KAESER blowers for wastewater treatment plants. Industrial Blower Compressor Blower for Wastewater Treatment Plant Aeration Systems
Blowers for treatment facilities are used to carry out two technological processes:
- For aeration. The aeration process is a forced saturation Wastewater air to stimulate the growth of aerobic bacteria. These beneficial bacteria break down the biomass contained in the water into methane and carbon dioxide. This process occurs at all large structures in Russia. Depending on the volume of incoming wastewater, the intensity of aeration changes by adjusting the performance of the blowers.
- Removal of biogas formed as a result of bacterial decomposition of organic substances contained in wastewater. Biogas, consisting of methane and carbon dioxide, is pumped out of the tanks by a blower and delivered to the consumer.
To solve the assigned problems, TSEPRIKON JSC offers two types of blowers for wastewater treatment plants: rotary and screw. With their help, you can solve all the assigned tasks in the shortest possible time. Our company’s employees can select blowers for wastewater treatment plants directly according to customer specifications.
Specifications
Modular design
IN in some cases, when Customers do not have separate room to install blowers, our company offers to solve this problem by mounting the equipment in block containers. In this case, you get an autonomously operating compressor station for the production compressed air low pressure completely ready for use. All systems are mounted inside the container. To start the station, you only need to supply electricity and connect the air supply network to a common collector.
How to order equipment
If you need a blower for wastewater treatment plants, and you are ready to buy it, our company has the opportunity to supply it to you favorable conditions. JSC "TSEPRIKON" is a supplier of this equipment in the Russian Federation. Our company’s employees will select the right equipment for you, which will fully comply with your technical specifications. In addition, we are ready to carry out installation, commissioning works and successfully put the equipment into operation at the Customer’s territory. Under an additional agreement, our service engineers will provide after-sales service for compressors throughout the entire service life of the equipment.
Currently, our public utilities are experiencing certain difficulties. Communications are deteriorating, the quality of industrial and domestic wastewater treatment is deteriorating. Therefore, quite often it is necessary to reconstruct and modernize treatment facilities and utility lines based on new technologies.
When reconstructing existing treatment facilities, the main condition is the optimization of capital costs, achieving efficient work all technological areas and reducing operating costs. One of the ways to increase the efficiency of enterprises is the use of energy-saving technologies and high-quality equipment.
It is no secret that the main operating costs at wastewater treatment plants are energy costs, the lion's share of which is the cost of aeration.
For achievement maximum efficiency and reducing energy costs associated with aeration processes, it is necessary to choose wisely.
Due to the fact that wastewater flows unevenly to treatment plants, it is necessary to reduce or increase the air supply for aeration, depending on the concentration of oxygen dissolved in it. To minimize the cost of electricity required for operation blowers for wastewater treatment plants , it is necessary to regulate the performance of blower units depending on the oxygen demand. The blower station must have a fairly wide control range and supply the required amount of air to the system with minimal costs for electricity, thereby saving quite a lot of money on paying for expensive electricity. This can be achieved through proper selection KAESER blowers .
A number of treatment facilities have averaging pools that ensure a uniform supply of wastewater for subsequent treatment, and it would seem that in this case there is no need to regulate the air supply for aeration, but there are many other factors that affect the supply of the required amount of air. The main factor influencing the change in air supply is temperature.
The density of air and the concentration of oxygen dissolved in it depend significantly on temperature. Taking this into account, namely, adjusting the change in air supply for aeration based on ambient temperature, is a powerful potential for energy savings.
Competent selection blowers for wastewater treatment plants is the key to future savings for the enterprise, highly efficient production due to a significant reduction in operating costs. The configuration of the blower station directly depends on the operating conditions. When selecting blowers for wastewater treatment plants everything must be taken into account: air humidity, altitude above sea level at the location where the blower is installed, ambient and intake air temperature, pressure loss in the air network.
Special software helps you take all these factors into account and choose the right blower.
Blowers for wastewater treatment plants KAESER have a different design from other blowers, which allows them to be installed close to each other (service is carried out from the front of the unit), due to this, the units require significantly less area for installation.
Moreover blowers for wastewater treatment plants can be manufactured for outdoor use and placed directly on the street, near the aeration tank. Thus, there is no need for the construction or reconstruction of a room to accommodate a blower station, as well as subsequent costs associated with the operation of the room.
Installation blowers for outdoor aeration, directly next to the aeration tank, it avoids the cost not only of constructing premises to house the units, but also significantly reduces the length of the pneumatic line. In this case blowers for aeration operate even more efficiently, since there is virtually no pressure loss on the line and less drive power is required to supply the required amount of air.
Applying systems approach to selection blowers for wastewater treatment plants , taking into account all the factors influencing the air supply process, you can achieve the desired result, significantly reduce operating costs and increase the energy efficiency of the facility.
Aeration is the process of forced saturation of water with air, or oxygen. To ensure this process, a low-pressure compressor or aeration blowers are used, and its purpose is:
- Oxidation of iron compounds (deferrification 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 the organic substances contained in it under the influence of oxygen.
- Removal of biocontaminants: When water is saturated with oxygen, the number of beneficial aerobic bacteria increases, which process biomass into carbon dioxide and methane - biogas. Now the biotreatment process is used at all large treatment plants in Russia. The resulting biogas can also be pumped out of wastewater treatment plant tanks using blowers for further use, for example to produce electricity or transport fuel. However, this practice is not yet widespread in Russia.
- Maintaining the Pond Ecosystem due to the saturation of water with oxygen. In standing water under the influence sun rays Anaerobic bacteria begin to actively multiply. As a result, the reservoir turns into a muddy swamp with unpleasant smell. Also, due to insufficient concentration of oxygen in water, death of fish and other beneficial organisms occurs.
There are 2 main types of oxygen saturation of liquids: pressure and non-pressure.
Pressure aeration
A blower or compressor delivers compressed air through a pipe that extends approximately halfway up the height of the aeration column, 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 and others). These gases are removed through an air valve located at the top of the column.
From the column, water flows into the filling filter, where impurities oxidized by air 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.
Gravity or open aeration
For non-pressure aeration, an oxidation tank with a jet breaking 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 into the water column by a low-pressure compressor or blower through a pipe ending in a fine-bubble aerator. Passing through it, the air forms many small bubbles, which saturate the water with oxygen and oxidize impurities of iron and manganese.
Oxides, as in the previous case, are removed in a filter into which water is supplied pumping unit from the oxidation tank.
Rice. 2. Gravity 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 a power outage, which is especially important for private houses where interruptions in water supply are possible.
- Suitable for homes with low water pressure.
The main disadvantage is that the process takes a lot of time.
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 a small pressure drop;
- do not pollute the supplied air with oil vapor;
- long time work without stopping;
- The aeration blower must consume as little energy as possible, otherwise the cost of the process will be very high.
All these requirements the best way correspond to vortex blowers for aeration - dynamic machines that 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 fans. vacuum pumps, thanks to its versatility.
If large volumes need to be aerated, for example, ponds for industrial fish farming, or large wastewater treatment plants, then larger capacity blowers may be needed. This niche is occupied by rotary aeration blowers of the Roots type, which create an air flow of up to 9771 m 3 /h.
For small volume systems, such as aeration columns, a dry rotary vane water aeration compressor, such as a Becker or VARP Rigel, can be used instead of a vortex blower. Their productivity is limited to 500 m 3 / h, but the excess pressure is up to 2200 mBar.
The blower for water aeration is selected based on the requirements technological process, but if price is critical, then first of all pay attention to VARP Alpha vortex gas blowers. In general, vortex blowers have the most affordable price, followed by vane rotor 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 standard sizes and have a wide price range, which allows you to choose the most effective machine specifically for your task.
Blowers for water aeration, which can be purchased 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 model range vortex blowers corresponding to all modern requirements for machines of this type. The main advantages of VARP gas blowers:
- reasonable price with high quality manufacturing 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 design;
- excellent performance thanks to modern methods design.
If you are looking for a standard blower to aerate water such as a pond, then look no further than the Alpha series. They can provide high air flow with a small pressure drop. Their productivity is up to 2050 m3/h, and the excess pressure is up to 670 mBar.
For deep ponds or small containers would be better suited Beta series, which provides a high pressure drop of up to 1040 mbar with a low productivity of up to 170 m 3 / h.
For industrial applications, such as wastewater treatment plants, or large fisheries, you need powerful blower for water aeration of the Gamma series. It provides a large air flow of up to 750 m 3 /h at an excess pressure of up to 1020 mBar.
Busch Samos
High-performance German blowers, which are often used for aerating water in large reservoirs and wastewater treatment plants. Their productivity is up to 2640 m 3 /h, and the pressure drop in compressor mode is up to 500 mBar.
Advantages of Busch superchargers:
- Energy-saving motors are used, which reduces power consumption. This is especially true for industrial treatment facilities, since aeration requires high energy consumption.
- The quality of 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
SEKO economy class 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 with a pressure drop of up to 650 mBar, and have a number of advantages:
- Equipped with bipolar electric motors, which allow long-term operation without interruption.
- A wide range of models 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 vibrations, thanks to built-in silencers and lack of imbalance.
FPZ SCL
Italian high-pressure blowers FPZ SCL create a maximum pressure drop 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 wastewater 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 high efficiency Italian Bonora Motori electric motors.
- Provides even greater energy savings frequency regulation up to 70 Hz, which allows you to fine-tune performance according to specified parameters.
- Long-term operation is possible thanks to built-in motor overheating protection.
Becker SV
Another brand of vortex gas blowers that are produced and assembled in Germany. They create a pressure drop of up to 865 mbar and provide a continuous air flow with a capacity of up to 1050 m 3 / h and a power of up to 15 kW.
Becker blowers are used for aeration - to purify and oxygenate water in fish ponds and wastewater treatment plant tanks, and although their price is higher than, for example, VARP or SEKO, they have gained 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 service life - at least three years of continuous operation.
- The use of a built-in rotor speed control system increases efficiency, increases service life and allows performance to be adjusted to the optimal value for each specific task.
Rotary blowers for aeration
A vortex blower is not the only blower suitable for water aeration - for a large-volume aeration tank it makes sense to buy a high-performance Roots gas blower.
Our catalog presents 2 options for rotary blowers:
- VARP Altair provide gas flow with a capacity of up to 7548 m 3 /h and an excess pressure of up to 980 mBar.
- LUTOS DT operate with a capacity of up to 9771 m 3 /h and create a pressure drop of up to 1000 mbar.
These machines outperform vortex machines, but are more expensive. They have all the properties required for aeration installations in wastewater treatment plants:
- Environmental friendliness: they do not pollute the discharge gas with oil vapor, since the flow part is reliably isolated from the oil crankcase by a dynamic labyrinth seal.
- Low noise and vibration levels.
- High efficiency.
- Reliability and stable operation.
- Operating life of at least 100 thousand hours.
- The rotors are carefully balanced, allowing them to rotate at high speeds and provide high performance in a small size.
- Can work for a long time without breaks.
Blowers for wastewater aeration
Blowers for aeration are presented in a wide range of standard 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, required quantity 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 power consumed by sewage treatment plants. This is a very energy-intensive process, so electric blowers for aeration are selected based on optimal operating conditions.
How is wastewater treated?
There are many options for wastewater treatment systems. Blowers are used in aerobic cleaning systems to provide oxygen to the aerobic bacteria that process organic contaminants. To understand how the purification process occurs, let’s consider a biopurification system with a membrane unit.
Rice. 3. System biological treatment waste water with membrane block
First, wastewater enters the device mechanical cleaning, for example, sand traps or special nets.
After this, they enter the homogenizer, in which the wastewater is actively mixed with different composition, and then are moved by liquid pumps to the biotreatment system. This system consists of a denitrifier and an aeration tank-nitrifier.
The denitrifier is set to anoxic mode - there is no dissolved oxygen in the water, but there is chemically bound oxygen in the form of nitrites and nitrates. Organic pollutants contained in wastewater are oxidized by activated sludge (AS) to gaseous oxides and molecular nitrogen. To prevent sludge from settling at the bottom, a stirrer is installed in the anoxic 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 tank rectangular section, made of concrete with a waterproofing coating through which wastewater passes. The contaminated liquid is constantly mixed with activated sludge (colonies of beneficial aerobic microorganisms, bacteria and protozoa), and an air flow is forced into the container. It saturates water with oxygen, providing vital functions beneficial microorganisms, and also maintains sludge in suspension. Compressors or blowers supply compressed air through the water column to saturate it with oxygen through fine-bubble aerators that are 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 that are 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 should be 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-porous membranes is installed in the aeration tank-nitrifier, in which separation occurs clean water and AI.
Filtered water (permeate) is pumped into a container with clean water, from where it is transferred to an ultraviolet disinfection system, after which it is supplied to the consumer.
The separated activated sludge from the nitrifier is pumped into the denitrifier. To remove phosphorus, a ferric chloride solution is supplied to the moving AI stream. Thanks to the circulation of AI, its concentration is maintained in the biological treatment zone.
Calculation of a blower for aeration (aeration tank). How to define productivity?
The aeration process occurs in the aerobic zone, so we are actually solving the problem of how to choose a blower for an aeration tank.
Water from sewage flows into aeration tanks, where it must be saturated with a sufficient amount of oxygen to oxidize organic substances.
Consequently, you can select 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 flow rate, you can 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 wastewater),
h , m - working depth of the aeration tank - the depth to which the aerator is immersed;
L a , kg/m 3 - BOD of wastewater that is supplied to the aeration tank (0.002..0.003 kg/m 3 for the system discussed above);
k , kg/m 4 - air utilization coefficient, which depends on the ratio of the areas of the aerators and 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 a more efficient porous plate system, it is 2 times greater than 0.012 kg/m 4 .
The air flow that the supercharger must supply to the aeration tank is equal to:
Q =q a eration Q w(m 3 / h),
Where Q w, m 3 / h - average daily wastewater flow. If this parameter is not known to you, then to a first approximation it can be estimated by knowing the working volume of the aeration tank V slave / t 1 hour = Q w(m 3 / h).
Flow size Q and the performance of the blowers will be determined. To provide a given flow, several blowers with a capacity of Q i, working in parallel.
How to choose a blower for aeration tanks based on pressure?
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 selected so that this value does not exceed 30..35 mBar. Δ p a- pressure losses in aerators, which depend on the specific model and are given in the attached technical documentation, about 15..30 mbar);
p g =ρgh - pressure of the water layer in the aeration tank, where ρ - liquid density, g - acceleration of gravity.
Most often, the depth of aeration tanks is from 1 to 7 m, therefore, the required excess pressure is 100..800 mBar, which fits well into the pressure range created by vortex and rotary gas blowers.
Knowing the performance values Q i and pressure p , you can select blowers for water aeration according to the operating point using the calculator on the page
Yu.V. Gornev (General Director of Vistaros LLC)
It is a well-known fact that from 60 to 75 percent of the energy consumption of sewage treatment plants (STPs) of cities and large industrial enterprises comes from supplying air to the aeration system. This article discusses the issues of possible savings in energy consumption in the aeration system through the use of energy-efficient elements of the system.
The reserves for saving energy consumption in the WWTP aeration system are enormous; they can be 70% or more. Let's consider the main elements of this system that significantly affect energy consumption. If we omit such issues as the need to maintain air supply pipelines, etc., in good working condition, then these include:
- Availability of primary settling tanks at WWTPs, which allow reducing the Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) of wastewater at the inlet of aeration tanks. As a rule, primary settling tanks are already present at most large WWTPs.
- Introduction of the nitrification-denitrification process, which allows increasing the amount of dissolved oxygen in the return activated sludge. This process is increasingly being introduced during the construction and reconstruction of WWTPs.
- Timely maintenance and replacement of aerators.
- Application of controllable blowers optimal power, implementation unified system controls for all blowers.
- The use of specialized controlled valves in the air distribution system for aeration tanks.
- Introduction of a control system for each valve and all valves based on data from dissolved oxygen sensors installed in aeration basins.
- Application of air flow meters to stabilize the air distribution process and optimize the minimum dissolved oxygen level setting for the valve control system.
- Introduction into the control system of additional feedback from the ammonium sensor at the outlet of aeration tanks (used in certain cases).
The first two points (primary settling tanks and the introduction of nitrification-denitrification) relate largely to issues of capital construction at WWTPs and are not discussed in detail in this article. Below we discuss the implementation of modern high-tech modules and systems that make it possible to achieve a significant reduction in electricity consumption at WWTPs. These modules and systems can be implemented both in parallel with the solution of the first two points, and independently of them.
The main consumer of electricity in the aeration air supply system is the blowers. Their right choice is the basis of energy saving. Without this, all other elements of the system will not give the desired effect. However, we will not start with blowers, but will follow the order in which it is necessary to select all modules.
Aerators
One of the main characteristics of aerators is the specific oxygen dissolution efficiency, measured as a percentage per meter of immersion depth of the aerators. For modern new aerators this value is 6% and even 9%; for old aerators it can be 2% or lower. The design of aerators and the materials used determine their service life without loss of efficiency, which for modern systems ranges from 6 to 10 years or more. The choice of design, number and location of aerators is carried out according to such parameters as BOD and COD of wastewater at the entrance to the aeration system, the volume of incoming wastewater per unit time and the design of aeration tanks. If we are dealing with the reconstruction of a WWTP with very old aerators that are in poor condition, then, in some cases, only replacing the aerators and installing blowers corresponding to the new aerators will reduce energy consumption by 60-70%!
Blowers
As mentioned above, blowers are the main element that ensures savings in energy consumption. All other elements reduce the need for air supply or reduce resistance to air flow. But if you leave the old uncontrolled blower with low efficiency, there will be no savings. If several uncontrolled blowers are used in an aeration station, then, theoretically, by optimizing other elements of the system and achieving a reduction in air supply requirements, it is possible to decommission and transfer to reserve several blowers from those previously used and, thus, achieve a reduction in energy consumption. You can also try to compensate for daily fluctuations in the aeration system's oxygen demand by simply turning the backup blower on or off.
However, much more effective is the use of a controlled blower, or more precisely, a block of several controlled compressors. This makes it possible to provide air supply in exact accordance with demand, which varies significantly throughout the day, and also varies depending on the season and other factors. The usual constant supply of air by uncontrolled blowers is always excessive and leads to excessive energy consumption, and in some cases to disruption of the nitrification-denitrification process due to excess oxygen in the aeration tanks. At the same time, the lack of air supply leads to pollutants in the wastewater outlet of the WWTP exceeding the maximum permissible concentrations (MAC), which is unacceptable.
Precise control of the air supply with constant monitoring of the level of dissolved oxygen in the aeration tanks (and in some cases with constant automatic control of the concentration of ammonium and other pollutants in the effluent at the outlet of the aeration tanks) ensures an optimal level of energy consumption while ensuring compliance of the treated effluent with existing standards.
The need for several blowers in a unit (for example, two large and two small) is due to the fact that the control range air compressor very limited. It ranges, at best, from 35% to 100% power, more often from 45% to 100%. Therefore, one controlled blower cannot always provide optimal air supply, taking into account daily and seasonal changes in demand. Today, the most famous are three types of blowers: rotary, screw and turbo.
The choice of the required type of blower is made mainly by the following parameters:
- maximum and nominal air supply demand - depends on the parameters of the installed aerators, which in turn are selected based on their efficiency and the need of the entire aeration system for dissolved oxygen, as described above;
- the required maximum excess pressure at the outlet of the blower is determined by the maximum possible depth of the aeration basin drains, more precisely the depth of the aerators, as well as pressure losses when air passes through the pipeline and through all elements of the system, such as valves, etc.
As a rule, each controlled blower has its own control unit, it is also important to have common block control of all blowers, ensuring optimal operation. In most cases, control is carried out based on the pressure at the outlet of the blower unit.
Controlled air valves
If the system has one blower (or bank of blowers) supplying air to only one aeration basin, then it can be operated without air valves. But, as a rule, at aeration stations, a blower unit supplies air to several aeration tanks. In this case, air valves are required at the inlet of each aeration tank to regulate the distribution of air flow. Additionally, valves can be used on pipes that distribute the air supply to different zones one aeration tank. Previously, manually controlled butterfly valves were used for these purposes. However for effective management The aeration system must use remote controlled valves.
Important characteristics of controlled valves include:
- Linearity of the control characteristic, i.e. the degree of compliance of changes in the position of the valve drive (actuator) with changes in air flow through the valve throughout the entire control range.
- Error and repeatability of the valve drive working out the specified air flow setting. Determined by the quality of the valve (linearity of the control characteristic), actuator and actuator control system.
- Pressure drop across the valve in the operating range of opening.
The pressure drop across butterfly valves when partially opened can be quite significant and reach 160-190 mbar, which leads to large additional energy costs.
If the system uses even the highest quality, but universal valves (designed for both water and air), the pressure drop across such valves in the operating opening range (40-70%) is usually 60-90 mbar. Simply replacing such a valve with a specialized air valve VACOMASS elliptic will lead to additional savings of at least 10% in energy! This is due to the fact that the pressure drop across the VACOMASS elliptic over the entire operating range does not exceed 10-12 mbar. An even greater effect can be achieved when using VACOMASS jet valves for which the pressure drop in the operating range does not exceed 5-6 mbar.
Controlled dedicated air valves
VACOMASScompaniesBinder GmbH, Germany.
Often, at the installation site of the controlled valve, the pipeline is narrowed in order to use a valve of the optimal size. Since the contraction and expansion are carried out in the form of a Venturi tube, this does not lead to any significant additional pressure drop in the valve area. At the same time, the valve of smaller diameter operates in optimal range opening, which ensures linear control and minimizes the pressure drop across the valve itself.
Dissolved oxygen sensors and valve control system
BA1 – aeration pool 1; BA2 – aeration pool 2;
PLC – program logic controller;
BV – blower block;
F – air flow meter; P – pressure sensor;
O2 – dissolved oxygen sensor
M – drive (actuator) air valve
CPS – valve control system
SUV – blower control system
The figure shows the most common scheme for controlling the air supply process for several aeration basins. The quality of wastewater treatment in aeration tanks is determined by the presence required quantity dissolved oxygen. Therefore, the main controlled value is usually taken to be the concentration of dissolved oxygen [mg/liter]. One or more dissolved oxygen sensors are installed in each aeration tank. The control system sets a setpoint (set average value) for the oxygen concentration, so that the minimum actual oxygen concentration is guaranteed to provide a low concentration harmful substances(for example, ammonium) in the effluent at the exit of the aeration system - within the MPC. If the incoming volume of wastewater into a particular aeration tank decreases (or its BOD and COD decreases), then the need for oxygen also decreases. Accordingly, the amount of dissolved oxygen in the aeration tank becomes higher than the set point and, based on a signal from the oxygen sensor, the valve control system (VCS) reduces the opening of the corresponding air valve, which leads to a decrease in the air supply to the aeration tank. At the same time, this leads to an increase in pressure P at the outlet of the blower unit. The signal from the pressure sensor is sent to the blower control system (BCS), which reduces the air supply. As a result, the energy consumption of the blowers is reduced.
It should be noted that to solve the problem of energy saving, a well-thought-out optimal setting for a given minimum concentration of dissolved oxygen in the control system is very important.
Equally important is the correct and justified setting of the specified pressure P at the outlet of the blower unit.
Air flow meters
The main task of air flow meters in an aeration system from the point of view of energy saving is to stabilize the air supply process, which makes it possible to lower the dissolved oxygen concentration setting for the control system.
The air supply system from the blower unit to several aeration tanks is quite complex from a control point of view. In it, as in any pneumatic system, there is mutual influence and delay in the processing of control actions and signals from feedback sensors. Therefore, the actual dissolved oxygen concentration constantly fluctuates around the set point (set point). Availability of air flow meters and common system control of all valves can significantly reduce system response time and reduce fluctuations. Which, in turn, allows you to lower the setpoint without fear of exceeding the maximum permissible concentration of ammonium and other harmful substances in the wastewater at the outlet of the WWTP. From the experience of Binder GmbH, introducing data from flow meters into the control system allows additional energy savings of about 10%.
In addition, if the WWTP is undergoing a phased reconstruction of the aeration system, in which they first install aerators, valves, a valve control system and air flow meters while maintaining the old blower, and then move on to selecting new controlled blowers, then data on the actual air flow will help produce optimal choice blowers, which leads to significant savings during their purchase and operation.
A distinctive feature of VACOMASS flowmeters from Binder GmbH is their ability to work on short straight sections “before” and “after” due to special technological solutions, and also be installed directly in the VACOMASS valve block.
Ammonium sensor
An ammonium concentration sensor can be installed in the channel at the outlet of the wastewater from the aeration tank system to control the quality of treatment. In addition, the introduction of readings from the ammonium sensor into the control system allows you to further stabilize the system and obtain additional energy savings by further reducing the dissolved oxygen concentration set point.
An example of organizing a control system for air supply to aeration tanks with feedback by dissolved oxygen sensor (DO) and ammonium (NH4).
Aeration systems, which are equipped with industrial and local treatment plants, are designed to artificially enrich wastewater with oxygen, which oxidizes iron compounds and other impurities. For this purpose, special vacuum equipment is used that meets certain standards and requirements. In particular, treatment plants install aeration blowers of various capacities, making the cleaning process efficient and environmentally friendly. The Megatechnika MSK company is ready to supply interested enterprises with equipment with the parameters you need on favorable terms.
Basic requirements influencing the choice of blowers for water aeration
Natural aeration of water - an indispensable condition for the reproduction of aerobic bacteria that purify water, in nature this occurs continuously. However, an intensive, forced aeration system requires much larger volumes of air, for which a rotary or rotary water aeration blower is used. turbine type, meeting such parameters as:
- the ability to supply dry air, free of microparticles of lubricant, wear products or other harmful impurities, around the clock;
- maximum quiet operation;
- nominal productivity corresponding to the volume of processed waste;
- resistance to corrosion, temperature changes and precipitation;
- simplicity and simplicity in maintenance, operation, durability, reliability and energy efficiency of the design.
What types of blowers are there for aerating wastewater treatment plants?
There are submersible blowers that do not require additional systems cooling, and centrifugal, with multi-stage compression. For small treatment facilities, we recommend equipment that forces air into the pneumatic system using a screw unit. The operating principle of the compression chamber of rotary blowers eliminates the possibility of contact of oils with air, and the compressors themselves are characterized by a particularly low level of noise and vibration, efficiency and compactness, which is important when locating treatment plants near residential areas. For purification complexes of large industrial enterprises, compressors that compress air by moving pistons are more suitable.
We will find the most effective solution for you!
Moscow company "Megatechnika MSK" in large assortment offers 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 consequence, differences 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 global and Russian markets. All you need to do is submit an application online, and our experts will contact you to clarify the details.
