Judith Enck (ex dipendente EPA) e Jan Dell (ingegnere chimico) su The Atlantic discutono i chiari limiti del riciclo della plastica e del perchè questo processo non abbia funzionato in passato e non funzionerà in futuro, nonostante gli annunci roboanti di varie aziende.

Il riciclo di plastica, infatti, è un processo complesso: il problema principale è che la parola “plastica” descrive molti polimeri diversi, che a sua volta contengono diversi coloranti ed additivi.

For example, polyethylene terephthalate (PET#1) bottles cannot be recycled with PET#1 clamshells, which are a different PET#1 material, and green PET#1 bottles cannot be recycled with clear PET#1 bottles (which is why South Korea has outlawed colored PET#1 bottles.) High-density polyethylene (HDPE#2), polyvinyl chloride (PVC#3), low-density polyethylene (LDPE#4), polypropylene (PP#5), and polystyrene (PS#6) all must be separated for recycling.

L’altro problema principale è che il processo di riciclo è inefficiente dal punto di vista economico e persino deleterio per la salute delle comunità che vivono nei pressi delle aziende che se ne occupano:

Unlike metal and glass, plastics are not inert. Plastic products can include toxic additives and absorb chemicals, and are generally collected in curbside bins filled with possibly dangerous materials such as plastic pesticide containers. According to a report published by the Canadian government, toxicity risks in recycled plastic prohibit “the vast majority of plastic products and packaging produced” from being recycled into food-grade packaging.

Nonostante queste problematiche, note da tempo, l’industria della plastica continua a sostenere il riciclo della plastica con metodi che ricordano quelli adoperati dall’industra del tabacco.

Quando si parla di riciclo della plastica, si possono incontrare due approcci diversi: il riciclo meccanico (metodo utilizzato da decenni), e il riciclo chimico. Quest’ultimo è stato promosso con grande entusiasmo da Dow Chemical:

In 2018, Dow Chemical claimed that the Renewlogy chemical-recycling plant in Salt Lake City was able to reprocess mixed plastic waste from Boise, Idaho, households through the “Hefty EnergyBag” program and turn it into diesel fuel. As Reuters exposed in a 2021 investigation, however, all the different types of plastic waste contaminated the pyrolysis process. Today, Boise burns its mixed plastic waste in cement kilns, resulting in climate-warming carbon emissions.

Il riciclo della plastica non è un argomento nuovo, infatti è stato discusso ampiamente negli anni scorsi, specialmente a fine 2019 in seguito alla decisione della Cina di interrompere l’importazione di plastica da riciclare.

Nel 2019, NPR ha affrontato il tema del riciclo in due episodi di Planet Money dai titoli “A Mob Boss, A Garbage Boat and Why We Recycle” e “So, should we recycle?“. Nel 2020, NPR ha di nuovo approfondito l’argomento in un episodio dal titolo “Waste Land“:

 It’s not that you can’t physically recycle other plastics. It’s just that it doesn’t usually make sense economically. And heartbreakingly, it doesn’t usually make sense environmentally either.

In questo episodio NPR si occupa di capire perchè la popolazione sia stata portata a credere che la plastica sia un materiale riciclabile:

So how did millions of Americans come to believe that most plastic would be recycled when that’s not actually true?

La giornalista Laura Sullivan è andata a rintracciare i documenti che dimostrano come l’industra della plastica sia sempre stata a conoscenza dell’impossibilità del riciclo, almeno sin dal 1973:

 A report was sent to top oil and plastic executives in 1973. It says recycling plastic is nearly impossible. There is no recovery from obsolete products, it says. Recycling is costly. Sorting it is infeasible. Plus, it says plastic degrades every time you try to reuse it. So the oil and plastic industry knew. They’ve known for almost 50 years.

Col tempo, la fama della plastica si era deteriorata, per cui si è reso necessario sviluppare una nuova campagna promozionale per migliorare l’immagine della plastica:

The industry decided to advertise its way out of a can’t-recycle-it problem.

These commercials carried an environmentalist message, but they were paid for by the oil and plastic companies, eventually leading to a $50-million-a-year industry-wide ad campaign promoting plastic. So I asked Larry, why? Why spend tens of millions of dollars telling people to recycle plastic when they knew recycling plastic wasn’t going to work? And that’s when he said it, the point of the whole thing. “If the public thinks that recycling is working, then they’re not going to be as concerned about the environment.” […] But there was one more part of this campaign, the final piece that did stick around – that recycling symbol with the numbers in the middle. This symbol has created so much confusion about what is and is not recyclable.

Di questo argomento parla anche Politico.eu:

But plastic poses a particular problem. Of the 29 million tons of plastic waste collected in the EU in 2018, less than a third was recycled. About a quarter went into landfills, and about 43 percent was burned in incineration plants.

“Plastic recycling is largely a fraud,” said Jim Puckett, the executive director of the Basel Action Network, an NGO in the U.S. that works to end illegal waste trade. “It’s been sold to us as being the answer to all the plastic waste and consumption, but in fact it really has some fundamental aspects of non-circularity that are going to plague that myth and dream forever.”

“We can’t recycle our way out of the problem. The message should have been: Don’t use so much plastic.”