Treatment of oil refining industry wastewater with membrane-bioreactor system

摘要

In this paper the operability and optimal operation conditions for oil refining industry wastewater treatment with submerged membrane-bioreactor (MBR) system were studied. The oil refining industry wastewater pretreated by two-stage floatation was treated with an anaerobic-aerobic integrated MBR system in pilot-scale. After the activated sludge was cultured and trained for about 20-30 d with an increasing wastewater feed time and quantity and a decreasing quantity of added nutrient substances, the MBR system ran stably. During the stable operation period, pH of wastewater in the MBR maintained between 7.5 and 8.0, MLSS between 6000 and 8000 mg/L, DO at about 2 mg/L in aerobic zone and at about 0.2 mg/L in anaerobic zone, and SVI between 90-150. The removal efficiency of NH_3-N, COD_(Cr), phenol and oil was 92%, 92%, 99% and 67%, respectively; the effluent quality reached the design requirement.