Approximately 71 percent of Earth’s surface is covered with water, but only 2.5 percent of it is fresh or drinking water. Out of this 2.5%, just 1 percent is accessible to us as the remaining is trapped in snowfields and glaciers. Now the irony is the 1%accessible fresh water is also contaminated by various pollutants either natural or made-made. Having access to clean and pure drinking water is the primary requirement of every human being.
With the pollutants getting more complex in nature, the water filtration technologies have also evolved. Long back, cloth sieving was considered enough, but today we need more advanced technologies to filter water and make it safe for consumption.
The various water purification technologies available today are as under:
- Ultra Violet Purifiers: These purifiers use ultraviolet rays to kill the microorganisms present in water. Various microorganisms such as E coli, Coliform Bacteria, Salmonella, Cryptosporidium and Giardia etc.,present in water cause a number of diseases. This includes gastro problems, dysentery, typhoid, cholera etc. The UV rays penetrate through the cells of these microbes and render them ineffective by destroying their reproduction cycle. The water that you get becomes safe for human consumption.
- Reverse Osmosis: In this successful water filtration technology, the water flows from a region of higher solute concentration through a semi-permeable membrane towards that of lower solute concentration. When the water molecules pass through this membrane with pressure, the impurities get stuck behind in the membrane.
- RO + UV: The latest is the RO + UV water purifier, which makes use of both ultraviolet and reverse osmosis technologies. In this, the UV rays help in killing the bacteria and the RO filters help in removing the dissolved salts from water, thereby making water suitable for consumption. Though these purifiers are slightly expensive, they provide complete peace of mind and are required in most of the urban spaces where the water quality has depleted too much.
- Gravity Purifiers: Gravity-based water purifiers use UF or activated carbon instead of electricity to purify municipal corporate and tap water. UF uses a cluster of hollow membrane fibres, which trap the impurities when water passes through it. On the other hand, activated carbon made of small sized carbon granules absorbs the impurities present in water. This kind of purification eradicates hazardous microorganisms like cysts and bacteria besides other impurities such as sand, chlorine, and dust. Gravity purifiers make water healthy and safe for consumption as they don’t use chemicals like iodine, bromine or chlorine for water purification.
Other than these technologies, efforts are on to find ways, which can not only remove macro, micro- and nano-pollutants, but also treat saline water and make it fit for consumption. The efforts are working and if they can be made economically viable then we would be able to use around 70% of earth’s water that is right now non-consumable.