Brings a New Meaning To The Term 'Eat Sh...T'
 

Hmm..where to begin? The movie 'Caterpillar' where victims are stitched together in a row, the Frank Herbert Dune series books where stilsuits capture everything emitted and recycle for use, fecal replacement therapy pills which have proven beneficial, same as dogs eating each others flora, same as my cat licking the dogs behind, our appendix which stores beneficial bacteria same as 1849 Boudin Bakery stores their yeast starter, that Humans Have Ten Times More Bacteria Than Human Cells, etc..

Stillsuits in Dune only captured moisture for recycling.

Being a kiwi boy I take offense at that. Why couldn't they make a Marmite look-a-like instead.

The reason all life has to eat, is to get the energy for the cells in the body to grow and reproduce. That takes energy. Crap has most of the nutrition removed by the organism that produced it. Certainly some things pass through undigested like corn often does. Just chew the corn or grind it into corn flower and not much will pass through.

Some culture eat dirt for the minerals, but a decent balanced meal will negate needed to do that.

I have no idea how much nutrition is left in the average turd, but it ain't much. Some of it can be used by plants and microorganisms, and we have all seen flies on a pile of poo. I just can't see that there is enough nutrition in poop to be worth eating no matter how processed it is.

Urine is mostly water so removing the waste products and getting the water back out is fairly straightforward.