Study on performance characteristics of carbon membrane-aerated biofilm reactor treating municipal wastewater

Abstract

A carbon membrane-aerated biofilm reactor was developed to treat municipal wastewater. Tests were conducted to investigate oxygen transfer ability of carbon membrane, the bacteria adhesion and reactor's set-up performance. The optimum parameters were determined in terms of intra-membrane pressure, COD and nitrogen ratio and hydraulic retention time(HRT). The results showed that compared with that of other hollow fibres, bacterial suspended exhibited a high degree of adhesion onto carbon membrane and that oxygen transfer coefficient of carbon membrane was 0.36 m/h, so that it was feasible to serve as both biofilm carrier and aerator. NH44-N removal, denitrification and COD removal efficiency could reach 95%, 92% and 88%, respectively, under the conditions of intra-membrane pressure of 0.025 MPa, carbon nitrogen ratio of 5 and HRT of 8 h, and effluent quality could be up to A standard in the national discharge standard of pollutants for municipal wastewater treatment plant (GB 18918-2002). Furthermore, the system displayed better resistance to shock loads.