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Volume 27 No 1 January/ February 2000 Journal Australian Water Association Editorial Board F R Bishop , Chair111an

13 N Anderson, D Deere, P Dr,1,1ye", W J Dulfc,, G Finlayson.GA H older. M Kirk, M Muntisov. N Orr, P Nadt·baurn, J D Parker. M Pascoe, A J

CONTENTS

Priestley, J R issman, F ls.oddick, E A Swinton

·, Jl'111er is a refereed journal. This symbol indicates that a paper has been refereed.

Submissions

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

Submissions should be made to E A (Bob) Swinton . Features Editor (sec bl'iow for details).

General Editor Peter Stirling PO Box 84, Hampton Vic 3188 Tel (03) 9555 7377 Fax (03) 9555 7599

MY

4 Pleasant View Cres. Wheelers Hill Vic 3 I 50 Tel/ Fax (03) 9560 4752 Email: swimonb@c03 I.aone.net.au

INDUSTRY

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Water (ISSN 0310 · 0367) is publishe_d in Jan uary. March. M ay, J uly, September and November.

Australian Water Association Inc

AWA

Federal President All en G ale C hri s Davis

PEOPLE

Kids' Congress 2000: 'Making a Difference' ... ... ...... ........... ...... ... ...... ......... 6 REGIONAL

CONFERENCES

NSW/Victoria: "Down the Track" ..................................................................................... 8 R eported by EA (B ob) Swinton Queensland: "Bugs, Bytes and Bits" ................................ ................ ............................... 9 R eported by R Drury WATER ·, Microfiltration for Water Treatment Comes of Age .. .. ........ .. ... ......... 11 G Fi nlayson , M Muntiso v ·, Membrane Systems Solve Pathogen Crisis in Canada ... .... ....... ..... .. 16 M Stadnyckyj , I) Oa kley Bendigo Gets Submerged Microfiltration .. ...... .... ... ................................. 18 R eport by EA (Bob) Swinto n ·, A Strategy for Removing Organic Contaminants ............................... 20 P Denn is, D Bailey , 13 Co le WASTEWATER ·, A Role for Supercritical Water Oxidation .... .. ........................... ...... .. .. 26 A Shanable h , N Crain ·, Treatment of Pharmaceutical Wastewater .... .. ... ... .. ... ... ... ..... ... ......... . 32 D Wiesn er ENVIRONMENT ·, Closing the Water Cycle ............ ........ ....... .. ...... ... ................. .................. 35 Langmuir, W Stoll ·, Using Cement Kiln Dust for Acid Soils .................. ................. .. ....... .. ... 37 G Palm er

J Parke r, S

ARBN 054 253 066

Executive Director

VIEW

Award Recognises Contribution to Women in the Water Industry .... ..... 6

Branch Correspondents ACT - Ian Bcrg111an T cl (02) 6230 I 039 Fax (02) 6230 6265 New South \Vales - Leonie Huxedurp Tel (02) 9895 5927 Fax (02) 9895 5967 Northern Terr itory - M ike Lawton Tel (08) 8924 641 1 Fax (08) 8924 64 I 0 Queensland - Tom B elgrave T el (07) 3810 7967 Fax (07) 3810 7964 Sou th Australia - Angela Colliver T e l (08) 8227 111 1 l' ax (08) 8227 11 00 Tasm ania - Eel K leywegt T cl (03) 6238 2841 Fax (03) 6234 7 109 Victo ria - Mike Muntiso v Tel (03) 9278 2200 Fax (03) 9600 1300 West ern Australia - Jane O liver T el (08) 9380 7454 Fax (08) 9388 1908

OF

www.WORLD.WITHOUT.WATER ... ..................... ..... ................. .. .......................... 3 D H ope

Features Editor E A (Bob) Swinton

POINT

AUSTRALIAN WA TE R ASSOCIATI ON

Australian Water Association (AWA) assumes no responsibility for opinions or statcn1cnts of faces expressed by contributors or advertisers. Editorials do not necessarily represent official AW A policy. Advertisemen ts are included as an infonnarion service co readc,~ and arc reviewed before publication to ensure relevance to the water environment and objectives of AW A. All material in Water is copyright and should not be reproduced wholly or in part without the written pem1ission of the General Editor.

Subscriptions I Varer is sent ro all AWA members six times a year. It is also available via subscription for $50 a year.

Visit the Australian Water HOME PAGE Auoc:lation and access our calendar, bookshop, membership fonns and 50 pages of lnfonnatlon et

BUSINESS ·, R ·, M

HACCP Application to Brisbane Water ............ ... ... .................. .. .. ......... 41 G ra y, M Mora in Excellence Through Continuous Improvement: 'Connectaflow '....... 43 H ill, D D ee re, G H anse n DEPARTMENTS

Aquaphemera ...... .. .. ..... .. .. ....... .. .. .. ..... .. .. .. ....... .. .. .. .. ......... .. .. .. ........... .. .. .. ..... .. .. .. 4 International Affiliates .................................................................................... 6 Membership ........................ .... .. .. ......... ... .. .......... ... ................. .... ...... .. ...... .. ...... 45 Water Index 1998-99 ... ................................................................................... 46 Meetings ........................... ...... .. ......... ..... ...... ... .. ............ ........ ....... ......... ...... ... .. 48 OUR COVER: 8 011/ac Foods Li111i1ed i11 co1,j1111a io11 111ith WSL Co11s11lta11ts 111011 a 1999 Victorian Engi11eeri11g Excelle11ce Award for rnstai11able de11elop111e111 a11d e1111iro11111e11tal desig11, for the SA 150 111illio11 gree11jield milk po111der pla111 at Dam11111, Victoria . The paper 011 page 35 ,<zi11es derails cif the closed loop 111ater cycle a11d is a11 expa11ded 11ersio11 of the paper prese11ted at the C leaner Prod11ctio11 Co1ifere11ce, Hobarl, A11g 11st I 999.


FROM

THE

PRESIDENT

HOLISTIC NATURAL RESOURCE MANAGEMENT As a long-standing practiti oner in water and e nvironm e nt iss ues, and moving from co nsultin g to o perations, I have come to realise chat a syste ms m an agement approac h to o ur key wate r issues is vital. As President of AW A I need to argu e fo r the ri ghtful place of water as a key resource fo r Australia. But I must also argu e for wa te r to be incl uded in a n integrated, syste m s approach to management. A paradox thrown up by this concept is that, in an e ra of great e mph asis on individual freedoms, natural resources arc only going to be sustainably managed by cu rtailing som e freedoms t hat people ex pec t to enjoy. Sc ie ntists arc showin g us just how interconnected things in li fe arc . A farmer w ho c hooses a partic ular cro p in NSW ultim ately has an effect on the sal inity of the Ri ve r Murray nea r Adelaid e; wh ile a subd ivision in a w ater supply catchment m ay compromi se th e hea lth of the consume rs wh ose water is coll ected th ere. In m y own area with Coulburn Valley Water we are fa c ing issues of increasing salin ity levels in our raw water. Salinity also is the primary issue for land reuse o f our reclaimed water. To make things wo rse, these connections are very complicated and m ay take decades to express the m se lves. M ore than ever befo re we need sc ie ntists to study natural resource syste111s, co 111odel chem and to advise us o n the li kely o utcomes of ou r actio ns. We can 'c expect th e m co make t he hard decisio ns, though , si nce they depend on soc ial and eco nomi c facto rs too. Scientists have co advise and political leaders and senior burea ucrats have to make the co ugh dec isi ons for o ur childrens' childre ns' good. Sadl y, politicians have co react to sho rt-term goa ls and to powerful vested interests. It will take stro ng views from broad constitu encies co pe rsuade o ur leade rs to adopt the long view on sustainability. So we face the double jeopardy of politic ians having to implement very long-term strategies that deli ver the111 no kudos now, by imposing what might seem co be draconian constraints on people o r businesses whose actions could impact natural resources and the e nviro nment detrimentally. Now that I have pa inted what seem s an impossible scenario - how can we ac hieve th e desired o utcome of sustainability? I think we need seve ral changes to come abo ut: 2

WATER JANUARY/ FEBRUARY 2000

Allen Gale

J. Natural resource manageme nt, based on catchm ents or bio-rcgions, needs to be placed o n a stro ng foo tin g, w ith the man aging age ncy having concurre nce powers. Th e curren t style of catc hm e nt 111anagcm cnt co111111ittccs, co111111on in seve ra l states, is an exce llent way to gee grassroots involve m e nt and co mmit111c nt at a loca l level. H owever, it does not have enough tee th to exe rt vital con tro ls, especially over land use decisions. AW A's submi ss ion t o th e P ar li amentary Co111111ittee o n Ca tch m ent Man agement suggested a need for better integration o f activities, improved communi ca tions and the develo pm ent of decision su ppo rt systems.

2. Scientific modelling has to be w idely applied to Australian issues: a task for which we probably don't have e nough t rai ned peopl e right now . Scie nce tends to be an orphan career, attractive o nly to t he so-called "ne rds", bu t th e rea l pote nti al and exci tement of a career in scie nce, especia lly wa te r sc ience, needs to be so ld to c hildren . We have started th is process w ith t he Stockholm Junior Water Prize in Australia and wi th the C D R om on water, but t here is still a lot to be done. 3. A mature d ialogue between governm ent, the science co111munity and sta keholders is needed, on the acceptance t hat we are all in this togethe r and must pu ll together. Our characteristically competi tive and ad versa rial approac h to inte ractions has co be put aside so we can forge vita l agreements on sustaina bility for ou r descendants. AW A is work ing to raise awareness of pol iticians and co establish a wate r forum to develop a coord inated approa c h to broad wate r related issues. I look forwa rd to tackling these issues with siste r associations, here and abroad, an d wit h gove rnm en ts a ll around Australia. I also look fo rward to all readers, and especia lly AW A m e mbe rs, workin g w ith all the stakeholders in Australia co bui ld a shared u nderstandin g of the critical issues we fa ce in taking ca re of water and the environm ent. T he prize warrants th e effort and th e price of failu re cannot be countenanced .

Allen Ga le

THE AUSTRALIAN WATER ASSOCIATION (AWA) OUR NEW NAME: EXPANDING OUR HORIZONS At the Federal Council meeting on 27th. November, it was decided to m ake th e name change which has been discussed throu ghout the Association for som e months. In announ c ing th e change, the President, Allen Cale, said that ado pting the more generic name 'Water' sends th e message out to everyone t hat this association is about th e whole water scene. W e are not just an urban water and sewerage group . Th e histo ric attention to urban water and sewerage topics is by no means disappea ring, but it is now standing n ext to ca tchment managem ent, salinity issues and the whole aquatic environment. The nam e change also reflects a more contemporary and integrated approach to water managem ent and the water business.

Although the new name re flects a broader scope, our growi ng list of specialised interest groups will e nable members to exchange re leva nt information pertai ning to their jobs or interests. Our A ssoc ia tion wi ll d evel o p fu rther collaboratio n wi th complementary o rganisati ons, suc h as th e Storm water Industry Assoc iation, the Irrigation Assoc iati o n, the Institute of W ater Admin istratio n (in V icto ri a) and the Water D irectorate (in NSW). At the same tim e, we have established strong lin ks w ith Th e Ameri can Water Works A ssoc iation, C IWEM a nd the Inter n at i o n al W ater Assoc iation, fo rmed from the m ergi ng of IA WQ and lWSA.


,:II

WATER

MICROFILTRATION FOR WATER TREATMENT COMES OF AGE Abstract M ic rofiltrati o n has matu re d fr o m a n e w a nd d ev el o pin g tec hn o logy, to a positio n where it is an o th e r use ful un it process in wate r and wastewa ter treatm e nt. • MF provides th e unique ad vantage of always re mo ving particles larger than th e po re size (typically 0.1 to 0.2 ~m1), w h ich m eans that hi g h qu a li t y wa t e r ca n b e produ ced with low ri sk. • MF pla nts arc beco m in g cost co mpe ti t ive w ith conve nti o nal pro cesses. A fibre bundle, cut open • MF has some uni que limitati on s, w hich need to be co nsidered in Th e re are two aspects o f 111 ic rofiltrades ig n and impl em entation. t io n w hi c h arc uniqu e co mpared to th e • The re arc nu m ero us plants install ed trad ition al sa nd (m ed ia) filtratio n process world w ide, wi t h seve ral large r tha n used to ac hieve re m oval of th ese contam 100 M L/ d. inants. Th e first is that ofte n mi crofiltra• Th ere is increasing and robust market tion ca n ac hi eve th ese rem ovals wit h no competitio n , and ;1ccelcrati ng techn ica l pre trea tm ent, coag ulatio n o r c hem ical development, w hich suggests that prices dosing. Th e seco nd is th at t hese leve ls o f wi ll redu ce and perfo rmance will improve. rem ova l arc achieved all the time, regardless o f how the system is ope rated. Introduction A we ll o perate d and desig ned sa nd Micro filt rat io n is often co midered to filter ca n achie ve rem oval of partic les in be a sli g htl y better substi tute fo r sand thi s size range, but this pe rform ance is filt ra tio n , but it is in fac t a quite d iffe re nt d e p e n d e n t on pro p e r and we ll process. T he economi cs of m ic ro filtram aintain ed c hemi cal dosin g, and the tio n and the wate r treatme n t marke t have perfo rman ce m ay fa ll o ff d urin g th e filte r changed, and the numbe r o f MF plants in rip e n ing pe ri o d, pa rt ic ul arl y a ft e r a use is rapidl y inc reasing . back w ash , and w ill also fa ll o ff afte r T his paper se ts ou t to explain m icroperiods of heavy loa d ing if th e run tim e filtration ; its ad vanta ges and lim itati o ns in is exte nded. Th e quality of fi ltrate ca n funda m e ntal terms, in th e co ntext o f this also be affected if the bed is disturbed. chan ging scen e. By co ntrast, MF w ill ac hieve hig h What is microfiltration? re m oval le ve ls, I 00% of th e tim e, M icrofi ltration is a sepa ration process. witho ut the ne ed fo r ap propriate c he mical d ose rates, or ca reful operatio n. An inta ct mi c rofi ltrati o n m e mbra ne Ge nerally, it is accepted that sand filtraexclu des all parti cles larger than th e po re tio n can achi eve aro und 2 to 3 lo g removal size , typically 0 .1to 0.2 µ111 . In w ater trea tme nt, this m eans that th e foll o win g (99 to 99.9%) of particles in the 2 to 8 µ111 particles of inte res t are excluded . size range, w hile results high er than 6 log • Mi cro-o rgani sm s includin g ba c te ria have bee n repo rted for MF. In summary, (su c h as co lifo rms) and c ysts such as microfiltratio n provides a reliable, easil y G ia rdia and C ry ptospo rid iu m. o perated barrier against particles g reater • Turbidity; M icrofiltered water has a very than 0.2 pm in size. low turbidi ty, generally less than 0.1 N T U . A numbe r of man u fa c ture rs o ffe r • A signifi c ant proportion o f th e ultrafiltrati o n (UF) m embranes (po re size colloidal particles w h ich can co ntribute ty pi cally 0.005 to 0.1 pm). UF plants are to c o lo ur and organi c loads. very sim ilar to MF plants. It wou ld be

reasonable to expect that MF would give hig he r flows at lo wer pressures. However, in prac tice , this diffe re nce is no t appare nt, w hi c h prob a bly m e an s th a t fouling o n the m e111branc surfa ce controls th e flo w, rath er than th e pore size . Given th ese fa cto rs, U F is co nside red equi va le nt to MF in this rcvievv. In th e future , it is possibl e th at UF w ill be more e ffect ive again st so me conta111i nants, with viruses being o ne ca ndidate, in fac t virus .re 111oval of 2.5 to 4 log has be en clai111 cd by o ne m anufacture r.

How are MF membranes constructed? Mic rofil trat io n m em branes have bee n co nstru cted fro m a vari ety o f materials, includin g steel, ceramics, and a wide range o f po lym e rs. N early all me mbran es used in wate r treat111 c nt arc based on so m e form o f po lym er. T y pica lly, th e polym e r is fo rm ed in to a poro us tub e kn own as a m embrane fibre, man y o f w h ic h m ake up th e 'fi lam e n ts ' o r 'spaghe tti ' w hich ca n be see n ins id e a m e mbrane m odul e w he n it is cut apart. A m embrane module is a ho usin g w hi c h co n tain s b un dle s o f seve ral tho usands o f the fibres. A typi cal plant th e n contains from several to hundreds o f th e modu les to mak e up a system. Th e c hoi ce o f m e mbran e made by a desig ner and develo per is base d o n a tradeoff be t ween a number o f differe nt o pposing fac to rs and manufacture rs use di ffe re nt approaches to achi eve a balan ce betwee n t hese properties. Studies have tried to identify the 'best' m e mbra ne m a te rial a nd m e th o d of construc ti o n . However, if a less than ' ideal ' m e mbran e can be install ed and operated successfull y at less cost, th ese differen ces arc large ly o f acade mic interest to th e e nd use r.

Practical Aspects of MF Sizing

T he first issue is th e water te mperature, as MF is temperature dependent. The WATER JANUARY/ FEBRUARY 2000

11


WATER

capacity of a given area of membranes is about 50% higher at 30°C than it is at 5°C. The second issue is to estimate the area of membranes required. This is dependent on a paramete r called th e membrane 'flux', whic h is simply the specifi c flowrate of water produced per unit area of membran e surface . Th e fl ux adopted will depend on the water being treated, and a nu mber of other fa ctors. T ypical design flow rates fo r surface water plants tend to be of the o rder of 50 to 120 L/m2 hr. The fl ux could also be quoted in the units m / hr, wh ich is more typi ca lly used in the water industry. T he range above corresponds to 0 .05 to 0.0 12 m / hr compared to typical values of around 10 111/ hr for a sand filter, indicating th.at a filtration area aro und 200 times greater is needed fo r MF than for sa nd filtration. Howev e r, th e footprint of a MF plant is typically mu ch less than th e equi vale nt sand fil ter because the extended area is ach ieved by the multiple fine fibres. Driving force

Transmembran e press ure (TMP) provides the driving fo rce fo r flow. This is equivalent to the headloss fo r a sand fi.lter, and if a m embrane is operated at a constant fl ux, the head loss will rise over time. The TMP required is of th e order of 100 to 200 kPa (10 111) for m ost pressurised systems . T he d riving head required fo r M F can often be suppli ed by gravity rather than pumping. It is worthwh ile reviewing the hydraulic profile o f proposed sites to possibly save o n power costs for pumping. As a run progresses, the T MP increases with the build up of contaminan ts on the m embrane surface. This pressure build up is then co untered by backwashing (a physical process) which occu rs every 30 mins or so . Each suppli er has a unique and often patented backwash process. Backwashing is not 100% effective, so c hemi ca l cleani n g is occasion al ly required. Cleaning is typically conducted in place by recirculating and soaking the membranes in dilute solu tions of caustic, acids and oxidants such as chlorine. So m e sup pli ers use a chlorinated backwash, so that a type of ch emical clean occu rs quite regularly. M ore rigorous cleanin g takes place less fre qu en tl y, with intervals ranging from 1 week to 6 m onths reported .

Filtrate Pump

Membrane Modules

Backwash Pump

Figure 1: Schematic of submerged membrane filtration system Th e fi rst is "Crossflow Filtration " where the water is pumped arou nd the system at high speed , thus creating a high flow along eac h fibre, wh ich reduces fou ling but increases p um ping costs . A second and very common co n fig uration is " Di rect Filtration" where the wa ter is pumped direc tly into the membrane (either by a pump or by gravity head if available). Here , fo uling can be an issue an d effecti ve backwashing is requ ired . A third configuration , commercially develo ped in the 90s, is "S ubmerged M embrane Filtration" . H ere, th e fi bre bundles han g free ly in a tank of raw water, and th e head a b ove th e membranes combines with the suction draw from filtered water pumps to 'pu ll ' the water thro ugh. Th e transm embran e press ure (or suction) is typ ica lly 14-50 k Pa, less than normally emp loyed for p ressurise d systems.The water on the dirty side of the membranes can be agitated by an

'air-sco ur' to help cl ea n the outside of the fibres. As the solids co ncen tration in the tank bu ilds up it may be reduced by intermittent or co nstant blow-down. T he principal advantage of this system appears to be that it is cheaper, particularly fo r large plants. T his is the configu ration used by both US Filter and Zenon for large plants. (See Figu res 1 and 2) .

Real World Limitations of MF 1 . Fouling

Many substances can adh ere or collect on a m embrane surface. Some water qu ality parameters w hi ch suggest that fo ulin g m ay be a problem include high organics, algal loading and hi gh silicate levels. Surface water has variable composition, and it is difficul t to predict the fou ling problems that cou ld occur. In simple terms, fou ling gums up the m embrane surface, ' blocking' th e pores an d redu cin g the flow through the m embrane. This usually means that the TMP requi red to drive th e system

System Configurations

There are thre e main con fi gurations for me mbrane systems which are in use in water treatment. There are numerous other option s being explo red by developers.

12

WATER JANUARY/ FEBRUARY 2000

Figure 2: Isometric drawing of the 126 ML/ d US filter plant fo r Caliban Water (see also page 18)


Table 1: Current Market Position of MF for Water Treatment Supplier

USF Memcor

Aquasource

Zenon

Pall

Koch

XwFlow

Pore Size

0.2 µm Polypropylene

0.01 µm Cellulose

0.03 to 0.1 µm Organic polymer Submerged

0.015 µm Polyacrylonitrlle

0.005 to 0.5 µm Polysulphone

Direct Filtration

Crossflow

0.1 µm Polyethersulphone/ polyvf nyl pyrro Iidone Dlrect;cross flow hybrid

>80 ML/d

>20 ML/d

>50 ML/d

Membrane

acetate

Material

Configuration

Direct and submerged

Cross flow

Total Installed or

contracted capacity > 500 ML/d

> 400 ML/d

>50 ML/d

Source:- Oosterom et a!. & information obtained from suppliers and their Hterature.

increases, until eventually the capacity of the plant is reduced. Note that this is significantly different to the mode of failure for a sand filter, which would typically foil by a reduction in water quality rather than quantity. Fouling can be avoided by selecting a membrane which does not foul with the particular foulant, using appropriate pretreatment or some form of chemical dosing. Unfortunately, most of these options are best dealt with at the design stage, when the fouling problem may not be evident. Therefore the best strategy is to run reasonable scale pilot trials to determine the best membrane and design on the water in guestion. In most cases fouling can be removed by chemical cleaning of the membranes. It may take the application of trial and error to determine the best chemical(s). This reinforces the benefit of pilot trials, as the cleaning chemicals to deal with particular fouling problems can be determined.

System Integrity The benefits of microfiltration are related to the fact that no particles of greater than 0.1 to 0.2 ~Lm will pass the membrane. However, this is not true if the membranes have holes significantly greater than the pore size. If enough fibres have failed, the system is not acting as a microfilter, and these benefits are lost. Fibres are essentially a small diameter plastic tube. They are subject to physical forces from movement (say during a backwash), and damage from abrasion, and other forces from the particles in the water. The fibres may suffer from chemical attack and may have manufacturing defects which only become evident over time. It is often impossible to determine why a membrane has failed. There are two main methods used to detect fibre failure. The first is to perform some sort of sensitive measurement on the guality of the filtrate, with a particle counter the obvious choice for an instrument. A particle counter will show a deterioration in the water quality if a significant amount of the flow is

bypassing the membranes through a fibre failure or some other leak path such as a faulty O-ring seal. Note that on a large plant, there may need to be several instruments, each on a separate 'bank', to avoid having any one failure averaged out. A problem with this test is that there must be a measurable, (and therefore significant) degree of failure before it can be detected, although particle counters are reputed to be able to detect two breaks in a bundle of 256000 fibres. The second method is to use an air pressure hold test. The laws of air bubble formation in water show that at a pressure of 50 to 100 kPa, the size of air bubbles will be greater than 0.2 µm. Therefore air at these pressures will not pass a wetted membrane. One investigation by a user demonstrated a straight-line correlation between the rate of leakage and the number of fibres deliberately broken. One supplier claims that failures of a single fibre can be detected using this method. A problem with this test is that it requires the plant to be offiine while it is performed and therefore it cannot be carried out continuously. Once a fibre failure has been detected, there are a number of different technigues used to detect which individual module has the problem. These techniques generally involve the use of air bubbles and then either sonic or visual identification. The repair method varies from manufacturer to manufacturer. Generally, the standard cure is to plug both ends of the offending fibre and then it cannot leak, or supply water. A large number of fibres need to fail before this is impractical, or before the overall capacity of the system is reduced. Service contracts which offer assistance with this, together with some form of commercial arrangement on membrane replacement cost arc becoming common. Waste Strea1ns: MF produces a number of waste streams: • Backwash, and blowdown of the tank water for immersed membranes. Thus MF produces a waste stream which is

around 5 to 10% of the total flow (at least double that produced by a sand filter.) If the MF plant is operating without prefiltration this stream may be high in solids, and may not settle easily. In many cases, chemical dosing of the backwash stream is advisable to ensure settling, and possible recycle of the supernatant. • Cleaning Waste: MF plants need chemical cleans, and eventually a concentrated and dirty chemical stream will need disposal. Possible routes for this include sewer, neutralisation and then to sewer or to a washwater system, or trucking offiite.

Available Systems Table 1 summarises some of the major suppliers, and some aspects of their technology. Microfiltration appears to be competitive on a capital cost basis with more traditional separation/sand filtration plants up to around 10 ML/ d. This is a significant reduction in price over the last 5 years. There is also greater acceptance of MF technology, as indicated by the number of projects specifying MF outright. Recent Australian examples of this are the 6 ML/d plant at 13amaga in North Qld, and two other projects; one at 20 ML/d and the other at 45 ML/d, where MF has been identified as the preferred technology. Where the specifications for treated water guality are more stringent, for example if high levels of guaranteed Cryptosporidi11111 and Giardia removal are required, then microfiltration appears competitive up to 100 ML/d. This is borne out by the number of 100 ML/d plus plants worldwide. Pertinent local examples using the submerged membrane system include the Bendigo, Victoria 'Agua 2000' project, where US Filter is constructing a 120 ML/d MF plant, and the Waikato project in NZ, which will incorporate Zenon membranes to an ultimate capacity of 150 ML/d. In terms of capital cost, it appears that the submerged process is quite competitive with conventional treatment WATER JANUARY /FEBRUARY 2000

13


MEET US AT YOUR LOCAL WATERING HOLE

USiF

Part of Vivendi Water.

We' re the worl d's largest manufac turer of water an d wastewater treatment systems. But we ' re also your neig hbours. Chanc es are, there are USF people and produc ts hard at work in your town or city. Wi th techno logies and services ranging fro m mi crofil tration to chemi cal feed to co mpl ete fac ili ty construction and operati o n, USF offers ma ny solutions to he lp you meet you r water a nd wastewater goa ls and requirements. To learn more about USF, call us at the numbers be low or visit our web site at www.usfilter.com.

USF-REGIONAL HQ (SYDNEY)

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Phone: 02 8875 2800 Fax: 02 8875 2700

Phone: 03 9824 4955 Fax: 03 9824 4966

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USF-BRJSBANE

USF-PERTH

Phone: 08 833 I 8088 08 8364 2878

Phone: 07 3867 5500 Fax: 07 3862 1834

Phone: 08 9470 7000 Fax: 08 9470 1319

Fax :

Toll Free Phone: 1800 677 667 Ema il: usf@ us filt er.com .au Web : http://ww w.usfilter.com.au

USF Permutit

USF Memcor

USF Johnson Screens

USF Wallace & Tiernan

USF Stranco


WATER

processes if th e m e m brane costs are exc lud ed. The larger the plant, th e larger th e m e m bran e inventory, w hi ch ca n ha ve a valu e of aro und 20% o f the ca pital price. Th ere is a significa nt on going expenditure related to regular re placen1.ent of th e m e mbranes. M an y supplie rs are offe ring a lease arrange m e nt co carry th e risk asso c iated with m embrane life.

What does the future hold for MF? The foll ow in g ar e lik e ly futur e o u tco m es fo r MF , based o n c urre nt progress. • Increasingly strin ge nt water qu ality re q u ire m e nts w orldwide will d ri ve th e push for be tter pe rforming plants, w ith less risk of w ater q uality excu rsio ns. T h ere fore, de ma nd for MF wiU in crease. • An area o f chan ge w il l be the deve lop ment of ne w m e mbra nes. T h is could include the deve lo pme nt of spe cialist m e mbra nes suitable fo r partic ular w ate rs o r duties. Fo r exa m ple, th e role of ultrafiltration m e mbran es m ay inc rease, on w ate rs wh ere th e addi tio na l m ate ria l remo ve d at the tighte r po re size is re leva nt (viru s removal is a possible candidate) . Ano th er examp le might be a m e mbran e w hi c h is c hemi ca ll y stable, allowin g its use in a co mbi ned train w ith o zo ne o r so me othe r stron g ox idant. • A major area o f chan ge w ill be cheap er syste ms. T he re arc now seve ral companies wh o ha ve bu ilt plants of20 ML/ d or larger. Th is m eans that real compe titi o n has e m e rged , w hi ch w ill drive prices do w n. M e mbra n es are still a sm all pro du c t ion ite m, a nd t yp icall y still involve a degree o f m anual handl ing to co nstruct. As the size and numbe r of plants in c r eases, th e vo lum e o f m e mbran es suppli ed w il l increase, and ne w manu fac turing tec hniques and othe r eco nomi es m ay red uce costs. • G eneric system designs. In the early days of R everse O sm osis, it was only possible to use on e suppliers me mbranes in any o ne plant. E ventua ll y, plant design established standards fo r m e mbran e housings so that m e mbranes from any supplier can be used in any plant. This would be a possible and positive move of the future for MF , as it will remove a barrier to free compe titio n fo r m embran e replace m ent, and provide the oppo rtun ity for suppl ie rs to specialise i n produ c ing n ew a nd impro ve d m embranes, w itho ut th e need to w m co ntracts for the construction of new plants to see th em in use. • R e trofit of Sand Filte rs? Thi s is a huge pote ntial m arket for MF, w here des igns migh t b e de ve lope d to re trofit th e hundre ds o f thousands of sand filt ers worldw ide. T here are a number of inter-

es tin g a n d c h a ll eng i n g t ec hni ca l pro ble m s to be solved , but th e co ncept is fund amentally sound . Provided th e vario us techni cal and comm ercial challe nges are m et, MF (o r UF) w ill eventually be the tec hn ology of c hoice fo r filtration o f surface waters. Finally, the reli able particl e rem ova l offe red by MF (or U F) m eans that it w ill becom e an integral part o f m any waste wa te r reuse sc hem es, parti cul arly fo r potabl e reuse .

Wiesner M.R.. ( 1996) Water Trear111e11r .\lrmbra11e Pn,c1·sses. AWWA R e search Foundat io n . McGraw H ill 2 . Oosterom H .A .. NederlofM .M. and Vos G ., M . F and U.F for the treatm ent o f surfa ce water in the Netherlands. Proc. A WI VA 1\ lc111brm1c ·1cc/11,olc\~Y Co,!fereuce I 999. 3. Aleese P., M oody C. et al. lntl'graced M emb rane Systems Pilot T est Program fo r th e O livenha in W ater Storage Project. Pmc. A I VI VA ,\ /e111br,111c Tcch11,,lo,~y Co1!{aC11ce 1999.

Authors

References I. M allevialle,

J.

Greg Finlayson and Mike Muntisov are w ith GHD , M e lbou rn e.

and Oden daal P. E. and

DISINFECTION: • PORTACEL Chlorination Equipment and Instrumentation • HANOVIA Ultra Violet • CHLOR GENERATORS on site electrochlorination • PORTACEL Vacuum Sodium Hypochlorite System

MONITORING: • Chlorine Residual (Free and Total) • Gas in Air (CL2 , S02 , NH 3 ) • Chemical Container Weight (Drum Weigh Scales) • Particle Counting Systems • Chemical Inventory Management

CONTROL • Flow Proportional Dosing • Chlorine Residual Control • Flow and Residual Control • Chemical Process Controller

WATER JAN UARY / FEBRU ARY 2000

15


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WATER

MEMBRANE SYSTEMS SOLVE PATHOGEN CRISIS IN CANADA M Stadnyckyj and D Oakley Introduction For the Collingwood Public U tilities Commission (CPUC) located in Ontario, Canada, n1.embrane technology has proved to be the solution to a cryptosporidi11111 crisis. With a seasonal population of over 16,000, including many resort condominiums and hotels, the Town of Colli ngwood draws raw water fro m Lake Huron. T he water intake extends 600 m eters into G eorgian Bay to a depth of approximately 7.6 m eters. Water quality has historically been good with no taste, odour or colour problems at the site. O1iginally, the only form of treatment was chlorination. In 1996 isolated cases of cryptosporidosis were suspected , and as a result th e local M edical Officer issued a boil water orde r for the coun ty, which lasted for 171 days. The intense public con cern had major ramifications, particularly the pote ntial effect o n o n e of its maj or industries - tourism. As an interim measure th e C PU C leased three packaged R everse Osmosis units from the Zenon Environm ental Inc. of Ontario wh ich were ulti mately converted to Ultrafiltration (UF) plants w hich supplied the hospitals and key distribution points. Once th e immediate needs were met, the CPU C moved ahead with the installation of a temporary treatm ent plant of UF m embranes in a number of co nta iners. The CPUC the n had the task of selec ting a technology for the permanent plant. A detailed investi gatio n that exa mined point- of- use devices, ozonati on , conventional filtration and several m embrane techn o logies was undertaken . Th e CPUC co ncluded that the most appropriate solution must inco rporate an absolute physical barrie r to cryptosporidiu111 ente ring the distribution system. Th e Zee W eed Immersed Membran e System was selected utilisin g a UF me mbran e with a pore size of 0.04 Âľm.

Process Description The Collingwood Water Treatment System is designed for a flow of 30 M L/day and consists of five independent parallel tanks eac h equipped with a dedicated permeate pump and blower. (Fi gu re 1). Wh en co mpa red to pressurized mem bran e systems, w here the train

16

WATER JANUARY /FEBRUARY 2000

size is typicaJly limited to ap p roximate ly 4 ML/d , thi s grea tly redu ces the amount of ancillary equ ip ment, pumps, blowers and valves. The raw water is pre-sc reened, chlorin ated for biologi ca l growth control and dire cted into t h e Im mersed M embrane tanks with no furthe r pre-treatment. Within t h e process tanks, individual membrane modules ar e co m bined to form cassettes Figure 1: The membranes are immersed in process tanks (F igure 2) . At th e which can be designed to process up to 20 ML/ d Co lli ngwood pl a nt membrane and minimizes the se ttling of each proc ess tank con tains twe l ve solids. Aeration has th e additional benefit cassettes with eight modules in each of destroyi ng readily oxidizable organ ics, (cassettes are typica lly fo rmed wi th 2- 12 micro-precipitatin g certain metals su ch m odules) . Each p rocess tank contains as iro n and sc ru bbing volatile organics 4,500 111 2 of me mbrane surface area, fo r and hydrogen sulfide, r esul tin g in a total of 22,000 111 2 . This design is very potable water better than that just treated flexible and can be easily upgraded to by filtration alone. Some product water meet increased demand by simply adding is diverted to a Clean in Place (C IP) casse ttes to a train. Tank and typically every 15-30 minu tes Filtration is achieved by drawing water for a short duratio n of 15- 40 seconds the to the inside of the membrane fiber under flow is re versed. The po res of the a suction of 14-50 kPa. into upper and m e m b ra ne sli ghtly ex pand an d any low e r h eaders . Typic al resu lts are trapped particles are flu shed ou t. The summarised in Table 1. C IP tank is commonly lo cated above the The op erati o n is highl y a u tom at ed with a Process Logic Control (PLC) system mon i torin g and controlli ng actuated va l ves an d m aki n g minor adjustments to pump speeds, liquid levels, etc, as requi red to maintain optimized system performance.

Minimizing Fouling In t h e Zenon system, air is bubbled con tinuo usly through th e tan k during filtratio n, wh ic h scou rs the surface of the

Figure 2: The cassettes are immersed directly in the process water tanks, which have pre-arranged guide slots


WATER

m embrane processing tanks, allowing the backpu lse to be gravity fed. Th e purge is eithe r fed to an inde pend e nt ind ustrial water supply reservo ir o r discharged to the Bay. This sys te 111 allows chemi cal cleaning to be red uced to approx i111 ately 4 tim es pe r year. The prima ry m e 111bran e cleaner is c hlorine. C lean ing can be don e in an e 111 pty or a full tank. Empty tank cleanin g offers t he be n efits of usin g full strength clean ing sol ution and generating a lower volu 111e of waste .

System Integrity Membrane in tegrity is verified daily with an au tomated air pressure decay test, an d compro mised fi bers can be observed b y the strea m of bubbles and easily re paired in th e fi eld. Pa rticle cou n te rs co ntin uo usly m onitor the fi ltered water to ensu re integrity o f the syste m at all tim es . ZeeWeed® lm 111ersed Membran es have bee n o perating at th e Colli ngwood site sin ce 1997 in the temporary UF water fi ltration ta nks. Th ese me m branes w e re transported to the perma nent faci lity in 1998 w ith no 111ajor start- u p or op e rating p roblem s to date .

Table 1: Typica l ZeeWeed® Syst em Results Feed Water

Turbidity Color

TOC Fe Mn Giardia Cysts Cryptosporidium Oocysts Virus

100-5 00 NTU 5-200 Pt/Co units 3-30 mg/L > 10 000 µg > 5 000 µg

Treated Wate r

<0.1 NTU < 5 Pt/Co units

*

50-90% removal * < 100 µg < 50 µg > 9 log removal > 9 log removal >2 log removal

* Color and TOC removal is dependent on raw water quality

Conclusion As potable water regulations continue to increase and fres h water sources are furth e r c om p ro m ise d , m e 111bran e tech nologies will be increasingly em ployed by muni cipaliti es co overcom e th ese challenges. O livenha in M unicipal Water District in San Diego have rece ntl y chosen a ZeeWeed® [111111ersed M embran es fo r their new ·107 ML/d drinking water plant, after com parative evaluation b y the US Bureau of R.ecla111ation and a 12 1110 11th trial on site . This proj ect represen ts the largest ultrafiltration con tract awarded in North Ame1ica. A new Zee W eccl® syste 111

will also be built o n N ew Zealand's Waikato R iver to service the city of Auckland. T he plant will initially suppl y -1-5 ML/d w ith future expa nsion to over triple its o riginal size

Authors Mike Stadnyckyj is in C orporate D evelopm e nt for ZENON En viron m en t Inc, Toro n to, O n tario, C anada. Em ail : m stad n yc @ ze n o n e nv. co m. David Oakley is Environmen tal Sa les M anager for !<...oils- R oyce Au st ra lia Ltd w h ich ope rates a li cenc ing agreem e nt with Z E NON E n v iron m e ntal I n c . for Australasia and the P acific.

Engineering Services State Water Projects Queensland Department of Natural Resources

Tel: 07 3224 8311 Fax: 07 3224 8922

A-ovidino award 'Mnnino 'M:rter infrastructure enoineerino and desian. construdioo manaaerrent. survevino and aeotechnical investiaatioo


WATER

BENDIGO GETS SUBMERGED MICROFILTRATION Report by EA (Bob} Swinton The Aqua 2000 project was wa t e r mediu m , th e b e d /m111ched 011 October 14th 1999 collapses and is thoroughl y i11 11 gro1111dbre11ki11g ceremony agitated, t he e ffl ue nt being diverted to a sludge lagoon fo r next to the S1111d/1urst reservoir, clarification and recycle. Be11digo, Victoria, peifom1ed by At the time of the demontl1e Cl111inn1111of Caliban Water, Cordo11 JV/cKem, 1111d the stra ti on, the clarifier was M111111gi11g Director of US Filter produc in g abou t l -2 N TU A 11s tralia, A 11dre1v J o11es. water, and the m icrofiltered Colib1111 Water has th11s e11s11red product turbidity m ete r was tl111t rheir 1v11ter qudlity 111ill meet readin g 0.012 NTU. A particle th e demands eve11 of f11t11re co unter was also in operation, standards . . . . a 111ove into rl1e and work is in progress to next 111ille11i11111. Tl1 is will h1111e 11 develop a quality specification tre111e11do11s i111pact 011 the region based on particle counts, there served by Colib1111 l;J/ater, s0111e being no standard currently 130, 000 pop11latio11, 110/ j11st for ava ilable . do111 estic rnpply, b11t also e1111bli11g the food i11d11stries to Figure 1: A single module undergoing prolonged t esting Full-scale plant expa11d. C eo.ff Michel, CEO of on reservoir wat er W ith the success of the Coliba11 vf/ater, 011tli11ed the ' process verifica tion' a 25 year develop111e11t of the BOOT contract whereby needed to maintain the fib res in pristine BOOT contract has now been signed US Filter A11strali11, operating thro11gh a condition, but the the polypropylene for the construction and operatio n of a rnbsidiary 11a111ed USF Beudigo Water fi bres ha ve an extre mely long li fespan .. fu ll-scale p lant, with a capacity of 126Services, will build and operate the pl11111ji>I' tl1e T he other advantage is that the open 150 ML/ d , by simple replication of the tank system is more suited to large plants, period of 25 years.

Process verification A single m odule su bmerged m icrofiltration plant, Memco r® CMF-S, has bee n operated fo r some months fo r "process verification" by U S Filter A ustralia on the actual water fr om the Sandhurst reservoir, the m ain supply fo r Bendigo and surrou nd ing towns. At the ground-breaking ceremony to launc h the com mencement of the b u ilding of a fu ll-scale plan t, the visitors were shown the plant operating smoothly at the rate of 5.5 kL/h . T h e M e1n cor® C MF-S system is novel, only the second in Australia (a small plant is being operated in Marulan, NSW) in that although pressure microfi ltration is well-established worldwide, this system deploys the M emcor® ho llow fi bre bu ndles in an 'open' tank, and applies about half an atmosphere of suction to the inside of the fibres. T he advantage is that the fibres are easily cl ean ed each shift by shutting off the flow fo r a few minutes, and applying an air scour to th e tank, so that the fibre bundles are well agitated, the d irty water dra in ing to a sludge lagoon. Every few weeks a citri c acid/ sod ium hydroxide clean-in-place may be

18

WATER JANUARY/ FEBRUARY 2 00 0

rather than th e skid-m ounted pressure systems which have been installed for plants of up to 50 ML/ d, using the M em cor® microfiltration modu les which were developed in Australia and are now being exported wo rld-wide At intervals eac h fib re modu le is tested in place for 'integrity' by applyi ng a back air pressu re of some 100 Kpa . T his is insufficient to overcome the surface te nsio n of the sta ndard 0 .2 micron pores, but th e 'pressure-h old' is m onitored. Any larger holes whic h may have develop ed in a bundle will result in leakage, and the rate of fall of the pressure can be correlated with the potential leakage of particles. At a certain level, a module would be replaced. Although microfi lt ration can b e appli ed direct to a raw water, in this appl ication an upflow "adsorption clarifie r" is utili sed as a pre-clarifier, where flocc ula ted water is directly fi ltered upwards through a bed of polythen e b eads. T he beads have ne utral density, so that as soon as upflow is com m enced, the bed forms against the upper screen. The advan tage is tha t backwash is achieved by reducing the fl ow and combining it with an air-scour. In the lower density air-

microfiltration modules , m anifolded into co ncrete b as i ns . U S F il ter's con tract exte nds co the i nfrastru ctu re, delivery pipelines and service rese rvoirs, and also to three small er treatment p lanes in ou tlying townsh ips, two of them using pressu re microfi ltratio n , and a sma ll one designed fo r 0. 5M L/ d being a skid-mou nted combin ation of microfiltration and nanofiltration . T he project commenced in 1997 when Coliban Water advertised for expressions of interest for installation of a world's best practice system. Four proposals were investigated, reduced to two , then in May 1999 the US Filter Australia 's M emcor® C M F-S system was adopted and the ' process verification pla nt' commenced. The fu ll-scale plant is sc heduled to be operating in 2000, producing water of a quality exceeding the W H O standards for 110,000 customers and factories in Coliban Water's territory. Taste and odou r w ill be eli minated, and the microfi ltratio n system wi ll safegua rd against paras ites such as Cryptosporidil/111 and

Ciardia .


The Zllllocc® Process for

Waste later Treatment • • • • • • • •

Effective Nitrogen Removal Municipal and Industrial Applications Increases Plant Capacity Reduces Capital Expenditure Better Effluent Quality Operational Stability Reduction in Chemical Dosage Elimination / Marked Odour Reduction

ZEOLITE

AUSTRALIA

OXLEY CREEK PROJECT BRISBANE

ZEDLITE AUSTRALIA LIMITED Phone: 03 9699 4599 Facsimile: 03 9699 4522 Website: www.zeolite.com.au Email: info@zeolite.com.au

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WATER

A STRATEGY FOR REMOVING ORGANIC CONTAMINANTS P Dennis, D Bailey, B Cole Abstract As water quality monitoring and the understanding of the risks of organic con tam ination increases water authorities are faced with the issue of e nsuring commu nities receive unco n taminated drinking water. Developing a strategy for dea ling w ith organic co ntamination involves a number of stages including assessin g the risk of exposure to orga ni c contamin ation , developing catchment and water storage management plans, iden tifyi ng possible treatment options and developing contingency plans for deal in g with organi c contamination eve nts. Th is paper foc uses on a risk management approach and explores options for organic remo va l at the trea tme nt plant. Key Wo rds: Algal toxins, taste, odo ur, GAC, PAC, BAC , ozone, risk manageme nt.

Introduction Contamination of drinking water suppli es can be attributed to seve ral m icro-organisms including algae, bacteria, and fungi. Many of these organisms are capable of imparting tastes, odours and toxic compounds into drinking wa ter suppli es. Taste and odour problem s can be produced naturall y, produc ed as by products during water treatment disinfec tion , by substan ces that leach from water pip es or storage faci lities or so metimes from indu strial chemicals The most com mon contam inants of concern arc listed below: • Taste and Odour: 2-methylisoborneol (M IB) , geosmin . • Cyanobacteria tox ins: Mi crocysti ns (hepatoxins), Paralytic Shellfish Poisons (PSP neurotoxins including saxitoxin), Lipopolysaccharides,Cylindrosperm opsin. • Spillage from external so urces such as road tankers. • Pesticides from agricultural run-off The impacts o f taste an d odour co mpounds, w hile not conside red a public health risk, can range from mild to extremely objectionable and can ha ve a significant effect o n consum er confide nce . Cyanobacteria tox ins, on the other hand, have been shown in certain cases to be linked to tumour promotion in rats

20

WATER JANUARY/ FEBRUARY 2000

and evidence is also accum u la t ing on h ealt h effects 111 humans exposed to cyanobacteria. Evide n ce of li ver damage in humans has been linked to the presence of

Alert Levels 1 to 3 Inclusive

40 r - -- -- - - - - - - - - - - - - - -- ----, 35 30 25

20

Microcystis aemginosa 15 in potable water (Falconer, e t a l. , 10 1993). Operators of 5 water treatment plants need to have 0 ' - - - - - - - -- 1995/96 1996/97 1997/98 in p lace effective treatment techniqu es CRESSBROOK PERSEVERANCE COOBY and management plans for spo radi c Figure 1: Number of weeks under cyanobacterial alert fo r taste and odour Toowoomba storages problems to m eet due diligence requireme nts and to ensure three years the incidence of potentially co nsum er confidence. In terms of risk proble matic cyanobacteria in alJ three manage me nt a multiple barrier approach storages has increased. Th is is clearly including catchment management and shown in Figure 1 wh ic h shows the trea tmen t processes fo r re moval of in cide nce of cyanoba cterial blooms in o rganic conta m i nan t s is pre ferred. Cooby, Perseve ran ce an d Cressbrook Signifi cant resea rch and development dams over the years l 995/96, 1996/97 acti vity is foc used on thi s area of water and 1997 /98 . T h e worsening situ ation over this treatment and further design development and operating experi e nce is neces- period (particularly 1997 /98) is clearly sa1y to fully understand the mechan isms evident. involved. Water quality data fo r the storages were obtained and consisted of algal and Risk Assessment - A Case general physico-chemical data. Figure 2 Study, Toowoomba presents rece nt surface cyanobacterial Previous investigations GHD (1990), data from Cooby dam in standard time T CC Reports (1998) have highlighted series format. the potential problems for Toowoornba's A three tiered algal response plan for wa ter supply aris in g from var ious Toowoomba C ity Council was developed: co ntamination eve nts, especially th e Alert level 1 - ea rl y warni n g at 500 occ urrence o f blue g reen algae or 2000 ce ll/m l cyanobacteria. The dams are the principal urba n water supply for the city of A lert level 2 - established bloom 2000 15000 cell/ml Toowoomba (providi ng up to 85% of Alert level 3 - severe bloom > 15000 requ ire ments In th e past, Toowoomba City Mon itoring evidence shows that all Co un cil has been able to effectively the d ams have experienced varying m a na ge water quality p roblems in periods above alert level 2 (ie. 2,000 cells individual dams by taking the affected per millilitre) which is the level nationdam off-line and relying on su pply from ally recognised as a warning for drinking the other sou rces. However, th is strategy water supplies. At these levels (or lower has been thrown into doubt with the depen ding on species) taste and odou r recen t wa ter quality h isto ry o f the may become problematic due to algal Council's storages. metabolites and toxin levels will need to R.ecords indi cate that over the past be mon itored .


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WATER

aooo~------- - - - - - - - - - - - ---~ ..._ Anabaena

7000

Microcystsis

..... Cyhndrospermopsis

6000 5000 ...J

E

~ 4000

ai

<.> 3000

me n t managem e nt options available . It was therefore necessa ry to exa mine treatment options for the remov:tl of algal toxins fro m the drink i ng water supply.

Treatment Options 7 Jan 97

17 Apr 97

26 Jul 97

9 Nov 97

11 Feb 98

22 Moy 98

30 Avg 98

Conventional Treatment Previous work Qones et.al. 1993) , ( Falcon er et.al. 1983) and (Velzeboer 1995) has found that conventional treatm ent processes incorporati ng coagulation and fi ltration ma y re mo ve intact algal cells but cannot effective ly remove extracellular toxins and taste an d odour compounds. The proc esses w hich remove algal cells with a minimum of cell lysis are: • di ss ol ve d a i r flotation (DAF) / Filtration, • slow sand filtration, • microfiltration • con ventional clarification and filtration , • contact or direct filtration. T he removal of whole intact cells repre sents the best opportunity to remove toxins in separation processes. The literature indi cates r e moval efficiencies o f extracellular toxins are low. T h e possibilities of toxins being extra- cellular together with these low removal effici encies indicates separation processes while assisting in removal may not be relied u pon as the main removal process.

Evaluation Criteria Figure 2 : Cooby Dam cyanobacteria levels , 1997 to 1998 There are a number of criteCooby Dam s uffers mo st from ria that are important w hen assessing cy anobacterial blooms, princ ipa ll y various process o ptions for removal of Anabae11a and Cyli11drospen11opsis, ty pi cally ta rget contaminants. Th ese include: attaining concentrations of 10,000 to • process effective ness & reliability - is 20,000 ce lls p er millilitre, but reaching the process capable of re moving the full up to 80,000 cells per m illilitre, or more . rang e of orga ni c co ntamin a nts of Perseverance Dam suffers least from concern to below target levels. This cyanobacterial bloom s, both in term s of depends o n the levels of contamin ants absolute levels and durati o n of even ts. that are likely to be encountered in the Levels of A11abae11a and Microcystis are raw water so urce . ls the process reliable, typically less than 100 cells per millilitre are there certain conditions under whic h but short term peaks of u p to approxi- it w ill not perform to the des ire d Oxidation Processes mately 3,000 cells per millilitre have standard. Various oxidants have been demonbee n rec ord ed. • response tim e - Once an organic strated to successfully breakdown taste Cressbrook D am ex p e ri en ce s conta min ation event has been detected and odour compounds and algal toxins. moderate problems with cyanobacte- what is the response time to ha ve the ria, prim aril y A11abaeua, Microcystis and proc ess operating and re moving the A summary of these oxidants and their Cyli11drospem1 opsis. A11abae11a can reach contaminant to b elow target leve ls . effectiveness is provided in Table 1. Potassium permanganate, hydrogen leve ls t y pi c a ll y betw ee n 4,000 to R esponse tim e is also influenced by p eroxide, ultra violet light and chlorine 5,000 c e lls p e r millilitre, Microcystis monitoring fre qu ency. dioxide have been shown to be effective 3,000 to 4,000 ce lls per millilitre but • integration with the existi ng process in some cases for cylindrospermopsin and Cy/i11drospem1opsis has reac he d 14,000 the capability of integrating the process microcystin removal but show limited ce lls per millilitre . w ith existi ng water treatm ent infrastruceffective n ess for taste a nd odour Spring, summer and early autumn are ture or oth er assets. compound removal. The most effective the higher risk tim es of the year for • process cost - This includ es both oxid ants for taste, odour and toxin cyanobacteria l g r ow th , ho weve r, capital and op erating cost. The overall Cyli11drospen11opsis in Cooby Dam has finan cial costs of various processes is removal have b een found to be chlorine and ozone. remain ed at problematic levels through- sign ific a ntly influ e nc ed by both the out autumn and w inter. frequ e n cy a nd duration of organic Activated Carbon Adsorption In general, monitoring locations within contamination eve nts. Net present worth Activated carbon is produced from a each individual dam show similar algal values and se nsitivity analysis can been variety of raw materials and the source levels during bloom periods, suggestin g used as an indicator to assess th e overall material influences the effectiveness of that algal blooms do not form and spread financial imp lications of th e various the material. Raw materials include : from any specific foca l locations. coal, p eat, wood, lignite , rice husk, sugar processes. The primary issu e to be conside red is the risk (if an y) to th e wate r quality of all Table 1: Oxidants for Taste/Odour & Toxin Removal three dams arising simultaneously from a combination of catchment activities and Oxidant Oxidising Potential Effectiveness in Removing Effectiveness in Removing adverse weather conditions such as sto rm Taste and Odour Algal Toxins f!) / V events bringing in nutrients, pathogen s Chlorami ne 0.75 Ineffective In effective and other contaminants as well as Oxygen 1.23 Limited Limited d rought conditio ns favouring cyan obacChlorine 1.36 Reasonable Very effective with some terial deve lopment and dominance over toxins, little effect on others Potassium other algal types. permanganate 1.50 Reasonable Some effect In lig ht of recent events, it is obvio us Hydrogen peroxide Negligible 1 .78 Negligible to conclude that Cooby, P erseverance and Chlorine dioxide 1.91 Good (except MIB and geosmin) Good C ressbrook dams are at in creasing risk of Ozone 2.07 Good Very good cyanobacterial blooms despite the catch-

22

WATER JANUARY / FEBRUARY 2000


WATER

,oo~-- - - - - - - - - - - - ~

WOOif

Woco'Coa,1

Coal

Cool

Ccconut

Ccconut

Coal

Ccconut

Ccconut

(Bl

!Al

(CJ

(El

(0)

lFJ

lEl

tD)

tFJ

Woc»'Coll (A)

Vlood (B)

Coli!

Coal

Ccconut

Ccconut

lCJ

tE)

ID)

(FJ

Figure 3a: MIB Remova l (Spike 250 ng/L & 30 minutes contact time)

Figure 3b: Microcystin Removal (Spike 20 ng/ L & 30 min utes contact time)

Figure 3c: Geosmin Removal (Spike 250 ng/L & 30 minutes contact time)

cane and co conut sh ell. T he o rgani c contaminants are adso rbe d on to the su rface or into the po res o f the ca rbon. Th us the carbon has a limited life and m ust be rege ne rated o r repla ced upon exha ustion o f aU the adsorptio n sites. A ctivate d carbo n is co mm e rcial ly ava ilable as pow dered ac tiva ted ca rbo n (PAC) o r gra nular activate d ca rb o n (GA C) .

Simultaneous dosing o f alum and PAC y ie ld e d low conta min a nt r e m o va l e ffi cie ncies.

additio n th e positio n in th e process train is signifi cant: GAC w oul d have longer life as a te rtiary filt er than as a primary filte r. Bed li fe is also affected by th e type o f GAC , w ith b e tte r pe rform a n ce achieved w ith t he w ood- and coalbased GAC com pared to coco nut GAC . R ege n e ra ti o n of GAC is v ia b le, ho weve r at present the re are no regene ratio n fac ilities in Australi a available for GA C used in potable wate r treatm e nt. C u rrently, GAC has to be repla ced by new G A C follo w ing exha ustio n. Figu r e 4 p re se n ts t h e r e mo val e fficiency o f M 1B usin g GA C against th e

PAC Dosing Rece nt ben ch sca le and pilot scale tes tin g was unde rtake n by H un te r W ater A u s tralia , (B a ile y et.al I 999)i o n Grahamstown raw water to in ves tigate th e effectiven ess of PAC dosin g fo r a raw w ate r spi ked with M lB , ge osmin and algal tox ins. Graham sto w n is th e primary w ate r sou rce in the Hunte r and e xte nsive tes ting with PAC w as undertaken in respon se to an M 1B eve nt in 1998. Some supple me ntary jar restin g has also bee n undertake n o n som e o f the Too woo m ba catc hme nts. Th e PAC produ cts teste d in th is study include d th e rma ll y ac tiva t ed wo o d , c he m icall y ac ti vated w ood, th e rmally ac ti vated coal and th e rma ll y activated co co nut from a n umbe r o f supplie rs. For MIB , mi crocystin and DOC tests, PA C was dosed into the spiked raw w ater prio r to alum flocc ul atio n. Th e initial spiked conce ntrati o ns o f M IB , microcyst in and geosmin w ere 250 ng/ L and 20 u g/ L and 250 n g/ resp ectively . In th ese tests, PA C was dosed into closed vessels for selected contact times. Th ese and oth er stu dies indica te that th e effec tiveness of PAC dosin g is dependen t on a numbe r o f factors in clu din g the background characte risti cs of th e raw wa ter NOM , th e typ e o f PA C used , t he conta minant be ing targeted , th e P AC dose rate, con tact tim e and mi xing, .( i. e. it is both site specifi c and co ndi tion specifi c) . It is esse ntial that both the equili brium and ki ne tics o f PAC for a pa r ticular w ate r are unde rstood. W ork u n d ertaken also ide ntifi ed th e im portance of the PAC dosing lo cati o n in opt i mi sing PAC p e rforman ce .

GAG Filter Adsorbers GA C is incorpo rated into a filter bed w ith parti cles gen erally in th e size range o f co nve ntio nal media (0.5 to 2 .5 mm). T he em pty bed conta ct time (EB C T ) is typi cally 5 to 15 m inu tes and th e fi ltration rate is typically be tween 5 and 18 111 / h. Th e effec ti ve service li fe of GAC fo r organic co ntaminant re mo va l is primaril y re lated to the startin g le ve l and target leve l fo r the co ntamin ant o f co ncern. In

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WATER

removing cyano bacte ria so m e to xins , but on ly thos e w i th toxin as ozonation rapidly h i g h molec u lar wei g hts (> 1000). • 12 min EBCT destro ys tox ins and BAC Nanofiltration and reverse osmosis are prov id es a seco nda ry able to rem ove most taste and odour • 6 min EBCT barri er for toxin rem oval co mpounds and algal toxins. by bio logical action and N ano fil tration effectivel y re mo ves adsorption . particles of m o lecular weight greater Full scale operation of than 200 . T he molecular · weight of th e ozo ne/BAC process toxins are 300 and 500 for ne urotoxins 80% in Europ e and pilot and cyli ndrospermopsin and > 1000 for studies in Australia ha ve microcystin and nodu]arin. Nanofiltration w as found to provide shown th e process to be 70% h ig hl y e ffec ti ve . Th e complete removal of mi crocystin while stud ies have shown the recent studies (Panglisc h et al, 1996) foll owin g: w ith Microcystis 11er11gi110s11 u sing a labora600/4-+-----.----r-- - - . - -- ---r----r- ~ co mpl ete removal of tory cell con taining a single me mbran e 0 2000 4000 6000 8000 10000 cya noba cteria toxins; showed that both mic rofiltration and at least 50% redu ction ultrafiltration were effecti ve in removing Bed Volumes in chlorine de mand , algal ce lls intact with virtually no release reducti on in bacterial of microcystin. Figure 4: MIB Removal using GAC R.ece nt developments in the use of grow th potential of w ater number of bed volumes processed . It is and improved m icrob io logica l resul ts at immersed membran es with PAC for clear that after a fi nite period time, lower chlorine levels, pesticid e rem oval in Europe show good which may be only a few weeks, the bed • large red uction in disinfectio n byprod- promise for the treatm e nt of algal toxins is no longer capable of the degree of ucts (T HM's), and taste and odour compo unds. organic contaminan t re moval required. • extension of GAC life (indefinite if no A number o f issues re main , however, For example, if 90% Mll3 removal is micropollutants) and with th e use of membrane processes required to meet taste thresho lds then • removal of ozo nation byprodu c ts. including costs and rej ec t streams . A on ce 5000 bed vo lum es were processed St udies by Hunter Water Australia at substa ntial waste strea m heavily loaded then the GAC filter would no lon ger be Grahamstown showed that ozon e/ BAC with toxin , high in salts and othe r able to re mo ve M Il3 to the desired level achi eved removal of cylindrospe rmopsin min e r a ls is produc e d from th ese despite the fac t that there is still considto < l ~1g/ L at an ozon e residual of processes and wou ld ha ve to be di sposed erabl e unspe nt Mll3 removal capability 0 .15 mg/ L. C urren tl y more detail ed o f in a suitabl e mann er. The cost of remainin g in the GAC. Similar results work is bein g und ertaken at Armidale , these processes is like ly to be more N SW into the effecti ve ness of the ozone econom ica l w ith future d evelopm ents were obtain ed with GAC using microcystin. It is important to note that this BAC process to re mo ve saxitoxins, and may beco me viable options in th e futur e. pilot plant work w as undertaken using geosmin and MIB. GAC afte r coagulation and settling. Membrane Processes COSTS Ozone/Biological Activated Carbon Membran e systems ava ilable for water In vestiga ti o n s at T oowoo mba , at (BAC) treatment include micro filtratio n , ultraGrahamstown in the I---I unte r and at other Ozone/ l3A C is a tertiary pro cess that filtration, nanofiltration and rev e rse sites ha ve indicate d that the costs of treats fil tered water befor e post chemi cal osmosis. Microfiltration can filter out various trea tm e nt options are highly trea tment. Th e process in volves ozonat- al ga l cells but not toxins. Ultrafiltra tion d e pe nded upon t he fre qu e ncy and ing w ater and passing it through GAC ca n remove dissolved organi cs, includin g duration of o rganic co n tamination filte r beds, as shown sc he mati cally in Figure 4 . Biological growth fro m the nacural bacteria in th e wa ter is established in the pores of th e GAC. Ozone Backnas h waste water B.tckuash w.1stc waler Ozone breaks down co mpl ex organic Contact Chamber compounds present in the water into simple forms w hi c h are more rea dil y ava ila ble fo r the mi cro-orga nism growth Firs t Sta ge Second Stage on the l3AC. The adsorpti ve c hara cte rl;'iltration Filtruti on istics of the GAC o nl y play a minor role in re mo va l of organics from water so that Filler Sand llAC the bed does not norma ll y req uire Sand regeneration. Th e ozo ne/BAC process is wi dely used in Europe fo r the removal of pestic ides, o rgani cs, oxidation byprodu cts, IJackwn sh Vi lfcr ed Filtered Uackwush and taste and odo ur compounds. It is water water "'atcr water also used for redu c ing regrowth po ten Ozone tial of water, red ucing chlorin e dosing, and redu cing disinfection byprod ucts formation . It is extremely effective in Figure 5: Ozone/BAC process schematic

i

24

WATER JANUARY/ FEBRUARY 2000


WATER

e vents. PAC has a high op erating co st and low capital cost and he nce is suitab le fo r water supplies that experie n ce in frequ ent and short du ratio n con tami nation events. On the other ha nd it has been d e m on stra te d fo r c a tc hm e nts th a t e xpe rie nce fr equent or o rganic co ntam ation eve nts of long du ratio n that p rocesses requi ring significant ca pital ex pe ndi tu re, su c h as ozo ne B AC , b ecom e in creasingly attractive. Ozone B AC offers a n umbe r o f oth er advantages inclu ding redu ctio n in c hlorine d em and and improve me nts in other aspec ts of wa te r qua lity that need to b e fac tored into the o ve rall econo mi c assessm ent.

Development of a Strategy T he de velopme nt of a stra tegy for the treatme nt or contro l o f spo radic orga nic co nta m inatio n o f a drinkin g wate r su pply in volves the initiatio n of short a n d lo ng- te rm ini tiatives. T h e key process for develo pin g the st rategy involves the fo llowing steps, as sho w n 111 Figure 6: • ide ntify co nta mi nants of conce rn R..i sk o f E x po sure to • assess C ontaminants including th e frequ ency a n d du ratio n o f o rga ni c co ntam inati o n e vents. • estab lish eval uatio n cri teri a m ay • investiga te treatme nt o p tio ns invo lve laborato ry, pilot o r desk top studies, • eva luate and co st treatme nt options, • impleme nt preferred stra tegy T he risk assess me nt stage is impo rta nt fo r dete rmin ing the o ptimum app roac h fo r dealing with o rgani c con tami na ti on . T h is is im po rtant w he n d ea li ng wi th m ul tiple catc hm en ts o r wh e n d ecisio ns n eed to made rega rding allo catio n o f resou rces betwee n catc hm en t initiatives a nd treatme nt infrastru cture. Lt is critica l, howeve r, that the existin g strategy is re viewed in detail alon gs ide th e abo ve p r ocess w ith fo c us o n m o nit o ri n g programs, catc hm e nt manage me nt and e m e rg e n cy r es p o n se pr oc edur es . F u rth er to this the preferred strategy mu st be co ntinuall y re viewed to ensure th at the required level of p ro tection is in p lace to e nsure a safe and palatable wate r supp ly.

Conclusion H unter W ate r Au stralia has esta blish ed a ri sk-based strategy for Australi an commu n ities to deal with the th reat of o rga nic contam inatio n eve nts in their ca tc hm ents. R esponse to suc h threats necess itates a m u lti- fa ceted approac h . T h is in clu des imple me nting a range o f

/

Strategy Development

t Identify contaminants of concern

Review operational strategies

~

Continual Review Process

t Establish evaluation criteria

'

Review Protocols • Monitoring • Catchment management • Emergency response

~

t

l

Investigate t reatment options - laboratory and desk top studies

Improved information on event frequency and duration

t Evaluate treatment options

t Implement preferred strategy

/

Figure 6: Generic Organic Removal Strat egy

initiati ves to wards be tte r man age me nt o f water storages and th e asso cia ted ca tc hm e nts as well as selec ting a treatm e nt strategy fo r remova l of o rganic co n tam inan ts fro m the wa te r strea m . Th e option se lected fo r treatme nt o fte n depe nds signifi can tl y o n the frequ e ncy a nd du ratio n o f o rga nic co ntam in ant b looms in the catch me nt. Fo r examp le, for c at c hm e nt s t h a t e xp e ri e n ce pro longed o r frequ en t o rgani c co n ta mi n a ti on , o zon e B AC ma y be t h e prefe rred optio n . Fo r catc hme nts that are less affec ted by o rgan ic conta min ati on , PAC may be a more viabl e and cost effective altern ative. K no w ledge in the use o f PAC is critical in ensu ring dose rates are min im ised . B ecau se o f the diffe ring le vels o f comp eting NOM in each catch me n t site specifi c testing is recom m ended .

Acknowledgements The authors wish to acknow ledge the co n tri butio ns o f K e vin Fla naga n o f T oo woo mba City Cou ncil and Al an T ho rn ton of Hu nter Wate r Corporatio n fo r their co ntri bu tio ns to th e work undertake n.

References

Falconer, I.R.. (ed) ( 1993) A (~al Ti,xi11s i11 Seq{ood a11d Dri11ki11g Water. Academic Press, London Gutteridge, Haskins & Davey ( 1990) Cooby Da111 R ecrea 1io11al S tra teg y G I-I D R e port to T oowoom ba C ity C ouncil, April , 1990 Jones, G ., M inato! , W., Craig, K., N aylor, I~ . 1993. R emoval o f Low Level Cyanobacterial Pesticide T oxins fi-0 111 Drinking W ater Using Powered Activated Carbon and Granular Act ivated Carbon and C hlorinatio n - R esults of Labo ratory and P ilot Plan t Studies. A 11stralia11 vVatcr & Was1e111ater Associnrio11 15th

Federal Co11ve11tim1. Panglisch, S., C how C ., M o le J .Drikas M ., Burch M. and G imbel R . ( 1996), Me111b ra11e

Fi/tratio11 for Removal

,if Cya11obaaerial

Cells,

Australian Wate r Q uali ty Centre, Salisbu1y, South Australia, International M e mbrane Science and T echno logy Con fe ren ce. T oowoomba C ity Counci l ( 1998) Prored11re fo r

111011i1ori1(!/ da111 111ater q11alir y Q P- W WO-0 15 Versio11 I. 0 Marci, I 998. T oowoo111ba C ity Cou ncil ( 1998) Proced11res for bl11egree11 a(~ae PQP- WWO- 01 6 version 1.3 M ay 1998 Velzeboer, K., Drikas, M ., D onati, C., Burch, M ., Steffensen, D. 1995 . T he l~ e111oval of Algal Cells by Alum Flocculatio n, A11stmlia11 Water &

vVasreivater A ssocinrio11 16th Federal Co1111e11tio11.

Authors

Bailey D M , Bowen B, Good win LM , Procter LG ( 1999) "An O rgan ic R.e111oval Strategy for Graha111stown " A 11strnlia11 l1Vnrer & vVaste111nrer

Associniio,1 18th Federal Co11ve11tio11. Falconer, I.R. ., R.unnega r, M ., and H uyn, V. 1983. " Effectiveness of Acti vated Carbon in the R.e111o val of Algal T oxin from Potable W ate r Supplies: A Pilo t Plant Investigation"

·J0tft Federal Co11vC11tio11 of the A11strnlia11 Water a11d Wastewater A ssociatio11 .

Peter Dennis and Darren Bailey are process e nginee rs w ith H unter Wate r Australi a Ltd .w hich provides specialist o peratio ns and ad visory services to the water industry. Bruce Cole is the se n ior bio logist with H un te r Water Corporation , w hich suppli es water services to the lower Hun ter Valley.

WATER JANU ARY/ FEB RUARY 2000

25


a

WASTEWATER

A ROLE FOR SUPERCRITICAL WATER OXIDATION A Shanableh and N Crain Abstract The Supercritical water oxidation (SCWO) p rocess provides effective destruction of o rga ni c wastes and sludges, utilises a totally enclosed treatment facility, and meets regulato ry requirements. The process is econom ica lly competitive and environmentally so und. Recent co mmerc ialisation of this technology in the United States and J apan has transformed innovati ve SCWO treatmen t into rea lity . The SCWO process is capabl e of achieving excepti onally effici en t trea t ment results, producing high qua lity efflu en ts and disposable residuals . The avai lable body of knowledge supports the design of full-scale SCWO waste treatment systems. The system ca n be designed to accommodate the vari ations in wastes, tem peratures, residence times, and types of oxidants. Difficulties associate d with corrosion and so lids 111anageme nt can be 111ini111ised through proper waste c h a racterisation and pretreatment evaluation s.

Introduction Extensive researc h conducted du rin g the last two decades (Mod elI et al. , 1982; H elling, 1986; Sha nableb and Gloyna, 1991; G loyna and Li, 1998) demonstrated the high destructi on efficiency of haza rdous organ ic wastes and sludges by supercritical water oxidation (SCWO). In the early 1990s, the research efforts broadened to consider the engineering aspects of process development and design (McBrayer et al. , 1993). In May 1994, the first com mercial superc ritica l water ox idatio n (SCWO) fac ility was com missioned to treat a mi xture of hazardous liquid wastes generated by the T exaco (Huntsman) C h emical Compa ny in Austin , Texas (McBrayer, 1995). The breakthrough was significant no t only because the facil ity was the first of its kind, but also because the responsible C ity and State Envi ronmental Agencies in T exas readil y licensed the process confir111ing satisfaction with the effectiveness and environm ental so undness of the pro cess fo r air emissions and effiu ent disposal. In 1996, the facility won the T exas Governor's Innovative Treatm ent Aw ard. Research and developm en t has

26

WATER JANUARY /FEBRUARY 2000

continu ed o n an in creasing scale in the United States, J apa n , Australia and a number of European countries. Wet oxidatio n of o rgan ic compounds at temperatures below the criti cal point (374°C) is relatively slow and achieves in co mpl ete orga ni c co n ve rs ion (Zi111merman, 1958; T eletzke, 1964; Li et al. , 199 1). H owever, wet oxidation at temperatures above the criti cal point (SCWO) is relatively rapid and potentially complete. Th e in itial researc h effort involving SCWO fo cused on developing an effective waste treatment proc ess capable of achieving virtually complete destru cti on (greater than 99.9999%) of th e o rganic componen t o f waste stream.s. The process originally was viewed as an alternative to incineration , offe ring a mo re feasible an d e n vironm e nta ll y friendly way of treating dilu te organ ic

waste streams. However, extensive treatability studies confirm ed that the process was suitable for treatin g a wid e range of organi c waste streams, convertin g co mplex orga ni c molecules into carbon dioxid e and water (G loyna and Li, 1998). The studies confir111ed that unlike incineration, the SCWO process was achi evable in an enclosed treatment facili ty, thus no harmful air emissions were detected. Th e early indicati o ns in terms of the technical feasi bility of the pro cess were favourable and encouraging, and as such, the concept generated inte rest among research e rs, industria l observers, and generators of hazardous wastes. Since the ea rly 1990s, the SCWO resea rch emp hasis has shift ed from co ndu c ting treata bility st udie s to technolo gy development and optimisa-

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ti o n of design and operations (M cBrayer e t al. , 1993) . The process development efforts have fo cused on syste m design and n1odellin g, solids separati on , h eat recover y, process control, safe ty require m ents, m a te ria ls ev alu a tion a nd co rros io n , e rosion, and effi uen t and ash disposal re qu irem ents. R esearchers have ide ntifie d soli ds separati o n , co rro sio n and pro cess co n tro l as a reas req uiri n g addition al researc h and d eve lopme nt (Glo y na and Li , 1998) . T rea tm e nt optimi sati o n efforts are fo c use d on pro cess m o d e lli n g, c ata lys i s, a n d b e ha viour of inorga ni c substan ces. C urre nt resea rch efforts are also foc used on identifyin g o pportunities for resource reco very, particularly heat, wate r and inorganic materials, and searc hing fo r n ew process app lica tion s.

Technical Background Th e SCWO trea tme nt co ncept is based o n th e un iqu e c hara c teristics o f supe rcriti ca l wate r (SC W ). Accordin gly, th e m ost signifi ca nt c harac te ri stics o f sew and pro cess d evelopm ent are d isc ussed in th e fo ll owing secti o n. Th is d isc ussion includ es a desc ription of the m ec hanisms in volved in waste destru ction using the SCWO process and a summary o f se lected treatability resul ts. Supercritical Wat er

W ater becomes a supercritical fl u id at te m peratu res and pressures abo ve th e

Table 1: Selected properties of Property and Unit s

Temperatures ('CJ Pressures (MPa) Dens ity (g/ ml) Viscosity (µP) Kw (Water Dissociation) Static Dielectric Constant Salt Sol ubility (mg/ kg) Na2SO• NaOH Si02

PbO NiO NaNOJ NaHCOJ NaCl Mg(OH)2 Li NOJ KO H KN0 3 K2HPO• Fe2Q3 CuO CaCOJ Al2Q3

cri tica l po int (374.2"C and 22.l MPa). Superc ritical water ma y be viewed as a transition Hate betweeu the liqui d and gas phases. Within the critical zone, the li quid and gaseo us phases m erge resulting in one phase , or supercritical flu id. Th e superc riti cal fluid has un iqu e charac te ristics, som e o f w hich are highly useful fo r orga nic waste hydrolysis and oxidation. Se lecte d p ro p e rt ies of SC W are presented in T able 1. O xygen is co mpl etely misc ible in sew. sew also has a high abili ty to dissolve non -polar o rgan ic m atte r and fac ilitate mass tran sp o rt of di ss ol ved matter. Beca use o f low viscosity (Table 1) and high d iffusivity, sew can more easily penetrate porous material, suc h as sludges, and destroy orga nic solids. T hese characteristi cs of sew result in rapid oxidatio n reac tions that are no t hindered by m ass tran sfer li mitat ion s. R apid reactions requ ire smalle r reac tio n vesse ls. On the other hand , the lo w de nsity o f sew with in ge ne ral operati ng pressure o f about 22-2 5 MP a re du ce s th e res ide nce time ava ilab le fo r reactio n inside reaction vesse ls. T he low po larity and low diel ectric co nstant o f sew result in rapid sa lt fo rmatio n . Io ns are in effect " hydropho bic" in sew, preferring to leave the ca rrying medium. T he polarity of SCW dec reases w ith dec reasing sew de nsity and as suc h , th e solu bi lity of salts dec lin es

w ith d ec reasi ng SCW density . For exampl e, the solu bility o f SiO2 declines fro m 2,600 m g/ L, at S00"C and lO0 MPa (D ensity 0.54 g/ mL), to 250 mg/ L, a t 500 "C a nd 28 MP a (D e n sit y 0 .10 g/ rnL). T h e low viscosity and low density of sew allow rapid separation of sa lts and o the r suspen ded matter. O n the o the r hand, the fo rmatio n of sa lts in sew and th e ac compan yin g solids de p osit io n present a challe nge w h en the separatio n of suc h solids is not the main treatm en t o bjective. Th e so lids, incl udi ng formed sa lts and o th er suspend ed m atte r, may eithe r stick on reacto r wa lls, reducing the heat exchange capacity, o r deposit in the reac tor syste m , plu ggin g imprope rly design ed co mpo nents. Sup ercritica l wa te r is an excellent thermal e ne rgy carrie r, havi ng spec ifi c heat capacities that are seve ral o rde rs of magnitud e h igh er than those of liqu id wate r. As an excell e nt heat ca rri e r, SCWO allo ws the maximu m recovery o f heat liberated du ri ng th e o xidation o f o rga nic waste .

Waste Destruction Mechanisms Co m p le x o rga n ic m atte r typically undergoes two major reac tio ns during SCWO: hydrothe rmal deco mpositi o n and oxidatio n. H ydrothermal deco mpositio n resu lts in th e formation of simple r o rgani c matter, whil e ox idation results in

sew Conditions

25 25 25 25

MPa, 3 75 ' C MPa, 450' C MPa, 375'C MPa, 450'C sew (Undefined) sew (Undefined) 27.4 MPa, 3 50'C 30.0 MPa, 4 50'C 28.3 MPa, 400' C 2 5-30 MPa , 4 50 ' C 28 MPa , 500' C 100 MPa, 500 ' C 2 8 MPa , 500' C 100 MPa, 500' C 2 7 .6 MPa, 4 50-500 ' C 29 .8 MPa , 509 ' C 30 .0 MPa, 500'C 24.0 MPa, 440 'C 2 4.7-27 .7 MPa , 4 33' C 22.1-2 7 .7 MPa, 500' C 2 4.8-27 .6 MPa, 4 75' C 26.8-29.5 MPa, 4 50'C 100 MPa, 500 'C 25-31 MPa, 450-6 2 0 'C 2 4 MPa , 440' C 100 MPa , 500 ' C

Value

>374 .2 >22.1 0.507 0 .109 597 31 0 10·21.6

References

5

Marshall and Frantz (1987) Gloyna and Li (1998)

70 ,000 0.02 25,000 55-160 250 2 ,60 0 6 84 20 540-991 86 200 0 .0 2 433-1,175 60-331 275-402 <7-17 90 0.01 0 .02 1 .8

Ravich and Borovaya (1 964) Martynova (1976) Urusova (19 7 4 ) Martynova (1976) Matson and Smith (1989) Yokaya ma et al. (1 989) Yokaya ma et al. (1 989) Matson and Smith (1989) Dell 'Orco et al. (1992a) De ll 'Orco et al. (1 992a) Martynova (1 9 76) Martynova and Smirnov (1 964) Dell 'Orco et a l. (1 992a) Wofford (1994 ) Dell' Orco et al. (1 99 2a) Wofford (1994) Mat son and Smith (1989) Martynova (1976) Martynova and Smirnov (1964 ) Matso n and Smith (1 989)

WATER JANU ARY/ FEBRUARY 2 000

27


WASTEWATER

/\ ~'---

RH + HO•~ R• + H 20 R• + 0 2 ~ ROO Ro o · + R H ~ R· + R OO

A = Initial Complex Organic Matter, Including Organic Solids B = Hydrotherma l Decomposition Products

),

),

_ ____,/

C = Intermediate Oxidation Products D = Final Oxidation Products

Figure 1 : Simplified hydrothermal oxidation model

th e fo rmatio n of oxygena ted interm ediates and fin al oxidatio n products. The general SCWO reactio ns may be represe nted by the reaction model shown in Figure 1. Starting with a waste material containing a m ix ture o f simple and complex organic matter (A), the o rganic material undergoes hydroth ermal decompositio n and oxidatio n formin g simpler organic matter and intermediate products (B and C) . Simultaneously, oxidatio n of primary compon ents of the o riginal organic material can lead directly to the form ation of end products (i. e., carbo n dioxide and water). Similarly, oxidatio n of the primary hydrothermal decomposition and intermediate oxidatio n products results in th e formation of end products (D). B oth hydrothermal decompositio n and oxidatio n liberate th e heteroatoms prese n t in the organi c w aste . T h e ultimate fate of th e heteroatoms depends on the reactio n conditions. H eteroatoms su ch as P, S, and C l are raised to their

highest oxidation state. The fa te o f nitrogen ho wever is m ore complex. Nitrogen products may include ammonia, nitrogen gas, nitrates, and nitrites depending on the original fo rm of nitrogen in the waste and the reaction condition s such as temperature and pH. Th e overall SC WO reaction fro m a waste material (A) to the end pro du cts (D ) 1s represented by Equation 1. C H NOPSCl + 0 2 ~ C O 2 + 1-1 20 + Po/- + er + so/- + NH/ + N 2 + N02- + N0 3- + H eat (1) The m aj o r reactio n path ways in SCWO appear to in volve free- radicals (Emanu el, 1967). ln the process, an orga nic radical (R •) reacts with oxygen to form an orga nic peroxy radi cal (R.oo·) w hich abstracts a hydroge n ato m producin g an organic hydroperoxide (RO O H) and a new radical (R • ). The mechanism is depicted in Eq uatio ns 2 through 4.

Th e m ec h ani sm d ep i c t e d 111 Equ ations 2 thro ugh 4 describ e the fo rmatio n of ROO H fro m RH in the fo llo wing sequence: RH ~ R..Oo• ~ RO O H. H ydrothermal decompositio n is re spon sibl e for brea king large and c omplex orga ni c c omp o unds (R H ) containing hi gh numb ers of carbon ato ms into smaller organic compounds w ith fe wer organi c ca rbon atoms. Ace tic acid (C H 2COO H ) appea rs to be o n e o f the most thermall y resistant ROO H intermediates. Co n versely, fo rm ic acid (CH OO H), as com pared to acetic acid, is detected in m uch small er quantities. Destruction of Organic Waste Streams Exte n sive tre at ability studi es condu cted at The University of T exas at Austi n (U T) invol ving pure o rganic compounds, complex organic wastes, and both industrial and municipal sludges have confirmed that the SCWO process is capable of virtually achieving complete destruction of the organic components of wastes. Such studies were conducted using laboratory-sca le and pilot-scale reactor systems. Examples of these treatability results are presented in T able 2. T he data indicate that acetic acid is one of the mo re refractory organic compo unds and was fo und to be a co mm on intermediate o f incomplete oxidation.

Process Development Gloyna and Li (1998) summarised the

Table 2: SCWO destruction efficiencies of selected waste streams using excess oxygen Waste Material

Reactor Type

Time min

T'C

I nfluent mg/ L

Re mova l %

Basis

Batch Batch Batch Batch Batch C. Flow C. Flow C. Flow C. Flow Batch Batch Batch Batch Batch Batch Batch Batch Batch Batch Batch Batch

5-10 4-8 2-8 5-10 5 1.8-3.4 0 .8 0.5 1 5 3 1.2 4-5 2 1-3 2 5 2 5 1-5 2

450 400-450 400-500 500 450-500 400-450 490-530 450 400-500 450-500 450 450-500 450-500 450 410-528 450 450 400 400-500 450 500

30,300 14,200 170 108,000 36,200 993 69,100 10,000 18,400 6175 1000 10,400 300-1000 1000 84-200 1000 5140 500 500-1000 1830 200

98.7-99.8 95.1-99.4 92.4-9 4.6 99.8-99.9+ 99.9 97.6 99.5-99.9 >99.99999 98.5-99 .7 97.3-98.8+ 99 .9+ 8 7-94.9 99.7-99.9+ 99.9+ 83-99.5+ 99.9+ 97.3+ 99.99+ 29 .5-97 .6 98.2-99.3 99.995+

COD COD COD COD TOC TOC COD Org* Org* Org* Org* Org* Org* Org* Org* Org* Org* Org* Org* Org * Org *

Industrial Sludge 1 Municipal Sludge 2

Contaminated Agricultural Soil3 Paint Wastes 3 Electric Power Plant Waste3 Indust rial Waste (Nylon Manufact uring)3 Pulp and Paper Mil l Sludge4 Warefare Agent (GB, VX, Mustard)5 Nitrotoluene 3 2-Butanone 3 p-Chlorophenoi 3 o-Cresol 3 2,4-Dichloropheno3 Diethylene glycol Diethlether3 2 ,4-Di nitrotol uene3 Ethylene glycol 3 Methyl ethyl ketone 3 Pentachlorophenol 3 Pyridine 3 Trichloroethylene3 2,4,6-Trichloro phenol3

1Shanableh (1990); 2Tongdhamachart (1991); 3G!oyna and Li (1998); 4 Blaney et al. (1995); 5Downey et al. (1995) * based on measuring the treated organic compound (Org).

28

WATER JANUARY / FEBRUARY 2000

(2) (3) (4)


WASTEWATER

Gas

+

Liquid/ Gas Separator

Liquid Effluent

Heated Fluid Heat Exchanger Preand Cooler Heat er

Heat Exchange Fluid

t

Figure 2 : General process arrangement

key design co nsidera tions fo r a su ccessful SCWO system. T hese in cl ude: infl uent pre trea tm e nt ; e ne rgy co nsideratio ns; mate rials; treatme nt co nditions; effl ue nt handlin g; and ash disposa l. Th e waste c h aracteristics and treatment objective a re important considerations in te rms of mate rials se lection, ene rgy conside rations, and p ro cess co nfig u rati on. Treatment to achieve comple te oxidatio n or intermediates recovery req u ires tre atability testing to select the most sui table range of reactio n temperatures , press ures, residence times, and oxidan ts. Since the SCWO reaction is exotherm ic, oxidised o rgan ic waste may ge ne ra t e a significant amount o f h eat. E co no mi c designs require a sufficien t co nve rsio n of the orga ni c m atter to sustain the desired reac tion te mperatures. Fo r dilu te wastes, it may be necessary to ad d external heat or an inexpensive, hig h o rganic co ntent waste supplement. For co n ce ntrated orga nic wastes, the syste m des ign must accomm odate the increased h eat gene rati on by appropriate hea t exchange, i nflu ent dilution or strategic inject ion of th e ox idant along the reaction zone . I<. .ecovering th e effiu e nt at am b ie n t temperatures and press u res re quires cooling the treated waste, wh ich is typ ica ll y ac hi eved t hrough h eat exchangers, includin g feed pre-heate rs and steam ge ne rators. An exa mpl e of a SCWO system is prese n ted in Fig ure 2. The sys te m e mploys the fo llowi ng sequen ce o f hot zo n es: pre-hea ter, reac tor, solid-liq uid separator, and coo lin g/ energy rec overy exc hanger. T he pre-heate r utili ses some of the energy in the effl uent to heat the influe nt. P reheating minimises the size of th e SCWO reaction zone and the reby e n sures rap id reac tions with the oxidant. Introduction of the oxidant into the pre h eated waste stream causes a rapid rise in . tem peratu re and an aggressive ox idisin g environment with in the reactor.

The combination of an aggressive oxid ising e nvironm ent, the presence o f halogens and ex tre me pH flu ctuations ca n lead to rap id m etallurgica l degradation . Similarly, the relatively lo w density and in creased velocity of th e fl uid in side the reactor influ ence erosio n and corrosio n . Th e low density in fl u ences both res ide n ce tim e an d so lid s handling .

Therefore, ca reful consideration must be g iven to reaction temperature an d residence tim e, overall flu id characteristics, and material selection. The heat recovery units are particu la rly susceptibl e to scaling and corrosion. The corrosio n pote ntial in heat exchan gers is e nhan ced because of the fo rmation of mi neral ac ids created fro m the release of heteroato ms during the SCWO reaction (Equ ation 1). As a resul t, scali ng and corrosio n are a maj or design co nsidera tion for heat exchangers. Pressure co ntrol and let- do w n devices are particularly susce ptibl e to erosion. Suspe nded solids in treated efflu ents ca n be co m e abra sive a t high velocities . P ress ure let- down devices, such as throttl ing valves, experience a dramatic drop in pressure as liquid is released into the amb ient e nvironment . Gases contained in the efflu e nt undergo large expansion du ring th is release. Th e release and expansio n of gases pro duce high exit velocities. Erosion of let-down devices may res ult in wide pressure fl uctuations and significa nt pressure drops.

WATER JANUARY / FEBRU ARY 20 00

29


WASTEWATER Material Selection T he high temperatures, availability of Ox')'gen , extreme pH, and prese nce of inorganic species, such as halogens, resu lt in a highly corrosive SCWO environm ent that can rapidly degrade materials. This motivated studies aimed at evaluating corrosion mec hanism s and identi fying materials that display acceptab le corrosion rates under SCWO conditions. T wo approaches have been u ndertaken by researchers to in vestigate corrosion in SCWO environments (Gloyna and Li , 1998): (a) exposing materials to various corrosive waste streams under SCWO conditions, and (b) investigating the corrosion potential through m easuring p H , el ec troc h emi cal potentia l, and thermal diffusion of electrolytes. Both approaches have resul ted in the accumulation of a wealth of corrosion information, suitability of available materials, and potential corrosio n m echanisms. T he severe oxidisin g en viro nment coupled with the variation of possible heteroatoms in wastes makes the selectio n of a reac tor m aterial diffi cult . For example, platinum exposed to mineral acids has shown reasonable resistance (i.e., less than 100 mil/year) to corrosion at temperatures in the range of 450-550°C; however, reduced resistance at temperatures near the critical point. On the other ha nd , titanium alloys have shown reasonable corrosion resistance for mineral acids near the critical temperature. The most suitable materials for SCWO reactions are expensive and usually lack stru ctural integrity. H owever, the acceptable corrosion resistan t materials can serve as liners. A list of selected materials that can tolerate severe SCWO conditions and provide reasonable corrosion rates are presented in Table 3. Solids Separation Positive and n egati ve ions in SCW prefer to combine, form salts, and

precipitate. Characterisation of these salts may be made in terms of th eir fate and transpo rt in the SCWO process. Some salts, Type I, crystallise and form particles that can be fil tered or settled, w hile other salts, T ype II, stick onto exposed surfaces such as the reactor and heat tran sfer units. The salt differentiation is based on melting point and crysta llin e characteristi cs (Valyashko , 1976). Type f salts include: KF, PbF , Cs F, CaC12, Na C l, K 2C O 3 , K3 PO 4 . T ype II salts include: NaF , LiF, Na 2SO 4 , CaSO 4 , K2 SO 4 , Na 3 PO 4 , Li 2CO3, Na2CO3, and C a(O H )z. In addition to salts, suspended solids in the feed may contribute to deposition and scale fo rmation. The low viscosity and density of sew en hance solids sedimentation. H owever, if the ve locity of fluid is kept adequately high, settling may be prevented. The problems asso ciated with settling and scaling may be mo derated through se lec ti ve use of tran sport velocities, additives, and reaction pressures. [n situ solid separato rs have been used with va ryi ng leve ls of su ccess, including v ariou s type s of h y drocyc lones (Laspidou, 1993, D ell' Orco ct al. , 1993), virtual cyclones (Bartru ff, 1998), crossflow filtration (Goema ns et al. , 1995), and gravity settlin g in contro!Jed temperature zones (H ong et al. , 1989) . Other solids management concep ts involve the use of dual o n- line system s. This mode of operatio n permits periodic clea ning of on e unit while maintainin g continu ous SCWO operatio n (Bartruff, 1998) .

Summary Industrial applications in the US and J apan have demonstrated that SCWO can b e economical, environm entall y friendly, and safe . The process is capable of achieving exceptionally efficient treatment results and high quality effiuents. In addition, the process offers opportunities

for energy recovery and possibly byprodu ct recovery of selec ted organi c and inorga nic intermediates. The current body o f kn owledge supports developing full-scale SCWO system designs. Th e major cha!Jenges associated with SCWO process developme n t in clu d e co rro sio n and so lids man agem ent. R esearch has confirmed that such difficulties can be moderated th rough proper waste characterisation and treatability testing.

Acknowledgements During the tim e th is review was prepared, Dr. Abdallah Shanableh was a R esearch Scho lar at the University of Texas at Austin working on research grants sponsored by th e Australian R esearch Co uncil (AR C) on SCWO. Special thanks to Professo r E . F. G lo yna, Bettie M. Smith Ch air in Environ mental H ea lth Engineeri ng, The University o f Texas at Au stin , fo r making avai lable resources necessary fo r completing this technology update .

References 13artruff, C ., Evaluation of a N ovel Method for Separation and R.ecovery o f an Inorga nic Salt fro m Supercritical Water. Presentatio n Mate rial Han douts, SeparatioJ1s R esearcl, Progra111 CoJ1fereJ1cc, T1re U11i11ersi1y ef Texas at A11s1i11, October 20, I 998 Blaney, C. A., Li, L. , G loyna, E . F, and Hossain , S. U ., Supercritical Water Oxidation o f Pulp and Paper Mill Sludge, C hap. 30 in ACS Symp. Ser. 608, h111011atio11s i11 S11percri1irnl F/11ids-Scimce m,d Tec/1110/ogy (H111d1 e11s011, K. W . m,d Foster, N . R., eds.), A 111erirn11 Clie111ical Society, vllaslii11g1011, D C, 1995 Danielson , T. A., Corrosion of Selected Alloys in Sub- and Supercritical W ater Oxidation Environments, i\1/asrer's T11esis, U11i11ersity of Texas, A 11sti11, Texas, 1995 D ell 'Orco, P. C. , Eaton , H . K., R.eyno lds, R . T. . and Buelow, S. J., The Solubility of 1- 1 Elect rolytes in Supercriti cal Water, Los Alamos N ational Laboratory, Publication LA-UR.-92-3359, l 992. Dell'Orco, P. C., Li, L., and Gloyna, E. F., T he

Table 3: Corrosion resistant non-metals, metals and alloys for SCW01 Treatment

Material

Waste Heteroatoms and pH

Sub CWO

Pt, Pt/I r, Pt/Rh Ta Ferralium, G-3O, Ultimet Ti Grade 9

F-, SO4 2-, PO4 3-, pH <2 er, F-, SO4 2", PO43", pH <2 er, so42·, pH <2 NaOH, BO33-, pH 2

Near SCWO

Ti Grade 9 Ti Grade 1 8, SS Grade 316, Pt, Pt/ Ir

SCWO Below 5OO'C

1-6 25 I -718 , Ti Grade 12, Ti Beta-C C276 Pt, Pt/Ir, Pt/Rh Ta Ti Grade 2 Selected Ceramics

c1·, SO4 2-, NaOH-, B033", pH 2

er, so4 2·, pH 2 er, SO4 2-, OH-, 2«

pH « 12, pH 2 c I·, SO4 2-, OH-, 2« pH« 12, pH 2 cI·, OHcr, SO4 2-, PO43", NO2-, NO3", NaOH , 2« pH « 12, pH 2 SO4~, PO4~ , NOi, NO~. 2<< pH <<12 cI·, SO4 2-, PO43·, NO3-, OH-, 2«pH« 12, pH 2, W, OH-

1 Based on data summary presented by Gloyna and Li (1 998) of data from Downey et al. (1995); Latanision and Shaw (1993) quoting Hodge Haynes (1993); Hong et al. (1995 ); Morin (1993); and Kane and Cuellar (1 994)

30

WATER JANUARY/ FEBRUARY 2000


WASTEWATER Separation of Particulates from Supercritical Water Oxi d ati on Processes, Sep. Sri. Ted1110I., 28(1-3). 625-6-1-2. I 993 Downey, K. W., Snow, R. 1-1 ., H azlcbcck, D . A., and Roberts, A. J.. Corrosion and Chem ical Agent Destrnction: R esearch o n Supercritical Water Oxidation of H azardous Military Wastes, C hap. 2 1 in ACS Symp. Ser. 608, l11110vatio11s i11 S11prrcritiml F/11ids-

Scie11rc a11d Ter/1110/ogy (f-111td1l'lls,>11, K. W . a11d l'c>Ster, N. R., eds.), A111erim11 C!,c111iml Society, Washi11gt,m, DC, 1995 Eco waste Technolo gies, Superc ritical Water Oxidation (SCWO) N ews Letter, Ec o waste Technologies Company, Austin, Texas, Volume3,No.1, 1998 Em anuel, N. M. (Editors), Liqui d Ph ase Oxidation of Hydrocarbons, f>ll'lli11111 f>ress, Ne111 Tork, N Y, 1967 Gloyna, E. F., and Li. L. , Waste Treatment by Supercritical Wate r O xid ation. Encyclopedia of Chemical Processing and D esign , J ohn J. M ckctta Exerntive Edit .. Marcel Dekker, l11c., Publisher, Vol. 65. 1998 Goemans, M., Li, L., and Gloyna, E. F., The Se p aration of I norganic Salts from Su p e rc riti ca l Wner b y Cross-Flow Microfi ltrat ion," Sep. Sri. Tcr/11101., 30(7-9), 1-1-9 I - 1509, 1995 H e lling. R. K .. Oxidation Kinetics of Simple Compounds in Supe rc ritical Water: Carbo n Monoxide, Ammonia and M ethano l, Ph i) Dissertation, /\/IT; Ca111bri~~e, MA , 1986. H ong, G. T .. Killi lea, W .. and Thomason, T., M ethod for Solids Separation in a Wet Oxidation T ype Process, US Patl'llt No. 4, 822,497, 1989. Hong. G. T .. O rdway, D. W., and Zilberstein, V. A .. M aterials T est ing in Supercr itical Water O xidati o n Systems, presented at the First /11temntio11al I Vvrksl10p 011 S11perrritiral Water Oxidmio11, J ackson ville. FL. Feb. 6-9, 1995. Kane, R . D . and Cuellar, D., Literature and Experience Survey on Supercritical W ate r Corrosion, C LI /11tematio11al L941079K, July 19, 1994 Lasp idou, C. S., Cyclone Performance for the Separation of Solids from Supercritica l Water Oxidation Efflu ents, ,\laster's Th esis, U11i11l'rsity ~( -frxas, Austi11, Texas, 1993. Latanision, R. M. and Shaw. R.. W .. Corrosion in Supercritical Water Oxidation System s. Workshop Summary Based on a Meeting H eld at M IT , M ay 6-7, 1993, J\IIT-EL 93006, Sept. I 993 Li, L., Chen , P. , and Gloyna, E., Generalised K inetic M odel fo r Wet Oxidation of Organic Compounds, A IC /-/ E Joumal, 37(11), 1687-1697, 1991. Marshall, W. L. and Frantz, J. D .. "Electrical C o nd uc ta n ce M easurem ents of Dilute, Aqueous Electrolytes at Temperatures to 800'C and Pressures to -1-26-t Ba rs: T ech ni ques an d In t erp r eta t ions," in 1-Iydrothemrnl Experi111eutal Ted111iq11es (Ulmer. C. C. and Barnes, 1-1. L., eds.), N ew Yo rk, J ohn Wiley & Sons, I 987 Martynova, 0. I. , S olub ility o f Ino rgani c Compounds in Subcrit ical and Supercritical Water, in f-l(eh Tc111pemt11re, /-/(~/, Pressure Elertrorhe111istry i11 Aq11eous Sol,11io11s, NA CE4, 1976 . Marryno va, 0 . I. and Smirnov, 0 . K., Solu tions of Ino rgan ic Compounds in Supercritical S team, Russ.). h10~e- Che111 ., 9(2), 1-1-5-1 -1-8, 1964

Matson , D. W. and Smith, R.. D. , Supercritical Fluid Technologies for Ceramic-Processing Applications,). A111. Cem111. Soc., 72(6), 871881, 1989 M c l3rayer, R., Li, L., and Gloyna, E. , Research and D evelop m ent of a Commercial Supercrit ical Water Oxidation Process, in

Proreedi11gs cf the I !ti, A 1111ual E1111iro11111wtal 1\,/a11age111£·11t a11d Tec/1110/ogy Co1,Jere11re, f-laz Mat /11tm 1atio11al, Atla11tic City, !\/), pp. 90-111, 1993 . Mc13rayer, R.. , D esig n and Operation of the First Supercrit ical Water Oxidation Facility, presented at the First /11temntio11al l1Vorkshop

,m S11pcmiticnl 111ntcr Oxidntio11, Jarkso1111ille, r:L , Feb. 6-9, 1995 . M odel!. M. , G audet, G., Simson, M. , H o ng, T. , and B iemann, K. , Su percritical Water T est in g Re vea ls N ew P rocess H o lds Promise. Solid 111astcs Mmrnge111e11t, 25, 26-32, 1982. Morin , R.. J ., Ceramics for Corrosion R esistance in S uperc riti cal Water Envi ronm en t s,

Master's T11csis, U11i11ersity Texas, 1993

,if Texas,

A11sti11,

R avicl,. M. L. and 13orovaya, F. E., Phase Equilibrium in the So d ium- W :1ter System at H igh T emperatures and Pressures, R11ss. ). h1o~e- Che111., 9(4). 5 20-532, I 964 Shanabkh, A. M ., Subc ritical and Supercritical Water Oxidation of Ind ustria l, Excess Activat e d Sludge, Ph. D . Disse rtati on , U11ivcrsit y of' Texas, A11sti11, Texas, 1990 Shanable h, A. and G loyna, E .. Supercritical W ater Oxidation-Wastewaters and Sludges. lVatcr Srimrc a11d Ter/1110/ogy, 23 (Kyoto), 389-395. 199 I T eletzkc, G . 1-1 ., W e t Air Oxidat ion, Che111. E11.~. Prog ., 60( 1), 33-40, 1964. T o ngdha m ac hart, C., SupeTcritical W ater Ox ida t ion of Anaerobica lly Digested Mun icipal Sludge, Ph. D . Di sse rtation , U11iversity ,if Texas, A11sti11, Texas, 199 1. Urusova, M.A ., Phase Equilibria in the Sodium H ydroxide-Water and Sodium C hlorideWater Syste m s at 350-550°C," Russ.). Iu01:~Che111., 19(3), 450-454, 1974. Valyashko, V. M .. Phase Equ ilibria in Water Salt Systems-Some Problems of Solubility at Elevated T e m perature and Pressure. In l-1(~/,

Te111pernturc a11d f-1(~/, Press11re Elcrtrochc111istry i11 Aq11()11s Sol11tio11s, NACE--+, pp. 153- 157, 1976. Wofford, W., T he Solubility of Potassium H ydroxide and Potassium Phosphate in Supercritical Wate r, Master's Th es is, U11iversity ,if Texas, Austin, T exas, 1994. Yokoyama, C., lwabuchi, A., and Takahashi , S., Solubility of PbO in Supercritical Water, F/11id Phase Eq11ilibria, 82, 323-332, 1993. Zim m e rman, E . J. , New Waste Disposal Process. Che111. E11,~., 117, August, 1958.

Authors Dr. A. Shanableh is a sen ior lecturer in Environm ental Engin eering, School of Civil Engin ee r in g, Qu ee nsla n d Un iversity of T echnology, 2 George Street, GPO Box 2434, Brisban e, Q ld 4001 , Au stra lia, email: a.shanableh@ qut. edu.au . Dr. N. Crain is a research enginee r, Su percritical Water Oxidation proj ect, Th e Un iversity of T exas at Au stin. WATER JANUARY / FEBRUARY 2000

31


WASTEWATER

TREATMENT OF PHARMACEUTICAL WASTEWATER D Wiesner Abstract

Introduction

Pharmace u tical factori es produ ce a range of p hysiologically act ive sub stances, so me of w hich w ill find th eir way into the effi ue nts, together with th e sol ve nts etc . in vo lved in c h e mi ca l processing. A r ece nt sur vey of Aust r alian manufacturers confirms that most rely on disposal by consignmen t to lice nsed hazardo us waste con tractors, and ma ny are ye t to imple m en t e nvironmental manage me nt systems which meet some of the more stringe nt req uire ments fo r dealing w ith these wastes. The cost of such facilities may impose significantly on the pharmaceutica l manufacturing industry. This paper describes the operation of a sp ecially designed multi-stage waste treatme nt plant in Swede n which meets the tightening regulati ons being imposed in Europe and U SA .

Pharmaceutical factories produ ce a range of physiologically active agents, ideally unde r patent to the manufacturer. T his m eans that each facility produces a unique mix of chemi ca l residues w hi ch va ries from plant to plant. Small am ou nts o f potent antibiotics, endocrine disrupti ve h ormones o r c h e mot he rap e u tic principles w hich are removed in batch wash and rinse procedures or otherw ise captu red physicall y need to be transformed into a h armless p rod uc t or chemically neu tered co nulli fy potential downstream ri sks , shou ld th ey esca pe into the outside e nvironment when m u ch remai ns unknown about their long-term impa cts (Wiesner, 1998) . In an effort to co mply w ith th e requirements of the American Clea11 vVaters A ct, the USEPA has recen tly m oved to impl ement n ew effl uent gu idelines and standards fo r the pharmaceutical manufacturing industry (EPA-

82 1-F-98-016). The new regu lations amend and clarify som e of the limitations imposed by the Act, based on best practicable control tech nology (BPCT) for pharm aceutical manufacturi ng faci lities and estab lish analytical m ethods fo r som e of their unique organ ic pollu tants. These regulations are expected to cost the industry nearly US $42 m illi o n annu ally. I n E u rope, many p h arm ace utical plants already pay carefu l atte ntion to strict stan dards for dealing with process wastes. They are dealing with these respo nsibilities by transport of so lid and semi-solid materials for high temperature incin eration, th e insta llation of in creasin gly sop histicated air emissio ns control technology and eve n the design and constru ction of spec ial wastewater treatment faciliti es o n-site. By the end of 2000, under directives from the European Uni o n , all comm ercial fac ili ties will need to implement plans to conform wi th the Urban

Untreated wastewater

~

Bioreactor (fungi)

= - = [5] = • = Flotation

Bioreactor (bacteria)

Activated carbon

Precipitation (flotation)

Bioreactor (m icroorganisms)

Pu rified wastewater

--t>

Sand filtration

Figure 1: Sequence of wastewater treatment at Astra Pharm aceuticals plant , Siidertalje , Sweden

Table 1: Process wastewater by Australian pharmaceutical industries (limited survey) Company name

Products

Process wastewater management

Source of data

Astra Pharmaceuticals, Sodertalje, Sweden

Naroprin , Xylocai ne, Citanest , Turbuhaler, Losee

Special wastewater faci lities for management of process effluent

Annual Report, 1997

Astra Pharmaceuticals, North Ryde, NSW

lmdur, Plendil , other patents under contract

Effluent management plan being developed by external consultants

Amrad Corporation, Melbourne

Products under licence from overseas entities

Meets guidelines for effluent organics and solvents consigned to licensed hazardous waste contractor for disposal

Annual Report, 1997 Annual Report, 1998

CS L Limited, Melbourne

Fl uVax, Pentavax, Bioplasma, diagnostic tests

Meets guideli nes for effl uent liquid wastes hand led off-site by licensed hazardous waste contractor

Annual Report, 1997 Annual Report, 1998

Fauldings Limited , Adelaide

Eryc (ant ibiotic) analgesics, injectables, long-acting pain killers

Solid wastes disposed off-site organics and solvents consigned to licensed hazardous waste contractor for disposal

Annual Report, 1998 Environmental officer, 1998

Peptech Limited, North Ryde, NSW

Ovuplant (deslorelin ), analogue of peptide gonadot rophin-releasing hormone, other research peptide products

Liq uid wastes hand led off-site Consignment to licensed hazardous waste contractor

32

WATER JANUARY / FEBRU ARY 2000

Environmental officer, 1998

Annual Report, 1997 Site manager, Sydney 1998


WASTEWATER

Wastewater Tr ea tm e nt Direc ti ve ap pl y in g to discha rges . However, a recent survey of pharmaceutical manufacturers in Australia has confirmed that the best known companies here rely heavil y on disposal of so lvents and other liquid process wastes by consign ment to licensed hazardous waste co ntractors (see Ta ble 1) . M a ny of these are yet to implem e nt environme ntal manageme nt system s to meet som e of the more stringent req uirem e nts for de alin g with th e wastes produced.

European Example Like man y similar manufactu rers in Europ e, Astra Pharmaceuticals has rece ntly recogn ised that its activiti es potentiall y ha ve a sig ni ficant impact on the e nviro nme nt. Th is is particularly the case in relation to discharge to commu nity-owned wastewater treatm ent plants and emissions to the air. D u ring the past three years, the company has comprehensively aud ited its facilities aro und th e world and is in the process of deve loping and imple me nting environmental management systems based O il 14001. T his includes the developm e nt of a re porting syste m fo r environm ental pe r formance indicators. More particularl y, Astra has developed a n ew approach to wastewater managem ent- the constructi o n and operation of its own specially designed wastewater treatm ent plan t at the company's centra l manufacturing and production unit at Sodertalj e, Sweden. Prior to the constructi on of th e new plant, productio n at Sodertalje was gove rned by efforts to maintain BOD leve ls within limits for acceptance into the trade waste eilluent strea m for the muni cipal sewage treatm e nt plant. Debate about n u trie nts in disc harge, eu trophication and ques tions about toxicity and poorly degradabl e sub-stan ces ca me to a h ead in the early l 990s. Th e compan y dec ided to look at alternatives.

rso

The Astra Plant-Sodertalje, Sweden The Astra plant at Sodcrtalj e is a large facili ty fo r dealin g with liquid pharmace uticals such as the local a nae sth e ti cs Xylocaine, C it an es t a nd Naropin. App roximately 90 per ce nt of the table ts and capsules manufactured by Astra, including po pular dru gs su ch as LoS ec (lipid-lowerin g agent), are produced at the complex. T he facili ty also manufactures Turbuhaler (fo r asthma) and wa reho uses pharmace utica ls fo r export. One of the requirem ents fo r dealing with wastewatei- at Sode rtalje was that the wate r be treated with biologica l processes. A co uple of wastewate r flows were ide ntifi ed as bein g particu larly tenacious and co ncentrated, but most simply were being poorly degraded by the standard processes . Most of the organic content in the wastewater was co mposed o f readily degradable solvents su ch as m etha nol, aceton e, ace taldehyde and ethanol. However, other compounds slowed down the processes and som e needed to be di verted to separate treatme nt. Problems were exace rbated by the fact that manufactu ring of pharmaceuticals is conducted in batches w hi ch crea tes major vari ations in wastewa ter constitue nts. Equalising the processes on a daily basis was not e nough to co mpensate fo r the variation.

Co11tin.ued over page WATER JANUARY/ FEBR UARY 2000

33


WASTEWATER

Design and Operation of the Plant W h en single-s tep processes were tested, mi croscopic analysis showed that there was a high concentration of fun gi among th e microorganisms. The fungi appeared to manage the variations in water quality much better than the usual bacteria. The result of furth er development was a process broken down into steps in w hich the pH in the first three steps was kept at 4 in ord er to give the fungi a favourable environm ent (see Figure l ). This was followed by two steps with neutral pH and bacteria. It was not possible to condu ct activated sludge processes with these di fferent sludge syste ms, so biofilm reac tors were used. With a retention time of 23 hours, approxim ately 90 per cent red uction is obtained of the usual organic compounds and a very large percentage of the poorly degradable compo unds. Toxicity , as tested using aquatic indicator species, is reduced to close to very low levels. Achi eving hi gher purification levels requires other processes. Th e first of these was treatment with activated carbon , where a dose of 50- 100 grams of carbon is n eeded per kL of water to redu ce th e rema inin g toxic ity and pharmaceutical r esid u es . Thi s is followed by phosphate p recipitation using iron and calcium , and then a further two-step biological p rocess. R edu ction of organic compounds was then greate r than 95 per cent and no toxicity could be measured and no pharmaceu tica ls were detected us111g spectrophotometer m ethods.

The Plant The plan t is built in a large process ball with acid-proof steel tanks, w ith each step or bioreactor being contain ed in a separate tank. This mak es it relatively easy to make futu re changes in the process by altering the number of steps, the organisms being used or the order of th e treatment processes. At present, th e by-product of the treatment process is a sludge consisting of more than 60% biomass and just un der 20% eac h of activated carbon and precipitated phosphates. The sludge is separated from the water in flotation tanks and sand filters, then dewatered and deposited in landfill.

Conclusion Many large companies and corporations are voluntarily produ cing environmen tal reports, and these numbers will

34

WATER JANUARY/ FEBRUARY 2000

increase as environmenta l responsibility becomes a mainstream issue for the Australian commu nity with the introduction of legislation requiring produ ction of annual reports o n environmental performance , as is required in American and European jurisdiction s. In add itio n, increasing numbers of sma ll shareholders are de m anding tha t th eir co mpany behave as a responsible citizen, e .g. by not breaching emissions requirem ents, by clea ning up pollution at a disu sed n1in e site etc. This poses a question for Australia: will a comparable tightening of regulations for dealing with wastewater from ph arm aceu tical pro cesses su ch as is occurring in the USA and Europe deal a fa tal blow to this growing new industry now estimated to have annu al revenues in excess of $4 billi on (BR W,

to enco ura ge im p le m e n tation of environmental management systems in similar large and m edium sized operations is likely to call for similar lateral thinki ng, not just by th e pharmaceutical industry but by others usin g substantial amounts of solvents in their operations

References Astra Phan11ace11ticals A111111al Report (1997), Astra Pharmaceutio ls, Swede n. J oyce J and Sorensen I-I ( I 999), Bioscrubbe r D esign, vVater, E11viro11111rnt & Tec/1110/ogy , 11/2: 37- 44. T he Top 1000 Companies, B11si11ess Review Weekly, November 16 edition , 1998. Wiesner D M ( 1998) H eal th R isks o f Medicinal R.esidues: More Questio ns Than Answers, Water, 25 (6) : 30-32 .

1998)?

Author

T his article has id en tified one of the ways that a pharmaceutical manufacturer can address th e issue of process wastewater in a responsible and environm entally acceptable manner which conforms with curren t expectatio ns fr o m th e community and the legislature . Moves

Dr Diane Wiesner spec ialises in human health and eco logica l risk assessment. She has pub lished two books on environmental impact and works as a consultant and auditor. Her ema il address is ecohea l@ozernail. com. au

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a

ENVIRONMENT

Abstract Adopti o n of clea ne r production and innovati ve design prin cipl es has led to th e c losing o f the wate r cycle w ithin a ve i·y large powd ered milk processin g fa c ility, rece ntl y c om mi ss io n e d b y Bonlac Foods Ltd. at Darnu111 , Vic toria. Wa stewate r from the plant is re used by in n ovative and fu ll y integrated recycling techno logy, vvith th e re ma inin g waste water used fo r irrigatio n o n co mpanyo wn ed farml and. C he micals used for clea ning the plant are recovered and re- used and th e w ater evaporated from the 111ilk is also recovered using advanced membran e technology . Wastewa ter trea tm ent lagoo ns and we tl ands pro vide habitat for aquati c birds, w hi le th e treed buffe r zones and comm erc ial woo d- lots provid e e nhanced regio nal w ildl ife corridors. E nergy co nservatio n measu res incorpo ra ted into the design o f the plant not o nly con tribute to low production costs bu t also reduce gree nhouse gas e missions to th e atmosph ere. Th is paper de tails innova tive design ele m en ts in the w ate r cycle with perform an ce and cost data , de mon strating the po te ntial for applicatio ns in othe r agroindustri es.

Introduction The w orld-wide agro- industry o f dairy processing has undergone, and continues to unde rgo, rapid change as a result of global co mpetition for marke ts. R ecogni tion of the n eed to maximise water efficiency and costs has foc ussed attention on Cleaner Production (C P) in the first instance and effo rts to close the water cycle through w astewater reclamation , recycl ing and reuse (R.RR) in the seco nd. In th e D arn um Park powdered milk plant, a $150 milli o n greenfi e ld develo pme nt , the Australian dai1y industry has established world best practice in both these areas.

Key CP and RRR Issues

Table 1: Typical Chemicals Used in Dairy Processing Type

Environmental Alkalis sustainability Acids It is now recognised that to remain competiSurfactants tive in world markets, Sequestrants th e da iry process ing Peptizing Agents industry must no t only Enzymes be economically sustainOxidisers able but also environ mentall y sustainable and responsible. Good business practice requ ires respo nsible appli catio n of C leaner Production (C P) and En viron111ental Managem ent Systems.

Comment

Generally sodium based Both inorganic & organic including nitric & phosphoric Anionic, nonionic, cationic, amphoterics

Protease, lipase, amylase Chlorine & peracetic acid

w ith th ese c hemicals are: • Im pact of sodium based c hemica ls on agric ultural land reuse system s. • Impact of nutri ents deri ved fro m nitric and phosphoric acids on rece iving wa ters. It is evide nt that recognition and attentio n to these issues at th e con ceptual sta ges o f produ ction processes is essentia l to achi eve clean er produ c tion.

Raw Material and Product Utilisation Although good business pra ctice aim s at 100% u tilisa tion , in prac tice , th ere will alwa ys be som e losses of raw material and produ ct. Selection, design , installation and op e ra tion o f processes whi c h Life Cycle Assessment As with the p rocess pl ant, capital maximise yield and minimi se losses is th e investme nt in reclamatio n , recyc ling and route to C P. An y raw mate rial o r product loss repre- re use systems needs to be based o n total sents bioso lids o f prote in, lipids, e tc w ith life cycle assessme n t. pote ntial for added value as fertiliser, stock Innovative Conceptual Design and fish food. Produ ction and recove1y Elements processes need to be se lec ted so that these Efficient man agement o f the water po te ntials are no t compromised, or w orse still , elimiRECUJMED WATEI FOR RE-IJSE IN FACTORY ---, n at ed , b y unwan te d or EVAPORATOR CONDENSATE EMERGENCY DtSCHAAQE und es i ra bl e c h e m ic a l TO RECEMNG WATERS contami nation. FAT RECOVERY ANOAEIJSE

CI.EAH WASTEWATER

Chemicals - Choice, Utilisation and Recovery R eclamation, recycle and reuse imposes strict crite ria on the c ho ice of chemica ls, not only for processes, but also fo r the clean- in-place (CI P) che mi cals. T ypical che mica ls used in th e dai1y processin g industry are shown in Tabl e 1. Th e princ ipal en vironm e n ta l issu es ass o c iate d

HIGH SOUDS, HKlH

a LOW pH

AGRtCULTIJRAl RE-usE BY SPRAY IRRtGATION FOA HAY / Stl.AGE

FACULTATIVE BK>lOGICAL REACTOR

WUITTAANOWET

WEATHER STORAGE

Figure 1: Simplified Typical Water Cycle Flowsheet. WATER JANUARY /FEB RUARY 2000

35


ENVIRONMENT Costs

Table 2: Input/Output Performance Data - Facultative Biological Reactor

pH BODs Suspended Solids Total Nitrogen as N Total Phosphorus as P Electrical Conductivity Total Dissolved Salts Sodium Adsorption Ratio

Table 3: Cost Data - Wastewater Systems System

Capital Cost ($A)

Primary Secondary Tertiary (R RR)

1 ,000,000 2,250,000 3,750,000

TOTAL

7,000,000

36

WATER JANUARY/ FEBRUARY 2000

8-9

8-12 2,000 750 75

pH units mg/ L mg/L mg/L mg/L µS/cm@25'C mg/ L

cycle is a key elem ent in implem entation of cleaner production in most agro-industries and the dairy industry is no exception. The modern dairy processing plant not only uses sign ifica nt quantities of high grade (potable) water, but where evaporation is used, as in milk powder plants, the plant will also be a water producer. In such cases, depending on the overall water balance, an essentially closed loop water cycle can be achieved. Wastewater streams can be categorised on the basis of quality as well as quanti ty, so that different stream s may be segregated into different recovery processes, leadin g in so me cases to valu e-added by-products. A typical flowsheet for closing the water cycle is given in Figure 1. In the case of the Darn um Park plant, whjch at fu ll production can produce over 300 tonnes of milk powder per day, from approximately 3 ML/d of raw milk, the spray dryer condensate represents up to approxjmately 2.5 ML/d . Although it is a condensate, it still contains mjnor amoun ts of salts and biosolids due to cany-ovcr. A reverse osmosis unit was installed to upgrade its quality so that it can be recycled to the fact01y in place of town water. The concentrated used C IP stream s, conta ining sod iu m, ni t rogen and phosphorus as well as stripped biosolids are then passed through nanofiltration units for recovery of the acid and alkali cleaning chemicals. The fats and oi ls are recovered in an Induced Air Flotation (!AF) un it for reuse as tallow. T h e st ream wit h hi g h so lid s is processed directly to produce stockfeed. The comb ined t ota l wastewater stream is then oxidised in a fac ul tative biological reactor, with a mean th roughput of 1 ML/d (1.5 ML/d maximum) w hich reduces BOD and SS, as shown in

Primary trea tment (solids and fa t recovery), seco ndary biological treatmen t and tertia ry reclamation, recycl ing and reu se systems totalled $7 milli on , as summarised in Table 3. T his co mpares w ith a total capita l cost for the w ho le plant of some $150 million.

Mean Concentration Input Output

Unit

Parameter

40 80 75 30 1,200 900

1 ,200 900

Conclusions

<9

Table 2. An innovative diffused aeration system not previously used in Australia, achieves high efficiency oxygen transfer in the facu ltati ve reactor. All wastewater, together with any con taminated stormwater, is collected in a winter and wet-weather storage lagoon, fro m wh ich it is utilised for both irrigated pasture and agro forestry. 170 hectares are developed to hay/ silage production and 35 hectares for bounda1y trees and com mercial wood-lot production. In addition co the factory waste, all wet wea ther run -off from the site is co!Jected in a stormwa ter retention pond with online q uali ty monitoring and co ntrol and then discharged to the receivin g water through constructed wetlands.

Adopti on of cleaner production and inn ovative conceptual process design principl es has led to closing of the water cycle within th e agro-ind ustry of dairy processing at a S 150 mi lli on green field site in Victoria, Austra lia. World best practice has been ac hieved in maximising wastewater reclama ti on, recycling and re use, and th e principl es have clea r potential for application in o ther agroindustries.

Authors John Parker is M anaging Director an d Stuart Longmuir is D irecto r of Engin eering at WSL Consultan ts Pty Ltd, enviro nm ental designers of th e system . Wayne Stoll is G roup Manager, Environm ent, at Bonlac Foods Limited. Email: wslcon@ozernai l. co m.au

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II

ENVIRONMENT

The electrostatic precipitator removes dust from cement kilns' exhaust gas

Abstract Th e recyc lin g o f indu strial b yproducts can o fte n be ve ry diffi cult and frau ght with o bstacl es. H oweve r it has been shown that if a scie ntific and system ati c approach is taken th en it is possible to fu lfill th e legal du e dili gen ce pro cess and produ ce a saleable product. O n e such exampl e is cem ent ki ln d ust (C KD) , an alkalin e by-produ ct fro m th e ce m ent m anufacturin g process. D ue to th e che mi cal and ph ysical nature of th e kiln dust, ie pre dominate ly fi ne ly ground lim estone , it has pote ntial as a low cost sou rec of li m e for th e agri cultural and ro a d constru ction industri es. In rece nt ti rn es, t he impac t o f ac id sul fa te so ils on su rface water and groundwa te r quality has resulted in th e use of lime p rodu cts in in creasin g qu antities fo r re m e diation purposes. Qu ee nsland C e m e nt Ltd co mm ission ed an exte nsive stud y of C KD , som e times kn own as Lean Lim e. This pa p er repo rts th e c hemical an alyses and di s cusses the eco logical and o th e r e ffec ts o f cem ent kiln dust o n w ate r quality and soil chem istry wh e n used as an am e liorant in acid sul fa te so ils. D etail ed testin g and compariso n wi th ag-lime (c ru shed screened lim estone), has shown that CKD is a suitable m ate rial fo r th e managem ent o f acid sulfate soils.

Introduction In th e cem e nt indu stry a ran ge o f differe nt materials pro vides th e essential

lime , silica, alumina and iro n necessary fo r the productio n of ce m ent. In ge ne ral th e raw m aterials are from natu ral earth deposits. Th e primary raw mate rials at Qu eensland C em ent Ltd (Q C L) Darra plant incl uded lim esto ne (dead coral), clay, sa nd and iro nstone . Th ese raw m aterials ca n contai n naturall y occ urring trace e le m e nts such as antim o ny, arseni c, barium , be ryllium , cadmium , chromium , lead , m e rcury, ni c ke l, se len ium , stron tium , silv e r, thallium , van adium , zinc, bro mine , ch lo rine, fl uorine , and iodin e. T he a mount o f t h ese co mp o n e nts depe nds o n th e geologica l fo rmations fro m w hic h th e raw mate rials are m ined. Gi ven th e che mi cal nature of C KD it is a po te ntial amelioranc o f ac id sulfate soils. To eva luate its pote ntial, Griffith Un iversity was co mmiss io ned to unde rta ke a controlled study using CKD and ag-lime unde r labo rato ry co nditi o ns, and

to assess its safety, R.M T Inc in USA w as commission ed to undertake a risk assessm ent .

Chemical Characteristics of CKD To be able to use C KD as an am e liorant its che mi ca l c haracte ristics must be kn o wn and eva luated . As part of th e ev a lu a tion CKD was sampled and analysed for major and m inor c he mical constitu e nts. T he sa mples w e re coll ected at different heig hts from the stoc kpile . Th e m ajor c h e mi ca l r es ults are presented in T able 1. T he data sho w that the material is predo minantly calcite and arago nite (lim esto ne) w ith e levated leve ls of halite (N aCl) and anhydrite (CaSQ4). Th e re arc also approx imate ly equ al amoun ts of ce,n enti o us compounds and quartz . T he samples we re also analysed fo r the foll o wing organics; polycycl ic aromatic

Table 1: Major Chemical Analysis (% w/w) (moisture free basis) Stockpile

Cao

Si02

A'203

Fe20 3

MgO

503

Na20

K20

SrO

35 .13 39.3 31 .3

16.6 19.1 13.9

5.01 6.31 4.09

2.2 2.48 1.87

1.12 1.36 0.99

4.28 5.29 3.52

3.09 4.94 1.58

1 .81 2.7 0.79

0.487 0.54 0.44

35.79 40.98 29.8

20.1 26.83 15.92

6.41 8.58 4.68

2.37 3 1.62

1.28 1.56 0.93

3.04 4.8 1.17

1.81 5.08 0.29

1.40 2.52 0.31

0.43 0.5 0.37

Fresh CKD

Average Maximum Minimum Aged CKD

Average Maximum Minimum

Fresh CKD means material less than 12 months in age. Aged CKD has undergone weathering resulting in some hydration of free lime and cementitious components.

WATER JANUARY / FEBRUARY 2000

37


ENVIRONMENT

Table 2 : Met als Analysis, mg/kg (as received basis) Location

Cu

Pb

Zn

As

Cd

Cr (total)

Ni

Mn

Sb

Sn

Hg

CKD North Composite CKD East Composite CKD Fresh Composite CKD Fresh Average Environme ntal lnvestigation1 Health lnvestigation 1 Backgrou nd1 ATSDR Soil Screening Levels 2

49 34 33 35 36

105 65 48 53 69

100 82 39 32 63.1

17

6 11 11 9.3

1.1 0.5 4 0.5 0.65

45 30 48 47 42.1

19 10 11 11 13

259 199 145 162 191.6

18.3 0.6 0.5 0.6 3.5

1.8 1.6 0.8 0.9 1.28

0 .05 < 0.05 0.06 < 0.05 0.06

300

200

20

3

50

60

500

20

50

1

4-12,600 5000

4-44 20

1-25

0.001-0.1 15

31

47,000

NHMRC guidel ine3 Residential RBC for CKD (mg/kg) 4

60

300 <2-200 2-180 400 15000 1000

300

3,100

100 20 0.2-30 0 .04-2 20 40

7000

100

20

23,000

0.43

39

0.5-110 2-400 300 (Cr6+) 1000 50000 (Cr3+) 100 (asCr6+) 600 390

1,600

1500 1,800

1 . Queensland Department of Environment Contaminated Land Guidelines 1992 2 Critical Evaluation of the Potential Impact of Emissions from Midlothian Industries: A summary Report Office of Air Quality/ Toxicology and Risk Assessment Section, Texas Natural Resource Conservation Commission (USA). 1995 3 Health-Based Soil Investigation Levels, National Environmental Health Forum Monographs Soil Series by P lmray and A Langley, No.1, 1996 4 Risk based concentration for Queensland Cement Ltd's Cement Kiln Dust Stockpiles , by RMT Inc., Revised January 1998

hydrocarbons (PAH), polych lori nated biph eno ls (P CB), benzene, to lu e ne and xyle n es (BTE X ). T hese comp o und s were all below the detecti o n limits. A vari ety of metals and non- m etals were measured in th e CKD and th e results are prese n te d in Tabl e 2, compared w ith th e levels fo r further in ve sti g ati o n r eco mmend e d by Qu ee nsland and Australian autho riti es. R esults for all samples take n fall b elow th e Qu ee nsland's EPA co ntami nated land e n viro nmental guide lin e (1992) values except for a sin gle sampl e whe re chro mium registe red 53 mg/ kg versus an in vesti gati o n guid e li ne va lu e o f 50 m g/ kg. T he average va lu e fo r c h romium is 42 .17 mg/ kg (see T abl e 2). The levels o f m etals in th e sa mples o f CKD (fresh or aged) in vestigated are be low th e acce pted national and international environmental investigati on and health based levels. Tabl e 2 also reports soil screen ing levels reco mme nde d by the US Agency fo r T ox ic Sub stan ces a nd Di seas e .R egistry (AT SDR.) for protection o f hum an exposure throu gh th e inges tio n o f soil particles. E xposure to soil co ntain ing co n centratio ns be low th ese SS L valu es is not expec ted to result in adve rse hea lth effects. So il con centra tio ns in excess of these scree nin g leve ls onl y suggest th e need for furth er evalu atio n o f th e potentia l for hum an exposure, and are not necessarily indi cati ve o f a health con cern .

CKD as an Ameliorant for Acid Sulfate Soils A cid sulfate so ils (ASS) are form ed by the exposure of pyrite in the soil to air fro m agricultural o r developme nt ac ti vities. If th e soil is w aterlogged, ie th e 38

WATER JANUARY /FEBRUARY 2000

pyrite is below the water tabl e, then oxidation of the iro n (II) with th e liberatio n o f acid , does no t occur. Given th e characteristics of CKD and its high lime co ntent it could be ideall y suited as a soil ame liorant for th e trea tme nt of acid sulfate so ils. Fres h hot CKD is ge nerally I 00% passing 200 micro metres and wea th ered CKD is screened to suit the clie nt 's require me nts. To evaluate the effecti ve ness o f C KD a trial was carried out by S[{fig11a et . al. ( 199 8) a t th e Griffith Uni ve rsit y, Brisbane under laboratory conditio ns, co mparing it with ag-lime . Th e so il sampl es we re air drie d , ground to less than 2mm and tested fo r oxidizabl e sulfu r. Th e liming amendm ents were added at a rate o f 1.5 tim es th e th eoreti cally calculated quantity o f CaCO3 required to neutralize th e ac idity produced if all the sulfides w e re oxidi zed. After in c ubati o n for th e qu o ted pe riods , a 5 g sampl e w as ex tracted on a 1 :5 soil: w ater ratio, filt ere d and tested fo r pH and sulfate.

Figure 1 show s the effect of ag- lime and C KD (also kno wn as Lean Lime) in contro lling pH in the trials. It ca n be see n that C KD and ag-lime are both effective in controlling pH under varying temp erature conditions w ith tim e. While initial results indi cate that th e C KD is more benefi cial than ag- li m e furth e r tests are co ntinuing co validate this trend D ann et.al. (1989) at C S!RO also e valuated ag- li111e, CKD and sewage ash as am eli o rants for ASS unde r fi eld and glass hou se condition s concluding that th ey were all effec ti ve in am elio ratin g adverse so il fac to rs.

Surface Water T o assess the impact of C K.D- amended ASS o n surface water and groundwater due co the presence o f m etals or nonmetals Si[fig11a et al. prepared th e filtrate samples, used to measure pH, for analysis. Table 3 presents the fi ltrate data fro m the S[[fig11a ct. al. trials w hich compared the leaching from ag-lime and CKD in the treatm ent of ASS .

pH in Soil as a Function of Time and Temperature

8,---- - -- - - - -- -- - -- - ----,

---

Control (4 wks) Ag-lime (4 wks)

-+-

Lean Lime (4 wks)

...........

Control (6 mths)

4

3 2

â&#x20AC;˘

20C

â&#x20AC;˘

i

Ag-li me (6 mths)

30C

40C

Lean Lime (6 mths)

Temperature (C)

-+-

__._

Figure 1: Effect of Temperature and Time on Filtrate Water, Siffigna et al (1998)


ENVIRONMENT

Table 3: comparison of Acid Sulfate Soil Filtrate and Surface Water Quality Data to Risk-Based Concent rations, March

1997

Constituent

Control Lean Lime Ag-lime Mud Island Filtrate Filtrate Queensland 4 Filtrate Concentration Concentration Concentration (mg/ L) (mg/ L) (mg/ L) (mg/ L)

Aluminum 226 Iodine < 0.1 149 Iron 0.0055 Lead Potassium 1 Sodium 1095 Strontium 0 .367 4 .16 Zinc pH (standard units) 2.29

0.25 0 .3 0.13 0.002 167 1467 12 0.018 6.21

Australian Protection of Aquatic Ecosystems (freshwater) (mg/ L)

ECOTOX1 Threshold for Surface Water (freshwater) (mg/ L)

(mg/ L)

< 0.1 if pH >6.53

0.58

3

< 0.1

0.5 0.0013 47 1116 0.928 0.034 6.20

AQUIRE 2

1.0 0.001 to 0.005

1.0 0.0025 50 to 400 1,020 1.0

8.20- 8.80 0.005 to 0.05 6.5 to 9.0

0.1

NOTES:

1 2 3 4

USEPA, 1996. EcoTox Thresholds Database. USEPA, 1996, AQUIRE, The Australian standard for aluminum is based on pH. Water samples collected from Mud Island, Queensland, Australia.

Table 3 shows nine constitu ents in the fi ltrate compared to risk- based concentratio ns in surface water. In the fi ltrate from the Lea n Li m e tre ated so il, bromine, sod ium , strontium and zinc were above the ECOTOX or AQU I. RE gu idcline va lu es. Strontium , w hic h is foun d natu rally as strontium su lfate or Celestite, was the hi g h est c leme nt exceedin g the AQU IRE guide lin e val ue by a factor of approx imately 12. The ot h er compou nds, though above the AQU IRE guideline valu es, were similar to o r less than the control and/ or ag- lim e treated soil. The leach ing of stron tium was further assessed by carryin g ou t the USEPA Toxic i ty Cha ra c t eris ti c Leach i n g Pro cedure (T CLP). The results for stronti u m were 33.6 and 38.6 mg/ L. In assessing th e leac hi n g c h ara c t e ri stics of u ndiluted CKD the TCL P test needs to be interpreted carefully becau se of the hig hly ac id e n vironment under which the test is carried out and the fact that it does not necessarily re fl ect ame nded acid sulfate soils. The testi ng has shown that stron tium is a highly mobil e ion and as such could be present in w ate r at levels near or above background pa rtic ularly if the so urce is around natura ll y occurrin g Celestite or limestone deposi ts. For exa mpl e, the naturally occ urrin g level of stron tium at Mud Islan d, Queensland, was measured at 8 .2 and 8 .8mg/L, w hile in the USA strontium has been reported in drinking w ater as high as 34.5 mg/ L (USEPA 1988). Give n the resu lts it was co ncluded that th e impact of C K D on water w hen used as an ame liorant is no wo rse than background w he n the amended so il is exp osed to an acid e n vironment.

Groundwater Groundwater ca n be i mpacted by percolation of su rfa ce wate r through a contam inant sou rce. This process creates leachate that can continue in a vertical movement to deepe r groundwater reservo irs o r ca n move laterall y as a subsurface f:'low depending o n the geologica l fo rmation of the underlying strata. T he TCL P test has beco me a standard measure of the potential of a waste to pollute soil an d ground wate r. TCL P testi ng o n C KD gra b sa m ples show that the material genera ll y has a hi gh buffering capa city (T CLP extract pH = 2.8). The leach ing resu lts all fall below the USEPA R C RA guide li nes for ha zardous materials and the Brisbane C ity Cou nc il gu idelines for leac hate from unlin ed landfi lls (except for molybdenum where the detection limi t is greater than the BCC Guideline limit). The TCLP resu lts suggest that heavy metals and non- m etal s will have little or no impact upo n gro undwater, eve n 111 hi ghly ac idic en vironments .

Direct Contact Exposure As C KD is a by-prod uct it is prude nt to evaluate human exposure to dire ct contact. RMT Inc., M adi so n , USA (1998) undertook a risk evaluation of CKD to assess ecolo gical or hum an hea lth impacts. The risk-based calculations we re carried out in accordance with ASTM Ri sk Base d Co rrec tive Actio n Stan dards a n d USE PA Ri sk Assessment Guidance procedures. T he sa mples of C KD tested were a blen d of fresh and aged material th rougho ut the w hol e stockpil e, a worst case sce nario. Th e fi ndin gs of the risk eva luation summari sed as upper- bound C KD co nstitu en t concentrations and res iden-

tial risk based co ncentrati ons (R.BCs) are presented in Table 5. The following assumpti ons were used in the risk evaluatio n:

Residential Exposure â&#x20AC;˘ R esidential RB Cs for noncarcinoge ns are based on childhood exposure . That is, the ingestion of200 mg of so il per day for 350 days per yea r for an exposure period of 6 years. â&#x20AC;˘ Residenti al RBCs fo r carc inogens are based o n co mbin ed ch ildh ood and adult exposure over a 30-year exposure period with an adult ingesti on rate of 1200 mg per day. Table 5 also lists som e Austral ian recommendations, derived by Imray and Langley ( 1 996) for the National Environmental H ealth Forum. T he results show that the risks associated w ith direct contact exposu re to C K D are low, because (excep t for arsen ic) constituent co ncentra tions did not exceed RBC 's . Th e upper-bound arse nic conce ntrati on in the C KD (17 mg/ kg) is the only pa rameter to exceed the RB C of 0.43 mg/ kg. Measured arsen ic co ncentrations (6-11) are at the lo we r end of the range common to Un ited States natural so ils (1 mg/ kg to 50 mg/ kg; USEPA , 1983) and Australian background levels 0 .3 to 30mg/kg (Quee nsland 's EPA Contaminated Land Guidelines 1992). Given these va lues for arsenic in C KD , human health effects were conside red to be no greater than those already existin g from ba ckground so urces.

Conclusions The work ca rried out by Dann et. al. (1989) and Siffigna et . al. (1998) has shown th at CKD ca n su ccess fully am eliorate ASS . Further assessments WATER JANUARY / FEBRU ARY 2000

39


ENVIRONMENT

Table 5: Comparison of Concentrations Reported in CKD To Risk-Based Concent rations Constituent Concentration In CKD * of Concern (mg/ kg)

Aluminum Antimony Arsenic Barium Cadm iu m Calcium Chloride Chromium 14 > Cobalt Copper Iodine Iron Leadx!5l Magnesium Manganese Molybdenum Nickel Phosphorus Potass ium Sodium Stronti um Tin Zinc

35 ,513 18 .3 17 257 1.1 2 9 7,887 14,900 48 12.1 49 <10 18,9 55 105 8 ,201 2 78 1. 7 19 48 0 1 4,528 15,653 4,410 1.8 100

Residential RBC (mg/ kg)

Australian Soil Guidellnes<1 > (mg/ kg)

78 ,000 12> 31 12> ~ (2) 5,500(2) 39 890 ,000(3) 840 ,000 131 39012> 4,700(2) 3,100(2) 54_75(3) 23,000(2) 390,0 0013> 1 ,800 12> 390(2) 1,60012) 890,ooo<3) 2 .2 X 1 06(3) 550,0 0013) 47,000 12) 4 7,0 00(2) 23,00012>

100 20

100 1,000

300 1,500 600

7,000

â&#x20AC;˘ Maximum concentration in samples from the top 0.5 m of the CKD stockpiles. (1) lmray, P., and A. Langley. 1996. (2) USEPA Region Ill, Office of RCRA, 1996 . (3) Estimated based on recommended diet ary allowances. (4 ) RBCs are for Cro, CKD dat a is total Cr. (5) No RBCs for Pb , it is a developmental toxicant.The screening level for USEPA is 400 mg/kg.

40

WATER JAN UARY/ FEB RUARY 2000

Evnl11ntio11 of Q11ee11sln11d Ce111e11t Ltd Ce111e11f Kil11 0 11st Stockpiles, Brisbane, Q11ee11Sln11d A 11stmlin, January R evision Texas Natura l R esourc e Cons e rvation Co111111ission (USA), (1995) Critical Evnl11ntio11

of the Potwtinl l111pnct of E111issio11s fro111 Midlothia11 /11d11stries: A s1111111rnry Reporr Q[f,ce of A ir Q11nlity! ToxicoloR)' and R isk Assess111e11t Section USEPA (1996) AQU IRE, Aquatic Toxicity l nfor111at ion R etrieval, Office of Research and Devdop111ent, National H ealth and Environmental Effects Research Laboratory, Mid-Continent Ecology D ivision U SE P A(J988) Drinking Wate r Criteria Document fo r Stable Stron ti u111, E nvironm e ntal Criteria and Assessment, C incinnati, OH 45268

The Author

NOTES:

ca rri ed out by RMT Inc. USA and Palmer T ec hn olo gies has shown that C KD w he n ma n aged correc tl y has m inimal effect o n the environmen t and an acceptabl e risk on human health . Analysis of CKD and dead lim esto ne coral from M oreton Bay shows littl e difference between the chem ical species and TC LP tests carried out have show n that the leac hate resul ts are belo w landfill guidelin e valu es, for wa nt o f a be tte r co mparison . Stro n tiu m (a natu ral ly occ urrin g min eral) is the m ost sol uble of the m etals in limestone evaluated and in the fil trate fro m the laboratory trials carried out by Si ffign a et n/ i t exceede d the U SEPA AQU[R.E gui deline va lue . H owever, ba ckground levels IN gro undwater are sim ila r. A li terature searc h fou nd the level of stro ntiu m in many drinking w ate rs in the USA rs h igher than the AQ U IR E guideli ne valu e. T he research and testing carried out to date has shown that C KD is as effective as ag- lime i n ameliorating ac id su lfa te so ils. O ne of the be nefits in this case is the economi cal ad va ntage that C KD has over lim estone t is a lower cost product becau se it has already been min ed and fine ly gro u nd.

Queens land Depart111ent of Environ111 e nt ( 1992) Conta111inated Land Guidelines R MT Inc. Madison W I U SA. (1998) Risk

T h is w o rk h as sh ow n th at byp roducts w hen correctly i nvestigate d and man aged ca n e successfull y used . Further testin g is continu in g through t h e De pa rtm ent of Na tural Resources, Q u eens la nd , on t he leac h ab il ity of particular e lements in vario us acid sulfate soils under sim ulated weath er cond itions.

References Allingham D .P . and Neil D.T., ( 1995) The

supmtidnl deposits n11d ~[Jeers of com/ dredgi,1,~ 011 M 11d Isln11d, Mo reto11 Bay, southeast Q 11ee11sln11d Zeitsc h rift fur G eomo rpho logie, 39 , Septe m ber 1995 Dann P. R.., Barr B.S. and. Cunningham R.. B (1989) Co111pnriso11 of Se,11ale Ash, Cr11shed

Li111esto11e n11d Ce111e11t Ki/11 Dust as A 111elior1111ts for A cid Soils. Australian J ournal of Experimental Agricultu re, 29 , pp 24 1-9 lrnray P and Langky A (1996) Health-based soil investigation levds, National Environmental Health Monographs, Soil Series N o . I Puglisi A.L., Hokck W.A., G runwald D.J. and. R usso 111 C. L ( 1996) Eco'/i,x: A Database <?f

Toxic Effects to Aquatic a11d Terrestrial Species. USEPA , 1996 Siffigna P . G ., M ath e rs N .J., H ey K.M., Mc Leod J. D. and . M ercep P.J. (1998),

Oxidntio11 nud Ne11tmlisnrim1 of Pote11tinl Acid S11lfnre Soils .fi-0111 the S1111shi11e Const, Q 11ee11sln11d, International Soils C o nference Proceedings, Brisbane, April 1998.

Dr. Greg Palmer has over 13 years expe ri ence in the ce ment industry at Ade laide Brighto n Cemen t, Sunstate Ceme nt Ltd , and Q uee nsland Cem e nt Ltd , afte r train ing in D e nmark and Sw itzerlan d. H e has wo rked closely w ith cem ent co mpan ies w ith in Australi a and overseas. His com pa ny provides process engineering services to the cement and mi nerals industries .

water Contributions Wanted T he W ater j o urnal w elcomes the submission of papers e qu ivalent to 3 ,000- 5 ,000 wo rds (allow ing fo r graphics) relati ng to all areas of the wa te r cycle to be publishe d in the W ater , W astewate r, Environ m ent and B usi n ess sections of the journal. Y ou m ay email a draft cop y w ith fi gures and graphi cs to Fea tu res Ed i to r , B o b Swin ton , at e m a il swi ntonb@c031 .aone .net. au F o ll ow i n g h is assessme nt o f suitability, hard copies w it h figures an d g rap h ics sho u ld b e m ailed to 4 Pleasant View C rescent, Wheele rs H ill, V ic 31 50 . T opical stories of up to 2,000 words may also be accepted.

Graphics C olour o r black & w hite photographs and illustrations can be sen t eith e r as transparencies o r p rin ts, or as high res scans (300dpi) as tiff or eps files on a 100 MB Z ip disk.


m

BUSINESS

HACCP APPLICATION TO BRISBANE WATER R Gray and M Morain Introduction Early in 1999, Brisban e W ate r (BW) 1nanageme nt de termined chat BW would im pl eme nt a H aza rd Analysis and C ritica l Cont ro l Points (HA CC P ) - base d process control system for its water trea cn, e nc, sto rage and distribution acti vities. As a sta rting point, on e of the au thors (R . Gray) attended NATA's H ACCP T rainin g Course in orde r to obtain a m o re in -de pth knowledge of th e pro cesses in vo lved in imp le m e ntin g H ACCP in a large organisation. Furth er on in the process, the Centre for Food T echnology (CFT ), a busin ess unit of the Q u ee ns lan d De partm e n t of Primary I nduscries, was engaged to assist with the de v elop ment and imple me ntation of th e H A CC P plan. C FT's T eam Leader fo r th e proj ect was Marc M o ra in , who is coau thor of this article .

Why? E very fi eld of operatio ns, from the m ost sophisticated to th e most m u ndane, ha s its pitfalls and the Water Industry is no exception. Problem s such as burst m ains, taste complaints, corrosion and algal toxins are but a few examples of everyday happenings in this industry. In the c urr e nt climate o f co n sum e r ad vocacy and litigatio n , it is becomin g inc reasingly impo rtant to elimin ate or co ntrol eve nts such as these to the bes t of o ur ab ility. T here are va rious risk assessment tools available for this purpose H A C CP is but one of them.

What Is It? HA CC P (H aza rd Anal ys is and C ritical Control Points) was originally de v eloped in order to address microbiologica l hea lth hazards in food. The Pillsbury Co mpany, U.S. M ilitary and NASA wo rked together in the late 1950's to mid 1960's to develop a process to elimin ate the risk of food poisonin g of astronauts. Subsequently, the process became accepted in the foo d in du stry in th e US in the 1970's and in A u stralia in th e 1980's. It passed into Au strali an Food legislation in the 1990's.

HACCP for Water There is an increasing trend to classify wa te r as a food, maki ng th e application

of H ACCP pri nciples to its produ ction, sto rage and distri bution a logical step. Brisbane W ater operates four water treatme nt plants: Mt Crosby Eastbank and Westbank, draw ing wate r from the Brisban e River; North P in e, drawing water directly fro m North Pin e Dam ; and Enoggera, w hich is an inte rmitte ntl y- used facility in Brisban e's W estern suburbs.

Definition Th e Codex Alime ntari us definition of H ACCP ide ntifi es H ACCP as a tool for the syste matic analysis of a process to iden tify potential haza rds and plan fo r th e control of those haza rds. It is a tool for the develop me nt of process co ntrol syste ms 111itlii11 a q11ality 111anage,ne111 systeJ11 . It is not: • QA or TQM - it is an ele me nt of th ese • The on ly risk based hazard ide ntification tool • A tool fo r ve ri fying plan t design • A me thod o f doc um e ntin g what you already do • A tool that ca n id e nti fy ha za rds witho ut an experie nced tea m

The HACCP Team Because BW 's responsibili ties extend from th e raw water inlet of the treatme nt plant to the consume r's tap , a wide range of processes is in volved in the provision of water supply. T he H ACCP tea m assemb led reflects the diversity of operations involved: • Treatm e n t Plant M anagemen t • P lant ope rato rs and supervisors • Wate r Systems (distribution & maintenance) personn el • Risk Managem ent E ngin eer • Scientific Pe rso nnel • Quality Syste ms and C ustomer Lia ison pe rso nnel • HA CCP Consultan ts (C FT)

Developing the BW HACCP Plans Th e scope chosen for the H ACCP plans refle cted B W's area of responsibility from raw water intake throu gh to the co nsumers tap and assessed both safety and quality risks. As this scope span ned across four water treatme nt plants an d the distributio n system it was decided to draw a separate H ACCP p lan fo r each treatment plant and the di strib u tion syste m . Product desc riptions (o r specifications) we re develo ped from N ational H ealth and M edica l R esearch (N H and MRC) gu idelines and customer requirem ents by the H ACC P tea m. Even more rigid sp ecifi ca tions were set for treated water from the trea tment plants to ensure that distributed and re ticulated wate r would conform to spec ifi cation. " In line" specifica tion s were also deve loped for raw materials and steps w ithin th e process. Fl ow charts were developed, using the fo llowing symbols, and verified by th e H ACCP team to desc ribe the steps in each process assessed. This resulted in a separate flow c hart for eac h trea tme nt plan t and the distribution system. Symbo l

0 Q

\7 D

Descrip tion Ope ration Tran spo rt Storage Insp ection

Each step in th e process was ana lysed by the HACCP team to ide ntify potenti al hazards at that particular step and w hat effect they wo uld have on the sa fet y or quali ty of the treated water. A risk assessment was con du cted on eac h h azard us in g th e d escr iptors summarised in Tabl e I , and the simple fo rmula:

Table 1: Risk Descriptors Likelihood

1 2 3 4 5

= Improbable event: Once every five years = Remote possibility: Once per year = Occasional event: Once per month = Probable even: Once per week = Frequent event: Once per day

Severit y

1 2 3 4 5

= Negligible: no impact or not detectable = Marginal: significant impact = Significant: impact on t arget levels = Major: impact on franchise levels = Critical: public health risk

WATER JAN UARY / FEBRUARY 2000

41


BUSINESS

Likelihood x Severity= Total Assessed R isk

Ali Total Assessed Risks with a sco re equal to or greater than six were considered signifi cant. Potential H azards with a Total Assessed Risk less than six were considered insignificant. The cause and effect of eac h hazard was assessed by the HAC CP team and preventive measures that addressed the ca use of each hazard were identified. Literature evidence or historic data was used to validate each of the identi fied preventive measures. In most cases preventi ve m easures had prev io usly been estab lished and implemented, the H ACCP process provided a fu rther verifica tion that these measures were effective. Steps in th e process wh ich had potential hazards of significant risk that co uld be controlled were described as C ri tical Control Points (CCP) if they posed a public health or safety risk or Q uality C ontrol Po ints (QCP) if they posed a quality ri sk. The HACCP team se t Target and Criti cal Li mits for t he preven ti ve measures. Historic data and expe rience were used to vali date Target Limi ts. NH and MRC gui delines and resea rch find ings were used to validate Critical Limits. Proce du res we re es tab lished to monitor each CCP and QCP aga inst critical limits. T hey indicated: • W ho is responsible for monitoring. • W hen and how often they monitor. • W hat method is used to monitor. • W here res ul ts of m o nitoring are recorded. In most cases these procedures were cross-referen ced to procedu res previo usly implemen ted by BW's ISO 9000 series Q uality Assurance system. Correcti ve actions to be implemented w hen cri tical limits within the process are exceeded were established by the HACCP team. T hese actions included, where appropriate, instructions add ressing: • W ho is responsible fo r takin g th e actions. • Stopping the process and isolatin g the trea ted water in severe cases • R e-establishing process control and preventing future occurrences. • D etermining th e cause of th e loss of control. • What records are to be made of the occurrence. In m ost cases these Corrective Actions were cross-referenced to procedu res previously implemented by BW's ISO 9000 series Quality Assu ra nce 42

WATER JANUARY/ FEBRUARY 2000

system or implemented Con tin gency Plans. A Verificatio n Schedu l e was designed by the HACCP team to assure the H ACCP plans were effectively controlling the process. This schedule included review of q uality repo rts, custo m er complaints, internal and H ACCP system aud its as we ll as HACCP reviews.

Recommendations One of the requirements of im plementing a H ACCP Plan is that there are changes to be made to process in orde r to address risks in volved. T hese changes range from vital to incidental. Some of the most important o nes were: • R aw materi als control: - especiall y raw water and catchm ent issues - treatment chemicals such as alum, lime, sodium hypochlorite. • Beca use of th e geograph ical positio n of th e Mt Cros by p lants (o n the Brisbane River), th e use of on-line biological indi cators should be considered. • Contingency plans for various scenarios such as blue-green algae blooms, Cryptosporidium!Ciardia, tru nk mains bu rsts etc. to be revised and updated. • Issue of illegal conn ection to new mai ns to be investiga ted . • Review new mains co nstru ction and commissioning procedures with respect to H ACC P requirements.

Conclusion The imple mentation of the developed HACCP plans provides Brisbane Water with a 'fa bric' to tie together the disparate elements involved in providing a potable water suppl y from raw water intake to tap. In so doing, it allows Brisbane Water to demonstrate due diligence in all aspects of its water supply operations. Th e deve lo p e d HA CC P pla n s su pplemen t the previously implemented process control element of BW's ISO 9000 seri es Quality Assurance system and draw an even stronger focus on iss ues of public health and safety. The H ACCP verification proced ure, by mea ns of regular review, ensu res that the developed HAC C P plans continue to address these vita l issues of pub li c health and safety by addressing current techn ical k nowledge and en1erging issues and trends as they arise.

References Jones M.K. et al (1996) Dairy Processors Ma11agi11g E11 viro11111enta! Risk , QD PI Information Series Q196049

Jones M.K. et al (1996) ls HACCP Eno11gli? The Esse11tial Ele111euts; A I FST C onference, Gold Coast, 5-8 May Codex Alimentarius Commission (1996) Report To The Twe11ty-Ni11t/1 sessio11 of the Codex Co111111ittee 011 rood J-iylime.

The Authors Robert Gray is Manager, Scien tific Analytica l Services, Bri sbane Water, an d Marc Morain is a Food Ind ustry Cons u lta n t, Cen t re for Food Tech nology, a business unit of th e Queensland Department of Primary Industries. R obe rt's e-mail: sas1nbw@ brisbane .qld.gov .au

BOOKS Water in Australia, Resources and Management D Ingle Smith. ISBN 0 19 553704 Oxford University Press, GPO Box 2784 ¥, Melboume 3001. 390 pp, paperback A$65.

David Ingle Smi th , (who now contributes our column Aq11aphemera) was for twenty years a staff member of th e Cent re fo r R eso ur ce and Environm enta.l Studies at the ANU, and as such had access to more data and informed comment than most. Over the past three years he has encapsulated this into a superb book which brings up-to-date a review of the management of Australia's very variable water resources. C hapters deal with how much and where it is, quality, patterns of co nsumption, both urban and agricultural, floods and droughts, and then into policies, pricing, and instituti o n s, w ith comment o n water marke ts, co rpo ratisa tions and the impact of private companies, none of which could have been foresee n in the last co m pre he nsiv e rev iew o f Australia's water by Pigram in 1986 . The text is by no means dry, since it is interlaced thro ughout by his personal co mm e nta ry, w hi ch is summarised in the final chapter. Some 40 pages are devoted to 'Where are we going?' including estimates of climate change and the visions of the Ecumene proj ect, ASTEC fores ightin g and D IST recommendation s. This is no lightweight work, it deserves a place o n th e bo okshelf of everyone concerned with water, whether urban, agriculturist or ecologist, fo r serious reading and reference.

EA (Bob) Swinton


m

BUSINESS

EXCELLENCE THROUGH CONTINUOUS IMPROVEMENT 'Connectaflow' M Hill, D Deere and G Hansen Abstract A case stu dy is d esc ribed wh ere Co n tin uo us Impro ve m e n t has b ee n appl ied to a relatively simple main tenan ce o p e ratio n , i nvo lv ing p a r tn er org an isation s, contra ctors, custome rs and staff in the design o f a pac kage for reliab ly and safely pro vidin g a tempo rary water supply to a reside nce .

Introduction E ffec tive qu ali ty ass uran ce (QA ) systems provide contro l, co nsisten cy and trac eabi lity to an organisation's operations. A number o f generic tools have been developed fo r this purpose, the m ost wid ely used be ing th e ISO 9000 se ries. ISO 9000 systems do not necessarily e n s ure th a t risks are ap p ro pr iate ly m anaged and o ngo ing improve me nts take pla ce. T hey do, however, provide a so lid springboard fo r improve men t by giving an esse ntial discipli ne and consiste ncy o f app roach. T his enables control of identified risks and adopti on of impro vem ents in a planned and sustai na bl e mann er. T h e c u rre nt s ta nda r d Au s tra lian Sta n dard refe rs to ISO 9000: 1994. The n ew ISO 9000:2000 has bee n updated to i n clud e co nt inu ou s impro v ement elem e nts. This is seen as a very positive step and th e use o f contin uous improvem e nt withi n quality managem ent already fo rms part of the Busi ness ExcelJe nce Fra m ework. South East W ater Limi ted (SEWL) gained ISO 9000 certification fo r its total business less than a year aft er the am.algamation that lead to its fo rmation in 1995. SEWL has gone on to apply continuo u s improvement as part of its adoption o f the B usiness ExcelJ ence Fram ework. SEWL was the fi rst Australian wate r busi ness to win a Australian Qua lity Aw a rd (AQA) for Busin ess ExcelJe nce in 1998, o ne of only four such awards attained in that year. The C o ntinu ous lm.provemen t cycle is illustrated in Box 1.

Box 1: Cont inuous Improvement Process prop erty . T hi s ca n go on fo r so m e time w he re works suc h as tree re m oval o r road cl os u r es a nd e x ca va t ion a re requi red . T o avoid in con venie ncing the ir c ust o m ers, wa te r u ti lities ca n conne ct a te mpo rary wate r supp ly by rem ov in g the water mete rs fro m the property und er repair and an adj ace nt property. Th e two pro pe rties are th en co nnec ted toge the r to e n su re a co nsistent su pply of wate r.

Fo r m an y yea rs the p rocess of supp lyin g two properties fro m on e service pip e remained un chan ged. H oses and fi ttings used for th is pu rpose we re simply carried arou nd in th e back o f mai ntenance vehicles. This made th em pote n tially su bj ect to damage and entry o f fo reign m at e ri al. F urth e r mor e , t h ey we re uncon trolled and u ntraceable w ith th eir previo us uses unaccou nted fo r . Th is had wate r quali ty risk imp li catio ns. A public

Case example - Connectaflow A rece nt e x ample illust rates th is process . During repai r or re p lace m ent of a property service pipe, it is o ft en n ecessary co i n te rr up t supp ly to a

Figure 1: The traditional tem porary water supply connection presented a trip hazard and was poorly controlled WATER JANUARY / FEBRUARY 2000

43


BUSINESS

Figure 2: Connectaflow is supplied as a hygienically sealed package (left) containing all the elements required for its installation (m iddle) and kee ps the customer in cont rol (right) safety implicati on was also noted w ith hoses o ften lying untethered across foot pa ths and dri veways (for examp le, see Figu re 1). One o f SEWL's fie ld auditors, R on Peters, identified this as an Opportunity fo r Im provement. An Imp rovemen t Team was pu t together that included SEWL Field Services staff and maintenance crew staff fro m a partner o rganisa tion, T hiess Environmental Se rvices (TES, SEWL's principal contractor fo r water and sewer se rvices). Th e team was kept small, to allow full participation

and ownership . By keeping the team diverse, a broad range of ideas were proposed. Above all, staff that wou ld become day to day end-users of the improved pro cess were responsible for its improvement - ensuring a practical and effective solution. T he team aim was to develo p a controlled system for temporary service t h at was qu ick a nd easy t o insta ll/ remo ve, ensu red water quality, provided custo mer contro l over the supply and w ould not presen t a pub lic safety hazard. A number of solutio ns

Environmental and Water Industry Specialists • • • • •

asset management w ater and w astewater technology risk management infrastructure planning strategic partnership

Contact Andrew Osborne or Peter Everist Tel 03 9694 1200 Fa x 03 9694 1211 Web www. fisherstewart.co m. au

I

Quality

Engineers • Surveyors • Proj ect M anagers • Planners • Envi ronmental Consu ltants

MELBOURNE • CANBERRA • BRISBANE • JAKARTA • SINGAPORE • HANOI

44

WATER JANUARY/ FEBRUARY 2000

Endorsoti

Company

M9001UC1166 StwdllmllAualralia

were tentatively developed and field tested . Com ments were so ught fro m both field staff and customers and with t h ese co mm e n ts on b o ar d, t h e Improvement Te am set tl e d on a solution that they named Con nectaflow (see Figure 2). C o nnectaflow utilises only materials and fi ttings suitable fo r potable water use. It comes as a comple te hygienically shrunk-wrapped package that incl udes all th e pip es and fi tti ngs required. In addition to ensuri ng water qu ality, it looks professional and thus provides custo mers w ith confidence. C lips are incl uded in the package to secure the hose and reduce the risk o f tripp ing. Control valves have been added to ensu re eac h customer has con trol over their own water supply in case they need to turn it on or off After use, the fi ttings and hoses are retu rned to the ir man ufacture r for cleaning and sterilisatio n before repackagin g fo r t he nex t use. Eac h package is numbered and co ntrolled through the quality m anage ment system to ensure traceabili ty and provide a historical record . In conclusion, the successful developm en t of Connectaflow is an examp le of t h e u se of t h e Con ti nuous Improvem ent process. Work pro cedures that have been in use fo r man y years are questioned and improvem ents made. The basis for success is teamwo rk between partner orga nisations, contractors, custo mers and staff This ensu res the developn1ent of efficient and effective solutions.

Authors Ma l Hill is Se ni o r Co n tracts Manager, Sewer and Water, Dr Daniel Deere is Manager, W ater Quali ty and Geoff Hansen is Q uality M anager at South East W ater Lim ited. Contact: Malco lm .Hill@sewl.com .au


AWA CRUCIAL ROLE FOR MEMBERS AW A relies almost entirely on the active sup port and involvement of its members to ach ieve w hat it does. As for any membership organisation, ours stands or falls on the fact that me mbers are willing to pay to belong, then take part in the association's activities. T h e recent name change, from the Australian Water and Wastewater Association to just the Australian Water Association , signals the inte ntio n to be inclusive and not to lean towards any part of the water cycle. It also reflects growing awareness o f the fact that there is only one water resource, regardless of where in th e cycle water happens to be when we get invo lved.

Categories and Costs M embership of AW A is open to smdents, individuals, retirees and organisations. Any queries can be directed to our national, localcall number 1300 36 1 426, o r visit our web site at http: / / www. awwa.asn.au (it takes a w hi le to amend the url from awwa to awa, in case you were wondering). Subscription rates are as fo llows:

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published si nce 1988, is being changed to the A11stmlia11 Water Directory. This will include corporate members of the Australian N ational Com mittee on Irrigation and Drainage (ANC ID), The Stormwater lndust,y Association (SIA) and the Water Services Association (WSAA), making it a much more comprehensive publication.

New Members Since the last issue of Water the following new members have joined and we welcome chem all in to the AW A fam ily:

NEW CORPORATE MEMBERS

Apa rt from its own mem bership, AW A's d irection, under new President Alle n Gale, is to collaborate with sister associations as fa r as possible, to achieve commo n goals and to m inimise overlaps. Internationally, that i~ be ing achieved in stronger relationships wit h IW A, t he Internatio nal Water Association. An in-principle agreement has been reached to merge the Australian operation of I WA with AW A, and for AW A to be the national association representing Australia o n IWA.

Mic ro AquaTech Private Bag 1 l-222, Massey University Palmerston N orth, N ew Zealand Ph: + 64 6 350 5993 Fax: + 64 6 350 5688 NSF Internatio nal Level 67, MLC Centre, Sydney NSW 2000 Ph: (02) 9238 627 Fax: (02) 4733 437 Optima tics 7 /62 Glen O sm ond R oad, Parkside SA 5063 Ph: (08) 8271 7053 Fax: (08) 8373 0779 Sulz er Cherntech Australia Pty Ltd 190 Coventry St, South Melbourne VIC 3205 Ph: (03) 9645 7044 Fax: (03) 9645 7099 White International Pty Ltd PO Box I 096, Waterloo D divery Centre NSW 1440 Ph: (02) 9667 0044 Fax: (02) 9313 4225

ATA Scientific PO J3ox 1005, Sutherland NSW 1499 Ph: (02) 9543 0477 Fax: (02) 9543 9459 A rup Stokes (Ove Arup & Partners) 431-439 Kin g William Str, Adelaide SA 5000 Ph: (08) 8212 5580 Fax: (08) 8212 5590

NEW INDIVIDUAL MEMBERS ACT

Australian Leak Detec tion PO Box 1345 , Southport Q LI) 421 5

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Ph: 04 12 764 83 1

New Sou th Wales

Civiltech Pty Ltd 81 Downs Street. North Ipswich Q LD 4305 Ph: (07) 38 12 25 77 Fax: (07) 38 12 2081

M Burke, P Haines, 13 H ooper, 13 Luc, G N ewton, W Timms, J Towns

Quee nsland

Clean T e Q P ty Ltd 38 Kimberly R oad. Dandenong VIC 3175 Ph: (03) 9706 4122 Fax: (03) 9706 4050

A Foley, K Giles, N Gombert, A Kleinschmidt, C Ma, Stephen Tucker, D Weier, I) White

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South Australia

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G-Tech Separation Pty Ltd 2 Raymond Street, Speers Point N SW 2284 Ph: 0408 508 535 Fax: (02) 4950 8036 George Fisc her Pty Ltd 12, 11 - 13 Bay Rd, R ussell Lea N SW 2046 Ph: (02) 9713 7224 Fax: (02) 9713 6029

Vic toria D Evans, R Pelling, Jenni R ohde, R Sto ne, M Thurio w , C Vrazanis

Western Australia S Feaver, L M o linari , K Third, S Triner

Keenrule Pty Ltd 11 /57 Auburn ls.d, R egents park N SW 2143 Ph: (02) 9738 8400 Fax: (02) 9644 4696 Lawson and Treloar Pty Ltd PO Box 115, Ashgrove QLD 4060 Ph: (07) 3366 041 1 Fax: (07) 3366 03 16

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CONTACT US For more in fo rmation or contributions to this membership page, contact our Membership Administrator Merrilyn Bartlett o n 1300 361 426 or mbartlett@awwa.asn.

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WATER JANUARY /FEBRU ARY 2000

45


WATER

1998-1999

Water treatment options for Cryptosporidium and G iardia B M urray, K Linnemann , K Craig

WATER Water Resources Cyanobacteria in a small tropical reservoir D J G riffiths, M L Slaker, P R Haw kins

Jn11

1998

C reating sustainable urban water resources I Lawrence 1\llar 1998 Radon-222 concentrations in potable groundwater, Australia A L H erczeg, J C D ighto n M ay 1998 Wate r in the G reat Artesian Basin R Cox, A Barron ]11/y 路1998 Phosphorus inputs to a reser voir in Orange, N SW M H Chowdhury, D A Bakri ] 11/y 1998 Dissolved organic matter in reser voirs: A review KM Spark May 1999 A d irty water story

B W Go uld

INDEX

)11/y / 999

CSIR O 's U rban W ater Program: A natio nal approach A Speers Sept 1999 Effects of Radiata pine plantations on a small catchment, C ro ppers Creek L 13ren, P H opmans, D Flin n Sept 1999

Water Supply Who Drinks What? Potable water u se in South Australia J S H eyworth, E J Maynard, D C unliffe ) mt 1998

Co ndition assessment of large diame ter water mains J Dymke, P Ferguson Sept 1999 T ele pho ne survey of w ater consume rs R T hurman, K Smith , R Fo rd, S Skerry, W G richtig Nov 1999

Water treatment Use of water treatmen t sludge M Ahmed, C D Grant, J M Oades, P T arrant M ar 199 8

A m obile water treatment plant for small town suppl ies N H ealey May 1998 Rural wate r treatment in South Australia E A (Bob) Swinton )11/y 1998 Ri verland's C ITECT SCAD A system D Steele )11/y 1998 Advanced water treatment without chemical coag ulants M M untisov, J Stewart, K H orlock Sept J998 Arsenic rem oval fro m drinking water M C hapman Sept 1998 Bacterial regrowth potential: M ea sure ment by ac etate carbon equivalents N Wither, M Drikas Sep! 路1998

Mar 1999

Biofilms in water: Influence of organic carbon and disinfectio n M L Angles, J C handy, G Kastl , ] 11/y 1999 V Jegatheesan, P C ox, I Fisher MIEX DO C process launched in WA M Bourke, M Slunjski N ov 1999

Water Quality How sa fe is bottled wate r? R 13 T hurman, S J Ske n)'

Mar 1998

C ryptospo ridium and water: What d o we know 13 R obertso n, M Sinclair, M H ellard, C Fa irley ) 11/y 1998 C ryptospo ridio sis fro m public swimming pools D Lightbody ) 11/y 1998

Effluent Re use Greywater recycling in W e stern Au stralia B D evine, 13 13o wdeen, J E Sch lafrig. rt J Fimmel Mar 1998 Sydney Water Facto ry: W hy> P Longfield

Sept '/998

Effluent reduction options for Easte rn Treatment Plant, M elbo urne M Kozicki , A Antonio u Sept 1998 Health risks of medicinal re sidues, M ore questions than an swers N o11 1998 D Wiesner Gro undwate r co ntamination fr om e ffiu enc irrigation V O Snow, P J Dillo n, W J Bond, C J Smith, 13 J Myers Mar 1999

A new method for analysing off-flavours in drinking water Sept / 9 98 D Graham, K Hayes

Effluent irrigation in Queen sland: Modelling sustainable loading rate s X Hu M ay 1999

Early detection of outbreaks of water-bo rne gastroenteritis A Padiglione, C I< Fairley N ew 1998 Safe drinking water: Are fo od guidelines the answer? D Deere, A Davidso n Nc)IJ 1998 Iden tifying Cry pto sporidium using DNA methods U Morgan, R C A Tho mpso n Mar 19 98 Bioavailablility of Aluminium in alumtre ated drinking water J Stauber, C Davies, M Adams, S Buchanan, T Florence Mar 1999 N ew legislation: Should water really be tre ated as food? D D eere Comparison of C ryptosporidium and G iardia guideline s D Deere N ov 1999

Waste water reuse: Feasibility ... for .,. parks, gardens, golf co urses in Perth E J W ajon, S Ke nway, A Maus )11/y 1999 Storing recycled water in an aquifer: Benefits and risks P Dillon , S T oze, P Pavelic, S R.agusa , M W right, P Peter, R Martin. N G erges, S l"l..inck- Pfeiffer Sept I 999

Biosolids R euse of sludge from a dairy fac tory lagoon P l"l.. L Masse, L V l"l..awlinson ) 1111 '/ 998 D cwate ring and stabilising sludge M Laginestra l\lov I 998 The wonder of worms for sludge stabilisation M Lotzof Ja11 1999

ENVIRONMENT M inimising the impact of pesticides on rivers. T h e cotton industry N Schofield, V Edge, R Mo ran )mt / 998

WASTEWATER Treatment The c osts of Australian BNR plants K J Hartley Jm1 路/998 Werribee tre atment plant, Born 1887 E A Swinto n )mt 1998 Retrofit of a trickling filter plant to BNR standard S Morgan, R Farley ) 1111 1998 V FA Produ ction in Australian and C anadian pre ferm enters E v M unch, F A Koch j,111 1998 O n-line proce ss monitoring of nutrients in

BNR plants

Lime crystallisation for softening water and reducing salinity B Moulds. D H owes ) mt /999

Design of aerated wastewater treatment systems for on-site H 13 D harmappa, M A Khali fe )11/y /998

WATER JANUARY / FEBRUARY 2000

T he ZELflocc process: A low capital cost option for nitrogen removal I< Barr, C A 13althes Nov 1999

Water quality to 20 00: Is Australia leading the w ay? C K Fairley, M I Sinclair Sept J998

Size is important (NOM) G N ewcombe, C Pelekani, C Hepplewhite, K Nguyen Nov 1998

46

T rialling the C D S screening system on raw sewage N W Swain, R A Jago Nov 1998

I D Mc Elvie, G J C ross, T E H arris, 13 T Hart May 1998

A mode l for co ntinuo us tracking of wetland performance J Fabian Mar "/ 998 R e ducing phosphorus in aq uatic streams using m odified clays G B Douglas. D N Coad, J A Adeney Ma y 1998 Enviro nmental Arsenic in rural Vic toria: an update A H inwood, R Bann ister, A Shugg, M Sim )11/y 1998 Environmental mo nito1ing data: W hy? J C ugley ] 11/y 1998 Community consultation at Ag nes Water L M iller )11/y 1998 Mining pollution in d1e King River, Tasmania H Loche r Sept 路1998


WATER

INDEX

1998-1999

Dependence of Australian ecosystems on gro u ndwater Sept 1998 T H a tton, R Evans

C atchment managem ent: Facilitating stakeholder participation J 11..obinson No11 1999

Nutrient release from sedimen ts: The effect of sh ort term anoxia No11 1998 M G h isalberti

CONFERENCE REPORTS

Protecti11g inland waterways: En vironmental management at Lower Molonglo R H ogg, A Wade, A Wijeratne Mar 路1999

BNR3 R Drury, W G C ls.aper, E A Swinto n

Mar '/998

CRC Waste Management and Pollution Jm1 1999 Control The professional environmental research business D E J Garman Performance and commercialisation of C R CWMPC research L l'l___i dge

Phytoplankton m onitoring manual for Australian rivers G Hotze!, R C roome }11/y 1999

Reco verable R eso urces EA Swinton

Sept 路/998

M embrane techno logy I Fergus

C ryptosporidium: W hat next? EA Swinton

Ja11 1999

T rees or bugs? W hich are better for removing nitrogen? Sept 路1999 M Adams, J O liver

Wastewater treatme nt and water reu se F H udman

Impact o f cotton-growing pesticides o n NSW Border lUvers EA Swinton Ja11 1999

The need to improve dewatering technologies S Miller

Bio remediatio n of Atrazine- contaminate d groundwater No11 1999 A Tilbury

A sia Water com es to Sydney C Davis

BUSINESS

Ou tcome fo cussed: Draft e n vironmental water quality g uide lines E A Swinton May 1999

Improved biological treatment processe s .. fundam entals J Keller

Melbourne 's bulk water suppl y agreements B Bayley, T Kelly Jn11 1998 Preventing backflow contamination R Ford Mar 1998 Bac kflow prevention R Tucker, J Coghlan

Mar 1998

Privatisati on , wh o d ecid es? Is. Loo, C Porter

May / 998

A WW A 18th Fed eral Convention V:irious reporters }11/y 1999 En vironmental engin eering research event 98 E A Swi nton Nov 1999 H ow are our catchments managed' R~~

Who w ill train o ur future en gineers? L Reede r May / 998

Mar 1999

~v l ff9

Transferring knowledge: The C ls.C appro ach P C ullen

Gro undwater pollutio n: Can rig hts markets help?

Sho u ld we care abo ut microfa una? R Shiel

} 11/y 1998

Water re use: A standard contract Sept I 998 A Sherman R.isk management strategies for recoverable resources No,, 1998 S Davis. A 11..oche WSAAfacts 1997: A snapshot of the Australian urban water industry Nell' 1998 T Carpenter Valuing options in water supply strategics I' Gerrans } 11/y 1999 Fin e tuning community understanding of th e septic tank B Ridder Jn11 1999 Wate r markets: Buyer and seller perceptions H Bj ornlund, J Mc Kay Water and the GST D l( uhn c

1\1/nr I999

May 1999

Water industry reforms: Pipe dream or nightmare? 13 M c l<.ae Sepr I 999 Experiences with small-scale BOOT projects T La m bert Sepr 路1999 Water licences and property rights: T he legal principles for compensation in Q ueensland P Tan Ne)// 1999

The C ampaspe River proj ect J C rowns Blue-green algae and artificial d estratification J Whittington , 13 S She rman, R L Oliver In va sion of an exotic freshwater snail S Schreiber Cyano bacterial b looms in the Darling River R O liver, C l'l..ees, M Grace, 13 Hart, G Caitchcon, J Olley Salinity: A threat to our stream s and wetlands P Bailey, N Warwick Flooding: T h e lifeblood o f o ur billab ongs I) Nielsen New risk-based water quality guidelines 13 T Hart. W Maher, I Lawrence G uidelines for d esigning pollution contro l po nds I Lawrence, P Breen Assessing water quality in K osciusko NP u sing AusRivAS R H Norris, J Simpson, K Beggs NSW rivers n eed urgent re storation J H arris, P Gehrke, S Hartley Where do carp prosper? P D river

Str ucture of bacterial assemblages: application to process control J Guan , R Amal, T D Waite

May 1998

Mining in the Great Artesian Basin I' 13ow 111an }11/y 1998

M I) Young, I<. Evans

Contaminated site remediation, hazardous waste treatment Is. Wainberg

Advanced oxidation processes and poten tial applications A J Feitz, I<. Aplin, T D Waite

CRC FEATURES CRC Freshwater Ecology

Solid waste management R Wainberg

Waste minimisation and cle ane r production R Wainberg Education , trainin g and technology transfer J Nielsen

CRC Catchment Hydrology

M ay / 999

Meetin g industry n eeds I<. Mein Let's get the h ydrological fa cts straight! J Langford Sou rces of sediments and ph ospho rus in T arago R ese rvoir F J D yer, J M O lley, G A Moore, A S Murray Trees on hills: Bette r growth = less waterlogging R. P Silberstein, D L Mcj annet, l't A Vertessy AQUACYCLE: An urban water reu se computer model G Mitchell, R Mein, T M cMaho n Reducing salt exports fro m an irrigated ca tchment, Barr Creek M Gilfedde r Using radar to predict floods A W Seed, P J ordan, X Sun, l't Srikantlun , J Elliott Trees for profit and a healthy watertable? R P Silberstein, RA Vertessy, J Morris, P M Feikema Techno logy transfer: The thirst for b etter tools and knowledge D Perry

WATER JANUARY / FEBRUARY 2000

47


MEETINGS For information about the events listed, contact A WA Federal Office. Tel. (02) 94 13 1288 Fax (02) 9413 1047 Email irifo@awwa.asn.au AWA CONFERENCES 2000 9- 13 April, Sydney Convention Centre, NSW Enviro 2000: • Fifth Australian W aste Conventio n Fax 02 94 15 J599 • WaterTECH Conference • Greenhouse Conference • Odour Conference

OZWATER & OZWASTE TRADE EXHIBITION 2000 10-12 April, Sydney C onvention & E xhibition C entre, NSW

AUSTRALIA 2000 2-5 March, Melbourne , VIC The International Landcare 2000 Con fe rence Fax (03) 9690 7 155 6-9 March, M elbourne, VIC Coast to Coast 2000, N ational Biennial Coastal Conference, Victorian Coastal Council Fax (03) 952 1 8889 8-10 March, Sydney, NSW T he 6th R enewable Energy T echnologies & R emote Area Power Supplies Confe re nce, the 2 nd World Solar Electric Buildings Con fe re nce and the So lar T hermal 2000 International Conference, Electricity Supply Asso ciation of Australia, Fax + 6 12 924 1 5354 11-17 March, Melbourne, VIC 10 th W o rld Water Congress Melbourne IW R A. UNE, AWA, IE Aust Fax (03) 9682 0288

19-25 February, Dur ban , South Africa 10th Congress, U AWS, UADE Fax +27 225 242629 27 F ebruary-1 March , B osto n Massachusetts, U SA R esiduals and Biosolids Management Confe rence: 13iosolids 2000, WEF Fax + 1 703 684 249

17-25 March , Auckland, New Z ealand Water 2000, W E F, T he Royal Society of N ew Zealand, N ew Zealand Water & Wastes Associatio n Fax +64 9 827 2003 27-29 March, Lancaster, UK Membra ne Tech nology in Water and Wastewater Treatm en t. Royal Society o f C hem ist1y, Water C hem ist1y Fo ru m , The European Desalination Society Fax + 44 1244 3 414 78 4-7 April, Leeds, U K Wastewater Treatment Standards and T echnologies to M eet the C hallenges of the 21st Cenn uy, Yorkshire Water Fax +44 113 233 2 243 10-12 April, Manila, Philippines Sustainable and Humane Cities Inte rnatio nal C onference, The College o f Arch itec ture and Fine Arts of the R oyal and Pontifical University of Asnto T omas Fax 73 1 4343 28 May-1 June, Sun City, South Africa W ISA 2000, The Water Institute of Sou thern Africa (W ISA) Fax +27 11 3 15 1258 5-9 June, Ontario, Canada R '2000 R.ecove,y, R ecycling, n.ein tegration, PEAK, Mark ham Fax + 41 I 386 44 45 11-15 June, Denver, Colorado, U SA A WWA Ann ual Conference Fax + I 303 794 77 1 I 3-7 July, Porte Maillot, Paris W o rld Con gress and Exhibition, !WA, IWSA Fax +33 1 47 56 21 I 0

21- 23 March , Sydney, NSW Science 2000, T h e Sc ie n ti fi c Su ppli e rs Assoc iati on of Au st ral ia Fax (02) 9804 8052

9-12 July, Vancouver, British Columbia, Canada Watershed 2000 Abstracts Water Environme nt Fax 703 684 2413

23-25 May, Melbourne Exhibition and Conference C entre, VIC Theme: Water - Essen tial for Life. Contact: Conference Secretariat, PO Box 2349, N orth Brig hton, Vic 3186. Tel (03) 9530 6777 Fax (03) 9530 6526 or e m ail: serviccs@profco nfcrenccs.co111

11-13 September, Helsinki International Dissolved Air Flotation Confe rence in Wate r and Waste T reatmen t, IA WQ, Finn ish Wate r & W aste Water W o rks Asso ciation Fax + 3358 9 1484750

23-28 July, Brisbane, QLD 9th International Con gress for C ulture Collections, Brisbane, QLD ICCC-9, WFCC Fax + 61 7 3365 1566/ 4620

26-29 September, Amsterdam, T he Netherlands Aq uatech 2000, Fax + 31 20 646 4469

20-23 November, P erth , WA 3 rd In t e rn a tional H ydrology an d W ate r n.esourccs Symp os ium , Fax + 61 8 9322 1734

OVERSEAS

8- 12 October, Cartagena De Indias, Columbia 17th American Congress of En viro nme nt and Sanitary Engin ee ring www.acodal.org.co

ADVERTISERS INDEX

2000 30 January-2 February, San Antonio Texas, USA Water R euse 2000, AWWA Fax + 1 303 794 73 10

Enquiries: Telephone (02) 9410 1302 48

WATER JANUARY / FEBRUARY 2000

Grundfos Pumps inside front cover CDS Technologies 5 Orica Watercare 7 Henry Walker Eltin 9 Rolls Royce Australia 10 US Filter 14 Fluidquip Australia 15 Qld Department of Natural Resources 17 Zeolite 19 Ultraviolet Technology of Australasia 21 Equipsuper 23 Egis Consulting 26 Tapex 29 Gutteridge H askins & Davey 31 Nylex Geomembranes 33 James Cumming & Sons 34 River Sands 36 Fisher Stewart 44 BOC Gases inside back cover outside back cover Tyco

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Water Journal January - February 2000  

Water Journal January - February 2000