Ocean Cleanup founder, Boyan Slat, stood on the stage with the air of someone who had something important to say.
The 22-year-old engineer, entrepreneur, inventor, public speaker extraordinaire (he says he doesn’t like speaking in public but he’s still rather good at it) and all-round genius was about to tell a crowd of well-wishers and supporters, gathered in a business park in Utrecht in the Netherlands, about the latest phase of his project to clean up the great Pacific garbage patch.
That’s a collection of marine debris, containing a large amount of plastic waste, some of it many decades old, in the Pacific Ocean, between the Californian coast and Hawaii. The patch is already twice the size of the UK, and the UN Environment Programme says it is growing so fast it’s becoming visible from space.
The debris gathers in that part of the ocean because it gets trapped by the currents in the North Pacific gyre, where the warmer waters of the South Pacific meet cooler Arctic waters.
The gyre is one of five large systems of circulating ocean currents around the world. The Indian and Atlantic Oceans have their own garbage patches, as do shipping lanes in other seas. A recent study found that the Arctic Ocean contains more than 300 billion bits of floating plastic. Worldwide, there are more than five trillion plastic pieces in the oceans, according to a 2014 study by 5 Gyres, a non-profit advocacy group.
Slat’s audience at the Werkspoorkathedraal already knew that there’s a lot of plastic in the oceans. And that this is bad for marine life, for people who eat the fish that eat that plastic, and for the ocean itself. Those at the gathering also knew that for the past four years Ocean Cleanup has been developing the technology it hopes will do something about it.
Slat first had the idea of developing his gigantic V-shaped boom when he was at school. In 2012, aged 17, he spoke about cleaning up the oceans at a TEDx event, crowdfunded the idea, quit his aerospace engineering degree and set up the Ocean Cleanup Foundation. Now it has 60 employees and has since raised $31.5m in donations.
(Credit: The Ocean Cleanup)
V for very determined
Slat envisaged a 100m boom that would use wind, waves and currents to push floating rubbish into screens that extend from the floating barriers. The structure would act as a filter, positioned against the prevailing current.
The V shape was designed to concentrate the accumulated plastic at the centre of the structure where it could be periodically collected and sorted on moored platforms and picked up by boat every six months.
Slat had said many times that once this technology was in the water it would reduce the Pacific garbage patch by 42% within 10 years. Everyone gathered at the old factory hall in Utrecht that these days is used predominantly for business events knew all about this promise.
Some of those present, particularly the Dutch and German media, would also have known that last year, when Ocean Cleanup first tested the prototype of its barrier in the North Sea, the structure lasted only two months before it had to be removed, unable to withstand the forces unleashed by the waters and the weather.
Soon after the structure was removed came a collective ‘told you so’ from critics, mainly experts in oceanography or environmental science. The structure was not strong enough, some said. And it didn’t actually collect any plastic while it was in the North Sea. Wouldn’t such a structure placed in the Pacific garbage patch harm wildlife, by attracting animals to the toxic areas? What about micro plastics and the plastic on the ocean floor? Was the structure worth two million euros? Surely there were better ways of dealing with ocean pollution?
Second time lucky?
Slat, however, thinks that the failure of the first Ocean Cleanup prototype was a good thing, as it enabled him to learn lessons and find solutions to problems at an early stage.
“It’s intuitive engineering,” he told the gathering in Utrecht. “With a new machine like this, you test, you learn, you sometimes fail, and then you repeat until you make it work.”
This was all very good, but it was old news. People had come to the Werkspoorkathedraal to hear Slat say something new, something big.
Slat knew this and, like all good public speakers, kept the audience waiting for what they wanted. But not for too long.
To get over the problems encountered last year, Slat announced that he would make a barrier that acted like the plastic in the ocean, whatever that meant.
The plan now, he continued, was to try to use natural ocean currents to clean up the plastic. The previous problem, he said, had been caused by trying to anchor the barrier to the ocean floor. This exposed the structure to the full force of the ocean and the impact of the weather.
Slat wondered out loud if this problem would go away if the barrier were fixed to a heavy floating object, in deeper water.
He answered his own question. “At the ocean’s surface the water speed is relatively fast, about 18cm per second,” he said. “However, only 100m deeper, the speed drops to around 3cm per second.”
Waves of doubt
This, Slat added, meant that the structure would have to withstand only 1/25th of the force that went through a system fixed to the sea bed. With a floating barrier, it was no longer necessary to understand the sea bed composition, whether it’s rock or clay. Slat could hardly lift a segment of the thick, heavy mooring line used for the fixed structure. The new mooring line was thin enough to fit in his pocket.
“Ocean currents aren’t constantly coming from one direction,” Slat said. “We want the system to be free to rotate and move in the direction the plastic is coming from. The forces moving the plastic around, the waves and currents, will be the same forces that move the clean-up system around. As long as the clean-up system moves slower than the plastic, we will collect plastic,” he said. “This,” he continued, to rapturous applause, “is what I meant by ‘acting like the plastic’.”
Of course, the barrier would have to be a lot smaller than the original model. But that, apparently, was a good thing too. On the big screen behind their chief executive, the Ocean Cleanup IT team ran a computer model showing everyone how a number of clean-up systems might work, together, in the ocean.
Because the barriers moved with the plastic, Slat explained, the concentration of plastics around the clean-up systems was much higher, five to ten times higher, than if the system was fixed to the ocean floor. Cue more applause and a bit of open-mouthed astonishment. But Slat wasn’t done, yet.
The original plan, with the single fixed barrier, he said, was to start in 2020 and clean up 42% of the plastic in the Pacific garbage patch within 10 years.
Ocean Cleanup founder Boyan Slat (Credit: The Ocean Cleanup)
A new promise
Unfortunately, Slat announced, Ocean Cleanup wouldn’t be able to keep that promise. Such a dramatic change in the design would have some repercussions on the planning. He paused and the audience shrugged. Of course there would be a delay. It was a shame, but understandable.
But Slat had a glint in his eye. Like all the best orators, he was deliberately letting his audience down, but only for a few seconds, all the time knowing full well that he had the real punchline up his sleeve.
Ocean Cleanup was unable to keep the original promise, yes. But Slat could make a new promise. “With this new technology,” he announced, “we will remove 50% of the plastic from the great Pacific garbage patch within five years.” Slat then added that he planned to put the first barrier into the Pacific Ocean, not in 2020, but in 2018.
And, just to show that he meant it, the screen at the back of the stage parted, revealing two of the large floating pipe anchors that Slat said are being made in California right now.
Cue more applause, cheering and collective adulation. Slat stood humbly taking it all in, like a performer after a particularly successful opening night. Soon he was joined by the rest of his team, all, except the suited executives, in sky-blue Ocean Cleanup T-shirts. For a few moments, Slat was like a rock star, surrounded by his roadies and sound crew, taking the final bow. But Ocean Cleanup’s critics are still unimpressed.
Erik van Sebille, an oceanographer from Imperial College London, thinks that resources should be targeted at preventing rubbish from entering the ocean, not cleaning up what is already there. He believes that trash does more harm to marine life nearer to the coasts than in the middle of the ocean, so clean-up efforts should be focused nearer land. He points out that the world will be producing as much plastic in the next five years as it did in the whole of the 20th century.
Richard Thompson, a marine biologist from Plymouth University, thinks that resources should be put into developing better waste management and recycling systems, particularly in those countries that are putting most of the rubbish into the oceans.
Setting sail
“Plastic is going into the oceans faster than we can ever take it out, and taking it out costs a lot of money,” he says. “Only when these systems are in place should we worry about cleaning up what’s already there.”
Slat has heard this sort of thing before, however, and has a ready-made response for the naysayers.
“Four years ago, when I founded the Ocean Cleanup, everyone told me that there was no way of cleaning up what was already out there,” he says. “If the oceans will be polluted forever and the best we can do is not make it worse, that’s a very uninspiring message.”
Slat also believes that, now Ocean Cleanup has shown that there’s a way to make the ocean clean again, that will motivate people to work on the prevention side as well.
Judging by the looks on people’s faces around the Werkspoorkathedraal, people there believed this, too. But that was to be expected. Slat was, after all, talking to the converted.
Will Slat’s words turn out to be those of the intrepid innovator, persistent and unyielding in the face of adversity and the harsh comments of the naysayers? Or is he simply pig-headed and, as some say, showing a dangerous and expensive unwillingness to look facts in the face?
We should find out more when Ocean Cleanup puts its first barrier in the Pacific Ocean, in just over a year’s time.
(Credit: The Ocean Cleanup)
The research: how much plastic is in the oceans?
- 8m tonnes of plastic entered the world’s oceans in 2010. China was responsible for 28% of it.
- There’ll be more plastic in the ocean than fish by 2050. That’s one refuse truck worth of plastic dumped in the sea every minute, expected to increase to two by 2030 and four per minute by 2050.
- Plastic production is expected to quadruple by mid-century. Only 5% of the world’s plastic is recycled.
- 82% of the plastics found in ocean samples taken by the Mississippi-Alabama Sea Grant Consortium were made up of micro-fibres.
- Each cycle of a washing machine could release more than 700,000 microscopic plastic fibres into the environment.
- Plastic waste on beaches can be underestimated by up to 80%, says the Institute of Marine and Antarctic Studies at the University of Tasmania.
- There was a 43% increase in the number of plastic bottles washed up on UK shores in 2014-15.
Content published by Professional Engineering does not necessarily reflect the views of the Institution of Mechanical Engineers