Study on Influence of Geological Heterogeneity on Migration of LNAPL in Contaminated Site Through Numerical Analysis
The migration behaviour and long-term distribution of Light Nonaqueous Phase Liquids (LNAPLs) are greatly influenced by the geological conditions of the sites. In order to investigate the influence of geological heterogeneity on it, the migration process of LNAPLs in a two-dimensional site was numerically studied in this research. Typical conditions including one homogeneous soil layer, multi-layered strata and lens of clayey soil were specially considered. Calculation results indicate that the contour map of the mass ratio of LNAPLs gradually develops from a circular area into an umbrella area if it is leaked from a point source such as underground storage tank. Once the contaminant front of the LNAPLs arrives at the margin of the capillary saturated zone, their horizontal migration distance reaches the maximum value. When lens of low permeability soil area exists, it can effectively prevent the downward migration and promote the horizontal migration of LNAPLs. In the case of multiple sand layers, the migration behaviour of LNAPLs is mainly affected by the permeability of each layer of sand. Lower permeability soil layer will not only slow down the vertical movement of LNPLs, but also promotes their horizontal migration. Such results may help to scientifically design the vertical barriers and determine the optimum soil vapour extraction systems according to the geological heterogeneity of the real sites.
KeywordsLNAPL Geological heterogeneity Migration of contaminants Contaminated site Numerical analysis
This work was supported by the National Natural Science Foundation of China (Project No. 41672280, 41330641).
- 2.Li YT (2010) Study on migration mechanism and simulation of light nonaqueous-phase liquids in vadose zone. Chang’an University, Xian. (in Chinese)Google Scholar
- 3.Pruess K, Oldenburg C, Moridis G (1999) TOUGH2 user’s guide, version 2.0. Berkeley National Laboratory Report, BerkeleyGoogle Scholar
- 4.Fang W (2015) Laboratory experimental research on remediation of MTBE-contaminated saturated sand by surfactant-enhanced air sparing. Southeast University, Nanjing. (in Chinese)Google Scholar
- 7.Xing WW (2005) Study on migration behavior of LNAPLs in soils. Tsinghua University, Beijing. (in Chinese)Google Scholar
- 8.Shi XQ, Wu JC, Yuan YS (2006) Study on the spatial variability of hydraulic conductivity. Adv Environ Sci 16(2):210–215 (in Chinese)Google Scholar
- 9.Wu XF, Tang J (1999) Capillary pressure and relative permeability of three-phase flow in porous media. Adv Environ Sci 7(5):68–73 (in Chinese)Google Scholar
- 10.Peng W, Wu JF, Yan TT (2008) Uncertainty analysis of the contaminant transport fate using conditional simulation of hydraulic conductivity. J Nanjing Univ 44(3):280–288 (in Chinese)Google Scholar