In Ternay, treating PFAS in drinking water without building a new plant

The Ternay plant, located in the heart of the "Chemical Valley" and owned by the Syndicat Mixte d’Eau Potable Rhône Sud (SMEP), was designed and built by SUEZ in 2017. It supplies 170,000 users in the south of Lyon and produces 5.6 million m³ of water per year. In 2022, analyses revealed the presence of PFAS in tap water. The Syndicat sought to implement an appropriate treatment to guarantee the quality of the drinking water produced by the plant.

In collaboration with the ARS, as of spring 2022, we carried out campaigns with the SMEP to analyse PFAS in the water – from the source to the distribution network – to understand the nature of this pollution and assess the effectiveness of the existing treatment. These analyses revealed the presence of PFAS that are particularly complex to treat and which rapidly saturate the activated carbon filters. A series of laboratory tests was then carried out at our international research centre, the CIRSEE.

Several treatment solutions were investigated. The solution selected by the SMEP was to convert the six existing activated carbon filters into a Carbazur Simplex continuous-renewal reactor. This scalable, downflow innovation, patented by SUEZ, integrates seamlessly into an existing plant. In particular, it allows the frequency of carbon replacement to be adjusted in line with changes in the quality of the raw water entering the plant, and also enables the system to adapt to any future regulatory changes.

To ensure the robustness of the treatment process, an industrial pilot scheme – that is, a test under real-world conditions within the plant, with water analyses carried out every 15 days to corroborate the results obtained in the laboratory – was implemented.

This is the first time in France that this technology has been deployed to treat PFAS. The contract also includes a guarantee of PFAS removal in the water leaving the drinking water production plant, in accordance with regulatory requirements.