Overview Of Survival Water Purification Systems

By Stacey Burt


Filtration is the removal of contaminants from 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) (survival water purification systems).

Quick filters are identical to those lenses; only varies the thickness of material forming the filter bed and the mattress filtering, in order to make faster the speed of filtration, equal to 5-10 m / hour. In this case the filtration is mechanical. For quick filters as a rule are used leach monolayer (single media) consisting of quartz sand (50-80 cm thick) supported by a mattress filter, or a drainage layer, consisting of coarser material (such as gravel) the thickness.

Filtration is a treatment used to remove suspended solids from the waters not sediment. Treatment consists in passing the raw waters through a filter medium (bed / filter layer or filter cloth). In case of filter layer, the filter material can be made from quartz sand, anthracite or activated charcoal. During filtration the filtered solids gradually begin to clog the filtering layer resulting in an increase of load losses, which is increased to overcome the supply pressure. Exceeded the maximum value of said pressure must be made to interruption of flow and to cleaning of filter medium.

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 entered into a tank head from which it originated the system of waters supply - drinking. The waters containing different types of organic substances and inorganic, hereinafter classified, that must be removed during the purifying treatment. Physical treatments simple: they are articulated in a single step, eliminating the suspended solids and sediments those not coarse sediments (screening and sedimentation) and non-settleable (sieving and filtration).

Forms special surface filtration membrane processes are divided according to size of pores in: microfiltration, ultrafiltration, nanofiltration and hyperfiltration or reverse osmosis. Filtration membranes can be used for example as an alternative to or flocculation processes adsorption.

The flocculation basins have a rectangular shape and can be: Staged: where to achieve greater efficiency, the tank is divided into several zones in series in which the agitation is gradually decreasing. Channels: are horizontal flow, where the pool is subdivided by transverse partitions to form a channel whose width is gradually increased so as to obtain a flow velocity gradually decreasing.

The filters are formed from cylindrical vessels made of reinforced concrete on the bottom of which special shelves, provided with an adequate number of holes, support the filtering mass. The filter bed consists of fine sand / fine or other material minute. The filter bed is supported by an underlying layer of material, also the filter, formed by a layer of coarse gravel and the overlying layers of gravel gradually finer (mattress draining).

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. Decanters flow or vertical upward flow are generally circular section. Inse tanks the entrance of waters can be centrally from above; in this case waters, to be able to escape from the tank itself is forced along a tortuous path; in fact must first move vertically downwards in order to pass beneath a baffle concentric, said fireplace, subsequently, passed over the obstacle fireplace, must rise and exceed a weir located along the perimeter of tub.




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