Casablanca is the largest city in Morocco, with a population of around 3.8 million. The city hosts the country’s largest port and serves as Morocco’s economic hub, while also being a key tourist destination.

Beneath this bustling metropolis runs a 2.5-meter diameter concrete pipe designed to collect wastewater and sewage from the residents. Spanning 24 kilometers, the project is a collaboration between French and Moroccan partners.

To prevent damage and protect the concrete, the interior of the pipe was treated with six layers of Controll Innerseal. The impregnation process was carried out using a specially designed trolley, covering a total of 117,000 m²