compostable and biodegradable…plastics?
As a consumer, you may have eaten take out with single-use cutlery that looked and felt like plastic, yet stated it was “biodegradable” or “compostable.” If I could guess, it probably had a cute, little leaf next to it.
The feedstocks of such “bio-based” plastics are renewable and can be grown again and again (e.g. sugarcane, corn, potatoes, wood cellulose).
The current upstream impact here is generally net-positive compared to conventional plastics with a non-renewable petroleum feedstock.
makes you feel good, right?
Eh, not quite when considering the downstream impact. These types of bioplastics only biodegrade in the right conditions provided largely by industrial composting facilities. Exposure to UV light, moisture and high temperatures all need to be strictly regulated for these materials to successfully break down.
For context, there are only about 200 industrial composting facilities in the US that guarantee such conditions. These serve less than 5% of the US population. (1)
On top of such stark statistics, most composters do not accept bioplastics because they don’t produce “good” compost and are viewed as contaminants.
Here’s an excerpt from The Future of Packaging‘s Mike Manna, Founder and Managing Director of Organic Recycling Solutions,
“If you have a choice between a sandwich filled with veggies and all other sorts of yummy things, or a piece of cardboard, which would you eat? For a composter, a sandwich is a nutrient rich food waste like coffee grounds and yard trimmings and cardboard is the bioplastic.”
Can I toss the bioplastic into the recycling bin if my city doesn’t offer composting?
Most bioplastics are typically categorized as “other” plastics #7 and are generally not municipally recyclable. (1) In fact, they are largely considered a contaminant to recyclable plastic streams. Many of these bioplastics look just like petroleum-based plastics, causing consumers to mistakenly place them into their recycling bins which causes problems at the MRF (Materials Recovery Facility).
When tainted, these bales go straight to landfill. (1)
Can I get some good news?
Mainstream recycling is do-able with today’s infrastructure if the plastic is made from both conventional PET and bio-plastic (bPET). (1) Slowly but surely, this reduces our reliance on fossil fuels here while still achieving attempt for mainstream reuse. This keeps material inputs and energy in the production cycle longer. For example, Coca-cola launched the first iteration of their PlantBottle a few years ago which held 30 percent ethanol sourced from plant material (70% remaining was petroleum) and could be recycled with traditional PET containers and bottles. (1)
Has anyone cracked this code?
Coca-cola recently unveiled the newest iteration of their PlantBottle last month. It leverages patented technology that converts sugarcane and the crop’s manufacturing waste which creates the inputs needed for making PET plastic bottles. According to Packworld, “The packaging looks, functions, and recycles like traditional PET but has a lighter footprint on the planet and its resources.”
Are bio-based plastics our long-term solution?
While the newest PlantBottle iteration proves that there are promising prototypes, industry must also consider the agricultural capacity needed to pull this off over the next 10-15 years.
Mike Manna states that, “offsetting demand for petroleum-derived bioplastics would call for millions of additional acres of agricultural space,” and we’ve already reached our limit A) indirectly growing crops to feed the animals to feed our population and B) growing the crops to directly feed our population.
To ensure that we are on a positive path with the least amount of environmental trade-offs, R&D teams must leverage agricultural waste for bioplastic feedstocks, and produce the bioplastic to be identical to PET to ensure recyclability within our current US infrastructure.
Source (1); The Future of Packaging. Tom Szaky. Chapter Written by Mike Manna. Pages 105-111. Published in 2019.