Fighting plastic pollution with air bubbles

Innovative Dutch start-up The Great Bubble Barrier® has developed a barrier system which consists solely of air bubbles in the water. It forms a partition designed to keep plastic waste from reaching the open sea, at the same time pushing it up to the surface.

The plastic waste washed up in the channel at the Dutch seaside resort of Katwijk can be seen from far away. Vast quantities of brightly coloured plastic bags, bottles and sheeting pile up in The Great Bubble Barrier’s collection system. What at first glance appears a colourful sight, in fact represents a major problem – the accumulated rubbish not only pollutes the river, it also destroys the natural habitat of many different animals and plants.

For mission like this to succeed, sophisticated technology is needed. The resourceful minds at this Dutch company had a brilliant light-bulb moment: Why not collect the rubbish with the aid of compressed air? And that’s precisely how this simple yet innovative system works: Compressed air is pumped through a perforated pipe at the bottom of the waterway, creating a bubble curtain – the so-called “Bubble Barrier”. The bubble barrier produces an upwards flow, which carries the plastic up to the water’s surface. By arranging the partition diagonally across the river, the natural flow of the water pushes the plastic waste to the side and into a collection system. Then, the collected plastic is removed and processed.

Philip Ehrhorn recounts the story of how The Great Bubble Barrier came about: “Founders Marieke Eveleens, Saskia Studer and Francis Zoet are friends and lifelong sailors. During their sailing trips, they would always come across plastic floating in the sea. So in 2015, they got together over a beer to think about how they might actively combat plastic pollution. From these discussions, an idea quickly came about. Inspired by the bubbles in their beer, the first prototype was soon being tested. In parallel, the fourth founding member, Philip Ehrhorn, was developing his own Bubble Barrier in Germany. The best elements of both systems were combined and, in 2017, The Great Bubble Barrier was officially launched.

“Five years of research and development and three pilot projects later, we’ve now developed the most energy-efficient bubble barrier system, it’s in place and it’s successfully trapping plastic pollution,” explains Philip Ehrhorn. “The unique advantages of this system are that it covers the full breadth and depth of the river, works around the clock, and has no impact on fish migration or shipping.” It was these plus points, coupled with the fact that they could provide the applicable system and, above all, the eco-friendly nature of the mission, which convinced KAESER to become part of this exceptional project. “The objectives of The Great Bubble Barrier are completely aligned with our company values,” explains Tizian Dekorsy, Product Manager – Rotary Screw Compressors at KAESER.
“Sustainability and energy-efficiency are central themes of our product development, so we are very happy to be in partnership with The Great Bubble Barrier.”

At Katwijk, an energy-efficient rotary screw compressor provides compressed air around the clock. Installed inside a container to protect it from the wind and the weather, and equipped with the SIGMA FREQUENCY CONTROL (SFC) variable speed control, this durable machine can operate at 100% duty cycles to provide precisely the amount of compressed air required by the application for the production of bubbles. A further advantage is the high dependability of the rotary screw compressor, which guarantees maximum availability of compressed air supply to ensure that the Bubble Barrier operates without interruption and therefore keeps the waters protected at all times.

“We felt from the beginning that KAESER were invested in our Bubble Barrier project and felt themselves obliged to provide the best product and service possible,” emphasises Philip Ehrhorn. Our engineers work continuously with the KAESER team and highly value their support and availability. Since every location is different, we need partners who are engaged and flexible, which is why our partnership with KAESER works so well.” 

The project in Katwijk shows once again how innovative ideas coupled with decades of experience in mechanical engineering can produce spectacular results. As its next target, The Great Bubble Barrier set the polluted rivers of Europe and Asia firmly in its sights. It is from here that most of the brightly coloured plastic waste in the world’s oceans originates. KAESER will be with them every step of the way. Philip Ehrhorn summarises: “A real spirit of partnership and cooperation has grown between KAESER and The Great Bubble Barrier, which has proven itself across many projects. From the very beginning, KAESER showed support and engagement with our mission and is always ready to assist with another successful Bubble Barrier project.”