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Public Composting Pilot

pilot food scrap cart with big belly trash and recycle
UPDATE 10/15/19: The pilot has been concluded due to ongoing contamination.
In fall 2019, Kirkland ran a four-week pilot program to evaluate the viability of public food composting in Kirkland.

Why We Offered a Pilot Program
The pilot was proposed by four students from Kirkland who are part of the student-run group The Tomorrow Projectlinks to external site. Their current primary focus is keeping food out of the landfill, and their goal is inspiring sustainable practices in the community and making it the norm for people to live sustainably. The students met with staff, prepared a proposal, and committed to monitor the cart during the pilot period and prepare a report summarizing the results.

Composting food instead of throwing it away is environmentally beneficiallinks to external site. Compost returns nutrients to the soil in home gardens and agriculture, sequesters carbon, and helps filter pollutants in stormwater projects. In comparison, food that is thrown away sits in the landfill and produces the greenhouse gas methane as it slowly decomposes over the course of many years.

Challenges of Public Composting
The cart is designated food-only in an attempt to minimize plastic being placed in the cart. Some restaurants in downtown Kirkland provide compostable food packaging and beverage cups, while others use recyclable or disposable products, and it can be challenging to distinguish them. Plastic and glass present a major challenge for composting because they cannot be removed during processing and reduce the quality of the final compost. Even a single glass bottle can cause significant harm because it breaks into tiny pieces that spread through many yards of compost.

The City offers public recycling receptacles in downtown Kirkland and at neighborhood parks, but has not offered public compost containers before. Unfortunately, many of the public recycling bins are often contaminated with garbage and non-recyclable items such as food, dirty beverage containers, and pet waste. Heavily contaminated loads must be disposed as garbage. Likewise, if the public food scrap cart contains significant quantities of garbage, the material will need to be thrown away.

Pilot Program Evaluation
The students monitored the cart over a month period to evaluate usage and identify whether the correct items were being placed in it.
students with public compost cart
Pictured: Maxwell Feldman, Neha Gupta, Surbhi Jain, and Tallie Voss from The Tomorrow Projectlinks to external site

Program Results
Note: photos taken by student volunteers on Thursday and carts are collected on Friday morning, so there may be additional contamination put in the cart after the photo is taken.

September 19, 2019 - first week
Photo of contents of public compost cart

Food: orange peel, banana peels
Compostable packaging: compostable bag (presumably with food scraps)
Contamination: sticker on fruit
Hauler marked cart as contaminated on 9/20 - dumped as garbage

September 26, 2019 - second week
Photo of contents of public compost cart

Food: banana peel, apple core, ice cream cone
Compostable packaging: fiber gelato cups, wooden gelato spoons, paper napkins
Contamination (non-compostable items): plastic bottle, candy wrappers, box with sticker, foil, paper brochure
Hauler marked cart as contaminated on 9/27 - dumped as garbage

October 3, 2019 - third week
Photo of contents of public compost cart
Food: banana peels, waffle, ice cream cone
Compostable packaging: fiber gelato cup, paper napkins, compostable cups with lids
Contamination (non-compostable items): lined takeout box, plastic utensils, non-compostable coffee cup with plastic lid
Hauler marked cart as contaminated on 10/4 - dumped as garbage

October 10, 2019 - fourth week
Photo of contents of public compost cart
Food: banana peels, rice krispy treat, ice cream cone
Compostable packaging: fiber gelato cup, paper napkins, paper bags, wooden gelato spoon, paper coffee sleeves
Contamination (non-compostable items): non-compostable coffee cup with plastic lids/straws, tea bags (many tea bags include plastic content, which these appear to be), gum wrapper
Unclear: takeout bowl appears to be compostable fiber but lid, fork, and condiment cup are not clearly identifiable from photo
Hauler marked cart as contaminated on 10/11 - dumped as garbage

October 15, 2019 - pilot halted due to ongoing contamination.
The public food scrap cart has been removed from Park Lane. For all four weeks of the pilot, the cart was too contaminated to be composted, and was required to be dumped as garbage. The team will assess lessons learned and brainstorm other possible approaches to test. Public composting is very challenging to implement because a single person who does not follow the guidelines can contaminate the entire cart.

Public Works
123 5th Avenue, Kirkland WA 98033
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