Application of Real-Time Control and Source Control Solutions to Reduce Combined Sewer Overflows: A Review of Approaches and Performances

Real-time control (RTC) and source control solutions (SCSs) can be cost-effective and reliable ways to improve the performance and mitigate the negative impacts of urban drainage systems. In this paper, we review and discuss different approaches to applying RTC and SCSs for combined sewer overflow management. Applications of RTC and SCSs have been classified into three main categories in previous studies: (1) RTC applied individually to a sewer system, (2) RTC applied to a sewer system in addition to passive SCSs, and (3) RTC applied directly to SCSs. In this paper, we compare the RTC techniques and strategies typically employed within each category. We highlight the benefits and point out major gaps and issues that have not been investigated previously with the aim of promoting the long-term implementation of RTC for urban drainage systems. The findings indicate that RTC of urban drainage systems has been widely applied in different contexts and with different control objectives, but few studies have implemented RTC and SCSs in combination. Significant improvements have been observed in terms of both water quality and quantity when RTC and SCSs are integrated; however, more studies are required in order to resolve some technical issues and to investigate the cost effectiveness of individual and combined solutions.