Indian scientists develop Mercury-free Lamp for Water Purifiers

The use of ultraviolet lamps in water purifiers is common but the presence of mercury in these lamps could be potentially hazardous. Now a group of Indian scientists have developed a mercury-free ultraviolet lamp that can be used in water purifiers.

Scientists have engineered an optimised dielectric discharge based mercury-free Vacuum UV/UV light source for water sterilisation. The lamp can produce desired level of wavelengths for deactivation of bacteria within 10 seconds without the use of mercury.

The lamp has been developed by scientists from two CSIR labs – Central Electronics Engineering Research Institute (CEERI), Pilani, National Environmental Engineering Research Institute (NEERI), Nagpur- working along with Birla Institute of Scientific Research (BISR), Jaipur.

Naturally available water may contain pathogenic organisms and toxic compounds. UV radiation is preferable for water purification over chemical treatment.

UV radiation is widely used for water sterilisation as it does not create any byproduct during treatment and does not alter the taste of water. It also does not eliminate minerals. But it has several disadvantages which include start-up time, filament failure, sleeve breakage, dimensional restrictions and non-reparability.

Mercury containing UV-lamps generate a considerable amount of toxic mercury waste at the end of their life as a typical UV lamp contains 20 to200 mg of mercury.

The unique structural design of the lamp enables it to produce desired UV wavelengths. The lamp has been tested for five types of bacteria – E. coli, Shigella boydii, Vibrio, coliforms and fecal coliform. Within ten seconds, all bacteria got deactivated.

“The lamp been tested further for water with turbidity level and its on-time efficiency has been found to be 200% as compared to standard equivalent mercury based UV-lamp”, said Dr Ram Prakash from CEERI. The research team included Dr Ram Prakash, Afaque M Hossain, Dr UN Pal, Dr N Kumar, Dr K Khairnar, and Dr M Krishna Mohan.



Sourced from ISW