When the filtering layer begins to clog need cleaning it, which happens every 4 to 6 weeks. The cleaning is manual and involves removing the first layer of sand, sand washing in separate tubs and in reconstruction of filter bed. Quick filters are the most used, particularly in combination with other treatments such as clarification (surface waters) and the removal of iron and manganese (deep waters), and can deal with an input flow rate 40 times higher than that of lens filters (survival water purification systems).
Quick filters are identical to those lenses; only varies the thickness of material forming the filter bed and the mattress filtering, in order to make faster the speed of filtration, equal to 5-10 m / hour. In this case the filtration is mechanical. For quick filters as a rule are used leach monolayer (single media) consisting of quartz sand (50-80 cm thick) supported by a mattress filter, or a drainage layer, consisting of coarser material (such as gravel) the thickness.
The filtration is carried out by passing the waters (from rivers or lakes) through various types of implants removal of organic and inorganic material. The removal methods used can be physical, chemical-physical and biological function of type of substances to be eliminated from waters entering the plant.
The filtering layer resting on a draining bottom, which has the function of: surface filters: filtration takes place through filter cloths which prevent the passage from the materials above the size of blind holes (not es.tessuto tissue; in this case the particles are retained on the surface of filter media forming a layer of material that retains the subsequent particles.
Physical and chemical treatments normal and driven: they are divided into several phases and eliminate non-settleable suspended solids (flocculation) and correct the chemical characteristics of waters by eliminating the dissolved substances that are incompatible with the use to which the waters is bound (softening, stabilization, removal of iron, manganese, desilication, fluoridation and defluoration, aeration).
Treatments: also divided into several phases, improve the organoleptic characteristics of waters (adsorption on activated carbon) and lower the content of dissolved solids (demineralization). The interventions of this type are provided, when necessary, upstream of treatment processes of filtration real, and allow the removal of materials and substances which by their nature and size are likely to damage the equipment and compromise the efficiency of subsequent treatment stages.
The filters are formed from cylindrical vessels made of reinforced concrete on the bottom of which special shelves, provided with an adequate number of holes, support the filtering mass. The filter bed consists of fine sand / fine or other material minute. The filter bed is supported by an underlying layer of material, also the filter, formed by a layer of coarse gravel and the overlying layers of gravel gradually finer (mattress draining).
The sedimentation is carried out in special tanks, called decanters, within which the waters moves in a laminar flow as possible for a time sufficient to allow the sedimentation of heavier particles. Decanters flow or vertical upward flow are generally circular section. Inse tanks the entrance of waters can be centrally from above; in this case waters, to be able to escape from the tank itself is forced along a tortuous path; in fact must first move vertically downwards in order to pass beneath a baffle concentric, said fireplace, subsequently, passed over the obstacle fireplace, must rise and exceed a weir located along the perimeter of tub.
Quick filters are identical to those lenses; only varies the thickness of material forming the filter bed and the mattress filtering, in order to make faster the speed of filtration, equal to 5-10 m / hour. In this case the filtration is mechanical. For quick filters as a rule are used leach monolayer (single media) consisting of quartz sand (50-80 cm thick) supported by a mattress filter, or a drainage layer, consisting of coarser material (such as gravel) the thickness.
The filtration is carried out by passing the waters (from rivers or lakes) through various types of implants removal of organic and inorganic material. The removal methods used can be physical, chemical-physical and biological function of type of substances to be eliminated from waters entering the plant.
The filtering layer resting on a draining bottom, which has the function of: surface filters: filtration takes place through filter cloths which prevent the passage from the materials above the size of blind holes (not es.tessuto tissue; in this case the particles are retained on the surface of filter media forming a layer of material that retains the subsequent particles.
Physical and chemical treatments normal and driven: they are divided into several phases and eliminate non-settleable suspended solids (flocculation) and correct the chemical characteristics of waters by eliminating the dissolved substances that are incompatible with the use to which the waters is bound (softening, stabilization, removal of iron, manganese, desilication, fluoridation and defluoration, aeration).
Treatments: also divided into several phases, improve the organoleptic characteristics of waters (adsorption on activated carbon) and lower the content of dissolved solids (demineralization). The interventions of this type are provided, when necessary, upstream of treatment processes of filtration real, and allow the removal of materials and substances which by their nature and size are likely to damage the equipment and compromise the efficiency of subsequent treatment stages.
The filters are formed from cylindrical vessels made of reinforced concrete on the bottom of which special shelves, provided with an adequate number of holes, support the filtering mass. The filter bed consists of fine sand / fine or other material minute. The filter bed is supported by an underlying layer of material, also the filter, formed by a layer of coarse gravel and the overlying layers of gravel gradually finer (mattress draining).
The sedimentation is carried out in special tanks, called decanters, within which the waters moves in a laminar flow as possible for a time sufficient to allow the sedimentation of heavier particles. Decanters flow or vertical upward flow are generally circular section. Inse tanks the entrance of waters can be centrally from above; in this case waters, to be able to escape from the tank itself is forced along a tortuous path; in fact must first move vertically downwards in order to pass beneath a baffle concentric, said fireplace, subsequently, passed over the obstacle fireplace, must rise and exceed a weir located along the perimeter of tub.
