Bringing Food Waste Composting
to UT Austin

Meagan Jones
Environmental Specialist
Division of Housing and Food Service
mjones@austin.utexas.edu

photo of recycling station

In October 2010, the University implemented its first food waste composting program, representing a major step forward in meeting the University’s sustainability and waste reduction goals. This initiative is the product of over two years of research and planning initiated by the Division of Housing and Food Service (DHFS), including researching composting programs at other institutions, exploring possible University and community partnerships, transitioning to compostable service ware, and finally working with Texas Disposal Systems (TDS) to commercially compost all food waste and compostable materials from DHFS dining locations.

The Search for the Right Process

We researched many composting techniques as we worked toward our goal of a division-wide composting program. Research was primarily conducted online through sustainability related listservs and at conference sessions. The results were very broad, as each university had tailored their program to their specific size and needs. Many colleges and universities with agricultural programs were already maintaining a compost operation for their animal waste and bedding and were able to expand upon this program by adding their food waste. Some smaller universities were able to use on-site composting containers such as the Earth Tub1 for batch processing and others were working with local farmers. Due to UT’s size and geographic location, our leading options included maintaining a large in-vessel composting unit on the campus, windrow composting at Pickle Research Campus, giving our food waste to local farmers, and commercial composting.

In-vessel composting. In-vessel composting units are pieces of equipment designed to compost materials in an enclosed environment. You can compost in this method with either a batch process or continuous process. The continuous process allows you to continually add food waste to one end and harvest from the opposite end. Rotation and aeration are required, as well as a healthy balance of carbon and nitrogen sources to produce a compost product after a specified time period. After removal from the machine, a space- intensive curing period is needed to turn the product into useable compost.

photo of food items for composting

Windrow composting. Windrow composting produces compost by piling compostable materials in a long row. The rows are periodically turned and monitored to maintain high heat in the pile. Heavy equipment and a large amount of space are needed to compost in this style. The potential for a large-scale, windrow composting program at the Pickle campus was briefly explored but proved difficult due to the extensive regulation and permitting process, equipment and staffing needs, and the conclusion that waste management was beyond the scope of our organization.

Giving food waste to farmers. A food waste dehydrator was tested briefly in Kinsolving Dining Hall to determine the feasibility of dehydrating our food waste to then give to local farmers to add to their compost piles. After using the batch-based product for a few months and contacting the potential recipients, we determined that this type of equipment would not suit our needs. The energy required to dehydrate the food, the need for multiple units across campus, and the lack of interest from local farmers ended the test run of this equipment.

Commercial composting. Finally, we determined that working with a commercial facility would be the most feasible solution for DHFS and the process began to find a suitable company. After a competitive bid process, DHFS chose TDS to handle all compostable waste from DHFS facilities. Service with TDS commenced in October 2010.

Implementation of Composting Program on the UT Campus

photo of restaurant recycling station

Service Ware and Equipment Needs. For a successful composting program in the retail dining locations (Jester City Limits, Littlefield Patio Café, and Cypress Bend Café) alternatives to traditional disposable service ware items such as wax coated cups, plastic ware, plastic salad containers and straws were needed. This transition began slowly in 2008 and proved to be challenging at times. Items such as bagasse (a crushed sugarcane product) plates and bowls and PLA (corn) cups were easily identified as compostable alternatives for use in our dining locations, but items such as small compostable bowls, flatware, and some sandwich containers posed a problem. As the compostable service ware industry has expanded over the last few years, we have been able to identify compostable replacements for approximately 95% of our disposable items.

The most challenging piece to identify proved to be the flatware. Flatware made of cornstarch is sturdy in cold temperatures but has a very low melting point, while flatware made of potato starch has a much higher melting point but is more flexible at all temperatures. After over a year of potato starch ware, we decided to return to reusable, metal flatware in all retail dining locations. This solved the problem of unsatisfactory cutlery as well as decreasing the overall waste generation. Reusable service ware is used in the all-you-care-to-eat facilities, Kinsolving Dining Hall, and J2 Dining Hall, so there were only a few changes required, including PLA straws.

Compost Sorting. To facilitate the necessary sorting of trash, compost, and recycling in the retail dining areas, custom sorting stations were designed with color-coded signage and restrictive openings. We found that our customers are more comfortable with the sorting process when they are able to match the items they have with the items on the sign. These specific bins were also chosen due to the fact that there were constructed from recycled milk jugs.

For post-consumer sorting in Kinsolving and J2 Dining Halls, as well as pre-consumer sorting in all kitchens, no customer involvement is needed. As food is returned to the dish room through the plate returns, plates are rinsed through a trough of water that sends the food waste, napkins, and compostable straws into a pulping machine. Inside the pulper, the food becomes finely chopped and water is extracted as it travels up the auger and into a red bin that is designated for compostable items. Kitchen prep areas are also equipped with compost bins and staff members are trained to put all food scraps and other compostable items in these bins.

Compaction, Delivery, and Reuse. Once the compostable waste is removed from our dining locations in compostable bags, it is placed in one of two compost compactors located near our dining facilities. DFHS staff notifies TDS when a compactor is full and TDS delivers the material to their composting facility. Once at the facility the compostable material is placed in long windrows and maintained for 45 days before it is screened, mixed, and sold at GardenVille, a gardening store maintained by TDS.

Educational Benefits. Through the implementation of the composting program, many students have been taught about the benefits of composting and how they can decrease their environmental impact through this type of waste diversion. Students are learning this by merely dining in DHFS dining locations or through attending other outreach events such as the sustainable dining tours conducted in conjunction with academics. The hope is that this program will not only decrease a student’s environmental impact while on campus but that they will take this knowledge and apply it after they leave the University.

photo of compost pile

Results and Future Plans

During the 2010–11 academic year, the DHFS composting program diverted 118 tons or 8% of our total waste stream from the landfill. We have successfully kept the contamination rate below 10% through the use of the customized sorting stations, through customer and staff education, and by replacing landfill-bound plastic ware with compostable and reusable materials as much as possible in the retail dining areas. Contamination is considered to be anything that is not compostable such as rubber gloves, foil, candy wrappers, etc., and can disrupt the composting process by requiring screening and ultimately decreasing the value of the end product.

Future plans involve expanding the composting program to DHFS administrative offices and break rooms, and eventually into the residential areas. As the program evolves, we hope to divert a much greater %age of our waste from the landfill and to set an example for other food service providers on the campus.

References

  1. “Earth Tub,” http://www.compostingtechnology.com/invesselsystems/earthtub/.