Wilmington landfill uses latest technology for Delaware's trash

By Rachel Sawicki
Posted 12/2/21

WILMINGTON — It’s time to take the word “dump” out to the trash.

Open dumping of trash in the United States was banned in 1976 under the Resource Conservation and Recovery Act, but well-run, modern landfills can ultimately benefit the environment and vary widely from the problematic facilities of the mid-20th century.

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Wilmington landfill uses latest technology for Delaware's trash


WILMINGTON — It’s time to take the word “dump” out to the trash.

Open dumping of trash in the United States was banned in 1976 under the Resource Conservation and Recovery Act, but well-run, modern landfills can ultimately benefit the environment and vary widely from the problematic facilities of the mid-20th century.

Wilmington’s Cherry Island Landfill is one of the most advanced in the country, serving as a model for the future of waste management.

“A lot of people don’t think of landfills in a positive light,” said Mike Parkowski, chief of business and governmental services for the Delaware Solid Waste Authority. “They think it’s a negative thing because all this trash is there, but what they don’t understand is that the landfill is actually protecting them from the trash. So if we didn’t have landfills, trash would just be out in the open.”

On the west side of the Delaware River, the 513-acre Cherry Island Landfill opened in 1985. Every landfill will eventually run out of room, but Mr. Parkowski said Cherry Island has several decades of space left.

“We also have other options, like the areas that we own, but we haven’t developed yet. ... That would give us another 50 to 100 years,” he added.

Mr. Parkowski said around 400,000 tons of material comes to Cherry Island each year, and 350,000 tons of that actually goes into the landfill.

In the last 20 years, several civil and environmental engineering projects helped add decades of life to the facility. Also, in 2011, the landfill’s expansion project was selected as a finalist for the Outstanding Civil Engineering Achievement Award by the American Society of Engineers, one of the most prestigious awards in that field. The project was one of the most massive reinforced-earth berms ever used in an environmental application, standing 60 feet high and 8,000 feet long.

According to the Solid Waste Association of North America, the wall addresses “the extensive design and construction issues associated with building a landfill expansion over unconsolidated sediments (and) a pioneering foundation improvement design technique that analyzes the performance of prefabricated vertical drains.”

Cherry Island also has an extensive gas-collection system.

Facility engineer Alex Steuerwald said there are about 200 wells that run to the bottom of the landfill and “vacuum out” the emissions. The gas travels to a plant on-site, where it is converted into clean energy and reused.

He added that landfill gas is completely renewable, similar to solar, wind and other alternative energy, because there are no fossil fuels being pulled from the ground.

“We don’t want anything going into the air. We want to try and capture all of it,” he said. “That’s why every single day, the wells are checked to make sure that they’re pulling good gas.”

Mr. Steuerwald said the gas-collection process also prevents odors.

“We’ve got a properly managed gas-collection system,” he said. “That’s how we try to negate any sort of odor leaving the site.”

Mr. Parkowski noted that the facility has not received any odor complaints in almost 20 years, but that it is often blamed for nasty smells in the area.

“There used to be a lot of odor-contributing facilities between here and Claymont, and no matter who it was, people would be like, ‘It’s the landfill,’” he said. “But I think the No. 1 thing that gets preached here is, no odors. That is our No. 1.”

Furthermore, trash from Delaware stays in Delaware.

Mr. Parkowski said Cherry Island does not accept trash from nearby cities in Pennsylvania and New Jersey, nor does it need to export any trash overflow out, thanks to the state’s robust recycling procedures.

Around 10% of the volume that comes through the facility is from residences, and every vehicle that enters, whether personal or commercial, is weighed coming in and weighed going out to account for how many tons of trash are dumped and to calculate costs.

Not everything can be thrown in the landfill, however. Mr. Steuerwald said spotters at the dump do their best to catch things like tires, scrap metal, yard waste and drywall. There are separate piles for those things at the facility, which conserves space there.

“If we don’t send it to (organizations that sell these materials), we reuse it,” he said. “One of the big things we do here is we collect all yard waste and shred it into a finer material to use as topsoil on our slopes and (to) grow vegetation.”

The daily cover put over the dump spot, or “working face,” each day is a reused material, too. Soil from construction sites that have been cleaned of contaminants is mixed with other dirt and stones and packed on top each day, so trash is never left unexposed overnight.

“We’re not using virgin soil. That’s the benefit,” Mr. Parkowski said. “So we’re not digging a hole in the ground somewhere else and taking that soil out. We’re reusing soil.”

Mr. Parkowski described the landfill as one big “bubble.” All the gas and water gets “sucked out” and cleaned, so there’s no negative environmental impact. In fact, a natural habitat surrounds the facility, and once a landfill is capped, it becomes protected property where animals can thrive. Buildings cannot be built on landfills, but some have been transformed into golf courses or parks.

“There’s a lot of wildlife that lives here,” he said. “In a city setting, it actually is kind of a good place for them to be because they’re not in the trash. They’re on the outskirts. And when we’re done, all that’s going to be left here is a grassy mountain with a bunch of trees. It’s almost like a sanctuary for wildlife.”

Ultimately, Mr. Parkowski said the systems and technology at Cherry Island Landfill keep people safe. He noted that, in some underdeveloped countries, people still get sick and can die due to mismanagement of trash.

Additionally, uncovered landfills contribute to the large amounts of trash in the ocean.

“The plastic is already out there, but you can stop it from getting into the ocean every day,” Mr. Parkowski said. “There are people out there in ships trying to collect it, but it’s like a bathtub that’s filling up, and you’re taking water out with a Solo Cup. Eventually, it’s going to fill up because you’re not turning the spigot off. And that’s what landfills do. Landfills turn the spigot off.”

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