Last week, the Custodial Waste Busters Committee hit the road again to discover where Carleton’s waste goes once it leaves campus and how it’s handled. Our first stop was at Tennis Sanitation, a local recycling company based up in the Cities. For most of us, the greatest surprise was how much hand-sorting takes place to segregate each material for processing at different facilities. First, recycling loads are dumped on the concrete floor of the building; big, hard plastics and cardboard are pulled out by hand, then a skid loader pushes the jumble of recyclables onto a conveyor belt. From there, workers pull household metals, plastic bags (bundled together in large balls), paper, and plastics of various from the conveyor belt. Tin and aluminum cans get pulled from the line by magnets. It was incredible to see how many items have recycling potential and a reminder that many people will interact with our waste once it leaves our hands. As a courtesy to these workers, remember to remove excessive liquids and rinse food (especially dairy) from your recyclables when possible.
From the Tennis Sanitation recycling facility, the Custodial Waste Busters headed south to the Mulch Store’s Empire Site in Rosemount, the facility where Carleton’s compost is processed. Each year this site handles 15,000 tons of organic waste, the majority of which is generated from commercial sources like Target but a vast quantity of which comes from higher education institutions. After being dumped at the site, organics (food waste, pizza boxes, paper towels, etc) are mixed in a 3:2 ratio with yard waste. The mixture (1200 cubic yards or 1200 pickup truck loads!) is then spread over a 6” PVC pipe to form a windrow. From the PVC pipe, air is blown through each windrow to facilitate aerobic decomposition. After about two months on the windrow and another 1-2 months in a curing pile, decomposition is complete and remaining contaminants like plastic bottles or silverware are screened out. The compost then rests for several more months and is ready for sale (or to be donated back to the Carleton Farm!) in less than one year. The Custodial Waste Busters Committee was impressed by the speed and efficacy of the composting process and hope that we can continue to divert more of our compostable waste from the landfill!
Be on the lookout for future waste tours, or check out this video featuring the processing sites of Carleton’s three main waste streams.
For more information about the Custodial Waste Busters, click here!