The site is classified into three hydrogeological zones. Zone 1 contains an upper shallow overburden sand; Zone 2 contains a deep overburden ground water zone with sandy silty gravel to sandy gravelly silt and a weathered bedrock zone. Zone 3 is identified as containing a competent bedrock zone of ground water with the upper 60 feet made of competent bedrock.

• Fractured Bedrock

Chlorinated volatile organic compounds (CVOCs) were identified in monitoring well (MW) 03-14D and 80 feet west at MW EA-102; no contaminants were detected farther west, southwest, and north.

• Carbon tetrachloride (20,911 µg/L)
• 1,1,1,2-Tetrachloroethane (20,911 µg/L)
• Tetrachloroethene (20,911 µg/L)
• Trichloroethene (20,911 µg/L)
• 1,1,2-Trichloroethane (20,911 µg/L)

• Thermal Treatment (In Situ)
  • Steam Enhanced Extraction
• Other (Dual-phase vacuum extraction system)

Steam-enhanced remediation was used to evaluate whether the CVOCs could be remediated by steam injection and air using a dual-phase vacuum extraction system.

Several hundred pounds of CVOCs were extracted despite difficulties in introducing steam into the series of microfractures in the weathered and competent bedrock.

Pneumatic control triple well clusters screened across the three hydrogeologic zone aided in the successful introduction of steam into the fractured bedrock subsurface.

References: Osgerby, Ian T., Jim Shulz, Greg Crisp, and Ken Manchester. Chlorinated Soils Remediation Using Steam Injection Into Fractured Bedrock. Proceedings of the 22nd Annual International Conference on Soils, Sediments, and Water (Massachusetts). October 16-19, 2006.