I have wondered many times how a human would fare if the kidneys dumped urine into the start of the large intestines somewhere about the appendix instead of into a bladder to be sprayed out. I’m assuming water would be reabsorbed and slower to process out, primarily through sweat and evaporation from the lungs, and maybe diarrhea, though it may be that other waste products, such as salts or ureas may be absorbed into the large intestines instead of being ejected, though I have no idea if it would, or if it would be ejected as intended. Do we have any biologists here that could give insight on if combining both waste paths into one would be advisable?
You’re looking for a Cloaka
A cloaca still has facilities for urine to be dumped overboard, doesn’t it? My proposal is to recirculate it before dumping it overboard dry.
And what would you do with the water you’ve taken out in the drying process? Have seperate organs to seperate it (kidneys, colon) and a seperate set of organs to dump it out (pee)? That’s returning to the way we humans handle it. Or you need to stop flushing things with the water and stop eating food that contains it. Or your organism just accumulates water and explodes like a water balloon if it has no way to get out. It has to go somewhere if you ingest it.