Optimized Real-Time Control of Combined Sewerage Systems: Two Case Studies

The paper presents results of two case studies of Real-Time Control (RTC) alternatives evaluations that were conducted on portions of sewerage systems near Paris, France and in Quebec City, Canada, respectively. The studies were performed at real-scale demonstration sites. RTC alternatives use dynamic mathematical modeling and simulations to develop a program for a specific sewerage system to guide operation of automatic regulators when wet-weather flow is approaching. Advanced RTC alternatives also use a radar-based rainfall measurement and forecasting tool. Thus, the function of RTC-based combined sewer management is to assure efficient operation of the system and to maximize storage capacity of the existing sewerage facilities to contain combined sewer overflow (CSO) and there is cost saving aspect of this function. The first case study was conducted on a site, located northeast of Paris, France, that was a portion of the Seine-Saint-Denis combined sewer network with independent capture from other parts of the network. This site, controlled by six regulators, includes a primary settling and storage facility of 200,000 m³ capacity, which can be operated either to increase settling efficiency of the retention pond or to increase the sewer relief capacity to decrease flood risk. This case study compared two RTC alternatives: the presently used Supervisory Predictive Control, aided by a radar-based CALAMAR system, and, a simulated, Local Reactive Control, without CALAMAR. The Supervisory Predictive Control was shown to be superior.