The STAR technology was applied as the primary remedy to achieve regulatory closure at a 37-acre former industrial facility in Newark, NJ. Both a surficial fill unit (ground surface to ~10 ft bgs) and an alluvial sand unit (~10-40 ft bgs), impacted with residual and free-phases of coal tar from the historic operations at the site, were remediated via smoldering combustion.
The client was facing a vexing contamination problem, and transitional remediation would have been costly and pose significant safety concerns. STAR was applied at the site using three independent treatment systems operating ‘cells’ consisting of multiple ignition points (IPs), vapor extraction wells, and interstitial thermocouples. Ignition points (i.e. standard two-inch steel wells) were installed within impacted zones and connected to an air supply to support the combustion reaction, while removable in-well 9 kilowatt (kW) heaters were deployed as the ignition source for the combustion process. Vapor extraction wells were installed within the cell to capture vapors for treatment using conventional above ground means (i.e., thermal oxidizer). Interstitial thermocouples were installed to monitor temperatures in the subsurface during operations. Cell cycle times were short (days) and following treatment the equipment was removed and reused in another treatment area at the site.
Savron/Geosyntec designed and/or procured the required equipment for the full-scale remedy as well as developed an innovative application strategy to minimize infrastructure costs associated with the 2,300 ignition events beneath the ground that are required to treat the targeted soil volume at the site. The project conservatively destroyed over 20 metric tons of coal tar in the first 5,500 cubic yards of soil.
Drilling, STAR operations, and remedy verification activities took place concurrently to accelerate the remediation process and facilitate the rapid transfer of the property to the new site owner.