Using Candles To Clean Up Groundwater

April 1, 2011— -- An experiment underway in a small Nebraska town may hold the answer to a common problem associated with industry -- groundwater contamination.

If the results are as successful as preliminary reports indicate, then researchers will have found a vastly cheaper and easier method that could then be applied to a wider range of contaminates found in the nation's water supply.

"We're always looking for new, better ways to handle the contamination and obviously the cheaper the better, as long as it can be effectively and safely done," said Ken Rapplean a project manager at the U.S. Environmental Protection Agency (EPA).

An estimated 15,000 sites across the country leach toxic chlorinated solvents into groundwater -- anywhere an old landfill, dry cleaning facility or military installation might be found. Among the most common is a solvent typically used as a degreaser and metal parts cleaner, trichloroethylene or TCE.

"Chlorinated solvents like TCE are quite common in any kind of industrialized area," said Laurie Brunner, a groundwater geologist with the Nebraska Department of Environmental Quality. "It's an unfortunate byproduct of industry."

Even places like Cozad -- a small town of 4,000 in central Nebraska -- have enough industry for TCE contamination. What it doesn't have are the millions of dollars it might take to clean up the mess -- particularly now that the town's largest employer will close its doors in June.

But researchers from the University of Nebraska-Lincoln stepped in with an interesting idea.

They sunk more than 150 chemically treated wax cylinders -- each about three feet long and three- to two-inches wide -- into 31 locations, and then walked away. After 85 days, the water at one sample site showed significant improvement, dropping from about 400 parts per billion to just over 70. The EPA lists the minimum acceptable contamination level for TCE at just 5 ppb.

A common treatment for TCE-contaminated water and soil is to introduce a much safer compound, potassium permanganate. On contact, permanganate breaks down TCE -- a suspected carcinogen -- into harmless materials like carbon dioxide and chlorine.