Modeling sewer network discharge into a treatment plant

Product(s): SewerGEMS, CivilStorm, SewerCAD
Version(s): All
Area: Modeling


How do you model discharge from a sewer network into a wastewater treatment plant?


Typically a treatment plant would be modeled with the Outfall node element. If there is a tailwater from the treatment plant that influences the upstream hydraulics, you would select the appropriate boundary type from the outfall properties. For example you can choose a user defined tailwater, or define a rating table. Typically a conservative assumption would be made for the outfall tailwater elevation. 

If you know the capacity of the treatment plant, you can model it using an elevation-flow rating curve on the outfall. This enables you to define the rise in water level as the flow into the treatment plant reaches or exceeds capacity. For example consider the below WWTP with a capacity of 1 MGD. Above 1 MGD, the water surface elevation begins to rise above the inlet pipe (100 ft), backing up into the upstream system.