j 1ssN 0310 - 0357
Official Journal of the AUSTRALIAN WATER AND
W4-i •=tffii •=1 ;1;1-1--1-xeJ m•c,1~ •
I Vol. 5. No. 4, Sept. 1978 Reg istered for posting as a publication -
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HEAD OFFICE • Hoechst Australia Limited P.O. Box 4300 MELBOURNE, Vic. 3001 Tel: 510321 BRANCH OFFICES • P.O. Box 25, NUNAWADING, Vic. 3131 Te l: 8743011 • P.O. Box 126, KINGSGROVE, N.S.W. 2208 Tel : 5023555 • P.O. Box 961 M, BRISBANE Qld. 4001 Tel : 443661 • P.O. Box 137, BROOKLYN PARK, S.A. 5032 Tel: 3522655 •P.O. Box 118, PERTH , W.A. 6001 Tel : 3866311
EDITORIAL COMMITTEE Chairman: C. D. Parker Committee: G. R. Goffin G. F. Scott F. R. Bishop R. L. Cllsby Joan Powllng B. S. Sanders A.G. Longstaff W. Nicholson A. Macoun J. H. Greer B. J. Murphy P.R. Hughes J. Bales A. Wade Editor: Publisher: E. A. Swinton A.W.W.A
Official Journal of the
IAUSTRALIAN"'WATER ANDI !WASTE WATER A""SSOCIATION I
Vol. 5, No. 3 September 1978
CONTENTS Editorial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BRANCH CORRESPONDENTS CANBERRA A.C.T.: A. Macoun, P.O. Box 306, Woden, 2606. NEW SOUTH WALES: G. F. Scott, James Hardie & Coy. Pty. Ltd., P.O. Box 70, Parramatta, 2150. VICTORIA:
J. Bales, E.P.A., 240 Victoria Parade, East Melbourne 3002. · QUEENSLAND: P. R. Hughes , 46 Tucker St.. Chapel Hill, 4069 SOUTH AUSTRALIA: R. L. Cllsby, C/- E. & W. S. G.P.O. Box 1751, Adelaide, 5001 . WESTERN AUSTRALIA: B. S. Sanders, 39 Kalinda Drive, City Beach, 6015. TASMANIA:
W. Nlcholson, 101 Acton Road, Lauderdale, 7021. NORTHERN TERRITORY:
Association News . . . . . . . . . . . . . . . . . . . . . . . . . . .
Water Pollution Control in N.S.W. - Daryl T. Lacey and James E. Oliff. . . . . . . . . . . . .
The Potential for Waste Water Treatment - D.S. Mitchell . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pollution Aspects of Sanitary Landfill Leachate - H. Baumann. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pasveer Channel Design Principles - M. C. Goronszy.. . . . . . . . . . . . . . . . . . . . . . . . . .
Area and Volume Errors in Reservoir Projects - K. G. Macoun. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conference Calendar . . . . . . . . . . . . . . . . . . . . . . . . .
• INSTRUCTIONS TO AUTHORS Articles should be of orlglnal thought or reports on orlglnal work of Interest to the members of the A.W.W.A. In the range 1000 to 5000 words. Diagrams or photos would be appreciated. Full Instructions are avallable from Branch correspondents or the Editor.
A. Wade, P.O. Box 37283, Winnellie, N.T. 5789. Editorial Correspondence: E. A. Swinton, Box 310, South Melbourne, Vic. Or to Branch Correspondents. Advertising Enquiries: Mrs L. Geal,
C/· Applta, 191 Royal Par., Parkville, 3052. Phone: (03) 347-2377.
COVER STORY Pollution control does work! The famous Sydney weed which is the feed for Luderick has returned to the Parramatta River after many years. The fisherman collecting the bait had not seen the weed in this location since his youth.
"CLORETT A" ITS THE ANSWER TO YOUR CHLORINATION PROBLEM.
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Combined Instrument Systems (Australia) Pty. Ltd. 17 Thornton Crescent, Nunawading, Victoria, 3131.
Telephone: 874-7030, 874-7039, 874-6655, 874-6555 Telex: AA-31305
END VIBRATING & STATIC SCREEN Rotostrainer PROBLEMS? The Rotostrainer@ screen is a new concept applicable to total effluent and in-process waste treatment. Properly used, it cleans itself , and will not blind. Influent passes through the slowly rotating screen. Solids ride over the top and are removed by a wiper. Th e large mass of falling influent continuously backwashes screen members. The screen revolves smoothly and quietly at 10 R.P.M . It won't shake it self to pieces. And its rugged , stainless steel, all-welded constru ction req uires no tension adjustments or periodic maintenance to keep it operating,
trouble~free for months at a ti me.
TOO GOOD TO BE TRUE? THERE'S MORE ..• Th e high-capacity Rotostrainer@ screen (up to 2500 GPM) is less expensive than old-fashioned equipment to purchase, install, and operate. Its low head loss (36 inches) provides an easy fit, even in existing systems. It performs better than traditional screens. It continuously produces drier solids, 15 to 20% dry weight, down to fi nes as small as 0.010 inch. Its gentle action will not break up the solids it removes. And the Rotostrainer@ screen does all this w hile cleaning itse lf. Contact: WATER
BOBY TREATM £ MT
WILLIAM BOBY & CO. (AUSTRALIA ) PTY. LTD . 44 Koornang Road , Scoresby , Victoria , 3179 Telephone : 763 8988. Telex : 31868
Also at: Sydney 93 0311 . Brisbane 229 5800. Adela ide 278 4135
An aeration sistemis only as good asthe fineness of its bubbles * * * * * * * * * * * *
System established since 1919, with many hundreds of plants installed throughout the world. Aeration tanks flexible in design up to 9 metres depth offering maximum use of available area. Fine bubbles of 2 mm' diameter give high oxygen transfer efficiency. Un iform mixing . Simple construction in uPVC and non-co rrodible materials . Diffusers tructible.
Drainage of necessa ry .
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Automatic Dissolved Oxygen control systems available.
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'"-·"··f!j and Storage
THE PARBURY HENTY RANGE OF WATER PURIFICATION EQUIPMENT INCLUDES:
SIMONACCO DISC FILTERS The Simonacco Rotary Vacuum Disc Filter provides continuous filtration of chemical slurries, mineral concentrates , sewage sludges, etc., and can be adapted to a wide range of industrial applications. Available with discs 1.8 m diameter up to 6 discs (24 sq. m) and with discs 3.96 m diameter up to 14 discs (266 sq. m).
MANOR FILTEA PRESSES Manor Engineering Co . Ltd. equipment is supplied by Parbury Henty for sedimentation , thickening , filtration, chemical handling, pumping , elutriation, flotation , sewage and industrial effluent purification . Manor fully automated presses of the type i II ustrated have extensive uses for materials on short filtrption cycles and having good cake release characteristics.
SIEBTECHNIK CENTRIFUGES The Siebtechnik Decanter is a screenless centrifuge, in which the solids are conveyed from the large to the small diameter against the centrifugal force . The worm acts as a conveyor as well as a regulating element, and its field of application includes materials which are too fine for the screening centrifuge, provided the solids have an adequate sedimentation rate , such as flotation concentrates and waste water.
PARBURV HENTV & CO. PTY. LTD.
MINING DIVISION .
1 Lincoln Street, Lane Cove, N.S.W. 2066 Telephone 428 3533
FEDERAL SECRETARY: P. Hughes, Box A232 P.O. Sydney South, 2000. FEDERAL TREASLTRER: J . H. Greer, C/- Melbourne & M.B,.W., 625 Lt. Collins St ., Melbourne, 3000. BRANCH SECRETARIES: Canberra, A .C.T. D. Henley, P.O. Box 306, Woden, A.C.T., 2606 New South Wales: P.J . Mitchell, C/- Envirotech Australia Pty. Ltd ., P.O . Box 220, Artarmon , 2064. Victoria: R. Povey, P.O. Box 409, Werribee, 3030 . Queensland: J. Ryan, C/- Gutteridge Haskins and Davey, G.P.O . Box 668K, Brisbane 4001 . South Australia : A. Glatz, C/- Engineering & Water Supply Dept. Victoria Square , Adelaide, 5000. Western Australia: R.J . Fimmel, P.O. Box 356, West Perth, 6005. Tasmania: P.E . Spratt, Cl - Fowler, England & Newton, 132 Davey St. , Hobart, 7000 . Northern Territory: A. Wade, C/- Dept. of Construction, Mitchell St., Darwin. Thanks to N.S.W. Branch for organising contributions to this issue.
EDITORIAL A DIFFERENT CHALLENGE At the recent Annual Meeting of N.S.W. Branch, Professor J. W. Roderick, Head of the School of Civil Engineering at the University of Sydney, spoke on the future of engineers. Much of what Professor Roderick had to say is relevant to many members of this Association. With the fall-off in population growth-rate which has occurred recently in Australia, and which will continue unless influenced by changes in the present immigraHon policy, construction of new water supply and wastewater facilities will decline. Under these conditions it will be necessary for the engineering professor to develop new fields of enterprise, both technically and geographically. While the volume of work available in the traditional fields of water supply and wastewater systems will gradually decrease, increasing pressure from pollution control requirements could well produce a rapid expansion of work in this field. One problem at the moment would appear to be a lack of available expertise in the technology required for treatment of some industrial wastes. There are a number of industries in Australia which up until now have been employing rather elementary methods for treatment of their waste products. This situation will inevitably be changed, and the engineering professor must develop the expertise and equipment to meet the technological problems involved. Geographically Australia is well placed to compete with other countries for work in the Asian and Pacific areas. To obtain an increased component of the work available in this area may require the creation of large multi-disciplinary teams. These could well consist of a combination of consultants, equipm'ent manufacturers and possibly government and/or semi-government bodies. Such combinations may well be necessary to provide the depth of expertise and physical resources req ~ired to compete in the world market. It is up to the Australian engineering professor to develop the technology and organisation required to meet the changing pattern of the industry. K. A. WATERHOUSE, President, N.S.W. Branch
A.W.W.A. MEMBERSHIP Requests for Application Forms for Membership of the Association should be addressed to the appropriate Branch Secretary . Membership is In four categories : 1 . Member- qualifications suitable for membership In the Inst. of Engineers, or other suitable professional bodi es . ($12 p.a .) 2 . Associate - experience In the W. & W . W. Industry, without formal qualifi cati o ns . ($12 p. a. ) 3. Stud ent . ($5 p.a .) 4. Su staining Member- an organisation involved in the W. & W . W. Indu st ry wishing to sustain the Association . ($65 p .a.) Plu s St ate levy of $3 in N .S.W. and Vic .
ASSOCIATION NEWS NEW SOUTH WALES The incoming Committee for year ending 31/8/79 is as follows:Mr. K. Waterhouse. President; Mr. R. R. Ash, Vice President; Mr. J. K. Knight, Immediate Past President; Mr. P. Mitchell, Hon. Secretary; Mr. J. Oliff, Hon. Treasurer. Committee: Mr. H. Bandier (Reg . Conf.), Dr. D. Barnes, Mr. J. R. Eslake, Dr. T. J. Judell, Mr. G. W. Montgomerie (Programme), Mr. K. Mostyn, Mr. G. F. Scott (Correspondent), Mr. T. M. Smyth, Mr. D. M. Stevens, Mr. T. J. Twyman (Membership). Federal Councillors will be Mr. Knight and Dr. Judell. The Annual General Meeting was held on Friday, 18th August. Following the Meeting, Professor J. W. Roderick, Challis Professor of Civil Engineering, University of Sydney, addessed the members on "Future Education of Engineers". Tentative plans are well in hand for our 78/79 programme and, by the time members receive copies of this Journal, we will have held our Annual Dinner on 15th September at the Crows Nest Club. Other dates to mark in your diary are: Tuesday, 31st October - General Meeting; Thursday, 30th November - Christmas Party; 16th to 18th March, 1979 Regional Conference, Leura Everglades motel; Date to be determined - Joint meeting with The Institute of Engineers, Australia. Sustaining Members play a very important role in providing substantial funds to allow the Association to operate effectively. The N.S.W. Brach would like to thank our sustaining Âˇ members and pay tribute to them. SUSTAINING MEMBERS N.S.W. BRANCH Allied Colloids (Australia) Pty. Limited Australian Fertilizers Limited Australian Lubricating 011 Refinery Limited Australian Oil Refining Pty . Limited Council of the City of Blue Mountains Caltex Oil (Australia) Pty. Limited Coal & Allied Industries Limited Council of the City of Dubbo Environmental Studies Council - NSW Institute of Technology Envirotech Australia Pty Ltd Gatx-Fuller Australasia Pty. Ltd . Gosford Shire Council James Hardie & Co. Pty. Limited 8
The Hunter District Water Board Laporte Australia Limited Lightnin Mixers Pty. Limited The local Government Engineers' Association of NSW John Lysaght (Australia) Limited Maritime Services Board Merck Sharp & Dohme (Australia) Pty. Limited Metropolitan Waste Disposal Authority Metropolitan Water Sewerage & Drainage Board Ralph M. Parsons Co. Pty. Limited Permutit Co. of Australia Pty. Limited Department of Public Works Rankine & Hill Rous County Council Prominent & Fluid Controls Pty. Limited (Formerly Rowpel Australia) Sharples-Stokes Pty. Limited Snowy Mountains Engineering Corporation Southern Riverina County Council Staff Industries Canada Limited Division of Construction Coatings Pty. Limited State Pollution Control Commission John Thompson (Australia) Pty. Limited Total Australia Limited Tubemakers of Australia Limited Unilever Australia Pty. Limited Union Carbide (Australia) Limited Wallace & Tiernan Pty. Limited Water Resources Commission
NORTHERN TERRITORY For those that are wondering, that famous cyclone did take its toll. The old N.T. Branch failed to revive for four years. Then, like Phoenix rising from the ashes, a group of 30, mainly new faces, turned up at the first meeting of the re-formed Branch in October, 1977. Dr. Alan Wade spoke on " Darwin Water: is it for real?" Discussing the quality of the water supply, he concen trated particularly on the problems of the microscopic colonial alga, Botryococcus braunii. At the next meeting, about 50 inspected the $2 m Wastewater Treatment Plant at Fannie Bay, combining chlorination, lime treatment and aeration . They were addressed by David Hibbert and Norm Allen , and finally enjoyP.d themselves at the Yacht Club. Dr. John Quinn from the Department of Health led an evening of lively discussion on "Public Health; Myth, Magic or Reality?" In contrast to the preceeding tour of inspection, the next visit was that everpopular perennial, a tour of the N.T. Brewery. So it can be said that the re-formed Branch is alive and well , and financially bouyant. At the second A.G.M., August 1978, Ray Gruber was re-elected President. In his address, he stressed the role of AWWA in the Territory. "In an area where good professional resources are necessarily limited and widely spaced, the Association facilitates open and
intelligent communication between the various professionals and non-professionals interested i,, the water industry and in the conservation of water resources in a semi-arid zone of the continent, including the environmental effects of mining operations."
QUEENSLAND The current drought in Brisbane was the subject of the address by the retiring President, Geoff Cossins, to an Annual General Meeting of the Queensland Branch in August. Garden sprinklers have been banned in Brisbane from 1st April , 1978, he said , due to two factors - an all time low annual rainfalr over the catchment of Somerset Dam, the main reserve storage for the system, and . the inability of the recently completed North Pine Dam to deliver its quota of water to the city . The latter factor, he pointed out, depended on the staged completion of a major pumping station in the suburb of Enoggera to complete the delivery works from the North Pine source. Apart from the sprinkler ban which has reduced water consumption about twelve percent in the winter period, Geoff told his audience, the main solution to this difficult problem was to build short bypass mains to allow existing suburban pumping stations to be re-adapted to meet the crisis. These pumping stations were used to reverse the flow in existing major mains to distribute North Pine water to areas of the City previously supplied with Somerset Dam water, reducing the demand on the latter by nearly 25 per cent (double the effect of the sprinkler ban). The temporary boosting arrangement has also demonstrated increased flexi bility in operating the water supply system and has shown that all con sumers could be supplied with about half their normal water requirements from the North Pine source alone in the event of a major emergency. Following Geoff's retiring address which was well received by the sixty odd members present, Alan Pettigrew thanked Geoff for his year as Branch President, one that has further cemented the Branch into a solid based Association of members concerned with Water and Wastewater Problems. All present joined with Alan to show their appreciation of Geoff's work through the year. Program for remainder of year includes: November 1st Dinner Meeting, Majestic Hotel. Speaker, Dr. Harland Jn., Chief, Environmental Research Centre, Ada, Oklahoma who will address us on the "U .S. Scene regarding landdisposal of wastewater." November 22nd - Social Evening , Majestic Hotel, end-of-year get-together including films on watery subjects.
AWWA Eighth Convention 1st-5th October, 1979. Call for papers extended to 17th November, 1978. To be held at Chevron Hotel, Surfers Parad ise, Gold Coast. Make a ho liday of it, bring all the family, all can be arranged, see advert elsewhere in this issue. All convention correspondence to Convent ion Secretary, P.O . Box 129, BRISBANE MARKETS, 4106.
SOUTH AUSTRALIA At the Annual Genera l Meeting on 15th September, the Committee for 1978-9 was announced: Dr. C. 0. Fu ller, Pres ident; Mr. M. C. Sanders, Vice President; Mr. D. J. Lane, lmmed. Past President; Mr. A. Glatz, Secretary; Dr. J. M. Rolls, Treasurer. Committee: Messrs A. L. Clisby, P. A. Norman, K. 0 . Trevarton, A. D. Greenhough, S. A. Lewis, K. J. Shepherd. On 26th Ju ly, Dr. Dav id Lynch spoke on the policies for trade-waste discharge to the Melbourne Sewerage System . The criteria for an equitab le method of charging for both quantity and content were outlined . On 15th September, after the A.G.M. a symposium was condu_cted on _the Australian Arbo-Encepha lI tIs Monitoring Programme. Dr. D. P. Russell and Mr. M. A. Smith of the S.A. Health Commission, and Dr. R. Laughlin of 'the Waite Institute, spoke on the epidemio logy of the disease, the entomology of the vectors, and the fie ld programme for control. The disease first came to not ice in 1917, and has re-appeared at frequent but irregular intervals, main ly in the Murray Basin. In 1960, the main vector was identified as the mosquito, Cu/ex Annulirostris, the life cyc le being maintained in the natural bird li fe. The pattern of outbreak seems to fo llow large southerly migrations of bird li fe caused by rainfa ll patterns. Since it is impossible to control the birds and insects of Northern Australia, and not particularly practicab le to control the bird life of the Murray Valley, or to wipe out the mosquito population by heavy doses of insecticide, the programme has focussed on a system of mon itoring, so that the activity of infected mosquitos can be limited whenever they approach areas of population. From correlations of mosquito population with incidence of the disease, there wou ld seem to be a thresh -hold level above wh ich transmission takes place, and epidemic ensues. An earlywarn ing system has been devised, based on monitoring of the mosquito population, and checking for virus in blood samples from domestic chickens in the infested areas.
TASMANIA Fifty members and guests attended t he Branch An nual General Meet ing on the 29t h September .
Office bearers for the coming year are: J . Stephens - President . B. 0 . Healey - Vice President. E. R. England - Immediate Past President . P. Spratt - Hon. Secretary . A. J . A. Young - Hon . Treasurer . H. H. McFie, D. R. Walters, P. G. Crawford - Federal Councillors . J. F. Pottinger , J. Lawrence, W . J . McEwan , W. Nicholson , Correspondent . J. Bowen, Launceston, Northern Tasmania . In his Annual Report , Roy England highlighted three areas of Branch activity - membership (now at 73 plus 2 being processed) , the Summer School (wh ich all agreed was highly successfu l) and general meetings . Unfortunately the latter held the Branch 's low note for the year - a total lack of support for the only meeting arranged for northern members . The meeting had to be abandoned . In concluding his report , Roy stated he be lieved the year had been particularly successful and had seen the Tasmanian Branch 'come of age'. The meetiQ,g was preceded by drinks and dirv<'er, the main speaker for the evening1being the Hon . R. Groom M.P. , Minister for Env ironment , Housing and Community Development . / In his address to fhe Branch the Minister outlined major developments in the field of water resources management in the previous year, in particular the consolidation of respons ibi lity for water resources from several ministries to that of National Development, the Minister being Mr. Newman . He also referred to the National Water Resources Program wh ich has been allocated $200 million over a period of five years . The Minister continued with a review of environment protection legislation as it affects Water Resource Projects, and the growing concern in the area of hazardous chemicals and their effects on water supp lies and also accumulate in the food chain . To those who didn't attend and missed out - make a special effort next year!
WESTERN AUSTRALIA At the recent Annual General Meeting of the Branch the following committee was returned for 1978/79: Dr. Gordon Barrett-Hill - President . Mr. J . Katnic - Vice-President . Mr. R. Fimmel - Hon . Sec ./Treas . Committee - Messrs C. Tucak , N. Platell , B. Sanders , B. Robins , D. Montgomery , R. Loo . This is basically the same group who guided the Branch over the past year and while they were successful in making gains in membership , all are of view that a further large growth is essential to the success of the W .A . Branch . If W .A. is to make a success of its first Nationa l Convention in 1981 it will need the interest and support of all
relevant professions associated with the water industry in Perth . The paper at the A.G.M . was presented by Mr. Petei Clarkson, Principa l Assistant Engineer, Water Supp ly, Metropo litan Water Board, and dea lt w ith the distribut ion of water throughout. Perth . The majority of papers delivered on water tend to deal with resources, water quality and treatment and it was most interesting therefore to consider the day-to-day prob lems of storage, transport and distribution and hear of the control and operation techniques used in a large distribution system .
VICTORIA The Committee for 1978-79 was <iro elected as follows: Bill Duller - President . Bob Swinton - Vice President. Robin Povey - Secretary . Ken Wood - Treasurer. Sam Rogerson Alan Longstaff John Anderson Ian Lowther Frank Bishop Joan Paul in g Ken Chiller Eric Sorenson Wayne Drew Alan Strom Keith Levey Bob Turner Reg McMillan was co-opted as Asst . Secretary ; John Bales was co-opted as Branch Correspondent. The Federal Councillors w ill be Frank Bishop and Alan Strom . The meeting farewelled George Gollin , who has held office both at Federal and State level since the founding of the Association. After the A .G . M . , the retiring Pres ident , Mr. J. S. F. Rogerson (Deputy Chairman of the State Rivers and Water Supply Commission) delivered an address on Professional Ethics , drawing attention â&#x20AC;˘to some of the situ~tions in which contracting engineers may find themselves . Meetings throughout the year have been we ll attendad , the programme committee having Âˇorganised interesting and informative speakers, covering a wide spectrum of interest , from technical to political. At the June meeting Gordon Cou lson , of the Latrobe Vall ey Board, and Laurie Reilly , of the State Rivers Laboratory, spoke on the investigations which preceded the design of outfall sewer, which has to carry highly saline waste from the SEC power plants. In Ju ly Mr. Steve Hancock (Australian Groundwater Consultants) gave a we ll illustrated report on overseas act ivity in water and wastewater treatment by aquifer recharge. This was followed in August by Mr. Alex Manderson, First Assistant Secretary of the Water Division of the Department of National Deve lopment, who spoke on the financial implications of Water Resources of the future. The main September meeting was of course the AGM, but there was also a Cont . on Page 21 9
"WATER POLLUTION CONTROL IN NEW SOUTH WALES - RETROSPECTIVE AND PROSPECTIVE Daryl T. Lacey and James E. Oliff INTRODUCTION Protection of water resources is a significant component of the development and husbandry of the nation's resources. In N.S.W., the Clean Waters Act 1970, permitted a new approach to be made to the problem of reducing and preventing pollution in all of the waters of the State. It provides for a single authority, in lieu of the diversity of organisations that were previously empowered to deal with water pollution; it is explicit in its definitions and clear In Its intent . The first part of this paper outlines a successful pollution control programme In a highly industrialised and urbanised river basin where direct discharges of waste-waters created an intolerable level of pollution, but where alter- , natives were readily available and for the most part, cheap. The second part suggests that future problems may not be so easily resolved . One very important one Is the effect of population growth In Sydney's outer metropolitan areas. Though New South Wales is relatively free from gross manifestations of cultural eutrophlcatlon, Inadequate disposal of increasing quantities of nutrient-rich wastes poses a threat to some important rivers. Other problems are associated with shore-line disposal of sewage and estuarine pollution by sewer overflow structures. Though control of pollution by urban stormwaters from highly developed metropolitan areas may be a "lost-cause", control in areas allocated to future development will be far easier if land-use planning avoids the mistakes of the past . RETROSPECTIVE Less than six years ago many thousands of continuous and intermittent discharges existed in New South Wales particularly in the Industrialised centres of Sydney, Newcastle and Port Kembla. Since November 1972 most have been brought under control - now there are fewer than 750 discharges, all licensed under the Clean Waters Act . Ail other discharges have been dealt with by diverting them to sewerage (for treatment before disposal), by recycling them or by disposal onto land. In metropolitan estuaries such as the Georges, and Parramatta and Cooks Rivers dramatic Improvements in water quality have been achieved. The following brief description of the manner in which this was accomplished in the Parramatta River illustrates the effectiveness of the Clean Waters Act In dealing with the high loads of Industrial pollution evident for several decades past.
The Parramatta River Fig. 1 is a map of the catchment area. Above the city of Parramatta, a number of small weirs form ornamental lakes. The river flows over a larger weir into the saline tidal reach, and then some thirty kilometres through densely populated suburbs before joining the Lane Cove River and entering Sydney Harbour. Duck River Is the predominant rlghtbank tributary entering at Silverwater. It drains a catchment of 30 square kilometres of flat land to the south-west of Sydney , flowing northward Dr. Daryl Lacey is Head, and Jim Oliff is a Senior Chemist, Clean Waters Branch, State Pollution Control Commission, /NSW). This is a condensation of a paper they delivered to Environment '78, the 4th Environment Conference held in Sydn~y in June 1978.
about ten kilometres to its confluence with the main stream . The catchment of Duck River is highly developed and contains extensive residential, commercial and industrial areas . Its lower, saline reach is almost exclusively occupied by industrial sites , one of the largest being that of Sydney's first oil refinery. s tate pol lution
contro l commission_../ ·-\
'\ ..... ·~~.••':!, ~..........~~ \
\,, ,... _, ,..
The catchments of the Parramatta and Lane Cove Rivers together accommodate a population of 640,000 people, an increase of more than 40 per cent in the last twenty years and now accounting for almost one quarter of the Sydney Metropolitan total. Waterside bays and wetlands on both banks of the upstream reach, most of them unsuitable for residential development, are the nuclei of Industrial activi ties, although few industries located on the river foreshores are dependent on a waterfront l~atlon. By 1972 the sources of all direct discharges to the Parramatta River and tributary creeks had been located. Surveys had shown that of 1370 drains discharging at that time, 50 per cent flowed from industrial and privately owned premises, 42 per cent were stormwater drains and sewer overflows, and eight per cent originated in Government establishments . Of the 682 drains from industrial and private premises thirty per cent of them (210 drains) carried dry weathpr flows, either continuously or intermittently, and of those, 67 drains carried pollutants from the premises of 28 different organisations . Water quality surveys established that the most significant polluting effect in Parramatta River was low dissolved oxygen, a result of the oxygen demand in two high-volume, low strength discharges containing dissolved organic compounds and carrying oily residues, Other discharges, too, were highly polluting. They were low volume, high strength wastes with a high oxygen demand, or were highly toxic, or both, discharged from many Ind ustrlal pram lses . The waste streams included ; • coal tar oils , vegetable and animal fats • acids and alkalis • salts of chromium and other heavy metals • chlorinated hydrocarbon residues • organic and inorganic sulphides and sulphur compounds • phenol and phenolic compounds
• putrescible garbage dump leachates • abattoir wastes including animal faecal matter • accidental discharges resulting in gross local pollution notably spills of caustic soda, ethyl alcohol , vegetable oils and petroleum oils . Since pollution was manifested primarily by the depletion of dissolved oxygen, the restoration of sufficient dissolved oxygen to sustain estuarine fish populations was recognised as the most practical objective for the programme of pollution control . Only discharges which met the criteria of low volume, low oxygen demand, low concentration of solids in suspension and of being visually free of oil were permitted. Other wastes were diverted to the sewer , so that all other contaminants, especially toxic materials, were eliminated. The co-operation of Sydney's sewerage authority, the Metropolitan Water Sewerage and Drainage Board, in accepting the increased load of industrial wastes, made this implementation of point source control effective from the outset. Improvements in water quality in Parramatta River and In Duck River, illustrated by surface concentrations (0.5 metre) of dissolved oxygen, are shown in Figure 2 which is derived from a statistical analysis of all measurements· made by the State Pollution Control Commission, since August 1971. The figures are derived from pooled data from river sectors, each comprising several sampling stations where dissolved oxygen measurements during each period totalled 50 to 150 individual measurements. There is, therefore, a substantial basis for the following conclusions : • In 1975, in the upper reaches of Parramatta River (including Duck River) the mean concentrations of dissolved. oxygen reached 100 per cent of saturation, minimum values in earlier years were around 50 per cent, minimum values often being as low as zero . • Removal of oxygen stress in the upper reaches Is reflected in greater stability in the downstream reaches, where the variation between maxima and minima
~ i l ~
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DISSOLVED OXYGEN IO· S METRES I
PARRAMATTA RIV ER , DUCK RIVER
FI G Z
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STATE POLLUTION CONTROL CO MM ISSION
" ,.,~ ·",.,,
SALI NITY (AT 0.5 METRES) PARA AMATTA RIV ER -
~ has diminished and is no more than would be expected
under "natural" conditions . The data show that the effect of eliminating dry weather sources of pollution became obvious in 1975, and that the mean values are now well within the range of water quality objectives. However , the lower ranges of the data reflect the influence of wet weather, which may be demonstrated from other data obtained during three full years, to the end of 1976. Figures 3, 4 and 5 illustrate changes in salinity, dissolved oxygen and faecal coliform counts, under wet weather and dry weather conditions. Though in most cases the range of the data is wide, the mean values give a good Indication or the changes occurring. The low range of the data obtained under dry weather conditions demonstrates that the effect of wet weather is measurable for prolonged periods after rainfall has ceased. The high range of the data obtained under wet weather conditions demonstrates that surface run-off depends not only on the amount of rai n, but also on other factors such as the intensity of the rain , the dryness of the soil, and the extent of the rainfall. Whilst the effect of rainfall is highly variable it is now the most important factor affecting water quality in the Parramatta River . The improvement in water quality achieved since 1971 is obvious to the eye - dry weather pollution has been virtually eliminated and aquatic life has returned to many areas which five years ago could support only the hardiest of species . Damaged stands of mangroves are regenerating and fringing growths of bright green seaweeds have replaced unsightly oil-stained foreshores .
POLLUTION CO NT ROL CO MM ISSION
SY DNEY HARBOUR 1974,1976 FIG . 3
STATE POLLUTION CO NTROL COMM ISS ION
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STATE POLLU TION CO NTROL CO M MISSION
PROSPECTIVE Populatlon growth In outer metropolitan areas
Recent revisions of population growth by the NSW Planning and Environment Commission (1976) indicate that by 2000 A .O. Sydney, including outer Sydney , will have
FAECAL COLIFORM COU NTS
PARRA.M ATTA RtYER -
HA RBOU R 197' -1 976
a population between 3.9 and 4.8 million , somewhat lower than previous forecasts. A large component of this increase wi ll be accommodated in the outer fringe in satellite cities (Campbelltown, Camden and Appin) west and south of Sydney. Present residential/ industrial areas around Penrith and Windsor wil l also be expanded . Population estimates for the western and south western "corridors" , radiating from Sydney are shown in Table 1.
TABLE 1 Populatlon Predictions 1980 1971 1975 Sydney and outer (millions) Thousands Campbell town Appin-Menangle Total to Georges River Thousands Camden Penrith-Windsor Total to Nepean River
45.1 2 47
93 2 95
188 12 200
224 54 278
12 88 100
16 104 120
52 139 191
97 208 305
One of the major problems of the future will be the effect that this urban expansion will have in the upper reaches of the Nepean / Hawkesbury and Georges Rivers, which In dry weather are poorly flushed. Existing sewage treatment works will be augmented, but their effluents will carry high loads of nutrients into the receiving waters. (A full discussion appears in a separate publication by the State Poll ution Control Commission (1977) ). For example , stream flow in the Nepean River is influenced only by fresh water inflows, which have been modified since the early 1900's by the construction of impoundments the largest is Warragamba Dam which was completed In 1960. Extremes of flow are common, caused by both flood rains and extended periods of dry weather . The frequency of low
TABLE i Nepean River at WaUacla Estimated effluent dllutlons for various populatlon Increments Flow kits Distribution• % Estimated dllutlons: Population 10 Increment 25 (thousands) 50 75 100
650 250 130 86 63
330 130 65 43 32
11 4.2 2.1 1.4 1.0
5 2.2 1.1 0.7 0.6
42 21 14 10
TABLE.3 Nepean River at F·enrlth Estimated effluent dllutlons for various populatlon Increments Flow kl/s Distribution* % Estimated dllutlons: popu lation 50 100 Increment 200 (thousands)
1.1 0.5 0.3
33 16 13 11
• Percentage of time that flow is equal to or less than the quoted flow.
stream-flow, and the correspondingly low volumes available for dilution and transport of effluents, is of major importance in assessing the effect of population growth in the catchment. Flow records for the Nepean River at'Wallacia compiled during the period 1917-1971, together with estimated di lutions for growing popu lations at Camden, forty kilometres upstream , are summarised in Table 2 and sim ilar data for Penrith, in Table 3. These estimates foreshadow the likelihood of serious pollution during dry weather conditions, in the HawkesburyNepean system. When the population of Camden reaches 100,000 persons dilutions of only 1:1 or less wi ll be avai lab le in the Nepean River at the point of discharge of treated effluents, during about 40 per cent of the time, but only during about 20 per cent of the time will ample dilutions of 30:1 or more be available . In the reach downstream of Penrith to the confluence of the Grose River (i.e . for a distance of some 20 K ilometres) when the combined population of Camden, Penrith and Windsor is around 200,000, dilutions o about 5:1 or less can be expected during about 30 per cent of the time during a further 20 per cent of the time dilutions will be 16:1 or less and will be more ample during only half of the time. The effects on water quality are predictable; dissolved oxygen deficits from both carbonaceous and nitrogenous oxygen demands will occur, and large growths of macrophytes and algae will be nourished by the phosphatic and nitrogenous constituents of conventionally treated sewage. The onset of stress conditions can be predicted to occur when the equivalent population load on Camden treatment works exceeds 10,000 persons and when the equ ivalent load on Penrith grows to about 100,000 persons. Even then dilutions of only 1 :1 will be available during 10 per cent of the time . To avoid these otherwise inevitable impacts on water quality, nutrient removal processes may need to be incorporated in the sewage treatment plants serving both Camden and Penrith, prior to the onset of stress conditions i.e. in the early years of population growth. Estimates of the costs of doing so (based on current values) indicate that capital and operating expenditure additional to that required for conventional treatment would be about ~20 mil lion and $2 million p.a. respectively. Downstream of Windsor the situation is not so obvious; detailed investigations are currently being carried out by the Commission . However, if the population served by the existing sewage treatment work! at St. Mary's, Quakers Hill and Riverstone grows, nutrient removal facilities will be required at those works as well, involving additional capital and incurring operating expenditure on a scale similar to that quoted above . Since stormwater enters the Nepean and Hawkesbury rapidly during even moderate rainfall, the dilution of storm run-off by the normal river flow is negligible, particularly in the upper reaches . Since urban development will Increase run-off rates, gross deterioration in water quality, principally by the transport of large amounts of suspended sediments is predictable. Time is on the side of the planners however, who have an opportunity now to ensure the reservation of river foreshore land which must be an essential component of land-use planning . Otherwise the Hawkesbury and Nepean in wet weather will exhibit the same ugly characteristics of other metropolitan rivers.
Coastal Outfall Sewers The location of Sydney on the shores of the Tasman Sea is indeed fortunate for many reasons, not the least of which is the availability of deep, well-flushed ocean waters for the disposal of sewage (fron, over two and a quarter million residents) and the very large volumes of industrial wastewaters from manufacturing and process industries. The Metropolitan Water Sewerage and Drainage Board has developed a composite network of sewers including
thirteen draining to inland treatment plants and seven systems draining to coastal outfalls . The main systems in the latter category are Bondi, Northern Suburbs , Southern and Western Suburbs and Cronulla , three minor systems are located at Diamond Bay, Vaucluse and Warriewood . The South Coast, also an area of M :W .S. and D.B. res ponsibili ty, is served by four ocean outfall systems which drain to treatment plants at Bellambi, Port Kembla, Shell harbou r and Wollongong. To the north , at Newcastle, the provision of water and sewerage is the responsibility of the Hunter Distr ict Water Board. Four ocean outfall systems drain most of the city and metropolitan area. Partially treated sewage is discharged into the surf zone at Burwood Beach (th e largest outfall) and Stockton; raw sewage is discharged in to the surf zone at Be lmont Beach, and chlorinated raw sewage is discharged at the rocky foreshore at Swansea Heads. Surfing beaches are a singular great attraction on the coastline north and south of Sydney, but the enjoyment of beachside faci li ties can be marred by the intrusion of sewage plumes from the larger coastal outfalls, even though their effect on the beaches is seldom significant. Although the Commission is v~y much in favour of ocean ou tfalls for the disposa l of wastewaters it is not satisfied that shore-line outfalls are adequate . In 1975 the Commission published its requirements for the disposal of wastes to ocean waters (1 975). The criteria specify first that wastes must be treated to remove f loating matter; secondly, that source-control must ensure that the concentrations of specified substances are not exceeded at the boundary of the initial dilution zone, and finally, that the density of faecal coliform bacteria in any part of the waters of nearby beaches must not exceed certain limits. The criteria thus provide for adequate protection of the local env iron ment and facilitate the des ign of major submar ine outfalls and diffusers . · The M .W.S. and D.B. has undertaken extensive engineering , hydrological and ecological studies off the New South Wales coastline which has established the feasibility of construct ing submarine outfal ls via diffusers located sufficiently clear of the coastline to ensure that sewage discharges do not interfere with the amenity value of adjacent surfing beaches . Overflows from Sewerage Systems
Stormwater in f il trates sewerage through illegal connections and inadequate service lines and joints, being particularly prevalent in older systems. The flow of storm water in sewer mains can great ly exceed average dry weather flows so that even generous sizing of sewer mains cannot cope with large surcharges - overflows of raw sewage, though diluted, inevitably result . Though overflows occur mainly during wet-weather conditions when recreat ional use of the receiving waters is limited, this is not sufficient reason to overlook their overall contribution to pollutant loads, especially in estuarine areas. Overflows also occur fol lowing localised storms whether in adjacent or far distant areas - Cooks River for example is subjected to overflows as a result of local thunderstorms in the western suburbs . Such overflows are. not diluted by large in -stream volumes, the usual accompaniment of rainfall in a whole catchment, and as a result, they subject the receiving waters to slug loads of high-strength oxygendemanding wastes, the effects of which can be measured over severa l days. Since detail ed information on the costs and benef its of reducing poll ut ion from sewer overflows is lacking, the Commission, in co ll aboration with major sewerage authorities in New South Wales, is carrying out a thorough investigation in order to establish : • th e effectiveness of exist ing legislative powers to reduce infiltration , and the costs of more extensive policing • the capability of overflow structures to meet specific standards in the Regulations under the Clean Waters Act
• the use of techniques (particularly those for the prediction of high hydraulic loads at spec ific points ), to reduce both the frequency and the sever ity of overflows. Control of Nutrient-rich Wastes
Of all the problems facing pollution-control authorities, none are more vexing than the specification of rat ional standards for effluents containing the common plant nutrients , phosphorus and nitrogen. The Clean Waters Act specifies that, regardless of the classification of the receiving waters , wastes are not to be discharged if they cause ''abnormal or excessive growth of plants". Fortunately there are no areas of eutrophied waters in New South Wales comparable with those frequently reported upon overseas. Apart from localised areas in the east-coast estuaries, nuisance blooms of algae are man ifested more in large freshwater impoundmdnts . Even there the problems are associated as much with widespread and diffuse sources as they are with point sources. A study by the_ Commiss ion in Burrinjuck Dam (1978) provides detailed information on the manifestation of blooms in a large impoundment; it is hard to decide whether inflows from the city of Canberra and several large towns are more of a prob lem than Inflows from widespread pastoral and agricultural activities on the catchment. However the Commission's attitude on the future disposal of nutrient-bearing wastes whatever their source is that: • it is unacceptable to argue that the discharge of nutrientbearing eff luents to a waterway should be permitted for the reason that the waters are In any case subject to urban and agricultural run-off which may promote excessive plant growth • judicious location of treatment fac ilities, particularly the outfal l, can overcome potential problems • it is far better to use ocean outfalls, where practicable, than to discharge effluents to sensitive , poorly flushed estuarine areas • land -disposal is an excellent means of nutrient removal and is encouraged • if chemical remova l is contemplated, phosphorus is probably the more important nutrient to remove. However, the removal of nitrogen (by nitrification and denitrification) in intermittent processes (such as in the Pasveer channel) may be a feasible alternafive and such processes are encouraged. Pollution by Urban Run-off
Since point sources of pollution have been controlled the effects of pollution from diffuse sources have become more obvious. In highly developed catchments urban run-off is now the major source of pollution and its future control is a monumental task for all control authorities. It is now well established that, during the first several hours especially, run -off from urban areas carries with it a variety of pol lutants , including oxygen demanding wastes , organic and inorganic silt, nitrogen and phosphorus compounds, animal faecal matter, oils , heavy metals and litter . An investigation was made by the Commiss ion in June 1975 in a small catchment draining to Tarban Creek, an arm of the Parramatta River near Hunter's Hi ll. This basin (with an area of about 85 hectares ) was chosen as being typical of thick ly populated residential areas. The results showed that substantial quantities of contaminants were discharged during storm cond it ions. In an eight-hour period , almost 50 kilograms of organic oxygendemanding matter were discharged, equiva lent to the daily d ischarge of domestic sewage from about 2500 persons. The load of suspended solids was 400 kilograms with an average concentration of 250 milligrams per litre. The quantities of nitrogen and phosphorus were equ ivalent , respective ly, to 30 kilogram of sulp hate of am monia and 30 kilograms of superphosphate. This, and overseas results, highlight the fact that the magnitude and duration of the initial "slug" load of pollut-
• ants is of primary importance when considering the way in , which pollution from storm run-off may be controlled. Met hods proposed for control are many and varied . There are '- those which recommend the replacement of conventional surfaces on secondary roads, footpaths and gutters with pervious surfaces; others advocate an "urban planning ': approach where streets, gutters and nature strips are sympathetically graded, grassed and vegetated to slow down the flow of rain water and allow it to have maximum access to ground waters. Still others propose collecting run-off by diverting it to foreshore ponds, dams and artificial lakes where various forms of treatment may be given prior to a controlled release to creeks and rivers. Each proposal has merits, but in highly developed areas, where publicly owned riverside land is almost non-existent, the problems are almost insuperable. It is mainly in areas as yet undeveloped that suitably planned schemes have the best chance of implementation. It is the Commission's view that whatever treatment is proposed it should be effective in controlling short-term peak loads particularly of biochemical oxygen demand and suspended matter. CONCLUSION The Commission's influence in water pollution control in New South Wales owes much to the recognition that the elements of the whole environment are interdependent, and that environmental and social objectives though they may not always be compatible with more materialistic objectives must be given proper weight. That this approach has been effective may be demonstrated in several ways . First, and most apparent in the improved visual appearance of several waterways in highly urbanised
Obituary - MICHAEL JOHN FLYNN 1916-1978 The sudden death on 12 August of Dr. Michael Flynn has deprived both the Association and a much wider community, of a person whose outstanding services to his country and fellow man were sustained throughout a too brief lifetime of sixty two years. A Foundation Member of the Association, Michael was elected Federal President and New South Wales Branch President in 1963 and 1964. He occupied these offices again in 1967 and 1968. The Association's inaugural Fed· eral Conference in 1963 was evolved from a planned meeting in Canberra of the New South Wales Branch and Michael Flynn was the driving force behind this first federal conference. He was a member of Federal Council continuously from 1963 until 1976 wher he retired in accordance with rules r ; the incorporated Association and ~e was elected an Honarary Life Member of the Association. He retired from the New South Wales Branch Com, mittee in 1977. Closely connected with the Association's activities was Michael's role in the International Association on Water Pollution Research . He became Honorary Secretary-Treasurer of the Australian National Committee of 1.A.W.P.R. in 1973 and as Treasurer of the Eighth I.A.W.P.R. Conference Organising Committee during the years 1974 to 1976 he was eminently successful in secur14
catchments; secondly in the acceptance by industry and government bodies of their responsibilities; and finally in the acceptance by the community of the objectives of the Government implemented through the Col'hmission . Experience gained in the short time that water pollution control has been effective confirms that in many instances water pollution problems are a concomitant of short-sighted use of land areas. Future siting of residential or industrial areas must take full cognisance of the need for protecting waterways from the impact of land developments. Planning for the collection, treatment and disposal of land wastes is an essential corollary . A significant part of the State Pol lution Control Commission's role in water pollution control has been and will continue to be the development of policies , practices and guidelines aimed at achieving appropriate water quality objectives and the highest practicable level of pollution abatement . ACKNOWLE DGMENTS The authors thank Mr. E. J . Coffey, Director of the State Pollution Control Commission for permission to publish this paper. We have quoted liberally from several reports, the work of colleagues who have made significant (though anonymous) contributions to publications of the Commission. Their work is acknowledged with gratitude. REFERENCES N.S.W, Planning and Environ ment Commission, "Population Projections for New South Wales, 1975-2000", Technical Bulletin 8, 1976, State Pollution Control Commission (NSW), " The quality of Sydney 's natural waterways In re/at/on to Its growth", 1977, · State Pollution Control Commission (NSW), " Design criteria for ocean discharge", Environmental design guide WP-1, 1975, State Pollution Control Commission (NSW), "A water quality survey of Burrln/uck Reservoir and the Upper Murrumbidgee River - August 1973 to August 1975", 1978,
ing financial support from governments and industry which assured the success of that conference. Michael continued to serve the National Committee of I.A.W.P.R. as Secretary and as a member of the Melbourne Specialised 1978 Conference Organising Committee until his death. Michael's contributions to the Association were as fruitful as they were continuous and colleagues on committees or councils were always assured of the active and forceful participation which stemmed from his keen intelligence and mental vigour. Michael Flynn commenced his professional career as a cadet engineer in the Sydney Water Board but this engineering career was interrupted by World War II and in 1940 he enlisted in the 7th Division of the A.I.F. Whilst a prisoner of war in Malaya, his interest in a medical career developed. On his discharge from the Army he was married in St. Mary's Cathedral Sydney on 1 February 1946 to May Donnelly. Some indication of the support and strength given by May throughout his life is shown by the fact that Michael commenced his medical course at the University of Sydney in February 1946. Following graduation Dr. Flynn started his medical career as a general practitioner but soon specialised in chest diseases with the Joint Coal Board until December 1963 when he rejoined the Sydney Water Board as its Chief Medical Officer. He occupied this position until 1972 when he was appointed technical adviser to the Board on pollution control. Besides his medical degree he held
a Masters Degree in Science and a Diploma in Public Health. He was a Fellow of the American Public Health Association, the Royal Society of Health and the American Co llege of Chest Physicians. He was awarded a National Health and Medical Research Council Travelling Fellowship in 1960 and in 1962 he was Chairman of the World Health Organisation's 13th Congress in Manila. He was a consultant to the South East Asian Treaty Organisation on Cholera Research from 1962 to 1966. He held a p6sition as Assistant Director of Army Health with the rank of Colonel from 1961 to 1965 and he was author of a Parliamentary White Paper on Fluoridation in 1963. He was President of the Royal Society of Health from 1966 to 1968 and Vice President of the Anti T.B. Association from 1969. An organisation to which he gave devoted service was· the St. John's Ambulance Association of New South Wales of which he was chairman in 1976 and 1977. He was admitted to the order of St John in 1964 and elevated to Knighthood in 1977. We in the Association owe a debt to him for many jobs well done and for the numerous facets of his character always directed towards worthwhile achievements, based upon a strong religious conviction and demanding much affection from his many friends. Michael Flynn was a man who could not resist a challenge nor refuse a request for help. Our deepest sympathies are extended to his wife May and family.
THE POTENTI_ AL FOR WASTEWATER TREATMENT BY AQUATIC PLANTS IN AUSTRALIA D. S. Mitchell INTRODUCTION
Current awareness of the long-term danger of damage to the environment and of the diminishing levels of many natural resources has focused attention on alternative methods of processing wastewaters so as to decrease adverse environmental impacts and promote re-use of water and the production of useful by-products (Gutteridge, Haskins & Davey, 1977). Among these methods is the use of aquatic macrophytes (mostly vascular hydrophytes as opposed to algae) in tertiary and even secondary treatment of domestic sewage and industrial wastewaters. Th~ concept of using plants in the treatment of wastewaters is not new. Algal growths, which oxygenate water and "strip" nutrients from it have long been realised to be valuable components of various forms of settling and evaporating ponds. Aquatic macrophytes were suggested as a means of removing excess nutrients from eutrophic waters several years ago. Âˇ It is now known that aquatic macrophytes - possess several desirable features which enhance their potential for use in the treatment of waste-waters, Scirpus lacustris, an emergent plant, is capable of metabolising complex organic substances, such as phenols, and of producing exudates which were toxic to bacteria. Various species of aquatic plants are capable of concentrating heavy metals from wastewaters and evidence that many aquatic plants routinely absorb more nutrients than they require from nutrient-rich waters (luxury uptake) Is accumulating . Natural swamp communities are capable of handling wastewaters so as to reduce nutrients and sediment load in both fresh water and estuarine conditions. However, their capacity to do so depends on the species of plants present. For example widespread stands of sawgrass (Cladium jamaicense) in the Florida Everglades were rapidly saturated with phosphorus and were adversely affected by continuous additions of surplus nutrients. Artificial systems, in which fast growing water weeds are used, probably offer more Dr. David Mitchell was brought up in Rhodesia, and has worked on problems with man-made lakes and water weeds in Africa. He edited a UNESCO publication on " Aquatic Vegetation, its use and control" in 1974. He came to Australia in 1977 to join the CS/RO Division of Irrigation Research, Griffith, NSW.
promise. Recently, considerable attention has been paid to water hyacinth (Eichhornia crassipes) in this regard. Utilization of aquatic plant material harvested from both natural and artificial systems has also been actively investigated, particular attention being paid to weed species (Boyd, 1974; National Academy of Sciences, 1976). A major problem is the removal of the water, which constitutes 85-95% of most aquatic plants, but processes have been developed which overcome this. Five main forms of use have been examined: the production of protein , either direct or after feeding to fish, the production of fibre which can be used for various purposes including paper manufacture, the production of stock feeds, composts, and methane. The last of these provides a viable method of disposal for plants which have accumulated large quantities of heavy metals and would therefore be unsafe to recycle. Australia is characterised by highly vari able supplies of surface waters. Over many areas of the continent, water is the limiting factor to plant and animal life and therefore to primary production. At the same time, the cont inuing population growth in coastal areas causes concentrations of wastes which provide disposal problems and also creates demands for resources, including water, which will become increasingly difficult to satisfy. The development of systems which will make it possible, at low cost, to recycle water, minimise pollution from waste, and provide a source of useful by-products in both these situations obviously requires urgent study. The investigations and research findings referred to in the preceding paragraphs clearly indicate that treatment of wastewaters by aquatic plants can meet these objectives. The factors that need to be examined in order to initiate this approach in Australia will be reviewed in this paper.
ments listed in the following graphs.
1. Rapid growth Many floating aquatic weeds exhibit very high rates of growth in conditions where space is available for colonisation and abundant nutrients are present over a period when temperatures and light values are high. For example, water hyacinth doubles every 6.2 days in sewage oxidation ponds in Florida and salvinia (Salvinia molesta) has been reported to double every 36 hours in nutrient-rich conditions at Mount Isa, Queensland . Submerged and emergent plants which are usually rooted in the substrate, are less spectacu lar but doubling times of 12 days have been reported for hornwort (Ceratophyllum demersum) and in a single growing season, one seed of Typha latifolia (Typha spp are commonly called cumqungi in Australia) produced a network of rhizomes occupying an area with a diameter of about 3 m in which there were 98 aerial shoots and 104 lateral buds. It is important to reali se that plant growth in non-limiting conditions is generally exponent ial so that, if growth is recorded in terms of regular biomass increments during a particular period, there will be an early "lag" phase when increments are relatively 'small even though the doubling time may be con stant. Thus the plants would have to be harvested in such a way as to maintain a reasonably high bll omass in the sys-
CRITERIA FOR TREATMENT SYSTEMS EMPLOYING AQUATIC PLANTS
Conventional primary and secondary treatment methods are capable of producing clear, odourless water with acceptable oxygen level s but disinfection and some form of expensive tertiary treatment is required to remove nutrients and eliminate disease bearing organisms . Any systems employing aquatic macrophytes would have to meet the same criteria. In addition , the plants that would warrant selection for investigation would have to satisfy the require-
Tall Spike Rush (Eleocharis Space/a ta).
tern at all times. For management of the system, it would also be necessary to know the nature of the growth curve, under different conditions, for the species of plants that are present. 2. Easy propagation Many aquatic plants can be propagated readily from a piece of vegetative tissue containing a growing point. Some of these plants are incapable of sexual reproduction (eg salvinia) or have spread extensively without ever sett ing seed (eg Canadian pondweed: Elodea canadensis). Other plants, such as cumbungi, produce vast quantities of viable seeds. Water hyacinth is characterised by ready and frequent vegetative reproduction as well as the production of seeds, which provide a means of survival through an adverse season. Several other plants produce resistant vegetative prcipagules, such as tubers, which provide an alternative mechanism of survival. However, the factors which break the dormancy of such propagules are not known for most aquatic plants and , thus they do not provide a means of propagation in managed situations. 3. Relatively constant growth Many aquatic macrophytes exh ibit a seasonal growth pattern characterised by periods of rapid growth and periods of slow growth. The latter provide a serious obstacle to the use of these plants for wastewater treatment in areas where the climate is markedly seasonal while the production of wastewater is not. Plants of tropical origin, which are predominantely vegetative in growth, such as water hyacinth, are, however, capable of sustained growth, providing temperatures are maintained at high levels. It is possible that other species, which do not respond to chan ges in daylength, would behave similarly, but this requires investigation. 4. High capacity for the absorption of nutrients and other "waste" substances
The environmental factor most likely to limit the growth of aquatic plants during the growing season is the availabi lity of nutrients. Many of these plants appear to have compensated for this by developing a capacity to absorb large quantities of such nutrients over and above their immediate requirements during periods when these are readily available. This characteristic provides one of the main bases for employing such plants to " strip" nutrients from wastewaters. However, unless the nutrients are ultimately utilised in growth or removed by harvesting the plants, a proportion of them will be returned to the system, either through leaching or following death and decay of the plants. The latter consequence can be avoided by regular harvesting but more work is required to estab li sh the nature and frequency of the former phenomenon. 16
For predictive purposes and to promote effecti ve timing of plant harvests, it will be important to establish the relationsh ip between the concentration of nutrients jn Âˇthe water and in the plant. A number of studi es have been made of the mineral composition of aquatic vascu lar plants in various fresh waters but, generally, the concentration of minerals in the plant are not compared with ambient concentrations of the same minerals in the water, or show no correlation with them. Nevertheless, a general relat ionship appears to exist. In nutrient-poor conditions,
Canadian Pondweed (Elodea canadensis). \
plants respond principally to limiting nutrients by increase in growth rather than by increase in nutrient concentrations in their tissues. When nutrients become non-limiting, luxury uptake may occur and tissue concentrations increase with no increase in growth. Above a certain ambient concentration, plant tissue concentrations increase no further and may even decline owing to poor plant health. More work is required to establ ish the nature and quantitative basis of this phenomenon for different plant species, bearing in mind that the response will be affected by the proportions of different macronutrients present in the growth medium in relation to the plants specific requirements for these nutrients. For example. McNabb & Tierney (1972) showed that there is a li near increase in the phosphorus content of hornwort with increasing concentration of soluble phosphorus in the water up to levels of 3 mg 1Âˇ1. Simi lar responses were to be found in other submerged species. However, the response to inorganic nitrogen was different, there being no increase in tissue concentration with increase in ambient concentrations up to 14 mg 1Âˇ1. Musil & Breen (1977) used growth kinetics to calculate the quantities of water hyacinth that would be required initially, the quantities to be harvested, and the frequency of harvesting, in order to remove specified amounts of nutrients from a system under different temperature regimes. The abi lity of many aquatic plants to concentrate heavy metals and to metabo li se certain organic pollutants without adverse affect to themselves is clearly of considerable significance to their use as a means of treating industrial wastewaters. Wolverton et al. (1976) postulated that 0.4 ha of water
hyacinth has the potential to remove 68 kg of phenol every 72 hours and 120 g of heavy meta~. such as cadmium, lead and mercury, every 24 hours. Alligator weed (Alternanthera philoxeroides) was less proficient in removing heavy metals. The possibility of using aquatic plants to concentrate precious metals, such as gold, is also being investigated (National Academy of Sciences, 1976). An important aspect of the nutrient relationships of prospective aquatic plants is the site of nutrient absorption . Boyd (1967) demonstrated that many rooted emergent species absorb nutrient from the sediment rather than from the water. For examp le, cumbungi obtains its phosR_horus primarily from the sediment (Caines, 1965). Clearly, such plants are less suitable for nutrient absorption from effluent than those species which absorb nutrient mainly from the water, such as hornwort (McNabb et al., 1970). However this factor could be disregarded if it cou ld be shown that nutrients were absorbed by a whole system, such as a natural swamp, and bound in sediments without detriment to the swamp itself, or to anyone using its waters.
5. Tolerance of hyper-eutrophlc conditions Physio-chem ical conditions change through any . wastewater treatment system. If aquatic plants are to be used, it will be necessary to establish the limits of tolerance of these plants for different concentrations of oxygen, organic matter, nutrients and turbidity. This would make it possible to locate different species in those parts of the system. most favourable to them to ensure the ir maximum effectiveness.
6. Easily hervested and preferably useful For a system employing aquatic plants to be effective, it will be necessary to maintain the growth of the plants at high levels throughout the year. This will entail regular harvesting without damaging the potential of the plants to continue to function in the system. Emergent species, such a"s cumbungi and the common reed (Phragmites australis), may initially appear attractive in this regard as they are morphologically similar to many crop plants for which effective mechanical harvesters are avai lable. However, care has to be taken not to damage the rhizomes which are the basis for plant regrowth and most mechanical harvesters could not penetrate far into swamp systems. Free-floating aquatic plants are the easiest to harvest without damaging the plants potential for immediate regrowth and do not require specialised machinery, although various quite complex devices have been developed (Livermore & Wunderlich , 1969; Nicholas, 1974). Submerged spec ies
provide more problems but these can be minimised by designing the system to accommodate the harvesting device. Suitable machinery is available (Robson, 1974; Nichols, 1974), but caref,ul consideration has to be given to the stage of growth of the species concerned . Various uses for harvested material have been investigated, as mentioned earlier, and National Academy of Sciences (1976) provides a recent comprehensive guide to the information available. In Australia, it will be desirable to concentrate on those uses which make minimum demands on expensive labour inputs. The basis of production of useful material by the plants is the substances that are initially formed during the process of photosynthesis. This is conventionally expressed as dry matter production in terms of t ha·1 year1, or g m·2 day· 1. Aquatic plants are capable of some of the highest yields known . For example, cumbungi (emergent) can have a yield of 52 g m·2 day· 1 (compared with a 26 g m· 2 day·1 for sugar cane in Indonesia) (Westlake, 1963), water hyacinth (free-floating), a yield of 24 g m·2 day·1 (Wolverton et al., 1976), and hornwort (submerged) a yield of about 10 g m·2 day· 1 (McNabb & Tierney, 1972).
Much of the recent work that has been carried out to explore the potential use of aquatic plants for the treatment of wastewaters in other parts of the world has concentrated on weed species, such as water hyacinth and alligator weed , which are declared noxious weeds throughout Australia. It would clearly be irresponsible (and illegal) to cultivate these plants under conditions from which they could escape to areas where they do not occur, or from which they have been eradicated. For this reason, investigations in Australia should concentrate on the native species which exhibit rapid growth rates and are tolerant of wide ranges of environmental conditions. These characteristics are often revealed by a plant's capacity to be a nuisance in man-managed systems, such as irrigation canals and drains. J . S. Weir (at University of New England) has been investigating a number of emergent species, such as cumbungi, common reed and tall spikerush (Eleocharis sphacelata), and has shown that the latter has a particularly high phosphorus uptake under natural conditions. More work is required to establish its maximum levels of uptake under hyper-eutrophic conditions.
POSSIBLE TYPES OF SYSTEMS The design of a suitable system will have to take account of the growth form of the plants concerned and of a desirable retention time for water in the system, in relation to the plant's capacity for nutrient absorption. For example, water should be shallow when floating plants are employed and ensure good light penetration for submerged species. Most of the systems that have been tried consist of large open ponds or interconnected channels. • Different systems could be used in series to take advantage of the sequential change in physic-chemical conditions mentioned earlier. Different systems would also be appropriate to different effluents, say from a piggery or feed-lot in comparison with domestic or industrial wastewater. A major problem with the latter is the space that may be required in areas where the economic value of land is high. Fairly complex systems are now being designed and investigated. These will promote the recycling of useful material and the safe disposal of waste. Consideration is also being given to designing systems to accommodate planteating fish or for feeding harvested material to fish, such as white amur (Ctenopharyngedon idella) (Sutton, 1978).
In Australia consideration should be given to using existing swamp systems to filter run-off and effluents before these enter water bodies which are liable to eutrophication. For this reason the present tendency to reclaim swamp areas for agricultural use should be reconsidered. Swamp systems are valuable components of the Australian ecosystem and should not be destroyed, without a full understanding of the long-term consequences. Where swamps do not exist, it may be possible to create conditions which would promote their development by constructing small weirs in suitable flat areas at the headwaters of impoundments or below effluent discharge points. The possibility that these may increase water loss through evapotranspiration is probably slight as Linacre et al. (1970) have shown that swamp systems in semi-arid areas of Australia lose less water than open water surfaces.
APPLICATION TO AUSTRALIA Certain studies and concepts are particularly relevant to Australian condi tions.
Another aspect of the use of aq uatic plants for the treatment of wastewaters in Australia which requires investigation is the relationship between such systems and human disease organisms. Native plants should be evaluated to establish whether they have the same capacity as Scirpus litoralis to exude antibacterial agents. The passage and survival of bacteria and viruses through the systems will have to be established and methods of management worked out that will minimise the breeding of mosquitoes, and other vectors of
human diseases, in proximity to human habitation. Possible methods o~ harvesting and potential uses for harvested material also have to be studied. No attempt has been made to develop methods of utilising aquatic plants in Australia, although there are significant quantities present, potentially suitable uses exist, and large sums are spent on their chenical control, where they are considered a nuisance (Mitchell, 1977). Unfortunately work in all these areas is being inhibited by lack of funding will continue to be slow while this situation persists. Furthermore, conditions in Australia are sufficently different to make it impossible to utilise overseas research findings directly and research is needed to modify and adapt them to our situation and requirements.
REFERENCES Boyd, C. E. 1967. Some aspects of aquatic plant ecology. Reservoir Fish. Resource Symp., April 5-7, 1967, Athens, Georgia. p. 114-129. Am . Fish . Soc., Washington, D.C. Boyd, C. E. 1974. Utilisation of aquatic plants. In : D. S. Mitchell (ed .) Aquatic vegetation and Its use and control. p. 107-115. Unesco, Paris. Caines, L. A. 1965. The phosphorus content of some aquatic macrophytes with special reference to seasonal fluctuations and applications of phosphate fertilizers . Hydroblologla, 25:289-301 . Gutteridge Haskins and Davey Pty Ltd . 1977. Planning for the use of sewage. Aust . Govt . Publ. Serv. Canberra. Linacre, E. T., Hicks, B. B., Sainty, G. A. & Grause, G. 1970. The evaporation from a swamp. Agrlc. Meteorol. 7:375-386. Livermore, D. F. & Wunderlich, W. E. 1969. Mechanical removal of organic production from waterways. In: Eutroph/catlon: causes, consequences, correctives. p. 49;4-519. Nat. Acad. Sci., Washington, D.C. McNabb, C. D. & Tierney, D. P. 1972. Growth and mineral accumulation of submerged vascular hydrophytes in pleloeutrophic environs. Inst. Wat. Res. Mich. State Univ., Tech. Rep. 26. East • Lansing . McNabb, C. D., Tierney, D. P. & Kosek, s. A. 1970. The uptake of phosphorus by Ceratophyllum demersum from wastewater. Report of project A-031 -Mich, Inst. Wat. Res. Mich . State Univ. (Mimeo.) Mitchell, D. S. 1977 Aquatic weeds in Australian inland waters . Aust. Govt. Publ. Serv . Canberra. Musil, C. F. & Breen, C. M. 1977. The application of growth kinetics to the control of Eichhorn/a crassipes (Mart.) Solms through nutrient removal by mechanical harvesting . Hydrobiologia 53:165171 . National Academy of Sciences. 1976. Making aquatic weeds useful: some perspectives for developing countries. National Academy of Sciences, Washington , D.C. Nichols, S. A. 1974. Mechanical and habitat manipu· lation for aquatic plant management. Tech . Bill. 77. Dept, Nat. Res., Madison, Wisc. Robson, T. 0 . 1974. Mechanical control. In: D. S. Mitchell (ed.) Aquatic vegetation and its use and control. p. 72-84. Unesco, Paris. Sutton, D. L. 1978. Utilization of wastewater with aquatic macrophytes and the white amur. Final report to Fla Dept. Nat. Res. ARC Fort Lauderdale Research Report FL-78-4. Westlake, D. F. 1963. Comparisons of plant productivity. Biol. Rev. 38:385-425. Wolverton, B. C., Barlow R. M . & McDonald, R. C. 1976. Application of vascular aquatic plants for pollution removal, eoergy and food production in a biological system. In: Tourbier, J . & Pierson , A. W. (eds.) Biological control of water pollution. Univ. of Pennsylvania Press, Philadelphia.
POLLUTION ASPECTS OF SANITARY LANDFILL .LEACHATE H. Baumann* INTRODUCTION The volumes and characteristics of leachate vary widely from one garbage depot to another, and depend on such factors as: • design of landfill site • hydrogeology of site • operation technique • topography of site • climate (rainfall) • season • age of disposal site • depth of refuse • nature of garbage. The aims of the study described in this paper were: (i) to evaluate the characteristics of leachate draining from putrescible waste depots within the Sydney Metropolitan Region, as shown in Fig. 1. (ii) to examine the extent of water pollution caused by the discharge of leachate into surface waters. (iii) to evaluate the degree to which adequate planning , design and operation of garbage depots can minimise the potential for water pollution by leachate.
THE SURVEY The survey was undertaken following a period of wet weather in order that leachate production would tend to be at a maximum . The rainfall for the twenty-four hours immediately prior to the survey of the individual tips varied from 0.4 to 68.8 millimetres. However rainfall for the two week period immediately preceding the total survey period was 262 millimetres which is very high when compared with the long term average of 100 millimetres for the corresponding four week period. At each depot the site was then examined for signs of leachate production and, if evident, its flow was determined at the point of discharge from the site or, if inconvenient, at some suitable intermediate point on the site. Samples of the leachate were taken at the point of flow measurement. Analyses carried out on the collected samples included pH, chemical and biochemical oxygen demand, ammonia nitrogen, total phosphorus and electrical conductivity. The samples were also analysed for concentrations of iron, zinc, copper, lead, cadmium and chromium.
* Herbert Baumann is a Senior Chem-
ist, Clean Waters Branch, State Pollution Control Commission, NSW. 18
All testing was carried out in accordance with methods published in " Standard Methods for the Examination of Water and Wastewater, 13th Edition" . All samples collected for metal analyses were acidified on site with HNO, to a pH below 1. Iron and zinc were determined by direct atomic absorption spectroscopy, while all other metals were preconcentrated by extraction prior to analyses. FIGURE 1. Map of Putrescrible Garbage Depot Localities
RESULTS The flowrates of leachate discharged from most of the sites are given in Table 1 together with the results of the analyses for pH, COD, BOD, ammonia nitrogen, phosphorus and conductivity. The results of the analyses for meta!s are given in Table 2. During 1977 about one third of the depots ceased operation, with gradual reduction of the leachate. Tables 1 and 2 do not contain the results of the surveys at the · Menai depot (Sutherland Shire) or the Belrose depot (Warringah Shire). These two depots produce large volumes of effluent; at Belrose _a treatment plant exists and at Menai a plant will soon be constructed. For these reasons these two operations are discussed separately. DISCUSSION The wide variation in the concentration of the listed characteristics is related to the amount of dilution the leachate received by natural seepage and run-off. For example, the BOD ranged from 3 to 5,000 mg/I, and the
NH,-N concentration from 0.3 to 595 mg/I . Generally, high concentrations of organic pollutants, expressed as BOD, are associated with high levels of ammonia-nitrogen and total iron. The latter is responsible for visually unpleasant brown deposits and staining at the leachate discharge points. The magnitude of the pollution is expressed more reali stically by the hourly organic loading of the leachate discharge. Low or negligible organic loadings were associated with satisfactory site selection and management of a garbage depot or the small scale of the waste disposal operation . At the time of the survey, the organic load varied from 0.05 to 5(), kgBOD5 per hour; individual discharges from three depots amounted to a loading of above 20 kg BOD5 per hour. Values below 1 kg BOD5 per hour or no visual discharge were found at twelve depots. The concentration of total iron in leachate is highly variable. With some of the depots, such as Ryde and Holroyd, the effect of the dilution by stormwater is readily identifiable. However, with depots such as Sydney Brick Pit, Bankstown, Canterbury and Kogarah, high leachate flows are associated with high concentrations of iron, brought about by the scouring effect of stormwater flows. Except for two depots, the concentrations of the non-ferrous metals were quite low. Howe.,er, the discharge from the Canterbury depot is notable for its high concentrations of heavy metals, since, at the time of the survey, it was being used for the disposal of industrial metal finishing waste. The high concentration of lead in the leachate from the Sydney Brick Pit may come from old industrial wastes. The results of water quality surveys carried out during 1975 indicate that the leachate which discharged directly or via tributaries to the Hawkesbury, Georges and Parramatta Rivers had little effect on the quality of these waterways. Average values for BOD and ammonia-nitrogen at the points at which leachate enters the river were 2-6 and 0.03-0.36 mg/I respectively. An increase in ammonia-nitrogen con-· centration in the Lane Cove River cannot be attributed solely to leachate discharge, as significant amounts of nirtogen enter the river as a result of periodic sewer overflows during heavy .rain and to some extent from the many septic tank installations in the area). It is apparent that the dilution provided in all these waterways is suffi-
LEACHATE FROM SYDNEY GARB AGE DEPOTS (Apart from Menal and Belrose)
TA BL E 1: VOLU METR IC FLOWRAT ES AND ANA LYT ICAL RESULTS Sample Origi n Ma p Ref.
Date of Collect ion
CO D mg/I
Flow k lfhour
Campbell town Campbe ll town Holroyd Bankstown Canterb ury Hurstville Hurstville Kogarah Liverpool
5 5 8 9 11 12 12 13 6
L E E E L L E E
5.2.76 5.2.76 4.2.76 27.1.76 27.1.76 27.1.76 27.1.76 27.1.76
7.0 6.7 7.5 6.5 7.6 6.6 7.2 7.1
357 108 11 .9
0.25 0.58 0.08 0.69 4.30 3.86 0.13 0. 55
2,500 2,900 1,000 1,650 > 12,000 20,000 1.305 1,450
280 7,370 6,630 112 112
1,500 40 9 9 4,500 4,400 45 20
167 11 2.9 120 58
Rockdale Sydney B.P.
Auburn St rathfield
515· 350 ·
16 18 17 7
Ryde Lane Cove
57.5 39 1
2, 400 5,690
0. 41 0.20
Windsor Black town
595 266 11 .2 40.7
FIGURE 2. Menai Garbage Depot Row Leachate .• .. _ ... o,.,..._i......
No Discharge No Dis charg e
Prospect Cr. Pro spect Cr.
2 were both 62 milligrams per litre, ranging from 2 to 1,300 milligrams per litre. Visible effects:.were iron stained rocks, bed slime growths and massive growths of brown and green algae.
ORGAN IC LOAO.
FLOW, kllolilt•• /doy
TABL E 2: CONCENTRATIONS OF METALS Sa mple Origin Ma p Ref.
Date o f
Zi nc ma/I
Lead m ol l
Chromium ma/I 1975
W in dsor Blacktown
Campbe lltown Holroyd
5 8 9
L E E L L E
5.2.76 4.2.76 27.1.76 27.1.76 27.1 .76 27.1.76
0.08 0.05 1.4 18 1.3 0.58
2.6 35 59 9.1 27
0.01 0.02 0.68 0.07 0.03
0.022 0.02 0.005 0.22 0.02 0.017
0.001 0.001 0.001 0.03 0.002 0.002
0.006 0.005 0.014 0.005 0.005 0.01 3
Bankstown Canterburyt Hurstville Kogarah
12 13 6
Rockdale Sydney B.P.
Auburn Strathfield Parramatta Falrfield
16 18 17 7
Ryde Lane Cove
1.8 11 .2
Horns by Ku-rlng-gai
28.1 .76 28.1.76
Prospec t Cr.
No Di scharge
No Discharg e
0.01 0.Q1 0.Q1
Remarks L "" Depot discharge, leachate seepage only . E "" Depot discharge, a mixture of leachate and stormwater run -off . • "" Tidal, flow es timat ed on the outgoing tide. Prospec t Creek UIS and D/S "" creek wat.er quality up strea m and down stream of the adjacent garbage depots of Holroy d an d Fairfiel d Co un cil s.
Depot recei ving metal finishing liquid waste, and high metal concent rations ref lect the c harac ter of thi s waste (practice now d iscontinued).
ci ent to prevent any significant changes in average water quality. However, th e immediate effects of leachate loads on these waters, such as locali sed oxygen defici ts, zones in which ammoni a concentrat ions may be above des irable limits, and undesirable staining in th e proximity of th e leachate disch arge points are ju st a few of t he undes irab le aspects which may need to be investig ated further.
MENAI GAR BAGE DEPOT A compreh ensive survey was carr ied ou t at t his garbage depot over a six month period and is still continuing. Results obtained so far indicate that the · organic cont ent of the leachate peaks approxi mately one month after t he maximum observed rainfall, and is
roughly proportional to th e total month ly rainfall for the area, as shown in Figure 2. Five samplin g stat ions were operated on a small t ributary of Mi ll Creek, whi ch later feeds to t he Georges River, as shown in Figure 3. A summary of th e detail ed data is given in Tab le 3., toget her wi t h rainfa ll statist ics in Tab le 4. More detail ed res ult s for stat ions 1 and 2 indicate th at the quality of the tri butary was signif icant ly affected for the greater proportion of the survey period . Reasonab le water quality was only fou nd during periods of extremely high rainfa ll wh en the ef flu ent was adequate ly dilu ted by natural run-off, and for prolonged dry weath er condit ion wh en no leachate was d ischarged from t he depot holding ponds. Flow-weighted mean values for BOD, at station 1 and
The water quality of Mill Creek itself is significantly affected after its confluence with its tributary. At station 3 (Mill Creek upstream of leachate affected tributary) the flow-weighted mean values of BOD,, NH,-N and iron concentrations were 2, 0.08 and 0.6 milligrams per litre, respectively. However, at Station 4 (Mill Creek - downstream of leachate affected tributary) these same respective parameters were 14, 17.6 and 2.3 milligrams per litre. At Station 5, located approximately 1.5 kilometres downstream from Station 4 and immediatt!ly upstream of the weir, the water quality of Mill Creek improved slightly with flow-weighted mean values of BOD,, NH,-N and iron of 8, 9.8 and 1.9 milligrams per litre respectively. At all stations, with the exception of station 1, the concentrations of zinc, copper, lead, cadmium and chromium were less than 1.4, 0.01, 0.04, 0.002 and 0.007 mg/I, respectively. At station 1, the maximum concentrations of these metals, were 1.3, 0.04, 0.085, 0.006 and 0.025 mg/I. It is doubtful whether these concentrations of metals would have any harmful effect on the aquatic ecosystem. Bacteriological tests carried out on samples collected at each station indicate a considerable die-off of faeca l coliforms over the surveyed length of the watercourse. At station 1, for instance, faecal coliform organisms ranged from 470 to 21,000 per 100 millilitres wh ilst at station 5 a range of 4 to 40 organisms per 100 mi llil itres was recorded. Based on maximum numbers of organisms determined, these figures represent a 99.8 per cent die-off. 19
TABLE 3 MILL CREEK SURVEY, 22 S6PTEMBER 1975 TO 17 MARCH 1976 Min , Max, Means (flow-weighted)
7 1410 415
20 4120 1236
26 5540 1569
131 7860 2448
3 884 + 234 +
Diss. Oxygen mg/Litre
7.0 Nil 3.6
7.3 2.6 4.7
9.0 4.0 7.3
7.5 3.4 6.1·
6.3 2.2 4.6
2340 72 192
1260 20 235
45 1 27
400 16 57
21 0 16 69
1300 5 62
680 2 62
2 2 2
260 1 14
54 1 8
298 12 34
93 4.3 53
0.2 0.01 0.08
61 1.6 17.6
26 0.9 9.8
Total Phosphorus mg/Litre
0.47 0.07 0.17
0.25 0.04 0.16
0.07 0.01 0.03
0.09 0.01 0.05
0.07 0.03 0.03
22.4 1.9 4.7
9.4 1.4 7.6
1.4 0.3 0.6
5.5 0.6 2.3
2.4 0.6 1.9
Electr. Co nductiv. mi crosiemen/cm
4100 545 920
1960 265 1290
350 160 216
930 210 471
660 190 529
+ On the 23 January 1976 an extremely high fl ow of 7,900 kilolitres per day was measured at Station 1, as a result of a three day rainfall of 130 millimetres. This value was not included in th e tabl e. TABLE 4
MONTHLY RAINFALL, mm.
Daily Max . Monthly Tot. L.T.M.T.A.t t L.T.M.T.A.
11 .5 34 .4 54
46.0 101 .2 61
21.6 46.4 101
3.6 15.2 122
67.2 258.9 11 2
EXTENT OF POLL'UTION AS A FUNCTION OF LOCATION AND OPERATION
Long term monthl y average
BELROSE GARBAGE DEPOT At present, this is the only waste disposal site in New South Wales where leachate is first treated for the removal of iron and then disposed of by spray irrigation onto grassed areas of the landfill site. The treatment plant is designed for a hydraulic loading of 164 kilolitres per day (6.8 kilolitres per hour) and commenced operation in May 1973. Lime is used to adjust pH whilst aeration is employed in order to oxidise and precipitate the bulk of the iron compounds which are removed as ferr ic hydroxide in a clarifier. At the commencement of plant operation, the clarified effluent was sprayed over four-hectare areas of natural bushland in Davidson Park. This practice was abandoned after approximately one year of operation because of excessive run -off, and dying of the natural vegetation. Since November 1974, a more successful disposal method was employed in which treated leachate was sprayed onto a grassed area of the completed landfill operation . To this date, no adverse effect has been observed on the grass being irrigated. A
on the water quality of Bare Creek at a station 1 km downstream of leachate entry. The quality of untreated and treated leachate was also determined. The extent of contamination is a function of the amount of leachate overflowing from the collection dam and the degree of dilution provided by the flow of creek water. Table 5 summarises BOD and ammonia values at the station together with creek flow , pollutant loads, and the time since the cessation of leachate discharge to the creek. The worst degree of pollution occurred on the 22.1.75 when all leachate from the site, including storage dam contents, was discharged to the creek. It appears that a minimum period of four days is required to return the BOD to normal. A much longer period of time is required for the ammonia-nitrogen concentration to decrease to a level that might be expected in a creek draining an urban bushland area. The effect of the discharge of leachate on the water quality of the lower reaches of Bare Creek and Middle Harbour Creek was investigated by consultants on behalf of the Warringah Shire Council on 12.11.73. Results of this survey are listed in Table 6. The data indicate that during the survey leachate was only an insigni ficant source of faecal bacteriological contamination of the creek and that other sources, such as septic tank seepage in the French's Creek area, play a more significant role. However, the discharge of leachate had a significant effect on the biochemical oxygen demand of the upper reaches of the creek.
slight browning of the grass has been noticed during the winter months, but this is probably due to the retarded growth in co lder weather. Lush growth of grass occurs during the warmer periods of the year.
The major aim of the survey was to determine wh!t factors may be important in planning the construction and operation of a putrescible garbage depot consistent with minimising the production of leachate.
BARE CREEK WATER QUALITY A
Last Day of Dam Overflow
Date of Survey
4.11 .75 4.11 .75 4.11 .75 14. 1.75 22. 1.76 2. 2.76 16. 2.76 15. 3.76
13.11 .75 1.12.75 15.12.75 15. 1.76 22. 1.76 3. 2.76 20. 2.76 23. 3.76
9 26 40 1
1 4 8
Condition In Creek NH,,N, mg/I
393 79 20 327
3 4 9 360 170 850 2 19 "
1.2 0.3 0.2 118 3,400 734 2.2 25
864 1,080 1,300
NH i· N, kg/day
7.4 25.1 0.3 87 12.8 59 2.6 16
2.9 2.0 0.006 28.4 256 51 2.8 21
• Small amount of leachate continu ously discharged to c reek .
The leachate disposal scheme appears to operate satisfactorily except for the overflow of untreated leachate from the collection and holding dams following periods of medium to heavy rain, particularly when a stormwater by-pass channel is primed . During the period 13.11 .75 to 23.3.76 eight surveys were carried out to determine the effect of leachate overflow
RESULTS OF BARE CREEK-MIDDLE HARBOUR CREEK POLLUTION SURVEY, 12.11.1973 BOO,
To lal .•lron
Sample Orlg_l" - - - + - -'"" -'-' _ _m_ol_l-+-o_,o_••_Jlooo _ Bate Ck , u/1 ot 0.pol
Ba,e Ck., o/s ol Oepo1 Bare Ck •. Jur'ICUon w ith M IOdte
Harbour Ck. Middle Harbour Ck above Ba,e Ck. F,encl'l'sCk Middle Harbour Ck , tielow French's Ck Middle Harbour Ck . above Rocky Ck Mlddlll HatboUI, Warr lngah Ad
3,000 8,000 10,000 10,000 800
The precise relationship between the magnitude of each leachate problem and the location and mode of operation of each tip is difficult because rainfall markedly affects the quantities of pollutants discharged, and site operation, stormwater drainage, effectiveness of clay sealing etc. vary from one depot to another. Because the results were obtained at each site during the same period and, therefore, the same weather conditions, it is possible to gain some understanding of the way by which site location alone might affect the magnitude of the problem . The types of site have been loosely classified as follows:(i) Flat sites - sites at which a sanitary landfill technique is used either by use of excavated cells or by layering and covering with soil and clay. (ii) Valley sites - sites at which the garbage is simply tipped into a valley which, ultimate ly, is filled . (iii) Reclaimed Sites (adjacent to waters) - swampy areas, often directly adjacent to waterways, which ultimately are reclaimed to yield playing fields, etc. (iv) Abandoned Brlckplts or Quarries - these can be described as 'enclosed valleys ' from which there can be no natural escape of stormwater to surface waters. TABLE 7 BOD DISCHARGE AS FUNCTION OF SITE TYPE BOD Discharged Kg/h r
Windsor Black town
Kogarah Liverpool Lane Cove Holroyd
10.5 2.34 12.8 3.0
Campbelltown Hornsby Hurstv ill e Ku -ri ng-gai Ryde (now co nn ec t ed to sewe r) Menai
0. 11 5.0 Average
Reclaimed Bank stown Canterbury Strathfield Auburn
5.6 1.5 49.5 1.44 20.6
Table 7 summarises the hourly discharges at the time of the survey from each of these classifications. Although there is great variation within each category some general comments can be made. (i) There is no doubt that a flat site employing sanitary landfill techniques yields by far the smallest quantity of pollutants.
(ii) The totally enclosed site, the abandoned brickpit, yields the largest quantity of pollutants. (iii) Reclaimed sites adjacent to waterways yield large quantities of pollutants. It is probable that tidal movement increases the quantity of leachate as a result of the periodic dissolution of organic matter during high tide. By corollary, however, the large dilution offered probably minimises the resultant effect on the receiving waters. SUMMARY AND CONCLUSIONS An examination has been made of the volumes and characteristics of leachate draining from 23 garbage depots in the Sydney region. The measurements were carried out following a period of wet weather. In addition a more detailed investigation was carried out into the characteristics and effects of leachate discharged from two large sites at Menai and Belrose. As a result of thi s study the following conclusions have been drawn. (i) As was anticipated, the volume of leachate discharged varied considerably from one site to another and was influenced by the location and mode of operation of the depot. Because leachate inevitably contains some diluting stormwater, this variability in flow influenced the strength and characteristics of th e wastes. (ii) The biochemical oxygen demand ranged from 3 milligrams per litre where flows were high to 5,000 milligrams per litre where the degree of stormwater infiltration was minimal. Concentrations of ammonia nitrogen and heavy metals (apart from iron) varied accordingly. (iii) Iron concentrations tended to increase with increasing flows at some depots, possibly indicating the scouring effect of stormwater within the body of the tip itself. (iv) There was a significant effect of leachate on water quality in areas draining to small creeks. In these cases (such as Mill Creek and Bare Creek) the water quality was affected for some kilometres downstream from the landfill sites. Natural assimilation within these creeks as 'we ll as a significant degree of dilution in downstream receiving waters is apparently adequate to ensure that there is little effect on the main stem of the parent waterway. Again, while depots located directly adjacent to major estuaries yield large polluting loads, the effect on the adjacent waters is minimised, because of the diffused nature of the discharge and its dilution.
(v) Flat sites employing sanitary landfill techniques produce the smallest quantity of pollutants. The potential for s'Ttes located in valleys to cause significant localised water pollution problems is high probably because in most cases the valley is drained by watercourses having little assimilative capacity. It is emphasised that no account has been taken in this study of the degree to which problems discussed above can be alleviated through suitable treatment or by discharge to the sanitary sewerage system. While, for instance, it was apparent that brick pit sites yield large quantities of pollutants, discharge of that leachate to the sewerage system woul obviously abate any potential water pollution problem. ACKNOWLEDGMENTS The author gratefully acknowledges the approval of the Director of the New South Wales State Pollution Control Commission to present the material contained in this paper. The Commission has acknowledged its thanks to the Metropolitan Waste Disposal Authority for the use of effluent quality data relating to the Menai garbage depot. The assistance provided by Warringah Shire Council and the use of its results concerning the Belrose tip operations are also gratefully acknowledged.
Association News, Cont. joint meeting with the Inst itution of Engineers, to hear Dr. W .S. Butcher, of the National Science Foundation, USA, talk on the administration of Water Resources in America. The October function is the weekend confere'nce to bp held in Shepparton, with the theme of. water for agriculture, and in November, a team from the CSIRO Division of Chemical Technology will describe the "Sirofloc" process, in which activated magnetite is used as an adsorbent for co lour , and as a nuc leus for coagulation. All-in-all, a very full programme .
LETTER TO THE EDITOR Re: Spring-loaded Pressure Relief Valves Mr. G. Horsnell of the Neypric Division of Alsthom Atlantique has commented (Vol. 4 No. 3) on the modifications made by HEC to their Neypric valves. Although HEC continues to purchase and use these valves. not only for penstocks but also rising mains, we repeat that In some circumstances modifications are necessary, and we are preparing a paper describing testing , modifications and experience. H. H. McFle, Hydro Electric Commission of Tasmania
PASVEER CHANNEL DESIGN PRINCIPLES M. C. Goronszy INTRODUCTION Since its development in 1954 by Pasveer at the Netherlands Institute for Public Health Engineering, TNO , the oxidation channel has found widespread acceptance as a simple and economical means of wastewater treatment . In New South Wales, the Pasveer Channel has been developed by the N.S.W. Department of Public Works as a single-tank treatment process with no separate primary or secondary settling facility other than a sludge lagoon and often a maturation pond. All the unit processes of primary settlement, biological oxidation , secondary settlement and sludge digestion, as well as nitrification and denitrification, are carried out in the one reactor. This is accomplished by automatic adjustable timing controls which cause the channel to be operated alternately as an aerator and as a settling tank. Continuous activated sludge systems with separate secondary settlement zones are usually restricted to a maximum throughput of four times average dry-weather flow. Installation of larger settlement zones leads to instability in normal operation, since anaerobic conditions can be generated , giving rise to " rising sludge" and poor effluent quality. The intermittently operated Pasveer channel is capable of a very high level of treatment, since it offers a simple solution to wide variations in organic and hydraulic loading, including most storm flows. This paper summarises the design principles for such plants, based on the concept of food/microorganism ratio, which experience has shown is best maintained at about 0.04 for extended -aeration processes in order to produce sludge of good settling and compaction quality .
THE NSW PASVEER SYSTEM In the system developed by the N.S.W. Department of Public Works, operation is intermittent, and is automatically controlled by cam timers. Normal operation allows for 4 Â˝ hours oxygenation, 1 hour settling, Â˝ hour decantation after which the cycle is repeated. Other cycle combinations may be used depending on oxygenation requirements and hydraulic loading. The reactor for 1000-2000 e.p. is trapezoidal in section, with maximum depth of 1.5 metres, and is ring shaped Mervyn Goronszy was a chemical engineer with the P. W.D. He is now a Senior Engineer, Clean Waters Branch, State Pollution Control Commission, NSW.
in plan. Other geometries are in use for larger units. Oxygenation is accomplished by horizontally-mounted floating aerators, of the caged rotor type, with adjustable immersion. On completion of the oxygenation cycle, the rotors are reversed for 30-45 seconds to check the flow, then sett ling continues for an hour. A bell mouth weir t~en descends slowly over Â˝ hour, removing clear effluent to within 0.2 m of the settled sludge blanket . A proportion of sludge is pumped continuously from the operating channel into a waste sludge lagoon, with displaced supernatant liquor being returned to the channel . The process also provides for a special "storm-flow cycle" to accommodate peak flows, which is activated automatically by a high level switch. The oxygenation cycle is reduced to 50 minutes, settlement to 20 minutes, and decantation remains at 30 minutes. ORGANIC LOADING Micro-organ isms can cont in uousiy remove organic matter from liquid wastes by only one method, synthesis into new protoplasm and its associated energy requirements. It is possible for the micro-organisms to adsorb large quantities of organic matter onto their cell surfaces; but, unless this adsorbed organic matter is assimi lated into protoplasm, the rate of adsorption will approach zero. Energy and synthesis are coup led reactions which cannot be separated. The maximum rate of energy expend iture occurs during maximum rate of synthesis. If synthesis shou ld sudden ly cease, the demand for energy would drop to a minimum. This means that since the organic matter in waste waters supplies both the energy and the building blocks for protoplasm, the maximum rate of removal of organic matter per unit of micro-organisms occurs during maximum growth . The lowest rate of removal of organic matter per unit of micro-organisms occurs after all growth has ceased. When aeration is started (Figure 1), the food /mi cro-organism ratio is very large, i.e.: there is an excess of food. Initial growth follows a log rate. During the log growth rate, the organic matter in the wastes is removed at its maximum rate with optimum conversion of organic matter into new cells. The energy level is sufficient ly high to keep all the micro-organisms completely dispersed. It is impo'$slble to get an activated sludge to form while the micro-organisms remain in ;
the log phase, although new cells are synthesised. The rapid rate of bacteria metabolism creates a very high oxygen demand. If aerobic conditions are not maintained by proper oxygen transfer, the rate of metabolism will not follow a log rate but rather an arithmetical rate until oxygen is no longer the limiting factor. The protozoa will be The food/micro-organism (F:M) ratio drops rapidly as the food is consumed and new cells are produced. A point is reached where the food is no longer in excess but is the limiting factor in future growth (AT/AB; Figure 1 ). The growth phases have passed from the log growth to the declining growth. Further growth is directly proportional to the food remaining but then both the bacteria and protozoa begin to decline (Figure 2). In the turbulent aeration tank the bacteria are constantly being brought into contact with each other. As long as the bacteria have sufficient energy, the bacteria quickly split apart and continue their normal metabolic function, but when the energy content of the system decreases, more and more bacteria lack the energy to overcome the forces of attraction between two cells once they have collided. The two cells move as a unit and soon become three and then four and so on until a small floe particle has formed. The food concentration continues to drop and the micro-ofganisms continue to increase, but at an ever-diminishing rate. The minimum F:M ratio is approached at the end of the declining growth phasef and the start of the endogenous phase. The F:M ratio continues to be reduced, but at a lower rate. It can be said t hat the system is essentially stab le in the endogenous phase . Only a small quantity of food remains unmetabolised, further metabo li sation continuing at a very slow rate. The demand for energy merely to stay alive is very low compared to that required for growth. The bacteria are unable to obtain sufficient energy from the remaining food in the liquid around them and they begin to metabolise food reserves within their own cells. The excess fats and carbohydrates are consumed first with the proteins later. As the energy level drops, the rate of f loe formation increases very rapidly. The free-swimming ciliated protozoa have a hard time finding enough bacteria to stay alive and they begin to die off. In the meantime, the stalked ciliated protozoa begin to grow and they predominate during the early phase of endogenous metabolism. More and more bacteria begin to die off. With
death, an intracellular enzyme dissolves a portion of the cell wall, allowing the nutrient contents left in the cell to diffuse out to furnish the remaining cells a little more food. Thus tysis allows the living bacteria to obtain nutrients from dead neighbours, but only after those cells are dead. The only part that remains of the bacteria is the non-degraded part of the cell wall and any non-tysed intracellular components. If aeration was allowed to continue, the bacterial population would continue to decrease. The free-swimming ciliates would die out completely and the stalked ciliates would start to decrease, but rotifers would start to increase as the rotifers have the ability to eat small particles of the floe and do not depend upon the individual cells, as do protozoa . Normally , the floe formed in the endogenous phase is separated by settlement, the concentrated floe being fed a fresh batch of organic matter. Since the quantity of micro-organisms is higher than the first time around the initial F:M ratio is tower and the bacteria start out at a higher point in the growth cycle . It is considered that, with constant time period of aeration , the system will progress a little further into the endogenous phase with each cycle . This results In better flocculation and a clearer effluent. Thus it is that the rate of organic removal is most rapid in the growth phase, while floe formation is best in the endogenous phase . NITRIFICATION DENITRIFICATION Long mean cell residence times, or sludge ages, in excess of twenty days, exist in the intermittent extended aeration system . Such conditions are conducive to nitrification. In nitrification a series of reactions convert organic and ammonia nitrogen to nitrate-nitrogen . In this bacterial process oxygen is drawn from available resources to allow the reactions to proceed. Aerobic conditions are essential for nitrification which occurs In two steps, by two highly specialised groups of bacteria (Nitrosomonas and Nitrobacter). Rate of nitrification is influenced by pH, temperature and the nature of the substrate. Denltrificatlon is a microbiological process in which nitrate-nitrogen is reduced to gaseous end products, nitric and nitrous oxides and nitrogen . Two different categories of nitrate reduction may be identified, assimilatory and dissimilatory. Assimilatory nitrate reduction occurs in bacterial systems in which nitrate-nitrogen is a source of nitrogen for synthesis and the released oxygen is thereby available for oxidation purposes. Dlsslmilatory reduction is the reduction of the nitrate-nitrogen with
Figure 1. IDEAL GROWTH CURVES
O A OW TH
~111.0WTHJI_ _ _ _ __
OIC:L INI Nlit
& NOOO &. MO\J S
P H.A. S f:
TIME - - -
OlC LI N ING
YiC. ' / :
&NDOGU,10\JS PH ... Sfi.
HAL........ <.."111C.RO â&#x20AC;˘O "lG,AN 1aMS
IA I I
Figure 2. LIFE CYCLE OF MICROORGANISMS AS A FUNCTION OF FOO D SUPPLY 0 1!1 P ERSf:O
- - - -- T I ME
Relative predominance of micro-organisms In activated sludge systems.
the nitrate ion fulfilling the rote normally occupied by oxygen in aerobic respiration. In other words, In the bacterial species that are capable of denltrlfying the presence of nitrate ion permits the microbial cell to malnta!n aerobic metabolism In the absence of free oxygen. The amount of asslmitatory nitratenitrogen reduction which occurs In acti vated sludge systems is minimal (being only that required for synthesis). Nitrate reduction is normally associated with dissimitatory mechanisms , usually occurlng oniy in an anaerobic environment. It Is possible for nitrate-nitrogen to be reduced In aerated systems If the micro-environment is anaerobic or nearly so . Intermittent oxygenation cycles may be used to produce an environment which alternates between aerobic and anaerobic (or nearly so) and In so doing
results in a significant toss of total nitrogen from the effluent . A cycle in which an oxygenation period of about tnree hours is followl!d by a period of non oxygenation for about three hours (settlement and effluent removal) is able to consistently produce total nitrogen removals In excess of ninety per car.it . By comparison , oxygenation at a reduced rate over the full four and a half hours, which Is available In a six hour cycle (so that the same equivalent weight of oxygen is transferred as in three hours oxygenation) results In a highly nitrlfied effluent . By a simple mechanical adjustment of the aeration frequency it is possible to produce an effluent of very tow total nitrogen content and at an Insignificantly low additional cost. Analyses of effluent quality from NSW Pasveer units are given in Table 1. Whilst such a high standard of effluent may not be required in terms of the Clean Waters Act la has been found that this form of denitrificatlon Is essential to reliable operation of the process. It should be noted however that in soft water areas nitrification, without denitrificatlon , gradually uses up the reserve alkalinity which may lead to conditions which change the sludge settling characteristics, better known as filamentous and bulking -sludge . PROCESS CONTROL Control is based on samples taken when the channel is fully mixed, from near the bottom water level, and allowed to settle for one hour In a one-titre measuring cylinder. The relative volume of S'ettled sludge , though not exactly that occurring in the main channel , Is used as the control . When It reaches about 70 percent , sludge.must be pumped out, and the sludge pump then adjusted to maintain about 50 percent . In some instances the removal of sludge, particularly In large quantl \ies, may result In an increasingly poor settling sludge. In such cases sludge removal should cease and the rate of oxygenation increased after which good sludge settling charact eristics normally follow. In most cases the reaction of the Pasveer Channel to changing conditions of BOD loading, temperature etc. is generally stow, being of the order of days or sometimes weeks. The settled volume test is aimed at maintaining a maximum of mixed liquor suspended solids within the channel without causing their IOl!S by enttrainment during effluent decantation . It Is also necessary to ascertain the level of solids contained in the channel so that the weight of solids, and hence organic loading, and settled volume index of the sludge can be assessed. Normally, a monthly monitoring frequency will suffice . Similarly a full 23
analysis of the effluent is required so as to gauge process efficiency and also to comply with licence conditions , in accordance with the Clean Waters Act , where no further stage of treatment is provided. Âˇ A well operated Pasveer Channel will exhibit a dense granulated dark brown sludge which after the one hour settling period will settle to less than fifty per cent of the volume of a one litre cylinder . The liquid above the settled sludge wil l normally contain a few light suspended particles and be otherwise clear. The settled volume as determined, will increase with time because of a gradual build up of solids in the channel. By regularly recording the rate of sludge build up and the solids content in the effluent, it is possible to use this test to determine when sludge should be removed from the plant. If the Pasveer Channel is not operating properly the mixed liquor may or may not exhibit a dense sett ling sludge but it will have a turbid supernatant liquor above the sludge. An effluent sample will generally contain more suspended solids than normal and will be cloudy. If the mixed liquor sample supernatant is cloudy and the plant effluent is cloudy , this condition may normally be associated with an inadequate supply of dissolved oxygen or a problem of loading. Dark grey or black sludge confirms a condition of insufficient oxygen. If, after sixty minutes, the sludge In the mixed liquor sample has settled only slightly, and appears to be light and fluffy, and the supernatant is clear there is more than likely a biological problem . The mixed liquor exhibits such a characteristic if the sludge is bulking or when undesirable organisms such as fungi are growing in the plant . They usually thrive if the channel pH or dissolved oxygen is too low . TYPICAL OPERATING VALUES
Generally , the usual continuous systems using gravity separation are somewhat limited by their inability to adequately concentrate the sludge thus imposing a limit on the maximum sludge return rate and the consequent level of solids that can be held in the aeration vessel. For example , with fifty per cent sludge return and a 'good settling sludge' assuming a practical return sludge concentration of about 10,000 mg/I, a MLSS of about 3,300 mg/litre in the aeration tank can be expected. At one hundred per cent sludge return this can be increased to about 5000 mg / I MLSS and at two hundred per cent return to about 6,700 mg/I. There is a practical limit to the amount of sludge return and further limitations occur with sludges having a high settled volume . The intermittent Pasveer extended-aeration system carries its own internal sludge recir24
BOD5 Susp. solids NH4-N, Org-N, NO3-N , pH Alkalinity as CaCO3,
DENITRIFIED EFFLUENT QUALITY
mg/1 mg/1 mg/1 mg/1 mg/1 mg/1
10 25 nil 2.8 1.2 210
4 15 nil 3.08 1.2 7.5
10 14 nil 2.8 0.8 7.5
14 15 nil 2.8 1.2 7.4
13 10 nil 2.7
NITRIFIED EFFLUENT QUALITY
BOD5 Susp. solids NH4-N, Org-N , NO3-N , pH
mg/1 mg/1 mg/1 mg/1 mg/1
7 20 nil 0.3 30.0 6.8
14 0.41 nil 38 .0 6.8
culation and compaction system and is therefore not so limited nor Is It as adversely affected by the high flow variability normally associated with domestic waste treatment . Pasveer channels of the type described above have found popular use for the treatment of domestic wastes, particularly in country centres, because of their relatively low capital and operating costs. The system may be used for multiple units in such applications as holiday resorts with large floating population. Power usage is of the order of 0.1 kWh/capita / day for the normal 6 hour cycle operation, 2 rotors at 160 mm immersion , or about $1 .1 per capita per annum . The inherent stability and simplicity of the Pasveer extended aeration system , especially at low organic loadings and because it approximates a cQmpletely mixed system, offers further benefit of low manpower costs both at the operational and technical levels . Operational involvement of only about five hours per week seems necessary. CONCLUSIONS
The intermittent system of extended aeration as used with the Pasveer channel is a versatile and simple method of treatment . The method has been found to be suitable for modular development for the treatment of domestic wastes for populations of up to about 10,000 capita. It is capable of producing a high standard of effluent treatment, either nltrified or substantially denitrified, the latter at very little extra cost and without the addition of extra chemicals. The potential of the intermittent approach to extended aeration treatment does not yet seem to have been fully realised. When compared with conventional continuous activated sludge treatment, which includes primary sedimentation, aeration,
7 8 0.14 0.14 34 .0 6.6
6 10 0.3 nil 19.0 6.7
13 nil 3.4 24 .3 6.6
2 nil 0.36 34.2 6.6
9 nil 0.6 33.0 6.0
secondary sedimentation and anaerobic sludge digestion (the total volume of which approaches 18 hours a.d .w.f .), it can be seen that similar tank volumes are involved. Coupled with the removal of the inherent complications of control which are associated with these separate unit operations of conventional treatment the intermittent system may be seen to be an attractive alternative treatment proposition. The intermittent extended aeration system, used in a deep rectangular tank modular configuration of the process can, by virtue of simplified geometry, offer a further benefit of maximum land usage and reduced costs of construction. The process therefore offers an inherently simple method for low cost, advanced level of treatment , which is especially amenable to the treatment of wastes for discharge to receiving watellS of limited dilution capacity . BIBLIOGRAPHY BAARS , J. K., "The Use of Oxidation Ditches for Treatment of Sewag e From Small Communi ties ", T.N.O., (Dutc h) Publication No. 179. BATTY, J., GORONSZY, M., and CLARKE, R. , " Development of The Pasveer Extended Aerati on System", The Shire and Municipal Record , November, 1974, 608. CHRISTENSEN, J., Paper presented at 7th International Conference on Water Pollution Researc h, Paris, September, 1974. GAUDY, A. F., et al " Studies on the Operational Stability of the Extended Aerati on Process", Journal W.P.C.F., 42, 1970, 165. GUILLAUME, F., The Ontario Wat er Resources Commission, Research Publicati on No. 6, July, 1974. HEUKELEKIAN H., Sewag e Works Journal, Vol. 14, 969, 1942. LESPERANCE, T. W., Wat er Work s and Waste s Engineering , May, 1965, 52. LUDZACK, F. D. , Journal W.P.C.F., 37, 8, 1965, 1092. PASVEER , A., Journal W.P.C. F., Vol. 41 , No. 7, 1969, 133. SOMMERS, J. A., Water Researc h, 2 1968, 563. ESLAKE, J., FITZPATRICK, W. Report on Overseas Tour to Study Extended Aeration Sewage Treatment May/June 1975 - Department of Public Works, N.S.W. SCHRO EDER and BUSCH, Journal W.P.C.F., 40, 11, R445, 1968.
AREA AND VOLUME ERRORS IN RESERVOIR PROJECTS K. G. Macoun
In reservoir planning and design it is necessary to determine the water surface areas and the storage volumes at various levels. Usually, graphs of areas and volumes are plotted against RL, having been determined by planimetering on topographical maps. This information is then used in other studies, such as reservoir yield, spillway operation and environmental studies and its accuracy influences the confidence which may be placed in the conclusions of such studies. Three principal cases arise. For investigation work it is desirable to know: (a) What mapping details (scale and contour interval) should . be called for in the survey of a potential reservoir site (b) What accuracy in reservoir volume estimation can be obtained using available maps. For design work it would be desirable to know: (c) What is the accuracy in area and volume at each storage level. The theory of area and volume errors in reservoir projects has been discussed in detail in Aguilar (1971). Assuming that topographical maps are prepared in accordance with the standards of the National Mapping Council of Australia (1953), and that areas on maps are measured by ordinary polar planimeter methods, Aguilar's key equations may be expressed in metric form as follows:
and are modified by: • map scale and contour interval • ground slope • the size of the area, or volume, being measured . From National Mapping Council (1953), map accuracy standards may be obtained as follows: (a )
20 , 000 ;
For S f ~
20 ,00 0 ;
crc~2 • (er/ •
crp = 0 . 3 mm ,
1000 _ _er..f.!
p2 • er t
which reduces to:
2 O't2) 2-n
in which : percentage areal error
percentage volumetric error
area of a figure (as planimetered), in mm'
contour interval, in m
map scale factor, eg , 1:S1 = 1:10 000
ground slope between successive contours
contour elevation standard deviation, in m
map planimetric position standard deviation at map scale, in mm
planimeter tracing standard deviation at map scale in mm
0 . 3 CI
Aguilar 1971 , Rayner and Schmidt 1963, and Davis, Foote and Kelly 1966 on the use of the planimeter indicate a value of O't of about 0.5 mm. Using these values, the factors appearing in equations A and B may be evaluated as in the following tables. Using equations A and B and the tabulated values for the factors it is a straightforward matter to compute the accuracy in areas and volumes for Case (c). For Cases (a) and (b) the order of reservoir volume can be assessed and the average ground slope, t, estimated from available maps or field inspection. Equation B may then be simplified to the form :
Jcr (~) •
0 . 5 4 mm ,
storage volume, in m'
It will be seen that the areal and volumetric errors depend on the errors in: • positions of details as shown on maps • the planimetric effects of errors in contour elevation • use of the planimeter Ken Maco un is an A ss ocia te with Rankin e & Hill Pty. Ltd. , North Sydn ey.
where k is a function of map scale, contour interval and average ground slope. Values Jor these factors are demonstrated in Tables 1 and 2. Equation D is shown graphically on the accompanying diagram for representative values of map detai!s and ground slope. If the ground slope varies markedly over appreciable parts of the storage basin caution must be exercised in applying this generalised relationship. As pointed out by Aguilar, it is important to realise that contour area errors and consequently volume errors are criti cally affected by ground slope . For a low ground slope much greater benefit will result from selecting a small contour interval than from choosing a large scale map (i.e. low S 1). Where the ground slope is very low, such as for natural lakes in inland Australia, the survey must be carefully designed having regard to the desired accuracy. In such cases consideration shou Id be given to alternative procedures, such as cross-section survey and volume computation by average-end-area method. This approach would also be suitable for gorges. Accuracy in volumetric determinations is generally of more significance than for surface areas as such . Surface area information is typically required for estimates of evaporation and water quality studies. Volumetric information is required for behaviour studies and affects dam height and hence cost. The accuracy of this information is obviously only one factor influencing the accuracy of -the final result. It is suggested that a volumetric accuracy of five per cent or better should be aimed at in planning studies and one per cent or better for final design studies.
TABLE 1 FACTOR
MAP SCALE FACTOR, S 1 (1:S~
EFFECT OF CONTOUR INTERVAL AND MAP SCALE
40 20 10 5 2
400 000 200 000
40 20 10
25000 12 500
6250 3125 1 250
4000 2000 800
1 000 500 200
0.0900 0.0225 0.0036
(<Ypโ ข + 0/)
Values for standard mapping details are bounded by sol id lines
TABLE 2 -
EFFECT OF GROUND SLOPE GROUND SLOPE, t
( 1000 oc1,,
0.3600' 0.0900 0.0576
900.0 225.0 144.0
36.00 9.00 5.76
9.000 2.250 1.440 0.562 0.360 0.140 0.090
1.440 0.360 0.230 0.090 0.058 0.022 0.014
0.3600 0.0900 0.0576
900 576 225 144
0.0225 0.0144 0.0056
36.0 14.0 9.0
The area of land to be acquired for a reservoir usually depends on the area inundated plus marginal areas required for flood surcharge and foreshore protection . Add itional areas may be acquired for catchment protection and in cases where unworkable remnants of the established properties would otherwise remain . In establishing the necessary area, cadastral information is as important as topographical information. At the design stage the r.eservoir perimeter at the top water level is commonly established by a special survey traverse. Consequently the errors associated with area determinations as discussed in the foregoing are not re levant for this case. In the preceding discussion it has been assumed that errors follow a Normal Law distribution. Also, by percentage areal (or volumetric) error we mean the ratio of one standard deviation of the error distribution to the absolute value of the area (or volume) expressed as a percentage, i.e. Ea
of a vo lume lies, simp le application of the Normal Law gives this range as plus or minus 1.65 Ev, Thus, if we want to select map detai ls so that there is a 90 per cent probabi lity that the volumetric error is plus or. minus one per cent we enter the diagram with a value of 0.61 per cent (i.e. one per cent divided by 1.65). For ready reference the following tabulation is given : Probabllity of True Value Lying within Specified Error Range
Error Range as a Multiple of the Standard Deviation
% 68 90 95 99
1.0 1.65 1.96 2.58
This means, for example, that there is a 68 per cent probability that the true value of a volume lies within the range of the computed value, plus or minus Ev. The diagram should be interpreted in this sense, but its use is not limited to such a range of errors. If, say, we wish to know the range of errors within which there is a 90 per cent probab ility that the true value
36.0 23.0 9.0 5.8
Project feasibi lity studies are to be carried out for a water supply reservoir which is expected to have a capacity in the region of 150 000 megalitres. Available mapping is at a scale of 1:25 000 and 10 metre contour interval. What volumetric percentage error can be expected from using these maps? Using the maps to run several cross sections in the proposed reservoir area shows that the ground slope is typically 0.2. Entering the di&gram at a reservoir vo lume of 1.5 x 10' Ml and using the line appropriate to the map details with a ground slope t = 0.2 gives a volumetric error of 0.55 per cent. This may be regarded as quite satisfactory.
Des igns are to be undertaken for a water supply reservoir having a capacity of about 30 000 Ml. It is required that the volume versus R.L. relationship be determined to better than one per cent accuracy at fu ll supply level. What specification should be set for surveying of the reservoir area? From the preliminary investigations it is known that the average ground slope is in the region of 0.03. From Tables 1 and 2, and using equation C: 1:5000
St ' ~000)
(1000 CTCi) St
Q000 O'C~ S1t
3 X 10'
This ground slope is fairly low, and beyond the scope of the diagram. However, inspection of the diagram indicates that a fairly large scale map will be necessar)": Try scales of 1:5000 and 1:10000 with contour intervals of two metres and five metres respectively. On this basis the standard map details of 1:5000 scale and two metre contour interval might be selected. It may be noted that if the average ground slope had been as low as 0.01 the volumetric error would have been 1.6 per cent for such mapping. However, the (slightly) non-standard map detai ls of 1:10 000 scale and two metre contour interval would yield a volumetric error of 0.55 per cent. Such mapping may be preferred for reasons of convenience in that the plotted sheets would be a more manageable size. If required they could also be brought to standard details by a two times enlargement.
(o-p' + 0'1') Ev
Aguilar, An tonio M., " Area and Volume Errors in Reservoir Project s" , Journal of the SurveylAg and Mapping Division , ASCE, November 1971. National Mapping Council of Australia, " Standards of Map Accuracy" , Canberra, February 1953. Rayn er, W. H. and Schmidt, M. 0 ., "Elementary Surveying ", Van Nostrand, New Jersey, 1963. Davis, A. E., Foo te, F. S. and Kelly, J. W. " Surveying Theory and Practice" ' McGraw-H ill , New York, 1966.
RE SERVO IR
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CONFERENCE CALENDAR AUSTRALIAN CORROSION ASSOCIATION "TECHNOLOGY TRANSFER AUSTRALASIA-ASIA" MELBOURNE - 13th-17th NOVEMBER (P.O. Box 110, Moreland, Vic. 3058)
AWWA SUMMER SCHOOL 1980 ADELAIDE 4-8 February "Water for the 1980's?" Secretary : Dr J. Cugley , State Water Laboratories, Private Bag P.O. , Salisbury, S.A . 5108.
UNIVERSITY OF QUEENSLAND INTENSIVE COURSE ON WASTE-WATER TREATMENT Chevron Hotel, Surfers Paradise, Qld, March 19-23, 1979 Principal Lecturers: Prof. W. W . Eckenfelder Jr. Vanderbilt University, USA . Dr. A . L. Downing - Binnie & Partners, U.K. Mr. C. D. Parker - Water Science Laboratories, Vic . Operation and Design of municipal and industrial systems, both biological and physico-chemical. Case studies . Problems . Course fee $325. Further information from :Department of Chemical Engineering , University of Queensland, St. Lucia 4067.
THE INSTITUTION OF WATER ENGINEERS AND SCIENTISTS 8-8 Sackvllle Street, London WIX 1 DD England
ENGINEERING AND THE ENVIRONMENT: HARMONY OR CONFLICT? London -
8th and 7th December, 1978
INTERNATIONAL WATER REUSE SYMPOSIUM WASHINGTON D.C. March 25-29th, 1979
Eighth Convention SURFER'S PARADISE 1-5 October, 1979
Call for papers : 500 word abstracts by September 15th, 1978 to: American Water Works Research Foundation, 6666 West Quincey Avenue, Denver, Colorado.
CALL FOR PAPERS
Synopses by 17 Nov., 1978 to Convention Secretary, P.O. Box 129 Brisbane Markets 4106.
UNIVERSITY OF MELBOURNE POST-GRADUATE COURSE ON ENVIRONMENTAL ENGINEERING
1 year full-time, or 3 years part-time. Further information from: Dr. S. J. Mainwaring, University of Melbourne.
ARTIFICIAL GROUNDWATER RECHARGE RESEARCH RESULTS AND PRACTICAL APPLICATIONS Dortmund, 15-18 May, 1979 Artificial groundwater recharge In 1ater management Quality requirements for Infiltration water of different origins Geological conditions for artificial groundwater recharge Meth ods and maintenance of inf iltrati on sites and plants Quality changes during Infiltration Quality changes during underground passage Legislation and regional planning Dr. Karlheinz Schmidt lnstitut fur Wasserforschung GmbH Dortmund
GROUNDWATER POLLUTION CONFERENCE -
PERTH, FEB. 1979
A Groundwater Pollution Conference has been organised under the auspices of the Australian Water Resources Council on the recommendation of the Technical Committee on Underground Water. The aim of the conference Is to provide a forum for discussion of the theory of transport and Interaction between solutes and microbiological pollution within aquifers and the application of this theory In the practical management of groundwater quality. The conference will be held at the University of Western Australia, Perth, from 19 February to 23 February, 1979 Inclusive. The conference is intended for technical specialists and managers concerned with groundwater quality with disciplinary backgrounds including engineering , geology and other environmental and earth sciences. In addition to a comprehensive programme of Australasian case studies and research papers, a number of experts have been invited to give keynote or state-of-the-art lectures. Dr. R. F. Kaufmann, Office of Radiation Programs, U.S. Environmental Protection Agency, Las Vegas, Nevada U.S.A. " Hydrogeologic Influences on the Long Term Disposal of Uranium Mill Tailings" (Keynote Address). Dr. H. Bouwer, Director U.S. Water Conservation Laboratory, U.S. Department of Agriculture, Phoenix, Arizona U.S.A. " Non-reactive Solute Transport in Groundwater", and "Reactive Solute and Materials In Groundwater". Profeasor F. Fenner, Centre for Resource and Environmental Studies, Australian National University, Canberra, Australia. "M icrobiologlcal Pollution of Groundwater". Mr. H. E. Hunt, Chief Engineer, Metropolitan Water Supply, Sewerage and Drainage Board, Perth, Western Australia. " Groundwater Quality Management". For further Information and registration forms please contact Mr. R. J. Hughes, Secretary, Groundwater Pollution Conference Organizing Committee, Department of National Development, P.O. Box 5, Canberra, A.C.T.
Handles Water Beautifully 1
"Len" Anthracite can be used:
Specific Gravity : 1.40-1.45 Acid Solubility: 1.0% (max) Effective Size: Type 2 0.85- 0.95mm Type 3 0.50- 0.60mm Uniformity Coeffj cient : 1.4 Voidage: 55%
0 To increase the capacity and efficiency of existing filtration equipment
0 To reduce the capital cost of new equipment
D For filtration of Alkaline Water: Caustic Acid Solution, Boiler Water and Oxidised Chemicals.
Distributed in Australasia by Kembla Coal & Coke Pty . Limited Box 1770, P.O. Wollongong, N.S.W. 2500. Telephone (042) 28 7455 Telex : 29172
AREYOU A POLLUTER? 14 Railway Parade, Oandenong, 3175. Phone: 791-2982
44 Koornang Road , · Scoresby 3179
Telephone 763 8988
l~ BOBY ANALYTICAL LABORATORY SERVICES
PETTIGREW CONSULTANTS PTY. LTD. Pollution Control & Water Treatment Engineers By the appropriate combination of impellers, impeller housings and methods of installation, the Model CS3126 can remove a wide variety of pollutants.
P.O. Box 94, Rocklea 4106 Telephone 200-1176
ENVIRONMENT PROTECTION AUTHORITY
And that's not all! With Flygt's wide range of models, the individual combinations are such ·that a Flygt Pump can get rid of your muck.
The Authority wishes to advise that as from 1 August 1978 significant changes have been made to the system of licensing waste discharges to the environment as a result of the recent passing of the Environment Protection (Amendment) Act 1978. The following are the main areas affected -
Consult Flygt on handling • trade wastes • sludges • effluents • comtaninated fluids etc.
FLYGT AUSTRALIA. LIIV.l:ITEI> A member company of the world-wide Flygt Organisation.
110 Carnarvon St., Silverwater, N.S.W. 2141 Tel.: 6471855
AUSTRALIA WIDE DISTRIBUTION NETWORK MELBOURNE HOBART LAUNCESTON 31 4077 34 3781 560 5333 ADELAIDE PERTH KALGOORLIE 278 2532 277 5111 21 2635
The introduction of the preliminary determination of licence conditions, prior to the finalisation of the licence. Provision for objections to the preliminary determinations to be lodged and, where appropriate, to be the subject of informal conferences.
An information sheet detailing these and other changes is available from the Licensing Section, Environment Protection Authority, 2nd Floor, 240 Victoria Parade, East Melbourne, 3002, or by telephoning 651 4178.
Our SUCCESS in supplying instrumentation to the water and sewerage industry is entirely due to our product range.
GREAT LAKES INSTRUMENTS: P.H. Turbidity, D.R.P. Conductivity. PORTACEL: Chlorination, Gas Leak, Residual. EMFLUX: Magnetic Flowmeter. McCROMETER: Water Flowmeters . BESTEL DEAN: Flumes, Weirs, Recorders. WESMAR: Lime and Alum Bin Levef Measurement, Non Contact Liquid Level Controls. DYNAMIC LOGIC: Automatic Telephone Alarm Devices. E.M.S.: Ultrasonic Portable Manhole Flowmeters. NEO-NU: Sludge Blanket and Density Meters. COMBINE with us and makes a SUCCESS of your plant. That is your and our ultimate aim. It's the way to SUCCESS.
Combined Instrument Systems (Australia) Pty. Ltd.
Telephone: 874-7030, 874-7039 874-6655, 874-6555 Telex: AA-31305
17 Thornton Crescent, Nunawading, Victoria, 3131.
TOTAL CAPABILITY IN
In Mechanical, Process and Biological Engineering Mechanical Engineering
Grit removal plant Screening press and bagger unit Circular and rectangular sedimentation tank scrape rs Sludge consolidation tank thickeners, mixing tank stirrers Sludge drying bed mechanical lifters Sand bed lifters
Thermal and chemical sludge conditioning plants TC Incinerator for screenings Multiple hearth , fluidised bed , rotary drum sludge incinerators Static grate incinerator Dissolved air flotation Carbon regeneration and absorption systems
Standardised activated sludge plant for small populations of up to 20,000 persons Extended aeration plant, Aerobic sludge digestion. Diffused air activated sludge plant. Automatic control systems for activated sludge plant
SIDDELEY ENGINEERING PTY. LIMITED Incorporated In NSW
Head Office: 262-284 Heidelberg Rd ., Fairfield, Vic . 3078. Tel. 489 25 11 Branches: Sydney• Brisbane • Perth• Auckland Hawker Siddeley Group supplies electrica l and mec hanical equ ipment with world-wide sales and service. Agents for Ha1ker Siddeley Water Engineering Ltd. (Templewood Hawksley Activated Sludge .)
MARTEK DIGITAL WATER QUALITY ANALVZER/CONTROLLER for multiparameter measurement and control and water and wastewater.
The Mark VII is a reliable portable Instrument for undertaking spot-tests, vertical profiles through water columns, bloassays, bore hole surveys, and long term measurement of water samples aboard floating laboratories, in water treatment and waste water facilities . It can also be used for In-situ measurements in water bodies such as rivers, reservoirs, ponds, lakes, coastal and inland waters, and sewage and industrial plant effluants . • Monitors up to four out of eight Interchangeable water quality parameters and will control two parameters . • Accuracy ±1 % of full scale. • Controls - ON/OFF with single or dual set points; adjustable dead band ON/OFF; and proportional control. • AC or DC power operation with Internal rechargeable batteries. • Portable or installed, unattended use. • Rugged , splash-proof construction.
SELBYS SCIENTIFIC LTD. Melbourne 544-4844
Adelaide 51 -4651
l<ENT flowmeter A general view of the pumps and in -ground storage tank of the Kent, Caringbah, Flowmeter Calibra tion Laboratory.
A unique facility available to all flowmeter users throughout Australia Registered for the calibration of flow meters with the National Association of Testing Authorities, Australia.
Kent Instruments (Australia) Pty. Ltd. Sydney (02) 525-2811 Adelaide (08) 352-1455 Melbourne (03) 874-1233 Perth (09) 277-5377 Brisbane (07) 36-1311 Launceston (003) 31-6733 Townsville (077) 79-3730 Hobart (002) 23 -2648 plus service centres at Canberra (062) 54-5258 and Morwell, Vic. (051) 34-4931
calibration laboratory • IS NATA registered P J 89 1 7
AQUA~GUARQ 4 Continuous Self-Cleaning Bar/Filter Screen FOR:
0 0 0 0 0 0 0 0
Sea, Lake & River Intake
Potable Water Treatment Primary Sewage Industrial Circulating Water Industrial Plant Effluents Industrial Process Liquids Industrial Separation Processes Harvesting Debris from Waterways
~)]l]:)1 PTY. 3 Bowen Crescent, MELBOURNE. 3004. AUSTRALIA Telephone: 267-1333, Telex : 31 -308
32 Hastie Avenue, MANGE RE, AUCKLAND, NEW ZEALAND Telephone: 633 -969, Telex : NZ -2473
Anziel represents in Australia: Anziel Aquasieve Nicholson Manufacturing Co. Rader Canada Ltd. Hymac Ltd. Bertrams Ltd. Messrs Cofpa Jylhavaara Engineering Works Moisture register company, Toyo Filter Manufacturing Co. Thwing Albert Instrument Co. Sternberg & Phillips Ltd. E. J. Cady & Co. Farrel Corporation B. F. Perkins & Son Inc.
Static Filter Screens Barkers, Chippers, Log Loaders , Chip Screens Pheumatic wood chip handling systems, Blowers, Feeders, Screens Pulp and Paper making machinery Paper Mill machinery Paper machinery felts TMP Systems-Fiberizing, Refining & Screening Moisture te5ting systems and machinery Self-cleaning Bar/Filter Screening Testing Equipment for printing industry Pulp Machines & Nozzles Paper machinery testing equipment Paper machine roll grinders Mullen board testing instruments
f.lE~T ~ S1-IARPLES
11 1 Study the basic features of a solid-bowl, continuous-discharge Sharples Super-D-Canter ® ~ centrifuge. 1 Internal design and operating G level selected for optimum performance on slu dge to be handled. Wide range of sizes. 2 Torque overload release is simple and can be reset without tools. 3 Provision for coagulant additions (internal or external) where optimum use can be made of them. 4 Selected hard su rfacing provided where needed most - feed ports of conveyor, feed zone, discharge ports, housing , fli ght edges and faces of conveyor. 5 All components designed to highest standards for operat ion over a wide range (up to 3100 x G) of G forces . G level selected according to type of slu dge. 6 Replaceable liners protect cas ing in solids-discharge area , and in the bowl opposite feed ports. 7 o ·n e-piece , heavy, cast- iron base reduces vibration.
8 Conveyor and bowl-speed differential infinite ly co ntrolled to optimize process performance. 9 Forced -feed oi l circulating system is floor mounted and connected to the centrifug e by fl exi ble connections. 10 Heavy-duty bearings, desig ned for long life, support rotating assem bly. 11 High throughput and cost/performance bec ause of many interna l designs and G leve ls ava il ab le. High est Sigma (poo l surface area x G) available . 12 Tungsten -ca rbid e feed-port in serts for long wear. 13 Heavy duty pl anetary gear boxes. 14 Automatic operat ional monitoring systems. 15 Tungsten-carbide tiles in beach area, if requ ired, for parti cul arly ab ra sive sludges.
The Sharples Super-D-Canter centrifuge is built to the highest standards with no-co mpromise design. Our philosophy is to give
water and wastewater treatment plants a cost-effective, rugged, and adaptable thickening and dewatering centrifuge.
As a result the.Super-D-Canter centrifuge is not limited by design, materials of construction , or abrasion protection to operate only at low G forces . Optimum G force can be selected for lowest polyelectrolyte cost, driest cake, most effective power, and least wear and tear. Stainless steel construction reduces maintenance and provides long life. And hard surfacing technology includes the new replaceable sintered Stellite and tungsten carbide conveyor hard surfacing with up to 20 times the abrasion resistance of conventional materials.
SHARPLES-STOKES PTY. LTD. 99 RESERVE ROAD, ARTARMON, N.S.W.
MAIL BOX 367, ARTARMON, N.S.W. 2064. PHONE: SYDNEY 439-3378. CABLE: PENNWALT, SYDNEY