The channel in correspondence of grid widens in such a way that the speed of waters downstream of grid, given footprint of bars, is maintained next to one that occurs in upstream portion. The speed of waters passing through the grid must be sufficient to prevent the sedimentation of solids upstream of same but not too high in order not to increase the load losses (portable water purifiers for survival).
Rolled sand is a natural sand, sifted after washing and drying. Unlike the sharp sand, it has rounded grains, and exists in a grain size range, that is to say of dimension sand, smaller. Anthracite, carbon-based material obtained by calcination of plant material such as wood or peat. It is in form of hard and angular grains. Its actual density is of order of 1.45 to 1.75;
It is also accelerated by regulating a pH optimum to obtain best possible precipitation of all the metal hydroxides which have just appeared with the coagulation reaction. Is used calcium hydroxide Ca (OH) 2, also known as milk of lime or slaked lime, and sulfuric acid H2SO4 to regulate the pH optimum of between 8.45 and 8.9.
These sources of supply, due to specific characteristics of waters and / or the degree of pollution, must be subjected to cycles of treatments of purification necessary to modify the characteristics and improve its quality. Often, this happens even for the deep waters with a high content of organic substances and a high microbial contamination, especially if they are present faecal bacteria (eg. Coliforms).
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.
It is therefore necessary to use dynamic settling through which one can act on the trajectory for continuously separating particles of different size and density. This type of separator is also called "lamella clarifier". It significantly improves the speed of settling. Decanters are currently used in small installations, horizontal separators; for very large installations, we prefer decanters powered by this principle but with a functioning a little more optimized. After this very important step in settling, it remains to remove even smaller particles by filtration.
The functionality of desanding is linked to ability to allow the sedimentation of inert materials having a diameter exceeding certain values, indicates that the practice in 0.2-0.5 mm. These materials may in fact create problems for subsequent treatments as they can clog pipes and channels, and abrasive electro-mechanical equipment (pumps). With Desanding you reach the goal of eliminating 65-70% of suspended solids and to improve waters quality to be sent to following treatments. In these conditions the speed of sedimentation of particles is adjusted in a first approximation by Stokes law.
Now filters are used batteries according to treatment suffered by the waters before you get to this stage. For a conventional waters treatment plant, various treatments are: rapid mixing with a coagulant, flocculation, sedimentation. Filtration materials encountered in treatment of drinking waters are numerous.
Rolled sand is a natural sand, sifted after washing and drying. Unlike the sharp sand, it has rounded grains, and exists in a grain size range, that is to say of dimension sand, smaller. Anthracite, carbon-based material obtained by calcination of plant material such as wood or peat. It is in form of hard and angular grains. Its actual density is of order of 1.45 to 1.75;
It is also accelerated by regulating a pH optimum to obtain best possible precipitation of all the metal hydroxides which have just appeared with the coagulation reaction. Is used calcium hydroxide Ca (OH) 2, also known as milk of lime or slaked lime, and sulfuric acid H2SO4 to regulate the pH optimum of between 8.45 and 8.9.
These sources of supply, due to specific characteristics of waters and / or the degree of pollution, must be subjected to cycles of treatments of purification necessary to modify the characteristics and improve its quality. Often, this happens even for the deep waters with a high content of organic substances and a high microbial contamination, especially if they are present faecal bacteria (eg. Coliforms).
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.
It is therefore necessary to use dynamic settling through which one can act on the trajectory for continuously separating particles of different size and density. This type of separator is also called "lamella clarifier". It significantly improves the speed of settling. Decanters are currently used in small installations, horizontal separators; for very large installations, we prefer decanters powered by this principle but with a functioning a little more optimized. After this very important step in settling, it remains to remove even smaller particles by filtration.
The functionality of desanding is linked to ability to allow the sedimentation of inert materials having a diameter exceeding certain values, indicates that the practice in 0.2-0.5 mm. These materials may in fact create problems for subsequent treatments as they can clog pipes and channels, and abrasive electro-mechanical equipment (pumps). With Desanding you reach the goal of eliminating 65-70% of suspended solids and to improve waters quality to be sent to following treatments. In these conditions the speed of sedimentation of particles is adjusted in a first approximation by Stokes law.
Now filters are used batteries according to treatment suffered by the waters before you get to this stage. For a conventional waters treatment plant, various treatments are: rapid mixing with a coagulant, flocculation, sedimentation. Filtration materials encountered in treatment of drinking waters are numerous.
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