Minneapolis Residential Organics: Less Than 1% contamination
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A residential organics collection program under 1%--is it possible?

The City of Minneapolis residential organics recycling program was rolled out citywide in 2016 and was recognized as USCC’s 2018 Organics Diversion Program of the Year for 2018. As of September 3, 2019, over 47.6% of eligible households (just over 51,000 households) have opted in to participate in the program.

To assess contamination in the program and evaluate what materials require additional education, Solid Waste & Recycling staff and willing volunteers perform audits of truckloads of organics annually. Every bag of organics is ripped open to identify and remove contaminants which were sorted by type (non-compostable plastic-lined paper, recyclables, and other) and weighed. Food that could have been eaten (edible food) was also removed and weighed separately.

Of the 26,660 pounds of organics sorted, 159 pounds of contamination were found for an average contamination rate of 0.68% (high: 1.03%, low 0.36%). The City’s organics processor, Specialized Environmental Technologies, says the organics from the City’s residential program is the cleanest material they receive from any residential or commercial source.

Contaminants found include:

  • Non-compostable plastic lined-paper products: hot and cold cups, to-go boxes, decorative paper plates, ice cream tubs, food wrappers
  • Recyclables: boxboard, yogurt cups, aluminum cans
  • Other contaminants: non-compostable plastic films, pouches, straws (some were in fact certified compostable), sauce packets, picture with cork backing

Actual contamination was less than reported due to wet food bits sticking to the contaminants pulled. Sorters were uncertain if the straws from a coffee shop were certified compostable so they were pulled and weighed with other contaminants. It was later verified that the straws were in fact certified compostable.

Edible food, items put in the organics that could have been eaten, was pulled to evaluate how much and what types of foods residents over purchase. A total of 794 pounds of edible food was pulled in the 2019 sorts. The most common food items found were potatoes and oranges. It is known that edible food weights are higher as not every baby potato, cherry tomato, etc. was able to be removed.

This is the third year Solid Waste & Recycling has sorted truckloads of its residential organics. Each year, the same two routes are sorted to have ongoing comparable data. The City plans to continue to sort the same two routes and two new routes each year until an overall picture of the City’s organics program is known. The information gathered will help with targeted outreach and education. You can find annual sort result summaries on Minneapolis Solid Waste & Recycling’s About Us webpage.

Kellie Kish is the Recycling Coordinator for the City of Minneapolis and serves as the Secretary of the Minnesota Composting Council, a USCC State Chapter.