AWWA QTC97173

Historically, the study of the microbiology of drinking water has focused primarily on the occurrence of bacteria. The conditions which encourage the proliferation of fungi in distribution systems (if indeed they do proliferate) have not been investigated. This paper reports the results of work funded by the American Water Works Association Research Foundation to obtain a better understanding of the significance of fungi found in distribution systems. A questionnaire was sent to 490 major water utilities to establish a history of known occurrences of fungi. The seasonal occurrence of fungi was assessed by determining the quantity and identity of isolates from samples collected from two utilities over a 12-month period. The growth of fungi in water systems and the production of secondary metabolites were also investigated. The production of an odor-causing compound, TCA, by fungi was also studied. Finally, the fungi removal efficiency of various treatment techniques was explored.