Robot arm collects floating waste in Aarhus

Stopping floating garbage before it gets to the ocean – the smart way

The Municipality of Aarhus (Denmark) has managed to collect over 100,000 items of waste from the city’s stream flowing into the sea over the past 20 months. This was made possible thanks to a unique robot arm device, which collects the flotsam and then deposits it in containers.

The device, called SeaProtectorOne, has done such a good job that the local authorities would like to rent it until February 2027. That application, designed by All in On Green, has the potential to solve the plastic pollution caused by river-based cities in Europe.

90% of ocean plastic waste comes from rivers

The robot consists of a tower mounted on land, from which extends a collecting barrier equipped with a conveyor belt and a filter unit. The barrier automatically follows the water level so that the filter unit constantly filters the water for foreign objects.

This happens in an area from the water surface and 30 centimetres below it. Experience shows that most waste floats at this depth.

SeaProtectorOne has integrated sensors that detect when the robot needs to be emptied of waste. When emptying, the filter unit is raised, and all the waste is deposited into a waste bin via a conveyor belt.

The robot is also equipped with thermal cameras that detect whether sailors, surfers or swimmers are approaching. In such cases, the robot barrier goes up and creates free passage. It can be powered either by built-in solar cells or by connecting it to the main grid.

Each year, plastic waste equivalent to the weight of 57,000 blue whales is thrown into the world's oceans. At least 90% of that plastic waste, floating around the oceans, ends up in the sea via river systems, according to the Environmental Science journal.

“In the sea, waste is quickly dispersed and difficult to collect. Whereas the current in a river makes it possible to systematically filter waste in a limited area without disturbing fish and birds,” points out Peter Grønkjær, professor of marine biology at Aarhus University.