A Small Solar Wheel Might Solve the Ocean’s Trash Problem

When you consider all the ills facing our oceans, including rapid acidification, the bleaching of corals, and the accelerated die-off of some species, the one most puzzling is simple trash. Every year, humanity produces about 300 million tons of plastic. A chunk of it filters through the production and consumption life cycle and then, by virtue of storm drains and sewer pipes, ends up in the ocean. A year or two later, Earth’s circling currents bring that trash to one of five main gyres, where it swirls until its either broken down by sunlight and wave friction or, far more common, eaten by fish.

Cleaning up the junk has always been a challenge. For one, there’s an ever-increasing quantity of synthetics made, used, and tossed by humans. The biggest plastic gyre—known as the Great Pacific Garbage Patch (GPGP)—is also extremely far from most land. And even understanding the problem is an imprecise science. Estimates of the GPGP’s size tend to range from an island of trash “as big as Texas” to “half the size of the United States,” often changing by the day depending on how much the plastic spreads out.

But could the technology to clean up areas like the GPGP already exist?

Ocean current map

Map of ocean gyres by Andrés Cózar et al, Proceedings of the National Academy of Sciences

Since 2008, a developer named John Kellett in Baltimore, Maryland, has been quietly building a solar-powered wheel to clean up its iconic inner harbor. Baltimore sits at the mouth of several rivers, so trash finds its way to Baltimore (and then into the Chesapeake, and eventually into the Atlantic). The contraption, roughly the size of two school buses, is low budget. Floating booms corral the debris onto a conveyor belt, where its lifted out of the water and deposited into a floating dumpster. At peak operation, the wheel can remove 50,000 pounds of trash a day. And because it creates its own energy, the only required maintenance is to change the dumpster after its receptacle fills up every month or so.

The technology works for Baltimore. The next step would be a test run in the open ocean. Meanwhile, there are other ideas for similar automated clean-up robots, including one concept trying to raise money on Kickstarter that would collect trash in a V-formation. Another looks like a three-sided tennis stadium that would float around and filter plastic out of the water.

Still, when it comes to implementation, it’s a little tougher than just setting and forgetting a floating trash eater. There are the legal questions, like who owns the ocean, and who’s responsible for cleaning up trash produced everywhere, but mostly by coastal countries? And if humans are putting 6.4 million tons of plastic into the seas every year, will a 25-ton-a-day vacuum cleaner really make a meaningful dent? It’s important to prick and prod new technologies that make big promises, although it’s equally valuable to give small ideas leeway to hatch into bigger ones. Baltimore hasn’t quite solved the issue of floating trash, but it’s far ahead of anyone else who’s tried.