Plastic pollution activists in the Netherlands are experimenting with a new bubble barrier technique to clean plastics from a river before they get taken out to sea. A pipe with holes in it is laid across the bottom of a river at an angle to the flow of water. Then compressed air is pumped into the pipe, creating a curtain of air bubbles like those from a Jacuzzi.
When bits of plastic encounter the rising bubbles, they tend to float to the surface and collect at the downstream end of the bubble curtain in a catchment basin. There they are removed from the water and disposed of properly. The bubbles do not interfere with marine life or shipping, according to The Great Bubble Barrier, which is promoting the technology.
According to The Guardian, the success of the Great Bubble Barrier at the mouth of the Oude Rijn river near Katwijk on the Dutch coast has led to similar trials in Amsterdam and other cities in the Netherlands. The local Rijnland water board, 12 municipalities, and the Holland Rijnland and Zuid-Holland regions have agreed to invest €470,000 to build the bubble barrier across the Oude Rijn river.
Jacco Knape, the deputy mayor at Katwijk municipality, says, “Plastic pollution is a growing problem worldwide, affecting communities as well as the environment, [and] Katwijk is unfortunately no exception. 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. With this bubble barrier we can stop those plastics.”
Bas 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 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 [by its filter]. But with the bubble barrier, we expect between 86% and 90% of the plastic pollution to be removed. A trial was incredibly promising. 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.”
Not Suitable For All Locations
The Great Bubble Barrier is no magic solution for all waterborne plastic pollution. High winds can push floating plastic across the barrier. Major harbors that require regular dredging, such as Rotterdam, are not suitable. Also, harbors that are more than 10 meters deep may not be good candidates for the bubble barrier.
Tim van Emmerik, an assistant professor at Wageningen University’s hydrology and quantitative water management group, says river systems differ widely and that the bubble barrier is one tool, but other options may be needed in specific locations. “When thinking about rivers globally, just imagine how widely they can vary, from narrow canals in Amsterdam and Leiden, to great deltas like the Mekong. Most tech solutions, such as the Bubble Barrier, only cover a range of them, emphasizing there will always be a need of a solution portfolio. Of course, consuming and polluting less plastics will help no matter where you go, and may in fact have the greatest impact.”
Of course, the best solution would be to make the cost of single use plastics so high that greedy corporations would think twice before using them for their products. Until then (which will occur about three weeks after Hell freezes over), ideas like the The Great Bubble Barrier can help clean up some of the world’s rivers and reduce the amount of plastic waste that winds up in the world’s oceans every year. That would be a good start toward tackling the scourge of ocean plastics.
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Source: Clean Technica