Smith Mountain mine reclamation using biosolids
Mar. 2—Large trucks began making their way up and down Smith Mountain in Cumberland County last fall, taking tons of material to a former coal mine.
The trucks were a visible sign of the early stages of a mining reclamation project using biosolids from a wastewater treatment facility in Chattanooga to the rural site.
Karen Styers, with the Moccassin Bend wastewater treatment facility, told the Chronicle about 7,000 tons of biosolids had been taken to the site ahead of a prescribed burn at the location.
"Once the controlled burn has taken place, the city's contractor, Synagro South, will land apply the biosolids material and then the area will be seeded in an attempt to reintroduce native vegetation," Styers wrote in an email.
Biosolids are nutrient-rich organic material left over from the treatment of domestic sewage. It's often used as fertilizer and soil amendment to promote plant or crop growth.
The use of biosolids as fertilizer is common. The city of Crossville's wastewater treatment plant allows farmers in the community access to the biosolids produced there.
The Tennessee Department of Agriculture has approved use of class B biosolids as a fertilizer.
It can seem like a win-win situation — farmers can access a nutrient-rich fertilizer and municipalities save on the cost of landfilling the sludge left from wastewater treatment.
However, some jurisdictions have begun questioning the use of biosolids on farmland.
In Maine, farmers have found high levels of Per- and polyfluoroalkyl substances, called PFAS, in the soil and water farmers believe are linked to the use of biosolids in years past. PFAS have been linked to numerous health concerns.
In mine reclamation projects, primary concerns are potential soil or water contamination, which is why the process is regulated by the Tennessee Department of Environment and Conservation.
Representatives of the Office of Surface Mining Enforcement and Reclamation contacted Chattanooga in 2021 about using biosolids at the Smith Mountain site.
Chattanooga distributes biosolids to about 190 farms in Tennessee and Alabama, and has provided biosolids for mine reclamation in Copperhill, TN.
After multiple visits to the site, Chattanooga applied to TDEC for a permit to land apply Class B biosolids on about 170 acres. The permit was approved in March 2022.
"Working out details with federal and state regulators took some time, so transportation of biosolids material to the site did not begin until November 2022," Styers said.
While the state approved bringing up to 10,200 tons to the site, Chattanooga reduced the amount to allow for an expanded buffer zone at the site, she said.
"Application at the Smith Mountain site will be monitored closely by the city [Chattanooga] as well as federal and state officials to ensure the required buffer zones are enforced and to ensure there are no issues or concerns that need to be addressed," Styers wrote.
Project completion is slated for mid-April.
The former coal mine in rural Cumberland County has not been in use for many years. In 2009, the mine was at the center of controversy following a proposal to bring coal ash from Kingston following a 2008 coal ash spill that devastated that community. The plan, eventually turned down by the county, would have used the site for ongoing coal ash disposal following that clean up effort.
The proposal resulted in a lawsuit filed by residents of the area after the Cumberland County Commission voted in favor of allowing the landfill. The suit was appealed to the Tennessee Supreme Court, which ruled in 2011 that Chancery Court should conduct a review of the commission's decision. The suit was dismissed in February 2013, and the coal ash landfill was never constructed.
Heather Mullinix is editor of the Crossville Chronicle. She covers schools and education in Cumberland County. She may be reached at hmullinix@crossville-chronicle.com.
