Frequently Asked Questions

UV disinfection uses ultraviolet light at 254 nm wavelength to penetrate the cell walls of microorganisms — bacteria, viruses, protozoa, and mould. At this wavelength, UV-C light disrupts the DNA and RNA of microorganisms, permanently preventing their reproduction. The organism cannot replicate, so it is effectively inactivated. UV disinfection does not kill microorganisms chemically — it disables them biologically. This is why UV leaves no residuals, no taste, and no byproducts in the treated water.

UV light exists on a spectrum divided into UV-A (315–400 nm), UV-B (280–315 nm), and UV-C (100–280 nm). UV-C at 254 nm is the germicidal range — this wavelength corresponds to the peak absorption of DNA and RNA in microorganisms. It is the most effective wavelength for disinfection. Natural sunlight contains UV-C, but it is absorbed by the atmosphere before reaching Earth's surface. UV disinfection systems use low-pressure or high-output UV-C mercury lamps to generate concentrated UV-C light in a controlled chamber through which water flows.

UV disinfection is completely safe for drinking water applications. UV-C light does not make water radioactive, does not add chemicals, and does not change the taste, odour, colour, or chemical composition of water in any way. It cannot be overdosed — excess UV exposure simply produces more disinfection, not a harmful product. UV is the preferred disinfection method for pharmaceutical water (WFI), food & beverage processing, and applications where chlorine taste or chemical residuals are unacceptable.

UV-C disinfection is effective against virtually all waterborne pathogens, including: bacteria (E. coli, Salmonella, Vibrio cholerae, Legionella, Staphylococcus, Pseudomonas), viruses (Adenovirus, Norovirus, Rotavirus, Hepatitis A), protozoa (Cryptosporidium parvum, Giardia lamblia — which are chlorine-resistant), and fungi and mould. The required UV dose varies by organism: Giardia requires 10 mJ/cm², most bacteria 4–10 mJ/cm², Cryptosporidium 10 mJ/cm², and Adenovirus (most resistant) up to 120 mJ/cm². Alpha UV System designs to a minimum 40 mJ/cm² for drinking water — achieving 4+ log reduction across all common pathogens.

UV is superior to chlorine for most applications in India on five criteria: (1) No disinfection byproducts — chlorine creates trihalomethanes (THMs) and haloacetic acids, which are regulated carcinogens. UV creates none. (2) No chlorine-resistant pathogens — Cryptosporidium and Giardia are resistant to chlorine but fully inactivated by UV. (3) No chemical storage or safety hazard — chlorine gas and sodium hypochlorite require hazardous storage and handling. (4) No taste or odour change in treated water. (5) Lower operating cost in most applications. Chlorine has one advantage: residual protection in distribution pipes. For point-of-use applications, UV is the better technology in almost every case.