BY: JOLEENE MOODY
Before 2008, if you drove along Route 177 toward the Tug Hill region, you likely saw what you thought was a fire burning off in the distance toward Rodman. The red-hot flames spouting high above the trees prompted many a driver to call 911, certain there was trouble abound. But there was no trouble. What drivers were actually seeing was a landfill flare, a 35-foot flame used for combusting methane gas that is naturally created from a municipal landfill.
The flare was coming from the Development Authority of the North Country’s 75-acre Solid Waste Management Facility in Rodman. Today the flame is rarely lit, thanks to the original 2008 renewable energy collaboration between a landfill-gas power plant operated by Aria Energy (formerly Innovative Energy Systems Inc.) and DANC. Now, instead of burning the methane gas into the atmosphere, the facility is converting the gas into energy, and it’s lighting and heating thousands of north country homes.
“As garbage in the landfill decomposes, there’s a process called anaerobic digestion that takes place that creates a methane-rich landfill gas,” said Emily Zambuto, the manager of environmental programs at Aria Energy. “Some people are under the misconception that we’re directly burning trash to make energy. But that’s not what we’re doing. It’s a much cleaner process.”
The joint venture began nearly ten years ago as a 10 million dollar project, the majority of the financial burden shouldered by the landfill-gas power plant. Today, the project has grown by leaps and bounds, with new wells being added or maintained, and four generators at the plant bearing the responsibility of converting gas to energy.
The process works as follows:
Waste is placed in the landfill. The four biggest volumes the Solid Waste Management Facility receives are:
• Municipal solid waste
• Demolition debris
• Sewage sludge
• Petroleum contaminated soil
After a period of time, a biological process takes place (anaerobic digestion) that will naturally break down and decompose all of these volumes of garbage. As the garbage decomposes, it creates two different gases: 50 percent methane and 50 percent carbon dioxide. The gases are collected via a series of 134 underground wells and then directed by pipelines to Aria, the landfill-gas power plant located directly on site.
Gas isn’t the only product created during waste composition. A liquid called leachate is also produced during the process. Leachate is a liquid that drains, or ‘leaches,’ from a landfill. It varies widely in composition, based on the age of the landfill and the type of waste it contains. Ultimately, to protect the integrity of the biological greenhouse gas, the leachate and the gases need to be separated. Thanks to those 134 intricately built thick, plastic wells, some of which go as deep as 90 feet, the process of separation is done efficiently and effectively.
“The collection of methane is done via a vacuum that is put on the well and, in essence, sucks the methane out of the trash around the well,” said Richard R. LeClerc, Manager of the DANC Materials Management Division. “You can’t effectively do that through liquid, so we need to pump the liquid out. Once the liquid, or leachate, is collected, we haul it to the waste water treatment plants for disposal.”
While the process of “turning garbage into power” is certainly a unique way to create an alternative energy source, it can only work if:
1) The landfill is large enough to generate sufficient quantities of methane.
2) There’s enough interest in private operations (like Aria) to put in a generator.
If these site-specific characteristics are in place, landfills can power thousands of homes for decades. But at some point, the life cycle of the landfill will come to an end, and the process will need to begin either by expanding the current acreage of the site, or investing in a new landfill. As it stands now, DANC is waiting for the approval of an expansion footprint of 100 acres to the south so that the Rodman facility can continue to operate beyond its original site life date.
“In 2008, the projected site life was to expire in 2018,” Mr. LeClerc said. “In 2010, DANC embarked on the proposed expansion and started the process. In 2010, that projected site life had changed to 2021. This past year, as we continue to go through the southern expansion application process and try to get the final permit, there have been continued revisions every year on the estimated site life, and right now, that projected site life is for 2027. But methane can still be produced after that date. On average, once you stop adding waste to a volume, the methane will continue to produce on a declining basis for 20 to 30 more years.”
Aria Energy is hopeful that the permit will be issued sometime this year. In the meantime, they are running three of the four generators at the site, cycling the fourth in and out for maintenance and repair. Three generators, operating at 4.8 megawatts, roughly suggests that one megawatt will power approximately a thousand homes.
“That’s a lot of power,” Ms. Zambuto said. “The gas collected is combusted inside the plant and converted into electricity. The power is then distributed to the grid. We can physically move the power to New England or keep it in New York to power all of those homes.”
Motorists driving along Route 177 toward the Tug Hill region may still be able to catch a glimpse of the 35-foot landfill flare at least twice a year when it’s fired up for testing and maintenance. Otherwise, the flare remains dormant, allowing the joint venture of Aria and DANC to work its magic and produce renewable electricity for years to come.