Engineering Proceedings (May 2023)
Simulation of One-Dimensional Solute Transport with Equilibrium-Controlled Non-Linear Sorption Using Modular Three-Dimensional Multispecies Transport Model
Abstract
Groundwater contamination is a rising issue worldwide, and it must be treated well as most of the world relies on it. Groundwater pollution occurs when undesirable substances in groundwater rise. Understanding, simulating, and predicting solute mobility in groundwater helps to treat polluted groundwater. MT3DMS has been used to model contaminant movement with a non-linear Freundlich sorption isotherm. MT3DMS stands for “Modular three-dimensional multispecies transport model”. MT3DMS software has several categories of solute transport solution techniques, like FDM and the higher-order finite-volume TVD method, in a unique single code. Applying the combination of these solution techniques is believed to give the best possible solution with greater precision and accuracy. In the current work, the benchmark problem (P2) of the MT3DMS package was taken, and the chemical reaction package was modified according to our problem. Multiple simulations were run with different adsorption capacities and intensities, incorporating the nonlinear Freundlich sorption isotherm. After that analysis of BTC trends, at a position 8 cm from the source, the pulse input of contamination was discharged for 160 s. The simulation lasted 1500 s. The observation output files were imported to plot BTCs for trend analysis and visualize simulation results. After comparing the various BTCs, it was found that the adsorption capability of porous medium enhances retention capacity so contaminants are sorbed and retarded by the solid phase more, slowing the contaminant movement and delaying the BTC peak. For similar adsorption capacity at a lower adsorption intensity, the solid retains more contaminant and the peak is attenuated as well as delayed; but, as the adsorption intensity increases, the relative concentration in the aqueous phase increases, and the peak is enhanced early as the solid retains less contaminant.
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