La Grande-Motte (Hérault)

La Grande-Motte: protecting a sensitive coastal environment

In 2011, the Community of Municipalities of Pays de l’Or entrusted Stereau with the design and construction of the wastewater treatment plant in La Grande Motte. Designed to meet the future sanitation needs of La Grande Motte, the plant ensures compliance with regulatory requirements for preserving the quality of the natural environment during both low and peak tourist seasons. It represents the largest reference in France with Stereau’s Aqua-RM® membrane process.

La Grande-Motte wastewater treatment plant (Hérault).

The challenges

  • To provide state-of-the-art treated water quality and protect the receiving environment
  • To protect resources by safely implementing the reuse of treated wastewater (REUT)
  • To eliminate any odor nuisance

Our solutions

The performance of the facility is achieved through the combination of ambitious and innovative technical choices:

The Aqua-RM® membrane bioreactor (MBR) has been implemented at the wastewater treatment plant in La Grande Motte. This technology is particularly well-suited to one of the challenges of the 21st century: the reuse of treated wastewater (REUT). By combining biological treatment and membrane filtration, this process allows for achieving water quality suitable for reuse by providing thorough retention of bacteria and suspended matter. Thanks to the Aqua-RM® membrane biological treatment, the new facility treats all the collected waters from the seaside resort and delivers water that meets the standards for “bathing water” quality, ensuring compliance with regulatory requirements for the preservation of the marine natural environment.

In order to limit the nuisances related to odors resulting from wastewater treatment and to preserve the quality of life for residents, the plant also implements Stereau’s patented odor control process: Lanodor®.

The patented Saur-Stereau Ammonair® solution was chosen for its positive impact on the station’s energy bill. This solution provides the necessary aeration to the basin in order to limit energy consumption while ensuring effective removal of carbon and nitrogen pollution.


  • An exceptional water quality enabling the preservation and rehabilitation of the natural environment
  • A thorough treatment of nitrogen and phosphorus
  • Robust and easy-to-operate technologies
  • A reduction in plant energy consumption (up to 30%) through optimized aeration
16,240 m²
of Aqua-RM® flat sheet membrane filtration
Up to
population equivalents in the summer season
80 m²
of photovoltaic panels

Other achievements

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