City wastewater treatment plants. Journey down the funnel pipe

Urban wastewater treatment plants

1. Purpose.
Water treatment equipment is designed to clean urban Wastewater(a mixture of domestic and industrial wastewater from municipal facilities) up to the standards for discharge into a reservoir for fishing purposes.

2. Scope of application.
The productivity of treatment facilities ranges from 2,500 to 10,000 cubic meters/day, which is equivalent to the wastewater flow from a city (village) with a population of 12 to 45 thousand people.

Calculated composition and concentration of pollutants in source water:

COD – up to 300 – 350 mg/l
BODtotal – up to 250 -300 mg/l
Suspended substances – 200 -250 mg/l
Total nitrogen – up to 25 mg/l
Ammonium nitrogen – up to 15 mg/l
Phosphates – up to 6 mg/l
Petroleum products – up to 5 mg/l
Surfactant – up to 10 mg/l

Standard cleaning quality:

BODtotal – up to 3.0 mg/l
Suspended substances – up to 3.0 mg/l
Ammonium nitrogen – up to 0.39 mg/l
Nitrite nitrogen – up to 0.02 mg/l
Nitrate nitrogen – up to 9.1 mg/l
Phosphates – up to 0.2 mg/l
Petroleum products – up to 0.05 mg/l
Surfactant – up to 0.1 mg/l

3. Composition of treatment facilities.

The technological scheme for wastewater treatment includes four main blocks:

block mechanical cleaning– for removing large waste and sand;
complete biological treatment unit - to remove the main part of organic contaminants and nitrogen compounds;
deep purification and disinfection unit;
sediment processing unit.

Mechanical wastewater treatment.

To remove coarse impurities, mechanical filters are used, ensuring effective removal of contaminants larger than 2 mm in size. Sand removal is carried out in sand traps.
Removal of waste and sand is completely mechanized.

Biological treatment.

At the biological treatment stage, nitri-denitrifier aeration tanks are used, which ensures parallel removal organic matter and nitrogen compounds.
Nitridenitrification is necessary to meet discharge standards for nitrogen compounds, in particular, its oxidized forms (nitrites and nitrates).
The operating principle of this scheme is based on the recirculation of part of the sludge mixture between the aerobic and anoxic zones. In this case, the oxidation of the organic substrate, the oxidation and reduction of nitrogen compounds does not occur sequentially (as in traditional schemes), but cyclically, in small portions. As a result, nitri-denitrification processes occur almost simultaneously, which allows the removal of nitrogen compounds without the use of an additional source of organic substrate.
This scheme is implemented in aeration tanks with the organization of anoxic and aerobic zones and with the recirculation of the sludge mixture between them. Recirculation of the sludge mixture is carried out from the aerobic zone to the denitrification zone by airlifts.
In the anoxic zone of the nitri-denitrifier aeration tank, mechanical (submersible mixers) mixing of the sludge mixture is provided.

Figure 1 shows circuit diagram aeration tank of a nitri-denitrifier, when the return of the sludge mixture from the aerobic zone to the anoxic zone is carried out under hydrostatic pressure through a gravity channel, the supply of the sludge mixture from the end of the anoxic zone to the beginning of the aerobic zone is carried out by airlifts or submersible pumps.
Source wastewater and return sludge from secondary settling tanks are supplied to the dephosphatization zone (oxygen-free), where hydrolysis of high-molecular organic contaminants and ammonification of nitrogen-containing pollutants occurs. organic compounds in the absence of any oxygen.

Schematic diagram of a nitri-denitrifier aeration tank with a dephosphatization zone
I – dephosphatization zone; II – denitrification zone; III – nitrification zone, IV – sedimentation zone
1- waste water;

2- return sludge;

4- airlift;

6-silt mixture;

7- channel of circulating sludge mixture,

8- purified water.

Next, the sludge mixture enters the anoxic zone of the aeration tank, where the removal and destruction of organic contaminants, ammonification of nitrogen-containing organic contaminants by facultative microorganisms of activated sludge in the presence of bound oxygen (oxygen of nitrites and nitrates formed at the subsequent stage of purification) with simultaneous denitrification also occurs. Next, the sludge mixture is sent to the aerobic zone of the aeration tank, where the final oxidation of organic substances and nitrification of ammonium nitrogen occurs with the formation of nitrites and nitrates.

The processes occurring in this zone necessitate intensive aeration of the treated wastewater.
Part of the sludge mixture from the aerobic zone enters secondary settling tanks, and the other part returns to the anoxic zone of the aeration tank for denitrification of oxidized forms of nitrogen.
This scheme, unlike traditional ones, allows, along with effective removal nitrogen compounds to increase the efficiency of removal of phosphorus compounds. Due to the optimal alternation of aerobic and anaerobic conditions during recirculation, the ability of activated sludge to accumulate phosphorus compounds increases 5-6 times. Accordingly, the efficiency of its removal with excess sludge increases.
However, in the case of an increased content of phosphates in the source water, in order to remove phosphates to a value below 0.5-1.0 mg/l, it will be necessary to treat the purified water with an iron- or aluminum-containing reagent (for example, aluminum oxychloride). It is most advisable to introduce the reagent before the post-treatment facilities.
Wastewater clarified in secondary settling tanks is sent for additional treatment, then for disinfection and then into the reservoir.
Basic view a combined structure – a nitri-denitrifier aeration tank is shown in Fig. 2.

Post-treatment facilities.

BIOSORBER– installation for deep post-treatment of wastewater. More detailed description and common types installations.
BIOSORBER– see in the previous section.
The use of a biosorber makes it possible to obtain water purified to meet the MPC standards of a fishery reservoir.
High quality Water purification using biosorbers makes it possible to use UV installations for wastewater disinfection.

Sludge treatment facilities.

Considering the significant volume of sediments generated during wastewater treatment (up to 1200 cubic meters/day), to reduce their volume it is necessary to use structures that ensure their stabilization, compaction and mechanical dewatering.
For aerobic stabilization of sediments, structures similar to aeration tanks with a built-in sludge compactor are used. Similar technological solution allows you to eliminate subsequent decay of the resulting sediments, as well as approximately halve their volume.
A further reduction in volume occurs at the stage of mechanical dewatering, which involves preliminary thickening of the sludge, its treatment with reagents, and then dewatering on filter presses. The volume of dewatered sludge for a station with a capacity of 7000 cubic meters per day will be approximately 5-10 cubic meters per day.
Stabilized and dewatered sludge is sent for storage on sludge beds. The area of the sludge beds in this case will be approximately 2000 sq.m (the capacity of the treatment facilities is 7000 cubic meters/day).

4. Structural design of treatment facilities.

Structurally, treatment facilities for mechanical and complete biological treatment are made in the form of combined structures based on oil tanks with a diameter of 22 and a height of 11 m, covered with a roof on top and equipped with ventilation, internal lighting and heating systems (coolant consumption is minimal, since the main volume of the structure is occupied by source water, which has temperature within the range of not lower than 12-16 degrees).
The productivity of one such structure is 2500 cubic meters per day.
The aerobic stabilizer with a built-in sludge compactor is designed in a similar way. The diameter of the aerobic stabilizer is 16 m for stations with a capacity of up to 7.5 thousand cubic meters per day and 22 m for a station with a capacity of 10 thousand cubic meters per day.
To place a post-treatment stage - on the basis of installations BIOSORBER BSD 0.6, disinfection installations for treated wastewater, an air-blowing station, a laboratory, household and utility rooms require a building 18 m wide, 12 m high and long for a station with a capacity of 2500 cubic meters per day - 12 m, 5000 cubic meters per day - 18, 7500 - 24 and 10,000 cubic meters/day – 30 m.

Specification of buildings and structures:

combined structures – nitri-denitrifier aeration tanks with a diameter of 22 m – 4 pcs.;
production and utility building 18x30 m with a post-treatment unit, blower station, laboratory and utility rooms;
combined structure aerobic stabilizer with built-in sludge compactor with a diameter of 22 m - 1 pc.;
gallery 12 m wide;
sludge beds 5 thousand sq.m.

The Village continues to explain how the things that citizens use every day work. In this issue - the sewerage system. After we press the flush button on the toilet, turn off the tap and go about our business, tap water turns into waste water and begins its journey. To get back into the Moscow River, she needs to walk kilometers sewer networks and several stages of cleaning. The Village learned how this happens after visiting the city's wastewater treatment plants.

Through the pipes

At the very beginning, water enters internal pipes houses with a diameter of only 50–100 millimeters. Then it goes along the network a little wider - the courtyards, and from there - to the street ones. At the border of each yard network and at the point where it transitions to the street network, an inspection well is installed, through which you can monitor the operation of the network and clean it if necessary.

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

Basically, due to the depth and natural topography of the territory, water flows through the pipes on its own, but in some places pumping stations are required, there are 156 of them in Moscow.

Wastewater goes to one of four treatment plants. The cleaning process is continuous, and peaks in hydraulic load occur at 12 noon and 12 noon. The Kuryanovsky treatment plant, which is located near Maryin and is considered one of the largest in Europe, receives water from the southern, southeastern and southwestern parts of the city. Sewage from the northern and eastern parts of the city goes to the treatment plant in Lyubertsy.

Treatment

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

Previously, this place was called an aeration station; it was launched in December 1950. Now the treatment plant is 66 years old, and Vadim Gelievich Isakov worked here for 36 of them. 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 foul-smelling wastewater arrives at the treatment plant warm. Even in the coldest time of the year, its temperature does not drop below plus 18 degrees. Wastewater is met by a receiving and distribution chamber. But we won’t see what’s happening there: the chamber was completely closed so that the smell wouldn’t spread. By the way, the smell of the huge (almost 160 hectares) wastewater treatment area is quite tolerable.

After this, the mechanical cleaning stage begins. Here, special grates trap debris that floats along with the water. Most often these are rags, paper, personal hygiene products (wipes, diapers), and also food waste - for example, potato peelings and chicken bones. “You won’t meet anything. It happened that bones and skins arrived from meat processing plants,” they say with a shudder at the treatment plants. The only pleasant thing was gold jewelry, although we did not find any eyewitnesses of such a catch. Seeing the debris-retaining grate is the most terrifying part of the excursion. In addition to all sorts of nasty things, there are many, many lemon slices stuck in it: “You can guess the time of year by the contents,” the employees note.

A lot of sand comes with wastewater, and to prevent it from settling on structures and clogging pipelines, it is removed in sand traps. Sand in liquid form is supplied to a special area, where it is washed with industrial water and becomes ordinary, that is, suitable for landscaping. Treatment plants use sand for their own needs.

The stage of mechanical cleaning in the primary settling tanks is completed. These are large tanks in which fine suspended matter is removed from the water. The water comes here cloudy and leaves cleared.

Biological treatment

Biological treatment begins. It occurs in structures called aeration tanks. They artificially support the vital activity of a community of microorganisms called activated sludge. Organic contaminants in water are the most desirable food for microorganisms. Air is supplied to the aeration tanks, which prevents the sludge from settling so that it comes into contact with wastewater as much as possible. This continues for eight to ten hours. “Similar processes occur in any natural body of water. The concentration of microorganisms there is hundreds of times lower than what we create. IN natural conditions it would have lasted weeks and months,” says Isakov.

An aeration tank is a rectangular tank divided into sections in which waste water snakes. “If you look through a microscope, everything there is crawling, moving, moving, swimming. We force them to 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 secondary settling tanks. There, the sludge settles to the bottom and is collected by suction pumps, after which 90% is returned to the aeration tanks for a continuous cleaning process, and 10% is considered excess and is disposed of.

Return to the river

Biologically purified water undergoes tertiary treatment. To check, it is filtered through a very fine sieve, and then discharged into the station’s outlet channel, on which there is an ultraviolet disinfection unit. Ultraviolet disinfection is the fourth and final stage cleaning. At the station, the water is divided into 17 channels, each of which is illuminated by a lamp: the water in this place acquires an acidic tint. This is a modern and largest such block in the world. Although according to the old project it was not available, previously they wanted to disinfect the water with liquid chlorine. “It’s good that it didn’t come to that. We would destroy every living thing in the Moscow River. The reservoir would be sterile, but dead,” says Vadim Gelievich.

In parallel with water purification, the station deals with sediment. Sludge from primary settling tanks and excess activated sludge are processed together. They enter 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 release unpleasant odor. This sludge is then pumped to dewatering complexes outside the Moscow Ring Road. “30–40 years ago, sediment was dried on sludge beds under natural conditions. This process lasted from three to five years, but now dehydration is instantaneous. The sediment itself is valuable. mineral fertilizer, V Soviet times he was popular, state farms took him with pleasure. But now no one needs it, and the station pays up to 30% of the total cleaning costs for disposal,” says Vadim Gelievich.

A third of the sludge breaks down into water and biogas, saving on disposal costs. Part of the biogas is burned in the boiler room, 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 plants relative energy independence.

Fish in the sewer

Previously, on the territory of the Kuryanovsky treatment plant there was an engineering center with its own production base. Employees carried out unusual experiments, for example, breeding sterlet and carp. Some of the fish lived in tap water, and part of it is in the sewer, which has been cleaned. Nowadays, fish are found only in the discharge canal; there are even signs saying “Fishing is prohibited.”

After all the purification processes, the water flows through the discharge canal - a small river 650 meters long - into the Moscow River. Here and wherever the process goes under open air, there are many seagulls swimming on the water. “They don’t interfere with the processes, but they spoil the aesthetic appearance“Isakov is sure.

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

The volume of treated wastewater is equal to approximately a third of all water in the Moscow River above the discharge. If treatment plants failed, downstream communities would be on the brink environmental disaster. But this is practically impossible.

Sewage treatment facilities OS, WWTP, BOS.

One of the main methods of protection natural environment Anti-pollution is the prevention of untreated water and other harmful components from entering water bodies. Modern treatment facilities are a set of engineering and technical solutions for the consistent filtration and disinfection of contaminated wastewater for the purpose of its reuse in production or for discharge into natural reservoirs. For this purpose, a number of methods and technologies have been developed, which will be discussed below.

Main cleaning steps

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

In a sand trap, small particles of sand, slag and other similar mineral elements are deposited under the influence of gravity. At the same time, the filtered composition is suitable for further use after processing. The remaining undissolved substances are reliably retained in special settling tanks and septic tanks, and fats and petroleum products are extracted using grease traps, oil traps and flotators. At the mechanical treatment stage, up to three-quarters of mineral contaminants are removed from waste streams. This ensures uniform supply of liquid to the next stages of processing.

After this, biological cleaning methods are used, performed with the help of microorganisms and protozoa. The first structure where water enters at the biological stage is special primary settling tanks, in which suspended organic matter settles. At the same time, another type of settling tank is used, in which activated sludge is removed from the bottom. Biological treatment allows you to remove more than 90% of organic contaminants.

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

The last stage of treatment is considered to be chlorine disinfection of the liquid from remaining bacterial contaminants. The diagram below shows in detail all the stages described, indicating the equipment that is used in each stage. It is important to note that treatment methods vary from plant to plant depending on the presence of certain contaminants in the wastewater.

Features and requirements for the arrangement of treatment facilities

Domestic wastewater is classified as monotonous in composition, since the concentration of pollutants depends only on the volume of water consumed by residents. They contain insoluble contaminants, emulsions, foams and suspensions, various colloidal particles, as well as other elements. The main part of them are mineral and soluble substances. To treat domestic wastewater, a basic set of treatment facilities is used, the operating principle of which is described above.

Generally domestic sewerage are considered simpler, since they are constructed to treat wastewater from one or more private houses and outbuildings. They are not subject to high performance requirements. For this purpose, specially designed installations are used that provide biological treatment of wastewater.

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

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

In other industries, the main problem is the treatment of oil and grease-containing wastewater. For such enterprises, special oil separators or grease traps are used. But water circulation systems for purifying contaminated water are considered the safest for the environment. Such local treatment complexes are installed at car washes, as well as at manufacturing enterprises. They allow you to organize a closed cycle of water use without discharging it into external bodies of water.

To determine the method of organizing cleaning and selecting a specific facility, special systems and methods are used (there are many enterprises, so the process must be individualized). The price of equipment and installation work is of no small importance. The best option Only specialists will help you choose for each case.

Submit your application* Get a consultation

→ Solutions for wastewater treatment plant complexes

Examples of wastewater treatment plants in major cities

Before you consider specific examples treatment facilities, it is necessary to determine what the terms largest, large, medium and small city mean.

With a certain degree of convention, cities can be classified by the number of inhabitants or, taking into account professional specialization, by the amount of wastewater entering treatment plants. So for the largest cities with a population of more than 1 million people, the amount of wastewater exceeds 0.4 million m3/day, for major cities with a population of 100 thousand to 1 million people, the amount of wastewater is 25-400 thousand m3/day. Medium-sized cities have a population of 50-100 thousand people, and the amount of wastewater is 10-25 thousand m3/day. In small towns and urban-type settlements, the number of inhabitants ranges from 3-50 thousand people (with a possible gradation of 3-10 thousand people; 10-20 thousand people; 25-50 thousand people). At the same time, the estimated amount of wastewater varies in a fairly wide range: from 0.5 to 10-15 thousand m3/day.

The share of small towns in the Russian Federation is 90% of total number cities. It is also necessary to take into account that the drainage system in cities can be decentralized and have several treatment facilities.

Let's look at the most illustrative examples of large wastewater treatment plants in the cities of the Russian Federation: Moscow, St. Petersburg and Nizhny Novgorod.

Kuryanovskaya aeration station (KSA), Moscow. The Kuryanovskaya aeration station is the oldest and largest aeration station in Russia; using its example, one can quite clearly study the history of the development of wastewater treatment equipment and technology in our country.

The area occupied by the station is 380 hectares; design capacity – 3.125 million m3 per day; of which almost 2/3 is domestic and 1/3 is industrial wastewater. The station has four independent block structures.

The development of the Kuryanovskaya aeration station began in 1950 after the commissioning of a complex of structures with a throughput capacity of 250 thousand m3 per day. An industrial experimental technological and design base was laid on this block, which became the basis for the development of almost all aeration stations in the country, and was also used in the expansion of the Kuryanovskaya station itself.

In Fig. 19.3 and 19.4 show technological schemes for wastewater treatment and sludge treatment at the Kuryanovskaya aeration station.

Wastewater treatment technology includes the following main structures: grates, sand traps, primary settling tanks, aeration tanks, secondary settling tanks, wastewater disinfection facilities. Some biologically treated wastewater undergoes post-treatment using granular filters.

Rice. 19.3. Technological scheme for wastewater treatment at the Kuryanovskaya aeration station:
1 – grid; 2 – sand trap; 3 – primary settling tank; 4 – aeration tank; 5 – secondary settling tank; 6 – flat slot sieve; 7 – fast filter; 8 – regenerator; 9 – main machine building of the central processing plant; 10 – sludge compactor; 11 – gravity belt thickener; 12 – unit for preparing a flocculant solution; 13 – industrial water pipeline structures; 14 – sand processing shop; 75 – incoming waste water; 16 - rinsing water from quick filters; 17 – sand pulp; 18 – water from the sand shop; 19 – floating substances; 20 – air; 21 – sediment from primary settling tanks for sludge treatment facilities; 22 - circulating activated sludge; 23 – filtrate; 24 – disinfected process water; 25 – process water; 26 – air; 27 – condensed activated sludge for sludge treatment facilities; 28 – disinfected industrial water to the city; 29 – purified water in the river. Moscow; 30 – post-purified wastewater in the river. Moscow

The KSA is equipped with mechanized gratings with 6 mm openings and continuously moving scraper mechanisms.

Three types of sand traps are used at KSA: vertical, horizontal and aerated. After dewatering and processing in a special workshop, sand can be used in road construction and for other purposes.

Radial-type sedimentation tanks with diameters of 33, 40 and 54 m are used as primary settling tanks at KSA. The design duration of settling is 2 hours. Primary settling tanks in the central part have built-in pre-aerators.

Biological wastewater treatment is carried out in four-corridor aeration tanks-displacers, the percentage of regeneration ranges from 25 to 50%.

Air for aeration is supplied to the aeration tanks through filter plates. Currently, to select the optimal aeration system, tubular polyethylene aerators from Ecopolymer and disc aerators from Green-Frog and Patfil are being tested in a number of sections of aeration tanks.

Rice. 19.4. Technological scheme for processing sludge at the Kuryanovskaya aeration station:
1 – loading chamber of the digester; 2 – digester; 3 – unloading chamber of digesters; 4 – gas tank; 5 – heat exchanger; 6 – mixing chamber; 7 – washing tank; 8 – compactor of fermented sludge; 9 – filter press; 10 – unit for preparing a flocculant solution; 11 – sludge platform; 12 – sediment from primary settling tanks; 13 – excess activated sludge; 14 – gas for spark plug; 15 – fermentation gas into the boiler room of the aeration station; 16 – process water; 17 – sand on sand pads; 18 – air; 19 – filtrate; 20 - drain water; 21 – sludge water into the city sewerage system

One of the sections of the aeration tanks has been reconstructed to operate using a single-sludge nitride-denitrification system, which also includes a phosphate removal system.

Secondary settling tanks, like the primary ones, are of the radial type, with diameters of 33, 40 and 54 m.

About 30% of biologically treated wastewater is subjected to additional treatment, which is first treated on flat slotted sieves and then on granular filters.

For sludge digestion at KSA, buried digester tanks with a diameter of 24 m are used from monolithic reinforced concrete with earth filling, above ground with a diameter of 18 m with thermal insulation of the walls. All digesters operate according to a flow-through scheme, in thermophilic mode. The released gas is discharged to the local boiler room. After the digesters, the digested mixture of raw sludge and excess activated sludge undergoes compaction. From total number 40-45% of the mixture is sent to the sludge beds, and 55-60% is sent to the mechanical dewatering workshop. The total area of the sludge beds is 380 hectares.

Mechanical dewatering of sludge is carried out using eight filter presses.

Lyubertsy aeration station (LbSA), Moscow. More than 40% of wastewater in Moscow and large cities of the Moscow region is treated at the Lyubertsy aeration station (LbSA), located in the village of Nekrasovka, Moscow region (Fig. 19.5).

LbSA was built in the pre-war years. The technological process of treatment consisted of mechanical treatment of wastewater and subsequent treatment in irrigation fields. In 1959, by decision of the government, construction of an aeration station began on the site of the Lyubertsy irrigation fields.

Rice. 19.5. Plan of treatment facilities for Lyubertsy and Novolubertsy aeration stations:
1 – supply of wastewater to LbSA; 2 – supply of wastewater to NLbSA; 3 – LbSA; 4 – NLbSA; 5 – sediment treatment facilities; b – discharges of treated wastewater

The technological scheme for wastewater treatment at LbSA is practically no different from the accepted scheme at KSA and includes the following structures: grates; sand traps; primary settling tanks with pre-aerators; aeration tanks-displacers; secondary settling tanks; facilities for sludge treatment and wastewater disinfection (Fig. 19.6).

Unlike KSA structures, most of which were built from monolithic reinforced concrete, prefabricated reinforced concrete structures were widely used at LbSA.

After the construction and commissioning of the first unit in 1984, and subsequently the second unit of the treatment facilities of the Novolubertsy aeration station (NLbSA), the design throughput LbSA is 3.125 million m3/day. The technological scheme for wastewater treatment and sludge treatment at LbSA is practically no different from the classical scheme adopted at KSA.

However, in last years at Lyubertsy station they conduct great work on modernization and reconstruction of wastewater treatment facilities.

New foreign and domestic fine-clearance mechanized gratings (4-6 mm) were installed at the station, and the existing mechanized gratings were modernized using the technology developed at the Mosvodokanal MGP with a reduction in the size of the gaps to 4-5 mm.

Rice. 19.6. Technological scheme for wastewater treatment of the Lyubertsy aeration station:
1 – waste water; 2 – gratings; 3 – sand traps; 4 – pre-aerators; 5 – primary settling tanks; 6 – air; 7 – aeration tanks; 8 – secondary settling tanks; 9 – sludge compactors; 10 – filter presses; 11 – dewatered sludge storage areas; 12 – reagent facilities; 13 – compactors of fermented sludge in front of filter presses; 14 – sediment preparation unit; 15 – digesters; 16 – sand bunker; 17 – sand classifier; 18 – hydrocyclone; 19 – gas tank; 20 – boiler room; 21 – hydraulic presses for waste dewatering; 22 – emergency release

The greatest interest is generated by the technological scheme of block II of NLbSa, which is a modern single-silt nit-ri-denitrification scheme with two stages of nitrification. Along with the deep oxidation of carbon-containing organic substances, a deeper process of oxidation of nitrogen of ammonium salts occurs with the formation of nitrates and a decrease in phosphates. The introduction of this technology will make it possible in the near future to obtain purified wastewater at the Lyubertsy aeration station that would meet modern standards. regulatory requirements for discharge into fishery reservoirs (Fig. 19.7). For the first time, about 1 million m3/day of wastewater at LbSA is subjected to deep biological treatment with the removal of nutrients from treated wastewater.

Almost all raw sludge from primary settling tanks undergoes pre-treatment on screens before digestion in digesters. Main technological processes sewage sludge treatment at LbSA are: gravitational compaction of excess activated sludge and raw sludge; thermophilic fermentation; washing and compaction of fermented sludge; polymer conditioning; mechanical neutralization; deposit; natural drying (emergency sludge areas).

Rice. 19.7. Technological scheme for wastewater treatment at LbSA using a single-silt nitri-denitrification scheme:
1 – initial wastewater; 2 – primary settling tank; 3 – clarified waste water; 4 – aeration tank-denitrifier; 5 – air; 6 – secondary settling tank; 7 – purified waste water; 8 – recirculating activated sludge; 9 – raw sediment

To dewater the sludge, new frame filter presses have been installed, making it possible to obtain cake with a moisture content of 70-75%.

Central aeration station, St. Petersburg. The treatment facilities of the Central Aeration Station of St. Petersburg are located at the mouth of the river. Neva on the artificially reclaimed Bely Island. The station was put into operation in 1978; the design capacity of 1.5 million m per day was achieved in 1985. The development area is 57 hectares.

The central aeration station of St. Petersburg receives and processes about 60% of the city's domestic and 40% of industrial wastewater. St. Petersburg is the largest city in the Baltic Sea basin, which places a special responsibility on ensuring its environmental safety.

The technological scheme of wastewater treatment and sludge treatment of the Central Aeration Station of St. Petersburg is presented in Fig. 19.8.

The maximum flow rate of wastewater pumped by the pumping station in dry weather is 20 m3/s and in rainy weather – 30 m/s. Wastewater coming from the inlet collector of the city drainage network is pumped into the receiving chamber for mechanical treatment.

The mechanical cleaning facilities include: a receiving chamber, a screen building, primary settling tanks with grease collectors. Initially, wastewater is treated on 14 mechanized rake and step screens. After the screens, wastewater enters sand traps (12 pcs.) and then through a distribution channel is discharged to three groups of primary settling tanks. Primary settling tanks of radial type, 12 pieces. The diameter of each settling tank is 54 m with a depth of 5 m.

Rice. 19.8. Technological scheme for wastewater treatment and sludge treatment of the Central Station of St. Petersburg:
1 – wastewater from the city; 2 – main pumping station; 3 – supply channel; 4 – mechanized gratings; 5 – sand traps; 6 – waste; 7 – sand; 8 – sand; sites; 9 – primary settling tanks; 10 – wet sediment reservoir; 11 – aeration tanks; 12 – air; 13 – superchargers; 14 – return activated sludge; 15 – sludge pumping station; 16 – secondary settling tanks; 17 – release chamber; 18 – Neva River; 19 – activated sludge; 20 – sludge compactors; 21 – receiving tank;
22 – centripresses; 23 – cake for combustion; 24 – combustion of sludge; 25 – oven; 26 – ash; 27 – flocculant; 28 – drain water from sludge compactors; 29 – water; 30 – solution
flocculant; 31 – centrifuge

The biological treatment facilities include aeration tanks, radial settling tanks and the main machine building, which includes a block of blowing units and sludge pumps. The aeration tanks consist of two groups, each of which consists of six parallel three-corridor aeration tanks 192 m long with a common upper and lower channel, the width and depth of the corridors are 8 and 5.5 m, respectively. Air is supplied to the aeration tanks through fine-bubble aerators. Regeneration of activated sludge is 33%, while return activated sludge from secondary settling tanks is supplied to one of the aeration tank corridors, which serves as a regenerator.

From the aeration tanks, purified water is sent to 12 secondary settling tanks to separate activated sludge from biologically treated wastewater. Secondary settling tanks, like the primary ones, are of a radial type with a diameter of 54 m and a settling zone depth of 5 m. From the secondary settling tanks, activated sludge flows under hydrostatic pressure into the sludge pumping station. After secondary settling tanks, purified water is discharged into the river through the outlet chamber. Neva.

In the mechanical sludge dewatering shop, raw sludge from primary settling tanks and compacted activated sludge from secondary settling tanks are processed. The main equipment of this workshop is ten centripresses equipped with preheating systems for a mixture of raw sludge and activated sludge. To increase the degree of moisture transfer of the mixture, a flocculant solution is supplied to the centripresses. After processing in centripresses, the cake moisture reaches 76.5%.

The sludge incineration shop has 4 fluidized bed furnaces (French company OTV).

Distinctive feature of these treatment facilities is that in the sludge treatment cycle there is no preliminary digestion in digesters. Dewatering of a mixture of sediments and excess activated sludge occurs directly in centripresses. The combination of centripresses and combustion of compacted sediments dramatically reduces the volume of the final product - ash. Compared to traditional mechanical sludge treatment, the resulting ash is 10 times less than dewatered cake. Using a method of burning a mixture of sludge and excess activated sludge in fluidized bed kilns guarantees sanitary safety.

Aeration station in Nizhny Novgorod. Nizhny Novgorod aeration station is a complex of structures designed for complete biological treatment of domestic and industrial wastewater in Nizhny Novgorod and Bor. The technological scheme includes the following structures: mechanical cleaning unit - grates, sand traps, primary settling tanks; biological treatment unit – aeration tanks and secondary settling tanks; post-treatment; sediment treatment facilities (Fig. 19.9).

Rice. 19.9. Technological scheme for wastewater treatment at the Nizhny Novgorod aeration station:
1 – wastewater receiving chamber; 2 – gratings; 3 – sand traps; 4 – sand areas; 5 – primary settling tanks; 6 – aeration tanks; 7 – secondary settling tanks; 8 – pumping station for excess activated sludge; 9 – airlift chamber; 10 – biological ponds; 11 – contact tanks; 12 – release in the river. Volga; 13 – sludge compactors; 14 – pumping station for raw sludge (from primary settling tanks); 75 – digesters; 16 – sludge pumping station; 17 - flocculant; 18 – filter press; 19 – sludge platforms

The design capacity of the structures is 1.2 million m3/day. The building has 4 mechanized screens with a capacity of 400 thousand m3/day each. Waste from the grates is transported using conveyors, dumped into bins, chlorinated and taken to a composting site.

Sand traps include two blocks: the first consists of 7 horizontal aerated sand traps with a capacity of 600 m3/h each, the second - of 2 horizontal slotted sand traps with a capacity of 600 m3/h each.

8 primary radial settling tanks with a diameter of 54 m were built at the station. To remove floating contaminants, the settling tanks are equipped with grease collectors.
4-corridor aeration tanks-mixers are used as biological treatment facilities. The dispersed inlet of wastewater into aeration tanks makes it possible to change the volume of regenerators from 25 to 50%, ensuring good mixing incoming water with activated sludge and uniform oxygen consumption along the entire length of the corridors. The length of each aeration tank is 120 m, the total width is 36 m, and the depth is 5.2 m.

The design of secondary settling tanks and their dimensions are similar to the primary ones; a total of 10 secondary settling tanks were built at the station.

After secondary settling tanks, the water is sent for further treatment to two biological ponds with natural aeration. Biological ponds are built on natural basis and embanked with earthen dams; The water surface area of each pond is 20 hectares. The residence time in biological ponds is 18-20 hours.

After bioponds, purified wastewater is disinfected in contact tanks using chlorine.

Purified and disinfected water enters the drainage channels through the Parshal trays and, after being saturated with oxygen in the spillway differential device, enters the river. Volga.

A mixture of raw sludge from primary settling tanks and compacted excess activated sludge is sent to digesters. The thermophilic regime is maintained in digesters.

The digested sludge is partly fed to sludge beds and partly to a belt filter press.

Every Russian city has a system of special structures that are designed to purify wastewater containing a wide variety of mineral and organic compounds to a state in which it is possible to discharge them into environment without harming the environment. Modern treatment facilities for the city, which are developed and manufactured by the Flotenk company, are quite technically complex complexes, consisting of several separate blocks, each of which performs a strictly defined function.

To order and calculate treatment facilities, send a request to E-mail: or call toll-free 8 800 700-48-87 Or fill out the questionnaire:

Storm sewer	.doc	1.31 MB	Download
Large household services (villages, hotels, kindergartens, etc.)	.xls	1.22 MB	Fill out online
Industrial waste	.doc	1.30 MB	Download Fill out online
Car wash system	.doc	1.34 MB	Download Fill out online
Grease separator	.doc	1.36 MB	Fill out online
UV disinfectant	.doc	1.37 MB	Fill out online
	.pdf	181.1 KB	Download

KNS:

Advantages of municipal wastewater treatment plants produced by Flotenk

The development, production and installation of treatment facilities is one of the main specializations of the Flotenk company. Its systems, as practice shows, have many advantages over similar products produced by many other domestic and foreign companies. Among them, it is worth noting the high efficiency of urban wastewater treatment plants from Flotenk, which is due to a carefully calculated, well-thought-out and perfectly implemented design. In addition, they are characterized by increased reliability and long service life, since their main components are made of fiberglass that is durable and resistant to various types of adverse effects.

How is city wastewater treated?

The city's wastewater is treated in stages. Effluents coming through sewer system to treatment plants, first of all they enter a block where the mechanical impurities contained in them are separated. After this, the wastewater goes to biological treatment, during which most of the organic compounds, as well as nitrogen compounds, are removed from it. In the next, third block, wastewater is further purified, as well as its disinfection either with chlorine or by treatment ultraviolet radiation. Once in the last block, municipal wastewater settles and produces sediment, which is subject to further processing.

The treatment facilities, which are developed and manufactured by the Flotenk company for cities, have mechanical wastewater treatment units, in which specialized meshes are installed in very large cells to remove sufficiently large waste. small sizes. In addition, these blocks are also equipped with sand traps. They are containers of sufficiently large volume, in which sand settles out due to a sharp decrease in the speed of wastewater flow under the influence of gravity. These tanks are manufactured at Flotenk's own production facilities and have several components and are assembled directly at the installation site.

Biological treatment of municipal wastewater is also carried out in special tanks called aeration tanks. In them, a component such as activated sludge is added to the wastewater, which contains microorganisms that decompose various substances of organic origin. In order for the biological treatment process to proceed faster, air is pumped into the aeration tanks using compressors.

Secondary settling tanks, into which wastewater is sent after biological treatment, are necessary in order to separate the activated sludge contained in them, which is then sent back to aeration tanks. In addition, wastewater is disinfected in these containers, which, at the end of this process, is sent to discharge points (most often these are open reservoirs).