Solid Waste agency experiments with more food waste in compost operation

CEDAR RAPIDS - What happens to the peck of peppers that never get picked in stores' produce departments?

Some fresh produce that goes unsold goes on display each Thursday morning at the Cedar Rapids/Linn County Solid Waste Agency's super-sized compost operation at the base of Mount Trashmore.

On Thursdays, a semi-trailer truck pulls in and dumps a load of unsold produce from the local Walmart and Sam's Club stores. The composting is part of a national Walmart campaign and the local solid waste agency's effort to divert unused food products from the landfill.

It makes financial sense, too.

The Solid Waste Agency charges $18 a ton for compostable material, but $38 a ton for material in the landfill.

The agency hopes its experiment with food waste is just the start. Some 15 percent of what goes into the landfill here is food waste from grocery stores, restaurants and cafeterias, said Marie DeVries, agency planner. The agency's mission, she said, is to divert as much as it can from the landfill.

So what's the catch? The compost pile's location in the city means the recipe requires particular care.

The operation is a low-tech, outdoor affair with long windrows of organic material (food and yard waste) turned in place once a week to promote decomposition. The operation comes with some odor, and keeping the odor under control is one of the challenges.

“So our recipe has to be just right,” DeVries said.

Last summer, the agency experimented with food waste, only to stop because of the odor, DeVries said. The agency concluded that dairy products in the waste came with too much odor and made the compost recipe too moist. The mix can't be too wet or too dry and needs the right blend of carbon and nitrogen in the decomposition, she said.

Another challenge is that diverting food waste from the landfill is not as simple as diverting yard waste, which Iowa has banned from landfills for more than 20 years. Part of the problem for grocery stores and restaurants is collecting the food waste, separating it and then transporting it, she said.

The Solid Waste Agency is in the midst of a local survey of 27 grocery stores to see what those businesses currently do with food waste. To date, 10 stores have responded. None of the 10 separate produce from garbage, and four say they would be interested in composting food waste, said DeVries.

DeVries has updated the Solid Waste Agency Board - which includes Cedar Rapids City Council members and city officials, Linn County supervisors and a Marion representative - on the latest experiment in part to suggest a longer-range discussion about the future of the agency's compost operation.

One of the questions: Should the compost operation move once the Mount Trashmore landfill, which was reopened to take in flood-related debris, closes for good?

City Council member Tom Podzimek, chairman of the board, said it makes sense to revisit the compost issue and he has related questions of his own. Is the current site unsuitable for more food waste because of the odor? Will it continue to make sense for the fall leaf pickup to send a large number of large trucks through Czech Village to the current compost site? What is the challenge and cost to find another site with better technology and a better setup?

DeVries said the compost facility once was an outlet for organic waste from some of the agriprocessing companies in the city, as well as for International Paper's Cedar River Mill. However, the agency backed away from industrial waste because of the amount and the difficulty in controlling the compost recipe.

To take more and different kinds of food waste - dairy and meat, for instance - the agency likely would need better technology, a different site and perhaps an enclosed building, DeVries said.

Iowa City's landfill three miles west of town has been incorporating food waste into its compost operation since 2007. It now takes the material from two University of Iowa residence halls, the New Pioneer Food Co-op and the Regina Catholic Education Center, said Jennifer Jordan, city recycling coordinator.

Jordan said food waste there includes produce, meat and bones, dairy and grains, and Iowa City also uses the same low-tech, open-air windrows.

DeVries said the Iowa City operation is considerably smaller than the Cedar Rapids/Linn County one.