Electrically driven sewage pumps are of the centrifugal type. Because of the solids, grit, etc., which the pump must handle, displacement-type pumps are not suitable.
A sewage lift station and a storm water lift station.
Bilge pumps.
A minimum of five minutes of pump capacity between high and low water levels.
The high water level should be maintained at least 3 inches below the invert of the influent pipe so as not to flood the subdrain piping and to also provide air circulation throughout the system. The low level should always be maintained at least 6 inches above the bottom.
Assign 2 FU for each gpm of pump discharge for the conversion.
A value of 1 gpm per 24 sq. ft. can be assigned for locations where the annual rate of rainfall is 4 inches per hour.
It is good practice to select a capacity 1-1/4 times the maximum inflow rate to provide an adequate factor of safety for periods when the calculated maximum flow will be exceeded by unusual storm conditions.