Application of Real-Time Control Techniques to Reduce Water Volume Discharges from Quality-Oriented CSO Devices

Abstract

This paper shows the extent to which the application of real-time control techniques can help in reducing the flows discharged from quality oriented combined sewer overflow (CSO) devices in sewer systems. To this end, a quality oriented CSO device, namely the high-crested side-weir (HCSW) with downstream gate, was taken into account for the analysis. A numerical model able to simulate routing of flows in proximity to CSO devices was specifically used to evaluate the benefits of the HCSW with downstream gate, in comparison with the more traditional low-crested side-weir (LCSW), and the coupled use of HCSWs and in-sewer mobile gates controlled in real time. The model was applied by considering four different modeling scenarios to the case study of a sewer catchment in Italy, in which real storm-water events had been recorded during previous experimental investigations. Results of the simulations prove the HCSW with downstream gate always considerably reduces CSO volumes in comparison with LCSW overflow devices. Significant additional benefits are obtained by the implementation of underflow gates controlled by real-time control (RTC), even if the presence of such mobile devices may sporadically lead to a local increase in the overflow discharge.