Biodegradation of two model estrogenic compounds in a preanoxic/anaerobic nutrient removing membrane bioreactor

Biological nutrient removal and the fate of two estrogenic compounds, bisphenol A (BPA) and 2,4-dicholorophenol (2,4-DCP) were studied using a sequencing anoxic/anaerobic-aerobic membrane bioreactor (SAM) which was fed with synthetic water and operated at SRT of 60 days. Total nitrogen (TN), total phosphorus (TP), COD, BPA and 2,4-DCP removal performances were evaluated. The SAM showed efficient COD removal (> 99%) throughout the period of operation. The TN and TP removal efficiencies were 74.3 ± 4.7% and 79.1 ± 7.2%, respectively. The removal efficiency of BPA and 2,4-DCP was 74.3% and 78% on average basis respectively. A mass balance of both compounds was derived considering the hydraulic characteristics of the system, mass flux due to air stripping and quantity of adsorbed compound discharged with daily excess sludge wastage. The results indicated that biodegradation was the major removal path way from the system contributing above 80% of removal.