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Overview Of Portable Water Purifiers For Survival

By Claudine Hodges


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;

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).

In rotation, a portion of drum emerges allowing to free the network from the materials retained by the waters spray. The washing waters is collected in a gutter and sent to sludge line. Sieves and microstacci are constructively similar, differing only in size of holes of filter screens. The passage openings can even a few millimeters so the treatment is more efficient for the fine screening.

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.

The primary sedimentation uses the force of gravity for removing the solid sediments predominantly inorganic (sand, loam, silt, etc.). It is adopted as pretreatment physical limited to waters with high turbidity (1,000 mg / l) and / or with silica in suspension. In these cases, is inserted upstream of flocculation in order to lighten the load coming.

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.

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.




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