Study On Deep Treatment And Reuse Of Effluent In Puguang Purification Plant

Water shortage is a common problem in oil development,but a large amount of unusable sewage will be produced in the operation of oil fields.In order to respond to the requirements of national water-saving and emission-reduction policies and cope with the current situation of water shortage,puguang purification plant has established a recycling system for the production sewage,but the total phosphorus and microbial content still exceed the industrial circulating water control standards.In this paper,through the analysis of the status quo of external drainage water and circulating sewage in puguang purification plant,the methods of phosphorus removal and bacteria removal for external drainage were optimized,as well as the methods of phosphorus removal and bacteria removal for circulating water drainage sewage,and the experiments and application analysis of phosphorus removal and bacteria removal were carried out.Based on the analysis of the status quo of water quality after the pretreatment of the reuse system,the reason why the total phosphorus in the external drainage water exceeds the standard is that the maintenance wastewater contains high phosphorus,and the total bacteria exceeds the standard is that the sterilization link is not considered in the SBR process design,so the total number of bacteria cannot be effectively controlled.Based on the analysis of the current situation of circulating water pollution,the phosphorus in circulating water pollution mainly comes from the phosphoric acid root brought by boiler dosing and the organic phosphorus brought by circulating water reagent.The phosphorus removal by effluent water was studied by chemical method,physical membrane filtration and biological method.The optimal phosphorus removal agent by chemical method was determined to be agent C,with the proportion coefficient of agent C added being 1.7:1,and the mass concentration of compound agent m-1 added being 0.05%,the removal rate of total phosphorus in sewage reached 98.8%.The total number of bacteria in effluent water was controlled by chemical method,physical membrane filtration and biological method.The effect of chemical sterilization is ideal.SBR process can control effluent bacteria effectively.Membrane filtration method is efficient and stable in sterilization,and its operation cost is low.It is suggested that the combined process of chemical sterilization and membrane filtration to control the total number of bacteria in reclaimed water.Through laboratory tests,the processes of phosphorus removal and sterilization for external drainage water were determined to be the ultrafiltration ceramic membrane system and the integrated process of chemical phosphorus removal and sterilization.In order to remove phosphorus from circulating wastewater,the high-efficiency sedimentation tank+V filtration process was simulated by laboratory experiments.PAC,PAM and FeCl3 were used to remove TP from wastewater,and the requirements of reuse were met.Chemical agents+coagulation tank+security filter+SiC membrane fine filtration process was used on site to conduct phosphorus removal experiment,and the phosphorus content in the effluent water was less than 0.5mg/L.Based on the experimental results,two technical schemes of flocculation+silicon carbide membrane filtration and flocculation+silicon carbide membrane filtration were compared.According to the analysis of the operation results,the total phosphorus content of the process effluent is between 0.11 and 0.21mg/L,which meets the discharge standard requirements.