
Production, use, and fate of all plastics ever made - sergeant3
http://advances.sciencemag.org/content/3/7/e1700782
======
philipkglass
_None of the commonly used plastics are biodegradable. As a result, they
accumulate, rather than decompose, in landfills or the natural environment._

Plastics are not _readily_ biodegradable. Plastics buried in landfills hardly
biodegrade. Plastics that are buried under soil or that sink to the bottom of
bodies of water hardly biodegrade. There are a variety of biological processes
that degrade plastics that remain exposed to atmosphere or in upper layers of
bodies of water, particularly when enhanced by ultraviolet fragmentation of
high-molecular-weight polymer chains. I'd say more like "the commonly used
plastics exhibit variable and typically low degradation rates in the natural
environment, making it difficult to quantify natural breakdown of plastics not
recycled or incinerated."

Here's one of the most fascinating papers I've ever read, about biological
colonization and breakdown of floating plastic trash in the oceans:

"Life in the “Plastisphere”: Microbial Communities on Plastic Marine Debris"

[https://macaulay.cuny.edu/eportfolios/branco2014/files/2014/...](https://macaulay.cuny.edu/eportfolios/branco2014/files/2014/08/Zettler-2013-Plastisphere.pdf)

And an article about polyethylene biodegradation by thermophilic bacteria:

[http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2672.2005....](http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2672.2005.02553.x/full)

And an article that you may have seen before, about polyethylene degradation
by waxworm gut bacteria:

[http://pubs.acs.org/doi/abs/10.1021/es504038a?journalCode=es...](http://pubs.acs.org/doi/abs/10.1021/es504038a?journalCode=esthag)

If you search Google Scholar for polyethylene biodegradation rates you'll find
many articles. Some thermoset plastics and halogenated polymers are
effectively immune to UV, biological, and combined-effects breakdown. They'll
endure into deep time like ceramics. But the most common plastics do degrade,
albeit slowly.

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jzl
Skimmed it for information on recycling:

 _" There are essentially three different fates for plastic waste. First, it
can be recycled or reprocessed into a secondary material (22, 26). Recycling
delays, rather than avoids, final disposal. It reduces future plastic waste
generation only if it displaces primary plastic production (30); however,
because of its counterfactual nature, this displacement is extremely difficult
to establish (31). Furthermore, contamination and the mixing of polymer types
generate secondary plastics of limited or low technical and economic value."_

Interesting point about how hard it is to determine how much recycled plastic
displaces production of new plastic.

More statistics:

 _" Before 1980, plastic recycling and incineration were negligible. Since
then, only nonfiber plastics have been subject to significant recycling
efforts. The following results apply to nonfiber plastic only: Global
recycling and incineration rates have slowly increased to account for 18 and
24%, respectively, of nonfiber plastic waste generated in 2014 (figs. S5 and
S6). On the basis of limited available data, the highest recycling rates in
2014 were in Europe (30%) and China (25%), whereas in the United States,
plastic recycling has remained steady at 9% since 2012 (12, 13, 34–36). In
Europe and China, incineration rates have increased over time to reach 40 and
30%, respectively, in 2014 (13, 35). However, in the United States, nonfiber
plastics incineration peaked at 21% in 1995 before decreasing to 16% in 2014
as recycling rates increased, with discard rates remaining constant at 75%
during that time period (34). Waste management information for 52 other
countries suggests that in 2014, the rest of the world had recycling and
incineration rates similar to those of the United States (37). To date, end-
of-life textiles (fiber products) do not experience significant recycling
rates and are thus incinerated or discarded together with other solid waste."_

Sad to think how little is accomplished by recycling a plastic bottle.
Although that won't stop me from doing it.

~~~
nickbauman
The problem with plastics recycling is the kinds of plastics we choose to
produce in the first place. Design of plastic things should be done with the
intent of the plastic to _remain in the production stream_ from the outset.
It's called _Cradle to Cradle Manufacturing._

High quality plastics are designed to be recycled almost infinitely: we should
consider them technical nutrients to manufacturing systems. They should never
become waste hence never be downcycled.

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njarboe
Maybe just store everything in sealed landfills until it becomes valuable
enough for people to mine it. The abstract should break out the landfill
versus natural environment numbers, as they are very different end locations.

------
bpodgursky
Wouldn't we currently rather bury plastic underground than decompose it into
CO2?

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saosebastiao
_Reposting a seattle subreddit comment because it would be mostly relevant
here (we have trash / recycling / compost collection)_.

As a suggestion to all the robotics / computer vision / AI geeks out there:
Build an automated trash sorter with a very high degree of accuracy.

If you want the incentive, here it is. Everybody has 3 separate bins. By
having 3 separate bins, not only do we force lazy people to think about how
they classify their waste into those 3 separate bins, but we also end up with
3 different waste trucks driven by 3 different drivers back and forth between
3 different waste depots. And we still get it wrong, misclassifying
compostable things as recyclable, recyclable as trash, etc., forcing us to pay
for processing costs to sort out the 40+% of stuff that gets misclassified.

This adds up. Waste management is a $75B industry [0]. Let's break down how
money is spent, and how your system will help:

1) 55% is spent on collection. Your sorter can eliminate up to 2/3 of that,
but due to variant efficiency factors maybe it is only 1/2\. This is about
$21B in potential savings.

2) Treatment and disposal account for 20%. This includes remedial sortation
(fixing the problems created by people who misclassified their waste), type-
based sortation (things like separating glass from plastic, as well as
separating the different types of plastic). A good automated sortation system
will save at least 20% of these costs, resulting in another $3B in potential
savings.

3) There are unaccounted for missed opportunities. Sortation costs force us to
make compromises; instead of the more expensive sorting of thermoplastics from
thermosets, which would result in higher resale value, we sometimes chop them
all up and sell them as a lower valued aggregate for things like road asphalt.
I have no idea how much is missed, but I do know that recycled thermoplastics
have a resale value that is a good 10x higher than what they get out of that
chopped aggregate.

4) Additionally, we have massive landfills that have accumulated billions of
tons of trash that, due to oxygen starvation in landfills, isn't biodegrading
any time soon. If your system can extract valuable recyclable materials from
trash and resell them, you could meaningfully create a second-hand mining
industry with basically free land rights. I have trouble seeing anywhere less
than 10s of billions of dollars in annual market from this alone.

So there you have it. You can make everyone's lives easier, save us time, save
us money, save the environment, and you'll have the waste management industry
groveling at your feet at the chance to save them $24B a year, possibly much
much more. Do it already.

[0]
[https://www.gridwaste.com/news/2014/8/20/10l92d52vzaw1zdsf0z...](https://www.gridwaste.com/news/2014/8/20/10l92d52vzaw1zdsf0znubdqpttq7k)

~~~
TeMPOraL
I assume that trash sorter would be on the sorting company's site?

Because from what I understand, the whole idea of having individuals sort
their trash is stupid, and done either beacuse of cargo-culting
environmentalism, or just to make people _feel_ like they're making some
difference.

Centralized trash sorting seems like a _much_ more efficient solution (due to
the usual reasons centralized solutions are much more efficient than
distributed ones). In fact, many times I've seen the segragated bins on
streets being dumped into one pile on a single trash truck. Besides it being
more efficient this way, it's also safer - you generally can't trust regular
people not to screw up such a task, so some centralized sorting before
processing is required anyway.

~~~
msl
> Centralized trash sorting seems like a much more efficient solution

How is this supposed to work? Sorting trash into many containers takes me a
little more time and effort and pretty much exactly as much energy as putting
it all in one place. It also keeps the materials from mixing (that is,
becoming dirty). How would it help to first mix it all, compress it together
(which is pretty much required to keep transport efficient) and then sort it
again?

Even if you want to use a sorting machine, would it not be better to have
presorted ("richer", in mining lingo) input material streams?

~~~
TeMPOraL
You want centralized sorting anyway, because a waste processor:

a) can't trust that you'll do your sorting perfectly, and won't occasionally
throw e.g. glass into metals bin out of hurry, carelessness, spite, or while
drunk. And even if you are perfect, your neighbour isn't.

b) might want to change the segregation rules to better optimize recycling
process; you don't want to force an entire city to update their bins and/or
habits in lockstep with whatever the waste processor does.

Point a) means they _have_ to sort themselves anyway, at which point
individuals doing the sorting is just wasted effort.

~~~
msl
I suppose there is no point in trying to find rich ore deposits either? After
all, the ore has to be refined anyway.

Sure, the processor will want to seperate, say, aluminum from iron, and remove
any glass from either stream, but I am fairly sure that these tasks become
significantly easier if the stream does not also include diapers, orange peels
and wet cardboard

~~~
TeMPOraL
> _I am fairly sure that these tasks become significantly easier if the stream
> does not also include diapers, orange peels and wet cardboard_

My point is, they can't even trust the stream won't include those. General
population can't be trusted like that.

