Subsurface barrier technologies, barrier verification, phytoremediaiton

The Department of Energy is faced with the challenging task of remediating contaminated soil throughout the complex. Subsurface barriers and surface barriers (caps) provide a means for isolation of the contaminants to inhibit further migration. Use of barriers requires estimation of system performance over time and the consequences of failure. BNL has developed technologies for In-situ Stabilization of wastes (more...), In-situ permeable barriers (more ...) and subsurface barriers (more...) including close-coupled barriers and viscous liquid barriers.

A close-coupled barrier is produced by first installing a conventional cement grout curtain followed by a thin lining of a polymer grout (more...). The resultant barrier is a cement-polymer composite that has economic benefits derived from the cement and performance benefits from the durable and resistant polymer layer.

Viscous Liquid barriers (VLBs) are another approach used for stabilization or confinement of subsurface contamination. In this technology, a viscous gel is injected in to the subsurface to either encapsulate or form a barrier around the source zone. VLBs were tested at BNL in a field demonstration (more...) and later applied to encapsulate a contamination source beneath the Brookhaven Linear Isotope Production (BLIP) facility (more...).

Barrier Verification

BNL has also been actively involved in the development and application of gas phase Perfluorocarbon Tracers (PFTs) to verify performance of subsurface barriers and covers (more...). for leak detection of subsurface barriers. Testing was performed for to determine the integrity of the VLB installed at BNL, underground ducts at the Brookhaven Graphite Research Reactor (BGRR) , and landfill caps at the Savannah River test facility (report). A white paper describing the use of PFT's for subsurface barrier verification is available (report)

In-situ Characterization

To support restoration activities, in-situ characterization of radioactivity was conducted at the Brookhaven Graphite Research Reactor (BGRR). The BGRR is being decomissioned and methods were needed for quick, accurate, reliable determinations of radioactive contamination levels of building structures. As part of an Accelerated Site Technology Deployment (ASTD) project funded by the DOE, BNL staff deployed the ISOCS (in Situ Objects Counting System) and BetaScint technologies on soils and structures in the BGRR (overview...) (presentation).

Phytoremediation

Plants are capable of extracting metals and radionuclides from soils (more) and sediments (more). Research at BNL has focused on identifying rooted plants that specifically remove contamination from the ground and understanding the mechanisms of root uptake. This knowledge is used to enhance contaminant uptake through proper plant selection, soil amendments, or genetic engineering of the plants. Studies have been conducted with Cs-137, Sr-90, and metals (Ag, Cd) on a range of plants.

Last Modified: January 31, 2008
Please forward all questions about this site to: Linda Satalino