BUBBLE LETTER A TRIAL
BUBBLE LETTER A PLUS

“We released them at several points and counted how many were captured,” he says. Dr Frans Buschman, a researcher in environmental hydrodynamics from the independent institute Deltares, has tested the barrier in Amsterdam, using about 1,000 tagged tangerines. “It is also difficult if there are lots of ships, and they are dredging multiple times a year.”īut many believe the technique still has real promise for specific scenarios. “One of the requests we sometimes get is for a big international port like Rotterdam – there, it’s 20 metres deep but that is out of scope,” she admits. This is one of our largest river mouths, and a really good place to put a promising pilot to work to try to reduce plastic going to the sea.”Īnne Marieke Eveleens, a co-founder of The Great Bubble Barrier, is working on scaling up the technique, discussing a potential barrier in an estuary in Portugal and another project in south-east Asia. “But with the bubble barrier, we expect between 86% and 90% of the plastic pollution to be removed. “We did a test which showed that in the pumping station, only one in 233 pieces of plastic larger than 1mm is removed from the water ,” he says. With this bubble barrier we can stop those plastics.”īas Knapp, an executive board member at the Rijnland water board, believes the bubble barrier will not prevent fish migration, and is investing €42,000 a year to run it. “We notice plastic pollution by visitors to the beach, leaving wrappers and other plastic behind, but we are also the last stop before all the plastics collected along the Oude Rijn flow into the sea. “Plastic pollution is a growing problem worldwide, affecting communities as well as the environment, Katwijk is unfortunately no exception,” he says.

Jacco Knape, the deputy mayor at Katwijk municipality, said he saw the local plastic problem with his own eyes when he was invited to a beach litter cleanup. Photograph: Cynthia van Elk/The Great Bubble Barrier

Plastic removed from waterways is sorted as part of the barrier bubble study.

BUBBLE LETTER A TRIAL

Such is the promise of this trial that it has convinced the Rijnland water board, 12 municipalities and the Holland Rijnland and Zuid-Holland regions – along with Coast Busters and local fundraisers – to invest €470,000 to build their river bubble barrier. The company, run by a team of keen sailors, surfers and water enthusiasts, won an international Postcode Lottery Green Challenge in 2018 and started its first permanent pilot in a canal in Amsterdam the following year. “Here, we get the flow from the pumping station, or the wind can also push trash into the catchment system.” “We place a perforated tube on the bottom of the waterway, at an angle, and then pump through compressed air: the rising air bubbles create an upward current that will lift plastic from the water column to the surface, and then at the surface – together with the flow of the river – it is all pushed to one side,” explains Philip Ehrhorn, the chief technology officer at the Dutch startup The Great Bubble Barrier.

BUBBLE LETTER A PLUS

Fast forward to July 2022, and Katwijk is the site for the world’s first river “ bubble barrier” – an experimental concept where a 120-metre stream of rising bubbles, plus the water current, pushes plastic waste to one side in order to be collected.

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