Integrated Hydrothermal Characterization of DNAPL Source Zones and Subsurface Heterogeneity for Enhancing DNAPL Thermal Remediation Prediction

Abstract

Developing efficient and cost-effective in-situ thermal treatment (ISTT) strategies for the treatment of dense nonaqueous phase liquid (DNAPL) requires detailed characterization of subsurface heterogeneity and DNAPL source zone architecture (SZA). However, current characterization methods are costly and often provide limited information about the aquifer and DNAPL SZA. In this study, a data fusion framework is developed to interpret the site-specific observation from DNAPL-contaminated zones treated with ISTTs. Cross-correlation analysis reveals that observed temperature, pressure, and extracted flow rates during ISTTs provide the most significant information about aquifer permeability (lnk) distribution and source/sink conditions. Using numerical experiments, we demonstrate the effectiveness of the proposed inversion framework, and integrating temperature, pressure, and pretreatment contaminant concentration data for inversion leads to the best characterization. Results also show that uncertainty in the variance of lnk and source/sink conditions has a minor influence on the estimates.