Multi-media water filter
Multi-media water filter system represents a significant improvement over single-media filters. This is primarily due primarily to improved filter bed action based on the innovative use and selection of filter media. Multi-media filtration permits delivery of high quality filtered water at much faster flow rates, as compared to a conventional sand filter. In a conventional sand filter, lighter and finer sand particles are found at the top of the filter bed, and coarser, heavier sand particles remain at the bottom after backwashing. Filtration takes place in the top few inches of the filter bed.
A multi-media filter is backwashed in the same manner as a sand filter, using reverse or upward flow of water through the filter bed. The various layers of media retain their stratification because each material has a different density.