Résumé

Water management is a recurring problem that has occupied mankind for years. Nowadays, the multiple stakeholders involved in this management have the willingness to cooperate to make it more integrated and take into consideration all social, economic and environmental components across an ideal functional unit which is the hydrological watershed. The urban wastewater system plays a central role because of its triple dimension Sewer, Wastewater treatment plant, Receiving water and well often determines the quality of the water on which depend many other sectors. Insurance that the system is in a good health allows having a functional and efficient water resources management. This work explores the possibilities of optimization of the urban wastewater system by the establishment of an integrated management which takes into account the three subsystems. For this, an understanding of the process of optimization and the knowledge about the conventionally used algorithms is deepened. Furthermore the importance of modeling and real time control for the improvement of knowledge and decision making is emphasized by a review of the available tools involved in concrete examples. An approach of integrated management of the urban wastewater system is proposed, focusing on two aspects : the identification of the critical points of the system by analyzing performance indicators and the implementation of the optimization process. This approach is applied to a case study and allows highlighting the presence of important overflows at a pumping station due to the infiltration of parasitic clean water. At this problematic station the optimization process is applied with the help of CVX tool on matlab. This optimization reduces spills using existing infrastructure while following sizing, economic and environmental constraints established by the system. This study shows that improvement of the urban wastewater system performance by following an integrated management approach exists and can be considered in Switzerland.

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