Abstract
The mechanism of the luxury uptake of phosphorus by activated sludge was studied. An activated sludge process composed of an anaerobic zone followed by an aerobic zone removed almost five times more phosphorus than the conventional activated sludge process. In the anaerobic zone, most of the influent BOD was removed and orthophosphate was released. The amount of the released phosphate was found to be directly proportional to the amount of the removed BOD. For every two moles of glucose removed, one mole of orthophosphate was released; in case of acetate one mole was enough to cause the release of one mole of the phosphate. The removed glucose and acetate were stored in the sludge as glycogen and poly-j3-hydroxy-butyrate, respectively. In the aerobic zone, the released phosphate and the influent phosphorus were incorporated into the sludge and seemed to be stored as polyphosphates. Microorganisms in the anaerobic zone might utilize the polyphosphates as an energy source to incorporate BOD components and to synthesize storage compounds.
