Biodegradable plastics are plastics degraded by microorganisms – usually bacteria – into water, carbon dioxide (or methane) and biomass under specified conditions.
Most plastics are derived from the processing of non-renewable petroleum reserves. Plastics derived from biomass production are known as ‘bioplastics.’ One of the most common bioplastics is PLA (Polylactic Acid), which is derived from renewable resources like corn starch or sugar cane and widely claimed to be compostable. PLA usage includes 3-D printing, plastic films, bottles, and biodegradable medical devices (e.g. screws, pins, plates etc.), breaking down inside the body within 6 months to 2 years.
Although there are various grades of PLA material with each derived from a sustainable source, there is widespread coverage that a PLA bottle would naturally degrade. In a marine environment this could still take up to 2 years (better than conventional plastics which could take several hundreds of years), this doesn’t reflect the damage caused to the marine environment during this time.
With advisory notices stating materials are compostable ‘in certain conditions under certain environments’ raises the questions further. The conditions and environments lead to the answer of an industrial incinerator being required, heating at 140+ degrees which has limited facilities even on a global scale. Without the high temperature and other ingredients needed to break the PLA down, it will happily sit in landfill with all other plastics.
The issue needs to be addressed that plastic is plastic and rather than just keep producing new material, look at ways we can reduce the amount of material produced. Manufacturing products with a waste management process from the outset; where we can make, use and recycle back into material. Considering every piece of plastic ever produced still exists in some shape or form, let’s focus on producing less and recycling more.