When the tanks are equipped with a sump, it is also prefabricated at the factory. A geotextile felt is positioned between the geomembrane and the concrete base, to protect it from the asperities of the concrete.
Watertightness by mastic joint sealant
The application of a mastic joint sealant - polyurethane, silicone - between the metal sheets ensures the watertightness of the tank.
For the bottom of the tank, the concrete base is then treated with a water repellent.
Steel tray type self-supporting cover: protection against the intrusion of external elements