The term media filter, as applied to water treatment, refers to the removal of suspended solids from water. In most cases, it is the last stage in the pretreatment of water for removal of un-dissolved impurities prior to treatment by Ion Exchange or by Reverse Osmosis. Coagulation, flocculation, and clarification precede filtration.
These Dual Media Filters used in water & wastewater treatment are either pressure or gravity filters depending upon the flow of water. Water is pumped through a pressure filter while water flows by gravity in a gravity filter. They employ granular media like sand, anthracite or activated carbon either alone or in combination as the filter media. Filters with special media are also used to remove iron and or manganese that may be present in some bore well waters.
Depending upon the application and requirements, media filter use variety of media to remove contaminants.