2000 B.C - The first recorded (The Susruta Samhita, Sanskrit writing) water purification began with the Egyptians. It is said that impure water should be boiled over a fire, heated in the sun, have a hot iron dipped into it or purified by filtration through sand and course gravel.
A major step in the development of desalination technologies came in the 1940s during World War II when various m