Rapid sand filters can be constructed as pressure filters. They are used for water purification purposes and consist of closed vessels containing beds of sand or of other granular material through which water is forced under pressure. These filters are frequently used in certain industrial situations, and a number have been installed for public water supplies. As their initial cost may be high, especially when their component parts have to be imported, their principal use is in industrialised countries.
References
Glossary Term Name
Legacy NID
5192
Legacy VID
16851