'Landfills can be desirable features': How they're doing that in DuPage County

Landfills are going to be here forever, so we'd better take care of them.

That's the core idea that Dan Zinnen operates on.

“A concept I'm trying to hopefully share with everyone at the district, and that they will join in on, is that our landfills can be desirable features on the landscape and eventually become indistinguishable from natural areas — if we are good stewards,” said Zinnen, who helps manage eight closed landfills and dumpsites for the Forest Preserve District of DuPage County.

“It takes effort. It takes money. It takes commitment from the district to make things good,” he added.

When well-taken-care-of, closed landfills can have multiple uses. They can generate renewable natural gas, host solar panels and even provide valuable natural habitat.

Atop the district's Greene Valley landfill, for instance, a thriving prairie is home to seven state endangered birds, one state threatened bird and even a gas-to-electric power plant.

At Mallard North landfill, a grove of 8,500 trees treat contaminated rainwater — also known as leachate — while providing sanctuary to local birds and other wildlife.

As director of resource management and development for the district, Zinnen said one of the department's key issues is also “a key issue for the planet as a whole: climate change.”

That's because the eight sites that Zinnen manages produce 97% of the district's greenhouse gas emissions — or 36 times the amount produced from district operations.

The district isn't alone in dealing with the seemingly disproportionate global warming effects of landfills. The disposal sites are a major contributor to climate change statewide, leading all other Illinois industries like mining, metal manufacturing and food processing in methane emissions.

That's because when organic waste like food, paper and yard scraps decompose in a landfill, it produces significant amounts of methane long after disposal. The greenhouse gas is especially a climate concern due to the fact that it holds more than 25 times the warming power of carbon dioxide.

To cut down on the leaks, forest preserve district officials currently implement a range of practices, including converting methane to electricity, burning the gas off and maintaining the landfills' gas collection and cover systems.

In 2021, the landfills and dumpsites produced a total of 765,648 metric tons of carbon dioxide equivalent. When taking into account collection strategies, 166,289 of those tons were released into the atmosphere — the equivalent of 37,000 gas-powered cars driven for one year, according to the U.S. Environmental Protection Agency's greenhouse gas calculator.

Those measurements were collected as part of the district's recently released Clean Energy, Resiliency and Sustainability Plan, which the agency contracted out “to support strategic plan priorities of increasing energy efficiencies and reducing the agency's carbon footprint.”

The district sees the most cuts in its landfill emissions through simply collecting and combusting — also known as flaring — the gas. The practice converts methane into carbon dioxide, therefore releasing a less powerful greenhouse gas into the atmosphere and cutting the district's overall landfill emissions by 78%.

Keeping up with landfill cover and collection system maintenance also is a key strategy.

Typically made of several natural layers like clay, sand and topsoil, a permanent landfill cover is designed to keep gas and leachate in so it can be collected through pipes and properly disposed.

A well-maintained cover will have a symbiotic relationship with vegetation: the cover provides a growing medium for plants, and the plants help stabilize the soil, prevent erosion and offer habitat to wildlife.

Because the district's landfills date between the 1930s and 1980s, they do not have the benefit of such modernized design. Rather, at the time they were built, there was no understanding of groundwater contamination, Zinnen said.

Over the years, the district has had to play catch-up to properly care for the sites and protect the surrounding environment.

For instance, Blackwell landfill, which operated from 1965 to 1971, was categorized as a contaminated site and placed on the national Superfund list in 1990 by the federal EPA due to groundwater safety concerns.

At the time, the site lacked a leachate collection system and had what Zinnen characterized as an “archaic, prehistoric” gas collection system. After efforts by the forest preserve district to install gas and leachate extraction wells were deemed complete by the EPA, Blackwell was finally removed from the list 30 years later, in 2020.

Next year, the agency will install a new system at the site, complete with a flare to burn the gas and more wells to provide for greater gas and leachate collection capacity.

“The landfills are here forever, and they're always going to need special care,” said Jessica Ortega, the district manager of strategic plans and initiatives. “It's unavoidable that landfills are going to continue to emit greenhouse gasses, therefore it's important to explore opportunities to implement strategies to minimize and reduce greenhouse gas emissions from landfills and to care for the sites as naturalized areas.”

Looking further ahead, the agency is eyeing opportunities to operate a gas to renewable natural gas system at Mallard Lake landfill, improve the cover system at the Wheaton dump, and expand the leachate treatment system at Mallard North landfill.

The district also will consider hosting solar panels at its sites, though officials said they will carefully weigh the pros of generating the renewable electricity with other recreational and habitat land uses like scenic outlooks and sledding.

• Jenny Whidden is a climate change and environment writer working with the Daily Herald through a partnership with Report For America supported by The Nature Conservancy. To help support her work with a tax-deductible donation, see

Prairieland at Greene Valley landfill is home to several state endangered birds, including the bobolink and the short-eared owl. The site's gas-to-electricity power plant can be seen in the distance. Courtesy of the Forest Preserve District of Dupage County
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