1st Edition

Urban Water Security: Managing Risks UNESCO-IHP

Edited By Blanca Jimenez Cisneros, Joan B. Rose Copyright 2009

    Understanding the impacts of urbanization on the urban water cycle and managing the associated health risks demand adequate strategies and measures. Health risks associated with urban water systems and services include the microbiological and chemical contamination of urban waters and outbreak of water-borne diseases, mainly due to poor water and sanitation in urban areas, and the discharge as well as the disposal of inadequately treated, or untreated, industrial and domestic wastewater. Climate change only exacerbates these problems, as alternative scenarios need to be taken into consideration in urban water risk management.

    Urban Water Security: Managing Risks – the result of a project by UNESCO’s International Hydrological Programme on the topic – addresses issues associated with urban water risks. The first section of the volume describes risks associated with urban water systems and services. The volume then discusses the concept of risk management for urban water systems and explores different approaches to managing and controlling urban water risks. A concluding section presents case studies on managing urban water risks.

    1 Introduction 

    2 Drinking water – Potential health effects caused by wastewater disposal 
    2.1 Introduction 
    2.2 Direct and indirect wastewater reuse 
    2.3 Microbiological risks 
    2.3.1 Viruses 
    2.3.2 Bacteria 
    2.3.3 Protozoa 
    2.3.4 Helminths 
    2.4 Risk reduction of pathogens in drinking water 
    2.5 Chemical risks 
    2.6 Treated wastewater in surface waters 
    2.7 The occurrence of pharmaceuticals in drinking water 
    2.8 Risk management of microbial and chemical hazards 
    2.9 Implementation of Water Safety Plans 
    2.10 HACCP 
    2.11 Hazard analysis 
    2.12 Conclusions 
    2.13 References 

    3 Microbial Health Risks and Water Quality 
    3.1 Introduction 
    3.2 The Traditional Icons of Waterborne Disease 
    3.2.1 Cholera 
    3.2.2 Typhoid 
    3.2.3 Hepatitis 
    3.2.4 Generic Diarrhea 
    3.3 Emerging Diseases and Zoonotic Pathogens 
    3.3.1 Cryptosporidium 
    3.3.2 Cyclospora 
    3.3.3 E. coli O157:H7 
    3.3.4 Helicobacter 
    3.4 Risk Assessment and Control of Waterborne Pathogens 
    3.4.1 Use of Quantitative Microbial Risk Assessment 
    3.4.2 Interventions to reduce enteric diseases
    3.4.3 Vaccinations 
    3.5 Conclusions and Recommendations 
    3.6 References 

    4 Chemical Health Risks 
    4.1 Introduction 
    4.2 Human Health Risks 
    4.2.1 An Overview on Exposure Factors 
    4.2.2 Human Exposure in Urban Water Cycle 
    4.3 Risk Sources and Risk Compounds in Urban Water Cycle 
    4.3.1 Releases to Water 
    4.3.2 Chemical Compounds 
    4.4 Inorganic Chemical Risk Agents: Sources and Human Health Diseases of Concern 
    4.4.1 Nitrates and Nitrites 
    4.4.2 Fluoride 
    4.4.3 Toxic Metals Arsenic Mercury Lead 
    4.5 Organic Chemical Risk Agents: Sources and Human Health Diseases of Concern 
    4.5.1 Hydrocarbons Compounds 
    4.5.2 Chlorinated Organic Compounds Volatile Organic Compounds (VOCs) Solvents Trihalomethanes (THMs) 
    4.5.3 Pesticides 
    4.5.4 Persistent Organic Pollutants (POPs) 
    4.5.5 New Chemicals 
    4.6 Chemical Risks in Urban Cities in Developed Countries 
    4.6.1 Fluoride China Japan United States of America 
    4.6.2 Arsenic (As) Canada China United States of America 
    4.6.3 Mercury Canada Arctic China Japan United States of America 
    4.6.4 Volatile Organic Compounds (VOCs) Netherlands United States of America 
    4.6.5 Trihalomethanes (THMs) Alaska Canada United Kingdom United States of America 
    4.6.6 New Chemicals 
    4.7 Chemical Risks in Urban Cities in Developing Countries 
    4.7.1 Fluoride Brazil Ethiopia India Kenya Mexico Saudi Arabia South Africa Turkey United Republic of Tanzania 
    4.7.2 Arsenic (As) Argentina Bangladesh – West Bengal, India Chile Mexico Taiwan Thailand Vietnam 
    4.7.3 Mercury (Hg) Brazil Philippines South Africa 
    4.7.4 Trihalomethanes (THMs) Greece Malaysia Mexico Turkey 
    4.7.5 Pesticides Brazil Egypt South Africa 
    4.8 Chemical Risk Management in Urban Water Cycle
    4.8.1 Chemical Risks Identification in Urban Water Cycle Drinking water Other water-related chemical risks 
    4.8.2 Vulnerability and Variability 
    4.8.3 Urban Water Policy 
    4.9 References 

    5 Risk Management on the urban water cycle. Climate change risks 
    5.1 Introduction 
    5.1.1 Global climate change 
    5.1.2 Global climate change and hydrological cycle 
    5.1.3 Mitigation of GHG emissions 
    5.2 Water in an urbanized world 
    5.2.1 Water scarcity 
    5.3 Impacts and risks 
    5.3.1 Water availability and glacial melt 
    5.3.2 Sea level rise and extreme events 
    5.3.3 Water quality 
    5.3.4 Changes in the past decades related to Global Climate Change 
    5.3.5 Risks for urban settlements 
    5.4 Adaptation and integration of climate change into urban water resource management 
    5.4.1 Adaptation and sustainable development
    5.4.2 Planning under uncertainties 
    5.4.3 Supply and demand options 
    5.4.4 Urban water management 
    5.4.5 Poverty and equity 
    5.4.6 International aid 
    5.5 Conclusions
    5.6 References 

    6 Water source and drinking water risk management 
    6.1 Introduction 
    6.2 Security, Reliability and Risk 
    6.3 Uncertainty, Threats and Effects 
    6.4 Prevention, Mitigation and Resolution 
    6.5 Scarcity and Drought, an Operational Example 
    6.6 Conclusions and Recommendations 

    7 Wastewater risks in the urban water cycle 
    7.1 Introduction 
    7.2 Pollutants sources 
    7.2.1 Point sources Municipal wastewater Industrial wastewater Stormwater 
    7.2.2 Non point pollutant sources Urban infrastructure Urban activities Disposal practices Other sources 
    7.3 Pollutants involved 
    7.3.1 Conventional parameters 
    7.3.2 Biological pollutants 
    7.3.3 Emerging pollutants Content in water Content in surface and groundwater 
    7.4 Management 
    7.4.1 Changing the concept of pollution sources 
    7.4.2 Gathering useful information 
    7.4.3 Monitoring campaigns
    7.4.4 Water Sources management Groundwater Surface water 
    7.4.5 Pollutant management Biological pollutants Chemical compounds 
    7.4.6 Urban infrastructure and urban activities 
    7.4.7 Climate change 
    7.4.8 Education and research 
    7.5 Treatment 
    7.5.1 Biological pollutants 
    7.5.2 Emerging pollutants 
    7.5.3 Criteria for selecting wastewater treatment processes 
    7.6 Wastewater disposal 
    7.6.1 Soil disposal Soil disposal and aquifer storage Soil disposal and agriculture 
    7.6.2 Disposal in water bodies Eutrophication Coupling wastewater disposal with water reuse 
    7.7 Conclusions 
    7.8 References 

    8 Risks Associated with Biosolids Reuse in Agriculture 
    8.1 Introduction 
    8.2 Nutrient and agronomic value 
    8.3 Microbiological quality 
    8.4 Potentially toxic elements 
    8.5 Organic contaminants 
    8.6 Conclusions 
    8.7 References

    9 “Closing the Urban Water Cycle” Integrated Approach towards Water Reuse in Windhoek, Namibia 
    9.1 Introduction 
    9.2 Water sources in Windhoek 
    9.2.1 Conventional water sources 
    9.3 Reuse Options Implemented in Windhoek 
    9.4 Future water supply augmentation to Windhoek 
    9.5 Various process modifications from 1968 to 1995 
    9.6 Process design for the new Goreangab water reclamation plant 
    9.6.1 Summary 
    9.6.2 Raw Water Quality Profile 
    9.6.3 Determination of Treatment Objectives 
    9.6.4 The Multiple-Barrier Concept 
    9.6.5 Experiments and Pilot Studies to Determine Process Design Criteria 
    9.7 Selection of Final Process Train 
    9.8 Operational Experience to Date 
    9.9 Water Quality and Monitoring 
    9.10 Quality concerns with the present process configuration 
    9.11 Cost Considerations 
    9.12 Public Acceptance of Direct Potable Reuse 
    9.13 New Research and Development Options 
    9.14 Conclusion 
    9.15 References 

    10 Reducing risk from wastewater use in urban farming – a case study of Accra, Ghana 
    10.1 Introduction 
    10.2 The case of Accra 
    10.2.1 Urban water use and wastewater management 
    10.2.2 Irrigated urban vegetable farming 
    10.2.3 Irrigation water quality 
    10.2.4 Quality of vegetables in urban markets in Accra 
    10.2.5 Numbers of consumers at risks
    10.2.6 Risk Assessment to farmers and consumers 
    10.3 Risk reduction measures 
    10.3.1 Explore alternative farmland, tenure security and safer water sources 
    10.3.2 Promote safer irrigation methods 
    10.3.3 Influence the choice of crops grown 
    10.3.4 Avoid post-harvest contamination 
    10.3.5 Assist post-harvest decontamination 
    10.3.6 Improve institutional coordination to develop integrated policies 
    10.4 Conclusions 
    10.5 References 

    11 Drinking water – potential health effects caused by infiltration of pollutants from solid waste landfills 
    11.1 Introduction 
    11.2 Pollutants in landfill leachates 
    11.3 The exposure pathways and mechanisms 
    11.4 Cases 
    11.5 Conclusions 
    11.6 References 

    12 Exploding sewers: the industrial use and abuse of municipal sewers, and reducing the risk—the experience of Louisville, Kentucky US 
    12.1 Introduction 
    12.2 The Hexa-Octa Incident 
    12.3 The sewer explosions 
    12.4 Industrial waste and hazardous spills 
    12.5 About the Louisville and Jefferson County Metropolitan Sewer District (MSD) 
    12.6 Reasons for doing permitting and pretreatment compliance programs 
    12.7 Components of the Permitting and Pretreatment Compliance Program 
    12.7.1 Commercial/industrial process plan review 
    12.7.2 Permits 
    12.7.3 Unusual Discharge Requests (UDR) 
    12.7.4 Industrial inspections 
    12.7.5 Sampling and monitoring 
    12.7.6 Compliance and enforcement 
    12.8 Chemical Spill Prevention and Response—The Hazardous Materials Incident Response Team 
    12.9 Sampling and Monitoring to reduce risk—the Collection System Monitoring Program 
    12.9.1 Data management and computerization 
    12.10 Conclusions: need for strong local programs to reduce risk 
    12.11 References 

    13 Lessons learned: a response and recovery framework for post-disaster scenarios 
    13.1 Introduction 
    13.1.1 Background 
    13.1.2 Rationale 
    13.1.3 Objectives 
    13.1.4 Methodology 
    13.1.5 General Principles
    13.2 Response and Recovery Framework 
    13.2.1 General Guidelines 
    13.2.2 Immediate Aftermath (0-7 Days) 
    13.2.3 Short Term (Next 60 days) 
    13.2.4 Medium term (Next 3-12 Months) 
    13.3 Conclusion
    13.4 References 

    14 Managing urban water risks: Managing drought and climate change risks in Australia 
    14.1 Introduction 
    14.2 Managing Drought Risks 
    14.3 Adapting to Climate Change Impacts 
    14.3.1 Climate Change Forecasts 
    14.3.2 Modeling of Impacts 
    14.3.3 Water Reforms and Environmental Flows 
    14.3.4 Climate Change Impacts 
    14.3.5 Adapting with Water Savings and Water Reuse 
    14.4 Adaptation Case Study 
    14.4.1 The Sydney Water System 
    14.4.2 The Sydney Metropolitan Water Plan 2006 
    14.4.3 Managing Drought Risks 
    14.4.4 Enhanced Stochastic Analyses 
    14.4.5 Economic Analyses 
    14.4.6 Another Example 
    14.5 Additional Drought Security Issues 
    14.5.1 Drought Severity 
    14.5.2 Hindcasting 
    14.5.3 Starting Storage 
    14.5.4 Demand Variability 
    14.5.5 Demand Hardening 
    14.5.6 Building Diverse Water Portfolios 
    14.6 Conclusions 
    14.7 References 



    Jimenez Cisneros\, Blanca; Rose\, Joan B.