Numerical modelling of the sewer system of Rimini: CSOs reduction on the Adriatic Sea

The objective of this paper is to investigate, with the aid of a mathematical model, the sewer system of the city of Rimini. The city has an economy based on tourism, the activations of the CSOs along the coast, especially during the summer, determines great problems both environmentally and economically. The first part of the study shows the calibration of the hydraulic model of the sewer system that has been made in detail on the whole territory of Rimini. Real time control system allowed to have available a large amount of data usable for the calibration both in dry weather and in wet weather conditions. The second part of the study focuses on two of the eleven Combined Sewer Overflows (CSOs) present on the coast: Colonnella I and Colonnella II. In particular it was evaluated the efficiency, in terms of number of spills during rainfall periods, with different configurations. The simulation of the three different scenarios shows the benefit due to Real Time Control (RTC) and to the tanks in terms of spill reduction to the Adriatic Sea.