Equalization Basins - Hydraulic System

For influent flow to publicly owned treatment works (POTWs), flow rates may be excessive for short or long durations, especially in combined sewer systems. If the influent flow rate exceeds the capacity of the wastewater treatment plant, the excess flow will be diverted to the environment as a plant bypass or combined sewer overflow (CSO).

However, if the wastewater can be diverted and stored in equalization basins or deep tunnel storage systems upstream of the plant, the stored flow can be pumped into the plant influent once the peak flow has subsided. Complete treatment (minimum secondary treatment standards) can then be provided to all influent flows.