Department of Civil Engineering, IIT (ISM) Dhanbad, Dhanbad, Jharkhand, 826004, India.
Department of Environmental Science and Engineering, IIT (ISM) Dhanbad, Dhanbad, Jharkhand, 826004, India.
Environ Sci Pollut Res Int. 2023 Aug;30(37):88022-88035. doi: 10.1007/s11356-023-28506-9. Epub 2023 Jul 12.
Biostimulation of aquifers contaminated with gasoline spills is vigorously affected by the biogeochemical environment existing there. In this study, biostimulation of benzene is simulated using a 2D coupled multispecies biogeochemical reactive transport (MBRT) model. The model is implemented at an oil spill site near a hypothetical aquifer containing natural reductants. Multiple electron acceptors are introduced to promote faster biodegradation rate. However, after reaction with natural reductants, it reduces the number of available electron acceptors, acidifies the subsurface environment, and inhibits bacterial growth. These mechanisms are assessed using seven coupled MBRT models sequentially. The finding of the present analysis reveals that biostimulation has caused a substantial drop in concentration of benzene and is efficient in reducing its penetration depth. The results also shows that the intervention of natural reductants in the biostimulation process is slightly diminished by pH adjustment of aquifers. When the pH level in aquifer changes from acidic pH 4 to neutral pH 7, it is observed that the biostimulation rate of benzene as well as microbial activity increases. Electron acceptors consumption is more at neutral pH. Overall, it can be inferred from zeroth-order spatial moment and sensitivity analyses that retardation factor, inhibition constant, pH, and dispersivity in vertical direction significantly affect benzene biostimulation in aquifers.
受污染含水层中的生物刺激强烈受到那里存在的生物地球化学环境的影响。在这项研究中，使用二维耦合多物种生物地球化学反应传输（MBRT）模型模拟了苯的生物刺激。该模型在一个假设的含水层附近的溢油现场实施，该含水层含有天然还原剂。引入多种电子受体以促进更快的生物降解速率。然而，与天然还原剂反应后，它会减少可用电子受体的数量，使地下环境酸化，并抑制细菌生长。使用七个顺序耦合的 MBRT 模型评估这些机制。本分析的结果表明，生物刺激导致苯的浓度大幅下降，并有效地降低了其穿透深度。结果还表明，通过调节含水层的 pH 值，天然还原剂在生物刺激过程中的干预作用会略有减弱。当含水层的 pH 值从酸性 pH4 变为中性 pH7 时，观察到苯的生物刺激速率以及微生物活性增加。中性 pH 值下电子受体的消耗更多。总体而言，可以从零阶空间矩和敏感性分析推断，阻滞因子、抑制常数、pH 值和垂直方向的弥散度对含水层中的苯生物刺激有显著影响。
