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Volume 24 No 1 May/June 1997 Journa l Au st ra lia n Wat er & Wast!;)water Association

CONTENTS

Editorial Board F R Bishop , Chairm an B N Anderson, G Cawston, M R Chapman P Draayers, W J Dulfer, GA Holder M Muntisov, P Nadebaum, J D Parker A J Priestley, J Ris man

~dvertislng & Administration A WWA Federal Office General Editor: Margaret M etz Advertising: Lynne Mathias PO Box 388 Artarmon NSW 2064 Level 2, 44 Hampden Road, Artannon Tel (02) 9413 1288 Fax (02) 9413 1047 Email: awwa@abol.net

Features Editor EA (Bob) Swinton 4 Pleasant View Cres, Glen Waverley Vic 3150 Tel/Fax (03) 9560 4752

Branch Correspondents ACT - Ian Bergman Tel (06) 248 3133 Fax (06) 248 3806 New South Wales - Mitchell Laginestra Tel (02) 9412 9974 Fax (02) 9412 9676 Northern Territory - Bill Bean Tel (08) 8924 7201 Fax (08) 8941 0703 Queensland -Tom Belgrave Tel (07) 3810 7967 Fax (07) 3810 7964 South Australia - Peter Martin Tel (08) 8303 8723 Fax (08) 8303 8750 Tasm ania - Ed Kleywegt Tel (036) 238 2841 Fax (036) 234 7109 Victoria - Mike Muntisov Tel (03) 9600 1100 Fax (03) 9600 1300 Western Australia - Jane Oliver Tel (09) 420 2462 Fax (09) 420 3178

Water (ISSN 0310 ¡ 0367) is published six times per year: January, March, May. Ju ly, September, November by

Australian Water & Wastewater Inc . ARBN 054 253 066

Federal President Mark P asco e

Executive Director Chris D avis Australian Water & Wastewater Association assumes no responsibility for opinions or statements of facts expressed by contributors or advertisers and editorials do not necessarily represent the official policy of the organisation . Display and classifi ed advertisements are included as an informational service to readers and are reviewed by the Editor before publication to ensure their relevan ce to the water environment and to the objectives of the Association. All material in Water is copyright and should not be reproduced wholly or in part without the written permission of the Editor.

Subscriptions Water is sent to all members of AWWA as one of the privileges of membership. Non-members can obtain Water on subscription at an annual subscription rate of 39 (surface mail).

From the Federal President .... .. ....... ... ... ..... .......... ... ..................... ................ .. .... .. .. ........ ... ... 2 From the Executive Director ...................................................................................... ......... 4

MY

POINT

OF

VIEW

Client-Based Universities? ... .... ... ...... ....... ... ................... .. ... ..... ................... .... .... ..... .. ... .... . 3 J Imberger Water a nd the Institution of Engineers ....... ................... ... ... ......... ... ....... .. ... .. ... ... ... .... ........ 7 TLoos

WATER Domestic Non-Potable Reus-Why Even Consider It? ... .... ... ... .......... .. . ... ... ... ... ... ... ... . ... 9 I B Law Drinking Water and Public Health ..... .... ................... . .... ............ .... ... ........ ...... 14 M Muntisov Top End Awash .... ... .... ......... . ............ ................. .. ............ ......... ... 15 B B ea n Setting Public Health Priorities In Drinking Water Quality and Treatment .. ... ........ ...... . 16 RM Douglas Aluminium In a Water Supply . .... .... ... ..... .............. ... ....................... .... ... ... ... ... ....... .... ..... . 18 BA Collier, ] Lin

FEDERAL

CONVENTION

Water In the Balance-AWWA 17th Federal Convention .... .... ... ... .. ... ..... ... .... .............. . EA (Bob) Swinton The Keynote Addresses .... ... ... .. ... ....... ... .. ....... .. ... ............................ ... ...... .... ..... ... .. . EA (Bob) Swinton Behind the Magic, Behind the Red Shoes, Behind the Scenes ...... ... ... .... .. .. M M etz The Team Behind the Scenes MMetz Impressions of the Technical Sessions ........... ............ ..... ............... ................. .. EA (Bob) Swinton

24

25 28 35 31

BUSINESS Performance Management- The Key to Organisation Effectiveness .. .. .. .. ...... ............. 40 P R enfrew

ENVIRONMENT Deve lopment of Australia's New Horizons Oceans Polley .... .... ... ... .... .. .... .. ... MM etz CDS- A New Screening Technology for the Environment ... ... .. . ... .. ... .. ..... .. ... .. .. RA J ago National Waste Industry Meets at Waste TECH Conference .. ... ....... ... ... . ... ... ... ... ... .. ... ... . P Nadebaum Attenuation of Landfill Discharges In Sandstone Streams .. . . ... ..... ... .. ... ... ... ... .... ... ... .... M Petrozzi

45 47 51 53

WASTEWATER Innovation In Sewage Treatment Tokyo Style ... ..... ... ... .. . .. ... ... ... ... .... ... ... .. . ... ... ..... ... ... 54 P Gross Dewaterablllty of Activated Blosollds .. .. ... ............ ...... ............... ........ ............ ...... .. .... .... 56 I H Bane The IDEA Plant at Black Rock, Geelong ... ........ .. ................................. .. ... .. ... ... ... ....... .... .. 59 G CH Williams

DEPARTMENTS International Affiliates .. .... ... ... ... ... ... ... ... ... ... ... ... ... ... .. ... .... ... .. ..... . ... ... ... ... ... ... .. ...... ... ... .. ... 5 From the Bottom of the Well ... .... ... ....... . ... ... ... ... ... .. ... ... ... ... .... ... ....... .. ... ... ... ... ... ..... .. .... ... . 2 Meetings ........................ ... .. ... ... .. ... ..... . .............. ..... ... ... ... .... ...... ....... .... ..... .......... .. ... ........ 64 OUR COVER : Three-dimensional roll-wave instabilities on the spillway of the Wellington Dn111 near Collie,

MIA. This dam is the main source of irrigation waterfor SW WA and is the site of 111a11y early experiments on physical li111110/ogy carried 011t by the Centre for Water R esea rch. Photo co urtesy of P rof]. Imb erger.


FROM

THE

PRESIDENT

Teamwork Rules OK! The task of turning around river degradation , salination, water allocation and all the other water problem ~ which face Australia is a H erculean one. Not only do w e have to improve our imperfect understanding and find the wherewithal to fund the expenditures involved, but we need to refine our decisionmaking processes.

Lobbying Power G rea t lobbying power resides with the v es t e d int e r es t s on on e h a nddevelopers, agriculture and industries which count on expansion , anywhere. On the other hand, the green agenda is important. Politicians feel the need to take an environmentally fri endly line, but they are not necessarily always advised in the most rational fas hion . While we have to face up nationally to some serious issues and some major expenditure, it will be vital that the decisions are made on the basis of the best possible scientific and economic advice, not intuition o r popular concerns. AWWA, low key as it always has been , finds it difficult to make more than a small impression in Canberra and at State government levels, so our ability to influ ence outcomes is seriously limited. W e need to work in collaboration with sister organisations so that our collective position carries eno ugh weight to make a difference.

Strategic Alliances As w e are a broad- in fa ct, the broadest-water interest group m Australia, our m embers' views are equally diverse. To make an impact in particular spheres w e need to align ourselves with specialist groups which have both the knowledge and affini ty with that area to add their support to our opinions. In th e environment sphere, for example, our own policies align well with those of the ACF (the last Peter Hughes W ater Award winner was Tim Fisher, ACF's water campaigner), so we could do worse than to keep comparing notes, as we have done for a while, and to join forces where necessary. In irrigation, where nearly 80% of Australian water is used , the Irrigation Association, with 1,800 members, is the largest and best organised association. If w e develop j oint activities with them , 2

WATER MAY/ JUNE 1997

the result could be a cohesive view fro m a constituency w hich is seen to be large, inclusive of experts but also represen tative of the broad rump of organisatio n s and people genuinely concerned about water. A large constituency with w hom we need to share more is the Institution of Engineers, Australia w ho se (IEAust), m embership overlaps our own in the water area. In our early days there was a tacit arrangement that AWWA 'did' urban water supply and sewage, while IEAust ' did ' the res t-hyd rology, wa ter resources and so on. Since our major reorientation in 1987, though , AWWA has taken a much broader view of water. The last issue of W ater, for example, was devoted largely to hydrology. It makes no sense for two organisations to compete fo r the minds of common members, so dialogue will be stre ngthened . There are probably quite a few areas w here the private sector could make proposals to delive r solutio n s for problems w hich have been intractable under no rm al government financing arrangements. Our members include all shades of opinion on that sort of issue and AWWA should be fo stering the debate in an open fo rum, so that the competition of ideas can test the mettle of the optio ns. By the time this column goes to press there will have been some excellent papers on these areas delivered at the Federal Co nve ntion m M elbo urne.

Positive Outcomes As a medium-sized associatio n we realistically cannot expec t to carry considerable political clout, but we can work with others w hose values w e share and w hose expertise adds weight to our own , and vice versa. A range of well chosen alliances may deliver some of the outcom es that we all hope for. A case in point is the administration of the Environmental H eritage Trust, now that the partial sale of Telstra has been committed. Sen sible, large proj ec ts need to be assembled with the available funds. If we work with other stakeholders to espo use the principles and perhaps some likely proj ects, there is some hope of a good outcome. Mark Pascoe

From the Bottom of the Well Joh n O lsen wrote in January's Water that in South Australia they have 'transformed a domestically focussed monopoly into a largely internationallyprivate sector, focussed, export oriented industry.' A dramatic change of emphasis indeed. Over the last decade there have been significant, ongoing changes to the urban water authorities in other states too. It is perhaps timely to remind ourselves of where the old authorities put their priorities. They were service providers designed when clt!es needed to be drought-proofed and to have sewage removed from their streets. They saw themselves as being in the public health business, as managing the whole water cycle and as providing integrated water resource management services to their communities. They saw themselves as guarding public health, protecting water quality through an elaborate system of barriers and as stewards over the water supply and sewerage system. They believed the viability of their cities depended on them. What might these institutions become in the future? They will be smaller, commerci;illy oriented and perhaps fragmented. They may buy bulk water from a head works authority or water factory mining the sewer or treating raw water and retail the water at prices determined by a pricing authority. Wastewater could be collected by another authority and treated at a privately owned and operated treatment works before being reused or released to the environment under regulations set down by an environment protection agency. They will practise demand management. Their vision will be narrower and the big picture may be left to others to draw. Their focus will be on customers, market forces and financial considerations. They will be challenged by scarcity of resources and an environment under increasing stress, whi lst be ing tempted to maximise profits by incurring risk. By making changes to the water authorities we are making gains. But do we know w hat we are losing? We need to define our objectives in terms of desired economic, social and environmental outcomes. Are we doing this? Are the guardians and protectors still on duty? Do we know who they are? In the same issue of Water both John Langford and Chris Davis called for 'a vigorou s and informed debate on the way water services are to be delivered.' We should listen to them. Freddo


MY

POINT

OF

VIEW

CLIENT-BASED UNIVERSITIES? Professor Jorg lmberger Jorg Imberger is Professor of Environmental Engineering at the Un iversity of Western Australia. His interests are in the motion and mixing of stratified fluids such as are found in lakes, estuaries and coastal seas, and their ecological significance. He is a Fellow of two Nationa l Academies, and recipient of the Onassis Prize for the Environment and the 1996 Stockholm Water Prize.

Ten Years of Change Australian universities have undergone dramatic changes in the last ten initiated by the Labor years, Governmen t and furthered by the present government. These changes in clude an ever-increasing proliferation of universities, a zealous attempt to quantify accountability, a strong push for affirmative action and a conscious attempt to improve efficiencies through unifying the system. The main vehicles have been a withdrawal of 'unaccountable' money to be returned in a directed way and a push towards a user-pay system. These changes mostly sprang from the frustration that the university system, while doing a relatively good job at education, was not providing a tangible return to society. The government, then and now, felt that universities , and to a lesser extent the CS IRO , existed in isolation and that Australian industry was not benefiting from Australian intellectual property which was either lost or syphoned off by overseas companies w hich then reaped the profit. The sh ort answer was to make academics more relevant to industry, i.e. make them compete for industry involvement, put research money into industry/university partnerships in CRCs and direct the universiti es to become relevant , accountable and ensure they have quality assurance programs in place. (In order to achieve this we obviously needed to have as many reviews as possible!)

A Success? Well , has this major initiative been a success? Is society now benefiting from universities more than it did before? Is the education of graduates better? H as the level of our international standing in intellectual creativity improved? There are many indicators, but in broad terms few would argue about two generalisations. On the positive side, by

increasing the focus of existing intellectual activity to applications which could yield co ncrete returns to Australia there has been a significant increase in the transfer of intellectual property to the commercial sector. On the other hand, thi s transfer was brought about to the detriment of long-term fundame ntal intellectual activity. T he irony is that, at least to my knowledge, there is little evidence that industry has seized on this opportunity and converted these intellectual advances into taxable reve nue. Australian industry has not moved one centimetre closer to the idea that profitability, in the long run, will be achieved through increasing the level of technical and sociological sophistication. Australian industry still seems to see increased profitability being achieved almost exclusively through improved financial restructuring. In the case of the water industry, it has been too preoccupied with restructuring and privatisation to be concerned about capitalisation on intellectual property transfers. We have ended up with a university system w hich is rapidly exhausting its long-term intellectual creativity, a system which forces students through more practical courses, and yet our intellectual property is still not applied.

A Client-Provider Incentive The problems came abo ut and still exist because Australian universities , apart from the traditional student education program, do not have clients. If we want universities to perform the additional function of providing intellectual property to Australian society, then we must provide an incentive mechanism. First, fundamental research must be supported by the government, w ho should see it as long-term venture capital. Australian industry is simply not mature enough to be a client for fundamental research. T he ARC must be free of all industry and government directives and funding sho uld be substantially increased. The old ARGS was a much better model. Funding was decided by a panel of the best

researchers in the coun try and accountability was achieved by peer review of the proposal. Second, a simple industry incentive scheme should be introduced to replace the CRC system and all similar directed funding systems (and there are many). This money should be pooled and givent to those researchers who attract money from society, so called 'outside money' o n a dollar for dollar basis (or an x% per dollar) . Expenditure of this money should be at the discretion of the researcher. Those researchers who are actively collaborating with industry or the wider society would attract the subsidy and the government's contribution would automatically go into areas which are relevant to Australia. T hird, government support for the educational component of universities should be again simply tied to the benefit as perceived by the society. A simple parameter could be the cumulative starting salary of all the students graduating from a university measured say, by June of the following year. This would au tomatically foc us the university's output to those skills w hich are sought after by the market. If people cannot get a job we should not be educating more of the same. These three sugges tions would produce exactly the result everyone is trying to achieve; an environment which breeds curiosity, creativity and enterprise in areas which are needed by Australia. In addition, the cost savings achieved by abolishing the huge bureaucracy set up in the name of accountability would be considerable. WATER MAY/ JUNE 1997

3


FROM

THE

EXECUTIVE

DIRECTOR

More Bang per Buck Now that the partial sale of T elstra has b ee n approved and th e D emo cra ts are urging that the fund s be used quickly and effectively for the benefit of the we environment, need to add o ur voices to the chorus. Of co urse, the nature of Canberra is that there will be a long queu e o utside the doo r of eve ry bureaucrat entrusted with the alloca tion of funds from the Environm ental Trust. In the strange world of our capital, handing out funds is a guarantee of popularity and stature. The risk here is that the funds may well be carved up so thinly in order to keep a maximum of constituencies happy that each slice will be so small as to be ineffectual, both in terms of to tal grunt and in terms of the economies of scale involved in getting things done.

South-East Asian Impressions

Although AWW A supports the initi atives o utlined, we do not have sufficient clout on our own to make a big impression in Ca nberra. In another column in this issue of Water though , AWW A president Mark Pascoe advoca tes aligning ourselves with likeminded associations to achieve greater leverage. That is an excellent concept and it could m ean that Blackmore's vision becomes a reality. Let's work together.

In March I made my first visit to Manila , the teeming capital of The Philippines, to mee t with leadership from six other South-East Asian wa ter and environment associations under the banner of the W ater E nvironment Federation (WEF). Each of the associations either is or soon will be a member ofWE F and we met to compare notes, plan fo r the first WEFTEC Asia conference and exhibition in Singapore (8-11 March 1998) and to discuss how we might collaborate in future. . W e have a lot in common with colleagues in the region and should keep much more closely in touch with them , especially for those of o ur members w ho are active in South-East Asia. The local knowledge and nou s available in each country is invaluable for someone moving into that market. Apart from the WEF meetings and a technical seminar set up to share ideas from the region, we had an opportunity to see the city w hose wa ter and sewerage will now be supplied by the two winning consortia w ho won the bid earlier this year. Something like 60% of the water supply in Manila is unaccounted for and only about 10% of the metropolitan area is sewered , so the contractors face huge challenges. W e also took a ferry ride up and down the Pasig River, M anila's equivalent of the Parramatta River, but w hich is m a m u ch poorer co nditio n. Although industries along the river are being brought under control, there are probably a million people literally living on the river banks, dumping most of their garbage and sewage straight into the wa ter. This could be described as the mother of all diffuse sources, and I canno t imagine just how that will be tackled. There is a Pasig Rive r Rehabilitation Proj ect under way now, with the ambition of making the river habitable for fish within about 15 years . This presents an immense challenge and I imagine many Australian companies will be aiming to lend their expertise to solving the multitude of problem s involved. Chris Davis

New Members

Victoria

Western Australia

ACT

Michael Ell is, S Pearce-Higgins, Phil li p Ridgeway

PS Armanasco, BJ Loffler, C J Hu, R G

Christi na Jackson

Queensland

Kurup

NSW

Michael Burridge, Sandra Burke, Karen Ch ri st ians, Ri chard Dimmock, C F Novosad , Tania L Prins, M J Ro llo, K Sylow

Tasmania

Funding for Selected Projects Don Blackmore, C hief Executive of the Murray Darling Basin Commission, has made a plea for selec ted river basin proj ects to be well funded, so that the prospec ts of 'changing the .landscape' and having a real impact on n ver health can be assessed. T his sort of proj ect necessitates a w hole of catchment or river basin approac h to agriculture, forestry, landu se, riparian vege tation and soil management. It is an excellent idea and should be supported to the hilt. Obviously, there is a downside, since there will be winners and losers, with some areas and age ncies winning large proj ec ts and others getting nothing. That is a reality w hich commercial organisations face permanently, so it should no t be seen as unusual. On the positive side, the possibility of demonstrating the potential to reverse river damage and even salinisation is an exciting one. As Blackmore said in a speech to three newly merged CS IRO divisions , now called Land and

Pau l Casamento, Susa n Dai , Andrew Draper, Emma Ham ilton, CW Jenkins, Bill Low, Anthony Martin, Sharon Murphy, Graham Turn er, Catherine Stokes

4

Water, eve n a nega tive result provides priceless feedback about how to tackle problems 111 o ur natural resources. Au stralia alrea dy has a growing reputation fo r being one of the few nations that is really grappling with ca tchment and river ba sin managem ent. T he abili ty to mo unt serious projects in that sph ere has the potential to cem ent that reputation and enhance it. Let's do it.

WATER MAY/ JUNE 1997

Water Quality Management Strategy A ve1y useful tool wi th w hich to tackle river management is the National Water Quality Management Strategy, many of w hose guidelines are now published. Althou gh this strategy is primarily aimed at wa ter quality and communi ty aspirations for water uses , the principles of su stainable use, consultative goal setting and then denving local standards to ac hi eve those goals are applicable in principle .to all natural reso urce management se ttmgs. T eams of experts have laboured fo r five years co prepare the National Water Quality Management Strategy . M ore than a dozen reports represent scientific and technical con sensu s on how to manage water quality in the long term. It wo uld be a tragedy if we did not implement them . Let's use them .

Increased Leverage Needed

Fleur E Yax ley

South Australia

Overseas

Robert Hall , NA Howarth , Sara h Murphy

Teraz Herson , Sli m Zeghal


WATER

WATER AND THE INSTITUTION OF ENGINEERS T Loos The current presidents of two major national bodi es ju st happen to be Queenslanders and just happen to work in offices two hundred metres apart from each other at Milton in Brisbane. Dr Tom Connor, the national Presid ent of the Institution of Engineers Australia (IEAust) and our own national President, Mark Pascoe, took advantage of this situation recently to m eet over lunch 111 nearby trendy Park Road to discuss differences and similaritie s betwee n the two organisations. Also present were Rod Lehmann , Steve Posselt and I. (Well, someone had to w rite the story and take the photo! )

Roles of the Two Presidents Both presidents are well into their terms in office. M ark's two-year term fini shes in November 1997, w hile Tom's one-year term ends on 1 May 1997 at the IEAust national conference in P erth , w hich incidentally ha s a watery theme, Catching the Tide ... ef the Indian Ocean Rim. With 65,000 members compared to our 3,7 00 , Tom is the president of a m uch larger organisation that also has a larger membership fee of $300 compared to our $75. Tom spends about fifty per cent of his time on IEAust business away from Brisbane and therefore feels that a twoyear term for IEAust President is unaffordable. H e w ill , however, be somewhat more frustrated than relieved when his time is up - there is so much unfinished business! Mark considers his role his 'night-time' job , but admits that it do es take up som e of his 'daytime' as well. It seems that neither organisation has created a m eaningful role for their past presidents w ho wish to stay actively involved. What do yo u do with past leaders? Do their views matter? Should they be allowed on ABC TV? The president ofIEAust is elected by its Council of 42 m embers w hich meets three times a yea¡r. Just imagine chairing a m ee ting! Their more frequent Board of M anagement meeting has overcome the problem of meetings obsessed with debate over detail and process at the expense of policy. Their solution is to have free-wheeling 'issues mee tings'

IE Aust and AWWA Presidents, Dr Tom Connor and Mark Pascoe in Brisbane

where no notes are taken except that one person is responsible for documenting the concluding decisions that are made.This initiative is also now reflected in similar forums of the 42member Council meetings.

Opportunities for Joint Ventures R ecently the Australian Academy of Technical Sciences approached IEAust with a proposal to jointly develop a $400,000 strategy for water resource development and management . The basis for the idea is that the extended period of drought that Australia has experienced has made governments and the communi ty acutely aware of issues such as wa ter development , use, resea rch , agency support, data and the economic impact of water deficiencies. At the same time the organisational stru ctures and practices of the water indu stry have bee n significa ntly reformed . The proj ect would aim to identify 'where to from here ' for the indu stry . This seems to be the sort of proj ect Governments normally aim to drive-an example is the Queensland Government's Water Infras tru cture Task Force. The proj ect is likely to com e to fruition in the next few months and should be of great interest to all associations in the water industry. M ark described a joint exercise that AWW A is already undertaking with the W ater Services Association, Foresighting the Water Industry. AWWA's Executive Co mmittee plans to discu ss the possibility of AWWA input into the strategy at its next m eeting.

Similarities, Differences, Overlaps Both Presidents agreed that they don't see their two organisations as deliberate competitors., The current arrangement between the Water Panel of the Queensland Branch of IEAust and Queensland AWWA is a case in point. Both groups plan their monthly programs at the start of the year so that their subj ects do not clash and joint meetings can be organised. The Water Panel tends to fo cus on hydrologic and hydraulic subj ec ts in its separate m eetings and the joint meetings usually deal with water resource managem ent and water environmental subj ects. However, Tom pointed out that IEAust incorporates a numb er of technical National Societies on , for example, Military Engineering, Industrial Engineering and Underground Tunnelling. M embership of these societies is not res tricted to engineers. Such societies in som e instances h ave m erged with preexisting groupings. What would AWWA think if a proposal emerges to set up a National Society of Urban W ater Engineering as an IEAust Society? M ark pointed out that AWWA has established m emoranda of understanding w ith organisations such as the Stormwater Industry Associatrion (SIA) and the EMIAA. However, no matter how hard Queensland AWWA tries to service the water industry, it has had difficulty maintaining all the running on water issues, as was demonstrated by the em ergence of the SIA. WATER MAY/ JUNE 1997

7


WATER

Rod pointed out that surveys of AWW A's members and clients find that AWW A gen era lly provides a good information delivery service but has a poor profile in government matters. Tom pointed o u t that IEAu st is strong in its political presence due to its sheer size, and ability to resource specific activities. However, its appeal to 'wa ter m embers' can be dilu ted because of its diverse focus on all forms of engineering and its other roles in relation to the profession. AWW A has an advantage in that we can concentrate our efforts almost w holly on water issues .

Another area of much activity is in promoting the real images of engineers and engineering. Tom's view is that , unfor tunately, much of the public believe that because they remember their Year 12 classmates w ho went on to engineering as tho se w ho were good at maths, that engineers mu st spend all their days in office boxes solving mathematical problems. (What are the other characteri stics of" enginee rs? Brow n suits? Hush Puppies? Shorts and long socks?) Later this year, SBS TV, with IEAust input, will show a 13-episode series of enginee ring- rela ted programs, The Elegant Solut,:on. AWWA for its part has put money into a children's play on the water cycle, and recently p ubli shed J enifer Simpson's water quali ty book.

"B'-.)1 I

:l I:O~\

WEA~ ?,WwN

su1rsl!

Education and Public Profile of Engineers IEAu st spends a lot of effort on ensuri ng high standards of engineering IEAust education are m aintained . accredi ts engm ee nng courses and recently has bee n extemely bu sy rev1ew111g engmee nng edu ca tion because of the expan sion of universities and the increased number of courses on offer. IEAust members probably don't realise how much effort goes into this area, but surveys indicate that they value the maintenance of standards highly.

So What Might All This Mean? The two presidents agreed that there was much in what they had covered where further dialogue could lead to mutually productive solutions. At the time of w riting, AWW A's Executive Committee was planning to discuss '?7.'~,. ,., . .,. ._-further collaboration opportunities at its next meeting. Progress will be reported in Crosscurrent.

BNR3 CONFERENCE 1997 THEMES

CONFERENCE BRISBANE

Th is conference is a foca l point of Austra lian and International experts and practitioners in the field of Biological Nutrient Remova l ( BNR) , who wi ll co nvene t o discuss and share their know ledge. Disc ussion w ill in cl ude research, des ign, operat io ns and troublesh ooti ng of BNR plants c urrent and future . By December 1997, there will be 9 operational BNR plants w ithin 2 hours d rive o f Brisbane .

Topics to be covered during the conference include:

Keynote Speakers:

• Platform Papers • Poster Papers • Trade Displays

QUEENSLAND 30 Nov-4 Dec 1997 Australian Water& Wa stewater Association

• Prof. George Ekama, University of Cape Town , South Africa • Ken Lindrea, La Trobe University, Bendigo, Australi a

PAPE RS Where: Ve nue: When:

Brisbane , Austra lia Brisbane Convention Centre Sun 30 Nov-Thurs 4 Dec 1997

• l 08 Abstrac ts accepted • More than 30% of Abstracts from Internatio nal contributors

• Microbio logy • Modelling & Simulation: Tools for Design • Operational Experience • Biosolids Management • Retro fittin g • Alternative Methods & Stra tegies Delivered by:

Further Information: Australian Water and Wastewater Association Queensland Branch Office GPO Box 2847 Brisbane Qld 400 1 Austra lia Telephone: +6 1 7 32 11 3692 Facsimile : +61 7 3211 3698 http ://www. c heque. uq .edu .au/ awm/ bnr3

MAJOR SPONSORS ~

an1~ Kruger 8

WATER MAY/ JUNE 1997

""' JOHN WILSON & PARTNERS


WATER Abstract

DOMESTIC

As interest in the reuse of reclaimed wa ter in Au stralia grows and more adva nced form s of reuse are implem ented , such as the domestic non-potable sys tem (or dual wa ter system) at R o use Hill, attention sho uld also be given to the added benefits, particularly in the areas of publi c health and environmental impacts, that co uld accrue if reclamatio n for potable re use were to be practised. T hi s article addresses the issues of cos t, publi c health , environmental impacts and commu nity accep tance that are often put forwa rd as reasons w hy the potable reuse route should not be considered at all. It concludes that these concerns have no substance and that potable reuse should be considered in the future as a m eans of not only prolonging the capacity of our fres h water supplies but also as a means of improving the water quali ty in our watercourses. Inconsistencies that exist in the interpretation of water quality guidelines and/or regulations are identified and suggestions are made for a more coordinated approach to the management of Australia's water infrastructure.

NON-POTABLE

sioned 111 late 1994 and provides reclaimed water to a nearby residential area in the north-wes t of Sydney (Law, 1996) . T his plant was designed to meet th e reclaimed wa ter quality requirem ents of the NSW G uidelines for Urban and Residential Use of Reclaimed Water (NSWRws=c l.11993). Reclaimed Water Quality Considerations. T he 1993

N ew South W ales Guidelines (NSWRWCC , 1993), w hich were the first set of quali ty limi ts introduced in Australia for domestic non-potable reuse, identify not only the required reclaimed wa ter quality, but also the technology considered capable of producing this quality-an approa ch similar to that taken in California and Florida in the US , w here co nsiderable attentio n was given to treatm ent trains that will effectively remove viruses and bacteria . T he NSW Guidelines are similar to the State of California Title 22 R egulations (S tate of California, 1978), with the exception that levels are specified in the NSW Guidelines for viru ses and parasites. In M ay 1995, a document that forms a part of the National W ater Quali ty M anagem ent Strategy, Guidelin es for the U se of Reclaimed Water, was tabled in draft form for comment. T hi s doc ument identified acceptable quality limits for a range of reuse alternatives including domestic non-potable reuse, groundwa ter recharge and indirec t potable reuse. All three quali ty standards are based on tertiary treatment of 'good quality' secondary efflu ent, but there is no specification for th e ac tual quality of this seconda ry effluent. There is no requirement for low levels of nitrogen or phosphorus, no level for salinity or sodium and no controls to minimise adverse impacts on groundwater quality or soil structures through long-term irrigation. It should also be noted that neither the Draft National Guidelines nor the Califo rnian T itle 22 requireme nts include any virus or parasite limits, although steps are now being taken in California to evaluate the presence of the pathogenic protozoa in reclaim ed waters (Rose et al. , 1995)-no doubt du e to the 1993 o utb reak of Cryptosporidiosis in Milwaukee, Wi scon sin , the fac t that ba cterial indicators are not representative of the occurrence of viru ses/protozoa w hen chlorin e is the disinfecting agent and the fac t that with domestic non-po table

WHY EVEN CONSIDER IT ?

Key Words Domestic non-potable reuse, potable reuse, trea tment technologies, environmental impacts, health impacts, Quantitative Risk Assessment, costs of reuse, community acceptance.

Introduction In A ustralia there is increasing pressure for reuse applications to move to the more advan ce d forms and considerable interest in domestic nonpotable reuse, or the 'dual water supply system.' Potable reuse, either indirect or direct, is talked about and there are studies being undertaken in various parts of the country into its application, but there appea rs to be little hard support for such schemes. With recent developments in the area of treatment technologies, quantitative risk assessment , managem ent pro ce dures and publi shed full- scale experience, there are many reasons w hy we should now move on from the dual water system s and seriously consider and plan for the implem entation of potable re u se . These include costs , environmental impacts and community health considerations. There are some questions that need

I B Law

Ian Law was a recip ient of the Mic hae l Flynn Award for t his paper in the Tota l Urban Water: Wastewater Products Management stream of AWWA's 17th Federa l Convention Proceedings

to be asked, and answered, if we are to m ove ahead in a responsible way . It is considered absolutely necessary for this next step in the development of Australia's water infrastructure to be taken in a fully coordinated and integrated manner, involving not only the R egulators, Planners, Practitioners and Politicians, but also the community at large.

Reclamation for Domestic Non-potable Reuse Domesti c non-potable re use schemes are being installed 111 New South Wales (e.g. Rou se Hill and W agga Wagga) and are being considered in other Australian cities including M elbourne, Adelaide and P erth. N umero us studi es have b een conducted in to their use on a dece ntralised basis, but to date there is no full- scale decentrali sed installation that provides reclaimed water for the full range of domestic non-potable uses, including toilet flu shing. The first maj o r domestic nonpotable reuse scheme in Australia is that at Rou se Hill, w hich was commis-

WATER MAY/ JUNE 1997

9


WATER reuse, reclaimed water is introduced into residential backyards and into homes when this use includes toilet flushing. Cryptosporidium has become the most important new contaminant for control of drinking water in the US (Lisle and Rose, 1995) and steps are being taken in that country to base the treatment train for surface water treatment plants on the pathogen load in the raw water; noting that different treatment technologies and combinations thereof can produce different log removal rates for the protozoa (Gerba, 1996). Health Risks. The health risks associated with domestic non-potable reuse generally relate to the 'acute' . effects and are associated with the ingestion of pathogens from the reclaimed water-there are generally no longterm or 'chronic' impacts, as is the concern in potable reuse where microconcentrations of organic material must be considered. Of the multitude of pathogens present in wastewater, viruses and protozoa are of the most concern. Protozoa, particularly Cryptosporidium, are very resistant to disinfection by chlorine, the disinfection process included in the acceptable treatment train of both the NSW Guidelines and the Californian Title 22 Regulations. The Rouse Hill plant, at some 15% volumetric throughput, produces a secondary efiluent that has been shown to contain 200-300 Cryptosporidium oocysts and 2000-3000 Giardia cysts. The reclaimed water, after chlorination, generally complies with the <1 parasite/SOL guideline value, even though breakthrough of Cryptosporidium oocysts did occur at the filters when the latter were in backwash mode. Just how safe then from a public health perspective is the reclaimed water that complies with the quality requirements of the NSW Guidelines or, for that matter, with the Californian Title 22 Regulations ? There must be some concerns over health risks when domestic gardens or local playing fields are irrigated or toilets are flushed. The City of St Petersburg, Florida in the US , for example, requires consumers of its reclaimed water to sign a 'Hold Harmless Agreement' before they can draw on the reclaimed water supply (Law, 1994). A health risk assessment was commissioned in 1995 by the NSWRWCC to assess the public health risk of distributing the Rouse Hill reclaimed water under two different measures of exposure (Rose et al., 1995). The enterovirus and protozoa data from the Arizona and St Petersburg Florida plants were included in the data set-the latter being a more complete 10

WATER MAY/JUNE 1997

set-and the results showed that without disinfection (i.e. postfiltration), Giardia could result in annual infection rates of above the 1 in 104 level, which is a reference regarded by the US EPA as being indicative of acceptable risk in the consumption of potable water in the US. Post-disinfection (chlorination) infection rates were below this figure for the enteroviruses, Cryptosporidium and Giardia, with the results from the three plants. A comparison of the reclaimed water qualities is presented in Table 2, showing that although the health risks comply with the US EPA's acceptable level of 1 in 104, the waters from the two US plants still contained Giardia cysts and Cryptosporidium oocyst, in some cases at concentrations greater than the levels stipulated in the NSW Guidelines. How significant is this? Are the NSW Guidelines too restrictive? Should we have a statistical basis for

compliance? Is the US acceptable level of risk of 1 in 104 acceptable to the Australian Health Authorities, and more importantly, the Australian community?

Notes (a) Figures reported were taken from operational results from the Rouse Hill plant and the Rose et al. 1995 Report. The Rouse Hill values are Numbers/SOL, thos~ for St Petersburg are Numbers/l00L and those for Arizona are Numbers/40L. (b) The Rouse Hill plant includes a chemical clarification step ahead of the filters (c) Results when the filters were not backwashing. A study carried out in California into the risk of waterborne enteric virus infection to humans under four different exposure scenarios (foodcrop irrigation,

Table 1 Comparison of the Australian domestic non-potable quality requirements with t hose of the Californian Title 22 Regu lations Constituents

NSWRWCC Guideline Values

Draft National Guideline Va lues

California Title 22 Values (1978)

Faecal co liforms

<1 in 100 ml

<10 in 100 ml (thermoto lerant co liforms)

No value set

Coliforms

<10 in 100 ml (in 95% of samples)

No va lue set

Viruses

<2 in 50 l

No value set

Parasites

<1 in 50 l

No value set

No value set

Turbidity

<2 NTU (geometric mean)

<2 NTU (prior to disinfection

<5 NTU (in 95% of samp les)

<5 NTU

<2 NTU average during any 24hour period

Minimum res idual ch lorine

5 mg/l after 60 minutes

1 mg/l after 30 minutes

No value set

pH

6.5 - 8.0 (a ll owable range)

6.5 - 8.0

No value set

¡ <2.2 in 100 ml (median value for 7 days) No va lue set

<5 NTU (in 95% of samp les)

7.0 - 7.5 (desirab le range)

Table 2 Comparison of enterovirus and protozoa counts in reclaimed waters (al Treatment plant

Post-filtration

Post-<:lisinfection

Enterovirus Giardia Cryptosporidium Enterovirus Giardia Cryptosporidium Rouse Hi ll (b) St Petersburg Arizona

-

2 .5 4.4 5

3.1

-

<1(c) 4 2.3

ND 0.3 0.1

<1 1 2.8

<1 2 1.2

Table 3 Effect of cl imate on reduction in potable water use for different forms of reuse Location Alstonville Sydney Adelaide Cobar

Annual rainfa ll (mm)

Non-potable reuse (%)

Potable reuse(%)

1800 1200 585 410

26 41 35 34

94 '74 51 38

Notes: (a) Figures reported were taken from operational results from the Rouse Hill plant and the Rose et al. 1995 report. The Rouse Hill values are Numbers/50L, those for St Petersburg are Numbers/100L and those for Arizona are Numbers/40L (b) The Rouse Hill plant includes a chemical clarification step ahead of the filters (c) Results when the filters were not backwashing


WATER golf course irrigation , recreational nor do they include the reticulation ter quality being thoroughly assessed impoundments and groundwater within the property boundary and the before any non-potable reuse scheme is recharge) showed that groundwater necessary safeguards against cross- implemented. It is submitted that reclaiming for recharge and subsequent abstraction for connections. The cost of producing and distribut- potable reuse will obviate all these potable purposes posed the least risk, with predicted infection rates being 1 in ing the non-potable water has been environmental concerns. 1011 (Asano et al., 1992). Even if the shown to be $2. 50 to $3.00/kL in urban viral load was increased to some areas (Smyth, 1992). It could reduce in Reclamatlon for Potable Reuse 111 vu/ 100L, the level of risk was only 1 the inland areas of Australia where Reclamation for potable purpo ses in 108 (compared to the US acceptable garden water needs are higher. generally conjures up grave, but There has been a strong belief that misplaced , concerns over health issues, level of 1 in 104) . The greatest risk was attributed to swimming in recreational potable reuse will be far too expensive appropriate technologies , community impoundments (1 in 102) followed by to be considered as a viable option to acceptance and costs. 'Accepting that either reduce water demand or to this paper is comparing the domestic golf course irrigation (1 in 10). impacts resulting from non-potable reuse option with that of These risk assessments were all based reduce on contact with reclaimed water that discharges to the environment. This is potable reuse, the issue of cost has complied with the Californian Title 22 not true. It has been shown that imple- already been addressed . This section menting potable reuse would have been will therefore concentrate on the Regulations. -It is submitted that the application of comparable with the cost of the domes- remaining three issues that are often put the multibarrier approach to advanced tic non-potable reuse scheme at Rouse forward as reasons why potable reuse water treatment as well as the use of Hill (Law, 1993) and that in the long- should not be considered. membranes, without the benefit of term potable reuse is likely to be less than non-potable reuse groundwater storage, will produce costly Health Issues. Health issues may be reclaimed water that could be safely (Anderson, 1995). It is also noted that divided into 'acute' effects caused by the distributed for potable pathogenic organisms and longreuse-with public , term 'chronic' effects created by as effl.uent discharge requirements become more organic compounds present in health risk from enteroviruses and stringent, the difference between the quality for micro-concentrations, some of protozoa being far less which can be present in the raw than that resulting discharge and that for potable reuse will reduce, water and others that can be from domestic non- which in turn will reduce the cost ofpotable reiise.' formed during the treatment potable reuse. process- for example, the disinReduction In fection by-products and THMs Potable Water Demand. Domestic greater environmental benefits will that can be formed duriiig the disinfecnon-potable reuse that includes toilet accrue with the potable reuse alternative. tion stage in the plant. Recent developments in membrane flushing reduces the demand for fresh It is considered that the health issues potable water by 40% on an annual technology and a greater understanding relating to the pathogens have been basis. Seasonal fluctuations in the need of appropriate technologies will drive addressed above (Section 2.2), and in for the reclaimed water will mean that the cost of producing reclaimed water fact it would appear that there is less risk there may be occasions during the that is suitable for potable reuse down, of infection from pathogens in the summer months when there is inade- be it for indirect or direct purposes- potable reuse option. quate reclaimed water or, as is the case the incremental cost for treating a Given the increase in the use of at Rouse Hill , the demand will have to secondary quality eflluent to a potable synthetic chemicals in our society, the be met by topping up with potable quality reclaimed water could drop to increase in industrialisation and the water. In the wetter months there will some 54c/kL by the tum of the century, development of very powerful analytical be an increased flow to nearby water- making it very competitive with the tools, there is a justifiable concern over existing price of potable water the long-term health effects on courses. A greater saving in potable water use (MacCormick and Johnson, 1996). It consumers if potable reuse were to be would be expected if potable reuse were will also be noted that as effiuent practised. It has been reported that practised--and any reclaimed water that discharge requirements become more many of the microorganic compounds is discharged to the environment for stringent, the difference between the present in waters could have carcinoone reason or another in this case will be quality for discharge and that for potable genic properties and that, with our of a superior quality. It has been shown reuse will reduce, which in turn will improved analytical capability, we are potable reuse can more than double the reduce the costs of potable reuse. Such still identifying organic compounds that savings in fresh water, with this figure was the case at Rouse Hill. we previously did not know were Environmental Considerations. A present in our raw water supplies varying around the country and being dependent upon the local climatic data residential non-potable reuse project (Crook and Okun, 199 3) . The as shown in Table 3 (Anderson, 1995). was commenced at Shoalhaven, NSW increased use of bottled water and the Cost lmpllcatlons. The capital cost in 1989 and carried out for some 18 resurgence of concern for waterborne of domestic non-potable reuse schemes months under the auspices of the then infectious diseases could be testimony has been shown to be $2,000 to $5,000 Public Works Department. While there of a public becoming increasingly wary per property, the higher figure being were no adverse health effects observed, of the quality of their water supplies. attributable to retrofitting the third pipe the study did note that there was an Stander (1979) wrote nearJy 20 years distribution system (Law , 1995 and increase in soil nutrients and sodium ago that 'It can be unequivocally stated Anderson, 1995) . These costs only levels (Anderson, 1995). that situations reported on the It is necessary therefore for the incidence of microorganics in drinking cover the infrastructure required to provide the non-potable water pipe to environmental consequences of land water are largely due to an over-assessthe property boundary. They do not irrigation to be considered, with the ment of firstly, the capacity of selfinclude the additional treatment long-term effects on soil structure (due purification processes and of the role of required to meet the NSW Guidelines, to salinity and sodium) and groundwa- dilution of the water environment in WATER MAY/JUNE 1997

11


WATER degrading and di ssipating . these compounds and secondly, the adequacy of the physical chemical unit processes of conve ntional water purifica tion systems to remove compounds which are present in the raw water intake at micro-concentration levels.' T he same concern could be expressed over the presence of pathogens . T he corollary to this is that if treatment is improved at the wastewater trea tment plants, industrial wastes are co ntrolled (or diverted) and total ca tchment co ntrol pro cedures are implemented, then the quality of the receiving waters and hence the raw wa ter supplies to downstream water treatment plants must improve. There are now many examples of advanced water reclamation plants that reliably prod uce reclaimed water of a quality that is equal to or better than that of the local raw water supply or drinking water-San Diego (Oliveri et al. , 1995) , D enver (Rogers and Lauer, 1992) , Cape Tow n (Water R esearch Commission, 1990), Pretoria (Stander, 1979) and Windhoek (van der M erwe , 1996). Epidemiological studies carried out in Windhoek showed that 'within the limits of the epidemiological studies done, no adverse effects on health attributable to the consumption of reclaimed wa ter could be established' (Isaacson et al. , 1987). A very comprehensive Health Effects Study was carried out in San Diego, US and confirmed that the water from the reclamation plant was more than suitable as a water source for the city of San Diego in the future. A quantitative risk assessment was also carried out as a part of the San Diego H ealth Effects Study, indicating that there was no added chemical risk to the community if the reclaimed water was used as a raw water source . The water quality at Windhoek is measured against the WHO G uidelines, the Namibian Guideline for Class A water and the Rand W ater Guidelines. Water complying with the latter guidelines is predicted to have no health implications to a person consuming two litres of water per day over a 70-year period (van der M erwe and M enge , 1996). Why then do people say that even if reclaimed water is shown to comply with current drinking water regulations it is not necessarily safe to drink? It is a sad fact that many of our surface waters are showing signs of stress du e to increasing urban development and the practice of unplanned indirect potable reuse that is rife in many parts of our country. Do those people w ho are adamant that drinking water regulations cannot be applied to reclamation for potable reu se believe that these standards are relevant to the situation 12

WATER MAY/ JUNE 1997

w here a conventional water treatment plant draws its feed water from a relatively polluted so urce? H ard questions, but they must be debated and some sense must be instilled into the way we go about the planning and regulation of our wa ter supplies . It is sub mitted that advanced treatm ent at the end of the pipe, coupled with strict ca tchment co ntrol , is a responsible way to address the many areas where o ur surface waters, and indeed our groundwaters, are showing signs of stress. It also enables us to reduce our demand for fresh water supplies if it is recycled to the potable system, either indirectly or directly. Technology Issues. Much has been written about the technologies that have and can find application in a potable wa ter reclamation plant , be it for indirect or direct re use (Law, 1993 and 1994; van Leeuwen, 1994; van der M erwe and M enge, 1996; MacCormick and J ohnson , 1996). Suffice it to say that it is accepted prac tice to provide at least two 'safety barriers' for each of the contaminants of concern-1111croorganisms, intrac table organic co mpounds and inorganic compounds. Plant confi gura tions would generally include some of the following operating in sequence, with selection being based on the multi-barrier concep t, sidestream disposal and cost-effec tiveness: chemical clarification , filtration (sand or membranes), activated carbon adsorption, ozonation and disinfection. T he plant configurations that Sydney W ater Corporation has based its costings on for potable reuse could require adjustment in light of recent experien ce in Namibia and the US (Fink, 1996). Community Acceptance. T he following quote arose from the community consultation work undertaken in D enver, US w hen its demonstration potable water reclamation plant was in operation: 'The most significant finding is that the general population will accept wastewater reuse, even potable re use, in far greater numbers than our conventional professional wisdom has previously indicated (Lohman, 1987) .' Community participation in environmental initiatives is now very mu ch on the agenda in Au stralia . However, the community's specific attitude towards potable reuse has not really been tested- possibly as a result of a relu ctance on the part of those involved to consider it as an alterna tive to the wide range of effluent managem ent options that are gene rally canvassed at the community participation stage. The Friends of the Earth, in their 1994 report to the then W ater Board in Sydney took issue with the comments in a Board report that stated that 'The

di sadva ntage with any potable reuse plan will be the expense of the required treatment and the difficulty in achieving public acceptance.' Suggestions for a broade r community consultation program were suggested (Friends of the Earth , 1994). Work by the University of Queensland in 1991 in northern NSW and in Queensland showed that w hile some 19% of respo ndents to its survey would support potable reuse, a vas t majority (76%) wer hesitant and would require reassurance as to the con cept's viability and reliability (H amilton and Greenfield, 1991). This is one area that will require greater focus if we are to reali se the benefits of potable re use.

Where To From Here? It has been the author's expenence that there is little support for potable reuse (both planned indirect and direct) from the various H ealth Authorities in Australia. These Authorities advise the Environmental R egulators as to the suitability, from a public health point of view, of the quality of reclaimed water for the intended point of discharge-be it a ri ver , the ocea n , a raw water impoundment upstream of a conventional water treatment plant (in the case of indirect potable n;use) or direct into the potable water distribution system of a community (in the case of direct potable re use) . In the light of recent findings from numerous full- and pilot-scale facilities, many of which are presented in this paper, it becomes important for water industry practitioners to understand the reasoning behind the apparent reluctance of the H ealth Authorities in some States to accept planned potable reuse, in any form . Further, the rel uctance by some to accept that quali ty standards for potable wa ter should also apply to reclaimed water mu st be debated and a clear understanding reached as to the reasoning or rationale behind this reluctance.

Conclusion It is concluded that considerations for advanced forms of reuse of reclaimed water should not stop with the domestic non-potable or dual water supply system. It is suggested that potable reuse has a number of advantages over the non-potable alternative and as such should receive grea ter considera tion , now and in the future. T he article also identifi{)s a number of issues that should be addressed by the Au stralian H ealth Authorities o n a coordinated basis in order to ensure that the potable reuse alternative can be reali stically evaluated in all Australian States and T erritories.


WATER References Anderson, J M (1995) Water Conservation and R ecycling in A ustralia: Sce nari os for Sustainable Urban W ater use in the 21 st Centu ry Proc 16th Federal Convention of AWWA , Sydney, 389- 395. Asano , T , Leong, LY C , Rigby, M G & Sakaji , R H (1992) Evaluation of the Cali forn ia Wa stewate r R eclamatio n C riteria using En teric Virus Monito ring Data Wat . Sci. Tech. ,26 , 7 -8, 1513-1 524. Crook , J and Okun, D A (1993) Water R euse: Past, Prese nt and Future Paper presented at An nual Co nference and Expo sition , Am erican Water Works Association, San Antonio , T exas D enlay, J and Dowsett , B (1994) Water R e-Use: The Most R eliable Water Supply Available R eport prepared on behalf of Friends of the Earth (Sydney) Inc, Sydn ey Fink, W (1996) Planning for Potable R euse in Syd ney-Putting our Effiu ent where our M ouths are Watertech , AWWA, Sydney, 374- 380 Gerba , C P , Ro se, J B & Haas, C N (1996) Quantitative Microbiological Ri sk Assessm ent for R eclaimed W astewater Watertech , AWWA , Sydney, 25 4-260. H amilton , G and Greenfield , P (1991) Potable R euse of Treated Wastewater Proc 14th Federal Conve ntio n of AWWA, Perth , 497506. Isaacson, M , R auf Sayed, A & H attingh , W HJ (1987) Studies on H ealth Aspects of Water R eclamatio n during 1974 to 1983 in W indh oek , Namibia R eport prepared for the Water R esearch Commission by the South African Ins titute of M edi cal R esearch , Pretoria. Law, I B (1993) Potable R euse: Shou ld It Not Be Co nsid ered More Fully? Pro c 15t h Federal Conve nti o n of AWWA , Gold

Coast, 542-547. Law, I B (1994) Unplanned and Planned Potable R euse: There is a Diffe rence Proc 4th R ecycled Water Seminar , NSWRWC C/ AWWA, Newcastle, 74-82. Law, I B (1995) Non-Potable R euse System s Why Not Consider Planned Indirect Potable R euse Systems? Proc Northern Engineering Conference, IEAUST, M ackay. Law, I B (1996) Rou se Hill - Australia's First Full Scale Domestic Non-Potable R euse Appli cation Wat. Sci . T ech. , 33 , 10-11 , 7178 . Lisle, J T and Rose, J B (1995) Cryptosporidiwn Contamination of Water in the USA and UK: A Mini-Review J Water SRT - Aqua , 44 ,3, 103-117. Lohman, L (1987) 'Potable Wa stewater R euse Can W in Public Support' Proc W ater R euse Symposium , AWW A R esearch Fo undation, D enver, 1029-1043. M acCormick, A B and J ohnson , W T (1996) Tandem M embrane Trea tment of Secondary Sewage approaches the C urrent Price of Potable Water Watertech, AWWA, Sydney, 335- 342 New So uth Wal es R ecycl ed Water Coo rdinatio n Committee (1993) NSW Guidelines for Urban and Re sidential U se of R eclaimed Water Sydney. O livieri , AW, Ei senberg, D M , Cooper RC & Tchobanoglo us, G (1996) R ecycled Water: A Source of Potable Water: City of San Diego H ealth Effects Study Water and Science Technology , 33 , 10 - 11 , 285-296. Rogers, SE and Lauer, W C (1992) D enver' s D emonstration of Potable Water R euse: Water Q uali ty and H ealth Effects Testing Wat. Sci. Tech., 26 , 7-8, 1555-5 64 . R ose, J B , H aas, C N & Gerba, C P (1995) Microbio logical Monitoring, Pathogen R emoval Assessment and P ublic H ealth Risks Associated w ith R eclaim ed Water

R eport prepared for New South Wales R ecycled Water Coordination Committee, Sydney. Smyth , T (1992) Scheyville: A New Approach to the Disposal of Treated Effiuent Paper presented at AWWA (Vic) Wa stewa ter R eduction and R ecycling Conferen ce, Geelong Stander, G J (1979) Micro-Organic Compounds in the Water E nvironment and their lmapct on the Q uality of Potable Water Supplies Paper presented at the 26th Convention of the South African C hemical Institute, Port Elizabeth , South Africa State of Cali forn ia (1 78) Wa stewa ter R eclamation Criteria. An Excerpt from the C alifornia Code of R egulation s, Title 22, Div 4, Environmental H ealth D epartment of H ealth Services, Berkeley. van der M erwe, B and M enge, J (1996) Water Reclamation for Potable Reu se in W indhoek N amibia Watertech , AWWA, Sydney, 327- 334. van Lee uwen, J (1994) Water R eclamation: Selec tion of Unit Pro cesses Proc 4 th R ecycled Water Seminar, NSWRWCC/ AWWA, Newcastle, 65-73. Water R esea rch Commi ss ion (1990) Constru ction and Operation of the Cape Flats Water R eclamation Plan t and the Surveillance of the Recla imed Water Q uality R eport prepared by C ity Engineers D epartment, Cape Town.

Author Ian Law is Technical Director, CH2M Hill Australia Pty Ltd, PO Box 743 North Sydney 2060. '

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WATER

DRINKING WATER AND PUBLIC HEALTH Mike Muntisov T here are m ore than 10 million cases of gastroenteritis in Australia each year, according to Dr M argaret H ellard , an infectious diseases physician w ith the D epartment of E pidemiology and Preventive M edicine at Monas h University w ho spoke at A WW A's Melbourne branch m ee ting m D ecember last year. This represents an ave rage of 0 .7 gas tro incidents per person per year. An estimated 50% of cases result in a restriction of daily activity leading to the loss o f approximately five million wo rking days per year at an estimated co st to the communi ty of around $1 billion.

How Much of Gastro is Due to Drinking Water? T he short answer is that we do not know. O verseas studies suggest that between 15% and 30% of cases could be due to drinking water and Australian scientists at the C R C for W ater Quality and Treatment are conducting further research . Professor John M cN eil at Monash University is leading a p rogram of research into w ater quality and health risk assessm ent for the CRC fo r Water Quality and Treatment. T he major proj ect in the p rogram is the W ater Quality Study, w hich has the obj ective of determining whether the filtration of drinking water reduces the incidence of gastrointestinal disease in an area served b y a disinfected water supply drawn from pro tected catchments. It is hoped that the study will also allow evaluation oflinks between water quality guidelines and health outcom es and determine links between indicator organism s, water con sumed and health outcomes .

Household Survey The W ater Quality Study w ill involve a randomise d , do uble-blind experiment involving 600 households over 18 months. Half of the participating households w ill be fitted w ith a filter/UV system under the kitchen sink. The other hou seholds w ill be fitted w ith sham filters. The households w ill be questioned regularly on the water they have 14 WATER MAY/ JUNE 1997

con sumed and the inciden ce of gastroenteritis. Faecal and blood specim ens will be taken when appropriate . Ex tensive water quality sampling w ill be carried out in the supply area including for pathoge ns such as C ryptosporidium, G iardia and Ca mpylobacter. T he study is designed to detect a 15% o r grea ter difference in the incidence of gastroenteritis between the groups drinking filtered and unfiltered water. T his represents approximately one additional gastro attack per person every six years due to drinking water. The proj ect budget is $3 million and is fund ed by M elbourne W ater, the three w ater re tailers serving M elbourne, W SAA , D epartment of Human Services and the C R C .

Public Health Polley M elbourne W ater has developed a Public H ealth Policy that sets out its obj ec tive o f d elivering a low-co st , reliable supply of safe, high-quality drinking water that consistently m eets 1987 NHMRC health requirem ents. P eter Scott, G en eral M anage r of Science and T echnology at M elbourne W ater , o utlined the policy, w hich Melbourne W ate says is the first of its kind in Australia. M easures designed to fulfil the policy include res tricting public access to catchments, en sunng treatment pro cesses are reliable, undertaking research in water quality and public h ealth and providing relevant and timely information to customers and stakeholders. A m em orandum of understanding on public health m anagem ent will be finalised w ith the D epartment of Human Services and an annual environment and public health report w ill be published .

Water Quality Issues Brian Bayley, General M an ager W ater at M elbourne W ater, outlined the key water quality issues the w ater group is addressing. T hese include: • en suring that any increases in standards and treatment costs deliver

community benefits • to what extent should requirem ents of vulnerable segm ents of the community such as young and old people and groups with low immunity influence water quality standards ? • co mmunity attitude to ch emical d osing (chlo rine, fluorid e and aluminium salts) • establishing a strong relationship w ith the D epartment of Human Services and building on the recently formulated m emorandum of understanding maintaining high acceptance of M elbourne's drinking water (83% of M elburnians are happy w ith tap water) versus bottled water maintaining the protected status of M elbourne's water supply catchmentsthe unknown relevan ce in · M elbourne of Cryptosporidium as a cause of gastrointestinal illness. M elbourne W ater is carrying out or funding researc h to address these key issues . P roj ec ts include the water quality study being carried out by P rofessor M cN eil at M onas h University, health ri sk assessm ent m o delling and assessm ent of the risks of blu e- green algae follo w ing a rece nt bloo m at Y an Y ean R eservoir. Ca tchment sources of wa terb o rne micro-organism s are being investigated . As M elbo urne's catchments are protected , the obj ective is to identify animal sources.

APOLOGY Trials of Colilert System by PW Adco ck , C Saint in Water M arch/April , p. 22 In the section headed Analysis of Seeded Wa ters a significant phrase was deleted in the sub-editing, and thefo llowing correction emphasises the value of the Colilert-1 8 system: Colilert-1 8 should be examined after 18 h and if there are clearly yellow or fluorescing cells, the client should be advised , but also advised that a further examination is necessary at 22 h to give a final confirmed count. This strategy enables rem edial ac tion to be taken at an earlier stage .


WATER

TOP END AWASH IN 'BIG WET' Bill Bean A guaranteed four months of rain and eight months of no rain each year places Darwin in the dry tropics of Australia and gives it a perspective on water management that no other Australian city has . During the 'wet' there is sufficient rainfall to meet all water demands, while for the rest of the year groundwater is the predominant wa ter source for most of the Territory. . The tropical monsoon trough that swep t across the whole of the north of the continent recently produced unprecedented rainfall. It has bee n declared the 'wettest wet' on record, culminating in a six-metre tide during heavy rains on 1 M arch 1997, w hen the city's stormwater system was blocked off and local city flooding occurred. The Darwin area has several water supply sources. The main one, M anton Dam, has a rising main pump station that feeds water to the Darwin area and a groundwater bore fi eld ac ts as a supplementary feeder to the main line.

The Territory is unusual in that most of its water supply is from groundwater.

Water Mapping and Monitoring The Territory community is generally aware of water quality and supply problems and the Water Resources Division is running Waterwatch, an education program for schools, parents and local government, together with a number of other programs designed to map , monitor and manage water in the North.

Waterwatch Under Waterwatch communities are encouraged to monitor their own local water resources and to become involved with water management activities on the ground through regional coordinators. To date there are coordinators for Darwin, Gove and the Litchfield Shire, with another about to be appointed for Alice Springs. A Water Advisory Committee is

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producing a strategic plan to guide the development of the program so that it remains in line with the national program, yet reflects the Territory's unique geography and.demographics.

Monitoring River Health Another program is M onitoring River Health, a national program aimed at gaining insight into the status of Australian rivers. This initiative is developing a predictive model to determine river health based on the collection of water samples and aquatic macroinvertebrates including shrimps, insect larvae, worms, snails etc from undistrubed and disturbed river sites across Australia. Throughout the Top End, 120 sites in 13 river basins have been chosen for the study. Data will b e used to construct models for assessing the biological health of impacted river sites. Models will be used to monitor site remediation and river ~ealth recovery.

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WATER MAY/ JUNE 1997

15


WATER

SETTING PUBLIC HEALTH PRIORITIES IN DRINKING WATER QUALITY AND TREATMENT RM Douglas Abstract T he W ater Services Association of ¡Australia and the Cooperative R esearch Centre for W ater Quali ty and Treatment (CRC) convened a two-day meeting of 40 Australian experts in wa ter tec hnology, public h ealth , toxicology, wa ter manageme nt , epidemiology , microbiology and general water research in M elbourne in September 1996. Also present were tvvo expert advisers from Europe and the United States. T he purpo se of the meeting was to discuss desirable directions in the field of drinking water quality researc h and management, especially in relation to public health priorities. The full proceedings of the meeting, w hich include brief summaries of the technical presentations and the ro undtable discussions w hich took place , has been publi shed j ointly by the two sponsoring bodies and is available from the C RC in Adelaide . This article is a summary of the co nsensus reached by the group on a range of issues including research priori ti es , management initiatives and regulatory approaches.

Mlcroblological Risks The greatest public health ri sks from drinking wa ter have always been , and co ntinu e to be, from fa ecal-related microorganisms. These risks are likely to be considerably greater than those from chemical contaminan ts of water. W e need to invest more in understanding the nature of current microbiological risks and the precise order of their importance. Without better understanding, we could invest heavily in sophisticated treatment plants which might no t necessarily address the underlying problem s. Sa lm onella, Campylobacter, Cryptosporidium, Giardia and viru ses are likely to be the most important microbial pathogens, and we need to understand more abo ut the en1erge nt roles of cyclospora and toxoplasma. 16

WATER MAY/ JUNE 1997

In considering the recent filtered wa ter studies in Canada, we co ncluded that we need an Australian study to test the propo sitions that have been raised. These studies have sugges ted that despite modern water treatment there is a significant burden of gastrointestinal illness in Montreal that is apparently attri butabl e to drinking water . T he workshop endorsed plans for a rigorous randomi sed co ntrolled tri al 111 Melbourne w hi ch will com pare ga strointes tinal illness rates in two groups of people, one receiving ultrafiltered water at their ho usehold tap , w hile the other gro up receives normal mains wa ter that has been disinfected and comes from a well protected catchment. T he proposed M elbourne trial needs also to be supplemented by efforts to es timate the community multipliers that can be appli ed to es timates of endemic gastroi ntestinal illness in the participants in the trial. On the issue of innovations in detection methodology, we recognised the need to match pathogens obtained from water to pathogens obtained from clinical samples and the growing tec hnical capacity to 'fingerprint' organisms from vario us sources . This approach offers an additional cost-effective way of estimating the contribution of drinking water to human gastrointestinal disease. The current detec tion limits and cost of laboratory methods for so me m1 croorga111sms including ce rtain protozoa and viru ses make them barely useable for routine testing of water samples, but various Au stralian laboratories are working towards an improved capacity for standard kit testing and routine surve illance. The propo sed filter trial will provide an opportunity to marry 'state of the art' microbiology to both clinical and wa ter sample testing. We agreed o n the need for improved health and water data sets w hich can focus on specifi c public health qu estions. For example, there is a need for national collabora tive links, perhaps initi?ted through the CRC , to better relate the pathogen co ntent of water to

gastrointes tinal illness ra tes, and pathogens isolated from patients. On the issue of cyanobacteria, for many Australian water jurisdictions the managem ent of thi s problem 1s hampered by inadequate information and inadequate technology. W e do not know precisely how m uch toxin reaches the tap under varying conditions of treatment of blooms, nor do we have good documentation of the health effects of the toxins w hich we know to be present in many Australian source wa ters . The workshop has firmly recommended to the CRC that it maintains a strong commitment to this area of research.

Disinfection By-Products On the issue of' disinfec tion byprodu cts we noted the uncertainties surrounding their human toxicity. T he international data on carcinogenesis is as yet unconvincing, but it is strong eno ugh to signal the need to collect Australian data. It is clea rly good practice to keep these substances low and one way of doing so is to minimi se the organic carbon content of source waters. It is not clear that the limits currently specified in the guidelines are really justified on publi c health grounds and the workshop agreed that these are less important as a priority than m1croorga111sms but impo rtant nonetheless . Getting the level of trihalomethanes (THM s) under 200 micrograms per 100 mls is generally possible in Australia , but getting them lower w ill be difficult in some jurisdictions. It is not ye t clear if we are measuring the most appropriate disinfection by-products as markers of possible toxicity.

Alumlnlum Aluminium co ntinues to be an issue that ca uses public concern,. W e agreed that work commenced as a result of an earlier CRC workshop to identify the relative contributio n uf wa ter aluminium to body load is an appropriate direction for the research and that this should precede any maJor Australian epidemiologic studies.


WATER The Water Distribution System The Canadian filter studies have put the focus on the distribution system and the po ssibility that contamination by microorganisms may be amplified by prolonged transit of water in the reticulation system that can act as a biological reactor. R esearch into biofilms and factors which contribute to 's table water' deserves high Australian priori ty.

Water Supply Management

between publi c health authorities, researchers and water managers is highly desirable, and the groups need to work together to ensure that the information base on w hich information is made available to the public is comprehensive and up-to-date.

Regulations and Standards W e agreed on the need to avoid adversarial standard setting, while ensuring that accountability is open and comprehensive. W e also see a preoccupation with 'compliance' and ' numbers' as counterproductive to the central aim of producing good products . Microorganisms require very different approaches from chemicals w hen monitoring guidelines are developed, though there has been a tenden cy sometimes to treat them both similarly. The recently endorsed NH&MRC/ ARMCANZ guidelines provide excellent pointers to desirable best practice. These need to be kept up-to-date with international trends and national information as it com es to light. T here is a need to retain a prestigious independent age nt such as the

United States and proposed the consideration of a similar system here. Some m echanism whereby peer review of professional standards can take place under the auspices of the W ater Services Association of Au stralia, a H ealth D epartment or some other agency is highly desirable. An efficient auditing system will provide a guarantee of quality to the consumer as well as a legal defence in the event of problem s developing. The emphasis in all of our discussions has b ee n for a move to perfo rmance appraisal in delivering a good product to the consumer's tap . Furthermore, the integrated operation of best practice across the whole sys tem should be capable of linkage to public h ealth outcomes in those who receive and consume the water.

Our discussion of the place of risk assessm en t in wa ter management practice has highlighted the uncertainties inherent in risk assessment and the fact that there are very wide confidence intervals around most such estimates. This approach provides a mechanism for identifying danger areas and for highlighting areas w hich need particular Comment strengthening and attention . We The advent of the Cooperative debated the question of whether we R esearch Centre for Water Quality and should strive to unders tand risk or Treatment and the changing structures depend on good engineering practice to in the Australian water industry have remove the risk and agreed that both created new challenges and opportuniwere necessary. D espite its imprecision, ties for drinking water research and modelling of the water system provides regulation. By reviewing a useful pointer to potential international directions along system weaknesses. T he work 'An efficient auditing system will with the special needs and begun by the CRC in this area of Australian provide a guarantee of quality to the circumstances is both bold and innovative. communities, 'the clear view There was recognition that consumer as well as a legal defence in em erging from the discussion although the water agency's was that we n eed now in responsibility legally ends at the event of problems developing.' Au stralia to develop a quality the m e ter, the household sys tem approach that distribution sys tem 1s an overviews a water supply from the integral part of the system and may be a NH&MRC to continue to be responsi- catchment to the tap, and to set in place very important one. While 'aggressive' ble for updating and promulgating the surveillance and monitoring m echa quality guidelines. The water may be the cause of problems in water nism s that can improve our understandNH&MRC has played an important the domestic reticulation system , the ing of the relationship betwee n plumbing regulations in Au stralia need role in vetting new chemicals as they community health and water. were introduced into the industry. This to be standardised, and it is in the water There was clear recognition of a need industry's interests to ensure that this essential public health function will for the water industry to find better need to be maintained. aspect of the system is properly attended T he discussions made it clear that we ways of making consumers more aware to. cannot generali se the application of of water treatment tradeoffs between standards across Au stralia and that there acceptable risks on one hand and costs Community Education and on the other. The group also recognised are regional emphases as a result of Involvement that the corporatisation of Australian varying ground and surface waters, W e discussed at length the relation- differing climatic environments, differ- water authorities brings w ith it an ship between consumers and the water ing treatment system s and differing urgent need for a coherent approach to industry. There was firm consen sus that population needs. This means that the regulatory and quality issues, and that the CRC has played a valuable role in guidelines can form the basis for devel- we need to develop with natio nal providing a venue for debate and review oping and n ego t1atmg desirable authorities like NHMRC an approach of public health questions in which the standards for a regional or local water to standard setting that is based on community at large has a growing and jurisdiction , and that the emphasis public health need and views each water system in an integrated way . The legitimate concern. should be less on a slavish commitment that is developed mu st be approach W e recognised the need for to compliance with numbers, and more co nsumers around the nation to be on the cost-effective operation of the sensitive to Australian conditions and to ass ured that wa ter quality is being whole system that is directed towards the need to work with a wide range of source waters collected from the driest systematically reviewed on their behalf, public health safety. continent on earth . ' and that matters which affec t their 'Best prac tice' should be applied welfare are being rigorously monitored across the whole system from the catchand addressed. Spokespersons for the m ent to the tap, and the community Author Professor Bob Douglas is Director water industry need to be proactive in needs to be assured that this is happenrecogni sing the legitimacy of public mg. W e noted the operation of a water of the Nationa l Centre for Epidemiology and concern in areas in which the science is industry peer review sys tem in the Population H ealth at The Australian National University, Canberra. still imprecise. C lose collaboration WATER MAY/ JUNE 1997

17


WATER aluminium levels and species in a water supply system that distributes drinking water to part of the M elbourne metropolitan area. The Sugarloaf R eservoir is located north-east and 32 km from the centre of M elbo urne. The reservoir supplies the Winneke Water Treatmen Plant and is the one of the main sources of drinking and domestic wa ter for the North-East of M elbourne. Most of the aluminium in a natural water supply should be removed by trea tment using aluminium sulfa te (alum) as coagulant for suspended material even when the levels of aluminium are high (Van Benschoten and Edzwald , 1990; Yagi et al. , 1992; Nilsson , 1992) , but there is reas on to believe that di ssolved aluminium will remain and is readily available for absorption in the human gut (Broe and Coburn , 1990; Liss et al, 1990; WHO , 1993). The results of this resea rch work will be presented in three parts. Part 1 deals with aluminium levels and species and aluminium distributio n in the reservoir and Part 2 covers aluminium levels and species in every stage in the. Winneke W ater Treatment Plant. Both these parts are published in this article. Part 3, aluminium levels and species 111 samples taken fro m domestic tap wa ters supplied by the Winneke Treatment Plant, is still in prep aration and will be published in a future issue of Water. The r_esults of the research will give a clea r pi cture of the evolution of aluminium levels and species from the natural water resource through the water treatment plant to the domestic tap water supply .

ALUMINIUM IN A WATER SUPPLY BA Coller, J Lin . Abstract

colloidal suspended matter, including most micro-o rga nisms, by settling and filtration . It is clear that the use of aluminium sulphate in the process leads to a considerable decrease in the total aluminium concentration and does not add significantly to the level of dissolved forms of aluminium in the wa ter supplied to th e distribution system.

A study of aluminium levels and speciation in the water supplied from the Sugarloaf R eservoir, M elbourne, is reported as part of a wider investigation. The results show the distribution of total aluminium , filtered aluminium (through 0.45 µm and 0.003 µm filters), particulate aluminium (larger than 0.45 µm) , colloidal aluminium (smaller than 0.45 µm , but larger than 0.003 µm) , total monomeric aluminium and individual monomeric inorganic aluminium. In the reservoir, higher levels of aluminium were often found in the upper parts (cycling zone) because water is pumped into the reservoir daily from the Yarra River and forced to m ove forward . Colloidal particles remain su spended and cycle with the wa ter flow in the upper parts. The total aluminium levels at the sample point were found to correlate with the turbidity; the higher the turbidi ty the hi gher the aluminium levels. The tu rbidi ty was also related to recent rainfall; the more rainfall the higher the turbidity. At Winneke Treatment Plant aluminium sulphate in solution is added to promote coagulation and allow removal of remaining particulate and

Turbidity / NTU

1

1 .5

2

2 .5

3

3 .5

Introduction R ecent interes t in aluminium in water arises from the suspicio n that it affects human health and environment. It has been discovered that no t all aluminium species are equally toxic and it also has been found that monomeric inorganic aluminium in natural waters is toxic to plants (Cronan et al. 1989, Shuman et al. 199 1), fi sh (N eville and C ampbell 1988, M cCahon et al. 1989), and eve n human beings (Bro e and Coburn 1990, Liss et al. 1990, Landsberg et al. 1992). For reasons of human health and environmental safety, it is very important to understand aluminium levels and their particular speciation in drinking water. Until now, there has been little study of aluminium levels and species in M elbourne drinking wa ter. T he aim of the work is to investigate

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Figure 1 Turbidity profiles in the water column of the Sugarloaf Reservoir 18

WATER MAY/JUNE 1997

1 .5

2

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Turbidity / NTU

Figure 2 The relationship between total aluminium and turbidity in the water from the Sugarloaf Reservoir


WATER

Part 1: The Sugarloaf Reservoir, Melbourne This paper reports a study of aluminium levels and speciation in the raw water of the Sugarloaf Reservoir in the winter, spring and summer of 1993 to 1994. As part of the investigation, a numb er of other components were analysed for future reference.

Sugarloaf Reservoir The reservoir is an area of about 450 hectares, with a local ca tchment area of 930 hec tares . T he m aximum water depth is about 80 m and the water storage capacity is approximately 95,000 megalitres (ML). · When in service, water is pumped daily from the Yarra River and the M aroondah Aquedu ct into the reservoir at up to 1,000 ML per day. The inlet structure supplies wa ter at abo ut 20 m depth, well below the full supply level of the reservoir. T he offtake structure draws water at about 50 m depth , and delivers it by gravity to the Winneke Water Trea tment Plant.

Sampling and Analysis O ur four inves tiga tions passed through three seasons: the end of winter (6 September 1993), spring (4 O ctober 1993 and 8 Novemb er 1993) and summer (24 J anuary 1994). The sampling point was located at the middle of the reservoir about 3 km from the inlet and 1 km from the offtake points. W ater samples were taken from a small boat with a 2 L Van Dorn (plastic) wa ter sa mpler at various depths. Samples for determination of aluminium , iron and manganese were kept in 1 L polye thylene bottles; samples for determination of fluoride, chloride, silica, sulphate, phosphate, nitrate and nitrite were kept in 250 mL polyethylene bottles; and samples for the total organic carbon (TOC) determinations were kept in 50 mL glass bottles. polye thylene bottles for All alumini um de terminations were clean ed u sing the following steps. Firstly, the bottles were soaked in 10% HNO 3 solution for at least one day, then in EDTA solution (6 g/L) for fo ur hours, and lastly in Milli-Q water for one day. The bottles for other analyses were soaked with 10% HNO 3 solution, and later clea ned with Milli-Q water. W ater samples were refrigerated until analysis at 4°C for aluminium on the same day and for iron and manganese within three days. pH , temperature, dissolved oxygen, dissolved oxygen saturation , elec tric conductivity and redox potential were

determined by an in situ water quality data system at the reservoir. Fluoride, nitrate, nitrite, phosphate, sulphate and alkalini ty were analysed by ion chromatography (IC), chloride and silica by flow injection analysis (FIA) and total organic carbon by TOC analyser. Some fluoride concentrations were analysed by a fluoride ion-selective electrode to get more accuracy for the calculation of individual monomeric inorganic aluminium species. Total aluminium (Altoral) was determined by graphite furnace AAS after with 5% HNO 3 diges tion (APHA 1989) . Acidified aluminium (Al 1% H N0 3) was obtained by acidification to 1% HNO 3 with no further treatment, and samples for determination of filtered aluminium (Al<o. 4sµm' Al<o 003 µm) were acidified with 1 o/o HNO 3 (Driscoll 1984) . Filtrations were performed by gravity flow filtration through Millipore filters (0.45 mm) and by tangential flow filtration through Minitan filter plates using a Minitan Ultrafiltration System from Millipore, USA (0.003 mm). Total monomeric aluminium (Alm 000 ) was extracted after reaction with 8-hydroxyquinoline at pH 8.3 (Barnes 197 5, LaZerte 1984, Loescher 1984) and a ca tion exchange column was used to separate monomeric inorganic aluminium (Alinorg) from monomeric organic aluminium (Al 0 r ) (Driscoll 1984). In the present wor~, particulate aluminium (Alparticle) and colloidal aluminium (Alcolloid) were defined by difference as follows: Alf"rti cle = Al tota l - Al <0.4S µm a nd A co lloid = Al <0.45 µm - Al <0.003 µm

month, the water level of the reservoir is very stable. The water quality in the reservoir was very good , as indicated by pH (6.67.4), low values of suspended material (0.71-2.51 mg/L) , turbidity (1.7-3.8 NTV) , colour (19-25 PCV) , electric conductivity (65-68 µ S/cm) and other parameters. The turbidity in f-he water of the reservoir is affected by the turbidity of the water inputs from the Yarra River and the Maroondah Aqueduct, w hich are affected by recent rainfall and the stream flow: the more recent rainfall there has been , the higher the stream flow and turbidity. Figure 1 shows the turbidity profiles in the water column of the Sugarloaf reservoir, showing that the turbidity in the period of spring rainfall at first rose with the depth from the surface waters through the upper waters , and then dropped progressively toward a steady value in the deeper waters. This corresponds to fresh water with mud (clay) being inj ected into the upper waters at abo ut 20 m below the surface of the reservoir during the period from October to November. An approximate , proportional the total relationship between aluminium and turbidity at the sample point is demonstrated by F~gure 2. T ables 1 to 4 and Figure 3 show the profiles of levels of different aluminium species in the water column of the reservoir. Altotal levels ranged from 174 µ g/L to 193 µ g/L in September, 190 µ g/L to 420 µg/L in O ctober, 193 µ g/L to 281 µg/L in November and 112 µ g/L to 195 µg/L in January. Most of the total aluminium levels were below 200 µ g/1, except in O ctober w hen there had been Individu al monomeric inorganic more rain just before sampling. The aluminium species levels were Altotal levels were close to uniform from computed from total m o nomeric the surface to the bottom in September. inorganic aluminium together with However, in the other three months the established values of equilibrium Altotal levels increased at first from the co nstants by using the MINTEQ surface with the depth, then dropped computer program (U.S. EPA 1988) toward the middle, and were stable and using measured values of tempera- from the middle to the bottom. In ture , pH , and concentrations of fluoride September, Al %HN0 was 62-69% of 1 3 and sulphate. the total aluminium (AltotaJ), in O ctober The colloidal distribution in a water 77-95%, in November 72-94% and in sample from the Sugarloaf R eservoir J anuary 71-91 % . T he order of was determined by sedimentation fieldaluminium fractions in most cases was flow fractionation (SdFFF) using coagulation (Be ckett et al. 1988). The Alparti cle > Al <0.45 µm > .i; 1coll oid > co ncentration factor was about 100: 1 in Al <o.oo3 µm· The levels of Altom!' Al 1% H No 3, our experiment. Alparticle' Al<0.45µm and Alcolloid increased Results and Discussion from September to O ctober, then Because the water is pumped into the decreased from O ctober to November reservoir daily and less than 10% of and decreased again from November to storage volume is withdrawn per J anuary . Howeve r, the levels of WATER MAY/ JUNE 1997

19


WATER Al levels/(ug/L) 6.9 .93 0

Al levels/(ug/L)

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Figure 3 Aluminium profiles in the water column of the Sugarloaf Reservoir

dissolved aluminium (Al<o.oo3µm) appeared similar in all months . The levels of total monomeric aluminium (Almono) were very close to the levels of aluminium passed through 0 .003 µm filters (Al<0 _003 µm). The measured amounts of Alinorg and Alorg were almost equal, and according to equilibrium calculations the main forms of monomeric inorganic aluminium were aluminium combined with OH to form Al(OH) 3 , Al(OH) 4 and Al(OH) 2 +. The largest fractions in this speciation would have been Al(OH) 3 , then Al(OH\-, while the fractions of Al(OH) 2+ would have been very small. The percentages of various aluminium species in the water of the reservoir from the four investigations are shown in Table 5. The percentages did not appear to vary significantly from month to month. It is clear from the 20

WATER MAY/JUNE 1997

iron occurred as particulate iron (larger than 0.45 µm , 44% ) and colloidal iron (smaller than 0.45 µm , but larger than 0.003 µm , 53% ). On average, the levels that passed through 0.003 µ m were a small fraction (7%) of the total iron. The colloid particle size distribution revealed by sedimentation field flow fractionation (SdFFF) showed a broad peak in the range from 0.03 to 0.3 µm with a maximum at abo ut 0.08 µ m . The cumulative masses up to 0.1 µ m were about 20% and up t:6 0.45 µ m abo ut 85%. This means that most of the su spended matter was in particles smaller than 0.45 µ m , and a significant fraction was smaller than 0.1 µm . Silica and iron concentrations in the upper parts were almost always higher than in the deeper parts of the wa ter column as indicated by the iron and silica profiles. This is attributed to there being more colloidal particles in the upper water due to circulation caused by the pumped inlet. W e found two different types of water in the reservoir, one in the cycling zone in the upper parts of the reservoir, and the other in the stable zone in the deeper parts of the reservoir.

---Al <0.45 um ---Al1 % HN03 --Al total

averages that most (53% + 43% ) of the aluminium occurred as Al,rarticle (larger than 0.45 µ m) and Alcolloid ,smaller than 0.45 µm , but larger than 0 .003 µm ) and that most (79% ) of the aluminium could be solubilised by 1% HNO3 (V/V). The percentage of Almono is a very sm all fraction (6%), becaus e aluminium is a strongly hydrolysing metal and is relatively insoluble in the neutral pH range of 6.0 - 8.0 (Stumm and Morgan 1981). The pH values in our samples ranged from 6.3 to 7.4, so only very small fractions, abo ut 6% and 3%, were prese nt as monomeric aluminium and monomeric inorganic aluminium, respectively. The observation that most of the aluminium in the water of the reservoir occurred as Alparticle and Alcolloid is parallelled by the percentages of iron species in th<,: water of the reservoir (Table 6) . On average, most (44% + 53%) of the

T he following conclusions concerning aluminium in the raw wa ter of the Sugarloaf Reservoir can be drawn. T he levels of total aluminium in the water of the reservoir were more or less directly proportional to the turbidity. The turbidity of these input waters was affected by recent rainfall and the consequent stream flow. The aluminium levels in the upper parts of the water at the sampling point were higher than in the deeper parts of the reservoir. Aluminium distribution did not depend so much on the depth as on the movem ent of waters in the reservoir; water is pumped into the reservoir and drawn out daily and this drives the water cycling in the upper parts of the reservoir, while the deeper water remains stable. Larger particles appear to sediment out steadily w hi le the colloidal particles cycle with the water flow in the upper parts. Most of the aluminium species in the water of the reservoir were present as particulate (larger than 0.45 µm , 54% ) and colloidal aluminium (smaller than 0.45 µ m , but larger than 0.003 µm, 43% ). Most (80%) of the aluminium would be soluble in 1% HNO3 (v/v). Only very small fractions were present as monomeric aluminium and monomeric inorganic aluminium, about 6% and 3%, respectively. M ost of the aluminium comes into the reservoir as particulate and colloidal aluminium.


WATER

Part 2: The Winneke Treatment Plant, Melbourne .Part 2 of this paper describes the evolution of aluminium species in the Winneke Treatment Plant (WTP) associated with the Sugarloaf Reservoir. Winneke WTP is the largest water trea tment facility in the M elbourne area. The WTP has a design capacity of 450 ML per day, but it is normally only used for peak summer demand. Raw water is delivered from the Sugarloaf R eservoir via an offtake structure 50 m below the fu ll level. It is coagulated using alum , lime and polyelectyrolyte, then clarified, with a retention time of approximately three hours . Conventional sand filters deliver filtered water for chlorination and pH adjustment, then to a 200 ML clear water reservoir. T he water supplied to reticulation is fluoridated at a facility som e 10 km downs tream.

Sampling and Analysis Sampling of waters. The sampling

of waters in the plant occurred at all six stages of the treatment system. Samples were treated as summarised in Part 1. pH , temperature and turbidity were determined at the Winneke Treatment Plant immediately after the sampling. Electric conductivity, redox potential and colour values were measured, and water filtration carried out within the day of the sampling. Gravity flow filtration (GFF, pore size 0.45 µ m) was used to separate particulate su spended matter and tangential flow filtration (TFF , pore size 0.003 mm) was used to retain colloidal suspended matter and permit more reali stic determination of dissolved aluminium. Individual monomeri c inorganic aluminium species were computed by MINTEQ co mputer program (U.S. EPA 1988) using measured values of temperature, pH , fluoride, sulfate and total monomeric inorganic aluminium levels. Fluoride, chloride, nitrate, nitrite, phosphate, sulfate, silica, alkalinity and total organic carbon were analysed within one week of sampling.

Results and Discussion Alumlnlum and Other Parameters in the Raw Water. R esults of our investi-

gations for the Winneke Treatment Plant on 21 September 1993 and 24 January 1994 are summarised in Figures 1, 2 and 3. Figure 1 shows that the total concentration of aluminium in the raw water entering the treatment plant was approximately 200 µg/L, the criterion level set by NHMRC/AWRC (1987)

and recommended by WHO (1993) . Dosing with a solution of aluminium sulphate to promote coagulation of suspended matter raised this concentration more than fi vefold , but the co mbined effect of settling and filtration reduced the total aluminium concentration in the sample to about 30 µ g/L, less than one fifth of the original concentration in the raw water and well below the figure of 100 µ g/L that ha s been propo sed as a desirable criterion to improve the margin of safety for drinking water quality. Water samples were filtered in the laboratory by gravity flow through pore size 0.45 µm , small enough to exclude almost all organisms except viruses. This redu ced the total aluminium concentration in the sample to less than 100 µ g/L. After do sing, the filtered water contained le ss aluminium , indi ca ting that the addition of aluminium sulphate had reduced the amounts of colloidal suspended matter with which previou sly filterabl e aluminium was associated. Samples taken after se ttling of coagulated material we re fractionally lower in filterable aluminium, but it is no surprise to see that filtered water and water treated with chlorine and lime were little different from the settled water in this respect. T angential flow filtration of samples through pore size 0.003 µm was used to filter out all except the simple molecular and ionic chemi cal species that are believed to make aluminium readily available for absorption in the digestive system. The latter are expected have diameters of the order of0.001 µm and thus to pass through the filter. In raw water samples, after TFF , aluminium remained at about 8 µg/L, only about 10% of the concentration that passed the 0.45 µm filter. Water dosed by addition of di ssolved aluminium sulphate had only about twice this level of ' dissolved' aluminium even though the higher total level of aluminium had increased by a factor of fi ve. During dosing, the primary processes of coagulation are caused by adsorption of aluminium ions (Al3J from solution onto particulate and colloidal suspended structures, n eutrali zing their surface charges and allowing them to stick together. The levels of ' dissolve d' aluminium in settled and filtered waters are each about one third lower than at the preceding stage, indicating that aluminium ions continue to be adsorbed onto the solid particles that are being removed by settling and filtration in the plant. The final water (or transfer water)

had 'dissolved' aluminium (<0 .003 µm ) of approx 10 µ g/L, essentially the same as in the raw water, but without the accompaniment of particulate and colloidal suspended matter that could possibly act as a reservoir for release of more aluminium into solution in the digestive system. Figure 2 shows the concentrations of iron obtained by .anal sis of the whole water samples after total digestion and digestion with dilute nitric acid and by analysis of the samples after gravity flow 10

'

<>

Al(lotal)/(ug/\.) Al(<0.45 um)/(ug/L)

9

Al{<0.003 um)/(ugll)

I

100

'

1000

i

'

<>

<

<>

<>

9

0

~

9

9

9

<>

9

10

9

1 L----L-.....l..-..J....._.J..____,Jc___,__....J dosed

rtM

settled ffler8d treated transfer Stage of Treatment

Figure 1 Aluminium concentrations at the various stages in the Winneke Treatment Plant averaged values for the two dates of sampling ,.

1000

• ;

100

J

• • •

Fe(total)/(ug/L) Fe(t%HN03~(ug/L) Fe(<0.45 um)/(ug/1.) Fe(<0.003 um)l(ugl\.)

• •

10

raw

dosed

••

;

1

settled filtered treated transfer

Stage of Treatment

Figure 2 Concentrations of iron and its fractions at the various stages in the Winneke Treatment Plant (averages for samples taken (1) on 21 September 1993 and (2) on 24 January 1994). Values less than the detection limit of 1 µg/L are arbitrarily set at 0.5 µg/L. 10

8

. .. . . .. .. ~ 0

0

0

4

2

e V

0

0

0

0

...

6

-

V

.. V

¥

i

0

pH

Alkdnilyl{mgCeCOM.)

o

Sulph1t.,(M'1¢l

e

Plrtlcl.lllhSM/{mg,\.)

V

TotalC>rg C/(mo,,\.)

j,

dostd8ellladhred!INl.cl!rw1*

Figure 3 Other water quality parameters for the Winneke Treatment Plant (pH, alka linity, sulphate, particulate SM, TOC - averages for the two sampling dates) WATER MAY/JUNE 1997

21


WATER Table 1 Resu lts of Al, Fe and Mn (µ/L) for the S ugarl oaf 25 45 Depth (m) 0 5 35 193 190 183 174 180 Al tota l 127 124 120 123 109 Al 1% HN03 112 102 95 112 116 Al particle 91 71 62 64 95 Al <0.45µm 76 ND ND 54 ND Al co ll oid ND ND 15 ND 8 Al <o.oo3µm 14 9 9 8 7 Al mono 4 4 3 3 3 Al org 10 6 5 5 4 Al inorg Al Al Al

Offtake

Inlet*

177 106 111 66 59 7

5203 4608 4914 289 257 32

7 3 4

7 3 4

31 15 16

ND ND ND

ND ND ND

4 1 <1

ND ND ND

3 1 <1

3 1 <1

12 13 1

211 208 112 99

182 169 94 88

215 200 105 110

207 174 98 109

202 190 105 97

204 196 100 104

204 ND 107 97

1824 ND 142 1682

4

4

4

4

5

5

5

36

Al (OH) 4Al (OH)2 +

Mn

70 187 122 114 73 66 7

7 2 1

Al (OH) 3

Fe total Fe 1% HN03 Fe <o.4sµm Fe parti cle

Reservoir on 6.9.1993

total

*Yarra River

ND: Not detected

Table 2 Results of Al, Fe and Mn (µg/L) for the Sugarloaf Reservoir on

4 .10.1993 Depth (m)

0

5

25

35

45

70

Al tota l Al 1% HN03 Al <0.45µm Al particle Al colloid Al <0.003µ m

331 301 150 181 138 12

420 322 164 256 ND ND

321 250 140 181 ND ND

206 167 105 101 98 7

190 180 101 89 ND ND

198 175 97 101 90 7

12 6 6

12 6 6

8 4 4

7 3 4

6 3 3

6 3 3

226 195 122 104 105 17 4

237 204 126 111 ND ND 4

251 197 117 134 ND ND 5

206 177 121 85 109 12 5

178 162 120 58 ND ND 5

174 168 116 58 102 14 6

3 Mn 1%HN03 1 Mn <0.45µm 3 Mn particle Mn <O.oo3 µm ND: Not detected

4 2 2

4 2 3

4 2 3

4 2 3

5 3 3

Al Al Al

mono org inorg

Fe total Fe 1% HN03 Fe <0.45µm Fe particle Fe colloid Fe <o.oo3µ m Mn tota l

Table 3 Results of Al, Fe and Mn (µg/L) for the Sugarloaf Reservoir on

8.11.1993 Depth (m)

0

5

10

25

35

45

Al tota l Al 1% HN03 Al <0.45µm Al pa rticle Al colloid Al <o.oo3µm

216 156 123 93 103 20

281 231 137 144 ND ND

278 211 123 155 ND ND

226 190 95 131 ND ND

202 167 93 109 82 11

196 157 87 109 ND ND

193 154 73 120 63 10

213 170 94 119 84 10

2330 1957 234 2096 202 32

20 9 11

14 7 7

14 7 7

11 5 6

10 5 5

10 4 6

10 4 6

10 5 5

32 17 15

184 124 60

205 130 75

198 128 70

178 102 76

147 92 55

147 87 60

131 77 54

157 91 66

2152 130 2022

5 Mn tota l 2 Mn <0.45µm 3 Mn particle ND: Not detected

5 2 3

6 2 4

5 2 3

5 2 3

5 2 3

8 4 4

5 2 3

31 9 22

Al mono Al org Al inorg Fe total Fe <0.45µm Fe particle

22

WATER MAY/ JUNE 1997

70 Offtake

Inlet

filtration and after ultrafiltration using tangential flow. The total concentrations of iron in the raw waters were ap proximately 206 ± 46 µg/L of which 137 ±5 µg/L was made available by digestion with dilute acid. As expected, total iron concentrations were altered little by dosing with aluminium sulphate, although increases of 8 and 19 µ g/L may have been due to the prese n ce of iron in the alum. However, settling of coagulated matter reduced total iron in the waters to 54 ±8 µ g/L and filtering through pore size 0.45 µ m further redu ced the iron concentration in samples taken on day (2) to 27 µg/L, a level that was also found in the water treated with chlorine and lime and in the treated water held ready for transfer. Samples of filtered, treated and transfer waters taken on day (1) had lower co ncentrations of iron, and considerable differences between these concentrations, as if the three waters sampled in the different parts of the plant at this time had somewhat different histories. R aw water filtered through 0.45 µm pore size retained about half its iron content (102 ±19 µ g/L), w hile dosed water retained less than 5% (5 .5 ±3.5 µ g/L) after filtration and furth er decreases were evident in settled waters (3 µ g/L) , filtered waters ( 1 µ g/L) and transfer waters (1 .5 ±0.5 µg/L) . It is clear that dosing led to iron being taken up by the coagulation of particulate and colloidal suspended matter. As expected, dosing with aluminium sulphate led to a more than threefold increase in sulphate ion concentration, w hich remained throughout the stages of treatment in the plant. Particulate suspended m atter showed a similar increase as a result of dosing, but this was more than reversed by the settling of coagulated particles and was further reduced by filtration. The pH value fell from near seven to near six on dosing and this was accompanied by approximate halving of the titratable alkalinity, the latter being restored when the pH was adju sted by the addition of lime after trea tment. Total organic carbon content of dosed water was similar to that of raw water, but TOC was approximately halved when coagulated solids settled out. Filtering through beds of sand had little further effect on TOC.

Conclusion Most of the aluminium comes into the reservoir as particulate ~nd colloidal aluminium. Only a small fraction (approx 9%) is present in dissolved form . Sedimentation of much particulate matter occurs while the raw water is held in the reservoir, but makes no significant difference to the dissolved aluminium fraction.


WATER At W in neke Treatment Plant, alu minium sulp hate in solution is added to promote coagulation and allow removal of remaining particulate and colloidal suspended matter, including most micro- organisms, by settling and fi ltration. It is clear that the use of aluminium sulphate in the process leads to a conside rable decrease in the total aluminium concentration and does not add significantly to the level of dissolved forms of alu mini um in the wa ter suppli ed to the distribu tion sys tem , which remained at ca lOµ g/L.

Acknowledgements Thanks are due to Melbourne Water for permission to carry out this study, to Noel M iles at W inneke Treatme nt Plant for assistance in planning and sampling and to Alex Harrison and Robyn Reid at Melbourne Water Laboratory for assistance with some of the analyses.

Table 4 Results of Al, Fe and Mn (µg/L) for th e Sugarloaf Reservoir on

24 .1.1994 Depth (m)

0

5

10

25

35

45

Al total Al 1% HN03 Al <0.45µm Al particle Al colloidal Al <0.003µm

112 102 68 44 53 15

150 136 81 69

195 143 87 108

132 112 71 61

120 105 74 46

ND ND

ND ND

ND ND

136 96 73 63 63 10

12 5 7

10 5 5

10 5 5

9 4 5

5 1 1

ND ND ND

ND ND ND

160 142 94 66

183 133 125 58

9 7 2 7

13 10 7 6

Al Al Al

mono

Al Al Al

Al(OH)3

org inorg

Al(OH)4Al(OH )2+

Fe total Fe 1%HN03 Fe <0.45µm Fe particle Mn Mn Mn Mn

total 1%HN03 <0.45µm particle

70 0fftake

Inlet

ND ND

121 108 69 52 60 9

162 146 64 98 54 10

1745 1461 105 16 40 76 29

9 4 5

8 4 4

7 4 3

10 5 5

28 17 13

ND ND ND

4 1 <1

ND ND ND

2 1 <1

4 1 <1

10 2 1

230 150 100 130

221 138 110 111

220 150 120 100

178 14 0 1 08 70

212 145 96 116

253 144 121 132

19 11 1250 2 17 1694

15 11 10 5

12 10 9 3

14 11 10 4

16 12 13 3

102 92 82 20

8 5 2 6

48 48 9 39

"'

ND: Not detected

References ANZE CC/ NHMRC (1994). Draft standard recommended for Al. Copy supplied by Dr Graeme Batley, CSIRO Ce ntre for Advanced Analytical Chemistry, Lu cas H eights R esearch Laboratories, NSW 2234. APHA, American Public H ealth Association. Methods for the 1989 . Standard Examination of Water and W aste W ater. 17th Ed. American Public Health Association. Washington, D.C. Barn es, R .B. 1975 . The determination of specific form s of aluminiu m in water. Chem. Ceo/. 15: 177. Beckett, R ; Nicholson, G; H art , B.T; Hansen, M. and Giddings, J.C. 1988. Separation and size characterization of colloidal particles in river water by sedimentation fi eld-flow fractionation. Water R es. 22 : 1535 . Broe, M.E. and Coburn, J.W. 1990. Aluminum and renal failure. Kluwer academic publishers. Dordrecht/Boston/London. ronan, C.S. et al. 1989. Aluminum toxicity in forests exposed to acidic deposition: the albios results. Water, Air and Soil Pollution. 48: 181. Ori coll , C.T. 1984. A procedu re for the fractionation of aqueous aluminum in dilute acidic waters. [nt. J. Environ. Anal. Chem. 16: 267. Landsberg, J.P.; M cDonald, B. and Watt, F. 1992 . Absence of aluminium in neuritic plaque cores in Alzheimer's disease . Na ture. 360: 65. LaZerte , B .D. 1984. Forms of aqueous alumin um in acid ifi ed ca tchments of Central Ontario: a methodological analysis. Can. ]. Fish. Sci. 41 : 766. Liss, L.; Long, J. and Thornton, D. 1990. Chapter 18 : Aluminium neurotoxicity, disease, and alcoholi c Alzheimer's In : Environmental encephalopathy. C hemistry and Toxicology of Aluminium. Lewis, T.E . Ed. Lewis Publishers, INC . USA. Loescher, B. 1984. Aluminium speciation in natural waters. (Atomic absorption) Varian instruments at work. AA-40. McCahon , C.P .; Bron, A.F.; Poulton , M.J. and Pascoe, P. 1989. Effects of acid, aluminum and lime additions of fi sh and invertebrates in a chronically acidic W elsh. Water, A ir, and Soil Poll11tio11 . 45: 345. Melbourne Water (1992). Winneke Treatment Plant. M elbourne Water.

Table 5 Aluminium species as percentages of total alum inium for fo ur investigat ions Spec ies Al 1% HN03 Al particle Al <0.45µm Al co ll oid Al <0.003µm Al mono Al inorg

6 .9 .1993 65 59 41 35

(6 1 -67) (50-64) (36-50) (31-40) 5 (4-7) 5 (4-7) 3 (2-5)

4.10. 1993 85 53 47 45

(77-95) (47-61) (39-53) (42-48) 4 (3-4) 3 (2-4) 2 (1 -2)

8. 11.1993 80 54 46 41

(72-8 4) (43-62) (42-57) (33-48) 6 (5-9) 6 (5 - 9) 3 (3-5)

24. 1.1994 84 45 55 49

(71-9 1 ) (38-55) (45-62) (47-51} 8 (6-11) 7 (5-11) 4 (3-6)

Ave rage

79 53 47 43

(6 1 -95) (38-64) (36-62) (31-51) 6 (3 - 11) 6 (2- 11) 3 (1 -6)

Table 6 Iron species as perce ntages of total iron Species Fe Fe Fe Fe

particle <0.45µm

6 .9.1993

4 .10.1993

8 .11.1993

24.1.1994

Average

50 (47 - 53) 50 (4 7 - 53)

42 (33-53) 58 (47-67) 53 (46-59) 7 (6 - 8)

38 (33-43) 62 (57-67)

46 (39-57) 54 (43-68)

ND ND

ND ND

44 (33-57) 56 (4 2-68) 53 (46-59) 7 (6-8)

co lloid <0.003µm

ND ND

ND : Not detected

N eville, C.M . and Campbell , P.G.C . 1988. Possible mechanisms of aluminum toxicity in a dilute, acidic environment to fingerling and older life stages of salmonids. Water, A ir and Soil Pollution. 42: 31 1. NHMRCJAWRC (1987). Guidelines for Drinking Water Quality in Australia. National H ealth and Medical R esea rch Council and Australian Water R esources Council. Au stralian Government Publishing Service, Canberra . Nilsson, R. (1992). R esidual aluminium concentration in drinking water after treatment with aluminium or iron salt or apatitehealth aspects. Water Supply 10(4): 55 . Shuman , L.M. ; Wilson, D.O. and Ramseur, E.L. 1991. T estin g aluminum-chelate equilibria models using sorghum root growth as a bioassay fo r aluminum. Water, A ir, and Soil Poll11tion. 57- 58: 149. Stumm, W . and Morga n, J.J. 1981. Aquatic C hemi stry. 2nd Ed. Wiley- lnterscience . New York. U.S . EPA. Center for Exposure Assessment Modelling, U.S. Environmental Protection of Research and Agency, Office D eve lopment , Environmental Research Laborato ry. 1988. M etal Speciation

Eq uilibrium Mod el fo r Surface and Groundwater (M INTEQ ). Ath ens , Georgia, U.S.A. Van Benschoten, J .E. and Edzwald, J.K. (1990). M easuring aluminium during water treatm ent : methodology and application. AWWA. May: 71. Yagi, M. ; Mizukawa , K. ; Kajino, M. ; Tatumi , S. ; Akiyama , M. and Ando, M. (1992). Behaviour of aluminium in water purification process at purifi cation plants in the RiverYodo system . Water Supply 10 (4): 65 . WHO (1993) . Guidelines for drinking water quali ty, Vol. 1, R ecommendations. World H ealth

Authors Dr Bruce Coller is Senior Lecturer specialising in trace metals andlysis in the Department of Chemistry, Mon.a sh Univers ity, C layton Victoria 3168. Dr Jlanplng Lin ga ined his PhD at Mon.ash, then completed a postdoctoral year at the Univers ity of Wyoming. H e specialises in trace analysis of environmental waters. WATER MAY/ JUNE 1997

23


FEDERAL

CONVENTION

WATER IN THE BALANCE AWWA 17TH FEDERAL CONVENTION EA (Bob) Swinton M elbourne proved an excellent ho st anoth er su ccessful AWW A for Convention and Oz water & Ozwaste Trade Exhibition in early M arch. The World Congress Centre provided · excellent ve nues for the techni cal sessions, though it has been reported that a couple of delegates are still wand ering aro und the lower corridors looking for the way out of the mazelike Corryong Rooms. Altogether there were 850 delegates for th e three- day co nve ntion and technical visits, and 300 workshop delegates. The organising committee led by Bill Robertson of Melbourne Water did a wonderful job-the whole event was flawless, low key and typically 'M elbo urne.' All memb ers of the organising Committee and the AWWA federal office staff led by M argaret Bates are to be congratulated . The Oz water & Ozwaste exhibition was a huge success, with 150 booths and at least 50 companies di sappointed at not being able to ge t a booth. Margaret plans to ' turn cartwheels' at the next conve ntion to be held in Brisbane by increasing the exhibition to 200 booths. This year AWWA was pleased to welcome a large number of international delegates and a contingent from the U.K., who ran nine booths as part of newIMAGES, a year-lo ng program of British events being held throughout Australia.

Opening T he opening ceremony began promptly at 9 am on Monday 17 March with a video to mark the convention theme, Water in the Balance. After the formal welcome by o ur President, M ark Pascoe, and a response on behalf of the international delega tes by Billy G . T urner, President of the W ater Environment Federation, we were trea ted to an off-the-cuff address by the Governor ofVictoria , Richard E. M cGarvie, w ho challenged the scientists and engineers in the audience from a lawyer's perspective to ensure the long-term sustainability of our water resources, and to take ac tion. 24

WATER MAY/ JUNE 1997

Barry Norman , AWWA Victorian Branch President , and Bill Robertson , Co nvention C hairma n , took the lectern. The opening ceremony concluded with a modern ballet perfo rmance, Ca lm After the Storm, against a fastmoving, tumultuous video backdrop illustrating the power of water. The keyno te spea kers were well chose n and challenging, and represented eac h of the streams of the co nvention. Summaries of their presentations are printed below. The speakers were backed up by a range of notables from within and outside the international water industry, w ho presented papers both in the plenary sessions and in the streams.

Technical Sessions The technical sessions had a different emphasis from tho se of previous co nve ntions, a shift w hi ch was foresha dowed in 1995 in the plenary sessions at the Sydney Convention. Two streams out of the four, Innovation in R egulation and T he Water Business, were devo ted to bu siness. The Organising Committee considered this appropriate considering the radical changes in every State over the past two to three years. Some murmurs of disconten were heard from the traditional technical delegates, w ho in the event were satisfied by the streams, Total Urban Water and Public H ealth and Amenity. N inety papers were presented on the fo ur platforms, as well as the keynote speakers at th e plenary session.

Poster Sessions T he poster sessions also had a new initiative, w ith the 'mini platfo rm' sessions being run so that 34 of the poster paper presenters were given a short (and strict) ten minutes in which to introduce the main points of their work. There were still some 70 posters w hich were not able to be granted such expo sure, but their standard did not seem to this reporter to be in any way inferior. It is indeed a pity that a threeday _convention has to be so rushed, and

that so many decisions have to be made by the organisers, but such is the pace of our business.

Plenary Session Another initiative, to be commended , was the appointment of four R eporters, whose onerous task it was to attend every session in their stream, and then summarise their impressions, o ut loud , to the final plenary session. T heir remarks are also summarised below.

Workshops These are always a bu sy component of an AWWA convention and , because they are specialised, the speakers and the audience relate' far more closely than in gen eral sessions. In th e workshop attended by this reporter, most of the SO-strong audience seemed to know each other by first nam es .

Michael Flynn Award for Best Papers T he Mi chael Flynn Award 1s presented at AWW A biennial conventions for the best papers based on both presentation and content.The award is named in honour of Dr Michael Flynn , who was a Director of Public Health in New South W ales and a foundation m emb er of AWWA. Dr Flynn contributed greatly to the Association until his death in 1980. At the 17th convention papers were chosen from each of the four streams and the following authors received the award: • N L Scheinkes tel for Corporate Governance and Stakeholder Expectations • P R enfrew for Performance Management-The Key to Organisation Effectiveness • I B Law for Domestic Non- Potable Reuse-Why Even Cons idei- It? • P Dillon, P Pavelic, X Sibenaler, N Georges and R Clark for Sto rmwater Runoff The papers ,,;,ill be published in this and subsequent issues of Water.


FEDERAL

CONVENTION

THE KEYNOTE ADDRESSES E A (Bob) Swinton

Modelling Achievements-Professor Jorg lmberger Professor Jorg Imberger, Director of the Centre for Water R esearch at the University of W es tern Au stralia , winner oflast year's Stockholm W ater Prize and Peter Hughes Award , delivered the first plenary presentatio n after the opening ceremony of the 17th Federal. His keynote message was that Australian science and technology in the water area is equal to the world's bes t. H e demonstrated it, with a tour de force of modelling achievements. Professor Imberger spoke about the various proj ects throughout the world that he and the Centre have been involve d in rangmg from Lake Samsonville near Brisbane, w hich is destratified by a bubble plume, to the almost circular and shallow Lake Kinneret in Israel, a coastal lagoon in Italy and the lo ng, narrow Y - shaped Lake Burragorang near Sydney. The work inves tigates the dynamic s of large water bodies of a variety of shapes and depths and mod els artificial destratifica tio n to accomplish the requisite degree of turnover with the minimum amount of applied energy. T he short paper printed in th e 17th Federal Co nventio n Proceedings outlines the main fea tures of th e projects, and Professor Imberger's hi-tech platfo rm presentation gave us the latest modelling results, in two-dimensional, moving colour. In fac t, some of the results were only a few weeks old. Display after display of colour-coded temperature profiles came up on screen , with ready explanations of the pec uliarities of seiching, cyclo nic rotation, the effects of depth and shape, and the long-wave length natu ral oscillations of each wa ter body being driven or over-ridden by wind. The lecture focused on the extension from one-dimensional models such as DYRESM to two- and three-dimensional

Lago Argentino, Argentina, site of limnologlcal investigations by Prof. lmberger on the natural convection set up by the cold ice face of a glacier that partitions the lake into two separate basins. Photo: J lmberger.

m odels. From the basics of temperature and DO to the full biogeochemistry, with the additional complication of biology, such models are being matched to real-time behaviour. However, the Burragorang models illustrated very convincingly how inadequate the u sual spot sampling program ca n be . Becau se of wind fetc hes along the valleys, the lake oscillates. As the model readouts progressed throu g h time, th ey sho we d tha t th e

parameters at a fixed point bore little relation to the bulk chemistry , so that a standard sampling program would give false results. T he use of the model to help choose the appropriate sequence of sampling to detect a trend is a possibility to be explored . The Flux Path Model , a new water quality model incorporating a statistical approach to the biological population, is proposed. R esearch and calibration of the new model is now in progress.

Lessons from the UK-Dr Bill Emery Dr W .H . (Bill) Emery is Assistant Director-General and H ead of Costs and Performance at the Office ofW ater Services (OFWAT) in the U.K. In this positi on he is in effect the 'Regulator' for the 29 wa ter and sewage enterprises and the 19 water-only businesses opera ting in E ngland and Wales, though no t in Sco tland. The privatised

U .K. system has been in operatio n since 1989 and the ' U .K. experiment' is being watched avidly around the globe. Dr Emery summarised the lessons that have been lea rned during thi s somewhat traumati c period. T he system was designed to separate the roles of the standard setters, quality regulators, economi c regulators, service

providers and customers and in Dr Emery's opinion , it has been a qualified success. Dr E m ery said , ' The monopoly water enterprises are threa tened w ith a vicious spiral. Nothing they do or report seems to convince the politicians or the public that they are running an effi cient outfit and making the best use (

WATER MAY/ JUNE 1997

25


FEDERAL of their assets.' But this has long_been the case, and the issue came to a head in the 1980s w hen the effort and capital necessary to achieve the European Directives for both water quality and sewage disposal forced the government of the day to solve the problems by selling off the public water enterprises lock , stock and barrel, and hand the problems to private en terpri se, with licences up to 20 14. OFWAT in 1989 was given the task of setting fair prices based on this need for major asset improvement program s. In the event, average bills for the services have increased by about 29% (ranging from 16% to 57%) in real terms over the six years. The highest increases were due to replacement of marine ¡discharges by treatment plants. For an average household , 160 kL per annum costs $210, and sewerage costs $250 (only slightly more, per unit volume, than for an Australian city dweller). On the other hand, due to the 1989 price levels being based on conservative judgem ents regarding risk, followed by good fortune in construction prices, as well as improved efficiency, the real returns to shareholders have been around 21% per annum for the first five years . The reaction of the media and the public to the 'fat cats' and their share options has been vociferous. In fact, this is one of the main features of the system. More and more customers view utilities as providing a commodity as well as a

CONVENTION

service, and are far less forgiving than in public ownership days .

Standards Prices were se t in 1989 and the government later adop ted the EU Directive for wastewater. The extra cost was estimated at $4 billion, but detailed costing then totalled some $15 billion. As a result, future setting of standards for quality and environmental impacts must now take into account costs versus benefits.

Customers C ustomers want improved services and environmental benefits, but are not willing to pay for them. T heir expectations have been raised by the new regime, and the high salaries and shareholder returns of the first five years make it unlikely that they will accept higher prices as justifiable.

Regulatory Processes

Companies can no longer quote their ' uniqu e' circums tances as excuses. OFWAT has developed robust models for comparative competition.

In a modern democracy all stakeholders want a say. l:ti is probably more important to get the process of regulation right and acceptable than to aim for the optimal decision. For the 1999 review of prices, OFWAT will focus on consultation, clarity in the timetable, and allow more time for representations.

Capltal

Comparative Competition

T he second ro und of prices used a capital value of abo ut one-third of that used in 1989 and , after much debate, set a cost of capital at six to seven per cent after tax. This will result in lower prices for customers.

Water services will probibly remain geographic monopolies (though there should be no legal restraint to physical competitio n). Therefore, some form of regulation w ill always be needed. OFWAT has chosen the path of comparison , but this is data-hungry, and requires consistency, honesty and openness in reporting. It has been a powerful instrument but still has some way to go . It would be in the customers' interests to make effective comparisons both nationally and internationally, so that an enterprise can demonstrate that it is ' near the frontier in terms of service level, unit cos ts and cos ts to customers.'

Benchmarking

Regulatlon Arms' length regulation is still the aim ofOFWAT, but year by year there is a steady tendency to shift to closer scrutiny, grea ter prescription and rules. Is it possible to step back, and countenance risk of occasional failure as a business enterprise strives to innovate and rely on business values to operate?

A Global Perspective-Dr John Briscoe Dr Briscoe is Senior Water Advisor at the World Bank, with responsibility for orchestrating the finance necessary to achieve water and sanitation for the populations of developing countri es. H e divided the task into two: the old agenda, which provides all people with adequate supply; and the new agenda, w hich ensures sustainability of water resources.

Achievements and Challenges In 15 years, 2000 million more people have water, either from large schemes or from small wells and 400 million urban dwellers have some form of sanitiation. However, 1000 million still do not have ready access to safe water, and 2000 million do not have sanitation. In fact, in urban areas, sanitation has actually declined from 67% to 63%. The rapid growth of cities is the major problem. As cities grow, their water resources are being engulfed by expanding development. The cost of ' new' water is often two to three times more than previous supplies. T his is aggravated by the inefficiency of the 26

WATER MAY/J UNE 1997

Dr Helmer wit h Victorian Deputy Prem ier McNamara and Dr Briscoe (I. to r.)

organisations. In M adras, for example, supply is restricted to two hours a day at low pressure. If 'normal' service levels

we re to be operated, leaks wo uld consume three times the current supply.


FEDERAL Financing

CONVENTI O N

driven the mu nicipality to provide the secondary and primary sewers.

WHO proj ec ts currently only derive less than 30% of fin an ce from the Privatisation ' users,' so there is n o ownership. D r Briscoe discussed the institutional Subsidies flow to the rich , and governments, w ho are rarely stable, do not systems and the possibilities of private allocate sufficent money for mainte- investment, ranging from 'affermage,' nance. T he poorer the coun try, the concessions and BOO to asset sales. H e compared the financial structure of the greater the distortion . water indu stry with a number of other H owever, there are innova tio n s which rem edy this. An example is the businesses, such as K-Mart, Boeing and Gram een Bank in Bagladesh , which a power company, dem onstra ting the lends development cash to organised high capital intensity of low returen on groups of women . R epayment rates are assets. For this reason , in developing countries far more investment is going over 98%. At the other end of the spectrum, in into telecom munications, power and transport than into water and waste. Chile, the water authorities have been Apart from the low cost recovery, there relieved of C SO responsibilities. is also a vulnerability to political risk. Instead , 'water stamps' are given to deserving families for the paym ent of The New Agenda their water bills. Tackling the new agenda is a huge In Co nakry, Guinea, a private challenge-the poorer the country, the company was persuaded to set up a worse the wa ter and environment system by having initial revenue guaranquality. For example, dissoved oxygen teed from the W orld Bank, enabling the levels in surfacewater have fallen over installation of an efficient service from the past ten years. Even in developed the start, thereby es tablishing a countries, adequate waste treatment is cu stom er base. However, thi s was still regarded as too expensive. Various followed by a steady transparent shift environmental protection agencies set over five years to full recovery from the standards, with no regard to where the custon1ers. ·m oney will come from. Germany, for In Orangi, Karachi , the community example, w ould need to spend $300 was 'liberated from the myths of billion to meet EU standards. Yet after government promises' and went about W orld W ar I, the Ruhr Basin successdoing the job of installing neighbour- fully improved quality by relying on hood sewage them selves, advised by a local action. This approach has been central proj ect office. Their success has adopted by the French , who have, in

Safe Water-Dr Richard Helmer Dr Richard H elmer, the C hief of the W orld H ealth Organisatio n 's Urban Environmental Unit, provided a global on water-related h ealth . view Acco rding to Dr H elmer, wa ter resources will be the ultimate controller of population in the world, w hatever the particular scenario developed o n a computer model. Safe water is still beyond the reach of most of the world's present population. For example, in 1990, about four million children died of water-brone illness, and about half the population of developing countries at any given time is suffering fro m a range of bo th bacterial and parasitic water-borne diseases. Yet only fo rty litres per person a day of safe water would provide both quality of life and human dignity. There are many differences across the world , ranging from too much water use (i. e. the self- inflicted rise of watertables by over- irrigation) to the grow th of m ega-cities, w ith an estimated sixty per cent of the world living in such cities by 2025, w here

prov1s10n of water is considered a cheaper and high er priori ty than disposal of sewage. Eighty per cent of Asia relies on groundwater and it is being seriously overdrawn , as well as being polluted. A prominent example is Beijing, w here the watertable recently fell four m etres in one year. In Bangkok, chloride has risen to 600 mg/L due to saline intrusion . M any groundwaters suffer from their chemistry. Iodine deficiency is endemic in mountainous areas . Some 200-300 million people are manifestly affected. Fluorosis affects more than 50 million in Africa, India and C hina. Arsenic affects populations in M exico, C hile, C hina and India. Anthropogenic pollution has led to dangerous nitrate and pesticide levels. T his is n ot limited to developing countries. However , microbiological risks dominate and although industrialised nations seem to fo cus more on the chemical ri sks, they are minor compared to the microbiological risks. C hlorine is still the most cost-effective

effect, a river parliam ent that trades off standards ve rsu s costs but locates responsibility for action at the local level.

Water Trading In arid zones, where water resources are limited , trading in rights is developing. Althou gh so fa r only a sm all percentage of rights change hands each year, the economic and even environm ental effects are beneficial. Australia is an example of t?e design of a well regulated water market.

Conclusions The Dublin Statem ent is an influential statem ent of three principles: • the ecosystem princple that managing w ater is a holistic exercies • the institutional principle that participation and ow nership is vital and that wom en have a vital role • the economic principle that water is an economic as w ell as a social good. T o solve the awesome task of both agendas, sound fi scal sen se is vital. Economic and environmental enhancem ent must go hand in hand, and finally, it is the affected people who have to make the decisions, albeit based on sound technical advice. Dr Briscoe regards Australia as a world leader in water management and is of the opinion that ,w e do not do as much as w e should in exporting our technical experti se. W e could w ell compete with the U .K . and France on the world market.

control , and the challenge is to minimi se the by-products w ithout compromising the disinfection . The difference between the risks, both in the time factors and the prognosis, is so wide that the balan ce cannot be resolved scientifically. The function of the legislator is to understand better the intricacies of the risk assessment process and its inherent probabilistic nature, in an atmosphere of uncertainty. In a wider scenario, the rapid industrialisation of Asia and South America is not being matched by corresponding efforts to safeguard environment quality and ecological balance. At the sam e time, to feed the cities, inten sified agricultural production is leading to salinisa tion . It is es timated that for every ten hectares of land brought into rice irrigation, some three hectares are lost. Although pollution of rivers and lakes is obviou s, the increasing pollution of groundwater is a hidden process for which future generations will have to pay dearly. W ater will be the ultimate control of the human population. WATER MAY/ JUNE 1997

27


BUSINESS

PERFORMANCE MANAGEMENT THE KEY TO ORGANISATION EFFECTIVENESS P Renfrew Abstract An effective organisation is dependent on understanding and managing all the parameters that have an impact on strategic obj ectives . This requires 'the ability to work 'on' the bu siness rather than 'in' the bu sin ess . Su ch an ability is based on timely feedback that provides a balanced perspec tive on organi sation functioning and is used fo r active managem ent and informed decision-making and lea ds to continuous improvement.

Introduction An effective organisation needs to address the performance expectations of its stakeholders and develop organisation capabili ties to enable strategic obj ec tives to be achieve d , whilst maintaining operational and financial viability. Viabili ty is dependent on external stakeholders w ho give the organi sation its ' mandate to operate.' A sound mandate requires responsive ness to customers, suppliers and community which is based on three characteristics : â&#x20AC;˘ integri ty-the basis for sustainable relation ships â&#x20AC;˘ relationships, which enable capabilities to be deployed â&#x20AC;˘ capabiliti es, w hi ch underpin an

40

WATER MAY/JU NE 1997

orga nisation's ability to compete. M anagem ent and employees base decisions on available data. In the past this data has been primarily focu sed on the operational and financial status of the organisation and has been often res tri cted to se nior manage ment review. A broader range of data , based on weighted key performance indicators, provides the basis fo r more informed decision- making . This lea ds to th e active managem ent of organisatio n param eters and stakeholder relationships that will add valu e to organisation effec tiveness. Organisations are often swamped with data . Effec tive man age ment is based on the ability to concentrate on w hat is relevant. R elevance is based on the organi sa tion's vision and values, the articulation of what drives the organi sation and distinguishes it from others, the guiding principles and source of competitive advantage . The road map to achieve the vision is se t out in the strategy and business plan which , in turn , form the basis fo r performance management. This enables informed decision-making and allows the vision to come alive.

Peter Renfrew won the Michael Flynn Award for t his pa per in The Water Business: Emerging Issues stream of the 17th Federa l Conve nt ion

Performance Management If organi sation s are to increase their effectiveness, they must understand and manage th eir critical stakeholder relationships and develop capabilities to add ress strategic obj ectives . Stakeholder/Organisation Capability Perspective. T o understand and

manage an organisation , the stakeholders that have an impac t on the organi sation need to be identified, their performance expec tations defined and critical stakeholder relationship s managed. Stakehold ers include, but are not restricted to , shareholders, managers, staff and customers/clients. They could also include finan ciers, suppliers, contractors, competitors, the community, lobby groups, m edia , government, politicians and unions. The starting point is to clearly identify those stakeholders that have an impact o n th e organisation. The understanding of these relationship s is enhanced through a sys temic model w hich provides an interactive perspective on stakeholders. An organisation is dynamic and its relationships need to be understood in such terms (see Figure 1). Each of the criti cal relationship s needs to be understood ahd managed. This requires a regularly measured key performance indica tor which addresses the underlying basis of the stakeholder relationship. The organi sation's capabilities also need to be understood and managed.


Organisation capabilities address all the parameters that have an impact on the organi sation's ability to achi eve its strategic obj ectives . These can include financial issues, infrastructure, technology, w orkforce competence, operational pro cesses, managem ent style, w ork environmen t/culture, client relationships, marketing and sales. Alignment. The capabilities that have an impact on the organisation need to be identified and managed in relation to the current level of organisation functio ning and the importance or criticality of the organisation's impact. What is sought is alignment , so that the o rga ni sati on 's level of fun cti o ning matches the importance or impact of th e capability on the o rganisati on 's strategic obj ectives . A capability that has a high level of impact requires a high level of functioning. A capability with a low level of impac t requires a lower level of functioning. This alignment process can be presented as a matrix (see Figure 2). The high relative valu e capabilities coupled w ith a superior level of fun ctioning provide the basis for comp etitive advantage. These are indica ted at (A) in Figure 2. High relative value capabilities with a level of functioning that is deficient (B), need improvem ent . T his is achieved through active management. C apabilities with a relatively low impact on the bu siness, but high levels of functioning are in surplu s (C). Th ese could be overresourced and increased efficiency may be obtained by reducing the level of resourcmg. Active Management. It is costineffective to seek high levels of organisation functioning to address all capabilities. Effort needs to be expended in relation to the value that can be added . Those capabilities that are aligned (the level of functioning is proportional to the impac t on the organisation) are monitored. No improvem ent in performance is sought, but current levels of fun ctionin g need to be maintained. Those capabilities that have a level of impact higher than the current level of fun ctioning (defi cient) n eed to b e actively managed. Active management requi res specific initiatives that result in a change to the ways the organisation functions. Capabilities that are 'defi cient' can be managed by increasing the level of functioning or decreasing the impact. D ecreasing the impact requires consideration of the organisation's products , services and customer/client delivery. This implies a decision about the scope of operations. The level of functioning can be increase d through ac tive m anagem ent , w hich could involve

addressing internal capabilities, or outsourcing those that are not core, but are required to mee t product/service delivery needs.

â&#x20AC;˘ m andate to op erate, w hi ch 1s captured in safety, environment and community measures â&#x20AC;˘ ability to compete, which is dependent on the competence of the workforce, the internal dynamics and cultu re of the company and the effective managem ent of risk â&#x20AC;˘ business outcom es that are directly linked to the operational and financial requirements of tfie organisatio n.

Key Performance Indicators All areas to be actively managed, and the high impact capabilities that are aligned , require a key p erformance indicator. A key performance indicator enables data to be made available so that the capability can be understood and managed. The key performance indicators need to address critical stakeholder relationships and organisation capabilities. T hese are combined to create a balanced perspective on the organisation. Such a balanced perspective has recently been developed for BHP Petroleum and an example of the company- w ide key performan ce indi cators is detailed below . The key performance indi cators address the company's :

Weighting M anagement and employees cannot successfully seek organisation improvement across a large range of issues . They are all bu sy getting on with their operational job requirem ents. Priorities need to be set based on adding value to the organisation. Priorities are indicated by weighting the key perfo rmance indicators. The weighted key performance indicators enable organisation effectiveness to be assessed. If the ac tive management has been

Defi ciencies Need to Develop /

/

Alignment

/

Mandate

Compete

Business

Surpl uses Over Resourced

Strategies and Principles

Performance Measure

Safety/ environment

LTIFR # fatalities Spills (volume and number) Emissions discharge Hazard register

Community

Media monitoring

People

Job fit index Organisation climate index

Risk management

Risk index Risk uncertainty index

Optimise existing business portfolio rationalisation

NOPAT Cash flow ' ROC% Internal client satisfaction (team-focused resource)

New business development

NPV Market share Revenue

Figure 3 Key performance indicators WATER MAY/ JUNE 1997

41


BUSINESS

Figure 4 Performance management framework

--------------DO-------------~

I

Performance---------+ Measurement

l

ACT

Continuous Incremental Improvement Cycle

CHECK

Change Behaviour--- - - - - - - Feedback

' - - - - - - - - - - - - - - P L A N - - - -- - - - - - - - - -' Figure 5 Continuous improvement

Job Description (1)

!

l

Evaluation Score

Competencies

Key Accountabilities

(2)

(3)

(4)

• Competence development and acquisition • Coaching • Mentoring • Training • Selection and Hiring

• Job • Orientation • Design Process Reengineering

INDIVIDUAL EMPLOYEE

ORGANISATIONAL PROCESS COMPETENCE APPLICATION

----..

+ Establish internal relativities for pay purposes

At the right cost

applied In the right way

lndlvldual "Value"

Base Pay

Figure 6 Understand ing and managing jobs

42

WATER MAY/ JUNE 1997

Key Result Areas (Outcomes) (5)

+ • Performance Measures • Weighted Assessment

Timely Feedback

with the right · · · · · · competencies

Labour Market Positioning

----..

effec tive, the weightings need to be reviewed . T he reassessment of stakeholder relationships and organisation capabilities resulting in revised weightings or priority setting should take place annually. T he key performance indicators and their weightings form a framework for understanding bu siness unit/ team contribu tion to the overall organisation. This is illustrated below. The weightings applied to a business unit/team vary from the overall orga);lisation and reflect the anticipated contri ution and current level of functioning (capability) of the business unit/ team. Figure 4 illu strates the nee d to understand the company's ability to address the overall goals, strategies and principles thro ugh a balanced set of performance measures (see Figure 3). Each business unit/ team will also have a se t of measures, critical key performance indicators. These are used to assess business unit/ team performance and co ntribution to the company. The reporting at the company level is restricted to critical key performance indicators and these are the same as, or directly impact, the company performance measures. T he bu siness unit/ team may have a number of other specific key performance indicators that provide insight into the management of the processes that res ult in critical key performance indica tor o utcomes. T h ese bu siness unit/ team key performance indicators are not reported on at the company level. Individual contribution assessments are based on the critical and specific key performance indicators of the business unit/ team , but are often focusing on target achievement and milestones. T he overall obj ective is to provide a clear line of sight between individual, business unit/ team and company performance. To facilitate such a process, a bonu s or shared rewards program can be used that foc u ses on the achievements of the company and business unit/ team .

ORGAN ISATION OBJECTIVES

resulting In the right outcome

Work Unit/Team Performance

Bonus

An ann ual performance review process is ineffective. T imely feedback of data is required on a weighted , all key performance indicator basis (balanced perspective) so that decisions leading to more effective ac tive management can be made. As a minimum , such fe edback and decision-making should be at least quarterly . T he quarterly review forms part of a co ntinuou s improvemen t process (see Figure 5).

Business Plan The quarterly process of reviewing the weighted key performance indicator data results in the refinement of the financial and business plans. These are


BUSINESS 'live' documents, not static annualised plans. The annual acco untable performance requirem ent of a business unit/ team or the organisation as a whole is the weighted key performance indicator , not a financial or business plan . Financial and business plans are process tools that enable the active managem ent program to be articulated , with milestones, timetable and respo nsibilities clearly defined. These need to be adjusted and refined on the basis of qu arterly feedback . Unle ss the dynami c process of reviewing the feedback data leading to financial and business plan refinement is carried out, the performance management program will not res ult in an effective organisation.

tio n purposes, but.this should be bonusbased and applied at the overall organisation and/o r business unit/ team level. An effective organisation is dependent on the coordinated , collaborative efforts of the workforce. These are assessed through the weighted key performance indicators. T he meaningful m easurem ent of such outcomes at the individual employee level is difficult and often meaningless. Employee contribution can be used to determine base pay and should be centred on 'value' to the organisation. Employee 'valu e' takes into account co mpetence and ac tual co ntribution which is assessed on the basis of key accountabilities. This is illustrated in Figure 6 in terms of understanding and managing jobs.

Performance Recognition and Reward

Conclusion

The weighted assessment of performance can be recognised for remunera-

The effective organisation reqmres alignment between stakeholder expectations, o rga nisa tio n capabilities and

strategic objectives. This requires an integrated approach to understanding and actively managing the organisation that is based on data. The timely, at least quarterly, provision of weighted key performance indica tor data forms the ba sis of a continuou s improvem ent program . Performance achievement can b e recognised w ith resp ec t to a remuneration program, effectively co mbining an organisation, business unit/ team bonu s with individual employee 'value' -determined base pay .

Author Peter Renfrew is Principa l Consultant of the RYM Co nsulting Group Pty Ltd, with expertise in. all aspects of human. resource management. H e has degrees in both Arts and Science with majors in psychology and economics and a Diploma of Education. H e is a member of the Institute of Compa ny Directors.

WATER ENVIRONMENT MERIT AWARD Margaret Metz The W es tern Au stralian Water Corporation won this year's AWWA W ater Environment M erit Award for its Albany land disposal wastewater site, the Albany tree farm. The proj ect , to uted in parliament by Dr H am es, the WA Minister for W ater R esources, as 'a shining example of government and the community working together to solve a problem ,' and 'a pacesetter in wastewater reuse,' is the first agroforestry scheme for eilluent dispo sal in Western Australia. The merit award was presented at the AWWA 17th Federal Convention in Melbourne in recognition of the contribution the project made to alleviating an environmental problem in the region , the innovative practices used in its ongoing operation and the high level of community support it continues to eruoy. Following a commitment that trea ted wastewater wo uld no longer be disposed of in the harbour, the land dispo sal wastewater system for Albany began operation in January 1994. It involves the trickle irrigation of a plantation of 500 ,000 ' thirsty' Tasmanian blue gums. T he plantation is 13 km from Albany and more than 3,000 kilolitres of wastewater is pumped to it daily . The tree farm will begin selling timber in 2002 and ha s the capacity to m eet

Albany's efflu ent reqmrements until at least 2020.

Tasmanian Water Environment Merit Award Ed K!eywegt, Water's Tasmanian correspondent, has reported that entries expressing interest in the Tasmanian Environment M erit Award were received from a broad crosssec tion of organisations in the Tasmanian water scene, with industry, suppliers, Menno Henneveld (right) accepting the Water and consultants Environment Merit Award on behalf of WA Water co ntrac tors all repreCorporation from AWWA President, Mark Pascoe sented. Like the national award, the Tasmanian Environment An annual trophy, designed to provide M erit Award aims to raise public aware- the recipient with peak industry recogness of the environmental contributions nition as a leader in the water enviro nof organisations and encourage innova- ment, will be aw arded to the ,winner. The nominations cover gold mining tion and co ntinuing, su stainable wa ter reuse, fish management, on-site environmental improvement. The Tasmanian award also aims to was tewa ter trea tment sys tem s, foo d provide annual recognition of an indu stry by-produ ct re u se, mining environmentally significant Tasmanian industry tailings m anage ment and proj ect, product, service, or initiative timber industry wa ter reuse. undertaken du ring the past 12 months. WATER MAY/ JUNE 1997

43


ENVIRONMENT

DEVELOPMENT OF AUSTRALIA'S

NEW HORIZONS OCEANS POLICY In March 1997 Federal Environment Minister Robert Hill announced $6.5 million in new initiatives aimed at ensuring that Australia's marine biodiversity is conserved and managed sustainably. The initiatives coincide with the development of an Oceans Policy being developed by the Federal Government that is due for completion in 1998, the International Year of the Oceans. The Commonwealth Government has published a policy consultation paper, Australia's Oceans: New Horizons, to assist in consultations with State, territory, and local governments, peak bodies and organisations and the general public on the broad framework and associated actions that should underlie the Oceans Policy. Although submissions from the community closed at the end of April, readers will be interested in this edited summary, which concentrates on water and wastewater aspects. Summarised by Margaret Metz . The Vlabillty of Our Marine Environments The declining state of our marine water quality and in particular the impac ts from land based so urces of marine pollution is seriously affecting the viability of our marine environments in som e areas, particularly in coastal areas under pressure from urban development. M arine organisms may be affected by a range of discharges and emissions including nutri ents and sediments, heavy metals, organochlorines and litter. Most of these, in the order of 80%, enter the sea from the land , from both point sources such as pipes and drains and diffuse sources from catchments, the atmosphere and sea-based sources.

Control of Urban, Industrial and Agricultural Wastes Activities that pose a threat to the marine environment include the effects of nutrient and sediment runoff created by inappropriate land development . Each year around 10 ,000 tonnes of phosphorus and 100 ,000 tonnes of nitrogen are discharged through sewage, much of which finds its way into the marine environment. Elevated nutrients

~ - _------· j

may cause eutrophication , the excessive growth of algae, which may smother other organisms. Improved managem ent of waste discharges (including effluent, urban and agricultural runoff and trade wastewater) into the marine environm ent is a major challenge facing Australian governments and is essential for maintaining and improving marine and es tuarine water quality, coastal habitats , public health, recreation and visual amenity. The Oceans Policy will address a range of issues which may include: • the wide range of sources of marine pollution (land, sea and atmospheric) • nutrient flows from river catchments • the environmental performance of sewage and stormwater systems • national water quality standards • ballas t water strategies and hull fouling • oil spill response capacities • gaps in m anagement r~gimes for marine pollution, for example chemical, mineral and bunker fu el spills and shipping and barging operations • marine debris including impacts from vessels, recreational and urban sources • the deep sea dumping of ships, structures and other materials. WATER MAY/ JUNE 1997

45


ENVIRONMENT Coastal and Marine Planning There will be a $6.4 million boost to coas tal planning efforts through the crea ti o n of the Coastal and Marine Planning Program. This program will provide funds to projects prepared by local and State governments that will res ult in the development of integrated, regionally based, strategic plans for the protection of Au stralia's coas tal and marine environments. N um erous reports have identified ad hoc decision making along our coasts as one of the major causes of environmental degradation. This program will aim to ensure that the three tiers of government are working together and that . decisions are made in a strategic way that takes account of the local environment and the recrea tional, heritage and aesthetic values of the coastline. Key obj ectives of the program will be to minimise the impacts of ad hoc and uncoo rdinated develo pment in the coastal zone and to combat the degradation of coastal and marine environments thro ugh increased ru noff, sewage, stormwater and litter pollution , beach erosion and increased nutrient flows. State and local governments will be invited to nominate suitable projec ts for joint Commonwealth/State/local government funding. Key o utcomes of projects could include: • a m ultiple use strategic managem ent plan • a coastal wa ter quality management plan • identification of areas su itable for development on an ecologically sustainable basis • identifica tion of areas of high conservation value • plans of ac tion for reducing marine pollution • establishment of strearnlined decision making processes.

the R epublic -of Korea, Singapore, T hailand , Vietnam and the People's Republic of C hina . The conference will develop an East Asian Seas Action Plan that will identify cooperative ac tions needed to address land-based sources of marine pollution such as sewage, oils, nutrients, sediment and litter. Marine pollution forms a major threat to the health of our coasts and oceans and , w hile often much of the public and media focus falls in events such as oil spills, the reality is that about 80% of marine pollution is sourced from land-based activities.

Marine Science and Technology Plan Improve d scien tifi c knowledge, understanding and an associated monitoring and information system will underpin both the sustainable use and protection of the ocean environment and provide the capability to recognise, predict and manage change as it occurs. This will be addressed through the development of a Marine Science and Technology Plan w hich will be integrated with the Oceans Policy. A scoping paper for the Marine Science and Technology Plan is bei ng developed and is expected to be ready for public release in April 1997. Through the Marine Science and Technology

Plan, the Oceans Policy will address a range of issues w hich may include: • articulati o n of Australia's m arine science and technology needs and how such needs can be funded over the longer term infras tru cture • institutional and arrangements • information to suppor t decisionmaking and marine management • integration of marine- related data • the adequacy of existing databases • national mappin use and resources survey • national monitoring and data collection • development of reliable indicators • a m ultidisciplinary approach to marine science and other areas • Australia's expertise and capabilities in ocean-related science, technology, research and engineering.

Submissions If yo u wo uld like a copy of the scoping paper for the M arine Science and Technology Plan or wish to make a submission concerning the issues arising from its development, please contact Dr Ralph J ensen , Science and Technology Policy Branch , Department oflndustry, Science and Tourism, GPO Box 9839, Canberra ACT 2601, tel. (06) 213 6403, fax (06) 213 6394.

SPECIALISING IN ENVIRONMENTAL SERVICES ..,.. Environmental AudiVSite Investigations ..,.. Contamination Assessment & Remediation ..,.. Environmental Risk Assessment

International Issues

..,.. Hazardous/Industrial Waste Management

Another initiative is renewed international efforts to control land-ba sed marine pollution . Througho ut Australia and So u th-Eas t Asia, mos t of the pop ulation is concentrated within the coastal zone. Much of the coas tline in these areas has been significantly altered by urban, industrial and port development. M arine pollu tion does no t recognise national boundaries. T he pollution of one country can often end up being the problem of another, w hich is w hy international and regional ac tion is an important componen t of addressing the issue. In Cairns in April this year Australia will host a conference of South East Asian coun tries including Cambodia, Indonesia, Malaysia, the Philippines,

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46

WATER MAY/ JU NE 1997

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ENVIRONMENT

A NEW SCREENING TECHNOLOGY FOR THE ENVIRONMENT RA Jago Abstract A non-blocking screening device w hich operates at high flowrates has been developed by CDS Pty Ltd (previously known as Pollutec Operations P ty Ltd). The device originated in a local invention, first trialled in Ro sebud, Victoria, to protect the local beach. It traps almost all the water-borne litter w hich enters, together with a high proportion of sinkables, including vegetative matter, coarse sediments and solid litter. CDS units have now been installed by water authorities in several Australian states to protect local waterways or receiving waters. An operational history has now been built up on many of these units and data is being accum ulated on their performance and function. An unexpected benefit in large-scale units is that most of the trapped solids are less than the aperture size of the screen used. This paper presents some of this data and evaluates the contribution of the CDS device to protecting the environment.

Key Words Screening, sediments, litter, gross pollutants, gross pollutant trap, urban di:ainage, stormwater

Introduction The litter and debris associated with stormwa ter runoff is becoming an environmental problem worldwide . With the tightening of environmental standards, authorities are being increasingly required to address the issue of cleanup of stormwater before discharge, but are finding that conventional entrapm ent methods suffer severe shortcomings w hich include incomplete capture, easy blocking and the need for frequent cleaning.

The CDS Pollution Control Device T he Continuous De fl ective Separation (CDS) technology is a gross

pollutant trap w hich uses balanced fluid flows to produce an effective separation of a fluid and entrained solids. By setting up a continuous, circulating flow of influent over the face of a screen , this controlled flow, together with the low head differential across the screen , keeps it free from blocking and permits the trapped solids either to float on the surface or settle into a sump where they can be periodically removed. The operating principle is the use of indirect rather than direct screening. Whereas direc t sc ree ning requires suspended solids to be retained on the screen w here they build up and restrict the screen function, indirect screening keeps the screen clear because suspended particles are deflected away while the screened fluid passes through. At its simplest, the unit comprises an approximately cylind rical tank with sp ecially shaped inlet and o utlet channels to lead the water smoothly to and from the unit (see Figu re 1). A cylindrical screen is loca ted in thi s tank , and the influent is led into this. As the incoming fluid passes across the face of the screen, solids contained in the stream move away from the screen toward the centre of the unit, w here they either float to the top and are retained w ithin the separation chamber, or spiral downwards to be collected in a sump , w here they remain until removed. T hey cannot be resuspended by subsequent flows . Settleable solids are removed from the influent according to their concentration , size and density. Separation of floatables is close to 100%.

Design, Construction and Operation CDS units are designed according to sp eci fi c storm eve nts, for example three- , six- or twelve-month events, or occasionally up to one in five yea rs. T he choice of the average recurrence interval for design purposes depends on many fac tors, including rainfall, nature of the

catchment, landuse and topography. A weir is sized appropriately and placed in the inflow channel to ensure that flow into the unit is according to design. If the discharge in the pipe exceeds the design capacity of the CDS , the unit is bypassed and the excess water flows over the weir. Installation is easy because it uses existing grades. No additional mechanical energy input is required because the natural fall of the site is exploited to drive the C DS effec t. No suppo rt infrastructure is req uired , and apart from periodic clea nout no o ther maintenance is usually required. Large units are usually of concrete cons truction and are cast in place; smaller units may be either precast in concrete or fabrica ted from galvanised or stainless steel. Screens and associated components are made of stainless steel, but for applicatio ns involving fats and greases the¡se m ay be plastic-coated to minimise adhesion. Like any other hydraulic structure, a CDS unit will create some head loss in the ex1stm g sys tem. H ead losses observed have been sm all , but if for a given case they are con sidered too large, then ei ther a smaller unit must be co n sidered or the system m u st be modified. Such cases do not imply that the CDS is producing the observed head loss itself, but generally indicate som e defici en cy in the hydraulic system . Space requirements for units are small. For example, a unit handling flows of 1 m 3/sec can have a surface footprint of3 m diameter, with a corresponding below-ground footprint of 4.5 m diameter. Units are us ually housed underground with security covers for cleanout, and thic:refore have minimum visual impact. Solid s removal sys tems vary, depending on client requirem ents. Units may be fitted with a removable basket or screw co nveyor, or may be pumped o ut using an eductor. Other units are configured to discharge solids WATER MAY/ JUNE 1997

47


ENVIRONMENT thro ugh a dump valve in a conical b ase, while very large units can be emptied with a mechanical clamshell bu cket.

Installed Stormwater Units Units with flowrates up to 3.2 m 3/s have now been installed and even larger ones are currently being designed . Such large flows may either be treated by a single unit, or split between several units to facilitate modular installation and accommodate budgetary requirements. To date, there are twenty-five units currently installed in N ew South W ales , ten in Victo ria, fo ur in South ustralia, two in T asmania, three in Queensland , two in T asm ania and one in N ew Z ealand .

¡v1ctorla M elbo urne W ater has installed a 1 m 3/s CD S unit in a monito red catchment area of 50 ha at Coburg in M elbo urne (Allison , W o ng and M cM aho n , 1996) . The unit treats runoff from a combined residential and light commercial area, separating urban litter on a continuous basis, before the cleaned stormwater is discharged to a local waterway. The unit was cast in situ in co ncrete. B o th storm flows and captured litter are routinely m onitored at this site . Several cleanouts have n ow been co ndu cted , all of w hich show that vege tation was a co n sistently high proportion (typically 65-85%) of the materials removed . Of the rem aining materials, plastics were by fa r the greates t compo nent , follo wed by pap er produ cts. Other pollutants trapp ed included metals, grits and sediments. At a recent cleanout, 8 m 3 of this kind of litter was removed fro m the unit, following a collection period of seven m onths. These are materials w hich would otherwise have ended up in the nearby waterway, lea ding to unsightly floating debris as well as siltation of the creek . T he odour of decomposing vegetative matter is a further disagreeable effec t which has been averted. The Federal Airports Corporation has recently installed a smaller C DS unit next to M elbourne Airport , sited on a 217 ha area comprising most of the sealed and unsealed areas of the airport, including runways and operations areas . At a recent cleanout of the unit, 4.5 m 3 of wet solids were removed from the sump after a collection period of 2 .5 months. T he solids comprised mostly leaves, with the usual complem ent of sediment, drink cans , plastic film and containers, sticks and unclassified item s. In suburban M elbourne, the ultimate destination of all such litter is Port Philip Bay. In this single case, the CDS unit has reduced the loading on the Bay 48

WATER MAY/ JUNE 1997

by an estimated 20 tonnes per annum. The original unit at R osebud has op erated perfectly and is emptied by the local council as occasion demands by lifting the sump basket by crane (see Figure 2).

New South Wales In N ew South W ales the C DS technology has b ee n enthu sias tically, embraced with some 17 units now installed throughout suburban Sydney, and seven more either under construction or awaiting construction . At Balmoral, the Mosm an C ouncil has been operating a C DS unit since N ovember 1995. O ver its short life of 15 months, this unit has captured over 30 to nnes of organics, se diment and litter w hich w ould otherwise have ended up o n Balmoral beac h o r elsewhere in the H arbour. The unit has bee n emptied five times to date (cleano ut amounts on these occasions were 4, 4 , 3.5, 11.5 and 6 tonnes respectively). T he nature of the solids remove d fro m these uni ts depends of course on the catchment. T he distribution of solids from the Balmoral unit is u sually approximately 60% organic material, 30% silts and sediments and 10% litter. On o ne occasion , however, there was a road failu re in the catchm ent area and the amount of sediment caught ro se to approximately 60% in a total load of 11. 5 tonnes. A C DS unit has been in operation at Baulkham Hills in Sydney since mid 1996. From cleanout data, this unit is also collecting solids at the rate of about 2 tonnes per month . As with other city suburban units, the rn.akeup of these solids has been estimated to be approxim ately 60% organic m atter, 30% sediment and 10% litter.

Figure 1 Schematic of the CDS unit

Figure 2 The sump basket being emptied

Figure 3 Floating litter from CDS unit

South Australia Of special interes t is the C D S unit installed to protect T he Patawalo nga at Brighton, a suburb of Adelaide. This unit has a design flow of 3.2 m 3/sec and is sited to serve a large urban catchment. Shortly after installatio n , two significant thirty-minute rain events were recorded following an initial dry spell. At

Figure 4 A high proportion of solids collected from urban runoff is vegetation and silts


ENVIRONMENT the first cleanou t of this unit a record 15 tonnes of solids was removed from the sump. This example highli ghts the vah.1 e of CDS gross pollutant trap application even in a dry climate, w here litter acc umulates on the ca tchment but is washed into the stormwater drains as soo n as rain fa lls. Unfortunately no details are available of the composition of the solids captured.

It is particularly difficult to carry out remove gross solid s. T he absence of a representative analysis of the trapped such pre-trea tment has often caused solids, as the entire contents of a sump long-term maintenance problems, would have to be sampled . The results resulting in many urban we tland that follow refer to composi te 'grab' systems becoming a lo ng-term liability samples taken randomly from the to the co mmuni ty (Wong, 1997). contents of a sump. The u se of gross pollutant trap s It has been observed that w hen and/o r sediment basins is considered mixed solids are present, a feature of the technology is the capture of sediments essential in sustaining the effectiveness with particle sizes far smaller than the of wetland systems in stormwater polluCaptured Solids aperture size of the screen used (usually tion control. Analysis of cleanou t data from a 4.7 mm opening). Prescreening of Potable Water. Figures 5 and 6 show cumulative operating units shows that a high Potable water, for example from reserplots for grab samples of particle size proportion of solid s collected from urban runoff is vegetation and silts, the sediment solids taken from operating voirs, requires prescreening before it is proportions varying with sites and the CDS units in Sydney. In one case, all of treated , in order to remove gross pollunature of the runoff (see Figures 3 and the sediment particles are less than the tants w hich reduce the efficiency of the Although experiments conducted on a screen aperture of 4. 7 111111 . In the other, trea tment process. model CDS unit indicate that only a over 90% of the sediment particles are In Situ Treatment Prior to small percentage (10% ) of sub-l 00Âľ m less than this size . Discharge. Responsible companies are No completely satisfactory explanaparticles would be retained by even an 0.6 mm aperture screen , analyses from tion exists for this res ult, although it is now seeking to implement a 'zero effiuoperating units, w hich are much larger likely that sediment particles are inter- ent discharge' policy, whereby all than the exp erimental unit , re turn acting wi th oth er materials such as wastes are treated on site pri or to leaves and becoming attached to them. discharging clean wa ter from the site . surprising results. For example, weeds T h e CDS technology ca n assist in with clay particles in implementing this policy by reducing 100 . - - - - - - - - - - - - - - - - - - - , - - - , their roots would tend the loading of solids, whether sediments to sink into the sump or biological wastes, in the stream to be 90 with the clay particles trea ted and m aking subsequ ent treatintact . These wou ld ment operations m ore efficient. 80 then report in a later One example of this is the current particle size analysis as a 70 interest in tru ck wasli.down fac ilities, high percentage of w h ere operators are limiting the retained fines. 60 The greatly improved discharge of sediment and vege tative capture performance of m aterials to the drains by first screening 50 s CDS units over expecta- out as much of the solids as possible. tions based on the 401--~-~~~~-~~~~~-~~-.-~......-1 Wastewater Screening. Effluent behaviour of individual 10 0.1 0.01 polishing in wastewater trea tmen t particles implies that Particle Size (mm) capture rates in practice plants is commonly applied but with depend less on screen varying results. M any plants attempt to aperture than on facto rs reduce the remaining solids to acceptFigure 5 Cumu lative particle size distribution of grab such as catchment type, able levels, but rely on conventional sample of sediment taken from operating CDS unit in materials present, parti- (direc t) screening. Small obj ec ts such as Caringbah , New South Wales. S denotes screen cle distribution and size, co tton buds are particularly difficult to picture (short way direction) and w hether or not remove by this means, yet are removed these are agglomerated. efficiently by CDS at high flow rates. The improvem ent to beaches next to New the o utfa lls would be immediately Environ mental 100 apparent to users if the technology were Applications 90 N ew environmental more widely applied. protec tion application s the CDS are for cons tantly being suggested and examined for feasibility. This sec tion highlights a few of these.

80

70

60

50

40 0.01

0.1

10

100

Particle Size (mm)

Figure 6 Cumulative particle size distribution of grab sample of sediment taken from operating CDS unit in Mt Druitt, New South Wales. S denotes screen picture (short way direction)

Wetlands. The effectiveness and aesthetics of wetland sys tems 111 stormwater pollution control are enhanced if some degree of pretreatment of stormwater inflow is undertaken to

References Allison, R.A., Wong, T.H.F. and McMahon, T.A. , (1996) Field Trials of the Pollu tec Stormwater Pollution T rap, Water, 23, 6. Wong, T.H.F, (1997) Overview of Solutions to Problems caused by Urban Stormwater, Proceedings of the Urban Stormwater Management Workshop, 17th Convention of the Australian Water and, Wastewater Association, Melbourne.

Author Dr Richard Jago is R esea rch and Development Manager of CDS Pty Ltd. H e is an applied scientist with experience in CSIRO and industry. WATER MAY/ JUNE 1997

49


ENVIRONMENT TECHNICAL NOTE

ATTENUATION OF LANDFILL DISCHARGES IN SANDSTONE STREAMS: A RESEARCH PROJECT OUTLINE M Petrozzi Introduction In the Sydney region , landfill run-off and leachate may enter streams flowing through the deeply incised sandstone terrain . Preliminary inves tiga tion s (Petro zzi 1994) sugges t that such channels have the capacity to partially attenuate o r ' trea t' contaminant discharges, since they generally consist of a series of discrete pools separated by bedrock reaches. This proj ect at the D epartment of Geography, University of Sydney, is supported by W aste Service N SW. Aspec ts are being carried o u t in conj unction with the A ustralian Nuclear Science and T echnology Organisation.

Project Alm The central aim is to inves tigate channel and hydrological controls on

the conveyance and in-stream attenuation ofl andfill discharges in the discontinuo u s, sand sto n e channels of the Sydney region. Investigations will cover runoff, channel morphology and downstrea m distribution of in-channel water sto rages, as well as dow n stream contaminant conveya nce and mchannel attenuation.

Landfill Runoff Stream gaugin g will provide an understanding of runoff volumes and coefficients and hydrographs discharged from landfill sites. T he effect of channel m o rphology is being inves tiga ted thro ugh flood routing coupled with flow recording in dow nstream reaches . Stream discharge is being m easured continuously for one year dow nstream of three landfills. Two sites-Lucas H eights I and II-are located in the Mill C reek catchment, w hich drains into the Geo rges River estu ary . Kimbriki R oad landfill is located in the

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D eep Creek ca tchment, w hich drains into N arrabeen Lagoon. D ischarge is also being monitored in the lower reaches.

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Channel Morphology T his will determine the in-channel storage volumes and characterise the bedrock reaches in the study streams. Survey points are located along the channel long profile, as well as stream bank, alluvium and valley- sides. Particular attention is being given to pool ou tlets w hich control the sto rage of water above low -flow levels (Petrozzi, 1994; Petrozzi & W arner, 1996).

Contaminant Conveyance and Attenuation T his study fo cuses on the three m ain leachate characteristics: • transport of conservative solutes • m,, ,gen demand and re- aeratio n of flows • nitrogen dynamics. Conserva tive solute transport 1s being studied using slug mJect1ons of tritium to provide an indicatio n of evaporative losses . Sodium bromide · inj ection will be evaluated as an alternative tracer. Flow re- aeration will be studied using the propane desorption method (Kilpatrick et al. 1989). H igh concentrations of propane are inj ected into the stream and the flow sampled dow nstream. D esorption is proportional to the ra te of re- aeration. Nitrogen in leachate occurs mainly as ammo nia and orga ni c nitroge n (Petrozzi, 1994). Ammonium chloride is being inj ected to evaluate nitrogen attenuation rates. T emperature dependence will be assessed.

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In -s tream attenuatio n for landfill management and site selection is significant in managing po tential long-term contaminant discharges and incidental di sc harges cau sed by infras tru cture failure . The knowledge gained could be applied to the design of engineered channels with the aim of partial trea tment. Knowledge of the retention time etc would also improve the management of other waste spills by predic ting the rate of travel of a contaminant plume . WATER MAY/ JUN E 1997

53


In November 1996 Peter Gross spent three weeks in Shinjuku with Nihon Suido, one of the largest water supply and wastewater system consultants in j apan. The visit was part of an exchange program between the Association of Consulting Engineers Australia (ACEA) and the Association of Japa nese Consulting Engineers (AJ CE). Here reports briefly on some of the innovative features of the wastewater treatment systems in and around Tokyo. Tokyo is one of 47 regions, or 'prefectures', in Japan and has a population of approximately 11 .8 million in an area of approximately 2200 km2. Tokyo prefecture is surrounded by four other prefectures in the greater Tokyo area with a population of a further 33.5 million people. The prefec tural governments in Japan have the authority of planning, constructing and operating the sewer systems. Over the last five years Tokyo prefecture has spent approximately 54

WATER MAY/JUNE 1997

US$ l 65 billion to increase the proportion of sewered population from 44% in 1990 to 55% in 1995.

Sludge (Blosollds) Incineration. Approximately 80% of Tokyos production is incinerated, the majority in centralised facilities to which sludge is pumped by pressurised pipelines. One of the most recent plants is the Nanbu Sludge Treatment Plants built on reclaimed land in Tokyo Bay. Uses. The beneficial use of sludge is common. There are four main outputs: • lightweight aggregate, which is used as a building material and reformed into commercial products such as flower pots and park furniture • fuel from a successful application of multi-effect evaporation, or 'CG process,' at the Nanbu Sludge plant. Dewatered sludge and 1800 kW of energy were produced. T he major steps of the CG process are oil mixing, multi-

effect evaporation and oil water separation • melted slag used for a wide range of applications from road base to jewellery. Sludge is hea ted to approximately 1500° C, forming sludge melted slag. This slag has half the volume of sludge incinerator as h , thus saving in landfill volume, and is highly stable, with all metals being fixed • pressed burned bricks from pressed moulded sludge ash burned at approximately 1050° C used to manufacture interlocking bricks.

Wastewater Replenishing A ' Natural Resource Advanced wastewater treatment is operated at the Ta magawa Sewage Treatment Plant, located on the banks of the Tama river. T he process includes the use of ozonation followed by continuous backwash filtration.


WASTEWATER In about 1700 AD a waterway was constructed to take water from the Tama River to the centre of Tokyo. Later a water treatment plant was con stru cted and treated water was distributed to city inhabitants. The plant has long been closed, but the waterway remained as a natural resource until about ten years ago, when the waterway was diverted to a water treatment plant in the Tama area. The advanced treatment pl.int at Tamagawa was then con structed to provide advanced treated effluent downstream of the diversion to maintain the ecosystem of the stream.

Reuse for Tollet Flushlng As one of the main business districts of Tokyo, Shinjuku has the larges t co ncentratio n of highrise buildings. About ten years ago the Shinjuku Water R ecycling Centre began operation. It takes filtered sewage treatment plant efflu ent from the Ochiai Plant, provides supplementary chlorination and distributes the recycled water to 23 buildings in the area. The water is used primarily for toilet flushing.

.

STP A Community Resource Most sewage treatment plants in the inner city area are either constructed underground or have had covers constructed over the top of them. The area above the treatment plant is then used as a community resource for public recreation, e.g. baseball fields and open park space.

Use of Heat In Sewage In 1994 a facility to provide a heat source for the Koraku 1-chome area was established. The heat source is used for a regional air-conditioning system . A heat exchanger is used on degritted sewage, the heat going to a heat pump which supplies hot water to users.

son (Sewer Optic Fibre Teleway Network) Plan Fibre optic cables are currently being installed in the sewers of Tokyo principally to allow better transfer of information between pumping stations and treatment plants. However, the future may see a greater network of fibre optic cables installed in sewers for a broader use.

Author Peter Gross is a senior environmental engineer with Sinclair Knight Merz (PO Box 246, Spring Hill 4004, tel. (0 7) 3244 7100) and head of their treatment technology group in Queensland. WATER MAY/JUNE 1997

55


WASTEWATER Apology: This paper was printed in the

March/ April issue ofWater without the .figures and is reprinted in full here.

Summary Activated bio solids ansing from aerobic treatment processes are in some installations dewatered directly by belt press or centrifuge . The results in terms of dewatered cake solids from installations around Australia have shown a great deal of variabiliry. Comparing the dewatered cake solids against the percentage of non-volatile solids (ash) in the dewatered cake has established a strong correlation . This allows specifiers and suppliers of dewatering equipment to better characterise the biosolids, in order to form a basis for agreed performance of the equipment. A simple observation method is also proposed, which allows a quick evaluation of whether the dewatering device is close to the optimum performance on a particular biosolids mass. The data is based on conventional belt press performance, however it is also applicable to conventional centrifuges. A new generation of belt presses and centrifuges offers higher performance, but this is still within the expected performance band of the data.

Introduction Activated bio solids processes are currently in fashion around the world, and particularly in Australia, due to our relatively low energy cos ts. These processes include intermittently decanted aeration , continuous aeration, secondary activated biosolids processes, and biological nutrient removal. All of these processes result in excess biosolids. Some are thickened prior to anaerobic digestion but most are direc tly dewatered for disposal to landfill or for further processing, e.g. by incineration. A wide variation in the solids content of such biosolids cakes, ranging from 11 % solids to 20% solids, has been encountered at plants of similar process design, even using identical dewatering equipm ent, at different installations. The physical nature and appearance of the cake can also be the same for very different solids contents (Bane, 1990) . The variery of treatment processes in use today, as well as variable influents, can result in varying ash contents of the cake, and this value is often not stated or known at the pre-construction phase . This paper proposes the use of the nonvolatile (ash) solids content of the dewatered cake as an indicator of the attainable dewatered solids content of a particular biosolids population. The ash content of the filter cake, rather than that of the feed suspension to the dewatering plant, is used since dissolved solids in the liquid phase can provide variable values through the treatment process. It could 56

WATER MAY/ JUNE 1997

DEWATERABILITY OF

ACTIVATED BIOSOLIDS I H Bane enable a better estimate of the dewatering potential to be established.

Discussion Physical appearance. A factor w hich is often not realised by engineers working purely on a theoretical basis is that even though the solids contents of the filter cake might range through a wide set of values, the appearance and handling characteristics of a well dewatered biosolids cake are often virtually identical for a 11 % solids cake compared to an 18% solids cake. This is particularly so in the case of the belt press, where the shearing action and the compressive processes produce a cake which is easily handled and of a dry appearance. Slmple test. A simple but reliable test of the dewatering efficiency of a particular system can be made by observing the cake as it discharges from a belt press. If it is of a dry, crumbly appearance , and a sample when compressed in the hand only produces a few drops of moisture , then it is well dewatered. High solids contents. Anecdotal evidence suggests that in some countries , such as China, the attainable cake solids in an activated (aerobic) biosolids pro cess is in excess of 20% solids. However, this data has not yet been confirmed by the author. It is, however, believed that the high proportion of industrial wastes in the influent to the treatment works can raise the ash content of the cake and therefore the solids content. Also , some plants dosed with metal ions or lime can have a higher biosolids ash, and a few such plants exist in Australia, particularly in Sydney. Biological Nutrient R emoval plants also appear to produce higher cake solids.

Getting More Predictable Results In the past there have been instances w here dewatering equipment suppliers have been penalised due to the actual plant dewatered biosolids cake solids content falling below an arbitrarily fixed

design figure. A survey has been conducted and the results show that if the ash content is known prior to installation , the results will fall w ithin a narrower band and the performance of the equipment can be predicted more accurately. Table 1 shows a summary of the data from a number of individual plants. The majority of the results were with one manufacturer's range of belt presses . However, those from other manufacturers' equipment are included. The results are a combination of data taken from grab samples on operating plants w hich are not necessarily optimised, as well as data from acceptance tests , where the equipment has been optimised by skilled operators. The results expressed in graphical form show a good correlation between the non-volatile solids (ash) content and the attainable cake solids (see Figure 1) . The scatter in results can be attributed to the fact that some of the plants were not optimised (as described above) and variations in the selection of the equipment, as well as the design of the individual piece of equipment, and its design capacity. Most designs ofbiosolids dewatering equipment do not have an absolute maximum capacity, and the operating point for the equipment could be above or below the optimal capacity of the dewa tering device. However, the normal range of commercial loadings usually results in a variation of 1 or 2 percentage points in cake solids when the throughput is reduced, unless the dewatering plant is heavily overloaded. In general, the processes employed in the treatment plant do not appear to have a direct measurable effect on the attainable cake solids, except that w hen dosing with metals is pa~t of the treatment process this can result in a higher ash content of the cake . As discussed above, a high incidence of industrial influent can have a similar effect. Biological Nutrient R emoval processes appear to produce quite a good cake, as do some intermittent processes incorporating aerobic final digestion.


WASTEWATER Dewatering of anaerobically digested biosolids is a well established technology. Results from a number of plants in Europe are shown in Figure 2. When plotted on the same axes as Figure 1, they show a similar correlation between the cake solids and the ash content.

Polymer Dosage A secondary fac tor is that a cake with a higher ash content will require an apparently lower polymer dosage rate. T his is due to the non-volatile solids generally having a lower polymer demand, and w hen the rate is expressed as a dosage rate per tonne of dry solids, the numerical result is a lower figure.

New Generation Devices · The latest designs of high solids belt presses and centrifuges (Sernagiotto, 1996; Retter and Schilp , 1994) can achieve higher solids contents than those indicated by the regression line of Figure 1. The diaphragm type filter press can achieve similar results. These types of equipment are generally twice as expensive as conventional equipment, and would only be used in Australia in instances where the small difference in water removal is significant in terms of disposal costs. In Australia , where landfill and further treatment such as dosing with lime for stabilisation is currently used and land disposal costs are an order of magnitude less than those in Europe and the Americas, the small difference in water content has to date not justified the cost of the new generation of dewatering equipment.

Table 1 Survey of dewatering of aerobic biosolids Site

Supplier

Cake Solids% Ash Content % Notes

Boulder Bay, NSW Anglesea, Vic Toronto, NSW Gibson Island, QLD Wacol,QLD Loganholme, QLD Loganholme (New plant) Cairns South, QLD Cairns North, QLD St Marys, NSW Coombaba h, QLD Merrimac, QLD Merrimac BNR , QLD Rottnest, WA Edmonton , Qld Bateau Bay Port Macquarie, NSW

Terna Supaflo Supaflo Diemm e Supaflo Supaflo Supaflo Supaflo Supaflo Supaflo Terna Di emme YC Terna Supaflo Supaflo Alfa-Lava l*

11.35 13.8 15.86 12.5 13.7 18.3 15.7 14 13 16.85 10 13 15 11.87 14 11.7

15.54 29.8 33.84 10.5 10.35 40.6 33.3 19 25.5 29 .4 19 18 10 13.21 21 27 23.3

13.8

24.8

12

Average

No industria l or dosing No industria l or dosing No industria l or dosing Some industrial Some industrial Some industrial , 1987 Some industria l, 1995 Residential Residential Some ind ustri al, BNR Residential Residential Res identia l SBR Holiday Resort Residential Coastal-little industry

* Gravity table , then centrifuge

20

18 (/)

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• • ... •• • •

10

• Data from Sites

+ Regression

Line

8 10

20

30 40 PERCENT ASH ASH CONTENT (NON-VOL)

50

Figure 1 Effect of non-volatile solids on cake so lids after dewatering

Conclusion A correlation between ash content and dewa terability of activated biosolids from aerobic processes has been established , and can now be used as a benchmark for performance of dewatering equipment. The characterisa tion of the nature of the activated biosolids can therefore be enhanced by a nomination of the anticipated non-volatile solids of the dewatered cake. Treatment plants with a high proportion of industrial waste in the influent can produce a higher as h content biosolids cake, and hence a higher solids cake. In the past, process performance specifications for greenfield plants have not been a reasonable method of ensuring adequate equipment due to the unknown nature of the sludge . If the ash content and corresponding cake solids requirements can be specified, the plant owner can determine the level of dewatering that will be achieved, and will be able to choose between the standard or high performance equipment. If a higher solids content than the regression line of Figure 1 is desired, the new generation of dewatering equipment will be required, but the cost will be much greater.

40 35 30

l

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(1)

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~ -0 .:.:

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(.)

15

35

40

45

50

55

60

65

70

75

80

Volatile solids 1% on TSl

Figure 2 Effect of vo lati le solids concentration on anaerobic cake

References Bane I H (1990) 'Belt Press and Gravity Table D ewatering Process Performance-Myth and R eality'- AWWA Q ld R egional Conference Cabarita Lakes. R etter E A and Schilp R (1994) 'Solid Bowl Centrifuges for Wastewater Sludge Treat111ent'Filtration and Separation - June. Se rn~giotto (1996) Pilot Trials at C.O .R .D .A.R. (Italy) Comparison between

BPF WR New Generation Belt Press and N oxo n and Humbolt high performance Centrifoges. (Unpublished)

Author Ian Bane is Manager-Environmental Engineeringfor Supajlo Technologies Pty Ltd, 1/25 Frenchs Forest Road, Sydney WATER MAY/ JUNE 1997

57


WASTEWATER

Abstract Geelong has entered a new age of sewage treatment with the construction of the $43 million state-of-the- art secondary treatment plant at Black Rock. The plant, w hich is the largest of its kind in Australia, uses the intermittently decanted extende d aera tion activated sludge process. It was commissioned during 1996 and produces a high effluent quality w hich more than meets the Victorian Environment Protection Authority (EPA) requirements and the needs of the communi ty and will continu e to do so well into the next century.

Introduction In March 1990, the Geelong and District Water Board, now Barwon Water, commissio ned Co n sultants Gutteridge Haskins and Davey to carry out an independent review of sewage treatment and disposal in the Geelong region. The review, w hich included an extensive public consultation process, was completed in M ay 1991 and Barwon Water adopted a wastewater strategy in September 1991. One of the key elements of the strategy is for Barwon Water to establish a compact high-grade treatment facility at Black Rock on Bass Strait to treat Geelong's sewage to a standard which at least m eets the requi rem ents of the EPA, provides fo r environmentally safe disposal of the treated efflu ent to the marine environment and allows for future reuse applications . On 23 April 1991 the EPA issued an am ended licence for the discharge of wastewater

into Bass Strait from Black Rock. To meet the conditions of the new licence, Barwon Water needed to upgrade the existing facility to secondary treatment and to have the new works operational by 30 June 1995 . Licence requirements are shown in Table 1. Although not listed in the EPA licence, the concentrations of surfactants and oil and grease are of concern in the Geelong discharge, the surfactants because of the potential effect on coastal vegetation and the oil and grease because of their effect on surfers and bathers . Removal efficiencies of surfactants, oil and grease were therefore a consideration in the selection of the treatment process. There was no requirement to reduce phosphorus since the discharge is from a submarine outfall 1.2 km offshore. The treatment plant at Black Rock

currently serves about 174,000 people plus industries in Geelong and suburbs as well as the nearby tow nships of Lara, Leopold , D rysdale, C lifton Springs, Torquay, Barwon H eacls , Ocean Grove, Pt Lonsdale and Queenscliff. Barwon Water also has separate treatment facilities at Anglesea , Winchelsea and Portarlington. Before the IDEA plant was constructed sewage was screened at a screening plant. The screens in the plant had a 0.5 mm aperture and effectively removed most solids, grit and a significant amount of oil and grease. The sewage then passed through grit tanks before disposal to the ocean through a 1.2 km submarine outfall. The grit tanks were decommissioned but the screening and dispo sal processes were integrated into the plant's new process.

Table 1 Req ui red Pollutant Removal Efficiencies Waste Indicator, mg/L

BOD

ss

Ammonia nitrogen Organic nitrogen Tota l phosphorus Colour, units Tota l cadm ium Tota l chromium Total copper Total iron Total lead Tota l mercury Total nicke l Total zinc E. coli

Screened sewage concentration Median 370 360 39 24 8.6 125 0.005 0.15 0.17 2.6 0.05 0.0003 0 .04 0.26 ix 107

Maximum 490 480 57 51 10 200 0.016 0.34 -.27 4.8 0.24 0.0017 0.28 0.46

Average removal efficiency

Required effluent concentration Median 40 60 20 20 10 200 0.005 0.05 0.05 2 0.05 0.0005 0.05 0.1 5x 104

Maximum 80 120 25 40 15 300 0.01 0.1 0.1 4 0.1 0.001 0.1 0.2

I

% 89 83 40 17 Nil Ni l Ni l 67 71 23 Ni l Ni l Nil 62 99.5

WATER MAY/ JU NE 1997

59


WASTEWATER Project Funding The Black Rock Sewage Treatment Plant upgrade was one of a number of projects identified in the was tewater strategy. T his project and an STP upgrade at Anglesea required signifi cant fundi ng. In 1991 Barwon Water introduced a Special Environment Protection Levy on customers which ran for five years to fund these and other wastewater strategy projects. The levy has given an overall benefit to the community, which now has a plant that uses proven natural processes and world's best technology without being saddled with a huge debt which wo uld need funding well into the fut ure.

. Selectlon of the Treatment Process Following a review of a broad range of treatment options the following processes were reviewed and trialled: co nventional activated sludge, nitrifying activated sludge, conventional extended aeration activated sludge, intermittently decanted extended aera tion activated sludge, trickling filter- solids contact , Memtec microfiltration and Sirofloc . A pilot plant to trial the first five processes was built at the Black Rock site using a package treatment plant obtained from M elbourne W ater. A 30 L/min (30M10) microfiltration plant was purchased from Memtec for the microfiltration trials and the CS IRO completed bench scale tests for the Sirofloc process. Details of these trials have been provid ed previously by Sewards and Williams (1993 and 1995). T he IDEA system was selected for the Black Rock upgrade based on consideration of a number of factors. The determining factor was the sideby-side operation of the five processes trialled in the pilot facility. The M emtec and Sirofloc processes had been discarded after bench trials becau se they could not meet the disc harge requirements on their own . With the excep tion of ammonia nitrogen in the conventional ac tivated sludge process, all remaining systems met the EPA licence criteria , but the IDEA system appeared to do so with the least complications and required only routine operator attention. The IDEA process was preferred based on a comparison of pollutant removal efficiency, ability to meet EPA req uirements, ability to cope with shock organic and hydraulic loadings, reliability, flexibility and robustness, routine opera tor intervention requirements, potential for odo ur productio n and capital and operating costs. Although it was recognised that the IDEA system was energy-intensive, it was considered that the o ther advantages 60

WATER MAY/ JUNE 1997

constraints of the head available from the screening plant and the head required to drive the outfall . The final design provided 200 mm 'spare' head in the worst case scenario. Discharge from the IDEA plant is always at maximum (210ML/day) rate . Only the duration of discharge varies. Materials. The harsh coastal conditions provide a corrosive environment. Incoming sewage is somewhat septic. Rock. The extensive area of rock onsite impacted greatly-o n the depth of the tanks.

of the system , including overall lower operating costs, outweighed the energy disadvantages.

Plant Design Detailed design for the proj ect was completed using a mix of in-house and external consultant services. Coordination of design elements was by Barwon Water, process design by Envirocon Consulting Engineering and structural and architectural design by Gutteridge Haskins and D avey. The key design parameters were: Average dry weather flow 70ML/day Peak weather flow 210ML/day Average BOD 370mg/L 360mg/L Average suspended solids F/M ratio 0.05kg BOD/kgMLSS .d 36 hours D etention time MLSS 5,000 mg/L 30 days Sludge age

Resulting Design As a result of the hydraulic and rock constraints the tanks were constructed partially below and partially above natural surface level. Excavated material was placed as a batter to the tanks to minimise their visual impact.

Process Design Constraints

Figure 1 shows a pro cess flow diagram fo r the plant. After screening, raw sewage and return activated sludge (RAS) (at up to 50% of ADWF) are mixed at the head of two selector tanks w hich operate in parallel. Flow through the selectors is plug flow with an average

There were a number of constraints on the design of the plant. Hydraulic considerations. No additional pumping was to be incorporated in the system , so hydra ulics had to be carefully designed w ithin the

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WASTEWATER detention time of one hour. Sewage in the selec tors is continuou sly aerated becau se nutrient removal is not a requirem ent. However, the selectors can be converted to include anaerobic and anoxic zones in future if necessary. The main purpose of the selec tors is to enhance the development of desirable micro-organisms and to discourage the development of undesirable organ.isms such as filamentous bacteria which can lead to sludge bulking and foaming problems. Flow from the selectors is evenly distributed to four large (120 m x 60 m x 3.5 m deep) IDEA tanks. T he IDEA tanks are supplied with diffused air from a central aeration facility located next to the tanks. The process is_operated in four distinct phases over a four- hour cycle with each tank operating in sequence to enable maximum energy savings. Feed to all four tanks is continuous and is through a diffu ser in the centre of each tank. The operation phases are : Phase 1 - aeration - duration 2 hours all liquid and sol.ids fully mixed Phase 2 - settling (no aeration) minimum duration 1 hour Phase 3 - decant - from both ends, up to 50 minutes

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Phase 4 - idle - up to 10 minutes to allow decanters to raise above liquor level. Sludge can be wasted from each of the fo ur tanks by gravity feed. Currently WAS occurs during the aeration phase to maintain a constant sol.ids content (0. 5 %) to the sludge handling facilities. D ecant from the IDEA tanks is achieved using eight skimmers in each tank. The skimmers were designed by Transenviro (USA) and were supplied by Environmental Solu tions International. A baille arrangement on the skimmer allows supernatant to be drawn from just below the surface , ensuring

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that the best quality supernatant is decanted at all times. A channel aro und the tanks conveys the decanted eilluent to the ocean outfall pipeline. T he channel also acts as a storage for reuse water applications including on-site irrigation. The M emtec plant purchased for pilot trials has been incorporated into this reuse system .

Aeration Tank Design

D esign of the aeration tank s was completed by Gutteridge Haskin s and Davey and has incorporated a number of special features. Construction base level of the tanks was at RL2.4 m , where the foundation was partially on solid rock and partially on expansive clays. To overcome foundation difficulties areas of clay were excava ted to below static groundwater level and replace d with compac ted crushed rock. Consideration was given to the use of prestressed concrete elements but investigations indica ted that, except for walkway elements , prestressed elements offered no advantage. D esign was completed on the basis of reinforced concrete, although construction contractors offered an alter1:a tive design. The floor of the tanks is independent from the walls and is only 130 thick. H ydrostatic pressures are co ntrolled by an extensive underdrain system w hich also enables Barwon Water to monitor any leakage from the tanks. Because of the harsh coastal environment conditions at Black Rock, careful consideration was given to the concrete mix design. 50 Mpa concrete with a minimum 5% silica fume was specifi ed and the addition of flyash or blast furnace slag was recommended_

Aeration System Design D esign of the aeration system was completed by the subcontrac tor, Aquatec M axcon. T he design included the following key features _ T he system incorporates three large (40,000 m3/hr) blowers for the IDEA tanks and two booster blowers for the selector tanks. The blowers, w hich have outlet diffu ser vanes and inlet guide vanes to optimise efficiency, are housed in acoustic enclosures. Aerators are the fine-bubble 'ElastoxT' disc-type membrane diffusers from GVA mbH ofWest Germany. The diffusers are mounted on special diffuser assemblies which can,be isolated and removed by a travelling gantry crane without having to shut down the IDEA tank.

Thickening and Dewatering Sludge thickening and dewatering is achieved using a combination of gravity WATER MAY/ JUNE 1997

61


WASTEWATER decks and belt presses. The contract for this elem ent of the proj ect allowed tenderers to submit proposals for all methods of thickening and dewatering. Proposals were received for dissolved air flotation (DAF), gravity decks , centrifuges and belt presses. W arman International submitted the successful bid which consisted , of four trains of gravity deck plus belt press. The system receives WAS from the IDEA tanks via a small aerated holding storage at 0.5 % solids. After flo cculation using a polyelectrolyte, free water is removed by the gravity deck and returned to the screening plant. Solids content is about 3% prior to the belt press. The belt press increases solids content to about 16%. Screw conveyors co nvey the sludge to tru cks which dispose of the sludge to long-term, onsite storages.

Plant Control The plant is fully automated using a Symax Square D PLC control system w ith PC interface. The operator controls the plant using the Australian developed software, 'Citect', which also allows remote operation by the operator by laptop computer and provides data logging. Because of the Citect system and backup telem etry and telephone alarm systems, the plant is only staffed during normal working hou rs, with operator callouts as necessary.

Construction The contract for the construction of the treatment plant was awarded to Fletcher Construction Australia and was scheduled for completion on 30 June 1995. A number of subcontracts were awarded before the main contract to enable detailed design to proceed and were as follows: • Aquatec M axcon-Aeration System International-Sludge • Warman Dewatering • Siemens-Electrical • Hunter Water CorporationInstrumentation and Control. The Superintendent for the works was Gutteridge H askins and Davey. Works comm enced on-site in April 1994. Practical completion was achieved on 23 August 1996.

Plant Performance Commissioning of the plant involved the introduction of sewage only. No imported sludge or mixed liquor was used from any other treatment facility. The biomass was generated by its own self-seeding. This process was trialled in the pilot plant and proved successful, with the biomass stabilising in six to eight weeks. Figure 2 shows the development of the biomass during this period. With respec t to BOD and suspended solids, a stable biomass was 62

WATER MAY/JUNE 1997

achieved within eight weeks (see Figure 3). Since the completion of its commissio ning the plant has con sistently achieved the following results: BOD <10 mg/L (see Figure 4) SS <10 mg/L (see Figure 5) Ammonia Nitrogen < 0.5 mg/L Organic Nitrogen <5 mg/L It should b e noted that nutrient removal is not a requirement for the plant.

Conclusion

sewerage sys tem well into the next century without saddling the community with additional debt. The IDEA plant has provided a cost-effective solution to one of the world's biggest problem s-sewage trea tment and disposal.

Acknowledgements The author wishes to acknowledge the assistance given in the preparation of the paper by Dr Gordon Sewards (E nvirocon Consu.lting Engineering) and N eville Pearce (Barwon Water).

Overall, the performance of the plant has exceeded expectations. E fflu ent References quality is well within EPA licen ce Sewards, G J and Williams, G C H (1995) Intermittently Decanted Extended requirements and the plant has been easy Aeration Process, Modern Techniques in to operate with minimal operator interWater and Wastewater Treatment, ference. Most pleasing has been E. coli CSIRO, East Melbourne, Victoria. levels in the ocean. With the ocean Sewards, G J and Williams, G C H (1993) outfall pipeline receiving screened Black Rock Sewage Treatment Plant Upgrade Pilot Plant Trials, Proceedings sewage, Barwon Water often had diffiof Australian Water and Wastewater culty in achieving EPA licence requireAssociation 15th Federal Convention, ments for E. coli on beaches and was Queensland . frequently cri ticised by the local media and surfers. The introduction of the Author IDEA plant has resulted in the levels of Gwyn Wllllams is a civil engineer who E. coli dropping to single-figure graduated from Monash Un iversity. H e background levels, en suring a safe worked fo r the G&DWB in project manageenvironment for all. Completion of the plant ensures that ment for twenty years and is n.ow Ma nager, Barwon Water will continue responsible Asset Development, Barwon Region Water environmental management of its Authority.

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Water Journal May - June 1997  

Water Journal May - June 1997