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Plastic production has grown steadily in recent decades, from 1.5 million tonnes in 1950 to 359 million tonnes in 2018; of course, the amount of plastic waste increases in the same way. Almost three quarters of the trash found on the world’s beaches is plastic (packaging, bottles, caps, etc.), and 5 trillion pieces of plastic float in the oceans. It is estimated that by 2050, all species of seabirds will ingest plastic regularly. To limit the damage, it becomes crucial to increase the recycling rate of plastic waste. But how exactly is this process carried out?

Almost a third of plastic waste are recycled in Europe, but 25% are buried; France is a poor student, with a packaging waste recycling rate of less than 30%. The three main sources of plastic waste in the European Union are packaging (around 40%), the construction sector (around 20%) and the sector comprising plastics for domestic or professional use (household appliances, furniture, medical equipment, etc. .). Since January 1, 2021, the sale and provision of certain single-use plastic products (cutlery, plates, cups, straws, stirrers, etc.) have been gradually banned.

In 2019, globally, researchers estimated that plastic production and incineration released more than 850 million tonnes of greenhouse gases into the atmosphere. By 2050, these emissions could reach 2.8 billion tonnes – a figure that could be significantly reduced through better recycling. However, the wide variety of plastics that are discarded complicates the recycling process, increases costs and impacts the quality of the finished product.

Different families of plastics

Recycling starts with sorting waste. For it to be effective, it is necessary to distinguish between the different types of plastics that exist. For this, it is necessary to rely on the classification implemented by the plastics industry in the 1980s; this takes the form of a logo, a Möbius triangle, which indicates that the product is recyclable. But be careful, this does not in any way mean that it will necessarily be recycled!

Inside this triangle is a number, which indicates the composition of the plastic; there are a total of seven categories of recyclable plastics and so far, only two of them are recycled everywhere in France: numbers 1 and 2, which correspond respectively to polyethylene terephthalate (PET) and high density polyethylene (HDPE). These are typically bottles of water and milk, bottles of cosmetic products (shower gel, shampoo, etc.) and household products (detergents, detergents, etc.).

EU plastic recycling figures
Currently, almost a third of plastic waste is recycled in the European Union. © EU / EP

Other plastic packaging (PVC, polypropylene, polystyrene, etc.) does not contain enough raw material, so recycling is not economically viable. The best way to recover this waste is to incinerate it to recover heat energy. Note that several municipalities benefit from the “extension of sorting instructions” (ECT), which invites users to recycle all of their plastic packaging (including plastic bags and films, yoghurt pots, food trays, etc.).

Once collected by the household waste collection services, these plastics arrive at the sorting center where they are sorted by family (PET, HDPE, polypropylene, etc.), then are compacted in the form of huge bundles, called “bales”. of plastic ”. They are then transported, depending on their nature, to a regeneration plant (or directly to an incineration plant).

Grinding, cleaning, purification

As part of the regeneration, the plastics in the bales are cleaned, crushed, and then softened. This results in tiny plastic flakes, which are washed with hot water and detergent to remove all impurities (such as label residue and glue). To improve the quality of the flakes, the regenerators sometimes perform an additional purification step by optical sorting.

Note that PET flakes are often mixed with HDPE flakes (which come from bottle caps). To separate them, we use a flotation system, because these two materials do not have the same density. Then the flakes are heated to high temperature (around 280 ° C) to be transformed into granules. These are the ones that are used by recycling plants to produce new plastic items. The PET granules are then purified by polycondensation.

Note that each type of granule is recycled for a specific use. HDPE granules are used, for example, in the manufacture of watering cans, hoses or car seats for children. PET granules are used for the (synthetic) stuffing of duvets, pillows or teddy bears, to manufacture new packaging (bottles), clothing in “fleece” material, etc.

Recycling (too) long delegated

While industrialized countries all have recycling centers, they are not capable of handling the huge amounts of rubbish produced by their inhabitants. This is why they have long exported a large part of their plastic waste, particularly to China, Thailand and Malaysia. Until 2018, more than half of the waste exported worldwide was sent to China (which lacked plastic to fuel its own industry).

The problem that quickly arose was that many arrivals were made up of mixtures of waste, unsorted, some of which were impossible to recycle. As a result, unusable plastics have accumulated, causing dramatic ecological consequences throughout Southeast Asia. China therefore ended up banning the import of plastic (among other waste) and the global recycling network gradually shifted to Malaysia, Thailand and Vietnam. The countries that shed their waste have each undertaken to find other solutions: some have turned to incineration, others are trying to develop their recycling capacities, others are increasing the price of packaging to offset costs. , etc.

The French government has for its part committed to achieving a rate of 100% recycled plastic by 2025. In the meantime, the most effective way to fight against the increase in plastic waste is still to reduce purchases involving packaging or a plastic product. For this, it is necessary to privilege as much as possible the purchases of food “in bulk”, to manufacture its own household products and to ban the use of single-use plastic objects.


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