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Garofiltre vs Sand

Material surface

Sand Porous

GARO®Filtre Smooth, nonporous

Excavated form natural resources, sand offers the benefits of a low price, but it is a porous material with an irregular surface, which encourages bacterial growth within filters. This bacterial development also named biofilm clogs up the filter media and contributes to the creation of preferential paths, to pressure increase and in the end filter clogging.

Conversely, biological activity is inhibited in a GARO®filtre bed due to the totally smooth surface of the material.

This way GARO®filtre has shown its ability to resist to clogging, especially to algae in filter systems running with sea of surface water. Thus, filter efficiency remains constant during cycles, and backwashes are optimized in comparison with sand.

Composition

Sand 80% Silica minimum, no lime

GARO®Filtre 72% silica, and metallic hydroxides

GARO®filtre predominantly consists of green or brown glass granules. Colourants used to taint wine, champagne or beer bottles are the source of the media catalytic properties which enhances the filtration.

Pressure loss

Up to 50 % reduction.

The permeability through a GARO®filtre filtering pack is higher than with a sand filtering pack, thanks to a greater porosity.

Therefore the initial pressure loss induced by a GARO®filtre filtering pack is 40% lower compared to the initial pressure using sand with the same effective grain size.

The pressure loss during operation is also reduced since depth filtration occurs more than surface filtration, the corollary of this drop of pressure loss being less electric consumption for the pumping system and/or a more reliable pressure on irrigation networks (the electric consumption being more optimized if the pumping system is equipped with frequency converter).

Clogging

Sand
Very high caking of sand with limestone grip in case of highly mineralized water.
Very high caking of sand with algae grip.

GARO®Filtre
Limestone grip delayed.
Algae grip drastically reduced.

Backwash water consumption

Reduction up to 50% replacing the sand with GARO®filtre

Resistance to biological fouling leads to decreased clogging and thus less frequent backwashes which also means a reduction of backwash water consumption

Advantages are then:

  • Increased filtration efficiency
  • Drop in water consumption with more rapid backwash thanks to the smooth and non-porous surface
  • Resistance to biological or lime fouling which leads to decreased clogging and thus less frequent backwashes
  • Drop of pressure loss which means less electric consumption for the pumping system and/or a more reliable pressure on irrigation networks
  • Greater lifetime delaying the filter replacement operations
  • Environmentally friendly: more sustainable material than sand.