The pilot test aimed to determine if AS/SVE was a viable method to remove petroleum volatile organic compounds (PVOC) released to the subsurface soil and groundwater at the Site. The AS/SVE Pilot was submitted to the U.S. Environmental Protection Agency (EPA) for their review and approval as part of the Region V EPA’s Indian Environmental General Assistance Program (GAP).

The intrinsic permeability of the unconsolidated sand and gravel of the subsurface materials provides an ideal media for the application of vapor extraction remedial technology. As a result, vapor extraction was determined to be an ideal remedial technology for the constituents identified in the soil and groundwater at the Tower Site.

SVE involves applying a vacuum to groundwater wells and venting the extracted air/vapor mixture to the atmosphere through an organic vapor filter. The enhancement involves forcing atmospheric air into the subsurface to provide an additional volume of air for volatile organic constituent removal. The combination of AS and SVE is a common and proven technology to treat fuel hydrocarbons in soil and groundwater (U.S. Army Corps of Engineers 2013). Air sparging can also enhance the remediation capabilities of SVE in the capillary fringe zone to include less-volatile chemicals and/or chemicals that are more tightly sorbed to the soil (U.S. Army Corps of Engineers 2002).

The AS/SVE Pilot Test completed by Shannon and Wilson validated itself as a viable remediation technique for this Site. The Pilot Test demonstrated that a significant mass of gasoline fraction VOCs can be removed from soil and groundwater using SVE with AS at this site.

Project Highlights

• Shannon & Wilson validated the use and implementation of an in-situ remediation technology that is in line with the EPA’s consideration of incorporating sustainable environmental practices at remediation sites.

• AS/SVE has a much lower carbon footprint than conventional dig and dump remedial methods.

• AS/SVE minimized disruptions of land surface at the site.