Lab-Scale Biodegradation Study of BTEX under the Unsaturated Condition and Its Effect on Soil Matric Potential
Lab-Scale Biodegradation Study of BTEX under the Unsaturated Condition and Its Effect on Soil Matric Potential
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DOI：
10.1080/15320383.2018.1556597
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发表时间：
2019-02
期刊：
影响因子：
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通讯作者：
K. S;Sangeetha Cj;S. T
中科院分区：
文献类型：
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作者：
K. S;Sangeetha Cj;S. T
摘要 苯、甲苯、乙苯和二甲苯统称为苯系物，是挥发性环境污染物。本研究调查了批量和连续土柱实验中苯系物的微生物降解及其对土壤基质势的影响。使用从石油污染土壤中分离出的耐苯系物培养物，对不同初始浓度的苯系物进行了批量降解实验。在批量研究中，单一底物的降解模式表明，在初始底物浓度为 100 mg L−1 时，二甲苯的降解速度比其他化合物快得多，其次是乙苯、甲苯和苯，最高 μmax = 0.140 h−1。在入口苯系物浓度约为2000 mg·L−1的土柱中，在厌氧条件下的不饱和流下进行连续降解实验。研究了苯系物随时间的降解模式，并在实验结束时确定了沿柱长度不同部分的土壤基质势。在连续降解研究中，苯系物化合物以不同的降解模式降解，并且观察到土壤基质势随着施加吸头的柱中从上到下深度的增加而增加。结果发现，柱生物降解有助于减少 69.5% 的苯系物，细菌生长沿柱高度平均使土壤基质势增加约 34%。因此，本研究证明，在模拟非饱和土壤中苯系物的归宿和迁移时考虑土壤基质势具有重要意义。
ABSTRACT Benzene, toluene, ethylbenzene, and xylene are collectively known as BTEX which contributes to volatile environmental contaminants. This present study investigates the microbial degradation of BTEX in batch and continuous soil column experiments and its effects on soil matric potential. Batch degradation experiments were performed with different initial concentrations of BTEX using the BTEX tolerant culture isolated from petroleum-contaminated soil. In batch study, the degradation pattern for single substrate showed that xylene was degraded much faster than other compounds followed by ethylbenzene, toluene, and benzene with the highest μmax = 0.140 h−1 during initial substrate concentration of 100 mg L−1. Continuous degradation experiments were performed in a soil column with an inlet concentration of BTEX of about 2000 mg L−1 under unsaturated flow in anaerobic condition. BTEX degradation pattern was studied with time and the matric potential of the soil at different parts along the length of the column were determined at the end of the experiment. In continuous degradation study, BTEX compounds were degraded with different degradation pattern and an increase in soil matric potential was observed with an increase in depth from top to bottom in the column with applied suction head. It was found that column biodegradation contributed to 69.5% of BTEX reduction and the bacterial growth increased the soil matric potential of about 34% on an average along the column height. Therefore, this study proves that it is significant to consider soil matric potential in modeling fate and transport of BTEX in unsaturated soils.