What is the difference between “biodegradable” and “compostable”?
Biodegradable means that the products break down through a naturally occurring microorganism, such as fungi or bacteria over a period of time. Biodegradable products are usually made from plant or animal sources. Biodegradable products can create methane, a greenhouse gas with 62 times the Global Warming Potential of carbon dioxide when dumped into landfills. Also, biodegradable waste may contain toxins. Compostable plastics mean that the products must be able to break down into carbon dioxide, water, and biomass at the same rate as paper. Also, the broken down product should not produce any toxic material and should be able to support plant life. Compostable products are usually made from plant materials. Because biodegradable is used loosely with no legal enforced definition, compostability is more desirable for disposable products.
A “biodegradable” material can be decomposed by the action of microbes, such as bacteria and fungi, into basic elements or compounds where it is considered “food” for another living organism. Most manufactured products biodegrade slowly, if at all, and emit toxic substances throughout the decomposition process – the reason Green Building Pages differentiates between “biodegradable” and “non-toxic biodegradable”. These same microbes can also decompose a “compostable” material, and release nutrients and organic matter back into the earth; the material could theoretically be composted for garden soil. Something “compostable” is biodegradable by definition, however biodegradable does not necessarily mean “compostable”.
