The Plastic Problem

 All of us are aware that disposing of plastic is a big problem.  We are bombarded by stories of plastic ending up here and there, basically in all the wrong places.  It ends up littering streets.  It can be found in parks, rivers, the ocean, everywhere.  We have "The Great Pacific Garbage Patch".  We have critters, cute and otherwise, getting tangled up in it.  The list goes on and on.

The problem is that the stuff is just too convenient.  A few years ago cosmetic makers found out that adding "microbeads" of plastic to cosmetics enhanced characteristics consumer like.  The result is microbeads everywhere.

Clamshell containers for fast food and disposable tableware have made a comeback as a result of COVID.  COVID also caused single use plastic bags to reappear in grocery stores for a while.  This is in spite of the fact that they were outlawed a few years ago.

Plastic.  We love it.  We hate it.  We love to hate it.

Various efforts have been made to ban plastic in a few narrow situations.  These have seen some success.   But all of these efforts together represent a tiny fraction of all the plastic that gets used.  Not surprisingly, the number of tons of plastic produced continues to go up every year.

Various efforts have been made to push recycling.  I commend them.  But they too are a niche solution.  The reason is thermodynamics.

There are three laws of thermodynamics.  I'm not going to even bother to list them.  They are laws because it is literally impossible to violate them.  And what they say is "we're doomed - doomed".  Why?  Because of a concept I am going to talk about called Entropy.

We all know something about Entropy without knowing we do.  Imagine a bag of black marbles, a bag of white marbles, and a jar.  Pour each bag into the jar.  The result will be a layer of one color, say the back, on top of a layer of the other color, say the white.

Now reach your hand into the jar and stir things up.  The result is that the layers disappear and all the marbles get mixed together.  Now, how do we get back to the previous situation where the marbles are separated into layers.  It turns out that it takes a lot of work, far more work than it took to stir things up in the first place.

Entropy is a precise scientific version of this.  Entropy is the measure of disorder in a system.  The original setup where the marbles were organized into layers was a low disorder configuration.  As a result it had low Entropy.  The later configuration where the marbles were mixed together is a configuration featuring more disorder.  So, it has higher Entropy.

That's the basic idea.  There is a whole branch of science for dealing with all of this.  The Entropy of a system can be calculated.  That means that the difference between the Entropy of one configuration versus another configuration can be calculated.  Not surprisingly, this process is very complicated so I am not going to go into it.

What Entropy does for us is that it allows the laws of Thermodynamics to be restated in terms of Entropy.  And when we do that the result is a single law.  The Entropy of the whole system always increases.

Now it is possible to drive the Entropy of a part of the system down.  But to do so we must drive the Entropy of some other part of the system up.  And, if we add all of the changes in Entropy together, we always find that the grand total increases.

So what's that got to do with plastic?  It means that things like recycling are doomed to failure.  They can be made to work with one or another small part of the system.  But, if you look at the system as a whole, more chaos will be added to the system as a whole than the chaos we are able to remove in this or that small corner.  And, in this context, chaos and garbage are the same thing.

What's garbage?  It's a mish-mash of all the things we don't want anymore.  Generally speaking, when we first get something it is neat and tidy.  When we are ready to get rid of it it is messy.  It's all tangled up.  It's broken.  It's dirty.  The things we start with have low Entropy.  The things we want to get rid of have higher Entropy.  This definitely pertains to plastic.

Take microbeads.  A shampoo maker buys a large container of them from a supplier.  The container is full of microbeads.  They are all the same.  That's how you know that the Entropy of the contents of the container is low.  Now the manufacturer mixes the microbeads with some other ingredients and puts it into a bottle.  Imagine trying to fish all of the microbeads back out at this point.  It is impossible.

But it gets worse.  Someone buys the shampoo and uses it.  Most if it, including the microbeads gets washed down the drain where it gets mixed with a lot of other stuff.  It is now even harder to separate the microbeads out.  But then the bottle, still containing a small amount of shampoo, which contains a still smaller amount of microbeads, gets thrown in the trash.

The trash gets picked up and goes to a landfill.  What's in the landfill?  Lots of different kinds of stuff, almost all of which is not microbeads.  The garbage in a landfill has a very high amount of Entropy.  Extrapolate this analysis to all the other kinds of plastic.

People try to help.  Seattle, the city I live in, ran an experiment many years ago.  They had people separate out the trash they were recycling into paper, glass, and everything else.  This made a lot of sense from a Thermodynamic/Entropy perspective.  But they soon went to a simpler system.

It turns out that it cost a bloody fortune to have special trucks and the other infrastructure that they needed to keep everything separate all along the way.  It was cheaper to go to a single bin and hire people to separate it out at the end.  That's what they have done ever since.

But to be able to recycle stuff it has to be separated out.  Paper has to be separated into several specific types, one of which is cardboard.  Metals have to be separated into copper, aluminum, etc.  The same applies to plastic.

And in all cases if it isn't pretty clean it can't be recycled.  And even if it is clean, lots of kinds of paper or metal or plastic still isn't worth recycling.  It's cheaper to dig more of something up, or pump it out of the ground, or plant and harvest more of it, or whatever.  If the recycled feedstock isn't cheaper than new feedstock it is not going to be used.

We have been recycling for a number of decades now.  There are some successes.  But mostly it is a failure.  There is no general category of material, something like paper,  for which, as a whole, it pays to recycle.  This is definitely true for plastic.

Plastic packaging often features a "recycle" symbol with a "category" number inside.  Lots of people think that the symbol means that that kind of plastic can be recycled in an economically viable manner.  But several categories can not be recycled at all.

And other categories can theoretically be recycled.  But costs are too high to make the process practical.  And recycling is only practical when it comes to clean and pure material.  If the material is dirty or consists of a mix of types of plastics then it can't practically be recycled.

Most of the material that is tossed out is neither clean nor pure.  The typical "blow mold" bottle that pop, and so much else, comes in is pure.  But the bottle cap is made from a different kind of plastic.  The bottle and the cap (including the little ring that is left after you open the bottle) are made up of two different kinds of plastic.  They need to be separated so that they can be processed differently.

And so it goes.  Thermodynamics and Entropy are why recycling have made such a small difference when it comes to garbage in general and plastic in particular.  So what should we do?  I have a solution that I guarantee no one will like.  Burn it.

At this point Global Warming people are reacting in shock and horror.  And I can't blame them.  Burning millions of tons of plastic will add millions of tons of carbon dioxide to the atmosphere.  That will make Global Warming worse.  They are right.  But the problem is even worse than that.

Plastic consists mostly of carbon, oxygen, and hydrogen.  Carbon and hydrogen combine to make water.  Carbon and oxygen combine to make carbon dioxide.  One is harmless, from a Global Warming perspective.  The other is not.    But beyond that there is the "mostly" part.

Plastic contains small amounts of other elements.  Burning plastic creates oxides of nitrogen, chemicals containing chlorine, some of which are quite nasty, and more.  The types and amounts vary with the specific type of plastic.  Something needs to be done about them.

Burning plastic causes all kinds of problems, the most obvious one being the carbon dioxide it produces.  So why consider even doing it?  Remember the adage about the perfect being the enemy of the good.  This is a case of the bad being the enemy of the awful.  Consider what we are doing now.

We can see the harm that throwing away (or pretending to recycle without actually recycling) plastic causes.  A lot of very smart and very talented people have applied themselves to the plastic problem.  They have yet to find a "good" solution that actually works.

Recycling is as close as they have come.  We pretend recycling can solve all, or a large part, of the problem.  But all it can do is make a small positive difference.

So, given my precious discussion of Thermodynamics/Entropy, why do I recommend burning?  Because Thermodynamics/Entropy says that burning can work.  Plastics are energy intensive.  Burning allows that inherent energy to be used to break the complex chemicals in plastic down into simpler chemicals.

A full accounting of the Entropy involved would show that burning plastic results in a big increase in Entropy.  But most of that increase happens somewhere or somewhen else.  Inside the incinerator the Entropy of the materials actually decreases.

It should be obvious by now that we don't want to just pile up a bunch of plastic and toss in a match.  We need high tech incinerators.  They need to be able to safely contain the nasty chemicals that are produced.  We also need to figure out what to do with the carbon dioxide.  I think that both of these problems are solvable.

But once the technical problems are solved burning can be applied to most plastic waste.  Plastics contain a lot of energy in their chemical structure.  So we can combine lots of different kinds of plastics and the incinerator will still work.  And the plastic doesn't have to be very clean.  If the contaminants burn, so much the better.  If they don't then they will just settle out as ash.

Incineration represents a practical high volume solution to plastics.  It doesn't work for all plastics, microbeads in the sewer system, for instance, but it works for lots of plastics.  We do need to develop high tech incinerators and we do need to figure out how to deal with the carbon dioxide.  But I think those are solvable problems.

If burning plastic is an unacceptable solution then there is only one other workable alternatives.  That's landfills.  We can just pile it up and try to ignore it.  That's what we are doing to a great extent now. 

But we will need to greatly expand these landfills, and we need to be honest about what we are up to.  These landfills will be full of nasty stuff.  And they will sit there virtually unchanged for thousands of years.

We also need to heavily subsidize the process.  People do not properly dispose of a lot of stuff already.  They do this because they consider the current system inconvenient or expensive.  That means, if we are going to stick with the landfill route, we need to make it easier and cheaper for people to handle plastic (and lots else) in such a way that it actually does end up in a landfill.

So there really are two practical possibilities:  Landfill and burning.  A landfill just delays the inevitable, perhaps for thousands of years.  So, it is important to keep in mind it's not a fix, it's just a delay.  Burning, if the technical kinks can be worked out, represents a real solution rather than a pretend one.