Sewage-ejector systems — Sewage-ejector tank-and-pump systems are designed to pump sewage upward to the sewer or septic tank line. They’re like small septic tanks in that they hold waste temporarily. These come in both aboveground (freestanding) and belowground versions. Aboveground models sit on the floor, so installing one requires no excavation. The toilet is positioned on top of an enclosed tank and pump unit. Your sink and bathtub or shower can also drain into this tank.
Jensen Flotec FP400C 4/10 HP Sewer Pump System (Ejector Sewage 11/32)
If you need to add a sewer pump in the basement it is usually because your sewer line level at home is below rather than above the main sewer line from the street, that means that the water cannot fall into the sewer line from above as it would naturally so you need a pump to push the water from the low point to the sewer line in the street. http://alldonecompany.com/adding-sewer-pump-in-basement-for-new-bathroom/