Field water disinfection

field water disinfection

Of the 4.400 million square kilometres (1.700 million square miles) of water on earth, less than 0,5 is potable, and about 70 of all available freshwater is used for agriculture. Yet because of inefficient irrigation systems, particularly in developing countries, 60%of this water is lost to evaporation or is returned to rivers and ground-water aquifers. Water withdrawals for irrigation have increased by over 60%since 1960. About 40%of the world’s population currently lives in areas with moderate to high water stress, and by 2025 it is estimated that about ⅔ of the world population (about 5,5 billion people) will live in areas facing such water stress.

 

In tropical areas and developing countries, water has a complex relationship with spread of disease. Worldwide, 1.5 billion rural people and 200 million urban people in the world suffer from the lack of safe drinking water and adequate sanitation. Some estimates suggest that 80%of the world’s diseases are linked to inadequate water supply and sanitation. Between 10 and 25 million people die each year (28.000 to 68.000 persons each day) from diseases caused by contaminated water.

In India, an estimated 66 million people rely on groundwater with fluoride concentrations exceeding recommended norms. In the Ganges Plain of northern India and Bangladesh severe natural pollution by arsenic affects 25%of water wells.

 

Moreover some contaminating organisms can escape the disinfection process entering the water supply distribution system through breaks and joints or cracks in the pipeline. In all physical methods of water disinfection there is the possibility that water be re-contaminated at household level during handling or storage.

 

Many of the diseases related to man-made lakes and irrigation are debilitating and chronic, and the effect of these infections (e.g. schistosomiasis, onchocerciasis) on productivity is substantial. A specific percentage of such water projects costs should be devoted to health planning and preventive measures. Epidemiologists, with detailed knowledge of the local disease ecology must be employed, and a process of bargaining must go on between the epidemiologists, engineers, and economists.

Too often the projects are designed by teams of agronomists, engineers, and economists with little or no epidemiological input.

 

Centralized water treatment and distribution systems are expensive and take years to complete. To provide the under-served with potable water in the short term requires innovative practical solutions such as point-of-use disinfection and safe water storage vessels. The following guidelines, for the provision of safe water, are intended to professionals and non–skilled manpower for implementation of their own water supply with minimal dependency on imported materials.

 

The Author

 

Contents

  • List of Tables
  • Acknowledgements
  • Commonly used Abbreviations & Symbols
  • Commonly used Weights & Measures
  • Water a matter of LIFE and DEATH
  • Introductive note
  • General Microbiological considerations & Planning for health
  • Part 1 Field water treatment methods: Chlorine
  • Characteristics and notes
  • Organisms’ resistance to chlorine
  • Virucidal effectiveness
  • Quantity of chlorine needed for disinfection of different items
  • Advantages of chlorine disinfection techniques
  • Disadvantages of chlorine disinfection techniques
  • Part 2 Field water treatment methods: Iodine
  • Characteristics and notes
  • Iodine crystals: two disinfection techniques
  • Iodine tablets
  • Iodinated exchange resin
  • Advantages of iodine disinfection techniques
  • Disadvantages of iodine disinfection techniques
  • Summary description of essential practical characteristics of Iodine and Chlorine in water disinfection policies
  • Part 3 Field water treatment methods: Combined treatment systems 23
  • PUR water treatment system - Feature of product
  • Type
  • Area of use
  • Treatment process
  • The new PUR water treatment system may provide effective reduction against …
  • Packing
  • Storage
  • Proprieties
  • Advantages of combined treatment systems
  • Disadvantages of combined treatment systems
  • Part 4 Field water treatment methods: Chlorinated isocyanuric compounds
  • Features of the product
  • Symbols & Synonyms
  • Dosage & Contact time
  • Economy note
  • Area of use
  • Advantages of chlorinated isocyanuric compounds
  • Disadvantages of chlorinated isocyanuric compounds
  • Trade names
  • Warning
  • Part 5 Field water treatment methods: Lemon juice
  • Part 6 Field water treatment methods: Silver (Ag)
  • Part 7 Field water treatment methods: Potassium permanganate (KMnO4)
  • Part 8 Field water treatment methods: Filtration
  • Characteristics and notes
  • Three broad classes of contaminants found in water
  • Filter classification
  • When purchasing a filter, ask the following questions
  • General and Economic considerations
  • Ceramic filter
  • Effectiveness & costs
  • Ceramic filter maintenance
  • Advantages of ceramic filtration
  • Disadvantages of ceramic filtration
  • Activated carbon filtration
  • When purchasing an Activated Carbon filter, ask the following questions
  • River bank filtration
  • Slow sand filtration
  • Part 9 Field water treatment methods: Boiling
  • Characteristics and notes
  • Heat resistance varies with different micro-organisms
  • Exposition time
  • Advantages of boiling
  • Disadvantages of boiling
  • Part 10 Field water treatment methods: Ultraviolet radiations
  • Solar water disinfection (SODIS)
  • The procedure
  • Advantages of solar water disinfection
  • Disadvantages of solar water disinfection
  • Fact Sheet: SODIS -a specific problem
  • Ultraviolet lamps
  • Low & Medium pressure ultraviolet lamps
  • Household ultraviolet lamps disinfection system
  • Ultraviolet lamps and Bacterial reactivation
  • Ultraviolet lamps and Energy requirements
  • Ultraviolet lamps and Operating costs
  • Advantages of Ultraviolet disinfection systems
  • Disadvantages of Ultraviolet disinfection systems
  • Part 11 Other water purification techniques
  • Distillation
  • Design & Weight of distillers
  • Features of distillers
  • Cleaning & Maintenance of distillers
  • Costs of distillers
  • Advantages of distillers
  • Disadvantages of distillers
  • Membrane filtration
  • Reverse osmosis (RO)
  • Advantages of reverse osmosis
  • Disadvantages of reverse osmosis
  • Ion exchange (Water softeners)
  • Part 12 Recommended Technique
  • When purchasing a treatment system, ask the following questions
  • Part 13 Prevention & Treatment methods
  • Part 14 Shipping & Storage
  • Calcium hypochlorite
  • Sodium dichloroisocyanurate
  • Sodium hypochlorite
  • Tetraglycine hydroperiodide
  • Ferric sulphate & Calcium hypochlorite (Pur®)
  • Part 15 Comparative acute Oral Toxicity data
  • Part 16 Conclusions
  • Part 17 Appendices
  • Waterborne Diseases - Elective disinfection for main Human Parasitic Protozoans & Helmiths
  • Household gravity sand filter
  • Mapping the catchment area
  • Pathogens associated with water-borne infections
  • Disasters and water supply
  • Bioterrorism – Intentional contamination of water
  • Life cycles:
  • Amoebiasis
  • Cryptosporidiosis
  • Dracunculiasis
  • Giardiasis
  • Isosporiasis
  • Microsporidiosis
  • Schistosomiasis
  • Conversion tables
  • Part 18 Glossary of Water, Sanitation, Hygiene & Health
  • Part 19 Water quiz – Test your knowledge
  • Part 20 References & Water related websites
  • Part 21 General index