scope:

The spores of sulfite-reducing anaerobes (clostridia) are widespread in the environment. They are present in human and animal faecal matter, in waste watter and in soil. Unlike Escherichia coli and other coliform organisms, the spores survive in water for long periods as they are more resistant than vegetative forms to the action of chemical and physical factors. They may thus give an indication of remote or intermittent pollution. They may even be resistance to chlorination at levels which are normally used for the treatment of water, and they are thus useful for control purposes. The method can be used to all types of water, except when a large amount of particulate material is liable to be retained by the membrane.