多硫化钙原位注入对铬污染地下水的修复OA

A groundwater site contaminated by hexavalent chromium(Cr(Ⅵ))was selected as the research object.The optimal remediation molar ratio of calcium polysulfide to Cr(Ⅵ)was determined as 2∶1 through laboratory experiments,and the leaching amount of Cr(Ⅵ)from the soil column was 116.91 mg.Based on these findings,a pilot-scale field test of in-situ injection for remediating chromium-contaminated groundwater was conducted.A fan-shaped monitoring network centered on the injection well was employed in the field test.Key indicators of groundwater,including pH,dissolved oxygen(DO),oxidation-reduction potential(ORP),and Cr(Ⅵ)concentration,were monitored periodically.The results show that influenced by the injection,the variation trends of these indicators in the downstream monitoring wells are consistent with those in the injection well:a decrease in ORP and DO,an increase in pH,and a significant correlation between groundwater sulfide content and Cr(Ⅵ)concentration.Additionally,the injection of the chemical agent leads to a reduction in the hydraulic conductivity of the groundwater within the remediation area.Ultimately,a fan-shaped remediation zone with a radius of approximately 2 m is established.The research findings provide an important basis for the application of in situ groundwater remediation technology in similar contaminated sites.