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Cleaning the garbage problem

Julian Ryall Tokyo
May 16, 2017

In a bid to clean up the islands of garbage streaming across the world's oceans, a new system designed to collect millions of tons of plastic is to be launched in the Pacific by the end of the year. Julian Ryall reports.


For the last six years, Boyan Slat has been working toward making a dream into reality. Now, at least two years ahead of his initial schedule, the Dutch entrepreneur is preparing to launch a revolutionary system that is designed to clean the world's oceans of discarded plastic.

With more than five trillion pieces of plastic littering the seas - and increasingly breaking down and entering the food chain - Slat agrees that it is a momentous undertaking. But he is confident that enhancements to the design of the equipment used by his company, The Ocean Cleanup, will enable the system to remove 50 percent of the Great Pacific Garbage Patch in just five years.

To give some idea of the scale of the task, estimates put the debris field located between the coast of California and the Hawaiian Islands at between 700,000 square kilometers and 15 million square kilometers. Similar patches of waste blight other oceans, but the one in the Pacific is the most expansive.

And every year, a further 8 million tons of plastic is dumped into the world's oceans, Slat points out, "which is the equivalent volume of two Empire State Buildings every week."

Oceans in crisis

Slat was first confronted by the crisis facing the planet's seas on a summer holiday to Greece at the age of 16. Instead of a clear blue sea inhabited by multi-colored fish, he discovered shards of plastic in the waves and on the sand.

Two years later, at the age of 18, he dropped out of a degree in aerospace engineering after just six months to set up The Ocean Cleanup. Based in the Dutch city of Delft, the foundation set about testing Slat's proposal for a startlingly simple solution to the problem of plastic pollution.

Efforts to date to cleanse the oceans of plastic have been based on ships crisscrossing the polluted areas and collecting debris as they go. According to simulations, that approach to the problem will take 79,000 years and an undeterminable amount of money.

Slat's answer is the Ocean Cleanup Array, a boom that extends for many kilometers on the surface of the ocean and takes advantage of currents and winds that bring plastic debris into the arms. The plastic is then funneled to collecting points on the boom, where it is gathered and stored until a large amount has been collected and can be shipped away for recycling.

The Ocean Cleanup Pressebild
The Ocean Cleanup wants to use a boom that extends for many kilometers on the surface of the ocean and takes advantage of currents and winds that bring plastic debris into the armsImage: Erwin Zwart/The Ocean Cleanup
The Ocean Cleanup Pressebild
The plastic is then funneled to collecting points on the boom, where it is gathered and stored until a large amount has been collected and can be shipped away for recyclingImage: Erwin Zwart/The Ocean Cleanup

Overcoming challenges

The foundation has faced huge obstacles in the years since the project began - including whether to attach the array to the seabed or to let it drift, with collection efficiency, maritime law, the quality and recyclability of the plastic recovered - but Slat is confident that he will be ready to start extracting plastic from the Pacific within the next 12 months.

Unveiling the latest refinement to the technology in Utrecht on May 11, Slat announced that the first trial system would be installed off the west coast of the United States by the end of 2017 and a full-scale device would be deployed amid the Great Pacific Garbage Patch in the first half of 2018 - two years ahead of schedule.

"The clean-up of the world's oceans is just around the corner," said Slat, with four 12-meter sea anchors for the system towering over him. "Due to our attitude of 'testing to learn' until the technology is proven, I am confident that - with our expert partners - we will succeed in our mission."

Speaking subsequently with DW, Slat said the design has moved away from a system tethered to the seabed and has instead made progress with a floating system that uses sea anchors to ensure that the floating booms move more slowly than the plastic.

And instead of one huge barrier - one design was for a boom 100 kilometers from tip to tip - the improved modular system consists of a "fleet" of smaller screens, he added.

Improving the system

"Besides the new funding we have been able to realize, we have also been able to make significant changes and improvements in the system," Slat said.

"It is in constant flux. We constantly test to 'poke holes' in the design, so there are constant detail changes happening to it.

"The biggest visible change is the switch from a system moored to the seabed to a free-floating system," he said. "We learned this has many advantages, including reduced cost, higher plastic capture efficiency, lower pressure on the barrier from wind, waves and current, as well as the ability to learn from the first system before launching a second one.

"We now believe we have designed a much more robust and effective system, based on the lessons of our study and tests," he underlined. "It will not be perfect yet, but it will be a good point to study the iterative process of testing and improving the system in the Pacific."

According to Slat, at least 100 species are threatened with extinction as a result of plastic pollution, while the United Nations has estimated that countries around the world spend $13 billion on cleaning beaches. More is lost in damage caused to the fishing and tourism industries.

Slat's project aims to be far more than a drop in the ocean when it comes to cleaning up our seas.

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