Center of Health & Bioresources, Bioresources, AIT Austrian Institute of Technology GmbH, Konrad-Lorenz-Straße 24, 3430 Tulln a.d. Donau, Austria.
Institute of Soil Research, Department of Forest- and Soil Sciences, Institute of Soil Sciences, University of Natural Resources and Applied Life Sciences, Konrad-Lorenz-Straße 24, 3430 Tulln, Austria.
Sci Total Environ. 2020 Jun 20;722:137802. doi: 10.1016/j.scitotenv.2020.137802. Epub 2020 Mar 7.
The pollutant perchloroethene (PCE) can often be found at urban contaminated sites. Thus in-situ clean-up methods, like remediation using zero valent iron (ZVI) or bacterial dechlorination, are preferred. During the remediation with ZVI particles anaerobic corrosion occurs as an unwanted, particle consuming side reaction with water. However, in this reaction H is formed, which is usually scarce during anaerobic microbial dechlorination. Dehalococcoides needs H for cell growth using it as an electron donor to dechlorinate chlorinated hydrocarbons. Combining application of ZVI with bacterial dechlorination can turn ZVI in a H donor leading to a more controllable bacterial dechlorination, a smaller amount of ZVI suspension and decreased remediation costs. In this study nano- and micro scaled ZVI particles (nZVI, mZVI) were combined in microcosms with two dechlorinating bacterial cultures. The two cultures showed different dechlorination behaviors with ethene and cis-DCE as final products. Phospholipid fatty acids (PLFA) associated with Dehalococcoides (18:1w7, 18:1w7c, 10:Me16:0) and Geobacteriaceae (16,1w7c; 15:0; 16:0) have been found in both bacterial cultures, slight differences in their abundance could explain the different dechlorinating behaviors. The combination of both bacterial cultures with mZVI led to a stimulated dechlorination process leading to about two times higher k for PCE dechlorination (0.01-0.05 h). In the otherwise cis-DCE accumulating culture complete dechlorination to ethene was achieved. While addition of nZVI inhibited both cultures. Combined with nZVI the completely dechlorinating culture produced lower amounts of dechlorinated products (3.2 μmol) as compared to the single biotic treatment (5.1 μmol). Combining the incompletely dechlorinating culture with nZVI significantly reduced the k (single: 8 × 10 ± 3 × 10 h; combination: 5 × 10 ± 2 × 10 h). H produced by nZVI and mZVI was utilized by both bacterial cultures. The particle size, resulting specific surface areas, agglomeration tendencies and reactivity appears to be crucial for the effect on microbial cells.
污染物全氯乙烯（PCE）通常存在于城市污染场地中。因此，原位修复方法，如使用零价铁（ZVI）或细菌脱氯进行修复，是首选的方法。在使用 ZVI 颗粒进行修复时，水的厌氧腐蚀会作为一种不需要的、消耗颗粒的副反应发生。然而，在这个反应中会形成 H，而在厌氧微生物脱氯过程中，H 通常是稀缺的。Dehalococcoides 需要 H 作为电子供体来脱氯氯化烃，从而进行细胞生长。将 ZVI 的应用与细菌脱氯结合起来，可以使 ZVI 成为 H 的供体，从而实现更可控的细菌脱氯，减少 ZVI 悬浮液的用量，并降低修复成本。在这项研究中，纳米和微尺度的 ZVI 颗粒（nZVI、mZVI）与两种脱氯细菌培养物一起在微宇宙中进行了组合。这两种培养物以乙烯和顺式-1,2-二氯乙烯作为最终产物表现出不同的脱氯行为。与 Dehalococcoides（18:1w7、18:1w7c、10:Me16:0）和 Geobacteriaceae（16,1w7c；15:0；16:0）相关的磷脂脂肪酸（PLFA）已在两种细菌培养物中被发现，它们丰度的细微差异可以解释不同的脱氯行为。将这两种细菌培养物与 mZVI 结合起来，会刺激脱氯过程，使 PCE 脱氯的 k 值提高约两倍（0.01-0.05 h）。在否则会积累顺式-1,2-二氯乙烯的培养物中，完全脱氯到乙烯得以实现。而添加 nZVI 则抑制了这两种培养物。与 nZVI 结合使用时，完全脱氯的培养物产生的脱氯产物（3.2 μmol）比单一生物处理（5.1 μmol）少。将不完全脱氯的培养物与 nZVI 结合使用，显著降低了 k 值（单一：8×10±3×10 h；组合：5×10±2×10 h）。nZVI 和 mZVI 产生的 H 被两种细菌培养物利用。颗粒尺寸、比表面积、团聚倾向和反应性似乎对微生物细胞的影响至关重要。
