MULTICOMPONENT GEOCHEMICAL TRANSPORT MODELING USING HYDRUS‐1D AND HP11

The transport of reactive contaminants in the subsurface is generally affected by a large number of nonlinear and often interactive physical, chemical, and biological processes. Simulating these processes requires a comprehensive reactive transport code that couples the physical processes of water flow and advective-dispersive transport with a range of biogeochemical processes. Two recently developed coupled geochemical models that are both based on the HYDRUS-1D software package for variably saturated flow and transport are summarized in this paper. One model resulted from coupling HYDRUS-1D with the UNSATCHEM module. While restricted to major ion chemistry, this program enables quantitative predictions of such problems as analyzing the effects of salinity on plant growth and the amount of water and amendments required to reclaim salt-affected soil profiles. The second model, HP1, resulted from coupling HYDRUS-1D with the PHREEQC biogeo-chemical code. The latter program accounts for a wide range of instantaneous or kinetic chemical and biological reactions, including complexation, cation exchange, surface complexation, precipitation dissolution and/or redox reactions. The versatility of HP1 is illustrated in this paper by means of two examples: the leaching of toxic trace elements and the transport of the explosive TNT and its degradation products.

[1]  R. Carsel,et al.  Developing joint probability distributions of soil water retention characteristics , 1988 .

[2]  M. Schaap,et al.  ROSETTA: a computer program for estimating soil hydraulic parameters with hierarchical pedotransfer functions , 2001 .

[3]  R. H. Brooks,et al.  Hydraulic properties of porous media , 1963 .

[4]  Paul P. Wang,et al.  MT3DMS: A Modular Three-Dimensional Multispecies Transport Model for Simulation of Advection, Dispersion, and Chemical Reactions of Contaminants in Groundwater Systems; Documentation and User's Guide , 1999 .

[5]  Günter Langergraber,et al.  Modeling Variably Saturated Water Flow and Multicomponent Reactive Transport in Constructed Wetlands , 2005 .

[6]  S. Yates,et al.  Modeling colloid attachment, straining, and exclusion in saturated porous media. , 2003, Environmental science & technology.

[7]  Jirí Šimunek,et al.  Sodic soil reclamation using multicomponent transport modeling , 1997 .

[8]  K. Kosugi.  Lognormal Distribution Model for Unsaturated Soil Hydraulic Properties , 1996 .

[9]  Judith C. Pennington,et al.  Environmental Fate and Transport Process Descriptors for Explosives , 2002 .

[10]  Jack F Schijven,et al.  Kinetic modeling of virus transport at the field scale. , 2002, Journal of contaminant hydrology.

[11]  Richard A. Karn,et al.  Distribution and Fate of Energetics on DoD Test and Training Ranges , 2004 .

[12]  Gerald L. Larsen,et al.  Fate and Transport of 17β-Estradiol in Soil-Water Systems , 2003 .

[13]  Søren Hansen,et al.  NPo-research, A10: DAISY: Soil Plant Atmosphere System Model , 1990 .

[14]  K Tirez,et al.  Aging effects on cadmium transport in undisturbed contaminated sandy soil columns. , 2001, Journal of environmental quality.

[15]  Donald L. Suarez,et al.  Two-dimensional transport model for variably saturated porous media with major ion chemistry , 1994 .

[16]  D. L. Parkhurst,et al.  User's guide to PHREEQC (Version 2)-a computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations , 1999 .

[17]  W. Durner.  Hydraulic conductivity estimation for soils with heterogeneous pore structure , 1994 .

[18]  G. T. Yeh,et al.  3DHYDROGEOCHEM: A 3-dimensional model of density-dependent subsurface flow and thermal multispecies-multicomponent hydrogeochemical transport. Final report , 1999 .

[19]  D. Marquardt.  An Algorithm for Least-Squares Estimation of Nonlinear Parameters , 1963 .

[20]  Arlen W. Harbaugh,et al.  MODFLOW-2000, The U.S. Geological Survey Modular Ground-Water Model - User Guide to Modularization Concepts and the Ground-Water Flow Process , 2000 .

[21]  F X Casey,et al.  Inverse analyses of transport of chlorinated hydrocarbons subject to sequential transformation reactions. , 2001, Journal of environmental quality.

[22]  Judith C. Pennington,et al.  Draft Protocol for Evaluating, Selecting, and Implementing Monitored Natural Attenuation at Explosives-Contaminated Sites , 1999 .

[23]  D. Mallants,et al.  Modelling uranium leaching from agricultural soils to groundwater as a criterion for comparison with complementary safety indicators , 2006 .

[24]  C. I. Steefel,et al.  New Direction in Hydrogeochemical Transport Modeling: Incorporating Multiple Kinetic and Equilibrium Reaction Pathways , 2000 .

[25]  O. Drzyzga,et al.  Microbial degradation of explosives and related compounds. , 1994, Critical reviews in microbiology.

[26]  B. Jones,et al.  WATEQ: A COMPUTER PROGRAM FOR CALCULATING CHEMICAL EQUILIBRIA OF NATURAL WATERS , 1973 .

[27]  Van Genuchten,et al.  A closed-form equation for predicting the hydraulic conductivity of unsaturated soils , 1980 .

[28]  Jirka Šimůnek,et al.  Multicomponent solute transport in soil lysimeters irrigated with waters of different quality , 2006 .

[29]  Dirk Mallants,et al.  Numerical simulation of transport and sequential biodegradation of chlorinated aliphatic hydrocarbons using CHAIN_2D , 1999 .