A process of intermittently cyclic activated sludge-membrane bioreactor (ICAS-MBR) was developed to enhance the performance of biological phosphorus removal (EBPR), which was constructed under sequencing anoxic/anaerobic/aerobic condition. The performance between ICAS-MBR and conventional anoxic/aerobic-membrane bioreactor (A/O-MBR) in terms of phosphorus removal, nitrification performance and microbial aspects were investigated in this study. The experimental results indicated that the phosphorus removal efficiency in ICAS-MBR process increased from 65% to 83% when compared with A/O-MBR. It was also found that the COD removal efficiencies of the two processes were over 94%, and NH(4)(+)-N and TN average removal efficiencies were 96% and 69% in ICAS-MBR and 96% and 78% in A/O-MBR, respectively. Furthermore, micrographs observation obtained confirmed the succession and diversification of microorganisms in the two systems followed a similar regularity. (C) 2009 Elsevier Ltd. All rights reserved.