The goal of water treatment, usually from surface sources such as lakes, reservoirs, or rivers, is to remove contaminants and organisms through a combination of biological, chemical, and physical processes to make it safe for drinking. Some of these occur in the natural environment, whereas others occur in engineered and constructed water treatment plants. The engineered processes usually mimic or build on natural processes.

History of Water Treatment

Water-treatment concepts underlying those used today were developed in Europe during the 1700s. An outbreak of cholera in London was linked to a sewage-contaminated drinking water well in 1854. John Snow was credited with this finding. At the point in which the United States began using chlorine to disinfect drinking water (1908), Europe was also using chlorine but exploring the possibility of employing ozone to treat drinking water. The U.S. Public Health Service developed the first drinking-water regulations in...