The wavelength of ultraviolet light ranges from 40 nm to 400 nm. Because the wavelength is too short, it is difficult for human eyes to see. According to the wavelength, it is divided into A-band, B-band, C-band and vacuum ultraviolet. The wavelength of C-band is 200 nm -275 nm.
C-band ultraviolet rays are used for water disinfection. Ultraviolet rays have the best bactericidal effect in the wavelength range of 240 nm-280 nm, especially in the wavelength range of 253.7nm. A section of C-BAQND in ultraviolet rays is very useful in killing bacteria or viruses harmful to human body. Its sterilization principle is to destroy the DNA (deoxyribonucleic acid) structure of the life center of single-celled microorganisms such as cells and viruses by ultraviolet irradiation, so that protein, which constitutes microorganisms, cannot form, and immediately dies or loses its reproductive ability. Generally, ultraviolet rays can achieve sterilization effect within 1-2 seconds.
At present, it has been proved that ultraviolet rays can kill bacteria, molds, viruses and unicellular algae. In fact, all microorganisms are sensitive to ultraviolet rays, so ultraviolet rays are superior in water treatment.