I have a basement pit with a sewage ejector that serves a basement bath. I want to add a wet bar to the basement and the best method I have for plumbing it is to use an undercounter type basin and pump to pump the grey water to the pit where it will then be pumped by the sewage ejector. The question is how to add the line to the pit.

The pit has 2 inch waste and vent lines. the new line is 1 1/2 inch. My thought was to t into the vent line a few inches above the sump, thus the last 8 inches or so of the vent would be a wet vent. The only other option would be to drill a new hole in the lid and I am concerned as to how make that seal.

Thoughts are appreciated.