OCCURRENCE OF BACTERIA IN DESIGN FEATURES OF A DISTRIBUTION SYSTEM
Report No FR0487
These studies will provide information regarding the potential of design features of a distribution system to cause a deterioration in the microbial quality of water.
To carry out a scoping study to assess if selected design features of distribution systems could act as a niche for coliform and heterotrophic bacteria.
Many water utilities experience bacteriological failures where the source of contamination can not be identified. Distribution systems contain a variety of features which may exert an influence on the microbial quality of water by providing niches for colonisation by micro-organisms or form 'dead' volumes of water in which chlorine residuals diminish to a concentration which permits microbial growth.
V RESUME OF CONTENTS
This final report is one of several dealing with specific topics studied as part of the FWR contract Water Quality in Distribution (Project Ref F-1702). It describes the outcome of a scoping study to investigate how certain design features of a distribution system could influence microbiological quality. Several design features were selected for investigation including service reservoirs, hydrants and closed valves as well as dead ends. Sampling protocols were developed and used to obtain samples of water and 'biofilm' from a number of distribution systems. The extent to which each of these features would influence microbial quality was assessed in terms of numbers of heterotrophic and coliform bacteria.
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