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AWA AUSTRALIAN WATER ASSOCIATION ABN 78 096 035 773

FEATURES COASTAL CRC MEMBRANE TECHNOLOGY


Volume 32 No 1 February 200S Journal of the Australian Water Association

Editorial Board F R Bishop, Chairman B N Anderson, G Finke, G Finlayson, G A Holder, B Labza, M Mumisov, P Nadebaum, J D Parker, F Roddick, G Ryan, S Gray, A Gibson, P Mosse Water is a refereed journal. This symbol indicates char a paper has been refereed.

Submissions Instructions for authors can be found on page 2 of chis journal. Submissions accepted at: www.awa.asn .au/publicarions/

Managing Editor Peter Stirling

Technical Editor EA (Bob) Swinton 23 Blaxland Road Wentworth Falls, NS\Xf 2782 Email: bswinton@bigpond.net.au

OPINION 2 Tsunami Responses; The World's Water Meeting; My Point of View, D Dreverman ASSOCIATION ACTIVITIES 6 AWA's Response to the Tsunami; National Water Week 200S INTERNATIONAL 8 WaterAid Australia Update; IWA Australia PROFESSIONAL DEVELOPMENT 10 Details of courses, classes and other upcoming water events CROSSCURRENT 12 Industry news FEATURES 20 Funds from the National Golf Day Assist with Project in Papua New Guinea

FEATURE: COASTAL CRC

News Editor Clare Porter Communications Manager Tel +6 I 2 94 I3 1288 Fax: (02) 94 I 3 I047 Email: cporrer@awa.asn.au

21

OVERVIEW D Alcock

22

L J SEPTIC ABSORPTION TRENCHES: ARE THEY SUSTAINABLE?

Why are septic systems 'on the nose' in Australia?

Water Production

C Beal, E Ga rdner, N Menzies

Hallmark Editions PO Box 84, Hampton, Vic 3 I88 Level 1, 99 Bay Street, Brighton, Vic 3 186 Tel (03) 9530 8900 Fax (03) 9530 89 I I Email: hallmark@halledit.com.au Graphic design: Mitzi Mann

27

[ •~ IMPACTS OF SEWAGE OVERFLOWS ON AN URBAN CREEK

Measuring the ecological and public health impacts. P Pollard , R Leemi ng, S Bagraith , M G reenway, N Ashbolt

33

COASTAL WATERWAYS PUBLIC AWARENESS CAMPAIGN

Regional television is by far the most visible source of information.

Water Advertising

D Alcock

National Sales Manager: Brian Rault Tel (03) 9530 8900 Fax (03) 9530 891 I Mobile 0411 354 050 Email: brault@halledit.com.au

Water (ISSN 0310 - 0367) is published eight times a year in the months of February, March, May, June, August, September, November and December.

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36

J Mackenzie, 38

Rod Lehmann

Chief Executive Officer

~

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FEATURE: MEMBRANE TECHNOLOGY 40

year. Jt is also available via subscription.

NEW DEVELOPMENTS IN MEMBRANE TREATMENT PROCESSES: PART 2 - WASTEWATER REUSE Advanced wastewater reuse using membrane treatment. R Tarr

49

THE 1.7 ML/D DALBY GROUNDWATER DESALINATION PROJECT A small inland town goes for desalination. T Fagg

ASSET MANAGEMENT 55

JUNCTION SEALING - A UNIQUE PROBLEM No-dig house service lining systems for Australian conditions. R Petterson, A Sutton

58

MANAGEMENT OF RISK IN PIPELINE ASSETS A suite of models for management of water supply network assets. S Burn

WATER BUSINESS 60

Water is senr to all A\Y/A members eight rimes a

COASTAL MANAGEMENT TRENDS IN THE ASIA-PACIFIC REGION T Smi th, D Tho msen

AUSTRA LIAN WATER

Chris Davis ASSOCIATION Aust ralian Water Associarion (A\XIA) assumes no responsibility for opinions or statements offacrs expressed by contributors or adverrisers. Edirorials do not necessarily represent official A\Y/A policy. Advertisements are included as an information service to readers and arc reviewed before publication to ensure relevance to the water environment and objectives of A\Y/A. All material in Water is copyright and should not be reproduced wholly or in part wirhour written permission.

P O liver

A report on the 2004 Coastal Zone Asia Pacific conference.

AWA

President

EFFECTIVE REGIONALISATION IN COASTAL NATURAL RESOURCE MANAGEMENT

Relationships between a regional body and community-based groups.

NEW PRODUCTS AND BUSINESS INFORMATION SPECIAL FEATURES: PIPES AND MEMBRANES

Visit the

Australian Water Association

HOME PAGE

and access news, calendors, bookshop and over l 00 pages of information ot

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OUR COVER: Urban and peri-urban development along the eastern seaboard ofAustralia is having enormous impact on both the land and water environment. The Coastal CRC was set up to provide knowledge and tools to assist proper management ofthe coast and its associated estuaries and waterways.


TSUNAMI RESPONSES The tsunami crisis on Boxing Day certainly jolted us all with its sta rk reali ty and associated devastation. The response from Australians has been remarkable, as indeed has been the response from AWA members. We have had a huge amount of phone calls and emails asking how people can help. Clare Porter has coordinated our activities and has sec up a database of membership offers of assistance. She has three categories: members who have offered to help, members who have offered to be mentors and member companies/ organisations who have offered to provide goods and services. Th is information is being sha red with the appropriate disaster relief agencies. I attended a meeting organised by the lnsti w cion of Engineers Australia on 12 January organised to coordinate an engineering response to the emergency operations. le was chaired by AWA Past President, Professor Mike Dureau, who is now Internacional and Australian Chairm an of Registered Engineers for Disaster Relief (RedR). Ocher attendees incl uded represen tatives from the United Nations High Commissioner for Refugees (UN HC R), AusAID, RedR, the Austral ian Defence Force and CEOs, universities

support or would like further information should contact Clare Porter on cporrer@awa.asn.au. New Governance a nd Younger Members

that role. The Prime Minister is co-chairman of the AustraliaIndonesia Partnership for Reconstruction and Development (A IPRD), so he plays a key role in che region. • Assist with the assessment, planning and implementation advice to lead agencies such as AusAJD, Emergency Management Australia (EMA), the ADF, Geoscience Australia and also to state governments, with primary emphasis on Indonesia. • Jn the short term , assist the UNHCR and RedR in sourcing temporary facilities and expertise through in-cou ntry representatives, Austra lian contacts and existing and newly established registers and databases.

The response from Australians has been remarkable, as indeed has been the response from AWA members. and representation from major Australian companies and ocher organisations and associations. The outcomes of the meeting were chat che group which met will: • Form the basis of an advisory panel to provide high level engineering and construction advice to the Prime Minister. Because of its unique access to extensive resources of engineering expertise and sk ills, chis group is ideally suited to

2 FEBRUARY 2005

water

• Establish a small peak group, meeting as required, to receive and collate requests for assistance from government and lead agencies and to co-ordi nate responses co chose requests on a continuing basis. • Establish a network based on the associations and ocher groups attending the meeting, or identified subsequently, to support the peak group. In the meantime AWA members who are keen to offer

Over the Christmas/New Year break nom inations were received fo r our new board. Nominations are now closed and the new board will be selected at the meeting of the new Strategic Advisory Committee (SAC) on 26 February; it will then cake over at Ozwacer 2005. This will be an histo ric event. There will also be a meeting of che old Board and the Strategic Advisory Committee to sec strategic directions for AWA for the next 12 months. One issue we will be discussing at the SAC meeting is how to engage greater involvement of our younger members. We need to establish internal structures which encourage the engagement of younger members, freeing them of some of the bureaucratic, dare I say it, formalities chat senior members of the Association, like me, are more familiar with. We will be addressi ng chis at the next board meeting, but I welcome any thoughts you may have on chis. A National Operators' Association

At the time of writing chis report I am sitting on a plane heading co Melbourne to attend

water FUTURE MAJOR FEATURES MARCH - Susta i nab i l ity, Wa stewater Treatment, Odour Control

MAY - CRC Freshwater Ecology , Membrane Tec hnology

JUNE - Ozwater Conference Report

a meeting to discuss the esrablishment of a National Water Operators Association. Ac the invitation of the Water Industry Operators Association (WIOA), AWA is looking to assist in che creation of a truly national operators' group chat will provide services com plementary to chose from AWA. The rwo organisations, between them, will ensure char the interests and needs of everyone in the water industry are well served. The rwo associations will also collaborate with the Water Services Association of Australia (the major utilities' trade organisation) to ensure that issues like training and retaining necessary skilled people are properly add ressed. Rod Lehmann

water

Contributions Wanted

\Irater journal welcomes the

submission of papers equivalent to 3,000-4,000 words (allowing for graphics) relating to all areas of rhe water cycle and warer business to be published in the journal. Topical stories of up to 2,000 words may also be accepted. All submissions of papers intended for the main body of the journal should be emailed to the Technical Editor, bswinton@bigpond.net.au. Shorter news items should be emailed to news@awa.asn.au. A submitted paper will be tabled at a monthly Journal Comm ittee meeting where, if appropriare, it will be assigned to referees. Their comments will be passed back to rhe principal author. If accepted and after any comments have been dealt with, the fi nal paper can be emailed with rhe text in MS Word bur with high resolution graphics (300 dpi tiff, jpg or eps files - Zip disks or CD-ROMs can be accepred) as separate files, or hard copy photos and graphics suitable for scanning by the publisher can be mailed to 23 Blaxland Rd, Wentworth Falls, NSW 2782.


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Australia's vase coasral zone is sufferi ng many direct and indirect pressures. Dereriorarion in water quality, urban sprawl, fragm ented planning, loss of nacural habitat, depleted fisheries, com peti tion for resou rces, increased erosion, ovcrdevelopmenc, and pollution of waterways muse all be better managed if we wa nt co maintain our quality of li fe. The Cooperative Research Centre for Coastal Zone, Estuary and Waterway Management (Coastal CRC) was estab lished in 1999 co deliver cools and knowledge co help plan, manage and improve rhe health of our coast, estuaries and waterways. T he Coastal CRC, now in irs sixth yea r of funding, creates partnershi ps co find

solutions fo r these social and environm ental problems by develop ing: • decision-making cools co plan, manage and evalua te coastal resource uses in urban , industrial and agriculcural catchm ents; • management and restoratio n srraregies for ecosystem health and improved quality of life; • rechnologies co assess, monitor, map, understand and manage coastal ecosystems; • ski lls for co nsulting co mpanies, government agencies, community groups and industry; • education and training opporruniries for narural reso urce managers. We are continually challenged co make difficult decisio ns with limi ted information

The Coastal CRC Partners • Brisbane City Council • Central Queensland University • CS IRO • Curtin Uni versity of Technology • Defence Science and T echnology Organisation • Geoscience Australia • G rifftch Universiry • James Cook University • Queensland Department of Primary Industries and Fisheries

• Queensland Environmental Protection Agency • Queensland Department of Nacural Resources and Mines • University of Queensland • University of Western Australia. T here are also many private companies and community organisations involved as associate partners.

- about the bio-physical sysrems, rhe diversity of reso urces, co ntinued urban development, and regional plans char accommodate our social, environmenral and economic values. T he Coastal C RC is add ressing rhese deficiencies in our knowledge of the coasral zone and is developing new coo ls, such as OzEstuaries and a Citizen Science Toolbox, for industry and government. T he articles in chis fearure for rhe Journal Water include rwo which are directly related ro warer qu ali ty in estuaries. There is a study of environmental and public healrh impacts from sewage overflows along a tidal creek in Brisbane and an assess ment of septic absorption syste ms to rreac domesric wasrewacer in Australia. There are three articles wh ich relare co social science including a review of regional partnerships in narural resource management and a case study of a successful regional media campaign - since probab ly the most significant impact on our coastal catchments and escuaries is chat of urban and peri-urban development. Contact

Coastal CRC, 80 Meiers Rd , lndooroopilly, Queensland, Australia, 4068. Phone: 61733629399, Fax: 6 1 7 3362 9372, Web: www.coasral.crc.org.au

water

FEBRUARY 2005 21


SEPTIC ABSORPTION TRENCHES: ARE THEY SUSTAINABLE? C Beal, E Gardner, N Menzies Introduction The most common on-sire wastewater treatment system (OWTS) in Australia is the septic tank - soil absorption system (SAS) . In chis paper, an introduction of some management issues and public perceptions of SAS is fo llowed by a description of rhe key mechanisms and hydrology of SAS. Th is paper also discusses the performance of SAS, particularly in terms of the current and future role of SAS in sustainable management of domestic wastewater in Australia.

16% 10,000

How Many Systems are there in Australia/United States T he distribu tion of OWTS in Australia in 200 1 is presented in Figure 1 based on figures reported by O'Keefe (2001). Over 1 mill ion systems were in operation over Australia in 2001 wirh rhe greatest number in NSW (300,000), Vicroria (250,000) and Q ueensland (250,000) . The most co mmon (>80%) OWTS in Australia is rhe septic tank - soil absorption system (SAS) . Assuming a daily consumption of 200L per person, at an average of 2.6 person/house, 700ML of effluent may be generated daily. That is around 31,500 kg of nitrogen, 8,400 kg of phosphorus and 70 x 10 IO faecal col iform organisms: on-sire wasrewarer treatment is a serious water management issue. In the United Scates 25% of households (;::;; 60 million people) use OWT S (predominantly SAS) , with an estimated one-thi rd of new developments to be nonsewered (USEPA, 2002). The percentage of non-sewered sites in rhe US has not decreased fo r the last 3 decades, rather they are co nsidered a permanent and viable alternative co reticulated sewerage.

Why are Septic Systems 'On the Nose' in Australia, Yet Accepted in America? T he USEPA response to Congress on the long-term viability of OWTS draws on the accumulated knowledge gathered from decades of investigation across many states: "Adequately managed decentral ized wastewater treatment systems are a costeffective and long-term option fo r meeting public health and water quali ty goals,

22

FEBRUARY 2005

water

38%

58,000 ---

Figure 1. Di stribution of on-s ite wastew ater systems i n Austral ia based on figures presented in O'Keefe (200 l ). Percentages indica te the proportio n of non-sew ered properties in each state. *Updated Queensland statistics from recent studies by N. Diatloff (pers. comm.) and Beal et al. (2003a).

particularly in less densely populated areas." (USEPA, 1997). Despite this, SAS continue to have a mixed reputation both with the Australian public and local authorities. Unpredictable and variable perfo rmance, together with limited scientific investigation, have perpetuated the bel ief that the SAS is a sub-standard and outdated means of on-sire wastewater treatment. T his is somewhat puzzling given

predecessor, AS 1547: l 994, signified a positive shift toward improved on-sire system management. Prior to AS1547:1994, trench design was loosely based on technical concepts and largely based on local knowledge and 'rule of thumb'. AS15747: 1994 was a prescri ptive guide to des ign ing not only SAS but also surface irrigation areas for aerated wastewater treatment systems and sand filters. In 2000,

The evidence that septic tank - soil absorption systems cause widespread and serious pollution is by no means conclusive. chat the evidence to support the argument that SAS cause widespread and serious pollution is by no means conclusive.

On-site System Regulation in Australia Regulatory guidelines for OWTS Management is fragmen ted in Australia, with many states opting to adopt their own OWTS management framework. The relevant Aus tralian Standard is AS/NZS 1547:2000. The publication of its

a revised Standard, incorporating Standards New Zealand was published. AS/NZS 1547:2000 is a more performance-based approach to the design and management of on-s ite systems. T his has been received with mixed response by the industry.

A Recent Audit of Septic Systems in

SEQ Recently, a review of OWT S management practices in so uth-east Queensland was carried out by rhe Qld

refereed paper


coastal ere Departm ent of Natu ral Resources and Mines fo r rhe Moreto n Bay Waterways and Catchments Partnership. Key management issues were notably rhe freq uency of greywater failure and inappropriate greywater discharge. Mosr early SAS were split greywa rer/blackwarer sys rems where blackwater, usually less than 20% of rhe to tal in ternal household warer use, is disp ersed in to separate trenches. The majori ty of SAS (>70%) were installed pre1994 which preceded rhe release of Australian Standa rd AS 1547: 1994, so these ea rl y systems were nor being designed as a fun ction of soil type and effluent vo lum e bu r rather usi ng a 'rule of thumb'. Failures were reported in poorly designed older trenches, and rhe newer co mbined septi c systems. Nonetheless, reported SAS failures were low (Figure 2), fo r example Gold Coast reported up to 200/yea r - on ly 2.2% of all their SAS. Despite the low reported fai lures, there was wides pread opinion by local amhorities that this was a substan tial under-reporting of the real situation.

How Do Soil Absorption Systems Work? It's More Complex than you Think! Wastewater undergoes primary trea tment in rh e septi c rank via sedimentation and anaerobic digestion. Secondary treatmenr of the septic rank effluent occurs within th e trenches and surrounding soil (F igure 3) . T he mechanisms governing purification and hyd raulic performance of SAS have been

21 %

10 % ~ 5 9% 10%

D Surcharge

• Odow·

D Off Site Risk

D Tank Disrepair

(a)

Figure 2. (a) Classification of major septic system failure as identified by SEQ Local A uthorities (% = % of responses from Local Authorities); (b) N umber of reported failures per year for septic systems (Beal et a/, 20030), note: pie slice = % of tota l septic systems in SEQ. shown to be highly inf1uenced by a biological zo ne ar rhe interface of rhe bottom of the trench and the soil, termed rhe biornat (Figure 3c). T he biomar zone is made up of amoebas, rorifers, protozoans, fi lamentous bacteri a and in organi c particulates. T he biomat zone is ' fed' by rhe suspended solids (SS) and organic matter (BOD) in rh e septic rank eff1uen r and beco mes increasingly imperm eable to f1ow as ir develops. T he f1u x through the biomar zo ne is less rhan rhe saturated hydraulic conducriviry of rhe underlying soil and therefore creates unsaturated f1 ow co nditions in the so il (Figure 4) . T he secondary rrearment process in a SAS, much like sand filters and biological trickli ng filters, relies on prolonged co ntact with media in an ae robi c en vironm ent to rrear eff1uenr poll utants (nurriencs, SS, BOD and pathogens). Tn the case of a SAS, rhis

Production Dispersa l Emwrranspimrion

IS11b1urfau Disz,oJ<AI Sprt.:m

Soil

Lay9'(_ L Pur(fic:afion I £ i

~-'\ _ __

I //

/

Wacn-Table

\ \

-........

(a)

Septic tank

clllucnt

gravel trench

(c) Cross section of distribution pipe in grave l trench

Figure 3. Schematic of layout and main processes (a); plan and cross section view of the trenches in a septi c absor ption system (b

refereed paper

aerobic environment is provided by the unsa turated soil zo ne created by the hydraulically resistant biomar zone. The relatively long hyd raulic retention time in the unsaturated so il provides opportuni ty fo r treatment processes such as oxidation , adsorption, die-off, and ion exchange.

What is the Role of Soil in the Septic System Process - Do Differences in Soil Type Really Matter? Although unsarurared f1ow characteristics vary between so ils, studies have indicated char the biomar zo ne acrs to regulate the long term acceptance rare (LTAR) to a narrow range, regardless of so il rype (Bouma, 1975) . This was also fo und by Beal et al. (20036) where a four order of magnitude variation in saturated hydraulic conducti vities between soils collapsed to a one to rwo order of magnitude LTA R under the inf1uence of low permeable biomar zone (Figure 5) . Soil hydraulic co nducriviry characteri stics are important for hyd rauli cs in SAS bur are rhey as important fo r effluent treatm ent? Several investigato rs report rhar soil chemical properties are a key in eff1uenr rrearm ent (Dawes and Goonerilleke, 2003; McCardell and Davison, 200 3) suggesting that finer-grained (clay) so ils are particularly effective in treatm ent. However, rhe efficiency of sand med ia in the reduction of BO D, SS and pathogens is also well documented (Cri tes and T chobanoglous, 1998), despite the relatively low physicochemical activity of sand. A SAS acts much like a sand filter when unsaturated co nditions are present below rhe biomar zone and rh ere is suffi cient depth to groundwater. Soil rype may nor be as importan t as rhe depth of unsaturated so il fo r effec tive eff1uenr treatment.

5cm)

zone (b) P!an view of distribution pipe in

• o-5 per year (Boonah, Toowoomba, Crow's Nest, Kllcoy)

El 5-1 0 per year (Esk, Gatton) C 10-25 per year (Brisbane, Laldely, Pine Rivers, Redland) C 25-50 per year (Caloundra, Ipswich, Logan) • 50-75 per year (Maroochy) D 75-100 per year (Beaudesert) El 100-150 per year (Caboolture, Noosa) Cl 150-200 per year (Gold Coast) (b)

& c).

What are Main Types of Septic System Failure? H ydraulic fai lure occurs if the eff1 uenr loading rare in to rhe trench is greater than th e infil tration rare rhrough the biomar

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FEBRUARY 2005 23


zone. This will resulc in ponding of wacer wichin che trench and surface surcharging of effluent above the crench (Figure 6) . Hydraulic failure can be separaced into 'catastrophic' and ' periodic' failure. Catastrophic failure occurs from solids ca rry-over in che septic tank combined wich the narural biomat zo ne, chus clogging infiltracive surfaces and inhibicing f1ow into the subsoil. T his is usually an irrevocable failure. Episodic failure is a te mporary condition where peak loadings into che crench occur from increased water use or prolonged rain fall. In chis siruacion, che water may pond to che surface, however infiltration, particularly through che trench sidewall, will still co ntinue, resul ting in evenrual draining of wacer. Sidewall exfil tration above che biomac zone has shown co be a key pathway for excess water in permeable soils (Beal et al. , 2004) . Treatmenc failure rela tes to insufficienc hydraulic retention time wichin che so il matrix thus precluding adequate treatment of effluenc befo re entering the groundwacer. This can occur through a poorly designed SAS, a shallow wacer cable or sarurated f1ow from the crench (poor development of biomat zone) .

Figure 4. Cross section of trench with increasingly resistance biomat zone (top) resu lti ng in increasingly unsaturated flow (below).

Australian investigations have demonstrated co ncl usive evidence of OWTS-sourced pollution, and these have utilised tracers to track the contami nant plume originating from the effluent dispersal zone (Gerritse et al., 1995; W hitehead and Geary, 2000; Geary, 2004). T here is also evidence demonstrating a low impact from SAS. Whitehead and Treatment Efficiencies - How Much Geary (2000) reported elevated nitrate Soil do you Need? concentrations but fo und faecal coliforms Effluent passage through the biomat zone to be almost undetectable in groundwater and the upper unsarurated soi l of a SAS from a non-sewered communi ty in significantly reduces BOD and SS. Soil Tasmania. Cromer (2 001 ) found greatly column experiments and field monitoring reduced concentration of nitrate and faeca l suggests chat, wich the excepcion of nicrace, colifor ms in a sandy aquifer 1Om from a adequate treacment of effluent can occur SAS. Gerritse (1995) repo rted high wichin 60cm-200cm of unsaturated soi l reductions in nitrate co ncentration I Om depch (Gerritse et al., I 995; Cromer, 200 I; from a SAS and concluded agricultural Van Cuyk et al., 2001 ). Table I provides a practices contribute the bulk of nutrients to snapshot on average removal efficiencies of waterways. T here was very li ttle key pollutancs in SAS, wh ils t Figure 7 documented evidence of surface and shows the distribucion of faecal groundwater coliforms with depth from SAS in a co ntamination from onsandy soil (Whelan and Parker, - - Red Dennosol site systems in the souch10 - - Yellow Kurosol east Queensland septic 1981). Calcarosol system survey (Beal et al. - - Sodosol Evidence For and Against 2003a). .....('3<!) Sustainable Performance of Is it the poorly I-< Septic Systems ... ls There a <!) maintained septic tanks 0.1 (.) C: Smoking Gun? and subseq uent sol ids ~ carry-over into the trench 0.. Surfacing effluent can lead to the 0.01 8 that results in failure, export of pathogens inro streams, (.) ('3 rather than the inability of presenti ng pocential health risks, 8 the soil to treat and I-< 0.001 including waterborne-disease <!) ..... percolate the effluent? And outbreaks. N itrate contamination of o/) is the surprisingly common C: gro undwaters and nurrienc 0 0.0001 practice of discharging enrichmenc of receiving surface ....l 20 40 60 80 100 120 0 eff1 uent in to streams, waters are also poten tial impacts. Biomat resistance, Rb, (days) gutcers and drains Qelliffe Nitrate has been detected at high et al., I 995; Beal et al. , co ncentrations in sandy aquifers 2003a) making the greatest Figure 5. Influence of biomat zone resistance on long term below non-sewered areas in the contribution co OWTSacceptance rate for some Australian soils (Beal el al. 20036). Un ited Scates (Robenson et al.,

24 FEBRUARY 2005 water

199 I) although evidence of direct surface water contamination from fail ing SAS is more ambiguous. Nicrogen export from OWTS via groundwater pathways has been predicted to contribute up to 20% (-2 0 t/yr) of the overall nitrogen catchment load in the Pine Rivers Shire, Queensland (Neumann et al., 2004). T here was a case in 1997 where over 400 people contracted Hepatitis A from eating sewage-contaminated oysters from Wallis Lake (Ryan v Great Lakes Council, 1999). The source of che con tamination was not directly from a failing SAS, but reported to be from a caravan site discharging septic tank effluent directly into Wallis Lake. This incident triggered the for mation of the Septic Safe programme, co-ordinated by che NSW Department of Local Government, which has fund ed hundreds of projects aiming to improve research and management ofOWTS. To dare, a few

refereed paper


f,.

Figure 6. Examples of surface surcharging of septic tank effluent due to hydraulically failing septic absorption system.

related water quality impacts? To dare, no 'smo king gun' of poor water quali ty from non-sewered catchments have been clearly identified. However, absence of evidence is not evidence of absence. There remains a gap between desk top studies/circumstantial evidence and actual field measurement. Further, distinguishing animal from hu man -sourced pathogens, using methods like faecal sterol markers (Leeming et al., 1996), needs to be incorporated into field measurement. Th is wi ll help el iminate ambiguity surrounding the nature and extent of impacts from OWTS.

Sustainable Management of Septic Absorption Systems

uniform application , which has been repeatedly demonstrated to improve the performance and lifetime of the trenches by creating an even biomar zone and regul ating peak flows. The increasing trend is to address the issue of setback distances and lot densities based on a risk management protocols. For example, research is underway in th e Sydney Catchment (Charles et al., 2003) and Queensland (Carroll et al., 2004) co develop risk-based OWT S management models. An allotment-scale Development Assessment Model (DAM) has been developed for the Sydney Catchment Authority (McGuiness and Martens, 2003) to facilitate their decision-making on nonsewered allotment size and location of the on-site system. The O nsite Sewage Risk Assessment System (OSRAS) (Department of Loca l Government, 2001 ) is a catchment-scale model char identifi es the areas at greatest risk an d therefore directing management to these ' hotspot' areas (Figure

Th e density of systems in non-sewered subd ivisions can be controlled by Local Auth orities through the planning process. A key factor in sustain able OWTS management is provi d ing sufficient lot area for pollution reduction. This means increas ing lot size and thus reducing the 8) . densities of allotments in non-sewered subdivisions. Therefore a co mp romise is required between sustainabl e OWTS d_ensiries and eco nomic return fo r 1.15 x 10' Collfonne per 100 ml Ellll*lt subd ivision developers - never an easy lllonllll balancing act. 0 Regulations for setback distances from 0.1 waterbodies, boundaries etc are explicit in state OWTS guidel ines, buc not the 0.2 Australian Sta ndard. Beavers and 0.3 Gard ner ( 1993) developed a model to calculate setback distances based on virus ~!t o.4 travel times in th e groundwater. Jelliffe ( 1998) suggested that setback distances to 0.5 <10 contain surface exporcs should vary with 0.6 soil rype and the target receiving water <10 quality objectives, and proposed a 0.7 relatively simple biophysical model to 0.8 L,.,;: <-'-' 10' - - - ' - - - - ~ - - ~ - - - - calculate sufficient nutrient assimilation 0 1 2 3 4 area. The answer to sustainable SAS may Faocal Coliforms per gram (wet weight) x 10' be very simple: fil ters and pumps! Figure 7. The distribution of faeca l coliforms Installation of septic tank fil ters prevent solids carry-over to the trench. Pressure with depth from SAS in a sandy soil based on dosing effluent into trenches will allow (adapted from Whelan and Parker, 1981 ).

refereed paper

Areas of Current and Future Research to Improve Sustainability of Septic Systems The development of th e biomat zone and its interaction with rhe unsaturated soil in hydraulic and treatment fun ction has yer to be fully recognised. Specifically, lateral flow of efflu ent and its relationship wi th bi omat zone height and saturated hydraulic conductivity of rhe A horizon. Modell ing SAS using Hydrus-2D can provide signi ficant insight into the hydraulic pathways in SAS and prediction of surcharge events (Beal et al. , 2004) .

The Authors Cara Beal is Coastal CRC postgraduate student at the University of Queensland, Sc Lucia Qld 4073 and Coastal CRC, www. coastal.crc.org.au, Email c.bea l@uq. edu.au; Ted Gardner is Principal Scientist at the Qld DNRM, Adjunct Associate Pro fessor, Uni versi ty of Queensland and Coastal CRC, Email ted.gardn er@nrm.qld.gov.a u; Neal Menzies is Associate Professor, Schoo l of Land and Food Sciences, University of Queensland, St Lucia Qld 4072, Email n.menzies@uq.edu.au

References Beal C D , Gardner EA, C hristiansen C, Beavers P (2003a) 'A review of on-site wastewater management practices in SEQ local governme nt authorities.' T ask I of 'Audit of no n-sewered areas in south-east Queensland ' report prepared by Queensland Departme nt of Natural Resources and Mines for Moreton Bay Waterways & Catchme nt Partners hip, Brisbane, D ecember 2003. Beal C D , Gardner EA, Menzies NW, Rassam OW, Vieri tz AM (2004) Prediction of steady-state Aux through variably saturated zones within a septic absorption trench. In ' Proceedings of the In ternational Soil Science C onference 2004, 5 - 9 D ecember 2004, Sydney, Auscralia.' Beal C D, Gardne r EA, Vieritz AM, Menzies NW (2003b) Can we predict fa ilure of septic cank- soil absorption systems> A review of their hydrology and biogeochemiscry. In

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FEBRUARY 2005 25


Table 1. A snapshot on average removal efficiencies of key pollutants in septic absorption syste ms . Effluent pollutant

Treatment efficiency

Reference

Pathoge ns

>99% bacteria and 2-3 log virus reduction in 60-90cm soil

[Von Cuyk et

Nutrients

Almost complete nitrification <20cm soil.

(Gerritse et

83% P removal in-75cm unsaturated sand

(Pell and Nyberg, 1989)

91 % COD removal in 15cm unsatura ted sand

(Pell and Nyberg, 1989)

Organics

' P roceedings of On-sire '03 Conference Furure directions for on-sire systems: Best management practices'. Armidale, NSW. (Ed. RA Pat terson) pp. 69-76. (Lanfax Laborarories) Beavers PD, Gardner EA ( 1993) Pred iction of virus transport through soi ls. In ' 15th AWWA Federal Convention, Gold C oasr Q LD,' pp. 530-535. (A WWA Canberra ACT ) Bouma J (1975) Unsamrared flow during soil rrearmenr of septic tank efflu enr. journal of Environmental Engineering, 967-981. Carroll SP, Goonerilleke A, Hargreaves M (2004) Assessmen t of environmental and public health risk of on-sire wasrewarer treatment systems. In 'Proceed ings of the Tenth National Symposium on Individual and Small Community Sewage Systems' . Sacramento, CA pp. 368-376. (ASAE, Sr Joseph, USA) Charles K, Roser D, Ashbolr N, Deere D, McGuinness R (2003) Buffer distances for o n-site sewage systems in Sydney's drinking warer catchments. Water Science and Technology47, 183- 189. Crites RW, Tchobanoglous G (1998) 'Small and decentralized wasrewarer management systems.' (WCB/McGraw-Hill) Cromer WC (200 I) T reating domestic wastewater in a shallow coastal sand aquifer near Hobart. In ' Proceedings of On-sire 'OI Conference'. University of New England, Armidale, NSW pp. 113-120. (Lanfax Laboratories) D awes L, Goonerilleke A (2003) An investigation into rhe role of sire a nd soil

al., 2004) al., 1995)

unsewered areas. In 'Australian Water and Wasrewarer Association Federal Convent ion, 16th, 2- 6 Apr 1995, Sydney NSW, Proceedings' pp. 85-90. (Aust ralian Water and Wasrewarer Association Arrarmon NSW I 995 2 ISBN 064623091 3) Leem ing R, Ball A, Ashbolr NJ, Nichols PD (1996) Using faecal srerols from humans and animals to distinguish faecal pollution in receiving waters. Water Research 30, 28932900. McCardcll A, Davison L (2003) Greywarer arrenuarion in a basaltic soil. In 'Proceedings of On-sire ' 03 Conference'. Armidale NSW. (Lanfax Laboratories) McGuinness, R. l. and D. M . Martens (2003). GIS-based model to assess potential risk of intlividuaf on-site effluent management systems - development assessment motf/1.le (DAM). Proceedings of On-sire '03 Conference: Future directions for on-sire systems-Best management practice, Universiry of New England, Armidale, NSW, Lanfax Laboratories. Neumann L, Gardner EA, Claridge J, Vierirz AJ\11 , Baisden J, Beal CD, Beave rs P, Christiansen C (2004) ' Inicial mass balance assessment on non-sewered areas.' DRAFT prepared by Q ld. Dept. Namral Resources, Mines and Energy for Moreton Bay Waterways and Catchment Partnership, Sepe, 2004.

Pell, M. and F. Nyberg (I 989). "Infilrrarion of wasrewarer in a newly srarred pilot sand-fil ter system: I. Reduction of organic matter and phosphorus." j Environ Qua/ 18: 451-457 . Robertson WO, Cherry JA, Sud icky EA ( I 991) Ground-warer conraminarion from rwo small septic systems on sand aquifers. Gro/1.nd Water 29, 82-92 . Ryan v Grear Lakes Council (1999) Federal Court of Australia, 177 (5 M arch 1999). US EPA (I 997) ' Response to Congress On Use of Decentralized Wastewater Treatment Systems. USEPA publication EPA/832/R97/00 I b. U.S. Environmental Protecrion Agency, Office ofWarer, Washington, DC.' USEPA (2002) ' Onsi ce wastewater rrearmenr systems manual.' Office of Research and Development, US Environmental Protection Agency EPA/625/R-00/008, February. Van C uyk S, Siegrist R, Logan A, Masson S, Fischer E, Figueroa L (200 1) H ydraulic and purification behaviours and their inreracrions during wastewater treatment in soil infi ltration systems. i\1/ater Research 35, 953-964. Van Cuyk, S., R. L. Siegrist, er al. (2004). "Evaluating microbial purification during soil treatment of wastewater with multicomponent rracer and surrogate rests." journal of Environmental Quality 33: 316-329. Whelan BR, Parker WF (l 98 1) Bacterial a nd chem ical transmission th rough sand: a field s mdy in groundwater pollution form a septic rank in Penh, Wesrern Australia. In 'G roundwa ter resources of the Swan Coastal Plain' . (Ed. BR Whelan) pp. 313-333. (CS IRO Ausr. Perth) Whitehead JH, G ea ry PM (2000) Geocechn ical aspects of domestic on-site effluent management systems. Australian journal of Earth Sciences 47, 75-82.

On-Site Sewage Export Hazard Class

characrerisrics in o nsire sewage trearn, enr.

Environmental Geology 44, 467-477. Department of Local Government (200 1) 'Onsire sewage risk assessment system handbook (Consulrarion Draft).' (Developed by Brown & Root Services Asia Pacific Pry Ltd for the NSW Department of Local Government ISBN 1 87621 19 1) Geary PM (2004) On-sire domestic system effluent tracing in a coastal carchmenr. In 'T enth National Symposium on Ind ividual and Small Commun ity Sewage Systems'. March 21-24, Sacramento, C alifornia. (Ed. KR Mankin) pp . 722-732. (ASAE, Sr Joseph, Michigan) Gerrirse RG, Adeney JA, Hosking J (1995) Nitrogen losses from a domestic septic rank system on rhe Darling Plateau in Western Ausrralia. Water Research 29, 2055-2058. Jelliffe PA (1998) Predicting stormwarer quality from unsewered development. Waterfall Uournal ofthe Stormwater Industry Association) 9, 19-24. Jelli ffe PA, Sabburg G, Wolff J (1995) Key factors in minimising warer pollution fro m

26 FEBRUARY

2005

water

Qt!.SITf ~fl:l'.A!:,:f f;!'.PQB! ~

I I I

!i SEVERE HAZNlO

4 liK:HKA.ZAAO

3 MOOlRAIEHAZAAO 2 MIUORHA.Z>R) l l!lll[ HAZARD

D D

RETICUlAfCOWAttR AAEABCtJt-llAY SE'lttRED AREA

TU ROSS ESTUARY CASE STUDY

FlgureC.S OU-SITE SEWAGE EXPORT H~RO CLASS llrljfO.iLl,~l.l'l',I ~I.VrJI

Figure 8. Example of OSRAS graph ical output fo r on-site sewage export hazard class the for Tuross Estuary case study (Department of Local Government, 2001).

refereed paper


IMPACTS OF SEWAGE OVERFLOWS ON AN URBAN CREEK P Pollard, R Leeming, S Bagraith, M Greenway, N Ashbolt Abstract The Coastal CRC has been working with Brisbane City Council to determine rhe impacts of sewage overAows and risks to public and ecosys tem health in a pilot study of the tidal waterways of the coastal suburb of Lora. The research shows in a large wet weather event, srormwarer and nor the overAow was rhe dom inant srressor of ecological health. Even in a dry weather overAow event impacts were low and restri cted to rhe mixing zone at rhe point of overA ow. However, sewage overAows, both in dry and wet weather, did pose an unacceptably high public health haza rd to poss ible swimmers in Lo ra Creek un ti l the ove rAow stopped and there was a complete tidal exchange wirh rhe esruary. Despite being an intensive study of a single wet weather event there is sufficient dara for it to be translated to sim ilar ridal environments, and has provided a sound scientific basis for quantifying overflow impacts and priori rising management of overAows and sto rmwarer.

Background Sewerage sys tems in Australia are des igned with overA ow structures that discharge into local waterways when rhe capacity of the sys tem is exceeded. A dry weather overflow occurs when there is a system breakdown due to blockages or a pump failure. Wet weather overAows are mainl y caused by rh e infiltration of water into the sewerage syste m during heavy rainfall to a point where the hydraulic capacity of rhe system is exceeded. Hal f of the sewer pipes in Brisbane are on pri vate property and water enters the sewer through rhe illegal connection of roof an d stormwater drains (inAows) . Brisbane Ciry Council (BCC) manages rhe main network where water also enters through poo rly sealed access chambers, cracked pipes and defective joints (infiltration). T he public generally is unaware of overAows, their purpose or function nor rhe exte nt of rhe urban catchment run-off. However, they are acutely aware of rh e gross pollutants associated with them. The appearance of sewage and litter in our ri vers during heavy rain can stir rhe emotions of even the most placid of Brisbane Ciry

refereed paper

Figure l. The seven overflow structures in the study area (Planning Un it LT/010) are shown in the numbered yellow circles. The circled numbers represent the codes used to identify the overflow structures (0/F = Overflow; SP = Sewage pump station) . Due to heavy rai n (60 mm.d¡1 on 15 May 2003) sewage filled the wet well at SP 20. It backed up behind SP20 a nd overflowed at 0/F 717. T shows manual sampling sites, 'A' shows autosampler sites .

dwellers, as on the aesthetics of rhe receivi ng waters is obvious. However, nutrients, pathogens, organic toxicanrs and metals also enter the waterway during an overAow event. T he aim of chis research was to quantify rhe ecological an d public hea lth impacts and potential risks of sewage overAows in rhe Lora Creek catchm ent area (including Bowering Srreer tributary).

OverAow monitors were installed in all overAow srrucrures with alerts at SP 20 and 0 F 7 17 as described by Millar et al. (2002). Samples were co llected manually from seven si res and by autosamplers from two sires in fou r situations: 1. Ambient dry weather event: No rain or overflow in the srudy area. Samples taken at high and low ride.

Stormwater and not the overflow was the dominant stressor of ecological health, but any overflow posed an unacceptably high public health hazard to possible swimmers. Study Approach The study was conducted in rhe lower Lora catchment waterways. T here are seven overAow srrucrures in rhe study area (Planning Unit LT/O lO)(Figure 1).

2. Dry weather with overflow event: Equipment failure as rhe only cause of overAow. 3. Wet weather with overflow event: Water infiltration of sewerage network was rhe only cause of overAow.

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FEBRUARY 2005 27


Table 1.

Research* summary. Observation

Concern Ambient Dry Weather No Overflow

Stormwater Run-off No Overflow

Wet Weather with Overflow

Dry Weather with Overflow

Risk to public health from human enteric bacteria and viruses

None

Faecal coliforms hig h but low risk from human faecal contamination

Unsafe for recreation during overflow, even though 80% of the foecal coliform count was due to stormwoter run-off and was not of human orig in

Extremely high as na stormwoter or in-pipe di lution

Loss of amenity for recreational activities

None

Faecal coliforms high but low risk from human faecal contam ination

High during overflow

Extremely high

Impacts of increased turbidity, nutrients: nitrogen, phosphorus ond dissolved organic carbon and to the water column

None

Unacceptably High

Low and restricted lo point of release, stormwoter run-off was the main contributor

Low and confined to BST close lo point al release

Reduced oxygen concentrations in the water column

Low in some locations

Low in some locations

Not reduced: physical re-aeration rates of the water column were greater than microbial respira tion rates

Little reduction: physical re-aeration ra tes of the waler column were greater than microbial respiration rotes

Adding hormones disruptors to the water column

Not measured

Inconclusive (below detection limit)

Below detection limit however based on hydrological dilution may have impact in BST

Based on hydrological dilution may have impact

Add ing metals to the water column

None

N ot measured

Below trigger values for aquatic ecosystem health

Low and localised, dilution puts all below trigger values outside BST

Likely cumulative effects

None

Low based on dry weather re-suspension of sediments

Low based on dry weather re-suspension of sediments

Low based on dry weather re-suspension of sediments

Public Health

Ecosystem Health

Toxicants

*Stormwater impacts were only related to contaminants found in the untreated sewage overflow BST = Bowering Street tributary Enteric = of the intestine Faecal coliform = Thermotolerant coliform

4. Wet weather without overflow event: Stormwater not influenced by overflow effluent during a rain event normally large enough co cause a wee weather overflow. We characterised the pollutants in the sewage of Lota to determine its physical, chem ical, toxicological and microbiological character (Pollard and Chapman, 2002). T he analyces included: organic and inorganic nu trients, srerol biomarkers, microbial faecal ind icators, pathogens indicators (bacteria, viruses, protozoa), toxicants, 69 metals, exotic chemicals, radioisotopes and endocrine disrupcers. Although rhe project was not a scudy of the srormwarer impacts, we looked for the pollutants common to both to distingu ish the impacts of che overflow during che wetweather event. T he next stage of the proj ect determined the ambient (normal) water-qual ity of Lora's waterways in relation to the pollutants fo und in che untreated sewage. This was the most cost-effective approach.

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FEBRUARY 2005

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CSIRO Mathematics and Information Service designed a sampling strategy based on rhe 'Weigh t of evidence' for dry and wet-weather sampling (Harch and Toscas, 2002). As wet-weather events were infrequent (one in two years), repetitive event sampling was not possible. The seven overflow struccures were monitored fo r rwo years. Of these, six had no impact on the local waterway because they did not overflow. Pathogen indicator analysis is expensive. We found the most cost-effective approach was to test samples for faecal coliform contamination duri ng the event at all locations and times. Faecal coliform (thermoro lerant coliform) rests were completed within 10 h to identify areas of greatest contamination. The more expensive and time-consuming analyses, such as human sterols, enterococci, cfostridium and coliphage were then used as confirmation tests for the presence of human faecal contamination.

Knowing the ambient water-quality of the receiving waterway, we were able to compare cha nges caused by rhe overflow events. Human faecal contamination in the waterway was used to assess che public health hazard and potential risk assessment based on pathogenic indicato rs and human srerol biomarkers. Quantitative risk assessment (QRA) was then based on the WHO (2003) microbial water-quality guidelines. The enterococci abundance was then used in che risk assessment model to determine potential human public health risks. Risk assessment requires knowledge of the extent of human exposure, such as in swimming. While we observed ch ildren swimming and canoeing in the scudy area, a quantitative assessment of the use (exposure to hazard) of the waterway was beyond the scope of this study. Two different systems were used for assessing public and ecosystem health impacts. The dose-response research for

refereed paper


QRA is well advanced compared to that of ecosystem health assessment. Hence the publ ic health hazard is well quantified and based on key pathogen surrogates. However, to carry out dose-response studies for assessing ecosystem health would require waterways to be dosed with a range of pollutants to assess their impacts. Conseq uently we co mpared changes to ambient physical and chem ical co nditions caused by the overflow and pollutants exceeding trigger values recommended by ANZECC (2000) and BCC water-quality guidelines and obj ectives for aq uatic ecosystem protection. This study took into acco unt dry- and wet-weather overflows focusing on the potential impacts and hazards. Table I summarises the concerns and observations from the research.

Tidal Prism The tidal prism was 2.6 ML (neap tide) 5.6 (sp ring tides) fo r the Bowering Street tributary. Details of the hydrological tidal influence are described by Hargraves (2002), as part of the urban rainfall run-off model task of the project. Overflow Events T h e cause of the dry overflow was equipment failure on 4 June 2002. Sewage entered the Bowering Street tributary (BST) at a rate of approximately 65 m3.h¡ 1 for 5 h (0.33 ML). T he overflow coincided with the falling tide in the receiving waters of BST. The sewage was diluted 1:6 with the tributary water at the overflow site. The first obvious sign of uncreated sewage was toilet paper caught in the vegetation on in the waterway, an obvious loss of rhe visual amen icy (Figure 2) . The wet weather overflow occurred on 15 May 2003 because of a rainfall event of 60 mm over 12 h. Untreated sewage (l. l ML) overflowed into the SST and Lota Cree k for 36 h where it mixed with 53 ML of scormwater run-off. A ' mixing zone' imm ed iately in front of the overflow structure was difficult to defin e because of tidal movement. This study showed the plume of untreated sewage did nor readily disperse in the receiving environment. T he sewage had been diluted by inflow and infiltration 1:3 in the sewer at the start of the overflow and this increased to 1:6. The dilution rate of the untreated sewage varied as it entered the BST from l % to 5.5% (v/v) on 15 May 2003. Stormwater was the predominant dilution factor as the tide contributed only 10% (v/v) of the dilution.

Public Health Risks Microbial Water Quality Assessment Details of the microbial water quality resul rs can be found in the reports by

refereed paper

Figure 2. Picture of untreated sewage leaving the overflow structure (O/F 7 17 ) shows the impact on visual recreation quality. ("They are notes, Ma'am, that say DO N OT SWIM HERE" Charles Dickens). Pollard and Leeming, 2002; 2003; Pollard et al., 2004. Generally, during both the dry and wet weather overflow event the faecal indicators (faecal co liform, E. coli, Clostridiurn, enterococci and coliphage) increased several orde rs of magnitude above public health guidelines for primary contact (swimming) . Based on measurements of the human sterol biomarker all of the faecal contam ination was of hu man origin during the dry-weather overflow event (Fi gure 3). During the wet weather event, sto rmwater co ntributed 80% of these indicators; only 20% being of human origin (Figure 4 a, b and c) . However, the unacceptably high public health haza rd remai ned during the wet weather overflow despite the dilution due to the rain. T he dry and wet weather overflows produced a sewage plume that did not readily mix with seawater. The risk to public health was of greatest concern fol lowing the initial overflow. For areas affected the unacceptably high risk to potential swimmers and loss of the recreation amenity pers isted until the overflow stopped and there were one to two complete tidal exchanges. T he plume contaminants were exported beyond the limits of Lora Creek Study area into Moreton Bay (Fig and 4) . Water quality guidelines are often based on pathogen indicators th at cannot separate human faeca l con tamination from other warm-blooded animals. Hence stormwacer run-off often causes waterways and coastl in es to exceed these standards (Nobel et al., 2003) and in tropical waters may result from growth and erosion of faecal coli forms (thermotolerant coliforms) and encerococci in soils (Fujioka et al., 1999). We found that much of these breaches may not be due to human faecal matter based

on human sterol analysis. During a wet weather sewage overflow a lesser pub lic health hazard remains from potential bacterial, viral and parasitic protozoa pathogens compared to a dry weather event. Quantitative Microbial Risk Assessment (QMRA) QMRA is a mea ns of identi fying a potential public health risk. Fo r Lora Creek the risks are to recreational swim mers and people eating shell fish (although harvesting is not known in the study area). QMRA identifies the gro ups most at risk and defines the pathways. The selected reference pathogens suggested for the Lora Creek study showed viral risks were highest, as previously seen for Sydney's coastal beaches (Ashbolt eta!. 1997) . To provide a 'second opinion' on the risk es timates, an estimate of potential disease was obtained by assuming char on ly 20% of rhe enrerococci in the bath ing waters came directly from sewage (the primary material expected to con rain in fect ious human enreric viruses during a wet weather event). T his was based on the human sterol work that showed most of the pathogen indicators were not of human origin. This gave expected risks in the range of 10% to 100% indicating rhe waterway was unsuitable for recreation for at least the duration of the overflow (36 h) with a furth er 24 h before the waterway retu rned to background levels of contami nation. For rhe dry weather event this unacceptably high risk would have persisted for, during and 12 h after the overflow had stopped. Boch approaches suggest char the risks to bathers during overflow events BOTH during high rainfall and in dry weather should be co nsidered unacceptably high. As

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FEBRUARY 2005 29


Table 2. Five key micro bial wate r quality parameters for fu ture mo nitoring p rog ram s. Parameter

* Faecal

coliform/ E. co/i 1

Essential

Remarks

Yes

Most practical and cost-effective way to track plume. Used to identify 'hot spots' which con be followe d up by confirmation test of parameters below.

Enterococci

Yes

Basis of WHO (2003) guidelines and QMRA

Coliphoge

Yes/N o

Used to model the highest risk category - viral pathogen survival and likely to be in future guidelines.

Human sterols (Biomarkers)

Yes/No

Essential in wet weather to determine human proportion of sewage mi xed with stormwoter run-off.

Clostridium

No

Useful as more robust indicator of faecal pollution over long periods.

* Same as Thermotolerant coli forms

1. Ashbolt et al., 2001

an early management action, signs should be erected to warn swimmers of risks during overflow periods. T he areas most affected are the Bowering Street tributary, lower reaches of Lota Creek and in to Moreton Bay (depend ing on the d irection of the sewage plume) . How far the plume extended and persisted as a potential hazard in Moreton Bay and the bathing area at Wynnum and Manly was beyond the scope of chis study, but warrants investigation (Figures 3 and 4).

Ecological Health Derails of the abiocic water quality can be fou nd in Pollard and Leemi ng, 2002; 2003; Pollard et al., 2004. Figure 5 shows a conceptual model of the ecological processes in Lora Creek. During the wet weather overflow event, inorganic (e.g. nitrogen and phosphorus) and organic nutrients and suspended solids in the overflow effl uent were rapidly diluted in the sewerage network and the waterway. Concentrations were either below those associated with a healthy aquatic ecosystem and/or below those of the stormwater concentrations. Possible adverse impacts of chemical and physical stressors on ecosystem hea lth were due primarily to stormwater run-off and not the overflow. Dissolved oxygen (DO) concentrations in the water column are often the basis of judging ecosystem health. As DO is ulti mately governed by the growth rates of heterotrophic bacteria, we were interested in their abundance and growth. Lota C reek and the Bowering Street tributary had high numbers of bacteria and viruses with the bacteria growing extremely rap idly compared to ambient (normal) conditions. In wet and dry weather overflows increased hererotroph ic bacterial growth rates in the waterways were above amb ient concentrations. This growth parameter was the fi rst to demonstrate an influence of the overflow effl uent on biological processes in the waterway. Despite this, there was no deterioration in the water colu mn 's dissolved oxygen due to rhe overflow event. T he rare of physical re-aeration of the water column was mostly greater rhan the rate at which the bacteria used the DO . During the dry-weather overflow nitrogen and phosphorus, in the Bowering Street tributary below the overflow, were at concentrations IO fo ld higher than the water quality objectives of BCC. H owever, once these nutrients reached Lota Creek, they were diluted by more than a factor of I 00 and ap proached the ambient water quality concentrations and objective of BCC for Lora Creek and the ANZECC (2000) guidel ines. Overall, the water quality changes were confined to the period of the overflow within 500 rn of the overflow structure with little changes to the dissolved oxygen co ncen trations due to the overflow itself. The Lota Creek and Bowering Street tributary results suggest that rhe ecological health of ocher tidally exchanged creeks can be

30

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determined in part by measuring the rate of the physical re-aeration of the water column and the rate of sewage dilution. These need to be in conjunction with a knowledge of the nutrient-loading rate in the waterway that could potentially drive the heterorro phic bacterial growth rates in the sewage to extremes. Some metals (aluminium, copper and zinc) were of concern in rhe sewage before dilution. However, the co mbined in-p ipe and sto rmwater dilution left them below ANZECC trigger values in wet-weather. Escrogen ic hormones were found in the undiluted sewage and were moni to red in the waterways of rhis study. However, rhey were below the detection limit of the assay i.e. 5 ng. 1-1• T he di lution of the estrone in rhe un created sewage suggested rhe concentrations could have ranged fro m 0. 1 to 2 ng. L· 1 in Bowering Street trib utary in the wet and <5 ng. L· 1 in rhe dry weather overflow event. In these ranges estrogenic hormones may be biologically active in aquatic environments (A nderso n et al. , 2004) . In Syd ney and Perth research on rhe impacts of sewage overflows (Sydney Water, 1998; Water Corporation Penh (2003) citing DA Lord (1997)) showed the loss of recreation ameni ty outweighed the potential risk to ecological health, just as we found in chis Lora scudy. Others have also separated health impacts an d risks from chose of the stormwater ro fi nd also chat the risks to ecological health were often the resul t of sto rmwacer rather than sewage overflows (Bickfo rd et al., 1999).

1.000.000 cfu.100mL 500,000 cfu.100ml 100,000 cfu.100mL

Bay

?

/ ?

Limt J

Study Area,

Figure 3. Fa ecal coliform (cfu. l OOmL-1) a t the time of peak sewage overflow du ring the dry weather event 4 June 2002) . The public hea lth risk re ma ined unacceptably high during and 12 h after the overflow had stopped. The movement of the sewage plume into Mo reton Bay needs investiga ting . (MAP).

refereed paper


Implications for Other Tidal Estuaries

health, while the overflow is respons ible for the public health hazard and loss of

We found that the important factors to cons ider for determining ecological healrh in other tidally exchanged creeks are rhe race of the physical re-aeration of the water column, rhe hydrological in-pipe and stormwarer di luti on in co njunction with the nutrient-loading rate. A waterway 'I ndex' could be developed to co mpare hydrological characteristics and water column re-aera tion rates of Lota Creek to ocher tidally influenced creeks in Brisbane. Th is would allow extrapolation of Lora C reek findings to ocher waterway co ntamin ants and provide insight to pote n tial management options and help priori tise creeks fo r overflow abatement.

recreation amenity. Environmental concern fo r waterway pollution should sh ift from sewage to sto rmwarer for, as we have shown, srormwacer is the chief source of environmental pollu tion during wetweather overflows.

Future Direction and Conclusions T he greatest gap in our knowledge of the waterways in the study was of the exten t of hu man exposure to the public health hazard . This inform ation is essenti al for the final risk-assessment and should fo rm the bas is of a larger risk management fram ework. With chis informa tion, che knowledge gained here of rhe hydrological dilutio n of che untreated sewage ca n be used co predict the public and ecosystem health risks of ocher similar tidally influ enced coastal environments in Brisbane. Fro m ch is study we learnt ch e most-cost effective and practical way co mon itor the sewage overflow plume was to fo ll ow its movement in rime and space, while assessing the public health hazard based on WHO (2003) Microbiological Water Q uality Guidelines. Tab le 2 lists fi ve key param eters, not all are essential in future monitori ng programs. lf the community wants to increase recreational am enity in Lota Creek, future resea rch could foc us on developing methods that optimise rapid pathogen removal at th e overflow structure. (Long-term management cou ld consider methods to red uce the use of water and pipe nerworks co carry domestic waste co large wastewater treatment planes). However, while che sewer pipe networks exist, emergency sewage overflows will remai n pare of the sewerage system. T hey are an emotive issue for the public but che concern needs to be well fo unded and properly directed. Th is study has shown char stormwater should be of much greater concern fo r ecosystem

refereed paper

Acknowledgements We tha nk Dr Roger Shaw (Coastal CRC), Pier Filer and Fiona Cha ndler (B risbane City Council) for their co ntribution co rhe project. We are particularly indebted co Grant Millar (Nacu ral Resources and Mines) and Alan Geri cz (AG Enviro) fo r developing, maintai ning and monicoring rhe field instrum ents, and to Peter Pollard's poscdoccoral fellows, resea rch assistants and postgraduate students (the Tactical Response Team) Eloise Larsen, Melissa Wos, Michelle Jones, Darren Carso nT aylor, Scott Moffatt, Mark Page, Steph en Tucker, Heather Uwins and Jill Alroe who had co turn out at shore notice to sample che ephemeral events. Their generosity, dedication and enth usiasm made this scudy possible.

The Authors Dr Peter Pollard (p.pollard@griffith.edu.au} is a senior research fellow at Griffith University, program leader for Ecosystem Heal th Assessment in che Centre for Riverine Landscapes, and leader of the Coastal CRC's sewage overflow abatement project;

Ass Prof Margaret Greenway is Associate Professor in the School of Environmental Engi neering, Griffith Universiry, Nathan Q ueensland 411 1; Dr Rhys Leeming is Environmental Biochemist at CSIRO Marine Research, Castray Esplanade Hobart, T asmania 7000; Sam Bagraith is Manager Sewage Overflow Abatement Program, Brisbane Water, T C Beirne Building, Fo rtitude Valley, Brisbane Q ueensland 4006; and Prof Nicholas Ashbolt is Professor in che School of Civil and Environmental Engineering, The University of New South Wales, Sydney NSW 2052. References Anderson, P.D., D'Aco, V.J., Shanahan, P., Chapra, S.C., Buzby, M.E., C unningham, V.J., Duplessie, B.M., Hayes, E.P., Mastroccooo, F.J ., Parke, N .J ., Rader, J.C., Samuelian, J.H. and P.W. Schwab. (2004) Screening analysis of human pharmaceutical compounds in U.S. surface waters.

Environmental Science and Technology 38:838-849. ANZECC (2000) . Australian and New Zealand Guidel ines for Fresh and Marine Water Quality - Volume I, The Guidel ines. Austra lian and New Zealand Environmen t and Conservatio n Council, and Agriculture and Resource M anagement Cou ncil of Austral ia ad New Zealand. In 'National Water Quality Managemenr Strategy; No

4'. Ashbolt, N.J., C. Reidy and C.N. Haas ( I 997). Microbial health risk at Sydney' s coastal bathing beaches. In: Proc. 17th Australian \'(/atcr and Wastewater Association meeting, 16-2 1 March, 1997, Melbourne. Vol. 2. AWWA, Melbou rne, pp:104-111 .

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Inorganic nutrients

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Figure 5. A conceptual biological model of the ecological processes in Lota Creek and Bowering Street tributary during a wet weather overflow event. Stormwater run-off was the dominant influence of ecosystem processes and its health in wet weather.

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Figure 4. During the wet wea ther overflow the potential public health ri sks we re unacceptable even though most (80%) of the faecal coliform count was associated wi th the stormwater runoff and was not of human origin. The distribution of faecal col iforms (CFU. l 00m L·1) during the overflow o n 15 May 2003; morning (A), late afternoon (B) and on 16 May 2003 in the evening (C) is shown. The sewage plume moved into Moreton Bay and these impacts need investigating.

Ashbolc, N.J., Grabow, W.O.K. and Snozzi, M . (2001) Indicators of microbial water quality. ln Fewcrell , L. and Bartram, J. (Eds.), Water

Quality: Guidelines, Standards and Health. Risk assessment and management for water-related infectiow disease, C hapter 13: 289-3 l 5. London: ]WA Publishing. BCC WQO (2000). Guideline on the identification and Applying Water Quality Objectives in Brisbane City. Version 1 March 2000. Prepared by Waterways Program Urban Management Division of Brisbane C iry Council Bickford, G., T oll, T ., Hansen, J., Baker, E. and R. Keessen. (l 999) Aquatic ecological and human health risk assessment of chemicals in wet weather d ischarges in the Sydney region , New South Wales Australia. Marine Pollution Bulletin, 39( 1- 12) : 335-345.

32 FEBRUARY 2005

water

Fujioka, R. , Sian-D enton, C., Bo rja, M ., Castro, J. and Morphew, K. ( 1999) Soil: the environmental source of Escherichia coli and enterococci in G uam's st reams. journal ofApplied Microbiology Symposium Supplement, 85 (28), 83S-89S. Harch, B. and P. Toscas (2002). Spatial Extent and Temporal Persistence as a Result of Sewage O verflows in Lora Plann ing Unit LT0I0. Coastal C RC Report No . EM2 co Brisbane C ity Council. Pp 15. Hargraves, G . (2002). Rain fa ll Runoff Model for Lota C reek (EM 5). Edited by Peter Pollard. Prepared for the Coastal Zone C RC and Brisbane C iry Council, August 2002 (EM 4.3). pp 28. Millar, G ., Gardner, T., and P. Pollard (2002). 'A summa,y of the Soap Project and a novel system co quantify, monitor and alert of sewage overflows into the receiving waters of the Lota C reek Catchment' Australian Water Associat ion regional Conference. Mooloolaba, 8-10 N ov. 2002 Nobel, R.T., Weisberg, S.B. , Leecasrer, M.K., M cGee, C.D.,Dorsey, J.H., Yainik P. , and V . O rozco-borbon. (2003). Storm effects on regional beach water quality along rhe sourhern C alifornia shorel ine. journal of V(later and Health. 1(l): 23-3 1 Sydney W ater ( 1998) Licensing Sewerage Overflow E nvironmental Impact Statement, Sydney Water Corpo ration, Sydney, NSW, Australia .. www.sydneywacer.com.au. Pollard, P. C. and H . C hapman (2002) . Characterising the Uncreated Sewage of Lora Catchment (EM4 .J ). Prepared for rhe Coastal Zone C RC and Brisbane C ity Council, August 2002 pp 7 1. Pollard, P.C. and R. Leeming (2002) . Ambient W ater Quality of Lora C reek (EM4.2) . Prepared fo r che Coastal Zone C RC and Brisbane C ity C ouncil, pp 109 . Pollard , P.C. and R. Leeming (2003) . Wet W eather Sewage Overflow Abatement Project - Lora C reek Pilot: Dry Weather Overflow (Special report). Prepared fo r the Coastal Zone CRC and Brisbane C ity Council, pp 94. Pollard, P.C., Leeming, R., Bagraith , S., Greenway, M . and N. Ashbolt (2004) . W et Weat her Sewage Overflow Abatement Project - Lota C reek Pilot: Wet Wearher Overflow (EM 4 and 6). P repared for the Coastal Zone CRC and Brisbane C ity Council , pp 220. W ater Corporation Perth 2003 (Perth Metropolitan Area citi ng http: //www.warercorporarion.com.au/environmen t/overflows_report_ final_jan_04.pdf. Citing DA Lord ( 1997) . Effects of Sewer O verflows o the Swan and Canning River Trust report n0 97/006/ 1., D.A. Lord and Associates Pry Ltd .; Perth. WHO (2003). C hapter 4. Faecal Pollution and Water Quality. Guidelines

for Safa Recreational Water Environments. Vol. 1: Coastal and Fresh Waters. Geneva, World H ealth Organisation Publishers.

refereed paper


CENTRAL QUEENSLAND'S COASTAL WATERWAYS PUBLIC AWARENESS CAMPAIGN D Alcock Abstract

.•..

T h is case study looks at the effecti veness of a regional 'Healthy Waterways' med ia campaign in rhe Fitzroy Basin in Central Queensland. The three-year television campaign was des igned co co mmunicate how science and co mmunity actions are addressing local catchment and waterway issues.

FITZROY CATCHMENT

Introduction Following a regional co mmun ication planning workshop, the Fitzroy Bas in Association (FBA), Cooperative Research Cen ere for Coastal Zo ne, Estuary and Waterway Management (Coastal CRC), jointly representing 40 government agencies, industry groups and NGOs, agreed co develop a publi c awareness campaign co show how science, management an d community action are addressing catchment and waterway issues in central Q ueensland. T he aims of the cam paign were co: • co m mun icate the nature and extem of the environmental issues and suggest effective actions for catchment sustainab ility. • transfer co the local co mmuni ty the benefi ts of collaborative environmental research. • inform pol icy makers, leaders and res ide nts about natural resource management • prepare the public for changes resulting fro m regional plan ning processes, such as Central Queensland Stra tegy for Susta inability.

Figure 1. The Fitzroy Basin .

WIN Television, the main local commercial broadcaster in the regio n, and included increased news coverage and publicity abou t narnral resource management issues in the region.

Planning the Campaign A local plann ing ream was for med (Alcock, 2004) with representatives from Sunfish , the Departmem of Natural Reso urces and Mines, Rockhampcon City Council, Central Queensland University, Fi tzroy Basin Elders Committee, Departm ent of Primary Industri es, CRC fo r Catchment Hydrology, Fitzroy Basin

Regional television campaigns are a cost-effective coastal management tool to communicate river, catchment and water issues to large audiences. • encourage orga nisati ons and community members co become involved in coastal managemen r acrivities. The campaign comprised of a series of 30 and 60 seco nd information segments on

Association and WIN Television. The Coastal CRC brokered the proposal with local organisations, secured sponsorship fun din g, facilitated planning meetin gs, designed messages and scripts, integrated campaign objectives with local

organ isatio ns, and contribu ted fu nds co the campaign's development. The campaign was planned as a three-year program targeting loca l residents, community leaders, schools, co nservation groups, fis hers, and narn ral resource managers. Approx imately 188,000 people live within ch is vast catchment - Australia's second largest - which includes the townships of Rockhampcon, Emerald, Yeppoon and Gladstone. T he Fitzroy ri ver discharges into the southern lagoon of the G rea r Barrier Reef Marine park (Figure 1). Previous research (Cable and Knudson, 1983) has shown that good com mun ication programs can help shift public support, improve pro-environmental behaviour, red uce pollution, manage visito r numbers, and infl uence policies that affect natural resources. Market research, undertaken by social researchers at Central Queensland University (Lockie and Jennings, 2002), indicated char the mosr widely accessed sou rce of information on waterways by res idents living in the region is television (7 1%), environmental groups (49%) and local newspapers (50%). T his

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FEBRUARY 2005 33


coastal ere result was an important fac tor in selecting television as the primary medium to reach a wide, geographically dispersed audience. Figure 2 shows television to be by fa r the most visible source of information on waterways. Other widely used sources of infor mation were environmental groups, local newspapers and friends and co lleagues. Schools and ed ucation materials, festivals, events and radio were also important sources of in formation by significant numbers of people.

Television Local newspapers Environmental groups Friends or colleagues National newspapers Festivals & events Schools/educational materials Radio

Costs Another advantage of regional television is its cost effectiveness in reaching large numbers of people frequently - particularly when compared to rhe higher production coses and advertising rates in capital cities. Each segment cost $800 to professionally produce (including scripting, travel, filming and edi ting) . Broadcast coses ranged anywhere between $16 fo r early morning spots to $340 in prime time evening spots. T he series was broadcast frequently during 2002 and 2003, averaging 15 to 20 spots per week over eight months, during a variety of viewing programs.

0

10

40

50

60

70

80

Figure 2. Sources of information about water used by CQ residents.

The segments were shown as paid spots (T VAs), bonus spots and as community service spots (placed for free). WJN T elevision sponsorsh ip was generous. In 2002, cash sponsorship was $36,400 and free airtime provided by WIN TV was valued at $40,000. In 2003, the cash inves'tmenc was less - $28,000 and the

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station provided more than $30,000 worth of free airtime. In 2004, cash investment was $24,000 with a similar amount of free airtime. A number of TV news stories were orga nised separately on TV, radio and in local newspapers about water research, education and management projects in the region. In terms of value for money, it was a good deal .

The three stages The first stage (from April to November 2002: 'p ublic awareness' ph ase) promoted the concept of' Healchy Waterways' for local central Queensland, and how science, education, commu ni ty and management programs were addressing water-related issues in the region. The local television weather presenter, Peter Byrne, and the Chair of the Fitzroy Basin Association, Barbara Wild en, launched the campaign in March 2002 at the Gumoo Bullaroo Catchment Conference held in Rockhampton. Eleven information segments were produced and broadcast chat year, in conjunction with regular television, radio and newspapers news features, and through e-newsletters and websires directly to stakeholders. Topics in the first series all repeated the theme 'Central Queensland Healthy Waterways: good for the country, good for you.' TV topics included restoring fish habitat in creeks, providing freshwater flows for barramundi survival, scientific water quality monitoring in the Fitzroy River, Vv'aterwatch community monitoring, revegetatin g riparian areas, volunteer monitoring in Gladstone's port, and Indigenous involvement in natural resource management. The second stage (from April to November 2003: 'public action' phase) outlined more practical ways to improve


the heal ch and co ndition of rivers, catch ments and waterways. The plan ning ream evaluated and reviewed the ca mpaign's first phase, using indicators such as feedback by sponsors, comments by local Landcare and Coastcare groups, reviews from colleagues, and results from an e-mai l survey co catchment coordin ators. Results from the second phase of a Cemral Queensland Heal thy Waterways survey of 800 residents, cond ucted at rhe end of 2002, demonstrated an increased level of awareness abo ut the campaign. After one year, 90% of local residents th roughout th e region we re aware of the ca mpaign and there was an even greater reca ll of individual messages. Positive feedback co the campaign co ntinued co grow. New spo nsors joined in and there was increased anecdotal feedback about how the community was mention ing the campaign's messages in schoo ls, ar fis hing clubs, by govern men t agency staff, at local council meetings, and during Coastal CRC and FBA workshops. T he plan ning ream developed a new series of television segments and radio comm uni ty service advertisements. The ca mpaign was 're-laun ched' at a fu nction involvi ng the Coastal CRC and FBA in Rockham peon in May 2003 with sponsors. New segment top ics produced in 2003 responsible fishing practices, rehab ili tati ng the Dee River, catchment managemem on fa rms, reducing litter and pollution, comrolling river weeds, scientific modell ing of river sediment, and historical changes co coastal landscapes. A third stage (from August to November 2004 : 'collaborative links' phase) featured a series of 12 x 60 seco nd long in form ation

segments and shore interviews with key people. Each segment was ai red once a week during prime rime even ing news. Topics included water sensitive urban design, rhe importance of shallow estuaries fish habitat, barramundi fish managemem, managing sal inity on fa rms, property managemem plans, and codes of practice for water conservation .

Project Benefits - Summary • agreemen t by steering group chat media campaign objectives were achieved • collaboration between project team members, spo nsors and supporti ng organisations • increased public awareness and education abou t catchment and waterway issues • extensive news media coverage of water science and natural resource plan ni ng issues in the region • community support co the co ncept of ' Healthy Waterways' by decisio n-makers in local cou ncils and govern ment agencies, and by farm ers, urban residems and school child ren • increased knowledge of conservation and monitoring programs such as Landcare and Waterwatch and Neighbourhood Catchments. • in creased commu ni ty awareness of major research and natural reso urce management organisations, in particul ar the Coastal CRC and Fitzroy Basin Association. • increasing numbers of local spo nsors becoming involved each yea r

Conclusion Regional television-based media campaigns are a cost effective coastal management coo l to com municate the natu re and extent of river, catchment and

water issues to large audiences. With spo nsorship and support, they can effectively raise awareness, convey scientific and conservation messages, generate support for natural resource managemem initiatives, and even prepare communi ties for social change. It is important to set clear objectives, review all stages of the campaign, recognise the co ntribution of sponsors, and carefully evaluate the costeffectiveness of the project. A selection of Healthy Waterway med ia segments can be downloaded using Rea/player or equivalent, from the Coastal CR.C's website at: www.coascal. crc.org.au/ media/ index.html

The Author

Don Alcock (don .alcock@nrm. qld. gov. au) is a science and environmental comm un ication specialist and has worked with natural resource managemen t agencies, cooperative research centers, and as a co nsulcanc. He is currently commun ication manager for the Coasta l CRC based in Brisbane. References Alcock D (2004). Pnrtnerships with the Met/in:

Centrnl Queenslnntl Healthy Wnterwnys cnmpnign. Proceed ings Coast ro Coast 2004 . The Second Decade: Coastal Planning and Management in Australia Towards 20 I 4. National Coastal Conference, Hobart, Apri l 2004 Cable T and Knudson D ( I 983) I merpretation as a management tool - the manager's view.

Proceedings of the 1983 National Associat ion of l nrerpreters Workshop. West Lafayette, Indiana. Lockie S. and Jennings S. (2002) Central Queensland Healthy Waterways Survey. Centre for Social Science, Central Queensland University, Coastal C RC T echnical Report.

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EFFECTIVE REGIONALISATION IN COASTAL NATURAL RESOURCE MANAGEMENT J Mackenzie, P Oliver Introduction

Research Design

Coastal natural resource managem ent (NRM) in Australia is currently undergoi ng a process of regionalisacion in accordance with two federal fundi ng schemes: the National Action Plan for Salinity and Water Quality (NAPSWQ) and the Narnral Heritage Trust Extension (NHT2). As part of these schemes, regional collaborative organisatio ns have been established to plan, implement and administer NRM in fifty-six federally idenrified regions. T hrough chis process, rhe Australian Government envisages chat participants from industry, community, government and scientific institutions will all con tribute to the planning and implementation of regional NRM (Whelan and Oliver, 2004). The relationship between each regional body and grassroots NRM groups is critical co chis process, as a significant part of the development and implemen tation of the regional plans relies on the co ntributions of communi ty-based , volu ntary, grassroots NRM groups. T he three-year research project reported on here is in its seco nd year. Using a case srndy approach, we have srndied the collaborative relationships between the newly formed regional body for Sou ch East Queens land (NRMSEQ fnc) and community-based, grassroots NRM groups

Research techn iques in chis qualitative study have included document analysis, field and participant observations, and semi-scrucrnred interviews with key stakeholders. In addition, we have employed a nu mber of participant 'Th in kTanks', where stakeholders from government, conservation , education, scientific, landholder and ocher nongovernment groups are invited to assess the research findings, explore any impli cations and co collaborat ively develop actions arising from the findings. This research technique is o ften referred to as participant evaluation. In contrast to participant observation , participant evaluation seeks to directly involve participants in the research process. As ourlined by Feuerstein (1986) and Garaycochea (1990), chis approach has previously been used to evaluate social and co mmunity development projects. Ir is based upon rhe concept of communal reflectio n and self-evaluation, "i n which chose direcrly involved in the qualitative processes are instrumental in assessing its progress and o u tcomes" (Garaycochea 1990: 82). The inclusion of rhe participant T h ink-Tanks' transforms the suite of data collection techn iques used into an actionresearch and 'citizen science' based research

Research has derived recommendations designed to improve the nature and outcomes of collaboration between regional bodies and grassroots NRM group. (e.g. landcare, coasccare, catch ment management, industry and environmental groups) in two geographic areas of chis region. We have identified some of rhe limits, barriers and bridges to effective collabo ration between these two parties, and have derived recommendatio ns designed to improve the nature and outcomes of chis collaboration. Whilst these findings apply primarily to chis coastal urban/peri-urban case study, there are a number of general implications for narnral reso urce management pol icy and practice.

36 FEBRUARY 2005

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collaboration, dialogue an d knowledge exchange from the point of view of people in community-based grassroots NRM groups and, secondly, focused on the viewpoint of staff and members of the regional body. We have done this: • To provide feedback to participants d irectly involved in the collab orations; and • As a means of accurately informing agency and government policy deliberations of on-ground perspectives of NRM regionalisacion. The discussion below focuses on assumptions that have been observed as barriers to the collaboration and a set of recommendations bu ilding on factors observed to enhance collaboration effectiveness.

Results Assumptions as barriers

Limited space precludes a fu ll discussion of resu Ics. Some key barriers to the development of effective collaborative relationships observed b ut not presented here originate within the relationship between the regional body and the community-based NRM groups, and therefore are ab le co be acted upon by the participants. However, several case srndy participants from community-based NRM groups felt chat significant barriers also derived from assumptions they feel have been mad e by the Australian and State governments when developing inscirncional arrangements fo r NHTII and NAPSWQ. For example, that: • Community-based grassroots NRM groups can endure the hiarns in funding chat has occurred during the regionalisacion process;

project (G reenwood and Levin, 2003: 149; Irwin , 1995: 167) . It also helps to ensure reflexivity and validity in the research process . Without this component, the research techniq ues employed could potentially reinforce the researchers' assumptions and values. "Ir is possible chat researchers will omit a whole range of data in order to confirm their own preestablished beliefs, leaving the method open to charges of bias" (May 1999: 154).

• These grassroots groups have su fficient capacity and incentive to contribute to regional planni ng and the subsequent implementation;

In chis project we have firs cly sought to understand limits, barriers and bridges to

• Regional pr iorities wi ll align with the priorities and capacities of local groups;

• Any in-kind support provided will be adequate for the casks set out in regional plans;


• G rassroots groups identi fy with rhe federally imposed regions in terms of a sense of place; • Industry and business fu nding fo r regional N RM will increase over rime such char regional bodies will beco me largely selffinancing; and • Co ntributions co rhe planning and implementation process will be sufficiently equitable co avoid any potential captu re of the process by specific interests. T hese observations may serve as a basis fo r agency and gove rnment policy deli beration and dialogue between all participants (government and nongovernment) involved in the regionalisacion process. Recommendations - building on good

work These reco mmendations are a summary of 'bridges' chat we observe participants in the case study areas are already bui lding co secure a better outcomes fo r their NRM activities in to the fu tu re. T hey incl ude the need for participants co: 1. Clarify ro les and responsibilities such that both parties understand their own and each other's sphere of influence, capabilities and interests. Much of the frustration of grass-roots group participants we have observed appears linked to rhe, sometimes, unrealistic expectations placed upon regional bodies, their staff and grassroots groups by both gove rn ment and non-government participants. For example, in some instances grassroots NRM groups had envisaged chat with the withd rawal of th eir own paid staff, suppo rt staff of the regional body would co mpensate by undertaki ng a 'catchment co-ordi nator' type of role. Simi larly, there are sometimes unrealistic expectations of the capacity of and incentives fo r the vo lun teers to become involved in rhe regionalisarion process.

2. Identify and create conditions that allow clearly defined participation. T he loss of direct government fu nd ing and of paid staff fo r many grassroots groups has meant chat rhey have a dimin ished capac ity co dedicate their limi ted resou rces co regio nalisarion. In some cases, gro ups have cu rn ed back co their localised scales of interest and attachment. Regional N RM bodies may face a chall enge in addressing chis local focus withi n their broader regional plann ing and impl ementati on wo rk. 3 . Explore the possibilities of collective organisation and empowerment. T o dare, rhe extent to which rhe case study regional NRM body can work with individual grassroots groups appears

limited. T hey have been co nstrained by externally imposed rimelines, rapid change, fund ing uncertainties and complex, existing NRM governance structures. G rassroots groups should therefore identi fy ways char their needs and interests can be clearly co mm unicated co the regional NRM body. 4 . Evolve the role of regional body community support staff to one of extension and linkage. The loss of capacity observed during rhe regionalisarion process fo r many commu nity-based grassroots NRM groups may be partly offset by the regional body identi fying and providi ng staff and facilities co fill specifi c, high priority 'sub-regional needs'. However, ar the sa me rim e, grassroots groups themselves should regularly review and adapt their own focus and mission in light of regional priori ties. S. Devise strategies for the pursuit of mutually beneficial outcomes. Parr of the mandate of regional NRM bodies is co devise strategies and actions char will arrracr non-govern menta l investment. T hey may ach ieve chis by di rectly assisting grassroots groups in framing proj ects char lessen the reliance on govern ment fun ding. 6. Manage regional body governance structures and arrangements adaptively. Regional body governance should be systemati cally reviewed to allow ir to cater effectively for the changi ng needs and motivations of grassroots grou ps, along with ocher parries significantly involved in regional N RM.

In Conclusion Ir has become increasingly popular and some would say disingenuous to descri be relationships between all stakeholders involved in natu ral resource management as 'partnerships' (Cooke and Kothari , 2001 ; Oliver, 2004). However, our analysis of rhe data gained co dare in chis study supports the view chat the relationship between a regional NRM body and co mmun ity-based, grassroots NRM groups should indeed be one of effective partnershi p. As fa r as practicable, chis relationship should be open, participatory and transparent. T his can be achieved through deri ving mu tual goals, articulating a shared intent, recognising each ocher's ski lls, knowledge and limits, developing long-term personal relationships, co mmunicating effectively through dialogue and deliberation, delineati ng roles and responsibilities (with neither parry being made responsible for the aces or decisions of rhe ocher), adopting a co-operative rather than competitive approach, and establishing good conflict resolu tion processes (Oliver,

2004) . Partnershi ps are complex relationships and noc easy to maintain. However, they appear key co effective natural resource management at both local and regional levels.

Disclaimer T he views expressed in chis article are chose of the authors as resea rchers and do not reflect chose of the Q ueensland Department of Nacural Reso urces and Mines or the Queensland Government.

The Authors John Mackenzie (john.mackenzie@griffi rh.edu. au) is a lectu rer at Griffith University's School of Environmental Scudies and is com piecing a PhD on rhe political im pacts of sustainable development on ecological approaches in natural resource manage ment; Dr Peter Oliver (peter. oliver@nrm.q ld .gov.au) is a senior social scientist with rhe Queensland Department of Natural Resources and Mi nes, and is based in Nambour. He recently completed a PhD with rhe Coastal CRC on the developm ent of effective partnerships in natu ral resource management.

References Cooke W and Kothari U (200 I) Participation: The New Tyranny, Zed Books, Londo n. Denzin N and Lincoln Y (2003) The Landscape

of Qualitative Research: Theories and Issues, Sage Publications, London. Feuerstein M-T (1 986) Partners in Evaluation:

Evaluating Development and Community Programmes with Participants, Macmillan , London. Garaycochea I ( 1990) 'The Methodology of Social Development Evaluation," in

Evaluating Social Development Projects, Marsden, D. and Oakley, P. (eds), Oxfam, Oxford . G reenwood D and Levin M (2003) "Reconstructing the Relationshi ps Between U niversities and Society t hrough Action Research" in The landscape of Qualitative Research: Theories and lsmes, Denzi n N . and Lincoln Y. (eds), Sage Publicatio ns, London. Irwin A (I 995) Citizen Science: fl study ofpeople,

expertise, and sustainable development, Roucledge, New York. May T ( 1999) Social Research: Issues, Methods and Process, Open University Press, Buckingham. Marsde n D and Oakley P (2003) Evaluating Social Development Projects, O xfam, Oxford. Oliver P (2004) Developing Effective Partnerships

in Natural Resource Management, Unpublished Ph D T hesis, G riffith Universiry, Nat han. W helan J and Oliver P (2004) "Regional Commun ity-Based Plann ing: T he Challenge of Participatory Environme ntal Governance",

International Sustainable Development Research Conference Proceedings, University of Manchester, UK.

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COASTAL MANAGEMENT TRENDS IN THE ASIA-PACIFIC REGION T Smith, D Thomsen Introduction The first Coastal Zone Asia Pacific con ference (CZAP) was held in Bangko k in 2002 and more than 230 people from 26 co u ntries attended the co nference. Issues of major concern that were raised related to : (i) uses of co astal areas and resources; (ii) roles of the comm unity in integrated coastal management; (iii) education programs for coastal com munities; (iv) h uma n resource development; (v) national and regional frameworks for integrated coastal managemen t; and (vi) data collection and info rmatio n sharing. Co nti nued interest led to the second CZAP co nference, held in Brisbane 5-9 September, 2004, organ ised in the main by the Coastal CRC and CSIRO, which attracted almost 300 participants from 29 cou ntries .

Issues and Priority Actions Ten coastal management themes emerged from the sub mitted abstracts fo r CZAP 04. T he issues raised in relatio n co the themes, as well as priority actio ns fo r coastal management in the AsiaPacific region , h ave been tabulated in T able 1.

U nli ke most con feren ces, CZAP 04 dedicated che fo urth day o f the con fere nce to fa cili tated collaboratio n sessions. A num ber of ini tiatives were agreed to at CZAP 04, such as the establishment of a coastal consulcants netwo rk, che planning o f a book to bridge th e di vide between coastal management and develop ment studies, and potential ways to fo rmalise CZAP as a mechanism to help coordin ate coastal management ini tiatives in the region. A d atabase of cu rrent coastal management in itiatives has also b een established and will be updated for CZAP 06 . W hile CZAP has now had cwo successful fo rums, indicating a high level of sup port fo r CZAP (both from high level government to grass roots com m unity groups), the challenge w ill be to monitor progress o n the p riority actio ns over the com ing years. T he conveners of CZAP 04 are curren cly undertaking an impact survey to determine other plan ned and cu rrent initiatives and to feed these results into che p lann ing o f CZA P 06.

Acknowledgements Major sponsors were cbe C oastal CRC, CSIRO, N ational O ceans Offi ce, D epa rtment of the Environ ment and Heri tage and AusAlD. Special thanks to D on Alcock, Sally Brown and h er team, the local and international organising co mm ittees and the p artici pants.

The Authors Dr Tim Smith is with CSIRO , Sustainable Ecosystems, Brisbane, Tim.Smith@csiro.au, and Dr Dana Thomsen is w ith th e Coastal CRC, Brisbane.

Asia-Pacific countries have agreed on priority actions for coastal management in the region. References These have been selected from che P roceed ings of che Coastal Zone Asia Pacifi c Con fe rence, Brisbane, 5-9 Sep tem ber, 2004. which are avai lable from the Coastal CRC, Brisbane. Bennett, J., Lawrence, P., Johnstone, R., & Shaw, R. Adaptive management and its role in managing Great Barrier Reef Water Quality Dahl-Tacconi, N . Integrating approaches and methods for evaluating management effectiveness of marine protected areas: two Indonesian case studies Capistrano, R.C.G. linking sustainable livelihoods and community-based coastal resource management (CBCRM): the Bolinao experience Mackenzie, R. Sharing knowledge and resources - a networking approach to better management ofAustralia's estuaries. Matthews, E. Traditional management revisited: contemporary challenges of community-based marine resource management in Palau. Newton , G .M . Beyond the abyss! A unique national asset - largely unknown. Udd in Ahmed, A. & Schaerer, C. Sustaining livelihood opportunities for the coastal poor under climate change: a case study .from Bangladesh. Worachanananr S., Career R W, Hackings M, Reopanichkul P & Thamrongnawasawat T. Tourism management in Surin Marine National Park, Thailand. W right A.. The Pacific Islands Regional Ocean Policy - a global first. Wylie R. Awtralia 's South-East Regio11al Marine Plan.

38 FEBRUARY 2005 water


Table 1. Emerging issues and priority actions for coastal management in the Asia-Pacific region. Theme

Emerging issues

Example(,)

Priority actions

Need for sustoinoble coastal livelihoods Disconnects between donor funding priorities ond local issues lock of politico! support

Balance livelihood oppor!unities with environmental needs Undertake social and economic assessment of stakeholder issues and options for action including alternative/additional income opportunities Recognise diversity and utilise 'bottom-up' and participatory approaches Accommodate traditional/customary arrangements Political mobilisation of marginalised communities

Alternative livelihood strategies promoted by the Reducing Vulnerability to Climate Change {RVCC) Proiect !inked to reduced vulnerability of people in Bangladesh by increasing their income end/or food production in climatically sensitive ways (Uddin Ahmed and Scheerer)

Public participation and voluntarism Community leadership Sustainability of community-based projects Indigenous management and planning Environmental education Participatory research and evaluation local knowledge Capacity building

Develop appropriate incentives and rewords for participation and voluntarism Facilitate sustainable governance arrangements at loco!, regional and national scales Provide greater opportunities for local, indigenous and women's involvement Access, value and integrate local knowledge with scientific knowledge Foster two-way learning processes Involve community members from the beginning and throughout participatory research projects Explore ways to document and share community participation tools so that emerging approaches become part of !CM

Philippine environmental organisation (Haribon foundation) worked with coastal community members to improve local resources though resource tenure improvement, capacity building, environmental conservation and management and sustainable livelihood development (Capistrano)

Uncertainty Community participation Integration wi!h planning legol liobilHy Doto quolily and accessibility

Utilise adaptive management principles to ensure continuous improvement in modelling Develop a 'toolkit' for loco! government to assist in the design and assessment of models to ensure that minimum standards are met (eg risk assessment, rigour etc). Creole a meta-database of models, EIS and other assessments Develop and promote skills and knowledge for assessment {eg taxonomy) through tertiary training

Notional support of the marine science and technology base is needed to address large gaps in knowledge, particularly for marine biodiversity and taxonomy in Australia (Newton)

Conduct location specific assessment of no!urol resources Development of appropriate land use p!anning that includes zoning for conservation, industry, recreation/tourism etc in multiple use areas Develop economic incentives and disincentives • Develop effective monitoring mechanisms.

Revision of zoning plan is needed in Surin Marine National Pork, Thailand to ensure effective management {Worochananant et

• Monitoring and assessment • Zoning • Compensation and levies Community porllcipation

al/

Balancing preservation and development Traditional management practices Government and community collaboration Need for policy and legislative support

Develop appropriate communication and conflict resolution mechanisms to ensure transparency and to understand !he interests of all stakeholders Vest authority in customary resource owners

Tradi!iono! approaches lo resource management in Palau provide a base to devise contemporary management structures to cope with current environmental threats (Matthews)

Limi!ed government support Ineffective communication and collaboration Limited access to information

Increase political will and commitment in addition to government and organisational policy (eg scientific advisory forum) Improve linkages between ICM organisations Increase effort !awards cooperative management of shared resources Develop and maintain on accessible regional meta-database

Development of the Pacific Islands Regional Ocean Policy to provide a collaborative framework for ensuring the ocean health in the Pacific Islands {Wright),

Commitment to imp!ementa!ion Integration of policies and planning Integration across scales Community participation Communication

Balance effort between planning, implementation, monitoring and review {planning is easy but commitment to implementation is hard). Manage the source of !he problems (eg. urban development and transition economies) Provide planners with an integration framework. Increase community involvement through 'botlom up' approaches and leadership

Cooperation between the Australian Government (Federal) and relevant State governments improved the planning process and outcomes related to Australia's SouthEast Regional Marine Pion (Wylie)

Consistency and integration Participatory processes Flexibility in design Triple bottom line

Participatory and flexible processes Social learning Sustainability of processes (eg stakeholder support) • from sponsorship lo partnership formal and informal networks • Need for good science and local knowledge Global vs local concerns

• Define objectives in a participatory manner • Utilise both qualitative and quantitative techniques Utilise adaptive processes Undertake capacity building to increase usage and the sharing of knowledge across institutions and countries.

Evaluation of management effectiveness of marine protected areas in Indonesia demonstrated that a combination of tools to design, implement and interpret the evaluation ensured that the information needs of all stakeholders were met {Dahl-Tacconi)

Utilise the adoptive management framework !AMF) to demonstrate integration and how scientific information and tools can support planning and management Develop a learning diagnostic lo improve on-going learning

The AMF can illustrate the comp!emenlorilies of all activities within the Great Barrier Reef Water Quality Protection Plan and could indicate appropriate and ongoing management approaches (Bennett, el a/.)

Develop a training and education directory (to learn from others and avoid duplication) Develop strategic alliances and support community leaders Develop inclusive strategies beyond traditional boundaries

The National Estuaries Network (NEN) coordinated by the Coastal CRC links estuarine managers and scientists around Australia lo shore knowledge and innovative collaborative projects (Mackenzie)

water

FEBRUARY 2005 39


NEW DEVELOPMENTS IN MEMBRANE TREATMENT PROCESSES: PART 2 WASTEWATER REUSE R Tarr Abstract

In 2003 the author was fortunate to be awarded a Fellowship from the Winston Churchill Memorial Trust ofAustralia to undertake a project focusing on recent developments in membrane-based desalination and advanced wastewater treatment. His two papers summarise his reports on his visits to various facilities overseas and coverage of the International Desalination Conference, September 2003. Part I (Water, November 2004) looked at the field of RO based desalination, and associated topics such as developments in RO membranes, pretreatment systems, energy recovery, th e applicability of NF in desalination, and boron removal. Part 2 explores the field of advan ced wastewater reuse using membrane treatment, areas of research for RO membrane development, fou li ng and scaling, a novel cleaning technique, and future projections for the membrane treatment industry.

Advanced Wastewater Treatment Membranes play several important roles in the fi eld of wastewater treatment. The first is as a replacement, or in addition to, clarifiers and media filters, and the second is the use of RO for advanced treatment for reuse. Polishing of secondary or tertiary wastewater can be performed by MF or UF systems, both pressure and submerged (i.e. gravity or suctio n driven), and water suitable for high quality reuse ap plications can be produced by RO treatment of wastewater (WWRO). While the WWRO treatment philosophy is virtually the same as SWRO, the pretreatment process and chemical conditioning must suitably manage the different contaminants and microorganisms in wastewater. H igh levels of organics and bacteria can be effectively controlled by chlorination. The natural ammonia present in wastewater leads to the formation of chloramines, a milder oxidant than free chlorine. Whereas a 2000-3 000 ppm-hr free chlorine exposure

40 FEBRUARY 2005

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Figure 1. West Basin Municipal Water District RO banks (California, USA).

can lead to a doubling of salt passage in PA RO membranes, this same increase will take around 100,000 ppm- hrs using chloram ines.i Within Australia, the prevalence of wastewater reuse schemes is increasing dramatically, and in many ways Australia is at the forefront of developments in this field. Indeed, a pilot sewer mining plant in a Melbourne park was singled out by the IDA President in his opening address to the 20 03 World Congress as being particularly meritorious. This containerised plant draws raw wastewater from a sewer main, screens it, passes it through an aerobic MBR, a UV system, RO and final disinfection with hypo. The water is then disinfected and pumped to the park irrigation system.

p rovide over SML/d, increasing in the future to over 16ML/d, of MF/RO treated wastewater to a range of industrial customers. This has been taken a step further at West Basin Municipal Water District in Californ ia. Wastewater is customised to suit the needs of a range of end users. West Basin's Water Recycling Facility produces five different qualities of recycled water, each undergoing different levels of treatment: • Tertiary Water: tertiary wastewater undergoes an additional coagulation, flocculation , filtration and disinfection stage, for use in industrial and irrigation purposes;

An enormous amount ofR&D is being performed to develop this technology, and generate improvements. Also mentioned was the Luggage Point wastewater reuse plant in Brisbane, an MF/ RO process that sells water to an adjacent oil ;-efinery for use in their steam system and cogeneration plant. A similar facility is currently in the latter stages of construction at Kwinana, south of Perth. This plant will

• Nitrified Water: tertiary wastewater nitrified to remove ammonia, reducing its corrosivity for use in industrial cooling towers; • Softened RO Water: secondary treatment followed by lime softening and M F/RO, injected into wells to fo rm a seawater


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â&#x20AC;˘ U ltra-Pure RO Water: secondary treatment followed by MF then two-stage RO, for use as HP boiler feedwater in an oil refinery. Th is facility is also designed to be a pu blic showcase, with an aesthetically pleasing plane and information cen tre. Educating the community is an equally viral role of this plant.

Figure 2. Singapore's NEWater facility (Bedok, Singapore). A lack of alternative water sources has been a driving force behind che wastewater reuse p rogram in Scoccsdale, Arizona. A joint water and wastewater treatment plant known as che Scoccsdale Water Campus (SWC) recycles wastewater fo r both irrigation and indirect potable reuse.

The Si ngapore NEWater Plane h as taken a similar app roach. An ultra- modern information centre hosts co ntinuous tours six days a week. In formation is a key to selling che con cep t of NEWacer to che people of Singapore. Treated wastewater passes through MF/RO system s, and UV disinfection. The recycled water is used for cooling in commercial buildings, industrial processes such as wafer fabrication planes, and, m ost sign ificancly, fo r augmenting che nation's potable water sup ply.

T he SWC supplies golf courses with tertiary treated wastewater. A portion of chc wastewater is passed th rough an MF/RO process then blended with GAC created Colorado water in a 60:40 combination (37ML/d total). This is then ch loraminaced and pumped co an aquifer below the plane, in one corner of the campus.

Ac present around SML/d of NEWacer is sent co Singapore's raw water surface reservoirs. T his volume is cu rrencly less than 1% of Singapore's daily water consumption, bur w ill increase at a race of 1% per annum to a maximum of 20-25%.

At the op posite co rner, pumps extract water from chis aquifer, and blend it with su rface water co feed the potable water plan t. l e is estimated chat the reclaimed water cakes between hours and days to cover ch is d istance, depending on plane deman d.

T he people o f Sco ttsdale accept chis as an unavoidable reali ty co living in a dese rt environment.

Pretreatment Systems Pare 1 looked at the quali ties o f a pretreatment system, and early indications of a trend from conventional systems coward MF/UF systems. This is especially pronounced in the field of WWRO. Indeed while SWRO planes investigate membrane pretreatment, WWRO plan ts have been implementing it for so me tim e. All the sop hiscicaced WWRO planes discussed above are using MF , as will the new Ground Water Replen ishment Plane being built at che Water Facto ry 2 1 site.

W hile the pretreat ment process is essentially the same as chat of SWRO, the feedwacer quality sup pli ed to the pretreatment system in WWRO can have a large impact on RO performa nce. The benefit of tertiary fil tration over secondary treated effluent prior to a membrane pretreatment system Head Office has been shown ac Californ ia's 3/15 Brisbane Street West Basin faci lity, where the Eltham 3095 performance of a tertia ry fed Ph: 03 9439 2497 tech.sales@amiad.com.au M F/RO system has been superior to a secondary fed system . For che latter, C IP intervals ranged from 2-4 weeks before trans-membrane pressure (TMP) exceeded limi ts. On tertiary feedwacer, CIPs are performed every three months, generally fo r preventative maintenance reasons rather than from TMP. The RO membranes on the seco ndary-MF system undergo C IPs at 6-9 month intervals. I n contrast, the rerciaryM F-RO system has operated since August 1998 without a single CIP, and h as on ly recencly begun co exhi bit rejection issues .ii

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Figure 3. Assorted UF Ho llow Fibre Membra nes (Zenon Environmental , Oakville, Canada). the life of each membrane. In general , the highest possible rejection rares are sought, and each supplier provides representative races for various species. Manufacrurers continue to work cowards improving these rares, in addition to better rejection of boron and other select contam inants, but with races already extremely high, furure improvem ents will be incremental. Energy consumption is the greatest operating cost in NF and RO, so it is important to minimise th e operating pressure. This is limi ted by the need to overcome the osmotic pressure of fe edwacer, and the additional impost caused by fouling and scaling. Membrane man ufacturers typically offer both high rejection elements and low pressure elemen ts. H igh rejection tends to come at higher pressures, and vice versa, so the decision muse b e made as to how to balance these two desirable q uali ties. Low fou ling elements are also available. The low fo uling qualities can be due co acid treatment of the membrane or even biocide impregnation in the brine seal (chat slowly leaches ou t during operation), however their performances have been questioned. Research from the NWRI has found no appreciable d ifference in the fou ling rates of normal and low fou ling membranes. Further, some biocide impregnated brine seals may not be appropriate for potable water applications, and without these the membranes are identical.

Feedwater Chlorination Many RO plants use feedwace r disinfection to co ntrol biological growth. Typically chlorine disinfection is performed at the earliest opportunity in the raw water supply system, with dechlorination immediately prior co the RO system. Once dechlorination occurs, micro-o rganism 'regrowth' comm ences immediately. This shows char many bacteria are disabled, not killed, by ch lorinatio n. Surviving bacteria th rive on nutrients from the ch lori ne-degraded natural organic matter, with the growth rate generally higher than in unchlorinated raw water. le is now generally accepted chat continual chlorination /dech lorination produces inferior results co periodic 'shock' chlorination. Shock chlorination is typ ically performed once or twice per week fo r around one hour, with a chlorine residual of 0 .5-1.0mg/ L. The duration is sufficien t co kill biological growth but insufficient co break down the organics and h umic acid. Such

44 FEBRUARY 2005

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treatment has been found co drastically reduce the frequency of cleaning, and even in the worst of circumstances daily shock chlorination has proven more effective than co ntinuous chlorination/ dechlorination. This is the case for both WWRO and SWRO.

Membrane Fouling and Scaling A large amount of research is being conducted into the fouling and scaling processes, their attachment mechan isms and chemistry, and preventative techniques. Excitingly, the next generation of membranes and processes may co ntain features that greatly reduce, or even eliminate, these problems. Some of rhe more noteworthy fields of research include the following: • Better fo uling-colerance quali ties in membranes; • Chlorine-tolerant RO membranes; • The use of mechanical agitation to 'shake off fo uling accumulations; • Membrane backwashing (currently spiral wound membranes cannot tolerate backpressure, hence backwashing cannot be used); • Scale-prevention magn ets and rods; • Sonic and laser beam pulsations; • Nanotechnology - manipulating and rearranging membrane surface mo lecules co achieve better fo uli ng resistance and longer li fe; • Smart membranes - sensor imbedded membranes co detect fo uling and alter membrane parameters and perfor mance.

Smart Membranes The so called 'smarr' membranes may be impregnated wich substances or enzymes chat initiate particular signatures when certain biological or organic substances, or ionic or chemical species, are detected. The signals could then be detected as an early warning sign of potencial fo uling. Instrumentation sensing the presence of such signatures wo uld aid in this detection. Since scaling and foulin g are slow, cumulative processes, such early detection properties would be invaluable.

Chlorine Tolerant RO Membranes The holy grail of RO treatment is the oxidant tolerant low-pressure membrane. While cell ulose acetate RO membranes are chlorine toleran t, they operate at extremely high pressures and are now rarely used due co uneconomical operating costs. PA RO have grown co become che industry standard, however their drawback is that they are quickly and irreversibly damaged by oxidants such as chlorine. While all RO membrane manufacturers express no positive news regarding the imminent development of a chlorine toleran t RO membrane, news has trickled out from che USBR WaTER Group regarding such a product. While still at an early stage of development, ir follows on the back of promising, but rhus fa r unsuccessful, work from another USB R fund ed collaborative group. Such a breakthrough would be a major advancement in RO techn ology. T he ability to provide continuous disin fection throughout the entire treatment process would significantly cut back on O&M costs, and prevent premature membrane deterioration.

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Gas Based Membrane Cleaning All cleaning techniques and agents currently use water for dilution and delivery of the agents. T his uses up valuable water and generates contaminated waste that requires disposal. A new gas based cleaning technique is currently under development;;;_ In this process, the cleaning agenr/s are drawn through a nozzle by an air stream, generating a two-phase mixture with a high air-co-liquid ratio (with the droplets having a diameter of 25-400 microns) . This is delivered into the membrane feed channels at velocities in the range of 9-12111/s.


The future is This system has been rested on up to two elements in series. Indications are rhar vapour based cleanings can restore membrane performance from 50% of design flu x to over 80% in under 10 minutes. And since no carry water is used, the volume of waste produced is only arou nd 5% of the cleaning waste of a conventional CIP process. Further, it is proj ected that membrane li fe can be doubled when all cleans are perfor med using the twophase techn ique. T h e effectiveness and efficiency of the two-phase cleaning process is the result of the air-to-liquid ratio, flow turbulence and pulsations, surface tension, viscosity and pH. Demonstration of the commercial viability in full scale inscallacions, its performance on up to seven elements in series, and the ease with which existing facil ities could be retrofitted, have yet to be proven. Emerging Contaminants

Em erging contaminants are defined as "a micro-organism or chemical chat was not anticipated as a possib le water contam inant." The NWRI in Orange County, California, operate an ongoing program researchi ng the transport, transformation and fate of new or previously unknown wastewater contaminants such as hormones and other commo n pharm aceuticals, and Nnirrosodimethyl amine (NOMA), and th e rej ection of such contaminants by commercial RO and ocher membranes. A probable human carcinogen, NO MA can be formed when wastewater is treated with monochloramine.iv W ith the increase in membrane wastewater treatment, a greater understanding is requi red of the ability of membran es to remove emerging contam inants from the water. T he need fo r such research has recen tly been highlighted in the UK, where trace levels of the anti-d epressant Prozac have been detected in the drinking water. Wh ile highly d il uted and not co nsidered a health th reat, it does highlight the mechanism whereby undes irable substa nces can enter, and potentially accumul ate, in the water supply. A Roadmap to the Future

In the recently publ ished Desalination and Water Purification Roadmapv it was stated ch ar a belief char the US can ' meet futur e (25+ years ou r) demand for safe, sustainable, and affordable water relying on conventional water treatment planes, is an insufficient answer to the nation's evolving water supply challenges.' T his Roadmap identi fies areas of research and developmen t chat may best lead to technological advances with the potential to solve th eir challenges. 1t iden tifies key issues to overcome that Australia will also face in the near future. Som e key water supply challenges identified include increasing water demand due to population growth, temporary or permanent loss o f water sources due to impairment or prolonged droughts, more stringent health-based regulatio ns, and competing demands from cities, agricultu re, recreation, and the enviro nment. This is an accurate description of Australia's challenges also. The Roadmap identifies three primary needs for the US: providing safe water, ensuring adequate supplies and sustainabi lity, and keeping water affordable. In order to achieve these, numerous near-term (2008) and mid/ long-term (2010/202 0) critical objectives have bee n identified. Near-term targets are chose that can be achieved through technology evolution, whereas the mid/lo ng-term targets require revolutionary developments to be achieved. Some of the key objectives are: â&#x20AC;˘ Reduce capital coses by 20% (near-term) and 80% (mid/longterm) ;

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water

Conclusions The membrane market is relatively young, and advances are occurring rapid ly . Between the vast range of manufacturers, research centres, water agencies and contractors world-wide, an enormous amount ofR&D is bei ng performed to develop this technology, and help generate improvements char hopefully m eet, or exceed, the targets in the Roadmap. Ach ieving su ch targets will transform the way water treatment is perfo rmed. Many applications that can currencly be performed more economically using conventio nal treatment will be challenged by the mem brane market. Conventional approaches may become uneconom ical, inapprop riate or sim p ly inadequate. As a nation, it is vital that we remain at the forefront of new develo pments in rhe membrane ind ustry, ro ensu re rhar we are poised ro rake fu ll advantage of rhe benefirs offered by this tech nology.

Acknowledgements T his project wo uld not have been possible without the generous support of rhe Winston Churchill M emorial Trust, who fu lly funded rhe p roject. T he Trust encourages fellowsh ip applicatio ns from any member of society, and has looked favourab ly on water-related projects since its form ation. I strongly enco urage any mem ber with a worthwhi le project to consider applying fo r a Ch urchill Fellowship. Derai ls can be ob tained from www.churchilltrusr.com.au, or by contacting the author.

The Author Richard Tarr is the director of Rich ard T arr Consulting, Torquay, Victoria. Email richardtarr@datafast.net.au Bibliography i. Andes, K., Bartels, C.R., long, J., Wilf, M., "D esign Considerat ions For Wastewater Treatment By Reverse O smosis", IDA World C ongress on Desalination and Warer Reuse, Bahamas, 2003 . ii. Alexander, K., Guendert, D.M., Pankratz, T.M. , "Comparing MF/RO Performance O n Secondary And Tertiary Effluents In Reclamation/ Reuse Applications", IDA World Congress on D esalination and Water R euse, Bahamas, 2003. iii. Novaflux Tech nologies, Inc., "Evaluation of Cleaning Spiral Wound Membrane Elements W ith The T wo-Phase Flow Process", D esalination and Water Purification Research and Developmen t Program Report #I 01, 2003. iv. N ational Water Research Institute, "Briefings", Volume I 1, Number 2, Summer 2002 . v. U.S. Bureau of Reclamation & Sandia Laboratories, " Desalination And Water Purification Technology Roadmap - A Repo rt of t he Executive C ommittee", Desalination and Water Purifi cation Research and Development Program Report #95, 2003.


THE 1.7 ML/D DALBY GROUNDWATER DESALINATION PROJECT T Fagg have worked but the design process followed specific steps co ensure char rhe supply objectives were achieved. The second stream involved purring together the items char although nor abso lutely necessary fo r che plant ro operate, experience and research had shown would improve the operation, mai ntenan ce and performance of the plant.

Abstract This paper outlines the design, the layout, and the performance of the Dalby Desalination Plant, which provides 1.7 ML/d of potable water (approximately one third of the townsh ip's consumption) from brackish bores.

Introduction T he Dalby Water Supply services rhe

The RO Design

I 0,000 people in the Town of Dalby

and a small number of customers in rhe ad join ing Wambo Shire. The town's demand peaked in rhe early 1990s at about 2500M l/a bur for many reaso ns chis has red uced gradually to under 2000Ml/a over th e last few years. Traditionally over 90% of chat demand was met by the high quality shallow alluvium borefield with rhe remainder supplied from Loudou n Weir and fu lly treated. Howeve r th e shallow bores have decl ined at a rare of abo ut I 0% per year for many yea rs with a number of rhe bores now at the poi nt of abandonment with little hope of recharge. Alth o ugh the sto rage at Loudoun Weir was increased to 588MI chis storage is less than 50% reliable at char demand. Tr was obvious char if nothing was done rhe rown co uld be without water.

get what we want and accept the challenges that such a plant bri ngs This means the plant must be efficient, rel iab le, easi ly maintained, easi ly operated and should also max imise the resource by a high recovery." T o dare, the Dalby plant has met or exceeded all the performance ex pectations and has so far at least, met the challenges stared above. T his has nor been by accident,

A full history of the trials, specification and costings of an RO project for a small inland town. Desalination allows the use of water chat would be otherwise unavailable fo r town supply. Deeper all uvium can supply water chat is raced as only fai r irrigation quality but at 2000 TDS it is far coo salty for potable supplies. Whilst the deep alluvium is no t an unlimited resource rhe aquifer is much larger in ex tent and capacity than the shallow high quality all uvium , and che cu1Tent borefield is anticipated to last fo r over fo rty years.

Design Issues "Long after the plan t is constructed and the con tractors and consultan ts are gone, Dalby Water will have to operate, maintain, live with and pay for a desalination plant. Therefore, we have to

however, and the good performance has been achieved by thorough research and careful design. In considering rhe design of che plane, there were two main screams of thought. The first stream is purely rhe technical RO design. There were num erous options, layouts and equipment cho ices char would

Like all treatment plan t projects, the design process scarred with the: • the broad quali ty derails of che bo res proposed fo r supply to the plant; • the quantity and quality of the water required fro m the plant; and • where che plant is to be located. Raw water quali ty is the single factor char most influences any desalination plane design and the chemi cal and co nsci cuencs considered are much more di verse than the mere salinity because there is the potential to exceed the sacurarion co ncentration of so me compounds at high recovery. Table l summarises the borefield available. Table 2 summarises rhe raw water qual ity of the three bores. W hilst che salinity of the water is rhe best indi cator of the pressure requirements of the RO process, the characteristics chat were of particular concern in chis proj ect were: • silt density index (SDI); • barium sulphate; • silica; • iron. All RO manu faccu rers reco mmend a maximum SDI of 5 bur generally levels below 3 are preferred if long term operation

Table 1. The borelield Bore ID

No. 10 bore No. 11 bore No. 12 bore

Output

Depth

Conductivity'

Location

7-29 Fixed 2.9 7-30

55 metres 25 metres 55 metres

3,300 1,200 3,300

500 m east at plant at plant

• microsiemens/cm

waters

FEBRUARY 2005 49


with minimal fouli ng from particulate matter is to be expected. There was considerable variation in rhe SDI results (31O) bur experience has shown that rhe SDI's improved with continuous running of rhe bore. The aim was to ach ieve a recovery of 7580% bur if so in the reject stream barium sulphate and silica would exceed the saturation concentrations by 580% and I 0% respectively and membrane fou ling co uld be expected. Additionally, at least one of the bores contained amounts of iro n which would also be expected to cause fouling.

Pilot Trials A pilot plant designed to simulate rhe effects on the most critical parrs of the plant was obtained and operated for over 6 months. T he pilot plant included multimedia filtration, 5- and 1- micron cartridge filters and rwo membranes in a two-stage arrangement wirh recirculation. T he operating experience gained from the pi lot plan r demonstrated char: I. 80% recovery did not cause undu e problems with chemical scaling; 2. anticipated dose rates of an tiscalant were adequate and no further chemical pretreatment such as acidification was required; 3. rhe water contained no biological or oth er unanticipated fouling agents; 4. rhe prefil trarion train i.e., multimedia and rwo cartridge fi lters gave sufficient pretreatment to protect rhe membranes from colloidal or iron fouling whilst sti ll giving adequate fil ter runs; 5. mul timedia filters would probably need backwashing every few days, but the cartridge fi lters would only require replacement approxi mately every 4 weeks; and 6. the low pressure brackish water membranes would supply the necessary fi nished water quality.

Plant Specification Given the success of the pilot process, it seemed logical to adopt this process flow sheet as the standard for the full scale plant. A derailed design repo rt was prepared that reflected this and included derail on the performance of the pilot plant. Ocher process options were still available but at rhis stage it was considered li kely rhar the process most likely to be successful was a two stage reverse osmosis process with multimedia filtration and at least one train of micron level cartridge filt ration, with a system recovery of approximately 80%, yieldi ng ca. 1730 kL/d of permeate.

50 FEBRUARY 2005 water

The general arrangement of equipment on the RO skid. As mentioned previously, the design ar this stage was also influenced by the need to include both the tangible and intangible elements that research and expertise from the United States has shown to be good practice. This included the need to cater by design for:

• energy efficiency - high efficiency motors and pumps well matched to the loads and duties and fitted wirh VFD; • lowest possible chemical consumption the use of degassing and blend ing to reduce the need fo r chem ical pH correction; • low noise;

Table 2. Characteristics of the supply bores (concentrations in mg/L). Item

Bore 10

Bore 11

pH Conductivity Total hardness Total alkalinity Reactive silica Total silica Fe Total Mn total Ca Mg Na K SO4 Cl NO3 PO4

7.4 3340 421

7.7

8.1

1200 73.9

3370 447 357 30 27 0.09

757 0.1 0.33

0.6 37.5 114 0.1 0 .59

HCO3 CO3 OH TDS CO2 Colour Ba Sr TOC

446 l

544 l

0.1 18 10 20. l

0 .1 721 17.8 7 0.1 0.3

NH3

Typical bore water quality 20th April, 2003

386 36 32 0.02 0.01 70.3 59.6 552 2.4 11 7

2 0.1 2.2 0.9 0.1 0.05

446 26.5 29 0.06 0.01 12 .5 10.2 251

0.9 0.1 0 .05

Bore 12

0.01 90.3 53.9 550 3.2 113 833 0.1 0 .33 435 l 0.1 1890 5.7 7 0.1 1.8 0.1 0.1 0.05


• the separation of chemicals, water and electri ci ty as far as possible; • effi cient membrane clea ning equipment e.g. a heated CIP system with variable fl ow rate, fi ltration and direction control; • logi cal and safe layout of equipment; • provision of access fo r maintenance; • use of pumps, valves, process equipm ent and electro nics compatible with ex isting systems and locally available; • computerised moni to ring and control systems utilising C irect and local integration partners; • integration with existing water rrearmenr plant system; • process eq uipment conservati vely loaded multiple uni ts such as filters to allow some redundancy during backwashing ere.; and • process equipment appropriate fo r cask appropriate constructio n material s. These key requirements were inco rpora ted into a relatively co ncise section of a perfo rmance-based specification. A performance-based rath er than prescriptive style of specification was deliberately chosen to allow designers and contracto rs to innovate and/o r use the latest techn ology adva ntageously where possible, whilst still meeting the co nceptual requirements li sted above. A few abso lute items were included , those considered mandatory. T his tendering approach provided both positives and negatives fo r th e project, these being: Negatives: • Mos t contractors offered packaged plants that failed many of the key requ irements of the project. • Sign ificantly more detail was requi red from the contractors to allow assessment of the offer. • Tender assess ment was technically more difficu lt than sim ple conformance/nonco nfo rmance. • Co n tractors who offered designs that met the water quality requirements but not the other less tangible factors did not seem to understand why their design was not selected. • So me des igns offered were grossly inadequate. Positives:

• By having to assess the design, the tender assessment tea m was able to determine which contractors had a good understanding of the project requirements. • Contractors were able to use their skills and experience to enhance the design of the plane. • Ir reduced rhe amount of derail necessary in rhe tender documentation.

Pre-treatment consists of multimedia filters, 5 micron and

The Contract Wendouree Water T reatment (WWT) was ultim ately awa rded the co ntract due to the following: a. a competiti vely priced offe r; b. acceptance, understanding and agreement on the des ign phi losophy c. a des ign approach that in volved working with Cou ncil to deliver a project which was what Council wanted as against what the co ntracto r would or co uld supply. WWT being a local supp lier also offered a number of advantages. T he detai led design was largely undertaken by WWT and adopted the fo llowing steps: l. co ncept des ign for tendering - \VWT 2. detailed design for approval - WWT with Dalby T own Co un cil and Parsons Brinckerhoff input; 3. derailed design for co nstruction - WWT with Dalby Town Council and Parsons Brinckerhoff in put; 4. fac tory construction and mock up Wendouree Water T reatment with Dalby T own Cou ncil; 5. plant installation and construction Dalby Town Coun ci l monitoring; 6. PLC integration using Dalby T own Council'S preferred subcontractors - Dalby T own Council with WWT input; 7. commiss ioning - WWT with Dalby T own Council monitoring and operati on. Key modifications to rhe con cept design included a co ntrollable blending facility to blend so me of the raw water with the · permeate, thereby giving the operator a chemical free method of controlling the pH, alkalinity etc of the treated water. A number of minor modifications and design decisions were made during the design, construction , installation and commissioning stages.

l

micron cartridge filters.

In reality the contractor, wi th co ntinuous collaboration with the client and the consultant, was given substantial design freedom, within the specific prescripted requirements of the spec ifi cati on and the broad co nceptual elements that Dalby T own Cou ncil had determ ined as necessary to make a good plan t.

Plant Details Bore Water Supply

T he plant is suppli ed by three bores (see Table I). T he preferred method of bore utilisation is to operate all th e bores together in order to spread the demand across the aqu ifer and limit rhe draw down and flow in rhe areas immediately adj acent to the bores. T his should provide long term benefits to th e bores and aqui fe rs. Both large bores, however, have sufficient capacity to supply rhe plant on their own if necessary and th e plant has been configured to allow this. Normally all rhe bores supply the plant via a pressure regulated manifold , with bore 11 on a fi xed output, bore IO on an operator adj ustable fi xed flo w and bore 12 operating on a Pl D loop to maintain the necessary pressure and to make up the flow deficiency. Bore l O is controlled by a dedicated radio telemetry link with rhe PLC, with bores 11 and 12 wired directly to rhe RO plant PLC.

Filtration All water entering th e plant passes through the multimedia filters. Although three units are normally onli ne, th ese are conse rvatively sized so that two units can handle the full flow if necessary. Though rhe filter backwashi ng can be automatically initiated based on ti me they are currently only manually backwashed on

water

FEBRUARY 2005 51


an ap proximate 30 day cycle and have not yet experienced significant differential pressures between backwashes. Although chis may indicate chat the multimedia filters are almost unnecessary, the following factors should be considered:-

of the raw water changes, it is necessary to size the pump over a range of duty points. It is also likely to expect chat under most circumstances the pump will be operating at less than its rated maximum. Use of a Variable frequency d rive (VFD) and selection of a pump with good efficien cy over a wide speed range is necessary to ensure chat energy costs are minimised. Whilst VFDs may be perceived as more complex than a simple throttling valve, the energy sav111gs are enormous .

• the bores are as yet being operated in a manner chat reduces the likelihood of moving very fine sand and colloidal matter around in the aquifer; and • the operation of the bores well below maximum capacity reduces turbulence and aeration in the bore holes and the likelihood of oxidation of iron occurring. Some fin e colloidal material and sands are regularly detected in the backwash water. The media fil ters also provide some security against major changes in bore water quality and issues such as maintenance that may occur in the field and impact on water quality. Regular testing of the water after the media filters has indicated an SDI of virtually zero. WWT included the novel approach of using plant reject water for backwashing the fi lters, thereby maximising the overall recovery achieved by the plant and causing very little d isruption to the overall process. The five-micron bags and one-micron cartridge filters provide the last line of d efence fo r the m embranes with regard ro particulate and colloidal fouling. These are also conservatively designed to allow operation with one of che four trains offline for cleaning and maintenance. Standard 40 inch x 2.5 inch one-micron cartridges are utilised in multiples to achieve che maximum specified flow rates of 12-15 litres/minute per 200mm of cartridge length. At the specified loading, a minimum of two months between change out was expected, but given the lower than expected level of particulate and colloidal loads, the cartridges are expected to achieve a six month life without exceeding an accep table level of d ifferential pressure. The cartridge filters are there to protect the membranes so the sizing and selection must be correct.

The array of 1 micron cartridge filters and the main high pressure pump. important to ensure long membrane life and minimise fou ling. Antiscalanr typically costs approximately $11 per kg so efficient use is a prerequisite of least cost operation. Antiscalant is dosed ahead of the cartridge filter trains so that complete mixing is achieved and the filters provide protection against any antiscalant quality control issues.

The RO Train A Grundfos CRN 90-2 of 15kW provides prefilrrarion pressure boosting to l 20kpa - 330 kpa to overcome fil tration pressure losses and can be controlled via a PID controller based on post filrrarion operating pressures if necessary. A Grundfos CRN 90-4 of 30kW provides the pressure for the operation of the first-stage reverse osmosis process and boosts pressure from approximately 260kpa to 710kpa. This pump is the single largest user of energy in the plant. Because of the need to vary the duty point as the membranes foul and if/when co nductivity

Antisealant Amiscalants can be common acids such as HCl or H 2SO4 which work by altering the pH of the feed stream sufficiently to impact on solubil ity threshol ds, however they are usually more complex substances which work in a variety of ways. The pilot plant trials indicated char the proprietary substances Flocon 135 and Flocon 260 were both su itable at dose rates of around 5mg/l, however rhe main plane has operated on Flocon 135 thus far. Anciscalanc selection is relatively sire specific and the correct selection is

52 FEBRUARY 2005 water

Salty discharge is released into 21 hectare desalination ponds located 2kms east of the desalination treatment plant.

A PID control fun ction is available for ch is pump bur as predicted during commissioning chis was found to be unnecessary due to rhe very stable operating conditions. Speed adjustments are now performed manually by the operator as required however, such occasions are infrequent and are only necessary when operating conditions change eg. membrane fou ling or changes in conductivity. T he high pressure pump is typically operating at 85% of fu ll speed . The RO skid is configured for two-stage single pass operation in an 8+4 arrangem ent with each stage achieving a nominal 50% recovery. Rej ect from the first stage goes onto the second stage so chat overall a recovery of at least 75% is achieved. Each vessel houses seven Dow Filmtec XLE-440 8 inch m embranes, the specifications of which are detailed below: • surface area - 40.9m:'S/element • pressure - 6.9 bar • flow rate - 48. lm~/ day • salt rejection - 99% • per element recovery - 15%. The use of seven elements per vessel allows maximum recovery to be achieved per stage without exceeding the per element recovery limits. TDS from the combined ourput is approximately 120mg/l o r about 220 micosiemens/cm conductivity. All sampling and resting points are centralised to the one location and all remote pressure transducers are backed up with local gauges. Due to the increase in concentration of the feed to the seco nd stage (reject from stage one) a pressure increase is necessary between the stages to maximise second stage recovery. In this plant, a Grundfos CRN45-3-2 of l l .9kW provides the 4 70kpa increase in pressure for the second stage. Due to the relatively stable relationsh ip between rhe first stage reject pressure and rhe feed pressure requirement for the second stage, a fixed speed pump was chosen for interstage boosting. Reject from the RO skid is transferred by residual pressure to the low-set 200kl


concentrate storage rank or is pumped directly ro the evaporation pond com plex by a Grund fos CR45-4-4 of 5.5kW operating on a PIO controller based on rank levels. T he concentrate transfer pump ru ns at relatively low speed to minimise friction head losses bu r is also sized for a fu ture plant duplication. A graph of the pressure profile th rough the plant is shown in Figure I .

Post Treatment Permeate fro m rhe RO skid is transferred by resid ual pressure to the permeate storage rank of approximately 45kl. Sufficient perm eate is stored ro provide make-up water for membrane cleaning purposes. In addition , permeate is aerated via a 4.5kW submerged turbine self-aspirating aerator ro scrip residual CO 2 out of so lu tion and thereby raise rhe pH. During pilot plant operatio n, lab trials determined that approxi mately 15 min utes deten tion rime substantially improved the pH. Al though abo ut 30 minutes detention rime is available, the tu rbine aerator does not deli ve r a suffic ient volu me of air and only increases the pH from approximately 5. 8 co 6.2/6.3 in service, which although less than anticipated has nonetheless proved to be adeq uate. Trials were also conducted with the process of alkalinity recovery whereby the pH is adjusted chemically prior to air st ripping, thereby resolublising some of the CO 2 in the form of carbonate and bicarbonate alkalinity and improving the srab ili ry of the water. Whilst rhis is theore tically possible, it was unable to be replicated in rhe laboratory, so all chem ical pH adjustments are currently performed after CO 2 stripping. A 25% caustic soda solution is dosed ar a race o f ap proxi mately 36 litres per day which increases the pH by a further 2 to 3 points to around 6.5. Water comi ng from RO processes will very often be corrosive with negative LSI values, a pH below 7 and little or no alkalinity. The original design as proposed by rhe co ntractor intended to meet the contractual requirement of achieving water with a near neutral LSI and pH in the range sui rable for potable water (ideally between 7 and 8) with rhe use of soda ash to adjusr the pH and add alkalinity afte r aeration. Whilst rhis was a suitable option, labo ratory trials with permeate from the pilot plant demonstrated chat an adequate and stable produce could be produced by blending raw bore water with the aerated permeare at a ratio of approximately I part raw to 4 parts permeate. Th is warer would then only require minor pH adjustment under so me

Plant Pressure Profile

1000

800

a. "' -"'

600

400 200

oL-- - - - - - - - - - - - - - - - - - - - - - - - ~ Bore Manfold

Prefiltration boost

Post filtration

t-lgh pressure pun,,

Interstage boost

Concentrate stage 1

Concentrate

stage 2

Process Stage -

Pressure kPa

Figure 1. Pla nt p ressu re p rofile. scenarios and is usually blended with ocher sources (if ocher so urces are being used) as they enter the clearwater storage at the water plane. Dalby Town Counci l and WWT jointly worked on a modification of the design to incorporate an operator-adjustable controlled race blending fac ility to allow blending of the permeate with raw bore water. This allowed the deletio n of the soda ash dos ing facili ty which would have substantially impacted on operating costs. Blending also increases the yield to about 80% at only a relatively small increase in operating cost. All costs presented in this pape r refer to the unblended product and not to the total delivered. T he broad qualiry derai ls of the blended and unblended permeate are shown in Table 3.

Operation of the Plant The plant to dace has been relatively straight-forward to operate with an average operation and maintenance requirement of approximately 3 hours per day. T yp ical operational casks include: • reading of meters and recording throughputs etc; • water quality analysis; • checking co nsumption of anrisca lanrs and caustic soda; • inspectio n of the plant; • review of operating pressures etc; • permeate flush of rhe RO skid (currently on a once per 72 hou rs programme);

• inspectio n of co ncentrate line to evaporation pond compl ex; and • dai ly mon itoring of the evaporation ponds. Apart from a few mi nor water leaks and some faulty welds on the ca rtridge fil ter housings, rhere have been no major prob lems experienced on a day to day basis. T he Treatment Plant O perators have rece ived ongo ing trainin g on the operation and maintenance of rhe plan t and given the relatively trouble free operatio n, have been able to adeq uate ly resolve mosr minor iss ues. W hilst the O perators perform most of the day to day mo ni rori ng, the Techni cal Sup ervisor perfo rms the long term mo nitoring of the process and tech nical support fo r more co mplex issues. T he relatively close prox imi ty of the co ntractor, WWT and Council's integrators, Downey Engineeri ng, has also been very advantageous and the value of chis cannot be dimi nished.

Operating Costs Table 4 summarises the operating and depreciation coses. The total cap ital cost was abo ut $2.8 M of which 40% was provided by Scace government subsidy. T he costs do nor include bore pumping or delivery from rhe Water Treatment Plane. By compariso n, operating coses fo r treatment of surface water under the same rerms are typically 28-37c /kL (without

Table 3. Water quality.

Raw Water Permeate Blended Permeate

Conductivity us/ cm

pH

Alkalinity

Hardness

2800 200 710

7.4 5.8 7.3

380 8 80

420 4 64

water

FEBRUARY 2005 53


depreciation but allowing for some known mai ntenance costs) depending on water quality and demand cond itions. There has been no allowance made for major maintenance of equipment as chis is co nsidered to be funded by depreciation on an ongoing basis. In reali ty the plane would be maintained, replaced and renewed as required rather than reach ing design li fe and being 100% replaced at that rime. le should be noted chat operating costs are very sire specific and such coses as shown above relate ro rhe Dalby situation only and not ro the desalination process in general. Even sites char have similar water quality may have significancly different operating coses because of different operating regimes, labour availability, power coses etc.

Membrane life:

Concentrate Disposal

Caustic soda 36 L/d ot $ 175/tonne

The disposal of concentrate from any desalination plane is normally a difficult and coscly pare of any project. Overseas experience is that approximately 50% of the total capi tal cost may relate ro concentrate disposal and the experience in Dalby rends ro confirm this. Such coses may not necessarily be in infrastructure, but may include studies, environmental assessments, monitoring, management plans etc. Even where planes are located next to saltwater eg. the ocean, concentrate disposal should not be considered as just throwing a pipe out and leering ir go. Fo r Dalby release to the river system was not possible. Irrigation with blended supply was possible but none of the farmers approached were interested. Discharge to the Dalby Wastewater Treatment Plane was also possible but would have a negative impact on the plane's BNR process and rhe receiving waters. lr was accepted chat deep well injection was rhe best sustainable option for Dalby in the very long term if a su itable aqu ifer could be found, but this was is unknown and un likely. Evaporation ponds were therefore deemed the on ly viable option, but wou ld require substantial enviro nmental management. Whilst the Dalby climate offers qu ite reasonable evaporation races, there were many environmental issues to be considered, including: • rhe locarion of rhe plant and the likely location of rhe ponds - anywhere wirhin 10 kilometres of the planr cou ld broadly be classed as flood plain; • planr and ponds locared in good quality farm ing lands, much of ir high value irrigation cotton land; and • in rhe vicinity of existing water su pply sources, both underground and surface. Given rhe enviro nmental issues, frequent consulrations rook place with rhe

54 FEBRUARY 2005

water

Table 4. Operating costs based on 1728 kl of unblended output/day. Power kW:

Prefiltrotion, 9.5: high pressure 19: interstage 9.5: concentrate transfer 1.2: Aerator 3.7 Sundry, estimated 4: Total 47 kW. Demond tariff 18 $/kW/month, consumption 6.5 c/kWhr Filtration:

Cartridges change, 90 days interval (already exceeded) ot $500 per time 84 membranes ot $3,100 per membrane. Design life 5 years. Chemicals for CIP:

90 doy interval (already exceeded). Chemicals $500 per clean ing event Antiscalant:

6 kg/doy ot $11 /kg Labour:

Ops 2 hr/doy. Routine Mice 1 hr/doy ot $35/hr Post treatment:

Plant 'life' 20 years, but not oil items will require replacement Plant replacement cost : $1,000,000 Long-term utilisation estimate 85%

Cost breakdown, cents/kl Energy Cartridges Membranes Antiscolont CIP chemicals Caustic Labour Concentrate disposal Subtotal Depreciation

5.8 0.3 9.7 3.5 0.3 0.4 6.1 3.4 29.6 9.3

Environ mental Protection Agency (EPA). Approval of a Site Based Management Plan was fina lly granted, including daily, weekly, monthly, yearly and five yearly monitoring including grou ndwater. Auditing and contingency plans were formulated and meeting and traini ng sessions were held with neigh bours, staff and regulators to provide a forum for com muni cation and informatio n transfer. Usefu l feedback was provided by neighbours and was incorporated into the Plan. A reasonable estimate of the cost per kL of product is about l 0% of the total.

Conclusion The Dalby Plant has been successfully operated for over six months and has made a substantial contribution to the Town 's water supply at an operating cost as good or berrer than the few available alternatives. The project has followed a course from concept to reality that is perhaps unconventional in local government, and has had to break some new ground to do so. A plane such as th is bri ngs wirh ir many operation al, maintenan ce, finan cial and

environmental issues that must be adequately addressed by Council and ultimately the co mmunity if the long term community expectations are to be achieved.

The Author Terry Fagg is Techni cal Supervisor Water & Sewerage, for th e Dalby Town Council, rerry_fagg@dalby.qld. gov.au

Acknowledgements Particular thanks to Ian Cameron, Water Executive, Parsons Bri nckerhoff, Brisbane, who has worked hand in glove with the author, from the initial survey of source options, the proposal to Council to utilise desali nation, through the design and conscrucrion of the plant, in a manner far beyond, and more productive, than the usual consultant-client relationship. Ian Cameron icamero n@pb.com.au And to Bob Ward, Managing Director and Principal Process Engineer of Wendouree Water Treatment, whose skill combined with his ready collaboration has ensured the success of th e project. wendoure@bigpond.com.au


JUNCTION SEALING A UNIQUE PROBLEM R Petterson, A Sutton Abstract

systems. T he resul cs of rhe monitorin g programs identified chat as the main sewe r lines were im proved rhrough rehabilicarion fo r serviceabilicy and strength , complete seali ng was nor achieved due to ocher weak points such as co nnections to maintenance holes and more commonly, private branch connections. Having lined che sewer main wirh a srrucrural lining wi th a des ign li fe in excess of 50 years, research and developm ent focus shifted to branch co nnections with the aim to provide a similar lo ng term solution.

Large and small warer aurhori cies alike are now specify ing the installation of Jun crion Sealing Ficrings (T Seals) as pare of their sewer pipe lin ing co nrracrs. Specifications fo r chis wo rk req ui re the lin ing material used in the T-Sea l co have a minim um service life of 50 years. Australian sewe r reticulation pipework (incl uding the house service co nnections) have a combination of site co ndirions and con fig urations chat is uni que in th e wo rld . In Figure l. Typ ical grout packers as provided by American Austra lia rhe main sewer Logiball. Ma inli ne and lateral packers of this type have been used extensively by a nu mber of Australian companies. rericu lari on pipes are Junction Reinstatement predominancl y 150mm in A History d iamerer, with 100 mm or remotely reinstated junctions, were 150 mm branches enrering the main at Fro m the beginni ng of trenchless pi peline undertaken over 20 yea rs ago . In chose early various angles. High ambient wo rking rehabilitation in Australia in the 80s it was days ir was co nsidered revo lurionary chat a temperatures and roor infes carions in rh e the availability of incern al robotic cutters, as sewer could be rel in ed and a hole cue in the branch line are commonplace an d jun ctions pri mitive as th ey were then, chat gave true liner ar rhe juncrion location all wichour sea ls are requi red to as a mi nimum, extend mea ni ng to rhe term NO DIG pipel in e excavatio n. in to and pasr the first joint in the branch. rehabili carion. As rime wenc by expectations in creased Kemb la Wacercech Pry Limited (Kembla) Mose of rhe early lini ng work unde rta ken and lining rechnology expanded to march ini tiated and has continued wirh a research was based on st ructural rehab ili tation and these new requirements:- longer lengths and development program fo r rhe so it was considered benefit enough to be (30 0-400111 in one in scall acion),larger Australian developed T iger T system which able to cue open the branch connection diamerers (1000m m and beyond) and structu rally repairs and seals branch d iffe renr shapes (ovifo rm , elliprical) all from inside the lined pipe. As time co nnections. Recen cly, the company has became a matter of routine. As co nfidence progressed, infiltration prevention became also added a un ique new development with in lining technology grew, attention turned more of a conce rn and so sealing of the the introduction of purpose buil t co nnection cue out was required. T he industry had been using chemical As the Australian trenchless technology industry has grout sealing fo r infil tration co ncrol in discovered, systems and equipment developed overseas cracked and open jointed mainline pipes. T his technology was adapted in the 90's fo r simply do not work in our smaller pipe sizes or under sealing of branch co nnections as well. Systems developed fo r chis application (by our higher ambient temperature conditions. America n Logiball) were in troduced to Australia and were co nsidered to be an to che ocher critical aspect of pipel ine eq uipm ent to enable any roots up the adequate so lution fo r rhe sealing of rh e rehabili tation; the remote reconnection and branch pipe to be removed from withi n the jun ction (Figure 1). rehabili tation of rhe branch co nn ections. main pipe. Thus, rhe branch pipe ca n now Unfo rtunately, there is no evidence chat Maj or cities and towns in Austral ia have be clea ned and a T-Seal installed wirhou c grou r seals lase longer chan 10 years when millions of private and commercial premises rhe need to access the private propercy. T his used above the wa ter cable. As a result, che connected to sewer reticulation systems. As paper exp lains rhe unique solutions to these expectations of cl ients increased and che crenchless technologies became more widely unique problems. industry was asked to develop quality adopted as a maintenance and rehabilicacio n solution, authorities utilising these scrucrn ral seal at che branch with a design Introduction revo lutionary methods undertook life of 50 years to march rhe mainline In Australia, the firsr truly No Dig performance monitoring of rhe employed lining. pipeline rehabilicacion projecrs, includ ing

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asset management So What is the Unique Problem? The requirements for the sealing of the junction vary between water auth orities. The main reason for rhe variance between water authorities is the difference in rhe way the sewer assets are owned. For example, it is more likely char water au rhori ties in rhe southern parts of the east cost of Australia are responsible fo r the sewer pipe connectio n up to rhe property bound ary where as in the northern areas of the east coast, water authorities are more likely to be responsible for the sewer up to the first pipe joint in a branch co nnection from the main sewer.

CRACKED PIPE

In addi tion ro rhe differences Figure 2. Typical HSL Lining set up. in asset ownership, the vast majority of the main sewer reticulation pipes are 15 0mm T here are a number of H SL Lining diameter with branch co nnections either systems in Australia that are able to line the 100mm or 150 mm in diameter entering at private sewer from the Inspection Open ing varying angles to the mainline pipe. Root (l/O) located inside the property boundary infestation is also often found in the ro the main sewer. The major advantage of co nnection and must be removed prior ro chis type of repair is char the en tire length of sealing. As our trenchless technology rhe ho use con nection branch is structurally ind ustry has d iscovered o n so many repaired and sealed against water and root previous occas ions, systems and equipment ingress. T hese branch linings can be developed overseas simply do not work in installed separately or in conjunction with our sm aller pipe sizes or under our higher the lining of the m ain line sewer, however, ambient temperature co nditions. HSL linings d o nor provide any additional As a result of the u nique problems caused structu ral support ro rhe connection point by the basic differences between Water itself and customer dis turbance often occurs authorities requirements and the particular because access is required to the ho use sewer configurations of our region, the long holders property for each process required term structural solution for rehabilitating fo r rhe installatio n of rhe HSL lining (i.e. connections has had to be developed or refined cleaning, pre-CCTV, lining and post specifically to suit Australian conditions. lining) .

Sealing to the Property Boundary House Service Line Lining Considerable time and money has been spent by the major pipeline rehabili tation companies in Australia in d eveloping H ouse Service Line (H SL) lin ing system s ro suit the u nique configuratio ns experienced in Australia, which are among the m ost di fficult to li ne in the world. T he optimum so lution fo r Australia is a small bore (1 0 0mm and 150 mm) structural Cast In Place Pipe (CIPP) system char can be completely installed from only one access point. Ir must negotiate boundary traps and vertical bends and use installation eq uipment char is easily transported and able ro be set up in areas of difficult access such as the rear of private properties . C IPP linings are well known to the industry and are accepted as providing a long term structural insrallarion. (Figure 2)

56 FEBRUARY 2005

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These co nnection li nes are gen erall y 1. 5 ro 6 meters long and as they use similar materials ro rhe m uch shorter T -Seals, they are a considerably more expensive

Figure 3. Top Hat T-Seal.

option and rake longer to install. A critical aspect char m u st b e cons idered when app lying chis option is char each lin e sealed requires access to the resident's prope rty. T h e works are typically und ertaken from I/Os with in the property wh ich in many cases are buried or simply non-existent. Locating rhe I/O, raising the l/O, undertaking the clean and survey of the line, performing any repairs to broken pi pes prio r to linin g and finally installation o f th e lini ng mean that multiple visi ts are often necessary. Even with custo mer co nsent it is difficult to gu arantee access as and when requ ired . Experien ce gained on large p rogra ms on wh ich over 1,000 house se rvice li nes h ave been rehab ilitated hig hlighted the logistics involved in und ertaking such a program and showed char these s up port activities can require th e m ost attenti on . Ir would b e generally fair to say chat the logist ics required to undertake a HSL lining program are as involved as any m ain sewer lini ng program.

Sealing to the First Joint - Top Hat So called 'Top Har' systems can provide a lon g term structural solution and have been available fo r a number of years. In Australia, this technique involves a shore rube of feltlike material with a rim attached to one end i.e. a 'top hat' with the lid removed . The felt composition is impregnated with a resin and then laced around a bladder which is p ulled into positio n using a winch cable placed down the branch p ipe. Once in position the bladder is inAared by air press ure and th e cable kept in tension so as to ho ld the top hat firring in position u ntil the resin hardens. (F igure 3). Top H at systems perform with varying degrees of success d epending primarily on the degree of bond achieved between the 'rim ' section of rhe 'top hat' and the pip e wall or pipe lining. T he system described above has been used in Australia bur is nor suited to rhe smaller reticulation sewer diameters and is generally used only in larger d iameters. As the number of connections in sewers of 375mm and above is relatively small the ' top hat' system may remain as a practical option fo r the larger size range. Consideration must also be given to the requ irement to access the I/O for the installation of this system which as outlined previously, can add considerable work to a seali ng program.


asset management Sealing to the First Joint - T-Seals T he development of the T-Seal system is the ultimate solution ro rhe unique set of design and installation pa ramete rs mentioned above. The T-Seal systems are based on a specially fab ricated T shaped parch made from a fibrous rype material which is impregnated with a ambient cure resin. The impregnated T patch is placed over a purpose built packer, transported in ro rhe sewer and positioned at rhe location of rhe co nnection using a small CCT V camera. The packer is rhen inflated which pushes rhe T-Seal out and into rhe branch connection. Ir is held in this positi on until the resin has hardened (F igure 4) . T he hardened patch nor on ly seals rhe con nection and rhe firs t joint but also provides structural support ro rhe entire co nnection area. T his is particularly beneficial when the connection is cracked or where rhe branch pipe has been 'broken' into rh e mainline. As with al l sealing systems, rhe junction must be cleaned to ensure a good bo nd is achieved between che T-Seal, the host junction and mainline liner. A major advantage of che T -Seals is that insrallarion does nor require access to rhe resident's property at any rime.

Photo 1. Picture of root mass in junction .

Photo 3. Picture of Kembla' s Tiger T from main line .

DLti'PIIJDWM!WIIWJJWIII It'

Photo 2. View of lined pipe and junction after being cleaned from inside the Main Sewer line using purpose built equipment.

Photo 4. Tiger T, looking up the junctio n.

Cleaning the Junction

mass marcer from che junction at a nu mber Specifically, the higher expectations of different angles. Kembla and other associated with the sealing of rhe junction Cleaning rhe junction was and still is a industry leaders again invested rime, know created a unique problem rhar called for req uirement of all junction sealing systems how and money ro develop systems unique innovative and unique solutions to be which, using conventional methods, ro Australia to address this problem. Figure developed by rhe companies operating in requires the use of che 1/0 and therefo re 6 shows the cleaned junction. Figures 7 and the industry. access to rhe residents property and 8 show Kembla's T iger T' . associated issues. It was obvious rhar rhe T hese solutions not only addressed the benefits of the T-Seal system would nor be design requirement of a quality seal desired Conclusion fully real ised un ti l cleaning of rhe junction ar the junction wirh a design life of 50 With the maturing of the Australian co uld be undertaken from rhe main sewer yea rs, bur also led to imp rovements in the Trenchless Technology ind ustry, line. execution of sewer rehabili tation programs, specifica tions and increased custome r T he main purpose for the cleaning of rhe the majo r improvement being that the requirements have lead ro significan t junction was to ensure that it was free of cleaning and sealing of junctions can now improvements in rehabilitation methods. roots and other substances such as be undertaken co mpletely from far, grease and fore ign objects that within the main sewer, which may interfere with rhe bond significantly reduces rhe direct between the T-Seal and rhe host impact on the house holder. Sewer pipe. Co nventional methods fo r lines and connections can now clean ing the main lin e, such as root commonly be completely Excess resin fills gaps curring, are only one di rectional and and cracks rehab ilitated without disruption to are not capab le of clea ning up into services or rhe requirement to gain any junctions. As can be seen in Previously insta lled access ro the house holder's Figure 5 the root curcer wi ll remove lining property. only the part of a root mass rhac is present in rhe main line, leaving the The Authors rema inder and majority still firm ly lodged in rhe junction . Richard Petterson is General Manager and Alan Sutton is The solution must be able to address all circumstances ac the Engineering Manager of Kembla junction which requi red the Warercech. PO Box 170, Bellfield development of a system that was NSW 2191. Ph: (02) 8732 2222, able to deliver high pressure water Figure 4. Configuration of a T-Sea l installed inside a email: capabl e of cleaning significant root square (90°) branch. kembla@kemblawaterrech. com.au

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MANAGEMENT OF RISK IN PIPELINE ASSETS S Burn • Shutoff Valve Insertion - identifies whether shut-off valve insertion should be preferred instead of pipe replacement. The mi nimum length of pipe resulting from che valve insertion is also specified. If the length of the pipe is too short fo r a sh utoff valve, replacement is considered instead. • Budget - limits the total availabl e annual fun ds to be expended in any one year. T his amount (less the cost of repairs, rebates, social costs and penalties) is then used to co ntrol which pipes are considered fo r replacement. • Pressure Reductio n - if a maximum operating pressure is specified, pressure reduction val ves are inserted in the appropriate pressure zo ne, to ensure that no pipe in the netwo rk exceeds that pressure. This will reduce the probabili ty of pipe fai lure. • Discount Factor - specifies the discount rate to be appl ied co all futu re cash flows in determining the Net Present Values of the coses of repair, replacement, rebates, social costs and penalties of the pipe network over rhe assessment period. • Sensitivity Analysis - allows for up to two parameters to be set in conducting a sensitivity analysis over a specified range.

Summary

Pipeline Asset and Risk Management System (PARMS) is a suite of computer-based models for management of water supply network assets. PARMS is offered exclusively by CS IRO . T he fi rst two of the threepart suite are now available fo r implementation. PARMS-PLANNING allows assessment of operational strategies for both short and long-term repair and replacement of water pipelines. The Typical failure in a reticulation main. software can assess replacement needs based upon the pred icted number of to manage pi peli ne replacement analysis. failu res in any one year, and is easi ly The user can identify hot-spo ts or clusters tailored to meet customer needs. and focus investigations on scenarios fo r PARMS-P RIO RITY assists water renewals, pressure reduction and valve authori ties to make day to day decisions on insertions. renewals and replacements in water A variety of pol icy optio ns are available reticulation pipes to maintain service levels fo r users to explore and assess the impact withi n regulatory limits. that such policy changes would have on the Managing Water Reticulation Pipe overall performance of their water supply Failures network assets. T he policy options available are: The cost of pipeline fai lures is a considerable expense for water aurhorities. • Replacement T rigger - Incidents chat will The issue of reducing future fai lure prompt the replacement of an asset. frequencies and the ensuing failure • Failure - determines rhe maximum consequences has been the focus of many annual nu mber of failu res to be allowed in investigations. Initially failure predictions a pi pe segment befo re action is taken to allowed users to allocate resources to pipes either replace the pipe (o r to introduce an with high predicted failure rates. Recent addi tional shut-off valve) . attentio n has been on developing Decision Support Systems, such as PARMSPARMS-PLANNING and PARMS-PRIORITY software PLANNING and PARM S-P RIORITY. packages are linked to an organisation's existing asset This has been possible because of rhe vasr improvement in the quality of data information database and incorporate failure curves collected by some water authorities, which has opened up co nsiderable opportunities derived from past failure information. for improving pi pel ine renewal decisions. • Interruptions - determines the maximum Appropriate data is now commonly Scenario Analysis annual number of unplanned in terruptions available in many organisations responsible Analysis of the resulting scenario to be allowed in a pipe segment before for the maintenance fo r pipe networks. simulations provides a range of graphical action is taken to either replace the pipe However such organisations often and tab ular results to be displayed, (or co introduce an additional shut-off experience difficulties in analysi ng and includ ing: valve) .. using this data for management of their • Detailed overview of current network pipe networks. T he efforr of these time • Nee Present Value - provides an option co nfiguration including breakdowns by co nsuming casks is mi nim ised by PARMSto replace a pipe when the Nee Present material, age, size and failures. PRIORITY by leveraging the new Value of the discounted predicted • Cost breakdowns over the scenario improved data qual ity to overcome hurdles maintenance and associated coses over a period. thus providing water authori ties with specific period exceed the discounted cost to replace the pipe and any (usually minor) powerful and easy to use tools fo r data • Pipeline fai lu re rates and numbers by exploration, fi ltering and reporting in order ma intenance coses of a new pipe. material type.

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asset management • Customer interruption races and numbers by material types. • Change in network lengths and , numbers by material types. T he overall approach of PARMSPLANNING is co forecast the expected annual number of failures fo r each individual type and size of pipe asset for che next 30 years, based on the age of each asset, its inscallarion and operating cond itions and its failure history. For each individ ual pipe segment or asset, che expected failure rares are estimated for each year in the forecast period. The prod uct of the fa ilure race and the Network Display in PARMS-PRIORITY. length of the asse t determine the number of failures in chat asset. The rebates, penalties and custo mer preferences, coral number of failures in the system in any as well as flooding and damages. one-year is the aggregate of the failures in Coses and failu re races and probabi lities each asset. T he in ventory of the actual asset are combined to associate risk values with network enables the ful l netwo rk different scenarios, relating co pipeline performance co be ob tained from relati vely renewal , pressure reduction and va lve simple models of performance based on only insertions. Scenarios are ranked on various a few parameters. risk and financial indicators such as neeT he costs of maintenance are provided present va lue of savings/losses, and payback per repair and the cost of replacement assets period. are calculated from coses per un it length. Replacements reduce the length of existi ng PAR.MS-PRIORITY provides che user assets and crea te a new asset in the year of with a range of data exploration featu res, replacement. whi ch aid understanding of ex isting data, as The numbers of assets which have well as supporting reporti ng. multipl e failures in any one year an d thus Easy database querying means chat the are targeted fo r replacement (depending user can focus on important aspects of thei r upon the customer preference) are es timated networks with just a few mouse cli cks. The using a modi fied Negative Binomial database queryi ng is also linked co reports, distribution, or physical/probabilistic charts and visual network displays. models, wh ich provides the probabili ry of Any selection from a database query can multiple failures in a year for a known be analysed using the Failure Prediction expected failure race. too ls. The enti re selection or individual Risk Analysis and Prioritisation pipes ca n be analysed co give predicted failure races; as well as probabi lities of The PARMS-PRIOIUTY analysis is based on estimating risk measures wh ich require failures for ind ividual pipes or shut-off bocl1 a method for esti mating failure blocks. The failure pred ictions are also probability as well as a method fo r linked with coses co provide risk measures. predicting coses and conseq uences of failures. T he failure forecas ting is developed from a water authority's failure database using rigorous sracistical analysis. The predictions model provides failure races and probabilities for each pipe in the network raking into consideration the age of the pipe, material type and diameter, operating pressure, length of pipe, the pipe's failure history and where possible soi l. The coses and consequences of failures are related co repairs, customer supply interruptions Distribution of assets by pipe type, pipe age.

The user can rank pipes, material types, renewal clusters, suburbs and much more, on che basis of predicted performance or historical performance according to a range of indicators, such as net-present value of predicted failures and historical failure races. PARMS- PRIORJTY supporcs che user in identifying renewal clusters, the effects of pressure reduction and valve insertions. The risk calcu lation engine ca n be used co investigate userspecified scenarios, and to prioritise between differen t actions.

..... •••••••a:.i = .....

----

The use of PARMS-PRIOIUTY by orga nisations responsible for managemen t of water reciculacion pipe networks will improve che efficiency of decisions as well as using the daca co better understand the pipe network. Decisions are improved in terms of: • red uctio n in future failure frequencies, and the associated failure costs an d consequences; • improved ability co maintain custo mer service levels; • lower coses for renewal; • achieving acceptable environmental and social impacts.

Implementation· Working with You PARJ'v1S-PLANNING and PARMSPRI O RITY are linked co an organ isation's existing asset in formation database and incorporate failure curves derived from past failure in formation. Physical model s developed by CSIRO are also incorporated in che algorithms. CS IRO provides water authorities with: • Initial analysis of water asset management needs • Ta iloring of PARJ\'1S-PLANN1NG and PARMS-PRIORITY to sui t individual needs

i:

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~.-.-

• Use of historical fai lure in fo rmation and development of physical failure models • Customised costing schedules • Ongoing support

The Author Dr Stewart Burn is leader of the Urban Water Infrastructure Group in the CSIRO Di v. of Manufacturi ng and Infrastructure T echnology, Highett Vic 3 190, Email scewarc.burn@csiro.au, Ph: 61 3 9252 6032, Fax: 61 3 9252 6244.

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MODELLING A FLOOD DETENTION BASIN

MERGER TO STRENGTHEN POSITION IN DOSING PUMPS Consolidating its in ternational position in che market for dosing pumps, the Danish pump company, G rundfos, has recently acqu ired rhe ALLDOS Group . Grundfos has an annual turnover of over 1.5 b ill ion Euro and 12,500 employees. T h e com pany has production companies in 12 count ries and sales organisations in 40 countries worldwide. le del ivers pumps for a range o f purposes, including the construction sector, industry, water supply, metering and wastewater treatment as well as the manufacturi ng of motors and electronic items. In the area of dosing pumps Gru ndfos and ALLDOS produce motor-driven pumps, primarily for the metering of various chemicals and flui ds in water treatm ent. G rundfos has been invo lved in chis business for just fo ur years. ALLDOS will become the Centre of Excellence for all chemical-dosing business and technology. ALLDOS group managem en t remains unchanged wi th Ewald P Diesslin CEO, together with his deputy and CFO, D an iel R Brandlin , retaining their positions. G rundfos' Director fo r the dosing d ivision, Jes Munk Hansen, will become a member of the ALLDOS Group management. The ALLDOS subsidiary in Oceania, ALLDOS Oceania, will also remain unchanged, and Managing D irector, Ossie Salo nen, has welcomed the merger as a "decisive strengthening of our market position in all areas of chemical metering and water treatment technology."

Contact ALLDOS Oceania Pty Ltd on (07) 3712 6888, Email: info@alldos.com.au, www. al/dos.com

DRAWING ON INTERNATIONAL EXPERTISE A WS designs, builds and operates water and wastewater treatment plants across Australia and N ew Zealand and has earned a reputation as an industry leader when it comes to working in public private partnersh ips. AWS is part of Degremont, che water specialist business within Suez.

Water Business aims to keep readers alert to business news and new product releases with in the w ater sector. M edia releases s hou ld be emailed to Bri an Rault, b rault@h alledit.com.au, or Te l (0 3) 9530 8900. AWS can leverage Degremont's worldwide experience in b rackish or sea water desalination. W ith more than fifty years experience and 250 developments in the construction and operation of largescale reverse-osmosis and nanofil rracion treatment units, Degremont is a worldwide leader in d esalination . It can design , construct, operate and maintain complete treatment planes equipped with reverseosmosis or nanofiltracion uni rs, alo ng wirh the appropriate pre-treatment and posetreatment steps . AW S relies on proprietary technologies developed by Degremont to provide reuse of urban and industrial wastewater solutio ns. C lients can benefit fro m AWS 's experience in providing wastewater reuse plants for various applications including agricultural and landscape irrigation, aq uifer recharge, and industrial and urban reuse. A WS can also support long-term operation and maintenance partnerships by provid in g a full and long- term guarantee on process performance and asset condition. Ongoing benefits p rovided by rhe operational phase include: • optimised process perfo rmance including predictive process modelling; • long-term asset management based on maintenance and capital replacement programs; • accred ited quality, safety and environmental management systems; • access co international operat ions expertise.

Forfurther information contact (02) 9224 7900 or email aws@aws.aust.com, www. austra!ianwaterservices. com. au

T he Margaret Street d etention basin for combined sewage and scormwarer provid es storm-flooding protection w ithin urban Launceston, Australi a. T he partly covered and partly open basin provides first -flush capture, containment and discharge of co mbined sewage overfl ow to rhe council's wastewater treatment plant. The structure was completed in 2004. The model that had been used co plan the structure has been convened into an Info Works CS hydraulic model co allow testing and refi nement of the control rules required fo r optimal operatio n of the basin. Launceston C ity Council's d rainage system collects both stormwater and sewage discharges in the sam e pipes. Increased dem and s on rhe system resulted in flo oding of the central business district and low-lying residential areas. The Margaret Street Detention Basin, a sophisticated overflow facility located in a public park , is part of rhe strategy proposed by GHD to address the p roblem . In 2002 a comprehensive hydraulic m odelling study of the Margaret Street catchment was undertaken by Earth T ech E ngineeri ng co calibrate the proposed detention-basin site and assess its performance for selected rainfall events.

Building the network model To build the model, raw ESRI SHP fi les were imported in to the Info Works CS modelling package, and the network model was cal ibrated using fifteen months of data collected at the proposed sire of the basin. Separate calibration exe rcises were undertaken for wee and dry weather flows. The d etention basin allows dry-weather fl ows to pass through the basin and into the low-level gravity pipel ine. In wee weather both sewerage and scormwarer fl ows are scored in a covered-flow control fac ility with the 'cleaner' water from extreme rain fall even cs being d ecai ned in an aboveground storage basin. T he flows out of the tan ks and the above-ground basin are co ntrolled by two large gates. T he fi rst flush is scored for subsequent discharge and treatment.

REVOLUTIONISE YOUR STORMWATER MANAGEMENT WITH CIVILSTORM™ MODELLING SOFTWARE FROM BENTLEY'S HAESTAD METHODS PRODUCT LINE CivilStorm is the only commercially available software package that lets you analyse all your storm sewers, inlets, channels, culverts, detention ponds, and reservoirs in one package. For more information about this software, see the inside front cover of the February issue of Water Journa l, visit our website at www.haestad.com/tryit and enter code 7880, or e-mail us at sales.haestad@bentley.com. 60 FEBRUARY 2005

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