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Steam technology used to clean Calif. Superfund site

Sunday, November 22, 2009

Dynamic Underground Stripping sounds like something you would find in an after-hours club South of Market, but it's a new technology for steam cleaning the Earth. Just weeks ago, in Visalia, it was used in the first complete cleanup of a Superfund site.

Nearly every wooden utility pole is protected from dry rot and insects because it is soaked in creosote, dark, smelly coal tar. Places where that soaking was done have been declared Superfund sites by the Environmental Protection Agency.

One such site in Visalia was the first to be removed from the list thanks to steam cleaning, a technique first used to remove a decades-old gasoline spill by the Navy at Lawrence Livermore National Laboratory.

In 1992, Lab geophysicist Roger Aines stood on the spot and declared, "We're installing a ring of six wells around that spill in order to inject steam and herd the spill in toward central extraction wells from which we'll then pump the gasoline, and eventually pump the steam, out of those central extraction wells."

It worked.

Years later, Aines returned to that site with ABC7 to describe a new technology Lawrence Livermore has added. They are exploiting steam-loving microbes to kill half of the bad stuff while it is still underground. That is what helped clean up Southern California Edison's Visalia Pole Yard.

The power company went from extracting one pound per week to 11 tons per week. Instead of taking 200 years using old techniques, it took just 10 years. Instead of costing $100 million, it cost $14 million.

"Things that are above the water table, often, you end up digging them up," says Aines. "And, that works fine. But if it's below the water table, below the standing water in the soil, it's very hard to dig them up. And, so, this proves to be a very efficient way to get those out."

The lab is confident that the technique could accelerate Superfund remediation by hundreds of years.

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