Freshwater sources like rivers provide raw water that contains a lot of pollutants that make it unsafe; it must be eliminated. For this purpose, the waters will undergo a number of treatments needed to make it drinkable. The screening is the first step in a treatment process, which is to retain any large debris such as sticks, plastic bottles and cans (portable water purifiers for survival). To do this, it sets up a grid system, the spacing is about 50 mm. Once the gates are clogged with waste, a scraper rises along grids and knocked down the waste into a skip which, once full, is obviously to landfill.
In case where it is necessary to perform a removal of coarse solids thrust not settleable and suspended solids do not sediment is expected next to grilling also a sieving (or screening) or a microstacciatura. This type of intervention is normally alternative to primary sedimentation and also is also used for the removal of algae and plankton. The sieve consists of rotating cylinder (drum or noria) stainless steel horizontal axis, closed at its ends and partially immersed in a tank, on which is mounted a metal mesh also made of stainless material.
For a conventional filtration, the most common materials are sand and anthracite. The sand is used alone as a monolayer or associated with the bilayer in anthracite filters. Biological filtration media (iron removal, manganese removal, nitrification, denitrification) are sand and granular activated carbon. Waters purification (or purification) is the removal of contaminants from raw waters to get waters that is fit for normal domestic consumption or for irrigation of fields and also for industrial uses (eg. For use by establishments for food). With the gradual depletion of natural sources of drinking waters (deep waters), is increasingly resorting to surface waters (seas, rivers, lakes and dams).
After gathering the different small particles of much larger, we must now settle this. In a still body of waters, the heavier suspended particles than waters are subject to their apparent weight (actual weight less buoyancy). They are falling slowly to build up on the bottom: the settling. Their fall velocity obeys Stokes' law:
Besides the possibility to retain materials particularly small, as sieving has the advantage, compared to grilling, to retain all the material that has at least one dimension greater than the measurement step of network. The main drawback of sieving however, is the ease with which occur clogging and the need for frequent maintenance and cleaning. The sieving can applied only in case of waters with a low concentration of suspended solids.
However, the fact that the waters is by nature a solvent makes it somewhat problematic the effective elimination of many unwanted substances. The waters is put into a tank head from which it originated the system of waters supply - drinking. The interventions of this type are provided, when necessary, upstream of treatment processes of waters purification 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 first filtration principles were inspired by the natural filtering the waters passing through the different layers of Earth, before reaching the "underground tanks." Unfortunately, this process is far too slow to handle large amounts of waters. Note however that the thus filtered waters is often of excellent quality.
This law is valid for strictly spherical particles immersed in a liquid at rest and at constant temperature where the downward motion is not influenced neither by the presence of other particles or from the container walls. 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.
In case where it is necessary to perform a removal of coarse solids thrust not settleable and suspended solids do not sediment is expected next to grilling also a sieving (or screening) or a microstacciatura. This type of intervention is normally alternative to primary sedimentation and also is also used for the removal of algae and plankton. The sieve consists of rotating cylinder (drum or noria) stainless steel horizontal axis, closed at its ends and partially immersed in a tank, on which is mounted a metal mesh also made of stainless material.
For a conventional filtration, the most common materials are sand and anthracite. The sand is used alone as a monolayer or associated with the bilayer in anthracite filters. Biological filtration media (iron removal, manganese removal, nitrification, denitrification) are sand and granular activated carbon. Waters purification (or purification) is the removal of contaminants from raw waters to get waters that is fit for normal domestic consumption or for irrigation of fields and also for industrial uses (eg. For use by establishments for food). With the gradual depletion of natural sources of drinking waters (deep waters), is increasingly resorting to surface waters (seas, rivers, lakes and dams).
After gathering the different small particles of much larger, we must now settle this. In a still body of waters, the heavier suspended particles than waters are subject to their apparent weight (actual weight less buoyancy). They are falling slowly to build up on the bottom: the settling. Their fall velocity obeys Stokes' law:
Besides the possibility to retain materials particularly small, as sieving has the advantage, compared to grilling, to retain all the material that has at least one dimension greater than the measurement step of network. The main drawback of sieving however, is the ease with which occur clogging and the need for frequent maintenance and cleaning. The sieving can applied only in case of waters with a low concentration of suspended solids.
However, the fact that the waters is by nature a solvent makes it somewhat problematic the effective elimination of many unwanted substances. The waters is put into a tank head from which it originated the system of waters supply - drinking. The interventions of this type are provided, when necessary, upstream of treatment processes of waters purification 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 first filtration principles were inspired by the natural filtering the waters passing through the different layers of Earth, before reaching the "underground tanks." Unfortunately, this process is far too slow to handle large amounts of waters. Note however that the thus filtered waters is often of excellent quality.
This law is valid for strictly spherical particles immersed in a liquid at rest and at constant temperature where the downward motion is not influenced neither by the presence of other particles or from the container walls. 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.
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