Investigation of membrane-aerated biofilm reactor (MABR) for the treatment of crude oil wastewater from offshore oil platforms

Membrane-aerated biofilm reactor (MABR) was designed to treat oilfield produced wastewater from offshore oil platform. The effects of suspended solids (SS) of influent, intramembrane air pressure, and feed flow velocity on chemical oxygen demand (COD), oil, and ammonia nitrogen (NH4+-N) removals were investigated through a 160-d process study. The results indicate: (a) high influent SS resulted in the formation of a barrier layer containing insoluble SS on the outside surface of biofilm which significantly reduced the mass transfer of NH4+-N and organic substrates from wastewater to the biofilm; (b) under the condition of feed flow velocity of 0.01 m/s, with the increase in intra-membrane air pressure, the oxygen permeate flux of hollow fiber membrane was enhanced and NH4+-N removal efficiency at 0.12 MPa was up to 95%; (c) under the condition of intra-membrane air pressure of 0.08 MPa, with the increase in flow velocity, the performance of MABR was significantly enhanced, the best removal efficiencies of COD, oil, and NH4+-N reached 60.3, 80, and 95%, respectively, at the feed flow velocity of 0.05 m/s.