water impurities are of many types : like bacteria, viruses (living organisms), solid visible impurities (gross particles), metallic salts, and odour.
prior to we discuss types of purifiers all of you must know that all purifiers use a filter membrane and a chamber of activated silver impregnated carbon chamber for removal of gross impurities and odour and colour impurities.
this is the basic first step in purification without which its not possible to go further by any means.
there are three types of purifiers :
ultra violet purifiers:
these work on principle of destroying living organisms by way of ultra violet radiation. these will render living organisms incapable of reproduction and virulence but will not kill them (this is very important).
these are suitable only for soft water supply from a clean source.
reverse Osmosis purifiers:
these work on principle of change according differential concentration of salts across a fine membrane. this works almost similarly as the human kidney retaining all that is necessary and discarding unnecessary.
these will actively remove the salts which may be harmfull to the body. will also remove all the living organisms.
these are suited for situations where you get hard water with suspended ppm more that 250-300 which may cause digestive problems, urinary problems, kidney stones and many other ailments according to the impurities present.
cons of RO systems:
high cost of installation
very high cost of maintainance
lot of water wastage.
third one is ultra filtration method:
these machines work on principle of very fine membrane which is so fine that it also removes all the things including living organisms larger than size of 0.001 micron.
these machine will work without any electricity unlike other types and its absolutely safe. and almost nil maintainance.
my personal opinion:
UV purifiers are unnecessary evil.
RO systems are good where the water quality is hard and taste is very bad.
UF systems are really good and usefull. but they can be used where the water supply is soft (river water, municipal supply).
i myself personally using the Ultra filtration type at my home.
there are a lot of companies making RO machines in INDIA but the basic fact is that not a single of them is manufacturing the membrane responsible for that.
the membrane is made by Permionics India Limited only its the OEM supplier of all RO system manufacturers.
the ultra filteration concept is being marketed in india by permionics india only at present.
ps edit : @darky : thats too much for him
