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Water and methods of its purification One of the most important questions of the entire "water" chain is where the water comes from before it gets into the water pipes and then into the homes of consumers. Sources are divided into two main categories – open and underground. A big disadvantage of open sources is that they are more susceptible to external influence. Along with rain and meltwater, a variety of chemical components – from manure to engine oil-are washed into rivers and lakes. Industrial effluents also often fall there. Underground springs can also depend on this factor, but much less, and this is their advantage. The Belgorod region does not take water for water supply from surface sources. We have enough underground water. As a rule, these are deep artesian wells. The water in them is protected from contamination in 99 % of cases. To minimize the possibility of poor-quality water consumption by residents of the region, specialized structures control its quality. Experts take samples at several points in the water supply systems of localities. These are sources (wells), reservoirs (water towers), and distribution networks. The analysis allows you to understand at what stage on the way to the consumer the water may be contaminated. As a rule, the samples taken are within the norms approved by law. Tap water in the Belgorod region meets the requirements of sanitary regulations. You can drink tap water here. If inconsistencies are identified somewhere, they are quickly resolved. Employees of the regional center for hygiene and epidemiology report quarterly on studies of drinking water for sanitary, chemical, and microbiological indicators. Samples are taken from all sources and water pipes. Even water from wells is being investigated. Water may be contaminated with: • And many other elements, the presence of which is permissible only in small doses of mg/l. Impurities are divided into several groups: 1. Mineral-particles of soil, slags, clay, sand. the water contains mineral compounds of salts, acids, and bases. 2. Organic of natural origin-remains of plants and animals, products of their decay and physiological secretions. 3. Biological-microscopic algae, silt particles, fungi. This is an aquatic microflora. Microfauna is represented by microorganisms (plankton): crustaceans, worms, infusoria. 4. Organic artificial origin-impurities that enter the water as a result of the activities of industrial enterprises. according to the state, impurities can be: dissolved (invisible), liquid (emulsified), solid (visible particles), gaseous (nitrogen, carbon dioxide, oxygen are usually present in water). The exact composition of the aqueous solution can be determined by ordering an examination in a certified laboratory, where there is the necessary equipment, tools, reagents for research. the analysis of samples determines: total hardness, acidity and alkalinity (ph), numerical values of the presence of different components: calcium, sodium, strontium. What methods are the technologies for water purification based on The water treatment process includes different methods: 1. Physical-removal of large particles that are captured by coarse filters. 2. Chemical-elimination of impurities and gases with the help of chemically active substances-reagents. 3. Physico-chemical-complex methods, which provide for coarse and fine filtration. 4. biological (sanitary, bacteriological) - removal of living microorganisms by decontamination. Technological processes for water purification are developed taking into account the initial composition of aqueous solutions, their purpose, and application features. What are the existing technologies for water purification All modern technologies for water purification by the type of methods on which they are based can be divided into 4 groups: Physical methods-mechanical water treatment This is the primary technology of water treatment, which is used at the initial stage for cleaning from coarse-grained substances: 1. straining - a "home" or folk method in which water under the influence of its weight is decanted through layers of fabric, fine-mesh nets or grids. All insoluble garbage remains on the surface of the "filter bags", the clean liquid enters the prepared container, above which the garbage collection material is placed. So you can clean rain or spring water, which was attacked by litter. 2. Filtration - a more advanced process of water treatment, in which specially designed porous filters with cells of a certain size are used to trap various impurities. h2o molecules pass through the pores, deposits are washed off from mechanical filters of repeated use. 3. Settling - when the water is in a calm state, the suspended particles under their own weight settle down, forming a sediment. the water is carefully drained, the deposits are removed. With this method of cleaning, large settling tanks are used, in which water is settled, and containers where the purified solution enters. 4. UV disinfection-treatment of pre-purified water from large fractions with UV rays with a wavelength in the range of 200-400 nm for the purpose of disinfection. This method does not change the composition and physical properties of the liquid. using simple "folk" methods, it is easy to remove large specks, but it is impossible to remove dissolved impurities and microorganisms - they remain in the water. In industry and the national economy, these methods are used in the primary or intermediate stages of treatment, they are based on the main processes in large-scale water treatment. Especially widely used in everyday life and in production is filtration with various mechanical filters. New chemical technologies for water purification Chlorination, which has long been used to decontaminate water, is being replaced by ozonation and more productive methods, including effective modern methods: 1. De-ironization and aeration is a technology for removing ferrous impurities under the influence of air. Dissolved iron salts are converted into a visible precipitate, trapped by filters and removed from the system. 2. Sorption water purification by filters - the process proceeds with the use of absorbent sorption substances (aluminosilicates, charcoal). With their help, organic impurities are removed. 3. Softening on ion exchange filters - reducing the stiffness on ion exchange installations. Many industrial enterprises use this technology of underground water treatment, buying industrial ion exchange modular units from our company. 4. Electrodialysis and electrodeionization - under the action of an electric current, free salt ions completely dissolved in water are captured by an ion-exchange resin. They are easily replaced by hydroxyl group anions and hydrogen cations. The hydroxyl precipitate and can be removed easily. 5. Coagulation (treatment with reagents) - technology of water purification from surface sources with the use of special coagulants, with the help of which the particles of impurities are enlarged, captured by filters. The use of environmentally friendly resins allows the use of new, absolutely safe technologies in water treatment. These methods are based on chemical reactions of oxidation, neutralization, and reduction. Advanced complex physical and chemical methods In different countries of the world, including Russia, water treatment technology is constantly being improved. New methods are being developed that provide high-quality results in the intermediate and final stages of cleaning: 1. Reverse osmosis system-the use of porous membranes and sequential multi-stage cleaning. The technology used in reverse osmosis plants allows you to remove up to 99% of impurities, giving out absolutely clean, demineralized water at the output. 2. nanofiltration - baromembrane technological processes in water purification, in which the liquid is divided into two streams by a membrane partition, like reverse osmosis. The membrane traps microscopic organisms and suspended impurities. the purified stream is fed for use; the concentrate containing the sediment is flushed into the drain. the composition of the salts does not change, the color and turbidity decrease. 3. Distillation-industrial membrane filters for water purification by distillation and deionization technology allow you to get a pure distillate of high quality. This method is used to remove impurities from water intended for biotechnologies, laboratories, electronics, and to power devices that are particularly sensitive to hardness salts. 4. Ultrafiltration-the principle is based on the pressure drop when water passes through hollow fiber membranes. After filtration, the purified liquid enters the storage tank. To make the membranes less polluted and not so quickly fail, filters for mechanical cleaning of debris are built into the water solution supply line. 5. Flotation-innovative technologies in water treatment are designed specifically for wastewater. during flotation, water is purified from oil, oils, emulsified liquid impurities, and radioactive solutes. Under the influence of air and other inert gases that are passed through the water column, the resulting bubbles push impurities to the surface, which are removed by mechanical means. The technique laid down in the basis of the method can be used as a technology for cleaning recycled water. Sanitary and biological methods Developed processes that are aimed at the destruction of microbes, bacteria and other microorganisms. These are new technologies in water treatment: 1. Decontamination - a physical method in which exposure is performed using devices: sterilizers and lamps with UV radiation. With the non-contact method, only the pathogenic environment is destroyed, but the organoleptics of water - color, smell, taste, transparency-do not change. The effect of disinfection is given by all membrane filters: reverse osmosis, nano-and ultrafiltration. 2. Ozonation - short-term exposure. based on the calculations of the initial composition and the choice of effective cleaning methods, the exact dose of ozone is selected, which does not change the smell of the liquid at the outlet of the installation. the method is used for water treatment of drinking water at housing and communal facilities, for bio-purification of solutions used for agricultural and industrial needs. The process is eco-friendly and low-cost. biotechnological water treatment processes are applied at the final stages before being fed into the system for drinking use. One of the most difficult, "muddy" topics is the chemical composition of the water we drink. The fact is that it can vary greatly depending on the place where the water is taken. Individual characteristics of water can be at each source, at each well. They differ in depth. This means that the composition of the ground layers through which they pass However, there are also General signs that are characteristic of water over a relatively large area. However, there are also General signs that are characteristic of water over a relatively large area. According to doctors, our (Belgorod) water can not be characterized unambiguously. It has both pros and cons. The water that we get out of the ground has both positive and negative properties. For example, it is neutral in terms of alkaline parameters. It does not acidify or alkalize the body. It's good. The bad thing is that it has a lot of calcium and iron. The complexity of the situation with calcium is that it can be present in various States in water. First, this substance can be dissolved in water in the form of chalk. It is safe for a person, because chalk is not deposited in the internal organs. Ionized calcium is another matter. It is also quite a lot in our water, and it is he who, if several factors coincide, can play a bad role for the health of the consumer. Nevertheless, with the excess of calcium can be overcome. The molecules of this substance are quite large, so they can be easily eliminated using a filter. With a high iron content, they also fight with the help of special equipment – de-Ironing stations. They are located at the point where water enters the water supply system. Their installation is standard for the Belgorod region. The de-iron station is designed for water purification from excess iron, hydrogen sulfide, manganese and other elements by oxidation of iron from divalent 2+ to trivalent 3+, followed by filtration of the sediment. The task of the equipment is to transfer iron from the dissolved state to the undissolved state, which will then precipitate and be delayed by a special filter loading of the applied water filter.
 * Sulfates - salts of sulfuric acid.
 * Chlorides - compounds of hydrochloric (hydrochloric) acid.
 * nitrates - salts of nitric acid, which in large quantities penetrate into the soil from nitrogen fertilizers.
 * fluorides - solid compounds of hydrofluoric acid.
 * ferrous impurities, together with which undesirable manganese is often present.

The iron content in purified water should not exceed 0.3 mg / l, which meets the requirements of SanPiN 2.1.4.1074-01 "Drinking water".

Currently, there are several technologies used to purify water from iron. Aeration The injected oxygen oxidizes divalent iron, while removing carbon dioxide, which also accelerates the oxidation process. For this purpose, the following methods are used • * Gushing with spray installations; • Sprinkling-douching; • The discharge of air compressors. These methods are effectively used in the presence of iron up to 10 mg / dm3.in cases of exceeding the concentration to maintain the intensity of the process, preliminary water treatment is carried out by aeration with the introduction of reagents (chlorine, sodium hypochlorite, potassium permanganate). There are many ways to oxidize iron from 2+ to 3+, using lime or using chlorine (ClO2), ozone (O3), or using potassium permanganate (KMnO4). However, many years of experience with various de-Ironing systems shows that the most cost-effective, environmentally friendly and widely used method of iron oxidation is the de-Ironing method based on non-pressure aeration. Aeration provides the dissolved oxygen needed to convert iron into an insoluble form, without the use of chemical reagents. The essence of the method is that the processes of iron oxidation and collection of undissolved iron take place in separate modules. As a result, when organizing intensive mixing of water with air oxygen in the ejection system, complete oxidation of iron is achieved, and the collection of oxidized iron is carried out on sedimentary filters with an inert loading with a small specific weight and a developed surface. Air is a powerful oxidizer for both iron and hydrogen sulfide. It quickly converts 2+ to 3+ iron molecules, and reduces hydrogen sulfide to elemental sulfur, which is easily removed from water using a filter. Oxygen is a very strong and fast oxidizer, much faster than chlorine. Working for many years with various facilities where the task of removing iron from well water was set, the specialists developed and implemented an original technology for water purification from iron based on the method of non-pressure aeration. This water treatment from iron is especially actively used at industrial facilities, in the heat and utilities sector. Ozonation The method is based on the structure of the ozone molecule. The element is unstable and easily gives off an extra oxygen atom, which is an active oxidizer. Combining with molecules of other substances, it actively oxidizes and destroys them. Ozonation is the process of adding ozone to water to disinfect and improve some of its properties, such as color and smell. The Ozonation process leaves no chemicals in the water. Ozone has been used for water treatment since 1906 and is used all over the world.

Over time, ozone is gradually converted to oxygen. This depends on the temperature, pH, and water quality. The production and introduction of ozone into water must be consistent. The instability of Ozone is caused by a weak bond with the third oxygen atom and causes an oxidative reaction with any oxidizable substance.

Ozone is considered the most powerful oxidizing agent for water purification, which can be safely used as a strong disinfectant. Gallic organisms are considered the most resistant to all disinfectants because of their protective shells and effectively disappear, along with bacteria and viruses, when water is purified with ozone. In addition to iron, ozonation helps to clear the liquid of insoluble magnesium and calcium compounds that can be eliminated by mechanical filtration. It also disinfects, discolors, removes foreign odors and tastes. During ozonation, many bacteria die and toxic substances are removed. Ion exchange Water can be purified from iron by ion exchange resin. In recent years, natural components have been replaced with synthetic resins with high efficiency. The main task of ion exchange filtration is to get rid of other divalent metals: calcium and magnesium. In the laboratory, this method will remove a high concentration of metal, but on an industrial scale, the application of the method is difficult. The presence of oxygen in the liquid passing through the ion exchanger causes precipitation and rapid clogging of the sorbent. The process has to be suspended to wash the resin. Trivalent iron reduces the effective removal of calcium and manganese. The resin quickly becomes overgrown with an organic film. The ion exchange method is used when water purification is necessary. Chlorination Chlorine is an oxidizer that accelerates the process of converting an element from a divalent to a trivalent form. Chlorination solves the problem of disinfection, removal of hydrogen sulfide and manganese, organic substances. Liquid chlorine, a highly toxic, delivery and requires compliance with strict security measures. Oxidation with sodium hypochlorite Also, when water is purified from iron, Fe2+ to Fe3+ can be oxidized using sodium hypochlorite. This method has been adopted by water utilities, replacing the technology based on liquefied chlorine. The use of sodium hypochlorite for oxidation requires the installation of a dosing pump and a special device for entering the hypochlorite solution into the water stream. Water is supplied to the contact container for settling. Sometimes an additional coagulant can be added to the contact container to further facilitate the retention of impurities on the filter load. Then the water by means of pumps is fed to the pressure filters with granular load type: sand or anthracite in the mixture with sand download. This technology does not produce toxic effluents. Maintenance personnel are required to constantly monitor the operation of the pump, its regular flushing (often clogged as a result of crystallization of hypochlorite), as well as qualified handling of hypochlorite – this unstable substance decomposes quickly, its concentration decreases over time under the influence of many factors. In order to reduce operating costs when using sodium hypochlorite in water utilities, both for de-Ironing water, and for primary or secondary disinfection, it is recommended to install stations for the production of sodium hypochlorite from table salt by electrolysis. Benefits of sodium hypochlorite: The calculation of the dosing unit is based on data obtained during chemical laboratory analysis of the liquid composition. In addition to the iron content, the presence of heavy metals and hydrogen sulfide is taken into account. Catalytic oxidation The method is widely used for water supply of small businesses, cottages and private homes. Catalytic filtration units with compact dimensions can purify from 0.5 to 20 m3/h of liquid. Oxidation occurs in a special tank made of stainless steel or fiberglass. Synthetic materials with high efficiency and low cost are used for backfilling. Before being fed to the catalyst, the water is intensively aerated, which accelerates oxidation. The precipitate is removed by backwash. The disadvantage of synthetic backfill is the expense as a result of mechanical failure. There is no shortage of backfill made of dolomite, zeolite and glauconite. The materials are porous and resistant to high temperatures. Reverse osmosis
 * The solution of the substance does not form suspensions and does not need to settle.
 * The use of hypochlorite does not increase the water hardness, in comparison with solutions of bleach.
 * The chemical is obtained at the filtration site by electrolysis of table salt, a substance that is safe for transportation.
 * The drug has bactericidal properties – the process of cleaning from metal is combined with disinfection.

The systems use membranes whose openings allow only H20 molecules to pass through. Impurities of salts, heavy metals, microbes and bacteria are retained by 80-95%. But osmosis is not just a filter, where the entire volume of water passes through the filter element. In reverse osmosis, this process is not possible – the membranes are very quickly clogged with impurities. The design of reverse osmosis household appliances provides for the supply of liquid under pressure. The device filter divides the flow into 2 parts. A third of the liquid has time to seep out and get into a clean outlet, and about two-thirds of the water goes into the sewer. Thus, the filter membrane is polluted with less intensity and lasts from 2 to 4 years. The advantage of the system is the clean release of water from impurities. The disadvantages of reverse osmosis are the high cost of purchasing equipment and the periodic cost of replacing the membrane. In addition, most of the liquid goes to waste, which increases the cost of electricity for the pump. The coagulation and clarification Divalent iron in the form of suspensions and colloid-dispersed substances-is a liquid that acquires a whitish hue, which does not disappear after settling. They are released from suspensions by the introduction of reagents-coagulants. They adsorb metal on their surface and fall out as a precipitate, which is removed by filtration. Sulfates and chlorides are used as coagulants. Their choice depends on the acidity of the source liquid. Electrochemical purification method Electrochemical cleaning methods are simple technologically, do not involve the use of reagents. The disadvantage that reduces the prevalence of this method is the cost of electricity. The essence of the method is the passage of a liquid through the interelectrode space, where electrolysis, electrophoresis and removal of solutes occur. There are different types of electrochemical method: 1. Electrolysis. 2. Electroflotation. 3. Electrodialysis. 4. Electrocoagulation. The described methods are technologically difficult to implement with your own hands without the use of equipment manufactured by the industrial method. As an alternative to tap water, we are used to accepting purchased water - either in bottles or on tap. The manufacturer filters it, so this water is more softened. This can be easily checked by the condition of the kettle in which the water is boiling. With regular use of tap water, it forms a plaque-the deposition of the very salts that distinguish one water from another. Soft water from the store usually leaves the kettle clean. However, the question of the undoubted advantages of purchased water is not as simple as it seems at first glance. First, along with excess chemical elements from such water, substances necessary for the normal functioning of the human body can also be filtered out. Secondly, the consumer cannot know exactly what kind of cleaning the manufacturer performs in this particular case. Third, the very process of spreading such water is fraught with possible difficulties. Manufacturers of bottled water enter into a production control agreement with the center for hygiene and epidemiology or other certified laboratory. They are obliged to do this by sanitary rules. A schedule of water studies is drawn up, according to which it is checked for quality. Samples are sent to doctors in a "depersonalized", numbered form. The research result is also encoded. The Protocol is written after matching the code with the selection report. This is done to maximize the objectivity of the data obtained. If non-compliance with the standards is detected, information is provided only to the manufacturer. Then the comments are removed and the water is re-examined. Experts believe that such a control system is effective: it is profitable for the manufacturer to eliminate comments (if they appear) and continue working calmly. Specially built independent control by the state is not required here. Another common misconception – if you drink a lot of therapeutic mineral water, it will strengthen your health. In fact, such water, like any medicine, should be used only on a limited basis, preferably on the recommendation of a specialist. Otherwise, you can achieve the exact opposite of the desired result. Mineral water contains a large number of different salts, trace elements and biologically active components. It rarely happens canteen, so it is almost never recommended in large quantities. As a rule, these are medicinal waters. Excesses of this kind will be harmful. Regarding springs and wells, it should be remembered that the water in them does not come from artesian sources. It is much closer to the surface of the earth. In this regard, water sources of this type are the least protected from possible contamination. A spring is precipitation that has passed through the filter of the earth's thickness. As a sanitary doctor, the chief doctor Of the center for hygiene and epidemiology of the Belgorod region, Alexander Krasnoperov, participated in the selection of water from springs, wells, and captages. Very often there is a discrepancy in microbiological indicators. The water is clear, cold, and delicious, but the Microbiology is inconsistent. Although this does not mean that it is dangerous in sexual relations. Pathogens of intestinal infections may not be there. Therefore, epidemiologists strongly recommend drinking water only from proven sources. If you find an undeveloped spring, the water in which looks great on the outside, is pleasant to the taste-this does not say anything about its possible "population". Such water can contain both microorganisms and harmful "chemistry", information about which can only be obtained in specialized laboratories. If the spring is equipped by the authorities, it means that they are responsible for it. The water in it is researched and safe for consumers. Unfortunately, the question of what water is best for a particular person to drink is not easy to simplify. If you drink softened water, the body may lose the necessary minerals. This is not always useful. Tap water, on the other hand, can deliver unnecessary chemical compounds to the internal organs. Or deliver the necessary ones, but in more than the required quantity. The most correct way to understand this complex issue is to get direct recommendations from doctors. For example, if you are at risk of developing urolithiasis due to metabolic disorders, it is better to limit the intake of tap water. If there are no contraindications, it is advisable to drink water in combination. But only a doctor can give you the right advice based on the results of analytical studies of your body.