Modeling Multispecies Reactive Transport in Ground Water

Abstract

In this paper, the details of RT3D, a general purpose, multispecies, reactive transport code, are presented. The code uses MODFLOW to simulate flow and several MT3D sub‐programs to simulate advection and dispersion. A set of reaction modules were developed and incorporated into RT3D to simulate various types of multispecies reactive transport. This new computer model can be used for analyzing different types of subsurface contaminant reactions, microbial metabolisms, and microbial transport kinetics. Details of the model and numerical solution procedure are presented. The numerical formulation of the code is general enough to allow description of any type of reaction with any number of mobile/immobile species. Several example problems are presented to test the performance of the code, and to illustrate its features. The presented numerical model is shown to be a useful tool for analyzing different types of subsurface bioremediation systems. Prediction based on this model can be used for screening remediation alternatives including natural attenuation and/or for forecasting contaminant exposure levels and environmental risks at sensitive, downgradient receptors.

Processes in Microbial Transport in the Natural Subsurface

“…In the so-called unstructured biophase approach, no structural presumption is imposed on the biophase [22,23,162,180,191] and the biomass is treated as a suspended, but kinetically sorbing/desorbing species [169,191]. Therefore, in unstructured models the biomass is a fully penetrable volumeless component which assumes that a linear relation exists between mass of substrate consumed and mass of biomass produced and that no diffusion limitations affect the transfer of substrate mass from solution into the biomass.…”

A Modular Computer Code for Simulating Reactive Multi-Species Transport in 3-Dimensional Groundwater Systems

“…As a research tool, RT3D has also been used to model several laboratory and pilot-scale active bioremediation experiments (Johnson et al 1998). The performance of RT3D has been validated by comparing the code results against various numerical and analytical solutions Sun and Clement, 1998;Sun et al 1998). The code is currently being used to model field-scale natural attenuation at multiple sites.…”

Modeling saline water intrusion in Nagapattinam coastal aquifers, Tamilnadu, India

“…Many researches focused on multi component modeling techniques for groundwater throughout the globe. The models include PHREEQC-II (Parkhurst and Appelo 1999), PHAST (Parkhurst et al 1995), HydroBioGeoChem (Yeh et al 1998), MODFLOW/MT3DMS based models such as RT3D (Clement et al 1998) and PHT3D (Prommer et al 2003). Other models developed for solute transport species include SUTRA, (Voss 1984), METROPOL (Sauter et al 1993), FEMWATER (Lin et al 1996), HST3D, (Kipp Jr 1997), NAMMU (Herbert et al 1988), FEFLOW, (Kolditz et al 1998) and MOCDENS3D, (Oude Essink GHP 2001).…”