The application of ultraviolet rays in water treatment has a history of several decades. However, due to its complicated technology and high cost, its application is restricted. But now foreign ultraviolet technology has been widely used, banned traditional chlorination disinfection, and the price is lower than traditional chlorination disinfection. In the 1970s, due to increased water pollution and increased public health awareness, people were forced to adopt new methods based on traditional water treatment processes to ensure that the quality of the water supply meets safer drinking water standards. After nearly two decades of research and practice, the composite application technology composed mainly of ultraviolet rays has become the first choice for deep purification of water supply due to its good treatment effect.

(1) Ultraviolet light is used for disinfection of effluent from secondary treatment of urban sewage to meet domestic landscape and greening water requirements.

(2) The technology has the characteristics of no secondary pollution and broad application prospects.

(3) Low energy consumption, low operating costs; high degree of automation; easy maintenance.

In addition, the ultraviolet sterilized sewage can be reused in many fields to realize the recycling of sewage. It can be used to irrigate farmland, woodland and lawn, etc. to avoid the damage of plants by chemical disinfectants; it can be used to recharge groundwater to prevent microbial adaptation to chemical disinfectants and the blockage of the ground caused by reproduction again. With the in-depth study of the mechanism of ultraviolet disinfection, the continuous development of ultraviolet technology and the continuous improvement of the design of disinfection devices, ultraviolet disinfection is expected to become one of the main methods to replace traditional chlorination disinfection.