Gas seal for wastewater?

[JKM9]

I have more than once seen pumps damaged when, for whatever reason, the seal water system fails at a wastewater facility. I am curious about the viability of nitrogen gas pump seals in that environment. Since such a system can send an alarm well before the nitrogen supply actually runs out, it would seem to solve this problem. But invariably I see water seal systems.
Does anyone have experience with gas seals in this application?
JKM9

 

[longeron]

I'm spec'ing one out now for a vertical sump pump. Sure. There may be some issues depending upon the application.

Remember that if the N2 source is a bottle that you can have the same situation arise- the bottle pressure drops below the pressure needed for the seal, and oops....