By Deon Roberts, deroberts@charlotteobserver.com

ASHEVILLE – The trucks carrying toxic coal ash began rumbling past Woodrow Mack’s Asheville-area home about three years ago.

The trucks, hauling loads of the material to Asheville Regional Airport, were a constant racket.

“All damn day long, until about 5, 6 o’clock in the night,” Mack said.

Charlotte officials are considering burying coal ash at Charlotte Douglas International Airport. In Asheville, the sight and sounds of ash-filled trucks passing by have become a normal part of life.

Since 2008, the Asheville airport has been receiving the ash from Charlotte-based Duke Energy. Duke gives the airport the ash for free, and the airport uses it as fill material for construction projects.

Duke and Charah, the Louisville, Ky., project manager for the Asheville project, are seeking a deal for a similar project involving Charlotte’s airport. Charah specializes in handling coal ash, the left-over byproduct of burning coal to create electricity.

Duke wants to move about 4 million tons of coal ash from the retired Riverbend Steam Station, to Charlotte Douglas. Despite expressing some skepticism about the plan, Charlotte City Council members decided Monday to study the proposal. No council members objected.

What Charlotte can expect

On Thursday, in a tour of the Asheville airport for the media, Duke and Charah officials gave an up-close look at what might go on at Charlotte Douglas if the idea gets the go ahead. Scott Sewell, Charah’s chief operating officer, said the Charlotte project would be “very similar” to the Asheville operation.

The ash being used at the Asheville airport comes from a power plant at Lake Julian, where the slurry is poured into the back of trucks and covered with a tarp. The truck’s wheels are cleaned of coal ash, and then they are sent to the airport.

Sewell said 15 to 20 trucks are used to carry the ash to the airport about 2 miles away up to 200 times a day.

Duke officials said the trucks do not haul on weekends and holidays to minimize traffic.

At the airport, the ash is put down in layers, one foot at a time. Plastic and other synthetics make up the four layers of materials used to encapsulate the ash.

The ash goes over three layers of synthetic materials, then a liner is put on the ash, followed by a 6-foot layer of dirt. Environmentalists have described the process as being similar to creating a big ash burrito.

Sewell touted the durability of the materials, which are meant to contain the ash. The materials can last for hundreds of years, he said.

“We’re using the best materials and methods known to man today,” he said.

Any water draining from the site makes its way into the local sewage system and then to the wastewater treatment facility, he said.

Airport, Duke call it a win/win

So far, about 3 million tons of ash have been brought to the Asheville airport.

Environmentalists have said that when authorities started the first phase of the fill project, Duke and Charah used a flimsy liner; the riverkeeper for the French Broad River said his group documented coal ash flowing downstream to a nearby neighborhood that used well water.

Environmentalists have since said the project seems a decent solution, at least for the short term.

On Thursday, a deep pit on the west side of the airport was filled with the dark-gray ash as work continues on what will become a new taxi field. The airport also plans to use the ash to help reconstruct its main runway, a project airport officials say is set for completion in 2017.

Duke and Asheville airport officials called the coal-ash project a success. Airport spokeswoman Tina Kinsey said there have been no environmental concerns about the ash thus far.

“It’s a very regulated process,” she said.

The Asheville airport estimates it will save at least $12 million by using the ash, instead of buying its own fill.

Sewell said coal ash is superior to other fill materials because it packs very well.

“Better than dirt or any other material that we’ve used,” Sewell said.

Cautiously optimistic

Environmentalists have been cautiously optimistic about the plan to move Duke’s ash to Charlotte Douglas. The head of the Catawba Riverkeeper Foundation said earlier this week that almost any plan would be preferable to leaving the coal ash in unlined pits next to the city’s water reservoir.

Charlotte Douglas could save $30 million it might otherwise spend on fill dirt for construction projects, according to city documents. But Charlotte Douglas officials haven’t identified any specific projects they could use the ash for yet.

The coal ash at Riverbend is currently in unlined storage ponds sitting on the banks of Mountain Island Lake, Charlotte’s source of drinking water. Environmentalists worry about the effects of toxic heavy metals, such as lead and arsenic, that can leach from coal ash into the water.

Duke decided to close its ash ponds at Riverbend following a Feb. 2 spill at another power station on the Dan River that released thousands of tons of ash into the river.

Sewell said officials are using a 60-day due diligence period to analyze the coal ash project at Charlotte Douglas.

It’s also unclear how the ash will be transported to Charlotte Douglas in the roughly 15-mile journey from the Riverbend site. Sewell said trucks are one option – rail is another.

If trucks are used, they would travel on major highways, not residential roadways, he said.

Charah handles about 16 million tons of ash a year in 18 states, he said. The company has hauled ash as far as 90 miles in other states, he said.

“We are ash experts, for lack of a better term,” Sewell said.

Charah is a family-owned company. Chief executive Charles Price told the Charlotte City Council this week that he and his wife co-founded the firm in 1987, naming it for their children Charles and Sarah.

Coal ash has been used as fill material in construction projects for decades, largely without regulation. Charah has said the Asheville project exceeds applicable regulations by using a fully-sealed liner to wrap the ash and a system to collect contaminated water that leaches from the site. Charlotte Douglas would feature similar safeguards.

Mack, the Asheville-area resident who lives near a coal-ash fill site, said he’s not worried about the impact the coal ash might have on his health. But he said other residents closer to Lake Julian have complained about ash coating their property.

“They’ve said it would get all over their house, their porches and everything else.”

He’s just relieved that the truck routes have shifted further from his property.

“Hell, yeah,” he said. “That went on about two or three years.”

Staff writer Ely Portillo contributed.