Compostable v Biodegradable
The age old question: What is the difference between biodegradable and compostable?
There is a significant difference, though one commonly thinks of these descriptive terms as one and the same. They are not!
Made from plant materials, compostable products break down into non-toxic components during the composting process. Other degradable-claiming products break down into harmful chemicals, smaller fragments that could harm the environment, or simply do not work as advertised. Some confuse composting with biodegrading by thinking that both mean defragmentation, where the material degrades into smaller pieces but does not decay in any molecular way.
The term "greenwashing" came about as marketers took advantage of buzzwords or spin to mislead customers about how beneficial their products were for the environment. This has lead to much confusion regarding the meaning of such key terms as: degradable, oxo-degradable, biodegradable, and compostable.
The term "degradable" defines a broad category of products that, when exposed to sunlight, heat, moisture, etc., will break down and disintegrate over time. That said, almost anything will degrade, given enough time! Concrete will eventually degrade, as will steel.
Even if something is degradable, it might not be beneficial to the environment. Harmful micro-plastics can be created as degradable but non-compostable plastics break down into thousands of tiny fragments. An example would be micro-beads in a hand cleaner or lotion.
Biodegradable products are anything that undergoes degradation resulting from the action of naturally occurring microorganisms, such as bacteria, fungi, and algae. So something is considered to be biodegradable when living things can break it down.
The prefix "bio" makes this term seem very eco-friendly. However, just because nature breaks these products down does not mean the results are any better for the environment. It is very important to specify the setting and conditions in which biodegradation is intended to take place.
Oxo-degradable plastics contain polyethylene and additives (including iron, nickel, and cobalt).
Once disposed, these plastics undergo oxidative degradation, a process requiring oxygen, ultraviolet light, and heat. The degraded plastic becomes brittle and fragments very easily, creating micro-plastics that are incredibly harmful to the environment.
Oxo-degradable products are considered in most environmentally conscious quarters to be generally harmful to the environment. They are not compostable or suitable for recycling with mainstream plastics, so they must be thrown away into general waste recepticles.
The American Society for Testing and Materials defines compostables as anything that undergoes degradation by biological processes during composting to yield carbon dioxide, water, inorganic compounds, and biomass, at a rate consistent with other compostable materials. It must leave no visible, distinguishable, or toxic residue.
Compostable products, after their degradation process, will leave behind humus, which is non-toxic, full of nutrients, and nourishes plants and soil.
To go through a composting process, organic waste requires the proper levels of heat, water, and oxygen. Compostable products have a positive impact on the environment, but compostable waste must be sent to a compost facility to ensure proper waste management.
How to ensure the right eco-friendly product for your needs
When purchasing a product, it is important to consider which end-of-life option is best for you. If you've made the choice to use compostable packaging, it is important to check for compostability certification! Until 2002, there were no specifications or tests to legally prove compostability, allowing confusion and skepticism to exist for decades.
Some manufacturers, unable to meet the standards of these specifications, will reference ASTM 6954 or ISO 14855, claiming to be certified by some organization and to have met some standard for biodegradation or compostability. Don’t let them fool you! Virtually all of these types of claims are merely standard procedures to be followed for conducting tests, and have no requirements for heavy metal content or disintegration ability.
The terms biodegradable and compostable are not interchangeable, and it is crucial that each type of product is sent to the proper waste management facility. The best way to be environmentally responsible and ensure the most positive effect on the environment is to choose authentic, certified compostable packaging.