrastructure across the state. We supply drinking water to more than 250 cit ies and towns and operate more than 100 wastewater t reatment plants.

I t herefore expected t hat t he issues and areas w here our st aff would seek guidance, mentoring and support wo ul d be related to technical problems or t he details of wastewat er process or wat er treatment. However, the s urprise was that this was not t he case. Ou r younger people had more concerns related to the issues of leadership, managing a diverse workforce and how to inspire and motivate others.

Sharing our experience The challenge for me - and for every sen ior manager - is to pass on to our younger colleagues t he good and the bad we have experienced in a way t hat shows we have faith in them, so t hat they can grow and learn without having to make every mistake t hemselves. Mentoring is a great way to do this, and t here is a bonus in that the learning is a two-way street, with younger engineers helping me to see a better way to do many things myself.

How we deal with each other, show respect for others, share our passions for the roles we have are w hat define us - not our job title!

6 DECEMBER 2008 water

I encount ered some excellent examples of how effective this kind of mentoring can be in the formative years of my own career.

I graduated from t he University of Western Aust ralia in civil engineering in 1979 and joined construction company Clough t he following year. I had been awarded a Clough Scholarship in my final year of university and accepted their job offer w ithout really consideri ng that construction may not be an ideal environment for a youn g woman.

In fact, I can remem ber being far more st ressed about what to wear - jeans and st eel caps or a business su it - t han about the act ual role. Sheer naivety probably gave me far more confidence than common sense wou ld dictate, and I proceeded t o have a wonderful time on site and in project offices.

In those days the yo ung male graduates were considered "fair game" by the older supervisors who delighted in bringing them down a peg or two. But I found that some inherent chivalry in t hese hugely knowledgeable foremen gave me a small window in which to prove myself . I was interested in their practical ski lls and expertise and learned an enorm ous amount from t hem .

Man-management skills But my real gain was in watch ing their man-management skills .

Leadership in an organisation can be allocated by t itle, but in the field it must be earned, and these men were experts at t his.

When they gave me their trust, it opened the doors in ways I could never have expected. Their opin ions were highly valued so their approval was somethi ng I am proud of to this day.

Over t he years t here were many times when projects were not going well and I would share with Harold Clough my concerns . He would just say: "You smart young people always seem to come up wit h great solutions." Even though it was his company and his mo ney, he seemed to have faith that we could sort t hings out. So we worked ludicrously hard to make sure we did just t hat.

Having people have faith in you is both empowering and terrifying - a perfect atmosphere for delivering you r best!

For more information on the new industry-wide mentoring program see page 8.

crosscurrent

National

Seven new 'adaptation research networks' will foster critical research into the effects of climate change.

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The National Water Commi ssion has rel eased its 2007-08 Annual Report, with CEO Ken Matthews stating that national water reform is more vital and urgent than ever. The report also raises alarm over the overuse and pollution of the nation's groundwater supply which now makes up 30 per cent of the country 's water consumption.

The Commission has also released a report showing that desalination technologies will play an increasingly important role in securing Australia's water supplies. "Emerging Trends in Desalin ation" aims to inform decisions on the merits of desalination technologies and thei r future plac e among water supply options. Both reports c an be downloaded from th e NWC website www. nwc.gov.au

The Commonwealth Government has released the "Australia's Low Pollution Future" Report, which contains Treasury's modelling of the costs and opportunities of responding to climate change. A summary of the report, along with the full Report, are available at www .treasury.gov.au/ lowpollutionfuture/

The Rudd Government will provide $10 million over four years to establish research networks investigating the effects of climate change on areas such as water resources, human health , emergency services, infrastructure and biodiversity.

AV-IA

Conference Format

Keynote Speakers

A t hree day conferen ce and exhibiti on featur ing

Dr D avid Furukawa

oral presentations, a pos ter session, an evening workshop and concluding plenary

A new Industry Report titled " Leadership in Sustainable Urban Wat er Management: An Investigation of the Champion Phenomenon within Australian Water Agencies" has been released as part of the National Urban Water Governance Program (NUWGP), which comprises a group of social research projects investigating the changing governance of urban water management in Australia. The Program is intended to facilitat e progress towards achieving a Water Sensitive City by drawing from a number of social theories concerning institutional and technologic al change processes. www.urbanwatergovernance.com/

The Murray-Darling Basin Commission and the Bureau of Meteorology have stated that there is no prospect of recovery of the Murray Darling river syst em this year due to poor spring rains.

Lower Lakes communities at the mouth of the Murray River can look forward to a more secure drinking water supply early in the New Year now that construction has commenced on 130 kilometres of pipeline in the region. The pipeline is being built in response to critical drought conditions facing the communities of the Lower Lakes and to the deterioration in the cond ition of the lakes.

National water broker Waterfind released their 2007-08 Annual Water Market Report. Prices for temporary irrigation water licenses have tumbled 50 per cent to $400/ML in the first quarter of 2008-09 compared to a price of $800/ ML at the same time last year and is well below the record high of $1200/ ML in November 2007.

The Green Precincts Fund was announced in the 2008-09 Budget with funding of $15 million over four years to support 10 plus high-profile demonstration projects that must deliver water and energy efficiency savings while at the same time educating the community about water and energy efficiency.

Separation Consu ltants

Californ ia, USA

Pre · Confereoceiour Dr Kerry Schott Managing Director Sydney Water.Australia

A pre-conference tour to Sydney W ater 's Industrial water reclamat ion facility at Bluescope Steel's plant south of Syd ney will be held on Tuesday IO February 2009

Australian Capital Territory •

Y.e.n.u.e Stamford Plaza Hotel. Oouble Bay. Sydney

D r G raem e Pearce Membrane Consutuncy

Wednesday I I February 2009 until

Inc. UK

ACTEW reminded Canberra residents that mandatory water restrictions are in place, after the ACT exceeded its daily water consumption target every day in the last week.

Friday 13 February 2009

Conference Topics • N ew Membrane Technology

Beeistration from S87Q

• Water Reclamation and Desalination • Membrane Bioreactors • Cost Co ntainmentS, Energy Use and Impacts

for J ~day conference including dinner and evening workshop

New South Wales

Further Information Who Should Attend • • • •

Water t reatment specialists Dcsaltcrs Water uti lity operators Environmental scicntisu and engineers

Full conference program, registration onlinc and furt he r information c1.vailablc at the conference website

~ Phone: Fax: Email:

(02) H36 0055 (0 2) 9436 01 55 evcnu@awa..1sn.au

www.awa.asn.au/events/mdsc3

10 DECEMBER 2008 water

The pumping of water from the Shoalhaven River to top up dam supplies for Sydney will be arrested for at least three years because levels of wat er in the system (at 65.1 %) have been deemed sufficient for the time being.

The first wi nd turbines of a total of 67 were installed at Capital Wind Farm at Bungendore. Their energy will offset

crosscurrent power use for Sydney's desalination plant and boost supply of , wind energy in NSW by more than 700 per cent.

During National Water Week, the Acting Compliance Director for NSW Department of Water & Energy drew attention to water theft and encouraged members of regional communities to report offenders. Fines for water theft could soon increase to up to $1.1 million for an individual and up to $2.2 million for a corporation.

farmers understand their crops' water needs, with preliminary findi ngs indicat ing a strong correlation between the way in which a crop is managed and the ability of the crop to withstand stress.

River Murray irrigation allocation to SA was increased from 11 % to 15% due to a slight improvement in water availabi lity from additional inflows into the River Murray system during September, with good rainfall late lead to a total of 400 GL of inflows.

Solar-powered water churners, costi ng $500,000, are being trialled in Sydney's Warragamba Dam to reduce the risk of a repeat of the last summer's toxic blue green algae outbreak.

Regular water quality t ests monitoring will reveal the success of the devices.

Queensland The debate about the Queensland government decision to pump 60ML of purified recycled water into Wivenhoe Dam was reignited, with commentators stating that the technology is not infallible and carries risks . Major support for the project has been provided by Queensland Water Commission which has endorsed the strategy and provided data to support the safety and quality of purified recycled water.

The QLD Sustainability, Climate Change and Innovation Minister released results of an investigation into dead mangroves on the Fitzroy River, with chem icals ruled out as the cause. The EPA concluded that the die-back was a result of t he major flooding that occurred in January and February 2008.

Toowoomba will become the first large urban centre to draw its town water from t he Great Artesian Basin, with more than 400MUmonth to be extracted t o meet the needs of t he drought-ravaged city. A $17 million project is under way to drill bores to meet Toowoomba's requirements.

The Sunshine Coast Environment Council called on the State Government to ensure that the Northern lnterconnector Pipeline is equipped with a 2-way flow to deliver water back to this region in times of need and when Brisbane 's supply is adequate. The group also says developers need to be made more account able to protect local waterways in the region.

A research team at the University of Queensland says it is ready for a large-scale trial of a process that uses sunlight to purify water. Photocatalysts and visible light can be shown to efficient ly break down the pollutants in wastewater from industry.

South Australia The SA State Government has invested more than $1 million in t hree projects through its Drought Response Program to help

12 DECEMBER 2008

water

Tasmania • The Board members for the new Tasman ian Water and Sewerage Regional Corporations were announced, with Geoff Willis as the Common Chair heading up the Boards. These will consist of three other directors common to each board and two directors specific to each regional corporation. Geoff Willis, Dan Norton, Miles Hampton and Brian Bayley will fi ll the Common Director roles. The Regional Directors are Sarah

AQUAPHEMERA With the Greens holding the balance of power in the new ACT Assembly, t heir agreement with the ALP to hold power (www.act.greens.org.au/documents/alp-greens-agreement. pdf) includes t he followi ng water policies: • plumber visits to Government houses and low income earners to implement water efficiency measures; • a water inquiry t o ensure a sust ainable water supply; • replacing stormwater drains with urban creeks and wetlands; and • inclusion of a third pipeline for non-potable water in the new Molonglo development.

Interestingly, in the letters to the editor in the Canberra Times , more people are now questioning the logic of some of t hese measures. For example recog nising that in an inland city, any wat er use, whether it be recycled or not, is reducing flows downstream; and the significant cost of recycling and rainwater tanks both in dollar terms and energy. That is not to say they are not necessarily good options, just that they should be measured by triple bottom line objectives, not dogma. For example, recycling can be directly compared to the new potable water sources, desalination, dams, etc in terms of life cycle cost including carbon offsets, the impact on the total water cycle, and the risks in terms of t he environment and health.

The Greens would do well t o read Water Recycling in Australia from Horticulture Australia Ltd, Land and Water Aust ralia, and others (www.reclaimedwater.com.au/ uploads/File/Water%20Recycling_in_Australia.pdf).

This succinctly sets out in an easy to read document (with a glossary), the benefits of recycling, why we need to do it, treatment processes; and risk management. The latter covers potential risks including environmental and health for agriculture and around the home. It also raises that we need to resolve who owns recycled water and how much is it worth.

- Ross Knee

While 70 per cent of the world's surface is covered by water, only one per cent of the total water resources on earth is available for human use.

crosscurrent Merridew and Liz Swain (Northern Water and Sewerage Corp), Tony Maccormack and Grant Atkins (North Western Water and Sewerage Corp), and Roger Gill and Rob Woolley (Southern Water and Sewerage Corp).

Submissions have been sought for the Tasmanian Water Quality Policy Review 2008. The policy applies to ambient water quality and does not cover water quantity and allocations, or management of drinking-water quality.

Government unless their home state has agreed to Commonwealth demands over abolishing certain trading rules.

Victoria currently retains a series of barriers to water trading. http://www.environment.gov.au/ minister/ wong/2008/ mr20081102.html

The $47 million Epsom-Spring Gully Water Recycl ing Project has been completed, supplying the city of Bendigo with an additional 4,000 ML. The recycled water wi ll provide extra water for rural irrigation and for watering urban venues such as sporting venues and parks.

Victoria Melbourne's water authorities are investing more than $5 billion in major projects over the next four years to boost water supplies, increase the use of recycled water and reduce leaks and bursts from the system. The Water Plans for each water authority are available online at www.esc.vic.gov.au

Prices for water in Victoria are expected to rise significantly following receipt by the price regulator of likely costs and returns for 2009-2010 from major metropolitan utilities servicing the state.

Small scale farmers seeking financial incentives to quit irrigating will be unable to receive money from the Federal

EPA Victoria is reviewing the framework and guidance for managing the use of recycled water for schemes greater than 5000Uday. Forums were held throughout November to understand stakeholder perspectives of what works, what doesn't work, the gaps, the barriers, conflicting information, and information that requires further clarity in the relevant guidance documents.

Western Australia

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The Department of Health warned people to avoid contact with an algal bloom in the Serpentine River, which extended from the Peel Inlet to Ibis Retreat, Stakehill. The algae caused a green discoloration and surface scum in the water and contact

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regula

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Pumps• Valves• Systems

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Th is does not change wi th KSB. The heart of the newly-developed Ama rex KRT waste water pump is the closed jacket cooling system of the motor. Th is re liable cooling method and the simple, modular motor design does not only increase the operating re lia bility bu t also considerabl y enhances efficiency and maintenance friendlin ess.

Econom ical, powerfu l, an d environmenta lly friendly: Ama rex KRT is t he ideal so lution for all tasks in municipa l and industrial waste water engineerin g.

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industry news Management Innovation Recognition Mark Pascoe, CEO of the International WaterCentre, has been awarded the 2008 Medal for Management Innovation by the Australian Institute of Management. The Medal was awarded at the Management Excellence Awards in November in Brisbane.

The annual Management Excellence Awards recognise managers who lead and inspire Australian business and turn belief and passion into viable, sust ainable businesses.

In the 30 years that Mark has dedicated to the water industry, he has worked in management roles at the Brisbane City Council, Woodward-Clyde Pty Ltd, International Water Association in London and is now leading the International WaterCentre in Brisbane. The International Wat erCentre undertakes education, training, research and consulting and is a joint venture of The University of Queensland, Griffith University , Monash University and The University of Western Australia.

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Mark Pascoe FAIM, Chief Executive Officer, International Water Centre, was the recipient of the 2008 Fisher & Paykel Medal for Management Innovation.

Mapping Australia's Renewable Energy Resources The first user-friendly interactive atlas to map the full extent of Australia's renewable energy resources has been launched recently.

The on-line Renewable Energy Atlas is available to organisations and the public who want s to know more about Australia's energy potential and the array of options available. It is expected to be used by planners and investors to expand and develop renewable industries in Australia, as well as helping build community awareness of potential for growth in the area.

Designer and manufacturer of high efficiency, low speed floating and fixed surface aerators from 3kW to 220 kW w ith an unmatched 5 year, unlimited hours g uarantee.

By-Jas offers flexible financing and delivery sol utions including rental, purchase and fully maintained operating leases. Ring now for a current stock list. Other products in our range include settling ta nks ( 12 designs), packaged sewage and water treatment plants, reuse filters and clarifiers to Class Band Class A standard .

For more information, contact: By-Jas Engineering Pty Ltd PO BOX 424, HASTINGS VIC 3915 Tel: (03) 5979 1096 Fax: (03) 5979 1524

18 DECEMBER 2008 water

The atlas shows in-depth, nationwide information on all forms of renewable energy, with solar exposure, wind speeds, wave and tidal data, biomass and geothermal temperatures all charted in the resource. Other information includes contours, roads, towns, electricity transmission lines and climatic factors, which provide context for the data.

Funded under the Australian Government's Low Emissions Technology and Abatement Program, the Renewable Energy Atlas will continue to be developed over time.

To explore the Renewable Energy Atlas visit www.environment.gov. au/renewable/atlas

industry news New Water Recycling Factory for Bendigo The Bendigo region will use up to four billion litres of recycled water every year from the new Recycled Water Factory at Epsom which was officially opened last month.

The new factory marks the completion of the $47 million Epsom-Spring Gully Water Recycling Project, which was built over t he past two years to give Bendigo even greater confidence about its future water security.

The Recycled Water Factory will recycle all Bendigo's wastewater and is a key part of diversifying Bendigo's water sources and developing a secure supply for the region, one of Australia's largest inland cities.

The Victorian Government provided $6.55 million towards the Epsom to Spring Gully Recycled Water Project and a further $6.3 million came from the Commonwealth Government's Water Smart Australia Program.

Coliban Water has offered Class A recycled water to 350 rural customers along its Ascot, Axe Creek and Cockatoo Hill channels. Recycled water will also be used to sustain Rosalind Park, Queen Elizabeth Oval, Bendigo Tennis Courts, Tom Flood Sports Centre, White Hills Botanical Gardens, Bendigo Golf Club, Bendigo Jockey Club and the Bendigo Harness Raci ng Club.

$10 Million for Climate Change Research Networks The Federal Government will provide $10 milli on over four years to establish research networks investigating the effects of climate change on areas including water resources, human health, emergency services, infrastructure and biodiversity.

The seven new 'adaptation research networks' wi ll fost er critical research into the effects of climate change. The research networks, for t he priority sectors have been allocated as follows: • Water resources and freshwater biodiversity - Griffith University • Terrestrial Biodiversity - James Cook University • Marine biodiversity and resources - University of Tasmania • Disast er management and emergency services - AMIT University • Settlements and infrast ructure - University of New South Wales • Social, economic and institutional d imensions - Melbourne University

The Hon. Minister Tim Holding, The Hon. Steve Gibbons, The Hon. Jacinta Allen and Caliban Water Chairman John Brooke taking a tour around the new Recycled Water Factory.

The Recycled Water Factory uses ultra-filtrat ion and reverse osmosis to remove salt from Bendigo's disinfected wastewater and safely disposes of the brine by EDA concentration followed by lagoon evaporation.

Carbon Pollution Reduction Scheme is a critical focus of the Federal Government's approach to climate change, t he country also needs to be prepared to adapt to changes in the climate that can't be avoided. "Taking action now to reduce the future impact of climate change on our communities, environment and industries is a critical pillar of our strategy," said Minister Wong.

The networks are set to bring together some of the best brains in Australia supported by more than 20 partner research institutions from across the country to advance our understanding of how specific sect ors and reg ions will be affected by climate change and what action is needed to reduce the risks.

Griffith University welcomed the announcement that it wi ll host the Water Resources and Freshwater Biodiversity network of the National Climate Change Adaptation Research Facility, which wi ll be co-located with NCCARF's national headquarters at Griffith. The network will also benefit from being collocated with Griffith's three flagship water research centres; the Australian Rivers Institute; the national Tropical Rivers and Coastal Knowledge research program's Queensland hub, and the Queensland Government's Smart Water Research Facility.

• Human Health - Australian National University All seven networks will be administered by the National Climate Change Adaptation Facility (NCCARF) based at Griffith University, Queensland.

Minister for Climate Change and Water, the Hon. Penny Wong stated that while reducing emissions through the

20 DECEMBER 2008

water

Australian Rivers Institute Director and newly-appointed National Water Commissioner Professor St uart Bunn will lead the network at Griffith, with activities coordinated around four key adaptation themes: Water allocation, markets and trading; water reso urces; biodiversity and ecosystem health; and climate scenarios.

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industry news Early Action Makes Cents The Treasurer and the Minister for Climate Change and Water released Australia's Low Pollution Future: The Economics of Climate Change Mitigation in October 2008, and according to the Ministers, the modelling demonstrates that early global action is less expensive than later action.

The report also argues that a market-based approach allows robust economic growth into the future even as emissions fall; and that many of Australia's industries will maintain or improve

Upgrade Homes to Downgrade Consumption Victoria's peak building industry body, the Master Builders Association, has called on the State Government to mandate the installation of low-flow showerheads and dual-flush toilets as a pre-sale condition for all Victorian homes.

Master Builders Executive Director, Brian Welch , said due to poor spring rainfall, an urgent rethink of Government attitudes toward minimum water consumption standards in existing homes is required.

"With Stage 4 Water Restrictions being flagged as a potential consequence of poor 2008 rainfall , it would be a shame to penalise the entire Victorian public when so many households are still not doing the bare minimum when it comes to water consumption efficiency," Mr Welch said.

In its submission to the State Government's Inquiry into Melbourne's Future Water Supply, the Association stated that an average of 65,000 litres of water was wasted each year per household by inefficient showers and toilets.

"At present, there are over 589,000 homes which still do not have low-flow shower heads and almost 230,000 homes which do not operate dual-flush toilets ," said Mr Welch.* According to the Association, Victorian homes change hands every seven years, so these measures can flow through the community relatively quickly and at minimum cost.

their competitiveness under an international agreement to combat climate change. According to the findings, even ambitious goals have limited impact on national and global economic growth.

Real household income will continue to grow, however households will face increased prices for emission-intensive products, such as electricity and gas.

The full report and summary of findings are available online at www.treasury.gov.au/lowpollutionfuturel

Water Savings: Toilets: • 230,000 homes have single flush toilets • Dual-flush toilets use 3 to 4.5 litres per flush, compared with 11 to 13 litres with single-flush • With dual-flush conversion, potential annual water saving of 35,000 litres per household • Total potential water savings: 230,000 homes x 35,000 litres = 8.05 billion litre saving • Cost: $200-$1000 per unit

Showerheads: • 589,000 homes have inefficient showerheads • Low-flow shower heads use 9 litres of water per minute, versus 20 litres per minute for inefficient showerheads • With showerhead conversion, potential annual water saving of 30,000 litres per year per household • Total potential water savings: 589,000 homes x 30,000 litres = 17 .6 billion litre saving • Cost: $30-$200 per unit * Vic State Government's 2008 Green Light Report

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NSW

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ACT A.Jackson

Arch International Pty Ltd PO Box 519 North Sydney NSW 2059 Telephone: 02-99006104 Fax: 02-99545467

NSW G.Ahamat, S.Balu, C.Barton, N.Esber, C.Goodall, P.Miller, A.Rahardjo, G.Rossington, G.Scott, A.Sharp, O.Torkel

Ve olia Water Network Services Level 2, Suite 210 29-31 Lexington Drive Bella Vista NSW 2153 Telephone: 02-9839-2100 Fax: 02-9839-2199

NT N.Green

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4 Vera Street Helensburgh NSW 2508 Telephone: 02-4294-2779 Fax: 02-4294-2779 Umwelt (Australia) Pty Ltd

PO Box 838 Toronto NSW 2283 Telephone: 02-4950-5322 Fax: 02-4950-5737 SA

Corporate Bronze Environmental Water Services (EWS) PO Box 53 Hahndorf SA 5245 Telephone: 08-8388-5644 Fax: 08-8388-5645 VIC Corp orate Bronze ITT Fluid Technology International (Australia) Pty Ltd Unit 3 , 1 Federation Way Chifley Business Park, Mentone VIC 3194 Telephone: 03-9551-7333 Fax: 03-9551-0321 Klohn Crippen Berger Ltd Level 1, 89 High Street Kew VIC 3101 Telephone: 07-3004-0244 Fax: 07-3004-0299 WA Corporate Bronze Re Pipe Pty Ltd

44 Roxburghe Drive The Vines WA 6069 Telephone: 08-9297-4824 Fax: 08-9297-4825 Corporate Silve r OptaMAX Pty Ltd PO Box 20 Karrinyup WA 6921

QLD G.Child, A.Hoban, D.Mclnnes, C.Moir, B.Phillips, K.Rabaey, L.Szep SA L.Mosley, A.Rossi VIC K.Assi, B.Bayliss, P.Cameron, L.Cini, J.Holt, B.Jensen, L.Leong, P.Perez-Reigosa, D.Stevens WA H.Aljrood, M.Black, L.Bluxton, A.Boldero, J.Chan, J.Clasby, L.Cummins, F.Kercheval, M.Ludwig, U.Moothoosamy, S.Pan, J.Pickford, P.Pitchen, P.Seares, T.Stewart, M.Tay, E.Thompson, D.Westwater, Y.Yu, C.Zammit Overseas A.Arscott, M.Gibb

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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.

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John Morris Scientific Service plus Solutions

awa news Australasian Biosolids Partnership The Australian Biosolids Partnership (ABP), formed in early 2008, is now hitting its stride with several important initiatives underway or in place. The ABP promotes and supports the sustainable management of biosolids. It currently has 33 members Australia-wide and in New Zealand.

An important development is the launch of the AB P websites at www.biosolids.com.au . These websites - one for ABP subscribers and the other for the general public - are repositories of information regarding biosolids management and resources t o the industry and the community generally.

Over time, the information on the site wi ll become increasingly comprehensive, with information available on biosolids management generally, developing trends, case studies, new research and resources to support effect ive community education and consultation.

biosolids. Dr Geoff Syme of Edith Cowan University in Western Australia is assisting in the planning and design of this survey which w ill likely be conducted early in the 2009.

An additional area of research interest will be an analysis of the efficacy of legislation, regulation and guidelines that affect the management of biosolids, and the extent to which these represent world's best practice. Currently, there is significant variation in the regulation of biosolids among the Aust ralian States and Territories, federally in Australia and in New Zealand. The analysis to be carried out by the ABP will provide a basis for suggesting changes to requirements in Austral ia in New Zealand to promote consistency and to ensure that world's best practice in regulation is pursued.

All of the above wi ll feed into the overall comm unications strat egy to be developed as part of the ABP 's initiatives.

A second important initiative wi ll be a survey of community attitudes. This research will provide insight into the views held by the community generally, specifically affected communities and users of biosolids, to the use and management of

Further information is available from Andrew Speers or Ann Hinchliffe at the National Office of the Australian Water Association.

IWA-ASPIRE

Pacific Water Sustainability'. Abstract submission deadline is 31 December 2008.

Following successful !WA-ASPIRE conferences in Singapore (2005) and Perth (2007) the 3rd Conference will be held in Taipei (18 -22 October 2009) with the theme 'Working for Asia-

Professional Development Courses

2009 In a slowing economy, more people are looking at how they can secure their job, improve their technical knowledge and perhaps gain that winning edge t hat is so valuable to business success. AWA has developed some new opportunities to assist members seeking to upgrade their skills and learn more about new technologies Master Classes: First off the blocks wi ll be AWA's May 2009 Master Class on Project Management with a focus on water infrastructure projects. Key speakers wil l bring a mix of theory and practical experience on recent water projects to share with the class. They include David Fligelman (Tyr Group), Dale Cooper (Broadleaf Capital), Michael Tuckfield (Clayton Utz) and Graham Dooley (Osmoflo).

Mast er Classes are generally small in number - a maximum of 25 attendees - with the goal of encouraging discussion among participants about the issues and case studies presented. Networking and learning from one another is equally as important as the information covered in the formal t eaching mode. The Classes ru n over two days and are held in Sydney. For an outline of the program, price structure and the opportunity to Register, please go to http://www.awa.asn.au/events/mc09

24 DECEMBER 2008 water

More information and program can be found at http://www.aspire 2009. org.

The second Master Class in 2009 will be held mid- August and the subject wil l be Water and The Law . The program for that Class will look at some of the recent commonwealth and state based legislation that impacts on the water industry.

Registration for the class wi ll begin early April 2009.

AWA Membranes and Desalination Specialty Ill Conference wi ll be held February 11-13th are the days to mark in your calendar. The conference has been co-badged with the 2n d Asia Pacific Desalination Association Conference, a grouping of regional associations who are interested in developing, using and learning more about desalination technologies in planning for management of their water resources.

Key international speakers for the event include David Furukawa, a highly respected membrane researcher who is recognised for his work on low pressure membranes.

Pretreatment specialist, Graeme Pearce from Membrane Consultancy Ltd in UK is also speaking. There is a very ful l program of presentations covering all aspects of membrane development, application and troubleshooting. Desalination, membrane bioreactor systems, plus issues of cost management and energy use mitigation are among topics to be addressed. A Poster session and up to 10 trade booths are planned. Details and registration at http://www. awa.asn. au/events/mdsc3

awa news • The need to redraft the Terms of Reference to include changes that better reflect AWA's expectations of Specialist Networks and the support AWA will provide.

• The need for further development of online tools (forums, webinars etc) to provide more opportunities to engage members and provide benefit • To make better use of communications opportunities (e.g. increasing the presence of Specialist Network related articles and information in Water Journal) • To provide members with more opportunities for active participation through establishment of the 'Community of Experts'.

As part of that process, in August 2008, AWA called for members to nominate themselves for a position on any of the 16 Specialist Networks (excluding Young Water Professionals' committees). There was a great response to this call and even more exciting was the number of people coming forward who had previously not been actively involved in AWA activities in th is way. Many of the committees were oversubscribed and some difficult decisions had to be made to select a committee which had a good balance of people from around the country and from the different fields involved in each specialist area.

With the committees and their co-conveners in place, the next step was to hold the 1st National Conveners meeting wh ich took place on 25 November. The meeting involved

around 40 people including co-conveners from all the Specialist Networks, as well as Branch Presidents and several members of AWA's Board of Directors. The meeting provided an opportunity for conveners to be introduced to the relevant staff and volunteers within AWA, to be briefed on current AWA policies and procedures and support provided to Specialist Networks, and to workshop ideas on how Specialist Networks may facilitate activities that contribute to achieving AWA's strategic objectives. As the meeting also involved AWA Branch President s and some AWA Board members, it provided the conveners with an opportunity to gain an insight into the inner workings of AWA, both at a strategic level, and more locally around the country.

We had a very productive day which generated some great ideas for how the networks will progress towards achieving the goals each individual network will be setting, and providing greater benefits for AWA members. A report on the day's outcomes will be available shortly and wi ll assist each network in making their plans of action for the coming year.

So with many exciting developments on the horizon and lots of work to keep us all busy, 2009 already looks like it will be an action-packed year. I hope you all find a bit of time over the holiday period to relax and reflect on all we've achieved this year. I'd like to thank all of you who have volunteered, or contributed your time in some way, to make the networks a success. See you all in 2009!

Event Calendar AWA and Affiliated Events Now is the perfect time to mark some of the important industry events coming up in 2009.

For more information, visit www.awa.asn.au/events Date

Event

Contact

Friday 12 Dec 2008

YWP - Technical Meeting/ End of Year Networking North Adelaide SA Australia

Alison Bowman 08-8359-3242

Wednesday 17 Dec 2008

NSW Branch Committee Meeting Sydney NSW Australia

Despina Hasapis 02-9436-0055

Monday 2 Feb 2009

SA Branch Committee Meeting North Adelaide SA Australia

Alison Bowman 08-8359-3242

Friday 6 Feb 2009

SA WEN Network Meeting Adelaide SA Australia

Patricia Dames 02-9495-9923

11-13 Feb 2009

Membranes & Desalination Speciality Ill Conference AWA Events Sydney NSW Australia 02-9436-0055

23-26 Feb 2009

Implementing Environmental Water Allocations Port Elizabeth South Africa

16-18 Mar 2009

Ozwater '09 Melbourne VIC Australia

AWA Events 02-9436-0055

WSUD09: Towards Water Sensitive Cities & Citizens Perth WA Australia

Catherine Miller 0416-289-075

14-17 Jun 2009

IWA Instrumental Control and Automation Cairns QLD Australia

AWA Events 02-9436-0055

23-25 Jun 2009 Thu, 25 Jun 2009

Water Conv ention 2009 Singapore

21 -25 Sep 2009

IWA REUSE 09 Brisbane OLD Australia

AWA Events 02-9436-0055

IWA Efficient 2009 Sydney NSW Australia

AWA Events 02-9436-0055

5-8 May 2009

25-28 Oct 2009

3 0 DECEMBER 2008 water

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feature report

Ecosystem Response Modelling in the Murray-Darling Basin

By Ian Overton, Leader, Environmental Water, CSIRO's Water for a Healthy Country Flagship and Dr Neil Saintilan, Head, Rivers and Wetlands Unit, NSW Department of Environment and Climate Change Understanding how the health of ecosystems across the Murray-Darli ng Basin (the Basin) respond to changes in water availability, including impacts from a future changing climate, was the focus of a November 2008 meeting of scientists and wat er managers from around the Basin.

More than 100 delegates met in Sydney to share their approaches to modelling the environment, as part of efforts to help water managers restore the environmental health of the Basin 's rivers, wetlands and floodplains.

To help determine water requirements for sustainable healthy ecosystems, researchers are creating models that link ecological responses to changes in water flow regimes.

Context The health and sust ainability of water ecosystems in the Murray-Darling Basin are under threat due to development, altered land use and a changing climate. These systems are important as they:

developed by the Authority. At the conference he called for the increased development of integrated defensible ecosystem models that can be used to inform sustainable water allocations. Central to the Basin Plan wi ll be sustainable diversion limits on water use in the Basin to ensure the longterm future health and prosperity of the Murray-Darling Basin and to safeguard the water needs of the communities that rely on its water resources. Under the Intergovernmental Agreement, the first Basin Plan is due by 2011.

Presentations Presentations focussed on modelling of: • whole water-dependent ecosystems including rivers, wetlands and floodplains.

• components of the ecosystem including native fish, water birds, frogs, aquatic vegetation, floodplain vegetation, plankton and primary production .

• work to replenish and purify water resources

A range of ecosystem modelling case studies were presented for the:

• are important assets for fauna, flora and heritage

• Narran, Paroo and Warrego Rivers in the North of the Basin

• offer places for recreational activities • supply water to many urban areas and agricultural industries

• Gwydir Wetlands, Macquarie Marshes, the Lachlan and Murrumbidgee Rivers in New South Wales

• are iconic sites for tourism.

• Goulburn River in Victoria

Many systems are now degraded or under threat, such as the waters of the internationally-recognised Coorong, situated at the mouth of the River Murray, which have salt levels up to four times that of sea water. Intense use of wat er in the Murray-Darling Basin is also leading to serious declines in Red Gum forests, fish and waterfowl populations.

• Ecosystems of the River Murray including the BarmahMillewa Forest, the Chowilla Floodplain and LindsayWallpolla Islands region and the Coorong and Murray Mouth region.

The major challenges facing scientist s in predicting ecosystem health include unknown cl imatic conditions coupled with ecosystems that are currently experiencing a drought of proportions not seen in the last 100 years.

Purpose Director General of the NSW Department of Environment and Climate Change, Lisa Corbyn, and Dr Bill Young , Healthy Water Ecosystems theme leader from CSIRO's Wat er for a Healthy Country Flagship, opened the conference. They spoke about the need for a better understanding of ecosystem health across the Murray-Darling Basin under both current management and climate change.

Twenty six presenters at the conference focussed on ecosystem response modelling req uirements, methods and challenges. The modelling approaches highlighted at the conference will aid water managers in their task of restoring the environmental health of the Basin's rivers, wetlands and floodplains. They can also be used to investigate trade-offs between environmental, economic and social benefits from the future allocation of a shrin king water resource.

Dr Tony McLeod from the Murray-Darling Basin Authority explained the planning process for the new Basin Plan to be

34 DECEMBER 2008 water

Additional introductory talks covered the science and management challenges in the Basin and the needs of The Living Murray program.

Researchers were able to share their approaches to data management and to focus on methods to utilise existing dat a and monitoring programs.

Outcomes The major outcomes of the conference covered the broad areas of scientific endeavour associated with ecosystem modelling: • Inventory and health assessment. Attendees called for improved inventory work including the health and extent of water-dependent ecosystems in the Basin and for their hydrology to be used as baselines to assess changes in ecosystem health. This included a need for improved assessment of 'health' versus condition.

• Data shortage. Attendees were particularly concerned by a lack of long-term monitoring projects that can demonstrate the link between changes in hydrology and changes in ecosystems. Empirical and scientifically robust measurements of ecosystem change were called for across multiple spatial and temporal scales in all areas of ecosystem science.

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feature report • Ecosystem responses. Ecosystem managers require

explicit links between hydrology and ecology with ru les that can guide the management of flows and water levels.

Ecohydrology responses are most easily combined when they are in the form of prescribed hydrology variables predicted to create a variable or threshold response in particular components of the ecosystem. Relationships are further complicated by other factors such as salinity, water quality, land management and complex interactions between organisms.

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• Complexity of ecosystem science. Challenges identified

were: the non-linearity of ecosystems; transferability of responses to other river systems or wetlands; lack of data on many components of the ecosystem; and the unpredictability of ecosystems. There were multiple calls during the conference for improved complexity of models to inc lude multiple spatial and temporal scales. Many

All urban design and water professionals are invited to share experiences with some of Australia's leading water, climate and social scientists and help build the capacity and leadership skills necessary to fast track our transition to creating water sensitive cities in Australia.

ecosystem functions such as bird breeding li nks to wetland inundation need to be considered at a basin scale rather than an individual wetland. Temporal responses include hydrological requirements across the time of bird nesting, fledging and feeding of young for successful breeding to occur.

• Whole ecosystem function. A method of identifying the risk

of ecosystem changes going to new ecosystem states was presented for the Coorong and Murray Mouth reg ion.

Understanding ecosystem changes requires not just an understanding of individual component responses to changes in hydrology but the whole ecosystem function.

CAPACITY BUILDING & LEADERSHIP WORKSHOPS

Ecosystem function requires ecological and geomorphological states to function across the biogeochemical, energy and food web cycles. Measurable evidence in changes in ecosystem function are limited in scientific research.

• Economic and social costs and benefits. The meeting

heard a call for the cost of environmental flow releases to be

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considered in terms of the cost of the water and the value from the improved health of the ecosystems. One role of healthy ecosystems is to provide ecosystem services that can be measured in economic terms. This allows changes to hydrology to be valued in a dollar sense from the loss of these services. Ecosystem response models can be integrated with models of economic and social costs and benefits. One presentation proposed a method for the integration of environmental, economic and social models for water allocation and prioritisation of environmental flows.

The meeting was jointly hosted by CSIRO's Water for a Healthy Country Flagship, the NSW Department of Environment and Climate Change (DECC) and the Australian Government's Water Smart Australia program and organised

by Dr Neil Saintilan (NSW DECC) and Ian Overton (CSIRO).

Conclusion The presentations from the conference will be developed into articles. These w ill form chapters fo r a book tit led Ecosystem Modelling in the Murray-Darling Basin that will be published by CSIRO Publishing in late 2009.

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water reuse

REUSE IN WESTERN VICTORIA Compiled by E A (Bob) Swinton This article was compiled from submissions from Barwon Water, Central Highlands Water, Caliban Water and Western Water and we acknowledge the original authors for each of the sections.

Background In common with the rest of Southern Australia, Victoria has been subjected over the past ten years to a drought of unprecedented extent, but the worst hit has been to the west of Melbourne, with regional cities such as Bendigo reduced to less than 10% storage capacity and some cities placed on stringent Stage 4 restrictions.

The reaction of the water authorities has been to institute the reuse of treated wastewater, each in a fashion to suit their individual circumstances. One facet mentioned by all has been the significant reduction of the inflow to their treatment plants, as householders, stimulated by the restrictions, not only reduce the use of water within the home but also endeavour to maintain their gardens by using their own grey water, either by buckets or in engineered systems. (For example, Ballarat South inflow has reduced from 25M L per day down to 14ML per day and in recent months as low as 8M L per day).

The region covered is sketched in Figure 1, outlining the areas of each of the authorities, with their approximate population summarised in Table 1.

For the benefit of interstate readers, although Geelong, Ballarat and Bendigo are well-established cities, the 'satellite city' of Sunbury/Melton in Western Water is probably the fastest growing in the whole of Australia.

Regulation The Victorian EPA's "Principles to Establish EPA Environmental Obligations

The publication Guidelines for Environ mental Management: Use of Reclaimed Water ( http://epanote2.epa. vic.gov.au/EPNpublications) lists the restrictions, both on quality and management processes, imposed for both public safety and agricultural/ horticultural sustainability, including definitions of Class A (suitable for unrestricted urban use) down to Class D,

Barwon Water

Geelong Ballarat

250,000 120,000 67,000 135 000

1+ 9 2+9 1 +?

2+5

Note, the 'minor' WWTPs service the small towns in each region and in most cases have had a long history of 'disposal/re-use' of the treated effluent by irrigation of pasture either within the plant area or ad;acent, commonly grazed by sheep or cattle, with winter flows only being discharged to receiving waters. In some small WWTPs this practice is being upgraded where a suitable 'customer' can be found, as detailed below.

38 DECEMBER 2008 water

•

Western Water

Barwon Water

Central Highlands Water

Bendigo

Coliban Water

However, the new EPA Corporate Licences do not imply a preference for reuse over d ischarge to water.

WWTPs (Major and Minor)

Sunbury

•

suitable only for turf farms, woodlots , flowers.

Nominal Population

Western Water

Central Highlands Water

for Water Businesses for the 2008-2013 Pricing Determination", publication 1069, requires water businesses to "Implement the waste hierarchy for sewage management, including water conservation and recycling for sustainable water management ... "

Headquarters

Caliban Water

Barwon Water

•

Figure 1. Urban Water Authority Regions.

Table 1. Regional Authorities of western Victoria.

Authority

•

Note t hat the Victorian EPA is cu rrently holding workshops with stakeholders with the aim of updating these Guidelines and licences.

Barwon Water manages sewerage services and recycled water for a population of over 250,000 people in the Geelong district, on the Bellarine Peninsula, the Surf Coast, Colac, Bannockburn and Winchelsea.

Barwon Water's Water Recycling Strategy was formulated in 2000 to provide a framework to enable a partnership with government, the private sector and the community to establish sustainable water recycling throughout the region to achieve a 25% water recycling target by 2015.

Barwon Water's Recycled Water Policy assesses projects in terms of environmental, economical and technical sustainability, and commercial viability.

Water Reclamation Plants Barwon Water operates ten water reclamation plants that treat sewage to recycled water quality objectives set by the Victorian EPA, with the largest of the plants being the Black Rock Water Reclamation Plant, which operates by an

technical features

water reuse IDEA system, with a design ADWF of 70 MUd and peak of 3XADWF. Treatment at the Anglesea, Apollo Bay, Barwon Prison, Colac and Lorne plants is achieved through activated sludge processes, while Airey's Inlet, Bannockburn, Portarlington, and Winchelsea are lagoon based plants. The small plant capacities range from the 0.240 MUd plant at Winchelsea to the 5.7 MUd plant at Colac.

Recycled water is a priority for all of Barwon Water's water reclamation plants. Recycled water prod uced at the plants that exceeds reuse demand is discharged to t he environment via ocean outfalls at four p lants, to an inland lake at Colac and to irrigate tree lots and pasture at the other five plants.

Each of the plants produce recycled water that exceeds t he Class C water quality object ives. The monitoring systems in p lace allow Barwon Water to quickly recognise any process problems that may arise which could have an adverse effect on quality for recycled water customers.

Figure 2. Irrigation with recycled water provides significant benefits to production of high value crops.

This, as well as Barwon Water's internal reuse of recycled water, amount to an average of 15 percent reuse of treated effluent over the past 3 years - well on the way to Barwon Water's target of 25% for 2015 (Figure 3).

Delivery Arrangements History In January 1998, a local flower grower, Torquay Flower Farm, req uired a supply of water in addition to what was available. They constructed a pipeline from the northern boundary of the Black Rock Water Reclamation Plant to a dam on thei r property 7 kms to the west.

A few years later saw the establishment of a number of other privately f unded schemes including Anglesea Golf Club and a vineyard in the Portarlington reg ion (Figure 2). This period also saw interest grow in recycled water culminating in extension of t he Torquay Flower Farm scheme with t he connection of additional customers including a turf farm and potato growers, as well as the establishment of t he Barwon Heads scheme to the east supp lying t wo golf courses.

Permanent/Long-term use A recycled water scheme is defined as the infrastructure which transfers and delivers recycled water to one or more customers. This is usually just a pipeline, but sometimes includes an additional pumping system. At Black Rock, the recently upgraded recycled water pumping station is able to deliver in excess of 40 MUday to supply three schemes (to t he north, east and west) and has potential for further development.

Barwon Water's recycled water customers have funded any additional infrastructure required to distribute

As well as having to fund their pipeline/connection, customers vest any infrast ructure located in public/crown land to Barwon Water. This usually takes place a few years after construction to allow the customer to receive any tax benefits from their capital expenditure.

Wh ilst th is policy has limited the location and number of customers who can afford to fund infrast ructure, it has encouraged potential customers to prepare a sound business case to ensure the financial viability of using recycled water.

All recycled water supply infrastructure design and construction is approved by Barwon Water's Developer Works process to ensure it is provided in accordance with the required standards.

Rec~led wate r use per application 2005-2008 Drought Relief /Short-term use

(% by volume) Viticulture 9%

During 2004 a number of other customers connected to t he various schemes in operation. These included recreational reserves, another golf course and several vineyards. By 2005, sixteen customers were enjoying the benefits of recycled water.

Agriculture 6%,

Flowers 29%

Other

Following t he many years of below average rainfall and introduction of water restrictions in late 2006, the demand for recycled water increased dramatically. Barwon Water now supplies recycled water to over t hirty customers who use up to 2500 MUa.

recycled water to t heir properties. This has meant that most of the recycled water pipelines have been privately funded, with government grants being received by some customers to assist the funding of their recycled water infrastructure.

0%

Municipal 1%

7%

Figure 3. Chart of usage of recycled water.

As a consequence of water restrictions being introduced during 2006, Barwon Water constructed a recycled water station near the Black Rock WRP. This standpipe supplies Class C recycled water to approved customers for shortt erm or drought relief purposes. The need for recycled water standpipes at other locations is being investigated .

Management/ Environmental Improvement Plans Barwon Water has developed a comprehensive model Environmental Improvement Plan (EIP) that has been

water DECEMBER 2008 39

water reuse approved by EPA Victoria. This model allows Barwon Water to prepare EIPs for its customers without the need for customers having to engage expensive consultants. The EIP model not only covers EPA req uirements, but also documents best practice irrigat ion and general management measures for t he customers' recycled water application.

The EIP model has been based on knowledge gained by Barwon Water through many years of working with various customers with a range of applications, as well as industry best practice. This model wi ll be adopted by all new customers and progressively implemented by existing customers.

Research and Development Salinity Whilst recycled water has proved to be a benefit to customers, some nutrients and contaminants have to be carefully monitored , particularly salinity and phosphorus. In conjunction with consultants, Barwon Water and its customers are managing these issues to ensure any potential risk to the public, environment and crop healt h is minimised or eliminated, for example investigations have been conducted into better irrigation practices.

One of the main limitations to further use of recycled water from the Black Rock WRP is its salinity. Currently at around 1350 mg/ I, the salinity level is expected to increase due to ongoing water conservation initiatives by Barwon Water's residential and commercial customers and the implementation of a new groundwater source at Anglesea, w hich has higher salinity levels than surface water. A trial of Electro- Dialysis Reversal (EDR) technology is about to commence to assess its viability

Figure 4. Demonstration Farm Lucerne trials at Black Rock WRP. Class A standard, which would then enable the higher q uality recycled water to be used in a cooling tower for a new biosolids processing plant currently under construction at Black Rock WRP , as well as potentially for domestic third pipe schemes.

Fodder crops Since 2005-2006, Barwon Water in c onjunction with a local farmer has been operating a Demonstration Farm to trial the production of fodder crops. The aim was to ascertain the benefits of growing several varieties of fodder crop (mai nly Lucerne) by irrigating with the nutrientrich recycled water (Figure 4).

The results clearly demonstrat e that a significant increase in growth rates can be achieved through the use of recycled water.

Biofuel

C lass A upgrade

Duri ng 2006, Barwon Water t ogether with Primary Industries Victoria conducted a feasibility study into the added value of recycled water for growing crops suitable as a biofuel feedstock. This project included a trial growing a Canela crop on Barwon Water's Demonstration Farm at Black Rock.

Barwon Water is also investigating a second stage of increased treatment to

Whilst the Canela was not grown in ideal conditions, the results of the oil and

moisture analyses proved that the additional nutrients contained in the Class C recycled water ensured the quality of the Canola seed was suitable for use as a biofuel feedstock.

Conclusion It seems clear that with the limits that exist to potable water availability, the commun ity will continue t o rely on recycled wat er to supplement potable water supplies for "fit for purpose" applications (Figure 5) . Recycled water schemes are no longer seen as t emporary drought assistance measures, but rather as a permanent com ponent of the water cycle and Barwon Water's aim is to establish the use of recycled water as a key element in the sust ainable management of water as a limited resource. The corporatio n wi ll encourage the commercial use of this valuable wat er resource while ensuring the highest environmental standards in landuse and recycled water management.

Information supplied by Michael Naughton, the Coordinator Recycled Water and Bioso/ids at Banvon Water, email: michael.naughton@ banvonwater. vie.gov.au and Geoff Jones, the Recycled Water Officer at Banvon Water, email: geoff.jones@ barwonwater. vie.gov.au

Central Highlands Water Background Central Highlands Water supplies water and wastewater services to some 120,000.population in the Central Highlands uplands.

The major city, Ballarat, harvests most of its water supply from the Moorabool river system located east of the township.

Figure 5. Recycled Water irrigation at the Bannockburn Golf Club.

4 0 DECEMBER 2008 water

In 1999, Central Highlands Water commissioned a study of its wastewater

water reuse treatment faci lities in an effort to identify opportunities for wastewater management over a 20 year planning horizon. The study is known as the " Long Term Wastewater Strategy" (LTWS), this accounted for the regu latory framework of the day which emphasised a preference for reuse of treated effluent and removal of effluent from surface waters.

Since early 2000, the LTWS has guided the development of Central Highlands Water's 11 wastewater treatment facilities and via the Essential Services Commission 's Water Planning process, has lead to significant capital investment.

Table 2. Recycled Water Target.

Year

08/09

09/10

10/11

11/12

12/13

Recycled water target

10.9%

12.5%

13.2%

13.7%

15.8%

Strategy includes an action to continue discharge of 2,000ML of recycled water to the Leigh River (Yarrowee) each year.

In the event that CHW is able to negotiate with EPA that the above mentioned 2000ML flow is considered "reuse" as environmental flows, then the percentage of recycling from Ballarat South would increase from less than 2% to 35% reuse.

Water Reclamation Plants Central Highlands Water operates two major WWTPs, Ballarat South (8000 MUa) and Ballarat North (2200 MUa) and eight regional plants ranging down from 500 MUa at Maryborough to ca. 50 MUa for the smaller townships.

Ballarat South The Ballarat South wastewater treatment plant produces tertiary treated effluent which is discharged to the Yarrowee River in accordance with EPA licence.

Recycling at this facility includes approximately 120MUa for onsite processes, and up to an additional 40MUa commencing in 2008 for the City of Ballarat's Marty Busch sports precinct.

Whilst debate continues between EPA and the water industry around the environmental benefits of environmental discharges and the legitimacy of claimi ng them as environmental flows, or "reuse", it is important to note that page 25 of the Central Region Sustainable Water

Summary Of Central Highlands Water's 10 wastewater systems, 7 small systems are already recycling 100% of reclaimed water.

Of the three remaining systems:

Ballarat North

The degree of recycling planned for the future is listed in Table 2.

However, Clunes WWTP has a TDS level of 4000 mg/L due to use of bore water during the drought. The 100 MU a plant at Beaufort is planned to be upgraded.

The discharge from the plant flows into Burrumbeet Creek. One of the major aesthetic, recreational and environmental assets of Ballarat has long been Lake Wendouree (which was used during the 1956 Olympics for the rowing races).

However, in 2006 it was reduced to a mere puddle. The treatment plant has just been upgraded via a DBO arrangement with United Water International to a tertiary BNR process capable of meeting stringent environmental discharge standards with one aim, the partial replenishment of Lake Wendouree.

Maryborough (inflow 700 MUa) is currently supplying Class C water to the golf club, council, and a farmers, with 530 MUa committed until 2015. The balance, including unsold water in wet years, is used on a farm operated by CHW. Daylesford (inflow 450 MUa) has committed all its water to farm land operated by two private agri-business companies, with about 400 ha under irrigation.

All the smaller plants supply water to private agri-business companies.

• Beaufort has been scheduled for an upgrade with a view towards 100% recycling in 2009/1O; • The percentage of reuse at Ballarat North will increase to around 35% following the implementation of the Lake Wendouree reuse project; and • Due to the disproportionately large volume of wastewater treated at the Ballarat South wastewater treatment plant, until a large scale recycling project is implemented in this system, the overall percentage of reclaimed water recycled will remain relatively low.

Information supplied by Andrew Harris, email a.harris@chw.net.au Coordinator Reuse at Central Highlands Water.

Coliban Water Coliban Water is one of the largest Victorian regional urban water corporations with a service area that covers 16, 550 square kilometres. This includes 49 towns extending from Cohuna and Echuca in the north to Kyneton and Trentham in the south; from

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water reuse Boort, Wedderburn in the west to Heathcote and Tooborac in the east. The larger Water Reclamation Plants (WRP) are in Bendigo (Epsom), Castlemaine and Kyneton with smaller WRP's in the surrounding townships. Overall, Coliban Water services 67,000 customers.

Their wastewater strategy dates from 2005 when Waterplan 2055 was developed with the aim of delivering 22,000 MUa of extra water by 2055. One of the proposed options was the Epsom Spring Gully Recycled Water Project to provide 4400 MUa of 'new' water for rural supplies, parks, gardens and sporting facilities, industrial and commercial users and clean passing flows to the Campaspe River during winter. Thus some 11 % of current catchment water wou ld be recycled.

Completion of this project was originally planned for 2009. However, Bendigo's water supply situation continued to deteriorate, culminating in the introduction of Stage 4 water restrictions in September 2006, and an end to the watering of public grounds.

By late November 2006, Coliban Wat er's combined storage was at a mere 10% capacity, the lowest level on record. The very lifeblood of the community was drying up, and it became vital that the project be brought forward to 2007. The project was a collaboration bet ween Coliban Water, the local water authority, and Beca as engineering, planning and project management consultant. They collaborated closely to achieve the project's ambitious timeframe of 12 months from initiation to the official opening of Stage 2 on November 3rd, 2008.

Water Reclamation Plants Coliban Water operates 16 WRP th rough out its region. All of them utilise the

reclaimed for a number of uses involving pasture irrigation, race courses, golf courses and dust suppression. Reuse is conducted on either Coliban Water property or with near-by farmers, thus ensuring 100% reuse.

One of the major WRP's is located in Bendigo (Epsom). It was one of the first purposed-built BNR plants in Australia and has operated to produce Class B water since 2003. Its ADWF design capacity is 5000 MUannum.

The Epsom Spring Gully project had to upgrade the quality to provide Class A standard water that is suitable for irrigation and safe for contact with humans. However, the detrimental effects on plants and soil caused by high levels of salinity in the water over the longer term also needed to be considered. A water quality, beyond Class A, would therefore be necessary.

These outcomes were delivered in two stages.

Stage 1, completed in June 2007, delivered the infrastructure req uired to provide Class A water.

Specifically, it comprised: • a new treatment plant building and transfer pipeline • a 14km, 500mm diameter pipeline to the existing Spring Gully Reservoir • a high lift pump st ation to the new plant, designed for a flow capacity of 27 MUday at a total head of 180m, including a surge prot ection facility • 11 off-takes along along for use in the urban sites.

• chemical dosing, ch lorine treatment and UV treatment Stage 2, completed in early 2008, comprises membrane treatment, designed to reduce nutrients and salinity to 350 mg/L, thereby further improving

the water quality for reuse and environmental flows over the longer term.

It also includes a brine disposal pipeline and brine evaporation lagoons, with a storage lagoon for the winter.

Disinfection, ultrafiltration and reverse osmosis were the preferred options of all treatments considered. They are well proven from both a technical and reg ulat ory perspective, and provided an economic solution.

An electrodialysis plant (EDR) has been included on the reverse osmosis brine stream in order to reduce the volume of brine and therefore reducing the size of the evaporation lagoons.

Water and Environmental Standards The water produced by the selected treatment option needed to meet the fol lowing regulatory st andards: • Class A in terms of EPA Victoria/OHS requirements for reclaimed water (6 log removal of protozoa and 7 log removal of viruses from raw sewage).

• Nitrogen limits of - 3.2 m g/L for rural users and irrigation of parks and gardens, and - 1.1 mg/L for passing flows.

• Phosphorus limits of - 0.1 mg/L for rural users and irrigation of parks and gardens, and - <0.01 mg/L for passing flows.

There are 17 connections to the Class A pipeline which include botanical gardens, sporting facilities, schools, the hospital for gardens, t oilets and the industrial laundry. 350 rural customers in the Bendigo region are also receiving recycled water for their seasonal supply and there are 2 standpipes available for commercial uses such as dust suppression, fire fighting and concrete batching.

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technical features

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water reuse The total project cost was $47 million, with the State Government providing $6.55 million) and National Water Commission $6.3million.

Information supplied by Phil Fasham, Manager Water Resource Planning.

Email Phillf@coliban.com.au

Western Water Western Water services over 53,000 properties, a nominal population of 135,000, in the expanding region to the northwest of Melbourne, including the towns of Woodend , Romsey, Lancefield, Macedon, Riddells Creek, Gisborne, Sunbury, Diggers Rest, Melton, Bacchus Marsh and Myrniong. Population growth for this region is currently at 3.27% - well above the Victorian average.

The Western Water service area 3,000 square kilometres - is a combination of urban and rural living, with a significant proportion of land devoted to agricultural uses, mainly grazing and cropping .

Water Reclamation Plants Western Water operates seven recycled water plants - at Woodend, Romsey, Riddells Creek, Gisborne, Sunbury, Melton and Bacchus Marsh - where sewage and trade waste collected from domestic, commercial and industrial customers is treated and recycled with a strong focus on drinking water substitution.

The largest Plant is located at Melton with an ADWF of currently 9MUD with an imminent upgrade increasing the capacity to 18MUD. A Class A Recycled Water Plant is a new addition to the Melton site with supply to the new Eynesbury Township for residential use use 2900 homes is expected to commence in December 2008 for toilet flushing, garden watering, fire fighting and public open space irrigation. Further dual pipe reticulation is planned for Toolern area in Melton South for another 19,000 lots by 2030.

The Sunbury Recycled Water Plant is the second largest plant and currently treats up to ?MUD. However with water conservation drastically reducing inflows to the plant, new averages hover around 4.5MUD with flows dropping to as low as 3MUd during the peak of summer. The plant produces Class B recycled water, the majority of which is transferred to customers of the Sunbury Melton Recycled Water Scheme and the remainder is discharged to Jackson's Creek under licence c onditions.

44 DECEMBER 2008 water

Figure 6. Waiting to fill up at one of the recycled water standpipe.

History Recycled water was definitely not "core business" in the water sector 1O years ago - it was called, and treated as, waste.

In 2001 , Western Water established a Recycled Water Business Unit out of a desire to look for innovative solutions for new water supply options and potable substitution for on-going drought cond itions. Generic principles for operation were established, potential customers were consulted and the business successfully developed the award winning Sunbury-Melton Recycled Water Scheme as its signature project.

The Sunbury Melton Recycled Water Scheme Class B recycled water was sourced from the Sunbury Recycled Water Plant and did not require further treatment, but developing the Scheme required more than two years of community and customer consultation to ensure the pipeline alignment was optimised and service standards for the Scheme met customer requirements. Willingness to pay was also assessed as part of this process.

Delivery of the recycled water involved the installation of fixed assets such as balancing storage, metered connections, pipes and pumps. Signing up customers required standard commercial contracts, which outline contracted volumes of water delivered to customer at a minimum specified rate and for a period of up to 15 years.

In subsequent years, the SunburyMelton Scheme has had a number of pipeline extensions to sporting ovals and horticultural precincts, with more than 60 customers now signed up to take about 1,000 MUa of recycled water.

Reticulated Class B & C Recycled Water is supplied for uses such as: • for agribusiness (vineyards (including Witchmount Winery - winner of the World's best shiraz), olives, citrus, Xmas trees, Lucerne, canola etc) • for recreation (golf courses, football & cricket ovals (including Salesian College - birthplace of The Ashes), school ovals, little athletics tracks, croquet & lawn bowling greens, horse racing tracks, rugby & soccer pitches etc) • for councils (road construction & maintenance, street tree watering, dust suppression , public open space irrigation etc However, as water became more scarce and water restrictions more stringent, farmers, businesses and local councils began looking for temporary, accessible sources of water - not necessarily of drinking water standard for regions beyond the reach of the Sunbury-Melton Scheme. This included water for d ust suppression , roadworks, street tree and landscape watering, amongst others.

Temporary Supply - a Drought Relief Initiative Initially a single recycled water standpipe was constructed onsite at the Sunbury Recycled Water Plant. It shared a pump with the treatment plant and truck drivers had to drive through the plant to access it. Temporary supply was also made available at two other unmanned sites, wh ich involved the Council using eductor trucks to take recycled water from the final lagoons.

Other options were investigated, such as setting up depots on existing pipelines and on customers' or public land.

technical features

water reuse three additional standpipes have subsequently been constructed at Gisborne, Melton and Romsey RWP's to keep up with demand.

By adapting established internal procedures, Western Water was able to develop a robust method for ensuring the Drought Relief Initiative was well managed and regulated.

Procedures included inspection of each applicant's property and examination of intended use to ensure compliance with the EPA Victoria's Reclaimed Water Guidelines, covering onsite storage, potential for spills and potential exposure to the public.

In addition, prior to the issuing of a carter permit, each carter was required to be inducted into the use of the standpipe and recycled water. Random audits, once permits and agreements were approved, were also conducted to ensure continuing compliance with the Guidelines.

Standard documents were developed as part of the process and approved for use by the EPA Victoria. The documents include: • Temporary Recycled Water Supply Agreement - Contract clearly defining the responsibility of each of the parties • Recycled Water Carter Application - A detailed form requesting information from the applicant to allow a thorough assessment of their suitability for transporting recycled water • Recycled Water Carter Permit - Sets out the strict requirements that the carter must adhere to when delivering recycled water • Customer Site Management Plan - A detailed management plan covering environmental, public health and OH&S requirements when using recycled water

Table 3. Number of agreements and volumes used are continually growing.

Year No. Temporary Supply Agreements

2002/03 18

Volumes Used (MUa)

2003/04

2004/05

2005/06

2006/07

2007/08

44

45

27

61

55

19

18

8

22

19

• Recycled Water Trucking Recording Sheet - A recording log located at each standpipe that required each permit holder to register volumes, meter reading, carter and permit holder details.

Risk Management It was important to ensure all regulatory issues and potential risks to Western Water were addressed. In order to meet EPA Victoria Guidelines for the Use of Reclaimed Water, a number of strict requirements needed to be met.

1. Western Water must notify EPA Victoria where the water is used and how much 2. Western Water must be able to protect public and environmental health 3. Each customer application must be assessed to ensure it is able to comply with EPA Victoria Guidelines, and there must be a management plan established for each site where recycled water will be used 4. The owner of the property must act in a responsible manner 5. The carter of the water must act in a responsible manner Potential risks to Western Water were addressed using established risk management procedures. Risks were identified, measures put in place to mitigate these risks, and actions noted in Western Water's Risk Management Register.

Staff selection also played an important role in the establishment of the new function. To ensure the various risks

were well understood and addressed, staff with specific skills in risk assessment, customer service, contract development and management, plumbing and environmental disciplines were recruited to be part of a team to establish the Drought Relief Initiative.

A Working Model for Success The recycled water business at Western Water operates under six guiding principles: 1. Ensuring Recyc led Wat er projects are environmentally sustainable 2. Increasing public awareness and education of the benefits of Recycled Water 3. Developing markets for potential users of Recycled Water 4. Ensuring commercial viability of Recycled Water projects 5. Ensuring risks are understood and managed by the most appropriate stakeholder 6. Offering a transparent process to ensure equity.

Western Water is now supplying more than 60 Temporary Customers (Table 3) and has approved 61 Recycled Water Carters.

Continued over page

46 DECEMBER 2008 water

technical features

water reuse

RISK MANAGEMENT REVIEW OF THE ROUSE HILL DUAL RETICULATION SCHEME G Landers, S Mcleod Abstract

Ongoing risk

At Rouse Hill and surrounding suburbs Sydney Water owns and operates the largest residential dual reticulation scheme in Australia. As part of its ongoing management of risk, Sydney Water recently finalised a review and update of risk assessments on the .

Rouse Hill scheme. Sydney Water engaged a joint venture of Sinclair Knight Merz and Hunter Water Australia (SKM/HWA) to facilitate and report on the risk review as well as providing external assessment of Sydney Water's processes.

management for recycled water systems.

• some new areas of potential improvement were ident ified for consideration as part of continuous improvement • there is a need to maintain the efficacy of existing controls especially with respect to cross connections - the controls themselves may well change as a result of changing asset delivery practices

The key findings of the review were that: • the risk management controls Sydney Water had in place were effective

Dual meters and recycled water tap with special fitting.

Continued from previous page

Three of the four Councils within the reg ion are using ONLY recycled water for road maintenance and street tree watering and there is frequently a queue at the three standpipes (Figure 6).

Some trucking companies are transporting recycled water from Western Water more than 70 kilometres outside the region, because alternative sources are not available.

Western Water's Recycled Water Team is receiving more and more enquiries, with upwards of 10 calls a day and sometimes processing as many as six applications a week.

requirements, based on experience, about the types of applications that are an acceptable risk to the business.

Conclusion Recycled water is an important alternative resource and should be considered part of the solution to our water shortage, particularly during drought.

But it must be treated with the respect it deserves. Class B is not drinking quality water and its supply and use is not without risk. However, adequate controls can be put in place to ensure any risks are understood and properly managed.

Western Water does not accept all applications. Under EPA Victoria's Guidelines, Class B recycled water cannot be used in residential settings for garden watering and requires restricted public access for four hours after watering public open spaces (refer Figure 1).

By establishing an application assessment process, generic contracts, conditions and permits, a transparent and equitable process can be ensured for each application and can help alleviate the risks associated with Recycled Water Supply.

Western Water assesses each application and we have our own strict

Water Authorities wi ll need to continue to be innovative with water

• identified risks have been reduced to acceptable levels with the effective implementation of current control measures.

However reductions in risk may be possible with suggested

resource management. Recycling is not the only answer. It is, however, a resource t hat needs to be put to its best use. For example, just complying with a regulators licence to discharge wastewater rarely achieves the most sustainable outcome.

Western Water currently recycles 86% with the aim of recycling 100% by 2013. The National Water Commission has reported that Western Water was the leading water recycler in Australia in 2006. It has been a finalist in the Victorian Banksia Environmental Awards, won the Premiers Sustainability Award and has been recognised locally as a leader in environmental sustainability.

It offers a bird's eye view of the future of the Australian Water Industry.

Information was supplied by Stephanie Gillespie, Manager, Renewable Resources, Western Water, email: stephanie.gi/Jespie@ western water. com.au.

water

DECEMBER 2008 47

water reuse investigations into new control measures.

Although not within the scope of this exercise, a further key finding was that the single highest risk to public health is from cross connections in privately operated dual reticulation or decentralised schemes where Sydney Water supplies the drinking water.

When the scheme came on-line operational experience showed that the total number of hazard events and individual risk consequences had increased and the risk assessment was reviewed. The key recommendations were that Sydney Water: • maintain the existing effectiveness of controls especially for addressing cross connections • update the risk register in its ISO accredited management system and develop a plan for investigating suggested further risk control measures • regularly review its risk register and the effectiveness of its controls • investigate the emerging issues identified during the exercise and whether controls are required for these An independent peer review of the exercise supported its findings and recommendat ions. The peer review stressed that Sydney Water develop a plan w ith specific timings to address actions arising out of the review.

Introduction Sydney Water actively pursues recycled water opportunities where economically and environmentally viable and where contributions to water conservation outcomes can be made. Across greater Sydney there are more than 20 recycled water schemes that recycle around 22 billion litres of wastewater a year. The amount of recycled water used in greater Sydney has more than doubled in the past 10 years.

water scheme. The Rouse Hill Recycled Water Plant in Sydney's northwest, supplies 17,000 homes with 1.4 billion litres of recycled water a year. The number of properties supplied is continually increasing and eventually the scheme will serve 35,000 homes.

Recycled water plants and pipel ines are also under construction in new suburbs in Hoxton Park and Ropes Crossing near St Marys. The other major dual reticulat ion scheme in Sydney is the WRAMS Scheme operated by t he Sydney Olympic Park Authority that supplies 886 million litres of recycled water a year. Drinking water is also supplied by Sydney Water to all of these areas.

The Rouse Hill scheme commenced operat ion in August 2001. Prior to t his Sydney Water conducted an extensive risk assessment and review of legal obligations. These exercises formed the basis of a risk management plan which was reviewed by NSW Health. Essential actions were completed prior to the commencement of the scheme and noncritical actions were progressively finalised.

The risk control measures put in place have been regularly audited to ensure effectiveness. Any identified gaps have been addressed using Sydney Water's ISO accredited q uality management system. It is electronically administered using Lotus Notes™ and has document control, records management and contin uous improvement functionality.

During the operation of the scheme, there have been four cross connections between drinking water and recycled water. In addition there was one cross connection in the Olympic Park scheme.

By the term "cross connect ion" we consider physical links between potable and recycled water systems as well as incorrect connections of potable fixtu res to a recycled pipe where recycled water was supplied for potable uses. Th is usually occurs t hrough p lumbing defects on properties.

The New South Wales Government's 2006 Metropolitan Water Plan outlines the Western Sydney Recycled Water Initiative which will provide 27 billion litres of recycled water a year for dual reticulation for 160,000 new homes, as well as for agriculture, industry and environmental flows. By 2015 the amount of wastewater recycled in greater Sydney will increase to around 70 billion litres a year or 11 per cent of Sydney Water's supply.

In line with its quality management system, after each of these incidents Sydney Water reviewed its risk management procedures and modified these as req uired. In particular, the checks on pl umbing work prior to final connection of properties to recycled water became even more rigorous. Since 2004 there have been no further cross connection incidents in t he Rouse Hill system.

Sydney Water currently manages Australia's largest residential recycled

Since commissioning in 2001, the Rouse Hill scheme has transitioned into a

48 DECEMBER 2008 water

normal operational phase under the same quality management system for water and wastewater operations. However, some of the context in which the scheme operates has substantially changed.

Increasing pressure on drinking water supplies, mainly from cl imate change, drought and population growth has led to the increasing importance of recycled water for delivering a sustainable water supply to Sydney. A major component of Sydney's recycled water initiatives is dual reticulation schemes for new growth areas.

Another sig nificant change has been the introduction of BASIX, which is an important element of t he NSW Government's strategy to increase water and energy savings. The package enables a wide range of measures for reducing potable water demand.

In NSW the Water Industry Competition Act (WICA) has been passed through Parliament and is being implemented.

This enables entities other than public utilities such as Sydney Water to acquire a licence to supply water (potable, recycled, stormwater, etc) and sewerage services. This has enabled privately owned and operated sewerage and recycled water schemes with one such scheme under construction.

The combination of BASIX and WICA has increased the complexity of water and wastewater servicing arrangements.

More options and combinations of options are available to developers for meeting mandated targets. For example, Sydney Water may plan to provide dual reticulation for a large development area.

However, in meeting BASIX requirements, individual developers in the area may choose to use recycled water from the dual reticulation network, or use other means such as rainwater harvesting or combinations of these. This affects Sydney Water's asset sizing and delivery as well as increasing demands on managing cross connection risks.

In addition, although the Australian Guidelines for Water Recycling Phase 1 (2006 AGWR) have been released, the Rouse Hill scheme operates under the 1993 NSW Recycled Water Coordination Committee Guidelines. The 2006 AGWR represent a significant sh ift from these previous guidelines from a more riskimplicit, end point focussed set of guidelines to a more risk-explicit, process focussed set of guidelines. In consultation with NSW Health, Sydney Water is seeking to implement these guidelines for all new schemes and over time to existing schemes.

technical features

water reuse • Post workshop review and finalisation of results

During the course of operating , maintaining and augmenting the Rouse Hill scheme Sydney Water has encountered new situations and acquired a large amount of knowledge and experience. Sydney Water clearly identified a need to transfer the learning from the Rouse Hill to all of its new recycled water schemes.

• Development of Action Plan for Sydney Water to progress • Throughout the process review sessions by small groups of Sydney Water staff in their respective areas of expertise to address items raised during the workshops

In light of these contextual changes and of the knowledge and experience acquired through operation of dual reticulation scheme, Sydney Water decided to conduct a review of its risk assessment for dual reticulation schemes. This is in addition to its current risk-based management processes in its quality management systems.

Sydney Water engaged a joint venture of Sinclair Knight Merz and Hunter Water Australia (SKM/HWA) throug h its Engineering and Planning Services Panel to facilitate and report on the risk review as well as providing external assessment of Sydney Water's processes.

The objectives of this review were to: • Provide external assessment of risk controls, especially plumbing and cross connect ion controls • Reassess risk profile to account for new issues • Transfer the learning from several years of operation of the Rouse Hill scheme to new dual reticulation schemes currently in planning and delivery stages The scope of the review was limited to Sydney Water-owned and operated dual reticulation recycled water schemes. The review considered risk under several classifications according to the cat egories in Sydney Water's corporate risk framework. Although a major focus of th e review was health and environmental risks, the project team

Level ofRisk Matrix

Very Likely

The project team used Sydney Water's corporate risk framework. This is a qualitative process based on AS/NZS 4360. The three basic steps are: • Identify - hazards and hazard events • Analyse and Evaluate - risks and the impact of current controls • Treat - risks, developing a risk management plan

Parklea WS 449 Recycled Water Reservoir.

also reviewed other risks which can be more broadly grouped as "business" risks. This includes, for example, financial, asset performance and reputation risks.

Process The process for undertaking the risk refresh was as follows:

During this assessment:

• Review of existing material

• hazards and hazardous events were identified and documented

• Two workshops on Risk Identification , Assessment and Controls

• the level of risk for each was estimated

• Post Workshop review and finalisation of results • Third Workshop to assess Control Effectives and address Priority Hazard Events. The third workshop was also used to obtain sign off on risk assessment identification and ranking outcomes from workshop participants.

Likely

Catastro Severe

Unlikely

ery Un like ly

2

3

3

4

Moderate

2

3

4

5

M inor

3

4

5

6

Insignificant

4

5

6

6

Figure 1. Sydney Water risk matrix.

The purpose of such a qualitative assessment is to provide general direction rather than detailed quantitative analysis. This approach provides focus and priority for risk management actions.

To this end the project team relied on input from technical experts and experienced personnel across the relevant business units in Sydney Water.

Workshop participants based their assessments on quantitative data whenever this was available.

• significant risks (consequences) were identified • priorities for risk management were documented • risk management controls were allocated to the most appropriate business unit.

Workshop participants reviewed each hazard event consideri ng causes and consequences by type, fol lowed by current risk controls. Sydney Water has a range of consequence categories and frequency definitions wh ich are similar to those developed by most organisations which base their method on AS4360.

Workshop participants allocated ranki ngs based on the defined descriptions for likelihood and consequence in the Sydney Water Corporate Risk Management Methodology. The Sydney Water risk matrix is shown in Figure 1.

Workshop participants assessed individual conseq uences for each hazard event for three states:

water DECEMBER 2008 49

water reuse • Uncontrolled risk (inherent risk) • Current residual risk (risk with current controls in place) • Anticipated residual risk (target risk with future controls in place) There is an argument that there is no such thing as a purely uncontrolled risk and therefore no real point in assessing it. However, assessing the "inherent" or uncontrolled risk prior to current residual risk, albeit with some assumptions, demonstrates the impact of existing control measures. This also highlights the most significant controls in place which have to be monitored to ensure that they remain in place effectively. Workshop participants then assessed whether the current residual risk is acceptable or whether improvement can be made. The anticipated residual risk shows the estimated risk profile once further control measures have been implemented.

The consulting team used preparatory sessions to review in detail specific areas such as plumbing controls. The results of these sessions enabled informed evaluation of risks and controls during the workshops.

Review sessions post-workshops allowed a smaller group to consolidate results and ensure consistency in scoring and assessment. These forums also allowed the project team to seek further specialist advice on areas where workshop participants required further input to assess risk.

The final report and outcomes were also subject to review by senior management and external peer review.

Key Findings and Discussion The main findings of the risk review are listed and discussed by consequence category below. The overall main find ings of the review are: • Sydney Water's current controls are effective at managing the risks associated with dual reticulation schemes.

• Workshop participants proposed several additional risk reduction measures for further evaluation. These require significant investigation and assessment of cost benefit, given the currently acceptable risk profile.

• This exercise highlighted the importance of maintaining the effectiveness of the controls from source control (trade waste) through treatment to distribution and

50 DECEMBER 2008 water

communications with customers. Th is is especially so for cross con nections.

This applies equally to Sydney Water and privately owned and operated dual reticulation schemes and covers construction and installation of Sydney Water and privately owned assets.

• Several new potential hazards were identified for further investigation and action. These have arisen from experience with the operation of the Rouse Hill scheme and from preparation and planning for the first decentralised and private dual reticulation schemes in Sydney Water's area of operations.

• Sydney Water has robust risk assessment and risk management processes and should continue to follow these for addressing emerging risks.

The following sections consider some of these in more detail.

Health Health risks are typically dominated by acute microbial risks rather than chronic risks. The review concluded that all health risks were acceptable and that current controls were adequate.

Two of the primary risk controls with the greatest reduction in potential health risk are the treatment process and cross connection controls. The review highlighted their importance in protecting public health.

The hazard events which potentially give rise to cross connections remain among the key hazard events. The review found that the current cross connection controls were comprehensive and adequately addressed cross connection risks. The review recommended no changes to the plumbing inspection program but noted potential changes in asset delivery which would affect the number and type of inspections. In light of this, the review recommended that the efficacy of the current cross connection controls be maintained even though inspections might change with changes in asset delivery. The review also recommended further actions to utilise the data acquired over several years of operation to further characterise causes and investigate alternate means of addressing these.

The review also showed that, in the Rouse Hill system, Sydney Water has very direct influence over the control measures implemented to mitigate risk.

Examples of these are that Sydney Water: • has extensive source control measures, such as its trade waste programme • operates the wastewater and recycled water plants as well as the distribution system under certified quality management systems • has a rigorous plumbing inspection program targeting cross connections.

Participants identified several emerging health issues during the course of the workshops. These new risks arose mainly from new governance arrangements or potential poor implementation of new technologies. Sydney Water currently has solid risk controls during design, delivery and ongoing operation and maintenance of its recycled water systems. Sydney Water can not insist upon application of these same controls in private dual reticu lation systems where Sydney Water supplies on ly the drinking water.

Based on material reviewed during this project it became apparent that, without appropriate risk controls, these types of private dual reticulation syst ems pose a very high risk to public health. This applies particularly to consistency of treatment and cross connection controls. It results from the fact that, in these cases, there is a shared responsibility for the control of risk, or less direct capacity to influence risk control. This same risk applies t o decentralised recycling schemes albeit on a smaller scale. As demonstrated by examples in other jurisdictions, this is a real and distinct possibility with the public utility, being the "supplier of last resort", having to address gaps in risk controls.

This assessment shows that risk management requirements should be consistently applied to all dual reticulation schemes to ensure that all consumers receive the same level of prot ection. This requires development of consistent governance arrangements for managing these public health risks.

Using its own experience in managing risks from dual reticulation systems Sydney Water will assist regulators as required.

technical features

water reuse Environment Unlike health risks, the environmental risks identified for the Rouse Hill scheme are typically chronic rather than acute, requiring longer time frames to characterise. The review also found greater uncertainty in dat a assessment for environmental impacts than for health impacts.

Environmental risks were considered acceptable, with current data showing no apparent environmental impacts from the scheme at Rouse Hill. Although there are controls in place for identified environmental risks, the review recommended further data analysis to address the uncertainties in data and the longer t ime frames required to more fully assess risks.

The review also identified emerging environmental risks with dual reticulation: â&#x20AC;˘ Recycled water as a scarce resource â&#x20AC;˘ Energy consumption in operating dual reticulation schemes.

Other business/asset risks The review noted that current control measures adequat ely addressed the business or asset risks identified in previous work. However, operation of the Rouse Hill scheme and development of new dual reticulation schemes have identified new risk areas. Many of these new risks come from the integration of new technologies and coordinating recycled water delivery in new developments. One example of this is integrating the delivery of dual reticu lation in the context of BASIX with developers able to choose other water supply options to achieve the BASIX wat er savings target. In addition, unlike the Rouse Hill development, new dual reticulation schemes have a multiplicity of developers. This poses a risk in coordinating the planning and delivery of these new dual reticulation schemes. It also poses a risk in effectively training a new group of contractors and workers on dual reticulation requirements, especially plumbing controls.

Some of these risks also have a health consequence. In particular, where developers choose to implement their own recycled water systems with Sydney Water continuing to supply potable water, there is a lack of clarity about the process for ensuring implementation of effective system and planning standards and risk controls such as those used by Sydney Water. How these risks are managed across boundaries is yet to be addressed and will become a key

management issue with private recycled water schemes.

The review recommended that Sydney Water investigate options to review these interface risks to its potable water network and thence to public health.

Comparison with previous risk assessments The number of hazard event s and consequences increased from the original risk assessment prior to the commencement of the scheme. Th is result was to be expected since the data and experience from several years of operating dual reticulation schemes were now available for this review.

Notwithstanding this, this review confirmed many of the results of the original work . In itself, this is a tribute to the work conducted by the original assessors. Without any previous experience of operat ing dual reticulation schemes they identified and successfu lly managed the foreseeable risks associated with such schemes.

Several of the risks identified in the initial risk assessment are no longer risks in the current environment. These mainly were to do with aspects such as customer accept ance. At the time this was indeed a true risk, since no-one exactly knew how the public and customers would react to this innovation.

However, public acceptance of recycled water has dramatically changed since the Rouse Hill scheme began. Such schemes are clearly well received by Sydney's public and form part of the accepted wat er supply.

Another example was that ext ernal experts who participated in the initial risk assessment identified instances where other recycled water schemes had fallen down from a lack of a "champion" within in the utility. They suggested that this was a risk to the Rouse Hill scheme at the time. From the beginning of the Rouse Hill scheme, Sydney Water's commitment in people and resou rces addressed this risk. Now, recycling is an integral element of Sydney's supply strategy.

Sydney Water's ongoing risk management and review work, of which this exercise is part, demonstrates that Sydney Water has in place systems to continuously manage risk.

Future Directions Since risks are adequately controlled by existing measures, most of the Improvement actions are more investigative and planning. Across all of

the hazard events the review recommended several new measures for further investigation and action. This is in addition to maintaining current controls through Sydney Water's quality management system. Since these new measures were listed under individual hazard events, some were duplicated and others were very similar.

Through its operational and planning committees for recycled water systems, Sydney Water has since reviewed the recommended new measures from this exercise. Th is review process consolidated the recommended new measures into 32 actions. As part of the process, Sydney Water allocated responsibi lity for progression of actions to the relevant business units. The management committees wil l track these actions using Sydney Water's quality management systems.

The results from this risk review are being used in developing a new recycled water quality management plan for dual reticulation schemes in line with the AGWR Phase 1 .

Acknowledgments The authors thank the workshop participants from Sydney Water and SKM/ HWA as well as John Anderson (i ndependent peer reviewer) for their contribution to this work.

The Authors Gavin Landers is a Product Strategy Planner, Sydney Water, with nine years of experience in a variety of operations and asset management roles across drinking, recycled and waste wat er.

Email gavin.landers@sydneywater. com.au. Stacy Mcleod is an Associate Senior Communication Adviser for SKM , and is experienced in project management and communication programs for recycled water in both Queensland and NSW, email smcleod@skm.com.au.

Bibliography AS/ NZS 4360, 2004: Risk Management NRMMC, EPHC, AHMC, 2006, Australian Guidelines for Water Recycling: Managing Health and Environmental Risks (Phase 1) NSW Recycled Water Coordination Committee, 1993, NSW Guidelines for Urban and Residential Use of reclaimed Water Sydney Water, 2000, Rouse Hill Recycled Water Scheme Risk Management Study Sydney Water, 2001 , Sydney Water Emergency Risk Management Policy Sydney Water, 2007, Sydney Water Corporate Risk Framework

water DECEMBER 2008 51

water reuse

[SJ

refereed pape r

RECYCLED WATER EXPOSURE: FILLING THE DATA GAPS J O'Toole, M Sinclair, K Leder Abstract This paper describes the 'Wat er usage study' conducted in metropolitan Sydney from February to April 2006. The study was undertaken to collect information about the d uration and frequency of recycled and drinking water use for nonpotable household purposes. A telephone interview was administered to a total of 1037 eligible households (half supplied with recycled water in the Rouse Hill development, half as control), about their use of water for outdoor uses, toi let flushing and machine clothes wash ing. Results are compared with freq uency exposure estimat es given in Australian Guidelines for Water Recycling.

Introduction The Austral ian Guidelines for Water Recycling (Phase 1) (AGWR) use a risk management framework which involves identifying and managing risks in a proactive way (NRMMC/EPHC/ AHMC 20 06). From a health perspective t hese g uidelines focus on microbial hazards and use the Quantitative Microbial Risk Assessment (QMRA) process for guideline setting. Exposure assessment, a constituent step of QMRA, requires data that describe the intensity, frequency and duration of exposure (Haas and Rose 1996). Estimates of exposure volumes and frequencies per person for garden irrigation, toilet flushing and washing machine use are provided in the AWRG (Box 1) and it is suggested t hat these values, considered to be conservative, could be used as defaults where specific or local information is not available (N RM MC/ EPHC/AHMC 2006).

This study was undertaken by the Department of Epidemiology and Preventive Medicine, Monash University, a partner in the CRC for Wat er Quality an d Treatment.

It was designed to collect local information about the duration and freq uency of recycled and drinking water use for non-potable household purposes.

Whilst the primary focus of the study was t o obtain information about use of recycled water for non-potable

52 DECEMBER 2008 water

household uses, a secondary objective was to compare water usage of households receiving both recycled and drinking water with those supplied with drinking water only. This information is useful as it provides a measure of the impact of outdoor water restrictions on household use and allows assessment of the utility of information collected from households supplied with conventional wat er supplies for exposure estimation for households receiving both recycled and drinking water. This paper summarises the results of a computer assisted telephone interview (CATI) administered over the period February to April 2006 (inclusive) to a total of 1037 eligible households in metropolitan Sydney. Only demographic, garden irrigation, toi let flushing and washing machine usage module results are presented in detail here. Detailed resu lts for other modules are included in a recently released CRC for Water Quality and Treatment research report (CRCWQT 2008).

Methods The study was cond ucted as a university survey and was approved by Monash University Standing Committee in Ethics and Research involving Humans.

Respondents were informed at the initial telephone contact that it was a University survey and that survey responses would be anonymous and would not be divulged to Sydney Water even if household water usage was in contravention of Level 3 d ri nking wat er restrictions.

The Rouse Hill development, northwest of Sydney, postcodes 2155 and 2768, commenced in 2001 and incorporates tertiary treatment of sewage and dual reticulation of recycled water for toilet flushing and non-potable ¡ outdoor use, as outlined in Box 2.

Data were collected from 523 households. An extensive survey of water-using behaviours had not been

Understanding the risk profile for non-potable uses.

administered to Rouse Hill dual reticulation residents before this survey.

The same CATI, with minor changes, was administered to 514 eligible 'control' households, supplied with conventional drinking water only, located in metropolitan Sydney. Control households comprised households located in the suburbs (postcode) of Harrington Park (2567), Bella Vista (2153), Glenmore Park (2745) and Cecil Hills (2171). Households in these suburbs were chosen based on similar demographic characteristics to those in the Rouse Hill dual reticulation postcodes (ABS 2001).

Water use by the control households was governed by Level 3 Restrictions as outlined in Box 3.

Household recruitment The strategy employed to select eligible dual reticu lation and control households used Australian Electoral Commission (AEC) and Electronic White Pages (EWP) records. The AEC records were used to obtain the names and addresses of eligible householders. These records were then matched with EWP records to obtain a household telephone contact number for administration of the CATI. Elect or households with a listed telephone number in the EWP were sent an introductory letter inviting them to participate in the study. Telephone contact was commenced one to three weeks after the introductory letter despatch. Four telephone contact attempts were made before contact was termi nated. The majority of telephone calls were made between 6pm and 9pm.

Computer Assisted Telephone Interview The CATI questions used for t he survey were based on previous Australian household water activity surveys (Metropolitan Water Authority 1985; Roberts 2004). As recycled water in Rouse Hill dual reticulation households is used for toi let flushing and outdoor water use, the CATI was designed to include questions about these activities. Wh ilst recycled water is not plumbed into Rouse Hill dual reticulation households for machine washi ng, the CATI was also designed to include questions relating to

echn1ca1

eatures

Cs]

water reuse

refereed paper

laundry activities. The CATI was divided into 9 modules and was of approximately 15 minutes duration. Modules included: General questions module; Garden module; Toilet module; Swimming pool module; Car washing module; Pet washing module; Hard surface clean ing module; Laundry module and 'Other' module.

Toilet flushing Table 3 summarises the reported toilet flushing frequency and ow nership of toilets in Rouse Hill and control households. These results show that the number of toi lets in Rouse Hill households was significantly greater than for control households. Results also show no significant difference between the estimated total number of toilet flushes (at home) between groups either on weekends or weekdays. Th e mean number of flushes per person for dual reticulation households was 4.4 and 5.6 for weekdays and weekend days respectively. This compared with 4.2 and 5.4 for weekdays and weekend days respectively for control households.

Statistical analysis Statistical analysis was carried out using STATA version 9 (STATAâ&#x201E;˘ Stata Corporation, Texas, USA). A nonparametric Wilcoxin rank sum (MannWhitney two sample statistic) was used to compare the household numerical estimates of water use duration and frequency. A two sample test of proportion was used to test the equality of proportions of households performing a particular activity.

Laundry module

Results Sample demographics and housing stock The average number of persons per household was 3.48 and 3.54 for control and Rouse Hill households respectively.

Statistical analysis of results showed that compared to the control population, Rouse Hill residents had significantly more child ren under 5 years old (p=0.017); more people home during weekdays (p=0.041); fewer years since establishment of the garden (p<0.001) and more taps located outside the home (p<0.001 ). Comparison of responses from each householder group showed no significant difference (p>0.05) between groups in the proportion of owneroccupier households, the type of garden and for households with a garden, the percentage of the housing block occupied by the garden (detailed data not shown).

Garden irrigation Tables 1 and 2 summarise household responses to questions about garden irrigation. Table 1 shows the numerical data and Table 2 summarises the prevalence data (proportion of households with a positive response to Yes/No questions about a particular activity). These results show that Rouse Hill households watered the garden on a significantly greater number of occasions in the 7-days prior to CATI administration compared with control households (p<0.001) and that the duration of garden watering using a hose and sprinkler was significantly greater for Rouse Hill households (p=0.006).

The method of garden watering was significantly different between groups, since the control households were subject to Level 3 restrictions.

There was a significantly higher prevalence of the use of automatic wateri ng systems (p<0.001), manual wateri ng systems (p=0.003), and hose and sprinkler (p<0.001) by Rouse Hill households. Conversely, a significantly higher proportion of control households used a hand-held hose (p<0.001) and watering cans and buckets (p<0.001).

Rouse Hill dual reticulation households predominantly used recycled water (93%) for garden irrigation, followed by a mixture of recycled and drinking water (6.5%) and then drinking water only (<1%).

Responses to wash ing machine module questions showed that there was no significant difference (p>0.05) in the estimated average number of washing machine loads per week between household groups. The mean number of weekly washing machine loads for Rouse Hill and control households was 5.2 and 5.4 respectively.

Results also showed no significant difference in the washing machine practices between groups. Rouse Hill and control households had similar proportions of front loading washing machines (13% and 17% respectively), machine water level settings, water temperature selection and laundry washing machine use. For both household groups, almost all clothes washing was undertaken in the washing machine (>95%); the high water level setting was predominantly used (>35%) and cold water was most commonly used for machine clothes wash ing (>75%).

Box 1. Excerpt from Table 3.3 Australian Guidelines for Water Recycling: Managing health and Environmental Risks (Phase 1).

Activity

Route of exposure

Volume (ml )

Frequency /person/year

Comments

Garden irrigation

Ingestion of sprays

0.1

90

Garden watering estimated to typically occur every second day during dry months (half year). Exposure to aerosols occurs during watering

Toilet flushing

Ingestion of sprays

0.01

1100

Frequency based on three uses of home toilet per day. Aerosol volumes are less than those produced by garden irrigation

Washing machine use

Ingestion of sprays

0.01

100

Assumes one member of the house is exposed.

Calculated based on ABS data. Aerosol volumes are less than those produced by garden irrigation (machines usually closed during operation)

water DECEMBER 2008 53

water reuse Outdoor water uses (excluding garden irrigation) A significantly higher proportion of control households owned swimming pools (30 %) compared with Rouse Hill households (22%). Responses to questions about the water used for filling swimming pools showed that Rouse Hill householders (N=116) predom inantly used drinking water (84%) , followed by recycled water only (13%) and then a mixture of recyc led and drinking water (3%). The proportion of households with swimming pools and filling them in the 7day period prior to the CATI did not vary statistically between groups nor did the duration of each swimming fi ll session and the number of filling sessions in the 7-day period.

A significantly higher proportion of Rouse Hill households (71 %) washed the car at home compared w ith the control group (36 %) and a significantly lower proportion of Rouse Hill households (24%) last washed the car more than four weeks ago compared w ith control households (43%). There were no significant differences in the duration of the car wash session using a hose and trigger nozzle between groups but only 7 control households versus 83 dual reticulation households used this method. The dual reticulation households used significantly fewer buckets of water per session than did control households (p<0.001) however, more than one response was able to be given hence it is likely that the lesser number of buckets used w as compensated by the use of hose and trigger nozzle. Rouse Hill householders predominantly (99%) used recycled water for washing cars.

A significantly higher proportion of Rouse Hill households (53%) washed hard surfaces outside compared with the control group (9%). Rouse Hill householders predominantly (97%) used

Q

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Box 2. Recycled water use at Rouse Hill.

Permitted uses

Uses not permitted

• Watering lawns and gardens

• Drinking

• Flushing toilets

• Cooking or kitchen purposes

• Washing cars and houses

• Personal washing such as baths, showers, bidets and hand basins

• Recreation not involving contact with water • Filling ornamental ponds

• Filling swimming pools

• Construction and industry

• Recreation involving water contact, for example playing under sprinklers

• Fire fighting

• Evaporative coolers • Irrigation of fruit trees or crops that are eaten raw or unprocessed

Box 3. Level 3 drinking water restrictions in place for household customers of Sydney Water Corporation at the time of the survey.

• Hand-held hosing and drip irrigation allowed only on Wednesdays and Sundays before 1OOOhrs and after 1600hrs • No sprinklers or other watering systems to be used at any time

• A permit from Sydney Water is required to fill new or renovated pools bigger than 10,000 litres • No hosing of hard surfaces, including vehicles at any time • No hoses or taps to be left running unattended except when filling pools or containers • Fire hoses must only be used for fire fighting purposes, not cleaning recycled water for washing of hard surfaces and a significantly lower proportion of these households used a bucket for washing outside hard surfaces (3%) compared with control households (29%).

Twelve per cent of control households reported the ownership of a rainwater tank compared to less than 1% of Rouse Hill households.

Discussion This is the first survey d irectly comparing the water-using practices of Australian dual reticulation households with households in the same metropolitan area supplied with drinking water on ly, conducted independently of the water authority responsible for provision of the water supply. Th us, this water usage study distinguishes itself from other

surveys of the water-using practices of Australian householders not only because of its focus on dual reticulation households but also because it was not conducted, or commissioned, by a water authority. This is important as this red uced any potential distortion of answers to CATI questions that may have occurred associated w ith a perception of repercussions that might arise from divulging water uses contrary to those recommended or allowed by the relevant water authority. This study also assured the anonymity of respondent households with eligible hou seholds randomised, and then contacted according to the numerical sequence of an allocated household random number.

Results showed that there were s ignificant differences in outdoor water usage practices between Rouse Hill and

Table 1. Household garden irrigation (numerical responses).

Question

Control households Mean (standard deviation)

N

Dual reticulation households Mean (standard deviation)

N

p value

No. times garden watered in last 7 days

1.66 (0.95)

251

2.25 (2.21)

357

No. people in garden when garden watered

0.26 (0.68)

235

0.28 (0.86)

344

0.815

No minutes handheld hose watering per session

30.6 (24.8)

213

26.3 (18.0%)

21 1

0.269

No. minutes automatic system operated per session

37.9 (22.7)

35.6 (29.6)

79

0.626

42.2 (37.1 )

61

0.153

<0.001

No. minutes manual system per session

80 (82.5)

7 6

No. buckets per session

4.8 (3 .9)

40

5 (3.8)

11

0.669

No. minutes sprinkler per session

10 (7.1)

4

46.8 (34.4)

70

0.006

Key: bold = significant at a = 0.05

54 DECEMBER 2008 water

N = number of respondent households

technical features

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Table 2. Household garden irrigation (prevalence).

Control

Dual reticulation

Proportion

Cl-95%

359

D.7D2

0.655-0.729

Watered garden in last 7 days

251

0.845

0.800-0.889

Handheld hose

251

0.028

0.008-0.048

Automatic fixed system

251

0.128

0.086-0.169

Manual system

251

0.163

0.118-0.209

Bucket to water garden

251

0.020

0.003-0.037

Hose and sprinkler

N

Key: bold

Variable

N

Proportion

Cl- 95%

p value

463

0.762

0.723-0.801

357

0.602

0.551-0.653

357

0.219

0.176-0.261

357

0.224

0.181 -0.267

0.051 <0.001 <0.001 0.003

357

0.034

0.015-0.052

357

0.200

0.158-0.240

<0.001 <0.001

=significant at a =0.05 N =number of respondent households

control households. This is not surprising given t hat in the case of Rouse Hill households, the amount of recycled wat er able to be used for a specific set of uses (Box 2) is unrestricted. For control households, where there is generally no alternative source of water supply for outdoor water uses (only 12% of control houses reported ownership of rainwater tanks), the drinking water rest rictions (Level 3 restrictions in place since June 2005 up to the present - Box 3) a re a primary influence on the frequency and mode of garden irrigation, car washing and the washing of outdoor hard surfaces. For example, relative to dual reticulation households, control households watered the garden significantly less frequently in t he 7-day period preceding the CATI; only 4 control households used a hose and sprinkler compared with 70 d ual reticulation households; a significantly lower proportion of control households used automatic and manual watering systems; and a significantly higher proportion of control households used a hand held hose and watering cans and buckets for garden watering {Tables 1 and 2). Fewer control households washed cars at home and cleaned hard surfaces.

CATI results also showed that despite drinking water restrictions (Box 3), it does not necessarily follow that all control households will abide by water restrictions. For example, a proportion of

control households were found to use a hose and sprinkler for garden watering (2% of 251 control households watering the garden in the 7 days prior - Table 3) and to use a hose for washing cars and hard surfaces. Similarly, a proportion of dual reticulation households with swimming pools used recycled water (16%) for fi lling them despite t his being designated as one of the uses of recycled water not permitted (Box 2).

The resu lts of this st udy do not allow any quantification of how drinking water restrictions and an awareness of current drinking water scarcity may also have moderated the use of recycled water by dual reticulation households, despite there being no restrictions on the use of recycled water. It is possib le that some dual reticulation households may have reduced their water-using activities in accord w ith drinking water restrictions .

However, overall this does not appear to be the case given the low proportion of dual reticulation households employing watering cans and buckets (3%) for garden watering and the preference of these households for methods of watering including hose and sprinkler (20%), automatic watering systems (22 %) and manual fixed watering systems (22%) {Table 2).

Results of this study, w hilst showing some differences between household groups in the freq uency, method and proportion of households performing

water-using activities, did not show any significant differences in the duration of water- using sessions with t he exception of an observed significant d ifference in the duration of garden sprinkler irrigation between household groups {Table 1).

However, use of a sprinkler for garden irrigat ion is in contravention of Level 3 drinking water restrictions and the number of control households using this method for garden irrigation was low (N = 4).

Overall, the duration of exposure appears to be somewhat standard for both household groups. The duration of a water-using task appears to depend less on drinking water restrictions and more on the necessity to perform a task for a minimum period of time (e.g. a minimum vo lume of water is required before a car is 'clean'), standardised settings (e.g. automatic timers on irri gation systems), perceived 'adequate' watering session duration by hand held hose or manual watering systems, or a tendency for people to report 'rounded numbers' . Of note is that despite t he lesser garden establishment age for dual reticulation households, a statistically significant difference in the duration of garden irrigation between household groups was not observed. This result is unexpected as garden establishment age is a determinant in the volume of water needed for garden irrigation, with older established gardens requiring less water

Table 3. Toilet flushing frequency and household toilet numbers.

Question

Control households

Dual reticulation households

p value

Mean (standard deviation)

N

Mean (standard deviation)

N

No. toilets

2.51 (1.52)

514

2.68 (1.34)

523

<0.001

No. dual flush toilets

2.43 (0.73)

511

2.60 (0.59)

520

No. total flushes weekdays per respondent

4.2 (2.2)

510

4.4 (2.3)

521

No. total flushes weekends per respondent

5.4 (2.6)

510

5.6 (2.9)

521

<0.001 0.421 0.110

Key: bold = significant at a

=0.05

N = number of respondent households

water DECEMBER 2008 55

~ r e f e r eed pape r

water reuse t han more recently established gardens.

Possible reasons for the concordance in results may be that the years of garden establishment in the dual reticulation households are over a critical threshold value or that the lesser age of the dual reticulation gardens may be compensated for by the greater frequency of watering by these households. It is also possible that the drought increased the watering frequency of control households.

Observations about duration estimates however do not apply to the frequency of exposure, nor the proportion of households exposed; factors which demonstrably differ between dual reticulation and control household groups. The frequency of exposure and the proportion of households exposed appear to be dependent upon behavioural factors and the influence of water restrictions (e.g. dual reticu lation households water more frequently than control households because they are able to, irrespective of similar local climatic cond itions). The more liberal permitt ed use of recycled water also gives rise to the acquisition and ownership of specific types of waterusing equipment. For example, dual reticulation households show an approximately tenfold higher use of automatic watering syst ems and hose with sprinklers compared with control households. The use of these methods in particular, changes the exposure profile of householders in that dual reticulation householders, in contrast to control householders, do not have to be present when such watering methods are employed.

For both the dual reticulation and control household population groups, results show that there is significant natural variability in water-using behaviour of householders and a complexity of factors influencing exposure to recycled water (and thereby water-borne contami nants). In terms of the recycled water exposure profile of dual reticulation households it is clear that the idiosyncrasies associated with recycled water supply do impact on the exposure profile of dual reticulation households that cannot be extrapolated from control household behaviour.

The AGWR (Box 1) give a frequency estimation for garden irrigation of 90 times per person per year derived from an assumption that garden watering during dry months (half year) occurs every second day (3.5 times per week).

Results of this survey show that the per

56 DECEMBER 2008 water

week estimate (mean) for household garden irrigation for dual reticulation householders was 2.25 times per week giving a total est imate of 59 wateri ng sessions per year, also assuming that gardens are watered six (dry) months of the year. This point estimate indicates that recycled water guidelines overestimate exposure, although both estimates are of the same magnitude.

Recycled water guidelines also indicate that exposure to aerosols occurs during wateri ng, but as discussed above th is will depend upon the mode of watering and is likely to be less for modes that do not require the continuous presence of the householder such as use of automatic watering systems and hose and sprinklers.

Results for the toi let usage module (Table 3) showed no significant differences in the estimates of use of the home toilet provided by both household groups despite significantly higher numbers of children under 5 years old and persons at home during weekdays in dual reticulation compared with control households. This may be accounted for by the use of nappies for under-5 year olds. Both dual reticulation and control household respondents gave an estimate of 4.3 (mean) toilet flushes per person per day at home for weekdays and increased estimates for weekends (mean 5.5). This compares with an average estimate of flush frequency of 3.7 fl ushes per capita per day obtained in a 2004 Victorian study (Roberts 2004).

The concordance of estimates for number of flushes per day for dual reticulation and control household exposure estimates indicates that information obtained from conventional water supplies about toilet fl ushing frequency may be applied to dual reticulation households. However, this does not necessarily apply to exposure volume estimates. This is because the type of toi let wi ll influence the exposure volume. In this study in both the dual reticulation and control households there was a high proportion of dual flush toilets (>98%). However, this will not always be the case. A 2003 study of households receiving a convent ional drinking water supply found 82% of households to have dual flush toilets (Roberts 2004). In addition, the volume of water used per flush in dual flush toilets has been reduced over time, hence it is likely that newer housing developments, such as those with dual reticulation schemes, have greater

penetration of 6/3 litre dual flush toilets compared to older housing developments. Such differences should be taken into account when considering the application of data gathered from conventional households to dual reticulation households for exposure volume measurement.

The AGWR (Box 1) give a frequency estimate of 1100 flushes per person per year based on three uses of home toilet per day. Based on results of this study and using an average of four uses of home toilet per weekday and five uses of home toilet per weekend day, a frequency estimate of 1600 flushes per person per year is obtained, indicating that AGWR estimations underestimate the frequency of exposure and may need some revision.

The concordance of dual reticulation and control household exposure estimates for washing machine loads also indicate that available information about indoor water usage of conventional households can be applied to dual reticulation households. The average number of weekly washing machine loads for Rouse Hill and control households of 5.2 and 5.4 respectively is similar to that obtained in a Victorian study of 5.0 loads per week (Roberts 2004). In addition, results for this st udy showed that there was no significant difference in the proportion of top loading and front loading washing machines, washing machine settings (water level and temperature) and the proportion of machine clothes washing between household groups.

The AGWR (Box 1) give a frequency estimate of 100 washing machine loads per person per year based on an average of 2.6 people per household and an estimated five washing machine loads per week. In this study there were 3.48 and 3.54 persons per household for control and dual reticulation households respectively. Using 5.3 loads per week and 3.5 persons per household, as obtained in this study and computing per person per year frequency in the same manner as in the recycled water guidelines, an estimate of 79 is obtained.

This estimate is lower than the AGWR figure and indicates that the AGWR estimate of exposure frequency is conservative.

Overall, results provide improved estimates of the distribution of recycled water use for various water-using activities, as well as the duration and frequency of water-related activities.

Results obtained in this study support

technical features

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water reuse

refereed paper

the magnitude of the frequency estimates given in the Australian Guidelines for Water Recycling: Managing Health and Environmental Risks (Phase 1) for garden irrigation, toilet flushing and washing machine use and provide additional relevant data that can be used to refine exposure estimates and for use in QMRA. However, the complexity of estimating exposure volumes must be acknowledged based on the continuing changing behaviour of households as drought conditions intensify or diminish and/ or as water usage restrictions are altered.

In addition, results of this study provide information about the utility of existing data for conventional households to appraise dual reticulation household water usage. Importantly, results showed that outdoor water usage frequency data in conventional households cannot be applied to dual reticulation households based on the unrestricted use of water outdoors by dual reticulation households. However, estimates of duration of exposure for control households may sometimes be applied to dual reticulation households given the 'standard' duration of some water-using activities for specific modes of water usage (e.g . hand held hose garden watering). Thus, in general, information about outdoor water usage must be collected specifically from dual reticulation households for exposure estimation for this household type. In contrast, results showed that data relating to indoor water usage for conventional households may be used to appraise dual reticulation household water usage and potential recycled water exposure.

However, care must be taken when such extrapolations are performed and contemporary data should be used in preference to data from earlier studies. This is because of the specific characteristics of dual reticulation households and changes in water-using appliances over time. Given that dual reticulation schemes are necessarily 'greenfield ' developments it is not surprising that they are likely to attract younger families, hence household demographics of this household type may be different from conventional households. In addition, newer housing developments such as dual reticulation schemes may differ from longer established ones based on the characteristics of household appliances (washing machine type, dual flush toilets, high pressure hose devices, automatic watering systems etc) and housing characteristics. These differences may alter exposure estimates.

The Authors Joanne O 'Toole (Joanne.O'Toole@med.monash.edu.au) has recently completed her PhD entitled 'Exposure assessment for recycled and alternative water use' and this survey was one component of her research. All authors are based at the Department of Epidemiology and Preventive Medicine, Monash University, where Martha Sinclair is a senior research fellow and Karin Leder, an infectious diseases physician, is head of the Infectious Diseases Epidemiology unit.

References ABS. (2001). "Census of Population and Housing: Socio-Economic Indexes for Areas (SEIFA), South Australia - Data Cube only, 2001" Retrieved 3 January 2008, from http://www.abs.gov.au/ AUSSTATS/ abs@.nsf/DetailsPage/2033.4.55.0012001?

Open Document.

CRCWQT (2008). Study of water usage in urban areas. Research report No. 53. Adelaide, CRCWQT. Haas, C. and Rose, J. B. (1996). Distribution of Cryptosporidium Oocysts in a Water Supply. Wat Res 30(10): 2251-2254.

Metropolitan Water Authority (1985). Domestic water use in Perth, Western Australia. Perth, Metropolitan Water Authority.

NRMMC/EPHC/AHMC (2006). National Water Quality Management Strategy-Australian Guidelines for Water Recycling: Managing Health and Environmental Risks (Phase 1), National Resource Management Ministerial Council, Environmental Protection and Heritage Council and Australian Health Ministers Conference.

Roberts, P. (2004). Yarra Valley Water 2003 Appliance Stock and Usage Patterns Survey. Melbourne, Yarra Valley Water.

• Humes™ '\NATER SOLUTIONS

Finally, exposure estimates must take into account the possibility of residents using recycled water for purposes other than those recommended. This is demonstrated by showing 16% of householders used recycled water to fill swimming pools. Non-approved uses of recycled water can potentially lead to significant health risks and may be the driver for treatment standards required in dual reticulation systems.

Conclusion In conclusion, results from this study provide data that can be used in QMRA and information that contributes to an understanding of the risk profile associated with recycled water non-potable uses. Furthermore, results support the magnitude of frequency exposure estimates given in AGWR for garden irrigation, toi let flushing and washing machine use. The study also indicates that data relating to indoor water usage for conventional households may be used to appraise dual reticulation household water usage provided consideration is given to the unique characteristics of dual reticulation households.

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water reuse

refereed paper

THE FUTURE DIRECTION FOR POTABLE REUSE I B Law Abstract Experience from existing IPR schemes and and the development of National Guidelines that define the issues that must be addressed for advanced reuse schemes lay the foundation for safe reliabl e and cost effect ive alternatives for augmenting drinking water supplies.

However, the key requirements for indirect potable reuse ensure a superior quality of water before the product is returned to the environment.

It follows that Direct Potable Reuse (DPR) which inc ludes the key elements is also a safe, reliable and costeffective method of securing water suppli es into the future, partic ularly for those large coastal c ities where there is often a substantial d istance between raw water st orage and the wastewater treatment plants. Moreover, by eliminating the pumping DPR clearly provides a less expensive and less energy intensive option for Austral ia's major cities.

Introduction This paper builds on an earlier one presented by t he author (Law, 2003) that summarised the state of advanced reuse systems and schemes at that date and identified trends for the future.

There has been increased interest in the implementation of potable reuse, particularly in those countries that have been impacted by the longrunning drought and there are currently a number of Indirect Potable Reuse (IPR) schemes either in operation or being planned/ designed in Europe, USA, Singapore and Australia. Th e first, and only, Direct Potable Reuse (DPR) scheme in the world operates in Windhoek, Namibia and has been doing so since 1968, albeit with a number of t echnology upg rades si nce then (Law, 2003).

There is, at present, an obvious preference worldwide for the Indirect Potable Reuse option, but when pum ping costs are factored in, Direct Potable Reuse may have a lower envi ronmental footprint.

58 DECEMBER 2008 water

Direct potable reuse may have lower environmental footprint than indirect potable reuse.

Reclaimed Water Quality Quality Assurance and Monitoring Techn ical literat ure abounds with research papers and full-scale operational results that confirm the ability of the technolog ies commonly used in potable reuse schemes to reduce the wide range of possible contaminants to very low levels and in many cases to below the detection limits of modern day analytical equipment. Compliance with d rinking water quality regulations can be readily proven.

For example, t he recently released Australian Guidelines for Water Recycling - Augmentation of Drinking Water Supplies promote t he concept of risk identification and management rat her than risk avoidance and note that the techno logies in use at present, and particularly t hose t hat are membrane based, will produce a reclaimed water that reduces both microbiological and chemical risk to acceptable levels - and this before release to reservoirs or aquifers and further t reatment in a water treatment plant (NRM MC & EPHC, 2007). These Guidelines also identify chemicals t hat are not listed in the Australian Drinking Water Guidelines but can be in municipal WWTP effluents and outline an approach for determining their health related guideline values.

• As judged by potable water standards, the microbial and chemical quality of water intended for IPR is generally very high even before its release into the natural environment and further drinking water treatment; • Advanced treatment processes such as reverse osmosis and advanced oxidation are highly effective barriers to recently identified chemicals of concern such as pharmaceutically active compounds, steroidal hormones and chemicals such as Nitrosodimethylamine (NOMA) and 1,4-dioxane.

Nevertheless, it is important to note that there must not be sole reliance on the technology in the Advanced Water Treatment Plant (AWTP) to reliably produce the high quality of water there are other equally important factors t hat must be built into any pot able reuse scheme, namely: • Institutional capabil ity; • Catchment management - and in particular, trade waste or source control; • Efficient wastewater treatment ahead of the AWTP • Seamless liaison and communication between WWTP & AWTP operational staff; • Operation of the entire system to an accred ited Hazard Analysis and Critical Control Plan (HACCP) - a system originating in the food industry and which assures product quality while reducing reliance on end-product testing; • Appropriate level of on-line instrumentation for continuous measurement of all ident ified Critical Control Points (CCPs);

Further, Khan & Roser (2007) concluded, in their assessment of the risks associated with IPR, t hat:

• Appropriate level of institutional capability including appropriately trained operating staff;

• Despite more t han forty years experience, no clear deleterious health effects from planned indirect potable recycling schemes have been observed;

• Appropriate level of equipment redundancy; • A t reatment t rain in the AWTP that incorporates the 'Multiple Barrier' concept;

tech n ,ca I features

water reuse

[ ] refereed paper

• On-going multi -parameter 'verification ' monitoring.

• Regular audits by panels made up of independent specialists in the various fields .

Adoption of the 'multiple barrier' approach results in there being no loss in product quality if there is reduced performance of one of the treatment bar riers and it also reduces the variability in t he quality of the reclaimed water produced.

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Institutional Capability Provision of a safe drinking wat er from a com promised raw water source or a reclaimed water is a challenging task that will generally involve 'high end ' tech nologies - exemplified by the upsurge in membrane-based water treatment and advanced water treatment plants around the world . Management of such schemes can be exacti ng and it is important that Utilities or Agencies that embark on this course of action have appropriate levels of expertise and personnel on t he staff as well as a commitment t o managing and monitoring throughout the life of the scheme.

Regu lators of such schemes must also have a matching and appropriate level of institutional capability to ensure that they have a meaningful role in ensuring that the scheme is a success.

Trade Waste (or Source) Control The effluent from a Municipal WWTP should no longer be viewed as a 'waste product' that is treated before release to safeguard the environment; it should rather be viewed as a valuable resource that with further t reatment can be used for a myriad of reuse applications. With this premise, it is of the utmost importance that a Trade Waste or Source Control Prog ramme is in place to control the quantity and nature of cont aminants that are discharged to the sewer system in order to protect the wastewater treatment plant (WWTP) and the quality of reclaimed wat er.

It follows therefore that Trade Waste or Source control is a very important first barrier in any advanced reuse scheme and particularly those that incorporate potable reuse.

The Public Utilities Board (PUB) in Singapore recognised this importance in the early planning days of NEWater and currently has a comprehensive set of regulations in place to control trade waste discharges to its sewers. These reg ulations are supported by routine

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surveillance and enforcement measures that include (Tan, 2008): • Regular surveillance of factories, and particularly those identified as potential sources of illegal discharges.

Identification of this latter group is achieved throug h analysis of licences issued for the use of certain chemicals, the MSDS of each of these chemicals and routine analysis of t rade waste effluent; • Routine checking of, and t aking of samples from, manholes at key nodes in the sewer network, and • Regular discussion with trade waste generators to educate and engage them on in-factory actions that can be taken to control or reduce their discharges.

Recognising that the most vigilant trade waste control programme cannot prevent deliberate and intermittent illegal discharges into sewers, and as the PUB's main concern is organic solvent discharges, it has installed Volatile Organic Compound (VOC) analysers at strategic locations in the sewer network such as pump stations that serve clusters of industries and at WWTP inlets. These on-line analysers are linked to a central monitoring syst em that serves as the hub of a remote voe monitoring and warni ng system. In addition, transportable voe monitoring units are used within the network and these units are complete with sampling pump such that in the event of a high vapour phase VOC being measured , a sample is taken of the liquid flow for a more detailed analysis.

An example of the effectiveness of the Remote Monitoring System is shown in Figure 1, which is a plot of VOC concentrations on the effluent discharged

from a factory that used an organic degreaser in its operations. Rinse waters that contained residual concentrations of this compound were discharged at night and were responsible for the high VOC levels. Discussions with the factory have resulted in an alternative alkali-based compound being used and more effective ' house-keeping' measures put in place.

Trade waste control programmes have been in place in Australia and elsewhere in the world for a long time but the recent move to the more advanced forms of reuse have necessitat ed many of the operating authorities or utilities reevaluating the contents and comprehensiveness of their policies.

A National Wastewater Source Management Guideline has been produced in Australia for public comment (WSAA, 2007). This document has been ordered into "5 Key Wastewat er Input Management Objectives" which cover the quality of all possible source inputs that have the potential to impact on sewage or wastewater quality. These objectives address protection of safety in sewers, infrastructure assets, treatment plants, regulatory compliance and recycling.

Canberra, the National Capital of Australia, is considering a demonstration of IPR as an element of the Water Security Programme and is developing a Source Management Plan that follows the intent of the draft National Guideline.

The output will be incorporated into a system wide risk management framework that covers not only source control but also the sewerage network as a whole, the WWTP, the AWTP , the reclaimed water pipeline to the reservoir, the

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There is now a realisation of t he importance of the WWTP in the overall reclamation scheme as not only does it reduce t he conventional parameters such as BOD, COD, Suspended Solids, Ammonia, Total N and Total P but research work overseas (Kreuzinger et al, 2004) and within Queensland, Australia (Leusch et al, 2005) has shown that act ivated sludge treatment using long Solids Retention Times (SRTs) and coupled with b io N removal achieve high levels of endocrine disrupt ing compounds (E DC) removal. The Queensland work showed t hat 'act ivated sludge treatment was very effective at rem oving EDCs from sewage' and it also noted t hat t he comparatively higher levels of EDCs reported in municipal eff luent in the UK may well be due to the fact that trickli ng filters are sti ll widely used as the form of secondary t reatment.

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The Austral ian Guidelines for Water Recycling notes t hat pharmaceuticals and nat ural hormones excreted by humans on a daily basis and compounds identified as having endocrine disrupting act ivity are generally present in low concentrations (compared t o health related values) in municipal WWTP effluents (NRMMC & EPHC, 2007) typ ical ly greater than 10 fold and in many cases greater t han 1,000 fold below the calc ulated health guideline values. This is in line w ith results from WWTPs in Queensland, Canberra and Singapore.

It is therefore important that t he performance of t he WWTP is ' protected' as it is an important treatment barrier for a wide range of chemical compounds hence the need for trade waste or source control.

Operational Monitoring 'Operational monitoring' has the aim of providing proof that the individual process units are performing as designed an d that the quality of the reclaimed water is in line with quality requirements.

This generally involves the use of on -line instrumentation that in turn is associated with Critical Control Points (CCPs) that have been determined as part of t he HACCP risk assessment and management process.

'Surrogates' for the removal of different contaminants are also monitored on-line, with some of these also serving as CCP indicators. For example, turbidity and

60 DECEMBER 2008 water

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particle counts are associated with microbial contam inants, Total Organic Carbon {TOC) is associated w ith organic chem ical contaminants and conductivity is associated with inorganic contaminants. Drewes (Drewes et al 2005 and 2008) discuss t he development of surrogates for chemical cont aminant removal during wastewater treat ment and water reclamation, noting t hat there is also a good correlation between conductivity reject ion and the removal of compounds with a molecular mass larger t han 150 g/ mole (e.g . caffeine).

Currently t he most useful of the surrogate parameters for chemical contaminants - and o ne that is used extensively on the NEWater Plants in Singapore - is the Total Organic Carbon {TOC). On-line measurement of this parameter to the 'ppb' level in the RO permeate has shown it to be a reliable and useful su rrogate not only for AWTP performance, and t he RO system in particular, but also for identifying subtle changes in feedwater quality from the upstream WWTP. 'Action' and 'Shutdown' TOC levels in t he permeate are 95 and 150 ppb respectively and the on- line instrument values are generally in the 60-80 ppb range.

In addition, and as part of the Sampling & Monitoring Programme (SAMP), samples are taken and analysed for TOC in t he Product Water (i.e.

NEWater) Storage Tank. The variation in the TOC values from t hree of the NEWater Plants over t he period August

2003 to December 2007 is summarised in Figure 2, showing an average value of some 0.1 mg/L.

Verification Monitoring Water quality t esting is an important adjunct to any IPR scheme as it enables the proponent to show t hat the water produced complies with relevant q uality standards that are promu lgated by various agencies. This is often referred to as "Verification Monitoring". For example, the quality data produced in Singapore is used to show t hat NEWater is of a higher quality than t hat outlined in the US EPA and WHO Guidelines. The data is also used to show t hat NEWater is of a higher quality than t he normal drinking water distributed on the island.

The monitoring in IPR schemes is usually more extensive than that required for conventional water supply schemes on account of reg ulatory requirements, different raw water source and/or satisfying commu nity perceptions and concerns.

The verification Sampling & Monitoring Programme (SAMP) in Singapore covers a total of 292 different parameters that are monitored for in t he Feedwater and NEWater prod uct at each of the NEWater Factories as part of the NEWater Sampling & Monitoring Programme (SAMP), made up as follows: â&#x20AC;˘ Physical Characteristics (9) â&#x20AC;˘ Inorganic Chemical Agent & Disinfection By-Products (6)

technical features

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water reuse

refereed paper

• Other Inorganic Chemicals (44)

Table 1. Chemical Contaminant Listing.

• Organic Disinfection By-Product (26) 2,4-dintroltoluene 2,6-dintrotoluene Acetochlor Nitrobenzene 1,2-diphenylhydrazine Naphthalene Diazinon Disulfoton Fonofos Terbufos 4,4-DDE Ethylene Glycol N-Nitrosodiethylamine EPTC Prometon

• Other Organic Compounds (36) • Organic Indicators (7) • Pesticides (57) • Rad iological Quality (6) • Wastewater 'Signature' Compounds (4) • Synt hetic and Natural Hormones (4) • Persistent Organic Pollutants (27) • Chemical Contaminants Lists (49 parameters) • Microbiological (17) This list covers the groups of chemicals that are often raised as a 'concern' in any IPR scheme. For example, the Chemical Contaminants List - which is essentially a 'parking lot' for emerging chemicals of concern currently includes the chemicals listed in Table 1, many of which are reported Endocrine Disruptors and others are Pharmaceutically Active Compounds.

This list of compounds was compiled from the US EPA CCL Listing, the California Department of Health Services, publications on 'emerging contaminants' and recommendations of the Internal and External audit panels.This list has recently been extended to include for t he measurement of Perfluorooctane Sulphonate (PFOS) and Perfluorooctanoic Acid (PFOA) in NEWat er.

Terbacil 2-Methyl-Phenol 2,4-dinitrophenol Diuron Linuron n-Butylbenzene Sec-Butylbenzene Tert-Butylbenzene 2-Chlorotoluene 4-Chlorotoluene Dichlorodifluoromethane lsopropylbenzene n-Propylbenzene 1,2,4-Trimethylbenzene 1,3,5-Trimethylbenzene Carbon Disulphide

ROX Phenol

Water Project has recently been carried out as part of the overall project Recycled Water Management Plan (Roux et al, 2008) and the find ings of this study were used to formulate the initial Verification Monitoring Programme for the product water (referred to as 'purified recycled water').

Indirect vs Direct Potable Reuse The significant difference between a Planned Indirect Potable Reuse (PIPR) and a Direct Potable Reuse (DPR) scheme is that in the former the reclaimed water is discharged into an environmental buffer - be it a groundwater aquifer or a form of surface water - where it is mixed with a raw fresh water prior to being further treated in a water treatment plant before distribution

A comprehensive assessment of the feedwater quality for the AWTPs that constitute the Western Corridor Recycled

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Figure 3. Comparison of Operating Costs for the supply of 100 ML/d of Water to a Coastal City.

to the consumers. The level of treatment afforded at the AWTP and the quality of reclaimed water produced wi ll generally be the same in both options.

Given the qualities of reclaimed water being achieved around the world, the necessity for the environmental buffer, particularly surface storage, and the subsequent additional treatment is questioned. The reasons often put forward for the inclusion of the environmental buffer - die- off of microorganisms, UV degradation of intractable organics to name but a few are of little to no relevance to the very high quality of water produced - rel iably - at the AWTP. Further, discarding the 'environmental buffer' by adopting the DPR route will defuse concerns that are often raised over possible impacts that additional nutrient loads in t he reclaimed water might have on the surface st orage reservoir. As an aside, it is noted that in some cases the discharge of rec laimed water to a surface reservoir can be of benefit to the overall water quality - a case in point is the Occoquan Reservoir that is associated with the Upper Occoquan Sewerage Authority (UOSA) scheme in north Virgin ia, USA (Virginia Tech College of Engineering, 2005) .

Excl uding the environmental buffer also sends a message t o the commun ity that the AWTP produces the quality of water required and that there is no reason for this water to then be blended into a raw water that invariably is of inferior quality to that of the reclaimed water before being treated again - often in a conventional water treatment plant that has little propensity to remove 'chemicals of concern'.

water DECEMBER 2008

61

water reuse Implications for Large Coastal Cities Many large coastal cities are currentry developing strategies for securing water supplies into the future and invariably they consider seawater desalination and IPR - after all the other, smaller return options, have been evaluated such as dual pipe systems. Recent examples of this can be found at Perth, Sydney and Melbourne in Australia where seawater desalination plants are respectively operational, under construction and in the planning phase.

A report recently released in Australia develops a hypothetical case study for a coastal city that requires an additional 100 MUd of water to meet its water capacity shortfall (National Water Commission, 2007). This shortfall could be met by seawater desalination, IPR or purchasing the water from irrigators and Figure 3 provides indicative cost information for the three schemes, with the 'cost of water' being both capital and operating and includ ing for 'treatment' and 'transport'. The chart indicates that purchase of irrigation water is the most expensive (as by implication, it would have to be transported over great distances) and that IPR and seawater desalination have similar total costs if the 'transport' costs are included along with the 'treatment' costs.

DPR, that is not addressed in the report, will have the same treatment cost as IPR but it does not accrue the significant transport and pumping costs associated with the IPR option (due to the fact that the storage is generally a distance away from the coast while the wastewater treatment plants are located near the coast) and this wi ll result in a scheme that, using the data in NWC (2007), is very much more cost

water Future Features FEBRUARY - On-site treatment, pressure sewerage, biosolids, international sanitation MARCH - Recycling , stormwater MAY - Ozwater 09 report , membranes/desalination, climate change

JUNE - Pumping & pipelines , industrial waste

62 DECEMBER 2008 water

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refereed paper

Table 2. Comparison of Water Supply Options Supply Option

Transport Distance (km)

Cost of Water (AUO$/ML)

IPR

100

1,300

1.9

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20

1,400

4.3

DPR

20

800

1.5

effective than both desalination and IPR (by 40-50%) and one that will also have the smallest environmental footprint of all - as is shown in Table 2.

This option will also maximise the use of existing infrastructure.

Interaction with the Community The mention of Potable Reuse often raises a stir in the ranks of water professionals as well as the community at large. Much has been writt en on th e importance of avoiding 'negative branding ', the use of appropriate terminology and the development of trust between Authority or Utility and the community at large. It is of interest to note that the Wat erReuse Foundation is presently commissioning an initiative that addresses the terminology to be used in the water industry as a whole - and not just in advanced reuse applications.

A recent survey of community attitudes to water recycling in the major cities of Australia showed that providing information, in the form of a leaflet, to the commun ity did result in a small increase in the acceptance of recycled water (Roseth, 2008). Further, it was shown that the form of ' information sharing ' would have to be more than a leaflet if a more marked shift towards the use of recycled water is to occur.

This 'finding' on the importance of information sharing is not 'new' and it is disturbing that there has not been more action to address this major deficiency - rather than conducting further surveys to find the same result.

There are examples of successful outreach programmes that include significant information sharing; the two most significant being that for the Groundwater Replenishment Schem e (GWRS) in Orange County, USA and that associated with NEWater in Singapore.

The programme in Singapore is based around a Visitor Centre that uses state- of-the-art interactive computer screens and videos to promote a more holistic understanding of water issues.

There is the opportunity for the visitor to hear, read and watch explanations of

Energy Usage (kWh/kl)

water quality and treatment and by promoting understanding of the full spectrum of water supply solutions, to understand that reuse is an important solution - all at his or her own pac e.

Further the Visitor Centre is built around an operational NEWater Plant tech nology and education have thus been merged in one facil ity and visitors can see a full-scale plant in operation as part of their Visitor Centre experience.

A measure of the success of the Visitor Centre is that some 574,000 people have visited since it was officially opened in February 2003, of this total , 50 % are school children, 25% from the local Singapore community and 25% from overseas (PUB, 2008).

Plans to develop such Centres in Austral ia are now well advanced - at the Gippsland Water Factory in Victoria, in Canberra and at the proposed Centre of Excellence in Brisbane.

It is considered that commu nity surveys have now run their course and that we should be concentrating on more innovative approac hes to providing information to the community that stimulate and promote their considered input t o the development of future water supply solutions.

Conclusions It is concluded that sufficient experience has now been gained into the operational performance and reliability of AWTPs associated with Potable Reuse schemes around the world to show that the Indirect Pot able Reuse route, with its environmental buffer and further treat ment, is not necessary and that Direct Potable Reuse is a viable option. Th is conclusion wil l be of particular relevance to large coastal cities which are currently investigating means of securing water supply into the future and are concerned about the environmental footpri nt of their preferred solution, a particularly relevant factor in the current cl imate change and carbon trading discussions that are occurring in Australia.

technical features

water reuse

~ refereed paper

H owever, we must not forget that there are a number of peripheral factors t hat must be con sidered in developing any potable reuse scheme.

Community interact ion and education must also be an int egral component of any such scheme and the provision of an a ppropriate level of information is of paramount importance.

Closure "Never d oub t that a small group of thoughtful, committed citizens can change the world. In deed, it's the only thing that ever has" - Margaret Mead, distinguished anthropologist, intellectual and scientist.

The Author Ian Law is Principa l of IBL Solutions & Adjunct Professor, University of Queensland, (email: ib law@bigpond.com) , P O Box 226, Wellington N SW 2820, Australia.

References Drewes J. E. , Bellona C., Oedekoven M., Xu P., Kim T.U. and Amy G. (2005). Rejection of wastewater-derived micropollutants in high pressure membrane applications leading to indirect potable reuse.

Environmental Progress. 24(4), 400-409.

Drewes J . E. , Sedlak D., Snyder S. and Dickenson E. (2008). Development of Indicators and Surrogates for Chemical Contaminant Removal during Wastewater Treatment and Reclamation. Report in Preparation, WaterReuse Foundation.

(2007). Australian Guidelines for Water Recycling: Managing Health and Environmental Risk (Phase 2) Augmentation of Drinking Water Supplies (Draft for Public Comment). ISBN 1 921173 20 3.

Foley J., Batstone D. and Keller J. (2007). The Challenges of Water Recycling - Technical and Environmental Horizons. Advanced Wastewater Management Centre

National Water Commission (2007). Using Recycled Water for Drinking - an introduction, Waterlines Occasional Paper No 2, June, prepared by GHD.

Khan S. and Roser D. (2007). Risk Assessment and Health Effects Studies of Indirect Potable Reuse Schemes. CWWT Report 2007 /01, Local Government Association of Queensland.

Roseth N. (2008). Community Views on Recycled Water - The Impact of Information. CRC for Water Quality and Treatment, Australia. Research Report No 48.

Kreuzinger N., Clara M ., Strenn 8. and Kroiss H. (2004). Relevance of the sludge retention time (SAT) as design criteria for wastewater treatment plants for the removal of endocrine disruptors and pharmaceuticals from wastewater. Water Science & Technology, 50(5), 149-1 56.

Roux A., Pirrone M., Bowen 8. and Walker T. (2008). Part 3. Water Quality Monitoring and Risk Management. Water. 35 (4), June, 75-78 .

Law I. 8. (2003). Advanced reuse - from Windhoek to Singapore and beyond.

Water. 30 (3), May, 44-50.

Leusch F.D.L., Tan 8 .L.L., Tremblay L.A. and Chapman H.F. (2005), Endocrine Disruptors in Sewage - Perception v Reality, Paper presented at AWA's OZwater Convention, Brisbane, 8-12 May. Natural Resource Management Ministerial Council (NRMMC) and Environment Protection and Heritage Council (EPHC).

Tan T. P. (2008), Personal communication.

Director Water Reclamation (Network), Public Utilities Board, Singapore.

Virginia Tech College of Engineering. (2005).

An Assessment of the Water Quality Effects of Nitrate in Reclaimed Water delivered to the Occoquan Reservoir.

Occoquan Watershed Monitoring Laboratory, Manassis, Virginia.

Water Services Association of Australia (2007). National Wastewater Source Management Guideline. Draft for Public Comment, December.

desalination

DESALTING 2008 PERTH, SEPTEMBER Report by EA (Bob) Swinton This was another excellent Specialist Conference organised by a team from AWA national office and our WA branch members, with some 152 attendees, 20 presentations, 7 poster papers and 7 exhibitors. It opened with a welcome from the Western Australians and an inspiring address from Jim Gill, CEO of the Water Corporation, who said the Kwinana desalination proj ect had been an "exciting ride" , from the day the streams "stopped flowing" ten years ago.

In that period he had had to deal with a total of eleven Water Ministers, but the Water Corporation maintained its focus.

In the original 1995 Water Futures Plan, desalination had been one of the options proposed, but was the least favoured. As the years progressed, however, it seemed increasingly clear that the 'drought' was becoming the norm, and forecasts, based on CSIRO Global Warming science, were presented to each Premier. $2M a year was eventually allocated for community education, covering both demand management and the seriousness of the situation, so that the community (and the politicians) were ready for a radical solution.

Plan was re-jigged. Two desalination companies were shortlisted, but the decision was held off for a further two years. Then in 2004 the Premier of the day had the courage to go ahead.

Community concern about energy, and the impact on Cockburn Sound, were still out there, so the decision was made to go ahead with the minimum of fuss. No visitors were allowed on site, no journalists, no politicians, not even Jim himself, until 2006, when the Premier was photographed drinking the first product. From then on it has been euphoric, with four other states joining in and their success even assisting proponents in USA.

On the international front we were honoured by keynote addresses from Tom Pankratz, Editor of the weekly international publication Water Desalination Report, and Lisa Henthorne, current President of the International Desalination Association and a Vice-President of CH2M Hill.

Tom summarised the c urrent status of desalting worldwide. Since last year, the contracted capacity has grown 24.5 per cent over 2006 by a total of 6. 7 million m 3 per day. The total contracted global desalination capacity now stands at 63.6 million m3 per day of wh ich 53.0 million m 3 per day has been commissioned. He brought to our notice Jim contrasted the political and that desalting was not just SWRO. In fact commercial scene with that of Israel, a coastal Mexico mining operation has Singapore, now Spain, and asked does recently chosen Multi-Effect Distillation Australia have to rely on international (MED) because it can cope more easily expertise, or can we develop our own? with their highly polluted seawater. West Basin LA has been reclaiming This call to arms was echoed by both wastewater by RO for potable use, Neil Palmer and John Poon, whose irrigation and seawater intrusion barrier. addresses on the status of desalination Currently they are using MF as in Australia will be published in a future pretreatment and have determined that issue of Water. tertiary filtration is not necessary. In discussion he remarked that membrane An excellent So, by 2001 , when st ream flows had treatment of urban stormwater to potable dropped to a quarter of 'normal', the Specialist Conference. quality was feasible, but dogged by inconsistency of first flush quality and the need for balancing storage. He emphasised the challenges involved in dealing with the Multiparameter Water Quality Meter concentrated brine for inland plants. In California, near-zeropH • pH/mV • ORP • % saturation DO • mg/L DO • EC liquid discharge systems are absolute EC • Resistivity• TDS • salinity• seawater being investigated for the specific gravity• atmospheric prerssure • temperature desalting of agricultural drainage water, so that it can • Display up to 12 parameters on backlit graphic LCD be recycled , but brine • Internal 12 channel GPS receiver to track locations discharge inland is virtually with measurement data impossible since the usual • GPS signal strength & co-ordinates shown on LCD technique of evaporation ponds with number of satellites is not feasible.

• Connects with GPS tracking software such as In El Paso, Texas, a 104 Google™ Maps to view locations with measured data shown on maps MUd BWRO is the largest inland desalter in the world, 03 9769 0666 drawing from a local bore field.

03 9769 0699 The 11 MUd brine is inj ected email: hannains@hannainst.com.au 1000m deep some 32 km web : www.hannainst. com.au distant from the city, at a site based on oilwell data.

Hl98280

I

64 DECEMBER 2008 water

H~NN~

instruments

technical features

desalination In Jordan, for a 130 MUd BWRO plant, the brine is released to the Dead Sea, and the product pumped up to the city, 1200 m higher. There is a proposal to pipe water from the sea down to the Dead Sea, using the hydroelectric power for an RO plant Lisa Henthorne summarised the drivers for the rapid application of large scale desalting:

• The low availability of conventional sources of fresh water and cost of developing any further extensions; • The likely impact of cl imate change on most settled areas of the developed nations; • T he incredible growth of the economy of the Middle East; • T he steadily reducing cost of reverse osmosis. However, despite the reduction in price of RO modules themselves, capex is increasing worldwide due t o scarcity of the other components.

Over recent years there have been major advances. The most significant has been the steady decrease in energy requirement, from some 11KWh/m 3 in to an optimised minimum of about 2 KWh/m3 , by means of displacement en ergy recovery devices (even so, the older Pelton wheels are still being installed), and central HP pump stations, b ut the sophisticated controls and valves necessary to feed RO units at different stages of their life still need a whole-of life analysis.

The lower cost of the large diameter modules has allowed lower flux design, whereby fouling potential is reduced for a tolerable increase in capex. Membrane performance in terms of flux and salt rejection has steadily improved, but a ch lorine tolerant membrane is sti ll not available.

A few new plants are eliminating sand and cartridge filters by straight-through pumping th rough an MF/UF bank direct into the RO modules. (Diatomaceous earth precoats are being used in some Spanish plants).

Australia has become the pioneer for indirect coupling of renewable energy with large scale desalting, and also in improved confidence in environmental monitoring and design of intake and brine outfall diffusers.

With regard to financing and contracting arrangements Lisa made the p oint that the Alliance contract s being ad opted in Austral ia were not understood

overseas, D/ B (design-build) being the common system.

In discussion, she mentioned that the WHO limit for boron may be revised from 0.5 to 1.0 g/ L for potable water, but for citrus irrigation, as practiced in Israel , even lower limits may be necessary.

The 25 year Alliance contract for operation and maintenance of the Kwinana plant was likened t o an arranged marriage by Greg Mercer of Degremont and Sjoerd Sibma of the Water Corporation, with its complications as well as advantages, and we hope that they can draft their presentation into a paper for a future issue of Water. A coach-load of delegates visited the plant after the conference, and this reporter was impressed, not so much with the huge racks of RO modules but by the sheer scale of t he pipework and civil works. Siobhan Boerlage described the fast-track construction of the SE Queensland SWRO plant at Tugun and again we hope for a full paper when it has been commissioned.

Energy aspects were discussed by Ian Cameron of ERi and Ray Wills of WA's Sustainable Energies Association, and a paper from left field by Richard Pashley of Murdoch University, published in this issue, drew attention to the effect of dissolved air on both RO and EDR. A significant feature of this conference was the emphasis on the environmental impact of SWRO. Perth now has a year's experience of brine discharge, following their extensive modelling and trials, and the results show that thei r assumptions were conservative. None-the-less, during the calm weather of Autumn 2008, the EPA required the plant to be shut down for two separate fortnights when the natural reduction of DO in Cockburn Sound fell below the agreed level of 7 mg/ L. Concern was being expressed that t he denser brine might further accentuate stratification leading to oxygen starvation of the benthic commun ity. The first year's monitoring data in the paper by Luketina and Christ ie, published in this issue, disputes this.

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water DECEMBER 2008 65

desalination Sydney Water is also conducting extensive pre-commissioning monitoring of ocean and estuarine environment, and Susan Trousdale expanded on the paper published in Water in March. The studies are requi red to continue for three years post-commissioning.

Jill Woodworth of Geotechnical Services outlined the com plex ecotoxicology laboratory bioassays which are being used for 'whole-of-effluent' testing. The brine (including the trace chemicals used for pre-treatment , antiscaling and membrane clean ing) is progressively diluted with the receiving water and tested on species indigenous to or representative of the local ecosystem. A minimum of four different taxonomic groups must be selected, usually at their most sensitive stage, such as larval development.

The short-t erm chronic effect is a better indicator than NOEC (the concentration showing no effects) and a statistical program is applied t o the laboratory resu lts.

For the Cockburn Sound discharge, the species chosen were micro-algae, macro-algae, copepods, larval mussels and larval fish . The safe dilution for 99% protection was determined as 15x, at the boundary of the mixing zone. The diffuser design, based on 45x dilution, has been proved to be conservative and wi ll be applied for the second SWRO plant near Sunbury.

For other sites, different species are selected. For example, the proposed outfall at Whyalla must protect the giant cuttlefish spawning grounds as well as the local yellowtail fishing industry. Her laboratory is full of aquarium jars co ntaining grape-sized cuttlefish embryos .

The system can be applied to any outfall, e.g. an industrial discharge t o a freshwater stream, and used for both design and subsequent monitoring.

Whereas Australia currently only has two or three large-scale seawater

66 DECEMBER 2008 wat er

desalination plants there are hundreds of smaller scale plants operating in inland locations.

Marc Fabig, of Osmoflo, summarised the history of desalination in Australia where most applications have been for industrial or outback tourist use. (The first large BWRO plant was the 33 MUd installed at Bayswater power station in 1986). There was a steady growth ti ll 2006, when 400 plants were in operation, but recently it is being considered for municipal supply. An explosive growth is predicted for the next few years, particularly for coastal locations, where it may be cheaper to run distributed plants rather than long-dist ance pipelines.

Operation, particularly maintenance, in outback sites is challenging, since, for example, adequately staffing the water plant is a minor consideration at a mine site. Their solution has been to install "Plant Connect" a sophisticated comm unicat ion system where the plant is effectively run from Osmoflo's offices. A major consideration is the complex chemistry of groundwaters, for example, high dissolved silica, often at temperatures higher than current RO membranes can tolerate, allied with the need to achieve high recovery with low volumes of waste stream.

Other papers by CSIRO and Osmoflo considered the complexities of dealing with inland salinity, and Ian Cam eron outlined progress in desalti ng Queensland's coal seam water.

Half-a-dozen poster papers which could not be fitted into the program were useful, including one from BWA, a UK company, on the development of nitrogen- and phosphorus-free, envi ronmentally friendly, scale-cont rol agents.

New contenders in the desalination industry were in evidence at the conference, with delegations from some of the five Spanish desalination companies. Spain has some 46 million

inhabitants with much the same climate as inhabited Australia. Desalination has been used in the Lazarote and Canary Islands since 1964, but in the 1990s, during a severe drought, the Government recognised the need for new water resources and encouraged the development of a local desalination industry, mainly RO, unlike the Middle East preference for distillation processes.

The first installations were for irrigation of high value crops, but in 2004 the AGUA Program was approved. It aimed to produce some 700 GUa from about 2025 new plants. Municipal users will be charged the fu ll cost of about A$1/KL but agricultural users wi ll be 'subsidised' at A$0.5/KL, t he ' psychological' limit.

Industry will be charged higher prices.

The keenness and expertise that has been developed by the AGUA program is evidenced by the tenders present ed by Spanish compan ies for Australia's proposed large-scale plants.

In closing the conference Diane listed the issues which had been discussed: • Tec hnological advances • Energy usage and carbon footprint • Concentrate disposal • Financing projects • Regulations and • The politics associated with 'selling desalination' as a cost effective, environmentally sound supplement to our water supplies.

The Conference effectively concluded wit h a final call for Australian governments, and the voters, to recognise that desalination is now part of the sustainable management of water for an increasing population in a increasingly dry climate.

The CD with the Powerpoint slides of the majority of the presenters is available from AWA Bookshop for $85. Please email bookshop@awa.asn.au

technical features

desalination

UNUSUAL PROPERTIES OF WATER: EFFECTS ON DESALINATION PROCESSES R M Pashley, M J Francis, M Rzechowicz Abstract Recent research on the fundamental properties of liquid water has been applied to demonstrate potential new improvements to the three main technologies for desalination. They have demonstrated that the so-called 'inert' at mospheric gases, oxygen and nitrogen, have a significant influence, even at their re latively low level of solubility. For example, the almost complet e removal of these dissolved gases enhances the dispersion of fine oil droplets in wat er, simply by shaking, without the need for ad ded surfactants. Even more importantly, the almost complet e degassing of liquid water significantly enhances its natural electrical conductivity. These discoveries have recently been applied to the development of ideas for the improvement of reverse osmosis and electrodialysis.

In addition, invest igations of the effect of salt on the dispersion of bubbles in water have allowed the construction of a high density air bubble column to transfer water vapour under controlled sub-boiling conditions.

Background Recent advances in our understanding of the fundamental properties of water and aqueous electrolyte solutions have significant implications for the processes by which we obtain purified water on a large scale from various sources, such as from sea water, brackish natural water an d from the treatment of industrially contaminat ed wat er.

Membrane Reverse Osmosis (RO) t echnology is the current method of choice in terms of reliability and cost for obtaining drinking quality water from sea wat er, although, world- wide, thermal/ evaporation processes are still in common use, and electrodialysis, as well as RO, is used for brackish water desalination.

The minimum work required to desalinate sea water by reverse osmosis

can be calculat ed from t he work done by applying a pressure infinit esimally higher t han the osmotic pressure and so obtain t he reversible work done, at constant temperature, to move a semi-permeable membrane an infinitesimal distance, so desalinating a very small volume of solution. Th is gives a minimum work req uired of about 3MJ per m3 of pure water. Commercial RO systems are less efficient, typically in the range of 1020MJ/m3. Also, of course, as the salt accumulates in the reject stream the osmotic pressure required also increases. Membrane methods also have high capital costs, require pre-treatment of the salty feed water and are also limited in salt concentration (both in the feed and the waste water).

Electro-dialysis has less disadvantages t han RO but still req uires fairly sophisticated equipment. It also relies on electrical work t o separate the ions via fairly expensive, but robust, ionexchange membranes.

The relatively simple process of evaporation is att ractive. The most common current commercial form of this type of thermal/evaporative process is called multi- stage flash distillation. The latent heat of vaporisation of water is about 2.3GJ per m 3 at 100°c and about 2.5GJ/m 3 at room temperature. These values are not altered much by the addition of salt. Although these values seem high, almost all of this thermal energy is, in pract ice, recycled on condensation of the water vapour, and used to heat the salt water feed , which substantially reduces the overall energy costs. Commercial thermal/ evaporative units have energy cost s typically in the range 20-200MJ/m3 but these are still commercially viable because of

These properties might assist in the development of improved and novel processes.

significantly lower capital costs and equipment replacement costs. These plants are often built close to industrial sites which produce heat as waste, to reduce energy costs still further.

Properties of Water Water has some rather unusual physical properties. In this work we ask the question: can these unusual properties be used to improve desalination processes? Several desalination processes will be considered with respect to the development of potential innovations based on applying some of these unusual properties of water.

Cavitation within reverse osmosis membranes Water cavitates much more read ily, under suction pressure, when it is saturat ed with dissolved air and is exposed to hydrophobic groups. It is actually very difficult to cavitate pure water in clean, smoot h vessel. If we make the reasonable assumption that a ¡ phase change occurs when a spherical cavity of 1 nm radius is created in wat er, then we can easily estimate the suction pressure required. The total energy (Er) of a cavity of radius r is given by the sum of the negative work done by the suction pressure (-!JP) on the cavity volume and the surface t ension work done on creating the surface of the cavity. Thus, the total cavity energy is given by:

4 Er=-nr 3 (- t.P)+4nr 2 y 3

[I ]

A diagram of the behaviour expected for water is shown in Figure 1. If we make the assumption that 1nm is the critical radius of cavity formation, i.e. when dErldr = 0, then it follows that we can estimate the critical suction pressure:

2y -M=-rc

[2]

which for pure water gives a critical suction pressure of about -1,460 atm.

water DECEMBER 2008 6 7

desalination rings. These groups can form nano-size surface regions of hydrophobicity w ithin the polymer matrix of the membrane, which could nucleate cavities in water. In addition, it is likely that different RO membranes have different levels of hydrop hobicity.

100 80

....

---~

.:,,:

60

C

40

~

·;;

"'V 20 0

~ 0 ~ -20 0.0 -40 -60 -80

Figure 1. Theoretical calculation of the energy (in kT units) required to form a spherical cavity of radius r in pure water under ideal, de-gassed conditions, in the absence of nucleation sites, with an applied suction pressure of -14OOatm.

110

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0 ::;

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100

Cl Avera~e Gasse Results

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Pure water 0.2M NaCl 0.5M NaCl 0.75M NaCl 0.818M NaCl

Figure 2. The effect of de-gassing the aqueous feed solution on the production rate of clean water, when passed through a commercial RO filtration unit, for different salt concentrations.

In most practical situations c ontaminants and real, rough surfaces faci litate t he nuc leation of cavities in water at much lower suction pressures than th is. The presenc e of dissolved gases and hydrophobic groups also substantially reduces t he cavitation pressure. For example, experimental c avitation pressures are typically about -1 atm for distilled water, saturated with air, and -200 atm for 99.98% de-gassed water (Galloway, 1954). Thus it is clear that t he de-gassing of water and salt solutions strongly inhibits cavitation.

H We have carried out an 0 H 0 N initial study of the H variation in hydrophobicity H N 0 of some typical H H 0 commercial membranes H and we have also used a H small laboratory scale commercial RO unit to Figure 3. Schematic diagram of the study t he effects of deGrotthus mechanism for electrical gassing on product flow conductivity in pure water and a rate (Rzechowicz,. proposed model for the effect of Pashley, 2007). The results dissolved nitrogen gas molecules. obtained for water wetting contact angles on typical membranes is given in Table 1. The variati on observed is consistent with heterogeneous surfaces which could offer nucleation sites. In t he RO experiments the feed solution was de-gassed using c ommercial Teflon hollow -fibre filters usi ng a vacuum to withdraw t he dissolved gases to a level of about 99.5% de-gassed. The results obtained with this system are summarised in Figure 2. These resu lt s suggest that cavitat ion does occur in RO membranes and t hat de-gassing can enhance product f low rate. Further studies are planned using a larger scale fi ltration unit. We also intend t o study the corre lation between any improvement in product flow rate with the level of hydrophobicity of the RO membrane.

The effect of de-gassing on electrodialysis The Grotthus mechanism (1805) for the electrical conductivity in pure water is based on the prin ciple t hat water molecu les in pure water conduct electri city by a sequential process of bond breakage and reformation to carry the charge of t he extra proto ns (always bonded to hydronium ions) and hydroxyl ions.

1.4 ( t/. 0.5) µ Scm·•

The high pressure differential established across the t hin surface skin layer of an RO membrane, during the reverse osmosis process, cou ld give rise to cavitation withi n the porous polymer network. This cavitatio n would have the effect of substantially reducing product flow. The polymers used in modern composite RO membranes contain hydrophobic moieties, such as saturated and unsaturated hydrocarbon

De--gas'.'!ltd d i.,1lllf'd warer, no dissolvr-d nilrogcn, oxygen or CO2 • (pH • 7.0)

O. 7-0.9 µScm· 1 ACmosphtrt tqulllbralftl distilled woter. (pll • 5. 7)

Table 1. Contact angles of water droplets measured on a range of cleaned, dried, commercial RO membranes.

Membrane Type

Average Advancing Angle!°

Filmtec SW30HR Filmtec General Electric Toray General Electric AMDGEWPT

68 DECEMBER 2008 water

27.8 67.5 59.5 75.7

Range I°

20-35 40-90 58-64 73-75

Receding Angle I°

0 0

0.07 µScm ·•

C01 rr~, nitrogtn gas 1mrgcd distilled water. (pll • 7.0)

0

0

Figure 4. Schematic diagram to describe the recently discovered effects of de-gassing on the electrical conductivity of pure water.

technical features

desalination A simple schematic diagram of this process is shown in Figure 3.

Traditionally, dissolved nitrogen and oxygen gases have been considered to be inert. In fact, nitrogen purging is used to displace dissolved carbon dioxide, which would otherwise dominate the electrical conductivity of pure water.

However, we have recently discovered (Pashley, et al, 2005) that these 'inert' dissolved atmospheric gases significantly reduce the flow of electricity in water, perhaps by forming closed clusters, which reduce the number of conducting chains of water molecules (see Figure 3).

We have discovered that the almost complete de-gassing of water substantially increases its electrical conductivity. This situation is summarised in Figure 4. Some recent studies on water and dilute electrolyte solutions (Francis, in press) are also summarised in Table 2. These remarkable results lead us to ask whether t he use of de-gassed salt solution could increase the overall efficiency of the electrodialysis (ED) process by increasing the electrical conductivity of the ion depletion layers set up within the ED process.

Considering the results obtained in Table 2, it is likely that any effect will be more significant using dilute electrolyte solutions. We plan to examine these effects in a multi-cell laboratory scale ED unit of the type illustrated in Figure 5, in w hich it is possible to separate the hydrolysis gases from the main diluent cells. This system wi ll also allow us to study the effects of solution conductivity separate from any electrode effects associated with de-gassing.

Thermal desalination using an air bubble column The water vapour content of an air bubble in equilibrium with an aqueous solution is determined entirely by the t emperature, and does not depend on w hether the water is at its boiling point (see Figure 6). For example, the vapour pressure of water in an air bubble immersed in water at 70°C is exactly the same as that in a boiling bubble created in water boiling under a reduced pressure, at the same temperature. The boiling process is difficult to control.

However, an efficient transfer to the vapour phase can be produced without boiling.

Unfortunately, the energy cost for vaporising water is very high. The Lat ent Heat of vaporisation of water at 70°C is about 2.3 GJ/m 3 . In commercial thermal/evaporation processes, almost all of this heat has to be captured during

Cartridge

K: Cation exchange m embrane A: Anion exchange membrane

Figure 5. Multi stack (6 cell) S3 Micro Acilyzer electrodialysis lab scale unit. condensation and reused to pre-heat the feed solution. In order to capture and re-use thermal wast e heat, it is important to have a well control led process. This possibility is afforded by the unusual behaviour of sea water, in preventing air bubble coalescence (Craig et al,1993a; Craig et al 1993b) because this allows us to create a high packing volume of air bubbles, which are continually colliding but are inhibited from coalescing by the presence

700

...

S1turawd water vapour density In grn.lm

1

100

..,

20

.

T.m~~tu,. d.g C

.

100

Figure 6. The amount of water vapour carried within an air bubble, at saturation, depends only on temperature and is given in the following graph.

of salt.

This is the basis for an improved process for the desalination of sea water, based on t he efficiency of vapour transfer in a contin uous, fi ne bubble colu mn in an evaporative process below the boiling point. This method employs the very high surface area of the air/ water interface afforded , naturally, by gas bubbling in salt water, such as sea water, to improve the efficiency of evaporation and transportation of water saturated vapour, to produce drinking water from sea water. This phenomenon is illustrated in Figure 7.

Flash distillation essentially uses on ly the surface of t he liq uid as the main water vapour transfer barrier and the boi ling process itself is an irregular process , hard to control. In comparison, a high density of small air bubbles flowing continuously through the salt solution, held below the boiling point, will collect vapour throughout the entire body of the salt solution in a regular, uniform process, until the saturation point at that temperature and pressure . If the sea water is heated close to its boiling point (at normal or red uced pressure), then the air bubbles entering the base of a column wil l become completely filled with water

Table 2. Conductivity measurements on a range of dilute aqueous KCI solutions under de-gassed conditions.

Concentration of KCI (M)

Literature Conductivity (11S/cm)

1x10·6 1x10·5 1x10·4 1x10·3 5x10·3 1x10·2

14.94 147 717.8 1413

Nitrogen Purged Conductivity (11S/cm)

Degassed Conductivity (avg.) (pSl cm)

Difference (pSlcm)

0.45-0.60 1.50-1.70

1.51 2.65 15.99 148.2

0.82

14.94 146.9 719 1414

720 1414.5

0.95 1.05 1.30 1.00 0.50

wat er DECEMBER 2008 69

desalination lS +-----..__

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.

.

• Pr-•-k

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Figure 7. Nitrogen bubbles formed in a water column at a frit: in pure water (left photo) and in salt solution at 0.2M NaCl (right photo), for the same flow rate.

l.e,

20

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..

·o0 ;>

Close to the normal boiling point, about 30 litres of bubbles can carry about 20ml of water vapour. This is because the vapour pressure of water increases uniformly from room temperature to 100°c, where its vapour pressure becomes equal to normal atmospheric pressure. Hence, if air was bubbled into even a laboratory sized column of heated sea water at the rate of 1 litre per sec, this would give a maximum drinking water production rate of between 50-60 litres per day.

There is yet another unusual property of water which has direct application in the bubble column method. This stems from the observations that fairly large (> 1-2mm) air bubbles in

...

Tl,CB( 1953)

M:yogl (19251

0

.,........ (1001

+

····--,; -+-+- · ·· i;t • ·· · ·· ---· ·

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~ 10

vapour, which can then be transported regularly into a condenser and collected. There is no need to let the water boil in this process. The amount of water vapour in an air bubble immersed and equilibrated with water close to its boiling point is almost identical to that in a bubble created by boiling.

·-

I

CIII eta!, l 19781

+

= =

o+...-----,.,-....,,-~--,.---.--.....- ~ - ~ ~ . + 0

~

~

~

Radius (µml

~

~

~

~

Figure 8. Summary of the experimental measurements of bubble rise rates in water. Taken from ref 11 . water, which are used in the bubble colum n method, become non-spherical and oscillate both in shape and in trajectory as they rise under gravity. This has the dual effect of limiting their rise rate (see Figure 8) and enhancing the rate at which water vapour equilibrates within the bubbles. It is remarkable that water vapour saturation within these bubbles is attained in a few tenths of a second (Leifer et al, 2000) because of these oscillations and the circulatory fluid flow induced inside the bubbles due to the shear forces generated at the surface of the bubbles. Figure 9 shows a photograph of a laboratory scale bubble col umn system which can produce distilled water quality water, of conductivity 6microS/cm, from sea water feed , at about 47mS/cm. This laboratory scale column can produce drinking water from sea water at temperatures as low as 40°C. The bubble column, non-boiling process has several potential advantages over other desalination processes. For example, a bubble column will have low capital and capital operating costs. Unlike membrane RO systems, it does not require extensive pre-filtration of the sea water feed . The bubble column actually affords a self-cleaning, flotation system. The system cou ld be operated at lower temperatures, using sustainable energy sources, such as from solar heating and wind turbines. In addition, the bubble column could be readily used with hot, waste industrial flue gases, especially for coastal plants.

It is of some interest to consider the mechanism by which salt affects bubble coalescence. Unfortunately, however, there is still no definitive explanation. The most likely explanation is that ion pairs, forced into the surface region, form aligned dipoles which create an immobile surface layer of water molecules. This causes a zero-slip fluid boundary condition, sufficient to increase film drainage times, compared with pure water. Perhaps these unexplained properties of sea water can help us to produce drinking water more efficiently using a nonboiling, thermal process.

There is another fundamental consideration in this process which can also be investigated using the bubble column method. The heat of vaporisation refers to the conversion of liquid water to molecular water vapour. As well as the potential for improving thermal control and efficiency, the novel bubble column process also opens up the opportunity to investigate a radical new approach, based on the possibility of producing

70 DECEMBER 2008 water

technical features

desalination purified water using lower energy, water clusters to transfer water across the vapou r phase. Clusters of, say, 5-10 water molecules, will be of much lower energy than sing le water molecules and could reduce the overall energy cost significantly. Water molecules only have two strong bonds with their neighbours, within the liquid form ( Wernet et al, 2004) and these bonds could be mostly retained in a vapour phase cluster.

Clusters cont aining Na+ or Cl- ions will be of much higher energy because of the Born energy and hence will only be present in the vapour at low levels. [Note that in sea water there are 55 water molecules per ion.] Although the heat of condensat ion should still be collected and re-used, vaporisation through water cl usters offers the possibility of a substantial improvement in the overall thermal efficiency of the desalination process. The bubble column method is well suited to foster the formation of water clusters in the vapour phase and so the process could be adapted to benefit from this substant ial red uction in energy demand.

The Authors Professor Richard Pashley, r.pashley@murdoch.edu.au, is an ARC Professorial Fellow at Murdoch University, Perth. Dr Mathew Francis is a postdoctoral research fellow at Murdoch University and Miles Rzechowicz is a PhD scholar at Murdoch University. They are all members of the Division of Research and Development.

References Craig V S J , Ninham B W, Pashley RM (1993a). Nature, 364, 317-319 Craig VS J, Ninham B W, Pashley RM, (1993b). J. Phys. Chem. 97, 10192-10197 Francis M J. J. Phys.Chem. (in press) Galloway W J (1954) J. Acoust. Soc. Am. 26, 849,

Figure 9. Photograph of a laboratory scale bubble column designed to produce water of 'distilled water' quality from sea water in a single step process, without boiling.

Klein RA (2006) NIC Symposium, v32, 65-74 Leifer I, Patro R K, Bowyer P (2000) J. Atmos. Oceanic Tech. 17, 1392 Miller J E, (2003) Sandia National Laboratories, SAND 2003-0800

water and salt solutions still present significant theoretical challenges. A better understanding of these unusual properties might assist in the development of novel and improved desalination processes in reverse osmosis membrane desalination, electrodialyisis and thermal desalination.

Pashley R M, Rzechowicz M, Pashley L R, Francis M J (2005). J. Phys. Chem. B. 109(3); 1231-1238

We plan t o study the effects of mixed gases, such as air mixed with other, low Rzechowicz M, Pashley R M. (2007). J. molecular weig ht, clathrate-forming Membrane Science 295, 102-107, gases such as propane, CHCIF2 , Taylor C E, Link D D, English. (2007). J. methane and carbon dioxide (Taylor et al, Petroleum Sci & Eng 56, 186-191 2007: Klein. , 2006): Miller, 2003). These Wernet P et al. (2004). Science, 304 (5673), additives will partially dissolve in the salt 995-999 so lution and wil l equilibrate with the free gas in the bubbles.

These clathrate-forming gases might facilitate the vapour phase transfer of water clusters in the turbulent bubble column separator. Process optimisation can be readily carried out by varying the feed gas composition and type of gas The ideal filter medium mixture and monitoring the energy demand of the vapour 100% Australia owned and manufactured transfer process. Once the gas • high surface area for bacterial production and vapou r leaves the top of • encourages excellent biological film the bubble column, the water growth vapour can be condensed and • modular design for easy maintenance separated from the gas mixt ure, and handling which can then be recycled into • cost effective, efficient, reliable • chemically inert the bubble column, in a • used in trickle filters, aeration and continuous cycle. Again, the degassing systems, submerged filtration heat generated by the and treatment systems condensat ion process must be • perfect for all aqua cu ltural environments collected and reused to • ideal as gutter guard, cooling tower fill pack and in oil separation units maintai n a thermally efficient

BIO MESH TUBING

process.

Conclusions Some of the fundamental physical properties of liquid

Acacia Filtration Systems Pty Ltd Tel: 02 9756 6077 Fax: 02 9756 0173 sales@acaciaproducts.com.au www.acaciaproducts.com.au

water

DECEMBER 2008 71

desalination

MONITORING OF THE PERTH SWRO BRINE OUTFALL D Luketina, S Christie Abstract

t he Stirling and Callista Channels, however by the time it enters the deeper basin of Cockburn Sound it is extremely diluted , and cannot be traced in the deeper basins of the Sound (Figure 1).

Table 1. Recommended Dilution factors to protect susceptible biota.

The 45 GUa Perth Seawater Desalination Plant (PSDP) is sited Wet Testing • PSOP in the industrial town of Kwinana, Species Protection Level Protection Value % Brine Dilution Factor 20 km south of Perth, adjacent to 6.64 15.1 99 a gas t urbine power plant and 12.3 other heavy industries. It is built 95 8.15 In the event, the actual on the shores of Cockburn 90 9.23 10.8 diffusers themselves, after a year Sound, and during the 80 10.93 9.2 of operation, are heavily environmental approval process, populated by marine growth, discharge of the concentrated Whole Effluent Toxicity mussels and surrounded by feeding brine was raised as an area of concern Geotechnical Services Pty Ltd were fish. by the Department of Environment and engaged to assess the toxicity impact Conservation, the hypothesis being that Stratification of the brine on a number of biota, both it could exacerbate the naturally 1 free-swimming and sessile.

Table occurring stratification, and cause A concern had been expressed that summarises the outcome, expressed as under certain meteorological oxygen depletion in the deep basin of the degrees of dilution necessary to conditions, the brine, despite t he mixing the Sound. protect the most susceptible species at engendered by the vertical jetting from Consequently extensive modelling varying levels. The dilution factors the diffusers, could form a higher and real-time monitoring, before and required are all well within the 45 times density plume which could flow over a after the start-up of the plant, was actual dilution being achieved by the seabed ridge into a deep basin, and undertaken. The studies summarised in diffuser. interfere with the mixing generated by this paper have shown that there is no and wave motion, leading to wind The dispersion models were verified discernible effect beyond the mixing depletion of oxygen levels in the by the Centre for Water Research at the zone. Nonetheless, in its first year of benthic region. (Figure 2).

University of Western Australia by operation the plant was shut down by undertaking a rhodamine dye dispersion the Department, on a precautionary tests and proved to be conservative. basis, for two, two-week periods during Rhodamine dye was injected into the the Autumn calms. brine outfall and traced throughout The Outfall Cockburn Sound. The results showed that the brine can be traced out through At ful l operation, at its design performance of approximately 43% recovery, the PSDP discharges up to 200 MUd of brine at an average TDS of 66,000mg/L, compared to the average seawater intake TDS of 37,500mg/L. It is fully oxygenated by a drop structure before being discharged. The outfall was designed to achieve more than 45 times dilution at the edge of the defined mixing zone which is 50 m wide. After dispersion modelling, it was designed as a 1.6m diameter pipe running 500 m offshore, under the seabed. The terminal diffuser consists of 40 ports along the final 200 m, at about 0.5m from the seabed surface on a 60 degree angle.

This paper has been developed from the presentation to Desalting 08, Perth, September.

72 DECEMBER 2008 water

No discernible effect on DO levels in the deeper basin.

-

~-~

Figure 1. Rhodamine dispersion from a diffuser port.

Cockburn Sound High Protection

Moder•t• ProtccUon

Mixing

Zone

For Field

Br0,1der Cockburn Sound

.....

,,.,.,.,..t,s~tl\aN~.._.."..,_.,._. .. ~ p e N ~ f t c , o ~ - -

••tw~-...---u,,,.:..,c,.ot...... C.-""""~1',,.,.4.,,,._...,..,_,_~ N-..•.,;,,-..i:,t1t._~Jl"DC.~•.-.C..O~~s..,,,c(

Figure 2. Diagrammatic representation of possible brine flow.

technical features

desalination Stratification is a normal occurrence in the Sound, particularly during Autumn, when long periods of calm occur.

-~

. ,.,-., ! '

t11"41 ... [

the Swan River, demonstrating that the surface layer would rapidly become incorporated.

,,

The Southern Seawater Desalination Project

COCKDURN

IO'l'll4Cttmw.:o

Monitoring

The Water Corporation is about t o embark on its second desalination plant following the proven success of the first plant. It will initially be \ •"• N• constructed for a 50GUa plant .. . · :· ~lf'ffl ~~ ·' f ,· with the option of expanding to _ _, ", . / 100GUa in coming years. l- ~ s o v ~ o Environmental impact assessments are being performed for this second major project to be constructed at Binningup, some 200 km south of Perth, behin d a beach facing the open Indian Ocean. The outfall will run out on a gently T hese were com plemented llf,tJlf!Kl sloping seabed with no by wind data collected by the depressions, and will be Bureau of Meteorology. Figure subjected to very intense wave 3 shows the geographical action. Thus the conditions for • ......... . _..... a.., locations in relation to the [l flNIOIN•.,__,. dispersion are far more • '-"'-',....,.....~u.,ccl,:)W outfall. favourable than in Cockburn H owever, in these relatively Sound. None-the-less, a fu ll ~T'IAt flC:l.:no1HC>O:o01.'l'CDOlYOOtt.0•roA1NOLOCA'"OC warm waters, bio-fouling of the assessment is being made.

360 \YATER DUALITY IIONITORIIIO STATIONS FOR COCKBURII SOUND ........ _...,. sensors rapidly commenced.

Since the ocean conditions are _,...., "' highly dangerous for small The manufacturers, Seabird Figure 3. Map of Cockburn Sound showing monitoring boats, monitoring and sample Electronics Inc ., were brought locations. collection have been made using in and two simple modifications a remote-controlled 'Sea Glider' have greatly reduced the (Figure 6) which incorporates Sound, has proven that the PSDP does problem. Al l transparent tubing was GPS location at the times of not have an impact on dissolved replaced by black tubing and all measurements. oxygen levels in the deeper basin . This exposed met al was replaced by Dissolved oxygen levels have been also verifies all of the modelling results copper. (Figures 4, 5). measured as being relatively high, undertaken to date. The PSDP is not showing that the discharge location is Results causing or prolonging th is natural already a well mixed environment. phenomena.

The ongoing dissolved oxygen In occasional calm conditions, dye monitoring has proven that Cockburn The modelling process has also been release experiments have been Sound stratifies naturally, especially"'in applied to predict abnormal events, for performed similar to that at Cockburn the Autumn months March through to example the effect of a major flood of Sound, which have again shown the May, causing dissolved oxygen levels freshwater flowing into the ocean from area to be an extremely well mixed to d rop. The fact that the brine plume environment. from the PSDP can be traced in the In consequence, a strict monitoring program was instituted. Three purpose built buoys were deployed at 3 separate locations in the Sound, transmitting real-time dat a every 30 minutes t o the Water Corporation control room, reg istering DO, salinity and temperature at various depths. The concern was with the DO levels at 0.5m from the seabed floor.

~

, ·.

,,.

. ...,_._._,.._ ............

--~

..

-"'--

...

The result has been that the outfall is designed to be approximately 1 km offshore and the diffusers will generate

Sound getting weaker and weaker in strength and size as it moves away from the diffuser, and cannot be traced at all in the deeper basins of Cockburn

Figure 4. A fouled sensor.

..

Continued over page

Figure 5. A reconditioned sensor.

Figure 6. Sea Glider in operation.

wat er DECEMBER 2008 73

wastewater treatment

IMPELLER SELECTION FOR WASTEWATER PUMPS M Hadavi Abstract Single-stage centrifugal pumps are the reliable workhorses of the water and wastewater industry. However, while their versatility makes these pumps the logical choice for many applications, specifying the right impeller for the job can have an important impact on how well they perform in the field. This article reviews the major types available on the market and their applicability for various scenarios.

of the impeller, blocking the flow. Sand and other abrasive materials act over time, eroding impeller vanes and degrading the efficiency of the pumps.

Impeller Options

The Problems Pumps in sewage treatment plants and other wastewater management facilities have a tough job to do. Not only do they have t o move huge volumes of wastewater, efficiently and reliably, but they must also cope with a wide variety of solids and other contaminates that find their way into the waste stream.

These can include chunks of plastic, rubber, wood or other materials; fibres (e.g. pieces of cloth or sanitary products); and sand. Solid chunks block passages or even jam the impellers. Fibrous materials can build up around the throat

Continued from previous page 1/1000 dilution at 100 m distance. The final design is still under review at the time of writing.

Conclusion Modelling led to conservative design values for the brine outfall from the Perth Seawater Desalination Plant, and these have been more than verified by monitoring during the first year of operation of the plant.

None-the-less, during the calm days of Autumn, 2008, natural stratification occurred and DO levels below that specified in the PSDP's operating licence were measured, prompting the PSDP to reduce production as specified in the licence. The levels dropped over two separate periods, the first being in April for 15 days and the second being in May for 12 days.

74 DECEMBER 2008 water

blockages or swapping out damaged components is dirty, time-consuming work. At the same time though, energy costs are a significant (and growing) part of most plant budgets, so that pumping efficiency remains an important consideration.

Figure 1. A thoroughly clogged impeller.

Operators are finding that these problems are getting more serious. Lowflow toilets and other water-efficient appliances are helping to reduce the percapita water consumption, but result in higher solids content in the remaining flow! From the operator's point of view, blockages or pump failures can cause serious and costly interruptions. Clearing

Major pump manufacturers offer a variety of impeller designs. Choosing the 'right' impeller for the job depends on having a clear understanding of t he operating environment, the nature of the waste stream and the relative strengths of the various designs. There are broadly three types of centrifugal pump impellers on the market: 1. Closed impellers, with single, double or multiple vanes;

2. Open impellers, again with one or more vanes; and

3. Specialised designs.

The features and tradeoffs of each of these are outlined below.

Closed or shrouded impeller designs

The Water Corporation hope to have the environmental licence amended to reflect the current research available which concludes that the PSD has no d iscernible effect on dissolved oxygen levels in the deeper basin.

The design for the outfall of Southern Seawater Desalination Plant is more straightforward, since, unlike Cockburn Sound, it is exposed to the open ocean, however the same amount of research and modelling is being undertaken to ensure the diffusers integrity.

The Authors David Luketina is Manager, Environment and Steve Christie is Senior Engineer - Desalination for The Water Corporation, email Steve.christie@watercorporation. com.au

Figure 2. A Closed or Shrouded Impeller.

Closed impellers offer very good energy efficiency, especially with multi-vane designs. What's also important, closed impellers still deliver good efficiency

The cost of correcting unexpected blockages can be very high.

technical features

wastewater treatment while operating under low-flow conditions or when operating with an enlarged sealing gap (due to wear).

Single vane closed impellers typically provide large clear passages, wh ich reduces the danger of blockage due to large objects in the waste stream.

Unfortunately though, closed impeller designs can be more prone to clogging due to fibres in the waste stream . Th is tends t o take place in two areas: at the leading edge of the impeller, and in the narrow gap between the outer surface of the impeller and the inner surface of the vol ute casi ng. Accumulation of fibrous waste in these areas will reduce flows or even stall t he pump.

Table 1 Closed vane

Solids (in chunks) Fibrous solids Sand and abrasive solids

Specialised designs

Figure 4. A free-flow or vortex type impeller.

There are several open impeller designs on t he market that promise greatlyred uced sensitivity to clogging with fibres, thanks to specially contoured leading edge shapes and the elimination of the troublesome gap between the impeller shroud and the vol ute casi ng.

These impellers typically have generous clear passages, so that they can pass reasonably large ch unks of solid materials without blocking. The principal disadvantage of this type of impeller is t hat their p umping efficiency is lower than the best closed-vane designs, especially under low flow conditions.

These types of impeller are also less than ideal when pumping wastewater w ith significant sand content, since erosion of the vane(s) will increase tip clearances and reduce pumping efficiency.

The single vane design and swept leading edge combine to provide excellent protection against blockage by solid chunks and fibrous materials. This impeller provides a good comprom ise between anti-clogging properties and hydraulic efficiency and is capable of handling viscous sludge.

Free-flow (vortex)

Pumping efficiency

Open impeller designs

Figure 3. A single-vane, open type of impeller for high-fibre wastewater.

Open vane

Several pump manufacturers offer special free-flow or vortex-type impellers. These impellers have much shorter vanes than conventional open-type impellers and work by inducing a vortex in the pump casing. Pumping action depends on the difference between the low pressure at the centre of the vortex and the relatively high pressure around the outer edge.

Because of the stubby vanes and large clearances, this type of impeller is extremely resistant to blocking or clogging. Since there is only limited contact between the impellers and the pumped fluid , these work well with waste streams that contai n significant amounts of sand or other abrasive materials. They also work well when there is gas in the fluid. The principal drawback to free-flow impellers is their relatively poor pumping efficiency. These designs typically have efficiencies in the 40 to 50% range, compared to 75 to 80% efficiency for the closed-vane impellers Some pump manufacturers also offer so-called cutter impellers. These have special blades or shearing elements that are designed to cut long fibrous objects (sticks, pieces of cloth etc.) into smaller pieces. These impellers are optimised for specific types of solid debris and, as with the free-flow impellers, pumping efficiency may be compromised.

And the winner is ...

What 's the best pump/impeller combination for your application? The answer is, of course, "it depends". The recommended approach here is to consider the fu ll life-cycle cost of the pump inst allation. Different impeller designs typically don't change the purchase price of the pumps very much, so initial cost is not a major co ncern.

However, the cost of energy to drive the pumps can be a significant part of the equation, and here the superior pumping efficiency of closed-vane designs makes them a good choice - at least when fibrous solids are not a significant concern. As the quality of the waste stream deteriorates, reliability becomes the driving force. Experienced plant operators know that the cost of correcting unexpected blockages or equipment fai lures can be very high higher perhaps than the initial cost of the equipment! When fibrous solids can cause problems, the more clog-resistant open-vane designs emerge as a better choice. And , when things get really ugly, the so-called free-flow or vortex impellers might fill the bill.

Note that the selection of the ideal impeller type for the t oughest jobs requires a carefu l assessment of the application, especially the physical properties of the suspended solids in the waste stream. Working closely with a specialist from your pump supplier can help make sure that you get the pump/impeller combination that is best for your application.

The Author Majid Hadavi, P.Eng is National Accounts Manager, Water and Wastewater, KSB Pumps, Mississauga, Ontario.

water DECEMBER 2008 75

wastewater treatment

G

refereed paper

ACCOUNTING FOR GREENHOUSE GAS EMISSIONS IN WASTEWATER TREATMENT K Third, A Shaw, T Bridle, S Cooper The Water Corporation of Western Australia is one of Australia's largest water utilities and provides water, wastewater and drainage service to almost 2 million people across the state. In the capital city of Perth, the Water Corporation's three main wastewater treatment plants (WWTPs) at Woodman Point, Subiaco and Beenyup treat about 80% (about 340 mega litres per day) of the state's wastewater. In 2006, the W2W Alliance (W2WA) was formed to deliver upgrades to these major WWTPs over a potential 15-year, $2 billion program of capital works. The Alliance partners working with the Water Corporation on this upgrade are Black & Veatch, Thiess and Sinclair Knight Merz.

W2WA consider it essential to embed sustainability into the governance and thinking patterns of the upgrade because of its magnitude, longevity and the potential to act as a catalyst for new ideas and innovation within the Water Corporation.

An important focus of the sustainability strategy is the reduction of greenhouse gas (GHG) emissions. A comprehensive GHG model was developed to estimate all potential sources of GHG emissions from the three WWTP operations. The Excel-based model comprises five major modules, which are biotreatment, sludge processing, parasitic power draw, power credit and embodied GHG in chemicals used. The model has proven useful in quantification of the operational carbon footprint of each site and has enabled GHG mitigation efforts to be focussed in the right area.

Abstract The Greenhouse Gas (GHG) footprints of Perth's three large WWTP's - Woodman Point, Beenyup and Subiaco - were analysed under different upgrade scenarios using three different carbon accounting models. The purpose was to compare the effect of the model on the overall conclusions drawn and to see whether th e type of accounting model used determines whether a truly "sustainable" outcome is achieved. The models used were t he WSAA industry standard model, the Australian Greenhouse Office (AGO) model and a "comprehensive" model developed through t he All iance. Th e model used has a significant effect on the concl usions drawn. The AGO model accounts fo r power used on ly (scope 1 em ission), while the WSAA includes fugitive emissions from site (scope 2). These models were compared with the comprehensive model which extends the 'battery limits' to Scope 3 level, showing very different results. This paper highlights the effect of looki ng at the "bigger picture", in order to determine truly sustai nable design options in t he long term.

This paper was first present ed at Enviro08, May 2008.

76 DECEMBER 2008 water

G HGs (CO2)

Eleclricily RECs NGACs?

Gaa Engine

GHGs (CO2 and N2O)

GHGs (CO2)

GHGs (CO2, N2O, CH<)

Biogas

Fuel Treated Eftluent

Figure 1. Overview of basic elements involved in wastewater treatment.

Introduction Wastewater t reatment plants contain several unit processes that produce greenhouse emissions in varying q uantities, both directly and indirectly (Figure 1). Direct emissions include methane leaks from anaerobic digestion, nitrous oxide emissions from activated sludge basins and on-site energy prod uction (also referred to as Scope 1 emissions in t he AGO and WSAA

For truly sustainable design, look at the 'bigger picture'.

guidelines). Indirect GHG emissions are split into two further categories: Scope 2 emissions account for power pu rchased off-site, while Scope 3 em issions cover other em issions such as "embedded" carbon in chemicals purchased, emissions released during transport of chemicals and biosolids to and from site, carbon dioxide released due to biosolids mineralisation after land application and em issions d ue to employee travel. Both direct emissions (Scope 1) and indirect emissions (Scope 2 & 3) should be quantified in design project s to determine the broader impact of wast ewater treatment operations or design decisions on the environment.

technical features

wastewater treatment

~ refereed paper

Several GHG models have been developed recently to assist designers in making sustainable design choices. Prior t o the recent release of the draft National Greenhouse & Energy Reporting System (NGERS) reporting requ irement s in Australia, th e water industry standard model for accounting for GHG's in wastewater treatment is the Water Services Association of Australia (WSAA) model, which accounts for scope 1 and 2 emissions only. As with most GHG models, t he WSAA model does not account for direct emissions of CO 2 from aerobic treatment processes nor the CO2 or methane emitted through mi neralisation of the sludge at its ultimate disposal site. These emissions are considered to be part of the "natural cycle" of CO2 emissions that wou ld occur anyway if the WWTP did not exist and the wastewater entered the natural carbon cycle directly (i.e. no treatment).

Similarly, the WSAA model does not account for indirect emissions such as embodied energy in chemicals consumed.

Omission of these emissions appears to be reasonable on face value. Current industry reporting protocols consider the quantification of Scope 3 emissions as optional when preparing an overall GHG inventory. One reason for this is that one company's Scope 3 emissions are other compan ies' Scope 1 or Scope 2 emissions. If everyone were implementing the full GHG protocol, it would result in the same emissions being counted a number of times.

Nevertheless, regulatory bodies are u rging com panies to quantify thei r Scope 3 inventory as a means of developing a more comprehensive view of the global warming implications of their activities and of thei r business model generally. A Scope 3 analysis can also provide considerable insight into where companies might best focus global warming mitigation efforts. The following paper highlights the importance of including Scope 3 emissions, and Scope

Table 1. Comparison of emissions sources accounted for in the AGO, WSAA and comprehensive model.

Emission source

Model Comprehensive

WSAA

Biotreatment

X

X1

Sludge processing-biogas

X

X2

Sludge processing-trucking

X

Sludge processing-mineralisation

X

Purchased power-aeration

X

X

X

Purchased power-other

X

X

X

Chemicals used

X

CO 2 credit from power generation

X

X

X

AGO

Notes: 1 - WSAA Biotreatment calculations include N20 but not CO 2 from aeration basins 2 - WSAA Calculation is CH4 leaks only, it does not include biogas combustion 1 emissions from "natural" sources, when assessing various design scenarios for the upgrade of wastewater treatment plants. A more holistic view of emissions involved in the wastewater treatment cycle is required to take account of the fu ll impact of design choices on total GHG emissions and to make the most sustainable design decision. A case study of Wood man Point WWTP wi ll be presented, whereby design scenarios were assessed according to both the WSAA industry standard model and a "comprehensive" model that inclu des all direct and indirect emissions.

Results and Discussion Determining the baseline GHG footprint To determine the broader greenhouse gas emissions across Perth's three large metropolitan WWTP's at Beenyup, Subiaco and Woodman Point, a comprehensive greenhouse gas model was constructed (Bridle et al 2003, 2008). In comparison to the Australian Greenhouse Office (AGO) model (based on purchased power only) and the current ind ustry standard WSAA model (which includes N2 0 and methane emissions in addition to power), the comprehensive model accounts for a

number of additional GHG emission sources. An overview of the emission sources accounted for in each model is shown in Table 1.

The following emission sources are included in t he comprehensive model, but are not accounted for in t he WSAA and AGO models: • Digester biogas combustion; • Carbon dioxide emitted due to the oxidation of wastewater pollutants in aeration basins; • Carbon dioxide emitted due to mineralisation of biosolids after application to agricultural land; • Embodied energy in chemicals used.

The comprehensive model was used to establish the broader GHG footprint of each metropolitan WWTP at their cu rrent loading rates, referred to as "baseline" conditions (Figure 2). As can be seen, the current GHG footprint of Woodman Point WWTP is more than twice as large as the Beenyup WWTP, despite the fact that these plants have similar loading rates (bot h plants currently receive around 122 MUd at similar wastewater composition) and the Woodman Point plant generates power onsite using digest er gas. The large difference is due

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water DECEMBER 2008 77

wastewater treatment to the significant quantities of N2 O emitted from the aeration basins in the Woodman Point sequencing batch reactor (SBR), included under the term "biotreatment". The SBR was construct ed according to "stat e of the art" SBR technology in 2001 . The technology was considered to be more efficient due to the fact that both nitrification and denitrification could be performed in a single, low dissolved oxygen aeration phase, rather t han separating the two biological phases, as is the case at both Beenyup and Subiaco WWTP's (these plants are conventional pre-denitrification processes). Research into N20 emissions by Murdoch University in 2002 (Walker, 2002) revealed that Woodman Point emits around 15 times more N2 O from its aeration basins than both Beenyup and Subiaco WWTP's.

There is a general consensus in the literature that N20 is emitted during nitrification, when the nitrifying bacteria become "stressed", particularly under low dissolved oxygen conditions (Shiskowski, 2007). Due to the way the SBR is operated, the aeration basins subject the bacteria to low dissolved oxygen conditions , resulting in significant N2 0 emissions. It shou ld be noted that the N2 0 emission values used in the comprehensive model are based on a couple of measurements only.

Research is currently under way to more accurately quantify the N2 0 emissions and to establish the emission profiles during SBR operation.

Due to the inclusion of a broader set of emission sources in the comprehensive model, the model outcomes paint a very different pi cture to model outcomes obtained according to the AGO and WSAA models. Figure 3 compares the baseline GHG footprint of each of the three plants, according to the different models. Accord ing to the WSAA and AGO models, the carbon footprint of t he larger plants Beenyup and Woodman Point is similar, while the comprehensive model suggests a much larger carbon footprint due to the measured N2 0 emissions at Woodman Point.

It must be noted that while both the WSAA and comprehensive models both include N2 0 in the carbon accounting, the method of accounting is very different. The comprehensive model is based on actual site measurements which suggest that N20 emission are as high as 6% of the total influent nitrogen for the Woodman Point SBR, while the WSAA accounting is based on an

78 DECEMBER 2008 water

~ refereed paper

Comprehensive Model - Baseline 100,000 90,000

s

.. .

80,000

0

70,000

C C

• Chemicals used IJ Purhased power-other • Purhased power-aeration D Sludge processing-mineralisation o Sludge processing-trucking

£. 60,000 C

.S!

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40,000

1

"

• Sludge processing-biogas

30,000

IJ Biotreatment

20,000 10,000 0 Beenyup WWTP

Subiaco WWTP

Woodman Point WWTP

Figure 2. Baseline GHG footprint of Beenyup, Subiaco and Woodman Point WWTP's at current flow conditions (65 ML/d Subiaco WWTP and 125 ML/d for both Woodman Point and Beenyup), according to the comprehensive model. assumption of 1 % of the total nitrogen load. The assumption does not take into account different modes of operation of WWTP's and has the potential to significantly underestimate N20 emissions, particularly from intermittent plants that are inc reasingly known to emit significant quantities of N2 0 .

Conversely, the WSAA model may overestimate N2 0 emissions for the other facilities in the Perth area for which actual site measurements indicated on ly 0.4% of the influent nitrogen is emitted as N2 0. This highlights the importance of further research into this area. Th e fact that N20 is a potent GHG (roughly 300 times as powerful as CO2) means that it has a significant impact on the carbon footprint even when the portion of nitrogen converted to N2 0 is a fraction of a percentage point. The results of the comprehensive modelling indicate that it is necessary to more accurat ely quantify these emissions.

Assessing the GHG footprint of design scenarios After assessing the baseline carbon footprint of the wastewater treatment plants, the different models were used to assess different design scenarios for the upgrade of the WWTP's. Th is paper focuses on Woodman Point as a case study. Woodman Point currently receives an inflow of 122 MUd and its secondary treatment process is designed for 160 MUd. The plant is currently undergoing a number of upgrades, mainly to the sludge processing and odour co ntrol facilities, to ensure that the plant can continue to meet its comp liance requirements at a flow of 160 MUd. One of the design options to improve plant performance was to include ferric chloride dosing into the primary sedimentation tanks (PST's), to increase suspended solids and BOD removal, referred to commonly as Chemically Assisted Sedimentation (GAS). The intent

Model Comparison - Baseline 180,000 , - - - - - - - - - - - - - - - - - - - - - - - , 160,000 140,000 ~

[

120,000

§

100,000

(.)

i::

80,000 • Beenyup WWTP

C C

~

60,000 40,000 20,000 0 Comprehensive Model

WSAA

AGO (Power Only)

Model

Figure 3. Comparison of the carbon footprint obtained of the metropolitan WWTP's according to the different accounting models.

technical features

wastewater treatment

~ refereed paper

with CAS dosing is to relieve the load on secondary treatment by removing an increased fraction of t he load during primary treatment, thereby reducing the aeration demand on the blowers.

The models were used to assess the carbon footprint under the following three conditions: • Baseline: based on current flow and load conditions; • Ultimate design: based on the predicted flow and load conditions at the ultimate design capacity of 160 MUd; • CAS alternative: based on the flow and load conditions at 160 MUd (i.e. ultimate capacity) , with the inclusion of ferric dosing into the PST's.

The following assumptions were included in the modelling: 1. It was assumed that the nitrous oxide emissions wi ll be reduced throug h operat ional changes and reduced t o levels similar to Subiaco and Beenyup by the time the plant reaches its ultimat e capacity (this is the reason for the decreased GHG footprint in the comprehensive model between baseline conditions and ultimate conditions);

2. CAS dosing in the primary tanks will remove 85% suspended solids, com pared to only 60% without CAS dosing; 3. Ferric ch loride will be dosed at a rate of 30 mg/ L. The model outcomes under each of the different scenarios are shown in Table 2 and Figure 4. Under the CAS dosing scenario, all three models predict a significant decrease in the purchased power requirement due to the decreased blower demand in the SBR, increased biogas production and subsequent energy generated. However, in t he comprehensive model, the GHG reduction achieved by the increased biogas production is offset by an equal increase in CO2 emission due to increased sludge processing req uirements. So while the AGO and WSAA models suggest a significant positive impact can be made through CAS dosing, the comprehensive model suggests this improvement is minor. In light of these findings, it was decided that continuous CAS dosing is not worth the additional capital investment, for such a small carbon red uction, however it may be retained for occasional use for odour control and to relieve downstream processes during maintenance periods.

Table 2. Overview of model outcomes according to the different accounting models and design scenarios.

GHG Emission Source

Baseline 120 ML/d tonnes/yr

Ultimate design 160 ML/d tonnes/yr

CAS dosing alternative 160 ML/d Tonnes/yr

97,400 59,500 13,000 300 9,300 22,600 8,700 5,800 14,500 800 14,400

55,600 15,600 18,500

50,200 12,000 21,700

400 11 ,200 30,100 5,000 2,900 7,900 2,000 23,200

500 13,400 35,600 500 300 800 1,800 27,300

28,400 13,000 900 14,400

26,300 17,100 1,300 7,900

18,000 15,600 1,500 800

14,400

7,900

800

Comprehensive Model

Total GHG Emissions Biotreatment (N 20 and COv Sludge processing-biogas Sludge processing-trucking Sludge processing-mineralisation Sludge processing purchased power-aeration purchased power-other Purchased power Chemicals used CO 2 credit from on-site power generation WSAA Total GHG Emissions Biotreatment (N 20 only) Sludge processing - trucking only Purchased power AGO (Power only)

Purchased power

120,000

.

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Ultimate Design

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97,000

56,000 26,000 8,000

50,000 18,000

28,000 14,000

ca WSAA D AGO Power Onl

1,000

Figure 4. GHG emissions under different design conditions according to the different accounting models.

Table 3. Comparison between model outputs and the improvement achieved at ultimate design and the design alternative (GAS dosing).

Model

Comprehensive WSAA AGO (Power Only)

Baseline tonnes/year

Ultimate Design tonnes/year

97,000 28,000 14,000

56,000 26,000 8,000

The improvements made in each design scenario are shown in Table 3. If the design options are- assessed based on power requirements only, then the AGO model suggests almost a 100%

Improvement CAS Alternative tonnes/year % tonnes/year

50,000 18,000 1,000

6,000 8,000 7,000

10% 32% 90%

reduction can be made in GHG emissions. The WSAA model includes sludge trucking requ irements in addition to power requirements, wh ich due to the increase in t rucking requirements and

water DECEMBER 2008

79

t he basel ine demand due to N,O emissions, suggest the improvement is 32 % instead of 90 % . However, when t he broadest GHG footprint is q uantified as in the comprehensive model, including all sludge processing requirements and the embodied energy in chemicals used, the model suggests the effect is minimal, at on ly 10%. It is therefore necessary to assess the broader effect of design decisions in order to determine whether the option is actually sustainable.

Alternatives for other plants In addition to invest igating t he potential impact of CAS on t he carbon footprint at Woodman Point, t he comprehensive model was used to look at options for reducing GHG emissions at the Beenyup and Subiaco p lants. The investigations showed t hat adding cogeneration to t he digestion facil ities at Beenyup should decrease GHG emissions by 15,000 ton nes/year irrespective of whichever model is used.

At Subiaco, operating t he p lant with a short sludge age could pot entially reduce power requirements - showing a significant improvement in GHG emissions using t he WSAA and AGO models - but would significantly increase sl udge product ion and hence t he emissions from sludge mineralisation. Overall , the comprehensive model showed a net slight increase in GHG emissions when running at a short sludge age.

Conclusions The examples presented in t his paper show t hat it is important to include as many emissions as possible w hen accounting for GHGs. Failure to do so paints an unrealistic picture of the true impact of steps taken to decrease emissions. In the case of Woodman Point, the use of CAS to reduce the load o nto secondary treatment appears, on face value when using the WSAA and AGO models, t o have a sig nificant impact in reducing GHGs. However, when t he broader perspective is taken using a comprehensive model, the impact is less sign ificant. Other options such as run ning at a low SRT at Subiaco show that the choice of model can give a false impression of t he supposed improvements, particularly if t he model does not include natural emissions. Still other options such as t he co-generation facility at Beenyup make sense irrespective of the model c hosen .

80 DECEMBER 2008 water

The Authors Dr Katie Third (Sinclair Knight Merz), email kthird@skm.com .au, is the Process & Sustainabi lity Team Lead within the W2W Alliance and works to ensure that sustainable outcomes are embedded into the conceptual design of t he WWTP upgrades, and carried through to implantat ion. Andy Shaw (Black & Veatch) is a senior wastewater process specialist with a strong involvement in sust ainabi lity initiatives both within the W2W Alliance and across Black & Veatch internat ionally. Susanne Cooper (Sinclair Knight Merz) is a Sustainability Proactive Leader within SKM and was the Alliance Sustainability Manager d uring t he first 12 months of the Alliance. Susanne continues to provide strong sustainability input into the All iance. Trevor Bridle (Bridle Consulting) has over 35 years experience in wastewater t reatment and reuse , bio-solids management, renewable energy and sustainable development in the wat er and waste sectors . Trevor was heavily involved in developing t he Excel model outli ned in this paper.

References Bridle, T.R. and Casey, T.G. , (2003).

"Greenhouse Gas and Power Credits for Various Sludge Management Options".

Proceedings, AWA Biannual Conference, Perth, Australia.

Bridle, T., Shaw, A. , Cooper, S., Yap , K.C., Third , K. and Domurad, M. (2008) "Estimation of Greenhouse Gas Emissions from Wastewater Treatment Plants" Paper submitted for consideration to the 2008 IWA World Water Congress, Vienna.

Forster, P., Ramaswamy, V., Artaxo, P., Berntsen, T., Betts, R., Fahey, D. W. , Haywood, J., Lean, J., Lowe, D. C., Myhre, G., Nganga, J., Prinn, R., Raga, G., Schulz, M. , and Van Dorland, R. (2007). Changes in Atmospheric Constituents and in Radiative Forcing. in Solomon et al. (ed). Climate Change 2007: The Physical Science Basis.

Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK. Shiskowski, D.M. (2007) "Nitrous Oxide - A Powerful Greenhouse Gas with a Wastewater Treatment Connection", Proceedings of the Water Environment Federation 80th Annual Conference, San Diego, CA, October 2007 Walker, L. (2002) Bachelor's degree thesis, Murdoch University, WA

technical features

www.kochmembrane. com, call + 1-888-677-5624 or write to info@kochmembrane.com.

KOCH SELECTED BY MANILDRA GROUP Koch Membrane Systems (KMS) has been select ed to provide modules for a membrane bioreactor system (MBR) and reverse osmosis (RO) equipment to a new production plant being inst alled in Nowra, New South Wales. The overall project, which was awarded to Tenix All iance Pty. Ltd. , will expand the Manildra Group's starch and ethanol production capacity.

"By using MBR systems in combination with reverse osmosis to recycle process water, industrial companies like the Manildra Group can cut wastewater disposal costs and reduce consumption of fresh water," said lmran Jaferey, business development director, water & wastewater for KMS.

Tenix Alliance Pty Ltd selected eight Model PSH 1500 PURON™ membrane filtration modules from KMS , finding the hollow fibre membrane modules to be the most technically viable and economical solution for the Manildra Group. The system design calls for four trains of two MBR modules each, with space available f or expansion.

Systems with submerged membrane modules are used for some of the toughest wastewater treatment applications, including sewage treatment for municipalities and treatment of

Water Business aims to keep readers alert to business news and new product releases within the water sector. Media releases should be emailed to Brian Rault at brian.rault@halledit.com.au or Tel (03) 8534 5014.

AWA wishes to advise readers that Water Business information is supplied by third parties and as such, A WA is not responsible for the accuracy, or otherwise, of the information submitted.

wastewater for the beverage, textile, food , paper, and chemicals industries.

The single header design and the extremely effective aeration system incorporated in the PU RON module from KMS provide optimal solids management, high flow rate, and reliable operation, while using 50 percent less energy than other submerged MBR systems.

To polish effluent from the MBR, Ten ix Alliance has also selected two MegaMagnum® MM6 reverse osmosis systems. Manufactured by Koch Membrane Syst ems, Inc, each system uses 30 of the world's largest commercially available spiral wound RO elements, the 18" diameter MegaMagnum elements, designed to significantly reduce the cost, footprint, and installation time of RO systems. Each 18" x 61" MegaMagnum spiral element used for the project contains 2,800 ft2 of membrane surface area, compared to 400 ft2 in commonly deployed 8" x 40" products.

Koch Membrane Systems is a Koch Chemical Technology Group, LLC company. For more information on Koch Membrane System visit

IMPROVED METERING PERFORMANCE The latest check-metering technology from Siemens, the Sitrans FUP1010, is a portable clamp-on unit, specifically designed for the water and wastewater industry to measure the performance of existing flow meters with unparalleled accuracy, performance, versatility and compatibility.

With a heavy-duty construction, perfect for any outdoor applications , the FUP1010 check-metering kit adjusts between two modes of operation - transit time operation and Doppler operation to produce optimal measuring results for all technology, aeration and solids percentages.

Transit time operation is the preferred mode for measuring homogenous liquids such as primary sludge, mixed liquor or drinking water applications, with an accuracy of 0.5 per cent of the flow. For liquids containing extensive solids or aeration percentages, such as thickened and digested sludge, the Doppler operation can automatically verify liquids with accuracy of up to 1 per cent of the flow.

This unit is completely portable and comes with all mounting hardware to undertake on-site flow surveys and

WaterGEMS®

COMPREHENSIVE AND EASY TO USE WATER MODELLING SOFTWARE ~ ~~~.!.~~y Bentley WaterGEMS, for water distribution modelling, comes equipped with everything engineers need in a flexible multiplatform environment, from fire flow and water quality simulations, to criticality and energy cost analysis, to flushing and water loss ana lysis. For more information, see the inside front cover of the December issue of Water Journal, visit www.bentley.com/AWA, e-mail sales.haestad @bentley.com, or call +61 (0)3 9699 8699.

water DECEMBER 2008 81

new products & services monitoring of temporary or permanent flow meter installations. The four-hour battery is fully recharged after one hour and the selection of transducers wi ll fit most common pipe sizes and styles.

In meeting the industry's demand for better quality metering data, the checkmetering kit incorporates a 1MB datalogger which produces reports and statistics that can be easily downloaded to a PC via the RS232 cable. Siemens Product Manager, Flow Instrumentation, John Kearton, says the FUP1010 is part of a suite of flow instrument solutions that is designed and constructed to exceed industry standards in metering.

"The functionality and portability of the FUP1010 make it a convenient and accurate measurement and verification tool for the water and wastewater industry, allowing users to be confident of their flow meter's performance. It's specifically designed for the water and wastewater industry, so the it's suitable for checking most installed flow instruments regardless of whether they're based on electromagnetic, ultrasonic, orifice or rotary piston measuring principles."

Mr Kearton says the versatility of the check-metering kit means that "Practically all grades of liquids can be measured w ith high accuracy across many functional areas. From conductive to non-cond uctive liquids, to clean or solids-suspended liquids, the FUP1010 incorporates functions such as flow meter verification, temporary leak detection and verification of highprecision tasks such chem ical dosing."

The Sitrans FUP1010 check-metering kit comes with a flow computer and logger, mounting hardware, transducers, cables and carry case. For further information, please contact Siemens on 131 773 or visit www.siemens.com.au/water. Email: customercare.au@siemens.com

OPTIMISING IN-PROCESS CONTROL The reliability, accurac y and reproducibility of results obtained in wat er and wastewater processes can be

82 DECEMBER 2008 water

dramatically improved by following Good Laboratory Practices and adhering to a good regime of cal ibration and maintenance protocols.

Operators of drin king water and waste plants need to have a high degree of confidence in the results they are recording for a variety of parameters.

These include Nitrogen and Phosphorous contai ning compounds and COD in wastewater plants; chlorine, aluminum, manganese and fluoride in drin king water plants.

These parameters are generally monitored on-site with the aid of a photometer or spectrophotometer and used for important in-process control.

These controls ensure that wastewater plant s are complyi ng with their EPA discharge license agreement and that drinking water plants comply with WHO safe drinking water guidelines on a daily basis.

To obtain accurate and reliable results, an operator performing the daily analysis must have some insight as to what may affect the accuracy of recorded resu lts. If we look at the simplest thi ngs first: a high quality source of de-ionised or distilled water is paramount for the analysis of the above mentioned parameters, particularly with a photometer where a blank (using DI water) is required or any dilutions of sample are performed. Grades of distilled water from supermarkets or petrol stations have no assurances of quality nor do they come with a certificate of analysis. These grades of water may themselves contain high levels of Al, Cl and in many cases high levels of COD. Sub-standard on-site filtering systems are not a guarantee of a high quality, pure water source either. It is recommended that a high quality water source such as Merck GR Water for Analysis, supplied with a certificate of analysis is used.

Accuracy of pipetting and the use of clean tips can also have a dramatic effect on reproducibility and accuracy of results. Frequent calibration and weekly checks to ensure the pipettes used are delivering correct volumes is extremely important. To check a pipette, simply pipette a nominated volume of DI Water (at 20°C) on to a 34 decimal place set of analytical scales (which is also w ithin calibration). A good quality pipette with a clean tip shou ld be within 1 % of the nominated volume.

A robust and easily self-calibrating

pipette like the BRAND Transferpette-S type is reco mmended.

Condition of glassware, particularly the optical glassware and cells, is another factor which can affect the accuracy of results. Photometric determination is an optical measurement, hence, smudge free and scratch free cells (rectangular or round) are essential for measurements with your photometer. Correct cleaning and rinsing of glassware with high grade DI water is essential as surfactants such as detergents can interfere with some parameters, for example Alumini um test kits.

All test kits used on the spectrophotometers themselves come with detailed information on their use, handling and storage. Extremely important sample pre-treatment required for d ifferent parameters, the cleaning and care of glassware and the identification of "influences of foreign substances" are all identified on the packaging inserts supplied with each test kit. Add itionally, with all Merck SpectroquantÂŽ t est kits, the packaging insert also identifies the 'Analytical Quality Assurances' checks recommended to be performed to ensure accuracy of the entire system and to aid in identifying whether foreign substances are having an adverse effect on the operators results. Certificates of analysis of the test kits themselves should also be acquired for the operators own quality assurance records.

Finally the photometer or spectrophotometer itself must be regularly calibrated and serviced by a qualified technician. Baseline zeros must be performed on a regular basis as per instructions in the manual. With Merck's range of NOVA photomet ers and Pharo spectrophotometers, inbuilt Analytical Quality Assu rance functions can be initiated to ensure routine checks are performed with NIST traceable standards.

For further information on how Merck can assist the water industry to improve operator results and optimise their inprocess controls please contact Merck on 1800 335 571 or visit our website at www.merck-chemicals.com.au

WALLINGFORD RELEASES VERSION 9.5 Wall ingford Software has simultaneously released version 9.5 of all six of its core software solutions: lnfoWorks CS (co llection systems), SD (storm drainage), WS (water supply and distribution) RS (river systems), FloodWorks and lnfoNet.

water business

new products & services Paul Banfield, Wallingford Software's Sales and Marketing Director said that the scores of enhancements - many introduced in direct response to customer requests - reflect the ongoing evolution in the role of water modelling and asset management software within the industry: "As the use of water models as a dayto-day operational tool continues to grow, users increasingly need sophisticated software tools and functionality that improve usability, productivity and communication. As well as reflecti ng our ongoing commitment to improve the core function of our products, this latest version incorporates significant additions in application integration, data interrogation and analysis, and aids that will improve the communication of results to nonspecialist audiences."

displaying and distributing model results and network data, particularly dynamic flood inundation maps. V9.5 of lnfoWorks, FloodWorks and lnfoNet sees improvements to the data export options to Google Earthâ&#x201E;˘. These include improvements in export options (layers, objects, names, descriptions, resu lts) and flexibi lity in the way that users can access network data files for use with the Google EarthTM interface (.KMZ, .KML, PNG and .ZIP fi les).

Buck is based in the company's St Kilda Road, Melbourne, office and has more than 30 years experience in various roles in the gas industry and 10 years in electricity. Prior to working for Bilfinger Berger Services (BBS), Buck was Manager Strategic Technical Projects and General Manager Distribution Network Development for SP AusNet. He has also worked for United Energy, Multinet Gas Distribution and TXU Networks.

For complete details of lnfoWorks, FloodWorks or lnfoNet v9.5 please email sales@wallingfordsoftware.com, telephone +44 (0)1491 824777 or visit www.wallingfordsoftware.com.

Russell Ash, General Manager Infrastructure, BBS said: "Peter has extensive experience in gas and electricity and has worked for many of our clients. He will use his strategic, business planning and operational experience to increase the company's portfolio of projects in the gas, electricity, telecom and water sectors, with a focus on the south eastern seaboard of Australia. "

BBS APPOINTS BDM Bilfinger Berger Services (Australia) Pty Ltd has appointed Peter Buck to the position of Business Development Manager, Infrastructure Division. The company's presence in the gas, electricity, telecom and water sectors has grown strongly and Buck has been employed to manage this growth trajectory and identify new business opportunities in these industries.

Buck is a respected industry expert and a significant contributor to the gas and electricity sectors. He is a Fellow of the Institute of Engineers Australia and the Australian Institute of Energy. He has

L Building on the 2D functionality introduced in v9.0 into lnfoWorks CS, SD and RS, v9.5 features an array of enhancements including the introduction of new 2D objects (initial cond ition polygons, outfalls, gullies, point inflows and boundary conditions), multiple improvements to resu lts analysis and export, and the introduction of new ground model modification tools. Very significantly, 2D models in lnfoWorks CS, SD and RS can now be run withi n Fl oodWorks, Wallingford Software's real time flood forecasting and warning system, bringing enhanced modelling of flows through complex river and drainage networks, and for overland flooding simulations.

As users have grown in their need to analyse data in unique and diverse ways , so SQL queries have featured more prominently in Wallingford Software's development programme. Version 9.5 sees the expansion of SQL functional ity across all its software applications to further equip users with the data query capabilities they need.

Due to its affordability, intuitive design and wealth of up-to-date and highresolution geospatial data, Google Earth has become a popular method of

water DECEMBER 2008 83

new products & services been involved with a number of key external industry committees within the Energy Networks Association , currently Chairs the Energy Safe Victoria Audit Committee, and was until recently Deputy Chairperson on the Board of the Electrotechnology and Energy Utilities Industry Skills Council Ltd, a role he held for 11 years. Buck has also received an Australian Gas Association Meritorious Award on two occasions.

"The utilities sector wi ll grapple with many challenges over the coming years including, cli mate change, sustainability, further privatisation and regulatory changes, ageing infrastructure and growing demand for services," said Ash. "BBS will draw on its capabilities in constructing, operating and maintaining utility infrastructure to help industry meet these challenges."

Bilfinger Berger Services is a specialist engineering, construction and asset management contractor in Australia, New Zealand and the region.

Visit: www.bbsaa.com.au.

PORTABLE SOLUTION TO WASTEWATER PROBLEMS A solution t o the problem of wastewater treatment at remote workplaces and population centres has been adopted by Anglo Coal at its new Lake Lindsay open cut mine in central Queensland's Bowen Basin. The wastewater treatment system is applicable to many other unsewered situations including construction sites, wineries, hotels and resorts, schools, shopping centres, caravan parks, sports and leisure centres, and boat marinas.

"The FAST sewage treatment plant is doing the job effectively and economically," said Peter Anderson, Water Plant Technician Supervisor for Thomas & Coffey, who are contract ed to maintain the plant.

Treated effluent waste water from the plant is mixed with mine and runoff water and sprayed on t he mine's coal haul roads for dust suppression. Mr Anderson does weekly, fortnightly and monthly bacterial checks on the effluent. "The resu lts are all great," he said.

Another FAST wastewater treatment system at Anglo Coal's nearby German Creek mine has been runni ng for about 20 years.Supplied by CST Wastewater Solut ions (formerly Contra-Shear Technology) and installed by A1 Noble, the Lake Lindsay installation represents the latest generation of Smith & Loveless FAST systems. These systems offer the following features and benefits: • modular design & construction.

• low sludge production.

• no moving parts, except for an air blower that provides oxygen while ci rculating the liquid.

• req uire little maintenance, with no daily operator requirements and very little annual plant maintenance.

• are robust, in t erms of the process.

Th e fixed media through wh ich the wastewater circu lates provides a hi gh surface area to volume ratio, protecting against hydraulic shock loads.

Built into a standard 20 foot shipping container, the easily transportable FAST (Fixed Activated Sludge Treatment) solution installed at Lake Lindsay is designed to handle 20 cubic metres of sewage per day from the mine site. The Lake Lindsay mine is too far away from the Anglo Coal's other industrial areas to share their facilities, so requires its own equipment maintenance workshops and offices for employees. The 24/7 operation has about 60-80 people working on site at any one time.

84 DECEMBER 2008 water

The Smith & Loveless FAST process has been installed in hundreds of municipal and private developments to industrial and commercial sectors, as well as specialised marine use, according to Michael Bambridge, Managing Director of CST Wastewater Solutions.

Applications include mining and construction sites, petrochemical and chemical plants, pulp and paper producers, food and beverage manufacturers, wineries, meatworks, schools and universities, restaurants, shopping centres, caravan parks, boat marinas, service stations, sports and

leisure centres , hotels and resorts, retirement villages, hospitals, licensed clubs and groundwater cleanup facilities.

FAST is a simple, efficient biological system that offers safety and flexibility for the operator. Unlike conventional suspended growth systems, bacteria grow rapidly on the media while the liquid that evenly circulates through the media is essentially clear, with low solids levels.

As the bact eria grow and increase in thickness, the film strength of the bacterial growth weakens and a sloughing of surface solids occurs. The microbes' anaerobic action results in conti nuing reduction in cell mass and a red uced biological sl udge accumulation to be removed from the bottom of the clarifier. This lessens the req uired area for tankage and associated equipment.

Typically, an extended aeration plant has a mixed liquor suspended solids level (MLSS) of 3000- 4000 milligrams per litre.

At this level the clarifier is being operated at close to the maximum solids fl ux (sl udge accumulation).

With the FAST treatment system the bacteria grow on the submerged media, and the mixed liquor circulating through the bact eria-laden media is essentially clear and free of suspended solids. Th is reduces the MLSS flow to the clarifier to approximately 100-400 mg/L and greatly reduces the amount of solids flux, which means less stress on the clarifier.

For further information, contact Michael Bambridge, 02 9427 1279 email:info@cstechnology.com. au web:www. cs technology. com

INSTRUMENTATION SUPPLIED TO WATER PROJECT Endress+Hauser have been successful in supplying the majority of the process instrumentation to the Western Corridor Re-Cycled Water Project (WCRWP), in South East Queensland (SEQ), including highly specialised engineered solutions to monitor the water quality through the treatment processes.

The WCRWP is one of a number of state government initiatives aimed at securing a future-proofed, c limateindependent water supply for SEQ. The WCRWP will supply purified wat er to industry, agriculture, two power stations as well as supplementing the water flow into Wivenhoe Dam. The initiative has attracted worldwide attention due to the sheer geographic size of the project, its engineering complexity and the innovative technology

implemented, particularly in the water analysis treatment process. In April 2008, WCRWP won the Global Water Project of the Year Award from Global Water Intelligence , at a function in London, beating competing projects from the US and Poland.

Five separate alliances (JVs) were chosen by Brisbane Water to build the pipelines and the Advanced Water Treatment Plants (AWTPs). Endress+Hauser established a number of project teams that worked directly with the control and instrumentation divisions of the respective alliances to assist and advise on the selection of suitable technologies/products for different applications and provide expert opinion on all aspects of engineering, installation and commissioning.

Proline Promag electromagnetic flow measurement

The treat ed water from six sewage treatment plants (STPs) at Oxley, Goodna, Bundamba, Wacol, Luggage Point and Gibson Island will be processed further in three state-of-theart AWTPs at Bundamba, Gibson Island and Luggage Point.

Tech nically, what has excited the industry is the unique combi nation of technologies used in these AWTPs. The wastewater progresses through micro filtration ; reverse osmosis; advanced oxidation; stabilisation and disinfection.

Management of water consumption requires a high degree of accuracy and reliability and not all flowmeters are equal to the task.

The Endress+Hauser Promag is "proven in use" with over l million meters installed worldwide in a variety of applications. Promag sets the benchmark in meeting the unique demands of the water industry:

Endress+Hauser supplied over 1,000 devices at a total value in excess of $6 million. This represented over 80 per cent of the instrumentation commissioned throughout WCRWP's wastewater and advanced wastewater treatment plants. Among the products offered were electromagnetic flowmeters for water flow measurement, thermal dispersion flowmeters for air, ultrasonic level devices, pressure sensors, level switches and temperature sensors - literally a one-stopshop for instrumentation.

• Robust diecast aluminium housing ensures reliability and longevity • Factory fitted and potted cable to guarantee IP68 ingress protection • Separate terminal and electronic compartments safeguard the operations • Increased turndown offers high accuracy even at low flow rates • Simplified installation with no need for earth rings and associated costs • Calibration can be frequently and easily checked with Promag verification tools • Traceability to national and international calibration standards

Endress+Hauser also custom designed air-conditioned cabinets to store the analysis reagents and internal wet racks to house the analysers, as well as pH, conductivity and turbidity systems. This is an extremely critical stage of the treatment process as potable water must have very precisely defined conductivity, pH and turbidity properties.

For example, the Bundamba AWTP uses the latest membrane and advanced oxidation technologies to provide purified recycled water for cooling and other purposes at the power station. The main treatment steps - ultrafiltration membranes, reverse osmosis membranes fol lowed by advanced oxidation using ultraviolet irradiation and hydrogen peroxide - employed at the plant comprise the first largescale indirect potable reuse scheme in Australia.

Given Endress+Hauser's knowledge, experience and virtual Main Instrument Vendor (M IV) status, the company was

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Endress+Hauser Australia Pty Ltd Unit 8, North RydeUnk Business Park 277 Lane Cove Road North Ryde, NSW 21 13 Telephone: +61 2 88 777 000 Fax: +61 2 88 777 099 Tourree: 1300 363 707 Email: lnfo@au.endress.com

Endress+Hauser Ifil People fo r Process Automation

water DECEMBER 2008 85

new products & services subsequently also appoint ed main instrumentation maintenance contractor for all the plants. They wi ll act as a subcontractor to Veolia Water, the company responsible for operations and maintenance of the WCRWP. Upon completion in December 2008, the project wi ll have the capacity to supply 232 megalitres of water per day.

This extremely complex five-alliance project adopted best practices and developed several pioneering solutions and drew on local and international engineering, instrumentation, process control, water treatment and construction expertise. No doubt, Endress+Hauser's unique ability to be a 'one-stop-shop' supplier helped them win MIV status on this chal lenging proj ect.

For more information, tel 1300 363 707, email info@au.endress.com, www.au.endress.com

OIL IN WATER BY UV FLUORESCENCE Enviro-Flu-HC is a new generation of highly sensitive submersible sensors for oil-in-water measurement. The UV fluorescence prin ciple used for detection is much more sensitive than any other existing detection principle such as infrared scattering, etc. This allows the detection of PAH traces in water down t o single ppb levels, e.g. in d rinking water or condensate applications. Typical applications are discharge monitoring of industrial plants, leakage detection and many ot hers.

The Enviro-Flu-HC can even be submerged to 300 metres in depth, in both fresh and salt water. The sensors can be used either in stationary or portable applications. A new innovative coati ng on the lens protects the optics from fouling and oil-films. This makes the EnviroFlu-HC a long term stable option and virtually maintenance free.

86 DECEMBER 2008 water

Typical applications include drinking water, wastewater, airport monitoring, cooling water.desalination, refineries, pipeline leakage detection, marine research and mineral processing.

Environmental & Process Technologies is a division of Bio/ab (Aust) Pty Ltd, tel 1300 735 295, contact: environmental@biolab.com.au

GRUNDFOS STAFF HELP NOVITA Grundfos Pumps Australia understands the importance of being responsible. One of their core value statements is 'Be Responsible', which covers being responsible to the environment and t o the people they live, work and deal with.

To further support these values, on Friday Oct ober 24th 2008, 25 staff from Grundfos Pumps Head Office visited the Novita Children's Services at Regency Park in Adelaide.

Novita Children's Services was established in 1939 as the Crippled Children's Association of SA, to care for children diagnosed with polio. From these humble beginnings, Novita has grown to become one of South Australia's premier children's charities providing quality services to children and families living with physical disabilities, such as cerebral palsy, and acquired brain injuries.

The 25 Grundfos staff vol unteered thei r time to help Novita with housekeeping and gardening jobs in and around t he facility, including planting 250 pot plants and cleaning in excess of 300 chai rs from their well-used bingo hall. The perfect weather had all volunteers in high spirits.

Anna Thyssen, Branding & Communications Coordinator said , "It was a very rewarding afternoon knowing that we are lending a hand t o a charity that does so much great work for child ren with special needs."

Les Goodwin, Finance Manager for Grundfos Pumps Australia said, "Activities like todays are a great way for Grundfos to help local charities and add to the local community. Going forward, we hope to take part in more activities that promot e corporate social responsibility. We want employees, suppliers and customers to know that we are a company who live and demonstrate the Group values."

For more information about Novita Children's Services, please visit www.novita.org.au.

With over 150 employees, Grundfos Australia, together with local sales and service partners, are able to meet almost

all customers' needs within pumping applications across the entire water life cycle.

For further information please contact Grundfos by email at contact au@grundfos.com

OVERCOMING INTERMITTENT PROBLEMS Supplying potable water to densely populated areas in developing countries is a perpetually daunting task for water utilities. It is estimated that 1.6 million people die each year from diseases due to poor service provided by an intermittent water supply.

During non-supply hours, pipes remain empty and dirty water enters the pipeline at vulnerable spots, causing contamination and associated health risks. Transforming these supplies to 24by-7 is a priority for developing economies. Badlapur, India, part of metropolitan Mumbai, is trying to supply its growing population with a 24-by-7 system - a first for the country. The population is expected to reach 300,000 by 201 1.

The transformation of the existing distribution system into a world-class water system requi red a new hydraulic model, according to Dr. Sanjay Dahasahasra, member secretary at Maharashtra Jeevan Pradhikaran (M JP).

The complex model encompassed the city's entire water distribution system and its operating pattern. It also required calibration of the network, analysis of the consumer withdrawal patterns during system modifications, and the creation of new zones and district metering areas to further improve service. Water loss and diversion caused by leaking underground storage tanks and oversized aboveground t anks also complicated the analysis.

The project team used Bentley's WaterGEMS to design the existing and proposed pipelines in Badlapur. Features such as flow-control valves, reservoirs as source nodes, pipe junctions, pipe elements, and demand nodes helped to analyse and optimise the distribution network. The design team used the

water business

new products & services software to create a modelling process to analyse the data, describe the realworld network system, test maps, and synchronise with a GPS. The project required management of a vast amount of data, comparison of permutations, and a combination of a large number of scenarios resulting from various alternative measures to create a comprehensive model. According to Dr. Dahasahasra, using WaterGEMSin this project "Improving the water supply in Badlapur would not have been possible without analysi ng existing conditions using WaterGEMS," said Dr. Dahasahasra. By the early part of this year, eight of the city's 34 wards had been converted to 24-by-7 systems by hydraulically isolating operational zones.

Moreover, the duration of supply in two additional wards has been increased from 3 hours to 18 hours. This progress has greatly improved drinking water quality and reduced co ntamination levels.

The project, which is to be completed by the end of 2009, will serve as a model solution for other cities in developing countries to improve their potable water systems, enhance public health, and meet United Nations Millennium Development Goals.

For more information, visit www.bentley.com

AUSTRALIA'S LARGEST PRECAST CONCRETE STORMWATER RECOVERY Australia's largest precast concrete stormwater recovery, treatment and storage infrastructure has been built on Queensland 's Gold Coast using Humes' RainVaultâ&#x201E;˘ system.

A one megalitre RainVault will be used to recover and reuse stormwater for irrigating parklands and open spaces at Stockland's new 718-allotment Riverstone Crossing residential comm unity at Upper Coomera. In addition to being the largest project of this scale to be constructed with precast concrete components, the new 1ML

RainVault is also the first megalitre system to be inst alled in an Australian residential community.

Stormwater will be diverted from the main drainage through primary and secondary filters, stored in the RainVault and then used to provide a sustainable and cost-effective water supply for the community. Riverstone Crossing 's RainVau lt system is located four metres below ground and has six precast concrete storage barrels, each with a length of 48m.

Each of the six barrels comprises 20 reinforced concrete pipes and 2 reinforced co ncrete end units, all 2100mm diameter and weighing 7 .5 t o 8.8 tonnes. Riverstone Crossing's system has been designed to withstand the loads associated with being more than Sm below the surface due to local stormwater drainage constraints.

Civil Contractors, Nyholt Constructions, inst alled the system by excavating (with benching) about 3,000cu/m t o a maximum invert depth of nine metres, creating a bed for the system that measured 95m long by 35m wide with an average depth of seven metres.

The Riverstone Crossing treatment train and storage syst em was customdesigned by Humes and consulting engineers, Morton's Urban Solutions, to include specific water treatment products for enhancing the quality of harvested water. A Humegard gross pollutant trap, the primary filter, captures litter great er than 5mm such as plastic bottles, cigarette butts and veget ation while two Humeceptorâ&#x201E;˘ units, the secondary filters, ret ain contami nants including free and floating oils, grease, hydrocarbon and petroleum products and fine suspended solids.

There's considerable merit in red ucing reliance on mains supply of potable water according to Col Dutton, Regional Manager - Gold Coast & Northern NSW with Stockland Residential Communities.

"Through our partnership with Humes we've been able to deliver a reduction in this community's long term potable

water demand, combined with the benefit of enhanced parklands and open space areas, a trademark of Stockland Residential Communities," Col Dutton said.

He says water stored in the one megalitre system will be used to irrigate entry statements, parklands and open spaces totalling approximately one hectare at Riverstone Crossing.

For more information , Tel 1300 361 601, info@humes.com.au, www.humeswatersolutions.com. au

NEW CARBON FOOTPRINT ANALYSIS Greeniceâ&#x201E;˘ has launched a new carbon footprinting service based on an innovative and scientifically robust carbon accounting model developed by the Centre for Integrated Sustainability Analysis at the University of Sydney.

This approach uses Input-Output Analysis, a Nobel Prize winning macroeconomic theory.

It is much more practical and cost effective than traditional audit-based footprinting methods. The model uses readily available financial data on expenses and reven ue (sales), and onsite fuel consumption and processes it through a computer model to produce a comprehensive Scope 3 carbon footprint.

The analysis calcu lates Scope 1 emissions (from onsite fuel and energy consumption), Scope 2 emissions (electricity) and Scope 3 emissions that arise in the supply chain. Calculating Scope 3 emissions would normally require an organisation to survey their entire supply chain - and the supply chains of their suppliers; a complex, expensive and virtually impossible task for most organisations. Input-Output Analysis provides a solution to this problem and carries out a complete upstream supply chain life-cycle assessment (LCA) of greenhouse gas impacts at the organisation, plant/facility, project or product level.

The Scope 3 carbon footprint analysis provided by Greenice allows organisations to go much further in efforts to reduce their environmental impact than would be possible by carrying out a traditional Scope 1 and 2 carbon footprint. A full Scope 3 analysis opens up opportunities for organisations to 'green ' their supply chains by working with suppliers to reduce greenhouse emissions embodied in the goods and services purchased by the organisation.

water DECEMBER 2008 87

/

new products & services This is in addition to efforts aimed at reducing direct energy and fuel consumption. Experience shows that a Scope 3 carbon footprint is a powerful way to highlight areas in the organisation and the supply chai n where process improvements can be made. These in turn lead to reduced costs and improved profits.

A Greenice carbon footprint analysis provides a comprehensive greenhouse gas inventory that allows organisations to base-line their carbon emissions and monitor the effectiveness of efficiency improvements, waste red uction and new technology projects.

For more information contact Michael du Plessis, Phone 0402 310 306, Email michael@greenice.com. au

STORMWATER MONITORING PACKAGE John Morris Scientifics' environmental division has announced a complete stormwater monitoring package for research applications, stormwater programs, wetlands monitoring, agricultural run-off studies, and a range of other applications.

Th e ISCO stormwater package provides accurate and reliable data, critical to the process of selecting pollutant traps, creating models to examine current and future run-off needs, or when determining pollutants and how to keep them out of our wat erways.

Using 'off the shelf' components, the major components include a water sampler - to capture both the first flush, and event -weighted run-off; a flowmeter - to trigger the sampler, and determine the pollutant loading; a rain gauge - to record rainfall in the catchment; a suitable power supply such as solar panels and batteries; and ISCO's Flowlink software - to retrieve and analyse the dat a.

For more information on stormwater monitoring and other lsco products please contact Arthur Brien at John

8 8 DECEMBER 2008 water

Morris Scientific on (02) 9496 4200 or email info@johnmorris.com.au, www.johnmorris.com.au

REAL-TIME WATER QUALITY PROFILING John Morris Scientific has released the new YSI 'Automatic Vertical Profiling System' for fully automatic profiling of rivers, estuaries, lakes, dams and storages. It produces more valuable profiling data whilst reducing the number of site visits and by reducing exposure to OH&S hazards in the field .

The Profiling System enables a YSI multiparameter, water quality sonde to measure parameters such as temperature, salinity, DO, pH, turbidity, chlorophyl l and blue green algae throughout an entire vertical column.

Systems are available for fixed site applications such as bridge or water intake towers and for floating applications such as buoy or pontoon mounting in estuaries, lakes, and coastal applications.

Water Advertising

The heart of the syst em is a marine wi nch and corrosion resistant, precision drive assembly that accurately parks the YSI sonde at specific depths and allows for measurement of the desired water quality paramet ers. Data can be stored for manual downloads, or can be retrieved in real time by cellular or radio telemetry systems.

For more information on the Vertical Profiling System and other YSI products please contact Arthur Brien at John Morris Scientific on (02) 9496 4200 or email info@johnmorris.com. au

HORIZONTAL FILTER CONFIGURATION Wat erco has introduced a looped lateral config uration for its entire range of commercial horizontal fibreglass filters.

Conventional horizontal filter lateral systems consist of straight piping fitted with laterals along the length of the horizontal filter.

A conventional lateral system results in uneven fluidisation of the filter media bed. The beginning of the lateral system experiences a strong flow of water wh ich gradually decreases along t he length of the lateral piping. Backwash flow also decreases towards the end of each lateral, resulti ng in non-uniform lifting of the filter media bed.

To reach the decision-makers in the water field, you should consider advertising in Water Journal, the official journal of

Australian Water Association.

For information on advertising rates, please contact Brian Rault at Hallmark Editions, Tel (03) 8534 5000 or email brian.rault@halledit.com.au

Waterco has improved the hydraulic efficiency its horizontal filter lateral system by looping its horizontal filter's distributors and laterals. A looped distribution/lateral system provide a more natural flow of water through the filter than a conventional lateral system.

A balanced water flow over the filter media bed's surface ensures optimum water filtration and a more balanced fluidisation of the filter med ia bed is achieved during backwashing.

new products & services Drives, greatly red ucing programming and set-up time.

Its individual laterals are shortened while maintaining media bed coverage, reducing the friction head loss of each lat eral and further improving the filter's hyd raulic backwash efficiency. The looped lateral system reduces backwash run times, saves water and produces flatter more uniform media bed after backwashing .

Tel: 02 9898 8643 www.waterco.com

ABB LAUNCHES NEW FLOWMETER ABB has launched of a new range of flowmeters specifically target ed at the water, waste water and sewage markets.

WaterMast er has a number of features and functionality to enable users to operate more efficiently, reduce costs and increase profit s. WaterMast er is available in the most commonly installed flowmeter sizes of 40mm to 300mm.

The new unit incorporates an innovative octagonal sensor design. This improves flow profile and reduces upstream and downstream piping req uirements. By using a higher excitation frequency combined with advanced filtering, WaterMaster also improves measurement accuracy by reducing fluid and electrode noise.

'Fit and Flow' data st orage inside WaterMaster eliminates the need to match sensor and transmitter in the field.

On initial installation, the selfconfiguration sequence automatically replicates into the transmitter all calibration factors, meter size and serial numbers as well as customer sitespecific settings. This eliminates the opportunity for errors and leads to increased speed of start-up.

WaterMaster is verified to OIML R49 type 'P' requirement s to ensure the highest accuracy and long term performance of the system by continuous self checking the sensor and transmitter in the field .

For more information see www.au.abb.com

PC SOFTWARE SIMPLIFIES SET-UP The VLT® Motion Control Tool MCT 10 offers advanced programming functionality for all current series Danfoss

Drive programs are managed in a standard folder-based user interface that's famil iar and easy to underst and.

Parameter settings for each drive are contained in a single file, allowing easy duplication of parameter sets between drives. Project folders can also store user-defined files such as PDFs, CAD drawings, or Word documents. It's the one PC t ool for all your drive programming tasks.

VLT® MCT-10 Basic (available free of charge from the Danfoss web site) allows access to a fi nite number of drives with limited functionality. The Advanced edition, offering a higher level of fu nctionality and is available from your local Danfoss Drives sales office or partner.

VLT® MCT 10 features include: • On-line and off-line commissioning • On-board help files for each drive parameter • Logging of alarms and warnings • Graphical tools for simplified programming of t he VLT® Smart Logic Controller and Cascade Controller (FC202 only).

• Scope/graphical function for real-time dat a collection

All WaterMaster sensors are designed to ensure a long, maintenance-free life under the most difficult conditions experienced in the water and waste water industries. The sensors are inherently submersible (IP68, NEMA 6P) as standard , ensuring suitability for installation in chambers and metering pits which are liable to flooding.

A feature of the WaterMaster sensor is that all sizes can be buried. Installation involves excavating to the underground pipe, fitting the sensor, cabling to the transmitter and then backfilling the hole.

In the field, WaterMaster's backlit, graphical display can be easily rot ated through 270 degrees without the need for any tools, allowing field teams to customise the display that best fits their needs. 'Through-the-glass' control allows local operator interface to input short, quick data for all user specific parameters.

VLT® Motion Control Tool MCT10 simplifies commissioning & faultfinding on the entire current series of VLT® Drives.

water DECEMBER 2008 89

new products & services • Configuration and access to the VLT® Drive's internal data buffer, providing up to four channels of high speed (down to 1 milli sec) data collection Connection to all current series VLT® FC 102/202/301/302 Drives is direct via USB cable to PC, without the need for a converter or power supply. A USB extension cable kit is available as an option for all IP55 & 66 VLT® Drives, to allow connection without the need to remove the front cover of the drive, thus maintaining the ingress protection rating.

For further information on how VL T® MCT10 Set-up Software can benefit your business, please contact Debbie Busuttil on 03 9703 5103, your nearest Danfoss Drives office or visit www.danfoss.com/pacific To download the basic version http://www. danfoss. com/Pacific

M ANAGING THE EXTENT OF BOM Most water authorities spend large amounts of money on water treatment infrastructure, operator training, dosing chemicals, etc to ensure excellent quality drinking water at the plant. Unfortunately most customers receive water that has been through a distribution system and this process can be jeopardised by poorly maintained and/or old pipes.

The major culprits for causing a 'dirty' distribution are biofilm build-up and mineral deposits such as iron and manganese. This build-up within the d istribution can lead to customer co mplaints such as colour, taste and odour. More importantly this bui ld-up contributes to chlorine demand and pot ential microbiological regrowth which can lead to breaches of the Australian Drinking Water Guidelines.

The most common way to combat this problem is to pig or clean the distribution system reg ularly. This is an effective met hod however it causes inconvenience to the customer, large amounts of water wastage, and significant costs in labour and equipment for the water utility. A more effective method is to manage the amount of biodegradable organic matter (BOM) within the treated water supply.

The most common indicators for measuring BOM are biodegradable dissolved organic carbon (BDOC), assimible organic carbon (AOC) and biological regrowth potential (BRP).

90 DECEMBER 2008 water

the DOC that has been utilised by the bacteria present on the substrate and is therefore the biodegradable component.

BDOC is the fract ion of dissolved organic carbon that can contribute to biofilm growth within the distribution system. Most oxidising processes withi n the water treatment plant contribute to the formation of BDOC including ozonation and chlorination. BDOC is usually made up of the small molecular weight molecules which contribute to chlorine demand and trihalomethane (THM) formation.

The best method of controlling BDOC in your distribution system is to treat the water with a biological process prior to disinfection and distribution. By using a biological filtration media such as biological activated carbon (BAC) the bulk of the BDOC of the water will be removed. Most drinking water plants in Australia that use ozone in conjunction with BAC find their chlorine demand and THM formation within the distribution decreases by around 50% and distribution maintenance is reduced with less cleaning required due to less biofilm growth .

BDOC is measured by placing a water sample in contact with a biological substrate under aeration for a number of days. The DOC concentration at the end of the test is subtracted from the initial DOC concentration and the difference is considered t he BDOC. This component is

Research Laboratory Services uses the Joret Method for BDOC determination.

Due to the sensitivity of this test all tests are conducted in duplicate at no additional cost. Peta Thiel is one of the three people in Australia that has been personally trained in Paris by Joret's laboratory staff.

Please call Peta for more information on (03) 9431 2595 or email peta@researchlab.com.au

MEMBRANE TECHNO LOGY PROVIDES SCALABLE SOLUTIONS Water Infrastructure Group is using advanced membrane technology to provide high quality water t reatment solutions. Peter Everist, Water Infrastructure Group General Manager, said that membrane technology is a sustainable and scalable solution for producing water that can be tailored to suit the raw water quality and the prod uct water end use.

Water Infrastructure Group is using advanced membrane technology to provide high quality water treatment solutions.

r business

new products & services "Membrane technology can be used to create a relatively secure supply of fit for purpose water that augments and frees up other water resources for potable water supply, irrigation and environmental flows. The modular nature and small footprint of this technology means that as well as being suited to t he traditional approach of building large plants and pipeline networks, we can also look at options of building smaller plants to produce water at the end use location," Peter said.

In Sout h Australia, Water Infrastructure Group delivered 16 ultrafiltration units for nine towns along the Murray River. The 900 kUd units are designed to filter turbid water from the Murray River to augment potable water supplies for the towns. In Western Australia, Water Infrastructu re Group delivered t hree 500 kUd containerised, continuous ultrafiltration water treatment plants for remote townships t o filter bore water t hat was high in organics.

Water Inf rastructure Group is a Tyco International Ltd company and provides design, build, operate and maintenance services for water/wastewater treatment, recycling and distribution infrastructure.

Some current projects from its portfolio include: • Adelaide Desalination Pilot Plant • Barwon Water Biosolids Management Project in Geelong

FLOATING EFFLUENT PUMP ON THE FARM Melbourne based B.R. Reeve Engineering began to develop a Dairy farm effluent pump over 50 years ago when the company's founder, Bernie Reeve, worked with Gippsland farmers who wanted to move the manure dropped by dairy cows during milking from near the dairy out to pasture.

It took decades for the dairy industry to realise this 'waste effluent' was in fact 'free fertiliser'. Over the years the Reeve Effluent pumps evolved from a simple horizontal centrifugal pump into the current Vertical Cantilever style pump which offers significant operational advantages such as no bearings or seals underwater resulting in almost maintenance free long life performance.

A major development in effluent handling was the introduction of multipond syst ems which allowed for washdown water to be recycled and for the effluent to be stored during the high rainfall season (winter) for later distribution over pasture.

But with a pond system farmers were faced with the difficulty of where to locat e their pump unit since the water level rose and fell during the seasons and earthen banks were unstable, the solution - a floating pontoon with the 'always primed' pump safely drifting around on the tide.

Reeve Engineering has supplied dozens of their 2" wastewater and effluent pumps mounted on their floating pontoon system to dairy, piggery and abattoir operations, but when Consulting Engineers GHD approached t hem with a requirement for floating 2 x 6" high capacity submerged pumps and associated equipment with a total mass close to 1000 kg it was back to the drawing board.

The pump system was required by a Regional Water Authority to pump 'dead water' from a local reservoir where years of drought conditions had caused the water height to fall below the normal take-off level. The problem was solved simply by joining two pontoons back-toback and mounting the worki ng deck and pumps along with four positioning winches and electrical board on a specially designed and in-house fabricated hot dipped galvanised frame.

An additional two pontoons were added at right angles to those shown in the photograph formi ng a large 'cross' allowing a maintenance crew to board the pontoon from a dingy and work on the platform in a stable and safe environment. The success has led to further opportunities in the mineral processing industry, large scale sewage lagoons and waste water operations.

Contact: B.R. Reeve Engineering on (03) 9699 7355, email: engineering@reevegroup.com. au, www.reevegroup.com.au

• Campaspe Water Reclamat ion Scheme in Echuca • Eastern Irrigation Scheme in Melbourne • Mangawhai EcoCare Project in New Zealand • Moura Wastewater Treatment Plant in Queensland • Surbiton Park Recycled Water Plant in Melbourne • Virgi nia Pipeline Scheme in Adelaide More information on Tyco can be found at www.tyco.com.

Pontoons for Pumps * Vertical Cantilever Effluent Pumps available * Bare Pontoons with Gal frames in stock

* Multi-pontoon pump rigs to customer design T: 03 9699 7355

F: 03 9696 2956

www.reevegroup.com .au

wat er DECEMBER 2008

91

advertisers' index I

COPON°,. ANO THOATEX1 ~

MEMBER OF

HAVE BEEN REBRANOEO TO FORM PART OF THE SCOTCHKOTE'" PRODUCT RANGE FROM 3M

M=lli=ilHIH14Wi

www.pipelinings.com

3IVI

ADVERTISERS' INDEX Acacia Filtration Systems

71

ITT

13

Allflow Supply Co

22

James Cumming & Sons

65

Allflow Supply Co

77

John Morris Scientific

23

KSB Australia

15

Aquatec Fluid Systems

9

AWMA Water Control Solu1ions

11

MWH

Water Advertising To reach the decision-

3

makers in the water MWH

AWMA Water Control Solutions

66

80

field, Noblewater

Bentley Systems, Inc inside front cover

Bentley Systems, Inc

81

Black & Veatch

45

By-Jas Engineering

you

should

8

consider advertising in

Norit X-Flow

43

Orica Watercare

31

Water Journal, the

Plasson

41

official journal of

Redox

63

Australian

Reeve Engineering

91

Research Laboratory Services

42

Trojan Technologies

35

For information on

Tyco Flow Control

17

advertising rates, please

Tyco Water

25

contact Brian Rault at

Vinidex Systems & Solutions

21

18

Copon Pipelinings

92

Ecowise Environmental

14

Endress & Hauser

85

Environdata

83

Gale Pacific

37

Grundfos

7

Grundfos

19

Hanna Instruments

64

Hatch

70

Humes Water Solutions

57

Water

Association.

Hallmark Editions, Tel Vinidex Systems & Solutions inside back cover

Wallingford Software

(03) 8534 5000 or email brian.rault@halledit.com

outside back cover

International Protective Coatings

92 DECEMBER 2008

.au 33

water

Water Infrastructure Group

32

water business

Wallingford Software smarter solutions for the water .industry I

lnfoWorks RS surface flood modelling

With the increasing frequency of extreme flood events, managing the flow of water in rivers and coastal floodplain areas has never been more important. lnfoWorks RS is an advanced modelling tool that combines 1D simulation of flows in rivers and channels with 2D simulation of surface flood modelling in the floodplain and urban environment.

Infi Works.. RS lnfoWorks RS geographical and sectional views

• Full solution modelling of open channels, floodplains, embankments and hydraulic structures • Fully integrated breach modelling for homogeneous and composite embankments and dams through overtopping, piping or surface protection failure • Rainfall-runoff simulation using both event based and conceptual hydrological methods • Interactive geographical plan views, 3D views, sectional views, long profiles, spreadsheet and time varying graphical data • Animated presentation of results and analysis using maps, tables

lnfoWorks 2D animated maps of depths & velocities •

and graphs Full flood-mapping capability based on a sophisticated floodinterpolation model overlaid onto an imported ground model

InfoWorks.. 2D lnfoWorks RS dynamic breach modelling

• Ideal for modelling flows over large rural areas and complex urban environments • Accurate and effective modelling of flows through streets, around buildings and over open ground • 2D elements fully integrated within the 1D network • Includes tools for the creation of 2D meshes and fully animated maps of flood depths and velocities

"By using 1D simulation to identify where flooding happens, and then using the CP!Jlbined .1D ar.id 2Ds imulation to investigate the ..,. - directfon a nd depth of flood flows in these smaller areas, users can achieve a cost-effective balance between model-building time and simulation accuracy."