In France, protect the wealth of Marseilles’ natural heritage by a smart sanitation service

When hit by periods of heavy rainfall, Marseilles is prone to severe flooding which can cause untreated stormwater to overflow into the environment. The treatment of wastewater and stormwater is a crucial issue to limit pollution and protect the Mediterranean marine environment in the heart of one of the most visited regions in France.

For over 10 years, SUEZ has been working with the Communauté Urbaine Marseille Provence Métropole to offer its 850,000 inhabitants a thoroughly renovated and innovative public sewerage service. Thanks to massive investments made by SUEZ, the municipality today has one of the most efficient sanitation services in France.

Our role had three elements:

 

In Marseilles, the 1,950 km of wastewater and stormwater network are subject to attack on various fronts linked to the materials conveyed in the pipes, the waste flowing through them and sometimes blocking them, and the levels of flow which vary according to the weather. Our teams guarantee the proper functioning of the sewerage system:

 

When violent storms hit Marseilles, the stormwater runs over the ground and becomes loaded with effluent. To reduce the flow of this water in the natural environment, SUEZ built a large 50,000 m3 stormwater retention basin. The water collected is then sent to the Geolide wastewater plant (up to 2mm/hour), to be treated, thus avoiding any pollution of the bathing water.

 

SUEZ has set up the first French wastewater service to simultaneously manage terrestrial infrastructures and their impact on the host marine environment. The collection of wastewater and rainwater is optimised thanks to a network control centre, Le PH@RE. It integrates remote surveillance stations and water level sensors to offer a global vision of urban streams, stormwater basins and the coast.
This ultramodern supervisor distributes the hydraulic load over the catchment area, using innovative interconnected technologies, and allow increasingly predictive management of treatment of the community’s water.

 

In 2017, each time it rains, it will be possible to store up to 50,000 m3 of wastewater and stormwater upstream of the wastewater plant. After the rain, the basin will be emptied within 24 hours through Géolide, the wastewater plant.

The infrastructure will avoid 1 million cubic metres of untreated water per year spilling into the “calanques” (rocky coves).This is a 50% reduction in relation to the current situation.

Daily analyses of the bathing water are carried out on 21 beaches. Thanks to the GenSpot molecular biology analysis method developed by SUEZ, the results are delivered to the municipality in less than three hours. These data are shared with residents via a dedicated application to find out about bathing conditions in real time. If pollution does occur, measures are taken immediately to stop bathing and identify the causes.

Finally, to revitalise the natural ecosystems, SUEZ has initiated various pilot schemes aiming to analyse the impacts of the region on the marine environments, reintroduce endemic seaweeds on the coast and create habitats for young fish in the Vieux Port.