Chemists tackle the tough challenge of recycling mixed plastics | Hacker News Reader

Chemists tackle the tough challenge of recycling mixed plastics

phys.org

116 pointswglb119 comments

In some cities garbage workers are intstructed to take a look at a recycling bin beforehand. If they see a single plastic bag they dump the whole thing with the landfill pile. Same for "compostable plastic bags". Bags break really expensive machinery regularly and are probably one of the single worst things you could throw away

There are so many gaps like these in the public's understanding of how recycling works (and doesn't!) and the reality. Mixed plastics are useless; you need to wash your dirty plastics; the triangle doesn't mean it's recyclable it's there to tell you what type of plastic it is (usually only 1, PET, and 2, HDPE, are recyclable). These are the very basics of recycling that, from my experience, the majority of people don't understand. It would take literally 10 minutes to explain most of this to people

We keep bending over backwards trying to innovate our way towards making recycling really behave like the magic green plastic/paper eating box people imagine it to be but I feel like we'd get so much more return on investment if we spent a fraction of our investments on simple public education. At least at this point where that latter investment is basically nil in most places

Educating people to spend time solving themselves a problem over-and-over forever, versus expanding our knowledge of material science to solve that same problem for everyone, once and for all?

I know which one's preferable.

(Is it either/or?)

It's not one or the other. It's that we're spending millions into one category and zero in another.

Zero waste is already technically achievable with the technologies we have today. Kamikatsu, Japan is an extreme example where they sort their waste into 34 different bins.

We don't have to do all that but we would see extreme immediate benefits from even slightly abandoning George Bush's "the American lifestyle is non-negotiable" proclamation

The sorting doesn't really work as odds are too strong that someone in the city made a mistake and so you have to resort everything anyway. Automatic sorting machines that don't make mistakes are a better bet in the long run.

Don't forget to account for the costs of 34 separate dumping operations, generally with 34 different trucks, which is itself and environmental disaster.

This is because recycling is a fraud whose primary goal is to make people overcome their opposition to consuming wasteful plastics.

This—it’s a tactic to alleviate guilt from the consumer for buying single use plastics. The best education is to let people know that the vast majority of plastic will not be recycled.

My motivation to recycle and sort took a big dip when I found out that where I previously lived the plastics bin gets carted off to incineration, all of it, no recycling in place because apparently that wasn't economically viable.

That should really be said of "biodegradable" or any -degradable.

Plastics are pretty much an optimum in terms of energy required to produce vs. durability, so deliberately decreasing the latter is the real waste and the result of an agenda of planned obsolescence.

Plastic recycling certainly is. Not sure about other materials. Plastic recycling is a scam from the petrochemical industry though and doesn't work.

I understand the sentiment but it's not a solution. The only solution is to prohibit plastic packaging or force companies to use types of plastic that are easy to recycle. I believe it's easier to regulate the company producing the waste than try to get the entire population to agree on and behave in a certain way.

True but there would also be more public pressure to regulate if people knew just how little of their recycling actually gets recycled.

https://epr.sustainablepackaging.org/

As is standard, perhaps, the concept and ideas are already well-established, the only requirement is to enact them. I also suspect that many of the initiatives are pretty weak, watered down by packaging producers who don't want to bear the full cost of waste management.

Why should we not try to get the population to behave a certain way? The alternative is a society full of people who behave antisocially, acting as if only their needs matter. It’s hard to say whether a concerted effort to make people more invested in the civic good will be effective, but throwing our hands in the air will undoubtedly have the intended effect.

Because changing one thing that has a huge impact (the manufacturer) is a lot easier than changing hundreds of millions of things with each a tiny impact (people's habits).

"It's hard so don't try."

How about, instead of doing the almost-impossible thing that is not necessary or logical (why should everyone else change in order to offset lost profits for a company that doesn't care about them?), do the easy thing that is practical and rational.

Or you can decry society for doing the easy thing, but remember that trying to shape outcomes when dealing with large numbers of people almost always leads to consequences that seem obvious in hindsight but were unpredictable at the onset.

FWIW in Washington state where I live (and in the 3 cities/towns I've lived in here), multiple times a year Waste Management/WM sends out a flyer explaining what can and can't be recycled. It changes over time and it's extra confusing because the recycle cans have different rules printed on them than what is in the flyer. We used to be able to recycle juice boxes and milk cartons, no more. Then we were supposed to recycle glass jars and their metal lids, but now "no lids of any kind." We were told to flatten and recycle all paperboard boxes, but now we are supposed to skip recycling any paperboard boxes that have a clear coating on them (every freezer box, according to their instructions). Plastic bags have always been prohibited. But of course I see my neighbors putting plastic bags in their cans all the time. There are so many rules about what plastics can be recycled that I can't even remember them.

I think the "education" aspect has been attempted and it's not working. It's time to go nuclear and have the government dictate what types of materials can be used for packaging and ban everything else.

If I never see another blister pack it will be too soon.

I feel that this has things inverted. People generally don’t care about the packaging or even the materials in the product. Those choices are made almost entirely by the seller.

Why should the buyer be responsible for cleaning up the seller’s mess?

If it’s possible to economically create products that don’t produce waste then this should be mandated, because otherwise there will always be some asshole corporation who is willing to undercut competitors on price by externalising costs to the environment.

"Getting buyers and sellers to both behave responsibly is mutually exclusive."

I can't speak for other countries, but in the US trying to get everybody on the same page in terms of recycling habits would be worse than herding cats.

It's not something anybody wants to put energy towards because they're trying to keep 50 other plates spinning at any given time (which as an aside, is also a huge source of plastic waste because nobody has the time or energy to cook) and there's also a chunk of the population who will take any kind of push to change behavior as a personal affront.

You can probably get a small percentage to adhere fully and a slightly larger to partially adhere, but I agree with parent comments that it's better to make companies use materials that are easier to recycle in the first place.

I don't disagree with what you're saying, but it isn't mutually exclusive with having the government do what it can do educate the public in order to get them behave more responsibly and civically minded. Obviously this would require a bit of a re-think in terms of what we value as a society. Doesn't mean that it isn't worth trying.

The plastics lobby argued in favour of single use plastics many decades ago, and that's where the focus on end consumer responsibility comes from. These were literally the same PR firms that used those same tricks on behalf of the tobacco industry not long before that.

Putting the onus exclusively on the end consumer is the easiest way to ensure the industry doesn't bear the burden and expense, and that's entirely the point.

I am not advocating that we put the onus exclusively on the consumer.

This is a controversial position, but: Because technology exists for all product packaging to be made from single-process-recyclable/biodegradable materials and only using plant-based ink we could force companies to use it. This would drastically change the marketing landscape and make it much less shiny but everyone would be on the same level field and consumers would adapt.

The other way is to reuse very inert materials like stainless steel or glass. Outlaw all the silly marketing designs and make them standarized like shipping containers and buy them back from the consumer. It used to work this way before plastics came along anyway. Beer and milk bottles would be swapped for instance.

Right now we have 4 items we can basically recycle.

Glass -> fairly straight forward to recycle Metal -> fairly straight forward to recycle Paper -> depends and very water intensive but kind of OK and not totally terrible if it is just burnt. But nearly as all over the place as plastic. Plastic -> All over the place and dozens upon dozens of differing types rules regulations and depending on your local area how much is actually 'recycled' (a lot less than you think)

Then on top of that we are to reduce, reuse, recycle. The manufactures have skipped the first two steps and blame us for it.

Plastic is the worst of them to recycle it has the least recyclability. I have seen estimates from anywhere for 5% to 10% of the total plastic stream. Then customer shaming and deceptive tactics to make me feel bad for this. The bottom line is plastic is the worst for recyclability yet we use it for a good portion of our containers. We are worried about plastic straws and yet a good portion of the food I buy comes in a plastic container. Instead we should be putting pressure on the upstream to give us containers that they and we can reuse.

It's worth separating out the packaging waste in statistics e.g. if you buy a plastic doll in plastic packaging, the doll might account for most of the plastic.

If you buy a plastic lawn chair there may be no packaging, but still a sizeable lump of plastic.

Plus global averages hide variation in package recycling (and reclamation) rates are surprisingly okay in developed nations, even in the US which you'd think is culturally incapable based on the anecdotes you hear. It seems like big cities where lots of people live are doing better than less dense areas where relatively few people live, which keeps the stats high.

See historical graphs and charts here:

https://www.epa.gov/facts-and-figures-about-materials-waste-...

> ...or force companies to use types of plastic that are easy to recycle.

And code them in such a way that allows easy automatic sorting, say by requiring type-specific colors (e.g. PET is allowed only certain shades, and HDPE different shades, etc.).

You have to assume that any adherence to a recycling regime will have a spectrum of success never reaching 100%. Someone will fill their bin with all kinds of non-recyclable plastic. They won’t always clean them out. Education can improve this situation but it can’t eliminate it. We have to assume failure at some level and design for it instead of chasing the unattainable 100% compliance.

In the office I work with smart tech people, I see mistakes all the time. You basically have to read the entire recycling guide to get it right. So yes, it has to be built for 90% compliance.

In Switzerland they have a “simple” solution to this problem. The onus is on the consumer to make sure all recyclables are washed and split appropriately. There are different bins for metals, paper, compost, and the different kinds of plastic. The municipality randomly checks your bags and fines you if you don’t do this right. Regular trash has to go in specific bags that are much more expensive.

Basically the incentives are setup such that everyone takes the 10 extra minutes to do it right. People are annoyed but once you have a system down it’s not really hard to do.

I think this is the way to go. Everyone pitches in to make recycling work. In the long run it may even incentivize sellers to make their products easy to recycle, as buyers are forced to care.

Note I may have some details wrong as this is based on what I remember from living there 10 years ago.

“ Everyone pitches in to make recycling work. In the long run it may even incentivize sellers to make their products easy to recycle, as buyers are forced to care.”

I just bought about 15 pounds of plastic in the form of bottles and material and whatnot from the store. Then at the front they refused to give me plastics bags weighing a few grams.

There’s no way in hell any reasonable person should be on board with these kinds of taxes or policies. All they will end up doing is making people pay money to the rich, while the rich don’t do anything but continue to use more plastic for their purposes

You want change, charge the company for plastic straight away. Stop expecting consumers to bear the burden of corporate greed

Hear hear. And even then, plastic grocery bags are part of a beautiful, closed system of becoming trash bags. Now I have to go to the store, buy a literal roll of plastic bags, and carry it home in a non-plastic bag, then throw my garbage in this one-time-use garbage bag.

Congratulations! Progress has been made at you.

Do you have to use bags or do just do it because you've always done it?

We have similar recycling setup in Germany. I don't use bags for any of them.

We are not allowed to throw trash without bags for obvious reasons. I'm not sure I understand what you even mean by that.

What are the obvious reasons? Doesn't your trash go in a trash can?

Where do you empty your trash can?

Let’s say you throw away something sticky, maybe a dirty diaper, or something else. You don’t want to get that stuff on your own trash can, and the garbage collectors don’t want to deal with soiled garbage bins either. It is simply about sanity, residues and stuff attracts rodents and other pests.

Both in apartment buildings and in houses with trash collection, the rule is that you put the trash in bags.

All buildings have larger bins (between 240 and 1100 litres) on the outside or in a specified area. Those are picked up by the waste companies. There is no need to specifically place waste into a bag. You can just put it straight into the container.

We generally don't have all that much super sticky trash. We also simply clean our bins when needed. Our organic waste bin, for example is simply lined with an unbleached kitchen paper towel that gets dumped into the container as well.

Where I live, the large trash bin is collected by a small company that sends non standardized trucks. The workers open the bin and manually empty it, one bag at a time, by hand.

Not everyone lives in a big city. I'm not sure what I could put my garbage in to make their job easier other than some sort of bag. Find me a non-plastic bag that can fulfill this purpose and we'll have a reasonable solution. But since there is literally no other trash collection game in town, for now, the bags stay. I'll find other ways to reduce my plastic consumption, but I don't expect to fully eliminate it.

That sounds tedious.

Part of the solution to that is to standardize it. Even outside of cities, the bins are the same and can be picked up by the trucks automatically. The only manual part is rolling it to and from the truck.

Of course, generally usingess plastic is always the better option.

Just in case your request for a non-plastic bag was a real one, you can buy large strong paper bags for yard waste at home improvement stores.

I live rurally in the us, and don’t use trash bags at all. Our trash trucks pick up the bin and dump it into the truck rather than unloading in manually. I have noticed more roadside trash on trash days, because of unbagged trash.

The implementation of this was interesting in Switzerland. Because consumers had to pay a lot for waste, they started to remove packaging at the store and dumping it there for the store to deal with. Stores had the cost of removing packaging waste and put pressure on the supply chain. If customers start removing toothpaste tubes and cereal from cardboard boxes and dumping it the store's door, then the store has to deal with the overproduction of waste.

Take the habit of putting bags in your car, reuse them. It takes a while to have a system but now I have bags in my cars, a bag in my work backpack, etc.

I don't need any plastic or paper bag ever and additionally, my bags are much nicer and much more heavy duty...

I've spent a few months in Switzerland in 2020 and all I've seen were PET and non-PET bins for plastics.

But the rest of the world has that already in the form of public bins for plastic bottle caps, as these are made from PET.

In any case fines or no fines I doubt this is enough if a single piece of trash can ruin a whole batch.

I can assure you that I for one have thrown trash in the wrong bin at least twice - or maybe more because I still don't know the details of recycling in that country.

Sounds like a regressive tax to me - rich men can pay sorters to avoid ever wasting their own time on recycling, poor men who can least afford the time and effort and fines if they get it wrong meantime suffer under the system.

Much better approach would be tax-funded recycling sorters - much more cost efficient to do all the work at the point of collection besides, allows for training and specialized equipment.

Austria is kinda the same way. We had to sort everything into one of 6 bins. But there was only one bin for all plastics.

The 6 bins is fine (metal, glass, paper, organic, plastic, landfill), further sorting the plastics into the 7 kinds currently labeled might be a bit much (especially since only like 3 of them are commonly recycled).

I was curious about how they solved the mixed plastics problem, and quick searching around suggests most of the plastic gets incinerated.

There are containers for recyclables where you personally dump your bags brought along, so there's no bag for the municipality to check. You maybe mix this up with the fine for using non-fee garbage bags? The only check they can do is when looking at your recycled paper stack whether it has also cartons, then they'll leave it on your roadside (and if you're around they'll also tell you why). But that's hardly noteworthy.

In any case, Swiss shops are starting to take in also the new category of "non recyclable plastics" as in non-PET wrappings/recipients/tetrapack/anything. No idea where those go though, I never thought to check if they're burnt or exported.

but I feel like we'd get so much more return on investment if we spent a fraction of our investments on simple public education.

For a great example of this, look at Japan.

Bags break really expensive machinery regularly and are probably one of the single worst things you could throw away

I've seen dedicated bins just for recycling bags, but as you mentioned, the problem is in educating people to sort plastics correctly.

Of course, reuse comes before recycle, and lots of things that are supposedly "single use" can really be reused instead of buying something else, but many people don't even bother to think.

In the UK, supermarkets have bins for recycling plastic bags. Not just shopping bags, plenty of plastic packaging is labelled "recycle at supermarket".

Empirically, most people weren’t willing to do this stuff (the kind of education you’re talking about was common in early recycling programs) and recycling only became widespread with the advent of single stream. Maybe advocates just need to try harder, though.

> Empirically, most people weren’t willing to do this stuff

People had to be taught to throw things away. Seriously, just look at vintage 1950s advertisements introducing the concept of "disposables."[0] This was commercial and government interests aligned on what to do about all the production capacity and factories from the war economy now that the war had ended. The conclusion was a total transformation of our society centered around consumption

I think it's important to bring some historical context and remember that what needs to happen here isn't so much "learning" as it is "unlearning"

[0] https://www.huffpost.com/entry/vintage-ads-plastic_n_5cdb176...

I remember a scene in the show "Mad Men" where they just flick out their blanket to scatter all trash from a picnic and then leave. I thought it had to be satire but I asked an older coworker and he said it was pretty accurate to how things were when he was a kid.

Ironically, plastic bags were invented to be reusable.

The term "disposable" might be a post-war thing (The Google Ngram views for "disposable" https://books.google.com/ngrams/graph?content=disposable&yea... and "disposables" https://books.google.com/ngrams/graph?content=disposables&ye... are pretty neat.)

However, the concept is older. One-use paper Dixie Cups started around 1910, replacing the shared cup.

"How unsanitary!" you might think of the old system.

Sure, but the Dixie Cup Company sure did promote that hard. "Just think of the luxury—a new cup filled with pure water all for a cent" - https://journals.sagepub.com/doi/pdf/10.1525/ctx.2010.9.1.73

One of the things I’ve seen at universities a lot are signs on the recycling and garbage bins saying what is allowed and not. Maybe recycling bins could have more of that to help people know what’s okay or not.

Do you think it’d help if the plastic type label was color coded too? Say yellow for PET, red for HDPE, etc, to help people recycle only the right plastics.

Generally I’ve seen that it’s not that people don’t understand recycling, it’s that it takes energy and effort to figure out what to do and it’s not always easy.

I live in a nice condo building. Every floor has a recycling room, with a sign above the two bins that says "no bags, put recyclables directly in bins". I still see a lot of bags.

I think there just needs to be someone supervising saying "For real, seriously, no bags." I think people just don't know if it's a real rule, or an over-simplified kinda fake rule, like wear a helmet. In fact, I don't know, I just have a weird engineer mind that wants things to work right, whatever they are.

Actually I think we need people to be told, in school and at recycling points: "you don't have to pretend to be green, just throw it away if you don't care". It seems to me that recycling is one of the least controversial things, everyone knows it's good and wants to support it, just not many people evidently care that it's done in a way that actually works. Again, as an engineer, this bothers me.

The Precious Plastic project shows how to recycle plastic grocery bags into a polyethylene feedstock to manufacture new objects with [1]. You can also turn grocery bags into 3D printer filament. The technology is within reach of intentional communities to maintain, so they turn what is usually a waste stream into an asset.

[1] https://community.preciousplastic.com/how-to/create-marble-f...

>> wash your dirty plastics

I've thought about this a lot. Is it worth wasting water, derergent and energy to clean a yogurt cup, for instance? Does the plastic-waste-recycled outweigh the water-wasted? I never found an answer, maybe this is a really tough comparison? Too apple vs. orange? (Edited for spelling)

Especially if my clean plastics will get mixed in with a bunch of dirty plastics and then rewashed in with that batch. I don’t know the answer either but would love to find out so I can be a better citizen about it.

The CO2 impact of potable residential water in most places is minimal, about 0.22g/liter [1].

[1] https://www.danfoss.com/en/about-danfoss/articles/dhs/the-ca...

If CO2 is the concern, wouldn't sending that plastic (carbon) to a landfill (sequestering) be even better?

No, basically all Lifetime Cost Analysis of plastic recycling suggest it saves carbon/GHG to recycle. (And further that incinerating it with energy recovery is more GHG friendly than landfill)

The people who believe otherwise seem to get their information from fossil fuel funded "libertarian" sources, that seem to magically always conclude that selling more fossil fuels is the best possible answer to every question.

Your yogurt cup is almost always PP (Polyproylene) Type 5 to maintain stiffness at large size. In that case the answer is throw it in the garbage, they're going to burn it or send it to China/Africa anyway.

The one that blows my mind is washing aluminum cans (or steel). How do you think they're going to get the plastic coating off the cans and remelt it?

I mean don't recycle a full can, but they have washers for recycled materials too.

> The one that blows my mind is washing aluminum cans (or steel). How do you think they're going to get the plastic coating off the cans and remelt it?

> I mean don't recycle a full can, but they have washers for recycled materials too.

I'm sure they have washers, too, but how well will they work for sticky, dried on stuff?

Also washing helps prevent the bin from getting smelly.

It all ends up as slag when smelted

You should never wash any trash. Either it is recycled properly and it is washed in highly efficient manner or it isn't and washing doesn't matter.

Looking at it from the other perspective - the trash is rarely worth even the few seconds of the time you spend washing it.

I don't know how it is in other countries. We recently wondered what the right thing to do is and the Citystate of Berlin has an FAQ on recycling: https://www.bsr.de/die-top-13-mullmythen-26874.php which makes some things explicit:

(It is in German, but deepl translated the relevant section)

Do empty bottles and packaging have to be washed out?

No. Because the packaging is rinsed out in the recycling process, when the sorted plastics are shredded. It is only important that all packaging is emptied of residues [ed. The translation misses tmthat they mean large residue or levtover amounts], is not stacked and the lid is removed.

Recently, I was at a local shopping center, and there were trash bins with the usual three color marked holes for recycling ... but under them, if you peeked close enough, you saw there was one collecting bag where everything went. Made me sad.

This is the wrong attitude. This is victim blaming. Expecting ordinary people to understand the bewildering array of plastic types, biofilms and composite materials is not realistic. Add to that deceptive packaging (like the infamous green triangle that doesn't mean it's recyclable at all). The solution is to tackle it at the source of all this waste. Tax the shit out of supermarkets and shops that sell non recyclable packaging.

I think you're posing a false dichotomy here. I, as a person who is still fuzzy on how to recycle, did not feel blamed. I agree with the general sentiment; nobody knows the rules! We should've had a whole class on shit like this in high school. Obviously, there are larger problems caused by unfettered capitalism at work, but increasing recycling and composting infrastructure, hand-in-hand with public education on how to use that infrastructure, would make things better, and probably add some intangible benefits, like feeling some degree of agency over the process, which would have positive externalities like making people feel like they might have some greater agency over the bigger, structural problems, which might lead to greater political/economic change.

> In some cities garbage workers are intstructed to take a look at a recycling bin beforehand. If they see a single plastic bag they dump the whole thing with the landfill pile.

I once saw someone throw a couch away in the recycling bin...

Seems sensible, wish they did that here so I didn't have to keep moving dirty bags between bins.

I recycle correctly but one apartment in the block is being used as an AirBnB, every week there is random waste in every recycling bin.

in Britain we have 100 different municipalities and all of them differ in their recycling policies and capability

> you need to wash your dirty plastics

Funny, I heard the exact opposite in a documentary about one of these recycling facilities, from the people running the facility. They should probably know. Though it may also very much depend on the facility itself.

As someone who actually knows this stuff, effectively sorting my trash is way too much effort for effectively very little return as I also know chances are even if I do it right my stuff will be burned anyway.

It is completely unrealistic to expect the average trashbin user (as in literally everyone even if you can't read) to follow recycling instructions for plastic (paper tends to be simpler). It's much too complicated and a majority of the packaging you'll find in supermarkets involves way too much effort separating the materials.

Why is it unrealistic?

Is it reasonable to expect every important problem or social responsibility to be easy or unobtrusive?

Sometimes you may both need to do something and it's inconvenient...

It’s all theater and not worth doing, we should recycle metal, glass, and paper and burn/bury the plastic. We might as well be honest with ourselves about where our waste goes instead of pretending we recycle it.

I think all packaging material should be taxed by weight, but with a multiplier that corresponds to the amount of that type of material which is actually recycled. Glass is heavy, but the data shows that 90% of it is recycled? The tax is 90% off.

This would do three things:

1) Encourage manufacturers to use materials which are actually recycled. 2) Encourage manufacturers to reduce total material. 3) Encourage manufacturers to invest in new methods of recycling to move the multiplier in their favor.

I get taxing companies for things that cost taxpayers money, but why do this based on recyclability? It seems like more of an economic problem: if recycled plastic costs more than new plastic, then why is it better? Charge companies for packaging that ends up in the landfill instead, otherwise these companies are essentially being subsidized by taxpayers to package things however is more profitable without having to account for that cost.

Yeah, the tax should reward companies that reuse their packaging. Glass bottles are east to clean and return for reuse, but we stopped doing that nearly 100 years ago.

At most 40 years ago. I remember turning in our used Coke bottles at Heinen's for the bottle deposit back in the late 1980s in Cleveland, OH. You could tell the reused bottles by the distinctive white chipping pattern around the raised features.

Where I live in western Canada there's still some regional dairies that have reusable glass bottles (they even put the year the bottle entered circulation, they seem to last several years pretty easily).

In Denver, there's a dairy that still does morning delivery in reusable bottles, albeit plastic.

The model still seems to work fine on a certain scale.

The end started about 100 years ago. Some companies held out for many years longer. 40 years ago there was already a lot of plastic, though I'll admit to not having a better timeline

Norway reused plastic bottles until sometime last decade (now we only recycle) and I think that in my childhood in the 80ies we reused glass bottles as well, but I am not sure about that last point.

At my store the same size/type of olive oil comes in plastic bottle or glass bottle and the glass bottle is a dollar more expensive.

Taxing the consumer and forcing that tax to be in the advertised price-point would do wonders. Would leverage capitalism to drive packaging waste reduction. Doesn't even need to be a national thing, if just the state of California implemented this it would drive reductions nation-wide.

It was a bit confusing, but when I said "amount of that type of material which is actually recycled", think I'm agreeing with @surement: look at the amount of material in the actual landfill stream vs the recycle stream. If studies show that overall, 1% of plastic is recycled and 99% goes to the landfill, then all plastic material in all products will be charged at 99% of the tax rate. The incentive here is to encourage companies to develop technology to move the recycle rate from 1% to 10% to 50%, etc. Adjust that discount quarterly or annually or whatever.

Plastic would still win in this case. It needs to relate to the environmental cost of production and disposal.

Plastic separation can be done using in-flight air sorters coupled with multispectral imagers and neural net AI systems.[1] San Francisco's recycling plant at Pier 96 has had optical sorters like that since 2016. This is installed, commercial technology. It's fast, too. "In the time you were watching this video, the systems sorted 6,000 bottles."

In flight air sorting with cameras and AI has huge capacity. Most vegetables pass through such sorters. It's even used to sort individual grains of rice.[2]

Interestingly, when the biggest plastic bottle recycling plant in California went bankrupt, it was bought by DAK Americas. DAK is a plastics manufacturer. They make PET for making bottles. That they bought a bottle recycling plant indicates the round-trip process has become profitable. Now they have a raw material supply that isn't tied to the price of oil.

This proposed chemical process is not separation. It's linking incompatible plastics into a new bulk material. But what do you do with that? It's not suitable for containers.

[1] https://www.youtube.com/watch?v=wpGGHUaoo0Y

[2] https://www.buhlergroup.com/content/buhlergroup/global/en/pr...

We should just bury plastic in a nearby modern landfill.

Plastic comes from oil, and putting it back into the ground is probably one of the best things you can do with it from a CO2 point of view.

Spending fuel etc transporting it to be recycled is just a waste.

agreed. why are we washing and transporting plastic. just bury it and if it’s worth something later dig it up.

Or burn it until all thermal power plant must be shut down.

Consumer plastic use isn't a big CO2 producer.

Thing is, nothing is a big CO2 producer on its own. It’s all small percentages and little bits of percentages. But there is so much going on in the world, that it adds up to a big problem.

Not really - transport is huge, heating is huge

Platic is more of a pollution issue, not CO2 issue

Or burn it for peak energy generation. Better than burning oil/natural-gas as this at least gets two uses from the oil 1) As packaging, 2) As peaker-plant energy source.

I always wondered why is there no regulation which limits the amount of plastic types that can be used - especially in packaging.

Soft plastic - one type. Hard plastic - second type. Is there a need for more?

This ship has now sailed I guess, with the amount of plastic that is in circulation - but limiting the number of types allowed for use would (to my mind) simplify and facilitate the development of effective recycling programmes

There is, in California and other such places.

They try to avoid "picking winners" by stating a specific type of material, but the law states that whatever you use has to be accepted in most recycling centers and actually recycled to a specific percentage of output.

This effectively bans the stuff that isn't recyclable, but lets each producer make their own individual choices.

https://calrecycle.ca.gov/packaging/packaging-epr/

https://calrecycle.ca.gov/packaging/statefoodservice/

It's interesting to read the replies in this thread because a lot of people are proposing alternative "it's just this" solutions to the same problem being solved here -- the over abundance of plastics.

But the solution can be all of these proposed "it's just this" strategies combined.

We do need a: - standardization of plastics, - a switch to alternative materials that are more compostable, - a research lab to more deeply understand the true nature of plastics and their reuse, - a tax on environmentally costly materials such as plastics, - depolymerizing, - and more...

These are all solutions to the same problem. Let's work on all of these problems simultaneously and combine them for compound effects.

In a world with finite resources, and capacity to care prioritization goes a long way. This is why a huddle of engineers is just chaos sans a Product manager.

If packaging is made from non-recyclables a seller should be forced to take it back from a buyer.

That way the packaging always ends back up with its creator.

I keep thinking thermal depolymerization is the only good strategy for anything not standardized (soda bottles, milk jugs). Plastics are just too cheap, light, and durable to move away from in a lot of applications that they won't go away, and a lot of these are the applications where they're hard to recycle. That leaves burning, burying, and depolymerizing.

> Plastics are just too cheap, light, and durable to move away from in a lot of applications that they won't go away

There's an easy answer for this, build the externalities into the price. They won't be cheap, and so alternatives will be used. Depending on the kind of plastic, of course, the externalities differ, and thus so too should the price.

The alternatives have their own externalities. Paper comes from monocrop plantations (so soil depletion and erosion,and after heavy rain, trash all over roads and neighboring properties), and it's energy intensive and chemical intensive to make. The waxes used for foodproofing paper are-well, you might as well just use all plastic.

Glass is very energy intensive to make and it's heavy to transport. Aluminum is also very energy intensive. It's the best in terms of recyclability though.

Yes, don't get me wrong, we should incorporate the externalities of all package manufacturing. Hell, all manufacturing generally. I think if you manufacture it, you should be responsible for disposing of it.

Doesn't this research present a very attractive fourth option, if it's successful?

There will be a need for chemical fuels to burn to tide over dark/calm periods from renewables. So why does plastic, or waste paper for that matter, need to be recycled? Just treat it as fuel that temporarily served some other function.

What would be needed here are regulations to keep the waste plastic from containing stuff that screws up its use as fuel.

> So why does plastic, or waste paper for that matter, need to be recycled?

I researched what it would take to acquire our own plasma gasification to burn plastic among other waste streams for a true zero waste footprint community. It turns into a very complex system to prevent undesirable particulates like dioxins and furans from dispersing into the atmosphere when burning plastics, especially mixed plastics streams. The inert vitrified glassy rock has a far lower economic value per kg than if the plastic was downcycled into manufacturing feedstock. The maintenance on the systems was intensive and expensive, so between capex and opex, a community already consciously downcycling plastics back to feedstock would have to be quite large (>10K) before a plasma arc with heat co-generation plants would be economically prudent.

So this universal dynamic crosslinker is a welcome advance if we can use it to create upcycled feedstock in bulk. I see burning as a last resort; we should want to preserve the embedded energy in materials as long as possible in circular use and use the least possible increased embedded energy into them when transforming them again. It is much more economically efficient modeling the use pattern in this manner.

There should be only 2 or 3 types of plastic allowed and they should all be recyclable. Single use plastics and non recyclable plastics should be outlawed. I don’t care how expensive that makes things. We need to recycle our plastics instead of burning them like we do today, after china refused to take out plastic which they later burned.

Here you return your bottle to the store and get 15-25 cent for it.

Sorry for stating the obvious but it's not a challenge to do this with all packaging.

They are trying to cure our unwillingness with chemistry which is a noble effort but only if you're a chemist yourself.

this is impractical for retailers with limited storage capacity - groceries use their shelves as storage and don't have "back rooms" to storage additional material.

also, reverse logistics is impractical for grocery delivery.

These days, here in Norway, every bottle is flattened or chipped as soon as it has been recognized and sorted by the rvm machine in the shop.

Also key actors in the system are rewarded (or maybe punished less?) based on recycling percentage.

It's funny how we had standardized on glass for the longest. There a countless other standards across almost every industry we can imagine.

What makes plastic so special? Aside from being a byproduct of Big Oil's product?

I'm glad that chemists are researching this. We should also stop using plastic wherever possible.

Let's start with single use packaging of things. WAY too much stuff relies on cheap, disposable plastic that could be shipped/packaged in another, more sustainable material. It will mean more expensive, harder to handle materials, but if we can at least use materials that biodegrade, are fully recyclable, or are inert (e.g. glass), we'll save future generations a massive headache.

Polymers, also known as soft matter, degrade very rapidly when exposed to high temperatures (e.g. melting). I don't see how anyone would be able to engineer their way out of that issue in the next 5-10 years.

Enzyme action on plastics

This sounds a little like Licella's CaT-HR technology for breaking down different plastics into compounds that can be used as industrial inputs.

It felt like what it does is make a higher order polymer, which itself was useful. So, its making feedstock for "more" plastic but not the specific polymer chains of the inputs, or feedstock to make them.

A bit like if there was a mixture of plasticine and play-doh, and what you get out is a composite of both chemically, which it turns out makes lego bricks.

At least thats how I skim-read it.

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