Integrated urban wastewater system operation: Performance evaluation and sewer network's operation implications

ABSTRACT The paper deals with the operation of the Integrated Urban Wastewater System as composed of the Sewer Network and associated Wastewater Treatment Plant. The performance of the integrated system is defined in terms of appropriate, selected, performance indicators of both subsystems. Both subsystems are connected and interact by a piping system. It is shown how the performance of the Integrated Urban Wastewater System is affected by various Sewer Network control scenarios: (1) only the Sewer Network outlet valve opening is controlled, (2) all the Sewer Network valves are controlled by a Model Predictive Control algorithm developed for minimizing the environmental impact of the subsystem and modified by constraining it in terms of Sewer Network outlet valve opening. More specific, it is proven that the Sewer Network outlet valve opening has an important role in the performances of the integrated system, and that already existing Sewer Network control strategies can be altered in such a way that they will enhance these performances.