Waste Water Treatment Process Scheme And Automatic Control In NC Electroplating Industrial Parkcirculating System

With the rapid development of industry,the number of industrial areas in China is growing rapidly,and the task of industrial pollution control is becoming more and more onerous.The electroplating waste water in electroplating park is complicated and difficult to deal with,so it must be treated separately before discharge is allowed after reaching the discharge standard.This study mainly studies the comprehensive sewage treatment process scheme of NC Electroplating Industrial Park,optimizes the scientific and reasonable treatment process,and carries on the process design,which provides technical support for the construction of the sewage treatment plant in NC Electroplating Industrial Park.In this paper,the electroplating waste water treatment project in NC Electroplating Industrial Park is taken as the research object,and the treatment process of electroplating waste water in NC Electroplating Industrial Park is determined by comparison,and the treatment effect of the main treatment process units is verified by a small scale test.The research contents include the analysis and determination of the quantity and quality of electroplating waste water;the selection and analysis of treatment process scheme;the experimental verification of the treatment effect of the main treatment process unit;the design and calculation of the treatment process,the analysis and discussion of the operation effect.According to the planning of NC Electroplating Industrial Park and analogy with other electroplating industrial zones,the treatment scale was determined to be 1200m3/d;according to the measured water quality of existing enterprises in the park and referring to the water quality of other electroplating enterprises,the CN-28.65mg/L;chromium-containing waste water Cr6+=35.3mg/L,the total zinc=15.8mg/L,the total copper=15.64mg/L,the total nickel=15.71mg/L,the total zinc in comprehensive waste water was 15.8mg/L,the total copper was 15.64mg/L,and the total nickel was 15.71mg/L.The effluent implements the discharge Standard of Electroplating pollutants(GB21900-2008).According to the water quality characteristics and effluent quality requirements of the electroplating industrial park,cyanide-containing waste water and chromium-containing waste water were pretreated respectively,and then treated with comprehensive waste water.The pretreatment of chromium-containing waste water was carried out by chemical reduction method,the cyanide-containing waste water was pretreated by chlorine dioxide oxidation method,and the comprehensive waste water was treated by flocculation,precipitation and high efficiency filtration.The results of cyanide removal by chlorine dioxide oxidation showed that when the ratio of chlorine dioxide to CN-was 4:1,the residual concentration of CN-was 0.29mg/L,and the treatment effect was not improved obviously when the ratio of chlorine dioxide to CN-was 4:1.The results of chromium removal by reduction method show that when the ratio of sodium pyrosulfite to Cr6+is 4:1,the residual concentration of Cr6+is 0.18 mg/L,and the treatment effect is not improved obviously when the ratio of sodium pyrosulfite to Cr6+is 4:1.Verification Test of flocculation and precipitation of Comprehensive Waste water The results show that when the dosage of PAM is 1 mg/L and the dosage of COD is 2.mg/L,the residual concentration of COD is 80 mg/L.The results of the test run after the completion show that the effluent indexes of the WWTP in the NC electroplating industrial park are as follows:total chromium=0.5 mg/L,total cyanide(in CN-)=0.26 mg/L,total nickel=0.43 mg/L,total copper=0.42 mg/L,total zinc=1.3 mg/L,reaching the design water quality requirement.The pretreatment of chromium-containing waste water is carried out by chemical reduction method,the cyanide-containing waste water is pretreated by chlorine dioxide oxidation method,and the comprehensive waste water is treated by flocculation,precipitation and high efficiency filtration process,which is suitable for the treatment of waste water from NC Electroplating Industrial Park.The treated water quality has reached the discharge Standard of Electroplating pollutants(GB21900-2008).The construction of sewage treatment plant in the park is of great significance to the protection of the local environment.