Review on the Factors Affecting the Enrichment Culture of PAOs and GAOs

Abstract:

At present, the enhanced biological phosphorus removal (EBPR) process has been widely used for its cost-effctive, but a type of bacteria-glycogen accumulating organisms(GAOs) which can compete with phosphate accumulating organisms (PAOs) and lead to the deterioration of EBPR. There have been many studies about PAOs-GAOs, the conclusions have both convergences and contradictions however, so it is necessary to discuss and analysis. According to the relevant reports at home and abroad in recent years, the factors affecting the enrichment culture of PAOs and GAOs are expounded, including P/C ratio, carbon type, temperature, pH value which are more important in the system. In addition, sludge age, dissolved oxygen, etc. also played a role for the competition of PAOs and GAOs. In EBPR system, denitrifying phosphate accumulating organisms and denitrifying glycogen accumulating organisms which also have impact on the enrichment of PAOs and dephosphorization were observed in anoxic condition. Finally, the future direction of the EBPR system for the future is viewed.