In-situ Vitrification Tested at Chemical Pits
Waste pits referred to as the Chemical/Animal Pits and Glass Holes were located in the southeast portion of the BNL site near the Former Landfill used by both the U.S. Army and BNL. The Pits were used by BNL from 1950s to 1966 for the disposal of chemical containers, glassware, and animal carcasses containing radioactive tracers. The Glass Holes were used from 1966 to 1981 for the disposal of laboratory glassware and containers. The Pits varied in size from 10 to 20 feet wide and from 12 to 30 feet deep. Both soil and groundwater contamination was found in the area. Contaminants of concern included volatile organic compounds (VOCs) and the radionuclide Strontium-90.
Prior to cleaning up the Pits, under Operable Unit I, Area of Concern (AOCs) 2B and 2C, BNL explored several alternatives. An emerging new technology referred to as "in-situ vitrification" was one of the alternatives considered. Electricity was used to melt the waste and surrounding soil in place. It was then cooled to form glass. The expectation was that contaminants not destroyed by the heat would be encapsulated within the glass so that they could not leach into the soil or groundwater.
A pilot study utilizing the technology was conducted on a simulated waste pit in June 1996. The study raised concerns that the method would not capture or destroy all the organic contaminants and would rupture sealed containers during the process; therefore it was not selected as the cleanup remedy.
The Chemical/Animal Pits and Glass Holes would later be excavated and the material sent offsite for disposal. The VOC groundwater plume was found to have traveled off-site and is being remediated by groundwater treatment systems both at the BNL site boundary and off-site. Because radionuclides readily bind to the soil and therefore move at a very slow rate, the Sr-90 plume did not reach the BNL site boundary. The plume is expected to undergo active treatment until 2014 and will then be monitored until 2030.
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