is a complex of special structures designed to purify wastewater from the contaminants it contains. Purified water is either used further or discharged into natural reservoirs (Great Soviet Encyclopedia).
Every settlement needs effective wastewater treatment plants. The operation of these complexes determines what water will enter the environment and how this will subsequently affect the ecosystem. If liquid waste is not cleaned up at all, not only will plants and animals die, but the soil will also be poisoned, and harmful bacteria can enter the human body and cause serious consequences.
Every enterprise that has toxic liquid waste is required to operate a treatment plant system. Thus, this will affect the state of nature and improve human living conditions. If treatment systems work effectively, wastewater will become harmless when it enters the ground and water bodies. The size of treatment facilities (hereinafter - OS) and the complexity of treatment strongly depend on the contamination of wastewater and its volume. More details about the stages of wastewater treatment and types of O.S. read on.
The most indicative in terms of the presence of water purification stages are urban or local OS, designed for large populated areas. It is household wastewater that is most difficult to treat, as it contains various pollutants.
It is typical for sewerage water treatment facilities that they are built in a certain sequence. Such a complex is called a treatment plant line. The scheme begins with mechanical cleaning. Grates and sand traps are most often used here. This is the initial stage of the entire water treatment process.
This could be leftover paper, rags, cotton wool, bags and other debris. After the grates, sand traps come into operation. They are necessary in order to retain sand, including large sizes.
Initially, all water from the sewer enters the main pumping station into a special reservoir. This reservoir is designed to compensate for the increased load during peak hours. A powerful pump evenly pumps the appropriate volume of water to pass through all stages of cleaning.
catch large debris larger than 16 mm - cans, bottles, rags, bags, food, plastic, etc. Subsequently, this waste is either processed on site or transported to sites for processing solid household and industrial waste. The gratings are a type of transverse metal beams, the distance between which is several centimeters.
In fact, they catch not only sand, but also small pebbles, glass fragments, slag, etc. Sand settles to the bottom quite quickly under the influence of gravity. Then the settled particles are raked by a special device into a recess at the bottom, from where they are pumped out. The sand is washed and disposed of.
. Here all impurities that float to the surface of the water (fats, oils, petroleum products, etc.) are removed. By analogy with a sand trap, they are also removed with a special scraper, only from the surface of the water.
4. Settling tanks– an important element of any treatment plant line. In them, water is freed from suspended substances, including helminth eggs. They can be vertical and horizontal, single-tier and two-tier. The latter are the most optimal, since in this case the water from the sewer in the first tier is purified, and the sediment (silt) that has formed there is discharged through a special hole into the lower tier. How does the process of releasing suspended solids from sewer water take place in such structures? The mechanism is quite simple. Sedimentation tanks are large, round or rectangular shaped tanks where substances settle under the influence of gravity.
To speed up this process, you can use special additives - coagulants or flocculants. They promote the sticking together of small particles due to a change in charge; larger substances settle faster. Thus, sedimentation tanks are indispensable structures for purifying water from sewers. It is important to take into account that they are also actively used in simple water treatment. The principle of operation is based on the fact that water enters from one end of the device, while the diameter of the pipe at the exit becomes larger and the flow of liquid slows down. All this contributes to the sedimentation of particles.
mechanical wastewater treatment can be used depending on the degree of water contamination and the design of a specific treatment facility. These include: membranes, filters, septic tanks, etc.
If we compare this stage with conventional water treatment for drinking purposes, then in the latter version such structures are not used and there is no need for them. Instead, processes of water clarification and discoloration occur. Mechanical cleaning is very important, since in the future it will allow for more effective biological treatment.
Biological treatment can be either an independent treatment facility or an important stage in a multi-stage system of large urban treatment complexes.
The essence of biological treatment is to remove various pollutants (organics, nitrogen, phosphorus, etc.) from water using special microorganisms (bacteria and protozoa). These microorganisms feed on harmful contaminants contained in the water, thereby purifying it.
From a technical point of view, biological treatment is carried out in several stages:
– a rectangular tank where water, after mechanical purification, is mixed with activated sludge (special microorganisms), which purifies it. Microorganisms are of 2 types:
Necessary for removing unpleasantly smelling air with its subsequent purification. This workshop is necessary when the volume of wastewater is large enough and/or treatment facilities are located near populated areas.
Here the water is purified from activated sludge by settling it. Microorganisms settle to the bottom, where they are transported to the pit using a bottom scraper. A surface scraper mechanism is provided to remove floating sludge.
The purification scheme also includes sludge digestion. The most important treatment facility is the digester. It is a reservoir for the fermentation of sludge, which is formed during settling in two-tier primary settling tanks. During the fermentation process, methane is produced, which can be used in other technological operations. The resulting sludge is collected and transported to special sites for thorough drying. Sludge beds and vacuum filters are widely used for sludge dewatering. After this, it can be disposed of or used for other needs. Fermentation occurs under the influence of active bacteria, algae, and oxygen. The sewer water purification scheme may also include biofilters.
It is best to place them before the secondary settling tanks, so that substances that are carried away with the flow of water from the filters can settle in the settling tanks. It is advisable to use so-called pre-aerators to speed up cleaning. These are devices that help saturate water with oxygen to accelerate aerobic processes of oxidation of substances and biological treatment. It should be noted that sewerage water purification is conventionally divided into 2 stages: preliminary and final.
The treatment plant system may include biofilters instead of filtration and irrigation fields.
- These are devices where wastewater is purified by passing through a filter containing active bacteria. It consists of solid substances, which can be granite chips, polyurethane foam, polystyrene foam and other substances. A biological film consisting of microorganisms forms on the surface of these particles. They decompose organic matter. As biofilters become dirty, they need to be cleaned periodically.
Wastewater is fed into the filter in doses, otherwise high pressure can destroy beneficial bacteria. After biofilters, secondary settling tanks are used. The sludge formed in them goes partly into the aeration tank, and the rest of it goes to the sludge compactors. The choice of one or another biological treatment method and type of treatment facility largely depends on the required degree of wastewater treatment, topography, soil type and economic indicators. 
After passing through the main stages of treatment, 90-95% of all contaminants are removed from wastewater. But the remaining pollutants, as well as residual microorganisms and their metabolic products, do not allow this water to be discharged into natural reservoirs. In this regard, various wastewater treatment systems were introduced at wastewater treatment plants.
In bioreactors the process of oxidation of the following pollutants occurs:
This happens by creating conditions for the development of autotrophic microorganisms, i.e. converting inorganic compounds into organic ones. For this purpose, special plastic backfill discs with a high specific surface area are used. Simply put, these are disks with a hole in the center. To speed up processes in the bioreactor, intensive aeration is used.
Filters purify water using sand. The sand is continuously updated automatically. Filtration is carried out in several installations by supplying water to them from the bottom up. In order to avoid using pumps and not wasting electricity, these filters are installed at a level lower than other systems. Filter washing is designed in such a way that it does not require a large amount of water. Therefore, they do not occupy such a large area.
Disinfection or disinfection of water is an important component that ensures its safety for the body of water into which it will be discharged. Disinfection, that is, the destruction of microorganisms, is the final stage of sewerage wastewater treatment. A wide variety of methods can be used for disinfection: ultraviolet irradiation, alternating current, ultrasound, gamma irradiation, chlorination.
Ural irradiation is a very effective method that destroys approximately 99% of all microorganisms, including bacteria, viruses, protozoa, and helminth eggs. It is based on the ability to destroy the membrane of bacteria. But this method is not used so widely. In addition, its effectiveness depends on the turbidity of the water and the content of suspended substances in it. And UV lamps quickly become covered with a coating of mineral and biological substances. To prevent this, special emitters of ultrasonic waves are provided.
The most commonly used method after treatment facilities is chlorination. Chlorination can be different: double, superchlorination, with preammonization. The latter is necessary to prevent unpleasant odors. Superchlorination involves exposure to very large doses of chlorine. Double action means that chlorination is carried out in 2 stages. This is more typical for water treatment. The method of chlorinating sewer water is very effective, in addition, chlorine has an aftereffect that other cleaning methods cannot boast of. After disinfection, the wastewater is discharged into a reservoir.
Phosphates are salts of phosphoric acids. They are widely used in synthetic detergents (washing powders, dishwashing detergents, etc.). Phosphates entering water bodies lead to their eutrophication, i.e. turning into a swamp.
Purification of wastewater from phosphates is carried out by dosed addition of special coagulants to the water before biological treatment facilities and before sand filters.
is the active process of saturating water with air, in this case by passing air bubbles through the water. Aeration is used in many processes in wastewater treatment plants. Air supply is carried out by one or more blowers with frequency converters. Special oxygen sensors regulate the amount of air supplied so that its content in the water is optimal.
At the biological stage of wastewater treatment, excess sludge is formed, as microorganisms actively multiply in aeration tanks. Excess sludge is dewatered and disposed of.
The dehydration process takes place in several stages:
Unfortunately, wastewater treatment plants don't smell the best. The biological wastewater treatment stage is especially smelly. Therefore, if the treatment plant is located near populated areas or the volume of wastewater is so large that a lot of bad-smelling air is generated, you need to think about cleaning not only the water, but also the air.
Air purification usually takes place in 2 stages:
All water that leaves treatment plants must be systematically monitored in the laboratory. The laboratory determines the presence of harmful impurities in water and whether their concentrations comply with established standards. If one or another indicator is exceeded, treatment plant workers conduct a thorough inspection of the corresponding treatment stage. And if a malfunction is detected, it is eliminated.
The personnel servicing the treatment plant can reach several dozen people. For their comfortable work, an administrative and amenity complex is being created, which includes:
Power supply O.S. performed according to the first reliability category. Since a long shutdown of O.S. due to lack of electricity may cause O.S. output. out of service.
To prevent emergency situations, power supply O.S. carried out from several independent sources. The branch of the transformer substation provides for the input of a power cable from the city power supply system. As well as the introduction of an independent source of electric current, for example, from a diesel generator, in case of an emergency in the city power grid.
Based on all of the above, we can conclude that the design of treatment facilities is very complex and includes various stages of treating wastewater from sewers. First of all, you need to know that this scheme applies only to domestic wastewater. If industrial wastewater occurs, then in this case special methods are additionally included that will be aimed at reducing the concentration of hazardous chemicals. In our case, the cleaning scheme includes the following main stages: mechanical, biological cleaning and disinfection (disinfection).
Mechanical cleaning begins with the use of grates and sand traps, which trap large debris (rags, paper, cotton wool). Sand traps are needed to sediment excess sand, especially coarse sand. This is of great importance for subsequent stages. After screens and sand traps, the sewer water treatment plant scheme includes the use of primary settling tanks. Suspended substances settle in them under the force of gravity. To speed up this process, coagulants are often used.
After settling tanks, the filtration process begins, which is carried out mainly in biofilters. The mechanism of action of the biofilter is based on the action of bacteria that destroy organic substances.
The next stage is secondary settling tanks. The silt that was carried away by the current of liquid settles in them. After them, it is advisable to use a digester, in which the sludge is fermented and transported to sludge sites.
The next stage is biological treatment using an aeration tank, filtration fields or irrigation fields. The final stage is disinfection.
A variety of structures are used for water treatment. If it is planned to carry out this work on surface water immediately before its supply to the city’s distribution network, then the following structures are used: settling tanks, filters. For wastewater, a wider range of devices can be used: septic tanks, aeration tanks, digesters, biological ponds, irrigation fields, filtration fields, and so on. There are several types of treatment plants depending on their purpose. They differ not only in the volume of water being purified, but also in the presence of stages of its purification.
Data from O.S. are the largest of all, they are used in large cities and towns. In such systems, particularly effective methods of liquid purification are used, for example, chemical treatment, methane tanks, flotation units. They are designed for the treatment of municipal wastewater. These waters are a mixture of domestic and industrial wastewater. Therefore, there are a lot of pollutants in them, and they are very diverse. The water is purified to meet the standards for discharge into a fishery reservoir. The standards are regulated by Order of the Ministry of Agriculture of Russia dated December 13, 2016 No. 552 “On approval of water quality standards for water bodies of fishery importance, including standards for maximum permissible concentrations of harmful substances in the waters of water bodies of fishery importance.”
In OS data, as a rule, all stages of water purification described above are used. The most illustrative example is the Kuryanovsky wastewater treatment plant.
Kuryanovsky O.S. are the largest in Europe. Its capacity is 2.2 million m3/day. They serve 60% of Moscow's wastewater. The history of these objects goes back to 1939.
Local treatment facilities are structures and devices designed to treat the subscriber's wastewater before discharging it into the public sewerage system (defined by Decree of the Government of the Russian Federation of February 12, 1999 No. 167).
There are several classifications of local OS, for example, there are local OS. connected to the central sewerage and autonomous. Local O.S. can be used on the following objects:
Local O.S. can vary greatly from small units to capital structures that are maintained daily by qualified personnel.
Several solutions are used to dispose of wastewater from a private home. They all have their advantages and disadvantages. However, the choice always remains with the home owner.
1. Cesspool. In truth, this is not even a treatment facility, but simply a tank for temporary storage of wastewater. When the pit is filled, a sewage disposal truck is called, which pumps out the contents and takes it away for further processing.
This archaic technology is still used today due to its cheapness and simplicity. However, it also has significant disadvantages, which sometimes negate all its advantages. Wastewater can enter the environment and groundwater, thereby polluting it. It is necessary to provide a normal entrance for the sewer truck, since it will have to be called quite often.
2. Storage. It is a container made of plastic, fiberglass, metal or concrete into which wastewater is drained and stored. They are then pumped out and disposed of by a sewer truck. The technology is similar to a cesspool, but the water does not pollute the environment. The disadvantage of such a system is the fact that in the spring, when there is a large amount of water in the ground, the storage tank can be squeezed out to the surface of the earth.
3. Septic tank- are large containers, in which substances such as coarse dirt, organic compounds, stones and sand precipitate, and elements such as various oils, fats and petroleum products remain on the surface of the liquid. The bacteria that live inside the septic tank extract oxygen for life from the fallen sediment, while reducing the level of nitrogen in the wastewater. When the liquid leaves the sump, it becomes clarified. It is then purified using bacteria. However, it is important to understand that phosphorus remains in such water. For final biological treatment, irrigation fields, filtration fields or filter wells can be used, the operation of which is also based on the action of bacteria and activated sludge. Plants with a deep root system cannot be grown in this area.
A septic tank is very expensive and can take up a large area. It should be borne in mind that this is a structure that is designed to treat small amounts of domestic wastewater from the sewer system. However, the result is worth the money spent. The structure of a septic tank is shown more clearly in the figure below. 
4. Deep biological treatment stations are already a more serious treatment facility, unlike a septic tank. This device requires electricity to operate. However, the quality of water purification is up to 98%. The design is quite compact and durable (up to 50 years of operation). To service the station, there is a special hatch at the top, above the ground surface.
Despite the fact that rainwater is considered quite clean, it collects various harmful elements from asphalt, roofs and lawns. Garbage, sand and petroleum products. To ensure that all this does not end up in nearby water bodies, stormwater treatment facilities are being created.
In them, water undergoes mechanical purification in several stages:
Design of O.S. determine their cost, choose the right treatment technology, ensure reliable operation of the structure, and bring wastewater to quality standards. Experienced specialists will help you find effective installations and reagents, draw up a wastewater treatment plan and put the installation into operation. Another important point is drawing up an estimate that will allow you to plan and control expenses, as well as make adjustments if necessary.
For the project O.S. The following factors greatly influence:
Stages of designing a treatment plant:
After the O.S. project has been prepared and all necessary permits have been obtained, the installation stage begins. Although the installation of a country septic tank is very different from the construction of a sewage treatment plant in a cottage community, they still go through several stages.
First, the area is prepared. A pit is being dug to install a treatment plant. The floor of the pit is filled with sand and compacted or concreted. If a treatment plant is designed for a large amount of wastewater, then, as a rule, it is built on the surface of the ground. In this case, the foundation is poured and a building or structure is already installed on it.
Secondly, the installation of equipment is carried out. It is installed, connected to the sewerage and drainage system, and to the electrical network. This stage is very important because it requires personnel to know the specifics of the operation of the equipment being configured. It is incorrect installation that most often causes equipment failure.
Thirdly, inspection and delivery of the object. After installation, the finished treatment facility is tested for the quality of water treatment, as well as for its ability to operate under high load conditions. After checking O.S. is handed over to the customer or his representative, and also, if necessary, undergoes a state control procedure.
Like any equipment, the treatment plant also needs maintenance. Primarily from O.S. It is necessary to remove large debris, sand, and excess silt that are formed during cleaning. On large O.S. the number and type of elements removed can be significantly greater. But in any case, they will have to be deleted.
Secondly, the functionality of the equipment is checked. Malfunctions in any element can lead not only to a decrease in the quality of water purification, but also to the failure of all equipment.
Thirdly, if a breakdown is detected, the equipment must be repaired. And it’s good if the equipment is under warranty. If the warranty period has expired, then repair O.S. you will have to do it at your own expense.
One of the main objectives of the enterprise is the effective purification of water obtained from natural surface sources in order to provide residents with high-quality drinking water. The classic technological scheme used at Moscow water treatment stations allows this task to be accomplished. However, ongoing trends in the deterioration of water quality in water sources due to anthropogenic impact and the tightening of drinking water quality standards dictate the need to increase the degree of purification.
With the beginning of the new millennium in Moscow, for the first time in Russia, in addition to the classical scheme, highly efficient innovative technologies for the preparation of drinking water of a new generation are being used. Projects of the 21st century are modern treatment plants, in which classical technology is supplemented with ozonation and sorption processes on activated carbon. Thanks to ozone sorption, water is better purified from chemical contaminants, unpleasant odors and tastes are eliminated, and additional disinfection occurs.
The use of innovative technologies eliminates the influence of seasonal changes in the quality of natural water, ensures reliable deodorization of drinking water, and its guaranteed epidemic safety even in cases of emergency contamination of the water supply source. In total, about 50% of all treated water is prepared using new technologies.
Along with the introduction of new methods of water purification, disinfection processes are being improved. In order to increase the reliability and safety of drinking water production by eliminating liquid chlorine from circulation, in 2012 the transition of all water treatment stations to a new reagent - sodium hypochlorite was completed. In connection with the tightening of state standards for the content of chloroform in drinking water, a targeted development of disinfection regimes was carried out, as a result why the concentration of chloroform in Moscow tap water, according to average data for 2018, did not exceed 5 - 13 μg/l, with the standard being 60 μg/l.
Technological schemes for the purification of artesian waters are individual for each facility, taking into account the characteristics of the water quality of the exploited aquifers and contain the following steps: deferrization; softening; water conditioning using carbon sorption filters; removal of heavy metal impurities; disinfection with sodium hypochlorite or using ultraviolet lamps.
Today, in the Troitsky and Novomoskovsky administrative districts of Moscow, about half of the water intake units supply water that has undergone technological processing.
The phased introduction of new technologies is carried out in accordance with the General Scheme for the development of the water supply system, which provides that the complete reconstruction of all water treatment facilities will make it possible to supply water of the highest quality to all residents of the Moscow metropolis.
Block-modular water treatment stations VOS are designed for receiving and purifying artesian water to SanPiN 2.1.41074-01 “Drinking Water” standards. The stations' productivity ranges from 50 to 800 m³/day. The delivery set includes a pumping station for supplying water to the consumer. Delivery of UGS clean water tanks is carried out upon separate request.
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VOS water treatment stations are one-story metal block-modular buildings with a gable roof. The frame of the station blocks is made of steel square pipes 100x100x4 and channels No. 10. The roof is gable, made on beams from channels No. 10. The enclosing structures of buildings are the walls and roof of a complex structure:
The floors are made of corrugated aluminum sheets, grade AMg2NR, δ=4 mm. All stations are equipped with electric lighting, a heating and ventilation system, and a process automation system.
VOS stations are installed on a reinforced concrete foundation slab (the design of the slab is determined by calculation) and are welded to the embedded parts.
A blind area 1 m wide is provided around the stations. External drainage of water from the roof is organized through drainage gutters and pipes.
Linking a station to a project is carried out only after the customer provides a source water analysis protocol.
If there are indicators of source water that are not indicated in the table above and exceed the standards of SanPiN 2.1.41074-01 “Drinking Water”, adjustments to the purification technology and equipment composition are required.
| Parameter name | VOS-50 | VOS-100 | VOS-200 | VOS-400 | VOS-800 |
| The daily productivity of the station is no more than m3/day. | 50 | 100 | 200 | 400 | 800 |
| Station hourly productivity, m 3 /hour | 2,1 | 4,2 | 8,3 | 17 | 33,3 |
| Characteristics of the pumping station for supplying water to the consumer, flow rate m 3 /hour (pressure, m) |
11,7 (50) |
13,7 (51) |
27 (58) |
50 (50) |
140 (30) |
| Overall dimensions of the station, no more (length x width x height), m | 6x6x3 | 6x6x3 | 6x6x3 | 9x6x3 | 9x9x3 |
| Number of block modules, pcs./dimensions, m | 2 pcs. 6x3 |
2 pcs. 6x3 |
2 pcs. 6x3 |
2 pcs. 9x3 |
3 pcs. 9x3 |
| Parameter name | VOS-50 | VOS-100 | VOS-200 | VOS-400 | VOS-800 |
| Installed power* of electrical equipment, kW | 23,9 | 27,2 | 40,3 | 59,3 | 78,7 |
| Installed power* of electrical equipment (without heating equipment), kW | 12,4 | 15,7 | 28,8 | 47,8 | 67,2 |
| Power consumption* for the technological needs of the station, kW | 4,6 | 6,1 | 10,8 | 19,1 | 31 |
| Filter washing intensity, l/m 2 *s | 16 | 16 | 16 | 16 | 16 |
| Water consumption for filter washing, m 3 /hour | 6 | 14 | 27 | 39,2 | 39,2 |
| Volume of water for one filter wash (6 min), m3 | 0,6 | 1,4 | 2,7 | 3,9 | 3,9 |
| Consumption of sodium hypochlorite, l/month. | 8,6 | 17,2 | 34,4 | 68,8 | 137,6 |
* - taking into account the pumping station for supplying water to the consumer.
Natural water is a complex system containing many different mineral and organic impurities.
The quality of water and the suitability of its use for various purposes is assessed using a set of indicators. When using water from underground sources for drinking water supply, the main regulated indicators are: the content of total iron and manganese in the water, permanganate oxidation, color, turbidity and the presence of pathogenic microorganisms.
Bringing these indicators up to drinking water quality standards is carried out at water treatment stations of the block-modular type.
The technological diagram of a water treatment station includes the following main elements:
The type of equipment used depends on the composition of the groundwater supplied to the water treatment station from the water supply source.
Source groundwater from wells is supplied to the water receiving tank (WRT), located inside the station. Supply to the RPV is carried out by free flow. As a result of contact of water with atmospheric oxygen, oxidation and release of iron and manganese compounds from the water in the form of insoluble impurities occurs.
Water is supplied from the reservoir using pumps for treatment.
To remove undissolved impurities from purified water, a FE(T) filter with hydroanthracite-based loading is used. This material has high dirt holding capacity and at the same time low density compared to other filter materials. Due to its low density, washing this filter material requires less water consumption.
To remove organic substances from purified water and improve the organoleptic properties of water (taste, smell, color), a CA(T) filter is used. The SA series filters use coconut activated carbon as a filter media. Activated carbon is made from coconut shells and has high sorption capacity and high mechanical strength.
Water supply for filter washing is provided by water supply pumps to the consumer during hours of minimum water consumption. After washing the filters, water is discharged into the on-site sewerage system. After sorption filters, to prevent the removal of filter material, barrier fine filters are installed.
Purified water enters clean water tanks (CWT). The RHF capacity provides storage of:
Purified water is supplied for disinfection and then to the consumer using dry installation pumps.
Water disinfection is the process of destroying microorganisms found there. Up to 98% of bacteria are retained during the water purification process. But among the remaining bacteria, as well as among the viruses, there may be pathogenic (disease-causing) microbes, the destruction of which requires special water treatment
The process of disinfection of purified water occurs before supplying water to the network in an ultraviolet installation equipped with a sensor of ultraviolet radiation and its power.
For periodic disinfection of the clean water reservoir and water supply networks, it is necessary to dose sodium hypochlorite solution into the water.
The installation for preparing and dispensing a disinfecting solution includes a supply tank and a dosing pump. Dosing of the reagent solution is provided in the water intake pipeline from the RHF and in the water supply pipeline to the RHF.
As a result of the implementation of the proposed technological scheme for processing source groundwater, the quality of purified drinking water will meet the requirements of SanPiN 2.1.4.1074-01 "Drinking Water".
Before entering the city water supply networks and consumer taps, the water undergoes thorough pre-treatment. To make it drinkable, water treatment stations are installed, which allow you to remove all harmful impurities, garbage, and chemical elements unsafe for health. However, even the most high-tech installations do not guarantee cleanliness, so additional home filters are often used.
Most city residents are not satisfied with the quality of water supplied through water mains to their taps. Moreover, in different regions the chemical composition of the liquid and the presence of impurities in it differ. Some people note increased hardness, others notice a white residue due to chalk, and sometimes there is a distinct smell of mold or other strange substances. The solution to the problem in most cases is the installation of storage or flow filters.
In fact, before reaching direct consumers, residents of populated areas, industrial and other facilities, water undergoes thorough purification. The procedure during which it is brought into compliance with sanitary standards is called water treatment. Drinking water at the station is supplied from natural reservoirs, storage facilities, and canals. The process of its processing depends on its further use: drinking, domestic use, watering or technical needs.
In certain settlements or regions, municipal chemical water treatment plants operate. These are large stationary facilities or mobile complexes represented by container, modular and block systems.
The design of each installation depends on what needs to be purified from the water. Based on the filtering method, the following types of stations are distinguished:
All systems are also classified into household and industrial, differing in performance and operating principle. Many urban facilities install several filter systems that perform different functions simultaneously.
On the way from the reservoir to the apartment, water flows go through several stages of purification. However, you should not be sure that it becomes perfectly clean and safe. In the summer heat, the number of harmful bacteria and microorganisms increases significantly. It is precisely because of the consumption of tap water that there is a surge in intestinal diseases and poisoning. In frosty weather, the amount of pathogenic microflora is significantly reduced, but the human factor and negligence of employees of water treatment plants, worn-out equipment and other problems cannot be discounted.
The standard procedure at a water treatment plant occurs in several stages:
The final stage is passing through carbon filters. They improve the color and smell of water and make the taste more pleasant.
A mandatory procedure at any water treatment plant is disinfection - the destruction of bacteriological pollutants . Chlorine is used as reagents or ultraviolet sterilization units. However, in the first case, an additional procedure is required to get rid of chlorine residues, which are extremely dangerous to health.
Ultraviolet rays are considered safer. They are able to penetrate every cell of microorganisms, destroy them and completely destroy them. Thus, the maximum disinfecting effect is achieved. In most cities, preference is still given to flushing intracity networks with chlorine. This is evidenced by the periodically appearing characteristic odor for several days, twice a year.
Stationary stations are huge sites with numerous components and mechanisms. Modern equipment operates fully automatically, so human presence in the work process is reduced to a minimum. The standard equipment of the devices includes:
There are several types of stations. The most primitive ones are block-type structures with closed systems that operate on the principle of pumping equipment.
The most modern installations are complex, modular, multi-stage structures that include disinfection, filtration, and other stages, and are equipped with distribution channels and outlets. An important feature of such systems is the possibility of their integration into large industrial facilities, as well as changing the set of modules and components.
Another type is specialized, highly targeted stations that only perform the destruction of bacteria, fungi, and algae.
When choosing equipment it is necessary to focus on different criteria. For example, at home, installations with a throughput capacity of 2−3 m3/hour are sufficient. For industrial facilities, this figure should be calculated from the daily requirement and amount to up to 1 thousand m3/hour. The optimal pressure is considered to be in the range from 6 to 10 bar for large hydrological units; for domestic needs it is determined individually.
After using tap water that has been purified in urban stationary facilities, deposits are often observed, for example, in a kettle, on sinks or in a washing machine. This is a light limescale deposit that needs to be cleaned regularly to prevent it from turning into limestone. Drinking water of this quality is dangerous to health, as sooner or later it leads to the formation of kidney stones. Household appliances also suffer from this liquid composition. Washing machines and dishwashers quickly fail when scale regularly forms on the heating elements.
These are not all the problems that arise as a result of using low-quality water in domestic conditions. Therefore, there are additional costs associated with installing mini cleaning stations in your home or apartment.
One of the areas of application of water treatment plants is beer production enterprises. Here, very strict requirements are imposed on the liquid; it is the main raw material. To obtain 1 liter of intoxicating drink you will need 20 liters of water. The taste of the finished product, its durability, softness, and the fermentation process depend on its quality.
Due to the increase in water consumption and the insufficiency of groundwater sources, surface water sources taken from rivers and reservoirs are used for water supply purposes.
The quality of drinking water is subject to requirements in accordance with the norms of the current standard. High demands are also placed on the quality of water used for technological purposes of industrial enterprises, since this leads toin many waysthe normal functioning of industrial units and workshop equipment depends.
Water quality inwater supply sources often does not meet the requirements, so the task of improving it arises. Improving the quality of natural water for household and drinking needs and technological purposes is achieved by various special methods of its processing (purification). In order to improve the quality of drinking water and its purification, special water pipelines are being built as part of modern water supply systems.complexes of treatment facilities , combined intowater treatment plants .
Wastewater also require cleaning in order to eliminate their harmful effects on the external environment (reservoirs, soil, groundwater, air) and through it on people, animals, fish, plants.Cleaning of drains is one of the most important measures to protect nature, rivers and reservoirs from pollution. It is produced at special complexessewage treatment plants . These structures not only purify water from pollutants, but also capture useful substances for use in the main production (industry) or for use as raw materials in other industries.
The required degree of purification of wastewater discharged into reservoirs of the Russian Federation is regulated by the “Rules for the protection of surface waters from pollution by wastewater” and “Fundamentals of water legislation of the Russian Federation”.
In construction practice, complexes are builttreatment facilities two main types -water supply Andsewer . Each of these types of treatment facilities has its own varieties, as well as specific features both in the composition and design of individual structures, and in the technological processes occurring in them.
The method of water treatment and the composition of water treatment facilities depend on the quality of the source water, the requirements for the quality of drinking water, and the adopted technological scheme for its purification.
Technological processes for water purification includelightening , bleaching Anddisinfection . In this case, the water is coagulated, settled and filtered, and is also treated with chlorine. If the quality of the source water allows one to abandon some technological processes of its treatment, the complex of structures is reduced accordingly.
Studyingtechnological schemes for drinking water purification shows that the main methods of clarification and decolorization of water onwater treatment facilities are sedimentation and filtration with preliminary treatment of water with reagents (coagulants). To settle water, mainly horizontal (less often vertical) settling tanks or clarifiers with suspended sediment are used, and for filtration, filters with various types of filter media or contact clarifiers are used.
In the practice of water supply construction in our country, the most widespreadwater treatment plants , designed, but with a technological scheme that provides horizontal settling tanks and rapid filters as the main treatment facilities.
Accepted singletechnological scheme for drinking water purification predetermined the almost identical composition of the main and auxiliary structures. So, for example, in all complexeswater treatment plants , regardless of their performance and type, the following structures are included:reagent facility with mixer , reaction chambers ( flocculation ), horizontal settling tanks orclarifiers , filters,reservoirs for clean water , pumping station II lift with an electrical substation, as well as auxiliary (production), administrative, technical, cultural and community facilities.
. , like water pipelines, are complex complexes of engineering structures interconnected by the technological process of wastewater treatment. At treatment plants, wastewater is subjected to mechanical, chemical and biochemical (biological) treatment.
In progressmechanical cleaning Suspended substances and coarse mechanical impurities are separated from the liquid phase of wastewater by straining, settling and filtering. In some cases, mechanical cleaning is final. But most often it only serves as a preparation for further, for example, biochemical purification.
The complex of treatment facilities designed formechanical treatment of domestic wastewater , include: gratings designed to retain large substances of organic and mineral origin; sand traps for separating heavy mineral contaminants (mainly fishing line); settling tanks for separating settling substances (mainly organic); chlorination plant with contact tanks in which clarified wastewater comes into contact with chlorine in order to destroy pathogenic bacteria. As a result of processing incoming wastewater at these facilities, they aretheirdisinfection can be discharged into the reservoir.
Scheme of chemical wastewater treatment differs from the mechanical one by introducing a mixer and reagent facilities in front of the settling tanks. In this case, the treated wastewater, after the grates and sand trap, enters the mixer, where a coagulation reagent is added to it, and then into the settling tank for clarification. Wastewater from the settling tank is discharged either directly into the reservoir, or first on a filter for additional clarification, and thenVwater. Facilities for treating sludge during chemical treatment are the same. as with mechanical.
Biochemical wastewater treatment, depending on local conditions, is usually carried out on three main construction schemes: on irrigation fields or filtration fields, on biofilters and in aeration tanks. In the first scheme, wastewater, having passed through the grates, enters sand traps and then into settling tanks for clarification and deworming, from where it is sent to irrigation fields or filtration fields and then to the reservoir. In the second scheme, wastewater first passes through mechanical treatment and pre-aeration facilities (pre-aerators), then it enters bio-filters, and then into a secondary settling tank to separate substances carried out by the sludge of biofilters from the purified water. Cleaning ends with disinfection of wastewater before discharge into the reservoir. In the third scheme, preliminary treatment of wastewater is carried out on screens, sand traps, pre-aerators and settling tanks. Their subsequent cleaning is carried out in aeration tanks, then in secondary settling tanks and ends with disinfection, after which the water is discharged into the reservoir. The choice of the type of facilities for biochemical wastewater treatment is made depending on a number of factors, including; the required degree of wastewater treatment, the size of the area for treatment facilities (a larger area is required for the construction of irrigation fields and much smaller for aeration tanks), the nature of the soil, the topography of the area, etc. The design of treatment facilities is selected taking into account economic indicators - construction -body and operational cost of structures.
