| Title: | Transient migration behavior of VOC vapor in layered unsaturated soils subjected to multiple time-dependent point pollution sources: Analytical study |
| Author(s): | Ding XH; Feng SJ; Zheng QT; Peng CH; Zhu ZW; Yang CB; |
| Address: | "Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China. Electronic address: 1732201@tongji.edu.cn. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China; Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education, Tongji University, Shanghai 200092, China. Electronic address: fsjgly@tongji.edu.cn. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China. Electronic address: 08qitengzheng@tongji.edu.cn. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China" |
| DOI: | 10.1016/j.scitotenv.2021.150370 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "Predicting the migration behavior of volatile organic compounds (VOCs) vapor is essential for the remediation of subsurface contamination such as soil vapor extraction. Previous analytical prediction models of VOCs migration are mostly limited to constant-concentration nonpoint sources in homogeneous soil. Thus, this study presents a novel analytical model for two-dimensional transport of VOCs vapor subjected to multiple time-dependent point sources involving transient diffusion, sorption and degradation in layered unsaturated soils. Two representative time-dependent sources, i.e., an instantaneous source and a finite pulse source, are used to describe the short-term and long-term leakage. Results reveal that soil heterogeneity can cause pollution accumulation, especially in low-diffusivity capillary fringe. The assumption of an equivalent plane source from multiple point sources would significantly overestimate the vapor concentration and the contaminated range. The previous single point source model is no longer inapplicable when the relative distance and/or the release interval between sources is small, giving a strong interaction between multiple sources. Moreover, a faster vapor degradation rate or a higher groundwater level will reduce the area of vapor plume linearly. Hence, close attention should be paid to the time-variation characteristics of multiple sources, the vapor degradation and the groundwater level fluctuation in practice to facilitate soil remediation. The proposed model is a promising tool for addressing the above issue" |
| Keywords: | Environmental Pollution Gases *Groundwater Soil *Soil Pollutants/analysis *Volatile Organic Compounds Biodegradation Layered unsaturated soil Multiple point sources Time-dependent release Two-dimensional migration of VOC vapor; |
| Notes: | "MedlineDing, Xiang-Hong Feng, Shi-Jin Zheng, Qi-Teng Peng, Chun-Hui Zhu, Zhang-Wen Yang, Chun-Bai-Xue eng Netherlands 2021/09/26 Sci Total Environ. 2022 Feb 1; 806(Pt 1):150370. doi: 10.1016/j.scitotenv.2021.150370. Epub 2021 Sep 17" |
