Thanks to a new partnership with local firm Ecotone Renewables, food waste at Pittsburgh International Airport is being turned into fertiliser.
Ecotone Renewables has joined the airport’s xBridge innovation programme, installing one its digesters outside the landside terminal. The system is called ZEUS, for Zero Emissions Upcycling System. Inside the forest green 8ft x 20ft 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, said Dylan Lew, CEO and co-founder of Ecotone.
Employees from the landside Dunkin’ concession drop in about 500lb 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 fertiliser to sell, along with leftover biogas that is purified and used to power the system.
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
At least once a week an Ecotone employee checks that the digester is running smoothly and drains the fertiliser tank via a spigot mounted on the exterior. Other than that, the unit is fully automated and self-sufficient.
“Food waste is bad for business,” said Lew. “I think we’ve created an amazing solution for our customers because we not only reduce waste odours and greenhouse gas emissions, but when it comes down to the bottom line, we reduce costs.”
Coffee grounds offer robust nutrients for fertiliser, and sugary waste like doughnuts and muffins are prime sustenance for the bacteria and microbes that are critical to the digestion process.
“Instead of burning coal to produce this fertiliser and emitting tons of CO2, we’re actually diverting about 90lb of CO2 per gallon of fertiliser produced,” Lew explained.
The digester began operation within about a day of being onsite, Lew said, and doesn’t require the trucking typical of waste management, another environmental saving.
“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 a dozen digesters already in operation, Ecotone has plans to build 15 more this year and more than 100 in 2024. 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.”
Image: Beth Hollerich/ Pittsburgh International Airport
