a revolutionary ecological dam to stop plastic in the Garonne

At first glance, it looks like a nautical area. A sort of long yellow and black snake “bars” the Garonne diagonally over a length of 300 meters at the exit of Toulouse (Haute-Garonne), from the Ancely bridge, right bank, to the Blagnac bridge, left bank. A new Toulouse Plages? No way. This is the first ecological anti-plastic barrier in France. Its objectives: to improve the cleanliness of the river and reduce ocean pollution downstream.

“This is the reason why, in 2017, Alexis Eskenazi and Anthony Coulon designed the first prototype,” explains Patrick Thaunay, co-founder of the Toulouse start-up Plastic Vortex, creator of the filter dam. “This concretely responds to an immense invisible scourge. In France, between 250 and 500 tonnes of plastic pass through rivers to the sea each year. At least 80% of marine pollution is of land origin. Everything we throw away outside the trash cans, in the streets, on the sidewalks or roads, goes through the rainwater drains and ends up in the river. Acting at the source is therefore a crucial lever.” When the Garonne flows through Toulouse, it has already traveled approximately 260 km and drained numerous tributaries.

Installed at the start of summer 2025, the dam, which does not prevent the passage of aquatic fauna or the navigation of canoes, has been operational since mid-September. It is based on a V-shaped structure, positioned in the direction of the current. This form is used to channel floating waste towards a collection area.

A 40 cm deep rubber skirt captures all macro-waste and micro-waste from 1 mm in diameter, which is carried, by the force of the current, to the fully automated mechanical collection system, located on the left bank. A 12 meter conveyor belt then lifts them to a 16 m3 sorting bin. The waste is sorted, quantified, weighed and revalued.

Pollution uncovered

Cigarette butts, plastic bottles, aluminum cans, food packaging… “We also recovered other unusual objects, such as a Virgin of Fatima, a boat buoy, flip flops… And, above all, aquatic plants stuffed with polystyrene balls. We are revealing the micropollution of our rivers! The installation will make it possible to catch up to 8 tonnes of plastic per year, the equivalent of 425,000 bottles which will not reach the Atlantic,” predicts Patrick Thaunay.

“It’s great! It is essential that you have put such a machine in place, because the pollution of the Garonne cannot be seen,” says a Blagnac resident walking her dog. Like her, a jogger stops to discover with amazement the incredible array of polystyrene balls: “I hope that this will help stop the microplastics that we swallow without realizing it,” she declares.

Strategic areas under study

As a small crowd formed with the arrival of Benoît and Philippe, two co-financers of the project, Patrick Thaunay continued: “The dam works even during floods. In the event of exceptional flooding, a safety mechanism is triggered to open the dam in two. When the rising water has calmed down, simply rearm it. There is no equivalent in the world.” The team also designed the Vortex 300 VN, a barrier for waterways, with several levels, to let boats pass.

It was designed to be as less polluting as possible. Its operating cost is between three and five million euros per year. “We received grants from BPIfrance, a public investment bank, the Adour-Garonne Water Agency and the Occitanie region. The project, supported by Toulouse Métro pole, currently has more than thirty subcontractors.”

The Plastic Vortex company carried out scouting in France. The team plans to install thirty-one dams in strategic areas, notably on the other major, most polluted rivers – Rhône, Seine, Rhine and Loire -, with a collection capacity of more than 175 tonnes of plastic per year. To do this, it is entering a second phase of searching for capital and an industrial partner. All he needs is a navigator godmother to help him gain fame in his quest to protect the oceans from inland.