My basement was roughed in for a bathroom. I finshed the bathroom a few years ago and now I want to add a wet bar. Out of the concrete floor are two 2" pvc pipes 1 is going straight up to the ceiling (I assume that is the vent pipe) and the other comes up about 2 feet and connects to the vent pipe. ( that is where I tapped in for the drain in the bathroom)

I need to know if I can drain the wet bar to the vent pipe going (1st pipe) cause I have no room to attach a fitting to the second pipe. I don't know if both drain to the injector pump.

Also for the wet bar sink do I need a vent pipe attached? Cause where the sink is there is no way I can run another pvc pipe to attach to the existing vent.