Have you noticed the different new "green" bags in your supermarket or grocer? They claim to be 100 percent compostable et biodégradable.
La plupart d'entre eux sont fabriqués à partir de PLA, un bioplastique. Le bioplastique est un nouveau type de plastique généralement fabriqué à partir d'amidon ou de sucres végétaux, et non à partir de pétrole. Avoir le nom BIO dans le plastique peut être un peu trompeur car ils ne se biodégradent pas comme une peau de banane.
Alors le PLA est-il vraiment compostable ?
The short answer is YES! But the plastic is only compostable if you bring it to an industrial composting facility that accepts PLA plastic, and there aren't that many.
Voyons la définition.
1. Biodegrade – break down into carbon dioxide, water, biomass at the same rate as cellulose (paper).
2. Disintegrate – the material is indistinguishable in the compost, that it is not visible and needs to be screened out.
3. Eco-toxicity – biodegradation does not produce any toxic material, and the compost can support plant growth.
Biodegradable Plastic is plastic which will degrade from the action of naturally occurring microorganism, such as bacteria, fungi, etc. over some time. Note that there is no requirement for leaving "no toxic residue," and as well as no requirement for the time it needs to take to biodegrade. This can actually take between 100 – 1000 years. Not helping the environment at all.
Degradable Plastic is plastic which will undergo a significant change in its chemical structure under specific environmental conditions resulting in a loss of some properties. Please note that there is no requirement that the plastic has to degrade from the action of "naturally occurring microorganism" or any of the other criteria required for compostable plastics. A plastic, therefore, may be degradable but not biodegradable, or it may be biodegradable but not compostable (that is, it breaks down too slowly to be called compostable or leaves toxic residue).
Qu'est-ce que l'APL ?
PLA or Polylactic Acid is mainly made from génétiquement modifié cornstarch, which is so kindly being produced by NatureWorks, a subsidiary company from Cargill, the biggest producer of modified corn in the world.
Le PLA est fabriqué à partir d'une ressource "renouvelable", pas de pétrole, et lorsqu'il est incinéré, il ne laissera que du dioxyde de carbone et de l'eau. C'est une excellente nouvelle, non ???
BUTIt requires an industrial composting facility where a cocktail of microorganisms is continually being fed, and a temperature of 60 C is required for 10 days. It also needs the right amount of moisture and oxygen to degrade in 3 – 6 months.
In a properly engineered landfill, nothing is meant to degrade. No bag – reusable or conventional plastic shopping bag – will decompose in a landfill. Which actually helps the environment by not producing dangerous greenhouse gases like methane.
In fact, your compost wouldn't even get to the desired temperature of 60 degrees Celcius or 140 Fahrenheit. The standard home compost reaches a maximum of 43- 48 C, or 110 – 120 F.
It is not recommended to put these PLA biodegradable plastics into your home compost, they might remain there for 100 – 1000 years.
Où va mon « sac plastique biodégradable PLA » ?
You probably think you are doing a good thing for the environment by buying a green bag that claims to be biodégradable et compostable.
Assez juste, les entreprises les font paraître vertes et agréables, et la publicité est tout simplement trompeuse. Oui, ils se dégradent mais uniquement dans une installation de compostage industriel. Aux États-Unis, il n'y en a que 113.
See if you can find one in your area by going to find a composteur.
Je réside actuellement au Québec, et j'ai trouvé 2 établissements dans toute la province de Québec. DEUX établissements pour tout le Québec ???
Notre supermarché Metro local distribue 15 000 sacs en plastique par semaine, sans compter les sacs de fruits et légumes. Qui peut gérer ces quantités de déchets ?
The other problem we find with PLA is, people often think it is recyclable, just like our standard plastic, and therefore it ends up in the same bin. This misconception causes lots of problems in the plastic recycling world as your PLA products to act as a contaminant in hydrocarbon-based resins such as PE, PP, PET, and PS.
It costs millions each year for recycling facilities to sort through the different plastics since PLA looks very similar to standard plastic, and the machines can't identify the difference yet.
Quelle est l'alternative ?
So far, the best solution we have is to minimize our use of single-use plastics overall. Bring your green shopping bag to the grocer, and if you like using straws, consider swapping to natures Paille.
Voici quelques conseils supplémentaires pour minimiser l'utilisation-de plastique à usage unique.
We don't have a way to dispose of PLA products properly. Buying items that are not heavily packaged in plastic is a good alternative. We have to become aware of the fact that most bioplastics aren't good for the environment either.
Aidons et faisons passer le mot. Nous savons qu'il existe des alternatives, la plupart du temps, il s'agit simplement de vous éduquer, vous et vos amis, pour prendre de meilleures décisions. J'espère que vous pourrez quitter cet article avec plus de connaissances sur les différents types de plastiques.