UV water disinfection: principle of operation, installation. Drinking water - GOST valid

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Today, innovative technologies allow high-quality water purification from various contaminants on a large scale. At the same time, the population, production, technical facilities are provided with high-quality liquid. Various methods are used in the process of water treatment. They allow you to meet all the requirements of the current GOST.

One of the most successful methods today is ultraviolet disinfection of water. This approach successfully combats certain types of contaminants, allowing large-scale fluid processing. The essence and effectiveness of this method, its advantages and disadvantages will be discussed below.

General characteristics

Today, water disinfection with ultraviolet radiation is a popular technique that is used in combination with other types of treatment. The presented processing is carried out everywhere. This is the first step in water disinfection. It allows you to get rid of harmful microorganisms in the liquid.

In the process of applying this reagentless method, water is irradiated with ultraviolet light of a certain part of the spectrum. This is electromagnetic radiation, the wavelength of which can be from 250 to 270 nm. It should be noted that the ultraviolet part of the spectrum includes rays that are in the range from 10 to 400 nm. Modern installations that allow disinfecting water produce radiation with a wavelength of 260 nm. In this case, the liquid is not only purified, but also softened.

When using this approach, other techniques are used. This can be water chlorination, as well as hypochlorination. The presented processing step is mandatory, according to GOST, when cleaning the liquid.

The principle of the method is based on the ability of ultraviolet light to penetrate cell membranes, destroying their DNA and RNA. She loses the ability to divide. The presented technique allows you to completely eliminate the negative impact on the human body of microbes and bacteria that are in the water. The strength of the impact depends on the duration of exposure. There are certain standards for such disinfection.

Standards and requirements

There are certain standards and regulations that apply to water treatment and testing. They coordinate the actions of services that are engaged in the disinfection of liquids. Such regulatory documents include guidelines MU 2.1.4.719-98, approved by the Ministry of He alth of the Russian Federation, as well as the current GOST "Waterdrinking" R 56237-2014.

The submitted regulatory documents regulate the procedure for water purification using ultraviolet light.

The guidelines presented describe the characteristics of the minimum radiation dose that applies to drinking water. This figure is 16 mJ / cm². Studies conducted by scientists have shown that with such an intensity of treatment in water, the number of pathogenic bacteria is significantly reduced. This indicator is 5 orders of magnitude. The number of viruses during this treatment is reduced by 2-3 orders of magnitude.

The current GOST "Drinking Water" regulates the interaction of all services that provide liquid processing. The standard defines the basic requirements for the production of quality measurements and cleaning. Thus, according to this document, drinking water must meet sanitary and hygienic requirements in terms of its qualities. It can be used to meet drinking and household needs. By using such a liquid, it is possible to produce products for human consumption.

Efficiency of the method

To get clean, clear water, it is not enough to use only ultraviolet radiation. There is a whole range of procedures that can demonstrate a high processing result. Only after they are held can you get drinking water.

The effectiveness of ultraviolet disinfection has a number of conditions. To obtainhigh quality of the final result, it is important to choose the right dose for liquid treatment. Its effectiveness depends on the intensity and duration of treatment. Various microorganisms are more or less resistant to such influences. For bacteria, the radiation dose may be less. Such processing has less effect on viruses. It should be noted that the most resistant microorganism to such treatment is Escherichia coli. Therefore, before processing, the presence of bacteria in the water is determined.

Also, when calculating the dose, the total number of bacteria and microbes that are in the liquid is determined.

The quality of the irradiated water is also of great importance. It may contain different amounts of impurities. Clean, clear water is better for disinfection than cloudy liquid. This is due to the degree of penetration of water deep into the layers. In order for the presented processing to be effective, the amount of impurities in the substance must be determined less than the maximum permissible value.

Standards and guidelines stipulate how much iron, large particles of pollutants, as well as the category of water color should be in the liquid. If these figures are too high, the processing will be ineffective. Behind these smallest particles, as behind a shield, some of the bacteria and viruses can hide. Therefore, they will not die during processing. Energy costs will be useless. Before disinfection, water is purified from iron impurities.

Method advantages

Knowing the principle of operation of ultraviolet disinfection of wastewater, one shouldhighlight a number of advantages of the presented method. The procedure belongs to the category of the cleanest approaches. When it is carried out, no chemicals or additional substances are added to the water. The negative impact of ultraviolet radiation on the human body can only occur with prolonged exposure. This type of disinfection does not change the chemical and physical properties of the liquid. This eliminates even indirect effects on the body.

The advantages of the method should also include its versatility. It effectively acts on almost all microorganisms. It is also a fairly economical method. It is used in most cases of disinfection. In the presence of Escherichia coli or other microorganisms resistant to ultraviolet irradiation, ozonation is used in the water. This approach is considered more expensive.

The irradiation time of the liquid does not exceed a few seconds. This provides an instant effect when conducting such an impact. In this case, there is no danger of exceeding the dose of treatment. Water can be irradiated for an arbitrarily long time. At the same time, its physical and chemical qualities will not change. Long-term treatment will be more effective.

When disinfecting water with ultraviolet radiation, it is possible to significantly reduce the amount of reagents that are used after irradiation. Also, this method does not require high energy costs, compared, for example, with ozonation. Therefore, it is used everywhere.

Flaws

Clean drinking waterobtained during the processing of the liquid by various methods. The disadvantage of ultraviolet irradiation is the inability to have a corresponding effect on all microorganisms. Some of them have high UV resistance. If such bacteria or viruses are found in large numbers in the water, it is treated differently.

Also, one of the disadvantages of the method is the need to control the level of iron. The liquid must not contain various suspended particles of pollutants. Otherwise, the processing will be inefficient. The higher the dispersed impurities of a sufficiently large size in the water, the worse the final result of processing will be.

In order for the installation that performs water disinfection with ultraviolet radiation to be able to perform the procedure with high efficiency, the technique involves pre-cleaning. This allows you to remove impurities, coarse particles of pollutants from the water. Also, after the procedure, it is necessary to carry out chlorination of water.

UV installation is a one-time operation. This does not guarantee that after disinfection, various bacteria and viruses will not appear in the water again. Due to its shortcomings, the presented technique is most often used in combination with other methods. However, in the absence of other contaminants in the water, ultraviolet can be used as an independent approach. The disadvantages of this method cannot override its advantages.

Features of disinfection devices

UV water disinfection unitdoes not have a high complexity of design. This makes the equipment easy to operate, reduces the likelihood of breakdowns. The design of the installation has the form of an elongated metal tube. Inside it is an ultraviolet lamp. Also, all models have quartz cases. Lamps are installed in them.

The construction work is simple. Water enters the unit. It runs from the inside of the quartz case. At this time, the liquid receives the necessary dose of disinfection. The quartz cover in a design protects a lamp from damage. Therefore, water washes precisely this part of the installation.

The lamp is a complex structure. In its case, the evaporation of a certain type of metal occurs. Most often, mercury is used in these devices. This metal is most often used in the process of water disinfection. The lamp must emit ultraviolet waves of a certain length. This indicator is affected by the pressure of the internal mercury vapor of the lamp bulb.

UV disinfection of water can only occur under certain conditions. High, low and medium pressure lamps are on sale. However, not all designs are used for water disinfection. For carrying out such a procedure, only those lamps in which the pressure will be low or medium are suitable. The first option is preferable. It is these lamps that are capable of emitting radiation with a wavelength of 260 nm. Such devices are noted for their high energy efficiency and long service life.

Varieties of lamps

TodayVarious systems of ultraviolet disinfection of water are on sale. Low pressure lamps are known for their highest efficiency. They have a low power rating. Their lamps are made of uviol glass. This can significantly reduce energy wastage.

Over time, each lamp gradually loses its intensity of radiation. How soon the lamp will lose its original qualities is an important argument in purchasing a particular model. At the end of its life, the lamp power may be only ¼ of the nominal initial value.

Today, both domestic and foreign products are presented on the market of ultraviolet emitters. World famous companies are UV-technik (Germany), Atlantic Ultraviolet (USA), Hanovia (Great Britain). The last of these companies is the oldest in the world in the production of such irradiators. Lamps from the Dutch company Philips are also in demand in our country.

All of the listed lamps are used in their installations by the largest manufacturers of such equipment. Domestic lamps are also in demand. For example, in our country, ultraviolet water disinfection units UDV, which are manufactured by NPO LIT, use lamps of the company's own production brand DB.

Varieties of installations

UV-disinfection of water occurs with the help of different installations. One of the popular firms is BWT. She isproduces devices for conducting water irradiation called Bewades. Such devices are characterized by a radiation dose of 40 mJ/cm². Therefore, these plants are used to treat both wastewater and drinking water. They use Philips lamps. Their operating time is 11-14 thousand hours.

There are many domestically produced units on the market for special water treatment products. They use high-quality lamps of both domestic and foreign production. So, the products of the National Water Resources company are known in our country. It launches the installation "Shine" on the market. Philips lamps are installed in these appliances.

Another well-known product in our country is the BAKT plant. It also has lamps from the Dutch Philips brand. Many designs of domestic production have a radiation intensity control system.

NPO LIT offers a wide range of installations on the domestic and foreign markets. Approximately 30 different modifications of the units are produced. You can order an individual type of design that allows you to disinfect water in the field or other varieties.

Features of water treatment

Pure drinking water can be used by humans for various purposes. To obtain such a liquid, you will need to perform certain manipulations. If the water comes from a surface source, the radiation dose should be 25 mJ/cm². In this case, the transparency coefficient of the liquid must be at least 70%.

For underground sourcesthe radiation dose should be the same as for surface sources. However, the UV transmittance must be at least 80%. Previously, such water is treated using sorption techniques before disinfection.

Liquid from any source can be purified using membrane filters. In this case, the transmittance of the rays should be 90%, and the radiation dose should be 25 mJ / cm².

Disinfection of drinking water is different from wastewater treatment. For such liquids, the radiation dose should be higher. It is 30 mJ/cm².

Recommendations for choosing an installation

UV disinfection of water will be effective with the right choice of equipment and cleaning method. Each unit offered for sale is characterized by a different performance. The action of irradiation is carried out continuously. Therefore, performance is affected by the speed at which water flows inside the unit.

It should be noted that performance could be significantly increased if there was a storage tank in the system. However, for the presented principle of disinfection, such a refinement of the design is unacceptable. The action of the rays is one-time. Therefore, if the treated liquid is mixed in a tank with dirty water, it will be re-infected.

When choosing, you need to take into account what dose the installation irradiates the water. If the water is sufficiently turbid, high power equipment will be required. Otherwise, such disinfection will be ineffective. Also on the indicator of radiation dosageaffects the number of microorganisms in the liquid. The more of them, the stronger the radiation dose should be produced by the installation.

Considering all the above parameters, you can choose the best option for equipment. Thus, the domestic manufacturer NPO LIT offers a wide range of ultraviolet irradiators. Their cost varies significantly depending on performance indicators. The price can range from 20.5 to 826 thousand rubles.

Having considered the features of ultraviolet disinfection of water, you can correctly select and use equipment for irradiating liquids.