Due to the multiple structures, close proximity to a state highway, and impediments on the relatively small Site, a traditional excavation was not plausible. GSI proposed removing a large portion of the impacted soil with a nontraditional approach of large diameter boreholes.  These boreholes were five feet in diameter and extended to 45 feet below ground surface (bgs). A total of 19 boreholes were completed, removing a total of 636 yards of soil. The boreholes were backfilled with sand to approximately six feet bgs and then clean native soil was used as backfill to the surface.

The next phase of remediation at this Site was to install free product wells, air sparge wells, and soil vapor extraction wells. GSI will complete the construction phase of the project by installing piping for a soil vapor extraction and air sparge remediation trailer.  This system will address the contamination present in groundwater that could not be treated with the excavation.

Ultimately the excavation by large diameter borehole removed the majority of the source of contamination. This and the remediation system will greatly decrease the time, costs, and samples needed to monitor the extent of the groundwater plume.