Composting Food Residuals on Campus


Courtesy of BioCycle Magazine

Two professors at the University of Wisconsin-River Falls (UW-RF) have used their knowledge of organics recycling projects to implement a food residuals composting program on campus. “It just makes sense in the long run to divert these materials now and lay the groundwork for the future,” says Bob Butler of the Agricultural Engineering Department, who is working closely with Jerry Nolte, an Agricultural Economics professor. “This is useful material, which we think can be composted successfully in an economical way.”

They outlined a step-by-step approach for designing and launching the project: 1) Conduct an audit of the university’s sources and amounts of wastes, varieties of materials being discarded, methods and costs of disposal. 2) Identify materials available for composting and what might be available in the future. 3) Prepare plans for waste collection, transportation and composting. Include permit requirements, equipment needs, method and frequency of collection and labor required, compost site plan, and provisions for year-round operation of the compost facility. 4) Implement the composting process and monitor performance. Measure and record the quantity and types of materials diverted, material characteristics (such as volume, density, moisture content, C:N), collection and transportation, processing costs, and amounts and quality of compost produced. 5) Measure the environmental impact on the compost site. Monitor changes in soil, soil nutrients, surface water, air quality and numbers and varieties of vermin in the vicinity of the compost windrows. 6) Evaluate the economic sustainability of campus-wide composting. Include the cost of landfilling and recycling and the value of the finished compost.

Funding was provided through a $60,000 Waste Reduction and Recycling Demonstration Grant from the Wisconsin Department of Natural Resources’ Bureau of Community Financial Assistance program and matching funds from the UW-RF. The first step was to gain the support of the school’s administration. “At first they were skeptical but neutral to the idea,” says Nolte. Citing the success of similar programs in Washington State, “they (the administration) didn’t see any reason not to back us as long as we didn’t harm anything.”


UW-RF serves meals to 5,500 students and approximately 500 faculty and staff through fast food restaurants and two cafeterias, generating about 500 pounds/day of food residuals. The food service provider on campus is responsible for the cost of waste disposal from its kitchens. Nolte and Butler met with the food service managers and found them to be “very supportive from the beginning.” Together, Nolte, Butler and company managers evaluated the kitchen facilities to identify key locations for placing containers. They chose bright red, 32-gallon containers on wheeled carts to allow for flexibility in location and ease of transport to the loading dock.

Organics such as meat, cheese, plant materials and soiled paper products are collected six days/ week during the school year and on an on-call basis in the summer months. (Lack of space in the fast food kitchens limits the number of barrels that can be used there; some compostables still end up in the gar-bage disposal.) The containers in the cafeteria kitchens are lined with compostable bags since grease from the meats make unlined barrels more difficult to clean. Student workers wheel the containers from the kitchens to the loading dock. Containers in the common areas are lined with conventional plastic bags to keep down expenses. Janitorial staff collect the bags from the common area and place them in a barrel outside the building near the loading dock.


Contamination of the compostables collected from the kitchen is virtually nil, which Nolte and Butler attribute to a solid connection to the food service management and a strong education program at the onset of the project. On the other hand, contamination in the common area is much higher and includes plastics such as straws, cup lids and cutlery. When students are unsure of where something goes, they generally throw their whole tray into the trash. Contamination decreases as the students become more educated about the process, although progress is slow. Nolte cites affordable degradable food service items as a prime need in this system and others like it. The big question is whether the higher cost of such items are greater than the savings from not landfilling the recoverable organics.


Student workers transport the red barrels and bags via pickup truck to the university’s Mann Valley Farm, located four miles from campus. (Nolte and Butler were required to permit the site as a regular solid waste compost facility.)
 Plastic bags are sliced open and emptied, and contaminants are removed by hand. Windrows are formed without shredding or grinding of material and the piles are oriented to the slope of the soil surface. The windrows are then covered with a thick layer of animal bedding and manures. Piles are monitored for temperature, watered and turned with a WildCat as needed, but otherwise, very little active management takes place.

There has been no problem composting any of the materials in the size and form in which they have been received, including whole watermelons and melons, large pieces of cardboard and meat. In fact, composting meat proved “surprisingly easy.” There were no problems maintaining temperatures during the frigid Wisconsin winters, which had been a concern initially. Vector attraction has been limited to an occasional farm cat and mice. The compost is being used on the farm.


Intrigued by the cafeteria and fast food restaurant successes, student Scott Schlichter decided to try collecting compostable materials from the dormitories. He began a pilot project with nonrecyclables such as pizza boxes from one residence hall for three months. After initial success, he received an undergraduate research grant from the University of Wisconsin Solid Waste Research Program to expand the project to eight more residence halls.
Schlichter conducted a waste characterization study, determining that 34 percent of all material discarded in the dormitories was compostable. He placed collection containers next to the receptacles for cans and bottles in the dorms. Spoiled fruits and vegetables, old bread, pizza boxes, paper plates and napkins, paper towels, paper milk cartons, newspapers, magazines, and microwave popcorn bags were collected and transported with the other compostables to the farm. Two percent of compostables were recovered.

Nolte and Butler also initiated collection of compostables from laboratories in the Agricultural-Science Building. Plastic bag-lined containers stationed alongside the standard waste receptacles were emptied twice weekly and transported to the farm. Eighty to 90 percent of what would have gone into the trash was recovered. “The most difficult aspect of this part of the project was to get the janitorial service to buy into it,” states Nolte.


The cost of material collected was $59.55/ton. This included the vehicle and labor for collection and six round trips/week to the school farm, processing at the farm and equipment, including the red barrels and all labor except for Nolte’s and Butler’s. These costs can be reduced by increasing volume and reducing trips to the farm from six/week to three/week. This would require interim storage on the loading docks outside the cafeteria and fast food facilities. The cost per ton strongly suggests that a composting program such as this one should be economically feasible for many institutions.
Nolte and Butler have identified two problems with sustaining and expanding composting programs such as that at UW-RF. First, contracts with waste haulers are not usually on a weight basis. This means it is difficult to calculate accurately the amount collected and hauled. A pay-as-you throw pricing system for waste disposal would help development of composting programs.
Second, utilities such as waste disposal at institutions like university campuses are often paid for by the state. In these cases, a campus that adds a composting program with the associated internal costs probably will not see any cost savings even if the waste hauling bill goes down.


The programs at the University of Wisconsin-River Falls show that composting on campus can be done in a routine way that involves little supervision or overhead and with little change in the waste collection system. Campus-wide composting made a significant impact on diverting food residuals from the landfills and has the potential to divert a significant amount of material from the dormitories. Large investments of capital are not necessarily required for collection or composting. Vital components for a successful program include: Top administrative backing; Operational supervisors as part of the planning team; Addressing issues of sanitation and odor to alleviate concerns about heath department violations in the kitchens and cafeterias; An ongoing means to address any and all concerns; A “cheerleader” for the program until it becomes routine to the community; and Continuous education measures for collection from the student body.

Successful composters gain support from those paying for solid waste disposal and who generate most of the waste, know and stay within their capacity to process effectively and without odors, and have a market already established for the finished product. By Judy Purman.

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