磷酸盐稳定化修复锌污染土壤小试和工程效果评估

采用磷矿粉和某商业药剂为主要稳定化修复材料，针对某典型锌污染场地（包括锌污染土壤和工业废渣）开展实验室小试、稳定化修复工程和长期跟踪稳定化效果评估。结果表明，采用磷矿粉+熟石灰组合对锌污染土壤和建筑废渣具有长期稳定并大幅降低污染介质中锌浸出浓度的效果，实验室小试时投加比为2%时，锌的浸出可完全满足场地修复目标值25 mg·L-1的浓度限值；在现场施工时，为保守起见，设定稳定化药剂投加比例4%，在稳定化过程中，pH变化趋势为逐渐升高到11左右，然后降低稳定至7.0左右，废渣和污染土壤中锌浸出分别为0.2 mg·L-1、0.05 mg·L-1以下；稳定化修复后450 d，再次采样测定锌的浸出和pH，结果分别为低于0.2~2.0 mg·L-1和7.3左右，完全达到预期长期稳定化效果。实验室小试和稳定化工程结果可为后续锌污染场地治理修复提供技术参考和借鉴。

Effects evaluation of phosphate stabilized zinc contaminated soil in laboratory test and field remediation construction

A typical zinc contaminated site including zinc contaminated soil and industrial waste residue was remediated adopting phosphate ore and a certain kind of commercial reactant as mainly stabilization materials. Meanwhile, laboratory bench-scale experiment, stabilization remediation construction and long-term performance appraisal of stabilization are evaluated. Based on the results, the combination of phosphate ore and slaked lime has positively long-term effect on the stability of remediated contaminated soil and industrial waste residue, reducing the leaching concentration of zinc in pollutant medium. When the dosing ratio in laboratory bench-scale experiment was 2%, the leaching zinc concentration could meet the remediation target 25 mg·L-1. During the on-site construction, to be prudent, the stabilization reactant dosing ratio was set as 4%. During the stabilizing processes, pH of contaminated soils was gradually increased to around 11, and then returned to around 7 after it was stable. The results show that the zinc leaching concentration of waste residue and contaminated soil was 0.2 mg·L-1 and 0.05 mg·L-1 respectively. After 450 days of the stabilized remediation, the zinc leaching concentration and pH of resampling results were from 0.2 mg·L-1 to 2.0 mg·L-1 and around 7.3, respectively. It is perfectly satisfied with the predicted long-term stabilization result. The laboratory bench-scale experiment and stabilization remediation construction could be referential to subsequent remediation of zinc contaminated sites.