Characterization of Residual Organics from Biological Treatment

Abstract

<p> Gel filtration chromatography on Sephadex gels G15 and G50, was used to characterize the residual organic materials found in effluents from biological treatment. Molecular weight distributions were determined as the equivalent molecular weight distribution of a homologous series of sugars and alcohols. The homologous series was also used to determine equivalent molecular radii, based on Corey-Pauling-Koltun space filling models of the homolgous series.</p> <p> To determine the distributions of residual organics from mixed cultures grown on simple, pure substrates, laboratory batch studies were performed. For this purpose, media containing glucose or glutamic acid substrates and a bicarbonate-phosphate buffer system were innoculated with activated sludge. Both high and low substrate and microorganism concentrations were used at constant temperature and pH. As a comparison for the mixed cultures, a representative strain of Flavobacterium sp. isolated from activated sludge was grown in pure culture on glucose.</p> <p> Both the laboratory mixed culture effluents and treatment plant effluents contained material of equivalent molecular weight less than 1500. However, little similarity appeared to exist between the low molecular weight (<1500) distributions of treatment plant effluents and those from the mixed cultures. A significant fraction of the treatment plant and batch effluents had equivalent molecular weights of greater than 10,000. The pure culture studies showed that a single strain of bacteria can produce material of equivalent molecular weight both greater and less than 1500.</p>