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AUSTRALIAN WATER & WASTEWATER ASSOCIATION

AUGUST 1994

• Reforms • Environment • Water Quality • AWWA/RACI Supplement '


AUSTRALIAN WATER &WASTEWATER ASSOCIATION

Volume 21, No 4 August 1994 Editor

CONTENTS

E.A. (Bob) Swinton

Editorial Correspondence

ASSOCIATION NEWS President's Message

2

From t.he Executive Director From the Branches

4

5

MY POINT OF VIEW The Community and Water Quality

3

Carol Hamilton

FEATURES •

Development of the 1994 Australian Drinking Water Guidelines

10

J A Cugley •

Effects of Reservoirs on Downstream Aquatic Habit

15

B L Fin layson, CJ Gippel, S O Brigga •

Cooperative Federalism and Water Refom

21

JJ Pigram, W F Musgrave, B P Hooper, J Dudley, M J Bryant 26

M Munrisov

DEPARTMENTS International Affiliates Products Meetings

8

28 28

AWWA/RACI SUPPLEMENT: WATER CHEMISTRY •

Environmental Chemistry: The Needs of Water Quality

1

B N oiler •

Healthy Rivers and Better Catchments

1

JM Swan •

3

Distinguishing Human and Animal Faecal Polluction

R Leeming, A Ball, •

6

Ashbolc, P Nichols

Photocatalytic Oxidation for TOC Analysis

8

P A Bennecc, J C Richards •

Flow-Proportional Sampling of Sewage

10

N H Pilkingcon, J S Bridger •

Editorial Board FR Bishop, Chairman B N Anderso n, G Cawston, M R Chapman, P Draayers, W J Dulfer, GA Holder, M Muntisov, P Nadebaum, JD Parker, A J Priestley, J Ri ssman. ACT - Cynthia Nagy Tel (06) 251 3368 Fax (06) 251 3060 New South Wales - Mitchell Laginestra Tel (02) 412 997 Fax (02) 412 9876 Northern Territory - Jan Smith Tel (089) 82 7244 Fax (089) 41 0703 Queensland - Lyndsay Chapple Tel (07) 835 0222 Fax (07) 832 6335 South Australia - Phil Thomas Tel (0,8) 259 0244 Fax (08) 259 0228 Tasmania - Jim Stephens Tel (002) 31 0656 Fax (002) 34 7334 Victoria - Mike Muntisov Tel (03) 600 1100 Fax (03) 600 1300 Western Australi a - Tony Hendry Tel (09) 497 1344 Fax (09) 497 1281

Treatment of Liquid Cyanide Wastes Disinfection and Water Treatment: Formation of Chemical By-Products

12

14

B C Nicholson OUR COVER

,lleltnM

•hti, ..... 111 ,Wat1111hAlily ,AWWA/11,WS!loplmfft

Our historic photograph shows the bridge over the Snowy River at Dalgecy, ca 1906, when rhe low-fl ow channel was some 75 metres wide. Scream flows at chis site have been dramaticall y reduced as a result of the Snowy Mouocains Scheme, espec iall y by the Jindabyne Dam which began co operate in l 967. The river channel has narrowed considerably and pares of che fo rmer river bed, now exposed, are colonised by largely exotic species such as wi llows (see inset photograph). The effem of such regulation on rivers are discussed in che paper by Finlayson et al (page 15 ).

Historic photograph by ro11rtesy of the State Library oft SW'.

is published six rimes per year February, April , June, August, October, December by

Australian Water & Wastewater Inc. ARBN 054 253 066 PO Box 388, Arrarmon NSW 2064

Federal President Ri chard Marks

Z Slavnic •

Margaret Bates Tel (02)4131288 Fax(02)4131047 A\Y/W A Federal Office Level 2, 44 Hampden Road, Arrnrmon PO Box 388, Arrnrmon NSW 2064

WATER (ISSN 0310-0367)

Polymeric Flocculants in Water Purification

BA Bolco •

Advertising Sales & Administration

Branch Correspondents

REPORTS Meet Melbourne Water

4 Pleasant View Crescent Glen Waverley Vic 3150 Tel/Fax (03) 560 4752

Executive Director Chris Davis Australian Warer & Wastewater Association assu mes no responsibility for opi nions or srarements of facts expressed by contributors or advertisers and ed itorials do nor necessarily represent rhe official policy of the organisation. Display and classified advertisements are included as an informational service ro readers and are reviewed by the ed iror before publication ro ensure their relevance ro the water environmenr and ro rhe objectives of rhe Association. All material in Water is cop)'right and should nor be reproduced wholly or in part without the written permission of the Edi ror.

Subscriptions \Vater is sent to all members of the A\Y/\'(I A as one of the privileges of membership. onmembers can obtain \fft1ter on subscription at an annual subscription rare


MANAGEMENT

DEVELOPMENT OF THE 1994 AUSTRALIAN DRINKING WATER GUIDELINES _a;

J A Cugley* Abstract

related to public health. The larger document provides derail er • To ensure that the document is suffi- how rhe guidelines have been derived for eac" ciently clear and understandable for rele- group of water quality char~cteriscic, com m_vant auth orities to use for community niry consulcacion information, advice on , . management of water supp ly systems ar~ consul carion. Th e Joint Committee estab li shed a how to assess long-term performance, ar_ number of spec ialist pane ls to deal with some specific information for small supph Introduction physical, inorganic, organic, microbiological In addition the document provides face shtt: The Australian Drinking Water Guide- and rad iological characteristics. A sixth panel for each character istic cover ing ho'\\' • lines have be en rev ised in response to a was assigned che important peiformance cwess- guideline was derived, health considerano~ number of stimuli: typical values in Australian drinking w~-. 111ent responsibility. The specialise panels were • The 1987 NHMRC/AWRC Guidelines co mpo se d of peop le wide ly reg ard ed as supplies, methods for removal and mea u-~recommended that the guidelines be rev- leaders in their fie ld in Australia with repre- ment, and some general info rmation inc' iewed after five years. sentat ives from water authorit ies, depart- ing how the characreriscic can gee into ware~ • The World Health Organisation (WHO) ments of water resources, departm ents of Th e su mm ary document co ntain commenced a review of their guidelines health , CSIRO, universities, private industry, introduc tion to the charac teristics of w_:_ · in 1991 and it was evident rim the Aus- a consumer organisation , and ochers. Guide- quality with rabies of guipeline values. T trali an guidelin es would need to be lines for pesti cides were nor reviewed by summary is intended for easy reference. -- _ reviewed and updated. these specialise panels as they were covered the emphasis is on presenting information • The Australian and ew Zealand Env i- by rhe HMRC Pesticides and Agricultural a broad range of people. ronment and Conservation Counci l were Chemicals Standing Committee. The guidelines are a user-needs spec1.' -independently developing water quality The guidelines document is one of a series ciao on what constitutes good quality dn- guidelines in a number of areas, including being produced under rhe arional Water ing water from both a health and an aesthcraw water for drinking water supply. QuaIi ry Management Strategy. One of these viewpoint. They therefore conce ntrate Ir was therefore timely char a review of documents, viz "Australian acer Quality for water quality at the point of use (the kit ... the drinking water guidelines be undertaken Marine and Fresh acers" , QMS 1992), cap, shower rose ere). Th~s does nor, ho'\\ t· . and in 1991 the Australian Water Resources contains information on drinking water based mean char the water authority is respon_.. Council (now pare of the Agricultural and on the 198 HMRC/A~ RC Guidelines. for problems caused by poor pl um bin.,: • Resource Management Council of Australia This information will be superseded by the other facrors wi thin rhe consumers properr and New Zealand) and the National Health new drinking water guidelines. The gu id elin es are nor, and were and Medical Research Council sec up a Joint The form at of che new guidelines is differ- developed to be, legally enforceable Committee to oversee rhe process. The terms ent from char of the 1987 gu idelines. Ir is <lards. They can, however, be used as a of reference were: based on the Canadian Water Quality Guide- for preparing or negotiating regional • To produce drinking water gu id elin es lines document (CCREM 1987) and consists clards of serv ice . Ir is antic ipated that • that have broad acceptance as an au rhori- of a large loose leaf style document and a tari ve guide for the prorecrion of public much smaller summary document. The loose *John A Cugley, Office of the EO\r health. leaf scyle of the larger document has been • To produce drinking water guidelines for adopted to facil itate the insertion of updates ment Proreccion Authority, GPO Box 2 Adelaide SA 500 1 aspects of water qu alit y nor direc tl y when new information becomes available.

This paper, by the research officer to the J oint Comm ittee set up by NHMRC and AWRC (now ARM CA Z) , discusses the rationale behind some of the major recommendations.

0

The (1994) Australian Drinking Water Guidelines have just been released as a draft for public comment . They arc published in two volumes: • Summary Document (A4, 38 pages) • Full Guideli nes (looseleaf binder, 300 pages)' Boch are available free of charge from: Cathy Clutton, Environmental Health, Department of Human Services anc Health, GPO Box 9848, Canberra ACT 260 1. Fax (06) 289 7222 The University of Wollongong has been appointed co oversee the publi c consultation process. Submissions shou k be addressed, BEFORE 31 OCTOBER 1994, co: Professor John Morrison , The Environment Research Institute, Univer it:. of Wollongong NSW 2522. Fax (042) 21 4665 10

WATER AUGUST.~~-


process will be undertaken by wacer authorities in consultation with local communities using the guideline documents as an authoritative reference. The remain der of thi s paper discusses some of the signifi cant technical points to arise out of the review.

Microbiological Guidelines The guid elines emphas ise the need fo r adequate barriers to stop contamination of dri nking water supplies. The use of barriers is, of course, not a new concept and it is not intended chat it should be seen as such. However in establishing new guidelines it is possi ble to gee so engrossed in the detail chat th e fu ndamental unde rl ying ob jec tive is obscured. As effective barriers are undoubtedly the most important step in ensuring che mi crobiologica l quality of drinking water supplies it is fitting chat they are listed at the rap of the guidelines. Monicoring of the microbiological quality is a secondary, albeit very important, step bur should be seen in the context of ensuring chat the barriers are working properly. Moniroring, by itself, will nae guarantee the safety of drinking water supplies. In che same way chat barriers are used to scop contamination from entering a system, monitoring for possible bacteriological contamination involves a number of related steps, each of which is important: • ensuri ng chat an adeq uate number of sampies are analysed fo r bac teri ological quality; • the use of two ind ica tors, as a safe ty nee, co indicate the possible presence of pathogens; • cak ing imm edi ate seeps upon detection of contamination co ensure that publi c health is not compromised; • the evaluation of performance over tim e co identify and rectify poorly performing systems. The guidelines deal with eac h of these seeps and contain explanations and justification for the measures proposed. A num ber of ques tions are often posed wh en micro bi ologica l gui de lines are discussed. Some of these have been the focus of public debate for quite a while and were discussed at considerable length in expert panel deliberations. It is therefore worthwhile discussing some of them in detail below. Which Indicator Organisms Should Be Used, And Why? Although

and chermocolerant coli forms (or alcernatively Escherichia coli). In using boch chese groups ic is recognised thac nei cher is ideal. Total coliforms can be presenc when chere is no faecal contaminacion. They can occur nacurally in soil and vegetarian, and can be present in drinking wacer supplies as a resulc of che growch of biofilms on pipes and fictings, or chrough leaks, frac cures or repair work. Des pice chese draw- backs they are useful because: • as a group they include E coli which is a direct indicator of faecal contaminacion; • cheir high numbers in faecal macerial, and cheir abi licy to survive fo r a long rime, means char chey can be useful in indicacing more remoce or less recent incidents of faecal contaminacion; • cheir decection can indicace char condi cions may favour ch e prese nce of free living pocential pachogens; • cheir relaci ve abund ance and hardiness makes chem a useful indicacor of che efficiency of wacer creacment and disinfect ion processes; • cheir absence is a good indicacion chat the barriers co contaminacion are working; • where faecal contaminacion has occurred, coral coli forms are usually more abundant ch an ch ermotol era nc coliform s (chey cannoc of course be less) and hence may be easier co detecc when contaminacion is ac a low level. Of all che coliforms, E coli is che most specific indicacor of faecal contaminacion generall y ava il able . Alchough cherm oto lerant co li fo rm s are a mo re spec ific indi cator of faeca l conraminacion chan coral coli fo rms, chey are less specific chan E coli as chey are a relacively mixed group of organisms; some of which come from environmental sources. So why allow boch chermocolerant coliforms or E coli 1 The reasons are as follows: • ch e grea t majoricy of therm otol eranc coliforms are E coli; • tes cs fo r cherm oto lerant coli fo rm s are cheaper and quicker chan cescs for E coli; • a posicive fi nding for eicher organism will lead to the same response. The use of thermocolerant coliforms may lead co che occasional posicive result without faecal contamination being present, but che slighcly cheaper cost of analysis may be worth the chance of this occurring. It is reasonable therefore to allow water authoricies co decide which rest best suits cheir needs as a posicive findin g fo r ei ch er will in vo ke ch e sa me response.

indicacor organisms have their disadvantages th ey still prov ide the mos t cos t effec ti ve How Many Indicator Organisms means of determining whether faecal contam- Should Be Permitted?. The 1987 guidei naci on of drinkin g wa ter supp li es has lines specify chat "no scheduled sample should occurred. The coliform group have been used contain any faecal coliforms", buc chat "up co for a long time and a vast amount of experi- 10 coliforms may be occasionally accepced". ence has accumulated on cheir use and che In seccing che new guidelines ic was recoginterpreracion of cesc resulcs. The cescs are ni sed char chere are considerable difficulties relacively simple co do and are reliable. As a associated with specifying a number other conseq uence considerable confi dence can be chan zero. The reasons for chis are: placed in che resulcs. • The in fec ti ve dose for water-born e The guidelines use boch coral coli forms pathogens has nae been esrablished. Some WATER AUGUST 1994

data sugges1i.,chac, for a small number of peop le, inges cing a si ngle pachoge nic organism is sufficient co cause disease eg typhoid and some virus particles (Forsych 1993). As pathogens may be prese nt if indicacors are detected, a guideline based on zero indicacors is a safer alternative. • The num ber of organisms detected in a sample may nae be a crue indication of che severity of contamination of the supply. Contamin ati on may occur in the tim e interval between sampling events so chat samples contain only the tai l-end of the contamination. For example, in a serious typhoid outbreak in Detroit many years ago mean coliform counts on two successive days were only 3 and 10 organisms per 100 mL (Forsyth 1993). • Specifying a number pre-supposes chat it can be accurate!y measured and that the result of a measurement on a sample will be representative of the water quality in the supply. Replicate analyses on portions of samples have shown that there can be considerable variation in che number of organisms detected between replicates. Mi crobiol ogical cescs are therefore not precise measurements and it is diffi cult, if not impossible, to provide sc ientific justifi cation why a number such as 10 per l00mL should be used in preference to say 5 per l00mL, or any other nonzero value. • Although mioobiological tests for indicator organisms may not be precise they are very reliable in establishing whether indicacors are present or not. False posirive or false ;egacive results are known to be a very low occurrence. It is recogni sed chat setting zero as an a_cti on leve l is a ti ght ening of th e 1987 requir ement s but it co nform s with th e approach adopted by the WHO, and provides a higher degree of assurance that the water is safe co drink. What Action must be Taken on Detection of an Indicator Organism? If a positive result is found for either

chermotolerant coliform s or total coliforms then the guidelines require immediate steps to be taken to investigate and/or rectify the problem. The presence of thermocolerant coliforms (or alternatively E coli) is a definite indication of recent faecal contamination and should be acted on immediately. If a sample is positive for chermocolerant coliforms (or alternatively E coli) then another sample must be taken from the same sire and reseed for both indicator organisms and , at the same time, disinfection increased and/or an investigation undertaken to determine the possible cause for the contaminati on. If the repeat sample is also positive for eicher indicator organism , then increased di sinfec tion and a full sanitary survey is required. The action required on detection of a positive result for coral coliforms, in the absence of chermotolerant coliforms, is slightly less 11


practical monitoring program will occasion- Aesthetic Guidelines for ally detect an indicacor organism. This may Physical anc:I Chemical be due co occasional fa ilure of disinfecrion Characteristics eq uipment, less rhan a 100% kill rare, contaThe new guidelines seek co defin e good mination of the sample container, and ocher quali cy wa ter because chis is und oubted ly reasons nor directly re lated co ch e warer consisce nr with expectations of Austral ian quality. When a positive resulr is recorded ir consumers . Th e WHO gu idelines, on ch e is viral char imm ed iate corrective action be ocher hand , seek co define acceptable quali cy raken, bur it does nor necessarily mean char water. In some cases there is a big di ffe rence che supply is unsafe. From a long term per- between what is good and what is acceptable. formance assessment viewpoint rhere is li ttle The aesthetic guidelines were based on poin t in specifying unac hi eva ble require- the concentration or measure of a characterisments. Allowance has therefore been made tic char would be jusr noticeable by cas te, for an occasional positive resu lt. appearance, odour.and 'feel'. In many cases it What, rhen, would be regarded as accept- was possible ro base che guideline value on able performance? There is no unequivocal accepted rasre and odo ur threshold s pubanswer. The new guidel ine for rhermocoler- lished in che literature. These thresholds are ant coli forms requires char 98% of samples che concentration of a chemical char is just be free from contamination . This was based noti ceab le by a trained gro up of people. on rhe following rationale: These data are ava il ab le for a number of • No reasonable sa mpling program ca n chemicals, particularly organic compounds. How Were the Number of achieve zero rhermocolerant bacteria all of For rhe orher characteristics rhe guid eline Samples Determined? Boch the 1993 rhe rime. In facr it can be shown srarisci- va lue was by necessity a subjective judgeWHO draft guidelines and the new guidecally chat a requirement based on meeting ment caking inco account values used elsezero all rh e rime places impossible where; particularly in Canada, the USA, rhe lines base the number of samples co be reseed for indicacor orga ni sms on che populati on demands on mon icoring. EEC and rhe WHO. Perceptions and expecbeing served. Th e new guid elines have a • One isolation of chermocolerant bacteria tations within the communi ty, effecrs on corminimum requirem ent of one sample per per year is che next best alcernacive co zero. rosion of pipes and fittings, build up of scale, week whereas the minimum WHO require- • Th e minimum number of sa mples and staining of laundry and san itary ware ment is on e sample per monch. Wh y the required in a monicoring program is one were also considered. per week and one fai lure in 50 samples difference ? The difference between good and acceptable It is important in any sampling program mea ns chat 98 % are free from contam- is important. For example, where caste and char che results of tests on a relatively small ination. odour dara are available, rhere is usually a volume of water are representative of th e • The performance assessment req uirement substantial difference berween the concentrawater supply, not just at the rime of sampling for chermocoleranc coli for ms (or alterna- tion of a compound char is just noticeable, but betwee n samples. Wirhouc error-free ti ve ly E coli) should be more stringe nt and rhe concentration chat would be regarded measurement of every drop of water it is not rhan for coliform s because it is a more as objecc~onable. Sometimes the difference direct indication of faecal concam inacion. possible co be 100% confident chat chis concan be an order of magnitude or more. dition is met. It is however, possible co be • This 98 % req uirement can be mer wirh a Although setting che aesthetic guidelines 95 % confident, or even 99% confident. The high degree of confidence by a well oper- did nor involve cos t considerations it was ated system and a reali stic and pract ical recogn ised rhar meeting the gui delines may degree of confidence is related co che number of samples analysed. monicori ng program. involve a substantial upgrading of existing Th e requ iremen t for coral co li for ms is supplies in some areas. The cost of improving Ir can be shown sracisrically chat resting a sample a month, even if all samples are free of slightly less stringent than for rhermocoler- supplies may be more rhan the community is contamination, will give no more than 17% ant coliforms, with 95 % of samples required willing ro pay. Ir is therefore important char confidence that the supply is free from conta- co be free of contamination. This is the same che aesthetic guidelines be regarded not as mination (Ellis 1989). Increasing the number as rhe WHO and cakes into account the face absolute, or values over which there can be no of samples reseed co one per week increases char non-chermocoleranc co li fo rms may be negot iation , bur as subj ect ive judgements the degree of confidence co about 65 %. In present natu ra lly in the water supply. The which can be used as a scarring point in dispractical terms, one sample per month allows persistent presence of non -ch er mocolera nc cussions between water auchoricies and cona substantial period for contamination co pass coli fo rm s in the water supply is of concern , sum ers leading co the estab li sh ment of underecced through a system. A sample per however, as it can indicate rhar at lease one of agreed standards of service. The standards of week increases the chance of concaminacion the barriers co contaminati on is no longer service may have higher or lower target levels work ing. being detected. for aescheric characreri srics than che guidePerformance assessment is therefore based lines values. The high expecracions of Australian consum ers for drinking water of good quality on a min imum number of samp les being would also warrant a monitoring program reseed fo r indicacor organisms, at lease 98% Health-Based Guidelines for of rhese samples being free of chermocolerant Chemicals based on ar lease a sample a week. What is the Basis for Assessing coli forms and at lease 95 % of samples free of Guidelines Based on a Threshold. Long-Term Performance? The 1993 coliforms. All conditions muse be mer before For most chemicals rhere is rhoughc co be a WHO draft guid elin es do nor exp lic itl y a supply can be said co meet the new guide- concentration below which there will be no provide guidance on how co measure compli- lines. Those supplies which cannot meet the adverse effects . Thar is, life-rime consumption ance for rhermocolerant coliforms but imply coliform requirement due ro , fo r example of water contain ing rhe chem ical ar chis conchat rhey must nor be present in any sample. biofilm growth problems, muse be carefully centration is safe , or entails zero risk co healch. Tora! co liform s, howeve r "mu se not be eval uated in consultation wirh rhe relevant In practice rhe dererminarion of chis threshold present in 95 % of 100 ml samples raken heal ch auchoriry co ascertain rhe origin of rhe involves a number of assump tion s, often throughout any 12-month period". coli forms. Monicoring of these supplies musr involving extrapolations from experiments on The approach adopted in rhe new guide- . be suffic ient co de tec t any change in the animals. There are, therefore, some uncertainlines was co recog nise rhac a sensible and pattern of coliform occurrence. ties in the determination of a safe threshold stringent rhan for rhe derecrion of rhermocoleranr coli fo rm s. Any regular occurrence of coliforms is, however, a marrer -of concern . Th ere are a number of exa mpl es whe re serious contaminat ion of rhe warer supply was indicated only by rhe presence of coliforms. Consequently, if a sample rests positive for colifo rms rhen another sample musr be collected immed iately from rhe same sire and rested for both indicacor organisms. If rhe repeat sample is positive for eirher indicacor organism rhen correct ive acrion is requi red immediately. The rwo indi ca tors co mpl ement one anorher and rhe use of borh provides rhe besr possible coverage for rhe derecrion of faecal conraminarion, or of rhe breakdown of one of rhe barriers co contaminarion. When indicacors are present rhere is prima facie evidence of a health hazard and imm edia te ac tion is required co reduce the risk co the community.

12

WATER AUGU ST 1994


which makes the concept of absolute safety illusory. Hence it is more accurate co view the thresholds as involving a vanishingly small element of risk (Fawell 1992). Ideally the animal data will be from longterm drinking water srndies in a num ber of animal species where a clearl y defin ed o Observable Adverse Effecr level can be esrablished. Sometim es , however, the only avail able studi es are for ce fee ding or di erar y studies, over periods of 2 years or less, in a fe w anim al spec ies . Occas ion all y onl y a lowest Observable Adverse Effec t level can be established. Setting a health-based guideline valu e involves rev iewing all avail able data and setting quasi-scientific safety or uncertai nty factors to allow for variation s within and between species, the lengrh of the smdy, the narnre of the end-point , rh e extent of rhe database and other facrors. These individual facrors are then multiplied rogether co give an overall fac ror that is usually 100 bm may be 1000 or higher. If there is any doubt, the facrors err on the side of safety co produce a lower guideline value . The health-based guideline values are not hard and fas t numbers and there may well be future smdies that warrant revi sion of a guideline value. It is therefore not appropriate, however attractive it may seem co do so, to vi ew th e guid elin e values as standard s above whi ch an effec t oc curs . Th ere are usuall y substanti al margi ns of safety built into the gui de line values and exceedance of the guideline should be seen as resulting in an erosion of rhe safety margin (Fawell et al 1992). Guidelines for Chemicals Where No Threshold can be Demonstrated.

With compounds for whi ch no threshold can be demonstrated , it can be expected that as the level of exposure decreases the resultant hazard similarl y decreases. For genoroxic carcinogenic chemicals it has been theorised that the initi ating event for ca rcinoge ni city is induction of mutation in deoxy ribonucleic acid (D A) of a somatic cell. Theoreti cally one molecule can cause a muracion which can lead ro cancer, although the chances of thi s happening are exceedingly small. A different approach is therefore necessary ro determine the guideline value for these chemi cals. Th e Au stral ian g uid eline s for the se chemi cal s have bee n deriv ed usin g an approac h whi ch inclu des co nsid eration s of the following: • the limit of determination (the smallest amount that can reliably be measured); • the concentration chat would theoreti cally give rise co an estimated risk of one addi tional cancer per milli on people over a life-tim e, based on ca lculations und ertaken by the WHO ; • a threshold effect calculation , bm with an additional safety facror for carcinogeni city. If the limit of determination is the same magnimde as the ocher values then chis has been used as the guideline value. If the limit WATER AUGUST 1994

of determin ati on is much lower than the heal ch based values then t he lower of the health valu es. in used. Frequentl y the two health values are very close. If rh e health values are mu ch lower rhan the lim it of determination then the lower health value is used bm with a note chat improved limits of determination are required for that chemical; this occurred on ly once for all the chemicals listed in the guidelines. This is a different approach co chat used in som e och er count ries, parti cularl y th e USA , which rely heavily on risk assessment models. These involve often complex mathematical calculations and have been criticised because they fa iI ro accounr fo r biological processes, such as DNA repair and growth rate effects, and involve setting an arbitrary acceptable risk level. In practice, however, rhere are very few chemicals in rhe guidelines for which there is no clearl y es tablished threshold for adverse effects. An example is the known carcinogen benzene.

Performance Assessment for Chemical and Physical Characteristics

a minimum ~ 1mber of samples in order ro reduce the possibility of poor performance. The approach preferred in the new guidelines is: • To display data for important characteristi cs in a control chart fo rm at (APHA 1989). This form at shows each result, the guideline value, and a control limit. The conrrol limit for eac h characceri sti c is based on statistical assessments of previous data and , if the system is in control, a large proportion of res ult s would be expected to fall below th e limit. Th e bigger the difference between the control limit and th e guid eline the greater the confidence that the guideline value will nor be exceeded. • For non-health-related characteristi cs the upper confidence lim it of the mean value of res ults for the period should be less than the guideline value. For these characteristics, the guideline values are generally not hard and fas t numbers bm are subj ec tive judg em ents chose n from a range of values. It can therefore be argued that it is th e mea n th at is im portant although sudden changes may be signi fi cant ro the consumer. • Perform ance could nor be regarded as sacisfacrory for health-related characteristics if the guideline values were exceeded on any more than the ra re occasion. Thi s is consistent with , the requirement that the upper confide nce limit of the 95 th percentile of results for the period should be less th an th e guide line. In practi ce, it would t'le di fficult to meet thi s requirement if more rhan one result was above the guid eline value. In addition it can eas ily be demonstrated stati sticall y that poorl y performing systems will require more moniroring than good systems - a clearly desirabl e simation . • The minimum sampling frequency should be determin ed from a stati sti ca l assessment of all the data (Ellis 1989). Doubtless thi s new approach wil l invoke som e di scuss ion, bur at least it provid es a rational basis for assessing perfo rmance with confidence limits for the data. This has not been avail abl e previou sly. Use of co ntrol charts is important as consum ers can see clearly how many measurements have been und ertaken for th e reporting period , the number and magnimde of departures from th e guidelin e valu e, and wh at would be expected based on the long-term performance of the supply.

Ic was recognised rim the guidelines will be used in two separate but complementary ways: • as accion levels; • for assessing long-term performance. There will inevitably be occasions when the gu idelines are exceeded. Each such event mu st be assessed and appropri ate action taken. For example if the guideline value for a health-related characteristi c is exceeded, the accion should be co immedi ately reduce the ri sk co consumers and co consult with local health authorities. If the characceriscic is not related co health then the community may need co be advised about a possible deterioration in water quality. The act ion required co address a short term devi ation from th e guidelin e should not be confused with the need co assess longterm performan ce. \X/h en used for performan ce assess ment purpo ses th e darn are largely of hi srorical interest and any resulting ac tion co im pro ve qu alit y will ge nera ll y be longer term. In the absence of any previous guidance on how to assess perform ance it has been common practi ce by water authoriti es co quote the percentage of sc hedul ed samples reseed for a period (usually over a year) char are below the guideline value. There are a numb er of probl ems with th is t ype of approach: • Ir is imposs ibl e to know wh eth er th e Concluding Remarks results are an adequate represenrarion of In this paper I have concentrated on a few the water quality for the period . of the many technical issues associated with • Th ere is no way of estimating the true the development of the revised guidelines. maximum value. Any sampling program The li st is by no means com prehensive and will on ly provide a biased estimate of the there are man y areas covered in the guidetrue maximum and it will invariably be lines that have nor been addressed including: underestim ated. • Radiological quality of drinking water; ·• Ir may persuade water authorities co rake • Sys tem man age ment con sid eration s 13


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Acknowledgments I thank a number of members of the Joint Committ ee for th eir enco urage ment in prompti ng me to write this article and for providing critical comment on the content. In part icular I thank Messrs Doug Lane, Ken Wright , Kerry Jones, Adr ian Farrant, Don Bursill and Drs Scott Cameron and Ian Calder.

References APHA (1989) Standard Methods fo r the Examination of \Xiacer and \X/ascewacer. American Public Heal th Association, 17th Edition, Part 1020. CCREM (1987) Canad ian \X/acer Quality Guidelines. Canadian Counci l of Resources and Envi ronment Ministers , Ottawa.

Ellis JC ( 1989) Handbook on the Des ign and lncerprecacion of Monitoring Programs. Water Research Centre, Medmenhan , UK, Report NSl9 Fawell JK and Miller DG (1992) Drinking Water Quality and the Consumer. ) of the /11slit11tio11 of Wa ter"'"' E11 11iro11111eutal M,111age111e11I, 6, December, 726-73 1, Conference paper. Forsyth JRL (199.l) The Microbiolog ical Quality of Water. \Yin/er, J of Amtm li,111 Water t111d \'(l,,s/eu'f/ /er Assoc, April, 199.l. NWQMS (1992) Australian \X/acrr Quality Guidelines fo r Marine and Fresh Waters. National Water Quality Management Strategy, Ausualian and New Zealand Environment & Conservation Council.

Author

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MEAS uREM ENT

including dis~ fecrion; • Advice for operacors of small water supplies; • Advice on monicoring of water supplies; • Reporting of resul ts includi ng advice on event, annual and operational reporting; • Commun ity consul tation and customer sarisfacrion. Revision of rhe drinking water guidelines has taken approxi mately 3 years ro complete and involved a fundam ental overhaul of the earl ier 1987 guidelines . Ir is based on rhe 1993 WHO Drinking water guidelines bur also cont ains rhe di stil led wisdom of a number of Ausrr; lian experts. In a number of areas, such as perfo rm ance assessm ent, ir breaks new ground . Whether it will be seen as a major step forward in rhe promulgat ion of drink ing wa ter qua lity and a bench mark fo r futu re guidelin e docum ents, or as a ve rbose and techni cally obruse document of use on ly co the scienti fic and technical elite, has yet robe determined. I hope rhe form er rather than rhe latter.

ACN 004 560374

~ oll'lt>isphere laboratories

Dr J ohn Cugley was the research officer to the Joint Comlllittee respomible for the develop11tent of the Drinking Water Guidelines. He resourced and assessed background material 011 health and other ismes, prepared papers for consideration and review by the expert working panels, and provided specialist advice in the chemical and pe1fom1a11ce assessment areas. John was previo11sly a Senior Chemist at the State Water Laboratories in Sollfh Australia and is now the Principctl Advise1; Water Q11ality, with the Office of the Environment Protection Authority. WATER AUGUST 1994


Environmental Chemistry Continues to Meet the Needs of Water Quality It is now generall y accepted that environmental chemistry is an establ ished discipline and th at environmental chemists have th e specific role of understanding the processes of chemical species in environmental systems, the monitoring of such species and their control to minimize impact. The role of the environmental chemist can be exemplified by current needs for the various classes of aquatic systems. There has been a progressive move in Australia towards the development and implementation of water quality criteria to control the impact of substances added to natural waters . This development is simple enough to achieve and can be improved by incorporating information about chemical speciation to make water quality criteria more relevant to existing physico-chemical conditions for any toxic effect imposed. Environmental chemists would argue that sufficient information about the chemical speciation and processes of any substance in solution will ultimately enable any adverse impact to be controlled . The important step is in understanding how to limit the dispersion of substances in aquatic systems which cause impacts. In contrast, it has been proposed that, in order to fully control any impact to an aquatic system, it is necessary to use biological indicators, particularly invertebrate species, which give an indication of the wellbeing of the aquatic system, through the detection of effects from all chemical species present. Various procedures have been developed which may be based on assessing before and after impact observations. The argument generally used is that such techniques are the only valid approach to assess water quality because physico-chem ical procedures may not detect or measure all significant effects nor

account for synergistic or antagonistic effects. Biomonitoring offers a procedure which is simple to implement but has given rise to difficulties because of the long periods of time required to sort stream sediment samples and to identify species together with changing baseline effects and poor reproducibility. The lack of robust procedures makes it difficult to use biomonitoring for the purpose of water quality control on a routine basis. The current dilemma is how to incorporate the reliability of physico-chemical procedures and hence the regulatory function of water quality maintenance together with an overall indicatio n of aquat ic system well-being given by the number and diversity of species present. Current instrumental developments of ICP-MS for inorganic species and both GC-MS and LC-MS techniques for organic substances make the detection of all significant substances in waters easier to achieve . Procedures which include speciatio n information can be incorporated into · methodology. A proposed solution is to work towards the generation of integrated approaches for aquatic systems which incorporate the best features of both the biological and physico-chemical approaches enabling a more complete approach to be developed. This approach would ultimately lead to sufficiently robust monitoring procedures. It would also seek to break down the current perception that any approach other than biomonitoring alone will not protect the aquatic environment from any added substance. Environmental chemists therefore have a key role to play in taking the lead and interacting with other disciplines in order to achieve the development of comprehensive protocols for the protection of aquat ic systems.

Barry N. Noller (FRACI) Chairman RAC! Environment Division

Healthy Rivers and Better Catchments* John M. Swan,

FRAct

Three years ago I had a novel experience. For the first time in my life I stood for public office. I campaigned in the press, I printed a "How to Vote" card, and with support from my wife and friends I attended three polling stations, shook some hands, spoke to fellow candidates and next day fou nd myself an elected member of the Westernport Water Board. This Water Board is engaged in improving the water supply and providing a major sewerage scheme for nearly all of Phillip Island, and for South Gippsland towns bordering Western Port such as Grantville, Corinella, Bass and San Remo. If you were to ask a chemist which substance out of the millions described is the most remarkable, the most extraordinary, the most unexpected and unpredictable, the answer would have to be water. The seemingly simple Hp molecule is not linear, but is bent, with an angle of 104° between the two oxygen-hydrogen bonds. There are in addition two separate clouds of electrical charge projecting outwards from the oxygen atom. The overall arrangement around the central oxygen atom is roughly tetrahedral. This geometry has some striking consequences, especially because the electron clouds can interact with hydrogen atoms on adjacent molecules, forming so-called hydrogen bonds. If I had more time I believe I could persuade you that the special shape of the water molecule makes life possible on earth. Water vapour is constantly present in the earth 's atmosp here, because of heat from the sun. Again because of their unique structure, the molecules are strong absorbers, and emitters, of infrared radiation. This means that water vapour, as well as giving rise to clouds, rain, hail and snow, is far and away the most important greenhouse gas. Because of this effect, our earth is about 30 °C warmer than would be the case for a dry planet. For the life and health of our growing populations, clean, fresh water is essential. We take this for granted. Yet even in many countries blessed with copious rain, the problem is not water, but clean water. Water fit to drink. In Africa, in much of the Middle East, in overcrowded Asian cities, the situation is already serious. Even in wealthy Australia we face difficult problems of water suppl y. Desalination of brackish water is already an option; the present better • Edited version of an address presented on the award of an Honorary D.Sc. to Professor Swan by Mo nash University on 11 May, 1994 (Supp lement) Water

August 1994 -

strategy is to increase the price of water so as to reduce consumption by stopping waste. At Westernport we have introduced a pay-for-use tariff and positive savings are already evident.

Toxic Algal Blooms A major and increasing threat to water quality is the presence of toxic blue-green algae (cyanobacteria). These so-called algae are actually bacteria which possess many of the characteristics of plants, including the production of toxins which are a health hazard to animals and man. They can grow and reproduce through photosynthesis, and some of them can also "fix" nitrogen from the air and thus require only water, sunlight, carbon dioxide and phosphate for their growth . These cyanobacteria occur naturally in most waters. Factors causing them to bloom, that is, to outgrow their algal competitors, are complex, but are related to excess nutrients, especiall y of phosphate, strong sunlight, and warm water. Windless days are hazardous for water managers; density stratification of the reservoir can lead to release of phosphate from bottom sediments . December 1991 saw a massive blue-green infestation along the Darling River in NSW. In the Westernport Water Board district, the small Candowie Reservoir in the Bass Hills, which supplies all the drinking water to Phillip Island, had to be closed for a week because of an Anabaena bloom. The nearby Lance Creek reservoir of the Wonthaggi-Inverloch Water Board also experienced serious problems. These two Water Boards both realised that they needed to know much more about land use in our catchments, or abo ut land management practices, soil characteristics and possible sources of nutrients. With water board funds and with matching support from the (then) Department of Water Resources, we commissioned the Water Studies Centre at this University, under Professor Barry Hart, to carry out a detailed study of the two catchments over four months in 1992. A Project Advisory Panel was formed, consisting mainly of farmers within the catchments, staff from the two Water Boards, government agencies, and LandCare . We also had a valuable input from three Monash graduate students in Environmental Science, Valerie Masterton, Susan Schneider and David Coleman. The Panel played a

Water Chemistry Supplement

Chemistry in Australia

429


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critical role in identifying feas ible options which could result in benefit both to the farming community and the water boards. Most of the phosphate leached from farms is strongly adsorbed onto soil particles. The key to good catchment management, and to sustainable farm management, is therefore to minimize soil run-off. Land slips and tunnel erosion, bare ground, farm roads and shire roads, are all sources of muddy water, especially after major storms . And loss of nutrients from the soil is the last thing the farmer wants. This year, our Catchment Management Group is exploring some trial options for minimizing these nutrient and soil losses. We have constructed a wetland on Mr Mort Stuchbery 's farm (in the Lance Creek catchment) and a series of silt traps on Stuart and Bronwyn McLaren's farm (in the Candowie catchment). These works will be closely monitored over several years for their performance in the removal of nutrients. The projects are financed by the two Water Boards, a Federal Government grant and State Government agencies. Monash University continues to be involved. I would particularly mention Dr Tony Wong and his graduate student Nicholas Somes of the Department of Civil Engineering who are doing all the planning and design work. Barry Hart's people are doing the chemical analyses. Installation of dairy shed waste treatment ponds is also being pursued in association with "whole farm plans". Interest-free loans for these works are available from the two Water Boards. Tree plantings along streamlines and the associated fencing will commence shortly on a number of farms, with assistance from the Bass Valley LandCare Group. Planting of a major buffer zone of trees around Lance Creek reservoir is well advanced; similar tree planting around Candowie commenced last year and will be extended this autumn. We are trying a new experiment there which again involves Monash. Reservoir managers always welcome strong winds, as these mix the water and this reduces the risk of algal blooms. We do not want our trees to act as "shelter belts". Professor Bill Melbourne in the Department of Mechanical Engineering has been commissioned to design some large- scale "vortex generators" -these could be narrow bands of tall trees or even high fences which if properly spaced could actually focus the wind energy down onto the water surface and increase the water mixing. If this works it will be a quite new management tool. Further studies, involving Dr Paul Bishop in the Monash Department of Geography and Graduate School of Environmental Science, will seek to identify specific land types which 430

Chemistry in Australia

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are at greatest risk of soil erosion. We believe that long-term solutions to toxic algal blooms can only be found in catchment management. So Jong as high levels of phosphate are being washed into the resr;rvoirs, the problem of algal blooms will remain. I hope I have persuaded you that water managers and farmers can find a common purpose in minimising soil loss. It is important to emphasise that catchment management is not a quick-fix option. And it must inv't>lve all the stakeholders -the urban populations, the water authorities, government agencies, industry and the farming community. There must be an active partnership between all these groups in the decision making.

The New Water Authorities The Westernport Water Board will Jose its identity at the end of this year. The government is restructuring the water industry and Westernport will be merged with up to 5 other Boards. The new South Gippsland Water Authority will be run as a business Jed by a Board of Directors appointed by the Minister on the basis of their skills. I do not quarrel with this restructuring, with commercial responsibility being related to river systems and catchments and not to municipal boundaries. But I think we all regret the passing of elected representatives. I would appear to have printed my last " Howto-Vote" card. South Africa has recently demonstrated, should you need a reminder, of the linkage between true democracy and the ballot box. The Minister has suggested that these new water authorities should concentrate on their core business of urban water and sewerage services and should not be involved in waterway management. But water quality starts at the top of the catchment, with the rain fa lling out of the sky. All the land-holders are involved, not just the reservoir managers at the bottom of the system. Land ownership cannot be a licence to exploit and degrade; land owners increasingly recognize that they are custodians of their land. And water authorities are custodians of public health. I hope that the operating licences for the new water authorities can recognize that water managers have to be concerned with soil erosion, with agricultural and land management practices, with the health of our streams and rivers, and not just with cleaning up the water in the reservoir, selling it to the customers, and hoping that algal blooms will go away. They won't.

August 1994- Water Chemistry Supplement

Water (Supplement)

2


Polymeric Flocculan~s in Water Purificalion Brian Bo/to,

FRAct

CS/RO Division of Chemicals and Polymers, Clayton, Vic. 3168 Some water and wastewater treatment processes where soluble polymers are used successfully are : conventional coagulation and flocculation, normally followed by sedimentation and filtration analogous processes where a weighting agent or the like is employed, as in the SIROFLOC approach direct or contact filtration in the absence of a settling stage dissolved air flotation induced air or foam flotation enhanced primary treatment of sewage sludge thickening The approach in this article will be in terms of the molecular species involved, rather than the traditional colloid science or chemical engineering viewpoints. As a beginning, a broad overview based on charge interactions is given, although it is appreciated that this is rather simplistic as there are a few examples where like charged species can coagulate. A deeper interpretation involving specific groups is the next step in advancing the polyelectrolyte cause.

which hydrolyse at the operating pH (-5.5 for Al and slightly lov for Fe) to form metal hydroxide floes . The normal mechanism wh there are high DOC levels and Al doses of >5 mg/L is adsorption the humic substances via a ligand exchange reaction :5

Impurities in Natural Waters

Polymers may be categorized by charge type, which may be cation nonionic or anionic, although amphoteric types also exist. The char density (CD) may be high (50-100%), medium (-25 %) or low (-10' and the molecular weight (MW), is usually defined as high (.!ell medium (10 5-10 6) or low (10 4-10 5). There are strict limits on reage1 which can be used in potable water treatment, especially as regar monomer content in the case of flocculants based on polyacrylamic while those made from epichlorohydrin or ethyleneimine cannot used for drinking water production in Australia. Not all flocculants are synthetic polymers, examples of tho derived from natural products being polysaccharides, especial starches and including cati~ nic starch, chitosan, alginic acid a, carboxymethyl cellulose. Some examples that are commonly met with are itemized belc by their descriptive name and abbreviation, and several structur are depicted below: Polymers that are weak electrolytes, such as tho based on poly(acrylic acid), are approximately 50% ionized und normal operating conditions.

Dissolved Organic Material: The compounds consist of amino acids, fatty acids, phenols, sterols, sugars, hydrocarbons, urea, porphyrins and polymers. 1â&#x20AC;˘2 The polymers include polypeptides, lipids, polysaccharides and humic substances. The humic substances constitute about 60-80% of the total dissolved organic carbon (DOC) in surface waters. Humic substances have unique characteristics because they vary in their acidity, over a pK, range of 3-5 and are polydisperse, with molecular weights of 300-30,000. They vary in their molecular structure, having mostly phenolic and carboxylic acid functionalities, and can behave as negatively charged colloids or anionic polyelectrolytes at natural pH levels. The soluble components in humic substances are made up of humic acids which dissolve in alkali but not acid, and fulvic acids which dissolve in both alkali and acid. The two fractions are believed to be structurally similar, but fulvic acids contain about 10% less carbon and 10% more oxygen than humic acids and are more acidic. Humic acids bind more strongly to metal hydroxide floes than fulvics because large molecules adsorb more strongly than smaller ones. 3 Hence the lower molecular weight forms of humic substances are more difficult to remove by coagulation processes, especially if the raw waters are low in suspended material. Suspended Particulate Matter: Such material causes turbidity and can range in size from colloidal to about one micron (Figure 1). It is an important component of all natural waters. Typical levels are 2200 mg/L, although these can be as high as 200,000 mg/Lin flooding rivers. The particles are heterogeneous in size and chemical constitution, made up of mainly inorganic material such as silica, aluminosilicates and oxides of iron and manganese, and have a substantial organic content, typically 1-20%. The surface properties are greatly influenced by adsorbed humic substances.4 The binding of organics to turbidity particles can be via surface metal ions and the carboxylate groups of humic substances. As there are other carboxylate groups on the same organic molecule which are not bound to the metal, the overall charge on the particle is almost always negative.

Removal of Organics /Turbidity The removal of impurities from water supplies is essential to secure disinfection and to minimize the content of chlorinated organics after disinfection with chlorine. Being negatively charged at natural pH levels, the contaminants can form a stabilized dispersion in water. Conventional coagulation technologies utilize aluminium or iron salts 3

(Supplement) Water

RCoo-+ OH-Al< ~ RCOO-Al< + OHWhen the DOC and Al dose are )ower, the humics are removed a stoichiometric reaction with soluble hydrolysed cationic Al spec (which may be polynuclear) to in effect precipitate an aluminil humate : Rcoo-+ Al-OH++ ~

RCOO-Al-OH¡

The surface charge on the final floes will depend mostly on t dose of metal salt used for coagulation. The size of the floes can increased by the addition of an appropriately charged polymer whi will cause inter-particle bridging to form larger agglomerates. Th< is a vast array of polymers available for both coagulation by char neutralization and for flocculation by inter-particle bridging.

Organic Polymeric Flocculants

Cationic Polyelectrolytes

~ N

DADMAC; Poly(dlallyf dimethylammonlum chloride) medium MW high CD

/"

Me

Me Me

'\~I ~~0: I n OH

DMA/ECH: Polymer from dlmethylamine and epichlorohydrin medium MW high CD

Me AAm/Q: Copolymer of acrylamlde and quaternlzed dlrnethylaminoethyf acrylate (A = H)

Polyethyleneimine Chitosan or polyglucoseamine

PEI

Nonionic Polymers Polyacrylamide Polyvinyl alcohol

August 1994- Water Chemistry Supplement

AAm PVA Chemistry in Australia


Table 2: Polymer Choice for Wastewater Treatment Process Polymer Type CD MW Example

Table 1: Polymer Choice for Water Treatment Process Polymer Type CD MW Example Primary coagulation

H

cationic

L-M

anionic

Coagulant aid

M

H

Dissolved air

DADMAC

flotation

AAm/AA

Foam flotation Enhanced primary

H

AAm/AA

cationic

L

H

AAm/Q

cationic

L

H

AAm/Q

Coagulant aid

cationic

L

H

AAm/Q

Direct filtration

cationic

H

M

DADMAC

alum I Fe 3â&#x20AC;˘

anionic

L

H

AAm/AA

DADMAC

lime

cationic

L

AAm/Q

anionic

M

H H

cationic

M

H

AAm/Q

anionic

H

H

AAm/AA

H

cationic

SIROFLOC

M

Sludge thickening

Anionic Polyelectrolytes

l ]1 ~ CH, -

CH - -

CH, -

CH

C= O

C= O

I

I

NH,

Red mud ex bauxite

AAm/AA: -

I

1

Partially hydrolysed polyacrylamlde or copolymers of acrylamide and acrylic acid high MW low to high CO

O_

X

y

PSSA: Poly(styrene sulfonlc acid) medium MW high co

Poly(vinylsulfonic acid)

VSA

Applications of Polyelectrolytes The main applications are in coagulation/flocculation processes that are followed by sedimentation and filtration, or by flotation. These will be dealt with in turn. Primary Coagulation: In potable water production by conventional coagulation/sedimentation processes, polymers can be used instead of metal salts as primary coagulants and destabilizing agents via a charge neutralization/precipitation mechanism. 6 Being generally negatively charged, the turbidity particles and humic substances will interact with a cationic polymer, the correct dose eliminating the charge so that particle agglomeration is facilitated . A cationic polyelectrolyte of high CD is preferred, as summarized in Table 1, and there is then a negligible effect on increasing the MW of the polymer. Coagulant Aids: One of the major uses of organic polymers in water treatment is as an aid to increase floe size after alum or some other metal salt has been used as the primary coagulant. 7 After coagulation by the inorganic salt, the particles produced may have an overall slightly positive or slightly negative surface charge, depending on the dose of metal salt and the type of raw water. A polymer of opposite charge and low to medium CD is selected as listed in Table 1, the choice of polymer and its dose being determined at the laboratory level by means of so-called jar tests. Provided a high MW polymer is used, this produces large aggregates that settle much more rapidly. The use of an anionic polymer in this way results in a substantial ¡ reduction in the alum dose, as alum is not very effective in removing the soluble organics because the floe particles are small and light and do not settle rapidly.8 This is shown in the dosing of a synthetic solution of 5 mg/L of humic substances with 250 mg/L of alum, which removes only 20% of the organics; when alum at only 10 mg/L is followed by an anionic polymer at 1 mg/L, there is 93% removal. Direct and Contact Filtration: Here flocculation is not a concern, as the aim is to apply small pin-sized floes to the top of sand filters, with the omission of a settling stage. If metal salts are used as coagulants, the dose is lower than in the conventional treatment described in the preceding section, to minimize the level of metal hydroxide precipitation and thus minimize the load on the filters. Cationic polyelectrolytes have a distinct advantage over metal salts since they neutralize the charge on the impurities without any significant addition of extra solids, thus extending filter runs and minimizing the production of sludge. High CD polymers perform best (Table 1), with doses typically of 0.5 to 5 mg/L of active polymer being required for the reaction,9 as described for primary coagulants. To minimize polymer use a low alum dose can be employed first, followed by the cationic polymer in

432

L-M

anionic

Chemistry in Australia

August 1994 -

AAm/AA

charge neutralization mode, rather than it causing particle bridging to give large floes. For waters high in organics a substantial polymer dose may be needed, but this can still be attractive as compared to alum usage alone since the filter run can be more than doubled. Thus for direct filtration of a water requiring 14 mg/L of alum a head loss of 100 cm of water is obtained in 5.5 h; when 10 mg/L of cationic polymer is used, instead, the run time is 15 h, and may be extended to 24h if there is a contact stage of 18 min. 5 In all these cases it is possible to condition the media particles in the filter with a neutral or oppositely charged polymer, to ensure that small floes adhere to the media rather than pass through the filter bed. The SIROFLOC Process: In the version of this CSIRO process which is in large scale use for drinking water production in Australia and the UK, the initial contact of the primary coagulant magnetite with the raw water results in rapid adsorption of humic substances to the iron oxide surface, giving the oxide a negative charge. A cationic polymer is then used to bind free negatively charged turbidity particles to the similarly charged organics-laden magnetite. 10 A high CD, medium MW polymer is the flocculant of choice (Table 1). Dissolved Air Flotation: DAF is used after coagulation and flocculation to reduce the solids loading on the filters, with short flocculation times being used to ke~ the floe size small. Otherwise usage of polymers is much as described for coagulant aids, but the applications are more in the area of wastewater treatment. The polymers utilized are shown in Table 2. Foam Flotation: In the treatment of industrial effluents that are loaded with emulsified organic material, as occurs in wool scouring or steel milling, high rates can be achieved in a new CSIRO/BHP process by first coalescing the organics and then using induced air flotation. 11 For oil and grease emulsions no coagulant is required, the necessary effect being obtained by using a cationic polymer (Table 2), which neutralizes the negatively charged organic phase. Enhanced Primary Treatment: Chemically assisted sedimentation of sewage can provide an intermediate level of treatment, to give a partial upgrade. It cannot meet secondary biological treatment performance of 85% BOD and suspended solids (SS) removal. A recent example 12 is dosing of screened sewage with ferric chloride at 50 mg/L for 6 h, then 15 mg/L for the rest of the day, plus anionic polymer (see Table 2) at 1 mg/L. Compared to operation in the absence of chemicals, BOD removal is 36% versus 15-20%, and SS removal 55% instead of 25-40%. With alum this method produces a less dense sludge. The use of ferric ions is the subject of a demonstration plant in Sydney, whereas the lime route with cationic polymer is in large scale use in Canberra and Darwin. Sludge Thickening: Some degree of concentration is normally required to reduce transport costs; the various methods available are summarized in Table 3 for a water treatment plant sludge . Polyelectrolytes are used to give denser, more rapidly settling sludges and also a clearer supernatant, which is recyclesi.8 For sludge treatment generally, polymers of medium CD and high MW give best performance, with the charge type depending on the type of sludge, as listed in Table 2. Thus for sludge from a plant producing drinking water, where alum is the coagulant, the sludge particles generally have a positive surface charge, so an anionic polymer is appropriate. 13 The settled sludge will have a solids content

Water Chemistry Supplement

Water (Supplement)

4


Table 3: Concentration of Sludges from Water Treatment Plants 8 Sludge Condition ing Method

Concentration in (% solids)

Batch Settlement Continuous thickening w ithout polymer dosing with po lymer dosing Centrifuging Filter press ing Lagooning Drying beds

Concentration out (% solids)

0.03-0.2 0.03-0.2 0.03-0.2 1-5 1 - 10 0.03-0.2 0.03-0 .2

Introducing The SFE-400â&#x201E;˘ ... RELIABLE, PRACTICAL. ECONOMICAL. Thermal Pump

1-3

5 12 20 15 15

2-3 - 10 - 17 - 25 - 40 - 30

Liquid CO 2

of 3-4%, whereas without polymer dosing it will be 1.5-2%. However, for a sewage sludge from an activated sludge plant treating sewage the biosolids have a negative surface charge, so a cationic polymer is the better performer. For the same solids content the loading of the settler will be 22-35 kg/m2/day, much higher than in the absence of polymer, when the figure is 9-11 kg/m 2/day. An exception to this general rule occurs in the thickening of red mud in the alumina industry, where a high CD, high MW anionic polymer gives best results (Table 2).

Advantages and Disadvantages The major benefits arising from polymer use are:6 the solid-liquid separation rate is increased, filter run times are extended and there is a smaller sludge volume. As well, there is a lowered usage of other chemicals, the system is less pH dependent and a wider range of waters can be treated. Only 10% w/w of the dose of inorganic reagent is generally needed, and less dissolved salt is added. The main obstacle to their greater use is cost. The benefits must outweigh the higher operating expenses. Less crucial disadvantages are that each type of water may need its own particular polymer and feed solutions of pol ymer may biodegrade. It is vital to avo id overdosing, which may negate any improvements by redispersing the impurities. A better knowledge of mechanistic details will allow more specific interactions, stronger binding effects and lower doses of polymer. This represents a challenge for future research as there are further opportunities for polymer applications in treatment processes, based on tailored polymers and specific group interactions. In this way it will be possible to achieve increased performance or lower operating costs.

References 1.

2. 3. 4. 5. 6. 7.

E. M. Thurman, in "Organic Carcinogens in Drinking Water", ed. N. M. Ram, E. J. Calabrese and R. F. Christman, Wiley, New York, 1986, p.55. S. Boggs, D. G. Livermore and M . G. Seitz,Rev. Macromol. Chem. Phys., 1985, C25, 599. W. Stumm, "Chemistry of the Solid-Water Interface", Wiley, New York, 1992, p. 114. R. Beckett and N. P. Le, Colloids and Surfaces, 1990, 44, 35 . J. K. Edzwald, in "Organic Carcinogens in Drinking Water", ed. N. M. Ram, E. J. Calabrese and R. F. Christman, Wiley, New York, 1986, p. 199. R. M. Schlauch, in "Polyelectrolytes for Water and Wastewater Treatment", ed. W. L. K. Schwoyer, CRC Press, Boca Raton, 1981, p. 125. T. Hall and R.H. Ryde, "Water Treatment Processes and Practices", WRc, Swindon, 1992, p. II/7, 90, III/35, II/23.

Brian Bolto (FRACI) is a Chief Research Scientist at the CS I RO Divis ion of Chemicals and Po lymers. He led the Waste and Wastewater Treatment Program from its inception in 1975 until 1993, being himself active in the use of po l ymers in novel water treatment processes. Dr So ito was awarded the , RAC l 's A. J. Parker App l ied Research Medal in 1983.

Patented Thermal Pump The SFE-400 extractor contains a microprocessor-controlled thermal pump thermal pressure amplifier that heats liquid CO 2 to achieve elevated pressure, elminating the need for polymeric seals, pistons, diaphragms, or syringes that wear with use. The superi0r design of the SFE-400 extractor keeps maintenance costs and downtime to an absolute minimum.

Simplified Operation, Consistent Results High pressure liquid carbon dioxide from the Thermal Pump is forced through a sample being held at a given temperature, extracting analytes from the matrix. The CO 2 and analytes flow, regulated by the restrictor to a collection vessel containing a small amount of trapping medium . As the CO 2 encounters atmospheric pressure, it goes to the gaseous state, releasing the analytes into the collection medium.

Meeting Tomorrow's Standards Today In the near future , supercritical fluid extraction (SFE) will be required in analytical and research labs as a replacement for chlorinated solvent extraction to eliminate toxic solvents that are potentially harmful to lab personnel and the environment. The SFE-400 can affordably fulfill this requirement - today!

-g-~

SUPELCO

For further information contact: '

Sigma Aldrich Pty Ltd Unit 2/10 Anella Ave Castle Hill NSW 2154

Ph (02) 899 9977 008 800 097 Fax (02) 899 7742 008 800 096

Continued on page 435 5

(Supplement) Water

August 1994-Water Chemistry Supplement

Chemistry in Australia

43~


Distinguishing Between Human and Animal Sources offaeca/Polfuuon · R. Leeming11 A. Ba/P, N. Ashbo/t21 G. Jones3 and P. Nichols 1,

MRAc1

1

CSIRO Division of Oceanography, PO Box 1538, Hobart, Tas. 7001 AWT Science and Environment, 51 Hermitage Rd., West Ryde, NSW 2114 3 CSIRO, Division of Water Resources, PMB 3, Griffith, NSW 2680

2

Pollution from human and animal waste is a major cause of deteriorating water quality and increased nutrient loads in coastal and inland waterways . Management of this problem depends on knowing which sources of faecal matter are the cause. For example, dogs and other urban animals are suspected of being a significant source of the faecal pollution found in stormwater. A method that could distinguish between their wastes would be the first step to solving this problem. The CSIRO Division of Oceanography in Hobart and AWT Science and Environment in Sydney have embarked on a detailed investigation of chemical biomarkers that have the potential to distinguish between different sources of faecal pollution. A biomarker is an organic compound that maintains sufficient structural integrity for its source to be recognized. This means that scientists can trace many organic constituents found in the environment back to their origin. One class of biomarkers has considerable potential for tracing faecal pollution: the faecal sterols. When faecal matter is introduced to aquatic environments, faecal sterols bind strongly to particulate matter and can be traced in aquatic systems for considerable distances. Large amounts of information can be gathered from sediment and water particulate samples concerning the dispersion, assimilation and fate of source materials. Researchers have been using these techniques for over 25 years. However, because the faecal coliform test has remained as "the standard indicator of faecal pollution" in legislation and because of a reluctance to accept new methods, environmental managers have been slow to adopt biomarker techniques . The prospect that biomarker techniques can distinguish between different sources of faecal pollution gives further justification for their use in environmental testing. Microbiological methods for distinguishing between faecal sources have largely focused on ratios of enteric bacteria, such as faecal coliforms and enterococci, to identify their source. Nearly all warmblooded animals host both these bacterial types and because of variability in the measurement and survival of these organisms, any such ratios found in the field are likely to be very different from ratios measured in fresh faeces. 1•4 There is therefore a demonstrable need for a technique that can investigate the contributions of the various sources of faecal pollution entering our aquatic systems. The source-specificity of faecal sterols is caused by a combination

of three factors. Firstly, the animal's diet. Humans, dogs and sheep are (respectively) omnivorous, carnivorous and herbivorous. Each diet has a different sterol profile so the pro ortions of stern! precursors entering the digestive tract are different. Secondly, even without dietary intake, many animals can biosynthesize sterols. Thirdly, and perhaps most importantly, anaerobic bacteria in the digestive tract of some animals biohydrogenate sterols to stanols of various isomeric configurations. The combination of these three factors determines · "the stern! fingerprint". The principal human faecal stern! is coprostanol, which constitutes - 60% of the total sterols found in human faeces . Coprostanol is produced in the intestine of humans and some higher mammals by bacterial biohydrogenation of cholesterol to the 5P(H)-stanol. Its presence in water indicates faecal pollution. Coprostanol is being successfully used overseas and in Australia to trace sewage pollution.2•3•5 •6•7 The structural differences between cholesterol and three common saturated isomeric (stanol) products are shown in Figure 1. The seemingly small changes in orientation of the hydrogen atom at the carbon-5 position and the hydroxyl group at the carbon-3 position, are caused by anaerobic bacterial activity in the gut. This gives human waste a distinctive stern! profile. In humans , these bacteria preferentially biohydrogenate t.5-sterols to their corresponding 5P(H), 3P(OH)-stanols. Anaerobic bacteria in the guts of other animals either preferentially biohydrogenate t. 5-sterols io one or more corresponding stanols (Figure 1), or lack the ability to biohydrogenate t. 5 -sterols at all. The stereochemistries at positions C3 and CS in the stanol are the same whether the precursor,. is cholesterol or sterols common in plants such as 24-ethylcholesterol and stigmasterol (24-ethylcholesta5,22E-dien-3P-ol).

Distinguishing Faecal Pollution in the Environment When faecal matter is discharged or washed into aquatic systems, the sterol fingerprint of the source animal is diluted and mixed with the sterol profile of autochthonous algae, detritus and other material. Despite this, the biomarkers of faecal pollution are still distinguishable from the other sterols. sp-stanols such as coprostanol do not occur naturally in fresh or marine waters or in aerobic sediments. Only H

chol•p5 ctt, H,1 r o l CH, Ctl,

COJ)rDlllllnOI

u

M A N

C

Cholealelol

ti

hum/ ,eat

~

cholesterol

D 0 G

CH,

5P·c7:proslanol ctt, Clj, CH, C

CHj

-~c1ttfJ~) H

H~

SP -eplcopro,tanol

6u ·choleslanol

H

68

Figure 1: Products of microbial reduction of cholesterol. 5aCholestane the thermodynamically most stable isomer, commonly occurs in pristine sedimentary environments .. Chemistry in Australia

/

No5o-

-

c,{c",

H

434

-

CH, CH,-~

August 1994 -

60

\ 62

68

70

72

Figure 2: GC-F/D chromatograms of sterols in human (upper trace) and dog (lower trace) faeces.

Water Chemistry Supplement

Water (Supplement)

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Control H with Carbon Dioxide • No Dangerous Acids - No Acid Fumes • Safer for Both Bathers, Employees and Equipment . . . Reduced Corrosion • Improves pH Stability . . . Raises Total Alkalinity • Simple to Install aild Operate • Safer Handling Due to High Capacity of Bulk CO 2 System • Uninterrupted CO 2 Supply Produces Exceptional Water Clarity

CARBON DIOXIDE: A SAFE AND CONVENIENT WAY TO CONTROL THE pH IN YOUR WATER CO, ... The Safe, Natural Alternative to Acid ... generates a natural bicarbonate buffer that makes the water more stable. CO, makes water safe for bathers, less damaging to equipment, and eliminates the danger involved with the storage and handling of acids as well. The aquatic industry is seeing a rapidly accelerating trend towards the use of CO, as a cost-effective replacement for muriatic or dry acid. Many aquatic industries benefit from the use of CO, . . . public and private pools, theme parks, water and waste treatment facilities, and spas. To thi s group, maintaining water beauty can be equally as important as maintaining safe pH levels. The Liquidator TCM Bulk CO, System is the safest and most convenient way to use CO,. And it is the most reliable source of CO, to connect your automated water controller. The pH level is maintained ... consistently, automatically and continuously.

TAYLOR-WHARTON (AUSTRALIA) PTY. LTD. Unit 1, 882 Leslie Drive, Albury, N.S.W. 2640, Australia Telephone (060) 40 2533 Fax (060) 40 2510 anaerobic bacteria appear to be capab le of biohydrogenating cholesterol to the 5~ isomer coprostanol and such bacteria cannot exist in waters that are aerobic. The naturall y occurring C 27 stanol in pristine environments is the Sa isomer, 5a-cholestanol, which is thermodynam ically more stable than coprostanol. Small amounts of SB-stanols can be fo und in anaerob ic sediments not contaminated by faeca l pollution,9 but th eir relative contribution to the total sterol profile is generall y less than 1-2% of the total sterols. Coprostanol constitutes -60% of the total sterols in human faeces (Figure 2). Some other warm-blooded animals, such as pigs and cats, have some coprostanol in their faeces, but both the re lative and abso lut e amo unt s are very much less than in hum an faeces. Furthermore, we have found th at dogs and many of the ubiquitous urban birds (Figure 2), such as seagulls, have no coprostanol in their faeces. Therefore, the prese nce of coprostanol in water can, under most circumstances, be co nsidered a reliable indication of human faecal pollution. At present it is possible to estimate the relative contributions of faecal pollution of herbivorous an imals (e.g. cows and sheep) and humans; 24-ethyl-coprostanol and 24-ethyl-epicoprostanol biomarkers are found in herbivore faeces in very much higher amounts than in human faeces. To accurately qu antify the contribution of sources other than human efflu ent, biomarkers unique to other animals or groups of animals also need to be identified.

Cone/ usions The source-specificity of faecal sterol biomarkers is du e to th e combination of an animal's sterol intake, its metabolic production of sterols and the gut flora resident in its digestive tract. The "sterol fingerprints" of many anima ls faeces are th erefo re likely to be distinctive enou gh to be of di agnostic v alu e in environmental inv est igation s. Th e ab ility of high reso lution capillary gas chromatography to separate unusual and trace components has further increased the possibilities of chemically distinguishing animal faeces. Research in this area is continuing with an extended range of animals and an investigation of other potential faecal biomarkers as well as classical microbiological techniques, as mea ns of distinguishing sources of faeca l pollution. We are also examining th e fate and 7

(Supplement) Water

August 1994 -

degradation rate of faecal sterols, their distribution in the water column and sediments off Sydney, in Port Phillip Bay and the Derwent Estuary, and their relationship to existing faeca l indicators.

Acknowledgements

This work was a collaborative proj ect between CSIRO Division of Oceanography and AWT-Science and Environment. We would like to th ank Sara Nespolo for her assistance in the laboratory and Dr John Volkman for his input and valuable discussions . 1. 2. 3. 4. 5. 6. 7. 8.

D. Kay and A. MacDonald, Water Res., 1980, 14,305. J. Laureillard and A. Saliot, Mar. Chem, 1993, 43,247. L.A. LeBlanc, J. S. Lat imer, J. T. Ellis and J. G. Quinn,Estuarine, Coast Shelf Sci., 1992, 34, 439-458. G. McFetters, J. S. Kippin and M. W. LeChevallier, Appl. Environ. Microbiol, 1986, 51, 1. P. D. Nicholls, R. Leeming and G. Cressswell, Water, 1992, 19, 32. M. Nishimura, Geochim et Cosmochim, Acta, 1982, 46,423. M. R. Sherwin, E. S. Van Vleet, V. U. Fossato and F. Dolci, Ma ,: Poll Bull, 1993, 26, 501. I. M. Venkatesan and I. R. Kaplan,Environ, Sci. Technol., 1990, 24,208.

Polymeric Flocculants in Water Purification Continued from page 433 J. K. Edzwald, J. D. Haff and J. W. Boak, J. Env. Eng. Divn. , 1977, 103, 989. 9. J. K. Edzwald, "Proc. Flocculation, Sedimentation and Consolidation Conf.," ed. B. M. Moudgil and P. Somasondaran, AIChE, Washington, 1986, p. 171. 10. N. J. Anderson, N. V. Blesing, B. A. Bolto and M. B. Jackson, Reactive Polym ers, 1987, 7, 47. 11 . J.P. Beeby, D.R. Dixon, S. R. Gray and J.B. Stnitham, Proc. 15th Fed. Convention, A WWA, Gold Coast, 1993, p. 548. 12. J. J. Chack, V. Rubino, S. McFarland, P. J. Krasnoff and J. Liubicich, Wa ter Env. & Tech., 1994, 6, 49. 13. W. L. K. Schwoyer, in "Polye lectrolytes for Water and Wastewater Treatment", ed. W. L. K. Schwoyer, CRC Press, Boca Raton, 1981, pp. 139, 159.

8.

Water Chemistry Supplement

Chemistry in Australia

435


Photocatalytic Oxidation for TOC Analysis Peter A. Bennett and Jeffrey C. Richards,

MRACJ

SGE Scientific Pty. Ltd., 7 Argent Place, Ringwood 3134 This article describes a simple instrument developed in Australia for Total Organic Carbon (TOC) analys is. Apart from its va lu e in monitoring the quality of water in various industrial, pharmaceutical and beverage production processes, the immediate measurement of TOC is generally gaining acceptance over the 5 day Biological Oxygen Demand (BOD) and the 2 hour Chemical Oxygen Demand (COD) tests which are commonly required by regulatory bodies on waste water discharge. Beca use all three tests are quite different, an absolute relationship between each does not generall y exist. In individual processes or streams a degree of correlation is established for each and allows the use ofTOC analysis as a virtually immediate indicator of the condition of the water. In these situations, TOC analysis is allowing process engineers to make timely decisions about the withholding or treatment of water with dramatic economic benefits.

Photocatalytic Oxidation Recently, photocatalytic oxidat ion (PCO) has been developed as an effective and environmentall y benign approach to waste water remediation using natural sunlight. Several companies now provide commercial processes fo r waste treatment using titanium dioxide based PCO technology. Titanium dioxide is a semiconductor where electron transitions from the valence band to the conduction band result from the absorption of light at wavelengths in the near UV, below 400 nm . Light energy is naturally available from sunlight in this region and is a component used in photosynthesis for plant growth. In the waste treatment process, titanium dioxide is maintained in suspension in a treatment pond where the action of sunlight causes the semiconductor to generate positive holes which interact at the surface to produce hydroxyl radicals. These act as a strong oxidizing agent on natural and sy nthetic organics in the water. Aeration provides the supply of oxygen for the oxidation process and the titanium dioxide remains unchanged as a catalyst for continued activity. The PCO process simply accelerates the photodegradation processes that occur naturally in waterways. Over recent years, the process of PCO and the effectiveness of its action on a wide variety of organic compounds have been studied in a number of research institutes . Dr Ralph Matthews and his research group at CSIRO 's Centre for Advanced Analytical Chemistry in Lucas

Heights 1•3 systematically exposed various compounds to controlled levels of artificial sunli ght from simple fluorescent "black- lights" normally used to promote growth of indoor plants. The oxidation process on each organic compound was measured by monitoring the carbon dioxide evolved from the process in a closed loop system by bubbling the gas through a conductivity cell containing pure water. The effectiveness of titanium dioxide catalyzed PCO is dramatic. All organics rapidly decay to carbon dioxide and inorganic molecules, even 2,4,6-trichlorophenol. The observ.ation that this apparatus was essentiall y a tota l organic carbon analyzer did not escape Matthews 1 and consequently patents were obtained. 2•3 Apart from its well demonstrated catalytic effectiveness, the use of titanium dioxide as a catalyst is particularly attractive as it is essentiall y innocuous compared to other oxidizing agents (persulfate) used in conventional wet-oxidation TOC analyzers. Not only is the operator hazard removed, but also waste disposal concerns are entirely eliminated. Consequently, an instrument based on this technology possesses the enviable qu alities of being both "safe" and "clean".

A New TOC Analyzer Coll aboration between CSIRO and SGE International led to the development of a small and inexpensive instrument. The SGE ANATOC * Total Organic Carbon Analyzer (Figure 1) further enhances the safety aspects of operation by eliminating the need for cylinders of compressed gases. The simplicity of this concept and the low power requirements, leads to a further benefit in terms of compact size and mobility allowing rapid relocation to critical sampling points, and hence timely results of maximum benefit can be obtained. The instrument includes a closed system containing air and catalyst solution (Figure 2). A peristaltic pump 'circulates the solution and entrained air around the liquid loop path which includes two glass coils surrounding the UV light sources. Since the PCO process occurs at ne ar UV wavelengths (300.,.400 nm ), borosilicate g lass and inexpensive, long lived "black-lights" can be used in the construction of the reaction chamber. The entrained air ensures agitation of th e sample and catalytic suspension and provides an excess of oxygen to support the oxidation process. Oxidation is carried out by illumination of the sample in the presence of 0.2% w/v titanium dioxide catalyst in water adjusted to pH 3.5. REACTION COILS

CONDUCTIVITY CELL

GAS PUMP

Figure 1: SGE ANATOC* Total Organic Carbon Analyser. • ANATOC is a trademark of SGE International Pty. Ltd.

436

Chemistry in Australia

August 1994 -

~

LIOUID LOOP · SAMPLE + CATALYST • AIR • EVOLVED CO,

=::::>

GAS LOOP · AIA + EVOLVED CO,

Figure 2: Simplified flow diagram indicating separate gas and liquid paths in a closed system. Water Chemistry Supplement

Water (Supplement)

8


The carbon dioxide generated by the degradation of organic compounds is transferred from the reaction loop to the gas detection loop at the gas-liquid separator. The carbon dioxide enriched gas stream then passes th rough to a conductiyity cell, where it dissolves, forming carbonic acid. An increase in the co nductivity of the high purity water in the cell is registered. After a few minutes of circulation and photocatalytic oxidation, the entire closed loop system reaches equilibrium where: (i) all organic carbon present at background level has been oxidized, (ii) balance has been established between the dissolved and gaseous phase of CO 2 and (iii) the physical transfer of the CO 2 enriched air between the liquid and gas loops has been completed.

Sample Analysis/Introduction Water samples are typically prepared by acidification and sparging with air to remove inorganic carbonate. The instrument convenientl y provides a suppl y of air for this purpose. The sample (from 10 µL to 10 mL) is introduced into the liquid loop via a septum in the gasliquid separator. T he sample mixes with the catalyst in suspension as it is recirculated several times through the liquid loop by the action of the peristaltic pump . The pump also draws in air from the gaseous loop which creates bubbles in the liquid to provide an excess of oxygen to support the oxidation process in the glass coils surround ing the UV light sources. By continuing circulation, the sample is completely oxidized to carbon dioxide. Within a few minutes, the conductivity stabilizes, signifying complete oxidation and equilibrium of the closed system at its new carbon di ox ide level. By relat ing the carbon equivalent of the conductivity at completion with that of the initial (baseline) conductivity, the dissolved organic carbon content of the sample is determined. The carbon dioxide accumulated in the cell (and the closed system) is then removed by ventilating the system w ith filtered amb ient air to re-establish a baseline level of carbon dioxide in the liquid and gas loops.

been found to yield to the powerful PCO process. The only differenc between an easily oxidized material (~uch as a sugar) and an intractab: compound is the speed of oxidation. Even so, the differe nce is sue that the slowest ana lysis is only twice as lengthy as the sim ples Because the instrument uses " end-point detection" to determine whe oxidation is compl ete, the co nsequence of a va riation in sampl compositi on is simply a change in the analysis duration, not a loss c accuracy in the determination.

Range, Precision and Detection Limits Since the carbon in an inj ected sample is converted to carbon dioxid and collected in a conductivity cell of fixed volume, th e instrument i essentially responding to abso lute mass of carbon. By reducing c increasing the sample injection volume, higher or lower concentratio levels can be accommodated. When hi gh levels of organics ar encountered in samples, the instrumental carbon loading is simpl reduced by decreasing the inj ected volume. For typical level encountered in drinking water (2 - 10 µgCmL- 1) injections of 1 ml are usual. The calibrat ion process covers the range to 100 µgC absolute. Bei precision may be expected in the range 20 - 80 µgC where it is bette than 2% RSD. The maximum injection volume is 10 mL, which would therefor provide the best ava ilable sensitivity for low levels of organic. Th Lower Limit of Detection is 0.05 µgCmL· 1 (50 ppb) where the signa is 3.3 times the reproducibility of determinations at or near the blan: level (Figure 4) . ID

·~I

BLANK D

BLANK+ SOppo

·~ •»

~

·~

One Step Calibration

~

~

In ANATOC, calibration is a single step process where the response of the conductivity cell is calibrated against the oxidation of a known standard. The conductivity signal has been found to follow a simple mathematical relationship with carbon content. Consequently a software algorithm is used which allows accurate and linear calibration to be achieved over a wide dynamic range using a single standard. While a number of standard materials may be used, benzoic acid has been recommended since it is safe and readily available. Most importantly, it is stable in both the crystalline form and as a prepared aqueous standard. A single injection of 0.5 mL of 200µ gCmL- 1 in the form of benzoic acid provides an accurate measure of the instrumental response over a wide working range. The effectiv eness of this calibration is demonstrated (Figure 3) where a number of measurements both inside and beyond the calibrated range exhibited a regression coefficient of 0.9998 . The entire single-inj ection calib ration process is completed within 15 minutes. Calibration is typically performed every four hours.

Oxidation of Various Organics The breakdown of various organic compounds has been extensively reported in the literature. 4•5 All compounds studied, including persistent pesticides and traditionall y difficult materials such as humic acids have

~

i

I

I

Figure 4: Alternate determinlt'tions of blank alone (approx. 100 ppb) and blank with 50ppb added, illustrate a Lower Limit of D etection o_ 50 ppb where 99% of the tests will produce a detectable difference i, signal.

Conclusion

The use of titanium dioxide as a photocatalyst for the oxidat ion o organic compounds has permitted the design of a simplified tota organic carbon analyser which achieves a breakthrough in terms o safety for the operator, cleanliness in waste disposal and mobilit: because of the abse nce of a compressed gas cylinder. The PCC technique has been fou nd to be effective with even the most intractabl< organics. The ANATOC instrum ent is proving to be invaluable fo sample screening fo r the presence of organic contaminants and fo1 monitoring process and waste streams in real time for informed decisior making in the plant. It is also of value in replacing or minimizin! BOD or COD ana lys is.

References l. R. W. Matthews, M . Abdullah and G. K.-C. Low .Anal. Chim. Acta, 1990, 233, 171; Chem. Aust., 1990, 57, 85. 2. R. W. Matthews, US Patent, 5,244,811 3. R. W. Matthews, Eur. Patent , 346384 4. R. W. Matthews, Water Res., 1990, 20, 569. 5. R. W. Matthews,]. Cata/., 1990, 111,264.

Peter Bennett, B.Sc. , FRM IT (Management) is Business Development Manager for SGE. 1 Peter has a wide experience in the development of instrumentation for chem ica l analysis. INJECTED (ugC/mL)

Figure 3: Single p oint calibration at 150 µgCmL -1 exhibits linearity from 0 - 200 µgCmL'1. 9

(Supplement) Water

August 1994 -

Jeff Richards, Dip. App. Sci. is an experienced analytical chemist and is Sales Manager for SGE and Product Manager for TOC analysers in Australia/NZ.

Water Chemistry Supplement

Chemistry in Australia

437


Flow-Proportional Sampling of Sewage N. H. Pilkington,

MRACJ

and}. S. Bridger

CS/ RO, Division of Chemicals and Polymers, Clayton, Vic. 3168 This article describes a flow-proprtional sampling system developed to fac ilitate the operation of a sewage treatment pilot plant. The principles could be applied to other processes. Our system overcomes problems of sample instability due to biological reactions, and uses computer-controlled pumps to obtain flow-proportional samples which more adequately represent the mass flux (flow x concentration) in th e main sewer.

Flow-Proportional Sampling To develop new treatment processes, or adapt existing processes to new situat ions, it is necessary to sample the total system. Sampling at a fixed flow rate is satisfactory in the production of potable water, since the qu ality of the incoming raw water from a reservoir is more or less constant and the flow varies only slowly, or is either on or off. However in a sewage system, both the flow rate and concentrations of components vary continuously. Unless there is a long and large trunk sewer, or large holding tanks to equalize the load, the operator has no option but to accept the varying flow. An increase in flow rate has two effects on effluent quality: it increases the load and decreases the residence time in the treatment plant. Thus th e error in operating a pilot plant with fixed flow sampling can be large. For example, Figure 1 shows typical diurnal variations in a domestic sewer. The concentration and mass flux vary by a factors of 3.6 and 43 respectively. A similar consideration also applies to the collection of composite samples for chemical analysis. Unless the sampling is flow proportional, the composite sample's composition will not represent the integrated mass flux. Until quite recently, constant flow was the only mode in which most commercial automatic samplers could be operated.

Difficulties in Sampling Sewage The raw sewage fed to the pilot plant must represent that in the main sewer, but additional difficulties arise in sampling sewage because of the very nature of its composition. Solids: Design of sampling systems for sewage must allow for the presence of large and variable amounts of solids. Blockages may occur and the solids may adsorb species being analyzed. After primary sedimentation, the solids tend to be more colloidal and easier to sample. Precautions must be taken to ensure that screens do not become blocked and that the sampling lines are able to carry the solids without depositing those solids which pass any input screen. As the sampling lines become smaller, it may be necessary to be partially selective for the liquid phase. One technique we have used is to place T-pieces at the top of sampling lines so that the larger particles can pass by without being collected. Bell-shaped intakes assist by reducing the flow velocity at the point of sample collection, but care must be taken so that retention time in the system is not unduly affected. Sample instability: Sewage also carries an active bacterial population th at is beneficial to the treatment process, but results in sample

instability. Raw sewage, in particular, can quickly become anaerobic and fe rment, removing some compounds whilst liberating others. Samples collected at other stages of a treatment process may contain aerobic microorganisms which consume compounds of interest. The presence of microorganisms can also lead to the deposition and build up of biofilms in a sampling system . These may further enhance sample degradation. The concentration of volatile fatty acids (VFA) such as acetic, propionic and butyr ic acids, are both substrates for some microorganisms and metabolic by-products of others. In addition, th eir volatility can also result in losses. We have found that VFAs in unpreserved samples of primary fermenter tank effluent can fall from 50 to 2 mg/L within the two hours after sampling. Whether the error due to sample instability is significant depends on the relative volumes of the sampling lines and the size of the sample collected, the reactivity of the sample and also the frequency of sampling, which affects the static holding time in the lines . Such instability is a particular problem with many commercially available samplers .

The CS/RO System Pilot Plant: CSIRO operates a field station at Lower Plenty, a suburb of Melbourne , where various biological and physico-chemical processes are being investigated for the treatment of sewage and surface waters. One pilot plant investigates the removal of nutrients, phosphate and ammonia. Sampling was necessary for two purposes: abstraction of a relatively small flow of 5 kL/day from a mains sewer with an average flow of ca. 10 ML/day;, and sampling of the pilot plant for process monitoring. Sampling Strategy: An IBM-compatible computer (an XT is sufficient) was programmed to coq.trol the flow rate of sampling pumps to be proportional to the predetermined diurnal flow. Such a simple, modular-program system is effective because of the characteristics of domestic sewerage systems . Typically, both the volumetric flow and the concentrations are low overnight and peak in the morning as the population goes about their normal daily ablutions. There may also be superimposed weekly patterns, such as the additional water usage and use of detergents on Monday, and less flow at weekends in industrial areas. An additional complication is increased flow rate during periods of heavy rain because of infiltration and illegal storm water connections. However, it is mainly the amplitude of the concentration that is affected, while the ratios of the relative flows at the various times of day remains fairly constant each day. Thus, it is possible to design a simple computer program to " read" the flow from a look-up table, and adjust an output accordingly. Computer Program: The logic flow -diagram for our program, RUNPUMPS, is shown in Figure 2. It was programmed in "Microsoft Quick C" and compiled before running. The voltage output values in the look-up table were determined using the measured relative hourly Figure 2. Logic flow -diagram of RUNPUMPS.

Pulse â&#x20AC;˘ â&#x20AC;˘d t h "odvlotâ&#x20AC;˘ Voltooe r,odvle

04 00

0800

1200

1600

2000

nme of day (hrs)

Figure 1. Diurnal variation in Total Phosphate-?, Flow and Phosphate-? Mass Flux in raw sewage at Lower Plenty. 438

Chemistry in Australia

August 1994 -

Water Chemistry Supplement

Water (Supplement)

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To So.Mpl e PlM"'lps

D!ur no.l flo w to Pilot Plo.nt (3L/l"lln) -+ SubMer slble Puf'lp (60L/f'lln )

...__.,~ LAil.

Ro.w Sewo.ge SUMP

11 P;tot Pto. nt

== ~wm~f'.~~~ -_,.~._~_.~. _,· MAIN sEIIER

_.

Figure 3. Sampling system for raw sewage feed to a nutrient removal pilot plant.

flows , scaled down to the desired average flow rate, and a measured cal ib ration curve (flow vs . voltage (or frequency) input) of the characteristics of the particular pump used for each sampling application . This program is readi ly portable to other applications simpl y by incorporating an appropriate look-up table. For our application, an hourly look-up of the flow rate provided sufficient accuracy. If necessary, the look-up table can be improved by increasing the frequency of points (e.g. to 61hr) and by extending the length of the table to cover a longer flow period (e.g to weekly with lower flows at weekends and increased flows on Monday). In principle, it is possible to further develop the program to use feed back from an in-line flow measurement device. In practice, some modification was found necessary for low overnight flows. The program 's progress and performance may be monitored onscreen. In case it is necessary or desirab le to change operating parameters such as the output voltage or screen format, a module to monitor keyboard interrupts has also been included in the program . The individual modules also incorporate relevant error checking loops.

Hardware: : IBM XT-compatible clone. Computer :ADALAB DIA Board : Gilson MiniPuls 3. Analytical Sampling Pump : ASEA Micro Drive Mark II . Frequency Converter : Mono CP 800. Pilot Plant Feed Pump Sampling system: Raw sewage is pumped from the main sewer through 100 mm i.d. pipe using a submersible pump-macerator (Figure 3). The power of the pump is sufficient to break up all but the most recalcitrant solids, ensuring that the raw sewage feed satisfactorily represents the main sewer flow. The macerated sewage runs continuously through a sump and the excess returns to the main sewer. The feed to the pilot plant is then drawn from the sump on a flow proportional basis. As described above, a voltage output generated from the computer look-up table is used to operate a frequency converter wh ich, in turn, operates the feed pump. The frequency converter (7.5 Hz outputN input), and feed pump have been matched to provide the desired average flow rate of 3 Llmin to the pilot plant. At the low overnight flow rates required, the output frequency is so small that the pump stalls. To overcome this problem, the program was modified so when the output voltage is equivalent to a frequency which is below the stalling frequency (1 .25 V or 10 Hz, in our case), the pump is operated only intermittently, but at a frequency above the stalling point. The on- and off-times are determined so that the average net time-on corresponds with the desired average flow rate. We have termed this mode of operation "Pulse Width Mode" . Each hour is divided into 10 min. periods, and the time-on period is set as an integral number of minutes. Thus the minimum operating time of the pump is 10%. The look-up frequency remains at hourly intervals, but could be adj usted, if necessary, by developing a new table. Composite Analytical Samples: The analogue output from the DIA converter is suitable for directly controlling the voltage-controlled peristaltic sampling pumps. By appropriate selection of maximum pump r.p.m. and tubing i.d., the system has been designed to collect ca . 1 litre composite samples over a 24 hr period. The analytical data from these samples is subsequently used for process monitoring, control and performance assessment. Three points for composite sampling have been installed on the pilot plant: raw sewage (raw feed), primary fermenter effluent (BNR plant feed) and final effluent. In each case, the samples are taken as sub-samples from a continuously rapidly pumped sampling line. The rapid flow .through the sampling 11

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Pilot Plant

t

":··1' ~ RA\J SE\JAGE SUMP

PRI MARY FERMENTER

NUTRIE~T REMOVAL PIU)T PLANT

FINAL CLARIFIER

Figure 4. Ana lytica I sampling system for collecting flow proportional composite samples from a nutrient removal pilot plant. lines se rv es two purposes: fir st, the scouring effect preve nts the potenti al deposition and build-up of biofilms which might contribute to substrate removal from the sampl e, and second, the hydraulic retention tim e is minimized , thereby decreasing both auto - and biofilm-induced decomposition reactions. The two samples which must be specially prese rved are take n from a point as close as practicable to the refrigerator, with the delivery line from the pump passing through the refrigerator wall. Thus, retention times within the syst em are min im al ( < 30 s total) , and al so the flows are continuous. Sample decomposition in the sampling lines is minimal, and, when required, acid may be added to the collection vessels prior to use to further ensure sample preservation (Figure 4).

Sample preservation: To overcome problems of sample instability due to biological reactions, raw sewage and fermenter effluent samples for ana lytical purposes were collected into a refrigerator at <4 °C. Additionally, when sampling for VFA analysis, 0.5 mL of 98% H 2SO 4 per li tre of sample to be collected was added as a preservative to the containers before sampling. Pilot plant final effluent samples were stable for at least 48 hr, so were collected at ambient temperature, and then refrigerated or frozen until required.

.

Conclusion A computer-based flow-proportional sampling system based on the pre-determined diurnal flow pattern has been used to sample domestic sewage and a pilot scale treatment plant so that the mass flux of the pollutants is taken into account. The signal generated is used to control a system for collecting composite samples for chemical analysis and also used to control the feed pump to the pilot plant. The design of the analytical sampling system also minimizes the potential for sample decomposition caused by inherent chemical or physical instability or by biofilm growth . The computer program could be improved by using a look-up table with smaller time increments, or, even better, by using feed back from on-line flow measurement, but that degree of sophistication was not necessary in this application .

Acknowledgments The authors are grateful for the contribution of Mr P.J. Fitzgibbon to the writing of the computer program, to Ms M.A. Kelly who carried out the phosphate analyses, and to Messrs. G. Lester and M. Robinson for operation and maintenance of the pilot plant. The biological nutrient remova l pilot plant work was partially funded by the A ustralian Water Research Association Council (Grant 88/10). Norman Pilkington (MRACI) in the CSIRO Division of Chem icals and Polymers is currently a Principal Research Scientist whose research in te rests include the identification and analysis of disinfection by-products and the use of chemica l biomarkers for studying the active microbiological populations fn water treatment processes. John Bridger is a Senior Research Scientist with CS IRO Division of Chemicals and Polymers. He is currently Officer-in-Charge of the Lower Plenty Experimental Stat ion and is actively in volved in biologica l nutrient removal from sewerage (BNR), and in process instrumentation and control.

Water Chemistry Supplement

Chemistry in Australia

439


Treatment of Liquid Cyanide Wastes Zoran Slavnic Warman International Ltd., PO Box 51, Artarmon, NSW 2064 Cyanide wastes are defined by many waste management authorities to include free and complex cyanides, cyanogens, cyanide salts and organonitriles. As cyanides are highly toxic and fast acting poisons, Australian waste management and environmental authorities have classified cyanide wastes as haza rdous and restrictions on them have become increasingly stringent. Due to potential environmental impacts, such wastes must be treated before discharge into the environment. This article provides a review of liquid cyanide wastes only, and the treatment/ destruction technologies in current use. Concentrations of 0.1 mg/L of hydrogen cyanide kill sensitive fish species, 1 and for a human adult the lethal dose can be as low as 50 mg. 2The toxicity of cyanide waste solutions to aquatic life is directly related to their abilities to produce free cyanide ion or form hydrogen cyanide, and thus sodium, potass ium and calcium cyanide salts are the most toxic. Complex cyanide salts release less cyanide and are less toxic. Australian waste management and environmental authorities do not allow wastes with cyanide concentration exceeding 0.05 mg/L to be discharged into the waters class P and C (protected waters and controlled waters). 4 Cyanide wastes of concentration not higher than 1.0 mg/L may be discharged into sewers. 5 Hydrogen cyanide and sodium cyanide, are the two main cyanide compounds in use by industry. Liquid cyanide wastes are mainly generated by the following industries: Chemical and petrochemical industry: Most of the cyanide generated by these industries comes from production of acrylonitrile and from thermal and catalytic cracking of petroleum. Electroplating or metal surface treatment: Sodium cyanide is used in electroplating and cleaning of cadmium, chromium, nickel, zinc and copper and its alloys. Thus, sludges from rinse baths, residues from in-line filters, and spent baths, rich in cyanides, are generated. Concentration of cyanides in rinses are well under 1,000 mg/L, but spent baths may range to 100,000 mg/L. 6 Mining industry: Cyanides are used in ore extraction and recovery of gold and silver. Wastewaters and sludges from these processes contain high concentration of free and complex cyanides. Miscellaneous industries: Bleaches, used in photographic film processing solutions, contain up to 100,000 mg/L of ferricyanide; 6 coke furnaces by product waste streams contain several hundreds mg/L of cyanides and are amongst the most difficult to treat, due to the presence of high concentration of other pollutants (COD, ammonia, phenol, thiocyanate).

Treatmen.,. ;Destruction U' II' Although recognizing the importance of waste minimization techniques and recovery processes, the following summarizes only the treatment/destruction technologies of liquid cyanide wastes. Physical removal processes: The technologies for physical removal of cyanide include membrane separation and ion exchange. Both are mainly used for the treatment of electroplating rinse waters. Ultrafiltration is the most proven membrane process in the treatment of solutions containing metal ions and cyanide. It utilizes thin porous membranes which are selectively permeable to one or more ions. Ultrafiltration systems typically operate at pressures ranging from 65 to 650 kPa and are considered suitable for separation of molecules ranging from 1,000 to 1,000,000 in molecular weight. The sizes of particle retained are in the order of 0.001 to 0.02 microns . Typical feed concentrations of cyanide are in the range of several hundred mg/L with effluent concentrations of 0.1 mg/L. Chemical precipitation and microfiltration are often used as a pretreatment to remove suspended solids (to prevent clogging of membrane pores) and other substances that may interfere with the separation process. In ion exchange processes, free cyanide is first reacted with ferrous sulfate at pH 8 to 9 to form ferrocyanide or ferricyanide, then filtered and contacted with an acrylic, strongly basic anion exchange resin 440

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highly selective for these cyanide complexes. 7 The resin is regenerated with aqueous sodium chloride. Apart from high operating costs, the main disadvantage of both processes is that they generate low volume but highly concentrated toxic residuals which require a secondary treatment. Chemical destruction: The following technologies are in commercial use for chemical destruction of cyanide. Oxidation by hypochlorite is widely used for cyanide destruction in wastewaters from plating operations (less than 1,000 mg/L). H2O + CN- + oc1- 7 CNCI + 2QHCNC1 + 2OH- 7 CNO- + CJ- + Hp 2CNO- + 3OCJ- + 2Hâ&#x20AC;˘ 7 2CO 2 + N 2 + H 2O + 3CJTo avoid liberating cyanogen chloride (CNCI), an extremely toxic gas, sufficient chlorine must be added. Cyanate is 1000 times less toxic than cyanide, and may be further oxidized at pH 4 to carbon dioxide and nitrogen. Alkaline chlorination with gaseous chlorine at pH 10 or higher, is also widely used for treatment of dilute cyanide waste streams (several hundred mg/L) from metal finishing and gold processing operations. Under these conditions similar reactions occur to produce carbonate and nitrogen. The presence of stable iron and nickel cyanide complexes in high concentration may result in poor removal efficiencies. Another limitation of the processes is potential generation of toxic by-products, such as cyanogen chloride gas, and formation of trihalomethanes which are suspected carcinogens. Ozonization: Ozone is used in treatment of very dilute cyanide waste streams. Because it decomposes, ozone must be manufactured on site with an electric generator. Ozone is more soluble in water than oxygen and readily oxidizes cyanide to cyanate under all pH conditions. If sufficient ozone is present the cyanate is further decomposed to carbonate and nitrogen. However, he disposal of off-gases from ozone contactors is a major problem. Ozone rapidly dissociates on heating. Consequently, the off-gases from the ozone contactors are heated up to 250 °C. Sulfur-based destruction: The most known sulfur-based technology for cyanide destruction in plating rinse and gold mining waste streams is the relatively new INCO process (a proprietary process of Inca Metals Company). The process uses a mixture of sulfur dioxide and air at controlled pH (9 to 10) in the presence of soluble copper (CuSO 4) as a catalyst. The overall reaction is as follows: CN- + so2 + 0 2 + Hp 7 CNQ- + H2so. This process removes cyanides from dilute and concentrated aqueous waste streams (containing several thousand mg/L of cyanide) down to less than 1 mg/L. Metals and iron cyanide are also removed from solution, by precipitation, as hydroxides. The sludge is toxic. Oxidation by hydrogen peroxide: Hydrogen peroxide, a relatively strong oxidizing agent, is used to treat dilute cyanide waste streams. Cyanate is formed which hydrolyses to carbonate and ammonia. The reaction is generally performed at pH 10 to 11 in the presence of a metal catalyst, typically soluble copper salts (CuSO 4) but nickel and aluminium salts are also often used. Biodegradation: Microbiological degradation of low concentration cyanide streams is a feasible alternative to conventional chemical processes. Using an activated sludge process simple cyanides (cyanide, cyanate and thiocyanate) are oxidized by aerobic autotrophic microorganisms into carbon dioxide, ammonia and also sulfate (in the case of thiocyanate). Most conventional biological systems, even when acclimatized, are not able to degrade cyanide complexes or high concentrations of simple cyanide. In addition, high concentrations of ammonia, heavy metals and of a wide variety of organic compounds, such as phenols, often cause serious upsets in biological systems. For these systems total cyanide concentration should be kept at less than 10 mg/L. However, high rate systems using pure oxygen are capable of treating several times higher concentrations. In order to

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EPA Methods 418.1, 413.2 -

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Buck Scientific keep cyanide concentration within, by microorganisms, acceptable limits, dilution of high concentration streams or chemical destruction of cyanide is required prior to the biological step. This is of paramount importance if nitrification is included, which is the most sensitive part of the process. The chemical destruction should be accomplished by a biodegradable agent, e.g. formaldehyde. Since the end products of complete biodegradation are nontoxic, biological treatment has been more frequently used in treatment of high volume but low concentrated cyanide wastes. This is particularly the case with wastewaters in coke and petrochemical industries. The problems associated with biodegradation of these wastewaters might include non-stable process due to variations in quality and quantity of pollutants in the influent, unpleasant odour if anaerobic conditions occur and foam formation . Extended aeration and the use of pure oxygen can help to eliminate these problems. Electrolytic destruction: Electrolytic processes are generally used at the source of waste generation. Plating solutions and rinse waters containing high concentration of cyanide (up to 100,000 mg/L) are successfully treated by electrolysis using titanium electrodes. Cyanide is oxidized at the anode, forming cyanate as an intermediate product and carbon dioxide, nitrogen and ammonia as end products. The process is of batch type and can achieve low levels of effluent cyanide (0.1 mg/L) if sufficient treatment time is allowed. The time needed is in the order of few days up to 20 days, depending on the initial Continued on page 444

Zoran Slavnic is a Chartered Profess ional Eng ineer, a Corporate Member of the Institution of Engineers of Australia, with a degree in Mechanical Eng ineering and a Masters Degree in Environmental Engineering. He is employed by Warman International Limited, with project management/engineering duties, on projects for potab le water and municipal and industr ial waste -water treatment and he possesses an extensive experience (over 12 years). 13

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Disinfection and Water Treatment: Formation of Chemical By-products Brenton C. Nicholson,

MRAc1

Australian Centre for Water Quality Research/State Water Laboratory, Engineering and Water Supply Dept., Private Mail Bag, Salisbury, S.A. 5108 Disinfection is undoubtedly the most important of the water treatment processes and in many instances is the only treatment app lied . Nonetheless it is beset with a potentially serious disadvantage, the forma tion of chemical disinfection by-products (DBPs). The DBPs of most concern are the products of the reaction of chlorine with the naturally occurring organic material in water, or in the case of chlorine dioxide the concern is with chlorite and chlorate, transformation products of the disinfectant itself. This concern has directed attention at alternative disinfectants which are also not without disadvantages . This article outlines their chemistry and discusses the implications of the recent draft guidelines.

Chlorination By-Products Chlorine has remained the disinfectant of choice for most water authorities si nce the early 1900s because it is highl y effective and relatively cheap. In 1974 potentially harmful DBPs , the trihalomethanes (THMs) , were detected in drinking water. Subsequent research s howed that THMs originated from the reaction of the chlorine with naturally occurring organic matter (NOM) in water, humic and fulvic acids. The most common THMs are chloroform, bromodic hloromethane, dibrom oc hloromet hane and bromoform. Brominated THMs arise from ox idation of natural bromide by hypochlorous acid to hypobromous acid which reacts with NOM in competition with the remaining hypochlorous acid . As bromide levels increase, the distribution of THMs is shifted to the more highly brominated species . Other DBP s now known to be produced by chlorine include halogenated acet ic acids (HAAs), hal oaceton itriles, halogenated ketones, chlora l hydrate , cyanogen chloride, chloropicr in and chlorinated phenols as well as non-halogenated oxidation products such as short chain aldehydes. 1 Bromide shifts the distribution of other halogenated DBPs such as HAAs to more highly brominated species in the same way as it shi fts the distribution of THMs. Identifiable by-products, including THMs, constitute only about two thirds of the yield of halogenated material formed during chlorination (Table 1). The remaining one third has yet to be identified but is probably higher molecular weight material. Of the identified by-products THMs represent about one half of the yield with haloacetic acids comprising the major part of the remainder. Higher precursor levels, higher chlorine dose rates, longer reaction times, higher pH and higher temperatures all form more THMs. Higher THM levels also tend to be formed in more saline waters where bromide levels are higher. The hypobromous acid formed is more effect iv e at halogen s ub stitution than chlorine (chlorine acts preferentially as an oxidant). 2

Table 1: Halogenated By-products of Chlorination Class of Typical % total halogenated Compound Compound by-product yield Trihalomethanes Chloroform 35 (20 - 40) Haloacetic acids Trichloroacetic acid 30 (10 - 50) Haloacetonitriles Dichloroacetonitrile 3 (< 1 - 5) Chloral hydrate (CC l 3C(OH)) 3 (<1 - 5) Halogenated ketones 1, 1, 1-trichloracetone <1 - 1 Cyanogen chloride <1 - 3 Chloropicrin (CCl 3 NO 2) ÂŤ 1 Halogenated phenols 2,4,6-trichlorophenol <<1 "MX" <<< 1 30? Higher molecular weight material

442

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In most cases the factors described above (apart from pH 4) will affect formation of other DBPs in the same way as THM formation. However there are exceptions, e.g., pre-ozonation reduced most other DBPs except chloral hydrate and chloropicrin which increased significantly in concentration.3 Presumably precursors of the various DBP classes are different and some precursors are lowered by preozonation whilst the chloral hydrate and chloropicrin precursors must be increased. THM and hence DBP format ion can be controlled by limiting chlorine doses, adding chlorine after some precursors have been removed by clarification or filtration, using alternative pre-oxidants or using alternative disinfectants. DBPs can be removed afterwards, e.g., air stripping in the case of THMs or granular activated carbon (GAC) adsorption, but these options are expensive.

Ozonation Concern over the toxicity and possible carcinogen icity of some halogenated DBPs has resulted in more expens ive alternat ive disinfectants such as ozone finding increasing favour. These may also form DBPs, some of which have been identified, but research on their identit y and toxicology is in its infancy. Ozone has been used extensively overseas for many years as a primary disinfectant but is not used to any extent, if at all, in Australia. It is the most likely replacement for chlorine, at least for primary disinfection . Because it provides no disinfectant residual, a secondary disinfectant such as chlorine or chloramine is required to provide a disinfectant residual in the distribution system. Ozone produces a range of non-halogenated by-products (Table 2) which have not been completely characterized. Aliphatic aldehydes, mainly formaldehyde, but also higher simple aldehydes as well as glyoxal and methylglyoxal, appear to constitute a large proportion of the by-products formed. 5 More recently ketoacids such as glyoxyl ic and pyruvic acids have been identified at levels higher than those of the aldehydes. 6 Many of these compounds are readily removed in biologically active filters which is fortuitous as there are concerns that, without their removal, they may act as a food source for micro-organisms in the distribution system . This will in turn contribute to bacterial regrowth with a consequent reduction in the microbiological quality of the water. Ozone can also oxidize bromide to hypobromous acid which can produce brominated DBPs including bromoform by reaction with

Table 2: Major Non-halogenated By-products of Ozonation Formaldehyde (HCHO) MonoAcetaldehyde (C H 3 CHO) aldehydes

Di-aldehydes

Ketoacids

Water Chemistry Supplement

Propionaldehyde (Propanal) (CH 3CH 2CHO) Butanal (CH/CH) 2 CHO) Pentanal (CH/CH 2) 3 CHO) Heptanal (C H/C H) 5CHO) Glyoxal (CHO-C HO) Methylglyoxal (Pyruvald'ehyde) (CH 3COCHO) Glyoxylic acid (HCOCO 2 H) Pyruvic acid (C H 3COCO 2 H) Ketomalonic acid (HOCOCOCO2 H) Water (Supplement)

14


naturally occurring organic matter. 7 However in most cases bromoform production by this route appears to be insignificant except in more saline waters where bromide concentrations are relatively high. 3 Even then the concentrations produced are not particularly high, and are usually insignificant compared with the THM levels produced by subsequent post-chlorination. Bromate is a more recently identified by-product of concern which arises from the naturally occurring bromide in water. Bromate is likely to be regulated to a very low level and it will be important to minimize its formation as much as possible. Its formation is affected by pH (hypobromite can be oxidized by ozone to bromate but hypobromous acid cannot), alkalinity and ammonia concentrations, 7•8 which may offer some scope for its control. The presence of hydrogen peroxide as used in the PEROXONE process also enhances the formation of bromate. 8

Ozonationlch Jori nation Ozonation for primary disinfection or for pre-oxidation has the capacity to significantly reduce THM formation when followed by chlorination in a secondary disinfection step. However in some situations THM formation can actually be increased due to the formation by ozone of more reactive THM precursors from the NOM present. The main factors affecting subsequent THM formation relate to the ozone dose which will determine the degree of oxidation of THM precursors, and the degree of removal of THM precursors in treatment processes prior to chlorination. THM reductions of around 10% only appear to be achieved in practice.9 Some of the specific ozonation by-products which are removed by biological filtration, e.g., acetaldehyde and pyruvic acid, have been shown to be THM precursors and hence it is not surprising that biological filtration following ozonation has the potential for reducing DBP formation on subsequent chlorination. 10

Chloramination

,,

Chloramine, essentially monochloramine, formed from chlorine and ammonia, has been used for some time as a disinfectant although long contact times are required for adequate disinfection. It is more useful as a secondary disinfectant to provide a persistent residual following primary disinfection with chlorine or ozone. Chloramination can be extremely effective in reducing DBP formation. The extent of THM and DBP formation depends mainly on the sequence of addition of the chlorine and ammonia and the time between addition. Adding chlorine first is equivalent to chlorination with its inherent problem of DBP formation. However this sequence provides better disinfection and may be favoured in situations where raw water quality is good and DBP formation is not a problem. Minimizing the time between addition of the chlorine and addition of ammonia will obviously minimize DBP formation . The greatest reduction will occur when chlorine and ammonia are added together or if there is pre-ammoniation. DBP formation with preformed chloramine is essentially zero; however the ratio of chlorine to ammonia must be carefully controlled to avoid the presence of excess chlorine which will result in a free chlorine residual and hence DBP formation . However, concentrations of cyanogen chloride in excess of those formed by comparable chlorine doses can be generated. 1 In more saline waters monochloramine can produce iodoform in concentrations sufficiently high to impart objectionable medicinal tastes and odours to the water. 11 Iodoform formation did, however, depend on the order of chlorine and ammonia addition. Surprisingly addition of ammonia followed by chlorine was the circumstance under which iodoform was formed. DBP formation following ozonation/chloramination will depend primarily on the chloramination procedure.

Chlorine Dioxide

only the chlorine dioxide itself but also i_!s reaction products chlorite and chlorate. Expected stringent guidelin1s for these by-products wi ll limit the use of chlorine dioxide as a disinfectant or pre-oxidant, especially when considering its high cost.

DBP Guidelines and Regulations The drinking water limits set to date for DBPs apply to THMs and chloroform and have been set based on available toxicological information, although the US EPA considered whether treatment could reduce THM levels. The consideration of these non toxicological factors plus differences in interpreting and extrapolating the animal toxicity data has sometimes resulted in a wide range of limits . Limits for DBPs including THM s and chloroform have recently been reviewed or are currently being reviewed by a number of organizations. The debate will thus soon cover a much wider range of compounds than THMs alone. US EPA Regulations: THMs were originally regulated in 1979 with a maximum contaminant level (MCL) of 100 µg/L stipulated. Limits for THMs and other DBPs are currently being assessed through the " disinfectant-disinfection by-products" rule, a draft for which is expecte d shortly following "regulatory negotiation " with the stakeholders. 12 Information rece ntly to hand indicates that MCLs for THMs, HAAs and bromate of 80, 60 and 10 µg/L respectively have been agreed to. WHO Guidelines: WHO formed a Review Group to carry out the task of preparing guidelines for a number of disinfectants and DBPs, as well as reviewing the current guideline of 30 µg/L for chloroform. The resultant guidelines were published in late 1993. Canadian Guidelines: The Canadian guideline for THMs (350 µg! L) is currently being reviewed and a guideline value of 50 µg/L is likely for both THMs and chloroform. NH&MRC/ARMCANZ Guidelines: Australian drinking water guidelines (Table 3) hav e recently been released for comment following three years of review through various panels of experts under the auspices of NH&MRC and the Agricultural and Reso urce Management Council of Australia and Ne'r' Zealand (ARMCANZ). Assuming that the draft NH&MRC/ARMCANZ guidelines for DBPs are adopted, what are the implications for water authorities? For DBPS the THM guideline (200 µ g/L) is less stringent than that currently in place and will obviouscly be easier to meet. However the " limiting" DBPs will now be compounds such as chloral hydrate and the haloacetic acids, in particular DCAA, if relationships to THM or chloroform concentrations follow the trends indicated by US monitoring data. From the US data it can be est im ated that concentrations of both DCAA and TCAA are likely to be similar to chloroform concentrations in most circumstances. Thus meeting a DCAA guideline of 50 µg/L may be equivalent to meeting a chloroform limit of 50 µg/L. Similarly chloral hydrate concentrations may be up to 40% of the chloroform concentration. This too would limit the chloroform concentration to around 50 µg/L. In other words if a chloroform limit of 50 µg/L cannot now be met, the proposed guideline values for DCAA and chloral hydrate are unlikely to be met. A TCAA guideline value of 100 µg/L which may be equivalent to a chloroform limit of 100 µg/L will be much less restrictive in comparison. Other DBPs such as chloroacetic acid, chlorophenols, cyanogen chloride and formaldehyde are unlikely to be issues as guidelines are not expected to be exceeded under any disinfection regime. The philosophy behind the NH&MRC/ARMCANZ guidelines is that they will be used as the basis for establishing standards or levels of service following consultation with the community. However it is expected that health related guidelines will be "non-negotiable" and adopted without change. Strategies may be required to achieve compliance with guideline values depending on disinfection and water treatment practises .

To meet the new guidelines may involve additional and expensive Chlorine dioxide is a powerful disinfectant with an activity similar treatment technologies e.g., ozonation followed by chloramination, to chlorine but with a disinfectant capability much Jess susceptible rather than traditional chlorination, or removal of1 DBPs or precursors with activated carbon. It is not clear at this point in time whether the to pH. Chlorine dioxide does not form THMs but if it is generated from hypochlorous acid and sodium chlorite the associated free proposed guideline of 20 µg/L for bromate which is a by-product of chlorine will form THMs. Chlorine dioxide oxidizes THM precursors ozonation will limit the usefulness of ozone as a disinfectant, especially in more saline waters where bromide levels are relatively so that its use as a pre-oxidant will result in reduced THM formation if followed by chlorine. However chlorine dioxide disinfection is an high. expensive process and there is concern over the health effects of not Disinfection of drinking water is a necessary and well accepted 15 (Supplement) Water August 1994 - Water Chemistry Supplement Chemistry in Australia 443


practice for preventing the spread of seriou s and potenti all y fatal water borne diseases such as typhoid and cholera. While the benefi ts of disinfection of drinking water have been enjoyed for almost 100 years, risks resulting from by-proquct formation associated w~th this practice hav e only recentl y been recognized. The s uppl y of a microbiologically safe disinfecte d drinking water must now balance the benefits of disease co ntrol against the risks associated with potentiall y toxic DBPs . References

1.

S.W. Krasner, M.J. McGuire, J.G. Jacangelo, N.L. Patania, K.M. Reagan and E.M. Aieta, J . Am. Water Works Assoc., 1989, 81(8) , 41. 2. J.J . Rook, A.A. Gras, B.G. van der Heijden and J. de Wee,]. Environ. Sc. H ea lth , 1978, A13, 91. 3. J.G. Jacangelo, N.L. Patania, K.M. Reagan, E.M. Aieta, S.W. Krasner and M.J. McGuire, J. Am. Water Works Assoc., 1989, 81(8) , 74. 4. A.A. Stevens, L.A. Moore and R.J. Miltner, J. A m. Water Works Assoc., 1989, 81(8) , 54. 5. S.W. Krasner, M.J. Sclimenti and B.M. Coffey,]. Am. Water Works Assoc., 1993, 85(5) , 62. 6. Y. Xie and D.A. Reckhow, Ozone Sc. Engng., 1992, 14, 269. 7. W.H. Glaze, H.S. Weinberg and J.E. Cavanagh,]. Am. Water Works Assoc., 1993, 85(1) , 96. 8. S.W. Krasner, W.H . Glaze, H.S . Weinberg, P.A. Daniel and I.N . Najm,J. Am. Water Works Assoc., 1993, 85(1) , 73. 9. S.D. Chang and P.C. Singer,]. Am. Water Works Assoc., 1991, 83(3) , 71. 10. G.E. Speitel, J.M. Symons, A.C. Diehl , H.W. Sorensen and L.A. Cipparone, J. Am. Water Works Assoc., 1993, 85(5) , 86. 11. R.C. Hansson, M.J. Henderson, P. Jack and R.D. Taylor, Water Res., 1987, 21, 1265. 12. F.W. Pontius,]. Am. Water Works Assoc., 1992, 84(11), 22.

Brenton Nicholson (MRACI) heads the Organic Chemistry Unit of the South Australian State Water Laboratory, one of the partners in the Australian Centre for Water Quality Research. He manages the operation of the Unit which carries out monitoring for organics in water, as well as directing various research projects. These are currently focused on algal toxins but he maintains a keen interest and involvement in the area of disinfection by-products. He is a member of the NH&MRC/ ARMCANZ Organics Panel, the group which has developed the draft Australian drinking water guidelines for organic chemicals, including disinfection by-products.

Table 3: NH&MRC/ ARMCANZ Draft Guidelines DBP Guideline Value (1-1g/ L) Bromate Chloroacetic acid Chlorophenols - 2,4,6-trichlorophenol - 2,4-dic hl orop henol - 2-chlorophenol Ch loroketones Chloropicrin Cyanogen chloride Dich loroacetic acid Formaldehyde Haloacetonitriles - dibromoacetonitrile - dichloroacetonitrile - trich loroacetonitrile - bromoch loroacetonitr il e

444

20 1000

SilverPlatter Databases on CD-ROM

• • • • •

Waterlit Water Resources Abstracts Wastelnfo ASFA: Aquatic Sciences and Fisheries Abstracts Environmental Quality

For further information please contact

Electronic Media 648 Whitehorse Road Mitcham Vic 3132 Telephone (03) 872 3211 Facsimile (03) 872 4814

INNOVATIVE ELECTROCHEMICAL SENSORS LABORATORY- ENVIRONMENTAL - & - PROCESS - APPLICATIONS pH ORD D02 Stand ard or custombuilt versions for harsh conditions of temperature (high/low), high pressures. high/low pH .

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p H SCIENTIFIC PTY. LTD.

20 (2 µg/L aesthetic limit) 200 (0.3 µg/L aesthetic limit) 300 (0.1 µg/L aesthetic limit) Insufficient data Insufficient data 70 (based on cyanide)

50 500

MX

Insufficient data Insufficient data Insufficient data Insufficient data Insufficient data

Trichloroacetic acidl 00 THMs

250

Chemistry in Australia

esources

pool !lour Y d water with waste an

6 Hicks Avenue, TURRAMURRA, N.S.W. 2074 Phone: (02) 983 9ll2 Fax: (02) 983 9113

Treatment of Liquid Cyanide Wastes - Cont. from page 441 cyanide concentration and desired effluent. Required temperature is typically between 65 and 110 °C. Alkaline chlorination is often used for final destruction of residual cyanide. Due to economic reasons solutions containing less than 1000 mg/L of cyanide should be treated by other methods. 8 1. P. Doudoroff, "Toxicity to Fish of Cyanides and Rel ated Compounds; A review" , US EPA Report No. EPA-600/3-76-038, 1976. 2. L.E. Towill, J.S. Drury, B.L. Whitfield, E.B. Lewis, E.L. Galyan and A.S. Hammons, "Reviews of the Environmental Effects of Pollutants: Cyanides", Inter. Rep. No. ORNUEIS-81 and US EPA Report No. EPA-600/1-78027, 1978. 3. Australian Environment Council: "National Guidelines for the Management of Hazardous Waste", AGPS, 1986. 4. NSW Regulations for the Clean Waters Act. P~rt 3, Schedule 2, 1970. 5. Water Board Trade Waste Policy and Management Plan, 1994. 6. W. Lowe, "The Origin and Characteristics of Toxic Wastes, Reference to Metal Industries", Water Pollution Control, 1970. 7. Rohm and Haas Australia Pty Ltd: Technical paper on cyanide removal by ion exchange, Facsimile of 18 April 1994. 8. J.W. Patterso n, "Industrial Wastewater Treatment Technology", Butterworth-Heinemann, 1985.

August 1994 - Water Chemistry Supplement

Water (Supplement)

16


ENVIRONMENT

EFFECTS OF RESERVOIRS ON DOWNSTREAM AQUATIC HABITAT BL Finlayson*, CJ Gippel, S O Brizga Abstract Flows in Austra li an ri ve rs have been extensively modified by the construction of da ms and , espec ially in the south easte rn corner of the continent, the divertible water resources are now high ly utilised . Historically little attention has been paid to downstream aquatic habitat in the construction and operation of dams bur pressure on resources and a changed climate of expectation in the community now demand char environme ntal quality be restored and/or maintained. This paper derails the impacts of dams on rivers and ci tes three recent Australian case studies to illustrate the issues involved. The prese nt state of our understanding of the ecology of Australian aquatic commun ities limits our abi lity to manage regu lated rivers.

supply aspects and no attention at all was paid to the impacts of the dams and associated works on the downstream aq uatic environment. For example, and this is an issue which wil l be discussed furt her below, there was no analysis of the downstream effects on the Snowy River of diversions into the Snowy Mountains Hydro-Electricity Scheme until that by James in 1989, twenty-two years after rhe diversions began . A greater public awareness of th e issues of environm ental quality, rogerher with the face chat in some parts of Australia ri ver sys tems are nearly fu lly reg ulated , has led to ri sing co ncern about the downscream impacts of dams on aquatic habitat and the riverine environment generally. The extent to which rivers in Australia have already been regulated can be seen from

Figure 1 which shows the percentage of the divercible run off whi ch is already be ing diverted. Clearly, in southeastern Australi a we are now well advanced in chis extent. The consequences of chis are now beginning to be felt on a large scale. For example, ombreaks of blue-green algae which affect major sections of the Darling River cause serious problems for downstream and riparian water users and have become major issues of national political debate. Since the impac t of dams on the ri ve rs downstream was not considered at the time of dam construction, few dams have surveys of the river system carried out prior to regulation which can be used as a baseline against *Depanment of Geography, University of Melbourne, Victoria 3052

...

Introduction The variability of flow in Auscralian rivers led the European colonises of this country to insci cure a variety of river regulation schemes beginning with the histori c Tank Stream at the si te of the first se ctlemenc in Sydney Harbour (Aird, 1961 ). Greater demand for water and improved engineering technology have seen an escalation in the size of dams and water regulation schemes in the two hundred years since our European ancestors dabbled in the Tank Scream. As chose first settlers soon found our, Australian rivers are rather different hydrologically from the rivers of their hom eland s in th e northern hemisphere, in particular, Australi an rivers have more variable fl ows from year to year. The co nsequences of chi s for dam bu ilding are that in Australia dams must be much larger than those of Europe or orch America in order to ach ieve the same level of draft (at any given level of reliability) and this, when added to the losses from evaporation, means chat storing water in Australi a is, comparatively, a very expensive business (McMahon et al, 1992). Given chis, and the fact that until very recen tly Australia has been seen as a land of unlimited narural resources, it is not surprising that the design and implementation of river regulation schemes in the past has concentrated solely on the engineering and water WATER AUGUST 1994

I

I I I I

I

I

I

I

L________j __ _ I

I'

I I

% Divert ible runoff developed

~ 0-19

1::/:/:j

la

20 - 39

-

60-79

-

80 -100

o

I

40 -59

a~ 800 km

v

Figure 1 Percentage of divertibte runoff developed, mapped in water regions. (S01trce: McMahon and Finlayson, 1992)

15


tern of flows is also altered. • Dams which regulate releases downstream fo r irri ga ti on purposes: Many of Australia's large dams fall into this category; fo r exa mple, Eil don on the (Vi crori an) Goulburn River, Hum e on the Murray River and Dartmouth on the Mirra Mitta River. • Dams used fo r the generarion of hydroelecrricicy: Most major dams in Tasmania fall in to this category. The major fac tors of the downstream river system which are affected by dams include: • volume of flow • seasonal reg ime of flow • daily pattern of fl ow • extremes of flow (flood s and low flows) • wa ter qu ality: tempera ture, di ssolved oxygen, mrbidity, pH, conductivity and colour • sediment transport • fish passage • inv('. rtebrate drift Changes ro the flow regime im posed by th e da m lea d ro furth er changes in th e channel downstream of the dam, either as the namral channel system responds morphologically to the changed flows or by management activities. For example, river channels which are used ro convey water to downstream irrigation systems are usually managed so as to maxim ise the conveyance of the channel. To chis end obstru ction s in the chann els are removed, in particular large wood y debris (snags), thus eliminating a significant habi tat ele ment (Gi ppe l, O' eill and Finlayson 1992). In a natu ra l channel netwo rk , channel morphology is adjusted to flow such that as di scharge increases downstream so too does Impacts of Regu lation channel size (wi dth and depth ). It is the The effects of dam s on aquatic habitat fl oods of the river which determine channel downstream vary depending on the purpose size and although there is some debate about fo r whi ch th e dam has bee n built. Four the average frequency of the channel form ation di sc harge (bankfull di sc harge), it is classes of dams can be identified: • Dams used to sto re water for diversion generally accepted that it occurs about once inco another basin: The best known Aus- every two years (Selby 1985 ). Newbury and tralian exampl es are the dams on th e Gaboury (1993) have shown that the fl ow upper Snowy River (Eucumbene, Jind- whi ch maintains the im portant eco logical abyne and Guthega Pondage) from which and small scal e morphological characteristics water is diverted across the Divid e into of the channel occurs more frequently than the westward-flowing rivers of the Murray th e bank formin g di sc harge. Th ey have Basin . Dams used for urban water supply term ed thi s the channel maintenance di sand irri ga tion dams wh ere water is charge and it can be estim ated in the field released direc tl y into the distribution using standard techniques. Dams commonly system also fall inro this category. The eliminate the small fl oods from the downmajor impact of chis type of dam is a dra- stream channel and the chann el co ntracts. mati c reduction in flow in the channel Thi s sig nifi ca ntl y alters th e amount of in strea m habi ta t ava ilabl e and also leads below the dam at all times of the year. • Dams whi ch receive inter-bas in water to the simacion where large floods (say when transfers for release downstream: Dams in . the dam spills) cause catastrophic damage to the upper Murray Basin fall into chis cate- the channel. The width of the maintenance channel is gory, for example the Blowering Dam on the Tumut River and Khancoban on the a function of catchment area and can thereMurray River. The total volume of flow in fore be predicted for any point in a catchment the channels below these dams is greatly when thi s relationship has been established. increased, it usually has a different sea- The channel maintenance di sc harge can be sonal regime, and since these dams also determined in the fi eld by the slope-area generate hydro-electri city the daily pat- method and its frequency obtained from the which ro measure changes. These impacts now have ro be determined retrospectively, a process hampered by the fac t the Australian freshwater aquatic biology is poorly known (Williams 1973). The difficulty surrounding these issues can be illustrated by considering on e of th e few cases when a delib erat e attempt has bee n made ro moniror th e impact of a new dam from before the time of construction and ro spec ify environm ental flow levels which would maintain habitat. Prior to construction of the Thomson Dam, the Melbourne and Metropolitan Board of Works (now Melbourne Water Corporation) established and fund ed a committee to carry out baseline surveys, moni ror impacts and specify environmental flow releases. Even in th is seemingly ideal situation the committee found it diffi cult ro agree on an objectivelybased environm ental fl ow re lease strategy (Gippel et al, 1992) On e app roac h ro thi s probl em is ro assume chat the relevant measure of environmental healrh in a river is physical habitat availability rogether with warer quality and ro assess changes in these variables following regulation. In this paper selected examples of Australian rivers will be discussed to show how downstream habitat availability has been affected by regulation. Reviews of the literature and th e ge nera l principl es involved, based mainly on northern hemisphere experience, can be found in , for example, Ackerman et al (1 973), Ward and Stanford (1 97 9), Park (198 1), Lillehammer and Saltveit (1 984) and Pens (1 984). Examples of Australian work in this area are by Williams (1973), Bayley and Williams (1 974), Walker (1979, 1985) and Harris (1984).

16

partial-duratio1t,. flood series. In chis way the mag nitude and frequency of th e channel maintenance di scharge can be specified for th e chann el do wnstr ea m of a dam and incl uded in the environmental flow release strategy. An example of chis process is provid ed by Gippel et al (1 992) who warn ed chat the regulation of the Thomson River by the Thomson Dam would probably cause the channel width dow nstream of the dam ro contract from 22 m ro 7 m in the absence of regular channel maintenance floods. The persistence of a dam's impact on a river depends partly on the nature and severity of the impact and partly on the climatic characteris tics of the region through which the river flows. In humid climatic areas the impac t of regulation wi ll be mitigated by loca l run off and unr eg ul ated tri but ary inflows whi ch serve to resrore the natura l hydrologic regime. In areas where the downstream region is dry (subhumid , semi-arid or arid) the impact is persistent since there is no local runoff and few tribu taries ro mitigate th e effec ts. The Mur ray and the Darl ing Rivers, two of the major rivers of Australia, fall in to chi s category.

Examples of Regulation Impacts Surprisingly few derai led analyses of the down stream impacts of dams in Australia have been carried out and most of these are con ce rn ed pr imaril y with hydrolog ica l im parn (eg McCormi ck and Wall , 1980; Page, 1979; Riley, 198 1). Erskine (1985) has reporci d on th e downstream geo morphi c impact of the Gl enb aw n Dam, NSW. Erskine, Terrazzolo and Warner (199 1) have reviewed the impact of the Snowy Mountains Scheme on the channel of the Snowy River and Erskine et al (1993) have discussed the hyd rological and geomorphic impacts of the Eildon Dam on the Goulburn River. Among the available reports of biological impacts are those of Marchant (1 989) on the effects of the Thomson Dam on benthic invertebrate communities and Walker (1980) on the downstream effects ofLake Hume. Th e work of Mahes hwari , Walker and McMahon (1993) on the Murray River, one of the few studies to analyse both hydrological impacts and their ecolog ical implicati ons, illu stra tes th e probl ems of retrospect ive analyses of variable systems. In order to be able to compare observed conditions in any of the seven phases of regulation on the Murray with whar might have occurred natu rally (ie in the absence of reg ulation) they fo und it necessary to model natural flows for the time peri od in question. Given th e natu ral variability of flow characteristics, the flow record for the unregulated 'period (pre- 1922) cannot be assumed to be representative of the unregul ated fl ows in any och er tim e pe ri od . McMahon and Finlayson (1990) have illustrated chis variability using flow characteristi cs for successive twenty year periods on a selection of Australian Rivers. WATER AUGU ST 199L


110 100

Table 1 Streamflow characteristics of the Snowy River at DalMjy, Basin Creek and Jarrahmond before and after the constmction of the Snowy Mountains Scheme.

· · · · · · Beloit S.M.S. ( 11123 · 11150)

90

-

AllerS .M .S.( 11165-11187)

eo 70

Catchment (km')

60

Sice

Dalgety

3160

Basin Ck

11800

Jarrahmond

13400

"

,0

20 10

20

,0

~

so

~

ro

~

~

100

Spell duralion (days)

Figure 2 Frequency of low flow spell dura-

tions for spells below 225 Ml/day on the Snowy River at ]arrahmond, before and after the commencement of diversions through the Snowy Mountains Scheme (Source:James, 1989, Figure A2.4) •

300

•ei

Dam regulalion (1 944 GL/yr)

1950-67 1968-89 1936--55 1956--67 1968-78 1923-50 1969-88

17 21

Earl y Spring Moderare Spring

1187

19 12 10 27 19

Early Spring Earl y Spring Moderate Autumn

2056 2121 11 37 2020 1212

Early Spring Moderate Autumn

200

Site

ti

Date

100

=

:Ii

0

Cv

0.55 1.31 0.56 0.48 0.84 0.38 0.91

Maximum Mean Daily Dischar~e

.c

C

Flow Regime

ore: Flow regime classificat ion from Haines et al, 19881 1 - number of water years; Cv- coefficient ofvariation of annual flowJ calculated a1 the 111ea,1 annual flow divided by the 1/andard deviarion. Downstream distances: Dalgety 25 km ; Basin Creek 235 km ; Jarrahmond 264 km.

~

'6

N

Table 2 Flood magnitudes for selected recurrence intervals and flood variability (Iv) for the Snowy River at Dalgety, Basin Creek andJ arrahmond.

C:3 Flow transfer (1 677 GL/yr} •

:J' ~

Pre-regulation (1 294 Gl/yr)

Mean Annual Flow(Gl)

Daces

~

• Jjl l l I

I

Dalgety

j

Basin Ck

Jan Feb Mar Af,r May Jun Jul Aug Sep Oct Nov Dec

Month

Figure 3 Patterns of monthly flows for the

Tmmtt River for pre-regulation, a period of flow transfer (19 59-1969) and the flow regulation period since 1969. (Source: Gippel, O'Neill and Finlayson, 1992, Figure4.2)

Jarrahmond

1952--67 1968-89 1936--55 1956--67 1968-78 1923-50 1968-88

15 21 19 ll 10 27 20

Q20

Q2

Q

MIid

MIid

MIid

I,

55,778 25,050 199,852 14 1,306 403,790 217,360 371,943

20,2 19 3,349 44,096 55,949 45,377 57,902 38,349

24,8 1l 6,226 67,263 64,425 94,58 1 78,284 83,396

0.22 0.60 0.32 0.25 0.68 0.34 0.69

ote: Source: Brizga and Finlayson, 1992, Table 3 Ny- 111011ber of water year,; Q20, Q2 and Q twenty year reamwce i111erval, IUIO year rec111'J'ence inrerval and mean a111111al flood re,pecti11ely; Ii, - index of variabi/i1y of an1111al floodJ calmlared a1 the Jlandard deviation of the a111111al flood 1er·ie1 in the log do111ai11. 1

dam is such that it has spilled only five rimes in the period 1968 ro 1989. Pre- and postThe Snowy River: Inter-basin Snowy Mountains Scheme (SMS ) annual Transfers. The Snowy Mountains Hydro- flows are shown in Table 1 for gauging staElecrriciry Scheme was established by simul- tions at Dalgety, Basin Creek and J arrahtaneous ac ts of rhe Commonwealth , ew mond . ore rhe drastic reduction of flow in South Wales and Vicrorian parliaments in the pose- SMS period at Dalgety, located just 1948. The act specificall y provides that down stream of rhe dam. Table 1 also shows responsibility for downstream effects of the flows for stations furt her downstream. At Jardiversion of water from the Snowy River into rahmond , located close ro the mouth of rhe the Murray Basin lies with the stares of New Snowy River in East Gippsland, Vicroria, the South Wales and Vicroria which accepted this SMS has reduced the mean annual flow by responsibility in return for shares of the elec- 45% even though the Snowy River catchtricity generated by the scheme and the irri - men t above Jindabyne from which flow is gation water which would be made available diverted is only 14% of the rota! catchment in the Murray Basin . In retrospec t thi s area at Jarrahmond. In ad dition ro rh e effect on rhe mea n arrangement is logically flawed; the Snowy Mountains Authority has control over th e annual flow as discussed above there have also water but no responsibility for dealing with been changes ro the seasonal flow regime and problems caused by its diversion. The states the variability of annual flows (Cv). Iri each have responsibility bu t would have ro rene- case the annual variability has approximately go tiate th e agreeme nt if th ey wis hed to doubled after regulation. During the planning phase of the SMS it change rhe releases from the Jindabyne Dam inro the Snowy Ri ver. Little wonder then was widely believed char rhe scheme would that although the Jindabyne Dam was com- alleviate flooding of the Snowy River on the pleted in 196 7, no analys is of the down- flats around Orbosr in East Gippsland and for stream impac ts of the diversion was carried this reason the scheme was well supported locally (State Rivers and Water Supply Comout until 1989 Qames, 1989). The physiography of the Snowy Ri ver mi ss ion , 1949). Somew hat su rpri singly catchment is such that the headwater sec- perhaps, this has turned our nor ro be the tions, above the Jindabyne Dam, located in case. Table 2 shows the flood characteristics the highest mountains in Australia, have at Dalgery, Basin Creek and Jarrahmond prehigh precipitation, relatively low evaporation and posr-SMS rogerher with the index of and therefore hi gh runoff per unit area. variability (Iv), a measure of rhe variability of Releases from Jindabyne are small, sufficient the annual flood series. In all cases regulation only ro meet rhe needs of riparian owners . has increased rhe variabi lity of rhe annual downstream of the dam. The operation of the flood series, because regulation has a greater Three case studies are reported below ro illustrate some of the issues involved.

WATER AUGU ST 1994

impact on small floods than on large ones. At Dalgety, floods •of all recurrence inte rvals have decreased in magnitude, at Basi n Creek and Jarrahmond , short recurrence interval floods have dec reased in magnitude while, paradoxically, the longer recurrence interval floods have tended ro increase in magnitude. This is probably simply a reflection of the fac t that most large floods on the_Snowy River are generated by easterly low pressure systems off the New South Wales coast which mainly affect rhe headwaters of rhe Delegate River in the eastern part of the catchment. The Delegate River joins the Snowy River downsrream of Dalgery. The major visible impact of the changes ro flood behaviour as shown in Table 2 are ro be found in rhe channel of rhe Snowy River between the Jindabyne Dam and the junction of the Delegate River. The channel has dramatically contracted in size and become overgrown by vegetation, mainly exotic willows. These changes are illustrated using hisrorical and contemporary phorographs in Brizga and Finlayson (1992). · Below the Delegate River junction the major impact of the SMS diversions has been ro change rhe seasonal distribution of flows from a spring maximum roan autumn maximum (Table 1) and ro increase the duration of low flows. Figure 2 shows the frequency of low flow spell durations fo r flows below 225 Ml/day at Jarrahmond. While this is clearly a dramatic impact, its consequences have yet ro be clearly analysed. Irrigarors on the river flats below Jarrahmond report increased frequency of salt water incursions 17


A

B

The Tumut River: Inter-basin Receipts. Some of the water diverted our

before LWD removal

8

,

of the Snowy Valley is transferred inro the Tumur River, a tributary of the Murrum-

~!!~~~~~~i~;J

bidgee River. Water transferred through the mountains is used ro generate hydro-electriciry throughout the year and ultimately srored after LWD remova l in the Blowering Reservoir for release down the Tumur during th e irrigation season (Ocrober ro March). The effects on monthly D and annual flows are shown in Figure 3. Mean annual flow is now 1.5 rimes the preregulation flow ~nd rhe seasonal distribution of flows has bee·n reversed from a pre-regulation peak in late winter/early spring, followD' c' ing snow melt on the hi ghlands, to th e present situation where the channel is run at bankfull capacity for several months over rhe summer irrigation period and there is a flow m101mum rn winter. The increased discharge in the Tumuc River, especially the monrhs of continuous E F bankfull flow in the summer has led ro morphological ad justments in the channel. Bank stabilising vegetation along the bank, below the bankfull level, has been killed by the conF' E' tinuous inundation and the channel is widening. This is considered undesirable since the channel is flanked by a natural levee and bank erosion will ultimately destroy rhe levee and lower rhe channel capaci ty. To combat velocity (m / s) > 1·8 this, bank stabilisation works are carried our. 10m 0 1 8 - 14 At the same time an attempt is being made 1 4 - 10 to increase th e conveyance of the current CJ 10 - 06 no vert ical exaggera t ion channel by decreasing roughness. Thi s is CJ 0 6-0 2 0·2 m/ s isovel in ter val achieved,.by removing snags or large woody < 0 ·2 CJ debris (LWD) from the channel in the belief Figure 4 The distrib11tion of velocity at three cross sections on the Tmmtt River before and after the that they reduce veloci ry and rhe upsrream water level is raised . While LWD is removed removal of large woody debris. (Source: Gippel, O'Neill and Finlayson, 1992. Figure 4.20) ro maximise flow rare, this in turn leads ro excessive bank erosion necessitating further bank stabilisation works and also undermin30 min., max. ing trees along rhe bank which fall into rhe median 25 river and have ro be removed. There is evidence to indicate that the iJ removal of LWD is associated with a decline ;15 i in distribution and abundance of native freshg_ 10 obMMtd min., median, max. water fish (Cadwallader, 1978; Horde and ! modelled median Lake, 198 3). Koehn and O'Conner (1990) o,'-'---'-~ ~ ~ ~ - - ' - ~ ~ ~ ~ - - 'o,~-~--~-~~-~---' Jan Fab Mar Apr May Jun Jul Aug Sep Oct Nov Dec · 100 100 200 300 report stud ies which suggest that Murray cod •oo Distance from dam (km) and blackfish are dependent on submerged Figure 5 The annual tei11perature regime of Figure 6 Downstream trend in January logs for habitat and spawning sites. Gippel, the Gou/burn River below the Eildon Dam as water temperature fo r the Gou/burn River from ONeill and Finlayson (1992) charred the observed and as reconstructed assuming the dam upstream of Lake Eildon to dowmtream of Shep- effect of LWD removal on velocity disrribuwas not present. (Source: Gippel and Finlayson, parton. (Source: Gippel and Finlayson, 1993 , tion in cross-sections of the Tumur River. As shown in Fi gure 4, the removal of LWD Figure 7) 1993, Figure 6) smoot hs the veloci ty d isrri bmion in rhe section and removes areas of low veloci ry and inro the river as lower flows allow the salt exercised in NSW are nor seriously affecting dead water which may be important resting wedge of the estuary to extend further their distribution in the Snowy in Vicroria' areas for fish. Certainly the LWD provides upstream rhari previously. (p84). While such a conclusion from a fish cover for fish (Hall, 1989). Gippel , O' eill an8 Finlayson (1992) recIn the only study reported ro dare on fish biologist is encouraging, it must be tempered populations in the Snowy River, Hall (1989) with rhe knowledge rhar the sampling tech- ommend rhar LWD removal on the Tumuc stares that: 'Most species require access ro niques employed did nor permit an assess- be more selective and that wholesale removal brackish water or ocean waters ro complete ment of fish abundances, nor is there any such as has occurred in the past is unnecessartheir life cycles, and their presence in the pre-SMS fish population or species distribu- ily damaging ro the insrream habitat. They system - at least up until rhe !are 1970s - is tion data wi rh which the Hall (1989) data prov ide a methodology for calculating the an indication that flow regulation practices can be compared. afflux for any particular LWD accumulation ~

--

18

WATER AUGUST 1994


wh ich can be used to make obj ec tive decision s as to whether or nor ir should be removed. In addition to rhe habitat considerations, rhe removal of LWD is expensive and ir is surprising that prior co rh e work of Gippel, O'Neill and Finlayson (1992) there had been no rational decision-making procedure available for this purpose. In summary, rhe Tumur River has had its annual discharge increased by 50%, irs seasonal regime reversed, rhe parrern of occurrence of bankfull discharge changed from a frequency of about once every rwo years to continuous bankfull flow each summer for months on end , and almost complete removal of large woody debris in the channel. As is rhe case for the Snowy River, there are no baseline data for the Tumur River against which the impacts of these changes can be measured. The Goulburn River: Irrigation Flows. The Goulburn river in central Victo-

ria has a long history of regulation, the most recent and largest dam , Lake Eildon, having been completed in 1954. Lake Eildon is used as a storage for irrigation water which is used in rhe Goulburn- Murray Irrigation District. Warer released from Eildon is used to generate hydro-electricity and rhe channel of rhe Goulburn River deli vers irrigation water co the major offtake, the Goulburn Weir, 218 km downstream. Discussion in this section will ce ntre mainl y on the effects of Lake Eildon on water quality in rhe Gou lburn River wi th some sugges ti ons on how thi s problem might be addressed. This srrerch of river has been substantially modifi ed by these irrigation flows. Gippe l, Finl ayson and Th omp so n (1991) have analysed the effects of flow regulation on the hydrology of the Goulburn , in particular the frequency of overbank flows and the fill ing of floodplain wetlands. They show rhar close to the dam, wetlands which used to fill annually are now fi lled only three years in ten. This effect declines with distance downstream and little posr-dam change can be detected 200 km from rhe dam. Nathan (199 2) has also reviewed th e imp act of rhe dam on rh e hydrology of the Goulburn River. Erskine et al. (199 3) have reported on rhe impact of Lake Ei ldon on sediment load and channel stability of rhe mid-Goulburn River. They point our rhar channel response below the dam has been limited by the fact that there is less sediment available for deposi rion, flood flows have been red uced and as a result rhe channel has narrowed, bank erosion has been red uced and vegetat ion has increased on channel islands and in-stream bars. As is commonly rhe case in rhe examination of rhe im pacts of dams in Australia, there are no pre-dam water quality data for che Goulburn with which co compare the prese nt situation. Gippel and Finla yso n (1993) have dealt with chi s issue by generating water quality data for a site downstream of che Eildon Dam using observed water quality data in inflow screams. Despite WATER AUGUST 1994

the fact the Eildon is a large , deep re lease rese rvoi r, ir has no observab le impac t on dissolved oxygen levels. The dam does show an effect on pH, electrical conductivity and turbid ity though the effects are not large and probably do nor have any significant environmental impact. The dam does however drastically alter rhe temperature regi me of the river downstream (Fig ure 5). Medi an sum mer water temperatures are depressed by up to 7°C and median winter temperatures raised by up ro 2.5°C. Overall the effec t of the dam is co even our the seasonal pattern of temperature. Figure 6 illustrates the downstream trend in temperature for January and indicates chat the impact of che dam on water temperature has largely disappeared at Seymour, 138km downstream. These temperatures are unsuitable for the spaw ning of Macquarie perc h and river blackfish and rhis explains their absence from rhi s sec tio n of the rive r (Departm ent of Water Resources Victoria, 1989). Even under natural co ndition s ocher nati ve spec ies common in inland waters (Murray cod, silver perch , freshwater catfish, and golden perch) probab ly did nor spaw n in these waters because of low temperatures . The situation now is chat releases from Lake Eildon have rendered the Goulburn between rhe dam and Seymour (138 km of river) uninhabi table by the native species which used co live there, bur favo urable ro introduced spec ies , especially trour. Ic is technically feas ible, though quite ex pens ive, to manage the lake and th e releases so as to favo ur native fish over the introduced species and allow them to return to rhis section of the river. However, trout is a popular fish with recreational anglers , who are prepared to pay for fishing licences to fish for it, and a case can be made for continuing rhe present situation which favours it. Gippel and Fin layson (199 3) point out there are ot her probl ems (not ca used by rh e dam ) further downstream on the Goulburn which need to be addressed to improve native fis h habitat there. They suggest that licence fees from trout fis hing on rhe mid-Goulburn could be used ro defray che cost of improving native fish habitat in the lower Goulburn , a revenue-neutral outcome with benefi ts for rhe environment and for river users with a variety of interests.

Concluding Statement In this brief and limited discussion of the impact of dams on downstream habitat, one issue which has not bee n di scussed is rh e methodology for determining environmental flows. Currently available method s have bee n reviewed by Kinhill Engineers (1 988) All the methods reviewed have been developed overseas and there is clearly a need for serious research on the provision of envi ronmental flows for Australian conditions. Flow releases from dams for environmental purposes need

to provid e appijlpriate in-scream habitat , include floods of appropriate size and frequency to maintain the channel whi le still all owing rese rvoir managers to meet the needs for which the dam was built. Compromises such as rhac suggested above for the Goulburn wi ll no doubt be an increasi ngly important option in thi s area. The capital value of the dam and associated headworks and the retail value of water will be srrong constraints on environmental flow provision. In this context the case for environm ental flow releases will need to be based on strong and defensible evidence. Ir is here tha t rh e limi rations of our knowledge become glaringly apparent. It is possible to reconstruct pre-regulation flows, water quality and channel morphology sufficiently well ro detail the impact of regulation, as ill ustrated by the examples given above. What is not well known are the conditions necessary to maintain important aspects of the natural ecosystem. Since it is not feasible to return regulated rivers to thei r unregulated condition, we need to know the critical charac ter isti cs of flow, water qualit y and chann el co ndition whi ch wil l opt imi se in srream habitat. These are the research issues and their solution requires the genuinely interdisciplinary efforts of engineers, geo morphologisrs , aqu atic eco logists and system managers..

References Acke rman W C, Wh ite G F, and Worthi ngton E B, (Eds), 197.l , 'Man-Made Lakes: Their Problems and Envi ronmental Effec ts' , Geophysical Monog raph 17, American Geophysij;;il Union, Washington, DC. Ai rd WV, 196 1, 'The Water Supply, Sewerage and Drainage of Syd ney '. Metropolitan Water Sewerage and Drainage Board, S)'dney, 24 7pp. Bayley I A E and Williams W D, 1974 , '. Inland Waters and Their Ecolog)'', Longman, Melbourne. Brizga S O and Fin layson BL, 1992, 'The Snow)' River Sed imenr Srudy: Investigation intothe Disrribut ion 1 Transport and Sources of Sand in the Snowy Ri ver Between Lake Jindab)'ne and Jarrahmond '. Department of Water Resourcts Victoria, Water Rtsourct Management Series, Report No 81, 7.lpp. Cadwallader PL, 1978, Some causes of the decli ne in range and abu nda nce of nati ve fish in the Murra y-Darl ing system, Pmc Royal Soc Vic 90, 211-224. Depart ment of Water Resources Vic ro ria, 1989, 'Water Victoria: An Enviro nmental Handboo k', Victorian Govern ment Printing Office, Melbourne, 352pp. Ers kine W D, 1985 , Downst rea m geo morphic im pac rs of large da ms: the case of Glenbawn Dam, NSW. Applied Geography, S, 195-2 10. Erskine W D, Terrazzolo N and Warner R F, 199 1, Downst ream envi ronmental im pacts of the Snowy Mountains H)'d ro-El ectri c Scheme on the Snowy River, Austral ir Mitteil1111gsblatt des Hyd,·ographische11 Da11s tes in Osterreich, 6S/66, 5-6. Erskine, W D, Rutherfu rd, I D, Ladson, A R and Tilleard, J \V/ , 199.l . Flu vial Geomorphology of the Gou/burn River B"sin, Mid-Goul burn Catchment Coordinating Group ln. Gippel C J , Fin layson, B L and Thompson, B A - 199 1. Remote sensing of wetland warer reg imes and vegetation characteri stics Part II of Rapid Techniques fo,· Assessing Wetland Vegetation and Water Regime, Burea u of Rural Resources, Working Papter No . WP/12 /91, pp86- l 29. Gippel CJ , Marchant R, Stewardson MJ , Bri zga S 0 , Campbell I C, Woodfull J , FinlaysonB L and McMahon T A, l 992 . 'A review of environmental fl ow requirements of the Thomso nR iver from Th omso n Dam to Cowwaa r

19


\Y/eir', Report to Mel bourne Water Corporation: Centrefor Environmental Applied Hyd rology , University of Melbourne. Gippel CJ , O'Neill I C and Fin layson B L.1992. 'The hydraulic basis of snagmanagement'. Centre for Environmental Applied Hydrology , niversity of Melbourne, 116pp. Gippel CJ , and Finlayson, BL. 1993. Downstream environmental impaccs of regulation of the Goulburn River, Victoria. Hydrology a11d \11/ater Resou,-ces Sumposium, Newcastle 30 ]1111e-2 July 1993. The Institute of Engineers, Australia. Preprints of Papers pp33-38 (National Confe rence Publication No. 93/14). Haines AT, Finlayson B Land McMahon TA, 1988, A global class ification of ri verreg imes. Applied Geography, 8, 255-272. Hall D N, 1989, 'Prel imina ry Assess ment of Dail y Flows Required to Maintain Habitat for Fish Assemblages in the LaTrobe , Thomson , Mitchell and Snowy Rivers, Gippsland'. Dept Conservation, Forests and Lands Vic, Technical Report Series No. 85, 143pp. Harris J H, 1984, Impoundment of coastal drainages of southeastern Australia, a rev iew of irs relevance to fish migrations, Australia.11 Zoology, 21, 235-250. Hartle KG and Lake P S, 1983, Fish of channelized and unchan nelized sect ions of the Bunyip Ri ver, Victoria. Australian ]111 of Marine a.nd Freshwa.te,· Research, 34,441-450. James B, 1989, 'Snowy Mountains Scheme Effeccs on Flow Reg ime ofLower Snowy River', Ru ral \Y/ater Commission of Victoria, Investigations Report No 1989/13. Koehn J D and O'Conner \Y/ G, 1990, 'Biological Information for Management of Native Freshwater Fish in Victoria'. Dept Conservation and Enviro nment Vic, 165pp. Lill ehammer A and Saltveit SJ , (Eds), 1984, 'Regulated Rivers', Universitietsforlaget AS, Toyen , orway. Maheshwari BL, \Y/alker K F and McMahon TA, 1993, 'The Impact of Flow Regulationon the Hydrology of the River Murray and its Ecolog ical Implications'. Centre for Environmental Applied Hyd rology, Un iversity of Melbourne and River Murray Laboratory, Department of Zoology, University of Adelaide, l 54pp.

Marchant R, 1989. Changes in the benthic invertebrate communities of the Thomson River,southeastern Australia, after dam construction. Regulated Rive,·s: Research a11d Ma11ageme11t,4, 71-89. McCormick R and \Viall J, 1980, 'Preliminary report on the effects of dams on flood levelsin the Hunter River Basin '. NS\Y/ Water Resources Comm ission , Hyd rology Report 80147. McMahon T A and Fi nlayson B L, 1992, Australian surface and groundwater hydrology-reg ional characteristics and implica tions. In : J J Pig ram and B P Hooper (eds), 'Water Allocati on fo r t he Environme nt', Proc Intl Seminar and Worksh op, Centre for Water Policy Research, University of New England, Armidale, November 27-29, 199 1, 21-40. McMahon T A, Finlayson B L, Haines A T and Srikanthan R, 1992, 'Global Hydrology: Conti nental Comparisons of Annual Flows and Peak Di scha rges' , Catena Verl ag, Cremlingen- Destedt, l66pp. Newbury R \YI and Gaboury MN, 1993, 'Stream Analysis and Fish Habim Design', Newbury Hyd raulics Ltd and Manitoba acural Resources, Gibsons, B.C. , 256pp. Page K J, 1979, Al tered Hyd rologic regime of the Tumut River, New South \Y/ales. Geog,·aphical B11/leti11, l l , 133-1 39. Park C C, 198 l , Man, river systems and envi ro nmental impacts, P,·ogress in PhysicalGeography, 5, 1-31. Pem GE, 1984, 'Impounded Rivers: Perspectives for Ecological Management'. Wiley, Chichester, 326pp. Riley SJ, 198 l, The relative influence of dams and secular climatic change·on downst ream flooding, Australia. \\'later Resources B11/leti11, 17, 36 1-366. Selby M J, 1985, 'Earth's Chang ing Surface, an Introduction to Geomorphology', Oxford University Press , Oxford. State Ri vers and Water Supply Commission, 1949, 'Inland Diversion of Snowy River, Effect on Orbost Lands'. Internal Report, prepared by R G Webster, State Rivers and Water Supply Comm ission, Vic, April 1949. Walker K F, 1979, Regu lated streams in Austral ia : the Murray-Darl ing River system. In : J V \Via rd and J A Stanford (Eds) , 'The Eco logy of Regulated Streams', Plenum Press, New York , 143-163.

Walker K F, 1980, The de.wnstream effects of Lake Hume on the River Murray. In:~ D Williams (ed), 'An Ecological Basis for Water Resource Management', ANU Press, Canberra, 182- 191. Walker K F, 1985, A review of the ecological effects of river regulation in Australia, Hydrobiologia, 125, 111-129. \Viard J V, and Stanford J A, (Eds), 1979, 'The Ecology of Regulated Streams', Plenum Press, ew York, 398pp. Williams \Y/ D, 1973, Man-made lakes and the changi ng limnological environ ment in Austral ia. In: \YI C Ackerman , G F White and E B \Y/orchington (Eds), 'Man-Mad e Lakes: Thei r Problems and Environmental Effects', Geophysical Monograph 17, American Geophysical Union, Washington, DC, 495-499.

Authors Dr Brian Finlayson is Associate Professor and Reader in the Department of Geography and Adjunct Reader in the Department of Civil and Environmental Engineering at the University of Melbourne. He is a geomorphologist with interests in rivers and their management. Dr Chris Gippel is a Research Fellow in the Department of Civil and Environmental Engineering at the University of Melbourne. He is a geomorphologist who has worked extensively in the area of river management and the provision of environmental flows and also has specialist interests in water quality, especially turbidity. Dr Sandra Brizga is a Lecturer in the School of Environmental Planning and a Research Fellow in the Department of Geography at the University of Melbourne. A geomorphologist who has researched extensively in the areas of river system history and evolution she also now works and teaches in the broader field of environmental management.

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WATER AUGUST 1994


MANAGEMENT

COOPERATIVE FEDERALISM AND WATER REFORM JJ Pigram*, W F Musgrave, B P Hooper, NJ Dudley, M] Bryant Abstract Reform is currently high on the agenda of the Australian water industry. Corporacisacion of water authorities , revision of water charging and allocation mechanisms , and legislative changes in several Scares, reflect a renewed commitm ent by governments to cackle the pressing poli cy issues associated with the use and management of Australia's water resources. The Water Policy Agreement released by the Counc il of Australian Governments (COAG), along with significant policy initiatives by Scace Governments, signal a new urgency in the drive co promote efficient, sustainable use of water. Rather th an coe rcive instruments co promote a national approach, it is more likely chat cooperative federalism between the Scates and the Federal governments will succeed in overcoming insular decision-making.

Introduction During the past decade, the Australian water industry has been confronted by strong pressures for change. The water-using sector of the economy has come increasingly under criti cism as the perceived source of widesp read resource degradation and ex tensive impairment of riverine environments. At the same time, growing demands for alternative uses of water have arisen, for a range of envi ronmental purposes, and for recreation and tourism. To a large extent , these demands reflec t in creased environmental awareness and com munit y des ires for an improv ed quality of life. Satisfying these demands calls for far-reaching changes in water allocation systems and a new approach ro water management . There are now encouraging signs chat governments at all levels are seeking co respond positively co the challenges posed by a complex and evolving array of water issues and pri orities (Mull igan and Pigram 1989) The im pe tu s for reform in Australian water poli cy can be linked to a sw itch in emph as is from reso urce deve lopm ent co resource management. Marked fl uctuacions in technology and economic growth , accompanied by emerging environmental concerns and changes in social values and priorities in th e 1970s, und erl in ed a need for mor e responsive organisational structures and insti tutional frameworks. The process of ad justment has been ongo in g with conseq uent changes co ad mini strat ive arra nge ments , water allocation and pricing policies, and to WATER AUG UST 1994

the legislation which underpins the work of water authorities. Whereas such changes are welcome, reforms in the water induscry have freq uently been perceived as a function of political expediency. Therefore, it is encouraging co learn of decisions on water policy taken jointly by the Council of Australian Governments (COAG) at its meeting in Hobart in February 1994.

The COAG Water Pol icy Agreement The Council considered a number of measures designed co improve the efficiency of sectors of the Australian economy. Among these were proposals for sustainable water use and management. Before the Council was a report from the Working Group on Water Resource Policy chaired by Sir Eric Neal. The Working Group reported progress cowards reform in the water induscry and the minimi sation of unsustainable reso urce use. However, it also recognised a number of issues and deficiencies in vo lving water and related reso urces which cont inu e co require th e attention of governments. The Council endorsed the findings of the Working Group directed cowards remedying these deficiencies and associated degradation of the natural resource base. In particular, the Working Group targeted: • pricing reform, including full cost recovery and the removal of cross-subsidies • asset refurbishment • clarification of property rights ro water • allocation of water to the environment • ado pt ion of trading arra nge men ts in water • institutional and organ isational reform s, and • community consulrari on and ed ucation programs. The Agreement is see n as signalling a new urgency on the pare of government to promote effi cient, sustainable use of water in Austral ia.

Water Resources Policy

reservations on- the pare of some, co reduce greatly the reliance on command and control methods of water management, and ro rely more on the provision of a market framework within which water owners and users ca n manage the resource in a flexible, but socially and environmentally responsible way. However, some aspects of the strategy call for closer scruti ny. In particular, there is the problem of adequate recognition of the need co identify chose who gai n or lose as a result of its implementation and any consequential ad justment problem. Moreover, questions associated with the "needs approach" to the environment, along with a failure to come ro grips with the peculi ariti es of Australian hydrology, particularly its ex treme variability, and an apparent limited grasp of regional issues, an d of th e concepts of integrated catchment management, raise serious questions regarding ' the im plementation of the Agreement.

Pricing Reforms and Tradeable Water Entitlements The recommendations in the COAG statement for pricing regim es based on the principles of consumption-based pricing and fu ll cost recovery, along wi ch the provision that any subsidies should be made transparent, are welcome and consistent with reforms being implemented in most of the States and Territories of the Commonwealth. The provision for subsidy transparency is especially important, particularly as there will be situations where subsidy provision may provide th e onl y practicable means of welfa re support . In ge neral , however , meas ures intended to supplement incomes on welfare g rou nds should be divorced from water charges, if chose charges are to perform their effi ciency function effectively. A number of basic principles exist which should underpin water allocation , regardless of seccor or location. Thus , charges for irrigation as well as for urban water should involve an access fee as well as a fee for use. Similarly, volumetric enti tlements (or, preferably, Capacity Sharing, as discussed below) should be ap plied co mecrbpo litan bulk water consumers, as we ll as co irriga cors. Most importan tly, the recommendation chat future

Whereas there appears co be Ii ctle chat is new policy-wi se in the COAG document , it is significant in that it represents agreement at a senior level on a se t of overall policy goals fo r water management. In summary, *Centre for Water Policy Research, Unithe strategy amounts to a statement by all versity of New Eng land, Armid ale NSW Australian Governments, although with 2351

21


investment in rural water supply be undertaken only after appraisal indicates that it is economically viable and eco logically sustainable, should be extended ro rhe whole water induscry. The Council's endorsement of trading arrangements for water entitlements is also timely, as is the support expressed for crossborder trading , given certain qualifications regarding sustainability. Trans-basin and inter-secroral trade in water is a logical outcome of market reforms aimed at maximising economic and social benefits (Pigram 1993). The Council 's recommendation that improved management arrangements be considered for groundwater is also ro be commended. Reliable data on Auscralia's groundwater resources and their sustainability are deficient , and rh e potent ial of artifi cia l recharge of aq ui fers has be en re lat ively neglected in chis country. Moreover, pricing principles and rradeabilicy arrangements consistent with those for surface water resource use should also apply to gro undwater. In general, the scope for reforming and extending property rights ro facilitate the allocation of the resources of the riverine environment is nor well undersrood and requires investigation (Kaine et al 1991 ).

Asset Refurbishment Plans are well advanced for self-management by irrigacors of previously state-administered irrigation schemes in several regions in southeast Ausrra lia and the implications of chis were considered by the Council. Questions remain, however, concerning the viabiliry of some pares of older schemes and rhe responsibi lity for maintaining and replacing ageing assets. The COAG Agreement recommends the setting aside of funds for furure asset refurbishment. The suggestion seems ro be that such funds be built inro water charges. However, despite the imposition of asset levies, research has demonstrated that irrigacors, at least in some forms of irrigation , do nor have rhe capacity co fund the necessary upgrading of infrasrrucrure (Bryant, Faulkner and Drilon 1992). Such a situation will lead ro pressure co subsid ise refurbishment. As the viability of irrigation communities may be at risk, governments will find such pressure difficu lt ro resist. Should such support be given , and some already has, its existence and extent should be made clear, while a search should be initiated co identify scraregies for the achievement of sustainability of such communities. Ar least, research is called for ro clarify the extent ro which refurbishment of irrigation infrastructure is justified, and economic benefit demonstrated , and the manner in which cost-sharing can best be achieved.

Structural Change and Adjustment Adoption of a system of water management based on market-based allocation and full cost recovery will create large numbers of gai ners and losers, some of whom will be 22

regionally concentrated , particularly in the irrigation areas. The COAG strategy appears not ro recognise fully char the resulting pressures for scrucrural change and adjustment might call for policy action which would involve some compensation for the losers perhaps at the expense of the gainers. Thar is, the circumstances of some of the losers are such that they could not reasonably be expected to carry the burdens of adj usrment alone. This is felt ro be part icularly true of irrigation areas in the lower Murray-Darling Basin, documented in ABARE studies and reported in some derail by the Working Group on Water Resource Policy. Further, the errors of omission and commission which are being corrected are far from being entirely the fault of those who will be disadvantaged by reform . The case for compensation is nor weak. The reason for concern for the irrigation areas in this region is that they involve parallel problems of distorted water pricing smJCtures and environmental degradation in the form of high water tables , land salinisation and saline drainage return flows ro rhe river system. In some areas, the need to rep lace decayed infrastructure compounds these problems. Implementation of the COAG principles is doubly desirable in these areas because it will contrib ute , not on ly to the efficiency of resource use , but also ro the amelioration of the environmental problems. The benefits of such action are unlikely ro be captured, at least in their ent irety, by the farmers who will be directly affected by them. Indeed , many farmers cou ld be expected ro be net losers as a result. This is a matter of concern, as the little ev id ence which is available suggests that this will add to poverty problems, which perhaps only remain manageable by widespread supplementation of income off-farm. These problems appear ro be significant in irrigated horticulture and, perhaps , not trivial in the large fa rm secror (M usgrave and Brya nt 1993). Implementation of otherwise desirable policies could exacerbate the major structural adjustment problem which is developing in the lower Basin (Warson 1990). In its discussion of rhe issue of structural adjustment, rhe Indusrries Commission in its 1992 Report appeared to accept the need for planning, oversight and coordination of the resrrucwring process, and regarded the Irrigation Management Strategy of the MurrayDarling Basin Ministeria l Council as an important step in this direction. The purpose of the Strategy is " ... ro achieve an economically and environmentall y sustai nabl e and se lf- suffic ient irrigation indu stry in the southern Murray-Darling Basin by the year 2000. " Attainment of chis objective will require both th e implementation of the COAG principles and considerable ad justment and structural change. To be successful, the Strategy should includ e a policy concerned with such change, and the respective contributions of stakeholders involved . The

Report of the Working Group clearly indicates chat progress is under way in the preparation of such a po li cy, bur the feeling remains that explicit recognition of chis need in the COAG Agreement would have been helpful, at least by providing endorsement of such activity. Further economic analysis is also desirable of national, regional, and secroral gains and losses as a result of reforms in the water industry.

Environmental Allocations As noted above, the environment 1s increasingly recognised as a legitimate user of water. However, the wording of the COAG Agreement could convey rhe impression that environmental "requirements" are ro be mer regardless of coses. Such an interpretation really has two implications: that scarce water is always worth more co the env ironment than it is in alternative uses, and that the environment cannot do with less than the "requirement". While there will be some situations in which both of these are true, it is likely char a more flexible approach is necessary. Australia is a land of "droughts and flooding rains" and chis means that both the environment and ocher uses have fluctuating water demands. A balanced approach implies that there will be circumstances in which ei ther environ mental or alternative uses, or both, are able co get by with less than the ideal quantity without undue consequences, at lease for a rime while the extreme shortage lasts. In some cases, the resulting stresses may be compensated for by supplying additional water when it becomes more plentiful. This calls for a large amount of research into rhe effects of water shortages on both environmental and competing uses through rime, as well as research into flexible management policies co accommodate such variability. The problem remains of how ro make environmental allocations in situations where water resources are already fully comm iteed to other purposes. Whereas it can be argued that decision makers should consider the potential role of the marker ro enable smooch resource reallocations co occur, the quality of market outcomes is determined essentially by the system of property rights co rhe resources traded. Ir also should be noted that scientifically determined environmental requirements may be different from the socially optimal allocation. The environment is one of several competing uses, and the optimal mix needs ro be identified. The concept of Capacity Sharing offers a mechanism ro achieve this goal using market forces (Dudley and Musgrave 1988). Its potential for quantifying and minimising trade-offs between environmental and irrigation uses is curren'tly being researched (Dudley 1994). Capac ity Sharing is an in stit utional arrangement which can provide water users with clearly defined property rights and manage ment flexib ilit y, along wit h the abi lity co adjust reliability of supply co meer WATER AUGUST 1994


individual needs. Capacity Sharing differs from che commonly used method - release sharing - in chat individual users or user groups are able co score and manage independently their percentage shares of srorage capacity and inflows. Shares can relate co all types of water uses including irrigation , domestic and induscrial uses , inscream environmental and recreational uses, and wetlands. The system of property rights associated with Capacity Sharing is freely cradeable giving added flexibility and improved efficiency in water use through a water marker. Under Capacity Sharing, environmental groups would be encouraged co bid in the market for water co satisfy environm ental needs. This practice is growing in the western scares of America where public and private funds are allocated for chis purpose (Wi lley 1992) However, there is more co environmenta l use of water than merely making it available, and gaining an environmental water allocation is only a first seep. A management plan for the water is also necessary co ensure char it is put co optimum use for environmental purposes.

Integrated Catchment Management Integrated Catchment Management is a concept now widely endorsed in academic, professional and political circles, and it is being adopted and cried at several scales in the field of environmental resources management. Resource managers and researchers have long supporred planning and managing water and related land resources on a watershed basis. Rather than single -purpos e approaches, comprehensive planning and management have been widely advocated. In many ways, the watershed approach can be equated with the application of integrated watershed management. Such an approach includes interrelating the management of water quality and quantity, ground and surface waters, the land-water interface, biologic concerns, and the objectives of the user commun it y. Although int egra tion is endorsed by many, it appears difficult ro accomplish in practice. One reason for chis may be char coo much emphasis is placed on planning and inter-agency cooperation and nor enough on the problems of management of common property which und erpin the concept (Musgrave and Sinden 1988). The COAG Agreement supports and promotes the use of Integrated Catchment Manageme nt , bur does nor progress the impl ementation of chi s approach mu ch beyond "motherhood statements", and a general call for more widespread use. Furthermore, che development of appropriate adm inistrative arrangements and decision-making processes is nor derailed. This is most likely due co the significant institutional constraints on implementation chat exist in Auscralia. There is also no reference in the document co the need for the development of perforWATER AUGUST 1994

mance indicacors chat demonstrate the gains achi eved from using an Integrated Catchment Managem ent approach. Measures of coral system health are needed , rather than purely functional measures of ecosystem components, and one-dimension variables , such as scream salinity concentrations.

Consultation and Community Education The COAG Agreement makes usefu l comments about community consultation and education, and makes strong recommendations ro lift the profile of consultation regarding reforms advocated by the Council. Whereas the Agreement makes expli cit reference co the need for improved community consulcacion, no appropriate mechanisms are mentioned. These are imporrant because there is evidence co suggest chat some community consultation processes can unduly retard the impleme ntation of sustainable water resources management practices (Hooper 1994). The Agreement could be more explicit by suggesting, for example, that it be mandacory for community representation on catchment management crusts and river basin management authorities. New methods of community representation would be needed ro achieve chis, and it might be timely for a strategic national review of community consultation in water resources management ro be und ertake n. Such a review should aim co identify the constraints ro the adoption of effective community consultation, once defined. The COAG Agreement is ro be commended in chat its view of water ed ucation includes schools, and a broader public education program. However, the Agreement could go furrher, and consider che development and implementation of a acional Water Education Program. This could be developed under the auspices of ARMCANZ, in conjunction with the appropriate national education curriculum committees. The latter are developing a new national education agen da throughout Australia, and there is an ideal opporruni cy at present co promote integrated approaches co water resources management as parr of the national school curriculum. A further development in chis direction could be the estab li sh ment of a National Water Education Foundation. The mission of the Foundation wou ld be ro develop and implement water edu cation programs, leading co a broader understanding of water issues and their resolution. The Foundation would promote an integrated environmental management approach to water use, one chat recognises the interdependence of natural resources and resource users, and which strives for ecologically sustainable water use on a catchment basis. A National Water Education Foundation could have the following roles: • Promotion of sustainable water resources management and its reaching across all sectors of the education system;

• Coordinacren nationally of public education in water resources management and che provision of adult education courses; • Formation of a peak national forum for discussion of water quality and quantity management issues, organisation of workshops on these themes, and promotion of improved water resources management through media releases, and pub li shed material; • Sponsorship of scholarsh ips and achievement awards for research and omstanding best practice water resources management in industry, agriculture , commerce, and catchment management. It is envisaged that the proposed National Water Education Foundation would be funded partly by private industry and partly by federal and state governments, and governed by a Board of Directors consisting of representatives of community, business , and environm ental interests, and resource management agencies. Significant pares of its program would be self-funding.

Water Reform Initiatives The COAG Agreement marks a renewed interest by governments in water reform and has been matched by a number of significant initiatives in the Federal and State spheres.

Federal Initiatives At the national level, the Federal Government's recerft White Paper, "Working Nation ", outlined several regionally based infrastructure investment projects as pare of a comm it:p1 enc co pursuing an accelerated water reform agenda. In the Goulburn Valley of norrhern Victoria, for example , $6 million will be provid ed over three years co develop a best practice model for sustainable regional development through erihanced water quality management. In the Sunraysia Irrigation Region , a land and water management project will be established, at a cost of $2.55 million, co deal with the region's serious salinity and drainage problems. An integrated strategy involving water supply and drainage infrastructure , land consolidation, and rural adjustment is co be directed cowards repairing major salinity damage and raising productivity. Federal funding will also be provided co establish an Environmental Policy Analysis and Research Program within che Industry, Science and Technology porrfolio. This initiative has clear implications for che development and implementation of efficiently designed environmental policies affecting the water induscry. In June 1994, the Federal government pledged a further $6 million for research into scream pdllmion and a national system for assessing river health.

State Initiatives At the State level, moves have been under way for some time ro bring about muchneeded reforms co water management and co

23


the protection of waterways and water quality. having delegated responsibility to provide a In Queensland, for example, a review of full range of rural water services. These pricing policy for water supplied from Scace- Boards are now to becom e separate authoriowned infrastructure has been undertaken ties with additional responsibility for headand a policy options paper released for public works operations , and the Rural Wat er comment. Enactm ent of preferred tar iff Corporation ultimately will cease to exist. In the urban water secco r, Melbourne structure options, along with security and cradeabilicy of water entitlements, and alloca- Water Corporation is being set up as a comtion of uncommitted water, is expected lacer mercial organisation for the core functions of water supply, sewerage and drainage services. chis year. Tasmania is redrafting the Scace Water The Corporation 's existing contracting-out Act and associated Acts and chis may call for program will continue, with responsibility wider reforms in areas such as water pricing for provision of public goods such as parks and transferability. Likewise, in the Northern and waterways clearly separated from its core Territory, a new Water Act came into force function. Amalgamation of non-metropolitan in 1992 to clarify and screngthen the Power urban water authoriti es inco a small er and Water Authority's role in managing the number of commercially viable organisations Territory's water resources. A draft strategic is expected to generate operational savings plan, T Wate-1; was released this year high- through economies of scale. In a further attempt to encourage more lighting poli cy issues including, in particular, those relatin g co water qualit y and flexible water allocation , a special cask force has been fo rmed to establish expli cit traderesource allocation. A Strategic Direction Plan has also been able water entitlements and a framework to drawn up in Western Australia incorporat- facilitate much wider market operations in ing micro-econo mi c reform of the Water water among irrigation interests and between Authority, and endorsement of Total Quality urban authorities. Apart from moving water Management to provide greater accountabil- co higher and better uses, water trading is ity and improved operat ional performance. expected to generate valuable cash flows and Corporacisacion of the Authority is und er provide savings in infrastructure investment. consideration and a number of policy options New South Wales has also been in the are also being pursued, including further forefront of reforms co the water industry tariff reform s for metropolitan and non-urban in rece nt yea rs. Poli cy initi atives includ e water users, and possible privatisation of the pioneering work in Total Catchment Manirrigation discribucion system. agement, restrucruring of urban and rura l In South Australia, responsibility for water charges, nutrient and salinity managewater management is now split , wi th the ment strategies , corpora ri sac ion of major water resources function transferred co the urban water authorities, and moves towards Department of Environment and arural a more flexible, marker-driven water allocaResources. The management of uti lities and c10n system. services remains with the Engineering and These initiatives culminated in the release Water Supply Department, which is co be in June chis year of a White Paper outlining corporatised and co out-source many of its sweeping reforms to the management of the fun ctions in operations and maintenance . State's rivers and waterbodies (New South or surprising ly, in view of its rather arid Wales Government 1994). Key points in the nature, South Australia has been something new structure are: of a pacesetter in water reform and further â&#x20AC;˘ Establishment of a Catchment Assessment policy initiatives can be expected under the Commission to make recommendations to new organisational structure. the Government on water quality objecIn Victoria, key components of a reform tives and uses of water for each catchment agenda are being pursued, aimed at introducin the Scace ing competition into the water indu stry â&#x20AC;˘ Establishment of an Office of Water (in (Department of the Treasury 1993). place of the existing Water Resources According co the Department of Water Council) with a broad advisory and stewResources, Victoria (1992, 3), " ... the 1980s ardship role directed cowards policy coorsaw an unprecedented level of review and dination between land and water reform in Viccoria 's water industry". Th e management. decade culminated in the Water Act of 1989 The new arrangements will complement which marked a new thrust cowards scream- the current responsibilities of agencies such lined institutions based on modern economic, as the Department of Water Resources and social and environmental principles. the Environm ent Protect ion Authority in The Water Act brought together many of water management . Although the proposals the recommendations of the Public Bodies have received a mixed reception from irrigaReview Committee which initiated progres- tors and environmental groups , these reforms sive restru cturing of the water industry. are expected to contribute to the adoption of Further reforms fo ll owed a review of the realistic, achievable water quality objectives Rural Water Commission (the McDonald and workable approaches co th e sharing of report), and as a result, the Rural Water Cor- water (including environm ental allocations), poration was set up as a statutory authority, spec ifi c co ind ividual catchments and river with five Regional Manage ment Boards systems. They should also provide the neces24

sary condicion~for th e es rabli sh ment of secure and tradeable property rights in water. In a further major reform the ew South Wales Government in May 1994 passed legislation for the transfer of manage ment and ownership of rural irrigation schemes from the Department of Water Resources to irrigation interests. Initially, corporations will be sec up to manage and operate the schemes as an interim seep cowards full auronomy and irri ga ror ownership. Irr iga cors will be expected to establish a commercial business structure incorporating managerial arrangemen ts for fina cial responsibility and accountability. Although Irrigation Management Boards have expressed support for the transfer, the move has impli ca tions for ongoing responsibility for asset maintenance. Negotiations are continuing over Govern ment support for a capital refurbi shm ent program co ensure that water supply delivery and drainage systems are upgraded to acceptable standards. To a considerable deg ree, th e reform s enacted and proposed in Australia's states and territories represent a new decision environment for water resources manage ment in this country. These reforms are welcome and form part of wideranging, and sometimes quite rad ical moves co invigorate lagging economies . At th e same time , accelerated change has the potential co compromise the very levels of service delivery cowards which it is targeted. In the reform process, care will be needed co ensure that the established core of technological and managerial expe rtise, essentiaJ.. co the fun ctioning of the Scares' water systems, is not bypassed in the pursuit of un realis ti c levels of performance and efficiency.

Summary Clearly, the pace of reform in the Australian water industry has stepped up in the past decade , marked by a se ries of poli cy initiatives by both Federal and Scace Governments. Th e deliberations of the Working Group on Water Resource Poli cy, and the Water Poli cy Agree ment endorsed by the Council of Australian Governments, represent significant milestones cowards establishing a strategic framework for ongoing reform. However, organisation of Australia's water resources is fragmented across pol itical and interjurisdicrional boundari es, and concern over the erosion of "Scares Ri g hts " and responsibilities remains close co rhe surface in Federal-Stare di scuss ions on resources policy. Contrasts in rhe resource endowment too, and diverse environm ental co nditions ac ross the conrinenr, make difficult the achievement of a homogeneous ser of insrirurions for rhe ad minisrrarion and management of water nationwide. Yer many warer-relared issues do not respect artifi cial political barriers, and call for coordination and collaboration in state and reg ion al infrasr rucrnre and expertise. The Murray -Darling Bas in Commission is an example of what can be achieved. WATER AUGUST 1994


In chis context, rhe Water Policy Agree- achieving a comm on approach to enactment ment, like COAG itself, is an unusual demon- of rhe reforms proposed. stra ti on of rh e work ing of coo pera ti ve Aga in st ~his backgro und , rh e COAG federa li sm. For rhe various governm ents of Water Poli cy Agree ment se rves notice on the federation to agree publicly to principles the Scares char thei r scope for independent, fo r water poli cy reform , along with a and perhaps in sul ar dec ision making, is rim erabl e for th eir impl ementation , is now quire lim ited. The dom inance of Canremarkable. Wh ile rhe Agreement has some berra over resources fu nding, and the abili ty weaknesses, ir is an impressive instrument for of rhe Federal Governm ent to make support mi cro-econom ic reform of a sector suffering for water resource development cond iti onal upon meeting Commonwealth policy objecfrom some severe regulatory distortions. How the Agreement is ro be enfo rced, ti ves, must have a powerfu l bearing on the however, is nor clear. In all probabili ry there future pace and direction of water reform in is no prov ision for such acti on, apart from Ausrralia. reporting requirements and expectations of accountability in meeting Agreement targets. References Such a siruarion may cause concern to those Brya nt M J , Faulkner R J and Drilon ML (1992). 'Horticulwho see k expli cit provi sion fo r coe rcive tu ral Viability and Future Irrigation Supply Options in the MIA'. Report to the Murrum bidgee Irrigation Maninstruments to guarantee a bind ing contract. agement Board. Centre fo r Water Policy Research, UniHowever, the hi story of cooperative federalversity of New England. ism in Australia is such as to suggest char Department of the Treasu ry (1993). "Reforming Victoria's moral suasion itself may be adequate in many Water Industry', the Office of Stare Owned Enterprises. Melbou rne. Department of \Xlarer Resources, Victori a situations. Time wi ll cell whether this will be (1992). 'A Scarce Resource', Melbou rne. so in the case of the COAG Water Policy Dudley N J (l 994). Simultaneous reduction of risk to irrigaAgreement . tion and envi ronmental uses fo r reservoir wa ter, forrhcomAr the same rime, the Agreement could ing in Y Haimes, D Moser and E Srak hiv (eds) ' Riskbe seen as marking the emergence of a more Based Decision Making in Water Resources VI' . American Soc iet)' of Civil Engineers, NY. tangible Federal presence in water resources management in Australia. Whereas broad Dudley N J, and Musgrave \'(I F (l 988). "Capacity sharing of surface water reservo irs'', \\Yater Resources Research, agree men t appears to have bee n reac hed 24( 5), 649-658 on progress cowards water refor m, the most Hooper B P (l 994). Constraints on and opportunities for rhe implementation of best practices in integrated land and difficult phase of the reform process has sti ll wate r management . Fifth Intl Sy mp on Soc iety and to be addressed - that of implementation. Managemenr. Fort Collins, Colorado, June. The role of the Federal Government may well KaineResource G, Mu sgrave W, Burto n J and Brya nt M (199 1). be criti cal in overcoming possible Scare and Towa rds Int rod ucing Markets fo r Riverine Resources. secr ional mi sg ivings and obj ec tion s, and Report to the New South Wales Depart men t of Water Resources. Centre fo r Water Policy Research, University

of New England, 34 pp. Mulligan H and Pigram J J (l 989). Water Administration in Austral ia: Agenda for Change (Occasional Paper No 4). Centre fo r Water Policy Resea rch , Un iversity of New Eng land. Musg rave \'(I and Sinden J (1988). An economic view of integrated catchment managemenr. AWRC National Workshop on Integrated Catchment Management , Univers ity of Melbourne, May. Musg rave W F and Bryan MJ (1993). Adjustment in the irrigation industries of the Murray-Darl ing Basin, Symposium on rhe Future of Irrigation in the Murra)1-Darling Basin , Griffith , August. 1 ew South Wales Government (I 994). The Management and Regulation of Water in New South Wales, Offi ce of the Premier, Sydney. Pigram J J (l 993). Properc y rights and water markets in Ausrral ia: an evolutio·nary process cowards instituti onal reform , \Valer Re1011rces Research, 29,4, 1313-19. Warson \'(I ( 1990). An overview of water sector issues and initiatives in Austral ia, in: Pigram J J and Hooper B (eds) Transferability of Water Enti tlements. Proc Intl Seminar and Workshop, Centre for Water Pol icy Research, University of New England. Wi lley Z ( 1992). Behind schedu le and over budget: the case of markers, water and environment. Harvard J Law Public Pol, 15,2, 39 1-425.

Authors Research fo r this paper was carried out in the Centrefor U'later Policy Research at the University of ew England Professor John Pigram is Exemtive Dire/"tor of the Centre and Associate Professo r of Geography and Planning. Professor Warren Mu sgrave is Director of the Centre and Dean of Econom ics, Business and Law. Dr Bmce Hooper is Research Fellow and Dr Norman Dudley is University Fellow attached to the Centre, while Mr Michae l Bryant is 5-lnior Project Di-recto,:

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MEET MELBOURNE WATER Report by Michael Muntisov The June meeting of the Victorian Branch aimed to outli ne Melbourne Water's current and future strateg ies and che impact of che corporate reforms. Over 100 members mended, including a number of well-known personalities from the pasc, curious to find our what was going on. David Lynch, Chief Manager of Corporate Scracegy, provided some background and recent history ro reforms in Melbourne Wacer. The Treasurer's Apri l 1994 economic scacement has foreshadowed che division of Melbourne Water into 5 separate business: • Headworks (Wholesale) • Melbourne Parks and Waterways • 3 Regions (Retail) The features which are seen to be important in che proposed reform model being pursued by che Government include: • efficiencies driven by (yardstick) compecicion nor economics of scale • customers belong to che retail businesses • demand is driven by che retailers • strong com mercial arrangements between retailers and wholesalers • high degree of autonomy wich individual boards

The businesses will be granted operating licences for monopoly provision of services. The licences will nor be contestable initially ie they will be Scace-owned. Each business will report direct to Government. A range of issues was scill under consideration wich respect ro operating licences . These included: • process based vs rightly prescribed ourcomes • amendments to licences • role of economic regulator • bulk wacer enti dements • environmental and water resource requirements Although che overall model was in place, considerable work was required to resolve che various outstanding issues and derails. In a broader sense ic was critical chat che framework of accountabilities between various government ministries were well understood and defined. Rob Skinnet; General Manager - Water Services , spoke briefly about Melbourne Water's philosophy on Core vs No n-Core act1v1ttes. He explained how Melbourne Water had reduced its permanent workforce from 8,000

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to around 2,500 presently. This was achieved by being more efficient, contracting our and by simply not doing things which were nor obligatory. Savings of over 20% had been achieved in some areas by contracti ng our. Frank Burfitt spoke on the development of a master strategy plan for wacer and sewerage. He defined master planni ng as a business planning process wh ich determines directions for the next 10 to 20 years and is reviewed every 5 years. The master plan provides a framework for making decisions. Ir involves co mmunity agreement on trade-offs between price and service. This permits the definition of future requirements for cap ital investment and setting of priorities. Geoff Gardiner spoke on Melbourne Water's asset management system which is a strategic activity within the Corporation. This system of grad ings was set up in a macrix format and allowed all assets to be classified and prioritised. Rehabilitation of all assets rated as Condition 5 and Condition 4 AAA is undercake'n immediately. Peter Harford, General Manager Cusromer Services, spoke on various aspec ts of customer ervice. Peter described the proposal for improving servi ces to the development industry. These included over the counter serv ices for smal l developmen cs ( < 4 uni ts) by 1 July and che appointment of dedicated cl ient managers for major projects. Developers will be required ro be cert ified to AS 3901 by 1 July 1995. In che area of cusromer guarantees/levels of services a number of additional proposals were under consideration.

Questions In response to che question of what incentive was there for che new retail businesses to practice demand management , it was suggested char there would be a financial incentive to reduce discribucion system leakage and to reduce the quantity of discharge co sewer. Ir was also likely char requirements for demand management would be included in che operating licences. On the question of whether the new retail businesses would cur-off water supplies to properties for non-payment, Peter suggested char it was the Government's obligation for the soc ial welfare of the com mun ity, not Melbourne Water's. Thi s highlighted the need to define comm unity service obligations in the operating licences. He also scared char no consideration had been given to prepay com meters. WATER AUGUST 1994

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