The Shamokin Coal Township (Penn.) Joint Sewer Authority’s 2015 treatment plant upgrade and expansion, centered on two primary goals: long term control to mitigate overflows emanating from combined sewers and enhanced biological treatment capability. In order to deal with the surge events and protect the new downstream process equipment, the design team focused on augmenting plant headworks infrastructure. Wet weather surges would overwhelm the older Archimedes screw grit scheme, and because it was unable to keep up, it necessitated costly maintenance to clear the accumulated grit four times year.
When the design team undertook a thorough evaluation of various grit removal technologies that would accomplish fine grit removal while maintaining effective performance during the surge, it specified a hydraulic forced vortex grit removal system with integral velocity control technology, grit handling and dewatering components.