The equipment is, for the moment, unique in France and even in Europe. This is why many elected officials and technicians made the trip. The first unit for producing drinking water obtained from wastewater was inaugurated Thursday in Sables d’Olonne, in Vendee. The plant, which will operate on an experimental basis only for one year, will distribute its first glasses of water to the inhabitants of around fifteen municipalities at the beginning of 2025. And if all goes well, it will provide, by 2027, no less of 600 m3 of drinking water per hour, the equivalent of the consumption of 60,000 people.
“It is no coincidence that this project saw the light of day in Vendée,” says Denis Guilbert, director of Vendée Waterthe water company behind this program called Jourdain. “The department, like many other coastal areas, is subject to strong pressure on drinking water resources, especially in the summer period. Until now, waste water purified by sewage treatment plants was discharged into the sea. This water, instead of losing it in the ocean, could be reused for something useful, drinking it for example. »
“Indirect” water purification to comply with regulations
Consuming waste water from sinks, showers or toilets, after various treatments of course, is already practiced in some countries, such as Namibia, the United States or India. But in Europe, “the regulations do not allow it,” recalls Denis Guilbert. To be authorized to launch, the Jourdain program therefore uses “indirect water treatment”: the water reprocessed by the Sables d’Olonne unit is not sent directly into the public distribution circuit but is first conveyed into a reservoir (the Jaunay reservoirnorth of Les Sables) serving as a reserve for the final pumping of drinking water.
Before reaching this point, the waste water had been cleaned for the first time in a treatment plant. Arriving in the so-called “refining” unit of Sables d’Olonne, it is then filtered in several stages, in order to be free of “suspended matter, bacteria, viruses and pollutants”, then disinfected with ultraviolet and chlorine. . “It is a latest generation technology, which has already proven itself elsewhere. The water obtained will be of very high quality,” assures Jean-François Nogrette, director of Veolia France, the company which operates the plant on behalf of Vendée Eau. At the end of a route of 27 kilometers of pipes, the water thus made potable even crosses a “vegetated transition zone” with the aim of being “naturally enriched with minerals”.
The Jourdain program processing unit will have cost 24 million euros, half of which was financed with public subsidies. “It is being carefully observed by many communities interested in duplicating the model. It’s up to us to demonstrate that it’s possible,” says Denis Guilbert. The final cost of the project could ultimately exceed 40 million euros.
In its Water plan presented last March, the government made the reuse of treated wastewater one of its main objectives. The rate of wastewater reuse in France is currently below 1% and is limited to non-potable uses (golf, agriculture, etc.).