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.
Filtration is a treatment used to remove suspended solids from the waters not sediment. Treatment consists in passing the raw waters through a filter medium (bed / filter layer or filter cloth). In case of filter layer, the filter material can be made from quartz sand, anthracite or activated charcoal. During filtration the filtered solids gradually begin to clog the filtering layer resulting in an increase of load losses, which is increased to overcome the supply pressure. Exceeded the maximum value of said pressure must be made to interruption of flow and to cleaning of filter medium.
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.
ants: the most used today are the polyelectrolytes. The agitation speed should be neither too low to prevent sedimentation of flakes, or too high to avoid breakage of flake. The slow agitation is achieved by use of mechanical mixers (dynamic system) or by placing a series of baffles in tank (static system).
The flocculation basins have a rectangular shape and can be: Staged: where to achieve greater efficiency, the tank is divided into several zones in series in which the agitation is gradually decreasing. Channels: are horizontal flow, where the pool is subdivided by transverse partitions to form a channel whose width is gradually increased so as to obtain a flow velocity gradually decreasing.
The 'sodium aluminate is very expensive and is also used in treatment of lime-soda softening species in case of high hardness and magnesium. In some waters, even with a strong dose of coagulant, are unable to develop a staple of suitable density. Inse cases, adjuvants are added to waters coagulation to promote the densification of micro-flakes.
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.
Filtration is a treatment used to remove suspended solids from the waters not sediment. Treatment consists in passing the raw waters through a filter medium (bed / filter layer or filter cloth). In case of filter layer, the filter material can be made from quartz sand, anthracite or activated charcoal. During filtration the filtered solids gradually begin to clog the filtering layer resulting in an increase of load losses, which is increased to overcome the supply pressure. Exceeded the maximum value of said pressure must be made to interruption of flow and to cleaning of filter medium.
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.
ants: the most used today are the polyelectrolytes. The agitation speed should be neither too low to prevent sedimentation of flakes, or too high to avoid breakage of flake. The slow agitation is achieved by use of mechanical mixers (dynamic system) or by placing a series of baffles in tank (static system).
The flocculation basins have a rectangular shape and can be: Staged: where to achieve greater efficiency, the tank is divided into several zones in series in which the agitation is gradually decreasing. Channels: are horizontal flow, where the pool is subdivided by transverse partitions to form a channel whose width is gradually increased so as to obtain a flow velocity gradually decreasing.
The 'sodium aluminate is very expensive and is also used in treatment of lime-soda softening species in case of high hardness and magnesium. In some waters, even with a strong dose of coagulant, are unable to develop a staple of suitable density. Inse cases, adjuvants are added to waters coagulation to promote the densification of micro-flakes.
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.
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