A NON-FICKIAN SURFACE EXCESS MODEL FOR CHEMICAL-TRANSPORT THROUGH FRACTURED POROUS-MEDIA

The transport of a solute through fractured rock domains is of major c oncern in various disciplines. The transport of chemicals in a porous medium is not a very well understood phenomenon, especially if the mei dum is fractured. A study was conducted to invertigate the transport p rocess of three selected chemicals in a fractured porous medium. A ser ies of laboratory flow experiments was conducted in silica sand packs using a single fracture. Forty six runs were conducted to investigate the effects of chemical concentration, flow rate, and fractures in the transport process. A numerical model was developed that employed a on e-dimensional transport equation combined with the surface excess conc ept to describe absorption equilibrium in the solid/liquid interface. Functional forms of the dispersion parameter (lambda) and the kinetic desorption constant (k(2)) were used to take into account the effect o f the fracture on the porous medium. This non-fickian simulation resul ts showed excellent agreement with experimental results. The developed model accommodates various interactions between the solid and the liq uid phases. Therefore, it can be used for different chemical and rock types with little modification.