Pacific Ocean Cleanup System Aims To Collect Tons Of Plastic
The Great Pacific Garbage Patch, which covers more than 600,000 square miles between California and Hawaii, contains roughly a third of the plastic debris floating in the oceans. It’s one of the world’s five major ocean gyres — huge regions where circular currents gather trash.
Ateam led by 24-year-old Boyan Slat from the United States have hauled a 600-metre boom system from San Francisco out to the Great Pacific Garbage Patch to clean up marine plastic.
The launch of this much-anticipated project from his organisation, the Ocean Cleanup, marks the culmination of five years of research — surveying, prototyping, testing, redesigning and more testing — not to mention $31.5 million in funding. “Hopefully in the next few months, we will be able to prove that it works by taking the first plastic out of the ocean to land. And of course, that will be a very historic moment,” says Mr Slat, who dreamed up the project when he was 18.
The Great Pacific Garbage Patch, which covers more than 600,000 square miles between California and Hawaii, contains roughly a third of the plastic debris floating in the oceans. It’s one of the world’s five major ocean gyres — huge regions where circular currents gather trash.
Mr Slat’s system is essentially an autonomous boom that floats around the ocean powered by wind and currents.
“The ocean is a very challenging environment to engineer for,” he says.
The team eliminated mechanical parts and kept the boom structure flexible to help it contour to waves. (It should survive waves up to 20 metres high.) A skirt that hangs from the boom to 3 metres below the surface is a screen, not a net, to keep animals from getting entangled.
The designers factored in extra buoyancy to cope with plants, algae and other organisms that will attach themselves to the system. There are sensors to track it and estimate when it is full of plastic so a vessel can go empty it.
After the launch, team crew members will remain with the system to determine whether it traps plastic. By April, they will know if it can withstand winter storms. “It’ll be an exciting few months ahead,” Mr Slat says.
If successful, this system will bring back 50 tons of plastic after a year in operation, he says, adding that if the project is scaled up to a maximum fleet of 60, it would be able to clean up half the patch every five years.
But marine debris floating in the gyres is just a small fraction of the plastic waste entering the ocean every year. Research suggests that 4.8 million to 12.7 million metric tons of plastic waste enter the oceans per year, and estimates of what’s in the Great Pacific Garbage patch range from 79,000 metric tons to 96,400 metric tons.
The total amount of plastic floating in the world’s oceans is “less than one per cent of one year’s production of plastic,” says Marcus Eriksen of the California-based Five Gyres Institute, who was involved in a 2014 global survey that measured ocean plastic. “After 50 years of trash going out onto the ocean, only one per cent of one year?”
He says the vast majority of plastic is likely collecting in coastal areas.
“We believe much of it that’s leaving the coastlines is washing back up on shores,” he says.
That’s why there has been a movement to pick up plastic and other trash on beaches and riverbanks for more than 30 years. The International Coastal Cleanup — an annual event organised by the Ocean Conservancy — for example, will be held this year on Sept. 15.
“This feels overwhelming, and we tend to look for technology and innovation to try and solve these problems,” says Emily Woglom, the executive vice president of Ocean Conservancy. But a simple beach clean-up does produce results, she says. In 2017 some 500,000 volunteers picked up 9000 tons of trash worldwide in a single day. “There are many ocean mechanisms at play that are pulling plastic out of the system rapidly,” Eriksen says, such as tides washing plastics onto shores.
“If we can slow down the input, I’m convinced in 10 years we can see a decline. There is no need to put so much emphasis and so much money and so much effort in clean-up.”