Purifying Process for Black Water and Gray Water?

Question

What are the differences between the purifying proccesses for black water (from the toilet) and grey water (from the shower etc)?

Why would shower water be purified differently if a woman's menstrual cycle (composed of potentially dangerous bodily fluids) is mixed in like it would be in toilet water?

Thank you for your explanations :)

Answer 1

*  Actualloy, these waste waters generally go to the same place - the treatment plant - where they are biodegraded by bacterial action.  

Some folks on septic systems separate the grey water so as to avoid overtaxing the system.  With no solids to speak of, and only a small concentration of contaminants, the trickle filtration through the percolation process is sufficient to render the grtey water safe.

The solids must go through a more rigorous treatment to become stabilized.  Either aerobically or anaerobically.

Answer 2

In the city it all goes to the treatment plant.

Some people in rural areas have two ( I have three ) for different types of sewage. The toilet water goes to a septic tank. The gray water is used for irrigating and goes to a separate tank. And the water softener discharge goes to a mini dry well due to it's salt content.

A septic tank eats most anything and produces heat. When I was young it was fashionable to kill a chicken and flush the blood and organs down the toilet to get the bacteria going in a septic tank. There are now pills that do a better job.