116 3rd St SE
Cedar Rapids, Iowa 52401
- The Linn County landfill in Marion will close in 2044, although it's projected to reach its capacity sooner.
- A new landfill in Linn County is not an option because of zoning restrictions.
- The solid waste agency has narrowed down its remaining options, which include anaerobic digestion and a process that turns waste into energy.
- The new technologies are expensive, so the agency may partner with other municipalities, like Des Monies, to make waste management more cost-saving efficient.
MARION — Most of the materials that pile up in Linn County garbage cans end up in a landfill in Marion, where trash has accumulated since the 1970s. However, that site will close by June 30, 2044 — or earlier, thanks to debris from natural disasters.
“We're going to close on June 30, 2044,” said agency communications director Joe Horaney. “On July 1, 2044, there's still going to be 700 tons of garbage generated (daily) in Linn County that needs to go somewhere.”
With the help of consultant HDR, the Solid Waste Agency catalyzed its search in 2020 by evaluating eight waste management scenarios in its Forward 2044 study. Since siting a new landfill in Linn County is no longer an option, four scenarios remain.
The ideal solution would be a combination of technologies that target different types of waste, divert them from landfills and re-purpose them. In interviews with The Gazette, representatives delved into the tech and explained how robotics, bacteria, heat and more could be used to reduce waste in Linn County.
That innovation will come at a cost: The agency’s board members this week approved a higher fee for bringing garbage to the landfill, which will likely continue to rise to account for future expenses.
That’s why, representatives said, the agency is leaning toward regional collaborations that take advantage of existing infrastructure to make waste reduction cheaper. Several potential partnerships already are in the works.
“We're looking to bring Iowa to a regional level where we would have enough ways to make it economically viable,” said agency Executive Director Karmin McShane.
“The lowest common denominator would be taking material to a facility and considering it waste,” she said. “We would like to take that material to a facility and consider it a resource.”
Using mechanics to sort waste
When you look at your garbage, you may see rotting, useless or tattered materials. In the eyes of the Solid Waste Agency, however, that garbage equals potential. Different types of waste, if handled correctly, are desirable for certain markets and can be reused. It’s just a matter of separating those items from the rest of the rubbish.
Many curbside pickup services already collect trash, recyclables and yard waste separately. In its Forward 2044 plans, the Solid Waste Agency is evaluating mechanical technologies to further separate waste streams and divert more trash from landfills.
Mechanical sorting, or mixed waste processing, separates desirable materials like metals, plastic and cardboard from trash.
Optical sorters, for instance, use light absorbance and reflection to identify materials as they pass by on a conveyor belt. Once identified, a small blast of air underneath desirable items ejects them from the rest of the waste stream, and they can be properly sorted. Robotics and artificial intelligence can also play roles in mechanically separating waste.
Some recycling facilities in Iowa already take advantage of mechanical technologies. Forward 2044 wants to take sorting a step further by applying them to more waste streams.
“There is not currently a facility that is bringing in trash and separating it,” said Kate Bartlet, an HDR solid waste planner and policy director for Forward 2044. “It's the same technologies that are used in recycling facilities now. It's just (changing) what that input stream is.”
Targeting organic waste
Food waste has been the most prevalent component in Iowa’s landfills since at least 1998, Iowa Department of Natural Resources analyses show. Rotting organic waste releases methane — a greenhouse gas that contributes to climate change.
“The biggest thing that we're seeing statewide is the push and the desire to get organics out of the waste stream,” communications director Horaney said.
To do so, the Solid Waste Agency is exploring biological treatments that use natural processes to break down organic waste — like food waste and yard waste — and reduce its volume.
One way to do that is through composting, which the Solid Waste Authority already conducts at a site in Cedar Rapids by Mount Trashmore. There, materials are placed in long rows outside, where they naturally break down within eight to 12 weeks. Less methane is released because of the oxygen-rich conditions, as opposed to compacted materials in a landfill.
The location currently produces 11,000 tons of finished compost product every year. The resulting compost — made from organics that would’ve ended up sitting in a landfill — can be used in gardens, lawns and mulching. Other composting processes are being considered in Forward 2044, McShane said.
The Solid Waste Agency’s composting site accepts:
• Fruits and vegetables
• Baked goods (no sweets accepted: doughnuts, cinnamon rolls, pies, cookies, etc.)
It does not accept:
• Meat products
• Dairy products
• Plastic utensils, bags of any kind
• Paper products (napkins, paper towels, paper plates)
• Any kind of trash
Anaerobic digestion is another biological treatment being evaluated. In giant sealed containers called reactors, bacteria colonies are used to break down waste in the absence of oxygen. The process produces gases — like methane and carbon dioxide — that can be used to generate energy, along with residual materials that can be re-purposed.
The process is commonly used at wastewater treatment facilities, like the Cedar Rapids wastewater plant. The Solid Waste Agency is partnering with the plant to complete a feasibility study by feeding organic waste to the plant’s digesters to create energy. The results — which should be available in the next two months — will determine if building a digester is viable in Linn County.
“We’re hopeful it will be,” McShane said.
Turning waste to energy
After organics and recyclables are separated from the waste stream, that doesn’t mean the rest of the trash has to head to a landfill. Forward 2044 is exploring waste-to-energy processes.
A mass burn facility, for instance, feeds waste into a boiler system where the materials combust and turn to ash. The process produces steam that can be used to generate energy.
Other facilities take the waste, shred it and take out any non-combustible materials. The resulting product — called a refuse-derived fuel — can then be burned for energy. The Solid Waste Agency is evaluating if this fuel could be produced in Linn County and then sent elsewhere for use.
“We haven't determined if that is viable, but it is an example of something that is scalable,” McShane said.
Joining forces is advantageous
To make alternative technologies more cost-efficient, large amounts of waste are needed — larger than what is currently produced in Cedar Rapids. That’s why the Solid Waste Agency wants to band together with municipalities across the Midwest to take advantage of existing infrastructure and waste streams.
“The key piece is there's not just one solution,” said HDR project manager Morgan Mays. “It's really the combination of these scenarios that best suits the region and the area and the waste stream that we have here.”
The Solid Waste Agency has been broaching potential partnerships with municipalities for at least nine months, McShane said.
In Des Moines, for instance, a new state-of-the-art recycling facility was completed in 2021. The Solid Waste Agency may attempt a pilot to transport waste to the facility and potentially bring Des Moines waste back to Linn County’s composting site.
Iowa City is primed for anaerobic digestion, McShane said, due to local interest and existing efforts to minimize organic waste. There could be an opportunity for a partnership with the Solid Waste Authority to create an organics campus where people can be educated about composting, anaerobic digestion and food waste.
While a new landfill in Linn County is out of the picture, the Solid Waste Agency is considering siting new transfer stations in the county, where waste can be prepared for transport to other facilities. Partner landfills in other areas also will be utilized, creating a web of waste management collaboration in the region.
“Rather than saying, ‘We can't do it, we don't have enough waste,’ we want to see if we can do it and bring folks together regionally,” McShane said. “I think doing it now versus doing it in 2036 is key to being successful.”
Brittney J. Miller is the Energy & Environment Reporter for The Gazette and a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues.
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