[Improvement of denitrifying dephosphatation in an anaerobic/anoxic sequencing batch reactor and its stability]

An anaerobic/anoxic sequencing batch reactor (A/A SBR) was conducted to investigate the conditions for screening and enrichment of denitrifying phosphorus removing bacteria (DPB). The results showed that, when the concentration of COD in influential of anaerobic stage, the concentration of NO3 -N in influent of anoxic stage and pH value were 300 mg/L, 50 mg/L and 7.0 respectively, DPB could become dominant populations quickly in the system in two-time feeding mode, and the reactor performed well for denitrifying phosphorus removal. The A/A SBR still performed well by shifting the system to one-time feeding mode. With the same concentration of phosphate of 20 mg x L(-1) in the influent, the phosphorus removal with adding the phosphate just before the beginning of anoxic stage proved to be better than that of directly increasing the phosphate concentration in the influent.