Superman throws Zod to a precipice and we never see him again.
He's not even mentioned in any way.
We don't see him in jail or at the very least in a Daily Planet headline for one second.
Not even in the Phantom Zone or anything filmmakers use to do in order to inform us the villiain's alive.
But more definitive proof: they already HAD a scene showing us Zod was alive and being sent to jail and they decided NOT to put that into the film, not even a couple of seconds so we could know. I could understand they didn't want to make a special scene just to show that, okay (although even so they could have had another ways to mention Zod's fate; the headline or a short verbal mentioning) but the already had the scene and they decided not to put it into the movie, which as if for the filmmakers' intentions, shows that they prefered us to think Superman just got rid of the super-villiains by throwing them into a precipice where they... just vanished into death or died.
Donner had the intention to show Superman didn't kill him, but as we know, it was Lester who had the final cut and it's there for us to see. Having multiple options they had the surviving Zod out of the movie.