Resolving the Impact of Biological Processes on DNAPL Transport in Unsaturated Porous Media through Nuclear Magnetic Resonance Relaxation Time Measurements

Hertzog, Russel ; Geesey, Gill G. ; White, Timothy A. ; Ho, Clifford K. ; Straley, Christian ; Bryar, Traci R. ; Seymour, Joseph ; Codd, Sarah L. ; Oram, Libbie

Idaho National Engineering and Environmental Laboratory

关键词: Protons;    Solvents;    Relaxation;    Chemical Shift;    Transport;   

DOI  :  10.2172/835482
RP-ID  :  EMSP-86804-2003
RP-ID  :  835482

美国|英语

来源: UNT Digital Library

【 摘 要 】

This research leads to a better understanding of how physical and biological properties of porous media influence water and dense non-aqueous phase liquid (DNAPL) distribution under saturated and unsaturated conditions. Knowing how environmental properties affect DNAPL solvent flow in the subsurface is essential for developing models of flow and transport that are needed for designing remediation and long-term stewardship strategies. This project investigates the capability and limitations of low-field nuclear magnetic resonance (NMR) relaxation decay-rate measurements for determining environmental properties affecting DNAPL solvent flow in the subsurface. For in-situ subsurface environmental applications, lowfield proton NMR measurements are preferred to the conventional high-field techniques commonly used to obtain chemical shift data, because the low field measurements are much less degraded by the magnetic susceptibility variations between the rock grains and the pore fluid s that significantly interfere with the high-field NMR measurements. Our research scope includes determining whether DNAPLs exist in water-wet or solvent-wet environments, the pore-size distribution of the soils containing DNAPLs, and the impact of biological processes on their transport mechanisms in porous media. Knowledge of the in situ flow properties and pore distributions of organic contaminants are critical to understanding where and when these fluids will enter subsurface aquifers.