Every year, millions of tons of plastic waste pour into the ocean, much of coming from about 1,000 hyper-polluting rivers. And with overall waste generation poised to increase over 75% by 2050, the problem is only set to worsen. A number of companies around the world have turned their attention to the problem of river waste, building various barriers, fences, and wheels that help to contain and remove trash as it flows downstream. The approaches range from trash-scooping solar-powered barges to stainless steel fences, and different rivers will necessitate different methods. Here are how three companies, Clearwater Mills, The Ocean Cleanup, and AlphaMERS are approaching the problem.Clearwater Mills' Trash WheelsBaltimore's googly-eyed trash wheels, the first of which debuted in 2014, are one of the original efforts to address river waste. Built by Clearwater Mills, the company's founder John Kellett was inspired to design the wheels after years of seeing trash pouring into the Baltimore Harbor after big storms."We have Mr. Trash Wheel, Captain Trash Wheel, Professor Trash Wheel and Gwynnda the Good Wheel of the West here in Baltimore," Kellett said, citing the names of the anthropomorphized wheels which have become minor social media celebrities in the city. Here's how they work. Containment booms are set up in a V-shape across the river, with rubber skirts that extend about two feet below the water's surface. This catches trash floating downriver and funnels it towards the "mouth" of the rotating water wheel, which is powered by the river's current and attached solar panels. As the wheel turns, it powers a conveyor belt that lifts trash and debris out of the river and deposits it into a dumpster. Attached cameras allow the team to monitor how full the dumpsters are."And when that dumpster's full, we have another floating barge that we bring with an empty dumpster. Take the full one out, slide the empty one in and keep picking up the trash," Kellett said. Overall, the four wheels have picked up a total of about 2,000 tons of trash and debris. Sticks and leaves actually make up the bulk of this weight, since plastic is so light, but the haul overall includes about 1.5 million plastic bottles, 1.4 million foam containers, and 12.6 million cigarette butts. Everything is then incinerated in a waste-to-energy facility.Additional trash wheels are planned for Texas, California, and even Panama, where local nonprofit Marea Verde has partnered with Clearwater Mills to build the fifth wheel in the family, named Wanda Díaz. This project is funded by the Benioff Ocean Initiative and the Coca-Cola Foundation, which together are supporting a portfolio of river cleanup projects around the world.The Ocean Cleanup The Ocean Cleanup is probably best known for its efforts to clean the Great Pacific Garbage Patch, an endeavor the company's young founder Boyan Slat started pursuing in 2013 after a TED talk he gave on the topic went viral. Now though, the company is pursuing a dual focus as it's built a series of river cleanup technologies. "Our goal is to rid the oceans of plastic, and the reason why we look at rivers is because we believe it's the fastest and most cost effective way to prevent further plastic from being emitted to the ocean," said Slat. The company's first river cleanup device, called the Interceptor Original, was released in 2019. It's a fully solar-powered barge that operates much like Baltimore's trash wheels, just on a larger scale. Sitting at the mouth of a river, it funnels trash onto a conveyor belt, and automatically distributes the waste across six giant dumpsters.But since this giant interceptor doesn't fit in smaller rivers, the team developed another solution, a standalone floating barrier to capture the waste, and a small, mobile conveyer belt that scoops up the trash and transports it to a dumpster onshore. This system is currently deployed in Kingston Harbour, Jamaica, where Slat says the rivers are too narrow for the Interceptor Original. And for the most severely trash-choked rivers, there's the Trashfence. The concept is simple. A 26-foot high steel fence is anchored to the bed of the river and stops the flow of trash during a big storm. Once the water level recedes, excavators remove the waste. But the onslaught of trash in one of the world's most polluted rivers in Guatemala proved too intense for version 1.0. "The force of the trash was so high that the trash fence failed, unfortunately," Slat said. "So we're now working on a version two that will hopefully be ready for the next rainy season."Overall, eight Ocean Cleanup interceptors are currently installed in Indonesia, Malaysia, Vietnam, the Dominican Republic and Jamaica. Slat expects about 20 will be installed by next year, including one in Los Angeles. AlphaMERSIndia-based company AlphaMERS makes another version of a river barrier. With 34 installations in eight different cities, this barrier is relatively low-tech and low-cost. It's much smaller than the Ocean Cleanup's Trash Fence, and not designed for the same extreme trash flow, but it's still pretty heavy duty. Made of stainless steel mesh, the AlphaMERS fence floats a couple feet above the water, and 15 inches below.
Cleaning up the world's plastic-choked rivers.