An important marker of a material’s sustainability is its ability to break down effectively at the end of its lifespan. Can it be recycled into something new or seamlessly return back into the soil? The concept of a product leaving no trace seems ideal. However in reality, many products claiming to be compostable or biodegradable have limitations when it comes to proper disposal. In this article, we will explore what it means for a material to be labeled “degradable,” “biodegradable,” or “compostable.” What sets them apart and how should consumers responsibly dispose of these products?
“Everything is degradable…just because a product can be broken down into small pieces, does not guarantee that those small pieces will return back to nature.“
“Degradable”
Everything is degradable. That is, everything can be broken down into small pieces. However, just because a product can be broken down into small pieces, does not guarantee that those small pieces will return back to nature. Plastics are a prime example. It can take plastics hundreds of years to break down into tiny pieces. Some plastics marketed as “oxo-degradable” or “photodegradable” have additives that allow for quicker, UV-induced degradation. However, the tiny pieces that remain are microplastics-- plastic fragments that persist in our environment. They permeate the air we breathe, finding their way into our food and our bodies.
“Biodegradable”
The Federal Trade Commission came up with guidelines for the marketing of green products to help clarify terms such as “biodegradable.” While not legally binding, these guidelines establish a framework for understanding the appropriate usage of such terms.
The FTC states that an item is biodegradable if scientific evidence proves that it will “completely break down and return to nature” within one year after “customary disposal.” Biodegradable materials must be able to break down into elements such as water, carbon dioxide or biomass. An important part of this definition is the idea that the item can biodegrade after “customary disposal.” This means that if a product biodegrades in soil, but is typically discarded in landfills, it fails to meet the “biodegradable” criteria.
Many products which can biodegrade in soil cannot do the same in landfills. Due to the absence of light, water, and oxygen required for bacterial activity, these materials instead break down anaerobically, producing methane. Methane is a greenhouse gas that is 25 times more potent than carbon dioxide. While some landfills are able to capture and convert this methane into energy, biodegradable materials still remain an issue at these disposal sites.
“Compostable”
Compostable products are the gold standard of biodegradable products. According to the FTC, an item is compostable if there is evidence that it will “break down into, or otherwise become part of, usable compost” in either a home compost pile or a composting facility. The key lies in breaking down into nutrient-rich soil amendments or mulch within a comparable time frame as other composted materials. It is also important that the compost is “usable.” Some products may degrade into compost while leaching toxins, rendering the compost unusable.
Compostable materials should be appropriately discarded to take advantage of their biodegradable properties. Like all biodegradable materials, compostable materials should not be disposed of in landfills, where it will degrade anaerobically. Clear instructions on whether the product can be composted at home or in a commercial composting facility should be provided.
Commercial composting facilities are able to sustain a higher temperature than home composting. Therefore, more products may be suitable for industrial composting. According to the USDA, there are currently 4,700 industrial composting facilities in the US, each with specific processing capabilities. FindAComposter is a useful resource to help locate your nearest industrial composting facilities.
To establish and regulate compostability standards, the Biodegradable Products Institute is a reputable provider of certifications for industrially compostable products in the US. They use ASTM test standards to ensure the product will biodegrade at a similar rate to other compostable materials, resulting in a usable compost.
Bio-based does not mean biodegradable
The use of natural, organic, or bio-based materials does not automatically guarantee its biodegradability. For example, natural products such as leather have undergone chemical changes to stop the degradation process. Similarly, bio-based plastics may incorporate ingredients derived from nature. However, these ingredients may be combined with others that hinder biodegradability. As we continue to learn about what makes a product truly sustainable, it is crucial to read between the lines of eco-friendly labels and to be mindful of specific requirements for disposal.
