Environment
Why the plastic scooper was doomed to fail
Experts warned that a floating rubbish collector wouldn’t work in the ocean
The remarkable journey of a multimillion-dollar plan to remove plastic from the Pacific began with a teenager’s TEDx talk.
In 2012, 18-year-old Boyan Slat proposed an invention to collect garbage from the ocean surface. His talk went viral. Slat dropped out of Delft University of Technology and founded the Ocean Cleanup, a Dutch nonprofit organisation trying to build a flotilla of sea-sweepers.
By 2017, the Ocean Cleanup had raised US$31.5 million, which included contributions from billionaire venture capitalist Peter Thiel and philanthropists Marc Benioff and Lynne Benioff.
Rougher water lay ahead. The organisation’s first collector, a 610m buoy-and-skirt invention nicknamed Wilson, broke in two. On December 29, the Ocean Cleanup discovered that a 18m section had snapped free. Worse, during its initial four months at sea, Wilson failed to collect any rubbish in a rubbish-rich region known as the Great Pacific Garbage Patch.
Scientists unaffiliated with the project are sceptical that this system, or future iterations, will work as intended.
Kim Martini, an oceanographer and science communicator, and Miriam Goldstein, director of ocean policy at the Centre for American Progress, independently reviewed the Ocean Cleanup’s feasibility study in 2014. “When the feasibility study came out, the press was really excited about this,” Martini said. “But a lot of scientists had been saying, ‘Well, you know, this is really hard and probably not going to happen’.”
Since the 2014 review, the buoy-and-skirt design changed, becoming smaller and omitting a deep-sea anchor system. But Martini and Goldstein said their assessment remains the same: The Ocean Cleanup’s goals are laudable. Its invention is not feasible.
This month, Clark Richards, a physical oceanographer at the Bedford Institute of Oceanography in Nova Scotia, pointed out the possible physics flaws in Wilson’s design.
By 2050, oceanic plastic will outweigh the collective bulk of the world’s marine fish, the World Economic Forum recently predicted.
The Ocean Cleanup likens its invention to an artificial coastline. Beneath the long buoy is a skirt that descends 3m below the surface. The system, propelled by wind and wave energy, is supposed to outpace the plastic particles. In theory, the skirt should corral plastic, like a broom, into a contained area where ships can easily scoop up the trash.
Richards was not shocked that a large, first-of-its-kind structure broke after a few months at sea. Given the harshness of the ocean environment, “we tend to build things as small and minimal as possible”.
The Ocean Cleanup may be relying on simplified physics that do not account for small-scale currents, Richards wrote on his blog on January 6.
A complex dance of waves, wind and current plays out at the ocean’s surface, he said. That dance may not propel the system as fast as it needs to go.
“I am sceptical, with their current design, they can make fixes — by that I mean small or incremental things — that will change the reality of the ocean environment that they are trying to harness.”
Jan van Ewijk, a representative for the Ocean Cleanup, said: “Our working hypothesis is that material fatigue, caused by about 1.5 million load cycles, combined with a local stress concentration” led to a fracture. The organisation aims to deploy 60 buoys in the coming years that it claims could shrink the Great Pacific Garbage Patch by 90 per cent by 2040. “We are not ending the programme. Wilson will be repaired, modified and brought back to the [patch] as soon as possible.”
Although Wilson was too sluggish in its first test, “most aspects of concept have been confirmed,” including the ability to intercept plastic, Slat tweeted on December 11. “It’s just not moving fast enough yet. This is fixable.”
Goldstein argues for stopping waste sooner — preventing rubbish from leaving the coasts — before devoting resources to the plastic waste far from shore.
“Legislation is really the way to go,” Martini said, to “make people responsible and companies responsible for the amount of plastic they’re producing.”.