Innovative mathematical modeling in environmental remediation.

Area of Science:

• Environmental Science
• Geochemistry
• Hydrogeology

Background:

• Reactive transport modeling is crucial for understanding contaminant behavior in subsurface environments.
• Traditional ad hoc models (e.g., Kd simplification) have limitations compared to mechanistic approaches.
• Mechanistic models offer deeper insights into biogeochemical processes governing contaminant transport.

Purpose of the Study:

• To review the development of a coupled reactive transport model.
• To demonstrate the application of this model to environmental remediation challenges.
• To evaluate the feasibility of different remediation strategies through numerical experimentation.

Main Methods:

• Development of a mechanistically coupled model integrating fluid flow, thermal transport, hydrologic transport, and reactive biogeochemistry.
• Application of the parallel model version to a uranium tailing problem at Oak Ridge National Laboratory.
• Simulation of laboratory-scale and field-scale experiments involving various contaminants and remediation techniques.

Main Results:

• The model successfully simulated uranium mobilization and the inadequacy of simplified Kd models.
• Demonstrated the potential of microbially-mediated immobilization of uranium using acetate amendment.
• Evaluated complex scenarios with high concentrations of radioactive elements and toxic metals.

Conclusions:

• Mechanistic reactive transport models are essential for accurate environmental remediation protocols.
• Numerical experimentation with these models can effectively assess remediation strategy feasibility.
• The developed model provides a robust framework for simulating contaminant fate and transport.