Our oceans are teeming with garbage, but no collection of marine debris is quite as big as the Great Pacific Garbage Patch, a trash-filled vortex in the Pacific Ocean that's more than twice the size of Texas. The gyre is said to contain more than 1.8 trillion pieces of floating plastic, or the equivalent of 250 pieces of debris for every person on Earth.
When oceanographer Charles Moore discovered the vortex more than two decades ago, he estimated that it would take around 79,000 years and an entire fleet of ships to clean it up.
But at age 19, entrepreneur Boyan Slat outlined a plan to reduce the garbage patch by half in just five years.
Since 2013, Slat's organization, The Ocean Cleanup, has been developing a system to passively collect plastic from the garbage patch using the ocean's current. Their first tool — a floating, U-shaped array that captures plastic in its fold like a giant arm — launched in the Pacific Ocean in September 2018.
That device hit some obstacles: Shortly after the launch, The Ocean Cleanup discovered that the device was spilling the plastic it had collected. So for the last year, the organization has been tweaking the design to account for the flaw.
"I'm confident that, considering we created this problem, we should also be able to solve it," Slat told Business Insider.
This summer, the organization launched a new version of the device that's successfully capturing plastic in the garbage patch. The team is also researching the way plastic travels through the ocean to understand why certain items make it to the garbage patch, while others wind up on land or the ocean floor.
In a recent study, The Ocean Cleanup found that plastic objects that enter the ocean don't disintegrate right away, but can linger in the garbage patch for decades, if not centuries. Slat said the study confirms his strategy that ridding the ocean of plastic requires human intervention.
Here's how his system works.
The device acts like a giant arm that catches plastic
A recent study from The Ocean Cleanup found that plastic journeys through the water for a long time before reaching the Great Pacific Garbage Patch (if it ever makes it). Along the way, tides can pull the debris back toward shore, where it builds up along the coastline.
Slat's U-shaped system essentially creates a coastline in deep water. The most visible portion of the device is a 2,000-foot-long pipe made of high-density polyethylene, a type of plastic. The pipe is connected to a screen that extends about 10 feet below the surface, which is responsible for catching plastic debris.
In the first version of the device, the screen was attached to the bottom of the pipe like a skirt. But the team found that this configuration created too much stress at the point where the pipe and screen joined. In late 2018, a crack at the bottom of the pipe widened into a fracture, causing a 59-foot end-section to detach from the array.
To address this issue in the latest version, The Ocean Cleanup moved the screen in front of the pipe and connected it with slings. The designers also installed a cork line (similar to the ones that separate the lanes of a swimming pool) behind the screen to keep it taut.
To sweep the water for plastic, the system has to move, of course. But it's designed not to need any towing by a vessel. Instead, an underwater parachute anchor keeps the device moving slower than the ocean's current so that winds and waves push plastic inside the "U" to be caught by the screen. The Ocean Cleanup has realized that the device must travel at a consistent speed — either faster or slower than the plastic in the water — to effectively catch and keep the plastic.
"We now have plastic continuously floating into the cleanup system from the correct direction," Slat said.
However, Slat's team is still working to address another problem: Last month, the researchers found that plastic was spilling over the cork line, which sits about 10 centimeters above the water. Slat said they're now working to build a cork line that's three to four times higher.
"Hopefully, with this fix, we're able to safely retain the plastic," Slat said.
Once the device starts successfully retaining the plastic it gathers, the plan calls for a vessel to visit the garbage patch every few months and tow the debris to shore.
Satellites and sensors help researchers monitor the device's location
Slat said he plans to build a larger version of the system next year that could capture more plastic, though his team is still trying to determine what the precise size should be. After that, he said, the organization will construct a full fleet of these plastic-cleaning devices.
The team will use algorithms to determine where to deploy the systems so they can catch the most plastic (and won't collide with any vessels along the way).
The device that's currently in the garbage patch has solar-powered sensors that monitor the direction of the array, track the environmental conditions around it, and detect any malfunctions. The sensors are hooked up to satellites that send images and GPS information to The Ocean Cleanup researchers. The device also comes with lanterns that make it visible to passing ships.
Slat said he spends about 80% of his time these days working on the system's technology and conducting scientific research. But he rarely sees his invention in action, since he tends to get seasick.
"I'm definitely much more useful on land," Slat said. But once the system is scaled up, he added, he'll visit it offshore.
"I'd like to go at some point, but only once the whole fleet is out there," he said. "I think it'll be kind of epic to see."
Slat is confident that his strategy will work
Slat said the fact that the technology hasn't been fully successful yet is a "major bottleneck," but added that he thinks a breakthrough is imminent.
"To me, it's not really a question of whether it's going to work; it's when is going to work," he said.
Slat said he doesn't think the hype about his project has much to do with his age, especially now that he's 25, though he's fine with being called a teen entrepreneur.
"I'll be 19 years old forever, I think," he said.
What bothers him, Slat added, is that his project is sometimes described as a solo effort. The Ocean Cleanup now employees roughly 90 full-time scientists and engineers. It's also backed by major Silicon Valley donors like Peter Thiel and Marc Benioff.
"A lot of these people are technologists and entrepreneurs who understand that things require iteration," Slat said.
Regardless of what public opinion is about his mission, Slat said his reputation has never really been the focus.
"If I were to care about people's opinions, I would never have started The Ocean Cleanup," he said.