Dehydrogenases activity of activated sludge

Abstract

A study of dehydrogenases activity of activated sludge, return activated sludge, and waste activated sludge from three sewage treatment plants was made. Dehydrogenases activity and protein content of the mixed liquor varied along the aeration basin. Chromium chloride and zinc sulfate were found to be inhibitory to dehydrogenases activity. Return activated sludge and waste activated sludge, in spite of higher content of volatile suspended solids, contained lower dehydrogenases activity. Return activated sludge when kept without aeration and addition of sewage, showed higher dehydrogenases activity; and on aeration, but without addition of sewage, it showed progressively lower dehydrogenases activity.