Urban Water Security: Managing Risks
UNESCO-IHP

Table of Contents

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 
4.4.3.1 Arsenic 
4.4.3.2 Mercury 
4.4.3.3 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 
4.5.2.1 Volatile Organic Compounds (VOCs) 
4.5.2.2 Solvents 
4.5.2.3 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 
4.6.1.1 China 
4.6.1.2 Japan 
4.6.1.3 United States of America 
4.6.2 Arsenic (As) 
4.6.2.1 Canada 
4.6.2.2 China 
4.6.2.3 United States of America 
4.6.3 Mercury 
4.6.3.1 Canada Arctic 
4.6.3.2 China 
4.6.3.3 Japan 
4.6.3.4 United States of America 
4.6.4 Volatile Organic Compounds (VOCs) 
4.6.4.1 Netherlands 
4.6.4.2 United States of America 
4.6.5 Trihalomethanes (THMs) 
4.6.5.1 Alaska 
4.6.5.2 Canada 
4.6.5.3 United Kingdom 
4.6.5.4 United States of America 
4.6.6 New Chemicals 
4.7 Chemical Risks in Urban Cities in Developing Countries 
4.7.1 Fluoride 
4.7.1.1 Brazil 
4.7.1.2 Ethiopia 
4.7.1.3 India 
4.7.1.4 Kenya 
4.7.1.5 Mexico 
4.7.1.6 Saudi Arabia 
4.7.1.7 South Africa 
4.7.1.8 Turkey 
4.7.1.9 United Republic of Tanzania 
4.7.2 Arsenic (As) 
4.7.2.1 Argentina 
4.7.2.2 Bangladesh – West Bengal, India 
4.7.2.3 Chile 
4.7.2.4 Mexico 
4.7.2.5 Taiwan 
4.7.2.6 Thailand 
4.7.2.7 Vietnam 
4.7.3 Mercury (Hg) 
4.7.3.1 Brazil 
4.7.3.2 Philippines 
4.7.3.3 South Africa 
4.7.4 Trihalomethanes (THMs) 
4.7.4.1 Greece 
4.7.4.2 Malaysia 
4.7.4.3 Mexico 
4.7.4.4 Turkey 
4.7.5 Pesticides 
4.7.5.1 Brazil 
4.7.5.2 Egypt 
4.7.5.3 South Africa 
4.8 Chemical Risk Management in Urban Water Cycle
4.8.1 Chemical Risks Identification in Urban Water Cycle 
4.8.1.1 Drinking water 
4.8.1.2 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 
7.2.1.1 Municipal wastewater 
7.2.1.2 Industrial wastewater 
7.2.1.3 Stormwater 
7.2.2 Non point pollutant sources 
7.2.2.1 Urban infrastructure 
7.2.2.2 Urban activities
7.2.2.3 Disposal practices 
7.2.2.4 Other sources 
7.3 Pollutants involved 
7.3.1 Conventional parameters 
7.3.2 Biological pollutants 
7.3.3 Emerging pollutants 
7.3.3.1 Content in water 
7.3.3.2 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 
7.4.4.1 Groundwater 
7.4.4.2 Surface water 
7.4.5 Pollutant management 
7.4.5.1 Biological pollutants 
7.4.5.2 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 
7.6.1.1 Soil disposal and aquifer storage 
7.6.1.2 Soil disposal and agriculture 
7.6.2 Disposal in water bodies 
7.6.2.1 Eutrophication 
7.6.2.2 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