Basement bathroom question...

I am interested in renovating our basement for extra bedrooms and would like to add one or two bathrooms. Because of the way my sewer pipes go out of the house, I was wondering if this is even going to be possible or, if so, if I will need some type of pump system. Perhaps someone can tell me what they think by looking at the pic below.

Since water and s*** doesn't flow uphill, you will need an ejector pump system.

First I need some help here! WHAT is that 4in trap for??? Depending on what that is you might get a different answer.