Results and discussion
3.1. Performance and removal efficiency of emerging contaminants in MBR treatment
The two-stage MBR treatment was operated in total of 500 days which the influent and effluent samples as well as emerg-ing contaminant concentrations were regularly monitored. During start-up period, MLSS concentration in the aerobic reactor was gradually increased from 2000 mg/l to more than 10,000 mg/l before sludge re-circulation started between aerobic and anoxic reactors. This was to help control biomass in system and the MLSS concentrations in the aerobic reactor were remained at 7–9 g/l where as those in anoxic reactor increased from about 3 to 7 g/l from day 150 to day 500 without losing the excess sludge from the system.