Opportunistic and Microbial Pathogens in Municipal Water Distribution Systems

Abstract

Municipal water quality in the distribution system and household water tanks were investigated relative to water chlorination, microbial regrowth and the presence of opportunistic and potential pathogens. The aim of this investigation is to evaluate water quality in the distribution system. The results revealed the storage reservoir at pumping station and distribution lines to residential houses complied with the Omani Drinking Water Standards. Three types of water tanks were examined: glass-reinforced-plastic (GRP), polyethylene (PE) and galvanized iron (GI). Based on the data, all water tanks supported microbial regrowth with high values of microbial total count. Microbial regrowth varied with type of water tanks. Coliforms were isolated from all tanks but were abundantly found in GRP. They were also isolated at end points. Kleblsiella spp were the dominant among the isolates. Enterobacter aerogenes was the dominant isolate in home filters with GRP and PE tanks. The houses with GI tanks, home filters were not used. Several forms of potential pathogens were found in the biofilms of the holding tanks and end points where Aeromonas was the most frequent isolate. In conclusion, holding tanks and end points appear to be a potential for microbial regrowth and it a threat to public health.