Study: Cleaning ocean plastic now will catch big pieces before they degrade

The research vessel Ocean Starr returned to San Francisco Aug. 23 carrying tons of plastic waste — from unidentifiable shards to a 1-ton fishing net — pulled from the waters between California and Hawaii.

The crew had trawled part of what is called the Great Pacific Garbage Patch for about a month with volunteers on about 30 other boats as part of the Ocean Cleanup, an organization raising money and developing technology to deploy a cleaning system.

The members of the “Mega Expedition” docked with some potentially troubling numbers to crunch and one shred of good news.

The volume of marine pollution in the gyre's rotating current could be worse than some estimates, which put it at an area covering twice the size of Texas. However, much of the debris collected was medium to large in size and has not degraded into little bits that would be hard to recover.

Still, the need to act is urgent, according to Boyan Slat, a 21-year-old Dutch diver who raised $2.27 million through crowdfunding site Kickstarter to launch the Ocean Cleanup.

“If we don't clean it up soon, then we will give the big plastic the time to break down into smaller and smaller pieces,” Slat told reporters at a news conference in San Francisco. “Based on what we've seen out there, the only way to describe the Great Pacific Garbage Patch is a ticking time bomb.”

Slat said a report about the data gathered by the Mega Expedition will be published in the first half of 2016. In the second half of next year, he hopes to test a mile-long floating barrier to capture plastic garbage near Japan.

The ultimate goal is to find a way to undertake a massive “passive cleanup” with a 60-mile floating boom (moored to the sea floor) guiding plastic to a mechanical extraction system, possibly a conveyor belt. The marine debris then would move to a platform with a storage hull and processing equipment, like a shredder, on a solar-powered deck. The plastic would be shipped every 45 days or so to land, where it can be converted into energy or recycled.

The Ocean Cleanup estimates it could extract 42 percent of the debris from the patch in 10 years, and its technology would be 33 times cheaper than more conventional clean-up methods, such as vessels with nets, which would be essentially fishing for plastic. The group puts its cost at 317 million euros ($363.19 million).