Mulch Ado About Composting
In her sustainability address in September 2011, President Mary Sue Coleman outlined several goals for the University, including shrinking the amount of waste that U-M sends to landfills by 40 percent by the year 2025. "The Olympic pool at Canham Natatorium? Picture it, filled with trash, over and over, nearly 30 times, and that's how much will not go to landfills," said Coleman.
One way that U-M continues to reduce waste is through composting, a process that transforms vegetative food waste into organic matter that can be used as soil amendment or fertilizer. Originally launched in 1997 as an eight-month pilot, U-M's pre-consumer food waste composting program has expanded to five dining halls, the Hill Dining Center, Pierpont Commons cafeteria, University Catering Services, and Palmer Commons. In the 2011 fiscal year alone, the program transformed 126 tons of food waste into compost.
Recent studies suggest that food waste in the United States is more prevalent than ever. The Environmental Protection Agency (EPA) deems this issue "staggering"; food waste accounts for more than 14 percent of the total solid waste generated in the United States and is the single largest solid waste component reaching landfills and incinerators. Yet less than three percent of the estimated 34 million tons of food waste generated in 2009 was recovered and recycled.
At U-M, the work to change all that begins during meal preparation, when kitchen staff place excess vegetative food—such as fruit and vegetable peelings, egg shells, and plain pasta, rice, and bread—into green compost bins. U-M Waste Management Services staff then collects and transports it to the City of Ann Arbor's compost site. The food waste is mixed with a bulking agent (normally wood chips) and is formed into long piles, or "windrows," where air can circulate and aid in the decomposition process. Once decomposed, the finished compost is tested to assess its potential as fertilizer or soil amendment.
"Compost is simply great stuff. Food waste is a valuable resource that we can use for something productive," says Tracy Artley (U-M '01, M.P.H. '03), sustainability program coordinator with U-M Plant Building and Grounds Services. "But when food waste ends up in a landfill, it decomposes anaerobically, which leads to methane, a greenhouse gas." She points to a statistic from the EPA stating that methane has 21 times the global warming potential of carbon dioxide and remains in the atmosphere for 9-15 years.
Mike Shriberg (M.S. '00, Ph.D. '02), a lecturer in LSA's Program in the Environment and the education director at U-M's Graham Environmental Sustainability Institute, says he has noticed increased student interest in sustainability issues such as composting. In the fall 2010 term, students from his Sustainability and the Campus course conducted a waste audit at the Michigan Union. Decked in hazmat suits, they sorted through a day's worth of garbage—approximately 2,162 pounds of waste—on a loading dock. They found that 23.1 percent of the waste was recyclable and 30 percent of it was made of compostables.
A group of students from the class Sustainability and the Campus sort through a day's worth of waste generated at the Michigan Union. In their coursework, the students concluded that implementing pre- and post-consumer composting programs would redirect approximately 30 percent of the Union's daily waste.
"The students identified an enormous need for diverting waste. Some can be accomplished through waste education, such as increased signage [to promote recycling], but also a lot of it can be done through composting. There's a tremendous opportunity for it," says Shriberg.
Artley says that plans are in the works to expand composting on campus. This will involve implementing post-consumer composting, in which patrons place excess food in composting bins after meals. She notes that the program presents challenges, including keeping costs low, educating campus, and identifying where to take post-consumer material. But Artley is optimistic about what's ahead.
"Our next step is to do a pilot post-consumer program on campus to examine costs and to learn from the experience. From there we'll see how we can expand it to eventually service all of campus," says Artley. "The vision is that eventually all food waste on campus will be generated into compost."