Stemming the tide of plastic pollution

The world produces 400 million tonnes of plastic every year. Over the course of that year, 12 million tonnes of it will end up in the ocean, either dumped on beaches or coastlines or swept out to sea via lakes, canals and rivers. Plastic pollution is harmful to animals that get caught in it and as it breaks down – a process that can take hundreds of years – digestible particles known as microplastics can disrupt the biology of aquatic species. Microplastics are also absorbed by humans; the consequences of which remain unknown. Evidence of microplastics has been found on the peaks of Mount Everest and in the placenta of unborn babies.

Tackling the issue before plastics enter ecosystems in the oceans is widely considered to be an efficient approach. And one startup working to stem the tide of plastic pollution flowing through rivers is The Great Bubble Barrier. The Amsterdam-based social enterprise has developed an innovative solution that uses a curtain of bubbles to capture plastic as it floats downstream. A perforated tube is placed diagonally along the riverbed and compressed air is pumped through it, creating a curtain of bubbles and an upward current that drives plastic to the surface and towards a catchment area on the bank. Other systems use floating booms to funnel or collect plastic pollution, however, this is unsuitable for busy waterways. The Great Bubble Barrier allows marine life and boats to pass through unaffected. 

It was the bubbles in a glass of beer that sparked the inspiration for the company. Three of its four co-founders, Anne Marieke Eveleens, Francis Zoet and Saskia Studer, all keen sailors, were discussing plastic pollution after a boating trip when they noticed the bubbles in their drinks. They began researching the technology and came into contact with Philip Ehrhorn, an avid surfer and diver with a background in naval architecture and ocean engineering, who was independently pursuing the same idea. He was persuaded to move to the Netherlands and merge as the fourth co-founder. Today, The Great Bubble Barrier has 11 staff. They implemented the first long-term bubble barrier in Amsterdam in 2019, and another in Katwijk, also in the Netherlands in 2022. This year it will launch a third barrier in the Porto region of Portugal.

The Great Bubble Barrier has benefited substantially from numerous awards. Among them was first prize in the Plastic Free Rivers Makathon of PWN and Rijkswaterstaat in 2016, which came with the opportunity to run a three-month pilot in the IJssel River. It has since received support from the European Union’s Climate-KIC and Horizon 2020 programmes.  And last year it was named as a finalist in the prestigious Earthshot Prize. The challenge, says Eveleens, is – and has been – remaining financially sustainable while staying focused on their mission. Projects are graded on their impact on the environment, the potential to gain knowledge, and financial benefits. “If it hits two out of these three topics we say, OK, and we go do it,” she explains. “But if it only brings financial gain, then we don’t think it’s societally beneficial enough to do so.”

Of course, one problem that can arise is that a project has a great environmental impact or offers the chance to gain knowledge, but is financially unviable. In this case, says Eveleens, they look to philanthropy or grants as a source of financing. The projects and trials to date have enabled the organisation to fine-tune its operation, which is technically simple but requires a detailed analysis of the many variables in a waterway in order to work effectively. The barrier can collect up to 86 per cent of plastic floating downstream, from broken surfboards to particles as small as 1mm. The Amsterdam barrier intercepts approximately 15,500 pieces of plastic each month.

The primary clients for The Great Bubble Barrier are governments, usually, the city or municipality working together with the water authority, and the cost, relative to municipal spending, is accessible. From design and stakeholder negotiation to installation, Eveleens says it starts at about €350,000. As the company has grown, it has been approached for more public-private partnerships. The project in Katwijk, was exceptional in that it was driven by the local community, a citizen-led initiative that created a consortium to bring together local government and businesses to install a barrier in their town.

Previously the startup chose to grow organically and not take investments, but it is now preparing for an investment round. This means adapting its business model to move faster, as well as further developing its technology so it is simpler to implement and simpler to work together with big partners beyond the Netherlands and Europe. “That’s what I’m dreaming of,” says Eveleens, “to go international.”