Hydrolysis of condensed phosphates during aerobic biological sewage treatment

Abstract

In a domestic sewage, the concentrations of orthophosphate and inorganic condensed phosphate varied widely during a 24-hr period. The condensed phosphate concentration was especially variable, increasing from 1 to 17 mg P/l during a 4-hr span. This increase coincided with an increase in the concentration of ABS. In the settled sewages sampled, approximately half the phosphorus was in the form of condensed phosphates. Treatment at activated sludge and trickling filter installations affected the hydrolysis of a portion of the incoming condensed phosphates. The extent of hydrolysis was variable, but in general, approximately half the condensed phosphates in the settled sewage was converted to orthophosphate during aerobic biological treatment.