外置式超滤膜生物反应器处理油田废水

Treatment of Oil Field Wastewater with Recirculated Ultrafiltration Membrane Bioreactor

采用外置式超滤膜生物反应器处理油田废水，废水中的有机物被生物接触氧化池填料上形成生物膜的微生物降解，然后通过中空纤维超滤膜进行过滤，出水中油的质量浓度在1mg／L以下，悬浮物的质量浓度在3mg／L以下。考察了细菌的筛选、生物膜的培养驯化及压力、温度等对膜通量的影响。实验结果表明，筛选出的3株高效原油降解菌有很好的除油效果；生物膜经培养驯化成熟后，生物接触氧化池内细菌浓度为1×10^6个／mL；膜通量随压力和温度的适当提高而增加，适宜的操作压力为0．08MPa，温度为20～28℃。分别用超滤水反冲洗、稀碱、稀酸、杀菌剂（如NaClO溶液）和清水冲洗被污染的超滤膜，可使膜通量恢复到新膜的98％以上；在生物除油工序后增加沉淀池，膜污染可减少约7．77％。

Oil field wastewater was treated with recirculated ultrafiltration membrane bioreactor （RUMBR）. Organic substances in the wastewater were degraded by biofilm formed on the carrier in biological contact oxidation pond, and then the wastewater was filtrated by hollow fiber ultrafiltration membrane. The mass concentration of oil and suspended substance in the effluent is less than 1 mg/L and 3 mg/L respectively. Strain screening and biofilm cultivation were carded out. The effects of pressure and temperature on membrane flux were investigated. The results show that：3 kinds of strains have good oil-removing effects; The bacterial concentration in biological contact oxidation pond can reach 1 × 10^6/mL; The membrane flux is increased with the appropriate increasing of pressure and temperature, and the befitting operating pressure is 0.08 MPa and the temperature is 20 - 28 ℃. The membrane flux can be recovered over 98% after the fouled ultrafiltration membrane is treated by back flushing with treated water and flushing with dilute base, dilute acid, germicides （such as NaClO）and treated water. Setting a flow tank behind the biological oil-removing unit can reduce the membrane fouling by about 7.77%.