Keeping up with compost
We visited our local composter, Cedar Grove, and saw up-close what happens to our food and yard waste.
We have a new appreciation for the challenges facing compost and learned some new things that we can all do to make composting work better!
Here's what we learned
Compost is a local type of recycling!
We’ve written before about what where our curbside recycling goes. Many times, bales of materials like plastic, metal, and paper go overseas to be made into new things. Compost in our area works differently as what we put in our yard and food waste bins is processed locally. At Cedar Grove, material goes through a composting process over 60 days. Locals can buy this compost by the truck or bagload, meaning that the entire end-to-end process can stay local. That’s a process we can get behind!
The type of food and yard waste that can be accepted can change based on where you live. Cities make arrangements with composters like Cedar Grove. Based on the price they pay, more or less materials can be accepted. Seattle was mentioned as a leader as they have made sure residents can place things like shredded paper and compostable food packaging in their organics bin. Our tour guide mentioned how important it is to understand what your city allows and to talk to your city if you’d like to be able to compost more material. Sometimes requests from cities can even cause a place like Cedar Grove to bring in new technology so they can take even more things!
This is much different than your backyard bin!
Not all composting is done using an industrial process like the one we saw. There is also backyard compost made by putting organics in a bin and having worms turn it into compost material. The industrial compost we saw can process more materials than your backyard, here’s how:
Cedar Grove is one of the most advanced facilities in the country. They closely monitor the mix of what they receive, grouping it into yard and food waste. When we visited, the mixture was 80% yard waste and 20% food waste. If this ratio changes too much, they add or remove material to make the chemical process most efficient, like adding wood chips if there’s too much grass!
During each phase, Cedar Grove measures oxygen content and temperature, making adjustments based on the readings. Because of all of this science, categories like compostable foodware can be processed in industrial facilities. Though as we’ll learn in the next section, taking so many different materials does come with a potential downside.
Contamination is a real problem (and getting worse!)
Contamination happens at a compost facility when categories like glass, metal, and plastic are put in our food and yard waste bins. Like recycling, this problem has been getting worse in recent years.
Cedar Grove had several steps to remove contaminants. Removing metal contamination (think nails or silverware) is the most effective and is done using magnets. Plastic and glass are more difficult and are often done manually at several steps in the composting process. Loads that are overly-contaminated are taken directly to a landfill!
Despite the many ways Cedar Grove tries to remove contaminants, small pieces of plastic can be missed and can be found in the compost we buy. Though we were told this is not harmful to plants or humans, this motivates us to do even more to reduce the amount of contamination being sent to composters like Cedar Grove.
Here's how we can reduce contamination in our compost
It can be hard to tell what is compostable for even the most dedicated among us. That’s why our tour guide gave us the general advice of ‘when in doubt, throw it out.’ We were also provided a few of the trickier materials that we will keep an eye out for so they do not contaminate our compost:
Plastic food packaging
Many local restaurants have made the switch to compostable silverware and packaging. While we like this trend, it’s often hard to know what is compostable and what is not.
Cartons
Liquids we buy like milk and juice come in paper cartons that have a lining made of plastic or metal. These liners can’t be removed during composting so these need to be cleaned and sent to recycling instead.
There, the paper mills are eventually able to separate the lining from the paper to be able to create new paper!
Produce stickers
These are usually made of plastic and commonly accompany things like vegetables or avocado skins. We should peel these off and throw them out instead of including them in compost since the stickers are so much harder to remove once composting begins.
We’re making sure we do this in our home. We're also excited to learn about compostable produce stickers under development!
