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SUCCESSFUL APPLICATION OF AIR SPARGING TO REMEDIATE ETHYLENE DEBROMIDE (EDB) IN GROUND WATER INKANSAS
Citation:
McGuire, E. AND J. T. WILSON. SUCCESSFUL APPLICATION OF AIR SPARGING TO REMEDIATE ETHYLENE DEBROMIDE (EDB) IN GROUND WATER INKANSAS. Presented at The National Tanks Conference, Boston, MA, September 20 - 22, 2010.
Impact/Purpose:
Treating groundwater when BTEX, EDB and 1,2-DCA contaminants are present.
Description:
Although Ethylene Dibromide (EDB) was banned in conventional motor fuel in the USA by 1990, EDB continues to contaminate ground water at many old gasoline service station sites. Although EDB contamination is widespread, there is little performance data on technology to remediate EDB in ground water. Kansas DHE uses air sparging as the primary treatment technology at most of its gasoline spill sites. Air sparging is effective to treat BTEX contaminants in ground water because these compounds readily partition from gasoline to ground water and because the compounds are readily biodegraded in ground water when oxygen is available. Selden is a town in Kansas with approximately 200 people. As is the case for much of Kansas, ground water is the sole source of drinking water. In 1990 the Home Oil bulk fuel storage site in Selden was accepted into KDHE Trust Fund program. An initial site investigation showed free phase product and high levels of 1,2-DCA. EDB was first found in groundwater in 1994. In 1995, EDB was found in PWS (public water supply) #3 during routine testing. Phase I of the remedial design was installed in 1999. It included twelve SVE wells: three wells had shallow screen intervals, six wells had intermediate screened intervals and three wells had deep screened intervals. There were six air sparge wells screened 28.5 feet below static water level. Initial concentrations of benzene, 1,2-DCA and EDB in a heavily contaminated well were 2,080 μg/L, 135 μg/L, and 115 μg/L respectively. Concentrations of EDB and 1,2 DCA decreased 90+%, however the contamination in ground water was persistent. In 2007, five new, shallower air sparge wells were put online, replacing existing sparge wells. The top of screen was 12 feet versus 28.5 feet below the water table. Some new SVE wells were also installed. The new sparge wells produced a rapid decrease in concentrations of BTEX, 1,2-DCA and EDB throughout the area of influence of the remedial system. Throughout the zone of influence of AS/SVE system, concentrations of benzene, 1,2-DCA and EDB were <0.15, <0.15, and <0.0013 μg/l respectively. Air sparging can effectively treat BTEX because BTEX compounds readily partition from gasoline to groundwater and biodegrade when oxygen is available. EDB and 1,2-DCA in gasoline partition similarly to BTEX. They are also degradable when oxygen is available. With an appropriately designed SVE/air sparge system, a well defined plume and conducive lithology, EDB and 1,2-DCA can be successfully remediated along with BTEX.