Author(s): Tobias Bleninger; Laura M. Perez; Hugo Milli; Gerhard H. Jirka
Linked Author(s): Tobias Bleninger
Keywords: Outfall; Multiport diffuser; Head loss; Port; Riser; Duckbill; Manifold
Abstract: A new program for internal diffuser hydraulics is applied for the design of the Berazategui sewage outfall serving the metropolitan region of Buenos Aires, Argentina. It is planned to discharge treated sewage with a maximum flow of 33. 5 m3/s via a 7. 5 km long outfall including a three km long multiport diffuser section into the very shallow waters of the Rio de la Plata delta with about 4 to 7 m water depth at the diffuser location and tidally influenced currents. Detailed calculations for the internal manifold hydraulics in the outfall pipes show a strong sensitivity on the representation and formulation of local losses even for relatively simple riser/port configurations. An optimization methodology yielded a homogeneous discharge distribution along the diffuser, minimization of the total head and prevention of sedimentation or ambient water intrusion in the diffuser under varying inflow and ambient conditions. The final design achieves lower costs for material use and operation as well as the minimization of environmental impacts and operational stability for off-design conditions.