Adding a new drain line into a basement bathroom ejector pit
I'm finishing out part of my basement and need advice on how to add a new sink.
My question is tied to the drain line for the sink. The basement already has a finished bathroom w/ shower, stool, and sink which drains into an ejector pit which pumps the wastewater up to the main drain line exiting the house to the septic tank.
Here is my question: How do I bring the wastewater into the pit? It's sealed and mounted flush to the concrete basement floor. Do I need to come in through the side (Under the floor) or can I punch a new hole in the lid of the pit? I'm assuming the latter but I'd like to know the dos and don'ts before I start. Or, do I need to add a whole new pit? The kid(s) at the home improvement store(s) couldn't help out much...
Any relevant info / advise would be much appreciated!