ABSTRACT
Considerable concern is given to the contamination of the environment; especially in areas with high concentrations of organic materials and heavy metals. Theses contaminated sites are of potential risk for the groundwater quality. Contamination sources include leaching of agricultural fertilizers and pesticides, leakage from sewers and sewage systems, and spills from underground storage tanks. Some of these pollutants are biodegradable, such that natural filtration and adsorption may remove part of unsuitable present organisms. On the other hand, chemical contaminants are of persisting nature and thus are more hazardous. In this paper, a mathematical/numerical model is developed to simulate the transport and fate of Non-Aqueous Phase Liquids (NAPLs) in near-surface granular soils. The movement of NAPLs through porous medium can be described by a coupled set of nonlinear partial differential equations that are generated by combining balance equations with constitutive relationships. Two-phase coupled flow, including mass transfer effects, is considered. The behavior of NAPLs through groundwater aquifers is presented, which may help identify the proper remediation. The developed model is used to investigate pollution behavior through saturated zones. Plume migration is presented for two different cases, first when continuous slow rate of NAPL reaches the water table and second when a large volume of NAPL suddenly reaches the water table over relatively short time.
