Research on the Optimal Operation of Inverted A2/O&MBR Process for Rural Domestic Sewage Treatment

A new integrated device—inverted A2/O–MBR process for rural domestic sewage treatment was designed and investigated in this study. The device consisted of three components orderly referred to the anoxic zone, anaerobic zone and aerobic zone where a MBR membrane group was arranged. Results showed that the device was favorable to treat rural domestic sewage. Optimal influent percentage of influent to anoxic zone was 70%, with TN, TP removal ratio approaching to 69% and 89%. Reduction of NH4+-N and TN enhanced with the increase of sludge age, but that of TP decreased. 15d was determined to be the best sludge age for simultaneous removal of NH4+-N, TN and TP. Moreover, when DO was 3.0mg/L, NH4+-N, TN and TP reduction reached up to 96%, 70% and 88% respectively. These data verified the good performance of the integrated system, and the quality of effluent could well meet the direct emission standard of Outdoor Drainage Design Specification in China (GB50014-2006) (edition 2014).