Title

A Reaction-Based Paradigm To Model Reactive Chemical Transport In Groundwater With General Kinetic And Equilibrium Reactions

Keywords

Equilibrium reactions; Finite element method; Fully-implicit; Groundwater quality; Kinetic reactions; Lagrangian-Eulerian approach; Operator-splitting; Predictor-corrector; Reactive transport modeling; Uranium sorption

Abstract

This paper presents a reaction-based water quality transport model in subsurface flow systems. Transport of chemical species with a variety of chemical and physical processes is mathematically described by M partial differential equations (PDEs). Decomposition via Gauss-Jordan column reduction of the reaction network transforms M species reactive transport equations into two sets of equations: a set of thermodynamic equilibrium equations representing NE equilibrium reactions and a set of reactive transport equations of M-NE kinetic-variables involving no equilibrium reactions (a kinetic-variable is a linear combination of species). The elimination of equilibrium reactions from reactive transport equations allows robust and efficient numerical integration. The model solves the PDEs of kinetic-variables rather than individual chemical species, which reduces the number of reactive transport equations and simplifies the reaction terms in the equations. A variety of numerical methods are investigated for solving the coupled transport and reaction equations. Simulation comparisons with exact solutions were performed to verify numerical accuracy and assess the effectiveness of various numerical strategies to deal with different application circumstances. Two validation examples involving simulations of uranium transport in soil columns are presented to evaluate the ability of the model to simulate reactive transport with complex reaction networks involving both kinetic and equilibrium reactions. © 2006 Elsevier B.V. All rights reserved.

Publication Date

6-16-2007

Publication Title

Journal of Contaminant Hydrology

Volume

92

Issue

1-2

Number of Pages

10-32

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.jconhyd.2006.11.007

Socpus ID

34248384443 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/34248384443

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