Physical methods of water disinfection include. Water disinfection methods

04.10.2020

Water is an integral part of our life. Every day we drink a certain amount and often do not even think about the fact that disinfection of water and its quality is an important topic. And in vain, heavy metals, chemical compounds and pathogenic bacteria can cause irreversible changes in the human body. Today, serious attention is paid to water hygiene. Modern methods of disinfection of drinking water are able to cleanse it of bacteria, fungi, viruses. They will come to the rescue even if the water smells bad, has foreign tastes, color.

The preferred methods of quality improvement are selected depending on the microorganisms in the water, the level of contamination, the source of the water supply and other factors. Disinfection is aimed at removing pathogenic bacteria that have a destructive effect on the human body.

The purified water is transparent, has no foreign tastes and odors, and is absolutely safe. In practice, methods of two groups are used to combat harmful microorganisms, as well as their combination:

chemical;
physical;
combined.

In order to select effective disinfection methods, it is necessary to analyze the liquid. Among the analyzes carried out are:

chemical;
bacteriological;

The use of chemical analysis allows to determine the content of various chemical elements in water: nitrates, sulfates, chlorides, fluorides, etc. Nevertheless, the indicators analyzed by this method can be divided into 4 groups:

Organoleptic indicators. Chemical analysis of water allows you to determine its taste, smell and color.
Integral indicators are density, acidity and water hardness.
Inorganic - various metals found in water.
Organic indicators - the content in water of substances that can change under the influence of oxidants.

Bacteriological analysis is aimed at identifying various microorganisms: bacteria, viruses, fungi. Such an analysis identifies the source of infection and helps determine the methods of disinfection.

Chemical methods of disinfection of drinking water

Chemical methods are based on the addition of various oxidizing reagents to the water that kill harmful bacteria. The most popular among such substances are chlorine, ozone, sodium hypochlorite, chlorine dioxide.

To achieve high quality, it is important to correctly calculate the dose of the reagent. A small amount of a substance may not have an effect, but rather, on the contrary, contribute to an increase in the number of bacteria. The reagent must be injected in excess, this will destroy both existing microorganisms and bacteria that got into the water after disinfection.

The excess must be calculated very carefully so that it cannot harm people. Most popular chemical methods:

chlorination;
ozonation;
oligodynamia;
polymer reagents;
iodization;
bromination.

Chlorination

Chlorination water purification is a traditional and one of the most popular water purification methods. Chlorine-containing substances are actively used for the purification of drinking water, water in pools, and disinfection of premises.

This method has gained its popularity due to its ease of use, low cost, high efficiency. Most pathogenic microorganisms that cause various diseases are not resistant to chlorine, which has a bactericidal effect.

To create unfavorable conditions that prevent the reproduction and development of microorganisms, it is enough to introduce chlorine in a small excess. Excess chlorine contributes to the prolongation of the disinfection effect.

In the process of water treatment, the following chlorination methods are possible: preliminary and final. Pre-chlorination is used as close as possible to the place of water intake; at this stage, the use of chlorine not only disinfects water, but also helps to remove a number of chemical elements, including iron and manganese. Final chlorination is the last stage in the processing process, during which the destruction of harmful microorganisms by means of chlorine takes place.

Also distinguish between normal chlorination and overchlorination. Normal chlorination is used to disinfect fluids from sources with good sanitary performance. Overchlorination - in the case of severe water contamination, as well as if it is contaminated with phenols, which in the case of normal chlorination only aggravate the water condition. Residual chlorine in this case is removed by dechlorination.

Chlorination, like other methods, has its drawbacks along with advantages. Getting into the human body in excess, chlorine leads to problems with the kidneys, liver, gastrointestinal tract. The high corrosiveness of chlorine leads to rapid wear of the equipment. All kinds of by-products are formed during the chlorination process. For example, trihalomethanes (chlorine compounds with organic substances) can cause asthma symptoms.

Due to the wide application of chlorination, a number of microorganisms have developed resistance to chlorine, therefore, a certain percentage of water contamination is still possible.

Chlorine gas, bleach, chlorine dioxide and sodium hypochlorite are most commonly used for water disinfection.

Chlorine is the most popular reagent. It is used in liquid and gaseous form. Destroying the pathogenic microflora, eliminates unpleasant taste and smell. Prevents algae growth and improves fluid quality.

For purification with chlorine, chlorinators are used, in which gaseous chlorine is absorbed with water, and then the resulting liquid is delivered to the place of application. Despite the popularity of this method, it is quite dangerous. Transporting and storing highly toxic chlorine requires compliance with safety regulations.

Chlorine lime is a substance obtained by the action of gaseous chlorine on dry slaked lime. To disinfect the liquid, bleach is used, the percentage of chlorine in which is at least 32-35%. This reagent is very dangerous for humans, it causes difficulties in production. Due to these and other factors, bleach is losing its popularity.

Chlorine dioxide has a bactericidal effect, practically does not pollute the water. Unlike chlorine, it does not form trihalomethanes. The main reason that hinders its use is its high explosiveness, which complicates production, transportation and storage. At present, the production technology at the place of application has been mastered. Destroys all types of microorganisms. The disadvantages include the ability to form secondary compounds - chlorates and chlorites.

Sodium hypochlorite is used in liquid form. The percentage of active chlorine in it is twice that in bleach. Unlike titanium dioxide, it is relatively safe during storage and use. A number of bacteria are resistant to its effects. In case of long-term storage, it loses its properties. Available on the market in the form of a liquid solution with various chlorine contents.

It should be noted that all chlorine-containing reagents are highly corrosive, and therefore it is not recommended to use them to purify water entering water through metal pipelines.

Ozonation

Ozone, like chlorine, is a strong oxidizing agent. Penetrating through the membranes of microorganisms, it destroys the cell walls and kills it. both with disinfection of water and with its discoloration and deodorized. Capable of oxidizing iron and manganese.

Possessing a high antiseptic effect, ozone destroys harmful microorganisms hundreds of times faster than other reagents. Unlike chlorine, it destroys almost all known types of microorganisms.

When decomposed, the reagent is converted into oxygen, which saturates the human body at the cellular level. The rapid disintegration of ozone at the same time is also a disadvantage of this method, since after 15-20 minutes. after the procedure, the water can be re-contaminated. There is a theory according to which, when ozone is exposed to water, the decomposition of phenolic groups of humic substances begins. They activate organisms that were in hibernation until processing.

Saturated with ozone, water becomes corrosive. This leads to damage to water pipes, plumbing, household appliances. In the case of an incorrect amount of ozone, the formation of side elements that are highly toxic is possible.

Ozonation has other disadvantages, which include the high cost of purchase and installation, high electrical costs, as well as a high class of ozone hazard. Care and safety precautions must be taken when working with the reagent.

Ozonation of water is possible using a system consisting of:

an ozone generator in which the process of separating ozone from oxygen takes place;
a system that allows ozone to be introduced into water and mixed with liquid;
reactor - a container in which ozone interacts with water;
destructor - a device that removes residual ozone, as well as devices that control ozone in water and air.

Oligodynamia

Oligodynamia - disinfection of water by exposing it to noble metals. The most studied application of gold, silver and copper.

The most popular metal for the destruction of harmful microorganisms is silver. Its properties were discovered in antiquity, a spoon or a silver coin was placed in a container with water and the water was allowed to settle. The claim that this method is effective is controversial.

Theories of the effect of silver on microbes have not been conclusively confirmed. There is a hypothesis according to which the cell is destroyed by electrostatic forces arising between positively charged silver ions and negatively charged bacterial cells.

Silver is a heavy metal that, if accumulated in the body, can cause a number of diseases. An antiseptic effect can be achieved only at high concentrations of this metal, which is detrimental to the body. Less silver can only inhibit bacterial growth.

In addition, spore-forming bacteria are practically insensitive to silver; its effect on viruses has not been proven. Therefore, the use of silver is advisable only to extend the shelf life of initially pure water.

Copper is another heavy metal that can have a bactericidal effect. Even in ancient times, it was noticed that the water that stood in copper vessels retained its high substances much longer. In practice, this method is used in basic household conditions to purify a small volume of water.

Polymer reagents

The use of polymer reagents is a modern method of water disinfection. It significantly outperforms chlorination and ozonation due to its safety. The liquid, purified with polymeric antiseptics, has no taste or foreign odors, does not corrode metal, does not affect the human body. This method has become widespread in the purification of water in swimming pools. Water purified with a polymer reagent has no color, foreign taste or odor.

Iodination and bromination

Iodization is a disinfection method using iodine-containing compounds. The disinfecting properties of iodine have been known to medicine for a long time. Despite the fact that this method is widely known and several attempts have been made to use it, the use of iodine as a water disinfectant has not gained popularity. This method has a significant drawback, dissolving in water, it causes a specific smell.

Bromine is a fairly effective reagent that kills most of the known bacteria. However, due to its high cost, it is not popular.

Physical methods of water disinfection

Physical methods of cleaning and disinfection work water without the use of reagents and interference with the chemical composition. The most popular physical methods are:

UV irradiation;
ultrasonic exposure;
heat treatment;
electric pulse method;

UV radiation

The increasing popularity among the methods of water disinfection is gaining the use of UV radiation. The technique is based on the fact that beams with a wavelength of 200-295 nm can kill pathogenic microorganisms. Penetrating through the cell wall, they act on nucleic acids (RND and DNA), and also cause disruptions in the structure of membranes and cell walls of microorganisms, which leads to the death of bacteria.

To determine the radiation dose, it is necessary to conduct a bacteriological analysis of the water, this will reveal the types of pathogenic microorganisms and their susceptibility to rays. Efficiency is also affected by the wattage of the lamp used and the level of absorption of radiation by the water.

The dose of UV radiation is equal to the product of the radiation intensity and its duration. The higher the resistance of microorganisms, the longer they need to be exposed

UV radiation does not affect the chemical composition of water, does not form side compounds, thus excluding the possibility of harm to humans.

When using this method, overdose is not possible, UV irradiation is characterized by a high reaction rate, it takes several seconds to disinfect the entire volume of liquid. Without changing the composition of water, radiation can destroy all known microorganisms.

However, this method is not without its disadvantages. Unlike chlorination, which has a prolonged effect, the effectiveness of the irradiation is maintained as long as the rays are exposed to the water.

A good result is achieved only in purified water. The level of UV absorption is influenced by impurities in the water. For example, iron is able to serve as a kind of shield for bacteria and "hide" them from exposure to rays. Therefore, it is advisable to carry out preliminary water purification.

The UV system consists of several elements: a stainless steel chamber containing a lamp protected by quartz covers. Passing through the mechanism of such an installation, the water is constantly exposed to ultraviolet radiation and complete disinfection.

Ultrasonic disinfection

Ultrasonic disinfection is based on the cavitation method. Due to the fact that under the influence of ultrasound, sudden pressure drops occur, microorganisms are destroyed. Ultrasound is also effective for fighting algae

This method has a narrow range of uses and is at the stage of development. The advantage is insensitivity to high turbidity and color of water, as well as the ability to affect most forms of microorganisms.

Unfortunately, this method is only applicable for small volumes of water. Like UV radiation, it has an effect only in the process of interaction with water. Ultrasonic disinfection also did not gain popularity due to the need to install complex and expensive equipment.

Heat treatment of water

At home, the thermal method of water purification is the well-known boiling. The high temperature kills most microorganisms. Under industrial conditions, this method is ineffective due to its cumbersomeness, time-consuming and low intensity. In addition, heat treatment is not able to get rid of foreign tastes and disease-causing spores.

Electropulse method

The electro-pulse method is based on the use of electrical discharges that form a shock wave. Microorganisms die under the influence of water hammer. This method is effective for both vegetative and spore-forming bacteria. Able to achieve results even in muddy water. In addition, the bactericidal properties of the treated water are retained for up to four months.

The downside is the high energy consumption and high cost.

Combined methods of water disinfection

To achieve the greatest effect, combined methods are used, as a rule, reagent methods are combined with reagentless ones.

The combination of UV irradiation with chlorination has become very popular. So, UV rays kill pathogenic microflora, and chlorine prevents re-infection. This method is used for both drinking water purification and pool water purification.

For the disinfection of swimming pools, UV radiation is mainly used with sodium hypochlorite.

Chlorination at the first stage can be replaced by ozonation

Other methods include oxidation in combination with heavy metals. Both chlorine-containing elements and ozone can act as oxidants. The essence of the combination is that oxidants infect harmful microbes, and heavy metals make it possible to keep the water disinfected. There are other methods of complex water disinfection.

Household water purification and disinfection

It is often necessary to purify water in small quantities right here and now. For these purposes, use:

soluble disinfecting tablets;
potassium permanganate;
silicon;
improvised flowers, herbs.

Disinfectant tablets can help out in field conditions. Typically, one tablet is used per liter. water. This method can be classified as a chemical group. Most often, such tablets are based on active chlorine. The duration of the tablet is 15-20 minutes. In case of heavy contamination, the amount can be doubled.

If suddenly there were no tablets, it is possible to use ordinary potassium permanganate at the rate of 1-2 g per bucket of water. After the water has settled, it is ready to use.

Natural plants also have a bactericidal effect - chamomile, celandine, St. John's wort, lingonberry.

Another reagent is silicon. Place it in water and let it sit for 24 hours.

Sources of water supply and their suitability for disinfection

Water supply sources can be divided into two types - surface and groundwater. The first group includes water from rivers and lakes, seas and reservoirs.

When analyzing the suitability of drinking water located on the surface, a bacteriological and chemical analysis is carried out, the condition of the bottom, temperature, density and salinity of sea water, radioactivity of water, etc. An important role when choosing a source is played by the proximity of industrial facilities. Another stage in assessing the source of water intake is the calculation of the possible risks of water contamination.

The composition of water in open reservoirs depends on the time of the year; such water contains various contaminants, including pathogens. The highest risk of contamination of water bodies is near cities, factories, factories and other industrial facilities.

River water is very turbid, it is distinguished by its color and hardness, as well as a large number of microorganisms, the infection with which most often occurs from runoff waters. In water from lakes and reservoirs, blooms are often found due to the development of algae. Also such waters

The peculiarity of surface sources is a large water surface that comes into contact with the sun's rays. On the one hand, it contributes to the self-purification of water, on the other hand, it serves the development of flora and fauna.

Despite the fact that surface water can self-purify, this does not save them from mechanical impurities, as well as pathogenic microflora, therefore, during water intake, they are thoroughly purified with further disinfection.

Another type of water intake sources is groundwater. The content of microorganisms in them is minimal. Spring and artesian water is best suited to supply the population. To determine their quality, experts analyze the hydrology of the rock layers. Particular attention is paid to the sanitary state of the territory in the area of \u200b\u200bwater intake, since this depends not only on the quality of water in the here and now, but also the prospect of infection with harmful microorganisms in the future.

Artesian and spring water benefits from water from rivers and lakes, it is protected from bacteria contained in runoff waters, from exposure to sunlight and other factors that contribute to the development of unfavorable microflora.

Normative documents of water-sanitary legislation

Since water is the source of human life, serious attention is paid to its quality and sanitary condition, including at the legislative level. The main documents in this area are the Water Code and the Federal Law “On the Sanitary and Epidemiological Welfare of the Population”.

The Water Code contains rules for the use and protection of water bodies. Provides the classification of ground and surface waters, defines the penalties for violation of water legislation, etc.

The Federal Law “On the Sanitary and Epidemiological Welfare of the Population” regulates the requirements for sources, water from which can be used for drinking and housekeeping.

There are also state quality standards that determine suitability indicators and put forward requirements for the methods of water analysis:

GOST water quality

GOST R 51232-98 Drinking water. General requirements for the organization and methods of quality control.
GOST 24902-81 Water for household and drinking purposes. General requirements for field analysis methods.
GOST 27064-86 Water quality. Terms and Definitions.
GOST 17.1.1.04-80 Classification of groundwater by water use purposes.

SNiPs and requirements for water

Building codes and regulations (SNiP) contain rules for the organization of internal water supply and sewerage of buildings, regulate the installation of water supply systems, heating, etc.

SNiP 2.04.01-85 Internal water supply and sewerage of buildings.
SNiP 3.05.01-85 Internal sanitary systems.
SNiP 3.05.04-85 External networks and water supply and sewerage facilities.

SanPiNy for water supply

In the sanitary and epidemiological rules and norms (SanPiN), you can find what requirements for the quality of water both from the central water supply system and water from wells and wells exist.

SanPiN 2.1.4.559-96 “Drinking water. Hygienic requirements for water quality of centralized drinking water supply systems. Quality control."
SanPiN 4630-88 "MPC and TAC for hazardous substances in water of water bodies of household and drinking and cultural and household water use"
SanPiN 2.1.4.544-96 Requirements for the quality of water in decentralized water supply. Sanitary protection of sources.
SanPiN 2.2.1 / 2.1.1.984-00 Sanitary protection zones and sanitary classification of enterprises, structures and other facilities.

Water is a factor that directly affects the quality of human life. The mood of a person in the morning after washing depends on its color and smell, and the well-being and health of the body depends on the composition.

Water, being the basis of life, easily spreads infectious diseases. To prevent the transmission of pathogens through drinking water, liquid disinfection and disinfection are used. These processes eliminate fungi, bacteria, unpleasant taste and color, thus ensuring the safety of drinking water.

Purification and disinfection of drinking water for supply to residential buildings is carried out at water treatment stations of centralized water supply. There are also methods and installations for local use - in the form of small systems for treating water from a well or methods that allow you to purify water collected in a bottle.

Classification of water disinfection methods

To choose the right method of disinfection, analysis of contaminated water is carried out. The number and type of microorganisms, the degree of side contamination are investigated. The volume of water to be treated and the economic factor are also determined.

Purified water is clear and colorless, odorless and tasteless. To achieve this effect, the following groups of methods are used:

physical;
chemical;
combined.

Each group has its own distinctive features, but all methods in one way or another allow you to remove pathogenic microorganisms from the water. You can get detailed information on equipment for water purification and disinfection from the KVANTA + company in Tyumen.

The chemical method is working with reagents added to water. Physical disinfection is carried out through temperature or various radiation. Combined methods combine the work of these two groups.

The most effective ways

The infectious safety of water is an important and urgent problem, which is why many methods have been invented to get rid of water from microorganisms. Disinfection methods keep getting better. They are becoming more effective and accessible. In our time, the following methods are considered the best:

heat treatment using high temperatures;
ultrasonic treatment;
reagent methods;
ultraviolet irradiation of liquid;
high-power electrical discharges.

Physical methods of water disinfection

In front of them, the water must be cleaned of suspended matter and impurities. For this, coagulation, sorption, flotation and filtration are used.

This type of methods includes the use of:

ultrasound;
ultraviolet radiation;
high temperatures;
electricity.

Ultraviolet disinfection

The disinfecting effect of ultraviolet radiation has been known for a very long time. Its work is similar to sunlight, successfully destroying unadapted microorganisms outside the Earth's ozone layer. Ultraviolet light acts on cells, creating cross-links in DNA, as a result of which the cell loses its ability to divide and dies (Fig. 2).

The installation consists of lamps placed in quartz sleeves. The lamps produce a study that instantly destroys microorganisms, and the covers prevent the lamps from cooling. The quality of disinfection when using this method depends on the transparency of the water: the cleaner the incoming liquid, the further the light spreads and the less the lamp becomes dirty. To do this, before disinfection, the water goes through other stages of purification, including mechanical filters. The reservoir through which the water flows is usually equipped with a stirrer. Stirring the layers of liquid allows the disinfection process to proceed more evenly.

UV disinfection unit design

It is important to know that lamps and covers require regular maintenance: the structure must be disassembled and cleaned at least once a quarter.

Then the effectiveness of the process will not deteriorate due to the appearance of scale and other contaminants. The lamps themselves must be replaced once a year.

Ultrasonic disinfection units

The operation of such installations is based on cavitation. Due to the intense vibrations that water undergoes due to the high-frequency sound, numerous voids are formed in the liquid, it seems to "boil". An instantaneous pressure drop leads to rupture of cell membranes and the death of microorganisms.

Equipment for ultrasonic water treatment is effective, but requires high costs and competent operation. It is important that the personnel know how to handle the device - its effectiveness depends on the quality of the equipment setting.

Thermal disinfection

This method is extremely common among the population and is actively used in everyday life. With the help of high temperature, that is, boiling, the water is purified from almost all possible pathogenic organisms. In addition, the hardness of the water decreases and the content of dissolved gases decreases. The taste of the water remains the same. However, boiling has one drawback: water is considered safe for about a day, after which bacteria and viruses can settle in it again.

Boiling water is a reliable and simple method of disinfection

Electropulse disinfection

The technique is as follows: electrical discharges entering the water create a shock wave, microorganisms fall under a water hammer and die. This method does not require preliminary purification and is effective even with increased turbidity. Not only vegetative bacteria die, but also spore-forming bacteria. The advantage is the long-term preservation of the effect (up to 4 months), and the disadvantage is the considerable cost and high energy consumption.

Chemical methods of water disinfection

They are based on chemical reactions that take place between a contamination or microorganism and a reagent added to the fluid.

In chemical disinfection, it is important to control the dose of the reagent.

It must be accurate. Lack of substance will not be able to fulfill its purpose. In addition, a small amount of reagent will lead to increased activity of viruses and bacteria.

To improve the performance of the chemical, it is added in excess. In this case, harmful microorganisms die, and the effect persists for a long time. The excess is calculated separately: if you add too much, the reagent will reach the consumer, and he will be poisoned.

Chlorination

Chlorine is widespread and used in water treatment in many countries of the world. It successfully copes with any volume of microbiological contamination. Chlorination leads to the death of most pathogenic organisms and is cheap and affordable. In addition, the use of chlorine and its compounds makes it possible to extract metals and hydrogen sulfide from water. Chlorination is used in urban drinking water supply systems. It is also used in swimming pools where there are large numbers of people.

However, this method has several disadvantages. Chlorine is extremely dangerous, causes cancer and cell mutations, and is toxic. If the excess chlorine does not disappear in the pipeline, but reaches the public, it can lead to serious health problems. The danger is especially strong during transition periods (autumn and spring), when, due to an increase in the pollution of surface waters, the dose of the reagent is increased during water treatment. Boiling such water will not help to avoid negative consequences, but on the contrary, chlorine will turn into dioxin, which is the strongest poison. In order to allow the excess chlorine to evaporate, tap water is collected in large containers and left for a day in a well-ventilated area.

Ozonation

Ozone has a strong oxidizing effect. It penetrates into the cell and destroys its walls, leading to the death of the bacteria. This substance is not only a strong antiseptic, but also discolors and deodorizes water, oxidizes metals. Ozone works quickly and gets rid of almost all microorganisms in the water, overtaking chlorine in this characteristic.

Ozonation is considered the safest and most effective method, but it also has several disadvantages. Excess ozone leads to corrosion of metal parts of equipment and pipelines, devices wear out and break down faster than usual. In addition, the latest research notes that ozonation causes the "awakening" of microorganisms that were in a conditional hibernation.

Ozonation process diagram

The method is distinguished by the high cost of installation and high energy consumption. To work with ozone equipment requires highly qualified personnel, because the gas is toxic and explosive. To release water to the population, it is necessary to wait out the ozone decay period, otherwise people may suffer.

Disinfection with polymer compounds

No harm to health, destruction of odors, tastes and colors, long duration of action - the listed advantages relate to disinfection using polymer reagents. This type of substance is also called polymeric antiseptics. They do not corrode or damage fabric, do not cause allergies and are effective.

Oligodynamia

It is based on the ability of precious metals (such as gold, silver and copper) to disinfect water.

It has long been known that these metals have an antiseptic effect. Copper and its alloys are often used in the field when a small volume of liquid needs to be disinfected individually.

For a broader effect of metals on microorganisms, ionizers are used. These are flow-through devices operating on the basis of galvanic couples and electrophoresis.

Silver disinfection

This metal is considered to be one of the most ancient methods of water disinfection. In ancient times, it was believed that silver cures any disease. It is now known to negatively affect many microorganisms, but it is not known whether silver destroys the simplest bacteria.

This product has a visible effect on water purification. However, it negatively affects the human body when it accumulates in it. It is not for nothing that silver has a high hazard class. Disinfection of water with silver ions is not considered a safe method, and therefore is practically not used in industry. Silver ionizers are used on rare occasions in everyday life to treat small volumes of water.

Compact household water ionizer (silver ionizer)

Iodination and bromination

Iodine is widely known and used in medicine for a long time. Scientists have repeatedly tried to use its disinfecting effect in water treatment, but its use leads to an unpleasant odor. Bromine copes well with almost all known pathogenic microorganisms. But it has a significant drawback - high cost. Due to their disadvantages, these two substances are not used for the treatment of waste and drinking water.

Combined methods of water disinfection

Comprehensive methods rely on a combination of physical and chemical methods to improve performance. An example is a combination of ultraviolet radiation and chlorination (sometimes chlorination is replaced by ozonation). UV lamps kill microorganisms, while chlorine or ozone prevents them from reoccurring. In addition, oxidation and heavy metal treatments work well. An oxidizing reagent disinfects, and metals prolong the bactericidal effect.

Combination of UV disinfection and ultrasound action

How to disinfect water at home

There are five ways to quickly disinfect a small volume of water:

boiling;
adding potassium permanganate;
the use of disinfecting tablets;
the use of herbs and flowers;
infusion with silicon.

Potassium permanganate is added water in the amount of 1-2 g per bucket of water, after which the pollution precipitates.

Special tablets for the destruction of microorganisms are used to neutralize water from a well, well or spring. They are the most modern way, affordable, inexpensive and effective. Many tablets, such as the Aquatabs brand, can be used to clean large volumes of liquid.

If the water needs to be disinfected during the hike, you can use special herbs: St. John's wort, lingonberry, chamomile or celandine.

You can also use silicon: it is placed in water and left for a day.

Drinking water safety regulations

On the part of the state, water quality is strictly controlled by regulatory documents, rules and restrictions. The basis of legislative acts in the field of protection of water resources and quality control of the water used are two documents: the Federal Law “On the Sanitary and Epidemiological Well-Being of the Population” and the Water Code.

The first law contains requirements for the quality of water supply sources, from which water enters residential buildings and for the needs of agriculture. The second document describes the norms for the use of water sources and instructions for ensuring their safety, and also defines the penalties.

GOSTs

GOSTs describe the rules according to which the quality control of waste and drinking water must pass. They contain methods for conducting analyzes in the field, and also allow you to divide waters into groups. The most important GOSTs are presented in the table.

SNiPs

Building codes and regulations determine the requirements for the construction of water treatment facilities, for the installation of various types of pipelines and water supply systems. Information is contained in SNiPs under the following numbers: SNiP 2.04.01-85, SNiP 3.05.01-85, SNiP 3.05.04-85.

SanPiNy

Sanitary and epidemiological rules and norms contain hygienic requirements for the quality of various water groups, for the composition, for water intake facilities and the location of water intakes: SanPiN 2.1.4.559-96, SanPiN 4630-88, SanPiN 2.1.4.544-96, SanPiN 2.2.1 / 2.1 .1.984-00.

Thus, the effectiveness of disinfection of tap water is monitored regularly and in accordance with many rules and regulations. And a large number of different methods of fresh water disinfection allow you to choose the best option for any conditions. This makes properly treated and treated water safe for human consumption.

Water disinfection methods are classified into physical (non-reagent) and chemical (reagent).

Non-reagent disinfection methods water: boiling, treatment with ultraviolet (UV) radiation, gamma rays, ultrasound, high-frequency electric current, etc. Non-reagent methods have advantages, since they do not lead to the formation of residual harmful substances in the water.

Boiling within 30 minutes. used for local water supply causes only the death of vegetative forms, which occurs already at 80 0 C for 30 seconds, but also the spores of microorganisms.

Water disinfection shortwave UV radiation (l \u003d 250-260 nm) due to the photochemical cleavage of the protein components of the membranes of bacterial cells, vibrios and helminth eggs, it causes a rapid death of vegetative forms and spores of microorganisms, viruses and helminth eggs resistant to chlorine. Restriction - the method is not used for water with high turbidity, color, and containing iron salts.

Reagent disinfection methods water: treatment with silver ions, ozonation, chlorination.

Silver ion treatment leads to inactivation of enzymes of protoplasm of bacterial cells, loss of the ability to reproduce and gradual death. Silvering of water can be carried out in different ways: by filtering water through sand treated with silver salts; electrolysis of water with a silver anode for 2 hours, which leads to the transition of silver cations into water. The advantage of the method is long-term storage of silvered water. Restriction - the method is not used for water with a high content of suspended organic matter and chlorine ions.

Ozonation based on the oxidation of organic substances and other water pollution with ozone O 3 - an allotropic modification of oxygen, which has a higher oxidation potential and 15 times higher solubility. Ozone is consumed to a greater extent for the oxidation of organic and easily oxidized inorganic substances than for disinfection. The time required for ozone disinfection is 1-2 minutes. The applied dose of ozone is 0.5-0.6 mg / l. A prerequisite for ozonation is the creation of a residual amount of ozone in water (0.1-0.3 mg / l) to prevent the growth and reproduction of pathogenic microorganisms. The advantage of the method is the absence of residues, deodorization of water, removal of color, short reaction times and destruction of viruses. However, the method requires cheap sources of electricity, since the ozone-air mixture is obtained using an energy-intensive process - a "quiet" electric discharge on an ozonizer.

Chlorination - the most accessible and cheapest way of disinfection. Chlorinating agents are divided into 2 classes: 1) anion Cl - (gaseous Cl 2, chloramine, chloramines B and T, dichloramines B or T); 2) the so-called "active chlorine" - hypochlorite ion \u003d anion ClO - [calcium hypochlorite Ca (OCl) 2, sodium hypochlorite NaOCl, bleach - a mixture of calcium hypochlorite, calcium chloride, calcium hydroxide and water]. The bactericidal effect is explained by the action of hypochlorous acid formed by the reaction Cl 2 + H 2 O ® HOCl + HCl; active chlorine: HOCl ® OCl - + H + and hydrochloric acid HClO 2. The disinfection mechanism is associated with the interaction of active substances with SH-proteins of the bacterial cell wall. Disadvantages of the method: during chlorination, anthrax spores, tuberculosis pathogens, helminth eggs and larvae, cysts of amoeba and Burnet's rickettsia remain viable.

Disinfection of water by chlorination requires a preliminary experimental determination of the concentration of active chlorine in the chlorinating agent (normally 25-35%) and the chlorine absorption of water, which depends on the degree of water pollution by organic substances and microorganisms, for the oxidation and disinfection of which chlorine is consumed.

The conditions for effective chlorination are compliance with the duration of contact of the chlorine agent with water and its components (30 minutes in the warm and hot seasons, 60 minutes in the cold); creation of residual chlorine 0.3-0.5 mg / l. The chlorine absorption of water and the concentration of residual chlorine in total represent chlorine requirement water.

Restrictions on the use of water disinfection with preparations containing "active chlorine" applies to water contaminated with industrial wastewater containing phenol and other aromatic compounds, which requires "post-breakdown" chlorination, leading to the formation of chlordioxins - substances with high toxicity and cumulativeness in the human body. A sign of their formation is a strong "pharmacy" smell of water. To prevent the formation of chlorine dioxides during the chlorination of water polluted by industrial wastewater, gaseous chlorine is used frompreammonization(by preliminary treatment of water with ammonia).

If it is impossible to experimentally determine the chlorine absorption of water, use overchlorination method... Rechlorination is carried out with excessive doses of a chlorinating agent (usually in still water of a limited volume). When choosing a dose of active chlorine, the type and degree of water pollution in the water supply source and the epidemic situation in the territory of water collection in the source used are taken into account (usually the dose ranges from 10-20 mg of active chlorine per 1 liter of water)

Reagent (chemical) methods of disinfection of drinking water:

1. Chlorination
2. Ozonation
3. The use of heavy metals

Physical methods of disinfection of drinking water:

1. Boiling
2. Ultraviolet radiation
3. Disinfection by ultrasound
4. Radiation disinfection
5. Disinfection with ion exchange resins

Chlorination. A common and proven method of water disinfection is primary chlorination. It is this method that currently disinfects 98.6% of water. The primary reason for the success of this method is explained by the increased efficiency of water disinfection and the efficiency of the scientific and technical process in comparison with other methods. The chlorination method not only purifies water from unnecessary organic and biological impurities, but also safely removes salts of iron and manganese, and the advantage of this method is that this method retains the ability to ensure the microbiological protection of water during its transportation due to the aftereffect. disadvantages of this method. For example, after chlorination, free chlorine is present in water. This process takes up to several tens of hours in time. To eliminate impurities, additional purification of water on carbon filters is required. ? For the chlorination of water, drugs are used: as directly chlorine (aqueous or gaseous), chlorine dioxide and other chlorine-containing drugs.

Ozonation. The superiority of ozone (O3) over other disinfectants is contained in its inherent disinfecting and oxidizing properties due to the release of energetic atomic air upon contact with organic objects, destroying the enzyme systems of microbial cells and oxidizing any compounds that give water an annoying aroma. In addition to the unique ability to eliminate microbes, ozone has the highest efficiency in eliminating spores, cysts and many other pathogenic bacteria. The amount of ozone, which is important for the disinfection of drinking water, depends on the degree of water contamination and is 1-6 mg / liter. upon contact in 8-15 minutes; residual ozone should be less than 0.3-0.5 mg / liter. From the hygienic point of view, water ozonation is the best method for disinfecting drinking water.

The reasons for the slow spread of ozone technology are considered to be the high cost of equipment, high electricity consumption, high production costs, and the need for highly qualified equipment. Also, during operation, it was found that in different temperature modes, for example, if the temperature of the treated natural water is above 22 ° C), the ozonization process cannot achieve the required microbiological indicators due to the inaccessibility of the result of the disinfecting action? The method of water ozonization is technically laborious and the most expensive in contrast to other methods of disinfection of drinking water. This all limits the implementation of this method in daily life. Another significant flaw in ozonation is the toxicity of ozone.

The use of heavy metals. The use of heavy metals (copper, silver, etc.) for the disinfection of drinking water is based on the use of their "oligodynamic" quality - the ability to have an antibacterial effect in small concentrations. These alloys can be introduced in the form of salt solutions or by chemical dissolution. Both methods are likely to indirectly control their content in water. Also, the methods of disinfection of drinking water include the widely used method at the beginning of the last century - disinfection with bromine and iodine compounds, by the way, this method is more effective than chlorine and has better antibacterial qualities than chlorine, although the technology is more laborious. In modern practice, specialized ion exchangers enriched with iodine are usually used to disinfect drinking water by iodization. When water is passed through the ion exchanger, iodine is gradually washed out from the ion exchanger, providing the required dose in the water. This solution is suitable for compact personal installations. The disadvantage of this method is considered to be a change in the concentration of iodine during the period of work and the absence of complete control of its concentration.

Boiling. Of the physical methods of water disinfection, the most popular and correct is considered boiling.? When boiling most bacteria, microbes, bacteriophages, viruses, antibiotics and other biological objects that are located in open water sources and, as a result, in central water supply systems are destroyed. Also, for boiling dissolved gases are removed from the water and the water becomes softer. Taste properties of water at boiling change little. For good disinfection, it is recommended to boil the water for 15 - 20 minutes, since for a short time boiling the smallest organisms still have a chance to remain viable. But using boiling on an industrial scale is not feasible due to the high cost of the process.

Ultraviolet radiation. UV radiation is a promising industrial method of water disinfection. The disinfecting properties of this light are due to a special effect on cell metabolism, as well as on the enzyme systems of the bacterial cell. As a result, antibacterial light destroys vegetative and spore forms of microbes. The installations themselves are chambers made of stainless steel with UV lamps placed inside, protected from contact with water by transparent quartz covers. Water, passing through the disinfection chamber, is constantly exposed to ultraviolet irradiation, which kills all the smallest organisms in it.

Secondary toxins are not generated during UV irradiation, and therefore there is no upper threshold for the dose of UV irradiation. By increasing the dose of UV radiation, it is almost always possible to achieve the desired level of disinfection.

Also UV irradiation does not impair organoleptic qualities water, in consequence of this, this method can be attributed to environmentally friendly methods of water treatment. But even this method has disadvantages. UV treatment does not provide a prolonged action, unlike the ozonation method.

For personal water supply, UV installations are considered more promising.? Also with UV radiation, reactivation of microorganisms and even the development of new strains resistant to radiation damage is possible. The organization of the UV disinfection process requires more investments than the chlorination method, but less than the ozonation method. Low operating costs make UV disinfection and chlorination relatively inexpensive ways to purify water. Electricity consumption is negligible, and the annual lamp replacement costs a maximum of 10% of the installation cost.

Disinfection with ultrasound. This method of water disinfection uses ultrasound. The mechanism of action of ultrasound has not yet been fully understood. There are some assumptions: ultrasound causes the formation of voids, this leads to the rupture of the cell walls of bacteria ;? ultrasound causes the release of gas dissolved in water, and gas bubbles trapped in the bacterial cell cause cell rupture.? The superiority of the use of ultrasound over other methods of wastewater disinfection is its insensitivity to such moments as high turbidity and color of water, the number of microorganisms and the presence of dissolved substances in water.? The only moment that has a great influence on the disinfection of wastewater by ultrasound is the intensity of ultrasonic vibrations. The bactericidal effect of ultrasound of various frequencies is very significant and depends on the intensity of sound vibrations.

Disinfection and purification of water by ultrasound is considered one of the most modern methods of disinfection. Ultrasonic exposure is not often used in filters for disinfection of drinking water, however, the effectiveness of this method indicates the prospects of the method of disinfection of water by ultrasound, even despite its high cost.

Radiation radiation. There are proposals for the use of gamma radiation for disinfecting water.? Gamma installations operate in the following way: when water enters the cavity of the mesh cylinder of the receiving and separating unit, the solid inclusions move upward with the auger, then they are squeezed out in the diffuser and go into the hopper - collection. Then the water is diluted with pure water to a certain concentration and supplied to the unit of the gamma installation, in which, under the influence of the gamma radiation of the Co60 isotope, the disinfection process itself begins. Gamma radiation has a depressing effect on the activity of microbial enzymes. With large portions of gamma radiation, most of the causative agents of such dangerous diseases as poliomyelitis, typhus and others die.

Using ion exchange forces. Another physicochemical method of water disinfection through the introduction of ion exchange resins. G. Gillissen (1960) demonstrated the ability of anion exchange resins to release liquid from coli category microbes. Resin regeneration is likely. EV Shtannikov (1965) established the probability of water purification from microbes by ion-exchange polymers. Taking into account the opinion of the creator, this result is associated with the sorption of the virus and with its denaturation using an acidic or especially alkaline reaction. Another work by Shtannikov describes a method for disinfecting water with ion-active polymers, where the botulism toxin is located. Disinfection occurs through the oxidation of toxin and its sorption. In addition to these factors, the possibility of water disinfection by high-frequency currents and magnetic treatment was studied. disinfection water disinfection ozonation

What is meant by disinfection of drinking water? This is understood as a series of measures aimed at completely or partially eliminating viruses and bacteria in the water that can cause many infectious diseases.

But it should be understood that the complete purification of water from all bacteria will make it unsuitable for use with food. That is why one should be very careful about both the choice of a specific disinfection method and the conduct of a chemical and biological analysis of a water sample. There are several methods of exposure to harmful microorganisms:

Chemical or reagent;
Physical or non-reagent;
Combined.

Microorganisms

Each of these methods allows you to get rid of any harmful microorganisms in a certain way. For example, chemical methods work with the help of special coagulants-reagents, which are added to water precisely for the purpose of disinfection. This chlorination, ozonation, the use of sodium hypochlorite, silver, silicon and many other substances that help either get rid of "pests", or at least slow down their reproduction. Reagent-free methods - water disinfection using a physical reagent-free effect on the liquid. These are UV radiation, electrical impulse disinfection and other similar methods.

Combined methods are used using both physical and chemical effects alternately. This approach to disinfection is most effective and, as a rule, allows you to achieve not only complete disinfection of the liquid, but also to prevent the secondary growth of bacteria and viruses in water. In addition, the use of several methods also allows you to clean it from other contaminants.

Chemical disinfection of water

These include the treatment of liquids with oxidizing coagulants: ozone, sodium hypochlorite, chlorine and others. Among them are heavy metal ions. In order to achieve the most persistent disinfection effect by this method, you need to be able to determine the dose of the reagent that you will inject as accurately as possible, and then ensure the necessary period of time for water to contact the substance.

The dose is determined by calculation methods, as well as by trial disinfection. It is noteworthy that it is very important to accurately calculate the dose. Since a small dose may not only not work, but also ensure the rapid growth of the number of bacteria in the solution. An example of such an effect can be considered ozone, which in small quantities kills some bacteria, forming special compounds that awaken previously dormant bacteria and create ideal conditions for reproduction.

In order to provide a long-term effect, the dose of the reagent is calculated, as a rule, with an excess, which is guaranteed to destroy microorganisms in the water, and in the period after disinfection of the water will not allow them to multiply.

But the excess should be exactly such that disinfection occurs, but at the same time people who consume water as a drink did not get poisoned, since most of the reagents are quite toxic and can form persistent mutagenic and carcinogenic compounds.

Chlorination

Despite the presence of many modern methods of water purification and disinfection, chlorination continues to be used in water supply practice in our country. This is explained by the ease of use, maintenance, as well as high efficiency and, of course, the low cost of the reagent. An important plus in the application of this method is, first of all, its aftereffect. Even with a slight excess of chlorine (for example, water contains about 0.5 mg / l of residual chlorine), the growth of microorganisms does not occur again.

But this method has its drawbacks. Chlorine during oxidation has a very high degree of mutagenicity, toxicity, carcinogenicity. Even the following water purification with activated carbon does not completely remove the compounds formed in the chlorination process. They are quite persistent and highly pollute drinking water. Then, as a result, the effluent flows into the rivers, and then the toxic substances go downstream. Therefore, while the search is underway for reagents that will have a good ability to disinfect drinking water, while carrying fewer "side effects" during use.

So far, the most positive reviews have been achieved by the use of chlorine dioxide, which has a much higher ability to act on viruses and bacteria than that of simple chlorine. The same reagent has an order of magnitude less water pollution. However, chlorine dioxide is quite expensive and needs to be produced immediately on site. In addition, its prospects do not extend beyond small installations with low productivity.

They are used for chlorination with chlorine, bleach and other derivatives of the element. In addition to the main function (meaning disinfection), chlorine also helps to monitor the smell, taste, prevents the growth of algae, maintains the cleanliness of filters, removes manganese, iron, destroys hydrogen sulfide, discolors, etc.

The risk of chlorine use is largely associated with the formation of trihalomethanes. Methane derivatives in any form have a strong carcinogenic effect on the human body, thereby promoting the growth of cancer cells. It is noteworthy that boiling chlorinated water, which many consider a way out of this situation, only aggravates the situation, since under the influence of high temperatures, a very strong poison called dioxin is formed in chlorinated water.

Studies show that chlorine and its other derivatives cause diseases of the gastrointestinal tract, liver, cardiovascular system, as well as hypertension, atherosclerosis, various types of allergies, affect the skin and hair. Chlorine breaks down protein in the body.

Many people believe that as little harmful compounds as possible are formed after chlorination, water should be pre-purified from various impurities, since compounds are formed due to the interaction of chlorine with organic substances dissolved in the liquid.

Ozonation

Ozonation of a liquid makes it possible to decompose ozone particles in solution, thus forming atomic oxygen. It allows you to destroy the enzyme system of the microbial cell and oxidize some of the compounds that can give the water a rather obtrusive unpleasant odor. This method requires accurate calculations, since an unpleasant odor may appear in the water with an excess of ozone. In addition, too much ozone can accelerate metal corrosion. This affects not only the water supply system, but also household appliances and utensils that come into contact with this water.

From the point of view of hygiene, this is the best chemical method that can provide the fastest possible and, which is extremely important, safe for humans and the surrounding world, disinfection of water without the subsequent formation of carcinogenic, highly toxic compounds. But this method requires an impressive power consumption, the operation of complex equipment, and highly qualified service. Therefore, this method works as efficiently as possible mainly in centralized water supply systems. It is worth mentioning that it is quite expensive to use.

The gas itself is quite dangerous in the production process, toxic and even explosive. Many companies offer stationary installations for cottages, but it should be understood that without qualified maintenance and control systems, such devices can poison the air and water and, as a result, the owners. There is also always a risk of an explosive situation in such an installation.

According to some data, after ozonation, a secondary growth of the number of bacteria can occur. This is due to the fact that after such treatment of water, the decomposition of phenolic groups of humic substances begins. And they contribute to the activation of other microorganisms that were in a "dormant" state before processing. Therefore, there is no need to wait for 100% high quality ozone removal. But, unlike chlorine, ozone is hazardous to the first category. Also, due to the effect of ozone on metals (corrosion), it is necessary to wait for the ozone decay period before the treated water is piped. An exception may be the transportation of freshly treated water from some types of plastic, concrete, asbestos cement and other similar materials.

Polymer reagents / antiseptics

A separate reagent method of water purification is disinfection with polymeric reagents, which belong to the class of polymeric antiseptics. The most famous representative of this class is Biopag. When compared with chlorine and ozone, this drug is not harmful to health, does not have a local irritant effect on mucous surfaces and skin, and does not cause allergic reactions. Also among the advantages: lack of smell, color, taste in water at the end of the purification process, no corrosive effect on metals and harm to swimwear. The use of such antiseptics is extremely simple, but despite this, they have a long-term disinfection effect. This type of water disinfection is used most often in public swimming pools.

Other reagents

Also in reagent methods, various compounds of heavy metals, iodine, bromine, etc. are used. But they require certain knowledge in the application and the accuracy of the calculations. On the other hand, they are used to disinfect drinking water much more efficiently and with better quality. Disinfection with heavy metal ions is often isolated as a separate method - oligodynamic water disinfection. The most commonly used ions are noble metals. Silver is a prime example. But you need to understand that it does not remove from the water, but only inhibits the growth of bacteria for the duration of the action. In addition, this method requires a certain amount of the specified substance. Silver quickly accumulates in the body, but it is excreted very hard and slowly.

Other reagents that are not commonly used include strong oxidizing agents such as sodium hypochlorite. This particular reagent is used in cases where the water parameters are rather unstable and often change. The indication for use may be the presence of plankton in the liquid, organic substances that affect the degree of color of water. The use of sodium hypochloride, which is obtained by electrolysis of 2-4% sodium chloride solutions (this is a simple table salt) or mineralized waters, is considered one of the most promising and safe methods for water purification for humans and the environment. In its chemical and bactericidal action, sodium hydrochloride is identical to dissolved chlorine, but at the same time it has a long-term effect and is more safe for health. It is also safer for the environment.

Among the disadvantages should be highlighted: increased consumption of the reagent due to the low degree of its conversion. The rest remains in the water "ballast", increasing the salt content in the solution. Reducing the amount of salt after disinfection often requires a much larger amount of consumed energy and consumption of anode material. And this is much more expensive than chlorination.

Physical disinfection of water

Physical methods include those methods that affect the liquid with UV rays, ultrasound and other processes. First, preliminary purification is carried out: the water is filtered and coagulated. This helps to remove suspended particles, an impressive part of microorganisms in the liquid, helminth eggs.

During the application of ultraviolet radiation, a certain amount of energy must be supplied to the available volume of water. Its amount is calculated as follows: the radiation power, which is multiplied by the contact time. In this case, the contamination of water by bioorganisms should be determined. In this case, the number of microorganisms is calculated per 1 ml of liquid. Also, the presence of indicator bacteria in the water is determined, which are referred to the group of E. coli (in the abbreviation BGKP). E. coly - its main representative - is defined quite simply.

In general, you should be aware that HBCs are present in water that is contaminated with faeces. These organisms have the highest resistance to decontamination processes. E.coly is the most harmless of the group and helps to identify bacterial contamination in water. According to SanPiN 2.1.4.1074-01, the total number of bacteria should not exceed 50 per 100 ml of colyphoma bacteria.

But this norm cannot always be correlated with the disinfection of water from viruses. So, for example, ultraviolet radiation and chlorine separately provide different levels of water purification and disinfection according to the coli-index. Thus, UV rays have a better effect on bioorganisms than chlorine. But ozone will be approximately equal to UV rays according to the results of cleaning.

UV water treatment

UV rays can affect cell metabolism, the enzyme systems of bacterial cells. They destroy vegetative and, importantly enough, spore bacteria, which are difficult to destroy. The organoleptic properties of water do not change. This type of treatment cannot affect the formation of toxic substances, and therefore there is no upper dose threshold either. Accordingly, by increasing the dose of UV radiation, you may well be able to achieve the best results of water purification and disinfection. But this method also has a drawback - the complete absence of aftereffect. Still, such processes require from the customer capital investments in the field: much larger than with chlorination, but significantly less than with ozonation. Therefore, for individual use, such installations will be the best option, since smaller devices will come out at a cost price approximately at the level of chlorination, only with all the ensuing advantages of this type of water disinfection.

Most often, one factor can reduce the efficiency of such an installation: contamination of quartz lamps with mineral deposits of salts, which are based on a mineral-organic composition. This issue is solved simply - either food acids are added to the water (vinegar does an excellent job with this problem), circulating through the installation, or the surface of the lamps is mechanically cleaned.

Disinfection with UV radiation is carried out only after preliminary water purification, since the contaminants present in the water can simply nullify the whole process by screening UV rays. The most optimal wavelength is 200-295 nm. The most effective is the "golden mean" - 260 nm. This level of radiation actively destroys the cytoplasm of cells, affecting protein colloids.

Ultraviolet radiation is, without exaggeration, the most effective method of water disinfection today. This tool belongs to the invisible short-wave part of the spectrum. The service life of a UV lamp is several thousand hours on average.

Disinfection with ultrasound

Disinfection of water using ultrasonic equipment is based on the ability of certain sound frequencies to cause cavitation, i.e. form voids that create a large difference in pressure. Such a dissonance leads to rupture of the cell membranes and the subsequent death of the bacterial cell. The level of bactericidal action depends on the intensity of sound vibrations. But these installations require certain equipment, qualified maintenance, and they are also quite expensive.

Ultrasound is produced by a generator - magnetostrictive or piezoelectric. In order for disinfection to be carried out as efficiently as possible, a sound frequency of 48 thousand Hz is created. Speaking about the effectiveness of ultrasound, it is worth mentioning the following fact: the frequency of 20 thousand Hz allows cutting metals and even processing diamonds. But at a low frequency, ultrasound can provoke an increase in the number of bacteria in the water. Therefore, the knowledge of the ongoing processes and maintenance of expensive equipment should be mandatory for the user of such an installation.

Boiling

But the most popular and widespread physical method among the people will remain for a very long time boiling water, which gives the highest possible results: almost all harmful bacteria, bacteriophages, viruses, antibiotics and many other biological objects are destroyed. The gases dissolved in the liquid are also eliminated and the pH (hardness) of the water is noticeably reduced. The taste of water does not undergo a strong change.

Caricature of water purification methods

For many cases, it is the integrated approaches to water disinfection that will be the most effective. This refers to the use of reagent-free and reagent methods. An example would be UV disinfection and subsequent chlorination. Thus, not only harmful microorganisms are eliminated, but also the absence of secondary biocontamination will be guaranteed. It is noteworthy that such a combined approach will allow not only to destroy microorganisms in water, but also to reduce the content of reagents. This will not only save money on reagents, but generally improve the condition of the water itself.

Ozonation followed by chlorination is also often used. Due to this, in principle, secondary bioinfection should not occur. The formation of toxic chlorine-containing compounds in water also sharply decreases after the procedure.

It is worth mentioning this method of water disinfection and purification, as filtration. But in this case, complete cleaning will be possible only when the filter elements have cells smaller in size than the filtered microorganisms, which is approximately 1 micron. Even so, only bacteria can be removed from the water in this way. Viruses are known to be much smaller. For such cases, filters with pores of 0.1-0.2 microns are used.

A new filtration system called "Purifier" is gradually gaining popularity. According to manufacturers, such water purification is quite effective, since the device uses several water disinfection systems. The most common purifiers are those that use the most efficient filtration system.

This unit is a water purifier and heater with subsequent delivery. Some models can not only heat water up to 95 degrees, but also cool up to 4 degrees. The unit is connected to pipes with cold water supply using a special plastic tube, which is laid under the suspended ceiling, plinth or cable channel.

This unit is designed for offices or home use. The manufacturer also states that the water thus obtained will be much cheaper than bottled water. It is difficult to confirm or deny this fact, since the statistics of application have not yet been announced in domestic spaces.

New ways to disinfect water

Recently, there are "younger" methods of water purification and disinfection: electro-pulse and electrochemical. The most prominent domestic representatives of this technique are "Sapphire", "Emerald", "Aquamarine". They work using a diaphragm electrochemical reactor through which water is passed. The reactor is divided by a cermet membrane with the ability to conduct ultrafiltration into the anodic and cathodic regions. When current is applied to the cathode and anode chambers, acidic and alkaline solutions begin to form in them, and then electrolytic formation (which is also called active chlorine). In such an environment, almost all harmful microorganisms die pretty quickly, and some compounds that are dissolved in water are also destroyed.

The performance of such an apparatus generally depends on the design of the flow element and a certain number of elements. Anolytes and catholytes can also be used in separate units. They are most often used in the medical field. But it should be understood that water is only disinfected and purified. Manufacturers' statements that the resulting solution becomes miraculous and healing due to a change in the structure is just an advertising stunt. This method is called ECA technology.

Electric impulse action means an electric charge in water, which causes a certain degree of ultra-high pressure shock wave, then light radiation and, as a result, the formation of ozone, which, as we have already learned earlier, is extremely destructive for microorganisms and biological objects in water generally. This method of liquid disinfection, with proper maintenance of the device and carrying out all procedures, will help to make the water as clean as possible, and thanks to the generated ozone, some pollutants will be eliminated from the disinfected liquid.

But the above new methods of influencing microorganisms in a domestic environment cannot be applied due to the complexity of the ongoing processes and the necessary knowledge that will need to be applied in practice. In addition, such equipment will require a substantial investment.

It is worth mentioning that initially, sanitary standards do not imply the complete destruction of all harmful microorganisms that are in the water. The purpose of disinfection was actually the removal or inactivation of the bacteria, viruses and other biological elements most dangerous to human health, since completely sterile water can harm human health.

Considering the need to purify water primarily for human health, it is worth choosing the most optimal disinfection options. But before making any decisions, it is necessary to determine the level of water pollution not only by biological and mineral compounds, but also by microorganisms. Correct identification of the reasons will help you choose the most correct option.