General assessment of potential CSO reduction by means of real time control

A number of case studies have been carried out in which the potential reduction of combined sewer overflows (CSO) by means of real time control (RTC) is assessed for existing sewer systems. It is an inherent problem of case studies that results cannot necessarily be generalized. In this paper results of a systematic investigation of hypothetical combined sewer systems are presented. The systems were characterized m terms of their topological structure, size, type and arrangement of storage and transport elements. The RTC optimization model LOCUS was applied to simulate the performance of local control and of optimum control strategies. The results are expressed as “CSO reduction achieved by optimum control, compared to the locally controlled system”. General conclusions are drawn with respect to possible CSO reduction for a system with given topology, storage and transport characteristics. Finally, these are compared to some case studies reported in the literature in order to verify and show the general applicability of the findings.