Before considering specific examples of wastewater treatment plants, it is necessary to define what the terms “largest, large, medium and small city” mean.

For the largest cities with a population of more than 1 million people. the amount of wastewater exceeds 0.4 million m 3 / day, for large cities with a population of 100 thousand to 1 million people. the amount of wastewater is 25-400 thousand m 3 /day. 50-100 thousand people live in medium-sized cities, and the amount of wastewater is Yu-25 thousand m 3 / day. In small towns and urban-type settlements, the number of inhabitants is from 3 to 50 thousand people. (with a possible gradation of 3-10 thousand people; Yu-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 m 3 /day.

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

Let's consider the most significant examples of large treatment facilities in the cities of the Russian Federation: Moscow, St. Petersburg, Novgorod.

Kuryanovskaya aeration station (KSA), Moscow - the oldest and largest aeration station in Russia, using its example, you can clearly study the history of the development of equipment and technology for wastewater treatment in our country. The area occupied by the station is 380 ha; design capacity - 3.125 million m 3 / day, of which almost 2 / s are domestic and "/ 3 - industrial wastewater. The station has four independent blocks of structures.

On fig. 17.3 and 17.4 show technological schemes for wastewater treatment and sludge treatment of the Kuryanovskaya aeration station.

Wastewater treatment technology includes the following main facilities: gratings, sand traps, primary settling tanks, aeration tanks, secondary settling tanks, wastewater disinfection facilities. Part of the biologically treated wastewater undergoes post-treatment on granular filters.

Mechanized gratings with 6 mm gaps are installed on the KSA. Three types of sand traps are operated at the station - ver-

Rice. 17.3.

• 1 - lattice; 2 - sand trap; 3 - primary sump; 4 - aeration tank;
• 5 - secondary sump; 6 - flat slotted sieve; 7 - quick filter;
• 8 - regenerator; 9 - the main engine building of the CBO; 10 - sludge thickener; 11 - gravity belt thickener; 1 2 - flocculant solution preparation unit; 13 - industrial water pipeline structures; 14 - sand processing shop;
• 15 - incoming waste water; 16 - wash water from quick filters;
• 17 - sand pulp; 18 - water from the sand shop; 19 - floating substances; 20 - air; 21 - sludge from primary settling tanks for sludge treatment facilities; 22 - circulating activated sludge; 23 - filtrate; 24 - disinfected process water; 25 - industrial 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 - additionally treated wastewater in the river. Moscow

tical, horizontal and aerated. As primary settling tanks, radial type settling tanks with a diameter of 33, 40 and 54 m are used. The design duration of settling is 2 hours. Primary settling tanks in the central part have built-in preaerators.

Biological wastewater treatment is carried out in four-corridor displacer aerotanks, the percentage of regeneration is from 25 to 50%. Air for aeration is supplied to the aerotanks through filter plates; in a number of sections of the aerotanks, tubular polyethylene aerators from the Ecopolymer company, plate aerators from the Greenfrog and Patfil companies are installed. One of the sections of the aeration tanks was reconstructed to operate on a single-silt nitride-denitrification system, which also includes a phosphate removal system.

Secondary settling tanks, as well as primary ones, are of the radial type with a diameter of 33, 40 and 54 m. About 30% of biologically treated wastewater undergoes post-treatment.

Rice. 17.4.

• 1 - loading chamber of the digester; 2 - digester; 3 - unloading chamber of digesters; 4 - gas holder; 5 - heat exchanger; 6 - mixing chamber;
• 7 - washing tank; 8 - digested sludge compactor; 9 - filter press; 10 - flocculant solution preparation unit; 11 - silt platform; 12 - sludge from primary settling tanks; 13 - excess activated sludge; 14 - gas per candle; 15 - fermentation gas in the boiler room of the aeration station; 16 - technical water; 17 - sand on sand platforms; 18 - air; 1 9 - filtrate;
• 20 - drain water; 21 - silt water to the city sewer

For sludge digestion at KSA, digesters operating in thermophilic mode are used, made of monolithic reinforced concrete with earthen sprinkling and ground-based ones with a diameter of 18 m with thermal insulation of walls. The escaping gas is diverted to the local boiler house. After fermentation, 40-45% is sent to sludge sites, and 55-60% - to the mechanical dehydration shop. Mechanical dehydration of sediments is carried out on filter presses.

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

Lyubertsy irrigation fields were built in the pre-war years. In 1959, construction of the LbSA began here. The technological scheme of wastewater treatment at LbSA practically does not differ from the adopted scheme at KSA and includes the following facilities: screens, sand traps, primary settling tanks with preaerators, displacing aerotanks, secondary settling tanks, facilities for sludge treatment and wastewater disinfection. In 1984, the first and then the second block of structures of the Novovolyuberetsk aeration station (NLbSA) were built; at present, the throughput capacity of the LbSA is 3.125 million m 3 /day.

New foreign and domestic small-gauge mechanized gratings (4-6 mm) were installed at the station. For the first time, at the second block of the NLbSa, a modern single-silt nitrification-denitrification scheme with two nitrification stages was used, where about 1 million m 3 / day of wastewater is subjected to deep biological treatment with the removal of nutrients from treated wastewater.

The main technological processes for the treatment of sewage sludge at LbSA are: gravity compaction of excess activated sludge and wet sludge; thermophilic fermentation; washing and compaction of digested sludge; polymer conditioning; mechanical neutralization on frame filter presses; deposit; natural drying (emergency silt pads).

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 3 /day was reached in 1985. The building area is 57 hectares.

The technological scheme of wastewater treatment and sludge treatment of the Central Aeration Station of St. Petersburg is shown in fig. 17.5.

The structure of mechanical treatment facilities includes: a receiving chamber, a building of mechanized grates, sand traps, primary settling tanks with a diameter of 54 m, aeration tanks with a length of 192 m. Air is supplied to the aeration tanks through fine-bubble aerators. Regeneration of activated sludge is 33%. After the secondary settling tanks, the treated wastewater is discharged through the outlet chamber into the river. Neva. Mechanical dehydration of sediments and activated sludge is carried out on centrifuges. Fluidized bed furnaces are installed in the sludge incineration shop.

Rice. 17.5.

• 1 - main pumping station; 2 - receiving chamber; 3 - mechanized gratings; 4 - horizontal aerated sand traps; 5 - radial primary settling tanks; 6 - three-corridor aerotanks; 7 - radial secondary clarifiers; 8 - release chamber; 9 - pumping station of the sludge treatment shop; 10 - sludge treatment shop; 11 - sludge thickeners; 12 - compacted sludge pumping station; 13 - sand platforms; 14 - pavilion of mine chambers;
• 15 - block of the pumping and air blowing station; 16 - reservoir of active sludge;
• -- waste water; ----- activated sludge; - sediment;
• -------compacted sludge

Examples of wastewater treatment plants

Stations with a capacity of 70-280 thousand m 3 / day. TsNIIEP of engineering equipment has developed standard stations for biological wastewater treatment with a capacity of 25-280 thousand m 3 /day. The structures are designed in a combined version (blocks of primary settling tanks, blocks of aerotanks and secondary settling tanks - with horizontal and radial settling tanks) or in the form of separately located tanks (radial round settling tanks). All structures are made of precast concrete elements. The general layout of the station with a capacity of 70-100 thousand m 3 /day with horizontal settling tanks is shown in fig. 17.6.

Disinfection of waste liquid is provided by liquid chlorine. Sludge treatment is adopted with aerobic digestion, centrifugation and composting. Options are possible: with digestion in digesters and mechanical dehydration; with thermal drying by the method of oncoming gas jets and subsequent drying on sludge beds.

As part of the complex of treatment facilities, production and production-auxiliary buildings are being designed.

Stations with a capacity of 25-70 thousand m 3 /day are designed in two versions: with horizontal and radial sedimentation tanks.

The first option requires a smaller area for the placement of technological tanks, the number and length of communications are reduced, and the possibility of organizing construction by the in-line method is provided. On fig. 17.7 shows the master plan of the biological wastewater treatment plant with a capacity of 25-70 thousand m 3 / day. Wastewater treatment facilities include mechanized MG-type screens, sand traps with circular motion and primary radial settling tanks. Biological wastewater treatment is carried out in aerotanks with a non-linearly dispersed wastewater inlet and pneumatic aeration. Disinfection of sewage is provided by liquid chlorine.

For the treatment of sewage sludge and sludge, they are fermented in digesters under thermophilic conditions, followed by drying on sludge beds. In addition to the treatment facilities on the territory of the station, there are: a raw sludge pumping station, a pumping and blowing station, a gas tank, a boiler room, a chlorination room, a block of industrial and amenity premises. Production and auxiliary buildings and structures are provided as part of a complex of treatment facilities.

Stations with a capacity of 1000-25,000 m 3 / day. In medium-sized cities, 50-100 thousand people live, and the amount of wastewater is 10-25 thousand m 3 / day.

JSC TsNIIEP of engineering equipment has developed a project for wastewater treatment plants with a capacity of 1000-25,000 m 3 / day, which include the following facilities:

Rice. 17.B. General layout of the station with a capacity of 25-70 thousand m 3 / day:

• 1 - receiving chamber; 2 - building for four mechanized gratings MG-11T)