Grantee Research Project Results

Upscaling and Uncertainty of Reactive Transport in Heterogeneous and Homogeneous Porous Media

EPA Grant Number: FP916330
Title: Upscaling and Uncertainty of Reactive Transport in Heterogeneous and Homogeneous Porous Media
Investigators: Oates, Peter M.
Institution: Massachusetts Institute of Technology
EPA Project Officer: Lee, Sonja
Project Period: January 1, 2004 through December 31, 2007
Project Amount: $111,344
RFA: STAR Graduate Fellowships (2004) RFA Text | Recipients Lists
Research Category: Fellowship - Geology , Ecological Indicators/Assessment/Restoration , Academic Fellowships

Objective:

The objective of this research project is to account for unresolved-scale mixing and reaction by constructing a reactive transport model based on concentration mean and variance for heterogeneous and homogeneous porous media. Reactive transport models based on the advection dispersion equation (ADE) are inaccurate because they use spatially averaged concentrations to simulate chemical reactions. Using these averaged concentrations for reactants assumes that solutes are completely mixed (i.e., the ADE-predicted concentration is uniform at the unresolved‑scale). In reality, dispersion processes create chemical segregation and concentration distributions, and these unresolved‑scale distributions govern the amount of chemical reaction. This “concentration fluctuation model” will provide the space-time evolution of the full product and reactant distributions, and thus help cope with uncertainty.

Approach:

I will quantify how well the predicted product and reactant distributions match product and reactant distributions observed from novel laboratory-scale experiments involving clear heterogeneous and homogeneous porous media, colored dye tracers, colorimetric chemical reactions, and digital imaging.

By developing more accurate models of reactive transport, I hope to help answer important questions such as:

(1) What is the likelihood that a critical concentration will be attained at a given location?

(2) What is the likelihood that a remediation design will sufficiently reduce concentrations by a certain time?

Accurate models will help improve and design remediation schemes resulting in optimal cost and efficiency. Equally important, accurate reactive transport models will allow for the investigation and identification of governing processes and their interactions and provide a quantitative means to test conceptual models with theoretical principles and data. Use of these models to understand the factors governing solute concentrations and to optimize remediation designs will help protect safe drinking water.

Supplemental Keywords:

fellowship, groundwater, reactive transport models, upscaling, heterogeneous porous media, mixing, drinking water,, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, Waste, Fate & Transport, Geology, Ecology and Ecosystems, Environmental Monitoring, drinking water, analytical models, colorimetric chemical reactions, fate and transport, porous media, reative transport model, chemical kinetics, contaminant transport models, elementary reaction kinetics, advection dispersion equation, modeling

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.