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close this bookGuidelines for Drinking Water Quality - Training Pack (WHO)
View the document(introduction...)
View the documentPreface
View the documentWater and Public Health
View the documentThe WHO Guidelines for Drinking-Water Quality
View the documentMicrobiological Aspects
View the documentDisinfectants and Disinfection By-Products
View the documentInorganic Constituents and Aesthetic Parameters
View the documentOrganic Chemicals
View the documentPesticides in Drinking-Water
View the documentMonitoring and Assessment of Microbiological Quality
View the documentMonitoring and Assessment of Chemical Quality
View the documentGuidelines for Drinking-Water Quality Volume 3
View the documentSource Protection
View the documentWater Treatment
View the documentDisinfection
View the documentWater Treatment Chemicals and Construction Materials
View the documentInstitutional Frameworks
View the documentLegislative Frameworks
View the documentEstablishing National Drinking-Water Standards
View the documentHuman Resources
View the documentCost Recovery
View the documentMicrobiology (Practical Exercise)
View the documentDisinfection (Practical Exercise)
View the documentSanitary Inspection (Practical Exercise)
View the documentPlanning (Practical Exercise)

Microbiology (Practical Exercise)

Session Objectives

· To discuss the relative advantages and disadvantages of the membrane filtration and multiple tube methods of analysis.

· To provide participants with a practical experience of the membrane filtration technique.

· To provide participants with a practical example of the use of different volumes of filtration for different qualities of water.

· To review results and discuss precision of analysis.


NB: It is assumed that whoever takes this practical has a good working knowledge of microbiological techniques.

1. Collect two samples for testing (at least 1 litre of each) - one clean water and one contaminated water (from a river, stream, pond etc.).

2. Demonstrate the membrane filtration technique and describe dilution methods (e.g. to make a 1 per cent solution add 1ml of sample to 99ml of distilled water).

3. Highlight the advantages and disadvantages of both the membrane filtration and the multiple tube methods of analysis.

4. Ask the participants to prepare and filter the following samples: 100ml; 50ml; 10ml; and 1ml.

5. Ask the participants to read the results the following day and record and compare the results.

6. A demonstration of other techniques - e.g. colilert - may also be given if resources permit.