Application of semi-continuous culture on membrane filters for the study of activated sludge bacteria

Bacterial population of activated sludge flocs from the petrochemical wastewater purification plant was studied by semi-continuous culture on membrane filters. Almost all (90%) of bacterial cells in the flocs were metabolically active. Only a small fraction of bacteria in the flocs was able to use phenol or ethylene glycol as the sole source of carbon. At higher concentrations of these compounds growth of the bacteria was strongly retarded.