Environmental Question #27 [Removing Environmental Microplastics]

What are the best long term options to remove microplastics from the environment? Are there really any at all? 

Courtesy of Reddit user u/what_to_do_what_to_

Q: What are the best long term options to remove microplastics from the environment? Are there really any at all? 

Every few months I see headlines about a new organism that consumes plastic in some way but I also understand that "plastics", like cancers, aren't a monolith with a one size fits all solution. Then you see people cleaning up the macroplastics and shoving them into freshly made plastic trash bags that are sent to the dump. It seems like there isnt any real progress being made to reverse or even slow the growth of plastic pollution.  

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A: That's a very insightful question. Yes, there are long term options to remove microplastics, but they're expensive. There are already good filters available for separating microplastics from water, and filters will only improve with time, so removal of microplastics is certainly attainable with enough resources.

You make a good point about the collecting in plastic bags and landfilling though. The best method for permanent plastic removal is called pyrolysis, which is just burning something inside a sealed container (pyro meaning fire, and lysis meaning break, so "break down with fire"). The vast majority of plastics are flammable, and even the ones that aren't easily flammable will still burn if they are heated to a high enough temperature. When plastic is thoroughly burned, it breaks down into inert, nontoxic materials like carbon dioxide and water. However, for the sake of the environment we wouldn't want to dump all of that carbon dioxide into the atmosphere, so the fire would need to be contained within a sealed chamber, then the byproducts would need to be compressed into something resembling coal, which would then be buried into the ground. I really need to emphasize how hot this fire needs to be though, because if the fire isn't hot enough the plastics will only partially break down and the resulting partially broken plastic bits will carry their own toxicity.

I'm sure you can see the difficulty with this already. Filters, extremely hot furnaces, sealed burn chambers, and tools to bury the safely handled final product are all very expensive. I would love to live in a world where we invest in this kind of infrastructure as a society for the common good of ourselves and our environment, but I don't expect to live in that world any time soon. Today the most popular approach to pollution is to designate "sacrificial land," where toxic materials and garbage are dumped and allowed to ruin the local area for the sake of keeping other places safe. This is a much cheaper and more immediately practical solution, so while I don't like it, I recognize it's better than just allowing pollution to persist everywhere.