The County Farm Drive Landfill off Al Bishop Drive faces the same methane leakage problems that caused officials to intervene at the nearby, but smaller, County Farm Road Landfill off County Services Parkway.
Even though construction has already been completed at County Farm Road Landfill, the board has yet to approve funding for the project.
“(The) county manager has authority in some emergency circumstances, such as the first landfill, to proceed without board action,” county spokesman Robert Quigley explained. “But (they) must come back at the next commission meeting to have the action ratified. That is what’s happening here.”
County Farm Road Landfill opened its doors in 1980 and accepted its last load of waste in 2000, said Jonathan Jenkins, director of the county’s Solid Waste Department.
County Farm Drive Landfill opened in 1972 and closed in 1989. The county is home to one additional closed landfill at Cheatham Road.
Today, Cobb has no active landfills, and waste is instead transferred to stations in other counties, according to Jenkins.
In its heyday, County Farm Road Landfill took in construction and demolition debris. County Farm Drive Landfill was a sanitary landfill, Jenkins explained, which means it was once a destination for household garbage.
Jenkins explained why the county is requesting $731,000 to clean up the two landfills.
“All landfills generate methane. We are required to ensure that no methane leaves the property,” Jenkins said. “We have a system of methane monitoring wells that we monitor on an ongoing basis.”
An explosive gas
Methane is the principal component of natural gas, explained Mark Mitchell, chair of Kennesaw State’s Department of Chemistry and Biochemistry.
“The most dangerous aspect of it is the fact that it’s explosive,” Mitchell said. “It’s not toxic, like carbon monoxide.”
Mitchell said methane is released from landfills when bacteria start to decompose waste and release gases in the process.
According to the Environmental Protection Agency, landfills rank as the third leading source of methane emissions. Mitchell cautions methane can also be a very potent climate change gas. “It works in the same way as carbon dioxide,” Mitchell said. “But the effect is much stronger.”
Jenkins said his department detected methane levels approaching the legal limit at the County Farm Road Landfill and realized something needed to be done. State environmental officials notified the county of potentially dangerous methane concentrations outside the bounds of the landfill in November 2013, according to the county’s agenda.
“We had to start investigating different ways to capture or redirect the methane,” he said.
Officials set a cap of $235,000 for the County Farm Road project, which is technically not yet finished due to a mandated monitoring phase that must continue for six months after construction, Jenkins said. The Solid Waste Department will thus request a total of $731,000 at today’s meeting to cover the expenses of both projects — one that was completed in an emergency capacity and one that has yet to begin.
“It’s something that needs to be dealt with,” said Commissioner Bob Ott, who plans to vote to approve the funding. “It’s part of the county’s responsibility after you close a landfill.”
The EPA requires landfills to remain under post-closure care for a minimum of 30 years after the operation stops. Federal regulations stipulate how much methane can leave the property, and the state’s environmental department enforces those guidelines.
Jenkins said methane levels are sometimes much higher within the landfill’s boundaries, which is permitted as long as the concentration dissipates once it reaches the boundary lines of the landfill.
“If you have a leak or anything during that 30-year period, you have to fix it and come into compliance,” said Commissioner JoAnn Birrell. “Unfortunately, it’s a cost we have to incur, but it comes with your 30-year post-closure agreement.”
Jenkins said methane gas can travel great distances underground, and officials were concerned the gas would leave County Farm Road Landfill by leaking underneath the roadway.
A system of removing methane from the ground, called an extraction well, was developed as the solution, Jenkins said.
The county tapped Jacobs Engineering, the company already responsible for managing Cobb’s water systems, to build the well along 750 feet of the west side of the landfill, which is adjacent to County Services Parkway.
Jenkins said the county plans to build a similar, longer extraction system along the edge of County Farm Drive Landfill before a methane problem develops beyond property bounds.
IF YOU GO ...
WHAT: Cobb County Board of Commissioners
WHEN: 9 a.m. this morning
WHERE: 100 Cherokee Street, Marietta