For Christian Estrosi, Deputy, Mayor of Nice, President of the urban community Nice Côte d’Azur, and Régis Lebigre, Mayor of Vence, the collection and treatment of wastewater are a priority in terms of environmental protection, public health, sustainable development, and tourism economy.
In this spirit and with this ambition, numerous sanitation projects have been initiated in the Nice Côte d’Azur territory, such as the new wastewater treatment plant in Vence.
Currently, the municipality treats its wastewater in two treatment facilities (the Vosgelade and Malvan plants), which, while complying with European standards, are close to saturation and unsuitable for the municipality’s population growth projected for 2025. The Community Sanitation Master Plan has therefore recommended the construction of a new single facility for treating Vence’s effluents, with a capacity of 28,000 population equivalents, expandable to 40,000 population equivalents.
– The urban community of Nice Côte d’Azur has 19 treatment plants of very different sizes and processes, spread across the 27 municipalities in the area. These plants, fed by sewers and collectors, purify the pollution produced daily by the inhabitants of the affected municipalities.
These treatment plants, especially the largest ones located in coastal municipalities, make it possible to clean wastewater to render it acceptable to the natural environment, allowing the purification process to continue naturally.
These plants treat the equivalent of 900,000 population equivalents (PE), enabling Nice Côte d’Azur to have approximately 50% excess capacity compared to the permanent population of the area. This overcapacity makes it easy to accommodate seasonal workers, treat some of the runoff water, and safeguard the future considering demographic changes. (One population equivalent corresponds to a standard discharge of about 150 liters of water and 60 grams of organic matter per day. This term applies to both urban and industrial pollution).
– Network monitoring
The European directive on urban wastewater treatment (UWWT) and French laws have established the principle of monitoring sanitation systems (treatment plants and networks).
Specifically, there is a requirement to monitor important particular facilities (storm overflows or lift station overflows) to measure possible discharges into the natural environment and the associated pollution loads. Self-monitoring is one of the tools to optimize the management of sanitation systems and to improve the quality of water bodies with the objective of the WFD 2015. Its implementation presents an opportunity to examine the operation of networks and consider additional tools for development.
In Nice Côte d’Azur, a diagnostic study of the sanitation network initially identified around 150 storm overflows and 90 lift stations in the community territory. With the help of modeling techniques, the overflow facilities into the natural environment existing in Nice (around 120) have been prioritized based on the frequency and duration of discharges. The self-monitoring of networks has been effectively implemented across the community’s territory in 2008 and 2009. Currently, nearly 20 measurement points located at the most significant discharge structures (especially those near the coast) are installed.
Moreover, Nice Côte d’Azur has actively committed to establishing a permanent diagnosis of its sanitation networks. The major objectives: understanding network operations during heavy rainfall, correlating network measurements (height, flow rates) with discharges into the natural environment and local rainfall, and highlighting any malfunctions or hydraulic disorders.
In 2010, 20 new DIAGNOSTIC PERMANENT type measurement points were installed, representing an investment of over €500,000 excluding tax. In 2011, 12 new measurement sites are expected to be installed.
In total, there are currently nearly 30 permanent diagnostic measurement sites spread across the municipalities of Nice, Cagnes-sur-Mer, Saint Laurent du Var, Vence, and Saint Jeannet. Additionally, there are also 15 measurement sites located in Nice’s main stormwater aqueducts (Magnan, Gambetta, Rivoli, Médecin, and East) and about twenty rain gauges in the NCA area.
The global hydraulic measurement network comprises 64 sites, plus the 20 rain gauges. All this data is daily transmitted remotely for analysis and use at a central station located in the offices of the sanitation, hydraulic, and stormwater department.
– The new wastewater treatment plant in Vence
The municipality of Vence – with 20,000 residents – which has a network of approximately 58 km for wastewater sanitation, currently treats its wastewater in two facilities built in 1978 and 1984 (Vosgelade and Malvan), which comply with European standards but are nearing saturation and are unsuitable for demographic developments.
Following a technical-economic study of different scenarios, the Community Sanitation Master Plan recommended the construction of a single treatment facility for Vence’s effluents, with a capacity of 28,000 population equivalents at the current site of Malvan and the installation of storage basins at each site (Malvan and Vosgelade).
The objectives of this new facility are to improve discharge quality by constructing high-performance wastewater treatment equipment that ensures no harm to ecosystems or locals and preserves the quality of the receiving environment.
Just as European legislation has shifted from an obligation of means (urban wastewater directive from 1991, which imposes standard discharge norms to all European treatment plants) to an obligation of results (the water framework directive from 2000, requiring a good ecological state for every water body), Nice Côte d’Azur has decided to start from the analysis of the natural environment and its ecological state to derive the characteristics of its treatment plants.
In Vence, the primary characteristic of Malvan is its low summer flow, which therefore required a membrane process.
– Description of the new station project
The new wastewater treatment plant will be a high-performance facility, scaled for 2025, and adaptable for the future (2050).
Site of Vosgelade: Project > Lift station + storm basin
Site of Malvan: Project > New treatment plant 28,000 PE, expandable to 40,000 PE, membrane treatment, and sludge digestion. Daily volume: 6,950 m3 / day.
The new plant will be at the forefront of sanitation and exemplary in terms of environmental respect:
Perfect landscape integration of equipment,
Water treatment by membranes,
Integrated sludge treatment on site, with digestion and energy recovery,
Fully depressurized building to limit odor nuisances,
Project integrated into a high environmental quality (HQE) approach.
– Environmental qualities
This new plant will be oriented towards sustainable development:
650 m2 of photovoltaic panels – electricity production for resale,
A cogeneration unit (powered by biogas) – heat production (for sludge treatment) and electricity (for resale),
A reversible heat pump on the treated waters – heating/cooling of the operating building,
Reuse of treated water for specific technical needs,
Rainwater recovery for irrigation,
Low-nuisance construction site – Green Construction Charter,
Operating building aiming for the BBC label (Low Energy Building),
Production of sanitary hot water by solar water heater,
Optimized management of activity waste,
Effective soundproofing of noisy premises
– Site of Vosgelade – Redevelopment
. Storm overflow (flow clipping > 650 m3/h),
. Screens + Desanders (650 m3/h),
. Storm basin of 300 m3
. Lift station (350 m3/h),
. Active carbon deodorization (1,000 Nm3/h).
– Site of Malvan – New wastewater treatment plant
. Storm overflow (flow clipping > 1,120 m3/h),
. Lift station (200 m3/h),
. Screens + Desanders (1,320 m3/h),
. Storm basin of 1,000 m3
. Biological treatment (350 m3/h),
. Membrane treatment (350 m3/h),
. Thickening, Digestion, and Dewatering of sludge,
. Physico-chemical deodorization (28,000 Nm3/h).
– Cost of the operation
Studies (Project Management, PC): €860,000 incl. tax
Works Vosgelade (Pre-treatment, Lift station, storm basin): €740,000 incl. tax
Works – Vosgelade-Malvan Transfer Pipeline: €2,400,000 incl. tax
Works Malvan (Treatment Plant): €14,500,000 incl. tax
Total Cost: €18,500,000 excl. tax
– Schedule
2010-2011: Studies
2011: Company consultations, Work contracts, Choice of Contractor
Building Permit Application
2012-2014: Works
2014: Reception of the new wastewater treatment plant
