Blower units for sewage treatment plants. Industrial blowers

Regulation of air supply in aerotechnics at treatment facilities is an opportunity to effectively save electrical energy.

The object of control is the technological process of wastewater treatment using bacteria contained in activated sludge. Wastewater is supplied to the aero section where activated sludge with bacteria is located. To activate bacteria and mix the sludge mixture, air from a turbo blower is supplied to the section. Control over the content of dissolved oxygen in the aero tanks is carried out by laboratory analysis, on the basis of which the air supply to the aeration tanks is controlled manually by a system of shutoff valves.

This system is complex in terms of requirements for control algorithms due to the influence a large number factors:

The amount of oxygen supplied;

Ambiguous behavior biological system activated sludge;

Temperatures environment;

The degree of concentration in wastewater of pollutants and other structures.

In general, the description similar systems does not fit into the traditional models of the theory of automatic regulation due to factors, the impact of which is almost impossible to predict. For example, air density and air compressibility are highly temperature dependent, and therefore the air control loops must be rebuilt depending on environmental conditions.

Continuous monitoring of the concentration of dissolved oxygen in aero tanks is a guarantee of high-quality cleaning and a reduction in energy consumption for blowers. The existing equipment at the enterprise (turbo blowers TV-175) and the method of laboratory measurement of the concentration of dissolved oxygen are obsolete and create a problem of high instability and cost overruns. electrical energy

To date, the most advanced is an automatic regulator in combination with an air blower for biological wastewater treatment 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 preliminary swirling of the flow, and a combination of the two named systems is also possible. Continuous oxygen measurement system, which includes a primary converter with a sensor immersed in water, as well as a secondary converter using modern technology microprocessor-based signal processing, generates a signal in accordance with the concentration of dissolved oxygen, which enters the installation for air injection, and then the amount of air entering the aerobics is automatically changed.

In accordance with the calculation method specific consumption air for the volume of incoming effluents, the amount of air supplied to the aeration tanks 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 oxygen consumption of air, per 1 mg of removed BOD - full.

For complete cleaning, BOD20 is assumed to be 1.1.

K 1 - the coefficient taking into account the type of aerothec, we take 2.0 for the first stage, 1.95 - for the second stage;

K 2 - coefficient depending on the immersion depth of the aerator:

2.08 = first stage;

2.92 - second stage

K t - coefficient taking into account the temperature of the waste water

K t = 1 + 0.02 (T w -20), where: T w average temperature water for summer period;

K 3 - coefficient of water quality, taken for urban wastewater 0.85.

C a - solubility of air oxygen in water, mg / l;

Tables of dissolved oxygen in air in Lex water - BOD 20 of purified waste water, taking into account the decrease in BOD during primary sedimentation. The data on BOD 20 were obtained from information on the qualitative composition of the normatively treated wastewater, by the testing laboratory of KZhUP "Unicom": BOD pol.post. 53.9 mg / l, BOD 5.1 mg / l.

K t = 1 + 0.02 (22.1-20) = 1.042

C a = 1 + C t, where: H is the immersion depth of the aerators, m;

C t is the solubility of oxygen in water. (Accepted according to table 27, Vasilenko. Water disposal. Course design).

Cal = 1 + 8.83 = 10.12

q airl = 1.1 = 18.75

q airll = 1.1 = 12.16

The daily air consumption according to the specific consumption is determined by the formula:

Q = q air + q average day , m 3 / day,

where: q air is the specific air consumption;

q average day - the average daily consumption of wastewater entering the treatment, m3 / day (28000 m3 / day).

Q I = 18.75 14000 = 262500 m 3 / day

Q II = 12.16 14000 = 170240 m 3 / day

Determine the hourly air consumption

Q 4 I = = 10938 m 3 / h

Q 4 II = = 7093 m 3 / h

The total consumption is

О р = Q 4 I + Q 4 II = 10938 + 7093 = 18031 m 3 / h

Thus, the required amount of air supplied to the aero tanks will be 18031 m 3 / h.

Currently, the following injection equipment has been installed:

1.Turbo blower TV-175 with a capacity of 10,000 m 3 / h - 2 pcs.

2. turbo blower TV-80 with a capacity of 6000 m 3 / h - 2 pcs.

3. turbo blower TV-80 with a capacity of 4000 m 3 / h - 2 pcs.

To obtain the estimated specific air consumption, it is necessary to include at least two blowers: one TV-175 blower with an installed electrical power of 250 kW and one TV-80 blower with an installed electrical power of 160 kW at a rated load.

Taking into account the physical and moral deterioration of the pressure equipment operating since 1983, it is proposed to install a single-stage centrifugal compressor with a multi-blade open turbine impeller in combination with an air supply control system using linear servomotors with the following requirements and indicators technological equipment:

Initial data

To provide 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 electric power of operating technological equipment - 320 kW - at 12000 m 3 / h

The installed electric capacity of the new technological equipment is 315 kW - at 16000 m 3 / h, and at 12000 m 3 / h - 249 kW.

We determine the annual savings in electrical energy when installing new equipment:

E e = (320 - 249) 0.75 24 365 10 -3 = 466 thousand kWh or 130.5 t of fuel equivalent

The cost of the saved fuel at a price of 1 ton of fuel equivalent = $ 210 (according to the Department of Energy Efficiency):

С = 130.5 × 210 = $ 27405 = 232942.5 thousand rubles.

Payback period of the event:

where K is the investment in the event, 2,000,000 thousand rubles;

C - savings from the implementation of the event, thousand rubles;

T = == 8.6 years.

Note: Clarification of all amounts of capital investments for the implementation of the proposed measures and the payback period is carried out after the development of design estimates

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, at treatment plants, aeration blowers of various capacities are installed, making the cleaning process efficient and environmentally friendly. The company "Megatekhnika MSK" on favorable terms is ready to supply interested enterprises with equipment with the parameters you need.

Basic requirements influencing the choice of blowers for water aeration

Natural aeration of water is an indispensable condition for the multiplication of water-purifying aerobic bacteria, in nature it occurs continuously. However, for an intensive, forced aeration system, much larger air volumes are required, for which a rotary or turbine-type water aeration blower is used, which meets such parameters as:

• the ability to supply dry air that does not contain microparticles of lubricant, wear products or other harmful impurities around the clock;
• maximum noiselessness of work;
• nominal capacity corresponding to the volume of processed wastewater;
• resistance to corrosion, temperature extremes and atmospheric precipitation;
• simplicity and simplicity in maintenance, operation, durability, reliability and energy efficiency of the structure.

What are the blowers for aeration of sewage treatment plants

A distinction is made between submersible blowers, which do not require additional cooling systems, and centrifugal blowers, with multistage compression. For small treatment facilities we recommend the equipment forcing air into the pneumatic system using a screw block. The principle of operation of the compression chamber of rotary blowers excludes the possibility of contact of oils with air, and the compressors themselves are particularly different low level noise and vibration, efficiency and compactness, which is important when placing treatment plants near residential areas. For treatment plants of large industrial enterprises more suitable compressors compressing the air by the movement of the pistons.

We will find the most effective solution for you!

The Moscow company "Megatekhnika MSK" offers a large assortment of blowers for aeration of wastewater treatment plants or artificial reservoirs, with parameters specified in each specific case. The possibility of changes in equipment performance is also taken into account, which is associated with possible seasonal fluctuations in the volume of wastewater, and, as a result, the difference in the consumption of compressed air. At competitive prices, we will equip your company with screw (rotary) or piston blowers from reputable manufacturers that are popular on the world and Russian markets. It is enough to make an application online, and our experts will contact you to clarify the details.

Compressorlow pressure or blower - equipment designed to supply air under pressure to the system biological treatment water. Wastewater treatment plant with oxygen pumped blowing stations, accelerate the decomposition of organic matter by aerobic bacteria. Aeration air contributes to the decomposition of biological contaminants with activated sludge. Aeration tank serves as a reactor for biological water purification.

Compressed air supply for biological treatment

Aerobic bacteria in the form of activated sludge are used in the biological treatment stage. Decomposition process organic compounds based on redox reactions. Under the influence of activated sludge, organic matter decomposes into methane and carbon dioxide .. In this case, bacteria multiply. The more oxygen in the water, the faster biomaterials are absorbed.

Air is supplied to the pre-aerator, where it bubbled with activated sludge and enters the aeration tank. Part of the sludge from the secondary settling tanks in the regenerator, after being treated with air, restores its activity and enters the aerator. The main flow of compressed air is directed to the aeration tank or biofilters with aeration, depending on the chosen scheme. So, the blower works at the biological stage, activating the aerobic bacteria. Only in conditions aquatic environment with an excess of oxygen, biological purification occurs by 98%.

The efficiency of the aeration tank depends on correct selection blowers by type and performance.

Blowing equipment classification

Air blowing stations must provide oxygen for biological water purification. Blower Requirements:

• the forced air must not contain impurities;
• low energy consumption and easy maintenance;
• mechanisms must work silently;
• match the line performance;
• have a regulated air supply, increasing energy efficiency.

Based on the criteria, the calculation and selection of units is carried out. There are two types of installations - submersible and centrifugal.

Submersible compressors are installed in the body of the aeration tank at depth, with piping for monitoring and controlling the suction filters. In the water column, there is an intense heat removal from the housing, the bearing assembly does not heat up. The compressor works more reliably, the overhaul period increases several times.

Centrifugal systems have high capacity and several compression stages. They use forced lubrication and water cooling.

According to the principle of operation, the installations are:

• piston;
• screw;
• vortex.

Piston units compress the gas in the chamber, creating pressure. The screw or rotary models are compact, they supply clean air without traces of oil to the system, they work quietly and around the clock. Rotary models have bearings outside the compression zone, the rotor is mounted on the shaft.

For air compression, devices are low-pressure, but with a higher capacity, or designed for high compression parameters with a lower flow rate. Graduation is necessary when choosing equipment for aeration tanks of different depths.

The main energy consumption of the treatment equipment is associated with the supply of air to the aerotanks. Reducing the energy component is possible if you use units with variable flow and compression.

Compressor manufacturers equipment advantages and disadvantages

Controlled industrial blowers have proven to be effective with a quick return on investment. The main supplier of equipment is Siemens. In Russia, up to 80% of unregulated installations are energy-consuming. Payback for new controlled installations in 2-4 years with annual energy savings of up to 35%. The company gives them on leasing terms. Adjustable blowers are offered by the Russian company Ekanit at lower prices.

A longtime compressor designer and manufacturer, the Lithuanian company Vienybe offers a wide range of rotary vortex compressors. The choice of models is extensive and meets modern needs.

For post-treatment drinking water air supply in the water treatment system will speed up the air bubbling process. The equipment is supplied by the EcoTechAvangard company. Blowers with a pressure of 1 bar are called low pressure, and are produced as equipment for water treatment plants.

Foreign representatives offer compressor equipment:

• EPU Systems specializes in EVW submersible models;
• Italian compressors of the Robuschi brand are characterized by high performance and quality of working surfaces;
• Japanese Hiblow models are compact, economical and reliable, new technologies are used;
• German equipment from Becker creates compact, reliable models that meet modern requirements.

Selection of a blower for the reconstruction of sewage treatment plants

The task of the production reconstruction is to replace the spent units with modern, economically viable ones. The blower must meet the needs of:

• increasing the performance of the aeration tank without increasing the volume;
• integrate variable blower control into an automated process;
• reduce energy consumption for air supply.

The equipment is selected taking into account the new developments of manufacturers.

• the use of fine bubble bubbling;
• replacement of blowers with submersible automated systems;
• installation of low pressure compressors.

In the process of modernization, a scheme of step-by-step replacement of compressors without stopping production can be applied.

Choice of blowers in new construction

When designing the biological stage of treatment facilities, proceed from the efficiency of decomposition of organic pollutants. A feature of the process is an oxygen-rich environment and a sufficient amount of activated sludge. Air supply is an integral part of cleaning, but the most energy intensive. Energy consumption can be reduced by installing latest models world and domestic developers. Among the equipment offered, you need to choose the best in terms of efficiency, price and quality.

The selection of the blower is carried out on the basis of the estimated air flow supplied to the system and the operating pressure. Feasibility studies for selection are the following criteria:

• decrease in energy load;
• process automation;
• reducing the cost of capital construction of a building for compressor equipment.

The project must meet the optimization of the process and reduce labor costs. This is the path offered by the world's leading manufacturers. Their models are compact, economical and safe to operate. The latest developments save up to 35% energy per year, reduce operating costs.

The cost of blowers depends on the use of new components that increase the functionality and economy of the model. The reliability of the device, the material for manufacturing the working mechanisms, the type of compressor - everything has a price. Expensive high quality units have a long service life and pay off within 2-4 years. It is profitable to install them in the long term.

Accessories for blower installation

When installing the blower in a biological treatment system, you will need additional elements process control. In this case, process sensors and actuators are ordered according to the diagram. Air distribution around the pool is carried out using disc and disc aerators installed on the air duct. Touchpad control of the unit with a controller allows you to adjust the operating mode in manual and automatic mode.

Aeration is the process of forced saturation of water with air, or oxygen. To support this process, a low-pressure compressor or aeration blowers are used, and its purpose is:

• Oxidation of iron compounds (deferrization of water) and manganese, which consists in the oxidation of iron and manganese compounds with oxygen. As a result, these compounds precipitate in the form of flakes, which are retained by a special backfill sediment filter.
• Removal of dissolved gases, including toxic ones, for example, hydrogen sulfide and methane.
• Water disinfection as a result of the destruction of organic substances contained in it, under the influence of oxygen.
• Removal of biocontamination: when water is saturated with oxygen, the number of beneficial aerobic bacteria grows, which process biomass into carbon dioxide and methane - biogas. Now the bioremediation process is used at all major wastewater treatment plants in Russia. The resulting biogas can also be pumped out of the treatment plant tanks using blowers for further use, for example, for the production of electricity or fuel for transport. However, this practice is not yet widespread in Russia.
• Maintaining the pond ecosystem due to the saturation of water with oxygen. In stagnant water, anaerobic bacteria begin to actively multiply under the influence of sunlight. As a result, the reservoir turns into a muddy swamp with unpleasant odor... Also, due to the insufficient concentration of oxygen in the water, a pestilence of fish and other beneficial organisms occurs.

There are 2 main types of oxygen saturation of a liquid: pressurized and non-pressurized.

Pressure aeration

A blower or compressor delivers compressed air through a tube that reaches about half the height of the aeration tower or oxidizer tank. The flow of air bubbles oxidizes foreign substances dissolved in water, and also removes gases dissolved in water (hydrogen sulfide, methane, carbon dioxide, etc.). These gases are removed through an air valve located at the top of the column.

From the column, water enters the backfill filter, where air-oxidized impurities are neutralized.

As a result, the unpleasant taste and smell of water disappears.

Rice. 1. Pressure aeration system (aeration column).

Advantages:

• Compact installation size.
• There is no need for a pumping unit to supply water to the consumer.
• Effective removal of gases dissolved in water.

Unpressurized, or open, aeration

For non-pressure aeration, an oxidizing tank with a jet break system is used. The water level in the tank is regulated by a level sensor, which sends a signal to solenoid valve... This valve closes, or opens, the pipe through which water is supplied to the container.

Air is supplied to the water column by a low-pressure compressor or blower through a pipe ending in a fine-bubble aerator. Passing through it, air forms many small bubbles that saturate the water with oxygen, oxidize impurities of iron and manganese.

Oxides, as in the previous case, are removed in the filter, into which water is supplied pumping unit from the oxidizing tank.

Rice. 2. Unpressurized aeration system

Advantages:

• Due to the prolonged interaction of water with the air flow in the tank, more contaminants are oxidized.
• Allows you to create a supply of water in case of its shutdown, which is especially important for private houses where water supply interruptions are possible.
• Suitable for homes with low water pressure.

The main disadvantage is that the process takes a long time.

Air blowers for water aeration: requirements and price

A blower must have a combination of the following properties for aeration to be effective:

• provide high performance with low pressure drop;
• do not contaminate the supplied air with oil vapor;
• work without stopping for a long time;
• the aeration blower should consume as little energy as possible, otherwise the cost of the process would be very high.

All these requirements the best way vortex blowers for aeration correspond - machines of dynamic action, which are capable of providing a clean air flow without pressure pulsations with a capacity of up to 2200 m3 / h and an overpressure of up to 1040 mbar. They can also be called vortex fans, or vortex vacuum pumps due to its versatility.

If you need to aerate large volumes, for example, ponds for industrial fish farming, or large sewage treatment plants, then higher capacity blowers may be needed. This niche is occupied by Roots rotary aeration blowers, which generate an air flow of up to 9771 m 3 / h.

For low volume systems such as aeration towers, a dry rotary vane compressor such as a Becker or VARP Rigel can be used instead of a vortex blower to aerate the water. Their productivity is limited to 500 m 3 / h, but the overpressure is up to 2200 mbar.

The blower for water aeration is selected based on the requirements of the technological process, but if the price is critical, then first of all pay attention to the VARP Alpha vortex blowers. In general, the most affordable price is for vortex blowers, followed by rotary vane blowers, and the most expensive, but also the most powerful, are rotary blowers.

Vortex aeration blowers

Vortex blowers, for which aeration is one of the main applications, are presented in a wide range of sizes and have a large price range, which allows you to choose the most efficient car exactly for your task.

Blowers for water aeration, which can be bought in our catalog, are represented by the following brands.

VARP

This is a new brand on the Russian market, which is represented by a wide range of vortex blowers that meet all modern requirements for machines of this type. The main advantages of VARP gas blowers:

• affordable price with high quality workmanship and assembly;
• durability, thanks to the use of original SKF and NSK bearings, a service life of more than 20 thousand hours of continuous operation;
• high reliability is ensured by the use of high-strength aluminum alloy and simple construction;
• excellent performance thanks to modern methods design.

If you are looking for a standard blower for aerating water, such as a pond, then check out the Alpha series. They can provide high airflow with low pressure drop. Their productivity is up to 2050 m3 / h, and the overpressure is up to 670 mbar.

For deep ponds or small containers better fit the Beta series, which provides high differential pressures up to 1040 mbar with low capacities up to 170 m 3 / h.

For industrial applications such as sewage treatment plants or large fish farms, the powerful Gamma series aeration blower is needed. It provides a high air flow up to 750 m 3 / h at an overpressure of up to 1020 mbar.

Busch samos

High-performance German blowers, which are often used for aeration of water in large reservoirs and sewage treatment plants. Their productivity is up to 2640 m 3 / h, and the pressure drop in compressor mode is up to 500 mbar.

Benefits of Busch blowers:

• Energy efficient motors are used, which can reduce power consumption. This is especially true for industrial wastewater treatment plants, since aeration is energy-intensive.
• Quality German equipment at a low cost, since Busch has set special prices for Russia.
• They can work for a long time without stopping and do not require maintenance.
• Easy installation in horizontal or vertical position.

SEKO BL

Economy class SEKO blowers meet modern requirements for vortex blowers. Affordable price combined with reliability and high quality devices. They can also aerate reservoirs, providing a large air flow with a capacity of up to 1110 m 3 / h at a pressure drop of up to 650 mbar, and have a number of advantages:

• Equipped with two-pole electric motors, which allow continuous operation without interruption.
• Wide the lineup allows you to choose a blower and aerators with optimal parameters and not overpay for more powerful blowers if they are not needed.
• Minimum noise and vibration thanks to built-in mufflers and no imbalance.

FPZ SCL

The Italian high-pressure blowers FPZ SCL create a maximum differential pressure of 650 mbar and are available in models with a capacity of up to 1022 m 3 / h and a power of up to 22 kW. This blower is great for both aeration small ponds for fish, and for large sewage treatment plants.

Main advantages:

• Only original SKF and NSK bearings are used, which provide at least 25 thousand hours of continuous operation.
• Low energy consumption, thanks to the use of Italian high efficiency Bonora Motori electric motors.
• Even greater energy savings are provided by variable frequency control up to 70 Hz, which allows you to fine-tune the performance according to the set parameters.
• Long-term operation is possible thanks to the built-in motor overheating protection.

Becker sv

Another brand of vortex gas blowers that are produced and assembled in Germany. They create a differential pressure of up to 865 mbar and provide a continuous air flow with a capacity of up to 1050 m 3 / h and an output of up to 15 kW.

Becker blowers are used for aeration - to purify and oxygenate water in fish ponds and treatment facilities, and although their price is higher than, for example, VARP or SEKO, they have won an excellent reputation and are very popular in Russia.

Advantages:

• Economical energy consumption, which is most important for high-performance machines.
• Completely oil-free thanks to the use of non-lubricated bearings.
• Manufacturers guarantee a high resource - at least three years of continuous operation.
• The use of the built-in rotor speed control system increases efficiency, increases the service life and allows you to adjust the performance to the optimal value for each specific task.

Rotary blowers for aeration

Vortex blower is not the only blower suitable for water aeration - for a large aeration tank it makes sense to buy a high-performance Roots blower.

There are 2 variants of rotary blowers in our catalog:

• VARP Altair provide a gas flow with a capacity of up to 7548 m 3 / h and an overpressure of up to 980 mbar.
• LUTOS DT operate with a flow rate up to 9771 m 3 / h and create a differential pressure of up to 1000 mbar.

These machines outperform vortex machines in performance, but they are more expensive. They have all the properties required for the devices of aeration plants of treatment facilities:

1. Environmental friendliness: they do not pollute the pumped gas with oil vapor, since the flow path is reliably isolated from the oil sump by a dynamic labyrinth seal.
2. Low noise and vibration levels.
3. High efficiency.
4. Reliability and stable performance.
5. The resource of work is not less than 100 thousand hours.
6. The rotors are carefully balanced to rotate at high speeds and deliver high performance in a small footprint.
7. It can work for a long time without interruption.

Waste water aeration blowers

Aeration blowers are presented in a wide range of sizes, so to buy suitable model, it should be remembered that the main purpose of wastewater aeration is to supply aerobic microorganisms that form sludge, the required amount oxygen. As well as providing mixing to create conditions for the interaction of bacteria with organic matter.

Wastewater aeration accounts for 50..90% of the total capacity consumed by sewage treatment plants. This is a very energy-consuming process, therefore, electric blowers for aeration are selected based on the conditions for optimal operation.

How is wastewater treatment carried out?

There are many options for wastewater treatment systems. Blowers are used in aerobic cleaning systems to supply oxygen to aerobic bacteria that recycle organic pollutants. To understand how the purification process takes place, consider a bioremediation system with a membrane unit.

Rice. 3. Biological wastewater treatment system with a membrane block

At first wastewater enter a mechanical cleaning device, for example, sand traps or special nets.

After that, they go to the homogenizer, in which the waste waters with different composition are actively mixed, and then they are moved to the biological purification system by liquid pumps. This system consists of a denitrifier and a nitrifying aeration tank.

The anoxide mode is set in the denitrifier - there is no dissolved oxygen in the water, but there is chemically bound oxygen in the form of nitrites and nitrates. Organic pollution contained in wastewater is oxidized by activated sludge (AI) to gaseous oxides and molecular nitrogen. To prevent sludge from settling on the bottom, an agitator is installed in the anoxide zone.

The aeration tank is an important part of the treatment system, in which the biological treatment process takes place. In most cases, it is a single or multi-chamber reservoir. rectangular section made of concrete with waterproofing coating through which the sewage passes. The contaminated liquid is constantly mixed with activated sludge (colonies of beneficial aerobic microorganisms, bacteria and protozoa), and an air stream is forced into the container. It saturates the water with oxygen, providing the vital activity of beneficial microorganisms, and also maintains the sludge in suspension. Compressors or blowers supply compressed air through the water column to saturate it with oxygen through fine bubble aerators located at the bottom of the aeration tanks.

Compressors or blowers supply compressed air through the water column to saturate it with oxygen through fine bubble aerators located at the bottom of the aeration tanks.

To oxidize organic substances and ensure nitrification, the concentration of oxygen dissolved in water should be of the order of 2..3 g / m 3, and the concentration of AI - of the order of 4..10 g / m 3.

In this version of the treatment system, instead of a secondary settling tank, a block of fine-pored membranes is installed in the nitrifying aeration tank, in which pure water and AI are separated.

Filtered water (permeate) is supplied by a water pump to a container with clean water, from where it is transferred to the ultraviolet disinfection system, after which it is supplied to the consumer.

The separated activated sludge from the nitrifier is pumped to the denitrifier. To remove phosphorus, a solution of ferric chloride is fed into the moving AI stream. Thanks to the circulation of AI, its concentration is maintained in the biological treatment zone.

Calculation of aeration blower (aeration tank). How do you measure performance?

The aeration process takes place in the aerobic zone, so in fact we are solving the problem of how to choose a blower for the aeration tank.

Water from sewage flows into aeration tanks, where it must be saturated with a sufficient amount of oxygen to oxidize organic matter.

Therefore, it is possible to choose a blower according to the size of the tank, knowing the dimensions of the water treatment system, the biochemical oxygen demand (BOD) of wastewater and their average daily consumption, it is possible to determine the required volumetric flow rate and air pressure that will be supplied to the aeration tank.

Specific air consumption required for aeration:

q aeration = 2 L a/kh (m 3 air / m 3 waste water),

h , m - the working depth of the aeration tank - the depth to which the aerator is immersed;

L a , kg / m 3 - BOD of wastewater, which is supplied to the aeration tank (0.002..0.003 kg / m 3 for the system considered above);

k , kg / m 4 - coefficient of air utilization, which depends on the ratio of the areas of the aerators and the aeration tank and on the ratio between the depth and width of the aeration tank. For example, when air is pumped through perforated pipes, it is only 0.006 kg / m 4, and when using more effective system porous plates, it is 2 times more than 0.012 kg / m 4.

The air flow to be supplied to the aeration tank by the blower is:

Q =q a eration Q w(m 3 / h),

where Q w, m 3 / h - average daily wastewater consumption. If this parameter is not known to you, then as a first approximation it can be estimated, knowing the working volume of the aeration tank V slave / t 1 hour = Q w(m 3 / h).

Flow rate Q and the performance of the blowers will be determined. To provide this flow, several blowers with a capacity of Q i working in parallel.

How to choose a blower for aeration tanks according to the pressure value?

The required pressure is determined based on the depth of the aeration tank:

p = p atm + Δ p + Δ p g (mbar) ,

p atm - Atmosphere pressure, approximately equal to 1000 mbar;

Δ p = Δ p t+ Δ p a(mbar), where Δ p t- pressure loss when the air flow moves from the blower discharge pipe to the outlet of the aerator. The geometry of the air ducts should be chosen so that this value does not exceed 30..35 mbar. Δ p a- pressure losses in aerators, which depend on a specific model and are given in the attached technical documentation, about 15..30 mbar);

p g =ρgh is the pressure of the water layer in the aeration tank, where ρ - the density of the liquid, g - acceleration of gravity.

Most often, the depth of the aeration tanks is from 1 to 7 m, therefore, the required overpressure is 100..800 mbar, which fits well into the pressure range created by vortex and rotary gas blowers.

Knowing the value of productivity Q i and pressure p , you can select blowers for aeration of water at the operating point using the calculator on the page

Modern treatment facilities are equipped with aeration systems that purify drinking and waste water by artificially saturating them with air, which oxidizes the contained in them organic matter... To implement this process a specialized compressor is used. Since it generates pressure up to 1 bar, it is called a low pressure or blower. The EcoTechAvangard company offers blowers for sewage treatment plants from many leading manufacturers at competitive prices.

Blower working principle

Wastewater treatment plants can be equipped with reciprocating or screw compressors. The principle of operation of devices of the first type is based on the compression of gas when the pistons move. Blowers of the second type work with a screw block (rotor) that pumps the air-oil mixture into the pneumatic system. Screw models are most often used in small enterprises because they are compact, economical, can operate around the clock and have low vibration and noise levels. The principle of their operation eliminates the contact of air with oil in the compression chamber, therefore, high-quality oil-free air is obtained at the outlet.

Types of compressors for sewage treatment plants

Submersible. These blowers are installed underwater and operate silently. Therefore, sewage treatment plants equipped with these devices can be located near residential premises. Submersible compressors do not need an additional cooling system, since the liquid in which they are located independently removes excess heat, which increases the performance of this equipment and significantly extends its service life. The management of the operation of such installations is fully automated. Pressure sensors installed in the system monitor the condition of the suction filters.

Centrifugal. Such blowers are powerful and are installed in waste treatment plants with high performance. By design, compressors of this type are classified as low-pressure devices in which multistage compression is carried out. The power of the centrifugal mechanisms requires forced lubrication and the installation of a water cooling system, in some models.

Blower manufacturers

EPU Systems. The submersible models of the EVW series are installed at the bottom of the aeration tanks, so the noise they generate is absorbed by the water. In addition, the liquid cools the body of the device, thus increasing its service life.

Robuschi. Italian compressors of the Robuschi brand are distinguished by high performance and can be installed in large production facilities. All parts of the devices are made of hardened steel and meet modern European standards quality.

Hiblow. Models of the Japanese company Hiblow are compact, low noise and high reliability... They are widely used in everyday life and in enterprises. low power... Their principle of operation is based on the use of electromagnetic vibration, which reduces power consumption and increases the efficiency of installations.