Optimizing Functionality of Pressurized Sewerage Systems

This paper presents methods and results on optimizing the functionality of pressurized sewerage systems, specifically wastewater pumping stations. A holistic approach is introduced to address major issues in wastewater transport such as sedimentation in suction chambers and fiber-induced issues in wastewater pumps, as well as their effects and detection. A conceptual suction chamber is scaled using hydraulic similarity and is experimentally investigated regarding its susceptibility to sedimentation. Optimization of inlets and manifolds, pumps, and sloped walls contribute to minimizing sedimentation. In terms of wastewater pumps, a semi-open two-channel wastewater impeller is optimized for its efficiency via response surface optimization. The subsequent optimization for functionality showcases the nexus of the two characteristics by means of cut-back and thickened leading edges, which significantly reduce the susceptibility to clogging. Another important consideration in wastewater pump design is the back shroud cavity. Through iterative experiments with different housing recess configurations, the back shroud cavity is optimized to minimize fiber entry and protect the mechanical seal. Lastly, the demonstration of the effects of clogging in the form of transient instationarities in the torque of a wastewater pump underline the importance of optimizing wastewater pumps for their functionality and low susceptibility to clogging.