Imagine you’re finishing dinner at a local restaurant and have some extra food. Responsibly, you take your leftovers home in a compostable take-out container provided by the business. Like many sustainably-minded consumers (and the restaurants that provide them), you feel good about choosing a compostable option. But what happens next? The journey of that compostable container is more complex and can be less sustainable than you may think.
After you finish your meal at home, you toss the empty container into your compost bin, believing it will break down naturally. However, in many areas, especially those lacking access to industrial composting facilities, this is not the case.
Most compostable plastics are designed to break down under specific conditions found only in industrial composting facilities because these materials are engineered to decompose quickly and efficiently in a controlled environment (and so they can maintain their integrity while holding food, preventing them from breaking down too quickly during use). Industrial composting facilities maintain high temperatures, often between 140-160°F (60-70°C), which accelerate the breakdown process. They also ensure optimal moisture levels and consistent aeration, which are critical for the microbes that decompose organic matter to thrive. These conditions are difficult to replicate in home compost bins, which generally do not reach the necessary temperatures or maintain the consistent environment needed for effective decomposition. As a result, compostable plastics in home compost bins may not break down as intended, leading to prolonged persistence in the environment. This discrepancy underscores the need for improved access to industrial composting infrastructure to ensure that compostable plastics fulfill their environmental promise.
According to BioCycle, in 2023, 14.9 million U.S. households had access to food waste collection programs. This represents just a mere 4% of all U.S. households. Yet, compostable plastics are sold in all 50 states and throughout U.S. territories.
Without industrial composting infrastructure, your compostable take-out container likely ends up in a landfill. Landfills do not provide the high temperatures, consistent moisture levels, or controlled aeration required for compostable plastics to break down efficiently. In a landfill, the conditions are anaerobic, meaning there is little to no oxygen, which significantly slows down the decomposition process.
As a result, compostable plastics that end up in landfills decompose very slowly, if at all. Instead of breaking down into harmless organic matter as they would in an industrial composting facility, they persist for long periods in a landfill. During this slow decomposition, they can release methane, a potent greenhouse gas that is significantly more effective at trapping heat in the atmosphere than carbon dioxide. This contributes to global warming and climate change, negating the environmental benefits that compostable plastics are supposed to provide. This outcome is far from the environmentally friendly solution you intended when packing up your leftover food in that compostable container.
A lack of proper composting infrastructure transforms what is intended to be a sustainable solution into an environmental hazard. This underscores the importance of having access to industrial composting facilities capable of processing these materials correctly and highlights the need for better waste management practices and infrastructure.
Even in regions with industrial composting facilities, the system is not foolproof. Many compostable items are mistakenly sorted with regular plastics, contaminating recycling streams and complicating the waste management process. Moreover, the market for recycled compostable plastic is limited. Virgin plastics, especially those produced overseas, are often much cheaper and more appealing to manufacturers.
This issue highlights a critical point: relying solely on waste management systems, whether for recycling or composting, is not enough. We must take proactive steps to reduce waste at the source. Opt for reusable containers and utensils whenever possible. Support local businesses that prioritize sustainability and pressure local governments to improve composting infrastructure.
Understanding the challenges of compostable plastics is crucial. Without the necessary facilities to process these materials, even the best intentions can lead to negative environmental impacts. By focusing on reducing waste and improving composting access and affordability, you can make a more significant and positive impact on the planet.