Study On High Organic Wasterwater Treatment By Electrochemistry And Biochemistry

High concentration organic wastewater is one of the main source of water pollution of the environment, some of difficult degradation high concentration organic wastewater often needs to deal with the physical and chemical pretreatment before using biological method, therefore, it is necessary to develop high efficient physical and chemical pretreatment technologies for high concentration organic wastewater.The middle treatment of emulsion wastewater is chosen as the research object of one enterprise in the Shanghai Chemical Industry Area. This research study on micro-electrolysis and electro-Fenton combination technology to pretreat high concentration organic wastewater and used biochemical method to treat the electrochemical pretreated water. The research contents are as follows:studying the factors and optimum operating parameters of micro-electrolysis and electro-Fenton methods; studying the optimization treatment effects and stability analysis for high concentration organic wastewater of micro-electrolysis and electro-Fenton method; starting hydrolysis acidification tank and aerobic tank; studying on treatment effect of hydrolysis acidification and aerobic activated sludge process for electrochemical treated wastewater.In this study, choosing cast iron and carbon particles as the micro-electrolysis filler, choosing cast iron plate as the electric Fenton plate. Using the above methods to pretreat the high concentration organic wastewater respectively and analyzing by single factor test and orthogonal test. The optimum operating parameters are as follows:for micro-electrolysis:the initial pH is 3, reaction time is 90 min, the iron-carbon mass ratio is 1:1, COD removal rate is up to 32.41%, B/C ratio increased from 0.24 to 0.42, the primary and secondary order degree of influence is pH> iron-carbon mass ratio> reaction time, the micro-electrolysis method has good treatment effect for the difficult biochemical organisms and hazardous substances in high concentration organic wastewater. for electro-Fenton:the initial pH is 2, reaction time is 180 min, the plate spacing is 20mm, the current density is 40 mA · cm-2, H2O2 dosing volume is 5%; COD removal rate is up to 67.11%, BOD5 removal rate can up to 49.3%, the primary and secondary order degree of influence is pH> current density> reaction time> H2O2 dosage, the electro-Fenton method has high removal efficiency for organic matter in high concentration organic wastewater.In order to reduce the COD and the load for subsequent biological treatment, the study presents micro-electrolysis and elector-Fenton method to pretreat the high concentration organic wastewater. The micro-electrolysis in the optimal conditions treated wastewater is adjusted the pH to 2, then turned into the electro-Fenton apparatus which also in the optimal conditions. After above treatment processes, the COD removal rate can reach to 80%, the COD of effluent is reduced to 1000 mg/1, the B/C is increased from 0.2 to 0.7, the biodegradation has been significantly improved. The analysis of the four acting phases in micro-electrolysis and electro-Fenton:acid precipitation, micro-electrolysis, electro-Fenton, coagulation and sedimentation can draw the conclusion that COD removal mainly rely on the role of micro-electrolysis and electro-Fenton.In this study, hydrolysis and acidification combined aerobic activated sludge process is used to treat electrochemical pretreatment effluent. When the reaction time of hydrolysis and acidification is 32-48 h, the COD removal efficiency can be stabilized at above 70%and the effluent COD is 500 mg·L-1; When the reaction time of aerobic activated sludge is 16～24 h, the COD removal efficiency can be stabilized at above 85% and the final effluent COD is remained at 100 mg·L-1 or less, the effluent can achieve the integrated wastewater discharge standard GB 89788-1996.