Migration and redistribution of LNAPL in inclined stratified soil media

Didi Li; Dacheng Cai; Zhimin Ao; Xi Jiang

doi:10.1016/j.jhazmat.2023.130809

Migration and redistribution of LNAPL in inclined stratified soil media

J Hazard Mater. 2023 Apr 5:447:130809. doi: 10.1016/j.jhazmat.2023.130809. Epub 2023 Jan 16.

Authors

Didi Li¹, Dacheng Cai¹, Zhimin Ao², Xi Jiang³

Affiliations

¹ 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.
² Advanced interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhuhai 519087, PR China.
³ School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, UK. Electronic address: xi.jiang@qmul.ac.uk.

PMID: 36680902
DOI: 10.1016/j.jhazmat.2023.130809

Abstract

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.

Keywords: Dip angle; Fine-coarse soil media; LNAPL; Migration and redistribution; Vadose zone.