Optimal Operation of Sanitary Pump Stations with Energy Storage During Power Outages

This paper aims to determine the optimal strategy to operate the pump in a sanitary pump station (SPS) to minimize its energy consumption over a specified time window. An SPS collects sanitary waste from nearby neighbourhoods in a city and then pumps the waste to a treatment plant for processing. Sustained operation of SPSs, even during power outages, is critical for the health and safety of urban dwellers. Energy storage can be used to operate the SPS when power from the grid is unavailable. Major challenges in minimizing energy consumption include (i) the nonlinear power characteristic of the pump, and (ii) the uncertainty in predicting the waste deposited into the SPS. We formulate a chance-constrained nonlinear optimal control problem and further devise a tractable solution strategy. We illustrate the energy savings obtained with the proposed control over the existing one.