Sand filters are used to remove suspended solids from water and wastewater. Because they have one layer of filter media, sand filters remove only relatively large solids (normally in the range of 40 micron and larger). The effective size of each granule of sand typically varies from 0.35mm – 1.2mm. Larger granules yield coarser filtration. Finer granules yield finer filtration.
Sand filters are typically used for:
Irrigation water
Storm water
Cooling water
Swimming pool water
Water in fountains and other water features
Removing suspended solids smaller than 40 microns requires filters with either two or three layers of filter media. These are referred to as dual-media filters or multi-media filters. When sized properly and with the correct configuration of filter media, these filters can remove suspended solids as small as 5 micron.