10.1021/es030029d.s001
Maria E. Malmström
Maria E.
Malmström
Georgia Destouni
Georgia
Destouni
Philippe Martinet
Philippe
Martinet
Modeling Expected Solute
Concentration in Randomly
Heterogeneous Flow Systems with
Multicomponent Reactions
American Chemical Society
2004
geochemical model PHREEQC
application
nonlinear geochemical processes
alternative solute transport modeling approaches
heterogeneity
flow fields
reaction systems
modeling solute concentrations
Model results show
mine waste deposit
Zn
acid mine drainage
reactive transport problems
handling
Randomly Heterogeneous Flow Systems
LaSAR
2004-05-01 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Modeling_Expected_Solute_Concentration_in_Randomly_Heterogeneous_Flow_Systems_with_Multicomponent_Reactions/3340951
Many environmental problems require assessment of
extensive reaction systems within natural subsurface flow
systems exhibiting large physical and biogeochemical
heterogeneity. We present an approach to couple stochastic
advective-reactive modeling of physical solute transport
(LaSAR) with the geochemical model PHREEQC for modeling
solute concentrations in systems with variable flow
velocity and multicomponent reactions. PHREEQC allows
for general and flexible quantification of a multitude of linear
and nonlinear geochemical processes, while LaSAR
efficiently handles field-scale solute spreading in stochastic
heterogeneous flow fields. The combined LaSAR−PHREEQC approach requires very modest computational
efforts, thereby allowing a large number of reactive transport
problems to be readily assessed and facilitating handling
of quantifiable uncertainty in environmental model
applications. Computational efficiency and explicit handling
of field-scale dispersion without introduction of excessive
fluid mixing that may impair model results are general
advantages of the LaSAR compared with alternative solute
transport modeling approaches. The LaSAR−PHREEQC
approach is restricted to steady or unidirectional flow fields,
and our specific application examples are limited to
homogeneous reaction systems without local or transverse
dispersion-diffusion, although these are not general
methodological limitations. As a comprehensive application
example, we simulate the spreading of acid mine drainage
in a groundwater focusing on Zn<sup>2+</sup> and including relevant,
major-component geochemistry. Model results show that
Zn<sup>2+</sup> may be substantially attenuated by both sorption and
precipitation, with flow heterogeneity greatly affecting
expected solute concentrations downstream of the mine
waste deposit in both cases.