Utah Water Science Center
Long-term monitoring, performance evaluation, and on-site stabilization of three permeable reactive barriers (PRBs)
operating at a remote abandoned mine tailings site
Project Number: 9716BAF01
Cooperating Agency: Bureau of Land Management
Project Chief: David Naftz, USGS Salt Lake City, Utah
Project Period: 1998-2005
Placement of reactive material into a gate structure of the bone-char phosphate barrier at Fry Canyon, Utah
|
Problem: Abandoned uranium upgrader operations at Fry Canyon, Utah,
on Federal land managed by the Bureau of Land Management (BLM), contain contaminated shallow ground water in the colluvial
aquifer. This aquifer is contaminated with elevated concentrations of uranium (U) that can exceed 20,000 micrograms per
liter ( m g/L). Cleanup of this contamination, especially at remote sites, can be costly and difficult.
Permeable reactive barriers (PRBs) have been proposed to assist the BLM in cleanup efforts. Permeable reactive barriers
(PRBs) are potentially cost-effective alternative technology to pump-and-treat methods. A PRB is a permanent,
semi-permanent, or replaceable unit that is installed across the flow path of a contaminant plume. A PRB contains a zone
of reactive material that acts as a passive in-situ treatment zone. This in-situ treatment zone immobilizes contaminants,
such as radionuclides and other trace elements, as ground water flows through it. Operational and maintenance costs are
lower because water flow across the PRBs is driven by the natural gradient and the treatment system does not require power,
making them ideally suited for remote site applications. Reactions within the PRB material either degrade contaminants
to non-toxic forms or transfer the contaminants to an immobile phase. Potential limitations to PRBs include re-release of
contaminants after aging of reactive material, cost effective removal or in-situ stabilization of the reactive material
after breakthrough, and deleterious effects of barrier material on downgradient water quality. |
Objectives: The objectives of this study are to: (1) continue the operation of the three PRBs at the Fry
Canyon site through September 2005; (2) assess chemical and physical processes controlling PRB performance as the PRBs
continue to age; (3) develop and test a cost-effective procedure for on-site stabilization of PRBs in remote areas; and
(4) monitor the performance of on-site PRB stabilization.
Relevance and Benefits: The study will provide critical information to the BLM concerning the future
management and oversight of the abandoned waste at the Fry Canyon site. Depending on the utility and longevity of the PRB
installation at the site, substantial saving could be realized in the remediation of the waste relative to complete removal
and storage. Results of this study can be transferred to other sites with similar contamination.
Approach: The performance of the PRBs will be evaluated with three different, but related activities:
(1) bi-annual water-quality and microbiological monitoring of each PRB; (2) annual tracer tests and periodic water-level
monitoring to determine changes in the hydrologic properties of the PRBs; and (3) solid-phase sampling of the PRBs.
Products: Recent reports related to activites at the Fry Canyon site are:
Rowland, R.C., 2002, Sulfate-reducing bacteria in the zero valent iron permeable reactive barrier at
Fry Canyon, Utah, in Naftz, D.L., Morrison, S.J., Davis, J.A., and Fuller, C.C. eds., Handbook of Groundwater
Remediation Using Permeable Reactive Barriers: Applications to Radionuclides, Trace Metals, and Nutrients, Academic Press,
New York, New York, p. 282-305.
Fuller, C.C., Piana, M., Bargar, J.R., Davis, J.A., and Kohler, M., 2002, Evaluation of apatite materials for use in permeable
reactive barriers for the remediation of uranium-contaminated groundwater, in Naftz, D.L., Morrison, S.J., Davis, J.A., and
Fuller, C.C. eds., Handbook of Groundwater Remediation Using Permeable Reactive Barriers: Applications to Radionuclides, Trace
Metals, and Nutrients, Academic Press, New York, New York, p. 256-281.
Fuller, C.C., Bargar, J.R., Davis, J.A., and Piana , M., 2002, Mechanisms of uranium interactions with hydroxyapatite:
Implications for groundwater remediation: Environ. Sci. Technol., v. 36, p. 158-165.
Fuller, C.C., Bargar, J.R., Davis, J.A., and Piana, M., in press, Mechanisms of uranium interactions with apatite: Evaluation
of sorption by bone meal and bone charcoal: Environ. Sci. Technol.
Back to Utah WSC home page
