Why compostables and bioplastics aren’t the answer
Bioplastics and compostable packaging are often presented as “green” substitutes to single-use plastic. Consumers and businesses buy into the narrative because they want to do the right thing.
But unfortunately, compostables and bioplastics tend to be no better for the environment in practice, and are most often simply a regrettable substitution.
The brown fiber takeout box and the bioplastic fork seem better for the environment than single-use plastic — after all, they say “compostable” — but in reality they are trading off environmental harms. Products like paper to-go boxes and bioplastic cutlery require more energy, water, and toxic chemicals to produce than even single-use plastics. What’s more, organic materials in landfills produce the highly potent greenhouse gas methane, so without commercial composting facilities, the end of life for these products is bad news for the climate.
The real problem isn’t just single-use plastic, it’s single-use itself.
Definitions: biodegradable vs. compostable
“Biodegradable”
Materials that can ultimately decompose with the help of bacteria and fungi and turn into water, carbon dioxide, and biomass as a result. Biodegradation is a process that occurs without human interference and within no specific time frame. Compostables, and especially bioplastics, that end up in the environment may or may not biodegrade.
“Compostable”
Composting, on the other hand, is “human-controlled degradation.” Items that are compostable are also biodegradable, but they break down in a much shorter time frame determined by the composting facility — usually around 80 days. One purpose of composting is to produce nutrient-rich soil for agricultural production. Fiber-based and bioplastic containers have very little to no nutrient value when broken down.
Debunking the compostable foodware and packaging myth
Compostable foodware and packaging can be made of bioplastic, paper, and plant-based fibers. Many bioplastic compostable products are made from PLA, which is usually derived from corn or sugarcane. Most compostable plastic cold cups and cutlery are made from PLA.
Compostables have a heavier environmental toll than other single-use products across numerous measures — including global warming impact, land occupation, eco- and human toxicity, and aquatic impacts.
It doesn’t matter whether the compostable product is composted, landfilled, or incinerated. This is typically because most foodware and packaging marketed as compostable is produced with agriculturally derived feedstock (sugarcane, corn, potatoes, etc.) that requires extensive use of fossil fuels related to pesticides, fertilizers, and farming equipment. The final act of composting the package does not offset the impacts of the fossil fuel inputs. In some cases, recycling, incinerating or landfilling compostable foodware may even be preferable to composting it.
Greenhouse Gas Emissions are higher.
In addition to the fossil fuel inputs to grow and manufacture the materials, compostable packaging products that end up in landfills release methane, a greenhouse gas that traps more heat than carbon dioxide by thirty-fold.
Ecotoxicity is a concern.
Growing crops for biomaterials can increase acid rain, contaminate soil and water resources with fertilizers and pesticides, and cause nutrient overloads (dead zones) in waterways. The water consumption in the growing phase of bio-based plastics also makes them a less favorable choice among single-use options.
Molded fiber compostables often contain toxic PFAS.
Many so-called compostables that look and feel like natural fibers molded together are made with toxic chemicals like PFAS to make them waterproof. These “forever” chemicals are linked to harmful health impacts in adults and children, and communities are finding PFAS in their compost piles from compostable foodware that was mixed in.
Many compost facilities don’t want compostable plastics, and many don’t accept any compostable foodware or packaging, because of the contamination it causes.
Contamination is a huge problem for composting facilities, and much of the equipment they buy is specifically designed for removing contaminants. When compostable packaging is accepted, non-compostable “look-alike” plastic packaging also enters the compost stream.
Moreover, much compostable foodware and packaging does not function as intended in compost facilities because currently marketed products, particularly compostable bioplastic, do not degrade within the 60-90 days required by commercial composters. Unfortunately, the sorting equipment (and the removal of the contaminants) also causes problems, often pulling good organic matter along with the contaminants, which then gets sent to landfills, where it produces climate-warming methane.
Further, while compostable plastics are not the biggest contamination source in the compost stream, many composting companies want their soil product to be certified as organic because it’s a better, more profitable product. However, they cannot receive Organic Certification if they process bioplastics, because the highly processed packaging is considered synthetic.
Fiber-based compostable packaging is practicably compostable in commercial compost facilities (but often not at home) and is not considered a contaminant. However, unlike food waste and yard trimmings, fiber-based compostable packaging does not add valuable nutrients to compost and is recommended to only be a small mix of the total makeup of commercial compost. Most fiber-based packaging is also recyclable, and recycling it has a lower environmental impact than commercially composting it.
The total GHG impact of landfilling 1000 compostable containers per day for a year is 26.02 Metric Tons of CO2. Add water usage and the total impact comes to 57 MTCO2 — on par with plastic.
How Much Methane Comes out of Compostable Containers in a Landfill?
The bottom line.
Reusable foodware and packaging is always the best choice if you are looking for a better alternative to single-use plastic. Understandably, it may seem easier to switch from one kind of single-use to another, rather than redesigning your whole system, and reusable options may not be possible in every use case. Therefore, it’s important that if you choose to go compostable, you do so fully informed. We recommend turning to BPI (the third-party certification organization for compostable products) for the most practicable option for your given situation.
Resource Library
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Compostable Cups Are Great, but the US Has No Place to Compost Them
Food & Wine
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Will Reusable Packaging Capitalize on Current Troubles with Compostable Packaging?
Packaging Digest
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Demystifying Compostable and Biodegradable Plastics
Beyond Plastics
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Why Oregon Composters Don't Want "Compostable" Packaging
Oregon DEQ
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Oregon Department of Environmental Quality Report
Oregon DEQ
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Compostable food containers could release PFAS into environment
Science Daily
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Bioplastics: sustainable solution or distraction from the plastic waste crisis?
Environmental Health News