The ComPOSTer: Event Partnerships!

Good evening all,

With the Fall semester in full swing, activity at the S.C.R.A.P. Lab has been heating up. In the last month, we were busy processing an extra 579 lbs. of food scraps and compostable items from 3 major events on campus serving a combined total of around 1,750 people. They were: the First Year Pre-Rade (1,000 people), Graduate College BBQ (250 people), and the Facilities Appreciation Picnic (500 people).

A summary of the event logistics, successes, and lessons learned are below:

At all events, student EcoReps bin monitored Resource Recovery areas to encourage proper sorting and a clean stream of compostable items

  • 0.33 lbs/person  – average weight of compostable material per attendee (range from 0.25 to 0.4 lbs/attendee).
  • The majority of the material – about two-thirds – was compostable serviceware rather than food scraps.  Because of this the volume of the total material recovered was more significant than the weight. The 579 lbs. of recovered material took up the space of about 35 full, large garbage bags!
  • At large events, where attendees have freedom to move around, more material was collected at the permanent outdoor bins rather than the dedicated resource recovery tents, prompting us to shift our strategy mid-event and send more bin monitors to the tentless permanent bins
  • Expect the unexpected: there will likely be materials generated at the event that you didn’t expect to have (e.g. condiment packets brought by caterers). Make sure to inform the bin monitors on where these materials should be placed so they don’t end up in the incorrect stream.
  • Like the bamboo utensils tested earlier this year, the birch utensils also tended to only partially shred and did not compost fully (although they will eventually biodegrade)
  • The paper plates and wood based products should be loaded gradually into the composting system. Loading too many at once can jam the system so it is best to alternate or combine with food scraps when possible
  • Paper plates shouldn’t completely substitute for wood shavings as the bulking agent/carbon source (BA/CS) because they tend to lose their form and mat together under high moisture conditions. When adding one part paper plates per each food and wood bucket pair (equivalent to substituting around 15% of the BA/CS total with the paper plates), we found that the bulk density and free air space of the resulting compost increased and decreased respectively from baseline conditions, indicating a reduction in air flow potential throughout the compost pile. Next time we receive a large load of paper plates, we will reduce their contribution to closer to 10% or lower of the BA/CS.

Lastly, at the Facilities Picnic, we also promoted waste reduction and reuse efforts which should always precede any recycling/composting efforts:

  • Attendees were encouraged to bring their own cup (or were provided with a reusable one)
  • Reusable sporks were also handed out this year. Cleaning stations were provided so that attendees could reuse the sporks throughout the event and take them back for future use. If attendees didn’t want to keep their spork, there were also drop-off containers so that the sporks could be recovered for reuse (see photos below):

Weekly Data (9/13 – 10/10)

Weekly data from the last 4 weeks are below. You’ll notice that the % BA/CS was higher early on and has gradually returned to the usual range of ~33%. In the summer months we were receiving a higher than average moisture content so we needed to compensate with more carbon/wood shavings. Now that the academic year has started, the moisture content has returned to previous levels due to menu changes.

Total Food Academic/Residential Buildings Campus Center/Cafes Wood Shavings (BA/CS) % BA/CS Compost Off-Loaded GHG Emissions Saved (MTCO2-eq)
9/13 – 9/19 3,158 119 3,039 1,296 41% 3,400
9/20 – 9/26 3,433 201 3,232 1,265 37% 2,200
9/27 – 10/3 3,775 233 3,542 1,357 36% 3,600
10/4 – 10/10 3,324 182 3,142 1,055 32% 4,800
Cumulative (lbs) 136,433 3,157 133,276 44,193 32% 125,600 40

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