Water Filtration

Abstract The most universally used particulate removal technology in drinking water treatment is filtration. Filtration is the process of removing particulate matter or suspended solids from water by passing the water through a porous medium, permeable fabric, or membrane. The commonly available water filtration processes are rapid gravity filtration, slow sand filtration, diatomaceous earth filtration, membrane filtration, cartridge filtration, and special types of filtration. A variety of modes of operation are available such as downflow, up‐flow, multiple layer, biflow, radial flow, semicontinuous (moving bridge), continuous (media recycle), variable voidage, and pebble matrix. All of these have the same basic objectives: to produce a filtrate that is clear and contains very few particles and to provide a medium‐cleaning process so that operation may be continued with the same medium or by replacing the old medium. The same principles of filtration apply to all these processes.