The Cal Poly Zero Waste Collaborative’s regional composting collector will no longer be able to compost any items other than food scraps.
Moving forward, biodegradable cups, lids, paper towels, napkins, utensils or plates will not be acceptable in compost bins. This notification has been posted on compost bins around campus.
Cal Poly uses the local compost facility Engel & Gray, which accepts only organic material. The change in acceptable items at Cal Poly is a result of what is tolerated at this facility.
Cal Poly Zero Waste Coordinator Anastasia Nicole said that Engel & Gray cannot accept most compostable items due to low tolerance contamination, which means that it is difficult to separate biodegradable waste from other trash thrown into public bins.
“We can accept compostable items to go to Engel and Gray, but because of their low tolerance for contamination, we can’t send them compost from public bins,” Nicole said. “The only public compost going to Engel & Gray is from events where bins are attended by Zero Waste Ambassadors to keep the contamination down.”
Nicole said they are continuing to expand the program.
For compost collected from the on-campus public bins, the Cal Poly Zero Waste Collaborative collects food waste only, because that is what is accepted locally in San Luis Obispo for the machinery used, according to San Luis Garbage.
The San Luis Obispo compost uses the Hitachi-Zozen anaerobic digester, a sealed, oxygen-free tank which breaks down animal and food waste to produce biogas and bio-fertilizer.
“Our biggest challenge is to educate students about what is compostable here in [San Luis Obispo], as they may be coming from areas that have compost facilities that accept more items [such as] all compostables or fewer items [such as] green waste only than what we can collect on campus and throughout [San Luis Obispo] County,” Nicole said.
The Zero Waste Collaborative is asking students to take the extra time to sort out food scraps from other compostable materials rather than dumping it all in the bin. The future implications could be beneficial to everyone, Nicole said.
“Food scraps in the digester will be used to produce local energy, and the finished product from the digester will be compost that can go back to local farms to produce more food and sequester more carbon in the soil,” Nicole said. “The program is definitely a win-win.”