铬污染土壤的微生物修复工艺及中试

Bioremediation of Cr( Ⅵ) contaminated soil and pilot study

本研究利用土柱试验研究了铬污染土壤微生物修复的各工艺参数,结果表明:土壤粒径、喷淋强度、以及修复工艺对铬污染土壤的修复效果有很大的影响.最佳的工艺参数为:土壤粒径1～2 cm、喷淋强度在29.6～59.2 mL·min-1、工艺制度Ⅱ(先用自来水淋洗1 d,接着用菌液循环喷淋).在土柱试验的基础上开展了25吨/批的中试试验,铬污染土壤经过7～10 d的处理,土壤中Cr(Ⅵ)浸出毒性浓度由53.8 mg·L-1降低至0.4 mg·L-1,达到《铬渣污染治理环境技术规范》(HJ/T301～2007)中铬渣用作路基材料和混凝土骨料的标准限值,证明铬污染土壤微生物修复工业化具有可行性,为铬污染土壤工程化修复提供了技术支撑.

This research investigated the crucial parameters in the bioremediation of Cr（Ⅵ）- contaminated soil. The results indicated soil particle size, spray intensity, Cr（Ⅵ） concentration and process systems obviously influenced the bioremediation efficiency of Cr（Ⅵ）. The optimal parameters were 1—2 cm of soil particle size, 29.6—59.2 mL·min^-1 of spray intensity, leaching 1d with tap-water followed by culture medium inoculated with microorganism. A pilot experiment （25t/batch） showed Cr（Ⅵ） leaching concentration declined from an insital concentration of 53.8 mg·L-1 to 0.41 mg·L-1 after 7—10 days remediation, which was lower than the Cr（Ⅵ） limit of chromium-containing slag used as roadbed material and concrete according to the Environmental Protection Technical Specifications for Pollution Treatment of the Chromium Residue. The results provide an innovative way for the remediation of chromium contaminated soils in a large scale engineering.