Bioavailability and Biodegradation of Organic Contaminants In Heterogenous Subsurface Environments

9523870米勒生物利用度和有机污染物在非均质地下环境中的生物降解。就地生物修复是污染土壤和地下水环境净化技术中最有前途和最具成本效益的技术之一。原位生物修复是利用微生物恢复受污染的环境，而不必挖掘或以其他方式干扰受污染的场地。许多自然环境中都含有能够降解(破坏)污染物的微生物群落。成功实施原位生物修复面临着两个严重的问题。这些是在自然环境中发现的物理和化学不均一性，以及污染物在固体表面(粘土或沙粒)吸附(粘连)所导致的污染物可获得性降低。该项目的目标是使用综合的生物和物理/化学方法来研究控制自然(非均质)地下环境中生物修复的因素。这项建议概述了一种独特的方法，以了解异质性对污染物有效性的影响，以及如何克服可用性限制以提高生物修复的规模和速度。这种方法将最先进的中等规模流动和传输实验与先进的技术相结合，以确定污染物降解微生物的数量和活性(发光微生物的光纤检测)。这一方法将能够同时检测污染物的传输和微生物活动，从而能够调查污染物的空间异质性与微生物介导的销毁的可获得性之间的关系。此外，该方法将用于评估控制微生物在非均质环境中运输的物理和生物参数，并将微生物加强运输的机制与它们加强难以接触的有机污染物的降解的潜力联系起来。该办法还将用于评估加强就地生物修复的战略，例如，应用表面活性剂(洗涤剂)可增加可吸附污染物的可用性。研究结果将提高我们对这些问题的认识，并将在预测污染物的运移和归宿、评估地下水污染潜力以及操纵地下系统以提高生物修复技术的有效性方面取得重大进展。

9523870 Miller Bioavailability and Biodegradation of Organic Contaminants in Heterogeneous Subsurface Environments. One of the most promising and cost-effective environmental cleanup technologies for contaminated soil and groundwater is in situ bioremediation. In situ bioremediation is the use of microorganisms to restore a contaminated environment without having to excavate or otherwise disturb the contaminated site. Many natural environments contain microbial communities capable of degrading (destroying) pollutants. There are two serious problems facing successful implementation of in situ bioremediation. These are the physical and chemical heterogeneities found in natural environments, and the reduced availability of contaminants that results from the sorption (sticking) of contaminants to solid surfaces (clay or sand particles). The goal of this project is to use an integrated biological and physical/chemical approach to investigate the factors controlling bioremediation in natural (heterogeneous) subsurface environments. This proposal outlines a unique approach to understanding the effect of heterogeneity on contaminant availability, and how availability constraints can be overcome to enhance the magnitude and rate of bioremediation. This approach combines state-of-the-art intermediate-scale flow and transport experiments with an advanced technique for the determination of both the number and activity of contaminant-degrading microorganisms (fiber optic detection of luminescing microorganisms). This approach will allow the simultaneous detection of contaminant transport and microbial activity, which will allow for the investigation of the relationship between spatial heterogeneity and availability of contaminants for microbially-mediated destruction. In addition, the approach will be used to evaluate the physical and biological parameters that control the transport of microorganisms in a heterogeneous environment, and to relate microbial mechanisms for enhanced transport to their potential to enhance the degradation of inaccessible organic contaminants. The approach will also be used to evaluate strategies to enhance in situ bioremediation, for example, the application of surfactants (detergents) that may increase the availability of sorbed contaminants. The results of the research will improve our understanding of these issues and will provide significant advancement in prediction of contaminant transport and fate, for evaluating groundwater contamination potential, and for the manipulation of subsurface systems to enhance the effectiveness of bioremediation technologies.