Practical Basis for Disinfection of Drinking Water

Appunti cronologici dello sviluppo socio-culturale e economico di Trieste

A Reference Manual for Health Professionals and Water Technicians

Why this book

Waterborne diseases remain nowadays, in the beginning of the 3rd Millennium, one of the major health concerns in the developed and developing World.

Control of the microbial quality of drinking water should be a priority in all countries, given the immediate and potentially devastating consequences of waterborne infectious diseases (WHO, 2004). Diarrhoeal diseases, which are largely derived from poor water and sanitation account for 2,4 million deaths each year, and contribute over 73 million Disability Adjusted Life Years. On a global scale, this places diarrhoeal disease as the sixth highest cause of mortality and the third in the list of morbidity.

At present estimates, one-sixth of humanity (more than 1 billion people) lack access to any form of improved water supply within 1 kilometre of their home. In addition, social and environmental changes continue to result in new and re-emerging waterborne pathogens.

 The 1976 UN habitat Conference in Vancouver suggested that the international community should aim to provide water services to all rural and urban dwellers by 1990. Nowadays, 15 years later, the problem of water sanitation still represents a big concern for all communities of developing countries. Much has been done, but more to be done!

This Guidelines for provision of safe water have been customized to the existing infrastructures in developing countries and based on the author past experiences in sub-Saharan belt, especially in Somalia and Chad during cholera outbreak in refugee camps and civil wars under the supervision of the EU and WHO, from the eighties up to date.

Specifically, low cost appropriate technology for implementation by non-skilled manpower is detailed in this document. Various water disinfection techniques such as ozonization, UV lamps, inverse osmosis, etc, are beyond the scope of this review, and are just mentioned in the glossary. This emphasis on appropriate and affordable technology attempts to help deprived communities of developing countries accept responsibility for the management of their own water supply, using local know-how and available material with minimal dependency on either imported material or professional manpower.

 

Foreword – Why this book

Contents

List of Tables

Acknowledgements

Commonly used Abbreviations and Symbols

Commonly used Weights & Measures

Types of Water Sources
Deep ground-waters
Shallow ground-waters
Surface waters.
Up-land lakes & reservoirs
Surface waters. Rivers, canals & low-land reservoirs

Water & Disinfection
Surface water abstraction and treatment
Water disinfection
Tanker trucks and water storage containers
Water storage at household level
General advice

Part 1.  Application of Chlorine to Household Sources
Combined Chlorination-Coagulation-Flocculation & Filtration systems

  • About the system
  • Type
  • Area of use
  • Trade name (PUR®)
  • Treatment process
  • PUR®-purifier of water provide effective reduction against
  • Packing
  • Storage
  • Proprieties
  • Advantages of the product
  • Disadvantages of the product
  • Technical data sheet

Chlorinated isocyanuric compounds (CICs)

  • Type
  • Trade names (Aquatabs®, Babysteril®, Bionil® , Haz-tab®, Biosept®, Presept® )
  • If water is not clear (treatment of turbid water)
  • Water storage tanks and tankers: Cleaning and Disinfection
  • Economy note
  • Warning
  • Advantages of the product
  • Disadvantages of the product
  • Technical data sheet

Calcium hypochlorite

  • High-Test Hypochlorite (HTH) or calcium hypochlorite
  • Type
  • How to prepare “Stock solution - 1”
  • How to prepare “Stock solution - 2”
  • How to prepare “Stock solution - 3”
  • How to prepare “Stock solution in Emergency situation”
  • If water is not clear (Turbid water treatment)
  • To disinfect the water
  • Levels of free residual chlorine necessary for safe water
  • Household vessels for water collection and storage - Hazard analysis & Disinfection
  • Storage tanks and tankers – Cleaning & Disinfection
  • Caution
  • Testing for bacteria
  • Safety for operators handling chlorine

Sodium hypochlorite

  • Stabilization of sodium hypochlorite solutions
  • Hard water and sodium hypochlorite dilution
  • If water is not clear (treatment of turbid water)
  • Sodium hypochlorite generators
  • How to determine the volume of sodium hypochlorite needed for water disinfection
  • Caution
  • Advantages of the product
  • Disadvantages of the product
  • Technical data sheet
  • Control of Mosquito vectors
  • Fact sheet: Domestic water-storage containers & Chemical control of Mosquito vectors

Part 2. Application of Chlorine to Controlled Water Sources

Disinfection of controlled water sources

  • Free chlorine residual
  • Pathogen’s resistance to chemical water disinfection
  • Calculation of water volume in different containers
  • Key points of water treatment

Proper well construction and maintenance

  • The ground-water
  • Types of wells
  • Proper construction of new wells
  • Well maintenance
  • Planning a water system
  • Well disinfection must be performed under following circumstances
  • Fact sheet: Safety: Respiratory, Chemical, Electrical

Protection of traditional ponds
The maintenance operations of ponds are as follow
Unused wells
Well chlorination and water aeration
Calculating the amount of water in the well
Calculating the chlorine dosage: Emergency, Public, Individual systems
Applying chlorine
Testing for chlorine residual
Fact sheet: Chlorination Yes & No
Preparation of chlorine stock solution
Shock chlorination of wells and springs

  • Definition
  • When shock chlorination is recommended
  • Before shock chlorination, follow carefully these simple suggestions
  • Practical recommendations for shock chlorination
  • Safety precautions

Continuous chlorination of dug wells

  • The repeated addition of chlorine
  • Raising the free residual concentration of chlorine

Chlorination of boreholes
Testing for bacteria
Fact sheet: Protect your well
Modified Horrocks’ method of chlorination

Part 3. Program Logistics

Cultural aspects and failures
Economic aspects
Drinking water awareness and education programme

  • Awareness campaign
  • Training of water technicians

Fact sheet: Training – 10 basic information

Part 4. Water-borne Outbreaks

Introduction
General incident response

  • Data collection
  • Emergency procedures

Key data and general description of the emergency

  • Basic information
  • Demographic data
  • Geographical information
  • Tracing the causes of the incident

Emergency standard operating procedures

  • Personnel and supplies
  • Water supply
  • Sewage and disposal
  • Solid waste disposal
  • Human settlements
  • Food hygiene, Nutrition, and Water provision
  • Corpses
  • Vector control
  • Health care structures

Part 5. Antimicrobial agents & Water-borne diseases

Bacterial water-borne diseases

  • Campylobacteriosis
  • Escherichia coli
  • Salmonellosis
  • Leptospirosis

Protozoan water-borne diseases

  • Cryptosporidiosis
  • Cyclosporiasis
  • Giardiasis
  • Toxoplasmosis

Part 6. Essential Laboratory

Introduction
Understanding a water test report
Drinking water standards
Microbiological contaminants
Check water system
Bacteriological tests
Sample collection, Frequency of sampling & Volume of sample

  • Sampling from a stream
  • Sampling from a well
  • Sampling from a tap
  • Frequency of sampling
  • Bacteria sampling
  • Volume of sample

Preparation for the bacteriological test

  • Making up MacConkey broth
  • Sterilization
  • General cleanliness

Bacteriological test procedures
Water quality colorimetric test
Membrane filtration
Interpretation of results
Equipment: Water testing kit
Inorganic chemical contaminants
Sample collection for suspected chemical pollution
Other water quality parameters
Summary description for testing suspected water chemical contamination
Laboratory tests for suspected contamination
Treatment options

Part 7. Water Quality for Health Care Institutions

Introductive note
Pathogens in drinking water
Baths and pools
Pharmaceutical water
Fact sheet: Filtration
Design and operation of distribution networks
Persistence of pathogens in water lines and containers of health-care settings

  • Choice of water source
  • Water as reservoir of hospital pathogens
  • Water storage and distribution
  • Biofilm formation
  • Disinfection of water storage tanks
  • Disinfection of the distribution network
  • Disinfection of water mains after construction and repair
  • Principles of microbial monitoring in water lines and containers

Part 8. Water Quality for Livestock Drinking

Introductive note
Pathogens
Transmission, Signs & Symptoms, Treatment
Prevention
Common water contaminants
Mineralized (salty) water
Nitrate
Achieving quality water
Water contaminants & testing

Part 9.Appendix

Technical data sheet: Sodium hypochlorite
Technical data sheet: Calcium hypochlorite
Technical data sheet: Sodium dichloroisocyanurate
Technical data sheet: Ferric sulphate & Calcium hypochlorite
Larvicides

  • General information on Vector control
    Background
    Mosquitoes
    Prevention
    Larvicides
    Target area
    Selection of insecticides
    Application procedures
    Treatment cycle
    Resistance
    Precautions
  • Some basic information about Microbial and Chemical larvicides, and some adulticides
    Bacillus thuringiensis israelensis
    Bacillus Sphaericus
    Methoprene
    Temephos
    Monomolecular films
    Oils
    Malathion
    Synthetic pyrethroids
    Naled

Conversion tables

Part 10. Glossary

Part 11. References and further reading

Part 12. General index