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Comment by philipkglass | Hacker News Reader

This is scientifically very interesting but pretty much orthogonal to solving problems with plastic pollution.

The worms can't live in landfills. If you could separate the plastic before landfilling to feed it to worms, then you could just burn whatever separated plastic can't be recycled. (Yes, that releases CO2, but so does having worms and bacteria eat the plastic.) The problem with plastic as waste isn't that it is super-toxic or impossible to destroy. The problem is that it's mixed in with a lot of other kinds of waste. We don't need new ways to destroy polyethylene. We need ways to separate it from mingled waste streams or prevent mingling in the first place.

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>The problem is that it's mixed in with a lot of other kinds of waste. We don't need new ways to destroy polyethylene. We need ways to separate it from mingled waste streams or prevent mingling in the first place.

We already have these ways, they are called waste separation and recycling. As a German, I've been separating my garbage for as long as I can think back: Plastics, paper, organic waste and whatever remains as residual waste. In addition to that, we have separate bins for glass bottles, if there's no bottle deposit on them.

Residual waste bins are usually the smallest ones, so people are pretty much forced to separate their waste if they don't want their residual waste bin full after just one week.

It's always weird to me when I'm in another country and everybody just throws everything into the same bin, bottles included, just feels so wrong to me at this point.

Well, since you can't put food stained plastics in the plastic bin (or do you guys do it?), it has to go into the residual waste, and it's that way with many things.

> you can't put food stained plastics in the plastic bin (or do you guys do it?)

I believe this is something that varies.

>Well, since you can't put food stained plastics in the plastic bin.

Why couldn't you? If it's just stained it's not much of an issue after all the food is biodegradable and will just rot on its own from bacteria and insects.

There are some people actually washing out their plastic garbage to prevent bad smells coming from their plastic garbage bag. Imho that's a massive waste of water, just put the garbage bag somewhere where the smell does not bother anybody, the stuff is garbage after all so it's not supposed to smell like roses.

Lipids are an issue for the recycling process. Some people wash them yes, but then you spend more energy on washing than is saved by the recycling so it's kind of pointless.

Do you have sources? The paper cited in the article only tangentially talks about byproducts:

> The most frequent hydrocarbon bond is the CH2–CH2, as in PE (Figure S1B). Although the molecular details of wax biodegradation require further investigation, it seems likely that the C–C single bond of these aliphatic compounds is one of the targets of digestion.

Which seems to imply methylene(o) as the byproduct?

Also burning plastic releases more than just CO2:

> The most dangerous emissions can be caused by burning plastics containing organoch- lor-based substances like PVC. When such plastics are burned, harmful quantities of dioxins, a group of highly toxic chemicals are emitted. Dioxins are the most toxic to the human organisms. (i)

(o) https://en.m.wikipedia.org/wiki/Methylene_(compound)

(i) http://www.wecf.eu/cms/download/2004-2005/homeburning_plasti...

Yes, the combustion of PVC and other halogenated hydrocarbons can produce dioxins. This worm digests polyethylene, a halogen-free hydrocarbon that does not produce dioxins even if burned.

The article says "The analysis showed the worms transformed the polyethylene into ethylene glycol, representing un-bonded 'monomer' molecules." Methylene itself is an extremely reactive species that cannot be isolated outside of exotic conditions such as trapping in a frozen noble gas matrix.

Ethylene glycol has a short environmental half-life and is oxidized to simple compounds like CO2 and H2O by a variety of processes:

https://www.ncbi.nlm.nih.gov/pubmed/11302583

https://www.researchgate.net/profile/Gordon_Craig/publicatio...

I googled and Wikipedia said Ethylene glycol is also toxic to people and animals.

So like yeah it must have to go through some other process after the worms eat it. It sounds like it'll get really complicated.

Arguably, you could breed worms in a landfill, provided the detritus weren't packed so tightly; Living creatures are usually pretty good at finding foodstuffs among non-edibles.

The article implies that they are trying to synthesize whatever enzyme in the worms break apart plastic.

So it isn't necessary for the worms to live in the landfills. I imagine the idea is to start dropping the pools of the enzyme on the landfill, or something like that.

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