The Research Of The Treatment For The Mixed Electroplating Wastewater With High Concentrations Of Organic Compounds And Chromium,nickel,copper

In this paper,the mixed electroplating wastewater of an industrial park in Nanchang is taken as the object of study,The characteristics of wastewater containhigh concentration organic matters and heavy metal ion,The pollutants and their concentrations are COD 1400 mg/L,total chromium 24.8 mg/L,19.3 mg/L,Cu²⁺ 101.5 mg/L,Ni²⁺ 101.5 mg/L.Through the study of the influencing factors and the analysis of the experimental data,the optimal parameters to reduce the pollutant concentration are determined,which will provide the reference for the process and data of the sewage treatment equipment with small footprint,high integration and convenient operation.For the treatment of high concentration organic matter,the UV / H2O2 was selected to combine its own Cu²⁺ in the wastewater,and the COD was degraded without additional catalyst.In the aspect of heavy metal treatment,Cr6+ was treated by reduction method or flocculation method,then use neutralization and precipitation treated Cu²⁺,Ni²⁺,Cr3+.The optimal parameter of UV/ H2O2/ Cu²⁺ is determined by studying the COD removal rate.The dosage of H2O2 is 80 mmol/L,photocatalytic time is 180 min and pH=3,the COD removal rate was 87.14% in these conditions.The best parameter of Cr6+ reduction: the Na2SO3 is 4.5 times the dosage of the mass concentration of Cr6+,pH=3,the reaction time exceed 35 min.In the neutralization precipitation experiments,mechanical agitation time is not less than 8 min?60 r/min?;when the pH value is at the range of 9.0 to 9.5,has the best effect on removal of Cr3+;then adjust pH between 10 and 11,the removal rates of Cu²⁺ and Ni²⁺ reach the best level.Under optimum conditions,the corresponding removal rates of total chromium,Cr6+,Cu²⁺,Ni²⁺ are 95.65%,96.86%,95.65%,72.46%.Treat the mixed wastewater by UV/ H2O2/ Cu²⁺,then by reduction/neutralization and precipitation,the effect of combined treatment on removal rates of total chromium,Cr6+,Cu²⁺,Ni²⁺ are 95.85%?97.82%?96.98%?72.98%?Study on removal of heavy metal by electric flocculation,the optimal parameters: current density 5A/dm2,electrode distance is 2cm,flocculation time is 25³0 min pH=8.Under optimum conditions,the removal rates of total chromium,Cr6+,Cu²⁺,Ni²⁺ are 97.85%,95.69%,and 78.25%.In conclusion,first,the organics in the wastewater has a certain degree of interference on heavy metal removal,secondly,comparison between the removal efficiency of electric flocculation and that of combined treatment,In terms of total chromiumandCr6+,combined treatment removal efficiency is better.In the areas of Cu²⁺and Ni²⁺,electro-flocculation treatment results are better.