Assuming it is sewer ejection from the basement bathroom but it could just be a sump for the basement foundation drainage. Either way, you need to know about it and how it works because if the pump inside there fails, bad stuff will happen. If it is a sewage ejector, you need to be very careful about what goes into the basement toilet. Nothing but you know what an TP, no exceptions!
Your inspector and/or seller agent should have explained this to you.
I'm not saying this to be rude to anyone. It has a vent line coming off, with no obvious signs of being a radon line. Most radon lines have a detector on them, directly on them. This is exactly what I said, a sewage ejector. Don't make it more complicated than it is.
If you see some sort of red looping thermometer deal on any part of that line, yes, that's radon. If not, ignore anything to do with radon and it's a sewage ejector.
I've seen sewer ejector mechanisms and I really don't think that is it. I have never seen a sewer ejector mechanism that is not directly attached to the toilette. Here is my below near identical setup for both sump and radon.
I have seen many RADON setups and never even once seen one with any sort of detector or any other sign that it is RADON other than some simple writing on the pipe.
That 2" pipe is too small to be for radon mitigation. It is more likely a vent pipe. A radon pipe should have a U-tube manometer to show that the fan is actually pulling a suction. It is NOT a radon detector.
There is a rubber plug on the top where the cord comes through. Pull it up, turn on a faucet in the bathroom and see if either the pump kicks on or you hear water coming in. If so, it's a sewage ejector.
That 2" pipe is too small to be for radon mitigation. It is more likely a vent pipe. A radon pipe should have a U-tube manometer to show that the fan is actually pulling a suction. It is NOT a radon detector.
All a radon pipe is is a vent pipe. It vents gasses from below your house above it to the atmosphere. While you could have a fan it is not required. Mine does not have a fan.
it is a sewage or sump pump. there is a check valve on outlet. that is to stop water that has been pumped out from coming back into pit.the bigger pipe is a vent to keep pump from vapor lock.
Does your main drain from upstairs go out above the basement floor. It probably does. The bathroom in the basement
will drain into the black pit and then get pumped out to the main drain. Just like Justin said.