微生物修复返溶铬污染场地的研究进展

Advances in microbial remediation of the re-dissolved chromium contaminated sites

目前,我国历史遗留铬渣堆场多数采用湿法解毒工艺进行处理,但大量化学药剂的添加不仅增加了成本,引入了污染物,而且随时间的延长铬渣中的Cr(Ⅵ)源源不断的返溶,场地出现返黄现象,形成二次污染。为了持久稳定的修复铬渣,研究人员提出用微生物修复技术处理湿法解毒后铬渣中Cr(Ⅵ)的返溶。文中综述了国内外微生物修复铬渣污染场地的研究进展,首先简述了铬渣的危害、处理现状及传统的铬污染修复技术,并以湿法解毒铬污染为例,重点揭示了处理后铬渣中Cr(Ⅵ)的返溶机理,由此可知湿法解毒后的二次污染不可避免。随后详述了微生物修复Cr(Ⅵ)过程中生物还原、生物吸附和生物矿化三大作用机理,并阐述了铬污染场地修复过程中微生物物种的响应及群落结构的演替,最后,总结了微生物修复铬渣的研究进展并展望了未来的研究方向。

Wet detoxification has traditionally been seen as the most promising technology for treating chromium-contaminated sites.However,the addition of chemicals in the wet detoxification process not only increases the cost but also introduces extra pollutants.Moreover,the chromium-containing slag may be re-dissolved in the form of Cr(VI),and the increased concentration of Cr(VI)results in a serious“returning to yellow”phenomenon in the chromium-contaminated sites,causing undesirable secondary pollution.Microbial remediation is a promising technology to address the re-dissolution of chromium-containing slag after wet detoxification,and this article reviews the advances in this area.Firstly,the toxicity,current situation and conventional technologies for treating the chromium-containing slag were briefly summarized.The mechanisms of the inevitable re-dissolution of chromium-containing slag after wet detoxification were summarized.Three main mechanisms,namely bioreduction,biosorption and biomineralization,which are involved in the environmental-friendly and efficient microbial remediation technology,were reviewed.The variation of microbial species and the succession of microbial community during the bioremediation of chromium-contaminated sites were discussed.Finally,future research directions were prospected with the aim to develop long-term,stable and sustainable technologies for remediating the chromium-contaminated sites.