Dangi Mohan B, Urynowicz Michael A, Schultz Christopher L, Budhathoki Samir, Dangi Sadikshya R
Department of Geography and City & Regional Planning, California State University, Fresno, CA, 93740, USA.
Department of Civil & Architectural Engineering, University of Wyoming, Laramie, WY, 82071, USA.
Heliyon. 2021 Dec 23;7(12):e08665. doi: 10.1016/j.heliyon.2021.e08665. eCollection 2021 Dec.
chemical oxidation is an effective groundwater remediation approach for delivering oxidants to the subsurface environment where various contaminants of concern, natural organic matter, and other reduced species within the soil consume the oxidants. The addition of these oxidants alters microbial activity changing the physical and chemical structure of the soil. This paper studied the effects of chemical oxidation on microbial activity with and without toluene. Several oxidants were used as part of the study: sodium percarbonate, hydrogen peroxide, potassium permanganate, and sodium persulfate evaluated at low, medium, and high concentrations. A series of biometer experiments seeded with microbe and soil sample and aqueous toluene solution for each oxidant was monitored by CO production as a function of incubation days to evaluate the effects of oxidation on the microbial activity. Of the oxidants tested, permanganate oxidation resulted in the highest increase in microbial activity post oxidation based on CO production both with and without the addition of toluene. The other oxidants exhibited a direct correlation between oxidant concentration and the change in permanganate chemical oxidant demand of the soil. However, there was no correlation between oxidant concentration and microbial activity. Each of the oxidants was shown to increase CO yield except for sodium percarbonate, which had an adverse effect on microbial activity. It is likely that the increased microbial activity associated with permanganate oxidation was the result of chemical reactions between the oxidant and natural organic matter in the soil.
化学氧化是一种有效的地下水修复方法，可将氧化剂输送到地下环境中，在那里各种关注的污染物、天然有机物和土壤中的其他还原物质会消耗这些氧化剂。添加这些氧化剂会改变微生物活性，从而改变土壤的物理和化学结构。本文研究了化学氧化对有甲苯和无甲苯情况下微生物活性的影响。作为研究的一部分，使用了几种氧化剂：过碳酸钠、过氧化氢、高锰酸钾和过硫酸钠，并在低、中、高浓度下进行了评估。通过监测作为培养天数函数的一氧化碳产生量，对一系列接种了微生物、土壤样品和每种氧化剂的甲苯水溶液的生物计量实验进行了监测，以评估氧化对微生物活性的影响。在所测试的氧化剂中，基于一氧化碳产生量，无论是否添加甲苯，高锰酸钾氧化在氧化后导致微生物活性增加最多。其他氧化剂在氧化剂浓度与土壤的高锰酸盐化学氧化剂需求量变化之间呈现出直接相关性。然而，氧化剂浓度与微生物活性之间没有相关性。除过碳酸钠对微生物活性有不利影响外，每种氧化剂均显示出可提高一氧化碳产量。与高锰酸钾氧化相关的微生物活性增加可能是氧化剂与土壤中天然有机物之间化学反应的结果。
