I added a sink to my kitchen island. I had no idea venting would be such an issue. My question is, do I need to do the long/complicated configuration under my sink? I’m not sure what it is called. This one has an oval shaped drain/vent where both are connected to main sewer drain line and one of the lines branches off to the main vent. The other option is to use a mechanical vent of some sort. I live in Lake Bluff. I have no idea where to start. Locating the main vent won’t be easy as I waited til the last minute and the cabinets are installed. I don’t know where it is located.