石油污染土壤电动-微生物修复有机碳代谢机制与调控研究

Electrokinetics-bioremediation was used to remediate the petroleum contaminated soil, the synchronous metabolic characteristics of petroleum-derived organic carbon and natural soil organic carbon (SOC) were researched, using 13C stable isotope method. Metabolic differences between heterologous organic carbon under different electric field modes (such as constant field intensity and polarity-reversal) and in different sections (such as the anode area and cathode area) were researched. The variance of isotopic 13C abundance in petroleum and petroleum group components by column chromatography technique were measured at the same time. The physicochemical properties and microbial physiological characteristics in soil micro environment were monitored which would be changed with the treatment process by the soil chemical analysis technology, high-throughput sequencing technology and substrate-induced soil respiration monitoring method. The correlation between organic carbon metabolic characteristics and soil micro environment variables was analyzed by redundancy analysis (RDA) and principal component analysis (PCA) and other statistical means. The structural equation modeling (SEM) between environmental variables and organic carbon metabolism would be constructed with Amos software. The significance of natural soil organic carbon in the process of electrokinetics-bioremediation of petroleum was analyzed in depth. The consumption ratio of petroleum-derived organic carbons to natural soil organic carbon (SOC) was chosen as an evaluation index of electro-bioremediation technology, to elucidate the restore efficiency of electrokinetics-bioremediation in different application modes and the efficiency variances in different treatment areas systematically. The method of the soil organic carbon regulation for electro-bioremediation system will be constructed.

以电动-微生物修复石油污染土壤为研究对象，采用碳13稳定同位素方法进行污染土壤石油源有机碳与土壤天然有机碳（SOC）同步代谢特征分析，研究不同电场施加方式（如恒定场强与倒极）及不同电场区域内（如阳极区与阴极区）异源有机碳的代谢差异性及石油样品的同位素丰度值的变化特征。采用土壤化学分析技术、高通量二代测序技术及底物诱导土壤呼吸等方法监测土壤微环境指标变化。利用冗余分析（RDA）和主成分分析（PCA）统计学手段深入挖掘土壤微环境因子参数与有机碳代谢特征相关性。使用Amos软件构建环境因素变量与有机碳代谢特征间的结构模型（SEM），深度分析土壤天然有机碳在电动-微生物修复降解石油污染物过程中的重要意义。以石油有机碳与土壤有机碳（SOC）消耗比例作为电动-微生物修复技术评估指标，系统阐述电动-微生物技术对石油污染土壤的修复在不同应用方式下的整体修复效率以及在不同修复区域内的修复效率变化，建立电动-微生物修复体系的土壤有机碳调控方法。

有机碳的代谢与降解是电动-微生物修复石油污染土壤的核心问题。土壤有机碳与石油源有机碳是油污土壤的两大碳源类型，随着修复过程的进行，两类碳源呈现不断变化的降解特征，这种动态的碳源降解模式与电动条件下的土壤理化性质及土壤微生物学指标密切相关。相关的研究结果表明，通过高通量筛选法获得的功能微生物在电动修复条件下呈现良好的与电动处理协同的石油降解特性。在恒定场强方向与倒极条件下，处理土壤分别呈现特异性的理化特征，并由此形成阳极区化学氧化区与阴极区生物降解区的功能分区。石油烃的族组分分析表明，饱和烃和芳香烃是主要的降解组分，其中饱和烃组分中随着碳数范围的增加，可降解性逐渐减弱。采用13C同位素技术分析土壤有机碳与石油源有机碳降解特征，石油源有机碳与土壤有机碳的降解比例（P/S）呈现由高到低的动态变化特征，微生物代谢比电化学氧化作用具有更强的土壤源有机碳消耗能力。电流强度对微生物代谢石油烃污染物的刺激作用强于对土壤有机碳消耗的影响。极性切换处理的总体石油碳与土壤碳降解量之比（P/S）大于不切换处理组。微生物学指标分析表明，在适宜的土壤条件下，电动作用促进了土壤总体细菌及石油烃降解功能微生物的丰度与多样性的维持，土壤中微生物群落组成的分布特征与土壤中有机碳及石油源有机碳的属性关系最为密切，并在不同电场区域内形成特异性优势菌属。土壤微生物功能多样性分析表明，不同电动处理条件下呈现出功能多样性分布的差异性与石油不同组分代谢的倾向性。有机碳代谢功能指标揭示，土壤SOC与石油源有机碳的消耗量比例（P/S）小于1.5时，通过向土壤中分别补给原始土壤DOC和协同底物碳源（本实验中为丙酮酸），总补给量达到初始土壤SOC含量的80%~150%，实现对电动-微生物联合修复石油污染土壤过程的调控应用。本项目在研期间共发表文章5篇，其中SCI 3篇，授权专利2项。本项目核心成果在辽河油田和胜利油田石油污染土壤修复工程中得到应用和推广。