The external carbon source to each stages of A2/O process for simultaneously nitrogen and phosphorus removal

A novel method which could simultaneously solve the insufficient of carbon source and maximize the utilized of carbon source was investigated in this study. As methanol, glucose and ethanol were taken as respectively carbon sources for the A2/O system, getting the ethanol was the best one on simultaneously the nitrogen and phosphorus removed. Total nitrogen (TN) and total phosphorus (TP) removal efficiencies were 78.23% and 78.18%, and the time of NOX-N removed was 20min.The study about the effect on the external carbon source shown that when dosing method was 0:1:2, the external carbon source concentration was 400mg/L and nitrate recycling ratio was 250%, the A2/O system on simultaneously total nitrogen (TN) and total phosphorus (TP) removed ran well. At this point, phosphorus concentration in anoxic was lower than phosphorus concentration in the influent, which indicated the denitrifying phosphorus accumulating organisms (DPAOs) accumulated in anoxic zones. The removal efficiencies of TN, NH3-N and TP were 82.36%, 96.67% and 92.18%, respectively. The effluent concentrations were 11.43mg/L,4.1mg/L and 0.45mg/L respectively, which reached the type A standard GB18918-2002 level.