Effectiveness of In Situ Colloidal Activated Carbon Treatment to Mitigate PFAS Migration in Groundwater on DoD Site

Camp Grayling in Crawford County, Michigan is a training center for the Michigan Army National Guard. In 2016, the DMVA became aware of the potential contamination of PFAS from operations such as onsite firefighting training activities and began testing. PFAS was found commingled with a chlorinated solvent plume that was migrating towards the property boundary. The DMVA reviewed potential remedial options to test in the field such as pump and treat, but ultimately decided to test an in-situ reactive barrier application of colloidal activated carbon, an approach that is first of its kind in the State of Michigan.

Colloidal activated carbon was selected because of the rapid reductions of PFAS by removal from the dissolved mobile phase. Colloidal activated carbon effectively increases the retardation factor of PFAS migration contaminants by multiple orders of magnitude and eliminates the exposure to down-gradient receptors. In addition, colloidal activated carbon was selected due to its expected lower project costs when compared to operating a mechanical system.

This presentation will review the project design considerations, field activities, and post- application data. Additionally, the presentation will answer questions related to the distribution of the colloidal activated carbon in the subsurface and expected long-term efficacy.