Method of Treating Wastewater and Producing an Activated Sludge Having a High Biopolymer Production Potential

A method or process is provided for treating wastewater and producing a polyhydroxyalkanote (PHA)-storing biomass. The method or process entails biologically treating wastewater and in one process a filamentous biomass is selected and caused to proliferate so as to dominate an activated sludge. The filamentous biomass is utilized to treat the wastewater and to remove contaminants therefrom. As a part of this process, there is provided an enhancement for PHA production potential in the said biomass. This entails enhancing the PHA production potential of the filamentous biomass by subjecting the biomass to alternating feast and famine conditions where under feast conditions more biodegradable organic substrate is available to the filamentous biomass than under famine conditions. In another process, wastewater is treated with an activated sludge. The wastewater is treated in a main stream and as a part of the process, the activated sludge and biomass contained therein is concentrated and directed to a side stream. In the side stream, at least a portion of the enhancement for PHA production potential in the biomass from the process is carried out. In one particular process, the activated sludge and the biomass contained therein is concentrated by a separator and the concentrated biomass is directed to a side stream and subjected to famine conditions.