Hochschule Wismar - University of Applied Sciences, Technology, Business, and Design, Faculty of Engineering Science, Department of Mechanical, Process and Environmental Engineering, Philipp-Müller-Str. 14, 23966, Wismar, Germany; Indian Institute of Technology Delhi, Department of Civil Engineering, Hauz Khas, New Delhi, 110016, India.
Hochschule Wismar - University of Applied Sciences, Technology, Business, and Design, Faculty of Engineering Science, Department of Mechanical, Process and Environmental Engineering, Philipp-Müller-Str. 14, 23966, Wismar, Germany.
J Environ Manage. 2024 Sep;368:121945. doi: 10.1016/j.jenvman.2024.121945. Epub 2024 Aug 14.
Zero-valent iron (ZVI) applied to the remediation of contaminated groundwater (GW) in situ, especially using engineered permeable reactive barriers (PRBs), has been proven to be an effective reactive material. However, many of ZVI brands do not represent tailored reagents specifically regarding destroying pollutants in GW. Thus, their reactivity towards certain contaminants in GW may vary significantly in a wide range even with different production batches of the same ZVI brand. This issue has rarely been known and consequently not addressed to a higher extend so far. Therefore, this study implemented extensive, long-term column experiments followed by short-term batch experiments for chlorinated volatile organic compounds (cVOCs) degradation for developing a semi-empirical test methodology to thoroughly resolve this pivotal issue by achieving an improved quality assurance guidance regarding proper field-scale emplacement of different ZVI brands and their production batches. The results showed that during column experiments perchloroethylene (PCE) led to a significant degradation up to a certain period but sulfate-reducing microorganisms enhanced the dehalogenation and led approximately to 100 % PCE removal. However, the efficacy varied for different ZVI brands, i.e., Gotthart Maier (GM) and Sponge Iron (Responge®). Furthermore, it could be shown that it might even vary among different production batches of the same ZVI brand. It was also observed that evolution of sulfate-reducing microorganisms may improve the efficacy of PCE degradation vastly that occur at different intensities with different ZVI brands and their respective production batches over time. Further, comparing comprehensive long-term column (k = 0.0488 1/h) and short-term batch experiments (k = 0.07794 1/h) as well as refined kinetic analyses (k = 0.0424 1/h) clearly prove that an appropriate guidance protocol for successful full-scale in situ remediation is required for properly select the right ZVI brand and production batch before it is loaded to a PRB in the field.
零价铁（ZVI）应用于原位修复受污染地下水（GW），特别是使用工程渗透性反应屏障（PRB），已被证明是一种有效的反应材料。然而，许多 ZVI 品牌并不代表针对 GW 中污染物的定制试剂。因此，即使是同一 ZVI 品牌的不同生产批次，其对 GW 中某些污染物的反应性也可能在很大范围内有很大差异。到目前为止，这个问题很少被人们所知，也没有得到进一步解决。因此，本研究通过广泛的长期柱实验和短期批量实验，对氯代挥发性有机化合物（cVOCs）的降解进行了研究，开发了一种半经验测试方法，通过实现对不同 ZVI 品牌及其生产批次在现场规模合理安置的改进质量保证指导，彻底解决了这个关键问题。结果表明，在柱实验中，全氯乙烯（PCE）在一定时期内导致了显著的降解，但硫酸盐还原微生物增强了脱卤作用，导致 PCE 几乎完全去除。然而，不同 ZVI 品牌的效果不同，即 Gotthart Maier（GM）和 Sponge Iron（Responge®）。此外，还可以看出，即使是同一 ZVI 品牌的不同生产批次，效果也可能不同。还观察到，硫酸盐还原微生物的演化可能会大大提高 PCE 降解的效果，这种效果会随着时间的推移，在不同的 ZVI 品牌及其各自的生产批次中以不同的强度发生。此外，通过比较全面的长期柱（k = 0.0488 1/h）和短期批量实验（k = 0.07794 1/h）以及细化的动力学分析（k = 0.0424 1/h），清楚地证明了在将 ZVI 品牌及其生产批次加载到 PRB 之前，需要有一个适当的指导协议，以成功地进行现场原位修复。
