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Life cycle assessment of enzymatic PET recycling
- bglazer 4y agoWe really owe it to future generations to figure out effective, energy efficient plastic recycling. This seems to be a big step. The economic barriers are huge here, oil is going to be cheap for a while yet. That said, it is a bit concerning that this could escape into the wild. Plastics are harmful long term but it’s crucial to society that they don’t just start degrading.
- meltyness 4y agoIt's always been confusing why this isn't as simple as running the dishwasher.
- eru 4y agoWhy would you expect it to be?
- feet 4y agoSimple things are expected due to a lack of understanding of the complexity of the problem
- eru 4y agoFunny enough, even supposedly simple dishwashers are already marvels of engineering.
- meltyness 4y agoI mean there's food-grade paraffin and beeswax wax can act as a polymer that addition of heat will reform. I can remember thinking as a kid, "why can't we just melt all this crap down?" I guess call it indoctrination since reuse, conservation, recycling is something taught to kindergarteners, but even at face value the lifecycle obviously a cost -- trash management, elegance (due to litter, and bad packaging), the risks of petroleum mining/hydraulic fracturing, presumably greenhouse gas emissions, microplastic contamination, risks of sloppy chemical engineering/benzene contamination... all costs centered on crap that mostly sucks as a product to begin with... an idiotic matryoska doll of nested garbage. The requirements get tough at those scales, for the full life cycle I suppose, iterating on any component effectively is a lifetime of work. Oh you can melt it, what about nonremovable contaminants? how much energy input did that cost? I don't see any clear-cut solution except to eliminate subsidies at a solution-dependent rate.
- kingkawn 4y agoIt is crucial to society that we transition away from them almost completely
- peteradio 4y agoEnjoy your laptop made of bamboo.
- empyrrhicist 4y agoThat actually sounds dope.
- eru 4y agoApple laptops are largely made of aluminum, I think. There's some plastic in there, eg for the keyboard. But removing 90% of plastics would solve 90% of the problem they pose. No need for purity. (I'm just playing devil's advocate here. I don't actually think plastics are necessarily all that harmful.)
- midoridensha 4y agoThere are countless applications where anything other than plastic really makes no sense, or is quite impractical or even impossible. The idea of eliminating plastics is pure fantasy. Even reducing them doesn't make that much sense. The amount of energy needed to recycle metals is generally much higher.
- bglazer 4y agoTo what?
- happyopossum 4y agoThat seems highly unlikely, and with efficient recycling, completely unnecessary. There are a number of uses where plastic is the best solution - economically and environmentally.
- eru 4y agoWhy? What bad things do you expect to happen?
- maria2 4y agoWhy? Plastic is made from oil. Oil exists deep in the earth, more or less permanently. If we extract oil, convert it to plastic, and then sequester the plastic permanently, e.g. via a landfill, then that seems net neutral. Yes plastic ends up in the ocean. But most plastic waste in the ocean comes from recyclables shipped from first world to third world countries with poor refuse control.
- tedivm 4y agoExtracting oil is an expensive process that has environmental consequences, and storing plastic after the fact requires land and can result in plastic leaching into the environment. There are also other petroleum byproducts between extraction and having usable plastics. With that in mind being able to recycle plastic cheaper than creating it from oil would be an economic and environmental win. As a small factual change I can not find any evidence for the statement that most plastic waste comes from shipped recyclables. I'd love a source for that.
- maria2 4y ago90% of river-borne ocean plastic comes from 10 rivers in Asia and Africa: https://www.weforum.org/agenda/2018/06/90-of-plastic-polluting-our-oceans-comes-from-just-10-rivers/ https://www.weforum.org/agenda/2018/06/90-of-plastic-polluti... Almost all plastic recyclables in the US is shipped to Asia and Africa. It’s simply not profitable to process here. From the article: > Recently, however, China has made efforts to curb waste. > For years the country had imported millions of tons of recyclable waste from overseas, but a growing recycling burden at home prompted the government to shift its policy.
- feet 4y ago>Almost all plastic recyclables in the US is shipped to Asia and Africa. It’s simply not profitable to process here. >90% of river-borne ocean plastic comes from 10 rivers in Asia and Africa Sounds like it isn't profitable there either, so why are we shipping it
- eru 4y ago> We really owe it to future generations to figure out effective, energy efficient plastic recycling. Why do we owe it to the future? We can just stick the plastics in a land fill and deal with them later. They don't degrade (much) after all. Perhaps oil will become expensive enough, and recycling good enough, that it will makes sense to mine landfills in the future. (I agree that putting plastics in the ocean or so is probably not a good idea. But that doesn't mean recycling is the only alternative, especially when it doesn't make economic sense. Btw, most plastics also burn well. So waste-to-energy plants might also make sense.)
- gilbetron 4y agoGrow plants, use plants to make plastic, use plastic for all kinds of great things, bury used plastic deep underground forever as a form of carbon sequestration. Repeat. Recycling plastic is pointless.
- 0xTJ 4y agoThe title here on HN has been butchered into nonsense. The only possibility for "them", as written, is "enzymes", which isn't the case.
- gnicholas 4y agoI have one word for you: Plastics.
- teaearlgraycold 4y agoI wish I could give out HN Gold
- midoridensha 4y agoI assumed this to be the missing word based on my prior knowledge of recycling, petroleum, etc. Still, the title should have included this. How did such an obviously bad title get through the review process?
- gnicholas 4y agoIf you're referring to the scientific review process, the title of the actual article is even more opaque: > Sourcing thermotolerant poly(ethylene terephthalate) hydrolase scaffolds from natural diversity If you're referring to HN, there is no formal review process — it's just upvoting/flagging. If a title issue is caught early enough, the submitter can change it. Sometimes @dang comes in and cleans things up.
- amluto 4y agoIf this works on a feedstock of mixed, dirty plastics, I can imagine it actually being economical. Imagine throwing a bunch of waste plastic in a reactor. Some is PET. Some is HDPE. Some is polycarbonate. Some is polystyrene. Some is other random polymers. Some is “compostable” material, and some is probably a horrible mix of plant fiber and fluoropolymers. Some is bamboo that got mixed in by accident, and there’s also some bits of food and crayons and other debris in there. Add a mix of enzymes and apply the right temperature, humidity, etc. Out comes a mix of valuable monomers, various contaminants, and the enzymes that survived the process. And a whole lot of unreacted feedstock that simply wasn’t the right feedstock. If you can separate the valuables out of the output mix, then maybe this whole enterprise pays for itself. Otherwise actually obtaining a clean stream of PET to recycle seems potentially challenging.
- colechristensen 4y agoMany other countries have no problems at all separating plastics. If you want it done well in America you probably just need to add a small refundable deposit to every recyclable container. But much bigger than the inflated to nothing 5 cents of soda containers.
- stubish 4y agoEven well sorted plastics will still have food scraps attached, except in locations where it makes environmental sense to have people wash it first.
- formerly_proven 4y agoThe issue is that recycling plastics uses quite a lot of energy in itself, so it quickly becomes a net-negative over not recycling with current technologies, especially if you use a lot of tap water and generate a lot of wastewater cleaning it.
- ZeroGravitas 4y agoYeah, unfortunately that energy is currently, like plastics made from fossil fuels, so the same people paid to tell you recycling uses too much energy are the same people telling you that renewables don't work. It's almost like they want people to use more of the fossil fuels they sell.
- kshahkshah 4y agoAlmost two decades ago in undergrad a lab I worked in was working on this stuff. It hasn't happened yet, really, at scale. I think it will happen, I'm just wondering if nature is going to beat us to it given what I've heard about bacteria evolving to digest plastics in the wild.
- stevage 4y agoThere's a noun missing from the title >Enzymes that could make it cheaper to recycle ___ than make them from petroleum Should be maybe "plastic bottles and textiles"
- jeroenhd 4y agoSo far, the entire concept if recycling plastic has been invented by Big Plastic to appease consumers that started being worried about it years ago. Plastic is barely being recycled right now because it's simply not economical despite government investment to make up for economical shortcomings. Rich countries end up shipping tons of plastics to poor countries, where the stuff gets buried or burned despite promises of recycling. The few plastics that do manage to get recycled can only be recycled a few times because the quality degrades across the process. I hope this technology can fix the problem, but I've seen more of these revolutionary technologies in the news over the last decade. They all promise to make plastic recycling viable and say it's really going to happen this time. Only being able to recycle PET is a nice start but in practice humans absolutely suck at separating waste (and companies constantly mix plastic types, making it even harder if you really care). I don't see any way out other than reduction of plastic use. So far, the entire plastic separation and recycling process is built on lies and deceit to make consumers think they're being more environmentally friendly than they really are. I'd be amazed if this plastic recycling technology of the month will finally chance that.
- winReInstall 4y agoIt also gets dumped directly into the ocean from the recycling transport or dual use fishing ships. Who then fish and bring fish home.
- nickspicer1993 4y agoJust to be aware if you're in the UK your recycling does get recycled so you should definitely take advantage of splitting your trash into recycling bins, in my council they recycle 60% (not buried or burned). The rest is correct though and it will most likely be down-cycled, my personal strategy I have been using without going crazy is: - Home Compost bin (this gets rid of 90% of my waste and makes the next steps less gross) - split remaining waste according to my recycling program: cardboard, metals, glass, plastics, paper, e-waste - cardboard/paper about half goes into compost, rest should biodegrade so vaguely ignore and hope for the best - End of each week look at what it going into recycling (dog food containers, salad bags, sauce containers etc.) and try to find a zero-waste alternative or tell the company you are considering moving and if they have any plans to improve their packaging infrastructure Support policy change, if we can tax plastics (or any material) at the right level to include its waste and energy cost there are plenty of businesses waiting to be economically viable such as; collecting e-waste/batteries and retrieving gold, copper, lithium. Bioplastics for wrapping food, sauce packets. I am not an expert in this area, so would love other people to correct any mistakes, it's really hard to go zero-waste or think about the right way to solve this problem without getting overwhelmed.
- fredley 4y agoSciFi prompt: A future version of this enzyme that can render plastic down to digestible oils is engineered into gut bacteria.
- ycombinete 4y agoThere’s a South Korean “anime” called Aachi & Ssipak based on a similar premise: “Somewhere in the future, mankind has depleted all energy and fuel sources, however they have somehow engineered a way to use human excrement as fuel. People started to build the new city by making new energy with their excrement. Soon after, the city's leaders announced two legislations to generate and control the new energy; including installing ID chips in each citizens' anus to monitor the defecation level; providing an addictive juicybar to citizens in return.” (https://en.wikipedia.org/wiki/Aachi_&_Ssipak?wprov=sfti1 https://en.wikipedia.org/wiki/Aachi_&_Ssipak?wprov=sfti1)
- ZeroGravitas 4y agoThis is like the regular articles about some new fancy battery chemistry that will make EVs as quick to charge as an ICE. It's effectively misinformation, because EVs are already better than ICE and just boring improvements to existing technology will provide improvements over the next fews years and decades. But, a) people hawking a new innovation need to grab eyeballs, and b) people fighting the future have saturated the media with BS to stop progress on EVs, renewables, recycling etc. and those two things combine to become potent misinformation. Recycling is already cheaper than making things from petroleum. It only doesn't happen in places where people think they can push the cost onto someone else. They don't realise that they are someone else's someone else and will end up paying the price they think they have cleverly avoided. Amusingly, the voices that have said "recycling plastic is impossible" have been so succesful, that there's now democratic support in many places for just banning many uses of plastics. Which was an unintended impact of these petroleum fueled lies. They've recently switched to attacking plastic bans, by promising that tech like this, will make plastic recyclable in the future. Whether pro or anti recycling, they remain consistently anti-regulation.
- upsidesinclude 4y agoThere are obvious trade offs between the two technologies and some of those are unacceptable to certain buyers. But your points are just non sequitur. >...quick to charge... >...EVs are already better... For whom? In a city, with short trips and reasonable climate, then sure. You haven't provided any reason or information as to why what you are claiming is true. As for recycling, you may be surprised to know that in the US it has mostly never happened. Companies found that a simple arbitrage could be completed by shipping away "recyclables" to the third world. Recycling is a corporate check mark, so corporations pay a premium to add a "post consumer recycled waste" label on their product knowing American virtue & status signaling is powerful enough to make it a cost effecting advertising strategy. Nowhere have I found information indicating recycled plastics are cheaper than new petrochemical plastics. Plastic is unbelievably cheap.
- ZeroGravitas 4y agoPetrochemical plastics and ICE cars are heavily subsidized, both in the "here have some money we taxed" sense and in the "we don't care if you are destroying the environment and poisoning people, carry on and we'll fix that with tax money" sense. It's hard to have that conversation if people only care about their next months out of pocket payment. Google whether gas heating is cheaper than heat pumps and you'll find discussion about what is cheapest for ordinary people with the current fossil fuel subsidies. But any simple economic analysis shows it's obviously better to shift to heat pumps and well insulated homes and so sensible countries do that, and reap the benefits. You'd have to invent some insane conspiracy theory about how climate change wasn't even happening, and all the scientists are secretly conspiring to undermine society in order to stop that, but who would believe that?
- karol 4y agoWon't beat entropy. Next!
- BLanen 4y agoI totally haven't heard this story for 20 years already. /s Such stories were used explicitly by the fossil fuel industry at those concerned with the new plastics back when they were introduced. https://www.dw.com/en/plastic-recycling-a-myth-as-packaging-explodes/a-63622887 https://www.dw.com/en/plastic-recycling-a-myth-as-packaging-... I will still stand by the argument that recycling is impossible. Entropy can't be reversed in any way economically, chemically, or socially.
- eloff 4y agoThat’s ridiculous. We recycle all kinds of things. It has little to do with entropy, a lot more to do with can we make the process cheaper than starting from raw materials. With plastic the answer is mostly no so far, but these enzymes have the potential to change that, maybe. With glass, steel, aluminum, it’s cheaper to recycle than start from ore.
- deleted 4y ago[deleted]
- liminal 4y agoI want this in pill form to remove microplastics from my body! (I realize that's not what's being developed)
- based69 4y agoStill don’t understand why putting plastics into landfills is not considered carbon capture and promoted as more environmentally friendly than risking it being burnt or disposed of in the sea when shipped to developing countries for “recycling” A single valley in some remote area can easily swallow millions of tonnes of plastic Expensive, energy utilizing recycling processes seem less environmentally friendly while also leaving more fossil fuel available for combustion use elsewhere