Garbage In, Toxics Out | Hacker News Reader

Garbage In, Toxics Out

theintercept.com

49 pointsschlowmo23 comments

The problem is with trying to "recycle" garbage plastic. Plastic is mostly carbon, oxygen, and hydrogen. Properly burning it using high-temperature (900+°C) pyrolysis converts most of plastic into water and carbon dioxide. There are some issues with sulfides and nitrogen oxides, but scrubbing those is a familiar problem for the industry. Remaining ash is relatively inert and can be used as a filler in various applications. Releasing carbon dioxide is not great, but it's much safer biologically than polluting environment and oceans with microplastics and total volume is relatively small compared to other emission sources.

I don’t see how sending plastics to a dump is going to result in ocean micro plastics. Environmentally you’re inefficiently generating energy from trash and reducing landfill size from bring trash vs failing to sequester the carbon in the trash and releasing some air pollution. I doubt pyrolysis is a net gain.

Properly constructed and operated landfills are a small source of methane, but otherwise quite benign.

"Properly constructed and operated landfills" which prevent leakage of microplastics and toxic decomposition products into air and waterways are far from being cheap, especially on longer time frames and with involved volumes (more than 80M metric tonnes per year just in US!). Usually, you either end up with slack maintenance, resulting in eventual pollution of the environment, or you export this waste into third world countries with significant amount of such "exports" ending in oceans.

And plastic does not stay inert in landfills forever either, it slowly decomposes, releasing products into environment (methane and carbon dioxide being most benign of those). Effectively, you get slower, less controlled and more dangerous (biologically speaking) "burning" which will be done for many generations instead of burning the stuff right away in controlled conditions.

Dumps are the ultimate expression of surface area vs volume.

A single 2200 acre landfill can handle 5 million metric tons per year for ~250 years. 80M metric tons isn’t a particularly big issue from an environmental or cost issue it’s all a question of collection and transportation to disposal sites not long term storage.

>I don’t see how sending plastics to a dump is going to result in ocean micro plastics

Because that tends to only happen in a few, what we consider, first world nations. A huge portion of the world does not have sanitary waste collection system, and therefore produces huge amounts of plastic waste that get into rivers and the ocean.

Of even in places with waste collection, an (un)healthy amount of plastics never make it to the trash. Blow off/run off from trash cans is one example. Another is direct environmental loss into the environment. For example washing your clothes releases massive amounts of plastics, unless you happen to buy only natural materials.

Plastic is both a wonder material, and a wonder mess. Using it in things like medical device sanitation is a net benefit for humankind, using it everywhere appears to have higher costs than expected.

An incinerator isn’t going to solve the lack of a waste collection system. It’s a completely orthogonal issue.

> Properly burning it using high-temperature (900+°C) pyrolysis converts most of plastic into water and carbon dioxide.

I'm a little confused. Isn't pyrolysis what the company said they were doing?

Do they know what pyrolysis is, and are simply lying about doing it, or is pyrolysis a myth?

It's not a myth, it's a basic chemistry and physics. Increase temperature enough and chemical bonds start breaking, transforming complex molecules into simpler ones. Go far enough and you will get bare ionized atoms, i.e. plasma.

But there are different forms of pyrolysis. In my understanding, the company uses lower temperatures to transform plastic into "synthetic oil" (i.e. mix of hydrocarbons instead of long polymer chains), which in theory could be used to synthesize new plastic. Only small part of plastic gets transformed into gas and burned. But this "oil" is much harder to work with than oil pumped from ground, so instead of recycling it fully, some of it gets discarded into environment, resulting in toxic hazard.

I haven't been a chemist in more than 40 years, but even I know that pyrolysis of plastics makes a horrible toxic soup. There is no way to recycle many plastics in this way, the chemistry to reuse this resultant material doesn't exist. All it does is reduce the volume of material, which you then have to put somewhere. Also, the volatiles you generate have to go somewhere, and I highly doubt you want to breath them. You may as well live next to a battery recyling plant that uses coal for energy and raises pigs.

Fun little bit of trivia about the part of the world where this plant is located: the eastern 3rd of the state is blanketed in a thin film of aerosolized pig shit, so you're closer to the current state of play than maybe you thought.

Why are we still not talking about plasma gasification?

https://en.wikipedia.org/wiki/Plasma_gasification

As far as I can tell, the only real "disadvantages" if you can call them that, are:

1. more expensive than throwing the garbage in a big pile somewhere

2. need to clean it from time to time

3. not necessarily a profitable business

Other than that, it can handle just about anything that's not radioactive, can be designed to produce 0 toxic byproducts, and can run at or at least only slightly below energy neutral. Plasma gasifiers can also consume a huge amount of garbage for their size, so much so that the US Navy is starting to put them on the latest generation of aircraft carriers.

Not building out more gasifiers seems to me a failure of the free market. Because it's hard to make it profitable, no one is doing it - when really we should just be building one or two near every major city and funneling all our garbage there.

In theory, we could build out enough to start working through all the landfills too.

I am glad you shared that link. I always wondered if we could just use plasma to get rid of waste. I figured it would be technically possible but prohibitively expensive, so I am happy to see the economics work out in some use cases. Skimming through the article, they mention that the plant needs lots of maintenance and frequent downtime, I am not sure how that would work out with the navy's high availability expectations for the carrier fleet.

I've pretty much given up trying to recycle plastic, and instead throw it in the trash. It's toxic to make (I think?), contaminates food and water when you heat it, and--apparently--can not be recycled safely or efficiently. I realize I can't remove it from life entirely, but I'm actively avoiding it where I can and replacing it as opportunity permits.

I've heard it said that plastic is better off sequestered in landfills than recycled, to reduce the amount of microplastics getting into the environment.

>I realize I can't remove it from life entirely, but I'm actively avoiding it where I can and replacing it as opportunity permits.

I realized this as well and have practically eliminated single-use plastics from my life except for those being those needed for health and safety reasons, like the blister packs that some medicines come in or bottles holding household chemicals.

Even with household chemicals, a strategy to minimize plastic use is to buy high-quality commercial applicators that can be reused for years and then purchase the product in bulk or concentrated form.

It isn't as easy as it should be, but at the same time it isn't difficult. It just requires time and effort.

When I discovered that bar shampoos and soaps that come in cardboard boxes contain the same ingredients as their liquid counterparts, and were less expensive because you weren't paying to transport water or mold a plastic bottle, it started a landslide of plastic avoidance.

I have been wondering for years why solar powered pyrolysis wasn't being used to recycle plastics. I thought it could reduce ALL plastics to an oil soup kinda like crude, which could then easily be separated by a distillery into various useful hydrocarbon oils for making new plastics/fuels. However now I'm starting to understand: the resulting soup is more toxic than crude and is difficult/expensive to distill, while the volatile byproducts that don't condense are another toxic liability. Bummer.

As suspected by many. But we should be grateful for actual reporting on it.

Was this not a problem with the older model of separated recycling (glass, plastic, and paper in separate bins), with plastic limited to numbers 1 and 2 only?

I'm also curious about if plasma gasification is a better option for plastics than whatever this process is.

Since the transition to electric vehicles will take decades (and some, like aircraft, may never fully make the switch), perhaps the synfuel generated from this pyrolysis can substitute for virgin petroleum. It could help make many parts of the world more energy-independent and less obligated to rely on the Middle East for oil.

The oil to make the original plastics has already been extracted, so it would be a carbon-neutral solution for the most part, especially if some of the plastics are burned to drive the process.

THe ultimate solution, though, is to lessen our dependence on plastic (Reduce), and completely eliminate single-use (Reuse).

I wonder how they make money. This sounds like grifters living off of government grants. I wonder how widespread the problem is of grifters taking government grants for fake green projects. Perhaps the country made the right move by not doing a green new deal after all. It looks like paying grifters to do science doesn't work very well.

So what if a few projects take money and go nowhere. GND was an infrastructure bill for the most part. The country's infrastructure is crumbling so might as well invest in new green infrastructure while employing the people who have been abandoned when all the factories closed down. (The situation in 2018/2019 when this bill was proposed was different than post-pandemic decoupling from China).

The legacy of GND is that it helped influence the Inflation Reduction Act so we sort of got to an extremely watered down version of what the original vision was.

If you call out the problem generally you get denounced as part of the problem. Consider the reaction to "Planet of the Humans". There was a PR full court press from all the environmental groups to try to prevent people from watching it by attacking the messenger and focusing on trivial things while avoiding the discussion about the message.

It's just one example. I'm kind of bitter about the lack of attention to the effectiveness of the green tech movement and actually focusing on reduction of resource use.

I doubt cleaning up everyone's mess will ever be profitable.

And no doubt having the government pay private industry invites grifters.

I think a proper solution will necessarily involve going further left, i.e. government-employed workers. People who can't pocket the difference by cutting corners.

This is so disappointing (but not surprising).

Many years ago there was a lot of press about a company call Changing World Technologies (https://en.wikipedia.org/wiki/Changing_World_Technologies) that touted how they could use pyrolysis to convert any hydrocarbon feedstock into fuel (garbage, sewage, etc).

It was going to be cost competitive and clean. Turned out to be not so much when their pilot plant processing turkey remnants stank up the town and shut them down.

The technology seems to be valuable, but it looks like capturing and containing emmissions is still not cost effective so they just dump it.

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