Water Journal February 1989

water

ISSN 031 0- 0367

Vol. 15, No. 6, February, 1989.

Official Journal AUSTRALIAN WATER AND WASTEWATER ASSOC IATION

CONTENTS My Point of View Rod Lehmann .. ... .. .. .. .. .. . .. .. ... .. ... ... .. . .. .. ... .... .. .... . .. ... ..

5

Technical Note: The Use of Wedge Wire Screens in Wastewater Treatment D. J. Bristow .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..

38

HAZWASTE Update................. .......................

Statement of National Water Research Priorities....... .... ... ... .... .... ........ ........ ..... ... .... ............. ...

Calendar .. ...... .. .. ........... .. ... ... ...,.. .. ............ ...... ... .........

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

40

Association News President's Report... ......... ...... .. .... ........ .. .. ..... ....... .. ... 路 It Seems to Me.... .. .... ... .. .. ..... ... .. ... .... ...... ....... .. .. ... ....

IAWPRC News..... .. ....... ....... ......... .. ... ..... ..... ... ... ... .....

Industry News .. .... ...... .. .. .. .............. ..... ................ .....

Water Quality for Recreation & Tourism.. .. .. ....

Biological Nutrient Removal Update A report by Bob Swinton.. ...... .. ......... ...... .... .. .. .. .. ...

6 7 11 12 13

42 44 45

15

Water Quality in Resort Islands - Management of Water Quality: Great Barrier Reef Marine Park S. J. Woodley .. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .

20

- Legislation affecting Water Management on Tourist Islands L. de W. Henry .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. .. .. .

24

- Total Water Management on Resort Islands: Design, Operation and Maintenance G. A. Nolan and I. R. Cameron............ .. ...... .... ... .....

OUR COVER Brilliant turquoises of the clear water of Wistari Re?f, near Heron Island in the Capricorn Group of the Great Barrier Reef. Even here the quality of the water is monitored lest some pollution threaten the reef corals and creatures.

28

- Manganese Removal: A Model of Cooperative Research D. R. Dixon , L. I. Sly, T. D. Waite, 8. Chiswell , G. E. Batley...... ........ .. ........ .. .. .. .................. .. .... ........

32

An Automated Colorimetric Method for the Estimation of Manganese in Raw Water P Aldridge, 8. Chiswell , M. K. Leigh, K. O'Halloran , M. Pascoe.. .... .... .. .. .. ...... ..... .... .. .........

FEDERAL DIRECTOR T. Smythe. G .H .& D. P.O Box 39 Railway Square.

Sydney NSW 2000 (02) 690 7070

EXECUTIVE DIRECTOR P. Hughes, P.O Box A232 , Sydney South 2000 (02) 269 6814 OFFICE MANAGER Ms M. Bates (02) 269 6157 Fax (02) 264 3668

FEDERAL SECRETARY G. Cawston, Box A232 P.O. Sydney Sth., 2000 (02) 522 1148

FEDERAL TREASURER J. D. Molloy.

Cl路 M.M.B.W. G .RO. Box 4343, M.elbourne 3001 (03) 615 5991

BRANCH SECRETARIES Canberra, A.CT. M. Sharpin, G.H . & 0., P.O. Box 780, Can berra 2601 (062) 498 522

New South Wales Mrs S. Tonkin路Hill, Sincl air Knight & Part.

1 Chandos St. , St. Leonards, 2065 (02) 436 7166

Photograph and colour separations by courtesy of the Queensland Department of Environment, Conservation and Tourism.

35

South Australia R. Townse nd , State Water Laboratories, E. & W.S. Private Mail Bag , Salisbury, 5108. (08) 259 0 244

Western Austral ia A. Gale, Binnie & Part PIL, P.O. Box 7050, Cloisters Square, Perth 6000 (09) 322 7700

EDITORIAL CORRESPONDENCE E. A. Swinton, 4 Pleasant View Gres. , Glen Waverley 3150 Ottice (03) 560 4752 Home (03) 560 9306 Fax Cl路 543 661 3 (Advise per phone)

ADVERTISING An n Sykes Appita 191 Royal Parade, Parkville 3052 (03) 347 2377

Tasmania Victoria J. Park, Water Training Centre, P.O. Box 409, Werribee, 3030. (03) 741 5844

A. B. Denne P.O. Box 78A, Hobart 7001 (002) 30 5562

Northern Territory Queensland D. Mackay, P.O. Box 412, West End 4102. (07) 844 3766

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

WATER February, 1989

I

WATER QUALITY FOR RECREATION AND TOURISM THE WORKSHOPS A Report by Mike Lever This conference, co-sponsored by IAWPRC and AWWA, was held in Brisbane in July 1988. Many of the papers presented in the technical sessions are in process of publication by the IAWPRC in ' 'Water Science and Technology" (Permagon Press).

In addition, five Workshop sessions were run, and a selection of material from these will be published in editions of Water.

In this edition, the related themes of management of coral reefs, and water quality on tourist islands are reported.

Coral Reef Management A plenary paper on management of the Great Barrier Reef Marine Park presented

by Simon Woodley is published in this edition. The workshop discussions were chaired by Mr Andrew Gormley, Queensland Department of Environment, Conservation and Tourism, and led by Assoc Prof Des Connell (Griffith University), Prof Paul Greenfield (University of Queensland), Dr Claudia Baldwin (Great Barrier Reef Marine Park Authority) and Mr Phillip Cosser (Queensland Department of Environment, Conservation and Tourism).

The major theme emerging from the presentations and the discussion was that the greatest threat to coral reef ecology was nutrient enrichment of the water column.

At present, insufficient information is available to fully understand either the extent and the intensity of nutrient enrichment, or the detailed mechanisms of ecological response to nutrient enrichment.

It is well understood that corals can thrive in waters with very low nutrient levels and that they degenerate in elevated nutrient environments. It was estimated that the tolerance level of corals to phosphate is 7.4 µg / 1 against an average background of 6.8 µg / 1, and the tolerance to inorganic nitrogen stands at 15.4 µg / 1 against an average background of 14 µg / 1. It is obvious that with a critical level only lOOJo above the background level, there is little room for manoeuvre and no room fo r ignorance.

The major sources of nutrient input were identified as: mainland freshwater runoff, continental island runoff, atmospheric fallout, regeneration from marine sediments, continental shelf upwelling and point source discharges such as sewage effluents. Of these, mainland freshwater runoff was regarded as the most significant on a regional scale. Point sources are capable of degrading coral close to a discharge, and a typical secondary-treated sewage plant effluent would require an initial dilution of 1:14 000 (yes, fourteen thousand) to avoid any localized coral degradation. However, on the regional level such point sources contribute a very small fraction of the nutrients which are carried into coastal waters

by rivers. Nutrient levels in rivers are largely a function of land-use practices, and so have a direct bearing on the health of the Great Barrier Reef. Special reference was made to the place of the tourist industry both as a beneficiary of the reef environment and a contributor to its degradation.

Management of Water Quality on Tourist Islands This workshop was chaired by I.eon Henry (Scott and Furphy) who also presented a paper on the complexities of the legislation covering tourist developments.

(Published in this edition) Geoff Nolan (Ullman and Nolan Pty Ltd) led the discussion on the practical aspects of water engineering on these island resorts. (also published in this edition) Peter Crawford (Qld Dept Harbours and Marine) discussed the management of water quality in marinas, which are mainly built on the mainland, though some are on the islands. In his paper he drew on the experience of many marina operators. Probably because of its visibility on the water surface, pollution by oil and fuel causes the most concern. Proper design of the facilities for refuelling both by hose and in portable tanks is essential to prevent the cumulation of frequent small spills. Cleanup equipment such as absorbent mats or booms is preferable to the use of dispersants.

Seepage and stormwater run-off from urban areas, car parks and shore-side facilities (particularly food outlets) are nearly always more significant than waste discharges from moored vessels. The provision of pump-out facilities in all new marinas will eventually lead to more boats being fitted with sullage tanks, but this problem is better addressed by the provision of such a high standard of on-shore facilities that patrons will prefer to use them, even to the extent of washing up after a meal on board.

Though not strictly a water quality problem, the control of dry refuse and litter is a continuing management task. It more frequently arises from take-away food outlets, or just blown or swept in from upstream, than from the moored vessels.

However, this does not seem to be the case with empty bottles and cans. The habit of " boaties" of discarding these into the very environment which they use for recreation demonstrates a flagrant disregard for the future. There may be considerable efforts to keep the surface of the water clean, but there is little concern for what may sink to the bottom.

The environmental impacts of tourism development, both land and water-based, was discussed by all speakers, and the forum provided the opportunity for those present to add to the sum total of experience (anecdotes ranged from the candid to the hilarious).

LEGIONNAIRES DISEASE IN SOUTH AUSTRALIA Generally from five to fifteen sporadic cases of Legionnaires Disease resulting from infection with 1.egionella pneumophila are recognized in SA each year. These cases represent a small percentage (1-20Jo) of all community-acquired pneumonias. One significant outbreak of 1.egionella pneumophila infection was recorded in 1986 with some 20 cases ascribed to a single source.

Over the last two years cases of Legionnaires Disease have been found to be caused by another species, L. longbeachae type 1.

These cases were also sporadic and distributed over the length of the metropolitan area. Recently a cluster of these cases was centred on the southern coastal suburbs.

No single common source would be defined for these cases and detailed casefinding has found some contemperaneous cases much further afield. The investigating team has noted a strong association with these cases and gardening, and microirrigation systems installed at a height above the ground. Such an association has been noted before in Sweden though in no case has an environmental source of L. longbeachae type 1 been found .

The possibility that micro-irrigation systems could be the source of infecting organisms is strong when considering that many such systems will hold some stagnant water over winter. The black polyethylene provides a means of heating that water and selecting with time a thermophilic flora.

Come the first hot day~ of spring, all that water will be flushed out as a fine spray. Inhalation of aerosols of 2-5µm diameter containing organisms are required to initiate infection.

-, There seems to be no reason that routine maintenance of such systems should not keep them free of hazard. In particular, associated filters should be clean, the systems could be made self-draining and pipe runs can be flushed clean by removing the end rings.

Investigation of the microbiology of these systems with the assistance of the • plastics industry is being planned.

A. S. Cameron Senior Specialist Communicable Disease Control Unit South Australian Health Commission THE INTERNATIONAL CONFERENCE ON ERGONOMICS, OCCUPATIONAL SAFETY AND HEALTH AND THE ENVIRONMENT Report by H. HANDLER The International Conference on Ergonomics, Occupational Safety and Health and the . Environment (ICE-O-SHE) was held in Beijing, China. This conference was organized by the Darling Downs Institute of Advanced Education, Toowoomba, Queensland (DDIAE) and the Chinese Society of Metals, Beijing, China. It covered a wide range of topics as implied in its title. The fact that the Conference attracted over 360 delegates from 31 different countries showed that the topics dealt with are indeed of universal concern in both developing and developed nations.

WATER February, 1989 13

Biological Nutrient Removal Update (AWRC Workshop, Ballarat, October 1988) (A REPORT BY BOB SWINTON) INTRODUCTION Arising from the increased interest in biological nutrient removal (BNR) a workshop was organized by Bill Raper (CSIRO) and Bruce Price (Ballarat Water Board), to follow the Victorian Branch Weekend Conference in October. Seventy people registered from Victoria and New South Wales, and one from Brisbane.

1\venty brief presentations provided an overview of the situation in Australia. Some of the presentations summarized work which has already been published, in this journal and others; some foreshadowed papers which will be presented in full at the Biennial Convention in March, 1989, or in other literature. In this report no references will be given other than the name and organization of the main author, to whom enquiries can be addressed directly. . The workshop, held in the very Victorian surroundings of the Sovereign Hill Goldmining Township, was opened by Bob Ford, Chief Engineer of the Ballarat Water Board . As has been reported, Ballarat's full-scale phosphorus removal plant was commissioned earlier in the year.

EUTROPHICATION The first session, chaired by David Mitchell (CSIRO, seconded to the Murray-Darling Freshwater Research Council) discussed eutrophication in Australia, and commenced with an overview by Ian Smalls (NSW Department of Water Resources).

Interest in eutrophication in Australia started in the early 70's.

Ian Small investigated the problem of algal blooms in Sydney's water supply storages, and Bill Williams investigated the weed growth in Lake Wendouree, Ballarat. By 1983 it was estimated that the cost to the nation was of the order of $10-50 million annually.

The overt occurrences of algal blooms and weed growth in lakes and rivers are not the only adverse effects of nutrient supply. Most Australian towns and cities are supplied with water through tubes of biological slimes supported on the inner surfaces of concrete, steel or plastic pipes. This ecosystem has its dangers also, both with regard to water quality and head loss.

Many Australian rivers have high concentrations of phosphorus.

The 90 percentile for the Lachlan and Macquarie is 300 microgram/L and that for the Darling is even higher, but algal growth is not usually stimulated in-stream, because of the high turbidity. Blooms occur when the turbidity is reduced, either in weir pools, off-stream storage, or periods of low flow. Although eutrophication of lakes and storages is now fairly well understood, the reaction of Australian river systems still requires much study.

Derek I.owe (Deputy Manager Water Branch, NSW State Pollution Control Commission) discussed the legislative approaches available in NSW. Even after some years of application of controls, many waterways in NSW are still under stress, long stretches being heavily populated by both micro and macrophytes. Although the SPCC tries to control the point sources, the diffuse inputs can predominate. Also, the current regulations are cased in qualitative language, but this is now changing to a greater emphasis on stream quality expressed in quantitative terms, and integrated catchment management is being established. For example, in-stream water quality targets for typical dry weather flow are defined (mg/ L) as TKN, 0.5: P, 0.05: NH,-N, 0.1: with the ratio N/ P at least 10 to 15 to discourage toxic species of algae. For trout streams, the ammonia levels are more stringent.

For control of point sources, either effluent use on land is encouraged, or the "Best Practicable Technology" for nutrient removal. 'fypical limits for point discharges are TKN < 15, P < 1, NH,-N < 2-5 mg/ L, but these can be adjusted to suit the receiving water. For example, the discharge limits from the Alpine resorts stipulate NH, < 0.5 mg/L. Control of diffuse sources, both urban and rural, can only be exercised in collaboration with other Government Authorities. In the urban area, SPCC stipulates stormwater and sediment control in land developments, and regulates nutrient inputs. On the rural scene, the long term aim is for a State-

wide catchment management policy, with rational controls designed to protect specific beneficial uses of the receiving waters.

MACROPHYTES Peter Breen, (previously with the CSIRO Division of Water Resources at Griffith, now with the Dandenong Valley Authority), described the pilot scale experiments with trern;hes in which macroifhytes were grown and harvested. These have not been very successful so far, with average removals of only 30% of N and 50% of P. Tracer studies using Br demonstrated that in a trench the main flow short-circuits along the base, below the major root zone, because of the lower hydraulic resistance. Experimental pot systems, filled with gravel, were tried at Griffith and it was found that they were consistently very successful, with removals of over 95% of influent N and P. In these pots the flow of wastewater was from the base of the pot up through the root zones of the plants. Mass balances were performed on the pots. Nitrogen was 25-40% nitrified at first but in the long term the plant took up most of the N. Phosphorus was equally distributed between the leaves, the roots and the rhizomes. There was little adsorption onto the surface of the gravel medium. Harvesting of the macrophytes is necessary to maintain the efficiency of the system, but removal of the roots is not necessary.

For populations of less than 5000, trench systems could cost of the order of 10% of the cost of other technology, but in order for them to work, the hydraulic designs must be such that the water is forced to flow through the active roots. Various techniques for ensuring this were discussed, but to date there,have been no trials.

The reed bed system, proposed by Kickuth, was described by Tom Davies of the Chisholm Institute. In this system no attempt is made to harvest the biomass, which is merely allowed to rot down on the surface. Oxygen is carried down inti) the aqueous phase through the hollow stems of the reeds. Nitrogen removal can only be by nitrification and denitrification, and results in Denmark showed variations in removal from 13 to 84%. Phosphorus removal was also very variable, the only mechanisms being conversion of the organically bound P to inorganic precipitates. However, some recent work has shown that formation and vapourization of PH, can be significant.

These large and unexplained variations have prompted a 3-year project by Chisholm at Frankston WTP, funded by Mornington Peninsula Water Board. Six beds 30m by 5m have been installed, and planted with Phragmites, alongside six unplanted beds. The experimental design covers a wide range of parameters, with regular monitoring of DO, pH, BOD, N and P species. If reed beds can be made to work consistently, design estimates are for an area of 2.5-3.0 m' per equivalent person.

ACTIVATED SLUDGE SYSTEMS Bill Raper, of the CSIRO Division of Chemicals and Polymers, Water and Wastewater Treatment Program, opened this session by listing the 15 varieties of activated sludge processes which have been tried throughout the world for combined nitrogen and phosphorus removal. He quoted definitive references for each of them, ranging from the first observations by Vacker, Connell and Wells in 1967, then Barnard's review in 1976, through to the present day.

For the typical water authority engineer faced with a demand for removal of nutrients, this is a bewildering array. Four consultants with experience in this field then explained how they would go about advising a client.

THE CONSULTANT'S PERSPECTIVE Harry Grynberg of Gutteridge, Haskins and Davey, has been involved in the installation at Penrith, which has been in operation WATER February, 1989

15

for three years, and is a conjunctive application of BNR with chemical precipitation, and the new plant at West Wodonga, which has yet to be commissioned.

For future proposals the following points would be discussed with the client.

1. In order of difficulty, waste treatment processes range from removal of BOD; nitrification; denitrification; then to BNR, which involves both anoxic and anaerobic stages. It would be stressed that the operation of BNR is a number of levels more complicated than mere removal of BOD, and operator competence must be appropriately increased.

2. The amount of knowledge already known would be listed, and it would be honestly stated that there is still a lot to be discovered.

3. The significance of "readily available" COD (RACOD), and the ratios TKN/COD, BODIN, BOD/Pin the raw sewage would then be explained, in relation to the type of process to be recommended. With a high RACOD ( > 60 mg/L) a simple flowsheet such as the 3-stage Bardenpho or Tel Aviv would suffice, and pilot plant studies would not be necessary. For medium RACOD (30 mg/L) the recommended flowsheet would be UCT or Modified UCT, and a pilot study may be advisable. For low RACOD (10-20 mg/L) it . would be necessary to modify the influent sewage by a prefermentation stage, and a pilot study would be advisable, particularly for prefermentation.

4. To cover possible alterations in influent characteristics, and any developments in fundamental knowledge of the process, a flexible plant should be designed.

Gordon Sewards, of Binnie and Partners described the development of the Ballarat South plant. A joint project involving CSIRO, Monash University and the Ballarat Water Board was instituted to determine whether biological phosphorus removal, followed by nitrification on the trickling filters, would be a feasible alternative to chemical precipitation.

The pilot plant results determined the basic plant design, but the unknowns were such that a large degree of flexibility was desirable. Binnie and Partners designed such a plant and utilized existing structures and some disused tanks as far as possible. Although this meant that the retention time would not be as high as was recommended by the pilot study, the savings justified the risk.

If nitrogen removal had been stipulated as well, it would have been a very different plant, so it is vital to be sure what effluent quality is really needed.

Peter Griffiths, of Sinclair Knight and Partners, was involved in the design team for the Bendigo plant. Investigations by the Water Board and Bendigo C.A.E were combined with South African experience, called on by SKP. The team scanned the systems available, and based on knowledge of the influent characteristics, recommended the Modified U.C.T. flowsheet .

Pilot plant testing specified a large number of tanks with flexible interconnections. This was transferred to the full-scale design as one large tank with many cheap transferable baffles.

Because of the sensitivity of the recycle stream to any excess oxygen, more accurate design factors than were available in the literature were required for the aerators. After a modelling study, multiple 2-speed surface aerators were installed in order to have · the flexibility required. Flexibility was also built into the sludge pumping systems.

Ian Law, of Camp Scott Furphy, projected himself into the persona of a Water Authority Member, and he considered that the decisions would not be really so difficult. All the 15 flowsheets are combinations of aeration, anoxic and anaerobic zones, or equivalent periods. The questions to be posed are: • Influent characteristics, hydraulic and chemical?

• Temperature variations?

• N only, P only, or both?

• Sludge disposal options?

• Site area?

• New or retrofit?

• Background of the designer?

• What skills are available in the Authority?

• Patent situation ... any royalties, if so how much?

For N-removal only, the biological system is the only way to go.

For P-removal only, the high-rate system installed at Ballarat is fine.

But for N and P it is more complicated. There is much to be said for conjunctive chemical precipitation of P both as back-up in case of breakdown, and to cope with temperature effects.

16

WATER February, 1989

Two final points: No consultant can yet.,place a full-scale design on the desk as a turn-key project; advice from research organizations for each particular application is still needed.

Secondly, operator training conducted by the design consultant is vital.

AUSTRALIAN RESULTS -

FULL SCALE

This session, chaired by Ian Law, summarized the results obtained from a number of widely differing plants which have been installed over the last three years.

Penrith, NSW Robert Mann of the State Pollution Control Commission summarized the results of the first BNR plant in Australia. The S.P.C.C., in conjunction with the Penrith City Council, and GHD as consultants, first characterized the inflowing sewage.

The plant installed was a carousel system, followed by maturation ponds, and was modified by installing various stages of anoxic conditions in an extra channel, to assess its ability to perform BNR. Three trials were operated, the first with no modification of the inflow. The second trial recirculated the primary sludge, which was rich in RACOD, at 10 am and 3 pm each day. In the third trial, intermittent mixing of the anaerobic channel was tried to provide more VFA. However, the results were not promising.

The influent from 1985 to October 1986 had total P averaging 8.3 mg/L, and FRP of 5.3 mg/L The effluent averaged 4.9 mg/L, but occasionally was as low as 2 mg/ L. In the three trials the Premovals were 400Jo, 370Jo and 520Jo respectively, (but in the latter case the influent P had also risen). TKN was reduced to about 15 mg/L, and NH,-N to less than 6 mg/L. BOD and COD were reduced by 980Jo and 910Jo during these trials.

There were some operational problems which could have masked the results. For example, during the period the inflow increased from the design figure of 6 ML/d to 10 ML/d, and there were many mechanical and instrumental breakdowns. However, the probable cause of the poor removal of P was the low level of RACOD in the raw sewage. (This was discussed later by Mann and also by Bliss.)

Ballarat South Bruce Price of the Ballarat Wat,er Board described the Ballarat plant, which had been commissioned in April, 1988 . The residential population connected is approximately 55 000 and the industrial loading equivalent to 20 000. The Victorian EPA imposed a limit of 10 mg/L NH,-N, and foreshadowed a likely limit for P of 2 mg/L. The cost of chemical treatment was estimated to be $300 000 per annum for chemicals alone.

The Board determined in 1982 to investigate the possibilities of BNR and discussion took place with CSIRO (Bill Raper). The emphasis was changed to a high rate process because this would enable existing facilities to be utilized . The existing trickling filters could be used to nitrify the ammonia, so that BNR would concentrate on P removal. Pilot plant investigations were commenced in 1983, in collaboration with CSIRO, and, as described by Gordon Sewards, a flexible full-scale plant was designed, based to a large extent on modification of existing equipment. The total augmentation cost was $4.1 million.

The anaerobic tanks were commissioned in April 1988, and within three days the P concentration in the effluent leaving the aeration tanks was less than 1 mg/L. In the first two months there were the usual teething troubles with equipment, particularly with the control of the air blowers, but whenever DO in the aeration tanks was maintained above 1 mg/L the P concentration in the effluent from those tanks fell to less than 1 mg/L. At any stage, further aeration of samples in the laboratory reduced P nearly to zero.

However, after these troubles were overcome, it became clear that in the winter temperatures (around 15 °C) the available aeration was insufficient for adequate P uptake, particularly with wet weather flows.

Investigations now take samples from the plant and measure the rates of uptake of P in the laboratory under conditions of adequate aeration. The time to reduce P to zero varies from around two hours to well over four hours, depending on the MLSS concentration. A further observation is that although the average flowrates during a weekend are unchanged, and P removal is good, there is a marked change on Monday afternoon, when the time for zero

uptake increases from the "norm" of 2.5-3 hours, to more than six hours. Whether this is a function of some sudden input from an industrial source or a delayed weekend effect is not yet known-.

The overall performance of the plant has improved steadily in the six months of operation. Currently, P is reduced from an average of 10 mg/L to about 3 mg/L and the trend is still downwards. Total N is about 20 mg/L, and NH,-N is about 5 mg/L. With the onset of winter, it may be necessary to consider an additional aeration tank and/ or a flow-balancing storage. It is noteworthy that the anaerobic digester sludge is dewatered on a belt press, and the filtrate can be returned to the head of the plant without lime treatment to precipitate its P content. It would seem that the P released from the sludge is being precipitated within the digesters as "struvite" (magnesium ammonium phosphate).

Bathurst Haman Awad and Fred Cozma, of the NSW Public Works Department discussed their observation that the "fill and draw" sys-

tem of the Bathurst Box will, under certain circumstances, remove phosphorus. Investigations have shown that the following factors contribute: .. Cessation of lagoon supernatant return to the aeration tank.

• High acetate levels in the influent from the Kelso rising main, which has 12 hours detention time, after about 24 hours in the preceding gravity main.

• The significance of redox potential, as well as DO levels, fo the aeration phase has been observed.

Although the process seems sufficiently robust to survive short term operational upsets, it takes a long time to re-establish after a severe rain event. Investigations are continuing.

PILOT PLANT STUDIES Castle Hill, NSW Peter Bliss of the University of New South Wales reported on their studies on the pilot plant at Castle Hill, which deals with the weak domestic sewage which is typical of most of the Sydney Water Board's inland treatment plants.

The first study was published at the AWWA Convention, 1987, and that has been followed by attempts to increase the RACOD in the influent. It is now realized that this is not the full story. 200 L drums were interconnected in varying configurations followed by a deep final clarifier with return sludge pump. In the event, no configuration achieved more than a reduction of P from 8-12 mg/L to ca. 4-8 mg/ L with peaks. An attempt to feed "soured" primary sludge intermittently by means of a daily bucket-full was just as unsuccessful, but when this feeding system was replaced by a continuous pump, the system did work, and the effluent P fell to less than 1 mg/L. It was established that to treat the Castle Hill sewage, a RACOD of at least 30 mg/L was necessary, and the return sludge must be given a separate anoxic treatment to remove nitrate.

Studies then concentrated on methods of producing RACOD. Analysis of VFA rather than RACOD was used. It was found that VFAs originated from the solids fraction . A pilot-scale activated primary sedimentation tank was not successful, but batch fermentations were encouraging. The most that could be achieved from this weak sewage was 30-40 mg/L of acetate.

Close attention must therefore be given to maximizing prefermentation.

Ballarat and Lower Plenty Pilot Plants, Victoria Bill Raper (CSIRO) reported on the latest results. Those for Ballarat pilot plant were published in the 1987 Convention, and showed that P could be reduced to 0.5 mg/L in summer, with 1:1 ratio of aerobic to anoxic retention-time. In that investigation, diurnal concentration was followed, but the flow to the pilot plant was kept constant. In later investigations, the flow patterns were modelled as well, and the results were much the same. It was noted that TKN was reduced by as much as 80% in summer conditions, but this was not achieved in winter. (Similar results were noted for a pilot plant in USA.) It seemed that nitrification and denitrification were occurring simultaneously in the aerobic tanks. The only possible explanation is that there must be micro-zones in the tanks which are anoxic, possibly in the centre of floe clusters ..

The pilot plant now operating at Lower -'lenty, funded by the Urban Water Authorities, has been designed to be very flexible so that any of the presently known flow-schemes can be simulated.

The influent sewage is typically wholly domestic, and an activated primary tank has been found to be essential.

The investigation was started with a 5-stage Bardenpho system, with constant feed rate but diurnal concentration profile. After resolving the teething troubles (mainly due to the difficulties in pumping sludge at pilot plant rates) the effluent P soon dropped to 1 mg/L. lwo month's steady operation gave the following results: Composite influent: TKN 52 mg/L, TP 9 mg/L. Composite effluent: OX-N, 2 mg/L: NH,-N, 0.4 mg/ L: PO4-P, 0.3 mg/L. This proves that the microbiology of the system, in &trictly controlled conditions, can do a superb job, bu these results cannot necessarily be repeated on a full-scale plant. However, as noted by Bruce Price, the full-scale plant at Ballarat can achieve 0.2 mg/L, PO4-P, given sufficient aeration.

The next phase of the Lower Plenty investigation was to simulate the un-patented 3-stage Bardenpho system. Results were similar. However, attention needs to be concentrated on a rational design basis for the prefermenter. Sludge age is also a vital factor to be investigated further.

Bendigo Pilot Plant, Victoria Ken Lindrea of Bendigo C.A.E. described the work conducted in their laboratories in conjunction with the Bendigo Water Board and SKP, with advice from Marais and Ekama of South Africa.

The system investigated was the modified UCT, conducted in a series of 5L plastic vessels.

The system has been under investigation for three years and has given good results. The profiles of OX-N, P, and RACOD throughout the reactors have been established. The elimination of nitrate from the anaerobic zone is essential, particularly where the TKN/COD ratio in the influent sewage will not permit complete denitrification. An experiment was conducted where an excess of acetate was added, but followed by 5 mg/L of NO3-N. There was immediate release of P, up to 50 mg/L. This emphasizes the advantage of the Modified UCT system, where the return sludge is passed through an intermediate anoxic zone, before being pumped back to the head of the anaerobic cf:iain, in order to denitrify it completely.

Long term studies of the Modified UCT system have indicated that it has other advantages apart from its ability to maintain a nitrate-free anaerobic zone. These are: maximization of the utilization of RACOD, the provision of a reservoir of polyhydroxybutyrate and stabilization, control and flexibility of operation.

INFLUENT CHARACTERIZATION This session, chaired by Paul Dougas, of Sinclair, Knight and Partners stressed that there was a need to know influent characteristics not just in terms of the old parameters, but in terms of those which are important for the development of viable populations of acinetobacter.

Sydney Robert Mann, of the S.P.C.C.,investigated the influent to the Penrith plant. Methods were developed to assess the readily biodegradable material, (variously termed RBCOD or RACOD) and the volatile fatty acids (VFAs). The levels of these in the Penrith sewage and from four other treatment plants in west Sydney were determined.

The aerobic batch method, used for analysis of RACOD, must be performed on-site, otherwise the sample must be cooled to 4 °C, and transported for no more than 1 to 2 hours before it is reacclimatized and analyzed. VFAs were determined by HPLC, on a silica column, which partitioned them into Cl-C4 fractions; 200 ml samples were dosed with chloroform as a bactericide, held at 4 °C, and colour removed by powdered activated carbon. Such samples were found to be stable for at least 2 days. After 8 days storage, the lower molecular weight acids tended to disappear.

The results showed that the RACOD and VFA levels were much lower than those reported from overseas. VFAs ranged from 30-60 mg/L, compared with typical South African levels of 50-100 mg/L. WATER February, 1989

17

The ratio of RACOD to total COD ranged from 6 to 18%, compared to South African values of 10 to 30%. The ratio of total phosphorus to COD was about 0.08, which is also lower than that reported for overseas plants.

The reasons for these differences may be ascribed to different patterns of water usage, types of waste, retention time in sewers, and possibly the effects, in South Africa, of intestinal parasites.

The conclusion, as previously outlined by Bliss, is that modification of the influent by pre-fermentation is necessary before the BNR process will work on weak domestic sewage. Another possibility is the addition to the domestic sewage of a readily degradable effluent from a suitable industry, such as a brewery, or abattoir.

Melbourne and Ballarat The investigations into characteristics of the influents to the CSIRO pilot plants were summarized by Norman Pilkington, of the CSIRO Division of Chemicals and Polymers. Although VFA analyses can be useful, his philosophy was that no decision is better than the data on which it is based.

It starts at the level of sample collection and sample preserva. tion. For example, some analyses of a series of spot samples did not correlate with the corresponding composite samples. The latter had been collected over 24 hours but stored in unsatisfactory conditions. Whereas the average of the spots had VFA levels of 26 mg/L, the composite showed only 2 mg/L. The effects of storage were due to volatilization, adsorption onto particulates and microbial reactions, which can both increase or decrease the levels.

Investigations into various methods of preservation showed that though HgCl, is suitable for up to 10 days, immediate freezing was the most reliable. The technique adopted by CSIRO was to add sulphuric acid to the sample bottle, chill until needed, then mix in the sample and freeze until just before analysis.

For VFA analyses, two types of column were tried, the packed column and wide-bore capillary, and full details of procedures and detection limits were given. A practical point was that with appropriate attention to maintenance and cleaning, the life for a packed column has been extended to more than 850 samples, while in excess of 2500 samples have been analyzed on the wide-bore capillary. This is contrast to previous costly recommendations that the columns be discarded after 30 to 40 samples.

The results of VFA analysis on Lower Plenty influents (a simple domestic catchment) showed wide diurnal variation with a single peak of 50 mg/L at around 8 pm, falling to zero at 5 am.

At Ballarat, daily variations on 24 hr composites ranged from 10 to 50 mg/ L.

Bendigo Ken Lindrea (Bendigo CAE) spoke on the investigations which have been conducted since 1980 by the Bendigo Water Board, first stimulated by the generally poor operation of their plant for normal BOD ~emoval. This showed very clearly the need for Trade Waste Control, which resulted in stabilization of the influent BOD, but also demonstrated that augmentation was necessary. Twelve months of very detailed monitoring followed, and it was possible to construct a mathematical model with reasonable accuracy for 25 day averages, so that trends can now be detected.

With the prospect of construction of a new plant incorporating phosphorus removal, analysis of daily samples for RACOD by means of the aerobic batch method was instituted, and data from over 900 days is now available. There is tremendous scatter, ranging from practically zero to over 150 mg/ L. The low values of RACOD associated with storm flushes can last many days after the event, possibly due to removal of bacterial slimes from the sewers, which play a role in the genesis of RACOD. The diurnal variation in RACOD ranges from 20 to 80 mg/L, but with multiple peaks, unlike that for Lower Plenty. It was noted that the ''Tuesday Jag'' described in overseas literature did not occur.

The investigation has extended to analyses of unbiodegradable COD, both soluble and particulate, and to the degree of inhibition of nitrifying organisms by materials in the influent.

BIOWGICAL MECHANISMS This session was chaired by Ron Bayly of Monash University, which collaborates with the CSIRO group. He reported that at the 18

WATER February, 1989

1988 conference in Rome, there were three groups of microbiologists, each with different ideas on the mechanisms for BNR. In his opinion, all of them may be correct, but for their own particular environment.

John May, also of Monash, described the collaborative work on the identification of the Acinetobacter species which are the workhorses for removal of phosphorus. When the Lower Plenty pilot plant first started, and was not operating effectively, the predominant ~acteria were filamentous. When the plant was operating, the bactena were in clusters, and contained deeply staining concentrations of polyphosphate. Recent work has divided the Acinetobacters into 12 genospecies, and the aim was to determine which was the dominant. Micro-manipulation on the microscope slide dissected out individuals, and it was found that the dominant species was Acinetobacter (12/21).

A number of the clusters were found to e dead, although they still contained polyphosphate. The capacity of the various strains to take up either acid-soluble polyphosphate or longer-chain insoluble polyphosphates was also investigated. It may be possible to identify the particular plasmid which is associated with this function.

Ann Beacham of the Bendigo C.A.E. then described the work which has gone on alongside the pilot plant investigations. S.E.M. photographs clearly show individual cells and clusters of the acinetobacter, whilst the visible light microscope can differentiate between loose and tight clusters. The project is to compare the number of genospecies in Bendigo with those being identified in the Lower Plenty plant, to establish variations during the year; and possible correlations between plant performance and the clustering behaviour of this bacterium .

Of the 12 genospecies known, nearly all have been found at Bendigo, whereas there have been fewer found at Lower Plenty. There was also a distinct difference between the various zones of the Bendigo plant; in the anoxic zones only four out of the twelve were found.

The main question is whether clustering is a function of the type of polyphosphate uptake. It was noted that pure cultures do not release their polyphosphate in the anaerobic zone, whereas mixed cultures do so. The speed.with which the species change from free bacteria to clusters is also to be assessed, in order to account for the rapid changes which have been noted in rates of uptake ob-1 served in Ballarat.

CHAIRMAN'S SUMMARY In his summary of the trends emerging from the workshop, Bill Raper drew the following conclusions: The most significant common factor emerging was the need to characterize the influent thoroughly before choosing a process flow -scheme. The methods used should include determination of either acetate or RACOD. If either if these is low, great caution must be exercised.

The sensitivity of the receiving water to each of the individual nutrients should be determined before any decision is made as to what plant is to be installed. The example of Lower Molonglo was cited, where the removal of nitrogen has now been demonstrated to be unnecessary, so that the expensive part of the process is no longer used. In Ballarat, the tolerance of the receiving creek to nitrate allowed a smaller, simpler process to be installed.

With respect to licensing of discharges, the use of limits of mass rather than concentrations may be of more relevance, and may be easier to achieve.

Macrophyte systems have shown excellent performance in smallscale trials, but pilot scale results have been poor. This is similar to the situation with activated sludge processes some years ago. It is encouraging that work is proceeding with explaining and overcoming these scale-up problems.

Authorities should strive to maintain close liaison between their technical staff and the consultants, in order to keep up with the advances in technology. â&#x20AC;˘

FUTURE BNR CONFERENCES Further opportunities for discussions were foresha dowed. Firstly, there will be a half-day Workshop organized at the AWWA Convention in March. Secondly, the interest is so great that a Specialist Conference with some international input is justified,

WATER QUALITY IN .RESORT ISLANDS The papers relating to the theme of this issue were presented at the workshop sessions of the IAWPRC-AWWA Conference on Water Quality for Recreation and Tourism, in Brisbane, July 1988.

The technical session papers are being published by IAWPRC in "Water Science and Technology" (Permagon Press).

Editor

MANAGEMENT OF WATER QUALITY: GREAT BARRIER REEF MARINE PARK S. J. Woodley ABSTRACT The Great Barrier Reef is the largest coral reef system in the world. It is recognized and appreciated worldwide as a unique environment and has been inscribed on the World Heritage List. The Reef is economically important to Queensland and Australia, supporting substantial tourism and fishing industries. Management of the Great Barrier Reef to ensure conservation of its natural qualities in perpetuity is being achieved through the Great Barrier Reef Marine Park.

Maintenance of water quality to protect the reef and the industries which depend on it is becoming an increasingly important management issue requiring better knowledge and possibly new standards of treatment and discharge. A summary is given on the main factors affecting water quality in the Great Barrier Reef Marine Park and of the steps being taken to manage their impact.

INTRODUCTION The Great Barrier Reef is the largest system of corals and associated life forms anywhere in the world, covering an area of more than 300 000 sq km. It stretches for almost 2 000 km along the northeastern coast of Australia in a complex maze of about 2 900 individuals reefs, ranging in size from less than 1 ha to 100 sq km.

In the area north of Cairns the Reef is narrow and its eastern edge is marked by a series of narrow 'ribbon' reefs, but in the southern and far northern areas it broadens out and presents a vast wilderness of 'patch' reefs separated by open water or narrow winding channels.

The Reef is diverse not only in the form and size of its individual reefs and islands, but in its inhabitants. There are far more than 1 500 species of fish and about 350 species of hard coral on the Reef. The islands are inhabited or visited by more than 240 species of birds. Whales, dolphins, turtles and dugong occur in the area in large numbers. · The recognition and appreciation held by people both nationally and world-wide for this unique environment, led to it being inscribed on the World Heritage List in October 1981.

The diversity and richness of the Reef has attracted a variety of uses. Commercial fishing and tourism, recreational pursuits including fishing, diving and camping, traditional fishing, scientific research and shipping all occur within the Great Barrier Reef Region.

The total economic value (excluding multipliers) in terms of gross output of the Great Barrier Reef Region and its islands amounts to about $250 million per annum. The economic value of some of the activities in the region, particularly tourism, is increasing rapidly, currently at about 10% per annum, though some recent estimates are much higher. Conservation of the natural resources of the Great Barrier Reef is critical for all commercial and recreational activities, particularly tourism, recreational fishing and commercial fishing. In 1984/85 expenditure by tourists at island resorts was $84 million. Expenditure in the same year on recreational fishing was $68 million and the commercial fishing industry output was $48 million. These figures of course are now much higher.

Potential impacts of pollutants on marine ecosystems in general was one of the factors which led to a world-wide awareness in the 20

WATER February, 1989

Simon Woodley, Assistant Executive Officer, Park Management with the Great Barrier Reef Marine Park Authority, Townsville, Queensland, graduated from ANU with a BA in Geography and Politics, and is currently studying for an MSc at James Cook University in Tropical &ology.

He has worked as a senior officer with GBRMPA since 1977, responsible for park management and was previously with the Commonwealth Dept of Finance, Canberra.

Simon Woodley

1970s of the need for more effective management of marine ecosystems. However, water quality issues on the Great Barrier Reef did not appear to be important at that time.

In the early days of commercial use of the Reef, pollution of reef waters, other than by events such as oil spills, was not perceived as a threat. However, in more recent years, the effects of chronic pollution on coral reefs has1 become more widely known and the need for preventative action more pressing. Public concern about apparent pollution effects on the Great Barrier Reef has grown with increased tourism and its associated infrastructure.

Maintenance of water quality is therefore an important part of conservation of the Great Barrier Reef.

THE GREAT BARRIER REEF MARINE PARK AUTHORITY Serious conflict on and about the Reef and its management first arose in the 1960s when the people of Australia became aware of, and objected to, proposals to drill for oil and to mine limestone on the Reef. The ensuing controversy revealed that the Reef was treasured by many Australians for its uniqueness, biological diversity, beauty and grandeur.

In response, the Federal Parliament pased the Great Barrier Reef Marine Park Act 1975, thereby signifying to the people of Australia the importance of the region as an ecological and economic resource that must be used wisely. This multi-use concept provides for the continuation of all 'reasonable' uses of the Reef while ensuring that those uses do not cause irreversible damage to its natural resources and do not conflict with each other. The Act provides for the establishment of the Great Barrier Reef Marine Park and the Great Barrier Reef Marine Park Authority as the principal agency responsible for management of the Park.

FUNCTIONS OF THE AUTHORITY The main functions of the Authority, in summary are: • to make recommendations to the Minister in relation to the care and development of the Marine Park, including areas that should be declared as parts of the Marine Park and the regulations that should be made under the Act; • to carry out and arrange for other persons or institutions to carry out research and investigations relevant to the Marine Park; • to prepare zoning plans for the Marine Park;

• to provide and arrange for the provision of educational, advisory and informational services relating to the Marine Park; • to furnish advice and information to the Minister on matters. relating to the Park, including agreements and financial arrangements between the Commonwealth and Queensland.

The Authority believes that any use of the Reef or associated areas should not threaten the Reef's essential ecological characteristics and processes. This belief has led the Authority to adopt the following goal: "To provide for the protection, wise use, understanding and enjoyment of the Great Barrier Reef in perpetuity through the care and development of the Great Barrier Reef Marine Park".

The Great Barrier Reef Marine Park Act 1975 provides for, inter alia, the regulation of acts (whether in the Marine Park or elsewhere) that may pollute water in a manner harmful to animals or plants in the Marine Park.

Permission is required from the Authority for discharging or depositing household, industrial or commercial wastes into the Marine Park, except for discharge of human waste from a vessel or aircraft which has no appropriate storage tank, for fish offal or for other biodegradable wastes which are discharged more than 500 metres seaward of the reef edge.

ZONING PLANS Zoning is the broad spatial partitioning of a Park Section to provide for multiple use at a level which is consistent with the maintenance of the ecosystem and which will be accepted as reasonable by society. Pre-existing use patterns often reflect many of the factors which need to be taken into account in zoning. Zoning plans therefore provide, as far as possible, for existing use patterns as well as attempting to ensure future sustainable use.

Zoning also provides the basis for separating conflicting activities. Areas are provided for particular uses and some small areas are protected from use. Levels of protection within the Park vary from almost complete absence of restriction on reasonable activity as in General Use W zones, to zones in which few human activities are permitted, ie Scientific Research or Preservation Zones.

The only activities which are specifically prohibited through6ut the Park are oil exploration, mining, littering, spearfishing with scuba and commercial spearfishing, and the taking of large specimens of certain species of fish. There are exemptions for education or scientific research.

The Authority cooperates with Queensland Government agencies in the development of zoning strategies and plans. In fact, there are complementary zoning plans prepared under the Great Barrier Reef Marine Park Act and the Queensland Marine Parks Act. A Public Participation Program is an important part of the development of the zoning plan for each section of the Marine Park.

MANAGEMENT The legal and strategic framework for management is provided primarily by zoning plans. Day-to-day management is carried out by officers of the Queensland Government, primarily from Queensland National Parks and Wildlife Service, in accordance with an agreement between the Commonwealth and Queensland Governments and the Authority.

In broad terms, this agreement provides for management of the islands, reefs and waters to be combined and responsibilities and costs shared between the Authority and Queensland agencies.

In agreeing to share responsibility for management of the islands, reefs and waters of the Great Barrier Reef Region, both Governments have promoted the concept of complementary management, ie agencies with responsibilities in the Great Barrier Reef Region should act in a complementary fashion in order to achieve common goals by joint action and also to avoid jurisdictional disputes, and to reduce scope for conflict and public confusion.

In the area of water quality, the Authority works closely with the Queensland Water Quality Council to apply agreed conditions to waste discharges.

In addition, the Authority relies on other legislation to complement the provisions of the Great Barrier Reef Marine Park Act. This approach attempts to reduce unnecessary duplication of statutes and provides support beyond the scope of the Great Barrier Reef Marine Park Act. For example, the Commonwealth Environment Protection (Sea Dumping) Act regulates the dumping of wastes beyond the territorial sea. When Annex IV of the. International

Convention for the Prevention of Pollution £!-om Ships is enacted by the Commonwealth shortly, it should prevent the discharge of wastes in the Great Barrier Reef Region by ships of greater than 200 tonnes or which are certified to carry more than 10 persons.

This will be a significant support to the protection of the Great Barrier Reef.

ENVIRONMENTAL IMPACT ASSESSMENT Where permits are required for major developments, the Authority undertakes a process of environmental impact assessment, the complexity of which depends on the significance of potential impacts both on the physical and social environment. Size of operation, location, complexity, purpose and perceived public interest are all factort which influence the choice of the environmental impact assessment process.

This process can range from in-house ass(;-Ssment by Authority staff in consultation with relevant experts but without public comment through to the preparation by the proponent of a substantial environment impact assessment report and public review through the Commonwealth Environment Protection (Impact of Proposals) Act. The latter process, depending on the extent of specific studies required to complete the report can take between six and twelve months.

Water quality matters of specific concern which must be addressed in such a process include potential effects on public health, social amenity and physical or biological effects, from: • discharges of sewage or hypersaline water; • fuel transfer handling; • suspended sediment loads from dredging or reclamation; • chemicals used in water treatment systems; and • anti-fouling paints.

In the experience of the Authority, providing the project generally fits within the zoning plan objectives, the environmental impact assessment process usually does not result in the prohibition of a project which initially appeared to have the potential for significant impacts on water quality. The usual result should be, firstly, to force environmentally-sound design to minimize the risks of environmental degradation and reduce actual effects to acceptable levels. Such design should include both initial works and subsequent operations. Secondly, stringent conditions for control of the operations of the activity should be set. Finally, monitoring of the operation for effects, including any w~ich were unforeseen, is now virtually mandatory and increasingly is paid for by the user. The emphasis as far as possible is on prevention of deleterious effects rather than rehabilitation after degradation.

To assess the reasonableness of use of the Marine Park, an appreciation of the physical and biological effects on the ecosystem are needed. It is rare, except in obviously destructive activities, that science can provide an unequivocal assessment that a particular use is ipso facto unreasonable. The reasonableness of a use, or level of use, at a site is a function of its impact on resources and in creasingly importantly, its interaction with other actual and potential uses at that site.

The Authority not only has to ensure that the physical environmental effects of discharges are kept within acceptable limits, but also has to satisfy public perceptions of apparent impacts on water quality. Discharges of sewage or oil into the Marine Park are certain to arouse public concern because of their high visibility in the public mind although the environmental effects may be negligible in most cases. However, " invisible" pollution through increased nutrient loadings which may be potentially more serious in their effects on corals do not arouse the same public concern .

WATER QUALITY ISSUES IN THE GREAT BARRIER REEF MARINE PARK Many of the main water quality issues which affect or might affect the Great Barrier Reef Marine Park are interconnected, but for the sake of discussion, can be separated into: sewage discharge; nutrients; toxic contaminants; oil; litter and marine debris; sedimentation; and antifouling .

Sewage:

Sewage discharge into the Marine Park can be from ships, other vessels, floating structures, island-based tourist resorts and from the mainland. There are 18 resort islands in the Great Barrier Reef Marine Park catering for an expanding market. Visitor nights increased by 17.5% between 1983/ 84 and 1984/ 85 and a doubling WATER February, 1989

21

of rooms is projected with the next few years. Many resorts have secondary treatment plants for processing sewage and others are in the process of upgrading. One floating hotel is in operation at John Brewer Reef with on-board treatment facilities to secondary standard. The sludge is incinerated on board and the effluent barged to deep water and dumped. A second floating hotel at Fitzroy Reef is proposed. No treatment on board is proposed. Instead, wastes will be transported to the mainland and deposited in land-based treatment systems. .

To date, the Authority has adopted the standards applied by the Queensland Water Quality Council for waste water discharged to Queensland water, ie the '20/30' standard. In general, existing microbiological standards seem to be adequate for the Marine Park environment.

Discharges from ships are permitted providing they are more than 500 metres from a reef edge. However, the expected enactment of Annex IV of the MARPOL Convention should reduce the discharge of raw sewage into Reef waters from this source. Discharges from other vessels, eg charter boats, are also permitted. The Authority encourages the fitting of holding tanks and in some cases may require such tanks as a condition of permit.

Discharges from mainland sources into coastal waters adjacent ¡to the Marine Park or into the Marine Park itself can be by direct discharge of largely untreated sewage or indirect discharges from streamflow and runoff. Pollution of inshore waters and reefs may be more important than point source discharges from islands but is much more difficult to measure.

Nutrients: A recent workshop conducted by the Authority has highlighted a general concern that inshore waters of the Great Barrier Reef have high nutrient levels and in localized areas may be reaching an undesirable threshold; in particular, waters near Cairns, the Townsville-Magnetic Island area and the Whitsunday Islands. Nutrient sources are from agricultural fertilizers, from sewage and from natural terrestrial sources.

Coral communities are quite tolerant of elevated nutrients in the short term; however, in the long term, extreme modification and degradation of the communities occurs and corals are considerably inhibited.

Possible standards based on coral growth rate limits or on limits to nutrient levels are being investigated. Monitoring of nutrient levels in areas of concern is planned and some preliminary studies carried out.

Toxic Contaminants: Toxic contaminants such as heavy metals (PCBs) and other organochlorines and hydrocarbons do not seem, at the moment, to hold serious threats to the Great Barrier Reef apart from the potential danger of an acute event such as a shipwreck.

A workshop on contaminants in waters of the Great Barrier Reef held by the Authority in 1984 concluded that measured levels of each contaminant group do not pose an immediate threat to human health, individual organisms or the Great Barrier Reef system as a whole.

Littering:

Littering is prohibited by regulation but still occurs, particularly by charter boats and fishermen. The extent of littering is difficult to quantify but appears to be more of a nuisance value and an aesthetic problem affecting people's amenity than a serious threat to water quality. However, there is the potential for problems on the Great Barrier Reef if overseas trends towards increasing volumes of garbage per capita are any indication. Education of potential offenders is the main control mechanism although on-the-spot fines and prosecutions are being pressed where possible.

Sedimentation:

Reduced water quality at particular sites can occur through the effects of suspended sediments. Increased sedimentation arising from onshore land clearing and road building, dredging for harb ur maintenance and subsequent dumping of spoil and dredging for reclamation and construction of marinas are recent examples of this potential problem.

However, sorting out the effects due to development works from the effects due to natural events can be difficult. Monitoring of the effects on coastal fringing reefs of sediment run-off from road construction at Cape Tribulation has been complicated by a tropical cyclone in April 1986 which reduced coral cover by about 23% and from coral death caused by bleaching. Despite these events, it seems that sedimentation has had little effect on corals and fishes on the fringing reefs.

For developments within the Marine Park, which have the potential for increased sedimentation and damage to corals and other organisms, proponents can now expect to have to undertake detailed studies on hydrodynamics and sediment transport, including modelling, during the environmental impact assessment phase.

If approval for such projects is given, then conditions are attached to the permit to ameliorate likely effects during construction. In addition, monitoring programs are required to assess effects during construction and afterwards. The recent redredging of Heron Island harbour, and the unexpected high suspended sediment loads which resulted, has highlighted the need for more careful assessment and control of such operations. It has also highlighted the difference between public perceptions of damage and actual damage, which in turn indicates a need for better education and information of the public.

Anti-fouling:

Recent information from overseas studies on the effect of Tributyl-tin (TBT) on marine organisms has alerted the Authority to the need for caution in the use of anti-fouling biocide paints.

This is particularly important for stationary structures or vessels working in limited areas. As a general policy, the Authority prohibits the use of anti-fouling paints, ie biocides, on fixed structures. This is being introduced progressively. For vessels workirlg in limited areas, eg underwater viewing vessels, tests of "inert" forms of anti-fouling such as polyamine cured epoxy resin are being undertaken. If feasible, the use of this form of anti-fouling could be required as a condition of permit.

Oil Spills:

¡ Most oil spills in the Great Barrier Reef Region have been small and come from deliberate flushing of tanks by ships and vessels or by accidents, eg in fuel transfers on floating structures. However, the potential for a major spill from a tanker going aground remains. It is difficult to connect fuel spills from international shipping to the offending vessel and master. Where this is possible action in the form of warning letters is taken through the flag country.

For local vessels such as fishing trawlers, an educative approach has mainly been used. For operations requiring a permit (eg tourist facilities) fuel transfer and storage arrangements are assessed during environmental impact assessment and suitable controls built into permit conditions. The Authority has the responsibility for scientific coordination under REEFPLAN in the event of an oil spill in the Great Barrier Reef Region.

In general terms coral reefs are not at great risk from small spills, because of their subtidal nature. However, major spills will impact seriously and intertidal environments around islands and along the coast are thereby at risk.

22

WATER February, 1989

SUMMARY The Marine Park Authority is coming under increasing pressure to control or prohibit discharges, which are perceived to damage the resources of the Marine Park. It seems we need to develop new standards for coral reef environments. This is a new area where much information is needed on the effects of discharges. Such information is often not available in the time frame in which managers need to make decisions.

Decisions are therefore made on the likely impacts, on standards to be achieved and monitoring required on the best information available, and within time constraints. Such decisions must be realistic, with achievable conditions; all the while ensuring that the resources of the Great Barrier Reef are adequately protected.

The opinions expressed in this paper are those of the author and not necessarily those of the Great Barrier Reef Marine Park Authority or of the Commonwealth Government. â&#x20AC;˘

LEGISLATION AFFECTING WATER MANAGEMENT ON TOURIST ISLANDS L. de W. HENRY

ABSTRACT There are some 40 pieces of Commonwealth and State Legislation and numerous Local Authority By-laws applying to the provision of services and management of water quality on Tourist Islands in Queensland. These may either facilitate or restrict the development of these islands. There is provision in Commonwealth and State procedures for interested parties to contribute to the drafting of legislation and in some cases for review of or appeals against decisions made by Statutory Bodies. The correct interpretation of ¡legislation requires a knowledge of legal conventions. There is a need for changes in the law and statutory procedures to encourage greater participation by developers, managers and the community and to simplify the resolving of disputes. A one-stop shop able to deal with most legislative requirements is supported.

GOALS OF LEGISLATION The goal or purpose of legislation is usually stated as a preamble to the Bill or Act. These goals or purposes are sometimes divided into two broad classifications: (a) Facilitating and (b) Restrictive.

The former may support the development and disposition of natural resources; the latter may provide for the protection and conservation of natural resources.

Examples of the two classes of goals are: (a) "To provide for the approval of schemes of integrated resort development, to make provision to assist in the establishment, operation and management of approved integrated resort developments and for other purposes ". (Integrated Resort Development Act) (b) "An Act providing for the protection of the environment by regulating the dumping into the sea, and the incineration at sea, of wastes and other matter and the dumping into the sea of certain other objects, and for related purposes". (Environment Protection (Sea Dumping Act)).

In practice, however, these simple statements can be misleading, particularly in the case of legislation which is frequently amended.

Amendments can significantly modify the original goal. In practice, also, most environmental legislation contains both facilitating and restrictive provisions and endeavours to strike a balance between the use and conservation of resources.

The author suggests that the goal of all legislation should be to benefit the whole community.

CONSTRAINTS OF LEGISLATION After many years of involvement in drafting, interpreting and administering legislation, the author perceives a number of constraints: (a) Subjective interpretation and administration. (b) Uncritical acceptance of general statements without checking what is in the legislation. (c) Failure to obtain legal advice on critical points. (d) Lack of appreciation of the opportunities in legislation for agreements, reviews and appeals. (e) Reluctance to participate in the legislative processes. (f) Undue influence of minority groups. (g) Recent decisions of the High Court in respect to the constitutional powers of the Commonwealth Government. (h) Australia's three tier system of Government.

This paper addresses some of these constraints as the author perceives them, but restricted to Commonwealth and Queensland legislation.

24

WATER February, 1989

Leon Henry - Consultant with Scott & Furphy Pty Ltd. Formerly Assistant Director of Local Government and Chairman of the Water Quality Council Queensland.

I.eon de W. Henry

AUSTRALIA'S SYSTEM OF GOVERNMENT The State of Queensland was established in 1859 when it became a colony separated from New South Wales. The Commonwealth Government was established in 1901 by the State Governments which handed to the Commonwealth Government certain of their powers and relinquished some other powers, to form a system of Federal Government under a constitution formulated by the States.

Local Authorities in Queensland were established by the State Government to cover the whole area of the State.

Whilst the original constitution was probably appropriate at the time, changing circumstances, particularly arising from Australia's increasing participation in international affairs, have caused problems in the relationship between the Commonwealth and State Governments and, to a lesser extent, their relationship with Local Governments.

Because of the problems where each State and the Commonwealth may have separate jurisdictiifos with different or conflicting legislation, the States and the Commonwealth Government established Ministerial Councils and Standing Committees of officers. Those with a bearing on water quality, recreation and tourism are: Australian Environment Council (AEC); Council of Nature Conservation Ministers (CONCOM); Australian Water Resources Council (AWRC); Australian Fisheries Council (AFC); Marine and Ports Council of Australia (MPCA); Planning Ministers Conference (PMC); Great Barrier Reef Ministerial Council (GBRMC).

These Councils have no statutory authority but provide consultation and coordination and, from time to time, agree on recommendations for uniform legislation by the Governments concerned, examples of which appear in the Appendix.

Another Commonwealth/State body involved with water quality is the National Health and Medical Research Council. It provides guidelines for the quality of water supplies and for sewage used for irrigation and other health aspects of water quality. These documents have no standing in law, but are useful references provided one knows their origins.

In some cases, the States have voluntarily relinquished their powers to the Commonwealth. In other cases, the States have been bitterly opposed to the Commonwealth Government's setting aside of State rights.

Recent High Court judgments have extended the Commonwealth's Constitutional powers over external affairs to include legislation on internal matters relating to international agreements without the agreement of the relevant State Government.

In the case of tourist islands in Queensland, there is considerable uncertainty about jurisdiction over water quality matters. The boundaries of the State of Queensland extend some 400 kilometres into the Pacific Ocean on the east and to within a few kilometres of the Papua New Guinea coastline to the north to include off shore islands and exposed reefs and sandbanks.

Most of these lands are also included in Local Authority areas, including some Aboriginal and Torres Strait Islanders Authorities.

On the other hand, the Commonwealth Government now has jurisdiction over most of the ocean waters within the State boundary and has limited powers to influence.development of the islands, It may well be asked whether the By-laws of a rural mainland Local Authority are appropriate to a self contained, sophisticated island resort catering to international tourists and whether Canberra is the appropriate place to determine requirements for these tropic islands. The need for dual Commonwealth/ State jurisdiction may also be queried.

Fortunately, in spite of media-generated standoffs, some dedicated Commonwealth and State scientists, engineers and administrators are developing good co-operative arrangements and getting on with the job of balancing development and conservation for the common good.

PREPARATION OF LEGISLATION IN QUEENSLAND As a result of recommendations of the Committee of Review of Business Regulations (the "Savage Report"), in 1986 the Queensland Government introduced new procedures for drafting Acts and Regulations and for reviewing existing Regulations. These procedures are set out in the Queensland Legislation Manual. J.1 feature of these procedures is the requirement that, prior to drafting of the legislation affecting business, the Department concerned must prepare and make available to persons affected copies for study and comment. The Department is required to define the objectives of the proposed legislation, to assess alternatives to legislation and the impact of the legislation and to describe the proposal in detail.

The Department must consult with industry, the public, special interest groups, other Departments and, where appropriate, with other Governments. A somewhat unrealistic deadline for response of a minimum of 10 days has been set.

The Minister concerned is required to obtain Cabinet approval to proceed with the legislation. The submission is accompanied by the relevant Green Paper and an explanation of the proposal. A perceived deficiency is the lack of any requirement to include the responses to the Green Paper of affected parties and the results of the mandatory discussions. The next steps are: (a) Preparation by the Department of a draft Bill. (b) Submission of the draft Bill to the Parliamentary Counsel for redrafting as necessary to ensure that the legislation is in a proper form and legally effective. (c) Compilation of explanatory notes by the Department. (d) Submission to the Minister's Committee. (e) Submission to Cabinet for approval to introduce the Bill to Parliament. (f) Endorsement by a Government Party Meeting. (g) Arrangements for inclusion in the session program.

A Bill is a confidential document until it is distributed to members of Parliament at the First Reading. The Bill is not actually read nor does the Minister make a speech. The Minister simply moves to the effect that the Bill be printed and read. At the Second Reading, the Minister explains the purpose of the Bill, its main provisions and the reasons for them. These speech notes are also confidential until the Minister moves the Second Reading, when copies are provided to all members and the press. The debate is adjourned for a few days. On the resumption, the motion for the Second Reading is debated and amendments to the motion may be introduced. Following approval of the motion, the House goes into Committee and examines the Bill clause by clause. Amendments may be proposed and accepted or rejected. The Opposition may call for divisions on controversial issues. Whilst the debate is supposed to be limited to matters relevant to the clauses of the Bill, this is interpreted rather loosely and lots of local and peripheral issues are raised. After the Committee stage the Third Reading is usually another formality and the Bill goes to the Governor for Royal Assent after which it becomes an Act and is notified in the Gazette with the date or dates from which it commences.

The whole of the debate is recorded word for word for publication in Hansard.

Departmental advisors attend Parliament during the progress of the Bill to assist the Minister in answering questions and explaining complex provisions. To comply with Parliamentary protocol, they sit in a small alcove within the Chamber but separated from it by a railing which is aligned with the Bar which defines the limits of the Chamber and may not be crossed by non members during sittings or by members after the Division bells have ceased ringing.

Subordinate legislation such as Regulations requires a Green Paper but procedures are different. Usually the ltegulations are drafted by the Department and submitted to the Solicitor General to ensure that there is specific power in the enabling Act.

PREPARATION OF WCAL AUTHORITY LEGISLATION The procedures for the making of Local Authority By-laws and Ordinances are set out in the Local Government Act and the City of Brisbane Act. The first step is the passing of a resolution to make the By-laws or Ordinances at a special meeting of the Council. The Council must then advertize the intention to make the By-law or Ordinance and make copies available for inspection. Any person may lodge an objection, whether he resides in the local authority area or not. The periods for inspection and lodging of objections are set out in the Act, varying from 21 to 90 days. The Council must then consider all objections prior to a resolution to proceed and seek the approval of the Governor in Council. This is done by submission to the Department of Local Government with an explanatory note and a certificate of intro vires from the Council's solicitor. The Department may review the By-law or Ordinance and suggest changes before the Minister takes it to the Governor in Council. The approved By-law or Ordinance is then published in the Government Gazette. Ordinances, but not By-laws, must be tabled in Parliament and may be disallowed.

COMMON LAW In addition to State Law, water quality matters may be subject to Common Law, particularly where private interests are concerned.

CLASS ACTIONS Class actions which are frequently undertaken in the USA have so far received little recognition in Australia.

It is understood, however, that the Australian Law Reform Commission has drafted a "Federal Court (Grouped Proceedings) Bill" for consideration by the Commonwealth Government. If, as is rumoured, this is coupled with the principle of strict liability and contingent legal fees, a few cases of alleged water borne disease could put a resort island out of business. .,, APPEALS, REVIEWS, AGREEMENTS If legislation should be written and administered for the overall good of the community, it is essential that it embody mechanisms for resolving disputes and reaching compromise agreements. Unless developers, managers, administrators and enforcers are prepared to discuss and resolve their differences in an amicable and cooperative way, conflicts and stand offs will inevitably develop, with delays, extra costs and exasperations to all concerned.

Appeal provisions in Australian legislation are often restricted to persons directly involved and exclude third parties. However, most legislation also provides for appeal tribunals and courts to establish rules and/ or principles for hearings which may affect the carriage of the appeals legislation.

Where there is no formal appeal provision in the legislation, a person aggrieved by an administrative decision can still appeal to the Parliamentary Commissioner (Ombudsman) who will inquire into the circumstances, calling for the files if necessary, and satisfy himself that the legislation has been properly applied. An aggrieved person can also complain to his local member of Parliament or to the Minister or to the Premier, which again usually results in a requirement to justify the action. A member of Parliament can raise questions on the administration of legislation by way of question or during periods set aside for that purpose or during the debate on similar legislation or amendments to the particular legislation.

INTERPRETATION AND ADMINISTRATION OF LEGISLATION In the author's experience, most of the problems with legislation arise from its interpretation and administration. Few people have the ability to interpret and administer legislation in an objective, impartial way. The problem is exacerbated by the adversary situations which arise from different interpretations.

WATER February, 1989

25

The author suggests a number of classifications of people interpreting and administering legislation: • Have never read it.

• Have read it but saw only blank pages.

• Have read it but failed to understand it.

• Have read it and obtained legal or other informed advice.

• Have been involved in drafting it.

• Have legal qualifications.

• Have legal qualifications appropriate to the particular legislation.

In the interpretation and administration of legislation, it is essential to understand that, after approval by Parliament or the Governor in Council, each word and piece of punctuation is deemed to have been approved exactly as in the final Bill approved at the Third Reading. Any mistakes, omissions, etc, remain until corrected by an amending Act. Moreover, the original intention or objective is no longer relevant - only the approved wording may be implemented. The third caution concerns the meal'ling of the words - in any dispute or appeal it is the precise legal meaning of the words which is followed, not the usual meaning understood by the man in the street nor the technical meaning understood by engineers and scientists. If this presents problems to developers and .environmental groups, it can also cause frustrations to the Department which originated the legislation.

Where frequent amendments occur, such as to S33 and S34 of the Local Government Act dealing with Town Planning and Subdivision of Land, few people understand the ultimate effect of the successive amendments which refer to previous amendments as well as the original clauses.

PARTICIPATION IN LEGISLATIVE PROCESSES From the foregoing, it might be concluded that all parties concerned with management of water quality on a tourist island have the opportunity to study proposed legislation, to provide comments, objections and proposals for changes and to make representations on the implementation and administration of legislation.

In practice, there are complications. The Green Paper provisions apply to significant legislation, of which the Minister is the judge.

The Minister may decide that a Green Paper is confidential with restricted access. A Green Paper may be incomprehensible to people not conversant with the language of public servants, particularly when it assumes familiarity with other legislation or the legislation which it amends. A period of 10 days is completely inadequate to enable organizations to understand and debate the legislation and to formulate properly informed and considered submissions. Some Departments appear to be reluctant to implement the consultative procedure apparently in the belief that the receipt of comments on the Green Paper is the final step. A further problem is that Cabinet does not have to be advised of the comments, objections and submissions received.

The author's experience is that developers and managers of tourist islands have little time or inclination to participate in legislative processes until forced to do so by some crisis. Actions during crises often have unexpected results when the resulting legislation is put to the test. Continuing participation would be much more advantageous.

Environmental organizations, however, have been quite successful in their efforts to influence legislation, even where they are not directly involved as protagonists. Some of these are well informed, rational and cooperative. These have been of assistance to governments and developers in formulating water quality strategies. Unfortunately, they tend to be regarded in the same light as the more radical, publicity seeking groups which seek to stop and disrupt tourist and other developments.

The author's experience leads him to the conclusion that most people with concern for the environment accept the need for some developments and that most developers accept the need to protect and conserve the environment - especially on an island resort.

Again, experience with the Water Quality Council and other bodies whose membership includes people with different and opposing goals and opinions shows that a rewarding degree of consensus and, at worst, understanding can be achieved.

26 WATER February, 1989

CURRENT LEGISLATION AFF~CTING WATER QUALITY ON ISLAND RESORTS Tables 1 and 2 list the Commonwealth and Queensland Legislation concerned with water quality on island resorts with which the author has been involved. It may not be complete. Some legislation is specific with obvious effects. The relevance of some may seem obscure to those not familiar with the Acts, Regulations and By-laws and how they are administered.

No attempt has been made to list Local Authority By-laws, which are many and varied .

TABLE 1 - Commonwealth Legislation Affecting Management of Water Quality Australian Heritage Commission Act Environment Protection (Impact of Proposals) Act Environment Protection (Sea Dumping) Act Great Barrier Reef Marine Park Act National Parks and Wild Life Conservation Act

Protection of the Sea (Discharge of Oil from Ships) Act Protection of the Sea (Prevention of Pollution from Ships) Act Protection of the Sea (Powers of Intervention) Act Seas and Submerged Lands Act.

TABLE 2 - Queensland Legislation Affecting Management of Water Quality Aboriginal Relics Preservation Act Beach Protection Act Building Act Canals Act Clean Waters Act Construction Safety Act Essential Services Act Fisheries Act Factories and Shops Act Franchise Agreement Acts Fluoridation of Waters Act Gas Act Harbours Act Health Act Industrial Conciliation and Abitration Act

Integrated Resort Development Act Local Government Act Liquor Act Litter Act Marine Parks Act National Parks and Wildlife Act Parliamentary Commissioner Act Pollution of Waters by Oil Act Queensland Marine Act Queensland Marine (Sea Dumping) Act Radioactive Substances Act Sewerage and Water Supply Act State Development and Public Works Organization Act W~ter Act Water Resources Administration Act

SUGGESTIONS FOR IMPROVEMENTS 1. Informal reviews/ hearings as a precursor to the formal appeal process.

2. Use of performance standards instead of or in addition to specific standards.

3. Flexibility to permit approval of alternatives and entrepreneurial developments meeting essential minimum health and safety requirements.

4. Acceptance of certificates of compliance from accountable independent persons.

5. Pro-active participation by developers and managers in legislative processes.

6. Changes to Green Paper procedures to ensure that Ministers and Cabinet are informed of representations from organizations significantly affected by the proposed legislation.

7. Use of simple, clear precise English language in legislation.

8. Dissemination of legal opinions and decisions which interpret legislation.

9. Complete sections of Acts to be amended rather than odd words.

10. One-stop shops for development proposals as currently being investigated by the Queensland Minister for Local Government.

11. Grouping of legislation on subjects such as water quality into one or a small number of Acts or cross referencing.

12. Continuing exchange of views by way of seminars and • workshops.

Total Water Management on Resort Islands: Design, Operation and Maintenance G. A. NOLAN and I. R. CAMERON Geoff A. Nolan, DipCE, FIE Aust, is the Managing Director of Ullman & Nolan Pty Ltd, Consulting Engineers. He has been involved in the planning, design and construction of a wide range of civil engineering projects on Queensland Resort Islands for more than 20 years.

ABSTRACT This paper provides some background information on the diversity of Queensland resort islands and the constraints this diversity imposes on the water management scheme for resort islands, including the treatment of wastewater, and its disposal or use.

Water management on resort islands must be viewed in its totality if the often scarce water resources are to be utilized to their maximum and thereby ensure the viability of resort operations.

Geoff A. Nolan

INTRODUCTION Queensland Resort Islands · There are 24 island resorts which have been developed along the Queensland Coast from South Stradbroke Island off the Gold Coast northwards over the last 20-40 years as shown in Figure 1.

The terms 'island resort' or 'resort island' are often used interchangeably, but it is often the case in Queensland that resorts on islands are not the only occupier or landholder on an island. In some instances they may abut private land, or land held by companies or Crown land in its many tenure forms. Thus matters relating to the provision of water supply and sewerage services to a resort may affect adjacent landholdings either, for example, in the matter of water storages or for the route of effluent discharge mains.

Planning and design practices for the management of water supplies and sewage systems to island resorts must reflect the context of the full water cycle.

GEOGRAPHY Landforms Coral Cays: Few of the resort islands are located on the Great Barrier Reef and of these, three are the coral cays Lady Elliot Island, Lady Musgrave Island and Heron Island. Coral Cays are characterized by being small in area with little elevation, limited groundwater resources and rain is often the only source of freshwater.

Continental Islands: The majority of the resort islands are continental islands characterized by steep slopes, rocky outcrops and brackish water supplies. The continental islands are invariably landward of the Great Barrier Reef. Hinchinbrook Island and the Whitsunday Islands are spectacular examples of continental islands.

Other: Fraser Island (or Great Sandy Island) is the largest sand island in the world and is an unusual land form with a range of ecosystems and a number of perched freshwater lakes.

Hydrologic Cycle The resort islands in Queensland are distributed in both the tropical and the sub-tropical zones and as such the islands are subject to cyclonic influences which would represent the most significant weather influence in terms of rainfall, wind gusts and wave action.

As well as the extreme rainfall volumes associated with cyclones, the Queensland coastline is subject to a marked variability in average rainfall, particularly for the section between 18"S and 25"S. The coastline may be divided into three zones as detailed below.

VARIABILITY OF ANNUAL RAINFALL North of 18"S 18"S to 25"S South of 25 "S

Least Maximum Moderate

(18"S

= Dunk ls.)

WATER February, 1989

Ian R. Cameron

For those islands which are small in area and having little topographical relief above mean sea level there is little potential for the precipitation of rainfall in excess of that which falls in the surrounding sea. Off-shore rainfall volumes are generally lower than those for adjacent on-shore locations.

The steep slopes and rocky outcrops on the continental type islands imply that watercourses never develop to the mature stage of drainage of alluvial flats, thereby denying the possibility of large underground resources. Frequently underground supplies of water are subject to saline intrusion from the sea.

-,

-,--1

'~~

'

I

CO RA L

SEA

-l I

I'

I !

I

QUEENSLAND

& lady Elliot Island

'------]

IL

(25"S = Fraser Is.)

The variability of rainfall in the various zones makes the storage or rationing of water of prime importance so as to withstand times of prolonged drought associated with the failure of the monsoon season which generates the cyclones in the equatorial belt.

28

Ian R. Cameron, BEng, MIE Aust, is an associate engineer with Ullman & Nolan Pty Ltd, Consulting Engineers. He has worked as a design engineer on the Hamilton Island Sewage Treatment Plant Project.

0

• Fraser Island

Bribiie Island

•=!';'1:::,~, - -- -

_ BRISBANE•

---------____,,-r-·-----......,r1·---------

100 200 300

SouthStradbrobt.

. gs.

400 500km

SCALE 1 : 10,000 000

Figure 1. Queensland Resort Islands.

Source: QTCC brochure, Queensland,

Bathymetry Just as the resort islands along the Queensland Coast shown gre~t variability in terms of latitude and rainfall, the bathymetric profiles in the waters surrounding the islands also vary markedly. Deep waters are customarily found offshore of continental type islands.

Bathymetry is of particular interest in relation to access by sea to the islands (which is complicated by the large tidal range) and the construction of ocean outfalls for treated sewage effluent.

The Central Queensland coast between 20"S and 24 "S is characterized by a large tidal range of 6 metres, with generally decreasing ranges north and south of this band. The combination of deep waters and strong tidal currents aid in the dispersion of treated sewage effluents. Tests using Rhodamine WT dye or other materials, in a range of tidal conditions, are recommended for the study of the movement of effluents from any proposed outfall. For example, Rhodamine WT dye and a helicopter were utilized on Hamilton Island to study the movement of sewage effluent in Dent Passage, the receiving waters for the effluent.

TOTAL WATER MANAGEMENT Queensland island resorts are generally faced with difficulties in maintaining a reliable potable water supply for the dry season, which is also the peak tourist season.

Potable Supplies The following methods are all utilized on resort islands to provide potable water supplies: • Catching roofwater; • small dams; • bores (sometimes saline); • importation (eg by barge); • desalination.

In some instanc~s a number of different methods are employed conjunctively to maintain a reliable potable water supply.

It is generally accepted that the cheapest method of providing a water supply in increasing order of cost are: 1. Capture (rainwater tanks, dams).

2. Importation (barges, pipeline).

3. Desalination.

Desalination is not yet widely used due to the costs involved in operating and maintaining plants, although Hayman Island is largely dependent on desalinated water, and Heron Island uses desalination conjunctively with roof catchment and storage.

The concept of the ''carrying capacity'' for an island based on the water balance equation is not being accepted to date, due to pressures from resort operators to maximize resort guest numbers, but it may well be a rational method of appraising resort sizes.

Recycling of Wastewater In order to conserve as much water as possible, treated chlorinated sewage effluent is utilized as an irrigant for landscaped areas, lawns and golf courses. The savings are significant where there are large areas to be irrigated, or where a landscaped environment is required to be maintained and rainfall is scant in the dry season. However, the use of treated effluents on landscaped areas and golf courses is precluded in catchments which include surface water dams as part of the water supply scheme, due to the danger of pollution of the potable water supply. This conflict of water usage has yet to be adequately resolved in one island currently being examined for an island resort.

It may be seen therefore that from the need to balance components in a water equation for a particular island, good management requires that all the components be considered at the planning and design stages.

Wastewater Treatment and Disposal There is a marked variation in the maximum resort guest populations (30-1400) and as a consequence of this a range of different methods has been adopted to treat wastewater from island resorts. It should be noted that the staff component on resort islands may be up to 500Jo of maximum guest population.

The types of treatment plants which have been utilized are: Package Treatment Plants ("extended aeration'·')

Imhoff Tunks Oxidation Ditches The usual methods of effluent disposal are by way of ocean outfalls with or without the re-use of treated chlorinated sewage effluent as an irrigant on landscaped areas, lawns and golf courses.

The environmental sensitivity of the Great Barrier Reef requires that all proposals for the discharge of treated sewage effluent from resort islands in the vicinity of the reef or within the declared sections of the Great Barrier Reef Marine Park Authority be carefully considered by the relevant authorities, and require the approval of the Water Quality Council and the Great Barrier Reef Marine Park Authority where applicable.

DESIGN FACTORS FOR TREATl\jENT SYSTEMS Materials of construction The main islands are predominantly 'continental' islands but have limited alluvial aquifers. Generally, the supply of underground water is limited and in dry periods can suffer deterioration in both quality and quantity. For this reason resorts often have separate water systems for potable and non-potable grades.

There may be a change in quality of aquifer water, and hence effluents, because of increased seawater intrusion. This would normally be a gradual change, but has to be taken into account in the design of the plant.

The resultant high conductivity in the sewage and effluents makes electrodes impractical for level control since they short circuit. It is necessary to use float switches or a non-contact method such as ultrasonic level detection.

For structures, the durability of concrete covers and minimum cement contents has to be assessed. Hot dip galvanizing might not be an acceptable protection for steel, so that there will be a need to use stainless steels in areas with free oxygen, or high quality paint finish (tar epoxy), or tar epoxy in anoxic areas.

Type of plant The land available for construction of water and wastewater plants is often limited in area, and is therefore more suitable for extended aeration plants. These are cheaper to construct on the mainland and this is even more the c:tse on the resort islands, since they are more amenable to prefabricated construction, which is very relevant to island conditions.

However, they use more energy, which is an offset. Thus, the availability or capacity of the electricity supply may determine the method of wastewater treatment to be adopted.

Effluent quality If the population to be served is relatively low, and if discharge of effluent into the open sea, with heavy dilution, is possible, there is some scope for relaxation of the effluent quality (eg Hamilton Island). · However, if the effluent is to be re-used for landscape irrigation, it should be necessary to use tertiary treatment, since odours cannot be tolerated to any degree if the areas to be irrigated include gardens as well as broad acre golf courses. However, in general, such tertiary treatment has not yet been adopted.

Operation and Maintenance A high standard of operation and maintenance of plants is required if the resort managements are to exercise their duty of care in relation to resort guests.

Simple Imhoff, Imhoff + biological filters, and full primary sedimentation, biological filtration, followed by secondary sedimentation and sludge digestion systems are relatively simple to operate and rather tolerant of change in plant load and conditions.

A greater degree of skill is required with extended aeration/ activated sludge treatment plants to maintain the conditions necessary for the desirable bacteria and not have floating or bulking sludge problems. In this regard control and monitoring of dissolved oxygen, pH, and sludge volume index is relevant. Also, sludge age may be of significance and variation in loading due to the resort occupancy profile directly impinges on this aspect.

Fats and greases are problems to varying degrees with most treatment plants. Island resorts are based on restaurant style catering WATER February, 1989

29

and seem to have, as a result, greater problems with fats and greases than normal urban development. This can largely be overcome by having adequately designed ·and well-maintained grease traps. Emphasis is on maintenance and it would be reasonable, on a tourist resort, for the treatment plant operator to be responsible for the day-to-day operation and maintenance of grease traps.

Mainland sewerage systems are generally controlled by local authorities with management and specialized staff being employed to operate the installations. It is necessary that resort managements regard their installations in a similar manner. In this regard it is relevant to report a reluctance in a number of instances to employ well-trained staff and it may be necessary for central government to consider the implementation of statutory legislation to control the situation.

The high turnover of staff on many resort islands creates problems in maintaining the necessary supervision of the operation and maintenance of plants.

Testing Experience has been gained during design, construction and maintenance of sewage treatment plants in remote mining towns which are not unlike island situations regarding remoteness, and difficulty in obtaining qualified treatment plant operators.

In consequence, the following are considered to be minimum testing requirements for such sewage treatment plants: - 5 days Biological Oxygen Demand (BOD ,) - Suspended Solids (SS) - Mixed Liquor Suspended Solids (MLSS) - Acidity/Alkalinity (pH) - Residual Chlorine Settleability of Effluents - Total Nitrogen - Temperature It is essential that testing be carried out and records kept for evaluation of the plant performance and related to sewage flows into the plant.

SOME EXAMPLES Hayman Island On Hayman Island an Imhoff Tonk which was in a poor state of repair and providing poor quality effluent was replaced by an Oxidation Ditch type treatment plant. This has been operating satisfactorily since construction in the early 1980s. (Ullman & Nolan, 1980) South Molle Island An Oxidation Ditch type plant has been recommended for South Molle Island in order to eradicate the odour problems associated with the existing plant.

Hamilton Island An Imhoff Tonk sewage treatment plant was designed for Hamilton Island but not proceeded with because of cost considerations and the imminent connection of mainland power to the island.

An Oxidation Ditch sewage treatment plant is currently being designed for an equivalent population of 5000. An ocean outfall will discharge treated sewage effluent to Dent Passage. (Ullman & Nolan, 1988)

CONCLUSIONS Total Water Management on resort islands requires an understanding of the total water balance for a resort and required detailed data on guest and staff numbers, associated facilities and · available resources.

Due to the diversity of many of the natural factors which would affect the likely water balance equation each resort island needs to be assessed invidivually.

The effect a particular island resort proposal may have on adjoining landholders bears special consideration since many Queensland islands are National Parks totally or in part. There are environmental difficulties in placing water supply dams within National Parks or discharging wastes to Marine P.arks.

30

WATER February, 1989

There may be other island resorts devell,ped in Queensland in the future and these, if they adjoin National Parks or Marine Parks, will require that the natural environment be safeguarded from pollution from island resorts. The operation and maintenance of the sewage treatment plants could be the crucial matter to be addressed when considering the long term effect of an island resort upon the natural environment.

The licensing of sewage treatment plant operators and stringent monitoring procedures by plant operators and the relevant authorities would appear to be the minimum requirements to ensure that the natural environment is not degraded by island resorts. It must be remembered that the charm and appeal of many islands is linked to the quality of the surrounding natural environment.

ACKNOWLEDGEMENT The authors thank Mr K. T. Mienert, Director, Ullman & Nolan Pty Ltd for supplying detailed information on the Hayman Island Sewerage Scheme and for providing design notes which have been included in this paper.

REFERENCES QUEENSLAND TOURIST AND TRAVEL CORPORATION (QTTC) (1986), Queensland Australia (Brochure). Brisbane.

ULLMAN & NOLAN PTY LTD, CONSULTING ENGINEERS (1980), Preliminary Report to Proserpine Shire Council. Re: Hayman Island Sewerage Scheme. Mackay.

ULLMAN & NOLAN PTY LTD, CONSULTING ENGINEERS (1988), Hamilton Island Enterprises, Design Summary Report, Hamilton Is• land Sewerage Scheme Upgrading. Brisbane.

NATIONAL ENVIRONMENT ENGINEERING CONFERENCE Planning for Environmental Change: The Greenhouse Effect Sydney March 20-22, 1989 Information: Institution of Engineers 11 National Circuit Barton ACT 2600 Phone: (062) 706549

GIARDIA CONFERENCE 'Backpacker's disease' is already present in Australian streams.

Agencies responsible for catchment management, outdoor recreation, protection of native animals face new issues.

April 21, 1989 Canberra Information: Shirley Kral, C.C.E., Australian National University GPO Box 4, Canberra 2601 Phone: (062) 494580

Manganese Removal: A Model of Cooperative Research D. R. Dixon, L. I. Sly, T. D. Waite, B. Chiswell and G. E. Batley ABSTRACT The apparently increasing occurrence of manganese-related problems in many of Australia's potable water supplies stimulated the formation in 1986 of a national consultative committee of water scientists with experience in such dirty water problems. This committee has now been involved in the coordination of a variety of investigative programs into the nature of the dirty water problem and the removal of _manganese from drinking waters.

Aspects of source water quality, treatmep.t plant operation and reticulation system maintenance which are relevant to the issue of manganese related water quality problems are discussed.

INTRODUCTION The presence of excessive levels of manganese in drinking-water is undesirable because it leads to manganese deposition on pipe surfaces and to water of poor aesthetic quality. The appearance, taste, and staining characteristics of manganese-related dirty water are unacceptable to consumers.

Complaints occur when manganese oxide deposits slough off pipe surfaces and cause staining of equipment, fixtures, swimming pools and laundry.

An increasing number of Australian communities have, or are beginning to experience these problems. In fact, recent investigations into dirty water problems on the Gold Coast in southern Queensland indicated that consumer complaints occurred when manganese concentrations in the treated water exceeded 0.02 mg/ L (Sly, 1987). Similar dirty water problems have been reported in the Pine Rivers Shire north of Brisbane, in the Wyong Shire on the central New South Wales coast, in parts of the Sutherland Shire and the Wollongong region south of Sydney, in Melbourne and in t~e Barossa region of South Australia. It should be recognized that the problem is not unique to Australia with, for example, roughly 40 per cent of public water supplies in the United States exceeding recommended levels of manganese (AmWWA, 1987).

Given the apparently increasing severity of manganese-related water quality problems in Australia and the lack of coordinated scientific support available to State and local government authorities in connection with these issues, a consultative committee of water scientists with experience in such dirty water problems was formed under the auspices of the Gold Coast City Council. This committee (made up of the co-authors of this paper) has since provided technical advice to the Gold Coast City Council and the Wyong Shire Council over the last two years and has been involved in the coordination of investigative 32

WATER February, 1989

D. R. Dixon, BSc, PhD, FRACJ, Principal Research Scientist, CS/RO Division of Chemicals and Polymers.

L. l Sly, BSc, PhD, MASM, Chief Professional Officer, Department of Microbiology, University of Queensland.

D. R. Dixon

T. D. Waite, BSc, MAppSc, PhD, ARACJ, Senior Research Scientist, ANSTO.

B. Chiswell BSc, PhD, FRACJ, Senior Lecturer, Department of Chemistry, University of Queensland.

T. D. Waite

B. Chiswell

G. E. Batley, BSc, MSc, PhD, FRACJ,

Senior Principal Research Scientist, Centre for Advanced Analytical Chemistry, CS/RO Division of Fuel Technology.

G. E. Batley

programs into removal of manganese from drinking waters.

It should be emphasized that while the onset of Mn-related dirty water problems sometimes coincides with an increase in Mn level of the raw water, often the causes are much more subtle. Even in those regions where laundry staining has been severe, the concentrations of manganese in the supply water has not exceeded the National Health and Medical Research Council recommended value of 0.05 mg/ L (NHMRC, 1980). Rather the build-up of manganese within the system has occurred over a longer period, followed by a change in conditions which cause its sudden release. The challenge facing the committee was to determine the reasons for both effects and in combination with council staff to offer immediate solutions. This paper briefly reviews the results of these efforts and highlights the value of such cooperative research. For more detailed accounts of the work readers are referred to individual publications by the authors (Proc AWWA Conf, Canberra 1989).

WATER SUPPLY AND DISTRIBUTION SYSTEMS Aeration is now recognized as an effective way of minimizing the release of man-

ganese from sediments and is being used increasingly in Australian reservoirs (Loos, 1987). 1\vo additional benefits are the maintenance of uniform water quality throughout the seasons and the maintenance of maximum residence time within the reservoir. However, it is not always possible to endure that manganese concentrations in raw waters are below the levels recommended for drinking waters and, in such instances, removal methods must be implemented within the treatment plant.

Common methods of treatment involve the oxidation of soluble Mn(II) to insoluble Mn(IV) using relatively powerful oxidants such as chlorine, chlorine dioxide and potassium permanganate followed by removal of the manganese precipitates by filtration, sometimes preceded by flocculation and, in some instances, sedimentation.

Manganese can enter the distribution system in three major forms, as soluble Mn(II) in the event of inadequate or non-existent oxidation, as Mn(IV) oxide particles or in particulate form but complexed with aluminium, calcium, iron and silica. Manganese in the distribution system can then be deposited either chemically as an oxide coating or microbiologically as a manganese-depositing biofilm.

Dirty water problems are caused by the detachment of these deposits.

THE GOLD COAST SYSTEM The Gold Coast distribution system is shown in Figure 1. Following the commissioning in 1983 of the Molendinar water treatment plant which draws water from the Hinze Dam, sporadic occurrences of manganese-related dirty water have occurred. The Molendinar water treatment plant is a 100 ML per day plant using alum coagulation, sedimentation and sand filtration followed by disinfection with chlorine and chlorine dioxide. Since January 9th, 1986, settled water has been treated with chlorine dioxide prior to filtration to oxidize and remove manganese.

A manganese oxide coating was found in areas of the reticulation system near the treatment plant with finite residual chlorine levels, and when manganese levels had continuously exceeded 0.02 mg/ L for a few days. The rate of deposition depended on the concentrations of manganese, chlorine · and chlorine dioxide (Sly, Hodgkinson and Arunpairojana, 1988).

Tests also indicated that a manganesedepositing biofilm occurred in areas of the distribution system with insufficient residual chlorine levels to control microbial growth. The composition was similar to manganese oxide coating except for the presence of high numbers of viable micro organisms actively involved in the deposition of manganese. The dominant manganese-depositing microorganism in dirty water samples and biofilm was the budding hyphal bacterium Pedomicrobium manganicum. This organism has also been isolated from distribution systems experiencing dirty water problems in Nambour, Warwick, Wyong and Melbourne. Biofilm developed rapidly in areas without adequate chlorination near the extremities of the distribution system but could be controlled by a residual free chlorine level of 0.2 mg/ L. Detachment of these deposits occurred in two ways. Firstly, scouring of the manganese oxide coating from mains near the treatment plant resulted from a small increase in flow rates. The transition from overnight to daytime velocities caused a dirty water event.

HINZE

Secondly, penetration of chlorine into an area of the distribution system which had been insufficientJy chlorinated to control microbial growth caused the detachment of manganese-depositing biofilm. Such areas with intermittent chlorination usually were near the extremities of the system.

Chlorine-affected biofilm was less resistant to increased water velocities than normal biofilm and behaved in a manner similar to manganese oxide coating.

Dirty water caused by sloughing of manganese-depositing biofilm was readily identified by the presence of large numbers of budding hyphal bacteria. Events usually occurred sporadically in areas with intermittent chlorination, and were independent of manganese levels immediately prior to the event.

On the other hand dirty water caused by scouring of manganese oxide coating was more generalized, not characterized by high numbers of bacteria and was directly related to manganese levels immediately prior to the event. Substantial consumer complaints occurred at 0.05 mg/L manganese and were not eliminated until levels were continuously below 0.02 mV L. However levels of 0.02 mg/ L for 2-3 days or 0.03 mg/ L for 1-2 days resulted in a small number of consumer complaints.

THE WYONG SYSTEM The Wyong Shire Water Treatment Plant located at Mardi Dam, near Wyong on the Central Coast of NSW (as shown in Figure 2) was commissioned in December 1982.

It incorporates a direct filtration process with a design capacity of 70 ML day-•. The raw water input to the plant is taken from a storage dam of 7400 ML capacity with a surrounding catchment area of over 42 000 ha. Mardi Dam is aerated to keep the water reasonably mixed during the period September to May. Periodically, a small number of water consumers in the Wyong Shire received dirty water. The consultative committee was retained to oversee the following major activities: - to monitor manganese and other

DAM

TOTAL STORAGE 41 800 MQL .

SA FE

TOTAL

YIELD

STORAGE

9080 MQL.

~;F: 1/~~~~AY .__,/

relevant parameters throughout the system; - to investigate wa'ter treatment processes at Wyong with a view to optimizing the removal efficiency for manganese, iron and organic substances; and - to investigate the nature and extent of biofilm growth throughout the reticulation system.

The results (Waite, 1989) showed that: • manganese in the aerated Mardi Dam is generally present in an oxidized, particulate form .

• although artificial destratification has resulted in a more uniform and improved water quality, relatively high concentrations of manganese in raw waters supplied from Mardi Dam were occasionally observed necessitating removal fu the treatment plant.

Concentrations over the past year have been very low (<5ppb).

• if water containing soluble Mn(II) species was to reach the treatment plant then routine prechlorination is unlikely to achieve significant oxidation at the typical pH values of raw water from Mardi Dam. • in contrast to chlorine, potassium permanganate induces rapid oxidation of manganese(II) ion in raw waters from Mardi Dam with a half-time of about two minutes at pH 6.5 (Khoe, 1989). Permanganate is also an effective oxidant of organic compounds and may be used to minimize taste, colour and odour problems.

Given these attributes, it is recommended that potassium permanganate dosing be continued at times of high manganese(II) content in raw waters.

• with better analytical procedures, more accurate data could be obtained (Chiswell), 1989). , • biofilm monitoring points were established at the water treatment plant where adequate chlorination occurred and at Bateau Bay whqre chlorine residuals were zero during the study period. The results from these experiments confirmed that only low levels of manganese deposition occurred near the treatment plant, but that considerable deposition occurred at Bateau Bay towards the end of the reticulation system.

The manganese-depositing bacterium Pedimicrobium Manganicum was isolated and cultured from biofilm at Bateau Bay and also observed in Wyong dirty water samples.

• to test the effectiveness of chlorination in controlling manganese-depositing biofilm in the distribution system, biofilm which had been established at Bateau Bay was subjected to chlorination by dosing with sodium hypochlorite at 9.2 mg/L chlorine. The effect of chlorine was seen in two ways. Initially, the appearance of the biofilm was brown, even and firmly adherent. However, after three days the biofilm became loose and patchy as the chlorine damaged biofilm detached. This was reflected in the level of deposited biofilm manganese remaining on the surface. There was no difference after one day but after 3-6 days approximately 50% of the biofilm was removed. Under normal operating conditions of fluctuating flow rates a greater detachment would be expected.

CONCLUSIONS Figure 1. Schematic: Gold Coas_t Water Supply System.

Dirty water problems associated with the presence of high concentrations of mangaWATER February, 1989

33

KANANGRA

(23 km)

HALEKULANI

stallation of supplewentary chlorinators at all intermediate reservoirs.

To physically remove existing deposits a mains cleaning program starting near the water treatment plant and moving toward the extremities is needed.

Finally, the authors wish to recommend this type of multi-disciplinary task force as an innovative solution to the management of water quality problems.

(17 km)

ACKNOWLEDGEMENTS

THE ENTRANCE (3 km)

The above conclusions have been reached as the result of substantial monitoring programs, both chemical and microbiological.

To amass and process the resultant data has only been possible with the enthusiastic cooperation of staff of both councils at all stages of the projects. The authors wish to acknowledge the support of the Gold Coast City and Wyong Shire Councils and by colleagues at our respective institutions.

(14 km)

REFERENCES

While manganese levels entering the distribution system remain less than 0.02 mg/ L chemical deposition should not be a problem. In the event of higher influent concentrations the use of potassium permanganate is recommended.

Chlorination levels in a water distribution system with potential manganese problems should be sufficient to control the growth of manganese-depositing biofilm while minimizing the formation of manganese oxide coating. The WHO and NHMRC/AWRC recommended range of 0.2-0.5 mg/ L chlorine is adequate. Areas of the reticulation system with widely varying chlorine levels should be avoided by in-

ALDRIDGE, P., CHISWELL, B., LEIGH, M. K., O'HALLORAN, K. R. and PASCOE, M . (1989) .

Automated colorimetric method for the estimation of manganese in raw waters. Water, Journal of the Australian Water and Wastewater Association , in press.

AmWWA (1987). Research needs for the treatment of iron and manganese. Report of the AWWA Trace Inorganic Substances Committee. J. AWWA, Vol. 79, 110-122, AWWA (1989). Proc. 13th Fed. Conv., Canberra, - Khoe, G. and Waite, T. D. (1989) . Manganese removal from Wyong water supply.

- Sly, L. I., Hodgkinson, M. C. and Arunpairojana, V. (1989). The control of manganese deposition and 'dirty water' in the Gold Coast water distribution system.

- Waite, T. D., Sly, L. I. , Khoe, G., Dixon, D. R., Chiswell, B. and Batley, G. E. (1989). Manganeserelated water quality problems.

LOOS, E. T. (1'187). Experiences with manganese in Queensland water supplies. Water, Vol. 14, 28-31, 37.

NHMRC (1980). Desirable quality for drinking water in Australia. National Health and Medical Research Council and the Australian Water Resources Council, Australian Government P ublishing Service, Canberra.

SLY, L. I. (1987). Investigation into biological manganese oxidation and deposition in the Gold Coast water distribution system. UniQuest Limited, University of Qld. SLY, L. I., HODGKINSON, M. C. and ARUNPAIROJANA, V. (1988). Effect of water velocity on the early development of manganese depositing biofilm in a drinking-water distribution system. FEMS Microbiology &oloby, Vol. 53, 175-186.

WAITE, T. D., SLY, L. I. , KHOE, G., DIXON, D. R ., CHISWELL, B. and BATLEY, G. E., (1989) . Manganese related water quality problems in the Wyong Shire region of New South Wales, Wyong Report, â&#x20AC;˘ (1989).

AUSTRALIAN CHEMICAL SPECIALTIES MANUFACTURERS ASSOCIATION

U.N. ENVIRONMENTAL PROGRAM

Third National Convention and Exhibition

THIRD INTERNATIONAL CONFERENCE

OURIMBAH (8 km)

BATEAU BAY

Wcr WYRRABALONG

(12 km)

(14 km)

Figure 2. Schematic: Wyong Shire water distribution system.

nese in potable waters appear to be occurring increasingly frequently in Australia with consumer complaints arising when manganese-rich biofilms slough off water distribution pipelines. It is apparent that in a large number of distribution systems throughout Australia significant deposits rich in manganese which, at some stage (under the impact of increased flows, increased inputs of these oxide-forming elements, varying residual chlorine levels or simply through the slow, gradual buildup of deposits) will begin releasing these troublesome materials to consumers. Optimal procedures of reservoir and reticulation system management and treatment plant operation for the removal of these elements are very much case-specific and require an understanding of the chemical,

A.P.M.A.

Seminar Nett Positive Suction Head April 18th, 1989 Melbourne Information : APMA GPO Box 817 Canberra ACT 2601 Phone: (062) 47 2233

34

WATER February, 1989

biological and engineering aspects of the problem.

16th July, 1989 -

18th July, 1989

Regent Hotel -

Sydney

Hazardous Waste Management September 10-13, 1989 Pittsburgh, USA

Information: AUSAE Conference Services, Level 3, 49 York Street, Sydney NSW 2000, Phone (02) 262 1568, Fax: (02) 290 1985, Telex: AA121515

Information: NUS Corporation Park West Two Pittsburgh PA 15275 USA

An Automated Colorimetric Method for the Estimation of Manganese in Raw Water P. Aldridge, B. Chiswell, M. K. Leigh, K. R. O'Halloran and M. Pascoe ABSTRACT This work describes a colorimetric technique for the estimation of manganese in raw waters which we believe is superior to any of the three main colorimetric methods currently in use for the estimation of this metal.

The method has been thoroughly tested over a period of six months using dam water samples, and for over 12 months has been used as an automated method for the analysis of raw water manganese.

The limit of detection of the technique is put at 5 ppb . , while its calibration curve over the concentration range 5-1000 ppb, has a correlation coefficient of 0.9998.

Some comments upon the specification of the manganese in the dam water, which is measured by the method, are offered.

INTRODUCTION Colorimetric determination of metal ions in solution has long been a popular analytical technique. The method's chief advantages are to be found in sensitivity of detection, cheapness of equipment, and in ease of adaptation to automatic analysis by use of either segmented or non-segmented flow equipment.

Colorimetric methods for the determination of manganese are legion 1 , but few of the methods published have been extensively tested in environmental situations over a long period such as that reported here .

The three major colorimetric methods' for determination of manganese in solution are those which are based upon: (i) production of purple permanganate ion by oxidation of the manganese (ii) the formation of a brown coloured formaldoxime manganese complex (iii) the formation of a deep red coloured 2-pyridylazonaphthol (PAN) - manganese complex.

Although all three methods can be adapted to automatic detection methods, (i) suffers from a lack of sensitivity, and often requires the use of 5 cm pathlength spectrophotometric cells. On the other hand, both (ii) and (iii) possess detection limits down to approximately 15-20 ppb of manganese, but have been found to often give manganese results, on raw water samples, which diverge markedly from those obtained by atomic absorption spectroscopy3.

Given that treatment for manganese removal in potable water plants is often considered desirable when the metal concentration reaches 40-50 ppb, (although some authorities eg. the Gold Coast City Council are currently ensuring that their manganese levels are no more than half these limits), we have developed a colorimetric method which gives excellent, consistent results for manganese in raw water at levels greater than 10 ppb .

The method, which uses the colorimetric reagent a, (3, -y, o-tetrakis (4-carboxyphenyl) porphine (T-(4-CP)P), has been adapted from work reported by Ishii and co-workers• , who used the reagent in analysis of manganese in tea-leaves. It has been very comprehensively tested in our laboratories over two years by comparative analysis using both atomic absorption spectroscopy (AAS) and electron paramagnetic resonance spectroscopy (EPRS), and has been in use for over a year in an autoanalyser unit at North Pine Dam, Brisbane.

EXPERIMENTAL DETAILS Preparation of Reagents T-(4-CP)P was prepared directly by refluxing a propionic acid solution, 0.24M in both 4-carboxybenzaldehyde and pyrrole, for 2 hours•. Upon cooling, purple crystals of T-(4-CP)P separated out, these were recrystallised from a methanol/chloroform mixture.

Barry Chiswell

Michael Leigh

Kelvin O'Halloran

Barry Chiswe/1 is a Senior Lecturer in ChemiJstry in the Department of Chemistry, University of Queensland, St. Lucia, Queensland 4067; both Kelvin O'Hal/oran and Michael Leigh are currently enrolled in the same department in higher degrees.

Mark Pascoe is Treatment Research Specialist in the Scientific Services Section of the Brisbane City Council, Rock/ea, Queensland 4106, while Phil Aldridge is a chemist in the same section.

Mark Pascoe Phil Alridge photograph unavailable

T-(4-CP)P solution. (2 x J(J 4M). Dissolve 79.1 mg of T-(4-CP)P in 5 ml of 0.1 M sodium hydroxide and dilute to 500 ml with water; store in an ambet glass bottle.

Cadmium (II) solution . (6 x 10-•M). Dissolve 0.0505 g of cadmium (II) chloride in 500 ml water.

Borate buffer. (pH 8.0/ 0.15 M in imidazole). Place 50 ml of 0.025 M (9.525 g 1- 1 ) sodium tetraborate in a 100 ml volumetric flask. Add 20 ml of 0.1 M HCl. Add 1.0212 g of imidazole in 25 ml of water. Adjust pH to 8.0 using 0.1 M HCl. Make up volume to 100 ml.

Analytical Procedure (Autoanalyser) The autoanalyser used was from Chemlab Instruments, U .K. A schematic diagram of the configuration of the analytical instrumentation is shown in Figure I . Samples for on-line analysis of water at various stages of treatment could be drawn off by sequential operation of the solenoid valves; in a later set-up which analysed only for manganese in the raw water this valve system was not used. In the case in which sequential analyses were undertaken, the operation of the solenoids and the collection of data from the colorimeter were by use of a microprocessor (Analytical Instruments, AIM 300, Strathpine, Queensland). Where only the raw water manganese was analysed, the data was collected on a chart recorder installed in the control room of the treatment plant.

The microprocessor controlled system included a recalibration step in the procedure. The other system was found to require manual calibration only once per week, by which time the baseline drift had reached no more than I 007o . The manual recalibration procedure included a water flush of the manifold system, although deposition in the analyser unit was not found to be a problem.

Black tubing, and a blackened storage bottle were used to contain the porphyrin ligand to prevent decomposition of the ligand in light. Equal volumes of the cadmium chloride and buffer solutions were mixed in a storage bottle for this feedstock to the analyser.

WATER

February, 1989 35

Filtration 3. 0

Filtration was through either 0.45 µm or 0.01 µm membranes, and was undertaken as soon as possible following sample collection. Use of the 0.01 µm membranes was coupled with an ultrafiltration unit from Sartorius.

2. 50

2. 0

Statistical Analysis The results obtained upon analysis of like samples were analysed by calculating the correlation coefficients (r) using the colorimetric method results as experimental results, and the AAS and EPRS results as reference results.

1. 50

1. 0

r

I 0. 50

_ .,,. '

'

I

- ~ ....... ; .,.

I

.._ _./

\

\ \

I

'... .....-,..~.~..,._,....,.-=::.:::.;.~~-.::::.:::--·~ · . ·.:. .:. :. ·:.:-:.__ 0. 0

.

.

s

"' "'

"' "'

"'

'I( AVELENGTH

___j

Cn'l'I)

Figure 1. Schematic diagram of autoanalyser.

Analytical Procedure (non-automated) Place 10 ml of sample solution containing manganese into a 25 ml volumetric flask which has been painted black except for 0.5 cm either side of the volume mark. Add 1 ml cadmium(Il) solution, 1 ml of borate buffer solution and 3 ml of T-(4-CP)P solution, then dilute to the mark and mix thoroughly. After 5 mins measure the absorbance at a wavelength around 469 nm.

Atomic Absorption Spectroscopy (AAS) Determination of soluble manganese by AAS was carried out by acidifying solutions to pH 2 by addition of concentrated hydrochloric acid, and measuring on a Varian AA875 spectrometer using the 279.5 nm emission line and an air-acetylene flame. Calibration of the apparatus was by use of standard solutions obtained by suitable dilution of a 1000 ppm spectroscopy standard solution (Aldrich).

RESULTS AND DISCUSSION Absorbance Characteristics Spectra of: (a) - 2.4 x 10-5 M aqueous solution of T-(4-CP)P, (b) aqueous solution containing T-(4-CP)P and cadmium (II) chloride

both present at 2.4 x 10-5 M concentration, (c) - 2.4 x 10- 5 M aqueous solution of T-(4-CP)P with 1000 ppb manganese (II) nitrate added, are shown in Figure (2). The sharpness and intensity of the absorbance peaks and the bathochromic shift of the manganese (Ill) porphyrin peak at 469 nm indicate a very favourable situation for colorimetric analysis.

Two calibration curves for manganese standards for the porphyrin colorimetric method were obtained over the ranges 5 to 50 and 50 to 1000 ppb; the correlation coefficients for these calibrations were 0.9998 and 0.9999 respectively, while the correlation coefficient for calibration over the range '5 to 1000 ppb was 0.9998.

Correlation coefficients for comparision of the colorimetric method with the two reference techniques are shown for various dam depths in Table 1; samples were filtered through a 0.45 µm filter before analysis in each case, and manganese concentrations ranged between 15 and 1200 ppb.

Table 1. Correlation coefficients (r) for the comparison of colorimetric and reference analysis methods at four dam depths.

Water Depth (m)

r values (15 analyses)

Electron Paramagnetic Resonance Spectroscopy (EPRS) Full details of the use of EPRS to determine Mn titatively are given elsewhere 5 •

2

•

12 15 18 21

aq quan-

Color. V AAS

Color. V EPRS

0.9978 0.9916 0.9683 0.9737

0.9936 0.9772 0.9656 0.9331

Sampling

The correlation coefficients for the pooled data for all four depths for these same comparisons were found to be: Sampling for non-automated work was by use of a double(i) 0.9904 for the colorimetric V AAS comparison ended Kemmerer-type, depth sampler; samples being stored in (ii) 0.9766 for the colorimetric V EPRS comparisons. polythene bottles which had been acid-soaked and then wellwashed with distilled water.

PERISTALTIC~ Sampling was undertaken at 3 metre inIECOIIDER FLOW RATES ( ml/-) tervals in the dam profile down to 21 m on 0.32 All SOLENOI> 15 different days, approximately seven COLOll9ETI:II :SO T\el COL VALVEs2.00 SAMPLE I ...... .......... days apart, over the period 18th February FLOW CELL to 3rd June, 1987. Although preliminary 0.10 c~•BUFFEA I PROCESSOR 15work carried out during a similar period in 0.23 POIIPt9E FILTERS 1986 had indicated that the method was 499Nn 1.00 DEBLIIIILER TO WAITE applicable over the whole depth profile, I the levels of soluble manganese, i.e. 0.45 µm filterable, during the test period were 2.00 TO WASTE normally less than 10 ppb down to the 12 I m depth. Thus the statistical work reported here only applies to readings at the 12, 15, 18 and 21 m depths, i.e. below Figure 2. (a) - Aqueous solution of 2.5 x 10-5 M T-(4-CP)P buffered at pH 8.0 (b) the oxycline. However, the automated Aqueous solution of 2.5 x 10- 5 M Cd(Il)T-(4-CP)P buffered at pH 8.0. (c) Aqueous analysis work indicates that the method is solution of 2.5 x 10- 5 M Cd(Il)T-(4-CP)P to which has been added Mn2+ to a successful for upper level waters. concentration of 7.3 x 10-• M (400 ppb).

--

I=

-

36

WATER February, 1989

~

The colorimetric method is clearly as accurate as flame AAS for 0.45 µm filtered raw water. This observation is supported by comparing results obtained from the autoanalyser chart readout and samples taken at the same time from the filtered raw water, which were subsequently analysed by AAS. Table 2 shows results obtained over a two-week period from 5-5-87 to 18-5-87 . As the sample for AAS was not taken at a particular recorded time, although always between 8 am and 12 noon, the results from the autoanalyser are quoted over the range of values pert.aining during the time period shown.

Table 2. Comparison of manganese analysis results by autoanalyser and AAS Date

Time Period (am)

5-5-87 6-5-87 7-5-87 8-5-87 9-5-87 10-5-87 11-5-87 12-5-87 13-5-87 14-5-87 15-5-87 16-5-87 17-5-87 18-5-87

10.30-12.00 am 8.30-12.00 8.00-12.00 8.00-12.00 8.00-12.00 8.00- 12.00 8.00-12.00 9.00-11.00 8.00- 12.00 8.00-12.00 8.00-12.00 8.00-12.00 8.00-12.00

Mn concentration Auloanalyser 14-16 pump off-line 21 -24 23 2- 6 2- 6 4- 10 2-12 plant off-line 7-15 8-12 0- 2 0 0- 8

(ppb)

AAS 10 23 21 0 II

20 9 4 12 0 5 5

Unfortunately, although May is a month of the year in which high soluble manganese may occur in the raw water from North Pine Dam, no concentrations of the metal above 30 ppb were observed during this month. Thus, the autoanalyser, although successfully monitoring the raw manganese, did not give results high enough to warn the treatment plant operator of the need to commence permanganate dosing.

Such a need has been signalled by this monitoring process more than once during the period (over one year) the analyser has been in continuous operation. However, such occurrence is rare enough to ensure that it has not been possible to correlate high ( > 50 ppb) manganese concentrations, as determined by the autoanalyser, with samples taken from the raw water and analysed

by AAS .

Interference measurements The correlation between results obtained by the colorimetric and the EPRS methods is less satisfactory, with EPRS giving lower values for manganese than either the AAS or colorimetric technique as one proceeds to greater depths in the dam hypolimnion, i.e. EPRS has a determinate error. To understand the reason for this error it should be noted that EPRS gives a figure for Mn2+aq, whereas AAS gives a value for Mn2+aq plus any manganese solubilized by acid treatment. Other work 6 on North Pine dam water has shown that the major 0.45µm insoluble material in the hypolimnion is MnCO3, and that the concentration of this species increases down the depth of the hypolimnion.

Some of this material passes through a 0.45 µm filter and will increase the AAS acidified result, but not the EPRS value upon unacidified samples. It is interesting to note that the colorimetric method also appears to analyse for this very fine MnCO 3 although the analysis is buffered to pH 8.

The passage of some fine particulate manganese, which is not in the form of Mn 2 •aq, through the 0.45 µm membrane filter is confirmed by ultrafiltration work using 0.1 µm membranes . Such filtration yields a filtrate containing only the Mnl+aq form of manganese; such filtrates all have the same concentration of manganese whether analysed for by AAS, EPRS or the colorimetric method'· ".

Depending upon a number of climatic factors, the particulate material in the dam epilimnion can possess widely variable amounts of manganese (II) carbonate, adsorbed Mn2+ ions and various manganese (II) and manganese (III) oxides as the species of manganese present. Clearly, the colorimetric method here described will include most if not all of the MnCO 3, as well as adsorbed Mnl+ ions in the manganese figure; we believe, although we_ have not conclusively proven it to be so, that the manganese oxides do not react with the porphyrin ligand.

Replicate measurements It follows that if the raw water has a relatively high load of particulate manganese, the colorimetric method here described will include some of that material in the 'soluble' manganese analysis.

We have undertaken replicate colorimetric manganese analysis on samples from the epilimnic region, both before and after 0.45 µm filtration. The reduction in manganese values has never been greater than 4%; however, it should be noted that 0.45 µm insoluble manganese during the period studied did not exceed 40 ppb, (in the epilimnion), and was normally of the order of 10-15 ppb throughout the dam profile .

It should be observed here that, although this colorimetric technique will incorporate some 'insoluble' manganese in the result, it is no more a problem here than it is in virtually any technique. We have found that even EPRS work, which analyses for Mn 2•aq ions only, will give different results on the same samples depending upon the porosity of the membrane filter used, viz. 0.45 µm or 0.01 µm. Any analytical technique used on environmental samples, that attempts to distinguish species of the analyte under study, will be effected by changes in the environmental matrix and by sample pretreatment.

There is evidence• that a high level of iron in the sample will interfere with the method, and this possibility should be assessed prior to adoption of the method; iron has not been found to be a prcn,lem in our work at North Pine Dam, where soluble iron values during the test period were for some samples in excess of 1 ppm.

ACKNOWLEDGEMENTS The authors acknowledge the help and support of the Brisbane City Council in undertaking this work. Financial support for the work was also received from the Queensland Department of Local Government and the Australian Water Resources Advisory Council.

REFERENCES I. CHISWELL, B., RAUCHLE, G., PASCOE, M. (1988) . Colorimetric methods for the determination of manganese. Talanta, in press.

2. MARCZENKO, Z. (1986). Separation and spectrophotometric determination of 1 elements. Ellis Horvvood, Chichester.

3. CHISWELL, B., O' HALLORAN, K. R., in preparation.

4. ISHII, H ., KOH, H., SATOH, K. (1982). Spectrophotomeric determination of man ganese utilizing metal ion substitution in the cadmiuma,/3 ,-y ,o-tetrakis(4-carboxyphenyl)porphine complex, Anal. Chim .Acta. 136, 347-352.

5. CHISWELL , B. , MOKHTAR, M. B. (1987) . Specification of manganese in fresh water -I-Use of EPR Studies, Talanta, 34, 307-11.

6. CHISWELL, B., JOHNSON, D., ZAW, M ., unpublished work.

7. O' HALLORAN, K. R. (1987). Colorimetric determination of manganese ,n freshwater systems, BSc. Honours Thesis, Univ . of Q'land, p. 66.

8. MOKHTAR, M. B. (1987). Manganese specification in dam waters, Ph.D. Thesis , Univ. of Q'land, p. 105-106.

•

ADDRESS CHANGE OF EDITOR 'WATER' -

ADDRESS CHANGE

This Journal has a new Editor with a new address for correspondence: E. A. Swinton, Editor, 'Water' 4 Pleasant View Cres.

Glen Waverley 3150 Phone (03) 560 9306

WATER February, 1989 37

Technical Note: The Use of Wedge Wire Screens in Wastewater Treatment D. J. BRISTOW ABSTRACT This paper discusses a specific application of a wedge-wire screen normally used in the mining industry, to the treatment of raw sewage on an island resort. The paper looks at the reason for choosing the wedge-wire screen, the problems associated with it and the solutions to problems involved.

INTRODUCTION All too often in the wastewater industry, engineers design or retrofit components using traditional equipment because of known performance and familiarity. This paper examines the application of wedge-wire screening technology normally used in the mining industry to the successful solution of a wastewater treat~nt problem.

THE PLANT The sewage,treatment plant in question treats wastewater from the Great Keppel Island holiday resort. The raw sewage is made up of wastewater from the resort's kitchens, guest houses, shower blocks and staff quarters. Raw sewage flows are of the order of 150-200 m' / day (ADWF), with peak wet weather flows of some 600 m' / day. The composition of the raw sewage is generally stronger than normal domestic sewage - Table 1.

Raw sewage is gravity fed and pumped to a central pump well from which it is lifted by two submersible centrifugal pumps to the head of the treatment plant. The plant head works consisted of a manually scraped coarse bar screen and comminutor, but the latter failed soon after commissioning in 1981-1982.

The plant proper consists of two diffused-air activated sludge systems and an oxidation ditch, two rectangular clarifiers and a tablet chlorinator for the final effluent which is discharged through an ocean outfall.

Sludge is transported around the plant by airlift pumps and waste sludge is aerobically stabilized prior to dewatering on drying beds.

were considered unsuitable or too expensive. Automatically raked screens were also considered to be ineffective and too costly and likely to add further to the routine maintenance of the plant.

It was decided to install a static sieve bend using parabolic wedge-wire screen cloth with a 3 mm aperture similar to that used in the mining industry for pulp separation. The screen was built

by Aquatec Maxcon in Brisbane and shipped to the island. Installation was completed in one day.

The screen added a further 3 m head to the pumping system.

The screened sewage was then fed to the plant under gravity flow.

It was initially thought that a large rubbish bin would be suitable for the collection of the screenings, but this proved inadequate due to the amount of solids and water from the screen.

It was anticipated the screenings would consist of food scraps in addition to rags and paper, but it was found that the screen also captured large amounts of bread crumbs, seeds and fat.

A collection tray with a draining facility was built and connected to the screen frame to hold the screenings and allow further dewatering, but the drainage system in the collection tray blinded continuously and the tray rapidly filled with water. A slight modification to this channel using silicone sealant alleviated this problem.

Disposal of the screenings was not a problem because of the short detention times in the sewer catchment. There was no odour problem when screenings were removed daily and buried.

DISCUSSION The new wedge-wire static sieve bend is now performing most satisfactorily. The incidence of blockages has,been reduced to virtually nil. The suspended solids load on the plant also appears to have been reduced by some 40-600Jo. The experience demonstrates the successful application of static wedge-wire screens in a small sewage tri!atment plant. Problems with this technology in the past appear to have been on larger plants where volumes of both removeable solids and raw sewage have been far in excess of the screen's capacity.

THE PROBLEM In May 1987 the plant operator reported severe maintenance problems due to blockages of the sludge lines and air lift pumps due to an accumulation of rags and other materials. To keep the plant operational required frequent cleaning of the sludge lines, on average two to three times a day.

ACKNOWLEDGEMENTS The author wishes to thank Australian Airlines (operators of Great Keppel Island resort) for their permission to present this paper and Aquatec Maxcon Pty Ltd for their help with the project.

TABLE 1. AVERAGE RAW SEWAGE COMPOSITION Average

Item pH Conductivity Total dissolved salts Suspended solids BOD Ammonia nitrogen Total phosphorus Sulphide Hydrogen sulphide

uS/ cm mg/ L mg/ L mg/ L mg/ L mg/ L mg/ L mg/ L

7.9 1100.

770.

400.

500 .

65.

13 .

1.7 0.3

Range

6.8 740. 460. 190 220. 13. 4. 0.1 <0.1 -

8.9 1900.

1510.

770.

1200.

98 .

23.

3.8 1.7

The existing coarse screens were unable to capture the blocking material. For this purpose finer screens were needed, but it was important to avoid further demands on the operator.

THE SOLUTION Because the rag material causing the problem was generally fairly short - typically 150-300 mm long - manually raked bar screens

Mr D. 1 Bristow is a Chemical Engineer with Simmonds & Bristow Pty Ltd, Brisbane.

38

WATER February, 1989

AWWA JOURNAL

WATER Subscription for the six issues of 1989 A$20, posted by surface mail Airmail posting can be arranged at extra cost Contact: The Editor

HAZWASTE UPDATE In all future issues of the journal it is intended to include an update on news items relevant to the management and disposal of hazardous waste. Federal Councillor Errol Samuel, acting in the role of an associate editor, will coordinate this activity and should you have any material for inclusion please do not hesitate to contact him on (02) 412 1388 or c/o Metropolitan Waste Disposal Authority, PO Box 699, Chatswood 2057, Sydney, Australia.

JOINT TASKFORCE ON INTRACTABLE WASTE A Report by Errol Samuel The March 1988 issue of Water reported on the terms of commissions of an independent Taskforce established by the Commonwealth, NSW and Victorian Governments to study and make recommendations on the management, minimizations and disposal of intractable wastes. The Phase 1 report has now been released for public information and comment. Copies of the detailed two volume preliminary report are available for $25 from either of the Taskforce's offices: Melbourne, 6th Floor, 601 Lt Collins St, Vic 3000 (PO Box 4529 Spencer St, Melbourne, Vic 3001), Phone (03) 615 4425 or Sydney, 7th Floor, 157 Liverpool St, NSW 2001 (GPO Box 2649, NSW 2001), Phone (02) 265 8967.

Survey The Taskforce found that intractable wastes have been defined as "wastes for which there are no environmentally-acceptable disposal facilities currently available in Australia". The term has been applied in general to very stable organohalogen compounds and particularly organochlorine compounds such as PCB's, dioxin etc.

Preliminary inquiries by the Taskforce to identify stable organochlorine waste quantities in Australia have revealed 9100 tonnes of stockpiled materials, 3000 tonnes of material in service, and a generation rate of 425 tonnes per year. Currently about 500 tonnes of organochlorine waste per year are being exported from Australia for disposal.

The Taskforce considered it probable that further detailed surveys would reveal significant extra quantities of organochlorines requiring destruction, particularly PCB wastes. Likely sources include capacitors and transformers in service, contaminated mineral oil in badly-flushed transformers, and contaminated soil, particularly in electrical switchyards. The actual gross tonnage of stable organochlorine wastes in Australia could be 50-100 per cent more than that already identified.

The Taskforce's terms of reference directed it to consider primarily the need for disposal facilities for intractable wastes. The possible associated disposal of non-intractable wastes was to be considered as a matter of secondary importance.

However the Taskforce found that there are many organic wastes such as paint resins, organic solvents and pesticides which are presently not being disposed of by the best available technology (BAT). In many overseas countries these wastes are co-destroyed with intractable wastes and this lead the Taskforce to conclude that ''overall hazardous waste management would be improved significantly if both intractable and non-BAT wastes were treated in an intractable waste facility". A very preliminary estimate was that about 10 000 tonnes year of non-intractable wastes were produced in south-eastern Australia.

Conclusions The Taskforce found that significant sections of the public gauge the bona fides of government and industry actions on waste management according to commitment to action on waste minimization rather than in giving priority to disposal technologies. A waste management policy based on the following hierarchy of management processes was therefore recommended: • prevention • minimization • recycling • treatment (physical, chemical, biological and incineration) • landfill.

The Taskforce recognized that much of Australia's intractable waste is currently in stockpiles which cannot be minimized or recycled out of existence. The Task force has therefore concluded that 40

WATER February, 1989

a single, central facility for the destructioo-of solid and liquid intractable and non-BAT wastes is needed in south-eastern Australia.

After examining a range of disposal options for dealing with intractable wastes the Taskforce found that there are very few processes which destroy both liquids and solids, are well-proven and widely accepted, and are suited to the particular distribution of intractable waste in Australia.

Extensive experience overseas has demonstrated that with good management, high temperature incineration results in virtually complete destruction of all organic waste. After examining all options, the Tuskforce concluded that a fixed, land-based, rotary kiln high temperature incinerator should be established in south-eastern Australia.

The proposed facility should be used to destroy and dispose of intractable wastes stored and generated in south-eastern Australia, and in other States and Territories as may subsequently be agreed.

Non-BAT wastes generated in the Australian Capital Territory, New South Wales and Victoria should also be destroyed in the proposed facility.

The Taskforce has estimated that a facility to destroy intractable and non-BAT wastes would need to have a capacity of about 12 000 tonnes per y~ar. If intractable wastes only were destroyed, the required capacity would be about 2500 tonnes per year.

Rough estimates indicate that destruction of intractable waste in a facility with a throughput of 2500 tonnes per year involving a capital investment of about $14 million and employing about 40, mainly skilled, workers would cost about $3000 per tonne.

A capacity of 12 000 tonnes per year would allow a further 9500 tonnes per year of non-BAT waste to be destroyed at an incremental cost of about $400 per tonne. The capital investment would be raised to about $25 million and the workforce to about 45.

These cost estimates assume there will not be significant infrastructure costs. If a site remote from adequate infrastructure were chosen there may be serious questions as to the project's feasibility.

The Tuskforce considered that the risks associated with high temperature incineration to be no greater than, and in many cases very much less than, those associated with other industrial plants handling hazardous materials. As a result it considered that siting criteria appropriate to other industrial facilities with similar risks would be suitable. With regard to the public consultation process the Taskforce recommended adoptioo of the Alberta Model which resulted in the successful siting of a high temperature incinerator in Alberta.

Recommendations The Tuskforce made a large number of recommendations, the more important of which are summarized below.

• Combustible organic wastes not being disposed of by best available technology be required to be directed to the intractable waste facility.

• In defining concentrations of stable organochlorine wastes which are permitted to be disposed of to landfill, including secure landfill, limits no less stringent than those applying anywhere else in the world be set. In particular, PCB-contaminated materials at 50 parts per million (ppm) or greater should not be permitted to be disposed of to landfill.

• A fixed, land-based, central, high temperature incinerator facility be established in south-eastern Australia, utilizing a rotary kiln as the primary combustion mode, together with associated facilities including a dedicated rail-based transport system, with auxiliary road-based collection, transport and transfer arrangements.

• The facilities referred to above be specified, designed and operated to exemplary standards as set out in this Report in respect of solid, liquid and gaseous emissions and residues and of occupational and community health and safety.

• The proposed facility be used for the destruction and disposal of intractable wastes stored and arising in south-eastern Australia and in other States and Territories as may be subsequently agreed.

It should also be used for the destruction and disposal of nonBAT wastes.

• Permits now issued under Commonwealth legislation for the export of intractable waste, whether for destruction in other countries, or in ships at sea, be discontinued as soon as the proposed facility is available.

• Storage of intractable waste not destined for treatment in the proposed facility or in any other approved facility (whether on-

site or off-site) operating at that time not be permitted once the proposed facility becomes available.

• Ownership, management and operating responsibilities, and funding arrangements, price structures and other financial provisions in accordance with the "polluter pays" principle.

• Well-structured, properly-researched and fully open consultation programs be developed for the carrying out of this initiative.

All necessary scientific and technical information should be made available to the public, there should be open access to all results of environmental and operational testing and monitoring, and strict timelines and undue haste should be avoided.

• A Community Monitoring Committee be established based on the community in which the facility is to be sited. The function of this Committee should be to monitor the performance of the facility to ensure compliance with all the community-related undertakings given when the facility was established.

• Siting of a high temperature incinerator in south-eastern Australia be done in accordance with the usual requirements for locating industrial plants.

• Performance specifications covering emissions and residues, operating systems and occupational health and safety, all to exemplary standards, be defined prior to the consideration of specific ·sites.

• The facility be government-owned. A separate corporate entity should be established for the purpose. The Board of Directors should be composed of members each with a significant contribution to make to the enterprise, including the supervision of health and safety; community relations; transport, operations and maintenance; financial performance and environmental monitoring.

• The operation of the facility be conducted by either a government authority, a private contractor, or the enterprises own employees, suitable qualified .

TOXIC WASTE INCINERATOR TASK FORCE PROCEEDS TO SITE SELECTION STAGE The joint Commonwealth/NSW/Victorian Government Task Force on the disposal of intractable wastes is to begin the next stage of its task in selection of a site for a high temperature incinerator.

After receiving the first report (see above) of the Task Force, Senator Graham Richardson, Federal Minister for the Environment, Mr Tim Moore, the NSW Minister for the Environment and Mr Ron Walsh, the Victorian Minister for Water Resources said "We have discussed the problems associated with the increasing volumes of stored intractable and hazardous chemical wastes and have decided the Task Force should proceed with the next phase of its work".

Considerable preliminary work was undertaken by the Labor Government in New South Wales prior to the March State election.

Mr Moore said "My predecessor, Bob Carr, whilst Minister for Planning and Environment, made significant progress on the general planning issues involved with identifying a site in New South Wales for the location of a high temperature incinerator to safely destroy this material.

"The present Government has continued that examination. There is·a bipartisan Commonwealth, State Government and Opposition agreement that a final decision must be made to resolve the destruction of this stored material", Mr Moore said.

Senator Richardson, Mr Moore and Mr Walsh said that the three Governments agreed that a high temperature incinerator should be constructed.

"We have agreed that the facility should be established in New South Wales and that the three-Government Tusk Force should now proceed with the community consultation process of identifying a suitable and environmentally acceptable site.

"This process will continue on a full public consultative basis and will seek submissions and participation from the general public and from voluntary conservation organizations". The New South Wales and Victorian conservation movements are represented on the Task Force, so there is already a significant contribution from an independent environmental perspective".

The facility will be owned and operated by the New South Wales State Government's Metropolitan Waste Disposal Authority. The Management structure will involve representation from the environment movement and the Commonwealth Government because of the national environmental importance of this facility.

VICTORIAN INDOSTRIAL WASTE RESEARCH GRANTS Four grants totalling $90 000 for research into minimizing industrial waste were awarded by the government and are to be administered by the Melbourne Board of Works.

The 1989 Grants are: • $37 440 to the CSIRO Division of Wool Technology, in conjunction with Howe and Company and the Victorian Hide and Skin Producers, for continued research into reductions in tanning effluent by implementation of the Sirolime process with liquor recycling and rapid processing technology.

This process allows hair to be recovered as a fibrous material, allowing commercialization of the hair. Because the hair is recovered relatively intact, the liquors from the process are clean and easy to recycle.

The Sirolime process also lends itself to a modified tanning technology, allowing a tannery drum to produce a load of wet-blue leather in less than 24 hours instead of the two day cycle currently required and thereby having the potential to double tanning plant capacity.

• $10 000 to Solidsep Pty Ltd for development of a mobile pretreatment plant incorporating a clarifier, rotary screens, static screens and chemical dosing equipment.

Use of the plant on-site will allow optimization of existing pretreatment processes or evaluation of new plant requirements, allow hands-on operational experience before committing funds to new or upgraded plants and permit field days or demonstrations to be conducted in regional or rural centres.

• $17 380 to Binnie and Partners Pty Ltd in conjunction with Flickers Fabrics Dyeworks, for a study of opportunities for wastewater reuse in the textile dyeworks industry. This industry uses large volumes of water for scouring, bleaching, neutralizing, rinsing and dying.

It is usual to discharge process water to waste after one use only.

Reuse of a substantial portion of the wastewater, with or without treatment, would benefit both the industry and the general community. It is proposed to study the r!-use potential at one factory, allowing identification of problems and consultation with plant operators, before applying the findings to the whole industry.

• $25 000 to the RMIT Department of Applied Chemistry and the Roberts Company (Australia) Pty Ltd, who will investigate opportunities for use of non-flammable alternatives to solvents in industry and the development of water based adhesive substitutes.

Traditional paints, inks and adhesives contain organic solvents and waste materials present environmental and disposal problems.

The project will survey industries using organic solvents to obtain a measure of the current extent of conversion and to assess the opportunities for other organic replacements.

Demonstration of project on Reductions in Tanning Effluent by CSIRO Wool Technology Division. Mr Robin Cranston of CSIRO is explaining details to guests at the Industrial Waste Grants presentation.

WATER February, 1989

41

AUSTRALIAN WATER RESEARCH ADVISORY COUNCIL

STATEMENT OF NATIONAL WATER RESEARCH PRIORITIES Introduction The following statement has been developed taking into account discussions at the 1987 National Water Research Seminar.

It is intended that this Statement will guide A WRAC and the research community towards targeting water research activity into areas of national importance.

Water research opportunities exist in a multitude of disciplinary fields, and projects are often difficult to compare from either a scientific or an applications viewpoint. Any priority ordering will be open to challenge.

Major criteria considered in setting these priorities included: . • The importance or severity of a water problem as indicated by its: effects on human health and life; - effects on the quality of life and environment; and - effects on local, regional and national economies.

• The probability that research (within the limits of time, talent, and money available) will improve knowledge and lead to the solution of problems by: - expanding the understanding of basic principles; and - identifying technological or institutional factors that might foster or hinder solutions.

• Judgment as to the cost of the proposed research in relation to possible benefits as compared to benefits that might be derived from other water research.

It is also important to note that this Statement does not take into account the extent of research currently being undertaken in the identified priority areas . However, in respect of research topics to be accorded priority for funding under the National Water Research Program, existing national research programs (e.g . those in CSIRO) and the level of national support given to these will be considered.

The Water Environment The Australian water environment has many special characteristics, including biological, physical, chemical and hydrological features which preclude the straightforward application of some research results and management techniques developed elsewhere.

An improved understanding of the water environment is required to make decisions on the future exploitation or conservation of natural, aquatic and riparian environments, particularly those containing rare or endangered biota, to decide on the extent to which modified environments should be managed to retain some natural values and to develop appropriate management strategies and guidelines. There is a need to address water use issues, particularly those which cause serious disturbance of aquatic biota, eutrophication of water bodies, or degradation of agricultural and forested lands, and to identify ways in which the quality and quantity of water harvested from catchments can be maintained and improved. The wider hydrologic and environmental issues that could arise in the event of major climatic change must be monitored for early indications of their potential impacts on the water environment.

Priority Areas for Research • Development of standardised terminology and classification systems for the measurement and description of catchment topography, land use, hydrology, hydro geology, natural environment values aned existing water resources commitments to assist in State and nation-wide water planning.

• Ecological knowledge aimed at developing sound management practices for catchments and surface waters, encompassing: - taxonomy of selected biota; - theory and models governing the structure and functioning of aquatic ecosystems, including nutrient/phytoplankton/macrophyte proceses, sediment-water processes, physical 42

WATER February, 1989

mixing processes and their effects Qil biological processes, phytoplankton-zooplankton relationships and productivity, role of abiotic and biotic processes in structuring communities, and temporal and spatial patterns and the predictability of communities; and - ecology and management of disturbed aquatic ecosystems, including the effects of catchment disturbance on aquatic ecosystems, the effects of flow regulation on aquatic and riparian ecosystems , the effects of water pollution on aquatic ecosystems and the development of water quality criteria.

• Improved understanding of catchment behaviour, with emphasis on water quality rather than quantity: - effects of land management practices (including the use of agricultural chemicals) on water quantity and quality; - effects of soil, vegetation and meteorological factors on infiltration, recharge, evapotranspirat1on and stream flow; - new methods of flow measurement in natural channels, particularly methods of high stag:e gauging; - prediction of the links between changes in land use and the subsequent emergence of dryland salinity problems, especially relating to the influence of vegetation types and climate, and the time-scale of any change; and - below-ground phase of catchment water movement, in particular, the effect of hydrogeological controls on the movement of groundwater and dissolved materials, regional scale estimation of recharge and the development of remote techniques for the evaluation of characteristics of groundwater systems.

• Improved understanding of meteorological factors affecting water resources management, encompassing: - improved estimation of magnitude and frequency of extreme rainfall and flooding, for purposes such as reservoir design and modelling of flood flows; and - assessment of the implications for the water industry of shortterm climatic variability (including drought) and long-term climatic changes.

Water Technology Issues The current drive to reduce costs in the water industry coupled with the demand for expanded and upgraded services require an increased emphasis on improving tlie performance of existing facilities, and on the development and application of appropriate new technologies . Some of these technologies may offer low cost solutions to the problems of providing small urban and rural settlements with adequate water and sewerage facilities. Many authorities will also need to undertake major programs to rehabilitate water supply and dewerage infrastructure.

Implicit in issues of water technology is the need to provide safe, good quality water supplies across the nation, and to ensure adequate consideration of public health and environmental issues arising from wastewater treatment practices.

Priority Areas for Research • Investigation of the requirements for low cost water and wastewater treatment techniques and facilities, and supply and drainage structures for small urban authorities and rural locations, ecompassing: - examination of the criteria for acceptance of a new or improved technology; - investigation of techniques currently used by major authorities which may be applicable in the small urban sector; and - methods for facilitating trialling of new approaches/ technologies .

• Development of more efficient wastewater treatment and disposal systems , encompassing: - economically viable industrial wastewater pre-treatment systems; - nutrient removal strategies; - improved understanding of lagoon treatment processes under local conditions; - on-site household effluent disposal; and - reduction of sludge bulking and methods for disposal.

• Improved water treatment techniques, especially for small water supplies:

- iron and manganese removal; - turbidity and colour removal; - control of tastes and odours, ch.lorinated organics and alternative methods for disinfection; - methods for the disposal of alum sludge; and - control of algae in reservoirs.

• Investigation of efficiency-promoting changes in irrigation practices at the farm level which have implications for water resources and their management, encompassing: - water use efficiency, including the optimisation of irrigation water use by combining intensive production on suitable soils with extensive areas of low intensity land use; - manipulation of soil physical properties and cropping systems to minimise deep percolation of drainage water; - irrigation scheduling and improvements in other inputs needed to maximise productivity; and - evaluation, testing and, if necessary, development of new irrigation techniques.

• Evaluation and development of productive irrigation and dryland land use systems under saline conditions to minimise the effect of these on water resources and their management, encompassing: - strategies for alternative uses of saline/sodic soils; and - strategies for managing irrigated land currently degraded by salinity.

• Development of improved technology for the management of ageing supply and treatment systems, encompassing: - non-destructive inspection methods and statistical modelling techniques to determine the residual life of an asset; - rehabilitation or renewal of below-ground facilities; and - selection and dissemination of information about Australian and overseas methods of rehabilitation of water supply and sewerage assets for wider adoption .

• Integration of land and water manageri,ent, encompassing: - development of a framework for assessing competing demands for catchment land use and water resources and mechanisms for resolving conflict; and - analysis of the economic, legal and organisational constraints to integrated water and land management.

• Effective incorporation of users' needs and attitudes into decision making in the water industry by evaluating: · - mechanisms for customer and community participation in decision making; - further development of management strategies to provide frameworks to co-ordinate inputs from interest groups; - investigation of community expectations and the community's knowledge of the industry; and - methods for community education.

• Investigation of the technical and economic data (including onfarm water use) required to establish a standard database for research into irrigated agriculture.

• Implications of alternative irrigation policies for farm structure, resource use and structural change, encompassing: - the design of appropriate changes in land and water use regulations, their effects on farm structures and performance; - research into irrigation farm restructuring needed to improve efficiency and identification of problems of restructuring; and - farming and general community attitudes to various farm structure and ownership patterns.

• Effects of structural changes in the irrigation industry and the development of appropriate policies, programs and legislation, encompassing: - spatial equilibrium analysis of water allocation; - effects of changes in the water and irrigated agriculture industries on the regional economy; and - development of industry, employment, and labour adjustment and welfare policies to facilitate changes.

Organizational and Institutional Issues Recently there have been significant institutional and organisational changes in the water industry. Further changes can be expected and, in the future, industry organisations will be expected to be more flexible, commercially oriented and have an improved ability to plan and forecast, and a better understanding of economic and financial issues required to make real imporvements in the management of water resources . At the same time, the role of public participation, industrial consultation and the demand for greater accountability and concern for the environment will increase.

AWWA MEMBERS WANTED

Priority Areas for Research • Development of a total systems approach to State-wide water facility planning and management for ground and surface waters, encompassing: - development and application of standard measures of risk, reliability, robustness and vulnerability of water supply systems.

• Investigation of pricing and water allocation issues, encompassing: - analysis of cost structures and integration of supply and demand analyses to establish efficient pricing for the various uses of water; - development of practical strategies for implementing marginal cost pricing while maintaining equity goals; - identification and analysis fo alternative legal structures; - development of methods for allocating water between competing (including recreational and environmental) uses , while maintaining the integrity of aquatic environments and an appropriate supply of good quality water; - development of mechanisms for transfer of water entitlements between competing uses; - integration of transferable water entitlement policies and water pricing policies; and - improved financial and economic modelling and forecasting (for large and small authorities).

WATER February, 1989 43