Performance characteristics of a hybrid membrane pilot-scale plant for oilfield-produced wastewater

Oilfield produced wastewater is a complicated system containing high levels of oil, SS (total suspended solid), sulfide, reductive substances and salinity, etc. The current treatment process operating in Daqing oilfield cannot treat the oily wastewater to satisfy the discharging standard to surrounding environment or the water quality for injection into low-osmosis oilfield. In this paper, a pilot-scale plant involving aeration tank, air floatation, sand filter and UF has been designed and performance characteristics of the hybrid process have been studied for treatment of the oily wastewater. Operation results show that this process can largely reduce the oil, SS contents in the oily wastewater to less than 0.5 mg/L, 1.0 mg/L, respectively, and the concentration levels of Fe, reductive substances, sulfate reduction bacteria (SRB), metatrophic bacteriaTGBand iron bacteriaIBcan also meet the required standard for discharging or injection water.