Evaluation of performance and carbon reduction of intermittent aeration membrane bioreactor

The performance of three pilot scale intermittent aeration membrane bioreactors (IAMBRs) with different operating phases was evaluated over a long-term operation. Moreover, the effects of different effluent strategy on the carbon emission and economic cost of the reactor were analyzed. The results show that the average removal rate of organic matter and total phosphorus (TP) was stably above 90 %. However, the single-point continuous inflow led to the uneven distribution of carbon source and nitrogen in the anoxic section, which inhibited the denitrification process. Therefore, the short-term aeration during phase II was conducted to enhance the denitrification, and the result showed that pre-aeration significantly improved the degradation efficiency of NH3-N. More importantly, the carbon emission of IAMBR process (Device 1 and 3 was 0.695 kg/m3 and 0.657 kg/m3, respectively) was lower than that of traditional activated sludge process, MBR process and AAO-MBR process. This study demonstrated that in the areas with low effluent quality requirements, the intermittent aeration operation with gravity effluent could be a better selection in reducing the operating costs and indirect carbon emissions.