Boyan Slat’s plastic waste Ocean Cleanup commences, not without criticism reports, 11th September 2018: A high-profile and controversial effort to collect and haul away plastic trash in the ocean is finally going to sea.

A massive tugboat left San Francisco Bay this weekend, pulling a long sinuous boom constructed by The Ocean Cleanup, a non-profit organisation based in Rotterdam, the Netherlands.

The device, which is intended to catch plastic trash floating at the surface, will be tested for 2 weeks about 400 kilometres offshore. If it does well, the boom will be towed to a concentration of floating trash about 2200 kilometres from California.

Although the original design called for a few trash collectors each with a 200-kilometre span, revised plans called for many smaller collectors with 1-kilometre-long booms. The current system has been scaled down further, to 600 metres in length.

The Ocean Cleanup hopes to make its first pickup run in 6 months, shipping the trash back to shore and converting it into promotional objects to help cover costs. As Science reported below on 11th May 2017, critics are sceptical of the project, which some see as well-intentioned but misguided.

An experimental plastic trash collector is towed out of San Francisco Bay on 8th September.
Photo: The Ocean Cleanup.

In an undeniably ambitious vision, Boyan Slat, a charismatic 22-year-old drop-out inventor, plans to clean up plastic trash circulating in the North Pacific Gyregyre A circular pattern of currents in an ocean by launching a fleet of floating trash collectors. Ocean currents would propel floating plastic trash into curved floating booms, which would funnel trash toward a central tank, to be collected monthly by ships.

“We let the plastic come to us,” he says. The group hopes to eventually finance the operation by recycling the plastic and selling it as a branded product or raw material. Slat already has a pain of of sunglasses made from recycled Pacific plastic.

Skeptics say the idea doesn’t make much sense and that collecting trash closer to shore would be more cost effective. “Focusing clean-up at those gyresgyre A circular pattern of currents in an ocean, in the opinion of most of the scientific community, is a waste of effort,” says marine biologist Jan van Franeker of Wageningen Marine Research in the Netherlands. “It’s a lot of money to reduce something that disappears in 10 to 20 years, if you stop the input.” His research on seabirds showed a 75% decline of ingested plastic over 2 decades after reductions in industrial plastic entering the North Sea. Critics also worry that the high-tech clean-up project could distract from less glamorous efforts to lessen the use of plastic.

Slat’s 4-year-old organisation, The Ocean Cleanup, based in Delft, the Netherlands, is well on its way to launching its first unit. At an event in the Werkspoorkathedraal — an industrial meeting hall in Utrecht, the Netherlands — Slat unveiled a new design that he says will allow The Ocean Cleanup to deploy its first collector in 2018, 2 years earlier than planned. It will also collect trash at twice the rate of earlier designs, he predict

Slat says he first experienced ocean plastic when he was 16. While diving in Greece, he recalls, he saw more plastic bags than fish. He designed a high school science project for cleaning up marine trash, and says he’s always been passionate about technology. “The act of creation, making something a reality, is one of the most fulfilling things you can do.”

After a half-year of studying aerospace engineering (model rocketry was another early passion), Slat left university to found The Ocean Cleanup in 2013. Since then, and with the help of a TEDx Talk that has received 2.5 million views, The Ocean Cleanup has raised $31.5 million in donations — two-thirds of it since November 2016, with large amounts coming from silicon valley investor Peter Thiel, the chemical company Royal DSM, and other donors.

The Ocean Cleanup has about 65 engineers and other staff. While designing the collector, Slat’s team has also been studying plastic in the North Pacific. Most research vessels use 1-metre-wide trawls to sample plastic debris. In 2015, The Ocean Cleanup organised an expedition of some 30 ships, including a decommissioned National Oceanic and Atmospheric Administration research vessel, to measure larger pieces of debris. Last year, they also flew over the area to measure amounts of even bigger trash, including lost or discarded fishing gear called ghost nets. They plan to publish their findings this year.

In June 2016, the group tested a 100-metre prototype collector for structural integrity, placing it 16 kilometres into the North Sea. After 2 months the shackles connecting the booms to the mooring had begun to fail. Although the prototype experienced weather rougher than that typical of the Pacific, the test highlighted the long-standing challenge of how to secure the collectors to the seabed in water some 5 kilometres deep.

In a shift, engineers have come up with a new design. The approach is to use weights suspended a few hundred metres below the surface, where, according to the organisation’s ocean circulation models, the currents are about one-fifth the surface speed. The weights consist of 12-metre-tall metal towers, shaped like a plus sign in cross section, that will drag in these slower currents. Because the surface water moves faster, plastic debris will collect on the drifting booms.

The organisation also announced today it was downscaling the overall design. Instead of a few units each with two 100-kilometre-long arms, they will build multiple smaller collectors that are 1 kilometre long. This smaller scale should cut the per-unit cost to a few million dollars, Slat says, and also advance the production schedule by about 2 years, allowing deployment of the first unit in early 2018. Initial calculations suggested a moored design would collect about 40% of the plastic in the North Pacific Gyre within 10 years. The new design should be able to collect trash faster — by drifting into the denser accumulations of plastic — and remove half of the plastic within 5 years, once 50 units are at work.

Erik van Sebille, a physical oceanographer at Utrecht University, Netherlands, attended the event and liked what he saw. Two years ago, he says, Ocean Cleanup seemed like a group of single-minded engineers out to save the world. “A lot of scientists thought they were stubborn,” he says. “Yesterday they showed that there are not afraid to change their approach. The radical rethink, ditching the mooring — I think that’s great. And they’ve become more scientifically aware.” From an oceanographic perspective he says the new design “makes sense in the first order,” but he would need to see more details before being convinced that it will work as intended.

So far, critics haven’t been impressed, listing technical limitations and concerns such as harm to marine life. “It’s not the best solution,” says Marcus Eriksen of the ocean non-profit The 5 Gyres Institute, based in Los Angeles, California. “In fact, it’s a distraction from the work going on upstream.” Most environmental groups working on ocean pollution focus on reducing the amount of plastic that enters the ocean, and, ultimately, what Eriksen calls “the heavy lift of ending the one-time, throwaway culture.” Another issue is that researchers suspect much of the plastic that enters the ocean sinks to the sea floor, where it is inaccessible to floating trash-catching devices.

The open ocean may not be the best place to locate trash collectors. Computer simulations, published last year in Environmental Research Letters, suggested that collectors located near China and Indonesia would be more than twice as efficient at capturing microplastic — and collect fewer planktonplankton Plankton is a generic term for a wide variety of the smallest yet most important organisms form that drift in our oceans. They can exist in larger forms of more than 20cm as the larval forms of jellyfish, squid, starfish, sea urchins, etc. and can be algae, bacterial or even viral down to as small as 0.2µm. They are nutrient and light dependent, and form the essential foodchain baseline for larger dependent aquatic lifeforms. Fish species rely on the density and distribution of zooplankton to coincide with first-feeding larvae for good survival of their larvae, which can otherwise starve. Man-made impacts such as dredging, dams on rivers, waste dumping, etc can severely affect zooplankton density and distribution, which can in turn strongly affect larval survival and thus breeding success and stock strength of fish species and the entire ecosystem. They also form the essential basis of CO2 take up in our seas ecosystem, hence Global Warming. — than ones located in the North Pacific. In streams and rivers, floating collectors can significantly reduce the amount of trash entering the ocean.

Slat replies that there is not an either-or solution. “We need to do both,” he says. “We need to intercept plastic before it becomes ocean plastic. And we need to clean up what is out there.” Eriksen says that plastic on the high seas is mostly lost or discarded fishing gear. Fishermen could be paid or encouraged to collect it, which he says has worked reasonably well in the North Sea. The rest will eventually break down.


Source:, 11th September 2018.  For the full details, see


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