Water Journal March - April 1999

Volume 26 No 2 March/April 1999 Journal Australian Water & Wastewater Association Editorial Board F R Bishop, Chairman B N Anderson, D Deere, P Draayers, W J Dulfer, G A Holder, M Muntisov, P Nadebaum, J D Parker, M Pascoe, AJ Priestley, ] Rissman, F Roddick, E A Swinton

·, Water is a refereed journal. This symbol indicates that a paper has been refereed.

General Editor Margaret Metz, email: nunetz@awwa.asn.au AWWA Federal Office (see JXlStal address below)

Features Editor EA (Bob) Swinton 4 Pleasant View Cres, Wheelers Hill Vic 3150 Tel/ Fax (03) 9560 4752 Email: swintonb@c031 .aone.net.au

Branch Correspondents ACT - Ian Bergman T el (02) 6230 1039 Fax (02) 6230 6265 N ew South Wales - Leonie H uxedurp Tel (02) 9895 5927 Fax (02) 9895 5967 N orthern Territory - Mike Lawton Tel (08) 8924 64 11 Fax (08) 8924 6410 Queensland - Tom Belgrove Tel (07) 3810 7967 Fax (07) 3810 7964 South Australia - Angela Colliver Tel (08) 8227 1111 fax (08) 8227 1100 Tasmania - E d Kleywegt Tel (03) 6238 2841 Fax (03 6) 234 7109 Victoria - Mike M untisov T el (03) 9278 2200 Fax (03) 9600 1300 Western Australia- Jane Oliver Tel (08) 9380 7454 Fax (08) 93881908

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Water (ISSN 0310 • 0367)

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

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!UP\id

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

POINT

OF

VIEW

Making the Intangible Tangible ....... .. ... .. .... ................ ....... .. ........... ...... ......... 3.

A Makris WATER Water Solutions .............. ................................................ .................... ............. 7 C Allen ·, Identifying Cryptosporidium Using DNA Methods ... ....... ... .. ... ...... ..... .-.... 9 U Morgan, R C A Thompson ·, Water Treatment Options for Cryptosporidium and Giardia ........... ... .. 11 B Murray, K Linneman n, K Craig [ ·, Bioavailability of Aluminium In Alum-treated Drinking Water and Food ............... ............................ ................. .... ............ .. ... .......... ..... ......... 17 J L Stauber, CM D avies, MS Adams, S J Buchanan, TM Florence Asia Water Comes to Sydney ... ... ..................... ...................... ...... .... ..... ....... 23 C D avis WASTEWATER ~ Groundwater Contamination from Effluent Irrigation ... .. ............. ........ 26 VO Snow, P J D illon, W J Bond, CJ Smith, B J Myers Sustainability and 'SNABWEMs' .... .............. ... ............. ...... ...................... .... 31 M Laginestra ENVIRONMENT

......

Federal President Greg Cawston

Executive Director C hris D avis Australian Water & Wastewater Association (AWW A) assumes no responsibility for opinions or statements of facts expressed by contributors or advertisers. Editorials do not necessarily represent o ffi cial AWWA policy.

Advertisements are included as an information service co readers and are reviewed before publication to ensure relevance to the water environment and objectives of AWWA. All material in Water is copyright and should not be reproduced wholly or in part without the written pennission of the General Editor.

Subscriptions Water is sent to all members of AWWA as one of the privileges of membership. Non-members can obtain W,1ter on subscription at an· annual subscription rate of S50 (surface mail).

Ozone Water Treatment Used to Save Rare Queensland Frog ... ... . ... ... .. . .. 33 P Barlow [ ·f Protecting Inland Waterways: Environmental Management at Lower Molonglo .................... ...................................................... ........ .......... .. 35 R H ogg, A Wade, A Wijeratne BUSINESS "·, Water Markets: Buyer and Seller Perceptions ......................... ..... ........ 41 H Bjornlund , J McKay DEPARTMENTS International Affiliates ...... ..... ............................................................. .......... 5 From the Bottom of the Well ........ ....... .... ...... .... .. ............................... ........... 4 Meetings ... ........... .......... ... .. ... ...... ..... ... .............. .. .... ....... .. .. .. ..... .... ......... ... .... 49 Books ................. ............. ............ ... .......... ... ...................... ... ... ......... .... ...... . 8, 30 OUR COVER: Fleayi's Barred Frog (Mixophyes fleay1) is in danger of becoming extinct and the water industry is doing its b est to ensure the survival of this rare Australian species. In cooperation with Lone Pine Koala Sanctuary, Sea World and th e Queensland D epartment of Environment and H eritage, Ionics Watertec has designed a water filtration and ozo nation system that removes pathogens and reproduces th e pristine water quality of the frog's rainforest stream habitat as an essential part of a captive breeding program to be undertaken over the next five years. Photo courtesy of Eric Vanderduys of the Queensland Museum and Ionics

W atertec.

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U Morgan, RCA Thompson

collected over 400 different isolates of Cryptosporidit1m is an intestinal Cryptosporidit1m, of which approxiparasite found in humans and animals. mately 300 have been characterised It m ultiplies within the surface layers genetically or 'genotyped.' of the host's small intestine, causing At present, at least seven genotypes damage w hich may lead to severe of C. parvum have been identified: a diarrhoea. When this ti ny (5 Âľm) 'human' genotype which has so far single- celled protozoan parasite leaves been fo und only in humans; a 'cattle' its host, a tough outer shell favours its genotype found in domestic livestock survival during routine water an d such as cattle, sheep , goats etc. and wastewater di sinfectio n and treatwhich can also infect humans; a ment. 'mouse' genotype that has been found Cryptosporidit1m has co me to in mice from around the world and prominence in Australia as a result of more recently 111 bats; a pig Cryptosporld/um and Giard/a In the small the recent contamination of Sydney genotype; a 'marsupial' genotype th at water supplies, but came to world Intestine has been found in koalas and kangapro m inence in 1993 whe n over both genetically and biologically. It is roos; a 'dog' genotype; and a 'ferret' 400,000 people in Milwaukee, USA possible that these strains will be classed genotype. became infected with it as a result of as new species in the near future.

So fa r only the 'human' and 'cattle' drinking contaminated drinking water.

Currently, our research in the genotypes have been found in healthy Amongst AIDS patients who contracted Division of Veterinary and Biomedical human beings, and the public health cryp tospo ridiosis as a result of th is Scienc es at Murdoch University significance of the remaining genotypes outbreak, the outcome of disease was involves cha racterising the is unknown (see Figure 1). Since most severe, w ith 52% to 68% of people Ciyptosporidium fou nd in a variery of of these ' new' genotypes appear to be dying within six months to a year after hosts using sensitive DNA-based detec- host-specific, they are unlikely to infect the outbreak. Since t his epidemic, tion methods. As part of our role as a people with intact immune systems. It Cryptosporidit1m has been the subject World Heal th Organisation is possible, however, that individuals of an enormous amount of research Collaborating Centre for the Molecular with deficient immune systems such as wo rldwide and has the unusua l Epidemiology of Parasitic Infections, AIDS patients may be su sceatible to distinction of having its own we have been collaborating w ith a wide other Clyptosporidiwn genotypes. magazine, C1yptosporidit1m Capsule variery of National and International Current methods for identifying (http://www.fspubl.com).

R esearc h Ce ntres, including the Cryptosporidium in water supplies Despite the vast amount of research Centres for Disease Control (CDC) in generally rely on immunofluorescent that has been conducted, there is still a Atlanta, USA, and we have now microscopy and/or flow cytometry, in great deal that we do not know about which fluorescent antibodies bind Ciyptosporidium. At present up to to Cryptosporidium and diagnosis eight species have been recognised: is made on the basis of morphologC. muris which infects mostly ical characteristics. H owever, rodents but also cattle and other because all the genotypes of C. hosts; C. wrairi w hi ch infects parvum are morphologically identiguinea pigs; C. meleagridis and cal, they cannot be differentiated C. baileyi in birds; C. serpentis in using these techniques. This can reptiles; C. nasornm in fish; C. [elis be done using DNA- based only in cats and C. parvum in humans techniques. and other mammals.

If we can determine the Cryptosporidium parvum is the genotype of Cryptosporidium most widely stud ied species. In the found in water supplies, this will last couple of years it has become not only tell u s if parasites that are increasingly clear that C. pa1-vt1m is potentially infectious to humans not a single species but is are present, bu t it will give us Purified Cryptosporidlum oocysts (arrow shows composed of a number of distinct information about their source. single oocyst) 'strains' (or genorypes) th at differ WATER MARCH/APRIL 1999

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Transmission of major Cryptosporidium genotypes C. parvum

Figure 1 Transmission dynamics of Cryptosporidium

For example, if the 'human' genotype is detected, it must have come from human faecal co ntamination of the water; if it's the 'marsupial' genotype, it may have come from marsupials in the catchment area; and so on.

R esearch to date on a number of waterborne outbreaks in the UK and USA , including the famous Milwaukee outbreak , has indicated that most waterborne outbreaks have been caused by the ' human' genotype.

Future genetic and biological characterisation studies are required on a wider range of isolates in order to confirm the distribution of these genotypes and to determine if they are in fact separate species. Ongoing human-infectivity trials in the USA will also provide important information as to the public health significance of the 'mouse', 'pig', 'marsupial' 'ferret', and 'dog' genotypes.

Authors Dr Una Morgan is a molecular biologist and Professor R C Andrew Thompson is a parasitologist with the World H ealth Organisation Collaborating Centre for the Molecular Epidemiology of Parasitic Infections and State Agricultural Biotechnology Ce n tre, Division of Veterinary and Biomedical Sciences, Murdoch University, Murdoch WA 6150.

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Cryptosporidium for sale Purified, freshly passaged, viable Cryptosporidium oocysts suitable for standardisation are now available on a regular basis from Murdoch University at a cost of $500 per 6 million oocysts.

For more information contact:

Dr Una Morgan morgan@numbat.murdoch.edu.au Fax:(08) 9310 4144 Tel: (08) 9360 2457 Prof. RCA Thompson andrew t@numbat.murdoch.edu.au Fax:(08) 9310 4144 Tel: (08) 9360 2466

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WATER TREATMENT OPTIONS FOR CRYPTOSPOR/0/UM AND GIARD/A B Murray, K Linnemann, K Craig

Abstract The

protozoa n parasites Cryptosporidium and Giardia are found in catchments and groundwater worldwide , and have recently caused widespread co ncern following their detection in Sydney. Treatment is made di ffi cult by their resistance to normal di sinfectio n measures (especially Cryptosporidium) and their relatively low infective dose.

T here are trea tme nt options w hich, combined W1th appropriate catchment n1anagement and storage, will reduce the risk of these organisms entering the treated water system. Optimisation of co nventional filtration systems is fea sible, using particle counting instrume ntati on w hich is faster and m ore economical than counting th e actual oo/cysts. Advanced treatment technologies may be incorporated into new or existing treatment processes. T his paper reviews the rem.oval efficiencies of such system s.

Introduction

C1yptosporidium and Giardia are parasitic protozoa whic h are found worldwide and may be p resent in most ca tchmen ts and groundwater in Australia, with the poten tial risk of contamination of urban and ru ral water supplies. T he organisms can only reproduce inside the gu t of animals (including hu mans) . However, Giardia cysts may survive in water for several months and Crypto sporidiwn oocysts m ay survive even longer, especially at low temperatures.

The species of these protozoa w hich cause illness in humans are generally Cryptosporidiwn parvum and Giardia lamblia. D espite a lack of clear correlatio n b etween illness o utbreak s and levels of oo/cysts in water, both are known to have a relatively low infective dose (Craun et al., 1998).

R ecent studies have shown that rainfall can increase the concen tration of protozoan oo/cysts in rivers by a number of pote ntial m echanisms, inclu ding re- su spe n sion of bo ttom sediments, soil and faecal matter and sewage system overflows (Atherholt et

al. , 1998). T h e high levels of Clyptosporidium oocysts and Giardia cysts repo rted in Sydney's water supply system. in winter 1998 followed high rain fall even ts in the catchments.

Giardia cysts can n ormally be controlled through effective physical removal and adequate chemical inactivation.

Cryp tosporidium oocysts, however, are smaller than Giardia cysts and therefore m ore difficult to physically remove. They are al so almost completely resistant to chlorine-based disinfectants at normal concentrations and contact times, (see Table 1, from Langlais et al, 1991) and have been reported to survive 24 hou rs at a chlorine concen tratio n of 1,000 mg/L (Smith et al. , 1989).

Protection of Raw Water Supplies The main focus of this paper is the op tions fo r trea tment p rocesses.

However, for maximu m protection against waterborne Cryptosporidium and Giardia, there must be appropriate management of ca tchme nt, reservoir and reticulation, supported by effective

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oo/cysts ca n concentrate in layers or pockets in reservoirs, parti cularly w hen there is a drought followed by heavy rainfall. Therefore, m onitoring at various depths of a reservoir is required, especially after heavy rain. Multiple drawoff levels w ill offer advantages in th e cleanest wate r. selectin g D estratifica tion syste ms may be investigated to de te rmine t heir effect on Cryptosporidium and Giardia. The water circulation provided w ill not only dilute concentrated pockets of oo/cysts bu t may also inactivate some oo/cysts by exposure to air and ultraviolet light.

The water distribu tion system should be secured against re- contamination with sources of protozoan cysts. This can be achieved by regular ma intenance and monitoring and back0ow prevention . Biofilms on pipe surfaces may harbour protozoa w hi ch m ay be sloughed off by higher velocities.

Effective Water Treatment If the raw water source is considered likely to become contaminated with Cryptosporidium and Giardia, a

Table 1 Ct values for 99% inactivation at 5° C (mg. min/ L)

Organism

Cl 2

0.034- 0.05 E.coli 1.1-2.5 Polio v.1 0.01-6,480 Rotavirus 7.7 Naegieria 7,200 Cryptosporidium oocysts (90%) 30-630 Giardia muris cysts

monitori ng of raw and treated water and community health surveillance.

Effec tive catchment managem ent would aim to protect the water source from contamination with human or animal faeces. Agricultural, residential, forestry and mining developments may be potential sources of faecal or other types of contamination in water supply catchments. A catchment-wide body with appro priate respon sibilities and powers may provide the best protection of water quality (McClellan , 1998).

Cryptosporidium and Giardia

Chloramine 95-180 770-3,740 3,810-6,480

-

7,200 1-400

CI0 2

Ozone

0.02 0.4-0.75 0.2-0.6.7 0.1 - 0.2 0.2-2.1 0.006-0.06 3.7 0.75 78 5.0 7,2 - 18.5 1.8-2.0

number o f short- , medium - and longte rm optio n s may be adopted to improve th e p erformance of water treatment plants (WTPs) for e nhanced removal of these organisms.

A rapid resp onse to treating poo r quali ty water is shutting down the W TP after rain when very high turbidities are encountered or if high levels of Giardia or C1yptosporidium in the source water are suspec ted. This is feasible only if adequate raw and treated water storage capacity is available.

Short- to m eclium- term approaches WATER MARCH/APRIL 1999

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WATER involve optimisation of the plant's process. Well-operated conventional treatment and direct/contact filtration plants can be expected to achieve 2 to 3 log removal of cysts and oocysts. Many plants, however, may only achieve 1 to 2 log removal.

Medium - to long-term water treatm ent approaches may include additio n of new, more effective treatment barriers for Cryptosporidium and Giardia.

Several researchers have examined a variety of treatment technologies which will provide furt her barriers to Giardia and Cryptosporidium in the water supply, some of which are discussed below.

can be used to provide information and feedback for: • evaluation of WTP performance for the removal of cysts • chemical dosing and process optimisatio n • initiation of backwashing • monitoring filter ripening times.

Proprietary software is normally provided by particle counter suppliers, enabling particle counting information for various particle size ranges to be logged and manipulated. T he software allows links to a WTP's central SCADA system, alarms and/or control systems for backwashing or filter-to-waste of ripening water.

Particle Counting Instrumentation M onitoring to identify and achieve optimal performance should preferably incorporate particle counting information and turbidity measureme nts.

Particle counting has several advantages over turbidime t ry becau se i t defines a greater n umber of parameters, covers a greater order of magnitude of results, and is more sensitive to water quality.

Particle coun ters meas ure the nu mber of particles p er specifi ed volume of water, loggi ng seve ral parti cle size ba nd s simultaneously.

T hey can give an instantaneous and low- cost indication of particle concentration in the 2- 12 µm size range of protozoan oo/cysts far more economically t han measurem en ts of actual oo/cysts. An illustration of the early breakth rough of particles in the oocyst range no t detectable by tu rbidity m easu reme nt is given in Figure 1, derived during p ilot trials fo r the Prospect T reatment Pla n t (Murray, 1994, 1995).

Raw water p article counting ca n provide early warning of contamination. Particle counting of filtered water

Water Treatment Process Optimisation Operational approaches to optimise the removal o f Cryptosporidium and Giardia oo/cysts include: • optimising chemical dosing • minimising the effect of flow rate changes • optimising filter design and backwashi ng technique • minimising fil ter ripening • minimising recycli ng risks.

Ma ny o f these options may be employed at established plants, depending on the design and layou t o f the plant. Some o ption s sho uld also be considered in the design of new W TPs. Studies have shown that optimised conventi onal treatment and even direct/contact fil tration p rocesses can achieve up to 4 log removal of oo/cysts.

O ngerth and Pecorano (1995) fo und that direct filtratio n with dual media under optimised con ditions cou ld achieve approximately 3 log removal for Cryptosporidium oocysts and slightly better fo r Giardia. Sydney Water (1993) fou nd 4 log removal was achieved for high concentration slugs of Cryptosporidium oocysts in dual media con tact

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filtration. Nieminski and Ongerth (1995) fou nd 2.9 log removal of Cryptosporidi um oocysts in pilot trials of both conventional filt ration with sedimentation and direct filtra tion.

Full-scale trials showed 2 .3 log removal by conventional treatment and 2.8 log removal by direct filtration. Plummer et al. (1995) found 2 to 3 .7 log removal of oocysts with bench- scale OAF dependent on coagulant dose.

Optimising Chemical Dosing

In o rde r to optimise removal of Cryptosporidium and Giardia, t he cont rol of chemical dosing for p H correction, coagulation and filter aid should be based on filtered water particle counts as well as turbidity.

T here are several additional tools fo r optimising coagulan t dose rates, including streaming curre nt detecto rs (SCDs) and zeta potential meters. T hese instruments can help determine the optimal coagulant dose by ind icating the point of charge neu tralisation in water downstream from dosing. They can provide on-li ne feedback on coagulati on effectiven ess , which would no rmally require jar- testing or other analytical tests. H owever, significant on-site testing is often necessary for accurate in te rpretatio n o f the SCD outputs into useful water quality information.

As well as optimising dose rates for chemicals, p article counting and other information should be u sed to optimise the other plant parameters which affect the process performance, including: • coagulation mi xing e nergies-to maximi se incorporation of particulates i nto the floe and to maximise floe strength • co ntact time fo r flocculation- to achieve optimum floe size for removal in the filters • filt ration rate-t o m inim ise floe shearing.

Choice of coagulant m ay be another consideration in optimising chemical use in the WTP. Ferric coagulation differs from alum coagulation in that ferric floes are usually larger and mo re fragile than alum floes. Ferric floes are therefore more prone to shear and break t hrough the fi lter beds, and ferric typically give shorter run times than alum due to build-up oflarge floe in the upper part o f the filter beds. Cati onic polyme r used w ith fe rric chlori de produces a stronger and smaller floe that is suited to contact filtration, making longer filter run times possible.

Minimising the Effect of Flow Rate Changes

0.0 1 _,____ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ __ _ _ _ _ _ __._

0 1 2 3 4 5 6 7 8 9 101112 13 141 5 16 17 18 19202 122232425262728293031 32333435363738394041 4243 Run Time (h)

Figure 1 Comparison of t urbidity and particle count 12

WATER MARCH/ APRIL 1999

Flow rate changes commonly occur in water treatment plan ts during start- up, during sudden increases in W T P flow rates or when a filter is taken off-line for backwashing . T h ese cha nges may

WATER increase th e risk of Cryptosporidium or Giardia oo/cysts passing through the filters.

Sudden increases in flow rate through the filters lead to higher interstitial velocities within the filter media, te nding to shear the floe and carry turbidity and particles t hrough the filters. Rate changes m ay also dislodge any deposits in tanks, pipelines or channels of the WTP. Areas of a WTP wh ere sedimentation may occur sh ould be maintained by regular cleaning.

Staged ramp- up times are commonly e mpl oyed to minimise rapid flow changes during start-up of a WTP or increases in the WTP's flow rate. When one filter goes out for backwashing, however, the filtration rate in the other filters increases by a percentage that depends on the number of filters.

Several options are available in most WTPs to reduce flow changes when a filter is backwa~hing. T hese include: • reducing or stopping plant flow while backwashing is occurring. This option modifica tion to the requires PLC/SCADA software in o rder to impleme n t it. T he WTP's water production rate would, however, be reduced and frequent changes to the raw water chem.ical dosing rates would be required with the plant flow changes, m aking this option undesirable • increasing fil ter aid doses to the operating fil ters. Filter aid doses may be increased in proportion to the filtration rate to assist in minimising the effect of increased filtration rates. Stu dies have shown this approach to have some value bu t it would increase chemical operating costs • e mploying a spare filter to replace the filter that is backwashing. If the WTP has sufficient capacity to be operated at design filtration rates with one filter as a spare, the sp are filter can be brought on-line to replace any fil ter going out for backwash. An advantage of this option is that the newly backwashed and now spare filter could continue to have coagulated water flow nm through it at a low rate. Thus it would have a slow start and would ripen prior to being brought fully on-line. The small volume of ripening water flowing to the finished water would be well diluted by the other filters operating at their op timum. The spare filter option would, h owever, diminish the capacity of the WTP to treat fut ure high demands and would also reduce the capacity of the plant to h ave one filter o ut for main ten an ce unless an additional filter were installed at the WTP.

cysts and oocysts. Any small particulates carrying through or sheared off the floe in the coal bed are expected to be trapped in the fi ne sand.

Inadequate filte r backwashing can lead to a risk of Cryptosporidium and Giardia entering the filtered water due to the gradual buildup of sludge or mud balls in the filters and the subsequent carry-through of these solids, which may include oo/cysts. It is therefore importa n t to ensure satisfacto ry backwashing of the filters, including adequate air sco ur and water wash periods. Any trend to increased clean bed headloss will indicate gradual accu m ulation of solids in the filter media and the need fo r backwashing optimisation.

Backwashing is normally initiated based on fil tered water turbidity or headloss accumulation across the filters. breakthrough, however , Particle typically occurs before turbidity breakthrough at the end of a filter run, in some cases several hours ahead (Murray, 1994). Backwashing initiation based on filtered water particle counts rather than turbidity should therefore be conside red to lesse n the ri sk of oo/cysts passing into the filtered water. T he particle count level set fo r backwashing would best be determined from detailed analysis of the filtered water particle count.

It must be n oted, h owever, that this would sho rten filter runs, reduce production effi ciency and impose a greater load on the wastewater handling system.

Minimising Filter Ripening

Sand or dual media fil ters have to undergo a ripening period when back on-line after backwashing, due to the partially dirty backwash water remaining in the filters, and the need to condition the media by build- up of coagulant floe and particularly filter aid polymer in the filter bed, increasing the bed's effectiveness.

During th e ripening period, high turbidity and particle co unts are measured in the filtered water , reducing steadily as the fil ter ripens. T ypically, particle counts may remain h igh for a significant ti me after the guideline turbidity value has been achieved.

During filter ripening, reprogramming of the PLC/SCADA-controlled backwash cycle should be required to incorporate a p eriod (0- 60 min u tes) after a backwash, during which time the first filtered water flow is diverted from the filtered water system. ripening-to-waste water T he mentioned above is of a much h igher Optimising Filter Design and Back- quality than the backwash water, and if all of it were wasted, the capacity of the washing Technique D ual media filters may give added W TP would b e down-rated.

Polymer can be dosed in to the protection against the breakthrough of

backwash water to pre- condition the media in the filters before the filter run is started. A polyacrylamide polymer is normally employed and dosed into the last two to three minutes of backwash water at optimised d ose rates determined in plant trials. With pre-conditioning, the media would achieve better particle removal performance during the filter ripening period. The risk of Cryptosporidium and Giardia oo/cysts passing through the filter during the ripening p eriod would thus be reduced without requiring filter-to-waste.

Another option would be to slowstart a filter after backwashing.

Experience has shown that good water quality can be achieved from a clean filter if it is started at a sufficiently low rate w hich is gradually increased until it runs at the design rate. T his puts less pressure on the floe fo rming within a filter bed and minimises shear of the floe. Some level of filter ripening m ay still be experie nced, h owever, due to the initial dirty washwater in the filter bed.

The other advantage of slow- starting a filter afte r backwashing is that the fil ter co ntributes little water to the overall filtered water volume and the dilution factor is therefore greater than would normally be provided. Slowstarting a filter would only require reprogramming of the SCADA/PLC w ith no additional infrastructure required.

T he disadvantage of slow starting a filter is that the maxim um capacity of the WTP is reduced by the amount of water not treated duri ng the slow start.

Minimising Recycling Risks

Supernatant from backwash water thickeners, underflow from drying beds and centrate from centrifuges at WTPs are comm only recycled back into the treatment plant process. The recycling of waste streams carries the risk of oo/cysts or other contaminants removed by filtration being re-introduced and concentrated in the water flo w through the WTPs. With an increased number of o o/cysts in the water treated by the WTP , the potential for oo/cysts to break through into the filte red water is also inc reased, especially if the cysts are returned in concentrated bursts.

The following options are available: • optimisation of wastewater system performance and continuous gradual return of supernatant water • disposal of supernatant to waste • trea tment to remove/inactivate oo/cysts before return to the head of the works.

Supernatant may be disposed of to the sewer or reused if suitable reuse options exist. Disposal options would also require approval from the relevant WATER MARCH/ APRIL 1999

13

WATER authorities. Further, if supernatant is disposed of rather than being recycled in the plant, the capacity of the WTP would be reduced and additional raw water would need to be pumped to the WTP. Supernatant Treatment

Treatment options for return supernatant water include membrane filtration, ozonation, UV and proprietary filtration systems.

These methods are discussed in more d etail in the next section.

Advanced Treatment Options Technologies w hich may be incorporated into conventional treatment or d irect/contact treatment process designs to aid the removal or inactivation of oo/cysts include: • microfiltration • ozonation • ozone+ biological carbon (BAC) • combined oxidants • UV treatment • proprietary filter designs.

These technologies may be inco rporated into the design of new water treatment facilities or retrofitted to existing plants .

In direct-contact filtration plants, addition of a pre- sedim entation stage may increase the effectiveness of treatment, especially during dirty water events.

Membrane Filtration

Microfiltration is commonly seen as the appropriate m embrane technology for the removal of Giardia cysts and Cryptosporidium oocysts. Nanofiltrati on membranes have eve n smaller pores than microfiltration membranes, and thus have the advantage o f being able to remove additional con taminan ts such as taste and odour compou nd s and algal toxins and p esticides.

Nanofiltration and reverse osmosi s are complete barriers to cysts and oocysts.

Microfiltrati on, with a typical m embran e pore size of 0 .2 mm, provides a physical barrier to Giardia and Cryptosporidium oo/cysts.

U l trafiltrati on and microfiltration membrane processes have been shown to produce 6 log removal or greater of oo/cysts Qacangelo et al. , 1995). Some manufacturers will guarantee 4 log removal of Cryptosporidium oocysts and Giardia cysts by m embrane processes. T he US EPA credits microfil tration with 3 log removal.

A disadvantage of m embrane treatment is the substantial waste stream, possibly heavily loaded with active oo/cysts, salts and other m inerals, which may be produced. This waste would have to be disposed of in a suitable manner, or further treated.

Alth ough effective, m embrane processes are expe nsive . Prototyp e 14

WATER MARCH/APRIL 1999

nanofiltration plants have been incorporated into plants in Europe to treat filtered water fo r pesticide removal in replacement of the ozone-BAC process.

Both capital and operating costs for nanofiltration are more expen sive than (C raig, 1994; for ozon e/BAC AmWWA, 1994).

Operation costs for microfiltration are relatively high becau se o f the replacement costs of the membranes, as well as power co sts for pumping, and maintenance costs including chemical cleaning. The life of m embranes i s expected to b e th ree to five yea rs, requiring m ajor expenditure at this stage. H owever, the costs of membrane processes are likely to become more econ omical in the future and m ay become viable options.

Pre-coagulation Ozonation

Prior to coagulation, ozo nation provides disinfection and also commences micro-flocculation , thereby improving the effectiveness of coagulation, filtration and particle removal. An ozone dose of 2-3 mg/L in settled water has been reported to improve the particle removal for sand filtration by 90% in the 2-1 0 µ m particle size range (Bourgine et al. ,1996).

Ozone's effectiveness as a disinfectant and coagulating agent depends on the quality of water treated , influenced in particular by the TOC and calcium hardness levels in the water (Langlais, et al. 1998). Pilot plant testing wo uld therefo re normally be required to ascertain the feasibility of pre- coagulation trea tment with ozone for specific water sources.

Manganese removal by oxidation is also e nhanced by pre- coagulation ozonation.

Ozone BAC

Ozone ca n effectively achieve 1 to 2 log inactivation of Cryptosporidium oo cysts in filtered water with sufficient contact time.

BAC after ozone is preferred to protect the reticulation from excessive microbiological growth since ozone breaks down organic compounds into readily assimilable compo ne nts on which micro-organi sms thrive. BAC also provides further removal of particles and still-active cysts. An empty bed contact time (EBCT) of 10-15 minu tes is commonly provided in the BAC contactors. Ozone BAC system s effectively remove contaminants su ch as pesticides, THMs, BDOC, taste and odour compounds, and algal toxins.

They also minimise regrowth in the water supply system.

The ozonation Ct (ozone concentration x contact tim e) required for inactivation of oo/cysts at various temperatures are summa rised in T able 2.

(La nglais e t al. , 1991) Typically for Australian temperatures i t should be in the order of 5 to 7 mg.min/L to achieve 2 log removal and 2.5- 3.5 mg.min/ L for 1 log removal, i.e. a contact time of at least 15 minutes would be required in co njunction with an ozone residual averaging 0.3-0.5 mg/L. If the BAC filters are used mainly as biological contactors, rath er than adsorbers for micropollu tants such as pesticides, the GAC m edia may not require replacement or regen era tion du e to the biological processes on th e media, but it would occasionally require topping up due to losses from backwashing .

Sodium bisulphite may be required to de- ozonate the water prior to BAC. Otherwise, growth of th e mic roorganisms in the BAC filter may be discouraged by the residual ozone.

A furthe r potential treatment option is the co mbination of a pre-ozone stage with ozone BAC. This system would increase particle removal and oo/cyst inactivation.

Combined Oxidants

While Ciyptosporidium oocysts are highly resistant to chlorine disinfection, studies have shown that combinations

Table 2 Ct Values for Cryptosporidium inactivation with ozone Temp.

3° C 7° C 15° C

20° C

Log10 reduction

2: 2: 2: 2: 2: 2: 2: 2: 2: 2: 2: 2: 2: 2: 2:

2 3 4 2 3 4 2 3 3 4 4 2 3 4 4

Dissolved 0 3 concentration (mg/L) Final Initial

1 .22 1 .52 2.10 0.82 1 .12 1 .50 0.46 0.62 0.82 1 .51 1 .21 0.46 0.83 0.61 1.10

1.16 1.47 2.05 0.78 1.08 1.45 0.42 0 .58 0.78 1.47 1.18 0.42 0.78 0.5 1.08

Exposure time (min.)

(mg.min/L)

7 8 10 6 8 8 6 8 6 4 5 6 4 8 4

8.3 12.0 20.7 4.8 8.8 11.8 2.6 4.8 4.8 6.0 6.0 2 .6 3.2 4.8 4.4

Ct

WATER of oxidants can have a synergistic effect on the in activation of Cryptosp oridium oocysts (C lancy and Fricker , 1998).

Finch et al. (1997) have fo und synergistic effects in combining oxidants for inactiva tion of oo/cysts. the C hlorination with an initial residual of 2 mg/L for 240 minutes was fo und to achieve 0 .4 log inactivation of Cryptosporidium o ocysts. O zo nation with an ini tial ozone residual of 0.7 5 mg/L for 3.7 minutes was found to achieve 1.6 log inactivatio n. However, com bining the two disinfec tants by fi rstly adding ozone, then c hlorine, resulted in 2.9 log inactivation. Other combinations were found to be more effective than the sum of the individual oxidants. Ozone wi th chloramination achieved 1.8 log inactivation; ozone and ch lorine d ioxide- 4 log; chlorin e dioxide with chlorine-2.9 log; and chlorine w ith chloramination-0.6 log. pH was also found to be importan t.

Combinati ons of oxidants w hi ch may be trialled at the WTPs include: • pre-filtratio n ozone, final ozone, chlo rine • ozone, chlorine • ozone, chlorine, UV. Ultraviolet Treatment

R ecent studies have shown ultraviolet (UV) treatment to be effective for the inactiva tion of Cryptosporidium oocysts. A full- scale system at W isconsin, USA has b een sh own in several studies to have achieved 4 log inactiva tio n of oocysts (C lancy and Fricker, 1998).

Various UV system designs exist.

More advanced UV tec hnology was fo und by C lancy e t al. to be effective in the inactiva tio n of Cryptosp oridium oocysts in filtered wate r (2 to 4 log inactivation). T his technology involves a high UV exposure, achieved by eith er high intensity pulsed UV radiation or a system in corporating screen s to retard oocysts in the region of UV radiation.

The co nve n tional thin- film UV process, wh ere water passes th ough a narrow space exposed to rays from UV lamps, was found to b e in effective in red u cing Cryptosp oridium viability (C lancy et al. ,1998).

Filtered w ater typically has a transmittance (ability to transmit UV light) of above 9 5%, which is sufficien tly greater than the 55% recom mended by UV suppliers fo r effective treatment.

Further research, how ever, into th e effectiven ess of UV as a treatm e n t option would be recommended.

R ecent feasibility studies h ave found that UV can be cost- competitive w hen compared w ith combinations of chemical disinfectants (C lancy and Fricker, 1998) .

Proprietary Filter Designs

been develop ed by th e U K - based company Kalsep Ltd to remove and inactivate Cryptosporidium oocys ts from water and wastewater. Flow is pumped through enclosed 'Fibrotex ' filter elem ents made of nylon fibres, wh ere solid s are removed and trapped.

Fibrotex is reported to achieve 98% removal of particles dow n to 2 µ m size and 99 .9% rem oval of particles 5 µ m and larger (Craft and Pearce, 1994).

Backwashing is initiated on a predetermined level of solids trapped in the filter. D uring backwashing, the fib res are twisted and untwisted in a wringing action to remove all solids. In addition to backwashing, the filter may undergo a vacuum steam pasteurisation (VSP) cycle, wh ere the filter element is sealed and steam-injected to achieve a temperature of approximately 65% C for inactivation of the oo/cysts trapped in the filter. T he Kalsep system has sa tisfactorily removed Cryptosporidium cysts from settled backwash wastewater supernatant in pilot and full scale trials in the UK (Craft and Pearce, 1994).

Sedimentation Stage in Contact/ Direct Filtration Plants

T he addition of a clarification or sedim entation stage to a contact/direct filtra tion WTP can provide increased log removal of oo/cysts during high turbidity events. This could be up to

0 .5 log during significant turbidity events. Plummer et al. (1995) fou nd 2 to 3.7 log removal of oocysts wi th bench-scale DA F, dependant on coagulant dose.

The clarification process may be used only during high turbidity events ( > 10 N TU) to improve the rem oval of Cryptosporidium and Giardia.

Land area is often a restriction for adding a clarifier to an existing plant.

Compact settling units may be the most effective options. An example of these is the Actiflo process developed an d marketed by O TV Kruger, rated at 40 to 60 m/ hr rise velocity.

Conclusions T he p otential presence of Cryptosp oridium and Giardia i n water supply catchmen ts throughout t he world crea tes a need for effective treatm ent technologies to remove the cysts· and oocysts of th ese protozoan parasites.

Optimised removal at existing water treatment plants can be achieved by use of p article counting instrume n tatio n and changes in operating procedures, as w ell as the retrofi tting of new trea tment units. N ew plants should be designed to u se particle counting and to allow for the provision of advanced treatment technologies to bette r re move cysts from the water.

SPECIALISING IN ENVIRONMENTAL SERVICES TO THE WATER INDUSTRY ...,_ Water And Wastewater Treatment & Reuse ...,_ Water Quality Management ...,_ Water Resources Development & Hydrology ...,_ Hydrogeology ...,_ Irrigation & Drainage ...,_ Industrial Liquid & Solid Waste Management ...,_ Air Pollution Control ...,_ Environmental Assessment & Management

{J;eg iS consulting Australia

CONSULTING ENVIRONMENTAL ENGINEERS & SCIENTISTS Formerly ~ Offices throughout Australia and South East Asia

One proprietary filtration system has WATER MARCH/ APRIL 1 999

15

WATER A multiple barrier approach to water treatment, which combines several treatment options to increase the overall effectiveness of the plant should be supported by effective catchment and reservoir management and reticulation cleaning and maintenance to ensure minimal risks to public health from waterborne Cryptosporidium and Giardia.

References American Water Works Association (1994) Evaluation of Ultrafiltration Membrane Pretreatment and Nanofiltration of Surface Waters, American Water Works Association Research Foundation: Denver.

AthcrholdtT, LeChavallicr M, Norton Wand Rosen) (1998) Effect of Rainfall on Gi,1rdia and Cryptosporidium, Journal A WWA, September, pp. 66-80 Bourginc F, Chapman J, Bastimcnt R, Gcnncry M and Green J (1996) The Effect of Ozonation on Particle Removal in Drinking Water Treatment. Paper presented at CIWEM branch meeting, 16 October.

Clancy J and Fricker C (1998) Control of Cryptosporidium-How Effective Is Drinking Water Treatment? WQI,July/August, pp.

37-41 Clancy J, Hargy T, Marshall M, Dykscn J (1998) UV Light Inactivation of Cryptosporidium Oocysts, jounwl A WWA, September, pp. 92-102 Craft D and Pearce G (1994) Wessex Water's Approach to the Treatment of Sand Filter Backwashings, Paper for Protozoan Parasites and Water Conference, York, UK, September.

Craft D and Pearce, G, 1994, Kalsep Technical Bulletin, 9/309.

Craig K, 1994 Bany Fair Scholarship, Overseas Study Tour, Hunter Water Corporation.

Craun G, Hubbs S, Frost F, Calderon R and Via S (1998) Waterborne Outbreaks of Cryptosporidiosis Jounw/ A WWA, September, pp. 81-91.

Dyksen J, Marshall M, Gera A and Clancy J (1998) Cost of Advanced UV for Inactivating C1yptosporidium, Journal AWWA, September, pp.103-1 l 1 Langlais B (1998) Overview of the Use of Ozone for Drinking Water, T railigaz.

Langlais B Joret JC, Pen-inc D, Chcnu JP, Lcgardinicr J (1991) Inactivation of Cryptosporidimn by Ozone. Laboratory Tests Based On A Biological Model. Tech Sci Methodes Genie Urb.1in-Gcnic Rur:1/, 4197-200 MacCormick T and Wale R (1998) Tighter Environmental Outcomes Favour Membrane Filtration, Paper for Annual Regional Conference of A WWA NSWBranch, August.

McClellan P, 1998 Sydney Water Inquiry, 1st, 2nd and 3rd Interim Reports, New South Wales Government,.

Muntisov Mand Trimboli P (1996) Removal of Algal Toxins Using Membrane Technology, Water, March/April, 21.

Murray BA (1994) The Application of Particle Counting to Water Treatment in Austrnli,1, City Water Technology/ Pacific Dynamics, July.

Murray B A ( 1995) Particle Counting in Water Treatment. Water 22, 2 May/] unc NHMRC/ARMCANZ (1994) Draft Australian Drinking Water Guidelines.

Rositano J and Nicholson B C (1994) Water Treatment Techniques for the Removal of Cyanobacterial Toxins from Water, Australian Centre for Water Treatment and Water Quality Research, Salisbury, South Australia.

Sydney Water Board (1993) Prospect Prototype Plant Research and Development Project Report, May.

Authors Bruce Murray has 17 years experience in water and wastewater treatment. He is a founding director of City Water Technology Pty Ltd, 2/5 St Johns Ave Gordon NSW 2072, email: water@rivernet.com.au Kirsten Linnemann is an environmental/process engineer with City Water Technology. Keith Craig has twenty years of experience in water treatment investigation, design and operations. He is Technical Director ofCGE Australia, Level 37, Gateway, 1 Macquarie Place, Sydney 2000, email: kcraig@cgeaustralia.com.au.

16

WATER MARCH/APRIL 1999

Waste Disposal: Water, Sewage, Refuse and Recycling.

4-8 May 1999 New Munich Trade Fair Centre

Information:

m

WATER

BIOAVAILABILITY OF ALUMINIUM IN ALUM-TREATED DRINKING WATER AND FOOD J L Stauber, C M Davies, M S Adams, S J Buchanan, T M Florence Abstract

(ATW) were to contribute significantly to the incidence of Alzheimer's disease,

males and 8 females, rangmg in age from 36- 76 years) were selected after pre- screening that included a personal medical history questionnaire, a limi ted physical examination, analysis of urine for traces of blood, glucose and protein, haematological screening of blood, dete rmination of plasma alu minium, and calculation of creatinine clearance rate as an indication of efficiency of kidney function.

T he role of dietary aluminium in the bioavailability of aluminium, i.e. its Alzheimer's disiease remains controveruptake fro m the gut into the bloodsial. Several epidemiological strudies have implicated alum-treated drinking stream, would have to be much higher wa ter despite the fact that the from water than from food, because aluminium in the water would provide water represents only a minor fraction a relatively minor proportion of the (1 - 10% ) of the daily inta ke of normal daily intake from the diet. It has aluminium (Gardner and Gunn, 1995; been postulated that such alumini um Cumming, 1996). Despite rece n t may be more bioavailable than that in research suggesting that aluminium in food, particularly if food acids such as food and water has similar bioavailabili- General Analytical Procedures ties (Priest et al., 1995) , there is contincitrate are also ingested.

All analytical procedures, including This paper summari ses a research uing concern that aluminium in ATW blood collection, were carried out in a project which measured accurately the is present in more labile forms and is Class-100 clean room. Glasswa re and daily aluminium balances in a cohort of therefore more bioavailable. plasticware were soaked in 10% (v/v) Because of the analytical problems 29 healthy volun teers drinking, over ni tric acid (AR) for at least 24 hours. two- day periods, alum- treated water or associated w ith measuring the low Polycarbonate vials (30 mL) used for pure water, with and w ithout citrate , amounts of aluminium in blood and plasma co!Jection were soaked in Extran urine, previous attempts to measure the whilst on a controlled diet.

300 detergent overnight, followed by It was found that there was no signif- relative bioavailabilities of aluminium 10% (v/v) nitric acid . All acids used icant difference between the bioavail- from water and food have involved were Suprapur grade and only high ability of aluminium in water and food, adding aluminium, usually as a radio- purity M illi-Q water was used throughwith or w ithout citrate. After d rinking tracer, to the food or water (Priest et al. , out the experiments. alum-treated water, the extra ingested 1996). However, this added aluminium aluminium was excreted in the urine. It may not equilibrate with the aluminium Axial Inductively Coupled Plasma was estimated that d rinking 1.6 L/d of already present in water or food. In the Atomic Emission Spectroscopy • water containing 140 mg Al/L would present study, the relative bioavail- (ICPAES) Aluminium in food, water, blood contribu te only 0.4- 1.1 % of t he abilites of aluminium in food and ATW were dete rmined by m easu ring plasma and urine was determined using lifetime body burden of aluminium. aluminium uptake into blood plasma ICPAES (Spectroflame EOP IC PAES). and excretion in the urine of29 healthy On and off peak (0.0 15 nm below) Introduction Epidemiological stu dies in towns volunteers, ranging in age from 36-76 measu rements were done at five where the wate r supply had been years. Using the sensitive technique of seconds each on alu minium (167.08 treated by flocculation w ith aluminium axial inductively coupled plasma atomic line) and iron (259. 94 line) simultanesulphate (alum) have produced conflict- emissio n spectroscopy (ICPAES) , the o usly. A ll glassware, nebuliser and ing results (Martyn et al. , 1989; uptake of natural aluminium in the diet peristaltic pu mp tubing were new and Giorda no and Costantini, 1993; was measured . No aluminium was used only for this study. Before each Nieboer et al., 1995; Martyn et al., added to the food, nor was any experiment the end- on- plasma inter1997). The chemical fo rm of additional alumini u m added to the face was thoroughly cleaned. T h e alumi nium in drinking water may be a ATW. To avoid variations in urinary instrumen t was initially fl ushed for one crucial variable in explaining t he aluminium excretion, the volunteers' hour with 2% reagent grade nitric acid conflicting epidemiological evidence diets were strictly controlled through- followed by a 100 ¾g Al/L solution to (Harris et al., 1996). Fluoride, pH , out each 48- hour study period. profile the polychromator. A new fl ush silicon, iron and natural metal chelating Methods solution of 0.5% NaCl and 4% nitric agents in the water may all in fluence the acid was aspirated for at least one hour speciation of aluminium and conse- Volunteer Recruitment and and Milli- Q water was scanned to Medical Pre-screening quently its bioavailability and toxicity. ensure no aluminium contamination If alum- treated drinking water T wenty- nine healthy volunteers (21 was p resent.

WATER M ARCH/APRIL 1999

17

WATER To determine iron interference at the aluminium line, 0.9% NaCl with 0.4 M HC1O 4 was measured, followed by the solution spiked with iron (5 mg/L), and the n another solution spiked with aluminium (20 µ g/L).

These were used for iron and aluminium correction for all plasma samples. As iron con centrations in all urine samples were low, no iron correction was required. Each urine sample was also spiked with 200 µg Al/L and analysed for matrix correction.

Drinking Water The volunteers were given 1.6 L/day of either reconstituted synthetic softwater (RSW) or A TW from a municipal treatment plant (Grahamstown, NSW).

The 200 L of ATW was stored in plastic containers at 4° C prior to use. The mean pH of the ATW was 7.0 and the fluoride concentration was 0.27 mg/L. Total aluminium in ATW was determined immediately prior to each experiment. Labile aluminium was also determined prior to each experiment using a modified method of LaZerte (1984). Chloroform was used in place of methyl isobutyl ketone, and aluminium was determined by ICPAES after back extraction into 1 M HCI. RSW was prepared con ta111111g 0.480 g of NaHCO 3 , 0.300 g o f CaSO 4 .2H2O, 0.300 g of MgSO 4 and 0.020 g ofKCl in 10 L. Care was taken to e nsure that the total aluminium concentration in the R SW did not exceed 1 µ g/L. Food Volunteers were given a controlled die t (prep ared 111 stainless steel cookware) cons1st111g of weighed amounts of meat, vegetables, pasta, cereal, bread, fruit and tea. Each component of the diet was analysed for aluminium, after microwave- assisted acid digestion, so that the exact intake of aluminium from food was known fo r each volunteer. Sufficient meals were prepared in one batch for the entire study, and frozen in individual portions.

Aluminium in Plasma Great care was taken during the blood collection and analysis to prevent contamination. Blood was collected in sodium heparin (trace element free) Preliminary experiments tubes. confirmed that only these tubes had sufficiently low (<0. 1 µg Al/L) and reproducible background aluminium concentrations w hen filled with 0.9% NaCl. Plasma was separated by centrifugation immediately after blood collection and deproteinized with the addition of0.4 M HC1O4 • Blanks were prepared by filling four sodium heparin tubes with 0.9% Suprapur NaCl and processed as for the plasma.

18

WATER MARCH/ APRIL 1999

Detem1ination of aluminium in plasma was carried out in duplicate, using separate tubes of blood collected from each volunteer. To determine the accuracy of the method, Seronorm reference serum (Nycomed, Oslo, Norway) spiked with 61 µg Al/L was processed and analysed as for plasma.

Aluminium in Urine Urine was collected over 24 h ours.

Prior to the start of collection the volu nteers emptied their bladders. To minimise aluminium contamination, as much clothing as possible was removed before urine collection. The volume of each 24-hour unne sample was measured and the samples were stored at 4° C without pre-treatment until analysis. Aluminium was de termined directly on these samples. To determine the accuracy of the method, Seronorm reference urine (Nycomed) spiked with 161 µ g Al/L was also analysed.

Creatinine in urine was de termined using a diagnostic kit (555-A , Sigma Chemical Co., St. Louis, MO, USA).

drank a total of 1.6 L of ATW (or RSW) over the second day. Urine samples were collected from 8 am on the second day until 8 am the following day.

Sufficient time between each experiment (1 -4 weeks) ensured that there was no carry- over of effects from one experiment to the next, and it was assumed that the order of the experiments had no effect on the results.

Statistical Analyses The plasma and urine data were analysed using the statistical software package Genstat™ R elease 3.2. For the urine data, analysis of cova rian ce (ANCOVA), with age as the covariate, was used to determine w hether there was a significant increase in aluminium after drinking A TW and whether any increase was related to the sex or age of the volunteers. Students' t-tests were also used to determine significant differences 111 plasma aluminium concentrations 111 each individual between samples collected before and after ingestion of food and ATW.

Aluminium Bioavailability Experiments Results and Discussion A crossover experimental design was used with the treatments having a facto- Preliminary Analytical rial structure, i.e . ATW (present, Experiments absent) and citrate (present, absent). In Aluminium in Water and Food. The Experiment 1, the uptake of aluminium ATW contained 140 ± 9 µ g Al/L, of from food plus ATW was determined. which 97 ± 2 µ g/L (75%) in In Experiment 2, RSW was substituted Experiment 1, and 88 ± 8 µg/L (61 %) in for ATW and the uptake of aluminium Experiment 3 was chemically labile. from food alone was determined. In This labile fraction or 'fast reactive' Experiment 3, citrate was added to the alu minium would include hydrated A TW to give a total daily dose of 60 mL monomeric aluminium species and of 10% potassium citrate, equivalent to inorganic aluminium complexes which about 350 mL of orange juice. U ptake would be potentially bioavailable. The of aluminium from food and A TW plus non-labile fraction would include some citrate was determined. In Experiment orga nic aluminium complexes, 4, RSW was substituted fo r ATW, and polymeric inorganic complexes, and the same amou nt of citrate was added to possibly aluminium associated w ith the RSW to be taken with the standard colloidal day particles. Part of this nonmeals. labi le fraction, particula rly the Each volunteer participated in four p olymeric inorganic aluminium, may different experiments, each over two also be potentially bioavailable. days. The first day of each exp eriment The RSW co ntained 0.2- 0.6 µ g consisted of a standard diet (no A TW) Al/L. Aluminium in the 10% potassium to stabilise the volunteers' urine and citrate stock solutions made up in RSW blood, during which no urine or blood and in ATW was 29 and 158 µ g Al/ L, samples were collected. The second day respectively. involved the same diet including A TW Total aluminium concentrations in or RSW (with or without citrate) all food eaten by the volunteers over the together with blood and urine collec- study period are shown in Table 1 and tions. Prior to drinking A TW (o r in Figure 1 The standard meal RSW), a fasting blood sample was collected at 8 am on the second day.

1.60 Volu nteers then drank ci 1.20 ATW (or RSW) and ate a ::,. standard prepared break0.80 <i: fast (including one cup of 0 .40 tea). Two hours after 0.00 drinking ATW (or RSW), Meal Weet-Bix Tea M Iik Sugar Biscuil Banana a second blood sample was collected.

Vol untee rs Figure 1 Aluminium content of food

""

WATER bread, cereals, pasta, meat and vegetables (Cumming, 1996). Insta n t tea contained high concentrations of aluminium (445 µ g per 250 mL cup) but this was less than reported for brewed 0.70 tea whic h typically 0.60 contains 208 mg Al/L depending on the ::; 0.50 ch type o f tea and .2: 0.40 infusion conditions ;j: 0.30 (Flaten and Odegard, "' E 1988). Only 15% of 0.20 "' 1i: the total aluminium 0. 10 in the tea was chemi0.00 cally-labile, in agreeFood+ Food only ATW + Citrate ATW ment w ith reports that over 90% of Figure 2 Aluminium concentration in plasma aluminium in tea is present as high molec6.00 ular weight organic complexes and that 5.00 the bioavailability of ...2~ 4.00 aluminium from tea is < low ( Gardner and "'::i.

-; 3.00 Gun n, 1995) . .;

contained 1.36 ± 0.05 µg Al/g (4 replicate samples) or about 730 µg Al per 542 g meal. This was w ithin the reported range of200-8,000 µg Al/kg in

(/)

0:

§ 2.00

Alumlnlum In Blood Plasma. The detec-

~

!;l w 1.00

<i: 0.00

ATW

Food+ Citrate

ATW+ Citrate

Food Only

• Mean • Males • Females

tion limit for aluminium in plasma was 0.15 µg Al/L (3 x standard deviation of the blank). The preci-

Figure 3 Aluminium excretion in urine Table 1 Aluminium content of food and water Approx. Al content per serve, µg AL (µ&fg) ± ISD 2 •

Sample

Standard meal Breakfast cereal (Weet-bix) Full cream milk (200ml) Skim milk (200ml) Skim milk sachet (200ml) Instant tea (250ml) Sugar (3.5g) Biscuit (18g) Banana (200g) Alum-treated water Reconstituted soft water • One standard deviation b

1.36 + 0.05 1.39 ± 0.12 0.10 ± 0.08 0.06± 0.06 0.03 ± 0 1.78 ± 0.04 0.05 ±0.03 0.71 ± 0.06 0.01 ± 0.04 140 ± gb 0.4 + 0.2b

730 43 20 12 0.6 445 0.18 13 2

-

µg/L

Table 2 Mean bioavai labilities of alu minium from the diet and ATW based on urinary excretion data Experiment

Mean Al bioavailability (%) Total diet (food+ tea+ ATW)

Food+ tea

0.29 Experiment 1 (with ATW) 0.538 0.29 Experiment 2 (0 .28 - 0.64)6 (No ATW) 0.29 Experiment 3 (with ATW + citrate) 0.53 4 0 .26 Experiment 4 (0.28 - 0.64)b (with citrate, no ATW) • Assuming that 15% of aluminium in tea (the chemically labile fraction) is available for uptake b Range of values assuming that 0- 100% of alumimium in tea is available for uptake

ATW 0.39

0.36

-

sion of the analyses at the 0.5 µ g Al/ L level was such that increases of 0.3 µg Al/Lin plasma would be detectable and significant at p<0.05. A value of 59 µg Al/L was obtained for the certified reference plasma containing 61 µg Al/L indicating excellent accuracy.

Alumlnlum In Urine. The detection limit for aluminium in urine was 0.08 µ g Al/L (3 x standard deviation of the blank) , with a precision of 2% (2 standard deviations) at 2 µg/L. When 2 µg Al/L spikes were added to a urine sample, the recovery (2 standard deviations) was 1.92 ± 0 .09 µg/L. A value of 155 µg Al/L was obtained for the certified reference urine containing 161 µg Al/L indicating excellent accuracy.

The superior detection limits and precision obtained fo r aluminium in blood plasma and urine are primarily the result of using the highly sen sitive Spectroflame axial ICPAES instrument.

Alumlnlum Bloavallablllty Experl· ments. Average total intake of

aluminium from food, tea and water for the volunteers was 3,200 µ g Al/day.

Food (in cluding tea) contributed approximately 3,000 µg Al/day to the diet. Of this, tea contributed 1,700 µg Al/day. Aluminium from the ATW contributed 208 µ g (Experiment 1) and 233 µg (Experiment 3). Aluminium from the synthetic softwater was less than 1 µg/day.

Total aluminium in blood plasma ranged from 0 .24-1.25 µg Al/L, with a mean of0.47 ± 0.12 µg Al/L (see Figure 2). Many previous studies have reported erroneously high values, due to contamination during blood collection and sample analysis, or due to insensitivity of the analytical method used.

Values of 0.5-4 µg Al/L serum, with means of 1.0-1.6 µ g Al/L in nonoccupationally exposed subjects have been reported (Wang et al., 1991; Lee et al.,1996; Valkonen and Aitio, 1997).

There were no significant differences in mean plasma aluminium concentrations between volunteers of different ages or gender (p>0.05).

Total aluminium in urine ranged from 0.68-6.02 µ g/ L, generally lower than values reported previously (2. 7- 8 µg /L, Nieboer et al. , 1995). Daily excretion rates ranged from 1.8-9.3 µg Al/24 h, similar to the normal range of 4-12 µg Al/24 h (Nieboer et al., 1995) (see Figure 3). There was no correlation between urinary aluminium excretion rates and renal function (creatinine clearance rates) .

No increase in aluminium in blood plasma of the volunteers was detectable after drinking A TW, with or w ithout citrate (p>0 .05). H owever, due to the lower detection limit for aluminium in urine and greater statistical power (84%), a significant increase of 9% WATER MARCH/APRIL 1999

19

WATER alumi ni um excretion rates than females.

0.5 However, this finding ~ e..., should be interpreted 0.4 g with cau ti on du e to 15 0.3 small number of the .!!! .iij females participating in > 0.2 <ti 0 the study. ai 0. 1 C itrate had n o <( effect (p>0.05) on the 0 uptake of alu minium ATW F ood Only ATW + Food+ from either ATW or • To t al Diet • Food+ T ea Cit rate Citrate food. It appears that . ATW alumi nium naturally Figure 4 Mean aluminium bioa vai lability: percentage of intake prese nt in food or in t he A TW 1s not (p <0.01) in the daily exc retio n o f made more bioavailable w hen citrate is aluminium in uri ne was fo und. An added. increase was expected because the total Alu minium bio- availabili ty from alu minium intake in Exp eriments 1 and food or water was calculated using the 3 (with ATW) was higher. ATW following equation: contributed 6-7% of the dietary intake of aluminium, which was similar to the Al bioavailabilicy (%) = (Al excretion in urine 0.6

observed increase of 9% in the excretio n of aluminium when ATW was consumed.

The increase in urinary excretion of al uminiu m after the ingestion of ATW w as a general trend among all volunteers and was not due to sp ecific individuals who had more variable urinary excretio n values. The age of the volun teers had no effec t on aluminium excretion.

M ales had significan tly highe r

(µg Al/24) x 2.2 x lOO)/ Al intake (µg)

in w hich a correction fac tor of 2.2 (Pri est et al. , 1996) is used to correct fo r incomplete urinary excretion of absorbed aluminium over 24 hours.

The bioavailabilities of aluminium from water and food are shown in Table 2 The mean bioavailability of alu mini um from ATW was 0.37% , compared to 0.28% from food plus tea.

However, if the low chemical !ability of

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aluminium in tea (15%) is taken into account, the bioavailability of aluminium from food alone could be as high as 0.6%. Thus the bioavailabili ties of aluminium from food and ATW were similar, suggesting that aluminiu m from drinking water is not uniquely bioavailable and therefore unlikely to contribute to t he incide nce of Alzheimer's d isease.

Assuming an ad ult human body burden of 30 mg Al, we calculated that the A TW used in this study (140 µg Al/L) would contribute only 0.4-1.1 % of the lifetime body burden of aluminium. When a diet contains mo re than the 3 mg Al/day used in this study, the co ntribu tion of ATW to body burden of aluminium wou ld be even lower. This rep resen ts a rela tive ly minor component of the total intake of aluminium in h u mans (Cumming, 1996).

Conclusions Preliminary experiments confirmed t hat axial IC PAES was suitab le for determining co n centrations of aluminium in urine and plasma at the sub-ppb level. The limits of detection for alu minium in urine and plasma we re 0.08 and 0.1 5 µ g Al/L, respectively.

In general, there was no detectable increase in aluminium in blood plasma after drinking ATW (with or withou t citrate).

There was an increase in urinary excretion of aluminium after drinking ATW. The bioavailability of alumi ni um from food plus tea ranged from 0.28- 0.64%, depending on the estimated bioavailability of alu minium in tea. The bioavailability of aluminium from ATW, calc ulated from the urinary excretion data , was 0 .37% of the total aluminium in ATW or 0.56% of the chemically labile aluminium in ATW. The bioavailabilities of aluminium from food and A TW we re therefore similar.

Note that this conclusion applies to healthy volunteers with normal renal fu nction and may not necessarily apply to people with impaired renal function or gastrointestinal problems.

The presence of citrate in the ATW did not increase the uptake or exc retion of aluminium in urine.

The age of the volunteers had no effect on aluminium excretion.

It was estimated that drinking 1. 6 L/day of ATW containing 140 µg Al/L would con tribute only 0.4- 1.1 % of the lifetime body burden of aluminium.

Due to the high statistical p ower (84%), the 24-hour urine collection was preferab le to plasma collection for accurately determining the bioavailability of aluminium from the diet.

WATER AEA Technology Harwell Laboratories Aluminium in Waters. Annual 1st Super Report AEA-TPD- 269, UK. pp. 1-25.

Sanita 29, pp. 305-311.

Harris WR, Berthon G, Day JP, Exley C, Priest ND, Talbot RJ, Austin] G, Day JP, King S J , Fifield K, and Cresswell R G. Flaten T P, Forbes W F, Kiss T, Orivig (1996) The Bioavailability of 26AlC , and Zatta P F (1996) Speciation of labelled Aluminium Citrate and Aluminium in Biological Systems. ].

Aluminium Hydroxide in Volunteers.

Toxicol. Environ. Health 48 , pp. 543Biometals 9, pp. 221 -228.

568.

LaZerte B D (1984) Forms of Aqueous Valkonen S, and Aitio A (1997) Analysis of Aluminium in Serum and Urine for the Aluminium in Acidified Catchments of Biomonitoring of Occupational Central Ontario: A Methodological Exposure. Sci. Total Environ . 199, Analysis. Can. ]. Fisheries Aquatic Sci. pp.1 03-110.

41 , pp. 766-776.

Lee B-L, Chua L-H, Ong H-Y, Yang H Wang S T, Pizzolato S, and Demshar H P (1991) Aluminium Levels in Normal G, W u J, and Ong C -N (1996) Human Serum and Urine as Determined Determination of Serum and Urinary

by Zeeman Atomic Absorption Aluminium by HPLC with Fluorometric Spectrometry.]. Anal. Toxicol. 15, pp. detection of Al-lumogallion Complex.

66-70.

Clin. Chem. 42, pp. 1405-1411.

Martyn C N, Barker D J P , Oxmond C, Authors Harris E C, Edwardson J A, and Lacey R Dr Jenny Stauber is a Principal F (1989) Geographical Relation Between Research Scientist and leader of the Alzheimer's Disease and Aluminium in Environmental T oxicology Group, Drinking Water. Lancet 14, pp. 59-62.

References CSIRO Division of Energy Cumming F J (1996) Biological Aspects of Martyn C N, Coggon D N, Inskip H , Lacey Technology, Lucas H eights, specialisRF, and Young W F (1997) Aluminium Aluminium in the Food and Water Concentrations in Drinking Water and ing in the development of techniques Supply. Report No. 201. Water Services Risk of Alzheimer's Disease. for assessing toxicity of metals in both of Australia.

Environmetrics 6, pp. 233-275. humans and aquatic systems. Email: Flaten T P, and Odegard M (1988) Tea, N ieboer E, Gibson B L, Oxman AD, and jenny.stauber@det.csiro .au. Dr Cheryl Aluminium and Alzheimer's Disease.

Kramer J R (1995) H ealth Effects of Davies is a microbiologist and Merrln Food. Chem. Toxicol. 26, pp. 956-960.

Aluminium: A Critical Review with Gardner M J , and Gunn A M (1995) Adams and John Buchanan are Emphasis on Aluminium in Drinking Speciation and Bioavailability of analytical chemists with CSIRO, Lucas Water. Environ. Rev. 3, pp. 29- 81.

Aluminium in Drinking Water. Chem.

H eights. Dr Mark Florence is Director Priest ND, Talbot RJ, and Austin ] G (1995) Spec. Bioavail. 7, pp. 9-16.

The Bioavailability in Young Adults of of the Centre for Environmental and Giordano R, and Costantini S (1993) Some H ealth Science, Sydney.

Aluminium Ingested in Drinking Water.

Aspects Related to th e Presence of

Acknowledgements This project was funded by the Water Services Association of Australia.

We would like to thank Bob Dorrat (Project Manager, WSAA), Hunte r Water, Bronwyn H arch and Ray Correll (CSIRO Mathematical and Information Sciences), Barry Evans (Advanced Food Systems), Graeme Kearns and Dr Armand Casolin (Health Services Australia), Kim Beekma (Hampsons Pathology), Dr Ian Macmillan and Terrie Smith (ANSTO), and for technical assistance, M ichelle Pham, Sherry Yuen and Michael Crema (CSIRO). Most of all we would like to thank the 29 volunteers from Engadine Probus Club, and from the CSIRO and ANSTO staff at Lucas Heights.

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WATER

November 1998, a major Asian conference came to Sydney (and to Australia) for the first time. This was a conference held by the ASPAC (AsiaPacific) group of the International Water Services Association (IWSA).

Being the 11 th biennial conference held by the ASPAC group, the conference has been held in many major Asian capitals up to now. Wi th over 400 delegates from more than 40 countries, this was certainly a meeting of a major cross- section of the world's wate r players. As the IWSA is in the process of merging with its sister o rganisa ti on, IAWQ (International Association on Water Quality), the Sydney event may well have been the last to take place before the melding occurs.

Entitled Integrating the Urban Water Cycle, the conference was strongly urban in its focus; and it had almost as strong a foc us on drinking water. Mindful of the pending me rger, tho ugh, organi sers Australian Water and W as tewater Association (AWWA), had made an effort to acknowledge the o rganisational and functional integration that is now so prevalent, and there were many papers on issues su ch as wa ter reuse and catchme nt managem ent. There was also a recycling seminar under way in the same venue, so delegates were able to partake of a great deal of recycling informa tion.

The host hotels, Landmark Parkroyal and R ex, are located in the colourful and some times raffish Kings C ross precinct, outside Sydney's downtown area, but close enough for convenience

ASPAC Conference Chairman Richard Marks hands over the reins this year to Mme Chuanplt Dhamaslrl from Thailand

to transport and the city's other amenities. D espite some threatening weather, co nditions we re ge nerally good and delegates walked to and fro between the hotels and enjoyed the various off- si te social events and the technical tours.

Apart from bringing together urban water practitioners from around Asia and the Pacific, the event also served as host to the Gove rning Board and Scie n tific and T echnical Council of IWSA itself, so around 70 of the world's water utility leaders gathered for those meetings just before the conference.

Several stayed on to attend ASPAC and added their weight to n um bers and experience.

In a friendly welcoming fu nction, held in histo ric R ockwall House, delegates mingled wi th a traditional Australian bush band, a soldier resplendent in his red coat and tall hat, a cartoo nist in colonial dress and a thoroughly d isreputable looki ng ch aracter who ended up maki ng little balloon sc ulp tures for some of his Conference o rga msm g victi ms.

C hai rman Richard M arks made a short welcoming speech in the garden behind Rockwall House-a sudden , sharp shower of rain ensured that it was very short.

D elegates were ente rtained at the opening ceremony by Naroo, a team of Aboriginal dancers and m usicians, performing appropria tely watery themes. As always, the eerie sou nd of the didgeridoo sent shivers down the spines of visi tors and locals alike. New South Wales Governor, t he Hon Gordon Samuels AC, officiated at the openi ng, after the dancing, and added gravi tas to t he occasion, as well as commenting widely on trends in the water industry.

After the Governor, N icholas Hood, CBE, Chairman of Wessex Water in England, and President ofIWSA, delive red a wide- rangi ng keynote address.

H e pain ted a picture of some gloom (overpopulation and resulting pressures o n water) and some light (the ability of companies to deliver infrastru cture cost- effec tively) for a world which

A wetland to pollsh stormwater at Homebush Bay, New South Wales

WATER MARCH/APRIL 1999

23

WATER continues to get smaller from a communications point of view. He concluded by suggesting that the new, merged IWA should be capable of playing a leading role in keeping nation al leaders foc used on the task of ensuring that the desperately needed infrastructure does, in fact, get installed.

Dr Richard Helmer, C hief, Urban Environment H ealth , with the World H ealth Organisation (WHO), was next up to tell delegates how critical the microbiological quality of water still is for most of the world. This is especially so for the developing and least-developed nations. Dr H elmer said that chemical contamination is slightly less critical but still poses risks. The puzzle for administrators and regulators is to balance expected health benefits against the cost of the range of possible interventions. H e concluded by suggesting that the W HO guidelines for microbiological quality of wa ter could be viewed as a target or 'challenge,' to be me t by a combination of auditing processes and measuring achieved water quality.

Dr Jim Gill, M anaging Director of the W ate r Co rporation in Weste rn Australia and C hairman of the W ater Services Association of Australia, threw down the gauntlet in his keynote speech. H e recou nted the recent history of private sector participation in water in Australia and internationally, which has mostly been dominated by English and French companies. H e explained that national cultural fac tors and tax laws affect the way companies will invest, so nominally 'level playing fields' are, in practice, steeply tilted. H e challenged Australian water enterprises to ge t together and create a viable competitor to the world players, capable of winning in the face of global competition.

After the keynote speakers, the conference split into a n umber of stream s to tackle topics in more detail.

The major stream s related t o: n ew techniques in treatmen t, regulatio n , p rivatisation, growth, problem waters, research, leakage, dema n d manage1nent, reuse, storage, catc hme nt manage m ent, integration, health, rehabilitation of systems, and more. In an overview article of this scope, it is not possible to do j ustice to the full breadth of papers, so selected highlights have been extracted and are reported here.

Rozali Ismail , of Puncak N iaga Sdn Bhd, M alaysia, gave an overall view of the history and status of private sector participation in the M alaysian water industry, which has been evolving actively since government policy shifted towards PSP in 1983. H e explained how the large capital requirements 24

WATER MARCH/ APRIL 1999

ment plants drawing water from rivers w ithou t bankside (off-river) sto rage subject to an operational standard of not more than 1 oocyst per 10 L, based on daily composite samples of 1,000 L. From the problematic area of parasites, speakers turned to operation and maintenance of the massive pipe networks involved in urban water systems. R obert Ius in a paper delivered

by D Mirkovic, described an integrated instrumentation, control, automation and tel emetry (IICATS) system fo r water supplies. Successful implementation was only possible thanks to a parallel evolution of an integrated manageDr Richard Helmer from WHO ment system for the people involved. delivering his keyn9te address Jian Ping Wang told delegates about a effectively create barriers to entry for similar distributed intelligent managecompanies in the p rivate water business. ment system fo r the wate r supply of He advocated the adoption of the latest Guangzhou in C hina. This system has technology to deal with the challenges an expert system built into it to develop facing wate r quality, quoting as an heuristics for decision making, based on example the use of a real- time river the evolving history of the system . For monitoring system to provide advance Hong Kong, Lam and others reported warning of pollu tion incidents. on the installation of a geographic inforBing-Mu H su and colleagues mation system (GIS) and automated presented data on the occurrence of mapping-facili ties management Giardia and Cryptosporidium in raw (AM/ FM) for th e Water Supplies water in T aiwa n . They fou nd Department, which serves 6.5 million Cryptosporidium in 60% of samples people. T he G IS, AM/ FM system is to and Giardia in 35% . The paper led to be the main plank in future asset controversy in the conference, as other management systems. delegates sp rang to the defence of water Reflecting growing inte rest in reuse, quality in Taiwan . Clearly, though, the several authors addressed th at topic, relatively high rates of occurrence of from different perspectives. William protozoan parasites is not inconsistent Lim and Ngin See Lim described with experiences in othe r cou ntries. Singapore's approac h to ha rvesti ng Magara and others from J apan reported urban stormwater for potable use, a on a somewhat larger survey in Japan practice in operation there since 1986. which fou nd C1yptosporidium in 8% of Although initial stormwater harvesting raw water samples and Giardia in 24%. facilities were fu nctional, later versions Michael Rou se desc ribed Crypto- have become more aesthetic in the ir sporidium as the 'cu rrent most serious layou t, or have been cu nningly placed waterborne risk to public health in the under highway flyovers or below public UK. ' H e outlined regulations that have open space. Designing these facilities been mooted which would see treat- pose special challenges, because

WATER Singapore's rainfall is characterised by short, sharp storms that move across the island. Tatsuo Shimizu and colleagues reported on research in Sapporo, Japan, which showed chat applying iron salt coagulation to a mixture of river water and t reated sewage effluent, then sto ring that water in Lake Barato, allowed natural purification in the lake to bring water quality up to a standard good enough for non-potable reuse.

Richard Marks and colleagues delivered a paper on the use of treated effluent from the major Boliva r plant in Adelaide, South Australia, to irrigate market gardens in Virginia, north of the city. The first stage of a scheme to treat 60ML/d of effluent pe r day , by dissolved air flotatio n and filtration, was due to be commissioned in late 1998.

Ac the other end of the size scale, Prof Geoff O'Loughlin and colleagues reported on 18 months of data from an integrated domestic water system in a small hou se in inner Sydney. T he au thors concluded chat in Sydney it is feasible to provide a family of four with potable water from rainwater (collected from the roof of the house) most of the time, and to treat and partially reuse sewage. Within the 18-month period, mains water had co be u sed four times, owing to the restricted space ava ilable for storing collected rainwater. There are aJso some questions surrounding the long-term salt balance where effluent is irrigated, but th e owners of the house, Michael Mobbs and Heather Armstrong, expressed satisfaction with the system overall.

Several authors addressed the qu estion of drinking water standards and gui de lines in the UK, USA, T aiwan, Slovakia and Australia. Each country tended to have its own unique sec of priorities, but each faces the issue o f estimating hazards, public health

benefits and the puzzle of striking maximum contaminant levels that will balance those issues. Dr J enny Stauber, from the CSIRO in Australia, presented interesting results from a study of the bioavailability of aluminium in drinking water, showing that no increase in aluminium in blood plasma was caused by drinking ATW (alum- treated water) containing 140 micrograms of Al per litre (see her paper in this issue of Water). On the other hand, a significant increase in urinary aluminium was detected, confirming chat the aluminium was effectively excreted. Dr Stauber concluded that drinking 1.6L/d of ATW containing 140 micrograms AJ per litre would contribute only 0.4%-1.1 % of the lifetime body burde n of aluminium from the diet.

Of course, given the nature of the conference, many authors delved into the detail of water treatment. Their topics included ac tivated ca rbo n , ozonation, membranes and desalination, as well as softening and more. The overall picture seemed to be that the condition of water in various cities, coupled with local technical and operating resources, makes fo r a wide variety of optio ns and optimal solutions to water treatment. Clearly, catchment management, water treatme nt and sewage treatment are now see n as closely inter-related, whereas they would have been treated as separate topics in the past. A particular example is the impact of organic material on treatment, a factor that was previously not closely stu died, but which has profound impacts on performance of coagulation.

Unaccounted for wate r (mostly leakage) remains a demon fo r most water supplies. Several authors reported on their work and the figures for losses

ranged from a low of 5% for Nagoya (which had peaked at 80% immediately after World War II bombing) to a high of 40% in Sao Paulo. Strategies to m11111nise Josses include pressure control, public education, leak eradication, modelling and monitoring.

The round-up given above can only be a sample of the more than 90 papers presented at the conference. Discussion was lively and there was ah,vays a buzz among delegates, moving from session to session or j ust net\;vorking or inspecting the trade displays.

The conference had its fair share of social activi ties too, with an optional dinner at Sydney's most renown ed C hinese restaurant and the official conference dinner at a seafood restau rant overlooking the beautiful Sydney Harbour. A tradition at ASPAC conference dinners was maintained, as each cou ntry sent its delegation to the stage to perform a traditional song. le was not easy to squeeze 80 J apanese delegates up there, so a smaller team was sent up, includ ing a magician . Korea supplied C\,\lo brave singers, while the Europeans co m bined forces to field a strong chorus. Conference Chai rman Richard Marks had obviously been preparing for the event; he produced his piano accordion and led the strong Austral ian contingent in song.

At the closing ceremony, ASPAC Chairman Richard Marks handed over his chain of office to Madame C huanpit D hamasiri from from the Metropolitan Waterworks Auth ority in Bangkok.

Mme C huanpit will hold office fo r C\,\lo years, culminating in the 12th ASPAC Regional Conference, to be held in Chiangmai from 10 November 2000.

Delegates who stayed on joined technical tours co the highlights of Sydney's water system on the lase day.

T hey visited Warragamba Dam, the Prospect Water Filtration Plant, Quakers Hill Sewage Treatment Plant and Sydney Water's cen tral IICATS centre, which controls the whole water system.

Thanks to the strong support from delegates, authors and key sponsors (Sydney Wate r, Australian Water Servi ces and t he Water Services Association), the 12th ASP AC Conference was successful and seemed to build good bridges bet\,\leen practitioners and cou ntries in the region.

T hailand in 2000 wi ll continue the tradition and prom ises to bring the region's water industry up to date once more, but this time under the banner of the new In te rnational Water Association.

Chris Davis is Executive Director of

AWWA. WATER MARCH/APRIL 1999

25

m

WASTEWATER

¡

GROUNDWATER CONTAMINATION FROM EFFLUENT IRRIGATION V O Snow, P J Dillon, W J Bond, C J Smith, B J Myers Abstract Al though 1rngation of efflu ent protects surface water from direct nutrient loads, it can adversely affect groundwater quality if t he system is not designed and operated appropriately.

The risk of contaminating groundwater with nitrate can be reduced by matching the plant production system to the climate at the eilluent-i rrigation site.

The model APSIM was used to examine the relationships between plant production system , climate, eilluent characteristics, and groundwater contamination.

The simulation results demonstrated that in climates that have high rainfall, resulting in less irrigation and more drainage, the amo unt of nitrogen harvested from a well managed tree plantation might be sufficient to protect groundwater quality. In these climates, there may be a substantial amou nt of nitrogen leached but the amou nt of drainage may be sufficient to dilute the leached nitrogen to acceptable levels.

However, mu ch of Australia is characterised by climates with low rainfall, resulting in more irrigation and less drainage. In these climates, high-yielding agricultural crops with a high nitrogen concentration in the biomass are more effective than trees fo r controlling nitrate leaching.

T h e modelling results provide reassurance that the impacts of eilluent- irrigation on groundwater contaminatio n by nitrate can be kept within acceptable limits if irrigation is managed appropriately and the plant production system is matched to the climate and eilluent characteristics.

icantly degrade the health of water bodies since nutrients contribute to the occurrence of toxic blue-green algal blooms. Consequently, there is increasing pressure to reduce discharge to surface water and to productively reuse treated sewage eilluent by irrigation.

The disadvantage i s that the groundwater may be impacted adversely by salt and nutrients such as nitrate.

Leaching of salt, though important, is not considered in detail in this paper, w hich concentrates on nitrate.

Irrigated tree plantations are an increasingly popular method of eilluent reuse, with already more than 3000 ha in Australia. The popularity of trees for efflu ent reuse can be attrib uted to reported high growth and h igh water use rates, as well as their amenity value.

H owever, research from the Wagga Wagga Eilluent Plantation Project has shown that after canopy closure the net rate of nitrogen accum ulation in the trees decreases significantly . If the trees are not harvested soon after canopy closure and the rate of nitrogen applied in the eilluent remains constant, nitrogen may leach into the groundwater.

On the other hand, harvesting annual crops can remove greater amounts of

nitrogen. This paper models the effects of tree plantations and agricultu ral cropping in the contrasting climates of Perth and Coffs H arbour.

Simulation Modelling Modelling was done u sing the Agricultural Production Systems Simulator (ASPIM) version 1. 4, w hich has been used successfully for many years to simulate many diffe rent cropping systems in a range of environments.

We used APSIM to simulate the effect of eilluent irrigation of crops and trees in the Perth climate (wet temperate climate with winter-dominant rainfall) and trees in the Coffs H arbour climate (wet subtropical climate with summer-dominan t rainfall). Eac h simulation used 22 yea rs of daily climatic data to capture the effect of variabili ty of weather in the sim ulation results.

The simulated management of both the tree and crop systems was designed to minimise nitrate leaching by m aximising the amount of. nitrogen removed in the harvested biomass. The trees were harvested every four years for bio- energy production. Cropping was a no-till system with w heat (win ter) and maize (summer), both grown fo r silage. Simulations were done fo r irrigation drainage rainfall a range of eilluent characteristics.

2000 The same soil type, a Red Kandosol (also known as a red (1) en earth) , was used at both ~ 1500 ¡~ locations. These soils are 'C widespread in Australia and are ~ 1000 usually suitable fo r effluen t 0 ~ irrigation. en :~ 500 Irrigation, applied by sprinKey Words klers, was managed within the N i trate leaching; simulation simulations to maximise water modelling; effluent-irrigation; tree use while minimising drainage. crops trees plantations; groundwater protection Every three days the simulated Introduction Figure 1 Ave rage annual rainfall, irrigation, and moisture status of the soil was Disposal of treated sewage efflue nt drainage for crops and trees grown in the cl imate Perth examined. If the water in the soil was less than 50% of the water into rivers or coastal waters can signif- with an effluent concentrati on of 30 mg N /L 26

WATER MARCH/APRIL 1999

i.s

WASTEWATER stored between the drained upper lim it and the 15 bar suction, sufficient effluent was irrigated to increase the water storage to 95% of the drained upper limit. U nless otherwise stated, the total dissolved salt (TDS) concen tration in the effluent was 800 mg TDS /L. Excess irrigation was applied as required to keep the concentration of salt in th e root zone of the plants below the value that results in a decline in grow th of th e plant being simulated.

Effect of Effluent Irrigation On Trees or Crops Water Balance. Figure 1 sh ows

average annual rainfall, irrigation , and drainage for crops and trees grown in a Perth climate. Trees can use 40% more irrigation than the wheat/ maize system.

There are two main reasons fo r this.

First, because crops are harvested twice a year (leaving bare soil b etween seasons) w hile the trees w ere harvested o nly once every four years, the trees had a greater average leaf cover and so had the potential to use m o re water.

Secondly, evaporative lo sses from interception of rainfall and irrigation were substantially greater in trees. Although substantially m ore irrigation w as applied to the trees, th e drainage from the two system s was similar because irrigation was applied only w hen the soil w ater status indica ted that it was required.

(The m agnitude of the difference b etween tree and w heat/m aize water use w ill vary between climates).

Nitrogen H arvested. W hen effluent nitrogen con centration was low, about the sa m e amo unt of nitrogen was removed in harvested biomass in crop and tree syste m s (see Figure 2) .

H owever , as the concentration of nitrogen in the effluent rose, the am ount of nitrogen h arvested by the crop s increased considerably because at lower effluent concentrations the crop growth had been ni trogen-lim ited. Sim ulation s for other climates, no t shown here, indicated that similar amou nts of nitrogen could be harvested in crops in other regions of Australia w here double

cropping is possible. Although the trees grew a large amount of biom ass, m ost of this was wo od , which has a low nitrogen concen tration. Therefore, the net accumulation of nitrogen in trees w as relatively low. Sufficient nitrogen was applied fo r maximum tree growth even when effluent concen tration was only 10 mg N /L, so tree grow th did n ot increase as effluen t nitrogen concentration increased.

Nitrogen Balance. Figure 3 shows the nitrogen balance fo r the crops and trees in the Perth climate for effluent concentratio ns of 10 and 30 mg N /L. In all cases, gaseous loss of nitrogen by denitrifi cation was small. (A well designed effl u en t irrigatio n system should avoid soils with low hydraulic conductivity, which may prevent the leaching of salt from the root zone, and should sch edule irrigatio n to avoid saturatin g the soil profile. Therefo re, denitrification can be expec ted to be a small or n egligible part of the nitrogen balance in most cases) .

T he amount of effluent able to be applied was not greatly affected by the effluent nitrogen concentration because the leaf area of the crop was sufficient to intercept m ost of the solar radiation even at the lowest nitrogen conce ntration. Therefo re, th e in creased crop grow th resulting from the increase in nitrogen applied did no t lead to sub stantially greater evapo- transpiration. Co n seque ntly , the am ount of ni trogen applied increased approximately in direct proportion to the effluent nitrogen concentration .

Since th e amo unt of ni trogen harvested from trees did not increase with increasi ng efflu ent ni troge n con centration (see Figure 2), m ost of the addi tional nitrogen applied was leach ed. In contrast, becau se the amou nt of nitrogen harvested in the w heat/ maize system in creased wi th increasing effl uen t nitrogen concentration, the amount of nitrogen leached did n ot m crease very much . For example, increasing the efflue n t

-

W heat (winter) Maize (summer)

,E400

-

Trees

z

Effect of Effluent Irrigation On Trees in Different Climates

There are some environmen ts w here the amoun t of nitrogen harvested from tree plantatio ns is sufficiently high for groundwater t o be protec ted. In a clim ate with high rainfall relative to potential evaporation, the amount of drainage is likely to be high and the opportunity for ungation low.

T herefore, the con centration of nitrogen in the drainage water may be so diluted as to be acceptably low .

Water Balance. Figure 4 shows the pattern of rainfall and pan evap oration in Perth and C offs H arbour. Perth has a strongly winter- dominant rainfall and evaporatio n is grea ter than rainfall fo r ni ne months of the year. Rainfall in C offs H arbour is summer-dominant and there is a smaller excess of evaporation over rainfall. There is more rainfall and less irrigation in the C offs H arbour climate than in the Perth climate (see Figure 5) . D rainage in the Coffs Harbour clim ate is 2.5 times tha t fo r the Perth climate. It is im portant to n ote that t he greater drai nage for C offs H arbour is not caused by excess irriga-

Leached 500 ~ - - --

500 ~ - - -- - - - - -- -- - - ~ ~

con centration from 10 to 30 mg N /L increased the am ou nt of n itrogen applied to the crop s by 175 kg N /ha but resulted in little additional leaching. In con trast there was an additional 260 kg N /ha applied to the trees but almost all of that was leached.

The capacity of the w hea t/m aize system to remove nitrogen is limited by the amount of biomass that can be grow n and harvested . R esults of other sim ulations, not shown here, indicated that biomass produ ction reac hed a maximum wh en effluent con centration was 70 mg N /L. At effluent con centration s above 70 mg N /L there was a substantial amount of nitrogen leach mg. For high-stre ngth effl u ents, groundwater can b e protected only if the efflu ent is diluted with water or u sed as an occasional fertiliser rathe r than as an irrigant.

'z"

,E 400

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crops

C) ~

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.,

';; 300

i

[

~ 200

!

"'

200

0

,:;; C

1= ::,

8'100

~ 100

z

<(

_g

0

0 10

20

30 40 50 Effluent nitrogen concent ration (mg N /L)

Figure 2 Average annual amou nt of nitrogen harvested in crops and t rees in a Perth climate for several effluent nitrogen concent rations

10 30 10 30 Effluent nitrogen concentration (mg N /L)

Figure 3 Average annual nitrogen balance for crops and trees grown in Perth climate with effl uent conc-entrations of 10 and 30 mg N / l WATER MARCH/ APRIL 1999

27

WASTEWATER tion, but by the seasonal pattern and amount of rainfall relative to potential evaporation.

Nitrate Concentration of the Drainage Water. Figure 6 shows the

simulated nitrate concentration of the water draining beneath tree plan tations in the Perth and Coffs H arbour climates. The amo unt of deliberate leaching required to prevent salt accumulation in the root zone increases as the TDS concentration in the effiuent increases, and is also affected by the amount of natural leaching determined by the climate. Several combinations of salt and ni trogen concentration in the effiuent were therefore simulated for the two climates to explore this interaction. The simulation results were used to co n struct a contour diagram of nitrate concentration in the drainage (Figure 6). The concentrations plotted are those in the drainage water. Nitrate concentrations detected in the groundwater will generally be lower than those in the drainage du e to dilution from lateral groundwater flow.

Simulated nitrate concentration in dra inage was lower in the Coffs Harbour climate than in t he Perth climate. This was partly because less effiuent was applied, but was mainly due to the greater amoun t of drainage in

the Coffs H arbour climate.

Concentrations of nitrate in the drainage for the Perth climate were qu ite high. For most combinations tested , a considerable degree of dilution would be necessary to reduce the nitrate concentration of the drainage to the d rinking water standard (11.2 mg n itrate- N /L).

N itrate concentration of the drainage in the Perth climate was strongly affected by the concentration of salt in the effluent. The upward-sloping contour lines indicate that the lowest concentrations of nitrate in drainage were found for the more saline effiuents. This effect occurs in climates where there is a need to apply extra effiuent to leach salt accum ulated in the root zone. W hen deliberate leaching is required , although the total amount of nitrogen leached increases, the amount of drainage also increases, so diluting the nitrate in the drainage. The nearhorizontal contour lines for the Coffs Harbour simulations indicate that the natural drainage, due to high rainfall relative to potential evaporation , was almost sufficient to control salt.

The refore, eill uent salt concentration had little effect on the concentration of n itrate in the drainage water.

Conclusions If reuse of effiuent is to be sustainable, groundwater drainage irrigation rainfall quality must be protected within Australian guidelines. t2000 .§.

In most Australian C, climates, when protection of ~ 1500 groundwater is important, ·a; "O agricultural crops have some advantages over tree planta~ 1000 .Q tions in controlling nitrogen cii leaching. Under most condi:W500 tions, high-yielding no-till agricultural crops with a high nitrogen concentration in the biomass will: crops trees produce less biomass Figure 4 Long-term average of rainfall and pan evapora- than trees grown for bioenergy tion for Perth and Coffs Harbour Q)

-

rainfall

-

irrigation

-

drainage

13000

Coffs Harbour

z

E

110mgN /I.

C,

E

Q)

~4

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-~2000

0

90mgN/I.

c

70mgN/I.

~

~

-c

5 1500

~

c

C:

0

8

'illC, 1000 ~ C:

500

oc

0

50mgN /I.

z

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30mgN /I.

1

::,

e w Perth

Coffs harbour

Figure 5 Average ann ual rainfall, irrigation, and drainage for trees grown in the Perth and Coffs Harbou r climates with an effluent concentration of 30 mg N /L

28

result in substantially less leaching, particularly at higher effiuent nitrogen concentrations.

In climates that have high rainfall, resulting in less irrigation and more drainage, the am ount of nitrogen harvested from a well managed tree plantation may be sufficient to protec t groundwater quality. In these climates, there may be a substantial amount of nitrogen leached but the amount of drainage may be sufficien t to dilute the leached nitrogen to acceptable levels.

In su mma ry, bo th a water and a nitrogen balance should be constru cted during the d esign stages of effiuent irrigation schemes. Comparison of the nitrogen irriga ted against nitroge n harvested will indicate the likely magnitude of nitrogen leaching. If nitrate leaching is likely, design or managem ent options to reduce nitrate leaching must be con sidered. Finally, if nitrogen i s unlikely to be the cri tical contaminant, a salt balance should be calculated so that the potential for groundwater contamination by salt can be examined.

The scenarios simulated he re show large differences caused by plant production system and climate.

Quantitatively, the results are only applicable to p erfect management under perfect knowledge. While achievable in the sim ulati ons, such management is unlikely to be achieved in reality, so the sim ulation results should be regarded as quali tative guides. Furthermore, the simulations shown here are for irrigation system s designed to maximise water use while minimising .drainage.

Redu ced irrigation applications will reduce the amount of nitrogen applied and may reduce leaching to an acceptable level.

Perth

-:!

.§. 2500

"iii

• have greater net uptake of nitrogen than trees.

However, they will use less irrigation water than trees so a larger area of land will be required to reuse the same amount of effiuent and they are likely to

WATER MARCH/ APRI L 1999

200

600

1000

1400

1800 200

600

1000

1400

1800

10mgN/I.

Effluent salt concentration (mg TDS /L)

Figure 6 Average nitrogen concentration in the water draining from tree plantations in the Perth and Coffs Harbour climates for several combinations of effluent nitrogen concentration and effluent salt concentration

WASTEWATER T here are reasons other than groundwater protection, such as amenity value and remoteness from the crop market, for selecting a tree plantation to reuse eilluent. Nevertheless, it is important to consider the effect of the choice of plant production system, in combination with the effects of climate and eilluent characteristics, on groundwater quali ty .

These considerations will determine the area required for irrigation and the need for enhanced nutrient removal prior to irrigation with effiuen t.

Acknowledgements The modelling e n vironment and some of the modules used in this study were developed by the Agricultural Production Systems Research Unit, a collaboration of CS IRO Tropical Agriculture and the Queensland Departments of Primary Industries and Natural Resources. We thank John Hargreaves, Neil Huth, and Brian Keating (CSIRO T ropical Agriculture) and Kirsten Verburg (CSIRO Land and Water) for their assistance with asp ects of model development and application.

Data from the Wagga Wagga Eilluent Plantation Project contributed to the development of the model used in this study.

This work was partially funded by the Land and Water Resources Research and Development Corp oration under research grants CWWl 7 and CDF7 and by the Murray Darling B asin Commission and the NSW Department of Land and Water Conservation through their funding of the Wagga Wagga Effiuen t Plantation Project.

References Bond W J (1998) Eilluent Irrigation - An Environmental Challenge for Soil Science. Australian Journal of Soil Research 36, 543-55.

Dillon P J , Pakrou N, Snow V O, Correll R , and Barry K E (1998) Monitoring and Modelling of Leachate Beneath a Piggery Effiuent Irrigation Area. Final R eport on LWRRDC Project CWS5 and Pig RDC Project CRClP. Centre for Groundwater Studies, Centre for Groundwater Studies Report Adelaide, SA. Dillon P J, Snow V O, and Pakrou N (1998) Is Effiuent Irrigation a Sustainable Solution for Water Resources Protection? In 'Proceedings of an International Groundwater Conference, Groundwater: Sustainable Solutions, University of Melbourne, Melbourne, Vic, 8-13 February 1998'. (Eds Weaver T R and Lawrence C R) pp. 39-44.

(International Association of Hydrogeologists: Barton, ACT .)

Myers B J, Bond W J, Benyon R G, Falkiner RA, O'Brien N D, Polglase P J, Smith C J, Snow V 0, and Theiveyanathan S (1998) Principles and Practice ofEffiuent

Irrigated Plantations in Australia. CSIRO Forestry and Forest Products, Canberra, ACT. Myers BJ, Bond W J, Falkiner RA, O'Brien N D, Polglase P J, Smith C J , and Theiveyanathan S (1994) Wagga Effiuent Plantation Project Technical Report.

User Series No. 17. CSIRO Division of Forestry, Canberra, ACT, Australia.

Myers BJ, Theiveyanathan S, O 'Brien ND, and Bond W J (1996) Growth and Water Use of Effluent-Irrigated Eucalyptus Grandis and Pinus Radiata Plantations.

Tree Physiology 16, 211-19.

Polglase P J, Tompkins D, Stewart L G, and Falkiner R A (1995) Mineralization and Leaching of Nitrogen in an EffluentIrrigated Pine Plantation. Journal of Environmental Quality 24, 911 -20.

Smith CJ, Snow V 0, Keating B A, and Huth N I (1998) Managing Nitrogen in Piggery Effiuent Applied to Land. In 'Opportunities and Solutions, National Pig Environmental Conference, Gold Coast, Qld, 14-15 October'. in press (Australian Pig Institute: T oowoomba, Qld.) Snow V 0, Bond W J, Myers BJ, Smith C J, Polglase P J, Theiveyanathan S, Falkiner R A, Benyon R G, Verburg K, and Dillon P J (1998) APSIM-Waste: Prediction of the Fate of Water, Salt, and Nitrogen Following Irrigation W ith Eilluent. In 'National Soils Conference, Environmental Benefi ts of Soil Management, Brisbane, 27-29 April

1998'. (Ed. Mulvey P) pp. 145-53.

(Australian Soil Science Society: Clayton, Vic.) Snow V 0, Bond W J, Myers B J, Theiveyanathan S, Smith C J, and Benyon R G (1998) Modelling the Water Balance of Effiuent-Irrigated Tree Plantations.

Agricultural Water Management in press.

Snow V 0, Smith C J, Polglase P J , and Probert M E (1998) Nitrogen Dynamics in a Eucalypt Plantation Irrigated With Sewage Effluent or Bore Water.

Australian Journal of Soil Research submitted.

Snow V 0, Dillon P J, Smith CJ, and Bond W J (1998) Containing the Risks of Groundwater Contamination From R euse of Effluent. In 'Water Recycling & Sustainable Water Management, 6th NSW R ecycled Water Seminar, Sydney NSW, 3-4 November'. (AWWA: Sydney NSW.)

Authors Valerie Snow, Peter Dillon, Chris Smith, Warren Bond are w ith CS IRO Land and Water and Brian Myers is with CS IRO Forestry and Forest Products. The team is involved in research into several aspects of effiuent reuse and any correspondence may be addressed to Dr V O Snow at CS IRO La n d and Water GPO Box 1666 Canberra ACT 2601. Email may be sent to Val.Snow@cb r.clw.csiro.au.

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BOOKS Dewatering Biosolids FR Spellman, Technomic Pub-lishing Co., 1997, ISBN 1-56676-483-1, 289 pp. $135fromAWWABookshop This book by Dr Frank R Spellman, Environmental H ealth and Safety Manager, H ampton Roads Sanitation District, Virginia, USA covers the nature and composition of biosolids, the objectives of dewatering solids and the characteristics affecting d ewatering.

The principal dewatering processes are covered, and three chapters are devoted to the chemicals used for dewatering, one to safety considerations and one to cost considerations.

The space devoted to centrifuges is as m uch as that for all other processes, thus reflecting the author's p reference.

Dr Spellman uses plain language without buzz words to describe each dewatering process and supplements loading rates, efficiency and chemical addition with process line diagrams, process schematics and photographs of equipment used in specific processes.

These are easy to understand even though the quality of some of them is variable. There are clear definitions of key terms, with simple calculations and some worked examples. Unfortunately

the units are US gallons and feet instead of metric units.

The book would be a useful tool for engineering students, engineers transferring into wastewater treatment and plant operators.

Frank Bishop Egis Consulting

Wastewater Reclamation and Reuse Water Quality Management Library, Volume 10, Takashi Asano (Ed.), Technomic Publishing Company, 851 New Holland Ave, Lancaster, Pennsylvania, 1528 pages, ISBN No. 1-56676-620-6 In 1992 the US National Committee of IA WQ organised eight specialty courses in conjunction with the 1992 IAWQ Biennial Conference in Washington. These courses were compiled into an eight-volume series as the Water Quality Management Library, edited by Eckenfelder, Moline and Patterson. The success of the series as state- of-the-art texts has prompted the editors to expand it.

The indefatigable Dr Takashi Asano of the University of California, Davis, former c hairman of the IA WQ Specialist Group on Wastewater

Reclamation and Reuse, has completed a three-year labour of love to compile the 1528-page volume 10 which covers all aspects of wastewater reclamation and reuse. There are 31 chapters, each of about 50 pages.

This book assembles, analyses and reviews examples of wastewater reclamation, recycling and reuse from all over the world. It is the most comprehensive coverage of the subject yet published and eclipses Dr Asano's previous contribution to Metcalfe and Eddy Edition 3. The list of contributors is not only long, but also distinguished, including leading water recycling proponents and practitioners from around the world over the last two decades.

It is not the complete textbook or a reuse scheme cookbook with readymade recipes. Practitioners will still want to delve into source technical papers and references to complete their understanding of key design issues.

Nevertheless, Asano's Volume 10 will be a useful companion and the first choice as a ready reference for anyone involved in wastewater reclamation recycling and reuse.

John Anderson NSW Public Works

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WASTEWATER

SUSTAINABILITY AND

'SNABWEMs' M Laginestra

'Sustainability' is a great word. Put it ¡with 'environment' and it conjures up images of the great recycling circle of life and waste. A very important concept in today's society and o ne which needs significant nurturing in the development of projects.

The legislative requirement for any project is vundertaking an EIS, the inte nt being to show a min imisation of impact on the environme nt. But sustainability is another thing. Often regarded as unachievable, there are certainly ideals which should be readily embraced by the (sensitive) new age breed (or brood) of water engineers and managers (SNABWEMSs).

Driving proj ec ts on the basis of environmental outcomes was the theme of the regional conferen ce h eld by AWWA's New South Wales Branch at the swank Peppers Anchorage resort, Po rt Stephens from 28-30 August 1998 .

Colin H eath started the proceedings by talking about Sydney Water's sewer overflow abatement program, involving the massive task of completing EISs for 27 sewerage systems. This is largely driven by the perceived environmental be nefits, rather than e ngineering.

Andrew Kasmarik spoke late r in the day on the water quality modelling work undertaken for the project. The task forms the biggest single compone nt of Water Plan 21, the vision of.sustainable wastewater management for Sydney.

David Saunders, of Airvac, spoke on the implementation of vacuum sewerage in the sensitive environment of South Stradbroke Island, Queensland, at the Coran Cove resort. As mu ch vegetation as p ossible was retained, with the resort attempting to be in harmony with the environment, allowing visitors to come in contact with nature.

Dean Makin fro m Henry Walker Treatment described the BNR project for the coastal town of D enmark in Western Australia. The project was a design, build, operate contract partially fu nded by the Commonwealth government to demonstrate innovative Australian technologies. It is a 2000 EP modified IDEA plant, w ith a high degree of flexibility, achieving less than 5 mg/L N and less than 1 mg/L P,

providing opportunities for reuse of high quality efflue nt and stabilised waste activated sludge.

Graeme Watkins of MidCoast Water and Paul Keighery of PPK Environment and Infrastructure described some of the innovative approaches for disposal of wastwater and biosolids for the city of Taree, driven by the EPA's load-based licensing scheme, offering discounts to operators fo r reuse or land application of wastewater. These include subsurface irrigation of playing fields and irrigation of a hardwood plantation (the latter incorporates an educational trial comparing natural forest with plantations).

Duckweed was the feature in an interesting pape r by Robert Bell ofBioTech Waste Management. This often maligned aquatic plant should be seen as a self-contained wastewater treatment system , removing N and P. H e said there was the possibility tha t the harvested biomass co uld be a high protein animal feed. The process is lowtech, inexpensive to install and operate, and ce rtainly suitable for polishing applications, as in maturation ponds, and he had results to prove it.

Geoffrey Coke, Psi-Delta, ou tlined the huge scale efiluent recycling project of high quality efiluent from Adelaide's Bolivar plant to the market gardens of the Virginia triangle. Pe ter Je1iffe philosophised on methods for tackling environmental projects, and Robert Wale reviewed the application of membrane filt ration for water supplies, including t he ability to remove Cryptosporidium and Giardia.

The final day involved site visits to the Fisheries R esearch Institute at Port Stephens and Newcastle's Summerhill Waste Depot.

The papers and site visits demonstrated that the ideals of sustainability and maximised environmental benefits are achievable and can be used to drive projects. So over to all you potential SNABWEMS ...

Author Mitchell Laginestra is a Senior Process Engineer with Egis Consulting, Level 1, 67 Albert Ave, Chatswood NSW 2067 and President of the AWWA NSW Branch.

WATER MARCH/ APRIL 1999

31

ENVIRONMENT

OZON The world's population of frogs is rapidly declining.

In the last 20 years at least 14 species of Queensland frog have become extremely rare or have disappeared from their mountain rainforest stream habitats.

This relatively recent phenomenon of amphibian disappearance is not limited to Queensland, but is occurring on a worldwide scale. In Australia itself, 27 species are breeders, living on the rainforest floor th reatened. Of these, eight may have and returning to the pristine rainforest disappeared altogether. streams to lay their eggs in nests Frogs are extremely sensi tive animals amongst the rocks on the edge of the that can be viewed as bioindicators fo r stream s. the declining health of their ecosystem. According to the Q ueensland Museum, possible causes for the frog 'This is the first frog declines are the effects of acid rain, project that has concenpesticide residues carried in mists and fog, effects of UV radiation on eggs, trated on the quality of unusual weather, effects of feral pigs, natural population fluctuations, and the water as one of the the toxic consequen ces of exo tic factors for viruses and fungi possibly introduced important by imported aquarium fis h . success.'

The latter of these causes, fungal infection, is threatening the survival of the Fleayi's Barred Frog (Mixophyes In cooperation with Lone Pine Koala fleay1), with numerous dead and sick Sanctuary, Sea World and the D epartfrogs being found in a 1996 survey ment ofEnvironment and H eritage, the unde rtaken by the D epartm ent of Australian water industry is doing its Environment and H e ritage and only best to ensure the survival of this rare three confirmed breeding populations Australian frog. Sea World and water remaining. As a result, the species has treatment specialist Ionics Watertec been declared endangered under the have designed a filtration and ozonation Nature Conservation Act 1992 (Qld) system which removes pathogens and and the south-east Queensland Threat- reproduces the pristine water quality of ened Frog R ecovery Team is to investi- the frog's rainforest stream habitat. T his gate captive husbandry techniques as system will be used as an essential part part of a state draft recovery plan. of a captive breeding program to be So what does Mixophyes fleayi have undertaken at Lone Pine Koala to do with water? T hese frogs are creek Sanctuary which is situated in south-

MENT east Q ueensland rainforest w here the frog is known to occur.

This is the first time captive rearing and breeding of the species has been attempted and the collaborative approach to this project is an important step which could save t he Fleary's B arred Frog from extinction.

Ionics Watertec has lo ng been providing the water treatment technology used to provide crystal clear water that is hygienically suitable fo r o ngoing health o f the various dolphin, sea lion and aquarium exhibits at Sea World and so was the natural choice when state-of-the-art wate r treatment technology was required to assist in t his frog husbandry exercise . T he rea ring program will involve experiments in tanks of various sizes to determine if a particular tank size or shapt is more appropriate. Ionics Watertec has previously been involved in the design and treatment optimisation of marine animal life support systems such as large aquariums, dolp hin, whale, penguin and sea lion facilities, quarantine centres and intensive aquaculture systems.

The treatment incorporates a recirculation system, w hich provides a tank volume turnover of ten minutes. The soiled tank water passes through a biological filter prior to sand filtration then ozonation. Ozone is injected to a 20% sidestream of filtered water. An ozone residual is held in the water for five minutes before being removed in a granular activated carbon filter. Ozone residual monitoring equipment is u sed to ensure that ozone is not present in the treated water being returned to the WATER MARCH/ APRIL 1999

33

ENVIRONMENT

Im

,

¡

ENVIRONMENTAL MANAGEMENT AT LOWER MOLONGLO R Hogg, A Wade, A Wijeratne Abstract The Lower Molonglo Water Quality Co n trol Centre (LMWQCC) treats wastewater fro m Canberra and discharges high quality eilluent into the south-east Aust ralian inland river system. Withou t effective and reliable treatment, this wastewater could impact adversely on the ecology of the riverine .system and downstream users.

This paper sum mari ses the comprehe nsive environmental management program at LMWQCC, which i ncludes ISO Ma nagement systems, physicochemical and biological monitoring, ecological studies, and further engineering initi atives, all of w hich have contributed to 100% compliance with its eilluent licence and minimal impact on the receiving water.

Key Words Environment, wastewater treaunent, sewerage, eilluent, river health, biological monitoring, inland waterways, EMS, ecological moni toring Introduction The LMWQCC is an advanced wastewater treatment facili ty operated

by ACTEW Corporation. Constructed betwee n 1974- 78, it is th e main wastewate r treatmen t facility for Canberra's 310,000 residents, and is the la rgest inland t reatm ent plant in Australia. T he plant provides tertiary treatment to produce a high quality effluent discharging into the Molo nglo River n ear the confluence with the upper Murrumbidgee River (see Figure

Platypus swimming below the Lower Molonglo outfall

1). As such, it has significant environmental and public health importance for the region and downstream commu nities.

T his paper outlines the comprehensive approac h to e nvironmen tal management by LMWQCC. T he traditional engineering approach of optimising and improving water treatme n t remains a vital , but not exclusive, element in protecting the environment.

Equally important has been a focus on understanding the impacts of eilluent on river health. By achieving environ-

mental objectives, LMWQCC plays an important role in maintaining a pleasan t, healthy environment for Canberra and downstream comm unities.

T he LMWQCC also takes a responsible approach in stewardship of water.

This requires that effluent be treated and beneficially reused, for example to displace potable water u se fo r landscape irrigation; or alternatively that the eilluen t be fully treated and returned to receiving waters from whence it came, to augment environmental flows. It is n o longe r acceptable to dispose of WATER MARCH/APRIL 1999

35

ENVIRONMENT Following this extensive treatment, wastewater is of sufficient quality to maintain aquatic life, limit the growth of toxic algae, and meet other environmental and community objectives.

Environmental Management Program Regulatory Environment

LMWQCC operates under the recently e nacted Environmental Protection A ct 1997 (ACT ). This legislation places greater responsibility on organisati ons and individuals for protection of the environment, with stringent penal provisions.

The environmental authorisation for LMWQCC sewage treatme nt sets stringent licence limits, especially when compared with controls for other inland wastewater treatment facilities in southeastern Au stralia. Performance results are reported monthly, and a comprehensive annual report is produced.

LMWQCC has achieved 100% compliance for efflue nt discharge over the past two years.

/Sturt Bend

ACTEW Environmental Management Plan

Figure 1 Location map of LMWQCC showing sampling sites for fish and platypus

wastewater in an unsustainable way.

The LMWQCC approach to efiluent use recognises that water is a vital and increasingly sca rce community resource.

Background Typically, 80-100 ML offully treated water from LMWQCC is discharged each day into the Molonglo and M urrumbidgee Rivers.

Without effective and reliable treatment, wastewater from an inland city the size of Canberra would pose a major envi ronmental h azard w hi ch could impact adversely on the riverine system and on downstream users .

Consequently, wastewa te r from Canberra must be returned to receiving waters in as good a condition as feasible.

Each yea r LMWQCC returns in excess of30,000 ML of water to sustain a range of downstream environmental values. The return of well-treated effluent co n tributes significantly to the environmental flow equatio n and to aquatic ecosystem mainte nance. During dry conditions, the effluent from LMWQCC contributes the bulk of flow in the M olonglo River, so it is crucial that the treatment processes be reliable and effective.

36

WATER MARCH/APRIL 1999

LMWQCC is an advan ced sewage treatment plant using physical, chemical and biological trea tme nt processes.

Treatment comprises: • pre-treatment. Efiluent is screened to remove debris; lime and ferrous chlo ride are ad ded to assist in th e primary treatment • primary treatment. Phosphates , organics and heavy metals are precipitated by ferrous chloride and lime, and removed as sludge • biological treatment (nitrification).

Activated sludge in th e bioreactors converts ammonia to nitrates secondary clarification. Solids (activated sludge) from the biological treatment are separated and returned either to the bioreactors or to primary treatment • tertiary filtration through sand and coal • disinfection. Efiluent is chlorinated, followed by dechlorination prior to discharge • di scharge. Clean efflu ent 1s discharged into the Molonglo River.

• incine ration of solids. All solids captured during the treatment process are incinerated; sludge is used as a fuel for the furnace. The resultant ash is sold as an agricultural soil conditioner.

ACTEW has developed a five-year corporate environme ntal management plan (EMP) fo r 1995-2000 attuned to ecologically sustainable development objectives. In support of the EMP, an environmental action program (EAP) is prepared each year w hic h targets achievable environmental actions. For example, ACTEW is committed to the C onunonwealth Government's Green house C hallenge Program and, in resp onse to this, the 1998 EAP includes coordinated action on energy savings at LMWQCC. The corporate EMP and EAP provide a basis for the environmental management programs. They play an importan t role in communicating the ACTEW environmental direction to employees and to the community.

LMWQCC Environmental Management Systems Environmental performance m ust be constantly reviewed to maintain a focus on the most important environmental issues, and to ensure co ntinuous improvement. Quality systems (QS) e nvironmental management and systems (EMS) provide a framework for achieving this.

LMWQCC was the first sewage treatment facility in Australia to gain ce rtifica tion to AS/ NZS ISO 9002 Quality Systems, and was in the first group of facilities in Australia certified to AS/ NZS ISO 14001 Environmental Management Systems. These systems have now been substantially integrated into one management system.

A key feature of the EMS is the e nvironmental management plan (EMP) which is developed following an

ENVIRONMENT Table 1 Effluent monitoring Biochemical oxygen demand Total dissolved solids Suspended solids Total phosphorus Total nitrogen Thermotolerant coliforms Ammonia Acidity (pH) Residua l chlorine

Table 2 Ecological monitoring Macroinvertebrates Fish and platypus Physico-chemical parameters Algae River flows Heavy meta ls Pest icides Organoha logens

e nvironmental audit and risk assessm en t to identi fy significa nt e nvironmental problem s. The EMP is reviewed annually and forms the basi s for an ac tion program and pe rformance measu res whic h are reported on monthly to management.

The k ey E MP obj ec tives for LMWQCC are to: identify and manage potentially significant environmental impacts of the plant's operations • m aintain the ecological health of the receiving waters • promote su stainable management and waste minimisation • promote communi ty consultation.

The Q S and EMS system s have also played an importan t role in enhancing manageme nt and staff performance, by providing a clear framework for personnel to use their judgement and knowledge in decision-making and risktaking. They have also been instrumental in developing a climate of continuous improve ment and assisting in cultural change. The wide acceptance of these manage ment systems, and the contribution to them from all levels of staff, has been a key feature of the success in supporting sys tem' s LMWQCC to achieve business objectives and m eet its regulatory requirem ents.

Environmental Engineering Projects

LMWQCC sewage treatment processes are continually reviewed to improve operational and environm ental p erformance. Recent examples inclu de: • inflow regulation to enable improved process control during peak flow s • con structio n of a storage dam to avoid bypasses of partially treated effluent to the river during h igh flows o r process dow ntime • phosphorus reduction through the use of an industrial pickle liquor waste

product (ferrous chloride) to assist in precipitation • denitrification of returned ni trified sludge. Pilot plant work is in p rogress, and som e reductions in total nitrogen load of the effluent have already been achieved • e nergy redu cti ons. Fo r exa mple, auto thermal incine ration , through utilisa tion of dewatered sludge as a fuel in the furnace • waste minimisation . For exam ple, incinerati on of sludge which is sold as an agricultural soil conditioner. implem entation o f 111- p rocess monitoring and control to obtain real time in formatio n that en ables proactive corrective actio n • improving infrastruc ture, notably works related to fi ne screens ; clarification; disinfecti on; and st ormwa ter diversion. These will all con trib ute to improved en vironmental perfo rmance of the plant.

Process Performance Monitoring

LMWQC C co ndu cts exte nsive p rocess m onitoring , whic h enables optimisa tion of ope rational and environmenta l pe rformance. This includes both on- line m oni toring and laboratory tes ting for mo re- complex analyses.

Effluent Monitoring

M onitoring of the efflu ent di scharge is undertaken to demonstrate regulatory co mpliance with the LMWQCC environmental authorisation (see T able 1). This monitoring is primarily focused on physico- chemical parameters, and is complemented by testing for mi crobiological indicators to documen t re moval of faecal pathogens.

The licence limits set by the environm ental autho ri sation are based on percen tile conce ntrati on values and mass loading limits. This accommodates overall treatment effi ciency, which may vary from day to day (for example, allowing for the exigency of high plant hydraulic loads that may occur under seasonably we t conditio ns), w hile encouraging optimal performa nce over time.

The levels set are stringen t relative to other sewage treatment plants, reflecting the environmental sensitivity of a m ajor inland river system. For example, the following limits apply: • total phosphorus (3 month rolling average)- 0 .3 mg/L (50th p ercentile); 0.4 mg/L (90th percen tile); 25 kg/day (mass load) • total nitrogen (12 m o nth rolling average)-2100 kg/day (mass load).

Ecological Monitoring

O ver recent years, LMWQC C has been refocusing its monitoring program to include ecological monitoring (see T able 2). This complements effluent

mo nitoring, and is undertaken to identify any beneficial or detrimental impacts of effluent discharge on the M olonglo- M urrumbidgee River ecosystem s. Much o f the ecological monitoring program h as been incorporated into the environmental authorisation.

Figure 1 illustrates th e region included in the LMW Q CC ecological m o nito ring progra m , alo ng th e Molonglo and Murrumbidgee Rivers.

This incorporates an ex tensive n etwork of sites upstream and downstream of the outfall which enables a detailed assessm en t of water quality and environme ntal impacts in the receiving waters.

Ecological monitoring is providing a understanding o f stream be tter processes, and the wide range of external stresso rs, including efflue nt disc harges, on rive r h ealth. This program has, to dat e, de mo n strated minimal o r no impact by LMWQCC on the receiving river systems outside the initial mixing zon e.

An importan t facet of this program is biological m onitoring, which i s discussed in m ore de tail in the following section .

Biological Monitoring

Biological m oni toring is a valuable tool fo r m easuri ng the health of freshwate r eco systems. It provides a direct m easure of the effects of anthropogen ic inputs o n stream biota and e nables investigation of the im pacts over a long t1mefram e. This provides va luable compleme ntary infom1ation to physicochemical water quality monitoring .

An e nvironmental and process audi t in 1992 recommended that the biological m onitoring program for LMWQCC be expanded fro m routine algal and aquatic mac rophyte m onito ring t o include m acroinve rtebrates, fi sh and other aquatic vertebrates. The purpose of thi s was ' to measure, and explain in ecological terms, beneficial or detrimental inputs of the LMWQCC discharge on stream biota at two or more trophic levels.'

Macroinvertebrates. Benthic macroinvertebra tes have been w idely monitored as indica tors of aquatic ecosystem health. Macroinvertebrates are macroscopic animals, including insect larvae, crustacea, w orms and molluscs. They inhabit river substrata and sediments, or attach to rock surfaces and aquatic plants. Im portantly, they are very sensitive and responsive to toxins, such as pesticides and heavy m etals, as well as to changes in environmental param eters, su ch as flow, temperature and nutrients.

LMWQCC h as been monitoring benthic macroinvertebrates as part of its river heal th biomonitoring program sm ce 1993. The objectives of this WATER MARCH/ APRIL 1 999

37

ENVIRONMENT program are to assess the differences in benthic community structure between the Molon glo and Murrumbidgee Rivers relative to the LMW Q CC outfall; to investigate p ossible changes in ecosystem conditions over time; an d to determine the nature of impacts of the LMWQCC effluen t on the be n thic community. In the most recent investigation (B ouckaert and Josey, 1998), data analysis included use of the AusRivAS m odel (A ust ralian River Assessm ent System ; Simpson et al. , 1996) from the National River H ealth Program. T his e nables compari son of data from LMWQCC w ith data from othe r regions across Australia.

R esults indicate that the Molonglo River is in poor biological condition compared to the Murrumbidgee River, both up stream an d dow nstream of LMWQCC. Discharge from the plant is only one of a nu m ber of impacts on the river. Others are urbanisa tion , stormw ater flows, the damming of Lake Burley Griffi n , and vari ous o ther upstream inputs. C onsequently, the im pacts from LMWQCC are diffic ult to assess.

Som e positive im pacts of the efflu ent discharge may result from lower turbidity and the contribution to environme ntal flows, whilst negative impacts appear to result from highe r n u tri ents and conductivity. O ther possible impacts include slightly higher temperature at some tim es of the year and generally higher dissolved o>..-ygen.

T he M urrum bidgee 1s slightly impacted down- stream of the confl uence with t he Molonglo , bu t the imp acts appear to be localised and may also relate to the deterioration of habitat substratum fro m surrounding landuse .

Som e changes obse rved in fa una! composition and abu ndance downstream from LMWQCC can be linked to so m e of the physico- chemical variables listed in T able 1. Future studies are being considered with the aim of establishing som e causal relationships between t hese p hysico- chem ical and m acroinve rtebrate variables community structure.

Fish. Fish are an important ecological component of river systems, both as tangible indica to rs of the ecological status of the river and for providi ng recreatio nal ame nity. Monitoring of fish populations provides useful inform ation on river health.

T hree annual fis h surveys have been conducted to date. River sampling sites are located above and below the outfall and above and below the confluence with t he Murrumbidgee River (see Figure 1).

In the m ost rece n t su rvey (Linterma ns, 1998), 920 fish were counted at these sites, w hich included 38

WATER MARCH/ APRIL 1999

six native and five introduced species. • increased nitrogen levels resulting in Results to date have shown that whilst inc reased algal bio mass, providing some native fish appear to avoid the support fo r invertebrate food mixing zone below the outfall, pop ula• beneficial physico-chemical charactertions 5 km dow nstream at the ACT istics, such as slightly elevated temperaborder are not impacted. There have tures; clear low-sediment waters characbeen n o direct effects on fish, and no fi sh teristic of highly oxygenated effluent kills observed due to effluent. Also, fish with low BOD; and reliable augmentaspecies distribution was not sign ificantly tion of flow, typically a minimum of different upstream or downstream of arou nd 80 ML/d LMW Q CC w ith respect to sexual Other Environmental Initiatives maturity or age class, and there was no Stewardship of water resources. increase in parasitic infection rates.

Consistent with its wastewater treatment It should be noted that netting is n ot feasible at median or high flows, and so function, ACTEW has been involved in trials for wastewater recycling. T hese the observed effect relates to low flow include on-site domestic systems and condition s o nly, whe re effl uent W atermining®, both of which provide comp rises t he bulk of flow in the treated wastewater for reuse in irrigation .

M olonglo River.

The W atermining® concept (H ogg et Th ose factors w hich result in apparal. , 1998) involves a small treatment en t migration of some fish species away from the effluent mixing zone may plan t w hich extracts and treats water fro m a sewer and uses the trea ted include marginal elevation of temperawastewater locally, fo r example in irrigature in winter and early spring; slight tion . elevatio n in salinity; small changes in The ACTEW W atermining® facility, water quality such as improved water loca ted at Southwell Park (N orth clarity; and relatively steady state flow Canberra), has th e capacity to produce condition s. It is also possible that sm all SL/s (13ML pe r mo nth) of recycled changes in pH and alkalinity may affect effluent. This is used to irrigate 9 ha of the presence of fish . adj acent playing fields. A five- year study T he advanced level of treatment and

by CSIRO is in progress to ensure that virtual ab sen ce of trade wastes in irrigation has no detrimental impact on Canberra probably preclude any critical the soil or watertable (T an et al. , 1998). toxic effects.

AC TEW recycles some of the treated A number of questions remain fo r effluent from LMWQCC to provide onfuture studies-the impact of fis hing site irrigation , and irrigation for a local pressu res; the size of the effluent mixing golf club. Also, AC TEW is negotiating zone; and the size of the reach of those the use of treated effl uent for agricultural species app arently affected by the purposes. From ACTEW's Fyshwick nuxmg zone.

Sewage T reatme nt Plant, treated effluent Platypus and other aquatic verteis used to wate r playing fi elds at brates. During the fish surveys oth er Duntroon. aqu atic fa una, although not specifically Agri-Ash. Agri-Ash is a by-product, targe ted , were also captured . These resulting from incineration of the limeinclude platypus ( Ornith o-rhyncus anatin us), eastern long- necked tortoise treated sewage sludge at LMWQCC, ( Chelodina longicollis), Murray turtle which is marketed as a soil conditioner (Emydura macquari1) and eastern water fo r agric ultural purposes. 'Th e high ra t (H ydrom ys chrysogaster) calcium content of Agri- Ash enables its use as an alternative to agricultural lime, (Lintermans, 1998). to correct soil acidity. It also has the T he habitat for platypus appears to be be nefi t of a phosph orus content of favoured by the discharge, but observed about 6%. num bers for the o ther non- target species are too low to draw any conclu sions. Surveys have resulted in four to six platypus • 1994 being n etted immediately ::, below the ou tfall, which is Cl. z, more than at any of the other .!2 E sampling locations (see Figure Cl. ::, o ro 2) . R easons for this may be .;O explained by the following DE ::, factors: z • the abundance of decapod crustacea observed immediately Casuarina Camp Pine Ridge Sturt Bend Retallacks below the outfall, possibly Sands Stu rt Hole related to i ncreased calcium availability from lim e treatment Figure 2 Dist r ibution of platypus upstream and of w astewater downst ream of the outfal l near Stu rt Bend (/)

-

4

C)

ENVIRONMENT The use of Agri-Ash in this way provides a mechanism for recycling sewage waste, with b eneficial commercial returns.

Impact of heavy metals from effluent. In high concentrations, heavy

metals can be toxic to aquatic life , particularly to algae.

For Canbe rra's was tewater, the copper which comes principally from domestic plumbing systems was ide ntified as an issue of possible concern.

Whilst some copp er is removed during treatment, generally to within accepted gu idelines (ANZECC/ARMCANZ 1992), concentrations have occasionally exceeded these levels. The concern was whether this copp er affected river biota health.

Studies were conducted for LMWQCC (Apte, 1995a) to determine th e extent of complexation, and hence bioavailability, of copper in the effiue nt.

Tox icity o f the efflu ent was th en assessed u sing th e alga Chlorella pro tothecoides. This alga has been determined by CSIRO to be an indicator organism for assessing toxicity fo r native Australian freshwater systems.

The results have demonstrated that the copper was not bioavailable, and had no toxic effects on targe t organisms. As a resu lt, potentially expe nsive solutions

Resident echldna at Lower Molonglo

for reducing copp er levels, such as banning use of copper water pipes or investing in expensive treatment, we re deemed to be unnecessary .

Sinular studies have shown that lead also had a low bioavailabili ty (Apte, 1995b). Cadmium exhibited a high

level of bioavailability, altho ugh co ncentrations were below guideline levels.

On-site birds and fauna. Bird surveys have been conduc ted fo r over a year at LMWQCC. Although no scienti fic conclusions can be d raw n , th e

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39

ENVIRONMENT surveys provide a reasonable census of bird numbers and species diversity at several locations, both across the site and off- site. Generally, bird populations are comparable in numbers and d iversity to those in adjacent reserves, and higher than in surrounding agricultural land .

It appears that LMWQCC environs provide a protected habitat, including grassland, scrub and woodland ecosystems, w hich appears to be attractive to bird population s. It is proposed to coordinate the efforts of this program w i th similar surveys in su rrounding areas, undertaken by local ornithology groups.

In addition to birds, other fau na are routinely observed on loca tion at LMWQCC. These include kangaroos, echidna, and eastern brown snakes and other reptiles.

Endocrine disrupting chemicals.

Endocrine disrupting chemicals (EDCs) i nclude a range of compounds, such as some p esticides, chlorinated organics, and detergen t constituents, whic h mimic or disrupt the action of natural hormones. Low con centrations of EDCs fo und in the environment have been implicated in a number of reprod uctive system and other abnormalities

in wildlife and h umans. These include 'feminisation,' reduced fe rtility, and decreased sperm counts.

In response to potential community concerns, a survey was conducted of current scientific information (Ryan, 1998) to assess the probability of these substances being present in the LMWQCC effluent. Because of the low level of industry in Canberra, there appeared to be little likelihood ofEDCs being present in the wastewater efllue nt, with the possible exception of alkylphenol polyeth oxylates (APEs), which are surfac tants used in so me dete rgen ts. H owever, testing over a period of t ime did n ot detect the presence of any APEs. A range of other organic compou nds implicated as potential e ndoc rine disruptors are also monitored periodically in LMWQCC eflluent, but have been absent or detected only at very low concentrations. These include PCBs, pestici des, and other chlo rinated compou nds.

As a result, it was concluded that there is little likelihood of significant levels of endocri ne disrup to rs being present in eflluent from LMWQCC. H owever, the situation w ill con tinue to be moni tored as more informa tion beco mes ava ilable.

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WATER MARCH/APRIL 1 999

Conclusion The comprehen sive environ m ental ma nageprogram m ent implemented by LMWQCC, w hich supports its operational management, demo n strates a responsible and effective approach to environmental management.

This has contributed to the successful m anagement of a complex e nvironmental fu ncti on, operating under a stringent authorisation licence and enabled LMWQCC to achieve 100% compliance with its environmental au thori satio n fo r effluent for over two years.

In turn , th is has ensured that Canberra's treated

wastewater discharging into the Molonglo- Murrumbidgee Rivers has a minimal effect on the receiving waters and that the needs of downstream communities and aquatic ecosystems are We would also like to acknowledge t he considerable effort from many LMWQCC staff in implementing and developing the EMP , with particular thanks to Aspi Baria, Brian Harrison and John Monk.

Aspi Baria is thanked for his helpful comments in reviewing this paper.

Carita Brough, Tracey Mythen and Alison Bloomfield are thanked for p reparing the graphics and photographs.

References ANZECC/ARMCANZ (1992) Australian Water Q uality Guidelines for Freshwater and Marine Waters, Agriculture and Resource Management Council of Australia and New Zealand.

Apte S C and Simpson K A, (1995a) Copper Complexation by Dissolved Organic Matter in the Molonglo/Murrumbidgee River System, CSlRO Coal & Energy Technology.

Apte SC and Stauber J L, (19956) Speciation and Toxicity of Dissolved Metals in the Molonglo/M urrwnbidgee River System, CS!RO Coal & Energy Technology.

Bouckaert F and Josey S (1998) B iological Monitoring Report for the Molonglo and M urrumbidgee llivers 1997, R eport No. LMW ENV/ 98-1, ECOW ISE Environmental.

H ogg R W, Tan Y and Wijeratne A, 1998, Southwell Park Waterm.iningÂŽ Facility: Environmental Impact on Irrigated Sports Fields. Proceedings of the 6th NSW Recycled Water Seminar, Sydney, p93.

Lintermans M, (1998). LMWQCC Water Quality Control Centre Biological Monitoring Program, Final 1997 Fish Monjtoring Report, Environment ACT. Simpson J, Norris R, Barm uta L and Blackman P (1996) Australian River Assessment System. National River Health Program. Predictive Model Manual. Cooperative Reseat;{:h Centre for Freshwater Ecology, University of Canberra, ACT (http://AusRivAS . canberra.edu.au/AusR.ivAS/ manual).

Ryan G (1998) A Review ofthe Implications of Estrogenic Compounds for LMWQCC, ECOWISE Environmental.

Tan Y, Clarkson TD, Cook F J and Yang ] Z (1998) ACTEW Reclaimed W ater Reuse Project at Southwell Park, CS!RO Land & Water Consul tancy Report 98-39.

Authors Ron Hogg is the Environmental and Quality Manager an d Asoka Wljeratne is Branch Manager of the T reatment Branch of the ACTEW Water D ivision. H e can be contacted at GPO Box 366, Canberra ACT 2601, E mai l: ron.h ogg@ac tew.com.au. Dr Alan Wade is P rincipal W ater Quality Adviser with the Environmental Policy Group of ACT EW.

~

BUSINESS

·

H Bjornlund, J McKay

Abstract The operations of water markets are becoming more and more crucial in facilitating both environmental and mi cro- economic reform agendas.

Council of Australian Governments (COAG) wa te r reforms and the National Competition Policy rely heavily on market mechanisms to facilitate a more effi cient allocation of water resou rces and alleviate the financial impact of full cost recovery. Under the new capping initiative of the MurrayD arling Basin Commission, where total extraction from the river cannot exceed the 1993- 94 level of developme nt, water m arkets have become the only possible way of getting access to more water. This paper surveys how buyers and sellers in the water markets of the Goulburn-Murray Irrigation District in Victoria and the River Murray in South Australia perceive the operation of these markets.

Introduction Water markets have d eveloped in the south-eastern part of Australia during the last 15 years. It is anticipated that water trade will help alleviate the social impact of raising water prices under a full cost recovery regime. Trade will allow farmers who are not able to pay full cost recovery prices to opt out of irriga tion farming partly or fully, convert to dryland fa rming or leave fa rming altogether (COAG, 1994).

M arkets will also facilitate the reallocation of scarce water resources w hile

annual allocations dwindle under the Murray-Darling Basin Commission's capping initiative. T he concept of water markets and their early workings have over the past years been reported in Water (Pigram et al. , 1994; Stringer, 1995; Bjornlund and M cKay, 1995; Bjornlu nd and M cKay, 1996; McMullan , 1996).

Both M cMullan (1996) and Bjornlund and M cKay (1996) argued that the early water markets in Australia were thin, w ith only few participants active in the market at any given time, and that as a consequence price formatio n was difficult and erratic. Both Bj ornlund and McKay (1998) and Colby et al. (1993) were therefore only capable of explaining 54% to 58% of the price variation w he n analysing p rices paid in the water market using ' hedo ni c regression analysis or fu nctions.' This paper discusses how the market participants have perceived the early operation of su ch markets in Victoria and South Australia and looks for evidence that these markets have

matured .

In the U S, it has bee n w idely accep ted that thin and immature markets have caused wide fl uctuations in market prices and outcomes (Colby et al. , 1993; Brown et al. , 1982; Gardner, 1985). The study by Brown et al. was important in iden tifyinothe . b impact of market efficiency on water prices and outcomes. T heir finding was that in mo re efficient markets, prices are highest and have the least variation; transfer processes are the shortest; and t ransfer co sts are the lowest. The efficiency level of a market was determined by a number of factors such as: • the number of buyers and sellers active in the market • th e prese nce of a group o( professional intermediaries such as brokers who facilitate the flow of inform ation regarding supply, demand and market pnces • the presence of clear and certain approval processes providing certainty to market participants.

Gardner looked at the impact of the

Table 1 How sellers and buyers heard of transferable water entitlements 1994-96 River Murray, SA

GMID, Vic %of Method Newspaper Radio or TV Public meeting Friend or family Other No answer

%of

Sellers

Buyers

Sellers

Buyers

37.0 3.0 20.0 5.0 33.0 2.0

36.2 1.0 4.8 22.9 35.2 1.9

23.1 1.0 2.9 26.9 39.4 0.0

12.0 2.0 8.0 22.0 55.0 0.0

WATER MARCH/A PRI L 1999

41

BUSINESS size of the trading area and the more uncertain transfer 80 fou n d that the larger th e process 111 that area .

71 trading area and the more 70 Approval of trade is linked 61 va ried th e wa ter uses, the 60 to the productio n of an 55 54 higher the water prices and the IDMP but there are no 11:9 0K larger the overall benefits from 50 clear guidelines regarding • Very satisfied trade. w hat is acceptable.

40 D Very dissatiSfied This co ntrasts with the During su rveys of water 26 DNo answer sellers and buyers in the 30 situation in the GMID , Goulburn-Murray Irrigation 20 where specific rules exist to District in Victoria (GMID) 10 determine how large an and along the River Murray in allocation per irrigated 0 South Australia , marke t h ectare an irrigator can 4 2 3 participants were asked a have. This provides a high SA-sellers SA-buyers GM ID-sellers GMID·buyers number of qu es tion s about level of certain ty about the their perception of the transfer likely outcome of an appliFigure 1 Satisfaction with information provided by authorities process including: ca tion, especially since • how they obtained informapotential water buyers can tion about water trade obtain approval of purchase Looking at the difference between • whether they were satisfied with the irrigation area irrigators and private before n egotiating with a seller. help they received from the authorities d iverters, i t was fou nd that private Attitudes to the Transfer • whether they disliked any p art of the diverters most often qu oted o ther Asked whether there was any pa rr of process sources, mainly the relevant govern- the transfer process they disliked, 29% • w hether a third party broker was ment departmen ts-the D epartment of involved wh o helped them produce any Environment and Natural R esources of the sellers and 30% of the buye rs in irrigatio n and d rainage ma nagement (DENR ) and then Enginee ring and the GMID said, 'Yes,' but with a variation in response betwee n the regions plan (ID MP).

Water Supply D epartmen t (E&WS). In (see T able 2). the Lakes Area, public meetings were a Sources of Water Trade It is clear that the more the sellers are 1nore co m mo n source, due to th e being pressured to sell , the more they Knowledge T able 1 shows how the sellers and extensive u se of government-sponsored di slike the process . A significant buyers first heard abou t transferable public meetings in the development of proportion of selle rs w ho disliked the water entitlements (TWE). Within the fi ve-year management plans in the transfe r process we re in the southGM ID, n ewspapers were the most A ngas- Breme r Proclaimed R egion western region , w here most involuntary common informatio n source. Other (Bj ornlund , 1995). transfers took place and the rate of sou rces were public meeti ngs for sellers, Assessment of Information bankruptcy was the highest. It is also the and farnily and frie nds for buyers. T his Provision region w here th e most comm unity was possibly because many sellers had Sellers and buyers were asked how animosity has been expressed against moved into the area recently for non- satisfied they were with the inform ation wate r trade du e to the expected water fa rming reasons, whereas most buyers they received from the water auth ority. export. It appears that the commercial had lived and fa rm ed in the region fo r Their answers are tabulated in Figure 1. farmers disliked the process most. many years.

Table 2 also indicates tha t a larger Sellers and buyers along the River Along the River Murray in South Murray in South Australia we re more propo rti on of th e private diverter Australia, for both sellers and buyers the dissatisfied with the authorities than buyers disliked the process. T his could m ost comm on m ethod of getting inforthose in the GMID. In both areas the be because a smaller proportion of these mation was throu gh newspapers or sellers were generally more dissatisfied buyers u sed brokers in the transfer and friends and family. The buyers got their than the buyers. Aga in, this co uld be were p ersonally involved in the associin formation from other sources more expected since they were often involun- ated paperwork (see Table 5). often than the sellers.

Along the River Murray- in South tarily scaling back their operatio ns or Australia, 33% of the sellers and 40% of leaving fa rming altogether. Anecdotal the buyers said they disliked some part and the negative response to evidence Table 2 Dissatisfaction with transfer the survey by many respondents wo uld of the transfer process. Table 3 shows process in GM ID, 1994-96 the varia tion in respo n ses between su pport this assumption . % of sellers % of buyers private diverte rs and irrigators in irrigaThe h igher level of dissatisfaction Eastern district 25.0 26.4 along th e River Murray in So u th tion areas as well as th e three river South-western district 50.0 33.3 Australia could perhaps be explained by location s.

North-western district Private diverters Tota l for area

21.4 23.1 29.0

20.0 40.0 30.0

Table 4 Element of transfer process disliked , GM ID and River Murray, SA, 1994-96 River Murray, SA

Table 3 Dissatisfaction with t ransfer process along River Murray, SA, 1994-96

Irrigation areas Private diverters Based on location: Lakes a rea Lower Murray Riverland area Total for area

42

%

%

of sellers

of buyers

40.0 17.6

25.0 47.1

7.1 20.0 36.9 32.7

50.1 50.0 37.2 40.0

WATER MARCH/APRIL 1999

GMID, Vic

% of sellers Advertising, intrusion on privacy Time factor Cost factor Red tape, time taken Restrictions on water purchases Forced sale Disagreement with paying for water Various private reasons No answer

61.8 8.8 17.6 0.0 11.8 0.0

% of buyers

32.3 30.0 20.0 7.5 0.0 10.0

sellers

buyers

1 7.2

0.0

17.3 37.9

10.0 66.8

20.7 6.9

16.4 6.8

BUSINESS Within irrigation areas, it was mainly the sellers who disliked part of the process, whereas among the buyers it was mainly the private diverters. This was to be expected since it was mainly the private diverters who were subject to the DENR approval process and production of the IDMP. Sellers in the Riverland area were most dissatisfied.

Table 4 shows the parts of the process wi th which the selle rs and buyers were di ssatisfied . Among the sellers the time factor was by far the biggest problem, followed by red tape.

These were possibly correlated.

Along the River Murray in Sou th Australia, a group of sellers (12%) with annual allocations for vege table production in marginal areas said they disagreed with being forced to sell.

W hen the government irrigation areas were refurbished the alloca tions of these growers were upgraded to formal licences as a kind of compensation.

However, it was not found feasible to co nnect many of th em to the new supply system and th ey were forced to sell their licences. Cost was the most important factor for the buyers beca use they had to produce the IDMP and obtain permission.

Within the GMID, only three obj ections were specified. First was an obj ection to advertising w hat was considered to be a private business matter. Second was an objection to the transfer cost.

The third objection, wh ich concerned the largest group , consisted of the time taken to complete the process and the red tape involved. Among the buyers ' red tape' was the only substa ntial objection. The 'various private reasons' rela ted to individual tran sfers. For example, o ne buyer disagreed w ith paying for water at all.

Transfer Costs During the interviews the buyers and sellers expressed a major dislike of the transfer co st. Tables 5 and 6 report the costs on a per ML basis in the GMID and along the River Murray in South Australia.

Table 5 indicates that a significant number of sellers and buyers in the GMID indicated zero transfer cost. This raises som e concern since both buyers and sellers should have some co st, if only for application fees and advertising.

Otherwise, the transfer costs for buyers were quite consistent, around S 14-15 per ML throughou t the GMID , with the excepti on of the so u th- western region w here the mean cost was only $4 per ML. T his possibly reflects the fact that most of the larger transfers took place in that region with only 42 per cent of all buyers purchasing less than 50 M L. For sellers, the co st in the eastern

region seems to be very high when compared to the other regions. T his could be because almost 75 per cent of all sellers sold less than 50 ML. On the cheaper side, sellers in t he northwestern region paid the least in transfer costs, with an average ofS8.54 per ML. Table 6 shows the range of transfer costs on a p er ML basis along the River Murray in South Australia during the 1994-96 period, w ith overall li ttl e difference between the average transfer price for sellers and buyers. Considering that it was the buyers w ho had to produce the IDMP , this was unexpected . H oweve r, t he market consisted of a large number of smallscale sellers but only a small number of buyers amassing large volumes of water (Howe et al., 1990) B etween irrigation areas and private diverters some diffe rences emerge .

Buyers in the irrigation areas paid less than the private diverters, probably becau se they used brokers much less frequently and many did not have to produce an IDMP (only 47% compared to 72% for private diverters).

T ransfe r costs for sellers in irrigation areas were more than twice those fo r Table 5

Brokers The use of brokers in the transfer process is set out in Table 7. Broke rs were more w idely used along the River M urray in South Australia than in the GM ID. Howeve r, the use of brokers increased in both areas. In the GMID buyers increased the use of brokers by 36% and sellers by 47%. This is a sign

Percentage of buyers and sellers with $/ ML transfer costs, GMID, Vic, 1994-96 0

0-10

10-30

30-50

50+

Mean

17.2 8.8

17.2 50.0

31.0 28.8

17.2 10.0

17.2 2.5

33.19 15.01

5.9 14.3

29.4 85.7

58.8 0.0

5.9 0.0

0.0 0.0

14.54 4.00

9.1 0.0

45.5 68.8

45.5 12.5

0.0 12.5

0.0 6.3

8.54 16.54

33.3 11.8

25.0 29.4

20.8 47.1

12.5 11.8

8.3 0.0

14.65 14.08

18.5 8.8

25.9 50.0

35.8 28.8

11.1 10.0

8.6 2.5

20.43 14.15

$/ML Eastern Sellers Buyers South-western Sellers Buyers North-western Sellers Buye rs Private diverters Sellers Buyers Total area Sellers Buyers

Table 6

buyers, probably because the sellers used brokers twice as frequently as the buyers. For private diverters t he opposite was true -the sellers paid only half of what the buyers did, reflecting the fact that the buyers h ad to produce the IDMP. T he figures for the Lakes Area and the Lower Murray were difficult to analyse because of the low numbers and the high level of missing answers.

H owever, there was a trend for costs to be much lower in these region s, especially among the sellers. T his is probably because the IDMP was less costly here since activities in this area do not affect the salinity of the water abstracted at Morgan to supply Adelaide and do not have the high groundwater salinity levels tha t occur in th e Riverland area.

Percentage of buyers and sellers with $/ ML t ransfer costs, River Murray, SA, 1994-96*

$/ML Irrigation areas Sellers Buyers Private diverters Sellers Buyers Lakes area Sellers Buyers Lower Murray Sellers Buyers Riverland Sellers Buyers Total area Sellers Buyers

0

0-10

10- 30

30-50

50+

Mean

17.1 31.3

4.3 12.5

35.7 31.3

18.6 3.1

8.6 3.1

26.36 10.89

35.3 17.6

11.8 16.2

8.8 33.8

2.9 7.4

5.9 10.3

13.03 25.83

42.9 25.0

28.6 25.0

0.0 25.0

0.0 12.5

0.0 0.0

1.57 13.01

40.0 7.1

0.0 21.4

0.0 42.9

0.0 0.0

0.0 14.3

0.00 29.32

19.0 24.4

3.6 12.8

32.1 32.1

16.7 6.4

9.5 7.7

26.64 20.59

23.3 22.0

6.8 15.0

26.2 33.0

13.6 6.0

7.8 8.0

22.74 21.20

*Missi ng data: Among the buyers 16% and among the sellers 22.1% did not know their transfer cost

WATER MARCH/ APRIL 1999

43

BUSINESS The proportion of Buyers Sellers water buyers 1994-96 who found 66.7 62.6 the IDMP 72.8 62.0 significantly changed their fann management went up from 28% to 40% . This is a reflection of the increased use of private consultants.

A further development is that real estate agents and valuers are expressing interest in operating in the market (Bjornlund, 1994). This has resulted in some brokers calling for a code of practice to be developed (La nd and Water News, 1998).

Table 7 Percentage of buyers and sellers using brokers for water trade Buyers

Sellers

1987-94 GMID, Vic River Murray,SA 1

46.0 57.6

1

45.3 52.6

In Victoria, 1992-94

Table 8 Mean prices paid in the GMID water market($ per ML)

Region

1992-94

1994-96

East West Private diverters

313 (34)* 289 (65) 170 (129)

360 (56) 325 (65) 267 (145)

* Figures in brackets are standard deviations

of a maturing market.

Further analysis of the use of brokers showed that in the GMID during the period from 1994-96 brokers were most widely used by buyers in the north-western region (76%) and the eastern region (70%) against only 56% in the sou th -western region. The most significant difference was among private diverters. Only 30% of these buyers (mainly commercial farmers) u sed a broker, compared to 56% of the sellers.

The increase in the proportion of private diverter sellers using brokers during the 1994- 96 period was probably due to the general increase in private diverter activity in the market caused by the introducti on of trade between private diverters and government irrigators who traditionally have used brokers more widely.

Along the Murray River in So uth Australia the use of brokers increased by only 9% for buyers, whereas sellers increased their use by 38% due to the introduction of trade between irrigation areas and private diverters. Within irrigation areas a m uch smaller proportion (only 38%) of the buyers used brokers compared to p rivate diverters.

On the other hand, sellers in irrigation areas used brokers on a par with private diverters (73% ) . In South Australia a large number of irrigation a~ ~ri~ron scld=rer ro priwre diverters w ho traditionally use brokers more widely. This is probably a reflection of the more rigid approval procedures for private diverters. An analysis of market prices shows that sellers using brokers do benefit from their brokers' increased market knowledge.

Maturing Market As stated above, the use of brokers in the transfer process is a sign of a maturing market. Another sign of this is the increasing use of consultants to produce the IDMPs. During the period from 1987-1 994, 28% of the buye rs produced their own IDMP, whereas during the period from 1994-1996 only 8% of the buyers produced their own plan.

44

WATER MARCH/APRIL 1999

Market Activity and Prices Figure 2 shows the steady expansion of the market in South Australia up to 1996 and a strong upward trend in prices. There seems to be more fluctuation in maximum rather than minimum prices. This reflects the rapidly increasing price level and a permanent shortage of supply. Anecdotal evidence suggests that 1998 market prices are consistently above $1 ,000/ ML. The minimum price fluctuates very li ttle especially w hen comparing with the minimum prices in the GM ID . In South Australia there seems to be more fl uctuation in maximum prices, reflect-

ing rapidly increasing price levels and a permanent shortage of supply.

Reflecting this development, analyses of prices paid in the water market (again using hedonic fu nctions) during the 1994- 96 period increased their explanatory power to 69% compared to the 54% reported by Bjornlund and McKay (1998) during the 1987-94 period.

Figure 3 shows that the water market in the GMID until the end of 1996 remained relatively stable with respect to market activity and maximum prices whereas minimum prices showed wide dispersion. This dispersion is caused by spatial restrictions on trade as well as the limitations on trade between governm ent irrigation areas and private diverter up until 1994.

After 1994 some spatial restrictions were removed and trade was introduced between irrigation areas and private diverte rs. T hese changes allowed increased trade between producers of lower and higher valued commodities as well as trade from private diverters, mai nly using water as drought security, to farmers within irrigation areas using water very intensively.

Table 8 shows mean prices paid and accepted by government irrigators withi n the Western and Eastern parts of the GMID periods as well as private diverters during the 1991 - 94 and

700 - , - - - - - -- - - -- - - - - - - - - - - - --r 45 ~

~

35

500 ....J

:::;;

~

30 .Si If) 25 ~ 20 ::': 0

400

~ 300

15 ci

200

10

100

0

z

5 +u+'~fU+'-'4'-'t'-';'--';"!'-'t'-'!'-'i'--4"-t'-'-r'-'t'-'i'"'i'-'t'-',"!'-'f'-'!'--'l'"'t'-'-t'-'t-"t'-'t'-'f~fU+'-'4'-'l'-'r-'t"!'-'t'-'t-

0

(') (') r-- r-- 00 00 0) 0) 0 0 N N -st" -st" ll) ll) <O <O "i' 00 "i' 00 "i' 00 o;> 0) o;> 0) o;> 0) o;> 0) o;> 0) o;> 0) o;> 0) c!J c!J c!J c!J c!J c!J c!J c!J c!J c!J Quarter of transfer

1---..- Minimum -+-- Maximum c::::::::J No. of transfers I Figure 2

Minimum and maximum prices and number of transfers, River Murray, SA,

1987-96 600 - , - - - -- - - - - - - - - - - - - - - - - -- - -----,- 70

500 60 50 400 ....J 40 :::;; 300 ;,.

30 200 20 100 10 0-f-'--.L.W-L./-=+'--4'-'-l-'-'-+'--'+'-'-+-'-'-+'-~-L./-'-'-+'--'+''--'-i-'-'-+'--'+''--'-i~-+-'--'-+'-'-+0 N

N

,!.

C\J

O>

O>

N

N

O>

O>

d,

"d"

C')

O>

,!.

"'

len ~

:: 0 0 Z

C')

O>

(\J

Quarter of sale c::::=:J fib.

Figure 3

of transfers -Âź- Minimum price -

Maximum price

Minimum and maximum prices and number of t ransfers, GMID, Vic, 1992-96

BUSINESS 1994-96. It indicates that mean prices have evened out across traditional price boundaries and that prices have increased. This supports the findings o f Gardner ( 1985).

Despite the fact that trade has fully opened up, prices received by private diverters remain lowe r (see Table 8).

Analysing water market prices (again using h edonic functions) during the 1994-96 period supports the presence of market inefficiency and indicates its cause. The analysis suggests that private diverters receive lower prices if they are selling to o the r private diverters, whe reas if they are selling to farmers in irrigation areas the prices paid are on a par with market prices paid in irrigation areas. This shows that private diverters are still not aware of the change to trading rules and their implications for water prices.

Conclusion The irrigation com mumt1es have become more familiar with th e market and more confident with its operation and the opportunities it presents fo r both buyers and sellers. The increased use of brokers and agents as w ell as the inc reased marke t activities and the removal o f spatial and other impediments to trade have caused the marke t to matu re.

The article indicates so me dissatisfaction with th e ope ration o f the market, especially along th e River M urray in South Australia. For th e future operation of water markets it is imperative that the transfer processes be streamlined and predictable procedures be developed which offe r wate r buyers more certainty of outcome and limit the

costs associated wi th water trade.

During the research fo r this article the authors search ed regional n ewspapers for informa tion on the operation of wate r market and to their surprise found very little discussion of the topic.

This fi nding, coupled w ith the dissatisfac tion fo und amongst various water market players, indicates a need for the authorities to do a lot m ore work to educate the irrigators.

Acknowledgements T he Land and Wate r R eso urces Re search and Development Corporation in C anberra funded this research as a part of the proj ect, 'Do Trade Policies Achieve W ater Environmen tal and Socioeconomic Goals' References Bj ornlund H (1994) T he Water Industry: C hallenges and O pportuni ties fo r the Real Estate Professio n. Paper presented to the Fourth Australasian R eal Estate Educators Conference, Auckland University, January 1994.

Bjo rnlund H (1995) Water Policies and their Influence on Land U ses and Land Values.

T he Angas-Bremar P roclaimed Region: A Case Study. Property Management, l3 (2), 14-20.

Bjornlund H and McKay J (1995) Can Water Trading Achieve Environmental Goals?

Water, 22 (5), 31-34.

Bjornlund H and M cKay J (1 996) T ran sferable Water Entitlements: Early Lessons from South Australia, Water 23 (5) 39-43.

Bjornlund H and McKay J (1998) Factors Affecting W ater Prices in a Rural W ater Market: A South Australian Experience.

Water R esources Research, 34 (6), 1563- 1570.

Brown L, McDonald B, T ysseling J and

D umars C (1982) Water R eallocation, Market Proficiency, and Conflicting Social Values. In Weatherford G D, Brown L, Ingram H and Mann D Eds. W ater and Agriculture in the West U S: Conservatio n , R eallocation , and Markets. Studies in Water Policy and Management, No. 2, Westview Press, Boulder, Colorado, 191- 256.

Colby B G, C randall C and Bush D (1993) Water Right Transactions: Market Values and Price Dispersion, Water Resources Research, 29 (6), 1565- 1572.

Co uncil of Australian Governments (1994) Com munique . Meeting of COAG in H obart, 25 February 1994.

(1985) In stituti onal Gardner B D Efficient W ater Impediments to Allocation , Policy Studies R eview, 5 (2), 353-363.

H owe C W , Boggs C S and Butler P (1990a) T ransactio n Costs as D etem1inants of Water T ransfers, University of Colorado Law R eview, 61 (2), 393-405.

Land and Water N ews (1998) Water T raders N eed a Code of Practice: Agents, Land and Water News, 2 (9), 7.

McM ullan J (1996) W ater T radi ng in Victo ria: P ossible Controls, W ater, January/February, 34-37.

Pigram J J, Musgrave W F, Hooper B P, Dudley NJ and Bryant M J (1994) Cooperative Federalism and Water Reform , Water 21 (4): 21- 25.

Stringer D (1995) W ater Market and T rading Development in Victo ria, Water, 22 (1), 11-14.

Authors Henning Bjornlund is a PhD stude nt under the supervision o f Associate Professor Jennifer McKay in the Division of Business and En terprise at the Universi ty of South Australia. They can be contacted at email: J ennifer M ckay@unisa. edu.au.

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