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Yes, I've come to the conclusion that it's better to bury most plastic waste. Most plastic comes from oil, which means 'biodegradable' plastic is essentially t

Yes, I've come to the conclusion that it's better to bury most plastic waste. Most plastic comes from oil, which means 'biodegradable' plastic is essentially the same as burning the oil. Actual recycling can work in some cases, but even after all the expense and energy of recycling, the recycled product is usually much lower grade plastic, so it's not sustainable. Better just to bury it (in leak-proof pits), where it will turn back into oil eventually. The real problem with plastic waste is COLLECTING it, making sure it doesn't wash into the oceans, etc. At least the recycle logo might help with that, even a fake one.

irrational 5y ago
Wait, does plastic really turn back into oil over time? How much time are we talking about here?
- deleted 5y ago
  [deleted]
- neltnerb 5y ago
  Not our lifetime. I disagree with the original poster. Often times manufacturing fresh polymer, while cheaper, uses many times the carbon content of the polymer in process energy. Just as an example I know about offhand, isoprene rubber takes five times the carbon content of the product to process from petrochemical feedstocks. That said, recycling isn't very good either, so better would be to just not use it unnecessarily in packaging. I do think it is better to incinerate than to recycle wrong and contaminate the entire recycling stream though. To me, ruining all the other recycling on top of lying about it being recyclable in the first place is way way worse. And no, you cannot generally recycle PLA... I'm not sure where that is coming from. I hate that PLA (often labeled as 7 even though that just means "other") confuses everything even worse when people try to just toss it into typical compost and thus ruin the compost too. Of course it would also ruin the recycling... it would literally be better to just throw it away to be incinerated or else use good old numbers 1 and 2.
  - Robotbeat 5y ago
    You can recycle PLA into recycled PLA filament for 3D printers. You can buy it online; it at one time was cheaper than new.
    - neltnerb 5y ago
      I don't doubt it, but not in standard curbside recycling bins basically anywhere.
- coryfklein 5y ago
  I'd really like to know the answer to this as well. From all the research I've done in the past 10 minutes, you'd think that plastic is simply immutable and indestructible, and that even after millenia has passed it will still be plastic (even if in smaller pieces). But the Google SEO on this is dominated by environmental groups trying to emphasize the short-term life cycle of plastics, and it's hard to find anything with a longer-term perspective. I think if you wait long enough (billions of years) then the landfills will eventually be under miles of earth and subjected to high enough pressures that they fundamentally change; in the same way sedimentary rock can change into metamorphic.
duckmysick 5y ago
> Better just to bury it (in leak-proof pits), where it will turn back into oil eventually. What's the time scale of turning back into oil? How long those pits are estimated to stay leak-proof?
- smileysteve 5y ago
  Given our best sealants are plastics, this is the best question.
  - Robotbeat 5y ago
    I would say vitrification is a better sealant. Or maybe welding shut in a thick stainless steel container.
JeremyNT 5y ago
In a world where fossil fuels are still a thing, how does burying it stack up against just burning it as fuel? I get that it's sequestered if it's in a landfill, but it seems like it might be more efficient to burn the carbon already extracted and turned into plastic than it would be to dig up new stuff and burn that (i.e. you get to leave more of the already-sequestered oil-carbon in the ground rather than digging it up and sequestering the plastic-carbon).
- deleted 5y ago
  [deleted]
- ZeroGravitas 5y ago
  The scientific consensus is that recycling > burning with energy recovery > well managed landfill > badly managed landfill > open burning. Nations not under the control of fossil fuel groups have been putting this into action for decades. Landfill seems to be the contrarian's choice but this appears to some anti-regulation propaganda after effect. Headlines like "Thing you do to save the planet actually hurts the planet" is like catnip for some people, and they dont ask any awkward questions about who is claiming this and why.
  - neltnerb 5y ago
    Landfill as an imagined route to sequestration is easily seen through with the right thought experiment. If you incinerate the trash instead of burying it, carbon does indeed get released. If you burned enough coal/naturalgas/oil to produce the same amount of energy produced by incinerating, you would release a comparable amount of carbon. Burying it doesn't sequester anything, if you assume it gets burnt to produce energy. If you burn it, you displace burning fossil fuels. I wish recycling was more realistic, it frustrates me to no end that out of all those cute numbers that indicate you should feel good putting it in the recycling bin, odds are that anything you put in made of 3, 4, 5 (sort of), 6, or 7 is counterproductive. It just contaminates the good stuff. But tangent aside, if you consider the plastics to be fuel it makes absolutely no sense to sequester them instead of burning them to displace fossil fuel use, reduce land use, and also centralize a major pollution source (plastics and such contaminating groundwater near landfills over centuries vs a centralized emissions filter).
hotshiitake 5y ago
> Yes, I've come to the conclusion that it's better to bury most plastic waste. Alright, here is a controversial hot take - we should probably just burn plastics - and most garbage actually - as fuel. Done properly, incineration is a simple way to limit environmental contamination caused by plastics and other waste materials. The extra GHG production would be partially offset by savings from simpler logistics for processing (no more shipping barges of waste plastic going to overseas dumps) , and significantly reduced methane emissions from landfills. And - depending on how cost-effective incineration is - we may be able to take savings from waste processing and double-down on removing emissions from other industries (e.g. Energy, transportation).
bratcomplex 5y ago
Gasification, using it as a fuel makes more sense. Reducing it down to basic carbon constituents. At least in this forum it’s productive and photosynthesis can turn it into organic mater.
- neltnerb 5y ago
  If you do incineration right (with pollution controls and energy recovery), simply burning it is more direct. Gasification is a nice intermediate step if you need to mix it with syngas or natural gas to augment supplies, but if you really just are going to convert to electricity or heat eventually you may as well just do it in one centralized step. Either way the plastic product is just one stop on the path from hydrocarbon to energy and CO2+H2O, but I do think centralized incineration is more practical (especially since it's already done all over the place) with little real downside. Just assume as a rough estimate that the gas you'd get from gasification is displacing natural gas production. If you just burn the plastic (and other trash) in a way that prevents serious pollution from getting into the air it's bound to be more efficient to do that and then just burn less natural gas -- versus trying to turn what is essentially already fuel into natural gas substitute.
Robotbeat 5y ago
Your second sentence is false. Almost all of the biodegradable/compostable plastics (those that are marketed as such) are biomass based. PLA comes ultimately from corn

irrational 5y ago

Wait, does plastic really turn back into oil over time? How much time are we talking about here?

deleted 5y ago
[deleted]
neltnerb 5y ago
Not our lifetime. I disagree with the original poster. Often times manufacturing fresh polymer, while cheaper, uses many times the carbon content of the polymer in process energy. Just as an example I know about offhand, isoprene rubber takes five times the carbon content of the product to process from petrochemical feedstocks. That said, recycling isn't very good either, so better would be to just not use it unnecessarily in packaging. I do think it is better to incinerate than to recycle wrong and contaminate the entire recycling stream though. To me, ruining all the other recycling on top of lying about it being recyclable in the first place is way way worse. And no, you cannot generally recycle PLA... I'm not sure where that is coming from. I hate that PLA (often labeled as 7 even though that just means "other") confuses everything even worse when people try to just toss it into typical compost and thus ruin the compost too. Of course it would also ruin the recycling... it would literally be better to just throw it away to be incinerated or else use good old numbers 1 and 2.
- Robotbeat 5y ago
  You can recycle PLA into recycled PLA filament for 3D printers. You can buy it online; it at one time was cheaper than new.
  - neltnerb 5y ago
    I don't doubt it, but not in standard curbside recycling bins basically anywhere.
coryfklein 5y ago
I'd really like to know the answer to this as well. From all the research I've done in the past 10 minutes, you'd think that plastic is simply immutable and indestructible, and that even after millenia has passed it will still be plastic (even if in smaller pieces). But the Google SEO on this is dominated by environmental groups trying to emphasize the short-term life cycle of plastics, and it's hard to find anything with a longer-term perspective. I think if you wait long enough (billions of years) then the landfills will eventually be under miles of earth and subjected to high enough pressures that they fundamentally change; in the same way sedimentary rock can change into metamorphic.

duckmysick 5y ago

> Better just to bury it (in leak-proof pits), where it will turn back into oil eventually. What's the time scale of turning back into oil? How long those pits are estimated to stay leak-proof?

smileysteve 5y ago
Given our best sealants are plastics, this is the best question.
- Robotbeat 5y ago
  I would say vitrification is a better sealant. Or maybe welding shut in a thick stainless steel container.

JeremyNT 5y ago

In a world where fossil fuels are still a thing, how does burying it stack up against just burning it as fuel? I get that it's sequestered if it's in a landfill, but it seems like it might be more efficient to burn the carbon already extracted and turned into plastic than it would be to dig up new stuff and burn that (i.e. you get to leave more of the already-sequestered oil-carbon in the ground rather than digging it up and sequestering the plastic-carbon).

deleted 5y ago
[deleted]
ZeroGravitas 5y ago
The scientific consensus is that recycling > burning with energy recovery > well managed landfill > badly managed landfill > open burning. Nations not under the control of fossil fuel groups have been putting this into action for decades. Landfill seems to be the contrarian's choice but this appears to some anti-regulation propaganda after effect. Headlines like "Thing you do to save the planet actually hurts the planet" is like catnip for some people, and they dont ask any awkward questions about who is claiming this and why.
- neltnerb 5y ago
  Landfill as an imagined route to sequestration is easily seen through with the right thought experiment. If you incinerate the trash instead of burying it, carbon does indeed get released. If you burned enough coal/naturalgas/oil to produce the same amount of energy produced by incinerating, you would release a comparable amount of carbon. Burying it doesn't sequester anything, if you assume it gets burnt to produce energy. If you burn it, you displace burning fossil fuels. I wish recycling was more realistic, it frustrates me to no end that out of all those cute numbers that indicate you should feel good putting it in the recycling bin, odds are that anything you put in made of 3, 4, 5 (sort of), 6, or 7 is counterproductive. It just contaminates the good stuff. But tangent aside, if you consider the plastics to be fuel it makes absolutely no sense to sequester them instead of burning them to displace fossil fuel use, reduce land use, and also centralize a major pollution source (plastics and such contaminating groundwater near landfills over centuries vs a centralized emissions filter).

hotshiitake 5y ago

> Yes, I've come to the conclusion that it's better to bury most plastic waste. Alright, here is a controversial hot take - we should probably just burn plastics - and most garbage actually - as fuel. Done properly, incineration is a simple way to limit environmental contamination caused by plastics and other waste materials. The extra GHG production would be partially offset by savings from simpler logistics for processing (no more shipping barges of waste plastic going to overseas dumps) , and significantly reduced methane emissions from landfills. And - depending on how cost-effective incineration is - we may be able to take savings from waste processing and double-down on removing emissions from other industries (e.g. Energy, transportation).

bratcomplex 5y ago

Gasification, using it as a fuel makes more sense. Reducing it down to basic carbon constituents. At least in this forum it’s productive and photosynthesis can turn it into organic mater.

neltnerb 5y ago
If you do incineration right (with pollution controls and energy recovery), simply burning it is more direct. Gasification is a nice intermediate step if you need to mix it with syngas or natural gas to augment supplies, but if you really just are going to convert to electricity or heat eventually you may as well just do it in one centralized step. Either way the plastic product is just one stop on the path from hydrocarbon to energy and CO2+H2O, but I do think centralized incineration is more practical (especially since it's already done all over the place) with little real downside. Just assume as a rough estimate that the gas you'd get from gasification is displacing natural gas production. If you just burn the plastic (and other trash) in a way that prevents serious pollution from getting into the air it's bound to be more efficient to do that and then just burn less natural gas -- versus trying to turn what is essentially already fuel into natural gas substitute.

Robotbeat 5y ago

Your second sentence is false. Almost all of the biodegradable/compostable plastics (those that are marketed as such) are biomass based. PLA comes ultimately from corn