Towards the long term implementation of real time control of combined sewer systems: a review of performance and influencing factors

Abstract

Real Time Control (RTC) is widely accepted as a cost-effective way to operate urban drainage systems (UDS) effectively. However, what factors influence RTC efficacy and how this might change in the long term remains largely unknown. This paper reviews the literature to understand what these factors likely are, and how they can be assessed in the future. Despite decades of research, inconsistent definitions of the performance of RTC are used, hindering an objective and quantitative examination of the benefits and drawbacks of different control strategies with regard to their performance and robustness. Furthermore, a discussion on the changes occurring and projected to occur to UDS reveals that the potential impact of these changes on the functioning of RTC systems can be significant and should be considered in the design stage of the RTC strategy. Understanding this ‘best-before’ characteristic of an RTC strategy is the key step to ensure long term optimal functioning of the UDS. Additionally, unexplored potential for RTC systems might exist in the transitions, rehabilitation and construction of drainage systems. The research gaps highlighted here could guide the way for further development of RTC strategies, and enabling more optimal, long term implementation of RTC for urban drainage systems.

Costs and benefits of combined sewer overflow management strategies at the European scale

“…Real Time Control (RTC) is an emerging water management strategy (Garrido-Baserba et al, 2020;Voutchkov, 2019), that aims at using data collected in real time to adjust the operation of the system (in this case, the CS network) pursuant a goal, that in our case is the reduction of CSOs. Van Der Werf et al (2022) review RTC applications for CSO management by referring to a set of case studies (see Appendix 3). By plotting the CSO volume reduction in the case studies as a function of the initial CSO volume, we found that the reduction of CSO annual volumes could be expressed as a function of the current CSO volumes, by means of a power law equation (further described in Appendix 3) with R 2 = 0.87 and mean absolute error of 36%.…”

“…Real time control can help in CSO mitigation (Colas et al, 2004;Van Der Werf et al, 2022), and it can be classified into local control systems, or system-wide control systems, where the former type is less expensive but with less relevant efficacy at the large scale (e.g. the whole city scale) (Eulogi et al, 2022).…”

“…Pleau et al (2005) estimated the costs of real time control in CS systems in Quebec. In Van Der Werf et al (2022), additional case studies across Europe are described.…”

“…Considering the case studies listed in Van Der Werf et al (2022) on the benefits of CS digitalization and real time control (RTC), Table 1 can be compiled, extracting the original data from the case study-related papers.…”

Abatement of Sewer Overflow Pollution Based on Distributed Optimal Control Approach

“…Currently, most studies seeking the optimal strategies in controlling a sanitation system are focusing on reducing overflow volume. 48 Few studies can be found to optimally reduce the overflow mass loading, which is correlated with the overflow volume through the concentration of sewer flow and directly impacts the water quality of receiving waters. While the control of overflow volume employs hydraulic models, both hydraulic and water quality models are factored into the control of overflow mass.…”