TOPEKA, Kan. – Shawnee County is working to address concerns raised by the Kansas Department of Health and Environment about high methane levels and contaminated water in a now-closed landfill.
A closed Shawnee County landfill at 9500 S.W. 21st St. has high levels of methane on the northwest corner of the property and problems with groundwater contamination and methane in the northeast corner.
The landfill closed in the mid-1980s and has been in post-closure care since 1989. Curt Niehaus, director of the county’s public works department, said methane levels at the landfill first started being reviewed in 2009.
The Shawnee County commissioners approved a contract Thursday morning with Terracon Consultants Inc. The contract shouldn’t exceed $37,300 and will be funded by the Solid Waste Department.
Terracon knows “the landfill better than anybody else” and are best equipped to monitor the site, Niehaus said. He said the landfill was created before some modern regulations were in place and said waste cells push the northern boundary of the landfill. More modern landfills provide more room.
“We think we are having a problem with methane and groundwater contamination because these monitoring points are so close to the waste,” he said.
Niehaus said this contract would add more on- and off-site monitoring probes to find the full extent of the issues. The county will know this is a problem if the monitoring points farther from the waste are still finding high levels of contaminants.
“We hope to ultimately formulate a remediation plan for the landfill that satisfies KDHE,” Niehaus said. “The work in this contract has been approved by KDHE, but it is only another step in the chain to bring the landfill into ultimate compliance.”
Niehaus said the landfill doesn’t generate enough methane that can be used but did say trenches could be built. The landfill has a vent system on the east side of the property that collects and vents the gas away.
“We may have to create something similar to that along the northside of the landfill,” he said.