Saturday, January 22

Meet Mr Trash Wheel, and the other nifty tools that eat river plastic | Pollution


The Great Bubble Barrier is just that: a wall of bubbles. It gurgles through the water on a diagonal screen, pushing the plastic to the side while allowing fish and other wildlife to pass unharmed.

The technology, created by a Dutch company and already being used in Amsterdam, is being tested on the Douro River in Porto, Portugal, as part of the EU-backed program. Swirl (removal and sustainable management of marine litter).

It is the latest in a series of new technologies designed to find sustainable ways to remove and treat river waste before it reaches the sea.

Plastic can be spread by natural disasters, such as a tsunami, which can push invasive species and debris to the other side of the world. But rivers carry a much more regular supply of plastic to the oceans. Research in 2017 found that 10 river systems carry 90% of all plastic that ends up in the world’s oceans (two in Africa, the Nile and Niger, and the other eight in Asia: the Ganges, the Indus, the Yellow, the Yangtze, Haihe, Pearl, Mekong and Amur).

A man in the bow of a small boat paddles through a floating mat of rubbish that covers the surface of a wide river
A man paddles along the Citarum River in West Java, Indonesia, one of the most polluted rivers in the world. In 2018, it was estimated that 20,000 tons of garbage and 350,000 tons of wastewater were dumped into it every day. Photograph: Andrea Carrubba / The Guardian

Molly Morse, UC Santa Barbara Benioff Ocean Initiative Scientist and Global Project Leader Clean Currents Coalition, says: “In some cases, communities do not have access to adequate waste collection services and must resort to what might seem like the only alternative: dumping the garbage directly into the river to be carried away.

“In other cases, plastic garbage on land is moved by rain or wind into a river, where […] the plastic can reach the ocean ”.

An estimate 0.8 million to 2.7 million tons of plastic they are carried by rivers to the ocean every year. That’s the equivalent of 66,000 to 225,000 double-decker buses.

Without barriers, river currents carry plastic directly into the sea, where it becomes much more difficult to tackle: plastic often floats long distances, can harbor invasive species, and becomes part of the larger plastisphere, such as the concentration of waste transported by sea in the Greater Pacific. Garbage stain.

This is why some scientists call for greater efforts to prevent plastic from reaching rivers in the first place. A 2020 study found that a “significant reduction” of plastic in the ocean could only be achieved by preventing it from reaching the sea, or by a combination of river barriers and other cleaning devices.

Cue inventors, who have developed a variety of river barriers and collection devices to trap and remove river plastic, from simple nets and barriers to conveyor belts and robots.

Mr trash wheelOfficially known as the Inner Harbor Water Wheel, it is a solar-powered, current-powered conveyor belt system launched in 2014 in the American city of Baltimore. Long feathers with submerged skirts funnel waste to a central hub, where autonomous rakes collect it on a conveyor belt that deposits it onto a barge, with more than 17 tons collected in one day.

Once full, the barge takes the rubbish away for incineration at a power plant, although it is hoped that eventually the collected waste can be sorted and recycled. Now there is a whole family of Trash Wheels in Baltimore, being the latest addition Gwynnda, the Good Wheel of the West.

graphic explaining how a bubble barrier can divert plastic waste but let wildlife pass

Or there’s the Interceptor, a solar-powered floating device developed by the nonprofit organization Cleaning the ocean, heralded as the “world’s first scalable solution” for removing plastic from the oceans. Similar to but larger than the garbage wheel, it has barriers that guide garbage to a conveyor belt, where a shuttle distributes it among five garbage containers on board.

Another design, the Azure The barrier, developed by UK-based startup Ichthion to operate on any river, can remove up to 80 tonnes of plastic a day using durable tidal-sensitive barriers that direct plastic to extraction points along the Bank. The plastic is processed into flakes for recycling.

Other higher-tech inventions include the WasteShark, an electronically controlled “aquadrone” that takes advantage of plastic, up to 350 kg at a time. Using algorithms from the German Research Center for Artificial Intelligence, WasteShark autonomously moves around and back to its docking station, where up to five of the catamaran-shaped vessels can deposit the collected plastic and recharge. The design, developed by a Dutch startup, RanMarine, will be showcased at CES 2022 in Las Vegas this month.

A small catamaran-shaped drone that moves across the surface of a canal
The WasteShark aquadrone uses algorithms to autonomously move and return to its docking station, where it deposits collected plastic and recharges. Photography: Brochure

While the cost of implementing these technologies may be feasible for some cities and towns, and much more preferable to the cost of plastic pollution, which is estimated to reach $ 7.1 trillion (£ 5.25 trillion) by 2040 – There are many other factors to consider. These include, Morse says, “the physical characteristics of the river, the amount of debris, seasonal changes, ecology, energy sources, availability of labor, safety, boat traffic.” [and] money”.

Philip Ehrhorn, Co-Founder of Great Bubble Barrier, says: “One of the biggest challenges we face is the lack of regulation regarding plastic pollution in our waterways and therefore the lack of ownership and responsibility for the problem.

“The urgency of solving our problem of plastic pollution in rivers is due to forward-looking water authorities and governments, since plastic is not yet officially considered a water pollutant,” he says.

most of The 20 most polluting rivers in the world with plastic are in developing countries. But Ehrhorn adds: “Europe still has a big problem with plastic pollution, which should not be ignored or underestimated.”

EU laws were introduced in January last year to tackle the “wild west” of plastic waste being dumped in poorer countries; the UK is one of the worst offenders in Europe, exporting around 70% of its plastic. But the wildest west is on the other side of the Atlantic: the US is the world’s biggest plastic polluter, accounting for more than all the EU countries combined.

Municipal garbage collectors in boats try to clear a canal of floating debris and household waste
Plastic and other debris clogs Bangkok’s Ladprao Canal. Every day up to 10 tons of garbage is collected from the city’s canals. Photograph: Narong Sangnak / EPA

There is no one-size-fits-all solution, Morse says. Rivers vary enormously with regard to factors such as depth, width, flow, and seasonality. What might work for a massive river like the Mississippi in the United States, which flows year-round, probably won’t work for a smaller, more seasonal river like the Tijuana in Mexico. “

In Ecuador, Ichthion’s Azure prototype had problems on the Portoviejo river. The data had suggested that the depth of the river varied in the dry and wet seasons by two meters; actually, it fluctuated up to four meters in a few days.

It can also be difficult to get the support of the local population and permission for new infrastructure. For the Clean Currents Coalition, which works with eight teams around the world, simplicity works best.

“The most successful solutions have been the simplest technologies, such as barriers, barriers and traps, that are manufactured locally and require manual removal of captured waste,” says Morse. This can also create additional jobs.

An example of these is wild coastThe “gross boom” of Los Laureles Canyon, a tributary of the Tijuana River. The double-walled float runs along the river and allows the barrier to move with changing depth. A suspended steel mesh traps the plastic, which is taken for processing once the barrier is full. Reports from San Diego in California suggest that it has succeeded in reducing plastic downstream.

A barge moves along a river with the dome of a mosque in the background.
The Interceptor collects debris from the Klang River near the Malaysian capital, Kuala Lumpur. The device, developed by Ocean Cleanup, works with solar energy. Photograph: Mohd Rasfan / AFP / Getty

TerraCycleThe river traps, which are installed in some of Bangkok’s 1,600 polluted canals, trap up to 2.5 tonnes of waste a day, helping to recycle plastic rather than send it to landfill.

A German startup, Plastic fischer, has installed TrashBooms on channels in Indonesia, India and Vietnam. She advocates a low-cost, low-tech, local approach, using locally made mesh barriers and floats to catch trash.

Many environmentalists argue that these innovations address the symptoms, not the problem, and that the only real solution is to curb plastic production. But with Plastic manufacturing shipments are estimated to have increased by 2.2% last year by the Plastics Industry Association, this is not likely any time soon.

“If we are going to continue producing, consuming and disposing of plastics at or near our current rate, our ability to manage it must catch up, and quickly,” says Morse.


www.theguardian.com

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