Affecting factors and control strategies of the competition of phosphorus accumulating organisms (PAO) and glycogen accumulating organisms (GAO) in enhanced biological phosphorus removal

Glycogen accumulating organisms (GAO) compete the carbon substrates with phosphorus accumulating organisms (PAO), which potentially lead to the upsets and deterioration of the EBPR process performance. To optimize the EBPR activated sludge system effective and robust, the integrated affecting factors consisting of temperature, carbon sources, pH, other minor factors and their interaction effect should be focused on the competition of PAO and GAO in EBPR systems. To improve the EBPR system stable and reliable, the control approaches should be matched to favor development of PAO and to suppress GAO. Hence, the factors affecting the competition of PAO and GAO in EBPR activated sludge system and relevant implementation of control strategies are discussed in this paper.