How to connect new forcemain into existing? 2

[NCCaryME]

Our facility was designed with sanitary sewer lines from various points which gravity-feed into a common lift station, and then pumped into a new forcemain that eventually feeds into the municipal system. A new building is being erected on site which will have washrooms, however this new building is remote compared to the existing lift station. The state agency will not allow us to install a septic field, due to the fact that we already have a lift station and access to the municipal system via our forcemain.

I already know that we will need to install a lift station at the new building and pump to some location. Due to the facility layout, I would prefer to connect directly to our existing forcemain rather than feed into the main lift station. What are the typical requirements for connecting a small forcemain to a larger one? Is this allowable, and if so, what are the concerns? I assume I would need check valves on both lines, but I don't know how to deal with the two lift stations competing with each other if they are running at the same time.

Any information is greatly appreciated.

 

[Maury]

You could interconnect the controls so that both stations cannot pump at the same time, if the wet well capacities and required pumping times permit. Depending on the head conditions, finding pumps that will operate under stand alone conditions and with both stations operating may be difficult to impossible. Check valves aren't a big problem since all pumps have them out of necessity.

Runningg the new force main to a discharge point on the sewer system might be preferable.

 

[bimr]

Ditto Maury's comments.