HYDROGEOCHEM: A coupled model of HYDROlogic transport and GEOCHEMical equilibria in reactive multicomponent systems
This report presents the development of a hydrogeochemical transport model for multicomponent systems. The model is designed for applications to proper hydrological setting, accommodation of complete suite of geochemical equilibrium processes, easy extension to deal with chemical kinetics, and least constraints of computer resources. The hydrological environment to which the model can be applied is the heterogeneous, anisotropic, saturated-unsaturated subsurface media under either transient or steady state flow conditions. The geochemical equilibrium processes included in the model are aqueous complexation, adsorption-desorption, ion exchange, precipitation-dissolution, redox, and acid-base reactions. To achieve the inclusion of the full complement of these geochemical processes, total analytical concentrations of all chemical components are chosen as the primary dependent variables in the hydrological transport equations. Attendant benefits of this choice are to make the extension of the model to deal with kinetics of adsorption-desorption, ion exchange, precipitation-dissolution, and redox relatively easy. To make the negative concentrations during the iteration between the hydrological transport and geochemical equilibrium least likely, an implicit form of transport equations are proposed. To alleviate severe constraints of computer resources in terms of central processing unit (CPU) time and CPU memory, various optional numerical schemes are incorporated in the model. The model consists of a hydrological transport module and geochemical equilibrium module. Both modules were thoroughly tested in code consistency and were found to yield plausible results. The model is verified with ten examples. 79 refs., 21 figs., 17 tabs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- Sponsoring Organization:
- DOE/EH
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6230985
- Report Number(s):
- ORNL-6371; ON: DE91007825
- Country of Publication:
- United States
- Language:
- English
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540320* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (1990-)
58 GEOSCIENCES
580000 -- Geosciences
CHEMICAL PROPERTIES
CHEMICAL REACTIONS
CHEMISTRY
COMPUTER CODES
COMPUTERIZED SIMULATION
DATA BASE MANAGEMENT
DISSOLUTION
ENVIRONMENTAL TRANSPORT
FLUID FLOW
GEOCHEMISTRY
H CODES
HAZARDOUS MATERIALS
HYDROLOGY
ION EXCHANGE
MANAGEMENT
MASS TRANSFER
MATERIALS
POLLUTION
PRECIPITATION
REDOX REACTIONS
SEPARATION PROCESSES
SIMULATION
SORPTION
STEADY FLOW
SUBSURFACE ENVIRONMENTS