Water Journal March 1979

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1ssN

0310 - 03671

Official Journal of the AUSTRALIAN WATER AND WASTEWATER ASSOCIATION Vol. 6, No. 1, Mar. 1979 Registered for posting as a publication -

Category 'B'.

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EDITORIAL COMMITTEE Chairman C. D. Parker Committee F. R. Bishop R. L. Cllsby Joan Powling B. S. Sanders A.G. Longstaff W. Nicholson J. H. Greer W. E. Padarin B. J. Murphy P.R. Hughes A. Wade J. Bales G. F. Scott Editor: Publisher: E. A. Swinton A. W. W.A

BRANCH CORRESPONDENTS CANBERRA A.CT. W. E. Padarin, P.O. Bo1' 306, Wo .{.. n, 2606.

NEW SOL TH 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. Nicholson, 101 Acton Road, Lauderdale, 7021.

NORTHERN TERRITORY 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.

Subscriptions Manager: F. R. Bishop, C/- Camp, Scott & Furphy, 390 St. Kilda Rd., Melbourne.

WATER

CONTENTS Editorial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Association News . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Computer Simulation of Brisbane River Qi Part 1 Salinity - R.O. Rankin and S.N. Milford . . . . . . . . . . .

Effect of Weathering on Oil Spill Identification - A.G. Fane, P. C. Lucas and R. M. Wood . .

Use of Service Reservoirs to Meet Water Supply Peaks - G. Cossins . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sulphide Control with Oxygen - D. C. Hutchings . . . . . . . . . . . . . . . . . . . . . . .

Conference Calendar . . . . . . . . . . . . . . . . . . . . . . . . .

People and Products . . . . . . . . . . . . . . . . . . . . . . . . .

7 8

9 13

17 19 22 22

INSTRUCTIONS TO AUTHORS

•

Articles should be of original thought or reports on original 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 available from Branch correspondents or the Editor. CSIRO Style Guide preferred .

COVER STORY Sugarloaf Dam will form an off-river reservoir of 95,000 ML live capacity adjacent to the Yarra River between Yarra Glen and Warrandyte , to provide pumped storage of water from the lower inhabited reaches of the river. It will be the first time that the Melbourne and Metropolitan Board of Works will be using water from an inhabited catchment and comprehensive water treatment will be provided.

The impervious facing of reinforced concrete will be placed on the upstream face of the 85 m high x 1000 m crest length main dam . The photograph shows the upstream face of the completed embankment which · has been prepared for concreting by rolling and sealing with bituminous emulsion.

Slip forming of the first bay of the concrete facing is in progress.

(Photo by courtesy of M.M.B. W.)

TECHTUM QUANTASPECTROMETER For the Measurement of Photosynthetic Active Radiation The Techtum QSM-2500 is a battery or mains operated quantaspectrometer designed for measuring radiation between 400 and 740 nm.

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Light measurements may be made under water to a depth of 100 metres by placing the optical unit in an optional underwater housing.

Designed for field or laboratory use. Supplied with control unit, optical unit and 4m of connecting cable. Accessories available include Fibre Optic Head for measurements In normally inaccessible areas and a protective housing for field use.

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WATER

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WATER

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!AUSTRALIAN WATER AND! !WASTEWATER ASSOCIATION!

FEDERAL SECRETARY P. Hughes, Box A232 P.O . Sydney South, 2000.

FEDERAL TREASu-RER J. H. Greer, Cl- M.M.B.W. , 625 Lt. Collins St., Melbourne, 3000.

BRANCH SECRETARIES Canberra, A .C.T. D. Coucouvinis, P.O. Box 306, ¡ Woden, A.C.T. , 2606

New South Wales P. J. Mitchell , C/- John S . Wi ll cox , G.P.O. Box 5222, Sydney, 2001 .

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, Adelalde, 5000 .

Western Australia R.J . Fimmel, P.O . Box 356, West Perth, 6005.

Tasmania P.E . Spratt , C/- Fowler, England & Newton, 132 Davey St., Hobart , 7000.

Northern Territory A. Wade , C/- Dept. of Construction, Mitchell St., Darwin.

WATER

EDITORIAL

- THE INDESTRUCTIBLE RESOURCE The Eighth Federal Convention of the Association will be held from 12th to 16th November 1979, at the Queensland Gold Coast, in an aura of friendliness and with a distinct Queensland flavour.

With the current awakening of the populace to the realisation that Water is our most valuable resource , Australia has come of age, and with it our Association. In a land richly endowed with mineral wealth , and with the capacity for high primary production, we have traditionally regarded water as our natural right - only recently have we seen it as our scarcest resource - one to be conserved and husbanded to the best of our ability.

It is perhaps fitting that our AWWA convention this year is being held in Queensland, which is one of the less-endowed states for water supplies, with vast arid regions, and a small population to provide the development capital. Queensland should therefore be in the forefront in this field of Water Resources technology.

Within the theme of the conference - Water, the Indestructible Resource - we will present a range of high quality papers, covering virtually every aspect of water, which will ensure the high standard of former conferences, with pleasant surroundings.

Overseas bodies such as I.A.W.P.R., W.P.C.F. and I.W.S. are developing an increasir1g interest in Australia, and indeed we are attracting more overseas registrants with each convention. This is the opportunity for the Association to become the umbrella for all interested in Water and Wastewater matters.

G. Cossins Chairman Eighth Federal Convention Committee

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- qua lifications su itab le for membership in the Inst. of Eng ineers, or other suitable professional bodies . ($12 p.a.) * 2. Associate - experience in the W.&W.W. Industry, without formal qualifications. ($12 p.a.)• 3 . Student . ($5 p.a.)

4 . Sustaining Member- an organisation involved in the W .&W .W. Industry wishing to sustain the Association . ($65 p.a.) * Plus State levy of $3 in N .S.W . and Vic. 1978/79 MEMBERSHIP SUBSCRIPTIONS NOW DUE

.,

VICTORIA This year's programme opened with a site visit on February 13th, taking advantage of Melbourne 's brief summer. About 80 members ploughed through sticky mud , wind and rain to view the progress at the Sugarloaf Dam , Yering Gorge intake , and Melbourne's first treatment plant. In fairness to Melbourne , the two preceding months had been beautiful weather , but it was just as well that the Board had the foresight to erect a marquee to house ¡ the plans and exhibits. Thanks to Bill Duller for organising the tour, and to Ranji Casinader and Barry Sheedy for explaining the technicalities of the dam design and the engineering works.

The March meeting discussed the sewerage systems of the rapidly developing Mornington Peninsula. Over the past 15 years works have been constructed with a present-day value of 80 million dollars. Frank McGuire and John Murray of G.H .D. described the organisation , construction and performance of the various works .

The April meeting features Bill Martin of Melbourne University , speaking on the modern theory of the slow sand filter, garnered during his recent sojourn with the Thames Water Authority.

On 22nd May , a half-day Seminar will be held, on the role of water and waste disposal ia the future development of liquid fuels . This will cover fuels from agricultural crops, and the demands of oil-from-coal plants of the future .

The Spring Break-out wil I be held in the Latrobe Valley, on the weekend of 12th-14th October.

NEW SOUTH WALES The Weekend Regional Conference for 1979 was based right in the heart of the Blue Mountains, opening in the now traditional manner of a golf afternoon, supplemented by bowls.

Over 90 members, families and friends attended , and all enjoyed the blend of social events, tours and site inspections, framed in the glorious scenery of the area .

The technical sessions for members naturally concentrated on the locality , with Neville Rees , of the Water Resources Commission, speaking on allocation of the Blue Mountain 's Resources, and John Tainsh of the P.W.D. describing the present water supply system , and various possibil- ¡ ities for its augmentation.

The area is predominantly "ribbon" development along the Great Western Highway , on the ridges of the 8

mountains , and this has posed a number of problems for sewerage systems , both technical and political , as outlined by John Clement and Kevin Tomlinson of the Blue Mountains City Council. The variety of sewage treatment works which have grown up since 1934 is itself an interesting history of technical development, and this was wel I described by Robert Chong , of P.W .D., who contrasted the complexity of the South Katoomba works (1934 vintage) with the simplicity of the Pas veer Channel at Valley Heights.

(1977). Paul Douglas (Sinclair Knight & Partners) discussed the technology of modern extended aeration systems.

All in all , a most successful conference.

The remainder of the programme planned for 1979 is set out below: 26th April : General Meeting - Subject Sirofloc.

23rd May: Technical ' Inspection , Kent Instrument & Testing Laboratory.

15th June: Wine Tasting - Len Evans Cellars.

18th July : Technical Inspection , Sydney Brewery.

22nd August: N .S. W . Branch Annual General Meeting.

21st September : N.S .W . Branch Annual Dinner.

23rd October: Joint Meeting with Institution of Engineers Aust. " Gosford Regional Sewerage Scheme", B. R. Jessop.

30th November: N.S .W. Branch Christmas Party - venue , North Sydney Leagues Club.

QUEENSLAND Queensland Branch is off in full swing for 1979. Five Branch General Meetings are proposed for 1979 and also the Federal Convention .

"Problems and Frustrations of Commissioning a Large Treatment Plant" Mike Lever (Brisbane City Council W.S . & S. Dept .

"P umps , Types and Uses" - Norm Clarke . " Water Quality Investigation of Pumistone Passage" - Matthew Miller (D.L.G.).

Three short papers from the Chief Chemist 's Laboratori es of B.C.C .

W.S. & S. Dept. - in typical Bill Solley fashion , these will be entertaining.

Latest news on Bill Garsden in Princess Alexandra Hospital is that he's giving cheek but sadly not kicking too well - Bill would like to see or hear from as many A.W .W.A . Members as possible his ward is S7 P.A. Hospital , Brisbane.

New members elected to A .W .W .A. in Queen sland since July 1978 to date include : Dan Kirkwood , Peter Lees, John Hanterink , Ross Kerr, Alwyn Wendt, Terry Hobden , Moray Galletly, Stan Lewis, Alan Pitt , Errol Thompson , Gary Williamson, Bill Williams, Russell Bateman , Graham Page , Perry Proud, Tim Sullivan , Geof Grace, Bob Macfie, Pon Jenson , Alan McPherson , N. R. Fox , V. E. Hobman , W . Little , P. G. Kidd, M. J. Damrow , Bill Gibson , Ashley Knight, David Freeman, Albert Moore , Ronald Connole , David

Protheroe, R. L.. Brook, B. S. Elvery, R. S. Hicks , M. C. Miller, D. B. Reece, Philip Hennessey , L.'W . Thompson, W. Pitcher , P. G. Warmen , P. Azzopardi, G. Wrzochal , A. E. Pettigrew, A . J .

Sharry , and R. H. Grimley.

The Queensland Branch welcomes you to A .W .W.A . and hopes to see you at our General Meetings if you are in or near Brisbane or hear from you if you reside in the country .

SOUTH AUSTRALIA On 30 .3.79. The S.A. Branch was addressed by Mr. Chas. Allen, Planning Engineer with the Water Resources Branch of the E. & W .S. on the subject of River Murray Salinity . Mr. Allen briefly described th geological and anthropogenic causes (wei rs , irrigation) of salination of the river and out I ined the proposed program of engineering and other measures to decrease the rate of salination in the S.A . section of th e river.

Appro ximately 30 members attended.

PRESIDENT'S REPORT Change! Where is AWWA going?

Change has always been with us . But what often leaves us breathless today is the rate of change . We must move forward with this change . We cannot afford to become an Association of middle-aged complacents.

We need to look to the future, not the past or even the present! We need new , sound and workable ideas . We need young blood. Above all we need results - we are accountable!

AWWA is unique. We are more than just chemists, engineers, biologists or doctors . We are all of these disciplines and others rolled intCY one very special body, with the broadest view of society and the environment.

We have a supreme role to fill - if we genuinely wis ~ to fill it.

What is being done?

At a meeting of Federal Councillors joint discussions were held with the International Association for Water Pollution Research (IAWPR) . As a result a co-ordinating body has been formed which will also include affiliation with the Water Pollution Research Federation (WPCF) , the International Water Supply Association (IAWS) and the Australian Academy of Technological Sciences (ACTS) . Other bodies will be included as the opportunity allows .

A most important step also is the formation of Special Purpose Committees at State Branch Level working with the Federal Councillors for that state.

All States are involved . This is seen to overcome some of the ponderous inertia which can exist when Federal Council meets only every six months . It transfers some of the responsibility and authority of Federal Council to the State Branches.

The strength or weakness of AWWA lies with its members, that is us. We will get out of AWWA in direct proportion. to what we are prepared to put into it!

WATER

COMPUTER SIMULATION OF BRISBANE RIVER - PART 1. SALINITY

by R. 0. Rankin and S. N. Milford INTRODUCTION It is not possib le to predict accurately the rate of dispersion of pollutants in an estuary by purely t heoret ica l ca lcu lations.

However , by using a natural or artifica l tracer, the dispersion characteristics of a particular estuary can be determined , so that subsequently the level of various pollutants can be predicted by means of a theoretical model. This paper describes the one-d im ensional mathematical modelling of salinity concentrations in the estuary of the Brisbane and Bremer Rivers System in order to estimate the magnitude of the dispersion of the tracer tak ing place. The resultant dispersion characterist ics cou ld then be used in the prediction of disso lved oxygen levels along the length of the estuary. This modelling of dissolved oxygen wil l be discussed in a subsequent paper .

REASONS AND AIMS FOR THE INVESTIGATION To understand the physical processes invo lved in est!Jar ies , mathematical modelling techniques have bee11 adopted in recent years. Ultimately , the objective in modelling a complex system is to be able to predict system responses to a certain change in the environment before it takes place . In this way , models have a decided financial and time-wise advantage over their prototype equivalent .

In this study, the Brisbane River Estuary has been chosen for investigation because the size and concentration of industrial and domestic activity are representative of severa l Australi an waterways. This river is of particular interest since it is the site of the City of Brisbane (the centre of wh ich is. located 30 km upstream from the mouth) and thus a sink for many of the city's industrial and domestic wastes . The city has a population of about three quarters of a million. The Brisbane River has a major tributary , the Bremer, which f lows through the cen(re of Ipsw ich, a major satellite town of Brisbane. The two estuar ies combi ned form a Y-shape .

MODELLING PROCEDURE For the purposes of modelling the River mathematically, an exist in g water quality computer model has been used.

Several alterations to th is model have been made and these are later discussed. The modelling of salinity is first considered , and the model adjusted to give good agreement with collected fie ld data. Sa linit y intrusion is a function of tidal conditions and freshwater in i low , and the model has been tested for all tidal phases, as we ll as from dry to average freshwater flows. Very large flow per iod s, as found in times of flood , have not been modelled as , in these conditions, stratification of sa linit y leads to a condition not al lowed for in this model - that of a vertiGal concentration gradient.

Through this modelling of the sa linit y distribution , va lu es for the dispersion characteristics for the Brisbane/ Bremer System are obtc1.ined.

THE BASIC MODEL, M,odels of tidal waters are classified by Hinwood and Wallis (1975) in five gro up s: (1) zero - ; (2) one-; (3) two (p lan view)- ; (4) two (side elevation) -; and (5) three-dimensional . Within these groups, three different spatial reference frames are used: Eul erian; Lagrangian ; and co nstant upstream vo lum e. Considering the inh erent limitati ons on the accuracy of the present investigation, only a one or two dimens ion al plan view model was ju st ifiabl e.

Robert Rankin is now the Education Producer, Australian Broadcasting Commission, Brisbane. This paper is derived from his Master's thesis under Dr. Neville Milford who is the Reader, Department of Physics, University of Queens land.

WATER

The United States Federa l Water Quality Administration (FWQA) model (Fe igner and Harris 1970) was chosen because of its wide acceptance for predicting hydraulic condi tions and quality constituent distributions. It is a model which can effectively handle a two-dimensional plan view bay or estuary by using a ' web ' of inter-connected channels and junctions. Here the geometry of the estuary allows reduction to a one-dimensional model without seriously affecting model predictions within the accuracy of this study . The model belongs to the two-dimensional plan view Eulerian category. If an estuary has a fairly regu lar channel and is much longer than it is wide , one-d im ensional models can give accurate descript ions of the hydraulics and constituent transport provided it is a we ll -mixed estuary. Since it assumes that disso lved or suspended constituents are we ll -mixed over every cross-section , the one-dimensional representation will lead to errors in predicting the distribution of constituents which enter at the sides of the estuary. Despite this limitation , many one-dimensiona l models have been developed because of their simplicity and economy. In its original form , the FWQA model was developed and tested by Shubinski et al. (1965) using very limited data from the Sacramento¡ San Joaquin Delta. The basic model used in this in vestigation , developed by Feigner and Harris (1970) , was applied to both San Francisco Bay-Delta and San Diego Bay. Here model and prototype agreement was cons idered to be good.

Discrepancies due to the use of avai lab le data (averaging tides , non-representative samp lin g points) were apparent, but it was not possib le to determine what proportion of the discrepancies was attributab le to the theory of the model itself .

Dailey and Harleman (1972) discuss the disadvantage in the model of the need to specify the ocean boundary for a quality parameter over the full tida l cyc le. This poses a problem for phenomena such as sal ini ty intrusion and waste d isposal near the boundary - two conditioris met in the present study of the Brisbane/ Bremer System.

The boundary valu e prob lem ar ises in all estuary model lin g. It can be solved by using a comp lete set of measurements along any 'open ' boundary , whJch means that ' hindcasting ' rather than forecasting is possible.

If boundary measurements are not avai lab le, another technique is to choose a model boundary far enough from the region of interest that conditions there do not significantly affect the results. While this is poss ibl e for the Brisbane River, it makes the model many times more comp li cated and expensive , since it involves modelling Moreton Bay, with an area of one thousand square kilometres. It was decided not to include Moreton Bay in the present exploratory models . However , the same FWQA model has in fact been used , in a two-dimensional plan view representation ,

by Milford and Church (1977) for pre liminary investigation of Moreton Bay itself. The model gave exce l lent results in predicting the hydraulics for the Bay , but the predicted sa lini ty d istrib1Jtions showed on ly fair agreement with the measured va lu es due , in part , to problems with the artif icia l dispersion which is numerically generated within the mod el , and in part to the fact that the salinit y is not uniformly mi xed in the vertica l direction .

The FWQA model consists of two separate but related parts, hydraulic, and quality. In the hydraulic model the motion of the water is computed and a summary of the flow parameters formed. The quality sect ion for the mot ion of the constituents is then run using these hydrodynamic conditions. In this present study we are only concerned with the qualit y section. Hydrodynamic conditions have been com puted with good accuracy using data from nine tide gauges situated along the river (Cain , 1975) .

9

DISPERSION CONSIDERATIONS In the quality model , the river system is divided into a number of finite length channels (or elements) inter-connected by junctions , and conservation of mass within the model is maintained at these network junctions. A passive tracer in a · body of water is transferred from one point to another by the mechanisms of advection and diffusion . Transport by advection is the movement of the constituent by the bulk translation of the water in which it is dissolved or suspended. Transport by diffusion is dependent on the ex isting concentration gradient and is effected by the mechanisms of molecular and turbu len t motions. In natural streams, t he turbulent component due to water eddies is much more sign ifi cant than the molecular component, so that molecular diffusion can be neglected.

Under the usual assumptions of turbulent diffusion theory , the rates of change of the concentrations at a point due to advection and diffusion are , respectively (Shen, 1971 ),

ac

at

- ac

where C 1 = const ituent concentration in the transported volume CN . 1 = upstream junction concentration CN = downstream junction concentration .

In the present study , this process has been altered to give more control over the magnitude of the longitudinal dispersion. Bella and Grenney (1970) ca lculated an expression for this numerical dispersion , starting from a single load of constituent in one element, and considering only uniform flow in a channel of constant cross -sectiona l area. They found that for this particu lar case the dispersion cou ld be represented by a pseudo-dispers ion coefficient , Op, given by

Dp =

¥{(

1- 2y)

t:,x -

U t:,t}

(5)

Figure 1 shows a plot of DP against U tor three values of

Y, with /;;. x and /;;. t being the values used in the Brisbane/

= -U dX

(1)

Bremer Model: 6x = 3000m.and /;;.t = 1800s.

and

ac

at

=

Kd

a2 c ax 2

(2)

where x is the distance along the axis of the (one-dimensional) estuary, U is the mean velocity and Kd is the diffusion coefficient, assumed to be independent of the time t , and to have a constant value over each channel length even if it varies from one channel to another.

In addition , a phenomenon known as longitudinal dispersion also exists and is due to the shearing motion between adjacent transverse and vertical layers in the velocity profile.

The effect is to shift differentially the adjacent layers of constituent longitudinal ly along the stream ; simultaneously the constituent is mi xed between layers by turbulent diffus ion. In th e mode ls where the water ve loc it y is assumed constant o.ver the cross-section (as in the present model) , this dispersion effect cannot be specifically represented in the advection term . One possible method of representing this dispersion is to use an equation similar to the turbulent d illusion equation , namely

Y= ·25

'v,

E c..

Cl

cII

u

.

.;::

05

.....

0

u

C

(3)

Y:033

N

~

Y:0·40

-so

~

c.. !!)

"O

where Ex = the associated longitudinal dispersion coefficient, and in genera l , Ex> Kd .

The FWQA model does not use this method . Th is model re li es entirely on the so luti on of the transport eq uat ion (1) to supp ly a numerically -ge nerated lon gitudinal d ispers ion .

Thi s dispersion occurs in the procedure because in each timestep /;;. t in the finite differe.nce solution , the constituent is transported one whole element wh ereas the body of the water may only travel a fraction of an element . This occurs for the general case where u /;;. t > /;;. x where /;;. x is the length of an element. In the FWQA model the concentration of the constituent transported from one junction to the next may be chosen to be any concentration that occurs within the boundaries of these junctions , and this is the method used in the FWQA model to control the leve l of longitud inal dispersion .

A valu e of Y = ¼ was used throughout, where Y is the constant used to determine the transport ed concentration C ' in the model, and

C'

=

(1 - y) CN-l

+

yCN

(4)

I

0 "O -

.

::::,

er

Velocity , U(m s-1 ) Fig. 1. Plot of pseudo-dispersion coefficient, DP against velocity,U for three values ofY.

Average values for DP were ca lculated for the corresponding valu es of V using an express ion for average DP derived from the Bel la and Grenney equation :

TT/w

D

p

=

f

U ~

(l-2y)

t:,x -

0

U t:,t}dt (6)

dt 10

W.A,TER

At any point along the river, the ve locity profile through a tidal period can be approximated by a sine function, with only its ampl itude varying alon g the river . Thus the current ve loc it y can be expressed: U = Umax sin wt where Umax is the maximum velocity at the particular po in t over one cycle.

On integration , eq uation (6) becomes ;

op

U =

max

(l-2y)tix 'TT

u2max

lit

(7)

4

Using values for Umax (0.2-0.5 ms ·1) obtained from runs of the hydraulic model , average va lu e·s of DP were calcu lated along the ent ire river for various va lu es of Y. Each set of va lu es for Dp (for one value of Y) was averaged giving an overal l d ispersion va lu e tor the river. These are listed in Table 1.

TABLE 1 Average values of pseudo-dispersion Brisbane River) with var io us Y values. y·

0.00 0.25 0.33 0.40 0.50

coeffic ient

DP (for

Op (m 2 s·1) 315 112

30

44

STORY BRIDGE

-8 -89

In representing longitudin al dispersion in the Brisbane/ Bremer Model , DP is made fairly sma ll , but st il l positive, by choosing Y = 0.33. Additiona l lon gi t udinal dispersion is introduced through the coefficient Ex. This is incorporated with Kd in the diffusion equation (2) to form a combined coefficient (Ex + Kd)This method was found to be more sat isfactory than using only the quarter point value of Y throughout (as in the original FWQA model) since this gave erratic resu lts, generat in g too much dispersion in some hydrodynamic cond itions and too littl e under other conditions.

INPUTS TO THE MODEL At the seaward boundary , a tidal fluctuation of the water leve l is specif ied . Four ier ana lysis of tide height data generated a sem i-diurna l and diurnal component. Tides were averaged over a seven day period and during the modelling periods of 21 days, the tidal characteristics were therefore altered three times. A simil ar Fourier analysis was supplied to sal inity measurements near the mouth of the river, and the resulting smoothed diurnal and semi-diurnal salinity variations were used as the salinity boundary condition.

It was considered that a channel length of 3 km was adequate to in vestigate the quality processes, considering both the, approx imation s made in the mod el theory and the amount of prototype data ava il ab le. The model consisted of 35 channe ls with th e conf luence of the two streams occurring after 25 channels from the mouth of the river. The model extended for 4 channels in the Upper Brisbane River and 5 cha nn els in the Bremer Ri ver , terminating with the tidal limit in both these rivers.

Flow rates from effl uent outflows and creeks were spec ified at appropriate junctions. This also app li ed for the terminating junctions at the tidal limit.

DISPERSION OF SALINITY IN THE RIVER For the purpose of calcu lating dispersion, it was considered desirable to al low for the variation of dispersion along the river. In order to do this at a leve l of comp lexity justified by the accuracy avai lab le, the system was divided into three sect ions so that the dispersion characteristics could be chosen in the three sections independently. The divisions were made by taking into acco unt the physical structure of the river and by in vestigating salinity field data, both of WATER

which acted as guides to the dispersion characteristics.

The first and second sections conta in ed the first six and next four channels respective ly , and the third section contained the remainder. Ca lcul ations were carried out to determ in e the influence of the dispersion on the concentrations. Figure 2 shows the sensitivity of the model to changes in the dispersion coeffic ient at two monitoring points , and presents associated field data. One location is at the Story Bridge (Junction 9) near the centre of Brisbane , and the second is at Tennyson (Junction 14½}, these being respectively 27 and 44 km from the mouth.

For the Story Bridge site, an increase by a factor of 2 .6 in the dispersion coeff icient increased the rate of chanqe of average dail y sa linity concentrations from - 0.09g 1-1 day-1 to 0.16g 1·1 day ·1. At the Tennyson site, an increase by a factor of 2.1 in the Kd va lu e increased the rate from 0.13g 1·1 day ·1 to 0.38g 1·1 day·1. Model pred ictions of daily sa l in ity averages were compared with field daily averages at the same two locations for two periods , _each of 21 days.

The first period is one of rather normal equilibrium conditions with a low flow whereas the second is a case of higher flow

+

.:1:.:1:.......::=.:::::~=*=~*:=:=== Kd = 254 * Kd:99 +

+

+

+

+

+

........

0)

10

+ +

+

+

+

+

+

-+

+

+

Kd: m 2 s· 1

o-~-~-,::-'::--~___.~,..........---L._ _..__.____._........___, 00

1/9/74

TIME (days)

00 10/9/74

Fig. 2. Sensitivity of the model to changes in the dispersion coefficient, Kd at two monitoring points, with associated field data (daily averages).

One of these periods is shown in Figure 3. The transients occurring each seven days were produced by the sudden changes in the boundary conditions, as discussed ear li er .

The period illustrated in Figure 3 had an average aggregate flow rate of 2.46 m3 s ·1 from the Brisbane and Bremer Rivers , and occurred after a period of steady state and relatively constant flow. The second period had an average aggregate flow rate of 3.80 m3 s·\ an increase by a factor of 1 .54. Dispersion coeff ici ents were computed separately for each period for each of the three sections.

11

river and instantaneous f luctuations at part icu lar locat ions we re also investigated. Figures 4 an~ 5 show typ ica l situations for each of these respectively.

STORY BRIDGE (Jn9)

+

+

+

+

+

+

+

+

+

*

+

TENNYSON (Jn 14½ l

+

+

~+

+

+

+

+

+

+

+ -----+----~+ + +

00 1/9/74

+

+

+

+

+

+

TIME (days)

00 15/9/74

Fig. 3. Model predictions (co ntinuous line) of daily salinity averages compared with field data. deviation as a perce ntage of the mean pred icted conce nt ratio n for th e period .

Th e largest discrepancy occ urred w ith pred ictions at Tennyson. Here, sa linity leve ls are general ly low . This , co up led w ith the fact that Tennyson is c lose to the sa lt intru s io n l imit , prod uces a diffi c ult mod el l ing s itu atio n .

Co rrelatio n w ith lo ngitudin al fi eld s urveys alo ng the length of th e tidal

Table 2 s ho ws th e d isc repanc ies betwee n th e predic ted and prototype for sa l in ity for the two 21 day per iods ; the Tab le I ists the mean deviation betw een t he two curves, th e st andard deviation 1 t:,,C = - ( I Cp red- I Cproto) n where n = number of paired va l ues (S.D.) of th e abso lute deviations , the R.M.S. deviation , and th e R.M .S.

TABLE 2 D iscrepanc ies in sa linity predictions at two sites for two 21 day period s.

(Units: g 1·1).

T ime

Site

Mean Dev iation

30 /8/74

Story Br idge Tennyson Story Bridge

Period

to

20 /9/74 16 / 10/74 2

to

S.D .

-0.68

0.87

1.29

5 .7%

0.52

0 .47

1.06

14 .2%

- 0 .25

0.67

1.1 0

5.4%

0.31

1.09

1.84

30.4 %

Tennyson

7/11/74

(a)

CONCLUSIONS The mathematical m ode l can adequate ly simu late trend s in sa linity as lo ng as the freshwater inflow and tida l bou ndary cond it io ns are know n, prov ided that the sal inity stratif icatio n is not large. Dispers io n coeff ic ients can be ad ju sted to suit the appropriate co nditi o ns (river f low, location in river, etc.). Co · rect d ispersio n coeff ic ients have been derived for the m odel on ly as far along the ri ver as the limit of salt intrusion. Above this limit , a constant va lu e has been assumed fo r Kd. A ny sub seque nt m ode llin g of pol lutan t s us in g these dispersion coef fici ents may have disc repancies in this upper sect ion.

•

LOW WATER 25/10/74

-Predicted + Field Data

+

>Iz 1

% RMS Dev iat ion of predicted

RMS Deviation

In th e li ght of the fact that sa lin ity concentrations varied ove r a range from 30 g 1·1 to less than 1 g 1·1 w it hi n t he river system , correlation between t he predicted and prototype sa lin ity levels was considered to be w ithin the limits expected for a model with flows averaged over 7 day per iods , with no more than 3 different dispersion coe fficients used , and with severa l ot her s im pl ifying assumptions . Severa l of t hese restrictions ca n be removed eas ily , albe it at the expense of add iti ona l computat io~al expe nse , and would almost certa inl y lead to a signif i ca nt improvement in th e agreement. Th is was not required in the present investigation because of the eve n larger un certa int ies invo lved in the modelling of pol lutant distribution (see subseque n1 paper).

3

::J

+ ++

<(

Story Bridge +

<.I)

++

+

..

- Pred1ct1ons + Field Data +

++

(b) HIGH WATER 30/10n4

+

+

+

'

El1 ~

cu

"'O

~

__,

<(

Ol

c::0 vi

<( <.I)

5

10

<.I)

C7)

0 ~ I

15

20

25 Junction

Fig. 4. Comparison of model predictions with longitudinal field surveys of sa linity .

12

++

z __,

C7)

>z

I-

11 hrs

20/10

00 21/10

00 22/10/74

Fig. 5. Comparison of model predictions with instantaneous field measurement of salinity .

WATER

.

THE EFFECT OF WEATHERING ON OILSPILL IDENTIFICATION IN AN AUSTRALIAN MARINE ENVIRONMENT

by A. G. Fane, P. C. Lucas and R. M. Wood INTRODUCTION Oil sp ill s present a major pollution problem. On a worldwide basis it is estimated (Anon . 1977; Wardley-Smith 1976) that from 0.1 to 0.25 % of total oil production is lost , that is 2.6 to 6.0 x 10s tonnes/year. Australia, with its widely distributed coastal population , could experience oil spillages of the order of 10 4 to 10 5 tonnes/year.

The probability of oil spi llage is relatively high in busy ports , such as Sydney Harbour , where many oil transfer operations occur . Although massive spills fortunately are a rare occurrence, there are frequent minor to moderate losses between tanker and terminal, during the bunkering of ships , and due to careless pumping of oily bilge water . Many of these losses are of oi I products rather than crude oi I. · Legislation enacted by the Federal and State Governments aims to control the problem , by vesting in the various statutory authorities power to prosecute those responsible for the oil spills . However , the burden of proof is placed on the authorit ies , who have to rely on observation coupled with analytical spill-identification techniques.

The major difficulty with spill-ident ification , or fingerprinting , is that the multicomponent oil mixtures change with time after spillage . Although considerable work has been done overseas (Berridge et al . 1968; Button 1971 ; Gordon et al. 1976; Sivadier and Mkolaj 1973; and Smith and MacIntyre 1971) on the ' weathering ' of oil slicks, little has been done in t he local env ironment , particularly with oil products rather than cr ud e oi I. In this paper we present results which show the rate of change of some of the characteristic chemical properties of oils when exposed to the local marine environmen t . We also discuss the effect of these changes on the probabi lity of identification of a particular oil.

EXPERIMENTAL Two oils were selected for study, light marine diesel oil (typical of the oil products) and Kuwait Crude (typical of the imported crude oils) . Weathering experiments were carried out on an island in Sydney Harbour, in an open tank (1 .0 m wide 1.5 m long x 0.3 m work in g depth) with a constant flow (ca 101/min) of sea water. Furth er details may be found elsew here (Lucas (1978) ).

The cGlnditions in the weathering tank were chosen to simulate an oil slick floating on a large volume of sea water.

Sufficient oil was poured onto the surface of the water in the tank so as to produce a layer of oil init ial ly about 1 mm thick .

Th e weathering of the oil was allowed to proceed for about two weeks and oil samples were taken, initia ll y at hourly intervals , the daily, and the last few samples were taken at 2-3 day intervals as the changes in oil properties became smaller. .

The samples were analysed by Gas Chromatography and Infra-red Spectroscopy. Oetai Is of the analytical equ ipment are given in Appendix I . In add ition the refract ive index (n) , density (d) and molecular mass (M) were determined so that the ASTM n-d-M method 03238-74 could be used to calculate the proportions of structural groups (aromatic and napthenic rings, as well as paraffinic chains) in the oil samples.

(School of Chemical Engineering, University of New South Wales)

WATER

RES ULTS AND DISCUSSION (i) Gas Chromatography A GC of light marine diesel oil (LMOO) is shown in Fig . 1.

The normal paraffins are the best resolved and most easi ly recognised components as they appear superimposed in a regular array upon an unresolved envelope of paraffin isomers , naphthenes and aromatics of complex _structure .

Fig. 2 is the GC of the oil after 340 h of exposure in the tank at an average water temperature of 15 deg . C. Nearly all the hydrocarbons up to C12 have been removed as well as some of the c,, and c,. components .

Comparison of GC res ults for LMDO at an average temperature of 22 deg. showed that in this case all of the c,, and most of c,. components had been eliminated .

Similar GC results were obtained for Kuwait crude oil after the oil had been weathered for 393 h at 17 deg . C .

Again the light components up to c,, were eliminated as was found with the LMDO. Due to the differential nature of weathering of a multi component oil mi xt ure , analysis of the results is facilitated if the co ncentrat ions (peak heights) are considernd relative to one component. The c., fraction was chosen as reference since it is fairly inert and is sufficiently abundant to minimise errors in peak height determination . A semi-log plot of normalised concentration (peak height for given hydrocarbon/peak height for C11) versus time yielded straight lines , which gives the simple exponential decay; C

=

Ce-kt

where C is the normalised concentration, and k is the rate , constant.

Data for the rate constants for the LMDO components together with vapour pressures are given in Tab le 1. The results show a reduction in the magn itude of the rate constant , k with increasing carbon number•and an increase with t~mperature. (The small , negative , values of k for heavier compo nents C,a - c,, imply that they_are more inert than the reference component, C11).

Loss of components by evaporation would require the rate constant , k, to be proportional to the vappur pressure, P. Table 1 does show that the ratio (k/ P) is reqsonably constant for c,,.c,, at both temperatures. Although the solubility of hydrocarbons in water increases with temperature, the slope is considerab ly less than that of the vapour pressure/ temperature curve. Thus Table 1 provides strong evidence that evaporation is the primary cause for the reduction in the amount of the lighter hydrocarbons during weathering. (ii) Structural Group Analysis by n-d-M Method (ASTM (1974) )

Viscosity , refractive index and density variations during weathering were measured for two samples of LM DO at 15 deg . and 22 deg. C. The refractive index and density va lu es passed through maxima (at - 130 hrs for the 15 deg. and - 50 hrs for the 22 deg . weathering) which could be due to a reduction in total aromatics offsetting the general trend towards a higher molecular weight distribution for the "."'eathered oil. Calculations based on the n-d -M method did indeed predict this trend·. "Figure 3 shows the calculated data which indicates a drop in the amount of aromatic ca rbon , CA, which was more or less balanced by an increase in naphthen es, CN. The percentage of paraffins remained fairly constant .

13

TABLE 1 First Order Rate Constants and Vapour Pressures for L.M .D .O . Components

Temperature 15 deg . C Vapou r Rate Constant Pressure Ratio k (h 路1) k/(P x 10路3) k/(P x 10路3)

Component C11

0.035 0.017 0.006 0.002 0.0006 0.00009

c,, C" Cu

c,. c,. c,. c,.

-

-

C20 C21 C22

- 0 .00029 -0. 00028 -0 .00039

Vapour Pressure P (Pa)

Rat e Constant k (h 路1)

-

-

-

Ratio k/(Px10-3)

-

-

-

1.2 1.9 1.9 2.0 2.1

30 8.8 3.2 1.0 0.28

-

Temperature 22 deg . C

1.4 1.9 2.2 2.0

16 5.7 1.8 0.50

0.022 0.011 0.004 0.001 0.0004 0.00025 0.00028 0.00033 0.00042 0.00047

-

-

lmV

Squalane

Solvent nC17

nClS nCl6 Squalan e (Int. S td. )

nC18 nC 19

nC1 4

nC 14

nC ll

nClS

nc

7

nC20 n

6

nC12

nCll

nC21

n 18 nC19

nC20

nC2 l nCll

12 16 Thie - Minutes

20

,.

I

12

"

Fig . 1. Gas Chromatogram of L.M.D.O. (Unweathered) .

I

16

20

I 24

I 28

Thie - Minutes

Fig. 2. Gas Chromatogram of L.M .D.O. after weathering for 340 hours at 15 deg . C.

TABLE 2 Nominal Band Assignments - Crude Oils (Mattson et al. (1970) )

Wave length (cm -1) 3100-3600 3050 2950 2925 2850 1700 1600 14

Characteristic Group

Wavelength (cm -1)

Characteristic Group

water , O-H stretch aromatic C-H stretch - CH , stretch - CH , - stretch -CH , Carbonyl, C = 0 aromatic C = C stretch

1450cm-1 1375 1030 860 805 735 715

CH , rock - CH , rock S=O aromatic C-H rock aromatic C-C roc k aromatic C-H rock long chain , - CH , -

WATER

This decrease in aromatics is consistent with results of earlier workers (Smith and MacIntyre 1971 ; Boylan and Tr ipp 1971 ). Naphthenes , as well as being only very sparingly soluble , appear to be singularly inert to the other degrading agents , oxidation and microbiological.attack.

NaphtMn, cC.r_, 1c.,. o, c 1 11

(iv) Microbiological Attack During the course of the LMDO weathering trials , it was noticed that after 1-2 days a ' skin ' or ~e udo membrane appeared at the oil-water interface at which had collected particulate organic and inorganic detritus from the seawater as well as microparticulate insolubles from the diesel oil.

This interface took on a gelatinous emulsified appearance , characteristic of s rface active materials having lipophilic and hydrophilic properties . This appearance was consistent with microbial attack at the oil -water interface. Virtually all kinds of hydrocarbons are susceptible to microbial metabolism and oil oxidising bacteria are most abundant in coastal waters and mud . Such bacteria in well-oxygenated water might oxidise oil at rates from 0 .02-2 .0 g/m'/d at 20-30°C (Zobell 1969) . However, even at fhe highest rate the total amount of oil broken down in this way would only be about 4% of the original oil layer .

In general , alkanes are attacked more rapidly and support more microbial growth than either aroma -·.c or naphthen ic compounds , straight chain compounds being especially susceptible to bacterial attack. (v) Effect of Turbulence

Fig. 3. Variation of Aromatic and Naphthenic Carbon during Weathering of L.M .O.O.

(iii) Infra-Red Spectroscopy The wavelengths of bonds, etc . , found in oils are given in Table 2 (Mattson et al. (1970) ). The results of I-R analysis of the LM DO are plotted as ratios of peak heights of selected characteristic bands in Fig. 4. The increase in the ratio of the band at 1710 cm ·1 (carbonyl group) to the aromatic stretching band (1600 cm ·1) is a straight line passing through the origin. This indicates that progressive oxidation of the oil did occur. The negative slope of the 810/720 cm·1 ratio ' indicates a decrease in some aromatic groups (810 cm ·1) compared to the ubiquitous CH , groups (720 cm ·1) which is consistent with the results found from the n-d-M analysis.

The oxidation of the oil is most probably on the side chains of substituted aromatics.

Re-routing the normal water flow of about 10 1 /min through the tank via sprays above the tank caused vigorous turbulence in the oil layer . This flow rate was equivalent to an extreme storm situation and so was probably more representative of surf conditions .

Under these conditions the oil layer was broken up and dispersed within two days . The effluent, which previously was oil -free , contained up to 50 ppm of oil as droplets . Due to the enhanced surface area so formed , microbial metabol ism of the oil would also be more rapid. This demonstrates the importance of turbulence due to rain and splashing from wave action in dispersing oil in the sea proper .

Arbi t rary Sc al e

evapor.,tion

f Til!IC - days

810 / 720

Fig. 5. Relative Importance of Weathering Processes.

CONCLUSIONS (i) The Weathering Process Simulation of oil weathering suggests a qualitative description of the various contributing processes as depicted in Figure 5. Evaporation and dissolution are shown as first order decay processes with evaporation being the major effect. Photo-oxidation is shown as a linear process of minor effect. Microbial degradation has a lag time and then a slow rise as microbial populations build up to a limiting value at the oil-water interface . Turbulence would change the relative importance of the effects , with oil dispersion in fine droplets leading to much more rapid dissolution and bacterial attack.

l. 5

1710/ 1600

l.O

0 ,5

250

)00

lSO

Time l hn )

Fig. 4. IR Band Absorbance Ratios During Weathering.

WATER

(ii) Spill Identification Gas Chromatography provides the most detailed " finger print" of a specific oil giving the relative quantites of the carbon number fractions . Simulated weathering provides information on the rate of change of composition and this can be used to estimate the original composition of a weath ered oil or alternatively to estimate the timing of an oil spill event . In this context the weathering tank could be used to carry out further weathering of an oil spill sample (provided it is not too old) and with GC analysis provide information on the weathering decay constants for specific carbon number fractions.

15

Infra-red spectroscopy of oil is a usef ul back-up techniqu e, although the effect of oxidation needs to be accounted for when comparing different samp les. Alternat ively the t echnique can be used to assess the degree of oxidat ion and co nfirm the age of the sp ill samp le.

T he n-d -M analysis provides information of a d ifferent ki nd and enables characterisation of oi ls by the properties and specific types of the three main hydrocarbon compon ents , paraffins , naphthen es and aromatics. The technique has the advantage that simp le measuremen t s (viscosity, ref ract ive index and density) are al I that are required.

ACKNOWLEDGEMENTS We wish to acknow ledge th e ass istance of th e Maritim e Servi ces Board of New Sout h Wa les for provision of experi mental and analytica l fac il ities.

REFERENC ES Anon. , 1977 B.P. Envi ron mental Control Centre, London. Table published in '" Aust. Fisheries", 36 , No. 9 4-7.

ASTM o 3238-74 1974, Sta ndard Method of Test for Carbon Distribution and. st ructural Analysis of Pe trole um Oils by the n-d-M Method 'Annual Book of ASTM Stan dards part 25', ASTM, Philadelphia.

S. A. Berridge, R. A. Dean , R. G. Fellows and A. Fish 1968, The Properties of Pers istent Oils at Sea, Journal of Inst. Petro leum 54, No. 539, 300-309.

D. B. Boylan and B. W. Tripp 1971 , Determination of Hydrocarbons in Seawater Extrac ts of Cru de Oil and Cru de Oil Fractions, Nature 230, 44-47.

D. K. Butto n, 1971 , Petro leum - Biological Effects in the Marine Envi ronment , in D. W. Hodd (ed), " Impingement of Man on the Oceans", W iley I nterscience.

D. C. Gordon, Jr., P. D. Ke izer, W. R. Hard staff and D. G. Aldous 1976, Fate of Crude Oil Spill ed on Seawater Contained in Outdoor Tanks , Environmental Sc ience and Technology 10, No. 6, 580-585.

P. C. Lucas 1978, ' Marine Oil Poll ution: Th e Ef fec t of Weathering on the Compos iti on of Oil Slic ks and t heir Ident if ication ', M.App.Sci . Thesis , Unive rsity of New South Wales.

J. S. Mattson , H. B. Mark Jr. , A. L. Kolpack and C. E. Schutt 1970, A Rapid Nondestructive Tech nique for Infrared Identif ication of Crude Oils by Internal Reflect ion Spectroscopy, Analytical Chemistry, 42 , No. 2, February, 23 4-238.

H. 0. Sivad ier and P. G. Mkolaj 1973 , Measu rement of Evaporation Rates from Oil Slicks on the Open Sea. Factors Govern in g t he Fate of Oil at Sea. Joint Conference on Preve ntion and Control of Oil Spi lls, Washington D.C., Ame rican Petroleum In st itute pp 475-484.

C. L. Smith and W. G. MacIn tyre 1971 , Init ial Aging of Fuel Oil Films on Sea Water, Proceedi ngs of Joint Co nference on Prevention and Co ntrol of Oil Spi lls, American Petroleum Institute, Un ited Stal es Federal Water Pollution Control Autho rity , U.S. Coast Guard , Was hington D.C. pp 457-461 .

J. Ward ley-Smi th (Ed.) 1976, " The Con t rol of Oil Polluti on ", Graham and Trotman Ltd .

C. E. Zobell. 1969 , Proceedings of Joint Conference on Preven tion and Control of Oil Sp il ls, Ame rica n Petrole um Instit ut e and U.S. Federal Water Pollution Control Au thority, p 317.

APPENDIX. Methods of Analysis (i) Gas Chromatography A Hewlett-Packard 5711 temperature-programmed gas chromatograph was used as follows ; Col umn: 2 m stainless steel, 3.2 mm 0 .0 ., packed with 80-100 mesh Chromasorb G acid washed, dimethylchoros ilane treated , coated with 5 wt % OV101 Si licone oil.

Carrier Gas: Helium , 30 ml/min Temperature Programme: 80-320 deg. Cat 8 deg . C/min Detector: Hydrogen Flame Ionisation Sample Size: 1-5 micro litres.

Output to: Recorder (1 mv ful l scale); Integrator, H-P 3371 B. The oil samples or extracts , made up in ether or freon TF (b .pt 47 deg . C) as 5 w/v % sol utions, were injected into the G.C. by syringe .

(II) Infra-red Spectroscopy The IA-spectra were obtained from thi n fil ms pressed between two sodium ch loride plates on a Jasco model IRA-1 grating instrumen t. The oi ls were previously dried over anhydrous sodium sulphate.

ERRATA We apolog ise for the fo ll owing printers' errors in the paper , "ODOROUS COND ITIONS IN LAGOON S TREATING HIGH-SULPHATE WASTEWATER" by K. J .

Hartley ; Water, December, 1978.

1. The tenth line in Table 1 shou ld read Oxygen transfer rate at 2 mg / I D.O.-2 700 kg/d 2. The last four paragraphs of the section headed POSSIBLE CAUSES , "No oxygen is formed ... . ...... .. .. . .. . ......... . in facu ltat ive lagoons" , should fo llow the end of the section headed SULPHUR BACTERIA .

3. The first chemica l equation on page 9 shou ld read 2so; + organics 2s= + 4CO + 3H 0 + organics .

2 2

16

8th FEDERAL AWWA CONVENTION 12 • 16 November 1979 -

GOLD COAST QUEENSLAND

HARRY BUTLER to be GUEST SPEAKER AT CONVENTION Harry Butl er, MBE, Conservation Consu ltant extraordinaire , has accepted our inv itat ion to be guest speaker at our Convention Dinner on Tu esday , 13th November, 1979. He has commended the - conference comm ittee on its choice of theme - " Water - the Indestructible Resource ", and w ill speak on this top ic, .but beware he could produce reptiles from the most un like ly places . Recent ly on a Michae l Parkinson Show on ABC T.V. , Mr Butler had a blue tongue l izard in his shirt during the in terview and later produced a 12 ft . diamond carpet snake to the horror of tHil interviewer.

Mr Butler is wel l known for his contribution to conservat ion aspects of nature and our natural resources inc luding water which is necessary for the preservation of life of al l types . He is t he author of the T.V. series " In The Wi ld" wh ich is enjoyed by viewers throughout Australia .

An enjoyab le and interesting evening , as part of the 8th Federal AWWA Convention, is ensured at the Convent ion Dinner , for al l those who attend.

Continued from Rankin and Milford Page 12 Further , for more detailed planni ng purposes , or for some scien tific studies , the prese nt mode ls could be improved cons iderab ly by (1) dividing the 7 day averaging periods into small er t ime intervals , (2) div iding the r ive r in to sma ller segments (3) calibrating the d ispe rsion characteristics in each individual segment for a number of tida l and stream flow situations , and (4) calibrating oth er parameters in detai l for th is specific river system .

Finally , it shou ld be noted that such simplified and one dimens ional models are inadequate for a thorough investigation of the hydrodyn amic and dispers ion characteristics of this irreg ular natural es tuary .

•

ACKNOW LEDGEMENTS The authors wo uld like to thank th e Water Qual ity Counci l of Queensland for providing assistance and helpful inform ation , and a number of indi v idu als who he lped with th is work : Professor Ed Ho lley, Dr. John Stee le, Mr . John Church , Mr. George Cain , Mr. Bil l Grove, Mr . Clyde Croskell , Mr .

Dav id Johnston, and Mrs . Dahna Dearden. This paper is based upon th e th es is "Sa linit y and Dissolved Oxy gen Inves tigations and Simulat ion in the Brisbane River " submitted by R. 0 . Rankin to th e Department of Ph ys ics of the Uni vers ity of Qu ee ns land for the Master of Science Degree .

RE FERENCES Bella, D. A. and Grenney, W. J ., 1970. Finite Difference Convection Errors. J. of the Sanitary Engineering Division , ASCE , Vol. 96 , No. SA6, pp.1361 -1375.

Cain, G., 1975. (University of Queensland postgraduate research , unpublished.)

Dailey , J. E. and Harleman , D. R. F., 1972. Numerical Model for the Prediction of Transient Water Quality in Estuary Networks . ·Report No. 158, R. M. Parso ns Laboratory for Wate r Resources and Hydrodynamics.

Fei g ner, K. 0 . and Harris , H. S., 1970. F.W.Q.A. Dynamic Estuary Mod el.

Documentation Report , Environmental Protection Agency , Washingt o n D.C. Hinwood, J. B. and Wall is, I. G., 1975. Review of Models of Tidal Water s. J. of Hydraulics Divisi on, ASCE , Vo l. 101 , No. HY11 , pp. 1405-1421 .

Milford , S. N. and Church , J . A., 1977. Simplified Circulation and Mixing Model s of Moreto n Bay, Queensland . Aust. J. Marine & Freshwater Res., Vo l. 28 , pp.23-3 4.

Shen , H. W., 1971 . River Mechanic s. H. W. Shen. U.S.A .. Chapter 26 .

Shubinski , A. P., McCarthy , J. C., and Lindorf , M. A. , 1965 . Comput er Simulation of Estuarial Networks . J . of Hydrauli cs Divi sion, ASCE . Vo l. 91 , No. H7 5, pp.33- 49.

WAT ER

l'

USE OF SERVICE RESERVOIRS TO MEET WATER SUPPLY PEAKS

By G. Cossins The service reservoirs of an urban wat er supply system have the dual role of providing diurnal balancing storage to meet the peak hour demands from th e consumers and also of providing a re serve supply to cover emergencies .

The diurnal storage variation is usually about one quarter of the total daily demand . On the other hand the amount of reserve storage prov ided depends on t he aff luence of t he comm un ity and is frequently made eq ual to one peak day 's demand .

There is always a temptation to cut into the reserve storage as a device to meet consumer demands in peak periods whilst deferring the amp lification of the bu lk supply system (treatment plant and trunk mains) . The main problem is to decide how far this process may be safely extended .

The matter can , fina l ly , be resolved only on a probability basis and req uires an analysis of the statistical d istribution of the daily demands from the consumers . As the demand for water rises cont inuously in most systems the analysis is carried out on the ratio (a} of each daily demand to the trend va lue of the average day demand (A} fo r t he year under cons ideration .

For this purpose it is necessary to assume a smooth trend of the average annual daily consumption to allow for all the variations in annual consump tions due to cl imatic factors. A computer ana lysis is then made of the probability of exceedence for single day demands a,, for the average of two succ essive days a,, for the average of three successive days a,, etc. up to the, average of ten or more successive days as required . The probab il it ies for the Brisbane demands over a fo urteen year period are shown on Figure 1.

From Fig . 1 it will be noted that the probability of ratios exceeding 1 .42 for sing le day demand is very low i .e. 0.1 % or 1 in a 1000. However , Brisbane has experienced ratios of 1.5 on two successive days .

For the remainder of the analysis it will be necessary to adopt a standard probabi lity of exceedence . In the Brisbane case a probab il ity of 0.1 % has been chosen which means that the adopted ratios could be exceeded on an average once in about 1000 days , or Geoff Coss ins is the Investigating Engin eer of the Departm ent of Water Supply and Sewerage of the Bris bane City Co unc il. His work comprises the fo rward planning of every aspect of the Brisbane wa ter suppl y and he is th e author of numerous papers on the subject .

WATER

three years . Much longer records would be necessary to extend the above analysis but , for Brisbane , the ratios rise very slowly and on ly a sma ll error wo uld be involved in any extrapolation .

An individua l analys is has to be made for each water supply investigated.

Then , over any period of n days , storage drawd_ own = total consumer demand less total bu lk system de live ry, i .e. Dn = n(anA- C) = n(anA - RA) = nA(an-R) (Eq n. 1.) and D, = 1A(a, - R) D, = 2A (a, - R) D, = 3A(a, - R)

Let a, , a, , a, etc. be the ratios of the actua l dai ly consumption to the trend day cons umption at a given probabi lity of exceedance ( in the Brisbane case 0.1 % ) for one peak day , two successive peak days , three successive peak days etc .

The rest of the procedure is illu strated by an exercise on the Brisbane system . (Th is exercise wil l be revised in the light of subsequent forecasts so that conclusions will serve on ly as an illustration of the method.)

In 1982-83 , the trend va lue of average daily cons umpt ion (A} was forecast to be 700 ML per day, w hil st t he peak capacity of the bu lk supp ly system (C) was expected to be 900 M Li day and the total service reservo ir storage capacity (T) was expected to be 1168 ML .

900 Then for 1982-83, R = = 1 .29

Then Let R=C/A C = peak day capacity of the bulk supply system (treatment plants , pump ing stations , trunk mains) A = trend value of average day demand for year under considerat ion D,, D, , D, def ic iency in service reservoir storages for one peak day, two successive peak days, etc . n = number of successive days

700

In a peak demand period of several day's duration the demand will vary from day to day giving one peak day, two successive days of highest average demand etc. etc.

The storage def icienc y fo r each of t hese co nd iti ons is ca lcu lated unt i l a maximum storage def iciency is reached as in Table 1. Th is shows that the max imum loss from tre service reservoirs , at a probability of exceedance of

In a h igh demand period the serv ice reservoirs of a system w ill co ntin ue to lose storage as long as demand exceeds the capacity of the bulk supply system to deliver water to the service reservoirs .

...... -:.

l4

V, _,:..---_-

p ~/

l3

./.,, . .,.

~

1-2

/.

,.,

,I ~

0·9 0·8

0·7

--·

_k;:::

..,..,.

_.,......- v

--~

V

~

~

~

/

/

/

~

/

~

/

1 Day

-

---2 Day Ave -·-5 Day Ave -

99·9 99 95 90 80 50 20 10 5 1 0·1 PROBABILITY OF EXCEEDANCE % Fig. 1.

Exceedance ProbabilitiesBrisbane Water Supply 17

0.1%, wou ld be 196 ML from the four successive highest days and the service reservo irs would have lost 17 % of the storage capacity.

The process is repeated for different years using the predicted growth curves . After some experience the calculations can be shortened by observing that the trend of n(an - R) quickly reaches a max imum value. The max imum va lues of storage loss for each of the trials ?re co ll ected and tabulated in Tab le 2, and shown graphically in Fig. 2.

period on record , i.e. , November 1969.

This was analysed in the same way bearing in m in d that every individual high demand period has its own charac teristic an values. The results are also plotted on Fig. 2. This shows that 52% of the service reservoir storage would have been lost in the November 1969 period with R = 1.25 . However, with R reduced to only 1.22 the loss wou ld have risen to 95%.

Although the Novembe r 1969 demand period was a rare event it c learly indicates, in the case of the Brisbane supp ly , that it would not be wise to operate w ith R be low 1.25. At an 0.1 % probability of exceedance , the service reservoir loss wou ld have been 30%. On to this must be added the 25% diurnal variation . These quant iti es are not simply additive .

Although a definite example was worked , Table 2/Figure 2 are almost dimensionless and depend only on the probabi l ity spect rum of the Brisbane consumption. It can also be shown that D/T is much less sensitive to T than it is to R. This shows that capita l expenditure on treatment plant amplification is much more effect ive for meeting system peak demands than the alternative of increasing service reservoir capacity .

This analysis assumes that each service reservoir can be supp li ed at al I times with its due proportion of water , w hich is unlikely in pract ice .

If it is intended , for instance, to rely on the drawdown of service reservoirs as a means of deferring treatment plant amp li ficat ion , it wi ll first be necessary to amp lif y trunk and distribution ma ins to ensure the even distribution of water to the service reservoirs .

The overa ll conclusion of the study is that , for the Brisbane Water Supply System at least, the capacity of bulk

TABLE 1

1982-83 A = 700 , C = 900 , R = 900 = 1 . 29 , T = 11 68 700

n

a

1 2 3 4 5 6 7 8

a1 a2 a3 a4 a5

an-R n(an-R)

an

0. 13 0 .11 0.09 0.07 0.05 0.04 0.03 0.02 0 .01

1.42 1.40 1.38 1.36 1.34 86 1.33 87 1.32 as 1.31 a9 1.30

!)

D= nA(an-R )

0.13 0.22 0.27 0 .28 0.25 0.24 0.21 0.16 0.09

0 /T

91 Ml 154 189 196 175 168 147 112 63

8% 13 16 17 15 14 13 10 5

TABLE 2 Year 1979-80 1980-81 1981 -82 1982-83 1983-84 1984-85 1985-86 1986-87

R

n

1 .41 1 .36 1.32 1.29 1.25 1.22 1.19 1.17

1 2 3 4 7 9 10 11

an- R n(a~·R) 0 /T U.01 0.04 0.06 0.07 0.07 0.08 0.10 0.11

0.01 0.08 0.18 0.28 0.49 0.72 1.00 1. 21

0.6 % 4.9 10.9 17 .0 29.7 43.6 61.0 73.3

A study of the above data shows that the percentage loss in service reservoir capacity D/T increases rapid ly as the ratio of the peak day capacity of the bulk supp ly system to the trend value of the average day demand (R) decreases .

The prob·lem st ill rema ins to place a limit on these ratios for practical operation .

In the Brisbane case an indication can be given by the highest demand

--

1-5 C

cu c

"(

. . . ___

I)

1-1

v n .___ ______ 1969

·.

,,

~ 12 . RV 0

'---f!.o_ v

an

~"~------- ·--.:.:· -"-----R -=--· / 19 6 D/ {s ~-~~~-;;_~=--:_-___~-

1-4 "'

-01-3

-......,,_

T

01

V

- ~ : --:.

~ T

= 1-5 ~ s = 2· D

5

1

2

3

4

10

20

30

40

----

n

5

Fig. 2 18

g

7

8

60 70 o/o

80

6

9 90 100

water supply system shou ld not be less than 1 .25 times the trend value of the average annua l daily ~ nsumption.

The procedure can be further generalised as follows : Lets = Totalservicereservoirstorage (T) Average trend day demand (A) Dividing equation 1 by T we get: Dn

T

= nA(an - R) = .D. (an _ R) AS S

Ranges can be assumed for both R and S independently of any actua l examp le. The so lution will then depend on the characteristics of the particu lar water supp ly system u11der exam in ation expressed in terms of an versus n. The genera li sed results can then be used to exa mine the consequences of ampl ifying the peak day capacity of the bu lk supply system (C) and the total service reservoir capacity (T) to meet any pro jected trend va lue of the average day co nsumption (A) for the water supp ly syste m . A range of S va lues is plotted on Fig . 2. The Brisbane system operates w ith Sin the range from 1.5 to 1.7 .

Figure 2 can be used to eva luat e the economics of meeting peak day demands in a water supply system by the alt ernat ive methods of amp li fy ing the bu lk supp ly system and of amp lification of the service reservo ir storage. If a nomina l li mit of 30% is adopted for D/T in the Brisbane system , a doubl ing of service reservoir storage from S = 1.5 to S = 3.0 wo uld decrease R from 1.26 to 1.20, i .e. by 5%.

In other words , a doub lin g of the serv ice reservoir storage wou ld be as effective as a 5% in crease in the capacity of the bulk supp ly system in meeting peak i'eriod demand . In the Brisbane system the doubling of serv ice reservoir capacity wou ld cost about $16 mi ll ion aga in st $4 million for a 5% increase in the capac ity of the bulk supp ly sysiem. In the Brisbane case the amp lifi cation of the bulk supp ly system is c learly the more economical way of meeting peak consumer demands. Depending on the relative econom ics of the different components this rule wi l l probably prevai l in the majority of urban water supp ly systems.

The main conc lusions of this study are , firstly , that , for the Brisbane water supp ly system, the risk of emptying serv ice reservoirs during periods of peak demand rises rapidly for values of R be low 1 .25 and th is suggests a practica l lower limit to the ratio of the capacity of the bu lk supply system to the trend va l ue of the average day demand. The second conclus ion is that ampl ifi cat ion of the· bulk supply system is a more economica l method of meeting system peak demands than ampl if ying service reservoir capacity.

WATER

SULPHIDE CONTROL WITH OXYGEN Mount Bassett Rising Main, Mackay, Queensland

by D. C. Hutchings Summary

A long -standing odour problem caused by anaerobic conditions in a rising main serving the City of Mackay, Queensland , has been so lved by oxygen injection. The problem was at its worst at the Mt. Bassett treatment works, where the rising main discharges all sewage from the City of Mackay.

Oxygenation of the main also im proved conditions at Mt .

Bassett , w ith reduced odours around the wo rks and a reduction in the load on the digesters.

The aim of the Mackay City Counc il was purely one of overcoming the odour problem , and only sufficient oxygen is being inj ected to inhibit the formation of sulphides in the main. However it is possible that further tests using add itional oxygen to ach ieve " in -main " treatment may be carr ied out at a later date .

OXYGENATION OF MT BAS!:,FTl FUSl~G MAIN

Fig. 1. Total sulphide levels in the Mackay City rising main during oxygen injection trials. At an injection rate of 180m 3/ day (34 mg/litre), levels were generally below 0.8 ppm and odours along Harbour Road were eliminated.

Ri ve r for one kilometre north of the river . This length of main exposed to the sun aggravates the existi ng anaerobic condit ions , particularly in the summer months.

Prior to 1973 when aerat ion was adopted , detention ti mes were as high as seven hours . Sulph id e levels measured at Mt . Bassett were regular ly around 5 ppm (and averaged in excess of 3 ppm) and caused extremely offensive odours.

These were part icu lar ly noticeable to motorists travelling on Harbour Road which join s the city to Northern urban areas in Pioneer Shire and passes close to the treatment works.

Air injection: In 1972 Counci l took steps to introduce air inj ect ion at four location s along the main (which incidentally does not rise along its full length) , using electric-motor driven compres sors in sound -proof enclosures . For various reasons (proximity of th e air valves to a hospita l and other premises) some of th e best sites for in jection could not be used. While air inj ection did ach ieve a red uct ion in sulphide leve ls to an averag e gen erally between 1.8 and 2.0 ppm (as measured just prior to , and after the oxygenation trials in 1977) it never eff ectively eliminated odours along Harbour Road , and caused a number of d iff icu lti es at the pumping stat ion and treatm ent works .

Since the air did not fully dissolve, surging occurred, causing sp lashing at the inl et into the treatment works and maloperation of the raked screens. An alteration to the pump inlet and a time clock contro lling the screen rake helped, but it was found that screenings , grit and rags were being carried into the primary s lu dge, thus endangering the digestors.

Recently 70 m 3 of sand was removed from one digester.

Also, grease and other solids were flotated as a 120 mm thick scum, causing odour and fly nuisance . One air injection

Odour problem : The Mackay City Council had exper ienced odour problems from the Mt . Bassett rising main ever since it was com missioned in 1968. Prior to 1968 sewage treatment consisted of a pumped main to holding tanks at the mouth of the nearby Pioneer River where the sewage was discharged on the outgoing t id e. In 1967 the prese nt Mt. Bassett treatment plant was estab lish ed North of the town across the Pioneer River and one kilometre inside the Pioneer Shire. The treatment works is owned and operated by Mackay Counci I but also treats sewage from Pioneer Shire on a pro-rata cost basis. Current plant at Mt. Bassett comprises: screening , primary sedime ntatio n , two biological filters in parallel , clarifier , sludg e digesters , and sludg e and humus drying beds. Work is current ly und erway on a new primary sedimentation tank and an extended aerat ion facility whic h w ill increase the work 's capacity from 35 ,000 equivalent population to 55 ,000. ¡ The rising main is 0.6m diameter and runs 4.8 km from the centre of Mackay (from the Sydney Street pump ing station) to Mt. Bassett. When the Sydney Street pumping stat ion was commiss ioned in 1968 this made it practicable to drain the city to that point and current ly some 120 km of sewerage mains terminate t here. The Sydney Street pumping stat ion and r isin g main thus handles the ent ire sewage emanating from the Mackay City Council area . The rising main runs under the city , but is exposed where it crosses the Pioneer David Hutchings is Business Development Manager of the Enviroshield Group cf Commonwealth Industrial Gases.

Ltd. WATER

Fig. 2. One of the pumps at the Sydney Street pumping station . Note oxygen injection point tube to discharge side of pump.

19

point immediately after the pumping station had to be closed because it created surges which affected the reflux valves on the pumps, eventually causing one valve to fail.

These problems persisted until 1977 when the Mackay Council undertook trials with oxyge n, carr ied out by engin ~ ,eers of the Co uncil and CIG 's Enviroshield Group , from 20th September to 5th November .

Oxygen trials:

Trials with oxygen injection at Sydney Street pumping stat ion were made through a single 12 mm d iam eter copper pipe on the discharge side of each pump. The results are shown in Fig . 1 (this was drawn up by the Council 's Engineer Mr John Martin to enable the odour problem to be quantified in terms of su lphid e leve ls) . By injecting oxygen at the rate of 34 mg/litre, su lphid es at Mt . Bassett were reduced to an average of 0.8 ppm , which is the cr iti ca l level above which odours become noticeable on Harbour Road .

During the trials oxy gen injection rates were increased to ascertain the potential for "i n-main " treatment . Unfort-1nately at that time an air valve in the main was acc id entally left open , allowin g oxygen to escape, (see Fig . 1).

By the time the va lve was closed there was insufficient time to conc lud e the test. However the testing that was undertaken does . confirm that more slud ge is produced at Mt. Bassett and that a greater percentage of so li ds sett le out in the primary sed im entation tank.

Costs:

Oxygen costs were offset through elimination of the air compressors for air injection , and a 3½% power saving through improved pumping efficiency when oxygen was in jected , (i.e. due to the greater solubility of oxygen as against air injection when undissolved gases - mainly nitrogen formed a layer above the sewage thus effective ly reducing pipe diameter). The estimated total net cost of oxygenation per year worked out to a 2% increase in the Council's pedestal rate which is based on 9500 pedestals.

This was subsequently accepted by Council and in February 1978 a permanent CIG Enviroshield oxygen treatment facility was commissioned.

Permanent oxygen installation:

Fig. 3, taken at the Sydney Street pumping stat ion , shows the permanent bulk li quid oxygen storage vesse l (a VIE 15000 containing the equivalent of 11 ,450m 3 of gaseous oxygen).

The station has two radial flow pumps which hand le an average daily dry weather flow of 7 ML at the rate of 1 ML/hr through the 0.6m diameter rising main to Mt. Bassett .

Fig. 2 shows one of the oxy gen injection points on a pump .

In place of the copper pipe used during the trials , oxygen is now injected through a diffuser wh ich reduces the oxygen to a fine bubble size and has increased solubility such that an increased head of 50 kPa is now obtainable from the pumps.

Oxygen injection is controlled by a critical metering system wh ich is regulated by a time clock set for separate day and night injection rates. The injection system is ent irely automatic and is initiated by the pumps ' starting circuits. The average pumping cycle during dry weather flow is 8 minutes; however an automatic timer cuts out oxygen injection after 10 minutes pumping - on the assumption that the pumps are running continuously as would only happen in the event of a control fault, or heavy seasonal influ x of stormwater.

This cuto ut economises on oxygen during periods when the sewage would be heavily diluted and when detention time in the main (as a result of cont inuous pumping) wou ld reduce to 2½ hours.

The permanent oxygen installation was orginally set for a maximum night-time injection between 10 p.m . and 6 a.m.

However as a resu lt of further experimentation, maximum injection was switched to the more intense mid -day pumping period between 11 a .m . and 2 p.m. Allowing for the 4½ hours detention time, this cons iderabl y increases the dissolved 20

l Fig. 3. View of the Sydney Street pumping station showing the oxygen storage vessel.

oxygen co ntent in the sewage at the time it exits at the Mt. Bassett treatm ent works between th e hours of 5 p.m . and 8 p.m. (previously th e worst time for odou rs on Harbour Road).

It is of interest that Mackay is 100 % sewered. Future deve lopments and rezoning are only expected to increase the ultimate population to around 45 ,000 which would reduce the detention time to two hours . The present oxygen installation wi ll ensure that sulphide levels can be held to th ei r present low levels and odours el iminated . It can also be used at any time at hi gher injection levels to achieve "inmain " treatment .

NORTHERN TERRITORY PUBLIC SERVICE DEPARTMENT OF TRANSPORT AND WORKS

Northern Territory Government, Department of Transport and Works has a vacancy for a senior execut ive on its Management Board .

DIRECTOR OF WATER

$30,000 The Job Manage the operations of fhe Water Division in the Northern Territory responsible for (a) water resource activities, and (b) pub lic water supply and sewerage faci lities.

The Person Proven executive experience in water resources development and the water supply and sewerage field . Relevant professional qualifications and extensive experience are desirable, but prime consideration wi ll be given to personal qualities and abi l ities.

Conditions of Service • six weeks recreation leave per year; • subsidised recreation leave air fares to any Australian capital city every two years for the employee and dependants; • salary will be negotiated in the vic inity of $30,000 ; • generous sick leave and long service leave entitlements; • the Government current ly operates an assisted housing scheme within the Territory .and app licants' requirement s will be di scussed at interview.

Applications close with: Director of Administration Department of Transport and Works P.O. Box 2520 DARWIN, N.T . 5794 by no later than 6th July 1979.

WATER

EIGHTH FEDERAL AWWA CONVENTION THEME: WATER - THE INDESTRUCTIBLE RESOURCE 12th to 16th NOV EM BER 1979 - Conference Secretary - Allan Pettigrew, P.O. Box 129, Brisbane Markets 4106. ' GOLD COAST Telephone : (07) 200-1176 QUEENSLAND Technical Displays - Leo Roessler (07) 52-8866.

Telex: AA 42129

PROGRAMME SUNDAY

3.00 6.00 - 7 .30

Registration Desk opens Pre-co nference in forma l get-together Drinks and hors d'oevres

(TENTATIVE)

...

WEDNESDAY Inspection tours, Morning and After-

noon w ith barbeque lunch Free evening

MONDAY

10.00-11.30 Balance of Day 6.00 - 9.00

Official opening followed by keynote addr.ess · Technical Sessions

THURSDAY

Morning Afternoon

Barbeque by Canal

NOTE: Bus orientation tours of Go ld Coast on Sunday afternoon and Monday morning .

TUESDAY

Morning Afternoon Evening 6.00 - 9.00

Technical Sessions Evening choice of three venues (Restaurants) Block Book in gs at each e.g. a. Revue b. Exotic c. Forma l

Technical Sessions Technical Sessions FRIDAY

Official Conference Dinner with Guest Speaker

Morning Lunch

Technical Session Official c lo sing lunch eon by poolside .

EIGHTH FEDERAL AWWA CONVENTION 12th to 16th NOVEMBER, 1979 GOLD COAST QUEENSLAND AND

MUNICIPAL ENGINEERS WATER & WASTEWATER WORKSHOP [Contact: Ross Anderson, Cl- Tweed Shire Council, P. 0. Box 816, Murwillumbah, N. S. W. 2484. Tel.: [066] 72-2444.

17th & 18th NOVEMBER, 1979 TWEED HEADS, NEW SOUTH WALES Stay the whole week, attend both the Convention and the Workshop.

WATER

21

CONFERENCE CALENDAR 18th-21st May , 1979.

Annual Conference , Australian Society of Limnology , Tallangatta, Victoria .

24th May, 1979. ' Energy and Water - The Long View', Royal Society Building, Melbourne , 2.30 to 8.30 p .m ., organised by the Victorian Branch . Enquiries : Mr . R. Povey 741-4171 (W) .

12th July , 1979 Symposium on Aerobic Processes in Wastewater Treatment . The symposium wil I deal with some of the processes which have recently become available for the treatment of municipal and industrial wastewaters . Cost : $30.

Symposium papers alone $12.

Enquiries : Dr. David Barnes, School of Civil Engineering , The University of New Sou t h Wales , P.O . Box 1, Kensington , N.S .W . 2033 .

16th-20th July, 1979. " The Life in Time of Lakes", Freshwater Biological Association, Jubilee Symposium, University of Lancaster , England . Enquiries : Dr . T . B. Bagenal , Windermere Laboratories , F.B.A., .

Ambleside, Cumbria, LA 22, OLP, England.

26th -31st August, 1979. " Evolving Ecosystems " , Fourth International Symposium on Environmental Biochemistry, Canberra . Enquiries : The Conference Secretary, Australia Academy of Science , P.O. Box 783 , Canberra City, A .C.T ., 2601 .

27th -31st August, 1979. " Role of Water in Urban Ecology ", Amsterdam , Holland .

Enquiries : Mr . K . C. Plaxton, Secretary, Organising Committee, P.O. Box 330, Amsterdam , Netherlands .

17th-18th November, 1979 Loca l Government Engineers Association Northern Rivers Group , Munic ipal Water & Wastewater Workshop , 17th and 18th November, 1979, Tweed Heads, N .S.W . Enquiries : Ross Anderson, Tweed Shire Council, P.O. Box 816 , Murwillumbah, N.S.W . 2484 .

Tel. : (066) 72-2444 .

4th-8th February, 1980. " Water for the 1980's?" , A .W .W .A. Summer School, Adelaide. Enquiries : Dr . J . Cugley, State Water Laboratories, Private Bag P.O. Salisbury , South Australia , 5108.

23rd-27 June, 1980.

10th International Conference, International Association on Water Pollution Research, Toronto, Canada. Enquiries: Secretary-Treasurer , I.A .W.P.R ., Chichester House , 278 High Holborn , London WC1 , U .K .

22

Mr Willcock is Commercial Director of Kelly & Lewis Pumps.

7th-16th July, 1980 Special Course on Municipal Wastewater Treatment . An 8-day special course on "Municipal Wastewater Treatment" is offered by the Water Engineering Department of the School of Civi l Engineering at The University of New South Wales. The course is intended for qualified engineers in Local Government , or other authorities concerned with the design or operation of Municipal wastewater treatment works . This course will be similar to those held in January 1978 and July 1979. Enquiries: Mr. P. J . Bliss, School of Civil Engineering, P.O . Box 1, Kensington , N .S.W . 2033 . Phone : 6623015 (direct) , 662-3023 (messages).

Mr. Albert Angus has been appointed Deputy General Manager of Mather & Platt Ply. Ltd .

WORK PRACTICE CODE FOR AC PIPES

22nd-26th October, 1979.

International Symposium on Athal assic (Inland) Salt Lakes, University of Adelaide, South Australia. Enquiries : Professor W . D. Williams , Department of Zoology, University of Adelaide , Adelaide, South Australia, 5001 .

12th-16th November, 1979.

Eighth Federal A .W .W .A. Convention, Gold Coast , 1979. Theme - Water The Ind estructible Resource . Water, Sun, Surf , Beaches, Meter Maids , Friendly Hospitality, Entertainment, Wide Choice of Accommodation, Preprinted Papers , To urs and Inspections .

Enquiries: Convention Secretary, P.O. Box 129, Brisbane Markets , Queensland , 4106 .

Mr. K. J. Willcock New APMA President

Mr. Michael Burleigh has been appointed Manager, Laboratory Products Division, Watson Victor Limited.

A booklet detailing recommended work practices for t he handling and use of asbestos cement pipes is now available from the South Pacific Asbestos Association , 3rd floor , 129 York Street , Sydney, 2000 .

The booklet has been prepared by the Association to alert users of asbestos cement pipes to the potential dangers of inha ling excessive concentrations of asbestos dust , and recommend methods aimed at avoiding any risk to health.

It details simple-to -follow procedures developed to ensure that the amount of dust released when these operations are carried out remains well within the accepted safe levels for a lifetime of occupational exposure.

WATER

PUMPS FOR SUGARLOAF RESERVOIR PROJECT Ke lly & Lewis Pumps' invo lvement in Me lbourne's ¡Sugarloaf project . has grown further with the winn ing of contracts for the supp ly of three 1000/1200 mm SDS-DV horizontal split case pumps and baseplates.

The d iv isio n of Mat her & Platt Pt y.

Ltd . and member of the Wormald International gro up of companies has already supp lied several huge vert ica l pumps to the Yering Gorge pumping station; wi th t hese pu mps, probab ly t he largest of their type in the world, pushi ng 1000 megal itres of water per day from the Yarra and the Maroondah Aqueduct through a rising ma in to the reservo ir.

Now Kelly & Lewis pumps are insta lled at t he very heart of the complex to push 675 megal itres a day at varying rates through a pumping main to the in let of the treatment plant, the water being fed to the pumping stat ion from the reservoir t hroug h a scree ned 'draw off structure , transfer tunne l and suction main.

The three variab le speed pumps are instal led in the concrete encased steel framed pump hall , w ith motor co ntro l equipment in an annexe bay, each rated at 2.6 ki lol it res/seco nd un der all head conditions .

Al l three double suction, horizonta l, centrifuga l type pumps wi ll be direct coupled to a variable speed 11 kV wo und rotor motor, wh il e c losed air circuits will be used to reduce noise and permit water cool in g of motors via an air-water exchanger.

The motor speed range wi ll be geared so that pumping outputs can be varied in a stepless manner to suit reservoir

EDUCATION FOR THE WATER RESOURCE INDUSTRY The Me lbourne and Metropolitan Board of Works is carry in g out, on Austra lian Water behalf of the Resources Council , a st udy wh ich w il l examine t he manpower needs of t he urban water resource industry. The study wi ll identify factors affect in g t he industry's workforce over the next decade and beyond, wit h part icu lar reference to educat iona l needs. The study is concerned with water supply , sewerage and drai nage for the maj or urban population centres in Australia .

Over this period , a vari ety of factors may change the needs of the industry in terms of bot h numbers and t he types of skills required . The rate of econom ic growth w il l influence industria l water needs as wel l as the domestic demand ; a high rate of growth and climb ing standards of l ivin g wo ul d see more dwellings built, and more homes equ ipped with dishwas hers, automat ic washing mach ines and other waterconsuming devices. Socia l factors whi ch must be cons idered inc lu de t he slowing rate of popu lation growth as we ll as in creasi ng demands for a WATER

One of three large Kelly & Lewis horizontal split case pumps for the M.M.B.W. Sugarloaf Reservoir pumping station being drilled on the suction flange on a horizontal borer. leve ls and the requirements of the treatment plant, the motor speed control to be achieved with static Sc herbius sl ip recovery equipment whi le power factor correction capacitors w il l be insta lled to limit the power factor to 0.8 minimum .

Under normal operating conditions the pumping station will be unattended (w ith t he exception of an attendant on day sh ift) and will be controlled from shorter working week , a lower retirement age, and increased employment opportunities throughout the creation of more part-time and temporary positions . Political factors , suc h as the acceptabi li ty of demand management , wil l play their part , as will changes in techno logy; for example , increas ing ly acceptable " bio logical " self-contained toilets could revolutionise t he sewerage industry. The next decade or two is also like ly to see inc reas in g concern for the recycling of sewage wastes , as well as more attention to environmental issues such as t he m ul t iple use of urban watercourses , and the protection and use of gro un dwater reserves . Industry expenditure may see a shift from capital works to recurrent activity , and manpower needs w il l be affected by the changes that would follow.

Submissions are invited from anyone wishing to contribute ideas about these matters in so far as they will affect the industry's workforce , or highlight specific educat ional needs. Subm issions or inquiries should be directed to Mr. B. E. Lloyd , Senior Exec ut ive Eng ineer, Me lbourne and Metropolitan Board of Works, 625 Litt le Collins Street , Melbourne, 3000.

the treatment plant by the contro l room operator.

An auto matic prog ramming system w ill be used to start and stop pumps if the speed of any pump can not be ad j usted , though pump speed control will be automatic with provision for manual override .

The speeds of each pump will also be biased by means of pre-set ana log devices to compensate for different suction and deli very prpe head losses.

NEW BALL VALVE FOR PLASTIC PIPING SYSTEMS Mono Pumps (Austra li a) Pty . Ltd . has released a F. I. P. PVC bal I valve to suit most plastic piping systems . As a resu lt of its range of interchangeable connections, it can be connected to metric , inch-threaded , inch plain and other pipe systems.

The va lve is ava il ab le with PTFE or graphite po lyethy lene ball-seats . Connection is either by solvent welding, threading , f langes , unions or fi l letwelding .

The valve body can be d isconnected from the system easily and withdrawn laterally allow in g quick replace ment of both body 0 -rings and bal l seats . The use of socket 0-rings inserted between valve connect ions and bal l seats soften the movement and reduce efforts in operating t he valve. Because of t heir compactness and small overal l dimensions the new ball va lves are extreme ly l ight .

The valves wi ll fit pipes with an internal diameter of 3/8" to 4" , or 10 mm to 100 mm metric pipes . Weights range up to 6 kg2(just over 13 lb) .

For further information: Mr. David Dawson, Austral ian Sales & Marketing Manager.

23

B.O.D. RESPIROMETER Arthur Brothers have recently released a new On-Line and Laboratory Respirometer. The measurement of oxygen consumption rates provides information about a biological process which can be used to control rate of aeration , return sludge, sludge wasting and F/M ratio.

This " inside " information can be directly applied to conserve energy, reduce operation costs and improve treatment efficiency.

The On-Line instrument has been field tested by U.S. E.P.A. They found the instrument reliable and successful.

Both On-Line and Laboratory instruments can be utili zed for the new Standard Methods test for oxygen consumption rates on activated sludge.

can be carried in every briefcase or in the pocket . Operation with one hand is an advantage when measurements are carried out in areas which are diff ic ult to reach . For long-term measurements in the laboratory , the appliance can be plugged in a stand and can be easily read from all positions .

With each contact closure from the water meter the pump makes one stroke and therefore propo lil ional chemical inj ect ion is obtained . The injection rate can be varied by changing the stroke length of the pump to increase or decrease the dosage rate accordingly.

With proper selection of the pump and meter combination an injection rate from O to 10 parts per million can be obtained by varying the stroke length.

This system, using the ProM inent Electromagnetic Pump , eliminates the variable speed DC drive systems that normally required for such are applications .

For further details contact ProMinent and Fluid Controls Pty . Ltd ., 70 Whiting Street, Artarmon , N.S.W. 2064 . Phone 438 3655 .

EUROVALVE

For further information , please contact : JOHN MORRIS PTY. LTD. , P.O. Box 80 , CHATSWOOD , N .S.W . 2067.

Telephone: 407-0206.

LIQUID CHLORINATION SYSTEM

For further information , please contact:JOHN MORRIS PTY. LTD ., P.O. Box 80 , CHATSWOOD , N.S .W . 2067 .

Telephone: 407-0206 .

DIGITAL THERMOMETER Ultrakust Thermophil Type 4010 for semi-co nductor probes, Type 4010-1 for semi-conductor probes and Type 4020 for thermocouple probes. Temperature ind icat ion is effected on a LCD plate (liquid crystal indicator) giving a perfect presentation of the digits even in sunlight . The LCD is protected by an impermeable UV filter against direct sun rays .

The LCD requires a minimum of current so that the 9V compact battery is able to operate for long periods without a change or recharge of battery being necessary .

The appliance is switc hed on and off by means of a push button so that unintended permanent operation is avoided. It is small and easy-to-use and

24

A Proportional Injection System available from ProMinent and Fluid Controls Pty. Ltd. is proving to be very successful, particularly for chlorination systems for township water supplies and/or coo ling circuits . The basic electromagnetic ProM inent Metering Pump is co nverted for external control via a contact head water meter which is mounted in the water line which can give from 1 pulse per 1 litre of flow to 1 pulse to 25 litres of flow, depending on the meter size.

This valve is widely used in Europe and has been accepted after extensive tests by the British National Water Council to comply with BS 5163 for waterworks valves .

The feature of Eurovalve that is particularly unique to Australia is the gate design. A resilient rubber coating allows for positive sealing at all points of the gate profile . Resilient sealing eliminates the need for a seating recess achieving a straight through bore with optimum flow characteristics.

The gate profile itself is the key to EUROVALVES' operation . The design reduces seating torque to far below that of comparable valves and seats uniformly , without wedging or scrubbing. Extensive tests show that a resilient gate is less susceptible to wear than a metal one.

The valve features a bronze wedge nut at the top of the gate. This coupling allows the gate independent movement from the spindle during opening and closing , achievirig a positive shut off even when ther gate is subject to line deflection .

The positive gate guiding action prevents premature seating and eliminates gate chatter . Service life is improved and installation is equally successful in hori zontal , vertical or inclined planes .

Spindle gland sealing is achieved by Chevron type gland packing . Adjustment of the packing is pressure activated and accommodates spindle movement and more importantly is ADJUSTABLE .

A major feature of Eurovalve is the ability to carry out servicing with a minimum of disruption to its function.

Maintenance to the gland packing can be carried out with the valve still in service .

The Eurovalve is certainly leading the way in mains water valve technology , its robust yet lightweight from spheroidal graphite body to its unique resilient gate profile .

The manufacturers in Australia , John Valves , are confident that Eurovalve will prove as successful here as it has in Europe and the U.K .

For further information contact : Mr. Rodney J_ohn (053) 39 1991.

WATER

PETTIGREW CONSULTANTS PTY. LTD.

METCARBON Pty Limited

Pollution Control & Water Treatment Engineers

ANTHRACITE filter media

P.O. Box 94 , Rocklea4106 Telephone 200-1176

ACTIVATED CARBON powered and granulated

44 Koornang Road , Scoresby 3179

DESALINATION EQUIPMENT

(gi

Telephone 763 8988

a.

BOBY ANALYTICAL LABORATORY SERVICES

vapour compression and multi-effect distillation

ZEOLITES iron and manganese removal

GARNET PO BOX 785 NORTH SYDNEY 2060 TELEX: 24076

3 EDEN ST, CROWS NEST 2065 PHONE: (02) 9290393

TOTAL CAPABILITY IN

CONTROL

In Mechanical, Process and Biological Engineering Mechanical Engineering

Process Engineering

Biological Engineering

Grit re mova l plant Scree nin g press and bagger unit Circular and rectangular sed ime nta ti on ta nk scrapers Sludge co nso li dation tank thicke ners, mi xin g tan k stirre rs Sludge dry in g bed mec hani ca l li fte rs Sand bed li fters Contra Shear rotary screens

The rmal and che mical slu dge conditio nin g plants TC Incin erato r for scree nings Multip le hearth, fluid ised bed , ro tary drum sludge in cin e rators Static grate incinerator Di sso lved air flotation Carbon rege ne rati on and absorption systems

Standardised acti vated slu dge plant for small popu lations of up to 20,000 perso ns Exte nd ed aeration plant, Aerob ic slu dge digesti on.

Diffu sed air activated sludge plant.

Au to matic co ntro l syste ms for activated slud ge pl ant

"- HAWKER SIDDELEY ENGINEERING PTY. LIMITED Incorporated in NSW

Head Olllce: 262-284 Heidelberg Rd .. Fairfield . Vic. 3078. Tel. 489 2511 Branches: Sydney • Brisbane • Perth • Au ckland Hawker Siddeley Group supplies electrical and me chanical equipment with world-wide sales and service .

Agent s for Hawker Siddeley Water Engineerin g Ltd . (Templewood Hawksley Activated Sludge .)

3560HSE

WATER

25

Watson Victor bring to Australia

TURBIDITY AND ABSORPTION MEASUREMENTS IN WATER * Raw Water

* Potable Water

* Industrial Water

.,

* Sewage Effluent

The provision of accurate, cont inuou s turbidity measurement and the determination of contaminating materials in suspension in various types of water is becoming increasingly important . Turbidity level is directly and indirectly the most significant parameter with respect to water quality.

The SIGRIST - Photometer not only satisfies such demands for turbidity , but allows measurements to be made on chemical products in solution either selectively or as total contamination. SIGRIST optical turbidity and absorption measurement is a technique with almost unlimited applications . For filter monitoring, c larity monitoring, measurement of dissolved organic substances, potable water treatment, residual ozone measurement in water and the monitoring of heavily contaminated or discoloured industrial water , the SIGRI ST Turbidity range of measuring in struments have capab ilit ies that suit these difficult measurements so that reliable . data can be co ll ected .

Let us hear of your special problems in any of these areas so that we can be particularly selective in recommending a suitable instrument that wi ll serve you r need.

SIGRI ST WATER MONITOR WJ-3128

26

WATER

world advances in r------------------------------, technology...

D D D D D D D D

D D D D D D D D D D D D D D D D

...we'd like to tell you about them

D D D D D D D

The new industrial Service from Watson Victor.

Watson Victor Ltd. represent over 20 international organisations, manufacturing a comprehensive and highly successful range of sophisticated products for industry in the pollution monitoring, chemical processing and physical testing areas.

D D D D D D

TiGk any product or service you are interested in and we will send a data kit by return mai l.

Sa les& Service:

~

~tI~Qh~slnYn~SIQPR ,....,..

Sydney 95 Eppi ng Road. North Ryde. N.SW 2113 Telephone 8886188 Te lex 21602 Adelaide 33 Grove Avenue, Marl eston, SA 5033 Telephone: 297 8666 Telex 82740 Melbourne 16 Palmer Court.

Mt Wave rley. Victoria. 3149 Telephone 5433888 Telex 31412 WAT ER

D

Perth 324 Charles Street. North Perth. WA 6006 Te lephone 3288022 Telex 92890 Brisbane893 Stanley Street. East Brisbane. Ol d.. 4169 Telephone 3914441 Telex 41048 Hoba·rt 47 Wellington Street I North Hobart Tas .. 7000 I Telephone 34 2255 Telex 58203

Absorptiometers Air Samplers Auto Analyzers Auto Coll imators Bitumen Product Testing Equipment Borescopes CHNO Analyzers . ~~~~:c~~ke Te sting

Color Monitors .

Concrete Test ing Apparatu s Continuous Analyzers Controlled Environmental Rooms Cutting, Grinding.

Mounting & Polishing Materials Digital Density Meters Dust Emission Monitors Du st Monitors Earth Measuring Apparatus Elemental Analyzers Environmental Samplers Fibre Optic Systems Fiel.d Density & Moisture Equipment Fl ammability Test Chambers Flex ible Borescopes Furnaces .

Laboratory/Industrial /Special Purpose Gas Chromatographs General Laboratory Equipment .

Geophysical Testing Eqwpment .

Grinders - Specimen Growth Benches Hardness Testers Heat Controlled Equipment . .

Hum1d1ty Monitoring SyS tems Humidity Sensing & Recording Equipment Hygrometers Industrial Furnaces Industrial Ovens Magnagage Thickness Meters Mag netometers

D D

D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D D

Material Evaluation Equipment Metallurgical Preparation Equipment Metallurg1cal Microscopes Meteorological Systems Mounting & Polishing Materials Nuclear Moisture Density Meters On-Line Density Meters . .

On-Line Monitors Penetrometers Person.al Air .

Sampling Equipment Plant Growth Cabinets Pluv1ographs Polishers - Specimen Porosimeters Profile Projectors Resistivity Meters Rock Mechanics Test Equipment Sample Splitters Seismographs Sling f>sychrometers Slope Meters Smoke Density Chambers S0 1 Samplers & Monitors Soil Classification Apparatus • Soil Testing Instruments Specific Ion Monitors Specimen Grinders & Polisher.,; Stereoscopic Microscopes Subsurface Investigation Equipment Superpressure Fittings Surface Area Analyzers Telemetry Equipment Thermohygrographs Total Carbon Monitors li · I li t C II naxia es e s Tube & Chamber Furnaces Turbidity Monitors .

Unconfined Compression Apparatus .

V1s1b11ity Morntors Visual Inspection SySte111 s

I I /

1 1 1

I

I 1 1 1

I I I

1

I I I I

1

i 1

I

I

i 1 1

I : 1

NAME

POSITION COMPANY ADflRESS POSTCODE

L--------------------------------~

27

An aeration sistemis only as good asthe fineness of its bubbles * * *

* * * * * * * * *

System estab lished since 1919, with many hu ndreds of plants install ed throug hout the wor ld.

Aeration tanks flexible in design up to 9 metres depth offering maximum use of avai lable area.

Fine bubbles of 2 mm diameter give high oxygen transfer efficiency.

Uniform mixing .

Simp le construct ion in uPVC and non-cor rodib le ma terials.

Diffusers tructible.

virtual ly

Drainage of necessary.

tanks

i ndes-

rarely

Maintenance minimal.

Civil construction simplified and costs reduced .

No surge flows on fina l tanks.

Low noise values.

Automatic Dissolved Oxygen control systems avai lable.

Please send to r B roch ure No. FB DD 675

~ Hawker Siddeley

Engineering Pty. Limited

lncorporotod lnN.S.W.

Head Office : 262-284 Heidelberg Road , Fairfield , 3078.

Branches : Sydney, Brisbane, Perth and Auckland (N.Z.) Hawker Siddeley Group supplies electrical and mechanical equipment with world-wide sales and service.

Agents for : Hawker Siddeley Water Engineering Ltd . (Templewood Hawksley Activ?led Sludge)

28

2069 HSE

WATER

AQUA..-GUARD

A Continuous Self-Cleaning Sar/Filter Screen FOR:

0 0 0 0 0 C>

Sea, Lake & River Intake

O

Industrial Separation Processes

C> C>

Harvesting Debris from Waterways ;).

Potable Water Treatment Primary Sewage Industrial Circulating Water Industrial Plant Effluents Industrial Process Liquids

Pump Protection

V,J

PTY. LTD. 3 Bowen Crescent, MELBOURNE. 3004. AUSTRALIA Telephone: 267-1333, Telex: 31-308

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.

32 Hastie Avenue, MANGE RE, AUCKLAND, NEW ZEALAND Telephone: 633-969, Telex: NZ-2473 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 te5t in g systems and machinery Self--cleaning Bar/Filter Screening Testing Equipment for p&inting industry Pu lp Machines & Nozzles Paper machinery testing equipment Paper machine roll grinders Mullen board testing instruments

fiJE~LT

~

51-IARl=JLES CENTRIFUGES

Sharples centrifuges for wastewater treatment

Sharples Super- D-Ca nter ® sol id-bowl. conti nuousdischarge centrifuge.

Sharples SludgePak® solid -bowl centrifuge with skimmer and knife .

Sharples Nozljector ® disc-type , continuous centrifuge with internal re cyc le con cen trator.

No single type of wastewater centrifuge can handle all sludges - that's why Sharples makes all types.

SHARPLES-STOKES PTY. LTD. MAIL: BOX 367, ARTARMOl:J. N.S. W. 2064 PHONE: SYDNEY 439-3378/4458 CABLES: PENNWALT SYDNEY