Polk County had a $2.5 million problem at its landfill.
At issue was the cost and treatment of leachate (LEE-chayt) – the liquid that filters to the bottom of the landfill at tens of thousands of gallons per day. Polk County officials have been hauling it to a treatment facility offsite for $2.5 million a year because they were not able to treat it onsite.
It is a common practice for solid waste departments. As landfills grow, the volume of leachate increases; many Florida counties are seeking cost effective and sustainable ways to treat their leachate.
In Polk County, University of Florida researchers have solved the problem.
A team from UF's Engineering School of Sustainable Infrastructure and Environment with the Herbert Wertheim College of Engineering designed a complex and sustainable wetlands-filtration system that could serve as a model for other counties.
"Our wetlands-treatment system is designed to reduce or completely eliminate the county's dependency on third-party transporters and treatment services," said Dale Henderson, director of Polk County Solid Waste. "We have a tremendous partnership with the University of Florida and are extremely proud of this facility."
Henderson spoke on Sept. 10 during a media event at the Polk County landfill to introduce UF's new leachate-wetlands treatment facility and a new on-site renewable natural gas plant that turns landfill gas (methane) into energy to sell.
County officials touted these new sustainable initiatives amid news that it would discontinue curbside recycling for residents in the unincorporated Polk County. Polk is not alone in discontinuing its curbside program; vast market fluctuations in recycled materials have forced municipalities to re-evaluate.
Thus, the county tempered the curbside news last week with the introduction of the new green initiatives at the landfill.
In 2019, Polk County officials asked UF researchers to explore more sustainable leachate management practices. Led by UF engineering professors Tim Townsend, Ph.D., and Steven Laux, and Ph.D. student Dreyton Lott, UF researchers developed a wetlands-based system to treat landfill leachate.
"Leachate contains ammonia nitrogen that can be treated effectively using constructed wetlands, a low energy alternative that uses natural systems to treat leachate," Laux. noted.
