Waterless urinals are an option too. You don't flush them.
The waste just runs through a trap with a little oil =20
Sounds goofy but we've installed a number of these at work and they are doi= ng fine.
The biggest problem is that some clown comes along and dumps a mop bucket, = not knowing what kind of urinal it is. That washes the trap dry, and then = sewer smells get out. But in your own mancave you can control that.
There's another variation we saw in German train stations. Weird looking, = but effective for large crowds. Europe has very heavy passenger train usag= e. Basically, the wall has a sheet of water continuously flowing down, and= you eliminate into the stream. here's a photo
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