Most ocean plastic starts off in rivers, so if we want to keep the ocean free of plastic, it’s essential we intercept river plastic before it enters the sea. Fortunately, there are already four projects that are doing a seriously good job of capturing plastic in rivers. Let’s take a look at them.

Interceptor: While the Ocean Cleanup project is still going on, the organization has also turned its attention to river plastic. The Interceptor is an autonomous solar-powered device that uses a barrier stretching across a river to collect plastic. Rubbish is funneled towards a floating processing plant that resembles a barge. The trash is passed up a conveyor belt and deposited into bins, which signal to the system when they are full so that a boat can come and pick them up for recycling. Currently, there are Interceptors operating in Malaysia, Indonesia, and Vietnam, with more planned for the Dominican Republic and the USA.

The Bubble Barrier: Waternet, which manages Amsterdam’s waterways, deploys five garbage boats that fish out 42,000 kilograms of plastic every year. Earlier this year Waternet also deployed a barrier of bubbles to tackle plastic waste in the city’s canals. The Bubble Barrier is a perforated tube laid across the bottom of the canal with compressed air pushed through it. It runs 24 hours a day, seven days a week, forming a screen that catches floating debris. Plastic pieces are caught by the bubbles and pushed to the surface, where they are carried by the current to a catchment pool.

Mr. Trash Wheel: This trash interceptor has googly eyes and its own Twitter account. It has also been scooping rubbish out of the Jones Fall River in Baltimore since 2014. Basically, it’s a vessel powered by waterwheels and the river’s current, as well as solar panels. Debris is collected by floating barriers and the wheels power a conveyor belt that transfers the rubbish out of the water and into a bin.

Floating Boom: Using technology developed for responding to oil spills, the mesh barriers collect river plastic and channels it towards a floating cage. This is used to lift the plastic up to the level of the harbor wall so it can be removed. At the moment, the Floating Boom is installed at the mouth of the Kifissos River in Athens, Greece.