With the clatter of heavy machinery, the cleanup of the ash-laden Dan River will begin in earnest this week.
The biggest ash deposit yet found in the Dan, following a Feb. 2 spill 25 miles upriver at Duke Energy’s Dan River power plant, lies on the bottom just above Danville’s water intake.
The ash covers an area about 300 yards long and 25 yards wide. It is up to 1 foot deep. Its removal from the river will be far harder than its release into it from a broken metal pipe.
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Duke’s contractor will use a dredge that vacuums ash off the river bottom while disturbing sediment as little as possible. About 2,500 tons of ash and sediment will be sucked up by the end of June – a small fraction of the up to 39,000 tons that spilled.
The dredge was positioned in the river between two barges Monday. It sucks up ash and silt through a 6-foot opening. The material is pumped through a flexible pipeline to a machine with shaking pans that separate ash, which looks like wet cement, from water.
The material will be sent for burial in a private, lined landfill in Person County.
While river dredging is common, contractor Phillips & Jordan had previous experience with sucking up coal ash, where a primary concern is not making matters worse. The company worked to clean up the far larger 2008 ash spill by the Tennessee Valley Authority.
“We looked at several contractors, and one of the criteria was that they had to have had prior experience” with ash cleanups, said Duke official Shannon Todd.
DENR says it is still concerned for the long-term health of the Dan. The condition of animals that live on the river bottom, such as crayfish and mayflies, hasn’t been determined because of high water levels, it said.
The Environmental Protection Agency, which is overseeing the project, signed off on the cleanup method.
Nobody is publicly guessing what will happen to the rest of the ash. Duke and government officials have identified only one other ash deposit, about 40 tons upstream, that will be removed.
The flowing water has already buried some of the ash in sediment, isolating the potentially toxic metals in ash from the food chain and making it best left in place.
“The question is, does it stay buried?” said Sara Ward, a U.S. Fish and Wildlife Service ecologist. Metals can recirculate in water, in some cases, even after they have fallen to the bottom.
No dead fish or wildlife have been confirmed, Ward said. The N.C. Department of Environment and Natural Resources says high levels of aluminum and iron in the river water are naturally occurring.
“By and large, everything is normal,” said Myles Bartos, an EPA official. “We haven’t seen any exceedances that we need to respond to.”
Iron, thallium and chromium have been found in river sediment, Bartos said. Iron is often naturally occurring, and chromium showed only one high reading among some 500 samples, he said. EPA is evaluating the thallium.
Danville City Manager Joe King says Duke has been cooperative and in frequent communication since the February ash spill. But the city still expects compensation from Duke.
The city of 43,000 has filtered ash contaminants from its drinking water. Duke paid to haul 350 tons of solids from the city’s water treatment plant, tainted by ash, to a landfill.
During the river-bottom vacuuming, Danville will treat water at night to avoid contamination. The city billed Duke about $18,000 for overtime and independent water tests in February and March.
For five years, the city has also worked to fill the empty textile mills and tobacco warehouses that line its newly renamed River District. Nine miles of trails now line the Dan.
“We’re negatively impacted at a time when the city has focused its economic development on this iconic river that runs through it,” King said. “We don’t like being featured on TV news for something that impacts people wanting to locate here.”
The city announced Thursday that it has hired a Roanoke attorney to lead negotiations with Duke.
King said Danville hopes to avoid litigation but would like compensation to help improve recreation and other river-related amenities. He would not speculate on how much the city will ask Duke to pay.
Duke has said the company will pay to clean up the Dan spill, and has spent $15 million through March. It will also remove the ash left in ponds at the retired Dan River plant and some other sites.
State legislators, who convene their summer session this week, will ponder what else to require of Duke over the coming weeks.
“I want to see them assume all responsibility – and some assurance that we’re not going to be at risk,” Kay Hodges said as she walked a greenway called the Dan River Trail with her husband, Anthony. “How can we be sure this is not going to happen again?”