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首页> 外文学位 >Feasibility study for combined in situ thermal desorption and biodegradation of PAH-contaminated soils.
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Feasibility study for combined in situ thermal desorption and biodegradation of PAH-contaminated soils.

机译：原位热脱附和PAH污染土壤生物降解联合研究的可行性。

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The overall objective of this dissertation is to test the feasibility of combining thermophilic bioremediation with thermal desorption for the treatment of PAH-contaminated soil. A bacterium was isolated from a lampblack soil sample taken from a former manufactured gas plant (MGP) facility. Analysis on 16S rRNA revealed that the bacterium was closely related to Microbacterium laevaniformans. In an aqueous microcosm our bacterium, designated M. laevaniformans LA, was found to be capable of removing naphthalene concentrations from near solubility to a non-detectable level under denitrifying and aerobic conditions. The rate of naphthalene degradation was 0.63 μfor denitrifying conditions compared to 14.87 μg/mL/day under aerobic conditions. PAH's larger than naphthalene were not observably degraded by the bacterium. Microcosms were then designed to observe the potential for chemical (cosolvents and surfactants) enhancement of PAH bioremediation. Results in this aspect of the study were negative.; The second part of this research was intended to test the feasibility of combining in situ thermal desorption with biodegradation as a PAH remediation technology, using naphthalene as a model PAH. Results from batch soil columns operated under uniform mesophilic temperature (34.2°C) demonstrated that M. laevaniformans LA was capable of reducing naphthalene concentrations to well below those observed in control columns (abiotic). Aqueous naphthalene concentrations remained sufficiently elevated in the soil column to suggest that its utilization was limited by electron acceptor availability. Batch soil columns subjected to a temperature gradient exhibited similar naphthalene removal (to the uniformly heated columns) for the mesophilic regions of the column. M. laevaniformans LA was unable to sustain observable naphthalene utilization in a flowing column test. It appeared that the microorganism was incapable of maintaining a growth rate sufficient to avoid being washed out. Batch soil columns packed with real MGP soil and subjected to a temperature gradient exhibited a behavior similar to the for the model systems, confirming the feasibility of the process for real (as opposed to spiked) contaminant conditions.; Overall, the results here suggest that thermal desorption is feasible as a tool to improve PAH biodegradation due to PAR mobilization with heat.
机译：本文的总体目标是检验将嗜热生物修复与热解吸相结合用于处理PAH污染土壤的可行性。从以前的天然气工厂（MGP）设施中抽出的油烟土样品中分离出细菌。 16S rRNA分析表明该细菌与 laevaaniformans 密切相关。在一个水的微观世界中，我们的细菌称为 laevaniformans LA，能够在反硝化和好氧条件下将萘浓度从接近溶解度去除到无法检测的水平。脱氮条件下萘的降解速率为0.63μm，而好氧条件下为14.87μg/ mL / day。该细菌不能降解大于萘的PAH。然后设计缩影，以观察化学（助溶剂和表面活性剂）增强PAH生物修复的潜力。该研究结果为阴性。本研究的第二部分旨在测试以萘为模型的PAH结合原位热解吸和生物降解作为PAH修复技术的可行性。在均匀的中温温度（34.2°C）下操作的分批土壤柱的结果表明，。 laevaniformans LA能够将萘浓度降低到远低于对照柱（非生物）中观察到的浓度。在土壤柱中萘水溶液的浓度仍然足够高，表明其利用率受到电子受体可用性的限制。经受温度梯度作用的分批土壤色谱柱对中温区的脱除萘（与均匀加热的色谱柱相似）。 <斜体> M。 laevaniformans LA在流动柱测试中无法维持可观察到的萘利用率。看来微生物不能保持足以避免被洗掉的生长速率。装满实际MGP土壤并经受温度梯度的分批土壤柱表现出与模型系统相似的行为，证实了该方法在真实（与加标）污染条件下的可行性。总的来说，这里的结果表明，热解吸作为改善PAH生物降解的一种工具是可行的，这是由于PAR通过加热而动员的。

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