Optimization And Experimental Study On Advanced Treatment Process Of TZ Petrochemical Wastewater

China is short of water resources and the surface water pollution is more serious than developed countries.Industrial sewage accounts for a large proportion in surface water,and its pollution level and discharge amount directly affect the surface water environment.In the process of petroleum refining and processing,the composition and content of pollutants in industrial wastewater produced by different production processes are also different.With the upgrading of the petrochemical industry,sewage treatment is becoming more and more complex,and there are more and more types.It is necessary to upgrade the sewage treatment process while upgrading the industry,so that the industrial sewage can achieve the purpose of“sewage reuse”after a certain process.Thereby saving water and improving the utilization of water resources.This paper studies the various steps of the oily wastewater treatment process of TZ Petrochemical Company,and deeply analyzes the treatment effect of wastewater treatment and reuse process.Due to the normalization of the inflow of oily sewage from TZ Petrochemical Company,the qualified rate of COD is relatively low,which has a great impact on the treatment of oily series wastewater.Therefore,the Fenton oxidation method was used for experimental analysis.The effects of various main factors on the COD removal efficiency of the secondary sedimentation tank were studied by orthogonal experiment and single factor experiment,and the optimal process conditions were determined.Through orthogonal test analysis,it is concluded that the maximum effect of COD on the effluent from the secondary sedimentation tank is the amount of hydrogen peroxide added,followed by the Fe²⁺dosage and the initial pH value of the wastewater,and the reaction time has the least influence.The optimal COD removal effect was as follows:the initial pH was 2,the hydrogen peroxide dosage was 25 mmol/L,the Fe²⁺dosage was 15 mmol/L,and the reaction time was 120 min.The single factor optimization test can be used to obtain the optimal reaction conditions for the Fenton reagent to deeply treat the effluent from the secondary settling tank:pH value is 3,the optimum dosage of hydrogen peroxide is 25mmol/L,and the optimum dosage of Fe²⁺is 15mmol./L,the reaction time is 120min.Under the conditions of this test,the removal rate of COD can reach 57.06%.It is technically feasible to use the Fenton method to carry out advanced treatment of the effluent from the secondary settling tank.The removal rate of COD is about 55%.If Fenton method+PAM is adopted,the removal rate can be increased to 70%.The treated effluent is effectively degraded,and the subsequent process can ensure that the effluent reaches the standard.The effluent from the secondary settling tank is less biodegradable.Increasing the degradation of COD by the fluidized bed Fenton oxidation equipment has the advantages of low investment cost,easy operation and maintenance,and high efficiency.It is only used when the COD value of the influent water of the device is too high,which reduces the subsequent process load and makes the sewage discharge meet the standard.When the water inflow index is good,the bypass is used to reduce the running cost.