Wedoany.com Report-Jun 24, Buenos Aires has advanced its environmental sustainability efforts with the operational launch of the Riachuelo System, Latin America’s largest wastewater treatment project. Developed in three phases, with two constructed by the Webuild Group, the system achieved a key milestone with the commissioning of Lot 2 by Webuild’s subsidiary, Fisia Italimpianti, in June 2025.

Buenos Aires takes a major step toward environmental sustainability with the launch of the Riachuelo System, the largest wastewater treatment project ever built in Latin America.

The Riachuelo System, a strategic infrastructure initiative co-funded by the World Bank, will improve sanitation for over 4.3 million residents in the Buenos Aires metropolitan area and aid the environmental restoration of the Río de la Plata. Once fully operational, it will process up to 2.3 million cubic meters of wastewater daily, extending sewer access to 1.5 million additional residents across 14 municipalities.

Lot 2, set for delivery to client Aysa by July 2025, includes an inlet pumping station with a 36 cubic meter per second capacity, a pretreatment facility handling 27 cubic meters per second, and an outlet pumping station. This phase is integral to the system’s three-part structure: Lot 1 collects wastewater, Lot 2 manages pretreatment, and Lot 3, also built by Webuild, discharges treated water into the Río de la Plata through a 12-kilometer subfluvial tunnel, located 40 meters below the riverbed. The tunnel, with a 4.3-meter internal diameter, features a diffuser system with 34 vertical steel pipes for safe, uniform water dispersion. This engineering achievement earned the project the 2021 ITA International Tunneling Award.

A Webuild spokesperson stated: “With the Riachuelo System, Webuild reaffirms its commitment to sustainable development and water resource protection, helping to improve quality of life for millions.”

Webuild, a global leader in water infrastructure as recognized by ENR rankings for over a decade, is involved in major projects worldwide, including the Northeast Boundary Tunnel in Washington, D.C., the Rogun Dam in Tajikistan, the Grand Ethiopian Renaissance Dam, and Australia’s Snowy 2.0 hydroelectric project. The Riachuelo System underscores Webuild’s expertise in delivering complex, sustainable infrastructure that enhances environmental and community well-being in Buenos Aires.