Construction of a network system for water treatment and supply in the city of Santana, Cantagalo district, in the island of São Tomé and Príncipe, with an extension of 7 km, in electrowelded HDPE piping, including the construction of two hypochlorite solution treatment plants and three semi-underground reinforced concrete reservoirs. This was a public contract launched by the Cascais Municipality under the framework of an agreement with the Cantagalo Municipality.