While conventional plastics such as polyethylene and polystyrene are derived from fossil fuels, bioplastics, such as polylactic acid (PLA Products), are made from renewable resources such as starch from corn or sugar cane. Biodegradeable plastics (not to be confused with bioplastics), which break down under certain circumstances, can be derived from either agricultural or petrochemical sources.
In fact, biodegradeable plastics have been used in niche applications for years. But the consumer items have a shorter history. In the early 1990s, biodegradable plastic bags and plates, made of conventional polymers, such as polyolefin, mixed with a starch compound, were touted as a green alternative. Unfortunately, these products fell short of consumer expectations.
And therein lies an important distinction: the meaning of the terms biodegradable and compostable. While a material can be labeled biodegradable (referring to the process whereby microorganisms cause decomposition and assimilation), it may not necessarily be compostable, the process by which material biodegrades to produce carbon dioxide, water and humus within a specified period of time. This is what happens to organic waste that is processed in a municipal compost system or in your backyard composter.
Confused? It gets worse. Beyond ‘biodegradable’ and ‘compostable’, today’s next generation of greener products may be labeled as oxo-biodegradeable, hydro-biodegradable, photo-biodegradable or water soluble, which speaks to the chemical process by which these materials break down.
The bottom line is, not all biodegradable plastics are created equal and there are a lot of misleading claims out there. Fortunately, you don’t need a chemistry degree to sort it all out.
If you think that opting for “green” plastics on a day-to-day basis is a way of doing your part to help address our growing landfill problem, think again.
When consumers hear the term “biodegradable”, they think that somehow things are going to magically disappear no matter what they do, ranging from littering to putting them in landfill. However, the reality is, none of that happens.
Why? Because landfills are essentially built to “entomb” waste, preventing exposure to air, moisture and sunlight. So even biodegradable waste won’t break down very much in a landfill. That’s why newspapers found in landfills are still readable 35 years later.
The notion of making plastic food container biodegradable and then sending them to landfill is really oxymoronic. Which is why consumers should look for compostable, not biodegradable products. By calling things ‘compostable’, you signal to the consumer that this is something you need to handle differently.