30 Nov 2018 Story Oceans & seas

Pioneering sea-cleaning system hits snag but Ocean Cleanup team vows to fix problem

After four weeks in the Great Pacific Garbage Patch, the first results are in for Dutch inventor Boyan Slat’s hugely ambitious attempt to clean up the enormous marine dump with a giant U-shaped floater nicknamed Wilson. It’s a mixed picture.

The Ocean Cleanup team, which runs the passive drifting system, says Wilson, or System 001, has started to scoop up some of the estimated 1.8 trillion pieces of plastic in the Garbage Patch but some of the plastic is drifting out again. This is a problem because the aim was for a ship to regularly collect the plastic and take it back to shore for recycling.

“It has been four weeks since we deployed System 001 in the Great Pacific Garbage Patch. In this time, we have observed that plastic is exiting the system once it is collected so we are currently working on causes and solutions to remedy this,” Slat wrote on the team’s website.

“Because this is our beta system, and this is the first deployment of any ocean cleanup system, we have been preparing ourselves for surprises.”

One possible solution may be to expand the U-shape floater to enable it to move faster and hold onto the plastic.

Wilson comprises a 600-metre-long floater that sits on the surface of the water and a tapered three-metre-deep screen that hangs down and stops plastic from floating away. Perhaps best described as an artificial coastline, it uses the waves, currents and winds to curve into a U-shape and trap the plastic in its centre.

The system is the brainchild of Slat, who was named a UN Environment Champion of the Earth in 2014. He set up The Ocean Cleanup five years ago in his hometown of Delft.

One possible reason for the plastic failing to stay inside the floater could be that Wilson is moving too slowly—to function effectively it needs to be continuously travelling faster than the plastic. Another hypothesis is that the force of the wind could be making both ends of the floater vibrate, counteracting the force of the wind, slowing the system and repelling plastic.

One fix could lie in widening the span of the U-shaped floater by 60-70 metres.

“The focus is currently on extending the span of the floater as the first modification, for which we have all the tools available on board the (support) vessel. While we are busy implementing this first solution, our team is continuing to analyze more data and test alternative solutions until the system is fully operational,” the team said.

The span will be extended by gradually lengthening the closing lines which keep the system in a U-shape. The team will have to work slowly to avoid adversely affecting the system’s ability to rapidly pivot when the wind changes.

If this solution does not work, the team will test alternative fixes to fulfil their mission of ridding the seas of a toxic tide of plastic that endangers marine wildlife.

Every year, at least eight million tonnes of plastic leak into our oceans—the equivalent of dumping a garbage truck of plastic every minute. In 2017, UN Environment launched its Clean Seas campaign to inspire governments, businesses and people to take action. Solutions have ranged from charges levied on plastic bags, bans on straws and other disposable items, and investment in recycling facilities and alternatives to plastic.

Some critics have said The Ocean Cleanup risks undermining these efforts because consumers may decide that there is no need to change their behaviour if plastic can be cleaned from the seas.

Others raised fears that the system could harm marine wildlife. The Ocean Cleanup team has said Wilson moves very slowly so that creatures have time to swim away, and the hanging screen is impenetrable, meaning that the current will flow underneath, guiding living organisms.  

In its latest update, the team said no interactions with marine life had been observed.

Deployed from San Francisco in early September, the system underwent a series of trials in the open sea before being towed to the garbage patch, a gigantic swell of rubbish twice the size of France that lies 1,200 nautical miles offshore between Hawaii and the West Coast of the United States.

Since its installation, the system’s behaviour has been monitored by a support vessel, GPS drifters and drones. It is also equipped with solar powered lights, anti-collision systems, cameras, sensors and satellite antenna allowing it to transmit data.

Wilson has fervent supporters and ardent detractors. Before the mission began, The Ocean Cleanup asked marine environmental consulting firm CSA Ocean Sciences Inc. to evaluate its project.

In its assessment, CSA said there was a significant risk of harm if the system went astray but that the potential benefit outweighed the risk. However, others remained unconvinced.

In June, marine biologist David Shiffman sought the opinion of 15 ocean plastic experts and found that none supported the project unreservedly. They feared wildlife would be harmed and also worried that the multimillion-dollar project would divert attention and resources from other ways to deal with our plastic addiction.

The Ocean Cleanup team argues that while other solutions must be pursued, the plastic already in the ocean must also be removed. Despite the initial setback, they believe they will succeed.

“System 001 is a beta system and we expected the unexpected,” the team said. “A real-life system is always different than a model or a simulation, so we anticipated learning opportunities such as these. We are positive we will learn a lot from our planned modifications.”


Ahead of the United Nations Environment Assembly next March, UN Environment is urging people to Think Beyond and Live Within. Join the debate on social media using #SolveDifferent to share your stories and see what others are doing to ensure a sustainable future for our planet.