Patent ID: 8187462

Claim:
A method of treating wastewater and producing polyhydroxyalkanoates (PHAs) by selecting glycogen accumulating organisms (GAOs) having a high PHA production potential in a mixed culture biomass, the method including: providing wastewater containing volatile fatty acids (VFAs) and a mixed culture biomass; selecting a GAO dominated biomass and causing the GAOs to proliferate and dominate over other microorganisms in the biomass by: subjecting the biomass to alternating anaerobic and aerobic or anoxic treatment, wherein the alternating anaerobic and aerobic or anoxic treatment produce the GAO dominated biomass having GAOs with relatively high levels of intracellularly stored glycogen; providing substantially more VFAs to the biomass during anaerobic treatment than during the aerobic or anoxic treatment such that during the anaerobic treatment, the GAOs in the GAO dominated biomass consume the VFAs and the intracellularly stored glycogen to produce PHA; providing the VFAs to the biomass during anaerobic treatment at a ratio of at least 0.08 g of VFA per 1 g of total suspended solids (TSS) provided; and accumulating the PHA in the GAO dominated biomass.