Unsaturated flow effects on solute transport in porous media

• Autor(a) principal: Zhuang, Luwen
• Data de Publicação: 2021
• Outros Autores: Raoof, Amir, Mahmoodlu, Mojtaba G., Biekart, Sara, de Witte, Riemer, Badi, Lubna, van Genuchten, Martinus Th. [UNESP], Lin, Kairong
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1016/j.jhydrol.2021.126301; http://hdl.handle.net/11449/206201
• topic: Dispersion; Dispersivity; Solute transport; Unsaturated zone

A major contaminant transport process in soils is hydrodynamic dispersion by affecting the spreading and arrival of surface-applied pollutants at underlying groundwater reservoirs. When a soil is unsaturated, hydrodynamic dispersion is very much affected by soil water saturation. Centimeter- and decimeter-scale column experiments were carried out to explore the effects of fluid saturation and particle size on the unsaturated solute dispersivity. Measured in-situ breakthrough curves were analyzed in terms of both classical advection–dispersion and dual-porosity (mobile-immobile) type transport equations. A clear non-monotonic relationship was found between the dispersivity and soil water saturation. The extent of non-monotonicity was more pronounced for a relatively coarse-textured sand compared to a finer sand. This finding has been reported rarely before; it explains some of the inconsistencies of saturation-dispersivity relationships in the literature.