EPA 540/AR-93/509

ABSTRACT

Pneumatic Fracturing Extraction™ and Hot Gas Injection
Accutech Remedial Systems, Inc.
Applications Analysis Report
EPA 540/AR-93/509
July 1993

Accutech Remedial Systems, Inc. developed an integrated treatment system that combines Pneumatic Fracturing Extraction ™ (PFE ) with hot gas injection (HGI). The technology provides a cost effective, accelerated approach for remediating less permeable formations contaminated with halogenated volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs). The technology operates by forcing compressed gas into rock formations to open and extend existing fracture networks as well as creating new ones. This process enhances subsurface air circulation and improves contaminant mass transfer rates. Vapor extraction can be enhanced through the reinjection of heated off-gases from a CATOX vapor treatment system. The Accutech Pneumatic Fracturing Extraction process was demonstrated in August/September 1992 at an industrial site in New Jersey. The technology was evaluated in terms of airflow rate, TCE mass removal rate, and radius of influence for extraction. Hot gas injection was evaluated by injecting hot air generated by compression heating and extracting from one or more wells. The demonstration results indicated that PFE increased the extracted air flow rates by >600%. PFE also increased the rate of mass removal up to 25 times over the rates measured using conventional extraction technology. PFE also increased the effective vacuum radius of influence nearly threefold. The results of the hot gas injection experiments were inconclusive. A cost of $140/lb of TCE removed was estimated for a remediation of the demonstration site or comparable site.

Posted February 26, 1999

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