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UMN News: The afterlife of a mattress


NRRI researcher Tim Hagen examines cotton removed from old mattresses that are part of a recycling effort in Duluth.
Photo courtesy of Natural Resources Research Institute
NRRI researcher Tim Hagen examines cotton removed from old mattresses that are part of a recycling effort in Duluth.

Old mattresses are the bane of the landfill. Mostly, it’s the steel springs that landfill managers curse. The springy metal won’t crush. It bounces back, gets stuck in the bulldozers, and takes up a lot of precious space.

“In landfills, it’s all about compaction,” says Tim Hagen, a researcher at the Natural Resources Research Institute (NRRI) at the University of Minnesota, Duluth. “And bed springs just won’t compact. It’s a huge problem.”

Hagen is working on solving the mattress problem with an innovative and aggressive recycling program in Duluth, one of only two in the country where mattresses are taken apart and the components reused. Now in its fourth year, the program gets mattresses from all over the northern half of the state–by the truckloads.

The impetus to recycle took off in 2005 when the Western Lake Superior Sanitary District and Carlton and St. Louis counties instituted a “differential tipping fee” at their landfills and transfer stations, imposing a higher fee to landfill and lowering the cost to recycle. In first year, they recycled 3,139 mattresses and box springs, and this year, they expect to recycle more than 17,000. The mattresses go to Duluth’s Goodwill Industries site where they are cut apart, and each layer of fabric, cotton, and foam padding is pulled off.

NRRI funded a local effort to find markets for the materials that make up a mattress. The foam is easily sold to companies that make carpet underlayment. The wood frames are chipped up and used as a biomass fuel source. And the cotton is mixed with wood fibers for a local company that manufactures oil filters for diesel engines.

“The filter company tested the post-consumer cotton against using new cotton and there was absolutely no difference in performance,” says Hagen. “In the long run, this application saves raw materials costs and preserves valuable landfill space for future generations.”

The filter manufacturer uses about 50,000 pounds of cotton a year, and that’s about how much Goodwill Industries supplies it at the present time.

But what about the pesky steel springs?

The value of steel is at an all-time high, but as mattress springs, they’re practically worthless. Hagen is working with a company that makes baling equipment to see if they can customize a machine to roll the steel up like hay bales.

“Now our challenge is to help Goodwill Industries secure funding to purchase the baler, [which would be designed to safely bale the steel]” says Hagen. “It’s a new concept…but if it works, it will be a win-win-win, all the way around.”

Following in its footsteps

Hennepin County will begin a similar mattress-recycling program in the Twin Cities this summer. (NRRI is working with the county to find a market for the steel and other mattress components.) And the International Sleep Products Association is looking at the Duluth program as a national model for mattress recycling.

By the numbers

9 pounds of cotton in a mattress (average)
25 pounds of steel in a mattress (average)
1,500 mattresses a month to Duluth Goodwill Industries (and growing!)
360 pounds per cubic yard–compaction rate of mattresses
1,600 pounds per cubic yard–compaction rate of garbage without mattresses

Edited from NRRI Now, spring 2008, a publication by the Natural Resources Research Institute.

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