Understanding "compostable" disposables

With the recent changes to plastic recycling you may be searching for more sustainable alternatives to things like plastic cups, take-out containers, straws, coffee cups, and more that are now finding their way to the landfill. Many of have pointed to compostable or biodegradable plastics as a possible solution. But are these supposedly green alternatives, a viable solution when used here in Flagstaff?

The answer to that question is a nuanced one, but ultimately at this point in time, using compostable or biodegradable plastics offers marginal benefits, if any, to their disposable alternatives. Currently there are multiple barriers preventing them from being a viable alternative to standard plastic disposables. 

Where to compost?

The biggest obstacle to utilizing these compostable and biodegrable options is a lack of facilities that can compost them. Just because they are labeled compostable does not mean that they will break down in any compost pile, and certainly not your backyard pile. These products are designed to breakdown in a "controlled composting environment," which means that they need an industrial facility that reaches temperatures higher than 140 degrees. This type of facility does not exist in Northern Arizona, at least not yet. If you've ever tried to compost these types of items in your backyard compost, you might find something similar to the picture below leftover after all other material has decomposed. 


Some might argue that even though these products can't be composted here in Flagstaff, they are still better than standard plastic because they will break down faster if they end up in the landfill or our environment. This also is not the case. Because these products require such a specific set of circumstances to decompose, they do not break down quickly in a landfill where there is no light, oxygen or microbes to help with decomposition. They also do not solve the problem with plastic pollution in the ocean, as oceans do not provide the appropriate temperatures needed for their decomposition either.

Upstream impacts

Even when looking at the upstream impacts of these compostable products, it is debatable whether they provide a significant upside over their oil-based alternatives. Compostable, or bio-plastics, are typically made from corn, which is produced in a resource intensive manner utilizing heavy machinery, fertilizers, and pesticides. All of these inputs require oil, making it difficult to argue that bio-plastics foster less dependence on petroleum than the standard oil-based plastics. 

Consumer confusion

As you can see there are many caveats associated with these types of products, which leaves much room for confusion on the part of consumers. Depending on how compostable products are marketed or labeled, consumers may be unsure of how to actually dispose of them. Because they often are misconstrued for standard plastics, they often end up in the recycling stream where they can contaminate loads of recyclable plastic. 

How to be a better consumer?

While compostable and biodegradable plastics do not provide us with a very obvious solution to our plastic problem in Flagstaff (at least not right now), there are still very clear ways to reduce the amount of plastic heading to the landfill and your environmental footprint. As we have always stressed, the best thing to do is reduce and reuse. Whether it is a reusable water bottle, coffee mug, grocery bag, or even take-out container, avoid single-use products entirely by bringing your own durable alternatives. 

There are other things you can do to minimize the impacts of these products, including:

  • Watch for containers and bags labeled “compostable”, “biodegradable”. They will often be labeled with a #7.

  • Keep these containers out of your recycling bin. Mixing the these bio-plastics with standard plastics together causes problems for petroleum plastics recycling.

  • Keep them out of compost containers as well. They won't break down in your backyard compost pile and it is costly for the local composting operations that do exist to remove them.

  • Purchase locally made foods or grow your own to avoid the need for packaging for transportation and storage.