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: November 23, 2005

Point of Contact:
Florin Gheorghiu
Golder Associates Inc.
1951 Old Cuthbert Rd.
Cherry Hill NJ 08034 
Tel: 856-616-8166 
Email: florin@
golder.com

RCRA Site
Research Triangle Park, NC


Hydrogeology:

The bedrock is divided into a number of horizons. Each horizon includes sandstone at the base and siltstone at the top, indicating a fining upward sequence. The bedrock beds dip less than 15 degreeswith high angle fractures.

Vertical hydraulic gradients are in general downward and ground water from the overburden and upper weathered bedrock recharges deeper ground water within the bedrock. The flow is anisotropic showing higher velocities along the bedding planes and lower velocities perpendicular to the planes. Hydraulic conductivity ranges between 10-6 cm/s to 10-5 cm/s. Porosity is about 2.5%.

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

Contaminants:

Major Contaminants and Maximum Concentrations:
  • - Trichloroethene (30,000 µg/L)

Site Characterization Technologies:

  • - Pumping Tests

Remedial Technologies:

No technologies selected.

Comments:
This is a field-scale treatability pilot test using bimetallic nanoscale particles (BNP). BNP consists of nanoscale particles of zero vzlent iron with a trace coating of palladium. During the pilot test, 11 kilograms of BNP mixed in water-based slurry were injected into the shallow bedrock ground water suspected to contain DNAPL. The results of the test indicated rapid treatment of chlorinated VOCs 20 ft. to 40 ft. around the injection well. Over 90% of VOCs were destroyed within seven days.

In addition, the ORP and DO values have decreased and persisted for more than six months at very low levels indicating favorable conditions for reductive dechlorination.

Interpretation of pre- and post-test data on the in-situ microbiological community indicated changes in ORP and DO that would be expected to favor anaerobic bacteria
Remediation Goals:

This was a pilot test.


Status:

Full scale implementation may occur in the fall of 2006.

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