Automatic Backwash Bypass Filtration Shallow Sand Filter:

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. All filters have a maximum concentration of suspended solids that can be managed without compromising filter performance.

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).
If backwash water comes from the filter system, there must be more than one filter in the system. Filters are backwashed one-at-a-time. During the backwash cycle, a portion of filtered water exiting the other filter(s) in the system is used to clean the dirty filter. During these periods (which typically last for several minutes per filter), the amount of filtered effluent flowing downstream of the filter is reduced by the amount of water required for backwashing.

In cases where this temporary reduction in flow is acceptable, there will be two or more filters in the system.

If no decrease in the flow of filtered water can be accepted, then water for backwashing is supplied from an external source or the pump supplying water to the filters must be able to increase its output when backwashing is required.

Units are skid-mounted, and factory assembled, wired and tested. They are delivered ready for installation. Piping, valves, pressure gauges, filter media and accessories are included with the filter system.

Design Features of Sand and Multi-media Filters: Solar power, media air scour, and rinse cycle are available as options. Filter capacities are from 5 GPM to 14 MGD. Chemical injection packages, settling tanks, clarifiers, and disinfection units are also available.

O 8 in. To 12 ft. Diameter vessels
O Automatic or manual operation
O All steel construction (mild steel, 304 and 316 stainless steel)
O Stainless steel vessel internals
O ASME code or non-code vessels
O Hydraulic, pneumatic or electric valves
O High pressure and temperature options
O Class 1, Div. 1 or 2 preparation