Pressure sewer system

[bfehlberg]

I have a question. There is a project involving a pressure sewer system consisting of several small pump stations flowing to branches that connect then discharge into a gravity manhole. When figuring the TDH for each pump, should it be taken to the tie in for the next pump downstream or the final gravity manhole?

 

[Hammone]

It should be treated as a manifold system with each station being required to pump against whatever the maximum pressure that is in the common manifold.

 

[Marc]

You might want to call an Eone pump representative or check their web site at eone.com.  Eone manufactures grinder pumps for low pressure sewer systems.  They have a good design guide for designing multiple pump stations pumping within the same forcemain.  The guide has a graph which based on case studies will estimate the average number of pumps in use at one time for a given total number of pumps in the system.  You could then calculate the TDH for the system with the average number of pumps running at any given time.