Water Journal September - October 1997

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Volume 24 No 5 September/October 1997 Journal Au stra lian Water & Wa stewater AssociationEditorial Board F R Bishop, Chairman B N Anderson, G Cawston, M R…
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Volume 24 No 5 September/October 1997 Journal Au stra lian Water & Wa stewater AssociationEditorial Board F R Bishop, Chairman B N Anderson, G Cawston, M R Chapman P Draayers, W J Dulfer, GA Holder M Muntisov, P Nadebaum, J D Parker A J Priestley, ] RissmanGeneral Editor M argaret M etz AWWA Federal Office (see address below)Features Editor EA (Bob) Swinton 4 Pleasant View Cres, Glen Waverley Vic 3150 Tel/Fax (03) 9560 4752Branch Correspondents ACT - Ian Bergman Tel (06) 248 3133 Fax (06) 248 3806 N ew South Wales - Mitchell Laginestra T el (02) 9412 9974 Fax (02) 9412 9676 Northern Territory - Bill Bean Tel (08) 8924 7201 Fax (08) 8941 0703 Queensland - Tom Belgrove Tel (07) 3810 7967 Fax (07) 3810 7964 South Australia - Peter Marrin T el (08) 8303 8723 Fax (08) 8303 8750 T asmania - Ed Kleywegt Tel (036) 238 2841 Fax (036) 234 7109 Victoria - Mike Muntisov Tel (03) 9600 1100 Fax (03) 9600 1300 W estern Australia - Jane Oliver T el (09) 420 2462 Fax (09) 420 3178CONTENTS From the Federal President ....................... ... ....... ...... .. ... .... ......................... .. 2 From the Executive Director ....... ..... ... ..... ..... .... ............ ... ...... ... ..... ..... ... ........ 4 MYPOINTOFVIEWBiodiversity-We Depend On ItA Jones ............ ........ ......................... ..... ................. ............. ......... ... ........ ..... ..... 3 INDUSTRYPEOPLEProfile-Sandra BurkeC Porter ... .. .. ..... ............... .... ..................... ...... ............... ... ..... ... ...................... .. 6 WATER Needs, Challenges and Health Benefits of Drinking WaterR H elmer ......... .......... ............... ....... ... ...................... ........ ............... ... ...... .. .. .. 10 WATERQUALITYRESEARCHFrom Catchment to Tap-Supplying Affordable, High-Quality WaterBursill, T Priestley .... .. ............. ... ..... ... .... ..................... .......... ........... ................ 13Advertising & AdministrationRecreational Water Guidelines for CyanobacteriaAWWA Federal Office Advertising: Anne Adams Graphic Design: Elizabeth W an PO Box 388 Arcannon NSW 2064 Level 2, 44 Hampden Road, Arcam1on Tel (02) 9413 1288 Fax (02) 9413 1047 Email: awwa@inta.net.auL S Pilotto, M D Burch .. ..... .............................. ............... ........ ......... ... .. .......... 17Water (ISSN 0310 ¡ 0367) is published six times per year: January, March , May, Ju ly, September, November byAustralian Water & Wastewater Inc ARBN 054 253 066Federal President Mark P ascoeExecutive Director Chris D avis Australian Water & Wastewater Association assumes no responsibility for opinions or statements of facts expressed by contributors or advertisers and editorials do not necessarily represent the official policy of the organisation. Display and classified advertisements are included as an inforn1ation service to readers and are reviewed by the Editor before publication co ensure their relevance to the water environment and to the objectives of the Association. All material in Water is copyright and should not be reproduced wholly or in part without the written permission of the Editor.Subscriptions Water is sent to all members of AWWA as one of the privileges of membership. Non-members can obtain Warer on subscription at an annual subscription rate ofS39 (surface mail).Blue-green Algae and Drinking Water QualityD A Steffensen, B C Nicholson, MD Burch, M Drikas, P D Baker ...... ....... ... 19 Beyond Collforms-Measurlng Human HealthME Hellard, M I Sinclair, G Ranmuthugala, LS Pilotto , A Padiglione, B E Robertson , C K Fairley .................... .. ....... ... ........... .. .. ... .... ..................... .. 26 Natural Organic Matter- The Curse of the Water IndustryM Drikas ... ................ .............. ..... ... ....................... .. ................. ..... ....... .... ...... 29 Predicting and Maintaining Drinking Water Quality in Distribution Systems G Kas tl, I Fisher ............... .. ...................... .... .... ..... .......... ....... .......................... 35 WASTEWATER Biological Nutrient Removal- Present Status and Future DirectionsJ Keller, K J Hartley ........ ... .............................................................................. 39 ENVIRONMENT Sweet Smell of Success for Odour Interest GroupM Laginestra .................... ....... ..... .. .......................... ......... ............................... 41 BUSINESS A Quantum Increase In Wate r PricesJ Crockett, L Carroll ........................... ........... ............. .. .. ........... ... ............ ... .. .. 43 DEPARTMENTS International Affiliates .......... .... .... .... .............................. ...... ........... ............. 8 From the Bottom of the Well ......................................................... ........... ..... 2 Meetings ........... .. .. .... ... ........... ..... ...... .... ..... ... ............ .... ..... .. .... ..................... 48 New Products ...... ... ........ ....................... ........ ............. .. ..... .... ... ................... . 47 OUR COVER : Clean W ater for Future Generations The CRC for Water Quality and Treatment carries out research, education and training aimed at assisting the Australian water indust1y to supply clean, affordable water for present and future generations. Photograph by Wendy Easton of her son, Giles, aged 4. Photo courtesy of CSIRO Molecular Science (formerly Division of Chemicals and Polymers), a participant in the CRC for Water Quality and Treatment.WATERNEEDS,CHALLENGES AND HEALTH BENEFITS OFDRINKING WATER R Helmer Abstract The global situation in the area of water and health is characterised by large population groups in developing countries which are excluded from adequate supplies of safe drinking water and from suitable sanitation services. The resulting diseases are most prevalent in areas of rural and urban poverty. Improvement in water supply usually includes disinfection by chlorine. Related risks and benefits of a chemical and microbiological nature have to be assessed in comparison. The World Health Organization (WHO) Guidelines for Drinking-Water Quality provide the basis for risk assessment and management. They also cover the setting and application of national standards.Key Words Chlorination, developing countries , disinfection, disinfection by-products, drinking-water quality, health risk assessment, infectious diseases, urbanisation, water resourcesIntroduction The Mar del Plata Action Plan, adopted by the United Nations Water Conference in 1977, already stipulated that 'all peoples, whatever their stage of development and their social and economic conditions, have the right to have access to drinking water in quantities and of a quality equal to their basic needs' (United Nations, 1977). This gigantic task of providing all peoples with their legitimate share of potable water must be tackled on three battlefields: hundreds of millions of rural and urban dwellers are without safe water or sanitation, millions of infants perish every year due to diarrhoeal diseases in the developing world, and a water crisis is looming over many developing and also some industrialised countries. Most of the serious diseases and lifethreatening hazards associated with drinking water are microbiological in 10WATER SEPTEMBER/ OCTOBER 1997nature. As indicated in C hapter 18 of 'Agenda 21' of the United Nations Conference on Environment and Development (UNCED, 1992): 'An estimated 80 per cent of all diseases and over one third of deaths in developing countries are caused by the consumption of contaminated water, and on average as much as one-tenth of each person's productive time is sacrificed to water-related diseases.' Diseases caused by microbial pathogens in drinking water are concentrated in the developing world and among the poor urban and rural households. In response to these challenging needs the supply of safe drinking water has been one of the declared goals of the World H ealth Organization since its inception. This article quantifies these needs and describes the various attempts that have been made to meet them.The Global Situation Access to safe drinking water and adequate sanita tion is a recognised universal human need. However, in 1994 approximately 1.11 billion people in developing countries lacked access to safe water supply and 2.87 billion lacked access to adeq uate sanitation . On a global basis, i.e. including developed countries and countries in economic transition, 20 per cent of the world's population lacked safe water supply and 50 per cent had no adequate sanitation. Projections for the year 2000 show a reduction of those without safe water supply to 0. 75 billion, but an increase of those deprived of adequate sanitation to 3.31 billion (WHO, 1996a). Thus, the progress achieved on sanitation during the International Drinking-Water Supply and Sanitation Decade 1981-1990 will be largely dispelled by 2000.The Urban Challenge The growth of the megacities will become the biggest threat to health in th~ 21st century, with an estimated 61 per cent of the world's population livingin urban areas by 2025. United Nations statistics show that between 1950 and 1995 the number of cities in the industrialised world with a population above one million more than doubled, while their number in developing countries increased sixfold from 34 to 2 13. Statistics for 1994 show that 83.6 per cent of the urban population in developing countries had access to safe water supply, whereas sanitation services were provided to only 68 .5 per cent of the urban population . This demonstrates how sanitation has lagged behind, and how piped water to the house has been a more attractive option than a sewerage line carrying away the wastes. One of the major challenges for the engineer today is the leakage of water supply pipes due to their age. There are striking examples of unaccounted-for waters reaching up to 60 per cent of the quantities which are distributed by the waterworks (Warner, 1996). A desirable, and with some effort also realistic, goal should be that all urban dwellers have access to at least a certain basic minimum amount of safe household water. Some experts consider 50 litres per capita per day as a fair enough long-term goal for the people living in suburban areas. This should allow for an acceptable quality of life and human dignity. However, in some parts of the world already 20 litres per capita per day of clean water would mean a substantial improvement whil st elsewhere 200 litres per capita per day may be deemed sufficient. The United Nations Conference on Environment and Development in Rio de Janeiro, June 1992, set as a target: 'by the year 2000, to have ensured that all urban residents have access to at least 40 litres per capita per day of safe water. . .' (UNCED, 1992). This already poses a formidable challenge to many city ~ater utilities in developing countries.The Disease Burden The health improvements of the past decades have contributed decisively to enhance human welfare, but muchWATER more remains to be done in the developing world. One simple statistic gives a se nse of the prevailing burden of disease : abo ut 12.4 million children under age five died in 1990, with about one third directly attributable to waterborne diarrhoeal diseases. Had those children faced the mortality risks of their peers in establi shed market economies , the number of deaths would have been cut by more than 90 per cent i.e., to 1. 1 million (The World Bank, 1993). In total, it is estimated that more than five million people die from waterrelated diseases due to unsafe drinking water, unclean domestic environments, and improper excreta disposal. At any . given time perhaps half the population of developing countries is suffering from water- related diseases of w hich diarrhoeal diseases, infec tion s with internal helminths, malaria, schistosomiasis and river blindness are the mo st widespread and dangerous. H owever, the morbidity and mortality rate of water-related diseases can be reduced by 26 to 78 per cent, depending on the nature of the disease, through the provision of safe drinking-water supply and adequate sanitation (Esry et al. , 1991). The eradication of the Guinea worm , as one striking example, is fo reseen by 2000.Water Resources in Crisis Water scarcity has become a reality in many countries in the arid and semiarid parts of the world , and variability from season to season m akes much of the water supply unavailable w hen it is most needed. This particularly affects the demands for irrigation water which account for as much as 87 per cent of the w ater consumed globally. Based on global runoff, the theoretical per capita water availability is estimated at 7,300 cubic metres per person per year (UN , 1997), which may see m like an adequate amount, but it was estimated at double this amount thirty years ago . In reality, for people in many parts of the world the actual amount available is much less. Water withdrawal at the global level was estimated at 3 ,700 cubic kilometres p er year in 1990 w hich , together with instream requirements, amounts to 54 per cent of the global runoff that is geographically and temporally accessible (Gleick, 1997). Scarcity may result from natural variation in ru noff or storage, an inability to deliver the water to where it is needed, or increasing demands that can simply not be supported in a su stainable manner from existing resources. Not only are population and demand increasing, but pollution is reducing the useability for high-quality purpo ses such as domestic water supply.Global Water SupplyGlobal SanitationCoverage perspectives to 2000Coverage pers pecti ves to 20004.5 4 3.54.133.313.5 2.873.272.62.52.49 2.51.511.581.571.51.5 0.50.5 0 199019942000Groundwater supplies are coming under increasing pressure from growing human populations that consume more and more wa ter, particularly for urban drinking-water supply and agricultural irrigatio n . One res ult is that many g1oundwater reserves are being overexploited, with water being abstracted fro m them at unsu stainable ra tes . T his leads to a redu ction in groundwa ter in permanent storage and is sometimes called groundwater mining. In som e countries, fossil gro undwaters are being deliberately mined in attempts to speed the ra te of development or to reduce costs of fo od imports. H owever, the non-renewable portion , once used , is gone forever.Drinking Water Quality Production of po table water is often turning into a challenging task du e to natural or anthropogenic problem s with its quali ty. T here ca n be natural defi cien cy of esse ntial elem ents. Perhaps the most important elementdefi cien cy problem associate d with drinking wa ter is that of endemic goitre and cretinism , both of w hich are linked to dietary iodine defi ciency. It is estimated that up to one billion people globally are at ri sk fro m iodinedefi ciency disorders with some 200 to 300 million with manifest conditions . For other elem ents, there is only a narrow range of concentrations in water w ithin w hi ch b enefi cial effects are fo und. Excess of flu o ride (above about 1.5 milligram s per litre) leads to dental tluorosis and skeletal fluoro sis at higher levels. T he Rift Valley in Africa, parts of India and parts of C hina are places w here millions of people are suffering from these health effects. On the other hand , fluorid e levels below 0. 5 milligram s per litre pose the risk of dental caries which has to be compensated for by drinking-water fluo ridation or other therapeutic treatments. Arse nic is a toxic and carcinogenic element w hich is sometimes naturally present in water. There are areas with very high concentrations with well-documented cases of chronic arsenic poisoning su ch as in southern T aiwan , C hile, M exico , C hina and W est Bengal, India. The overriding priority problem ,199019942000however, remains. Infectious diseases are still transmitted by contaminated d ri nking wa ter, thro ugh inade quate sanitary disposal of human excreta, lack of personal hygiene, poor food preparation and handling practices, or insufficient quantities of wa ter for do mestic purposes. T he cholera epidemic that began in Peru in 199 1 and spread to 16 o ther countries in Latin America is the m ost striking demonstration in recent history of the intrinsic interdependence of safe drinki ng wa ter, human health and economic development. In Peru , w here the o utbreak was mos t seve re, the abrupt halt of touri sm and agricultural exports cost the Peruvian economy one billion U S dollars in j ust ten weeks. T he to tal economic cost ,to Peru was m ore than three times the total national dollar investment in wa ter supply and sa nitation improvements during the decade of the 1980s (The W orld Bank, 1992) . W aterborne infec tious diseases are no t a saddening privilege of the South, as the outbreak of cryptosporidiosis in Milwa ukee vividly demonstra ted in 1993. More than 400 ,000 people were affected. The m agnitude of this outbreak , unp recedented in the recent history of indu strialised countries, and its association with a municipal water treatment plant that fulfilled existing operational and public health regulations, sent a shock wave throughout the wa ter supply sector in many countries.Health Risk Assessment A comprehensive set of health-based criteria has been developed by WHO in the fo rm of Guidelines for DrinkingW ater Quality (WHO , 1993) . T hey are based on a broad international consensus on the assessment of the risks to human health fro m the presence of microbial agents and chemi cal sub stan ces in drinking water. An authoritative scientific basis was crea ted through more than 200 leading scientists from about 40 countries participating actively in the process. Subse quently, WHO initiated a progra m to tra nslate these guidelines into regulato ry action an d actual improvement of drinking-water safety at the local level. At the sam e time, the WATER SEPTEMBER/ OCTOBER 199711WATER quantitative assessm ent of the health risk from microbiological contamination of Hea lth 8 • Optimal J ictn dv chLo:e / Risks 7 drinking water so that Range / a comparison can be 6 made with potential DMF ( ro" h re; ard , tion 5 ch emical risk from I chlorination by-products. i\ 4 \ D ntal c ries In their pioneering ThJvroi ch, noes / 3 \ work, Regli et al. 2 (1993) concluded in "n., ,e l - · · ' / 't:ri mlin ~ flu rosi "relation to disinfection by-products (DBPs) F(, 1g/I) Dental fl 1oro is that: -----------1.5 4 10'0 125 7 30 60 0.5 0 • the risk of dea th from pathogens is at need for continuous reconsideration, least 100 to 1000 times greater than the amendment and revision was recognised. risk of cancer from DBPs Consequently, a continuing process of • the risk of illness fro m pathogens is at updating (or 'rolling revision') of the least 10,000 to one million times greater WHO Guidelines for Drinking-Water than the risk of ca ncer from DBP s Quality was se t in motion, w ith a • morbidity and mortality rates from number of chemical sub stan ces and pathogen s, compared with those from mi crobiological age nts subj ect to DBPs, may be considerably higher in periodic evaluation. Addenda will be developing countries w here the sanitary issued that contain evaluations of new and health statu s is not as good or already-evaluated substances/agents • in societies w here infant mortality for w hich new scientific information rates are high and life expectancy is low, has become available (WHO, 1996) . many people would not be expected to live long enough to incur cancer, w hich Health Benefits also ca uses much higher differences in One of the maj or achievements of risk resulting from expo sure to this century is t
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