The process of destroying and/or alternatively inactivation of disease-causing microorganisms in water and waste water are called disinfection. Disease-causing microorganisms can be categorized mainly in four groups. These are bacteria, viruses, amebic cysts and protozoa cysts.
Disinfection methods are as follows:
- Chemical (Chlorination)
- Physically pulling (Sedimentation and Filtration)
- Photochemical (ultraviolet)
Ultraviolet disinfection inactivates microorganism without any chemical and oxidant addition to water .By using a low-pressure mercury lamp that produces short-wave UV disinfection systems, Ultraviolet disinfection disturb the structure of DNA and RNA, and neutralize bacteria, protozoa, viruses, molds, fungi, algae, and their eggs.