No, the purple bags are not recycled

facts

Indeed, since the start of food waste collection, the purple bags (after emptying their contents at the sorting center) have been sent to the incinerator. They are not biodegradable and are not currently recycled either. Last year, during the launch, the sun He wrote that the city was working on ways to properly clean the bags to allow them to be recycled, and that we would then hope to find a solution around mid-2023, but that has clearly not happened yet.

“We are currently conducting trials to recycle plastic bags. I cannot say more at this time, as the tests have not been completed and the results analyzed,” a Quebec City spokesperson told me Thursday morning.

So the purple bags, the contents of which are sent to a bioprocessing center in Quebec, are always incinerated after use.

Now there are reasons behind all this. “They have no choice but to separate the bags from their contents, because we cannot put these bags in biomethane,” explains Pierre Sarrazin, a chemical engineering expert who has already worked on this type of bag with municipalities. In Europe, they tried, but they banned mechanical cutting tools. »

This is because to withstand transportation in a garbage truck, it was necessary to choose a plastic resin that is very resistant, but has the disadvantage (by definition) of not tearing well. The alternative would have been brown trash, but that would have involved separate collection, with thousands of truck trips and millions of additional dollars that come with it.

We also couldn’t use biodegradable plastics, Mr. Sarrazin continues, because these bags are made to decompose well in compost piles, or outdoors. In the methane bioreactor, there is no oxygen, and the bacteria present are not the same, and they have difficulty breaking down biodegradable plastics.

The last option therefore remains recycling, but to achieve this, the plastic bags must be very clean, Mr. Sarrazin points out. “For polyethylene recycling [dont sont faits les sacs mauves, ndlr]We will heat it to melt it, and the solid pollutants will decompose. In the case of food scraps, they will burn, off-gas, and risk introducing accidental defects into the recycled product.

However, currently “used” purple bags cannot be cleaned enough to make good recycled plastic. “Within a few years, it will be possible to recycle them better,” Mr. Sarrazin predicts.

Cremating bodies in the meantime isn’t ideal, he says, but it’s not catastrophic either. “As long as the plastic is not circulating in the environment, the impact is very low. Whatever the end of its life is, even if it is not the best environmentally, it is still low,” Mr. Sarrazin emphasizes.

Judgment

TRUE. Initially, recycling of purple bags was supposed to begin this year, but that is not the case and it is not clear when exactly that will happen. We also can’t make them out of biodegradable plastic, because that’s a material that doesn’t lend itself well to the biomethanation process.