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A filtered process

In last fortnight’s column we examined the problems associated with four major types of water purification systems that account for nearly 100 per cent of market share; Silver nano, UV and Chlorine treatment had one important health concern and the other system, RO was found wanting due to the high percentage of water wastage.

Modern Indian Science

Scientists at the BARC have developed a unique water purifier technology that addresses all the concerns mentioned earlier. The core filtration process uses a mechanical polysulfone membrane in a cylindrical shape with a porosity of 0.01 micron which delivers 99.99 per cent pure water. The sizes of the smallest known microbes are in the range of 0.02 micron which makes the filter highly effective. This is an improvement over UV systems which only deactivate the microbes and do not filter them out which means that its users drink inert or dead bacteria. The polysulfone material is very robust and has a useful life of 3-5 years. This BARC system has zero maintenance cost since it does not use electricity nor does it have any recurring parts that need to be changed regularly. It also removes turbidity and delivers crystal clear water. This makes it an ideal filter even for low income groups and BARC estimates that the production cost of this system to be just Rs.550/- per unit.

BARC is willing to license this technology to any interested manufacturer in India and a few companies today use this as the basis for commercial water purification products. However all these licensees add other filtration steps like an activated carbon filter to the core polysulfone membrane filter to improve the quality of the water. It depends on us to choose a product that meets our needs. Ironically some of these manufacturers use the BARC technology as an input to RO water systems, defeating the purpose. The BARC website provides a list of manufacturers who have licensed their water filtration technology. Readers can check this information if they wish to buy these products.

Ancient Indian Science

In Ayurveda, copper has been identified as a metal that kills pathogens to provide safe drinking water. Storing water overnight in a copper pot kills several pathogens that cause serious diseases like cholera and typhoid. These diseases claim 2.2 million lives annually worldwide, especially affecting children under five years. This Ayurvedic concept has been reinstated in several studies including those by the National Institute of Cholera & Enteric diseases at Kolkata.

It must be noted here that hot water should not be poured directly into the copper pot. If the water has been boiled, then cool it to room temperature before storing it in the copper pot. Every few days the copper vessel should be cleaned like any other utensil. The copper pot literally lasts a lifetime and of course does not have any recurring maintenance cost.

In my home we use a mechanical filter based on the BARC technology to provide the first level of purification. The water from this filter is directed to a copper pot which stores the water and delivers an added level of purification and of course peace of mind from water borne diseases.

The author is an environmentalist and CEO of Krya, a company that deals in products for sustainable urban living. Mail her at

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Printable version | Jan 22, 2021 8:52:01 AM |

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