University Times

Trays have disappeared to reduce food waste and non-recyclable food packaging has been all but eliminated to cut the amount of trash heading to landfills from Pitt’s dining halls.

The latest in Pitt’s ongoing efforts to cut dining hall waste in the name of sustainability is a composting system that can reduce the contents of a 60-gallon garbage can to 15 pounds of flaky fertilizer in a matter of hours.

The aim is to create a closed system in which Pitt’s food waste can be composted and used on the same farms and gardens that produce some of the food eaten on campus.

Market Central executive chef Jeff McClain checks out the compost made from dining hall waste as it emerges from a composter on the Towers loading dock. A new composting system is cutting waste at Pitt’s largest dining facility and providing fertilizer for campus flowerbeds.

Jim Earle, assistant vice chancellor for Business, estimated the composting system’s cost would be recovered through savings in waste-hauling expenses within six-seven years.

The concept had been cooking in the minds of sustainability leaders on campus for several years before the composting system was installed at Market Central last fall, said Sony Rane. Rane, who graduated from Pitt last year with a degree in environmental studies and business, was active in the student environmental group Free the Planet and now is Sodexo’s marketing and sustainability coordinator on campus.

Both pre-consumer waste — such as peelings and other food preparation scraps — and post-consumer waste — uneaten food and biodegradable trash from the 5,000 meals served each day at Market Central — go into the mix.

The process is simple. When plates are returned, staff in the dish return area scrape food, napkins and other compostables such as chopsticks into a water-filled trough that feeds a pulper — think oversized garbage disposal — that grinds the materials into a fine slurry.

The goop travels through pipes under the floor to an extractor where 90-95 percent of the liquid is removed. That “gray water” is recycled for reuse in the system, saving some 90,000 gallons of water annually, Rane noted.

The remaining waste goes into an eCorect digester on the Towers loading dock. There it’s baked at 300 degrees for 18-30 hours before emerging as a low-level nitrogen soil amendment. Mixing it in a 1:3 ratio with carbon-rich brown matter such as dried leaves yields a fertilizer suitable for garden use.

The composting efforts have resulted in an 85 percent reduction in dining hall waste — cutting 20 trash barrels down to the equivalent of fewer than 3, Rane said, and reducing 750-900 pounds of food waste daily to 100 pounds or less.

Last fall, some of the compost went to a local farm that supplies some of the produce used at Market Central. Compost also was used at a student-operated garden on Atwood Street that provides produce for dining hall patrons.

At least one Sodexo manager is testing it on rose bushes at home and Facilities Management plans to use the material on flowerbeds around campus.

The composting system aligns with Sodexo’s company-wide commitment to reducing waste, said resident district manager Susan Fukushima. Pitt’s dining services provider has committed to such sustainability efforts as buying local and sustainably grown foods and cutting both organic and non-organic waste. Sodexo already has switched to compostable takeout containers and uses some biodegradable utensils. It also is phasing out non-recyclable packaging on campus, she said.

That’s important to the composting efforts because tiny bits of plastic — the remnants of single-serve packaging for crackers and fortune cookies — reduce the quality of the finished product.

Fukushima said Sodexo is looking for alternative products to eliminate the problem at its source.

For now, the compost is being given away, but with improved quality, the product could even find a market, Rane said.

Once the process is perfected at Market Central, Pitt’s largest dining facility, composting could be implemented at the Perch at Sutherland Hall and other dining facilities on campus, she said.

—Kimberly K. Barlow