Water Journal January - February 1997

Volume 24 No 1 January/February 1997 Journal of the Australian Water & Wastewater Association

CONTENTS

Editorial Board FR Bishop, Chairman B N Anderson, G Cawston, M R Chapman P Draaycrs, W J Dulfcr, G A Holder M Muntisov, P Nadcbaum,J D Parker

ASSOCIATION

NEWS

From the Federal President ................................................. inside front cover From the Executive Director ...............................................................................2

AJ Pricstlcy,J R..issman

Advertising & Administration

MY

POINT

OF VIEW

AWW A Federal Office Editorial: Helen Cumming

Advertising: Sandra Brennan PO Box 388 Artarmon NSW 2064

A World Class Industry ........................................................................................ 3

John Olsen

Level 2, 44 Hampden Road, Artannon

WATER

Tel (02) 9413 1288 Fax (02) 9413 1047

Email: awwa@abol.net

Features Editor

Prospect Water Filtration Plant ......................................................................... 7

EA (Bob) Swinton 4 Pleasant View Crcs, Glen Waverly Vic 3150

Detecting Protozoa in Water: A Comparison of Methods ............................ 9

Tel/Fax (03) 9560 4752

Branch Correspondents ACT - Ian Bergman Tel (06) 248 3133 Fax (06) 248 3806

New South Wales - Mitchell Lagincstra Tel (02) 9412 9974 Fax (02) 9412 9876

G Henderson B Faulkner, R Thurman, D Veal, A Champion Contamination of Samples for DOC Analysis ............................................... 12

J van Leeuwen, M Drikas, D Bursill, B Nicholson Aquifer Storage and Recovery ......................................................................... 13

T Pillar

Northern Territory - Ken McFarlanc Tel (08) 8924 7606 Fax (08) 8924 7161

Quceusland - Terry Loos T cl (07) 3224 2146 Fax (07) 3369 4816 South Australia - Peter Martin Tel (08) 8303 8723 Fax (08) 8303 8750

Tasmania - Dao Norath Tel (03) 6233 2596 Fax (03) 6234 7559

ENVIRONMENT Catchment Management Within Agencies: Where Bottom Up Meets Top Down .......................................................................................................................15

J Howard

Control of Cyanobacterial Blooms in Weir Pools .........................................18

Victoria - Mike Muntisov

IT Webster, G J Jones, R L Oliver, M Bornuns, BS Sherman

Tel (03) 9600 1100 Fax (03) 9600 1300

Sampling and Analysis of Water-Meeting the Objectives of the Australian Water Quality Guidelines ................................................................................... 21

Western Australia - Jane Oliver Tel (09) 420 2462 Fax (09) 420 3178

Water (ISSN 0310 • 0367)

W Maher, C leGras, A Wade

is published six times per year: January, March, May,July, September, November

by

Australian Water & Wastewater Inc ARBN 054 253 066

Federal President

WASTEWATER PETWIN™-a Modelling Tool for the Petroleum Industry ............................ 25

AJ Baker

Recycling of Reclaimed Water in South Australia ...................................... 30

NM Kayaalp

Mark Pascoe

BUSINESS

Executive Director Chris Davis 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 classified advertisements arc included as an informational service to readers and arc n:vicwed by the Editor before publication to ensure their relevance to the water environment and to the objectives of the Association. All material in VVatcr is copyright and should not be reproduced wholly or in part without the written permission of the Editor.

Subscriptions IVater is sent to all members of AWW A as one of the privileges of membership. Nonmembers can obtain Water on subscription at an annual subscription rate of S35 (surface mail).

Liability of Authorities and Their Consultants ............................................. 36

N Hemmings Australian-Indonesian Activities in Water and the Environment ............ 39

I Bergman DEPARTMENTS International Affiliates ....................................................................................... 4 National Affiliates ................................................................................................ 6 From the Bottom of the Well ................................................. inside front cover Meetings .................................................................................... inside back cover Our Cover The Prospect Water Filtration Plant was officially opened by the NSW Premier, Bob Carr, on 4 November 1996 after a successful commissioning trial (see page 7). Like the other contracts let by Sydney Water Corporation as part of the Drinking Water Quality Program, it is a build-own-operate project. It will treat up to 3600 ML/d, making it one of the largest treatment plants in the world. The plant is owned by Australian Water Services.

FROM

THE

EXECUTIVE

Dumping People Can Leave a Utility Vulnerable

Is Reform on Target?

Fads Rule, OK? Management fads sweep the world on an ongoing basis, as a new way of labelling and packaging a commonsense approach to managing is promoted, distorted and then ultimately overtaken by a still newer fad. The water industry is as prone as all others to this and, through the network, adopts fads quite coherently-so they are all too easy to spot.

Economic rationalism or, as some call it, managerialism, is the cu rrent fad.

The bottom line is all that matters, as long as agencies keep on the right side of regulators. This is in strange contrast to the real world of business where staff are now acknowledged as a primary resource and w here acting as a good corporate citizen is accepted as vital.

Governments Set the Tone One cannot blame water utilities entirely for this lack of breadth in their vision-they are, despite the co rporatised statu s of many by now, still handmaide ns of governmen t and gove rnments set the tone for their performance. While some state governments have inherited awful debts from their predecessors, necessitating cost cuts and drastic reform, there is still a prevailing emphasis on financial performance and staff reductions.

Paradoxically, the same governments which impose stringent financial goals are, in a couple of instances, demanding great things in the area of recycling of effluent, probably because of th e

New Members ACT Peter Burnett, Ronald Hogg, Robert Thompson New South Wales John Alexander, Robert Angel, Thomas Baldwin, David Byrne, Garth Callaghan, Timothy Carroll, Paul Catt, Yee Chee, David Cook, Lisa Corbyn, Claudia Cowell, Emma Craig, Keith Disher, Annalisa Dixon, Jack Domls, Darron Ellery, Gregory Empson, Melanie Gowlland, Jing Guan (Student), Douglas Hurst, Darrell lies, Stephen King, Terry Knowles, Patty Kolin, Ian Law, Peter Linkson, Azhar Nomani, Mark Norris, Van Osgood (Student), Mangalam Raju, Mark Ramage, Adrian Ridgley, Frank Robinson, Ranaj it Samanta, Malcolm Sherlock, Stephen Short, Kevin Smith, Dianne Thomas, Gregory Watkins, Marianne Weaver, G Wilson, Jenny WIiiiams, Hong Yang, Qamar Zaidi Northern Territory Garry Coleman, Guan-Hua Gao, Noel McCarthy Queensland Diane Ames, David Angell, Robyn Barnard (Student), Belinda Bell, Ian Bradford, Rachael

2

WATER JANUARY/ FEBRUARY 1997

DIRECTOR

commonly held belief that recycling is always better than discharging used water back into the water environment. While recycling is and will contin ue to be an excellent option for some circumstances, it is definitely not a panacea, so blind insistence on maximum rates of recycling will impose costs, both economic and environmental.

Integration Holds the Key The healthy direction for water agencies is an integrated approach to doing business in harmony with their customers, stakeholders, owners and regulators. While the primary aim is to generate a re turn for owners by operating a water business, the corporations should have a self-imposed set of standards for corporate conduct, including social and environmental components, as well as a healthy relationship with staff Cutting costs by acting only on tho se aspects of behaviou r which will be pu rsued by regulators is short sighted. In many cases, regulators cannot match the resources of water utilities, so are unable to impose regulations adequately, leaving governments or the community to step in. This can lead to a loss of trust and a need for more fo rmal regulation, w hich is not necessarily the most effective model. Enlightened self-interest on the part of the utility should suggest that exemplary behaviour in all respects will keep stakeholders, customers and owners happy and thus threats of imposed change at bay.

Catlin (Student), Mark Coulson (Student), John Davies, Diana Dawson, Trevor Dowden, Kent Elssmann, Susan Emmett (Student), Paul Glennon , Margaret Greenway, Ian Hamilton, Brian Hawthorne, Peter Ireland, Danette Johnson (Student), Michael Lewis, Paul Marshall, Sydney McDonald, Daniel Ogg, Daniel O'Su llivan (Student), Daryl Polzin, WIiiem Ponsen, Jane Pott, Adam Sadler (Student), Malcolm Sherren, John Smith, Thomas Vanderbyl, John Ward South Australla MIiton Banfield (Student), Christopher Chow, Tim O'Connor, Kaye Spar k, Mark Thyer (Student), Tracy Venus (Student) Tasmania David Dettrick (Student), Cl Int Johnstone, Anne Leonard, Catherine Reid, Sama ntha Watkins Victoria Gary Baird, Dean Boyd, Colin Campbell, Dennis Carty, Dennis Denouden, WIiiiam De Vos, Christopher Fairley, Sara Fitzroy-Moore, Gail Hamilton, Simon Jaskl, Stephen Jenkins, Gregory Johnson, George Khouri, Kwan Lam, Erik Ugtermoet, Seker Mariyaplllai, Gary McConnell,

C utting staff levels brutally may indeed benefit the short term bottom line, but it leaves utilities vulnerable when institutional me mory is lost and vital skills are no longer held in house.

Contracting out of services can fill the vo id in some respects, but ca nnot compensate for a core of knowledge and skill relating to the critical performance areas of water services. When contracts are let to experienced companies with conside rable resourc es of their own, they can indeed add value to the operation, but the low cost operator may not b ring that added value and could make the utility vulnerable down the track.

Is Corporatlsatlon Just a Halfway House?

The industry grapevine suggests that corporatisation is, empirically, only an interim stage on the rou te towards full privatisation. It suggests further that the level of government intervention in corporatised agencies is so frustrating that most of the corporations would prefer to be fully privatised and to get on wi th their business unfettered.

We Should Debate These Issues All these ideas are c hallenging and could do with some wider discussion, a feature notably absent in Australia so far. While we will have some excellent presentations at the Federal Convention in Melbourne in March, there is every reason to flag th e issues, analyse performances and directions and to debate our future vigorously o n an ongoing basis. The mystical status of water in the community psyche is always going to make rational debate difficult, but we should acknowledge that emotional layer bu t still aim to have everyone involved better informed.

Chris Davis Colleen McKee, Daniel McLean (Student), David McMaster, Vict or Menpes, John Nolan, Neville Pearce, David Power, Neil Ryan, Tony Sheedy, Alexander Simopoulos, Carol ine Smith Western Australla Anthony Broom, Laurence Brodie-Hall, Murray Dixon, Johannes Drlelsma, Jane Oliver, Darryl Whiteley, Man Zhuang Sustaining Members Aeration Treatment Systems (Qld), Austeck pty Limited (NSW), Burkert Fluid Control Systems (NSW), Chemdrex Chemicals (NSW), Citechnologies Pty Ltd (NSW), Conlab pty Ltd (Vic), Du ra-WIiis Division of Euratech (Vic), Enretech Australasia pty Ltd (NSW), Haycarb Holdings Australia pty Ltd (Vic), Henry Walker Environmental (SA), Henry Walker Envi ronmental (WA), National Analytical Laboratories (Vic), Philmac pty Ltd (SA), PICA Activated Carbon Australia (Vic), Pumpability pty Ltd (NSW), Qld Health Scientific Services (Qld), Reliance Manufacturing Company (NSW), Sterling Pump Group (Vic), Streamline Australia (Vic), Unlsearch Ltd- Water Research Div (NSW), University of New England (NSW), Wickha m Gensol Australia Pty Ltd (NSW)

WATER

Background In 1990 Sydney Water decided to move forward with the private sector to improve the quali ty of the drinking water for the people of Sydney.

Traditionally, Sydney's water supply has bee n treated through catchme nt and storage management policies and disinfection , using chlo rin e and chloramines. H owever, the combination of urban growth in catchment areas and spasmodic heavy rainfall, exacerbated by limited options to manage incidents of high turbidi ty following heavy storms, led to a decision to move towards the more effective option of a physical barrier system such as filtration.

Australian W ater Services (AWS), a private Austra lian company, was formed to build , own, opera te and manage water systems in partnership with public authorities in Australia and N ew Zealand. AWS provides se rvices covering the entire water cycle, from drinking water fil tration to wastewater treatment.

AWS is jointly owned by Lend Lease Corporation Australia's leading property an d financial services company, and Lyonnaise des Eaux, the giant French environme ntal services conglome ra te and world leader in water treatment technology and water system s management.

From a very comp etitive international field of 17 conso rtia, the A WS

managed Prospect W ater Partnership, consisting of Lend Lease Corporation, Lyonnaise des Eaux and P&O Australia, was awa rded the co n tract. The contract, a Build , Own and Operate (BOO) for 25 years, has set the benchmark for future Australia water in frastructure projects.

The Prospect Plant The Prospect Plant provides filtered drinking water to over 80 percent of Sydney, more than 3 million p eople. It is one of the world's largest singularly-developed water filtration plants and can filter up to 3 billion litres of water per day.

The Prospect Plant is one of the most advanced filtration plants in the world. T he plant includes several technical innovations. The plant has a capacity of 3,000 Mid (4,200 Mid ultimate) high rate (24111/ h) direct filtration, including chemical addition and coagulation, deep b ed/large sand media filtration, disinfection with chlorine and ammonia, fluoridation, pH adjustment and residuals treatment.

The main fil tration process carried out at the plant is known as contact filtration . Chemicals are added to the water at varying stages in the process to coagulate the sediments. The steps involved include: • depen ding on t he quality of the untreated water, manganese ions are

oxidised to an insoluble form by addition of potassium permanganate and lime slurry to raise the pH to 8.5-9.0 • the pH level is adjusted using either sulphuric acid or lime slurry to en su re an optimum pH for coagulati on processes • depe nding on the quality of the untreated water , chlorine is added to bleach 'colouring matter' in the water and reduce the consumption of coagulation chemicals • the primary coagulant, ferric salt, is added to coagulate suspended solids and remaining coloured material in the water • a second coagulant, such as a cationic p olymer, is added at the same time as the water is pH adjusted to approximately 8 with lime water, to fu rther coagu late suspended solids in the water • a filter aid is used to strengthen the floe structure formed by the previous processes.

The water and sediments are then filtered th rough advanced technology sand filters to remove the coagulated solids from the water. The sand filters have been developed by a subsidiary of Lyonnaise des Eaux, D egremont and are named Aquazur V filters. They use a single, deep bed ofhomogeneous sand to produce more filtered water than standard sand fil ters. T he 24 filters at the plant are the largest ever built, with a filtering area of 237.9 111 2 per filter.

WATER JANUARY/ FEBRUARY 1997

7

Each filter has a sand bed depth of2.1 m filled with sand between 1.7 and 1.9 mm in diameter. The water depth above the sand bed during filtration is 2 m.

These specifications enable the filters to produce more than 24 m/h.

Backwashing of the sand filters occurs as they become clogged with solid material to restore their performance to optimum levels. The removed solids then have all water removed by centrifugal force. The solid matter is disposed of in a landfill, or put to beneficial use in an industrial capacity.

After filtration, the water is again pH adjusted with lime water. The treated water is stored in covered tanks, providing a buffer capacity for changes in demand from the distribution system.

Sydney's water supply is then disinfected by adding chlorine and ammonia at a chloramination plant just downstream of the filtration plant.

Operations contract targets for treated water turbidity levels arc 0.3 NTU or less, with a required rolling average of0.5 NTU or less. Operations since successful completion of the Operating Trial on 12 September 1996 indicate that the plant will exceed the drinking water quality contract requirements.

Operating Trial In accordance with the Water Filtration Agreement with Sydney Water the partnership was required to carry out an Operating Trial for a period of 30 days. The performance of the Prospect Water Filtration Plant was tested against the commissioning criteria which defined the key quality parameters to be achieved.

The Operating Trial was carried out between 13 August 1996 and 12 September 1996. During this period the Plant was tested on the various raw water sources and under maximum filtration rate. During the first 11 days, the Plant operated under normal operating conditions with the raw water being received from Lake Burragarong, supplemented by approximately 300 ML/day from the Upper Nepean Storages. The raw water received was of a high quality with an average Turbidity of0.6 NTU and Colour of 11 HU. The second part of the Trial incorporated for one week the operation of the Raw Water Pumping Station, supplying raw water from Prospect Reservoir in addition to the raw water received from Lake Burragarong. Also during that period, half of the plant was shut down in order to operate the available filters at their design rate and beyond.

The Plant was tested on raw water from the Upper Nepean Storages as a primary source during the third part of the trial. This also coincided with the 8

WATER JANUARY/FEBRUARY 1997

major storms that occurred in Sydney on the weekend of 31 August 1996.

The Upper Canal which transports raw water from the Upper Nepean Storages saw water quality deteriorate rapidly.

Turbidity of up to 26 NTU and Colour of 15 HU were being treated at the Plant before it was decided with Sydney Water to divert the Upper Canal water to Prospect Reservoir. At this time, the Turbidity in the Upper Canal reached 70 NTU. The plant performed extremely well under these quite adverse conditions.

During the first two days of the last week of the Trial, 50% of the plant was closed again in order to test design filtration rate with Upper Canal Water.

Sydney Water configured the distribution system so that maximum water could be drawn for this period. The commissioning criteria were satisfied on each day of the first 25 days of the Operating Trial.

The last five days of the Trial had to be completed without a failure in order to satisfy the requirements of the Water Filtration Agreement. This was easily achieved resulting in a fully successful operating trial being completed at 8.00 am on 12 September 1996. By achieving this outstanding result of completing the operation trial under very adverse conditions and difficult operating protocol without a single failed day, the Prospect Plant has set up the benchmark of world excellence.

Conclusion In all aspects, the Prospect Water Filtration Plant has been an outstanding success. Sydney Water had the foresight to take advantage of the competitiveness of the international market and the transfer of technology, and to seek the interest of the private sector in the development of this huge project.

Through its unique pedigree, AWS has accessed the design capabilities of the Prospect Water Group (the consortium between CMPS&F and Sinclair Knight Merz), the proven technologies of Lyonnaisc des Eaux and the project management and construction expertise of Civil and Civic, supported by many Australian contractors and suppliers.

The result has been a highly cost-effective plant, completed six months ahead of schedule, costing significantly less than first envisaged. It was officially opened on 4 November, 1996 by the NSW Premier, Bob Carr.

Author Greg Henderson is Projects 1vfa11ager for Australian Water Services, responsible for all their i1ifmstmcture development. He is a civil engineer who graduated from the University of New South Wales.

Concept Design First proposals for a treatment plant at Prospect were developed in the early 1960s. After extensive investigations, designs were prepared for a direct filtration plant.

In 1976, the project was deferred but was resurrected in 1989-90 as part of Sydney Water's Drinking Water Quality Program.

The Prospect Water Group, a joint venture of CMPS&F and Sinclair Knight Merz, working in association with Camp Dresser & McKee and Montgomery Watson, was appointed by Sydney Water to develop a concept design for a 3600 ML/d plant. An extensive program of testing was carried out in a pilot and prototype plant constructed on the site. Direct and contact filtration processes were investigated in detail. (AWW A 15th convention 1993, pp 188, 1113).

Combining polymer coagulants with alum demonstrated that deep bed, high rate filtration processes were viable. Pre-oxidation allowed the use of higher filtration rates.

Both pre-ozonation with filtration at a design rate of 35 m/h and prechlorination with filtration at 25 m/h were demonstrated to be viable processes for the wide range of raw waters to be expected.

The concept design report, completed in February 1992, recommended pre-chlorination, coagulation using alum with a cationic polymer, followed by deep bed filtration at 25 m/h. Provision was made for augmentation to 4200 ML/d, together with provision for ozone or other pretreatment at some later stage.

In 1991, Sydney Water called for expressions of interest from the private sector for a build-ownoperate plant and tenders were called from pre-qualified consortia in 1992. The concept design report was used as one of the benchmarks against which tenders were assessed.

Australian Water Services, with the Prospect Water Group as their principal designer, was awarded the contract in 1993.

In September 1994 Sydney Water decided, in view of the publicity concerning the possible role of alum in Alzheimer's Disease, to substitute iron salts for alum.

Sydney Water instructed AWS to carry out further pilot plant tests.

Following these, the plant was converted and successfully commissioned using ferric salts.

WATER

DETECTING PROTOZOA IN WATER: A COMPARISON OF METHODS B Faulkner, R Thurman, A Champion, D Veal Abstract Ostensibly 'safe' drinking water infected 400 000 people in Milwaukee with cryptosporidiosis in 1993.

Conventional water microbiology cannot cope with the detection of parasites whose presence is often not linked to traditional indicators of faecal contamination. However, methods of testing arc constantly evolving. This paper compares two methods for detecting protozoan parasites in water, appropriate for both sophisticated urban laboratories or rural laboratories servicing small populations.

Introduction The protozoan parasites Cryptosporidiu111 and Giardia arc of particular concern to water utilities throughout the world. Their concern stems from: • the wide range of animal hosts that Cryptosporidiu111 and Giardia may infect (Barer & Wright, 1990; O'Donoghue, 1995) • the low infectious dose of these organisms (Miller el al, 1990; Blewett et al, 1993; DuPont et al, 1995) • the environmentally robust nature of Cryptosporidi11111 oocysts and possibly Giardia cysts, which may survive in the environment for months (O'Donoghue, 1995) • the resistance of these Giardia cysts and Cryptosporidi11111 oocysts to most commonly employed methods to disinfect water (Korich et al, 1990) • the lack of correlation between the presence of Giardia cysts and Cryptosporidit1111 oocysts and indicator organisms (Rose et al, 1988; LeChevallier el al, 1991a; Ashbolt and Veal, 1994).

Several large waterborne outbreaks of cryptosporidiosis have occurred in the US and UK (D'Antonio et al, 1985; Hayes et al, 1989; Poulton et al, 1991).

The most dramatic waterborne outbreak of cryptosporidiosis to date occurred in Milwaukee in 1993 where approximately 85 people associated with the outbreak died (Pontius et al., 1993). Giardia has long been recognised as a cause of waterborne gastrointestinal disease (Boreham et al., 1989).

Cryptosporidi1m1 and Giardia cannot be routinely cultured and detection therefore relies upon the direct exami-

Methods

Sampling sites. Devils Creek nation of water samples. The low infec- (Moorabool Catchment, 853 hectares) tive dose of these parasites (Blewett et and Giles Creek (Yarrowee River al, 1993, DuPont el al, 1995) requires Catchment, 761 hectares) are situated large volumes of water (at least 1 to 100 approximately 20 kilometres north-east litres) to be analysed to ensure an of Ballarat in Victoria, Australia. Both acceptably low level of risk. This is in range from grassed rolling hills to flat contrast to the small volumes analysed farmland that is boggy and swampy in for indicator organisms that are present areas. The area is predominantly rural in much greater numbers. The actual with cattle grazing and potato producvolume analysed depends on the sensi- tion the main land uses. Stock have tivity required and the recovery rate of limited access to the creek and run-off the method employed. Several different from pastures flows directly into the methods for concentrating large volumes creeks. Possible sources of faecal then purifying and analysing water contamination include cattle, native animals and septic tank seepage. The concentrates have been developed.

For the concentration of water annual rainfall is between 800 to 900 samples the three main methods that 111111.

Blue Eye Creek is surrounded by a arc routinely employed arc cartridge filtration (APHA, 1989), membrane pristine hardwood forest which is flat filtration (Hansen and Ongerth, 1991) and ~wampy and contains mixed native species. and flocculation (Vesey et al, 1993a).

This land is currently managed by After concentration, water samples arc normally stained with fluoresccntly- the local water authority as a water labcllcd monoclonal antibodies, specific catchment area with no native forest to Giardia cysts or Cryptosporidi11111 harvesting. Native animals arc a possioocysts. The concentrated water ble source of faecal contamination.

The West Moorabool River at samples are then examined using fluorescence microscopy. The typical O'Conner's Road has pasture land with pellet volumes, after concentration, are sheep and cattle on one side and a generally too large (up to 5 mL) to be pristine eucalypt forest on the other effectively examined by microscopy bank.

Sample collection and preparation. and a further 'purification' step is normally employed. The two maJor Twenty litre samples of water were collected from Giles Creek, Devils approaches to purification are: Creek, Blue Eye Creek or the West • density flotation, in which dense particles sink whilst the cysts and Moorabool River in plastic carboys and oocysts are retained on a density transported to Australian Catholic University laboratory for flocculation cushion • flow cytometry that sorts particles on and processing.

Samples were flocculated by the the basis of their size surface texture and method of Vesey et al (1993a). The floes fluorescent properties (Fricker, 1995).

Surveys of surface waters using these were then dissolved using sulphamic methods have demonstrated the acid (200 mL of 10% w/v; BDH Lab ubiquity of Cryptosporiditm1 oocysts and Supplies, Poole, England). The plastic Giardia cysts in surface waters around carboy was then washed with 200 mL the world (Gilmour et al., 1991; Hansen of 0.01 % v/v of Tween 80 and the and Ongerth, 1991; LeChevallier el al, washings added to the dissolved floe.

The concentration was then 19916; Rose et al, 1991; Smith et al, 1991; Veal et al, 1995). The lack of completed and the concentrated standardisation between detection samples split. Half of each concentrated methods and the fact that results arc sample was sent to Macquarie often not corrected for recovery rates, University for flow cytometric analysis. makes it difficult to compare the results The other half was analysed at from these surveys. The aim of this Australian Catholic University by flotastudy was to compare the methods of tion. Both techniques used the same density flotation and flow cytomctry for epifluorescent monoclonal antibodies the detection of Cryptosporidi11111 oocysts specific for Giardia and Cryptosporidium.

Flotation. In a method similar to that and Giardia cysts.

WATER JANUARY/FEBRUARY 1997

9

WAT I: R Table 1 Number of occurrences of Cryptosporidium oocysts and Giardia cysts for the sites analysed by flotation and flow cytometry.

Site

Method

No. samples

Giardla

oocysts

cysts

0 0

Giles Creek

Flotation Flow cytometry

7 7

0 2

Devils Creek

Flotation Flow cytometry

9 9

0

0

4

1

Blue Eye Creek

Flotation Flow cytometry

2 2

0 0

0 0

West Moorabool

Flotation Flow cytometry

1 1

0 0

1

used by LeChevallier et al (l 991a). the dissolved floe was pelleted at I 050g for 10 minutes before layering on a Percollsucrosc (Sigma, St Louis, MO) gradient (density 1.100, 80 mL) and spun at 1050g for ten minutes. Cysts and oocysts were harvested from the gradient by removing the aqueous phase along with the top 5 mL of the gradient.

These were diluted in 0.01 % v/v of Tween 80 and pelleted for ten minutes at 1050g. Pellets were then stained with monoclonal antibody (CclLabs Diagnostics, Brookvale, NSW) by incubating for thirty minutes at 35°C. Cysts and oocysts were visualised using wet mounts examined with an epifluorescent UV microscope (400x) (Leitz SM-LUX, Germany).

Flow cytometry. Samples were stained with a monoclonal antibody (CclLabs Diagnostics, Brookvale, NSW). Samples were analysed using a Coulter Elite flow cytometer (Coulter Corp., Hialeah, FL, USA) using the method described by Vesey et al (1993b) which sorts particles on the basis of their size and fluorescence. Cysts and oocysts were sorted onto a target slide and examined using epifluorescence and DIC microscopy.

Identification. Giardia cysts (6-16 micrometres) and Cryptosporidi11111 oocysts (4-7 micrometres) were identified and confirmed by the presence of internal structures as noted under UV, DIC or light microscopy. Under epifluorescence, microscopy cysts and oocysts have the apple green fluorescence of the FITC labelled monoclonal antibody.

The microscopes for confirmation were of similar quality and the operators have similar experience in identifying cysts and oocysts.

Results Over a six month period nineteen samples were analysed (Table 1).

Cryptosporidi11111 oocysts were detected at concentrations of one or two oocysts per ten litres on six occasions using flow cytometry but were not detected at all using the flotation method. Giardia cysts 10

No. Positive occurrences Cryptosporidlum

WATER JANUARY/FEBRUARY 1997

1

were detected on two occasions using flow cytometry and on one occasion using the flotation method. The concentration of Giardia, in the sample found positive using flow cytometry and flotation, was five cysts per ten litres and seven cysts per litre respectively.

In the five samples where cysts or oocysts were detected using flow cytometry but nothing was found using the flotation method, the concentrations were: 0.1 oocyst/L on two occasions, 0.2 oocysts/L on three occasions and 0.1 cyst/L on one occas10n.

Discussion In this investigation, where parasite concentrations were very low, the flow cytometiy method was found to be more sensitive than the flotation method, suggesting that either cysts and oocysts arc lost during the flotation process, perhaps by adhering to the glassware or by adhering to contaminating material which then pulls them down the gradient. Another possibility is that contaminating debris masks cysts and oocysts during the detection and confirmation process.

The flow cytomctry and density flotation methods differ in their sensitivity, cost and processing time. The sensitivity of both methods is ultimately determined by the ability of the technician doing the microscopy to identify and confirm the presence of the parasites visually. The flow cytometry method provides a sample free of much of the interfering debris found in samples processed by other methods, making visual identification and confirmation simpler and more reliable.

The density flotation method of purification risks losing cysts and oocysts that may be attached to other particles during a Percoll-sucrose flotation step (Fricker, 1995) not present in the flow cytometry method.

Technicians using the density flotation method must visually locate and confirm parasites surrounded by debris of similar density and often having a

similar fluorescence, which was not separated during the flotation process.

The debris present on the slide also makes confirmation of fluorescent objects such as cysts and oocysts using internal structure more difficult, as the debris obscures the view of the suspect particle. This may further reduce the sensitivity of the flotation method.

Cost and sample processing time are factors to consider when deciding which method to use for analysing water samples. Flow cytometry offers greater sensitivity, reliability and through-put of samples, but the capital and maintenance costs of a flow cytometer with a cell-sorting facility are high. By contrast, sample analysis using the flotation method has much lower capital and reagent costs. Sample processing times vary for either method depending upon the quality of the water. Water samples having a high concentration of algae or sediments may require more than one flotation in order to reduce the pellet size to a reasonable level. Even after cleaning up samples using a Percoll-sucrose flotation, there are often high numbers of algae that oocysts. may mask cysts and Microscopy time is greatly reduced using flow cytomeny because much of the interfering debris is removed during the screening process when suspect particles are deflected onto a slide for visual confirmation.

The number of water samples taken from the creeks that had low levels of Cryptosporidi11111 oocysts suggests that low-level contamination may be endemic to the area. While Giardia cysts were not routinely recovered from water samples, they were regularly detected in stock animal droppings in the catchment area. The sporadic recove1y of parasites from the creek water suggests that some irregular events, such as rainfall or access of stock animals to the creek, may be responsible for washing cysts and oocysts present in manure into the creek or resuspending parasites sequestered in the sediments.

Acknowledgements This work was carried out at Macquarie University (as part of an Urban Water Research Association Catholic grant) and Australian University, Aquinas Campus. Special thanks go to the Central Highlands Water Authority and Australian Water Technologies.

References American Public Health Association (APHA) American Water Works Association, and Water Pollution Control Federation. (1989) Standard Metfzods for the Examination cf Water and Wastewater, eds. Clesceri LS, Greenberg A E, Tnissell RR, 17th ed., Washington, DC.

WA 'f IE R Ashbolt NJ, Veal DA (1994) Testing the waters for a redundant indicator. Today's Life Sci, 6(6):28-29.

Barer M R, Wright A C (1990) A rcvicw<:ryptn,pnridir1m nml wat<"r. l.f'tt A pp!

A:ficrobio/, 11:271-277.

Blewett DA, Wright SE, Cascmorc D P, Booth N E, Jones C E (1993) Infective dose size studies on Cryptosporidi11111 parv11111 using gnotobiotic lambs. TVat Sci Tcc/1110!, 27:6164.

Borcham PF L, Upcroftj A, Upcroft P (1989) What's new in giardiasis-cpidcmiological considerations. Proceedi11gs Ciardia: m1 emerging issue i11 water ma11ageme11t. The Centre for Continuing Education, The Australian Catholic University.

D'Antonio R G, Winn R. E, Taylor J P, Gustafson TL, Current W L, Rhodes MM, Gary G W, Zajac RA (1985) A waterborne outbreak of cryptosporidiosis in normal hosts. Ami l111cr 1Wed, 103:886-888.

DuPont H L, Chappell C L, Sterling C R, Okhuysen P C, Rose J B, Jakubowski W (1995) The infcctivity of C,yp1osporidi11111 panmm in healthy volunteers, New E11g J i\tled, 332:855-859.

Fricker CR (1995) Detection of C,yptosporidi11m and Giardia in water. In: Protozoan Parasites a11d TÂĽater, eds. Betts W B, Casemore D, Fricker CR, Smith H V, Watkins), pp 9196.

Gilmour RA, Smith H V, Smith PG, Morris G P, Girdwood R. WA (1991) The occurrence and viability of Giardia spp. cysts in UK waters. Wal Sci Tec/1110/, 24:179-182.

Hansen) S, OngerthJ E (1991) Effects of time and watershed characteristics on the concentration of C,yptosporidi11111 oocyscs in river water. Appl Emiiro11 Microbiol, 57:2790-2795.

Hayes E B et al (1989) Large community outbreak of cryptosporidiosis due to

contamination of a filtered public water supply. New E11g. j. lvled., 320(21):13721376.

Korich D G, Mead) R, Madore MS, Sinclair N A and Sterling C R (1990) Effects of ozone. chlorine dioxide, chlorine and monochloramine on C1yptosporidi11111 panm111 oocyst viability. Appl E1111iro1J Microbiol, 56:14231428.

LeChevallier M W, Norton W D, Lee R G (1991a). Occurrence of Giardia and Cryptosporidi11111 spp. in surface water supplies. Appl E1wiro11 1vlicrobiol, 57:26102616.

LeChevallier M W, Norton W D, Lee R G (19916) Giardia and Cryptosporidi11m spp. in filtered drinking water supplies. Appl E11viro11 Microbiol, 57:2617-2621.

Miller R A, Bronsdon M A and Morton W R (1990) Experimental cryptosporidiosis in a primate model.] bifect Dis, 61:312-315.

O'Donoghue P J (1995) Ciyptosporidi11111 and cryptosporidiosis in man and animals. Im J Pamsitol, 25 (2):139-195.

Pontius F W (1993) Protecting the public against Cryptosporidi11111. J Amer Wat Works Assn, 85 (8):122-123.

Poulton M, Colbourne J, Dennis P J (1991) Thames Water's experience with Cryptosporidir1111. Wat Sci Tech, 24:21-26.

Rose J B, Darbin H, Gerba C P (1988) Correlations of the protozoa, Crwtosporidi11111 and Giardia with water quality variables in a watershed. VJ/at Sci Tccli, 20:271-276.

Rose) B, Gerba C P and Jakubowski W (1991) Survey of potable water supplies for Ciyptosporidi11111 and Giardia. E1l!liro11 Sci Tec/i, 25:1393-1400.

Smith H V, Griniason AM, Benton C, Parker J F W (1991) The occurrence of Cryplosporidi11111 spp. oocysts in Scottish

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waters and the development of a fluorogenic viability assay for individual Ciyptosporidi11111 spp. oocysts. Wat Sci Tech, 24:169-172.

Veal DA, Faulkner B, Vesey G, Grohmann G (1995) Cryptosporidi11m: the cunning contaminant. Microbiol A11Slml, 16(3): 12-14.

Vesey G, Slade J S, Byrne M, Shepherd K, Fricker C R (1993a) A new method for the concentration of Cryptosporidi11111 oocysts in water using flow cytometry.J Appl Bac/eriol, 75:82-86.

Vesey G, Slade J S, Byrne M, Shepherd K, Dennis P J and Fricker C R (1993b) Routine monitoring of Cryptosporidir1111 oocysts in water using flow cytometry. J Appl Bacteriol, 75:87-90.

Authors Dr Robert Thurman is Senior Lect11rer a11d Head efi.\;Jaths, Science and Infor111atio11 Tech11ology at the Australian Catholic U11i11ersity (correspo11de11ce should be addressed to /zim at Aquinas Campus, Ballam!, Victoria 3350). He has worked i11 the area of water quality for 011er ten years.

Dr Duncan Veal is Se11ior Lecturer i11 Nlicrobiology at the Key Crntre for Biodiversity and Bioreso11rces at lvlacq11arie Uni11ersity. Alan Champion is a prefessional officer and at the time of the ilwestigatio11, Belinda Faulkner was a 1vlasters st11de11t, at the School efBiological Sciences at 1\tlacq11arie Uni11ersity.

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11

WATER

-

Technical

Note

CONTAMINATION OF SAMPLES FOR DOC ANALYSIS J van Leeuwen, M Drikas, D Bursill, B Nicholson Introduction In the analysis of total and dissolved organic carbon (TOC/DOC) in water samples, various methods are used to oxidise organic carbon to carbon dioxide which is then measured.

Analytical methods that incorporate different oxidation procedures include high temperature catalytic oxidation and persulfate oxidation with UV irradiation. Sources that have been reported to be possible contaminants in DOC analysis include the plumbing and/or catalyst in high temperature methods (Koprivqjak et al., 1995) and auto sampler vials (Kaplan, 1992).

For the determination of TOC and DOC in water samples, an auto sampler may be coupled to a detector instrument which allows for increased sample throughput. With the large number of water samples continually analysed for TOC and DOC at our laboratory, the use of an auto sampler has proven essential. On some occasions it was noted that blanks which had been on the autosampler carousel for several hours were noticeably higher than blanks analysed at the start of the run.

Several tests were conducted to establish the reason for this and the results are reported here.

Materials and Methods Concentrations of organic carbon in filtered (0.45 Tm) water samples were determined using a Skalar SK12 analyser (Skalar Analytical B V, Breda, The Netherlands) coupled to an auto sampler (Skalar 1000). Concentrations in samples were determined by comparison with freshly prepared

blanks and DOC standards (2 to 20 mg/L DOC as glycine in Milli-Q Plus water, Millipore Corporation).

Tests performed to assess contamination of samples arc as follows: • Ten Milli-Q Plus water samples (MQPW) were placed in sample cups (Cat. No. 1023, Skalar Analytical B V) and sealed with aluminium foil and 10 other cups were left unsealed. Samples were stored for 4 hours under a fume hood in an organic chemistry laboratory (OCL) where solvents such as methanol, hexane, acctonitile and acetone are commonly used.

• In a repeat test, samples were held in sample cups (Cat. No. 1022, Skalar Analytical B V) and either sealed with aluminium foil or left unsealed.

Samples were stored for 3 hours in a fume hood of OCL. • Samples of MQPW and a glycine solution (15 mg/L dissolved organic carbon) were stored for 4 hours in sealed or unsealed cups (Cat. No. 1022, Skalar Analytical B V) in a fume hood ofOCL • Samples (MQPW) were stored for 5 hours in vials (P N 22227, Disposable Products) capped or uncapped, in two other laboratories; one specialising in water treatment investigations (WTL) where organic solvents are infrequently used and another where routine analysis of industrial and domestic wastewatcrs ~ L ) is conducted. In the WWL, chloroform and a small amount of acetone are commonly used.

• Samples (MQPW) in vials, capped or uncapped, were stored outside of the laboratory for 5.5 hours.

All sample containers were made of

Table 1 Contamination of water samples following storage in sealed or unsealed containers.

Test

Water

Lab

No.of Replicates

DOC (mg,/L)

iu.l.u

YDl!H'Jlld Mean (5 D) Range

0.08 (0.08) *n d to 0.24

0.60 (0.14) 0.39 to 0.85

0.20 (0.11) 0.11 to 0.40

2.1 (0.25) 1.8 to 2.5

nd

0.44 17.0 16.6, 17.4

Mean (SD) Range I

Milli·Q

OCL

II

Milli-Q

OCL

6

OCL OCL

2 2

15.1

Ill

Milli-Q

Ill

DOC 15 mg/L

IV

Milli-Q

WTL

3

nd

0.37 (0.01) 0.35 to 0.38

IV

Milli-Q

WWL

3

0.02 (0.03) n d to 0.06

0.65

*n d , not detected

12

10

WATER JANUARY/FEBRUARY 1997

polystyrene and samples were either sealed before being placed onto the autosampler carousel or were analysed within about 0.5 hour.

Results and Discussion Concentrations of DOC (mg/L) in samples stored for 3 to 5 hours are shown in Table 1. Under the storage conditions used, no evidence was found of organics leaching out from the sample containers.

Clear differences were found between sealed and unsealed samples stored in laboratories, although variation in the degree of contamination was found on different days and between different locations. The highest contamination (2.1 mg/L) of Milli-Q water occurred in a fume hood of OCL where a number of volatile organic solvents are routinely used.

Sealed samples (MQPW) were also found to have higher concentrations of DOC (mean 0.2 mg/L) for this test, indicating that sealing had not been airtight. Nevertheless, this restriction resulted in a substantial reduction in contamination.

Although water samples are acidified and spargcd with nitrogen for removal of volatile organics and inorganic carbon prior to oxidation of organic carbon using persulphate and UV irradiation, the results indicate that organics which had partitioned into unsealed samples were not completely removed by sparging.

DOC contamination was not detected in sealed and unsealed MQPW that had been stored outside of the laboratory. The results indicate that aerial contamination of samples in a laboratory can occur prior to and during organic carbon analysis and that sealing of sample vials will minimise this contamination.

References Kaplan LA (1992) Comparison of high-temperature and persulfate oxidation methods for detennination of dissolved organic carbon in fresh waters. Li11111ology and Ocea11ogmphy, 37 (5) pp 1119-1125.

Koprivnjak J-F, Blanchette J G, Bourbonnierc R A, Clair T A, Heyes A, Lum K R, McCrea R, Moore TR (1995) The underestimation of concentrations of dissolved organic carbon in fresh waters. Water Research 29 (1) pp 91-94.

Authors John van Leeuwen, Mary Drlkas, Don Burslll and Brenton Nicholson

are all members cif the Australian Water Quality Ce11tre, Private Mail Bag 3, Salisbury, South Australia 5108.

WATER

Aquifer Storage and Recovery Aquifer storage and recovery of reclaimed water (ASR) is the process of injecting water into wells to recharge aquifers for subsequent recovery and use. For example, urban stormwater and treated wastewater can be stored below ground for use in dry periods.

The potential for developing irrigation quality water in urban areas is significant.

Australian experience has been limited to a few small-scale investigations. The CSIRO Centre for Groundwater Studies has initiated a program to explore the opportunities and the constraints.

So far, the centre has carried out two major initiatives: they have developed guidelines for the quality of water to be injected and they have run a two-day course on the subject.

The Guidelines These are guidelines on the quality of stormwater and treated wastewater for irtjection into aquifers for storage and reuse. These guidelines are quite different from those developed overseas, and have undergone a process of community and industry consultation. They summarise: • international experience and guidelines • information on the quality of urban run-off and treated wastewater in Australia • the effectiveness of wetlands and detention ponds for treatment prior to recharge • clogging and biogeochemical issues • data from a pilot study on the North Adelaide plains, where over 200 ML of stormwater has been stored in a brackish aquifer to provide a supply now suitable for irrigation • the principles on which sustainable ASR can be based.

National Short Course The centre organised two courses in October. Day 1 was for water users and there were 35 attendees. Day 2 was aimed at engineers and scientists, with 60 in attendance, including representatives from councils, government agencies and consultants.

The subjects covered by the 19 experienced presenters were: 1. What is ASR? International and local experience, ASR economics for users, feasibility.

2. Steps in developing an ASR operation-feasibility checklist, role of government and catchment boards,

water quality, environment protection, approval conditions.

3. Siting-where ASR is preferred, aquifer types and confining beds, groundwater quality, methods of artificial recharge, availability of water, sewer mining, demand and variations, examples.

4. Design-retention storage, wetland design for quality improvement, types of treatment, control systems, design of wells, modelling ASR effects, monitoring and groundwater protection, economics.

5. Operation-clogging, bio-geochemical reactions, attenuation of microorganisms, attenuation of chemical pollutants, recovery efficiency, operation of monitoring systems.

6. Conclusion-summary of experiences, unresolved R&D issues.

After section 2, a visit was organised to the Andrews Farm pilot site, where CSIRO is working in collaboration with Hickinbotham Homes (a developer) and the SA Mines and Energy hydrologists.

The system being trialed is a detention basin followed by injection into a limestone aquifer. It is part of a broader initiative by the developer to establish housing for 70,000 people with local re-use of both stormwater and treated wastewater.

As well as irrigation of local parks and gardens, the water could have use in the nearby Virginia horticultural area, which is currently over-exploiting the local aquifer. Other sites visited were Northfield and The Paddocks.

Copies of the guidelines can be obtained from Heather Bajcarz. Copies of the course notes can be obtained at a cost of$100, from Silvana Cammarano, Centre for Groundwater Studies, PMB @ Glen Osmond, 5064, facsimile (08) 8303 8750.

Report b]' Trevor Pillar

Kalgoorlie Water The WA branch's annual minisymposium this year took the form of a weekend in the mining centre of Kalgoorlie in late August. A total of137 people attended: 81 delegates (representing 40 organisations), 40 accompanying persons, and 16 children.

The event was coordinated by Ian Waite and his band of helpers, particularly Des Boland's programming subcommittee and sponsored by AEL (Australian Euvin.>1m1ental Laboratories), Western Mining Corporation, Water & Rivers Commission and Cleanaway Technical Services.

The conference gave an excellent insight into the complex issues involved

with providing an adequate and secure water supply to the Kalgoorlie region.

Sir Laurence Brodie Hall opened proceedings on the Saturday by discussing the history of water supply to the Goldfields. Phil Pyle (Water Corporation) followed by describing the rehabilitation of the Goldfields Pipeline. Phil Commander (Water & Rivers Commission) then gave a brief talk on Goldfields groundwater resources and the unique hydrogeology of the region.

John Collins (Western Mining Corporation) gave an address titled 'Water Management is Good Business' and described measures being taken to change water consumption culture in his company. WMC is the largest single user of water in the Goldfields & Agricultural Region water system.

Rod Botica (Water Corporation) and Dr Stuart White discussed water demand management in the Goldfields and spoke about ways and means of implementing water efficiency strategies which would earn Kalgoorlie-Boulder the title of 'The Water Efficient City' (see September-October Water).

Rick Staker (AEL) gave an overview of current trends in environmental analysis towards quality assurance. He reminded everyone that people serving people means quality.

Gavin Broom (Burns & Roe Worley) kicked off the afternoon session by discussing water supply options for industry in the region. Dr Tony McNnlty (Rust PPK) detailed a proposal to drain Lake Dumbleyung and its perceived benefits. Tom Stvattsott (GHD) & Ian Bruce (KCGM) co-authored the next paper on water harvesting options and looked at alternatives to using Hannans Lake for water supply. Pete,- MacIntosh (Occtech Corp.) discussed mineral processing using less water or industrial grade water. Peter Addison (Water Corporation) then led discussion on the day's papers and gave the concluding comments.

On the Sunday morning, an informative site visit to the PosGold Kaltails Tailings Retreatment Project was well received. The project involves the reclamation and retreatment of 60 million tonnes of gold tailings (the result of 100 years mining) over a nine year period.

During lunch, special guest the Hon. Roger Nicholls, Minister for Water Resources, made a presentation on behalf of the WA Government to the City of Kalgoorlie-Boulder as the first 'WaterWise' community in Australia.

WATER JANUARY/FEBRUARY 1997

13

WATER

Acid and Acid Sulphate Soils

Water Workshop

The first Womett in Water Workshop was held in early October at Old Government House, Parramatta About 35 people attended this NSW (NSW). The workshop, held to estabseminar of the IEAust Water Engineering Interest Group 111 lish WIW as an interest group within AWWA, was attended by about 30 October. The speaker was Dr Pam Hazelton from the University of people and generated a great deal of positive communication, enthusiasm, Technology, Sydney. and an actions list longer than the origiPam pointed out the significant nal agenda. difference between acid soils and acid Therese Flapper (CH2M HILL) sulphate soils. The former are naturally presented an overview of the possible occurring. They arc still a problem, activities and directives of the group since at low pH, corrosion of pipes can and initiated discussion to identify the occur. Acid sulphate soils are found group's principal objectives and interaround coastal areas of Australia (except ests. These were principally to raise the Tasmania). They occur in very specific profile of women and to encourage areas, such as near lakes and low lying more women to enter and stay in the areas where the sea has been cut off, or industry. in old swampy systems.

Chris Davis (AWW A Executive Exposure of acid sulphate soils is the Director) outlined his view of the problem for engineers, since the result necessary changes in the professional is oxidation of pyrites to sulphuric acid. sector as the 'market' has increasing numbers of women to interact with.

Pam cited the case of fish kills in the He expressed concern with the low Shoalhaven area being blamed on representation of women in AWW A industry, when it was due to the and in the industry and asserted construction of agricultural drains AWWA's interest in recognising the across the flood plain. This resulted in oxidation of pyrites and the resultant value of women in the industry.

Leeta Caiger (Analchem-Bioassay/ mobilisation of aluminium, which is Robyn Tuft and Associates) undertook toxic to aquatic life. At low pH, metals mobilise and are transported with water a 'group characterisation' which revealed a 50:50 split between flows. engineers and scientists, broad reprePam described some field indicators sentation across a range of industry of potential acid sulphate soils, includsectors and from O to 30 years of ing iron stains on soil surface (reddish experience in the water industry. colouring); very clear pools of water Savitha Bair, (CMPS&F) reviewed (after Al flocculation); red ochre the early years, suggesting that every(sludge mass) clogging of drains; one is responsible for their own profespresence of mangroves/melaleucas/ sional progress. However, working in casuarinas growing together; jarosite the industry could be easier with more oxidation (yellow). (any) female role models; a network for The impacts of acid sulphate 'female feedback' on ambiguous situaexposure are far-reaching. They range tions; recognition of 'life' priorities; from plant deficiencies, habitat destrncand acceptance of allowing for a family in long-term career plans. tion and environmental toxicity effects, An open discussion followed, coverto corrosion and deterioration in concrete structures, corrosion of boats ing everything from maternity leave and problems in estuarine mud (having and all its ramifications to job sharing, placing work in perspective with other low bearing strengths). life activities, effective stress and time The site must be assessed, in order to management and fostering an appreciaconsider developmental strategies. tion of the kind of contributions that Generally, this will involve geomorcan't be easily quantified, such as the phological surveys, sampling and analyhighly developed management skills of sis, followed by evaluation and pilot women who have been looking after projects to test the proposed managechildren, attitude, loyalty to the firm, ment. Pam also stressed the importance morale and 'people' skills. of implementing monitoring programs.

Lisa Raivlinsoti (Lisa Rawlinson and Typical management strategics: Associates) started the second session • avoiding any development at the site with a profile of her professional • preventing oxidation by ensuring experience. She outlined the difficulties the soil remains below the water table, and benefits of self-employment, or capping of soil if it is stockpiled highlighting the value of a supportive • neutralisation using lime husband, and the choice of freedom • bunding, collection of leachate and and its risks as opposed to conformity neutralisation. and security.

14

WATER JANUARY/FEBRUARY 1997

Guy Parker Award 'Drinking Water Quality and Treatment Requirements-A Risk Based Approach', by Stuart McConnell, Dr Melita Stevens, Dr Peter Nadebaum, Mike Chapman, Dr Sri Ananthakumar and Professor John McNeil, has won the annual Guy Parker Award for the best paper published in Water. All authors are from agencies which are partners in the CRC for Water Quality and Treatment and Stuart McConnell was team leader for the project. The paper was published in November 1995.

The award commemorates the memory of Guy Parker who played a major role in forming the association in 1962 and made significant contributions to the affairs of the association as a member, federal president and honorary secretary/treasurer.

Guy Parker was the foundation chairman of the journal committee and was responsible for the planning and development of Water from its inception until his sudden death in 1981.

Originality, relevance and presentation are the criteria used to make the choice. The award carries a cash prize of$500.

Doreen Clark (Analchem-Bioassay, Managing Director) described her climb to the top through a series of anecdotes. The principal points made were that opportunities for development should always be taken as a potential benefit; that progress will suit only some and not all, but that every little bit of support from the slightly sedentary will add to the effectiveness of the gogetters; and aim to maintain quality.

Glenda Sanders (CSIRO, Principal Scientist) explained the workings of the public sector and the presence of subtle (and not so subtle) inequities despite EEO. Interesting facts related included: employment selection processes unrelated to professional competence and difference in average pay for equivalent work (extra monetary compensation for married males on field trips due to the 'lack of amenity of a wife'!!).

Lisa Corby11 (EPA, Assistant Director General) discussed water, demonstrating the core quality ofinterest in your profession. Critical points made included: 40% proportion of females in executive positions in the EPA; the need to ensure that WIW is not about women only, but maintains the professional focus on the water industry. More discussion followed on the future activities ofWIW.

ENVIRONMENT

CATCHMENT MANAGEMENT WITHIN AGENCIES Where Bottom Up Meets Top Down J Howard Introduction

together, it is timely to consider Mitchell's (1988) key principle of 'process'. A general lack of'process' was recently identified in catchment management right across Australia (AACM 1995). One reason for this is the friction generated at the boundaries or edges of responsibilities and administrations (Mitchell 1988). I would like to continue the debate and suggest that the principal tools of corporate management-program planning, budgeting and performance appraisal-while offering greater opportunities for ministers and senior staff to reach down through administrative hierarchies, arc the basis for friction and therefore restricting the TCM process.

In New South Wales, Total Catchment Management (TCM) is defined under the Act as the coordinated and sustainable use and management of land, water, vegetation and other resources on a water catchment basis so as to balance resource utilisation and conservation. There are over 33 catchment management committees (CMC) and two catchment management trusts working in urban, coastal and rural areas covering 98% of NSW. Many of these catchment management committees are finishing or have finished plans designed to achieve sustainable resource use in each catchment.

They are now in the implementation phase.

Mitchell (1988) described TCM as involving three key principles: philosophy, process and product.

Clarke (1995) emphasised an additional item, the players.

Under TCM, everyone is a player: the various state government authorities, local government, industry, business and the community.

Total Catchment Management does not seek to change the role of each player, it is a partnership between landowners, the community and all levels of government (Clarke 1995). As catchment management committees are now implementing strate-gic plans, the focus is on the ways these players are working together.

If people are now being asked to work Curruthers Creek catchment

What is the TCM Process All About?

Integrated resource management is about coordination and cooperation. It is a relationship between participants that consists of shared and/or compatible objectives and an acknowledged distribution of roles and responsibilities. Catchment management committees have used this approach to solve a range ofissues: to reduce the amount of pollution being dumped into rivers, promote a conservation ethic amongst school children, increase recreational use of waterways, and to create demonstration sites for innovative technology.

In Canada, the Canadian Environmental Advisory Council (1991) recommended that cooperative natural

Photo: NSW Department of Land and Water Conse1Vation

WATER JANUARY/FEBRUARY 1997

15

ENVIRONMENT resource management requires: • agreement on clearly defined goals • mutual understanding, respect and support for each partner • recognition of the strengths and weakness of each partner • provision of adequate financial resources

• the ability to measure the effectiveness of the partnership • provision for joint decision making.

In general, cooperative approaches have many advantages. They allow participants to stay ahead of change, gain new sources of expertise and experience, get collaboration that multiplies efforts, allow concerned people to be involved, build consensus and allow representatives of those involved to build a commitment, to tackle problems that no one owns.

Is the Cooperative Process an Issue?

As part of the process of developing workshops for the 1996 NSW Grassroots TCM/Landcare Forum, a survey was sent to all catchment committee members. While the survey was designed to find out the broad issues that would be the focus of discussions, some of the responses show that 'process' is a matter of concern.

'TCM in my experience provides opportunities for discussion but little in the way of real contributions to better catchment management. The community members are often enthusiastic but lack expertise, while government agencies have technical skills but lack the commitment of their department to provide real time and resources to complete projects.'

'There is a need for closer cooperation between governments and CMCs to ensure consistency.'

'Dealing with bureaucracy can be a negative experience for individuals who may be highly motivated.'

'There is an unwritten assumption that the community cannot develop a big picture appreciation of the catchment.'

'Our plan was developed using an agency outline and the projects we proposed have a real purpose. We now want to play a role but the agencies appear unwilling to encourage this in practical terms.'

The partnership with local government was a focus for many, particularly those in urban areas: 'There is a need for overall coordination betvveen the cooperative approach and the maintenance programs of agencies, especially local government.'

'We need to look at more education of local government authorities, so sound decisions can be made.' catchment management Some committees have been very successful in 16

WATER JANUARY/FEBRUARY 1997

developing partnerships with local government. Lane Cove Catchment Management Committee was able to create a uniform schedule for declared noxious weeds across several local government areas. However, the issue of achieving particular objectives through a partnership with local government may always be a challenge as, unlike state agencies, local governments have many broad responsibilities.

Gaining acceptance and understanding of the TCM process will be difficult because of the administrative structure and the variety of disciplines in councils.

Cooperative Processes Meet TCM Planning There are three factors that occur in the TCM planning process that may make the proposed course of action weak.

• Tu,fism occurs where professionals attempt to protect their interests within an organisation. Often this is not deliberate. People who work in areas not requiring public consultation or formal public consultation periods (eg. policy) may not think of using catchment management committees. Others may simply be ignorant of the role and special knowledge of their agency's representative.

• Discords are disagreements over what should be done. Shared knowledge does not always lead to shared perceptions of problems and opportunities.

Professionals, often trained in certain ways of thinking and with certain experiences, may see priorities or ways of approaching problems differently.

Thus objectives, while agreed upon in the plan, may have differing perceptions or unwritten rules.

• Disjunction is simply explained as poor planning due to lack of knowledge. This usually occurs in TCM plans as a result of inadequate and inaccurate knowledge being made available to the committee. It erodes the credibility of the partnership from the very beginning as it shows a lack of trust.

Cooperative Processes and TCM Practice At the outset, it is important to realise that TCM has its limitations.

Improved catchment practices may depend on factors beyond a catchment management committee's role.

Taxation, exchange rates, legislation, media, community awareness, political will, and even climate, all affect sustainable resource management. Some issues require an entire system change with a mixture of social, economic, labour and health related strategies. Many catchment problems are also 'wicked'

problems. 'Wicked' problems are ill defined and rely on value judgement for resolution. Most of the parties involved are equally equipped, interested and able to judge the solutions, but there are no decision rules set down to determine 'correctness'. Judgements are likely to differ widely within a committee due to personal interest, value sets, past experience and ideology. Regardless of these limitations, there are some aspects of the way we manage the TCM 'process' that can be improved.

The conflict with corporate approach to management within an agency needs improvement. Corporatisation provides for program-based organisational structures. This process constrains the solving of wicked problems because decision makers, who may not actually be involved in the committee, will perceive advice, respond to consultation, and arrive at a decision differently to the participants. In addition, if a good corporate executive is one who makes incisive decisions leading to a clear cut course of action, then using the TCM 'bottom-up' approach may be perceived as procrastination or indecision.

Program-based management also makes it difficult to solve problems that no one owns. Complex issues may not be seen as core business. While total catchment management attempts to overcome this difficulty through the creation of partnerships, once again the good corporate executive may view the problem as being outside the objective or goal of the program being managed and decide not to resource the TCM approach.

Corporatisation also embraces performance based measurement. Such an approach is orientated towards achieving a specific outcome, weeding out repetition or overlap in responsibilities. However, TCM encourages participants to invent new solutions, create hybrid procedures and enter new environments with a high degree of cooperation. TCM is not about being in the midst of one agency's large campaign. As such, catchment management requires real statesmanship not measured performance. This can only happen when there is a commitment to empowerment and, explicit in this, is the possibility of mistakes by participants.

Program based planning is another issue. The more an agency is encouraged to think of itself as making and delivering products, the more likely its outputs will determine its priorities.

Priority tends to be given to activities which have quantifiable outputs. When the community has been defined as a 'consumer' in this way, it is difficult to justify broad multi-disciplinary and multi-stakeholder TCM approaches to organisational activities. Moreover,

ENVIRONMENT programs within the organisation arc seen as carrying out decisions made at the top, not by the community.

For example, participation has been said to be 'something that top orders the middle to do for the bottom'. The public are 'consulted' on major proposals and policy only through advertised exhibit periods. Complex issues and wicked problems cannot be adequately assessed by simply offering an initial opinion. Moreover, the history of this type of participatory approach has shown that some agencies have used manipulation, therapy, and placation to retain control of issues (Glass 1969).

Planning is a dynamic social process that includes discussion and negotiationrarely is it a rational one-shot process.

Finally, we arc yet to determine the best way for allowing a horizontal TCM approach to management (ie. bottomup-all players involved) to interact with a vertical approach to management (ie. top-down-program based structure).

Agencies must establish the ground rules and boundary conditions under which representatives are working: What can they decide? What can't they decide? What sort of resources arc available?

At present, TCM committees arc operating with limited funding and few constraints. This means that more time is spent defining the structure to achieve the task rather than actually allocating roles. Committees can flounder unproductively and members conclude they arc wasting their time. It might then be argued that increased funding would provide TCM committees with more power. However, past experience has shown that wicked problems cannot be solved by increased resources, indeed this would create another level of bureaucracy.

Managing the Process Better Implementing mechanisms that facilitate the development of improved catchment practices through TCM will take time and need a great deal of energy and nurturing. This is because the TCM philosophy requires both development within individuals as well as within organisations. It requires a fundamental change in the way we do business.

Clearly, agencies as a whole must become more educated about the TCM philosophy. Papers presented at conferences show that some professionals have a poor understanding of what integrated resource management means. It is not just sunply a geographical area or the 'integration' of land, water, vegetation and other resources. It is multi-dimensional: it crosses resource, discipline, and stakeholder boundaries. Moreover, the immense advantages this process has

in solving truly wicked problems needs to be promoted.

Perhaps one of the first steps involves developing common understandings and expectations between the catchment management committee and the agency in the presence of its representative. This might include agreement on common goals, sustained commitment, contribution of expertise and funds, and an active ongoing evaluation of the partnership.

Although attempts have been made from time to time to clarify roles and mandates, to date no one process or best model has been developed.

Some form of 'community contract' which included an outline of roles and responsibilities as well as a process of overseeing each agency's program within, a catchment, would overcome the problem of attempting to integrate the horizontal approach to management (i.e bottom up-all players involved) with the vertical approach to management (i.c top down-program based structure).

Related to this issue is the need to differentiate between the two possibilities of influencing decisions and participating in them. There is the need for some agencies to look at best practice in public consultation. There must be a genuine commitment to the consultation process involving listening to ideas and, where appropriate, adopting them.

Both the Institute of Planning Policy (sec Symc and Eaton 1989) and the NSW Office on Social Policy (1993) have produced guidelines for best practice in consultation.

Mechanisms must also be in place to allow communication across organisational boundaries. If catchment management is to be effective, other policy makers, leaders and planners within the different agencies may need to be involved. This means a mechanism to allow committees to move across set administrative rules, procedures and disciplines within the organisation. The principle is that improved catchment practices need different partnerships in different areas depending on the problem at hand. As the needs and resources change with the development and resolution of issues, new partnerships can be sought and new spheres of influence introduced.

Finally, the value of interactions and personal networks should not be underrated by agencies. It has to be recognised that creating networks is a fundamental part of the TCM approach. Sharing knowledge and improving services through networks constitute important information resources. For example, in Landcarc, several agencies and groups can be working on different aspects of the same problem and duplicating

results in many areas. Rather than copying the successful principles of one program and creating competition, we need to build on the processes already in place.

Conclusion Clearly the TCM process, which crosses program boundaries and attempts to create partnerships between organisations, poses a fundamental challenge to a tight corporate framework. Y ct it is becoming increasingly obvious that natural resource management is a team pursuit. Issues must be viewed in a wider social and economic context and often require cooperative approaches. Moreover, increasing community awareness demands a TCM participatmy approach. The challenge now is to integrate democratic, flexible approaches into an administrative structure, which unfortunately is also being asked to be more accountable and clearly structured.

The key to implementing the TCM process is therefore a paradox that attempts to manage a bottom up approach against a top down structure.

If we arc to achieve sustainable resource management, we now need to think about ways of modifying institutional processes to encourage everyone to work together.

References AACM (1995) Enhancing the Effectiveness of Catchment Management Planning. Final report for the Department of Primary Industries and Energy. AACM International Pty Ltd. Adelaide.

Burton J (1993) 'The Big Picture', My Point of View, Water. 20, 5.

Clarke A (1995) 'Ps in TCM-the Fuel of Change'. Water. 22, 4.

Canadian Environmental Advisory Council (1991) A Protected Areas Vision for Canada.

Ottawa: Minister of Supply and Services.

Mitchell B (1988) 'A Canadian Perspective on Integrated Catchment Management', in Working Papers for the National Workshop on Integrated Catchment Management, May 1988, pp 75-100. DepartmentofWater Resources, Melbourne.

Syme G J, Eaton E {1989) 'Public Involvement As A Negotiation Process'. ]011nwl of Social Issues, 45, 87-107 Office of Social Policy (1993) Better Service Through Consultation-Approaches to Consultation of Government Agencies.

NSW Government.

Glass] (1979) 'Citizen Participation in Planning: the Relationship Benveen Objectives and Techniques'. ]011mal ef the American lllstit11tc ef Plmmcrs. 45, pp 180-189

Author Jonathon Howard was the Co1111111111ity Education Officer for the Hawkesbury-t-.Jepea11 T111st, having previously been Bushland JV!a11age111e11t Officer at Kuri11g-gai Co1111cil. He is now a lecturer i11 Protected Area lV!a11ageme11t at Charles Stt,rt University (P O Box 789, Albury NSW

2640).

WATER JANUARY/FEBRUARY 1997

17

ENVIRONMENT

CONTROL OF CVANOBACTERIAL BLOOMS IN WEIR POOLS I T Webster, G J Jones, R L Oliver, M Bormans, BS Sherman Abstract This paper describes research work on the effects of river flows on occurrence of cyanobactcrial blooms in the relatively slow-flowing pools behind the regulatmy weirs on the MurrayDarling river system, and proposes a number of possible strategies to minimise such blooms.

The article is substantially the Executive Summa1y ofCEM Technical Report No.119, from the CSIRO Centre for Environmental Mechanics.

Copies of the full report (70 pages) are available from the Centre, GPO Box 821, Canberra, 2601.

Keywords Cyanobacteria, blue-green blooms, control of blooms, discharges, stratification

a_lgal nver

Introduction In recent years, blooms of toxic cyanobacteria A11abae11a circi11alis have been a problem in the Murray-Darling rivers. Although nutrients are certainly a basic requirement, the incidence of bloom formation has been observed to be related to river flows. This is particularly the case in the pools upstream of the regulatory weirs. For example, in 1992-93 it was observed that the numbers of Anabaena in the impoundment behind the Hay Weir were sharply reduced following pulses in the water flows.

An obvious explanation would be that the higher flow reduces the growing time, with the population being advected from one location to another. An alternative explanation is that low discharges fundamentally alter the physical environment within the pools.

This research project was based upon the latter premise: that within river weir pools, the flow velocities are sometimes so low that they are incapable of destroying the thermal stratification resulting from the absorption of solar energy close to the water surface.

Density (thermal) stratification has the effect of inhibiting turbulent mixing and may even suppress it altogether.

Under these circumstances, a population of buoyant phytoplankton such as 18

WATER JANUARY/FEBRUARY 1997

Anabaena will float into the well-lit water layer close to the water surface and so receive much more of the light necessa1y for its growth than a population mixed uniformly throughout the water column. We hypothesised that it was this mechanism that provides the main growth advantage to buoyant cyanobacteria under low discharge conditions.

Study Objectives The study had two objectives: • to investigate the effects of discharge

on stratification and mixing within weir pools and to investigate the resulting effects on phytoplankton population growth and the formation of cyanobacterial blooms • to devise and evaluate strategies for the control of cyanobacterial blooms based on the knowledge of the physical factors influencing cyanobacterial population growth and spatial distributions. The strategics investigated involve manipulation of the physical conditions within the weir pool by varying the discharge, modifying the discharge height, selective withdrawal, and artificial destratification.

Data Collection The study was carried out within Maude Weir pool on the Murrumbidgee River in central New South Wales. Although the height of the weir is only 6 m, due to the small river slope, the river backs up behind it as a pool to a distance of 35 km. Hay Weir, the next weir upstream, is located a further 40 km from the upstream end of the weir pool.

During the summers of 1993-1994 and 1994-1995, the weir pool was instrumented with three continuously recording thermistor chains in order to monitor its stratification behaviour.

Meteorological variables including wind speed, humidity, air temperature and radiation were also measured in order to gauge their effects on stratification. Water samples were collected one to three times a week for phytoplankton counts from a location near the weir. On occasion, additional samples were collected from locations further upstream and from depths through the

water column in order to describe the horizontal and vertical distributions of the phytoplankton populations.

Major Results 1. Based on measurements from this study in Maude Weir pool, and on measurements made in previous years in Hay W cir pool, it would appear that a necessa1y condition for the development of A11abae11a circi11alis blooms in these two weir pools is that discharge through the weir be less than about 1000 ML d- 1 for a period ofone to two weeks.

Growth of the Anabaena population occurred for discharges less than 500 MLd - 1, but there were no prolonged periods of discharge between 500 and 1000 ML d - 1 during the study so the limiting discharge for Anabaena growth is not known more precisely.

Concentrations of the dominant river phytoplankter, the diatom Melosira (Aulacoseira) granulata, were reduced under low discharge conditions, but this species dominated the summertime phytoplankton assemblage when the discharges exceeded 1000 Mid - 1• 2. The discharge through the weir gates was varied substantially during both summers to meet domestic and irrigation demands further downstream which allowed us to investigate the relationship between stratification of the water column in the weir pool and the discharge. When the discharge was less than about 1000 Ml d -l, the weir pool remained stratified day and night (persistent stratification), as shown in Figure 1. Discharges greater than about 1000 ML d- 1 caused diurnal stratification; that is, stratification was established and destroyed on a diurnal (day/night) cycle. Turbulence generated by the flow along the bottom of the weir pool eroded the stratification.

Winds over the river were generally weak due to sheltering by the continuous stand of trees lining both its banks and appeared to have little influence on the stratification status of the weir pool.

3. When the water column was persistently stratified, the Anabaena population accumulated in the surface layer (1 or 2 m thick) and the Melosira population became concentrated

ENVIRONMENT

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towards the bottom. The ratio of the near surface concentration of A11abaena to that at three or four 111 depth was usually ten or greater, but a ratio of over 50 was measured on one occasion.

These distributions arc consistent with A11abae11a having been positively buoyant and JVIelosira having been negatively buoyant when the water column was not actively mixing from top to bottom. A model of the relationship is shown in Figure 2.

4. Our measurements arc consistent with our hypothesis that it is mainly the separation of the populations within the water column under persistently stratified conditions which allows the A1zabaena population to thrive, and which causes the J\1elosira population to decline. The high turbidity in the river (- 10-35 NTU), resulted in a euphoric depth oflcss than 1.5 m, so that photosynthesis would have occurred in the top 30% of the water column only. The Anabae11a population in the surface layer would have had access to the light necessary for growth, whereas the Melosira would have experienced darkness as well as losses due to sedimentation.

5. Whether an A11abae11a population can grow to problem proportions will also depend on its residence time in the weir pool. For discharges above 1000 ML d- 1 , water moves through the weir pool approximately as a plug flow.

Residence times of algae within the pool are simply the volume of the weir pool divided by the discharge. At low

discharges when the weir pool is strongly stratified, the river flow into the upstream end of the pool flows along the pool at depth and out through the underflow weir. Under these conditions, the surface layer of the weir pool behaves as a long narrow lake. Such a surface layer containing an Anabaena population would have a very long residence time.

6. Although low discharge and persistent stratification usually stimulated vigorous growth of the A11abaena population in Maude W cir pool, they were not sufficient conditions. On one occasion (early summer 1995), discharge and temperature conditions appeared appropriate for a bloom to appear but none did. Interestingly, the bloom appeared to be developing, but the population suddenly 'collapsed'.

The reasons for this are unclear.

Possible explanations are nutrient limitation (due to lack of spring rainfall), predation by zoo plankton, or advcction away from the phytoplankton measurement site by westerly winds.

7. The best example of an A11abae11a bloom during this study in Maude Weir pool occurred during a five week period of persistent stratification in JanuaryFebruary 1994. The A11abae11a concentration near Maude Weir increased exponentially with time, with a specific growth rate of 0.37 d- 1 (doubling time roughly two days) for the first three weeks, then a relatively constant concentration for the next two weeks. It is probable that 0.37 d -I is similar to the true in situ growth rate for A11abaena, since the discharge was low and the advection of A11abaena along the weir pool would have been small. This growth rate is reasonably consistent with Aflabaena growth rates which have been reported elsewhere in the world.

With a specific growth rate of 0.37 d- 1 it took about three weeks for the A1zabaena concentration to increase from its initial value of 4 cells mL- 1 to the level 2 alert of 10 000 cells mL- 1 • 8. Nutrient bioassay measurements were made on a regular basis during the summer of 1993-1994. Only once

during the Anabaena bloom of January-February 1994 was there a weak suggestion of phosphorus limitation of phytoplankton function.

Nitrogen limitation was indicated during times of JV[elosira dominance before and after the Anabae11a bloom.

Unfortunately, the nutrient bioassays were not repeated the following summer to establish whether or not nutrient limitation played a role in the failure of the A11abaena population to bloom during that time.

Management Strategies The following points summarise our assessments of the management strategies we have considered for controlling cyanobacterial blooms in weir pools.

These assessments are based on our measurements within the weir pool and the predictions of a stratification model of the weir pool. The two-dimensional model describes the time evolution of the thermal and flow structures through the water column, and along the axis of the weir pool, as they respond to: meteorological forcing; the volume discharged through Maude Weir; and the temperature and discharge of the water flowing into the head of the weir pool. W c validated the model by comparing its predictions of the vertical temperature profiles at two sites along the pool with measurements made by continuously recording thcnnistor chains.

The model allowed us to test various management strategics for their impacts on the mixing regimes and residence times within Maude Weir pool. From these impacts, we inferred the likely effects on cyanobactcrial growth within the weir pool. Although our assessments of the utilities of the various management strategics for controlling cyanobacterial blooms in weir pools arc based on the simulations we performed for Maude Weir pool, we would expect that these assessments would carry over to other weir pools. An important caveat is that numerical values, such as the critical discharge for persistent stratification, are not likely to be applicable to other weir pools. However, the stratification model does provide us with the capability to estimate how such numerical values should be modified for other weir pools having differing geometries.

1. Maintaining the discharge through Hay and Maude Weirs at 1000 ML d- 1 would almost certainly eliminate the problem of Anabaena blooms in Maude Weir pool in summer. This conclusion is based primarily on measurements from this study. The critical discharge for Anabaena control in Maude Weir pool may be as low as 500 ML d- 1.

Factors which affect the critical discharge include the temperature of the WATER JANUARY/FEBRUARY 1997

19

ENVIRONMENT inflowing river water, the water level in the weir pool, and the solar radiation.

2. Pulsing the discharge through the weir pool represents a promising method for controlling A11abaena population growth at times when the average discharge (over time) must be restricted. For Maude, we suggest that a 1500 ML d- 1 pulse of a day's duration would easily be sufficient to mix the water column and restrain or reset cyanobacterial population development.

The pulse would be repeated at a regular interval. Optimally, the repetition interval would equal the inverse of the specific growth rate of the Anabaena population, which we infer to be about three days in Maude Weir pool, but repetition at longer intervals could still achieve the desired result of reducing population growth to below problem levels. This strategy of pulsing the discharge to control cyanobacterial blooms is sufficiently promising for it to be field tested. While a pulsed discharge strategy presents the river regulator with extra scheduling problems, it is not, from our assessment, an unrealistic prospect.

3. Based on the predictions from models of weir pool stratification and of withdrawal, it would seem that the degree of stratification within the weir pool under low discharge conditions would be similar if Maude Weir were an overflow weir rather than an underflow weir. However, the residence time of the surface layer in the weir pool, and hence the time available for the growth of an Anabaena population, would be substantially less than that for an underflow weir for discharges less than about 300 ML d -t The model-derived value of300 ML d- 1 for the upper limit of the effectiveness of an overflow discharge for minimising blooms should be regarded as rubbery; models are only approximations to real phenomena.

Siphons on the weir arc a means of obtaining an overflow discharge through an underflow weir. Tests on the efficacy of siphons for controlling cyanobacterial blooms were carried out, but the results of these experiments are equivocal. A major problem for us was the lack of appropriate discharge conditions-at the right time of the year-to test the siphons properly.

4. Under stratified conditions, Anabaena concentrations from depth within Maude Weir pool were usually measured to be a factor of at least ten less than those measured in the surface layer. Consequently, the strategy of withdrawing water for domestic consumption from the bottom of a stratified weir pool would be an effective strategy for minimising the concentrations of Anabaena in the Water supply.

Bottom water deoxygenation and 20

WATER JANUARY/FEBRUARY 1997

associated water quality problems high (hydrogen sulfide odours, dissolved manganese), did not occur.

The in-flowing water moving along the bottom of the weir pool seemed to have a short enough residence time to . in the bottom waters. maintain m,")'gen 5. Artificial destratification is a strategy which has been employed in reservoirs with the aim of reducing cyanobacterial growth. Destratification is usually accomplished with bottom mounted bubblers or by mechanical mixers. As a potential cost-effective strategy for minunising Anabaena blooms, the destratification technique deserves serious consideration. Based on our model simulations, we expect that the technique would reduce Anabaena growth rates by mixing the Anabaena through the water column in the vicinity of the destratification devices and by increasing the thickness of the surface layer. Artificial destratification has the potential to reduce significantly the discharge required to maintain diurnal mixing in the weir pool. It would also bottom waters remain ensure oxygenated.

Conclusions All five of the strategies we have examined in this study hold the prospect of minimising the occurrences or impacts of cyanobacterial blooms in weir pools. At this stage, increasing the discharge through the weir pool to beyond a critical level is the most certain way of preventing blooms, but such a strategy may prove to be unacceptable because of the volume of water required to be sent downstream. Nonetheless, our data enables economic trade-off analyses to be carried out for an increased base-flow strategy.

Withdrawing water from depth in the weir pool is a way of minimising phytoplankton concentrations in water supply during blooms of buoyant cyanobacteria such as Anabaena. The other three strategies considered, namely pulsing the weir discharge, withdrawing water over the weir wall rather than under it (using siphons), and artificial destratification, would all appear to be viable on the basis of their model predicted effects on stratification and surface layer retention times. These strategies should be field tested to confirm their effectiveness. Unfortunately, the tests we have carried out on the use of siphons are equivocal, due to a Jack of suitable stratification and cyanobacterial conditions during the time they were trialed.

The findings of this study further confirm our hypothesis that the occurrerlce of A11abaena blooms in weir pools has much to do with the onset of thermal stratification of the water column under low discharges. From

this study, we have developed the capaLility to model the stratification in Maude Weir pool as it responds to discharge. We are confident that we can extend this capability to other weir pools without difficulty. The potential exists to model the growth of phytoplankton populations in weir pools as well. Such modelling would provide a better understanding of the factors which lead to the occurrences of cyanobacterial blooms and would be very useful for the optimisation of some of the control strategies we have proposed.

The structure of a suitable growth model already exists, but we are missing crucial information for its application to Anabaena.

Required information includes this cyanobacterium's growth response to light and nutrients, its buoyancy response to physiological state, the origins and size of seed populations in weir pools, and loss mechanisms such as predation or photooxidative cell lysis. Laboratory studies are currently addressing some of these information needs. These studies need to be maintained and extended where they arc deficient. Ultimately, we need to test a model for Anabae11a growth in a suitable weir pool. Such a test would need to account for the nutrient dynamics in the weir pool and could very well be conducted in conjunction with tests of a cyanobacterial management strategy such as pulsing the discharge.

Acknowledgements Support for this study was obtained the National Resource from Management Strategy, from CSIRO, from the CSIRO Blue-Green Algal Program, and from the CRC for Freshwater Ecology.

Authors Dr Gary Jones is a phytoplankton ecologist at the CSIRO Division of Water Resources. Dr Miriam Bormans, Dr Ian Webster and Dr Brad Sherman are

physical linwologists at the CSIRO Centre for Environmental Mechanics. Dr Rod Oliver is an ecologist at the MurrayDarling Freshwater Research Centre. The latter four are also members of the CRC for Freshwater Ecology.

Apology We apologise for editorial confusion.

In the paper on POLLUTEC (Water November/December, page 29) the list of collaborators should have cited Melbourne Water (Waterways and Drainage), instead of Melboun1e Parks and Waterways, which is an entirely separate organisation.

ENVIRONMENT

SAMPLING AND ANALYSIS Of WATER Meeting the objectives of the Australian Water Quality Guidelines W Maher, C leGras, A Wade Introduction The task of designing an objective and meaningful water-quality monitoring program is an underestimated art.

Collecting data for its own sake cannot be justified, and a sampling program requires attention to the specific purpose of water-quality information needs. These needs should be benchmarked against a suitable reference, such as the Australian Water Quality Guidelines for Fresh and Marine Waters (AWQG, ANZECC 1992).

An effective monitoring program has three elements:

• devising a sampling design to deliver representative measurements • establishing sampling procedures incorporating adequate safeguards to protect the integrity of samples being collected • developing a rigorous analytical scheme that produces verifiably accurate results.

Users of water-quality monitoring results, water managers and regulators are increasingly reliant on the validity and applicability of results purporting to reflect real-world water quality conditions. They require information that is both representative of the water system being sampled (design of data collection and interpretation of results), and based on appropriately verified analyses.

Sampling and analysing water in an accurate and representative fashion is separate from the benchmarking processes that underlie the AWQG. This document currently gives little advice on how to acquire data in a way that can be compared with guideline values. We believe that the incorporation of protocol guidelines into the pending revision of the AWQG would help to remedy this deficiency.

Therefore, water-quality monitoring programs require both a judiciously designed sampling protocol which is firmly La~t:<l 011 prt:-<lt:fine<l objective~, and rigorous and transparent quality control and assurance in sample collection and analysis. This latter issue provides the major emphasis of this paper.

Users of information derived from analytical data may rely implicitly on the competence of laboratories in collecting and analysing samples.

Considerable social and political mischief can result from water managers and policy formulators basing their decisions on information that is rarely, if ever, questioned.

constraints imposed. Where circumstances dictate a limited range of management options, program objectives (and thus sampling strategy) must be framed in terms of distinguishing between the efficacy of these options.

In most cases, the process of program definition will assist in the development of an experimental protocol to allow the derivation of information, at the lowest cost consistent with acquiring meaningful data.

The clear definition of objectives can be assisted by developing a conceptual model of the system. Conceptual models can be depicted by simple box diagrams that show components and linkages. Once an agreed model of the system is made explicit, many problems in monitoring design are easily resolved.

A crucial issue in monitoring design

Being in the Right Place at the Right Time A summary of the considerations for designing a sampling program is shown in Figure 1.

The most crucial aspect in the design of a sampling program is a clear definition of the objectives of the study. This point may seem obvious, but an initial statement of the problem may determine whether a solution can be found within the logistical and financial PROBLEM / QUESTION

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Figure 1 Framework for design of sampling programs WATER JANUARY/FEBRUARY 1997

21

EIIIVIRONMEIIIT is establishing appropriate sampling intensity. (Figure 2). There are three major determinants of this: • the importance of the environmental value being protected. For example, protected, relatively undisturbed ecosystems may demand more intensive monitoring than degraded ones. This may be reflected in more rigorous recommended criteria for compliance with the guideline (the proportion of measurements permitted to be in excess of the guideline value).

• the proximity of ambient concentrations to guideline values. Where measurements demonstrate indicator concentrations which are consistently much lower than guideline values, resource commitment can usually be more modest.

• temporal and spatial variability in the system.

For the last two determinants, a pilot study can assist in deciding sampling intensity. For example, a pilot study to assess variability would measure transverse and depth heterogeneity for the relevant indicators. If variability in these dimensions were small, compared with site and temporal variability, acquisition of transect and subsurface samples could be reduced. This does not necessarily mean that they should be eliminated.

Another cause of variability, especially in physico-chemical indicators, is the occurrence of disruptive processes, such as rapid changes in environmental flows from extreme weather events. These events often cause large but transient excursions in the values of some chemical indicators. Whether these shortterm effects are significant in a particular case, depends on the definition of the environmental value to be protected and its sensitivity to acute exposure to elevated concentrations of these indicators. If transient excursions are judged to be important, then the sampling protocol must be systematised, or directed (rather than random) to ensure that they are included.

Another, but associated, issue in sampling design is to derive appropriate numerical values for comparison with a benchmark, such as the AWQG. To assess compliance with guideline values, it is usually necessa1y to carry out a statistical evaluation of the temporally and spatially distributed data. This may include hypothesis testing (for example, a null hypothesis that the guideline value has not been exceeded). The ability to accept or reject the null hypothesis within certain predetermined levels of probability is reliant on the number of samples analysed, how accurately the samples reflect inherent variability, and the integrity of the individual analyses. Approaches to the first two of these considerations are 22

WATER JANUARY/FEBRUARY 1997

discussed in the forthcoming ANZECC publication Guidelines for Monitoring and Reporting. Methods for ensuring analytical integrity are discussed below.

Returning Samples to the Laboratory Alive and Well The first step in validation of analytical data is quality control. This is defined here as devising procedures to minimise the intrusion of artefacts into the sampling and quantitation procedures. There are three components to quality control: • ensuring that a sample is representative of an adequately specified time and location. Examples of deficiencies in this regard include erroneous programming of automatic samplers; insufficient equilibration time for 'peepers'; inadequate site location; inaccurate depth specification; and non-representative sampling of surface microlayers for floating contaminants or organisms.

• minimising concentration changes in samples through contamination or analyte loss. Contamination and/or loss

Contalner Prepara!lon

may occur during sampling, transport, sample preparation and analysis. The most obvious way to compromise samples is through inappropriate (or inadequately prepared) collection vessels. Contamination during sampling can occur through inclusion of a component of the system that is not intended to be sampled, such as bottom sediment for depth samples of water, or surface films in the case of near-surface water samples. The collection of a water sample immediately downstream from a standing position, or metal-hulled boat, may also introduce contamination.

Inadequately preserved (for example, using acidification or a biocide) or sealed samples can result in loss of integrity during transport. The importance of a clean environment for transporting sample bottles (both to and from sampling sites) cannot be overemphasised.

• avoiding inaccurate quantitation in the laboratory. The most important shortcoming in the laboratory setting is sample contamination or analyte loss during sample preparation. Filtration

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ENVIRONMENT apparatus and 1nembranes can be important sources of contamination, if inadequately prepared. In the case of glass laboratory vessels, heavy metals can be adsorbed to the container wall, resulting in analyte loss. For organic carbon determinations, plastic filtration apparatus should be avoided unless it has been demonstrated that adsorption or desorption reactions do not occur.

Preparative media, such as solid-phase adsorbents, must be rigorously decontaminated before use. Any reagents (including acids), which are added to samples as part of the analytical procedure, are potential sources of contamination. Even high-purity chemicals can occasionally be contaminated with the required analytc, in most cases through inadequate storage.

Even where samples have not been compromised, inaccurate analyses can be returned through poor calibration or malfunctioning equipment. In these cases, highly reproducible (and therefore misleading) results may nevertheless be obtained. The performance of the analytical apparatus is critical to the integrity of data. All aspects of instrument function, including intra-run variability (which is often neglected), must be the subject of a regular calibration and maintenance program.

How To Be Sure That Quality Control Has Worked The second step in the validation of analytical data is quality assurance.

Quality assurance protocols determine the effectiveness that quality control measures. There are three main qualityassurance tools: 1. The incorporation of blanks at each stage of sampling and analytical procedures. The need for laboratory

reagent blanks is universally accepted in analytical chemistry. These arc usually aliquots of high-purity water that are treated as though they were samples.

This includes being subjected to the same sample-preparation procedures and reagent additions as authentic samples, including interim storage in sample containers. Where blank contamination is detected, blanks arc withdrawn progressively from procedural steps until the problem is no longer evident. Filter membranes and apparatus (particularly syringe filters) and sample bottles are common sources of contamination if inadequately prepared, as arc previously opened and inadequately stored containers of reagents.

Less commonly observed is the need for field blanks. These again arc usually sample containers of high-purity water which are transported to the field under the same conditions as containers to be The Essence of Quality Control used for samples. They should be The first essential requirement of opened at the sampling sites, preserved quality control is a critical evaluation of in the same way as samples, and transpossible sources of contamination and ported to and from the laboratory in analyte loss. This necessitates the identical fashion. Apart from contamiconstruction of a plan of sampling, nation derived from chemicals used for sample preparation and analysis, where preservation, a possible and largely every step, from container preparation unremarked source of extraneous to the operation of analytical equip- analyte is contamination of the outside ment, is explicitly identified and written of the sample container (including the down (Figure 3). thread of screw-topped bottles) being The next requirement is to devise transferred to the sample on decantaprocedures to minimise loss of analytical tion. To avoid this possibility, sample or sample integrity at each step. These bottles should be transported inside a must be codified into protocols which clean container or plastic wrap, and an arc clearly expressed and whose imple- aliquot for analysis withdrawn using a mentation is not either impractical or pipette. Where feasible, the outside of unnecessarily onerous. The protocol bottles should be washed with highshould include chain of custody purity water after return to the laboradocumentation. The inclusion of field tory. Field blanks are therefore compleand laboratory staff in the identification menta1y to laboratory procedural blanks and codification of procedures is essen- and help to diagnose the source of tial. In this way, special expertise is contamination when samples are incorporated into protocols, and a sense observed to be compromised. of ownership is engendered. A corollary 2. The acquisition of replicates at to this is that all procedural steps sample sites. For the purposes of (primarily consisting of field and labora- chemical analysis, replicates are samples tory notes, and machine print-outs) where the true variance between should be retained for evaluation in the samples is expected to be negligible. case of a problem being detected.

This requires that replicates be as The final requirement 1s proper temporally and spatially identical as instruction of staff who are required to possible. In most respects, replicates collect, transport and analyse samples serve the same function as field blanks.

This includes not only the mechanical Where they differ most significantly is aspects of procedures, but also a detailed in their ability to detect differential loss explanation ofwhy each step is important. of analyte between samples. They are

most valuable in detecting differences in preservation of samples, variable analytc loss during sample preparation, and intra-run performance changes by analytical equipment. This latter application of replicates requires that they be distributed randomly through the sample suite.

Replicates are most useful to infer random errors, as manifested by variability between replicates. The detection of systematic errors, leading to incorrect concentrations of similar magnitude, can best be achieved by using different operators to replicate the sampling (on a pilot basis). This comparison would be made more general by the use of differently formulated operating procedures between the teams.

3. The use of 1 independent' analytical comparisons. A widely used

method of comparison is the use of reference or control matcrials('comparison samples') during analysis. Most certified reference materials are expensive and only verify the accuracy of calibration and broad instrument reliability. They arc useful to assess intra-run variability, but repeat determinations of any sample containing sufficient analyte is adequate for this purpose. Reference materials cannot assure the integrity of sampling, transport, preservation and preparation procedures, unless they are introduced at the beginning of a protocol, in similar fashion to field blanks.

The same comments can be made for control materials. The latter are references prepared by individual laboratories for their internal use. Analyte concentrations arc determined soon after preparation. Variability in these values is monitored for the life of the material, during which time different calibration standard preparations, equipment operators and analytical techniques would in most cases be used.

The authenticity of control materials can be enhanced by involving other laboratories in their characterisation.

Unacknowledged differences in matrix composition between comparison and unknown samples can result in unjustified confidence in analytical results. An example of a deficient appreciation of this potential source of error is the use of low-chloride standard and reference solutions in the graphite furnace determination of lead, where the unknown samples contain elevated concentrations of chloride. The simplest remedy for potential matrix effects is to use a verified method of matrix modification. Where a suitable modifier is not available, it may be necessary to determine the behaviour of a known addition of analyte.

However, where the analytical method is dependent on the chemical form of the analytc, additional care must WATER JANUARY/FEBRUARY 1997

23

ENVIRON II/I ENT be exercised. Either the standard addition must be presented with same speciation as exists in the sample, or where this is impractical, sufficient time must be allowed to reach equilibrium.

This assumes that the kinetics are sufficiently rapid, and that reactants are available in the sample to allow the required speciation to be attained.

Where the specific chemical identity of the analyte is important (such as arsenic compounds in ocean or groundwater), but the speciation, kinetics or composition of the sample are not known, then recoveries near 100% must be considered obligatory to permit confidence in the accuracy of the analysis.

Interlaboratory comparison of unknown samples is a useful means of checking instrument performance and calibration accuracy, and many such programs are sponsored by testing authorities. However, few of these exercises involve extensive sample preparation, and fewer, if any, the 'downstream' processes of container preparation, sampling, preservation and transport. More value would be derived from 'round-robin' analyses if 'raw' samples (that is, those requiring extensive preparation before analysis) were included in programs. This could be accomplished for complex samples only if they were stable in the medium term and had a low degree of heterogeneity.

This. may limit their applicability to multi-component solutions that, for example, required digestion, separation or preconcentration prior to analysis.

A useful extension of interlaboratory comparisons is possible when more than one organisation has an interest in monitoring and assessing the environmental value being considered. In this case, replication of samples can be broadened to encompass every step of the sampling and analysis exercise.

Conclusions Water managers and regulators, and others with an interest in environmental values associated with water quality, are now supported by indicative guidelines.

These provide advice on the concentrations of chemicals that may lead to degradation of the value.

However, it is not straightforward to sample a defined aquatic system, or even a discrete water body, with a view to establishing compliance with a guideline. There are three important facets to the task: 1. A decision must be made on which indicators are to be determined, how frequently samples are to be taken, and the temporal and spatial distribution of sampling. The main objective of sampling design is to assess the variability of indicator concentrations in a way tha~ c~n be meaningfully analysed using statistical tools. To this end, the relative 24

WATER JANUARY/FEBRUARY 1997

contribution of possible sources of variability-such as transverse and depth gradients, temporal change and the relevance of short-term disruptive events-should be measured using a pilot study.

2. To avoid contamination of samples or loss of analyte in transit, a technical protocol for field activities must be devised. This requires the incorporation of appropriate quality control and quality assurance measures, proper training of field staff, scrupulous adherence to written procedures, and adequate documentation of activities and chain of custody.

3. A rigorous scheme of preparative and analytical procedures must be implemented. The incorporation of laboratory procedural blanks into the sample suite, in addition to field blanks, is mandatory. The use of reference or control materials of known concentration is recommended, to verify the accuracy of calibration and instrument performance, but the limitations of these tools must be recognised. More value can be obtained from comparison samples if they are included with field blanks, before sampling trips. lnterlaboratory comparisons, or the use of more than one analytical technique where available, can also increase confidence in the integrity of analyses.

Where matrix interferences exist, matrix modification that is documented to be effective should be employed.

Although the method of standard additions can usefully minimise matrix interferences, the technique has deficiencies where an aspect of the analytical procedure after spiking is dependent on the chemical form of the analyte.

Where speciation is important, spike recovery near 100% is necessary to verify that the sample components are capable of converting the addition to the required form in the time scale of the procedure.

Authors Dr Bill Maher is a11 e1wiro11111e11tal chemist at the CRC for Freshwater Ecology, University of Canberra, PO Box 1

Belco1111e11 ACT 2616.

Dr Chris leGras is a senior erwiro11-

me11tal chemist with the E11viro11111e11tal Research Institute of the Supervising Scientist. He is mainly co11cemed with environmental che111istty research aimed at protecting the heritage values of Kakadu National Park, with an emphasis on the effects of mining. He is presently i1wol11ed with re1Jisi11g the ANZECC Water Quality Guidelines.

Dr Alan Wade is with ACTEW. He

is experienced in both public health and environmental regulations, and has been involved in preparing the national water quality guideli11es since the early 1980s.

A workshop on 'Sampling Nutrients in Aquatic Systems' has been o,;ganised for 21 to 22 April, 1997 at the Univmity of

Canberra. Papers are ilwited and abstracts are required before 31 January 1997. For further ilifor111atio11 please contact Bill l\llaher at the CRC for Freshwater Ecology, University of Canberra, 1

PO Box 1, Belconnen, ACT 2616.

Tasmanian EMS Seminar a Success Speakers from industry, consulting services and their regulators presented their views on environmental management and auditing systems (EMS) under ISO 14001, at an AWWA seminar held 111 Launceston last November. Over 120 delegates attended what was the largest AWWA activity held in Tasmania for many years, indicating the high level of interest in the area.

Representatives from ICI Australia, the Hydro-Electric Corporation, Federal Airports Corporation, Australian Paper and the Quality Society of Australasia outlined the progress and importance of each organisation's EMS system.

An engineering consultant described the environmental and financial benefits of a 'mini' EMS approach appropriate for smaller industries. EMS can be used in the integration and coordination of various disciplines and sciences involving soil, vegetation, heritage and cultural factors with water engineering and water ecology.

An historical perspective on best practice environmental management, highlighting the relative nature and links with best practise in the 1700s, was presented by a representative from the Department of Environment and Land Management (DELM). Clearly, there have been massive improvements since then but further progress is needed.

The benefit of linking into, rather than duplicating, quality assurance systems under ISO 9000 was discussed.

Delegates also learned about how to become registered as a certified auditor under ISO 14000 through the Quality Society of Australasia.

A panel of speakers was questioned on various issues including the matter of self regulation utilising EMS and certification, as well as Australian companies and EMS in developing countries.

The seminar was initiated and subsidised by the Commonwealth EPA and supported by DELM, IEAust, and the Waste Management Association of Australia.

WASTEWATER

PETWIN™-A MODELLING TOOL

FOR THE PETROLEUM INDUSTRY

A J Baker Abstract PETWIN™ is a dynamic mechanistic model developed to assist petroleum/ petrochemical facilities with design and operation of their biological wastewater treatment plants so that effluent objectives can be met. Lack of information and understanding of system response often results in time consuming, costly mistakes. A simulation tool helps both designers and operators to make more effective decisions so that many of these mistakes can be minimised. In our ever more stringent regulatory environment, minimisation of these potential problems is critical.

Key Words Wastewater treatment, petroleum industry, modelling, activated sludge

Introduction The use of computer models has transformed the analysis and operation of the water industry by providing a means to predict the response of a 'system'. Models are available for modelling groundwater systems, surface water systems such as lakes and rivers, sewage discharge outfalls, and wastewater treatment plants, t9 name a few.

Models for municipal wastewater treatment systems have been used successfully for over 20 years, but significant differences in the nature of the two types of wastewaters have prevented the application of the municipal model to the industrial systems. To illustrate some of the differences between the municipal and industrial wastewaters, Table 1 compares typical influent data for the two wastewaters.

This paper presents a model called PE TWIN™, developed at McMaster University, Ontario Canada. PETWIN™ was developed to simulate the behaviour of biological wastewater treatment systems treating industrial wastewaters, specifically those from petroleum and petrochemical facilities.

The model was developed in conjum:tion with the petroleum and petrochemical industries in order to address the issues of direct concern to these industries.

PETWIN™ is a dynamic mechanis-

tic model. It consists of a set of nonlinear differential equations, each of which mathematically represents a reaction occurring in the treatment system. Solving these equations (simultaneously) generates the response of the treatment system for the given configuration and operating conditions. By mimicking system behaviour, PETWIN™ may be used as a tool for design, upgrading and retrofits, optimisation, and education and training programs.

Alternate operating modes of the wastewater treatment plant may be tested using the model to identify configurations which tend to produce a better quality effluent, or to identify any 'failure' modes before application to a full-scale system. Any subsequent experimental work, pilot testing, or full-scale testing can then be limited to viable options. This approach tends to minimise potential negative impacts on the full-scale facility and enables operators and engineers to achieve a better operating plant in a shorter time frame.

PETWIN™ was specifically designed to predict response in activated sludge systems, but applications to lagoon situations have also produced successful results.

This paper presents the development and application of PETWIN™ in three parts: development of the model; using the PETWIN™ model; examples of PETWIN™ applications.

The aim of describing each of these areas is to further the understanding not only of the application of PETWIN™ and how to maximise its benefits, but the nature of petroleum/petrochemical wastewaters and how they arc treated in biological treatment plants.

PETWIN™-Model Development PETWIN™ is a dynamic mechanistic model which was developed by identifying the components and processes which are important for describing the behaviour of a petroleum/petrochemical wastewater biological treatment facility. Each component in these wastewaters undergoes its own tra11sfurr11ation, and it is the nature of the compounds and associated reactions which control the behaviour of the wastewater treatment plants.

Development of PETWIN™ is

aimed at providing: • a framework for collecting infonnation on system behaviour • a framework for analysing system behaviour • a tool for understanding the interactions of system elements • a base to extend the model's ability to predict system response i.e. increase its complexity • a training tool or educational instrument.

Comprehensive review of existing plants ensured the practical nature of the model. By completing an experimental programme and discussing plant operations with staff at existing petroleum/petrochemical facilities, the following 21 components are represented in the model.

Biomass components. Heterotrophs (ZDH), nitrifiers (Z 8 N), and sulphur oxidisers (Z 85) arc included as the active components of the biomass. An endogenous mass component is also included to account for the unbiodegradable fraction of the reactor solids that results from the decay of organisms.

Organic components. The total concentration of organic material in the wastewater is quantified by its COD concentration. Individual components arc represented as fractions of the total COD and monitored according to the reactions they undergo in the system.

Figure 1 illustrates the breakdown of the influent organic material. The influent COD is firstly broken into biodegradable and unbiodcgradablc fractions. The biodegradable fraction is further subdivided into the following: phcnolics COD (SPH); hydrocarbon COD (SHc); volatile COD (Sy); mixed COD (SM); particulate COD (X5); user defined COD (S 00 ).

The unbiodegradable fraction is divided into soluble (S 1) and particulate (X 1) forms since each goes through different processes in the reactor.

Nitrogen components. The total influent nitrogen (TKN) is divided into ammonia (SNH) and organic nitrogen forms (S 0 N) as illustrated in Figure 2.

The model also includes nitrate nitrogen (SN 0 ) to track the nitrification process in the systems.

Sulphur components. The sulphur species included in the model are reduced sulphur compounds (Ssn) and sulphate (S 50 ) as illustrated in Figure 3.

WATER JANUARY/FEBRUARY 1997

25

WASTEWATER Reduced sulphur compounds are included as the oxidation of these compounds can have significant impacts on the m,"ygen . requirements in the system. The product of this oxidation is sulphate.

Miscellaneous. Additional components included in the model are soluble phosphate (Sp) which is required for growth of microorganisms, and oxygen (S 0 ) which is required for aerobic growth of biomass.

As an example of the difference between typical municipal wastewaters and petroleum based wastewaters, Table 1 lists the different influent fractions which are indicative of these influents.

This table illustrates the increased complexity of industrial systems compared to municipal systems. Many of the parameters in PETWIN™ are not necessary when modelling municipal systems. However, this situation may change as the industrial component of municipal wastewaters increases.

As for any model, it is important that the fraction of each component in the wastewater is identified in order to get an accurate representation of system response. Influent characterisation is an important part of model simulation and will be discussed in the next section.

For each of the compounds listed in Table 1, there is a corresponding reaction process which it undergoes in the biological treatment system to remove it from the wastewater or convert it to a less toxic compound.

Each reaction is represented as a mathematical equation. These equations form a set of nonlinear differential equations which, when solved, produce predictions of the behaviour of each compound incorporated in the model.

There were 20 processes required in the PETWIN™ model to appropriately simulate the response of these petroleum systems. These include: • aerobic growth of heterotrophs on different types of COD • anoxic growth of heterotrophs on different types of COD decay ofheterotrophs hydrolysis of particulate COD • adsorption of hydrocarbon COD • volatilisation of volatile organic COD • hydrolysis of particulate organic nitrogen • conversion of organic nitrogen to ammonia nitrifier growth nitrifier decay sulphur oxidiser growth • sulphur oxidiser decay • sulphur oxidation (biologically and chemically).

Each of these processes has a set of rate constants which was quantified during model formulation. An experi26

WATER JANUARY/FEBRUARY 1997

mental programme, consisting of simple batch tests, quantified many of these parameters during model development, while others were determined from past experience with biological treatment systems. The set of parameters currently in PETWIN™ were capable of producing a simulated response of two existing petroleum activated sludge systems and now act as default parameters.

Table 2 lists some examples of

stoichiometric and rate constants which were determined during formulation of the PETWIN™ model. As a comparison, values for similar model parameters in the municipal wastewater treatment model, BIOWIN™, are included.

Many of the parameters incorporated into PETWIN™ were not necessary in BIOWIN™.

As indicated, the parameters determined during development of the

Table 1 Typical influent factions for the municipal wastewaters versus petroleum wastewaters Influent Faction Parameter

Municipal Wastewater

Readily Biodegradable COD (fbs) Biodegradable particulate COD (fenm) Phenolics COD (fPH} Volatile Organic Compound COD (fv} Hydrocarbon COD (fcH) Mixed Compound COD (fM} Unbiodegradable Soluble COD (fusl Unbiodegradabel particulate COD (F upl Fraction of TKN which ammonia (fnal Fraction of Influent Sulphur which is Sulphide (f5R) *N/A represents Not Applicable

Petroleum Based Wastewater

0.16 0.57

N/A*

0.015 0.24 0.23 0.26 0.065 0.19 0.015 0.9 0.28

N/A N/A N/A N/A 0.12 0.15 0.61

N/A

Table 2 Typical stoichiometric and rate constants for petroleum wastewaters compared to municipal wastewaters Model Parameter Yield of Biomass on COD Maximum Growth Rates (µM)

PETWIN'"'

BIOWIN""

0.555-0.600 1.5-4.3

0.666 3.2

(Depends on compound) Growth Saturation Constraints (K5}

1.5-4.3

3.2

(Depends on compound)

Inhibition Constraints (Ki) Nitrifier Growth Rate Endogenous Decay Rate Volatilisation Rate Ammonification Rate COD:VSS Ratio

N/A

60 0.36 0.53 60 0.06 1.42 3.5

COD:VSS

0.50 0.62

N/A 0.032 1.48

N/A

Table 3 Comparison of three operating modes for an aerated lagoon system treating petroleum refinery wastewaters Parameter

Current System SRT =5.9 days

Option 1: SRT = 25 days

Option 2: SRT =50 days

138

20.1

25.5

33.8 5.5 2.7

27 0.6 11.1

26.9 0.6 12.1

2.6 138

3.3 274

3.4 351

Model Effluent Effluent Suspended

Solids (mg/L} Soluble COD (mg/L} Ammonia (mg/L-N) Nitrate (mg/L-N)

Lagoon

OUR (MG/L/hr} MLSS (mg/L/}

Table 4 PETWIN'" steady state simulation results for a petrochemical waste water treatment plant. Both systems were operated at an SRT of 38 days with Option 1 having a MLSS of 1638 mg,'L and Option 2 an MLSS of 565 mg,'L Cone. mg/L

COD

Sol

(Part)

COD

Effluent from Option 1

21.4

1277.8

17

Effluent from Option 2

49.5

312

36

TSS

vss

TKN (Sol.)

NH 3 • N

Nox·

15

35.6

0.1

12.0

10.0

10.4

35

0.9

0.3

38.1

7.4

8.4

N

P04

•

TP

p

WASTEWATER model act as the default parameters in the PETWIN™ model. It is important to note that while these parameters will produce simulations which approximate system response in any petroleum or petrochemical system, it is important to validate them for the system being evaluated. To be most effective, a certain amount of quality input data is required to validate model parameters.

This ensures that model simulations will tend to reflect the true response of the system under study.

Certain parameters, such as nitrification rates, arc system specific and certainly need to be checked. This is TOTAL ltiFLUEtlT

ORGANIC COD

especially true in industrial wastewaters, where certain influent compounds can inhibit the nitrifier activity, causing discharge of excess ammonia levels to receiving waters.

Also, if certain compounds of interest not incorporated in the original model are to be included in the PETWIN™ model as a 'User Defined Component' then its degradation rate needs to be quantified. PETWIN™ was formulated to allow for such flexibility.

Many of the experimental procedures used to develop the original model formulation can be performed as small pilot studies to determine these rate parameters and calibrate the model to the system under evaluation.

Calibration of the model to local conditions is an important aspect of using any model and will be discussed below.

UHBlODfGAAOABLE

Figure 1 Petroleum refinery wastewater characterisation of the total influent chemical oxygen demand

TOTAL INFLUENT TKN

I

SNH

SON

Figure 2 Petroleum refinery wastewater characterisation of the total influent kjeldahl nitrogen

TOTAL INFLUENT SULPHUR SPECIES

I

SSA

Sso

Figure 3 Petroleum refinery wastewater characterisation of the total influent sulphur species

Using PETWIN™ PETWIN™ is a PC based model which operates in a Windows environment. It enables the user to build easily a representation of a biological waste water treatment system and simulate the response of this system to a selected set of influent and operating conditions.

The following steps indicate the procedure for using the model: • establish some preliminary designs • specify the process units and flow scheme of the system • estimate the size of process units • input the operations parameters, i.e. return activated sludge rates, wastage rates, influent concentrations and flows, temperature, oxygen concentrations • simulate the system in steady state conditions simulate the system under dynamic conditions • compare effiuent results with desired output • alter physical and operational parameters and re-simulate. Repeat these modifications until the conditions which provide optimum results .i.re identified (i.e. meet effluent objectives, optimise costs).

An example of a biological wastewater

treatment system operating at a petrochemical refinery is illustrated in Figure

4.

The advantages of using a tool such as PETWIN™ are achieved by performing a range of model simulations to determine the most appropriate treatment system. If a new system is being designed, then a number of different system configurations and operating conditions can be tested on the model.

If an existing system is being analysed, different operating schemes can be considered. In either case, the model provides an effective means to predict system response for the different scenarios. The information gained from these simulations then provides direction on how to best operate the treatment plant to achieve the desired results.

As suggested earlier, one of the most important sets of parameters to determine when applying the model to a particular treatment facility is the nature of the wastewater to be treated. The model has been written in terms of COD components so it is necessary to identify the contribution of the various contaminants in the wastewater in terms of their COD fraction. Since different compounds undergo different reactions in the treatment system, they influence the response in different ways. The groups of parameters that PETWIN™ currently models were identified earlier.

If this data is not available from historical plant operating data, it may be necessary to perform some simple experiments.

Each reaction in PETWIN™ has an associated set of rate parameters which have been quantified in earlier studies.

As pointed out earlier, these default rate parameters provide excellent estimates for the rates of the different reactions in the system, but the more information that one has specific to the system under study, the more reliable the results.

PETWIN™ is written to enable the user to adjust these rate parameters as new data is collected.

Calibration of PETWIN™ to the local conditions is an essential part of using the model and achieving the most successful results. Similar work with municipal systems has proven that by conducting small pilot studies, the results of model simulations can be used with more confidence. The following are some simple tests which should be considered for calibrating PETWIN™.

Aeration batch tests. This test involves mixing a sample volume of mixed liquor from the biological treatment plant with a sample volume of influent. The mixture is constantly stirred and aerated. Samples are taken from the mixture over an appropriate period of time and analysed for components such as COD, TKN, OUR. This data provides information for determinWATER JANUARY/FEBRUARY 1997

27

WASTEWATER ing the rate constants of the system being evaluated, by monitoring the dynamic response of the sludge to an influent stream. If a treatment plant receives more than one influent stream, then this should be repeated for the different streams.

Monitoring the TKN changes assists in calculating the nitrification rate of the system. This parameter is very sensitive to the nature of the influent and can easily be inhibited, as is well known in the treatment of municipal wastewaters.

In industrial systems it is especially true, since the likelihood of having inhibitory substances in the wastewater is very high. To ensure that the desired eilluent nitrogen concentrations arc met, it is important that the nitrification rate of the actual system is quantified so model simulations will reflect the true response of the system.

Dettitrification tests. These tests are similar to the aeration batch and involve mixing influent and sludge. Instead of aerating the system, however, a source of nitrate is added to the system and the reduction of nitrate monitored over time. This assists in determining the denitrification rate of the particular system. The tests only need to be performed if denitrification is of concern in the system under evaluation.

Volatilisation tests. These batch tests involve taking a sample of influent and monitoring the stripping rate of organic material from the system. The volatilisation rate in a system is very dependent on the nature of the components being stripped.

Having designed and conducted the pilot study to meet the needs of the particular study, the data which is collected is used to quantify rate constants and subsequently, to calibrate the model. An example of using a batch test to calibrate PETWIN™ is illustrated in Figure 5. By going through this procedure, the model simulations are much more likely to predict the actual response of the system. At this stage in the procedure, the model is ready for the user to test different operating conditions and configurations to identify the best approach to operating the petroleum wastewater treatment system.

The discussions above have focused on analysis of an existing system for optimisation or retrofitting.

If PETWIN™ is being used for design of a new facility, then similar approaches are used, but with slight modifications.

If the refinery is upgrading from a lagoon system to an activated sludge system, then sludge from the lagoon can be used for the pilot studies. However, if no treatment is being done, then sludge from a municipal system or other industrial system can be acclimatised to the petroleum wastewater and then used 28

WATER JANUARY/FEBRUARY 1997

for the pilot studies. As the sludge is given time to acclimatise, the organisms required to degrade the petroleum wastewaters will start to dominate. The batch tests will then provide some direction on the type of response to expect in the wastewater treatment system.

Data Reporting

•1---,-.-----~it---ll..........~

tiF!.~1

Figure 4 An example of an activated sludge plant treating petrochemical wastewaters. This schematic representation was generated in PETWIN'M

PETWIN™ provides two forms of data for S1ream 2: Februory 25,1993 reporting system response.

2S • :i 20 A number of data files are . • Experimental I available on screen which !' 15 I-simulation summarise information on gj 10 0 •• the behaviour of the system. This includes flow •• mo rates and concentrations of so '"" T!me(mln) different compounds associated with each Figure 5 An example simulating the behaviour of process unit. Custom data a batch test for comparison with the experimental sheets can also be generresponse ated to suit the specific needs of the user.

Secondly, if a dynamic response is evaluation is to determine if the being simulated by PETWIN™, the suspended solids in the effiuent from user can monitor the changing parame- the lagoon could be reduced by putting ters by linking the PETWIN™ model them in a settling pond after the aerated to a graphical package called GRAPHER™, lagoon. As is often the case, only limited which displays the changing conditions data was available on the actual lagoon in the wastewater treatment system as it and the effluent concentrations of is happening. An example of a graphical different components. Even with output available is illustrated in Figure limited data, model simulations were 6. It presents the response of the oxygen able to produce useful results. concentration in the system reactors The influent to the lagoon was the illustrated in Figure 4 for a particular set following: of influent conditions. influent COD =60 mg/L The different forms of data generated influent TKN =17 mg/L

by PETWIN™ enable the user to influent ammonia =16 mg/L analyse various aspects of the treatment influent phosphorus =3 mg/L system's behaviour. However, it is influent suspended solids =49 mg/L important to remember that PETWIN™ flow rate =1150 m 3 per day. is a modelling tool, and that the experiThree operating scenarios were to be ence of personnel on the facility is a very evaluated: valuable asset. Models assist in pointing • current operating scheme: aerated designers, engineers and operators in lagoon with SRT=S.9 days the right direction, but experience must • option 1: aerated lagoon with a also be included when analysing results. settling basin and an SRT=25 days By applying the information gained • option 2: aerated lagoon with a from running various model simulasettling basin and an SRT=S0 days. tions, the full-scale system will operate The results of the steady state model closer to optimum conditions more simulations are presented in Table 3 and rapidly. As with any biological wastewater treatment system, final tuning must illustrate the ability of PETWIN™ to always be completed on the full-scale predict the suspended solids concentrafacility, and PETWIN™ supports this tion in the effiuent for these systems. process by providing additional The default model parameters were used for these model simulations since modelling feedback. only an estimate of system performance was required. The actual suspended Example 1-A Lagoon A simple apphcat1on of using solids concentration in the system was PETWIN™ to predict the response of a 130 mg/L compared with the model biologtcal system treating petroleum prediction of 138 mg/L. The accuracy of the model predicrefinery wastewater, is to run steady state simulations on an aerated lagoon tions on the existing system provides system. In this example, the aim of the some assurance that the model predictions of alternative operating modes wi11

"~---------------,

"

-

""

WASTEWATER the effluent quality. waters could be quickly selected.

Analysis of two potential configurations produces Conclusion two ve1y different effiuent In summary, PE TWIN™ is a tool to qualities, as presented in assist designers and operators of the Table 4. Both systems biological wastewater treatment plants were simulated with a operating at petroleum and petrochemsludge retention time of ical refineries in understanding the !

38 days. '""+-. ----behaviour of the system. It provides an .. 'The first configuration effective way of analysing many differsimulated was simply a set ent operating scenarios in the initial of four activated sludge design or evaluation stages, so that tanks in series, with the better decisions can be made in the first tank receiving all design and operation of the wastewater Figure 6 An example of the graphical output influent streams. As the available from GRAPHERTM. This graph monitored results in Table 4 indicate, treatment facility. The result is often the change in oxygen concentration for the system this configuration resulted significant cost savings.

If only approximate system response illustrated in Figure 4 in a large concentration of soluble COD being is required, then default parameters can discharged from the be used. It becomes even more effective activated sludge system. when it is possible to characterise the This was due to the fact influent wastewater and calibrate that some very highly PETWIN™ to the system of interest by conce.ri:tratea' influent performing some simple batch tests. streams were being mixed Any major decisions for large plants Iii Iii with high flow streams. should only be made using model The result was a short simulations in a properly calibrated hydraulic residence time model.

(HRT) for components which required long Acknowledgements HRTs. Long HRTs arc The PETWlN™ model developFigure 7 Option 2 configuration for the petrooften required in ment project was funded by Imperial chemical wastewater treatment plant petroleum/petrochemical Oil as part of the activities of the treatment plants to ensure Imperial Oil/Wastewater Technology sufficient contact with the Centre Industrial Chair in Environbe reasonable for the level of accuracy required. If greater confidence was microorganisms because the pollutants mental Systems Engineering at required, a more extensive validation are soluble in nature.

McMaster University at Hamilton, A second process configuration was Ontario, Canada. Thanks also to those procedure would be nccessa1y. simulated on PETWIN™, as illustrated industries who provided guidance and in Figure 7. Option 2 addressed the Example 2-Activated Sludge real data for the development and appliissue of extending the HRT for influent The following example illustrates the streams with highly concentrated, cation of PETWIN™. use of PETWIN™ to simulate two slowly degradable compounds. The low different wastewater treatment plant flow, high concentration inputs were References configurations designed to treat directed to the first tank in the series, Baker A J, Dold PL (1992) Activated Sludge Treatment of Petroleum Refinery wastewater generated in a petrochemi- The other two high flow, less concenWastewater: Part 1-Experimental cal facility. The facility generates six trated streams were directed to the Behaviour. l Vat. Sci. Tech., 26, No. 1-2. different waste streams which must be second tank in the series where they Baker A J et al. (1994) 'Development of a treated before discharge. Each stream were mixed with the discharge from the Dynamic Mechanistic Model for Activated contains very different contaminants first tank. This configuration improved Sludge Treatment of Petrochemical Industry Wastewater,' presented at the and in varying concentrations. Some of the eilluent soluble COD concentration Canadian Water Pollution Control the streams are continuous flows, while from 1278 mg/L (Option 1) down to Conference, Wastewater Technology others arc intermittent. Without a 312 mg/L and the soluble TKN Centre, Burlington, Canada, February. computer simulation tool of the system, concentration from 35.6 mg/L down to Jones RM, Dold P L, Baker A J, Briggs TA it would be ve1y difficult to predict the 0. 9 mg/L. These are significant (1994) Simulation for Optimisation of a impact of these different streams on the improvements in eilluent quality simply Biological Treatment Process at a Petrochemical Plant. Presented at the 49th final effluent quality, and therefore by changing the flow patterns around Annual Industrial Wastewater Conference, make decisions on the optimum operat- the system.

Purdue University, Indiana, USA. ing mode. When designing a system to Further manipulation of the configutreat such wastes, the tendency is to rations would be required to ensure that Author over design the plant to ensure the the desired effluent quality is achieved, Dr Alison Baker is a chemical e11gi11eer wastewater is treated properly. This is a but simulation of these two configuracostly approach. However, with a tions illustrates the type of information who gained her PhD i11 E1wfrolll11ental simulation tool, different methods of that can be collected by applying the E11gi11eel'ing from lvlc1Vfaster U11h1ersity, treating the wastewaters can be tested to PETWIN™ model. If the example Ontario Ca11ada in 1994. She joined sdtct lhe best <lesign or lo re-evaluale abuvt was a rdruGt slu<ly, Lht:11 an exisl- CA1PS&F E11vir011111cntlll in 1995, mid has the operation of the system and seek ing wastewater treatment plant could be bee11 worki11g in e11viro11111e11tal 111a11ageme11t better operating modes. retrofitted quite readily. If the system and auditing, and eval11ati11g and optimising Preliminary simulations with these was a new design, then the most wastewater treatmrnt systems, applying petrochemical wastewaters indicate the economical configuration or range of PETWJNTM and BIOWJNnt where impact that process configuration has on options required to treat the waste- appropriate.

OXYOEN UTIUS,.TIOH RESPONSE m THE SYSTEM REACTORS Im~)

I

Ill

1

WATER JANUARY/FEBRUARY 1997

29

WASTEWATER

RECYCLING OF RECLAIMED WATER IN SOUTH AUSTRALIA NM Kayaalp

(WWTPs) of the SA Water Corporation (SA Water), was for limited agricultural and golf course irrigation.

Abstract As the focus shifted, firstly the This paper reviews the recycling of discharges from two of the SA Water reclaimed water in South Australia (SA) WWTPs along the River Murray were our driest state. It concentrates on small stopped altogether, with the aim of -scale schemes in 'unsewered areas', ie reducing nutrient discharges to the in areas that are not serviced by the SA river. Reuse included a golf course Water Corporation's sewerage schemes. irrigation for 3 000 equivalent populaIt demonstrates a growing trend as tion (EP) at Mann um WWTP, and public perceptions shift. creation of wetlands and the irrigation of army land for 12 000 EP at Murray Keywords Bridge WWTP. Reclaimed water, irrigation, dual A more recent application was reticulation, septic tank effluent reclaimed water recycling from a 600 disposal EP plant at Gumeracha (a small township close to metropolitan Introduction Adelaide on the River Torrens) which The terminology in the wastewater feeds two water supply reservoirs field started to change in the 1980s, downstream. Discharge to the river together with changes in the perception from this plant ceased in exchange for of 'waste' versus 'resource'. We no reuse at a nearby pine plantation, longer talk about 'effluent' but owned and operated by the Department 'reclaimed water', not 'sludge' but of Primary Industries. 'biosolids'. The idea of 'disposal' of It seems there are several other wastewater effluent shifted to schemes in the 'pipeline' for reclaimed 'recycling' or 're-use'. This shift in water reuse from various SA Water terminology has occurred not only in WWTPs and proposed build, own and the language of authorities but in the operate (BOO) plants. Of course the public perception. It seems that every- biggest water reuse proposal in SA is the body is interested in one type or Bolivar scheme. Bolivar WWTP is the another treatment and reuse scheme, largest wastewater treatment facility in whether it be for reclaimed water, SA. It is proposed to reuse at least half stormwater or biosolids. of the 50 000 ML/year reclaimed water The world wide trend of moving produced by this plant for the horticulfrom centralised systems to localised tural area in northern Adelaide. systems (Tchobanoglous, 1996) is Currently, ground water is used extenalready occurring in South Australia far sively, causing ground water pressure more than is usually recognised. decline and salinity intrusion problems.

Having dealt with the approvals of Such a scheme will have the additional localised wastewater schemes by work, benefits of reusing a resource-the an article has been published by this reclaimed water-and reducing nutriauthor on the regulatory framework, ent discharges to the marine environoptions and possibilities for reclaimed ment, thus limiting man-made adverse water reuse in SA (Kayaalp, 1996.) effects on sea grasses near the discharge In this article, however, it is the location (CMPS&F, 1993). extent of reclaimed water reuse applicaHowever, the reuse of reclaimed tions-including small scale systems in water does not stop at SA Water reuse SA-that is covered. The emphasis is schemes. The trend is for an extended on reclaimed water reuse in 'unsew- scale and acceleration even outside the ered' areas (the areas that are not SA Water sewered areas. Whether it be serviced by the SA Water Corporation's smaller capacity plants, a country town sewerage systems), because although a scheme, a private development or an number of them exist at various capaci- individual house application, an importies, they receive very little mention. tant 'shift' has occurred in SA's approach to reuse reclaimed water. It Sewered Areas seems that the reuse of reclaimed water Initially, reuse of reclaimed water has become part of the community from the wastewater treatment plants psyche.

30

WATER JANUARY/FEBRUARY 1997

Unsewered Areas The types of reuse schemes in 'unsewered' areas, that is, the areas not serviced by the SA Water sewerage systems, are summarised in the following sections.

Under the Public and Environmental Health Act-Waste Control Regulations 1995 (previously under the Health Act) the SA Health Commission (SAHC) is the approving authority for any wastewater collection, treatment and disposal schemes in areas that are not serviced by the SA Water sewerage schemes. Also, any reclaimed water reuse scheme requires SAHC approval. The South Australian EPA licenses on going discharges and reclaimed water reuse.

On-site systems. In 1989, the SAHC produced its first guidelines on on-site secondary treatment and disposal, covering sand filters and reuse of reclaimed water for irrigation within the allotment. In these guidelines it was stipulated that reclaimed water be used in a dedicated area with minimum human contact, preferably for the irrigation of native species. The minimum area required for an average household is 200 m 2 .

In 1990, guidelines for on-site treatment and disposal using aerobic units (with similar conditions) followed. This was a great step forward from allowing septic tanks and subsurface soakage systems only. The obvious benefits of such a reuse, though it may be on a relatively small scale, are: • recycling a resource • minimising possible adverse effects on the environment and on the public health • the aesthetics of greening the areas.

Today, throughout SA, there are more than 3000 aerobic treatment units and sand filters installed on-site for individual houses or for wastewater of domestic nature from commercial premises. This is about 20 % of overall on-site installations in the past five to six years. The ratio of sand filter installations to aerobic unit installations is also increasing as the sand filters are seen to be a 'more natural-greener' process by more and more people.

Since May 1995, the administration of on-site systems has come under the jurisdiction of local councils.

WASTEWATER STED Schemes The septic tank effluent disposal (STED) schemes so popular in SA country townships, started with the installation of a scheme at Pinnaroo in 1962. Effluent is collected by common drains from the septic tanks in an area or

township and treated locally. The treatment used to be by oxidation and stabilisation lagoons, with the secondary effluent being discharged to nearby creeks or to evaporation lagoons or pans as they were usually called. In some cases, the common effluent was

Table 1 Reclaimed water reuse from various town STED lagoon systems Location

Reuse purpose

EP

Birdwood-Gumeracha Berri Barmera

950 6,000 4,300 3,100 800 600 400 600 2 000 1500 500 6000 1,100 800 1,200 800 3,500 800 2,600 1250 2500 5,000

Clare Cleve

Cummins

Echunga Eudanda

Kadina Kingscote Lameroo Loxton Lyndoch

Meningie

Penola Pinarroo Goolwa Robe

Strathalbyn Streaky Bay

Tanunda

Willunga-Mclaren Vale Total

Irrigation of oval Irrigation of race course Tree irrigation Mixed with gw-golf course irrigation Irrigation of oval Mixed with sw-local reuse Mixed with sw-golf course irrigation Local reuse Irrigation of playing fields Golf course irrigation Mixed with sw-golf course irrigation Mixed with fruit juice waste-woodlot irrigation Vineyard irrigation Irrigation of golf course Irrigation of 33 ha grass land Mixed with sw golf course Irrigation of woodlot Irrigation of sand dunes Equestrian and polo fields irrigation Irrigation of ovals and green areas in the town Vineyard irrigation Wetlands + irrigation of golf course

46,300

Source: Local Government Association Records, SA Health Commission approvals

Table 2 Reclaimed water reuse from compact wastewater treatment plants Location

Reuse purpose

EP

1,000 3,000 1,000 300 4,200 6,500 500 500 17,000

Black Point Coober Pedy Maitland Mt Compass Normanville-Yankalilla Renmarl< Roseworthy Southend Total

Tree plantation Irrigation of school oval Recreational areas Golf course irrigation Golf course irrigation Irrigation of ovals and green areas in the town Irrigation of ovals Irrigation of dedicated areas

Source: SA Health Commission approvals

\

•ADELAIDE ·c1eland

FLEURIEU PENINSULA

Goober Pedy

• Echunga • Mclaren Vale

•willunga

Normanville

•Yankalilla Wirrina

) GREAT AUSTRALIAN BIGHT

Note: 1. Reuse schemes arc indicated in dots ( •)

EYRE PENINSULA

Clare

Kadina

.

Pomt

Eudunda ~enm~r1< • Bannera• Ben

Maitta~

1 , Roseworth~ .Tanunda Pearce 4 ) •. Lyndoch Black • 81rdwood Y O R K ~Point Osborne

PENINSU

SOUTH A U S T R A L I A

•

ADELAl;E .)

(see ,n,e/t)-=

Loxton

discharged to SA Water (then EWS) sewerage systems without further treatment. According to a SAHC report on the history of septic tank effluent disposal schemes (revised in June 1992), there were 962 km of STED drains in 88 townships.

Only a small percentage of the early STED schemes involved reclaimed water reuse. In some schemes, use was achieved by mixing the effluent with stormwater or groundwater. Certain schemes did not have any reuse systems but incorporated them later. In other cases, existing reuse systems were extended.

The STEDs serving various towns that have lagoon systems for treatment and incorporate reclaimed water reuse are shown in Table 1.

Most of these systems were installed in the late 1960s and 1970s. One of the more recent of these reuse schemes at Tanunda started about 15 years ago with a mutual agreement between the winery growers in the area, whereas the Robe system was installed in 1987. Reclaimed water reuse from Streaky Bay (commissioned in 1992), Willunga and Lyndoch (both commissioned in 1995) are even more recent.

At some townships, as the population the lagoons became increased over-loaded with increased flows.

Consequently, the practice of discharging secondary efiluent to water courses became less and less acceptable by legislation and by perception. The recent trend is towards upgrading some of the existing STEDs treatment systems by replacing the lagoons with more compact treatment plants providing secondary or further treatment with reclaimed water reuse. Reuse schemes with compact WWTPs are summarised in Table 2.

At Renmark, a 6500 EP package treatment plant has replaced the existing STED lagoons which are to be used for emergency overflows only. All the efiluent is to be used for irrigating sport grounds in the town, the high school oval, the main road median strip and the greening of the old railway land.

Coober Pedy's system, built in 1994, reuses reclaimed water to irrigate a school oval with a subsurface irrigation system. At Black Point, Central Yorke Peninsula, 220 holiday homes are to be connected to the system. About six ha of land with sandy soils, 200 metres from the coast, is to be planted progressively with about 10 000 trees. There are several other schemes under construction or at the commissioning stage, like SouthenJ, Roseworthy and Normanville-Yankalilla STED schemes.

Other Applications Dual reticulation. In 1995-for the first time in SA-a communal, sewage-

WATER JANUARY/FEBRUARY 1997

31

WASTEWATER reclaimed water scheme was designed.

The scheme was designed for reuse in domestic gardens and toilet flushing at the New Haven development in Osborne for 65 residences, with 165 EP. This was a MFP (multi function polis) initiative arranged through the SA Housing Trust as an advanced technology residential development. As well as this new approach to wastewater reuse using a non-traditional disinfection (a UV system), other initiatives like geothermal heating were also implemented. First flush storm water collected in an underground storm water tank is also treated in the WWTP. For toilet flushing and garden watering, a secondary reticulation carries reclaimed water to the houses in 'lilac' colored pipes. Reclaimed water is also used for sports field irrigation by means of a subsurface system.

The trend is growing in many sectors of the community-including private developments, Aboriginal settlements, freeholding shack sites and individuals with a 'green' perspective.

Private developments. Reclaimed water reuse is also becoming popular in tourist developments, such as Lake Side Holiday Park, McLaren Vale, with an 800 EP system and woodlots irrigation; or at Wirrina, where wastewater from an existing resort and new extensions of condominium and condotel units serve about 1700 persons. At Wirrina, the existing lagoons have been decommissioned. Ornamental ponds, used as the winter storage of reclaimed water, are at times topped up with stormwater.

Reuse is for the golf course irrigation at the development site. More recently, a system has been put in at Leonard's Mill Motel complex at Second Valley. This 100 EP system will serve the existing motel and its extensions and the reuse is for native trees irrigation.

Aboriginal settlements. Camp Coorong near Meningie (100 EP), Yaralina Aboriginal Community at Ceduna (130 EP), and Point Pearce Aboriginal Community (100 EP) wastewater systems include reclaimed water reuse for irrigation of surrounding areas that arc operated by the local Aboriginal communities.

Shacks. The SA Health Commission is receiving numerous applications for wastewater treatment and reuse systems for shacks on Crown land as a result of the government policy on freeholding.

At this stage, wastewater treatment and reuse schemes only exist as concept plans. However, most of the shack owners showed interest in freeholding.

Considering that there are about 150 shack areas along the River Murray and the coastal areas, with 1600 shacks to freehold (Shack Site Freeholding Committee Report, 1994), in a few years time there will be a considerable 32

WATER JANUARY/FEBRUARY 1997

number of reclaimed water reuse Table 3 EP of current reclaimed schemes of various sizes coming on line. water reuse in unsewered areas of Others. Several golf courses and SA-1996 other recreational facilities also reuse System Reuse as EP their reclaimed water for irrigation.

3 000 onsite systems 9,000* Some of these have considerable STEDs Lagoon Systems 46,300 amounts of reclaimed water production -from Table 1 and reuse. For example, Cleland Park STEDs compact WWTPs 17,000 (operated by the Department of -from Table 2 Environment and Natural Resources) Other Applications has a 400 EP system and reclaimed Dual reticulation 165 water use for irrigation of the trees in Private development 2,600 the park. Blackwood golf course and a Aboriginal settlements 330 Others 600 driving range at O'Halloran Hill have 100 EP plants each and reuse the Total 75,995 reclaimed water for irrigation within the Note: The term 'unsewered areas' indicates development. the areas that are not serviced by the SA It is also worth mentioning that the Water Corporation's sewerage systems. interest in the use of waterless toilets and greywater reuse systems is increas- environmental issues like the algal ing. Some people, even in sewered blooms that started to occur so often in areas, are getting exemptions from the the narrow and shallow waterways, SA Water Authority to disconnect from makes the case even stronger for reuse the sewerage system and reuse grey- of reclaimed water. water. A couple of these systems are At present, in unsewered areas of SA, using grcywater for toilet flushing after recycling of reclaimed water is about treatment. In unsewered areas, several 30%, consisting of numerous schemes composting toilets have been installed, of various sizes. If we include the although so far the numbers for grey sewered areas, recycling of wastewater water reuse applications are still low. equates to about 13%. The interest in reuse is mainly in irrigation of municiSummary pal ovals, parks and golf courses. There The number of reclaimed water is also a growing interest in the winery reuse scheme locations in unsewered and orchard industries in the use of areas of SA are summarised in Table 3 as reclaimed water of domestic origin from equivalent population, which indicates any source for irrigation. the number of people whose wastewater Looking at the existing number of is recycled. schemes outside metropolitan Adelaide, As can be seen in Table 3, the reuse the number of submissions, inquiries schemes equate to about 76 000 popula- and interest coming from all sectors of tion in unsewered areas. This means an the community, it is not difficult to estimated 30% of SA households and 'guesstimate' that more and more developments are recycling out of the reclaimed water reuse applications will total population of 1 450 000 in SA; and follow in and outside Adelaide and in about 1 200 000 people are serviced by countiy areas. For Australians, it is no the SA Water sewerage systems (SA longer a concept but an increasingly Water Report 1995; SA Water popular practice.

Technical Practices data).

If current reclaimed water reuse of References about 15 000 EP from the three SA Camp Scott Furphy Pty Ltd. Report on Strategics for Water WWTPs mentioned in Section 2 the Future Operation of the Bolivar Wastewater Treatment Plant (1993). above and the estimated current reuse from the metropolitan WWTPs of Kayaalp NM (1996). 'Regulatory Framework in South Australia and Reclaimed Water Reuse Options about 100 000 EP (based on the populaand Possibilities', International Journal on tion connection and percentage reuse Desalination and Water Reuse, v106, pp 317-322. data, (reuse from Bolivar 10%; from Local Government Association of South Australia Records on Septic Tank Drainage (STED) Glenelg 16%; from Christies Beach Schemes.

5%-estimated) are also included, the Shack Site Freeholding Committee of South Australia Report on Freeholding of Shack Sites on Crown reuse schemes overall will equate to Land (1994). about 190 000 population's wastewater, South Australian Health Commission Records on about 13% recycling throughout SA. Septic Tank Drainage (STED) Schemes.

Conclusion It is clear that in conjunction with the changes in the legislation, guidelines and requirements, the trend in reusing reclaimed water is growing. In the driest state of the driest continent, it appears to be widely accepted that a precious resource-water, in any form-must be recycled. This notion, combined with

South Australian Health Commission Records on Approvals Given to WWTP and Reclaimed Water Reuse Schemes.

South Australian Water Corporation Report on Adelaide Wastewater Treatment Plants Environment Improvement Programs (1995).

South Australian Water Corporation-EWS Technical Practices Data on the Sewerage Systems.

Tchobanoglous G (1996). 'Appropriate Technologies', a paper presented at the WaterTcch Conference, 27-28 May 1996, Sydney, Australia.

WASTEWATER

Anaerobic Processes The subject of the Victorian Industrial and Hazardous Wastes special interest group seminar, held on 21 May 1996, was 'Anaerobic Processes'. Three speakers made presentations on different types of anaerobic systems: high rate UASB low rate bulk volume fermenter fixed film.

The meeting was chaired by Peter Draayers, Regional Manager KME, and attended by around 55 people who represented a large cross-section of industries and water authorities.

Dr Brace Boyden, Business Development Manager of Aquatec Maxcom, made the first presentation: 'Anaerobic Technologies From Paqucs BV'.

Aqua tee Maxcon is the Australian-New Zealand licensee for Paques, a major supplier of high-rate anaerobic technology around the world. Brace introduced the various technologies available from Paqucs then described the UASB technology in more detail. He pointed out the following advantages UASB has over aerobic treatment: • much lower power consumption (net energy producer in the form ofbiogas) smaller land requirement lower sludge production • lower nutrient consumption can be shut down for long or short periods.

However, it has a few disadvantages-it requires caustic for pH correction, does not produce secondary quality cffiucnt and has lower resistance to toxic shocks. UASB is well suited to treating waste waters from breweries, wineries, distilleries, soft drink factories, food processors, dairies, pulp and paper manufacturers, and pharmaceutical industries.

The next speaker was Don McRae, Senior Consultant, KME, whose presentation was on 'Treating High Strength Wastewater Using the Bulk Volume Fermenter'. KME is the Australian licensee for Canadian company ADrs patented Bulk Volume Fermenter (BVF®) digestor. The BVF® is a low-rate anaerobic treatment utilising larger reactor volumes than UASB and other high-rate systems. It is well suited to the rural food processing and dairy industries where land is not at a premium. Don pointed out that where land is not expensive, the BVF® technology has the following advantages over high-rate systems: • lower construction costs due to less expensive earthen construction and/or simpler system

mechanism is being developed to manage wastewater reuse. The guidelines encourage the adoption of best practice environmental management, focusing on objectives and outcomes rather than the previous prescriptive regulations.

The performance-based approach of the guidelines will replace the current need for any licensing or permit under the Environment Protection Act or Health (Use ofWastewater) Regulations for a reuse scheme.

Environmentally aware people seeking a better environment or competitive advantage, should find merit in this approach. Best practice environmental management or wastewater reuse will achieve benefits for the community in terms of sustainable· improvements in environment quality.

In general, the guidelines will cover the following areas: • Potential Reuse Options-identifying potential uses of treated wastewater for residential, industry or agricultural purposes • Roles and Responsibilities-defining the roles and responsibilities of suppliers and users of wastewater Quality-specifies • Wastewater quality limits for intended uses • Wastewater Treatment-specifies level of treatment required for particular uses • Site and System Control-characteristics of site and selection of land for wastewater reuse considering amenity, plumbing, contingency plans, operations and maintenance • Performance Monitoring-measures to be taken to demonstrate that the wastewater is suitable for the intended use and Notification• Reporting provides for consultation and 1Totification of activities to agencies and the Report by Mohit Sibal community about wastewater.

These guidelines will be reviewed regularly and updated as necessary, on the basis of operating experience and the development of national standards.

On 12 March, 1996 there was a joint The second speaker was Roger meeting of the Victorian branch's Wrigley. Roger is a Senior Lecturer at Wastewater Treatment Special Interest the University of Melbourne (Faculty of Group and the newly formed Society of Agriculture, Forest1y and Horticulture), Environment Engineering. The meeting based at Dookie College. Roger's was attended by over 60 participants. presentation focused on the relationship John Lawrey, EPA Victoria, started between the source of wastewater and the session with an overview of the long the influence of physical, chemical and awaited Guidelines for Wastewater Reuse. biological characteristics on treatment, John commented that the EPA is storage and ultimate reuse. seeking to improve the ways in which The scenario for elevated water its responsibility for protecting the tables, dryland and irrigation salting and environment is managed. the increased water pricing will require As the water industry has become the development ofintegrated strategies. more responsive and committed to In the past, end-of pipe solutions environmental outcomes, an alternative have meant that engineers handed • better process stability due to long HRT and large biomass inventory • lower requirements for pH control chemicals • lower sludge disposal costs due to very long sludge retention times within the reactor.

The BVF® also has a disadvantagelike most anaerobic systems-in that it docs not produce secondary quality effiuent.

The design COD loading to a BVF® digester is in the range of 0.5-3 kg of COD/m 3 day, as against 10 kg of COD/m3 day for high-rate systems and 1 kg of COD/m3 day for aerobic systems. Don also presented a case study on the BVF® plant at Allansford, which treats 2 ML/d of high strength (over 30,000 mg/L COD) dairy waste waters and achieves over 95% BOD and COD removal efficiencies.

The final speaker was Grant Corrin, Director of Leyton House Industries, who spoke on 'Fixed Film Method for Anaerobic Digestion'. Grant began with an overview of the four stage process of anaerobic decomposition and its applications, before introducing the fixed film biological process. Leyton House Industries manufactures Bio-Block™, a plastic media used in fixed film processes. This media has the following features: • provides high specific surface area (100-300 m 2/m3) • lower density than traditional stone, gravel and pottery high voidage to eliminate clogging • ordered/channelled design.

Grant highlighted some of the salient features of fixed film processes: • low tech, dependable and smaller space requirements low capital and operating costs high biomass density and production case of altering HRT.

Wastewater Reuse

WATER JANUARY/FEBRUARY 1997

33.

WASTEWATER responsibility for disposal to agriculture scientists and farm management consultants. This has lead to some problems with lack of communication and a failure to acknowledge the influence of treatment and storage on the sustainability of disposal sites.

The concept of closed systems and mass balances for sustainable land use can contribute to the lack of recognition that there must be an export of nutrient and salt from a wastewater reuse site.

Nutrients are usually best exported in agricultural or forestry enterprises, while salts need to be removed from the root zone by leaching action, with salt export to soil, groundwater or surface waters.

Sustainable wastewater irrigation practice dictates that salt needs to be leached from the root zone of the plant species grown. Export of salt from a site is critical. In addition, to counter the adverse influence of sodium on soil structure (leading to a diminution in infiltration rate) gypsum needs to be applied.

Gypsum serves as a source of calcium ions while increasing soil electrolyte concentration (which leads to a 'flocculated' soil structure). Gypsum application in the absence of enhanced soil drainage will have limited utility.

Salts leached from a plant root zone need to be exported to the soil profile, groundwater, surface water, evaporation basin. These salts are not all NaCl. In the past, many wastewater irrigation systems were designed to facilitate salt export to soil profiles below the plant root zone. Elevated water tables and groundwater mounding can readily mobilise this salt. In addition, export to groundwater can limit the beneficial uses of this resource.

Enhanced drainage and the disposal/reuse of collected tailwater should be vital components of any wastewater irrigation project.

The final speaker was Bernard Clancy, a project manager with Montgomery Watson Australia Pty Ltd. He spoke about a recent study completed for Sydney Water, which assessed the feasibility of decentralising the treatment and reuse of wastewater from new growth areas in the Hawkesbury-Nepean catchment.

The scope of the study allowed for the development of wastewater treatment and reuse options applicable to single households and up to a community of 10,000 people. Greywater treatment and reuse were addressed as major components of the study. One of the major aims of pursuing these types of sewerage schemes is to give the individual household or community ownership of the wastes and the responsibility for sustainable disposal.

34

WATER JANUARY/FEBRUARY 1997

Of the major findings, the area required for the sustainable reuse of effiuent from the schemes was the most significant. The development densities which would sustain decentralised wastewater schemes, providing reuse of dry weather flows, were generally much lower than those typically proceeding in urban developments today. Maximum densities of nine lots per hectare were typical for decentralised wastewater strategies. This finding has a significant impact on the cost of the development, the returns available from it and the provision of basic infrastructure such as roads and transport, and water supply.

On-site treatment systems for individual households were generally considered less reliable, more expensive and created higher health risks than community based systems. Regulation monitoring and maintenance were also raised as issues which would need to be specifically addressed with a large scale application of these schemes.

Report By Poll Wong

NSW Conference The NSW branch's 1996 regional conference, held in Queanbeyan from 6 to 8 September, had some 160 attendees including spouses and children. Mayor Frank Pangallo, Queanbeyan City Council, opened the conference.

Dimce Miliailovski, Kilpatrick Green.

The successful tenderer for this job was Kilpatrick Green, with SKM for process design.

Reason for design, develop, construct approach: • perceived to be tremendous advances in se,vage treatment technology pressure from suppliers • believed to be reduced risk for client • clearer identification of outcomesperformance based specification.

Kilpatrick Green spent some 40 man weeks in bidding (20 to 30 engineers and draughtsmen). If the other bidders spent something similar, then a total of 200 man weeks would be spent-with approximately 80% being thrown out at the end. The process involved chemical P removal with activated sludge treatment. There was considered to be no significant scope for new technology.'

During discussion at the end, John Anderson (Department of Public Works and Services) stated that Public Works is looking to suspend future design and construct projects (and is considering a general reduction to three tenderers).

Monitoring the impact of Bulahdelah sewage treatment plant effluent-the use of ecological surveys. Leela Caiger, Robyn Tuft &

Associates, talked about how ecological surveys are used in conjunction with physical and chemical data to assess the health of waterways. Biological data Saturday Technical Seminars reflects the average condition over time.

Management of water supply & She presented an example of a recent sewerage services In country NSW. study carried out at Bulahdelah (NSW Johtt Moorhouse, Department of Land mid North Coast). The creek is subject and Water Conservation talked about to agricultural and STP inputs. The how the Urban Water Directorate of STP effiuent improves DO, although DLWC administers the Country the recent introduction of chem P Towns Water, Sewerage and Drainage removal lead to three fold increases in Program. This provides technical and TDS in the creek.

Low cost sewage treatment works financial assistance to councils.

Financial assistance may be provided up with simple operation/reuse. The to 50% (investigation studies and capital presenters were Roger Pettitt, Rust works). There were still some PPK and Geo.ff Porter, Orange City challenges, as about 300 small towns Council. Roger spoke about Spring Hill and villages still have septic tanks. John Sewage Treatment Works (1000 EP). It also spoke about benchmarking council is an extended aeration plant-involving low cost idea with single aeration operations and effiuent re-use policies.

Water pricing in Queanbeyan. Bill lagoon (intermittently aerated, continuSivan, Queanbeyan City Council, ously decanted, with baffie at end to discussed recent moves to a user pays separate settling zone/clarifier). Sludge system. Current reuse economics put thickening is carried out by a single the price of recycled water at about precast concrete tank, with tankering off site. Effiuent reuse is applied to $0.70/kL (potable $0.25/kL).

Molecular orientation of PVC pipes. adjacent nursery after maturation Peter Chapman, Vinidex Tubemakers, ponding and storage.

Reuse of water treatment plant focussed on the benefits of the treatment enhancement of PVC pipe and its alum sludges In wastewater treatment mechanical properties. The pipes also plant. David Tolmie, Centre for Wastewater Treatment, University of involve lower costs.

Cooma STP-dellvery of project NSW, talked about the significant using design, develop, construct quantities of water treatment plant approach. The presenters were David sludges which contain alum. They are Byrne, Cooma Monaro Council and difficult to dewater and characteristics

WASTEWATER are very site specific. Trials have been carried out at Bowral Sewage Treatment Plant, involving extraction of aluminium by caustic soda, which is subsequently dosed to the STW process for chemical P removal. An economic model has been developed by the university to determine the feasibility of this process for councils-incorporating quantities of sludge, dosing requirements at STW, land disposal costs, transport costs, savings in lime etc.

Women in the water Industry. The aim of the new interest group is to foster the role of women in the industry, but it was noted that co-mingling is required for the group to be successful.

Biosolids management in country NSW. Lisa Ratvlinsott, LV Rawlinson &

Associates, spoke about managing sludge in country NSW and what was meant by the 'sludge guidelines' (currently under review and due for imminent re-release). Landfill versus reuse will depend on economics and community expectations, landfill capacity and others. Lisa saw that possibly the cheapest way of disposal for country councils was for urban landscaping and golf course application. Agricultural application would be better suited for larger STW. For any reuse project, a good community consultation program needs to be implemented.

The EPA's compliance audit program. The presenters were Colin

Storey and Maurice Pignatelli from the EPA. Colin described the program in relation to auditing of STW. The audit basically involved an unannounced site visit and chatting to operators about the objectives of the audit and the existing plant licence (the subject of the audit and how its conditions are currently being met). After the audit (which goes over monitoring and analytical work carried out and other conditions contained in the licence) there is a verbal briefing given about the auditor's findings. Subsequently, a report is provided outlining background, noncompliance-performance and an action plan.

Community expectations and a strategic focus. Cary Reynolds from

ACTEW created a stir by aiming questions at the audience and lobbing lollies to whoever gave the correct answer! He challenged engineers to reassess their role in developing strategies and their approach to community consultation, stating that the community wanted to be involved in collective partnerships in environmental develop1nent.

Forget the mass media (one way communication), you need to carry out market research. He cited several examples of this which had been carried out by ACTEW, with consequent

projects in full swing: sewer mining â&#x20AC;˘ resource efficient homes â&#x20AC;˘ composting toilets (created small suburban community) â&#x20AC;˘ electricity demand flattening.

All initiatives came from the community. He stated that utilities need to seize the initiative and make it happen. The major benefit is augmenting existing infrastructure and deferring large scale engineering projects.

but is making a significant profit. Local government must embrace business concepts.

Paul concluded by saying that water is strategic to the future of Australia.

Research centres are at the core of the future vision, and he cited the Centre for Wastewater Treatment as a good example. The Australian water industry can contribute to the global industry.

Water Industry national transition program. Vittce Ball, ACTEW, detailed

The Plant -Manager of the Lower Molonglo Water Quality Control Centre, Asoka Wijeratne, acted as our tour guide. It is a very impressive plant, considering it was constructed in 1978.

Process involves: 1. chemically assisted sedimentation using lime to maximise solids removal 2. biological nitrification and carbona-: ceous BOD removal in a cascading weir activated sludge arrangement 3. secondary clarification 4. tertiary filtration (involving DAF) 5. chlorination and dechlorination.

Sludge is incinerated, with the product ash-known as Agri Ashbeing supplied to local farms (demand exceeds supply). Phosphorous removal is to a very high degree and is based on chemical precipitation using ferrous chloride, achieving <0.08 mg/L in the final effiuent.

Although the secondary clarifiers are in definite need of a clean up (rafting sludge and weed generation), the final plant effiuent is certainly aesthetically pleasing as it cascades over a constructed whitew_?ter rock outcrop on its way to the Molonglo River.

the new training program, which involves curriculum development and competency level accreditation, environmental view points and due diligence. The program focuses on technical issues within the industry, not just generic managerial items.

The after dinner speaker was Paul Perkins, Deputy Chief Executive of ACTEW and Deputy Chairman of the Environmental Industry Association.

Paul gave a passionate speech about water professionals holding the key to the future of water resources in the country. The talk had a simple theme: people in the water industry need to regard themselves as being in a business.

Given the existing global competition, a paradigm shift is needed for public utilities to become competitive. Unless this happens, there is a risk that emerging Australian technologies will be lost in the market. Paul stated that people were prepared to pay for environmental improvement. Unless money is put into research, we cannot hope to get anywhere. We cannot achieve excellence in the environment, unless we take risks and invest. ACTEW is spending nearly $10m on R&D-all in the pursuit of markets.

There is pressure on authorities to reform the industry. It is perhaps the fault of practitioners that the water industry has not changed. We should be looking at the needs of water resources for the future. Don't accept rising salinity and subsequent irrigation problems.

At present, confidence is lacking for getting on top of potential issues. We can create markets.

In a follow-on to Cary Reynold's presentation, Paul stated that ACTEW was not doing anything unique, similar projects had been done overseas. What was unique was the way that it was being done: 1. composting toilets installed in the suburbs, not only peri-urban areas 2. sewer mining, which is not only being carried out for economics.

Some of the most exciting things are happening in the local communities. It's a case of ecologically and economically sustainable development (Agenda 21)having a go. ACTEW is a small utility,

Lower Molonglo Control Centre

Southwell Park Sewer Mining Project Here the guide was Ian Bergman, from the Department of Science and Technology. The plant, opened in 1995, is adjacent to a sports field, producing some 300 m 3/day for irrigation.

The process involves: 1. screening 2. primary sedimentation 3. biologically aerated filters for carbonaceous BOD removal and nitrification 4. followed by microfiltration and chlorination.

All process units are housed in a single building, which is air ventilated via a chemical scrubber to control odours.

There is no effluent storage, so during winter when demand is low, the effiuent is passed back to the sewer.

During summer (peak demand), effluent is supplemented with potable water for irrigation of the fields. The irrigation system is computer controlled.

WATER JANUARY/FEBRUARY 1997

35

BUSINESS

LIABILITY OF AUTHORITIES AND THEIR CONSULTANTS N Hemmings

Abstract Authorities/councils are faced with an increasing exposure to common law liability for environmental harm as a result of a willingness by the courts to expand the range of situations in which they are found to owe a duty of care.

Nevertheless, the common law is still viewed by the regulatory authorities as an unsatisfactory tool for the protection of the environment.

Politicians have reacted to public pressure for stricter environmental regulation by introducing a regime of environmental crimes. That legislation generally binds the Crown and imposes personal liability upon directors and managers. In worst-case scenarios, 'doing your job may mean losing your home'. This paper addresses the potential common law and statutory liability of authorities/councils and their advisors. It also examines the availability of defences. Although this paper addresses all these issues with reference to New South Wales law, many of the principles have national application.

Common Law Liability The most significant common law liabilities to which authorities/councils are exposed are claims based upon negligence. An authority/council may be held to be negligent if it can be established that it owed a duty of care which existed in the circumstances and that the duty was breached, giving rise to damage.

Duty of care. The most obvious example of a duty of care owed by an authority/council is a duty to avoid injury to members of the public in the performance of its functions. Whether or not such a duty exists will depend upon the facts, and the behaviour and actions of the authority/council (via its employees) in the particular situation.

Such a duty of care was not found to have existed in the Douglas case (1). A New South Wales country town was flooded due to rainfalls of an intensity and duration not previously recorded.

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Flood prevention methods (in the form of a permanent levee bank) had been constructed by council. When the levee bank proved to be inadequate to prevent the flooding, the residents argued that the council and the Water Resources Ministerial Corporation had been negligent in failing to construct higher permanent levees.

The court held that the council was not under any duty of care to provide a greater level of protection than that for which the levee banks were designed, namely, to avoid flooding based on estimates taken from the prior record flood. Council was held to have performed adequate flood investigation works prior to constructing the levee bank.

Reliance. Generally speaking, a duty of care will arise when an authority/council places itself in such a position that others rely upon it to care for their safety or interests. Such a relationship will arise where an authority/council, by practice or past conduct, encourages reliance upon itself and imposes upon itself a duty to take positive action to protect the safety or interests of others. For example, if an authority/council has a practice of always warning affected residents of developments which may adversely impact upon them, then there may be grounds for an action against the authority/council in circumstances wher_e it has failed to give such a warnmg.

A duty of care will not be established in circumstances where no more is proved against the authority/council than a failure or omission to take some step to avert the consequences of another's negligence. In other words, an authority/council will not be negligent merely if it foresaw that damage may occur to a person as a result of another's actions but did not inform that person of the impending damage.

Of course, the position may be altered if the authority/council had a practice of issuing warnings in similar circumstances. It is well established that authorities/councils are under a duty of care to take some action, whether in

exercise of a statutory power or not, to prevent injury if their acts have created or increased the risk of injury of that kind. They will not generally be responsible for the negligent design or construction of a building or drainage system. However, if by failing to inspect the work they can be said to have increased the risk created by the defective work, they may be liable for the builder or contractor's negligence.

However, as argued in the 1985 case, SSC v Heyman (2), it must have actually increased the risk.

In 1990, a motor cycle rider sued Mt Isa Council after skidding on gravel at an intersection after rain estimated as having a frequency of one in fifty years.

The court held that the road was constructed with full knowledge of the inevitable likelihood of a dangerous situation occurring after heavy rain.

The council did not take appropriate steps (either by warning the public or clearing the road) to deal with the risk.

Accordingly, the council was found to be liable.(3).

The courts have said that the concept of general reliance is closely related to that of control. A public authority may know or should know when taking certain action that it is in a distinctly advantageous position to a,P'preciatc, assess or avoid a threat of foreseeable injury, damage or loss, compared with the position of the general public. It is likely in that situation that the concept of reliance will impose upon the public authority a duty to take reasonable care.

In such circumstances, a Water Board was held liable for untreated water becoming poisonous in a customer's lead pipe. The lrwell Valley Water Board had no statutory duty to take preventative action but was liable in negligence for its failure to do so. (4) Policy making. A public authority's policy-making decisions cannot be the subject of a duty of care. In Alec Finlayson v Armidale City Council (5), timber treatment operations caused serious contamination of land. Council rezoned the land as residential land and subsequently granted development consent for subdivision of the land for

BUSINESS Statutory immunity. Despite the Desmond's case referred to above (3), dwelling purposes. A building company sued the council for its loss when it was onerous liabilities which councils face the design engineers were held not to be revealed that areas within the subdivi- for environmental offences, s. 733 of the in breach because the design of the road sion were seriously contaminated with Local Government Act 1993 ('LGA') system and the drainage system was provides that a council does not incur satisfactory for the purposes for which it chemicals.

The court held that the council owed liability in respect of any advice was requested, namely, the disposal of a duty of care for the operational furnished by it in good faith relating to stormwater.

Environmental legislation potentially decision of granting development the likelihood of any land being flooded consent but not for the rezoning of the or the nature or extent of any such widens the scope of liability of these land which was properly characterised as flooding. The immunity covers the individuals. The legislature has reversed a policy decision. This principle can be preparation of environmental planning the onus of proof for environmental applied to councils in the exercise of any instruments (EPis), the granting/refus- offences. Automatic liability is imposed ing of consent to development applica- on directors and 'persons concerned in of their functions.

For example, the decision of a tions and the carrying out of flood the management' of a corporation, if the corporation is charged with an environcouncil (following a recommendation investigation works.

Similar immunity is extended to mental offence. This liability extends to of their catchment management committee) relating to the introduction advice furnished in good faith by the statutory corporations.

If an employee or consultant is held of a long term pollution reduction council relating to the likelihood of scheme for local waterways will not be coastal land being affected by any coastal to be a person 'concerned in the subject to a duty of care. By contrast, hazard. These laws were introduced to management ' even if not actually carryany specific construction or alteration of overcome councils' reluctance to give ing the title of 'manager', that person is the stormwater system that indirectly approvals where there was a risk that guilty of the environmental crime, for¡ causes damage to private property is natural forces might cause damage in which the authority/council was charged, unless due diligence is proved. capable of founding a negligence action the future.

However, this immunity has been In the Victorian case, Commissioner for against the council. interpreted strictly. In a February 1996 Corporate Affairs v Bracht (7), decision in Kempsey Shire Council v 'management' was held to include activStatutory Liability Regulation of environmentally Lawrence (6), the NSW Court of ities involving policy and decisiondamaging activities is now at the highest Appeal held that advice relating to the making to the extent that the conselevel on the political agenda and politi- disposal of effiuent causing damage to a quences of those decisions may have cians have responded accordingly. The person's land did not attract council's some significant bearing on the financial prime political objective is to be seen by statutory immunity because it did not standing of the corporation or the the public to be dealing firmly with relate to the flooding of the land but to conduct of its affairs.

In the same case, the phrase potential pollution of the environment. damage occurring as a result of the of the effiuent. harmful nature 'concerned in' was held to require an The result has been the introduction of The NSW Government recently involvement of some kind in the legislation creating new environmental crimes with heavy penalties and clean introduced legislation that provides an decision-making process which is more up liabilities. Regrettably, m the exemption to liability for councils in than passing and involves some responcreation of such new crimes, little regard to any action taken or omitted to sibility, but not necessarily of an thought was apparently given as to how be taken concerning 'contaminated ultimate kind whereby control 1s these environmental crimes fit in to land'. The preparation of an EPI, deter- exercised. For example, advice to traditional concepts of the criminal law. mination of a development application, management and the execution of Environmental offences. Pollution and the modification of a development decisions beyond simple followlaws, and in particular, the NSW consent are all council actions that will through of directions as an employee, Environmental Offences and Penalties not incur liability. This protection are two instances which would arguably Act 1989, create far-ranging offences extends to councillors and any person fall within the definition.

In 1993, the New South Wales EPA with a lack of precision or definition. acting under the direction of council.

However, under this new legislation, issued Prosecution Guideline$ which To give effect to the perceived legislative intention, the courts have charac- councils are only exempted from liabil- emphasised that an important factor in terised pollution laws as 'public welfare ity when exercising planning functions. determining whether the EPA will offences' thus enabling the abstracting In respect of councils' other functions, prosecute is not the management role or of principles from the law of tort. they remain potentially liable for influential capacity of the person, but Undefined words have been given the environmental crimes and substantial whether there is evidence linking the widest possible meanings and in many penalties. Similarly, the protection person with the corporation's unlawful cases, pollution laws have been afforded by the new legislation does not conduct. There is scope for a consultant construed according to their context, extend to those decisions of council or an engineer to fall within the scope of thereby departing significantly from dealing with waterways. Finally, if a this test. council fails to act in 'good faith', they Section 731 of the LGA provides that traditional concepts of criminal law. not be protected. will a councillor, an employee or person Environmental legislation provides acting under the direction of the for three 'tiers' of offences, of varying Liability of Employees and council is not, ifhe or she acted in good degrees of seriousness. Maximum faith, subject to any liability or claim. penalties for serious offences are Consultants Introduction. At common law, those The onus of showing that councillors or currently $1 million for corporations and $250,000 and/or 7 years imprison- persons who advise authorities/councils employees did not act in good faith is may be liable for their acts that consti- likely to rest on the complainant. In this ment for individuals.

The only realistic defence to these tute a breach of the duty of care owed to situation, 'good faith' will be presumed offences is for the authority/council to the public. However, even if the if the person acted substantially in demonstrate that it exercised 'due authority/council is found liable, the accordance with the principles of the diligence'. This concept will be independent engineer or consultant is relevant Ministerial or council policy in not also automatically liable. In force. discussed in detail below.

WATER JANUARY/FEBRUARY 1997

37.

BUSINESS Environmental consultants. Councils, due to their broad responsibilities, do not have the appropriate skills to make environmental decisions without extensive consultation with environmental experts. Drainage and flooding studies and environmental impact studies are examples of tasks which are commonly referred to consultants.

If the recommendation of these consultants is consistently adopted without serious consideration and discussion of the issues, courts may find that the consultants are involved (in a more than passing manner) in council's decisions.

Pursuant to s. 731 LGA, 'a person acting under the direction of the council' who acts in good faith will not be liable for their actions. Whether a non-council employee is 'a person acting under the direction of the council' will be a question of fact depending on the circumstances.

There is scope for consultants to be personally liable in situations where they prepare reports for a third party which are then relied upon by council in its decision-making process. In these situations, the LGA immunity will probably not apply.

Engineers. In the smaller authorities/councils, in-house engineers have a greater degree of responsibility. In implementing works programmes, engineers are often delegated power to make decisions regarding the drainage and road system, providing the decisions are within the budget. This degree of autonomy may arguably lead to engineers being personally liable for environmental offences. Subsequently, authorities/councils may be vicariously liable.

Although this lack of accountability raises risk management issues, most authorities/councils do not confer any decision-making authority on either engineers or committees.

Furthermore, the courts seem reluctant to give a 'loose' interpretation to persons 'taking part in the management' of a corporation, particularly since the section imposes criminal liability. It is necessary to consider the precise role which the person played in the corporation, rather than simply the title or the position which the person occupied in the corporate structure. There must be a fact, matter, or circumstance which shows that the person had taken part in the management of the company.

(Holpitt Pty Ltd v Swaab (8)).

In most situations an engineer is likely to be either an 'employee' or a 'person acting under the direction of the council'. Legal actions against engineers will therefore be precluded by virtue of theLGA.

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Defences Introduction. If the LGA immunity does not apply, persons held to be concerned in the management of an authority/council are deemed guilty of an offence even if the authority/council is not prosecuted. Persons who have been held to be persons 'concerned in the management' must establish one of the following defences: â&#x20AC;˘ an absence of knowledge â&#x20AC;˘ a lack of influence or, most importantly â&#x20AC;˘ that they have exercised all due diligence.

Due diligence will, in many situations, be the only available defence for either consultants or engineers.

Due diligence. Whilst due diligence is a defence to an environmental crime for which a corporation and its directors or persons concerned in its management are prosecuted, it is not defined in the legislation. Whilst the concept of due diligence is well known in a number of different areas of the law, the development of the principle has been left to the courts and concepts from the common law have been introduced.

The question repeatedly arises as to whether due diligence should be measured by an objective or subjective standard. The leading case of SPCC v Kelly (9) held that: 'due diligence depends on the circumstances of the case, but contemplates a mind concentrated on the likely risks. The requirements are not satisfied by precautions merely as a general matter in the business of the corporation, unless also designed to prevent the contravention. Whether a defendant took the precautions that ought to have been taken must always be a question of fact and, in my opinion, must be decided objectively according to the standard of a reasonable man in the circumstances. It would be no answer for such person to say that he did his best given his particular abilities, resources or circumstances.'

In order to take the benefit of the defence, the accused must demonstrate that at the time of the offence, there was in existence an appropriate system of environment management. The absence of such a system will almost inevitably result in conviction. It will be necessary to demonstrate that 'the mind' of management (whether it be via an independent consultant or the authority/council itself) was concentrated on the likely risks which would foresee the actual breach.

In 1991, an employee of a tip contractor breached a leachate dam at the council's tip with a bulldozer (SPCC v Blue Mountains (10)). This caused tip leachate to flow into and pollute local waters which were 'classified waters' under the Clean Waters Act

1970 (NSW). The council successfully pleaded the defence that it was impracticable to make provision for the happening of the incident. In 1996, it is doubtful whether the council would now be successful unless there was a system of environmental management that provided some form of training or supervision for contractors and their employees. If the breaching of the dam is a 'likely risk' that council had not contemplated, both the council and the tip contractor would probably be liable for the offence.

Conclusion Given that the protection of the environment will be continually considered an area of increasing importance and one of high public exposure, environmental offences will be commonly prosecuted and will incur significant penalties. Authorities'/ councils' liability for those actions causing environmental harm is likely to increase rather than decrease. The limited immunity offered by legislation will not protect authorities/councils from liability for many of their actions.

Despite the deemed liability imposed by environmental statutes, in a majority of situations, consultants and employed engineers will not incur liability for their non-fraudulent advice.

The only viable defence when they are prosecuted is that they exercised due diligence. An awareness of the risks and the implementation of a system of environmental management will need to be demonstrated.

Cases Cited 1. Douglas & Anor v Bogan Shire Council and Water Resources Ministerial Corporation (1994) 82 LGERA 305.

2. SSC v Heyman (1985) 157 CLR 424@ 479 3. Desmond v Mount Isa City Cotl~cil (1990) 70 LGRA335 4. Barnes v Irwell Valley Water Board [1939] 1 KB 21 @45 5. Alec Finlayson v Armidale City Council (1994) 123 ALR 155 6. Kempsey Shire Council v Lawrence (1996) Aust TortsR 81-375 7. Corporate Affairs v Bracht (1989) VR 821 8. Holpitt Pry Ltd v Swaab (1991) 105 ALR..421 9. SPCC v Kelly (1991) ALJR 607 10. SPCC v Blue Mountains (1991) 73 LGRA 337

Author Noel Hemmings QC is a Partner at Allen Allen & Hemsley, Sydney and Chairman of its Environment and Planning Group. He practised as a Barrister} then as QC,for more than twenty yea,:s. In 1987 he was made Judge of the Land and Environrnent Court ef NSW. He joined Allen Allen & Hemsley (GPO Box 50, Sydney) in 1991.