What is the difference between Compostable and Biodegradable?Updated a year ago

Thank you for looking for more information on this question! Here's a definition of three terms in this space, often incorrectly used interchangeably:

Compostable: This term refers to items that microbes can break down at a rate consistent with other compostable materials, with the right level of heat, water, and oxygen. An important aspect of being considered compostable is that an item breaks down over a reasonable period (a week to several months). Composted items should leave no discernible residue or toxins, resulting in a nutritive soil amendment.

Biodegradable: All compostable items are considered biodegradable, but not all are compostable. Biodegradable packaging means it can degrade from the action of naturally occurring microorganisms such as bacteria, fungi, and algae. In and of itself, the term biodegradable makes no claims as to the amount of time needed for degradation or the attributes of the end product. Something can biodegrade but take years and would not be compostable. Other things can biodegrade but leave behind high levels of toxins, contaminants, and chemicals and are therefore not compostable. Other items might biodegrade but not do so in a compost environment and are therefore not compostable.

Degradable: Degradable is a term that can be applied to anything that breaks down. These days, the term degradable often refers to “oxo-biodegradable” or traditional plastic material treated with an additive that will break down on an accelerated timeline with the right combination of sunlight (UV), heat, and/or mechanical stress. The end product of oxo-biodegradable could be tiny fragments of the original item instead of biomass (the result of composting). These tiny fragments could be biodegraded in some cases if they went into a second, highly controlled degradation phase.

If you're asking this question, you may wonder if biodegradable offers the same (or at least similar) benefits as compostable materials. Here's the scoop:

• Biodegradability is a vague term that doesn’t necessarily tell you much about how to dispose of something.
  • Items that are naturally biodegradable (like paper, hemp, cotton, etc.) are compostable (backyard and industrial)
  • Synthetic items that claim to be biodegradable are typically made with bioplastic. These packaging items MUST have guidance and certification on how they should be disposed of – either recycled or composted – typically in an industrial facility (and certified as compostable). Without this guidance, these items should be landfilled. Unfortunately, bioplastic is one of the biggest contaminants in industrial composting and recycling facilities.

• Nothing biodegrades in a landfill! Whether it is biodegradable, oxo-biodegradable, or compostable, it will not degrade in any accelerated way in a landfill.
• Degradable / oxo-biodegradable is NOT a solution to litter or ocean pollution. The Sustainable Packaging Coalition is very anti-oxo-biodegradability (preferring traditional plastic) because tiny plastic fragments in the ocean are more harmful than larger bits of plastic.

In case you're looking for some more prescriptive guidance on the question of whether or not you should look for biodegradable or compostable packaging for your eCommerce business, here's our point of view in a snapshot:

• Biodegradability as a characteristic is most important when it relates to packaging with some reasonable chance of becoming litter – candy bar wrappers, straws, and plastic grocery bags. These items become litter (1) because they are consumed on the go and/or (2) they are so light that they can easily be picked up by the wind and blown away.
• Compostable bioplastic can also be an excellent solution in the food world. It's great for “to go” food packaging (like EcoProducts items) that need a liquid-proof liner. Compostable packaging encourages food waste to be composted – a GREAT end-of-life scenario for food.
• We are not advocates of most plastic "biodegradable" packaging options as a solution for eCommerce shipments. They are almost always 100% virgin material, leading consumers to dispose of them badly (i.e., people landfill them thinking the packaging will "go away" quickly), they are recycled and contaminate the recycling stream, or they are composted and aren't certified as compostable. Even worse, often, they are oxo-biodegradable. We advise companies looking into biodegradable plastic packaging to ask lots of questions to ensure they know what they are getting so they can accurately advise their customers how to dispose of something.
• We typically direct companies looking for biodegradable packaging to seek out naturally biodegradable options, such as paper mailers or corrugated shipping boxes. 
• There is no need in our industry – eCommerce packaging – for bioplastic because our packaging is not used for food and is highly unlikely to become litter. As such, EcoEnclose's packaging line contains:
  • Recycled and recyclable plastic (bubble mailers, poly mailers); OR
  • Paper-based and 100% recycled, the items are naturally biodegradable (i.e., compostable) and recyclable.

Read more on our blog: Compostable vs Biodegradable Packaging