Compostable Plastics: Destined for Landfill?

Is compostable plastic one of the most widely misunderstood catastrophes of this decade?

Picture this: You forgot your reusable tumbler so you're enjoying an iced coffee in a clear plastic cup boldly labelled "100% Compostable, BPI Certified, Eco-Friendly". But you check San Diego Accepted Organic Items, which clearly states that compostable plastic is not an accepted item. What a waste (literally) since that cup could have been recyclable and/or made from recycled content but now it is destined for landfill.

The Contradiction: To Be or Not To Be Composted?

Like most jurisdictions, compostable and biodegradable plastics are not accepted in organic waste streams. So although we are seeing a large increase in compostable plastic hard goods and packaging, most of these items/materials are ending up in landfills. And since they contain organic matter, it will release methane when breaking down in the landfill (a gas that is 30x more harmful than carbon dioxide).

So what happened? Why is there so much contradicting information on compostable plastics? Is compostable plastic a sustainable initiative gone wrong? Who is being held accountable for these misleading claims? How do we expect consumers to recycle right if brands and even certification bodies are not responsible for the claims they make?

A Review: Why is compostable plastic such a challenge?

Limited Access

According to GreenBiz, only 27% of Americans have access to compost facilities, and just 3% to municipal programs. In Canada, 71% have municipal curbside pickup and 91% have access to a compost service.

Lack of Acceptability

Many facilities don’t accept rigid compostable plastics but do accept compostable bin liners and some will accept dog waste bags.

Certifications are not Reliable

After speaking with several local organic waste facilities, they indicated that even certified compostable plastics are not breaking down in the timeframes required by their facilities. For example, in their compost digester, whatever material/object is bigger than 8mm is filtered out. Rigid plastic was not breaking down that quickly/effectively.

The Compost is now Contaminated

Compost containing compostable plastic cannot be considered organic, which the facilities cannot sell it to certified organic farmers.

Recycling Contamination

Rigid compostable plastics often end up in the recycling stream may cause contamination issues when reprocessing the plastics.

It Hurts the Facility’s Business

Compostable plastics raise costs at facilities and provide little value, as most plastics will degrade into CO2 and water, not nutrient-rich soil (which is sold by the facility to farmers/communities).

It may be Threatening Human and Environmental Health

Depending on the type of compostable plastic it could contain harmful chemicals (such as PFAS) or create microplastics which is now entering the ecosystem and agriculture for human or animal consumption.

So, are compostable plastics a catastrophe?  

Kinda, maybe. It depends on the source, production, type, ingredients, additives, and end of life availability. There are good bioplastics and there are bad bioplastics, and sorting the good from bad is not so simple.

At this point, the infrastructure for compostable plastic is not available to most North Americans and many facilities do not accept compostable plastics simply because they do not have the capability, the cost is not worth the effort, or the claims are unreliable.

But bioplastics are evolving, organic waste facilities are enhancing, and accessibility is growing. Solutions are and will become available. Until then, be cautious in the bioplastic space; it is filled with misleading and misunderstood greenwashing claims.

Check out Beyond Plastics: Bad News About Bioplastics for more information.

There are plenty of arguments for and against bioplastics. What is your position?