TOWN OF MENASHA News: Standing in the parks department shop with a Honeywell gas meter in his hands, Randy Gallow slides a metal cover away from a manhole grate in the floor and stands over it for several seconds.
“There’s nothing there,” said Gallow, a streets superintendent for the Town of Menasha, looking at the meter’s digital reading.
He repeats the test in work areas, corners and secluded areas of the building where the air system might not naturally dissipate any gas concentrations.
Since last November, when potentially dangerous levels of methane were discovered in a landfill near the town’s municipal complex, meters have been used frequently to check for evidence of methane gas inside work areas.
While town officials and hired consultants have yet to find methane anywhere inside the buildings, several newly installed outdoor vapor probes have registered methane levels in excess of the lower explosive limit of 5 percent methane.
“If left unmanaged, it could be an explosive situation,” said Christopher Rog, principal geologist/senior project manager for Sand Creek Consultants of Rhinelander. “But we feel like we’ve got it managed.”
In order to further safeguard town employees and the town’s multimillion dollar investment in its facilities, the Town Board this week authorized borrowing up to $527,000 to pursue installation of methane gas mitigation systems in three areas.
“Solid waste and water in all landfills creates methane,” Rog said.
With elevated methane readings so close to the town’s vehicle storage building, he said it is likely that methane has migrated underneath.
A vapor extraction system is the top priority, along with passive venting, both of which should take about three weeks and be completed by the end of August, Rog said.
“These are permanent solutions we are installing,” he said.
Two parallel trenches, one 600 feet and the other about 700 feet, will be dug about 4 feet deep with vent wells that go down to the bedrock spaced every 15 feet. Rog said one trench is connected to an active blower system while the other is connected to an air intake system.
Community Development Director George Dearborn said the town’s E. Shady Lane landfill is split into three disposal sites on the western portion of 116 acres of farmland and gravel pit the town acquired in the late 1960s.
The former town dump is a 12-acre site northwest of the municipal complex. It was closed and capped in the mid-1970s.
A second site, known as the town’s sanitary landfill, consists of two trenches west of Municipal Drive. It was closed in the mid-1980s.
A third site is located immediately north of the town’s Vehicle Storage Building, a large hill on a four-acre site known as the Kimberly-Clark Corp. “greenings pile.” It contains paper sludge from the former K-C Lakeview mill deposited between the mid-1970s and mid-1980s.
Rog said the methane is coming from two primary sources: the K-C greenings pile and the town’s sanitary landfill.
While the town owns the land underneath, K-C owns the “greenings pile” and is responsible for maintaining it. In November, a technician doing routine monitoring smelled landfill gas and confirmed the presence of elevated levels of methane, which was reported to the state Department of Natural Resources and the town.
Since then, K-C has invested a significant amount of money to mitigate methane levels and extend the life of the landfill by replacing the cap, repairing a collection system and expanding its methane collection system, said Christine Spella, K-C communications manager.
“We continue to share information and best practices with the town and the WDNR and are confident their remediation efforts will safely and efficiently reduce the methane levels across the town’s landfill site,” Spella said.
“We will continue to monitor and manage all aspects of the greenings pile moving forward.”
Town Administrator Jeff Sturgell said he does not think there was “any real danger” but town officials have taken the precautionary measures nonetheless.
“Let’s deal with the issue now so that it doesn’t ever become an issue in the future,” Sturgell said.