Berkefeld filter
Water filter made of diatomaceous earth (Kieselguhr) / From Wikipedia, the free encyclopedia
A Berkefeld filter[1] is a water filter made of diatomaceous earth (Kieselguhr). It was invented in Germany in 1891, and by 1922 was being marketed in the United Kingdom by the Berkefeld Filter Co.[2] Berkefeld was the name of the owner of the mine in Hanover, Germany, where the ceramic material was obtained.
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The Berkefeld is a good bacterial water filter used in microbiological laboratories, in homes and out in the field.[3][4]