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DECEMBER 1987 JOURNAL OF THE AUSTRALIAN WATER AND WASTEWATER ASSOCIATION


EXECUTIVE DIRECTOR P. Hughes Box A232 Sydney South 2000 (02) 269 6814

FEDERAL PRESIDENT M. Dureau , Kent Inst rumen ts P/L P.O. Bo x 333, Caringbah 2229 (02) 525 28 11 .

water

ISSN 0310-0367

Off icial Journal AUSTRALIAN WATER AND WASTEWATER ASSOCIATION

Vol. 14, No. 4, December 1987

FEDERAL SECRETARY G. Cawston Box A232 P.O. Sydney Sth., 2000. (02) 269 6157

FEDERAL TREASURER J . D. Molloy, Cl- M.M .B.W. 625 Lt . Collins St ., Me lbourn e, 3000. (03) 615 5991

BRANCH SECRETARIES Canberra, A.C .T. M. Sharpin , Willing & Part ., . P.O. Bo x 170, Curlin, A.C.T. 2605. (062) 815 811

CONTENTS Viewpoint .... ....... .... . .. .. ..... . .............. . . . ....... .

5

Association News, Views and Comments . ............ .. ... . ..... .

6

Environmental Effect of Canal Estates in Australia -P. M. Nuttal and 8. J. Richardson . ........................ .

14

The Dirty Dollar and How it's Laundered -J. G. Parker and B. J. Lyons . ... ... ....................... .

18

Setting Priorities for R & D in the Water Sector -Dr Peter Nadebaum for the A WWA

23

National Water Research Seminar Canberra-September 1987 -Dr P. R. Nadebaum . ............ . . ...... ............. . .. .

25

Polyelectrolyte in Sludge Conditioning Use of Rheology for Control - T. R. Bridle and C. K. Hertle . ...... . .............. ........ .

27

IA WPRC News . ... ... .. ............................ ... ...... .

28

Towards Affordable and Effective Water Treatment -A. G. Strom and J. A. Crockett

30

The Quality of Water is not Strained - J. R. L. Forsyth ... . ............ . ..... .. . .. ...... .. ..... .

34

Water Quality Management in Victoria -R. A. Graham and R. G. Peck . .............. .. ............ .

4()

Book Reviews ... .. .... ..... .... .. . . ........ .... .. . ... ....... .

44

People & Company News ............. . ....................... .

46

Products • Plant • Equipment .......... ... .......... .. ......... .

47

New South Wa les Mrs S. Tonki n-Hill , Sinclair Knight & Part. 1 Chandu s St. , St . Leonards, 2065, (02) 436 7166

Victoria J . Park, Water Training Centre, P.O. Box 409, Werribee, 3030. (03) 741 6844

Queensland D. Mackay , P.O. Box 41 2, We st End 4101. (07) 844 3766)

South Australia R. Town se nd, State Water Laboratories, E. & W.S. Private Mail Bag , Salisbury, 5108. (08) 259 0316

Western Australia Mr K. Cadee , Wat er Aulh. of W.A. , P.O. Box 100, Leedervill e 6007 (09) 420 2457

Tasman ia G. Nolan , G.P.O . Box 78A, Hobart 7001 (002) 44 0600

Northern Territory P. Abbey, P.O. Box 37283 Winnellie, N.T. 5789. (089) 89 7290

EDITOR IAL & SUBSCR IPTION CORRESPONDENCE G. R. Goffln , 7 Moss man Dr., Eaglemont 3084 03 459 4346

COVER PICTURE The newly constructed Bank-note Printing Works of the Reserve Bank.at Craigieburn on the northern outskirts of Melbourne ,which involved a unique and complex waste-disposal problem. WSL Consultants Pty Ltd of Melbourne performed the necessary investigations and designed the requisite treatment plant which is constructed partly ins ide the building and partly externally, at a capital cost of $1.5 m. The investigation, process design and monitoring of the operating plant are described in this issue, pages 18-20. Front cover donated by WSL Consultants Pty Ltd.

The statements made or opinions expressed in 'Water' do not necessarily re flect the views of th e Australian Water and Wa stewa ter Association, its Council or co mm ittees.


Environmental Effect of Canal Estates in Australia P. M. Nuttall and B. J. Richardson ABSTRACT Canal estate development in Australia has created over 200 artificial waterways throughout Western Australia, New South Wales, Victoria and Queensland. Construction began in the subtropics during the 'fifties' as a means of extending the limited water frontage available for real estate development. However, canals almost invariably exhibit problems with water quality, biology or hydraulics, not only in the water channels but also within the parent water body. This paper reviews the environmental effects already experienced in canal estate developments in Australia.

INTRODUCTION Canal estates were introduced to Australia during the mid-l 950s with the intention of extending the limited area of tidal waterfront land available for residential development. The first of these artificial waterways was constructed on the Nerang River in Queensland's Gold Coast. Since 1960, residential canals in Australia have proliferated rapidly. In the eastern sub-tropical region alone there are now over 200 completed developments with major canal systems at Southport and Mooloolaba. At least 45 residential tidal canals have been developed in New South Wales, with the majority situated in the northern sub-tropical zone and built in the 1970s. A number are still under construction or are incomplete. In Western Australia, construction of residential canal estates has been limited to the Peel-Harvey inlet. In Victoria there are a number of developments, under construction and proposed, located around Port Phillip Bay and in the Gippsland Lakes. Although these developments differ in the nature of the waterbodies on which they are built, all have a common design feature of providing private residences adjacent to a tidal waterway with space for private boat moorings, ramps or jetties . The main channels most commonly branch into closed-end canals, although an increasing number of estates are designed as flow-through with access to open seas, estuary or bay through two or more openings.

Mr. Peter M. Nuttall, B.Sc.(Hons.), M.Sc., M.I. Biol. is Research Biologist for the Dandenong Valley Authority and is presently completing a Ph.D. through Deakin University on the environmental effects of canal estates in Victoria. He has many years experience in pollution control studies and in the field of environmental management. Dr. Bruce J. Richardson, Dip. Tchg., B.Sc.(Hons), Ph.D., is Lecturer in Microbiology in the Division of Biological and Health Sciences at Deakin University, Geelong, Victoria. His research interests include the use of living organisms as monitors of environmental contamination. He has been particularly involved in monitoring polychlorinated biphenyl (PCB) contamination in the Australian environment. Loss of mudflats and alteration in the tidal prism, was caused by dredge-and-fill operations for canal estates on Brisbane Waters, N.S.W. The area was an important feeding ground for waders which have decreased in both numbers and diversity since development began in the early 1970s. A comparable situation could result from the second stage of the Waterside Mandurah estates under construction on the Peel-Harvey inlet, south of Perth, where the loss of mudflat!!; would drastically alter the invertebrate food base for trans-equatorial migratory waders.

LOSS OF COAST AL RESOURCES Canals are invariably built in low-lying, unprepossessing areas associated with estuarine mudflats or sand beds, coastal wetlands, saltmarsh-mangrove and ti-tree communities or shallow, saline lagoons (Figure 1). As a result of this there has been increasing . concern expressed over the effects of such developments on the coastal environment. In New South Wales, for example, many estuaries and wetlands have been damaged through the effects of dredging and reclamation as a result of indiscriminate or ill-planned developments (Middleton et al., 1984). Pointless destruction of mangroves was done by the now aborted construction of the Wandering Star canal project at Yamba. Mangrove and marsh plants, along with seagrass, are vital to estuary life. Each square metre of mangrove forest contributes an average 1 kg a year of organic matter to the food chain that supports most of the species sought after by commercial fishermen. Studies by Ellway and Heger! (1972) showed that dredging on the Tweed River at Coolangatta accounted for the loss of 11 fish species from the estuary. This, and a rapid decline in the total numbers of other fish species, was primarily the result of smothering by silt from the dredging of small aquatic animals eaten by the fish. About 600Jo of the commercial fish species in the total New South Wales catch are dependent on estuarine habitats at some stage in their lifecycle (Pollard, 1976) and the Australian oyster industry, currently undergoing rapid expansion is conducted in and wholly reliant on closed coastal waters. 14

WATER December, 1987

V Figure 1. Location of completed tidal canal estates in Australia (each circle represents 1 or more developments).

WATER MOVEMENT IN CANALS Because of hydraulic problems experienced with many tidal canals constructed elsewhere in the world, attention has been focused in Australia on circulation and exchange of canal water with the parent water-body. In engineering evaluations, it has been common practice to attribute water renewal in residential


canals to tidal currents and tide-induced m1X1ng. However, in closed-end canals greater than an arbitrary 5 km in length most water replacement comes from radiation induced density chang~s or wind-induced movement. This is particularly so where the tidal range is so weak as to be ineffective as a flu shing mechanism , for example in ca nal estates under constru ctio n on the Gippsland Lakes, Victoria. Wind-induced move ment of wa ter is substantially restricted by house constru ction and fences alongside water channels and the growth of pla nted trees in gard ens even where canal widths are greater than th e ge neral minimum of 45 metres (Figure 2) . Weak circulation also res ul ts from stratification with less dense freshwater runoff sitting on top of saltwater and restricting density-induced move ment to the surface layers. Stratification may persist for severa l wee ks causing oxyge n depletion below the stratified water.

FLOODING Canal developments are often sited in flo od-plains which are subj ect to peri odic floodin g. Filling to above flo od levels do es not necessarily affect fl ood capaci ty, providing adequate fl oodways are retained . Ho wever , ma ny Australian canal estates are on river mouths where land obstru ction to water passage increases the potential for flooding du ring storms. Kawa na Waters is built on the mou th of the Moo loolah River on the Sunshine Coas t where rainfa ll is aro und 250 cm a year. Risk of floodin g is increased by the removal of catchment vegetation which would normall y retard storm water runoff enterin g the river . Predi ctions of global warm ing and relative changes in rainfall and in the sea level of at least 0.2- 1.4 metres by the next decade must increase the hazard of fl ooding fo r the majority o f canal estates around the A ustralian coastline.

GROUNDWATER CHANGES

>

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50 .. ..

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' •

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0 9.IX.86

D

26.IX.86

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OPEN WATER

Canal estate development can alter gro und water reso urces by influencing the mo vement of phreatic water or by dim inishing bore water supplies through overuse by residents. A superficial aquife r underlying coastal Wes tern A ustralia was drawn on by established residents using pri vate bo res, mostly fo r gard en irrigation , even though a reticulated water supp ly was availab le. Subsequent dewatering fo r canal estate constru ction in the area fo llowed by intensifi ed demands upon the aquifer by the increasing number of households fro m canal developments is believed to have caused an undesirable shift in the saltwaterfreshwater interface . It was recommended that the EPA should advise residents that continuing supplies o f ground wa ter could not be guaranteed and that furth er drawing on the aqu ife r was undesirable.

j:::;:::j TIDAL C ANALS WATER QUALITY Figure 2. Wind velocity at water surface level in develo ping canals (o pen water) and mature canal estates.

The Yunderup canals in Wes tern Austra lia exhibi t mar ked stratification during January and July res ulting in a 5007o oxygen sag in layered water (B rindley, 1984) . Flushing is so poor at Yunderup that for ced circulation has been suggested as a remedy fo r stagnation problems. A t other times of the yea r radiant heat penetrates to the bottom layers o f stratified water which in turn become heated and reach a higher temperature than the surface layers. T his solar pond phenomenon has also been observed in canal estates at P atterson La kes, Victoria (Nuttall , 1987). In Queensland , stratification is generally not a prob lem in canals of minimum depth (2 m below chart datum) although hypoxia has been recorded in some deeper canals and there are some reports of a noxia combined with a thermocline-halocline in deep canals of small tidal range .

TIDAL FLUSHING Increasing the num ber o f turns of canals, creating islands and obstru ctions such as bridge abutments and flo odwater barriers reta rds water flo w. In suffi cient tidal exchange contributes to stag nation in many of the backwa ter canals on the Tweed Rive r where the long lead channel res ults in poor mixing. Detention periods in canal estates on the Nerang and Mooloolah Rivers vary fr om 36 h to about 1 month . Moss (1 982) notes that deep water deoxygenation can be significant at the upper ends o f extensive canal systems on the Ne rang River. In some Queensland canals there is intentional red uction of tidal influ ence . At Bribie Gardens the mean tidal ra nge of 2 m is redu ced to a tenth to fac ilitate boat mooring by gates across the canal entrance. Residential canals increase the volume and velocity of water to the parent water-body at ebb and fl ood tides, altering esta blished flow and circulatio n patterns. T he tidal vo lu me of the Nerang Rive r has been increased by two th irds because of canal development, resulting in excessive tidal velocities in the canals and estuary. A single open ing to the Patterson Lakes tidal canals south o f Melbourne is being duplicated at a cost of $1.2 million to allevia te boat nav igati on difficulties throu gh the entrance caused by high water velocity fr o m continuing canal construction .

Water quality in canal estates not only depends upon the configuration and dimension of channels, on the quality o f th e parent water- body and on the tida l range but als,o on biological and physiochemical processes whic h go on in the canals and on the nature a nd fre quency of envi ronmental stress which might occur . Weak circula tion or insufficient tidal exchange in closed-end canals periodi cally leads to substa ndird water quali ty characterised by defi cient oxygen levels and blooms of algae. Algal res pi ration at night , decompositio n o f dead algae and the breakdown of orga nic matter within the sediments contributes to increased oxygen depletion in the wate rways . Sediments which become anoxic during summer in th e Murray Lakes and Windslee canal estates, Wes tern Australia, are the res ult of poor flu shing and water mo vement combined with high nutrient levels entering from the Mur ray River (Lukatelich and McComb , 1983) . If marin e sediments remain anoxic for long enough, hydrogen sulphide is produ ced by sulphate- redu cing bac teria which then combines with iron oxides to fo rm the blac k, anaero bic hydrotroili te and fe tid-smelling disulp hydry l iro n muds. Hydroge n sulphide and other noxio us gases can be brought to the sur face on occasions when the water becomes mixed and can cause pro blems to residents who lived beside the cana ls. Fish kills, od our and discolouration have occurred on the Neran g River estates fo llowing autumn turnover . An add ed cause o f oxygen depletion in some Q ueensland canal developments may be run off containing organic peat fro m the Wallum heath swamps which were drained and excavated fo r canal constru ction (Wes tman, 1975).

POLLUTION O rganic pollution fr om septic ta nk discharges to waterways has prompted pu blic complaints a t Sylvania Wa ters, N .S. W ., Yunderu p, W .A ., Florida Gardens a nd other canal developments on the Gold Coast. A number o f Queensland canals initiall y had efflu ent entering soa kage trenches and pits which fo un d its way into canals. Highl y va riable soils may cause engineering problems if the soil is inadeq ua te as fi ll material. Fractures a nd leaks fr om sewerage lines have happened on a num ber of canal estates caused by di ffere ntial settlement of reclaimed land . Urb an run off en tering canal systems fr om road drains contributes a substantial portion of organic and inorga nic con taminants to wa terways. In some cases, provision has been made WATER December, 198 7

15


to either divert or detain urban runoff. For example, pipe outlets are screened and drainage lines directed away from closed-end canals on Patterson Lakes canal estates, Victoria. Enrichment from the excessive application ¡ of garden fertiliser, from hydromulching during the final stage of canal development and from the release of human waste from boats and marinas appears to be common to many canal estates. Release of pollutants such as oil and petrol from boat fuelling facilities and the leaching of heavy metals from boat antifouling paint is associated with marinas located within or at the entrance to canal estates. Polycyclic aromatic hydrocarbons have been found concentrated at boat marinas on canal estates in Victoria (Nuttall, 1987). In many cases, water quality in closed-end canals proves to be inferior to the parent water-body, resulting in a fall in standards such as turbidity, suspended-solids and chlorophyll-a during ebb tides. Canals constructed on river mouths are vulnerable to catchment runoff, particularly in urbanised or industrialised areas where various biodegradable and non-degradable pollutants enter the water. Even where low flow river diversion is undertaken to protect water quality standards on canal estates (for example Dandenong Creek is diverted from the Patterson Lakes estuary developments on Port Phillip Bay) flood flows carrying a significant amount of pollutants in the first flush enter the original course of the river.

A

10.11.86 2m 20m

A

16.1.87

mobile silt

SEDIMENTATION On-site runoff during heavy rain or aerial fall during hot, dry winds causes silt and clay from canal construction to enter the parent water-body and other completed waterways. Stormwater runoff, particularly from developing catchments, carries large amounts of inorganic and organic particles which wash into the estuary and settle out in the slack water of canal estates (Figure 3). 1986

1987

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,

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1975

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19861

19861 ,

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_ _ _ _ _ _ _ _ closed-end canals _________ estuary _______________ entrance to canals Figure 3. Water clarity in Patterson Lakes canal estates, Victoria (measured over a 16 month period using a Secchi-disc).

The result is that bottom sediments in canal estates have an increased silt and clay content when compared with the parent water-body. Bottom sediments collected from McMillan Strait, Gippsland Lakes contained a higher percentage of coarse material such as sand and shell than sediments from the Riviera Harbours canals estates being developed on the strait. At times, runoff from Riviera Harbours carried a plume of turbid material into McMillan Strait which eventually settled on the coarser sediments causing a localised but measurable increase in the silt-clay fraction. There are several important environmental effects from this sedimentation pattern. Firstly, tidal canals undergo profile changes caused by the deposition of suspended solids (Figure 4). The problem is intensified by boat movement reworking and redistributing loose, unstable sediments and by the erosion of beaches by anglers using sand pumps to collect bait. Organisations who are responsible for maintaining the waterways as navigable channels usually respond to this problem with suction or mechanical dredging , even though it is accepted that this affects the ecological stability of aquatic organisms. Suction dredging on the Nerang River canal estates resulted in a marked influx 16

WATER December, 1987

B

t 1975

~c

Figure 4. Changes in canal profile at Patterson Lakes estates, Victoria at three sites over 1 year (Site A) and 10 years (Sites B and C).

of opportunistic species ab le to utilize areas of freshly-exposed sediments to the disadvantage of the established fauna (Saenger and Mclvor, 1975). Also, benthos initially adapted to living in coarse sediments of the parent water-body, may find difficulty colonising the fine-textured material of tidal canals. Turbid water restricts light penetration for submergent aquatic plant photosynthesis with a consequent reduction in habitat diversity and food supply for estuarine animals . Organisms living in or on the bottom of canals are smothered by the deposition of finegrained particles which also fill up the interstices between coarser material. This not only affects the cryptic fauna and flora but results in higher temperatures and oxygen depletion within the sediments because of the reduction in pore space. Pollutants brought downstream in catchment runoff readily bind to clay particles, flocculate in saltwater and settle on the canal bottom. Bioturbation can return the pollutants to the sediment surface from underlying layers where they are available for biotic uptake or re-entry to the water column.

BIOLOGICAL PROBLEMS Biting midges (Culicoides spp.) have become a problem on intertidal beaches of canal estates in the subtropical zone of New South Wales and Queensland. Often misnamed sand flies, biting midges are pests of both people and livestock. The species C. moles/us has assumed major pest status on residential canals and is found on all beaches which extend up from mean tide level


(Reye, 1982). The egg-adult cycle is about 16 weeks and in the subtropics the build-up of population to pest level takes about two years. Larvae of Culicoides sp. have also recently been found in canal estates in Victoria where waterside residents have occa 0 sionally complained of skin irritations and bites. The Gold Coast Council has adopted a larvicidal programme against the infestation , spraying with a particulate susper\sion of deltamethrin. The insecticide Abate has also been used to control biting midges on Queensland 's canal estates. However, the only lasting preventative measure is to ensure that the beach does not extend above mean tide level and this policy has been adopted at Ocean Grove , Brunswick Heads, where submerged slopes have been incorporated into canal design. Breeding of mosquito where conditions are suitable in closedend canals, amongst mangrove and riverine marshes in Queensland and in coastal wetlands around the Peel-Harvey estates in Western Australia is a problem to waterside residents. Apart from disrupting the outdoor life style which canal developments promote , mosquitoes transmit various diseases which are not necessarily confined to zoo-geographical boundaries. The species Aedes camphorinctus identified as larvae from closed-end canals in coastal Victoria has been implicatec;l as the vector for Ross River fever virus into the Gippsland area in 1986. -In a number of estates, attempts to overcome circulation problems in closed-end canals using interconnecting pipelines have been fr ustrated by biological growth . At Forster Keys, N .S. W., water flow through 850 mm pipelines became seriously restricted by growth of the tubeworm Galaeolaria sp . and at Patterson Lakes, Victoria, the tubeworm Mercierella enigmatica colonised interconnecting pipelines at the rate of 600 g dry wt/sq .m. over a six month period. The problem is not only confined to pipelines, for in Patterson Lakes tubeworm successfully colonise most vertical hard substrata in the intertidal zone including revetment walls, jetty piers and bridge supports. When the basal secretion of the tubeworm is unable to further support the weight of calcareous growth or earlier if it is deliberately broken off, the entire mass fa lls down to form an underwater reef capab le of damaging boats. Marine foulin g organisms such as barnacles, mussels, serpulid worms and macroalgae tend to be more abundant in the enclosed areas of canal estates where currents transport considerable amounts of detritus. Encrustation by mussels and serpulid worms may prevent the closure of flood gates . Organic enrichment from sewage or the discharge of sullage from town drains into closedend canals causes intense development of the fouling green algae Enteromorpha and Ulva. In summer when these growths are excessive they may be thrown up in large amounts at the high water mark to decompose on canal beaches, giving rise to hydrogen sulphide and attracting large numbers of flies.

Assessment Act 1979. An environmental impact assessment (EIA) is required as part of the approval process ~ t local, regional and state levels. In Victoria the approval process for canal developments comes under the Planning and Environment Act 1987 (not yet proclaimed). An environmental effects statement (EES) is not necessarily required although it may be imposed at the discretion of the Minister for Planning and Environment. In Queensland, the construction of canal estates is regulated by the Canals Act 1958 to 1984. Although local authorities have been given statutory provision for environment impact assessment (EIA) procedures through the Local Government Act, few seem to have developed policies giving this effect. Western Australia has specific guidelines for proposed canal estate developments (Steering Committee on Canal Development , 1984). Acceptance of an impact assessment document termed Environmental Review and Management Programme (ERMP) is a necessary precursor to development. This pi;pgramme includes a requirement for on-going monitoring and research as the development proceeds . Inconsistency between the various states over environmental impact assessment of canal estates reflects differing political attit udes and environmental val ues. All states require some form of EIS for canal developments on their coastline. The Commonweath, in certain situations, has the power to require an EIS itself under the Environment Protection Act (Impact of Proposals) 1974.

REFERENCES BR INDLEY, R. F . ( 1984). ' Ph ysical Water Qualit y Data in Yunderup Canals, Western Au stralia'. Peel IQlet Management Authority, Western Australia, 56 pp. ELLWAY, C. P. and H EGERL, E . J. (1972). Fishes of the Tweed Rive r Estuary, Operculum 2( 1): 16-23. LUKATELICH , R. J. and McCOMB , A. J. (1983). ' Water Quali ty Mo nit orin g Programme in the Murray River' . Waterways Commission, Peel Inlet Management Authority, Report No. 3. MIDDLETON , M., AL LA N, G. a nd W ILLIAMS, R. (1984). G uidelines for Canal Estate Development. Advisory Note No. 3/ 84, Department Ag riculture, Syd ney, N.S.W., 4 pp. MOSS , A. J. (1982). Behavio ur . of some Residential Waterways in Queensland. In ' Water quality aspec ts of residential waterway de velopments' , p. 16-33. Semina r, August, 1982 , Queensland Branch, A .W.W.A. NUTTALL, P . M. (1987). Environmental J;,ffects of Residential Tidal Canal Developments. Ph .D. Thesis. Deak in Uni ve rsity, Vic. (in preparation). POLLARD , D . A . (1976). Estua ries must be Protected. A ustralian Fisheries. 35(6): 6 1-65. REYE, E. J. (1982) Midges, Man a nd the Marine E nviron men t. Operculum 5(4): 153- 156. SAENGER, P . a nd Mc!VOR, C. C. (1975). Water Quality and Fish P opulatio ns in a Mangrove Estuary Modified by Residentia l Canal Developments. In 'Proc. Internal. Symposium on Biological Management of Mangrove'. Hono lulu, 1974. Vol. II, Uni ve rsity of Florida. ST EER ING COM MITTEE ON CANAL DEVELOPMENTS ( 1984). Recommenda! tions for the develo pment o f canal estates. Conserva tion and Environment , P erth. WESTMAN , W. E. (1975). Ecology of Canal Estates. Search 6( 11 ): 491-497. â&#x20AC;˘

CONCLUSION Proposed canal estate developments in New South Wales come under the general framework of the Environmental Planning and

*

AWWA PAPER INDEX 1966-1987 This issue includes a lift-out with the followin g full title :

*

*

*

Index of Papers Presented to FEDERAL CONVENTIONS 1966-1987 and SUMMER SCHOOLS 1964-1980 and WATER TREATMENT SYMPOSIUM 1965

*

Papers are grouped under 23 subj ect headings arranged alphabetically . Requests for copies of the index should be addressed to the Federal Secretary, A WW A, Box A232, PO Sydney Sth 2000.

WATER December, 1987

17


THE DIRTY DOLLAR AND HOW IT'S LAUNDERED J. G. Parker, B. J. Lyons ABSTRACT The printing of our bank-note currency is a unique industry in this country and produces a range of complex and potentially toxic wastewater streams with high levels of heavy metals, colour, detergents, freon extractable matter as well as high organic and solids concentrations. The 'laundering' or treatment of this unique and complex wastewater stream requires segregated collection and integra. tion of a range of physico-chemical and biological processes to achieve stringent discharge standards. Development , design and operational experience of the Reserve Bank Note Printin g Works wastewater facilities Craigieburn, Victoria is outlined. The Note Printing Works is located 25 kilometres north of Melbourne , covers a site area of approximately 10 ha. and the main building comprises four levels with vario us production processes spread throughout. The wastewater treatment plant is in part located within the basement/ mezzanine floors of the main production building and in part external to the building. Capital cost of the waste treatment facilities was $1.5 m. Monitoring of the facilities since commissioning has demonstrated a consistently high performance, particularly toxicity control for protection of downstream biological processes.

INTRODUCTION The Reserve Bank of Australia is charged with the task of printing the nation' s bank-note currency. Historically this was conducted at the Fitzroy Bank-note Printing Works in Melbourne from which all wastewaters were discharged to the main sewerage system of the Melbourne Metropolitan Board of Works (MMBW). Due to the age of the Fitzroy Facility and its technology, the Reserve Bank through the Department of Housing and Construction embarked on development of a new Bank-note Printing Works at Craigieburn on the northern outskirts of Melbourne, incorporating state of the art bank-note printing technology. As the only options for disposal of wastewater from the Craigieburn facility were to a small regional sewerage system of 1500 EP capacity or a small local stream, stringent effluent requirements were set by the regulatory authorities. Consideration of these requirements and the fact that all other note printing works in the industrialised western world have access to a large metropolitan sewerage system, necessitated development of a wastewater treatment system 18

WATER December, 1987

essentially from 'first principles' achieve the treatment objectives.

to

WASTEWATER CHARACTERISATION AND TREATMENT OBJECTIVES Wastewater Characterisation The principal production processes giving rise to wastewater streams are: • Note printing • Electroplating • Photographic processing • Etching and solvent based processes. Within these four broad categories of waste sources, there are over 75 individual sources spread over four floor levels. The four broad categories of waste sources were defined as shown in Table 1. Characterisation of the four designated waste streams is presented in Table 2. The flow proportions of the four waste streams are: Flow (m'ld) (%)

Waste Stream Alkali (TWB) Acid (TWA) Photographic (P) Concentrated (C)

43 7 10 < l

70 12 17 < l

Total

61

100

Parameter

Source

Designation

Note Printing

Trade Waste Basic stream (TWB) due to the highly alkaline nature of these wastes. Trade Waste Acid stream (TWA) due to the generally acid nature of these wastes. Photographic stream (P) Concentrated waste stream (C)

Photographic Etching and Solvent Processes

B. J. Lyons

John Parker, B.E.(Me lb.)., M .S.(Texas), M.I.E.Aust., M.A.S.C.E. is Managing Director and Director, Engineering Services of WSL Consultants Pty. Ltd. Consulting Scientists and Engineers. Barry Lyons, A.R.M .I. T., A.R.A.C.I., is Director, Scientific Services and Chief Chemist with WSL. Both were involved with the conceptual design, detailed design and operational supervision and monitoring of the Reserve Bank Note Printing Works treatment facilities.

TABLE 3: TREATED EFFLUENT REQUIREMENTS

TABLE 1: WASTE SOURCES AND DESIGNATION

Electroplating

J. G. Parker

Maximum Permissable Limits

pH B.O.D., C.O.D. Sulphate as SO, Sulphite as SO, Silver Cadmium Mercury Iron All other heavy metals

6- 10 300 300 300 15 0.2 0.2 0.005 10 0.5 (each)

All units mg V' except pH in pH units.

TREAT ABILITY

Treatment Objectives An early policy decision was to treat the total wastewater stream and discharge the treated effluent to the small local sewerage system operated by MMBW . The requisite treated effluent requirements set by MMBW are shown in Table 3.

INVESTIGATIONS Overall Process Considerations Due to the numerous, diverse and complex nature of the various waste streams and their wide variation in composition, a systematic laboratory study was under-

TABLE 2: CHARACTERISATION OF WASTE STREAMS PARAMETER

pH B.O.D. , C.O. D. Colour M.B.A.S. Oil and Grease Total Heavy Metals

WASTE STREAM Alkali (TWB)

Acid (TWA)

Photographic (P)

Concentrated (C)

11.5- 12.5 27000-44000 45000-90000 20000-170000 6000-8500 I0000-15000 15-55

2.5-4.0

5- 10 100-500 200-800

150-175

5-50

1-10 > 10000 > 20000 > 20000 > 20000 >20000 > 10000

Note : All units mg L-• except pH in pH uni ts.


taken of the treatability of the four principal waste category streams, both individually and collectively, to determine the most appropriate collection, pretreatment and treatment system. Early results from these laboratory studies indicated that combination of all four principal waste streams and subsequent combined treatment was not feasible due to: • The high oil and grease concentration in the TWB stream from sulphonated castor oil used in the printing process. This formed an emulsion with the other wastes which could not be effectively 'cracked'. • The high alkalinity and surfactant concentration in the TWB stream inhibited the precipitation and removal of heavy metals from the combined waste. • Lack of effective means of reducing colour in the combined total waste stream for all note type combinations. Colour produced from some pigments was particularly · resistant to removal by physicalchemical processes and totally resistant to degradation by biological processes. As a result, further laboratory treatability investigations focussed on the concept of separately collecting the four principal waste streams with provision for appropriate pretreatment prior to combination with the other streams and subsequent further treatment.

TWA Stream The principal pretreatment requirement for this stream, before it could be combined with other waste streams, was to remove hexavalent chromium. Conventional reduction at pH 2 with sodium metabisulphite·was found to be suitable in laboratory investigations . Removal of total heavy metals was required following these steps.

Photographic Stream It can be seen from Table 2 that this stream did not contain constituents requiring special pretreatment measures. The presence of organic concentrations B.O.D. s (100-500 mg L- 1) and heavy metals (5-50 mg L- 1) was entirely compatible with the pretreated TWB and TWA streams .

Concentrated Waste Stream Due to the very high concentrations of toxic components in this stream and the small volume involved, it was determined from laboratory treatability investigations, that pretreatment/ treatment of this stream either individually or in combination with other waste streams was not practical.

Combined Waste Stream TWB Stream The first requirement for effective pretreatment of this stream was to break the emulsion resulting from the presence of sulphonated castor oil. Numerous chemical agents were investigated in the laboratory, from which it was determined calcium chloride was the most effective. The resulting sludge from this treatment exhibited the property of dense packing and difficulty of handling upon any mechanical working. The effluent from this initial emulsion split still contained very high residual colour values (10 000-100 000 Pt-Co units) which was extremely variable. In order to reduce the colour concentrations to acceptable levels, it was found necessary to dose the effluent from the emulsion splitting stage with a chemical flocculant and polymer. Numerous combinations were investigated in the laboratory including the following chemical flocculants : • Alum • Poly Aluminium Chloride (PAC) • Lime • Ferric Chloride Ferric chloride provided the most effective removal of colour consistent with minimum production of sludge at the least chemical usage cost. The polyelectrolyte found to be most effective as a flocculant was the polymer , 'Magnafloc' 156. Following this further chemical pretreatment with ferric chloride, the resulting effluent was acceptable with respect to all parameters except organic concentration (BOD /COD) and heavy metal toxicity.

Combination of the pretreated TWB and TWA streams with the photographic stream resulted in a total waste stream still requiring removal of heavy metals and organic matter . By combining these streams at this stage the excess alkalinity in the TWB stream could be utilized to precipitate the heavy metals in the total combined waste stream. As the residual organic matter following this heavy metal precipitation stage was still excessive, further treatment by biological processes was required in order to achieve effluent quality objectives .

Due to the high COD/ BOD, ratio in the effluent at this stage t f treatment, the extended aeration mode of the activated sludge process was chosen for laboratory investigation to determine full scale design parameters. These inve st iga tions indicated a nutrient deficiency in the waste, but once this was corrected, sa ti sfac tor y BOD/ COD reduction was achieved. These comprehensive treatability investigations conclusively demonstrated the total waste stream could be satisfactorily treated to achieve the effluent quality objectives. -w.

FULL SCALE PROCESS OUTLINE From the results of the laboratory treatability investigations, the full scale plant was designed. It was based on separate collection of the four principal waste streams and the integration of the physico-chemical and biological processes outlined in order to achieve the treated effluent quality objectives. A simplified .schematic process flow diagram of the full scale plant is shown in Figure 1. It will be seen a pressure filtration step was included in the flowsheet to protect the biological process from heavy metal hydroxide carryover and thus protect it from toxic inhibition.

DESCRIPTION OF FACILITIES The Note Printing Works is located on the Hume Highway at Craigieburn, approximately 25 kilometres north of Melbourne. The main ).fate Printing Works site covers an area of approximately 10 ha . and the main building comprises four levels with the various production processes spread throughout. The wastewater treatment plant with all the TWB and TWA pretreatment facilities

Figure 1. Simplified schematic process flow diagram. WATER December, 1987

19


and plant mo tor control centre are located within the building in the basement/ mezzanine floor areas. The heavy metal removal and biological treatment facilities are located external to the building and below gro und for security reasons .

PERFORMANCE AND COSTS Performance Since the plant was commissioned, performance has consistently met the design objectives with the exception of a short period when the total cyanide concentration in the discharge marginally exceeded the final effluent requirement. After exhaustive analytical investigation, this occurrence was traced to the fact that one of the pigments used in this printing in k decomposed in alka line waste condi tions to produce a cyanide com. pound . Once the source of the cyanide had been successfully identified, the problem was readily eliminated. Performance through the vario us stages of the treatment plant is shown in Table 4.

Costs Total capital construction cost of the

SOUTH AUSTRALIAN BRANCH NEWS Continued from page 11 Tentative meeting dates are: • Friday 26th February: Don Bursill, Chief Chemist, State Water Laboratory, speaking on his recent world trip. • Wednesday 6th April : Discussion of the Mt Lofty Ranges Review • Friday 6th May: A seminar on the subject 'On-site Wastewater Treatment'.

People Federal President Mike Dureau attended the August AGM and presented an A WW A Service Plaque to Keith Lewis for outstanding service to the water industry of Australia. Keith was Director General Cif the EWS Department in SA from 1974 until his retirement in 1987. SA Branch members congratulate Keith on being

Keith Lewis receiving the Service Plaque from Federal President Mike Dureau at the August AGM. 20

WATER December, 1987

TABLE 4: TREATMENT PLANT PERFORMANCE PARAMETER

pH B.O.D. , C.O.D. M.B.A.S. Oil and Grease Total Heavy Meta ls Colour

TREATMENT STAGE Post TWB Pretreatment

Post Heavy Metal Removal

Post Biological Treatment

8-1 1 2000-5000 4000-8000 10- 100 20-50 10-25 500- 1000

9-9.5 1500-3000 3000-4000 1-5 10-20

7-8.5 <300 <300 0.5-1.0 5- 15 1-5 < 300

5 300-400

Note: All units mg L-' except pH in pH units .

entire wastewater treatment faci lities was $A l. 5 m. Considerable costs were incurred purely due to security considerations including: • Location of a major part of the treatment system within the main building. • All external treatment facilities were located below gro und , including pressure filtration facilities. • Sizing of all external area stormwater pipework to prevent entry to the site by humans.

CONCLUSIONS Systematic laboratory treatability investigations of complex and potentially toxic wastewater streams from bank-note printing, indicated the efficacy of

selected to receive this distinguished award. Peter Hoey, Principal Engineer, Planning with EWS Water Resources Branch has recently been overseas in Thailand. He was involved with Kinhill E ngineers for the Royal Thai Irrigation Department in the Chi River Barrage Stud y in North East Thailand .

segregated collection and integration of physico-chemical and biological processes for successful treatment of such complex effluent. Monitoring of faci lities since commissioning has demonstrated a consistently high performance, particularly of toxicity control , for protection of downstream biological processes .

ACKNOWLEDGEMENTS The authors gratefully acknowledge the assistance and cooperation of the Reserve Bank of Australia Note Printing Works Branch and the Department of Administrative Services, Victoria-Tasmania • Region.

for teflon tube ultraviolet disinfection units, now assemb led from mostly Australian made components. UVTA is the sole manufacturer. Ultraviolet disinfection can be used for drinking waler, treated wastewater, cooling towers and pool and spa water and demand is expanding locally and overseas.

Of Interest New guidelines are being prepared in South Australia for septic tank installations by a Working Party comprising officers from the SAHC, Environment and Planning and EWS. Apart from increases to tank volumes, major changes are proposed to effluent disposal requirements. In future, a land capability approac h will possibly be used to assess the suitability of a conventional septic tank/soil absorption system for onsite disposal. If such a system is unsuitable, a more sophisticated form of onsite treatment may be required. As these changes are likely to generate considerable interest, the Association is planning a seminar in May 1988 to cover all aspects of alternative onsite treatment and disposal methods (see Programme) . The SA Government has recently set up the Mount Lofty Ranges Review, an interdepartmental study to examine all types of land use in the Mount Lofty Ranges, including water catchment areas. Submissions fro'm interested people are invited, and queries should be directed to the Review Office, telephone 216 7777 . A new factory and office building has been opened by Ultra Violet Technology of Australia to meet the increasing demand

(Left to right) Tony Gardner, UVTA Managing Director; Scott Cameron, Senior Specialist, SA Health Commission and Makham Jawar, President, Industrial Water Technology, California at the official opening on August 7th .

New Members The following were acce pted as members at the last committee meeting: Paul MacDonald (EWS), Ian Baldwin (SAHC), Peter Swanson (Kent Instruments). The Committee welcomes the new members and warmly invites them to par• ticipate in Branch activities.


SETTING PRIORITIES for

R&D IN THE- WATER SECTOR Dr. Peter Nadebaum for the Australian Water & Wastewater Association ABSTRACT As part of the national debate on the setting of priorities for funding R&D in the water sector, the Australian Water and Wastewater Association (A WWA) reviewed current levels of expenditure on R&D and circulated a questionnaire to a crosssection of the Water Industry to determine the priorities for R&D . Analysis of the results indicates that the current level of technological research in areas such as water and wastewater systems is very low as a percentage of current capital expenditure, a11d is less than the perceived need of the Water Industry. It is concluded that R&D funds should be directed towards areas which offer the greatest economic benefit to Australia, and not to 'needs' identified by eminent individuals in the Water Industry .

COMPARISON OF CURRENT R&D EXPENDITURE AND WATER INDUSTRY R&D PRIORITIES _ The current distribution of R&D expendit re in the water sector determined by an analysis of Streamline 1986 data is compared in Figure I with A WRAC funding patterns and the R&D priorities perceived by the Water Industry. The figure shows the percentage allocation of total R&D funds to specific areas that occurred in 1986, the percentage allocation of A WRAC funds that appears likely to occur in 1987/ 88 (Ref. I), and the percentage allocation of total funds suggested by questionnaire respondents as desirable. ,o~ - - - - - -- - - - -- - - -- - - - - -- - --, 35

INTRODUCTION

30

The Australian Water and Wastewater Association (AWWA) has _reviewed the current R&D funding of the water sector, and has circulated a questionnaire to a cross-section of the Water Industry. Two papers (Ref. 1) detail the results of this analysis. This paper summarises the major findings. · The infrastructure in Australia for water supply, sewerage systems and stormwater involves very large investment (Ref. 2) including: • $2000 million present capital expenditure per annum • $1400 million backlog of justified capital works • $400 million per annum average cost of decay of existing assets. With investment of this order, it is clear that significant R&D expenditure is warranted, and that the expenditure should be directed to achieve maximum return, for example, in optimising the use of existing assets, in developing improved maintenance methods, and in developing new and improved systems and approaches which will enable the desired services to be provided with minimum overall capital expenditure.

SOURCES OF R&D FUNDING An analysis of the 'Streamline 1986' compendium of R&D projects to determine the source of R&D funds is shown in Table I. The analysis indicates: • Public funds, particularly through Government Authorities and research organisations such as the academic institutions and CSIRO, account for 90% of the water sector funding. •Private industry accounts for only a very small portion of R&D activity.

TABLE 1. SOURCE OF AUSTRALIAN R&D FUNDS % of Total

Amount Funded

No . of Projects

( X $M)

Government Authorities (including EPA, SPCC, PWD, DWR) Academic Institutions CSIRO Industry and Consulta nts Wa ter Boards Other (including A WRC , A WRAC)

37 30 14 IO 4 6

15, 10 12.24 5.83 4.05 1.50 2.43

365 296 141 98 36 59

100

41.5

995

Dr Nadebaum is a member of the Victorian Branch Committee and is with Consulting Engineers Camp, Scott & Furphy.

"

~

WATER INOJSTRY QUESTION NA IRE RESPONS(

0

OV ERALL CURRE NT FUNDING

~

AWRAC FUNDING

25

~

I

20

10

o Ld=>,J_...L.<:L::1:::,J..__.J:::..1;,..C:,J._L&.:.:;J___t~µ=,,L.t:..t'.c.D.J_.t:...1=:.J_.L..<:Lc.L:::..

,---,-..._

WATER

WATER

INDUSTRY

WATER

C(ll£CT

TR EATMENT

OIJALITY

ANO TREATMEN T

ANO RE TICUL ATION

AN D IMJUSTRIAl WA STES

SUPPLY MA NAGEMENT SUPPLY

WASTE WATER

GROUNDWAJER AGA(ULT\JRAL AQUATIC USES

ECOSYST EM S

ALLOC ATION ANO DEMAND

Figure 1. Current distribution of R&D Funding compared with perceived priorities.

Figure 1 shows that the current overall R&D expenditure emphasises aquatic ecosystems, with significant expenditure also being directed towards agricultural uses, groundwater, water quality, and water management, supply allocation and demand. It can be seen from Figure I that R&D funding directed towards wastewater collection and treatment and water treatment and reticulation, accounts for only 11 OJo of overall current funding. This corresponds to some $4.5 M, and when compared with the annual expenditure of $2000 M on raw water supply, sewerage systems and stormwater infrastructure, the $1400 M backlog of justified capital works, and $400 m on decay of existing assets, it can be seen that the R&D is in the order of 0.1-0.207o of the required total annual capital expenditure. This is inadequate, and a higher level of effectively directed R&D could yield very significant returns to Australia through savings in capital expenditure.

A WRAC Funding A broad picture of the current emphasis in R&D funding was obtained by assessing the likely expenditure under each of the major A WRAC programmes. While necessarily very approximate because details of expenditure under some of the programmes have not yet been defined, the broad conclusions are: • The pattern of distribution of R&D funds by A WRAC tends to follow the current overall R&D funding pattern • Water, wastewater and industrial waste R&D receives only minor A WRAC support WATER December, /987

23


• There is a strong A WRAC emphasis on R&D related to aquatic ecosystems.

Water Industry R&D Priorities A questionnaire seeking information on R&D priorities was circulated to A WW A members in NSW , Victoria, South Australia and Western Australia. One hundred and nine completed questionnaires were returned, representing a good cross-section of the Water Industry . Responses were obtained formally representing the views of major and smaller water boards , various government authorities, consulting organisations, research organisations, contracting firms, equipment supply firms , and industrial companies. In addition , there ·were a number of responses from individuals in the Water Industry. A detailed breakdown of respondents is given in Reference 1. The respondents indicated that : • A major portion (740Jo) of R&D funding should be directed towards applied R&D, with 470Jo being of direct benefit to the Australian Water Industry, and 270Jo of benefit to Australia through export of income earning goods or services. • The on-going role of pure research was recognised, and it was · indicated that 22 OJo of R&D funds should be allocated towards this area. The priorities for specific areas of R&D compared with current expenditure are shown in Figure 1. The Water Industry respondents indicated: • The major portion (54%) of R&D funds should be directed towards technological areas involving water, wastewater and industrial waste collection and treatment. • R&D areas with intermediate priority are water supply management , supply allocation and demand; and groundwater. • Areas which should receive a low proportion of the total water sector R&D funds are aquatic ecosystems, and agricultural uses. • The four R&D themes identified by A WRAC to require a priority in funding under the National Priorities Programme were included in the questionnaire. These themes centre on topics within the aquatic ecosystems, and water management, supply allocation and demand areas . These themes were not considered significant from the point of view of the respondents , and it was indicated that they should receive only 1OJo of the total fund s (Ref. 1). A breakdown of the response with various respondent groups, such as water boards, government authorities, research organisations, industry and consulting organisations indicated that there was general agreement in R&D funding priorities, and the priorities of each group were similar to the priorities of the respondents overall shown in Figure 1. The questionnaire also sought information on the priorities for a large number of specific research themes, and a detailed analysis of these priorities is given in Reference 1.

HOW SHOULD R&D FUNDING PRIORITIES BE SET? The setting of R&D funding priorities is a difficult task, and has been the subject of considerable.national debate . The recurring themes in this debate with regard to Australian industry as a whole are: • the low overall level of R&D expenditure compared with other countries • the low level of applied R&D compared with basic research • the low ratio of private sector to public sector R&D . The analysis of current funding patterns and the Water Industry priorities shows that these broad conclusions also clearly apply in the Water Industry. A review by the National Science and Technology Analysis Group (Ref. 3) has considered the problem in detail, and has formulated a series of recommendations for the funding of R&D based on the fundamental philosophical assumption: • An important objective of R&D is that it should generate wealth and benefits for Australia . This basic assumption also underlies the debate by the Federal Government Department of Industry, Technology and Commerce, on how to best direct R&D funding (Ref. 4). The approach taken by A WRAC to date appears to have been to direct funding towards areas of 'need' identified by eminent individuals in the various water s·e ctor fields of endeavour, rather than with the objective of maximising returns. 24

WATER December, 1987

Instead of this approach, the A WWA ~uggests that: • Funding of water sector R&D should be based on priont1es which offer the greatest economic benefit to Australia. • Key areas for R&D funding should be identified which have the potential to provide the greatest economic return to Australia, recognising the skills and resources available in Australia and the potential application areas in Australia and overseas. Industry associations, such as the A WWA , can play a significant and potentially a leading role in such an analysis. The A WWA in particular has a broad base of membership from the Water Industry and members with the detailed knowledge required to prepare an estimate of the potential economic benefits that can flow from R&D . it is suggested that: • A WRAC consider involving the A WW A as an active and perhaps leading participant in identifying areas of R&D which might yield the maximum economic return to Australia.

...

ACKNOWLEDGEMENTS The members of the A WW A R&D Committee have provided a significant time input to the consideration and analysis of R&D priorities in the Water Industry. The Committee Members include: E . A. Swinton (Chairman), Dr. W . Drew, T. Fricke, N. Howard, Dr. P. Nadebaum, Dr. N. Norman, J. Parker, Dr. A. J. Priestley, R. J. Turney. In addition , particular acknowledgement is made of the support given by Camp Scott Furphy and WSL Consultants.

REFERENCES 1.

NADEBAUM, P . R. , "Achieving a Balance in R&D in the Wa ter Secto r", a nd " Austra lian Water Industry R&D Need s - An Ana lys is of a Questionna ire C irculated to the W ater Industr y" , Papers submitt ed by the A WW A to th e AWRAC National Wa ter Research Seminar , Canberra , September, 1987 . 2. LONGSTAFF , A. G. and BARNES, F. B. , " Au stralia's H ydraulic Infrastructure - Planning for Renewal " , Water p.20 June I 986 . 3. Na tional Science a nd Technology Ana lys is Group , " Science a nd Technology in Au stralia - A Review of Go ve rnm ent Support ", AGPS, 1986. 4. Depa rtment o f Indu str y, T echn ology and Comme,ce , "Selectin g T echnologies for the Future : A Discussion Paper ", AGPS, December I 986. •

"

AUSTRALIAN WATER & WASTEWATER ASSOCIATION

MEMBERSHIP Four Membership categories ava ilable: • Member - qualifications su itab le for membership in the Inst. of Engineers (Aust.) or other re levant professional bodies ($32 p.a.). • Associates experience in the water and/or wastewater industry ($32 p.a.). • Student ($6.60 p.a.). • Sustaining Member - an organisation invo lved in the Industry wishing to sustain activities of the Associat ion ($150 p.a. plus State lev ies where applicable). Application forms and further information are available from Branch Secretaries, see page 1.


NATIONAL WATER RESEARCH SEMINAR CANBERRA - 'SEPTEMBER, 1987 P. R. Nadebaum INTRODUCTION The Seminar, organised by Australian Water Research Adivsory Council (AWRAC), was held in Canberra on 17th and 18th September, 1987. The seminar was atte nded by the leaders of the water indu stry, and representatives of the many di verse gro ups within the industry, including academic institutions, research organisations, various divisions of CS IRO , the urban authorities, govern ment authorities, consultants, the irrigation industry and the Australian Water a nd Wastewater Association . The objective of the seminar was to develop a statement on national water research priorities, priorities which wo uld: â&#x20AC;˘ direct available water research dollars into investme nts likely to give the best returns from a national viewpoint ; and â&#x20AC;˘ span across disciplines to help water research break out of its traditional discipline-oriented framework. As a preliminary of the Seminar, A WRAC commissioned a research review paper to provide statements of research priorities from the 'researcher' viewpoint. Also, five 'thematic' or industry section oriented papers were prepared which drew on the research review papers. These, with other papers, including the A WWA submission, were distributed prior to or during the meeting. The seminar was stru ctured aro und the five thematic papers, with a short presentation by the author of each paper, followed by six or seven "comment " papers. Following the latter papers, other comment was sought from the floor.

THEMES The detailed analysis presented in the thematic papers and the accompanying research review papers have been published by A WRAC and will not be discussed here. This report is directed primarily to the comments of the rapporteurs of each session and the concluding phase of the Seminar.

WATER RESOURCE MANAGEMENT RESEARCH A need was seen to bring the industry and researchers together and to ensure that research should be responsive to the influences of society. There is also a need for a synoptic description of the problems involved in water resource management and research into the institutional , legal, and economic aspects of water resource manage ment. Other important research areas are charging policies and allocation techniques, factors which facilitate control of water demand , climatic change and the distinction between protection and the natural environment and meeting the demands for water and the utilisation of the resource .

CATCHMENT AND IN-STREAM MANAGEMENT RESEARCH The discussions on Catchment and In-Stream Management centred on the important researc h needs of aquatic ecosystems, particularly relati ng to rivers and related wetlands. Taxonomy was seen as an important item and a recurring theme in variou s sessions was the problem of pesticides in the environment. Research should also be directed towards the stud y of river catchments and the strategies for the management of catchments, and there is a need for policies and strategies relating to water allocations.

MAJOR URBAN WATER AND SEWERAGE SYSTEMS RESEARCH Important research priorities include: review of the overall management structure of the major urban a uthorities and alternative management structures, ac hievement of more cost effective

operation of water and sewerage systems, and the development of better methods of asset management, including the determination of asset li fe, and better and more efficient automation of operating systems. There is also a need for further work di rected to the maintenance of health and protection of the environment with specific reference to the effect of chemicals, and the management of water resources.

MINOR URBAN SECTOR RESEARCH T he Minor Urban Sector of the Water Industry has been neglected in the past and has experienced serious problems, having neither the financial or management resources to provide services for its consumers comparable wit h the major urba n authorities . A particular difficulty arises from the varying institutional arrangements of the minor urban authorities and the problem, in some cases, of persuading their consumers to accept the res ul ts of research. A need is seen for demonstration projects and for the developments to be 'appropriate', wit hout necessarily involving high technology. It is fe lt that demonstration projects wo uld be valuab le which emphasise improved management, financial and administrative techniques, and appropriate technology, particularly in regard to low cost treatment a nd distribution systems. Finally, because of t he low profile of the minor urban sector, there is a need for an appropriate mechanism to increase industry aware ness of this sector and to help direct useful research towards it.

IRRIGATION RESEARCH The greater competition for the -evailable water resource and the need to maximise the efficiency of water use are identified as important issues. A need is seen for research into both institutional change and institutional factors and also the development of better know ledge of water usage and water saving techn ologies. Pricing and resource management are important issues; the problems are complex and base data as to who does what, who wins a nd loses, and just what volumes of water are used, are lacking and need to be identified. There was a call for furt her research into the use of agricultural chemicals and pollution , and research into gro und water.

DISSENTERS CORNER A session was provided to enable those who had not been included in the main sessions to have their say. The A WW A presented the results of its survey of the Water Industry R&D priorities and compared these results with present fundin g priorities. In addition , detailed papers were circulated by the A WW A to the A WRAC seminar delegates and o rganisers for their reference. Others raised specific areas for research , including: atmospheric studies such as cloud seeding; gro und water , especially in support of the export industries such as mining; studies into rainfall and climatic trends; palaenhydrology; research into estuarine environ ments, and the importance of artificial recharge . T here was some debate as to whether Australia is in fact unique with regard to its environmental systems and water problems . There were two schools of thought, one claiming uniqueness, the other suggesting that in fact the Australian environment is very similar to much of the world and we should take adva ntage of the similarity to export our knowledge to the rest of the world . Questions were raised by some respondents regarding the cross sector priorities, including: the issues of whether researc h should be commonwealth or industry fund ed; which research would really be to the overall community benefit and have relevance on the WATER D ecember, 1987

25


national scale; whether specific areas would offer potential for export reven ue; and to what extent specific R&D will have application, and thus yield a benefit. A question was raised regarding the validity of the Seminar conclusions because the participants generally reflected the status quo of R&D funding and not necessarily the overall makeup of the water industry. Would the seminar not simply endorse the status quo and not be able to take an independent stance and select balanced priorities for the overall benefit of the industry and of Australia?

These comments bring into focu s the p~arisation that existed at the Seminar between those interested in the natural sciences, and those in technology . The A WWA submission was questioned vigorously by those researchers interested in the natural sciences and they doubted that the priorities identified by the A WWA questionnaire were representative of the water industry. T here seemed to be strong support by AW ARC committee members for the natural sciences, and as a second priority , for the administrative, legal and fin a ncial aspects of the water industry . It will be interesting to see just what water sector R&D priorities A WRAC formul ate as a result of the Seminar . Notwithstanding the personal views of A WRAC members, there would seem to be strong argument for A WRAC not to walk away from the technological sector of the industry, but to take an active and persuasive role in providing the catalyst for a significantly improved and effective R&D effort by the water industry. Keith Lewis, the Chairman of A WRAC, reviewed the overall proceedings and commented that the research priorities identified as a result of the Seminar wo uld not be fixed but would be upgraded regularly, with a national biennia l research conference providing the fo cus for this. •

CONCLUDING REMARKS Dr. John Paterson provided some interesting concluding remarks. As Chairman of the committee which organised the seminar he regretted that the structure of the seminar did not rea lly permit the ro les issue to be dealt with adequately and stressed that it was difficult to determine the relative priorities between various broad programme and theme areas . Dr . Paterson suggested that technological research should be fund ed by the Water Boards themselves, rather tran by A WRAC. He felt that technological research had been limited in its success and that it was inappropriate to direct furth er fund s towards this area. *

*

*

*

*

RESEARCH PROJECT

• • • . • . G-Qiiaiiii~ii•• i • · ~iliiiiii CONFERENCE

The British Council

SCIENCE & TECHNOLOGY for REMOTE COMMUNITIES Murdoch University July 18-19, 1988

APPLICATIONS OF REMOTE SENSING FOR NATURAL RESOURCE SURVEYING

PAPERS CALL PRELIMINARY NOTICE Key Speaker will be Dr Bruce Walker, Centre for Appropriate Technology, Alice Springs. Topics will include: water supply, waste disposal, energy, shelter, communications, health and nutrition, employment and training , forestry, agriculture, land use and management, development strategies. 200 word abstracts due January 31. Papers due May 1st. Information: Dr K. Mathew, Environmental Science, Murdoch University, South St, Murdoch, W. Australia 6150. Tel. (09) 332 2501. *

* AWWA

SUMMER SCHOOL '88 Hobart -

Feb.2~26

With the theme 'Optimizing the Use of Water Industry Assets', this school is a response to continuing demand for post-graduate instruction in the industry.

Keynote speaker is Jack Jeffry, Director and General Manager, Nth. Surrey Water Company, Director Sutton Water Company, Dep . Director Water Research Council. Enquiries: Secretary AWWA, PO Box 78A, Hobart, Tasmania 7001. 26

·································•: u

WATER December, 1987

Silsoe, Bedford, 10-22 April '88

The main aim of this course is to give senior decision makers the necessary information to enable iden tification of appropriate remote sensing for projects and evaluation of proposals . The course will be directed by Dr John C. Taylor and will provide participants with an up-to-date overview of principles and methods. Visits will be made to centres of information and UK manufacturers of image processing equipment. Fees: Residential 1125 pounds, nonresidential 735 pounds. Applications should be made immediately to the British Council, PO Box 88, Edgecliff, NSW 2027.

*

*

*

PROJECT MANAGEMENT SYMPOSIUM Brisbane, June 18-23 '88 A Joint Venture by the Project Managers Forum and QIT will present 35-40 papers directed to the central theme 'Building Effective Project Teams' and cutting across all professional and industrial barriers. The event will include week-end workshops, two days paper presentation, one day summary and site visits. Inquiries: Q Search/Queensland Inst. of Technology, GPO Box 2434, Brisbane 4001.

REED BED TREATMENT OF WASTEWATER A joint research project is to be established between the Mornington Peninsula and District Water Board and Chisholm Institute of Technology, Water Studies Centre, to investigate the Reed Bed Method (RSM) of treating "'{astewater. The three year project involves establishment at the Board's Frankston Wastewater Purification Plant, of 6 pilot scale reed beds , in October, having a total area of 900 square metres. Gravel and modified soils will be planted with Phragmites australis with the wastewaters passing through the beds. The processes involved in Biochemical Oxygen Demand (BOD) and nutrients (nitrogen and phosphorus) removal, particularly in the regimes around the root zones of the plants , will be studied in some detail. The research team includes Mr Rex Brown, Engineer, Programmes & Research , Mornington Peninsula & District Water Board, Mr Tom Davi es and Dr Barry Hart of the Water Studies Centre, Chisholm Institu te of Technology. A Steering Committee of exper;s in the field has been established to guide the research. At its first meeting on September 1, 1987, the Committee reviewed the latest overseas information , together with developments in NSW which are yi elding promising results from wastewater treatment in gravel beds using biological methods. The project is expected to complement the work being done in NSW. Mr Davies has recently toured European reed bed plants and a 'perspec tive ' paper will be published in a forthcoming issue of Water.


Polyelectrolyte in Sludge Conditioning Use of Rheol¡ogy for Control T. R. Bridle and C. K. Hertle INTRODUCTION The use of on-line measurement of conditioned sludge rheology has made it possible to control polyelectrolyte dosage rate in sludge dewatering processes. The sensitivity of rheological properties to changes in solids concentration and sludge dewaterabi lity is extremely good. lntrodui::tion of the Sludge Conditioning Controller (SCC) system to the Australasian wastewater treatment industry prov1d~s plant operators with the opportunity to better control their sludge dewatering operations while reducing operating costs associated with sludge dewatering. Fu ll scale operations in Canada have consistently shown a 25 % reduction in polyelectrolyte usage. . Sewage treatment costs comprise a significant portion of our total u~ban infrastructure expenditures and unfortunately are escalat ing at a rate greater than the national consumer price index. Since sewage sludge management costs exceed 50 % of total sewage treatment costs (Proctor and Redfern), authorities are continually examining their slud ge management schemes with the objective of minimising these costs . Most sludge management system costs are very dependent on volume treated and thus sludge volume reduction is often the first , and most important unit operation in a treatment scheme.

SLUDGE DEWATERING Historically, sludge drying beds, settling basins or holding ponds are the most common 'volume reduction' operations in Australia. With the increased pressure on land use, potential odour problems and inclemental weather implications, there is a trend towards mechanical dewatering of sewage sludge at medium to large treatment plants ( > 10 mUday). Mechanical dewatering is not land or labour intensive, can control odour and operates effectively regardless of climatic c~nditions, it d?es however require chemical conditioning . With few except ion s mechanical dewatering systems must be preceded by some form of conditioning in order to flocculate the sludge and increase the ease of water removal. The most common mechanical sludge dewatering devices in Australia are centrifuges and belt filter presses. To function efficiently these devices require the feed sludge be superflocculated . In the past inorganic flocculants such as lime ferric chloride and alum were used; their use has however ~II but been eliminated by introduction of high molecular weight cationic polyelectrolytes. These polymers are more attractive to use sinc_e dosing rates of on ly 0.5 to 1% of sludge by weight are required, compared to up to 30 % for inorganic floccu lants. They are also eas ier to handle than their inorganic counterparts. Pol_ymers are . however expensive and can cost up to $10lkg: It Is no surprise then that chemical conditioning costs comprise up to 50% of sludge dewatering operating costs (Proctor and Redfern). Until recently the only attempt at controlling polymer dosage to dewatering processes has been through measurement of sludge density. There is however great difficulty in relating this to total sol ids as density variations in the range of interest \2¡7:o T.S.) are very small. Also no indication of dewaterability Is given by these methods. The classical methods of measuring _dewaterability (capillary suction time and spec ific cake resistance) are however not feasible for cont inuou s contro l. With the recent introduction of the Sludge Conditioning Controller (S.C.C.) to the Australasian market dewatering can Trevor Bri~le is the Managing Director of Campbell Environ mental Ltd. in Perth, Western Australia. Chris Hertle is an Environmental Control Engineer with Campbell Environmental in Perth, Western Australia.

Central Contro l Panel

c::::J CJCJCJ CJ CJ CJ CJ CJ CJ

OD

To Polymer Pump Controllers

0 To other ' - - -- Sample Vesse ls

One central control panel supports up to four sample vesse l assemblies Sample Vessel Assembl y

Fig. 1. Sludge conditioning controller. now be monitored on-line and hence control of chemical condi tioning is poss ible in a reliable manner.

.

THE SLUDGE CONDITIONING CONTROLLER (S.C.C.) The Sludge Conditioning Controller (S.C.C.) is a patented technology marketed in Australia, New Zealand and S.E. Asia by Campbell Environmental Ltd. It relies on the measurement of rheological properties for sludge characterization. The system consists of two major sub-assemblies, the sampling system_ and a _central control panel (Figure 1). One sampling vessel Is required for each dewatering unit, while the central control panel can configure up to four inputs. In aut<;>i:iiatic mode the S.C.C. tracks changes in ~ewaterab,_llty of the sludge to keep the press operating at optimal cond 1t1ons . A samp le of flocculated sludge is all owed to flow under gravity into the bottom of the samp le vessel. Once the vessel fills, the rheological sensor is rotated at a set acceleration to a certain speed and its output is transmitted to a central control box for analysis and control action on chemical conditioning rate. After the measurement cycle is completed , the sample is drained and the vessel and measuring head are thoroughly rinsed for 30 seconds. A comp lete samp le cycle can be comp leted every 9~ seconds; however a typical interval is 5 minutes. The system_ Is_ rugged , ha~ only three moving parts, is self cleaning , has bu1lt-1n d1agnost1cs and is easily installed in new or existing installat ion s. Be_c_ ause characteristics that affect dewatering are sludge spec1f1c, the S.C.C. is 'tuned' for each installation. The dewatering operations are manually brought to optimal conditions and the resulting rheograms are used as the reference or set-point criteria. The contro l programme also incorporates a 'minimum seeking ' algorith~ which decreases the po lymer dose by small preselected increments even when al l cond itions are met. This tend~ to cyc le around a minimum value which meets set point requirements . Not only does the computer examine measured data for control action but it also analyses the operation of the measuring system and annunciates any mechanical faults or possible system bloc kages . WATE R December, 1987

27


-...' c,)

~

.....

w C,

<C

"'0

There are at present two S.C.C's bein,,9 used on full scale plants in Canada with a third unit currer\11y being installed in the U.K. Figure 2 shows S.C.C. performance data from the Guelph, Ontario sewage treatment plant. Digested sludge at th is fac ility is dewatered on two 2 m Komline-Sanderson belt fi lter presses. One press was outfitted with the S.C.C. in November, 1986 and an extensive field validation programme was carried out in conjunction with Environment Canada's Wastewater Tec hnology Centre. Duri ng manual contro l po lymer dosage vari ed from ap proximately 4 to 8 kg/tonne with an average of 5.7 kg/ton ne. The S.C.C. however controll ed po lymer dosage from about 3 to 5 kg/tonne with an average of 4.3 kg/tonne, demonstrating a saving of 25% (Bridle). The controller also produces more consistent cake solids, reduced bl inding of belts (due to excess polymer dose) and generally provides fo better press operation.

12 MANU .AL CONTROL

10

8 6 4

C

cc: 12 w

AUTOMATIC

CONTROL

:::E

> 10

...J

0

8

ll.

6 4

REFERENCES

1

2

3

4

5

7

6

8

BR IDLE, T. R. et. al. ' Energy Efficient Management of Munic ipal Sewage and Sludge ', presented at the Int. Symposium on River Pollution and Management , Shanghai, PRC , Oct. (1987) . CAMPBELL, H. W. et. al. 'An In st rum ent for Automated Control of Sludge Conditioning '. Proceedings 9th Annual Symposium on Wastewater Treatment , Montreal (1986). PROCTOR AND REDFERN , 'Development of a Methodolog y to Investigate the Cost Effectiveness of Various Sludge Management Systems', â&#x20AC;˘ prepared for Environment Canada, (1987).

9

TIME (hours) Fig. 2.

sec

performance data.

*

ANC MEETING The Aust. National Committee met in â&#x20AC;˘ Sydney on 29th September, and was preceded by a meeting of the Executive Committee. The President of A WWA attended . The meeting adopted a budget for 1988 which took into account falling interest rates on the ANC's investments, the probability of changes in the exchange rate, the fees fixed by the International body and local commitments of ANC. The combined fees for IA WPRC and ANC membership were fixed as: Corporate I - $800 Corporate 2 - $500 Individual - $80 The Constitution was updated to incorporate changes in the IA WPRC Constitution and some local variations. Copies will be mailed to members in the near future. A draft corporate plan prepared by Mr. Henry was received and discussed briefly fo llowing comments by the members of the Executive - a copy amended as decid28

WATER December, 1987

*

*

*

ed by the Chairman will be forwarded to all members for comment. A meeting of ANC will be held during the 1988 Brisbane Conference. This meeting will discuss the Corporate Plan and other initiatives and consider any matters which members care to raise. Lance Bowen was nominated to assist Mr. Henry in obtaining Australian contributions to the Journal 'Water Quality International'. News items may be submitted to 'Water' or the Secretariat. Because Mr. Henry's commitments with the Brisbane Conference will clash with the Governing Board Meeting, he suggested that the Chairman replace him on the Governing Board. This was adopted, to date from 1st April 1988 . Mr. Dooley resigned as Secretary, as he is leaving the Sydney Water Board and Mr. Greg Cawston was appointed in lieu. Mr. Smyth resigned as the Vice Chairman and Dr. Garman accepted nomination to the position. Mr. Smyth will continue as a Director . Arrangements for the Brisbane Conference were outlined by Mr. Henry and the meeting offered several suggestions for consideration by the Conference Committee. The report of the Chairman, Mr. P. Michael: 'Over the past few years considerable emphasis has been placed on identifying the ro le of the ANC in this area of increasing awareness of water pollution issues and the emergence of highly active national bodies with interests and objectives similar to those of IA WPRC. Particular attention has been given to confirming the appropriate relationship with A WW A.

*

We have discussed at length the benefits of retaining the ANC and agreed it has a definable role commensurate with the needs of the industry in Australia and with the added advantage of a well structured and efftctive international support network. The interest shown by ANC executive members in setting the scene for IA WPRC in this changing environment has been most encouraging'. Having accepted the challenge to continue the ANC as a valuable component of the Water Industry it was also considered necessary to put our own house in order for the current environment. Items such as the revised constitution, a draft corporate plan and a review of our involvement in Technical Specialist Groups are now part of the agenda for the Executive's consideration. Last year's decision to process some of these outstanding matters through a working party has proved successful. The inclusion of Peter H ughes (Executive Director, A WW A) has been particularly beneficial in providing an avenue for communication and clarification of roles and activities. Looking forward to 1988, there is a need to reinforce the presence of ANC in areas such as the Technical Specialist Groups, to encourage the use of IA WPRC in the resurgence of activity in water and wastewater research, and to advertise the advantages that IA WPRC can offer across the many facets of the industry. To this end we should recognise the opportunity offered by the joint conference planned for Brisbane next July. LEON HENRY


TOWARDS AFFORDABLE AND EFFECTIVE WATER TREATMENT A. G. Strom and J. A. Crockett ABSTRACT While Australia does not experience the intensity of waterborne disease met in other countries it is still essential that our water supplies, with their complete public acceptance, are safe and properly disinfected . Chlorination only of raw water, can often be inadequate, as the water may not be clear, or if clear it may not be free of pathogenic cysts. The cost of water treatment is small, around 0.25% of a household's current budget. Benefits of water treatment include the removal of clay which causes turbidity and harbours virus and bacteria, and of the organic molecules causing colour which hinder disinfection, and of algae, iron and manganese. Also water corrosivity can be corrected. Modern Australian treatment processes are well-understood and cost-effective, but ultra-conservatism in design has at times added to the costs of plants. The systems of government subsidy have not generally encouraged close design to minimise plant size nor the use of high rate processes. Such encouragement is seen as needed in the present economic climate.

A.G. Strom

J. A. Crockett

Alan Strom is a Director of Gutteridge Haskins and Davey and is responsible for all aspects of water technology within that firm. He has been involved in designing and building water treatment plants for 35 years and has been responsible for introducing many innovations. Jonathan Crockett is a Principal of Gutteridge Haskins and Davey. He is responsible for water quality and process aspects of the investigation, design and commissioning of water and wastewater treatment plants designed by the firm .

INTRODUCTION Water is the only commodity ingested by people direct from the bulk supply often without treatment. Other foodstuffs are carefully packaged, pasteurised, sterilized, subject to strict quality and health controls or cooked before being ingested. Proven cases of transmission of disease by the water route in Australia are few but the suspicion is that there are many more minor cases which are attributed to other causes or are unrecorded. While we have high standards of public health and sewage treatment, a lack of serious endemic diseases, and generally low population densities in our catchments, we must still ensure that drinking water is properly disinfected and , in the Authors' view, to achieve this the water must firstly be clean, and secondly, free of pathogenic chlorine-resistant cysts, spores and ova. Disinfection of turbid, coloured water by chlorination alone cannot be assumed to be fully effective even if it does achieve zero counts of indicator bacteria. The true cost of providing water to consumers in Australia ranges between 20 and 80 cents per kL with the cost of most expansions or new systems in the upper half of this range . Provision of full water treatment generally costs between 10 and 20 cents/ kL. A typical household in Australia uses between 400 and 900 kL of water per year and pays water rates of between $150 and $300 per year, or perhaps 1OJo of the current average household expenditure. Proper treatment therefore costs only about 0.25% of current average household expenditure. In view of the ease and relatively minor cost of treating water, water supply professionals have a public duty to press for improving water quality. Indeed, should we fail to do this, we could leave ourselves open to adverse public reaction and even legal action in the event of a serious outbreak of waterborne disease.

ficulty of disinfection by increasing the demand for disinfecting chemicals and absorbing ultraviolet light and, in the case of chlorination, colour can result in the formation of trihalomethanes such as chloroform which are suspected human carcinogens. Hence there is a world-wide trend (with different emphasis certainly from country to country) to ,remove colour from highly to moderately coloured waters before chlorination, or to adopt options other than chlorination (see under Disinfection). Colour and other dissolved organics, particularly if they have been ozonated or chlorinated can provide a food source for heterotrophic organisms in reticulation systems. Thus, as well as permitting safer and easier disinfection by chlorination, removal of colour and organics by water treatment reduces the extent of reticulation growths which can lead to taste, odour and staining problems . Similarly water treatment removes algae, which may be a periodic problem when water is stored. Apart from the development of foul tastes and odours, dead algae collect in reticulation mains and add to the food for micro-organisms there, so contributing to the black sludge in dead-ends and the 'dirty water' experiences. Correction of pH and alkalinity to reduce corrosion is an important benefit of water treatment as it may save substantial expenditure on reticulation maintenance and household plumbing. Iron and manganese, which can be serious nuisances in reticulation systems and supply mains, are removed by water treatment, easily in the case of iron, but manganese can be difficult and requiring of chemical oxidation. Prior reservoir aeration helps in their removal.

TECHNOLOGY OF WATER TREATMENT BENEFITS OF WATER TREATMENT As well as improving the appearance of water, removal of turbidity by water treatment results in the removal of almost all cysts, spores, ova, bacteria and virus, and importantly increases the effectiveness of chemical or ultraviolet disinfection, since turbidity particles, with their coating of adsorbed organics,. both add to the demand for dinsinfecting chemical and shield viruses and (to a lesser extent) bacteria from the disinfecting agent. Furthermore, removal of turbidity helps to eliminate the deposition of sludge deposits in reticulation mains, which are a major cause of 'dirty water' complaints from consumers. Colour, caused by large organic molecules derived from plant lignin, is partly an aesthetic problem but it also adds to the dif30

WATER December, 1987

The major options for water treatment processes (other than for softening or desalination) are briefly reviewed and their appropriateness for removing particular pollutants are summarised in Table 1. First-stage processes include: reservoir aeration for iron, manganese and algae control; copper sulphate dosing for control of algae; screening for removal of debris; micro-screening for removal of large algae; and dosing of coagulants direct to a water storage. These processes may help with a particular water quality problem but are never full solutions. Full removal of naturally occurring turbidity or colour, together with most bacteria, virus and algae, can only be achieved by chemical coagulation. The only new development in coagula-


TABLE Appropriateness of Water Treatment Processes in Removing Pollutants

. >

0

Water Treatment Process

., -~

.,

1n >, u

2

.

>

<

oil

Q)

.

0

"'

Slow Sand FIitration

g

g

Coagu lation sedi mentation , filtration

g

g

Q)

Cl

,,~ f:,

., ., ., ;; ., 0 'E -., ,, 0 0

., Q) Q)

oil

~

Q):,

...

u

g

g

~o

C:

Q)

C:

.

J::

oil~

ON

C: C:

u

!:: :;

g

g

Direct filtration ¡ Dissolved air flotation without filtration

g

g

g

g

g

g

g

g

g

g

g

g

g

g

.,

g

g

Base excha ng e softening Slrofloc

~

;;;

g g

g

..

g

Aeration Lime Softening and filtration

0

g

g

Activated carbon Adsorption

g

g

g

Mlcrostralnlng

mechanical solids-contact clarifiers iuch as the Infilco 'Accelator', Degremont's 'Pulsator' and 'Super Pulsator'. (a 'Pulsator' with inclined plates added) and PCI's flat-bottom clarifier. There are examples of most of these in Australia, several being operated successfully alone with the addition of filters to follow as a future stage - a possible staging strategy to consider. Dissolved air flotation (DAF) has been applied for removal of floes in water treatment only for the past 15 years. The principal advantages of flotation over sedimentation are that typically light, and difficult-to-settle colour and algae floes can be more completely removed, and at a high rate (10-12 m/ hr). Turbidity consistently between 1 and 1.5 NTU can be achieved without use of flocculation aids. The only disadvantage of DAF is that operating costs are higher due to higher power costs for pumping the high pressure recycle. For example, a recently constructed DAF plaht with filters in Tasmania consumes about 0. 12 kW hr/ kL treated, compared to 0.08 kW hr/ ' L for a neighbouring new plant with a solids contact clarifier and filters. However, the capital cost of DAF can be substantially lower than for other sorts of clarifiers, especially if the DAF zone is included in the same tank as the filter. This advantage more than compensates for the higher power cost and is the reason why probably the majority of plants being built at present use the DAF process, or can be readily adapted to do so. As an example of this latter, Figure 1 shows cross section of the 50 ML/ d plant now under construction at Wodonga (Vic .). It is a direct filtration plant (see below) but is designed to facilitate possible future conversion, should algal blooms increase, to DAF by adding flocculation, and the DAF process above the filters. This Figure shows the compact arrangement possible with DAF.

Domestic fi lters Ozonatlon

g

Chlorination

g

Chlorine dioxide

g

g

g

FUTURE FLOCCULATION CHAMBER INLET CHANNEL

7,--

,,,,

Chloramlnatlon

11

Ultraviolet

1,

:1

II

g

Good,

Fair,

poor, or no effect

II

1,

ti

~~.::=:.-

tion in the past 15 years (apart from new chemical coagulants suited to particular cases) is the Australian Siroflox process using magnetite. Most often however, coagulation and flocculation with alum or ferric salts, aided by polyelectrolytes or activated silica, will usually be found the most appropriate process. Coagulation involves both careful control of chemical doses and pH, and careful control of mixing intensity and reaction time as it is a fast process. Flocculation, the agglomeration of neutralised particles, is relatively slow and the mi~¡ing intensity and flocculation time necessary must be controlled to allow building of floes by particle collisions to sizes which are easily removable in the next step, the solids separation process, in which most process differences are to be found. Sedimentation in horizontal or circular clarifers, while one of the oldest and simplest methods, is also the most costly and least efficient. It is only appropriate where the turbidity is very high (200 or more) or where there are high loads of readily-settled silt and it is essential to draw on the raw water source water at these times. Space requirements are considerable as hydraulic loading rates are low, but turbidity removal is reasonable and water consistently under about 5 NTU can be achieved at the lower end of these loading rates. Space can be saved by use of tube or plate settlers which allow loading rates up to 5-8 m/ hr. Several sizeable tube settler plants have been built in Australia and several simple gravity sedimentation tanks have been successfully up-rated by addition of tube settlers . Sludge Blanket and Solids-Contact Clarification processes take advantage of the improved particle collection efficiency achievable by contacting the dosed water with a very large number of pre-formed floes. They can produce water of low turbidity (under 1 NTU) and some can operate at quite high hydraulic rates of 3-4 m/ hr or higher. They can also handle difficult-to-treat high colour, low turbidity waters when flocculation aids (polyelectrolyte or activated silica) are used . There are several different forms, including the low-rated Candy hopper-bottom sludge blanket clarifier (I to 2 m/ hr),

~l~~~E

::-_-_...:_l

ALUM

j

POL YELECTROL YTE

Figure 1. Direct filtration with provision for future in-filter

DAF. Granular media filtration is generally used as the final polishing step to remove carry-over floes from a clarifier so as to give a water with turbidity below 0.5 NTU. When well-designed and operated, turbidities under 0.2 NTU can be achieved if desirecl,. Filtration is desirable in any treatment plant as it is a positive barrier to the passage of most bacteria and virus, and more importantly cysts and ova. Filtration also virtually eliminates the deposition of debris in reticulation systems . The process of direct filtration can take various forms, including simple filtration without chemical addition (which will not remove very much colour or turbidity); formation by standard flocculating procedures of a floe which is then removed in filters having relatively coarse media; and formation of a microfloc only, prior to filtration. This last process, known as contact filtration in the USA, has the advantage that it saves the cost of flocculation and uses substantially less chemical than the second type (or full treatment) where a large floe must be formed. It can provide complete treatment at about 75% of the capital cost of a full water treatment plant, and at a lower operating cost. There are now five direct filtration plants of the contact form totalling 325 ML/d built or building in Australia today, and another of 130 ML/d is proposed . While direct filtration is not applicable for all waters , it is eminently suited for stored waters or dry-season water having turbidity and generally colour below 20 NTU and 30 Hazen respectively. Its adoption for dry weather conditions by many existing plants including some large ones could afford operational savings and provide the most economical means of increasing capacity. There has recently been increased interest in slow sand filtration, mainly in Victoria. This process, using loading rates up to 0.5 m/ hr (about one twentieth of conventional rapid filtration), WATER December, 1987

31


can remove sediment and most algae and, most importantly, is effective in removing most micro-organisms. Some reduction in colour and turbidity occurs by adsorption into the biofilm on the sand grains. It is not a full treatment process but offers for certai'n low colour and turbidity waters an alternative means of partial treatment and disinfection without resort to chlorination . The Australian development of Sirofloc has the potential particularly for highly-coloured acidic waters which are difficult to treat with alum . It can provide a better quality water than other forms of clarifier at a higher loading rate (10 m/ hr). Unfortunately the high cost of caustic soda in Australia makes it more costly to operate here than conventional coagu lation, however the process is doing well overseas. It is a process worthy of evaluatio n for all waters.

/

II II J

V 10.0 /

., ~

".;

Vv

~

:;:c

I-

1. 0

WHAT ABOUT THE COST?

The Oversized Plant There is often another diseconomy hidden in the plant's nominal capacity. A common practice, encouraged by wellintentioned government subsidies, has been to provide for a toohigh plant capacity when the plant is built. Consider an all too frequent appoach: • current peak daily demand is around 20 ML/d (say) but we should allow for 22 as we don't have records for the driest year. • 20 years is less a reasonable design period. • current population growth is 2% which we will assume will continue for 10 years then taper off to I % for the subsequent 10. • we should allow for a 10% increase in per-capita consumption. • the old chestnut of allowing for only 20 hours per day operation out of the 24 for something as costly as a water treatment plant. 32

WATER December, 1987

I,< 1/t,.,t,.,

/

/

/

'/ ./

/

Capital costs of a range of water treatment plants of various capacities are shown in Figure 2. It can be seen that the cost for a particular rated capacity varies widely, up to 130% . This variation plant to plant relates largely to more or less conservative design parameters, as well as the standard of ancilliaries such as buildings, standby equipment and siteworks. The plants fa ll roughly into two bands, one containing conventional plants including both clarifiers and filters, and the other clarifier-only direct filtration and Sirofloc plants. But there is a wide variation within these bands. Some of the higher costs may be due to the need to cope with extremely turbid water in the wet season. But, around Australia examples can be found of the adoption of clarifiers and filters when direct filtration wo uld have cost less and worked better, also of dissolved air flotation, while the most appropriate process, being eschewed because of its newness or fancied operational difficulties; or again, of reluctance to adopt the full benefits of polyelectrolytes or dual media filters .

/

t,.,

* . * • rl'1/ * / .;, V* l7 /

I-

/

/

DISINFECTION Chlorination is and will remain the most common disinfection method because of its low cost, simplicity and rapid effectiveness. Other options such as use of chlorine dioxide or chlo ramination, or slow sand filtration, can be of interest as they avoid formation of trihalomethanes and tastes and odour, and, in the case of chlo ramination, provide a long-lasting residual which can limit recontamination in open service basins . Chlorine dioxide is costly, but as well as disinfection it is effective in oxidising algal taste and odour and reduced manganese. Ozonation, which is popular in Europe, has not been used to the Authors' knowledge on a municipal water supply in Australia . While it offers the advantages of more rapid kill of virus, avoidance of THM formation, reduction of colour, and oxidation of manganese, the high capital cost of equipment and lack of residual effect have discouraged its use. Both chlorination and ozonation of raw water, by breaking down large organic molecules, produce more readily assimilable carbon which can provide increased food for heterotrophs in the reticulation mains. Ultraviolet disinfection is being increasingly used in remote areas or on individual major consumers supplies such as at the point of use throughout hospitals and for hotels and mine sites. It is effective if the water is clear and colourless, provided the units are adequately sized and properly maintained.

....

**

t,Yv 0. 1

V

,, /

0.1

10

100

1000

NOMINAL CAPACITY (Ml / d)

• Clarification / Filtration Plants

* Clarifier-only, Direct Filtration, Sirofloc Plant Figure 2. Capital costs of water treatment plants.

Combining these together gives a required design capacity of 38 ML/d, that is 190% of the present peak daily demand which occurs on perhaps IO days per year , and at least 400% of the present average demand. For an outlet from a reservoir, or a tunnel, or siphon under a river, it might be good practice to adopt all these assumptions, but with treatment plants it is poor economics, unless the plant cannot be staged. Staging is often not easy with certain processes or for a small plant and has been unpopular with subsidy providers wanting the 'one bite at the cherry' . Thus for our hypothetical plant, the ultimate may well , be built now. Compounding the problem, relatively conservative process design parameters may be specified, resulting in larger tanks, just in case the more difficult water of the wet season should by some meteorological quirk happen at th) peak of the dry season demand when the water is usually warm and easy to treat. _So our plant finally costs perhaps $M2 more than would really suffice for the present time . Such overdesign is fine if funds are readily available to build it, then it may be termed 'visionary' or 'farsighted', but it would appear to be out of step with the present economic climate. It would appear better now to direct the money available to as many water treatment plants as possible and thus effect the maximum degree of water quality improvement.

A Suggested Approach to a Plant To achieve lowest cost plant still able to perform satisfactorily, the authors suggest the approach involve the following considerations: • are works at the water source practicable which will control raw water quality so as to simplify treatment, including perhaps better catchment management, erosion control, and reservoir aeration? • on how many days of the year will peak demand occur and can it be moderated by restrictions or public education? • the plant design should permit capacity and hence cost to be staged by adding units or, perhaps by accepting partial treatment initially (a clarifier only, now, filters added later), or by later adding rate-increasing technology (tubes or plates, coal on sand filters, etc) . • during peak demand what is the raw water quality? If the mix of treated and raw water gives proper disinfection does it matter if some raw water is bypassed during periods of peak demand? Bypassing can enhance staging possibilities. It of course would be unacceptable from a contaminated river source because of possible transference of cysts, etc. • in small schemes is a dual-pipe dual-quality system feasib le? • where is the most economic location for the plant? Often the most complex question for the engineer to answer. Options may be increased by the emergence of direct filtration by pressure filters as an economic treatment form. CONTINUED ON PAGE 37


THE QUALITY OF WATER IS NOT STRAINED J. R. L. Forsyth ABSTRACT The relevant criteria of water quality must differ with different usages. However , everyone is affected by the quality of water for domestic use. The transmission of a wide range of infective diseases by drinking water has been fully documented. Despite imperfections, the concept of using E. coli and 'coliforms' as indicators of faecal pollution remains valid. Loosening of the permitted levels of indicator organisms reduces the margins of safety to consumers. Inconsistencies in the association between the presence of indicator organisms and water-borne disease have logical explanations.

INTRODUCTION All readers will be concerned, in some way, with the supply or ·the disposal of water - because otherwise you would not be members of the Association. You will undoubtedly have considered at times why you go to the trouble of supplying water - apart from the prosaic facts of trying to keep the breakfast on the table and to keep one' s sense of achievement more or less intact. There are many reasons. For example, you could be involved in collecting, storing and distributing water for irrigation purposes. The Romans, on the other hand, went to an enormous amount of trouble (and demonstrated staggering skills in engineering in the process) to supply water for, among other purposes, the filling of the Colosseum in order to stage naval battles. Perhaps, you may be principally involved in the supply of water for industry and here the types of usage themselves vary enormously. All of us are, however, concerned with the supply of water for human domestic use - and the word 'concerned' here can have rather different meanings. In all these different usages the questions both of quantity and quality intrude . The criteria of quality vary vastly for different purposes. In this sense one is reminded of the story of the seven blind philosophers and the elephant - each held on a different part and described the elephant in entirely different and contradictory terms. The things which we make a fuss about are the things which we consider important and which we lack. There is the old chestnut about the haughty imperial German officer regarding the captured Serbian soldier with disdain. "What are you fighting for, peasant?" "Bread, sir", came the answer, with the addition, "And for what does your highness fight?" " I fight for honour, fool!" "Ah yes sir, all men fight for what they lack!" You will hardly be surprised that a medical person will be most interested in the issue of water supply as an essential part of healthy living. Of course, even within the medical field water of greatly different types is needed . The surgeon may think of water as something with which to wash his gloved hands during an operation - and sterility and warmth are essential qualities. Another may want water to be pyrogen-free and suitable for inoculation. Yet a third may need a fluid with which to dilute whisky.

WATER AND DISEASE On the broader scene, however, the connection between water supply and health was recognized a very long time ago as is illustrated by the writings of Hippocrates' in his discourse "On Airs, Waters and Places" in which the proper .student of medicine is adjured to take note of the source and quahty of the water supply of the population being observed. Naturally, the association between water and health covers a very large range of situations. Only a few of these can even be touched on in a short paper. Just to illustrate, one can briefly remind the reader that the chemical content of water can give rise to acute illness as with copper, to chronic illness as with arsenic or lead and, indeed, to health and disease as with differing concentrations of fluoride and, possibly, with varying levels of hardness. 34

WATER December, 1987

Dr. Jocelyn Forsyth is Director of the Microbiological Diagn ostic Unit, Department of Microbiology, University of Melbourne where he has held this position since 1977. He was Asst. Director from 1968 and during the preceding four years, Lecturer and Senior Lecturer in the Department of Microbiology, Monash University, Victoria. <II

J. R. L. Forsyth

In the circumstances, however, a medical microbiologist can be excused for concentrating upon the issue of infective disease, and, at least to begin ·with, on some of the more direct aspects. It is difficult to appreciate now that in the first half of the 19th Century - and indeed throughout the whole of the century there was a struggle between those who advocated the concept of contagious disease and those who opposed it. It is also strange to realise that the opponents of the 'contagion' hypothesis often were inspired by the highest of motives and the most liberated of thoughts2 • Nevertheless, long before the discovery of bacteria - let alone viruses - as causes of disease certain acute observers had noticed that there was a direct association between water supply and serious disease. The first of these was William Budd, a physician of Bristol. Many years before he published his book 3 on typhoid fever he had noticed how the disease could be spread downstream from one set of dwellings to others which abstracted water from a creek even when the inhabitants of the second group had no other contact ' with those initially infected. He had seen how an unsatisfactory hygienic situation could exist for many years without disease occurring until a case, excreting the specific pathogen, was introduced into this environment and only then did an outbreak ens'ue . Budd described in detail how of a row of households - the Richmond Terrace - in only those which took water from a contaminated well did anyone become the victim of typhoid. Because of the essentially more dramatic nature of the epidemic disease, cholera, than the then endemic disease, typhoid, as well as because of the scope and precision of his investigations, John Snow was the prince of these early epidemiologists. Snow followed the fortunes of the customers of two London water companies• with overlapping areas of distribution - a factor which served to create a controlled experiment - through two cholera epidemics and showed the association of this disease with the quality of the source water in each case. Of the two companies, the Lambeth company conveniently changed its source of water between the epidemics to make the point. Although Snow's findings eventually caused all London water derived from the river Thames to be filtered before entering supply• his arguments were not convincing to all, apparently, even at the end of the century. This was shown by the notorious row in Hamburg where the findings of Robert Koch, the famous German pioneer in medical bacteriology, were vehemently disputed. Here the city of Hamburg on the river Elbe was stricken with cholera with a heavy mortality. The satellite city of Altona drew its water from the Elbe, downstream of Hamburg. An enormous outbreak would have been expected in Altona but the city's inhabitants were protected by the fact that the water was filtered and protected until person-to-person spread occurred much later in the outbreak•. Koch was also able to show how outbreaks of typhoid in Altona were associated, in time, with failures in the filter beds which protected the city's water supplies' . Nowadays the place of infective organisms as a cause of disease is well established and a great list of pathogenic organisms have been shown to be able to be spread by the water route. The vast majority are derived in most part from the gut of man or other animals. If we look at a selection of these - whether bacterial, or viral or protozoa! in nature - one sees that there is a common


TABLE 1. SOME INFECTIVE AGENTS WHICH HAVE BEEN TRANSMITTED TO MAN THROUGH THE MEDIUM OF DRINKING WATER BACTERIAL

VIRAL

PROTOZOAL

Salmonella typh,• Salmonella spp. • Shigella spp. ' 0 Vibrio cholerae" Diarrhoeagenic £. coli" Campylobacter jejuni"

Hepatitis A" Rotavirus 15 Norwalk agent " Non-A, non-8 Hepatitis"

Giardia lamblia" £ . histoly tica" Cryptosporidium' 0

thread. The vast majority are derived in most part from the gut of man or other animals. (Table I)

Difficulties in testing for hazards If one followed this it is clear, as far as infective disease is concerned, that if one could ensure a supply of drinking water without these pathogenic or disease-causing organisms the population could drink it without fear. Therefore, if one could test the water to be sure that these . things are absent - it would appear that all should be well. Unfortunately, it does not turn out quite like that - and for a number of different reasons. I. There are a lot of different pathogens. To test for different pathogens needs a whole range of totally different techniques. 2. The techniques available are uneven in quality and sensitivity - many are well below the level of sensitivity needed and some are not available - at any acceptable price. 3. The very fact that the list of known pathogens is so long and that some have been recently added indicates that 'new' organisms of significant potential are continuing to be discovered and new tests and procedures would have to be developed and employed for each - if that was possible or affordable - and it is often impossible. The short answer is that testing for pathogens as a routine surveillance system is not on the cards at present and may never be. The alternative is to look for indicators of pollution and it follows from earlier statements that the logical thing to do is to look for indicators of intestinal pollution. The first person to put this concept on a sound footing was Alexander Houston of the Metropolitan Water Board, London. In his experiments" he characterised what was then known as Bacterium coli (now Escherichia colt) and noted the tendency of this organism to disappear outside the body in natural water. He drew parallels between the numbers of Bacterium coli in polluted sources and those of typhoid bacilli. Further, he and other workers 22 have shown to what degree Bacterium coli and similar but not identical organisms were specific indicators of faecal pollution . The peculiarities of microbiologists and of their nomenclature have tended to confuse people over the years - and other microbiologists as well . The problem has been compounded by the fact that water microbiologists have to use simple and quick methods in order to screen large numbers of specimens. In addition, the earlier workers, who tended to establish names, were limited by the range of techniques and the knowledge of taxonomic principles which were available at the time. The terms 'Escherichia coli', 'faecal coliform' and 'coliform' will be all too familiar to you. 'E. coli' represents a particular species of bacteria which can be rigorously or less rigorously defined. The less rigour, the less certainty that the definition will be right. 'Faecal coliform' is a less rigorous definition but suited to membrane filtration techniques by the water bacteriologist. Most of the bacteria thus defined will be E. coli - but not all. 'Coliform' or, E. coli-like, is a still less rigorous definition.

The place of 'coliforms' as indicators If the bacteria which are defined as 'coliforms' are strictly identified it is shown that a whole range of different organisms is present. Some will be E. coli but others not. The nature of the mix will vary from one sampling point and circumstance to another. A fairly recent description by Colwell's team 23 listed, inter alia, the following genera: Acinetobacter, Aeromonas, Chromo-

bacterium, Citrobacter, Enterobacter, Erwinia, Escherichia, Hafnia, Klebsiel/a, Serratia - all presenting as 'coliforms'.

So, whatever 'coliforms' might be they ilo not necessarily come from the gut - although all these above can do so. They could come from the environment - unassociated with man or animals (but to a variable extent). It can, therefore, be argued that coliforms do not matter and that their presence in water is irrelevant to questions of health and disease. That argument ignores the facts. It is well known that the principle behind biological waste water treatment is to accelerate the natural processes of purification. If one examines a creek at intervals downstream of a point of pollution by sewage effluent the earliest samples tested show huge numbers of E. coli. These numbers decline with successive samples and increasing distance from the point of pollution but the numbers of 'coliforms' stay up. Eventually, these numbers also decline but the total counts, as measured by standard techniques, remai high. Last of all these also decline. Therefore, 'coliforms' can constitute evidence of previous contamination by sewage. it is perfectly possible for pathogens to survive in water longer than E. coli and to parallel the 'coliforms' in their capacity for survival.

The limitations of the use of indicator organisms in testing The scenario which has been painted permits a number of irritating complications . Firstly,' it is clearly possible to have indicators in water which is not dangerous to drink - for more than one reason. Secondly, it is possible to have outbreaks in the apparent absence of indicators. The Riverside outbreak 9 is one of three outbreaks of salmonellosis spread by water from which indicator organisms seemed to be absent. It must be pointed out, however, that in those systems which are most likely to be prone to outbreaks the standard and completeness of surveillance is the least likely to be of high standard. Because of the fact that different organisms also may have different susceptibilities to disinfection it is also perfectly possible to conceive of situations where the indicators have been destroyed and where pathogens remain. This is certai,nly the case with giardiasis' " in which the cysts are relatively resistant to chlorination (although very susceptible to filtration because of their size). This inevitably raises the spectre of viruses. The outbreak described by Neefe and Stokes 14 shq.wed how hepatitis A could be spread by water and further experiments by this team 24 showed that simple chlorination was relatively ineffective at inactivating the viruses. This was done by experimenting with volunteers drawn from Conscientious Objectors in World War II who refused to fight but were prepared to serve medical science in this selfless way . Much of the same was shown by the huge outbreak of non-A, non-B hepatitis in New Delhi 25 · 26 , although whether indicator organisms were absent or not is far from sure from the published description. It is, perhaps, worthwhile pointing out that Neefe and his colleagues27 showed that chlorination was perfectly effective in protecting against hepatitis A once the water was coagulated and filtered. In addition, outbreaks of rotavirus gastro-enteritis spread by water have been described "· 2 8 • While Mosley's review 29 failed to show that virus disease other than hepatitis and gastro-enteritis were actually spread by water, Chang and Shuva13°·3 ' have raised the possibility of conventional water treatment failing to remove viruses and disease thus being seeded or dropped into the community - thus sustaining virus diseases in it. This is a nasty idea . Does it mean that we should stop testing for coliforms and similar things and concentrate on testing for viruses - and for which viruses should we test? Gamble, for one, disputes this and showed 32 that the application of techniques for getting rid of viruses from water have not shown a commensurate reduction of virus disease beyond that produced by conventional treatment of water to meet conventional criteria based on indicator bacteria. The 'take home' message would appear to be that despite mountains of words and forests of print from symposia and conferences, the concept of E. coli as more specific and of coliforms as more sensitive indicators of pollution of intestinal origin still holds up. Its usefulness has been proven again and again even though its imperfections have been shown and are acknowledged. WATE R December, 1987 35


THE PAUCITY OF EPIDEMIOLOGICAL DATA The high threshold of detection The proof of the pudding is said to be in the tasting. It is now acknowledged that the standard of water in much of rural Victoria is or has been poor - using the presence of E. coli etc . as the criterion. W hy then, it may be asked, are the people of these towns not yellow coloured from the jaundice of hepatitis? Why are they not anchored to the dunny? Demonstrate the outbreaks commensurate with the poverty of water around Victoria. Why does a fail ure of water not become immediately manifest in disease? In dealing with these questions the point has to be made that the threshold of detection of water-borne illness is quite high . A lot can happen before such illness becomes obvious in the community. There are a number of reasons for this: 1. Parts of the resident population may be immune from earlier experience and it is only when tourists come - as to Mexico that they suffer from the prevailing microbes. 2. Infection does not equate to disease. Subclinical infection is very common and this is particularly marked with viral disease . 3. Diagnosis is imperfect. 4. Notification is imperfect. 5. Investigation is delayed and imperfect. There is a classical diagram which looks something like a series of rectangles of reducing size included within each other and demonstrating the distribution of illness in the community.

Total illness

Illness leading _ 10 minor action

Illness investigated turther

,___

r-

.,__ _ _ _ ___.___ _ _~--~__.__....

Admissions to hospital Admissions to - teaching hospitals

Illness in the community and its recognition.

The area of the outer zone shows total illness. The next zone shows illness about which something is done buy something at the chemist, see doctor. T he next shows illness which is investigated as to its aetiology and, possibly , source. The next shows cases admitted to hospital. ¡T he next - if there is one - shows the cases admitted to the teaching hospitals - about which the articles for journals are

written. That is, a minute fraction of illness is intensively investigated and the results publicized. This is particularly so with minor symptoms which, nevertheless, contribute to substantial morbidity and economic cost to the community when days off are added together . With variations, this diagram has been shown to be common to all countries . It highlights the potential insensitivity of passive epidemiology. It makes it very difficult to carry out investigations into the source - especially if one is thinking about a transient phenomenon like the failure of a water supply. Take the episode of the salmonellas in the salame some years ago. First, undue numbers of a particular salmonella isolated from sick people were sent to our laboratory for identification. Second, Health Commission officers had to look at where the patients lived and then to interview them - what had they eaten, what was common? F irst answer - nothing appeared in common! 36

WATER December, /987

T hird , one couple said that they had ha'l salame and preserved scallops and that one pot of scallops were unopened . Salmonellas were found in the 'unopened' scallops - therefore the scallop bottling factory was investigated and the possibility of pollution of scallop fishing areas was considered. Fourth, a couple who had eaten salami but no scallops and actually had some salame left over presented with illness . T hen suspicion could be shifted to the salame but only when salmonellas could be isolated in quantity from the uncontaminated interior of the salame could the case be regarded as firm. In summary then, there were numerous delays and false trails - all factors which lead to difficulties and to an insensitivity of the investigative process. , Remember, the sources of most of the hundreds of cases of salmonellosis in Melbourne each year are never traced .

The paradox of the infectious dose If one wants to test the virulence or infectivity of strains of pathogenic bacteria one looks for the dose which will cause symptoms in 50% of the recipients - the ID (Infectious Dose) 50% . When experiments on volunteers were done with typhoid it was found that the ID 50 was very high 33 . How can such a disease be spread by water? What sort of water will they be drinking to cause typhoid? Then look at the observed facts. The classical Croydon outbreak34 comprised 322 primary cases of typhoid in the population, but, a population of 30 000 to 40 000 was exposed. That is, an ID! One explanation is provided by certain calculations which have suggested that a small minority, about I%, of persons are highly susceptible - to one to two typhoid bacilli 35 . An attempt has been made to point out some of the problems facing the establishment of criteria of water safety. When WHO set the zero guidelines for E. co li and coliforms it was just not a gesture of spite to engineers who have to cope with imperfect treatment plants, imperfect ~eservoirs, imperfect reticulations and imperfect humanity. They might have been reflecting on Craun's finding of coliforms in association with so many A merican outbreaks of waterborne disease36 . In epidemiology, we cannot tak~ our experimental beams or structural elements into a testing faboratory and test them to destruction, if need be, and then calculate the stresses and the dimensions and add a suitable percentage in our designs for a safety margin . The radiation scientists can make a 'guesstimate' that the radiation released from Chernobyl may give rise to an extra 1 000 cancer deaths in Europe. Epidemiologists cannot say that x E. co li per JOO ml will give rise to y cases of diarrhoea and z of hepatitis. They can say that, if there are coliforms in the water coming from a tap, it may mean faecal pollution by man or animal and if you raise the threshold of action you are decreasing your margins of safety and are producing a smokescreen so you cannot see what is happening in your supply . They can also point out that the difference between pollution by animal and human faeces is only quantitative, not qualitative. Salmonellas, campylobacters, yersinias, giardias, crytosporidia and possibly even some rotaviruses 3' can come from animals and are pathogenic for humans too. Besides, bovine faeces is bad enough to listen to . Who wants to drink it?

REFERENCES I. Hippocrates (1938). On airs, waters and places. Med. Classics. 3: 19-42. 2. Ackerknecht , E. H. (1948). Anticontagionism bet ween 1821 and 1867. Bull. Hist. Med. 22: 562-93. 3. Budd, W. (1873). 'Typ hoid Fever: its Nature, Mode of Spreading and Prevention' . Longman Green, London . 4. Snow, J. (1 935, 1965). 'Snow on cholera'. Hafner, New York. 5. Richards, T. (1983). Farr sighted . Br. Med. J. 286: 1736-7. 6. Duncan , G. (tra nslator). (1984). 'Professor Koch on cholera' . David Douglas, Edinburgh . 7. Koch , R. (1 896). Statistik der choleraepidemic in Hamburg in herbst 1892 und winter 1892/ 93 . Arb. Ka iserlichen Gesundheitsampte. 10 (unlage 2): 22-52 . 8. Budd , W. (1856) . On the fe ver at the Clergy Orphan Asylum. Lancet. ii, 617- 19.


9. Greenberg, A. E. , Ongerth, H.J . (1966). Salmonellosis in Riverside, Calif. Am. Water Work Assn. J. 52: 165-74. 10. Ross, A. I., Gillespie, E. H. (1952). An outbreak of water-borne gastro-enteritis and Sonne dysentery. Mon. Bull. Min. Hlth. and P.H.L .S. 11 : 36-46. 11. Levine, R. J. , Nalin, D. R. (1976). Cholera in primarily waterborne in Bangladesh. Lancet. ii: 1305. 12. Rosenberg, M. L., Koplan, J.P ., Wachsmuth, I. K., Wells, J. G., Gangarosa, E. J., Geurrant, R. L., Sack, D. A. (1977). Epidemic diarrhea at Crater Lake from enterotoxigenic Escherichia coli. Ann. Intern . Med. 86: 7 14-8. 13. Vogt, R. L., Sours, H. E., Barrett, T., Feldman, R . A., Dickinson, R. J., Whitherell, L. (1982) . Campylobacter enteritis associated with contaminated water . Ann. Intern. Med. 96: 292-6. 14. Neefe, J. R., Stokes, J. Jr. (1945). An epidemic of infectious hepatitis apparently due to a water-borne agent. JAMA. 128: 1063-75. 15 . Hopkins, R. S., Gaspard, G. B. , Williams, F. P. , Karlin, R. J., Cukor, G., Blacklow, N. R. (1984). A community water-borne gastroenteritis outbreak: evidence for rotavirus as the agent. Am. J. Pub/. Hlth . 74: 263-5. 16. Taylor, J. W ., Gary, G. W., Greenberg, H. B. (1981). Norwalk-related viral gastroenteritis due to contaminated drinking water. Am. J. Epidemiol. 114: 584-92. 17. Khuroo, M. S. (1980) . Study of an epidemic of non-A, non-B hepatitis: possibility of another human hepatitis virus distinct from post-transfusion nonA, non-B type. Am. J. Med. 68: 818-24. 18. Shaw, P. K., Bordsky, R. E., Lyman, D. 0. et al. (1977). A community-wide outbreak of giardiasis wit h evidence of transmission by a municipal water supply . Ann. Int. Med. 87: 426-32 . 19. Ritchie, L . S., Davis, C. (1948) . Parasitological findings and epidemiological aspects of epidemic amebiasis occurring in occupants of the Mantetsu apartment building, Tokyo, Japan. Am. J. Trop. Med. 28: 803- 16. 20. D'Antonio, R. G., Winn, R. E., Taylor, J.P. ( 1985). A water-borne outbreak of cryptosporidiosis in normal hosts. Ann. Intern. Med. 103: 886-8. 2 1. Houston, A. C . In: Chalmers, A. K. chr. (1912). Discussion on the varieties and significance of B. coli in water supplies. Br. Med. J. ii: 704- 16. 22. Bardsley , D. A. (1934). The distribution and sanitary significance of B. coli, B. lac tis areogenes and intermediate types of coliform bacilli in water, soil, faeces and ice-cream . J . Hyg . (Lond.). 34: 38-68.

23. Austin, B., Hussong, D., Weiner, R. M., Colwell , R.R. (1981). Numerical taxonomy analysis of bacteria isolated from the completed 'most probable numbers' test for coliform bacilli. J. Appl. Bacteriol. 51: 101-12. 24. Neefe, J. R., Stokes, J. Jr., Baty, J.B., Reinhold, J. G. (1945). Disinfection of water containing causative agent of infectious (epidemic) hepatitis. JAMA . 128: 1076-80. 25. Viswanathan, R. (Jan. 1957) . Epidemiology of the outbreak of hepatitis in Delhi (December 1955). ind. J. Med. Res. (Supp . No): 1-29 . 26. Wong, D. C., Purcell, R. H., Sreenivasan, M. A. , Prasad, K. M. (1980). Epidemic and endemic hepatitis in India: evidence for non-A, non-B hepatitis aetiology. Lancet ii: 876-9. 27. Neefe, J. R., Baty, J.B ., Reinhold, J. G., Stokes, J. Jr. (1947). Inactivation of the virus of infectious hepatitis in drinking water. Am. J. Pub. Hlth. 37: 365-72. 28. Lycke, E., Blomberg, J. , Berg, G., Eriksson, A., Madsen, L. (1978). Epidemic acute diarrhoea in adul ts associated with infantile gastroenteritis virus. Lancet. ii: 1056-7. 29. Mosley, J. W. (1967). Transmission of viral diseases by drinking water . In: . Berg, G. ed. 'Transmission of Viruses by the Wate Route'. Interscience, New York. 5-23 . 30. Chang, S. L. (l 986). Water-borne viral infections and their prevention. Bull. WHO. 38: 401 - 14. 31. Shuval, H. I. (1976). Water needs and uses: the increasing burden of enteroviruses on water quality. In : Berg, G. Bodily, H . L., Lennette, E. H., Melnick, J. L., Metcalf, T. G. 'Viruses in Water' . APHA, Washington DC . 12-25 . 32. Gamble, D. R. (1979). Viruses in drinking water: reconsideration of evidence for postulated health hazard and proposals for microbiological standards of purity. Lancet. i: 425-8. 33 . Hornick, R. B., Greisman, S. E. , Woodward, T. E., DuPont, H. L., Dawkins , A. T., Snyder, M . J. (1970). Typhoid fever: pathogenesis and immunologic control (first of two parts). N. Engl. J. Med. 283: 686-91 . 34. Ministry of Health . (1938). Report on a public local inquiry into an outbreak of typ hoid at Croydon in October and November i937. HMSO, London. 35. Kehr, R. W ., Butterfield , C. T . (1943). Notes on the relation between coliforms and enteric pathogens. Pub. Hlth. Rep. 58: 589-607. 36. Craun, G. F. (1978) . Disease outbreaks caused by drinking water. Water Poll. Cont. Fed. J. 50: 1362-74. 37. Eiden, J., Vo nderfecht , S., Yolken, J. H. (1985) . Evidence that a novel rotavirus-like agent of rats can cause gastroenteritis in man. Lancet. ii: 8-11.

A. G. STROM & J. A. CROCKETT Continued from Page 32 â&#x20AC;˘ by careful testing of raw water quality over all seasons, selection of the least costly adequate process(es) and adoption of relatively high process loading rates for the dry weather peak. Can lower capital cost processes such as direct filtration, clarifier only, or Sirofloc, be adopted? â&#x20AC;˘ selection of process and control system design which will minimise operating labour. Full plant utilisation is now possible and necessary and restriction of a plant to 20 hours per day is nonsense.

Implementation Thirty years or more ago, for water treatment plants in Australia, it was often a matter of the engineer calling tenders for a plant to give clean water, and requiring the tenderers to take raw water samples (which might , or might not, be appropriate) and provide the plant complete, or at least the parameters, the working dimensions and the eq uipment. With some waters, this was quite inappropriate, plants could be substantially over-designed, or they required heroic endeavours and agility on the part of the Contractor to produce the stipulated results. This 'Turnkey' approach has recently returned to fashion, the justification being the resulting 'single' responsibility. There is also a misconception that it saves on design costs. While it is true that some Turnkey plants have been installed at a low first cost, others have proved more costly as result of poor specifications. Since the primary consideration in selecting the accepted tender is the first cost, there is a great risk that life-cycle costs will be higher than necessary due to adoption of a poor design of lower-quality with a process which is high in operating and/or maintenance cost. In the Authors' view, implementation of water treatment should be preceded by proper evaluation of water quality and demands and should involve the preparation of a careful concept design, the writing of a clear specification of capacities, design parameters, standards and performances required, and an appropriate division of work between the different specialist con-

tractors. The cost of such an approach is not a major part of the final cost of the works. It gives the most success ful , lowest lifecycle cost plant and makes best use of the knowledge of specialist equipment contractors. Above all , it separates the critical evaluation of water quality and the most suitable process, from the selection of the lowest suitable tenders.

CONCLUSION Proper Water Treatment in Australia is still often regarded as an expensive luxury. This attitude is reinforced by the relatively high cost of many plants. In fact, considering the importance of water to health, well-being and enjoyment of life the cost of properly treating water, perhaps $50 per household per year, is small . We should be far more concerned about providing adequate quality than with avoiding the very moderate costs involved . Disinfection of all water supplies is essential but it becomes an imperfect, costly and consumer-unpopular process when the water is not fully treated. In addition to enabling proper disinfection without consumer reaction, water treatment also removes clay, manganese and iron , and the organic material which feeds growths in the reticulation mains. Proper treatment is the only way to ensure that a safe, palatable and pleasing water can be consistently delivered at the consumers tap. With most raw waters, disinfection without proper treatment is undesirable. Modern treatment processes are efficient and cost-effective provided they are designed and applied with a full understanding of the raw water concerned. Many modern plants have been overdesigned in capacity and process and in the present economic climate this is not satisfactory. Designers should be encouraged to keep costs down by careful investigation, sensible selection of design parameters and by staging the plant, either by adding to it or by uprating processes. Bypassing raw water at peak may well be a perfectly satisfactory and economical staging option if effective disinfection is maintained. A thoughtful approach is the best way to achieve the object of 'low cost' water treatment. WATER December, /987

37


WATER QUALITY MANAGEMENT IN VICTORIA R. A. Graham and R. G. Peck ABSTRACT The Victorian Government employs State Environment Protection Policies (SEPPs) to provide the statutory basis for decisions regarding environment protection and pollution control. SEPPs are prepared by the Environment Protection Authority and released in draft form for public comment before being recommended to Government. Preparation of a SEPP for the inland and coastal waters of the state and implications for the water and wastewater industry are discussed .

INTRODUCTION The Victorian Environment Protection Authority (EPA) was the first state government agency in Australia to be assigned comprehensive responsibilities for pollution control and environmental protection (AEC 1984). Protection of .the land, air and water environments and controls on the effects of wastes and noise were placed under one Act, administered by EPA. The Environment Protection Act 1970 provides for: • works approval and licensing of waste discharges • prosecution for pollution offences • regulations for pollution control and environmental management • formulation of State Environment Protection Policies (SEPPs) and their recommendation to Government for declaration as State Government policy . Whilst the Act covers all wastes, this paper concentrates on water quality management and the development of SEPPs for water. EPA's initial priorities were to address environmental issues of immediate concern to the community. Waste discharges to water were controlled through a licensing system and SEPPs formulated for individual catchments in response to environmental and social needs. To date, the Victorian Government has declared policies for: • Port Phillip Bay (1975) • Western Port Bay and catchment (1979) • La Trobe River catchment (1981) • Western District Lakes (1981) • Lake Colac and catchment (1982) • Lake Burrumbeet and catchment (1983) • Yarra River and tributaries (1984) • Far East Gippsland (1985) • Wimmera River and catchment (1985) These policies specify water quality objectives and provide a framework for systematic and accountable environmental management within these catchments.

THE 'WATERS OF VICTORIA' SEPP The declared SEPPs listed above cover many important water catchments, but major water bodies and more than three quarters of the area of Victoria remain without SEPP coverage (see Figure 1). After consulting representatives of Government agencies, industry, local government, rural interests, water boards and environmental and community groups, EPA decided to develop a single state-wide policy to supplement existing SEPPs.

Rick Graham

Richard Peck

Rick Graham, B.Sc.(Hons.), has been involved in water poffution control for 10 years with the Environment Protection Authority, Victoria. He is now manager - South Metropolitan in EPA 's Operations Division. Prior to joining EPA, Rick worked in the paint and plastics industries. Richard Peck has been with the Victorian Environment Protection Authority since 1982, working on water quality assessment and policy development. Richard has an honours degree in Natural Resource Management and has been involved in this project since 1986.

§ •

DECLARED SEPPs

monitoring site

Figure 1. Water SEPPs and monitoring sites.

• specify indicators to measure and define environmental quality • set environmental quality objectives (where possible) • detail a programme to attain and maintain stated environmental quality objectives . The policy formulation process is outlined in Figure 2.

Definition of the Policy Area The 'Waters of Victoria SEPP' applies to all inland and coastal waters of the state, except where varied by separately declared policies. This approach supplements the detailed coverage of existing policies and establishes a consistent state-wide framework for management of water quality. It incorporates several catchment-specific draft SEPPs which were at an advanced stage of formulation.

Policy Formulation The Environment Protection Act sets out the requirements for SEPP formulation and declaration . This process is discussed with specific reference to preparation of the SEPP 'Waters of Victoria', which was released as a draft for public comment in November 1986 (EPA 1986a). The Act requires that a SEPP: • define the policy area • identify the beneficial uses to be protected 40

WATER December, 1987

Beneficial Uses of the Environment The selection of beneficial uses for protection is the fundamental link between the needs of the community and policy formulation. Community needs are expressed as demands for particular water uses. Each use has established water quality requirements. Policies identify uses to be protected and are a commitment to attain and maintain suitable water quality to protect these uses.


local environmental issues: - waste discharges - land use

Government policies - state conservation strategy & others

community, industry and intra·govemment consultation

~

').-------'..______ pollution control [) costs and benefits I 1

><!::---------.-----'

I

<]beneficial water uses water quality objectives attainment program

public comment period (3 months plus)

I I

I data assessment research policy review

water infonnation management system

comment assessment and policy review recommendation to Government

I

I I

DECLARED POLICY

I \ \

community

, & industry '-

I

I

State & Local Government /

,--------------, environmental quality trends

/

I

I

discharges, land use and activities which iM1uence water quality. The policy recognises the major influence of catchment land use and management on attainable water quality. Improvements in water quality are often required to achieve objectives in waters affected by intensive industrial, urban or agricultural development and major waste discharges. EPA conducts statewide monitoring of water quality to assess SEPP compliance and identify trends and priority areas for action. Sixty-four sites are currently sampled on a fortnightly basis and analysed for a comprehensive range of indicators (see Figure 1) . Results are reported regularly by EPA.

ATTAINMENT PROGRAMME It is important to recognise that SEPPs are not just guidelines for EPA in carrying out its pollution co rol work. SEPPs are State Government policies, and all Government Departments and agencies are required to implement these policies within their areas of responsibility. The attainment programme in the Waters of Victoria SEPP identifies actions necessary for the attainment and maintenance of good water quality. These fall into the categories of point source discharge control, catchment management, non-point (diffuse) source pollution control, and various related activities such as monitoring and research.

Figure 2. The Policy Formulation Process.

The Act defines a beneficial use as 'a use of the environment which is conducive to public benefit, welfare, safety or health and which requires protection from the effects of waste discharges, emission and deposits'. Increasing population and greater quality of life expectations make it more difficult to maintain a balance betwen often conflicting or competing beneficial uses. For example, increased diversion of water for urban supply or irrigation uses may reduce river flows and water quality, threatening other uses such as fish production or recreation. The 'Waters of Victoria SEPP' aims to protect the widest practicable range of beneficial uses of our waters . The quality of potable, agricultural and industrial water supplies are protected where appropriate. Water quality sufficient to allow safe swimming, boating, fishing and protection of aquatic life is to be attained and maintained wherever these uses may be reasonably expected.

Segments of the Environment The policy divides the waters of the state into segments for management purposes. The overall aim is to protect an appropriate range of beneficial uses within each segment. Segment selection involves consideration of a number of factors including distribution of existing beneficial uses , water quality, catchment land use and point source discharges. Inland waters are divided into the aquatic reserves segment, the parks and forests segment and the general surface waters segment. In addition there are separate segments for coastal and estuarine waters.

Water Quality Indicators and Objectives Policies specify water quality objectives in terms of measureable water quality indicators. Examples of quantitative indicators are concentrations of dissolved oxygen, dissolved and suspended solids, nutrients and toxicants, as well as temperature, bacterial numbers and turbidity. Descriptive indicators and objectives are employed for aesthetic objectives such as colour, odour, taste and appearance of waters. The 'Waters of Victoria SEPP' specifies objectives for each segment, based on general criteria for beneficial use protection published by the Authority (EPA 1983a). Segment objectives for each indicator are based on protection of the beneficial use which imposes the most stringent quality requirements, the limiting beneficial use. Protection of potable water supply and maintenance of aquatic ecosystems are the most usual limiting uses. Individual segment objectives take into consideration the level of water quality attainable given good manage~ent of waste

Point Source Pollution Control A high proportion of EPA's resources since its formation in the early 1970s has been devoted to controlling discharges of waste into the environment from individual sources. In the case of wastewater, industrial and sewage treatment plant discharges are controlled by works approval (since 1985) and licensing. As a result there are few major problem discharges of this type compared with 15 years ago. In addition, pollution abatement notices provide a flexible and powerful tool for the prevention of pollution from unlicensed waste discharges or activities adversely affecting environmental quality. There is of course a strong commitment to continued control of point source waste discharges. The 'Waters of Victoria .SEPP' sets the scene for on-going controls, e.nd contains a number of key features. • Waste dischargers shall apply at least a minimum standard of treatment technology, called i;:ommonly available technology (CAT) to wastes prior to discharge to the environment. The policy specifies CAT for some waste types and minimum emission standards in schedules of the policy. Specifically, Schedule D of the policy outlines minimum technology standards for sewage treatment plants, potable water treatment plants, commercial and municipal swimming pools and intensive animal industries, irlcluding feedlots, piggeries and dairy milking sheds. In the case of animal industries, adherence to existing codes of practice is required (Department of Agriculture/EPA 1978, Health Commission of Victoria 1985). These schedules will be progressively expanded to cover other waste types after consultation with affected industries and other interest groups. The minimum emission standards set out in Schedule E of the policy are summarised in Figure 3. • EPA may apply more stringent control technology or emission limits where necessary to protect sensitive environments. An example is sewage treatment, where the minimum requirement (CAT) is secondary treatment for all dischargers except those to ocean waters via extended outfalls, where primary treatment is sufficient. Dischargers to inland waters which offer less than 5: l dilution to the waste discharge may be required to provide tertiary treatment to remove nutrients prior to discharge. An alternative approach is effluent reuse by land irrigation, for which guidelines have been prepared (EPA 1983b). The implications of the policy for the water and wastewater industry are discussed in more detail later. • Minimisation of waste generation, and waste recycling or reuse are encouraged. Some industries may be able to reduce the amount of waste generated and hence waste in need of treatment and disposal, while wastewater reuse on land is a practical and economic disposal option for many sewage treatement and some industrial waste treatment plants. Particularly in drier parts of Victoria, reuse of sewage effluent has become commonplace on WATER December, 1987

41


Indicator

Applicable to

limit

pH Floatable matter

All d ischarges All discharges

range 6.0-9.0 no visible floating oil, foam, grease, scum, litter

Settleable solids (% by vo lume) Heavy metals (g/ m' )

Iron (g/ m') Biochemical Oxygen Demand (5 da y) (g/ m' ) Suspended Solids (g/ m' )

All disc harges (except coasta l) coastal discharges All discharges

co ntaminated stormwat er and coastal d ischarges All other discharges All discharges (except coastal)

Total Residual Chlorine (g/ m' ) Toxicity

annual median less than 0.1 % As-05, Cd-0.1 , Cr-0.3, Cu-0 .2, Pb-0 . 1, Mn-0.5, Hg-0.005, Ni-0 .5, Ag-0.1, Zn-0.5 5.0 g/ m' 2. 0 g/ m' max imum 40 g/ m' annual median 20 g/ m'

All d ischarges (except coastal)

Turbidity (NTU)

or other objectionable floatin g matter. no settleable solids

All discharges (except coastal)

Dry Weather Stormwater maximum maximllm 60 g/ m' median 30 g/ m' maximum 50 NTU median 25 NTU

80 g/ m'

maxim um 100 NTU

All discharges

1.0 g/ m'

All discharges

No acute toxicity using approved tests .

Source: EPA 1986a. Note that these are minimum discharge quality requirements. Higher discharge quality is required where ach ievable using commonly availab le treatment technology or where necessary to meet recei ving water objectives or protect sensitive environments. Schedule D may require higher quality for certain types of discharge.

pasture, tree plantations, golf courses and other recreation areas. Wastewater reuse is an effective water conservation measure as well as being a way of protecting receiving waters from the impact of waste discharges . â&#x20AC;˘ The policy strictly controls or prohibits discharges of waste to potable water supply catchments, to groundwater and to coastal or inland waters of high conservation value . These areas include marine reserves, proclaimed reference areas, coastal mangrove and saltmarsh areas, wetlands and waters in some national or state parks. â&#x20AC;˘ Other issues addressed include construction and location of marine outfalls, source control for toxic and hazardous wastes, prevention and clean-up of oil spills, and methods of wastewater disinfection.

Catchment Management The concept of catchment management to protect both the quality and quantity of our water reso urces has become increasingly accepted in Victoria. The policy recognises the importance of land-use planning in water management, and the need to consider the less tangible water uses such as habitat values and ecosystem protection as well as consumptive water uses . The policy requires that streamflow quality and quantity, lake and wetland replenishment and the needs of aquatic ecosystems be considered in water resource management, including water harvesting and releases from storage. Water conservation is encouraged through increased wastewater reuse and more efficient management of consumptive uses, particularfy irrigation. Benefits include possible delayed construction of storages and the opportunity to allocate water to non-consumptive uses such as environmental flows and recreation. There are many examples in Victoria of inappropriate land-use planning resulting in pollution. In some cases subdivision of land for residential use has been approved without !)roper provision 42

WATER December, 1987

for domestic waste disposal. The polic.y requires responsible authorities to provide new urban subdivisions with reticulated sewerage unless all wastewater generated can be adequately treated and retained within the boundaries of the allotments. Other catchment activities addressed in the policy include river maintenance works, flood plain management , control of adverse effects of recreation activities, and litter control. In this way, the catchment management provisions of the policy emphasise the responsibilities of a number of State and local government agencies .

Diffuse Source Pollution Control The EPA in Victoria, in common with Environmental quality control agencies elsewhere in Australia and overseas, has been generally successful, in controlling point sources of waste discharge to inland waters. In rural and urban areas, diffuse runoff is the major source of pollutants to streams and the main factor limiting improvement of receiving water quality. Accordingly, the emphasis in EPA's water quality protection efforts is changing from point sources to non-point or diffuse sources. These sources can have a more insidious and widespread effect on water quality and are far more difficult and expensive to control. A number of aspects of diffuse source control are addressed in the Waters of Victoria SEPP.

Urban Stormwater Runoff It is well established that the process of urbanisation of a catchment increases both the volume and velocity of stormwater runoff, and decreases its quality. Pollutants of concern include suspended solids, organic matter, heavy metals such as lead, copper and zinc, nutrients, bacteria and hydrocarbon derivatives. Urban runoff controls should be considered at each stage of urbanisation: during the planning of the transition from rural tourban land use, during the construction phase, and in existing urban areas . Different approaches need to be taken in each stage . In the last two years, EPA has emphasised the need for better controls on soil erosion from land disturbance activities, particularly on subdivisions, roads and major ~onstruction sites. The initial target has been the expanding eastern suburbs of Melbourne, where erosion has contributed to the long-standing turbidity problem in the Yarra River (EPA 1986b). Local government has been encouraged to specify adherence to good soil conservation practice in planning permits issued for new developments, in accordance with existing guidelines (Soil Conservation Authority, now Department of Conservation Forests and Lands 1979 and 1982, EPA 1987) . In the planning, design and construction of new urban areas, existing drainage systems should be assessed and integrated into the design to make best use of their capacity to attenuate flows and trap pollutants. Natural features such as floodways and wetlands should be supplemented by constructed flow retardation basins, retention basins, sediment traps and litter traps where appropriate. These engineering solutions must be backed up by a range of source controls to reduce the amount of pollutants generated in the catchment and the volume or velocity of runoff flow which transports the pollutants to waterways. Porous pavements, grassed swale drains, infiltration areas and appropriate litter control and street sweeping programmes are some of the possibilities . EPA has been involved in the preparation of guidelines for urban stormwater quality management through the Marine and Inland Waters Advisory Committee of the Australian Environment Council. Guidelines will refer to detailed manuals of good practice such as those drafted by the State Pollution Control Commission NSW (SPCC 1987), and those in use in the Australian Capital Territory (Department of Territories/ National Capital Development Commission 1986). EPA recognizes the importance of education in achieving success in all areas of diffuse source pollution control, particularly in urban areas. Its recycling unit is active in promoting effective litter control and recycling of waste materials. A video programme has been made to increase awareness by engineers and others of the need for erosion control in urban construction works.

â&#x20AC;˘ Runoff From Agricultural Land The policy requires improved control over agricultural land and water management, to reduce the runoff of salt , suspended solids,


nutrients and agricultural chemicals to watercourses. Establishment of vegetated streamside buffer zones and better management of irrigation water and the application of ferti lizers and pesticides are encouraged. Increasing salinity of land and water is a major problem being tackled by a coordinated Government strategy. Forestry operations should be better controlled to reduce sediment, nutrient and pesticide transport to streams. The recentlyprepared DCFL draft Code of Forest Practices is a sound basis for better forestry management, and compliance will help to overcome adverse effects of forestry on the environment and enable water quality objectives to be achieved.

• Mining Activities Victoria is experiencing a new gold-mining boom which has enormous potential for environmental impacts. Concerns include pump-out of saline groundwater from old mineshafts, disturbance of tailings dumps or stream sediments containing mercury from past gold extraction activities and erosion of soil from devegetated land. The policy places restrictions on activities which disturb stream sediments containing toxicants which may be mobilized into the water column. Some of these activities are controlled by EPA works approvals and licences, while others, such as eductor dredging, may need control by pollution abatement notice.

IMPLICATIONS FOR THE WATER AND WASTEWATER INDUSTRY The 'Waters of Victoria SEPP' will provide a consistent statewide approach to waste discharge control. It incorporates a number of principles which are generally applicable, such as minimum standards of treatment technology and discharge quality, but retains enough flexibility to permit the development of individual solutions to local issues. EPA's approach to wastewater management, as reflected in the policy, has a number of important implications for Victoria's water and wastewater industry.

Works Approval and Licensing The approval of works to treat sewage and industrial wastewaters and the licensing of waste discharges to the environment remain cornerstones of EPA's water quality control programme. The industries or waste types subject to works approval are listed in the Environment Protection (Scheduled Premises and Exemption) Regulations 1984. EPA's assessment of applications for approval of waste discharges to water is designed to ensure that the works provide the highest practicable level of environment protection. Questions which will be asked include: • Are waste discharges to waters in this vicinity prohibited by policy? • Are hazardous substances present in the discharge? • Is a sewer available to accept the waste? • Can the volume or strength of the waste generated be reduced? • Is the waste suitable for re-use by disposal to land? • Is the treatment technology proposed inappropriate? • Will the treated waste quality exceed emission limits? • Will the waste discharge cause water quality objectives to be exceeded outside an acceptable mixing zone? • Is the discharge or marine outfall design and location inappropriate? • Could future or increased waste discharges cause problems? • Should further studies be undertaken to assess environmental impact or waste treatability? If the answer to any of these questions is yes, the EPA may reject or seek modification of the proposal.

Nutrient Discharges to Inland Waters Most municipal sewage treatment plants in northern and western Victoria dispose of at least some, and often all, treated effluent to land rather than to water. EPA encourages this practice through policy, works approval and licence issue, and by participation in the Government's Task Force on Recycled Water. Where reuse of effluent on land is not practical, Schedule D of the policy provides that tertiary treatment may be required where

receiving waters offer less than 5: I dilution. to the discharge (based on average streamflow in the driest month of discharge) or where the discharge causes, or is likely to cause, eutrophication of receiving waters. In implementing this policy, EPA will concentrate initially on demonstrated problem locations. Action has already been initiated for a number of treatment plants. At Horsham, EPA recommended a 'Wimmera River SEPP' requiring that all Horsham's treated effluent be discharged to land in up to the 90th percentile wet year. Although cost analysis showed that tertiary treatment for phosphorus removal would be cheaper, the land disposal option had other benefits including removal of the balance of effluent pollutants loads from the river, conservation of water in a dry part of the State and a far higher level of acceptance by downstream communities. An extensive reuse scheme on Victorian Crops Research Institute land w·l be commissioned in 1988. The cost of the reuse scheme is to be shared by the City of Horsham and the Department of Agriculture and Rural Affairs. Conventional nutrient removal by chemical dosing is practiced at Lilydale, Sunbury and Ballarat North treatment plants. In view of disadvantages such as chemical sludge generation and effluent salinity levels, EPA encourages biological treatment of nitrogen and phosphorus removal and has supported the recent proposals for Wodonga, Bendigo and Ballarat South. In each of these cases the local water board has worked with consultants (Wodonga/ Gutteridge Haskins and Davey, Bendigo/ Sinclair Knight and Partners and Ballarat/ CSIRO) to adapt overseasderived technology to local conditions. Extensive pilot plant studies using some public funding have been carried out at Bendigo and Ballarat and the results should assist the wastewater industry greatly in future plant designs.

Disinfection of Sewage Effluents Wherever practical, the policy requires the use of techniques of wastewater disinfection which do not increase the toxicity of the effluent and which minimise environmental and human hazards from chemical manufacture, transport and use. In particular, EPA will question the use of chlorine as a wastewater disinfectant in view of its toxic residuals and handling problems. In Victoria lagoon detention is the most common method of disinfection. Lagoons also have disadvantages, including the land area required, algal productivity and erratic performance due to short-circuiting. Disinfection by ultraviolet irradiation is slowly gaining acceptance in Victoria and offers potential advantages over chlorination or lagoon detention. In remote inland locations, such as alpine areas, or discharges to ocean waters, no disinfection at all or seasonal disinfection are options worthy of exploration on a case-by-case basis .

Potable Water Treatment Plants Schedule D of the policy requires that wastes generated by potable water treatment plants be managed to avoid the discharge of untreated filter backwash, clarifier underflows or sludges to the environment. The approach taken in the policy is along lines foreshadowed in the I 984 EPA publication 'Control of Wastewater Discharges', which was distributed to interested parties. The emphasis is on solids separation from wastewaters, with recycling of supernatants through the plant where possible and drying and proper disposal of sludges to land. If a discharge of wastewater is necessary, a maximum suspended solids limit must not be exceeded.

FUTURE DIRECTIONS In a climate of government funding constraints, EPA is continually seeking to 'achieve more with less'. The taking on of new priority programmes such as industrial and hazardous waste control, recycling and diffuse source control has meant that EPA's operations must become more efficient. In controlling water pollution, the emphasis is on prevention rather than curing problems after they have arisen, and on responsive and effective client service. Works approvals, pollution abatement notices and EPA's complaint service have these objectives. In mid 1987 EPA restructured its operation on a regional basis. Operations teams now have responsibilities for air, water, waste WATER December, 1987 43

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Water Journal December 1987  

Water Journal December 1987