Large Scale - Sand and Multimedia Filters
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 40-100 microns). 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
- Cooling water
- Swimming pool water
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.
Units are skid-mounted, workshop assembled and wired, hydro-tested, and delivered ready for installation. Piping, valves, pressure gauges and accessories are included with filter systems. Solar power, media air scour, and rinse cycle are available as options. Filter systems are engineered to require little maintenance. A separate source of water supply or a pump for backwash are seldom needed.
Dual and Multi-media filters are typically used for:
- Industrial process water
- Waste water
- Potable (drinking) water
The size of each filter, the number of filters required, and the type of filter media used depend upon:
- how small a solid needs to be removed,
- how dirty the water is,
- how the water will be used once it is filtered,
- and the source of backwash water needed to clean the filters.
Size of Solids to be Removed: The smaller the solid to be removed, the slower the water must pass through the media and the finer the granule of media must be. Very often the end user doesn’t know how small a solid must be removed. In those situations, how the filtered water will be used will determine how small a solid should be removed.
Concentration of Suspended Solids: The higher the concentration of suspended solids, the larger the diameter of the filter needs to be.
Source of Backwash Water: Backwash water is used to clean the filters and flush out the suspended solids that have been trapped in the media bed. Water for backwashing can come either from the filters themselves or from an external source of clean water (such as a domestic water line or a storage tank).
Filtec - Large-scale Sand Filtration