MICROFLORA OF ACTIVATED SLUDGE

Abstract

Fifty-four bacterial strains were isolated from the Tongariro National Park activated sludge. Of these, only 4 strains were capable of forming floc in proteose peptone-yeast extract (PPYE) but 6 strains of Pseudomonas sp. produced floc in synthetic sewage. The activated sludge was easily reconstructed by mixing the isolated bacteria at random. The chemical oxygen demand (COD) removal activities of these reconstructed sludges were twice as much as that of the original activated sludge. The reconstructed activated sludges from the pure cultures had almost the same activity as the original activated sludge.
Sugar components, from NH₃-extracted fraction of the activated sludge polymer, were mainly glucose, and minor quantities of pentose and glucuronic acid; but those from EDTA-extracted fraction were mainly glucuronic acid and small amount of glucose and pentose.