The groundbreaking marks an important milestone for the new intermunicipal wastewater treatment plant in Lavasson.

A few months after the approval of the CHF 93 million construction credit by the 21 partner municipalities, the project is entering a more visible phase: the construction of the concrete structures.

Work began at the end of 2025 with earthworks. The groundbreaking now signals the arrival of tower cranes and the concrete batching plant, marking the true start of the vertical construction phase.

The future facility, designed for a capacity of 72,500 population equivalents, will replace the existing plant, which remains fully operational during the works and has reached its limits. It will include nitrogen removal and micropollutant treatment, both of which are absent from the current infrastructure.

The new WWTP will be organised around five functional units: pretreatment, biological basins, micropollutant treatment, sludge treatment and the administrative building. Two pumping stations will convey wastewater from the lakeside plant to the new site. Construction requires an excavation depth of 4 to 5 m and approximately 40,000 m³ of material, part of which will be reused as backfill. The tanks and underground structures will be built with watertight reinforced and prestressed concrete, while above-ground buildings will be constructed with locally sourced timber from member municipalities.

The next phases will progressively bring the structures out of the ground and prepare the commissioning of this essential regional installation.