Objective:

The objective of this project is to demonstrate and validate the treatment of perchlorate in vadose zone soils through two approaches aimed at bioremediation and flushing via the infiltration of liquid electron donor.

Technology Description:

In the first approach, an engineered infiltration gallery will be designed to deliver and distribute the electron donor to the perchlorate-impacted vadose zone soils. In conjunction with the infiltration gallery, an injection well may be used to supply the donor to deeper vadose zone soils. The second approach will utilize a simple soil mixing and watering approach, where electron donor agents are mixed with the upper 2- to 3-feet of the soil column and then watered regularly, as the means of delivering electron donor agents to the contaminated vadose zone soils. Both liquid and solid donor amendments will be evaluated in the second approach. For both approaches, the most effective electron donor will be determined using site-specific column studies.

A groundwater extraction well will be installed to obtain the water used in these demonstration areas. Groundwater will be extracted and amended with electron donor and other amendments (e.g., pH buffering agents or nutrients), as necessary, for operation of each treatment area. A portion of the amended water will be directed to the infiltration gallery/injection well (if installed) and the soil mixing area, which will release the water into the vadose zone soils causing the electron donor and amendments to spread vertically throughout the vadose zone. Lysimeters and monitoring wells will be used to measure the variability and flux of perchlorate within the vadose zone and underlying saturated formation by each approach throughout the demonstration. The rate of fluid infiltration will be varied within each treatment area and the corresponding effect on contaminant mobilization and degradation rates will be monitored. Fouling control agents also may be added to the amended water to control clogging or plugging within the infiltration gallery and injection well.

Expected Benefits:

With increasing emphasis being placed on the treatment of perchlorate-impacted groundwater, cost-effective in-situ treatment strategies for perchlorate-impacted soils will become an important issue for the Department of Defense (DoD). The development of viable in-situ vadose zone treatment strategies will be particularly critical for reducing the long-term costs associated with pump-and-treat systems at sites with large depths to groundwater and high concentrations of perchlorate within vadose zone soils. (Anticipated Project Completion – 2008)

Principal Investigators:
Mr. Carey Yates
Naval Surface Warfare Center
ATTN: Code 2330I
101 Strauss Avenue, Building 863
Indian Head, MD 20640
Telephone: (301) 744-2449
Fax: (301) 744-4843
E-mail: yatesca@ih.navy.mil

Mr. Jay Diebold
Shaw Environmental and Infrastructure, Inc.
2835 North Grandview Boulevard
Pewaukee, WI 53072
Telepohne: (262) 549-6898 Ext. 424
Fax: (262) 549-6938
E-mail: jay.diebold@shawgrp.com