Contaminant transport in groundwater in the presence of colloids and bacteria: Model development and verification

• Published in: Journal of contaminant hydrology 2009-09, Vol.108 (3), p.152-167
• Main Authors: Bekhit, Hesham M., El-Kordy, Mohamed A., Hassan, Ahmed E.
• Format: Article
• Language: English
• Subjects: Bacteria; Bacteria-associated transport; Colloid-associated transport; Colloids; Constituents; Contaminants; Earth sciences; Earth, ocean, space; Environmental Microbiology; Environmental Monitoring; equations; Exact sciences and technology; Groundwater; Groundwater contaminant transport; groundwater contamination; groundwater flow; Hydrogeology; hydrologic models; Hydrology. Hydrogeology; mass transfer; Mathematical analysis; Mathematical models; Models, Theoretical; Movement; pollutants; porous media; Subsurface transport modeling; Water Movements; Water Pollutants, Chemical - analysis
• ISSN: 0169-7722; 1873-6009
• DOI: 10.1016/j.jconhyd.2009.07.003

Colloids and bacteria (microorganisms) naturally exist in groundwater aquifers and can significantly impact contaminant migration rates. A conceptual model is first developed to account for the different physiochemical and biological processes, reaction kinetics, and different transport mechanisms of the combined system (contaminant–colloids–bacteria). All three constituents are assumed to be reactive with the reactions taking place between each constituent and the porous medium and also among the different constituents. A general linear kinetic reaction model is assumed for all reactive processes considered. The mathematical model is represented by fourteen coupled partial differential equations describing mass balance and reaction processes. Two of these equations describe colloid movement and reactions with the porous medium, four equations describe bacterial movement and reactions with colloids and the porous medium, and the remaining eight equations describe contaminant movement and its reactions with bacteria, colloids, and the porous medium. The mass balance equations are numerically solved for two-dimensional groundwater systems using a third-order, total variance-diminishing scheme (TVD) for the advection terms. Due to the complex coupling of the equations, they are solved iteratively each time step until a convergence criterion is met. The model is tested against experimental data and the results are favorable.