Outhouse idea

I was at a park in Findlay, Ohio recently and stumbled onto this outhouse idea (fortunately I didn't stumble into it). We were at the Riverbend Recreation Area just east of Findlay, and they had this outhouse pictured below. It appears they've just put a concrete slab down over their pit (or a septic tank), and put a toilet seat on top of it; along with a urinal that drains into it; as well as a vent pipe; and there's a skylight for light. It didn't have any running water or electricity.

I certainly don't know much about this sort of thing, but if we could just build something like this out back of the church where our septic tank is that would solve our restroom problem for the pavilion and playground. People can reserve the inside restrooms if they're having a party, but for people who just stop by on an everyday basis there isn't anything. So... maybe this would be a lower-cost alternative. I don't know. Hopefully I can find someone who does know.

These are the pics...