Hydrogeophysical imaging of deposit heterogeneity and groundwater chemistry changes during DNAPL source zone bioremediation.

摘要: Robust characterization and monitoring of dense nonaqueous phase liquid (DNAPL) source zones is essential for designing effective remediation strategies, assessing the efficacy treatment. In this study high-resolution cross-hole electrical resistivity tomography (ERT) was evaluated as a means field-scale in-situ bioremediation experiment, in which emulsified vegetable oil (EVO) electron donor injected into trichloroethene zone. Baseline ERT scans delineated geometry interface between contaminated alluvial aquifer underlying mudstone bedrock, also extent drilling-induced physical heterogeneity. Time-lapse images revealed major preferential flow pathways plume zones, were corroborated by multiple lines evidence, including geochemical hydraulic testing using high density multilevel sampler arrays within geophysical imaging planes. These shown to control spatial distribution EVO, bicarbonate buffer introduced cell pH control. Resistivity signatures observed that consistent with elevated chloride levels, providing tentative evidence from biodegradation chlorinated solvents.