Matanza Riachuelo Lot 1

Matanza Riachuelo is one of the most significant and complex wastewater treatment and environmental sustainability projects in the world. The Riachuelo River runs for 64 kilometers, crossing Buenos Aires and its province. In this historically industrialized area, the river’s water has reached extremely high levels of pollution, remaining contaminated until its mouth in the Rio de la Plata, between the neighborhoods of La Boca and the city of Dock Sud. The “Riachuelo System” involves the construction of a wastewater treatment plant and an extensive network of tunnels running approximately 27 meters below the Rio de la Plata. It all began with the “Guardians of the Riachuelo”. In 2006, a group of citizens, in collaboration with the Ministry of the Environment of the Government of Buenos Aires City, initiated a pilot plan to recover the riverbanks in underdeveloped areas that lacked regular urban waste collection services. They also monitored and reported pollution levels in the river, which ranks among the most polluted in the world. This project, born from the bottom up, was fueled by the desire to make the Matanza Riachuelo basin area more sustainable, as it is home to millions of people. Fifteen years later, the “Riachuelo System” infrastructure project has materialized as a sophisticated water treatment plant with the goal of restoring the Matanza-Riachuelo basin, which has experienced significant urban development and has been used for waste disposal by numerous industrial activities. Today, the construction of the plant is in an advanced stage, and the World Bank, among the project’s financiers, has confirmed its intention to continue investing in this complex area requalification project. The development of the Matanza Riachuelo river basin includes the left bank collector, the diversion of the Baja Costanera collector and complementary works. The effluent drainage tunnel’s route will pass under the port area of Buenos Aires.

Ghella undertook the construction of the project’s Lot 1, which was completed at the end of 2022. The main line comprises a tunnel of about 14 kilometers excavated using two Tunnel Boring Machines (TBM). TBMs are machines capable of mechanically excavating tunnels safely. The TBMs, commonly known as “moles”, excavate the rock using a rotating cutter head with cutting discs, remove the excavated material, and secure the cable realized by placing prefabricated segments. The two TBMs were given female names: Elisa and Valentina. The first one, a 3.84-meter diameter Earth Pressure Balance (EPB) TBM, excavated for a length of over 9 kilometers. Meanwhile, the second one, a 5.26-meter diameter Mix Shield TBM, dug for another 5 kilometers. Additionally, a total of 17 kilometers of branched galleries were constructed for the project, excavated using pipe jacking machines, and a 530-meter-long tunnel was excavated using conventional digging methods. The project is part of the Matanza-Riachuelo Basin (MRB) Sustainable Development Project, involving a basin with a population of 7 million people, of which 10% live below the national poverty line. The area affected by the construction activities mainly consists of highly diverse residential districts with varying socio-demographic characteristics and marginally includes industrial, storage, and commercial areas. For this reason, the needs of the local communities were placed at the center of a targeted strategy aimed at managing the expectations of all stakeholders.