The Metropolitan Sewerage District of Buncombe County announced Dec. 28 that 374,000 gallons of sewage had spilled into the French Broad River over the course of 21 hours on Dec. 25. Maintenance Division Director Ken Stines said the spill was caused by a power outage after high winds knocked out a transformer at 2 a.m. on Christmas Day.
Excessive storm water due to snow melt increased the volume of the spill, he noted. MSD officially classified the cause as a "severe natural condition."
At 2:45 a.m., workers at MSD's Woodfin plant on Riverside Drive spotted sewage flowing from a manhole at the river's edge. Although power was restored to the plant by 3 a.m., it took until 11:30 p.m. to stem the flow because so much wastewater had backed up during the previous hour, said Stines.
At the root of the spill was an inability to power the pumps that draw sewage from the lines into the treatment plant. A generator at the plant was fired up in the wake of the power outage but did not supply current. Although the generator had been tested Dec. 6, the test showed only that the generator would start, not that it would produce electricity.
"Unless we put a load on it, we don't know it isn't working," Stines explained. "So we were pretty shocked when we saw it wasn't working."
MSD is required to report all spills that flow into bodies of water to the state Division of Environmental Health within 48 hours and to follow up with a longer report within five days. That report was submitted Dec. 28, Stines said.
Roger Edwards, the state agency's surface-water-protection supervisor, said his department would evaluate the report, including the environmental factors at play and the response of the crew on the scene, but he declined to speculate on whether a fine would be imposed.
For spills involving more than 15,000 gallons, MSD is also required to publish an ad in a local newspaper within 10 days informing the public of the incident.
The large amount of storm runoff and the river's high water level should have diluted the sewage enough that it would not pose a serious health or environmental threat, said Stines.
"In wet weather conditions, I would be surprised if it has any effect at all. It's such a small percentage of the volume of the overall river that it really won't affect it a lot," he said. "A spill that size at the head of a little stream would be significant."
But Hope Taylor at Clean Water for North Carolina noted that the incident highlights some weaknesses in the way sewage is handled — such as the fact that the generator isn't tested for current.
"We need a much more stringent testing procedure there," she said.
After MSD files its report, the DEH has 30 days to determine whether it will impose a fine.