SUPERFUND SITE: MISSOURI ELECTRIC CLEANUP TO SERVE AS DEMONSTRATION

At first glance, it looks like a normal construction site.

But behind the green hardhats and plastic safety glasses and beyond a fenced-off area, the work of cleaning up one of the nation's Superfund sites is under way.

TerraTherm, an environmental firm based in Houston, Texas, is handling a test cleanup of PCB-contaminated soil at the Missouri Electric Works site in Cape Girardeau.

The firm is doing the demonstration project in an effort to convince the Environmental Protection Agency that its cleanup technology will work as well as the more conventional practice of excavating and incinerating contaminated soil.

If the demonstration goes well, the firm could get a green light to bid on the overall cleanup project.

But a full-scale cleanup could be two years away. The task is mired in regulatory paperwork and court proceedings.

In the meantime, TerraTherm has moved ahead with the small-scale cleanup effort.

Behind two trailers and the fenced-off area at Missouri Electric Works' site at 824 S. Kingshighway, a thermal blanket is heating contaminated surface soil. "We have been running the blanket for about a week," said Jim Steed, project manager.

The 8-by-20-foot thermal blanket heats the surface soil to about 1,200 degrees Fahrenheit.

The blanket of heat coils are laid on top of the ground. A pipe extends from the blanket to a vacuum extraction device that pulls out, cooks and filters any remaining vapors so that only carbon dioxide and water vapor are released into the atmosphere.

Another section of ground will be heated by a dozen thermal wells placed in sort of a diamond shape.

Steed said he hopes to have the wells running within two weeks. The wells will treat an area 400 square feet in size and extend 12 feet beneath the surface.

"Actually there is not any contamination below 8 or 9 feet," he said.

The company plans to operate the thermal wells for about a month. The soil is heated to about 1,200 to 1,400 degrees Fahrenheit at the wells. But farther away from the wells, temperatures will reach 400 degrees.

That is still hot enough to destroy polychlorinated biphenyls or PCBs, Steed said.

As the heat from the wells vaporizes soil contaminants, a vacuum applied to each well draws the vapors out of the ground. The same vapor treatment system is used with both thermal wells and blankets.

TerraTherm has about a dozen workers at the 6.4-acre site. The demonstration project operates around the clock.

Steed said the work should be completed by the end of April. After that it would take another 30 days to retest the soil and issue a report.

The EPA has made several visits to the site to monitor the cleanup work, Steed said.

TerraTherm began setting up the trailers and equipment at the site about a month ago. Recent rains saturated the ground and slowed the demonstration project, Steed said. When the soil is wet, he said, it takes longer to heat up the soil.

The contamination problem was discovered 12 years ago. Some areas at the site were found to have PCBs in concentrations of 21,000 parts per million.

The site has been on the federal Superfund priority list for six years.

The EPA has estimated it could cost $17 million to clean up the site. The cost for a full-scale cleanup will be borne largely by potential responsible parties, cities and businesses that took electrical transformers to Missouri Electric Works for disposal, repair and storage.

The federal government will pay some of the cost.