Integrated nitrogen removal biofilter system with ceramic membrane for advanced post-treatment of municipal wastewater.

The pre-denitrification biofilm process for nitrogen removal was combined with ceramic membrane with pore sizes of 0.05-0.1 mu m as a system for advanced post-treatment of municipal wastewater. The system was operated under an empty bed hydraulic retention time of 7.8h, recirculation ratio of 3, and transmembrane pressure of 0.47bar. The system showed average removals of organics, total nitrogen, and solids as high as 93%, 80%, and 100%, respectively. Rapid nitrification could be achieved and denitrification was performed in the anoxic filter without external carbon supplements. The residual particulate organics and nitrogen in effluent from biofilm process could be also removed successfully through membrane filtration and the removal of total coliform was noticeably improved after membrane filtration. Thus, a system composed of the pre-denitrification biofilm process with ceramic membrane would be a compact and flexible option for advanced post-treatment of municipal wastewater.