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Viruses and wastewater treatment
Book Reviews scribed; wherever possible, as with phenols, colorimetric methods are also given. Apart from the measurement of primary production, chlorophyll a and dissolved methane, all clearly of importance in lake studies, references to biological methods of examining waters are absent from the manual. The methods given are clearly and uniformly presented by succinctly describing the occurrence of the determinand, the principle of the method of examination and its application, the reagents and equipment required, the procedure to be followed, and the calculation of the results, with a few literature references. In printing, lay out and binding the publication is almost identical with the German "Einheitsverfahrln" with which the reviewer has been familiar for the last 25 years. It is likely to stand the test of time just as successfully as its progenitor. S. H. JENKINS
Water Reuse Symposium II: Proceedings of a Conference. AWWA Research Foundation, Denver, CO, 1981. Volumes 1, 2 and 3. $30 The theme of this conference, "Water Reuse in the Future" has led to the publication of 165 papers reviewing the present position on the reclamation of municipal wastewater throughout the world, the reuse of water in agriculture, the food and other industries, the treatment of wastewater necessary to make reclamation possible, the health risks that require to be evaluated in water reuse and the monitoring of the reclaimed water quality and the future outlook for water reuse. If any doubts still remain that wastewater will be reused on a massive scale in the future, the papers described in these three volumes will soon dispel them. For not only are there accounts of the planned reuse of water in Israel, Saudi Arabia, South Africa and Hong Kong, to name but a few examples of many, but numerous other state-of-thearts papers describe how, with suitable safeguards, recycling of water that would otherwise be wasted is providing an acceptable substitute for landscape irrigation, groundwater recharge, aquaculture and an extremely wide range of industrial processes. The two important economic factors which have led water suppliers to turn to the reuse of wastewater are the increasing costs of obtaining new sources of unpolluted water and the absence of adequate water supplies in developing areas. The growing confidence in scientific monitoring techniques to provide surveillance which will ensure the safety of reclaimed water and the ability of modern water treatment processes to meet stringent health and reuse criteria are added incentives to pursue policies of extending the areas of water reuse. The papers on policy matters are of interest in showing the importance that should be attached to the coordination of research, development, technical aspects and results of reuse as well as public attitudes towards reclaimed soiled water. Since the indirect use of such water has gained public acceptance for years, mere extension of this policy will meet with little resistance and this is likely to be the general line that will be followed in the future. Although it has been proved on a large scale that sewage effluent can safely be converted into drinking water fit for direct use, commonsense suggests that this will be the rare exception rather than the rule. However, one of the most reassuring features of the subject of water reuse, which is well brought out in the proceedings of this conference, is the critical scrutiny to which reused water is being subjected from the point of view of microbiological and chemical health risks and its suitability for a variety of purposes. The papers do not appear to have been adequately edited before publication and the assembly of all tables and
479
diagrams at the end of many of the papers hardly facilitates ready understanding of the text. Nevertheless, judged on their collective, rather than their individual merit, the papers make a significant contribution to the advancement of the subject of water reuse. The modest cost of three volumes of papers running to over 2500 pages of $30 which includes postage is an indication of generous financial support which the conference organizers must have received, a move which other countries might well be encouraged to follow. S. H. JENKINS Viruses and Wastewater Treatment, edited by M. Goddard and M. Butler. Pergamon Press, Oxford. 1981, 306 pp., £25.00.
The ever increasing demand for high quality water for industrial use and for human consumption has lead to an awareness of the possible threat to public health of recycling wastewater. The major concern in the last few years has been the recognition that large numbers of viruses enter water courses and are present at abstraction points for potable supply. In September 1980, an international symposium was held at the University of Surrey, Guildford, U.K., to discuss the implications of virus presence in wastewater. The conference, attended by many of the world's active water virologists, reviewed the incidence of viruses in wastewater, examined their behaviour during treatment, investigated virus-particulate association. assessed the methodology available to conduct virological analyses and questioned the evidence for the role of water in the epidemiology of viral disease. The book is presented in the same format as the conference with key papers reviewing a major aspect and shorter papers providing data on experimental findings. The first part of the proceedings is dedicated to establishing the types of viruses and levels which are excreted in human faeces and their survival into the sewage system. The contribution by Banatvala detailing faecally-excreted virus is well-illustrated with electron micrographs and serves as a useful introduction to water virology. The effect of treatment processes is reviewed by Gerba who, apart from summarising the removal efficiency of individual processes, introduces interesting data on rotaviruses suggesting that current treatment methods remove these less efficiently than other enteroviruses. Sludge treatment and its usefulness in reducing viral levels is reviewed by Ward who emphasised that viral destruction can only be achieved by use of procedures designed to overcome the protection afforded by virus-particulate association. Composting of sludge, with its attendant self-generated high temperatures, is particularly effective for virus inactivation. Virus survival in receiving waters is dependent on many factors (Sattar) with temperature and pH being the most important. Attention is drawn to the fact that our understanding of viral survival is still very rudimentary. A large amount of wastewater is disposed to land and the survival of viruses in soil is reviewed by Wellings. The degree of association with particulates seems to be dependent on virus type and soil type with clays binding effectively with viruses whereas the association is minimal with sandy soils. The problem and implications of sequential adsorption and desorption of viruses resulting in movement through soil are briefly discussed. Disinfection of effluents, a common practice in some parts of the world, is reviewed byButler. It is stressed that careful control of the process is required if dissemination of harmful byproducts is to be minimised. The association of viruses with particulate material is of special importance as a degree of protection is afforded by such an arrangement especially when disinfection is being carried out. Lund examined the methodology available to
4X()
Book Re~ic~s
assess the degree of relationship with the observation that no method is presently entirely satisfactory. The mechanism of virus solid association was briefly reported by Stotzky and colleagues with the cation exchange capacity and ratio of the number of negatively- to positivelycharged sites on clays being important. Methods for recovering viruses from large volumes of water wcrc reviewed by Primrose and colleagues with a recommendation that positively-charged filters used in the adsorption-elution procedure offering best returns with Sobsey and Glass contirming such findings. Data presented, however, does suggest that substantial variation of recover) cfficiencies occurs when comparing viral serotypes. It has been the practice to use bacteria as indicative of faecal pollution and synonymously of viral pollution. Morris and Waite questioned the rationale behind this and concluded that direct detection of viruses is the only valid way of determining the degree of viral contamination. The problems associated with shellfish rearing m polluted waters is reported by Appleton with the observation that incorrect cooking was probably responsible for viral gastroenteritis. Studies in the US and Egypt provided some insights as to the aetiology of the observed swimming-associated, pollution-related gastroenteritis. The gastroenteric viruses described earlier in the book are implicated in such incidents, particularly rotavirus (Cabelli). An important observation is that at the onset of the epidemiological programme it was thought that swimming in sewage polluted waters would be a relatively minor routine of transmission but this does not seem to be the case. Infection is not so much age-related but whether or not the individual is a swimmer. The proceedings have a wider range than the title implies but nevertheless they form a most useful source book which is certainly a requirement for any laboratory where the importance of viral contamination of the environment is being studied. It is also of use to clinical virologists who may not fully appreciate the problems encountered when ensuring that disease dissemination by the water route does not occur. R. MORRIS
Water & Wastewater E ~ e e r i n g Systems, by D. Barnes, P. J. Bliss, B. W. Gould and H. R. Vallentine. Pitman, London, 1981. xvi + 513pp. £10.95 (Paperback). £17.50 (Hard cover). With the advent of multifunctional water authorities in England and Wales, and the trend towards integrated river basin m a n a g e m e n t in other countries, it is inevitable, and very desirable, that the old distinctions between specialists in "clean water" and "dirty water" should begin to disappear. This volume is a multi-disciplinary text book dealing with a large part of the water cycle, from the acquisition of water for public supply to the ultimate disposal of sludges. A m o n g the subjects discussed are water treatment, waste water treatment and pollution of the environment. The word "'engineering" in the title perhaps makes the book seem more restricted in scope than it is- -it covers chemical and microbiological, in addition to engineering aspects. In such a wide-ranging volume it could hardly be expected that any subject would be dealt with in great detail. Nevertheless, the authors have been able to include a great deal of statistical and mathematical material, which indeed is necessary if justice is to be done to the 90 or so numerical problems in the appendix. In their preface the authors stress that the book is not a manual for practising engineers. It is designed as an introductory text for 3rd year civil engineering students having a background knowledge of physics, chemistry and mathematics. Though based on a course at the University of
New South Wales the book is of international applicat)on and uses metric units throughoul. No references are given in the text but a list of textbooks is included for those readers who wish lo pur~nc Iheil interests in greater detail. Within its self-imposed limitations, the book is hard to fault. Rather surprisingly, there is no mention of the design of sea outfulls; recent work on the use of oxygen in rising main sewers does not seem to have come to lhe authors" attention : aim though the important matter of nitrification in the BOD test is discussed, there is no mention of the simple and widely-accepted method of suppressing nitrilication using allylthiourea. There are relatively minor omissions which do not detract greatly from the value of a most interesting book. All engineers and scientists concerned with water will find material here to widen their horizons. G. E. EDEN
Technical and Economic Options. Volume 1 in the Series Appropriate Technology for Water Supply and Sanitation, The World Bank, Washington, DC, 1980, 116 p p , by John M. Kalbermatten, DeAnne S. Julius and Charles C. Gunnerson. During the past 4 or 5 years the World Bank has'played a major role in arousing interest in sanitation, which is an essential but too-often-neglected component of the International Drinking Water Supply and Sanitation Decade. Working with U N D P and other organizations the Bank has examined a variety of sanitation options and the interaction of sanitation with technology, health, economics and socio-cultural conditions. On the bases of these studies they are issuing a number of volumes, of which Technical and economic options is the first to be published by the Bank itself. Two-thirds of the document is devoted to analysis of studies carried out in a number of developing countries or by experts in particular fields (such as health) based on world-wide evidence. It is therefore in a way a s u m m a r y of other volumes in the series which look at particular aspects in detail. It is very useful for technologists and economists involved, or likely to be involved, in Third World sanltauon. It is also a valuable exposition of the "state of the art" which should interest a wide readership. The "'art" is rapidly changing because low-cost sanitation is now receiving so much attention The analysis of field results is dealt with in four chapters covering the technical and enwronmental assessment. economic comparison, public health aspects and socto economic factors. The second and short part of the book gives recommendations for program planning and development under the headings of implementation of appropriate sanitation, technology, institutional requirements, community participation and organization and project development. There is some repetition and the book shows evidence of a large number of contributors. One notion which appears several times cannot be repeated too often, because administrators, politicians and professionals alike seem conditioned to ignore it. It is that a conventional sewerage and sewage treatment system is a completely appropriate form of sanitation technology in certain circumstances, but because of the cost. wasteful water use and environmental hazards it is not suitable ['or widespread adoption. The assumption that sewerage provides the best public health protection is refuted by examples of pathogen reduction. Of these the most startling is that conventionally treated effluent may contain ID 11 cholera vib~rio per day from a single infected person.
Water Reuse Symposium II: Proceedings of a Conference. AWWA Research Foundation, Denver, CO, 1981. Volumes 1, 2 and 3. $30 The theme of this conference, "Water Reuse in the Future" has led to the publication of 165 papers reviewing the present position on the reclamation of municipal wastewater throughout the world, the reuse of water in agriculture, the food and other industries, the treatment of wastewater necessary to make reclamation possible, the health risks that require to be evaluated in water reuse and the monitoring of the reclaimed water quality and the future outlook for water reuse. If any doubts still remain that wastewater will be reused on a massive scale in the future, the papers described in these three volumes will soon dispel them. For not only are there accounts of the planned reuse of water in Israel, Saudi Arabia, South Africa and Hong Kong, to name but a few examples of many, but numerous other state-of-thearts papers describe how, with suitable safeguards, recycling of water that would otherwise be wasted is providing an acceptable substitute for landscape irrigation, groundwater recharge, aquaculture and an extremely wide range of industrial processes. The two important economic factors which have led water suppliers to turn to the reuse of wastewater are the increasing costs of obtaining new sources of unpolluted water and the absence of adequate water supplies in developing areas. The growing confidence in scientific monitoring techniques to provide surveillance which will ensure the safety of reclaimed water and the ability of modern water treatment processes to meet stringent health and reuse criteria are added incentives to pursue policies of extending the areas of water reuse. The papers on policy matters are of interest in showing the importance that should be attached to the coordination of research, development, technical aspects and results of reuse as well as public attitudes towards reclaimed soiled water. Since the indirect use of such water has gained public acceptance for years, mere extension of this policy will meet with little resistance and this is likely to be the general line that will be followed in the future. Although it has been proved on a large scale that sewage effluent can safely be converted into drinking water fit for direct use, commonsense suggests that this will be the rare exception rather than the rule. However, one of the most reassuring features of the subject of water reuse, which is well brought out in the proceedings of this conference, is the critical scrutiny to which reused water is being subjected from the point of view of microbiological and chemical health risks and its suitability for a variety of purposes. The papers do not appear to have been adequately edited before publication and the assembly of all tables and
479
diagrams at the end of many of the papers hardly facilitates ready understanding of the text. Nevertheless, judged on their collective, rather than their individual merit, the papers make a significant contribution to the advancement of the subject of water reuse. The modest cost of three volumes of papers running to over 2500 pages of $30 which includes postage is an indication of generous financial support which the conference organizers must have received, a move which other countries might well be encouraged to follow. S. H. JENKINS Viruses and Wastewater Treatment, edited by M. Goddard and M. Butler. Pergamon Press, Oxford. 1981, 306 pp., £25.00.
The ever increasing demand for high quality water for industrial use and for human consumption has lead to an awareness of the possible threat to public health of recycling wastewater. The major concern in the last few years has been the recognition that large numbers of viruses enter water courses and are present at abstraction points for potable supply. In September 1980, an international symposium was held at the University of Surrey, Guildford, U.K., to discuss the implications of virus presence in wastewater. The conference, attended by many of the world's active water virologists, reviewed the incidence of viruses in wastewater, examined their behaviour during treatment, investigated virus-particulate association. assessed the methodology available to conduct virological analyses and questioned the evidence for the role of water in the epidemiology of viral disease. The book is presented in the same format as the conference with key papers reviewing a major aspect and shorter papers providing data on experimental findings. The first part of the proceedings is dedicated to establishing the types of viruses and levels which are excreted in human faeces and their survival into the sewage system. The contribution by Banatvala detailing faecally-excreted virus is well-illustrated with electron micrographs and serves as a useful introduction to water virology. The effect of treatment processes is reviewed by Gerba who, apart from summarising the removal efficiency of individual processes, introduces interesting data on rotaviruses suggesting that current treatment methods remove these less efficiently than other enteroviruses. Sludge treatment and its usefulness in reducing viral levels is reviewed by Ward who emphasised that viral destruction can only be achieved by use of procedures designed to overcome the protection afforded by virus-particulate association. Composting of sludge, with its attendant self-generated high temperatures, is particularly effective for virus inactivation. Virus survival in receiving waters is dependent on many factors (Sattar) with temperature and pH being the most important. Attention is drawn to the fact that our understanding of viral survival is still very rudimentary. A large amount of wastewater is disposed to land and the survival of viruses in soil is reviewed by Wellings. The degree of association with particulates seems to be dependent on virus type and soil type with clays binding effectively with viruses whereas the association is minimal with sandy soils. The problem and implications of sequential adsorption and desorption of viruses resulting in movement through soil are briefly discussed. Disinfection of effluents, a common practice in some parts of the world, is reviewed byButler. It is stressed that careful control of the process is required if dissemination of harmful byproducts is to be minimised. The association of viruses with particulate material is of special importance as a degree of protection is afforded by such an arrangement especially when disinfection is being carried out. Lund examined the methodology available to
4X()
Book Re~ic~s
assess the degree of relationship with the observation that no method is presently entirely satisfactory. The mechanism of virus solid association was briefly reported by Stotzky and colleagues with the cation exchange capacity and ratio of the number of negatively- to positivelycharged sites on clays being important. Methods for recovering viruses from large volumes of water wcrc reviewed by Primrose and colleagues with a recommendation that positively-charged filters used in the adsorption-elution procedure offering best returns with Sobsey and Glass contirming such findings. Data presented, however, does suggest that substantial variation of recover) cfficiencies occurs when comparing viral serotypes. It has been the practice to use bacteria as indicative of faecal pollution and synonymously of viral pollution. Morris and Waite questioned the rationale behind this and concluded that direct detection of viruses is the only valid way of determining the degree of viral contamination. The problems associated with shellfish rearing m polluted waters is reported by Appleton with the observation that incorrect cooking was probably responsible for viral gastroenteritis. Studies in the US and Egypt provided some insights as to the aetiology of the observed swimming-associated, pollution-related gastroenteritis. The gastroenteric viruses described earlier in the book are implicated in such incidents, particularly rotavirus (Cabelli). An important observation is that at the onset of the epidemiological programme it was thought that swimming in sewage polluted waters would be a relatively minor routine of transmission but this does not seem to be the case. Infection is not so much age-related but whether or not the individual is a swimmer. The proceedings have a wider range than the title implies but nevertheless they form a most useful source book which is certainly a requirement for any laboratory where the importance of viral contamination of the environment is being studied. It is also of use to clinical virologists who may not fully appreciate the problems encountered when ensuring that disease dissemination by the water route does not occur. R. MORRIS
Water & Wastewater E ~ e e r i n g Systems, by D. Barnes, P. J. Bliss, B. W. Gould and H. R. Vallentine. Pitman, London, 1981. xvi + 513pp. £10.95 (Paperback). £17.50 (Hard cover). With the advent of multifunctional water authorities in England and Wales, and the trend towards integrated river basin m a n a g e m e n t in other countries, it is inevitable, and very desirable, that the old distinctions between specialists in "clean water" and "dirty water" should begin to disappear. This volume is a multi-disciplinary text book dealing with a large part of the water cycle, from the acquisition of water for public supply to the ultimate disposal of sludges. A m o n g the subjects discussed are water treatment, waste water treatment and pollution of the environment. The word "'engineering" in the title perhaps makes the book seem more restricted in scope than it is- -it covers chemical and microbiological, in addition to engineering aspects. In such a wide-ranging volume it could hardly be expected that any subject would be dealt with in great detail. Nevertheless, the authors have been able to include a great deal of statistical and mathematical material, which indeed is necessary if justice is to be done to the 90 or so numerical problems in the appendix. In their preface the authors stress that the book is not a manual for practising engineers. It is designed as an introductory text for 3rd year civil engineering students having a background knowledge of physics, chemistry and mathematics. Though based on a course at the University of
New South Wales the book is of international applicat)on and uses metric units throughoul. No references are given in the text but a list of textbooks is included for those readers who wish lo pur~nc Iheil interests in greater detail. Within its self-imposed limitations, the book is hard to fault. Rather surprisingly, there is no mention of the design of sea outfulls; recent work on the use of oxygen in rising main sewers does not seem to have come to lhe authors" attention : aim though the important matter of nitrification in the BOD test is discussed, there is no mention of the simple and widely-accepted method of suppressing nitrilication using allylthiourea. There are relatively minor omissions which do not detract greatly from the value of a most interesting book. All engineers and scientists concerned with water will find material here to widen their horizons. G. E. EDEN
Technical and Economic Options. Volume 1 in the Series Appropriate Technology for Water Supply and Sanitation, The World Bank, Washington, DC, 1980, 116 p p , by John M. Kalbermatten, DeAnne S. Julius and Charles C. Gunnerson. During the past 4 or 5 years the World Bank has'played a major role in arousing interest in sanitation, which is an essential but too-often-neglected component of the International Drinking Water Supply and Sanitation Decade. Working with U N D P and other organizations the Bank has examined a variety of sanitation options and the interaction of sanitation with technology, health, economics and socio-cultural conditions. On the bases of these studies they are issuing a number of volumes, of which Technical and economic options is the first to be published by the Bank itself. Two-thirds of the document is devoted to analysis of studies carried out in a number of developing countries or by experts in particular fields (such as health) based on world-wide evidence. It is therefore in a way a s u m m a r y of other volumes in the series which look at particular aspects in detail. It is very useful for technologists and economists involved, or likely to be involved, in Third World sanltauon. It is also a valuable exposition of the "state of the art" which should interest a wide readership. The "'art" is rapidly changing because low-cost sanitation is now receiving so much attention The analysis of field results is dealt with in four chapters covering the technical and enwronmental assessment. economic comparison, public health aspects and socto economic factors. The second and short part of the book gives recommendations for program planning and development under the headings of implementation of appropriate sanitation, technology, institutional requirements, community participation and organization and project development. There is some repetition and the book shows evidence of a large number of contributors. One notion which appears several times cannot be repeated too often, because administrators, politicians and professionals alike seem conditioned to ignore it. It is that a conventional sewerage and sewage treatment system is a completely appropriate form of sanitation technology in certain circumstances, but because of the cost. wasteful water use and environmental hazards it is not suitable ['or widespread adoption. The assumption that sewerage provides the best public health protection is refuted by examples of pathogen reduction. Of these the most startling is that conventionally treated effluent may contain ID 11 cholera vib~rio per day from a single infected person.