LAYOUT OPTIMIZATION OF PUMPING AND INJECTION WELLS FOR LEACHING RESTORATION IN ENCLOSED CONTAMINATED SITES

In order to prevent the expansion of the contaminated sites and pollution of groundwater, engineering measures can be taken to enclose the contaminated site around and below. The contaminated soil within the enclosure can be repaired by leaching. Taking the contaminated site left by Qingdao Steam Turbine Co., Ltd. as an example, visual MODFLOW was used to simulate the layout and hydraulic conditions of the optimized water injection and pumping wells, for remediation of contaminated leaching in the enclosed site. Through the technical and economic comparison of 9 groups of injection and pumping well combinations, the optimal spacing of injection and pumping wells was 27 m, the optimal water injection and pumping capacity was 200~300 m³, and the arrangement mode was one injection-five pumping. The economic comparison with the ectopic disposal scheme showed that 7000 m³ contaminated soil was cost limit for the two schemes: the project with earthwork of 7000 m³ above should adopt leaching repair scheme, otherwise, the ectopic treatment method should be considered.