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< 1,000 (gpm)

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Volume 31 No 1 February 2004 Journal of the Aus tralian Water Association

Editorial Board F R Bishop, C h airma n B N A n d erson , W J Dulfer, G Finke, G Finlayson, G A H olde r, B Labza, M Mumisov, P N ad ebaum , J D Parker, F R o ddick , G R yan , S G ray, A Gibson

'- Water is a refereed journ al. This symbol indicates th at a pap er has b een re fereed.

Submissions In structions for amh o rs can be fo und o n page 3 o f th is journal. Submissions accepted at: www. awa.asn.au / publications/

OPINION 2

Water Education · at a Watershed; Virtual Water · Not to be Ignored; My Point of View, River Health: Challenges We Must Meet, P J Crawford

ASSOCIATION ACTIVITIES 6

Including IWA Australia Report and WEF Report

PROFESSIONAL DEVELOPMENT

Managing Editor Peter Stirlin g

10 Details of courses, classes and other upcoming water events

Technical Editor

CROSSCURRENT

E A (Bob) Swinto n 4 Pleasant View C res, Wheelers Hill Vic 3 150 T el/ Fax (03) 9560 4752

14 Featuring selecled highlights from the AWA Email News

CONFERENCE REPORTS

Email: bswinto n@ bigpond.nec.au

18 ICAM 2003, A Cha n a n

Water Production

WATER DISINFECTION FEATURE

Hallmark Editio ns PO Box 84, Hampton , Vic 3188 Level 1, 99 Bay Street, Brighto n, Vic 3186 T el (03) 9530 8900 Fax (03) 9530 8911 Email: hall111ark@ halledit. co111.au Graphic desig n: Mitzi Mann

19 UV INACTIVATION OF MICROORGANISMS IN WATER · A REVIEW It's resistant to chlorine, but not to UV J L Cla ncy, TM Hargy

22

Water Advertising

G L Bolton an d J M Hoope r

National Sales Manager: B ria n Rault T el (03) 9530 8900 Fax (03) 9530 8911 Mo bile 04 11 354 050 E111ail: b rault@ halledit.com .au

26 ENVIRONMENTAL AND WATER TREATMENT PROCESSES THAT CONTRIBUTE TO MICROBIAL DESTRUCTION · HIDDEN SOURCES OF DISINFECTION CRCWQT investigate what happens in nature A R Keegan, PT Monis, D Damina to, P Cox, H Bustamante, C P Sa in t

Water (ISSN 0310 • 0367) is publ ished e ight ti111cs a year in the 111o nth s of February , March, May, June , Aug u st, Septe mber, Novem ber and D ecembe r.

WATER 33 WATER - SECOND AND THIRD TIME AROUND Recycling: a review of the current situation

Australian Water Association PO Box 388, Artarmon, N SW 1570 Tel +6 12941 3 1288 Fax: (02) 94 13 1047 Email: info@awa.asn.au ABN 78 096 035 773

Federal President Rod L e hmann

Chief Executive Officer

·, SELECTION OF A UV DISINFECTION SYSTEM FOR BUSSELTON WATER Medium Pressure UV but no residual, for a groundwater

AWA

~

JC Radcl iffe

36 AUSTRALIAN WATER CONSERVATION AND REUSE RESEARCH PROGRAM Explores the gaps in our knowledge P Dillon, D Ellis

40 INTEGRATED WATER MANAGEMENT - PUSHING THE BOUNDARIES It not only saves water, but money as well N Aposto lidis

AUSTRA LI AN WATER

ASSOCIATION C hris Davis Australian Water Associatio n (AW A) assumes no respo nsibility for opinions o r statements of fa cts expre sed by contributors or advertisers. Editorials do not necessarily represent o fficial A WA policy. Advertisem ents are included as an infor111atio n service to readers and arc reviewed before publication to ensure relevance to the water environ111ent and o bjecti ves of AW A. All material in Water is copyright and should not be reproduced wholly o r in part without the written p ennission of the Managing Edi tor.

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WASTEWATER 47

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BUSINESS SO

" WATER QUALITY RISK ASSESSMENT AND MANAGEMENT · IMPLEMENTATION EXPERIENCES Some hard-won experience in risk assessment M Chapman, PR Nadeba um, G Fi nlayson, S Carne

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WATER BUSINESS SPECIAL FEATURE: PIPES

Warer is sent to all AW A members eight times a year. It is also available via subscription.

" TREATMENT OF MUNICIPAL LANDFILL LEACHATE BY SBR Pilot plant trials teach a lot

73

INDEX 2002-2003

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OUR COVER: Chlorination and chloramination are still the major means for disirifection <if drinking water, b11t they have disadvantages. A ltho11gh ultra-violet radiation has 110 residuals, it is being applied in increasing volume. R ecently it has been f ormd that it is effective against the oocysts of Cryptosporidium which are resistant to normal doses of chlorine. WATER FEBRUARY 2004

1


FROM

THE

PRESIDENT

WATER EDUCATION - AT A WATERSHED Education is something people in the water industry tend to take for granted, but perhaps we need to pay more heed to it. If you look at the National Water Quality Management Strategy suite of documents, the COAG National Water Initiative and th e Framework for Management of Drinking Water Quality yo u will find reference to co mmunity in volvement and education in wate r manage m en t. Whilst commu nity education is acknowledged as an important part of water management, implementation of suitable programs wh ich can engage and inform the community about water issues is somewhat difficult. AW A has had an active interest in Rod Lehmann education for som e time , but has struggled to fi nd a meaningful, achievable role. A rece nt research proj ect has done wonders in sorting out what it all n1eans and how AWA migh t contrib ute. AWA's first real step forward ca me when Jenifer Simpson, with Qld Branch and the Sunshine Coast Environment Council , won a Natural H eritage Trust Fund grant to develop the We All Use Water su ite of ed ucation resources. T hat proved to be a real challenge and it was mainly Jenifer's huge personal commitment and tenacity that fi nally saw the product in print and on video.

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The We All Use W ater suite of educational resources includes a tool box of demonstration activities designed to help people understand water issues in a non- threaten ing way. An example of one of the activities involves building a model of a catchm ent in sand and working with the participants to identify ways catchment changes can impact o n wa ter quality. All activities are educational and can be done with som e fu n , making it an easy learning exp eriences. The We All Use Water resou rce kit also includes fact sheets, a manual, video and posters. Th ese have been availabl e for over a year. Wi t h su p p ort fr om the CRC for Catchment H ydrology, a training course was developed and six training courses have since been held for people who will use the We All Use Water resources kits. AW A has also been communicating with WaterWatch to see how our education in itiatives m ight link with th eir programs. W aterW atch has strong linkages with school curriculu1ns and we therefore hope to extend our education initiatives into schools as well. Whilst we have been working hard to develop an interest in community education , the response has only been moderate. We know that education is needed, but identifying what people actually want and who wants it, has been difficu lt. Our Board has recently reconfirm ed that education is an im portant part of our business and that it would like co consider investing significant (for us, at least) funds in an education project. Grappling w ith the nature and scope of the project wasn't easy, th ough, so the Board elected to have a prelim inary research project done to assess education ini tiatives and resources around Australia, and to find out what AW A's role should b e. W e now have a mu ch clearer idea, thanks to interview s and a survey carried out for us by Grahame Collier and Daniel D eere. They identified a strong demand for AW A to act as an independent facilitator and coordinator of national edu cation initiatives in vocational train in g, pro fessional edu cation and community education. Th ey did not uncover any burning need for us to be a basic provider in any of these areas as such, probably beca use respo ndents know as well as we do that the resources required to deliver in those areas are simply not available. As this issue goes to p ress, final to uches are b eing p ut to the first national water education conference in Canberra. I hope that some of the unknowns can be identified and some interest and enthusiasm generated in relation to water education and information programs. We hope that the outputs from the conference will enable us to set in place a business plan fo r our future activities and enable our current initiatives to be extended furt her. To achieve our goals of sustainable water m anagement we will need water managers to acknowledge the need for education, and work with us in developing suitable, collab orative programs and initiatives that will be effective in raising community knowledge about water. R od Lehmann

Next Issue Features the National Water Education Conference


DISINFECTION OF WATER

UV INACTIVATION OF MICROORGANISMS IN WATER - A REVIEW J L Clancy, T M Hargy Abstract

UV: a Physical Disinfectant

Though lo ng recognized as an effective disin fectant of many mi croorganism s, u ltravio let ligh t (UV) had tak en a seco ndary role in th is appl icatio n in th e drinking water industry, wh ere th e use of c hemica l disinfectants has b een fa vored . Re cent co ncerns o ve r the safety of c hemicals, th eir relative in effectiveness against Cryptosporidi11111, as well as th e h ealth effec ts of byproducts o f che mi cal disin fec tan ts, have cau sed trea tmen t pro fessio nals to look fo r othe r m eans of wate r disin fection. U ntil 1998, the issu e o f effi cacy for Cryptosporidi,1111 co ntrol seem ed co rule out the use of UV, as past research indicated the technology had Little effect . However, recent stud ies, using more e x ac t i n g me t hod o l o gi es to d ete rmin e oo cys t ina cti vati o n , have demonstrated th e p rofo und effect that this physical disinfectant has o n protozoan p a tho ge n s incl u din g C iardia and Cryptosporidi11r11. UV is now considered th e most effective disin fectant for control of C ryptosporidi1-1m in drinki ng water.

UV refers specificalJy to light in the 40400 11111 wavelength region. G erm..icidal UV is that portion in th e 200-300 nm range, and th e most effecti ve disinfec ting UV is that at 260 nm, wh ich corresponds to the peak absorptio n of DNA. As photons of UV are absorbed by DNA , photoproducts are fo rmed w hich in terrupt th e abil ity of th e DNA to repli cate, resultin g in death o f the microorgan ism and preventing infection o f a host animal by the mic roorga nism. The amount of UV itndiation reaching a surface is expressed as milli watts per squ are centime ter (111 W / c m 2) . Th e UV dose is a fun ction o f irradiation tim es exposure duratio n, or m Wsec/cm 2 . This is equi vale nt to millij o ul es per squ are centime ter (mJ /cm 2) . Wh ile UV was fi rst used in drinking water in France in 1910, and was first appli ed in th e U n ited States in 1916 (USEPA, 1996), it had not seen th e widespread drinki ng wate r appli catio n in the 20 th centu ry as it had in waste wate r treatme nt. So me ground water systems in th e U S have used UV fo r bacte rial and viral control in li eu of c hlorine , but with few exceptions, UV was not used in drink..ing water systems with surface water sou rces.

Introduction Protozoan cysts and o ocysts pose a sp ecial con cern to th e water trea tme nt ind ustry du e to the signifi cant adverse h ea lth e ffec t s o f Cia rdi a and C ryptosporidi11111 , t heir abili ty to pass throu gh conve ntio nal trea tme nt system s, and their resistance to che mical disinfectant s , a c h a r ac t e ri s ti c es p ec ia ll y pronoun ce d with C ryptospo ridi,1111 . Cryptosporidium parvum is a pathogen of concern in water supplies. This parasite causes cryptosporidiosis, a disease causing profuse , wate ry diarrhea , abdominal cramps, nausea, vomiting, and low- grade fe ver. In most w elJ nourished , immunocompetent individuals, infection may last betw een two and twelve days, and is usualJy self-limiting. H owever, in patients with congenital o r acquired immu n e defi c ien c ie s o r in malnouri s h e d individuals, infection can be considerabl y p ro l o n g e d , r es ulting in malabsorption, severe dehydration, and death . The n eed for re moval or inactivation of this and other drinking water pathogens, with minimal reliance on chemicals, has recently bro ught a new fo cus on UV and its effect on microorgamsm s.

Types of UV Lamps The m aj o ri ty o f com m e rcial UV sou rces are m erc my vapor lamps. Low p ress ure (LP) la mps prod u ce n early mo nochromatic light w ith a peak o utput at 254 m11, w hich vety closely corresponds t o the peak w avele ngth o f DNA absorption. Therefo re, these lamps are very germicidally effi cie nt. The output of a second type o f lamp , the m edium pressure (MP) m ercury lamp, is spread throughout the 200 to 300 n m range. While these are less effi cient, they are much m o re p owerful than LP lamps, so significant bactericidal effects can be

achieved with fewer units. A third ty pe of lamp chat produ ces UV is th e xenon based pulsed lamp. While a major portion o f pulsed lamp output is in wavel eng ths ocher than the bactericidal range, including visible (white) light, these also prod u ce re markable amo unts o f disin fectant UV .

Advantages and Disadvantages of UV One of th e maj or advantages of UV is th at no che micals are required to achie ve significant disinfection of microorganisrn s. This res ults in lo wered costs and redu ced hazards associated w ith storage of chem..i cal such as c hlorine gas. An added be nefi t is the elim..inatio n of disinfection by-produ cts (DBPs) , recognized as ca rcinoge ns over a lifetime exposure. Stu di es have shown th ere are no DBPs from th e use of UV in drinking water (Mall ey et al, 1996) . Ano the r ad van tage o f UV is t h e m inimal space requ ire ments o f a UV reactor. As UV lamp assemblies can b e built into p ipi ng configurations, a nd b eca use long residen ce-time co n t act c hambe rs are not necessary, structural fa cil ity requirem ents may be minimi zed . A significant disadvantage to UV is chat no residu al disinfectant remains follo wing tr ea tm e nt for di st ributi o n syste m protection. T his lack of residual also mak es dose m easurem ent diffi cult, and dose delive ty has to be 111easured usin g senso rs that may not adequately characterize dose thro ughou t the reactor. In Australi a, th e US , and othe r countries wh ere a distributio n sys te 111 residual is re qui re d, additi o nal c hlorin e-base d disinfecta n ts are still used. H owever, the concentrations can be reduced significantly and the issu es with DBPs 111i n imized .

UV's Effect on Microorganisms in Water The pro cess by w h ich th e absorptio n of U V by DNA causes inactivation involves the creation of photoproducts that

Table 1 . UV/Cryp tosporidium studies using in vitro surrogate methodology. Reference

Lamp type

UV dose (mJ/ cm 2 )

log10 inactivation

120 8700 180

>2

at, 1995

LP

Campbell et al, 1 995

LP

Clancy et al, 1 998

LP

Ransome et

2

<1

WATER FEBRUARY 2004

19


DISINFECTION

interfere with the microorganism's replicatio n. The sign ificant photoprodu cts in UV disinfection are thymine dimers. Th ese are created when certain bonds in the DNA strand are broken and new ones are formed, resulting in inhibition of replicat io n. W h e n mi cro o r ga ni sms a re incapable o f replication , they are also unable to infect a host organism. Different organisms exhibit differing sensitivities, so that o ne species exposed to a given dose of UV wi ll b e inacti vated by orders of m.agnitude more o r less than ano ther sp ec ies e xposed to the same dose . Generaliza tions can be made regarding the sensitivities of vario us types of o rganisms: Bacterial cells are quite vuln erable to UV; while most gen era are ina ctivated by as many as 4 log 10 w ith as little as 3 to 10 mj /cm 2 , particularly resistant sp ecies may require up to 34 mj/ cm 2 for that sam e inactivation . So m e bacteria, su ch as Bacilhrs subtilis, endure harsh conditions by p ro du cing e n vironm e ntally res istant spores. These bacteria] spores may be quite resilient to UV irradiation, requiring 60 rnj/crn 2 for 4 log 10 inactivation . Viruses exhibit significant resistance to UV disinfectio n, relative to bacterial cells. Many, such as poliovirus T ype 1 and Hepatitis T yp e A, will be inactivated by 4 log 1o with 7 to 30 mj/cm 2â&#x20AC;˘ Others, such as rotavirus strain WA and the coliphage MS2, require 50 to 80 mJ/cm 2 for 4 log 10 inactivation (Chan g et al, 1985, Wilson , et al, 1992). One of th e most UV resistant o rganisms o f public health concern to be identified is aden ovirus. Prese nt assay m eth ods ha ve sho wn adenovirus to require 120- 140 mJ/cm 2 for 4 Jog 10 inactivation (M eng and Gerba, 1996) . The efficacy of UV for the inactivation of Cryptosporidium had long been doubted b y the mi cr o bi o logic al and wa t e r treatm ent communities. This in large part has been fostered by the greater resistan ce o f Cryptosporidium oo cysts to ch emical disinfec tion w hen compared to other nucroorganism s. That notion had been strongly reinforced, however, by inadequacies of th e assays used to assess oocyst viability following UV treatment. Studies conducted in the mid to late 1990s using in vitro surrogate viability techniqu es indicated that relatively h igh UV doses were required for oo cyst inactivation as shown in Table 1. During this time p eriod , several researchers examined the actual infectivity o f oocysts follo wing UV irradiation , but only following the high UV doses shown in Table 2.

20

WATER FEBRUARY 2004

OF

WATER

Table 2 . UV /Cryptosporidium studies using infectivity methodology and high UV doses. Reference

Lamp type

UV dose (mJ/ cm 2 )

log10 inactivation

Dunn et al, 1995

pulsed

1000

>6

Clancy et al, 1998

LP

4380

>4

Finally, an exhaustive compariso n of the /11 vitro surrogate m ethods (DAPI/Pl staining, excystati o n) with the more definitive animal infectivity technique was carried o ut, and showed that the surrogate methods were n ot measu rin g oocyst in fec tivity, but were m easuring metabolic activity in dead oocysts (Bukhari et al, 1998). Oocysts tha t were dead (incapable of reprodu ction ) were still metabolically acti ve , and appeared to be " ali ve" when assayed using the surrogate methods. As a result, inactivation was significantly underestimated. A review of m ore recent bench scale studies using cell culture or animal infec ti vity to assay U V efficacy clearly d em o nstrates UV's ability to ac hi eve h i gh log in ac t i va t i o n of Cryptosporidiurn at low doses. These results indicate that the UV dose response of Cryptosporid/u((( oocysts is actually similar to that of bacterial cells; Cryptosporidiun, is the most UV susceptible pathogen of interest to the water industry studied to date. Giardia: While th e above studies w e r e primari l y c on ce rned with C ryptosporidium, two of th ese also examined the effect of UV on Giard/a. Finch and B elosevic (1 999) reported the response of Giard/a muris to UV to be similar to that o f Cryptosporidium. An evaluatio n of the dose response of Giard/a Iambi/a found this human pathogen to be quite vulnerable to UV, exhibiting greater than 4 lo g inacti vatio n at 2 mJ / cm 2 (Shin et al, 2000) .

Pilot Demonstration Studies of UV vs. Cryptosporidium With th e understanding chat appropriate m ethodologies could quantify th e signifi cant effect of UV on proto zoa, studies were designed to assess the ability

of UV to inactivate C ryptosporidiw11 m flowing pilot systems. A summary of these dem o nstration tests is provided in T abl e 4. These pil o t studi es were conducted on fi nish e d drinking w aters, with on e exception. In all cases , significant inactivation of Cryptosporidiu111 was achieved. The study by Hargy et al (2000) used rec reational water from a Florida water park, fol lowin g 3 days of heavy use. Oocysts w hich were added to this water and allow e d t o c ombin e with its constitu ents were still inactivated by greater than 4 log 10 by UV doses as low as 10 ni.j/cm 2 .

Conclusions Balancing th e need to provide effective microbial disinfection of drinking w ater w hil e diminis hing d e p end e n ce o n chemical disinfectants has been a difficult dilemma fo r the water treatment industty . Ultraviolet light had long been recognized as an effective disinfectant of bacteria and viruses, but not for protozoan pathogens. The prese nt understanding of UV's capab ili ti es against th ese ch emi cally resistant organism s opens the door for increased application of this technology in drinking water treatment processes. The USE PA (2003) now recognizes UV as a key elem ent in the tools available to utiliti es to increase protozoa disinfec tio n while decreasing the potential fo r chenucal byproduct formatio n. Hundreds o f fac ilities in the U S and Canada are upgrading th eir processes to include UV. This old technology has found a renew ed market in drinking wa ter.

The Authors Jennifer L. Clancy, Ph.D. and Thomas M . Hargy are with Cla ncy

Table 3. Recent UV/ Cryptosporidium studies using infectivity methodology and low UV doses Reference

Bukhari et al, 1998 Finch & Belosevic, 1999 Clancy et al, 2000 Clancy et al, 2000 Shin et al, 2001 Clancy et al, 2002

Lamp type

UV dose (mJ/ cm 2 )

pulsed

40

>3

MP MP LP LP LP

10

3.2

log10 inactivation

3

3 .4

3

3.0

3

<3

5

4.3


DISINFECTION

0 F

WATER

Table 4 . Flowing system evaluations of UV inactivation of Cryptosporidium us ing

infectivity to determine oocyst inactivation. Reference

Lamp type

System flow (gpm)

UV dose (mJ/ cm 2 )

log10 inactivation

Bukhari et al, 1999

MP

21 5

19

3.9

Hargy et al, 2000

MP

40

10

>4.4

Drescher et al, 2000

LP

4

120

>5.7

Mackey et al, 2002

LP

200

45

>4.7

Klevens et al, 2000

LP

75

50

>5.7

Klevens et al, 2000

MP

150

50

>5.7

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requirem ents into reality . Environmental Consultants, Inc ., P. O. Box 31 4, St. Albans, VT 05478 USA . Phone: (802) 527-2460 Fax: (802) 5243909, e mail: jclancy@ clancyenv.co m. J ennifer was called in as a consultant du ring Sydney Water's Cryptosporidit1111 crisis in 2000 (see Water J an 200 1).

References Bukhari, z., er al. 1998. P roceedings, A WW A Water Qua lity Technology C onfe rence, San Diego, CA. Bukhari, Z., et al. 1999 . M ediu m - pressure UV Light fo r O ocyst Inactivation. J. A111erica11 Wafer W orks A ssoc. 91 (3) :86-94. C ampbell, A.T., er al. 1995 . Inactivation of Oo cysts of Cryplosporidi11111 parr111111 b y Ultraviolet Irradiation. Wafer Res. 29 (11 ) 2583-2586. C hang, j.C. H. , et al. 1985. UV Inactivation of Pathogen ic and I ndicacor Microorganisms. Appl. a11d E11viro11. Microbiol. 49(6):136 1- 1365. C lancy, J. L. , et al. 1998. UV Light Inactivatio n of Cryptosporidi11111 Oocysts. J. A 111erica11 Water Works A ssoc. 90 (9) :92- 102. C lancy, J. L. I 999 . U ltraviolet Ligh t - A Solution co the Cryptosporidi11111 Threat? UV N ews 1 ( 1) :18-2 2 , Int e rn ati o nal UV Association C lancy, J.L., et al. 2000. Using UV to Inactivate C ryptosporidi11111. j. A 111erira11 Water Works A ssoc. 92 (9) :97- 104. C lancy, J.L. er al. 2002. Susceptibilit y of multiple strains of Cryprosporidi11111 parv11111 o ocysts to UV lig ht. D e nve r , C o lo .: AwwaR.F and AWWA. D resche r, A. er al. 2000. Cryprosporidi11111 Inactivation By Low Pressure UV In a Water Disinfection Device . Proceedings of the Small Drinking W ater and W astewater Systems Conference, Phoenix, AZ. D unn , J., et al. I 995. Pulsed Light Treatment of Food and Packaging. Food Tec/111ology, 49, 95. Finch , G.R., et al. 1997. Effect o f Vario us Disin fection M ethods o n th e Inactivation of Crypt os por idi 11111. A WW A R esea r c h Foundati on and Am erican W ate r Works Association. Finch, C.R. and M. Belosevic. 1999. Inactivation of Cryptosporidi11111 parv11111 and Ciardia 11111ris with M edium Pressure Ultravio let R adiation. Proceedings, U SEPA Wo rksho p on UV Disinfectio n of Drinking W ater, Arlington, VA.

Hargy, T.M ., et al. 2000. Shedding UV Light on the Cryptosporidi11111 T h reat. jo11mal of

E1111iro11111ental Healrlt, July/ August 2000 , ·1922. Kl even s, C. 200 1 . Param e ters for UV Disinfectio n of Surface W ater. Proceedings International UV Association Poster Session. Washington , DC. Ma c k e y , E. et al. 2 00 2. C o mparin g C ryptosporidi11111 and MS - 2 Bioassays: Im plications for UV Reactor Validation . J. American Water W orks A ssoc. (in press) . Malley,J. P. , et al. 1996 . .Evaluation of the ByPro ducts Pro duced by the Treatm ent o f Groundwaters with Ultravio let Radiatio n (U V) and Post Disinfecti on Follo wi ng Irradiation. D en ver, CO: A WWA and AWWAR F. M eng, Q.S. and C.P. Gerba. 1996. Comparative Inactivation ofEmeric Adenovirus, Poliovirus and Coliphages by Ultraviolet Irradiation. Wat. Res. Vo l.30 No. 11 pp. 2665-2668 Ran some, M . .E ., er al. ·1 993 . Effect of Di s infe c tant s o n th e Viabilit y o f Cryptosporidi11111 pa,1111111 O ocysts. vVmer S11pply, 11,75. Shin , G- A, et al. 200 ·1. Lo w Pressure UV Inactivation and Subsequent DNA R e pair Potential of Cryptosporidi11111 par1111111 O ocysrs. Appl. E11viro11. J\llirro. , 67:7:3029 . Shin , G- A., et al. 2000 Low Pressure UV Inacti vation of Cryptosporidi11111 par1J11111 and Ciardia lm11blia Based on lnfcctivity Assays and DNA repair ofUV- im1diated Cr)'ptosporidi11111 pa,1111111 Oocysts. Proceedings, AWWA Water Quality Techno logy Conference, Salt Lake C ity, UT. U S EPA. 1996. Ultraviolet Light Disinfectio n T echno logy In D rin king W ater Application - An O verview. Office of Water. , EPA 8 1 IR -96-002. U SEPA, 2003. Ultraviolet Light Guidance Manual, J une 2003 Draft. Pre pared by the Cadmus Group, Malco lm Pirnie, and Carollo Engineers. Wilson , B. R , et al. 1992. C o liphage MS-2 as a UV Wate r Disin fec ti o n Efficacy T est Surrogate fo r Bacterial and Viral Pathogens. Proce edin gs, A WW A Wa te r Qu ality T echnology Conference. T oronto, O ntario. 2 19-235.

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DISINFECTION

Im

OF

WATER

SELECTION OF A UV DISINFECTION SYSTEM FOR BUSSELTON WATER G L Bolton, J M Hooper Summary After tender analysis and a number of trials Busselton Water selected a m edium pressure UV system for disin fection of th e groundwater suppli ed to its customers.

Introduction Busselto n Water is an independent water authority that supplies water to domestic, commercial, light industrial, and special rural consu mers at Busselton and its environs in the Sou th West of Western Australia. Th e town's populatio n is approx. 25,000, however, this may grow du ring weekends and holiday periods to 65 ,000. Th e annual water consumption is curren tly about 3.6 GL with an annual growth rate of 8%. All th e water is produced fro m artesian bores to 300-800 111 depth, drawing on the Yarr ag ad ee and Leederville aquifers. T he water is slightly alkaline and is produ ced at temperatu res ranging from 26 to 38°C. The peak flow rate from eac h of the four plants operated by Busselton Water is currently about 225 Lisee. The Busselton Water supply differs fro m most of th e mu nicipal sources in Australia as the deep artesian aqu ifers offer high microb iological integrity and very low organic carbon loadings. Most other mun icipal water providers draw water fr om shallow production bores,

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22

WATER FEBRUARY 2004

UV Equipment Installation.

o pen water bodies, or a co mbination of sou rces that contain pa rticulate matter such as dispersive clays, plant material , and algal debris. Having been drawn from the bore, the water is aerated and filtered to remove iron befo re it is stored in tanks at its operating plants.

Requirement to Disinfect Drinking Water T he supply has historically been free of m icroorganisms and has therefore not been di sin fected . The A ustralian Drinking Water Guidelines (1996) as set by the National H ealth and Medical Research Cou ncil and Agricultural and Resource Management Co un cil o f Australia and New Zealand , recommend that all water supplies be disinfected to: • Effectively rem ove pathogens over a range of physical and chemical conditions; • Produce a disinfectant residu al which is stable and easily measured; • Produce no undesirable by-products; • Be easily generated, safe to handle, and suitable for w idesp read use; • Be cost effective .

Investigation of Available Disinfection Technologies Busselton Water commissioned its Groundwater Consultan ts, Rockwater Pty Ltd, to investigate th e various methods o f water disinfecti on, and make recommendations for a suitabl e system. T he objectives of the study were to determine a suitable disinfection system that effectively m eets the 1996 guidelines. T h e fiv e most co m mo nly-used d is in fect ion methods ie Chlorination, C hloramination, Chlorine Dioxide, Ozonation, and Ultra-Violet (UV) irradiati on, were investigated because they all offer good bactericidal activity. Chlori ne-derived m etho d s all provide a persistent residual effect, whereas UV irradiation and ozonation do not. UV irradiation produces no disinfection by-products, whereas all the other disinfection methods produce very low concentrations of potentia ll y harmful organic compou nds. Chlorine substances are all corrosive and plant op'e-r:ltors need to be trained in handling procedures.


DISINFECTION

Ozone h as a complex operating system that ca n present a danger to workers in the vicinity of the gas generating system. UV irradiation presents min imal risks to operators because all the en ergy is confined to a sealed container w ithout the generation of gases. Water su pplies can not be overdosed with UV irradiation whereas accidental overdosing of water sup p lies usin g chlorine substances and ozone may present a health hazard. All disin fec tion m ethods w ith th e exce ption of UV irradi ation are both temperature and p H dependent; i e the high er th e temperatu re and pH the less e ffic ie nt t h e di sinfe ction process. Bu sselto n water is warm and slightl y alkaline, and is therefore less suitab le fo r chlori n e d isi nfection th an many o th ers. Chlorine substances em it nunor tastes and odours that are freq uently objectionable to some consu mers. Ozone and UV do not affect taste or odour. Many water-supply authorities prefer to use chlorination fo r the disinfection

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of municipal water supplies because their retic ulation systems are exposed to open-a ir conditions after treatment (i.e. the water is pumped into sto rage tanks prior to distribution to the consumer). Resid ual disinfection is achi eved because ch lorine rema ins largely in the system . Ozone and UV methods must be used inline after storage as tanks can be contaminated by airborne bacteria or sma ll animals.

T yp ical comparative installation costs for the Busselton system were estimated to be 1.0 for chlorinati on and chlora mination disinfection systems; 2.2 for UV system s and 4.4 for chl orine dioxide syste ms. O perati o nal costs for UV systems are estimated to be typically 25 % of those for a chJorine system. R ockwater fo und that none of th e reviewed disinfectio n methods met all of the requirements and it was therefore

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23


DISINFECTION

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necessary to make some compromises to obtain the optinmm process for the Busselton reticulation system.

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UV Irradiation Selected As Best Available Technology Although none of the reviewed methods met all requirements, UV was selected as the most appropriate m eans of disinfecting th e Busselton water supply beca use it m et all of the design criteria except for maintaining a persistent residual barrier. H owever, as the water is maintained in a closed system following treatment, the chan ce of subseq uent contamination is smal l. Other factors considered during the selecti on were: The Austra li an Drinking Water Guidelines state that the implementation of a disinfection system shou ld be a consu ltative process involving the community. During a past survey, the residents of Busselton strongly objected to the proposed chlorination of the town water suppl y. At the Australian Water Association 18th Federal Convention held in Adelaide in April 1999, it was reported that municipal water authorities in other co untries such as the United States of America are steering away from chlorination because of th e concerns about disinfection by-products . In February 1997, Busselton Water resolved to adopt a policy of solely disinfect ing the water supply using UV irradiation. To achieve a confident level of destruction of all co mmon bacteria strains a minimum dose rate of 30 mWs/cm 2 has been specifi ed.

UV System Selection During 1997, a study tour of UV disinfection suppliers/manu fact urers within

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UV Disinfection Chamber showing UV Monitor and wiper mechanism.

Au s tralia and New Zealand was cond ucted to determine the most appropriate system for Busselton . T enders were called fo r the supply and installation of UV systems at fo ur ofBusselton W ater's treatment plants. Following a rigorous tender-analysis process, the co ntract to trial a UV disinfection system at Plant 2 in W est Busselton and to supp ly and install UV disinfection systems at three additional plants was awarded to Memtec Ltd. A multi-lamp low- pressure system. was tested over 12 months and a series of biomass destruction tests proved the system to be an effecti ve disinfec tant but it was found to be mechanically unreliable and did not provide the means to monitor UV dose . In 1998 M emtec was purchased by US Filter who recommended to Busselton Water that it test Hanovia m edium pressure system s. In 1999 two H anovia single lamp, m edium-pressure units were tested at Plant 2 for a twelve-month period. Biomass destruction tests undertaken

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WATER FEBRUARY 2004

UV System Performance Each of the medium pressure systems contains a single lamp housed within a protective quartz sleeve. A medium pressure lamp is known as a polychromatic lamp, as it produces UV from 200nm to 300nm. These lamps are specifically m anufa ctured by H anovia t o ha ve optimised spec tral outputs be tw ee n 240nm to 280nm. Th e most effective germicidal wavelength is 265nm, and the lamp is designed with this as the peak ou tput. Recent work undertaken in the USA has shown that UV light centered on 27 1nm to be th e most effective at de-

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using Bacillus subtilis (aged and fresh) and Escherichia coli across a variety of flow rates proved the medium-pressure units to be even more effec tive than th e lowpressure un its. Th e medium-pressure units are equipped with a UV monitor, variable power outputs that increase the UV ou tput wi th flow rate and an au tomatic quartz sleeve cleaning system.


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DISINFECTION

activating Cryptosporidium panmm , and UV light centered on 263nm to be the most effec tive at deactiva ting MS-2 coliphage. A low pressure lamp is known as a monochromatic lamp as it bas a single line output at 254nm. T ypically betwee n 8 to 12 low pressure lamps are required to replace the output fro m a single medium pressure lamp. UV light which is capable o f pen etrating through the water, th rough bo th th e outer cell m e mbra n e and th e nucl ear membrane wiJl fuse th e DNA. T he m echanism o f kill is th e ruptur e o f th e c ross b o n d s between th e two strands of DNA, or RNA in the case of virus. The UV dose, (Fluence) is determined by the combination of lan1p intensity, residen ce time (derived from th e fl uid velocity in the chamber) and the fluid transnuttance .

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The lamp intensity is measured by a dedicated monitor cam era positioned on the chamber waJJ . T he m onitor is inserted into the water, and is a sealed, calibrated device. No operator adjustment of th e monitor is possible, and the Hanovia mo nitor m easures the lamp output in absolute units o f UV intensity ; mW cm-2 (Fi gure

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Figure 4. Computational Fluid Dynamic (CFO) Model.

(m easured against double distille d water) is used in th is case . T h e re ceived UV dose is measured in mWs cm-2 (mJ cni.- 2 ) and is displayed o n the control panel. It is also availabl e fo r remote interrogation. The contro l system is capabl e o f data logging 4 variables, such as water flow, UV do se, int e n sit y, w ipe r frequen cy etc, and th is robust record allo ws any fault to be d a te and time stamped (Figure 5). Each UV system operates in duty/ standby mode. T he pow e r to each lamp is co ntinuously varied, to ensure that the specifie d UV dose is always deli vere d. Bo th systems may be operated at 50%, su ch that in the event of a failure a " bot" standby is immediately ava ilable. Th e operating protocols are strictly fai l-safe, and will not u nder any circumstan c e allo w untreated water forward . Th e control panel provides a broad range o f signals to actu ate valves, in itiate p umpin g and ge ne rall y pro vide m eanin g ful monitoring and control of the system. Th e units a ls o ha ve an automatic quartz sleeve cleaning system, o r wiper. T his is operated on a timed basis, and uses lin1.it switches to position th e wip e r mechanism away from a burn ing lamp. UV is extremely destructiv e to the wiper mec hanism and rapid failure woul d res ult fro m prolo nged exposure.

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Busselton W ater Board has co mmissioned two Hanovia u nit< at each of its four plants. Hano via 's distributor, Flu idquip Australia, supplied the m edi um pressure uni ts, spare parts and after-sales se rvi ce.

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H anovia uses detailed C FD Figure m o deling techniques to establish the actual distribution of residence time within the chamber, an d hence th e flow rate is used to provide the sec ond inp ut to the dose algorithm (Figure 4) . T he third input to the dose algorithm may be provided from the on-line trans-

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mittance monitor (a p atented device that m easures th e transmittance o f th e flu id) although th is inpu t may be assumed to b e constant if the flui d is from a high quality stable source. T his is the case at Busselto n and therefo re a faccor 90%

Busselton W ater Board plans to install additional UV disin fection systems at new treatment plants as they come o n lin e.

The Authors George Bolton is th e P rin cipal Groundwater Profess ional for Rockwater Pty Ltd. John Hooper is the Managing Directo r o f Fluidquip Australia Pty Ltd. E ma il: j o h n@fluidqu ip.com.au. WATER FEBRUARY 2004

25


DISINFECTION OF WATER

ENVIRONMENTAL AND WATER TREATMENT PROCESSES THAT CONTRIBUTE TO MICROBIAL DESTRUCTION - HIDDEN SOURCES OF DISINFECTION A R Keegan, P T Monis, D Daminato, P Cox, H Bustamante, C P Saint Abstract This paper provides the background and preliminary results fo r two recen tly established C RC for Water Quality and Treatment projects that are investigating the survival of pathogens in source waters and through the wa ter treatment process. Cryptosporid/11111 parvum and im.porcant groups of enteric viruses are being used in the studies that w ill deal w ith identi fying biological, chemical and physical processes that form non-obvio us or "hidden" types of disinfection in addition to the known applied forms. Such studies have recently becom e possible due co advances in detecti on methodologies. H ere there is heavy reliance on procedures that employ cell culture and quantitative polymerase chain reaction (Q - PCR) co dem o nstrate retention o f pathogen infectivity, a key public health criterion. This is critica l because the previous methods chat were routinely employed overestimated pathogen survival. It may well be that by careful management of water reso urces and sm art engineerin g of treatm ent processes pathogen destruction can be optimised leading to operational savings.

Introduction In the water industry disinfection is usually equated w ith the operational act of utilising a chemical or physical process to destroy pathogenic mi cro-organism s, distinctly separati ng this from processes of removal. Disinfection studies usually examine the effec t of disin fectants, either alone o r in combinatio n, o n microorganism s that are relatively easily grown in the laboratory. H owever, in practice raw water is often created through a series of chemical and p h ysical processes resulting in substantial removal of microorganisms and also providing a potential for additional levels of microbial inactivation. Some treatments may predispose organism s to inactivation in subsequent p rocesses although chis has not been previously investigated. In addition, better methods have been developed for assessing the effect of disinfectant processes on key

26

WATER FEBRUARY 2004

Figure 1. Cryptosporidium parvum oocysts labelled with a fluorescent monoclonal antibody.

pathogens w hich are resistant to conventional, widely used disinfectants such as chlorine. Whilst ultra violet (UV) light has becom e increasingly p opular to destroy mi cro - o rganisms in water treatment (N atio nal Water R esearch Institute/ A wwaRF 2000) th ere has been no straightforward way to quantify its direct effect on the viability of key water born e pathogens such as Cryptosporidium, Giard/a and certain groups of viruses. In recent time s, m ethodolo gies have become available that can clearly measure the abili ty of such pathogens co reproduce and cause infection following exposure to UV light (Rochelle et al., 2002), the true m easure of their significance to the water industry in a public health context. In the case of Cryptosporidium, we now know that the traditional methuds used previously to assess survival were ve1y conservative , so it is timely then to ask the question: are there processes occurring in reservoirs and water treatment facilities that provide so m e m eas ure of "disinfec ti on" or increased susceptibility to disinfection previously not recognised? These processes could be biological (e.g. predation or degradation) in raw waters, chemical, (e.g.

pH , c hemi cal coagulants , ch lorin e, chloramines) or physical (e.g. temperature, dissolved air flotation) during water treatment operations. Various combinations of these processes will be acting on micro-organisms as they pass from the catchment, through th e water treatment process and into the supply. If we can establish what effects these types of "hidden" disinfectants have on key micro-organisms with certainty then there could be key operational savings to be m ade. For instance the stress of these typ es of potential pre-disinfection (or agen ts that "sensitise" micro-organisms during treatment) may result in the target micro-organism being more readily destroyed by conventional disinfection, leading to reductions in Ct values and chemical doses; providing reasonable aesthetic quality (colour, turbidity) could be m aintained. A reduction in chemical dosing would d ecrease th e risk of formatio n of unwanted by-products and be highly acceptable to the public. Conversely for th ose operato rs controlling unfiltered water suppli es chat m erely undergo traditional disinfection the outcomes of these proj ects will reveal the


DISINFECTION

sign ificance (if any) o f the abse nce o f wate r treatment processes pri or co disinfe ctio n and w ill also yield important inform ation on the physical and biological condition s in the catc hm ents chat are likely co affo rd additional protectio n. Processes such as chem ica l coagulatio n are known to pro vide very effecti ve physical rem oval of m icro-organisms. In th is case rem oval wo uld "cl eanse" the wate r supply but there are po te ntial concerns rega rding contam inati on o f the en viron me nt that rece ives th e resul ting sludge, particu larly if m ic ro organ ism s retain viability. Risk assessment and hazard analysis and critical control point (H ACCP) principles are now being rigorously appl ied to water suppli es. Additional information on the likely survival o f key microb ia l contam inants in a wate r so urce o r through the trea tm ent process will provide important data co develop and support such models. Acc urate risk assessm ent of the entire w ate r supply chat includes data on the vi ab ility and infec tivicy of key resistant pathogens such as Cryplosporidi,.1111 ca n also be used fo r be tter in fo rmed respo nses to breakthroughs at critica l control poin ts .

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J ust over a year ago two large projec ts com m enced , suppo rted by the C R C fo r Wa te r Q uality a nd T rea tm e nt a nd W SAA , that seek to : • establish w hethe r th ese " non-obvious" so urces o f di sin fectio n are op erative both in reservo irs and th rough wate r treatme nt processes; and • understand th e significa nce o f th ese m ec hanisms o n the production of high qua lity d rinki ng and re-use water.

T h e two proj ec ts a re e nti t l ed " [n ves t iga t io n o f t h e Sur v iva l of Cryptosporidii1111 in Environmental Wate rs" and "Optimising the Water Treatment and D isinfectio n Trai n for P ath og e n D estructio n ". T his paper summ arises the aims a nd obj ectives o f the two C R C proj ects and d etail s t h e 111.e t h o d o log i es b e i n g em ployed. Some early results are also d iscussed and considered with regard to future in vestigatio ns.

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DISINFECTION

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A Choice of Pathogens 0

Cryptosporidium

The c urrent Framework for the managem ent of drinking water quality in Australia (NHMRC/ ARMCANZ, 2001) is based on H ACCP principles. A key component of the framework involves the identification and risk assessment of hazards across the w hole water supply system i.e. from the catchment to the tap. As exemplified in section 2.3, page 14 of the Framework, Cryptosporidium is recognised as a hazard to water quality and a poten tial threat to public health. This threat has been realised in th e form of waterborne outbreaks of cryptosporidiosis in the USA, Canada and the UK that have been associated with contaminated public water supplies. The most notable being in Milwaukee , USA (1994) by consumption of publicly supplied water contaminated with Cryptosporidiurn. Ciyptosporidium paivun, and closely related species can cause gastroenteritis that can be life threatening to the immunocompromised, and therefore pose a hazard to water quality. The environmental form of this organism, which is an oocyst, is highly resistant to chlorine, the standard m ethod of disinfection used in water treatment plants and distribution systems. C urrently , the information necessary for a risk assessmen t of Cryptosporidium, suc h as the fa te and transport of oocysts through catchments and reservoirs, the infectivity of oocysts in reservoi rs, the inactivation of oocysts across the treatment train or the length of time that oocysts remain infecti ve across water supply systems, is not available. HistoricaUy, the estimation of oocyst in fectiv ity or viability has been difficult due to limitations of the test m ethods available and the low oocyst recoveries from environmental samples. Vital dye staining of oocysts followed by microscopic analysis has previously been used routinely bu t it is now known to overesti mate viability w hen compared co mouse infectivity. Recently the A WQC has established an assay combining ceU culture with a quantitative test for detecting C ryptosporidi1m1 DNA (the polymerase chain reaction) for estimatin g the infectivity of Cryptosporidiun, oocysts (Keegan et al 2003). This technology is now being put in place in Sydney Water's laboratory. Other groups have recently demonstrated that this m ethod is equiva lent to mouse infectivity (e.g. Rochelle et al., 2002). There have only been two studies that have examined the survival or aging of oocysts in environmental waters and these

28

WATER FEBRUARY 2004

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studies used either vital dye staining (Robertson et al., 1992) or in vitro excystation (Chauret et al., 1998) as indicators of oocyst viability. Such methods are known to be conservative measures of viability and provide over- estimates compared with animal infectivity assessm ents. A limited study (Ugu en et al., 1997) has examined oocyst survival using excystation and a crude cell culture infectivity assay. H owever, this was only done using reagent water (with or without oxidants or fi xatives) at a single temperature (4°C) and the cell culture assay was not quantitati ve.

Viruses Over 150 types of enteri c viruses may be present in raw sewage, depending on th e viruses circulating in the community. The water borne virus pathogens include enteroviruses, adenoviruses, rotaviruses, hepatitis viruses (typ es A & E) and human caliciviruses (noroviruses). Although many enteric virus infections are asymptomatic, som e cause gastroenteritis, hepatitis, respiratory infections, eye infections, meningitis, carditis, muscular disease and rashes. Tn many cases, infected individuals excrete enteric viruses in high numbers. While noroviruses (formerly Norwalk and r e lat ed v iru ses), toget h er with parvoviruses, may ca use up to 60% of all h uman gastroenteritis cases (W HO sentinel program report), little is known of virus distribution in the environment, particularly in water supplies, or of the effects of water treatment processes on these viruses. Certainly, rotaviruses, wh ich cause severe vomi tin g and diarrhoea in children less than two years old, have been shown to survive conventional coagu lati on-based treatme nt processes used for drinking water, even when the chl orine residual and ba cterial indicators are at acceptable levels (e.g. Keswick et al., 1984). Water-related

o utbreaks of gastrointestinal disease have been associated with rotavirus co ntamination of seafood and water used to spray crops (e.g. Rose et al., 1986). Enteric adenoviruses are also significant human pathogens, ca u sing co njun ctivitis, gastroenteritis and respiratory disease. The genus Enterovirus belongs co the fam ily Picor11a11iridae (i.e. small RNA viruses) . The latest classification lists six human species including polio11irus, the type species, and hu man enteroviruses A to E, and three animal species (International Committee on Virus Taxonomy, 2002; see http:/ /www.ncbi.nlm. nih.gov/ lC T Vdb/ lctv /index. htm). Enterovirus in fections can affect a range of organ systems, causing neurological (poliomyelitis, aseptic men.ingitis, encephalitis), respira tory (common cold, tonsillitis, pharyngitis, rhinitis), or cardiovascular (myocarditis, pericarditis) diseases. A number of studies in the 1980s reported the detection of enteroviruses in treated water (e.g. K eswick et al., 1984). Reoviruses, related to the rotaviruses , are carried by a wide range of mammals and while they are not known to be associated with disease in humans, they have been suggested as a useful indicator of faecal pollution of waters. Investigation of the occurrence and persistence of many types of hun1an enteric viruses in environmental samples such as water is increasing as human health and product safety concerns become more focussed. Contamination of receiving waters with human enteric viruses can occur from sewage treatment plants, smaU on-site sewage treatmen t units or stormwater. The presence of viruses in receiving waters may not be correlated with the presence of indicator bacteria (Ashbolt et al., 1993) since viruses are more persistent in the environment. While there is no epidemiological evidence that waterborne virus trans-


DISINFECTION

mi ss ion is occ urring w he re mode rn water treatment proc esses are in pl ace in Australia, so me recent surveys have shown that viruses ca n still be de tected in the drinking water of large citi es. For exa m ple, human adenoviruses we re shown to be present in ] 3% of raw water and 9% o f treated water sampl es in Sout h Africa (Van H eerden e1 al., 2003). At present it is uncertain whether th e cu rrent protection offered by o ur water trea tment processes, as evidenced by the epide miological data , is provided by highly efficient removal of potentia lly harmfu l viru ses or by a co m binatio n of rem ova l and disinfection. In addition, the data on the prevalence of human e nte ric viruses in Au stralian wa te r systems and indeed th eir re moval across treatm e n t trai ns is defic ie nt because methods fo r the isolation, detectio n and id e ntifi cat ion of t he se potential path oge ns is technica ll y c hallenging, tim e consuming and cos tly. C ultivable water- borne viru ses are trad iti o nall y detected by i11 vitro ce ll cu lcure with the obse rva tion o f the cytopathic effect (da ma ge to cell s) ta ki ng approxi mately a mo nth for confirmation. M any viruses cann ot be culcured (such as noroviruses) and require al te rnative m ethods fo r iden tification such as the polym erase c hain reaction (PC R.). Th is preve nts dete rmination o f t h e viru s pote ntial infectivity, as PCR wi ll detect in fe ctious and no n-i nfectious vi ru s parti cles.

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Inactivation of C.parvum after coagulation/floculation processes with alum

C 0

0.8

¡.;::;

0.6

.fl

0.4

cu

0.2

cu > C

Cl

0

-,---

.2 -0.2

75

100

200

-0.4 Alum dose (mg/ L)

Figure 4. lnfectivity of C. parvum oocysts after exposure to alum/flocculation process. The infection was assessed using the CC-PCR assay.

T he ce!J culture process is able to support the growth of both C. ho111i11is (prev ious ly known as the type I or h u man genotype of C. panmlff) and C. parv11111 (type II o r ca ttle genotype), th e two spec ies of Cryptosporidi11111 responsible for the maj o rity of hum an infections. In addition to the ce!J culture assay, flu orescence microscopy has been used in the pre paration of the oocyst seeds for use in experim en ts (Figure 1). All experime nts were con ducted to all ow fo r the detection of 3-logl 0 inactivati o n. T he cell c ultu re and quantitative PCR fa cil ities are now available at the AWQC and

Sydney Water laboratories. A stre ngth of th is C R C WQT project coll aboratio n is that fi ndings based o n these new m eth ods ca n be co-va lidated in both labo ratories.

Viruses Co nv en tional water t r eatm e nt processes rem ove substa ntial numbers of viruses (e.g. McTigue et al., 1998). The refore , ve ry small numbers shoul d pote ntiall y be found in treated water. PC R assays that all ow detection of low levels of viruses have been developed but are often han1pered by the presence of

Tracking Pathogen Survival Cryptosporidium

T he pri mary m ethod used to assess oocyst infecti vity in th ese proj ects is the cell culture i nfectivity assay. This assay is based on a method developed at Murdoch University, with the exception th at a m o lecul a r tec hni que (P C R ) i s u se d i nstead of microscopy to qu an tify the level o f in fect ion (Ke ega n el al., 2003). Th ese m eth ods have been successfully used in combi nat i o n to exa mine the effectiveness of various disinfection methods agai nst live oocysts as part ofCR C WQ&T project 3.1.4 "Novel methods of pathogen destruction" (K eegan et al., 2003). T he qu antitative PCR assay has a se nsitivity leve l of a single oocyst and the cell c ulture infe ctivi ty assay coupled w i th qu antitative P CR can detect 1 - 10 infectious oocysts.

Contact Acromet for further information: Acromet (Aust) Pty Ltd. Melbourne Ph:(03) 9544 7333 Fax:(03) 9543 6706 Sydney Ph:(02) 9682 t 488 Fax:(02) 9682 4580 Perth Ph:(08) 9524 7931 Fax:(08) 9524 7932 E-mail:chemex@acromet.com.au Distributors Nationally.

WATER FEBRUARY 2004

29


DISINFECTION

inhibitors su ch as humic acids. Such problems can be overcome by the use of cell cultu re. Many enteric adenoviruses, reo viruses and enteroviruses can be simply cultured ii, virro. The comm o nly used cell lines are of human and R hesus m o nkey origin (e.g. LLC-MK2, HEp-2, MR C-5). As th is m ethod involves growing the viruses for a period of tim e, it detects viable viruses in a way that has been accepted fo r over fifty years. Many of th e enteric viruses are identified by the charac teristic cytopathic effect (C PE) that they produ ce o n th e specific cell lin es used. H owever, depending on the virus, the cell line used, and th e length of exposure in th e environment it may take at least a month to be able to reliably report a negative cell culture test. By coupling rea l- time PC R to cell culture, it is possible to d etect and qu antitate viral infection of the cell line before a CPE is detectabl e. T his modification will also allow the detection of viruses that cause little or no CPE in the cell lines. Methods are currently being developed by the research partners to allow 1nore rapid detection and quantitation o f the virus infection of the cell culture as well as confirmation of virus type by using cell culture coupled to Real-time-quantitative PCR (Q-PCR) . D etecti on o f either non- cultivable viruses (e .g. noroviruses) or non-C PE causing viruses (eg hepatitis A virus and rotavirus) has histo rically been by direct PC R. As noroviruses are nonculti vabl e, the PC R result indicates prese nce of the virus but not viability. In the case of the non-CPE causing viruses, the development of CC-PCR will allow the detection of these viruses with the possibility of determining viability.

PRECISE MEASUREMENT FOR TOTAL CONTROL

Depolox 3 plus - conrinuous measuremcm of free or row.I (combined) chlorine, pH o r flu oride in drinking water applicacions. MFA (Multi Function Analysers) range - measuremenr and conrrol, from simple measurement rhrough ro dem;tnding closed loop processes, fo r a varicry of applications. Micro 2000 Residual C ell - conr inuous, o n-line measuremcnr of free or coral chlorine, chlorine dioxide or porassium perm anganate

residuals. Ideal for all types of process water, includi ng sea water.

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What are we doing? Survival of Cryptosporidium in environmental waters

Improving our understanding of th e fa te of Cryptosporir/i11111 oocysts in the en vironment was identifi ed as a priority during proj ec t pl an ning workshops held at the start of the C R.C fo r W ate r Quality and Treatment M ark II. A proj ect to investi gate the inactivation rates of Cryptosporir/i11111 oocysts in enviro nm ental wa ters using a q uantitative Cryptosporir/i11111 cell cultu re infectivity assay, jointly fund ed by the C R C W Q &T and WSAA, commenced du ring the last quarter of 2002. T he in fo rmation fro m this project can be used in combinatio n w ith hyd rodynamic mo dels to provide better estimates of th e ri sk o f infectious oo cysts reaching th e off- takes of reservoirs. This is criti cal for th e risk assessment of Cryprosporir/i11111 in source water and will determin e the effectiveness of residence in reservoirs as a barrier. Laboratory-sca le experiments are being condu cted to determine the effects of temperature on th e long-term survival of fresh o o cysts of Cryptosporidi11111 parvum (cattle or type II geno type) in reagent and environmental waters of different quality and biological activity. Ini tially, bench scale experiments have been used to determin e the effec t of basic parameters such as tem pera tu re (e.g. 4°C, 15°C, 25°C), biological activity and o o cyst concentration on fresh CryptosporirfiH111oocysts. Oocysts suspended in reagent grade water were used to optimise th e sampling and analysis methods and generate baseline data for th e inac tivation rates. Following th is various raw waters have been supplemen ted with Cryptosporir/i11111 and tested for inactivation rates. The chemical and mi crobiological quality o f all samples was determined using standard 111.ethods. E xpansion of the sampling sites has been proposed and w ill include sites from South Australia, N ew South W ales, Vi ctoria and Queensland. In order to differentiate between the effects of microbial activity or physical factors, oocyst infectivity will be assessed in parall el for uncreated and treated (0 .2 ~1111 filter sterilised or pasteurised, depending on sample turbidity) water samples. T he oocysts arc monitored for up to 16 weeks. Even if the oocysts are no lo nger infecti o us, continued direct monitoring (i. e. examination by microscopy rath er than infectivity assessment) will provide information on how long oocysts persist and how aging affects the morphology o f oocysts in environmental waters. T his informatio n is of direct relevance to the water industry because standard m icroscopy-based techniques use m orphological criteria for the identification o f Cryptosporidium in routine samples. For these experiments, fresh C. panmm (cattle or type II genotype) oocysts w ill be used. This will dem onstrate that the assay can be used to assess th e infectivity o f oocysts in water and allow the determination o f inactivation rates under specific conditio ns.

Optimising the water treatment and disinfection train for pathogen destruction M any studies have examined the removal of Cryptosporir/ium oocysts and viruses by water treatment processes (e.g. Plummer et al. , 1995: M cTigue et al. , 1998) but none have looked at the effect of such processes on their infectivity. Similarly, many studies (e .g. Keegan et al., 2003) have assessed disinfection metho ds for oocysts and viruses, but such studies have been done in isolation from the rest of the water treatment train. D ep ending on the efficiency of treatment, the organisms may pass through the water treatment process in conventional w ater treatment plants and reach the distribution system. Oocysts are also highly resistant to chlorination. The cru cial points, however, are:


DISINFECTION

â&#x20AC;˘ to establish w heth er the oocysts that have been in a rese rvoir for differe nt le ngths o f time and reach th e wate r treatm ent plants are viable and infectious; and â&#x20AC;˘ to establish w hether the oocys ts that may brea kth rough water trea tm ent plants are in fec ti ve o r viabl e. Laboratory scal e experiments Uar tests) are being used to determin e the effects of conventi onal and DAF (D issolved Ai r Flotatio n) wa ter treatm ent processes on pathoge n survival and infecti vity . R aw wate r s s pi k ed w ith p a th oge n s (Cryptosporidi11111 or water bo rne enteric viruses) are treated with eithe r alum or fe rri c chloride as coagulants and polyelectrolytes such as Magnaflo c L T 35 and filtration aid flocculant (Magnafloc LT 20) . The concentrations o f coagulants used (alum or fe rric chloride) are se lected to m eet two main co nditions. Sub-opti mum c on centra ti o n s of c o ag ulants (and polye lectrolytes) are used to partially rem ove o o cysts and viruses in order to leave su fficie nt oocysts free in the treated water. Th ese free mi crobes are th en exan1ined to determ ine th e effect o f coagulants on the viability and infectivity of coagulan t-treated o rganisms. With th e use o f optimum coagulant conditions maxim um re mo va l o f o ocysts and viruses in th e flo es is attained. T his pro cedu re enabl es th e determinatio n o f th e viability and infecti vity o f the organ isms trapped in flo es. Experime nts wiU be carried o ut in reagent grade and e n viron m ental waters of differe nt qual ity . Th e effects of the diffe rent treatment regimes are bein g assessed to allo w the identifi cation o f c ritical fac tor(s) th at aid in pathogen destru ction or inacti vation th rough the water trea tme nt process with uniqu e wa ter types. Th e data will be appli ed to stage 2 of the proj ect fo r loo king at combin ed trea tment and disin fe ction and will be used as a baselin e for inactivation due to the treatment train. Experime nts will be perfo rmed to determin e accura te C t data for a range of d i sin fe c t a n ts in c l udin g c h lo r in e, chloramin e, ozo ne and ultraviolet ligh t (UV) for both Cryptosporidi11111 par1111111and enteroviruses. T h ese da ta will be critical fo r determining th e effects o f combin ed w ater treatment and disin fec tion assays . Altho ugh a great deal of inactivatio n data exists fo r th ese disinfection methods it is necessary to repeat the work to gain accurate baseli ne data fo r each disinfectant. T his will then be compared directly to the data generated in the combin ed experi ments. Th is may aid in redu cing the disinfectant dose requi red for effective

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in activation o f th e orga nisms. D ata w ill b e exa mined to model the destructi on of both e nte roviruses and Cryptosporidh1111 in raw wate r sa mples and determin e th e fac tors that aid inac ti va tion. Stage 2 objec tives are to combine th e water treatme nt pro cesses w ith the disinfection strategies Ested above. O ocysts and virus particles will be run through the water treatme nt ste ps and fin ally exposed to disinfectants. I nfecti vity of pathogens will be determined using cell c ulture assays. Du e to th e stresses encountered in the water trea tm ent process, it is anticipated that aged oocysts will be m o re susceptible to disinfec tio n at th is stage . Data can be directly co mpared to that generated in stage 1 co determin e th e changes in susce ptibi lity to disinfec tio n afte r th e water trea tm e nt process. Pilot studies will be perfo rmed to assess inacti va ti o n rates of Cryptosporidi11111 and enteroviruses using large-scale faciliti es . T he pi lot plant at AWQC opera tes at 600111l / m inu te (3 6L/ hr) and mimi cs th e process encounte red in a water trea tme nt plant includin g contact and passage times. The pil o t plant co nsists o f a rapid mi xer

fo r coagulation foll owed by mixers to aid in flo cculation. W ater is se nt throu gh a sedim e ntatio n step and fin ally passed throug h a gra n ular activated carbo n (GAC) fil ter m atrix. Pathogen samples can be tested in raw water, product water, and sludge fro m sedim entatio n and filte r backw ash wa ter. Ra w water will b e sourced from treatment fac ilities and dosed w ith pathogens. Th e plan t operates o n a 200L vo lume fo r each run. T he effects of differe nt water treatme nt system s on environmental Cryptosporidi11111 and virus in fectivity reco vered from the waste streams of water treatment facilities will be exami ned. Raw water, sludge a nd filte r backwash wate r sam ples w ill b e collected from water treatment plants and waste water plants fo r assessm ent of pathogen loads an d viability. The pla nts selected will operate with diffe re nt wat e r qualities and treatment processes and allow direct co mparison of th e effects of the trea tme nt processes and water quality . Spec iatio n of isolated Cryptosporidi11111 w ill be pe rfo rmed to determi ne th e so urce o f oocysts con tamin atin g the treatm e n t systems and viral identifica tio n w ilJ b e

ENVIRONMENTAi ENGINEER/HG

State of the Art containment systems

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DISINFECTION

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performed. A virus-monitoring program wil l be set up in SA for the first year to determine the viral load in SA reservo irs and water treatment plants, as this is currently unknown . C urrently there is no understanding of the viabi li ty or infectivity of oocysts and viruses in the waste stream. One of the major concerns w ith waste disposal and recycling is the increased likelihood of human co ntact w ith pathogens and increased health risks. In addition, during the backwash of filters oocysts can be released and returned to the head of the plant to pass through the process aga in . This study wi ll also investigate altern ative processes such as DAFF (Disso lved Air Flotation and Filtration) to treat backwash waters and determine th e most efficient and cost effecti ve m ethods of removing and and/or inactivating C ryptosporidi11111 oocysts and viruses for particular water types.

cu lture PCR assay. Subsequent experiments exposing oocysts to a complete jar test (including coagulation and flocculation and sedimentation) demonstrated minimal inactivation (-0.4 log 10) of Cryptosporidi11111 at high alum doses (up to 200 mg/L) (Figure 4). Paral lel work with fe rric ch lorid e at Sydney Water also dem onstrated minimal ina ctivation of oocysts after coagulation with ferric chloride with doses up to 15 m g/ L. In these studies the oocysts contained within floes were analysed. Th is is because FeCl3 concentrations above 10 mg/L removed the large majority of th e oocysts fro m the water column . As a by-product of water treatm ent processes, slu dge is a co nc entrated fo rm o f th e undesired contaminants present in raw water and may be an important source o f pathogens . l n South Australia sludge can be disposed ofby landfill or by sending to wastewater treatment plants.

What have we found?

Future Work

Prel iminary results have indicated that o ocyst survival in water is strongly affected by temperature . Cryptosporidi11111 su rvival was assessed over 26 m onths and indicated that viable oocysts were present for up to 15 months when stored at 4°C (Figure 2). Oocys t infe ctiv it y was measured during the in cubation period and it decreased at a slower than antic ipated rate fo r the first 0-8 months, although it d eclined rapidly after 9 months. Experiments have demo nstrated that oocysts in reagent water or sterile raw water, w hen incubated at either 4°C or 15°C, main tain their infectivity fo r m ore than 18 weeks. Oocysts incubated at 20°C and 25°C show a decrease in infection over time, w ith higher temperatu re ca using faster inactivation (Figure 3). Another effect observed in raw waters has been a decrease in the number of oocysts present in samples over time. T his decrease ha s bee n attributed to th e presence of organisms capab le of feeding on Cryptosporidi11111 and like-sized particles in the water column. At tempera tures of 20°C and above the loss of oocysts can be dramatic, occ urring withi n weeks. Examination of reservoir waters for the presence of C ryptosporidi11111 predators has demonstrated the presence of amoebae, rotifers and ciliates that may perform this funct ion. Further investigation will determine the rates of predation and identify th e likely predators. Exposur e of C ryptosporidium to aluminium or ferri c- based coagulants demonstrated minimal inactivatio n at set doses in reagent grade water using the cell

Laboratory scale studi es w ill be completed to determ ine th e survival of Cryptosporidir1111 in raw waters. T his w ill be fo llowed by the establishment of tank tests performed outdoors to determine the effects of sunlight and turbidity on oocyst survival. An H onours project is schedu led for 2004 at A WQC to isolate and identify C ryptosporidi11111 predato rs in raw waters and sed ime n t sa mples. Cu ltures o f amoebae, rotifers and ciliates will be utilised in feeding studies to determine feeding rates. Water treatm ent processes wil1 be applied to viruses to determine the effects of alum and ferric chloride on virus infeccivity in cell culture and determine the rem oval rates. This w ill also include m odelling the DAF process and determine the survival of C,},ptosporidiwn and viruses in treated wastewater.

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Acknowledgements We thank the CRC for Water Quality and Treatm ent and the Water Services Association of Australian fo r supporting these projects .

The Authors Dr Alexandra Keegan is a R esearch Microbiologist at AWQC and project leader of C R C WQT project 2.4.0.4. Dr Paul Monis is the Senior Research Mi crobiologist at AWQC and proj ect leader of CRCWQT project 2.2.0.2. David Daminato is a R esearch Officer at the A WQC. Dr Peter Cox is the Project Director of the Biological Sciences

Labo rato ries at Sydney Water. Dr Heriberto Bustamante is the Principal Consul tant in th e Asset Management Division at Sydney Water. Dr Chris Saint is the R esearch and Development Manager at the Australia n Water Quality Centre and project leader fo r CR CWQT project 2.3.0.4. Email alex.keegan@ sawater. com .au. Ph: (08) 8259 03·12.

References Ashbolt, N ., et 11/., (1993) Pathogens in the assessment of polluted receiving waters of Sydney, Australia . WatC'r Sci. Tec/1110/. 27(34):449-453. C hauret, C., et al. , Aging of Cryp1osporidi11111 p111v11111 oocysts in river water and their susceptibility to disinfection by chlorine and monochlo ramine . C1111 J Miffobiol, 1998. 44(12) : p. 1154-60 . Keegan, A.R., Fanok, S ., Monis, P.T., and Saint, C.P. (2003) Cell culwre-Taqman PC R assay for the evaluation of Cryp1osporidit1111 part111111 disinfection . Appl. E11uiro11 . MiCl'obiol. 69(5): 2505-2511. Keswick, B.H., Gerba, C.P., D uPont, H.L. and Rose, J.B. (1984) . Detection of enteric viruses in treated drinking water. /! pp/. E1111iro11. Microbiol. 47:1290- 1294. McTi g u e, N .E. er al., ( 1998) Giardini Cryptosporidi11111 pilo t spiking investigations: Re1noval achieved and risks for breakthrough. Denver, C olo. Awwa R esearch Foundation and American Water Works Association. National Water Research Institute/ American Water Works A ssoc iati on R esea rc h Foundation . (2000). Ultraviolet disinfection: guidelines for drinking water and water reuse. N SR I, Fountain Valley, CA. N HMRC/ ARMCAN Z_ Co-ordinating_Group, FRAMEvVORK FOR MANAGEMENT OF DRINKING WATER QUALIT Y: A Preueuriue Strategyfro111 Catd1111et1/ to Co11s11111er. 2001, National H ealth and M edical R esearch Council : Australia . Payment, P. , Trudel, M. and Plance, R. ( 1985). Elimination o f viruses and indicator bacteria at each step of treat ment during preparation of drinking water at seven water t reatment plants. Appl. E1111iro11. MiCl'obiol. 49:·J418-1428. Plummer, J.D. et al., (1995) . Removing Cryp10sporidi11111 by dissolved air fl otation . J . A WW A. 87(9) :89-95 . Robertso n el al., ( 1992) Surviva l of Cryptosporidit1111pan111111 oocysts under various environmental pressures. Appl. E1111im11. Microbial., 58(11):3494-500. Rochelle, PA, MM Marshall , J R Mead, AM Johnson, D G Korich, JS R osen and R De Leon. (2002). Comparison of in vitro cell culrure and a mouse assay for measuiing infcctivi ty of Cryptosporidit1111 parv11111. Appl. E1wiro11. Microbial. 68(6):3809-3817. Rose, J.B. el al., (1986) . !solacing viruses from fin ished water.]. A WWA. 78: 56-61. Uguen, C., et al. , Evaluation of viability and infeccivity of waterborne Cryp1osporidi11111 p111v11111 oocyscs.]. E11karyo1 . Microbiol. 1997 . 44(6) : p. 73S. Van Heerden,J., Ehlers, M.M. , Van Zyl, W.B. and Grabo w, W.O.K. (2003) . Incidence of adenoviruses in raw and treated water. Water R es. 37:3704-3708.


WATER

WATER - SECOND AND THIRD TIME AROUND J C Radcliffe / 11 Nove111ber a Natio11al Table 1. Wate r Recyc ling 20 0 1-2002. • Water Sensitive Urban Design Sy111posi11111 011 "WATER- The (WSU D) Guidelines introdu ced Region Effluent Recycled % (2003). A11stralia11 Dile111111 a" was GUyr GUyr orga11ised by the A11stralia11 The Options for Land Acade111 y of Tech11ological Sciences QLD 339 38 11.2 Based Reuse of STP and E11gi11 eeri11g . The a11die11ce NSW 694 61.5 8.9 Effluent co111prised over 200 professo rs, toprank prcifessionals a11d b11si11ess ACT 1.7 5.6 30 Urban Amenity Use exewti11es, who were exposed to Sydney - 7 schemes for irrigating VIC 30.1 6.7 448 over twenty 11atio11al and i11temaparks, golf courses. tio11al speakers coveri11g the whole TAS 65 6.2 9.5 Canbe rra - D untroon Military < (!n11111t of the critical tec/111.ical /1/td Co ll ege (1993) 20L/sec. SA 101 15.2 15.1 policy iss11es . O11tco111es J,-0111 the P e rth - Parks use at M cG illivray 12.7 WA 126 10.0 Sy111posi11111 will be processed by the Oval. Acade111y i11to a definitive docu111e11 t NT 21 1.1 5.2 Country Amenity Use for prese11/atio11 lo releva nt i./Oven1111 e11/ , i11d11strial and N a tio n-w ide - widespread use AUST fl11a11cial orga11isatio11s, 111e111bers for ovals, go l f courses, racecourses, cemeteries, recreation and 111i/l also be available 011 the Australia's Water Use areas (e.g. Yulara, NT) etc. A cade111y's website al 111w111.a/se.01~(!.a11. The following is a s11111111ary, prepared by the 70% is used by agricu lture, but th is water A Resource for Agriculture, Forestry Editor, based 011 the b11/let fon11al of the not read ily accessible to ca pital cities (This may yield enviro nmental benefits Powerpoi11t prese11/alio11 011 recycling, 111ade by except by Adelaide. but does not save drinking water). Dr John R adcliffe, Adviser to the Chief Summating the 22 maj or cities: Sydney - 3 schemes for irrigating agriculExewtive of CSJRO. His Sy111posi1m1 paper tura l enterprises. • Total Domestic use per annum - 1 200 will be published i11 1/1e above dow111e1!.I. ft is Hunter - recycled water -38% agric ulGL (including Gardens & To ilet fl ushing draw11 fro111 a 11111cl1 more detailed re11iew cif tural (55% industrial). - 658 GL). "Water Recycling" that Dr Radcliffe is 1111derCountry NSW - over 50 proj ects, mainly • Total Industrial /Co mmercial use - 576 taki11g for t/1e Acade111y, sponsored by the agricultura l. eg. Shoal haven 2GL/an, GL. A 11stmlia11 Research Co1111cil, lo be p11blished rising to 4GL/an nu m, for dairy pastures. by the Acade111y in early 2004. It fo llows a • Non-drinking reg uire ment - ? A CT - Lo wer Mo longlo - vines, golf, si111 ilar Acade111y review in 2002 011 "Pesticide The Initial Recycling Driver (excess flows to Burrinjuck irri ga ti o n Use in A11stmlia", copies of which are available reservoir). J,-0111 i1ifo@atse.org.m1. His prese11/alio11 dealt Environmental considerations reguired Melbourne - W estern Water developed with the wrre11/ status of recycling in A11stmlia, higher discharge standards for sewage Sunbu ty-Melton pipeli ne. q11oti1tgf,g11resfor 2002, 011tlini11g the vario11s treatment p lants. Th e options were: Country Victoria - Ararat (vineyards), categories <f recycli11g, reviewing the wn-enl devel• Expensive Biological Nutrient Removal Goulburn Val ley (d a iry p astu r es) op111e11/s in the A11stmlian States, and thm insta llations. Numero us others in Victoria - potatoes, discussing the iss11esfor thefi1t11re. • Extended ocean outfalls. turf, woodlots, tomatoes, flowers etc. • R ecycli ng fo r land appl icatio n rather Australia's Water Resources: Que ensland - W ide Bay wa ter (sugar, than discharge to rivers or sea . Recent Policy Perspectives turf). New Policy Drivers So uth Australia - On Northern Adelaide • Ecologically Sustainable Development Plains, Boli var Class A water provided by (199 1). • R ecognition that w ater resources were Water R eticu lation Services fo r Virginia • CoAG Water R eform (1994). declining - e .g. Perth. to vegetable gro wers - 12 GL/an. • First State of Environment Report • Wa t e r Conservation Strateg ies contracted, potential 24 GL/an. Southern (1996). developed in NSW, SA, Victoria, WA. Vales 2 GL/an. from C hristies Beach, class • National Water Quality M anagement • En v ironmental Objectives be ing B/ C delivered pressurised to grape growers. Strategy Guidelines (1996-2000). defined, ie. No New D am s! - e.g. WA Country - of 67 schemes, 11 are • N ational Land and Water R eso urces Welcome R eef Dam fo r Sydney deferred woodlots or agriculture. Audi t (2002). (2002) . • Senate - Australia's Management of • De-rating of Storages to provide water Proposed Agricultural Developments Urban Water (2003) . Victoria for the Environment. • The proposals of the Wentworth Group Melbourne - Western Treatment Plant • Recycled Water Strategies/ Guidelines (2003). Werrib ee to Balli ang, and Eastern - developed by most States (1993-2002).

1824

166.5

9.1

WATER FEBRUARY 2004

33


WATER

Treatment Plant to Sandhurst, Cranbourne, Koo Wee R up Echuca - Rochester: former "discharge" now via storage used in agriculture.

Table 2. Capital city water recycling 2001-2 .

State Capital SYDNEY

Tasmania

MELBOURNE

Brighton, Coal River Valley potential for horticulture, viticultu re, and turf. Midlands has best opportunity fo r recycli ng but has most salinity.

BRISBANE ADELAIDE

Queensland

HOBART

Aim was to take from Brisbane, Ipswich, and Logan 150GL/an. of Class A recycled water fo r horticulture/vegetables (Lockyer Valley), and class C water for field crops (Darling Dow ns). Capital cost $600111, annual operating cost $30111, so economically unviable. Substituting Water for Industry- Saving Drinking Water

Gladsto ne - 100% recycling to industry Sydney - Georges Ri ver Pipeline - 53 km Glenfield & Liverpool STPs to Malabar - (1 00ML treated water/ day for sale to industries en route). Illaw arra Wastewater Strategy upgrading Wollongong STP to produce 20ML/day for BHP Steel using Microfiltration and Reverse Osmosis. Brisbane, Luggage Point - M icro fil tration/Reverse osmosis plant, supplying up to 14M L/ day to BP-Amoco. Perth, Kwinana - New industries, (MF / RO) at Wood man Point STP, 5GL/annum below 50mg/L TDS. Third Pipe Residential Systems

For toilet flushing, garden, amenity horticulture. Sydney - Rouse Hill - 12000 homes, 4 .4ML/day. Olympic Pk/Newington - 2.2ML/day Adelaide - Mawson Lakes 10000 population - combined effluent and stormwater. Queensland - Ipswich 1.2 GL/an. from demo plan t to 20 homes, ovals, industrial park. Gold Coast - proposed PimpamaCoomera 150 000 residents project. Victoria - Aurora - WSUD housing estate being developed - 25 000 people. On-Site Recycling

Canberra - Domestic sized STPs in 6 houses fo r recycling - toilet / garden use, from 1994. Melbourne - Oa kl ands Park - self contained development. St Kilda - 236 uni ts, greywater and stormwater. Carlton - ACF building, in-house recycling. Gold Coast - " Healthy Home" Agnes Waters - 32 unit self-contained development, greywater and stormwater.

34

WATER FEBRUARY 2004

PERTH

%

2.3 2.0 6.0 11.1 3.3 0 .1

Sewer M ining

Melbourne - Compact sewer-minin g trials, Domain Gardens irrigation, and fill ing Albert Park Lake. Canberra - South well Park (5 yrs, 36L/sec). South Pine Q ld - demo. portable plant, Gold Coast .

N orthern Adelaide Plains - Virgin ia 7-15c/KL*· Sydney - Rouse Hill - 28c/KL (has led to incr. use?). Ipswich Water - Springfield - 43c/KL Christies Beach - Southern Vales 53c/KL*· SOPA/Newington - 83c/KL. *Supplied to retiwlator by STP operator llJif/,011/ charge. Versus Estimated Costs of Recycled Water: Ipswich Water Springfield (consultant) - $1.45/KL. Sydney, Olympic Park (operating cost only) - $1.60/KL. int eg r ate d hydrol ogic al sys t em (consultant) - $2.50/KL. Sydney, Rouse Hill - $4/KL. Melbourne Eastern Treatment Plant (consultant) - >$3.00/KL.

Recycling Stormwater

NSW - Olympic Park - Integration of eilluent and stormwater. SA - Salisbury Council stormwater management strategy - 36 wetlands, used for Council reserves incl. Mawson Lakes, and for selling water to GH Michell (woo lscou r e rs), and Hold ens car manufacture. Issues for the Future

T here is rapidly increasing interest in water recycling, with strong incentives to apply more recycled water to land. There are some risks: • Inadequate modelling for proposed applications. • Rising water-tables and salinity. • Waterlogging. Rising water tables are now evident in Virginia (SA) quarte rnary aquife rs. Discharge to land does not always lead to the best environmental outcomes. Vatying seasonal domestic and agricultural demands are unlikely to match the supply of recycled water from treatment plants without expensive storage or ASR, e.g. model of outside demand for water, Aurora subdivision. The Changing Driver

Water resource limits are now acting as the principal recycling driver, due to competition for water (urban vs industrial/agric .); more conservation of water for the environment; de-rating of water storages; opportunity to replace potable with recycled water fo r non-potable uses. Costing and Pricing Recycled Water

There is great variability in costing and pricing - no transparency in pncmg mechanisms . e.g. Pricing of Recycled Water:

How Does One Consider?

• The cost and source of capital? • The cost of environmental externalities? • The need for profitability (even for a governm ent enterprise)? • Pricing and marketing of recycled vis a vis drinking water? • The incremental cost of developing alternative water resources. Regulation

• Until 2003, recycled water, produced as part of Wastewater Services, was excluded from the CoAG Water R efo rm agenda. • We have inconsistent , inadequate regulation between the S t ates in Environmental, Planning, and Health standards. • We have inconsistent classifi cation systems. • There are conflicts of interest 111 government - treasury retu rn vs conservation needs. • Who can collect and sell recycled water (State or Local Govt?). • T here are disconnects between agencies - which lead to ponderous, lengthy decision-making processes, discouraging for investors. A Range of Other Issues

• Integration of rainwater, stormwater, treated eilluent, grey water - w ho owns what and who services what? • Treatment plants - big or small? . • Energy costs, greenho use impacts, Installation standards. • Experience learned overseas. • Public perceptions can be influenced by market opportunism (food, real estate,


WATER

votes), un e nc umbered by scie ntifi c knowledge' • H ea lth , public confidence - crucial for the future of water recycling. Interest by Government

• N at ura l R eso urc e Mana ge ment Ministerial Council (April 2003) - R eport requested on Water R ecycl ing & Water Sensitive Urban Design. • Environm ent Protection & H eritage Council (May 2003) - Requested updating of National Gu id elines for Water R ecycling in partnership with NRMMC and NHMRC. • P r im e M i ni ster's Sc ience, Engin eering, I nnovacio n C ouncil (Nove mber 2003) - Workin g Group presentation.

• M elbo urn e Water has stated that th ere is no immediate intention. • However, it has been successfully practised in Windhoek for many years, and now Singapore, under th e key driver of p o tentia l shor tage has co mm e n ce d production . It Is Essential We Get It Right!

This mu st be an over-ridin g fac to r. One publicised failure could undermine every recycl in g sche me. This would put at risk all the capital invested. There is no security of demand in the face of disaster.

Joh11_fi11ished off his prese11tatio11 by taki11g a hearty Slfll~f! Jro111 a bottle of Singapore's NE Wat er. (It had bee11 i11te11ded 10 rnpply bottles to each /1111c/1 table, b11t delivery 111as delayed 11111// later i11 the day, so delegates 111ere ~ffered a bottle to take home a11d 111a11y did so).

The Author John Radcliffe retired as Deputy C hief Executi ve of CS IRO in 1999, having pre viously been D irector- Ge neral of Agricultu re in Sou th Austral ia fr om 1985-1992, but is now retained as an Ho norary Adviser to the C hi ef Exec utive of CS IRO, john.radcliffe@cs iro.au

Objectives Announced

Sydney - R educe per capita water use by 35%. Canbe rra - 20% recycl in g by 2 0 13 (incl udin g Parli a n, e nc Ho use?) . Melbourne - 20% recycling by 2010. Perth - 20% recycling by 2012. Public Acceptance is Crucial

Consider: • Psyc h o logica l objection vs. th e co nservation ethi c. • N on-contact use preferred. • Issues of cred ibility, risk, trust. • N ee d to build community suppo rt. • What w e ca n lea rn fro m ove~eas experi ence. • The community must be given the faces and be involved in th e choice of strategies to be adopted - e.g. as being done by Gold Coast Water at prop osed PimpamaCoomcra deve lopm ent. The Ultimate Issue · Do We Recycle Back To Drinking Water?

le is techni cally feasible and safe. But it ca n evoke aesthetic insecu rity among potential recipients. However, it seems acceptable if it go es down a river before entering the reservoir - e. g. for Adelaide's supply, various upstream towns discharge co River Murray, and there are ocher local examples. (Ed: The Magic Mile agai11!) Current Status of Potable Re-Use

• Qld, NT are committed to no direct recycl ing co drinkin g water. WATER FEBRUARY 2004

35


WATER

AUSTRALIAN WATER CONSERVATION AND REUSE RESEARCH PROGRAM P Dillon, D Ellis Why Do We Need Such Research?

2014?

2004

Conservation and Re-use

Security of Australian city mains water suppl ies is diminishing due to population growth, capped catchments and aquifers, increasi ng climate variability, lowe ring of dam spillways, and environmental flow req uirements. Yet all ca pital cities discharge more stormwate r and trea ted sewage than they import from catchments. If irrigation fa rms had wa t er use effi ciencies as low as citi es they would be closed. Figure 1 shows the current position, where o nly 4% of urban roof rainwate r and stormwater is harvested and less than 1% of reclaimed water is reused w ithin cities. It also shows a possible future scenario where the draw on catchments could be hal ved, through a comb ination o f urban water conservation, use of rainwater and sto rmwater and urban re use of recla im ed water. Water stresses and physiographic features differ between cities so gross savings and the means of achieving them will also vary. Urban consolidation will also change water usage patterns. Po licy changes will be needed to a!Jow water su pplies to ada pt.

Water co11servalio11 <111d reuse ro achieve waler sec11re sce11arios req11ires research to ,,,.,de1pi11 policy changes. Investment

Majo r corporate water utilities are o bli ged to return dividends to state governments. In 2000/0 I WSAA utilities se rv icing 14.4 milli o n Aus tral ia n s ge n erate d $4 .7 billion in co m e an d returned S1.15 billion to governments. Under t h e COAG age nd a with volumetric water pricing, such pri cing and policy sign als are in compatible with seeming water supplies fo r cities. A revised basis for water pricing is essential to free up change. This may take into account separation of water and land as per the rural community. Capital investment of $1.8 billi on ($0.3 billion of which came from s ubdi v ider/developers) was committed to wa ter and wastewater infrastructure in 2000/01, and a further estimated $0. 9 billi on in stormwa te r assets. With some exceptio ns this binds consu mers to ex isting sources o f water

36

WATER FEBRUARY 2004

Urban use of reclaimed water

Rainwater/ stormwater use

new water from catchments and aquifers

400 kl

400 kl

Water conserved (retained in streams and aquifers)

Figure 1. The proportion of Australian capital city water supplies by source (a) in

2004 expressed as annual water consumption per property and (b) for the same volume of water, a scenario for 2014 showing potential for alternative sources and water conservation. (Note that equivalent volume for residential properties only is 260KL).

supplies for the next 50 to 100 years.

Research is 11eeded lo e11s11re viable s11stai11able altematives for this level of i11vesrme111. T his is needed quickly to reduce waste of water and mon ey, through integrated water planning. Conservation measures

Per capita use of water in most cities has declined over the last two decades. The simplest and cheapest water conservation measures have alrea dy been adopted and costs of future initiatives wi!J increase. There is a ,,eedfor research io larger the best optio11s, and rank these against other measures, taking current ex ternaliti es and tec hn o logy developme n t in t o account. Wastewater discharge

The volume of sewage treated , 1540 C L (in 2000/01), is 62% of the water supplied (2480 GL) varying between cities from 38% in P erth to 82% in Sydney, depending on use in urban irrigatio n and evaporative air co nditioning, and the extent of urban consolidatio n and wet weathe r and gro undwater in gress to sewers. Saline groundwater ingress ca n significantly increase the cost and viabi lity of water reuse. 36,000 Tonnes of nitrogen were discharged to the coast adjacent those cities in 2000/01, at an environ mental cost w hich is as yet unaccounted Further

treatment to reduce nutrient emissions will create wider opportunities for reuse with reduced impacts on grou ndwater quality.

Tradeojfs 11eed f,1rt/1er research . Stormwater harvesting

Rainfall va ri es between the major state capitals from 530 111111 in Adelaide to 1230 111111 in Sydney. However, the m ea n rainfall for the driest six continuous m onths ra nges from 1. 20111111 in Perch to 490 mm in Sydney. Storage requ irem ents for utilization of rainwater and storm water therefore d iffer widely betwee n cities. Besides tanks for roof runoff, subsurface storage options are proving economic in Adel aide for stormwater and reclaimed water reuse, and these need research to

enable applicario11 to a 111ider ra11ge of aq11ifers, source 111arers and target 111ater uses. The consequences of not harvesting and using ra in water are larger storm wate r p ipes and higher inc idences of flooding. ln most ca pital cities storm water and water supply systems are ope rated by different organ izations wi th little account taken of the benefits to whole systems by linkin g them . C lea rl y a holistic approach to water 111a1rngeme11t 111arm11ts research sin ce it ca n produce solutions for wate r supply and storm water management tha n are c heaper than looking at these systems sepa rately.


WATER

Progress AWA Water Recycling Forum's first national conference in Adelaide in October 2000 unanimously endorsed a resolution to establish a coordinated national water reuse research program. Under the auspices of a steering committee composed of representatives of A WA, CS!RO and CRC Water Quality Treatment, the Australian Water Conservation and Reuse Research Program (AWCRRP) was founded in 2003. This is in two stages. Stage 1 revie'ws the research in a number of fields identified to be critical to wider adoption of water conservation and reuse in Australia. See Table 1. Stakeholders were sought and work commissioned, and this will be presented in workshops in each state capital in Autumn 2004. Further stakeholders are needed. The second stage is to identify and initiate a national portfolio of innovative demonstration projects and develop the research program to support those. A framework to enable more sustainable use of water in Australian cities has yet to be adopted. Given that all cities face similar challenges, the synergies between knowledge gained in different cities, and the need for cost efficiency, a coordinated national research program is essential. Investment is needed from government at all levels, and water, real estate and finance industries, Linkages to international research programs in this field have already been generated to create even greater benefits. Forf11rtl1er i1!for111atio11 011 A fVCRRP sec the A T1VCRRP !l'eb page: w111w.cl111.csiro.a11/ priorities /11rba11 I awcnp. To become a stakeholder, please co11tact: Clare Porter, cporter@a111a.as11.m1 or Dm1id Ellis, AWCRRP 1vla11agcr. 08 8303 8420, Da11id. Ellis@csiro.a11

Acknowledgements The authors thank the stakeholders of AWCRRP, who at the time of paper preparation are: Australian Water Association, CSIRO (Land & Water, Manufacturing and Infrastructure Technology, and Healthy Country Flagship), Victorian Smart Water Fund, United Water International, Water Corporation WA, Queensland Department of Natural Resources and Mines, Northern Adelaide Barossa Catchment Water Management Board, Patawalonga Catchment Water Management Board, City of Albury

Table 1. Australian Water Conservation and Reuse Research Program - Stage one

research activities and international research links The big picture

Agricultural and Environmental Issues

Inventory of water conservation and reuse activities and issues in Australia.]0'111 Raddf!Jc, Project Dircctor, Australia11 Academy 1.!{ Ted1110/o.{!ical Sciences a11d E11,f!illeerillg. Australian water-sensitive urban design: recent developments, new knowledge. Tim Fletcher, CRC_{tn· Catd1111c11t Hydmloly Integrated water management: Amtralian case studies. Grace 1\:fitchell, CSIRO

Endocrine disruptors and pharmaceuticals. G11m15:-G110 Ying and Rai Kookmia 1 CSIRO Impacts on crop quality from inigation with reclaimed water. i\:lllm1y U11ko1'id1, DmJ1l Ste1•e11s1 G11a11_{!-G1w Yi11_g &Jim Kelly1 Adel.,ide U11ii•, CSIRO I} ARRIS Pty Ltd Impacts on soil, groundwater and surface water from sustained irrigation with reclaimed water. D,1ryl Ste11e11s Water reuse for horticulture: guidance for irrigators and industry development, management methods to improve water use efficiency and sustainability. Jim Kelly, Natio11al T,Vi1tcr Reuse Coordi1111tor1 Hartimlfllre Australia; A1111e-1Haree Bola11d1 ffic Dept Pri111My fod11strics; 1H11rray Cltapma11, La11d a11d Hlater Australia

Social acceptance

Factors atTecting public perceptions of water reuse. i\'111rni Pu, ]11li@e Kaercher, Blair Na11carrow, CSIRO Health and risk assessment

Health aspects of water conservation and reuse, and proposed new national guidelines. Tony Prlestlcy, CRC Hlafer Quality a11d 'Treatment The fate of viruses and other pathogens: understanding health risks in non-potable reuse of stonnwater and reclaimed water. Simon Toze, CSIRO Quantitative risk assessment workshop, covers health guidelines on water reuse. 'T'cd Gardner, Qld Depart111c11t 1f Natural Resources a11d 1.Hi11es Implementing new technology

Innovative management systems for domestic scale harvesting of rainwater and stonnwater, reuse of grey water, and onsite treatment of effiuent. Clare Diaper, CSIRO Review of National and State plumbing codes and changes required (to facilitate the above). Ray I-lcrl1ert, Gary Hlork1111111, Gr£:!? Ti11k, Grcc11Plll111bers, lvJPklSA a11d R11JIT U11iFcrsity

NSW, Brighton City Council Tas, City of Mount Gambier SA, City of Mitcham SA, Western Water Vic, Beaudesert Shire Council Qld, Wide Bay Water Corporation Qld, and Ipswich Water Qld. (Stakeholders have contributed to the program to make it possible, and receive copies of draft reports, progress reports and free invitations to stage one workshops.) Finally we acknowledge the support of members of the AWCRRP Steering Committee who have been involved in developing this program: John Anderson, Chris Davis, Peter Donlon, GeoffSyme, Carol Howe, Heather Chapman, Tony Priestley, Howard Gibson, Brian McRae and John Langford, and the encour-

Economics and contractual arrangements

Economics of water conservation and reuse, including externalities and life cycle costing. Darla Hatto111\1acD01111ld1 CSIRO Position paper on economic, institutional, policy and regulatory barriers to ctHcient urban water management in Australia. Darlii I-Iatto11 AlacD011ald, CS!RO Manual of contractual arrangements for reuse projects, supplier/buyer relationships. Andrew Sher1111111 & Astrid Di Carlo 1 Russell Ke1111edy Solicitors International Links

American Water Works Association Research Foundation, Water Reuse Foundation, Global Research Alliance, European Commission via Aquarec-Oz, UNESCO, WHO

agement ofWater Recycling Fonun State Representatives.

The Authors Peter Dillon is Coordinator of AWCRRP, leads the CSIRO Water Reclamation Research Team in CSIRO Land and Water, Adelaide, and is a founding member of AWA Water Recycling Fornm, peter.dillon@csiro.au, (08) 8303 8714. David Ellis is the project manager of the Environmental Projects Office Adelaide also located at CS!RO Land and Water Adelaide and Manages the Adelaide Coastal Waters Study and AWCRRP, david.ellis@csiro.au, (08) 8303 8420. WATER FEBRUARY 2004

37


Enviro 04 will have Visit the premier industry trade show on sustainability As you will see from the current Enviro 04 exhibitors list published below, the water contingent of the exhibition is as large and comprehensive as ever, covering everything the industry needs to manage its water resources sustainably. It also encompasses sustainability solutions from the air, energy, waste management and resource recovery sectors. At the time of

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writing on 23 January we have 191 exhibitors signed up for the exhibition and there are still more spaces on the floor. While attending Enviro 04 as a delegate costs from $500 to $1,650 depending on how long you go for and whether you are an AWA member, attendance at the exhibition is free. If you would like to go to the exhibition

as a trade visitor please fill out the form inserted in this edition of the Water journal or visit the convention website at www.enviroaust.net. If you preregister and attend you will avoid waiting in a queue and having to fill in extra forms when you arrive and also be eligible to receive a gift from us.

See sustainability solutions from these Enviro 04 exhibitors 2H Plastics Accurate Detection Acqua International Acromet Action Instrumentation & Control Air & Hydraulic Systems AIRCLENZ Air-Met Scientific Airvac AJM Environmental Services Alfa Laval ALLDOS Oceania ALS Environmental AMCOR Recycling Amdel Amiad ANOX App-Tek Safety Aqualab Scientific Aquatec Maxcon Arrow Scientific ASIRC ASTT Atlantis Water Management Austeck Australian Water Quality Centre Australian Water Services Bendigo Bank Bermad Water Technologies Biolab BL Camtek Technology Blobel Environmental Engineering Bluescope Steel BOC Brentwood Recycling Systems Bushman Industrial Butt-Out Australia CE Bartlett Campbell Scientific Canadian Consulate General Castle Mountain Zeolites Caterpillar Asia Pacific CDS Centre for Biological Info Tech, University ofQld CERAR, University of SA CH2M HILL Clean TeQ Cleanaway Clearmake Environmental Equipment Compo-Vern, Contra-Shear Separation Technologies Cooee Biosciences Coomes Consulting Group Credere Environmental Engineering Crown Scientific CSIRO Dakota Industries Datataker Department of Environment & Conservation (NSW) Department of State Development (Old} Department of Sustainability & Environment (Vic) Draeger Safety Pacific

Earth Systems Ecotech Ecowise Environmental Electropure Industrial EnviroEquip Envlrondata Environmental Group Environmental Resource Management Environmental Systems & Services EnvironOdour Enviropro Alternatives Envirorent EnviroRisk Management EPA (Qld) Flo-Dry Engineering Fluidquip Fox Environmental Systems GCM Agencies GEA - Westfalia Separator George Fischer Golder Associates GPS Online Grundfos Pumps Haestad Methods Halcrow Hanna Instruments HOMA Pumpenfabrik Humes Hunter Water Hydrosmart International IDEXX Laboratories International Chemicals Engineering lplex Pipelines IT Environmental ITT Flygt lwaki Pumps IWES John Holland Water John Morris Scientific Johnson Screens Lear Siegler Linpac Tankmasta Liquitek Lloyd's Quality Register LM Byrne Measurement Engineering Measuring and Control Equipment MEGTEC Systems Memcor Merck Mono Pumps Multiplex Constructions NanoChem NewScientist Norit Membrane Technology Odour Control Systems Odour Research Laboratories One Stop Garbage Shop Optum ES Orica OSMOFLO Ozmotech Palintest PANalytical Parchem Construction Products

PCPL - Patrick, Charles Permastore Tanks & Silos Pioneer Water Tanks Plastic Plumbing & Irrigation Supplies Proaqua ProMinent Fluid Controls Pryde Measurement Pumpability R5 Solutions (NZ) Regent Pumps REHAU Repeat Products River Sands Rob Laine Pumping Rockcote Rockwell Automation Rocla Pipeline Products RPC Technologies SAi Global Sewer Equipment Company Shieldcoat Sigra SITA Environmental Solutions Smartaflow Smith & Loveless (NZ) Sokerol Spirac Engineering Spraying Systems Sydney Olympic Park Authority Tech-Rentals TESTECH Engineering Thiess Services Treemax Tyco Environmental Systems Ultraspin United Water International URS VEGA Veolia Environnement Vermeer Australia Vinidex Visy Wallace & Tiernan Wallingford Software Waste Service NSW Waste Technologies of Australia Water Aid Water Industry Alliance Waterman Waterpac Watersave WedecoAVP Weir Services Westwater Enterprises Westwick-Farrow Publishing Wharington Willlbald Wind-Water WME Media Wonder Treat If your organisation would like to exhibit at the Enviro 04 Exhibition contact Rosalind Vrettas on tel. (03) 97 41 4679 or email rsvquitz@blgpond.net.au.


some serious water content Water: Planning for the Future Conference Program Update

AWA AUSTRALIAN WATER ASSOCIATION

By now you will have received your registration brochure and looked on the Enviro 04 website for details of the AWA water conference stream entitled Water: Planning for the Future. Here are some recent additions to the printed conference program:

• the wastewater stream has been strengthened with extra platform papers to cater for the interests of a large segment of the AWA membership • our one-day asset management workshop will be very topical. It will include an international speaker and be led by WSAA's Andrew Foley, with input from key Australian players including regulators, utilities and expert providers • there will be a strong topic thread for healthrelated microbiology throughout the program • the program includes some hard-hitting

water resource policy papers from a diverse range of speakers from farmers to academics that are sure to get you thinking. All in all, this AWA conference has a strong program with some serious water content that is imperative for any serious water practitioner to know about. The program has been steadily enhanced by the technical program committee. The event begins on Sunday 28 March with the opening ceremony where the GovernorGeneral of Australia, Major General Michael Jeffery, AC, CVO, MC, will officiate. After three days of conferencing the event will finish on Thursday 1 April with a choice of four technical tours to some very different facilities that are facing complex environmental management challenges.

Enviro 04 Convention & Exhibition Sydney Convention & Exhibition Centre 28 March - 1 April 2004

CONVENTION Sunday Official Opening Monday Conference Sessions Tuesday Gala Dinner Thursday Technical Tours EXHIBITION OPEN HOURS Monday 9 am - 5 pm Tuesday 9 am - 5 pm Wednesday 9 am - 2 pm

You can keep abreast of Enviro 04 news and program changes and also register online at www.enviroaust.net.

Thanks to Enviro 04 sponsors, registration is affordable The Australian Water Association (AWA) is grateful for the support of the Enviro 04 sponsors. It is this generous support that has allowed us to keep the registration fee affordable. We are especially grateful to the following gold sponsors who are prominent in the water conference stream.

CH2M HILL is a global project delivery company providing engineering, construction, operations and related technical and project management services to clients in numerous industries. Our work is concentrated in the areas of water, environment, energy, transportation, telecommunications, construction and industrial facilities. Water and wastewater projects are the core of CH2M Hill's service offerings and the foundation upon which the company was built. Call +61 (0)2 9950 0200, www.ch2m.com. Thless Services is one of Australia's most versatile, innovative and diverse environmental and utilities contracting organisations. Our operations include contaminated site remediation, landfill ownership, development and management, alternative waste treatment technologies, recycling and resource recovery, waste collection services, integrated waste management systems, water and wastewater

treatment, operations and maintenance, hydrographic services, utilities maintenance and construction (telecommunications, water, gas and electricity) and industrial maintenance. Call +61 (0)2 3002 9000, www.thiess-services.com.au.

Department of Sustainability and Environment manages Victoria's natural and built assets, including seven million hectares of public land and the native plants and animals that live there. It balances growth with conservation, plans cities and towns and is responsible for water resources. The Department works with the entire community to make sure that the way Victoria develops today doesn't limit it from growing tomorrow. Call 136186, www.dse.vic.gov.au. Bluescope Steel Limited is the new name behind COLORBOND® and the LYSAGHT® range of steel building products and the supplier of AQUAPLATE® polymer coated steel for water tanks. Recent scientific research confirms that all of the company's coated steel products are suitable for collecting rainwater for drinking purposes, making a combination steel roof and water tank a safe option for rainwater management. Call tel. 1800 800 789, www.bluescopesteel.com.au.

AWA also thanks the silver sponsors: • NSW Ministry of Energy and Utilities • URS • Veolia Water • ESI • Sydney Water • Natural Heritage Trust • Haested Methods and bronze sponsors: • MWH Australia • Thames Water Projects Australia


WATER

INTEGRATED WATER MANAGEMENT - PUSHING THE BOUNDARIES N Apostolidis Abstract This paper presents som e recent case studies where a co mbin a tion of new t ec hnolo g i es, improved understanding of wa ter use and com mitm e n t to integrated water managem ent has resulted in schemes with far greater self sufficiency, smaller ecological footprint and lower life cycle costs. The case studi es cover sm all villages to maj or new urban developments serving o ver 150 000 p eo ple . Th ey challenge the conventional approach to u rban wa ter m anagem ent planning and offer a mod e l for u se throughout Australia and the world .

O

COMMON W (/1.LT H

I UIUU Of MlUOtOlOCY

Average Rainfall -Annual

reducing the impact on the receiving waters.

M11imetres

Case Studies 3200

The fo l l owing paper p resents three recen t case 11!()() studies that have embraced the 1200 concept of integrated water 1000 management. The case studies ll()() represent three different scales GOO 200 Tow,wv,te MIO Camoow.,,1 • of ur ban d ev elopmen t . R ooo 500 500 ctu,""" -o,.,., eoo comm encing with the author's -400 Rid'ln"Dnd 300 own ho use, a sm all village GOO ew .,. 300 Wi·~ • 200 serving 40 p eople and a m ajor regional schem e proj ected to 200 serve up to 150,000 people. For th e pu rposes of this paper the three case studies have been designated: ll()() Based on a standard ·Y&af cl:mntok:>gy ( Hl6 1 io 1990} Bnsb1rne C ase 1 - The Gap H o use Copyriglt Commonwealth of Austraka, Bu-eau of Motoorology Case 2 - M anly Ecological ViUage Figure 1. Average annual rainfall in Queensland Case 3 - Pim pama-Coomera Key Words: Total Water Scheme Cycle, R euse, Sm art Sewers, provided for urban communities. By All three case studies are located in D emand Managem ent, fntegrated Water adopting an integrated approach it offers South East Queensland, one of the M anagement opportunities co deliver servi ces more fastest growing regio ns in Australia economically yet with a smaller ecologi cal Introduction It is recognised that such schem es are footprint. For exa mple the use of dependent on lo cal climatic factors . Integrated Urban Water Management rainwater and/ or dual water reticulation South East Queensland is a sub-tropi cal What Is It? wo uld help to reduce potable water zone, with average mo nthly precipitation Traditionally, the various co mpode1nand deferring the need for additional and evaporation summarised in Figure 1. nents of th e water cycle have been water sources and at the same time considered independently, ie Case 1 · The Gap House p otable water is harvested in a Potable Water There are many houses in this Rett culatton rural catchment and transported region w ith similar fea tures to a to meet urban water demands, the T he Gap H ouse, predom iwastewater is collected, treated nantly in the semi-rural fringes and discharged, and stormwater of major urban areas with large is collected and discharged. It is block sizes where reticulated becom.ing .increasingly apparent sewerage and to a lesser extent to water authorities around the r eticu l at ed water i s not world that this is not sustainable, provided. Moreover, th ere are and that the interdependences several properties w ith even between the elements of the more integrated water fea tu res water cycle need to be recog(The H ealthy Home, Gardner et nised and harnessed. 20kl Roof al, 2002). Th e Gap Hou se is Water Tank Int egr at ed wa t er included in this paper partly management involves a more beca use the informatio n is holistic approach to the way readily available to the au thor water, wastewate r and Figure 2. Schematic of The Gap House water and sewerage but more importantly to ill usstormwater infras tru cture is system . trate th e hypothesis of this 40

WATER FEBRUARY 2004

2,00 2000

...


WATER

w h en Bri sb a n e C it y paper that there are signifTable 1. Comparison of Water Use in New House and Previous House. Council called for expresicant be nefits to be gained Annual Water Use (Litres) s i o n s of i nte r es t to by incorporating these Previous House d evelo p an area w here The Gap House features at a regional scale . 2002 2003 conventio nal wa ter and T he Gap H o use is on.ly 650 ,000 sewerage infrastruc ture 320,000 Reticulated Water Meter Reading o n e ye ar o ld. It is located were very difficult and Estimated break up of water Use w ithin 10 km of th e costly to imple m e nt. T o 364,000 270,000 Indoor Brisban e C BD. Bein g a connect this develo pment 286 ,000 large b lock subdi vision 46,000 Outdoor to the C ity's sewerage 2 (6000 m ) the area is no t 110,000 Rainwater Tan k Supply syste m w ou l d h ave serviced by re ti c ulated 240,000 Effluent required the constructio n sewerage . H o wever, the 650,000 666,000 Total of a p ump station and subdivisio n is served by 6 km pressure m ain and re tic ulated w ater. Som e Table 2. Comparison of Costs to Owner Between New House and asso ciated sulfide control 2 4000111. of th e block is Previous House. fac ili ties valued in excess bu shl a nd a nd is not of on e millio n dollars. Annual Cost ( $) irri ga te d. A sche m atic o f Figur e 2 s h o w s a Previous House The Gap House th e water and sew e rage sc hemati c layout of the 2002 2003 syste m serving th e hou se village . is provided in Fi gure 2 . $633 $360 Water Charge The average block size As ca n be seen T he $450 Sewerage Charge is 500111 2 G ap House includes a 20 $80 On- Site STP annual maintenance fee A sch em atic layo ut o f KL ra inwater tank and an $42 Power cost for pu mp th e w at e r bal a n ce is o n-site trea tm ent plant. $980 sho wn Fig ure 4. An nu al cost of capital @ 7% Local regulations required $1083 $1462 A s c an b e see n Total th e o w ner to to discharge 2 fro m all the rainwater the effiu ent to a 250 111 ho uses is proposed co be irrig a tio n a r ea usi ng for this is that a househ o ld o n its own wil.l collected in a ce ntral tank, filt ere d and burie d d ripper pip es. Th e o w ne r at his have a negligible impact on th e bulk water disinfected and return ed to the houses for o wn cost in cluded the ra inwate r tan k and su pply systems and o n th e overa ll use in the kitchen, laund1y and bathroo m . extende d the irrigatio n syste m. to irri gate wastewater system. H owever, if a majority H owever, the first flush is dive rted to the all th e gardens via an unde rgro und o f households impl em ented the same storm w ater system The rainwater tank can dripper system feeding eac h new plant and m easures t he ir co mbined im pact would be to pped up by reti culated w ater from a ne w lawn area. W ater use is summarized be sig nifica n t, easil y m easu rab le and the city system in periods of extended d1y in T abl e 1 . credits can b e determi ned for implespells. m entin g such n1.easures . Brisbane Cou ncil T h e rain wa ter tank is used to supply Th e w astewater is treated in tw o parts; recognised th is issue and rece ntl y offe red the h ot wa ter syste m, th e laundry, and grey wa te r from th e laundry a nd a $500 reba te to households that installed to il et fl ushing . Th e rain water tank has bathroo m is coll ected separately and a rain wa te r tan k . provisio n for topping up w ith reti culated trea ted using an o n on-site syste m , wate r from the B risban e City system. Case 2 - Manly Ecological Village filtered, disin fected and returned to the R eticulated water is also used for kitchen , house for toilet flushi ng via separate toilet Th is development has atte mpted to a nd c o ld w ate r in b at hroo m s. All push the bo unda1y in new urban li ving srorage . bath roo ms are fitted wit h wate r sa vin g beyond integrating water management but showe r roses. T w o adults and three Waste fro m kitche n and toil ets is also co nside red transpo rtatio n and social tee nage c hild re n occupy the ho useho ld. termed blac k w ate r and this is treated in dim ensio ns. Th e d eve lo pment a rose a seco nd o n site syste m , fil tere d, disinTabl e 1 compares annual w ater use fected and discharged to an eillue nt between the new Th e Gap House sco rage fo r irri gati o n of site and t h e previo us ho use also in the sam e suburb. T he previo us house landscaping using unde rground was w ithin a sew ered area and had dripper system s. re tic ulated wa ter. The ho use was Stormwater from th e site is s mall e r but had si mi lar si ze p ass ed th r ou g h a se r i es o f landscap ing area and no w ate r o rname ntal ponds that sto re excess savin g de vices. T able 2 compares srorm wate r runoff Th ese provide th e an nual cost co th e o w ner some treatme nt b efo re release the between the n ew and previous rece iving e nviro nme nt. W ate r house. fro m the ponds can also be used to The above exampl e sh o w s that s u p p l e m e nt irrig a t i o n of w hile The Gap H ouse has resulted landscapin g. in 50% reductio n in wa te r use and Table 3 summ arises th e annual zero contributio n to waste lo ads o f w a te r balan ce for t h e Manl y the City's wastewater system the E cological Vil.la ge. As ca n be seen o wn e r has no t reco vered the full the village is able ge nerate 84% o f Figure 3. Schematic Layout of the Manly Ecological be ne fits that The G ap H ouse has th e wate r needs from w ith in th e Village. achieved for th e C ity. The reaso n WATER FEBRUARY 2004

41


WATER

development site. On an diffi cult (politically and Table 3. Summary of Water Balance for Manly Ecological Vi llage. average year only 16% o f the environmentally) to develop water needs of the village Source / Destination new surface water storages. Annual Water Use (ML/ yr) need to be imported primarily Supply Use Gold Coast W ater, (GCW ) to m eet the internal potable Precipitation - first flush the business arm of Gold 0.54 use when the rainfall is not Coast C ity C ouncil cha t Precipitation - balance 2.80 sufficient to meet th e p otable has responsibility for the Town water 0.30 water demand. C ompared to m anage m ent and deve lNet Internal Use (1. 7 MLcurrent standards of service opment o f the w ater and 1.52 ML from grey water) 0.18 the total village water demand w astewater infrastru cture, Externa l Use 0.13 is about 93% lo wer. recognized that the current Irrigation (to 6000m2) 2.22 T able 4 co mpares th e circumstances provided it Discharge off site 1.09 a nnua l hou se h o ld co s t with a good o pportunity to Excess Irrigation water (to reserve area) associated w ith th e Manly 0.02 fi nd a more integrate d Ecological Village utilising Total 3.64 approac h to servicing new 3 .64 on-site systems compared to u rban d evelopme nts in a transporting th e sewerage to way that ensures their longTable 4. Comparison of Manly Eco logical Village Scheme Costs th e C it y sc h e m e . Th e to Conventional Scheme. t er m eco l og i ca l estimated cost to transport the sustainability . Annual Cost Per Property ( $ ) sewerage 5.5 km to co nn ect Specifica lly, Gold C oast Manly to sewe rage sc hem e was Conventional W ater is now re-looking at Ecological Scheme $1. lm. (In so me cities the the way that all water related Village Scheme water utility is bound to servi ces are to be delivered, Capital cost for transportation m eet this cost and is paid by in cluding potable water of village sewerage to City all ratepayers not just those suppl y , w as tewat e r sewerage scheme $4,400 benefiting owners). le ca n be co llection and treatment, Sewerage Charge per property $250 clearly seen that the proposed effiuenc m anagem ent/reuse, Water Charge per property co n cept i s f a r mor e $25 $220 and sto rmwater drainage eco nomical then the con venCapital cost of On-site sys tems. Th e lo gic behind Infrastructure at village tional system w hich w ould $1075 this initiative is that if it can otherwise require considOn- Site STP annual maintenance fee be mad e to work, then $80 erable transportatio n costs to C oun cil will be in a mu ch Power cost for pump $42 stronge r position in th e connect th e village co the Total $1222 $4870 C ity's sewerage scheme . future to accommo date th e growth that will see the C ity It is usually these types of disc harges to the lo cal waterways chat triple in size from 500,000 people at drivers that allow schemes like the Manly m ake Gold Coast an internati o nal tourist present to over 1,500,000 over the next Ecological Village to flourish. The scheme destinati on. 50 years. components involve existing technologies While the C ity has in place plans to An integrated approac h to urban but require ho useholds to take on more develop additional water resources to meet water management offers th e opportunity responsibility in their operation. For many the growing demand it also recognizes that to pro v id e wate r, wa ste w ater and people this requires a change of li fe style this approach may not be sustainable over storm water servi ces in a manner that is and habits to make such alternative th e long term as it is becoming more ecol ogically mo re sustainable, more schemes sustainable o ver the long term. As w e see more of these type of developments, the technology will become more cost effec tive and robust and concerns with o n-site sc hem es will diminish.

Case 3 ¡ Pimpama-Coomera Scheme T he Pimpama-Coomera catchment is a major growth area in the Gold Coast C ity Council. T he total catchment area is close to 6,000 hectares and has a projected population capacity of around 150,000 people . D evelopment o f this grow th area w ill result in major increases in dem and for water resources and increased wastewater volumes. At present the Gold Coast is facing three major challenges; the worst dro ught in its history, significant urban growth and increasing pressures from regulators to limit th e w ast ewa t er 42

WATER FEBRUARY 2004

'I. M~"VUTt:D IIUNT MATlll.lL

-

toMalAT!OO,WATlflOTC:U

Figure 4. Schematic Manly Ecological Village Water Balance.


WATER

equitable and more cost effective to the overall community. Following a series of workshops with key stakeholder groups the study team identified the following in tegrated water management initiatives as being worthy of detailed consideration: • R ecyclin g wastewater to meet the o utdoo r hou seho ld uses of urban areas. T his reduces water demand and the need for mo re water supply and associated infrastru cture whi le at the sa me time red uc ing the am o unt o f po ll utants reachin g the waterways; • Promotion of new materials, systems, constructio n methods and tighter asset controls to all ow th e use of smaller pipes fo r sewerage collection and thu s lower construction costs; En couraging demand manageme nt withi n the house to reduc e overall water dema nd and the amount o f wastewater that is generated. The encouragement w ilJ in volve mandatory use of wate r saving devices and pricing po licies that promote water co nserva tion; • Promoting the use of less person-access chambers fo r gravity co!Jection systems by tak ing advantage of robotics w ith close circuit telev ision equ ipment th at allow maintenance and repai rs to be ca rri ed without req ui rin g person entry; • Promoting the use of rainwater tanks to reduce demand fo r water and the size of storm water pipes needed to co nvey storm water flo ws fro m urban develo pments; • U sin g the recycled water network to meet fire fighting needs th ereby significa ntly redu cing th e size of water reticulation pipes needed to m eet indoor household needs. A detailed review of current levels of servic e and design criteria used fo r new urban development showed that there are significant opportunities for improvement. These are discussed below: Opportunities to Reduce Water Demand

Gold Coast Water supplies approximately 350kL of water per property per year (960L/d) (WSAA Facts 2001) The residential water consumption is about 240kL per annum (660L/ d). (This figure includes multi unit developments. The wa t er co n sumption for d etac hed residential households is abou t 300kL or 815L/ET/ day.)( ET is Equiva lent Tenement) The difference is due to nonreside ntial uses and water losses from the system. The annual residential water consumption is below the Australian average (260kL) for major water utiliti es

Table 5. Opportunities to Reduce Residential Water Demand Water Use (L/ ET/ day)

Initiative

Comment

1,030

Current standard of service

This includes 120 L/ ET / day for UFW and 95 L/ ET/ day for plann ing buffer. 60% internal use , 40% external

870

Mandatory use of water efficient devices (dual flushing toilets , shower roses, front loading washing machines)

Assume 16% reduction in internal demand (or 20% reduction in shower, toilet and washing machine use)

530

Dual water reticu lation

Assume all outdoor use is met by effluent recycling

2701

Rainwater tanks

To supply laundry, toilet and hot water service

210

Tighter asset creation controls & better system mon itori ng

Reduce UFW by 50%

190

Apply 10% plann ing buffer on red uced demand

Table 6 . Alt ernatives to Fire Fighting Provisions. Comment

Fire Fighting Flow in Potable System

Initiative

15L/s@ 12m

Cu rrent Standard of service

1L/ s@ 22m

Home based sprinkler systems

Householder installs internal and roof sprinkler system. Wi ll require minimum 25 mm connection to house. Back-up connection to rain tank and/ or pool.

Nil

Fire fighting supplied by dual water reticulation system

Fire fighting requirement provided in dual water reticulation system . May need back up connection to potable water supply at effluent storage.

Table 7. Opportunities for More Efficient Wastewater Systems. PWWF Initiative (L/ET/ day)

Comment

4125

Current Standard of service

The figure incl udes 30% allowance for 1/ 1.

3750

Mandatory use of water efficient devices (dual f lushing toilets, shower roses , front loading washing machines)

2250

Use of smart sewers

Use of watertight , f lexible sewer pipe materials, no manholes, t ight asset controls and system monitoring. 30% allowance for permanent infiltration

1950

Use of smart sewers

Use of wate rtight, flexible sewer pipe materials, no manholes , t ight asset controls and system monitoring. 15% allowance for permanent infiltration.

Nil

On-site systems

Not permitted under current government legislation.

but above most urban OECD countri es. There are opportunities to further reduce water demand and GCW is implementing this through its Water Wise program. Key elements of the demand management program implemented by GCW includes:

Reduces flows to sewer

• Education; incentives; regulation; pricing • Encouraging the use of water-efficient appliances • Water restrictions , drip irrigation, vegetation suited to local environment (planting natives, etc. ) WATER FEBRU ARY 2004

43


WATER

Under th e current GCW co mmunit y owne d and Table 8. Proportioning of water demands. standards of service the water o p e r ated pl an t s. T h ese distributio n system and the Water Use Proportion Source option s ha ve n o t b ee n treatment plants are designed discarded from future considInternal Kitchen 10% Potable fo r 1030L/ET / day and the eration but have not bee n Bathroom 20% Potable sour ce of s uppl y at developed further in this Toi let 25% Rainwater or 930L/ET/ day. A detailed first phase of the project. Reclaimed analysis recently undertaken Laundry Opportunities through 25% Rainwater by GCW has found the wat er se nsit ive urban Hot Water 20% a ctu al r esidential wate r Rainwater design c o n s umption t o b e Externa l Garden use Varying seasonally Reclaimed 8 15L/ET/ day. Th e higher C oncern w ith the water figu re has been adopted to qu ality impacts from u rba n tunities to redu ce the allowance for Ill. acc ount for unaccounted fo r wate r stormwater runoff has changed the way Essentially this is a sm an er way of sto rm water collection is provided to new (UFW) in the system and to provide some servicing urban communities, thu s the buffer for high use areas and planning. urban develop ments. In the past the term Smart Sewers. Table 5 summarises the oppo rtunities primary objective was flood protection Table 7 provides a summa1y of opporfor reducing household water demand and stormwater systems were designed to tuniti es for more efficient wastewater from current levels. convey the flo ws to the nearest watersystems. cou rse as quickly and as effi ciently as As can be seen there is considerable possible . Other opportuniti es fo r more efficient scope to redu ce residential ho usehold wastewater systems were evaluated but the water dem.and by as much as 80%. This Under the concept of water sensitive is consistent with the fi ndings in the two study team ruled th em o ut for the time urban design (W SUD) the o bjective is to previous case studies. being as needing fu rther development. detain the pea k flows to the pre-develT he team needed to consider schemes that op m e n t leve ls and to introduce Fire Fighting could be implemented relatively quickly. landscaping and water guality treatment Fire fighting reguirements have a syst e m s to re du c e th e impa c t o f Two of the initiatives that were discussed signifi cant impact on the sizing of the stormwater discharge (both guantity and include on-site treatm ent systems and potable water re ti culation n etworks se rving urban developments. Under the GCW current levels o f service the water 100% distribution system is regu ired to supply a minimum of 1 SL/ s at a pressure head of 12 meters to any fire hydrant servicing C res i d e nti a l dev e lopm e nts. T h i s ~>, 80% .a reguirem ent essentially dictates the size of j the water reticulation pipes that make up 60% a. Q. to 90% o f the water network infrasbl tructure. The fire-fighting reguirem ent has ] a relatively minor impact o n the trunk 40% distribution mains. Table 6 provides a summary of alternatives to current fire fighting provisions. 20%

I

~

1

II

I

.E

Opportunities for More Efficient Wastewater Systems

In the last two decades there have been significant improvements in th e material used for sewer construction, monitoring systems, cleaning systems and construction methods. Despite these improvements, the design crite1ia used for sizing and planning new sewerage schem es have remained relatively unchanged. A significant component impacting on the capacity of sew erage systems is the allowance for stormwater infiltration and inflow (I/I). Under the current standards of service 60% of th e pipe capacity is reserved for this component. By using more flexible, watertight pipe materials and smaller/ less maintenance access stru ctures combined with tighter asset creation controls and better system monitoring, there are significant oppor-

44

WATER FEBRUARY 2004

0 '#0%

0

10

20

30

40

50

80

Volume (kL)

Figure 5. Size of Rainwate r Tank Versus Proportion of Internal wat er Demand Met. Table 9. Reticu lation development costs pe r househo ld. Summary

Scenario 1

Scenario 2

Scenario 3

Scenario 4

Wate r

Conventional

Dual Retie

Dual Retie

Dua l Retie + FF in Effluent lines

Stormwater

Conventional

Conventional

Rainwater tanks

Rainwater tank

Sewerage

Conventional

Smart Sewer

Smart Sewer

Smart Sewe r

Potable Water

$2,419

$2,021

$2,021

$1,606

$1,362 $2,021 $1,500 $2,643

Reclaimed Water Sewerage

$3,628

$2,643

Stormwater

$ 3,000

$3,000

$1,606 $1,500 $2,643 $2,40 0

Total $/ lot

$9,046

$9,270

$10,170

Rainwater Tank

$ 2,400 $9,925


WATER

period fro m 1983 to 1992 . This data set was considered to be Conventional IWM re p rese n tati ve of th e ra in fall Scheme Scheme pattern fo r the site and includes periods of drought and heavy $11.1 $13.0 Peak O&M Costs ($M/ year) rain fall. $515.2 $539.8 PV of Cap and O&M Costs (7%) On th e Gold Coast, the -$29.9 -$31.9 Peak Income ($M/ year) average rainfall is sufficient to $287. 2 $296.1 NPV (7%) completely replace th e potable water supply. However due to the uneve n distribution of rainfall and • R educes impac t on trunk stormwater limitations o n indi vidual storages, it w ill syste ms. be necessary to back up the supply. Th e For the purposes of this proj ect it was Rainwater Tanks required irriga tion fo llo ws an annual been assumed th at rain water wo uld be Within the contex t of th is study th e pattern w ith demand hi ghest in summer used to supply all no n- potabl e appli caW S UD m easure that had th e greatest and lowest in w inter. If the daily rainfall tions. R e tic ulated potabl e wa ter wo uld impac t o n th e water and sewerage infrasis above a given limit, no irri gation will b e pro vid ed to m ee t kitch e n a nd tru cture is th e use o f rainwate r tanks. occur. bathro om de mands and as a backup There is conside rable interest in th e use The m odelling showed that with the suppl y to th e rainwa ter tan k during o f rain wate r tanks througho ut Au stralia external de mand being m et b y reclaimed prolonged dry pe rio ds in th e fo rm a and co nsiderable literature published o n wa ter, up to 70% of internal demand tri c kle feed supply . the subj ect. co uld be suppli ed from rainwater tanks. Th e key be nefits th at rainwa ter tanks Tabl e 8 summarises th e ass umed With a 10 kL tan k, abo ut 11 OkL or 57% offer urban develo pme nts include: allocation of potable and rainwate r for th e of th e total ho useho ld demand could be replaced by rainwater. The res ults are above options in South East Qu eensland. • Suppleme nts po table water suppl y; summ arised fo r a range o f tank sizes as • R educes the peak flo w water d emand A dai ly wa ter balance model was used shown in Figure 5. to evaluate the effecti veness of introducing fro m th e ho useho ld; T o test the feasibility of th e above rain wate r tanks. Th e m odel used actual • Redu ces th e size o f sto rm water re ticinitiati ves four scenarios were de ve loped rainfall and evaporatio n data for a ten-year ulation;

quality) fro m urban development on the rece iving waterways . This in turn provides an oppo rtunity to use the detained stormwa ter benefi cially fo r landscaping or othe r uses. The concept ofWSUD is now being w idely accepted by local autho riti es throu ghout Australia and it is being incorporated in the planning approvals for new developm e nts.

Table 10. Summary Economic Ana lysis.

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WATER FEBRUARY 2004

45


WATER

and evaluated using a recent development as a case study. The results for this assessment are summarised in Table 9. T h e results sh ow that by taking advantage of new technologies and introducing some of the integrated urban water managem ent initiatives, the additional costs to develop such schemes are not as high as previously assumed. In fact by taking into acco unt th e potential savings in the h eadworks, the alternative scenarios would offer economic advantages over the convenci onal approach. Tabl e 10 compares the w hole of life costs of a conventional and one of th e preferred IWM scheme. As can be seen th e !WM scheme is a more ec onomic option if the headworks are included in the overall assessment. Key points to note from the economic analysis are: There is little difference in overall capital infrastructure co nstruction costs The !WM option has marginally lower ca pital costs, and lower operating and maintenance costs, than the 'business as usual ' case; The IWM options potentially have less income than Conventional scheme, as the potable water demand is less and th e reclaimed water used co substitu te this demand is assumed co be charged at a lower rate; In present val ue terms all the IWM option has a lower cost than the base case, even taking into accou nt the reduced m come.

Ecological Footprint Comparison Of Case Studies A major driving force fo r considering !WM schemes is the desire to reduce the ecological footprint of new urban developments. A simple system was devised in this paper co illustrate how the ecological footp rint measure could be used for assessing such sch em es. Th e system devised comprises three indicators: Water demand

Und er this indicator schemes are assessed on th e volume of water that has to be extracted from the environment. A valu e of lO would equal th e current level of service where all water is sourced from th e environment A sc heme that redu ced potable water demand by 80% would receive a value of 2. Waste Load to the Environment

This indicator measures the volume of waste that is disc harged to the receiving

46

WATER FEBRUARY 2004

Table 11. Summary of Options Eval uation . Case Description Study

1 2

3

Ecological Footprint Water WW SW Demand Load Impact

Total Eco. Foot print

Economic (Annual cost; Property)

The Gap House

1

5

9

The Gap House - Old

9

9

1

2

28 4

1462 1083 1222

3 10 Manly Ecological Village 1

Manly Ecological Vi llage - conventiona l

10

9

5

24

48 70

Pimpama-Coomera Scheme

2

3

3

8

1046

Pimpama-Coomera Scheme - Conventional

10

8

5

23

1126

environ ment. The current approa ch where 85% of the wastewater is discharged to the waterways and no additional treatment would result in value of S.S. A scheme that recycles al l the wastewater and uses the nutrients to grow crops (or supplem.ent potable water demand) is given a rating 1. Stormwater Water Quality/Quantity

This indicator assesses schemes for their impact on water quantity and quality in the receiving water from n ew urban developments. - A n ew development where all th e native vegetation is removed and replaced with paved surfaces and concrete drains will receive a rating of 10. A n ew urban development with appropriate landscaping and storage that limits water quantity and quality impacts to predevelopment levels would receive a valu e of l. C learly there are more sophistica ted n1.easures of ecological footprint. T hese are more comprehensive and usually take into account oth er facto rs such as energy, transport, social dislocation etc. The indicators used in this paper are considered sufficient to illustrate the hypothesis in this paper. The three case studies were assessed using the above criteria and the results are summarised in the T able 11.

Conclusion The followin g conclusions have resulted fro m these studies: • Integrated water management (!WM) offers significant opportunities to reduce the ecological footprints from new and existing developments; • Contrary to popular p erceptions th e adoption of !WM m easures need not cost more. In fact with good planning IWM at th e start of new urban developments is more li kely to produce a more economical solution;

• To realize the full ben efits from !WM th e concep t needs co be embraced at a regional level to make a noticeable impact on headworks. • To adopt !WM does not require any new technology, it is a managemen t and education issu e.

Acknowledgements The author thanks Gold Coast Water for allo w ing th e publishing of the discussion paper and GHD for the opportunity to present this paper.

References Man ly W est Ecological Sustainable R esidential Development, October 2000, GHD Pty Ltd, Brisbane Australia Pimpama-Coomera Integrated Urban Water Master Plan , Discussion Paper, N ovember 2002, G H D Pty Ltd, Brisbane Aust ralia The Healthy H ome - A Step T owards G reening Paradise, 2002, Ted Gardner et al, .Brisbane Australia WSAA Facts 2001

The Author Nick Apostolidis is the water business stream leader and a Director of GHD. Nick's particular interest is in strategy development and water recycling. H e was chairman of the Q u ee nsland Water R ecycling Stra t egy R ese ar ch and D evelopment T echnical Advisory Group. E-mail: napostolidis@ghd. com.au This paper is a11 edited versio11 of a paper presented at the lllternatio11al Water Association co1ifere11ce i11 Spain. (A subsequen.t prese11tatio11 011 the Pi111pa111a-Coo111era scheme ,vas rnade by Sha1111 Cox a,1d David HaJ11lyn -Harris at the Natio11al R e-Use co1ifere11ce i11 Brisbane, September 2003). O11er the last 18 months Cold Coast Water has bee11 developing a co111prel1e11sive 111aster plan through a multi-stakeholder advisory co111111ittee. The master pla11 has been. published a11d distributed for public co111111e11t. The plan is 110111 being finalised fo r consideratio11 and adoption by th e Cold Coast City Co1111cil.


B

WASTEWATER

TREATMENT OF MUNICIPAL LANDFILL LEACHATE BY SBR D de Kretser, D McRae, S Bateman Abstract

Table 1 . Leachate characteristics.

A four month leachate treatment trial was conducted at a landfill site in M elbourne. The resu lts showed that the sequen cin g batch reactor (SBR) was the preferred treatment process, as it achieved th e h ighest ammo nia removal rate and provided the most stable operation. Details of its performance are provided. The adopted design ammonia load ing rate was 0.09 g NH 3 / g VSS.d, and the design MLSS was 2500 mg/ L.

Parameter

Introduction To prevent leac hate from leav in g landfill sites and potentially pollutin g th e sur rou nding gro undwat er, leachate extraction and treatment is becoming an operating li cence requirem ent for man y landfilJ operators. Leachate characteristics ca n vary significan tly between sites, depending on the materi als comprising the landfill. The Pioneer la ndfill in C layton Sou th , M elbou rne, acce pts muni cipal and commercial wastes, that have a hi gh proportion of waste paper from offices. T he landfill generates leac hate with high ammonia co ncentrations wh ich must be treated before it can be discharged to sewer. Pi oneer engaged Kellogg Brown & Root Pty Ltd to design and sup ervise a pilot testing program to detennine the preferred treatm ent process and its key design parameters. Th e results from the trials showed the sequencing batch reactor (SBR) to be the preferred process . This paper provides an acco unt of the performance of the SBR.

Plant set up, operation and monitoring T he pilot scale SBR consisted of a single 170 L tank. T he plant was seeded with nitrifying sludge from the Pakenham Sewage Treatment Plant to an initial MLSS concentration of between 25003500 m g/ L. The tank was equipped with a 200 mm membrane diffuser to aerate and mix the contents of the tank. Th e SBR was operated in the following way: • Leachate was added once per day every day except Sundays • The pH was adjusted once per day to between 7-8 by adding soda ash

Well 1

Well 2

Well3

Domestic sewage

35

Ammonia (mgN/ L)

1200

2500

3300

TKN (mgN/ L)

1300

2700

3500

45

COD (mg/ L)

2000

8000

10000

450

BOD (mg/ L)

130

1000

2400

200

7.2

7.8

7.9

7.4

TDS (mg/ L)

7000

13000

34000

1000

Alka linity (mg/L as CaC03)

8000

12000

15000

200

pH

• The contents were aerated for 23 hours and th en allowed to settle • A volume of treated leachate equal to the volume of leac h ate added the previous day was decanted from th e tank. Samples of trea ted leac hate were analysed for ammonia, nitrate, nittite, pH ,

E A

R

T

dissolved oxyge n, temperature, MLSS, TDS and SVI. Durin g the course of the trial, certain m od ifica tions were made to th e basic ope rational parameters in o rder to improve the performance of the plant . If testin g showed an increase in the effluent

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WATER FEBRUARY 2004

47


WASTEWATER

ammonia, indi cating that not all of the aim11onia added the previous day had been nitrifi ed, then the vo lum e of leachate added was either reduced or stopped until the effiu en t ammonia levels reduced. Correction of pH with soda ash was in itially done manually; however it was later changed to set point control by th e installation of a pH controller an d dosing pump. The aeration pro cess was changed from consta nt aeration to intermittent aeration using cycles of 4 hr aeration fo ll owed by 2 hr non-aeration to allow som e denitrification to occur in the SBR.

250 , - - - - - - - - - - - - - - - - - - - - - - - - - - - - ~ 2500

• 200 + - - - - - - - • Ammonia t - - - - - - - - - - - - - - - - - -->-=---+ 2000 Nttrate pH control

• I Nitrite

.s

: ::~2:dded

-

·- - ~

SBR Performance The overall performance of the SBR plant is presented in Figures 1 and 2. Figure 1 show s the ammonia, n itrate and nitrite concentrations in the effiu ent from the plant over the fou r month trial period. Figure 2 shows th e ammonia loading rate, th e sludge settleability (as measured by the SVI) and the MLSS over the sam e period.

••

.

..

48

WATER FEBRUARY 2004

29/01/2003

1000

. .l ~·...1..1 ..J. i:"'""+:,1- - -- -- - - - - - l - 500

18/02/2003

10/0312003

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30/0312003

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z

f"' g

z

I

temperature operation ••

1500

Shock loading

+ - -ti,v ~u"r11- - ----+---J.

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.

"i ~

z

0

19104/2003

9/0512003

Oate

Figure 1 . Effluent quality.

Figure 2 shows there was a gradual decrease in the MLSS concentration in the SBR during th e firs t two m onths of operation. T his decrease is possibly due to a combinati on of th e degradation of organisms which could not tolerate th e increased salin ity, and insufficient ca rbo n in the leac hate to maintain the original biomass concentration (as th e F/ M ratio was typically less than 0 .02/ d). Therefore, although the mass of ammonia removed each day duri ng this period was relati vely stabl e (data not shovvn), few er bacteria were present to ac hi eve th is, resu lting in a higher am m onia loading and removal rate per gram of solids. During this period it is possible that a se lecti ve pressure was exerted on the biomass with preferential selection of nitrifying organi sm s.

am m o nia was oxidised to n itrite, whic h reach ed a peak valu e of 580 m g/ L, b efore decl ining to very low levels. Anthonsien et al (1976) and Ruiz et al (2003) reported that high conce ntratio ns of free ammon ia (FA) and/ or free nitrous acid (FNA) ca n be to xic or at least inhibitory to th e various gro u ps of nitrifiers. Inhibition of Nitrobacter (which converts n itrite to nitrate) can occur for FA co ncentration s of0.1-1.0 m g N / L, or FNA con centrations o f 0.22-2 .8 m g N / L. Using t h e eq u a ti ons from Anthonsien et al, the va lues of FA and FNA were calcu lated . The resu lts showed th e FNA valu es range d from 0 .6-3.4 mg/L during this p eriod w hich is likely to ha ve inhibited N itrobacter leading to the accu mula tion of nitrite. The concentration of FNA is particul arly dependent on the pH. As the p H o f the SBR pri o r to the additio n of the auto m atic p H control system was often b elow 7 , the low pH is likely to have been the ca use of the presence of FN A and therefore th e process inhibiti o n. An examination of th e plant records d uring the period w h en th e n itri te conce n-

Nitrite accumulation and process inhibition

For the first month all of the ammon ia was fu lly oxid ised to n itra te. H owever from early February to early M arch , there was a ch ange in the effl uent nitrate / nitrite ba lance (see Figure 1) . Duri ng th is time virtually all of th e

3e0,0 , - - - - - - _-_-_ -_-_- - - - - - - - - - - - ,.: - - - - - -h - o_ck_ ___, 0.210 8

Effect of rising TDS

Th e commissioning phase of approximately two weeks involved slowly increasing the amount of leachate added . Du ring this time the effiuent ammonia remained low, and the ammonia loading rate reached 0.10 g NH3 / g VSS.d (see Figure 2) . Du ring this period the TDS increased from around 500 mg/ L in the seed sludge to more than 4,000 mg/ L (data not inclu ded). It is likely that this rise in TDS eventually caused a rapid decline in plant p erformance, as show in the initial effiuent ammonia spike in Jan 2003 (Figure 1).

••

E 100 t----<,___ _ _--::;. ; - -...."'-::-Mla-+-1•.-~

50

• ••••

.... . ..-.

~

Leachate characteristics Leac hate fo r the trials was obtained from three wells installed into o ne of the recently closed landfill cells. Due to difficulties with the leachate supply during the trials, various bl ends of the th ree sources of leachate were fed to the pilot plants . T able 1 shows the typ ica l quality of the leachate extra cted from th e three wells after they had been operating fo r several weeks, as well as typical equiva len t va l ues for d o m est ic sewage fo r comparison. Th e potential va ria tion of leachate characteristics is well ill ustrated by the diffe rences in the values presented in Table 1. The table highlights two issues. The first is the importan ce of co ndu cting extensive testing of th e leachate to gain some u nderstanding of the potential vari abili ty before design in g a leac hate treatm ent plant. T he second is the degree of adapta ti on necessa ry for biomass sou rced fro m a domestic activated sludge plant.

••

I

•.•• -J. ~ 150 t - - - - - - - - - - - - - - - - -+ -.•.--·J·-L_•____.L___ ~

300.0 + - - - - - - 1 • ~~~S/10 t - - - - - - - - - - -....,. L•;_;wrn,:=:a,---load --1ln.:. g- ~

t

h

2000

pj I

ii

... •

, - ·----:=-=-~ 260 0

- •-L_ ••_d1_n _

r•

• • t-----··-:.=-.---•._;:.•;•;.______,j-----,.-~,a::- •-.-• ---i

1&0.0 100,0

.,,

_;P:.:H ::.:co:.:n..:. tro ::..:l.:;:1y ::.:1t::.c1m _ __.:'t----• pe _ ra_rto_n! -- - = ••:...__-l 0,200 added 24 March

a... •·.. •

r 0.HIO

0,100

t.- - - - - - - - - - - -.--. - +-.z....____ _ __:..._•:..._~

·~· .... ······.--.. •

• •• ,.. .1 •

.1

&o.o- ~- - - . - -.-.::.-..._..- ~...__ _ ....__,-.•,-I--• .r-:;-.rrr ..r;..:.rq.,r--J;r . '

-

o.oeo

o.o+ - - - ---- - - - - , - - - - - , - - - - - - . --+- - - - - -- -..1. o.ooo lill112003

lli!ll /1003

11/0211003

10/03/1003

0,i.

Figure 2. SBR Pe rformance .

30103/2003

10.,..12003

1110112003

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WASTEWATER

tration d eclin ed (which o ccurred before the pH contro l system was installed) showe d that the only signifi cant change was an increase in te1nperature of 5-9 degrees C. It is therefore postulated that this temperature increase m in imised th e inh ibitio n effects an d allow ed th e N itrobacter to process the accu mulated n itrite thro ugh to n itrate. pH control

Wh ile there was a slow improvement in the p erfo rmance of the SBR up to midMarch, analysis of the p H and DO data reveale d that manual pH control of the SBR was not effective, resulting in the ni trifi ca t ion p rocess o nly op erating efficien tl y for th e fi rst 6 hours after pH adjustm ent. However once the p H control system was install ed o n 24 March, th ere was an imm ediate drop in the effluent ammonia (Figure 1) and within four weeks there was a four -fo ld in crease in the ammo n ia loading rate, from 0.05 to 0 .20 g N H 3 /g VSS .d (Figure 2) . The improved perfo rmance of th e plant also resulted in the MLSS increasing fro m 1300 m g/L to aroun d 2300 mg/L w hen the trial was stopp ed. Low Temperature Performance

Performance at low temperatures (15°C or less) was tested for two weeks from mjd to late A pril. The resu lts showed that the SBR could o perate at a loading rate of approximately 0.09 g N H 3 /g VSS.d at 14l 50C, while still producing treated leachate w ith a max im um effl uent ammonia concentration of 50-75 mg/ L. Performance under shock load

Fo r three days from 30 Apri l to 2 May, th e SBR was su bj ected to a period o f extend ed high loadi ng. Over th is period, the SBR achieved an ammonja remova l rate of m ore than 0.15 g N H 3 /g VSS.d. Thus th e SBR showed that it woul d be capable of handJjng an extended hjgh load, such as may occur if the leachate concentration were to in crease over a few days, for example due to alterations to th e flow patterns through the landfill , or a rel ease of a previo usly contained substance in the landfill (e.g. breaching of a conta iner due to corrosio n).

yield to be calculated. The estimated sludge yield was fo u nd to b e 0.22. T his is well below that of a ' normal' biological community in a sewage treatment plant, but reflects the likelihood that the majority of the nucrobial commu nity in the SBR were nitri fiers w hich are known to be mu ch slower growing.

Conclusions A four- mo nth pilot trial was completed to identify the preferred process con figuration and to determ ine the values of the key design parameters for the fu ll scale plant. T he results showed that th e SBR was th e most effective process, providing the highest anm101ua removal rate and the most flexib le process configuration. T he adopted design am monia loading rate was 0.09 g NH3 / g VSS.d , an d the design MLSS was 2500 mg/ L. Th e ben efi ts of u ndertaking the pilot trials extended beyond the obtai1u ng of the above information. Valuable experience was gained w ith several of the issues likely to affect the ful l scal e operation , such as: • th e tim e reg uired for the biomass to acclimatise to th e leachate environment (in partic ul ar the effect of increased salinity) • th e impo rtance of maintaining th e p H in the optim um range • th e effect of temperatu re o n the ra te of ammo nia removal • th e potential proble ms with process inhibi tion if am monia and nitrite concentrations become too high. With the information gained from the pilot trials, it is now possible co proceed with the design of the leachate treatmen t p lant, w ith a good understanding of the likely issues to be faced du ring commissioning and when the plan t is fully operationa l.

References Anthonisen AC, Loehr R C, Prakasam TBS and Srinath EG ( I 976) Inhibi tion of nitrifi cation by ammon ia and nitrous acid. J. vi/at. Pol/111 Co11/rol Fed. 48, 835-852. Ruiz G , Jcison B, and Chamy R (2003) Nitrification with high nitrite accu mulation for the treatment of wastewater with high ammonia concentration vi/at Res. 37 , 1371 1377.

Sludge yield

The Authors

Although there was no specific wasting of sludge during th e tria ls, and therefore no calc ulation of slu dge age, the performance of tbe SBR fro m late March to late Apri l 2003, where all of the ammonia was processed an d th ere was a relatively steady growth in the MLSS concentration, allowed an estimate of the overall sludge

Dale de Kretser is a senior process engineer with Kellogg Brown & Root Pt y L td (e m a il da l e .d e kr e t se r @ hall ib urton .com ). Don McRae is a principal engineer with Kellogg Brown & Root Pty Ltd. Sam Bateman is a proj ect manager w ith Pion eer Australia W aste Management Pty Ltd.

Analyse for Anions - Fluoride, Chloride, Nitrite, Bromide, Nitrate, Phosphate, Sulphate ... Cations - Sodium, Ammonium, Pot assium, Calcium, Magnesium, Lithium, Strontium ...

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WATER FEBRUARY 2004

49


m

BUSINESS

WATER QUALITY RISK ASSESSMENT AND MANAGEMENT IMPLEMENTATION EXPERIENCES M Chapman, P R Nadebaum, G Finlayson, S Carne Abstract D efinition of safe and aesthetically acceptable drinking water by m easurements at customer taps has come under increasing scrutiny as understanding o f w ater- borne disease events and scientific evidence to quantify risk assessments has improved. In response, review of both the World Health Guidelines (WHO) and the Australian Drinking Water Gui delines (ADWG) aimed at incorporating useful risk assessment and managem ent system advice is now in progress. T he ADWG approach is known as the "Framework" and was developed by the Cooperative R esearch Cen tre for Water Quality and Treatment. The two senior auth ors of this paper were involved in that project. This paper summarises som e of the authors' experience with about twenty Australian and New Z eala nd w ater utilities mainly over the past fiv e years o n implementation of risk assessments, developing Hazard Analysis and C ritical C ontrol (HACCP) plans and structuring ove rall Water Quali ty Mana gem e nt systems. T he focus in this pap er is discussion of key processes used and tools developed to assist in the tisk identification and assessment phase . The tools include preliminary expert systems which help water authority staff complete their own identification of important hazard (e.g. turbidity, pathogens) . Other tools help defin e the likelihood of particular hazards (e .g. Cryptosporidium) arising for each unique catchment, raw water dam and water treatment arrangem ent. What has been learnt from completing Q uantitative Risk Assessm ent (QRA) is also discussed.

Delivery of Effective Risk Assessment Application of "Expert" Systems

M any water utilities in Au strali a have a relatively large number of small water supply catchm en t- to - tap systems to manage. This factor plus a desire to use self assessm ent techniques to achieve water utility staff commitment to a risk based approa ch to managing water quality 50

WATER FEBRUARY 2004

These are worded to allow easy answers from nonexperts. Eg.

Ask a number of YES I NO questions.

Does the catchment have farming? Does the treatment process indude UV?

Captures current thinking on appropriate risk reduction .

Rule Based Knowledge Engine. Covers wide range of hazards.

Eg. "Catchments with cattle have a higher risk of Cryptosporidium, which could be controlled with UV."

Generates Output

Which hazards appear to be in control, and what the crit kOal controls are, together with guidance on what is important?

A

Eg. "UV is a critkOal control for Cryptosporidium in this system ". A dose of 40 mJ/cm' at end of lamp life is required. Reliable power supply is important.

B

Which hazards do not appear to be control.

Figure 1. Expert System For Wate r Quality Risk Assessment.

m ea ns a relatively simple computer spreadsheet based system to identify and ran k risks has appeal. T he authors have developed a preliminary model, whi ch is currently being tested in a water utility . Figure 1 illustrates the approach taken . Similar work has been carried out in N Z (Carne and Chapman, 2002). Factors to ensure good quality risk assessments

The experien ce o f th e authors is that a qualitati ve risk assessm ent based on AS436 0 (risk assessm ent) principles bas significant advantages compared to other approaches. However, to gain fu ll benefi t from this systematic and rigorous methodology it is important to use a workshop approach. Participants sho uld include se ni o r staff from op erations, asse t managem ent, planning and water quality monitoring/troubl e shooting areas. Development of an agreed schematic of th e water supply system as part of "understanding the sys ten1" step in AS4360 is essential. It needs to show likely sources of hazard and existing controls as well as ho w water moves through the system. That is, all risks may be low at

customer taps but particular risks can be hi g h ju st u pst r ea m of a ce rta in co ntrol/barrier po ints. For example , controls such as set- back distance of septic tanks from watercourses, minimum volumes in dams and locked tank batches may be just as important as reliable disinfec tion. Defining ri sk s followin g catchment, dam outlet, treatment and even service reservoir interfaces after relevant upstream controls are considered pro vid es an importa nt connec ti o n between the risk assessm ent phase and the j ustifica tion o f critical control points in subsequ ent HAC C P plans. T his step should also includ e evaluation of existing water quality, custom er complaint, bu rst main, incidents of failu re, unplan ned maintenance and catchment land use data. T his helps define likelihood and consequ ences for im portant hazards. Ex p eri e nce bas sh own that the following is also important: â&#x20AC;˘ A CEO 's public con1mitmen t to risk assessment as a priority and , if possible, attendance at a fi rst workshop. â&#x20AC;˘ H aving an indep endent risk assessment workshop facilitator who runs the hazard


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and risk workshops co m inimise changes in m eth odology and perceptio n of w hat is a h igh and low risk. • Always visiting the catchment to collect and assess data and inte rview and explain the risk assessm ent process to th e relevant operatio nal staff prior to any workshops. • Ensu rin g all worksho p participants agree o n how eac h water supply system wo rks and w hat each o f the terms in risk assessm en t m ea n (e. g. likeli hood , source, hazard , severity, risk significance and controls) . We have also fo und that a nu merical risk scori ng process tends to be confusing. lt suggests a greater accuracy than th e q ualitati ve risk assessment perm its. Most worksh op participants seem co find the "low" to " very high" rating approac h in th e Fram ework easy to understand and a consistent basis fo r j udging the leve l o f risk. l.t is also impo rtant to co nsider both health and aesthetic water q uality risks. Th at is, community acceptan ce o f fi ltratio n and asso ciated high er co sts for water is often dri ven m ore by desire fo r improvem ent in aesthetic water quality than p erception of health risk. Finally a separate workshop to consider th e impo rtan ce and effectiveness of controls is o ften helpful for defi n ing the critica l con trols in the catch ments, dams, treatment pla nts and distribu tio n system . For example, o f th e many con trol activities involved in a repair of a burst pip e is fl ushing just before recu rn ing th e pip e co service and this is almost universally seen by opera tors as the critical con trol co mi n imise the risk of contamination. Quantitative Assessments

T h e approac h t h e au th o rs h ave develop ed to help quantify water quali ty risks has foll owed two lin es o f development: • Se m i-qua nt ita ti v e m o d ell in g for Cryptosporidium and Faecal S treptococci. • Form al quantitative risk assessm ent incorporating event trees fo r each so urce of risk combined with consideration of so cial , eco n o mic an d o peratio n al/ en viro n mental cost im pa cts (" triple bottom line" costing) Generally, these tech niqu es provide either a more quantified view o f the differ enc e in ri sk b e tw ee n se ve ral improv em en t options compa re d to continuation of the scacus quo or a basis for sensitivity analysis. Semi-Quantitative Modelling

Whe re a good understanding of catchment activities, flows in wacerc o urses, r ese r v oir s trat i fi ca tio n / shortcircuiting potential, treatment plant

REQUIRED LOG REMOVAL (TO ACHIEVE 0 002 oocyslsll.) • 1 TO 2

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performan ce and locati o n and size of po int sou rces of Cryptosporidi11111, Ciardia o r Faecal Streptococci are available this modelli ng approac h base d o n m ass balance can be useful. It provides a means co:

• C ompare optio ns fo r improvem ent options particularly in relati vely comp lex inh abitated ca tchment systems w ith a series o f raw water sto rages. • Und e rtak e se n sitivity an alysis o n sources, loads o f pathogen, decay rates and

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dilution/settling effects, plant p erformance and infectivity assumptions. T his model developed out of earlier work by the two senior authors on more complex probabilistic approaches, C R C risk assessment research and work on recreational water quality sta nda rds (Nadebaum 2000) Scharfenaker 2003). Because there is substantial uncertainty about the probability distributions used in such analyses it is difficu lt to interpret the outcomes. T he mass balance approach shows how available research work is lin ked together to explai n what is likely to be happening and why. It has also been foun d co be useful in communicating "what if' scenarios to people who are not experts in the area. A large body of scientific data has now been assembled covering different aspects of Cryptosporidium, Ciardia or Faecal Streptococci. For example, it is fairly clear that infected calves for Cryptosporidium can generate about 10,000,000 oocysts/gm of faecal matter and excrete about 10kg of faecal matter per day. Similarly, evidence chat Cryptosporidium loss rates in large fresh water dams/lagoons where sunlight can penetrate is in the order of 0.01 to 0.02 log/day . The mass balance model generates a design value worst-case Cryptosporidium oocyst concentration. Consequently, it is felt a target after treatment of 0 .002 oocysts/1 (Nadebaum 2000) und er such a worst case co ndition is a mo re reasonabl e target than the more stringent average target adopted by the USEP A of one extra infection / 10000 people each year or abo u t 0.000035 oocysts/1 (Nadebaum 1998) . That is, the probability d istribution fo r Cryptosporidium concentration in water is usually highly skewed (H utton, 1995). Figure 2 illustrates the setup fo r the mass balance model including nonpoint sources (e.g. rural residential w ith septic tanks area) and po int sources (e.g. cattle grazing along reservoir shoreline) for an inhabited catchment with a single large storage which stratifies in summer and experiences large summer storm even ts. Formal Quantitative Risk Assessment (QRA)

Application of the QRA approach to establish risk costs for flooding and dam failure analysis is becoming feasible in risk assessment for drinking water quality. Hass (1983) and others have used dose response and water consumption co define w hat constitutes a low risk Cryptosporidium concentration. Croso (2003) and others have assessed economic consequences fo r 52

WATER FEBRUARY 2004

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water borne epidem ic events. However, little work is published on comparison of options for improvement based on considering poor water quality events in terms of numerical frequency of occurrence from catchment and dam sources and dollar values for the consequential impact of the resulta nt poor water quali ty at customer taps. A QRA was developed for a large system providing drinking water to some 340,000 customers. A bushfire burned o ut most of the m ain catchment area. The supply is cold, unfiltered and disinfected using chlorine . Typically prior co the bushfire the turbidity at the chlorinator was <2NTU and after chlorination the levels of coliforms/ E-coli complied with Australian Drinking Water Guidelines. Since the bushfire event physical-chemical water q uality deteriorated substantially in the main raw water reservoir (e.g. manganese, iron, turbidi ty,

(Eg. Energy, Sewage Sludge)

colo ur and colifo rms) especially following storm events. An alternative filtered water supply of limited capacity and yield is ava ilabl e but its use alone in sum mer would mean that severe water restrictions would have to be imposed. Also, failure co us e the unfiltered sou r ce in Winter/Spring would result in spilli ng of the unfiltered supply storage dam and excessive lowering of the dam supplying the fi ltration plant resu lting in an unacceptable risk of running ou t of water if a long drough t event then occurs. The workshopped seeps for chis QRA consisted of: • Definition and agreement on treatment op tions to be assessed. • A qualitative risk assessment of the current catchment to tap system co understand details of system operation options and hazards likely co be high risk and w hy.

Residual Env. Costs

ORA RISK COSTS

(Eg. Illness, Copper, THM's, Cancer) (Eg. Homa Fitters, Tourism Loss, Staining, Industry Treatment)

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Distribution fo r Total Option 2 Risk Cost/A048 1

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• Agreem ent on the o verall water supply system arrangement and how it would be managed for each opti on . • Agreement on the important "events " of poor water quality that could arise at the outlet of th e raw water supply reservoir and th e likelihood of occurrence at this point. • Defini tion of event trees and likelihoods for various circu mstances downstream of th e reservoir o utlet poin t w hich would reduce th e likelihood of each pollution "event" reach in g custom er taps. T he consequences expec ted were also defi ned (e.g. c oli fo rm non-co mpliance, high turbidity) as we ll as t he expe ct ed corrective actions (e.g . iss uing of a boil water notice, responding to custom er com plaints, hospitalisatio n /visit to GP). • D e finition of the expected so cial, fina ncial and operatio nal /e nvironmental risk costs asso ciated with each poor water q u ality eve n t that ge ts th ro u gh t o customer taps and th e possible probability distribution fo r each cost based on uncertainty and the skew (e .g. is it likely to be a higher or a lowe r cost) . • M o nce C arlo m odelling fo r each o f th ese risk co st el em ents to establish the ran ge in exp ected cost impacts for all the poo r water eve nts wh ich co uld reach custo m er taps fo r each treatm ent option . • Rep eat of the above steps fo r th e alternative imp rovem ent options. Eac h event tree consisted of a number of circumstan ces each w ith a likeliho o d of occurrence. The abili ty to minimise th e likeli h ood o f a poor wa ter quality event reaching custo mer taps depended on factors such as: • Size of demand fo r water at th e time . • Intensity of poo r wa ter quality eve nt a nd w h e th e r it was detecte d by mo n itori ng.

• W heth er the other filtered water source cou ld be used . • Whether existing treatm ent (disinfection) at the unfiltered source was effective. A simplified example event tree is presented in Figure 3 for tu rbidity. T his tree shows that for every high turbidity event occurring at th e raw water reservoir

outl et circumstances within the water supply system at th e time the pollution event o ccurs (e.g. level of de mand and abi lity to stop using this source) should m ean that only about l event in every 37 would go through to custom er taps with the co nsequ ences of a boil water notice being issued. C onsequently because in any year about 8 events are likely then th e

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chance of an event going through to customers and ca using a boil water notice would be about 1 event in every 4 to 5 years. The risk cost assessment revealed the largest potential co st impacts would occur for: • Tourism, in response to "do not use water" press release if blue green algae toxins reach a high risk level. • A water borne ill ness epidemic event. • A " boil water" press release in response to microbiological noncompliance. • Short term demand restrictions in response to the need to stop using the unfiltered sou rce. • Increased use of the expensive filtered supply. • In addition to ri sk costs normal operation and annualised new capital costs must be added to provide a fa ir comparison between options (see Figure 4). An illustration of one of the risk cost distributions and annualised total cost outcome for the three options considered in this study is shown in Figure 5. Th e

three options were status quo (option 1), filter all the water (op tion 2) and a smaller filtration plant with blending of raw and filtered water in summer (option 3) .

Conclusions Risk assessments are progressively being completed in water utilities in Australia and New Zealand. Initially qualitative risk assessments should be completed using a relatively simple methodology outlined in AS/ NZS 4360. A workshop approach with water utility representatives is essential to draw out the experience with poor water quality events, and to understand how the water supply system really works from catchm ent to customer taps. Only then can the water quality risks be effectively identified and prioritised in qualitative terms. Once this process is complete it is feasible to provide a more quantitative pictu re of particular high risk issues, such as Cryptosporidi11111, algae blooms and sto rm generated poor water quality events particu larly when co mparing improvemen t options. Semi- quantitative mass balances for Cryptosporidi1m1 are

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feasible using results of recent research on loads from various animal and hu man sou rces and transpo rt loss in rivers and dams, then filtration. Th e main outcome is whether existing barriers are sufficient for a low risk of water borne illness in water delivered to custom er taps. Similarly QRAs for both health and aesthetic con tamination events usin g estimates of likelihood and th e social, economic, operational and environmental risk costs can p rovide guidance on total costs for va ri ous wate r quality ni.anage ment options . Working within the accuracy of the available data and using assumptions supported by good science is essential for credible results.

Acknowledgements T his work uses work developed in an earlier DPIE project with Melbourne Water and in CRC Water Quality and Treatment projects as well as risk projects with a number of water authorities. The contributions of the many people involved is gratefully acknowledged.

The Authors Mike Chapman is Manager Water Quality; Dr Peter Nadebaum is Senior Principal; Greg Finlayson is Manager Water Treatment, all at GHD Pty Ltd, Melbourn e, Australia; and Steve Carne is Manager Water Industry , GHD Ltd, Auckland, New Zea land. Emai l Michael_c hapman@ghd. com.au

References Ca rne S and Chapman M (2002), Public H ealth risk management plans- Integration into a Councils existing Q uality Management Framework, NZWW A Annual Conference 2002 Coros P, Kramer M et al (2003) Cost of illness in the 1993 Water Bo rne Cryprosporidi11111 outbreak, Milwaukee , E111e1gi11g I,ifecrio11s Diseases, April 2003 Vol 9 p426 Hass CN (1983) estimatio n of risk due to low doses of microorganisms: a comparison of alternative methodologies Americm1 j ,m,·,ia/ of Epidemiology 118: 573- 582 H utton P et al (1 995), Cryptosporidi11111 and Ciardia in the Aquatic E nvironment of Sydney, Australia, Protozoan Parasites and Water (W Betts et al editors), Roya l Society of Chemistry Cambridge, England Nadebaum P er al (2000), Cryprosporidiw11 and Cm11pylobacrer in Drinking Water Supplies, Part 2 : Estimating the Incidence oflnfection and Illness, Water Jo,mia/, Australian Water Association , May/June 2000 Nadebaum P, Chapman M , Stevens, M (1998) Treatment Requirements for Australian waters. Internal Melbourne Water/ Dept of Primary Industry and Energy R eport Scharfenaker M (2002),JAWWA, R eg Watch, Feb 2002.

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