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Sorry for a silly question, I'm sure it was asked many times in different forms but I wasn't able to find any concrete answer so here we go.

So, I'm trying to understand what is the 'best' way of getting rid of plastic waste and all options look kinda bleak.

  • Recycling is very hard due to sorting and contamination and plastic can't be recycled endlessly (and total energy spent is very hard to calculate due to high amount of manual labor)
  • Clean burning releases CO2 and also requires a lot of energy, possible a lot of extra fuel
  • Chemical recycling into liquid fuel is nice but this fuel will be burned and CO2 will be released as well

So, why not store it as-is? As I see it, the biggest problems with landfills is:

  • Smell and general decay, which releases methane
  • They take a lot of space
  • Garbage may heat up and burn or blown away by wind, birds and animals may eat it
  • General leakage into the surrounding ecosystem, ground water and so on

Okay, so why not do it a bit more specific? Plastic by itself is very resilient, it doesn't decay, smell or catch fire, it doesn't produce radiation. It won't smell by itself or produce methane. So it can be stored in like, a concrete cave or just in a big warehouse, we just need to separate it from organic waste and protect from wind/rain/ultraviolet. It can be done with minimal sorting, without separating different kinds of plastic or even glass or metal.

In the end all this hard garbage will just sit there and.. like.. do nothing? Its carbon contents won't be released into the atmosphere, it shouldn't require a lot of care. Sure, it will take a lot of space (although we can build skyscrapers for that purpose, lol) but that's kind of it? Sure, it's a bit sad that we can't use it again but looks like it can't be done efficiently anyway.

And it can sit there until humanity comes up with an efficient way of using it again or until it becomes a new oil for the new sapient species that comes after us :D

So, what am I missing here?

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  • "so why not do it a bit more specific?" -> because it costs more than a landfill
    – njzk2
    Nov 25, 2022 at 22:58
  • Sure, but recycling costs even more. Any kind of garbage management will cost money, it can't be profitable by itself (at least, right now) so it's always backed up by some kind of government incentive
    – Amomum
    Nov 26, 2022 at 22:10

4 Answers 4

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Inconsequential. Plastic wastes are largely inert. Stored in landfill pose no long term environmental harm. As recycling goes. New techniques to reuse plastics or recycle them are coming. One unique aspect is home construction.

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In 3rd world, plastic waste is rarely recycled... housing scarce and building materials expensive. Plastic is ubiquitous... a house derived using plastic feedstock. They are

  • rot resistant
  • bug resistant
  • moderately fire resistant, as they contain no instantaneous combustible materials.
  • mold resistant, invulnerable to humidity and easy to clean.
  • hypoallergenic
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    >Plastic wastes are largely inert. Stored in landfill pose no long term environmental harm But plastic from landfills may end up in the surrounding area or in the ocean; animals will eat it and choke. Also I'm not sure if microplastic is considered inert, looks like there is no consensus on that so far
    – Amomum
    Nov 29, 2022 at 12:48
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Going back to the original question but paraphrasing ... what are the factors against storing plastic waste?

The main thing against storing it underground is the "out of sight out of mind" tendency we humans suffer from. It's easy to forget it's there. Just set up an industry to bale it and drop it down a hole. Not solving the incrementing problem of too much unused plastic above ground.

The best way 'to get rid of plastic waste' is to call it another name. Proponents of the Circular Economy are calling plastic waste a resource that needs to be transformed and put back into the loop, to be sold again.

As a resource, it won't be wasteful and/or labor intensive to sort it (Sorting that at first may be done by humans, later by robots) and truck it to different factories to be transformed. All processing will be paid for by the eventual product.

EG So far, 16% of Car-tyres thrown out every year in Australia are being reprocessed and made into soft fall surfaces, artificial turf and conveyer belts; road construction and surfacing; alternative fuel source for producers of energy and cement; brake pads and other rubber products. Sourced from Planet Ark

As a still largely unused resource sitting around in plain view, more people will want value from it, and pay for research & development. Tonerplas asphalt was developed using recycled soft plastics, glass and toner cartridges.

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  • So, nothing immediately wrong with just storing it now and use it as a resource later? Sure, this "out of sight out of mind" tendency is what brought us in the current mess of things and I agree that this is a big red flag here.. but still, any kind of recycling - afaik - is still too expensive compared to the using oil. Maybe when oil prices skyrocket, using plastic again will be profitable but until then any kind of waste management needs to be paid for by the state (i.e. by tax-payers).. and state also wants to pay as little as possible :\
    – Amomum
    Dec 5, 2022 at 23:41
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The best way to store plastic after its useful life, at this moment of time, is still storage underground. Although the world in 2019 produced 460 million tonnes of plastic, many types are now hard to live without. For example,having so many people to feed would be almost impossible without plastic packaging for food keeping and distribution. Many medical interventions eg vaccinations throughout the world, operations, prosthetic limbs, intravenous delivery of meds would be almost impossible without plastic.

There are now 9.5 billion tonnes of plastic in existence, according to ourworldindata.org Burning plastic to produce plastic char is not an option, though already happening, as the poisonous gases released add to atmospheric pollution.

So far, about 20% of post-use plastic is being collected, stored (Australia is still using landfill) and recycled, mainly by developed countries with usually, as mentioned above, governmental input.

One of the articles I read states that the best way to control 'plastic mismanagement' is for developed countries to help the rest of the world develop strategies for decreasing one-use plastics, and for storage of plastic waste.

I'm hopeful that science will come up with good recycling solutions. Storing plastic underground, possibly already sorted, will represent a great storehouse of material when a plastic-based industry takes off.

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    I somewhat disagree that plastic burning would necessarily lead to poisonous gases. Well-engineered waste-to-power plants burn it cleanly, or at least as cleanly as they would burn wood, coal or oil.
    – juhist
    Dec 1, 2022 at 15:33
  • I agree with that @juhist, waste-to-power plants that are well-engineered prevent gaseous and solid (from ash) wastes poisoning the atmosphere. But many countries are still allowing landfills to incinerate wastes without any filtering of either gases or ash. Australia where I live has two WTE plants still being built, with 530 municipal councils, most doing landfill and flaring off unfiltered methane. And we're meant to be developed.
    – MocBird
    Dec 2, 2022 at 3:14
  • @juhist cleanliness of burning is just one aspect. Burning plastic (especially clean burning) requires additional energy input in the form of flammable oil derivatives. And burning will release CO2. Sure, that's better then simply burning the landfils..
    – Amomum
    Dec 2, 2022 at 12:23
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    Yes, it's true that clean burning requires for example natural gas (i.e. methane) to help the burning process. However, if you capture the carbon dioxide output of the waste-to-energy plant, and combine the carbon dioxide with hydrogen created by electrolysis, you actually get more methane out than you put in there in the first place. This isn't currently done on a massive scale, but I suspect it won't take many years until that is the source of our methane.
    – juhist
    Dec 3, 2022 at 10:14
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What you're missing is that an insignificant amount of the oil we use is used to create plastic.

Thus, it won't matter even a tiny bit if all plastic we use is stored underground. It's a good idea, though, but it won't scale because we use so little plastic. This is just like proposing using biofuels for all cars -- we just can't make enough biofuels for that.

Plastic use is only 380 million tonnes per year.

For comparison, Finnish forests (that grow very slowly), grow at a rate of 100 million cubic meters per year. One cubic meter is 420 kg, so that's 42 million tonnes per year. And that's only Finland, one very small country, that has only 23 million hectares of forest. If we assume every forest on this planet grows at the same rate (probably most grow way faster because most countries are warmer than Finland), the 4.06 billion hectares of forest in the world should grow at a rate of 7400 million tonnes per year. Probably world forest growth is maybe 2 times that since so many forests are in warm countries.

So forests grow at least at a rate 20 times greater than plastic usage. You shouldn't be looking at storing plastic underground, but you should instead be looking at storing forestry products underground.

What we should do, is to:

  • Chemically recycle all plastic (not into liquid fuels but into new plastic) in a manner that makes it as good as newly produced plastic. There are methods to do that. Current mechanical recycling makes inferior quality plastic that is a very poor product. But chemical recycling will change all that.
  • Use chopped down trees to create all new plastic.
  • Stop all oil usage, as fuel, as raw material for new plastic.
  • Maybe use some amount of forestry waste for making biochar and use that for carbon storage. Currently forestry waste is used as a fuel for creating heat, but that's just ridiculous. Heat should be created by renewable energy and heat pumps, freeing that large stream of forestry waste, allowing using it for making biochar.

So it's true that carbon-containing materials should be buried underground, but that material probably isn't plastic (we just have too little plastic), but biochar created from wood. Biochar is way better because we can make so much of it. Well, we could make very much plastic too but there wouldn't be any point in it.

Also biochar doesn't create any "micro-biochar" contamination concerns like plastic creates microplastic concerns.

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  • > What you're missing is that an insignificant amount of the oil we use is used to create plastic. You probably talking from the point of carbon emission but plastic waste creates problems by itself, it's in the oceans and forests, microplastic inside our blood etc. Burying plastic is - in my view - is just a way of preventing that direct plastic contamination without increasing CO2 production, not reducing overall CO2 emissions.
    – Amomum
    Nov 26, 2022 at 22:15
  • Well yes, but then you have to be really sure the storage method for storing plastic doesn't leave it to the environment with wind. Most actively used landfills leak plastics to the environment with wind. Maybe it's better to simply burn or chemically recycle the plastic, and use biochar made from trees for CO2 sequestration?
    – juhist
    Nov 27, 2022 at 10:14
  • I dunno, maybe it is :) That's why I'm asking. For me it seems strange to release CO2 and then capture it again, that - surely - should take more energy than not releasing it at all?
    – Amomum
    Nov 27, 2022 at 15:59

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