Studies of Sewage Purification: XIII. The Biology of Sphaerotilus natans Kutzing in Relation to Bulking of Activated Sludge

Abstract

S. natans has long been associated with the troublesome bulking of activated sludge in sewage disposal plants, and is usually the dominant organism at such times. Pure-culture studies have shown that excessive amts. of organic carbonaceous or proteinaceous matter tend to produce excessive growths of the fungus, but these conditions are usually not present when bulking occurs, and plant operation, rather than sewage composition. probably causes the bulking, Sphaerotilus being incidental to, rather than a cause of bulking. Probably the best killing agent for the plant is Cl. The nutritive requirements of S. natans are shown by tables, and its taxonomic position is discussed.