U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Fractured Bedrock Project Profiles

Last Updated: July 26, 2006

Point of Contact:
Tess Rottero
10239 Technology Drive
Knoxville TN United States 37932 
Tel: 865-671-6774 
Fax: 865-671-6254
Email: te.rottero@

U.S. Army Rainbow Elementary School
Ansbach, Germany


The site is underlain by a fractured sandstone aquifer.

Targeted Environmental Media:
  • - Dense Non-aqueous Phase Liquids (DNAPLs)
  • - Fractured Bedrock


Contaminant concentrations indicated the presence of residual free-phase chlorinated hydrocarbon (CHC) product at the base of the aquifer beneath the building.

Site Characterization Technologies:

No technologies selected.

Remedial Technologies:

  • - Bioremediation (In Situ)
    • Reductive Dechlorination (In Situ Bioremediation)
Three injection wells were installed as part of a pilot test and Hydrogen Release Compound (HRC) was injected to enhance anaerobic biological in situ cometabolic reduction of contaminants. Contaminant concentrations, by-products, and other parameters of concern were monitored over a 6-month period.
Remediation Goals:

This pilot test was conducted to evaluate the feasibility of enhanced biodegradation for this site.


As a result of the HRC injection, a CHC mass reduction of 62 to 73 percent was achieved within 4 months. After 6 months, concentrations of CHCs within the treated area had decreased to less than 1 percent of the initial levels.

Lessons Learned:

The change in the CHC ratio suggests that the main biodegradation mode may have changed from cometabolic reduction to dehalorespiration.

Rottero, Tess; Craig Walmsley; Oliver Kohnen. 2004. Evaluating Innovative Bioremediation Technologies and Successful Pilot Test Performance. The Fourth International Conference on Remediation of Chlorinated and Recalcitrant Compounds, Monterey, California, May 24-27.

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