We bought a home that already had a sewage pump installed in the basement with three drains already installed in the concrete floor that leads to this pump's tank. One was for a toilet (which is covered), another is for a sink (which at present is in use) and the third is a drain pipe (rubber cover) about 4.0 inches in diameter and sticks 3 inches out of the concrete floor. It is the last one that we want to use as the drain to a shower.

The third pipe leads directly into the sewage pump tank that is located within the basement floor.

What is the best way of installing a self made shower base for the 4.0 inch drain? Because a trap is needed, how high must the base be built off the basement floor? I would like the shower base to be as close as possible to the floor but I perfer not to dig up the concrete floor.