Superfund Innovative Technology Evaluation (SITE)
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|IITRI Radio Frequency Heating Technology
IITRI's patented in situ RFH technology enhances the removal of volatile and semi-volatile organics by soil vapor extraction (SVE). Electromagnetic energy heats the soil resulting in increased contaminant vapor pressures and potentially higher soil permeability. RFH heats soil using rows of vertical electrodes; two outer rows bound the treatment zone while a middle row applies energy. Heating begins at the top center and proceeds downward and outward. Soils are heated to over 300°C. Extracted vapors can be treated by standard treatment technologies. RFH is most efficient in areas with low groundwater recharge. The technology was demonstrated in August 1993 at Kelly Air Force Base, Texas. Treatment effectiveness was evaluated by comparing contaminant concentrations in matched pairs of samples before and after treatment. Groundwater recharge apparently caused a short in the power electrodes, resulting in overheating of the soil near the power electrodes and diminished heating in the outer parts of the treatment zone. Within soils that reached design temperatures, statistically significant decreases in total recoverable petroleum hydrocarbons and pyrene were observed. Chlorobenze concentrations increased and several previously undetected ketones were found in treated soils.