青海省海北化工厂Cr^(6+)污染调查评价与治理

ASSESSMENT AND TREATMENT OF Cr^(6+) POLLUTION IN THE HAIBEI CHEMICAL PLANT IN QINGHAI PROVINCE

海北化工厂已停产15年之久,但Cr6+污染依旧十分严重.调查得知,海北化工厂原生产废液排放及堆存废渣经降水淋滤作用下渗,是造成该区包气带和地下水Cr6+污染的主要原因.采用地下水质量法和污染指数法评价分析该区地下水Cr6+污染范围和污染影响程度.评价结果显示:Cr6+重度污染区面积0.75 km2,厂区包气带Cr6+平均含量67.67×10-6,平均超标指数1691.75,地下水中Cr6+浓度超过Ⅴ类水标准.在分析厂区周边水文地质条件的基础上,提出清除场地废渣废料并置换被污染的包气带、采用抽水法治理被污染的地下水的综合方案.

The Haibei Chemical Plant has stopped production for 15 years,but the Cr6＋ pollution of the site is still serious.Investigation shows that the original pollutant source is the production waste and the remaining liquid waste,which leached into the soil with rainfall and polluted the soil and the groundwater.The quality of soil and groundwater is evaluated with groundwater quality standard and pollution index method.The result reveals that an area of 0.75 km2 has been seriously polluted.The average Cr6＋ content in the unsaturated zone is detected to be 67.67×10-6,which exceeds the standard of Grade V water.By analyzing the hydrogeological conditions and the assessment data,it is suggested that soil replacement and pumping method should be adopted to clean up the Cr pollutant from soil and groundwater in the area.