化工厂场地酸化土壤工程化中和修复案例研究

Case Study on Engineering Remediation of Acidified Site Soil in a Chemical Plant by a Neutralizing Reaction

对江苏某化工厂酸化地块进行了氧化钙中和修复工程研究。Ⅰ、Ⅱ、Ⅲ号地块剖面混合土样pH值分别为3.56、4.68和4.74,土壤修复目标定在pH值为6~8基本近中性。通过室内试验确定Ⅰ、Ⅱ、Ⅲ号地块土壤生石灰掺混比例为0.5%、0.3%和0.3%;现场中试后Ⅰ、Ⅱ、Ⅲ号地块石灰掺混比例调整为0.7%、0.35%和0.3%;中试结果用于场地机械搅拌工程修复,修复过程中定期随机采样对中和效果进行连续监测。监测结果基本达标后请第三方对修复效果进行评估,最后土壤回填压实。修复结果表明借助于科学的石灰添加量和工程机械混合措施,能快速有效地修复酸化地块土壤。

Engineering remediation with CaO for an acidified site in a chemical plant in Jiangsu Province was carried out in this study.The pH of composite soil samples taken from soil profiles in Ⅰ,Ⅱ and Ⅲ acidified zones were 3.56,4.68 and 4.74 respectively.The soil pH remediation objective was set at 6～8 near neutral range.Determined by laboratory quick test,the theoretical lime-soil mixture ratio was 0.5%,0.3% and 0.3% for Ⅰ,Ⅱ,Ⅲ acidified zones respectively.After pilot scale test,the final adjusted ＂lime-soil＂ mixture ratio was 0.7%,0.35% and 0.3% and the ratio was used for the soil mechanical agitation with continuous soil pH monitoring until the results reaching the remediation goal.Then a third party with relevant certification was invited to evaluate the remediation effect.The remediation result showed that combining reasonable lime-soil mixture ratio and mechanical measures could quickly and effectively remediate the acidified soil.