Decision Support Systems for Water Supply Systems

The book summarizes the results of the BMBF funded joint research project EWave (reference 02WER1323F) that was initiated to develop an innovative Decision Support Systems (DSS) for water supply companies. Operating water supply systems is complex. It has to be ensured that consumers are reliably supplied with a sufficient quantity and quality of water, as well as a sufficient water pressure at all times. In addition to a reliable water supply, consumers demand reasonable prices. For decision making and operational support, the EWave system uses newly developed integrated optimization modules. As a result, the user receives operating schedules on a 15-minute scale. For this purpose, mixed-integer linear and nonlinear mathematical optimization methods are combined. First, a mixed-integer optimization model is solved in order to derive all discrete decisions (primarily pump schedules). The idea here is to approximate the physics by piecewise linear relaxations well enough to come up with the right/optimal decisions. EWave then uses nonlinear optimization and simulation methods to get the physics straight. The process is iterated if necessary. This approach enables globally optimal solutions within an apriori given quality tolerance. Optimization results obtained in real time yield a potential of energy savings of up to 4.6 percent daily for the waterworks in the pilot area.