ENUMERATION OF FAECAL INDICATOR BACTERIA IN LARGE WATER VOLUMES USING ON SITE MEMBRANE FILTRATION TO ASSESS WATER TREATMENT EFFICIENCY

Bacteria isolation method. With sample volumes as tested in routine microbiological monitoring for the presence and absence of faecal indicator bacteria in treated water, the actual concentration in the final stages of water treatment cannot be assessed. Consequently, no accurate information can be obtained about the removal efficiency of a water treatment for microorganisms. Therefore, a method for on site isolation of faecal indicator bacteria from large volumes (100 l or more) of treated water using membranes filtration (MF-sampling) was developped and tested. The procedures for culturing the isolated microorganisms were similar to those applied in the routine methods for small volumes using membrane filtration (mf-method).