How can we recycle human biological waste?

Question

How can we recycle human biological waste?

Answer 1

We compost it and recycle it as nitrogenous fertilizer for plants.

Answer 2

We don't need to, it recycles itself. If it goes back into the ground it decomoses and becomes nutrients that can be used for the growth of flora.

I suppose we could potentially harness the amounts of methane that human f***s give off, but using methane for energy isn't the best of things to be doing for the environment....