Now that almost 70% of the construction completed for Argentina's 'Sistema Riachuelo' project, Uruguayans are waking up to the fact that Argentina is building a a tunnel which will bring Buenos Aires' treated sewage 12 kilometers into the Rio de la Plata (River Plate). In the direction of Uruguay. Here the key word is 'treated'. Just how 'treated' will that sewage be and how consistent will the level of treatment will remain are just some important questions that keep Uruguayans awake in the nights nowadays...

Sistema Riachuelo project aims to decrease the pollution at river Riachuelo. The waters of the river flow brown because the sewage created by almost 6 million residents of Buenos Aires are discharged into this river, without any treatment. Sistema Riachuelo is a huge project with sewage treatment systems and tunnels totaling in length 40 kilometers. The plan is to treat the sewage of the city and then pumped the treated sewage 12 kilometers into the Rio de la Plata via a tunnel of 4.3 meters in diameter.

Sistema Riachuelo consists of 3 parts.The first one is a collector that begins on the left bank of the Riachuelo with more than 30 kilometers of tunnels that will convey the sewage. Running 30 meters below the bottom of the River Riachuelo, tunnels will take the sewage to the second part which is a waste pre-treatment plant. Once treated, sewage is pumped to the third part of the project which is the 12 kilometer long tunnel in the Rio de la Plata.

It is a huge project with the projected cost of 1.2 billion US$. Mostly financed with a World Bank loan of 1.085 billion dollars with the rest Argentina pays. The construction, by Agua y Saneamientos Argentinos (Aysa), duration is 11 years and it is 70% complete. 

According to a treaty between the countries on the shores of Rio de la Plata, any major work in the Rio de la Plata needs to be discussed by the countries first. As per this treaty, Argentina has presented the project to the Uruguayan delegation in 2009. Accordingto visionmaritima, Uruguayans have immediately OK'ed the project without looking into details or even asking any questions. Uruguayans started asking the questions (to themselves) only now...

https://www.visionmaritima.com.uy/noticias/actualidad-noticias/un-tunel-para-los-desechos-de-buenos-aires-atravesara-el-rio-de-la-plata-la-obra-que-lleva-11-anos-pero-de-la-que-poco-se-sabe/