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Volume 30 No 3 May 2003 Journal of the Australian Water Association

Editorial Board F R Bish op, C hairman 13 N Anderson, W J Dulfcr, G Finke, G Finlayson, G A H older, 13 Labza, M Muntisov, I' Nadebaum, J I) Parker, F Roddick, G R yan, S Gray

•, IVnrer is a refereed journal. This symbol indicates chat a paper has been refereed.

CONTENTS

Submissions I nstrnctions for authors can be found on page 3 of this journal. Submissions accepted at: www .awa .asn .au/ pu bl icati 011s/

Managing Editor Peter Stirling

News and Supervising Editor Brian McRae AW A Technical Director Tel: (02) 9413 1288 Fax: (02) 9413 I 047 Email: bmcrae@awa.asn.au

OPINION 2 2 3 4 S

My Three Key Areas Aquaphemera Water in Flux My Point of View, Western Auslralian Water Strategy Healthy River Ecosyslems: Vision or Reality?

Technical Editor

ASSOCIATION ACTIVITIES

E A (Bob) Swinton 4 Pleasant View Cres, Wheelers Hill Vic 3150 Tel/ Fax (03) 9560 -1752 Email: bswinton@bigpond.net.au

10 Including AIWA Report

PROFESSIONAL DEVELOPMENT

Water Production

13 Details of courses, classes and other upcoming water events

Hallma rk E ditions PO 13ox 8-1, Hampton, Vic 3188 Level I, 99 13ay Street, 13righcon, Vic 3186 Tel (03) 9530 8900 Fax (03) 9530 89 1 l Email: halhnark@halledic.com.au Graphic desig n: Mitzi Mann

Water Advertising Natio n a l Sales M anager: Brian Rault Tel (03) 9530 8900 Fax (03) 9530 8911 Mobile 0411 354 050 Email: brault@halledit.corn.au

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

Australian Water Association PO Box 388, Artannon, NSW 1570 Tel +61 2 9413 1288 Fax: (02) 9413 10-17 Email: info@awa.asn.au A '\VI A ABN 78 096 035 773 J-ltt. W J-ltt.

Federal President Rod Lehmann

Executive Director

AUSTRALIAN WATER

C h r is D avis ASSOCIATION Australian Water Association (A WA) assumes no responsibility for opinions or statements of facts expressed by comribucors or advertisers. Editorials do not necessarily represent official A WA policy. Advertisements are included as an information service to readers and arc reviewed before publication co ensure relevance to the water environment and objectives of AWA. All material in W11ter is copyright and should not be reproduced wholly or in part without the written permission of the Managing Editor.

Subscriptions

NEWS BYTES 16 Featuring selected highlights from the AWA email News

CROSSCURRENT 20 Waranga Basin Pumps, M Ba Les 23 Australian Water Charity · A Progress Reporl, C 24 Obituary: Dr John Patterson, J Keary

Davis

INTERNATIONAL REPORT 25 Worst Western Drought in 108 Years,

A Hudson and S McKenzie

CONFERENCE REPORT 27 3rd World Water Forum • A Global Extravaganza, c Davis

SPECIAL FEATURE: The 20th Biennial Convention, Perth 29 Highlights 31 Awards 37 Keynote Speakers Report by EA (Bob ) Swinton

WATER 38

·, LEAKAGE REDUCTION BY ADVANCED PRESSURE CONTROL: KHAYELITSHA

Atwo-month payback achieved (2003 Michael Flynn Award Winner) R McKenzie, H Mostert, W Wegel in

44

·, ADVANCED REUSE · FROM WINDHOEK TO SINGAPORE AND BEYOND

Ahistory and an extrapolation I B Law

Water is sent to all AWA members eight rimes a year. le is also available via subscription.

Visit the Austral an Wat r HOME PAGE Assoc ation and access news, calendars, bookshop and over 100 pages of Information at

OUR COVER: The Ozwnter Co1111e11tio11 n11d Exhibition brought together 11enrly 2000 peopleforforrr days of 11et111orki11g, tnlki11g n11d e,y·oyi11g the nt111osphere ni Perth's B11rswood Co1111e11tio11 Ceutre. WATER MAY 2003

1


FROM

THE

PRESIDENT

MY THREE KEY AREAS As I write th is, my fi rst colu m n as Preside nt, we've j ust wrapped up Ozwate r in Perth. The whole event see med to me to have gone well and I was very pleased to see the evide nt sense of owne rsh ip and enth usiasm that members hold for our Association. I am hono ured to have an opportunity to serve as President and the next tw o years are going to be exciting ones for m e. Barry N o rman set a great example as Preside nt and h is cla imed w eakness in tec hnology areas was, of course, a strength in that his conside rable managem ent ski lls were appli ed to smartening up our operations generally. ! ' 111 gratefu l to Bany fo r his contribution and I ho pe we can build o n what h e ac hieved . In m y term , I ho pe to address th ree key areas: b uilding 111e111be rshi p ; re in fo rcing N atio nal Special Inte rest Croups (N SIC s) ; and o ur national profile. At the risk of making a rod for m y ow n back, here are some targets that I ho pe to achieve by th e tim e I leave o ffi ce: Membership T hanks to th e efforts of M ic hael Se ller, our m e m bership sa les manager, co rpo rate m e mb e rship in A WA has b losso m e d recently, w ith the total now being over 700. T hat's an amazing achi evement and I am sure Mi chael w ill keep chalking up more runs on the board. Individual me 111bersh ips, though, are not as buoyant - we 'churn ' so m eth ing lik e 12% of me mbe rs eac h yea r and o ur rec ruitm ent on ly just 111atc hes that attritio n - so th e re's a n eed to improve o ur recruitm ent marked ly. W e ha ve very good penetratio n in consulting fir111s and key w ater industry contractors, but th e major w ater authorities, govern m en t age n cies and local authoriti es are all poorly represented. As people in those organisations play a vital role in water aff:1irs, I fee l this is an area w e m ust do 111uch better. I plan to ginger up o ur Branches and ou r staff, o ne of the best recruitm e nt methods is 111e m bers getting 111embers - if you know someone who works in water but doesn't belong - suggest joining A WA. It's now easy to do o n che web site and , as all me mbe rs know, it's excellent valu e. NSIGs

N ominally, w e have arou nd 20 Natio nal Special Interest Crou ps, but the fact is a few are acti ve an d the rest do n't do muc h . T he bottom li ne is cha t a gro up w ith an ac tive and comm itted champion usually goes fro m strength to strength, w h ile one lacking such an indi vi dual usuall y languishes. W c have so me gro ups th at rely large ly 0 11 staff mem bers to keep th em afloat, bu t ou r staff 2

WATER MAY 2003

Aquaphemera

Rod Lehmann

resou rces are too lim ite d to offer that so rt o f support w ide ly and on an ongoing basis. Th e key he re is fo r those m embers w ith a passion fo r a parti c ular wa ter n iche to put the ir hands up and to volun teer to dri ve a Cro up , eith er nationally or at Branch level. All it takes is a call to 1300 361 426, or an e-ma il to info@a wa.asn .au - o ur staff w ill show you the ropes. O f course, not eve1y on e wa nts to be a con ve nor, but if you keep us informed on your preferred in terest group areas, we w ill be in to uch w ith yo ur needs and can direct resources appropriate ly. AWA's Profile I am constantly frustrated that media people consult th e m ost a111azing array of people and organisations abo ut w ate r issues, bu t al m ost n ever A W A. As an o ld technocrat, I am alive to the fact that AW A's approac h to wate r matte rs may have been a bit ' m iddle o f the road ' and techn ical, b ut I fee l we now have a mu ch broader ra nge of inte rests and ha ve much to offe r. My ambi tio n fo r m y term is to ra ise the ba r, so that media people have AW A top-o f- mi nd and we are invited to comment w hen a w atery subj ect cro ps up . This can o nl y happe n by a mu lti-faceted thrust to be as relevant, topical, in formed , interesting and available as possible. I am goin g to ensure that adequate staff resources are available to ach ieve th is, but acti ve engagem ent of me mbe rs, personall y and th rough their branch es, w ill also he lp to raise awaren ess of AW A natio nall y. Conclusion Having marked the territory, I hope I can deliver over the co ming years and I hope too th at mem bers will suppo rt these goals. I am also keen to know w hat me mbers fee.I about A W A and w ha t am bitio ns yo u have for the Associatio n . If yo u 'd like to drop a lin e at any time, please use o ur posta l address o r email prcside nt@awa.asn.a u.

R od Le/1111a1111

Th e rec e n t bu s hfi res t h ro u ghou t So u th E as t e rn Australia were a stark reminder of the fra gil e co- existence w e have w ith nature . In Canbe rra , the ho rren do us fi re storm , w hich claimed 4 lives and ove r 500 homes, brought ou t the best in the community and su pporters from across Aust ralia. Unfortu nate ly a few individuals used the occasion for their own pol itical o r special interest pu rposes, ca using angu ish to those w ho toiled so valiantly to com bat th e fires and mainta in the areas prior to the fi res. The realiry was, that the conditions were ex tre me. In th e ACT, only o ne ti ver w as still flow in g naturally and that was at 10 M l/day fro m a 150 sq u are ki lo m e t re ca tc hme n t . Rivers w ith catch111 ents up to I ,000 square kilo m e tres had dried up . This had on.ly occ urre d o nce in th e last 100 years of re co rds. A bushfire indi cator mode l developed for AC T catch m ents, using river base flows and previous bu shfires in the reg ion , had indicated that th e catc h m ents w e re in a critical state from mid November. T he m o del correlates the declin ing river flo ws aga inst th e bu shfi re p ote ntial. W hen t he flo w starts dropping dramatically, ic indica tes that no t o nly are the grasses and bushes d ying, but also the trees. T hus by J an uary, when t h e b ush fir es o cc u rre d , th e catchments had been in the critical state for 2 months. To suggest, as it has bee n, that it w as not a rare event or that some specifi c actions coul d have sign ifi cantly redu ced the impac ts, is inge nuous at best. Unfortunately, the proble ms did not end w hen the fi res w ere put o ut. With 95% o f th e AC T's primary water su pply catch me nt bu rn t , th e subse q u e n t ra i ns , w elcome eve ryw he re else, have impacted on the wa ter quality in the dam s. But once again , organisatio ns fro m arou nd Australia are working together to help understand and solve the resultant pro blems.

- R oss K11ee


OZWATER

REPORT

KEYNOTE SPEAKERS AT OZWATER Associate Chief Justice Dennis O'Connor, Ontario In June 2000 he was appointed by the government of Ontario, Canada, co con duct two inquiries into the conta mination of the Walkerton water supply w ith E Coli 01 57: H7 and Ca111pylobacter jej111ii. In a small town of 4500 population , n1osc of the population suffered some illness, some 2300 suffered severe illness, a nd seve n peop le died. (His ph otograph of a funera l service was most dramatic) . T he economic effects have been estimated to total som e $64 mi ll ion, but more significantly has been the erosio n o f confidence in public institutions . His first report (released in J an 2002) was to un cover w hat went wrong A very ro ugh summary is chat it was a train of fa ilures in seq ue nce, a litany of small comp lacencies. The source was cattle manure spread (strictly according to the regu lations of the time) within a few hundred m etres of one of th e shallow well s that supplied the town, fo llowed soo n after by heavy rain. Th e prevalent image was that all gro und water was inherently safe, and sporadic re ports of E Coli in sam pl es performed by a private sector laboratory were virtuall y ignored. To compou nd chis the operators had for many years responded co criticisms by residents of th e taste of th e water by reducing the c hlorine dosage, saying chat beca use they drank it themselves, it must be O K. T he operators them.selves had had no forma l training, being 'grandfathered' into the ir j obs. Governm ent inspectors did not detect these lapses, because of inadequate finance and training. When government standards were tightened, nobody went back to c h eck on existing system s. Th e Province of O n tario is by no 1neans backward, but there was a failure to extend the Best P racti ce used in the cities co the small er commun ities. The broader enquity, w hat co do about it, was assisted by an Advisory panel c hai red by Professor Steve Hrudey. It was a consultative process, not adversarial , and has spawned 25 research papers. The 93 recommendations, (May 2002) ar e widely ava ilable on the web sites and in part, through Hrud ey's student,

Samantha R.izak, have been instrum ental in the drafting the c urrent Australian guidelines of multiple barrie rs. T he most significant are chat ca tchm ent planning processes must give priority to water quality and farmers must abi de by appropriate regulations. Secondly, accreditation of operators is mandatory (see M cKay, Water, February 2003). Th e net cost has been estimated to be som e $7 to $19 per ho usehold per year.

health of an ecosystem must be assessed in terms of its resili ence to vari ability. If this isn't challenging enough, he indicated chat all of his points could be equally applied to our approach co economics; raising multiple issues, including questions about our approac h to water markets. Finally he maintain ed that the Flagship Program will lead to an adaptive society, and it is the current fron ti er of ecological soence .

Professor Graham Harris

Paul Gagliardo

As C hief of the CS[R.O Flagshi p Progra m , he oversees research into the aquatic environment, how to explain the phenom ena we observe, and how we predict the outco mes o f our actions and policies. H e maintained that we tend to mange fo r stabi lity and security, in direct o ppositio n to th e inherently variab le nature of ecologica l systems. Com m on practice was to average out ecological data, and analyse it fo r tre nds, applying an equilibrium mod el. H owever, the m odern app roac h is th at th is is a dangerous si mplifi cation , because th e co mpl exity an d in teraction of bi ological systems, combined with the variation i n weathe r patterns, leads to considerable ' noise' in the data. wh ich is in fact the important part: it is actually variabili ty and correlations that govern these syste ms, wh ic h are shaped by extreme events Th is questions the ability of widely accepted models to predi ct the outcom es of, for example, land use chan ge on receiving wate rs. M odern models must look into 'ra nges' rather than ' averages' and the

Pa ul is a Senior Program Direccor for EarthTech Inc , and was pre viously involved in the Sa n Diego program for water re-use. H e co mmenced on th e st ea d y red uction in rainfall fo r both South ern Cali fo rnia and W estern Australi a, and cyn ically correlated the dry periods over the past 100 years with pol itical decisions to 'do so mething', for example, bu ilding the 1000 km Aquedu ct fr om the Sie rras to Los Angeles. In Ca lifornia, wate r in itself has no valu e, its price rela tes only co transport and treatment costs. H owever, since there will be no more naw ral suppl y, (if not less), the price/ supply equation can not apply. Th is is accentuated by the fact chat agricultural prices are on ly abo ut 1% of urban prices. In a dry year supply shortages in Ca li fo rnia are about 10- 12% of demand. Conseque ntl y a 65 person Advisory Committee has been set up co consider the effects of climate change and agriculcural, urban and en viro nm ental usage trends for each of ten regions in the State . It is not a happy scenario . Therefore alternative sources must be developed .. . ie . water recycling, groundwater, sea water desalination (probably coupled to a base-load power plant) and the sources p referably located closer co the areas of u nsatisfied demand rather than necessitating construction of eve n longer pipelines or aqueducts .. even if there were fr esh water available. The big issues are reliability, not cost, with the pricing stru ctu re designed co encompass standby and sec urity matters. Fi nally, h e sa id caking action in noncrisis times w ill always result in better decisions.

Water Advertising To reach the decision-mal<ers in th e wa t er fi e ld, y ou should cons id er advertising in Water Journal, the official j ournal of Australian W at er A ssoc iati o n . F o r inf o rm a tion a b o ut advertising ra tes, please contact Brian Rault at H allmarl< Editions, Tel (03) 9530 8900 o r em ail brault@halledit.com .au

WATER MAY 2003

37


a

WATER

LEAKAGE REDUCTION BY ADVANCED PRESSURE CONTROL: KHAYELITSHA, SOUTH AFRICA R Mckenzie, H Mostert, W Wegelin Abstract Khayelitsha is o ne of the largest townships in South Africa with a population of approximately 450,000. It is located approximately 20 km from Cape Town on the Cape Flats (a large flat sandy area at or near sea level). There are approximately 43,000 serviced sites with both internal water supply and water borne sewage while a further 27,000 lowcost housing units are supplied from communal standpipes. At the beginning of 2000 the water supplied was almost 22 million 1113 /a. The Minimum Night Flow (MNF) was measured to be in excess of 1,600 111 3/hr so the level of leakage was estim.ated to be almost three-quarters of the water supplied to the area. The main source of the leakage was identified as the household plumbing fittings w hich have been badly damaged through constant exposure to a relatively high pressure of 80111. The Khayelitsha Pressure Management Project was therefore proposed in 2001. Using Advanced Pressure Control the average daily flow was thereby reduced from 2,500 1113 /hr to 1,500 1113 /hr representing an annual saving of approximately 40% of the original water use. The Minimum Night Flow was reduced from 1,600 1113/hr to 750 111 3/hr. T he approach used is both simple and innovative and despite the difficulties of on-site construction the savings achieved have exceeded both the Client's and the Project Teams' most optimistic expectations. Local labour was used throughout the project and community support was a key factor in the successful implementation of the project.

This paper gained the Michael Flynn Award for the best platform paper at the 20th AW A Convention.

38

WATER MAY 2003

Figure 1 . Location Map for Khayelitsha.

The project will save in excess of 9 million 1113/year representing a financial saving of more than A$5 million per year at current 2002 water rates - i.e. a 2month pay-back.

Introduction Khayelitsha is one of the largest townships in South Africa and is located approximately 20 km from Cape Town on the Cape Flats. T he area, which was previously a nature reserve, covers approximately 24 km2 and now provides housing to approximately 450,000 people. There are approximately 43,000 serviced sites with both internal water supply and water borne sewage while there are a fu rther 27,000 low-cost housing units

which are supplied from co m munal standpipes. T he area has been expanding continuously since the early 80's when the first settlements were established. The basic water distribution infrastructure is therefore relatively new and is considered to be in generally good condition. Khayelitsha is supplied wi th potable water from Blackheath Reservoir situated at an elevation of 110 111 through two large water mains supplying the area at an average pressure of approximately 80 m (8 Bar). A 1065 mm main supplies water from the north w hile a second 450 111111 diameter pipe supplies the area from the west as can be seen in Figure 1. As the Khayelitsha township has grown, so too has the overall water


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co nsumption as well as the lea kage fi-0111 th e syste111. At the beginning of 2000, th e wate r suppl ied to Kh ayelitsha was almost 22 mill ion 111 3 /a. Th e levels of leakage and/or wastage in an area ca n be estimated from the analysis of the Minimu m Nig ht Flo w (MN F) w hich no rmally occurs between the ho urs o f 2 am and 3 am in th e mo rning w hen m ost of the population are asleep. [n the case of Khayelitsha, the MN F was 111easured to be in excess of 1 600 m 3 / hr w hich is su ffi c ie nt to fill an O lym pi c sized swimming pool every hour. From the analysis of the min imum ni g ht fl ows as we ll as the ni ght-ti111e sewage fl ows, it w as established that most of the water suppE ed to the area was being re turned to the sewer system thro ugh h o use hold leakage. The Khayelitsha Pressure M anagement P roject was therefore proposed to improve t h e leve l of service to t he Kha yelitsha co m munity by red ucing the excessive water pressure and pressure fluctuations in th e reticulation syste111. T h e hi gh p ressures and associated fl uc tu ations over the past 20 yea rs have caused se rious damage to the internal plum bing fitt ings with the result that ho useho ld leakage accounted for m o re than 80% of the nonreven ue water suppli ed to the area. By reduci ng the pressure, it is possibl e to re du ce such leakage and at the sa111e tim e provide a better level of service to t he co nsumers. Th e C it y o f Cape T o wn Administ ration fu ll y supp orted the proposal and endorsed the findings of the Project T eam . T hey agreed to proceed immed iately with a s111all-scale pilot

project in Zone C of Kha yelitsh a (see Fi g ure 1) which was co mmissioned in J an uary 200 I at minim al cos t. T he pilot installatio n was a great success and cl ea rly demonstrated th e benefits t hat ca n be achi eved through pressure ma nagement in Khayeli tsha. T he savings th rough leakage redu ction from the Pi lot Proj ect were estima ted in March 200 l to provide a payback o f less than 6 mo nths . As a res ult of these findi ngs, the C ity of Cape Town Admini stration quickly approved the comm ission ing o f a full -scale proj ect w hic h comm enced in J u ne 200 1 and was com pleted in July

2002.

Scope of the Project In o rder to red uce wastage of water in an area it is first necessary to establish exactly w here t he m ain problem s li e to ensure that t he actions taken are approp riate and effective . In the case of Khayelitsha, the leakage problem was not du e to burst pipes in the distribution sys tem but rath e r to poor in terna l plumbing fittin gs w hich were leaking continuou sly . This co ncl u sio n was reached from the analysis of the m ini mum night flows in to th e area as well as the sewage retu rn flows from the area . It sho u ld be no ted chat the C ity of Cape Town Admi nistration is on e of th e few progressive water supplie rs w hich has a policy of logging and m onitoring both the inflows a nd sewage return flows in selected areas. H aving identified the key source of th e lea kage, the next step was to identify th e 111.ost appro priate course of action to red uce the leakage permanently. In m any other areas with similar leakage problems, the so lution adopted by Co nsultants on behalf of the water supplier often involves retro fi tting of plumbing fi ttings w ithin the properties as the first actio n. While this course of action is appropriate in certain situations, care must be taken to address the unde rlying cause of the prob lem and not simp ly the overlying symptom. In many cases, the inte rnal plumbing fittings are leakin g not just because th ey are of poor quality but rathe r because the system press ures are excessive. If the system pressures are too h ig h, even high quali ty fitti ngs w ill start to leak after a few years. In such situations , t he positive effec ts of retrofitting will be short-lived

Figure 3 . Excavat ing and De-watering t he Site for the 10 65 mm Ch amber.

WATER MAY 2003

39


WATER

and th e leakage levels will quickly return to the pre-retrofitting levels - usually within a year or two. T he solution to this problem is to address the overall pressure problem after w hich the plumbing fittings can be replaced with confidence. It is interesting co note that retrofitting is one of the most costly Water Demand Management measures to implement and , to date, there are few (if any) clear case studies demonstrating the long-term benefits in any water su pply system in South Afri ca . In order to implement p ressure management, it is normally a reasonably simple procedure to install a standard pressure reducing valve . In the case of Khayelitsha, however, the situation was neither straightforward nor simple due to the size of the two supply pipes into th e area. The Project Team decided that the most practical approach wou ld be to cut into the two water mains and comm.ission two installations, each with several sections of sma ll diameter pipe and the appropriate sized PR V's. In this regard it was decided to install three 300mm diameter sections in the 1065 111111 diameter main (Figure 2) and two 200

Figure 4. Internal view of a portion of the 1065 mm diameter chamber.

diameter sections in the 450 111111 dia1neter main. It was also d ecided to introduce advanced pressure control which involves the commission ing of specially imported electron ic controllers which are used to manipulate the pressure 111111

into the area during off peak periods. T hrough the use of such controllers, it is possible to achieve savin gs which are significantly larger than those normally obtained through the PR V's on their own.

Project Implementation

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Email: jamescumming@jamescumming.com.au 40

WATER MAY 2003

QUALITY ENDORSED COMPANY AS/NZS ISO 9001 STANDARDS AUSTRALIA Licence no: 1628

Having agreed on the approach and the conceptual design for the two PRV installations, the most difficult stage of the project was the construction of the chambe rs and the installation o f the mechanical equ ipment. Most of the problems encountered were anticipated to a large degree alth ough the following did cause some problems: â&#x20AC;˘ Shortly after the start of the project Quly and August 2001), the area was hit by severe storms resulting in the wettest two months since records began back in the 1870's. This problem was further aggravated by the sandy soil w hich had to be fu lly dewatered before any excavations could take place. â&#x20AC;˘ Th e C lient was unable to completely stem the flow of water in the pipelines due to leakage at the upstream valves with the result that the pipelin e could not be drained. This in turn caused serio us problems for the mechanica l contractor who had to weld on new pipe flanges after cutting into the pipes. It was on ly through world-class welders working under the most atrocious conditions that it was at all possible to commission the installation. As a result of these problems and others, several major on-the-spot design changes had to be implemented which


WATER

involved qui ck actio n by bo th the Structu ral Engineer as well as the overall Project Manager. Despite the problems, the water supply to Khayelitsha was maintained (albeit at a lower level of se rvice) throughout the cut-in peiiod and no serious complaints were received from the co nsum ers. Som e details of the 1065 mm diameter instalJation are shown in Figures 3 and 4 from w hich the size and complexity of the proj ect can be seen. Fi gure 3 shows the problem s enco untered with the hi gh water table and wet conditions during constructio n which n ecessitated the use of a de-watering syste m since the bottom of the cham ber is more than 6111 below ground level. A b lank flan ge plate can also be seen wh ich indica tes the location of the water main . Figure 4 shows some of the pipe details inside the chamber includin g the valves, 1neters, strai ners and co ntrollers.

Results from the Project When motivating the proj ect to the C lient, the Project Team too k grea t care not to over-emphasise th e li kely savings and not to crea te unrealistic expectations on the part of the C lient. A one-year payb ack was ind icated to the C lient with the proviso that th e savings could be higher de pending on the level to w hich the p r essures ca n be lowered. Despite n1any rou nds of network analysis etc, th e tru e situation ca n only be established through ac tual implem entatio n and it is therefore very difficult to make accurate predictions for a project o f this nature. Another key issue addressed during this proj ect was the accurate auditing of the savings in such a manner that there can be no doubt in the minds of either th e Project Team or the Client. Such auditing is o ften overlooked as an unnecessary lu x ury with the resu lt that many Water D emand Managem ent proj ects cannot be judged properly since claims of large savings made by the Consultant are often not shared by the Cl ient. In the case of the Khayelitsha project, the savings were 1n onitored by the C lient and there is no doubt that the figures quoted in chis paper are factua l. The baseli ne from wh ich th e savings have been calculated is th e level ofl eakage at April 2000 levels when the proj ect was first identified by the Proj ect T eam and presented to the C lient. T he water supply situation in April 2000 had an average flow of2 500 1113/ hr (representing an annual water demand of 22 million 111 3 /a of which approximately 75% was

KHAYELITSHA : Savings from Fixed Outlet Pressure Control

4,000 3,500 3,000 {

~

2,500 2,000

ii:

-Hf--+.-Ht--lr+--h-4-i-l-~-t-t-f.i.-\--l,-+-.J.----++..JA=:+:+:::i::~;::::.:::::i:::::::i::ci::ic..LJ

~--=;M- Wtt/-"Wdff--,lft:ft-1iff-~t-fl-~~~Y.db~!:b~

1,500 1,000 500 !Annual saving • 6 million m'

I

1

o +---~--~--~- - ~ - - ~ - - - - -- - - - - ~1°;;-~""' ~ ·; ·~,;;:-~I Sal

Sun

llon

Tu•

Wad

Thu

Sun

F1i

llon

Figure 5. Inf low to Khayelitsha from Fixed Out let Pressure Control.

wastage) with a Minimum Night Flow of 1,600 111 3 / hr. The first phase of pressure management involved the installation o f th e new pipes and pressure reducing valves (PR. V) with the press ure reduced under fi xed ou tlet pressure control: i.e. the pressure reduced th roughout the who le day using standard PR. V p ressure reduction without any additional reductio n from the contro!Jers. The savings achieved fo r this conditio n are depicted in Figure 5 from which it can be seen that the average daily flow was reduced to 1,800 m 3/ hr with a Minimum N igh t Flow of l ,200 111 3/ hr. T he annual red uction in demand was estimated to be in the order of 6 m illion m 3 /yr. T he second phase of the pressu re co ntro l in vol ved u sin g electronic

controllers to provide further pressure redu ction d urin g periods oflow demand. This form of pressure control is termed Advanced Pressure Control and req uires considerabl e exp erien ce and care to ensure that it is impl em ented properly. The resu lts from ch is stage of th e proj ec t are shown in figur e 6 from which it can be seen that the Minimum Ni ght Flo w was lowered by an additional 450 m 3/ h r to 750 1113 / hr with the average daily flow dropping by a further 300 1113 / hr to 1 500 1113 / hr. The total an nual savings achieved th rough the use of the Time-M odulated P ressu re Control are estimated to be in th e order of 9 mi!Jion 1113 /yr or 40% of the water originally supplied to the area. It is important to note that at no time during th e pressure managem ent activities

KHAYELITSHA : Savings from Time Modulated Control (67m to 38m)

..

4 ,500 4,000 3,500

..

!... . . .:. . . . .•

.. .....:........ :..........!......... :.........1.........1..........1.........

3,000

i'E

2,500

! 2,000 IL

1,500 1,000 500 0 Sat

Sun

llon

Tu•

Wad

Thu

Fri

Sat

Sun

llon

Figure 6 . Savi ngs ach ieved fro m the Advanced Pressure Control. WATER MAY 200 3

41


WATER

was the pressure at any point in the system lowe red b elow th e minimum leve l experienced during normal peak demand perio ds.

Local Community Involvement One of the main problem s often experienced with a proj ect of this nature is the poss ible negative reaction fro m the local communi ty resulting in theft and/ or vandalism of the installation. This is particularly relevant in proj ects in flu encing th e wa ter supply to communities. If the actions being undertaken are perceived to have a n egati ve influence on the overall level of service to th e comm uni ty , the proj ect is destined for failu re no-matter how much effort is spent tty ing to remedy the situatio n. T his potential problem was taken very serio usly by th e Proj ec t T eam and Client from the inceptio n of th e project. The co1nn1.u nity was involved at each stage of th e co nstruction and was continually informed o f progress and pos sibl e wa t e r s hortage s thro u g h contin uo us lia ison with the C o mmunity Liaison Officer. All labo ur used on the proj ec t was sou rced locally wh enever possible and organised through the local labour forum to avoid any complaints of

Figure 7. Completed chamber in Khayelitsha.

favo ritism or nepotism . It was through such m easures that the proj ec t was co nstru cted and commissioned withi n the confines of a low-cost ho using area w itho ut on e incidence o f vandalism or theft.

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An other interesting feature o f th is projec t is th e o ve rall d esign and appeara nce o f the bu il ding Engin eers are not renowned for their flair and imagi nation when it comes to the design of concrete valve chambers and a co ncrete "s hoe-box" is often fav oured without windo ws or an y weak po in ts where entrance can be gain ed. In th e case of this proj ect, however, considerable effort was taken to provide a valve cham ber that wa s both eco nomi cal from a cos t perspecti ve but also as aes th eti c as simple box design can be. An Architect was approached fo r assistance and the end res ult is cle arl y e vi d e nt from th e comp leted chamber as shown in Figure 7.

Conclusions Th e Khayelitsha Pressure Management proj ect was initiated directly as a result of various submissions made to C o un cil by the Project T eam w ho pro vided sufficient mo tivatio n and evidence to support th e investm ent of almost AU$0.5 milJion into th e proj ect. Without th e enth usiasti c support of the WRP team and C oun cil staff from the City o f Cape Town, it is unlikely chat the proj ect would have been approved by the politicians o r accountants w ith in C ouncil. Altho ugh there are already several advanced pressure control install ations in South Africa, the Khayeli tsha project is considered to be the largest of its type in the wo rld with 80 000 conn ec tions over a large area (24 km 2 ) controlled from a single supply. The actual savings achieved are amongst the highest in the world from such an instalJation .


The approach used in the Khayelitsha installation is both simple and inno\'ative and the savings achieved have exceeded both the Client's and the Project Teams' most optimistic expectations. Despite the fact that the installation is situated within a squatter/infonnal area, there was no theft, vandalism or intimidation of any form. This can be attributed to the close liaison between the Council, Project Team and the Local Community who arc all working together with a common goal of reducing wastage. From the Client's perspective, the Khayelitsha project shows not only Technical Excellence but also a true regard for the community and the environment. The project itself, costing approximately AS1 million, will save in excess of9 million 1w3/a representing a financial saving of more than AS5 million per year at current 2003 water rates - i.e. a 2 month pay-back. To place these figures in perspective, the proposed I3erg River Scheme (recently approved to augment water supplies to Cape Town) and associated transfer works are estimated at 2002 prices to cost approximately ASS00 million. This new scheme will provide a safe yield of almost 80 million m 3 /a. The Khayelitsha installation is already saving 11 % of the yield from the Berg River Scheme at less than 0.2% of the cost. As a result of the savings already achieved, the proposed AS8 million extension to the Zandvliet Sewage Treatment Works was 1-ecently Quly 2002) postponed for at least two years saving a further AS 1.0 million per year in net finance charges (i.e. based on interest minus inflation).

Mr Hannes Botha the architect who provided his special "touch" to the appearance of the chamber at no cost to the project. His efforts transformed an ordinary concrete valve chamber into a building that the local community is proud to own.

The Authors Ronnie McKenzie is Managing Director of Water Resources Planning and Conservation (WRP Pty Ltd), a privately owned consultancy in South Africa with about 15 specialists in the water field - mainly working on the planning and management of South Africa's major water transfer schemes with a niche market in leakage reduction through Pressure Management .. ronniem@wrp.co.za. Heinrich Mostert, is Convenor Water Services Reticulation for the City of Cape Town which supports a population of over 3.5 million. I-le has been working in Cape Town for 14 years and was responsible for approving and motivating the Khayclitsha Pressure Management project, heinrich.rnostert@ capetown.gov.za. Willem Wegelin, WR.P Pty Ltd is one of the key personnel at WRP and is responsible for the detailed design and eventual commissioning of all advanced pressure control installations completed by the company. He has completed almost 80 such installations over a 5 year period of which Khayelitsha is by for the largest. willemw@wrp.co.za

Acknowledgements The project described in this submission is a true team effort involving many organisations and individuals. While it is not possible to mcntion everyone who played a role in the successful completion of the projt·ct, it is considered appropriate by the Project Team to mention a few individuals without whom the project could not have taken place. The authors thank the following: Councillors fro111 the for111er City of Tygerberg and present City of Cape Town (in particular Alder111an Sitonga: formerly Mayor of Tygerberg) for their support of the project at a political level and providing the Project Team with the opportunity of developing such a prestigious installation. Mr Charles Chap1nan, former Water Demand Management Manager for the City of Cape Town who actively supported the project from its inception. Mr Anic Smit from the City of Cape Town who together with the authors recognised the potential for reducing wastage in Khayelitsha and actively motivated for a major pressure management project in the area. This project is considered to be the first main step towards the long-term goal of providing a more sustainable water supply to all Khayelitsha residents. Mr Tertius de Jager and Mr Larry Cronje; (also from the City of Cape Town but based in Khayelitsha), for their continued support and enthusiasm throughout the project. As the Client's representative in Khayelitsha, their active involvement in the project contributed greatly to its success. They are also one of the very few teams in South Africa to monitor both flows into their supply area as well as sewage return flows out of the area Mrs Portia Mabece, the community liaison officer for Khayelitsha, who worked continuously throughout the project to maintain communication and good relations between the community and the Project Team.

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43


m

WATER

ADVANCED REUSE - FROM WINDHOEK TO SINGAPORE AND BEYOND I B LAW Abstract Advanced reuse, and the subsequent use of the reclaimed water to supplement a co mmunity's water supplies, is a topi c that often eli cits debate between professionals and lay-people alike; and this has been the case ever since the first such facility was commissioned in the 1960s. T he 'precautionary principle', a term described by some as being a reason for doing nothing, is certainly applied to this form of water supply augmentation. This is despite the fac t that such schem es al ways incorporate m ore 'treatmen t barriers ' than are provided in many conventional water treatment systems that draw from raw wa ter suppli es of dubious quality. Nevertheless, there has been m uch achieved in the field of Advanced R euse and this paper provides an overview of developments since the world's firs t direct potable reuse plant was commissioned in W indhoek, Namibia in 1968 .

application in the treatm.ent plants; as highl ighted by th e recent NEW ater plan ts in Singapore. The paper concludes w ith a look into the future - what shou ld be done and what is li kely to be achieved in this important area of Advanced R euse.

"A Nation that fails to plan intelligently for the development and protection of its precious waters will be condemned to wither because of shortsightedness. The hard lessons of history are clear, written on the deserted sands and ruins of once proud civilisations"

Advanced Reuse Milestones Mu ch has happ ened sin ce the W indhoek Plant was commissioned in 1968. Salient milestones are: • T he world's fi rst D irect Potable R euse plant was started up in Windhoek, Namibia in 1968 using techno logy that was available at that time . Th is plant has undergone many technological changes since then. • Reverse O smosis (RO) was first applied in 1976 at Orange Co unty Water District's (OCWD's) W ater Factory 21. • T he world's first Plan ned Indirect Potable R euse (IPR) schem e, in volving

Lyndon B. Johnson, 36th President of the USA It notes that the improvement in the technologies applied has generally been driven by the increase in analytical capability and that, in line w ith this, membrane systems are fi nding increasing

First Use of Reverse Osmosis

Water Factory 21

First On-line Monitoring Techniques for MF & RO

First Use of Ozone and GAC in Water Reclamation

Scottsdale

West Basin San Diego Aqua 2000

Pretoria

I 1968

1976

Windhoek

World's First Direct Potable Reuse Applicstion

1978 1979

I I ,.

Cape Town UOSA

First Surface Water Augmentation

I 1994

WATER MAY 2003

1996

Water Factory 21 , USA

First Demonstration of Microfiltration for GWR System

Figure 1. Salient Milestones in Advanced Reuse Applications .

44

GWR System

Gwinnett County Flow Augmentation

Singapore NEWater

Comprehensive Health Effects Study


WATER

the return of reclaimed water to a surface wa ter reservoir, was commissioned in 1978 at Uppe r Occoquan Sewage Authority (UOSA) plant in North Virginia, USA. • Ozone coupled with activated carbon was first trialled in a water reclamation context in ·1978 at the 5,000m 3 / day Stander Plant in Pretoria, South Africa • The first use of long term health effects testing was com menced in 1983 at the Denver Pilot Plant using both rats and 1T1.ice . • Mi crofi ltration (M F) was first applied as a pretreatme nt stage to R O in 1993 at OCWD's Water Factory 21. • On- line moni toring techniques for MF and RO systems were developed and tri alled in 1996 as part San D iego 's Aqua 2000 research programme. • A Membrane Bioreactor (MBR) was first applied as a pretreatment stage to RO in 1997 at the McAllen Plant in Texas,

us. • Singapore's NEWater lO,000m 3/ day Demo nstration Plant, in corporating the M F / RO /U V t rea tm en t train was commissioned in 2000. • A MF/ RO plant was commissioned at Luggage Point , Brisbane supplyin g high q u ality reclaimed water to an adjacent oil refinery • A 2 year h ea lt h effects testing program me, using both fish and mice for th e first time, was started in 2000 in Singapore. • The MF / RO / UV treatment train is ad opted in Singapore, with two full-scale NEWater plants operational in 2002, initially serving the high-tech industry, but w ith indirect potable re-use being implem ented in February 2003 . A summary of these and some other Advanced R euse m.ilestones is presented in Figure 1. Figure 2 shows the growth in microfiltra tion membrane applications for both surface wa ter and water reclamatio n plants over the p erio d 1990 -1999, showing the exponential growth in m.embrane usage. T his growth is best exemplified by the following: 1994 - there w ere two MF /UF m anufacturers w ith installations greater than 2,000 m 3 / d 1994 - the largest municip al MF /UF plant h ad a cap acity o f 20,000 m 3 / d 2002 - there w ere eleven MF / UF manu fac turers ac ti ve i n th e municipal m arke t 2 002 - the largest municipal plant was 100 ,000 m 3 / d

Figure 2. Growth in the Membrane Filtration Market.

2004 - a 300,000 m 3 / d facility will be on-line

Project Drivers and Technologies Applied

O ne adva ntage o f this exponencial growth in m embrane appli cations is th at the un it cost of the fac ilities has been decreasing, w ith the result that the unit cost o f reclaimed water produced from such plants is also decreasing and, in many locations, is now competitive with other sources of water.

Why did these advanced reuse projects pro ceed and w hat technologies did they use ? T hi s Section addresses these questions. Project Drivers The drivers for four notable advanced reuse projects - W indho ek, UOSA, OWCD's Groundwater R eplen ishment

Table 1. Project Drivers Windhoek:

Low rainfal l, high evaporation , low runoff

Al l surface water sou rces within 500 km of the city had been exploited

Further wate r sources were expensive and obtaining them controversial

Maximum groundwater utilisation was already occurring

Demand management had already been implemented

No other option but wastewater reclamation

UOSA:

• Indirect Potable Reuse occurred as a result of development and population growth in the area • Qual ity of water in t he receiving water (Occoquan Reservoir) was deteriorating •

On-going IPR necessitated maj or upgrade to quality of reclaimed water

OCWD's GWRS:

Demand management - implemented, but still will not meet the projected water requirements

Seawat er desalination - too expensive, compared to GWRS

Additional percolation basins - no land

Agricultural transfers - too difficult, no water rights

Purchase additional imported water - costly, may not be available

• Groundwater replen ishment using reclaimed water - cost effective, reliable and with added environmental benefits. Singapore:

50% of the Island's fresh water supplies are imported from Malaysia

• This su pply is subject t o on-going negotiations •

Steps taken to reduce reliance on th is large supply, through sea water desalination and water reclamation (NEWater)

WATER MAY 2003

45


WATER

"J;,Ji,.ter should be judged not by its history but by its quality" Dr Lucas Van Vuuren, pioneer of water reclamation research in South Africa in the 1970s. System (GWRS) and Sin ga p o r e's NEWater initiative - are summarised in Table 1. [twill be noted that W indh oe k and OCWD's GWRS have similar drivers, with perhaps the most important being that additional wate r had to be found to meet future demand and water reclamation was deemed the most appropriate way to go. UOSA was driven more by a receiving water quality requirement and Singapore by a n eed to secure its water supplies into the futur e. Technological Change It is unlikely that the treatment train cha t was initi ally implem e nted at Windhoek in 1968 wi ll ever be used again ; it was considered appropriate at th e time but would fall far shore of acceptance today. There have been four technology changes/u p grades at Windho e k sincel 968, with the most rece nt being in 2000 w he n , amongst ocher changes , an ultrafilcration (U F) me mbrane filtrat ion system was installed. The treatm ent trains adopted at th e Windhoek, UOSA and Sin gapore plan ts are presented in T able 2 for comparison. OCWD's GWR System, the fi rst phase of which is due to be operational in 2004 will use a treatme nt train simi lar to that being used in Singapore; dual membranes fo llowed by UV disinfecti on. T h e trend towards m e m bra n e treatment systems is clearly shown. le is of in terest to note that OCWD's original reclamation plant - Water Factory 21 - used a treatment train similar co that used at UOSA as pretreatment for the reverse osmosis units; high lime fo llowed by reca rbonation and sa nd filtration . R esearch into the use of microfiltration m e mbranes clearly showed an added benefit of these systems over the more traditional lime syste m - land area required reduced by 75% and operating and maintenance costs reduced by 50% (Leslie et al 1998) Health Effects Studies T echnology is one part of the equation. Proving that it works and that the reclaimed water is safe and wholesome is th e other. These studi es into health effects evaluate both the short and long-term 46

WATER MAY 2003

Table 2 . Comparison of Technologies Windhoek

Windhoek

UOSA

1968

2000

1 974

2002

Secondary Treatment followed by:

Improved Sec Treat followed by:

Secondary Treatment followed by:

Secondary Treatment followed by:

• High lime treatment

Algae f lotation

• Pre-ozonation (for Fe and Mn)

Singapore

• Foam fractionation

• Dissolved air flotation

• Clarification

• Membrane filtration (MF or UF)

• Chem Clarification

• Sand filtration

• Recarbonation

• Reverse Osmosis

• Ozonation

• Sand fi ltration

• UV Disinfection • Stability control

• Sand filtration

• GAC

• GAC

• GAC

• Membrane fi ltration (UF)

• Ion Exchange

• Chlorination

• Chlorination

Reclaimed Water Flow: 82 ML/ d Reclaimed water contribution: 1% initially and increasing

• Chlorination

• Chlorination Reclaimed Water Flow: 4.8 M L/ d

Reclaimed Water Flow: 21 ML/d

Reclaimed Water Flow: 200 ML/d

Reclaimed water contribution: 4%

Recla imed water contribution: 25%

Reclaimed water contribution: 1045%

health effects and they generally include exten sive sa mp ling and monito ri ng programs coupled with i11-vitro and/or i1111i vo toxicological studies in some shape o r fo rm. A comparison of the health effec ts studies carried out at Windhoek, UOSA , Water Factory 21 and Si ngapore is presented in Table 3. The H ealth Effec ts studies carried out as part of the NEWater 'proving period ' in Si ngapore were th e first in the world to use two differe nt species - mice and

fish. Using fis h is in line with the gro wing trend worldwide as chis does obviate the necessi ty of having to concentrate the

organics, as is required for the mice alternative. An extensive sampling and monitoring program was also incorporated in the Singapore studies. This program \-Vas ca rri ed out over a two and a half year period and monitored fo r a range of parameters at a number of locations. le was updated with 'new' parameters as they became ' known ' - s u c h as N nitrosodim ethylamine (NDMA) and I ,4 Di oxan e. The number of parameters analysed, by location, is summarised in Tabl e 4 . The freq ue ncy of analysis va ried for each param eter; so me weekly, so me monthly and some quarterly. It can be seen that,

Table 3 . Comparison of Health Effects Studies Windhoek

UOSA

Water Factory 21

Singapore

Toxicological Stud ies:

Toxicologica l Studies:

Toxicological Studies:

Toxicological Stud ies:

• Ames test

• None to-date

• On-l ine biomonitoring using Medaka fish tested.

• 2 year in-vivo chronic toxicity study with mice

• Urease enzyme activity & bacterial growth inhibit ion • In-vivo studies include water flea lethality and fish (guppy) biomonitoring

• 2 generation study with Medaka fish

Epidemiological Study (1976-1983) Sampl ing & Monitoring Program

Sampli ng & Monitoring Program

Comprehensive Sampling & Monitoring Program

Comprehensive Sampl ing & Monitoring Program

On-going quality monitoring

On-going quality mon itoring by an independent panel of review

On-l ine fish biomonitoring with external review panel

On-going quality monitoring by an independent panel of review


WATER

w ith chis extensive database o f results and t h e results from the H ealth Effects Study, t h e G overnme nt had a so und basis o n w h ich to base the ir decision co proceed w ith planned indirec t potable reuse .

Table 4. Singapore's Sampling and Monitoring Program.

Facts, Perceptions and Opinions

"=

T he practi ce of re turning reclain1ed w ater co a reservoir to au gm e nt wa te r su pplies- be it surfac e w ater o r grou ndw ater - has certainly c rea ted muc h debate and disc ussion in both th e professi o nal and lay sectio ns of our so cie ties. T h e r e a r e m an y in s ta n ces of U npla n ned In d irec t Potable R e u se ( UI P R.), whe reby created m un ic ipa l wastewate r and som etim es, untreated agri cul tura l o r ind ust ri al wastes are re turned to a water body upstream o f an o ff- cake fo r a dri nki ng water treatm ent plant, being practiced in th e world to-day. E xa m ples include the Yangtze l<...iver in C h ina , the T ham es R iver in the U K , the M .urray- D arl ing and N e pean Ri vers in A ustralia, th e Rh ine R iver in E urope and th e Miss iss ippi and Santa Anna R ive rs in th e U S. Problem s, in terms of drink in g w ater q ualicy, have occurred in these and other U J PR applicatio ns as a resul t o f th e natural assimi lative capac ity of th e r ece i v i n g wa t e r bod y b ec om i n g o verwh e lm ed as waste inl'lo w s inc rease w ith tim e. In addition , the increase in the u se of synthe ti c chem icals has resulted in s u ch che m icals o fte n being prese nt in the d rinki ng water as they are generally poo rly r e mov e d wit h c o n ve n tion a l wat e r t rea tm ent technologies . Stander ('I 979) ,often referred to as the fa ther o f research into water reclamation a nd reuse in South Afri ca, stated , over 20 years ago, that: " It can be uneq uivocally state d that situations repo rted o n the inc ide nce o f m icro-organics in drinki ng wate r are largely due to an o ver assessm ent of fi rstly, the capacity of self- pmificatio n processes and o f the ro le of dilution o f th e water environment in degrading and dissipating these com po unds an d seco nd ly, the adequacy of the physical chemical u n it processes of con ventional w ater purification systems co rem ove compo unds w hich arc present in the raw water intake at m icro-concentratio n levels".

T he co rollaty co chis is that if treat m ent is impro ved at th e waste water treatme nt p lants, if industrial wastes are controll ed ( o r d iverted) and if tota l catchme nt co ntrol procedures are implem e nted , t h en the q uality o f the rece ivi ng w aters a nd hen ce th e raw w ate r suppl ies to downstream w ate r trea tme nt plants mu st improve .

W nter Q uality P ara met er

PUB NE Water PUB Raw RO UV MF P !ant (S) Wa ter Dri nking F ecd wa tcr Fi lt ra te Per mea te Efflu ent Wa ter (I ) (4) (2) (3)

9

9

9

2

6

6

6

34

38

38

38

21

21

21

21

2

9

Physica l Dis infec tion Bypr odu cts

6

In or ganic - 0 ther

38

Disinfec tion Byprodu cts

21

O th er Co mpo unds

40

40

40

40

Pestic ides/ He rbi cides

49

49

49

49

R adionuclid cs

6

6

6

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Wastewater Signatur e Co mpo und s Sy nth etic & Natural Horm on es

3

3

Micr obio log ica l

I0

6

183

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17

69

3

10

6

3

186

182

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additio n , th ese dri nkin g w ater standa rds ge nerally cover o nl y a limi ted nu mbe r of conta m inants. T hi s apparent co n l'l ict is often raised as reaso n no t to proceed w ith potable reuse but it can be take n to t he extreme. For example, many co nventio nal so urces of fres h wa ter are beco m ing so contami nated chat wate r recla imed fro m a m uni cipal e ffi uent can be of a superi o r q ual ity and be a pe rfectl y adequate so urce of w ater - plan ne d in direc t potab le reuse is viable in ch is case . An e xa mple of the di ffere nce between a conta minated surfa ce w ater and a hig h quality reclaim ed water can be taken fro m Orange C ou nty, C alifornia w he re the foll owing o rga nic compounds have bee n

T h ere are now m any e xamp les of advanced water reclamation plants that have reliably p roduced a reclaimed water of a qual ity that is eq ual to or be tte r than th at o f the local raw water supply o r d rin kin g w ater - San D iego , Den ver, Cape Town , Preto ria, Wind hoek, Wate r Factory 21 ... and no w NEWater in Si ngapo re . H owever, co mpliance with drinkin g water standards is not always cause co state that a rec laim ed w ater is sa fe as th ese standards are intended fo r water obtained from relatively uncontaminated so urces of fresh water, and not fo r a reclai med w ater o btai n ed fr o m a n e ff1ue n t fr o m a m u nicipal waste water trea tment plant. In

Occurrence of Organics of Wastewater Origin Orange County Santa Ana River 1

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1. Sampled downstream of Prado wetlands 2. Feed water: Clarified secondary effluent : Product water RO permeate Figure 3. Occurrence of Organics of Wastewater Origin.

WATER M AY 2003

47


WATER

used as signature compounds for con t am in ation wit h muni c ipal wastewater (Leslie et al 1999): • Et hylen edi a mine tetraaceti c ac id (EDTA) • Napthalene dicarboxylic acid (NDC) • Nitroloacetic acid (NT A) • Alkylphenol polyethOll.')'lates (APEO) and carboxyla tes (APE C) Figure 3 compares the o ccurrence of these organi cs in the Santa Ana River in sout he rn California with the Orange Coun ty Sanitary District secondary effluent (the feedwater to the Water Factory 21 water reclamation plant) and the p e rmeate from th e reverse osm osis plant at W ater Fac tory 21 (Leslie et al 1999) This Fig ure clearly shows t he higher quality of t h e reclaimed water as compared to th e Santa Ana River and lends support fo r th e concept of i ndirect potable re use. It is pleasing to see professional bodi es and other organisa tions agreeing that indirect potable reuse can play a ro le in prolonging water supplies. For example, the Executive Committee of the Water Environm e n t Fe de ration (WE F) approved the fo llowing state m e nt in October 1998 : WEF recognizes that th e world's water supply is a finite resource and the practice of water reuse is key to the conservatio n of this natural resource. Thu s, W EF su pports the use of rec laimed wate r for no n- potable purposes as a means of conserving potable water supplies. Also, WE F supports th e consideration and use of highly treated reclaimed water for indirect potable reuse and encourages public involvement in all aspects of water reuse projects. The reuse of municipal wastewater for beneficial purposes is an important element of the world's tot al w ater r eso ur ces management. The use of reclai111ed wa t er fo r domestic, indu strial , co111mercia l, agri cultura l, environmental, and other purposes can conserve and extend freshwater suppli es. Indirect potable reuse is the introduction of highly treated reclaimed water co a surface water or grou ndwater system that ultimately is used as a pot abl e water sup pl y . C urre n t engi nee rin g pra ctice can provide treatment syste111s that are capable of rel iably eliminating pathogens and reducing organic and inorganic contaminant concentrations to very low levels in reclaimed water. Therefore, local authoriti es should consider indirect potable reuse of reclaimed water as part of an integrated water reso urces

48

WATER MAY 2003

management strategy. The viability of reclaimed water for indirect potable reuse should be assessed with regard to quantity and reliab ility of raw water supplies, the qualiry of reclai111ed water, a n d cost effect i ve n ess . These management criteria should always be used in decision making related co the use of highly treated reclaimed water for indirec t potable reuse. Owners and operators of wastewater treatment systems producing reclaimed water fo r beneficial applications are urged to adopt the attitude that they are performing resource recovery rath er than wastewa ter disposal and that their operations have public health significance. WEF also urges owners and operators of wastewater treatment systems and reclaimed water use areas to provide public educatio n programs and in volve the public in the plan ning, development, and operation of water reuse projects. The USA National R esearch Council (1998) stated t hat: Our genera l conclusion is that planned, indirect po table reuse is a viable application of reclai med water but only wh en there is a careful, thorough , project-specific assessment that includes contaminant monitoring, health and safety testing and system reliability evaluation . Further, i t goes on to state: Indirect potable reuse is an optio n of last resort. It should be adopted on ly if other measures - including other water sources, non-potable reuse and water co nservatio n - have been eva luated and rejected as technically or economically infeasible.

Technology Driven by Increasing Analytical Capa bility

"Ulater sustains all " Thales of Miletus, 600 BC D espite the fact t hat o ur analyti cal capability has in creased immensely in recent tim es we can still o nly identify and quantify individually so m e 10-15% of the residual organ ic fraction in a reclaimed water. It is fo r this reason that R egulato rs often specify surrogate parame te rs (suc h as· Total Organic Carbon , TOC) as well as .treatme nt technologies for advanced reclamation and reuse applications. I mp r ovements in d etec ti o n techno logy now allows us to d etect known contaminants at mu ch lower levels and also to 'discover new contam inants'. T his abil ity has in some instan ces

confirmed the presence of trace organics at low concentrations in both surface and reclaimed w aters - compo unds such as NDMA , 1 ,4 Dioxane an d those chemicals that are classified as endocrine disrupting compounds (ED Cs) being examples. T his has resulted i n a review of the appropriate level fo r the TOC surrogate as we ll as an added requirem ent fo r appropriate treat m e nt technologies for those co ntaminants not c ontributing to TOC, such as NDMA . F o r exa mpl e, the Ca l iforn i a D e pa rtment o f H ea lth Services is considering additional treatment and assay requirements for any groundwater recharge proj ects in that State w hich result in m o re than 50% of reclaim ed water being in the groundwater basins. The regulatio ns are expected to include a TOC of less than 0 .5 mg/ L of wastewater o rigin w ith additional testing for specifi ed tra ce o rga ni c compounds , post RO trea tment with advanced oxidation using UV and hydrogen peroxide, and possibl e in -vivo bioassay (T suchihashi R et al 2002) T his likely reductio n in TOC values and g reater emphasis on treatment tech no log ies will su rely support the trend towards the use of m embranes as a core techno logy in future advanced water reclamation plan ts. H owev e r, we mu st k ee p this im p ro ve d analytical cap ab ilit y i n perspective . T he levels of trace organic compounds in reclaimed water must be compared w ith the levels fou nd in other sources to eval uate th e true significance of using the reclaimed water for human consumptio n . It has been shown that w ith the exception of NDMA, intake of m ost chemicals through ingestion via t he water ro ute could be less sig nificant than the in take from other sources such as food (T suc hihashi et al 2002)

Into The Future How will the tim eline presented in Fig ure 1 look in th e next decade or so? What developm ents can we expect to see on both the macro and micro levels? Starting at th e macro level , it is, to the author's mind, a given that there w ill be an increase in th e number of locations around the world that w ill e ither be pla nning, or w ill already have pla nn ed and implem ented, advanced reuse systems. T here w ill be pressure o n those 1111pla1111ed IPR appli cations to reve rt to th e more responsible pla1111ed alternative as a m eans of prote cting the quality of water distributed to th e public


WATER

a nd of 111aximising th e so m e tim es meager fresh water supplies available in ni.any countries. Advanced reuse has already become a co rnerscone of th e practice of Total Water Management. Total Water Mn11nge111e111 (TWM), a te rm that is often interchanged 111itl, vVnter Cycle Mn11nge111ent or fttt egmted f!Vnter Mn11nge111e111, will be a com111on practi ce as it focuses on creating va lue for a commodity chat is esse ntial to our surviva l. It also stri ves to introdu ce the issue of 's u stainability' into our manageme nt procedures, with t he overall ai111 of being co safeguard the m eager freshwater supplies that exist in many parts of our world and yet still cater for increasing popu lations and economies. TWM (Law 2002) covers th e following tenets • Water is viewed as a resource co be used and reused - essentially speedi ng up the water cycle; • Stormwater is viewed as a resource rather than a 'waste'; • Water demand is managed concurrently with supply through conservation, pricing and incentives; • Higher levels of wastewater treatment are provide d with the volumes released back into the environment being greatly reduced; • Catc h ment or Wat e r shed M anagement is an integral compo ne nt; all point and non-point sources are id e ntified and managed; • Ecosystem managem ent important environmenta l flows identified a nd catered for; • Total integration of water, air and land issues; • Bioso lids reused, not disposed; and • Water is used to create recreational and aes th e tic foca l po in ts for the community. There will be many instances of recla imed water being incorporated into Aquifer Storage n11d R ecovery (ASR) schemes, w hereby it is injected and stored in groundwater aqu ife rs fo r subsequent abstraction and reuse much along the lines of schemes already exist around the world - in the UK, the US, Taiwan and Australia co nam e but a few . This practice serves co augment d wi ndling groundwater supplies w hile at the same time affording an extra ' b arrier' of treatm ent co the reclaimed water (T oze et nl 2001) - an important aspect if the abstracted water is co be used as a potable water supply.

There w ill be increased application of

Sel/ler Mi11i11g for advanced reuse appli-

infrastructure work being planned for the Beijing 2008 Olympic Games.

cations in cities. Sewer mining involves drawing raw wastewater or treated e illuent from a n1.ajor trunk or carrier sewer direct into a 111embrane-based treatment plant. Th e eilluent fro111 such a plant is then reused in adjacent industries, houses, public am enity areas etc with all by-products of the treatment process being returned co the sewer for subsequ ent processing at a centralised WWTP.

On th e micro scale, on-going research into copies related to advanced reuse is required and a sunm1.a1y of chose topics suggested by the Na ti onal R.esea rch Council in 1998 is:

Sewer mining has the dual advantage of not only being located near to the 'point of reuse' but of also reli eving the hydraulic load on existing major sewer systems. The system was first applied in South Africa in the 1970s w ith the Alexandra plant and in Australia with the membran e-based facility install ed in Canberra in 1994. D evelopm ents in 111e111branes over the last decade or so has spawned i ncreasing interest in the system in Austral ia - in Melbourne and more recently in Geelong. T he system is also being considered as part of the

• Con tinu ous (on-lin e) toxicological testing

E A

R T

• D etection of em erging pathogens • Better indicator organisms • R apid on-line 111011itoring techniques • Organic chem ical identification & fate • T reatment performance and reliability

• Effect of dilution, so il interactio n , and aquifer inj ection on organic che mi cals • Effectiveness of enviro nmental buffers To this list co uld be added ' effective publi c communica tion and educa tion programmes'. There are obviously many sub-sets to each of the above and they wi ll all ha ve to be addressed to ensure that advanced reuse is viewed as a safe and sustainable way forward .

H

T

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t wa er

total

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Water Recycling Asset Management Water & Wastewater Technology Catchment Management Risk Management Infrastructure Planning Strategic Partnership 200 Offices Worldwide Australia Asia Pacific Head Office 71 Queens Road Melbourne + 61385179200 www.earthtech.com .au

WATER MAY 2003

49


WATER

Conclusions The freshwater supplies in the world are fi nite and unfo rtunately we have not regarded them as such. W e have poll uted and over-used th ese precious resou rces and unl ess we act now, the futu re generations w ill not than k us. Advanced reuse systems do have a rol e co play in securing some of our water supplies into the future. M uch has been do ne and w e have some 'trophy' projects either operating o r under design; but there is still a lot to be done . Wh ile we have the technology to produce whatever quality is required, we do have to ensure that all regulators, water professionals and the community-a t- large accept planned indirect potable reuse as a viable way of augmenting o ur dwind ling fresh water suppli es - this is the ultimate challenge.

The Author Ian Law was, until recently, the T ec hnology Director w ith C H 2M HILL Australia Pty Ltd and has been involved in water reclamatio n in So uthern Afri ca , S E Asia and Australia. H e was responsible for C H2M H ILL's role in developi ng the N EWater projects in Singapore. Email: ilaw@ ch2m. com.au , or alternatively iblaw@bigpond. com

References Law I B (2002), 'Total f,f/ater 1\l/miage111e11t - the F11t11re is Now' Paper presented at the C IWEM lnternational Conference on W astewater Manageme nt & T echnologies for Highly Urbanized C oastal C ities 2002, Hong Kong, June. Leslie G L, M ills W R., W ehner M P, Rigby M G, Dunivin W R and Sudak R G (1998), Trear111e11t Costsfor M e111brm1e Processes i11 W ater Reuse

The Water Corporation is one of Australia's largest and most successful water service providers, which services approximately 1. 7 million customers. We provide a flexible working environment and opportunities to develop stimulating careers.

Senior Engineer - Albany â&#x20AC;˘ Asset Management â&#x20AC;˘ Coastal Lifestyle, Western Australia An opportunity has arisen in our Assets Section for a Senior Engineer to help maintain the Great Southern Region's asset base, which comprises two major water supply schemes, 27 treatment plants, 8 dams, 2 desalination plants and Australia's largest effluent disposal tree farm. The successful applicant will ensure infrastructure is in place to meet the changing needs of our customers whilst assisting with new asset management initiatives undertaken by the Region. This role is also responsible for developing forward thinking asset management strategies and devising new methods of generating income for the business. This position requires a degree in mechanical or civil engineering with considerable experience in asset creation, operations and maintenance of water industry assets. A proven track record in asset management together with excellent technical report writing, problem solving, analytical and computer skills are also necessary. A current C (formerly A) class drivers licence is essential. The annual salary ranges from $58,124 to $73,837 and will be negotiable depending on skills and experience. Please forward your application, including a covering letter, a statement addressing the above requirements and your current resume to Barbara Thomas, Human Resources Branch, PO Box 100, Leederville 6902 oremail to barbara.thomas@watercorporation.com.au. For more information please contact Rod Collins on (08) 9842 4214. Applications must be received by 4.00pm 22 May 2003.

"Our po/Icy Is to respect and protect your privacy." 50

WATER MAY 2003

A pplications; A Se11siti11it y A 1ialysis. Proc. American D esalting Associatio n Biennial Con ference & Exposition , W illiamsburg, Virginia, August. Leslie G L. Dawes T M , Snow T S, M ills W R .and MacI ntyre D (1999), Meeting tfte De111m1dfor Potable Water i11 Orange Co1-111ty in tfte 2'/st Ce11111ry: TI1e R ole ofMe111brm1e Processes. Proc. American Water Works Association, M embrane T echnology Con fere nce, Lo ng Beach , CA, March Natio nal R esearch Council (1998), lss11es i11 Potable R euse - Tlte Viability of A 11g111euti11g Dri11kit1g Water Supplies 111irlt R ec/ait11ed Water, National Academy Press, Washington D .C. Stander G J (1979) 'M icro- Orga11ic Co111po1111ds i11tlte Water E1wiro11111e111 a11d tlteir l111pact 011 tlte Q 11ality of Potable Warer S11pplies' Paper p resented at the 26th Convention of th e Souch Afri can C hem ical Institu te, Port Elizabet h, South Africa T oze S, D illo n P, Pavelic P, Nicholson B and G ibert M(200'1), Aquifer S torage a11d R ecovery: Re111cwal of Co11ta111i11a11tsfro111 S tored vllater, Water, 28, 7, O ctober. T suchihashi R , Sakaj i Rand Asano T (2002), Health A specrs ,if Gro1111d11mter R.echa~~e 111itlt Rec/ai111ed f,f/a/er, Pape r presen ted at 4t h International Symposium o n Artifi cial R echarge of Groundwater, Adelaide, Australia.

BOOK REVIEW Waterwise H ouse & Garden. A G uide for Susta.i nable Living . CSIRO Publishing. ISBN O 643 06800 7 Available from AWA bookshop $29.95 plus p&h. Contac t bookshop@awa.asn .au Drought or flood? Australia is one of those continents dogged by extremes. This little book on using water sustainably has been published at an opportune time for most of the eastern states and fo r parts of the south- west. Allan Windust, better know n as a "wo rm expert", has put together some of the well known and many lesser kno w n initiatives that individuals can take to ensure that they ca n maintain a healthy, well nourished garden witho ut feeling the need to breach mandato ry water restrictions imposed in some shires. T here is the usual list of"can do 's" such as using timers to limit watering by automated systems, buying a moisture meter to test soil moisture prior to hosing, using tank water for cisterns and recycling household wastewater: and many more. A multitude of facts too on planning the water-wise garden, growing plants, using m ulch, and detailed lists of dry climate tolerant plants. T here are a few extra little gems which can be gleaned from Waterwise House & Carden. For example: Did you know that treated greywater can be used on the garden during dry weather because after rain, it may be transported onto neighbouring properties. Further, you sho uld also avoid using additional fertilizer when applying greywater. Another w ater saving suggestion : In J apan you can buy a hand basin / toilet set in which the hand basin feeds wastewater directly into the cistern. The only contaminant in the hand basin is soap which does not pose a health risk. U nfortu nately, no enterprising Australian firm has yet sought to impo rt o r develop an Australian version. T his book is excellent value and its cost is recouped in savings on the household water bill. H ighly recommended.

D iane Wiesner AWA snr scientist

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Water Journal May 2003  

Water Journal May 2003