KREAN has provided technical assistance, health and safety coordination, inspection and supervision of the construction works of the Vicálvaro A sewer for the Madrid City Council. The works were received on 28 June 2023.

The Vicálvaro A collector works have been carried out to evacuate rainwater and sewage from the "Los Ahijones" sector to the Los Migueles storm pool. The new collector is about 3,500 m long, starting south of the R-3 motorway, bordering the "El Cañaveral" area, and ends 118 m before the "Los Migueles" storm pool.

The entire section was built in a trench, with sloping slopes in accordance with the geotechnical studies, except for a 116-metre section, which was supported by sheet piling .

The collector crosses the railway platform of line 9 of Metro de Madrid, between the Puerta de Arganda and Rivas Urbanizaciones stations. For the aforementioned crossing, two parallel conduits, each 91.2 m long, were driven, each made of concrete pipe with an internal diameter of 2,500 mm. The driving method was carried out by means of a tunnel boring machine with a closed shield of the hydro-shield type. This technique consists of full-section drilling by means of thrust and cut by rotation in which both the guidance and thrust are managed from a control cabin.