OPTIMAL OPERATION OF MULTIQUALITY NETWORKS .2. UNSTEADY CONDITIONS

A model is developed for optimal operation of a multiquality water-supply network under unsteady conditions, for a time horizon that is divided into a number of time periods. The objective is to minimize total cost, which includes the cost of water at the sources, of treatment, and of the energy to operate the system. The constraints include equations that describe the change in flow and quality over time throughout the system, the physical laws of flow and concentrations, and the requirements for level of service. The equations that describe concentrations in pipes are of a form that allows the flow direction to reverse during the iterative solution process. The model is solved with GAMS/MINOS. An example system is optimized, with two sources, one with a treatment plant, two reservoirs, 6 consumers and 11 pipes, operated over five time periods. The system has been analyzed through a base run and three additional runs.