Cyclodextrin-Enhanced In-Situ Flushing of TCE Source Zones Resided in Heterogeneous Porous Media
DNAPLs are one of the most recognized and observed organic contaminants in groundwater. For successful
remediation effort, DNAPL source zones must be controlled or eliminated from the subsurface. The objective of this study was
to investigate the effectiveness of cyclodextrin flushing for removing source-zone DNAPL TCE for heterogeneous porous
media. 2-D tank experiments were conducted for the objectives. Although, TCE source zones in matrix and pool were
completely removed by cyclodextrin flushing, heterogeneous system exhibited an extended multi-step concentration behavior.
This non-ideal behavior was observed for both the water-flood and enhanced-flushing experiments. The results emphasized
that in the early stage, some portion of organic liquid is hydraulically accessible whereas the later stage of mass removal was
controlled by the more poorly-accessible mass associated with higher-saturation zones. Our results also showed that the
distribution and the emplacement of organic liquid, flow-field heterogeneity, flushing solution and its concentration
significantly influence on remediation effort. As a result, the performance of technology depends on the site characteristics
which are critical to characterize effective DNAPL remediation strategies for contaminated sites.
Index Terms- Cyclodextrin, DNAPL, Enhanced dissolution, Trichloroethene