WASTE WATER TREATMENT FACILITIES.

Wastewater treatment plants, as the name suggests, are designed to treat wastewater. Their main purpose is to treat wastewater to a level suitable for further use. Wastewater treatment methods are diverse and depend on the type of wastewater, pollutants and pollution levels.

Purification - treatment with the aim of destroying or removing harmful substances from wastewater. Removing wastewater from pollution is a rather complex process that can be compared to production. It contains raw materials (waste water) and finished products (purified water).

Wastewater treatment plants are installed on various types of wastewater.

Domestic waste water - formed as a result of human activity. The effluent comes from plumbing fixtures (washbasins, sinks, toilets, etc.) of residential buildings, institutions, public buildings. Household wastewater is dangerous because it is a breeding ground for pathogenic bacteria.

Industrial effluent - are formed in enterprises. This category is characterized by the possible presence of various impurities, some of which significantly complicate the cleaning process. Industrial wastewater treatment plants are usually complex in design, have several stages of treatment. The composition of such structures is selected in accordance with the composition of the effluent. Industrial waste water can be toxic, acidic, alkaline, with mechanical impurities.

Storm drains - because of the method of formation, they are also called superficial. This type of effluent is a liquid that collects on roofs, roads, and squares during precipitation. Storm wastewater treatment facilities usually include several stages and are capable of removing various types of impurities from the liquid, mainly mechanical and sorption treatment. Storm runoff is the least hazardous and least contaminated of all.

Water purification systems are vital for human settlements. The consequences of the discharge of untreated wastewater are devastating to nature. Dirty water entering the reservoir destroys the established ecosystem: the death of aquatic plants, microorganisms, fish, soil poisoning occurs. The damage is done to pets, and ultimately to human health.

In 2010, modern equipment was installed - filter presses. Thanks to the new units, the volume of sludge treated has increased.

Is a complex of special structures designed to clean wastewater from the contaminants it contains. Purified water is either used in the future or discharged into natural reservoirs (Great Soviet Encyclopedia).

Every locality needs effective treatment facilities. The operation of these complexes determines what kind of water will enter the environment and how this will further affect the ecosystem. If liquid waste is not cleaned at all, then not only plants and animals will die, but the soil will also be poisoned, and harmful bacteria can enter the human body and cause serious consequences.

Each enterprise that has toxic liquid waste is obliged to deal with a system of treatment facilities. Thus, it will reflect on the state of nature, and improve human living conditions. If the treatment complexes work effectively, then wastewater will become harmless when it gets into the ground and water bodies. The size of treatment facilities (hereinafter referred to as OS) and the complexity of treatment strongly depend on the pollution of wastewater and their volumes. More details about the stages of wastewater treatment and types of O.S. read on.

Wastewater treatment stages

The most indicative in terms of the presence of stages of water purification are urban or local OS, designed for large settlements. It is household wastewater that is most difficult to purify, as it contains diverse pollutants.

For sewage treatment plants, it is characteristic that they are built in a certain sequence. Such a complex is called a line of treatment facilities. The scheme starts with mechanical cleaning. Here, gratings and sand traps are most often used. This is the initial stage of the entire water treatment process.

These can 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 ones.

Mechanical stage of wastewater treatment

Initially, all water from the sewage system goes to the main pumping station in 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 for all stages of cleaning.

catch large debris over 16 mm - cans, bottles, rags, bags, food, plastic, etc. In the future, this waste is either processed on site, or taken out to places where solid household and industrial waste is processed. Lattices are a type of transverse metal beams, the distance between which is equal to several centimeters.

In fact, they catch not only sand, but also small stones, glass fragments, slag, etc. The sand settles to the bottom rather quickly under the influence of gravity. Then the settled particles are raked into a recess at the bottom by a special device, from where they are pumped out by a pump. The sand is washed and disposed of.

... It removes all impurities that float to the surface of the water (fats, oils, oil products, etc.), etc. By analogy with a sand trap, they are also removed with a special scraper, only from the water surface.

4. Sediments - an important element of any line of wastewater treatment plants. They release water from suspended solids, including helminth eggs. They can be vertical and horizontal, single-tier and two-tier. The latter are the most optimal, since the water from the sewerage system in the first tier is purified, and the sediment (sludge) that has formed there is discharged through a special hole into the lower tier. How does the process of releasing water from the sewage system from suspended solids occur in such structures? The mechanism is pretty simple. Sediment tanks are large-sized tanks of round or rectangular shape, where sedimentation of substances occurs under the influence of gravity.

To speed up this process, you can use special additives - coagulants or flocculants. They promote adhesion of small particles due to a change in charge, larger substances precipitate faster. Thus, sedimentation tanks are irreplaceable structures for water purification from sewage systems. It is important to take into account that they are also actively used for 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 outlet becomes larger and the fluid flow slows down. All this contributes to the deposition of particles.

mechanical wastewater treatment can be used depending on the degree of water pollution and the design of a particular treatment plant. 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, they are not necessary. Instead, the processes of water clarification and discoloration take place. Mechanical cleaning is very important, as in the future it will allow more efficient biological cleaning.

Biological wastewater treatment plant

Biological treatment can be both an independent treatment plant and an important stage in a multistage system of large urban treatment complexes.

The essence of biological treatment is to remove various pollutants (organic matter, nitrogen, phosphorus, etc.) from the water using special microorganisms (bacteria and protozoa). These microorganisms feed on harmful impurities 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 cleaning is mixed with activated sludge (special microorganisms), which purifies it. Microorganisms are of 2 types:

• Aerobic - using oxygen for water purification. When using these microorganisms, the water must be enriched with oxygen before entering the aerotank.
• Anaerobic - DO NOT use oxygen for water purification.

It is necessary to remove unpleasant smelling air and then purify it. This workshop is necessary when the volume of wastewater is large enough and / or treatment facilities are located near settlements.

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 the floating sludge.

The cleaning scheme also includes sludge digestion. Of the treatment facilities, a digester is important. It is a reservoir for the fermentation of sludge, which is formed during settling in two-tier primary sedimentation tanks. The digestion process generates methane that can be used in other processing steps. The resulting sludge is collected and transported to special areas for thorough drying. Sludge platforms and vacuum filters are widely used for sludge dewatering. After that, it can be disposed of or used for other needs. Fermentation occurs under the influence of active bacteria, algae, oxygen. Biofilters may also be included in the sewage water treatment scheme.

It is best to place them before the secondary sedimentation tanks, so that substances that are carried away with the water flow from the filters can settle in the sedimentation tanks. It is advisable to use the so-called pre-aerators to speed up the cleaning. These are devices that contribute to the saturation of water with oxygen to accelerate the aerobic processes of oxidation of substances and biological treatment. It should be noted that water purification from the sewage system is conventionally divided into 2 stages: preliminary and final.

The treatment plant system can include biofilters instead of filtration and irrigation fields.

- these are devices where wastewater is treated by passing through a filter containing active bacteria. It consists of solid substances, which can be granite chips, polyurethane foam, foam and other substances. On the surface of these particles, a biological film is formed, consisting of microorganisms. They decompose organic matter. Biofilters need to be cleaned periodically as they become dirty.

Waste water is fed into the filter in a metered dose, otherwise a high pressure can destroy beneficial bacteria. After biofilters, secondary sedimentation tanks are used. The sludge formed in them enters partly into the aeration tank, and the rest of it goes to the sludge compactors. The choice of one or another method of biological treatment and the type of treatment facilities largely depends on the required degree of wastewater treatment, relief, type of soil and economic indicators.

Wastewater post-treatment

After passing 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 waste products, do not allow this water to be discharged into natural water bodies. In this regard, various systems for additional wastewater treatment were introduced at the treatment facilities.

In bioreactors, the following pollutants are oxidized:

• organic compounds that were too tough for microorganisms,
• these microorganisms themselves,
• ammonium nitrogen.

This happens by creating conditions for the development of autotrophic microorganisms, i.e. converting inorganic compounds into organic. For this, special plastic filling discs with a high specific surface area are used. Simply put, these are discs with a hole in the center. Intensive aeration is used to speed up the processes in the bioreactor.

Filters purify water using sand. The sand is continuously updated in automatic mode. Filtration is carried out in several installations by supplying water to them from the bottom up. In order not to use pumps and not consume electricity, these filters are installed at a level lower than other systems. Filters are flushed in such a way that it does not require a lot of water. Therefore, they do not occupy such a large area.

Ultraviolet water disinfection

Disinfection or disinfection of water is an important component that ensures its safety for the reservoir into which it will be discharged. Disinfection, that is, the destruction of microorganisms, is the final stage in the purification of sewage drains. A variety of methods can be used for disinfection: ultraviolet irradiation, alternating current, ultrasound, gamma irradiation, chlorination.

UFO is a very effective method by which about 99% of all microorganisms are destroyed, including bacteria, viruses, protozoa, helminth eggs. It is based on the ability to destroy the membrane of bacteria. But this method is not widely used. In addition, its effectiveness depends on the turbidity of the water, the content of suspended solids in it. And the UFO lamps quickly become covered with a coating of mineral and biological substances. To prevent this, special emitters of ultrasonic waves are provided.

The chlorination method is most often used after treatment facilities. Chlorination is different: double, superchlorination, with preammonization. The latter is necessary to prevent unpleasant odors. Superchlorination involves exposure to very high doses of chlorine. The double action is that the chlorination is carried out in 2 stages. This is more typical for water treatment. The method of chlorination of water from the sewage system is very effective, in addition, chlorine has an aftereffect, which other cleaning methods cannot boast. After disinfection, the effluent is drained into the reservoir.

Phosphate removal

Phosphates are salts of phosphoric acids. They are widely used in synthetic detergents (washing powders, dishwashing detergents, etc.). Phosphates, getting into water bodies, lead to their eutrophication, i.e. turning into a swamp.

Wastewater purification from phosphates is carried out by the dosed addition of special coagulants to the water in front of biological treatment facilities and in front of sand filters.

Auxiliary rooms of treatment facilities

Aeration workshop

Is an active process of saturating water with air, in this case by passing air bubbles through the water. Aeration is used in many processes in sewage 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.

Disposal of excess activated sludge (microorganisms)

At the biological stage of wastewater treatment, excess sludge is formed, since microorganisms in aeration tanks actively multiply. Excess sludge is dewatered and disposed of.

The dehydration process takes place in several stages:

1. The excess sludge is added special reagentswhich suspend the activity of microorganisms and contribute to their thickening
2. IN sludge compactor sludge is compacted and partially dewatered.
3. On the centrifuge the sludge is squeezed out and the remaining moisture is removed from it.
4. In-line dryers with the help of continuous circulation of warm air, the sludge is finally dried. The dried sludge has a residual moisture content of 20-30%.
5. Then ooze packed in sealed containers and disposed of
6. The water removed from the sludge is sent back to the beginning of the cleaning cycle.

Air cleaning

Unfortunately, sewage treatment plants don't smell their best. Particularly smelly is the biological wastewater treatment stage. Therefore, if the treatment plant is located near settlements 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 water, but also air.

Air purification usually takes place in 2 stages:

1. The initially polluted air is fed into bioreactors, where it comes into contact with a specialized microflora adapted for the disposal of organic matter contained in the air. It is these organic substances that cause the bad smell.
2. The air goes through a stage of disinfection with ultraviolet light to prevent these microorganisms from entering the atmosphere.

Wastewater treatment plant laboratory

All water that leaves the treatment plant must be systematically controlled in the laboratory. The laboratory determines the presence of harmful impurities in the water and the compliance of their concentration with the established standards. If one or another indicator is exceeded, the workers of the treatment plant conduct a thorough examination of the corresponding cleaning stage. And in case of a malfunction, they eliminate it.

Administrative complex

The personnel serving the treatment plant can reach several dozen people. For their comfortable work, an administrative and amenity complex is being created, it includes:

• Equipment repair workshops
• Laboratory
• Control room
• Offices of administrative and managerial personnel (accounting, HR, engineering, etc.)
• Head office.

Power supply O.S. performed according to the first category of reliability. Since the long stoppage of the work of O.S. due to lack of electricity can cause the OS to go out. out of service.

To prevent emergencies, the power supply of O.S. carried out from several independent sources. In the department of the transformer substation, it is planned to enter a power cable from the city power supply system. And also the input of an independent source of electric current, for example, from a diesel generator, in case of an accident in the city power grid.

Conclusion

Based on the foregoing, it can be concluded that the scheme of treatment facilities is very complex and includes various stages of wastewater treatment from the sewage system. First of all, you need to know that this scheme applies only to domestic wastewater. If there are industrial effluents, then in this case they additionally include special methods 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 gratings and sand traps, in which large debris (rags, paper, cotton wool) is retained. Sand traps are needed to sediment excess sand, especially coarse sand. This is of great importance for the subsequent steps. After the grates and sand traps, the sewage treatment plant scheme includes the use of primary sedimentation tanks. Suspended substances settle in them under the force of gravity. To speed up this process, coagulants are often used.

After the sedimentation 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 matter.

The next stage is secondary sedimentation tanks. In them, the sludge, which was carried away with the flow of liquid, settles. After them, it is advisable to use a digester, in which sediment is fermented and transported to sludge pads.

The next stage is biological treatment using an aerotank, filtration fields or irrigation fields. The final stage is disinfection.

Types of treatment facilities

A variety of structures are used for water treatment. If it is planned to carry out these works in relation to surface waters immediately before their supply to the distribution network of the city, then the following structures are used: sedimentation tanks, filters. A wider range of devices can be used for wastewater: septic tanks, aeration tanks, digestion tanks, biological ponds, irrigation fields, filtration fields, and so on. Treatment facilities are of several types, depending on their purpose. They differ not only in the volumes of purified water, but also in the presence of stages of its purification.

Urban Wastewater Treatment Plant

O.S. are the largest of all, they are used in large metropolitan areas and cities. In such systems, especially 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 waters are purified to the standards of discharge into the fishery water body. The standards are regulated by the order of the Ministry of Agriculture of Russia dated December 13, 2016 No. 552 "On the approval of water quality standards for water bodies of fishery significance, including standards for maximum permissible concentrations of harmful substances in the waters of water bodies for fishery significance."

On OS data, as a rule, all stages of water purification described above are used. The most illustrative example is the Kuryanovsk treatment plant.

Kuryanovskie O.S. are the largest in Europe. Its capacity is 2.2 million m3 / day. They serve 60% of the wastewater in Moscow. The history of these objects goes back to 1939.

Local treatment facilities

Local treatment facilities are structures and devices intended for the treatment of subscriber's wastewater before being discharged into the municipal sewage system (the definition is given by the 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 OS can be used at the following facilities:

• In small towns
• In villages
• In sanatoriums and boarding houses
• At car washes
• On personal plots
• At manufacturing plants
• And at other sites.

Local OS can be very different from small units to permanent structures, which are serviced by qualified personnel on a daily basis.

Treatment facilities for a private house.

Several solutions are used for the disposal of wastewater from a private house. They all have their own advantages and disadvantages. However, the choice always rests with the owner of the house.

1. Cesspool... In truth, this is not even a sewage treatment plant, but just a temporary storage tank. When the pit is filled, a sewer truck is called, which pumps out the contents and takes them for further processing.

This archaic technology is still used today because of its cheapness and simplicity. However, it also has significant drawbacks, which, at times, negate all its advantages. Wastewater can enter the environment and groundwater, thereby polluting it. For a sewage truck, you need to provide for a normal entrance, since you will have to call it quite often.

2. Storage... It is a container made of plastic, fiberglass, metal or concrete, where waste water is drained and stored. Then they are pumped out and disposed of by a sewer truck. The technology is similar to a cesspool, but the waters do not pollute the environment. The disadvantage of such a system is the fact that in the spring with a large amount of water in the ground, the drive can be squeezed out to the surface of the earth.

3. Septic tank - is a large container, in which substances such as coarse dirt, organic compounds, stones and sand leave in the sediment, and elements such as various oils, fats and oil products remain on the surface of the liquid. The bacteria that live inside the septic tank extract oxygen for life from the precipitated sediment, while reducing the level of nitrogen in the wastewater. When the liquid leaves the sump, it becomes clarified. Then it is purified with 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 work of which is also based on the action of bacteria and activated sludge. It will not be possible to grow deep-rooted plants in this area.

The 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 a small amount of domestic wastewater from the sewage system. However, the result is worth the investment. The septic tank device is more clearly reflected in the figure below.

4. Station of deep biological treatment are already a more serious treatment plant in contrast to 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). There is a special hatch above the ground for servicing the station.

Stormwater treatment plant

Despite the fact that rainwater is considered quite clean, it collects various harmful elements from asphalt, roofs and lawns. Garbage, sand and oil products. In order to prevent all this from getting into the nearest water bodies, storm water treatment facilities are being created.

In them, the water undergoes mechanical treatment in several stages:

1. Sump. Here, under the influence of the Earth's gravity, large particles settle to the bottom - pebbles, glass fragments, metal parts, etc.
2. Thin layer module. Here oils and petroleum products are collected on the surface of the water, where they are collected on special hydrophobic plates.
3. Sorption fibrous filter. It picks up everything that the thin layer filter missed.
4. Coalescing module. It promotes the separation of oil particles that float to the surface, the size of which is greater than 0.2 mm.
5. Post-treatment carbon filter. It finally relieves water of all oil products that remain in it after passing through the previous stages of purification.

Wastewater treatment plant design

Design by O.S. determine their cost, choose the right treatment technology, ensure the reliability of the structure, bring wastewater to quality standards. Experienced specialists will help you find effective installations and reagents, draw up a wastewater treatment scheme and commission the installation. Another important point is budgeting, which will allow you to plan and control costs, as well as make adjustments if necessary.

For the project of O.S. the following factors are strongly influenced:

• Waste water volumes. Designing structures for a private plot is one thing, but designing a wastewater treatment plant for a cottage village is another. Moreover, it should be borne in mind that the capabilities of O.S. must be greater than the current amount of wastewater.
• Terrain. Wastewater treatment facilities require a special vehicle entrance. It is also necessary to provide for the power supply of the facility, the discharge of treated water, the location of the sewage system. O.S. may occupy a large area, but they should not interfere with neighboring buildings, structures, road sections and other structures.
• Wastewater pollution.Storm water treatment technology is very different from the treatment of household water.
• Required cleaning level. If the customer wants to save on the quality of the treated water, then it is necessary to use simple technologies. However, if it is necessary to discharge water into natural reservoirs, then the quality of treatment should be appropriate.
• The competence of the performer. If you order OS from inexperienced companies, then get ready for unpleasant surprises in the form of an increase in construction estimates or a septic tank that floated in the spring. This happens because they forget to include critical points in the project.
• Technological features. The technologies used, the presence or absence of treatment stages, the need to build systems serving the treatment plant - all this should be reflected in the project.
• Other. It is impossible to foresee everything in advance. As the design and installation of the treatment plant progresses, various changes may be made to the draft plan that could not have been foreseen at the initial stage.

Treatment plant design stages:

1. Preliminary work. They include the study of the object, clarification of the customer's wishes, analysis of wastewater, etc.
2. Collection of permits. This item is usually relevant for the construction of large and complex structures. For their construction, it is necessary to obtain and agree on the relevant documentation from the supervisory authorities: MOBVU, MOSRYBVOD, Rosprirodnadzor, SES, Hydromet, etc.
3. Choice of technology. On the basis of paragraphs 1 and 2. there is a choice of the necessary technologies used for water purification.
4. Budgeting.Construction costs OS must be transparent. The customer must know exactly how much the materials cost, what is the price of the installed equipment, what is the wage fund for workers, etc. You should also consider the costs of subsequent maintenance of the system.
5. Cleaning efficiency. Despite all calculations, the cleaning results may be far from desired. Therefore, already at the planning stage, O.S. it is necessary to conduct experiments and laboratory studies that will help to avoid unpleasant surprises after the completion of construction.
6. Development and approval of project documentation. To start the construction of treatment facilities, it is necessary to develop and approve the following documents: a project of a sanitary protection zone, a draft of standards for permissible discharges, a project of maximum permissible emissions.

Installation of treatment facilities

After the project of O.S. was prepared and all the necessary permits have been obtained, the stage of installation begins. Although the installation of a summer cottage septic tank is very different from the construction of a sewage treatment plant in a cottage village, they still go through several stages.

First, the terrain is being prepared. A pit is being dug to install a treatment plant. The floor of the pit is covered with sand and compacted, or concreted. If the treatment plant is designed for a large amount of wastewater, then, as a rule, it is built on the surface of the earth. In this case, the foundation is poured and a building or structure is already installed on it.

Secondly, the equipment is being installed. It is installed, connected to the sewerage and sewerage system, to the electrical network. This stage is very important because it requires the personnel to know the specifics of the operation of the equipment being configured. It is the incorrect installation that most often causes equipment failure.

Thirdly, the verification and delivery of the object. After installation, the finished treatment plant is tested for the quality of water purification, as well as for the ability to work under conditions of increased stress. After checking OS. handed over to the customer or his representative, and also, if necessary, undergoes the state control procedure.

Treatment plant maintenance

Like any equipment, a sewage treatment plant also needs maintenance. First of all, from O.S. it is necessary to remove large debris, sand, and excess sludge that are formed during cleaning. On large OS the number and variety of removed elements can be much larger. But in any case, you will have to delete them.

Secondly, the equipment is checked for operability. Malfunctions in any element can be fraught not only with a decrease in the quality of water purification, but also with the failure of all equipment.

Thirdly, in the event of a breakdown, the equipment must be repaired. And it's good if the equipment is under warranty. If the warranty period has expired, then the repair of OS. will have to be done at your own expense.

The Village goes on to explain what the townspeople use every day. In this issue - the sewerage system. After we press the flush button on the toilet, close the faucet and go about our business, the tap water turns into waste water and begins its journey. To get back to the Moskva River, she needs to go through kilometers of sewer networks and several stages of cleaning. How this happens, The Village learned by visiting the city's sewage treatment plant.

Through the pipes

At the very beginning, water enters the inner pipes of the house with a diameter of only 50-100 millimeters. Further along the network goes a little wider - yard, and from there - into the street. At the border of each courtyard network and at the place of its transition to the street, a viewing well is installed through which you can monitor the operation of the network and clean it if necessary.

The length of the city sewer pipes in Moscow is more than 8 thousand kilometers. The entire territory, through which the pipes pass, is divided into pool parts. The section of the network that collects waste water from the pool is called a collector. Its diameter reaches three meters, which is twice as large as a pipe in a water park.

Mainly due to the depth and natural topography of the territory, the water flows through the pipes by itself, but in some places pumping stations are required, there are 156 of them in Moscow.

Wastewater flows to one of four wastewater treatment plants. The cleaning process is continuous, and the peaks of the hydraulic load occur at 12 noon and 12 noon. The Kuryanovsk treatment facilities, which are located near Maryino and are considered one of the largest in Europe, receive water from the southern, southeastern and southwestern parts of the city. Wastewater from the northern and eastern parts of the city goes to treatment plants in Lyubertsy.

Treatment plants

The Kuryanovsk treatment facilities are designed for 3 million cubic meters of wastewater per day, but only one and a half are supplied here. 1.5 million cubic meters is 600 Olympic swimming pools.

Previously, this place was called aeration station, it was launched in December 1950. Now the sewage treatment plant is 66 years old, and 36 of them Vadim Gelievich Isakov worked here. He came here as a foreman of one of the workshops and became the head of the technological department. When asked whether he expected to spend his whole life in such a place, Vadim Gelievich replies that he no longer remembers, it was so long ago.

Isakov says that the station consists of three cleaning blocks. In addition, there is a whole complex of facilities for processing sediments that are formed in the process.

Mechanical cleaning

Turbid and fetid waste water comes to the treatment plant warm. Even in the coldest season, its temperature does not drop below plus 18 degrees. Waste water is met by a receiving and distribution chamber. But what happens there, we will not see: the camera is completely closed so that the smell does not spread. By the way, the smell of the huge (almost 160 hectares) territory of the sewage treatment plants is quite tolerable.

After that, the stage of mechanical cleaning begins. Here, on special grates, debris that floated along with the water lingers. Most often these are rags, paper, personal hygiene products (napkins, diapers), as well as food waste - for example, potato peelings and chicken bones. “What you can not meet. It happened that bones and skins came from meat-processing factories, ”they say with a shudder at the treatment plant. From the pleasant - only gold jewelry, although we did not find eyewitnesses of such a catch. Seeing the trash grid is the worst part of the tour. In addition to all the nasty things, many, many slices of lemons got stuck in it: “You can guess the season by the contents,” the employees say.

A lot of sand comes with wastewater, and so that it does not settle on structures and does not clog pipelines, it is removed in sand traps. Sand in liquid form enters a special area, where it is washed with technical water and becomes normal, that is, suitable for improvement. Sewage treatment plants use sand for their own needs.

The stage of mechanical cleaning in primary sedimentation tanks is being completed. These are large reservoirs in which fine suspended matter is removed from the water. Here water comes in muddy, and leaves clear.

Biological treatment

Biological cleaning begins. It takes place in structures called aerotanks. They artificially support the vital activity of a community of microorganisms, which is called activated sludge. Organic pollution in water is the most desirable food for microorganisms. Air is supplied to the aeration tanks, which does not allow the sludge to settle, so that it comes into contact with waste water as much as possible. This continues for eight to ten hours. “In any natural body of water, similar processes take place. The concentration of microorganisms there is hundreds of times lower than we create. Under natural conditions, this would have lasted weeks and months, ”says Isakov.

The aeration tank is a rectangular tank, divided into sections, in which the waste water snakes in. “If you look through a microscope, then everything is crawling, moving, moving, floating. We make them work for our benefit, ”says our guide.

At the outlet of the aeration tanks, a mixture of purified water and activated sludge is obtained, which now need to be separated from each other. This problem is solved in the secondary sedimentation tanks. There the sludge settles at the bottom, is collected by sludge pumps, after which 90% is returned to the aeration tanks for a continuous cleaning process, and 10% is considered excessive and disposed of.

Return to the river

Biologically treated water is tertiary treated. To check it, it is filtered through a very fine sieve, and then discharged into the outlet channel of the station, on which there is an ultraviolet disinfection unit. Ultraviolet disinfection is the fourth and final cleaning step. At the station, the water is divided into 17 channels, each of which is illuminated by a lamp: the water in this place takes on an acidic hue. This is the most modern and largest such block in the world. Although it did not exist according to the old project, earlier they wanted to disinfect water with liquid chlorine. “It's good that it didn't come to that. We would have destroyed all life in the Moscow River. The reservoir would be sterile, but dead, ”says Vadim Gelievich.

In parallel with water purification, the sludge is dealt with at the station. The sediment from the primary settling tanks and excess activated sludge are processed together. They enter the digesters, where at a temperature of plus 50–55 degrees, the fermentation process takes place for almost a week. As a result, the sediment loses its ability to rot and does not emit an unpleasant odor. Then this sludge is pumped to dewatering complexes outside the Moscow Ring Road. “30–40 years ago, the sediment was dried on sludge areas in natural conditions. This process lasted from three to five years, now instant dehydration. The sediment itself is a valuable mineral fertilizer, in Soviet times it was popular, the state farms took it with pleasure. But now nobody needs it, and the station pays up to 30% of the total cost of cleaning for disposal, ”says Vadim Gelievich.

A third of the sludge breaks down, turning into water and biogas, which saves on disposal costs. Part of the biogas is burned in the boiler house, and part is sent to the combined heat and power plant. A thermal power plant is not an ordinary element of a wastewater treatment plant, but rather a useful addition that gives treatment facilities a relative energy independence.

Fish in the sewer

Previously, an engineering center with its own production base was located on the territory of the Kuryanovskie treatment plants. Employees conducted unusual experiments, for example, they bred sterlet and carp. Some of the fish lived in tap water, and some in the sewer, which was purified. Now fish is found only in the discharge channel, there are even signs "Fishing is prohibited."

After all the purification processes, the water goes through the discharge channel - a small river 650 meters long - to the Moskva River. Here and wherever the process takes place in the open air, there are many seagulls floating on the water. “They do not interfere with the processes, but they spoil the aesthetic appearance,” Isakov is sure.

The quality of the treated wastewater discharged into the river is much better than the water in the river in terms of all sanitary indicators. But drinking such water without boiling is not recommended.

The volume of treated wastewater is equal to about a third of all water in the Moscow River above the discharge. If the sewage treatment plants were out of order, the settlements downstream would be on the brink of ecological disaster. But this is almost impossible.

Sewage treatment facilities OS, KOS, BOS.

One of the main ways to protect the natural environment from pollution is the prevention of untreated water and other harmful components from entering water bodies. Modern treatment facilities are a complex of engineering and technical solutions for the consistent filtration and disinfection of contaminated effluents in order to reuse them in production or for release into natural reservoirs. For this, a number of techniques and technologies have been developed, which will be discussed below.

More about wastewater treatment technology

Since centralized sewerage systems are not laid in all places, and some industrial enterprises require preliminary preparation of effluents, today local sewerage facilities are very often equipped. They are also in demand in private houses, country cottage townships and detached housing estates, industrial enterprises, workshops.

Wastewaters differ in the source of pollution: domestic, industrial and surface (derived from atmospheric precipitation). Domestic waste water is called household waste. They consist of contaminated water removed from showers, toilets, kitchens, canteens and hospitals. In this case, the main pollutants are physiological and household waste.

Industrial effluents include water masses that were formed when:

• performing various production and technological operations;
• washing raw materials and finished products;
• cooling equipment.

Also, this type includes water pumped out from the bowels during the extraction of minerals. Industrial waste is the main source of pollution here. They may include toxic, potentially hazardous substances, as well as waste that can be recovered and used as secondary raw materials.

Surface (atmospheric) drains most often contain only mineral contaminants; minimum requirements are imposed on their treatment. In addition, wastewater is classified according to the concentration of various pollutants. These characteristics influence the choice of the method and the number of cleaning steps. To determine the composition of the equipment, the need for construction, as well as the capacity of various types of structures, a calculation of the production of wastewater treatment is performed.

The main stages of cleaning

At the first stage, mechanical wastewater treatment is carried out, the purpose of which is filtration from various insoluble impurities. For this, special self-cleaning grates and sieves are used. Detained waste, together with other sediments, is sent for further processing or taken to landfills along with solid domestic waste.

In the sand trap, fine particles of sand, slag and other similar mineral elements are deposited under the influence of gravity. In this case, the filtered composition is suitable for further use after processing. The rest of the undissolved substances are reliably retained in special sedimentation tanks and septic tanks, and fats and oil products are extracted using grease traps, oil traps and flotation devices. At the stage of mechanical treatment, up to three quarters of mineral contaminants are removed from waste streams. This ensures the uniformity of the liquid supply to the next processing stages.

After that, biological cleaning methods are used, carried out with the help of microorganisms and protozoa. The first structure where water enters at the biological stage is special primary sedimentation tanks, in which suspended organic matter settles. At the same time, one more type of settling tanks is used, in which activated sludge is removed from the bottom. Biological treatment removes more than 90% of organic contaminants.

At the physicochemical stage, there is a purification from dissolved impurities. This is done using special techniques and reagents. Coagulation, filtration and settling are used here. Along with them, various additional processing technologies are used, including: hyperfiltration, sorption, ion exchange, removal of nitrogen-containing substances and phosphates.

The last stage of treatment is the chlorine disinfection of the liquid from the remaining bacterial contamination. The diagram below shows in detail all the steps described with an indication of the equipment that is used in each step. It is important to note that treatment methods for different manufacturing plants differ depending on the presence of certain pollutants in the wastewater.

Features and requirements for the arrangement of treatment facilities

Household effluents are classified as uniform in composition, since the concentration of pollutants depends only on the volume of water consumed by residents. They contain insoluble impurities, emulsions, foams and suspensions, various colloidal particles, and other elements. Most of them are mineral and soluble substances. For the treatment of domestic wastewater, a basic set of treatment facilities is used, the principle of which is described above.

In general, domestic sewerage systems are considered simpler, since they are constructed to treat wastewater from one or more private houses and outbuildings. They do not have requirements for relatively high performance. For this purpose, specially designed installations are used that provide biological wastewater treatment.

Thanks to them, in suburban housing, it became possible not only to equip a shower, bathroom or toilet, but also to connect various household appliances. Usually, such installations are easy to install and operate, and do not require additional components.

For industrial effluents, the composition and the degree of pollution vary depending on the nature of the production, as well as the options for using water to support the technological process. In the production of food products, wastewater is characterized by high pollution with organic substances, therefore, the main method of treating such water is biological. The best option is to use the aerobic and anaerobic methods or a combination of both.

In other industries, the main problem is the treatment of oily and greasy effluents. For such enterprises, special oil separators or grease traps are used. But the most safe for the environment are water circulation systems for purifying polluted water. Such local cleaning systems are installed at car washes, as well as at manufacturing plants. They allow organizing a closed cycle of water use without discharging it into external water bodies.

To determine the method of organizing the treatment and the choice of a specific structure, special systems and methods are used (there are many enterprises, therefore the process must be individualized). Of no small importance is the price of equipment and work on its installation. Only specialists will help you choose the best option for each case.

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Today, the speech will once again go on a topic close to each of us, without exceptions :)

Most people, pressing the toilet button, do not think about what happens to what they flush. It has flowed and flowed, it's business. In such a big city as Moscow, a day into the sewerage system, no less than four million cubic meters of wastewater flows. This is about the same as the flow of water in the Moskva River in a day opposite the Kremlin. All this huge volume of waste water needs to be treated and this is a very difficult task.

There are two major wastewater treatment plants in Moscow, of approximately the same size. Each of them purifies half of what Moscow "produces". I've already talked about Kuryanovskaya station. Today I will tell you about the Lyubertsy station - we will go over the main stages of water purification again, but we will also touch on one very important topic - how they fight unpleasant odors at treatment plants using low-temperature plasma and waste from the perfume industry, and why this problem has become more relevant than ever ...

First, a little history. For the first time, the sewerage "came" to the area of \u200b\u200bmodern Lyubertsy at the beginning of the twentieth century. Then the Lyubertsy irrigation fields were created, on which wastewater, even according to the old technology, seeped through the ground and thereby was purified. Over time, this technology became unacceptable for the ever-increasing amount of wastewater and in 1963 a new treatment plant was built - Lyuberetskaya. A little later, another station was built - Novolyuberetskaya, actually bordering on the first and using part of its infrastructure. In fact, now it is one large cleaning station, but consisting of two parts - old and new.

Let's take a look at the map - on the left, in the west - the old part of the station, on the right, in the east - the new one:

The station area is huge, about two kilometers in a straight line from corner to corner.

As you might guess, there is a smell coming from the station. Previously, few people worried about it, but now this problem has become relevant for two main reasons:

1) When the station was built, in the 60s, almost no one lived around it. Nearby was a small village where the station workers themselves lived. Then this area was far, far from Moscow. Now there is a very active development. The station is practically surrounded by new buildings on all sides and there will be even more of them. New houses are being built even on the former sludge areas of the station (fields to which the sludge left over from wastewater treatment was transported). As a result, residents of nearby houses are forced to periodically sniff "sewer" odors, and of course they constantly complain.

2) Sewer water has become more concentrated than it used to be in Soviet times. This happened due to the fact that the volume of water used in recent years is strong decreased, while they did not go to the toilet less, but on the contrary - the population has grown. There are quite a few reasons why the "diluting" water has become much less:
a) use of meters - water has become more economical to use;
b) the use of more modern plumbing - less and less you can find a current faucet or toilet;
c) use of more economical household appliances - washing machines, dishwashers, etc .;
d) the closure of a huge number of industrial enterprises that consumed a lot of water - AZLK, ZIL, Serp and Molot (partially), etc.
As a result, if the station during construction was calculated for the volume of 800 liters of water per person per day, now in reality this figure is not more than 200. An increase in concentration and a decrease in the flow led to a number of side effects - sediment began to be deposited in sewer pipes designed for a higher flow, leading to unpleasant odors. At the station itself, it began to smell more.

To combat odors, Mosvodokanal, which is in charge of the treatment facilities, is carrying out a phased reconstruction of facilities, using several different ways to get rid of odors, which will be described below.

Let's go in order, or rather the flow of water. Waste water from Moscow enters the station through the Lyubertsy sewer canal, which is a huge underground sewer filled with waste water. The channel is self-flowing and almost throughout its entire length runs at a very shallow depth, and sometimes in general, actually above the ground. Its scale can be estimated from the roof of the administrative building of the sewage treatment plant:

The channel is about 15 meters wide (divided into three parts), and the height is 3 meters.

At the station, the channel enters the so-called receiving chamber, from where it is divided into two streams - part goes to the old part of the station, part to the new one. The receiving chamber looks like this:

The channel itself comes from the right-back, and the stream, divided into two parts, leaves through the green channels in the background, each of which can be blocked by the so-called gate - a special shutter (in the photo - dark structures). Here you can see the first innovation to combat odors. The receiving chamber is completely covered with metal sheets. Previously, it looked like a "pool" filled with fecal waters, but now they are not visible, naturally, a solid metal coating almost completely blocks the smell.

For technological purposes, only a very small hatch was left, lifting which you can enjoy the whole bouquet of smells. Hello from walsk :)

These huge dampers allow you to close the channels from the receiving chamber if necessary.

There are two channels from the receiving chamber. They, too, were recently opened, but now they are completely covered with a metal covering.

Gases from waste water accumulate under the ceiling. These are mainly methane and hydrogen sulfide - both gases are explosive at high concentrations, so the space under the ceiling must be ventilated, but then the next problem arises - if you just put a fan, then the whole point of the overlap will simply disappear - the smell will get out. Therefore, to solve the problem MKB "Gorizont" has developed and manufactured a special installation for air purification. The unit is located in a separate booth and a ventilation pipe from the channel goes to it.

This unit is an experimental one for technology development. In the near future, such installations will begin to be massively installed at treatment facilities and at sewage pumping stations, of which there are more than 150 in Moscow and from which unpleasant odors also emanate. On the right in the photo is one of the developers and testers of the installation - Alexander Pozinovsky.

The principle of operation of the installation is as follows:
polluted air is fed into four vertical stainless steel pipes from below. In the same pipes there are electrodes, to which a high voltage (tens of thousands of volts) is applied several hundred times per second, as a result of which discharges and low-temperature plasma arise. When interacting with it, most of the smelling gases turn into a liquid state and settle on the walls of the pipes. A thin layer of water constantly flows down the walls of the pipes, with which these substances mix. Water circulates in a circle, the water tank is a blue container on the right, below in the photo. The cleaned air comes out from above from stainless pipes and is simply released into the atmosphere.
For those who are more interested in more details - a photo of the stand where everything is explained.

For patriots - the unit is completely designed and created in Russia, with the exception of the power stabilizer (below in the cabinet in the photo). High-voltage part of the installation:

Since the installation is experimental, it has additional measuring equipment - a gas analyzer and an oscilloscope.

The oscilloscope shows the voltage across the capacitors. During each discharge, the capacitors are discharged and the process of their charging is clearly visible on the oscillogram.

Two tubes go to the gas analyzer - one takes air before installation, the other after. In addition, there is a tap that allows you to choose the tube that connects to the gas analyzer sensor. Alexander first shows us the "dirty" air. The content of hydrogen sulfide is 10.3 mg / m 3. After switching the tap, the content drops to almost zero: 0.0-0.1.

Each of the channels is also closed with a separate gate. Generally speaking, there are a lot of them at the station - they stick out here and there :)

After cleaning from large debris, the water enters the grit traps, which, as again, it is not difficult to guess from the name, are designed to remove small solid particles. The principle of operation of sand traps is quite simple - in fact, it is a long rectangular tank in which water moves at a certain speed, as a result, the sand simply has time to settle. Air is also supplied there, which facilitates the process. The sand is removed from the bottom using special mechanisms.

As is often the case in technology, the idea is simple, but the execution is difficult. So here too - visually it is the most "sophisticated" design on the way of water purification.

Gulls have chosen the sand traps. In general, there were a lot of gulls at the Lyubertsy station, but it was on the sand traps that there were most of them.

Enlarged the photo at home and laughed at their sight - funny birds. Lake gulls are called. No, they have a dark head not because they constantly dip it where it is not needed, just such a constructive feature :)
Soon, however, it will not be easy for them - many open water surfaces at the station will be covered.

Let's go back to the technique. The photo shows the bottom of the sand trap (not working at the moment). It is there that the sand settles and from there it is removed.

After the sand traps, water flows back into the common channel.

Here you can see what all the channels at the station looked like before they started to be covered. This channel is closing right now.

The frame is cooked from stainless steel, like most metal structures in the sewer. The fact is that the sewage system has a very aggressive environment - water is full of all sorts of substances, 100% humidity, gases that promote corrosion. Normal iron turns to dust very quickly under these conditions.

Work is underway directly above the existing channel - since this is one of the two main channels, it cannot be turned off (Muscovites will not wait :)).

In the photo there is a small difference in level, about 50 centimeters. The bottom in this place is made of a special shape to damp the horizontal water velocity. The result is very active bubbling.

After the sand traps, the water goes to the primary sedimentation tanks. In the photo - in the foreground, a chamber that receives water, from which it enters the central part of the sump in the background.

A classic sump looks like this:

And without water - like this:

Dirty water comes from the hole in the center of the sump and enters the general volume. In the sump itself, the suspension contained in the dirty water gradually settles to the bottom, along which the sludge rake is constantly moving, fixed on the farm, rotating in a circle. The scraper rakes the sediment into a special annular tray, and from it, in turn, it enters a round pit, from where it is pumped out through a pipe with special pumps. Surplus water flows into a channel laid around the sump and from there into a pipe.

Primary sedimentation tanks are another source of unpleasant odors at the plant. they contain actually dirty (purified only from solid impurities) sewage water. In order to get rid of the smell, Moskvodokanal decided to cover the sedimentation tanks, but then a big problem arose. The sump diameter is 54 meters (!). Photo with a person for scale:

Moreover, if you make a roof, then, firstly, it must withstand the snow load in winter, and secondly, it must have only one support in the center - you cannot make supports over the sump itself, because there is a constantly rotating farm. As a result, an elegant solution was made - to make the floor floating.

The ceiling is assembled from floating stainless steel blocks. Moreover, the outer ring of the blocks is fixed motionless, and the inner part rotates afloat, together with the truss.

This solution turned out to be very successful, because firstly, the problem with the snow load disappears, and secondly, the volume of air that would have to be ventilated and further purified is not formed.

According to Mosvodokanal, this design reduced odor gas emissions by 97%.

This sump was the first and experimental one where this technology was tested. The experiment was recognized as successful, and now at the Kuryanovskaya station other sedimentation tanks are already being covered in a similar way. Over time, all primary sedimentation tanks will be covered in this manner.

However, the reconstruction process is lengthy - it is impossible to turn off the entire station at once, the sedimentation tanks can only be reconstructed one after the other, turning off in turn. And a lot of money is needed. Therefore, while not all sedimentation tanks are covered, the third method of combating odors is used - the spraying of neutralizing substances.

Special sprayers were installed around the primary sedimentation tanks, which create a cloud of odor-neutralizing substances. The substances themselves smell, not to say that it is very pleasant or unpleasant, but rather specific, however, their task is not to mask the smell, but to neutralize it. Unfortunately, I did not remember the specific substances that are used, but as they said at the station, this is a waste of the French perfume industry.

For spraying, special nozzles are used that create particles with a diameter of 5-10 microns. The pressure in the pipes, if I'm not mistaken, is 6-8 atmospheres.

After the primary sedimentation tanks, water enters the aerotanks - long concrete tanks. They are supplied with a huge amount of air through pipes, and also contain activated sludge - the basis of the entire method of biological water purification. The activated sludge recycles "waste" and multiplies rapidly. The process is similar to what happens in nature in water bodies, but it proceeds many times faster due to warm water, large amounts of air and silt.

Air is supplied from the main machine room, where the turbo blowers are installed. Three turrets above the building are air intakes. The air supply process requires an enormous amount of electricity, and stopping the supply of air is disastrous. activated sludge dies very quickly, and its recovery can take months (!).

Aerotanks, oddly enough, do not particularly emit strong unpleasant odors, so it is not planned to cover them.

This photo shows how dirty water enters the aeration tank (dark) and mixes with activated sludge (brown).

Some of the structures are currently disabled and mothballed, for the reasons I wrote about at the beginning of the post - a decrease in water flow in recent years.

After aeration tanks, water enters the secondary sedimentation tanks. Structurally, they completely repeat the primary ones. Their purpose is to separate the activated sludge from the already purified water.

Conserved secondary sedimentation tanks.

Secondary sedimentation tanks do not smell - in fact, there is already clean water.

The water collected in the annular sump of the sump flows into the pipe. Part of the water undergoes additional UV disinfection and is discharged into the Pekhorka River, while part of the water goes through an underground channel to the Moskva River.

The settled activated sludge is used to obtain methane, which is then stored in semi-underground reservoirs - methane tanks and used at its own CHP.

The spent sludge is sent to sludge pads in the Moscow region, where it is additionally dehydrated and either buried or burned.

Finally, a panorama of the station from the roof of the administrative building. Click to enlarge.

I express my deep gratitude for the invitation to the press service Mosvodokanaland separately to Alexander Churbanov, director of the Lyubertsy treatment facilities. thank