Less than a month prior to the United Nations Ocean Conference (UNOC), which will take place in Nice from June 9th to 13th, Christian Estrosi, Mayor of Nice, President of Nice Côte d’Azur Métropole, Deputy President of the Provence-Alpes-Côte d’Azur Region, and Arnaud Bazire, CEO of SUEZ Water in France, laid the foundation stone for Haliotis 2. This major construction project will give rise to Nice Côte d’Azur Metropole’s future wastewater treatment and recovery complex, that has been designed to preserve the Mediterranean Sea.

This €700 millions project will meet and exceed future environmental and health standards and support the community’s future sanitation needs. It will have the capacity to treat wastewater from 26 cities of Nice’s area, equivalent to 680,000 inhabitants.

Haliotis 2 is committed to the economic and social development of the region. 65% of the project’s turnover will be invested in the local economy, with more than 15 local companies involved throughout the construction period. 300 people work on this large-scale project (250 people on the design and construction side and 50 people on the operational side), with 123,000 hours of professional integration and 30,000 hours of training and work-study programmes.

“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 Christian Estrosi, Mayor of Nice, President of Nice Côte d’Azur Metropole, and Deputy President of the Provence-Alpes-Côte d’Azur Region.

“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 ” Thierry Déau, Chairman.

Preserving the Mediterranean Sea

in sustainable water management, supporting the ecological transition of the Nice region. This “all-in-one” plant will treat wastewater to preserve the Mediterranean Sea, reuse treated wastewater and produce new resources.

Haliotis 2 water treatment performance will exceed current health standards, eliminating nearly 90% of microplastics. In addition, the plant will optimally treat and recover sewage sludge, and recycle sand from wastewater and sewer networks cleaning products to use it in construction and public works. Indeed, sand is the second most exploited resource in the world after water¹.

Thanks to dynamic network management based on artificial intelligence, rainfall events and their consequences will be better managed. During rainy weather, it will smooth out the flows treated in the plant and optimise the filling of the Ferber and Arson basins. This will limit the risk of spills and better preserve bathing water quality.

Reusing treated wastewater

In addition, an industrial unit for the reuse of treated wastewater, with an annual recycling capacity of 5 million cubic metres, equivalent to the total requirements for watering green spaces and cleaning roads in the City of Nice, will complete the system. Also, a pilot plant installed in the unit, with a capacity of 150m³/h (out of a total of 600), will remove micropollutants (drug residues, endocrine disruptors).

Producing new resources

Finally, Haliotis 2 will set the standard for energy efficiency, contributing to the objectives of the Metropole’s Climate, Air and Energy Plan. It will produce four times more energy than it currently uses, avoiding 15,000 tonnes of CO2 equivalent per year by 2030.

The methanization of sewage sludge will produce 43 GWh/year of biomethane, equivalent to the consumption of 11,000 homes or 290 buses. The combustion of sludge will produce 26 GWh/year to supply the Ariane heating network.

Also, heat and cold recovery technologies from treated wastewater will supply the airport and the Grand Arénas district with 27 GWh/year. The installation of photovoltaic panels will enable Haliotis 2 to produce 475 MWh/year of electricity and will ensure part of the operating building’s energy independence.

Promoting the project’s integration into the local area

A 4.5-hectare island of biodiversity comprising nearly 600 trees and hedges will be created at the entrance to the town. Haliotis 2 will have 68% more permeable surfaces than now, to reduce urban runoff by allowing rainwater to return to the ground.

Running an exemplary and transparent construction project

The consortium led by SUEZ has embarked on an exemplary construction project to preserve the environment, despite a challenging location (in the heart of the city, close to the Promenade des Anglais and the airport, on the edge of the Baie des Anges) and in complete transparency with residents and stakeholders.

To this end, the partners have signed several charters and guidelines, including the Green Construction Site Charter of Nice Côte d’Azur Metropole, as well as the Nice EcoVallée Guidelines, which aim to optimise waste management and reuse of demolition products.

Finally, several public meetings (such as the quarterly Jury de Nez meetings) are organised to share the development of the project, discuss and minimise potential nuisances.

In addition, a construction site weather report is posted on the Haliotis website and at the Maison de l’Eau², to provide information on the impact of the construction, in terms of odours, noise and dust.

¹ The UN warns of sand over-exploitation around the world – notre-environnement
² La Maison de l’Eau, located on the outskirts of Haliotis 2 directly on the Promenade des Anglais, welcomes and informs visitors with a model, a permanent exhibition and, soon, a virtual tour of the future factory.