Combined Sewer Network in Hilly Region: Field Survey and Pollutant Overflow Optimization

Abstract

Combined sewer networks in hilly regions present unusual and unexplored issues due to the high flow velocity which characterizes sloped systems. This work aims to present the results of a field survey carried out at the experimental combined sewer urban drainage system of Volterra (Tuscany, Italy, total surface 146 ha, maximum slope 14%). Field data have been used to calibrate the numerical model based on the network geometry and on the rainfall events of 2007 and 2008. A simple characterization of the pollutant and the analysis of their correlation with the total suspended solids have been carried out. Finally, the optimization of new designed overflow structures has been carried out based on the analysis of the pollutant features and on the evaluation of the pollutant loads delivered in the water body. © Springer Science+Business Media B.V. 2011.