Engineering application of heap elution process to deal with cyanide pollution oil

The heap elution process was used to treat cyanide pollution soil, and industry experiment was finished. Results showed that after 45 days of washing, cyanide content in the soil can be reduced from 114.30 mg/kg to 5.57 mg/kg, reaching the risk screening guideline value of less than 9.86 mg/kg. The cyanide leaching toxicity of the soil was 0.017 mg/L, reached Class Ⅳ of Groundwater Environment Quality Standard (GB 14848-93). At the same time, alkaline water washing can remove part of organic matter in the soil. The alkaline chlorine oxidation method was adopted to detoxicate the wastewater. Finally, the concentration of cyanide in wastewater was 0.05 mg/L, COD was 30.52 mg/L, chlorine concentration was 0.06 mg/L, and the concentration of heavy metals was low, all meeting the emission limit in Comprehensive Wastewater Discharge Standard (GB 8978-1996). Eventually the wastewater can be discharged directly.