After three years of work, the Haute Tarentaise Community of Communes (CCHT) officially inaugurated the intercommunal wastewater treatment plant located in the Zone d’Activité des Colombières, in Bourg-Saint-Maurice, on Friday, October 2, 2026. This project, initiated in 2023 by the Haute Isère Sanitation Syndicate and taken over by the CCHT in 2025, represents a major investment for environmental protection in the region.
The plant's treatment capacity has been increased from 62,000 to 70,000 equivalent inhabitants. This modernization better manages wastewater volume fluctuations linked to the area's intense tourist activity. New equipment improves nitrogen and phosphorus treatment, contributing to better protection of the Isère river by limiting pollutant discharges. The renovation also included upgrading pre-treatment, biological depollution, and sludge dewatering systems, as well as enhancing deodorization and reducing noise pollution.
With a total cost of 20 million euros, the operation received support from several financial partners, including the FEDER program via the Auvergne-Rhône-Alpes Region, the Rhône Méditerranée Corse Water Agency, the Banque des Territoires, Caisse d’Épargne Rhône Alpes, Crédit Foncier, and Crédit Agricole des Savoie. The works aim not only to optimize purification and energy performance but also to improve the landscape and architectural integration of the facility.
A central aspect of the project is energy management and efficiency, aligned with the CCHT's ecological transition strategy. The new plant incorporates a sludge methanation unit and cogeneratio n. Sludge is converted into biogas, a renewable energy source producing heat and electricity on-site. This technology reduces the volume of sludge to be evacuated by 30 to 40%, placing the plant within a circular economy logic. Additionally, 250 m² of photovoltaic panels supplement renewable energy production, aiming for the facility's gradual energy neutrality.
