零价铁/生物强化技术原位修复受氯代烯烃污染的地下水

Remediation of Groundwater Contaminated with Chlorinated Alkenes In-Situ by Zero Valent Iron Coupling with Bioaugmentation

随着我国工业化进程的加快,许多城市出现了大量的工业遗留污染场地,导致地下水受到污染,其中氯代烯烃是普遍存在的污染物之一。针对受氯代乙烯污染的地下水,采用零价铁和微生物强化技术进行原位修复。在受污染场地地下16.5m处注入零价铁生物强化药剂后,考察地下水中三氯乙烯(TCE)、二氯乙烯(DCE)和氯乙烯(VC)浓度的变化情况,并对地下水中的微生物群落进行高通量测序分析。注入药剂之后,TCE在7d时完全降解。60d时DCE和VC的浓度均已降至风险控制值以下,达到修复标准。微生物群落分析表明,经过修复后的地下水中,微生物群落的丰富度和多样性明显升高。在修复之前,假单胞菌属(Pseudomonas)等丰度占比高达91.6%,药剂注入后,Pseudomonas的丰度急剧下降,相应地,主要的TCE降解菌梭菌属(Clostridium)和厌氧发酵菌毛球菌属(Trichococcus)的丰度明显升高,注药后期修复系统以厌氧发酵过程为主,克里斯滕森菌属(Christensenellaceae R-7group)、互营单胞菌属(Syntrophomonas)逐渐成为优势菌。利用零价铁/生物强化技术可以高效去除地下水中的氯代烯烃类污染物,达到修复目标。通过修复后的微生物群落分析,可以间接地反映出地下水的修复程度。

With the acceleration of China's industrialization process,a large number of industrial pollution sites have emerged in many cities,resulting in groundwater pollution.Chloroolefin is one of the ubiquitous pollutants.Technology of zero valent iron coupling with bioaugmentation was employed for remediation of groundwater contaminated with chloroolefin in-situ.Zero-valent iron bio-enhancement agent was injected into the contaminated site at 16.5 meters underground,and fates of trichloroethylene(TCE),dichloroethylene(DCE)and vinyl chloride(VC)in the groundwater were investigated,and the groundwater samples were taken for analysis to microbial community through high-through sequencing.TCE was completely removed at the 7th day after the agent injection.At the 6th day,DCE and VC declined to under risk values and reached at standard of remediation.Analysis of microbiological communities showed that the richness and diversity of microbial communities increased significantly.Abundance of genus Pseudomonas was 91.6%,but the abundance decreased sharply after injection of the agent.Meanwhile,abundance of TCE degrading bacteria,Clostridium and Trichococcus,increased significantly.At later stage of remediation,genera Christensenaceae R-7group and Syntrophomonas gradually became the dominant bacteria,which correspond to anaerobic fermentation process.Groundwater contaminated with chloroolefin can be effectively remedied by technology of zero valent iron coupling with bioaugmentation,which reaches demand object.The remediation level of groundwater can be indirectly reflected through the analysis of microbial community.