An air gap is intended to prevent cross contamination between a source of contaminated water (grey, black, stagnate or drainage water) and your water softener or other clean appliance. As the softener supplies potable water to your household, it is essential that there is no chance for contamination.
I expect your reference to a 'lift station' to mean either a sump or holding tank which relies on a pump to discharge the contents. Merely running the softener discharge line directly into that 'lift station' would not itself provide a proper air gap. During a power interruption/pump failure, the tank could overfill and the softener discharge line could then be in direct contact with contaminated water.
Here is a site which supplies various types of air gap terminations.
http://airgap.com
Alternatively, if you need to drain into a floor drain, there is a air gap 'funnel' and clips which will connect to the floor grain grill:
http://www.tru-gap.com