Effect of aeration intensity on the nitrogen and phosphorus removal performance of AOA membrane bioreactors

The ability of simultaneous phosphorus and nitrogen removal of sequencing batch membrane bioreactor run in anaerobic/oxic/anoxic mode(AOA MBR) was examined under three aeration intensities[2.5,3.75 and 5.0 m3·(m2·h)-1].The results showed that the averaged removals of COD were over 90% at different aeration intensities.And the higher aeration intensity was,the more ammonia nitrogen removal rate achieved.The removal rates of NH+4 under the three aeration intensities were 84.7%,90.6% and 93.8%,respectively.Total nitrogen removal rate increased with the increasing aeration intensity.But excessive aeration intensity reduced TN removal.The removal rates of TN under the three aeration intensities were 83.4%,87.4% and 80.6%,respectively.Aeration intensity affected the denitrifying phosphorus ability of the AOA MBR.The ratio of denitrification phosphorus removal under the three aeration intensities were 20%,30.2% and 26.7%,respectively.