Effects of nitrogen and phosphorus removal in sequencing batch membrane bioreactor with different modes

Laboratory scale experiments were conducted to compare the removal efficiency of nitrogen, phosphorus and COD_cr in simulated domestic wastewater using two sequencing batch membrane bioreactors (SBMBR) operated in anaerobic aerobic (AO) and anaerobic aerobic anoxic (AOA) mode. And the changing concentrations of different stages in two modes were detected through sequencing cycle test. Results obtained from this study demonstrate a good performance of MBRs regarding COD_cr and the removal rates are both 92% on average. The ammonium nitrogen, total nitrogen (TN) and total phosphorus (TP) removal rates could be maintained at 94.1%, 78.9% and 58.6% respectively in AO MBR system, and at 96.9%, 81.9% and 78.3% respectively in AOA MBR system. Results reported here indicate that the AOA MBR may become an effective treatment process to meet the effluent discharge, especially for stringent regulatory requirements for TP.