Nocturnal setup of the water hammer arrestor for the new treated water sea discharge pumping station
27 January 2026This operation is part of the first structure to be commissioned for the new Haliotis 2 Wastewater Treatment Plant.
The civil engineering work on the structure is in its final stages, with preparations for watertightness tests underway and the installation of mechanical equipment beginning.
But what is a water hammer arrestor, and what is its role?
A water hammer arrestor is a technical device that is essential to the hydraulic operation of a pump. It protects the sea outfall by eliminating the effects of water hammer, which occurs when fluid flows through a pipe and a sudden change in flow causes an intense pressure wave that can damage infrastructure. Protecting industrial heritage is a major challenge for the Eau d’Azur water authority.
The operation took place at night.
The installation was carried out at night, partly due to traffic restrictions on the special convoy that transported the equipment from its place of manufacture (Migennes, France) and partly to limit the impact on other work in progress and ensure the safety of the teams. This operation, carried out by the sea on a site with limited space such as the Haliotis site, required a high level of technical expertise and rigorous organisation in order to lift and install this very large piece of equipment (13 metres high, 3 metres in diameter and weighing 21 tonnes) in a very complex environment.
The new pumping station is scheduled to be commissioned in autumn 2026.
Stay tuned to follow the next steps in this renovation project, undertaken for a cleaner future!