How companies are cleaning the world’s most polluted rivers

Every year, millions of tons of plastic waste are discharged into the ocean, most of it coming from around 1,000 hyper-polluting rivers. And with overall waste production set to increase by more than 75% by 2050, the problem is set to get worse.

Companies around the world have turned their attention to the river litter problem, building various barriers, fences and wheels that help contain and remove litter as it flows downstream.

Approaches range from solar-powered barges collecting waste to stainless steel fences and different rivers will require different methods.

Here’s how three companies, Clearwater Mills, The Ocean Cleanup, and AlphaMERS are addressing the problem.

Clearwater Mills Trash Wheels

Baltimore’s googly-eyed garbage wheels, the first of which debuted in 2014, are one of the original efforts to tackle river litter. Built by Clearwater Mills, company founder John Kellett was inspired to design wheels after years of seeing trash pour into the Baltimore Harbor after major 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 anthropomorphic wheels that have become minor social media celebrities in the city.

Baltimore’s Mr. Trash Wheel devours garbage and debris after a major storm.

Baltimore waterfront partnership

Here’s how they work: The containment arms are arranged in a V-shape across the river, with rubber skirts extending about two feet below the water’s surface. This captures waste floating downstream and channels it to the “mouth” of the rotating water wheel, which is powered by the river current and connected solar panels. The rotation of the wheel feeds a conveyor belt that lifts waste and debris from the river and deposits it in a bin. Connected cameras allow the team to monitor how full the bins are.

“And when that dumpster is full, we have another floating barge that we carry with an empty dumpster. Get the full one, slide the empty one, and keep picking up the trash,” Kellett said.

The four wheels collected a total of around 2,000 tons of garbage and debris. Sticks and leaves make up the bulk of this weight since plastic is so light, but the total haul includes around 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 plant.

Additional trash wheels are planned for Texas, California and even Panama, where the local Green Tide nonprofit has partnered with Clearwater Mills to build the family’s fifth wheel, called Wanda Díaz. The project is funded by the Benioff Ocean Initiative and the Coca-Cola Foundation, which together support a portfolio of river cleanup projects around the world.

Cleaning the ocean

Ocean Cleanup is arguably best known for its efforts to clean up the Great Pacific Garbage Patch, a feat young company founder Boyan Slat began pursuing in 2013 after a TED speech he gave on the subject is went viral. The company is now pursuing a dual goal as it has also built a number of river cleaning technologies.

“Our goal is to rid the oceans of plastic and the reason we look at rivers is because we believe it is the quickest and cheapest way to prevent more plastic from being emitted into the ocean,” Slat said.

The company’s first river cleaning device, called the Interceptor Original, was released in 2019. It’s a fully solar-powered barge that works much like Baltimore’s trash wheels, only on a larger scale. Located at the mouth of a river, it conveys the garbage onto a conveyor belt and automatically distributes the waste onto six giant bins.

Ocean Cleanup’s Interceptor Original at work on Rio Ozama in the Dominican Republic in summer 2020.

Cleaning the ocean

But because this giant interceptor doesn’t fit into smaller rivers, the team developed another solution, a self-contained floating barrier to catch waste and a small mobile conveyor belt that collects waste and transports it to a bin on the ground. This system is currently implemented in Kingston Harbor, Jamaica, where Slat says the rivers are too narrow for the Interceptor Original.

And for the rivers that are most severely choked with litter, there’s the Trashfence. The concept is simple. A 26-foot high steel fence is anchored to the river bed and blocks the flow of waste during a major storm. Once the water level recedes, the excavators remove the waste. But the onslaught of garbage on one of the world’s most polluted rivers in Guatemala proved too intense for version 1.0.

“The strength of the garbage was so high that the garbage fence failed, unfortunately,” Slat said. “So now we are working on a version two that hopefully is ready for the next rainy season.”

Eight Ocean Cleanup interceptors are currently installed in Indonesia, Malaysia, Vietnam, the Dominican Republic and Jamaica. Slat expects around 20 to be installed within the next year, including one in Los Angeles.


AlphaMERS, based in India, builds another version of a simple river barrier and has 34 installations in eight different cities across the country. It’s much smaller than Ocean Cleanup’s Trashfence and isn’t designed for the same extreme waste stream, but it’s still pretty heavy. Made from stainless steel mesh, the AlphaMERS Fence floats a couple of feet above the water and plunges approximately 16 inches below.

“The hydrodynamics and hydrostatics of this are very simple but excellent for the job,” said AlphaMERS founder DC Sekhar. “And it’s made very strong, very strong with steel chains that hold it on both sides. So it’s able to withstand the monsoon flows right after the rain.”

Sekhar says his floating fence excels at stopping trash in rivers with fast currents, while projects that rely on a boom and skirt may fail when the currents rise, as water will instead flow past the barrier, carrying with it the garbage.

The AlphaMERS floating barrier captures waste as it flows downstream


Eight floating barriers were deployed at various points along the Cooum River in Chennai in 2017. Sekhar claims to have captured around 2,400 tons of plastic in their first year of operation.

The barriers are angled to direct waste to the river bank, where excavators have traditionally collected waste from rivers. AlphaMERS used conveyor belts instead, just like Clearwater Mills and The Ocean Cleanup.

“One end is floating, one end is on the ground,” Sekhar said of the conveyor belts. “And now it runs on electricity, with portable generators. But very soon we will make it run on the flow of river water.”

The future of waste

These organizations share the same goal of removing as much waste from our lives as possible, but they also understand that river cleaning systems are not the ultimate solution.

One of the things we look forward to is when the garbage wheels are no longer needed, “Kellett said.” When we address the problem upstream to the extent that no waste enters our waterway and we don’t need to a garbage wheel “.

Getting there will be difficult and will depend on a combination of better waste infrastructure, more sustainable packaging, less consumption and public awareness of proper disposal.

Middle-income countries such as the Philippines, India and Malaysia contribute the most to ocean litter. The population has enough money to buy a lot of packaged goods, but the waste collection infrastructure is lagging behind.

Sandy Watemberg, executive director of the non-profit organization Marea Verde, is thrilled that her organization has brought the Wanda Díaz garbage wheel to Panama and is optimistic about its future performance.

So we are very confident that this will be a great success for our country, “Watemberg said. However, he knows that real change will take much longer.

“Having these technologies and this kind of projects is not the solution. We have to change our habits. We have to look for long-term solutions that allow us to have a cleaner and healthier environment because these types of projects help us to create awareness and help us to mitigate in the short and medium term. But in the end, this is not something sustainable. We can’t have thousands of projects like this running forever. “


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