Dominion Tweaks Coal-Ash Dewatering Process

Coal ash pond at Possum Point Power Station.

Coal ash pond at Possum Point. Photo credit: Prince William Times and Potomac Riverkeepers Network.

Dominion Virginia Power has temporarily shut down the $35 million water treatment facility at its Possum Point Power Station as it adjusts the process of cleaning water from its coal ash ponds,

Levels of selenium, a chemical element that can be toxic at high levels, rose above a “trigger” point specified in agreement between Dominion and Prince William County, reported the Prince William Times. However, Dominion was never in violation of its water quality permit, which requires the company to test treated water for selenium and a dozen other coal-ash contaminants.

Dominion officials attribute the pause in de-watering the coal ash ponds to “lessons learned” from operational challenges at Possum Point. Changes detailed in a revised engineering report, which must be approved by state and county officials, should result in discharges of selenium and zinc even lower than called for in the water permit. Also, the water-treatment facility should operate more efficiently.

“We decided to stop, redesign and update,” Jason Williams, environmental manager, told Bacon’s Rebellion. The company plans to switch from a geotube technology to clarifiers and settling tanks like the system in operation at the Bremo Power Station, he said. Also, by adding two more water-holding tanks like at Bremo, there will be less stop-and-go in the water discharge. “It will be much more efficient than firing up the system, waiting for test data, and discharging.”

Dewatering should resume early next year, pending regulatory approvals.