When civilization developed human became aware of safe drinking water. From that time more water filtration demand increasing gradually. Boiling water is very oldest water filtration process. This methods of water purify process killed bacteria and also this phenomena is called later as Disinfection.
Some Water Treatment Process
Reverse osmosis water treatment process
Deionized water treatment process
Electrodialysis water treatment process
Evaporation water treatment process
Distillation water treatment process
Softening water treatment process
Activated carbon filter process
Very good remembrance of olden age filter methods. Any way Old is gold.