From Bench and Pilot Testing to Full-Scale Remediation of Subsurface Chromium Impacts within Multiple Media

摘要

Background/Objectives. A full-scale in situ treatment program is being implemented to remediate hexavalent chromium (Cr(VI)) impacts at a former metal plating facility located in York County, South Carolina. Chromium impacts are present in soil and groundwater in a complex hydrogeological system that consists of multiple lithological units within the overburden (saprolite) and bedrock (gneiss). In situ redox manipulation (ISRM) was selected to convert Cr(VI) to Cr(III) to reduce contaminant toxicity and mobility. Approach/Activities. The success of the program relies on a thorough and evolving understanding of the conceptual site model (CSM), including a detailed characterization of the groundwater flow regime, contaminant source areas and plume distribution and configuration. A well-formulated CSM helped in the identification of key design factors and in the development of media-specific approaches. While ISRM was selected as a common treatment process throughout the site, the remedial processes were varied among the different media in order to utilize the most optimal injection techniques and amendments for each lithological unit.