Interesting fact from the History of Water Filters
The history of water treatment dates back to approximately the thirteenth century B.C. in Egypt. However, modern filtration began much later. John Gibb’s slow sand filter, built in 1804 in Scotland, was the first filter used for treating potable water in large quantities. Slow sand filters spread rapidly, with the first one in the United States built in Richmond, VA, in 1832. A set of slow sand filters adapted from English designs was built in 1870 in Poughkeepsie, NY, and is still in operation.
A few decades after the first slow sand filters were built in the U.S., the first rapid sand filters were installed. The advent of rapid sand filtration is linked to the discovery of coagulation. By adding certain chemicals (coagulants) to turbid water, the material in the water could be made to clump together and quickly settle out. Using coagulation, clear water for filtration could be produced from turbid, polluted streams.
By the end of the nineteenth century, there were ten times as many rapid sand filters in service as the slow sand type. Currently, slow sand filtration is only considered economical in unusual cases.
The diatomaceous earth filter was developed by the U.S. Army during WWII. They needed a filter that was easily transportable, lightweight, and able to produce pure drinking water. The diatomaceous earth filter is used in smaller systems, but is not commonly part of water treatment plants.