Review on the Microbiological and Biochemical Characteristics of Enhanced Biological Phosphorus Removal System

The microbiological and biochemical characteristics of enhanced biological phosphorus removal (EBPR) process was summarized. With respect to the microbiology, the competition and relationship among the main microbes in the system, including poly-phosphate accumulating organisms (PAOs), glycogen accumulating organisms (GAOs) and denitrified PAOs (DPAOs) were concluded. A wide variety of PAOs were separated from the EBPR system and the Accumulibacter was considered a typical PAO, existing in all kinds of EBPR systems. There was still controversy concerning the relationship between PAOs and GAOs and the classification of DPAOs. With respect to the biochemistry, the relevance between the intracellular polymers and the metabolic function was concluded. The reducing power in the anaerobic phase was provided both by the TCA circulation and the glycolysis process, influenced by the population structure and experiment condition. The degradation of glycogen was different when the bacterial strain was different and the glycogen was the regulator of the redox equilibrium in the cell. The composition of poly-β-hydroxyalkanoates (PH As) was determined by the organic substrate, and when propionic acid was the substrate, four monomers of PHAs could be detected. The power used in the anaerobic P-releasing was derived from the decomposition of polyphosphate and glycogen, while the amount of power needed was influenced by experiment condition.