The truth about “PLA” is it truly compostable/biodegradable?
Polylactic acid is plastic made from sugars in cassava, sugarcane and corn starch and they can be broken down by microorganisms, unlike conventional plastics (HDPE, PE, LDPE, PE, etc). There is however one very important element that is often overlooked which is the conditions necessary for the plastics to breakdown. The majority of all bio-plastics require a very high thermal trigger (above 60 degrees celsius) and circulation of air for prolonged periods of time in order for the plastics to biodegrade. These very specific conditions can only be provided by an industrial composting facility. If we take a look at the majority of cities around the world, there are very few composters integrated into waste management and even fewer who are willing to accept PLA. When PLA ends up in land-fill it will not breakdown and biodegrade, it will react very similarly to fossil-based plastics.
Additional problems with PLA include:
- If it is mixed with conventional plastic recycling it can completely ruin the batch as there is a difference in melting temperatures.
- the land resources needed to grow and maintain PLA production are competing with crops for feeding us.
- it is also more expensive.
