Innovative solutions for an ambitious project
With more than 500 km of outfall sewers and collectors, the SIAAP is a key player in the sewer works sector of Paris and its outskirts. These structures can convey up to 100,000 m3 of effluents every day and this ends up clogging them, in particular on the collector base.
For the cleaning of the Rueil branch of Sèvres-Achères (SAR) collector, Sol Environment and BESSAC joined forces to propose innovative solutions that would resolve the challenges of this type of operations: presence of toxic gases, unsanitary working environment, productivity and effluent management.
The jobsite
The works of the upstream section of the SAR, representing a length of approximately 6,250 m and a diameter of 3.15 to 3.75 m, consisted in:
- extracting, transporting and treating cleaning products (2,520 m3),
- cleaning access manholes and certain parts of outfall base,
- treating wastewater.

Design of a new sewer cleaning machine
To increase productivity, it was decided to separate the cleaning function and the transfer of sand to the extraction hopper into two separate facilities. The two machines were therefore designed to be as efficient as possible for their function and also include the protection of operators.
Installation of a mobile wastewater treatment plant
To take the portion of the collector to be cleaned out of operation and maintain the contribution of the Marivel brook (amounting to approximately 1,200 cu. Metres per day, the equivalent of the wastewater produced by a city with a population of 5,000), a temporary purification station was set up to treat this wastewater rather than discharge untreated water directly into the Seine river.
The station operates 24 hours a day, 7 days a week and was designed by Sol Environment to ensure reliability and safety.
