The Esposende WWTP, located in the parish of Gandra, is designed to treat approximately 6,750 m3 / day of domestic wastewater, and has the capacity to serve an Inhabitant Equivalent population of about 50 thousand. The Esposende subsystem also includes a set of interceptors, with a total length of 37.9 km, most of which have already been built, which allow the flow of effluents from the population settlements that drain into this treatment infrastructure. The start-up of the new infrastructures allows to treat the waste water and improve the quality of the water of the Cávado River and, consequently, the quality of life of the local population. The project involved the demolition of an existing WWTP and the preparation of technical studies. In addition to increasing treatment capacity, it would be necessary to deactivate the WWTPs of Apúlia, Fão and Curvos, and to re-route their respective effluents to the new WWTP of Esposende.