DNAPL Dissolution in Bedrock Fractures And Fracture Networks

摘要

This project focused on measuring and evaluating the architecture, dissolution rate, and impact on groundwater quality of residually trapped tetrachloroethene (PCE) dense non-aqueous phase liquid (DNAPL) from discrete bedrock fractures and fracture networks constructed at the bench-scale. Results demonstrated that residual DNAPL in rock fractures is not well contacted by migrating water. This resulted in reduced dissolution rates, and persistence of DNAPL sources within the bedrock fractures. Bioaugmentation was effective at substantially enhancing the rate of DNAPL removal, despite dissolved PCE concentrations that were near solubility. Chemical oxidation was shown to be ineffective for treating DNAPL sources in bedrock fractures. This ineffectiveness was due to decreases in the effective DNAPL-water interfacial area (as measured using interfacial tracers) that were likely caused by oxidation reaction byproducts.