Sequential anaerobic and aerobic bioaugmentation for commingled groundwater contamination of trichloroethene and 1,4-dioxane
Sequential anaerobic and aerobic bioaugmentation for commingled groundwater contamination of trichloroethene and 1,4-dioxane
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DOI：
10.1016/j.scitotenv.2021.145118
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发表时间：
2021-02-19
影响因子：
9.8
通讯作者：
Li, Mengyan
中科院分区：
文献类型：
--
作者：
Li, Fei;Deng, Daiyong;Li, Mengyan
氯化溶剂，特别是三氯乙烯（TCE）和环醚稳定剂，1，4-二氧六环（二氧六环），经常被发现混合在受污染的含水层中。在这里，我们开发了一个连续的厌氧和好氧处理策略，有效地减轻TCE和二氧杂环己烷的共污染，特别是当二氧杂环己烷存在于ppb水平相关的许多受影响的网站。经过一级厌氧处理的halorespiring财团SDC-9，TCE被有效地去除，虽然挥之不去的氯代代谢物，氯乙烯（VC）和顺式二氯乙烯（cDCE）。随后的有氧生物强化固氮菌属DD 4，共代谢的二氧六环降解剂，证明了DD 4降解二氧六环的能力，在初始浓度为20微克/升，低于0.4微克/升，其优势（类似于7%），在与丙烷饲养的缩影。更好的是，DD 4还可以串联转化VC和cDCE，尽管cDCE和VC在相对高的浓度下（例如，1 mg/L）对DD 4的丙烷同化和细胞生长有抑制作用。DD 4的突变显示2型甲苯单加氧酶和5型丙烷单加氧酶分别负责cDCE和VC的共氧化。总体而言，我们证明了将还原脱卤和好氧共氧化过程串联起来的处理系列的可行性，不仅可以有效地清除痕量水平的普遍的TCE和二恶烷共污染，而且还可以减少持久性产物（例如，cDCE和VC）时，完全还原脱卤低氯乙烯发生缓慢的领域。(c)2021爱思唯尔有限公司版权所有。
Chlorinated solvents, notably trichloroethene (TCE), and the cyclic ether stabilizer, 1,4-dioxane (dioxane), have been frequently detected commingling in contaminated aquifers. Here we developed a sequential anaerobic and aerobic treatment strategy effective to mitigate the co-contamination of TCE and dioxane, particularly when dioxane is present at ppb levels relevant to many impacted sites. After the primary anaerobic treatment by a halorespiring consortium SDC-9, TCE was effectively removed, though lingering less-chlorinated metabolites, vinyl chloride (VC) and cis-dichloroethene (cDCE). Subsequent aerobic bioaugmentation with Azoarcus sp. DD4, a cometabolic dioxane degrader, demonstrated the ability of DD4 to degrade dioxane at an initial concentration of 20 mu g/L to below 0.4 mu g/L and its dominance (similar to 7%) in microcosms fed with propane. Even better, DD4 can also transform VC and cDCE in tandem, though cDCE and VC at relatively high concentrations (e.g., 1 mg/L) posed inhibition to propane assimilation and cell growth of DD4. Mutagenesis of DD4 revealed group-2 toluene monooxygenase and group-5 propane monooxygenase are responsible for cDCE and VC co-oxidation, respectively. Overall, we demonstrated the feasibility of a treatment train combining reductive dehalogenation and aerobic co-oxidation processes in tandem to not only effectively clean up prevalent co-contamination of TCE and dioxane at trace levels but also mitigate persistent products (e.g., cDCE and VC) when complete reductive dehalogenation of less-chlorinated ethenes occurs slowly in the field. (c) 2021 Elsevier B.V. All rights reserved.