A pilot-scale combined system composed of anaerobic digenstion, membrane bioreactor (MBR) and Electro-Catalyzed oxidation processes has been set up to treat the leachate from municipal solid waste (MSW) transfer station. System performance was evaluated by ammonia and chemical oxidation demand (COD) removal . Results showed that 97% of ammonia was removed by MBR, and the elimination of COD was mainly completed in anaerobic process and MBR with a total removal of 99%. In addition, the analysis of microbial communities in the MBR, carried out by clone library and denaturing gradient gel electrophoresis (DGGE) of the 16S rRNA genes, indicated a highly diverse bacterial community and the enrichment of N-cycling bacteria.