Even smarter would be to take that plastic and burn it for energy, instead of giving that energy to an enzyme, that will just make waste heat.
After reading the article instead of the headline:
They imply they can turn the plastic back into a monomer and then rebuild it as a new polymer. Maybe that would work, but I have huge doubts - a monomer is very chemically active, and it really wants to polymerize. That enzyme may work in a lab, but I doubt they can turn it into an industrial process.
I take issue with this:
"The most common method for disposing of plastic, besides throwing it in a landfill, is to burn it, which is costly, energy intensive and spews noxious gas into the air."
This is utterly false, and I don't see how they can claim to be scientific if they publish falsehoods. It makes me wonder about the accuracy of the rest of the press release.
They're dirtier than natural gas power plants, however. (and the pollution that they do create can be particularly nasty) We're better off in terms of emissions-per-watt by burying the plastic and using natural gas instead.
> They're dirtier than natural gas power plants, however
That is not true.
> and the pollution that they do create can be particularly nasty
That is also not true.
Plastic is made of the exact same atoms as natural gas, plus oxygen. Plastic burns very very clean, with no waste except for water and CO2.
PVC has chlorine, but is rare in trash, and the small amount of chlorine is easily filtered out of the exhaust.
> We're better off in terms of emissions-per-watt by burying the plastic and using natural gas instead.
This is also not true because it costs energy to extract the natural gas. The plastic is already there, and needs to be dealt with one way or another. Plastic makes about the same CO2/watt as gasoline.
Plastic that goes into the trash is not pure plastic, it is trash and it has a lot of other junk in it. i.e. heavy metals and other stuff. That's one of the biggest reasons we have trouble recycling it. Are there even any WTE plants that burn only plastic?
It's very easy to separate metals from plastic. The paper mixed in can just stay, as can most other waste. That's one of the nice things about burning it - almost all trash will burn, except for metal and glass. Metal is easily removed before, and glass can be removed from the ash.
> Are there even any WTE plants that burn only plastic?
Tons of them. There are more of those than classic recycling. They just stay under the radar so people don't get upset (since like many people in this thread, they think it's dirty when it is not).
Yes. I see quite a few three letter accounts advocating for burning plastic. Let them throw some in their fireplace of the chimnea while relaxing with the family and see how that goes.
I recall throwing some plastic bottlecaps in fireplaces during my youth. IIRC, they'd get melty, then the puddle would ignite and burn very hot, until it was spent, and that would be about it. Might have smelled funny, but I can't remember that far back; was less sooty than the wood at least. Of course, water bottle caps aren't likely to have food waste or much of anything else other than the plastic, maybe a smidge of water and some fingeroils from handling. I also didn't have a gas spectrometer or anything, and the fireplace wasn't an industrial furnace with process controls and what not.
On the topic of food waste, my time in the kitchen says most foods will burn just fine. Although, they often leave residues that I could see being problematic when they build up.
As with everything, you'd need specifics to determine the right tradeoffs. It would seem to me there's potential in reducing the transport distance and land use of solid waste, and also reducing extraction, transport, and burning of some fossil fuels, if a burn the trash for electricity program works. But specifics matter, of course.
I wouldn't exactly call it noxious, but C02 isn't exactly something we want to be spewing more of. Isn't a landfill full of plastic pretty much just a big pile of captured carbon?
It's captured oil basically, not captured CO2. (Don't say "captured carbon", when you mean "captured co2", because it leads to confusion - do you mean burned or unburned carbon?)
And since we are still pumping oil of the ground, leaving a different form of oil (plastic) in the ground doesn't accomplish anything useful.
I'm not sure what distinction you're trying to draw.
>And since we are still pumping oil of the ground, leaving a different form of oil (plastic) in the ground doesn't accomplish anything useful.
I suspect that overall energy production in the US probably emits less CO2 per kwhr than burning garbage does, so starting to burn garbage for energy would be, in that regard, a net negative. Furthermore, it would likely require moderately significant capital expenditure that could've instead been used for something better.
Why would you have NOx? The fire is not that hot. And no, there are no dioxines because they burn up in the fire.
> It's messy to the point that it's debatable if it's better just to bury it.
No, it's not. You do get that people are doing this already, right now? It's not some theoretical - there's a huge amount of plastics being burned, and it's very clean.
> that is wildly defamatory, with no evidence, right?
The evidence is right on their own website. Their advocacy that they are so proud of is actively harming the planet and they are sitting there proud of it.
What would be really cool is if we got something that could eat plastic and produce as a waste product some environmentally neutral substance like (say) some kind of alcohol. Is there anything like that on the horizon?
Please define environmentally neutral. Because alcohol will just oxidize into water and CO2.
Do you want to just sequester the Carbon? Something very environmentally neutral would be .... plastic. Anything biodegradable would eventually become CO2 and water.
Best option is to burn it and capture the energy for a useful purpose, instead of letting that energy be wasted when it biodegrades.
Or rather, how will governments and NGOs manage the problem (and by extension, the economy) if someone invents a technology that actually just solves it?
Plastic waste should be burned for heat and/or electricity in an incinerator. Every other usage/disposal method seems like a waste to me. Instead of burning fossil fuels directly, we get much more value from them if we first turn it into some plastic product, and only then burn it. And as long as we keep burning fossil fuels for heat and power, let's not wate out attention on recycling (downcycling actually) plastics as we can much better burn the old and make fresh new plastic from the fossil fuels we didn't have to burn because of that.
When we are not relying on fossil fuels anymore for heat and power (which is hopefully sooner than later), only then we need to start looking into plastic recycling
>At the plant, the garbage is first mixed with a large crane so that all the different kinds and sizes of items are uniformly distributed for easier burning. Next, the waste is incinerated at extremely high temperatures, over 800°C (1,472°F). This reduces not only the volume to 1/20 of what it was but also the amount of dioxin gases produced by incineration. Multiple provisions are made to prevent gases and harmful substances emitted during incineration, such as sulfur oxide and particulate matter, from being emitted outside the facilities. Chimneys of waste incineration plants emit vapor—not smoke—that does not contain harmful substances. Heat energy produced by the incinerator is used to supply the electricity needs of the entire facility, with any remainder being sold (earning approximately JPY 9.8 billion annually, or USD78.6 million, in income from electricity). High-temperature water is also supplied to neighborhood swimming pools and tropical plant greenhouses.
---
See also: Sweden also incinerates waste for heat and electricity, and a few years ago there was a story about how they ran out of trash and had to buy more trash from their neighbors.
My understanding is that incinerators don't just release the output. The exhaust is pumped back into the system and dealt with somehow. The extent to which the release is "dealt with" is the tricky part.
CO2 is bad but not toxic at all. It's inert. The toxic ones are toxic because they still have some energy left and the earlier you pull out that energy the better. Preferably in a plant that puts that energy to some form of use.
No, they produce water and CO2. Nothing toxic, unless you don't give enough air (so obviously make sure to give enough air).
This isn't some theory - right now, today, lost of plastic is being burned, and it works just fine. They try to keep is off the radar because of misinformed people thinking it's bad.
This is actually the "best" answer for our plastics problem. There was an NPR/Planet Money podcast on it recently here: https://www.npr.org/2020/09/11/912150085/waste-land and there are plenty of other sources that all agree on this premise. I have worked in waste management a few years ago and recycling is not the long-term solution.
> The utility of oil-based fuels is the energy density in combustion. Burning plastic doesn't come close to the same exchange.
The energy density of plastic (by weight, not volume) is virtually identical to that of oil.
Yes, the machine used to burn oil vs plastic looks different, but coal plants can burn plastic without much modification - and they would be much much cleaner than coal when they do so.
> The energy density of plastic (by weight, not volume) is virtually identical to that of oil.
Oil-based unleaded fuel is not oil. You probably could run trains on plastic. That's if you didn't mind hot plastic raining down around the tracks as the coal dust and soot did when we used it for trains.
We don’t burn oil though. We burn natural gas, in highly-efficient turbines. Burning oil and coal is obsolete technology that we are trying to phase out.
You do have significant differences between noxious fumes and clean burning between burning plastic vs burning fossil fuels. The energy captured from the burn is obviously not the same - same reason you can't just set fire to a "bowl" of plastic.
Even more to the point: we can avoid digging coal from the ground, which burns even dirtier than plastics trash.
And even in the lofty goal end state of zero fossils, if it's not a complete collapse back to medieval tech (and population numbers), we would likely end up with biomass based plastics serving as packaging and the like at the upper end of that carbon's energy slope, before utilizing the remaining bound energy in an incinerator.
Biodegradable properties of grown plastics are only a last line of defense against pollution when collection has failed.
Whether we should burn, recycle, or dump plastic into a landfill depends entirely on the relative amount of energy generated and CO2 emitted by those different options. Just because plastic and natural gas both are/come from hydrocarbons doesn’t mean that burning them produces anywhere near the same amount of emissions per MWh, or that the economics would be at all close.
And if you are proposing the construction of new power plants to burn trash, your justification also has to explain why that would be preferable to building wind/solar instead
>And if you are proposing the construction of new power plants to burn trash, your justification also has to explain why that would be preferable to building wind/solar instead
An easy to grasp reason is that we still can't viably store energy for long enough periods for wind and solar alone to work. Also solar and wind might not work so well everywhere.
That’s a favorite talking point of climate deniers, but even once storage becomes a concern this proposal is only one of many possible options. What I’m pointing out is that this thread doesn’t actually contain any quantitative argument why burning trash is competitive with, let alone superior to, credible alternatives
I think just about all household trash in the Netherlands is incinerated. And as far as I know the exhoust fumes are manageable, but definitely not something to live next to. Just like any other fossil fuel run powerplant by the way.
I understand that the pits, that are the foundation of landfills, are lined with impermeable plastic sheets. Their purpose is to avoid ground-water contamination. So, there may be some redesign of landfills required before this technology can succeed.
I was thinking the same. Worst case scenario with a solution like this one is that these organisms get into the wild, gain more mutations, and then rapidly release a large volume of carbon, currently sequestered as plastic, into the atmosphere. Or, plastic-tropic organisms used as a weapon, sprayed over cities, etc.
Note: the article talks about an enzyme, which is a simple protein. They might manufacture it via organic means, but the enzyme by itself has no capacity to reproduce or mutate.
That is true, but the best and easiest way to make a huge mass of a specific enzyme is to grow it in something, either bacteria or yeast. If it is in an organism, the organism can escape into the wild.
That's a much smaller threat than if the organism itself were to be applied directly to plastics.
Designer organisms aren't generally well-suited to spreading in the wild and even if they were, they could be engineered to require a certain dependency that they would die without. But yes, still theoretically it's possible.
There are many different types of plastic and they have surprisingly different molecular structures. Enzymes are remarkably specific catalysts, so an enzyme that eats PET [1] can’t eat another type of plastic, like HDPE [2]. So one solution could be to engineer an enzyme that can’t eat the liner material.
I’m not sure if HDPE would make a good liner material or not, but just as an example, the differences in molecular structure between PET and other plastics are big enough that it would take an array of different enzymes to eat them all.
I wonder what the potential harm to infrastructure would be if this bacteria were to escape landfills / remediation sites and happen to get into places where PET is used in something important.
Not that I'm against finding ways to _actually_ recycle or break-down plastics, just it seems like something we need a microscope to see might be hard to keep track of.
That's the real question. It doesn't "eliminate" anything. It turns it into - what? Organic sludge? Is that useful for something?
Plastic bottle recycling into new plastic pellets works quite well. Southern California has a huge plant doing it. Non-bottle plastic is more of a problem but less of the volume.
Can't help but wonder if this is a solution searching for a problem. Landfills already have protections against leeching into the surrounding environment. And we aren't going to plausibly run out of space for landfills in the foreseeable future (images from Wall-E notwithstanding). Isn't plastic basically inert once it gets to a landfill anyway? Even if it takes centuries to break down, who cares?
IMO we'd be better off focusing research on reducing the waste rather than improving disposal.
Correct me if I'm wrong, but doesn't this process still assume that the plastic is collected and heated (not super hot, the claim seems to be "less than 50C")? In the case of the ocean, it doesn't seem like this technology would be useful until after we collect all the little bits of plastic. And at that point we could just put it in a landfill anyway.
Yeah, good point. Theoretically, a more optimized enzyme might be able to do it at ambient temperatures, which they mention in the article as a target. Assuming the search space for enzyme mutations isn't already exhausted.
> a more optimized enzyme might be able to do it at ambient temperatures
Releasing this into the ocean, in any appreciable amount, seems like a very bad idea. I think collection from plastic "hot spots", and then separate processing, would make more sense. I think it's best to reduce the number of foreign chemicals in the environment.
> IMO we'd be better off focusing research on reducing the waste rather than improving disposal.
And IMO there’s much upside to pursue multiple avenues to desired solutions, rather than making choices to eliminate potentially contending solutions too early.
Mother nature herself provides pretty much exactly that template for evolution. So if we want to save nature, why not use that same approach? It seems to have served the survival of life on our planet rather well.
We should be focusing on reducing trash and getting raw materials back out of trash. The rest should be burned or processed cleanly and maybe generate electricity while at it.
> Landfills already have protections against leeching into the surrounding environment.
Not to get into tinfoil hat territory, but can any large enough industry be trusted on narratives regarding how waste is handled ?
I don't think there is controversy around landfills leaking. There is debate on wether it's as bad as we think, or the actual impact, but then I find it hard to take a "We don't hear about it in the news, so it's probably fine" stance when we got served BS "we're all in on recycling, don't worry just buy more from us" narratives for decades with almost nothing actually getting recycled.
> As a result of advances in installation quality and CQA practices, leakage rates greater than 50 liters per hectare per day (lphd) have decreased significantly in the past 20 years.
Depends on what the waste products are and how they are captured, otherwise you trade one problem for another. The plastic takes up space but if it's in a landfill you have carbon capture, best not to release that carbon into the air as CH4 or CO2.
Depends what you mean by "major environmental problem". Landfills aren't going to singlehandedly cause anthropogenic climate change, but they contribute significantly to it, and a poorly sealed landfill leaching its contents into the local water table can cause some pretty drastic problems with the local environment
If you are worried about space i recommend that you look at the surface area of earth and the volume of space that’s accessible to us underneath the surface.
In the Western world maybe, but outside of it... hell even in the Western world we have regular reports of mismanagement and corruption, just look at Italy.
We need to reduce the amount of trash we produce, not hope for a miracle technology.
Landfills are not a miracle technology. They exist already and are technologically sound. It’d be way more of a miracle if we somehow managed to greatly reduce waste.
How sustainable are landfills? There's limited land for farming, residences, manufacturing, and everything else we use it for. And trucking trash to deserts to landfill there isn't carbon neutral either. Trash also doesn't breakdown as quickly in covered landfills (for better or worse depending on what one dumps).
Given the yield of useful content vs. rock in mining, I suspect the more limiting factor is space for all the mining, not space for disposal of the 0.1% metal etc yield for making industrial goods.
People love to "what if" landfills. Best to not bother arguing with them. We have tons of problems with emissions, plastics pollution, industrial dumping. However landfills ain't one of them, but people won't give up. I've learned to not bother discussing anything with them if they don't know a few basics of how modern landfills are run (at least in western nations).
As others have mentioned they are a major source of methane emission, though this can be addressed (do a better job separating out food waste and compost it).
The thing about nimbyism in this case is that confortable commentators on hackernews are vanishingly unlikely ever to have to live near one. This is a poor people problem.
If it needs constant monitoring it's a potential problem... And at some point it will happen... We know that from ages of software development, if it can fail, it will fail at some point.
You’d be surprised by the number of things that need to be constantly monitored. Building structures, power plants, roads, dams, mass transit, etc. basically everything.
Dams break and wreck havoc on ecosystems, the US has had it's fair share of coal mine sludge disasters. Even countries with strict environmental agencies and long history of mining have accidents.
So what's your solution? Stop building dams and decommission the ones that have been built? Humans attempt to create order. The universe naturally wants to increase disorder. It's natural that anything we create will need to be monitored.
We know that dams are dangerous and that they fail, the smaller ones are decomissioned when not in use not only to improve the ecosystem. A dam is not designed for a life of a 100 thousands years, it's a long time.
I think the main problem is that the average Joe/Jane confuses all types of pollution as equally bad. The real, most imminent threat is really CO2. That's what we have to spend the most money/energy on, because it could have absolutely catastrophic consequences in the next few decades.
Plastic in a landfill is just... Stuck there. It's unnatural, sure, but it's not immensely harmful, not nearly on the same scale as CO2, and realistically, in the future, we'll be able to mine it out of there and refine it into something usable if we need it.
Garbage is also a problem in the environment like plastics in oceans, but the problem is not enough (well run and used) land fills (in Asia) not too many!
looks more like 10% [0]. but it depends on where in the ocean you're talking about - they float more easily than a lot of plastic, and so are caught the pacific gyre.
Nuclear fuel must first be mined, correct? That's not renewable and could offset the benefits somewhat. That said I imagine it may be better as a base load than dirty coal.
As far as I know that's pretty much exactly the amount of fissile material used annually world-wide.
The caveat is of course that for 1 kg of coal you have to dig up a lot less material than you have to for 1 kg of fissile material - U235 is around 1 % of natural Uranium, and Uranium is around 1 % of the ore.
> Also, the very premise that more CO2 is existential is contradicted by historical record: 250 million years ago earth was 15 degrees warmer than it is now and CO2 was a lot more abundant.
Maybe this is just a joke that sailed over my head, but this is obviously false and doesn't mean anything of the sort. Existential for whom? All you can definitely conclude is that the Earth won't explode if the climate increases by 15 degrees. You can guess that life would survive, but there were no humans back (or large mammals at all) back then. There's no reason to think we would make it.
> The people controlling the media won’t allow it. This is common knowledge.
This is just rank conspiracism. I know of no evidence to suggest that the media are somehow controlling events (?), laws (?), the "narrative" (?), simply to prevent nuclear reactors from being built. How? For what purpose?
And claiming "this is common knowledge"? Maybe that was just another joke, because normally when one says a conspiracy theory is true, one also claims that this is secret information that has to be carefully mined out of various data sources, because if everyone knows something is happening it's usually not a very good conspiracy.
We see animals and people living with 15 degrees spread now. That won't change.. people and animals would exist at 25 degrees. Not as many and not in all places.. but we can be sure humans will survive somewhere aided by technology.
> simply to prevent nuclear reactors from being built. How? For what purpose?
If a country has sufficient nuclear energy then they are immune from international energy politics.
Two, I see that the oligarch class is using global warming alarmism as the driving narrative to move everyone to a carbon credit system, where payouts go to an unaccountable transnational elite.
Ironically, I believe that once the incentive structure is in place, there will be institutional force to keep you buying carbon (offsets) credits… forever.
This is a striking example of what I've observed in many places which has often made me wonder why the intersection between nuclear advocacy and some form of climate change denialism is so large? The inconsistency is odd: "I passionately believe we should be using nuclear power to solve a problem I don't actually believe is a problem".
Eh it's probably just a version of "owning the libs". By and large the leftist environmentalists and "tree huggers" are anti-nuclear, so you basically annoy them in two different ways.
People believe if you truly care about reducing CO2 not using nuclear means you will not be able to move off of fossil fuels until we are well past too late.
It's the flaw that makes reducing global warming a talking point vs an actionable item. It's a big elephant in the room.
Until that gets resolved many will think some are spinning your wheels.
The real threat is the nearly 1 trillion tons of toxic waste we're racking up PER YEAR. It's the most lethal stuff this planet has ever encountered.
If the CO2 levels spike, life on the planet (including many or maybe even most humans) will survive. If you look at historic levels, they were hundreds of times higher and the planet was the greenest it has ever been.
If/when that toxic waste leaks out and starts killing, NOTHING will survive.
And the thing is that these are actually harming the people who are near the area where they are disposed, so the harm is more direct.
CO2 is more like a global problem, so not as worrisome for the local population.
> The area around Chernobyl is very green and many animals live there. Things survive..
Only if you're talking about Putin's Little Green Men, in which case most were last seen heading to their deathbed in Belarus after having exposed themselves to deadly levels radiation after occupying the area and trenching it, to the total dismay of local Ukrainians and Plant workers!
Life does indeed find a way, but not in the way most think.
> In a way radioactivity is one of the easiest contaminants to deal...
What an absurd statement, if that were the case you'd go live and work in Fukushima and take advantage of all the open area and low cost real estate, and all the plentiful food that comes from that region.
Radiation to this day still hasn't been cleaned up in Chernobyl, which happened almost 40 years ago, and an Evacuation Zone is still in place.
And by the way their is an ongoing fire in the area as we speak that is cause for concern [0].
In a way radioactivity is one of the easiest contaminants to deal with: Instant, contact-free testing for levels is trivial with cheap, handheld devices, compared to virtually all other toxic substances which usually require taking samples and analyzing them in a lab. Decay is very well understood and easy to characterize.
Sperm counts have been dropping for a long time (50%-60% over the past 50 years) without stopping, and plasticizers are the suspected culprit. It's incredible how many people need to do IVF now. I would argue that might be the most imminent threat but nobody seems to care.
Speaking as someone that had to go through IVF, that's a bit like celebrating cancer for reducing the population. Infertility is devastating for you and your relationship when you want to have children.
Infertility would be "none", and I didn't say that, I said "fewer".
But I'm sorry you've put such an important emphasis on having kids in your relationship. The fact that you live in a society where that's reasonable is immensely sad, to me.
You should feel whole without children, and the fact that you don't is the real tragedy, IMO.
Large majority of developed countries are below replacement rates, so there's no need to gloat in the suffering and pain of people who can't have children.
Every couple of years this concern bubbles up. It seems to be established that sperm counts in males are going down. But I’ve yet to see substantial evidence about the possible causes. The effect of plasticisers e.g. were found in animal models usually with rather high doses. An increase of obesity over the last 50 years might also be a likely cause as obesity is linked with hormonal issues. Furthermore, the average age of first time parents has increased significantly. That could also explain why IVF got more popular as sperm counts (and egg „quality“) are age dependent as well.
AFAIK there is no empirical study today proving any link between environmental issues and sperm counts.
I'm certainly no expert, but from what I've seen the scientists are pretty firm in their belief it has nothing to do with obesity or other societal factors. Most of those are fairly easy to control for.
> Per the most recent Inventory Report, U.S. landfills released an estimated 109.3 million metric tons of carbon dioxide equivalent (MMTCO2e) of methane into the atmosphere in 2020; this represents 16.8 percent of the total U.S. anthropogenic methane emissions across all sectors.
Yes, for that reason Santa Clara County (Silicon Valley) is pushing hard to divert food waste out of the garbage and get it composted instead: it's supposed to go in with yard waste, not the regular trash. Not sure how successful this is as it counts on people putting things in the correct bin.
Here in the UK you can actually be fined for putting food waste in the regular bin (although that depends on where you live and enforcement is spotty).
There is a program like that in some suburbs of Sydney. We get little green bags for compostable waste. The up take has been ok from what I’ve seen but these are affluent suburbs.
As a county resident, I also started doing this recently, and I am amazed how much organic waste we were throwing away previously. My regular trash can takes much longer to fill, and I am constantly taking out the little kitchen bin (that was provided by the waste company).
Diverting compostables out of the regular trash stream also makes the regular trash stream not stink. My under counter trash bin can go two weeks easy without stinking up the place. It is mostly plastic that can't be recycled.
Composting is good, but it's heavy and hence energy inefficient if it's transported too far. This goes for almost all waste but the amount of water in compost and the transport distance adds upp. Handling waste and composting as local as possible is important.
Those microplastics aren't coming from landfills. They're coming from your everyday interactions with plastic and people dumping plastic in rivers and oceans.
Maybe not the landfills once they are buried. But certainly from waste transfer stations or unburied waste, seagulls and other birds will pick up trash because it smells like food or may have some food in it, and then drop it outside of the landfill/transfer station.
Well, it's easy to say if you don't live near one.
But if you do, the smell, view, and fact that ground water becomes undrinkable will convern you. Not to mention the space they take, where little life can live on.
In the USA, you have a huge space, including deserts, so a landfill may be out of most human reach. But in France, landfills can't be far, and take the place of either a forest, or accomodations.
We don't have a better way to deal with the huge amount of trash than landfills for now. But reducing the number or size of them would be a nice to have.
I don't mean it should be a priority compared to most urging issues like climate change, but let's not get too comfy with it either.
The US sends millions of tons of trash to China, India, and other places. Perhaps it would be better for places to implement local sorting (glass, plastic, paper, etc.) and composting- as many other nations do as opposed to disposing of all trash in the same containers and shipping the problem off for someone else to deal with. But even better would be to generate less trash in the first place or at least have an attempt at transitioning to using biodegradable packaging. Packaging, which also is excessive and unecessary in the first place, like items in layers of plastic casing, plastic boxes, plastic wrapping, and so on when there are ways of distributing goods without convenient prepackaging in favor of instead refilling reusable containers or utilizing materials such as fabric, glass, or others which can be repurposed and reused more flexibly and reliably than plastic.
Not even going to get into plastics being contaminated by toxic things and leeching chemicals. Landfills are not harmless to ecosystems and aquifers, either- they're a short term way of not dealing with the issue of waste materials, at best.
The article talks about using it for environmental cleanup, but the paper seems more focused on recycling back into fresh PET[0]:
> ...and a circular carbon economy for PET is theoretically attainable through rapid enzymatic depolymerization followed by repolymerization or conversion/valorization into other products
> Finally, we demonstrate a closed-loop PET recycling process by using FAST-PETase and resynthesizing PET from the recovered monomers. Collectively, our results demonstrate a viable route for enzymatic plastic recycling at the industrial scale.
I used to think burying plastic in landfills for carbon sequestration was a good idea. Then I found out that making plastic releases an enormous amount of CO2.
Thus, successful recycling of plastic would mean less new plastic being made, and less emission. Before renewables, petroleum not made into plastic would instead be burned as fuel. But now, or soon, maybe it will be left in the ground, instead, as not worth pumping out. It is better to leave carbon sequestered where it is than to extract and then sequester it.
It's a good thing we're all rich here, able to move to places with better climates or buy air conditioners, not the billions of poor people who have no way to survive intensifying extreme weather events.
Plastic production worldwide is 300 million tons. I am not sure how this would convert to tons of CO2 as it burns (each carbon in the polymer chain associates with more oxygen in the air so it becomes heavier) but the world's CO2 emissions are 30 billion tons, so this would be in the order of 1 to 3% of the whole world's emissions.
Not saying it's good, but burning plastic if it has environmental and health benefits is not out of question. Probably most of it is burned already (it definitely is in Asian countries).
> Probably most of it is burned already (it definitely is in Asian countries)
Germany seems to have invented the term "thermal recycling", i.e. burning plastics. IIRC, it is actually considered a renewable energy source by the law.
It's not the worst idea per se, if done right, and waste separation is actually significant here because it simplifies calorific value control.
The press release points to the paper’s abstract. From that, it appears that it is specific to PET plastic. It can de-polymerase PET for later synthesis in new PET products. PET is already being recycled, the issue there is that recycled PET is not clean enough to reuse as food packaging. I hope this method does not suffer from this limitation.
having done some research on this topic, the problem is not what goes into the landfills.. the problems are in the plastics that do not make it into the landfills, the production of the plastics, and the over-dependence on single-use plastics since the era of the Bic-Pen
The phrase “single use” is doing some heavy lifting there, and I have no idea why that particular product is made to be patient zero for this.
A pen presumably gets hundreds or thousands of uses, depending on how you count. For example, one way product packaging is much more of a single use plastic.
That being said, I’d hate to lose plastics for bulk food packaging, unless there’s an equally food safe successor.
And then this escapes and starts to eat plastics in cars and other durable goods thus rendering increased near term maintenance costs across a large number of industries.... just a thought.
This is for an enzyme, not bacteria, but to answer your question bacteria still need water, so if you keep the plastic dry it should be fine even in such a world.
PET soda bottles will be sterilized, then sealed. The outside is dry and won't decompose. You won't be able to re-close it and leave it out though.
For things that need to stay wet, like drain pipes, you would add chlorine and use PVC which is unlikely to be edible to bacteria.
Wouldn't this be extremely dangerous if a form of "plastic rot" was created? Things like PVC sewer pipes, or any long-lived plastic parts in cars/equipment could now degrade over time, which could create huge costs to find alternative materials. After all plastic is pretty useful because it is biologically and chemically inert.
DeepMind's AlphaFold capabilities to model protein-folding is going to accelerate this kind of discovery at a quantum leap order of magnitude. The featured article notes a custom CNN was used here - but AlphaFold is a game changer in synthetic biology in general even though the first goals were human medical application focused.
BBC Science in Action [1] interviewed Prof John McGeehan of the Centre for Enzyme Innovation at Portsmouth University working on Bacteria breaking down Plastic in landfills. He explained his workflow of maybe selecting one candidate very carefully and occasionally out of many due to the cost/time involved & how DeepMind gave him more results in a single weekend (for free) than he had expected to see over his entire reasearch career.
Yes, I came across this recently and almost submitted, but it seemed like a minor development by the same team on news (discussed here) a couple of years ago, and searching around there was similarly titled stuff from mainstream news going back years.
Seems to be one of those things where, if you're not in the field, all the news is the same and sounds like a breakthrough, but it'll be 20y out from actual adoption for a while.
Agreed. I generally assume that any headline with the structure "X new thing could solve Y," where Y is a massive problem that everyone wants a silver bullet for, is clickbait. I've seen too many of them at this point.
Everyone wants a quick fix for climate change and pollution because it will absolve us of doing the hard work that the problem really requires. By all means, we should pursue such moonshot ideas - but like you said, it will be used to virtue signal some false idea of "progress" while the problem gets worse.
This is a bit of a cynical take, if a solution is 1% likely it seems natural that 99% of the time the solutions aren't viable. Implies the 1% is still possible.
Cynicism is warranted for the reason that the other commenter pointed out: the fossil fuel industry (and by extension, any Big Industry) will use moonshot ideas like this as ammo for their PR machine. "Don't worry about our lobbying against viable solutions right now - soon we'll have this new silver bullet idea." That sort of thing.
But it's definitely worth exploring those moonshot ideas, so I'm not shutting that idea down. It's just good to be aware of how these sorts of headlines are used in the service of greenwashing.
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[ 3.8 ms ] story [ 285 ms ] threadAfter reading the article instead of the headline:
They imply they can turn the plastic back into a monomer and then rebuild it as a new polymer. Maybe that would work, but I have huge doubts - a monomer is very chemically active, and it really wants to polymerize. That enzyme may work in a lab, but I doubt they can turn it into an industrial process.
I take issue with this:
"The most common method for disposing of plastic, besides throwing it in a landfill, is to burn it, which is costly, energy intensive and spews noxious gas into the air."
This is utterly false, and I don't see how they can claim to be scientific if they publish falsehoods. It makes me wonder about the accuracy of the rest of the press release.
That is not true.
> and the pollution that they do create can be particularly nasty
That is also not true.
Plastic is made of the exact same atoms as natural gas, plus oxygen. Plastic burns very very clean, with no waste except for water and CO2.
PVC has chlorine, but is rare in trash, and the small amount of chlorine is easily filtered out of the exhaust.
> We're better off in terms of emissions-per-watt by burying the plastic and using natural gas instead.
This is also not true because it costs energy to extract the natural gas. The plastic is already there, and needs to be dealt with one way or another. Plastic makes about the same CO2/watt as gasoline.
> Are there even any WTE plants that burn only plastic?
Tons of them. There are more of those than classic recycling. They just stay under the radar so people don't get upset (since like many people in this thread, they think it's dirty when it is not).
A fireplace is a smoky thing, without enough air (even the wood makes a lot of smoke). An incinerator makes sure to supply enough air.
On the topic of food waste, my time in the kitchen says most foods will burn just fine. Although, they often leave residues that I could see being problematic when they build up.
As with everything, you'd need specifics to determine the right tradeoffs. It would seem to me there's potential in reducing the transport distance and land use of solid waste, and also reducing extraction, transport, and burning of some fossil fuels, if a burn the trash for electricity program works. But specifics matter, of course.
> which is costly
Burning is not costly it is cheaper than all other methods. It's so cheap it's actually profitable.
> energy intensive
It actually provides extra energy, and reduces energy waste (because now we have to pump less oil.)
> and spews noxious gas into the air.
It spews nothing except water and CO2.
And since we are still pumping oil of the ground, leaving a different form of oil (plastic) in the ground doesn't accomplish anything useful.
I'm not sure what distinction you're trying to draw.
>And since we are still pumping oil of the ground, leaving a different form of oil (plastic) in the ground doesn't accomplish anything useful.
I suspect that overall energy production in the US probably emits less CO2 per kwhr than burning garbage does, so starting to burn garbage for energy would be, in that regard, a net negative. Furthermore, it would likely require moderately significant capital expenditure that could've instead been used for something better.
It spews NOx and the whole bunch of undesirable things like dioxines.
You don't get pure PET and oxygen in, and you don't get pure CO2+H2O out.
It's messy to the point that it's debatable if it's better just to bury it.
> It's messy to the point that it's debatable if it's better just to bury it.
No, it's not. You do get that people are doing this already, right now? It's not some theoretical - there's a huge amount of plastics being burned, and it's very clean.
Why is it so common for people to pretend to be environmentalists and advocate for things that directly harm the environment?
who is "we" here ?
> to pretend to be environmentalists
that is wildly defamatory, with no evidence, right?
> that is wildly defamatory, with no evidence, right?
The evidence is right on their own website. Their advocacy that they are so proud of is actively harming the planet and they are sitting there proud of it.
Do you want to just sequester the Carbon? Something very environmentally neutral would be .... plastic. Anything biodegradable would eventually become CO2 and water.
Best option is to burn it and capture the energy for a useful purpose, instead of letting that energy be wasted when it biodegrades.
When we are not relying on fossil fuels anymore for heat and power (which is hopefully sooner than later), only then we need to start looking into plastic recycling
---
See also: Sweden also incinerates waste for heat and electricity, and a few years ago there was a story about how they ran out of trash and had to buy more trash from their neighbors.
This isn't some theory - right now, today, lost of plastic is being burned, and it works just fine. They try to keep is off the radar because of misinformed people thinking it's bad.
The hydrocarbons are going to get burned one way or another, you can just trade one type for another types.
You cannot replace most oil-based fuel with incinerators. So I'll disagree there.
The utility of oil-based fuels is the energy density in combustion. Burning plastic doesn't come close to the same exchange.
The energy density of plastic (by weight, not volume) is virtually identical to that of oil.
Yes, the machine used to burn oil vs plastic looks different, but coal plants can burn plastic without much modification - and they would be much much cleaner than coal when they do so.
Oil-based unleaded fuel is not oil. You probably could run trains on plastic. That's if you didn't mind hot plastic raining down around the tracks as the coal dust and soot did when we used it for trains.
They burn MUCH MUCH cleaner that coal for example.
> The energy captured from the burn is obviously not the same
There is nothing obvious about it. I don't understand what you mean? Plastics have around the same energy density as oil.
And even in the lofty goal end state of zero fossils, if it's not a complete collapse back to medieval tech (and population numbers), we would likely end up with biomass based plastics serving as packaging and the like at the upper end of that carbon's energy slope, before utilizing the remaining bound energy in an incinerator.
Biodegradable properties of grown plastics are only a last line of defense against pollution when collection has failed.
And if you are proposing the construction of new power plants to burn trash, your justification also has to explain why that would be preferable to building wind/solar instead
An easy to grasp reason is that we still can't viably store energy for long enough periods for wind and solar alone to work. Also solar and wind might not work so well everywhere.
https://www.goodreads.com/book/show/86452.Ill_Wind
Designer organisms aren't generally well-suited to spreading in the wild and even if they were, they could be engineered to require a certain dependency that they would die without. But yes, still theoretically it's possible.
An enzyme is a protein not an organism
> a flexible membrane (i.e., geo-membrane) overlaying two feet of compacted clay soil lining the bottom and sides of the landfill.
https://www.epa.gov/landfills/municipal-solid-waste-landfill...
I’m not sure if HDPE would make a good liner material or not, but just as an example, the differences in molecular structure between PET and other plastics are big enough that it would take an array of different enzymes to eat them all.
1. https://en.m.wikipedia.org/wiki/Polyethylene_terephthalate 2. https://en.m.wikipedia.org/wiki/Polyethylene
Not that I'm against finding ways to _actually_ recycle or break-down plastics, just it seems like something we need a microscope to see might be hard to keep track of.
At the very least, I'm sure it won't be as bad as in BioMeat: Nectar.
Plastic bottle recycling into new plastic pellets works quite well. Southern California has a huge plant doing it. Non-bottle plastic is more of a problem but less of the volume.
There is such thing called second law of thermodynamics.
The only question is into how much stages we can split this process, and how much useful stuff we can extract from each of those.
IMO we'd be better off focusing research on reducing the waste rather than improving disposal.
Releasing this into the ocean, in any appreciable amount, seems like a very bad idea. I think collection from plastic "hot spots", and then separate processing, would make more sense. I think it's best to reduce the number of foreign chemicals in the environment.
And IMO there’s much upside to pursue multiple avenues to desired solutions, rather than making choices to eliminate potentially contending solutions too early.
Mother nature herself provides pretty much exactly that template for evolution. So if we want to save nature, why not use that same approach? It seems to have served the survival of life on our planet rather well.
Not to get into tinfoil hat territory, but can any large enough industry be trusted on narratives regarding how waste is handled ?
I don't think there is controversy around landfills leaking. There is debate on wether it's as bad as we think, or the actual impact, but then I find it hard to take a "We don't hear about it in the news, so it's probably fine" stance when we got served BS "we're all in on recycling, don't worry just buy more from us" narratives for decades with almost nothing actually getting recycled.
PS: more on leakage from an industry publication: https://wasteadvantagemag.com/how-much-does-my-landfill-leak...
> As a result of advances in installation quality and CQA practices, leakage rates greater than 50 liters per hectare per day (lphd) have decreased significantly in the past 20 years.
And, as you say, they're pretty good carbon deposits, which is supposed to be The Most Important Thing.
... yet?
All material that can end up in landfills is already on Earth.
Is it that it comes out as methane from landfills but less harmful CO2 from a little pile? That should be solved by flaring the methane.
We need to reduce the amount of trash we produce, not hope for a miracle technology.
https://sf.curbed.com/2019/3/19/18273029/milpitas-odor-studi...
https://www.clf.org/blog/all-landfills-leak-and-our-health-a...
https://pubs.usgs.gov/fs/fs-040-03/
Plastic in a landfill is just... Stuck there. It's unnatural, sure, but it's not immensely harmful, not nearly on the same scale as CO2, and realistically, in the future, we'll be able to mine it out of there and refine it into something usable if we need it.
[0] https://www.greenpeace.org/aotearoa/publication/ghost-gear-t...
https://www.nature.com/articles/s41598-018-22939-w
https://en.wikipedia.org/wiki/Breeder_reactor
Nuclear waste is also extremely compact.
Unfortunately our world is not run without the consumption of resources. There are trade offs to everything.
I don't think you realise the VAST amount of energy density in one 1kg of coal vs 1 kg nuclear fuel. "Somewhat" is not nearly the correct comparison !
"8 kWh of heat (energy) from 1kg of coal vs 24,000,000 kWh from 1 kg of uranium-235" [0]
[0] https://www.euronuclear.org/glossary/fuel-comparison/
The caveat is of course that for 1 kg of coal you have to dig up a lot less material than you have to for 1 kg of fissile material - U235 is around 1 % of natural Uranium, and Uranium is around 1 % of the ore.
Maybe this is just a joke that sailed over my head, but this is obviously false and doesn't mean anything of the sort. Existential for whom? All you can definitely conclude is that the Earth won't explode if the climate increases by 15 degrees. You can guess that life would survive, but there were no humans back (or large mammals at all) back then. There's no reason to think we would make it.
> The people controlling the media won’t allow it. This is common knowledge.
This is just rank conspiracism. I know of no evidence to suggest that the media are somehow controlling events (?), laws (?), the "narrative" (?), simply to prevent nuclear reactors from being built. How? For what purpose?
And claiming "this is common knowledge"? Maybe that was just another joke, because normally when one says a conspiracy theory is true, one also claims that this is secret information that has to be carefully mined out of various data sources, because if everyone knows something is happening it's usually not a very good conspiracy.
If a country has sufficient nuclear energy then they are immune from international energy politics.
Two, I see that the oligarch class is using global warming alarmism as the driving narrative to move everyone to a carbon credit system, where payouts go to an unaccountable transnational elite.
Ironically, I believe that once the incentive structure is in place, there will be institutional force to keep you buying carbon (offsets) credits… forever.
It's the flaw that makes reducing global warming a talking point vs an actionable item. It's a big elephant in the room.
Until that gets resolved many will think some are spinning your wheels.
If the CO2 levels spike, life on the planet (including many or maybe even most humans) will survive. If you look at historic levels, they were hundreds of times higher and the planet was the greenest it has ever been.
If/when that toxic waste leaks out and starts killing, NOTHING will survive.
And the thing is that these are actually harming the people who are near the area where they are disposed, so the harm is more direct. CO2 is more like a global problem, so not as worrisome for the local population.
Only if you're talking about Putin's Little Green Men, in which case most were last seen heading to their deathbed in Belarus after having exposed themselves to deadly levels radiation after occupying the area and trenching it, to the total dismay of local Ukrainians and Plant workers!
Life does indeed find a way, but not in the way most think.
> In a way radioactivity is one of the easiest contaminants to deal...
What an absurd statement, if that were the case you'd go live and work in Fukushima and take advantage of all the open area and low cost real estate, and all the plentiful food that comes from that region.
Radiation to this day still hasn't been cleaned up in Chernobyl, which happened almost 40 years ago, and an Evacuation Zone is still in place.
And by the way their is an ongoing fire in the area as we speak that is cause for concern [0].
0: https://www.republicworld.com/world-news/russia-ukraine-cris...
We leak it all over the place, with no plans to plug the holes. Instead we keep adding new piping all over.
You have my sympathies for going through a this procedure even though I never had to do that.
But I'm sorry you've put such an important emphasis on having kids in your relationship. The fact that you live in a society where that's reasonable is immensely sad, to me.
You should feel whole without children, and the fact that you don't is the real tragedy, IMO.
Are you always this antagonistic and reductive?
Every couple of years this concern bubbles up. It seems to be established that sperm counts in males are going down. But I’ve yet to see substantial evidence about the possible causes. The effect of plasticisers e.g. were found in animal models usually with rather high doses. An increase of obesity over the last 50 years might also be a likely cause as obesity is linked with hormonal issues. Furthermore, the average age of first time parents has increased significantly. That could also explain why IVF got more popular as sperm counts (and egg „quality“) are age dependent as well.
AFAIK there is no empirical study today proving any link between environmental issues and sperm counts.
Apparently it's happening in dogs too: https://www.sciencedaily.com/releases/2016/08/160809095138.h...
But not necessarily in farm animals.
We know for a fact that phthalates have an effect on embryo development, and good luck avoiding those.
So while yes, for people it may be less of an issue, the same cannot be said for wildlife, where it becomes another nail in the extinction coffin.
> Per the most recent Inventory Report, U.S. landfills released an estimated 109.3 million metric tons of carbon dioxide equivalent (MMTCO2e) of methane into the atmosphere in 2020; this represents 16.8 percent of the total U.S. anthropogenic methane emissions across all sectors.
https://www.epa.gov/lmop/frequent-questions-about-landfill-g....
https://www.epa.gov/sustainable-management-food/sustainable-...
A very large fraction of those are from plastic waste in Asian countries that gets dumped into waterways instead of being landfilled.
But if you do, the smell, view, and fact that ground water becomes undrinkable will convern you. Not to mention the space they take, where little life can live on.
In the USA, you have a huge space, including deserts, so a landfill may be out of most human reach. But in France, landfills can't be far, and take the place of either a forest, or accomodations.
We don't have a better way to deal with the huge amount of trash than landfills for now. But reducing the number or size of them would be a nice to have.
I don't mean it should be a priority compared to most urging issues like climate change, but let's not get too comfy with it either.
Not even going to get into plastics being contaminated by toxic things and leeching chemicals. Landfills are not harmless to ecosystems and aquifers, either- they're a short term way of not dealing with the issue of waste materials, at best.
> ...and a circular carbon economy for PET is theoretically attainable through rapid enzymatic depolymerization followed by repolymerization or conversion/valorization into other products
> Finally, we demonstrate a closed-loop PET recycling process by using FAST-PETase and resynthesizing PET from the recovered monomers. Collectively, our results demonstrate a viable route for enzymatic plastic recycling at the industrial scale.
[0] https://www.nature.com/articles/s41586-022-04599-z
Thus, successful recycling of plastic would mean less new plastic being made, and less emission. Before renewables, petroleum not made into plastic would instead be burned as fuel. But now, or soon, maybe it will be left in the ground, instead, as not worth pumping out. It is better to leave carbon sequestered where it is than to extract and then sequester it.
Not saying it's good, but burning plastic if it has environmental and health benefits is not out of question. Probably most of it is burned already (it definitely is in Asian countries).
Germany seems to have invented the term "thermal recycling", i.e. burning plastics. IIRC, it is actually considered a renewable energy source by the law.
It's not the worst idea per se, if done right, and waste separation is actually significant here because it simplifies calorific value control.
A pen presumably gets hundreds or thousands of uses, depending on how you count. For example, one way product packaging is much more of a single use plastic.
That being said, I’d hate to lose plastics for bulk food packaging, unless there’s an equally food safe successor.
Will car plastic interior start to rot?
Will PET soda and water bottles start decomposing in the grocery store, and will they require refrigeration to prevent that?
Will our computer keyboards require new materials?
PET soda bottles will be sterilized, then sealed. The outside is dry and won't decompose. You won't be able to re-close it and leave it out though.
For things that need to stay wet, like drain pipes, you would add chlorine and use PVC which is unlikely to be edible to bacteria.
https://en.m.wikipedia.org/wiki/The_Andromeda_Strain
https://en.wikipedia.org/wiki/Gray_goo
Obviously we want plastic to eventually biodegrade, but I wonder what sorts of chaos would be caused by it.
BBC Science in Action [1] interviewed Prof John McGeehan of the Centre for Enzyme Innovation at Portsmouth University working on Bacteria breaking down Plastic in landfills. He explained his workflow of maybe selecting one candidate very carefully and occasionally out of many due to the cost/time involved & how DeepMind gave him more results in a single weekend (for free) than he had expected to see over his entire reasearch career.
[1] https://www.bbc.co.uk/sounds/play/w3ct1l3y
What does that mean?
I assume nothing will happen while this "news" will be used by fossil fuel companies to virtue signal "technological progress" in the plastic problem.
Seems to be one of those things where, if you're not in the field, all the news is the same and sounds like a breakthrough, but it'll be 20y out from actual adoption for a while.
Everyone wants a quick fix for climate change and pollution because it will absolve us of doing the hard work that the problem really requires. By all means, we should pursue such moonshot ideas - but like you said, it will be used to virtue signal some false idea of "progress" while the problem gets worse.
But it's definitely worth exploring those moonshot ideas, so I'm not shutting that idea down. It's just good to be aware of how these sorts of headlines are used in the service of greenwashing.
https://www.goodreads.com/book/show/2368220.Mutant_59