VD.194-Membrane filtration to test for faecal contamination of water samples - ( WEDC ).

Thermotolerant faecal coliforms are indicator bacteria, which can form colonies at 44 degrees centigrade and can provide evidence of faecal contamination of water.

Membrane filtration is a means of testing the quality of water.

This film presents an overview of the process. Water is filtered though a membrane having pore sizes smaller than the size of a bacterium.

As water is filtered, bacteria are collected on the surface of the membrane.

The bacteria can then be incubated to produce visible colonies suitable for analysis.