The three most used materials are: sand, used in filtration, is a natural material, silica, from rivers, natural deposits, dunes or obtained from marine pebbles. Its actual density is from about 2.5 to 2.7. Sharp sand is obtained by a career flint grinding or sea pebbles, followed by washing, drying and sieving. It presents angular grains, favor the retention of particles during the filtration (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.
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:
Stokes' law is valid for spherical particles whose size does not exceed 0.1 mm. As a first approximation, it is applied to any sedimentary particles of small size (sand, silt, clay). One of simplest techniques for settling is static settling for example with a vertical clarifier. Power is supplied from the bottom, the particles sediment and may be recovered at the bottom of cone, while the treated waters is discharged from the top by overflow. The sedimentation rate is unfortunately generally low.
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 screening aims to retain coarse solids non settleable (branches, leaves, rags, plastic, etc.) And solid coarse sediment (gravel, etc.). Among these materials Coarse including the possible fauna of waters body (fish). The grilling is adopted in all the patterns of surface waters treatment, and in this case is placed upstream of other treatments.
For waters of Category A1, may be the only physical treatment in addition to disinfection. The grid consists of series of metal bars placed at a distance such as to create obstacles to coarse bodies carried by the current. The grid is installed internally to channel coming to system, inclined with a slope generally equal to 1: 3.
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.
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:
Stokes' law is valid for spherical particles whose size does not exceed 0.1 mm. As a first approximation, it is applied to any sedimentary particles of small size (sand, silt, clay). One of simplest techniques for settling is static settling for example with a vertical clarifier. Power is supplied from the bottom, the particles sediment and may be recovered at the bottom of cone, while the treated waters is discharged from the top by overflow. The sedimentation rate is unfortunately generally low.
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 screening aims to retain coarse solids non settleable (branches, leaves, rags, plastic, etc.) And solid coarse sediment (gravel, etc.). Among these materials Coarse including the possible fauna of waters body (fish). The grilling is adopted in all the patterns of surface waters treatment, and in this case is placed upstream of other treatments.
For waters of Category A1, may be the only physical treatment in addition to disinfection. The grid consists of series of metal bars placed at a distance such as to create obstacles to coarse bodies carried by the current. The grid is installed internally to channel coming to system, inclined with a slope generally equal to 1: 3.
About the Author:
You can visit www.powerofthree.biz for more helpful information about Guide To Portable Water Purifiers For Survival.
