City considers ongoing use of landfill grinder
Date posted: August 22, 2013
SHERIDAN — Last August, the Sheridan landfill began grinding up construction and demolition waste for a pilot program called, “Will it Grind?”
After a successful, though different than expected outcome a year later, Solid Waste Manager Charles Martineau told members of City Council at a work session Wednesday that the question is now, “Should it Grind?”
Council members expressed enthusiastic support for continuing the program after seeing photos of construction waste from the WYO Theater and Coffeen Elementary School ground into neat, little piles and learning that grinding could add nine years to the life of the landfill.
“Sound the trumpets! This is huge,” Councilman Alex Lee said.
Last year, faced with the possibility of having to build a new, lined cell for construction and demolition waste, landfill staff proposed buying a horizontal grinder to grind up C&D waste instead. The landfill received permission from the Department of Environmental Quality to use the ground up waste as its required daily cover, replacing the six-inch layer of dirt that used to be spread on top of the buried municipal solid waste each day.
“That part of the program didn’t work,” Martineau said.
The ground C&D waste slumped off the face of the trash pile and left small bits of paper swirling in the air, posing problems for litter control.
Landfill staff then started mixing the ground waste — including construction waste and green waste — with the municipal solid waste and burying it all together. They also mixed in wet biosolid waste, decreasing the need to find alternative ways of disposing biosolids.
“It increased our compaction such that we were able to put all that material in there and still gain space in the landfill,” Martineau said. “In fact, over the next two cells that we’re building, the one that we’re currently operating and the next one we’re going to build, we’ll save nine years.”
The mixture of wastes increased landfill compaction by 81 percent.
The landfill is currently filling Cell 9, Phase 1 and will begin construction on Cell 9, Phase 2 next week. Without the grinder, Cell 9 would have reached capacity in 2019 and Cell 10, which is not permitted or built yet, would have been full by 2044. With the grinder, Cell 9 will last until 2024, and Cell 10 won’t fill until 2053. Furthermore, Martineau said, the landfill will not need to expand south for another 40 years.
The grinder also enabled the landfill to lower its construction and demolition waste tipping fees — or dumping fees — from $102 per ton to $45 per ton. Mayor Dave Kinskey asked Martineau to look into lowering the tipping fee even further.
Cons of the grinding program include higher annual equipment operation and maintenance costs; the need for contractors to separate non-grindable construction waste (concrete, large metal pieces, asbestos and other hazardous materials) from grindable waste; and increased staff at the landfill to inspect each load to make sure it’s grindable.
However, the Council felt the pros outweighed the cons and advised Martineau to make the grinder program permanent.
City Council will consider a resolution at its next meeting to finalize the needed permits. Martineau will also present Sheridan’s grinding program at the Wyoming Solid Waste and Recycling Board conference next week.
“I think this is huge,” Martineau said. “Realizing how much space it’s saving in the landfill and not having to come up with the funding to build a new construction and demolition cell, that’s huge for the community, that’s big.”