Why two buckets?
The two-bucket emergency toilet system provides a way to separate pee and poo during an emergency. Separating poo and pee reduces the odors, so your environment is much more pleasant. More importantly, keeping pee and poo separate makes disposal easier. Most of the volume of your waste is in urine, and urine is not toxic, at least not right away, so it is easier to safely dispose of pee into the environment. On the other hand, poo contains microorganisms that can cause dysentery, cholera and a whole host of dangerous diseases. For that reason, you need to keep poo separate and dispose of it carefully.