$4M Iowa City composting facility upgrades will improve efficiency, operational capacity

IOWA CITY — The Iowa City Compost and Landfill facility is set to undergo a $4 million transformation, planned to be complete by the end of the summer, that will allow the city to increase the amount of usable compost it produces and at a faster rate.

The project will resurface the existing five-acre compost facility, improve the stormwater treatment and add two more acres. In addition, the city has added a compost turner to improve operational efficiency.

The city is hopeful that the infrastructure and equipment upgrades will eventually allow the facility to process 5,000 more tons of food waste per year.

“… Not only are we adding that two extra acres to give us some more room for where we're doing our processing, where we're interacting with the users of the site … but also increasing that processing time,” Joe Welter, senior engineer for the city, said at a recent city council meeting.

Currently the city is permitted to process 15,000 tons of food and yard waste. The city sells the compost for $20 per ton and regularly sells out. About 3,500 tons of usable compost comes from 15,000 tons of food and yard waste.

Previously, it has taken the city about a year to convert food waste into compost that’s ready to be sold. With the new upgrades it can take as little as three to four months.

Compost turner improves facility efficiency

Part of the transformation is already underway, after the facility acquired a compost turner in June of last year.

Prior to the compost turner, once food or yard waste was dropped off, it was ground up and lined up into rows. The rows were then lifted by an end loader truck and moved to the next row, to mix the piles up. That process could take up to four hours.

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The process, which is called turning, helps speed up the decomposition process by incorporating more air, shifting microbes and distributing moisture.

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A compost turner allows for the compost to be turned once a week, as it only take about 15 minutes to turn one row. The consistent turning shortens the amount time it takes for food waste to be converted into compost.

The city still uses the end loader truck process and is working to gradually incorporate the compost turner over time.

“It's not only saving a ton of time, it's saving all the fuel that it takes to move that from the end loader to running this one piece of equipment ... Ultimately, we'll be able to turn a lot more often because we'll have more time to do it, and then we can move the material through that much faster, because the more you're turning it, the more oxygen is going to get in,” said Jen Johnson, Iowa City’s resource management superintendent.

In addition to turning, landfill staff regularly test the compost for heavy metals. Once the compost is near the end of the decomposition process it’s screened again and sits for a month to return to ambient temperature. The compost can typically get up to 132 degrees Fahrenheit during the process.

City planning to start construction work this spring

The city received a $4 million grant from the U.S. Environmental Protection Agency’s Solid Waste Infrastructure for Recycling program. The city also received a $100,000 grant from the Iowa Department of Natural Resources that will be put toward the project.

The transformation is the culmination of years of work by the city. The city applied for the grant in early 2023, but had already set aside $300,000 for the project at that point.

“This is practical investment that supports. … our sustainability goals, and I think an investment like this will make sure that the facility can continue to serve our community effectively,” council member Mazahir Salih said at a meeting earlier this week.

Iowa City’s facility, located at 3900 Hebl Ave. SW, serves the entirety of Johnson County as wells as Kalona and Riverside. The city is working to secure a contractor for the project and hoping to start construction in April, with a tentative completion date set for the end of August.

The city also is working on outreach to local grocery stores, businesses and schools to divert more food waste to the compost facility as processing capability expands.

Comments: megan.woolard@thegazette.com

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