Flocculation and Ultrafiltration Combined Process Used to Treat Oilfeild Wastewater

In order to solve pretreatment problem of reverse osmosis membrane methods which were used for the secondary effluent from the oilfield sewage,the combined process of flocculation and ultrafiltration was used for the advanced treatment of the secondary effluent from the oilfield sewage,and the removal effect of flocculation,ultrafiltration and the combined process of the two on TOC and turbiditywere studied,respectively.The results showed that with flocculation only,the removal rate of turbidity was 90.6%while that of TOC was below 20%on condition that the optimal dosing quantity of PAC was 40 mg/L and PAM was 0.5 mg/L.With the combined process of flocculation and ultrafiltration,the removal effect of TOC and turbidity reached above 98%and 30%,respectively,which could not only improve the quality of the treated water but also produce a remarkable effect on the increase of water flux and the reduction of membrane fouling.The product water silt density index(SDI) of the combined process of flocculation and ultrafiltration was less than 3,which could meet the requirements of reverse osmosis feed.