Airport Partner Turns Food Waste into Fertilizer

By Matt Neistei

Published May 26, 2023

Read Time: 3 mins


49The next time you stop for coffee and a muffin at the Dunkin’ concession in PIT’s landside terminal, you’ll be helping to reduce the airport’s carbon footprint.

Aviation accounts for 2-4 percent of global carbon emissions, but 8 percent of greenhouse gas emissions are produced by food waste in landfills worldwide, as calculated by the United Nations.

And while Pittsburgh International Airport is actively working to cut back aviation-related emissions, it’s tackling the larger problem as well, through a new partnership with Pittsburgh-based Ecotone Renewables.

“Food waste is bad for business,” said Dylan Lew, CEO and co-founder of Ecotone. “I think we’ve created an amazing solution for our customers because we not only reduce waste odors and greenhouse gas emissions, but when it comes down to the bottom line, we reduce costs.”

Healthy digestion

In April, Ecotone joined the airport’s xBridge innovation program and stationed one of the company’s digesters outside the landside terminal. The system is called ZEUS, for Zero Emissions Upcycling System.

Inside the forest green 8-foot by 20-foot cargo container is a complex system of pipes and tanks that takes the concept of composting waste and supercharges it—about eight times faster than normal composting, Lew said.

An employee comes by once or twice week to make sure everything’s running smoothly and to drain the fertilizer tank via a spigot mounted on the exterior. Other than that, the digester is fully automated and self-sufficient.

Think of the system as a giant stomach. Employees from the landside Dunkin’ concession drop in about 500 pounds of food waste a week via a chute on the outside of the container. The waste is then ground up, mixed with collected rainwater and fed through the system.

Three weeks later, Lew’s team has 50 gallons of nutrient-rich fertilizer to sell, along with leftover biogas that is purified and used to power the system.

“It’s been amazing working with the airport and especially Dunkin’ and the Hudson Group,” Lew said. “That was actually one of our goals: to dispose of their food waste because of the type of waste they have.”

It turns out coffee grounds offer robust nutrients for fertilizer, and sugary waste like donuts and muffins are prime sustenance for the bacteria and microbes that are critical to the digestion process.

The carbon-negative fertilizer they produce—compared to industrially produced synthetic fertilizers—is another key element of the company’s sustainability mission.

“Instead of burning coal to produce this fertilizer and emitting tons of CO2, we’re actually diverting about 90 pounds of CO2 per gallon of fertilizer produced,” Lew said.

Community benefit

Ecotone donates 10 percent of its “Soil Sauce” fertilizer to local community gardens. Of the rest, about 95 percent is sold to about three dozen farmers in 100- to 1,000-gallon orders, and the remainder is bottled and sold to home gardeners at about 50 retail locations.

The digester began operation within about a day of being onsite, Lew said, and doesn’t require the trucking inherent to typical waste management, another environmental savings. ZEUS fits right in with the airport’s xBridge innovation program, launched in 2020, which has a proven record of working with both established and startup technology companies to develop tech solutions for aviation and other industries at PIT.

“We were very excited to get Ecotone’s digester here because it offers solutions to multiple challenges for us,” said xBridge Director Cole Wolfson. “Their vision of sustainability and commitment to the community align with our values, and we think this technology has incredible potential.”

With about a half-dozen digesters already in operation, Ecotone has plans to build 15 more this year and more than 100 next year. The company’s sustainability ethos paired with the economic benefits of the digester has strong appeal for customers, Lew said.

“It costs money to haul food waste to landfills, and we are instead taking those otherwise lost nutrients and revenue and putting them back into the food system,” Lew said. “This all happens within a 15-mile radius and helps strengthen our local food system while improving long-term soil health.”

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