It has been four years since 21-year-old Boyan Slat first proposed his ocean cleanup system.

The Dutch inventor and entrepreneur was only in high school at the time but since then, he has raised $10 million through his company "The Ocean Cleanup."

Slat says his journey began because he loves to dive and was shocked by the amount of plastic he found while underwater. He tells guest host Gill Deacon, he would see more plastic bags than fish.

Artist impression of The Ocean Cleanup prototype in use. (By Erwin Zwart/The Ocean Cleanup)

Slat came up with a passive design that uses the ocean currents to concentrate debris within a v-shaped artificial shoreline moored to the seabed, cutting the time it would take to clean the ocean from tens of thousands of years to ten.

These ocean currents, they move around in these big ocean garbage patches, so I thought why would you move through the oceans when the oceans also move through you? - Boyan Slat

Testing "Boomy McBoomface"

Last week, Slat set his 100-meter long prototype into the North Sea for testing.

Slat calls the prototype "Boomy McBoomface". It currently sits 23 kilometers off the Dutch coast and it will be subjected to conditions harsher than those found in the Pacific, where the device will be put to use.

This will allow for Slat's team to test whether the design's structure will hold up to the constant thrashing of waves and storm conditions. Slat will then assess the damage and improve the design.

What about microplastics?

Critics say Slat's design fails to address the issue of microplastics.

Slat acknowledges that, but defends his design by saying that it "will be able to catch plastics down to a size of about two millimeters."

"About 98% of the mass of plastic is actually larger than that two millimeters," he says, and adds that by catching plastics larger than two millimeters, he believes his design will be able to prevent those larger pieces from degrading and adding to the issue of microplastic pollution in the first place.

The prototype of The Ocean Cleanup is installed in the North Sea. The component pictured is called the boom. (AFP/Getty Images)

What's next

Slat is planning for a full deployment of his design by 2020 and this will require hundreds of millions of dollars in funding. For now, he's focussed on crowd-funding and has a received cash from venture capitalist Peter Thiel via the Thiel Foundation Fellow, a foundation for entrepreneurs who forgo college in order to start a business.

How it works

Source:The Ocean Cleanup (text and images)