Experimental Study On Removal Of Organic Compounds In Electroplating Deoiling Wastewater

As the rapid development of manufacturing,with supporting the same rapid development of the electroplating industry,electroplating industry,a wide range of enterprises,large-scale,large differences in the process,resulting in electroplating industry wastewater has a complex composition,large amount of waste water,serious pollution Features.Shenzhen,Guangdong Province,although China's high-end electroplating business gathering of the leading,but its treatment of electroplating wastewater is still in the low level of equipment,poor environmental protection facilities,electroplating wastewater treatment technology and equipment upgrades to be resolved.This paper chooses the degreasing wastewater of a typical metal electroplating factory in Shenzhen as the raw water of the test,and explores the effect of the high-level oxidation + biochemical module on the removal of organic matter.Test raw water quality is as follows:pH=13.1-13.5,SS=53-55mg/L,COD=200-2500mg/L,BOD=340-440mg/L,B/C=0.17-0.19.According to the actual situation of wastewater,two kinds of methods,namely Fenton oxidation method and O₃/H₂O₂ system oxidation method,were selected from a variety of advanced oxidation methods,and these two methods were compared to the treatment effect of electroplating and degreasing wastewater,Preferred as a follow-up biochemical treatment stage of the pretreatment method;biological treatment method is selected submerged MBR membrane bioreactor.The optimum conditions of Fenton oxidation are as follows:the dosage of hydrogen peroxide is 1500mg/L,the dosage of H₂O₂/Fe2+ is 4:1,the pH value is 3.0,and the reaction time is 30min.Under these conditions,COD removal rate of 89.76%,biodegradable B/C from 0.17 before the reaction to 0.31.The optimum conditions of O₃/H₂O₂ oxidation were as follows:the dosage of ozone was 2.5ml/min,the molar ratio of O₃/H₂O₂ was 5:1,the pH value was 8.0,and the reaction time was 90min.Under these conditions,the removal rate of COD was 86.4%,and the value of B/C increased from 0.17 to 0.45 before reaction.Compared with Fenton oxidation method,O₃/H₂O₂ system is better for the degradation effect of electroplating wastewater.In the case of the best process parameters,the latter can improve the biodegradability of wastewater to 0.45,compared to the former 0.31,more conducive to follow-up treatment.At the same time,O₃/H₂O₂ oxidation method solves the problem of large amount of residual sediment in Fenton oxidation method.Based on the analysis of the advantages and disadvantages of the two oxidation methods,O₃/H₂O₂ oxidation method can be used as the pretreatment method.The optimum process parameters of MBR membrane bioreactor are as follows:hydraulic retention time is 10h,the aeration rate is 3.0L/min,the ratio of carbon to nitrogen is 2:1,and the suitable temperature range is 15-30?.Under the condition of the process parameters,the COD removal rate of the effluent of the reactor is stabilized above 80%,and the COD concentration of the effluent can be kept below 50mg/L.