耐重金属高效多环芳烃降解菌群强化雨水生物滞留系统的机制研究

Polycyclic aromatic hydrocarbons (PAHs), a class of toxic environmental pollutants with low biodegradability, contribute significantly to the contamination of urban stormwater runoff in China. During the treatment of stormwater runoff with bioretention systems, removal efficiency and accumulation effect of PAHs retained in the system need to be further clarified. By applying bioaugmentation technology, the proposed study will add metal-resisting high-efficiency PAHs-degrading microbial consortium into bioretention system for urban runoff, so as to optimize PAHs degradability, illustrate correlative factors and mechanisms, and finally reduce the high load of PAHs accumulated in this complex system. Moreover, specialized metal-resisting PAHs-degrading microbial strains will be selectively enriched and separated from petroleum hydrocarbon-contaminated soil with amended bioaugmentation technique, and then combined to prepare high-efficiency PAHs-degrading microbial consortium of which the biodegradation mechanisms and pathways will be studied through metabolites analyses and molecular biology techniques. Finally, small-scale bioaugmented bioretention system for urban stormwater runoff will be established, and its removal capacity for PAHs and stability will be investigated. Factors of different microbial consortium dosing ways, design parameters, and road runoff characteristics will then be evaluated for their impact on system performance of PAHs removal. The proposed research will shed light on the mechanisms and enhancement effect of PAHs removal in bio-augmented bioretention system under combined pollution of heavy metals and PAHs, and thus providing theoretical and intellectual support for the bioremediation of PAHs diffused contamination in urban areas and making contribution to the achievement of regional sustainable development of ecological system, society and economy in China.

多环芳烃（PAHs）作为难降解有毒污染物，是我国城市雨水径流中的重要组成。在利用生物滞留系统处理径流污染过程中，被截留PAHs的去除效果及积累问题有待研究。本研究利用生物强化技术，向生物滞留系统中投加耐重金属高效PAHs降解菌群，优化PAHs降解能力，探索其影响因素和作用机制，以解决复合污染条件下PAHs类污染物的积累问题。采用改良的实验室强化培养方法，构建以关键功能菌株为主体的耐重金属高效PAHs降解菌群，通过代谢产物分析和分子生物学手段揭示菌群的协同作用机理和代谢途径；使用小试装置构建强化生物滞留系统，考察其PAHs降解能力和稳定性，探索菌群投加方式、滞留系统设计参数和路面径流特点等因素对PAHs净化效果的影响，并揭示重金属-PAHs复合污染条件下强化生物滞留系统对PAHs的削减情况和影响机制，从而为解决城市水体环境中PAHs面源污染问题提供理论支持和技术保障。

多环芳烃（PAHs）作为难降解的持久性有机污染物，是我国城市雨水径流中的重要组成。在利用生物滞留系统处理径流污染过程中，被截留的PAHs有可能产生积累问题和潜在环境风险。采用生物强化技术向生物滞留系统中投加高效PAHs降解菌剂，是一种值得研究和应用的降低PAHs污染危害的新方法。本研究在整理前人研究的基础上，归纳总结了生物滞留设施去除PAHs的效果、机理及其主要影响因素；对受PAHs污染土壤中微生物进行驯化与筛选，构建了以关键功能菌株为主体的耐重金属高效PAHs降解菌群；利用分子生物学手段掌握了菌群多样性和群落结构信息，并对高效菌群的生长和降解特性进行了分析，结合动力学模型考察和确定了菌群生长和PAHs降解活性的耐受范围和最佳条件；构建生物滞留系统小试装置，探明了不同PAHs胁迫压力对不同填料组成生物滞留系统处理性能、微生物酶活、多样性及群落结构的影响，揭示了系统对PAHs的耐受性和微生物群落动态演变规律。项目的研究成果可应用于生物滞留系统的改良和生物修复，为解决城市雨水径流中PAHs污染问题、优化生物滞留系统运行提供了一定的理论基础和技术支撑。