A Framework for Modeling and Control of Wastewater Pumping Stations

In waste water pumping stations, centrifugal pumps driven by induction motors are used to transport the effluent collected from residential and commercial buildings to the treatment plants. Due to the varying nature of collected effluent rate, means of pump flow control should be applied. Recently, there is an engineering debate on either recommending frequency converters control or on-and-off control using soft starter technology. While there are obvious reward and cost of utilizing either approach, the lack of a simulation model makes the selection decision a matter of poor agreement. This is likely to happen in developing areas where abnormal running conditions such as power failure, excess flows, and lack of spare parts are frequently encountered. In this paper, a method for modeling wastewater pumping stations using the component oriented modeling language Modelica is presented. The model provides a valuable simulation tool to validate and judge on the different control schemes of these stations. This approach is applied successfully on a real pumping station located at the northern part of Gaza. The derived model facilitates tuning the control parameters and allows better understanding of the system dynamics.