Buenos Aires has reached a major milestone in environmental sustainability with the launch of the Riachuelo System, the largest wastewater treatment project ever undertaken in Latin America. Divided into three main lots, two of which were built by the Webuild Group, the system is now fully operational following the commissioning of Lot 2, delivered by Webuild’s subsidiary Fisia Italimpianti.
The activation of Lot 2 marks the completion of one of the largest water pretreatment plants in the world. This strategic infrastructure project, co-financed by the World Bank, is designed to enhance sanitation for more than 4.3 million people in the Buenos Aires metropolitan region and contribute to the environmental restoration of the Río de la Plata. Once at full capacity, the system will be able to treat up to 2.3 million cubic metres of wastewater daily and extend sewer access to an additional 1.5 million people across 14 municipalities.
The activation of Lot 2 marks the completion of one of the largest water pretreatment plants in the world
Set to be handed over to client AYSA by the end of July, Lot 2 includes a 36-cubic-metre-per-second inlet pumping station, a 27-cubic-metre-per-second pretreatment facility, and an outlet pumping station.
Lot 2 plays a central role in the three-phase Riachuelo System. Lot 1 is responsible for collecting wastewater; Lot 2 handles the pretreatment; and Lot 3, also built by Webuild, manages discharge via a 12-kilometre subfluvial tunnel constructed 40 metres beneath the Río de la Plata riverbed. This tunnel, with an internal diameter of 4.3 metres, channels treated water to a state-of-the-art diffuser system composed of 34 vertical steel pipes (“risers”) that provide even and safe dispersion along the river bottom. This engineering achievement earned the project the prestigious ITA International Tunneling Award in 2021.
