Modification of treatment process for the complexed zinc-and nickel-containing wastewater in an electroplating park
[Introduction]The electroplating wastewater is difficult to treat because the metal ions in it are usually in form of stable complexes.The original process for treatment of complex wastewater in an electroplating park was precipitation by oxidation decomplexation at first stage and chelation at second stage.The concentrations of total nickel and total zinc in effluent couldn't stably meet the discharge standard.[Method]The first-stage wastewater treatment process was transformed into precipitation by denitrification decomplexation,while the second-stage chelation precipitation process remained the same.[Result]The concentrations of total nickel and total zinc in the effluent of the modified treatment process met the requirements of Table 3 in the Emission Standard of Pollutants for Electroplating(GB 21900-2008).The operation cost per ton of wastewater was reduced by about 30 RMB as compared with that of the original treatment process,saving 720000 RMB for the enterprise a year.[Conclusion]The modified process has good operation stability and high treatment efficiency,and good environmental and economic benefits.
electroplating wastewaterzincnickeldecomplexationchelation precipitationcost reduction and efficiency increase
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