Revolutionizing Sanitation: New Riachuelo Wastewater Treatment Facility Nears Completion in Buenos Aires

©Webuild Image Library

(IN BRIEF) The Riachuelo System in Buenos Aires, Argentina, is nearing its completion with Lot 2, which involves building one of the world’s largest wastewater treatment plants. Managed by Fisia Italimpianti on behalf of AySA and part of a broader initiative supported by the World Bank, the project will serve 14 municipalities and improve sanitation for 4.3 million people, with future plans to extend sewer access to another 1.5 million residents. The plant, which will treat up to 2.3 million cubic meters of wastewater daily, is supported by an extensive tunnel network positioned 27 meters below the Río de la Plata. Lot 3, already completed by Webuild’s consortium, features a 12-kilometer tunnel with an innovative diffuser system of 34 steel risers, designed for efficient water dispersion and recognized with an international tunneling award. This project is one of several major water infrastructure endeavors by Webuild, reflecting the company’s global leadership in sustainable water management.

(PRESS RELEASE) MILAN, 20-Mar-2025 — /EuropaWire/ — In a major milestone for environmental infrastructure in Latin America, work on Lot 2 of the Riachuelo System – a transformative project aimed at curbing pollution in the Matanza-Riachuelo River in Buenos Aires, Argentina – is now in its final stages. This vast initiative includes the construction of a cutting-edge wastewater treatment plant that will serve 14 municipalities and significantly enhance sanitation for approximately 4.3 million residents in the Buenos Aires region. Led by Fisia Italimpianti, a specialized subsidiary of the Webuild Group in water treatment and desalination, and executed on behalf of AySA (Agua y Saneamientos Argentinos), the project has reached 95% completion after recent successful technical testing, with full completion anticipated by the end of May.

The Riachuelo System stands as the largest project of its kind in Latin America and has garnered support from the World Bank, thanks to its profound social and environmental impact. Once fully operational, the facility will not only treat up to 2.3 million cubic meters of wastewater per day but will also contribute to improving sanitary conditions for over 4.3 million people, eventually extending sewer access to an additional 1.5 million residents. Integral to this ambitious project is an extensive network of tunnels, engineered to run approximately 27 meters below the Río de la Plata, which functions as a discharge conduit for the treated water.

Divided into three sections, the project sees Lot 2 focused on the construction of the wastewater treatment plant, while Lot 3 – already completed by a consortium led by Webuild – involved the excavation of a 12-kilometer tunnel. This tunnel, carved 40 meters beneath the riverbed with an internal diameter of 4.3 meters, is designed to channel treated water at a rate of 27 cubic meters per second. A highlight of Lot 3 is its innovative diffuser system, featuring 34 vertical steel risers, each nearly one meter in diameter, which extend to the riverbed to ensure the efficient dispersion of the treated effluent. This engineering feat earned the project the prestigious ITA International Tunneling Award in 2021. Fisia Italimpianti leads the consortium for Lot 2 in collaboration with Acciona, which holds a 65% stake in the venture.

The Riachuelo System is part of Webuild’s global portfolio of water projects. The company is also advancing the Northeast Boundary Tunnel (NEBT) in Washington, D.C., finalizing Lake Mead’s Hydraulic Tunnel No. 3 for water supply to Las Vegas and its environs, constructing the towering Rogun Dam in Tajikistan to double national energy capacity, spearheading the Grand Ethiopian Renaissance Dam (GERD) to boost hydroelectric generation in Africa, and working on Australia’s most ambitious hydroelectric venture, Snowy 2.0. These projects underscore Webuild’s commitment to sustainable development and innovative water management solutions worldwide.

Webuild is a global leader in the design and construction of large, complex infrastructure projects in sustainable mobility, hydropower, water treatment, and green buildings. A recognized leader in the water sector, it works in approximately 50 countries with over 92,000 people of 125 different nationalities. The Group boasts nearly 120 years of applied engineering on more than 3,700 completed projects, with a track record of 13,648 kilometres of railways, 891 kilometres of metro lines, 82,577 kilometres of roads and highways, 1,022 kilometres of bridges and viaducts, 3,462 kilometres of tunnels, and 318 dams and hydropower plants. Among its most famous projects: the expansion of the Panama Canal, the Long Beach International Gateway bridge in California, the Third Bosphorus Bridge in Turkey, the Sydney Metro Northwest skytrain viaduct and bridge, the Kingdom Centre skyscraper in Riyadh, Saudi Arabia, and numerous metro lines in Copenhagen, Paris, Rome, Milan, Naples, Doha, Thessaloniki, and Riyadh. Among the main ongoing projects, the following stand out: the New Genoa Breakwater, the Brenner Base Tunnel, Line C of Rome’s metro network, the high-capacity railways between Genoa and Milan, the high-speed railway between Naples and Bari, the Palermo-Catania-Messina high-capacity railway, the Snowy 2.0 hydropower scheme in Australia, and the Trojena dam network in Saudi Arabia. As of December 31, 2024, the Webuild Group registered total revenues for €12 billion and a total backlog of €63 billion, with more than 90% of its construction backlog related to projects linked to the United Nations Sustainable Development Goals (SDGs). Webuild, subject to the direction and coordination of Salini Costruttori S.p.A., is headquartered in Italy, is listed on the Milan Stock Exchange, Borsa Italiana (WBD; WBD.MI; WBD:IM), and since 2021, it is included in the MIB ESG index of the Italian blue-chip companies with the best ESG practices.

Media Relations

Francesca Romana Chiarano
Tel. +39 338 247 4827
email: f.chiarano@webuildgroup.com

SOURCE: Webuild S.p.A.