Effect of Water Content on Light Nonaqueous Phase Fluid Migration in Sandy Soil
Contamination from light nonaqueous phase fluids (LNAPLs) and their derivatives during mining, production, and transportation has become a concern. Scholars have extensively studied LNAPL contamination, but the role of water content variation on its migration process in the unsaturated zone has not...
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2024-10-01
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| author | Guizhang Zhao Jiale Cheng Leicheng Li Hongli Zhang Hongliang Li Hepeng Zhang |
| author_facet | Guizhang Zhao Jiale Cheng Leicheng Li Hongli Zhang Hongliang Li Hepeng Zhang |
| author_sort | Guizhang Zhao |
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| description | Contamination from light nonaqueous phase fluids (LNAPLs) and their derivatives during mining, production, and transportation has become a concern. Scholars have extensively studied LNAPL contamination, but the role of water content variation on its migration process in the unsaturated zone has not been sufficiently researched. The specific issue addressed in this study is the impact of water content on the migration of light nonaqueous phase liquids (LNAPLs) in sandy soils, a critical yet under-researched aspect of subsurface contamination. To tackle this, we employed indoor simulated vertical, one-dimensional, multiphase flow soil column experiments, utilizing the orthogonal experimental method to systematically evaluate the effects of varying water contents on the occurrence state and migration rate of LNAPLs. The experimental results indicate the following: (1) The migration rate of LNAPL exhibits an L-shaped trend during subsurface imbibition and a nonlinear relationship with migration time. The migration rate and migration time of surface infiltration have a linear growth relationship. (2) The residual rate of LNAPL is negatively correlated with water content and positively correlated with oil content in the homogeneous non-saturated state. With the increase in the amount of leaked oil, 40% of the leaked LNAPL is sorbed within the soil. (3) When the water content of the test medium is below 14%, and the oil content is below 11%, LNAPL appears in the unsaturated zone in a solid phase. As the water content increases, the adsorption rate of the oil phase gradually decreases and eventually reaches the oil saturation point. (4) When the water content of the medium exceeds 8%, over time, LNAPL will be subject to oil–water interfacial tension, and the rate of LNAPL movement first decreases and then increases, displaying nonlinear growth. The innovation of this work lies in the comprehensive analysis of LNAPL migration under controlled laboratory conditions, providing results that enhance the understanding of LNAPL behavior in sandy soils. These quantitative insights are crucial for developing targeted remediation strategies for LNAPL-induced pollution in the unsaturated zone. |
| format | Article |
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| institution | Kabale University |
| issn | 2076-3417 |
| language | English |
| publishDate | 2024-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj-art-12796f664ed14b6b890bbf5a6767affb2024-11-08T14:32:51ZengMDPI AGApplied Sciences2076-34172024-10-011421964010.3390/app14219640Effect of Water Content on Light Nonaqueous Phase Fluid Migration in Sandy SoilGuizhang Zhao0Jiale Cheng1Leicheng Li2Hongli Zhang3Hongliang Li4Hepeng Zhang5Earth Geosciences and Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450045, ChinaEarth Geosciences and Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450045, ChinaEarth Geosciences and Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450045, ChinaEarth Geosciences and Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450045, ChinaEarth Geosciences and Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450045, ChinaEarth Geosciences and Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450045, ChinaContamination from light nonaqueous phase fluids (LNAPLs) and their derivatives during mining, production, and transportation has become a concern. Scholars have extensively studied LNAPL contamination, but the role of water content variation on its migration process in the unsaturated zone has not been sufficiently researched. The specific issue addressed in this study is the impact of water content on the migration of light nonaqueous phase liquids (LNAPLs) in sandy soils, a critical yet under-researched aspect of subsurface contamination. To tackle this, we employed indoor simulated vertical, one-dimensional, multiphase flow soil column experiments, utilizing the orthogonal experimental method to systematically evaluate the effects of varying water contents on the occurrence state and migration rate of LNAPLs. The experimental results indicate the following: (1) The migration rate of LNAPL exhibits an L-shaped trend during subsurface imbibition and a nonlinear relationship with migration time. The migration rate and migration time of surface infiltration have a linear growth relationship. (2) The residual rate of LNAPL is negatively correlated with water content and positively correlated with oil content in the homogeneous non-saturated state. With the increase in the amount of leaked oil, 40% of the leaked LNAPL is sorbed within the soil. (3) When the water content of the test medium is below 14%, and the oil content is below 11%, LNAPL appears in the unsaturated zone in a solid phase. As the water content increases, the adsorption rate of the oil phase gradually decreases and eventually reaches the oil saturation point. (4) When the water content of the medium exceeds 8%, over time, LNAPL will be subject to oil–water interfacial tension, and the rate of LNAPL movement first decreases and then increases, displaying nonlinear growth. The innovation of this work lies in the comprehensive analysis of LNAPL migration under controlled laboratory conditions, providing results that enhance the understanding of LNAPL behavior in sandy soils. These quantitative insights are crucial for developing targeted remediation strategies for LNAPL-induced pollution in the unsaturated zone.https://www.mdpi.com/2076-3417/14/21/9640light nonaqueous phase fluids (LNAPLs)adsorption ratewater contentoil contentunsaturated state |
| spellingShingle | Guizhang Zhao Jiale Cheng Leicheng Li Hongli Zhang Hongliang Li Hepeng Zhang Effect of Water Content on Light Nonaqueous Phase Fluid Migration in Sandy Soil Applied Sciences light nonaqueous phase fluids (LNAPLs) adsorption rate water content oil content unsaturated state |
| title | Effect of Water Content on Light Nonaqueous Phase Fluid Migration in Sandy Soil |
| title_full | Effect of Water Content on Light Nonaqueous Phase Fluid Migration in Sandy Soil |
| title_fullStr | Effect of Water Content on Light Nonaqueous Phase Fluid Migration in Sandy Soil |
| title_full_unstemmed | Effect of Water Content on Light Nonaqueous Phase Fluid Migration in Sandy Soil |
| title_short | Effect of Water Content on Light Nonaqueous Phase Fluid Migration in Sandy Soil |
| title_sort | effect of water content on light nonaqueous phase fluid migration in sandy soil |
| topic | light nonaqueous phase fluids (LNAPLs) adsorption rate water content oil content unsaturated state |
| url | https://www.mdpi.com/2076-3417/14/21/9640 |
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