Environmental Health Engineering in the Tropics: Water, Sanitation and Disease Control (Earthscan Water Text)

This fully updated third edition of the classic text, widely cited as the most important and useful book for health engineering and disease prevention, describes infectious diseases in tropical and developing countries, and the effective measures that may be used against them. The infections described include the diarrhoeal diseases, the common gut worms, Guinea worm, schistosomiasis, malaria, Bancroftian filariasis and other mosquito-borne infections. The environmental interventions that receive most attention are domestic water supplies and improved excreta disposal. Appropriate technology for these interventions, and also their impact on infectious diseases, are documented in detail. This third edition includes new sections on arsenic in groundwater supplies and arsenic removal technologies, and new material in most chapters, including water supplies in developing countries and surface water drainage. Cover Half Title Series Information Title Page Copyright Page Table of contents Preface to the first edition Preface to the second edition Preface to the third edition Acknowledgements Part I Health and pollution Chapter 1 Engineering and infectious disease 1.1 Introduction 1.2 Water-related infections Classification of transmission mechanisms 1. Water-borne route 2. Water-washed route 3. Water-based route 4. Insect vector route Classification of infections I. Faecal–oral diseases (non-bacterial) 1.3 Excreta-related infections Latency and persistence Conclusions 1.4 Refuse-related infections 1.5 Housing-related infections 1.6 Public and domestic domains 1.7 Summary 1.8 References 1.9 Further reading Chapter 2 Health and water chemistry 2.1 Introduction 2.2 The absence of necessary chemicals 2.3 Harmful organics Environmental pollution by the oil industry 2.4 Harmful inorganics 2.5 References 2.6 Further reading Chapter 3 Water quality and standards 3.1 Drinking water quality Microbiological characteristics Microbiological tests Microbiological standards Chemical and physical characteristics 3.2 Wastewater quality Introduction Suspended solids Oxygen demand Pathogenic micro-organisms Toxic chemicals Effluent quality and disposal 3.3 Industrial wastes The problem Control 3.4 Bathing water quality 3.5 Irrigation water quality 3.6 Water quality and fish 3.7 Water quality standards and QMRA 3.8 References 3.9 Further reading Part II Water supply Chapter 4 Water supplies in low and middle income countries 4.1 The haves and the have nots 4.2 Operation and maintenance 4.3 Appropriate technology 4.4 Benefits Production Health Time and energy savings, and their money value 4.5 Cost recovery and the private sector 4.6 Rural supplies and self-help 4.7 Self-supply 4.8 Hygiene promotion 4.9 Evaluation 4.10 Climate change and integrated water resource management 4.11 References 4.12 Further reading Chapter 5 Rural water supply 5.1 Breakdowns and technology Design for maintenance 5.2 Sources of water Protected springs Wells Pollution of wells and boreholes Well disinfection 5.3 Raising water Hand power Natural sources of power Motor pumps 5.4 Storage 5.5 Treatment in a rural context Storage Sedimentation Filtration and chlorination Removal of minerals and salts Household water treatment 5.6 Water distribution Individual connections Public water points 5.7 References 5.8 Further reading Chapter 6 Urban water supply and water treatment 6.1 Introduction 6.2 Coagulation and sedimentation Fluoride and arsenic removal 6.3 Filtration 6.4 Disinfection Chlorine demand Free residuals Combined residuals The breakpoint Chlorine dose Control of the dose Testing for chlorine Sources of chlorine The application of chlorine 6.5 Distribution 6.6 Water demand management Tariff policy Water-saving taps and fittings Consumer education and information 6.7 References 6.8 Further reading Part III Excreta and refuse Chapter 7 Excreta disposal in low and middle income countries 7.1 The haves and have nots 7.2 The evolving agenda of sanitation for the poor 7.3 Cities and the need for hygienic management of faecal sludge 7.4 Relative costs of sanitation systems Subsidy 7.5 References 7.6 Further reading Chapter 8 Types of excreta disposal system 8.1 Introduction 8.2 Pit latrines 8.3 VIP latrines 8.4 Difficulties with pit latrines Flooding Rocky ground Sand Water contamination Nitrate accumulation 8.5 Pour-flush toilets 8.6 Vault toilets and cartage 8.7 Septic tanks 8.8 Small-bore sewers Simplified sewerage 8.9 Other systems Bucket latrines, and their renaissance as container-based sanitation Aqua privies Cesspools Compost toilet 8.10 Communal latrines 8.11 Soil conditions 8.12 Soakaway designs 8.13 Personal hygiene 8.14 Sullage disposal 8.15 Nightsoil and sludge re-use and disposal Agriculture Aquaculture Energy Disposal 8.16 Water availability 8.17 References 8.18 Further reading Chapter 9 Planning a sanitation programme 9.1 Programme context and content Context Content 9.2 Sanitation marketing The four Ps of marketing Product Price Place Promotion The process of sanitation marketing 1) Win consensus 2) Learn about the market 3) Overcome barriers, promote demand 4) Develop the right products 5) Develop a thriving industry 6) Regulate waste transport and final disposal 9.3 Choice of system 9.4 Social factors The extension system 9.5 Costs Economic costs Financial costs 9.6 Operation and maintenance 9.7 Incremental sanitation 9.8 References 9.9 Further reading Chapter 10 Wastewater treatment 10.1 Introduction 10.2 Waste characteristics 10.3 Waste stabilisation ponds Anaerobic ponds Facultative ponds Maturation ponds High-rate ponds Bacterial reduction Helminth egg removal Location Design features Pre-treatment Pond maintenance Troubleshooting and remedial measures 10.4 Aerated lagoons 10.5 Oxidation ditches 10.6 Pathogen removal 10.7 Sewage workers’ health 10.8 References 10.9 Further reading Chapter 11 Surface water drainage 11.1 Introduction 11.2 Town planning implications 11.3 Technical aspects Resources Objectives Channels Sediment Solid waste management and maintenance Realistic enforcement Organisation 11.4 Institutional aspects 11.5 References 11.6 Further reading Chapter 12 Solid waste management 12.1 Introduction 12.2 Waste characteristics 12.3 Hazards of refuse mismanagement 12.4 Storage and collection Vehicles and transfer 12.5 Treatment and disposal Sanitary landfill Incineration Composting Choice of method 12.6 References 12.7 Further reading Chapter 13 Composting 13.1 Aerobic and anaerobic composting 13.2 Techniques Forced aeration 13.3 Carbon/nitrogen.ratio 13.4 Problems of composting 13.5 Individual composting toilets 13.6 References 13.7 Further reading Chapter 14 Health aspects of waste use 14.1 Introduction 14.2 Health and agricultural use 14.3 Health and fish farming 1) Passive transference of pathogens by fish 2) Transmission of helminths 3) The risk to fishery workers of schistosomiasis 14.4 References 14.5 Further reading Part IV Environmental modifications and vector-borne diseases Chapter 15 Engineering control of insect-borne diseases 15.1 Introduction 15.2 Mosquito-borne diseases Malaria 1) Chemotherapy of infected people 2) Killing of adult mosquitoes 3) Treatment or elimination of breeding sites Filariasis Yellow fever, dengue and other arboviruses 15.3 Fly-borne diseases Sleeping sickness Onchocerciasis Leishmaniasis Loiasis Mechanical transmission 15.4 Chagas disease and bugs 15.5 Lice, fleas, ticks and mites 15.6 Conclusions 15.7 References 15.8 Further reading Chapter 16 Dams, irrigation and health 16.1 General considerations Planning for health The construction phase Displaced persons Agricultural workers Changes in the local ecosystem which affect disease patterns 16.2 Onchocerciasis 16.3 Malaria 16.4 Arboviral infections 16.5 Bancroftian and Malayan filariasis 16.6 Spillways and reservoir release policies Onchocerciasis and reservoir release Siphon spillways 16.7 References 16.8 Further reading Chapter 17 Schistosomiasis 17.1 Introduction 17.2 Water supply and sanitation Water supply Excreta disposal 17.3 Schistosome removal from water and wastes Cercariae in water treatment Eggs and miracidia in sewage treatment 17.4 Specific engineering and environmental methods in schistosomiasis control Reduction of human–water contact Appropriate channel design Drainage Irrigation practices Barriers Level fluctuations Assistance to chemical control of snails Miscellaneous measures 17.5 References 17.6 Further reading Appendix A: Biological classification conventions Appendix B: Glossary Appendix C: Checklist of water-related and excreta-related diseases Appendix D: A brief primer on urban mosquito control Appendix E: Units Index