ABSTRACT
The “Desarrollo Sustentable de la Cuenca Matanza-Riachuelo - Lote 3” project includes a gravity outfall system to discharge treated wastewater into the River Plate, in Buenos Aires (Argentina). It consists of: 50 m deep upstream shafts; 10.5 km long sub-fluvial outfall tunnel; 1.5 km long diffuser tapered tunnel; 34 risers to discharge the effluent from the diffuser tunnel up to the river bed diffuser heads. An innovative method has been developed (the “Riser Concept”) to install vertical risers by jacking pipe segments from inside the tunnel upward to the river bed and through soil formations. The method provides several benefits, of which: reduction of maritime activities; construction schedule not affected by marine conditions; minimization of navigation traffic disruptions; environmental benefits; improvement of efficiency during construction and operation. This is the first time that this method will be used and it will represent an important step forward in sea outfall technology.
