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A water purifier that requires no electricity, can be set up in 10 minutes in the remotest areas, and that filters out even viruses, has been developed by the polymer division of the National Chemical Laboratory. The filter has immense potential in rural and disaster-prone areas
The polymer division of Pune's National Chemical Laboratory (NCL) has come up with a new membrane filter that ensures the quality of your drinking water. A unique aspect of the ultra filtration (UF) membrane is that not only does it clean the water of all suspended particulate matter and bacteria, it also gets rid of harmful viruses. The membrane technology, which was granted a US patent earlier this year, does not depend on electricity, unlike other water filters. It can be used in remote rural areas as well as disaster zones where safe drinking water is not easily accessible. High water permeability, low fouling and the ability to reject undesirable species in the water (worms, spores, bacteria, viruses, etc) are some of this filter's noteworthy characteristics. While other water purifiers in the market are based on various principles of water purification like distillation, ion exchange, reverse osmosis, ultraviolet filtration, activated carbon absorption, etc, membrane-based separation is more effective as it works on the principle of physical exclusion of pathogenic species like viruses and bacteria. According to scientists, the membrane is so fine that only the tiniest of molecules (water and salt) pass through it. Larger molecules, viruses and bacteria remain on the surface of the membrane. "There is no chemical process involved in the filtration using this particular membrane. The membrane works on pressure as the driving force. The minimal pressure requirement is 0.5 bar, which can be generated by a mechanically operated pump or can be obtained through an overhead tank placed at an appropriate height," says the NCL's Dr P K Ingle. All membranes and modules developed at the NCL have been tested and validated by leading research institutes such as the Agharkar Research Institute and National Institute of Virology (NIV) in Pune and the National Environmental Engineering Research Institute (NEERI) in Nagpur. In order to study the quality of water purified using the ultra filtration membrane, field trials were conducted as long ago as November 1999. Fifteen hand-operated water purification units based on this technology were airlifted to cyclone-affected areas near Paradip in Orissa on November 13, 1999. A quality check, carried out by NEERI, revealed that the purified water had no bacterial count. The technology has thus proven highly appropriate for extreme circumstances, in regions where the quality of potable water is poor and electricity simply not available. The filtration units are portable and can easily be carried to remote areas. Once the NCL was satisfied with the standard of water purification, the technology was transferred on a royalty basis to Pune-based entrepreneur Subhash Devi. The filter is currently being manufactured at a factory in Shivapur, which is capable of producing 2,000 units a month. The ultra filtration membrane is being marketed under the brand name 'Purioin'. One version of the membrane, Purioin XL, that costs Rs 18,000, has been designed specifically for rural application. The membrane is fitted with a hand pump and can purify 150 -200 litres of water in an hour, without using electricity. This easy-to-deploy rural version of the filter weighs just 18 kg and can be fitted in 10 minutes using any available water source. The principle of the village level filtration unit is fairly simple. A mechanically-operated pump circulates water from a ground-level tank to the membrane module, at a given pressure, in a tangential direction so that any large molecules or particles are pushed ahead and do not block the pores of the membrane. Pure water subsequently flows out. Purioin is available in two other versions -- Purioin Plus, that costs Rs 7,500 and filters one litre of water per minute, and Purioin Elite that can filter two litres of water per minute and costs Rs 10,500. The ultra filtration membrane does not need to be replaced for at least three years. According to Devi, water filtered through the NCL device costs around 5 paise a litre. That's much less than the mineral water bottles available today. "The filter can be used in schools, at bus and railways stations, hospitals and in disaster areas." But funds are the biggest worry. "The government must provide the initial boost, as this filter system provides the solution to India's drinking water problems," says Devi. While the department of science and technology has ordered 150 units to test in different parts of the country, Devi is disappointed with the response of local governments, which have not taken a serious note of the product. In order to create awareness and popularise the product, the department of science and technology is also providing units to civil society organisations working in the area of public health. The National Dairy Development Corporation too has asked for 100 units to purify water used to clean its milk storage tanks at collection centres near Gandhinagar. Polymer scientist R A Mashelkar, director general of the Council of Scientific and Industrial Research and the head of the team that developed the membrane filter describes this development as making high technology work for the poorest of the poor in India. Contact: Subhash Devi
Membrane Filters (India) Pvt. Ltd
A-3, Saket, 45/1, Next to Patwardhan Baug,
Karve Nagar, Pune - 411 052
Tel: 020- 56241874 / 09822099528
Email:
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- Durga Chandran InfoChange News & Features, August 2005
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