Terrassa is a city located in the comarca del Vallès Occidental (see Figure below) with an extension of about 70.2 km² and which belongs to the province of Barcelona, one of the four provinces that are part of Catalonia, Spain. Terrassa originated as a Roman city of Egara in the 1st century, during the reign of the Roman emperor Vespasian. It was founded close to the Vallparadís torrent, which originates in Matadepera and passes through Terrassa.

Regarding GW quality, Terrassa is located in an area with good permeable and porous materials that conform the aquifer and would allow the passage of rainwater. However, a big part of its central area is an urban area, all paved with concrete and asphalt, which difficult drainage and leads to severe floods in the center of the city after storm events. The surroundings of the city center suffer a strong industrial activity which may increase the vulnerability of the aquifer due to the high pollution and the high rate or permeability.

Under the NINFA project, GW contamination will be addressed by urban runoff contamination prevention by testing optimized train of technologies to produce reclaimed water. The use of the reclaimed water for different purposes such as irrigation, street cleaning or indirect aquifer recharge will be evaluated. The train of technologies will be based on biological (Nature-based solutions (NBS), chemical (advanced oxidation processes (AOPs)), and physical processes (membranes).  This will enable the removal of HCs and MPs as well as the recovery of selected metals (Platinum (Pt) and Palladium (Pd)).