A control-oriented approach to water quality modeling of drinking water distribution systems

An input-output model is developed to relate chlorine supply concentrations at treatment stations to chlorine concentrations at specified nodes within a drinking water distribution system (DWDS). A concise history and background of water quality modeling is given in order to facilitate the input-output model development. The motivation for an input-output modeling approach is to provide a framework which is suitable for parameter estimation and control system analysis and design. The model consists of two algorithms: the first determines the length of time water spends in a particular pipe and finds the node at which the water entered the pipe. The second algorithm recursively back-tracks through the DWDS to find when and where the chlorine was introduced into the system. The input-output model accuracy is illustrated by simulation results using real data obtained over a 24-hour experiment.