this post was submitted on 31 Jan 2024
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Food waste can be composted, and depending on how much oxygen is present, you can get methane out of it. But it's more common to use composting as a heat source and a fertilizer source. Same thing with human solid waste, you can get a decent amount of methane out of it and there are toilets set up to do this. I've seen standalone portable waste-to-energy toilets, and I've seen integrated facilities that directly help power a building.
I'm not familiar with what you mean by "cold plasma pyrolysis". Typically pyrolysis means you heat something up until in breaks down, and if it's flammable you do it in a deoxygenated environment. When you do this with plastics, you get mixed shorter-chain hydrocarbons, which can then be refined and used as fuel. There's plenty of easily searchable videos on DIY pyrolysis setups where there's a compartment where the plastic is put to be melted down, a compartment around it where the fuel burns, and a tube from the plastic compartment into a cooler place where it will condense and drip into a storage container. I think the setup I saw used around 40% of the fuel it produced to sustain/repeat the process.
Honestly, I think this is a much better fate for plastic waste than being left exposed to the elements to turn into microplastics. Yes, it turns plastic waste into carbon emissions, but the bigger question for carbon emissions is how much oil is drilled and how much energy demand we have in the first place. I'd say it's even a better use than recycling it into more single-use plastics.
Related to this is CHP (combined heat and power) machines, which can use different settings to produce different combinations of electricity, heat, and (biologically-inert, sequestrable) charcoal.
Making hydrogen gas is an extra step that rarely makes sense. Because it combusts without generating CO~2~, and because it's often made from CH~4~, it's kinda gimmicky and easily greenwashed. The only time you want to use hydrogen gas is when it would have a situational advantage over other fuels, which are more energy-dense and portable.
From what I've been told it doesn't really have any issue with spewing fucking dioxins everywhere like the waste incineration power stations?
Why did Scandinavians build those then lol??
For sure. Isn't one of the biggest issues with it sorting everything out? Plastic waste contaminated with food has to be really common right?
I am not a chemist, but to my understanding, the hazards of dioxins would be mostly from PVC and PET, which are significant but not large fractions of total plastic production. That said, the higher the temperature of the incinerator, the more thoroughly the carbon double bonds will be broken.
I don't think food contamination is all that much of an issue, it would be fairly easy to wash off or just let it decompose. But in terms of sorting, you definitely want to make sure you're only dealing with one type of plastic at a time, because they all melt and evaporate at different temperatures.
Ugh yeah you'd still need to sort out the unsuitable / explosion inducing objects anyways but type of plastic is prolly really important :-/
Idk I usually think about manufacturing as like how expensive the labor is + training & education + access to technology + the reagents going in + overhead of facility + transport + electrical grid stuff + supply chain
as far as what is actually going on inside the big TRASH reactor I'm a bit mystified thanks
I'm not sure what you mean about "explosion-inducing". The fuel that is produced is explosive if the combustion gets out of control. Typically though, pyrolysis is a metal cylinder inside a metal cylinder, with a tube coming out of the central one.
As for operational costs of recycling or pyrolysis, training and education are a form of labor, overhead is just labor, materials are a proxy for labor, transport is a direct function of labor. It's largely a question of how efficiently you can use your time to collect the plastic.
Before the question of pyrolysis comes in, there's an opportunity for cottage industry plastic recycling.
Decentralized appropriate technology is a way to diminish structural power imbalance, reduce dependence on the imperial economy, have a more direct connection to the means of production, prepare for disasters ~~or PPW~~, and demonstrate that a sustainable lifestyle is viable for everyone on the planet. It's good, folks.
This is a relevant inspiration to start with.
I need to stop mixing in things I heard on the phone with stuff I read, but I meant like metal crap or things with pockets of air or other stuff idk when I meant explosion inducing
Cool site will check it out.
Yeah I had been thinking of that article to link in the other thread but I only posted the coppicing one
I think there are processes of de-oxygenating the compartment. A bigger concern is that thin deposited metal films like in some wrappers, or plastic on paper like in Tetra-Paks. Stuff like that is prohibitively hard to recycle, and might just need to get crushed and stored underground, idk.