OPTIMAL OPERATION OF MULTIQUALITY NETWORKS .1. STEADY-STATE CONDITIONS

A model is developed for optimal operation of a multiquality water-sup ply system, under steady-state conditions. The system contains: source s of different qualities, treatment facilities, pipes, and pumping sta tions. The objective is to minimize total cost, while delivering to al l consumers the required quantities, at acceptable qualities and press ures. A special approximation of the equation for water quality in pip es is used, which enables the model to select the flow directions in p ipes as part of the optimization. The steady-state operation of an exa mple system is optimized: it supplies six consumers from three sources , two of them with treatment plants, and has three pumping stations an d 10 pipes. The optimization is carried out with GAMS/MINOS, which emp loys a projected augmented Lagrangian algorithm. The example system ha s been analyzed through a base run and four additional runs, aimed at studying the effects of modifications in key data. The optimal solutio ns of the five cases demonstrate the response to changes in economic a nd operational conditions.