Black tank vent pipe location 2016 EB27

[Chrisy]

Looking into getting a composting toilet for our EB and need to vent it. Was hoping to tap into the black tank ventilation pipe. Not sure where it is in the bathroom or how to get to it.Can anybody help about this potential install?

[AnnArborBob]

In the corner of the toilet room just to the left of the toilet you will notice that a portion of the wall corner does not form a 90 degree angle but is rather at a diagonal. That small section of wall is held in place by a number of obvious screws. The black tank vent is behind that angled wall. FYI, the grey tank vent is on the other corner closest to the sink.