A joint University of Michigan (U-M) and City of Ann Arbor food waste collection and composting pilot project began in July 1997. The pilot project will allow the U-M to explore the collection of source-separated food wastes and allow the City to test the addition of food wastes to their municipal yard waste composting operation.


Applicable Regulations
State of Michigan Act 451 Part 115.


Overview of Procedure
The City of Ann Arbor Solid Waste Department (City) and U-M Grounds & Waste Management Services are conducting a food waste collection and composting pilot program that began in July 1997. (Composting is a process by which organic wastes are degraded by microorganisms, typically at elevated temperatures. Typical compost temperatures are in the range of 50 to 55 degrees Celsius. The increased temperatures result from heat produced by microorganisms during the degradation of the organic material in the waste). Vegetative, pre-consumer ("prep") food waste will be collected from U-M dining service kitchens and transported to the City's composting site for processing and composting.

The U-M will be responsible for collection, including: training kitchen staff, procuring suitable collection carts, testing different collection methods, types of vehicles (i.e., rear load; flat bed), and recording qualitative and quantitative information about food waste and delivering waste to the composting site.

The City will handle composting operations at the site of the Ann Arbor landfill, including: managing windrows (compost is placed in long piles known as "windrows" and periodically mixed using mobile equipment), turning piles, providing appropriate bulking agents (i.e., wood chips), testing the mix of food waste and bulking agents, monitoring windrow conditions, moisture, temperature, and odor, and testing the final product.


Waste Minimization Procedure
The following is a description of the activities and tasks that have been established to ensure the successful implementation of the pilot project.

Start up: U-M Grounds & Waste Management Services staff will prepare and conduct training sessions for staff in the U-M dining area facilities. Waste Management staff will meet regularly with Dining Services personnel to monitor the impact of the program on their daily operations. Several styles of wheeled collection carts will be utilized. Each kitchen will be visited to determine the location of carts, temporary storage, and a collection schedule. At the composting site, the City will be testing the water quality of the adjacent pond, which currently collects runoff from the composting site. Voluntary before and after testing will take place to monitor compost site runoff to ensure that the composting operation does not have an adverse impact on the pond.

Collection: As kitchen personnel prepare meals, food scraps such as fruit, vegetable peelings, lettuce leaves and egg shells will be placed in carts. U-M Grounds & Waste Management Services will collect food waste three times per week, swapping empty carts for full ones using a flatbed truck. Regular monitoring and feedback regarding quality control will take place. Any contaminants found will be reported back to kitchen operations.

Composting Operations: The food waste will be delivered to the Ann Arbor composting site. The truck will be weighed prior to tipping. Windrows will be formed, starting with a layer of 6 - 8" of wood chips. Site personnel will use front-end loaders to arrange windrows. If deemed necessary, all food waste will first be ground in a tub grinder and mixed with wood chips or other yard waste. Windrows will be frequently turned to maintain aerobic conditions. On a daily basis, readings of temperature, moisture, oxygen, etc., will be taken and recorded.

Closure: When the composting cycle is complete, the finished product will be tested for quality and growth trials will be conducted. Photo, video, and written documentation will be compiled and presented in a final summary report.


Known Limitations
If plastic bags are used, they cause numerous problems at the composting site because the bags must be manually broken open. Furthermore, the City of Ann Arbor local ordinance prohibits use of plastic bags for organic wastes delivered to the composting facility.

Only vegetative food wastes separated at the source will be included, although soiled napkin waste may be added later. Meat and meat products, dairy foods, fats, oils, and grease do not readily break down in composting piles and may cause undesirable odors and increased chance of disease carrying organisms. Training of kitchen staff in this area is very important to avoid contamination.


Safety & Health Precautions/Personal Protective Equipment
Follow all applicable safety and health protocols and regulations as established by your institution.


The main benefit to implementing the program is the potential impact it has on the waste stream. Since food waste is a heavy, dense material, it will help lower the cost of trash disposal in areas where waste is paid for by weight (i.e., ton). Washtenaw County estimates that food waste accounts for as much as 18.3 percent of the total solid waste stream. U-M estimates that it will handle between 12 tons (May - August) and 52 tons (September - December) of food waste during the project timeline.

In addition to the benefit of diverting waste from the landfill, the project will produce a usable, finished product: compost.


Collection of food scraps and waste will require additional labor and route time, above the regular solid waste, paper recycling, and containers recycling routes. It is uncertain at this time if separation requires extra labor in the kitchen operation, (i.e., cleaning of carts). Some additional labor may be expended at the City of Ann Arbor Composting Site for processing and screening.


Project Related Costs
The U-M estimates that the one year pilot project will cost approximately $27,000. Almost $17,000 would be University expenditures, including:

  • Labor:

- Project management and training;
- Source separated collection;
- Travel to site/weighing/dumping;
- Cleaning and washing tip carts;

  • Purchase of tip carts;
  • Printed training materials and signs for kitchen;
  • Student intern;
  • Kraft bags;
  • Project publication development;
  • Magnetic "Food Waste" truck sign;
  • Photographic slides and videotape.

The remaining $10,000 in project costs would be absorbed by the City of Ann Arbor for:

  • Testing pond water/runoff;
  • Testing finished compost;
  • Purchase of signs to mark windrows;
  • Purchase of oxygen test meter;
  • Labor:

- Processing (grinding, turning, site);
- Project management/site tours;

  • Student intern.

In 1996, the unit cost of solid waste (collection and disposal) was $98/ton. If the projected 12 tons (May - August) and 52 tons (September -December) of food waste are diverted from the waste stream, the U-M will save between $1,176 and $5,096 in solid waste disposal costs during the pilot project.

The cost of continuing the program, if successful, would decrease in subsequent years as collection efficiency increases. Also, many of the start-up costs such as personnel time involved for training of employees, purchase of tip carts, training materials, and signs would be a one-time expenditure.