PRODUCTION OF POLYHYDROXYALKANOATE DURING TREATMENT OF LOW-PHOSPHORUS CONTENT WASTEWATER

To evaluate whether poly-β-hydroxyalkanoate (PHA) production and wastewater treatment could be combined in a single biological process, a bench-scale sequencing batch reactor was operated with sequential anaerobic and aerobic stages and removal of excess sludge at different stages of treatment. The reactor treated synthetic wastewater with a high organic and low nutrient content, simulating industrial wastewater. COD removal efficiency was over 90% in all cases. PHA accumulation was significant, although it did not appear to be induced by oxygen limitations during the anaerobic stage. Sphaerotilus natans was apparently the dominant PHA-accumulating organism at the end of each reactor run and corresponded to a PHA accumulation of 16-20% of the total dry cell mass. Before S. natans dominated the reactors, PHA accumulation was about 17% when biomass was removed at the end of the aerobic stage and 6.6% when sludge removal was also during the anaerobic stage.