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Someone interested in recycling got me googling around for, give or take, home recycling setups, and I found a site that’s essentially exactly that: preciousplastic.com.
It’s really a pretty neat idea. There are fairly detailed plans for a number of machines that show you just how low-tech plastic recycling can be. There’s a shredder for ripping old plastic into reuseable chips. There’s a hand-powered injector for melting chips and shoving them into a mold. There’s an extruder for melting chips (a common theme) and pushing them into, well, any extruded output, from 3-D printer filament to boards. And there’s a “compression machine” for forcing heated, pliable plastic into a larger mold whose output is formed through, yep, compressing the crud outta that plastic with something like a car jack.
Plastic Recycling: The Bad Parts
Now once you start doing some research, you find that the machines aren’t necessarily as wonderful as you might dream. The shredder apparently jams quite a bit, and has a hard time handling a range of inputs. The injector described, for instance, is labeled discontinued/abandoned on a sister site, and there are complaints that it’s difficult to make the lever pull straight. You also, it turns out, have to wait 30 mins for the chips to melt before each “shot” is ready for injecting, so even if you pay to machine some good injection molds, you’re only making a few small items every 30 mins in your best case. Neat as a sort of proof of concept or art project, but not exactly business plan ready.
I’ll also complain that the “Bill of Materials” charts are pretty crummy. They are definitely written for someone with more knowledge and time than money – which is fine, to a point. But when half the items say you should pick them up at the scrapyard, well…
There was also apparently a โฌ300,000 grant awarded to the project (good!) but then squabbling started between two locations researching machines and (maybe?) the money wasn’t spent, um, wisely (bad!). You can see some of the culture wars in this thread on creating a double-axis shredder…
we already tried everything possible but eindhoven [a town where one group of Precious Plastic-ers is based] seems to use itโs [sic] goal keeper position to deny/refuse any sort of improvements, no matter the gravity or urgency or realities coming with it. anyway, donโt worry, we started building a new site pointing out all the numbers/fixes for v3.
(The account that posted that has also been removed.)
By now, if you are local, you know that Kristin and I left Circle Acres. … A strong sense of misplaced entitlement pervades that place, which is something that I cannot support in any way. Living rent free while someone else carries the financial water is not anarchist, not friendly and not nice. The others may argue that this isnโt the case, but all I have to do is read through old emails and bank records to see how things went down, get a glimpse of what should have been some serious red flags and see that I made many mistakes in making a path for this coddled land project.
Apologies for the aside, but the connection, I hope, is that idealism only gets you so far. At some point, the plastic hits the road or the nails hit the soil, and sometimes it’s easier to squabble than be realistic.
That is, it’s very hard to ramp up some clever proof of concepts into something competitive at scale, no matter how well intentioned the originators.
Quick impressions:
The Precious Plastic machines are neat proofs of concept, but nobody’s done this at scale long enough to create reliable machines, must less cost-effective ones.
The emphasis on something you could build in the “3rd world” is laudable. That is, there’s a desire to move things away from lots of CNC stuff to things that you can find more easily.
After spending a little time researching this, you'll never be able to look at single-stream recycling the same again. There are good plastics, like HDPE #2, in milk jugs and clothes detergent containers, that’s high value, and maybe a little less so the #1 stuff in soda and water bottles, etc. Then there’s the rest of this stuff, much of which is outright trash. And even some of the #1 and #2s are no good to your single-streamers. Observe…
The City of Minneapolis' Acceptable Recyclables page does a good job showing that not all recycling is gold.
“No #6 plastics (polystyrene: rigid or foam)”
“No black plastics (any number)” <<< This one is especially interesting (see also the MEILO video, below)…
Plastics are sorted by type (number) at the recycling facility by a laser. The color black absorbs the laser light and does not allow it to identify the type of plastic an item is. Black plastics would have to be pulled by hand and a person would have to look at each piece to identify if it is a #1, #5 or #6. These logistics, including the weak markets, make recycling black plastic not economically feasible. [emphasis mine]
I also like this YouTube video of a German recycling plant as the perfect embodiment of the idealistic, almost-magical, view of single-stream recycling. But if you watch closely, you see this is an engineering solution in search of a problem, and can't really be the smartest way to recycle.
MEILO, a company in Gernsheim located in southern Hesse, sorts plastic trash from the yellow barrels in 30 repetitive sorting processes until the maximal purity of variety has been attained. Plastics are first separated according to size and then subjected to an air separator. In the following step, a near infrared scanner scans the plastics on the conveyor belt as they pass, communicating to a compressed air jet at the end of the conveyor belt which plastics are recyclable. Finally, the compressed air jet blows these material aside. Thus, varying plastics are sorted by an up to 98% purity of variety. In addition to the three major valuable plastics, HPDE, PP and PET, four other well-recyclable plastic varieties are gleaned from the river of trash.
But look at the products in the end! There’s this implicit goal of finding clear plastic – check the picture of the shredded flakes "output", below – and the bottles being made are perfectly clear – also below. Unless there’s a way to bleach plastic (which, as someone who knows a little about bleaching pulp and paper, sounds like a horrible idea), that giant German machine can only give this bottle-making company some insanely small, "highest-quality" percentage of the plastic that’s thrown into the recycle bin (and don't miss the importance of the 80% of the recycled content of the bottles is pulled from the "deposit system" -- a "separated stream" source of plastic; that's key, and all but proves my point).
What do we do with the oranges and blues and greens, much less the black plastic Minnesota tells us is practically worthless to these systems?
The pictures in the news of people in local-income areas in their homes, sorting plastic trash (great picture from NatGeo here) in countries that take our plastic waste make more sense now. This is valuable work precisely because there's such a range in the value of specific plastics – clear over colored, #2 over others, eg – versus the single-stream input we’re sending overseas.
I mean, look, in the US we’ve all seen – and some of us probably collected – aluminum cans off the side of the highway for cash or fundraisers (which is also for cash, remember), and we’re one of the richest countries in the world. If there’s any value in plastic, of course people with lower wages are interested in finding and sorting for the “good” plastic.
This also explains why there’s so much trash in countries that take in the waste. This excellent Guardian article does a wonderful job reviewing what’s happening.
Experts estimate that 20% to 70% of plastic entering recycling facilities around the globe is discarded because it is unusable โ so any plastic being recycled at Sihanoukville would inevitably result in more waste there.
It’s weird and obvious when you think about it:
A trade deficit with China means we have more containers full of high-priced stuff coming in to the US than going out.
So we basically have empty containers ready to ship anything to somewhere near China for rock-bottom prices.
Trash has some value (ever been to your local landfill? You should go. It’s magical), so we ship it out.
But that number – 20–70% (an insanely large range, btw. Come on, Guardian!) – of what we send is still just trash. (This is, btw, why China stopped taking our stuff.)
If the country that receives it does a bad job with its own waste, what makes us think that 20–70% of what we send is going to be handled any more responsibly?
It also tells me, again, that single-stream recycling is INSANE.
We have our plastic goods separated at home. Don't commingle them!
Quit the aspirational recycling, throw away the trash.
Put the orange-ish detergent containers in one pile, the nearly clear milk jugs in another one, the clear soda bottles in a third, etc.
Overall, this episode of Penn & Teller's Bull[crap] on recycling is pretty bullcrappy itself (it's the worst sourced, most incomplete persuasive "documentary" I've seen since I TA'd), but if it did nothing else, it showed us that humans take pleasure from separating things into groups.
It also tells me we’re wasting a ton on shipping around trash. Curbside pickup to the landfill is bad enough. Then find the places that can actually use this stuff. In the US, how far are you from an end-producer? And shipping to Asia? Good heavens. How far are you from a western US port? I know it’s all but “free” once it hits the boats, but the opportunity cost. What if we just shipped clear #1? How much more could we ship without contributing to the unmanaged junk in a third-world recipient? Imagine how excited the companies that can use that type of plastic would be that we eliminated most of the real trash?
The obvious take home for me is that if you could recycle well separated, high-value plastic into usable, lasting products locally, you’d be doing a real service.
Plastic Recycling: The Good Parts
So let’s get to the good parts of how to create home-grown recycling industries that I want to come back to later. The injection machine, even though there’s a neat 3-D rendering of an iPhone 7 & 8 case in Precious Plastic’s downloads that you could send to your local contractor with a CNC router, ultimately seems impractical for making a real-world dent in plastic waste, so I [re]started with extrusion.
If you could get, clean, shred, & create boards (ie, use lots of plastic) and turn them into something useful, well, maybe you could help close the local circle on very specific types of plastic by creating those interesting and lasting products.
Here’s some of the stuff I’ve found that I’d like to come back to later.
Extruder development v4 - includes example beams and a new parts list (look for jovinc 15/05/2019 AT 15:52)
Furniture talk -- talks about making chairs from beams. Note the emphasis on PS: "Can we use it in other materials than just PS?" Bizarre. I would've thought HDPE was best, like, um, in this chair sold at Costco.
Some results… though I wonder how strong these boards are. The cross-sections and rough outsides of the 2x4 looking boards scare me a little. I’d like to have some to play around with.
Dave Hakkens (Precious Plastic founder) extruding some beams (that look quite good, honestly).
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