Siggins Alma, Thorn Camilla, Healy Mark G, Abram Florence
School of Natural Sciences, National University of Ireland, Galway, Ireland; Civil Engineering, National University of Ireland, Galway, Ireland; Ryan Institute, National University of Ireland, Galway, Ireland.
School of Natural Sciences, National University of Ireland, Galway, Ireland; Ryan Institute, National University of Ireland, Galway, Ireland.
J Hazard Mater. 2021 Feb 5;403:123676. doi: 10.1016/j.jhazmat.2020.123676. Epub 2020 Aug 14.
Trichloroethylene (TCE) is a human carcinogen that is commonly found in landfill leachate. Contaminated leachate plumes may be intercepted prior to reaching groundwater and treated in situ using permeable reactive barriers (PRB). This study used a packed column system containing herbal pomace and spruce biochar, previously shown to have TCE adsorptive capabilities. Influent containing raw or autoclaved landfill leachate was used to investigate the potential for environmental micro-organisms to establish a TCE-dechlorinating biofilm on the biochar, in order to prolong the operational life span of the system. TCE removal ≥ 99.7 % was observed by both biochars. No dichloroethylene (DCE) isomers were present in the column effluents, but cis-1,2 DCE was adsorbed to the biochar treating raw landfill leachate, indicating that dechlorination was occurring biologically in these columns. Known microbial species that are individually capable of complete dechlorination of TCE to ethene were not detected by 16S rRNA gene sequencing, but several species capable of partial TCE dechlorination (Desulfitobacterium spp., Sulfurospirillium spp. and Desulfuromonas spp) were present in the biofilms of the columns treating raw landfill leachate. These data demonstrate that biochar from waste material may be capable of supporting a dechlorinating biofilm to promote bioremediation of TCE.
三氯乙烯（TCE）是一种常见于垃圾渗滤液中的人类致癌物。受污染的渗滤液羽流在到达地下水之前可能会被拦截，并使用渗透性反应屏障（PRB）进行原位处理。本研究使用了一个装有草药渣和云杉木生物炭的填充柱系统，先前的研究表明该系统具有TCE吸附能力。使用含有未经处理或经高压灭菌的垃圾渗滤液的进水，来研究环境微生物在生物炭上形成TCE脱氯生物膜的可能性，以延长系统的使用寿命。两种生物炭对TCE的去除率均≥99.7%。柱流出物中不存在二氯乙烯（DCE）异构体，但顺式-1,2-DCE被吸附在处理未经处理的垃圾渗滤液的生物炭上，这表明这些柱中正在发生生物脱氯。通过16S rRNA基因测序未检测到能够将TCE完全脱氯为乙烯的已知微生物物种，但在处理未经处理的垃圾渗滤液的柱生物膜中存在几种能够部分脱氯TCE的物种（脱硫脱硫弧菌属、硫还原螺旋菌属和脱硫单胞菌属）。这些数据表明，来自废料的生物炭可能能够支持脱氯生物膜，以促进TCE的生物修复。
