Membrane filtration to test for faecal contamination of water samples

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.