When Duke Energy admitted to poisoning virtually all of the water wells anywhere near their ash ponds last year, lawsuits and trials and fines were filed and tried and settlements were reached. Regardless of one’s ambivalence concerning the punitive veracity of the judgements and settlements against Duke Energy for poisoning North Carolina, there is one thing we can all agree on. Those ash ponds and those potentially contaminating agents must be properly cleaned and disposed of so that no further damage is done to the surrounding environments. New research conducted at Duke University may have found a new avenue of hope in coal ash containment—air.
In a new study appearing in the April issue of Applied Geochemistry, researchers from Duke University demonstrate that the level of oxygen in a coal ash disposal site can greatly affect how much toxic selenium and arsenic can be leached from the system.
"The tests that the Environmental Protection Agency relies on consider variables like the pH of the water, but they don't look at whether the system is aerobic or anaerobic," said Heileen Hsu-Kim, the Mary Milus Yoh and Harold L. Yoh, Jr. Associate Professor of Civil and Environmental Engineering. "We wanted to demonstrate that oxygenation actually matters a lot, especially for arsenic and selenium."
Seventy percent of the coal ash waste still needs containment in North Carolina and officials and scientists are still trying to figure out exactly what to do.
One option is to essentially turn the ponds into a landfill by removing the water, capping the remaining waste with a top liner and covering it all with soil.
"Some of these ponds did not have bottom liners when they were originally constructed, so they'll be susceptible to leaking to groundwater even if they are covered on top," said Hsu-Kim, who also holds an appointment in Duke's Nicholas School of the Environment. "When you cap a site, you're separating it from air. And if the buried waste goes anaerobic, it could enhance the leaching of some elements, leading to more contamination than expected."
This new research will hopefully help in the decisions being made down the line in cleaning up the mess greed made.