Wastewater treatment, Industrial wastewater treatment package
The most important environmental polluting industries are food industry (including dairy industry, meat products industry, etc.), steel industry, paper and cardboard industry, textile industry, glass industry, oil and gas and petrochemical industries and other industries. Appeared.
Industrial wastewater treatment methods
1) Physical methods
The methods by which the forces and physical properties of materials are used to remove them are called physical methods. Contamination, granulation, chemical precipitation, filtration and sedimentation are examples of physical methods of wastewater treatment.
The dust collector prevents the entry of sand and coarse particles into the treatment units. The use of garbage collection equipment to prevent the entry of any debris and large solids into the treatment plant units, a very useful and effective method in the physical protection of pumps and other mechanical equipment such as aerators, stirrers and pipes against possible damage and clogging. is.
Garbage collectors are usually made of nets or bar networks and are installed in the sewer flow path to prevent any large pieces of objects and garbage from entering the treatment ponds. Garbage collectors are divided into two types, small and large, in terms of the distance of the sieve bars. How to clean the garbage nets is possible by both mechanical and manual methods. In mechanical types, the garbage nets are cleaned with an automatic mechanism by cleaning rake arms or various other methods such as water spraying. Containers are designed and manufactured according to the order and according to the dimensions of the flow channel or based on the flow of water.
2) Chemical methods:
The methods in which chemical substances and reactions are used to remove contaminants are called. Aeration, coagulation and flocculation, ion exchange, pH adjustment are considered as chemical methods.
3) Biological methods:
This method uses biological processes to remove contaminants. Biological methods can be divided into two general categories:
a. Aerobic methods:
Some biological processes take place in the presence of dissolved oxygen, which are called aerobic processes, and the methods that use aerobic processes are called aerobic biological methods. Activated sludge method, wide aeration activated sludge method, RBC, SBR, MBR are examples of aerobic biological methods.
B. Anaerobic methods:
The processes that take place in the absence of dissolved oxygen by microorganisms are called anaerobic processes. These processes are used in biological methods of wastewater treatment. UASB, FBR, ASBR methods are examples of anaerobic wastewater treatment methods. It should be noted that biological anaerobic processes are predominant in septic tanks due to lack of sufficient dissolved oxygen.
A variety of biological methods of industrial wastewater treatment
1) Activated sludge method
In deep aeration methods, in order to properly transfer and inject compressed air into water or wastewater, the use of air distribution diffusers is recommended due to the production of very small bubbles. Are available. The smaller the air bubbles, the higher the efficiency of oxygen transfer to the water.
The micro-bubble diffusers include a disc with a polypropylene retaining frame and a flexible rubber membrane made of EPDM for the passage of air bubbles. Made of polyethylene can be installed on all types of pipes. In many cases, due to the need for mixing and turbulence in the sewage balancing ponds and also to prevent air pressure drop and less possibility of clogging the holes, the use of large bubble diffusers is preferred. .
These diffusers have the ability to mix better and suspend sediments and thick sludge. Large bubble diffusers are often made of polypropylene and PVC in the form of simple plates, valves and cones.
The average aeration capacity of diffusers is about 5 to 15 cubic meters per hour and the bubbles produced are in the size of 1 to 5 mm.
2) SBR method (Sequencing Batch Reactor)
When the inflow of wastewater into the treatment system is very low, considering aeration and sedimentation units separately will increase the cost of treatment per cubic meter of wastewater. In such cases, by making a change in the activated sludge method, this method is adapted for use in the treatment system. During this change, it combines aeration and sedimentation tanks with each other and performs aeration and sedimentation processes alternately and in consecutive times.
3) RBC method - (ARotating Biological Contactor)
In all activated sludge-based methods, the growth of microorganisms is suspended and some energy is expended on aeration. In situations where the cost of energy supply is very high, energy consumption can be reduced using the RBC method. Because in this method, microorganisms stick to the surface of revolving and semi-submerged plates in sewage and grow on them.
4) MBR method - (Membrane Biological Reactors)
Today, one of the most advanced methods of wastewater treatment is the membrane method (MBR), in which the separation of microbes is done by the membrane. By installing these membranes inside the biological reactor, there is no need for sedimentation and filtration sections, and these same membranes perform the task of separating the treated wastewater from the sludge. The use of membranes makes the space Low, high efficiency wastewater treatment should be done so that the quality of treated wastewater is better than wastewater standards for discharge to surface water.
In wastewater treatment, bioreactor membranes (MBR) is a new technology that combines traditional activated sludge treatment with modern membrane separation technology. Due to the strong separation properties of membranes, activated sludge and organic matter with large molecules can be collected in the MBR tank and clean water can be filtered by passing through the membranes. MBR, bioreactor and water filtration processes can be performed simultaneously. No reservoir is required for sedimented sludge. In this method, the concentration of sludge is much higher than the traditional method. Reservoir residence time (HRT) and reservoir sludge residence time (SRT) can be controlled separately. In the MBR method, not only ordinary wastewater but also many contaminated wastewaters with large amounts of organic matter can be treated. Many wastewaters can be easily treated using MBR technology.
Due to its membrane separation properties, the bio-reactor performance has been greatly enhanced by the MBR. This method has advantages compared to the traditional wastewater treatment method, such as more efficient bio-reactor performance, good resistance to pressure and impact caused by the effluent, high quality of the effluent, small size of the wastewater treatment plant, longevity Much sludge, as well as the fact that the MBR system can be controlled automatically by the PLC. In other words, due to the separation properties of the membranes, the effluent is of good quality, so that it can be reused without any problems.
Advantages of MBR
1. Provides excellent separation. MBR effluent is of high quality, so that it can be reused directly. (SS <0.5mg / L, NTU <0.2)
2. Membranes can collect all microorganisms in bulk in the MBR tank, so that the residence time of wastewater in the tank (HRT) can be easily controlled. The MBR method is suitable for different wastewaters with different COD and BOD.
3. The high concentration of sludge in the MBR reservoir is 2 to 3 times higher than the traditional method. MBR is a perfect way to condense wastewater.
4. MBR can remove NH3.N and P well.
5. Long sludge life (SRT). Complex organic matter can be degraded. In this case, the sludge becomes balanced.
6. MBR system can be controlled by PLC. This type of exploitation is done automatically.
7. MBR can be designed as a complete and mobile set, as it only needs a very small area.
1- Temperature: 5 to 45 degrees Celsius, pH between 2 to 10
2. Air to water ratio: 20 to 1 to 30 to 1
3- Operating pressure: less than 0.02 MPa, 10 t / m3 / h
4- MBR capacity: 1 to 60 m / hr
Scope of application
1. High concentration sewage
2- Wastewater from food, livestock and slaughterhouse industries
3- Wastewater from beverage and wine factories
4- Wastewater from paint, leather and paper factories
5. Reuse of water from washing machines
6. Wastewater with high concentration of organic matter, such as wastewater from pharmaceutical factories
7. Deformation of old sewage facilities
8. Small water treatment plant
9- Reuse of water from municipal sewage
5) MBBR method (Moving Bed Biofilm Reactors)
The MBBR system uses acne (Packing) that floats in the aeration tank. A biofilm, or microbial layer, grows on submerged acne, increasing the biological mass that floats in the wastewater, which acts as a decomposer of organic matter. This method is very desirable for removing BOD, COD and nitrogen.
In recent years, the use of packing media has been expanding day by day due to its high contact area with low volume and as a result of increasing the efficiency of wastewater treatment, especially in biological methods of adhesion growth. These packings are produced from the best materials and mainly in the form of light blocks with a very durable structure in various designs in the form of honeycombs and egg combs with vertical, cross and diagonal channels.
Application and consumables of media packages are:
Contact bed in gasification towers
-As a current ripple in sedimentation and degreasing tanks
- As a filler bed for wastewater treatment reactors
- Heat exchange bed in cooling towers
Advantages of plastic packing:
- High specific surface area per unit volume
- High resistance to UV rays and corrosion agents
-Light weight, high strength, ease of transportation
The use of adhesive growth process in aerobic and anaerobic systems by stabilizing microorganisms on packing and biofilm formation increases the mass of biomass in the form of adhesive and suspended, while increasing bioremediation reduces the required volume of treatment.
In the improvement of aerobic systems, by installing Biofix media (advanced research), the capacity of the refinery can be increased several times, or the refineries that have problems can be upgraded and optimized. In anaerobic bioreactors such as UASB, by installing biofix media (advanced research) in part or all of the reactor volume, in addition to increasing the capacity, the bioreactor can be made resistant to organic, hydraulic, chemical and thermal shocks and sludge escape. Prevented. It is clear to everyone that if the sludge escapes from anaerobic reactors due to the low growth rate (yield) of anaerobic microorganisms, it will take months.
Return to the original desired state.
Applications of this media packing are increasing the capacity of existing treatment plants, optimizing working bioreactors and making them resistant to organic-thermal and hydraulic shocks, removing nitrate from drinking water biologically, removing ammonia from fish farms and increasing its capacity. , Liquid and gas contact towers, degassing towers and cooling towers and many more
Advantages: Packing Media Packing Media
1. The most advanced media produced in the world
2. It is designed in such a way that the parts are assembled to each other and to any volume.
3. The whole bed is available equally.
4. There is no dead space.
5. There is no problem with clogging and does not need backwash.
6. The stream has no chance of being channeled at all
7. Suitable for all aerobic and anaerobic processes.
8. Has a very high contact level.
6) IFAS method (Integrated Fixed Film Activated Sludge)
This method is a combination of activated sludge process and MBBR process. For this reason, both "fixed bed" and activated sludge methods have advantages.
By combining activated sludge with very high flexibility and a stable bed with high resistance to organic and biological load shock, a very high efficiency can be provided for this system.