Innovative Mathematical Modelling in Environmental Remediation

Subsurface contamination problems of radionuclides, metals and organic co-contaminants are ubiquitous. These contaminants may exist in the solute phase or may be bound to soil particles and interstitial portions of the geologic matrix. Innovative tools to reliably predict the migration and transformation of these radionuclides, metals and co-contaminants in the subsurface environment enhance the ability of environmental scientists, engineers and decision makers to evaluate the efficacy of alternative remediation techniques and to analyse their impact prior to incurring expense in the field. A realistic mechanistically based numerical model that considers feedback between fluid flow, thermal transport and reactive transport could provide such a tool. This paper communicates the development and applications of a mechanistically coupled fluid flow, thermal transport, hydrologic transport and reactive biogeochemical model where both fast and slow reactions occur in porous and fractured media. Four example problems are employed to demonstrate how numerical experimentation can be used to evaluate the feasibility of different remediation approaches. (author)