The SC Department of Health and Environmental Control has found signs that contaminants have leaked into groundwater near a Kershaw County sewage treatment plant, and the agency has told the plant’s operator to protect drinking water wells from pollution.
So far, DHEC and Palmetto Utilities say that nitrate — a toxin often associated with sewage — has not been documented at unsafe levels in private wells near the company’s wastewater system.
But DHEC and Palmetto signed a consent agreement in July that says the company must develop a plan to prevent “potential adverse impacts to drinking water supplies in the area that may have been or may in the future be related to operations at the site.’’
The agreement says nitrate contamination in groundwater may extend back more than 10 years. Agency documents dating to 2000 show increases in nitrate levels in shallow groundwater near the company’s sewage disposal basins, according to the July 30 agreement.
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Nitrate concentrations have exceeded groundwater pollution standards near the basins on at least five different occasions since Aug. 6, 2013, the agreement says. The document says water seeping through the ground also contained elevated nitrate levels in 2010, which indicates the presence of wastewater.
DHEC and Palmetto Utilities officials said Wednesday that drinking water in the area is safe. The company has notified area landowners that their wells are not contaminated. Palmetto also said it had addressed the seepage problem.
“Wells continue to have positive results for the quality of the drinking water,’’ Palmetto spokesman Rick Melcher said, noting that there has been “no impact.’’
Still, the groundwater issue and a recent 870,000-gallon raw sewage spill into Spears Creek may come up at a town hall meeting Thursday night about a Palmetto plan to expand its wastewater system by adding a discharge to the narrow creek. Palmetto is seeking DHEC permission to roughly double the amount of treated wastewater it discharges, records show. The company now is permitted to release about 6 million gallons per day to disposal basins in Kershaw County.
Company officials say the increase in capacity is needed to keep pace with growth, including a 500-home housing development in the Blythewood area that has drawn criticism from area residents.
State Sen. Vincent Sheheen, D-Kershaw, said he’s unconvinced the company needs to increase discharges when it has had problems at the existing plant. He also questioned discharges to Spears Creek, a relatively small tributary of the Wateree River that he said may not be able to absorb the wastewater. Melcher disputed that.
“The biggest issue is the facility not being able to handle the capacity and not being upgraded,’’ Sheheen said. “We’re seeing potential groundwater and surface water contamination. Both of these are really bad.’’
The Sept. 23 spill by Palmetto Utilities into Spears Creek occurred after an electrical component in its treatment plant failed. Not all of the 870,000 gallons that spilled reached the creek, but Melcher said the release should not have occurred. He said the company has since added backup equipment to make sure the system continues to operate if the front line equipment fails.
Palmetto’s Kershaw County sewer system serves about 25,000 customers, mostly from areas in northern and northeast Richland County. The business is a subsidiary of Ni America, a company that also owns other private wastewater providers in the Columbia area. Among those is the old Alpine treatment plant along the Saluda River.
The town hall meeting on the company’s discharge plan is scheduled for 6 p.m. at the North Springs Community Center, 1320 Clemson Road.