Christian Estrosi, Mayor of Nice and President of Nice Côte d'Azur Métropole, along with Arnaud Bazire, CEO of SUEZ Water in France, officially marked the start of construction for Haliotis 2, a wastewater treatment and recovery facility intended to serve the region’s long-term environmental and infrastructure needs.
The €700 million project is designed to meet and surpass future environmental and public health standards, while accommodating wastewater treatment for 26 municipalities in the Nice area, covering a population of approximately 680,000.
The project also includes a regional economic focus, with 65% of the budget being reinvested locally. Over 15 local companies are involved, and around 300 individuals are working on various aspects of the development, including 250 in design and construction and 50 in operations. The project includes 123,000 hours of professional integration and 30,000 hours of training and work-study programs.
“The water resource is the major challenge of our century, particularly in our region. It is our responsibility to take concrete action to preserve it. The laying of the foundation stone for Haliotis 2 symbolically marks the launch of the largest new-generation wastewater treatment plant in France, an ecological and energy showcase for Nice. This environmental technology hub will address climate challenges and recover value from treated wastewater by producing biogas, recovering heat and reusing treated water on a large scale. It will play a key role in our Climate Plan, which aims to reduce greenhouse gas emissions by 55% by 2030 and achieve carbon neutrality by 2050,” said Estrosi.
The €700 million project is designed to meet and surpass future environmental and public health standards, while accommodating wastewater treatment for 26 municipalities in the Nice area
Thierry Déau, Chairman, added: “Haliotis 2 is designed to offer a service of excellence to residents, in terms of environmental performance, resource circularity and preservation of this exceptional site. SUEZ will deploy its expertise and technologies in sewage sludge treatment, treated wastewater reuse, and energy recovery in this unique site. We would like to thank Nice Côte d'Azur Metropole for their trust.”
Haliotis 2 aims to contribute to sustainable water management and environmental preservation in the region. The facility will integrate multiple functions, including wastewater treatment, resource recovery, and treated water reuse. It is expected to eliminate nearly 90% of microplastics from treated water, and it will also recover sewage sludge, and recycle sand from wastewater and cleaning operations for use in construction.
Advanced network management, including the use of artificial intelligence, will improve the plant’s ability to handle stormwater, optimize flow treatment, and reduce the likelihood of overflows, thereby helping to maintain water quality in the region.
A dedicated industrial unit will be built for the reuse of treated wastewater, capable of recycling 5 million cubic metres per year. This is expected to meet the entire need for irrigation and street cleaning in the city. A pilot installation will focus on removing micropollutants such as pharmaceutical residues and endocrine disruptors.
The plant also includes several energy production initiatives. Haliotis 2 is expected to produce four times the energy it consumes, contributing to the Metropole’s climate and energy targets. By 2030, it aims to prevent 15,000 tonnes of CO₂ equivalent emissions annually. Biomethane production from sludge digestion is projected to generate 43 GWh/year, and sludge combustion will provide an additional 26 GWh/year for local heating. Heat and cold recovery technologies are anticipated to supply 27 GWh/year to nearby sites including the airport. Photovoltaic panels will generate approximately 475 MWh/year for use on site.
The facility will also incorporate environmental features, including a 4.5-hectare landscaped area with 600 trees and hedges. It will increase permeable surfaces by 68% to improve rainwater absorption and reduce urban runoff.
To ensure transparent and environmentally responsible construction, the project is guided by multiple commitments including the Green Construction Site Charter and the Nice EcoVallée Guidelines. Public engagement is ongoing through initiatives such as quarterly community meetings (Jury de Nez) and regular updates via the Haliotis website and the Maison de l’Eau. These platforms provide residents with information on construction impacts, including noise, odours, and dust.
