Advantages of Diatomaceous Earth Filters in Drinking Water Treatment

Diatomaceous earth (DE) is made up of the fossilized remains of diatoms which were  small, single-celled, hard-shelled algae that existed prehistorically. These fossils make DE a high-porosity substance, because the fossilized remains are actually exceptionally-small, hollow particles. DE started as deposits which covered the bottoms of the oceans and eventually became part of our soil. It is a soft, chalk-like substance that crumbles easily into a fine white powder. Much like pumice, DE feels quite abrasive. Although DE can be used as a mild abrasive, cat litter, a mechanical insecticide, a blood-clotting activator, a component in dynamite, and as a thermal insulator, its most common use is in diatomaceous earth filters used in swimming pools and water treatment facilities.

DE filters can be used to filter out very fine particles that would easily clog or pass through a paper filter. DE filters are most often used to filter water in swimming pools, but they can also be used in the treatment of drinking water and to filter other liquids such as beer, wine, syrups, and sugar. The technology started during WWII when the United States Army was in need of a portable drinking water treatment system. Since the material was lightweight, odorless, tasteless, and chemically-inert, that meant that it was safe for use with drinking water. After the war, people started building water treatment facilities using diatomaceous earth filters. There are still over 200 of these plants operating today, mostly in small municipalities.

DE filters are an excellent choice for small operations, because they don’t require chemical coagulation or the training of operators in the use of chemicals. In addition, they provide a filtering option that is much less expensive than other water treatment methods. DE filters are a superior choice for filtering well water under the influence of surface water because of their cyst-removal capabilities. The properties of diatomaceous earth filters have caused them to become one of the drinking water filtration methods approved for use by the Environmental Protection Agency (EPA).

Diatomaceous earth filters physically separate the suspended solids from liquids which other filtration products would allow to pass through. In a water supply, DE filters can successfully remove cysts, bacteria, algae, viruses, asbestos, turbidity, manganese, and iron. They cannot, however, remove color and other dissolved constituents. The EPA has established guidelines for the maximum concentration and types of particulates which can be in water to be filtered by DE filters. DE filters are available either as pressure filters or vacuum filters.