North Carolina’s Department of Environmental Quality (DEQ) last week issued a permit to Duke Energy that allows excavation of coal ash stored in ponds at its Sutton Plant in Wilmington.
A DEQ press release said that a National Pollutant Discharge Elimination System (NPDES) wastewater permit is required to safely remove wet ash stored in Duke’s coal ash ponds. The Sutton facility is the first in North Carolina to receive a NPDES permit that allows for dewatering.
The DEQ press release noted that Duke’s Sutton plant is somewhat different than other coal ash sites because its coal ash impoundments do not contain “seeps,” (water emerging from the ground in the vicinity of a coal ash pond). Seeps have caused delays in obtaining federal approvals for dewatering coal ash ponds at other Duke facilities.
In addition to clearing the way for additional coal ash removal at the Sutton facility, the permit regulates treated cooling water and wastewater discharges, according to the release.
Coal ash is stored in either dry or wet form. Dry ash is stored in stacks or used as structural fill and wet ash is stored in ponds. Some coal ash ponds require the safe removal of water above the ash, otherwise known as decanting, before the excavation and removal process can begin. Impoundments that include seeps require the federal EPA to approve NPDES wastewater permits before the dewatering activities can begin.
The DEQ press release said that the state’s Coal Ash Management Act (CAMA) requires that coal ash impoundments at Duke Energy’s Sutton, Asheville, Riverbend, and Dan River facilities be permanently closed by Aug. 1, 2019. Ten remaining sites will be prioritized for closure, with all coal ash ponds and discharges from those coal ash ponds eliminated no later than 2029.