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A wastewater treatment solution tailored to the environmental challenges specific to Grand Lieu

Located in a Natura 2000 nature protection area, the joint communities authority of Grand Lieu in the Loire-Atlantique region of France is home to a lake protected by many environmental measures and a series of designations, including regional and national nature reserve, Ramsar (wetlands of international importance) and ZNIEFF (nature zone of special ecological, plant and animal interest). The plant and animal life in and around the lake is quite exceptional. It includes 270 bird species, 19 reptile and amphibian species, 30 fish species and around 50 different types of mammal, including many protected, and some endangered, species.
The ability to address its environmental challenges effectively was therefore a decisive factor when awarding the wastewater treatment service management contract. We met with local authority Deputy Chairman Patrick Bertin
You recently awarded the wastewater treatment management contract to Saur. What led you to that decision, and what were the most important focal points of concern for you?

Grand Lieu Joint Communities Authority

Our joint communities authority groups together nine previously independent authorities, which until January 2017 had their own individual mains wastewater treatment services based on service contracts, the road water authorities, and other arrangements. When we took over responsibility for these services, we opted for a service concession contract awarded to a single partner organisation. Since the majority of the area we are responsible for falls within a Natura 2000 nature protection area, we placed huge importance on the level of environmental focus and performance reflected in the tender documents we received in response to the public call for tenders. The lake at Grand Lieu is a hypersensitive environment, and all water discharged into its catchment area must be of flawless quality to avoid damaging groundwater and the lake itself.


The wastewater pipeline network here is subject to extraneous water entering as a result of rainfall and abstraction. So what were your expectations in that context?
Saur clearly understood precisely why we place so much importance on this issue. So their submission went well beyond the requirements set out in the specification. Saur was able to demonstrate forward thinking and its commitment to address this issue over the long term. As a result, there will be a comprehensive analytical video survey conducted of the entire pipework network, and a huge campaign to inspect every subscriber connection has already been scheduled. Incidentally, this approach will also help us to reduce our expenditure on energy, because less ‘clean’ water treated unnecessarily means less electricity consumed.
Which other environmental issues are also being addressed over and above that of extraneous water?
Well, what we were offered by Saur is a comprehensive and holistic approach to environmental issues. This includes, for example, totally eliminating the use of plant protection products on land operated by Saur, and the re-use of treated wastewater for sprinkler systems and irrigation. Future uses for wastewater treatment plant sludge are also addressed, and this is an issue that poses a problem for our community, due to the fact that we have very little agricultural land available for it to be spread as a fertiliser. We are therefore working together on an inter-community plan for sludge spreading, and developing a solar drying system to reduce the overall volume of sludge. All of these are essential issues in the process of improving the quality of our environment. And over the next decade, we expect concrete results to emerge from the ambitious commitments made by the Saur teams.

Support for the environment and society: it’s all about managing a responsible water service

The proposals made by Saur to the Grandlieu joint communities authority are not solely limited to protecting the natural world. They are integral to a truly sustainable approach encompassing all the technical issues involved, as well as energy savings, responsible water resource management, protecting and maintaining the assets of the joint communities authority, and social considerations. Based locally, Saur is keen to work with local companies and ESAT (the French support and work assistance service) to encourage and facilitate the employment of disabled people.

Key figures

● 9 communities
● 38,000 residents, of which 10,700 are customers
● 172 km of gravity-fed pipelines and 58 pumping stations
● 14 wastewater treatment plants