Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, PR China; Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, PR China.
Advanced interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhuhai 519087, PR China.
J Hazard Mater. 2023 Apr 5;447:130809. doi: 10.1016/j.jhazmat.2023.130809. Epub 2023 Jan 16.
Leakage of light non-aqueous phase liquid (LNAPL) into soil can cause serious environmental issues. In this study, a two-dimensional device with adjustable dip angles was designed to investigate the migration and redistribution of LNAPL in natural inclined stratified soil media by the light transmission visualization (LTV) technology. The captured experimental images were processed to obtain the diesel distribution based on gray value which could represent the LNAPL saturation distribution. LNAPL may not be able to penetrate through the fine-coarse interface due to the capillary barrier effects. In this case, the vertical and horizontal migration distances (V and H), contaminated area (S), as well as deviation angle (γ) of centroid increased with the dip angle. Increasing the leakage amount to more than 30 mL would result in LNAPL breakthrough at the 10°-inclined interface, leading to much larger V, H, S, and γ than those at 10 mL, while 20-mL LNAPL failed to break through. In the latter case, a lower leakage rate than 10 mL/min would cause larger H and γ but similar V or S in the long term. This study could enrich the understanding of LNAPL contamination in vadose zone, providing reference for the prediction and treatment in realistic inclined contaminated sites.
轻非水相液体（LNAPL）渗漏入土壤会造成严重的环境问题。本研究设计了一个具有可调倾斜角度的二维装置，通过透光可视化（LTV）技术研究 LNAPL 在自然倾斜层状土壤介质中的运移和再分布。对采集到的实验图像进行处理，基于灰度值获得柴油分布，灰度值可以代表 LNAPL 饱和度分布。由于毛细屏障效应，LNAPL 可能无法穿透粗细粒界面。在这种情况下，随着倾斜角的增加，垂向和水平迁移距离（V 和 H）、污染面积（S）以及质心的偏离角（γ）会增大。当泄漏量增加到 30 mL 以上时，会导致 LNAPL 在 10°倾斜界面处突破，导致 V、H、S 和 γ 比 10 mL 时大得多，而 20 mL 的 LNAPL 则未突破。在后一种情况下，长期来看，泄漏率低于 10 mL/min 会导致较大的 H 和 γ，但 V 或 S 相似。本研究丰富了对包气带 LNAPL 污染的认识，为实际倾斜污染场地的预测和处理提供了参考。
