Haliotis 2: A public utility project well underway

The Haliotis 2 construction site was visited by Éric Ciotti on the morning of Thursday, July 9. The objective was to observe the progress of the project, which aims to replace the old water treatment plant. Despite the constraints, the completion of the construction site is expected to be on schedule.

“This construction site is undoubtedly the most important one unfolding on metropolitan territory today. At approximately halfway through, it should be completely finished in 2030,” assures Éric Ciotti, the mayor of Nice.

Haliotis 2 is concealed in the landscape dressed with its green roof. But its discretion does not diminish its importance. On July 9 at 11 o’clock, the mayor of the Azure Coast city visited the construction site to discover the project’s progress.

In 2025, the Nice Côte d’Azur metropolis launched a major modernization project for the Nice water treatment plant. Led by Régie Eau Azur, this structure aims to improve wastewater treatment for 26 municipalities in the metropolis.

In a context of climate urgency and resource scarcity, Haliotis 2 is based on an ecological model, aimed at preserving water and adapting structures to climate change.

A construction site on track

This project does not aim to build on neutral ground. The objective is to modernize the existing site, Haliotis 1. It is about anticipating the aging of facilities by creating high-tech structures. “The challenge of this station is to eliminate the aging Saint-Laurent du Var station and all the municipalities west of Nice and on the right bank of the Var will be connected to Haliotis 2,” declares the president of the Nice Côte d’Azur Metropolis.

Régie Eau Azur wishes to guarantee long-term compliance with upcoming standards, but also to anticipate future territorial needs while being in line with environmental standards. “This is an important construction site, launched by the teams that preceded me and which I salute because it is a beautiful project. This is a construction site whose utility no longer needs to be demonstrated,” confides the mayor of Nice.

This device will be capable of producing new sources of decarbonized energy through microplastic treatment. The reuse of treated wastewater will promote a circular economy. “This is a resource factory! At each stage of treatment, matter and energy are recovered,” certifies the president of Régie Eau Azur, Hervé Paul.

Furthermore, the existing plant continues to operate during the work. “This construction site involves the deconstruction of existing facilities while allowing optimal wastewater treatment,” states the mayor of Nice.

During the visit, it was assured that the construction schedule is being maintained. From August 2026, a test commissioning of the new sea discharge station will be carried out. It will finally be launched in October of that year. Progressively, the various structures will be tested and then deployed.

Controlled constraints

The Nice metropolis is highly exposed to climate risks. Between flooding, marine surge, soil liquefaction, and earthquakes, the location of the Haliotis 2 construction site imposes conditions to which designers had to adapt.

“The terrain is poor quality, we must secure it with a soil reinforcement system. Each time we start a structure, we must carry out all soil treatment phases to prevent landslides,” states Hervé Paul.

Haliotis 2 will aim to implement more than 68% permeable surfaces compared to today. The idea is to respect the framework of the Promenade des Anglais, but also to preserve the living environment of residents. “We face technical and urban constraints with limited space, and we are also close to the airport,” adds the president of Régie Eau Azur.

The mayor of Nice assures that the site security is optimal. “All equipment is built incorporating the maximum degree of risk.”