Monday, June 20, 2011

Sorting Out Bioplastics: Which Bin Should They Go In?

Blog post based on: Breaking Down Bioplastics: Is the Bioplastic Cup Half Full or Half Empty? by Mary Catherine O’Connor, published in the Earth Island Journal, Summer 2011.

It has been a little bit since my last blog post, as I have been busy with other projects. But today, I have a very interesting topic that I find really summer appropriate as the iced lattes and teas season has rolled over. Is you beverage of choice served in a bioplastic cup? And if so, which kind is it and which bin should it goes in? The article by Mary Catherine O’Connor explores the different types of bioplastics and what we should be doing with them. There are different types of bioplastic: polylactic acid (PLA) and bio-based PET or high-density polyethylene (HDPE) PlantBottle. Let’s take a look the different types of bioplastics:


PLA is a bioplastic made from corn by the company NatureWorks. Depending on the amount of pesticides and fertilizers used to grown the corn, it can affect its actual “Green Status”. Another issue with the corn-based PLA is one that comes up also in the ethanol talks: shouldn’t we be using corn to feed the planet rather than for packaging or fuel? To this, everyone can have his or her own opinion. So in which bin do you think you should put your PLA cup? Recycle or compost? PLA should be composted, unfortunately, it is often mistaken by people to be another kind of plastic and ends up in recycling facilities, where it will be discarded and put in a landfill. According to Teresa Clark from Enso Bottle, PLA requires an environment with oxygen, heat and moisture in order to begin breaking down and these conditions are not often found in landfills ( PLA can also be a problem for composters as it makes it harder to sort through the plastics wrongly put in compost bin and that will also redirect the PLA to the landfill. They are currently only two companies that recycle PLA in the world, one in Europe and another in Wisconsin. Recycling PLA allows the embedded energy inside each cup to be reused (O’Connor, 2011) rather than lost through the composting process.

Bio-based PET or HDPE PlantBottle

The PET or HDPE are made partially to completely from plants. These bottles have the exact same chemical structure than plastic bottles that are made from oil. Currently, Coca-Cola has a 30% plant-based PET bottle and PepsiCo developed a 100% plant-based PET bottle. Because they have the same chemical structure, bio-based PET and HDPE should be recycled and not composted even though the name of the PlantBottle is slightly misleading and would clue most of us to dispose of this bioplastic in the compost bin!

So whether or not you agree with the fact that plant-based products are a greener alternative to the regular plastic, disposing of them correctly will help them achieve what they were created for.

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