You probably know that water when goes through the coatings of sand it causes almost complete stop of suspended colloid matters, as well as the change of water chemical elements. Based upon on that we come to the conclusion that the sand – sediment filter is actually a mechanical filter, which works based on a principle of mechanical detention of colloid suspended matters and roughly dispersed particles from the water, and that filtration itself is mainly done on the surface of the filtration layer. With this filtration we can hold just the particles that are larger than the pore between the sand granules.

Sand filter Automatic sand filter

     Nowadays we use sand filters under pressure in the activators for the preparation of the drinking water, technological water, as well as the water for cooling systems. The advantage of these filters is that the activity of the filtration material does not only mean the mechanical removing of suspended matters from the water, but the effect of filtration primarily depends of activity in the depth of filter material. Based upon that, we conclude that the filter works with the whole surface of filter compound. As the granules of the filtration material are smaller, so is their active surface going to be bigger and the effect of the filtration better. Because of the resistance in the very filter it cannot go above the certain limits.

     Reference: Sand filters can be used for removing the Fe and Mn hydroxides.