A SURVEY OF FILAMENTOUS FOAMING IN ACTIVATED-SLUDGE PLANTS IN HONG-KONG

Of five major secondary sewage treatment works surveyed during 1993 in Hong Kong, two had frequent foaming in the activated sludge plants wh ich resulted in unmanageable operational problems. In this study, bran ched filamentous Nocardia amarae was identified as the main causative bacteria in foaming sludges. In vitro studies showed that fatty acids that are commonly found in municipal sewage could be utilized by N. am arae as the sole carbon source, and presence of these fatty acids in s ewage could stimulate growth.