Meet Mr Trash Wheel – and the other new devices that eat river plastic

From bubble barriers' to floating drones, a host of new projects aim to stop plastic pollution before it ever reaches the ocean

The Great Bubble Barrier is just that - a wall of bubbles. It gurgles across the water in a diagonal screen, pushing plastic to one side while allowing fish and other wildlife to pass unharmed.

The technology, created by a Dutch firm and already being used in Amsterdam, is being trialled in the Douro River in Porto, Portugal, as part of the EU-supported Maelstrom (marine litter sustainable removal and management) project.