17 Septembre 2026

Jourdain Vendée Programme: Storage Tanks at the Heart of Water Reuse

In Vendée, drinking water supplies come under pressure every summer. The Jourdain Vendée programme addresses this challenge in an unprecedented way in France. The initiative turns treated wastewater from Les Sables d'Olonne into a resource for drinking water production. This approach is known as water reuse, or REUT.

Between the wastewater treatment plant and the Jaunay reservoir, the treated water must be stored and secured at every stage. Storage tanks play a critical role here. They help regulate flows and provide an additional safety buffer throughout the process. APRO Industrie, a manufacturer of bolted tanks since 1987, explains the role of storage in this pioneering initiative.

Key takeaways

The Jourdain Vendée programme is one of France's pioneering projects for reusing treated wastewater as a resource for drinking water production.
Vendée Eau entrusted Veolia with the construction, implementation and operation of the advanced treatment unit. The initiative receives financial support from the Loire-Bretagne Water Agency, the Pays de la Loire Regional Council, the ERDF and the Vendée Departmental Council.
It reuses up to 25% of the treated wastewater from the Les Sables d'Olonne wastewater treatment site.
The treated water is transported to the Jaunay reservoir before being used for drinking water production.
Intermediate storage helps ensure process safety, flow regulation and operational continuity.
Bolted tanks provide a fast, modular and durable storage solution for this type of project.

A pioneering water reuse initiative in France

Vendée's water resources regularly come under pressure, particularly during the summer. The Jourdain Vendée programme was developed to provide a sustainable response to these challenges and strengthen the resilience of the region's water supply.

The objectives of the Jourdain Vendée programme

Vendée relies on surface water for around 90% of its drinking water supply. Repeated periods of drought are putting increasing pressure on this balance. Led by Vendée Eau, the programme aims to secure drinking water supplies along the Vendée coast. It is part of a broader approach focused on water conservation and resilience in the face of climate change.

The objective is straightforward: to transform part of the treated wastewater, previously discharged into the sea, into an additional resource for drinking water production.

After leaving the Les Sables d'Olonne wastewater treatment facility, part of the treated wastewater is sent to an advanced treatment unit. The resulting water is then transported through a 27-km pipeline to the Jaunay reservoir. It is blended with river water in the reservoir before being sent to the drinking water treatment plant. This route provides an additional stage in the overall treatment and monitoring process, with water quality continuously monitored throughout the system.

What is REUT?: Water reuse consists of giving water from a wastewater treatment plant a second life. After advanced treatment, the water can be returned to the natural water cycle or reused for a specific purpose. In the Jourdain Vendée project, it contributes to drinking water production.

REUT explained: the technical core of the Jourdain Vendée system

The reuse of treated wastewater relies on several advanced treatment technologies. Together, these processes further purify the treated wastewater and produce water that meets stringent quality requirements.

Key treatment and advanced purification stages

The advanced treatment unit applies several successive treatment processes to the wastewater. Each stage targets different types of contaminants:

Filtration and ultrafiltration: remove suspended solids, bacteria and certain viruses.
Reverse osmosis: removes dissolved substances and a wide range of micropollutants, including certain PFAS and pesticides.
UV disinfection and chlorination: provide additional disinfection and help control microbiological risks.
Remineralisation and reoxygenation: restore the water's mineral balance and oxygen content before it is transferred to the next stage of the process.

Together, these treatment steps ensure that the water meets the stringent quality and health requirements applicable to the project.

A strict health and regulatory framework

At the time the Jourdain Vendée project was developed, no specific regulatory framework fully covered this type of drinking water reuse scheme. The project therefore required a dedicated regulatory framework with enhanced safeguards and monitoring requirements.

Vendée Eau carries out regular analyses of the treated water. This rigorous monitoring helps protect public health and the surrounding environment. The area around the Jaunay reservoir is also subject to ongoing environmental monitoring.

Why is storage essential to Jourdain Vendée?

Treated wastewater flows are not constant. They can vary depending on the season, weather conditions and the operating conditions of the wastewater treatment facility. Storage tanks help regulate these flows and maintain a stable supply between different stages of the treatment process.

They also provide a safety buffer in the event of an interruption or incident affecting the treatment process. This additional storage capacity helps maintain operational continuity and prevents sudden variations from being transferred directly to downstream processes.

Technical constraints specific to water reuse projects

A tank designed for water reuse must meet precise technical and operational requirements. Leak-tightness is a key consideration, helping to prevent uncontrolled releases into the surrounding environment. The tank material and internal lining must also withstand the characteristics of the stored water and any substances that may be present.

Finally, the tank must be adapted to a site that may have significant space, access or foundation constraints, particularly when located close to a wastewater treatment plant or watercourse. The choice of tank technology and manufacturer is therefore an important part of the overall project design.

Advantages of bolted steel tanks

A bolted tank is assembled on site, panel by panel. This construction method can reduce installation time compared with cast-in-place concrete tanks and simplifies logistics, particularly on constrained sites.

Tank capacity can also be adapted to the actual requirements of the project, helping to avoid unnecessary oversizing. Depending on the application, coated steel can provide effective resistance to the stored water and outdoor operating conditions.

This flexibility is particularly relevant to demonstration and evolving projects such as Jourdain Vendée, where storage requirements may change as the system develops.

Resistance, leak-tightness and durability

The internal coating used in APRO Industrie tanks is designed to provide long-term leak-tightness and protection of the steel panels. This can help reduce maintenance requirements and limit the risk of external leakage affecting the surrounding environment.

Criteria	Bolted tank	Concrete tank
Installation time	Typically a few weeks, depending on capacity and site conditions	Typically several months, depending on design and construction conditions
Capacity	Modular and potentially expandable	Generally defined during construction
Leak-tightness	Provided by the tank lining and sealing system	Depends on concrete design, reinforcement, joints and waterproofing
Maintenance	Individual components can be inspected or replaced	Repairs can be more complex and intrusive
Site adaptability	High; installation can be carried out on a suitable foundation	Generally requires more substantial foundations

Custom design and manufacture of your tanks

Every water project, whether it involves drinking water, treated wastewater or another industrial liquid, has its own technical and site-specific requirements. Our engineering department sizes each storage tank according to the required volume, site conditions, stored liquid and operating constraints.

Installation, maintenance and project support

APRO Industrie installs tanks on site, from the first bolted connection through to commissioning. We can also provide maintenance and technical support throughout the tank's service life, helping to maintain the safety, performance and durability of the installation.

Towards wider development of water reuse beyond Vendée

Other regions of France are facing similar pressures on water resources as a result of climate change and recurring droughts. Research and innovation programmes are being developed to further explore water reuse and strengthen water resilience.

Water circularity is becoming an increasingly important part of water management strategies in France and across Europe. Reliable storage solutions should therefore be considered from the earliest stages of project design, alongside treatment, pumping and monitoring systems.

Why choose APRO Industrie for tank design?

APRO Industrie supports customers throughout the tank project lifecycle, from technical design and sizing through to manufacturing, installation and commissioning.

Our expertise includes:

Project-specific design, based on the volume to be stored, the nature of the liquid, climatic conditions, site characteristics and operating constraints.
Modular bolted construction, allowing tanks to be transported and assembled directly on site without welding.
Sealing solutions adapted to the application, selected according to the stored liquid and operating conditions.
Expertise in technical and regulatory requirements, with tank sizing carried out according to the standards and specifications applicable to each project.
International experience, with APRO Industrie tanks installed across a range of markets and industrial environments.
An integrated approach, taking accessories, nozzles, internal equipment, roofs and other systems required for tank operation into account from the design stage.

FAQ: Jourdain Vendée Programme and Storage Tanks

What is the Jourdain Vendée programme?

Jourdain Vendée is a water reuse programme led by Vendée Eau. It reuses part of the treated wastewater from Les Sables d'Olonne and subjects it to advanced treatment before it contributes to drinking water production.

What is the connection between REUT and the system?

REUT, or réutilisation des eaux usées traitées, is the principle behind the project. It involves treating wastewater to the required quality and reusing the resulting water for a specific purpose. In the Jourdain Vendée system, the treated water contributes to drinking water production after passing through the project's treatment and monitoring stages.

What role do storage tanks play in water reuse?

Storage tanks help regulate water volumes and flows between different stages of the treatment process. They also provide a safety buffer in the event of an interruption or incident, helping to maintain operational continuity and prevent uncontrolled discharge into the surrounding environment.

Why use bolted tanks?

Bolted tanks can be installed efficiently on site and offer a modular solution that can be adapted to the project's required capacity. Their lining and sealing systems are designed to provide leak-tightness, while the modular construction can facilitate maintenance, modification or future expansion.

How does APRO Industrie support a water reuse storage project?

APRO Industrie designs, manufactures and installs custom bolted tanks for water and industrial applications. The company can also provide maintenance and technical support throughout the installation's service life.