Funding Agency
Amer. Water Works Assoc. Research Foundation
Collaborators
Marios Polycarpou, University of Cincinnati
Drinking water must contain a residual disinfectant to guard against adverse health effects of pathogens. "Why," you might ask, "since distribution systems are closed systems?" In reality distribution systems are not closed; finished water storage reservoirs are vented to the atmosphere, and all distribution systems leak. And - under negative pressure transients that some investigators are finding to be common - what can leak out, can leak in. It is not easy to maintain a disinfectant residual, because disinfectants react with organic and inorganic compounds and thus lose their potency over time, as they are transported from treatment plant to consumer. When time-varying and unknown transport times are introduced - from hours to several days due to changes in consumer usage patterns over time and space - the control of disinfectant residual becomes a challenging research problem.
This project is investigating spatially distributed control systems for chlorine residual maintenance. The actuators include booster chlorination stations that are located in the distribution network, and the sensors measure the chlorine residual at critical locations, with their signals fed back to the real-time controller. In this framework, the controller must model in some fashion the relationship between booster input chlorine injections and sensor output chlorine residuals; furthermore this model must adapt in real time to common changes in this relationship, including those due to changes in water usage, network and treatment process operation, and raw water quality characteristics.
The research has developed new spatially distributed controllers and tested them in a realistic simulation environment. The controller and control system design required new algorithms and concepts to characterize the relationship between chlorine input and output concentrations, and these have been developed and tested.
With respect to the control system design problem, the number and location of actuators and sensors is critical with respect to control system performance; ongoing work is tackling this complex problem through development of an integrated systems design approach.
Summary of research results (Chapter 1 from AwwaRF report)
J. Uber Home |
Dept. Civil & Env. Engr. |
UC College of Engineering
Last Modified: 15 January 2002
