化学还原法处理电镀含铬废水的工程应用

Discussion on Treatment of Electroplating Wastewater Containing Chromium (Ⅵ) by Chemical Reduction

用亚硫酸氢钠作还原剂处理含铬电镀废水时,不调节废水pH值会出现暂时定性检测不含六价铬的假象,过一段时间废水中又会出现六价铬,导致排水不达标。针对这一现象进行实验和工程实践,结果表明,不调节pH值增加亚硫酸氢钠的投加量和不增加亚硫酸氢钠投加量而pH值调节到3～4都能使处理后水质稳定,达到排放标准(GB21900—2008)中六价铬质量浓度小于0.2 mg/L的要求。

When the reducing agent of sodium bisulfite is used in treating electroplating wastewater containing hexavalent chromium and pH value of wastewater is not adjusted, there was not hexavalent chromium in qualitative detection, but hexavalent chromium again appears in wastewater over time and leads substandard drainage. Experimental results and engineering practice shows： It can obtain the steady quality of treated water and meet emission standard （GB21900- 2008） that pH value is not adjusted to increase sodium bisulfite dosage and pH value is adjusted to 3 to 4 without increasing sodium bisulfite dosage. The content of hexavalent chromium is less than 0.2 mg/L.