改进型A/O生物膜工艺在油田污水达标外排中的应用

Application of improved A/O biofilm process in meeting standard discharge of oilfield wastewater

河南油田某稠油联合站污水生化处理装置,由于生物膜结垢原因不能长期稳定运行,为减少生物膜结垢,在原有工艺基础上增加了弹性填料和内循环曝气器。在中试规模实验中,考察了改进型工艺对COD、氨氮、总氮、悬浮物的去除效果以及长期运行的稳定性能,并与现有工艺进行了比较。结果表明,改进型工艺出水COD、氨氮、总氮、悬浮物浓度分别为71.0、6.1、7.9和7.6 mg/L,为现有工艺的68.9%、141.9%、44.6%、57.6%。改进型工艺出水后续进行实验室规模絮凝沉淀处理,出水COD<60 mg/L,满足国家污水综合排放标准一级B要求。运行期间,好氧生物膜VSS/SS没有明显变化,说明改进型工艺生物膜结垢量大量减少,解决了现有工艺不能长期稳定运行的问题。

The wastewater biochemical treatment equipment in heavy oil field stations in the Henan oilfield has not exhibited long-term,operational stability due to biofilm scaling. Based on the original treatment process,elastic packings and an internal circulation aerator were added to decrease the amount of scaling. In the pilot test,chemical oxygen demand（ COD）,ammonia nitrogen,total nitrogen,suspended solids（ SS） removal efficiency,and long-term operation stability of the improved process were investigated. The results were as follows：the COD,ammonia nitrogen,total nitrogen,and SS concentrations of the improved process effluent were 71. 0,6. 1,7. 9 and 7. 6 mg / L,respectively,corresponding to 68. 9%,141. 9%,44. 6%,and 57. 6% of the original process effluent. Flocculation and sedimentation were used for advanced treatment of the improved process influent at a laboratory scale. The COD of the effluent was 60 mg / L,which reached the first level B criteria of the Integrated Wastewater Discharge Standard. The ratio of volatile suspended solids（ VSS） to SS of the biofilm did not noticeably change at run time. The result indicated that the amount of scaling on biofilm in the improved process was significantly reduced and the problem of long-term stable operation was resolved.