Page 1


Volume 25 No 4 July/August 1998 Journal Austra lian Water & Wast ewater Association

Editorial Board F R Bishop, Chairman

B N Anderson, G Cawston, M R Chapman P Draayers, W J Dulfer, G A Holder M Mumisov, P Nadebaum, J D Parker AJ Priestley,] Rissman, EA Swinton

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

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

CONTENTS

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

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

Branch Correspondents

POINT

OF

VIEW

ACT - Ian Bergman Tel (02) 6248 3133 Fax (06) 248 3806

The Challenge of a New Water World ........................................................... 3

New South Wales - Mitchell Laginestra

C PolJett

Tel (02) 9412 9974 Fax (02) 9412 9676

WATER

Northern Territory - Mike Lawton

.

Tel (08) 8924 6411 Fax (08) 8924 6410

Queensland - Tom Belgrove

1998 Stockholm Water Prize Winner ....................... .. ................................. . 8

Tel (07) 3810 7967 Fax (07) 3810 7964

G Winerantz-Wernstedt

South Australia - Angela Colliver Tel (08) 8227 1111 Fax (08) 8227 1100

Tasmania - Ed Kleywegt

'l

Water in the Great Artesian Basin .................... ........ .............. ............ ..... 9

R Cox, A Barron

Tel (03) 6238 2841 Fax (03) 6234 7109

Rural Water Treatment in South Australia .. ...... ........ ..... ... .. ........ .. ............. 14

Victoria - Mike Muntisov

EA (Bob) Swinton

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

Western Australia - Jane Oliver Tel (08) 9380 7454 Fax (08) 9388 1908

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Riverland's CITECT SCADA System .............................................................. 17

D Steele

·

Cryptosporidium and Water: What Do We Know? ................. .................... 18 B R obertson, M Sinclair, M Hellard, C Fairley Cryptosporldlosls from Public Swimming Pools ...... ................................. 20

D Lightbody " Phosphorus inputs to a Reservoir in Orange, NSW ...... .. ................ ..... . 21 M H Chowdhury, DA Bakri WASTEWATER

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ENVIRONMENT ·, Environmental Arsenic In Rural Victoria: An Update ............................ 34

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" Environmental Monitoring Data-Why? How? And What Do We • Do With It? ................................................ ... ... ... ... .................... ............ ..... .... 37

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J C ugley Community Consultation at Agnes Water ........................................ .......... 41 L Miller BUSINESS Mining In The Great Artesian Basin ...................... ... .. ... .... .. ..... ... .. .............. 43

P Bowman ·, Groundwater Pollution: Can Right Markets Help? ..... .. ......................... 44

M D Young, R Evans DEPARTMENTS International Affiliates .. ................. ... ............................ ... .... .......... .... .. ...... ... 5 From the Bottom of the Well .... ........ ................... ....... ................................... 4 Letters ............................................................. ... ........... ... ....... .............. ........... 6 Meetings ........................ ... ..................... .. ............................ ............ .............. 48 OUR COVER: Located on th e banks of the River Murray, Riverland W ater's

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m

WATER

WATER IN THE GREAT ARTESIAN BASIN R Cox, A Barron

This paper is an edited version of a paper p resented to O utlook 98, a conference run by the Au stralian Bureau of Agricultural and Resource Economics and published in the P roceedings of the National Agricultural and R esource Outlook Conference available from the Australian Bureau of Agricultural and Resource Economics, GPO Box 1563, Canberra ACT 2601.

Abstract The sandstone aquifers of the G reat Artesian Basin have provided reliable, good quality water supply to vast areas of arid inland Australia for more than a century. The dominant user of water is th e grazing indu stry, with towns, mining and irrigation supplies currently using approximately 12% of the total extraction. Currently flow from the Basin exceeds the rate of recharge. As a resul t artesian pressures are falling, alt hough the system i s ap proac hing hydraulic balance. This paper su mmarises the current water extraction and resulting impacts and points to management options that can reduce impacts.

Introduction Underlying an area ofl ,700,000 km 2 or approximately one- fifth of Australia, the Great Artesian Basin (the Basin) is the largest artesian groundwater basin in the world. It extends beneath the arid and semi-arid parts of Queensland, New Sou th Wales, South Au stralia and the Northern T erritory and stretches from the Great Dividing Range to the Lake Eyre depressio n . Although the exten sive permeable sandstone beds of the B asin con tain an estimated 8,700 million M L of fresh water, the volume available fo r sustainable use is m uch smaller. The Basin is nevertheless an important resource for many town s and industries in ari d outback Australia.

Hydrogeology T he B asin was formed 100- 150 million years ago. It is comprised of the Carpentaria, Surat and Eromanga subbasins. Initially sediment was deposited in each uni t separately. H owever, with time, th e sediment ove rflowed the divides, fo rming one continuous basin . Sediments are up to 3,000 m thick. Deposits occurred in a n umber of cycles. As a result, the Basin consists of layers of coarse sandstone with high transmissivi ty, alternating with low porosity shale and m udstone. The aquife rs of the Basin are permeable sandstones which are for the most part confined by overlying impermeable rocks. These aquifers are recharged by rai nfall infiltrating into the uplifted sandstones on the edge of the Basin such as those forming the G rea t D ivi ding Ra nge, w h ere unconfi ned conditions exist. Because the recharge area is of a high altitude, and the aquifer is confined, a bore drilJed into the aquife r w ill flow naturally to the su rface. Only about one per cent of the rain falling in the recharge area enters the artesian system because the capacity of the sandstone to transmit water is not large. Excess infiltration disc harges localJy as base flow to streams, evapotranspiration and local springs. Water flow in the Basin is generally westward. In the northern part of the Eromanga sub-basin flow divides to flow ei ther north towards the Gulf of Carpentaria or south towards Lake Eyre. The flow of water is slow. T he water in the cen tral part of the Basin has an age of more than o ne million years. Thi s is consistent with a flow rate of two metres per annum.

Springs The m ost obvious forms of natural discharge are the springs located mainly in the south-weste rn m argin of the Basin (see Figure 1). The springs in the

recharge areas occur because infiltration through the soils is greater than the capacity of the aquifers to transmit water through the aquifer system. In the discharge areas artesian springs may occur where faults o r similar features provide pathways for the flow of water to the surface. T here are approximately 600 recorded springs (H abermehl, 1982). T hey are generally concen trated in clusters near the western and southern margins of the Basin (Ponder, 1986). Many of the springs have developed conical m ou nds. These so- called 'mound springs' were initially formed by the deposition of minerals as the spring water evaporated. Later deposits of wind-blown dust and sand particles trapped by vegetatio n growing around the springs contributed to the accumulation of material. Total flow from all springs in 1982 was estimated at 47,000 M L/a (H abermehl, 1982).

Vertical Leakage A less obviou s maj or fo rm of discharge is slow leakage up through the confining beds. Vertical leakage probably occurs over extensive areas of the Basin and although the rate of leakage per unit area is small it involves considerable volumes o f water. Obviously it is very difficult to estimate the amount, but it is likely to be of the order of 400,000 ML/a.

Water Quality The quali ty of groundwater is good in the B asin's m ain aquifers, with total dissolved solids typically ranging from 500 to 1,000 milligrams per litre. Salinity values tend to increase in the direction of flow. The water is generally suitable for domestic use and stock watering, although in som e cases fluoride levels can be too high even for stock. T he waters in the shallow aquifers above the main aquifers tend to be WATER JULY/AUGUST 1998

9


WATER saline, and may contain more than 10,000 milligrams pe r li tre total dissolved solids. This water is usually too saline for domestic use but adequate for stock.

Development of the Artesian Water Resources Initial Development With the development of the grazing industry in inland Australia a need arose for reliable groundwater supplies. This need was accelerated by drough ts, esp ecially in the late 1800s. In New South Wales the first artesian bore was constructed adjacent to the margin of the Basin near B ourke in 1878. Initially the areas targeted for the d rilling of artesian bores were restricted to development corridors marked by railway lines, towns and stock routes. In time, continued drilling and geological investigations led to the discovery of artesian water in many parts of the arid interior of the Basin, greatly assisting th e d evelopmen t of the pastoral industry. Artesian bores were allowed to flow unchecked , discharging water down bore drains or creeks for distribution to stock. This is a very inefficient system for flow di stribution, with 90% of the flow being lost to evaporation and seepage. However , it was the only practical option at the time. Even w here bores were fitted with valves to control flow , the bo re construction methods and materials of the day were not able to seal the annulus around the bore casing adequately, so it was not long before leaks occurred, corrosion set in and the bores became uncontrollable. The drilling of new bores continu ed steadily. As a result of the release of artesian water from the bores, pressure started to decline in some regions. Some artesian bores ceased flowing and pumps had to be installed to raise the water to the surface . From 1915 reduction in flow resulting from loss of pressure exceeded the discharge from new bores. As a result, discharge from all bores peaked in 191 5, even though bore con struction continued. Total discharge from bores continues to fall, although at a decreasing rate (see Figure 2). Some 4,700 b ores have been constructed in the Basin (see Figure 3). When recent projects to repair bore infrastructure began it was estimated that 1,270 bores needed to be repaired. Around 32,000 kilometres ofb ore drain still exist throughout the Basin. Post-war Controls for Pastoral Bores in the Basin By the middle of the 20th Century the essen tial elements of the flow 10

WATER JULY/AUGUST 1998

system were well understood. By then bore construction techniqu es had developed sufficiently so t hat t he annulus between the bore casing and the hole could be reliably sealed to prevent leaks. As a result, the state governments regulating the use of the water adopted policies requiring tha t new bores be fully controlled and that water be piped to stock. However, the existing uncontrol-

lable bores and bore drain s were allowed to continue to operate. It was recognised that although pressures would continue to fall, they would do so at an ever decreasing rate and Basin pressure would eve ntually stabilise when discharge dropped to the rate of recharge. It was accepted that more bores would stop flowi ng over time and that flow rates in other bores would dimin-

... -

Great Artesian Basin

-

Intake area Concentration of springs

~-

Direction of flow Structural ridges

NORTHERN TERRITORY

SOUTH AUSTRALIA

Figure 1 Hydrogeology of the Great Artesian Basin

Number of flowing artesian bores drilled Artesian bores still flowing Di scharge from all flowing artesian bores

z

~ ID ::;; 0

a:

IL

w

C,

a:

<

:i:

~

c

en w

a: 0

ID

1900

1920

1940

1960

YEARS

Figure 2 Construction of bores and changes in total flow rates

1980


WATER ish, necessitating the establishment of replacement water supplies. The alternative was to reduce fl.ow by requiring that bore drains be replaced by piped systems. It was reasoned, however, that the cost of replacing existing drains with the pipe technology available at the time (galvanised iron), exceeded the cost of establishing new earth dams or other water supplies to replace the supplies likely to fail (Queensland Government, 1954). Recent Infrastructure Renewal In recent decades pipe technology has developed substantially. P olyethylene pipe is easy to handle and lay and can cope with high- temperature artesian water. Bore investigation and repair technology has also developed substantially. As a result, renewed interest has emerged in reducing the waste of water from uncontrollable bores and bore drains to prevent further decline in artesian pressure and avoid further negative environmental and cultural impacts. Piped systems also allow property management p ra ctices that improve productivity. A bore repair project began in South Australia in 1977, with the cost shared by the State and Commonwealth Governments. To date only bore repair works have been carried out, with no replacement of bore drains with pipes. In Queensland a bore repair project began in 1989. The cost of these works is shared between the State and Commonwealth Governments and the bore owner in the ratio of 40:40:20. A separate project to replace bore drains w ith piped systems began in 1994. However, this only operates over part of the Queensland section of the Basin. Although cost sharing was initially on the same basis as the bore repair project, the cost of works is now shared between the State and Commonwealth Governments and the bore owner in the ratio of 28:28:44. In N ew South Wales a bore repair project began in 1989. In 1993 the project was extended to include the replacement of bore drains with piped systems, and from that time only applications for both capping and piping components were eligible for consideration. The cost of works is shared between the State and Commonwealth Governments and the bore owner in the ratio of 40:40:20 for the bore repair component and 10:10:80 for the bore drain replacement component. However, there are moves to increase this level of subsidy. In total, 482 bores have been repaired or replaced, representing 38% of the 1,268 bores considered to be in need of repair at the commencement of the projects. Table 1 summarises the

Table 1 Repair of pastoral bores and replacement of bore drains

Bore repair Bores repaired Flow saved Expend iture Cost per bore Cost per megalitre/a saved Bore drain replacement Systems insta lled Volume saved Expenditure Cost per system Cost per megalitre saved Totals Expenditure Flow saved Cost per megalitre saved Government expenditure Government cost per mega litre

Unit

SA

Qld

no. Ml/a

207 38,000 4,655 23,000 122

250 35,000 10,500 42 ,000 300

0 0 0

12 4,000 2,184 182,000 570

$'000 $ $ no. ML

$'000 $ $ $'000 ML $ $'000 $

4,655 38,000 122 4,655 122

12,684 39,000 325 9,965 255

NSW

Total

25

*

1,887 75,500

482 73,000+ 17,042 33,000

*

-

23

*

4,079 177,500

35 4,000+ 6,263 179,000

*

-

5,966 1,477 4,040 2,703 1,829

23,305 78,477 297 17,323 221

* In New South Wales bores are repaired and drains replaced at the same time. As a result the flow saved by the separate component is not available

infrastructure renewal works that have Water Extraction been carried out. As a result of the projects, extraction Pastoral Industry The pastoral industry is by fa r the from the Basin by pastoral bores is dominant water user in the Basin. estimated to have been reduced by 14% from 580,000 to 500,000 ML/a. Waste .Before the commencement of recent from pastoral bores has been reduced infrastructure renewal projects in the pastoral industry, extraction was from 380,000 ML/a to 300,000 ML/a. 580 ,000 ML/a. Current extraction by The cost to save each ML/a of flow varies between jurisdictions. In Sou th pastoral bores is estimated to be Australia the low average cost reflects 500,000 ML/a. the large number of shallow, inexpen- Town Supply sive bore plugging jobs that have been The Basin supplies 66 towns-many carried out. In New South Wales the very small-with a reliable water cost per m egali tre saved is high. supply. Some towns are heavily reliant However, 220,000 hectares ofland have on artesian water, w hile others use it been secured with permanent water as a only for specific purposes or as a reserve. result of these works. Total use by towns across the Basin is Overall, the total cost per ML saved 20,000 ML/a. is $297 of which the public expenditure Petroleum per saved ML is $221. By comparison, Petroleum products are produced surface water storage schemes in this from the aquifers of the Basin m d from arid zone are likely to cost in the range underlying older basins. Water is also of $600 to $1,500 for each ML/a of extracted in the process of producing yield. petroleum. It is estimated that petroleum producers extract 20,000 ML/a of water Table 2 Water outflows from the from the Basin. Great Artesian Basin in ML/ a Natural Vertical leakage Mound springs Total

400,000 (?) 47,000 447,000

Human extraction

Feedlots and other industrial

500,000 20,000 20,000 12,000 11,000 6,000

Total

569,000

Pastoral bores Towns Oil/gas fields Irrigation, feedlots Mining

Irrigation Generally the water of the Basin is too rich in sodium to successfully irrigate the overlying soils and could cause the soil to lose its permeability and form a hard crust. However, in some areas the water chemistry and soil are suitable for irrigation. In the north of the Basin 4,000 ML/a has been allocated for irrigation. There is significant irrigation development in the recharge area on the south-east margin w here currently 8,000 ML/a is extracted. This could rise to 35,000 ML/a over the next few years if existing WATER JULY/AUGUST 1998

U,


WATER entitlements are fully developed. Investigation of the likely impacts of this potential development is continuing. T otal extraction for irrigatio n is curren tly 12,000 ML/a which may increase to 39,000 ML/a. other Uses On the eastern side of the Basin, particularly in the subartesian margin west of Toowoomba, 6,000 ML/a has been allocated for feedlot and o ther industrial purposes.

Mining Economic deposits of metallic minerals (predominantly copper, lead, zinc, gold and silver) exist in close proximity to the edges of the Great Artesian Basin, and underlying the Great Artesian Basin in much older Permian rocks. In recent years significant quantities of water have b ee n extracted to supply water to new mines established on the margins of the Basin. The single maj or user is Olympic Dam in the south-west of the Basin where current extraction is 5,500 ML/a. Extraction could rise to 15,000 ML/a by 2010.

Several of the n ew mmes (Cannington , O sborne and Ernest Henry) established on the north-west margin of the Basin obtai n supply from the Basin. T hese mines have projected lives of 20 to 30 years. H owever, mining could continue beyo nd that date. As a result of the application of new geophysical techniques, it is possible that n ew ore bodies could be located under the thin sediments on the margin of the Basin. Total extraction from the Basin in the north-west is 5,000 M L/a. In the south-east 300 ML/a is u sed by opal mines at Lightning Ridge. However, possible future mines on th e southern margin could have a demand as high as 35,000 ML/a. The Basin might be seen as a possible source of at least some of this water requirement. Total extraction by mines is currently 11,000 ML/a.

Summary of Water Extraction Total extraction from the Basin is set out in Table 2. The extraction for pastoral purposes may reduce as the programs of infras tructure re newal

OlfJOW<TCAEEJ(

i~t[1::) l~~>~f

ISBANE

¡Figure 3 Distribution of artesian bores

12

WATER JULY/ AUGUST 1998

progress, but mining and irrigatio n may deman d increased allocations.

Impacts of Water Extraction Water Pressure As noted previously, water pressures have fallen as a result of water extraction. M ore than on e third of the 4,700 bores that have been constructed have ceased to flow because of the fall in pressure. Environment Artesian springs have important environmental valu es. Many mound springs, particularly in South Australia, contain species of plan ts and animals that have undergone gene tic differentiatio n and speciation as a result of the isolation of each group of springs by large tracts of arid land (Ponder, 1986; Ponder e t al. , 1989). Some mo und springs provide valuable scientific information about c hanges in local plant communities and water flow characteristics over approximately 2,000 years through pollen and radiation studies (Boyd , 1994). Mound springs provide, in an otherw ise arid location, the e nvironment necessary to support aquatic invertebrates with total dependence on water throughout their life cycles su ch as molluscs and crustaceans (Ponde r, 1994). In additi on, they are a valuable wa ter source for some larger native vertebrate animal species (Kinhill, 1997). Springs are an important aspect o f Aborigi nal culture. Although there do not appear to be any mound springs that were maj or ritual centres, they played an important p art 111 trad itional economics as they were a reliable source of water in times of drought when the waterholes failed . Springs also support tourism , w hich in turn supp orts c urre nt ~con omic system s. Spring flo w has been reduced as a result of water extraction. For example, the Elizabe th Springs near Boulia on the w estern margin flowed at 32 litres per second in 1896, covered an area of about 120 hectares, and ran water 32 kilometres down a nearby creek. As a result of water extraction by bores the flow rate fell to 5 litres per second by 1914 (Ogilvie, 1954). Even after the substantial loss of flow that has occurred , spring flow is still 47,000 ML/a and remains an important natural feature of th e Basin. Land Bore drains can cause environmen tal degradation. During rain they collect overland flow whic h grows to exceed drain capacity and eventually breaks out of the drains to cause erosion. Saline


WATER swamps form at the tail end of bore drains, while grazing stock concentrate around drains to result in overgrazing. Bore drains are also a major factor in the spread of woody weeds such as Prickly Acacia and provide a habitat for feral animals.

Biodiversity The introduction of permanent artificial water sources to supply stock has changed the mix of native species. Some have flourished under the pressure of grazing supported by artificial water sources. Others have suffered as a result of competition (Landsberg et al., 1997). Water distribution by piping to tank and trough has less impact on natural species distribution than bore drains, as piped systems can be managed (e.g. water can be turned off when paddocks are destocked during drought). Conclusions The Great Artesian Basin is a multilayered artesian flow system. Current extraction from the Basin exceeds the rate of recharge. As a result, artesian pressures continue to decline in many areas. Half of the flow from bores in the Basin is wasted as a result of uncontrollable pastoral bores and bore drains. The Basin will eventually stabilise at lower discharge rates than the current rate of extraction. If net extraction is deliberately reduced by conservation measures, artesian pressures will be stabilised at higher levels. In the absence of conservation measures, artesian pressures will stabilise at lower levels, resulting in increased cost to obtain supplies and further impact on the environment. References Boyd WE, 1994, Quaternary Pollen Analysis in the Arid Zone in Australia: Further Results from Dalhousie Springs, Central Australia, Australian Geographic Studies 32(2):274-280. Habennehl M A, 1980, The Great Artesian Basin, Australia: BMR Journal of Australian Geology & Geophysics, 5, 9-38. Habcm1ehl M A, 1982, Springs in the Great Artesian Basin: Their Origin and Nature, Bureau of Mineral Resources, Geology and Geophysics: Report 235, Australian Government Publishing Service. Habennehl MA, 1996, Groundwater Movement and Hydrochemistry of the Great Artesian Basin, Australia: Mesozoic Geology of the Eastern Australia Plate Conference, Brisbane, 23-26 September

1996. Habermehl M A and Lau J E, 1997, Hydrogeology of the Great Artesian Basin, Australia (Map at Scale 1:2,500,000): Australian Geological Survey Organisation, Canberra. Kinhill Engineers, 1997, Olympic Dam Expansion Project Environmental Impact

Statement. LandsbergJ,James CD, Morton SR, Hobbs T ], Stol J, Drew A and Tongway H, 1997, The Effects of Artificial Sources of Water on Rangeland Biodiversity, Environment Australia/CSIRO Wildlife and Ecology, Canberra. Ogilvie C, 1954, The Hydrology of the Queensland Portion of the Great Australian Artesian Basin: Appendix Hin Artesian Water Supplies in Queensland, Department of the Coordinator General of Public Works, Queensland Parliamentary Paper A56-1955, pp.21-61. Ponder W F, 1986, Mound Springs of the Great Artesian Basin: in De Dekker P and Williams W D (Eds.), Limnology in Australia: Melbourne CSIRO. Ponder W F, Hershlcr R, Jenkins B, 1989, An Endemic Radiation of Hydrobid Snails from Artesian Springs in Northern South Australia: Their Taxonomy, Physiology, Distribution and Anatomy: Malacologia 31(1), pp.1-140. Ponder W F, (1994) Australian Freshwater Mollusca: Conservation Priorities and Indicator Species, Memoirs of the Queensland Museum 36(1), pp.191-196. Queensland Government, 1954, Artesian Water Supplies in Queensland: Report Following First Interim Report (1945) of Committee Appointed by the Queensland Government to Investigate Certain Aspects Relating to the Great Artesian Basin (Queensland portion) With Particular Reference to the Problem of Diminishing Supply: Depart-

ment of the Coordinator General of Public Works Queensland, Parliamentary Paper A56-1955. Sibenaler X P, 1996, The Great Artesian Basin: A 25 Year Water Use Scenario: MESA Journal, 2:18-19. Torgersen T, Habermehl MA, Phillips FM, Elmore D, Kubik P, Jones B G, Hemmick T, and Gove H E, 1991, Chlorine 36 Dating of Very Old Groundwater: Further Studies in the Great Artesian Basin, Australia, Water Resources Research, 27(12), 3201-3213. (December 1991). WMC (Olympic Dam Corporation), 1996, Environmental Management Programme Annual Report, 1.3.89-28.2.90 Olympic Dam, South Australia.

Authors Both authors are with the Queensland Department of Natural Resources, GPO PO Box 2454, Brisbane Qld 4001. Randall Cox is a Senior Project Officer, Hydrogeologist and member of the Great Artesian Basin Consultative Council (GABCC). As chair of the Great Artesian Basin Technical Working Group he is currently directing the compilation of a resource study of the Basin for the GABCC. Alastair Barron is a Hydrogeologist who has played a key role in the compilation of the GAB resource study.

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13


WATER

.

EA (Bob) Swinton

Riverland Water Plants Come On-Line A country pub out in the never-never, a chain ferry across a wide grey-green river, then twelve kilometres of corrugated dirt road over rolling salt-bush following a lone power line. Suddenly, the road drops into a gully; there's a glimpse ofa pipeline and an old red-brick pumping station. Into view comes a brand new high-tech water treatment plant in the middle ofnowhere. This was my introduction to the second plant that Riverland Water has b uilt and commissioned, at Swan Reach, some 150 km from Adelaide (see Figure 1). My host, Riverland Water's Comm unity Relations Manager, Stan Boath and I knock for en try in to the windowless blo ckhouse and are confronted with computers, laptops, a wall full of o nline analytical instrumen ts, a small laboratory for calib ration p urposes, and four co111111issioning operators, bu sily engaged in ramping up one of the two trains to test its limits. T he plant has been supplying up to 90 M L/d of clean treated water since J anuary 1998 to the Barossa Valley, the Yorke Peninsula and the 50 townships o n the route. H aving been supplied wi th 'grey-green' raw M urray water 14

WATER JULY/AUGUST 1998

since the pipeline was built in the 1950s, the Swan Reach customers are overjoyed. The fasci nating aspect is that the fi rst spade-full of rocky soil was dug out on the site in September 1996. In a mere 16 months the foundations have been

laid, the concrete pou red, th; internals assembled, the plant w ired for both power an d au tomatic control, and co111111issioning completed . The plant is a conventional system: alum and p oly- DAD MAC coagulation (with provision for PAC dosing when

/ ,Im p.1rched. The temperature OLltside is ,1 wi11dr .J /° C ,1nd the Patrol 11·c ha,·c been dri,·ing has an air conditioner stretched beyond its limits. I ask for a glass ofw,1tcr and .im served the latest prodL1ct. It is perfixtlr clear (0.2 NTU). cool (ollt of the fridge) wd unexpectedly as tasty J., mr own f1murite, the water harvested from Melbourne\ pristine forest c.1tchmc11ts. No wonder the ct1stomcrs ;1rc pleased.

I go outside and look doll'n the hill at the wide expanse ofgrcr-grccn river flowing slow!;-. so s!Oll'I)", .is it contim11:s its 2.500 km course from the Snowy mountaim. through the irrig.ition areas of Ne11 South Wales. Victoria and the Soll[h A!l.ltr,dian Riwrl.rnd. and eventually (if there is enough left) to the sea .it Gooln·ah. 1 knmv foll ,,,,·ell that the trc,wncnt is only conventional technology, but it is still something to wonder at.


WATER 1 9

9 7

1 9

~

Rivertand

Water

Waikerie

:i

Barmera

: I

Berri

I

i I

I

: .

Figure 1 Areas to be served by the ten Riverland treatment pla nts

necessary), polyacrylamide-assisted flocculation, multiple tube settlers, and a fi nal dual-layer filter, which is backwashed by an air-water scour system patented by North West Water. W here the n ew plan t is at the forefront of modern tech nology, at a w o rldw ide 'cutting edge,' is in the control system . I mentioned a blockhouse for the control room. T here are no windows, only a few solid skylights, and a steel door, all design ed to be vandal- proof. The reason ? Beca use th e plant is designed to be con trolled from eithe r o f two controllers in the distant towns of Berri or Murray Bridge. The compu ter screens are linked to similar screens in Adelaide, in the offices of Riverland Water, N orth West Water Australia (the operators and owners) and also in the office of the South Australian W ater Corp oratio n (the people who sign the cheques) . T here is even a test screen in the offices of GEI Automation. This is the Adelaide company w hich has devised the C ITE C T SCADA system and , m ore significa ntly, the link which allows instantaneous access by 'pointand- click' to any part of the syste m , whether the readings of th e ins truments, the flowmeters, or the MIMIC boa rd which enables any of the hu ndreds of plant components to be adj usted or identifies a n eed for maintenance. Whereas remo te control is already well established worldwide, the key w ord here is 'instantaneous.' W h at is different about this system is that it instantaneously accesses the network through the Ethernet package, rather than slowly and clumsily accessing each elem ent of the SCADA system . GEI uses conventio nal hardware, m o stly Allen - Bradley PLCs and controllers manufa ct ured by Rockwell Inc. Indeed , w hen a posse of Allen-Bradley e ng- ineers visited GEI to see th e system , their j aw s dropped when they saw the speed of response (see page 17 fo r more details) .

I I

I

Murray Bridge Loxton

9

,I

Tailem Bend Renmark

1 9 9

i l:

Sw an Reach

Mannum

9 8

: I:

Summit Storage

i.

I

Figure 2 Riverla nd Water const ruct ion program

GE I Automation is a small Adelaide company w hich commenced ope ration s by installing automation for the high- tech South Australian wine industry, t he n moved from wining to mining, w h ere it subcontrac ted to Baulderstone Hornibrook Enginee rs for the au tomation ofBH P 's Iron Duke mine. T he company then w idened its field to the dairy industry, the H olde n car manufacturing plant, some work for the Sou th Australian Engineering and W ater Supply D epartment for the Hope Valley and other plants, before contracting to develop the more sophisticated system for the Riverland plants.

at th e top of the M urray BridgeO nkaparinga pipeline, is rated at 70 ML/d. This plant was commenced in September 1996 , as soon ~s the contract was signed, and deliverea treated water to the Adelaide Hills area in N ovem be r 1997-a total of 14 mo n ths. The large r plant at Swan R each (90 ML/d) was built at the same time and commissioned o nly a couple of months late r. T he speed with which these two plants were built is a result o f the company's decision to e mploy a standardised syste m , replicated in appropriate sizes, for all the plants, and

An adv;111t.1gc of the remote control is that only one ope1~1tor is required. on call for 2 4 hours a day via a modem and lapcop. yet not restricted to office or home. For example, the plant oper;itor at the McArthur plant in New South Wales is a keen surfcr. Even though that plant is a stand-alone one with a SCADA system with nothing like the response speed ofthe GEi system, on a good day he wraps his beeper in pfastic, swfE it inside his wetsuit and goes surfing.

Operator Steve Prophet checks laboratory data

l[ anything requires attention at the plant the CITECT system p.1gcs his beeper. he cat1;J1c~ the next wave in. strolls up to his wagon, connects the modem to his laptop. and adjusts the plant from there. H e might even be able to catch a few more waves before the d.1y is finished.

Such a sys tem is esse n tial fo r Riverland W ater. T he company, partowned by North W est Water Australia, has a contract from South Australian W ater to build, own and operate ten plants of varying size to provide treated water to the pipelines servicing the Adelaide Hills, the Barossa Valley and the Yorke Peninsula, as well as the townships alon g the Murray River. Drawing on North W est's experien ce in Yan Y ean in Victoria and MacArthur in N ew South Wales, the decision was made for full remote control, with master con trollers fo r all ten plants situated at Berri an d M urray Bridge. The first plant, at Summit Storage,

it is anticipated that the construction p rogram outlined in Figure 2 w ill be maintained. (Ch eap er, and fas ter , ' by the dozen.') It is noteworthy that th e C ITECT system continually m onitors the performance of the plants, from th e trend lines fo r bo th quantity and quality. Riverland W ater' s co mpute r t he n calculates the appropriate invoices to South Australian Water. T he system is also co nnected to South A ustralian W ater's computer, w hich also monitors performance, and if necessary, check s w hethe r any relevant penalties have been applied. (See background to South Australian W ater contracts on page 16.) WATER JU LY/ AUGUST 1 998

15


WATER

South Australia has limited water resources, and apart from the groundwater resources of the south-east and in the Eyre Peninsula, the major population relies on catchments in the Adelaide Hills, suppleme nted by around 50% from the lower reaches of the River Murray. Hundreds of kilometres of pipelines built by the South Australian Engineering and Water Supply D epartment in the 1950s snake over the ranges from the river to reservoirs supplying the city of Adelaide and beyond. Until the 1970s the cocktail of water drawn from inhabited catchments plus the turbid and sometimes slightly saline wate r from the river were supplied untreated except for chlorination and chloramination. As a result, rainwater collection for domestic consumption has become a face t of South Australian living which is only slowly fadi ng away. In the 1970s a program of building water treatment plants for the city commenced. By 1993 six plants were in operation. At that time a complete reorganisati on of the water industry began, with the result that the Engineering and Water Supply Department was closed down and South Australian Water set up as a government manage-

ment co rporation with most of its engineering functions contracted out to private industry. An unusual proviso was that the winning tenderers should establish a South Australian-based industry with the potential to generate export income. The co ntract for operations and maintenance for the city su pplies (including the wastewater system) was won by United Water, a consortium of CGE (France), T hames Water (UK) and Kinhill Engineers (now owned by US company, Brown and Root). Beginning in 1995-6 and extending until 2011, the contract contains an obligation on the successful consortium to generate $630 million in export business. At the same time, the necessity for improvement of the subsidiary water supplies to the rural sector was well unde rstood, and it was decided to bundle the rural supplies into a single contract to generate a size sufficient to attract world-class bidders. This contract was won by Riverland Water, a consortium of North West Water Australia (itself a subsidiary of the UK company, North West Water which, having added power supply to its portfolio, has become United Utilities), plus AMP as a financier, and Bechtel as

engineer. National Australia Bank has joined in as a part financier (see the company structure in Figure 3). North West Water Australia provided the basic design, Baulderstone Hornibrook Engineering are the constructors, and they have employed CMPS&F for detail design. North West Water Australia "is responsible for construction and continued operation of the plants for fees based on quantity and quality. The company also has an obligation to generate business exported from South Australia totalling more than $230 million in the first ten years. The term of the contract is 25 years from the end of construction, w hich began in September 1996 and is estimated to take three yea rs to complete. The capital cost of the plants themselves is estimated at $115 million. Riverland Water will supply treated water to 90 communities from ten plants of varying size to an estimated population of 150,000. The city plants supply one million, w hilst the Morgan plant, built in 1986, supplies• ll0,000. Thus treated water will eventually be supplied to 1.26 m illion out of a total population of 1.4 million. This will include all communities with a population of more than 1,000.

r

SA WATER

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RIVERLAND WATER AMP

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Figure 3 Riverland Water structure

16

WATER JULY/ AUGUST 1998


WAYE R

GEi Automation has been subcontracted by Baulderstone Hornibrook Engineering (BHE) to provide the instrumentation and control systems for ten Riverland Water filtration plants that are being built to service South Australian Water's rural customers. Whatever their size, these plants will be con trolled to run automatically at a throughput that is determined by water demand and all process parameters will automatically shift to maintain water quality at whatever output is demanded. Each p lant is controlled by twin Allen-Bradley PLC5/80E programmable logic controllers, configured with one PLC in ' hot standby' mode, allow-

ing seamless changeover in the event of failure of the operating PLC. T hese interface with the electrical switchgear, process sensors and drives, allowing control of all discrete devices and closed-loop (PID) control of all analog process variables. The interface uses Allen-Bradley 'flex 1/0' designed to be located remotely from the processors, enabling cost-effective co ntrol of a distributed plant. The use of Allen-Bradley variable speed drives in the remote 1/ 0 configuration, controlled by a serial communication s link from the PLC, allows detailed performance on the drives to be accessed for data logging. For example,

(ÂĽl SUMMIT

Overview

PACTakl

information about large pumps such as run times and kilowatt hours consumed can be collected and used in the maintenance planning process. The C ITECT screen- based operator interface allows operators to oversee all aspects of the plant, adj ust set-points, manually operate plant items and obtain reports of plant operation and performance (see Figure 1). Operators can also control the plants via dial-in facilities, enabling plant control from a laptop PC at the operator's home. In addition, the plant will automatically page the operator if a serious alarm condition occurs wh ilst th e plant is unattended. These facilities can also be used for GEi Au tomation staff to conduct trouble- shooting or modifications from a remote location if required. The plants will all be tied tog ether in a network using high-quality Telstra data (ISDN) lines and Ethernet comm unications protocol, allowing control from two centres located at Berri and Murray Bridge and reporting to Riverland Water headquarters and SA Water offices in Adelaide. The data communications system carries plant performance and production statistics required for billing and allows operators at any plant to access the centralised maintenance management system .

Author David Steele is the Sales Manager/ Director of GEi Automation Pty Ltd, PO Box 369, Campbelltown, SA 5074 (email gei@camtech. net.au), a company specialising in electronic sensors and automatic controls. Figure 1 Overview screen of CITECT SCADA for Riverland Project

WATER JULY/AUGUST 1998

17


WAYE R

CRYPTOSPOR/0/UM AND WATER:

WHAT DO WE KNOW? B Robertson, M Sinclair, M Hellard, C Fairley Since 1990 there have been 27 published outbreaks worldwide . Of This paper is a review of the current state of knowledge of the impact of these, 12 were attributed to drinking Cryptosporidium on public health and water, with the number of affected the possibility of infection via water people varying between 36 and 1,731. supplies. The paper concludes that the (These figures exclude the Milwaukee incidence in Australia is low and that epidemic which affected 403,000 people.) Swimming pools accounted for objective studies are required. seven outbreaks, with eight to 2,070 people affected ; animals accounted for Introduction A dilemma facing most water fo ur farm outbreaks, with 14 to 47 authorities is what to do when their people affected; two person-to-person drinking water is found to contain outbreaks affected 23 people; one apple Cryptosporidium oocysts. This is not a cider outbreak affected 154 people and rare event since oocysts are found in one foodborne outbreak affected 50 most su rface water supplies at some people. An indication of the characteristics of time. Despite this, there have been no cryptosporidiosis can be obtained from cases of cryptosporidiosis attributed to drinking water in an Australian capital two sources: human volunteer studies city. This could either be because the and epidemics. Only two human volunteer studies small numbers of oocysts in drinking water do not cause human disease or have been undertaken. In the fi rst of because o ur system s for detecting these studies 29 healthy voluntee rs without evidence of previous infection human disease are poor. Cryptosporidium is a coccidian were fed between 30 and 1 million protozoan parasite first discovered by oocysts and closely observed. Of the Tyzzer in 1907 in the gastric glands of five volunteers fed 30 oocysts only one laboratory mice. 1 2 It was subsequently became infected (defined by oocyst noted to cause disease in a range of positive stools) but this person develanimal species, and gained prominence oped no symptoms. Of the remaining in the 1970s when the first human 24 fed between 100 and 1 million infections were diagnosed. 3 4 In 1982 oocysts, 17 became infected and 11 Cryptosporidium was found to cause became ill. Symptoms most commonly severe disease in patients with acquired experienced were diarrhoea (which immune deficiency syndrome (AIDS) lasted for an average of three days), and several years later the first outbreak abdominal pain and nausea. 13 was recorded in people with normally One year later 19 of the original fu nctioning immune systems. 5 Since volunteers were re- fed 500 oocysts. this time further outbreaks have After this rechallenge, only three volunoccurred. H owever, these probably teers were infected (again defined by represent only a very small fraction of all oocyst- positive stools), w hile seven cryptosporidial disease. developed symptoms without oocystshedding. This indicates that past Human Disease exposure may reduce oocysts being There are a number of different shed but may not prevent the developspecies of Cryptosporidium, but only ment of future illness. 14 The Milwaukee epidemic provided C. parvum causes the hu man disease, cryptosporidiosis, which is acquired by further information from a random the ingestion of oocysts from either telephone survey of the Milwaukee human or m ammalian faeces. Modes of Water Works service area. Of 482 transmission include contaminated respondents, 20 1 had clinical cryptodrinking water or beverages, contami- sporidiosis with watery diarrhoea which na ted food, contact with infected lasted on average 4.5 days. The average p eople or animals, exposure to contam- maximal number of stools passed p er inated swimming pools and other recre- day was 7.7. Of the 201, 168 had ational water activities. 6 7 8 9 10 11 12 abdominal cramps, 72 had fever and 37

Abstract

18

WATER JULY/AUGUST 1998

vomiting. No deaths were reforted in those with normal immunity. In Australia in the year 1996 no cases of death were attributed to any protozoan infection including cryptosporidiosis. Gastroenteritis (according to the World.H ealth Organisation's classification range 001-009) did account for ~2 deaths, of which the most common single cause was viral gastroenteritis which accounted for 36 (unpublished causes of death data, Australian Bureau of Statistics) . In those with AIDS, cryptosporidiosis is a chronic, severe and disabling condition. It is associated with prolonged diarrhoea for a median of 60 days, abdominal pain in at least 80%, a median weight loss of 13.6 kg, nausea and vomiting. Diarrhoea is frequen tly severe and has been reported to be as high as 25 litres per day. Moreover, cryptosporidiosis significantly shortens the lifespan of these individuals.7 15

Incidence of Sporadic Cryptosporldlosls An estimate of the amount of cryptosporidiosis can be obtained from the rate of gastroenteritis from all causes and the proportion of faecal samples from patients with diarrhoea that have C. parvum. The rate of gastroenteritis in the community has been estimated at about 0.7 episodes per person per year. 16 A survey of fo ur private Melbourne laboratories fou nd that C. parvum was detected in 1-2% of faecal specimens. 16 These estimates are broadly supported by preliminary fi ndings from the Water Quality Study currently under way in Melbourne. 17 The rate of gastroenteritis is at least 0.5 episodes p er person per year amongst study participants. Of298 faecal specimens collected from those with gastroenteritis, 35 had pathogens of which five (1. 7%) were C. parvum. It must be appreciated that estimates derived by these calculations may both substantially over- or under- estimate the true incidence of disease. Notwithstanding these concerns, however, broad estimates can be put into a lifetime perspective. If an average


person lived for 100 years, he or she could expect 50 cases of gastroenteritis over the course of their lifetime, of which perhaps one would be caused by

C.parvum. Alternatively, in Melbourne, a city of 3 million people, there would be about 1.5 million cases of gastroenteritis from all causes each year, of which about 25,000 may be due to C. parvum.

Drinking Water and Cryptosporidiosis Highly publicised outbreaks give the

impression that drinking water is a common source of this infection. Although low numbers of Cryptosporidium oocysts are commonly detected in many surface water supplies, cryptosporidiosis has not been shown to be caused by drinking water in an Australian capital city. For an individual to become ill they need to ingest adequate numbers of viable C. parvum oocysts. The lowest dose in volunteer studies that has caused symptoms has been 100

oocysts, 13 although in risk assessment models it is assumed that even one oocyst may cause infection. Concentrations of 100 oocysts in a single glass of drinking water are rarely found, and even if they are, many may be other species of Cryptosporidium or non-viable. A recent study using polymerase chain

reaction

(PCR)

oped country is currently under way in New Zealand. The Water Services Association of Australia through the Cooperative Research Centre for Water Quality and Treatment is about to undertake a similar study of cryptosporidiosis in Adelaide and Melbourne. The advantage of using these two cities is that water supplies from different ends of the water quality spectrum can be studied and compared. Melbourne has high quality source water from protected catchments which undergoes only light chlorination, while Adelaide

has relatively poor quality source water from the Murray River which undergoes extensive treatment and filtration.

Conclusion Knowing the health implications of a positive water sample for C. parvum is difficult given our current level of knowledge. Volunteer studies can provide some information but are highly contrived human experiments, and outbreaks are rare and probably involve very unusual circumstances. Considerable caution is required when applying the findings of these studies to

sporadic cryptosporidiosis. Consequently, the temptation to blame a particular source for sporadic cryptosporidiosis should be resisted until additional studies objectively assess its routes of transmission.

technology

suggests that viable C. parvum oocysts may only be found in a minority of Cryptosporidium-positive water samples. 18 The alternative explanation is that drinking water does cause sporadic cryptosporidiosis but that it may be too difficult to detect in the community. This hypothesis is supported by a study

that correlated turbidity levels and increased rates of gastroenteritis in children for 15 months before the

Milwaukee epidemic was discovered. This suggests that drinking water may have been causing gastroenteritis for months before the Milwaukee epidemic was actually recognised. 19 A case-control study is the only effective and practical method of assessing if drinking water is a risk factor for sporadic cryptosporidiosis. Sporadic disease, however, has not been assessed using this type of epidemiological study

design, but it has been successfully used during various epidemics of cryptosporidiosis. 7 10 20 A case-control study simply compares the characteristics of cases who have the disease with controls who don't. If drinking water is a risk factor for cryptosporidiosis, then cases should be found to drink more water than controls. The first case control study to look at sporadic cryptosporidiosis in a devel-

References 1. Tyzzer E E. A Sporozoon Found in the Peptic Glands of the Common Mouse. Proceedings of the Society for Experimental Biology and Medicine 1907, 5: 12-13. 2. Tyzzer E . An Extracellular Coccidium, Cryptosporidium muris (gen. ct sp. nov.) of the Gastric Glands of the Common Mouse.] Med Res 1910, 23: 487-509. 3. Nime FA, BurekJ D, Page D L, Holscher MA, Yardley J H. Acute Enterocolitis in a Human Being Infected with Protozoan Cryptosporidium. Gastrocnterol 1976, 70(4): 592-98. 4. Meisel J L, Perera D R, Mcligro C, Rubin C E. Overwhelming Watery Diarrhea Associated with a Cryptosporidium in an Immunosuppressed Patient. Gastroentcrol 1976, 70(6): 1156-60. 5. Current WL, Reese NC, Ernst JV, Bailey WS, Heyman MB, Weinstein WM. Human Cryptosporidiosis in Immunocopetent and Immunodeficient Person. N Engl J Med 1983, 308(May 26): 1252-57. 6. MacKenzie W, Hoxie N, Proctor Mea. A Massive Outbreak in Milwaukee of Cryptosporidium Infection Transmitted through the Public Water Supply. New Eng] Med 1994, 331(3): 161-167. 7. Goldstein S T,Juranck DD, Ravenholt 0, Hightower AW, Martin D G, MesnikJ L ct al. Cryptosporidiosis: An Outbreak Associated with Drinking Water Despite State-of-the-Art Water Treatment. Ann Intern Med.1996, 124(5): 459-68. 8. Heath T C, Conaty S J, Capon A G.

Delayed Notification of a Large Outbreak of Diarrhoeal Illness in a Child Care Centre. Med J Aust 1995, 163(2 October): 388-9. 9. MolbakK, Aaby P, HojlyingN, da Silva A P J. Risk Factors for Cryptosporidium Diarrhea in Early Childhood: A CaseControl Study from Guinea-Bissau, West Africa. American Journal of Epidemiology 1994, 136(7): 734-40. 10. Lemmon J M, McAnulty J, BawdenSmith J. Outbreak of Cryptosporidiosis Linked to an Indoor Swimming Pool. M]A 1996, 165(2/16 Dec). 11. Bell A, Guasparini R, Meeds D, Mathias R G, Farley J D. A Swimming Poolassociated Outbreak of Cryptosporidiosis in British Columbia. Can J Pub Hlth 1993, 84(5): 334-7. 12. Millard P, Gensheimer K, Addiss D, Sosin D M, Beckett G A, HouckJankoski A et al. An Outbreak ofCryptosporidiosis from Fresh-pressed Apple Cider.JAMA 1994, 272: 1592-1596. 13. DuPont H L, Chappell CL, Sterling CR, Okhuysen PC, Rose] B,Jakubowski W. The Infectivity of Cryptosporidium parvum in Healthy Volunteers. N Eng] Med 1995, 332(13): 855-59. 14. Cryptosporidium Volunteer Studies: What Have We Learned: Where Arc We Going? International Symposium on Waterborne Cryptosporidium. 1997 March 2-5; Newport Beach, California. 15. Mannheimer S B, Soave R. Protozoa! Infections in Patients with AIDS. Cryptosporidiosis, Isosporiasis, Cyclosporiasis and Microsporidiosis. Infectious Disease Clinics of North America 1994, 8(2): 483-498. 16. Hellard ME, Fairley CK. Gastroenteritis in Australia: Who, What, Where, and How Much? Aust NZ ] Med 1997, 27(2): 147-9. 17. Hellard ME, Sinclair MI, Ranmuthugala G, Pilotto LS, Padiglione A, Robertson B E et al. Beyond Coliforms: Measuring Human Health. Water 1997, 24(5): 26-8. 18. Kaucner C, Stinear T. Sensitive and Rapid Dection of Viable Gi.1rdi.1 and Cryptosporidium parvum in Large Volume Water Samples Using Wound Fibreglass Cartridge Filters and Reverse Transcription PCR. Appl Environ Microbial (in press). 19. Morris RD, Naumova EN, Levin R, Munasinghe R L. Temporal Variation in Drinking Water Turbidity and Diagnosed Gastroenteritis in Milwaukee. Am] Pub Hlth 1996, 86(2):237-39. 20. Morgan D, Allaby M, Crook S, Casemorc D, Healing T D, Soltanpoor N et al. Waterborne Cryptosporidiosis Associated with a Borehole Supply. CDR Review 1995, 5(7):R93-R99. 0

Authors Dr Brent Robertson is a General Practitioner and PhD student, Dr Martha Sinclair is a Senior Research Fellow, Dr Margaret Hellard is an

infectious diseases physician and PhD student, and Associate Professor Christopher Fairley is Head of the

Infectious Disease Epidemiology Unit, Monash

Medical

School,

Alfred

Hospital, Prahran 3181, a partner in the CRC for Water Quality and Treatment. WATER JULY/AUGUST 1998

19


WATER

CRYPTOSPORIDIOSIS FROM

PUBLIC SWIMMING POOLS D Lightbody

Reports of cryptosporidiosis have b een released to the press in a number of States to warn the public that hygiene practices in public swimming pools sh ould be observed. As reported in the April issue of Crosscurrent, the newsletter of AWWA, some 300 cases of cryptosporidio si s were reported in Q ueensland since December, many associated wit h swimming at various aquatic centres. In New South Wales, fo r the period December 1997 to t he beginning of March 1998, 461 cases of cryptosporidiosis were reported , many times higher than in l 996, the first year that the disease was defined as a reportable illness. New South Wales Heal th D epartment Edipemiologist Dr J eremy McAnulty said there had also been an outbreak in the ACT. A number of p ublic swimming pools closed for cleaning and disinfection, even though traces of the parasite were fo und in only a sm all number of pools. In Victoria, th e Department of Human Services was alerted by a study conducted by the Cooperative Research Centre (CRC) fo r Water Quality and Treatment (see Robertson et al. on page 18). Nine cases of cryptospori diosis were originally notified to th e Department. Seven of those person s (four family groups) reported swimming at a pa rticular aqu atic centre b efo re the illness. As a precautionary m easure that particular cen tre closed until water testing revealed t hat no organisms were present. A total of58 cases of cryptosporidiosis were reported during the period 1 March-14 April as a result of an active surveillance progam initiated by the D epartment of Human Services Victoria following n ews of the above notification. Another major M elbourne aquatic centre not identified by the CRC study was found to h ave nine cases asso ciated wi th it. Following shock-chlorination at 14 ppm for 12 hours, testing continued to indicate the 20

WATER JULY/ AUGUST 1998

presence of orga111 sms in the fi lter backwash and the pool was closed for a week to enable further treatment. At least eight other pools have conducted overnight shockchlorination as a precautionary measure following notification of a causal link of two or more cases of cryptosporidiosis or w here pool operators have submitted posi tive samples for analysis. Routine testing of pool water in the absence of notified cases is not recomme nded . To conduct detection and confirn1ation of viability by polymerase chain reaction (PCR) and mjcroscopy costs around $450 per sample. To test all pools in one aquatic centre would cost $7,000 for one momentary snap in time. T he pool would require an extra 2,800 visitors to recoup this expenditure. Testing does not guarantee th e future safety of the water and does not verify the suitability of the treatment process. If the re are no adequa te controls for Cryptosporidium, there is no point in veri fying som ething that cannot be controlled by operational means. Literature suggests that chlorine dioxide treatment (CT 78 compared to chlorine CT 7200- 9600) may be the most effective m eans of sanitising pool water against Cryptosp oridium. However, chlorine (hypochlorous acid) is still required as a conj unctional treatment to oxidise ammonia present in pool water and minimise chlorite formation. Ozone, whilst effective, is depende nt on circulatio n flows and

c hambe r deten tion times. In most applications it would not be effective in reducing oocyst numbers within an acceptable time period (e.g. overnight) . T here are concerns that some oocysts trapped by filtration could break through the filter m edia instead ofbeing removed by backwashing. Treatment of th e media by heat or chemicals is recommended to prevent this occurrence following out-breaks. For preventative maintenance th e followi ng applies: Q. How often should filter treatm ent be done? A. How lo ng is your piece of string? One company h as proposed a quarterly treatm ent process for pools in Brisbane. Whether that type of program would have any effect probably will never be established-it appears only to be a ' feel good' measure. Persons w ho contract and probably spread cryptosporidiosis from poo r hygiene practices are usually of an age group that are al so pa rti cipating in swimming programs through school o r at the toddler stage. This may explain the link to swimming facilities. T he re is no t eno ugh evide nce at present to suggest that m os t o f th e affected co ntracted their infection s from swim ming, given the low attack rates and high patronage at the relevant pools. Public edu ca tion abou t pe rson al hygiene and self exclusion following illness rather than en gineering solutions are seen as the best way of minimising t he spread. Pools n eed to develop policies in relation to toddlers w ho are not toilet-trained (one option is requiring the use of pants that w ill contain wastes) and procedures to deal with faecal spills if they occur.

Author Derek Lightbody is the Environm ental H ealth Officer in the Victorian Department of Human Services. He is located at 17/120 Spencer Street, M elbourne Vic 3001 .


WATER

Ii

¡¡

.

PHOSPHORUS IN PUTS TO A RESERVOIR IN ORANGE, NSW M H Chowdhury, D Al Bakri Abstract This paper presents the methodology and fi ndi ngs of a proj ect undertaken to dete rmine the levels and pote n tial sources of phospho rus in the Suma Park catc hment i n Orange, New South Wales, so that appropriate managemen t strategies could be developed to control eu trophication and algal bloom fo rmatio n in the m ain reservo ir. Wa ter quality sampling and m easureme n ts were taken weekly from 12 sampling sites between 3 August 1995 and 31 J anuary 1996. T he catchment's streams and reservoi rs were fo und to be enriched w ith phosphorus. Regression analysis de m onst rated that strong relationships exist between total phosphorus (P) load, suspended sedimen t load and discharge. Evidence from this study and other recent studies suggests that background (native) sources derived from T ertiary basalt soils could be the p rimary contributor of P in the catchment waterways.

Key Words Eutrophication , algal blooms, phosph orus, ru noff, bank erosion, internal loading

Introduction Suma Park Reservoir, which is the main wate r supply for the City of Orange, has a history of nui sance growth of toxic blue-green algae. Levels of up to 70,000 cells/mL of cyanobacte ria (Anabaena and Microcystis) have been frequently recorded in the reservoir during su nuner and autu m n (Al Bakri and C howdhu ry, 1997a). Consequently, complaints from residents about obnoxious odour and taste in their drinking water were frequently reported during this period. Outbreaks of blue- green algae have also been recorded in the other catchment reservoir (Spring C reek), but with less intensity and freq uency.

The Orange C ity Council and the community are concerned about the environmen tal, health , economic and aesthe tic imp lications of the algal bloom s. Lack of relevant and reliable data has been the main impediment to developing an appropriate catchment management plan. To remedy this situation , a two-year study was commenced in March 1995 to assess water quality and investigate the ca uses and processes underlying the algal outbrea ks in Suma Park Reservoir (Al Bakri et al., 1995). The excessive availability of P in waterbodi es is co n sidered the most important cause of algal bloom formation in freshwate r systems as it is often the nu trie nt limiting growth (Perry and Vanderklein, 1996). T he purpose of this study was to determine the levels and potential sources of P in the catchment in order to establish a sound basis fo r the development of effective management strategies to con trol eutrophication and minim.ise algal blooms in the reservoirs.

Geography and Geology of the Catchment The Suma Park catchment is situated at the south-eastern edge of O range City and covers an area of 184 km2 (see Figure 1). Suma Park R eservoir has a storage capacity of 18,000 M L and the other two smalle r reservoirs in the catchment (Spring Creek and Gosling Creek), have a combined storage capacity of 5,350 ML. T he catchment is drained by the Summer Hill, Spri ng, Gosling and B randy C reeks. More than 76% of the catchment is covered by native or improved pasture. O the r landuses include c ropping ( 11. 9%), horticulture and viticulture (6.5%), timber and softwood plantations (3.3%), and waterbody and urban areas (1.5%) (Taylor, 1994). Tertiary basaltic rocks cover approximately 70% o f the catchment area (AGSO, 1995). According to Scott et al. (1994), the Tertiary basalt in th is area is rich in the phosphate mineral

apatite (Ca 5 (F,Cl)(PO 4 ) 3]. Simila r Tertiary basalt in other New Sou th Wales regio ns is also rich in mineral apatite with phosphate (P 20 5) values of up to 1% (Caitcheon et al. , 1995). O rdovician monzonite, mafic volcanics an d sedimentary rocks cover the remaining part of the catchment. Phosphorus is also high in most O rdovician igneous rocks at around 0.3 to 0.4 % P2O5 (Wyborn, 1994). Most of the alluvial deposits in the lower valley appear to be derived from basalt soil. It is expected that the soils derived from t he Tertiary basalt and Ordovician igneous rocks are phosphate-rich.

Materials and Methods Su rfacewater sa m ples and field measuremen ts from 12 sampling sites coveri ng the reservoirs and mai n tributaries o f the catchment were undertaken on a weekly basis between 3 August 1995 and 31 J anuary 1996. During storms additional samples were taken using rising stage samplers. Twenty- six sets of water samples and field measu rements from each of the three r.eservoirs and eigh t stream sites (Sites 1 to 11), as well as 11 samples and measurements from the control site (Site 12), were collected and tested (see Figure 1). T hree hundred su rfacewater samples were analysed to determine total phosphorus (TP) and suspended sediments. TP was determined from unfilte red water samples following the persulfate digestion method (H osomi and Sudo, 1986). D igested samples were the n analysed for TP following the ascorbic acid method (Method- 8048) described in H ACH (1992). This method is approved by th e USEP A (H ACH , 1992). For determining reactive phosphorus (RP), raw water samples were filtered before addition of the colorometric reagents, and the ascorbic acid method (Method- 8048) was the n followed . Suspended solids were estimated by following the meth od WATER JULY/AUGUST 1998

21


WATER APHA 2540-D (APHA, 1995). W ater samples were passed through a preweighed glass fibre filter. The filte r and residue were then dried at 100° C to a constant weight. The increase in weight of the filter represented the suspended solids. A quality assurance program was implemented to evaluate the variability of the testing procedures and the accuracy of test results. Duplicate samples of about 10% of the tested samples were analysed at the Orange City Council laboratory or at the laboratory of the Department of Crop Scien ces, The University of Sydney. In addition, 50 randomly selected duplicate samples were tested by NATAcertified commercial laboratories. Stream velocities were determined using a PYGMY current meter model OSS-PCI and stream discharge was estimated following the Area-Velocity method (Brassington, 1988). Stream velocities from three sampling sites (2, 3 and 4) were recorded and the instantaneous flows for all sampling episodes were determined from the rating tables (Chowdhury and Al Bakri, 1997). Flow and concentration data were used to calculate catchment loading by applying the load duration method, averaging

method, regression method and ratio estimator method described in Robinson and Hatfield (1 992). Annual flows for the three sites were extrapolated using the regression models established b etween the mean daily flows for sites 2, 3 and 4 and the mean daily flows data for February 1995 to January 1996 from station 412105 of the adjacent Belubula River catchment, Blayney (Al Bakri and Chowdhury, 1997a). Catchment stream flow and loading of TP and SS are presented as both annual and for the study period. The regression models developed for flow data and TP and SS load data for six months were used to extrapolate the annual loads of the catchment (Al Bakri and Chowdhury, 1997a). Rainfall during the study period is given in Figure 2.

Results Phosphorus Concentration The range of TP con centrati ons from 300 water samples analysed from all the 12 sampling sites was between 20 µ g/L and 590 µg/L. Overall mean and median values for the whole catchment were 80 ug/L and 60 µg/L, resp ec-

City of Orange

Waterbodies

C

Sampling sites: 1, 2, 3 ...

<

Flow direction

Figure 1 Sampling sites (1-12) at Suma Park Catchment

22

WATE R JULY/AUGUST 1998

tively. On a subcatchment basis, TP concentration was found to be highest in Summer Hil1 Creek (mean of 97 µ g/L and median of82 µ g/L) and lowest in the reservoirs, with mean and median values of 60 µ g/L and 50 µg/L, respectively. Mean and median ofTP concentration in Gosling Creek subcatchment were 83 µg/L and 58 µg/L, respectively. The median values did not show any systematic trend by site. However, Site 2, situated at the inletflow of Suma Park R eservoir, h as the highest mean and median values (108 µg/L and 80 µg/L, respectively) . In temporal terms the highest mean and median TP concentrations for al1 sites of the catchment were recorded in September, whereas the lowes t were observed during November, D ecember and Jan uary (see Figure 2). Rainfall pattern does not show any correlation with the temporal variability of TP concentration (see Figure 2). Comparing the study results with the Australian Water Quality Guidelines for Fresh and Marine Waters (ANZECC, 1992) and the rating system adopted by the NSW D ep arti;nent of Land and Water Conservation (Daly et al. , 1995; Daly et al. , 1996) , all watercourses and reservoirs in the ca tchment, including the control site (Site 12) , were characte rised by high P concentrations. Virtual1y all sampling sites have mean TP concentrations equal to or greater than 50 µg/L. TP co ncentratio ns recorded in this study are among the highest measu red in N ew South Wales and many exceed the limits recommended fo r controlling algal growth (Daly et al., 1995; Daly et al., 1996). Total phosphorus conce n tration from different depths of Suma Park R eservoir was measured in J anuary and February 1997. There was a significant variation in TP conce ntrati@n with depth. Significantly higher levels were found at the bottom layer than at the surface. T he range of TP concentrations at the deepest point of the reservoir (30 m) varied between 70 and 490 µg/L, w hereas the TP concentrations in the surface water ranged b etween 60 and 100 µ g/L (Al Bakri & Chowdhury, 1997a). R eactive phosphorus (RP) concentrations from 140 filtered water samples were found to range from a minimum value of 10 µ g/L (instrument detection limit) to a maximum of 90 µg/L with mean and median values of 30 µg/L. As in the case of TP concentration s, the highest RP mean and median (30 µg/ L) we re recorded from Summer Hill Creek subcatchment, and the lowest median and mean (20 µg/L) from the reservoirs. Du ring the months from November to January the catchment


WATER has relatively clear water, but RP concentrations w ere still relatively high and still above the levels recommended for the prevention of excessive algal growth. During this period, 45% to 64% ofTP was present as dissolved RP available for algal growth. When it is considered that as little as 10 µ g/L is sufficient for excess algal growth (CSIRO, 1994), it is not surprising that excess algal growth often occurs during low flow in the catchment, w hen high temperature, high light availability and degraded ecosystems are favou rable conditions for algal blooms. D uring January-February 1997, RP was determined from several profiles taken at different depths in Suma Park Reservoir. The results indicated that during thermal stratifica tion when the DO level is depleted (Al Bakri and Chowdhury 1997a), RP concentrations in the bottom water were significantly higher than those in the surface water. T he range of RP concentrations at the surface varied from 10-40 µg/L, whereas at the deepest point of the reservoir it varied between 70-110 µg/L. It is hard to come to a firm conclusio n on the basis of the small number of samples, but the trend of RP variation clearly indicates that the depletion of oxygen (anoxic condition) at the bottom of the reservoir enhances the release of soluble P fro m the bottom sediments. Total Phosphorus Load The total catchment TP load (load entering the Suma Park Rese rvoir th rough Site 2) was estimated to be 1,102 kg annually and 550 kg during the study period following the load duration method and up to 2,843 kg annually and 1,243 kg for the study time by applying the regression method. The load transported from Gosling Creek subcatchment (discharged through Site 4) contributed abou t 644 kg (58%) and 322 kg (59% ) to the total TP load, whereas Summer Hill Creek subcatchment con tributed 441 kg (40% ) and 212 kg (39%) to the total catchment load annually and during the study period, respectively. The balance of about 17 kg fo r both the year and the study period (2% ) were apparently contributed from the part of the catchment lying between the confluence of Gosling and Summer Hill Creeks (about 200 m downstream of Site 3) and Site 2. Annual export coefficient fo r t he whole catchment was estimated to be 0 .06 kg/ha/yr b u t, according to the regression method, it was 0.16 kg/ha/yr. In comparison with commonly used estimates shown in Tables I and II in C ullen and O'Loughlin (1982), P export from the catchment is consid-

ered high relative to P export from agricultural/grazing land in Australia.

P was the major component of the total P reaching the catchment waterways.

TP, Flow and Suspended Sediment Relationships Regression analysis did not show significant relationships between TP concentrations and either flow or suspended sediment (SS) data. However, TP load data showed a significant relationship with both stream flow and SS at Sites 2, 3 and 4 (see Figures 4 and 5). T he results of the study indicated that catchment loading was flowdependent and dominated by storm events (see Figures 6, 7 and 8). Approximately 70% of T P load and 73% of SS load entered Suma Park Reservoir wi th 70% of the flow that occurred in 10% of the study time. Based on evidence from this study and from other studies (Caitcheon et al., 1995; Heathwaite andJohnes, 1996), it can be argued that catchment loading was flow-depe ndent and dominated by the storm events and the particle- bound

Discussion The conventional view suggests that most of the P in Australian inland waterways comes from fertilised topsoil removed by agricultural runoff and/or from point sources suc h as sewage and industrial effiuents (Hart, 1996; Houldsworth, 199 5; Verhoeven, 1993). Several recent studies have argued that the current understanding of the sources and transport of P is not entirely valid for many Australian inland rivers (Donnelly et al. , 1996; Harris, 1995; Murray, 1996). These au tho rs and others (Murray, 1996; Martin, 1996, Caitcheon et al., 1995) have demonstrated that most of the P that reaches waterways comes in association with fi ne sediments derived from subsoil by gully and channel bank erosion.The study results do not show any systematic variation in P concentration/load in the catchment to indicate

350 300

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3.8 .95

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140 120 100 E E ~

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Sep-95

Oct-95

Nov-95

Dec-95

Jan-96

Month Figure 3 Mean total phosphorus co ncentratio ns at reservoirs and sub-catchments

WATER JULY/AUGUST 1998

23


WATER 4.5

3

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Figure 4 Total phosphorus load vers us flow: Sites 2, 3, 4

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Figure 5 Total phosp horus load versus suspended solid load : Sites 2, 3, 4

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Figure 6 Hydrogra phs: Sites 2, 3, 4; a, b, c-1995; d, e, f-during t he project, August 1995 to January 1996

that point sources or leaks from septic tanks have any tangible impact on the P input. Furth ermore, the re was no significant change in TP concentration upstream o r downstream of Lucknow, which is the main urban centre in the catchment. T his lack of significant variation in P concen tration with stream length confirms that input from point sources is not important in terms of total catchment load. The rates of superphosphate application in the catchment is considered low (Al Bakri and Chowdhury, 1997a) and most of the soil in the catchment is heavy and acidic and thus has a great capability to fix (immobilise) P fertilisers. Furthermore, the catchment is very stable with good perma nent vegetation and the surface soil erosion, 24

WATER JULY/AUGUST 1998

which is the mechanism by which P can be transported from fertilised topsoils to waterways, is insignificant (Chowdhury and Al Bakri, 1997). Taking into consideration the above information, one can conclude that P fe rtiliser carried by surface agricultural runoff is not a primary source of P in the wa terways of the catchment. Further support to this conclusion is the low TP concentration at Site 9. T his site is located at the end of B randy Creek which flows th rough the most in tensively farmed part of the catchment where ho rticulture, viticulture and cropping are the predominant landuses. Yet the mean TP concentration in this site was the lowest (60 ug/L) among all the stream sites, even lower than the control site.

The results of th is study, along with evidence from other studies (Caitcheon et al. , 1995; Murray, 1996; Donnelly et al. , 1996), suggest that the primary source of P in Suma Park Reservoir could be the background P in the soils derived from the Tertiary basalt and Ordovician volcanics. Since these rocks tend to contain a relatively high level of phosphate (up to 1%), th e soils derived fro m them are inherently rich in phosphate. This P which is intimately bou nd up with fine suspended sediment is believed to have been transported to the waterways from unfertilised subsoil by gully and stream bank erosion. The bioavailable P will be released into the water column from the particle- bound P in the suspended and bottom sedi-


WAT E R 140 200

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Figure 7 Tot al phosphorus load time series: a, b, c-1995 year; d, e, f-duri ng the project, August 1995 to January 1996

50000 - -- -- - - - - - ~

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Figure 8 Suspended solid load time series: a, b, c-1995 year; d, e, f-du ring the project, August 1995 to January 1996

ments, through internal loading, to facilitate the algal growth. O n the basis of the argume nt that th e majority of the P load in the reservoir is associated with sediment p articles, it is hypothesised that ' native' particle- P could be a m ajor source of the algalavailable compone nt of P. Additional research is requ ired to further substantiate how m uch bioavailable P is derived from native and other sources.

Conclusions Contrary to the conventional view, the results of this study indicate that background sources are more dominant t han agric ultural runoff and point sources in contributing to the P input in the waterbodies studied. Background 'native' P is believed to be as p rimarily derived from naturally phosphate- rich volcani c soils w hich cover most of the catchment. The internal loading m echa nism is believed to play an

important role in releasing bioavailable P from the particle-bound P in the bottom and suspended sedime nts. As the manipulation of flow conditions in th e catchment's creeks, particularly during low flow, is beyond control and some P reaches the waterways in association w ith sedimen t, management of the eutrophication and algal blooms should foc us on manipulating the P and fine sediment in the catchment. Tw o types of management strategies should b e targeted: short-term and long- term strategies. The short- term strategies should aim to have a rapid effect on water quality by treating the effects or symptoms of P enrichment by focusing on the waterbody within the Suma Park reservoir itself. The longterm strategies should aim to eliminate or reduce the causes of eu trophication by adopting catchment- based works to reduce sediment and P entering th e waterways.

Further details o n management strategies are outlined in Al Bakri and Chowdhury (1997a, 19976). It is recommended t hat othe r A ustralian catchments be investigated to furthe r test the hypothesis regarding the contribution of background so urces to P budgets in inland waterways. Additional studies are also needed to better understand the complex relationships between th e nutrients, soils and sediments in the streams and reservoirs. It is expected that the knowledge gained from these studies will contribute to a regional (Murray-Darling Basin) understanding of catchment behaviour and help define effective management options to decrease the frequency of algal blooms in Australian inland waterways.

Acknowledgements This proj ec t was funded by the National Landcare Program of Australia and received in-kind contribu tions WATER JULY/AUGUST 1998

25


WATER from the New South Wales D epartment of Land and Water Conservation and Orange City Council. We wish to thank all those people w ho contributed th roughou t the research work by providing technical support, comments, discussion of ideas, assistan ce in quality assurance laboratory results, reports and map production. We are especially grateful to Lee Bowling, Graham Brown, Andrew Sloan, W yane Beatty, Len Miller, Pe te r Martin and Rob Warner for their suggestions and technical assistance.

References AGSO (1995) Orange Regolith Landforms: 1: 100,000 Scale M ap , Australian Geological Survey O rganisation, Canberra. Al Bakri D , C howdhury M , R eddan B (1995) Assessment of Water Quality of O range Water Supply Catchment, The 3rd Annual Conference of Soil and Water, 12-15 September 1995, Sydney, p. 372. Al Bakri D, C howdhury M (1997a) Nutrients and Physico-chemical Characteristics of Orange Water Supply, report prepared for a workshop, Water Quality in Orange held on 16 May 1997 at Orange Agricultural ColJege, The Un iversity of Sydney, Orange, NSW, 1997, p. 58. Al Bakri D , Chowdhury M (19976) Nutrient Enrichment and Algal Blooms in Australian Inland Waterways: Towards Developing an Alternative Perspective . Conference Proceedings, Rural Australia: Toward 2000, Wagga Wagga, NSW, 2-4 July 1997, p. 18. ANZECC (1992) Australian W ater Quality Guidelin es for Fresh and M aline Water, Australian and New Zealand Environm ent and Conservation Council , Melbourne. APHA (1995) Standard M ethods For The Examination of W ater and Wastewater, 19th edn, American Public Health Association, W ashington, DC. Brassington R (1988) Field H ydrogeology, Geological Society of London Handbook Series, London. Caitcheon G, Donnelly T , W allbrink P (1995) Nutrient and Sediment Sources in Chaffey Reservoir Catchment, Australian J ournal of Soil and Water Conservation, 18 ( 2): 41-49. Chowdhury M , Al Bakri D (1997) Soil Erosion and Phosphoru s in Orange Water Supply, New South Wales. Conference Proceedings, The 5th Annual Soil and Water M anagem ent Conference, Stormwater and Soil Erosion 97, held on September9-12, 97, Brisbane, pp. 395-403. CS IRO (1994) Nutrients and Sediments Sources in Chaffey R eservoir Catchment, Division of Water R esources, CSIRO, Canberra. Cullen P, O 'Loughlin EM (1982) Non-point Sources of Pollution, in Prediction in Water Quality, eds E M O'Loughlin and P Cullen, Australian Academy of Science, Canberra. Daly H , Martin V, Bales M (1995) Window On Water, the State of W ater in NSW: 1993/1994, R eport No. TS94.141 of the

26

WATER JULY/AUGUST 1 998

Technical Services Division, Department of Land and Water Conservation, NSW. Daly H, Bowling L, Royal M, Deal, R, Mitrovic S (1996) Window On Water: the State of Water in NSW 1994/1995, Report No. TS96.030 of the Technical Services Unit, Department of Land and Water Conservation, NSW. Donnelly T H, OIJey J M, Murray A, Caitcheon G, Olive L , WalJbrink P (1996) Phosphorus Sources and Algal Blooms in Australian Catchments, in Proceedings of the National Conference on Downstream Effects of Land Use, Rockhampcon, 26-28 April 1995, eds H M Hunter, AG Eyles, and GE Rayrnent, Department of Natural Resou rces, Brisbane. HACH. W ater Analysis Handbook, 2nd edn, HACH company, Colorado, USA (1992). H arris G (1 995) Eutrophication: Are Australian Waters Different from those Overseas?, Water, Aust. Water and Wastewater Assoc., 22: 9-12. Hart B T (1996) Sediment Nutrient Uptake and Release: Progress T owards Predictive Models, N ational Workshop o n Sediment Nutrient Interaction, April 30, 1996, Albury. H eathwaite A L, J ohnes P J (1996) Contribution of Nitrogen Species and Phosphorus Fractions to Stream Water Quality in Agricultu ral Catchments, Hydrological Processes, 10: 971 -983. Hosomi M, Sudo R (1986) Simultaneous Determination of T otal Nitrogen and Total Phosphorus in Fresh Water Samples U sing Persulfate Digestion, Journal of Environment.11 Studies, 27: 267- 275. Houldsworth B (1995) Central and Northwest Regions Water Quality Program 1994/1995, A report on Nutrients and General Water Quali ty Monitoring, Report No. TS95.088 of the Water Quality Services Unit, D epartment of Land and Water Conservatio n , J une 1995, Parramatta, NSW. Martin P.M (1996) Slumping of Phosphorus Rich Bank Sediments as a Significant Source of Total Phosphorus Loading in the Wyong River, Central Coast, New South Wales. Murray A (1996) T ransport of Phosphorus in Turbid Australian Rivers: An Alternative H ypothesis, National Workshop on Sediment Nutrients Interaction, April 30, Albury. Perry J , Vanderklein E (1996) Water Quality: Managem en t of A Natural R esource, Blackwell Science, Cambridge, Mass. Robinson G, Hatfield E (1992) Application of Flow Duration Curves in Calculating Nutrient/Pollution Loadings. Poster paper presented at Enviconmencal Biom etrics Conference, Sydney, Australia, 14-15 D ecember 1992. Scott M, W arren A, Meakin S, Watkins S (1994) Orange Geology 1: 100,000 Basement Geology Series, Field Geology Conference, October 1994, Orange, NSW. Taylor S (1994) Macquarie River Catchment: Land Management Proposal for the Integrated Treatment and Prevention of Land Degradation, CALM, Bathurst. Verhoeven J (1993) [mplementation of the New South Wales Algal Management Strategy, Australian j ournal of Soil and Water Conservation, 6 (3): 30-34.

Wyborn D (1994) Regional Metamorphism in the Bathurst 1:250,000 Sheet Area, Field Geology Conference, October, 1994, Orange, NSW.

Authors Mosharef H Chowdhury is a PhD student at Orange Agricultural College, The University of Sydney, P O Box 883, NSW 2800, fax (02) 6360 5590 (e mail chowdhur@oac. usyd. edu. au) . Prior to this project, Mosharef acquired considerable experie nce in soil and irrigation water management, working with the National Agricultural R esearch Institute and Agricultural Extension Service ofBangladesh. Dr Dhla Al Bakrl is a Senior Lecturer in Environmental Management at Orange Agricultural College, The University of Sydn ey (email albakri@oac.usyd.edu.au). He has q tensive research and teaching . experience in sustainable lan d and water reso urce manage me n t gain ed from working in several institutions in the M iddle East, Europe and Australia.

BOOKS Controlling Sediment Movement and Nutrient Movement Within Catchments Cooperative Research Centre for Catchment Hydrology Industry Report $20 from A WWA Bookshop, fax (02) 9413 1047

Australia's rivers and streams are being degraded , and the water quality derived from most of our catchments is sh owing th e resul ts. Riparian vegetation is one method of controlling sediment runoff The proj ect presented in this booklet, which is part of a series en capsulating the key findi ngs of the fi rst five years of cooperative-research in catchmen t hydrology, focuses on the T arago catchment in Gippsland, Victoria. By a combinati on of sedime n t tracing and water quality monitoring th e project compares various techniqu es fo r controlling sediment and associated nu trient transfer to streams and reservoirs. The project also quantifies t he effects on land and timber resources of establishing buffer zones and assesses the impacts of w ildfire. Directions for future research are also covered . Other titles in the series are Development of An Improved Realtime Flood Fo recasting Model, U rban Stormwater Pollution and Stormwater Gross Pollu tants. E A (Bob) Swinton


WASTEWATER

DJ

-

DESIGN OF AERATED WASTEWATER

TREATMENT SYSTEMS FOR

ON-SITE WASTE DISPOSAL H B Dharmappa, M A Khalife

Abstract

Introduction

Key Words

Aerated wastewater treatment system , O n-site wastewater disposal systems On- site wastewater disposal systems have been adopted in small communi- A WTS aerated septic tank systems, on- in New South W ales have been develties for many years. There are several si te waste disposal, wastewater, country oped over the years in the following order: types of systems, such as pan service area, remote area, public health (PS), pump-out septic tank • pan service (POST), conventional septic • pump-ou t septic tank tank system (CSTS) and the (POST) more recently introdu ced )/influent . • conventional septic tank Irrigation chamber aerated was tewater treat/Air system (CSTS) ment sys tem (AWTS). • aerated wastewater treatExamination of the extenment system (AWTS) sive applicatio n of P S, AWTS is the most recent POST and CSTS over the development and these last few decades has highsystems have been available lighted several problems in the Australian market associated with these since 1983 (Bies, 1994). systems. They are provided for the Curre ntly, AWTS is treatme nt of wastewater being widely used throughExcess sludge pump out generated fro m single out Australia , particularly in dwellings to la rge commuunsewered suburban areas nities in rural areas where a Chlorine tablets dispenser where installation and reticulation system is not Sedimentation chamber maintenance are controlled available. A diagram o f a Plan by local councils or municitypical AWTS is shown in p alities. AWTS consists of Figure 1. Air primary and secondary tanks AWTSs with surface irrior compartments. The gation are generally designed secondary tank or compartto replace the conventional Influent me nt in turn co n sists of septic tank system s w here aeration, secondary settling tren ches or transpiration and disinfection/irriga ti on beds cannot be used due to chambe rs. the topography of a site (e.g. This paper discusses the on steep and sloping sites), design considerations for soil type (e.g. sandy zone or each of the above compartsoil with very low permements/chambers of AWTS ability) or water table and Section A-A and com1nents on the results reu se considera tion s. They have also become of a brief survey of field Figure 1 Typical arrangement of various components in an aerated a substi tute to pump- out septic tank system performance.

0

--

28

WATER JULY/AUGUST 1 998


WASTEWATER Table 1 Design and operating parameters for the aeration tank (Metcalf and Eddy, 1991)

Table 2 Typica l specifications for domestic AWTS air blowers (Spooner, 1994)

Values

Item

Air blower

Hydraulic detention time, h

24-36

Solids retention time, d

20-30

Type Voltage, volt Frequency, Hz Air flow rate, L/min Operation Housing

Electric motor and diaphragm blower 220-240 50 60-110 Time switch controlled Motor, blower and controls are housed in a louvred metal or fibreglass control box mounted on the lid of the tank

Parameters

F/M ratio, kg BODsfkg MLVSS.d

0.05-0.15

Volumetric loading rate, kg 80Dsfm3 .d

0.16-0.4

Mixed liquor suspended solids (MLSS), mg.IL

3000-6000

Mixed liquor volatile SS (M LVSS), mg.IL

2400-4800

Table 4 Typical specifications for domestic AWTS irrigation pumps (Spooner, 1994) Table 3 Typica l design values for the secondary chamber (Metca lf and Eddy, 1991; WEF & ASCE, 1991) Design parameters

Values (fo r ave rage flow condit ions)

Overflow rate, m 3/ m 2 .d Solids loadi ng rate,

kg/m 2 .h

Detention time, h

systems to avoid over-flowing and frequent pump-outs. In 1988, it was reported that there were about 2000 AWTS installations in NSW (Makestos, 1988) . This indicates the degree of acceptance by both co nsumers and councils, and fo r this reason a detailed study into the design of AWTS is considered important. Design details and limited discussions on the field pe rformance of AWTS are presented h ere. For more detailed discussions on efflue nt quality and performance see Khalife and Dharmappa (1996).

Design of AWTSs Generally, AWTSs operate on the principles of activated sludge or trickling filter processes u sed in centralised wastewater treatment plants. Accordingly, AWTSs u sually include the following components: • baffled or compartmentalised pnmary chamber • aeration chamber • sedimentation chamber • disinfection/irrigation chamber • final disposal area • controls and alarms. As shown in Figure 1, all these components can be incorporated in one circular tank. In some cases there may be two tanks, one for primary and another for secondary treatment of wastewater. The seco ndary tank is divided into aeration, clarification, and disinfection/irrigation chambers.

Primary Chamber The primary chamber receives influent wastewater from the household. It is normally compartmentalised or baffled in order to achieve better removal of settleable and floatable solids. The primary chamber is designed to accom-

8-16 1-5 3 - 10

Item

Irrigation pump

Type Voltage, volt Frequency, Hz Flow rate, L/min at 4 m head Output, W Operation Maximum runtime, min/d

Fully submersible dra inage pump 220-240 50 130-280 245 Automat ic st op/start, float switch 20

modate the sludge accumulation for a period of 1-2 years and retain the wastewater for 1-2 days. This allows some biological degradation of solids to take place through anaerobic digestion. Generally, some 50-60% removal of BOD and SS is achieved. The capacity of the primary tank is given by: Vp = nSP + twQP

(1)

where: Vp = volume of the primary tank, L n = desludging frequency, yr S = rate of sludge and scum accumulation, L/capita.yr P = number of persons u sing the system, capita Cw = detention time for the wastewater in primary chamber, d Q = daily wastewater inflow rate, L/capita.d The average daily wastewater flow rate in urban and rural living areas varies between 150 and 200 L/capita.d (THS, 1996; Household Waste Treatment Committee, 1990). The rate of sludge and scum accumulation is usually taken as 80 L/capita.a (0.22 L/ capita.cl) THS, 1996; SAHC, 1995). Most Australian cod es refer to population load as a function of the number of bedrooms in computing septic tank capacity requirement. In the Northern T e rritory, a population of two per bedroom is used (THS , 1996). This assumption does not reflect the actual population load under some circumstances, su ch as Aboriginal and rural communities where the actual population can be significantly different from these compu ted values (Khalife et al., 1997).

Aeration Chamber The primary settled wastewater overflows into the aeration chamber,

w here the o rganic materials are degraded aerobically. Care is taken in designing the transfer pipe so that the settled solids and scum (floatable solids) are excluded from entering the aeration chamber. Often, the aeration chamber is divided into two compartments that are connected in seri es. This helps in achieving plug-flow regime for the aerobic treatment (Metcalf and Eddy, 1991 ). Aeration is achieved in the aeration chamber(s) either by directly introducing air using blowers (activated sludge principle-see Figure 1) and/or installing a porous media (trickling filter principle). A system incorporating diffuse aeration and support medium should be able to maintain high bacterial mass within the reactor. However, in the present study only aeration systems using air blowers are considered. The volume of the aeration chambe r can be computed by: Va = taQP

(2)

where: ta = detention time for the wastewater in the aeration chamber, d. The detention time for the aeration chamber is usually taken as one day (THS, 1996). This means the aerobic activity which takes place within the aeration tank is of extended aeration type (Metcalf and Eddy, 1991). Comparing this process with the conventional activated sludge process, th ere are two benefits: minimum sludge production and high quality effluent. Typical values for the design and operating parameters of the aeration tank are given in Table 1. The amount of air required in the aeration chambe r is based on the following two criteria: (i) oxygen required for aerobic degradation; and WATER JULY/AUGUST 1998

29


WASTEWATER Table 6 Other design criteria for AWTS (AS 1546, 1994; SAHC, 1995; Laak, 1980)

Table 5 Irrigation system specifications (Khalife, 1995) Description Irrigation pipe diameter, mm Irrigation pipe material Minimum irrigation line cover, mm No. of microjet spray heads

Value

Low density polythene 100 25 to 35

Spray head discharge, l/min.

0.75

Spray distance at 0.5 bar (sprayed in 180° arc), mm

600

Approx. trajectory above ground level, mm

300

Typical eva poration rate, mm/d (for a vegetation cover of 40%, assuming 30% of deposited water is lost through transpiration)

Description

25

6

Criteria

Freeboard, mm

200-300

Operating depth, mm

Min. 900

Pipe diameter and all passage spaces, mm

Min. 100

Cylindrical tanks- diameter, mm

Min. 1,120

Rectangular tanks: Internal width , mm Length/width ratio

Min. 950 1.5-1

Access open ing, mm Rectangular (length x width) Circular tank (diameter)

Min. 500 X 450 Min. 500

Thickness of access cover (concrete), mm

Min. 65

Sludge clear depth from w/w free surface, mm

Min.100

Table 8 Capacities of various components of AWTSs Items

Capacity For six people

For ten people

< 20

Primary tank, L Aeration tank, L Sedimentation chamber, L Disi nfection/irrigat ion chamber, L

2,280 900 265 300

3,800 1,500 440 500

< 30

Total tank volume, L

3,745

6,240

300

435

27

45

Table 7 Effluent standards (AS 1547, 1994) Parameter BOD5, mg/L Suspended solids (NFR), mg/L Free chlorine, mg/L Faecal coliform, cfu/m l

(ii) mixing requirement. The amount of air (oxygen) required for aerobic degradation can be computed by (Metcalf and Eddy, 1991): = QP(So- S)(l ) 3 273 y-l.42 Yobs()

QA

where: QA = air flow rate required, L/d S0

= influent BOD 5 , mg/L

S

= effiuent BOD 5 , mg/L

f

= BOD 5 to BODL conversion fac tor (0.68)

Y 06 , = observed yield coefficie nt fo r microorganisms, mg/mg (usually 0.5 for domestic sewage) In addition, a certain amount of air is required to achieve complete mixing within the aeration chamber. Metcalf and Eddy (1991) recommend 10-30 L of air per min per 1,000 L of aeration chamber. Thus, the actual capacity of the air blower should be based on the maximum quantity of air required from the above two criteria. T ypical specifications for the air blower are listed in Table 2. Excess activated sludge in the aeration chamber is returned to the primary chamber using an airlift pump operated by the same blower that is used for aeration. This wastage from the aeration chamber is either continuous or intermittent. If the sludge waste 1s 30

WATER JULY/AUGUST 1998

Value

0.5-2.0 < 30

Irrigation area,

m2

Air flow rate required, Ljmin .

intermittent it should be adjusted using time controllers, so that the appropriate concentration for mixed liquor volatile suspended solids (MLVSS) 1s mamtained (as shown in Table 1). Sedimentation Chamber After aerobic treatment the wastewater enters the sedimentation chamber, where the activated sludge settles to the bottom and the effiuent is allowed to flow over to the disinfection/ irrigation chamber. The sedimentation chamber i s designed wi th a hopper bottom, w hich is open. This permits the sludge containing the bacteria to be recycled back into the aeration chamber. In some system s, a scum return system operating continuously or intermittently returns floatable solids to either the primary or the first aeration chamber. The scum return system is also operated using the same air blower. The sedimentation chamber performs the same function as that of the secondary settling tank used in activated sludge processes. As such its design is based on the overflow rate. Design parameters for the secondary chamber are given in Table 3. The volume (Vs) and surface area (As) of the settling chamber can be computed by:

Vs = tsQP/24

(4)

As = QP/v 0

(5)

w here: ts = detention time in the settling chamber, h

v 0 = overflow rate, m 3/m 2 .d The operation of the sedimentation chamber should be checked against the solids loading rate (see Table 3) . Disinfection/irrigation Chamber The wastewater is disinfected using chlorine tablets prior to its use for irrigation. These should kill all pathogenic bacteria and minimise health hazards. The contact between the wastewater and chlorine table ts is provided within a PVC pipe. The c hlorine- contac ted wastewate r flows into a disinfection/irrigation chamber and the wastewater is pumped out at regular intervals. This may be automated using a level sensor. Generally, the purpose of the disinfection/irrigation chamber is twofold: to provide sufficient contact time fo r the satisfactory disinfection of the wastewate r; and to provide sufficien t storage fo r the treated wastewater before being pumped out for irrigation. Both factors should be taken into account while designing the disinfection/irrigation chamber. Metcalf and Eddy (1991) recommended a c hlorine contact time between 15 and 45 minutes. On the other hand, an AWTS irrigation pump is operated for about three times a day, thus requiring the storage of the treated wastewater for about eight hours before every pump-out. H ence the detention time required for the disinfection/ irrigation chamber should be eight


WASTEWATER Table 9 Process parameters for AWTSs stud ied Site no.

No. of occupants

MLSSin aeration tank, mg/L

Volume of aeration tank, m3

Influent B0D5, mg/L

Wastewater flow rate, L/d

Volumetric loading rate kg B0Dsfm3 .d

F/M ratio, d-1

Effluent B0D5

Effluent SS, mg/L

10 13 16 17

5 6 4 5

49 24 59 49

2.05 1.47 2.05 1.48

161 47 508 168

750 900 600 750

0.06 0.03 0.15 0.09

1.5 1.5 3.15 2.2

2 64 16 64

12 118 79 660

Note MLVSS is calculated by multiplying the MLSS values by 0.8

hours, which is the greater of the above two requirements. T ypical specifications fo r the irrigation pump are listed in Table 4.

Flnal Disposal Area The eilluent from AWTSs is most commonly disposed of through surface irrigation. T he size of the irrigation area can be calculated by: Ar = 100 + PQ/II

(6)

where: Ar = irrigation area required, m 2

the installation of A WTSs is given with the condition that the eilluent meet these standard s. Such eilluent could b e used for irrigation. However, t he regulation prohibits the use of this wastewater for growing edible fruits or vegetables. There are indications that these eillue nt standards w ill become more stringent. For example, recently the Northern Territories H ealth Services (THS, 1996) recommended a faecal coliform level of less than 10 cfu/100 rnL fo r eilluent which is to be reused for surface irrigation purposes.

II = irrigation rate, L/m2 .d

Design Example

The irrigation rate dep ends on the soil type and evaporation and rainfall rates. The relationship between soil p e rmeability and irrigation rate is given in AS 1547 (1994). THS (1996) suggested a value of 4.5 L/m2 .d for the irrigation rate. The irrigation area computed using Eqation (6) includes the additional land area required (100 m 2) for social and recreational purposes of the h ousehold (THS, 1996). Efiluent pumped out of the irrigation chamber is conveyed through polyethylene pipes and applied on the irrigation area using spray h eads. The specificatio ns for irrigation lines and spray heads are given in Table 5.

T he capacities of all AWTS components are selected to satisfy appropriate residence time and treatment for the wastewater. Based on the design criteria presented above, capacities for various components of AWTSs are computed for treating the wastewater from six- and ten- person dwellings. The compartment capacities shown in T able 8 are based on the following assumptions: • average wastewater flow rate = 150 L/capita. d • sludge accumulati on rate 80 L/capita.yr • influent BOD 5 = 330 mg/L • desludging frequen cy = 1 yr • detention time for the wastewater in primary chamber = 2 d • detention time in aeration chamber =1d • detention time in settling chamber = 7 hr • detention time in disinfection/irrigation chamber = 8 hr • wastewater irrigation rate = 4.5 L/ m 2 .d • volumetric loading rate for aeration chamber = 0.33 kg BOD 5 /m3.d

Alarms As AWTS includes a number of mechanical and electrical components, it is necessary to equip them with an alarm to warn the user of any failures. The alarm comprises both audible and visible components, with muting facilities for the audible component. For domestic systems, the alarm may be positioned inside the building, preferably in the kitchen o r laundry. Other Design Criteria Other design criteria that should be taken into account during AWTS construction and installation are similar to those used in conventional septic tank systems (CSTSs). Some of these criteria are listed in Table 6.

Effluent Standards The eilluent standards specified by the N ew South Wales H ealth D epartment are listed in Table 7. Approval for

The required air flow rate computed in Table 8 is based on the mixing requirement, since the air supply based on the oxygen requirement in Eqn. (3) for aerobic degradation w as found to be only 0.7 L/min for a six- person system. This is far below the aeration required fo r maintaining the completely mixed conditions in the aeration tank. Thus, for most of the AWTS design, the second criterion governs the decision on air blower capacity. The typical air blower listed in Table 2 appears to be

oversized. Over-aeration can result in the shearing of biological floes in the ae ration tank, w hich could lead to carry-over of BOD/SS in the eilluent from the sedimentation tank. H ence, it is necessary to size the air blower appropriately based on the actual requirement.

Cost of AWTS A typi cal domestic A WTS costs betwee n A$2,000 and A$-S,000, depending on the size and type of the system. The operation and maintenance cost is estimated at A$200 to $280 per year (Khalife, 1995). Currently, it is estimated that there are about 15 to 25 manufacturers supplying various types of A WTSs in Australia.

Performance of AWTSs In order to study the performance, several AWTSs were selected within Campbelltown City Co uncil area. T hese systems were monitored for both process parameters and influent and efflu ent qualities. The influent and efflu ent qualities are discussed in Khalife and Dharmappa (1996). In this paper, the process parameters are presented and the implications of these parameters on the performance of the AWTS are discussed. Process Parameters Four AWTSs were briefly surveyed for determining the operating parnmeters within the aeration tank. Particularly, the MLSS concentrations were determined for each AWTS through grab sampling. These are presented in T able 9. As show n, the MLSS concentrations ranged from 24 to 59 mg/L, far below the concentrations recommended in T able 1. This could b e due to: • settling of biological sludge within the aeration tank because of inadequate nuxmg • carry-over of the sludge by the eilluent from the settling chamber • excessive wastage of activated sludge from the sedimentation chamber back to the primary tank • a combination of all of these factors. As sh own in Table 9, the efiluent from two of the AWTSs contains high suspended solids (SS), which indicates that there may be a carry- over of biological solids by the efflu ent. In WATER JULY/AUGUST 1998

31


WASTEWATER addition, during field trips it was observed that often the aeration system was not functio n ing appropriately (Khalife, 1995). This has resulted in the settling of the solids within the aeration tank, which in turn led to anaerobic conditions within the reactor. This can result in the sludge bulking in the settling chamber, thus finally culminating in the carry-over of solids by the effluent. The carry-over of solids can also occur due to the accumulation of sludge within the settling chamber. T his can be due to the blockage of the internal sludge recirculation passage (see Figure 1). Also, the activated sludge may be p revented from building up in the aeration chamber by its excessive wastage back to the primary chamber, as the wastage in most AW T Ss is continuous without any control on its quantity. Thus, the low MLSS concentration in the aeration tank could be attributed to all these reasons. H owever, furt h er investigations are needed to accurately pi npoint the most probable reason. From a fu rther comparison of the F/M ratio and volumetric loading rate between the observed (Table 9) and recommended values (T able 1), it is evident that although the volumetric loading rate is significa n tly low, the F/M ratio is sub stantially high. This is a direct consequence of the low MLSS w ithi n the aeration tank i.e., an insu fficient bacterial population to degrade incomi ng organic matter. This explains the presence of high five-day biochemical O>-.'Ygen demand (BOD 5) in the effluent (Table 10). T his was discussed in an earlier publication (Khalife and D harmappa, 1996). H owever, in the case of AWTSs located at Site Nos. 10 an d 13, as shown in T able 9, despite the very low MLSS values, the BOD 5 values were fo und to be quite accep table, meeting the effluent standard given in Table 7 . This may be attributed to low inflows into the AW T Ss during the grab sampling periods. The above discussion implies that although AW T Ss are designed wi th adequate capacity, they are not maintained and operated efficie n tly. The main operating problem seems to be related to the maintenance of adequate concentration of bacterial mass in the aeration ta nk . In the light of this fi nding, some of the modified A WTS systems, such as the one that uses plastic media for allowing the microorganisms to attach and grow, appear to b e u seful. Nevertheless, a clear understanding of AW T S operation and maintenance of appropriate process cond itions are essential fo r ach ieving good quality effl ue n t from A WTSs. In addition , fu rther research is required to improve 32

WATER JULY/AUGUST 1998

the existing AWTS designs to make them more user- friendly.

Conclusions Aerated wastewater treatment systems are the most widely used on-site waste disposal systems in the u nsewered areas of Australia. However, there is not enough technical literature docu menti ng their design and operation. T he primary aim of this paper is to compile all the relevant literature to document the design specification s of aerated wastewater treatment systems and to evaluate thei r performance using process parameters. D epending upon the manufacturers, there may be wide variations to the design specifications listed in this paper. Moreover, the re is a wide variety of proprietary products in the market whose design specifications may be qu ite d iffe rent from th e o ne presented in this paper. A li m ited su rvey of four AWTS i ndicated that the M LSS concentrations maintained within the aeration chamber were far too low (average 45 mg/L). Operational deficiencies appear to be attributable to aeration volu me, sequential operation and the system for diverting waste activated sludge . A modified AW T S with plastic media as support fo r the growth of microorganisms may be better suited for on- site waste disposal systems, as th ey can effectively retain the biological mass. Further research should be conducted for modifying existing A WTS designs to make t hem more u ser- frie ndly, particularly in relation to the maintenance of the disinfection system and correct operatio n and maintenance.

Acknowledgements The authors thank the staff at Campbelltown C ity Council , New South Wales and particularly Andrew Spooner who helped in the site inspection, testing and data collection. T he authors extend their sincere gratitude to the Environmental H ealth officer, Tony B ies of South Western Sydney Area fo r the relevant information on septic tank systems and Frank Bishop of C M PS&F International , Melbourne O ffice for his very useful comments on the draft of this paper.

References AS 1546 (1990) . Small Septic Tanks. Standards Australia, North Sydney, NSW. AS 1547 (1994). Disposal Systems for Efiluent from Domestic Premises. Standards Australia, North Sydney, NSW. B ies T (1994). Personal commun ication. South Western Sydney Area Health Service, Public H ealth U nit, Liverpool, NSW.

Household Waste Treatment Committee (1990). Septic Tanks Code of Practice. Environment Protection Authority Victoria, Department ofWater Resources Victoria and Health Department Victoria, Melbourne. Khalife MA (1995). Septic Tanks Design and their Applications in Australia, ME (Hons) T hesis, Dept of Civil and Mining Engineering, U niversity of Wollongong, NSW. Khalife M A and Dharmappa H B (1996) . Performance Evaluation of Aerated Wastewater T reatment Systems (AWTS) . Water, Aust. Water and Wastewater Assoc., 23, 5, 25-28. Khalife MA, Dharmappa H Band Sivakumar M (1997). P erformance Evaluation of Conventional Septic Tank Systems in Rural Communities. IAWQ Asian Regional Conference on Water Q uality and Pollution Contro l, 20-22 May, Seoul, South Korea, pp.1779-1791. Laak R (1980). Wastewater Engineering Design for Unsewered Areas. Apn Arbor Science Publishers, Michigan. Makestos M (1988). Domestic Wastewater Treatment and Disposal, Options for Unsewered Areas. Water, Australian Water and Wastewater Association, 15, 4, 15 . Metcalf & Eddy (1991). Wastewater Engineeti ng: Treatme,it Disposal Reuse. 3rd Edition, McGraw Hill, New York. SAHC (1995). Standard for the Constrnction, Installation and Operation of Septic Tank Systems in South Australia. Public and Environmental Health Branch, South Australian Health Commission, Adelaide. Spooner A (1994). Personal communication. Health and Building Department, Campbelltown City Council, Campbelltown, NSW. THS (1996). Code of Practice for Small Onsite Sewage and Sullage Treatmen t Systems and the Disposal or Reuse of Sewage Eilluent. Environmental Health Program Directorate, Territory Health Services, Department of Housing and Local Government, Darwin NT. WEF & ASCE (1991) . Design of Municipal Wastewater Treatment Pla12.ts. Water Environment Foundation & American Society of Civil Engineers, Alexandria, VA.

Authors H B Dharmappa is a Senio r Lecturer in Environmental E ngineering in the D epartm en t o f Civil, Mining and Environmental E nginee ring at t he U niversity of Wollongong, Northfields Avenue, Wollongong NSW 2522. H is main research activities include on- site waste disposal systems, the design of water and wastewater treatment plants and sludge treatment and disposal. M A Khalife is a PhD student at the U niversity of Wollongong who worked with Campb ell town C ity Coun cil during 1994 to investigate the performance of aerated wastewater treatment system s. His d octo ral studies involve the safe disposal of wastes in remote Aboriginal comm unities.


BOOKS Activated-sludge Treatment P R oberts (ed.) Chartered Institute of W ater & Environmental Managem ent, UK, ISBN 1 870752 32 5, 207 pp, N ovember 1997, £35 CIWEM members, £ 40 non m embers plus 10% postage, Lavenham Press, 47 W ater St, Lavenham, Sufiolk, CO10 9RN This miniature handbook is a very substantial revision of the 1987 ha ndbook produ ced by the now defunct U K Institute of Water Pollu tio n C ontrol. Im po rtant n ew areas covered include nu trient rem oval m echanisms, microbiological factors which affect sludge settleability, control of bulking and foa ming, modelling of population dynamics and sequen cing batch reactors. T he history and development of the activated-sludge process are covered, as well as relevant scientific concepts such as mi crobiology, settling, flow co nfiguratio n s an d ae ratio n. Basic process design , t he pumping and han dling o f sludge and biological nu trie n t rem oval are also covered . Process m odifica tion s such as the SBR sys te ms, fluidized beds, oxidatio n ditches and the use of ' pure' oxygen are included. Finally, operation and control is explained in the last chapter and m aterial on basic kine tics, nitrifi -

ca tion/de nitrification, testing of aerators is supplied in the appendices. I fou nd this book a pleasure to read. Its stated aim is to present ' the broad range of available tech niques ... in a readily understandable form .' The text was lucid, so it achieves its aim admirably. Personally I would have liked to see a sectio n included w hich describes h ow one would take a wastewater and evaluate it for treatabili ty. H owever, the editors presumably felt thi s sort of laboratory mate rial was o utside the scope of their handbook. It should also be noted that one gen eral aim of the publisher is to present m anuals p repared ' notably in respect of British Practice.' Accordingly, the 200 refere nces are ve ry h eavily biased towards UK material. It is also worth noting that the handbook also con tains ve ry u seful tastefully presented comments regarding th e limitatio n s of the IAWQR publicatio ns on pro cess modelling of activated- sludge processes. The book, at £35 CIWEM members and £40 non m e mb ers, is a little expe nsive fo r a paperback edition . Nevertheless, I recom m end i t for purchase. A lan Holder

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ENVIRONMENT

¡

ENVIRONMENTAL IN RURAL VICTORIA: AN UPDATE A Hinwood, R Bannister, A Shugg, M Sim Summary This paper presents an update on arsenic concentrations in soil, su rface water and groundwater in areas w here previous data and anecdotal information has indicated the presence of inorganic arsenic at elevated concentrations. Available data on arsenic concentrations in a range of environmental media are presented. Data w hich was collected as part of an investigation into the potential for absorption of arsenic by residents exposed to environmental arsenic is also presented and adds to the current information base on arsenic concentrations in rural Victoria. These data confirm some of the previously obtained data on h igh concentrations of arsenic in soil, groundwater and surface waters in the central, north-eastern and western districts ofVictoria.

Introduction Arsenic is present in the Australian environment both naturally and through activities such as pesticide use, gold mining and past inappropriate waste disposal practices. T he concentration of arsenic in the environme nt varies considerably depending on the geohydrology of a region and any largescale industrial, agricultural or mining activity. In studies investigating environmental exposures, inorganic arsenic has been associated with cancer at several body sites including the lungs, bladder and liver (Tseng et al., 1968; C hen et al., 1985; Wu et al. , 1989; HopenhaynRich et al., 1996). Arsenic has also been associated with a range of non-cancer health outcomes including vascular disease and two recent studies have suggested arsenic in drinking water may 34

WATER JULY/AUGUST 1998

be associated with diabetes melli tus focused on arsenic (HCS, 1995). (Engel & Smith, 1994; Wu et al., 1989; As part of the Environmental Arsenic Study (EnvAs) conducted by the Engel et al., 1994). In 1991 the D epartment of Manu- Department of Epidemi ology and facturing and Industry D evelopment Preventive Medicine at Monash U ni(DMID) of Victoria completed a study versi ty further environmental samples which collated data on arsenic concen- have been analysed for their arsenic trations in the Victorian environment. concentrations to identify populations Concentrations reported in the 1991 which may be exposed to arsenic from Victorian study were based on surface environmental sources. This p aper soil and groundwater samples taken in presents these results and updates the several old gold mining areas of central information base on environmental north-eastern Victoria (DMID, 1991). arsenic concentrations in rural Victoria. The study foc used on areas w h ere mining activities had taken place and Materials and Methods obtained information on environmental arsenic concentrations from a range of Data Collection Data was collected in two phases. sources. This information was subThe first phase located previous data on sequently tabulated and mapped. Reported arsenic concentrations in arsenic concentrations in rural Victoria . surface soils ranged up to 36,000 mg/kg. This data was obtained from the 1991 High concentrations in grou ndwater DMID report, the Rural Water Corwere also reported in some areas, poration database (1994), Locat Governranging up to 300 mg/L. The current ment Reports, the Victorian EnvironANZECC/NHMRC health investiga- mental Protection Authority's Register tion guideline for arsenic in soil is 100 of Confirmed Contaminated Sites and mg/kg. The NHMRC drinking water the Department of Health and Comguideline has recently been reduced munity Services (1995). The second from 50 to 7 Âľg/L (ANZECC/NHMRC, phase involved regional collection of soil, groundwater and surface water as 1992; ARMCANZ/NHMRC, 1996). Most of the analytical data and other indicators of arsenic con centrations for information provided in the DMID sampling. Where samples indicated the report was not collected in a systematic presence of arsenic at greater tha n fas hion and it is likely that differe nt current guidelines or standards, further sampling and analysis techniques were sampling was conducted on a household used. Comparison of data is difficult and basis. Groundwater and surfac e water the data may not, therefore, have been samples were collected in acid-washed representative of the areas identified. Since the 1991 DMID report there polyethylene 500 ml bottles from acceshave been a number of specific contam- sible bores and streams or rivers in inated site investigations as well as a identified areas. Drinking water samples study commissioned by H ealth an d sourced from groundwater or surface Community Services (HCS) in 1994 to water were taken from 106 household determine the water quality of drinking kitchen taps three times throughout the water in rural Victoria which have year.


ENVIRONMENT Surface soil samples were collected from selected locations in identified areas and composited for analysis. This method was not in accordance with AS 4482.1-1997. Soil samples were also taken from 106 residences in eight areas of rural Victoria. Surface soil samples were taken in a grid pattern using a 37 mm bore auger and composited before analysis. Although this method of sampling has the potential to under- or over- estimate the concentration of arsenic in soil in select locations, it was used b ecau se the cost of analysing samples from individual locations from a given property was prohibitive. The method was u sed to provide an indication of wheth er soil was a potential exposure source fo r residents in these areas. Water Analysis Inorganic arse nic was analysed in urine and water by continuous flow hydride generation atomic absorption spectrometry (AAS) , which measures inorganic arsenic only. Digestion is required for detection of total arsenic, including organic arsenic. Arsenic is normally present in both the tri- and pentavalent oxidation states. The analytical sensitivity of As (III) is normally twice that of As (V) using the hydride technique. Before m easurement all As (V) was reduced to As (III) by acidifying the sample with concentrated HCl to give an approximately 2M solu tion and adding 0.1 %w/v KI. Approximately one hour was allowed for the reduction to proceed at room temperature. Sodium borohydride (NaHB4) was used to create gaseous arsine (AsH 3) upon reaction of the acidified specimen. Once formed and separated from the liquid, the hydride vapour was carried by a flow of inert gas (argon) to a heated quartz absorption cell where thermal d ecomposition occurred under an oxidising flame. T he amount of light absorbed by the elemental arsenic was measured by an atomic absorpti on spectrometer. T he detection limit was 1 Âľ g/L for water. Soil Analysis Soil samples were analysed by Water Eco scie nce. Composite soil sa mples were mixed, sieved and freeze- dried and a portion was selected for arsenic analysis. The soils were digested using nitric and perchloric acid, treated w ith NaBH 4 and detected using AAS. The detection limit used was 1 mg/kg. Every assay included quality controls in o rder to determine assay p erformance. Internal quality controls were spiked at low and high concentrations in urine. These were run in duplicate

for all assays. An external quality program was also used by the Victorian Institute for Forensic Medicine (VIFM) (Quality Control T echnologies, C harlestown NSW 2290).

Results Table 1 shows the arsenic concentrations reported in previous reports of arsenic concentrations in the environm ent. The wide range for each location is due to information drawn from different data sources, with the likelihood of different methods of analysis, as discussed above. Table 2 shows the results of analyses of both regional samples and residential samples taken for the EnvAs Study. The median and range of concentrations for each area are presented where sufficient samples were taken for both regional and residential samples . The areas marked with an asterisk are those w here household samples were obtained. Figure 1 shows those areas where arsenic con centrations exceed current standards or guidelines for d rinking water and soil.

Discussion The results of the E nvAs stu dy co nfirm th e enviro nme ntal arse ni c concentrations in rural Victoria for many areas and provides some data on arsenic levels in additional locations. All areas which show concentration s above the ANZECC/NHMRC health

investigation guideline for soil of 100 mg/kg and the NHMRC drinking water guideline of 0.007 mg/L include those with naturally high concentrations of arsenic in the media or have b een contaminated in the gold mining process. Arsenic is associated with gold mineralisation and its concentration in tailings and waste material are principally dictated by the original concentration in the ore material. It is therefore not surprising to find such high concentrations in areas w here mining has occurred and tailings are present, such as in Golden Square (Bendigo) where concentrations were found to range up to 16,000 mg/kg arsenic in soil on residential properties. T he data presented provide further information on environmental arsenic concentrations and will assist in identi--' fication of areas w hich may require furthe r sampling to assess the potential for arsenic absorption in residents who live in these areas. The data show that, for most areas, the concentration ranges are very large, although the median is frequently quite low. This indicates that the re must be hot spots of high contami nation. It is therefore imperative that in the presentation of data both the central tendency of system atically collected data and the spread of data be provided. T hese issues are important for any assessm en t of arsenic contamination and whether the

Table 1 Reported ra nge of arsenic concentrations in soil and water Location

Avoca Balla rat Bendigo A Bethanga Chewton Cost erfield Daylesford Dromana Eaglehawk Li llimur MacArthur Maldon Mepunga Mt Egerton Nhil l Rosebud St Arnaud Swifts Creek Woods Point

Groundwater

Surface water

Soil

(mg/L)

(mg/L)

(mg/kg)

Data source

<0.001-0.3(62) 0.5-5(3) 0.02 - 12 (59)* 0.0 6-0.78 (5)* 0 .1 (1 )* <0.001 - 0.74 (4)* 0.014 (1)* 0 .018 (1) 0.002-0.72 (2) 0 .009 - 0 .0 62 (7) 0.4 (?) 0 .006 - 0 .1(2)* 0.8 (1)

0.01- 2.83 (514)

<5-383 (20) 1 -3106 (173)

<0.001-0.003 (3)

28- 10190 (18)

<5-710 (21)

59 (1) 14 5 - 300 (2)

0.007 -0.016 (20) 0 .018 (1) 0.1 (1)* <0.001 -0.049 (11)

1300-15000 (5)

3 00 (1)*

3 3 3 3 3 3 3 1 3,4 2 2 3 1 4 2 1 3 3 3

* Mine sample included ( ) number of samples Data Source 1 = RWC database 2 = H&CS Arsenic in Drinking Water, April 1995 3 = DMID 1991 4 = Local Council

WATER JULY/ AUGUST 1998

3~


ENVIRONMENT Table 2 Range of arsenic concentrations in soil, groundwater and surface waters from the current EnvAs study

Groundwater

Surface water

Soil

Drinking water

(mg/L)

(mg.IL)

median range (n)

median range (n)

(mg/kg) median range (n)

median range (n)

Location

Golden Square* Pilot Trial EnvAs Bethanga * Screen EnvAs

0.002

0.001-0.003 (4)

Chewton

0.019 DL

Costerfield

360 225

40-16800 (33) 14-9900 (12)

DL

DL-0.003 (12)

245 49

130- 1100 (4) 11- 340 (13)

DL

DL-0.026 (23)

DL-0.003 (3)

0.002-0.008 (2)

0.003 (1)

0.002 - 0.6 (3)

.002 - 0.003 (2)

Daylesford Harrietville

0.004-0.22 (4)

DL (2) 0.003

Kaniva

6.4

4.1-10 (6)

Lillimur

4.1

3.8-5.2 (5)

Maldon

DL-0.003 (2)

Merino Nhill* Screen EnvAs

0.007

0.001 -0.012 (3)

Rushworth

0.005

58

9.1 - 160 (13)

DL

DL-0.003 (14)

9.1

3.4-30 (19)

0.042

DL-.073 (4 1)

4.6 3.2

2.2-13 (7) 2.7-6.1 (3)

.005

0.0 03 - 0.012 (4)

9.0

4.7-290 (12)

DL

DL-.0 64 (17)

29 29

7.4- 1600 (28) 11-71 (4)

.002 0.006

0.001 -0.12 (26) DL-0.041 (8)

3.3

1.7 - 80 (26)

DL

DL-.010 (25)

DL-0.050 (4)

0.001 (1)

St Arnaud Swifts Creek* Screen EnvAs Talbot

(mg/L)

0.028 - 0.074 (2) 0.0 01

0.001-0.003 (3)

Wandil igong* Pilot Trial EnvAs

0.001

.001-0.006 (6)

Woodend * Woods Point

0.005

DL-0.024 (6)

DL denotes analytical limit of detection * denotes areas where household samples were taken

concentrations reported warrant further attention in terms of the potential for absorption from residents living in these areas and the risk of public health impacts.

Acknowledgements The investigators thank the D epartment of H uman Services for meeting some of the costs of sample analysis and the following people who gave advice and assistance during this project from government and local agencies: Trevor Ingram, Peter te H ennepe, Doug Seeney, Paula Gough, Tony Wissenden, Derek Ligh tbody, Paul Bond, Rod Flavell, Max M urphy, Bob H anby, Bob Wallace, and T om Neederly.

References Australian and N ew Zealand Environment Council/ National Health and Medical Research Council (1992) Australian Guidelines for the Assessmenc and Management of Contaminated Land, Australian Government, Canberra. Chen C-J , Chuang Y-C, Linj-M , Wu H-Y (1985) Malignant Neoplasms Among R esidents of a Blackfoot D isease Endemic Area in Taiwan: High Arsenic

36

WATER JULY/AUGUST 1998

Artesian Well Water and Cancers. Cancer R esearch 45: 5895-5899. Department of Manufacturing and Industry Development (1991) Arsenic in the Environment. Stage 1 Report Natural Systems Research Environmental Consultants for Department of Manufacturing and Industry Development February 1991, Victoria, Australia. Engel R R and Smith A H (1994) Arsenic in Drinking Water and Mortality from Vascular Disease: An Ecologic Analysis in 30 Counties in the U S. Archives of Environmental H ealth 49 (5): 41 8-427. Engel R R , Hopenhayn-R.ich C, R eceveur 0 and Smith AH (1994) Vascular Effects of Chronic Arsenic Exposure: A R eview. Epidemiologic Reviews 16 (2): 184-209. H openhayn-Rich C, Briggs M L, Fuchs A, Bergoglio R, Tello EE, Nicolli H , Smith AH . (1996) Bladder Cancer Mortality Associated w ith Arsenic in Drinking Water in Argentina. Epidemiology 7: 117-124. National H ealth and Medical Research Council/ Agricultural and R esource Management Council of Australia and New Zealand (NHMRCfARMCANZ) (1996) Australian Drinking Water Guidelines. Australian Government Publishing Service. Standards Australia (1997) Australian

Standard Guide to the Sampling and Investigation of Potentially Contaminated Soil. Part I: Non- volatile and Semi Volatile Compounds. AS4482.1-1997 . Tseng WP, C hu WM, H ow SW, Fong] M, Lin CS, Yeh S (1968). Prevalence of Skin Cancer in an Endemic Area of Chronic Arsenicism in Taiwan . J. Natl Cane. Inst: 40: 453-463. Wu M- M, Kuo T-L, Hwang Y-H, Chen CJ (1989). D ose Response Relation Between Arsenic Concentrations in Well Water and Mortality from Cancers and Vascular Diseases. Am.). Epidemiol. 130: 1123-1132.

Authors Andrea Hinwood is an Environmen tal Toxicologist completing her PhD and Dr Malcolm Sim is an Occupational Physician in the D epartment of Epidemiology and Preventive Medicine, Monash Medical School, Alfred H ospital, Prahran Vic 3181. Dr Ross Bannister is a Co nsultan t Chemist with Wate r Ecoscience. Andrew Shugg is Groundwater Project Manager with the Victorian Department of Natural Re so urces and Environment.


ENVIRONMENT

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ENVIRONMENTAL MONITORING DATA

WHY?HOW? AND WHAT DO WE DO WITH IT? J Cugley Abstract This paper describes some innovative approaches to the use of environmental data in South Australia including the development of an environmental data management system (EDMS) for the storage and management of air, water, noise and soil monitoring data and the use of control charts to assess performance. It also presents some thoughts on a more flexible approach to environmental regulation.

Introduction

of other agencies, began an ambient water quality monitoring study covering some of the key water bodies around Sou th Australia. The purpose of t his program is to provide a broad assessment of the State's water bodies, determine long-term trends and provide data for State of Environment reporting and oth er national assessments of th e quali ty of water resources. It is clear that these programs are gene rating considerable quantities of data and important that the data be stored securely and properly managed. It is also important that the data be integrated so that a complete picture of what is happening can be de termined. For example, if ambient monitoring indicates a possible problem it is important to have discharge data at th e end of the pipe that can help to establish w here the problem lies.

With the proclamation of the South Australian Environment Protection Act in 1995 many industries that were previously unlicensed and operating quite lawfully found they needed a licence from the South A u stralian Environment Protection Authority (EPA) in order to operate. In many cases where the industry was discharging to a receiving wate r co nditions were attached to the licence that required the licensee to carry out a monitoring External program and to report the results to the EPA with the Databa~, ' possibility t hat the data wou ld be made publicly available. It has taken some time for these requirements to be implemented but now, ____Data approximately two years down the track, most Ad Hoc ......--licensees are moving towards complying with their obliQuerying/ / Reporting gations an d undertaking environmental monito ring programs, at least to som e degree. Some have further Custom to go than others. Applications At the same time the EPA, in conjunction with and supported by a number Figure 1 Schematic layout of the EDMS

eI

~

G --~[:J G

Ju st as important is h ow the data are used to better understand the process so that informed changes can be made to improve performance. T he key is to turn data into information and information into understanding. The next few sections of this paper: • describe how the Sou th Australian EPA plans to manage its own data as well as data from licensees through the development of an environmental data managemen t system • provide some ideas on how the data can be used in a process control sense to better understand wha t is happening as well as achieve acceptable environmental outcomes • provide some insight into current thinking in the EPA on a different regulatory approach that places emphasis on good performance rather than strict adherence to regulations.

ODBC Links

lu~raphs

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....._____

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----....

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Statistics

Environmental Data Management System (EDMS) Basic System Requirements The EDMS is required to hold and manage air, water, noise and soil data gene rated by the various programs run by the South Australian EPA as well as data sent to the EPA by licensees and other agencies and organisations. T he data will be u sed fo r: • State of Envi ronment reporting • assessing the environmental condition of water bodies, air sh eds and parcels of land • assessing problems caused by noise and issues associated with waste depots and landfills WATER JULY/AUGUST 1998

37


ENVIRONMENT ;r,

l!lllill&l

EDMS - [Site Maintenance]

report on a number of sites and characteristics in one hit.

GIS Capability

Name

?="=="=="=="=="=="=="=9fi:5

~

Data Type Water quality ADDRESS: Street

Description~ = = = = = = = e ~ Agency Environment Protection Al AMG: AMGZone

nm-

AMG Easting

Suburb/Tow State

244,400 6,445,700

Postcode

Comments

-32.095928

Site Type DATA TYPE SPECIFIC: Elevation

138.291588

248 Altitude

Catchment Area

100! Dist From Mouth

Gauging Basin No

5091Gauging Station Noj

Longitude Depth

I

86 Bore No 5031

Gauging Basin Name Willochra Creek Basin

World Wide Web Interface

Figure 2 Monitoring site information details

• determining compliance with National Environment Protection Measures and other national gu idelines, standards or goals • providing the community with information on water, air, noise and soil pollution problem s • providing data on the effectiveness of various initiatives to improve environm ental performance. Holding these data in a central repository ca n assist in providing a big picture view of w hat is happening in an area. For example, in assessing data from a landfill it may be important to know the effect of leachate on nearby rivers, seepage into groundwater, air quality or du st experienced by nearby residents, and the effect of noise generated by trucks visiting the site. In the past access to t his data has been fragmented. Sometimes j ust finding where the data are located is difficult! In developing the broad requirements for the EDMS it was recognised that certain aspects of the system were essential in order for it to gain wide acceptance within the South Australian EPA and possibly by outside users. T he system had to be easy to use, support a wide range of PC-based software applications, flexible enough for changes to be made easily with minimal disruption and able to make use of recent developments in informatio n technology. The system ca n be represented diagrammatically as shown in Figure 1. The data are held in a central ORACLE database and serviced by a number of applications. Some of these applications are purpose- built such as those used for data entry, or they may be third party proprietary produ cts which can use the data but are indepen38

WATER JULY/AUGUST 1998

Being able to display information geographically was seen as an essential requirement of the system. Displaying base layers of information such as roads and rivers, overlaying the monitoring sites on top of them, and pointing at a site and clicking to get the monitoring results is a very intuitive way of getting data. After a detailed evaluation process it was decided to use Mapinfo as the GIS software tool but it can easily be swapped to another product at a later date should the need arise. The GIS can be accessed directly from within the EDMS or by standalone GIS software. Figure 3 demonstrates one of the capabilities of the GIS feature.

dent ofit such as Mapinfo GIS software, Excel, Word. The ability to plug and unplug applications is an important aspect of the design of the system. This gives considerable flexibility by being able to choose specific products as they become available without impacting on the core database. It also provides a cost-effective m ea n s o f obtaining capabilities that may not be achievable if they had to be purpose-built for the system.

Custom-built Applications More than 25 custom built applications have been developed such as the one shown in Figure 2 which records information about a monitoring site. Some interesting features of the system include: • the data are segmented by data type (water quali ty, air, noise etc. ), data owner and monitoring program. The user can select which segments they want to see. The choice can be very broad (all monitoring programs for all data owners fo r all data types), very narrow Gust one monitoring program for one data owner for one data type), or somewhere in between. T his enables u sers to select only the data that they want to see • the system store s guidelines or standards and these can be linked to monitoring sites. When data are reported, values that exceed the standard or guideline can be highlighted • biological and other data using a hierarchical structure can be stored on the system and searches can be made up and down the structure for data at a particular taxonomic level • monitoring sites and characteristics can be grouped making it easier to

Making the monitoring data available to the public is important to the EPA. The World Wide Web offers many attractions and it is proposed that the EDMS have a direct link to the Web. A prototype Web facility has been developed that enables users to have: • direct access through the Web to data held on-line in the EDMS database with users able to generate simple queries • access to contextual reports assessing the data • an interactive GIS capability that enables the user to access data more intuitively by pointing and clicking at monitoring sites on a map. Some o f these options are currently at the leading edge of what can be ac hieved through t he Web at the moment. Further work is required to convert this Web prototype into a fully functional system but the prototype has demonstrated that it is technically feasible.

Assessment of Environmental Data Some Fundamentals Monitoring data is of very little use by itself. The issue is how to turn it into information. A major stumbling block in the assessment of data i s t hat the interpretation of results from a monitoring program is first and foremost a statistical activity. Consider a set of 12-m onthly ammonia values in efiluent discharged from a sewage treatme n t works. Together they represent a tiny fraction of the total effluent that has been discharged during the period, perhaps no more than 0.00001 % of the total. Even if the ammonia concentrations in that tiny proportion of the efilue nt


ENVIRONMENT could be measured with perfect accuracy, they are of very little interest in themselves and are only useful because they give an indication of the ammonia concentration s over the w hole year. The question to be asked is, 'How reliable is this indication?' This process of using a fraction of the whole to make necessarily uncertain j udgments about the process is exactly what statistics set out to do. A key component in any statistical analysis of data is the determination of the degree of confidence that one might have in the result. The question should not be, 'Does the result exceed a specified limit?' but, 'What degree of confidence do I need to have that the process is w ithin acceptable bounds most of the time?' Instead of thinking abo ut waste treatment, picture yourself as a manager of a factory producing tomato sauce. If the product was runny one day and thick the next, o r red one day and orange the next, you would probably have trouble selling the product and may well go out of business. You would be very concerned about mai ntain ing q uali ty w ithin an accep table range. Waste discharge is no diffe rent. Y our customer is the environment and regulators such as EPAs are acting on behalf of the customer. Variations in t he quality of the product you are producing is certainly of concern to the EPA and should be of concern to you.

,.- Maplnlo Professional

P01t Rive, site 7 P01t River water quality sc chlorophyll a T1ich1omatic

The issue becomes how to measure and manage variations in quality. Control charts are used in many manu fact uring industries to assess quali ty and can be used j ust as easily for assessing environmental data. They are based on the concept of statistical control which involves setting performance ran ges be tween which t he process can be thought of as performing normally. This is called performing 'within control.' W h en measurements fall o u tside the normal range the process is called 'ou t of control.' Control charts focus attention on the 'out of control' occurrences and also o n the range of values within w hich the system is in control. Over time, and with a better u nderstan ding of the parts of the process that cause major variations in the quality of the discharge, the control limits usually narrow. Figure 4 is an example of a simple control chart. A control chart displays data chron ologically either by date or sequence number. A ssuming data are fairly evenly distributed about the mean , the upper con trol limit is placed at three standard deviations above the mean and

8

Count: Maximum: Minimum: Std Dev: Average: Median: Units: No. Esceeding Guidlines:

8.2 0.6 2.35884 2.9125 2.4

I

ug/L

0

Suspended Solids Data for a WWTP-1996 100-r-- - - - - - - - -- - - - - -- - - - - - - - i 90 · 80 · 70

60 50 -

40 - 30 -

Control Chart Approach

------------------- ------• ----- -------------------------·

....

• •• •• • ••• • • -• -+---- : • •• •••• • •• o+-- --t-- --+-

20

10

17/12195

='96

2003.'96

151'.lS/96

4/07~

2300/96

12/1~

Upper control limit Warning

, Estimated mean

1/12/96

Figure 4 Control cha rt for suspended sol ids discharged from a metropol itan sewage treatment plant

the warning limit at two standard deviations above the mean. If everything is operating well, 99.7% of the time the process can be expected to perform below the upper control limit and 95% of the time below the warning limit. Clearly there are a number of attractions to using control charts: • if the upper control limit is well below a specified limit the chances of exceeding the limit are small and it may be possible to reduce the frequency of monitoring (in fact you can calculate exactly how many samples you need to collect) • if the upper control limit is close to a specified limit there is an increased risk the limit will be exceeded and sampling may need to be increased. Steps can be taken to reduce th e upper control limit by reducing the vari ability in th e discharge. Effort is therefore focused on where it is needed

• they encourage an approach by regulators to recognise that limits may be exceeded on occasions and to set more realistic requirements based on statistical processes and acceptable confidence limi ts • atten tion is focused o n the 'out of control' occurrences.

Regulatory Approaches The 'exceed this level and bang you're gone' approach

T he traditional approach by regulators has been to set a standard in the form of a number or value that m ust never be exceeded under any circum stances. Failure to comply means eithe r a hefty fine o r possible prosecution through the courts. A number of questions arise about this approach: • Does it protect the environment or create opportunities for lawyers to get rich? WATER JULY/AUGUST 1998

39


ENVIRONMENT Table 1 Proposed flow chart for regulation Licensee to develop and mai ntain control charts for a sma ll number of key characteristics, e.g. suspended solids, ammonia, copper

Upper control limit (UCL) is set at mean plus three standard deviations and EPA requ ires UCL to be less t han a specified critical level

Exeeding the UCL is regarded as a 'failure'

Failures must be reported to EPA within 24 hours

Frequent failures (say 3 failures in a month) requires a bond to be lodged with EPA and an increased level of monitoring

Severe failu res (say, more than 3 per month) req uires a bigger bond to be lodged with EPA with further increases in frequency of monitoring and audit operation

performance wi th the necessity to take corrective action if a failure occurs. For example, the National Health and Medical Research Council (NHMRC) guidelines on recreational use of water (primary contact) state that the median value should not exceed '150 faecal coliforms p er 100 mL for a minimum of five samples taken at regular intervals not exceeding 1 month with 4 out of 5 samples containing less than 600 faecal coliforms per 100 mL.' T hus, a monitoring program that gave four results of 140 and one of 100,000,000 would meet the NHMRC require~ ments but would clearly be unsuitable for swimming on the day of the last measurement! C learly there are problems with this approach.

A More Flexible Approach Bond refu nded after 3 months of sat isfactory performance

• Does it encourage ' massaging' data so they don't exceed the limits? • What do you do when the li mit is not too far away from the limit of detection and your chances of exceeding the limit are increased? • How do you build in u ncertainty associated wi th measureme n t (for

example 5.9 may comply but 6.0 wilJ fail)? • Do you base compliance on means, medians, maximums, percentiles or what? • How often should you sample and where? Often standards and gu idelines confuse th e assessment of long-term

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The EPA in South Australia is keen to explore the development of a more flexible approach with licensees, but o ne which still ensures t hat the environment is protected. T he flow chart presented in Table 1 is heading in the right direction and the EPA i s worki ng on refini ng this approach . The attractions of this bond forfeit approach are: • it encourages polluters to understand their process and control the variability of their waste stream • poor performance is dealt with through an increasing scale of penalty • bond money is repaid when the operation returns to 'within control' but can be used to take remedial action if needed • legal action is avoided or minimised • occasional failures are permitted but frequent failures are penalised. T he difficulty of this approach is ensuring that reporting and monito ri ng are carried out properly, but this could be overcome by requiring spot audits or other means. T he South Australian EPA is investigating the bond forfeit approach with a small number of cooperative licensees. Time will tell if the system can be made to work efficiently.

Acknowledgements The South Australian Environment Protection Authority ackn owledges the assistance of Steven Rowe and Associates for their work in the design and development of the environmental data management system.

Author Dr John Cugley is Principal Water Quality Advisor, Office of Environment Protection Authority, Department for Environment, H eri tage and Aboriginal Affairs, GPO Box 2607, Adelaide SA 5001.


ENVIRONMENT

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COMMUNITY CONSULTATION Ar

AGNES WATER L MIiier

When councils or other water and wastewater authorities make decisions about the services they provide without adequately consulting their communities, problems invariably ensue, especially in pristine environments such as Agnes Water, ('Agnes' means 'pure' or 'chaste'). Concerned about the possible sullying of the waters and surrounding environment, Leonore Miller chronicles the saga of the provision of water and sewerage services to this small town on the Southern Central Queensland coast (Ed.). Having anchored in Bustard Bay in May 1770, explorer Lieutenant James C ook and botanist Jo seph Banks m ade their second landi ng in R ound Hi ll Creek in Queen sland , thus ensuri ng national significance as a cultural and natural he ritage area for this site betwee n G ladstone and Bu n daberg coast at the conjunction of the northernmost surfing beach and th e beginning of the Great Barrier R eef. Two cen turies later subdivision began, changing the face o f the area, crea ting the townships of Agnes Wate r and th e Tow n of 1770. T he coast attrac ted urban allotme n ts an d th e hinte rland provided rural-residential subdivision to the west and south to B affle C reek. Subdivision approvals allow fo r a population of 10,000, of wh om only 1,000 have take n up residence to date. Commun ity co ncern about effl uent seepage into the groundwater aqui fe r through septic tanks and developers' conce rns about future wa ter needs for commercial activity, led Miriam Vale Shire Cou ncil to begin water supply and sewage disposal planning during the mid 1980s.

The reticulated wa ter supply came on-line during 1992 . T wo tren ches were dug in th e back dunes at the h ead of R eedy Creek, to the sou th of Agn es Wate r. W ithin three yea rs it became appare n t t hat th ey wo uld not be suffi cient. By 1990 the C ouncil's proposal to pond sewage and spray- irrigate on a site on the banks of R ound H ill Creek cau sed co nside rable alarm to communi ty groups including the 1770 H eritage Group an d la te r the Agnes W ater Landcare Group w hich was formed in 1995. T he environme ntal risk of this form of treatment was too high. In January 1996 the Landcare Group conducted a field day to explore optio ns and bring people toge ther. Landcare Exten sion Officer H eather Beever organised for Peter Beavers, Exec utive Engineer wi th Local Auth ority T ech nical Services from the D epartment of Natu ral R esources to attend as a gu es t sp eaker. M anu fa ctu rers of several on- site domestic sewage treatment system s were invited, as w ere Cou ncillors and staff R esidents visiting the displays and participating in the di scu ssio n numbe red close to on e

hundred . C hief Executive Officer Jim Nixo n repo rted to Co uncil that he would review existing plans w ith Peter Beavers. Later in the yea r the then D e partme n t o f Environm ent and H eritage (the departmen t respo nsible fo r issuing licences) advised Coun cil that the site was not sui table fo r the propo sed lagoons and spray irrigatio n treatme nt. In N ove m be r 1996 Council announced that it had received T erms of R eference fo r another environm en tal impact statem ent (EIS) for a sewage treatm ent plan t. T he site was made known in January 1997 . The availability of a $3 millio n interes t- free loa n throu gh the Smaller Com munities Assistance P rogram was announced and recomme nded to C ou ncil by the EIS consultant in March 1997. T he Shire's rate base is approximately SS million per annum and $900,000 of the loan is to be allocated to the pipeline. The site, upstream of D eepwater National Park, wo uld ca ter for both water supply and sewage treatm ent. C ouncil resolved to proceed with negotiations to purchase the 3,600 ha site. T he purchase was completed WATER JULY/ AUGUST 1998

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ENVIRONMENT

Round Hill Creek mangroves, an Important aquatic wlldllfe nursery area, could stlll be threatened by development

in August 1997. At the time of writing, in May 1998, the EIS has j ust been released for p ublic comment. Council has since created a compulsory rainwater storage tank policy for new approved structures and headworks charges have been adj usted accordingly. Another policy allows for bonding of headworks charges, i.e. a bank agrees to cover the headworks charges which the Council charges the developer to contribute to a sewage scheme. Both the Agnes Water Landcare Group and the D eepwater Creek Catchment Management Group, formed in 1996, became con cerned. Key issues are the purchase of land prior to the completion of the EIS, the absen ce of a consultation program and the revelation that treatment would take a similar form as planned for the first site, 1.e. lagoon treatment. Consi de ring the Natio nal Park down-

stream, the proposed site 'contain [s] the major and least distu rbed representation of coastal acid fres hwater wetland in Queensland ' according to the R egister of the National Estate D atabase Place Report for Deepwate r H olding. To dispose of wastewater to this ecologically important National Park is not acceptable to the comm uni ty. The perceived inadequate consideration of treatment options and their social, e nvironmental and economic impacts led the groups to contact the State Governmen t D epartments listed fo r consultation by Council in the Terms o f Reference. D uring formal discussions wi th Council representatives in D ecember 1997 a facilitated consultation program was requested, given the $15 million p roject budget. Council rejected this proposal, stating, 'We can't have our agenda hijacked.' However, a request

for an extension fro m one to three public meetings was agreed to by Council, whose invitation to put questions fo rward and have them answered brought to mind the 'cul-desac down which .ideas are lured and quietly strangled.' Believing that public participation is an integral component o f informed decision making and central to the planning process and that consultation is, as the Queensland M in ister fo r Local Government and Planning D i McCauley has called it, 'a de fi ned opportunity to influence the outcomes,' how else would this community have meaningful input into how their local com m unity develops? This is so, particularly given the limited and merely advisory process of Council. Because Council owns the land in fee simple, it is not necessa ry for the EIS to be released fo r public comment, as it would be for Crown Land. Jhanks to the D epartment o f Local Government and Planning, the appropriate process has been clarified , and Council has offered to make copies of the EIS available to the Agnes Water Library and concerned groups. T he Agnes Water and D eepwater C reek communi ties have received and are taking up the challenge of reviewing the EIS within 25 working days! We all await the subsequent departmental assessment process.

Author

Agnes Water Creek-at risk due to stormwater runoff

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WATER JULY/AUGUST 1998

Leonore Miller is a Community Resource Person w ho has been active in comm unity development for ten years, collaborating with many people to save parks, lobby for a sch ool, build a commu nity centre, found a lib rary and childcare centre and, especially, plan fo r the future.


BUSINESS

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MINING INTHE GREAT ARTESIAN BASIN P Bowman In October 1997 Pearce Bowman, Executive General Manager of Western Mining Corporation's Copper Uranium Division addressed the A WWA South Australian Branch Regional Conference. After a preamble abou t the challeng e ofglobalisation to industry and government, he expressed his support for the changes in tl1e South Australian water indust1y. H owever, he insisted that there should be adequate and transparent competition between potential private service providers during the tendering stage, followed by ongoing monitoring of service standards. EA (Bob) Swinton has prepared this edited version ofpart ofhis talk which dealt with the impact of the mine on the Great Artesian Basin. The Vital Component-Water In the driest state of the driest inhabi ted continent, many ways have been fo und to turn barren land into productive landholdings. Western Mini ng Corporation is doing that at the $1.5 billion O lympic Dam mine and plant, curren tly th e largest private capital development project under way in Australia. T he project is situated in an extremely dry and remote region where both the mine and the township of Roxby Downs are de pendent o n a secure water supply. Water is drawn from the G reat Artesian Basin at distances of up to 200 kilometres and piped underground. I stress that the bore fields have been strategically placed to harvest water which would otherwise be lost by vertical leakage and evaporation. Computer modelling of the resource has taken into consideration vertical leakage, spring flows and abstraction by other users to ensure sustainability. Barefield A has been in use since copper and uranium production began 111 1988, and currently supp lies up to 6 ML/d . Barefield B was commissioned in 1996, and supplies the balance of our current requiremen t, about 17 M L/d . The salinity of the water ranges from 1,000 to 5,000 mg/L. T he investment in the borefields, the pipelines and the desalination plant for potable water for the 3,000 inhabitants ofRoxby Downs is about $100 million, and the cost of raw process water is estimated at S 1.6 / kL, or about twice that of Adelaide's reticulated supply.

Expansion Subject to enviro nmental app rovals, ou r plans are to increase our annual production of copper from our current rate of85,000 tonnes to 200,000 tonnes

by 1999 so that water supply will be an even more significan t fac tor. The re is a strong incentive to minimise our use of water in the plant. We have redu ced consumptio n pe r tonne milled from 2.1 kL in 1989/90 to 1.57 kL in 1995/96. This has been achieved by: • developing work practices to become more water-efficient • substi tuting lower quality recycled water w hen p racticable • modifying metallurgical processes. By continuing these programs we estimate that by 1999 we should have reduced consumption to 1.24 kL/ tonne.

Impact on the Great Artesian Basin In the early years of this century it is u n de niable t hat the Grea t Artesian Basin was over-utilised by the pastoral industry. Bores were sunk almost at random and water was allowed to flow freely into bore drains to such an extent that the artesian p ressu re has steadily fallen. As a result governmen t bore rehabilitation programs were instituted. D uring the last 20 years, in the South Australian section, 192 bores have been capped, with a saving of abou t 105 M L/d. Our environmental impact statement (EIS) predicts our water requirements in 1999 to be 33 .4 M L/ d, well below this figure. In fact, within cu rrent licensed limits, we should be able to increase our copper p roduction to some 350,000 tonnes/year. T he total water storage of the Great Artesian Basin is estimated to be 8,700 million M L. T he recharge and discharge rates fo r the South Australian portion are now estimated to be in equilibrium, at a rate of 425 ML/d. The current daily discharges include: • 190 M L vertical leakage to surface evaporation

• 1,320 M L flowi ng bores, mainly pastoral • 66 Ml natural di scha rge through mound springs • 22 M L as part of the oil and gas abstraction at the Cooper Basin. And, of course, our present 17 ML. Our original EIS, publish ed in 1982, ou tlined the strategy w hich we have followed. It predicted that there would be some reduction in discharges from the natural mound springs around the rim of the basin and the outcome has generally been as p redicted. Now that Barefield B has been commissioned, and sited further into the Great Artesian Basin, we anticipate an increase in the flow of these mound springs.

Environmental Impact of Mining As a mine which produces uranium as well as copper, we are subj ect to close public scru tiny. Apart from that, we have contracted to monito r the impact on the Great Artesian Basin and the mound springs, and report regularly to the South Australian Government. O ur staffjoin the hundreds of environmental scientists who work for the mining and petroleum industries-more than for any other industry. The current E IS p rocess is the third major public review of the Olympic Dam proj ect in less than 10 years and we consider that we are a responsible user of the water of the G reat Artesian Basin. Our water strategy is well managed , extensively monitored and sustainable, and supports an in dustry with an export income in excess of S600 million a year. We are part o f the tide towards a new century of opportunity and progress for South Australia and so is the re-organised water industry. We are not j ust treading water- we are managing t his vital bu t limited resource to secure the fu ture of our State. WATER JULY/AUGUST 1998

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II

BUSINESS

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GROUNDWATER POLLUTION CAN RIGHT MARKETS HELP? M D Young, R Evans T his paper has been summarised by E A (B ob) Swin ton from You ng and Evans' fi nal rep ort to the Land and W ater R esources R esearch and D evelopmen t Corporatio n (LWRRD C), Right Opportunity: Using Right Markets to Manage Diffuse · Groundwater Pollu tion , dated O c tober 1997 to which refere nce sho uld be made for details. Copies can be obtained from LWRRDC , PO Box 84 , Lyneham ACT 2602.

Abstract This stu dy was commissioned to identify the pote ntial of righ t-market mechanism s to co ntribute to the reduction of diffu se grou ndwater pollution. It defined a right- market mechanism as any legal arrange m en t that grants somebody a right to do so mething or transfer that right to someo ne else. A trad eab le irriga t ion lice n ce is one example. A licence to discharge waste is another. Any condi tion s co nstraining tra nsfer of that right m ust be prescribed in advance of any such transac tio n. Four des ktop case stud ies were conducted to evaluate the potential of such right- market mechanism s. Whilst the study did not promote right markets as a panacea fo r the control of pollution from diffu se sources, it did see them as a mechanism worthy of serious co nside ration by wa ter resource managers. In particu lar, th e study reco mmended that as Council of Australian Government (COAG) wa ter reforms are impleme nted no groundwate r u ser be given a secure groundwate r u se right that preclu des land and wate r use conditions being atta ched to it. When co nditions are attached to use rights groundwater pollutio n can be co ntrolled efficiently at its source.

Introduction The irreversibiliry of groundwater processes demands serious consideration of the needs for m anagem en t to en sure sustainabiliry of the reso urce. - ARM CA N Z , J996 44

WATER JU LY/ AUGUST 1 998

Diffuse groundwater pollution is an in trac table problem as yet unsolved by Australia's water ma nagers. This study was commissioned by the Land and W ater R eso urces R esearch and D evelopment C orporation to identify whe th er financial incentive sch em es co uld assist. The diffu se g rou n dwate r polluti on problems co nsidered includ ed: • nitrate and phosphate pollution • pesticide pollutio n fro m agricultural practice • groundwate r sali nisatio n due to agri cultu ral p ractice • bacteria and nitrate pollu tion from septic tanks • seawater in trusion . Applica tion of righ t- market mechanism s to diffu se groundwater poll ution is challenging because grou ndwa ter is hidden from sight, slow-moving, broad-scale and ofte n naturally contaminated. It is also a medium whe re pollutan ts accumulate and mismanagement ca n have irreversible con sequ en ces.

Right-market Options The study ide nti fied five types of right- m arke t mechani sms that could be u sefu l in managing grou nd water poll ution: • tradeable emission-right syst em s w here the total annual load enteri ng an aquifer is capped . Pollute rs are issued a right to a share o f this load. Trading is en cou raged. M aximum co ncen trations are set. Surrogate indica tors ca n be used to reduce m onitoring costs • emission-offset systems where development approval is conditional upon pollution redu ction else whe re. No developme nt is allowed to cause a ne t increase in th e pollu tion rate • treater-pays systems wh ere wa ter treatme n t plants an d ecosystem managers pay for pollution reduction activities elsew here in the ca tchm ent because this is more co st-effective than water treatment • polluter-pays systems w here polluters are fo rced to share the costs of groundwater treatn1.ent and protection in proportion to their contribution to the problem

• conditional groundw ater-use right systems w he re condi tions are attached to surface water and/or groundwa ter rights so that the p olluting activities are eithe r encouraged to m ove to less vu lnerable areas, discouraged , prohibited or p hased out. ·

International and National Experience R eview of in ternational and national exp erience suggests that while rightmarke t m echanisms have been used to control surface water pollution, they have rarely been used to con t rol groundwa ter pollution . Th ere is growing expe rie nce in Au stralia with the u se of right- marke t m echanism s to co ntrol surface water pollution. P rogress on t he H unte r R.i ver in N ew So u th Wales, the Murray- D arling Basin Salinity Strategy and Victoria's Nya h to B order Sali ni ty R eduction Schem e are all beginning to d emonstrate th e grea te r efficie ncies, equi ty and ca pacity of righ t- market mechanism s to help alleviate i ntractable diffuse pollution problem s. Expe rie nce ind ica tes th at ri ghtmarket m echanism s always need to be underpinned by regula tion s. T he introduction o f right-market me chanisms makes it easier to e nfo rce these regulation s and obtain local owne rship of them. Many people do not understand the diffe rence be tween rights, enti tlem ents and obligations. A right is som ething that can only be c hanged with your co nsent. Most right systems, however, recognise the need to change things as e ntitlem ents change. T hus, if you own a block of land the title defines where the bounda ry stops and n o- on e can change it without your consent. That constitu tes your right. However, your entitlement to build a house on that land or even to pull down an existing one can change th rough ti me. Your oligations are to obey the local buildi ng regulati o ns if yo u do obtain su ch penruss10n. In the case o f wa ter resources, a right such as a proportio nal share of the


BUSINESS quantity of water that can be sustainably used for consumptive purposes can be defined in perpetuity. Sometimes, however, as new information becomes available it is necessary to re-specify what that right entitles a person to do. There is a need to recognise that new technologies emerge and knowledge about the characteristics and limitations of an aquifer can change. Similarly, it can be necessary from time to time to c hange reporting requirements. In a well design ed system, rights are secure and careful attention i s given to th e processes used to ensure that periodic adjustments to entitlem ents and obligations are equitable.

time to time as climate, information and types of water use varies. When the share is a share of the water available fo r consumptive use, it is administratively easier to deal with over-allocation problems. Share systems guarantee that any change in wate r allocations will be on a pro rata basis. Unlike other systems wh ich invite arguments about which allocations should be protected, under a share system any reduction in each person's total allocation is proportional. There is no special treatment and no special considerations can enter into the equation. If the reduction is too severe and you want more water or you want to pollute more, you have to buy more rights from someone else.

The Potential At the most general level, the case studies show that right-market mechanisms have a place in the control and redu cti on of groundwate r pollution from d iffu se multiple- poin t sources . The three systems that offer the greatest potential are: • conditional use-right systems which have application anywhere there is licensed groundwater use, primarily, irrigation • emission- offset syste m s which have appli cation w hereve r developmen t controls are in place • treater-pays systems which have application wherever a water authority has to treat water before distributing it for human use or has co treat sewage before d isposing it into a water body. Tradeable-emission right systems are also identified as a m echanism with poten tial. However, in most cases these systems require the establi shment of new databases and are unlikely to obtain political acceptance.

Conditional Groundwater Useright Systems Conditional groundwater use-right systems have the greatest potential, as they can be linked to existing licensing systems which can and in some cases are being made transferable. It is possible to use a conven tional volumetri c or area allocation system to define each person's share of a groundwater resource. D efinition of the right as a fo rmal sha re makes the true intent of any allocation much more transparent. Any allocation granted as a result of that share may need to be changed for one of many reasons such as climate change_ and improvements in knowledge abou t the sustainable yield of an aquifer. By calling the right a 'share,' water users are clearly informed that changes in the actual quantity of water allocated to them may need to be varied from

Emission-offset Systems Emission-offset systems work primarily by requiring any person w ho wishes to undertake a potentially polluting activity or expand one that is already in place to first offset the likely impact on a groundwater body. For example, in an area where a person wishes to establish a sep tic tank, they may first have to arrange for one or more existing septic tanks to be removed. Experience in the United States of America indicates that such mechanisms can be used to gradually reduce groundwater pollution. This reduction is achieved by requ iring people to offset more poll ution th an they can be expected to contribute to the problem. When offset arrangements are applied to point sou rces of pollution, poll uters some times find that it is cheaper for them to pay for the cleanup of diffuse pollution sources rather than thei r own pollution.

Treater-pays Systems Trea ter-pays systems are u sually linked to an emission-offset mechanism. In their study th e authors separate treater-pays systems from offset systems because Australian wastewater treatment works are required to meet very high standards. In many cases the cost of removing the last trace of nitrate or phosphate from sewage every day can be prohibitive. Sometimes it will be c heaper for a wastewate r treatm en t works to pay someone else to remove poll utants rather than improve their own performance. In Geographe Bay,* for example, the Busselton Wastewater Treatment Plane is facing the choice of spending $4.5 million followed by an an nual main tenance cost of $0 .5 million p er

*

The Western Australian Government has decided to build the $4.3 M treatment plant at Geographe Bay.

annum or contributing S0.5 million per annum towards the cost of a program designed to reduce diffuse sources of nitrate and phosphate from agricultural land. This latter option would save the people of Busselton a capital cost of $4.5 million and remove more nitrates and phosphates from Geographe Bay than any investment in improving the treatment of their sewage. By contributing to a diffuse source reduction program , diffuse source pollution reduction is expected to be around 10-20%, while if a pla n t upgrade goes ahead water quality in Geographe Bay would improve only by between 1%-3%. Even though it may seem ethically wrong to pay others not to pollute, pragmatically all people in the region will be better off if money is spent on · reducing diffuse rather tha n pointsource pollu tion.

Tradeable-emission Right Systems One attraction of tradeable emissionright systems is their outcome focus, i.e. they focus on pollution reductio n and make polluters pay fo r the costs of implementing a grou ndwater pollution control program. Control is achieved by setting an ecological limit and leaving market forces to decide how to keep ernissions within this limit. Each emi tter has the choice of either reducing their own emissions or paying someone e lse to reduce them. Unde r a cradeable e mi ssion-right system those w ho reduce emissions are reimbursed for at least part of th e cost of doing so by those who do not. At Venus Bay, where one case study was conducted, there is an opportun ity to implement a tradeable emi ssion-right system to im prove grou ndwater quality. Effectively polluters would pay for the costs of reduci ng groundwater pollu tion from septic tanks. Tradeable-emission rights also have application to the control of dryland salinity. Under such a regime, all people wou ld be levied and those who agree to help lower a watertable by plan ti ng trees would be entitled to reimbu rsement from the pool of money crea ted by the levy. Such mechanisms would be best applied at the ca tchment or subcatchment level. T hey can also be used to control groundwater pollution from animal waste. It needs to be stressed, however, that in most cases it is necessary to first set up a database and monitoring system to establish control of pollution sources. Such arrangements can be prohibitively expensive and in some cases politically unacceptable. WATER JULY/AUGUST 1998

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BUSINESS Desktop Studies Because of the lack of experience both in Australia and overseas, a desktop study of four cases was conducted to evaluate the potential of right-ma rket mechanisms to reduce diffuse groundwater pollution. These cases were located at Wa n neroo Groundwater Area, Western Australia, the lower south-east region of South Australia, Venus Bay, Victoria and the Namoi Region, New South Wales.

Wanneroo Groundwater Area, Western Australia By 2010 , groundwater will contribute nearly 50% of the water supplied to Perth. The Wanneroo field north of Perth will be a maj or component. Potential pollutio n problems are nitrate and phosphate derived from fe rtiliser and manure and to a lesser extent from intensive animal industries. In some horticultural areas the ni trate level in groundwater is already on the drinking wate r limit of 10 mg/ L. C urrently the main control mechanism is to zone the p olluting activities away from the domestic abstraction fields. T he right-market optio ns identified were: • emission-offset-new pollu ters must ensure there is an equivalent reduction elsewhere. This places all the responsibili ty o n developers, and existing landholders obviously would regard this as very suitable • tradeable emission- right-each la ndholder is issued a share of the total nitrate budget and a complex tender system ensures that fertiliser and manure spreading remain within that share • conditional groundwater-use right rights to apply water for irrigatio n are constrained. The stu dy indicated that t he optimum would be the latter system, coupled with an emission- o ffset fo r new sources of pollution w hich do not use irrigation. Lower South-east of South Australia T he shallow unconfined aquifers in this region are used both for drinking water and the irrigation of pastures, vineyard s and h orticulture and t he aquifer is extensively recycled. Current nitrate pollution results in 3% of bores are above ANZECC standards for adults, and 15% are above safe limits for infants. In some areas, salinity is rising at 50 mg/L per year. (Some excellent wine does not comply wi th EEC and Australian standards for free sodium!) No meters are used, so the groundwater allocation is based on 'irrigation equivalents,' or the right to irrigate an area of crop whose water needs are equivalent to one hectare of pasture. 46

WATER JULY/AUGUST 1998

The current most profitable crop is vines irrigated with slightly saline water. At the same time, there is a move to increase the area under pine plantations, which may produce absolute shortages of groundwater. The right- market options are: • conversion of current allocations into shares, subject to conditions to reduce groundwater recycling. Management plans would reward those w ho improve water use efficiency • an annual zero- tender system requiring each landholder to place, say, 5% of shares up for sale, with a set reserve price . This would force people to recognise that irrigation rights are transfe rable, reveal the value of water to all and encourage people to buy and sell irrigation rights • tradeable- emission rights fo r anticipated down- flows of n itrate to the aquifer. This can easily be converted to a conditional irrigation- right system • inclusion o f pine plantations into water allocations by requ iring new plan tation owners to acquire irrigation rights equ ivalen t to the amount of recharge reduced by the trees they establish. Existing plantation owners would have thei r prior rights formally recognised. A mix of the options varying in differe nt zones is likely to be the most effective.

Venus Bay, Victoria Venus Bay is a holiday town on the South Gippsland coast. T he permanent population i s 120 and the summer population about 3000. Most of the 512 houses have septic tanks, relatively close to the bores used for domestic supplies. Movement of nitrate and bacteria to the sedimentary aquifer is rapid and the groundwater is already highly contaminated and unsui table fo r in- house consumption. The options are to install a sewage system at a cost of $8- 16 million, a communal pump-out scheme or comm unal septic tanks at a cost of$650,000 or to introduce financial incentives that gradually achieve separation of the septic tanks from the bores by 15-30 metres so that bacterial pollution is reduced. To achieve separation, the options would be: • emissio n- offset-to cap the nu mber o f septic tanks and require all new houses either not to use tanks or to remove at least two existing tanks for each new one they install. All new tanks would be at least 30 m from a bore. Bores could eventually be decommissioned, as there is a strong market incentive to move to a pump-out or comm unal septic tank system. T hose who 'upgrade' would receive a paymen t of between $1,500- $2,500 fro m a pool

established via a levy on those who choose to retain their current septic tank. However, even if the housing stock grew at 2 .5% per annum it would take nearly 10 years to reduce the number of tanks by 20%, groundwater quality would not reach acceptable levels before 2020 and local 'hot spots' would remain • tradeable sewage emission- rightshares initially issued in inverse proportion to the separation distance from a bore. Pe riodic revisions of the plan would require an increased numb er of shares for permission to instal a tank at a shorter separation distance. A zerorevenue tender would be used to speed adjustments. Those w ith insufficient shares must either leave their house unoccupied, or pay 20% above market value for the requisite shares. T he cost to the community to achieve acceptable groundwate r quality is estimated at around $523,000 • a quasi-tradeable e mission- righ t non- complying houses pay a levy sufficient to pay $3,500 to each household that upgrades to the 30 m separation distance within two years and $2,500 for later upgrades: It is estimated that this scheme would cost $680,000. Whilst not a right-market option , a fourt h option would be to fo rce the entire town to convert to a pump- out scheme, with ann ual operating costs. Each of the three right- market schemes is significantly cheaper fo r a holiday town . The third system is easiest to implemen t, and when adm inistrative costs are factored in , may be the most cost-effective.

Namoi Region, New South Wales In this region both surface water and groundwater are extensively used for agri culture, and despit e volum etric controls since 1985 the groundwater level is declin ing. From a te tal of 62 samples collected from sh allow aquifers in 1992-3, five recorded detectable levels o f atrazine. T he highest level was 5 µ g/L. Another diffuse pollution issue is migratio n of saline groundwater . In some bores, TDS has risen fro m 400 to 800 and even 1,200 mg/ L. In this case study there is virtually no right- market mechanism w hich would alleviate the pestici de problem. T o tackle the salini ty problem, groun dwater allocatio n s i n problem areas would have to be reduced. The main right-market option would be to secure groundwater shares with entitlements and associated obligations w hich would be periodically reviewed. On a separate issue in the catchment of dryland salinity, a levy on all landh olders to reimburse others engaged in tree plan ting and other schemes is proposed.


BUSINESS Extent of Specific Problems and Assessment of Potential

able to irrigation, the authors recommend that in areas where there is over-allocation Diffuse pollution problem Percentage of problem or overuse of an aquifer, area amenable consideration be given to the The geographic extent and merits of including forms of Nitrates economic importance of difExcess fertiliser applications landuse like timber planta30 fuse groundwater pollution 20 Animal excreta tions and deep- rooted perenacross Australia has not been Legume pasture 10 nial pastures within the allocaPesticides 1 defined. Documented examtion system. ples therefore tend to be Groundwater salinisation They recommend that all sporadic and anecdotal. Land clearing 40 groundwater allocation sysRecycli ng 75 Moreover, the extent of tems be designed so that at a Lateral migration 75 reporting and monitoring of later stage it will be possible to Irrigation 50 diffuse groundwater pollution vary annual allocations as Bacteria, nitrates from septic tanks 50 in Australia's states and terrirainfall, recha rge rates and Seawater intrusion 90 tories is as yet only modest. environmental considerations * Subjective assessment only Because the scale of the change. problem is not well underA further recommendation stood, any assessment of the ability of have to pay to remove nitrates from is that consideration be given to the right markets to deal with non-point grou ndwater. H oweve r, t he au thors introduction of share-based allocation sources of pollution m ust be highly cannot see them making a significant systems that give each licensed ground- . contribution to the control of nitrate water user a fo rmal share of the amount subjective. W ith these caveats, and assuming pollution from non-irrigated pasture or of water available in an aquifer for consumptive use. Such an arrangement state government willi ngness to use livestock grazing. D espite setting out to fi nd a means of would give each user a guaranteed right right markets to control diffuse groundusing right markets to control nitrate to use groundwater sustainably but at water pollution, the authors have made a subj ective assessment of the potential pollution from unirrigated legume the same time provide periodic opporof right m arkets to make a significant pastures and pesticide pollution of tunity to review and improve definition contribution to the extent and intensity groundwater, the authors found no case o f the e n ti tl em ents, co nditions and of diffuse groundwater pollution in where these problems are sufficiently obligations that attach to that right. severe to j ustify the use of right markets Offset mechanisms would be used as an Austral ia. This assessme n t is sumto achieve this end. This does not mean interim measu re to control reduction of marised in Table 1. recharge from areas placed under The conclusion is that right-market these types of pollution are not going to plantations. become a problem , but only that they mechanisms have only a very small With regard to the reduction of scope to control diffuse groundwater are not yet a problem. As salinity diffu se pollution from m ultiple-point problems are ofte n associated with pollu tion due to pesticides, a moderate groundwater use, the authors see this sources, like septic tank installations ability in the case of ni trates, and a high mechanism as a powerful means to which are linked to development ability in the case of groundwater salinapprovals, they recommend that offset address this problem. isatio n and seawater intrusion. mechanisms be u sed as a means to Because no examples of se riou s Conclusion prevent increases in the flow of nutridiffu se pesticide groundwater pollution ents to groundwater and where approThroughout the course of this study were found , the assessment of the priate reduce the flow of these nu trients the authors were continually asked for to groundwater. applicability of right markets to control more information on the steps necesIn view of the high cost of removing pesticide pollution may be wrong. sary to implement each of the options nutrients from groundwater sources in Pragmatically, the authors observe identified in thi s report. These are some locations and the relatively low that right-market mechanism s have reported in detail in their final report. cost of achieving much greater rates of much wider public acceptance in the As a result of the range of case studies control of pollutants whic h occur and exp erience analysed, the authors improvement from diffu se sources, the naturally in groundwater. In their conclude that right-market mechanisms authors recomm end t hat state and judgement licensing people to place are best suited to the managem ent of federal agencies encourage water treatment authorities to become involved in 'approved' quantities o f pesticide in contaminants that are naturally present programs that reduce the flow of nutrigroundwater is likely to be politically in aquifers. Nitrates, phosphates, and ents to groundwater in the most costunacceptable. They therefore see little salt clearly fall into this category. Where effective manner possible. potential fo r the use of right-market a community aspires to near-zero Finally, the authors recommend that mechanisms to control pollutants that contamination levels, a strong regula- their report be referred to the COAG are no t naturally present in an aquifer. tory approach is likely to be more Task Force on Water R eform for Across Australia the highest priority effective. con si deration of t he advantages of diffuse groundwater pollution problem In conclusion, they recommend that designing water allocation systems that is probably nitrate pollution. H ence, no groundwater user be given a secure encourage water users to reduce even w ith only an assessed moderate groundwater use right that precludes groundwater pollution. applicability, the use of right markets to the attachment of land and water use control this type of pollution is worthy conditions to that right and does not Authors facilitate the periodic review of the of serious consideration. Mike Young is an Ecological EcoRight markets are easily used to entitlements, conditions and obliga- nomist with CSIRO Land and Water, tions that attach to that right. reduce nitrate pollution in irrigation PMB 2, Glen Osmond SA 5064. Rick areas and have proved powerful in areas With regard to the effects of landuse Evans is Principal H ydrogeologist with where animal manure sp reading is change on the amount of groundwater Sinclair Knight Merz, 590 Orrong common and in areas where people recharge and hence the amount avail- Road, Armadale, Vic 3143. Table 1 Applicability of right-market mechanisms to reduce non-point source groundwater pollution in Australia*

WATER JULY/AUGUST 1998

47

Profile for australianwater

Water Journal July - August 1998  

Water Journal July - August 1998