The subject property was the former location of an equipment storage yard owned by a utility company. Historic operations at the property, including the operation of a manufactured gasoline plant used to distill gasoline from liquids produced during natural gas extraction, impacted approximately 12,000 cubic yards of onsite soils and adjacent stream sediments with light non-aqueous phase liquids (LNAPL). The LNAPL is highly degraded and is similar to lightweight, viscous, lubricating oil/mineral oil.
LNAPL in the onsite soils and within the stream bank and bed sediments were remediated by a two-step process: consolidation of the impacted materials followed by stabilization using an In-Situ Stabilization/solidification (ISS) treatment technology. Accomplishment of these remediation objectives also included the installation of a temporary water treatment system, a stream diversion system and construction of a barrier around the consolidated materials. Deep soil mixing was accomplished using a Delmag RH-32 (Delmag) soil mixing rig and an 8-foot diameter mixing auger. The mixing auger bit delivered the slurried reagent to the required mixing zone through pressurized nozzles in the mixing bit.
Stabilization of soils in-place greatly reduced off-site disposal costs.