Water Journal July - August 1997

Volume 24 No 4 July/August 1997 Journal Au stralian Water & Wastewater Association Th e last two issues of Wa rcr were numbered incorrectly. Th e correct numbering is: Mar/April - Volume 24 No 2 May/June - Volume 24 No 3

Editorial Board F R Bishop, Chairman B N Anderson, G Cawscon, M R C hapman P Draayers, W J Dulfer, G A Holder M Mumisov, P adebaum,J D Parker A J Priestley, ] Rissman

General Editor Margaret Metz AWWA Federal Office (see address below)

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

Branch Correspondents ACT - Ian Bergman Tel (06) 248 3133 Fax (06) 248 3806 New South Wales - Mitchell Laginestra Tel (02) 9412.9974 Fax (02) 9412 9676

CONTENTS

"

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

IN

WATER

Women In Water Make a Splash ....... ... ...... .. .... ....... ... ..... ...... ....... ..... .... ... ... 12 T Flapper, A Dixon MY

POINT

OF

VIEW

Beware of Snake Oil Salesmen ... ..... ... ... ... ..... .... .... ... ... ..... ... .... ....... ...... ... .. ... 3 RLoo

Northern Territory - Bill Bean Tel (08) 8924 7201 Fax (08) 894 1 0703

WATER

Queensland - Tom Belgrove Tel (07) 3810 7967 Fax (07) 3810 7964

South Australia - Peter Marrin Tel (08) 8303 8723 Fax (08) 8303 8750 Tasmania - Ed Kleywegt Tel (036) 238 2841 Fax (036) 234 7109 Victoria - Mike Muntisov T el (03) 9600 1100 Fax (03) 9600 1300 Western Australia - Jane Oliver Tel (09) 420 2462 Fax (09) 420 3178

Advertising & Administration AWWA Federal Office Advertising: Lynne Mathias Graphic Design: Elizabeth Wan PO Box 388 Artarmon SW 2064 Level 2, 44 Hampden Road, Artannon T el (02) 9413 1288 Fax (02) 94131047 Email: awwa@inta.net.au

Water (ISSN 0310 - 0367) is published six times per year: Januaty , March, May, Ju ly, Septem ber, November by

Australian Water & Wastewater Inc ARBN 054 253 066

Federal President Mark Pascoe

Executive Director Chris Davis Australian W ater & Wastewa ter Association assum es no responsibility for opi nions or statements of fac ts exp ressed by co ntributors or advertisers and editorials do not necessari ly represent the official pol.icy of th e organisation .

Di splay and classifi ed adve rti se ments are included as an information service co readers and are reviewed by the Editor before publ ication to ensure thei r releva nce to the wate r environ ment and to the obj ectives of the Association . All material in Water is copyright and should not be reproduced wholly or in part without the written permi ssion of the Ed itor.

Subscriptions Water is sent co all members of AWWA as one of the privileges of membership. Non-members ca n obtain Water on subscription at an annua l subscription rate of $39 (surface mail).

Aquifer Storage and Recovery of Stqrmwater Runoff .... .. ... ... ......... ... ..... .. . 7 P Dill on, P Pavelic, X Sib enaler, N Gerges, R C lark WASTEWATER A Strategic Review of the Water Treatment Industry ....... ........ .. .......... ... . 14 D Bainbridge Power Generation from a Large Covered Lagoon ... ... .. ..... ........ .. ......... .. ... 19 G R N icholas, P R Harris Wastewater Treatment by Lime and Sea Salt Brine ........ ......... ................ 23 A Shanableh Gorillas and Recycled Water .... .. .. .. .. ...... ........ .. .. ..... .. .... ...... .. .. .. .. ... .. ........... 27 M Lagines tra ENVIRONMENT Victoria's Groundwater Protection Policy ... .. ..... .. .. .. .. ......... .. .. .... .... ...... .... 29 D Strudwick Current Cleanup Technologies and Practices In the United States ...... .. 36 M E Peterson BUSINESS Corporate Governance and Stakeholder Expectations ...... .. .... ... .. ........ .. . 39 N L Scheinkestel DEPARTMENTS International Affiliates .. .. .. ........ ....... .. .... ... .... .. .. ...... .................. .... .... ..... ..... .. 5 From the Bottom of the Well .. ......................... .. .. ....... .... .... .. .. ..... ....... .. ........ . 2 Meetings .......... ... ..... .. ...... ... ... ................ .. ............ .. ..... .... .. ........ ... .... ... ..... .... .. 48 New Product .... .. .... .. .... ..... ........ ....... .. ..... .. .. .. ...... .... ..................... .. ., ...... .. ... .. . 48 OUR COVER : Taronga Z oo 's Gorilla Forest has a m oat filled with recycled water from the Zoo's wastewater treatment plant. Th e water is changed every two months and the quality of the recycled water produced-with zero coliforms and virus indicators-is of a much higher standard than that required by current NSW R ecycled Water Guidelines. See our sto1y on page 27. Photo of Western Lowland Gorilla 'Ki.babu ' by Rick Stevens courtesy ofTaronga Zoo.

WATER

AQUIFER STORAGE AND RECOVERY

OF STORMWATER RUNOFF P Dillon, P Pavelic, X Sibenaler, N Gerges, R Clark

Abstract Reuse of reclaimed water via storage in aquifers ca n lead to more environmentally sensitive urban design, with . reduced req uirements for imported water, reduced exports of sewage and stormwater to po tentially sensitive ecosystems and lower water supply costs than would otherwise be possible. Such water does not necessarily have to be of potable qu~li ty.

T his paper concentrates on the development of new water resources by harvesting stormwater, storing it in aquifers, and recovering it for irrigation.

C logging of the rec harge system, protection of existing beneficial u ses of gro undwater and the quality of the recovered water all have to be considered. N ew guidelines for the quality of water to be injected into aquifers in Australia that take account of these obj ertives have recently been developed .

A series of investigations is continuing in South Australia. The evidence to date indicates that economic and technical feasibility and environmental su stainability are predictable and achievable.

Key Words Water resources , aquifers, recharge, irrigati on water, stormwater, reclaimed water

This paper was awarded the Michael Flynn Award for the best paper in the Public H ealth and Amenity stream of AWWA's 17th Federal Convention Proceedings . It has been updated for publication in this issue of W ater.

Introduction The cost of expanding water supplies is an important factor in favour of aquife r storage and recovery (ASR) of stormwater and treated efiluent in arid, semi-arid and monsoonal areas w here there is a surplus of water for part of the year and long dry periods w hen water demand is high . Because this forces up the value of the water resource, the cost of value-adding by storage of otherwise wasted water can be considerable, and artificial recharge may be the lowest cost option for increm ental expansion of water supplies.

Another maj or cost driver for water reuse via aquifers is the need to protect the marine and fres hwater ecosystem s into which stormwater and treated wastewater are disposed.

With the improved quality of treated wastewater becoming available, largescale commercial ventures involving reuse on food crops are being developed. However, some form of wet season storage for treated wastewa ter is

Figure 1 Aquifer storage and recovery sites, Adelaide

needed. T he water treatment requirem ents for was tewater ungation , combined with aq uifer storage and recovery, are different from those for disposal to a marine environment, and m so me cases may b e substantially cheaper.

Recharge Methods Artificial recharge may be deliberate or incidental. Examples of incidental artificial recharge are irrigation, leaky water supply and sewer pipes, unconnected sanitation, and geothermal heating/cooling systems. While these may have enormous effects on the level or quality of groundwater, they are not dealt with here, as this paper focuses on deliberate efforts t9 increase aq uifer storage.

While there has been much written about recharging of aquifers with water of potable quali ty, or tertiary-treated wastewater which is close to potable, the use oflower quality source waters to repleni sh brackish aq uifers to create n ew irrigation resources is relatively new. This paper concentrates on the development of new water resources by harves ting stormwater, storing it in aquifers, and recovering it for urban landscape irrigation or irrigation of crops.

T he choice of method will depend on local conditions and obj ectives. For

Figure 2 The Andrews Farm site WATER JULY/AUGUST 1997

7

WATER example, pond recharge is likely to be the cheapest option if there is a transmissive unconfined aquifer, pernieable soils and the price of land is low. In a c,ity with high land pri ces, or impermeable soils and a co nfined aquifer , recharge via well s is likely to be preferred.

Unconfined aquifers and permeable soils have advantages in that rates of recharge are high , the costs of establishing facilities are generally lower, and additional treatment is provided in the passage of wa ter through the unsatura ted zo ne above the watertable. Their draw backs are that overlying urban areas can adversely affect groundwa ter quality; if the aquifer overfills waterlogging can occur; and, unlike confined aquifers, the transmission of pressure is ¡ only at the slow rate of movem ent of wa ter through the aquifer. The quality of native groundwater is also an important determinant of the feasibili ty of aquifer recharge and reuse.

In urban areas with permeable soils, drainage system s are often designed so that runoff from roofs and impervio us areas can enter small-scale soakage pits with the overflow reaching drains w hich incorpo rate larger soakaway ponds . Therefore a substantial proportion of runoff artifi cially rec harges aquifers. In so me Australian cities such as Perth this helps to maintain water levels in we tlands and repleni sh es groundwater reserves w hich are the source of irriga tion wa ter over the summer dry season .

Where urban areas have clay soils, such as most of metropolitan Adelaide, until recently little urban stormwater runoff was retained and drainage sc hem es m erely accelera ted its di scharge into the sea. Limes tone aquifers are present benea th the city, but cannot be economically connected to stormwater by detention ponds or spreading basins because of th e low seepage rates through the surfi cial clay.

However, w hen holes are drilled a hundred or so metres to these underlying limestone aquifers, the connection is made, and winter runoff can be stored until summer using the aquifer as an underground reservoir. Urban runoff is collec ted and trea ted in detention basins and we tlands w hi ch are constructed to reduce flood risk and to improve the quality of stormwater and receiving waters. The water is then fed by gravity or pumped into the inj ection Table 1 Sou rces of Water Used

by Adelaide Metropo litan Coun ci ls 1994-95

Source of water Mains water Groundwater Recycled effluent Recycled stormwater

8

WATER JULY/ AUGUST 1997

%

87 .6 11.4 0.7 0.3

well via basic treatment systems such as screens or filters. The recovered wa ter generally requires no trea tment w hen used for irrigation.

Role of Aquifers in Urban Water Management Aquifers provide underground reservoirs for infiltrated and inj ec ted wa ter.

T h ey also provide treatment and a multidirec tional distribution netvJOrk. In cities such as Perth, w here about one third of urban wa ter use is derived fr om wells, and groundwa ter-fed wetlands are regarded as having high conse rva tion and am enity value, aquifers are considered a valuable asset.

From a water supply perspective, the volume of constru cted surface water storages would need to be expanded by more than 50% in order to have the same d gree of security of supply if Perth's aq uifers were not available for reticulated and private well supplies.

In other Australi an capital cities aquifers may be considered a latent asset. When developed these have the capa ci ty to radically improve the effi cien cy of urban wa ter u se. In Adelaide , for example, th e sources of water used by metropolitan councils (predominantly for irrigation) are only just beginning to reflect the opportunities for reuse, and with aquifer storage and r covery it is possible that more than half the municipal demand co uld be m et by water recycling (see Table 1).

This would free up mains water for more highly valued uses, and assist in relaxing Adelaide's depe ndence on the River Murray as its major water supply .

R eticulated water use in Australia's seven largest cities has been stable over the las t 12 years, with only two cities having growth in excess of 1% (the largest being Perth at 1.5% pa). Three cities have had a decline in consumption in spite of populatio n increases and all cities have had a decline in consumption p er capita of betwee n 0 .4% (Sydney) and 2.7% (Canberra) .

Under these circumstances, none of these cities should be contemplating large capital investments in new dam sites to meet urban water demand.

Instead there is an ideal opportunity to be innova tive in mee ting growth in local water demand , for example in new subdivision s, by tailoring stormwater and wastewater reuse schemes w here there are suitable aquifers. Sewer mining is an example of such innovation, and a feasibility study was undertaken recently to assess effluent treatm ent and reuse for irrigation in M osman Park, Perth (Sinclair Knight Merz, 1996) . In general, aquifer storage is more favo urable where the source wa ter supply is irregular or seasonal, or poorly matched with seasonal dema nd ,

if wa ter supply is the dominant cost driver for water reuse.

The other major cos t driver for water reuse via aquifers is the need to protect the marine and freshwater ecosystems into w hi ch stormwa ter and treated wastewa ter is disposed. Through public opinion, endorsed by comm onwealth and sta te gove rnments in Au stralia , environmental protection agencies have gained powers to li cense the wastewater discharge by water corporations. T he level of sewage treatment required in future w ill in many cases be much grea ter than it is today, and large capital investments in treatment plants wiU be required. For exa mple, it has been estimated that the costs in Adelaide for upgrading its four STPs will be $150 m.

Opportunistic reuse of this water for irrigation of golf courses and parks has occurred for many years, but with the improved quality of treated was tewater beco ming available, large-scale commercial ventures for wastewa ter reuse o n food crops are plann ed.

H owever, over we t w inter months w hen irrigation is not required, some form of storage for wastewater is needed (Gerges, 1996) . The water treatment requirements for wastewa ter irrigation and aquifer storage and reuse are different to those for disposal to a marine enviromnent, and may be substantially cheaper (Kinhill , 1996).

Water Quality Issues in Artificial Recharge and Reuse: Guidelines There are three related obj ectives to be addressed in determining the degree of pre- trea tment for water to be inj ected into aquifers for re use. Firstly, irreversible clogging of the inj ection well needs to be avoided. Secondly, existing beneficial uses of groundwater nee d to be protected . Finally, the quality of the recove red water needs to meet the requirements for its intended uses. New draft gui delines fo r the quality of water to be inj ected into aquifers were produ ced and disseminated widely for comment (Dillon and Pavelic, 1995). The resulting revision has been produced to serve as a national template, taking account of these objectives (Dillon and Pavelic, 1996).

These guidelines differ from those in use in other countries for two main reasons. They consider beneficial uses in addition to human consumption, and they take into account sustainable trea tment occurring within the aquifer in determining w hether the 9bj ectives will be met. The guidelines conform to the principles of the National Water Quality Management Strategy, and refer to the relevant water quality guidelines to determine fitness for each beneficial use (or environmental value) .

WATER This means that m uch lower levels of treatment than are currently employed elsewhere in the world can be adopted if ambient groundwater quality does not meet potabili ty criteria, and w here the intended use of recovered water is for irrigation. In fac t, it is possibl e to re habilitate aquifers w hich are curren tly too brackish for irrigation by injecting fres h stormwater so that the recovered water meets irrigation requirements.

T his is a common situation in semi-arid regions with relatively low recharge rates to aquifer systems.

SA Experience of Stormwater Injection and Reuse W hile artificial recharge has been conducted extensively throughout the world, including Australia, injection of water into aq uifers is less common, with possibly less than 100 operational sites (Dillon et al., 1994). In South Australia research and development has concentrated so far on injection of stormwater into limestone and fractured rock aquifers.

The objectives of this work are: • to develop the technology and identify w here it can be used successfully • to reduce reliance of urban users on imported water • to improve the quality and economic value of marginal groundwater resources • to provide a new tool for efficient, coaj unctive use of resources.

T he benefi ts are seen to be (Gerges et al., 1996): • res toration of pressure in depleted aquifers (e.g. N orthern Adelaide Plains) • localised reductio n in salini ty in brackis h aquifers for irrigation reuse (e.g. Andrews Farm) and town water

supply (e.g. Clayton) • reduced water supply costs to country towns (e .g. Clayton) and along existing pipelines • additional water supplies are available in association with flood mitigation (e.g. N orthfield) • more highly va lu ed uses can be assigned to treated reticulated water (e.g. The Paddocks, Scotch College).

Table 2 summarises the situations in which aquifer inj ection operations have been established in Australia. With the exception of Angas Bremer these are all in urban areas or country towns, and all except for M t Gambier are situated in the Adelaide region (Figure 1). A series of investigations is continui ng with varying degrees of intensity in the monitori ng effort applied at the different sites depending on the current level of understanding of groundwater treatment, solute transport and mixing processes as well as the risk of clogging and groundwater contamination. The following example from the Andrews Farm site serves to demonstrate some of the issues and outcomes of these investigations.

Andrews Farm Pilot Project In the early 1990s aquifer storage and recovery of stormwater with minimal treatment for non-potable purposes had not been attempted in Australia. We were unable to find results of investigations identifying the impact of ASR of non-potable water on groundwater quality and well clogging which provided the level of detail required to understand subsurface processes and to evaluate the feasi bili ty and po ten tial impacts at other sites. A pilot study was therefore established in April 1993 to evaluate the technical viability and

environmental sustainability of injecting urban stormwater into a brackish confined aquifer for storage of irrigation quality water. Following is a brief summary of the results from the first four seasons of monitoring variables related to water quality, movement and m1x111g, and well clogging. T his includes a description of the techniques used, the problems encountered and their resolution. Greater detail can be found in a report by Dillon and Pavelic (1996) .

Site Characterisation and Expe rimental Program. The study site is

located in a new suburban development known as Andrews Farm on the northern fringe of the Adelaide metropolitan area (Figure 2). T he water source for injection is stormwater runoff derived from a peri-urban surface water catchment (residential and sheep grazing), which covers an area of 55 km2 .

The uppermost 19 m of a confined Tertiary aquifer situated 105 metres below ground surface was targeted for inj ection. T hree observation wells were drilled at distances of 25, 65 and 325 metres downgradient of the injection well. T he aquifer is comprised of variably cemented fine carbonate and sand material, with transmissivity of 180 m 2 day- 1 and storage coefficient of 5x10-4, measured by aquifer pumping tests (Gerges et al., 1996).

Ephemeral stormwater runoff is held in a detention basin, and pumped via a screen and the injection well into the aquifer. In the period from August 1993 to M arch 1997 there were five major inj ection events (see Figure 2). T he first was mains water and the remainder stormwater. A total of approximately

a

Table 2 Summary of Aqu ifer Injection Operations in South Austra lia Site

Aquifer Type (Reference)

Bore Recharge Ratel/sec

Source of Water

Infrastructure

Stormwater

300 drainage wells

River flow

- 30 drainage wells

5 - 40 (gravity)

(Year of commencement)

Annual Recharge Volume ML

Mt Gambier (late 1800s)

Tertiary Limestone (Telfer, 1995)

Angas Bremer (mid 1970s)

Tertiary Limestone (Gerges et al., 1996)

2800

Andrews Farm (1993)

Tertiary Limestone Confined (Pavelic&Dillon, 1996; Dillon et al., 1995; Gerges et al., 1995, 1996)

Stormwater

wetland 1 injection well 3 observation wells

15- 20 (gravity or pressure)

60

Greenfields (1995)

Tertiary Limestone Confined (Gerges et al., 1996)

Stormwater

10 - 15 (gravity)

100

The Paddocks (1995)

Tertiary Limestone Confined (Gerges et al., 1996)

Stormwater

wetland 1 drainage well 1 observation well wetlands 1 injection well

8

80

Clayton (1995)

Tertiary Limestone Confined (Gerges et al., 1996)

River flow

1 injection well 7 observation wells

40

Scotch College (Torrens Park) (1989)

Fractured Rock (Armstrong; pers. comm .)

River flow

1 injection well 1 production well

15 (gravity)

40

Northfield (1993)

Fractured Rock (Stevens et al., 1995)

Stormwater

wetland 1 drainage well 1 observation well

10- 15 (gravity)

40

1000

I

70

WATER JULY/AUGUST 1997

9

WATER 250 ML of water was inj ec ted. The rate of recharge va ried from 15 to 20 Lsec 1 .

Water Quality and Guidelines for Beneficial Use. Stormwater and

ground water were analyse d for a numb er of physical, ch emical and microbiological parameters. The mean conce ntrations of a subset of these are shown in Table 3 with Au stralian guideline values for drinking and irrigation wa ter.

Characteristically, th e stormwater has higher concentratio ns of dissolved oxygen, nitrate, organic carbo n, microorganisms, and higher pH and turbidity, but has lower concentratio ns of total dissolved solids and iron than ground wa ter. Mixing increases with residence time in the aquifer, and the chemistry of the mixed wa ter approaches that of the ambient groundwa ter.

Following inj ec tio n , only faecal coliforms (on occasions) may exceed the guid eline for irri ga tion water.

(Tabl e 3 shows only mea n valu es).

Faecal coliforms exceed the guidelines for drinking wa ter (Na tional Water Quality Management Strategy, 1992) in the post-inj ection waters, although they die off to levels w hi ch are acceptable wi th respect to these guidelines within a period of fo ur weeks (Pavelic et al. , 1996). Studies are under way to assess the survival of pathogens which are more long-lived than coliform ba cteria (Pavelic ct al. , 1997). Until this work is concluded , recovered waters should not be used for drinking without disinfection .

All other parameters have little or no detrimental impact on groundwater quality, and often have a benefi cial impact (e.g. TDS) . N ote that pnor to inj ection, groundwater did not meet the drinking water guidelines w ith respect to total dissolved solids and iron.

Of the tra ce organic co mpounds monitored, only atrazine (a common

Table 3 Guidelines and analyses for stormwater and groundwater Parameter (mgL·1 )

Guidelines: Irrigation

Drinking

pH

6.5-8.5 >6.5

DO Turbidity (NTU) TDS Ammonia-N Nitrate+nitrite-N Iron

4.5 -9

1000 0.01 10+1 0.3

1.0

Faeca l coliforms U100ml)

0

1000

• mean concentration in 1994

b

65 m obs. We ll

herbicide) and pentachloro phenol (a commonly used wood preservative), were detected in stormwater and observa tion wells at levels substantially below the drinking water guidelines.

Movement and Mixing of Injected Waters. T he movement and rnixing of

~

Q)

WATER JULY/ AUGUST 1997

Groundwaterb

8.2 9.7 50 190 0.044 0.23 0.16 4.3 293

DOC

the inj ec ted waters in th e ambient groundwater were traced by relying on their contrasting electri cal conductivities (EC). Figure 3 shows the EC of the inj ec tan t and gro undwater at each observati on well with time. The 25 m observation well and the inj ec tion well have almost identi cal piezometric pressures and water quality parameters due to hydraulic connection created during inj ection well development.

This provides an effective radius for the inj ection well of approximately 25 m (Gerges et al. , 1996). EC data shows that as of D ecember 1996, the bulk of the inj ected water had yet to reach the 65 m well (as indicated by the high EC values). Slight and temporary declines in EC at 65 m during injection events indicate the possibility of preferential flow along more permeable zones in the aquifer. A decrease in chloride concentration and the detection of coliforms also support this hypothesis. Analytical modelling has shown that the volume of water inj ected could not have reached this distance during 1993 by piston flow alone.

Increases 111 300 ~ EC at the inj ec4 storm water injections 2001:::; 1 mains tion and 25 m water '::,J ~ ::i: between wells 100 ~ injection J ij ":,,i events inj ection O Z 5000 mixing suggest with ambient 4000 groundwaters remaining in the 3000 pore spaces • injectant E u around the in• injection wel l U) ::, • 25 m wel l well. j ection 2000 • 65 m well This form of • 325 m well mixing becomes 1000 less apparent in successive seasons as the less May-93 Nov-93 Jun-94 Jan-95 Jul-95 Feb-96 Aug-96 Mar-97 mobile ambient groundwater is displa ce d by Figure 3 Electrica l conductivity in stormwater and groundwater

10

Stormwater•

c

7.7 0.7 13 2340 0.029 0.09 0.45 1.2 0

specific to vegetation species

inj ected stormwater.

Clogging. Various forms of clogging have been encountered as a result of stormwater inj ection. T he earliest, and most easily recognisable, was by zooplankto n , w hich was the only form of clogging to halt inj ectiQ11.

This was alleviated by shielding the pump intake with a filter fabric (Gerges et al. , 1995 ). Some suspended sediments accumulate around the large contac t area at the inj ection well and aquifer interface. Because the parti <:_le size range of the inj ectant (median 4 µm ) is mu ch smaller than that in the aquifer (m edian - 120 µm ), most of the inj ec ted parti culates penetrate the aquifer and possibly·settle at larger radii from the inj ection well, but this has yet to be confirmed . H ekmeij er (1997) showed that physical clogging causes some head buildup around the inj ection well, but no t of significant concern to th e operation.

Clogging can be overcome by effective redevelopment of the inj ection by air-lifting. After the early zooplankton problems , w hich required the well to be more frequently redeveloped, experience was gained to enable thi s to be extended to once or twic e a year .

Monitoring of the suspended sediment load , along with the particle size distribution of the se diments extrac ted during airlifting, shows that a very small proportion of these C 1%) are derived from the stormwater (Figure 4 shows the di stribution after 11 minutes of airlifting). Most extracted sediments are derived from the sands of the aquifer matrix, which are mobilised as calcite di ssolves (Rattray et al. , 1996). Organic matter is filtered around the inj ection well resulting in growth of bac teria , which may contribute to clogging in the short term.

Well

I

PIiot Study Outcomes and Future Work. The Andrews Farm pilot study

was the first well-instrumented and monitored ASR site to use passively treated stormwater in Australia. R esults from the study show that the facility is capable of providing water suitable for

WATER

100 80 -

..., C

Q)

60

u

<ii

0..

•

aquifer sediments stormwater sediment s 12! extracted sed iments (t = 11 mins.)

o

settings . The evidence to date indicates that economic and technical feasibili ty and environmental sustainability are achievable and are becoming more predictable.

40

Acknowledgements 20 -

The study reported in this paper is a collabora1-3 100-300 > 1000 1 0 -30 tive research exercise of 3-10 30-1 00 300-1000 the Centre for Particle diameter (um) Groundwater Studies, CSIRO Land and Water, Figure 4 Particle size distribution of aquifer, storm wat er and Mines and E nergy SA, extracted groundwater sed iments Au strali an Centre for W ater Qu ali ty R esearch irrigation. It is possible that with the and the Hickinbo tham Group. The treatment provided in the aq uifer, a research was supported by the Urban drinking water supply could ultimately Water R esearch Association of be developed. As with many pilo t Australia and the CS IRO Urban Water experiments, technical problems have Systems R esearch Program. Editorial been enco untered but overcome . The assistanc e was provided by Trevor research at thi s site is co ntinuing and Pillar, CGS. includes : • m easuring the survival of pathogens References Dillon, P.J., Hickinbotham, M.R. and in groundwater Pavelic, P. (1994) R eview of interna• inferring the geochemi cal interactional experien ce in inj ecting water into tion s between stormwa ter, ambient aquifers for storage and reuse . Preprints groundwater and the aquifer matrix Water D own Under '94 (!AH XXV • quantifying and predicting the rates Congress and IEAust Int. H ydro!. and of physical clogging Water R esources Symp., Adelaide, Nov 1994) IE Au st NCP 94/ 14, Vol 2A, • modelling the mixing of wa ters in the p13-19. aquifer and the fate of contaminants.

Dillon, P.J and Pavelic, P (1995) Draft guideThese will allow refinements to the lines for the quali ty of stormwater and guidelines discussed above (Dillon and treated was tewa ter for inj ec tion into Pavelic, 1996) . aquifers for storage and reuse. Centre fo r

Conclusions In arid and semi-arid reg10ns planners should allow for innovative wa ter management w h en designing new developments. This may m ea n allocating open space near creeks, urban drains and sewers to provide for passive trea tment systems or engineered trea tment plants before inj ection . An understanding of the hydrogeology of the area will be essential to determine the potential for aquifer storage and recovery.

If information such as the type, thickness and depth of aquifers, current groundwater quality and storage and transmissivity is taken into account w hen planning, this can have a marked impact on the wa ter imports and stormw ater and efflu ent exports required for a new development. As we try to make urban areas more environm entally fri endly, an awareness of underlying groundwater system s will therefore be of valu e to planners. It can also lead to reduced water infrastructure and water supply costs for residents.

Aquifer storage and recovery can provide a useful means of developing new water reso urces at a competitive price and enables m ore efficient use of all water resources in urban and suburban

Groundwater Studies R eport No. 63, Nov 1995 .

Dillon, P.J and Pavelic, P (1996) Guidelines for the quali ty of stormwater and treated wastewa ter for inj ection into aquifers for storage and reuse . Urban Water Research Assoc. of Australia , R esearch Report No 109 .

Dillon , P.J., Pavelic, P. , Ge rges, N.Z., Armstrong, D. , and Emmett, A.J. (1995) Stormwater inj ec tion effects on groundwater quali ty in South Australia. Proc.

2nd In t. Symp. on Artific ial R echarge of Groundwater, Florida, July 1994, Am. Soc . Civil Eng. New York , p 426- 435.

Gerges N. Z., Si benaler, X .P . and H owles, S.R. (1996) South Australian experie nce in aquifer storage and recovery. Proc. Int. Symp . on Artific ial R ec harge of Groundwater, H elsinki , Finland , 3-5 Jun e 1996.

Gerges, N .Z. (1996) Proposals for injectin g efflu ent fo r aq uife r storage and recovery sc hem e. Proc. Int. Symp. Artificial R ec harge of G roundwater, H elsinki , June 1996.

No rdic H ydrologic Programme NHP R eport No 38, pp.

65-73.

Ge rges, N.Z. , Sibena ler, X .P . and Armstrong, D. (1995) Experience 111 inj ec ting stormwater into aquifers to en hance irrigation water suppli es in South Australia. Proc. 2nd Int. Symp. on Artificial R ec harge of Groundwa ter, Florida , July 1994, Am. Soc. Civil Eng. ·New York, p. 436-445.

Gerges, N.Z ., Sibenaler, X .P. , and H owles,

S.R. (1996) South Australian experience in aquifer storage and recove ry. Proc. Int. Sym p.

Artificial R ec harge of Groundwater, H elsinki, Ju ne 1996 .

Nordic H ydro logic Programme N HP R eport No 38, p75-83 .

H ekmeijer, P. (1997) Evaluation of injection well clogging at Andrews Farm, South Australia. MSc Thesis, School of Earth Sciences , Flinders University of SA. K.inhill Metcalf and Eddy (1996) Virgi nia Pipeline Scheme Trea ted Water Study.

Draft Final R eport to MFP Australia, June 1996.

National Water· Qua li ty Management Strategy (1992) Australian water quali ty guidelines fo r fres h and marine wa ters .

ANZECC, Ca nberra.

Pavelic, P. and Dillon, P.J. (1996) T he impac t of two seasons of stormwater inj ection on groundwater quali ty in South Australia. Proc. Intl. Symp.

Artificial R echarge of Gro und wa ter, H elsinki, J une 1996. Nordic Hydrologic Progra mme N HP Report No 38, p105-110 .

Pavelic, P. , D illon, P.J. , Ragu sa , S.R . and T oze, S. (1996) The fa te and transport of mi croorganisms introd uced to groundwa ter through wastewater reclamation.

Centre for Groundwater Studies Report No 69 .

Pavelic, P. , Ragusa , S., Flower, R.L. , RinckPfeiffer, S.M. and Dillon, P.J. (1997) Diffu sion chamber method fo r in situ meas urement of pathogen inactiva tion in groundwater. Water R esearch (submitted).

Rattray, K.J. , H erczeg, 'A.L. , Dillon, P.J. and Pavelic, P. (1996) Geochemi cal process in aquifers receiving injected stormwater.

Centre for Groundwater Studies R eport No 65.

Sinclair Knight M erz (1996) Mosman Park Sewe r Mining and Effluent R euse Proj ec t. Draft Feasibili ty R eport to W .A. Wa ter Corpo ratio n, April 1996.

Stevens, R .L. , Emmett, A.J., and Howles, S.R. (1995) Stormwa ter reuse at R egent Ga rdens residential development, Northfield, South Austra lia. Proc 2nd In tl. Symp . on Urba n Stormwa ter Management, M elbourne, July 1995.

T elfer, A. (1995) 100 years of stormwa ter rec harge : Mount Ga mbier, South Au stralia. Proc. 2nd In t. Symp . on Artifi cial R ec harge of Gro un dwa ter, Florida, July 1994, Am. Soc. Civil Eng. New York, p 732-741.

Authors Peter DIiion and Paul Pavellc are R esearch Scientists in the water reclamation project of CSIRO Land and Water and the Centre for Gro undwater Studies, PMB 2, Glen Osmond, SA 5064.

Xavier Slbenaler and Nabil Gerges are Senior H ydrogeologists in the Division of Groundwater and Environmental R esources ofMin es and En ergy, SA .

Richard Clark is a Manager of Water R eform in th e Water R eso urces Gro up of th e D epartm ent of Envfronment and Natural R esources, SA. This team has been researching ASR since 1991, under the mpervision of th e SA Artificial R echarge Coordin ating Committee . The first Australian ASR Workshop was conducted by th e Centre for Gro undwater Studies in Adelaide in October 1996.

WATER JULY/ AUGUST 1997

11

WOMEN IN WATER

MAKE A SPLASH Therese Flapper, Annalisa Dixon

Therese Flapper with husband John O'Keefe

Water has existed since the dawn of the planet. We can think of the water industry as having begun when Homo sapiens started using it for their benefit and developing technology to manage it. This technology slowly evolved into sophisticated systems of agriculture, water storage, water supply and waste water handling. Adam and Eve have also been around since the dawn of the planet, at least according to one account! Let's assume this hypothesis for now in any case. The water industry, and Adam and Eve, have evolved through time and progressed.

T he industry can produce po table wa ter fro m sewage, re use sludge in agriculture, store water fo r ideal use, generate electricity, minimi se wa ter usage and m anage the wa ter cycle.

Adam and Eve can eat any apple they want, live and work w here they want, have children w hen they choose and even leave each o ther if they wish .

Yet thro ugho ut this evolu tionary process Adam seems to have dominated the water industry w hile Eve continued to sit in the garden and play with the devil! Underpinning this evolutio nary path is the tradition of M an as provider and W oman as homemaker. T here is no point in questioning that traditio neven theorising about it can be seen as was ted energy-bu t a co nce ntrated effort needs to be made to di rect the evolutionary path into a more equitable fut ure.

Since the sexual revolutio n in the 1960s Eve has wanted to play a different role. In today's society this concept is som ewhat accepted. Eve goes to university and completes science, engineering and other degrees . She maintains fulltime employment. She can progress in her chosen fi eld to an extent. But in the water industry she re mains underreprese nted in functions that are o utside the doma in of the day- to-day workpl ace. A nd she is under-represen ted in associations that serve the water industry such as the AWWA .

In summary, Eve does no t profile in the greater domain of the water industry in the sa me way that Adam does .

WIW Interest Group These concepts are the basis of w hy AWWA's N ew South W ales Branch has fo unded a W omen in W ater (WIW) interest group , w hi ch held its inaugural workshop in O ctober 1996, followed by a workshop in April 1997.

The aims, obj ectives and activities of WIW were discussed at these mee tings, and a program designed to pave the future evolutio nary path fo r w omen in the water industry has begun.

The main aim ofWIW is to promote and improve the role of wom en in all as pec ts of the water indu stry. The obj ectives of the group relate to the prac ticali ty of achieving this aim. They include: • increasing the proportion of women members in AWW A • pro mo ting the activities of AWWA women members in the water industry • improving the contribution rate of women both within AWWA and the water secto r • creating opportunities where women can participate in the industry • increasing the acceptance of women in the water sector as capable contributo rs at technical, m anagerial and business functio n levels • improving women 's progression to high levels within organisatio ns, the water sector and AWWA • reducing the rate of attritio n of women from the wa ter secto r.

WIW decided not o nly to targe t engineers and scientists, even though these disciplines constitute the majority

Annallsa Dixon

of current AWWA members and wa ter sector professionals. W e also want to consider human resource manage rs, planners, economists, policy developers, m arketing and communicatio ns personnel and support staff The reason for this is to bette~ refle ct the active components of the water sector and to better encompass the contribution of women in the water-related workfo rce.

T he WIW interest group is active via seminars, workshop s and articles in N ewsdrop, Crosscurrent and Water.

The group is no t designed as a 'wom en only' group but is designed to 'She's aggressive, provide o pphe's dynamic; ortunities for she's stuck-up, w omen and he's confident; men to network o n a proshe's power mad, fessio nal basis. he exercises A sec ondary authority dlllgently' but important

- Leonie St/II design obj ective is to allow women to demo nstrate their skills as techni cally capable contributors.

Greater participation and exposure will result in recognition and empowerment of our fe male colleagues.

Plans for Women in Water W e recently held the second WIW half-day workshop and this year it was sponsored by Sydney W at er.

Participants ranged from executives to students in fi elds as diverse as research , accounting, business develop-

'If there is to be a major shift In the direction our corporate world Is heading, then It must come from women taking leadership' - Diane Mccann 12

WATER JULY/ AUGUST 1997

WOMEN

IN

WATER

m ent , scien ce and process engm ee nng.

Judith M eeske of Sydney W ater discussed the recently launched Flexible W ork Prac tices Kit w hich is aimed at addressing the issues of wom en' s career development , work and fa mily commitments, part-time and fl exible working arrangements, Participants at the Inaugural WIW workshop attitudes towards wom en in the workplace and commuAs well as these activities, a number nication between women and manageof directives will be ac tively addressed , ment. including valuing mo re highly the The works hop developed a fo rmal commo nly viewed 'female' attributes . set of ac tio ns for the interest group su ch as communi ca tio n and client w hich will be steadily implemented relations, organisa tional ability, proj ect thro ugh time including: management and delivery skills and the • organising quarterly W ater Drinks ability to cope with a wider range of for wom en and m en me mb ers of tasks at o nce . Other fa ctors to be AWWA con sidered will include fl exible • developing an AWW A positio n working conditions, positive pro mopaper on standard working conditions tion , equal pay and packages, maternity and w ork practices for the water leave and paternal as well as maternal industry co n sideratio n , the development of • raising the profile of women thro ugh nego tiation skills, organisational structhe various AWWA media • increasing the participati o n of ture review and increasing the comfort wom en at AWW A co nferences and of wom en by reassessing the pub/snoo ker/golf course bu siness fun ctions circuit.

• fo rming a WIW database.

WIW wants to improve the prospects and contribution of wom en in the water industry. T hi s will no t only benefit wo men .

T he wa ter industry is striving to provid e grea ter standards of service to the community . T he grea ter involvement of women will-produced inspired, enthu siastic ideas that are set apart from the 'conventional wisdom' syndrome of the Adam era.

If yo u have any comments, want to become involved or sponsor Women in W ater activities, want to be listed on the WIW database, want any more details or want to make a contribution, contact the authors.

Authors Therese Flapper is a PhD studen t in environmental m icrobiology at th e University of NSW. Sh e has been active in A WWA for five years and works as an Environmental Scientist with CH2M HILL, Level 16, 111 Pacific H wy, North Sydney NSW 2060, tel. 015 901 378.

Annalisa Dixon is a Chemical Engineer currendy working in business developmen t with En vironm ental Systems, 9 Packard A venue, Castle Hill f'!SW 2154, tel. (02) 9899 3499.

Interesting Facts • Women represent 10% of AWWA 's federal membership.

• Twelve per cent of AWWA's NSW Branch members are women.

• Three hundred men and only ten women have won the Nobel Prize for Science since its inception in 1901.

• The Sydney Water gold medal has only just been awarded to a woman for the first time.

• AWWA has numerous awards such as the George Goffin, Guy Parker, Michael Flynn, Peter Hughes Awards, as well as life membership. Few women have received these awards.

• AWWA has never had a female federal president (IEAust and RACI do have female presidents, after having taskgroups for women).

• In science and engineerin g women earn 20% less than men for the same level of work and experience.

• Sydney Water has a much lower level of female employees (19.2%) than the overall workforce (43 %).

Only 12% of those earning more than $40,000 are women.

PROCESS EQUIPMENT .Warman belt press filters, centrifuges, purifiers and belt/drum thickeners offer: • superior performance • competitive pricing • skilled technical support • equipment for every type and size installation • product reliability • national sales and service.

Every product is backed by the Warman reputation for delivering high performance equipment with lower ownership costs.

Talk to the experts. Contact Stephen Price and his team in Sydney on (02) 9934 5100 or Mark Morrow in Perth on (09) 277 4166 Warman International Ltd. Regional offices throughout Australia and New Zealand

WATER JULY/ AUGUST 1997

13

WASTEWATER

A STRATEGIC REVIEW OF THE WATER TREATMENT INDUSTRY D Bainbridge Abstract Australia's water supply authorities are undergoing radical internal change that is being driven by Australia's National Competition Policy. T hese .changes coincide with the emergence of an important strategic position in the global water market as water becomes one of the international issues of the next centu ry. T he opportuni ty exists for Australia to gain a share of an international wa ter trea tment market that will become increasingly impo rtant with expected growth in populations and affluence over the next 50 years.

Australia's water authorities have a special role to play in adopting a coordi nated approach to the development of an internationally competitive water indu stry. However, they first must redefine their situations and recognise that they share with the rest of the world the emerging water supply problem .

Role of Utilities Australia's Competitio n Policy is an agreement between the Federal and State governme nts that recognises that inefficiencies in government bureaucracies create a cost drag on those sectors of the economy that compete in the global market.

Utilities suppl ying telecommunications, power, water and gas have been a major target for reform that aims to reduce utility cos ts. Utilities collectively represent a larger share of the Australian economy than the agricultural or mining industries. The water and drainage industry itself represented $4. 1 billi on of Au stralia's Gross Domestic Product in 1995-96.

Being a competitive economy involves more than low costs . The most successful international eco nomies have skills in particular indu stries that give them competitive advantage. By improving living standards, competitive advantage actualJy increases the cost levels of an economy. Developing the expertise that leads to competitive adva ntage relies on a co mbination of factors in the domestic market, including a demanding group of customers, high expectation, a pool oflocal expertise and competition among local firms 14

WATER JULY/ AUGUST 1997

that encourages the development of new and better ways of doing things.

Innovation is an essential element of competi tive advantage.

There has been much comment that Australian indu stry is at a disadva ntage because of a small domestic marke t.

Other economies have shown that, if a product is good enough, the global market is there, irrespective of the size of the local market. Australia has the skills, but is short of segments in the economy aro und w hich a critical mass of skilJs can cluster to create competitive advantage. Any sector of the economy that has the scale to support this clustering of skills needs to be regarded as a valuable national asse t.

Utilities are amo ng th e few sectors that have scale in Australia's econom.y.

In contrast to other OECD countries, utilities dominate any listing of Australi a's major indu stries. T hi s reflects the thinness of Au stralian indu stry and the fact that utilities provide basic infrastructure to a smalJ population over large geographic areas.

The relative size of utilities in the Australian economy should alert us to th e potential for Australia to have special competencies in these industries and in the industries that supply them.

It also means that the way in which utiliti es apply and acquire technology is m uch more important in the Australian economy than in other economies. T he positive role that Australia's utilities can play in the development of national compe titiveness has been buried by a preoccupation with cost efficiency.

Turning Expertise into Competitive Advantage The cultures and practices of Australia's water authorities have not supported the development of a strong local water industry. T hro ughout most of their history wa ter authorities have been conservative in their choice of technology, and have retained design and construction of facilities inhou se.

In co ntra st, Telecom long ago recognised that its attempts to be the sole provider of equipment u sed on its network were hindering the adoption of new technology. Telecom gave up control over the design of telecommu-

nications equipment. 'As a result, over many years Telecom supported the development of a local telecommunications equipment indu stry that has been a major co ntributor to th e recent growth in Au stralia's manufa ctured exports.

The Sustainable E nergy Development Authority (SEDA) sponsored a deal with power utilities that has the effect of encouraging local technology development in the power industry.

Under the SEDA agreement power utilities agree to promote 'green' electricity at slightly higher prices to interested customers. Utili ties will buy thi s electricity from green suppli ers w h o use w ind or solar p ower or reclaimed gases from landfills. T here is no certainty abou t how the scheme will shape up, but as a result of uti lities agreeing to give up control of the technology to be used for part of their supply, it provides a market for developers of non-pollu ting power technology. Because economics heavily favour coal, this provides an incentive fo r creative thinking to achieve technological brea kthroughs that will be necessary if alternative power sources are to challenge coal in the real market.

Common elements in crea tin g competitive advantage are the encouragement of new ideas, often from small operators. Australian water authorities have operated at the opposite end of the scale. When competitive and environmental pressures forced authorities to shift to external tendering of contracts in recent years, in the absence of a well structured local industry, the major contra cts have go ne to British, French and US groups. The results of these tenders indicate that these Australian water authorities are not comfortable with innovation, preferring established technology and organisatio ns equivalent in size to themselves .

industry Strategic Position Popu lation growth is the single most important determinant of the water industry's strategic position. In 1800, as world population approached 1 billion, Malthus had just published his theory that the population exp losion would outgrow the food supply. Since then,

WASTEWATER technology ha s expanded an the resources needed by human beings, with the exception of rainfall. The real population explosion began a century and a half after his prediction. From a base of 2.5 billion in 1950 , wo rld population will increase by almo st 4 billion by 2000 and by a similar number in the follo wing 50 years. W o rld populati on growth is expected to taper off to stabilise at 11. 6 billion in 2200.

Figure 1 shows that Australian population has grow n at the same rate as world population since 1850.

T here are signs in many parts of the world that the population increase of the las t 50 years has taken up the slack in natural sources of water. The flip side . of this is that there is growing disquiet about the environmental effec t of the di sp osal of increasing volumes of wastewater. Because water is an essential ingredient in the drinking supply and in fo od productio n , a similar populatio n increase in the next 50 years will require technology to make water w ork h arder to fulfil these nee ds.

T echnology used in the wa ter industry to date has been relatively simple. A technological leap will be required , providing an opportunity for innovation and the achievement of competitive advantage.

Australia has the expertise to take advantage of the emerging opportunities. Australian engineers designed a water treatment plant that extrac ts drinking wa ter fro m Bangko k's polluted canals. Australian equipment is being used to filter drinking water supplies in Asia, Europe and the US. What Australia needs is maj or operators in th e h om e market w ho are willing to expand their fo cus beyond their internal problem s, w h o are prepared to dem onstrate trust in the local industry and who are willing to provide pati en t support fo r local innovatio n , particularly by sm all operators.

a solution to a disadvantage . If natural advantage gen erated co mpetltlve advantage, Au stralia wo uld have a thriving woollen textile industry. It was the absence of natural resources that made the Japanese realise they had to u se their large and disciplined workfo rce to create competitive advantage by adding value to other people's natural resources. Ano ther example of turning di sadvantage into competitive advantage was facs imil e technology, w hi ch deve lo ped in Japan becau se Japanese text was diffic ult to reproduce electronically. The essential elements are to recognise a need, and to have the skills to develop a solution .

Australia's disadvantages in relation to water place it in an ideal position to d velop competitive advantage in water treatment. Australia is a dry continent with the m ost extreme variations in rainfall on the planet.1 The low or nonexistent flow in Australia's rivers affects availability of drinking water as well as quality, because of the concentration of contaminants. Au stralia's waterways are unforgiving, and the technology fo r separation of contaminants is critical.

In m any respects Au strali a is in denial about its wa ter disadvantages.

Extended dro ughts followed by floods are not bad luck ; they are a normal part of our extrem e climatic oscillations.

Urban water supply authorities have insulated their residents from reality by draining water from large trac ts of land to supply a relatively small population.

T he following analysis de m o nstrates that difficulties in Sydney's wa ter and drainage sys tem s are a microcosm of w hat is happening througho ut the world.

Sydney-A Case Study

Sydney draws its water from a ca tchment of almost 10,000 square kilometres w hich strips most of the natural flow from the Nepean River sys tem.

This is supplem ented from the Shoalhaven River fu rther to the south , Turning Disadvantage into w hich has a catchment of 5,600 square Competitive Advantage kilometres . The large catchment is The mo st co mmon so urce of needed because of the low runoff. Large competitive advantage is the creation of dam storage is needed because of the variability of rainfa ll , w ith the ca tchment Austra lia World regularly expen encm g (Bi llions) Population Growth {Millions) droughts that last fo r 30 10 All th ese years.

25 resources are comn1it20 O World - left scale ted to passing 1,200 million litres of water a t Australia - right scale 15 day thro ugh Sydney 10 and W ollo ngo ng, discharging 90% of it into the ocean with 0 2050 2000 1950 1900 1800 1850 1750 Year minimal treatment and 6. the rest into the Figure 1 Austra lian and world popu lation growth 1850 -2050 N epean River after SOURCES : UNITED NATIONS POPUlATlON DIV ISIOM

BUREAU OF STATISTICS

tertiary trea tment, providing m uch of that river's fl ow.

The strategy determined a century ago fo r Sydney's water system was to draw wa ter from a clea n natural environment, use it on ce , th en use gravity w here possible to drain it through passive infrast ructure to an ocean o utfall. In 1900 the sewer mains to the fi rst outfall at Bondi ran thro ugh deserted sand du nes. By 1930 Bondi was fully developed, and a new surf cultu re was attracti t g massive crowds to smf in the waters in w hi ch their effluent was discharged . As Sydney's populatio n grew, thi s sys tem was extended and repeated. Today's system drains hu ge geographic areas to fo ur maj or ocea n o utfalls. Growing protests aga inst beac h polluti on res ul ted in extensions of the syste m during the pas t decade to deep ocean o utfall s several kilo metres offshore.

T he newly co rpo ratise d Sydn ey Water has identified the overfl ow of raw sewage in to wate rways during heavy rain as its maj or challenge. Wet wea ther overflows occur 17 times a year across the 80% of the system w hi ch drains to the Sydn ey ocean o utfall s.

Sydney W ater estima tes that rec tification of the 3000 overfl ow points across the whole system will cost between S2 billion and $5 billion.

Sydney W ater attributes these overflows to infiltration of rainwater.

Given that infiltra tion is a problem fo r systems worldwide, the true cause of th e problem has been the extension of the system well beyond its capacity, w hich was probably reached some time during the 1960s. Minor infiltratio ns across an overextended network make overflows inevitable. Syd ney's wate r authorities continued to u se a 19th century strategy for 30-40 years after it had reached its limi ts .

Innovation arises from solving difficult problems, but first the problem has to be recogni se d . M oving efflu ent across tow n to dump it in the ocean has been the easy option fo r Sydney's wa ter authorities . Instead of recognising the drainage network as the problem , they have treated it as the solution .

Another problem that has no t been ide ntified by Sydney Wa ter has been the extent to w hich it has retained control over the technology used in its inland treatment plants, resulting in an ins ular perspective on the design and operation of the plants. M embers of the local water industry regarp those trea tment plants as ineffi cient and dated.

Studies by Sydney W ater have shown that the level of treatment of effluent in its inland plants is inadeq uate fo r discharge into a river stripped of fl ow, res ulting in toxic algal blooms and o ther environmental problems.

WATER JULY/ AUGUST 1997

15

WASTEWATER Arguments for Reuse Sydney Water has now expressed its long-term commitment to recycling.

R euse has the potential to indefinitely defer the construction of another large dam on the Shoalhaven River and to take load off the drainage network , reducing the risk of overflows during rain. Sydney Water studies show that the extra treatment of water discharged to the N epean River needed to remove algal blooms will produce water of nonpotable recycling standard. The extra cost of installing a dual delivery system for non-potable water makes it economic to treat to a level suitable for direc t recycling as potable water.

Sydney Water's experience with the non- potable recycling plant at Rouse Hill has bee n that the processes needed to bring water up to the standard for non-potable recycling w ill produce potable water.

Each higher level of treatment makes the next level of treatment economically sustainable. R euse is a 100% / zero gam e. The economically sensible options are to minimise trea tment, as happens through the outfalls, or to fully treat for potable reuse.

Sydney W ater faces the same imperatives that the world faces, with Sydney's population proj ec ted to reach six million by 2020. One sensible scenario is for sections of the drainage network to be progressively turned over for recycling, gradually reducing the volume draining to the outfalls.

A Question of Scale Sydney W ater plans to decentralise processing from the ocean outfalls and to centralise the inland trea tment plants to achieve economies of scale. The structure of the system hinges on the question of the economi c scale for trea tment plants . Internal studies by Sydney Water are reported to favour a minimum size of 25,000 eq uivalent population (EP). Other engineers claim that a plant can be designed to be economic for 5,000 EP. A parallel exists in steel making in which large blast furnaces located near energy sources provide unquestioned scale economies. Despite this, BHP constructed a mini mill in Rooty Hill , on the outskirts of Sydney, with its economics based on proximity to the source of car bodies w hich are its feed, and to economical transport routes for deliveries to its customers th ro ughout Australia . BHP sacrificed scale for location. Smaller scale has improved respon siveness and fl exibility, with production cycles red uced to fo ur weeks, compared to 13 weeks for the blast furnace . BHP's anno uncement of the closure of the Newcastle blast 16

WATER JULY/ AUGUST 1997

furnaces was precipitated by the shift in the steel industry towards new, less capital-intensive technology. BHP's strategy has shifted to producing iron billets in Port H edland , using the proximity of iron ore supplies to North W est shelf gas. These iron billets, which co uld be describ ed as 92% of the refined steel, will be shipped to mills loca ted close to markets in various countries, where they will be used as the raw material to produce steel in the form required by those markets. 3 Studies comparing the performances of organisations of different sizes indicate that theoretical advantages of scale can be confounded in practice by human , market and logistical fac tors. 4 Smaller units are more responsive to changes in volume and market requirements. An effective way of handling a large problem is to brea k it into manageable blocks. It is the large scale of flows to the fo ur ocean o utfalls which become unmanageable during rain, overflowing an average of 17 times per year. The smaller syste ms draining to the inland plants ave rage only one overflow per year.

The critical issue is the total cost across the sys tem , n ot just sca le efficiency at the point of processing.

R ecycling changes the economics of water treatment, beca use the source of effluent and the market for treated water coincide.

Bangkok water authorities decided to extrac t wa ter from canals w hich contain everything yo u could imagine might be there. This decision was not made because of a la ck of alternatives.

Bangkok is in the monsoonal zone and has the opposite problem to Sydney, an excess of water. Instead of installing infrastructure to move water from a cleaner source th ro ugh their densely populated urban areas , it made se nse to use technology to extract water from a source of water located w here the demand was.

The logic of treating water onsite will becom e increasingly relevant in Sydney and elsewhere as natural sources of clean drinking wa ter becom e scarcer, and as more stringent standards for discharge to the environment improve the economics of recycling.

Blueprint for the Future T he chall enge is to enco urage a combinatio n of factors in the Australian water industry to support innovation to reduce processing cos ts. This would improve the economics of recycling w hile providing an opportunity for achieving competitive advantage .

The problems in Sydney' s water system are the result of linear thinking.

What is needed is a lateral approach no t restricted by preconceptions . The

ultimate solution will be a combination of structure and technology. The following model is not presented as the solution , but as a structure that fits the logistics of recycling in which appropriate technology can be developed.

The core of this model is a smaller, decentralised plant whose location is defin ed by the drainage catchment and can be installed locally in a small area, perhaps underneath a playing field or park. The processes used in these small plants could be determined by the abili ty to remotely monitor and control them. T hey co uld deliver partially treated water (92% water) to a larger facility located with access to the reticulation system. That facility could apply the final processes and quali ty controls before recycling water back into the local drinking supply . The existence of these facilities within a catchment could even tu ally replace the present centralised water filtration plants.

R eticulation and recycling ca tchments could become separate business units fo r the purpose of monitoring the perfo rmance of water trea tment system s. An advantage of in-catchment treatment is the opportunity to separate domes tic, industrial and co mmercial efflu ents for different methods of trea tment w here appropriate.

There could be a largely se lf contained water cycle within the catchment. External connec tion s wo uld include fresh water brought in from the authority, and effluent not fully treated in the catchment passed o n for trea tm en t in a central plant prio r to di sc harge to the environment.

Conceptually, the process in the catchment could represent water mining, the removal of wa ter from the effluent, rather than trea tment, which aims to remove impurities from the water. This conceptual difference might allow cheaper processes to be used in the ca tchment, wi th different processes used in larger central plants. In this way it may be possible to achieve the advantages of both loca tion and scale.

Initially Australian water authorities could construct a number of trial installations, based on proposals for alternative designs from the Australian water indu stry. Because treatment involves multiple processes, these proposals should allow for a number of suppliers to make up each consortium.

T here is obvious poten tial for opera ting indivi dual catchments as separa te business units, ,w hich has the adva ntage of allowing comparison of performance. There is also potential for contracting the management of individual ca tchments, encouraging compe titi on and innova tion. In co ntras t, contracting out the whole system, or a large part of it, to one opera tor has the

WASTEWATER potential to p erpetuate the ' natural monopoly' syndrome.

Conclusion National comp etitive adva ntage arises from the intelligent use of a nation's skills to find better ways of dealing with a problem. An important component of competitive advantage is innovation, driven by the need to find a solution to a disadvantage. Innovation requires a clustering of skills and intellec tual en ergy . Publi c utilities are among the few sectors of the Australian eco nomy that provide critical mass aro und w hich skills and intellec tual energy can cluster. T his places a special responsibility on Australian utilities to . use their purchasing of technology intelligently to promote the developm ent of competitive indu stri es in Australia.

This argument appli es particularly to water utilities, becau se the water industry is at a critical strategic stage, both wo rldwide and in Au stralia . W orld problem s relating to the supply of water and treatment of was te have bee n driven by population increase over the past 50 years that is one and a half times the growth in the previous two million years of human existence on this planet.

That growth will be repeated over the next 50 years, creating both an urgent need and a window of opportunity.

Australia's population growth has matched that of the world , and it shares the world's water problems. In addi tion, Au stralia suffers special disadvantages that make improved water technology fundamental to its long-term economic and social health. It is those technology improvem ents that will crea te the opportunities for achieving competitive advantage .

Australi a is ideally positioned to becom e a supplier of innova tive products to an international water market increasing in size and sophistication. Instead, Australia's key water authorities, internally foc used on their own problems, have made Australia a cu stomer for es tablished technology from fore ign suppliers . The sm art option for a clever country would be to en courage local innovation and the development of an export industry.

T he past practice of water authorities of retaining control of their technology in-house, w hich has long operated to the detriment of a local water industry, is a hallmark of a bureaucracy. So is the ca uti on that led th em to take the conserva tive option to buy established technology from overseas suppliers.

That approach may be low risk for the authorities in the short term, but it is high risk for the Australian economy in the long term. The risk is that we will make the acquisition of water technol-

ogy a net cost to. the community instead of a generator of wealth and employm ent for Australians . The risk is that we waste another market opportunity and make ourselves a useful test bed for foreign suppliers to gain experience in the international market.

What is needed to support the development of an internationally competitive water indu stry is a change in the process by which our water authorities acquire their technology. Water authorities need to become supportive but demanding customers, perhaps through a nationally coordinated research program . A willingness to relinquish a measure of control of the technology to be used will involve cultural change on the part of the wate r authorities.

However, this will complement their current efforts to reform themselves, and they will retain ultimate control through compliance testing of water distributed to custom ers or released into the environment.

Endnotes 1.

Diamond , J from a Science Show broadcast on Radio National on 20 January 1997 of a paper to the ANZAAS Congress in Canberra on the effect of enso-driven climatic oscillations on civilisa ti ons throughout history. Prof.

Diamond described Austra lia as the extreme outli er in relation to climatic

oscillati on, the only co ntinen t w here variations are more extreme between yea rs than between seasons.

2. Information from Sydney W ater's 1996 Environment R eport and its 1997 submission to the Inquiry into Manageme nt of Sewage and Sewage Byproducts in the Coastal Zone plus interviews with Sydney Water staff and external engineers.

3. Comments on BHP's strategic decisionmaking in the steel industry are based on BHP press releases and interviews with Steel and Minerals division executives.

4. Mathews, J c;;ompeting Paradigms of Productive Efficiency: Indu strial R elation s and Organi sa tional Change, Australian Grad uate School of Management, 1993 .

T his paper , presented to the Conference on Theory and Practice of Industrial Culture in Bremen , Germa ny, describes a shift away from large-scale, standardised processing with centralised control and a foc us on capital equipment towards systems emphasising quality, flexibili ty, personal and tea m com1nitmen t, foc using on people and their use of technology.

Author David Bainbridge, ACA, MBA (Syd), is the principal of Bainbridge Associates, advisors on competitive behaviour, purchasing and tendering practice, and optimisation of internal system s. Contact details are 115 D over Rd, R ose Bay NSW 2029, tel. (02) 9371 7704, fax (02) , 9371 8004, em ail bassoc@ozemail.com. au

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~IRONMENllll CONSULTING ENVIRONMENTAL ENGINEERS & SCIENTISTS Offices throughout Australia and South East Asia WATER JULY/ AUGUST 1997

17

WASTEWATER

POWER GENERATI '

Abstract In 1992 M elbourne W ater installed a huge floating cover over the anaero bic stage of one of its sewage treatment lagoons at the W estern Treatment Plant at W erribee, Victoria . This was done primarily to reduce the odour from anaerobic fermentation, but use of the biogas for power production was always envisaged.

In 1994 a contract was let to Sinclair Knight M erz for design and construction management of a suitable electricity generating plant. T he plant was commissioned in 1996 and incorporates chemical-free gas scrubbing equipment, gas preheating, and two 632 KW sparkignition reciprocating gas engines.

Key Words Biogas, power generation, lagoon , wastewater treatment

Introduction M elbourne , now a city of some three million people, operates an unusual wastewater trea tment plant . The W es tern Treatment Plant currently deals with some 500 ML/d of fairly conce ntrated was tewa ter from th e western half of M elbourne w here the bulk of indu stry is situ ated . This includes some large noxious trades. T he plant occupies 11 000 ha of flat land

A longer version of this pap er was presented at the 17th A WWA Federal Con vention (see th e Proceedings document for forth er m echanical and electrical details). abutting Port Phillip Bay, some 30 km south-wes t of the city , and uses a combination of land irriga tion and grass filt ra tio n , but predo minantly large lagoons.

When originally conceived , the area surrounding the plant was inhabited only by agriculturists, but the city has expanded to the point where housing encroac hes into w hat was once an adequate bu ffe r zone. M elbourne W ater mounted an attack on odour generation w hich was reported in Water (Gulovsen et al. , 1992). Among the initiatives was the installation of a 3.3 ha floating cover over the first stage of one of the major lagoo ns, and m echanical aeration of the second stage.

It was always envisaged that th e biogas generated by anaerobic activity under the cover would be used for power generation, although initially the gas flow was monitored and flared.

In 1994, contracts were let for design and construction of a suitable power generation plant and a power plant has bee n operated successfull y since February 1996.

Lagoon Operation The treatment lagoons consist of a series of elongated ponds , where aeration is achieved by wind and wave action in their exposed situation along the coast.

Lagoon 115E comprises 11 ponds in series, the first two ponds being 3 m deep, the remainder 2 m deep. The first pond is 150 m wide and 1 km long.

Succeeding ponds extend in length to some 1.5 km.

Pond 1 was fed with raw sewage, and the first 200-300 111 developed a thick scum of grease, fibrous material and litter, which erupted spasmodically as ana erobic fermentation took place benea th it. Beyond that, the clearer liquor was still highly anaerobic , and generated significant odour.

T he first odour-reduction initiative was to install floating aerators on the further reaches of Pond 1 and in Pond 2. These were specially designed to maintain 2 mg/L DO on the surface but retain the facultative action below.

The second initiative was to install a floating cover over the first 220 111 of Pond 1 so that the anaerobic activity could be enhanced in this zone and the odorous gases trapped.

The cover, which measured 230 m x 150 m or 3.3 ha , was made of 2.5 mm HDPE sheet and heat-welded on-site.

WATER JULY/AUGUST 1997

19

WASTEWATER Further details of the design , including the reinforcement, ballast pipes and exit curtain are reported in Gulovsen et al., 1992.

The cover has operated successfully since it was installed in 1992, and has withstood the coastal weather conditions. A few ruptures have bee n successfu ll y repaired. When fir st in stalled it was planned to maintain a slight vacuum beneath the cover by external fans, but it was been fo und that storage of a day's gas production is perfec tly feasible. However, under high wind conditions reduction of the profile is advisable.

The incoming raw sewage of approximately 60 ML/d has a BOD of ¡ 450- 500 mg/L due to the trade waste component. Monitoring the outflow from beneath the curtain shows that anaerobic activity reduces the BOD to 150-180 mg/L, i. e. some 18 000 kg per day being decomposed.

It was estimated that the resultant biogas would average 10,000 m 3 per day. T he gas was initially monitored, and its composition was analysed and flared until the power generation plant was installed.

The Power Plant The power generation faci lity at 115E Lagoon was designed by Sinclair Knight Merz to use daily gas productions of bet\veen 7200 m 3/day (winter) and 10 800 m 3/day (summer) from lagoon was tewater inflows of 60 ML/day. The intended mode of operation was to run the generators only during electricity supply peak ho urs (7.00 am to 11 .00 pm weekdays) , using th e eight-hour overnight off-peak peri od to store gas under the floating cover. This enables flows of 10,800 to 16,200 m 3/day (450 to 675 3m /hr) to be handled over the 16-hour peak periods.

T he t\Vo generating sets are each rated at 632 kW electrical output. The sets are sized to handle winter gas flows , the expec tatio n being that fl aring of excess gas will be required in summer.

At a maximum load of 632 kW each gas engin e consum es approximately 240 111 3/hr of biogas (referenc e conditions 101.3 kPa and 60% relative humidity).

T he purpose of the generating plant is to redu ce M elbourne W ater's power Table 1 Lagoon gas compos ition Methane Oxyge n & argon Nitrogen Carbon Dioxide Carbon Monoxide Hydroge n Sulphid e Lower Calorific Value

20

(% v/v) (% v/v) (% v/v) (% v/v)

85.0 0.2 5.5

9.3

(ppm v/ v) 10.5 (ppm v/ v) 1000-4000 ppm ma x (LCV) = 25 MJ/ m3 (ca lcu lated)

WATER JULY/ AUGUST 1997

bills for the aerators and the plant runs only when the 22 kV power line is energised from the Powerco r zone substa tion. The generators were not designed to have emergency standby function due to the considerable extra cost involved, and the availability of grid power. Since competition was introduced into the Victorian electricity supply industry, unit costs of off-peak electricity have risen to over 2.5 cents/kWh. It is probable that, in the future, generation in off-peak hours will be preferred . Gas is often stored under the cover at weekends, during winter rather than flaring.

T he two 632 kW genera tors are driven by induced-draught spark ignition, reciprocating gas engines w hich operate at a thermal efficiency exceeding 37% . The se ts generate power at 415 volts which is transformed on-site to 22 kilovolts and conveyed to existing substations, from w hich power is provided fo r aera tion systems on three sewage treatment lagoons. Although the genera ting sets run in synchronism with the Powercor 22 kV supply, this is to facilitate tra nsport of power to the other lagoons at 22 kV. There is in sufficient generation to allow export into the Powercor distribution system.

T he lagoon gas is provided to the gas engines at regulated pressure by mean s of a variable speed centrifugal blower.

The gas has a higher methane content than most landfill gas and digester gas. It typical composition is as shown in Table 1.

need for gas compression equipment.

The latter produces a significant saving in capital cost and maintenance.

The engines currently employ an acid-resistant lubricating oil (Caltex Geostar) w hich has recently been developed for biogas applications and which allows 1000 hours of operation bet\Veen oil changes.

Engine governor control is provided by a Heinzmann Si-T ee Co-Generation Control (CGC) unit mounted on the genset control cubicle panel. The unit, which was developed in Australia and is manufactured in Queensland, provides engine governing, auto-synchronising, load sharing and electrical monitoring and control functions within a single micro processor-based module. The governor actuator is of the elec tric stepper-motor type. The H einzmann unit is responsible for the automatic starting sequ ence, speed ramp-up , a warmup cycle, synchronising, control of power output, a stopping sequence including a cool-down period, and protective shutdown functions.

An Allen Bradley programmable controller (PLC) interprets signals from the Heinzmann unit and is also responsible for monitoring voltages, frequency, battery charger opera tion, lubricating oil pressure and level, cooling water tempera ture and level radiation air flo w, gas purge fa n operation, gas detector signals, alternator temperature, circuit breaker trips and general engine operational fa ults.

Gas Supply Conditions

Scrubbing Towers

Gas is dra wn from under the fl oating cover at 0-10 mm water gauge and delivered to the scrubbing towers by means of one of t\vo centrifugal gas blowers. T he variable speed drives of each of the blowers are automatically controlled by the power plant PLC to keep constant gas pressure at the discharge of the sc rubbing towers (setpoint approximately 4 kPa) w hen engmes are runnmg.

T he biogas contains approximately 4000 ppm v/v of hydrogen sulphide, a level w hich wo uld have significant corrosion impact on the engine internals, and is prescrubbed to much less than the specifi ed 1000 ppm v/v.

T he scrubbers do not use the usual recirculated chemicals but a high-flow, once-through sys tem using partially trea ted efflu ent from Pond 2, the discharged effiuent being returned to the aerated section of Pond 1. Each scrubbin g tower shell is approximately 6 m high and 3 min diameter with a 3 m deep packing of tellerettes . The effiuent supply pump operates continuously and the return pump is controlled by four ultrasonic level switches mounted at different levels within the tower sumps. A combined pressure/vacuum breaker is mounted on top of each scrubber tower above t~e spray header level, to prevent over-pressurisation or implosion.

Gas Engines T he Wauke sha VGF P48GLD engines are a 16 cylinder, 4-cycle, lean combu stion, V-configuration design with a 11: 1 compression ratio . T he engine has a total cylinder displacement of 4 7. 9 litres and is designed to burn a lean air/fuel mixture for low fuel consumption and reduced emissions.

T he selectio n of these particular gas engines was not only based o n unit price in compari so n to equivalent engine units, but the mechanical efficiency and low fuel consumption and, most importantly, the low fu el inlet gas pressure requirement which allows use of gas blowers and avoids the

Gas Heaters As the gas leaving the scrubbers is saturated with water vapour, it is heated by approximately 20°C before it enters

WASTEWATER the engine to minimise engine corrosion, using tvvo-stage flameproof240 V AC electric heaters with encapsulated ele m ents.

Gas and Effluent Pipework Gas pipework is a combination of High D ensity Polyethylene (HDPE) below-ground and 316 stainless steel above-ground. Efflu ent pip ewo rk is HDPE undergound , and hot-dipped galvanised steel above-gro und .

Waste Gas Burner A waste gas burner with capacity of 150 to 600 1113/ hr is available to burn surplus biogas w hen one of the two generating sets is unavailable and during ·w eekend off-peak periods.

Generators The 1500 rpm 900 kVA 415 V genera tors are of the single bearing type.

Each is fitted with anti-condensation heaters, winding temperature detec tors, protection current transformers and an automatic voltage regulator. Waveform distortion is less than 1% phase-toneutral. The solid state automatic voltage regulator (AVR) is powered by a permanent magnet generator so that fault current can be maintained sufficiently long for clearance.

The AVRs are equipp ed with a reactive droop facility for VAR sharing betwee n the two generator se ts.

Because of the fluctuations in the external 22 kV power supply voltage, the AVRs are set for power fa ctor control rather than voltage control.

Protection Of particular interest are the pole slipping protection relays, which are standard GEC Alsthom K Series microprocessor-based directional overcurrent relays configured for phase monitoring.

They protect the generator sets against loss of synchronism in the event of external faults and, in particular, of engine mi sfiring due to gas quality variations. These relays also assist the local distributor, Powercor, by eliminating any possibility of protection trips on adj acent 22 kV feeders in the event of loss of generator synchronism.

The 22 kV external power supply from the Powercor di stribution network is fitted with a single-shot auto-reclosing with a time lag of only three seconds. T ests were carried out to ensure that in the event of mains supply failure both generator sets would safely trip in less than two seconds under normal loading conditions.

Plant Control and Monitoring The generating plant is designed for largely unattended operation from an

operations room_ some five kilometres distant, using a fibre- optic communications link with both manual control and a PLC program under w hich the operator keys in the expected quantity of gas available fo r the day, and the PLC loads the generating sets to use this volume of gas in the most effi cient manner.

A local screen-based operator interface is also provided in the Control Centre and gives the same modes of control. T he generating sets and their auxiliary gas blowers, gas heaters, effluent water pumps and purge systems are automatically sequenced and controlled by an Allen- Bradley PLC 5/ 150 programmable controller, w hich also transmits status and alarm signal facts to the remote operations room.

Safety Features Lagoon gas, w hich contains approxim ately 85 % methane, 1s highly flammable and represents a safety hazard at points ofleakage.

The following measures have been taken to maximise safety in and aro und the gas plant: • m ethane gas detec tion within the generator set enclosures • continuous air purging of generator set enclosures under both running and shutdow n conditions • automatic low-velocity gas purging of the gas pipework prior to generator start up • pipework and scrubber design which inhibits formation of air and gas pockets • m easurem ent of oxygen and m ethan e co ncentration in the gas supply pipework • careful location of potential electrical ignition sources outside the classified hazardous areas w here possible.

Flam eproof or intrin sically safe electrical/instrumentation equipment is used w here this is not possible.

The entire site is fenced off and an inner fence aro und the waste gas burner is provided to protect perso nnel against carry of the exposed gas flame by wind gust.

Environmental Considerations Because of the location of the plant it has been necessary to guard against sulfidisa tion of elec trical condu cting surfaces, corrosion of metal surfaces, wind damage to cubicle doors and door stays under seve re wind conditions, rodent damage to cables and infestation of engine and co n trol cubicles by insects and spiders.

An enclosure 8 m long x 3 m w ide x 3.5 m with acoustic attenuation provided by 100 mm R ockwool has ensured noise levels ofless than 75 dBA at lm distance.

The exhaust gas from each engm e pa sses through a heavy-duty spark-

arresting silencer and is discharged to atmosphere via a 10 m high stack . The stack height and exit velocity were designed to mee t Victorian EPA guidelin es w ith th e aid of Ausplume co mputer software . Low emissio n levels ofNOx (40 gm/tnin) and CO (30 gm/min) are obtained.

Operating Experience Several unique features associated w ith the operation of the generating plant have b een reali sed since the operating period began in February 1996 .

T h e efflu ent qu ality, amount of efflu ent inflow to the lagoo n and ambient temperature have been found to affect methane production within the anaerobic lagoon . Operating experience has shown that methane levels can vary between 70 and 85 % (% v/v) depending on the seasonal and operational conditions.

Variations in methane content vary the fu el energy content, w hich affects full load operation of the gas engines.

At present both a 'winter' and ' summer' gas engine tune has been implemented to alleviate this probl em. Consideration has been given to the installation of an air:fuel ratio controller which senses the outlet oxygen and milintains a constant air: fu el mixture regardless of variations in the fu el energy quality.

Gas scrubbing using effluent water has proven successful over the operating period in maintaining hydrogen sulphide levels well within the required 1000 ppm. An internal inspec ti o n showed a small amount of sludge on the bo ttom of the scrubber and a film deposition of fa tty or oily material on the walls and tell erettes . A washdown with water and detergent has proved suffi cient.

The presence of some water vapour in the gas stream following gas scrubbing and heating has influenced the degree of gas engine spark plug fouling.

The gas engine manufa cturer 1s currently exp erimenting w ith bo th single electrode preciou s m etal and four-electrode standard spark plugs to determine w hich plug type is m ost suitable for this application. T he results of this investigation are still unknown to the authors.

Conclusion Operating experience on thi s novel generating plant is being progressively gathered with a view t6wards larger installations on other lagoons.

The capital cost of the power plant itself was $2.5 M , recovering som e $35 0,000 per ann um of power at current peak pri ces, i.e. a payback period of about seven years.

WATER JULY/ AUGUST 1997

21

WASTEWATER

UNSW : : 1$1,111I~ Ii~~! Iii~ !9:f!~~11p;i!l~l1 );ngineeiing : :

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Postgraduate Coursework Programs Master of Engineering Science , Master of Environmental Engineering Science and GtadDip Specializations include:

• • • •

Environmental Engineering Groundwater Investigations and Management Waste Management Water and Wastewater Treatment

The UNSW School of Civil and Environmental Engineering is one of Au stralia 's most respected providers of postgraduate engineering studies. Our strong links with industry ensure that we provide further education that is relevant and up to date. The external courses, which are available on a fee paying ba sis, can be completed in one year full time or two to three years part time. Subjects ma y also be undertaken individually to meet continuing education needs.

Mid year entry for Session 2, beginning 28 July, is now available. Some subject restrictions apply. For further information and application forms, please contact: Ms Mary O'Connell, External Studies Program, School of Civil and Environmental Engineering, UNSW, Sydney 2052 Ph (02) 9385 5080 Fax: (02) 9385 6139 Email : M.0Conne11@unsw.edu.au The combined gas collection system at 115 E Lagoon and the power generation plant has a beneficial impact on greenhouse gas emi ssions, as the methane is converted to the carbon dioxide thought to have one twentieth of the impact on the ozone layer.

Acknowledgements T he authors thank M elbo urne Water Corporation for their cooperation and supp ort in preparing thi s paper.

The following contractors participated in this proj ect: Gas Drive Systems (Sydney) and Southside Engineering, (Brisba ne)Generating Sets.

Tait E nginee ring Se rvices, M elbourne-mechanical and electrical site services.

ASET Pty Ltd , Benalla-transformers and switchgear.

Authors Greg Nicholas graduated BE (H ons) in electrical engineering from th e Un i versi ty of T asm ania and is currently Executive Engin eer i,vith the M elbourne Oilice of Sin clair Knight M erz.

Paul Harris graduated BE(Hons) in engw eenng from m echanical Swinburn e In stitute of Technology and is currently a Senior Engineer in the same oilice.

22

WATER JULY/ AUGUST 1997

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Abstract Sea salt brine, or 'bitterns,' a byproduct of salt (NaCl) production from sea water, is a rich source of magnesium . Compared with sea water, which contains approximately 1,350 mg/L M g and 10 ,500 mg/L Na, the brine is relatively free of so dium and may contain more than 90,000 mg/L M g.

The lime/sea water process is an establi sh ed technology in Scandinavian countries and is highly effective for removing phosphorus, turbidity, colour and pathogens. Compared with sea water, the main advantages of using sea salt brine as a source of M g include reduced effiuent volume and salini ty and the need for a smaller chemical feed sys tem. The reduce d so dium and chloride concentrations also provide a scope for inland application s and effiuent reuse for irrigation and industrial purpo ses.

Optimisa tion of co ntaminant removals requires precipitation of a minimum quantity of M g, in this case 24 mg/L. Numerous combinations of lime and salt brine dosages can be used to precipitate the desired quantity of Mg. The selc:;ction of chemicals do se combination for treatment mu st be optimised through careful examination of the quantity and characteristics of the sludge produced, the final salinity of the effiuent , and the costs associated with the various do se combinations.

Key Words Lime treatment, sea water, sea salt brine, magnesium, wastewater treatment, disinfection , coagulation, flo cculation, treatment optimisation

Introduction Where the main objectives are to control phosphorus, colour, turbidity

and pathogens and produce an effiuent suitable for irrigation or manne discharge, physicochemicaJ treatment is co nsidered to be an appropriate was tewater treatment technology for smaller co mmunities (Taylor et al. , 1994; Gambrill et al. , 1992; Ferguson and Vrale, 198 4; Odegaa rd , 1989).

Physico chemical treatment is also widely used in industrial wastewater pre-treatment and secondary treatment applications. Chemical addition, mostly using polymers and aluminium and iron salts, is u sed in conjunction with biological treatment by a few plants in Australia to remove pho sphorus and enhance sedimentation (Davis, 1993).

Lime use has been limited to a few applications, including the advanced treatment facility in Canberra at the Lower Molonglo W ater Control Centre, the municipal treatment plant at Kambalda, W estern Australia and the Central Zone Treatment Plant in Darwin (Burgess and Simpson, 1993) .

Thi s paper describ es the performance, application and optimisation of the lime/sea salt brine process and compares the use of salt brine and sea water as sources of M g for coagulation.

This treatment process, with further development, has considerable potential to reduc e the discharge of residual organic matter and nutrients and disinfect the final effiu ent before discharge.

Coagulatlon/Flocculation with Lime and Magnesium. Lime is

commonly used in water and wastewater trea tment to achieve softening, clarifi cation , precipitation of phosphorus , disinfec tion , and removal of colour, heavy metals and other trace contaminants. Lime reacts with the alkalinity in water and precipitates as calcium carbonate (CaCO 3). Above a pH of8 to 9, calcium carbonate particles carry a negative charge (Ayoub, 1994) which

does not promote interac tion with the negatively charged colloidal particles in solution. The negative charge limits the lime treatment's ability to effectively remove turbidity and contaminants such as residual pathogen s and pho sphorus-containing particles.

M agnesium hydroxide, M g(OH) 2 , is an effective coagulant (Leentvaar and R ebhun, 1982). Below a pH of approximately 12 , the positively charged magnesium hydro xide particles promote interaction with the negatively charged colloidal particles in solution.

The favourable electrostatic interaction destabilises col1oids, promotes flo cculation and improves settling (Leentvaar and Rebhum, 1982). M agn esium sources include magnesium deposits and sea water.

Lime/Sea Water Treatme!'lt Process. Reporting on the Norwegian

experi ence, Odegaard (1989) concluded that th e lime/sea water process is a suitable, low-cost technology for coas tal communities and summarised the performan ce of 56 plants in Norway treating wastewaters generated by equivalent populations of 2000-75 0,000. The plants located near the sea use<;:! the lime/sea water treatment proc ess. Such plants typically achieved the following contaminants removal results: 84-90% TSS; 81-85% BOD 5 ; 71-82% COD; 90-93% total P; and less than 1000 coliform count per 100 mL. The sludge is used on corn production areas after storage for few months in Norway (Odegaard, 1989) Based on full- scale application in Norway, the typi cal process wo uld consist of screening, grit' removal, sea water and lime addition systems, rapid mixing, flocculation , sedimentation and a system for sludge recycling (Figure 1).

Lime/Sea Salt Brine Treatment Process. Sea salt brine is a by-product

WATER JULY/A UGUST 1997

23

WASTEWATER of salt produ ction from sea water.

Evaporation of sea water results i11 th e crystallisation of sodium chloride and the concentration of magnesium in the brine. The sea salt brine supplied by Cheetham Salt Limited (Australi a) contained approximately 91,800 mg/L M g. Compared with sea water, the brine is relatively free of sodium and contains a reduced level of chloride. If diluted to a M g concentration of 1,350 mg/L, which is equivalent to the M g concentration in sea water (Table 1), the brine would contain less than 90 mg/L Na and 3,500 mg/L Cl compared with 10,500 mg/L Na and 19,000 mg/L Cl in sea water. Accordingly, as a source of Mg, the brine results in a significantly smaller increase in efflu ent salinity and an insignifi ca nt increase in sodium (Na+) co ncentration. In the experiments reported in this paper for exampl e, the addition oflime (pH = 11) and 48 mg/L M g from sea water to the wastewater increased the condu ctivi ty and TDS respectively from 1.36 mS/cm and 1,070 mg/L to 3.61 mS/cm and 2,960 mg/L. The additio n ofLime (pH = 11) and 48 mg/L M g from sea salt brine increased the conductivity to 1. 63 and the TDS to 1,290 mg/L.

Experimental Evaluation Jar test experiments were condu cted to evaluate the enhancing effec ts of the sea salt brine addition on lime treatm ent . To facilitate sludge volume measurem ent, one litre Imhoff cones were used in stea d of th e standard beakers. During each experimental run , the same solar brine dose was added to each of the six co nes before the addition of lime. Lime was then added at increasing quantities to the co nes.

Following lime addition, the wastewater was mixed for one minute at 150 rpm then slowly mixed at 25 rpm for 15 minutes to achieve flo cculation. After 30 minutes of settling following flo cculation, the sludge volume was measured and a portion of the supernatant was siphoned out for water quality analysis.

The experimental development was carried out on screened and degritted wastewater obtained from Fairfi eld wastewater trea tment plant located in

I

:ume

Sea Water

----- .

Figure 1 Lime/sea water chem ical treatment plant (Odegaa rd , 1989) (A=Grit Removal ; B=Rapid Mixing; C=Floccu lation ; D=Sedimentation; E=Sludge Recycling) 1ooo r---c--::----,-,.,-----,-.,------,---

-+-

E.\1cma.l MJ• l60mg/L

-

30 , - - - - - - - - , - - - - ~

~

- 0 - £.\1cmal Mg•IIO mJfl.

900

---

":

fa1cnu1 Mg•48mg/L

800

8

100

e 600

P. .500 'ii,

--0- fatcmal Mg• 2~ mg/L

-r-

E~tcmal l\·11., 0 mg/L

...•....

Ksa(MJIIOH]I0HJ

§ 400

r

300 200 100

Sea Water (mg/L)

Mg2+ Ca 2+ Na+ K+ S042c 1-

1,350 400 10,500 380 2,760 19,000

* Obta ined from 24

7.5

8.0

8.5

9.0

9.5

100

10.S

11.0

11 5

12 .0

pH

100

200

300

400

500

600

Precipitated Mg (mg/L .as CaC0 3)

Figure 2 Precipitation of magnesium hydroxide

Figure 3 Effect of Mg precipitation on turbidity remova l

Brisbane. The plant trea ts wastewater mainly from dome sti c so urces . All analytical procedures were conducted using standard methods (APHA , 1992).

Turbidity Removal.

Effective turbidity removal results in the removal of pathogens and o ther colloidal particles containing phosphorus, nitrogen and organic contamiriants. The effectiveness of the lime/sea salt brine pro cess in removing turbidity was demonstrated by the experimental results presented in Figure 3. The residual turbidity was reduced to as low as 2-6 NTU , and turbidity removal exceeded 85% as a result of M g precipitation above pH = 10.5 .

The precipitation of m agnesium hydroxide is the key to effective turbidity removal. T he data indicate that a minimum quantity of Mg precipitate of approximately 100 mg/L (as CaC0 3) (i.e. 24 mg/L as M g) was needed to reduce the turbidity to below 6 NTU .

The results also indica te that precipitating additional quantities of magnesium above 100 mg/L (as CaC0 3) did not significantly improve turbidity removal.

The turbidity removal results using either sea water or brine were approximately identical.

Phosphorus Removal. Precipitation of soluble phosphorus is essential for effective phosphorus removal. The results confirmed that soluble phosphoru s (P0 4 -P) was removed by lime precipitation to a negligible value when the pH was maintain ed above approximately 9 .3. Also, the precipitation of M g did not directly contribute to the removal of soluble phosphoru s. The removal of soluble phosphorus alone did not explain th e total phosphorus removal results. The precipitation of magnesium and th e resulting removal

Results and Discussion Coagulation using m agnesium requires precipitation of magnesium hydroxide, Mg(OH)?, and the pH must be raised above approximately 10.2 to 10.5. The solubility of Mg declines dramatically between pH = 10.5 and 11.3 and becom es virtually negligible above pH = 11.3 . The solubili ty of M g(O H) 2 can be described by the solubility produ ct, K, = 10- 9 -4 = [Mg][OH]2, and the data in Figure 2.

The quantity of M g(OH) 2 precipitate can be increased by increasing the pH above 10.2 and increasing the quantity of external magnesium dose. The data in Figure 2 indi cate that precipitation started earlier w hen the external M g dose increased. U sing a relatively large magnesium dose ca n reduce the pH and hence the lime dose req uired to precipitate a certain quantity of magnesium.

Solar Salt Brine* (mg/L)

91,800 30 6,100 19,200 76,000 239,000

'Diluted' Solar Sa lt Brine (mg/L)

1,350 1 90 280 1,120 3,520

Centra l Queensland Sa lt, a division of Cheetham Sa lt Limited.

WATER JULY/ AUGUST 1997

.,

o+--,~~-~--~-.,.-ll'l>l----1

Table 1. Minera l Composition of Sea Water and Sea Sa lt Brine

Parameter

Effluent

D

WASTEWATER ,oo~-- - - - - - - - 8.0

~

160

E

i

• Mgppt ==80mg,'LasCaCOJ 0 Mgppt ,. IOO~uCaCOJ

"'

7.0

ig

6.0

4.0

~

...

) .0

I<'

2.0

~

LO

O

0

SeaWIUer

•

SeaWaterBriJ'le

80

ii

8 70

C Sea Water

•

Mgppt=l25m&fLasCaC03

• ScaWakS Brine

0

Mgppt o: ISO~asC1COJ

6

so

"8 60 ll• "

8

·~· •s;, o•

0

100

O<D 0

30

o

200

• oo

I

300

'!,

• 400

500

600

20

Dr,

ao •

40

•

o~

0.0

,o

0

0

•a. •o •c

• +--~-o....co•...-u.....•_•_oo_.,._•___.......,..•o 0

Precipitated Mg (mg/Las CaC03)

100

200

300

400

500

40 20

600

+--~-~_.;,;.....,-,-,._..--;:.........--"I

280

300

320

Precipitaled Mg (mg/L as CaCOJ)

Figure 4 Effect of Mg precipitation on tota l phosphorus remova l

Figure 5 Effect of Mg precipitation on colour remova l

340

2000

---- E.utnalM,•4Slfl/L ---0- EumalM,•ll•

1800

O Mgppt = IOOmaJLasCaCOJ o Mg ppt "' 12s mg/L as eacOJ •

300

325

350

375

440

460

0 M1ppt • IOOmi,'LuC.COJ

i,,,,

• Mgppt• 150111J/L111C.COJ

600

1400

1200 JOOO

Mg ppt:J50mg/LasCaC03

s,o -<=--';....---~------------< 275

0.8 0,6

420

O M1pPt• ll.Smg1LuC.COJ

~

Mgppt .. 80mg/LasCaC03

400

a Mgppt• 80ingll.uC.COJ

_,._ Earm•B\i •O-.t

•

380

Figure 6 Lime and Mg req uirements to precipitate specific quantities of Mg

, r Elltl!IIIM1•2Aq,t

........... Euena!MJ•lfOqot

360

Lime Dose (mg/L)

400

425

4SO

475

Li me Dose (mg/L)

0.4 +--"'""T""...--,----.-,--~----.---1 0 JOO JOO JOO 400 lOO 600 JOO Precipimted Mg (mg/!. as CaCOJ)

soo +-------------,....--l m

300

325

350

375

400

41S

450

475

Lime Dose (mg/L)

Figure 7 Sludge production assoc iated with precipitating specific quantities of Mg

Figure 8 Effect of Mg precipitation on sludge solids concentration

Figure 9 Efflu ent sa li nity associated with precipitating specific qua nt it ies of Mg

of parti culate and co lloidal matter containing phosphoru s, including the precipitated pho spho ru s particles, enhan ced to tal pho sphoru s rem oval (Figure 4) . The data indi ca te that fo ll owing the turbidity reduction results, a minimum quantity of M g precipitate of approxima tely 100 mg/L (as CaC0 3) was needed to reduce total phosphorus to below 1.0 mg/L. Similar to turbidity rem oval, the total phosphorus rem oval results using sea water or the brine were nearly identical with sea water showing slightly better results.

Colour Removal. Lime treatment combined with magnesium hydroxide precipitation from either sea water or sea salt brine sources, resulted in significant colour removal (Figure 5). Colour was m easured using filtered samples after pH adjustment to near neutrality.

Colour removal can be attributed to chemi cal reactions, coagulation and adsorption onto precipitating particles, in addition to po ssible precipitation of trace colour contaminants. The data indicate that colour removal increased as magnesium precipitation increased reaching a residual colour of approximately 20-30 PtCo units. A minimum M g precipitate quantity of approximately 100 mg/L (as CaC0 3) was needed to reduce colour to below 30-40 PtCo units.

M g precipitate of approximately 100 mg/L (as CaC0 3) (i.e. 24 mg/L Mg) was needed to produce the optimum trea tment results. In additio n , th e precipitation of additional quantities of M g above 100 mg/L (as CaC0 3) did not significa ntly enhance the treatment efficiency but resulted in extra sludge production .

N umerous combinations oflime and salt brine dosages can be used to precipitate the minimum quanti ty of M g precipitate as presented in Figure 6.

T he data show an inverse relationship between the lime dose and the brine dose. For example, to precipitate 125 mg/L M g (as CaC0 3) approximately 425 mg/L lime dose was needed w hen the external M g dose was 24 mg/L. The required lime dose was approximately 335 mg/L w hen the external M g dose was 160 mg/L. The decision to u se a high lime dose combined with a low Mg dose or a low lime dose combined with a high M g dose must be made after careful examination of the quantity and characteristics of the sludge produced, the final salinity of the effluent and the relative cost of the chemicals. The quantity of sludge resulting from precipitating a certain quantity of m agnesium is direc tly related to the quantity of CaC0 3 precipitate (Figure 7).

Accordingly, minimisation of sludge production requires a high external magnesium dose combined with a low lime dose.

Minimisation of M g(O H )2 precipitati on is also essential for enhancing the settling and thickening characteristics of the sludge. This is becau se magne-

sium hydroxide particles are gelatinous in nature and occupy a large volume compared with calcium carbonate particles. T he data in Figure 8 show the negative impac t of increased M g precipitation on the thickening quality of the sludge as measured by the sludge solids concentration . T he concentratio n of sludge solids increased as M g precipitatio n decreased. Also, for a given quantity of M g precipitate, the concentration of sludge solids increased as the quantity of external magnesium dec reas ed du e to increased lime demand. Accordingly, optimisation of the sludge se ttling and thickening characteristics requires the use of a combination of a high lim e dose and a low M g dose.

Increasing the salt brine dose increases effluent salinity (Figure 9).

The efflu ent salinity is not of maj or conce rn w hen efflu ents are direc tly discharged to marine waters. However, w h en efflu ents are considered for inland applica tions and irriga tion , minimi sation of efflu ent salini ty becomes a!1 important treatment obj ective . Minimisation of efflu ent salinity whil e precipitating the mimmum quantity of M g(O H ) 2 requires a low M g (brine) dose combined with a high lime dose.

Sludge recycling in continuous flow treatment systems su ch ' as the on e described in Figure 1 also contribute to enhancing the systems performance .

Odegaard (1989) and Ferguson and Vrale (1984) reported that recycling results in the fo llowing advantages: enhancement of steady- state operation;

Optimisation of Chemicals Use Limiting M g precipitation to the minimum quantity required to achieve the desired treatment efficiency is the key to optimising the performance of the process. In this case, a minimum

WATER JULY/ AUGUST 1997

25

WASTEWATER reduction in chemi cal requirem ents; protection against transient failure of chemical feed system s; reduction in sludge production; and improvement of treatment efficiency.

Conclusions Precipitati on of M g significantly improves the perfo rmance oflime treatment. The process achieved the foll owing removal results: 76% BODS, 71% COD , >99 .9% Faecal Coliform, 90% turbidity, 96% total phosphorus, 98% soluble phosphorus, 96% TSS , 8S% filtered colour and 43% TKN. The high removal of pathogens eliminates the need for effluent disinfection. The process results in a chemically stable .and easy-to-dewater sludge with high nitroge n , phosphoru s and organic content. The maj or limitations of the process include: high sludge production; high residual pH; and incomplete BODS and TKN removals.

Optimisation of the performance of the process requires precipitation of a mm1mum quantity of M g( OH)2 .

Numerous combinations of lime and salt brine dosages can be used to precipitate the desired qu antity of M g.

H owever, the decision to use a certain lime and Mg dose combination must be optimised after careful examination of the quantity and characteristics of the

26

WATER JULY/ AUGUST 1997

sludge produced, the final salinity of the effluent, and the¡ costs associated with the various dose combinations.

Acknowledgements Thi s study was supported by a research grant from the Queensland Foundation for Local Government E ngineering. Special thanks to R ay M oore, Secretary of the Foundation , an d C hris Lan e, Proj ec t Liaiso n Officer, fo r facilitating the study.

References APHA (1992) Standard M ethods for the Examination of Water and Wastewater.

Publisher: American Public H ealth A ssoc. 18th Edi tion, Washington D C. Ayo ub , G. (1994) T he Lime- Seawater Process.

ASCE-SAS Regional Confere nce, Oc t. 19- 23, M anama, Bahrain, p. 495-504.

Bayley, R , and Cooper P (198 1) Physicochemical Treatment: An Appraisal.

Notes on Water R esearch , Issue No. 26, Feb., 1981, ISSN: 0307-6652 , Published

by T he Water R esearch Centre, UK. .

Burgess, M . and J. Simpson (1993) The Potential fo r a Low Technology, High Perfo rmance Was tewater Treatment Plant fo r Smaller Coastal Communi ties .

15th AWWA Federal Conference, Gold Coast, Qld, April, p. 15 1- 156.

Davis, C (1993) W astewater T reatment in Australia. W aste M anagem ent & Environmen t, 4, Sept. 1993 , p. 27-37 .

Ferguson , J .F. and L. Vrale (1984) Chemical

Aspects of the Lime Seawater Process. ].

W ater Poll. Control Fed. , 56, No. 4, p.

355-363.

Gambrill, M .P ., D .D . Mara, and S.A. Silva (1992) Physicochemi cal Treatment of T ropical W astewaters . W ater Sci. & T echn. , 26, No . 7-8, pp. 1449-1458 .

H augan , B.E. (1977) Effect of Magnesium or Polyelectrolytes as Coagulant Aids with C hemical Precipitati on with Lime.

N orwegian Ins titute fo r W ater R esearch (in Ferguson and Vrale, 1984).

Leencvaar, J. and M . R ebhun (1982) Effect of Magnesium and Calcium Precipitation on Coagulation Floeculation wi th Lime.

W ater R esearch, 16, p. 65 5-662.

O degaard, H. (1989) App ro priate T echnology for W astewater Treatment in Coastal T ourist Areas. W ater Sci. & T echn. , 21, No. 1, pp. 1-17.

Taylor, H.D ., M .P. Gambrill, D .D. Mara, and S.A. Silva (1994) Upgrading a LowCost Physicochemical Wastewater Treatment Plant to Solve O perational Problems. W ater Sci. & Techn. , 29, No. 12, p. 247-254.

Author Dr Abdallah Shanableh is a Senior Lecturer in Environmental Engineering at th e Qu een sland University of T echn ology, GPO B ox 2434, Brisbane Qld 4001. H e has been an A ssistant Professor at the University of Jordan , and a Senior En vironmental Engineer with Parsons Engin eering Scien ce, USA.

WASTEWATER

Gorillas like wa ter. Being an engineer, I didn 't profess to know this fact until I went on AWW A's dusk tour of Taronga Park Zoo' s wastewater treatment plant on 26 March this year.

It was a balmy autumn evening and the tour, led by the Zoo's Operations Manager J an D ekker , included an impromptu visit to the gorillas to see their enclosure and a moat w hich is filled with 650 000 L of recycled wa ter from the plant and changed every two months.

At the time of our visit the exhibit was devoid of vegetation. Apparently the gorillas like to chow down on young shoots and saplings. This has forced the Zoo to provide so me protection for the trees in the 'gorilla forest' until they reach maturity. But the waterfall and moat filled with recycled water were there-sparkling, cascading

over rocks, gli stening in the fading sunJight.

Apparently the moat was installed to discourage the gorillas from crossing over to m eet their spectators. The fact that it was filled with recycled water would have been enough to discourage those species slightly higher in the evolutionary chain , but the go rillas probably weren't told that it was recycled water. And shock, horror, apparently a few of th e adventurous ones used to have a grea t time wading through the moat and they attempted to climb the low balustrade to get onto closer speaking terms with the viewers.

So as well as the moat there is a low voltage electric wire to discourage cross-species communication , and the gorillas merely dip their hands into the moat to pluck out the occasional dropped shallot or apple before eating it.

WATER JULY/ AUGUST 1997

27

WASTEWATER Zoo's Wastewater Treatment Plant The wastewater trea tment plant provides 250 000 L of recycled water a day which the Zoo uses for ornamental moats, hosing down animal enclosures, toilet flu shing and lawn irrigation. The quality of the recycled water produced-with zero total coliforms and viru s indica tors-is of a much higher standard than that required by current NSW R ecycled Water Guidelines.

Although the irrigation system has yet to be commissioned, the Zoo still requires an enormous volume of wa ter.

Whilst the water in the gorilla moat is changed every two months, there are p1any other uses for the water w hich are required on a much more frequent basis. For example, a new tapir exhibit which also uses recycled water requires about 65 000 L and has to be changed every two days.

Plant's History The development of was tewa ter treatment at Taronga Zoo has a very interesting hi story. A treatment plant was first installed in 197 4. T his was based on the Pasveer Ditch intermittent extended aeration treatment and was designed by Public Works.

In 1992, the Z oo received considerable adverse publicity about raw sewage purportedly entering the harbour. In fact the Zoo did have several discharges to the harbour, but none of th em

involved raw sewage. Discharges included the effluent from the treatment plant (which did not provide a good quality effluent due to overloading), the seal tank water changeover, and stormwater runoff It was acknowledged that improvements were needed and the decision was made to upgrade the treatment plant.

Coinciding with this was the issue of water supply. The Zoo was then purchasing 400 m 3 of wa ter a day from Sydney Water-a not insignificant opera ting cost.

T he opportunity was taken to develop a water supply and wastewater strategy in a combined solution. The plant now supplies a significant portion of the water needed by the Zoo and has reduced operating costs.

Environmental Cleanup The Clean Up Australia group led by Ian Kiernan coordinated a series of private companies and publi c autho rities to develop a new treatment and recycled water sys tem. In the first co nstruction phase Sydney Water installed the ring main w ith pipes supplied by Jam es H ardie. During the construction of the wastewater treatm ent plant itself ANI Kruger, MEMTEC , Public Works, Sydney Water and others provided time rather than money. Stormwater was also catered for by installing the ring main, and a first flu sh tank (500 m 3) was built next to the wastewater treatment plant.

Provision was made for overflow from the plant to be discharged to the harbour at Whiting Beach.

Technical Aspects The wastewater treatm ent plant , w hich was commissioned in November 1996 at a cost of abo ut $2 .2 million, involves: • manual screening • vortex grit arrangement • biological reactor (co ntinuo us), which is the converted Pasveer ditch, with separate clarification • a balance tank followed by MEMTEC microfiltratio n unit • UV di sinfection • a 500 m 3 storage tank that allows transfer of disinfected effluent to the nng mam • a gravitational UV system to cater for high flows above the recycled water demand and allow discharge to the harbo ur.

Treatment plants no t only produce effluent but they also generate solids byproducts such as sludge from the biological system, grit and screenings such as rags, paper etc. removed by the screens. The zoo boasts a unique solids co mpo sting/pit arra ngement w here waste treatment plant solids are mixed with straw and other waste products from the enclosures. 'This is used for landscaping aro und the Zoo and , to complete the cycle, possibly even for mulching the degraded vegetation in the gorilla enclosure!

The 21st World Water Congress and Exhibition Madrid • Spain • 20th - 26th September 1997 • Join the world's foremost gathering of water industry experts in the exciting city of Madrid • Leading scientists, engineers and managers from around the world will be attending the 21st World Water Congress • The Congress and accompanying exhibition will be held in the Palacio Municipal de Congresos de Madrid • It features a wide technical programme and full social programme • For full detai ls contact: International Water Supply Association, l Queen Anne's Gate, London SWl H 9BT. Telephone: +44 171 957 4567. Facsimile: +44 171 222 7243.

IWSA E-mail IWSA@dial.pipex.com

Q) AIDE 28

Asociaci6n Espanola de Abastecimiento de Agua y Saneamiento (AEAS), C. Orense, 4-1° dcha.A, 28020 Madrid, Spain.

Telephone: +34 l 556 4300 Facsimile: +34 l 556 8998

WATER JULY/ AUGUST 1997

AIDE

ENVIRONMENT

VICTORIA'S

GROUNDWATER PROTECTION POLICY D Strudwick Abstract The State Environment Protec tion Policy (Groundwaters of Victoria) is currently being finalis ed by the ¡ Victorian Environment Protection Authority (EPA). Following the release of a draft policy in October 1994, 70 public submissions were received, many of which provided lengthy and detailed comments. This paper discusses the need for a policy, its basic co mponents, aspects of the extensive public consultation process and the key policy issues including attenuation and polluted gro undwater zo nes, the cleanup of polluted groundwater, total containment and risk assessment.

Key Words Groundwater, State environment protection policy (SEPP) , discharge, pollution, attenuation zone, beneficial use

Introduction In October 1994 the Victorian EPA released a draft State Environment Protection Poli cy (Gro undwaters of Victoria) for public comment. Seventy formal submissions were received.

A groundwater policy is required due to the considerable contribution of groundwater as a resource and in the environment. A number of activities have either polluted or have the potential to pollute groundwater, and there is no single, consis tent legislative approach to groundwater protection in Victoria.

The EPA is currently finalising the policy for recommendation to the Governor-in- Council. Thi s paper discusses the policy, its background and the key issues and implications of the policy as it is currently proposed.

Groundwater as a Resource Beca use groundwater suppli es approximately 10% of Victoria's total water consumption it is a significant existing reso urce (Department of W ater R esources Victoria , 1989). The divertible volume of groundwater in Victoria is estimated to range from 900 000 to 1 400 000 ML per year, of which approximately half is 'fresh' (TDS<1500 mg/L), one third is of marginal quality (TDS 1500-5000 mg/L) , and the remainder is of poor quality (D epartment of Water R esources Victoria , 1989).

At least 60 Victorian townships are wholly or partly dependent on groundwater for their domestic water supply (Scott and C hristoff, 19 91). These include Sale, Portland , Port Fairy, M yrtleford , N hill , Kaniva, H eywood and Geelong. While som e such as Nhill rely totally on groundwater, others such as Geelong use groundwater as a drought relief supply. In the 1982-3 drought, Geelong derived 50% of its water from the Barwon Downs bore fi eld (Scott and Christoff, 1991).

Numerous individual rural residen ces also rely on groundwater for household supply.

The bottling of 'still' (spring) water is a fast-growing industry in Victoria.

The bottled water industry estimates that exports of Victorian bottled spring water generate approximately $12.4 m per year and that Victoria produces more than 50% of Australia's bottled spring water. C urrent commercial sources of spring water are located near Ballarat, M acedon Ranges, Yarra Glen, Dandenong R anges, Bright and Traralgon.

Mineral water resources are located in the Victorian Central Highlands

(Daylesford-Hepburn Springs, Vaughan Springs etc.) and near Kyneton , Yea and Donnybrook. Mineral water for commercial bottling has the highest economic value of all groundwater, at point of sale being approximately $1 m per ML. In addition to the value of drinking mineral water, mineral water is co nsidered to be highly valued for bathing. The Daylesfo rd-Hepburn Springs district is a m aj or tourist centre primarily because of mineral springs.

Tourism contributes tens of millions annually to the regional economy (Shire of H epburn pers. comm .) .

T he use of groundwater for irrigation of crops and pastures is a well established practice in m any areas of Victoria. T here are approximately 4000 licences for irrigation purposes with an authorised extraction of approximately 4 70 000 ML for an area of about 92 000 ha (Rural W ater Co rporation of Victoria, 1992). Irriga tion districts that are w holly or partially dependent on groundwater include Koo W ee Rup, W andin Yallock, Campaspe W es t, Moloort , Loddon , Mitchell Rive r (Maffra , Lindenow), Murray Valley (Yarrawonga) and Ondic. T herefore, it can be said that groundwater supports areas of considerable agricultural value.

Groundwater is also used widely for irrigating domestic gardens, parks, golf courses, cemeteries and race courses.

Groundwater provides an important source of water for livestock, particularly in arid areas where it is often the only viable water sourc,e. Stock and domestic bores in Victoria support approximately 1.5 million head of stock (Rural Water Corp. ofVictoria , 1992).

Indu stry is currently not a major user of groundwater in Victoria , but it can be significant on a local scale. Industrial uses include process (washing) waters at WATER JULY/ AUGUST 1997

29

ENVIRONMENT expressions of groundwater w here the land surface falls below the wa tertable.

Gro undwa ter ca n co ntribute up to 100% of the water in wetlands. These fi gures illu strate the potenti al of polluted groundwater to adversely affect surface wa ter ecosystem s and o ther beneficial uses of surface wa ters.

Threats to Groundwater Quality

Groundwater under pressure? High quality water spurts from an artesian bore In the Barwon Downs borefleld.

dairies, abattoirs and market gardens, as well as use in industrial cooling towers (e.g. La Trobe Valley and Anglesea electricity generation plants, Portland aluminium smelter).

Groundwater in the Environment G roundwa ter of varying quality discharges to waterways, wetlands, the marine environment and sometimes to the land surface. The contribution of groundwater di scharge to stream/river flow (basefl ow) and wetl ands vari es enormously, but is often underestimated. H eislers (1 993) refers to studies that attribute 70-80% of to tal annual stream flow in the North Maroondah catchments to baseflo w . A CS IROcommissio ned report states that 88-98% of contaminated groundwater in the basalt aquifers under M elbourne's western suburbs discharges to su rface waters, w hile the remainder discharges to Port Phillip Bay (H ydrotechnology, 1993). C ollette et al. (1995) reported basefl ow contributions of 55- 65% of total annual flow of the Yarra River in mid-catchment areas (Milgrove and W arrandyte). Some wetlands are surface 30

WATER JULY/ AUGUST 1997

M any activities have either polluted or have po tential to pollute groundwater. These include h eavy industry, community was te disposal (landfills, septi c tanks, was tewater irriga ti on), leaking undergro und sto rage ta nk system s and intensive agriculture.

The threat of heavy industry mainly refers to past activities such as bulk chemical storage facilities , fac tories and manufac turing. Industrial waste disposal has no t always met today' s hi gh standards. In the past, industrial waste has been disposed to open holes in the ground or inj ected directly into aquifers via disposal bores. The types of industrial wastes that are known to have polluted groundwater include petrochemicals, nitrating solution , dyes and dairy w hey.

Landfills accept 100% of the community's so lid was te (excluding re u se and recycling) . The Victorian community (including indu stry) pro du ces approximately 4 300 000 tonnes of solid waste each year (i.e. 956 kg/person/y) (EPA , 1997). T here are currently about 60 licensed landfills operating in the M elbourne metropolitan area. Only relatively recently have groundwater protection measures been included in landfill design and operation.

W astewater irrigation and the intensive use of septic tanks are threats to groundw ater quality . High nitrate concentrations occur in groundwater as a result of intensive use of septic tanks at Venus Bay (Hoxley and Dudding, 1994), Benalla (Hoxley and Dudding, 199 4), Loch Spo rt and the lower M orningto n P enins ula (Dro manaPortsea).

Underground tank system s used for storing petroleum products have been known to leak product in to the subsurface. Product floating on the watertable is a source of dissolved phase aliphatic and aromati c hydrocarbon contaminati on . Where underground storage sys tem s are located close to surface waters, pollution of those surface waters can occur.

Intensive agriculture such as feedlo ts, dairies, market gardens and irrigated crops and pastures have the potential to pollute groundwater due to the high production of animal wastes and the use of fe rtilisers and pesticides.

Inadequate Legislation Vari ous provisio ns fo r groundwater pro tection occur in the En vironment Protection A ct 1970 (Vic), W ater Act 1989 (Vic), H ealth (Gen eral 1988 (Vic), A m endm ents) A ct Ca tchm ent and Land Protection A ct 1994 (Vic) and Local Governmen t A ct 1989 (Vic). State environment pro tecti on poli cies developed under the E nvironment Protection Act such as W aters of Victoria, W aters of th e Y arra River and Tributaries, and Th e siting and m anagem ent of landfills receiving municipal wastes also contain provisions fo r the pro tection of groundwater.

This existing fram ework of legislation and State enviro nment protec tion policies (SEPPs) is widely considered to be con fus ing and inadequate fo r protecting the groundwater enviro nm ent . The propo sed groundwa ter poli cy offers a single, co nsistent approach to groundwater pro tec tion.

Public Consultation on the Draft T he draft poli cy and associated policy impact assessment (PIA) were released fo r public comment in O ctober 1994. Approximately 1700 copies were distributed. During the foll owing six months, 70 formal ,submissions were received from a wide range of interested parties including indu stry group s, groundwater users, water authorities, environment groups, groundwater con sultants, local government and government departments. Some of the submissions were longer than the policy itself.

As a result of some of the responses and the extent of interest in the draft policy, the E PA undertook furth er public consultation with groups including the Statewide Groundwater Advisory C ommittee, Altona C hemical Complex E nvironmental Steering C ommittee, the Victorian Planning and E nvironmental Law Association , the Internation al Associatio n of H yd rogeologists, the Au stralian C hamber of M anufac tures and the rural water, landfill , bottled water and La T rob e Valley electri city generation industries.

T he final policy will be a res ult of formal submissions and the subsequent consultation .

Components and Goal of the Policy (

As w ith any SEPP , the proposed Victorian policy consists of a policy goal as well as the basic components of identifying segments, benefi cial u ses and obj ec tives. It also outlines a program to assist in the attainment of the policy obj ectives.

ENVIRONMENT The goal of the propo sed policy is to ' maintain and improve groundwater quality sufficient to protect existing and potential beneficial uses of groundwaters throughout Victoria .'

Segments of the Groundwater Environment Segments of the groundwater environment have been determined according to the water quality indicator, total dissolved solids (TDS). TDS was chosen as the most appropri ate indicator to define segments as it is commonly and easily measured and is the mo st common determinant of groundwater use. Five segments have been determined and are shown in .Table 1.

Table 1 Segments of the ground water environment Segment

Al A2 B C D

TDS ran ge {mg/ L) 0 - 500 501-1000 1001-3 500 350 1- 13,000 greater than13,000

T he segm ent boundaries are generally those for TOS in the Australian Water Quality Guidelin es for Fresh and Marin e W aters (ANZECC, 1992). For exa mple, the upp er boundary for segment B is 3500mg/L TDS. This is the upp er limit for TDS in water suitable for irrigation (of salt-tolerant species 111 well drained soils) (ANZECC, 1992).

T he natural spatial variation in groundwater quality can result in segm ents being difficult to determine.

T he policy states the EPA shall determine the segment that applies, taking into account as many sources of information as it has reasonably available.

Beneficial Uses The propo sed policy identifies benefi cial uses to be protected within each segm ent (see Table 2). The beneficial uses of groundwater are based on historically accepted uses of groundwater such as potable, irrigation, stock, industry, as well as a recognition of groundwater's inter-relationship with surface water (maintenance of ecosystem s). T he protection of groundwater quality so that buildings and structures in contact with groundwater are not adversely impacted is also included .

Table 2 shows that the number of beneficial uses to be protected decreases as th e TDS of the gro undwater increases. 'M aintenance of ecosystem s,' ' industrial water u se' and 'buildings and structures' are protected in all segm ents.

The EPA may determine that a benefi cial use identified in Table 2 does 32

WATER JULY/ AUGUST 1997

.

Table 2 Protected beneficial uses of the segments Segments (mg/LTDS)

Beneficial Uses

1) Ma intenance of ecosystems 2) Potable water sup ply: desirable acceptable 3) Potable mineral water supply 4) Agricu lture, parks and ga rd ens 5) Stock waterin g 6) Industrial water use 7) Buildings and structures

Al

A2

(0-500)

(501-1,000)

. .

not apply w here: • there is insufficient yield to sustain the beneficial use.

• the background (natural ambient) c nce ntration of a water quality indicator other than TDS may be detrimental to the beneficial use.

• the benefi cial use is imprac ticable due to one or more soil characteristics .

• groundwater is within a polluted groundwa ter zone that has been identifi ed by the Authority.

• groundwater is within an attenuati on zone specified within a works approval , licen ce or notice under the Environment Protection Act. W hen m aking determinations on ' insuffi cient yield' the EPA mu st consider variations in yield thro ughout the aquifer and be satisfi ed that beneficial u ses in surrounding areas are protected. Insufficient yield cannot be used to determine that benefi cial uses do no t apply in frac tured rock or karst limestone aquifers.

Although the ben efi cial uses ' m aintenance of ecosystem s,' and 'buildings and structures' are protected in all segments, a proponent or site owner/occupier may satisfy the EPA that they will not be adversely impacted by an activity. For example, a nearby waterway may be permanently upgradient of the site and therefore w ill not be impacted by any on-site groundwater quality degradatio n. Obviously the benefi cial u se 'po table mineral

. ... .. .

B (100 1- 3500)

C (3,501- 13,000)

D (greater than 13,000)

.

.. .

. .

;,.

.

water' is o nly required to be protected w here mineral water occurs.

Groundwater Quality Objectives The proposed groundwater quali ty objectives that defin e the water's suitability for a benefi cial use are predominantly nationally derived water quality guidelines (see Table 3). T he A ustralian Water Quality Guidelines for Fresh and Marin e Waters (AWQG , ANZECC , 1992), a co mponent of the National W ater Quality Strategy, are the maj or source of obj ectives adopted by the policy.

The obj ectives for the benefi cial u se 'maintenance of ecosystem s' are those co ntained in the EPP (Waters of Victoria) or in SEPPs for specific surface water catchments.

The obj ectives for 'potable mineral water' are in the Australian Foods Standard 08.

An additional water quality obj ective for the protection of potable waters from tainting (including mineral water) is evident in Table 3. T his means that contaminants at concentratio ns below the health-based policy objectives shall not be increased so that the groundwater has an unpleasant taste or odour, therefore affecting the beneficial use of that groundwater.

Where the background concentration of a water quality indicator exceeds the groundwater quality obj ective, the

Table 3 Groundwater qua lity objectives Beneficial Use Maintenance of ecosystems Potable Water-Desirable

Potabl e Water-Acceptable

Potable Minera l Water

Irrigation Stock water Industria l water use Bui ldings and stru ctures

Groundwater Qua lity Objectives SEPP (Waters of Victoria), catc hment specific SEPPs TDS <501mg/L AWQG- Ra w waters Th e constituents of groundwater shall not be affected in a manner or extent that leads to ta inting AWQG-Raw waters Th e constituents of groundwater sha ll not be affected in a manner or extent that leads to tainting Austra lian Food Standard 08 The constituents of ground water sha ll not be affected in a manner or extent that leads to ta inting AWQG-irrigation AWQG- stock AWQG-industry Introduced contaminants shall not ca use grou ndwater to become co rrosive to bui ldings and structures

ENVIRONMENT background concentration becomes the objective. Thi s allows fo r aquifers characterised by naturally high concentrations of some indi ca tors to be protected from degradation and not constitute a breach of the policy.

The policy requires that the groundwater quali ty obj ectives in Table 3 are met except: • where an attenuation zone has been designated in a works approval, licence or notice issued under the Environment Protection Act • within a polluted groundwa ter zone identified by the Authority • w here the background conce ntration of an indica tor exceeds the obj ec tive • withi n a groundwater protection zone.

Attainment Program The attainment program provides general direction on how the groundwater quality objectives of the policy are to be achieved. It outlines the responsibiliti es of individuals an d agencies to protec t groundwater quality and contains mechanisms for th e prevention and control of groundwater pollution .

The maj or components of the proposed attainment program are discussed .

The policy is to apply to all groundwa ter and aq uifers throughout Victoria.

Where the provisions of the groundwater poli cy are in consistent with the provisions of other SEPPs with relation to groundwater, th e provisio ns of the groundwater policy will apply.

Attenuation Zones Attenuati on zo nes are parts of aquifers surrounding a source of migrating contaminants, designated by the EPA in works approval, li cence or notice, where the groundwater quality obj ec tives in the policy are not req uired to be ac hi eved . Within atte nuation zo nes, pollutants are allowed to attenuate in an aquifer. Attenuati on zones are a recognition by the EPA that even when all prac ticable preventative measures are taken, some activi ties will still cau se groundwater pollution.

As attenuation zones result in beneficial uses of gro undwater being sacrificed, their applica tion and extent are severely restricted by the policy. Such zones will only be considered by the EPA for landfill s receiving municipal waste, wastewater irriga tion , as h ponds and evaporation basins that are part of a Government-approved salinity management plan. For these activities, the designation of an attenuatio n zone by the EPA is not an automatic right, as it must be sa tisfied that all prac ticable measures have been taken to prevent groundwater pollution.

Any designated attenuation zone will be the smallest area possible, w ith the 34

WATER JULY/ AUGUST 1997

maximum exten t allowed being the boundaries of the premises to which the works approval, licence or notice relates. This does not mea n that contaminants cannot migrate beyond the attenuation zone, but rather the poli cy requires that sufficient attenuation mu t have occurred so that the groundwater quali ty obj ectives are met at the zone boundaries. This restriction is necessary to ensure that the true costs of these activities are borne by the occupier and ultimately the waste disposer.

Attenuation zones will not be designated: • wi thin a gro undwate r protection zone • w here there is an unacceptable risk of detriment to an existing beneficial use of groundwater • in aq uifers with high permeability or low attenuation properties.

Any designated attenuation zo ne shall includ e gro undwater quality rn.onitoring at the zone boundary and a contingency plan to be implemented if groundwater outside the zone becomes polluted.

Polluted Groundwater The EPA can direc t cleanup of pollution under sec tion 62A of the Enviro nment Protection Act. Under this provision, th e EPA can require cleanup by an occupier of any premises upon or from which pollution has occurred, or any person w ho has caused or permitted pollution to occur. T he introduction of the groundwa ter policy will not change the EPA's ability to require cleanup of polluted groundwater. However, by identifying beneficial uses and groundwater quality objectives, the policy more accurately defines groundwater pollution.

Polluted gro undwa ter zones are areas that the EPA defines as having an existing level of groundwater contamination that precludes one or more beneficial uses that would otherwise apply to that groundwater. These zones will serve as a tool for m anagement of existing groundwa ter pollution w here it is not possible or practicable to clean up. The EPA plans to periodically require the reassessme nt of the practicability of cleaning up groundwater pollution.

The draft poli cy propo sed that a schedule listing pollu ted groundwater zones be attached to the policy. T he req uirem en t for the policy to be amended (including a PIA) and declared by the Governor-in-Council each time a polluted groundwater zon e is proposed is, however, seen as being cumb ersom e and co unter to the effici ent provision of information to the community. Instead, it is now envisaged· that the EPA will provide basic

info rmation to the community such as the extent of the polluted groundwater zone, the ben efi cial uses that are precluded, the contarn.inants involved, the source of the pollution and details of any ongoing management or monitoring of the plume.

T he EPA will also provide this informati on to the relevant Rural W ater Authority (ground wa ter resource manager) to ensure that no licences are issued for precluded beneficial uses in the zone.

NAPLs When located in aquifers, nonaqueous phase liquid s (NAPLs) are uncontrolled sources of groundwater contamination. It is therefore proposed that NAPLs should be removed from aquifers in all circumstances unless the site owner/occupier satisfi es the EPA th at re moval is not practicable (e.g. if the NAPL cannot be located) or there is no unacceptable ri sk po sed to any benefi cial use.

Risk Assessment T he groundwater quality objectives identified in Table 3 that define the suitability of gro undwater to beneficial use (Table 2) will apply in all cases. Risk assessment method9logies that are acceptable to the EPA can be used to derive site- specific groundwater quali ty criteria fo r indicators where there is no groundwater quality objective referred to in the policy, or to provide additional information to assist the EPA in determining the nature and extent of groundwater cleanup required.

Quality vs. Quantity T he SEPP (Gro undwaters of Victoria) concerns the maintenance and improvement of groundwater qu ali ty (as is determined by the provision of the Environment Protec tion Act).

Groundwater reso urce manage m ent , determination of the sustainable yield of aquifers, resource evaluation etc. are the roles of those authorised und er the Water Act. Where current groundwater management regimes are likely to result in a reduction in groundwater quality so th at a ben eficial use is adversely affected , the EPA will work with the gro undwater manager to ensure that future resource management strategies are implem ented to minimise the impact on groundwa ter quality.

Potential Beneficial Uses In any situa tion, the beneficial uses proposed in Table 2 apply, regardless of w hether or no t they are current uses.

'Potential' beneficial uses of an aq uifer are those that are not current (see Table 2). For example, for an aquifer containing groundwater that is predominantly

ENVIRONMENT in segment A2 , gro undwater shall not be contaminated so that the poli cy objectives for potable wa ter supply (desirable and acceptable), irrigation , stockwa ter and industrial water use are exceeded. Thi s applies even though these uses may not be current.

The protection of potential benefi cial uses is seen as necessary due to the opportunistic nature of some groundwater use (e.g .. drought relief) and the technical difficulty and major cos t involved in cl ea ning polluted groundwater (prevention is easier than cure).

Total Containment T he term ' total containment' was u sed in an Appendix to the PIA titled ' Indication of Future Guidelines for Landfills.' It was intended to be interpreted as 'the use of compo site liner system s.' M any formal public responses sugges ted that the term is mislea ding and unrealistic, as all liners leak to som e extent. T he EPA accepts th ese criticisms and no longer refers to total containment.

Current Status and Implementation of the Policy We expec t the proposed policy to be finalised by the EPA in the near future.

The respon se to publi c co mment document will be circulated to those w ho provided formal comments and placed in the EPA library befo re co n sidera tion by the Governor-inCouncil.

Implementation of the final policy is expec ted to involve a program that forma lly incorporates the EPA's obligations such as the consideration of attenuation zones in some works approvals and the responsibilities of 'protection agencies' and groundwa ter users that are specified in the poli cy in to their day-co-day activities.

In a number of circumstances the proposed policy is already being implemented through existing program s and legislation. Exampl es include: (i) the consideration of the proposed beneficial uses and groundwater quality objectives by proponents in assessing potential impacts to groundwater posed by a proposed activity. (ii) the inclu sion of groundwater protec tion m echanisms (eg. landfill leachate collection and trea tment) in works approval applica tio n s and licences . (iii) the use of the proposed groundwater quality objectives to define existing groundwater pollution. (iv) the development of national guidelines on underground petroleum storage tank systems by the EPA and other state environmental agencies in conjunction with industry.

From this it ca.n be said that the EPA and maj or stakeholders have been effectively working with key components of the proposed policy for some time, and that the successful implementation of the final policy is not expected to be difficult to achieve·.

Conclusions The proposed policy offers a single, con sistent statutory approach co gro undwa ter protection in Victoria.

Once declared by the Governor-inCouncil , the policy is expec ted to provid e th e means to maintain and improve groundwater policy, sufficient to protect existing and po tential beneficial uses of gro undwa ter throughout Victoria.

References ANZECC (1992) Australian Water Quality Guidelines for Fresh and Marin e Waters, Australian and New Zealand Environment and Conservation Co uncil, November 1992.

Collette, L., Shu gg, A., and O'Rourke, M. (1995) 'Ecological Impacts of Groundwater Di scharges to Catchment Streams and Port Phillip Bay' (draft), Special Publication, Catchment Strategy Division, M elbo urne Water Corp.

D epartme nt of W ater R eso urces Victoria (1989) Water Victoria: A Water R eso urces Handbook, Victorian Government Printing Office, Victoria.

EPA (1997) The Lan dfi.11 Levy and Solid Waste in Victoria: Some Facts and Enviro nment Protection Figures, Autho rity Publication No . 524, Jan. 1997.

H eislers, D. (1993) Gro undwater in the Highlands, CentraJ Victorian D epartment of Co nservation and Na tu ral R esources, Water Divisio n , Victorian Government Pri nti ng Office, Victoria.

Hoxley, G ., and Dudding, M. (1994) Groundwater Contamin ation by Septic Tank Efflu ent: T wo Case Studies in Victoria, Australia,' Proceedings ofWater Down Under '94, XXV Congress of the of Imernational Association Hydrogeologists, Adelaide, November 1994, Vo lume 1, pp 145-152.

H ydrotechnology P ty Ltd (1993) ' Grou ndwa ter and N utri ent Inputs to Port Phillip Bay,' Technical R eport No .

13, Port Phillip Bay EnvironmentaJ Study, CSIRO, Melbo urn e.

Rural Water Corpora tion ofVictoria (1992) AnnuaJ R eport 1991-2.

Scott, D. , and C hristoff, P. (1991) Agriculture and Victoria's Environment: R eso urce R eport. Office of the Commissioner of the Enviro nment, Melbourne.

Author Darryl Strudwick 1s a H ydrogeologist in th e Environmental Ch emistry Unit of th e Victorian Environment Protection Authority, PO B ox 4395QQ, M elbo'urne Vic 3001.

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35

ENVIRONMENT

CURRENT CLEANUP TECHNOLOGIES AND PRACTICES IN THE UNITED STATES ME Peterson Abstract In the United States it has been recognised that the existing technology base is inadequate to remediate hazardous and radioactive waste sites due to the complexity and broad spectrum of problems . New technologies and enhanced cleanup approaches are b eing develop ed and used to remediate contaminated soils, groundwater, solid waste and structu res.

Today, the most commonly u sed technologies for soils and solid waste include soil vapour extraction , incineration , caps, slurry walls and waste excavation and relocation. H owever, cleanup problems exist for w hi ch technologies have not yet been identified and there are limitations to the application of some technologies . If su ccessfully developed , demonstrated and deployed, emerging technologies will collectively establish a technology portfolio from w hich to select the m ost appropriate technology for remediating specific contaminants under a given set of si te conditions and requirements.

Key Words Established/emerging technologies, barriers, soil vapour extraction, incineration, caps , slurry walls, waste excavation/relocation, soil washing, vitrification , elec trokinetics , plasma, in situ stabilisation, engineered barriers, enhanced barrier materials

Introduction A survey of development act1v1t1es throughout the United States (US) has identified a significan t numb er of emerging technologies fo r remediating contaminated soils and solid waste. The development of new technologies is the result of a recognition that the existing technology base is inadequate to costeffec tively remediate hazardou s and radioac tive was te sites du e to the complexity and broad spec trum of problems. Cleanup problems exist for which technologies have not yet been identified and there are limitations to the application of some technologies.

36

WATER JULY/ AUGUST 1997

The limitations include the effectiveness of the technology at removing contaminants to specified limits, high cost, the lack of technology applicabili ty to the contaminants or site conditions , cleanup times , secondary waste generation and the high worker risks resulting from exposure to contaminants. These types of issues are driving the development of new technologies. If successfully develope d , demonstrated and deployed, the em erging technologies will collectively establish a technology portfolio from w hich we can evaluate and select the most appropriate technology for remediating specific contaminants under a given se t of site conditions and requirements.

This paper provides an overview of the environmental cleanup problems in the US and describes the types of established and em erging technologies that are designed to remediate waste sites.

Established Technologies Today, the most co mmonly used technologies fo r soils and solid waste include soil vapour extraction , incineration, qps, slurry walls and waste excavation and relocation. Incineration is a very comm on and well-known remediation tec hnology for the thermal destruction of organic materials co ntaminated with organics. In the US , public accep tance of this technology has diminished for various reasons. Soil vapour extraction is applicable to sites with sufficient permeability and with volatile organic contamination. It has been effectively used to remediate a number of sites. Enhancements to soil vapour extractio n are focused on expanding its applicability to a broader range of site conditions and contaminants. Multi-layer surface barriers or caps are routinely used for Resource Conservati on and Recovery Act (RCRA) hazardous waste sites and are designed to provide a useful life of 30 years . The various layers consist of an upper vege tative (topsoil) layer, a drai.nage layer and a low permeability layer, w hi ch may include a synthetic

liner covering a layer of compacted clay.

However, the RCRA caps are failing in terms of preventing water infiltratio n at a significant rate and have limited applicability to arid environments. Slurry walls are another established technology that is used to isolate a contaminated site and prevent further migration.

Their application requires the excavation of soil and blending of the sqil with b ento nite clay. Therefore , dep th is limited by the excavation equipment.

The development of deep soil mixing and permeation gro uting techniques may extend the applica tion of slurry walls. Also, in many applications the permeability requirements for the barrier cannot be achieved with a slurry wall. Another current practi ce for remediating many hazardous waste sites is to excavate the site and haul the media to another site or disposal facility.

It is very lab our-intensive. Worker safety becomes an issue not only with exposure to the hazardous chemicals but also with the handling of solid debris and the personnel protective equipment requirem en ts. Precision excavation equipment is currently not available and therefore , this operation typically results in the excavation of a signifi cant volume of non-contaminated materials. The US Department of Energy has es timated that approximately 70% of all cle;mup costs are associated with the excavation and handling of waste and contaminated sediments. These types of limitations, issu es and technical needs are driving the development of new technologies.

Technologies are being developed w hi ch are designed to significantly lessen worker exposure to handling of waste, place increased emphasis on in situ cleanup technologies, offer permanent solutions and lessen t)'ie generation of secondary waste. These technologies are described in the following sections.

Emerging Technologies for Contaminated Soils Contaminated soils represent a large problem in the US due to the enormous

ENVIRONMENT volume of soil, the range of site conditions and the large list of contaminants.

The primary emerging technologies for remediation of contaminated soils are described below.

Chemical and Physical Solidification is the immobilisation of contami-

nants in a physical and/or chemical binding agen t. Examples of thi s tec hnology include: grout , organic polymers and sorption agen ts. This technology can be applied either in situ or after excavation/ retrieval using above- gro und mixing techniques. In situ chemical and physical solidification can be accompli shed through inj ec tion grouting or deep soil mixing in w hich the reagents are physically agitated with . the contaminated soils in place.

Soil Washing and Soil Flushing is th e extrac tion and/or separa tion of contaminants by the use of water or chemical reagents. In an above-ground applica tio n afte r media excavation/ rem oval, the water or chemical reagents can act to physically separate sm all particle sizes from larger particle sizes.

This achieves a volume reduction of the material that needs to be treated, or it can be u sed to elute more soluble contaminants from the soil for further treatment. In an in situ application, the water or chemical reagents are inj ected into the subsurface to elute contami-

nants from soils. The injected liquid w ith the co ntaminan ts is collec ted , pumped to the surface and treated in an above- ground treatment process.

Vitrification is a thermal immobilisation and destruction technology that immobilises ino rganics and destroys organic materials by converting the con taminated soil into a glass and crystalline structure. This can be done either in place or above-ground after excavation/ retrieval.

Electroklnetlcs is an em erging technology that is being developed and demonstrated for the extrac tion of mobile ionic contaminants. DC electrical current is applied to the soil through a series of electrodes installed in the ground . Water as well as contaminants migrate to the electrodes w here they are collec ted and recovered for aboveground treatment. This technology has been routinely used in the constructi on industry for the dewatering of sludges.

H owever, it is only recently that its potential application for the remediation of contaminated waste sites has been pursued.

Emerging Technologies for Solid Waste Solid was te, also referred to as buried waste, consists of landfills, trenc hes , cribs etc. and contains a large variety of

contaminated equipment , clothing, laborato ry supplies and so on. It also consists of liquid waste disposal units.

There are three rem ediation alternatives for handling solid waste. The first is to isolate the waste to prevent water infiltration and further migration of the contaminants. Isolation of the waste will also permit time for the development of the treatment technologies for solid waste. The second alternative is to stabilise/solidify the waste in situ to immobilise the contaminants in a waste form that can be left in place, thus keeping the waste from further contaminating the underlying soil and groundwater. The third is excavation followed with either above-ground treatment or disposal in an approved facility .

The primary em erging technologies for solid waste include: Plasma technology is thermal treatment technology capable of handling solid waste and is especially applicable to the treatment of contaminated metals. This residue from the process is stabilised as a glass or ceramic waste form .

In situ stablllsatlon is a technology w here a grout is inj ected into the solid waste to solidify it. This also reduces the potential for subsidence at a waste site as a result of the decay of the waste · material.

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WATER JULY/ AUGUST 1997

37

ENVIRONMENT Engineered barriers are being developed with design lives of more than 300 years. These barriers are being designed to minimise the changes for human and animal intrusion , plant root penetration , seismic stability, and wind and water erosion resistance. D esigns for the arid environment require the specification of mu ltiple layers of en hanced barrier materials. These include variou s asphalt formulations, synthetic liners and grout formu lation s.

Wall or subsurface barriers are a physical sys tem that will isolate or contain contaminants in a defin ed zone.

This can be an interim action to prevent furth er migration of contam in ation before treatment or can provide longer term containment and confinement.

Enhanced barrier materials such as viscous liquids , gels, polymers, silicates and mineral wax dispersions are being developed w hi ch will minimi se the cracking of a barrier and enable the maintenance of the barri er sho uld cracks occur. They are also easier to emplace. These materials so lidify at sub surface temp eratures to produce n early inert imp ermeable barriers.

T hese materials are being designed to provide a barrier with lower permeabilities and extend the applica tion to co nta ct with con centrated ch emica l solutions.

Drilling technologies and advancements in barrier materials have led to

the development of horizontal barriers.

This would enable a floor to be placed undernea th a was te site to preve nt downward migration of contaminants Grout walls are a relatively new technology. The grout wall is created by inj ec ting grout directly into the soil using permeation grouting or by in situ mixing of the soils and grout using technologies such as deep soil mixing.

Permeable/ sorbent barriers are being developed for the treatment of gro undwater and to prevent the further migration of contaminants from solid waste sites. These barri ers are located in the vadose zone or aq uifer sediments and minimi se contaminant migration by mixing chemical reagents directly within the barrier materials or placing a layer of reagents next to the barriers.

Ice barriers/cryogenics An ice barrier co nsists of a wall of watersa turated soil that has been frozen , producing a temporary barrier. Frozen soil barriers have been used for many years in the construction industry to stabilise soils aro und an excavation site to prevent cave-in of the walls. When the barri er is no longer needed, the refrigeration is stopped and the barrier slowly melts . These barriers are being developed as an interim barrier for use during waste retrieval (tank sluicing) or deploymen t of in situ treatment techn ologies (soil flushing) to prevent the further migration of contaminants.

BOOKS Free-living Freshwater Protozoa: A Colour Guide D J Patterson. Available from UNSW Press, tel. (02) 9398 8900, fax (02) 9398 3408. Cost: $59.95 'Protozoa are found in almost eve1y habitat from cesspit to mountain stream.' They are an extremely di verse group of unicellular 'animals.'

Together with unicellular algae and sli me moulds, th ey make up the proti sts. They are an important group as significant consumers of bacteria and used as indica tors of water quality due to their response to changing physical and chemical characteristics.

This excellently illustrated book is aimed at students and professionals who need to study protozoa as part of their work . There is an emphasis on tho se animals likely to be encountered in freshwater habitats.

The key relies on observing live organisms (with lots of photographs and diagrams provided) so there is no need for specialised training in staining or preservation tec hniqu es. Th e identification is taken to genus level but references are given for th ose wanting to identify to species.

38

WATER JULY/ AUGUST 1997

A classifica tion key starts with key characteristics of the major groups. A dichotomou s key then takes identification to ge nu s using steps and diagram s or photographs together with descriptive notes. If all else fails yo u can search through the numerous and clear pictures to find your 'beast'.

Th e text provides a thorough coverage of methods for studying and identifying protozoa including: â&#x20AC;˘ how to identify protozoa â&#x20AC;˘ techniques for using the micro scope and for finding , collecting, keeping and culturing protozoa .

T here are even methods for calming di stressed protozoa from gently blowing on them to drugging them!

Finally there is a section on protozoan communi ties including plankton, attached fo rms, benthos and sewage trea tment plant orga ni sm s. The diagram on sewage treatment communities shows the gradation in types.

Protozoa are a neglected group of biota. T hi s text provides an easily digestible method of discovering the incredible diversity and beauty of this important freshwater group .

Dr Robyn Tufr

The ice barrier can be easily removed from a site if desired; w hereas other barrier technology would require physical crumbling and excavation to remove.

Site Characterisation Site characterisa tion is a m ajor hurdle that must be overcome in order to effec tively apply remediation technologies. C haracterisa tion data is required to evaluate and assess technology options and to ensure that remediation is accomp li shed. R emediation activities rely on process monitoring and control system s (part of characterisa tion) to ensure that the operating conditio ns are m et. C haracterisation cos ts are enormou s and current technology is ineffective in many cases for locating waste sites and identifying the heterogeneities in the subsurface.

Risk Assessment Ri sk-based planning and decisionmaking is important in the US and its use depends on the stage of developm ent for a particular technology and the scale of the decision. Most large-scale planning decisions follow the NEPA process w hi ch expli citly consid ers environmental, safety and health risk, along with cost and schedule uncertainty. At the technology level, other factors , primarily cos t, becom e the drivers in decision-making. In the US we are making progress in developing and applying ri sk-ba se d decisionmaking processes . However, there is no single widespread process that is being implem ented.

Conclusions T he problem s in the United Sta tes in cleaning up large volumes of contaminated soils and solid waste require us to advance beyond the existing technologies. Permanent solutions , cost-effective approaches and low-risk alternatives that have a minimum of secondary waste generation are needed. T his is especially true as the US D epartment of Energy addresses the issues associated with its radioactive wastes . Through the collective effort s of industry, university research and techn ology development within government agencies , there are a number of very promising emerging technologies. Due to the large potential cost savings , it is anticipated that the emphasis will be placed on in situ cleanup technologies .

Author Mary E. Peterson is a senior program manager at Pa cific Northwest National Laboratory, USA. Sh e has a background in ch emical engineering and has been involved in numerous hazardou s and nuclear waste treatm ent and disposal programs.

BUSINESS Abstract The law stipulates that di rec tors mu st ac t in the interes ts of ' the company as a whole' and this has traditionally been interpreted as referring to shareholders. However, in recent times, directors are increasingly required to take into account the often conflicting interests of many other stakeholders.

This is well illu strated by the case of the director of a corporatised government bu siness entity who ha s to deal not only with this problem but also with the often conflicting expec tatio ns of the same stakeholder-government-while wearing multiple hats!

Key Words

CORPORATE GOVERNANCE AND STAKEHOLDER .EXPECTATIONS

Corpo rate gove rnan ce , direc to rs, corporatisa tion , privatisation

Introduction It is no t difficult to believe that the modern direc to r mu st be a fairly confused individual. R ecent times have seen the topic of corporate governance and the role of directors raised to an unprecedented level in the minds of the bu siness and wider community.

Admonishments have flowed thick and fas t, as evidenced by this sample of press headlines : • Boards mu st learn to shape up or starve • A stick to bea t bad boards • Directo rs too cautious regarding risk • The board as a social club • ACCC concerned over 'multiple' directorships • Directors can 't hide from 'investor consumerism' The last example points to w hat some have termed the rise of shareholder activism , particularly by large institutional investors . This too has spawned its share of catchy newspaper captions: • The beefs of the biggest investors • Shareholders put on muscle • Battles and backlash of proxy votes What is happening here? Has the law changed? Have society's expec tations moved and, ifso , in w hat respect? What does the modern shareholder want?

Some of these questions are mu ch more easily answered than others. Yes, in some areas the law has changed but the corporate governance debate is much wider than the strict ambit of the law.

Clearly, society's expectation s have changed, but defining them-and tho se of the shareholders- is problematic.

Both these groups-society and shareholders-comprise many sub-sets with often very different agendas . Steering a co urse through the sea of often mutually contradictory or inconsistent

N L Scheinkestel

elem ents is the lo t of the m odern director.

Thi s article reviews some of the eco no mi c thinking underlying the corporate governance debate. It briefly co nsiders internatio nal tre nds, before fo cusing on the role of directors on the board s of corpo rati sed gove rnment business entities (GBEs) in order to highlight issues of conflicting stakeholder expectations and , in the case of GBE directors, often conflicting expectatio ns of the same stakeholder.

Understanding the Economic Framework Until quite recently, thinking on corpora te governance was roo ted in economi c w riting of the 1930s .

Economists such as Adolf Berle and Gardiner M eans commented on the shift of indu strial wealth fro m the ownership by individuals to ownership by corpora ti on s (Berle and M ea n s 1933) . T hese corporation s, in turn , were owned by widely dispersed shareholders who were no longer actively involved in m anaging the business or even in setting corporate policy. A new class of professional managers emerged to provide lea dership . Under thi s model of corporate governance, w hich to some extent still p ersists today, shareholders have beco m e to tally recipients of co rpora te passive outcomes and the director's role, one of This paper won the Michael Flynn Award in the Innovation and Regulation Stream of AWWA's 17th Federal Convention

selec ting th e managers, m o nito ring their performance and replacing them in the event of failure (Linden and R o tenier 1994; Pound 1995) .

The 1980s saw this model played out with often devastating consequences fo r the shareholders and , in fac t, fo r the broader communities in w hich these compam es operated.

Ineffec tive m onitoring of managers by both shareholders and boa rds led , in some cases , to managem en t pursuing strategies primarily in their own interests rather than those of shareholders. As boa rds were often comprised predominantly, if no t exclu sively, of senior m anagement and their mates, the result, as some commentators have put it, was ' the continuation in offi ce of many a chief executive fathead with a captive and cowed board' (Linden and Rotenier 1994). N o do ubt many share holder casualties of the 1980s would consider that to be mild language.

But as early as th e 1970s, the dynamics in the corporate ownership debate bega n to change . In 1976, P e ter Drucker (Dru cker 1976) drew attention to the increasing size and concentration of institutional shareholdings.

At the time institutio ns held approximately 19% of the equity in the America n market; by 1993 their holdings approxi mated 60% (Linde n and R otenier 1994; Bosch 1995) . T he fragm entation of ow ne~shi p w hich formed the basis of Berle and M eans' argument was now being replaced by a reconcentration w hich had the potential to create a new balance of power (B osch 1995) .

'Po tential' was initially all it was, WATER JULY/ AUGUST 1997

39

BUSINESS since for many yea rs these shareholders remained largely passive. When truly dissa tisfied with a company's management, they liquidated their holdings.

However, w ith time, institutional investors began to flex their mu scles. In part , they had little choice. Their holdings had grown and they needed to maintain diversified portfolio s. If management of a major company in a thinly represen ted industry sector failed to perform, selling out was often no longer an option; actively moving to ' fix ' the problem was frequently perceived to be the only alterna tive .

Similar arguments have been advanced in Australia for institutional shareholder intervention in companies .such as Goodma n Fi elder, Pa cifi c Dunlop and Coles M yer.

An interesting sideline to the development of sharehold er activism ha s been the realisation of how vulnerable managements can be. In the ea rly 1990s, the US saw a spa te of exec utive departures at IBM, Westinghouse, American Express and General Motors (to name a few) all prompted by 'enraged institutional shareholders, who dema nded that board directors act quickly to restore confidence in firms that were floundering' (Anon. 1993).

Commentators noted that, in a sense, these departures came too late . The boards of these companies o ught to have acted earlier. But they did serve to show that 'once-comatose boards can be woken up by determined shareholders' (Ano n. 1993) . The success of activist shareholders ha s stirred boards into a more proactive relationship with senior management. As rece nt events in Australi a have shown-Fairfax and State Bank of NSW come to mindCEOs w ho ignore their own boards as a constituency live dangerously (Ries 1996).

While all this agitation was occurring in the boardroom, the term 'corporate governance ' started being bandie d arou nd in the markets and even in some loungerooms. As some have put it, it cam e into usage in order to answer the questions: Who is in charge around here? and For whose benefit? (Linden and Rotenier 1994).

This was particularly empha sised in th e United States when early shareholder activism by major institutions was often directed to the pursuit of social goals. Causes as varie d as apartheid in South Africa, the sinking of the Exxon Valdez off Alaska, the antismoking movement and Ralph Nader's ca mpaign on car safe ty all featured involvemen t by major shareh olders (Bos ch 1995). Some questioned whether this 'crusading' had anything to do with the pension funds' fiduciary duty to their own shareholders or

members (Linden and Rotenier 1994) .

Nevertheless, this approach now has a label. Some have called it ' stakeholder' as opposed to 'sharehold er' capitalism.

Shareholder capitalism states that the esse nce of business is to maximi se profits for shareholders . Stakeholder capital.ism holds that shareholder interests mu st be balanced with the interests of other stake holders such as suppliers, labour, financial institutions, customers and the community in which the company operates (Kaleski 1996) .

The latter proposition is not that revolutionary. In some cases the law has ensured that some of these interests become items on the board agenda. The classic director's obligation to 'act in the interests of the company as a w hole' has be n extend ed judicially in Australia to require directors to co nsi der the interests of creditors w here the company is insolve nt or near insolvency: e.g.

Walker v. Wimborne (1976) 137 CLR 1; Kinsela v. Russell Kinsela Pty Ltd (In liquidation) (1986) 4 NSWLR 722.

The Corporations Law (s. 588G) makes directors personally liable for liabilities incurred at a time when insolvency co uld have bee n susp ec ted.

Environmental legislation in many juri sdictions makes directors automatically personally liable for serio us breaches unless th ey can demonstrate that they have taken appropriate ongoing action.

In ocher areas , developments in management thinking and practices have delivered close working relationships with key stakeholders. 'Just in time ' procurem ent practices and customer requirements in respect of quality accre ditation have enabled stakeholder input and enhanced performance.

Hence the argument by some that many, if not alJ , of these stakeholders, other than shareholders, already benefit from appropriate safeguards or have channels for input: lenders and suppliers have contractual arrangements, as do customers w ho may also enjoy protection through co n sumer legislation; co mmunity standard s are addressed through regulations and legislation and, in the words of one commentator , Owen Green, ' should have no greater position in relation to the governance of corporations than [they have] in the conduct of an individual' (G reen 1994.

Green goes on to argue that designing a system which reconciles the objectives of alJ these multiple groups is nigh on impo ssibl e. Small shareholders may wane security, regular dividends and some grow th ; fund managers may require anything from short-term, high performance stocks to long-term capital growth ; lenders may prefer clients that actively 'work' their acco unt; suppliers

seek a stable relation snip and communities expect positive contributions to their goodwill. Designing a system that would equitably meet all these claims, in Green's view, would tax even a bu siness sc hool professor! (Gree n 1994).

C learly , strategies that appear eminently reasonable to one group may be abhorrent to another. One ca n become so conditioned to a set of values and obj ectives that it is a shock to realise that the same circumstances or facts viewed from another perspective can look quite different. Different stakeholders may therefore view corporate initiatives with different eyes to each other and to the board.

Can a reco nciling sys tem be designed? In Owen Green's view, ' the experienced and pragmatic corporate practitioner realises that the ultimate requiren1ent from any such design is chat it does not impede the pursuit of profitability, without which any and all the other interests become substantialJy irrelevant' (Green 1994).

International Trends What of other jurisdictions? How does the Anglo-Saxon model of corporate governance compare with others?

The US, UK and Au~tralia have largely followed the shareholder capitalism model, while the stakeholder model has predominated in Germany, mu ch of Europe and J apan (Kaleski 1996, 23).

Results are inconclusive in that many factors affect the results. The German model involves a two-tier board system: an executive board and a supervisory board. Labour as well as maj or shareholders and fina nciers are represented on the supervisory board. However, the financiers are also often major equity holders and, as in Japan , are often direct business partners of the firms in which they hold large stakes. Such a degree of involveme nt may well justify more direct control over the firm in question but stop s short of req uiring actual management of the firm itself. For such investors , membership of a supervisory board appears to offer an ideal soluti on (Green 1994).

Sir Adrian Cadbury, author of the influential Cadbury report on corporate governance in the UK, has been quoted as saying that future reforms in the European Community may well pursue a converge nce between the European and Anglo-Saxon models of governance (Green 1994). The difficuJty with this approach is that it appears to ignore very fundamental differences in the equity structure of the two systems. Further, fo llowing on so me recent spectacular failures of European corporate governance, one wonders whether the proposition still carries the same cachet.

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41

BUSINESS The followi ng case study drawn from Graff and Lorsch (1995) may help illu strate some of the issues.

M etallgesellsc haft Aktiengesellschaft (M G), one of Germany's largest industrial gro ups, fo und itself in serio us trouble in 1994 as a result of a hedging strategy which had gone terribly wrong.

Its management or executive board comprised seven individuals, and was very much dominated by its charismatic Chairman, H einz Schimmelbusch (in the Anglo-Saxon model, Schimmelbusch would have been the CEO). Schimmelbusch, in turn , reported to the Supervisory B oard w hich consisted of 20 members. T he shareh olders elected ten ; company employees elec ted seven from the ir number and three were officials from the company's unions. The Supervisory Board met three or four times a year and was chai red by Ronaldo Schmitz, a director of Deutsche Bank. Key shareholdings were as follows:

Top 5 MG Shareholders

Interest %

Deutsche Bank & Dresdner Bank

25

Gen Adrnin Industrial Holding Company

25

Kuwait Investment Authoriry

20

AMP

5

MIM

1

As the story ultimately unfolded , there appeared to have been gross failures in corporate governance, however defined and in whatever cultural context you choose to place it.

All information to th e Supervisory Board was channelled through the CEO-as many would remember, a device su ccessfully u sed by J ohn Friedrich here in the infamous N ational Safery Council saga. When Schmitz asked for copies of the minutes of the management board meetings, the CEO gave him summaries and Schmitz apparently accepted these. Financial statem ents failed to adequately di sclose high levels of realised losses w hich mounted through 1993 and , w hile it might have been expected that problems would have been uncovered by links between the company and Deutsche Bank which was apparently intending to offer products based on the MG hedges, nothing apparently surfaced or was acted on.

By the time Schimmelbusch was fired, MG 's total indebtedness was estimated at Dm 9 billion. Creditor banks-predominantly D eutsche and Dresdner-agreed to a Dm 3 .4 billion restructuring w hich involved debt for equiry swaps and the issue of new 42

WATER JULY/AUGUST 1997

equity. T he .Wall Street J ournal heightened awareness by directors that commented: 'This decision extends a they will be personally liable if they fail tradition in which Germany's big banks to adequately inform themselves. th row out a safery net w hen a maj or H owever, the end result is clearly better company gets into tro uble' (Roth information fl ows. Further improve1994). When yo u control 25% of the m ents can always be made and , regretcompany and your director is up to his tably, cleve r frauds will still be perpeneck, perhaps the strategy is not that trated. surpnsmg.

On the other side of the world , the At MG's shareholder meeting in J apanese model of corporate governance 1994, following revelations of the has been very much a product of the hedging disaster, Schmitz told share- 'keiretsu system'-networks of interholders that M G's problems were a connected associated companies w here unique incidence of wrong-doing and nearly all directors are senior managers that they did not reflect on the efficacy or fo rmer employees. Until recen tly of the two-tier board system. shareholders played virtually no role Shareholders were apparently less than except to provide capital. Power has convinced, citing informatio n that 60% been totally concentrated in the hands of supervisory board members in the 30 of the president/c hief executive and an DAX index companies are management operating committee. The firms have board members of ocher DAX Index been run as much for the benefit of the companies (Choi 1994). employees and those of their alli ed Some (Turnbull 1993, 229-30) have companies as for shareholders (M onks proposed that use of supervisory boards and Minow 1995 from w hich much of would cure the red uction and distortion the following discussion is drawn). in information received by the single The Japanese system has had little unitary board in the Anglo-Saxon need of formal channels for the provisystem. T he argument is that informa- sion of informa tion to directors, since tion moving from the board down the most of them are m anagers. The organisation is necessarily 'big picture,' 'bottom-up' decision-making approach that it needs to be interpreted by subor- ensures that concerns of subordinates dinates and that it is therefore prone to are factored into the process, but for distortion. Informa tion corning to the anyon e w ho has negotiated with a board, on th e och er hand , needs co be Japanese company i'c is also clear that simplified and condensed and suffers this approach is often at the cost of fas t from the confli ct of interest created for response and fl exibiliry. those down the line w ho need to report It is acknowledged that changes are on problems for w hich th ey might afoot in Japan. Until recently, employappear to have responsibiliry. Further, it ment creation was seen as a principal has been suggested (Turnbull 1993, corporate duty, but even this is begin232) that the two-tier system avoids the ning to change under eco nomic confli cts of interest experienced in the pressures.

Anglo-Saxon m odel.

Internationalisation and liberalisation The MG case provides no evidence of Japan's financial m arkets are opening that the two-tier board system is intrin- up new avenues of finance to large sically any better equipped to deal with J apanese companies. This could have a information problems than the Anglo- major impact on the keiretsu system.

Saxon unitary board. Similarly, the J apanese banks have previously been statistics referred to earlier-that 60% very influential members of the of supervisory board members in the 30 keiretsu, not only due to the traditional DAX index companies are management cross-shareholdings, but also as a result board members of other DAX index of staff often seconded into key financial companies-belie any suggestion that positions with client firms.

Bureaucratic control is also under conflicts of interes t are not present in the German m odel. Indeed , m pressure. Government's traditional Australia, the emphasis in recent times approach towards J apanese business as on the appointment of genuinely promoter and protecto r rather than independent non- executive directors to impartial regulator has been criticised boards and the separation of the roles of following securi ties and banking chairman and chief executive appears to scandals . T he common practice of retirhave delivered significant improve- ing bureaucrats taking board positions ments in these respects over some inter- on companies they previou sly regulated national models. Increasingly, directors (called 'amakudari' w hich apparently are requiring a range of executives, translates as ' descent fron'i heaven') has rather than just the chief executive, to come under scrutiny (Babcock 1993, 8; make presentations regularly to the Monks and Minow 1995 .) Japanese life board and directors are undertaking site insurance companies have become an visits to see operations first-hand and important so urce of new funds and are meet employees and customers. N o now featuring as both major shareholddoubt, this process is encouraged by a ers and creditors. They are undoubtedly

BUSINESS gaining a larger, if as yet still undefined, role in corporate governance. As with many developed countries aro und the world , Japan is facing a rapidly aging population. T he greying of Japan w ill clearly put pressure on life insurers and pension funds to improve their yields on investments and this is likely to provide a maj o r imp etus to their ass umption of a m ore active corporate governance role.

J apan was n o t immune to th e excesses of the 1980s and the public backlas h that occurred aro und the world in response to rogue corporate behavio ur was similarly experienced there. P rosecutio ns have fo llowed and legislative changes have occ urred in areas such as increased disclosure. So, while many have previously thought the Japanese model as worthy of adaptatio n elsewhere, its m erits are now in question and significant change appears to be under way.

GBEs and Corporate Governance H ow does the discussio n to this point fit with the topic of GBEs and corporate governance? D oes government ownership make a difference? In order to answer thi s, it seem s appropriate to re turn to the qu estion of w ho determines the purpose of the fi rm and w ho makes the choice of opting for shareholder or stakeholder capitalism .

One writer in this area, Andrew Campbell , analysed the issue (Campbell 1993) by fi rst con sidering a threeperson consulting business specialising in advice o n bu siness strategy and comprising two principals and an administrative assistant. What is a legitimate purpose fo r such an enterprise?

M aximising shareholder wealth? Longterm survival? Providing a stimulating work environment? T he answer is that it depends on the aspirations of the two principals. C hoice of business purpose is the respo nsibility of the owners/ managers w ho crea ted the fi rm , subj ect, of cou rse, to n ormal bu siness constraints such as the law, ability to cover costs and so on.

If the firm increases in size to employ 3000 people but is still controlled by the two principals, no thing changes. T he situation does change if the firm goes public and ownership and management are separated. At thi s point , in the abse nce of stipulated obj ects in the company's constitu ent documents, it is up to management and the board of directors to selec t business obj ectives.

Anita R oddick and her boa rd at T he Body Shop have favoured foc using on other than simply shareholder value.

T he company's obj ectives are fi rst, 'To discharge the responsibility as leaders in our trade ... ' 44

WATER JULY/ AUGUST 1997

It is not until one reaches the fifth obj ective that shareholder returns get a mention: 'T o generate sufficient profi t to fi nance continual improve ment and growth of the business w hilst providing our shareholders with an excellent return on their investment.'

In the corpo ratisation of GBEs in the wa ter and elec tricity indus tries in Victoria , and particularly in the case of electricity primarily while it remained w holly government-ow ned , ownership and m anagement have been separated.

Or have they?

In the Government's blueprint for reform of the metropolitan water industry, (Office of State O w ned Enterprises 199 5) the three key reform obj ectives were to : â&#x20AC;˘ increase efficiency. â&#x20AC;˘ maximise customer benefit. â&#x20AC;˘ reduce Victo ria's debt burden .

T he businesses were to 'assume a commercial fo cus' but customers would be 'protected , through the Office of the R egulator General and conditions set o ut m the bu sinesses ' ope rating licences ' (Office of State Owned E nterprises 1995, 3).

T he document goes on to state, 'The bu sinesses have been established as State owned companies because this corporate form best replicates a commercial operating enviro nment. T he foc us of each business is attaining best practice,' and later, 'The State owned company form allows a company m aximum independence fro m Government.

T here is a clear fra mework of accountability to Government fo r State owned companies, through standard constitutions requiring the memorandum and articles of association .. . to be consistent w ith Government obj ec tives . The Government is the sole shareholder of the company . Within thi s "global" framework , and subj ec t to overall Government policy and agreed business and strategic plans, State owned companies have management autono my and the respo nsi bility to opera te on commercial prin ciples' (Office of State O w ned E nterprises 1995, 5) .

There are quite a few provisos there, but there is an unambiguous bottom line. And , indeed, it is tru e that in a number of respects the newly forme d retail wa ter companies were more independent than , fo r exa mple, the electricity distribution companies w hen they were first establi shed.

T he elec trici ty reform blueprint (O ffice of State O wned E nterp rises 1994) went along m uch the sa me lines as that for water. If anything, the obj ectives were even more commercially focused , including 'more price signals' to encourage demand management , 'improved investm ent decisions,' and clear commercial foc us' (Office of State

O w ned Enterprises 199 4 , 6). The document repeats in a number of places that the businesses are to 'operate on a fully commercial basis at arms length fro m Government under independent professional boards of di rectors' (O ffice of State O wned Enterprises 1994, 6 and 22).

It was therefore not surprising that it initially came as something of a shock to many of the new electricity company directors that relations were not quite as 'arms length' as so me had expected .

The Treasurer had i:etained, by legislation , a right of direction that could be used to override directors and require them to act in a specified way .

Government observers were prese nt at all board m ee tings. They were no t board members and carried no responsibility for board decisio ns.

Interestingly, neither of these fea tures was adopted in the water reform process.

As I was a board m ember of bo th one of the electricity companies until it was sold and am still a director of one of the wa ter retail companies , I will hazard an explanation fo r the diffe rences and offer so me comments on my experience . I hasten to add that I speak in an entirely personal capacity. I think the much greater control of the electricity process had m uch to do with the privatisation agenda. T he companies were to be sold and on a relatively tight timeframe. In the case of water, the Premier has declared that no privatisation is on the agenda at least until 2000. In the final eve nt, the unexpec ted , indeed unwanted and stro ngly resisted, tentacles of government referred to earlier proved highly desirable and beneficial in the elec tricity reform p rocess . The government observer, at least on my board (M s Sally Farri er), provided an invalu able bridge betwee n a highly commercial and focu sed board and the sometimes (at least to us) inexplicable processes of the bureau cracy. T he commercial world and the bureaucracy can , at times, seem like di fferen t countries. The government observer acted as an in terpreter, represe nting each party to the other and overcoming real cultural and language difficulties.

T he Treasurer's right of direction also prov~d its worth . T he companies in both the water and electricity indu stries were established with the assistance of a legislative m ec hani sm known as an alloca ti o n statement. When large monopolies such as the former State Elec tricity Commission qr M elbourne W ater are disaggrega ted , assets can be transferred by this m eans - effec tively a legislative deemed sale - to minimise tran sac tion costs. T he instrument can be a little blun t. Historic info rmation is not always complete or accurate , so the initial allocation stands a fair chance of

BUSINESS being w rong. In additio n , many problems may only become apparent once the new boards are in place and beginning to concentrate on the detail of their business . This proved to be the case in the electricity process and considerable difficulty was avoided by being able to deal with these adjustm ents by way of the T reasurer's direction .

In its absence, and no such ge neral right of direction has been retained in the case of water reform , one may be faced with a situation w here an inappropriate benefi t has been conferred on one company w hile another has been disadvantaged. To expect the directors of the advantaged company to readily relin. quish their benefit fo r the sake of the broader industry reform agenda does no t appear consistent with them acting in the interests of ' their company as a w hole' even though it may be desired by the sole shareholder.

R econciling the reform obj ectives stated in bo th the electricity and water blueprints has no t always proved easy.

As stated earlier, particularly in the case of electricity reform , the admoni shments to act commercially were very stro ng. Under private sector owners, who have paid full prices, the imperative to do so must now be even greater.

Yet recent reports have seen some of the electricity distribution companies castiga ted by the R egulator General fo r the number of power disconnections for non-payment (Skulley 1996). Mr D avey was quoted as saying that such performance was 'simply n o t goo d enough in circumstances w here ... (the company) is announcing profits over and above those proj ected for it by the Government.' It does not appear from th e report that the company was in breach of any of its licence conditions in so ac ting. Its 'crime' of disconnec ting too m any non-paying customers was som ehow aggravated because it had the tem eri ty to excee d gove rnment fo recasts.

Is the situati on different if the company is government or privately owned? In the water industry , disconnec ti ons are not allowed for health reasons but the companies are permitted to restrict supply to the minimum required fo r hygienic purposes. Thi s can mean little more than toilet flu shing and probably no t too many toilets at that. It is convenient that, in thi s area, political and commercial con siderations may well coincide, as it is likely that the more significant accounts in monetary terms will be industrial or commercial customers rather than dom estic ones.

Aggressive pursuit of these as a priori ty can therefore meet commercial criteria without attracting the opprobrium of the R egulator General.

E qually, comtructive trea tment of custom ers experiencing hardship may be a necessary part of a utility business and an important aspect of its positi oning in the industry. But lax managem ent of bad debts will no t achieve effi ciency and will certainly n o t con tribute to profitability that w ill reduce the State's debt burden . The government does assist people experien cing hardship th ro ugh co ncessio n program s and may ultimately need to supplement this if it wishes radically different criteria to be appli ed to do m es tic custom ers than to other ca tegories.

Similar situations apply across a range of business issu es . T o w hat extent should GBE directors be free to determine their attitude and approach to indu strial relati o n s, especially if a conflict is likely to arise at a . time of political sensitivity? Absenteeism was at stratospheric levels in some of these enterprises w hen fi rs t set up . In some cases , it brought to mind a caption on a T - shirt for sale in Washington: ' I used up all my sick days so I phoned in dead. ' Handling issues such as these and other restrictive working practices required management of culture change , education and involvem ent of the workforce and the unions w hile keeping government and bureaucrats informed and onside. And at times that meant different government departments with different agendas .

The question of executive and director salaries is another issue of some contention . If 'best practice' is an obj ective, then government as shareholder needs to compete with the private sec tor in w hat it is prepared to pay fo r top calibre people. Thi s can cau se considerable strain within the bureaucracy if salaries are perceived to be out of kilter with those of senior public servants. Equally , the 'Cedric, the pig' stunt at the AGM ofBriti sh Gas was the type of public relations nightmare that no company can afford to be saddled with. 'Cedric' was a pig hired by the UK Trades Union Council and named in honour of Cedric Brown , a direc tor of British Gas . ' Cedric' was brought to the AGM and fed out of a bucket daubed with the words 'share options' to highlight the unions' displeasure about significant increases in director salaries w hile massive retrenchments and reductions of salaries were being experienced by the company's labour fo rce.

An adequate re turn to equity is clearly a corporatisation obj ective . The government receives its return through a combinati o n of tax equivalent paym ents and dividends. These paym ents are clearly an imp ortant source of reve nue for the government

and the appropriate level of dividend can be a topic for robust debate between the boards and the shareholder. From the board's perspective , there are many valid claims on these funds: the capital program on an age d asse t base is sub stantial and could always be increased ; debt reduction is a stipulated reform obj ec tive; improvem ent of information system s and other service aspec ts of the business are all on the priori ty list. M any of these are also important for the gpvernment and it must prioritise these claims in deciding h ow much of these funds to leave w ithin the businesses and w hat level of debt is appropriate . T he other important elem ent in the equation is that prices are regulated . On present arrangem ents, the water compani es have virtually no ability to increase pri ces to fund improved or added services.

The difficulty for b o th partiesgovernment ¡ and boards-is that the public, and perhaps even the regulator, may no t always make the appropriate linkages . From the perspective of a company required to distribute a higher level of profits than it thinks appropriate and unable to maintain w hat it believes is the necessary level of capital expenditure, neither the public nor the regulator may realise it had 1ittle choice in the matter if increases in spillages occur as a result. From the government's perspective, on the other hand, leaving the funds with the businesses m ay appear a flawed decision if performance remains nonetheless poor and the m edia blames it on the government's commitment to the corporatisation program .

Conclusion The answer? I do not think there is one. None of the established models of corporate governance has an unblemished record. While the European and Japanese m odels of stakeholder capitalism were for some time thought desirable to be followed, recent questions have been raised about the lac k of independence within their structures.

As one commentator put it, 'The genius of the American corporation [and I think it can equally be attributed to the Australian model] is creating a system w here power resides outside the executive office. So if the chief executive is to tally out of w hack , some force outside m anagem ent can act' (Linden and Rotenier 1994).

Equally, it has been 119 ted that this approach must be used with caution: 'Boards will sometimes n eed to interpose them selves between impatient shareholders and managem ents w ith intelligent long-term plans ... The last thing in the w orld that you want to do as an own er is to discourage chief WATER JULY/ AUGUST 1997

45

BUSINESS executives from taking risks. So, while th ere is a nice, healthy tension now, there's a danger of going too far' (Linden and Rotenier 1994).

The same undoubtedly ca n be said for GBEs. A healthy tension exists between government as shareholder, government as communi ty watc hdog and politicians with a consti tu ency on one hand and the boards of these enti ties on th e other. GBEs are expected to act commercially, strive for best practice, achieve efficiencies and deliver adequate returns to the share hold er-government. Equally, and und erstandably , government is concerned at possible political fallo ut from the actions of over-enthusiastic GBE directors intent on implement-

ing everything from changes in industrial practi ces or aggressive debt management of disadvantaged customers. T en sions exist between competing claims on surplus funds: should they be ploughed back into the businesses, used to lower prices, or returned to the governrn.ent?

Whether in the priva te or public sec tor, directors must take account of vary111g stakeholder expec tation s.

They are required to do so by law in many areas and in others, it is just part of good bu siness prac tice. Paying heed to broader issues will often directly contribute to profitability. However, at the end of the day, if these organisations are not to be propped up artificially, profitability ought to remain

the key goal. As Owen Green said, in its absence, 'all other interests become substantially irrelevant.'

For th e GBE director, clarity of purpose is fundamental to the exercise . Objectives must be clearly articulated and agreed with government as shareholder and enunciated to the wider community. Sensitivity to the roles, vulnerabilities and perspectives of each requires constant reassessment of strategies and approaches and open and regular communication. If ever there was a place for a ' no surprises' policy of information flow, this must be it. Add flexibility, pragn1atism and, in my view, a good dose of schizophrenic tendencies, and you have the makeup of the ideal director of a GBE.

References Anon. (1993) Getting Rid of the Boss. The Economist: 13.

Babcock, B. (1993) Seeds of Change in Japan.

The Corporate Governance Advisor f2: 1.

Berle, A. and M eans, G. (1933) The Modern Corporation and Private Property.

Bosch, H. (1995) The Director at Risk: Accountability m the Boardroom.

Campbell, A. (1993) A Brief Case: The Purpose of the Firm. Long Range Planning 26(6): 140-1.

Choi, A. (1994) Shareholders Give Approval to M eta11geseil sc haft Plan. The Wall Street Journal, New York.

Drucker, P. (1976) The Unseen Revolution: How Pension Fund Socialism Came to An1erica.

Graff, S. and Lorsch, J. (1995) Governance at Metallgesellschaft. Boston, Harvard Business Schoo[ Green, 0. (1994) A Simple Aim and a Single Board. Director 47(9): 38.

Kaleski, M . (1996) A New Capitalism Cometh.

Company Director: 22.

Linden, D. and Rotenier, N . (1994) Good-bye to Berle and Means. Forbes 153: 100, 100-3.

Monks, R. and Minow, N. (1995) . Corporate Governance.

Office of State Owned Enterprises (1994) RefoIT11ing Victoria's Electricity Industry: A Competitive Future for Electricity. A Summary of Reforms, Department of Treasury, Melbourne.

Office of State Owned Enterprises (1995) Reforming Victoria's Water Industry: The Restructured Metropolitan Industry, Department of Treasury, Melbourne.

Pound, J. (1995) The Promise of the Governed Corporation. Harvard Business Review: 89, 90.

Ries, I. (1996) Why Mansfield Was Sacked.

Australian Financial Review: 18 April.

Roth, T. (1994) Metallgesellschaft and Creditor Banks Agree to Financial-Rescue Package of $1.84 Billion. The Wall Street Journal, Europe: 6 January.

Skulley, M. (1996) Cut it out, United Energy Warned. Australian Financial Review: 22 August.

Turnbull, S. (1993) Flaws and Remedies in Corporatisation and Privatisation Human Systems Management: 12: 227.

Author Nora Schelnkestel is a lawyer and financier whose board appointments include City West Water,' The Energy Research Development Corporation, Snowy Hydro Trading Pty Ltd and North Limited and MDBC's Water Business Committee. She has had a major involvement in utility industry reform and is a Senior Associate at the Melbourne Business School.

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WATER JULY/ AUGUST 1997