Saturday, December 6, 2014

Guide To Portable Water Purifiers For Survival

By Claudine Hodges


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).

After undergoing coagulation treatment, the waters will be transferred to another basin where will actually start accretion. Indeed, nothing prevents the gathering of more then neutralized colloids. We must therefore maintain a slow stirring to encourage accretions. It is accelerated by the addition of polymer, that is to say a large molecule formed by the repetition of basic pattern that traps colloidal materials and agglomerated forming large flakes which settle by gravity. This is the "flock".

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:

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 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.

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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