Upscaling and Uncertainty of Reactive Transport in Heterogeneous and Homogeneous Porous MediaEPA 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: Michaud, Jayne
Project Period: January 1, 2004 through December 31, 2007
Project Amount: $111,344
RFA: STAR Graduate Fellowships (2004) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Fellowship - Geology , Ecological Indicators/Assessment/Restoration
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.
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.