Application of nonequilibrium fracture matrix model in simulating reactive contaminant transport through fractured porous media

Abstract

Nonequilibrium and nonlinear sorption of the contaminants in the fractured porous media could significantly influence the shape of the breakthrough curve (BTC). For the fracture-matrix system, there are very few studies which consider these processes. In this study, the nonequilibrium fracture-matrix model with two different nonlinear sorption isotherms, namely nonlinear Freundlich and Langmuir sorption isotherms were developed. The effect of sorption nonlinearity and nonequilibrium conditions on the shape of the BTC was studied using the temporal moments. The developed models along with the linear equilibrium, linear nonequilibrium fracture matrix models, and the multirate mass transfer model were used to simulate the BTC, which were compared with the experimental data available in the literature. Both sorption nonequilibrium and nonlinearity were found to significantly influence the shape of the BTC. Presence of sorption nonlinearity reduces the solute spreading, whereas presence of nonequilibrium conditions increases the solute spreading. Considering the sorption nonequilibrium along with the sorption nonlinearity leads to an improved simulation of the BTC. The nonequilibrium nonlinear sorption models could simulate the extended BTC tailing resulting from sorption nonlinearity and rate-limited interaction in the fracture-matrix system.

Non-reactive solute transport modelling with time-dependent dispersion through stratified porous media

“…It has been reported in literature that ADE is less adequate for simulating anomalous transport through heterogeneous porous media [3,[5][6][7][8][9]. Therefore, higher-order modelling approaches have been proposed that can capture anomalous transport behaviour of solute, considering physical and chemical partitioning in saturated porous media [8,[10][11][12][13][14][15]. Physical partitioning results from the hydraulic coupling of mobile (advective) and immobile (nonadvective) regions such as stratified porous media, in which the former behaves as sink/source component.…”