Methods of water treatment in municipal services include: Water treatment project, water treatment technology

Living in a huge metropolis with a not very good environment, people try to expose their health to as little risk as possible. Much attention is paid to water these days. It is the main product of consumption in the life of every person, so issues of hardness and purification come first. Thanks to water treatment technologies, it is possible to obtain significantly purified water that is suitable for consumption. Experts in this industry are constantly struggling with the problem of water hardness to ensure that people only drink clean water.

Why does the issue of water hardness worry experts so much nowadays? Many of us have seen scale on a kettle or other utensils. Also, increased water hardness will leave harmful consequences. Few people paid much attention to this and analyzed this problem. Why does scale form, and why is it so scary?

Many signs will help you determine what type of water you are using. It is scale and poor heat conductivity that are the main signs of hard water. Many housewives are accustomed to removing scale and not paying much attention to it. But you need to understand how much harm such water brings to your health and you should not lose sight of it.

The most important thing to remember is that hard water contaminates not only the pipes through which it flows, but also all harmful elements settle on the walls of our body. This is what leads to many diseases. Also, an incorrect lifestyle and poor water quality cause great harm to your health and cause many chronic diseases.

Water hardness also increases water consumption during washing. We may not notice this, since we are accustomed to consuming exactly this amount of water from year to year. If we consider why the volume of water used is the way it is, everything will become clear. Since hard water does not dissolve detergent well, we have to add much more water; after washing, we also need more water for rinsing, since the salts that have settled in our clothes will be very difficult to wash out the first time.

The use of water treatment for a hot water boiler will show the difference between the amount of water consumed “before” and “after”.

Nowadays, people think that a water filter is an unaffordable luxury and their use is not so important. Re-read the first paragraphs and think again. Are things spoiled by white stains, constant scale on dishes and, most importantly, spoiled health really more necessary? With water treatment technology, you will forever forget about these problems and feel the huge difference between hard water and soft water.

Scale also has a major disadvantage in the form of poor thermal conductivity. If you don’t remove scale from your appliances in time, you may simply be left without it.

When scale reaches the heating elements and covers them, heat transfer almost completely stops. At the beginning, limescale still allows a little heat to pass through, but fuel or electricity consumption increases significantly. It becomes more and more difficult to heat such a surface. The growth of fuel or electricity increases along with the scale layer
Fuel consumption is not the main problem. After a large layer of scale has accumulated on the device, it will begin to turn off, thereby trying to protect itself from overheating. These are the main signals that indicate the imminent combustion of the device; you need to respond immediately. Cleaning such a device must be done immediately. If you do not clean the scale in time, it will turn into limestone, which is much more difficult to clean. There is also a risk of losing the device. If you do not clean the device even after the formation of limestone, then the heat will have nowhere to escape, and it will tear the device. To avoid all these troubles, you need to study water treatment technologies.

In everyday life, this can result in overheating of the device and even burnt wiring. In industry, this results in fistulas in pipes and explosions of boilers in thermal power engineering.

This is just a small part of the reasons that will make you think about installing water treatment for boiler systems. Make your family's life more comfortable. Let your appliances serve you longer, and you won’t have to clean off scale, and your things will no longer have white salt stains. When choosing a specific water treatment technology, you should remember that a water softener alone is not enough. It’s better to save on everything else, but not on your health.

Water treatment technology

We should not forget that when purifying water, you face two tasks. You need water for food consumption, i.e. drinking and for domestic needs. Based on this, the minimum water treatment process would be water purification using, for example, an electromagnetic emitter. Water that has passed this stage of purification is perfect for domestic needs. For drinking water, minimal measures are used for filter purification, and the highest quality is reverse osmosis purification. In this case, protection against scale and hard water will be most effective.

Where and how can I find out the initial data in order to correctly determine the required type of water treatment and the sequence of arrangement of filter elements?

The first step is to conduct a chemical analysis of the water. Only on its basis will it be possible in the future to calculate the necessary data, the volume of water, all additives and impurities. Having received the results of such a study, it is quite easy to decide on the cleaning method, understand the technology itself, and draw up a plan for the placement of water filters, as well as calculate their power.

Even if you use water from a central purification system, it will be hard. Therefore, you should not save on your own health and conduct a special analysis. This may help you save money, because when calculating, it may turn out that a filter with a power less than what you wanted to take is enough, which will provide a good saving option.

Water treatment technologies can be broadly divided into the following types:

• · mechanical water purification;
• · chemical water purification;
• · disinfection;
• · micro-cleaning.

Chemical cleaning involves the complete removal of various impurities and nitrates, iron and chlorine.

Microcleaning ultimately provides a finished product called distillate, or absolutely pure water.

We should dwell in more detail on water filters, which in turn operate under one of the current purification technologies.

Mechanical technology. Its task is to remove all organic heavy impurities from the water composition. It can take place in several stages. The first is rough cleaning. It is also possible to use sedimentation, with the participation of sediment and gravel mesh filters in the process.

Mesh filters involve several meshes with different throughputs. They are used to filter solids of all sizes. These meshes are mainly made from stainless steel. Such filters are installed during the first water intake, at the initial stage.

Sedimentation removes smaller impurities, those that cannot be seen with the naked eye. The main filtration material is quartz sand. This type of filter is used for repeated cleaning. In this way, wastewater is purified, or water is prepared at production sites.

Cartridges. Filters of this component are something in between the previous two options. It is also used for repeated purification using reverse osmosis. The advantage is the ability to remove particles measuring 150-1 microns.

Chemical cleaning. It is a rather interesting and more promising technology than its predecessors. Purification involves adjusting the chemical composition of water without changing its condition. Purification is carried out in an off-line mode, while water softening, iron removal and chlorine removal are carried out through ion exchange.

Manganese cyanide is used separately for iron removal. It is greenish sand; it comes into maximum contact with ferrous compounds and removes them from the water. The addition of silicon also helps speed up the process and improve cleaning.

Another option is to oxidize iron with water to clean it of impurities. This process is reagent-free, and special filters are additionally used in which the water is blown with oxygen, due to which the iron settles on the internal cartridge.

Ion exchange devices are used to soften water. Such filters are among the most common, both in everyday life and in production. At the base of the filter is a resin cartridge, which in turn is supersaturated with sodium, making its atoms easy to replace. Thus, when it comes into contact with water, the light sodium atoms are replaced by heavy metal elements and by-products. Over time, the cartridge is completely filled with liquid salts and stops the ionization process.

If we consider an industrial water treatment system, it should be noted that ionizing units are the most popular, and also one of the most bulky, since they are large, high tanks. But, despite this, a huge advantage is the highest cleaning speed compared to other systems.

As for the cartridges of such installations, in everyday life they are replaced with new ones, and at production facilities they are restored and reused. Since the ion exchange filter is considered a reagent softener, it could not be used for purifying water for food consumption until the invention of replaceable cartridges.

Restoration of cartridges is carried out using a highly salty solution. For home use, it is simply replaced, which makes using such a system quite expensive. The installation itself is not very expensive, but the constant change of the cleaning reagent creates a constant need for expense. However, you have to change it quite often. In a production environment, quite large expenses are incurred on the purchase of salt. The material is not expensive, but you need quite a lot of it, and you have to buy it constantly. Also, after restoration, the cartridge emits harmful waste, which is strictly prohibited from being released into the atmosphere without special permission and additional treatment. Cleaning it also requires additional financial costs. However, compared to the cost of reverse osmosis, these production costs are considered insignificant.

New and modern water treatment technologies

For household needs, in order to save money, you can purchase a so-called filter jug. But in truth, the purchase and installation of reverse osmosis will pay off many times faster than a similar purchase, again taking into account the constant costs of changing the filter.

To remove residual chlorine and cloudy color from water, activated carbon is usually used, which is the basis of the sorbed filter.

To perform disinfection, ozonizers or ultraviolet water filters are used. The main task of modern filters is to completely purify water from various bacteria and viruses. In most cases, ozonizers are used to clean the pool, although they are quite expensive, they are environmentally friendly. Ultraviolet filters are a reagent-free installation; cleaning is carried out by irradiating water with ultraviolet light, under the influence of which all bacteria and viruses die.

Another quite popular cleaning option today is electromagnetic water softening. These technologies are mainly used in thermal power engineering. But such installations were also popularized in everyday life. The main parts of such a device are permanent magnets and an electrical processor. Cleaning takes place by exposing hardness salts to magnetic waves, under the influence of which they are modified.

Further, having acquired a modified form, they are not able to stick to the surface. And their thin rough surface can only rub against old scale, which gives a positive effect, since the destroyed new salts eliminate the old ones by their friction. At the same time, the process is performed quite efficiently.

If you install an electromagnetic water softener, after a month, try removing the boiler and see the effect. Be sure you will be satisfied with the result. And taking into account the fact that the device does not require maintenance, it can be easily removed and installed by yourself, and does not require washing or replacing components. The only condition for use is that it must be installed on a clean piece of pipe, so you may have to change a small piece.

And the last method, which is the latest and at the peak of technology, is nanofiltration and reverse osmosis, which results in a distillate at the output. These technologies involve fine water purification. In the process, water is purified at the molecular level, passing through a dispersion membrane with a huge number of holes no larger than a water molecule. The only disadvantage is the mandatory preliminary preparation of water. Only after purification of a lower level can purification by osmosis be carried out. Due to such factors, these installations are the most expensive, and the materials for replacing the membrane are also not cheap. But at the same time, the quality of cleaning is the highest of all.

Thus, it should be noted that all types and methods of water treatment have been discussed, thanks to which, now, you are fully aware of how each type of purification device works. Guided by this information, it will be quite easy to assemble the necessary water treatment system for your home or production.

If we do not respond to you within 2 hours, we guarantee you a 10% discount on the full cost of the work. To do this, we ask you to write to, indicating in the subject line WATER TREATMENT TECHNOLOGY a 10% discount.

This section describes in detail the existing traditional methods of water treatment, their advantages and disadvantages, and also presents modern new methods and new technologies for improving water quality in accordance with consumer requirements.

The main objectives of water treatment are to obtain clean, safe water suitable for various needs: household, drinking, technical and industrial water supply taking into account the economic feasibility of using the necessary methods of water purification and water treatment. The approach to water treatment cannot be the same everywhere. The differences are due to the composition of the water and the requirements for its quality, which vary significantly depending on the purpose of the water (drinking, industrial, etc.). However, there is a set of typical procedures used in water treatment systems and the sequence in which these procedures are used.

Basic (traditional) methods of water treatment.

In water supply practice, in the process of purification and treatment, water is subjected to lightening(removal of suspended particles), discoloration ( removal of substances that give color to water) , disinfection(destruction of pathogenic bacteria in it). Moreover, depending on the quality of the source water, in some cases special methods of improving water quality are additionally used: softening water (reduction of hardness due to the presence of calcium and magnesium salts); phosphating(for deeper water softening); desalination, desalting water (reducing the overall mineralization of water); desiliconization, deferrization water (release of water from soluble iron compounds); degassing water (removal of soluble gases from water: hydrogen sulfide H 2 S, CO 2, O 2); deactivation water (removal of radioactive substances from water); neutralization water (removal of toxic substances from water), fluoridation(adding fluoride to water) or defluoridation(removal of fluorine compounds); acidification or alkalization ( to stabilize water). Sometimes it is necessary to eliminate tastes and odors, prevent the corrosive effects of water, etc. Certain combinations of these processes are used depending on the category of consumers and the quality of water in the sources.

The quality of water in a water body and is determined by a number of indicators (physical, chemical and sanitary-bacteriological), in accordance with the purpose of the water and established quality standards. More about this in the next section. By comparing water quality data (obtained from analysis) with consumer requirements, measures for its treatment are determined.

The problem of water purification covers issues of physical, chemical and biological changes during the treatment process in order to make it suitable for drinking, i.e., purifying and improving its natural properties.

The method of water treatment, the composition and design parameters of treatment facilities for technical water supply and the calculated doses of reagents are established depending on the degree of pollution of the water body, the purpose of the water supply system, the productivity of the station and local conditions, as well as on the basis of data from technological research and operation of structures operating in similar conditions .

Water purification is carried out in several stages. Debris and sand are removed at the pre-cleaning stage. A combination of primary and secondary treatment carried out at water treatment plants (WTPs) removes colloidal material (organic matter). Dissolved nutrients are eliminated using post-treatment. For treatment to be complete, water treatment plants must eliminate all categories of contaminants. There are many ways to do this.

With appropriate post-treatment and high-quality WTP equipment, it is possible to achieve the end result of water suitable for drinking. Many people turn pale at the thought of recycling sewage, but it is worth remembering that in nature, in any case, all water cycles. In fact, appropriate post-treatment can provide water of better quality than that obtained from rivers and lakes, which often receive untreated sewage.

Basic methods of water treatment

Water clarification

Clarification is a stage of water purification, during which the turbidity of water is eliminated by reducing the content of suspended mechanical impurities in natural and waste water. The turbidity of natural water, especially surface sources during the flood period, can reach 2000-2500 mg/l (at the norm for drinking water - no more than 1500 mg/l).

Water clarification by sedimentation of suspended substances. This function is performed clarifiers, sedimentation tanks and filters, which are the most common water treatment plants. One of the most widely used practical methods for reducing the content of finely dispersed impurities in water is their coagulation(precipitation in the form of special complexes - coagulants) followed by sedimentation and filtration. After clarification, the water enters clean water tanks.

Discoloration of water, those. elimination or decolorization of various colored colloids or completely dissolved substances can be achieved by coagulation, the use of various oxidizing agents (chlorine and its derivatives, ozone, potassium permanganate) and sorbents (activated carbon, artificial resins).

Clarification by filtration with preliminary coagulation helps to significantly reduce bacterial contamination of water. However, among the microorganisms remaining in the water after water treatment there may also be pathogenic ones (typhoid fever bacilli, tuberculosis and dysentery; cholera vibrio; polio and encephalitis viruses), which are a source of infectious diseases. For their final destruction, water intended for domestic purposes must be subjected to mandatory disinfection.

Disadvantages of coagulation, settling and filtration: costly and ineffective water treatment methods, which requires additional quality improvement methods.)

Water disinfection

Disinfection or disinfection is the final stage of the water treatment process. The goal is to suppress the vital activity of pathogenic microbes contained in the water. Since neither settling nor filtering provides complete release, chlorination and other methods described below are used to disinfect water.

In water treatment technology, a number of water disinfection methods are known, which can be classified into five main groups: thermal; sorption on active carbon; chemical(using strong oxidizing agents); oligodynamy(exposure to noble metal ions); physical(using ultrasound, radioactive radiation, ultraviolet rays). Of the listed methods, the methods of the third group are the most widely used. Chlorine, chlorine dioxide, ozone, iodine, and potassium permanganate are used as oxidizing agents; hydrogen peroxide, sodium and calcium hypochlorite. In turn, of the listed oxidizing agents, in practice preference is given to chlorine, bleach, sodium hypochloride. The choice of water disinfection method is made based on the flow rate and quality of the water being treated, the efficiency of its pre-treatment, the conditions of supply, transport and storage of reagents, the possibility of automating processes and mechanizing labor-intensive work.

Water that has undergone previous stages of treatment, coagulation, clarification and discoloration in a layer of suspended sediment or settling, filtering is subject to disinfection, since the filtrate does not contain particles on the surface or inside of which bacteria and viruses can be in an adsorbed state, remaining outside the influence of disinfecting agents.

Disinfection of water with strong oxidizing agents.

Currently, at housing and communal services facilities, water disinfection is usually chlorination water. If you drink tap water, you should know that it contains organochlorine compounds, the amount of which after the water disinfection procedure with chlorine reaches 300 μg/l. Moreover, this amount does not depend on the initial level of water pollution; these 300 substances are formed in water due to chlorination. Consumption of such drinking water can seriously affect your health. The fact is that when organic substances combine with chlorine, trihalomethanes are formed. These methane derivatives have a pronounced carcinogenic effect, which promotes the formation of cancer cells. When chlorinated water is boiled, it produces a powerful poison - dioxin. The content of trihalomethanes in water can be reduced by reducing the amount of chlorine used or replacing it with other disinfectants, for example, using granular activated carbon to remove organic compounds formed during water purification. And, of course, we need more detailed control over the quality of drinking water.

In cases of high turbidity and color of natural waters, preliminary chlorination of water is commonly used, but this method of disinfection, as described above, is not only not effective enough, but also simply harmful to our body.

Disadvantages of chlorination: is not effective enough and at the same time causes irreversible harm to health, since the formation of the carcinogen trihalomethanes promotes the formation of cancer cells, and dioxin leads to severe poisoning of the body.

It is not economically feasible to disinfect water without chlorine, since alternative methods of water disinfection (for example, disinfection with ultraviolet radiation) are quite expensive. An alternative method to chlorination was proposed for water disinfection using ozone.

Ozonation

A more modern procedure for water disinfection is water purification using ozone. Really, ozonation At first glance, water is safer than chlorination, but it also has its drawbacks. Ozone is very unstable and is quickly destroyed, so its bactericidal effect is short-lived. But the water must still pass through the plumbing system before ending up in our apartment. A lot of trouble awaits her along this path. It is no secret that water supply systems in Russian cities are extremely worn out.

In addition, ozone also reacts with many substances in water, such as phenol, and the resulting products are even more toxic than chlorophenols. Ozonation of water turns out to be extremely dangerous in cases where bromine ions are present in the water, even in the most insignificant quantities, difficult to determine even in laboratory conditions. Ozonation produces toxic bromine compounds - bromides, which are dangerous to humans even in microdoses.

The water ozonation method has proven itself very well for treating large masses of water - in swimming pools, in communal systems, i.e. where more thorough water disinfection is needed. But it must be remembered that ozone, as well as the products of its interaction with organochlorines, is poisonous, therefore the presence of large concentrations of organochlorines at the water treatment stage can be extremely harmful and dangerous for the body.

Disadvantages of ozonation: The bactericidal effect is short-lived, and in reaction with phenol it is even more toxic than chlorophenols, which is more dangerous for the body than chlorination.

Disinfection of water with bactericidal rays.

CONCLUSIONS

All of the above methods are not effective enough, are not always safe, and, moreover, are not economically feasible: firstly, they are expensive and very costly, requiring constant maintenance and repair costs, secondly, they have a limited service life, and thirdly, they consume a lot of energy resources. .

New technologies and innovative methods for improving water quality

The introduction of new technologies and innovative methods of water treatment makes it possible to solve a set of problems that ensure:

• production of drinking water that meets established standards and GOSTs and meets consumer requirements;
• reliability of water purification and disinfection;
• effective uninterrupted and reliable operation of water treatment facilities;
• reducing the cost of water purification and water treatment;
• saving reagents, electricity and water for your own needs;
• quality of water production.

New technologies for improving water quality include:

Membrane methods based on modern technologies (including macrofiltration; microfiltration; ultrafiltration; nanofiltration; reverse osmosis). Used for desalination Wastewater, solve a complex of water purification problems, but purified water does not mean that it is healthy. Moreover, these methods are expensive and energy-intensive, requiring constant maintenance costs.

Reagent-free water treatment methods. Activation (structuring)liquids. Today there are many known ways to activate water (for example, magnetic and electromagnetic waves; ultrasonic frequency waves; cavitation; exposure to various minerals, resonance, etc.). The liquid structuring method provides a solution to a set of water treatment problems ( decolorization, softening, disinfection, degassing, deferrization of water etc.), while eliminating chemical water treatment.

Water quality indicators depend on the liquid structuring methods used and depend on the choice of technologies used, among which are:
- magnetic water treatment devices;
- electromagnetic methods;
- cavitation method of water treatment;
- resonant wave water activation (non-contact processing based on piezocrystals).

Hydromagnetic systems (HMS) designed for treating water in a flow with a constant magnetic field of a special spatial configuration (used to neutralize scale in heat exchange equipment; to clarify water, for example, after chlorination). The operating principle of the system is the magnetic interaction of metal ions present in water (magnetic resonance) and the simultaneous process of chemical crystallization. HMS is based on the cyclic effect on water supplied to heat exchangers by a magnetic field of a given configuration created by high-energy magnets. The magnetic water treatment method does not require any chemical reagents and is therefore environmentally friendly. But there are also disadvantages. HMS uses powerful permanent magnets based on rare earth elements. They retain their properties (magnetic field strength) for a very long time (tens of years). However, if they are overheated above 110 - 120 C, the magnetic properties may weaken. Therefore, HMS must be installed where the water temperature does not exceed these values. That is, before it heats up, on the return line.

Disadvantages of magnetic systems: the use of HMS is possible at temperatures no higher than 110 - 120°WITH; insufficiently effective method; For complete cleaning it is necessary to use it in combination with other methods, which ultimately is not economically feasible.

Cavitation method of water treatment. Cavitation is the formation of cavities in a liquid (cavitation bubbles or cavities) filled with gas, steam or a mixture thereof. The essence cavitation- another phase state of water. Under conditions of cavitation, water changes from its natural state to steam. Cavitation occurs as a result of a local decrease in pressure in the liquid, which can occur either with an increase in its speed (hydrodynamic cavitation) or with the passage of an acoustic wave during the rarefaction half-cycle (acoustic cavitation). In addition, the sharp (sudden) disappearance of cavitation bubbles leads to the formation of hydraulic shocks and, as a consequence, to the creation of a compression and tension wave in the liquid at an ultrasonic frequency. The method is used to remove iron, hardness salts and other elements exceeding the maximum permissible concentration, but is poorly effective in disinfecting water. At the same time, it consumes significant energy and is expensive to maintain with consumable filter elements (resource from 500 to 6000 m 3 of water).

Disadvantages: consumes electricity, is not efficient enough and is expensive to maintain.

CONCLUSIONS

The above methods are the most effective and environmentally friendly compared to traditional methods of water purification and water treatment. But they have certain disadvantages: the complexity of the installations, high cost, the need for consumables, difficulties in maintenance, significant areas are required to install water treatment systems; insufficient efficiency, and in addition restrictions on use (restrictions on temperature, hardness, pH of water, etc.).

Methods of non-contact activation of liquid (NL). Resonance technologies.

Liquid processing is carried out contactlessly. One of the advantages of these methods is the structuring (or activation) of liquid media, which provides all of the above tasks by activating the natural properties of water without consuming electricity.

The most effective technology in this area is NORMAQUA Technology ( resonant wave processing based on piezocrystals), contactless, environmentally friendly, no electricity consumption, non-magnetic, maintenance-free, service life - at least 25 years. The technology is based on piezoceramic activators of liquid and gaseous media, which are inverter resonators emitting ultra-low intensity waves. As with the influence of electromagnetic and ultrasonic waves, under the influence of resonant vibrations, unstable intermolecular bonds are broken, and water molecules are arranged in a natural physical and chemical structure in clusters.

The use of technology makes it possible to completely abandon chemical water treatment and expensive water treatment systems and consumables, and achieve the ideal balance between maintaining the highest water quality and saving equipment operating costs.

Reduce water acidity (increase pH level);
- save up to 30% of electricity on transfer pumps and erode previously formed scale deposits by reducing the friction coefficient of water (increasing the capillary suction time);
- change the redox potential of water Eh;
- reduce overall rigidity;
- improve the quality of water: its biological activity, safety (disinfection up to 100%) and organoleptic properties.

In the conditions of a modern big city, with polluted air and a rather poor environment, every person strives to maintain health. Water is the main product for each of us. Recently, more and more people are thinking about what kind of water they use. In this regard, water hardness and water purification are not empty terms, but important parameters. Today, specialists successfully use water treatment and water purification technologies, which helps obtain much cleaner water suitable for consumption. Professionals also pay attention to water softening, carrying out a number of measures to improve its properties.

What do water treatment technologies provide?

Let's take a closer look at what water treatment technologies are. This is primarily the purification of water from plankton. This microorganism, which lives in rivers, began to develop most intensively after large reservoirs appeared. Note that when plankton develops in large quantities, the water begins to smell unpleasant, change color and acquire a characteristic taste.

Today, many industrial companies pour their untreated wastewater into rivers with a huge content of organic pollutants and chemical impurities. Drinking water is subsequently obtained from these open reservoirs. As a result, most of them, mainly those located in or near megacities, are very polluted. The water contains phenols, organochlorine pesticides, ammonium and nitrite nitrogen, petroleum products and other harmful substances. Of course, water from such sources is unsuitable for consumption without prior preparation.

We should not forget about new production technologies, various emergencies and accidents. All these factors can also worsen the condition of water in sources and negatively affect its quality. Thanks to modern research methods, scientists were able to find oil products, amines, phenols, and manganese in water.

Water treatment technologies, when it comes to a city, include the construction of water treatment plants. By passing through several stages of purification, water becomes more suitable for drinking. But nevertheless, even with the use of water treatment facilities, it is not completely freed from harmful impurities, and therefore it enters our homes still quite contaminated.

Today, there are various technologies for water treatment and purification of drinking and waste water. As part of these measures, mechanical purification is used to remove various impurities using installed filters, remove residual chlorine and chlorine-containing elements, purify water from a large amount of mineral salts contained in it, and also soften and remove salts and iron.

Basic water treatment and water purification technologies

Technology 1. Lightening

Clarification is the stage of water purification at which its turbidity is eliminated, reducing the amount of mechanical impurities in natural and waste waters. The level of turbidity in water, especially in surface sources during floods, sometimes reaches 2000-2500 mg/l, while the norm for water suitable for drinking and household use is no more than 1500 mg/l.

Water is clarified by precipitating suspended substances using special clarifiers, settling tanks and filters, which are the most well-known water treatment facilities. One of the most well-known methods widely used in practice is coagulation, that is, reducing the amount of finely dispersed impurities in water. As part of this water treatment technology, coagulants are used - complexes for sedimentation and filtration of suspended substances. Next, the clarified liquid enters clean water tanks.

Technology 2. Discoloration

Coagulation, the use of various oxidizing agents (for example, chlorine along with its derivatives, ozone, manganese) and sorbents (active carbon, artificial resins) make it possible to decolorize water, that is, eliminate or discolor colored colloids or completely dissolved substances in it.

Thanks to this water treatment technology, water contamination can be significantly reduced by eliminating most bacteria. Moreover, even after removing some harmful substances, others often remain in the water, for example, bacilli of tuberculosis, typhoid fever, dysentery, Vibrio cholera, encephalitis and polio viruses that cause infectious diseases. In order to completely destroy them, water used for domestic and economic needs must be disinfected.

Coagulation, sedimentation and filtration have their disadvantages. These water treatment technologies are insufficiently efficient and expensive, and therefore it is necessary to use other methods of purification and improvement of water quality.

Technology 3. Desalting

With this water treatment technology, all anions and cations that affect the salt content in general and the level of its electrical conductivity are removed from water. When desalting, reverse osmosis, ion exchange and electrodeionization are used. Depending on the level of salt content and what requirements exist for demineralized water, the appropriate method is chosen.

Technology 4. Disinfection

The final stage of water purification is disinfection, or disinfection. The main task of this water treatment technology is to suppress the activity of harmful bacteria in the water. To completely purify water from microbes, filtration and sedimentation are not used. To disinfect it, it is chlorinated, and other water treatment technologies are used, which we will discuss later.

Today, experts use many methods of water disinfection. Water treatment technologies can be divided into five main groups. The first method is thermal. The second is sorption on active carbon. The third is chemical, in which strong oxidizing agents are used. The fourth is oligodynamy, in which ions act on noble metals. The fifth is physical. This water treatment technology uses radioactive radiation, ultraviolet rays and ultrasound.

As a rule, when disinfecting water, chemical methods are used using ozone, chlorine, chlorine dioxide, potassium permanganate, hydrogen peroxide, sodium hypochlorite and calcium as oxidizing agents. As for a specific oxidizing agent, in this case chlorine, sodium hypochloride, and bleach are most often used. The disinfection method is chosen based on the consumption and quality of the water being treated, the effectiveness of its initial purification, the conditions for transportation and storage of reagents, the ability to automate processes and mechanize complex work.

Specialists disinfect water that has been pre-treated, coagulated, clarified and discolored in a layer of suspended sediment, or settled, filtered, since the filter does not contain particles on or inside of which adsorbed microbes that have not been disinfected can be located.

Technology 5.Disinfection using strong oxidizing agents

At the moment, in the housing and communal services sector, water is usually chlorinated in order to purify and disinfect it. When drinking tap water, you should be aware of the content of organochlorine compounds, the level of which after disinfection using chlorine is up to 300 μg/l. At the same time, the initial threshold of contamination does not affect this indicator, since it is chlorination that causes the formation of these 300 microelements. It is highly undesirable to consume water with such indicators. Chlorine, combining with organic substances, forms trihalomethanes - methane derivatives, which have a pronounced carcinogenic effect, as a result of which cancer cells appear.

When chlorinated water is boiled, it produces a highly toxic substance called dioxin. You can reduce the level of trihalomenates in water by reducing the amount of chlorine used during disinfection and replacing it with other disinfection substances. In some cases, granular activated carbon is used to remove organic compounds formed during disinfection. Of course, we should not forget about complete and regular monitoring of drinking water quality indicators.

If natural waters are very cloudy and have a high color, they often resort to preliminary chlorination. But, as mentioned earlier, this water treatment technology does not have sufficient efficiency, and it is also very harmful to our health.

The disadvantages of chlorination as a water treatment technology, therefore, include low efficiency plus enormous damage to the body. When the carcinogen trihalomethane is formed, cancer cells appear. Regarding the formation of dioxin, this element, as noted above, is a powerful poison.

Without the use of chlorine, water disinfection is not feasible from an economic point of view. Various alternative water treatment technologies (for example, disinfection using UV radiation) are quite expensive. The best option today is water disinfection using ozone.

Technology 6.Ozonation

Disinfection using ozone seems safer than chlorination. But this water treatment technology also has its disadvantages. Ozone does not have increased resistance and is prone to rapid destruction, and therefore has a bactericidal effect for a very short time. This requires water to pass through the plumbing system before entering our homes. This is where difficulties arise, since we all have an idea of ​​the approximate degree of deterioration of water pipes.

Another nuance of this water treatment technology is that ozone reacts with many substances, including, for example, phenol. The elements formed during their interaction are even more toxic. Disinfecting water using ozone is a dangerous undertaking if the water contains a tiny percentage of bromine ions (it is difficult to detect even in the laboratory). When ozonation is performed, toxic bromine compounds appear - bromides, which pose a danger to humans even in microdoses.

In this case, ozonation is the best option for disinfecting large volumes of water, requiring thorough disinfection. But do not forget that ozone, like the substances that appear during its reactions with organochlorines, is a toxic element. In this regard, a high concentration of organochlorines at the stage of water purification can pose great harm and a health hazard.

So, the disadvantages of disinfection using ozone include even greater toxicity when interacting with phenol, which is even more dangerous than chlorination, as well as a short bactericidal effect.

Technology 7.Disinfection using bactericidal rays

To disinfect groundwater, bactericidal rays are often used. They can be used only if the coli index of the initial state of the water is not higher than 1000 units/l, the iron content is up to 0.3 mg/l, and the turbidity is up to 2 mg/l. Compared to disinfection with chlorine, the bactericidal effect on water is optimal. There are no changes in the taste of water and its chemical properties when using this water treatment technology. The rays penetrate the water almost instantly, and after their exposure it becomes suitable for consumption. Using this method, not only vegetative but also spore-forming bacteria are destroyed. In addition, using installations for water disinfection in this way is much more convenient than using chlorination.

In the case of untreated, turbid, colored or waters in which the level of iron content is high, the absorption coefficient turns out to be so strong that the use of bactericidal rays becomes unjustified from an economic point of view and not sufficiently reliable from a sanitary point of view. In this regard, the bactericidal method is better used to disinfect already purified water or to disinfect groundwater that does not require purification, but requires disinfection for prevention.

The disadvantages of disinfection using bactericidal rays include the economic unjustification and unreliability of this water treatment technology from a sanitation point of view.

Technology 8.Deferrization

The main sources of iron compounds in natural water are weathering processes, soil erosion and rock dissolution. As for drinking water, iron may be present in it due to corrosion of water supply pipes, and also because municipal treatment plants used iron-containing coagulants to clarify the water.

There is a modern trend in non-chemical methods of groundwater purification. This is a biological method. This water treatment technology is based on the use of microorganisms, most often iron bacteria, which convert Fe 2 + (ferrous iron) into Fe 3 + (rust). These elements are not hazardous to human health, but their waste products are quite toxic.

The basis of modern biotechnologies is the use of the properties of a catalytic film, which is formed on a load of sand and gravel or other similar material with small pores, as well as the ability of iron bacteria to ensure the occurrence of complex chemical reactions without energy costs and reagents. These processes are natural, and they are based on biological natural laws. Iron bacteria actively and in large numbers develop in water, the iron content of which is from 10 to 30 mg/l, but practice shows that they can live at a lower concentration (100 times). The only condition here is to maintain a sufficiently low level of acidity of the environment and the simultaneous access of oxygen from the air, at least in a small volume.

The final stage of application of this water treatment technology is sorption purification. It is used to retain bacterial waste products and carry out final disinfection of water using bactericidal rays.

This method has quite a few advantages, the most important of which is, for example, environmental friendliness. He has every chance for further development. However, this water treatment technology also has a disadvantage - the process takes a lot of time. This means that in order to ensure large production volumes, tank structures must be large-sized.

Technology 9. Dgassing

The corrosive aggressiveness of water is influenced by certain physical and chemical factors. In particular, water becomes aggressive if it contains dissolved gases. As for the most common and corrosive elements, carbon dioxide and oxygen can be noted here. It is no secret that if the water contains free carbon dioxide, oxygen corrosion of the metal becomes three times more intense. In this regard, water treatment technologies always involve the removal of dissolved gases from water.

There are main ways to remove dissolved gases. Within their framework, physical desorption is used, and they also use chemical methods of binding them to remove residual gas. The use of such water treatment technologies, as a rule, requires high energy costs, large production areas, and consumption of reagents. In addition, all this can cause secondary microbiological contamination of water.

All of the above circumstances contributed to the emergence of a fundamentally new water treatment technology. This is membrane degassing, or degasification. Using this method, specialists, using a special porous membrane into which gases can penetrate, but water cannot penetrate, remove gases dissolved in water.

The basis of the action of membrane degassing is the use of special large-area membranes (usually created on the basis of hollow fiber) placed in pressure housings. Gas exchange processes occur in their micropores. Membrane water treatment technology makes it possible to use more compact installations, and the risks that water will again be subject to biological and mechanical contamination are minimized.

Thanks to membrane degassers (or MDs), it is possible to remove dissolved gases from water without dispersing it. The process itself is carried out in water, then in a membrane, then in a gas flow. Despite the presence of an ultraporous membrane in MD, the operating principle of a membrane degasser differs from other types of membranes (reverse osmosis, ultrafiltration). In the space of the degasser membranes, there is no flow of liquid through the membrane pores. The membrane is an inert gas-tight wall that serves as a separator for the liquid and gaseous phases.

Expert opinion

Features of the application of groundwater ozonation technology

V.V. Dzyubo,

L.I. Alferova,

Senior Researcher, Department of Water Supply and Sanitation, Tomsk State University of Architecture and Civil Engineering

How effective ozonation will be as a technology for water treatment and purification of groundwater is influenced not only by the parameters of ozone synthesis: electrical energy costs, price, etc. It is also important how effectively the mixing and dissolution of ozone occurs in the water undergoing treatment. We should not forget about the quality composition.

Cold water is more suitable for better dissolution of ozone, and the substance disintegrates faster when the temperature of the aquatic environment rises. As saturation pressure increases, ozone also dissolves better. All this needs to be taken into account. For example, ozone dissolves up to 10 times faster in a certain temperature environment than oxygen.

Research related to water ozonation has been repeatedly conducted in Russia and abroad. The results of studies of this water treatment technology showed that the level of water saturation with ozone (the maximum possible concentration) is influenced by the following factors:

• the ratio of the volume of the supplied mixture of ozone and air (m 3) and the amount of treated water Qw (m 3) - (Qoz / Qw);
• ozone concentration in the mixture of ozone and air that is supplied to the water;
• volume of water being treated;
• temperature of the water being treated;
• saturation pressure;
• duration of saturation.

If the source of water supply is groundwater, it should be remembered that it may change depending on the season, in particular its quality becomes different. This must be taken into account when justifying water treatment technologies for organizing public water supply, especially if it uses ozonation.

If ozone is used in groundwater water treatment technologies, one should not forget about significant differences in their quality in different regions of Russia. In addition, the quality of groundwater differs from the composition of previously studied clean water. In this regard, the use of any known water treatment technology or technological parameters for water treatment will be incorrect, since the qualitative composition and specifics of the water to be treated should always be taken into account. For example, there will always be differences between the real or actually achieved ozone concentration in natural groundwater subject to treatment and the theoretically possible or achieved values ​​using clean water. When justifying certain water treatment technologies, a detailed study of the qualitative composition of the water source is required first of all.

Modern water treatment technologies and innovative methods

By introducing new methods and technologies of water treatment, it is possible to solve certain problems, the achievement of which ensures:

• production of drinking water in accordance with GOST and current standards that meet the requirements of customers;
• reliable water purification and disinfection;
• uninterrupted and reliable operation of water treatment facilities;
• reducing the cost of water preparation and purification processes;
• saving reagents, electrical energy and water for personal needs;
• high quality water production.

The latest water treatment technologies that are used to improve water should also be touched upon.

1. Membrane methods

Membrane methods are based on modern water treatment technologies, which include macro- and micro-, ultra- and nanofiltration, as well as reverse osmosis. Membrane water treatment technology is used to desalinate wastewater and solve problems associated with water treatment. At the same time, purified water cannot yet be called useful and safe for the body. Note that membrane methods are expensive and energy-intensive, and their use is associated with constant maintenance costs.

2. Reagent-free methods

Here we should first of all highlight the structuring, or activation, of the liquid as the most frequently used method. Today, there are various methods of activating water (for example, the use of magnetic and electromagnetic waves, cavitation, ultrasonic frequency waves, exposure to various minerals, resonance methods). Using structuring, you can solve a number of problems in water preparation (bleach, soften, disinfect, degas, deferrize water and carry out a number of other manipulations). Chemical water treatment technologies are not used.

Activated water and liquid to which traditional water treatment technologies have been applied are different from each other. The disadvantages of traditional methods have already been mentioned earlier. The structure of activated water is similar to the structure of water from a spring, “living” water. It has many healing properties and great benefits for the human body.

To remove turbidity (thin suspensions that are difficult to settle) from a liquid, another method of activated water is used - its ability to accelerate the coagulation (adhesion and sedimentation) of particles and the subsequent formation of large flakes. Chemical processes and crystallization of dissolved substances occur much faster, absorption becomes more intense, and there is an improvement in the coagulation of impurities and their precipitation. In addition, such methods are often used to prevent the formation of scale in heat exchange equipment.

Water quality is directly affected by the activation methods and water treatment technologies used. Among them:

• magnetic water treatment devices;
• electromagnetic methods;
• cavitation;
• resonant wave structuring of liquid (this water treatment technology is non-contact, and is based on piezocrystals).

3. Hydromagnetic systems

The purpose of HMS (hydromagnetic systems) is to process water flows using a constant magnetic field of a special spatial configuration. HMS is used to neutralize scale in heat exchange equipment, as well as to clarify water (for example, after disinfection with chlorine). This system works like this: metal ions in water interact with each other at a magnetic level. At the same time, chemical crystallization occurs.

Treatment using hydromagnetic systems does not require chemical reagents, and therefore this cleaning method is environmentally friendly. But there are also disadvantages to GMS. As part of this water treatment technology, permanent powerful magnets are used, which are based on rare earth elements that retain their parameters (magnetic field strength) for a long time (decades). But if these elements overheat above 110-120 o C, the magnetic properties may weaken. In this regard, the installation of hydromagnetic systems should be carried out in places where the water temperature does not exceed these values, i.e. before it is heated (return line).

So, the disadvantages of HMS include the possibility of use at a temperature of no more than 110-120 o C, insufficient efficiency, and the need to use other methods with it, which is unprofitable from an economic point of view.

4. Cavitation method

During cavitation, cavities (cavities or cavitation bubbles) are formed in water, inside which there is gas, steam or a mixture of them. During cavitation, water passes into another phase, that is, it turns from liquid to vapor. Cavitation appears when the pressure in the water decreases. A change in pressure is caused by an increase in its speed (with hydrodynamic cavitation), the passage of acoustic water during the rarefaction half-period (with acoustic cavitation).

When cavitation bubbles suddenly disappear, water hammer occurs. As a result, a compression and tension wave is created in water at ultrasonic frequency. The cavitation method is used to purify water from iron, hard salts and other substances that exceed the maximum permissible concentration. At the same time, water disinfection by cavitation is not very effective. Other disadvantages of using the method include significant energy consumption and expensive maintenance with consumable filter elements (resource from 500 to 6000 m 3 of water).

Technologies for water treatment of drinking water for housing and communal services according to the scheme

Scheme 1.Aeration-degassing - filtration - disinfection

This water treatment technology can be called the simplest from a technological point of view and constructive in implementation. The scheme is implemented using different methods of aeration and degassing - it all depends on the qualitative composition of the groundwater. Here are two key uses of this water treatment technology:

• aeration-degassation of liquid in the initial state in the tank; forced air supply and subsequent filtration using granular filters and disinfection by UV irradiation are not used. During aeration-degassing, spraying is carried out onto a hard contact layer using ejector nozzles and vortex nozzles. A contact pool, a water tower, etc. can act as a reservoir of initial water. The filters here are albitophyres and burnt rocks. This technology is usually used to purify groundwater that contains mineral forms of dissolved Fe 2 + and Mn 2 + that do not contain H 2 S, CH 4 and anthropogenic pollutants;
• aeration-degassing, carried out in a similar way to the previous method, but with the additional use of forced air supply. This method is used if the groundwater contains dissolved gases.

Purified water can be supplied to special RWCs (clean water reservoirs) or towers, which are special storage tanks, provided that they have not already been used as a receiving tank. The water is then transported to consumers via distribution networks.

Scheme 2.Aeration-degassing - filtration - ozonation - filtration on GAC - disinfection

As for this water treatment technology, its use is advisable for complex purification of groundwater if there are strong contaminants in high concentrations: Fe, Mn, organic matter, ammonia. During this method, single or double ozonation is carried out:

• if there are dissolved gases CH 4, CO 2, H 2 S, organic matter and anthropogenic pollution in the water, ozonation is carried out after aeration-degassing with filtration using inert materials;
• if there is no CH 4, at (Fe 2 +/Mn 2 +)< 3: 1 озонирование нужно проводить на первом этапе аэрации-дегазации. Уровень доз озона в воде не должен быть выше 1,5 мг/л, чтобы не допустить окисления Mn 2 + до Mn 7 +.

You can use the filter materials indicated in diagram A. If sorption purification is used, activated carbon and clinoptilolite are often used.

Scheme 3. Aeration-degassing - filtration - deep aeration in vortex aerators with ozonation - filtration - disinfection

This technology develops the technology for purifying groundwater according to scheme B. It can be used to purify waters that contain elevated levels of Fe (up to 20 mg/l) and Mn (up to 3 mg/l), petroleum products up to 5 mg/l, phenols up to 3 µg/l and organics up to 5 mg/l with the pH of the source water close to neutral.

Within this water treatment technology, it is best to use UV irradiation to disinfect purified water. Territories for bactericidal installations can be:

• places located directly before the supply of purified water to consumers (if the length of the networks is short);
• right in front of the water points.

Taking into account the quality of groundwater from a sanitary point of view and the state of the water supply system (networks, structures on them, RHF, etc.), equipping stations or water treatment equipment for the purpose of disinfecting water before supplying it to consumers may imply the presence any equipment acceptable for the conditions of a particular territory.

Scheme 4.Intensive degassing-aeration - filtration (AB; GP) - disinfection (Ural irradiation)

This water treatment technology includes stages of intensive degassing-aeration and filtration (sometimes two-stage). The use of this method is advisable when it is necessary to remove dissolved CH 4, H 2 S and CO 2, which are present in high concentrations with a fairly low content of dissolved forms of Fe and Mn - up to 5 and 0.3 mg/l, respectively.

As part of the application of water treatment technology, enhanced aeration and filtration are performed in 1-2 stages.

To perform aeration, they use vortex nozzles (in relation to individual systems), vortex degassers - aerators, combined degassing and aeration units (columns) with simultaneous removal of gases.

As for filter materials, they are similar to those indicated in scheme A. When the groundwater contains phenols and petroleum products, filtration is carried out using sorbents - activated carbons.

In accordance with this scheme, water is filtered using two-stage filters:

• 1st stage - to purify water from Fe and Mn compounds;
• 2nd stage - to carry out sorption purification of water, which has already been purified, from petroleum products and phenols.

If possible, only the first stage of filtering is performed, due to which the circuit becomes more flexible. At the same time, the implementation of such water treatment technology requires more costs.

If we are considering small and medium-sized settlements, the use of this water treatment technology is preferable in the pressure version.

As part of the application of water treatment technology, you can use any method of disinfection of water that has already been purified. It all depends on how productive the water supply system is and what are the conditions of the territory where the water treatment technology is used.

Scheme 5.Ozonation - filtration - filtration - disinfection (NaClO)

If it is necessary to remove anthropogenic and natural contaminants, they resort to ozonation with further filtration through a granular load and adsorption on GAC and disinfection with sodium hypochlorite when the total iron content in the water is up to 12 mg/l, potassium permanganate is up to 1.4 mg/l and oxidability is up to 14 mg O 2 /l.

Scheme 6.Aeration-degassing - coagulation - filtration - ozonation - filtration - disinfection (NaClO)

This option is similar to the previous scheme, but here aeration-degassing is used and a coagulant is introduced before the deferrization and demanganization filters. Thanks to water treatment technology, it is possible to remove anthropogenic pollutants in a more complex situation, when the level of iron reaches up to 20 mg/l, manganese up to 4 mg/l and there is high permanganate oxidation - 21 mg O 2 /l.

Scheme 7.Aeration-degassing - filtration - filtration - ion exchange - disinfection (NaClO)

This scheme is recommended for areas of Western Siberia where there are significant oil and gas deposits. As part of the water treatment technology, water is freed from iron, sorbtion is carried out on GAC, ion exchange is carried out on clinoptilolite in Na-form with further disinfection and sodium hypochlorite. Let us note that the scheme is already being successfully used in Western Siberia. Thanks to this water treatment technology, the water complies with all SanPiN 2.1.4.1074-01 standards.

Water treatment technology also has disadvantages: periodically, ion exchange filters must be regenerated using a solution of table salt. Accordingly, the issue of destruction or secondary use of the regeneration solution arises here.

Scheme 8. Aeration-degassation - filtration (C + KMnO 4) - ozonation - sedimentation - adsorption (C) - filtration (C + KMnO 4) (demanganation) - adsorption (C) - disinfection (Cl)

Thanks to the water treatment technology according to this scheme, heavy metals, ammonium, radionuclides, anthropogenic organic pollutants, etc., as well as manganese and iron are removed from the water in two stages - using coagulation and filtration through loading from natural zeolite (clinoptilolite), ozonation and sorption on zeolite . Regenerate the load using the reagent method.

Scheme 9. Aeration-degassation - ozonation - filtration (clarification, iron removal, demanganation) - adsorption on GAC - disinfection (Ural irradiation)

Within the framework of this water treatment technology, the following activities are carried out:

• Methane is completely removed with a concomitant increase in pH as a result of partial stripping of carbon dioxide, hydrogen sulfide, as well as volatile organochlorine compounds (VOC), preozonation, oxidation of preozonation and hydrolysis of iron are performed (deep aeration-degassation stage);
• 2-3-valent iron and iron phosphate complexes, partially manganese and heavy metals are removed (filtration stage of water treatment technology);
• destroy residual persistent complexes of iron, potassium permanganate, hydrogen sulfide, anthropogenic and natural organic substances, sorption of ozonation products, nitrify ammonium nitrogen (ozonation and sorption stage).

Purified water must be disinfected. To do this, UV irradiation is performed, a small dose of chlorine is introduced, and only then the liquid is supplied to the water distribution networks.

Expert opinion

How to choose the right water treatment technology

V.V. Dzyubo,

Dr. Tech. Sciences, Professor of the Department of Water Supply and Sanitation, Tomsk State University of Architecture and Civil Engineering

From an engineering point of view, it is quite difficult to design water treatment technologies and draw up technological schemes according to which it is necessary to bring water to drinking standards. The determination of the method of processing groundwater as a separate stage in the development of a general water treatment technology is influenced by the qualitative composition of natural waters and the required depth of purification.

Groundwater in Russian regions is different. It is on their composition that water treatment technologies and achieving water compliance with drinking standards depend on SanPiN 2.1.4.1074-01 “Drinking water. Hygienic requirements for water quality of centralized drinking water supply systems. Quality control. Sanitary and epidemiological rules and regulations.” The water treatment technologies used, their complexity and, of course, the cost of purification equipment also depend on the initial quality and content of drinking water.

As already noted, the composition of waters is different. Its formation is influenced by the geographic, climatic, and geological conditions of the area. For example, the results of natural studies of the composition of waters in different territories of Siberia indicate that they have different characteristics in different seasons, since their nutrition changes depending on the time of year.

When the conditions for the extraction of groundwater from aquifers are violated, water flows from neighboring horizons, which also affects the change in characteristics and qualitative composition of liquids.

Since the choice of one or another water treatment technology depends on the characteristics of water, it is necessary to analyze their composition in detail and completely in order to choose the least expensive and most effective option.

Today you can get clean water at home or at a large production enterprise in a variety of ways. Thanks to the development of science and technology, consumers have access to both chemical and physical options for obtaining not only softened water, but also absolutely purified water. Basic water treatment methods That’s why they require study, because knowledge is power

Water treatment method: disinfection

Homemade options for obtaining purified water are always contrasted with industrial ones. Of course, with the current development, home options cannot withstand the competition. But some segments of the population continue to use them, focusing on their cheapness. Still, buying a separate one at first glance seems like an expensive pleasure. It's always easier to do prevention. But as practice shows, the basic methods of water treatment have long since become obsolete.

The table below presents all the methods that can be used to disinfect water or eliminate the effects of hardness at home.

Home methods of water disinfection have one significant drawback: in most cases, they fight not the cause, but the consequences. This is best illustrated by the example of softness. Water, as is known in the central water supply, is hard, and only the consumer himself can take care of bringing it to the required level.

He only controls cash. Thus, treatment with citric acid helps soften the light coating that has formed on the walls of the equipment. And that's provided that it's small. If the scale is already stagnant, then citric acid or the same vinegar or essence will no longer help. That is, there is no readily available and convenient substance that can soften the water, and not eliminate the scale that has already formed. And that means home remedies are definitely not helpful here. Hardness is, however, one of the most important reasons for using softening and cleaning systems. After all, the central water supply is rarely concerned about the degree of lime in the water supplied to the end consumer.

However, the state of the water cannot be ignored either. This threatens with very unpleasant consequences. Moreover, a person understands why it is necessary to eliminate solid debris or iron salts, but why hardness is so dangerous and harmful is not always the case. This is the main reason for not giving due attention to everyone. Only the industry has long ago assessed the degree of harm caused by scale, and eliminates it regularly and strives to install softening systems.

There are several reasons why the average consumer should provide himself and his family with soft water:

• She is useful;
• It is economical;
• It does not damage household appliances

The set of methods is standard, but effective. If a consumer starts using soft water, he will very soon realize how much he has saved. Hard water itself does not dissolve detergents well. Because of this, the funds are spent many times more. And the water itself. The quality of washing decreases dramatically. You don't have to look far for examples. Everyone has seen stains on clothes after washing. This is all the work of lime water.

But the worst thing is that the scale formed by such water itself acts as a high-quality heat insulator. At the same time, it settles on heated surfaces and heating elements. What is the result? Very dire consequences. Scale covers the surfaces and heat does not escape into the water. More precisely, it leaves, but no more than 15 percent of the total. But according to the law of conservation, it cannot disappear without a trace. So it remains inside the surfaces, which, when heated, melt or burst. Therefore, you definitely cannot take disinfection at home lightly. There is a risk of being left without the entire set of household appliances. And, as a rule, the teapot is the first to suffer from such consequences. Only consumers are more likely to blame the low-quality manufacturer. And only when a washing machine or boiler breaks down do people begin to think about purchasing disinfection units for their apartment.

In industry, things are different. Any heating network or boiler room depends on the quality of water. And a slight deposit of scale can destroy all efforts to provide hot water and heating. And even a small amount of scale can lead to boiler failure. And this is not a washing machine. This is a lot of money. Until there were various filters for disinfection, cleaning and rinsing were widely used in this area. But they were not very effective. After all, no matter how much you clean the surface, it does not become whole. Therefore, when various softening methods appeared, all industries tried to switch to their use, if there were enough funds.

Methods of water treatment in modern realities

With such shortcomings of both home water treatment methods and simple purification rituals, the use of other options has become the only possible defense mechanism against water deficiencies. Which is what is widely used today. Although any method has its disadvantages and advantages. Even their areas of application are somewhat different. More precisely, simply using one or another method is more cost-effective in a certain area. This is how expensive membrane reverse osmosis pays off in the production of drinking water. And electromagnetic radiation has a positive effect when working with boiler rooms.

It makes sense to consider modern ones in the same sequence as the location of water treatment stages. During the initial water intake and a high degree of contamination, purification will begin with the mechanical removal of all solid impurities, down to grains of sand. Today, this method is represented by various modern devices, from a simple oblique mud trap to sophisticated and complex industrial mechanical mud traps. The main purpose of mechanical cleaning is to eliminate any solid particles to avoid rapid wear and tear of water handling equipment. The longevity of the devices depends on the nature of the contaminants and the strength of the filter meshes or the type of treatment backfill used.

After mechanical cleaning, the stage of eliminating specific impurities begins. These include metal salts, including ferrous and manganese salts. The essence of the water treatment method is to make slightly soluble salts from dissolved salts in water. They will then form a precipitate and can be easily filtered out. To do this, soluble forms of salt must be oxidized. To do this, use aeration or use other stronger chemical oxidizers for chemical devices. Very often, potassium permanganate can be used as an oxidizing agent at this stage. Filter elements are chosen in a variety of ways, depending on the resulting sediment.

Another very basic method of water treatment is softening which deals with the removal of calcium and magnesium salts from water. To eliminate them, cationic resins, membranes, or magnetic force fields enhanced by electrical impulses are used. When working with resins, their exchange capacity quickly depletes, and the cartridges have to be replaced. Or restore it, but then there is a problem with waste disposal.

When working with membrane devices, it is necessary to solve problems with post-treatment. Membrane treatment refers to fine cleaning, and it is impossible to send untreated water into such a device. Because of this, it costs much more, but it produces practically distilled water.

Electromagnetic treatment not only helps soften water, it helps solve problems with the deposition of old and new lime deposits. No human intervention is required. Neither the use of any additional substances. For thermal power engineering, these devices have become indispensable, because help keep equipment surfaces clean. Such devices are also gaining popularity in everyday life.

To eliminate impurities such as odors, turbidity and color, ordinary activated carbon is most often used. It is also often used for drinking water at home. Especially when the amount of chlorine in the water is off scale.

Another one relates to the elimination of nitrates using specially created anion exchangers formed with ordinary salt. The same reverse osmosis can replace this process. Which, despite its high cost, allows it to maintain a leading position among cleaning methods. After all, it eliminates almost one hundred percent of impurities.

And one more method is extremely important. This is disinfection; there should be no bacteria or viruses in the water at all. Either chemicals or ultraviolet irradiation will help eliminate them. There is also the option of ozonation, but due to difficulties with its production, it is not yet widely used, although without a doubt it is the best from the point of view of environmental safety.

Water is absolutely necessary for human life and all living things in nature. Water covers 70% of the earth's surface, these are: seas, rivers, lakes and groundwater. During its cycle, determined by natural phenomena, water collects various impurities and contaminants that are contained in the atmosphere and on the earth’s crust. As a result, water is not absolutely pure and pure, but often this water is the main source both for domestic and drinking water supply and for use in various industries (for example, as a coolant, working fluid in the energy sector, solvent, feedstock for receiving products, food, etc.)

Natural water is a complex disperse system, which contains large quantities of various mineral and organic impurities. Due to the fact that in most cases the sources of water supply are surface and groundwater.

Composition of ordinary natural water:

• suspended substances (colloidal and coarse mechanical impurities of inorganic and organic origin);
• bacteria, microorganisms and algae;
• dissolved gases;
• dissolved inorganic and organic substances (both dissociated into cations and anions, and undissociated).

When assessing the properties of water, it is customary to divide water quality parameters into:

• physical,
• chemical
• sanitary and bacteriological.

Quality means compliance with the standards established for a given type of water production. Water and aqueous solutions are very widely used in various industries, public utilities and agriculture. Requirements for the quality of purified water depend on the purpose and area of ​​application of the purified water.

Water is most widely used for drinking purposes. The requirements standards in this case are determined by SanPiN 2.1.4.559-02. Drinking water. Hygienic requirements for water quality of centralized drinking water supply systems. Quality control" . For example, some of them:

Tab. 1. Basic requirements for the ionic composition of water used for domestic and drinking water supply

For commercial consumers, water quality requirements are often stricter in some respects. For example, for the production of bottled water, a special standard has been developed with more stringent requirements for water - SanPiN 2.1.4.1116-02 “Drinking water. Hygienic requirements for the quality of water packaged in containers. Quality control". In particular, the requirements for the content of basic salts and harmful components - nitrates, organics, etc. have been tightened.

Water for technical and special purposes is water for use in industry or commercial purposes, for special technological processes - with special properties regulated by the relevant standards of the Russian Federation or the technological requirements of the Customer. For example, preparing water for energy (according to RD, PTE), for electroplating, preparing water for vodka, preparing water for beer, lemonade, medicine (pharmacopoeial monograph), etc.

Often, the requirements for the ionic composition of these waters are much higher than for drinking water. For example, for thermal power engineering, where water is used as a coolant and is heated, there are appropriate standards. For power plants there are so-called PTE (Technical Operation Rules), for general thermal power engineering the requirements are set by the so-called RD (Guide Document). For example, according to the requirements of the “Methodological guidelines for the supervision of the water chemical regime of steam and hot water boilers RD 10-165-97”, the value of the total water hardness for steam boilers with a working steam pressure of up to 5 MPa (50 kgf/cm2) should be no more 5 mcg-eq/kg. At the same time, the drinking standard SanPiN 2.1.4.559-02 requires that Jo be no higher than 7 mEq/kg.

Therefore, the task of chemical water treatment (CWT) for boiler houses, power plants and other facilities that require water treatment before heating water is to prevent the formation of scale and the subsequent development of corrosion on the inner surface of boilers, pipelines and heat exchangers. Such deposits can cause energy losses, and the development of corrosion can lead to a complete stop in the operation of boilers and heat exchangers due to the formation of deposits on the inside of the equipment.

It should be borne in mind that the technologies and equipment for water treatment and water treatment for power plants differ significantly from the corresponding equipment of conventional hot water boiler houses.

In turn, technologies and equipment for water treatment and chemical treatment for obtaining water for other purposes are also diverse and are dictated by both the parameters of the source water to be purified and the requirements for the quality of purified water.

SVT-Engineering LLC, having experience in this field, possessing qualified personnel and partnerships with many leading foreign and domestic specialists and firms, offers its clients, as a rule, those solutions that are appropriate and justified for each specific case, in in particular, based on the following basic technological processes:

• The use of inhibitors and reagents for water treatment in various chemical treatment systems (both to protect membranes and thermal power equipment)

Most technological processes for treating water of various types, including waste water, have been known and used for a relatively long time, constantly changing and improving. However, leading specialists and organizations around the world are working on the development of new technologies.

SVT-Engineering LLC also has experience in conducting R&D on behalf of clients in order to increase the efficiency of existing water purification methods, develop and improve new technological processes.

It should be especially noted that the intensive use of natural water sources in economic activities necessitates the environmental improvement of water use systems and water treatment technological processes. Requirements for the protection of the natural environment require the maximum reduction of waste from water treatment plants into natural reservoirs, soil and atmosphere, which also necessitates the need to supplement the technological schemes of water treatment with stages of waste disposal, recycling and conversion into recyclable substances.

To date, a fairly large number of methods have been developed that make it possible to create low-waste water treatment systems. First of all, these include improved processes for preliminary purification of source water with reagents in clarifiers with lamellas and sludge recirculation, membrane technologies, demineralization based on evaporators and thermochemical reactors, corrective treatment of water with inhibitors of salt deposits and corrosion processes, technologies with countercurrent regeneration of ion exchange filters and more advanced ion exchange materials.

Each of these methods has its own advantages, disadvantages and limitations of their use in terms of the quality of source and purified water, the volume of wastewater and discharges, and parameters for the use of purified water. You can obtain additional information necessary to solve your problems and terms of cooperation by making a request or contacting our office.