电动传输硝态氮强化油污土壤原位生物修复的关键因素及其调控

Poor permeability of soil would be easily deduced by combination of petroleum contaminant and soil particles, and influenced the transportation of microorganism and nutrition. The author suggested that nitrogen deficiency was the crucial limitation of in-situ bio-remediation technology of polluted soil, which could be compensated by electrokinetic technique. Therefore, this study took actual petroleum polluted soil as object and proposed electrokinetic as additional advanced technique of in-situ bio-remediation technology by enhancing transportation of nitrate. The influences of some key factors (including characters of electrode, electric intensity, and transmission conditions) on distributions and transformations of nitrate in different three phases (including aqueous phase, soil, and microorganism) were investigated. The abiological transporting loss of and nitrate effective reduction ways were studied. The transfer and loss of regional microbial degradation ability deduced by concomitant transfer of indigenous communities in electrokinetic process of nitrate, and effective replenishment strategies were then established. This study promoted the applications of in-situ bio-remediation technology and provide promising refers for remediation of actual petroleum polluted soil.

石油烃类污染物进入土壤后容易与土壤颗粒结合造成土壤的低渗透性，阻碍了微生物及营养物质的传输。申请者在前期的研究中发现氮源不足是限制微生物原位修复技术应用的关键问题之一，而电动力学过程被证实是在低渗透性土壤中可以有效传输菌体及营养物质。基于此，本项目以实际油污土壤为处理对象，提出采用电动传输硝态氮强化微生物原位修复效率，围绕其中的关键影响因素，从电化学角度系统考察电极性能、电场强度、传输条件等致变因子对硝态氮在水、土壤及微生物三相间分配转化的影响并掌握实现有效传输的调控原理；阐明基于非生物作用硝态氮电动传输损失的产生过程并确定有效的削减方式，从种群层面准确解析硝态氮电动传输过程中土著微生物种群的伴随迁移行为引发的区域微生物降解活性迁移、损失并建立有效的补给策略。本研究将促进微生物原位修复技术应用的成熟化和系统化，为实现油污土壤的高效修复提供具有实际参考价值的依据。

本项目围绕油污染土壤修复开展研究，通过强化油污染土壤中的生物反硝化作用来提高修复效率。首先采用电化学手段实现了将硝酸盐氮迁移至土壤中，确定了硝酸盐氮的电迁移机制并优化了电迁移条件；其次，筛选了具有高效石油烃降解能力的反硝化菌株，阐明了石油烃的代谢机制并优化了菌株的降解条件，同时筛选了能够在非诱导条件下实现高效产脂肽菌株，该脂肽对典型污染物菲和十六烷具有显著的增溶能力，为上述反硝化菌株降解石油烃过程提供了生物表面活性剂；为了防止污染物在土壤中的垂直迁移，首次通过电化学技术同步输送钙离子和碳酸根来构建原位低渗透屏障，阐明了低渗透屏障的形成机制及对典型污染物迁移的控制机理。该技术可以为石油烃类污染物修复周期长提供很好的缓冲，具有潜在的应用价值。