What is the purpose of a basement bathroom ejector pump and how does it function in a residential plumbing system?

A basement bathroom ejector pump is used to pump wastewater from a basement bathroom up to the main sewer line. It functions by collecting the wastewater from the bathroom fixtures, such as toilets and sinks, and then pumping it through a pipe to a higher elevation where it can connect to the main sewer line. This helps prevent backups and allows for proper drainage in a basement where gravity alone may not be sufficient to remove wastewater.