Petite Californie wastewater plant: major works ahead, public consultation opens on 17 November

On the border between Rezé and Bouguenais, the Petite Californie wastewater plant is the second largest in the Nantes metropolitan area. Opened in 1974, it treats wastewater from eight towns south of the Loire, equal to 180,000 residents. It is now close to its limit, and some of its equipment is old.

Nantes Métropole plans to modernise it and expand it onto nearby land, to reach 230,000 resident-equivalents. The project includes a new water intake with an 8,000 m³ storm basin, a new treatment unit, a new sludge building and a second digester. Works should start in 2030, while the plant keeps running, and the extension should open in 2033.

A first information meeting took place on 22 September at the Loire-et-Seil community centre. The public consultation will start with a public meeting on 17 November. Then volunteer residents can join three workshops between December 2026 and February 2027, the first one with a site visit. Topics include how to manage disturbance during the works and once the plant is running, especially smells.

All the views collected will be gathered in a "citizen opinion", and the elected officials will then have to respond to it.