Scraps to Soil: Composting at Exact Sciences

When peering into a tank filled with 15 tons of decomposing organic material, you might expect to get hit with a towering stink. 
 
But the contents of the 30-foot-long rotating drum instead smell warm and earthy, like a damp forest floor. Which is exactly as it should be, says Ben Stanger, Green Box Compost founder and CEO.  
 
Turns out, the first rule of composting: If it smells bad, you’re doing it wrong. 
 
The small crew at Green Box gets it right. That’s why Exact Sciences works with the Madison-area company to compost waste from its two commercial kitchens.  
 
Since December 2022, Exact Sciences has used Green Box to turn its food waste into compost — a rich, natural, nutrient-filled soil supplement.  
 
Logan Morrow, a farm specialist with Exact Sciences’ food service operations, says that the initiative supports the company’s commitment to sustainability. 
 
“As a larger company, we’re feeding a lot of employees, and that generates food waste,” Morrow says. “By partnering with Green Box, rather than having that waste go to the landfill, we’re able to prevent that from happening and create compost that future food can be grown in.  
 
“We’re decreasing our carbon footprint and lowering our food miles. It just makes sense.” 
 
In 2023, Exact Sciences composted more than 44,000 pounds of food waste created during food prep. Green Box estimates that resulted in roughly 22,000 pounds of compost, reducing Exact Sciences' carbon footprint by about 19 metric tons of carbon dioxide emissions. 
 
Building on that success, the company now is bringing the compost program outside the kitchen to on-site diners.  
 
The larger employee dining areas at Exact Sciences have trash stations featuring two recycling containers and one garbage container. Because Exact Sciences kitchens serve meals mostly on reusable or compostable tableware, on-site dining doesn’t generate many recyclables. So, starting with the company's Madison headquarters, the facilities team has repurposed an existing dining-area station to house one container each for trash, recycling, and compost.   
 
Instead of dumping food scraps, paper napkins, compostable cups, and other items into the trash, employees now can divert that waste from the landfill and into Green Box’s composting workstream.  

How composting works 

Green Box crews collect waste from residential customers and commercial clients like Exact Sciences. They grind up the material in an industrial mixer. Then they add enough carbon-rich material to help with decomposition — dry “browns” to balance out the moist, nitrogen-rich “greens” of food waste. Green Box uses a mix of wood chips, cardboard egg cartons, and pizza boxes to create the right carbon-nitrogen balance for microbial growth. Microbes produce heat, which helps break down the waste.  
 
The mixture moves into the giant rotating drum, which turns every few hours and introduces oxygen to help the process along. Crews monitor the temperature and adjust the mix as needed. Finally, when the batch is cured and cooled, sifters catch any errant plastics or other contaminants. The finished compost gets packaged for residential customers or stored for future delivery. 
 
The chemical reactions of food and other organic materials make composting an earth-friendly practice. In landfills, organic waste produces gases including methane, a potent greenhouse gas that contributes to climate change, according to the U.S. Environmental Protection Agency (EPA). 
 
The EPA says that food is the most common material sent to U.S. landfills, making up nearly a quarter of all municipal solid waste. Municipal landfills are the third-largest source of human-related methane emissions in the U.S., with food producing 58% of landfill methane.  
 
Morrow says that before composting, Exact Sciences kitchens used biodigesters to grind up some food waste and keep it out of the landfill. The machines had limitations, however.  
 
“It was a very small stream of waste we could collect. The biodigesters worked for some food scraps, but no meat, no dairy, no bones, no compostable products, no paper waste, no liquids. We would have to cut down kale stems because they would get stuck in the gears,” he says. “And it smelled so bad.” 
 
Now, all those products can go into the compost collection, including the compostable bowls, utensils, and cups that Exact Sciences offers instead of plastic. Even parchment paper that chefs roast meat on goes into the bin, Morrow says.  
 
The Green Box team drops off a clean, sanitized bin when it picks up a full one. Like on the forest floor, where plant bits become soil that feeds the forest, the food waste will be turned back into earth and produce more food in the future.