Determining new PS capacity w/ consideration of additional discharge from an existing PS

[PBW2]

We were tasked to design a new pump station that will discharge into an existing (common) 4” forcemain that runs past the new PS site. I have checked the existing pump station upstream and with our new station running it appears that the existing pump station will be locked out. We’re not a big fan of common forcemains so our solution is to modify the existing FM to dump into our new receiving manhole. We'll then connect a new FM from our new station to the existing FM. We'll then size the new pump station to pump the existing pumps design discharge + 1.8 x calculated new sewer inflow. In addition we’ll look at 2.5 x new area inflow with no additional flow from the existing pump station. I would be interested to hear others opinions/remarks.

 

[dicksewerrat]

Do both pump stations have the same owner?

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[PBW2]

Yes, they're both owned by the same municipality.

 

[dicksewerrat]

Then i would do what you suggest. Size the new wet well to hold existing and future. Design the pump/pumps so you can use the guide rails, etc for larger pumps in the future. May require that future pumps to be same pump manufacturer. Also need to look at the power supply and control panel.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[bimr]

I assume that you are referring to peaking factors. The peaking factors that you appear to be using seem to be on the low side. Peaking factor vary with population being larger for small population and smaller for larger populations.

 

[PBW2]

Thanks Dick!

Bimr - For this project the minimum peaking factor 2.5 is dictated by the state regulatory agency. I was just wondering how others might be handling flows pumped from another pumping station into a new station coupled with the flow from the new area.

 

[bimr]

If that is all you are after, I would agree that a single pump station connected to a single forcemain is the best approach.