The decades-long cleanup of Gainesville’s Cabot-Koppers Superfund site is moving closer to its final stages.
State environmental regulators are preparing to renew the site’s stormwater discharge permit with plans to relocate a drainage ditch that previously stalled the remaining cleanup work.
The site, near North Main Street and Northwest 23rd Avenue, was designated a Superfund site by the U.S. Environmental Protection Agency in 1983. The EPA defines Superfunds as locations that are so severely contaminated with hazardous waste, they are added to the National Priorities List. After contamination from former industrial operations affected surrounding soil and groundwater, Cabot-Koppers became a Superfund site.
Cleanup of the Koppers area had been awaiting an agreement to relocate a stormwater drainage ditch that cuts through the site. According to Christopher Gilbert, the hazardous materials program manager for the Alachua County Environmental Protection Department, that agreement has now been completed.
“The entire rest of the project can move forward,” he said. “Everything was hinging on moving and relocating that first because of the way it cuts through the site.”
Gilbert said relocating the ditch will allow crews to move forward with completing a concrete slurry containment wall around the area with the highest levels of contamination. The wall will extend about 80 feet underground with a soil cap eventually placed over the contaminated area.
He compared the containment system to an upside-down bucket in the ground: a fix designed to keep contaminated soil and groundwater within the site and out of the surrounding areas.
Gilbert said nearby residential properties requiring remediation already had polluted soil removed by 2014. However, groundwater contamination will require longer-term precautions and monitoring.
Gilbert expects operations could begin toward the end of this year, with the majority of the remaining site work potentially completed around March next year.
“There will be continued, pretty much forever, ongoing groundwater monitoring of the site,” he said. “Just to make sure that everything has been properly contained and that nothing is moving anywhere.
The Florida Department of Environmental Protection is also reviewing the renewal of an industrial stormwater discharge permit for Beazer East Inc., the company responsible for the cleanup.
The permit would continue the site’s existing authorization to discharge stormwater off the property. Shannon Gore, public information officer for DEP’s Northeast District, said in an email that the renewal continues the same operational practices authorized under the previous permit.
Because stormwater leaves the property through a designated discharge point, it is subject to federal National Pollutant Discharge Elimination System permitting requirements, Gore added. Stormwater at the site is generated through contact with existing solids and sediment.
Temporary controls are in place to manage how stormwater leaves the property until a permanent system is installed. A final stormwater management plan is being developed as part of the Superfund remedial design for the final site remedy, according to DEP.
The site is required to monitor discharged stormwater every quarter, follow best management practices and comply with its Stormwater Pollution Prevention Plan.
Gore said there have been no stormwater discharges from the site or exceedances in monitored parameters over the past year.
“Cleaning up contaminated sites is a complex, multi-phase process but with proper planning and engineering, sites like this can be fully remediated,” she said.
Once the public notice period for the permit is complete, DEP’s next step is to issue the renewal, Gore said.