Application of Real Time Control for CSO and SSO Abatement: Lessons Learned from 6 Years of Operation in Quebec City

Abstract

In 1999, the City of Quebec commissioned a global optimal real-time control system (GO RTC) with rainfall and flow predictive capabilities for its westerly district wastewater system. This GO RTC system served mainly to reduce separate and combined sewer overflows in the St. Lawrence River and in the St. Charles river. The project involved the implementation of five flow regulation sites in order to take full advantage of excess conveyance, treatment, and in-line storage capacity whenever available. This first phase of the project was a world premiere for this level of realtime control. Now, other communities have taken Quebec City’s lead and have implemented such real-time control systems, such as Montreal and Louisville, KY. The design and operation of real-time control in Quebec City drew upon six years of operational experience in order to, among others:  Meet and exceed the expected performance defined in the RTC studies;  Evaluate the behavior and performance of real-time control under various weather and system degradations;  Analyze and assess critical elements in the integrated chain of control from the field to the central station;  Refine the design of real-time control systems to ensure safety, reliability, adaptability and flexibility;  Enhance the central decision support system, the Csoft software;  Better integrate operational needs through RTC system implementations; and  Modify RTC measurement and control techniques for better results in various hydraulic conditions.