Water Purification Methods Used in Household Water Purifiers

Water purifiers are functional household items that have been playing an important role in providing healthy lives to the individuals. With health conscious among the individuals increasing like never before, many companies have come up with affordable yet serviceable technologies of water purifiers.

Since water purifiers are very helpful in these days where pollution is at its peak, it is better to know the technologies behind the water purifiers so as to make an informed purchase.

1. Activated carbon filtration: Activated carbon filtration, also called as carbon adsorption technique is one of the popular techniques used for home water purification. In this method, activated carbon is used to filter the water. Activated carbon, a highly absorbent material effectively attracts and traps many of the impurities in water. Many toxic organic compounds like pesticides, chlorinated solvents, etc., and microorganisms can be adsorbed by these filters.


  • Activated carbon filters remove unpleasant tastes and odors of water, including chlorine.
  • More activated carbon in the filter improves the quality of water and the lifetime of the cartridge.
  • Works without electricity


  • Water at higher temperatures affects the performance of the carbon filters. So, lower temperature waters are often recommended to use in these filters.
  • Limited lifetime – once the surface of the cartridge becomes saturated with adsorbed chemicals, it cannot adsorb anymore and hence needs to be replaced.
  • Carbon adsorption will not affect the heavy metals and dissolved solids in the water.
  • Can generate carbon fines into the water.
  • Effective when combined with other purification methods.

2. Ultra-Filtration (UF) method: Ultra-Filtration is a type of membrane filtration, in which the water is forced against the membrane containing several tiny pores. The pore size of ultra-filtration membranes range from 0.01-0.1 micrometers (1 micrometer is one millionth of a meter). This method of filtration removes dirt, suspended solids, bacteria, viruses, germs and their eggs, endotoxins, other pathogens and produces very pure water with low slit density.


  • The size of the smallest virus and germ is more than 0.02 micron and hence UF method is effective in eliminating most particles, pathogens, microorganisms, and colloids above their rated size.
  • Produces high quality of water with less usage of energy.


  • Ultra filtration cannot remove any dissolved inorganic substances from water.
  • To maintain a high pressure water flow, regular cleaning is required.
  • Effective when preceded by carbon adsorption or when combined with other purification methods.

3. Reverse osmosis (RO) method: Reverse osmosis is also a type of membrane filtration but the pore structure of RO membrane is much smaller (0.0001microns) and tighter than UF membranes. This helps them to reject 90-99% of the contaminants from water, making it one of the effective and economic options of water purifying. One more unique characteristic of a RO purifier is that it removes all the dissolved salts, metals and chemicals from the water.


  • RO process removes several impurities from water like total dissolved solids (TDS), turbidity, asbestos, lead and other toxic heavy metals, radium, and many dissolved organics.
  • Converts hard water to soft water.
  • A combination of RO and carbon adsorption is the most effective treatment.
  • Less maintenance required.


  • Reverse osmosis removes healthy minerals like calcium and magnesium from the water.
  • Because of small pore size, flow rate of water is slow and hence storage tanks are required.
  • Chlorine may pass through the membrane and can also damage it and hence a combination of RO and Carbon adsorption becomes most effective treatment.
  • Expensive when compared to other water purifying methods.
  • Professional maintenance required.

4. Ultraviolet (UV) filtration method: The unique quality of ultra violet rays to kill harmful bacteria and microorganisms is used in this filtration method. This method of filtration is mostly used for disinfecting the water. UV rays penetrate into the cells of bacteria and viruses and destroy their ability to reproduce. Without reproduction, the organisms cannot multiply and eventually die.


  • An effective UV purifier kills 99.99% of harmful microbes.
  • This method will not release any chemicals compounds into the water.


  • Decreases the resistivity of water.
  • Will not remove any dissolved salts, particles, or ions from water.
  • Uses electricity.
  • Professional maintenance required.

All these technologies when used in combination of two or more technologies will yield better results than using individually.

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