Case Studies - CA002 - Pneumatic Fracturing, SVE

Industrial Facility, - Northwestern California

Project Summary

Pneumatic fracturing was applied at a rail yard site located adjacent a 150-year old historical building in Northern California where contaminants, such as VOCs, polynuclear aromatic hydrocarbons, and metals, have been detected in the soil and ground water. The contamination stemmed from historic onsite activities. To address the presence of VOCs in the subsurface, a SVE/CatOx system was installed. Although a significant amount of VOCs had been removed from the upper sand layer, the presence of VOCs was still detected in the clay layer. As a result, Pneumatic Fracturing was applied in order to increase the permeability in the clay zone.

Procedure

The process required the application of Pneumatic Fracturing to address a discrete clay layer (16 ft to 20 ft bgs) within the formation. The unique challenge of this project was the application of the technology without damaging the historical building.

Outcome

After pneumatic fracturing, concentrations in the extraction gas increased significantly and vacuum influence was extended to wells previously not influenced. The fracturing activities did not impact the structural integrity of the historic building only 20 feet from the injection points.


Left: ARS surveying pre-existing cracks, blemishes on building before injection.   Right: The white chalk marks show grid system usd in documentation pre-existing condition of structure.

 

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