Modern UV-C science knowledge

Division of ultraviolet wavebands
The International Commission on Illumination (CIE) has given a clear band definition for ultraviolet radiation. Electromagnetic radiation from 100nm to 400nm is called ultraviolet radiation.
It is specifically divided into three wavebands, namely UVA, UVB, and UVC.
Among them, the UVC waveband range is 100nm to 280nm. Since 100nm to 200nm belongs to vacuum ultraviolet and is quickly absorbed by oxygen in the air (forming ozone), therefore, the UVC waveband is often understood as the wavelength range of 200nm to 280nm. Moreover, UVC is the most effective waveband for sterilization, so the ultraviolet sterilization waveband is often abbreviated as ultraviolet C.
The UVB waveband range is 280nm to 315nm.
The UVA waveband range is 315nm to 400nm.

Principle of modern UV-C disinfection
Modern ultraviolet C disinfection technology is based on optics, biology, chemistry, mechanics, electronics, fluid mechanics, aerodynamics, and civil engineering. It uses a specially designed high-efficiency, high-intensity, and long-life C-band ultraviolet light generating device to generate strong ultraviolet C light to irradiate water or air. When various bacteria and viruses in water or air pass through the ultraviolet C irradiation area, ultraviolet light will penetrate the cell membrane and nucleus of microorganisms and destroy the molecular bonds of nucleic acids (DNA or RNA), making them lose their replication ability or activity. Since cells cannot replicate, microorganisms will soon die, thus killing all bacteria and viruses in water or air without using any chemical drugs.
Ultraviolet C disinfection does not produce any secondary pollutants and belongs to the latest generation of disinfection technology in the world. With its advantages of high efficiency, broad spectrum, low cost, long service life, large water volume, and no pollution that other disinfection methods cannot match, it has gradually become a mainstream disinfection method in developed Western countries.

Advantages of modern ultraviolet C disinfection technology
The disinfection effect of ultraviolet C water disinfection technology on bacteria, viruses, and other pathogens has been recognized worldwide. Ultraviolet C water disinfection technology has the following obvious advantages:
High-efficiency sterilization
Ultraviolet C disinfection technology has an incomparable sterilization efficiency compared to other technologies. The sterilization efficiency can reach 99% - 99.9%. Table 1 lists the sterilization time of ultraviolet C technology for several common bacteria and viruses, which generally only takes less than one second. In contrast, traditional chemical disinfection methods such as chlorine and ozone generally require 20 minutes to one hour to achieve the sterilization effect of ultraviolet C.

Efficient sterilization with broad spectrum

Ultraviolet C technology in all the disinfection technology, the broad spectrum of sterilization is the highest. It can kill almost all bacteria and viruses efficiently. And it can effectively kill some parasites that are very harmful to humans, and chlorine gas and ozone cannot or cannot effectively kill (such as cryptosporidium, giardia, etc.). Table 1 also shows the broad spectrum of sterilization of UV-C water disinfection equipment.

No secondary pollution

Since UV-C technology can be controlled to only sterilize and do not add any chemical agents, it will not cause secondary pollution to the water body and the surrounding environment. It doesn't change anything in the water. For chlorine disinfection, the organic chlorine produced with organic matter in water has been recognized as carcinogenic to the human body, and the chlorine compounds contained in water will be counterproductive in some cases, causing toxicity to water organisms and the water environment. The ozone method has similar problems. A large number of unpleasant ozone that is not dissolved in water volatilizes into the air, which is harmful to the physical and mental health of nearby workers.

Safe and reliable operation

Traditional disinfection technology such as the use of chloride or ozone, the disinfectant itself is a highly toxic, flammable, explosive substance. The use of these substances poses a potential threat to the safety of personnel at the operation site, as well as the surrounding environment and residents, and requires special care. China's public security, fire protection and environmental protection departments have strict transportation, preservation and operation regulations for the use of these high-risk substances. All these have greatly increased the psychological burden and insecurity of the leaders, operators and surrounding residents of the grass-roots units. Modern UV-C disinfection systems do not have such safety risks, and are a much safer and more reliable disinfection technology for the surrounding environment and operators.

Low operating and maintenance costs

Usually an efficient technology is associated with high cost, high operating expenses. However, UV-C technology is an exception. Due to the improvement of the UV-C core technology in the 1990s, UV-C disinfection technology is not only the highest disinfection efficiency of all disinfection means, but also the simplest disinfection operation and maintenance, the lowest operating cost, in the thousand tons of processing capacity level can reach 4 percent per ton of water or even lower, therefore, its performance-to-price ratio is the highest in all disinfection technologies. It not only has the high efficiency that other disinfection technology cannot match, but also has the advantages of low cost and low operating cost. At the level of 1,000 tons of water treatment capacity, its cost is only 1/2 of chlorine disinfection, 2/5 of chlorine and dechlorination, and only 1/9 of the cost of ozone disinfection. Even at the 100,000 tons processing capacity level, the investment and operating costs of ultraviolet C are far lower than other disinfection technologies.

Easy to install and operate

Uv C disinfection system is modular design, easy to install, suitable for any installation site conditions, does not damage the site equipment, pipelines and building structures. The system only needs to be connected to the power supply, can run continuously 24 hours a day, 365 days a year, no downtime when cleaning the lamp, in addition to regular 1-2 hours of routine maintenance, can be used without interruption. The operation of chlorine and ozone disinfection is complex, and the quality requirements of operators are high, and any negligence may reduce the disinfection effect and even cause serious accidents.

Small footprint, no noise

The ultraviolet C disinfection equipment that treats 10,000 tons of water per day only needs 4 square meters of operation space, and the ultraviolet C disinfection system that treats 50,000 tons of sewage per day only needs 1 (10 meters ×2 meters) canal. The chemical disinfection method requires several times as much agent contact pool land. In addition, the UV-C disinfection equipment relies on self-flow water supply (no pump required) and does not produce any noise.

Continuous mass disinfection

At present, ultraviolet disinfection technology has reached 1.5 million tons of water per day in practical application, and can be larger if actual needs, which is difficult to do with chlorine and dechlorination and ozone disinfection methods.

Wide application field

Of all the current disinfection technologies, none has such a wide range of applications as the UV-C technology. It can be widely used in a variety of water bodies (clean water, sewage, seawater, etc.) and air disinfection field, suitable for all walks of life disinfection requirements. Its main application areas are:

Water disinfection: tap water, secondary water supply, direct drinking water, pure water, aquaculture, food and aquatic product processing water, beverage water, medical water, electronic high purity water, etc.

Sewage disinfection: municipal sewage, reclaimed water, hospital water, oil field reinjection;

Circulating water disinfection: swimming pool water, landscape water, industrial circulating cooling water;

Shellfish purification, agricultural irrigation water disinfection, algae removal in large water bodies;

Disinfection of military bases, field operations, aircraft, ships and submarines with water;

Central air conditioning system air disinfection.