Hill AFB aims to iron out pollution

HILL AIR FORCE BASE — In a "swords-into-plowshares" move, workers at Hill Air Force Base finished installing a dose of iron to the soil on the base's west side last week to combat groundwater pollution.

The iron, at one time, had been part of dummy bombs — now demilitarized — dropped by airplanes during training at the Utah Test and Training Range.

It's the first time bombs are being used to fight pollution.

The pollution treatment comes in the form of eight bore holes filled with grains of that iron. It is designed to react with trichloroethene, or TCE, a potential carcinogen that has been seeping underground since the 1940s when an oil and water separator in the rail yard used to discharge its excess water toward what is now I-15 and the city of Sunset.

At the time, people weren't aware of the ramifications of dumping industrial water on raw land, said Mark Roginske, a base project manager who oversees cleanup efforts in Sunset and Roy. The result is that a plume of groundwater stretching from the base toward Sunset and Clinton became contaminated.

The shallow groundwater isn't in local drinking water, but some of the contaminant's fumes have been found in local homes.

The prevalence of TCE, as well as other contaminants, in groundwater plumes and soil surrounding the base, landed Hill Air Force Base on the U.S. Environmental Protection Agency's National Priorities List as a Superfund site in 1987. Restoration work has been under way since 1990.

Roginske is confident that his lab tests pitting dummy bomb iron grains against TCE will be replicated in the field.

As contaminated groundwater reaches the 56-foot-deep bore holes, a reaction between TCE and iron renders the TCE inert by stripping chloride from the chemical, which was used as a degreaser on base until the 1970s.

After the final bore hole was drilled, workers dumped bucketfuls of iron grain down the shaft, a five-hour process to allow for settling.

Terry Price, a geologist with MWH, the firm that designed the bore holes, said a special sonic drill was used to keep the surrounding soil permeable.

During the next 18 months, the base's environmental employees will monitor the efficacy of the bore holes, Roginske said. If they're successful, more dummy bombs may be ground into iron grains to fill future borings across the entire plume — about 100 feet wide.

The process could be replicated at other bases dealing with similar contamination.

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