Pump Station Sizing

[PBW2]

This is a continuation of an earlier thread but with a little more information. Basically, we've got a situation with the design of a new pump station that will serve a new development with gravity sewer and that will also be handling discharge from other pump stations. These other existing pump stations were designed for the ultimate build-out (hasn't happened and may not happen) and therefore the pumps ended up being oversized.

For example we have one downstream existing pump station that is pumping at 200 gpm. However, the required pump rate based on the sewer loading to the station is 80 gpm (the neighborhood is built out). Conservatively we'd design our new pump station for the full 200 gpm of pumped discharge into the staion + the sewer load from the new neighborhood gravity sewer. By doing this we are going to oversize the new pump and may have to install a new FM instead of using an existing FM. A couple of ideas:

1. Replace existing oversized pump at the existing pump station to reduce the discharge
2. Determine maximum volume coming from downstream pump station and account for it in the new wetwell/pump design.

Of course, we'll design the new pump station so that it can be modified to handle the ultimate build-out. Ideas/comments welcome.

 

[bimr]

It is also important to maintain the velocity in the force main to prevent solids from settling out.