· 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.
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.
