sewage work - the purpose of this contractual procedure is to select the most convenient offer for the construction of the civil works of the guangarcucho wastewater treatment plant, supply, installation and equipment testing (includes a batch of spare parts for the continuous and uninterrupted operation of the station treatment plant), start-up, start-up and accompaniment to the operation of the plant, in the city of cuenca, republic of ecuador, according to the content of these bidding documents and the definitive and updated studies and designs of the project; the liquid phase treatment system is made up of conventional activated sludges and for the solid phase, thickening (under gravity for primary sludge -, creams and foams, and in bands for secondary sludge), anaerobic digestion, dehydration and generation of electrical energy from biogas, odor control systems.