Using frozen barriers for containment of contaminants

In the summer of 2011, a full-scale test of a frozen soil barrier was deployed at the Cold Regions Research and Engineering Laboratory site in Fairbanks, AK.Hybrid thermosyphons, a more efficient cooling technology than conventional ground freezing, were used to create the frozen soil.The hybrid units were actively cooled by a 4.5 kilowatt refrigeration condensing unit for 62 days.A vertical frozen barrier of 9 meters (m) extending from a depth of 7 m below the surface to the ground surface was completed in 42 days, and the barrier was 1 m thick in 48 days.This frozen barrier installation has successfully shown that this technology can freeze the ground quickly.At the end of winter 2012, the barrier was approximately 3.8 m thick.This barrier thickness was maintained throughout the summer of 2012.The results showed only the top 0.5 m thawed even though the system was inactive for approximately a year.A cost analysis was performed to compare the cost of frozen barriers and slurry walls.It was concluded that construction and operating and maintenance costs of frozen barriers are on par with other barrier systems.