Aeration Wastewater- saturation of the liquid with oxygen, giving life to bacteria that process toxins, organic substances, forming sludge. Bubble streams are created by diffusers installed at the bottom of the treatment pond.
Large volumes required compressed air during continuous operation of the equipment, which can be provided by aeration blowers.
equipment requirements
Compressors for wastewater treatment plants are selected based on the following conditions:
- The first thing you should pay attention to when choosing a compressor is the depth of the reservoir. Every 10 m of liquid column creates a pressure of 1 bar. Accordingly, a blower for treatment facilities must create a working pressure sufficient to pump air to the bottom level. As a rule, the depth of treatment facilities does not exceed 7 meters (0.7 bar - 70 kPa), thus, most models of centrifugal and VRMT blowers manufactured by Thermomechanika LLC are suitable for aeration.
- Performance, which is calculated based on the size of the reservoir, the number and characteristics of diffusers. The volume of required air can be from 100 to 50 thousand cubic meters per hour.
- "purity". The air must not contain impurities of lubricating coolants, which will adversely affect the vital activity of bacteria.
- Simplicity and reliability. The low pressure compressor will have to work non-stop. For water aeration, machines with direct drive from the motor shaft, without gearboxes and V-belts, are suitable. Centrifugal blowers from the Tremomechanika plant have a resource of more than 100 thousand hours of continuous operation.
- Low noise. Increasingly, small sewage treatment plants serving the villages of private households, commercial enterprises. Proximity to housing, excludes the use of equipment exceeding sanitary norms by noise level. Acoustic indicators of vortex and centrifugal superchargers of Thermomechanics lie in the range of 50-75dB, which fully complies with the requirements of SanPiN.
- Profitability. Energy consumption is directly dependent on the efficiency and power of the blower motor. Rotary blowers for aeration have a higher efficiency, however, "gluttonous" vortex blowers have an advantage in terms of noise, reliability and cleanliness of the injected air
In order not to overpay for electricity, you need an accurate calculation of a sufficient amount of air per unit of time, knowing which, a blower of a certain capacity is selected.
The use of automatic control systems also allows you to reduce the operating time of the engine, and, accordingly, electricity bills.
How to choose
To buy the optimal type and model of the blower, to minimize the cost of wastewater aeration, call the sales department of the Thermomechanika plant, or request a call back at a convenient time.
The service engineer will preliminary calculations air flow, will suggest the equipment most suitable for a particular situation.
Prices for products are announced at the request of the client, after agreeing on the model of the blower, or the terms of reference for the design of the installation.
Wastewater treatment plants use blowers for two processes:
1. Aeration - forced saturation of wastewater with air to stimulate the reproduction of aerobic bacteria. These beneficial bacteria decompose the biomass contained in the water into methane and carbon dioxide. This process occurs at all major facilities in Russia. Depending on the volume of incoming wastewater, the intensity of aeration is changed by adjusting the performance of the blowers.
2. Removal of biogas resulting from decomposition by bacteria organic matter contained in wastewater. Biogas, consisting of methane and carbon dioxide, is pumped out by a blower from tanks and delivered to the consumer. Unfortunately, in Russia the work of blowers for pumping out biogas is not yet very common. However, experience in the utilization of biogas is gradually being introduced in the vastness of our country.
3 most popular blower models for wastewater treatment plants
We present 3 models of blowers most suitable for the main tasks of wastewater treatment plants.
This model has an engine power of 4 kW and provides a pressure of 400 mbar (0.4 atmospheres) with a capacity of 200 m3/hour. Among vortex blowers small size This model is very successful in terms of power and performance ratio. This model has the best price solution in the class.
The power of this unit is 11 kW, it provides a pressure of 600 mbar (0.6 atmospheres) with a capacity of 270 m3 / h. This model is powerful enough for a vortex blower. In our opinion, 11 kW is the maximum power of a vortex blower, which is advisable to use in wastewater treatment plants. The fact is that more powerful models of vortex fans are already compared in price with blowers of other types, and although they outperform them in terms of ease of use and durability, they are much inferior to them in terms of energy efficiency.
It is no secret that blowers for sewage treatment plants should not have oil impurities in the exhaust. Model SDT 22 has a power of 30 kW, a pressure of 1000 mbar (1 atmosphere) with a capacity of 1100 m3/h. This very powerful unit has a very high efficiency, but a shorter service life compared to the previous two models, and also requires more expensive and qualified maintenance. Thanks to the Lutos screw block, this blower has an absolutely clean exhaust without oil impurities.
If none of the above 3 models fit
No matter how popular these models are, in many cases an individual selection of the blower according to the parameters is required. Pick up desired model, knowing the required air flow and pressure, you can home page our resource.
For selection and select the type of equipment "blower", then enter the desired parameters. A reference base of more than 400 blowers is at your service various types and manufacturers.
Aeration systems, which are equipped with industrial and local treatment facilities, are designed for artificial enrichment of wastewater with oxygen, which oxidizes iron compounds and other impurities. For this, special vacuum equipment is used that meets certain standards and requirements. In particular, aeration blowers of various capacities are installed at treatment plants, making the cleaning process efficient and environmentally friendly. Company "Megatekhnika MSK" favorable conditions is ready to supply interested enterprises with equipment with the parameters you need.
The main requirements influencing the choice of blowers for water aeration
Natural aeration of water is an indispensable condition for the reproduction of aerobic bacteria that purify water; in nature, it occurs continuously. However, an intensive, forced aeration system requires much larger volumes of air, for which a blower is used to aerate water of a rotary or turbine type, which meets such parameters as:
- the ability to supply dry air around the clock, not containing lubricant microparticles, wear products or other harmful impurities;
- maximum noiselessness of work;
- nominal capacity corresponding to the volume of processed wastewater;
- resistance to corrosion, temperature extremes and the effects of precipitation;
- simplicity and unpretentiousness in maintenance, operation, durability, reliability and energy efficiency of the design.
What are blowers for aeration of sewage treatment plants
There are submersible blowers that do not need additional systems cooling, and centrifugal, with multi-stage compression. For small wastewater treatment plants, we recommend equipment that pumps air into the pneumatic system using a screw block. The principle of operation of the compression chamber of rotary blowers eliminates the possibility of contact between oils and air, and the compressors themselves are distinguished by a particularly low level of noise and vibration, efficiency and compactness, which is important when treatment plants are located near residential areas. For treatment complexes of large industrial enterprises, compressors that compress air with the movement of pistons are more suitable.
We will find the most effective solution for you!
The Moscow company "Megatechnika MSK" offers a wide range of blowers for aeration of treatment facilities or artificial reservoirs, with parameters specified in each case. The possibility of changing the performance of the equipment is also taken into account, which is associated with possible seasonal fluctuations in the volume of wastewater, and, as a result, the difference in compressed air consumption. By favorable prices we will equip your enterprise with screw (rotary) or piston blowers from reputable manufacturers that are popular in the world and Russian market. It is enough to make an application online, and our experts will contact you to clarify the details.
Regulation of air supply in aerotechs at treatment facilities is an opportunity to effectively save electrical energy.
The control object is technological process wastewater treatment using bacteria contained in activated sludge. Waste water is supplied to the aerotec sections, where activated sludge with bacteria is located. To activate bacteria and mix the sludge mixture in the section, air is supplied from turbo blowers. Control over the content of dissolved oxygen in aeration tanks is carried out by laboratory analysis, on the basis of which the air supply to the aeration tanks is regulated by the system stop valves in manual mode.
This system is complex in terms of requirements for control algorithms due to the influence of a large number of factors:
The amount of oxygen supplied;
Ambiguities in the behavior of the biological system of activated sludge;
Temperatures environment;
Degrees of concentration of pollutants in wastewater and other structures.
In general, the description of such systems does not fit into the traditional models of the theory of automatic control due to factors, the account of the influence of which is almost impossible to predict. For example, air density and air compressibility depend significantly on temperature, and therefore the air supply control loops must be reconfigured depending on environmental conditions.
Continuous monitoring of the concentration of dissolved oxygen in aerotechs is the key to high-quality cleaning and reducing power consumption on blowers. Available equipment at the enterprise (turboblowers TV-175) and method laboratory measurement dissolved oxygen concentrations are obsolete and create the problem of high instability and overruns electrical energy
To date, the most advanced is an automatic regulator in combination with an air blower for the biological treatment of wastewater and a continuous oxygen measurement system. The performance of such installations is controlled by means of a diffuser guide vane with adjustable blades or an inlet guide vane with a preliminary flow swirl, and a combination of the two named systems is also possible. A continuous oxygen measurement system that includes a primary transducer with a sensor immersed in water, as well as a secondary transducer using modern technology microprocessor signal processing, generates a signal in accordance with the concentration of dissolved oxygen, which enters the air injection unit and then automatically changes the amount of air entering the aerotheca.
In accordance with the calculation method specific consumption air to the volume of incoming wastewater, the amount of air supplied to the aerotheca was determined - 18030 m 3 / h.
Let's calculate the specific air consumption for the volume of incoming wastewater 28000 m 3 /day.
Specific air consumption
where: q 0 - specific consumption of oxygen in the air, per 1 mg removed BOD-total.
For complete purification of BOD20, 1.1 is taken.
K 1 - coefficient taking into account the type of aerotheca, we take 2.0 for the first stage, 1.95 - for the second stage;
K 2 - coefficient depending on the depth of immersion of the aerator:
2.08 = first stage;
2.92 - second stage
K t - coefficient taking into account the temperature of wastewater
K t \u003d 1 + 0.02 (T w -20), where: T w is the average water temperature for summer period;
K 3 - water quality coefficient, taken for urban wastewater 0.85.
Са – solubility of air oxygen in water, mg/l;
Tables of air oxygen dissolution in Lex water - BOD 20 of treated waste water, taking into account the decrease in BOD during primary settling. Data on BOD 20 were obtained from information on the qualitative composition of standard treated wastewater, by the testing laboratory of KZhUP "Unicom": BOD pol.post. 53.9 mg/l, BODpol.pur. 5.1 mg/l.
K t \u003d 1 + 0.02 (22.1-20) \u003d 1.042
С а = 1+ · С t, where: Н – immersion depth of aerators, m;
C t is the solubility of oxygen in water. (We accept according to table 27, Vasilenko. Water disposal. Course design).
Сal \u003d 1 + 8.83 \u003d 10.12
qairl = 1.1 = 18.75
qairll = 1.1 = 12.16
Daily air consumption by specific consumption, we determine by the formula:
Q = q air + q average day , m 3 / day,
where: q air - specific air consumption;
q cf.day - the average daily consumption of wastewater entering the treatment, m 3 / day (28000 m 3 / day).
Q I \u003d 18.75 14000 \u003d 262500 m 3 / day
Q II \u003d 12.16 14000 \u003d 170240 m 3 / day
Determine the hourly air flow
Q 4 I \u003d \u003d 10938 m 3 / h
Q 4 II \u003d \u003d 7093 m 3 / h
Total consumption equals
O p \u003d Q 4 I + Q 4 II \u003d 10938 + 7093 \u003d 18031 m 3 / h
Thus, required amount air supplied to the aerotheca will be 18031 m 3 / h.
The following injection equipment is currently installed:
1. turboblower TV-175 with a capacity of 10,000 m 3 / h - 2 pcs.
2. turboblower TV-80 with a capacity of 6000 m 3 / h - 2 pcs.
3. turboblower TV-80 with a capacity of 4000 m 3 / h - 2 pcs.
To obtain the calculated specific air consumption, it is necessary to turn on at least two blowers: one TV-175 blower with an installed electric power of 250 kW and one TV-80 blower with an installed electric power of 160 kW at rated load.
Taking into account the physical and moral deterioration of the injection equipment operating since 1983, it is proposed to install a single-stage centrifugal compressor with a multi-blade open turbine-type impeller in combination with an air supply control system using linear servomotors with the requirements and indicators listed below technological equipment:
Initial data
To ensure air supply in the amount of 12000 m 3 /h, it is necessary to turn on two TV-80 blowers with a total power of 320 kW.
Installed electrical power of the operating technological equipment - 320 kW - at 12000 m 3 / h
The installed electric capacity of the new technological equipment is 315 kW at 16,000 m 3 /h, and at 12,000 m 3 /h - 249 kW.
We determine the annual savings in electrical energy when installing new equipment:
E e \u003d (320 - 249) 0.75 24 365 10 -3 \u003d 466 thousand kWh or 130.5 tce
The cost of saved fuel at the price of 1 ton of fuel equivalent = $210 (according to the Department of Energy Efficiency):
C \u003d 130.5 210 \u003d $ 27405 \u003d 232942.5 thousand rubles.
Payback period of the event:
where K - investment in the event, 2000000 thousand rubles;
C - savings from the implementation of the measure, thousand rubles;
T = == 8.6 years.
Note: Clarification of all amounts of capital investments for the implementation of the proposed measures and payback periods is carried out after the development of design estimates
In Russia, wastewater treatment plants are one of the main consumers of electricity, most of goes to power the turbo blowers. Typically, multi-stage turbocompressors are used to supply air for the treatment of domestic, storm and industrial wastewater. But practice shows that it is more profitable to install easily controlled industrial blowers that save up to 50% of electricity, and their purchase pays off in 3 years.
These savings come from variable turbochargers delivering just the right amount of air for the engine. biological treatment drains depending on seasonal temperature fluctuations. At the same time, the efficiency of such equipment is more than 80%. It should be noted that the maintenance and repair of turboblowers takes no more than 1% per year of the total cost of the units.
A distinctive feature of industrial blowers is the presence of adjustable guide vanes on suction and discharge. The air adjustment range is maximum (from 45 to 100%), while the efficiency decreases by only 3-4%. There is blower equipment with rotary-blade mechanisms that allow you to adjust the amount of air masses supplied to the aerotanks, so you can adjust the degree of aeration.
Controlled industrial blowers have the following technical characteristics:
- productivity - from 1000 to 120000 m3 / h;
- adjustment range - from 45 to 100%;
- power - from 34 to 3300 kW;
- Efficiency - from 88 to 92%.
Types of blowers
Exist different kinds industrial blowers that are installed at large treatment plants and industrial enterprises. Let's consider each type separately.
Rotary blowers
These blowers use an oil-free method of compressing and supplying air. The principle of operation of such equipment is as follows: two three-toothed (three-lane) rotors, which are located parallel to the motor, rotate in the housing in different directions, acting as a piston. Thus, the non-contact running of the rotors does not require lubrication.
Rotary blowers
This equipment belongs to vertical air flow units. The blowers include a discharge element with three-toothed rotors with a belt drive, noise and suction silencers, safety valves, compensator check flaps, two pressure gauges or a clogged filter indicator. The oscillating frame of the motor automatically tightens the belts, which ensures efficient work drive without special service personnel.
Centrifugal
According to the principle of work this equipment refers to dynamic radial compressors. The pressure and compression of the air is created by the operation of the impeller stages, accelerating the medium and then slowing it down with high-efficiency diffusers with a large radius, while a certain pressure drop is created at the exit.
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