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Electrically based technologies heat up the cleanup market

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September 10, 1997 Share This!

RICHLAND, Wash. — Technologies that promise faster, cheaper and more effective cleanup of certain contaminated soils now are available commercially through a new company formed jointly by Battelle and Terra Vac Corporation of Irvine, Calif.

Current Environmental Solutions LLC will bring to market two electrically based technologies -- Six-Phase Soil Heating and In Situ Corona. Six-Phase Soil Heating is a rapid, cost-effective technique that steam strips contaminants from soils in place, eliminating the need for excavation or soil pretreatment. In Situ Corona is designed to destroy toxic materials such as chlorinated solvents, PCBs, pesticides and industrial fuel oils and lubricants. The technologies were developed by Battelle researchers at Pacific Northwest National Laboratory through Department of Energy funding. Battelle operates Pacific Northwest for DOE.

CES, based in Richland, Wash., initially will focus on the deployment of Six-Phase Soil Heating as well as further development of In Situ Corona.

Six-Phase Soil Heating relies on an electrical current to heat the soil, causing moisture to boil and strip volatile and semi-volatile contaminants from soil particles. The contaminated steam is removed through venting and treated above ground.

The splitting of conventional three-phase electricity into six separate electrical phases allows for more uniform heating and larger treatment areas. Unlike conventional vapor extraction methods, CES's technique is effective in tightly bound soils, such as silts and clays, as well as saturated soils. The process not only is less expensive than many conventional technologies, but quicker, requiring weeks to remediate large sites versus months or years with other soil-venting technologies.

Whereas the soil heating technique removes contaminants for above-ground treatment, In Situ Corona is designed to destroy organic contaminants underground. Higher voltages are used to create an ionizing plasma, similar to a match flame, that destroys organic contaminants in place, or in situ. This method is effective at destroying nonvolatile contaminants such as greases, pesticides and transformer oils containing PCBs. In Situ Corona is still under development; however, Six-Phase Soil Heating has been demonstrated at several sites across the United States over the past four years.

In a field demonstration at the Savannah River Site in 1993, soil heating was used to treat more than 675 metric tons of soil contaminated with trichlorethylene and perchloroethylene, including organics suspended in a clay layer nine meters (29.5 feet) below the surface. Within 25 days, 99.7 percent of the contaminants were removed. Most recently, the technique was used to treat contaminated soil at an electronics manufacturing plant, where more than 4,990 kilograms (11,000 pounds) of perchloroethylene was removed from tight clay soil within six months. Six-Phase Soil Heating also is being developed to treat dense organic liquids in aquifers, an application that was tested successfully at Dover Air Force Base.

For more information, contact Theresa Bergsman, Current Environmental Solutions, at (509) 943-8810.

Tags: Energy

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