Al. Walter et al., MODELING OF MULTICOMPONENT REACTIVE TRANSPORT IN GROUNDWATER .1. MODEL DEVELOPMENT AND EVALUATION, Water resources research, 30(11), 1994, pp. 3137-3148
MINTRAN is a new model for simulating transport of multiple thermodyna
mically reacting chemical substances in groundwater systems. It consis
ts of two main modules, a finite element transport module (PLUME2D), a
nd an equilibrium geochemistry module (MINTEQA2). Making use of the lo
cal equilibrium assumption, the inherent chemical nonlinearity is conf
ined to the chemical domain. This linearizes the coupling between the
physical and chemical processes and leads to a simple and efficient tw
o-step sequential solution algorithm. The advantages of the coupled mo
del include access to the comprehensive geochemical database of MINTEQ
A2 and the ability to simulate hydrogeological systems with realistic
aquifer properties and boundary conditions under complex geochemical c
onditions. The model is primarily targeted toward groundwater contamin
ation due to acidic mine tailings effluents but is potentially also ap
plicable to the full range of geochemical scenarios covered by MINTEQA
2. The model is tested with respect to ion exchange chemistry and with
respect to precipitation/dissolution chemistry involving multiple sha
rp fronts. The companion paper presents two-dimensional simulations of
heavy metal transport in an acidic mine tailings environment, focusin
g on environmental implications.