To minimize waste generation, an integrated solid waste prevention strategy was conceptualized and implemented. The components were to: Exclude all materials from the system that were not easily biodegradable, reusable, or recyclable (given the local markets for materials recovery); Utilize a collection system that could easily accommodate biodegradable and recyclable materials; and Increase public familiarity with the collection system.
Food vendors and the on-campus restaurant participated by using materials that could be recycled or composted. Heavily waxed cups and bowls, plastic utensils, and other common waste materials were not allowed because of their ultimate fate as a waste product. Strategies were instituted to reduce material use, such as substituting napkins for plates and “finger foods.” Biocorp degradable bags and utensils were purchased and supplied at cost to the food vendors and other food services.
A three-stream collection method, divided into glass, compostables and noncompostables, was set up for the event. The noncompostables bins were hand sorted by volunteers, who emptied them onto a tilted table, removed the recyclable and waste fractions, and scraped the remainder (the biodegradable materials) into collection containers for composting.
Recovery stations were concentrated on the perimeter of the festival to facilitate easy collection and transport of materials to a centralized sorting location. Materials were either walked to the sorting area or collected with an electric dump vehicle. Several recovery stations at the interior of the festival were slightly harder to monitor and manage, but were considered necessary to prevent littering in those areas. The stations were regularly checked to keep contaminants out of the compost collection bins.
A waste audit was conducted to evaluate the performance of the waste prevention system. Waste stream characteristics are presented in Table 1. The primary contaminants in the biodegradable waste stream were plastics. The trash component (mostly brought from outside of the festival) was comprised of nonrecyclable plastics (wrappers, bags, straws, etc.), heavily waxed paper products, diapers, and broken vendor merchandise. Dumpsters for recyclables and compostables were clearly labeled and kept at the perimeter of the event for bulk collection. The indiscriminate disposal into those dumpsters contributed to both contaminants in the compost and recyclable materials in the waste.
The overall diversion rate of 81 percent (by weight) is encouraging, but also suggests that there is room for improvement. A great deal of time was devoted to removing contaminants from the biodegradables and removing waste from the recyclable materials. Although signs were used to direct materials into the appropriate collection bin, many people showed little concern or confusion regarding which bin to use for their unwanted materials. The lack of participation and problems posed by the implementation of a new collection system make public education critical. Future plans include posting volunteers at recovery stations to answer questions and further refinement of the materials and collection system.
Starting in 1996, the UC Davis Student Farm began working with the festival in its composting program. This year, nearly four tons of the festival waste stream were composted.
Windrows were constructed after the festival with a front-end loader using a mixture of one ton of festival residuals, one ton of straw, and three to five wet tons of manure. The windrows were approximately nine feet wide at the base and four feet tall. The pile was layered with straw on the bottom, then manure, festival organics, and more manure on top. The windrows were left in this arrangement for several days, allowing the paper products to absorb water from other materials and making them less likely to “float” out of the pile during turning, reducing the amount of clean-up.
An HCL Machine Works tow-behind, rotary drum turner with flails is used at the farm. The windrows were turned two times/week for the first three weeks, weekly for the next five, and then once every two weeks.
Moisture was maintained at about 50 percent during the composting process. When the windrows began to dry out, water was added with an irrigation system consisting of pipe and half-round micro sprinklers spaced about every five feet. When necessary, water typically was added less than 24 hours before turning to increase the uniformity of moisture in the pile. Additional water was sprayed after turning if a higher moisture content was required.
Temperatures fluctuated between 130° and 150°F during the first three months of composting, then declined. At that point, the volume of the windrow had decreased by about 50 percent. The BioCorp utensils and bags, as well as unwaxed and lightly waxed paper products, had completely degraded. Contaminants such as plastic, glass, styrofoam and dense paper products were removed by hand as they “floated” to the outside of the compost windrow. Paper products at the edge of the windrow were reincorporated as needed. Finished compost will be applied prior to the planting of fall crops in late September. By Harold Leverentz and Mark Van Horn.