A reaction-based paradigm to model reactive chemical transport in groundwater with general kinetic and equilibrium reactions

    Authors

    F. Zhang; G. T. Yeh; J. C. Parker; S. C. Brooks; M. N. Pace; Y. J. Kim; P. M. Jardine;D. B. Watson

    Comments

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    Abbreviated Journal Title

    J. Contam. Hydrol.

    Keywords

    groundwater quality; reactive transport modeling; equilibrium reactions; kinetic reactions; fully-implicit; predictor corrector; operator-spliffing; finite element method; Lagrangian-Eulerian approach; uranium sorption; BIOGEOCHEMICAL PROCESSES; POROUS-MEDIA; MULTICOMPONENT TRANSPORT; URANIUM(VI) ADSORPTION; HYDROTHERMAL SYSTEMS; MASS-TRANSPORT; FORMULATION; COMPONENTS; SORPTION; FLOW; Environmental Sciences; Geosciences, Multidisciplinary; Water Resources

    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 mathernatically described by M partial differential equations (PDEs). Decomposition via Gauss-Jordan column reduction of the reaction network transforms Mspecies reactive transport equations into two sets of equations: a set of thermodynamic equilibrium equations representing N(E) equilibrium reactions and a set of reactive transport equations of M-N(E) kineticvariables 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. Avariety 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. (c) 2006 Elsevier B.V. All rights reserved.

    Journal Title

    Journal of Contaminant Hydrology

    Volume

    92

    Issue/Number

    1-2

    Publication Date

    1-1-2007

    Document Type

    Article

    Language

    English

    First Page

    10

    Last Page

    32

    WOS Identifier

    WOS:000247415600002

    ISSN

    0169-7722

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