[Comparisons of simultaneous phosphorus and nitrogen removal in sequencing batch membrane bioreactors]

Two SBMBRs run in AO and A2O mode were operated in parallel to compare their ability of simultaneous phosphorus and nitrogen removal. The results showed that the removals of COD and ammonium nitrogen were averaged over 90% and 95%, respectively. A2O MBR has the stronger anaerobic phosphorus release ability; its SPRR30 outdoes 47.5% compared to AO MBR. SPUR30 of A2O MBR was lower which may attribute to the higher effluent TP content. The ratio of DPAO was enhanced 57% compared to AO MBR. And when nitrate as the only electron accepter, the phosphorus uptake mass with unit electron transfer was 30% higher in A2O MBR. This two factors lead to the stronger denitrifying phosphorus removal ability of A2O MBR. Furthermore, the membrane fouling was mitigated in A2O MBR though the aerobic time was half to that of AO MBR. The membrane filter function made SBMBR's effluent free of the sludge settlement ability.