电镀废水处理后重新出现六价铬问题的研究

摘要

采用铁屑内电解法处理含铬废水,采用次氯酸钠氧化法处理含氰废水,将两种处理好的废水同时排入中间池后,水样中重新出现六价铬.研究表明:含氰废水中过量的次氯酸钠将废水中的三价铬氧化为六价铬.工程实践中采取在含氰废水中加入适量亚硫酸氢钠去除余氯的工艺,获得了稳定的处理效果.%Iron chip inner electrolysis process was used to treat wastewater containing chromium, and sodium hypochlorite oxidization method was used for treating wastewater containing cyanide. When these two kinds of treated wastewater were discharged into the medium tank at the same time, hexavalent chromium reappeared in the water samples. The research resulted show that the trivalent chromium was oxidized to hexavalent chromium by excessive sodium hypochlorite in wastewater containing cyanide. In engineering practice, an appropriate amount of sodium bisulfite was added to remove residual chlonne in wastewater containing cyanide, obtaining a stable treatment effect.