Industry Applications
The advantages of using UV light to kill waterborne infectious bacteria have been widely recognized. In fact, industry was one of the early adopters of this technology. Today, almost all industries use UV technology in water treatment systems, including food and beverage, pharmaceutical, cosmetic, health care, manufacturing, high-tech industries, etc. Sterilization is the main application of UV technology in the field of water and wastewater. At the same time, industry also uses this technology in many other aspects, including ozone removal, total organic carbon (TOC) reduction, liquid sugar disinfection, degradation of LV gas, surface and air, and cooling tower disinfection. This article will briefly summarize some of the uses of UV in industry.
Sterilization
UV sterilization mainly uses ultraviolet light with a wavelength of 254 nanometers. This wavelength of ultraviolet light, even at a trace dose of ultraviolet radiation, can destroy the core of a cell's life - DNA, thereby preventing cell regeneration, losing the ability to regenerate and rendering bacteria harmless, thereby achieving the effect of sterilization. Like all other UV application technologies, the scale of this system depends on the intensity of the UV light (the intensity and power of the irradiator) and the contact time (the length of time the water, liquid, or air is exposed to the UV light).
Ozone Removal
In industrial production, ozone is often used to disinfect and purify water. However, due to its strong oxidizing power, residual ozone in the water may affect the downstream process if it is not removed. Therefore, the residual ozone in the water must be removed before the ozone-treated water enters the main process. 254-nanometer ultraviolet light is very effective in destroying residual ozone, which can decompose ozone into oxygen. Although the scale required for different systems varies, in general, a typical ozone removal system requires about three times the amount of ultraviolet radiation as a traditional sterilization system.
Reduce Total Organic Carbon
In many high-tech and laboratory settings, organic matter can hinder the production of high-purity water. There are many ways to remove organic matter from water, and the more common methods include the use of activated carbon and reverse osmosis. Shorter wavelength ultraviolet light (185 nanometers) can also effectively reduce total organic carbon (it is worth mentioning that these emitters also produce 254-nanometer ultraviolet light, so disinfection can be performed at the same time). Shorter wavelength ultraviolet light has more energy and can therefore break down organic matter. Although the reaction process of UV oxidation of organic matter is very complex, its main principle is to oxidize organic matter into water and carbon dioxide by producing free hydrogen and oxygen with strong oxidizing ability. Like ozone removal systems, the UV radiation of this UV system for degrading organic carbon is three to four times that of traditional disinfection systems.
Liquid sugar disinfection
Most food and beverage manufacturers use a large amount of liquid sugar. Since sugar is easily used by bacteria, it is easy to promote bacterial growth. In addition, liquid sugar is opaque, so it is difficult to disinfect thoroughly. Ultraviolet light with a wavelength of 254 nanometers can be used to disinfect liquid sugar products. In order to compensate for the energy loss caused by the viscosity and color of the liquid, many UV emitters need to be closely arranged to form a so-called "thin film" reactor. This close combination of emitters can provide the required very high UV radiation, so that liquid sugar can be effectively disinfected. Its UV energy output is about 7 to 10 times that of traditional disinfection systems.
Degradation of residual LV
In municipal water treatment and water supply systems, LV disinfection is very necessary. However, in industrial production processes, in order to avoid adverse effects on products, it is often necessary to remove residual LV from water as a pretreatment. The basic methods for eliminating residual LV are activated carbon beds and chemical treatment. The disadvantage of activated carbon treatment is that it requires constant regeneration and often encounters problems with bacterial growth. Ultraviolet rays with wavelengths of 185 nanometers and 254 nanometers have both been proven to effectively break the chemical bonds between residual LV and LV ammonia. Although it requires huge UV energy to work, its advantages are that this method does not require any drugs to be added to the water, does not require the storage of chemicals, is easy to maintain, and has the function of sterilizing and removing organic matter at the same time.
Surface and air disinfection
The use of ultraviolet rays for air disinfection has a long history, just like ultraviolet rays for water disinfection. Air disinfection equipment has been used in hospitals, clinics and clean rooms for many years. Now, factories, offices and homes have begun to use air disinfection equipment.
The principle of air disinfection is the same as that of water disinfection. Usually, the ultraviolet lamp can be installed in the air duct, at the front end of the coil, or mounted on a rack fixed to the wall. When the air passes through, the microorganisms in the air are killed and rendered harmless. The principle of surface disinfection is the same. In the food and beverage industry, products on conveyor belts are disinfected by surface disinfection equipment.
Cooling tower disinfection
In order to reduce the cost of biocides (purchase, storage, insurance) and the health hazards of chemical treatments, UV systems can be installed in the water circulation system of cooling towers to sterilize. If used in conjunction with filters, UV can effectively control the growth of microorganisms in cooling towers. Although a certain concentration of biocide still needs to be maintained in the cooling tower, the use of UV can greatly reduce its use.
The above is a brief basic overview of the development and application of UV technology in the industrial world.
