Air Date: Week of May 20, 2011

Thousands of communities struggle to keep their groundwater clean of toxics like TCE. It’s an expensive problem but, as Wynn Tucker reports, scientists have found a cheap solution - candles.

Transcript

GELLERMAN: It’s Living on Earth, I'm Bruce Gellerman. Coming up - a teenager tries a new tactic to force the government to take action on climate change: he’s suing. But first here’s Wynn Tucker with this Note on Emerging Science.

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TUCKER: Candles can be festive, somber, or useful. Now researchers have a new use for them: to clean up groundwater. Thousands of landfills and factories across the country leak toxic solvents into groundwater. One of the most common toxics is trichloroethylene, or TCE.

To clean up TCE, scientists inject the chemical compound potassium permanganate into the ground. The method is effective but expensive and labor-intensive. Researchers at the University of Nebraska have found a much cheaper solution: they’re putting potassium permanganate in candles - three-foot long wax cylinders that are then buried in the ground. As groundwater flows past these candles, the wax cylinders slowly release the chemical permanganate that breaks TCE down into harmless materials.

And the wax prevents water from entering the cylinder and keeps the chemical from dissolving all at once, evenly distributing the chemical throughout an aquifer. These candles may take a long time to work their magic, but initial results show they can effectively clean up groundwater at a low price. That’s this week’s Note on Emerging Science, I’m Wynn Tucker.

 

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