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Boiling

Author/Compiled by
Lerica G. Shrestha (Environment and Public Health Organization, ENPHO)
Raju Shrestha (Environment and Public Health Organization, ENPHO)
Dorothee Spuhler (seecon international gmbh)
Executive Summary

Boiling drinking water with fuel is the oldest and most commonly practiced household water treatment method. According to WHO, water needs to be heated until the appearance of the first big bubbles to ensure that it is pathogen free. Many organizations recommend boiling both for water treatment in developing countries and to provide safe drinking water in emergency situations throughout the world - though it is quite laborious and uses a lot of energy. Boiling only kills pathogens and does not remove turbidity or chemical pollution (e.g. arsenic) from drinking water. So prior to boiling, water can be purified by settling or filtration method.

Advantages
Effectively kills most pathogens.
Easy, simple and widely accepted method of disinfection (particularly in tea-consuming cultures)
Biogas cooking stoves can be used for the cooking stove (e.g. biogas linked toilet)
Disadvantages
Can be costly due to fuel consumptions
Use of traditional fuel (firewood, kerosene/gas) contributes to deforestation and indoor air pollution
Potential user taste objections
Risk of injuries (especially when children are around)
Does not remove turbidity, chemicals, taste, smell, colour
Time consuming
Water needs to cool down before use unless for hot drinks
In Out

Freshwater

Drinking Water

Introduction

Boiling is oldest and most effective household drinking water treatment. It is promoted in both developing countries where water is routinely of uncertain microbial quality and in developed countries when conventional water treatment fails or water supplies are interrupted as a result of disasters or other emergencies. 21.2% of the population in South-east Asia report boiling their water before drinking it (ROSA & CLASEN, Unpublished data, 2008).

The WHO recommends bringing water to a rolling boil as an indication that a disinfection temperature has been achieved (WHO 2008). If practised correctly, boiling is one of the most effective water treatment methods to kill or deactivate all classes of waterborne pathogens, including bacterial spores and protozoan cysts that have shown resistance to chemical disinfection and viruses that are too small to be mechanically removed by microfiltration (BLOCK 2001). Heating water to even 55 °C has been shown to kill or inactivate most pathogenic bacteria, viruses, helminths and protozoa that are commonly water borne (FEACHEM et al. 1983). A clean container should be used for the boiling and after boiling, water should be stored in a clean and covered container, and handled carefully (no utensils should be brought in contact with the water, thus water needs to be poured in another clean recipient for consumption) to minimise the recontamination.
Despite its effectiveness and simplicity, boiling has the disadvantage to require affordable and sufficient fuel to have properly boiled water for a regular drinking purpose, and is quite labour intensive.

Boiling disinfecting drinking water. Source: ENPHO (2007)

Boiling disinfecting drinking water. Source: ENPHO (2007)


Effectiveness

If the boiling point is reached, boiling is effective in killing bacteria, viruses, protozoa, helminths and most pathogens from drinking water. Incomplete inactivation of pathogens in boiled water is attributed to users not heating the water to the boiling point and/or recontamination of boiled water in storage.Boiling does not remove turbidity, chemicals (e.g. arsenic), taste, smell or colour from water. Therefore, settling or even filtration (by cloth or slow sand or biosand filter) is often needed prior to boiling.

 

 

Bacteria

Viruses

Protozoa

Helminths

Laboratory

100%

100%

100%

100%

Field

97-99%

NA

NA

NA


 

Summary of treatment efficiency of boiling. Source: adapted from CAWST (2009)

Applicability

Chemical pollution such as arsenic is not removed by boiling. Also water with high amounts iron (with reddish colour), calcium or chlorine is not suitable for boiling. White scales may deposit in container bottom after boiling if calcium is high in waters. In such case, the container should be washed properly after every use. Boiled water tastes flat and people may not like that. Thus, boiled water can be chilled in freezer or cooled down to room temperature to have good taste.

Boiling is suitable where enough fuel sources (e.g. wood, kerosene, electricity, gas, charcoal etc.) are locally available all the time in affordable cost.
Especially in densely populated areas, boiling with fuel wood is not appropriate to the overexploitation of the wood resources and the subsequent environmental damage such as desertification and soil erosion.
Boiled water may cause burn injuries if not handled properly. Long term exposure in fire or stove smoke of the person boiling the water may cause associated respiratory diseases. For this indoor cooking space should be made well ventilated.

Library references

Amoeba and Water

This children’s book provides information on safe drinking water, ways of water contamination, simple HWTS options presented in attractive illustrations and simple languages so that school children can easily understand them.

ENPHO (2007): Kathmandu and New York: Environment and Public Health Organization (ENPHO) and United Nations Children's Fund (UNICEF) URL [Accessed: 09.04.2010]

Guidelines for Drinking-water Quality, Third Edition

This volume of the Guidelines for Drinking-water Quality explains requirements to ensure drinking-water safety, including minimum procedures and specific guideline values, and how those requirements are intended to be used. The volume also describes the approaches used in deriving the guidelines, including guideline values. It includes fact sheets on significant microbial and chemical hazards.

WHO (2008): Third Edition incorporating the First and Second Addenda. Geneva: World Health Organization (WHO) URL [Accessed: 23.04.2012]

Microbiological Effectiveness and Cost of Disinfecting Water by Boiling in Semi-urban India

This paper tries to assess improvement of microbiological quality in drinking water by boiling and cost analysis of boiling in Virar, Vasai and Nalasopara, three sprawling semi-urban communities in India.

CLASEN, T. ; MCLAUGHLIN, C. ; NAYAAR, N. ; BOISSON, S. ; GUPTA, R. ; DESAI, D. ; SHAH, N. ; (2008): Deerfield: The American Society of Tropical Medicine and Hygiene (ASRMH) URL [Accessed: 20.07.2010]
Further Readings

Boiling. Fact Sheet - Simplified

A 3-page factsheet on water boiling, focussing on treatment efficiency, operating criteria and other information on boiling.

CAWST (2009): Calgary: Centre for Affordable Water and Sanitation Technology (CAWST) URL [Accessed: 01.04.2010]

Boiling. CDC-USAID Household Water Treatment Options in Developing Countries Factsheets

A single page factsheet with descriptions from the field and the lab. Describes effectiveness, advantages and limitations of boiling.

CDC ; USAID (2009): (= CDC-USAID Household Water Treatment Options in Developing Countries Factsheets ). New York: Center for Disease Control and Prevention (CDC) and United States Agency for International Development (USAID) URL [Accessed: 14.07.2010]

Smart Water Solutions

This booklet on water gives examples of innovations such as the use of sunlight to purify water, effective low-cost water filters, low-cost drip irrigation and locally produced hand pumps that are five times cheaper than imported pumps.

NWP (2006): Examples of innovative, low-cost technologies for wells, pumps, storage, irrigation and water treatment. (= Smart water solutions ). Amsterdam: Netherlands Water Partnership (NWP) URL [Accessed: 06.09.2011]

Smart Disinfection Solutions

This booklet, part of the Smart Water Solutions series provides a wide range of methods and products for home water treatment in rural areas.

NWP (2010): Examples of small-scale disinfection products for safe drinking water. (= Smart water solutions ). Amsterdam: KIT Publishers URL [Accessed: 07.07.2010]

Household water treatment 1. Well Factsheet

This Technical Brief is the first of two examining the treatment of water in the home. The subject is introduced, and treatment by straining, storage, settlement, solar disinfection, chemical disinfection, and boiling are covered.

SKINNER, B. ; SHAW, R. ; (1999): London & Loughborough: Water And Environmental Health at London and Loughborough (Well) URL [Accessed: 05.05.2010]

Source Book of Alternative Technologies for Freshwater Augmentation in Latin America and the Caribbean

The Latin American and Caribbean countries have seen growing pressure on water resources, with increasing demand and costs, for agricultural, domestic and industrial consumption. This has brought about the need to maximize and augment the use of existing or unexploited sources of freshwater. There are many modern and traditional alternative technologies for improving the utility and augmenting the supply of water being employed in various countries, but with limited application elsewhere due to the lack of information transfer among water resources managers and planners. This book was prepared to provide water resource managers and planners, especially in developing countries and in countries with economies in transition, with information on the range of technologies that have been developed and used in the various countries throughout the world.

UNEP (1998): Nairobi: United Nations Environment Programme (UNEP) URL [Accessed: 17.10.2011]

Conservation et Traitement de l Eau a Domicile

This practical guide provides a review of different processing techniques and adequate water conservation at home and is structured around 10 key questions that should be posed before choosing a suitable solution.

DESILLE, D. ; (2013): Paris: Programme Solidarite Eau (PSeau) URL [Accessed: 06.06.2013]
Case Studies

Microbiological Effectiveness and Cost of Disinfecting Water by Boiling in Semi-urban India

This paper tries to assess improvement of microbiological quality in drinking water by boiling and cost analysis of boiling in Virar, Vasai and Nalasopara, three sprawling semi-urban communities in India.

CLASEN, T. ; MCLAUGHLIN, C. ; NAYAAR, N. ; BOISSON, S. ; GUPTA, R. ; DESAI, D. ; SHAH, N. ; (2008): Deerfield: The American Society of Tropical Medicine and Hygiene (ASRMH) URL [Accessed: 20.07.2010]

Scaling Up Household Water Treatment Among Low-Income Populations

This report examines the evidence to date regarding the scalability of HWTS. It seeks to consolidate existing knowledge and experience and distil the lessons learnt. Its primary aims are to 1) review the development and evolution of leading household water treatment technologies in their efforts to achieve scale, 2) identify the main constraints that they have encountered and 3) recommend ways forward.

CLASEN, T.D. ; (2009): (PhD Thesis). Geneva: World Health Organization (WHO) URL [Accessed: 09.04.2010]
Training Material

Household Water Treatment Options, Technical Reference and Training Guide

This training manual on household water treatment options provides information on safe water, water pollution sources, water quality situation of Nepal and various household treatment options including introduction, its advantages and limitation with points to remember while boiling on pages 14 and 15 (Nepali).

DWSS (2008): Kathmandu, Nepal: Department of Water Supply and Sewerage (DWSS)

Household Water Treatment Manual

This manual on household water treatment system includes various useful topics on safe water and multi barrier approach (source protection, sedimentation, filtration, disinfection and safe storage).

CAWST (2008): Calgary: Centre for Affordable Water and Sanitation Technology (CAWST)
Awareness Raising Material

Flip Chart on HWTS

Flipchart presentation on description of different household water treatment options including introduction, installation and organisation and maintenance procedures of each technology (in Nepali).

DWSS (2007): Nepal: Department of Water Supply and Sewerage (DWSS)

Household Water Treatment Options. Notebook Cover

A short publication with illustrations on different household water treatment options, which is designed to provide information on household water treatment to school children.

DWSS (2007): Kathmandu, Nepal: Department of Water Supply and Sewerage (DWSS)

Household Water Treatment Options. Factsheet

Factsheet on different household water treatment options and safe storage with its advantages and limitations, including description of boiling. (Nepali)

DWSS (2007): Kathmandu, Nepal: Department of Water Supply and Sewerage (DWSS)

Amoeba and Water

This children’s book provides information on safe drinking water, ways of water contamination, simple HWTS options presented in attractive illustrations and simple languages so that school children can easily understand them.

ENPHO (2007): Kathmandu and New York: Environment and Public Health Organization (ENPHO) and United Nations Children's Fund (UNICEF) URL [Accessed: 09.04.2010]

Alternative Versions to

No Structure Described.