Table 7.9Use of indicator organisms in monitoring

Microorganism(s)Type of monitoring
Validation of processOperationalVerification and surveillance
E. coli (or thermotolerant coliforms)Not applicableNot applicableFaecal indicator
Total coliformsNot applicableIndicator for cleanliness and integrity of distribution systemsNot applicable
Heterotrophic plate countsIndicator for effectiveness of disinfection of bacteriaIndicator for effectiveness of disinfection processes and cleanliness and integrity of distribution systemsNot applicable
Clostridium perfringens a Indicator for effectiveness of disinfection and physical removal processes for viruses and protozoaNot applicableNot applicableb
Coliphages Bacteroides fragilis phages Enteric virusesIndicator for effectiveness of disinfection and physical removal processes for virusesNot applicableNot applicableb
a

Use of Clostridium perfringens for validation will depend on the treatment process being assessed.

b

Could be used for verification where source waters are known to be contaminated with enteric viruses and protozoa or where such contamination is suspected as a result of impacts of human faecal waste.

From: 7, Microbial aspects

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