Cafeteria Composting

Dartmouth College, Dartmouth, N.H., recently was the site for a study on the characteristics and compostability of food service organics, sponsored by the American Forest & Paper Association (AF&PA), Washington, D.C.

Researchers from DSM Environmental Services Inc., Ascutney, Vt., found that laminated paper products, such as milk cartons, cups, plates and bowls, from the college's food service waste stream degraded at a rate consistent with other organics.

"We conducted eight or nine months of research, primarily to understand how laminated paper products degrade in the composting process," says Cathy Foley, executive director of the Paper Group of the AF&PA.

At Dartmouth, employees and students separate food scraps and paper products for composting. According to Elizabeth Ashworth, Dartmouth's campus solid waste manager, roughly 10 percent of the waste stream is diverted via composting and another 30 percent via recycling.

Before being placed into an agitated bay, the organic residuals are mixed with shredded office paper, sawdust and leaves. In the agitated bay, the material undergoes mechanical action but no mechanical grinding.

"Once screened, the final compost has the look and quality of a high-end yard trimming compost," says DSM Environmental Services' John Fay.

Laminated paper cups, plates, bowls and waxed paper degrade at a similar rate, creating acceptable compost for operations with little processing alterations and minimal market ramifications.

"Although the milk cartons degraded more slowly, the laminated paper products degraded almost as quickly as the rest of the material in the compost pile," Fay says of the study. For fiscal year 1999, the university's total waste volume weighed in at 2,307 tons, with 40 percent diverted to composting or recycling.

Foley adds, "We hope that with Dartmouth as a model, other institutions and composters can better assess the inclusion of these types of products at their composting sites."