利用趋化细菌修复非均质地下水系统中石油污染的机理研究

Aromatic hydrocarbons from oil contamination are easy to spread and quite difficult to remove in the groundwater environment, therefore, developing economic and efficient in-situ remediation methods becomes an important topic in the field of environmental protection. Due to the relatively narrow porous structure and poor hydraulic conductivities in the polluted layer of groundwater system, the current remediation methods can barely contact the contaminant sources, and the cleanup efficiencies are generally low. Chemotactic bacteria can quickly accumulate around the contaminant sources, thoroughly degrade the aromatic hydrocarbons, and fast grow upon the substrates; in addition, they are environmentally friendly. Adopting these bacteria can dramatically reduce cost and enhance the cleanup efficiency. Microfluidic technique is chosen to mimic contaminated groundwater environment in this study. This novel method can accurately capture the micro-scale structures in the groundwater system, and the essential parameters in the microfluidic device, including pore sizes, porosity, tortuosity, and heterogeneity, all agree with the criteria in reality; microfluidics can also transfer the black-box-like porous structure into a transparent platform, so it becomes possible that one can observe the chemotactic effect in adjacent to the contaminants within a porous medium in real time. This method is also proved to be repeatable and quantitative based on the present research findings, and with the help of numerical simulation on multiple physical and chemical modules, this study can reveal the mechanism of bacterial chemotaxis in oil contamination in the groundwater environment, and provide the research basis to achieve economic and efficient in-situ bioremediation method.

石油污染事故中的芳烃类物质在地下水环境中易扩散且极难清除，研发低能高效的原位修复方法是环保领域的重要课题。由于浅层地下水环境中的污染层孔径细密、水导性差，现行修复手段难以达到污染区域，致使清洁效率欠佳。趋化细菌具有在污染源附近迅速富集、彻底降解芳烃类物质、快速增殖等优点，且对环境无毒副作用，可大幅降低环境修复成本，提高污染清理效率。本项目采用微流控技术模拟受污染的地下水环境，可以准确地复制地下水系统的微观结构，微流控芯片中的孔径大小、孔隙率、迂曲度、异质化结构等重要参数均符合真实标准；微流控技术还可将 “黑盒式”的多孔结构“透明化”，实现在多孔介质中对石油污染物周围的趋化效应的实时检测。现有工作基础还表明该方法具有重复率高、检测定量化等优点，结合多物理化学场耦合的数值模拟手段，本项目可揭示细菌在石油污染的地下水环境中的趋化机理，为实现低能高效的原位生物修复技术提供研究基础。

石油污染事故中的芳烃类物质在地下水环境中易扩散且极难清除，研发低能高效的原位修复方法是环保领域的重要课题。由于浅层地下水环境中的污染层孔径细密、水导性差，现行修复手段难以达到污染区域，致使清洁效率欠佳。趋化细菌具有在污染源附近迅速富集、彻底降解芳烃类物质、快速增殖等优点，且对环境无毒副作用，可大幅降低环境修复成本，提高污染清理效率。本项目采用了微流控技术模拟受污染的地下水环境，可以准确地复制地下水系统的微观结构，微流控芯片中的孔径大小、孔隙率、迂曲度、异质化结构等重要参数均符合真实标准；微流控技术还可将 “黑盒式”的多孔结构“透明化”，实现在多孔介质中对石油污染物周围的趋化效应的实时检测。本研究表明该方法重复率高、检测易量化，并结合多物理化学场耦合的数值模拟和量纲分析，揭示了细菌在石油污染的地下水环境中的趋化机理，为实现低能高效的原位生物修复技术提供了研究基础。