I have no idea? It's your story not mine.
Human poo is 75% water. Yes; 75% water! So there is really very little solids. And what is there is organic water soluble material.
A study of what really is in human poo.It's really easy to do your own study. Fine yourself a big dog pile and put it in a mason jar with a sealed lid and fill it to the top with water. Leave it sit for a month and see what happens at the end of a month. Sure, it may settle out but it's not going to turn into "cement" like I have heard on here many times. :R