Principle of UV sterilization

All known forms of life on Earth rely on DNA and RNA as the basis for reproduction and survival. Both DNA and RNA are composed of four chemical units
A-Adenine adenine
T-Thymine thymine
C-Cytosine, Cytosine
G-Guanine Urapurine (the basic component of nucleic acid)
During cell proliferation, long strands in DNA are opened, and each long A unit searches for T units to join together. Each long strand can replicate the same chain as the newly separated one, restoring the original intact DNA before division and becoming the basis for new cells. Ultraviolet radiation with wavelengths between 240-270nm can break the ability of DNA to produce proteins and replicate. After the DNA and RNA of bacteria and viruses are damaged, their ability to produce proteins and reproduce has been lost. Due to the short lifespan of bacteria and viruses, those that cannot reproduce will quickly die.

The advantages of ultraviolet disinfection technology
The disinfection effect of UV-C disinfection technology on bacteria, viruses, and other pathogens has been recognized worldwide. The UV-C-disinfection technology has the following obvious advantages.
1. UV C-disinfection technology has unparalleled sterilization efficiency compared to other technologies
Table 1 lists the bactericidal efficiency of UV-C technology against several common bacteria and viruses. As shown in Table 1, the bactericidal effect of ultraviolet radiation on bacteria and viruses is generally within one second. For traditional UV, chlorine, and ozone methods, achieving the effect of UV generally takes 20 minutes to an hour.
Table 1 Sterilization efficiency of UV C-water disinfection equipment against common bacteria and viruses (UV radiation intensity: 30000 μ W/cm2)

2. Efficient sterilization with broad-spectrum properties
UV technology has a high broad-spectrum bactericidal effect among all current disinfection techniques. It can efficiently kill almost all bacteria and viruses. And it can effectively kill some parasites that are extremely harmful to humans and cannot be effectively killed by chlorine gas or ozone, such as cryptosporidium, giardia, etc. Table 1 also shows the broad-spectrum bactericidal effect of ultraviolet water disinfection equipment.
3. No secondary pollution
Due to the fact that ultraviolet technology can be controlled solely for sterilization without adding any chemical agents, it will not cause secondary pollution to water bodies and surrounding environments. Do not change any components in the water. For chlorine disinfection, the organic chlorine produced by it and organic matter in water has been recognized to have carcinogenic effects on the human body, and the chloride compounds contained in water can have a counterproductive effect in certain situations, causing toxicity to aquatic organisms and the water environment. The ozone method also has similar issues. A large amount of unpleasant ozone that has not dissolved into water evaporates into the air, which is harmful to the physical and mental health of nearby workers.
4. Safe and reliable operation
Traditional disinfection techniques such as using chlorides or ozone, whose disinfectants themselves are highly toxic, flammable, and explosive substances. The use of these substances poses a potential threat to the safety of on-site personnel, the surrounding environment, and residents, and requires special caution. The public security, fire protection, and environmental protection departments in our country have strict regulations on the transportation, storage, and operation of these high-risk substances. These have greatly increased the psychological burden and insecurity of leaders, operators, and surrounding residents in grassroots units. The modern UV-C disinfection system does not have such safety hazards and is a much safer and more reliable disinfection technology for the surrounding environment and operators.

5. Simple operation and maintenance, low cost
A highly efficient technology is usually associated with high costs and operating expenses. However, ultraviolet technology is an exception. Due to the improvement of UV core technology in the 1990s, UV-C disinfection technology not only has higher disinfection efficiency among all disinfection methods, but also has simple operation and maintenance, low operating costs, and can reach 4 cents per ton of water or even lower at a processing capacity of one thousand tons. Therefore, its performance price ratio is higher among all disinfection technologies. It has the advantages of high efficiency that other disinfection technologies cannot match, as well as low cost and operating expenses. At the level of a thousand tons of water treatment capacity, its cost is only half of chlorine disinfection, 2/5 of chlorine plus dechlorination disinfection, and only 1/9 of ozone disinfection cost. Even at a processing capacity of 100000 tons, the investment and operating costs of ultraviolet disinfection equipment are far lower than other disinfection technologies.

6. Small footprint and no noise
Our company produces UV C-disinfection equipment. For the NLC-2000 equipment that processes 80 tons of water per hour, it occupies only 1.7 meters by 0.8 meters, is 1.5 meters high, and weighs 220 pounds. If sufficient space is reserved, the system requires a total of 4 square meters of operational space. If the amount of water processed decreases, the equipment's footprint will correspondingly decrease. In addition, if the UV disinfection equipment relies on a self flowing water supply (waterless pump), it will not produce any noise.
7. Continuous high water disinfection
Another characteristic of UV-C disinfection technology in the late 1990s was continuous operation 24 hours a day, 365 days a year. The ideal operating condition for it is 24-hour continuous operation, except for regular maintenance within one or two hours. Large volume disinfection is another major feature of modern ultraviolet technology. In addition to disinfecting small amounts of water (tens of liters per hour), it can also disinfect large amounts of water. At present, the ideal state of ultraviolet technology in practical applications has reached 60000 tons per hour. If needed, it can be even larger.
8. Wide range of applications
Among all the current disinfection technologies, there is no one with such a wide range of applications as ultraviolet technology. It can not only disinfect fresh water, but also disinfect seawater; Not only can it disinfect drinking water, but it can also disinfect wastewater. It can be widely used in various fields that require water disinfection. For example, disinfection of aquaculture seawater, purification of shellfish, agricultural processing water, purified drinking water, ultra pure water for electronics, medicine, biotechnology, various beverages, beer, and food processing, disinfection after sewage treatment, tap water disinfection, water for swimming pools, urban fountain decoration, cooling water for central air conditioning and power plants, and water for military bases, ships, submarines, etc.
The comparison between modern UV disinfection technology and traditional disinfection technology is shown in Table 2. It overcomes the shortcomings of existing traditional disinfection techniques. During the disinfection process, no chemicals are added, and no harmful substances are produced or left in the water. It operates safely and reliably, with simple installation and maintenance, especially low investment and operation maintenance costs, and excellent disinfection effect. Many European countries, as well as Canada and the United States in North America, have revised their environmental legislation in the 1990s, recommending the use of UV-C disinfection technology for disinfection of wastewater treatment and drinking water.

Table 2 Comparison between UV-C disinfection technology and several traditional disinfection technologies

Comparison diagram of water bacteria cultivation