FARGO — As far as stink goes, the Fargo and Clay County landfills are working to keep any smell to a bare minimum.
Both are currently working on expanding methane gas collection systems. As garbage decomposes, it releases methane, carbon dioxide, water vapor and other gases that can create a strong odor.
However, extraction wells can tap into the gases deep inside garbage mounds or cells and pipe it away where it can be refined. It then emerges as mostly methane, the combustible component of natural gas.
At the 160-acre Fargo facility, one of the few urban settings for a landfill in the nation, Solid Waste Utility Manager Terry Ludlum said a $3.9 million expansion project is nearing completion. The project will turn a portion of the methane gas into a cleaner-burning natural gas quality product that can be used in a variety of ways.
Some of those options include selling it to Xcel Energy and piping it into the nearby natural gas pipeline; constructing a fueling station and burning it in natural-gas powered garbage trucks or other city vehicles; using it to power more electrical generators that produce salable electricity; or increasing its use as a heating fuel for landfill buildings.
Ludlum said he'll leave the decision to the Fargo City Commission, although he still has some research to do on federal incentives to make any of the projects more cost effective.
"We want to make sure the City of Fargo leaders understand the opportunities, any risks and then figure out a long-term plan that can be implemented in the next year or two," he said.
- First they came for plastic bags, coffee cups are next
The landfill sells methane gas and pipes it about 1.5 miles to a Cargill plant in West Fargo and also uses it to run generators that feed electricity into the Cass County Electric Cooperative grid that runs nearby. That provides about $100,000 to $150,000 in revenue annually from Cargill and another $250,000 to $300,000 from the co-op. The gas is also used to help heat the transfer station at the landfilll, saving $75,000 a year in heating costs, Ludlum said.
Since the system was first built in 2001, it has generated about $6.2 million in revenue as Cargill began buying methane that year and the electric cooperative signed a deal in 2007. The revenue figure increases when adding in federal energy saving deals and an estimated $775,000 in building heating cost savings at the landfill.
When the current project is done in June, Ludlum said about $7 million will have been invested in the system, with the remaining $800,000 to $1 million in costs to be recovered in the coming years.
The current project won't increase the 60 gas collection wells scattered across the landfill, but rather involves replacing original compressors, a flare and landfill gas conditioning equipment. It also includes an enhanced piece of equipment that will remove hydrogen sulfide and siloxane from the methane gas to produce the natural gas product.
Ludlum said the landfill has an estimated life left of 25 to 30 years, but that could be extended by three years if the waste stream can be reduced by 10 percent. He said the city will study residential and commercial garbage to see if a technology exists to reduce that waste.
Across the river, Clay County commissioners recently approved drawing up plans for an estimated $2 million to $2.5 million expansion of methane gas collection at its 40-acre landfill about 7 miles southwest of Hawley.
Solid Waste Manager Kirk Rosenberger said the county board unanimously approved a hybrid project that will use some of the methane gas in a boiler that will heat a shop at the landfill used by the county highway department and the landfill.
The focus, however, is to manage the gases that release the odor. To do that, the project involves relocating and constructing a new flare on the north side of the landfill that Rosenberger said would be more effective in controlling odors than other options. The flare would burn off the methane gases.
"We're concerned about the odors and want to be a good neighbor," Rosenberger said.
Yet another phase of the project involves expanding the number of well collection sites in the landfill from six to almost 20.
The projects will likely be bid later this summer to allow time for engineering and design of the system.
Unlike the much larger Fargo landfill, the Clay County landfill is smaller and doesn't have enough methane gas to fire generators, for example, to sell electricity, Rosenberger said.
The landfill, he said, has other efforts underway that will help keep garbage out of the landfill. One that takes away about 8.5 tons of garbage annually from the county is a five-county garbage to power plant in Perham that benefits three industries there. Rosenberger also said that curbside, single-sort recycling programs are being planned for the county's smaller cities of Dilworth, Barnesville, Hawley and Glyndon.
Other efforts, he said, include the work of a task force on plastic bag litter and collection programs for electronics, household paint and other hazardous products as well as pesticides from county residents.