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The general public has been told for years to carefully bin their plastic litter in the proper bin. Most people believe that doing this actually results in protecting the environment from plastic pollution.

This article mentions that the rate of plastic recycling in the US is as low as 5%, and around 9% in the world. In this other article it is mentioned that Europe reaches 30% and China 25%, which are still shockingly low proportions.

Apparently the main issue is not even the fact that people don't recycle or bad management (although that could explain why the US lags behind), it's the technological difficulty to recycle most types of plastic. But there is no detail about which amount of this proportion is due to lack of action by people, mismanagement by recycling companies, etc.

The first article ends with this quote:

“[P]lastic recycling is neither a safe nor realistic solution to reducing plastic waste and pollution in the United States.”

Is plastic recycling really not a viable solution? For example, what would be the maximum recycling rate that can be achieved with current technology? Are there places in the world which reach a really high recycling rate?

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    Great question, but before comparing recycling rates you need to know what definition of recycling is used. For example, does it include reuse or thermal recycling (burning waste to generate heat and/or electricity).
    – THelper
    Nov 13, 2022 at 7:01

4 Answers 4

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Chemical plastic recycling is viable and creates a product as good as plastic newly created from petroleum. Mechanical, not so much, it leads to poor quality plastic that tears very easily and is unsuitable for food packaging for example due to contamination concerns.

There are two ways chemical recycling can be done:

  1. Burn plastic into carbon dioxide (and water). Capture carbon dioxide. Capture waste heat, distributing it in a district heating network. Create hydrogen from water using electrolysis. Combine hydrogen and carbon dioxide into methane. Post-process the methane to create longer chain hydrocarbons, and eventually the plastic molecules you want.

  2. Create petrochemicals directly from plastic, avoiding the need to convert it to carbon dioxide by burning and later back to hydrocarbons. Those petrochemicals can then be processed to create the needed plastic molecules. At least Alterra Energy has such a process.

Of these options, (2) has probably greater energy efficiency (leading to cheaper recycling), but (1) isn't bad either assuming you have a use for the waste heat. A benefit of (1) is that it allows creating plastic from any waste containing carbon -- cardboard packaging, newspapers, wood and plastic.

So if you want to create plastic from wood or paper waste, (1) is the better option. And if you don't want to recycle plastic to a separate stream (which (2) requires) but rather process a single energy waste stream, (1) is better since it can process nearly any waste apart from glass and metal that don't burn.

Currently most plastic recycling is mechanical, and that explains why recycled plastic has such a crap quality.

I think that given the current processing of plastic waste, it doesn't make sense to separate plastic waste to a separate stream. You are then supporting the creation of inferior quality product, leading to the proliferation of bad quality plastic bags that tear on the first use, leading to people buying a single new plastic bad and using it exactly once, as opposed to using the same plastic bag 100 times (which used to be possible before the disastrous recycling of plastic and usage of the poor recycled plastics in plastic bags began).

But in the future, if technology (2) proves superior to technology (1), then it may begin to make sense to have a separate plastic waste stream.

Also, I'm sure that in the future, new non-recycled plastic will be created not from petroleum but from trees.

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    Thank you for your answer. But what about the different types of plastic? Do these two methods differ in the different types that they can treat?
    – Erwan
    Nov 15, 2022 at 20:56
  • What I was going to ask too. Of the seven common types of plastic only the first two are easily recyclable ourworldindata.org/…
    – MocBird
    Dec 9, 2022 at 6:16
  • Burning plastic can treat any plastic, maybe apart from PVC the burning of which produces toxic gases. Chemical recycling, I assume it has probably similar restriction, because PVC has chlorine and plastics are made from hydrocarbons (containing only hydrogen and carbon), maybe adding oxygen, but the feedstocks don't have chlorine. So in the future, only PVC remains a problem.
    – juhist
    Dec 10, 2022 at 9:23
  • @juhist can you provide an example where Chemical plastic recycling is up and running? If yes, I’m interested to know what the energy source is, given that the energy usage of Chemical plastic recycling must be huge?
    – minisaurus
    Feb 24, 2023 at 16:33
  • Actually the carbon dioxide process is the one that requires huge energy input in the form of hydrogen (which would be provided mainly by excess wind energy during windy times in the future). Chemical recycling, not so much. I think chemical recycling might arrive faster than the carbon dioxide based process, I already provided Alterra Energy as a sample. Not sure if they have built recycling plants yet.
    – juhist
    Feb 25, 2023 at 17:29
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Great questions and important ones

Is plastic recycling really not a viable solution?

Sustainability talks about 3 Rs: "reduce, reuse, recycle" and "recycle" is the last R. Hence the effective way we can reduce plastic waste is to reduce its usage, e.g. use water filter systems as an alternative to buying water in plastic bottles.

Reduction of plastic usage would also avoid the need to tackle the second question about "recycling rate" which generally depends on the type of plastic (how many times can plastic be recycled before it looses its quality) and recycling infrastructure (collecting, transporting, recycling, reselling) and citizens awareness about the need to recycle.

Note that even if Europe has high awareness, it also sends part of its plastic to Asia where the awareness is lower and the plastic is dumped in Asian waters.

So recycling alone is definitely not a solution and people should consider reduction of its usage and make "reduce and reuse" a part of their lifestyle, e.g. use reusable plates and cutlery instead of single-use ones.

Are there places in the world which reach a really high recycling rate?

Norway and Switzerland recycle more than 90% of plastic bottles, but again plastic has a limit on a number of times it can be recycled comparing to glass recycling, for instance, which can be performed virtually indefinitely.

Disclaimer: I own and wrote roktao.com linked articles.

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The accepted answer is good, but it is too simple. There is a lot more to it.

Between the described advanced processes and mechanical recycling there are a lot of other different processes. The first one was just melting in different stages. In the first stage at a temperature between 100 and 150 degrees Celsius the weakest plastic would melt and would be easily separated. The rest would go to the next stage at higher temperature. The process was rarely implemented because it was expensive. But there are still many processes based on melting or partial melting of scrap plastic in operation, not just mechanical recycling. Just as an example make an internet search with the keywords plastic tarmac.

The real reason why what is being told to the public changed so much is the energy cost. Not only the rise in the price of fossil fuels pushed up all the other costs, it also increased the cost of plastic recycling. On the other side a lot of countries began to use rubbish incinerators to generate energy, but rubbish does not contain so much energy, so it was decided to beef up the energy content by reducing the amount of plastic that is recycled. Everything else is just confusion created on purpose.

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In May 2023, a few months after I asked this question, I read this Guardian article: Greenpeace also criticizes plastic recycling, even saying that it is incompatible with circular economy:

"the toxicity of plastic actually increases with recycling. Plastics have no place in a circular economy and it’s clear that the only real solution to ending plastic pollution is to massively reduce plastic production."

Since the 1950s about 8bn tonnes of plastic has been produced. The Greenpeace report catalogues peer-reviewed research and international studies showing not only that just a tiny proportion (9%) of plastics are ever recycled, but also that those that are end up with higher concentrations of toxic chemicals, multiplying their potential harm to human, animal and environmental health.

"Simply put, plastic poisons the circular economy and our bodies, and pollutes air, water and food. We should not recycle plastics that contain toxic chemicals. Real solutions to the plastics crisis will require global controls on chemicals in plastics and significant reductions in plastic production."

So according to this Greenpeace report, plastic recycling only serves as an excuse for the plastic industry to keep increasing production, even though the impact of recycling is essentially negative.


February 2024 update: another report confirms that plastics producers deceived public about recycling

Companies knew for decades recycling was not viable but promoted it regardless, Center for Climate Integrity study finds

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