Treat wastewater and stormwater in Marseilles to protect the coast

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.

of wastewater and stormwater collection networks
of coastline
of streams to protect

Maintain, modernise and remotely monitor the network to anticipate risks

Our role had three elements:
  • Provide preventive maintenance by constant servicing of the network.
  • Modernise the infrastructures and procedures to constantly optimise their operation.
  • Dynamically manage stormwater to limit overspill of wastewater into the natural environment.
Prevent pollution
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:
  • network, inlet and grid cleaning operations,
  • video inspections,
  • leak tests,
  • flow or dredging inspections
  • preventive high water-pressure cleaning
  • wastewater treatment.
Protect the host environments
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.
Using digital technology to the benefit of quality of life
SUEZ is setting up the first French sanitation service to simultaneously manage terrestrial infrastructures and their impact on the host marine environments. The PH@RE monitoring and control centre will include 150 remote surveillance stations and 120 water level sensors to offer a global vision of the urban streams, stormwater basins and the coast by 2018.This ultramodern supervisor will allow increasingly predictive management of treatment of the community’s water.

The results

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. If pollution does occur, measures are taken immediately to stop bathing and identify the causes. This organisation achieved 98% accessibility to the beaches in 2015.

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.
million m3
of treated wastewater each year
analyses carried out during the summer on bathing water, almost twice as many as required by the regulations.
of artificial nurseries for young fish created in 2015.