Grantee Research Project Results
2002 Progress Report: The Effect of Clay on DNAPL Behavior During Alcohol Flushing
EPA Grant Number: R827120Title: The Effect of Clay on DNAPL Behavior During Alcohol Flushing
Investigators: Hayden, Nancy J.
Institution: University of Vermont
EPA Project Officer: Aja, Hayley
Project Period: December 1, 1998 through November 11, 2001 (Extended to June 21, 2003)
Project Period Covered by this Report: December 1, 2001 through November 11, 2002
Project Amount: $375,240
RFA: Exploratory Research - Environmental Engineering (1998) RFA Text | Recipients Lists
Research Category: Safer Chemicals , Land and Waste Management , Sustainable and Healthy Communities
Objective:
The overall objective of this research project is to investigate the effect of clay and clay colloids on the distribution of dense non-aqueous phase liquids (DNAPLs) in porous media, and the subsequent effect on DNAPL distribution, mass transfer, and interfacial phenomena during alcohol flushing. An improved understanding of DNAPL behavior is critical for improving restoration attempts using in situ methods such as alcohol flushing.
We have performed a series of experiments and analyses at the pore and column scales to meet the project objectives. We used kaolinite and Ca-montmorillonite clays for the majority of experiments. Isopropyl alcohol (IPA) and tetrachloroethylene (PCE) have been used as the alcohol and DNAPL respectively. We completed most of the batch and column studies during Year 3 of this research project; however, we completed some final pore-scale studies and additional pore-scale modeling in Year 4.
Progress Summary:
During Year 4, we finished the laboratory research and analyzed the data, numerically modeled pore-scale processes, and wrote journal articles. The micromodel technique has been modified to provide some quantitative data including permeability, pore entry pressures, and DNAPL saturation. Measuring permeability was not valid in the micromodels because the needles dominated flow in the sand and kaolinite sand systems. However, pore entry pressures reasonably matched with column data.
We have presented most of the results in previous progress reports with modifications. Filling in data gaps resulted in the most laboratory results this past year. We used micromodels to observe pore-scale phenomena in sandy porous media with and without clay, and methods and preliminary results have been described in previous reports. Quantifying permeability, pore entry pressures, and saturation has been the focus during the past several months. Additional micromodels have examined different clay contents.
We quantitatively analyzed the pore-scale spatial distribution of two immiscible fluid phases in clay containing media according to the ideal soil model. This also has been explained in the Year 3 progress report, but we completed additional work to the model to increase its value in pore-scale modeling.
We are ensuring precision and accuracy criteria, representativeness, completeness, and comparability criteria by taking multiple samples from the same batch or column samples where applicable. We also are performing replicates within a treatment and replicate analyses, establishing well-characterized and consistent initial and ongoing conditions with batch and column experiments, and performing statistical analyses on the results.
We use daily calibration curves for gas chromatography/flame ionization detector (GC/FID) analysis and other analytical instrumentation. For GC analysis, typically we run a 5-8 point calibration curve from multiple stocks. We also run check standards after every 10 samples.
We made modifications to the micromodel procedure and the pore-scale modeling that should allow for more quantitative applications of these new methods. A no-cost extension has been granted to complete some additional papers, modeling, and writing the final report.
Future Activities:
We will complete the revisions on the two submitted papers; both required some additional laboratory results, which have been completed. In addition, two more papers are in progress and will be submitted. These also may require some additional laboratory and modeling work.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
| Other project views: | All 8 publications | 2 publications in selected types | All 2 journal articles |
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Matmon D, Hayden NJ. Pore space analysis of NAPL distribution in sand-clay media. Advances in Water Resources 2003;26(7):773-785. |
R827120 (2001) R827120 (2002) R827120 (Final) |
not available |
Supplemental Keywords:
cosolvent flushing, soil colloids, chemical mixtures, dense non-aqueous phase liquid, DNAPL, alcohol flushing, clay, electrophoretic studies, hazardous chemicals, hazardous waste treatment, infrared spectroscopy sensor, interfacial phenomena, mass transfer, restoration., RFA, Air, Scientific Discipline, Waste, Toxics, Hazardous, Remediation, Engineering, chemical mixtures, Electron Microscopy, HAPS, Environmental Chemistry, Engineering, Chemistry, & Physics, Hazardous Waste, clay, electrophoretic studies, infrared spectroscopy sensor, alcohol flushing, hazardous waste treatment, interfacial phenomena, soil colloids, DNAPL, mass transfer, restorationProgress and Final Reports:
Original AbstractThe 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.