As we have just seen in the last chapter, based on life cycle studies, plastic is usually the lowest impact option even with low or no recycling. Having said that, recycling does offer the opportunity to further reduce impact, so it is a topic well worth exploring.
As exposed in The Plastics Paradox book, most of what we have been told about plastics and the environment is simply untrue, meaning that decades of science say the opposite. So, let us examine these common assertions about plastics recycling and see what science says about them.
Plastics Recycling is Needed to Prevent Litter & Pollution
We hear that increasing the recycling rate will solve the problem of “plastic pollution.” Again, scientists have revealed the facts. It turns out that what many are calling plastic “pollution” is really litter. Whereas pollution is associated with companies, litter is caused by people, and the solutions to that involve changing the behaviour of those people via education, deposits, and fines.
E. Carpenter & S. Wolverton, Plastic litter in streams: The behavioral archaeology of a pervasive environmental problem, Applied Geography, 84, pp. 93–101, 2017
Will increased recycling really help to reduce litter? While there is no evidence that people litter less when a product is recyclable, often recycling does lead to less litter indirectly. It is common to impose a deposit on items; that leads to a large decrease in litter because, once the product has value, due to the deposit, people do not drop it anymore, or if they do, someone else will pick it up to collect the deposit.
A good analogy here is plastic banknotes. They print billions of plastic banknotes every year — how many do you see in the streets, floating down rivers, or on beaches? We never see them littered because although they are small and easily lost, they have value, so people take care of them.
Recycling is Needed to Make Plastics Green
One of the most common claims is that we need to recycle plastics at a much higher rate for plastics to become truly green. Scores of life cycle studies spanning decades show plastics cause the least impact. Replacing them with alternatives like paper, cotton, metals, or glass increases harm, not only in terms of greenhouse gas but also waste created, fossil fuel used, and total impact across all the factors included in modern life cycle studies.
Some of those life cycle studies also ran scenarios assuming different recycling rates for plastics and other materials. As previously mentioned, they concluded plastics create less impact even with low or no recycling at all. So, it is not correct to say that we are waiting for recycling to make plastics the right choice for the environment.
Denkstatt The impact of plastic packaging on life cycle energy consumption and greenhouse gas emissions in Europe, Executive Summary July, 2011
Even so, it is correct to encourage recycling because recycled plastic needs far less energy and creates far less greenhouse gas than new plastic does. Typical reductions are 70–80%, and that is achieved using the standard, cheap, and simple method known as “mechanical recycling.” That entails collecting the plastic, separating, washing, shredding, and remoulding it into a new product.
Life Cycle Impacts of Plastic Packaging Compared to Substitutes in the United States and Canada, Franklin Associates for The Plastics Division of the American Chemistry Council, 2018
C. Wong, A Study of Plastic Recycling Supply Chain, University of Hull, 2010
The Plastics Can Only Be Recycled Once Myth
You may have heard that plastics can only be recycled a couple of times, whereas metal and glass can be infinitely recycled, so we should pick metal and glass over plastic. Is that correct? No, it is not. In fact, plastic can be recycled many times with good properties, as shown by multiple peer-reviewed studies.
Here is a quote from a study in which they put LDPE through an extruder to recycle it one hundred times. They found good properties until the fortieth cycle and said:
“With these results on hand, it could be concluded that LDPE could be extruded for up to 40 times without significantly changing its processability and long-time mechanical properties”
H. Jin et al., The effect of extensive mechanical recycling on the properties of low density polyethylene, Polymer Degradation and Stability, 97, pp. 2262–2272, 2012
Plastic pellets (sometimes incorrectly referred to as “nurdles” by NGOs)
Similar studies have shown that other common plastics like HDPE, PP, and PET can be recycled multiple times with good retention of properties.
A. Boldizar et al., Simulated recycling of post-consumer high density polyethylene material, Polymer Degradation and Stability, 68 (3), pp. 317–319, 2000
R. Mnif & R. Elleuch, Effects of reprocessing cycles and ageing on the rheological and mechanical properties of virgin-recycled HDPE blends, Matériaux & Techniques 103, 704, 2015
M. Mihelčič et al., Influence of Stabilization Additive on Rheological, Thermal and Mechanical Properties of Recycled Polypropylene, Polymers, 14 (24), 5438, 2022
B. von Vacano et al., Elucidating pathways of polypropylene chain cleavage and stabilization for multiple loop mechanical recycling, Journal of Polymer Science, pp. 1–10, 2023
As for the claim that metal and glass can be infinitely recycled, we know that no material can be recycled indefinitely because of contamination and losses during the process. Such losses are well documented for both metals and glass.
Soft Plastics Like LDPE Cannot Be Recycled Myth
How can mechanical recycling be so widely applicable when we know soft plastics like bags cannot be recycled that way and that black or coloured plastics cannot be recycled mechanically? The simple answer is that those claims about recyclability are also untrue.
Soft plastic, like the low density polyethylene from shopping bags, can be recycled and are recycled. One company in Germany, Papier-Mettler, has recycled over 100,000 tons a year profitably for years, and they are not alone. Other companies have done so as well.
Soft plastic can cause jams in machines not designed to handle them, so rather than install the correct machines, many just label them as “unrecyclable,” even though this is not true. More responsible companies invest in equipment to solve the problem instead.
Black and Coloured Plastics Cannot Be Recycled Myth
Black and coloured plastics have also been labelled unrecyclable when, in fact, they can be recycled perfectly well. It’s just that some prefer not to have to deal with them because the resale value of coloured plastic is lower. So, rather than recycle them, some companies mislead the public by calling such materials “unrecyclable.”
Many years ago, it was found that the most common black colourant, carbon black, prevented plastics from being sorted for recycling automatically because that pigment confused the detectors. However, that problem was solved long ago by finding black colourants that do not interfere with sorting. I still see claims that black plastic cannot be sorted and recycled, but that is not the case.
What about coloured plastics? Sprite recently removed the iconic green colour from their PET bottles, so now they are colourless. Why? Because there is more demand for colourless recycled plastic, so the market value is higher. That’s why colourless plastics are preferred for recycling. Both coloured and uncoloured are equally recyclable, but let’s talk about what recyclable really means.
The Downcycling Myth
It is said that plastics cannot be recycled back into the same product again and again but must be made into other, lower-value products. Is that really the case, though? Can plastic be recycled into the same product, and do we always need to see the creation of different products as a negative?
PET bottles are a good example highlighting that yes indeed, bottles can be returned and recycled into new bottles not just once or twice but ten times or more. Then, when the plastic is no longer suitable for bottle-making, it can be spun into fibres and made into a fleece sweater instead. Some claim recycling plastics to make a different product is “downcycling,” but that line of thought baffles me. How can anyone believe that turning a cheap soda into a luxurious and durable fleece is downcycling? That seems like a breakdown in reasoning to me. This recycling of PET is not theoretical either; it has been done in enormous volumes in multiple countries for many years. By implementing a deposit system, return rates are extremely high, above 95%.
PET may be one example, but is it an outlier? What about other common plastics?
LDPE has been recycled 100 times with good retention of mechanical properties for the first 40 times. HDPE was recycled 50 times with good properties for the first 10 cycles. Polypropylene was reprocessed 50 times but was not of sufficient quality after the first 10. The idea that plastics cannot be recycled, or can only be recycled once at best, is simply not true.
H. Jin et al., The effect of extensive mechanical recycling on the properties of low density polyethylene, Polymer Degradation and Stability, 97, pp. 2262–2272, 2012
N. Benoit et al., High Density Polyethylene Degradation Followed by Closed-loop Recycling, Progress in Rubber, Plastics and Recycling Technology, 33 (1), 2017
M. Mihelčič et al., Influence of Stabilization Additive on Rheological, Thermal and Mechanical Properties of Recycled Polypropylene, Polymers, 14 (24), p. 5438, 2022
It should be mentioned that the number of recycling cycles can be increased by adding more stabiliser, better stabilisers, and other additives to protect the polymer chains and to repair the damage done. Tiny amounts of additive can give meaningful improvements, and advances in the field continue.
PVC can be and is recycled in large volumes. According to the Vinyl Institute, over 1 billion pounds of PVC is recycled every year in the US and Canada. It is surprising to many that one of the lower-impact materials is inherently flame retardant, highly durable, and non-toxic.
“The work presents a literature review on mechanical and feedstock recycling. The advantages and disadvantages of various recycling methods and their development perspectives are presented. The general characteristics of PVC are also described. In conclusion, it is stated that there are currently high recycling possibilities for PVC material and that intensive work is underway on the development of feedstock recycling. Based on the literature review, it was found that PVC certainly meets the requirements for materials involved in the circular economy.”
K. Lewandowski & K. Skórczewska, A Brief Review of Poly(Vinyl Chloride) (PVC) Recycling, Polymers, 14, pp. 3035, 2022
For comparison, paper can only be recycled between 3 and 7 times because the fibres are broken down with every cycle until they can no longer make paper of sufficient strength. We see it claimed that aluminium and glass are green because they can be recycled “infinitely,” but as mentioned, that is not true either.
In Norway, they recycle 60–70% of expanded polystyrene foam and are aiming for 90%. EPS is also recycled in large volumes in many other countries.
“In case the milk bottles are removed from the PE sorted product and they are mechanically recycled, a high quality of recycled HDPE can be obtained, which contains less contaminants than the freshly produced milk bottle. The composition of these contaminants is, however, different. In the freshly produced milk bottle only degradation products of HDPE and the antioxidant can be found, whereas in the mechanically recycled HDPE also traces of volatile contaminants are found that originate from the milk, the other packaging components, other packages and the surrounding atmosphere.”
E. U. Thoden et al., Volatile organic contaminants in HDPE milk bottles along the mechanical recycling value chain, revealing origins and contamination pathways, Journal of Cleaner Production, 459, 142571, 2024
The quality and purity are so high that several recycled plastics have approval for use in contact with food for which stringent testing is mandated. That includes the most common plastics, like PE, PP, and PET, among others.
What the Word “Recyclable” Means and Does Not Mean
The word “recyclable” is in the dictionary; it literally means “able to be recycled.”
This familiar symbol is used to indicate whether the material can be recycled.
Plastics are recyclable, and they remain recyclable, whether or not they actually get recycled. So-called environmental groups have launched legal battles over this. They asserted the customer was misled by claims that the product was “recyclable” when in reality, the probability that it would be recycled was low, even though both the dictionary and science say otherwise.
Whether something can be recycled is called recyclability.
Whether something is likely to be recycled in that particular locality is another concept and requires its own word, for example, “recycle-likely.”
Since so many people struggle with this idea, here is an analogy.
A football is “kickable,” and it remains kickable whether or not we choose to actually kick it.
I order food at a restaurant.
The food remains edible, whether or not I decide to eat it.
The same concept applies to recycling, where NGOs claim that the word recyclability actually means recycle-likely. Then, they complain that companies saying that products are “recyclable” are misleading us because the word is not being used according to their own made-up definition. If they want a word that means recycle-likely, then they should propose a new word and put that in the dictionary, not hijack another word and use that.
There is another flaw in the idea of labelling products with a recycle-likely symbol. What local authorities choose to recycle is up to them and varies widely. It is not possible to say whether that product is likely to be recycled where you choose to dispose of it. What if I buy it in Michigan, then cross over to Ohio and their government has decided not to recycle that product? The same applies to country borders. Many products are made in one country and sold in another, but somehow, the NGOs demand that the manufacturer become clairvoyant and anticipate the recycling policies of the region in which the product is eventually disposed. Sounds unfair to me.
Unfortunately, even the organisations responsible for recycling standards are adding to the confusion. Their goal is to make recycling easier for their members, so they also label non-ideal materials as non-recyclable. This is counterproductive and misleading. See the Association of Plastic Recyclers (APR) for specifics.
Is Plastics Recycling a Scam?
Lastly, some so-called environmental groups have made the accusation that recycling is a scam and that it can never work. We now know that to be false. Such groups are known to make up such stories to make people angry enough to donate — Dr. Patrick Moore, the former President of Greenpeace, said so himself.
Greenpeace wants a piece of your green – An independent report by Dr. M. Connolly, Dr. R. Connolly, Dr. W. Soon, Dr. P. Moore and Dr. I. Connolly, December 2018
There is room to improve, especially in the US, where rates are much lower than those in Europe, for example. For the US to catch up, the country needs better collection and infrastructure for sorting and recycling.
The Circular Economy for Plastics: A European Analysis, Plastics Europe, March 2024
Another reason that plastics recycling rates are lower than for some materials is to do with profitability. Expensive materials like platinum, palladium, and gold are terrible for the environment. For example, 27,000 kg of carbon dioxide are created for every 1 kg of gold made. Plastics are the opposite, i.e. they have a very low carbon footprint and are very cheap.
* around 50% of paper is downcycled into cardboard
Materials and the Environment: Eco-Informed Material Choice 3rd Edition, Michael F. Ashby, Butterworth-Heinemann / Elsevier, Oxford, p. 232, UK, 2021
International Energy Agency, End-of-life recycling rates for selected metals, April 2021
Being cheap means that people litter materials like plastic and paper, so collection rates suffer. Plus, it is not that easy to recycle inexpensive materials profitably because margins are lower. So, far from being a conspiracy, the lower recycling rate is at least partly because of economics. The price of recycled plastic fluctuates wildly, and companies frequently go out of business due to those swings. While plastic can and is recycled profitably, it is not trivial to make it work profitably in the long term. Part of the solution for that is for large companies to sign long-term contracts to buy post-consumer recycled plastic (PCR) at a fixed price. That way, the recycler can be assured of steady business. Another reason for the low recycling rate of plastic is the wide variety of plastic materials and the need to clean and separate the different types before recycling.
NGOs want us to use materials like aluminium and glass, which are much worse for the environment because they are more expensive and therefore more likely to be collected, with the profits from recycling them also being greater. I wrote an article to explain just how bad and illogical that idea is. If your friend told you to buy a Ferrari for $200,000 instead of a $20,000 Fiat because the trade-in value of the Ferrari will be higher when you decide to sell, would you fall for that terrible advice? I hope not.
Advanced Recycling or Chemical Recycling
You may have seen that there are huge, highly funded projects to create new types of recycling. These so-called advanced recycling methods, such as chemical recycling (breaking the polymer down into its starting materials), or dissolving the plastic in solvent, or pyrolysis, where the plastic is heated and converted into oils or monomers (the building blocks of plastics).
The perception is that we are waiting for advanced recycling to make plastics green, when in reality, standard mechanical recycling works just fine for about 90% of the plastic types we use, such as polyethylene, polypropylene, PET, and PVC. These other more expensive, more complex approaches to recycling may eventually have a place in the future, but they are not the key to success.
L. Veillard, Fifty years: chemical recycling’s fading promise: Industry Landscape Overview, Zero Waste Europe, November 2024
Mechanical recycling is proven to be cheap and the best environmentally speaking. Plus, it uses standard machinery already installed all over the world because those machines, called “extruders,” are used to process new plastics too.
These more difficult forms of recycling may have a place for the minority of plastic that cannot be mechanically recycled and for plastics that have been mechanically recycled repeatedly until their mechanical properties have declined too much. Even then, however, it may make more sense simply to burn the plastic to create electricity, replacing the need to burn oil, coal, or gas, thus saving fossil fuel.
T. Uekert et al., Technical, Economic, and Environmental Comparison of Closed-Loop Recycling Technologies for Common Plastics, Sustainable Chemistry & Engineering, 11, pp. 965–978, 2023
Pyrolysis is a Green Way to Recycle Plastics
What about pyrolysis as a way to deal with used plastic? Life cycle studies on pyrolysis reveal that it does not make environmental sense.
Pyrolysis means heating substances without oxygen to convert them into organic liquid or fuel, but plastics are already as energy-rich as oil or coal.
Solid plastic waste can be burnt to create electricity, thus reducing our need to burn fossil fuels like oil, gas, and coal. So, why use pyrolysis to turn solid plastic fuel into a much smaller quantity of liquid fuel? Think of the analogy of changing money. If I have a dollar bill and ask for change but only get 50 cents in coins for my dollar, that would be a terrible deal. That’s the same deal on offer with pyrolysis.
“The catalytic pyrolysis of PS produced the highest liquid oil (70 and 60%) compared to PP (40 and 54%) and PE (40 and 42%)…”
R. Miandad et al., Catalytic Pyrolysis of Plastic Waste: Moving Toward Pyrolysis Based Biorefineries, Frontiers in Energy Research, 7, 2019
Pyrolysis is not green and is only researched because people take government money, meaning our tax money, to do it.
The same for other approaches, like dissolving the plastic in solvents or using enzymes to break the plastic down into new monomers. While technically feasible, these methods usually turn out to be red herrings when one considers the investment needed and the impact of the process itself. Why then are there so many headlines and projects on them? That’s because people will do whatever they can get funded to do, whether or not it actually makes sense. Some have criticised attempts at advanced recycling, and they have a point. Spending time and money on technologies that do not make sense only increases environmental impact.
Summary
Like all materials and everything we do, plastics have an impact. However, decades of life cycle studies agree that plastic is almost always the alternative that minimises material use, waste, greenhouse gas, fossil fuel use, and total impact. Recycling works and rates are high in many countries; the USA is anomalously low and working to improve. Mechanical recycling is cheap, proven, and works with existing equipment. Let’s be wise, which means picking the option that minimises impact, then reuse and recycle it.
We have learnt that the more impact a material has, the more expensive it is, and therefore, the more economically attractive to recover and recycle it is at the end of use. Such high-impact materials may be attractive for recycling, but that is not a reason to choose them. We are told to choose aluminium cans because their recycling rate is high, but that argument is false, though promulgated by companies trying to sell you a product. On the contrary, the wise choice is the material with the lowest environmental impact, and in most cases, that material will also save the customer money, as well as saving the environment.