Weir overflow rate is flow per foot of weir length.
Weir Overflow Rate
Formula
Weir length = 3.1416 x Weir diameter x Number of clarifiers Weir overflow rate, gpd/ft = Flow, gpd / Weir length, ft
Inputs used
- Flow (MGD)
- Weir diameter (ft)
- Clarifiers in service (units)
- Or total weir length (overrides) (ft)
Worked example (White River WRRF, fictional)
- Weir length = 3.1416 x 86 x 4 = 1,081 ft
- WOR = 8,000,000 / 1,081 = 7,403 gpd/ft
Tips
- For a circular weir, length = pi x weir diameter (per side if double sided).
Results are estimates for operator use. Check units and inputs, and confirm decisions with plant data and procedures.