基于TMVOC的地下水位波动带苯系物迁移转化模拟

为探究水位波动情况下苯系物的迁移转化规律，提高石油污染场地地下水污染治理精度，以西北某傍河石化场地为研究对象，基于TMVOC模型对特征污染物苯系物开展泄漏模拟，通过情景模拟比较水位波动对苯系物迁移转化的影响，并从污染分布、相间转化等方面，解析地下水位稳定和波动状态下苯系物迁移转化过程差异.结果表明:①TMVOC模型较好地模拟了水位波动状态下苯系物迁移转化过程.②相较于水位稳定状态下，水位波动作用下苯系物污染深度增加0.5 m，污染面积增加25%，总质量增加12 kg.③水位稳定和波动状态下苯系物"气-液-NAPL（Non-Aqueous Phase Liquids）相"占比分别为0.17%、2.03%、97.8%和0.04%、3.69%、96.27%.④NAPL相苯系物饱和度分布与苯系物质量分布呈正相关，水位波动造成NAPL相初始饱和度降低，且初始水位面以下NAPL相饱和度升高.⑤对于苯而言，水位波动状态下非饱和带中苯在液相中的质量是水位稳定状态下的1.11倍，饱和带为10.15倍.研究显示，水位波动显著地影响了苯系物的迁移转化过程，促进了苯系物的溶解，并使更多的苯系物残留在地下介质中. 

Numerical Simulation of BTEX Migration in Groundwater Table Fluctuation Zone Based on TMVOC

Studying the BTEX migration and transformation in subsurface under groundwater table fluctuation (GTF) will provide more accurate contamination plume for groundwater pollution remediation. A riverside petrochemical site was selected as the object, and BTEX migration in the subsurface under GTF was simulated by the TMVOC model. The difference of BTEX migration process under GTF and stable groundwater table (SGT) was analyzed by contaminant pollution distribution and transformation among gas-aqueous-NAPL (Non-aqueous Phase Liquids) phases. The results showed that:(1) TMVOC model simulated BTEX migration and transformation process of the riverside petrochemical site under GTF. (2) Comparing with the SGT, BTEX pollution plume depth increased by 0.5 m and the area increased by 25%, and the total mass was higher by 12 kg under GTF. (3) The ratio of BTEX in the gas phase, aqueous phase and NAPL phase was 0.17%, 2.03% and 97.8% under SGT and 0.04%, 3.69%, 96.27% under GTF. (4) The NAPL phase saturation distribution was positively correlated with BTEX mass fraction distribution. The GTF led to NAPL phase initial saturation decreased and saturation increased below initial groundwater table. (5) Under the GTF, the mass of benzene in the aqueous phase was 1.11 times in the unsaturated zone and 10.15 times in the saturated zone than that with the SGT. The GTF obviously promoted BTEX migration and dissolution into groundwater, and resulted in more BTEX to remain in the subsurface at the site.