Real-time control of a sewer network using a multi-goal objective function

The present work investigates the use of a multi-goal objective function and a simple linear model for the minimizing of combined sewage overflow (CSO) in a sewer network during rain events. The model is based on a linear description of the transfer phenomena in the conduits and in the storage tanks. The objective function used, tries to distribute the hydraulic load homogenously over the network while keeping the inflow to the wastewater treatment plant as close as possible to constant value. The chosen description allows for a linear formulation of the optimisation problem. The approach has been tested on a simulator developed for a 24 retention reservoirs sewer network planed for the northwestern region of the Grand Duchy of Luxembourg. Furthermore the positive and negative effects of each criterion and the influence of varying the weighting of the different subgoals are analysed. Additionally, the implementation of the real time control to be realised is discussed. The benefits of the proposed approach are shown for a series of different rain events.