The operation of MBR consists of two phases. The 1st phase (day0–95) was a start-up period to allow the biomass within the sys-tem to build up and be ready for a research in both anoxic andaerobic reactors until we achieved steady reactor performance interms of organic and nitrogen removals. During this period, sludgere-circulation was not performed. The 2nd phase (from day 96 to500) was continuously conducted after the 1st phase. In this phase,we controlled MLSS concentration in aerobic reactor with sludgere-circulation to study about the removals of emerging contam-inants in the reactors (from day 212 to 500). Leachate used forthe experiment was prepared by mixing fresh leachate collectedfrom solid waste collection truck and stabilized leachate obtainedfrom a leachate storage pond. The fresh and stabilized leachate wasmixed at a mixing ratio of 1:4 (v/v) to represent average charac-teristics of leachate of both operating and closed landfill cells. Inpreparation, water in the system would remain constant of water