Sand filters

BUPOLSA sand filters are made of glass fibre reinforced polyester (GRP) and are the most commonly used elements for filtering water with low or medium loads of pollutants that require particle retention. The particles in suspension that the water carries are retained during their passage through a filtering bed of sand. Once the filter has been charged with impurities, reaching a preset pressure drop, it can be regenerated by backwashing. The quality of the filtration depends on several parameters, among others, the shape of the filter, height of the filter bed, characteristics and granulometry of the filter mass, speed of filtration, etc.

The dirty water enters the upper part of the filter and descends through the sand filter bed. The filtration is carried out by absorbing the solid particles along the filter bed, which can be sand, active carbon, flint, anthracite, etc. When the water reaches the bottom it is collected in an outlet manifold. The sand filter bed is retained inside the filter thanks to crepines or filter arms with small water passage grooves. The solid particles are retained in the sand bed.