CN102167469A - Fluidized bed film bioreactor for sewage treatment - Google Patents

Abstract

A fluidized bed membrane bioreactor belongs to the technical field of water and waste water treatment. The present invention utilizes the process of combining a biological fluidized bed and a membrane bioreactor, that is, the reactor is filled with carrier particles with a diameter of about 5mm made by waste rubber powder, activated carbon and adhesive, and the filling ratio is 10% of the effective volume of the reactor. %-30%. Relying on the synergistic effect of the carrier and the sludge, the film hanging is completed, and the microorganisms grow on the filler, which reduces the sludge concentration in the reactor, changes the environmental operating conditions of the reactor, and slows down the membrane fouling, thereby prolonging the service life of the membrane and improving the efficiency of the membrane. processing capacity. The present invention fills the membrane bioreactor with self-made carrier particles, and uses the filler to change the internal microenvironment of the fluidized bed membrane bioreactor and regulate it, such as the amount of dissolved oxygen (DO), filler and hydraulic retention Time is adjusted to form a local anoxic zone, and then realize the simultaneous nitrification and denitrification denitrification function, improve the removal efficiency of total nitrogen and improve the efficiency of denitrification. The invention has the advantages of simple structure, no need to add chemicals, simple operation, high efficiency, good effluent quality, energy saving, and can remove various pollutants such as organic matter and total nitrogen at the same time, and is suitable for the treatment of organic waste water such as industrial and domestic waste water. It is expected to be used in engineering practice.

Description

A fluidized bed membrane bioreactor for sewage treatment

technical field

The invention belongs to the technical field of membrane bioreactor and water treatment, and in particular relates to a water treatment process and equipment for removing organic matter and total nitrogen in sewage by using a fluidized bed membrane bioreactor.

Background technique

Membrane bioreactor is a sewage treatment system and recycling process that combines high-efficiency membrane separation technology and biodegradation of activated sludge. The membrane module replaces the secondary sedimentation tank in traditional biological treatment technology. Membrane bioreactor has the advantages of good solid-liquid separation effect, good effluent quality, small amount of sludge production, small footprint, and simple operation and management. Membrane bioreactor has become a hot spot in the field of water treatment at home and abroad because of its outstanding advantages that cannot be compared with the traditional activated sludge method. At home and abroad, there have already been considerable scale and number of membrane bioreactor sewage treatment and recycling projects.

Sludge concentration is an important parameter of the membrane bioreactor system. The importance of the membrane bioreactor is to use the high concentration of the separation of the membrane to increase the sludge concentration of the membrane bioreactor, thereby increasing the organic matter removal capacity of the bioreactor, but relatively High sludge concentrations negatively affect membrane flux. Under certain conditions, the higher the sludge concentration, the more sludge will adhere to the membrane surface, the speed of forming a filter cake layer will be accelerated, the membrane flux will decrease, membrane fouling will inevitably occur, and the cleaning frequency will increase, resulting in operating costs. The life of the membrane is shortened, and it also brings great inconvenience to the operation and management. Membrane fouling has become a "bottleneck" restricting the application and development of this process.

Biological denitrification technology has the characteristics of low investment, small footprint, and no secondary pollution, and is recognized as one of the most promising methods. Biological nitrogen removal technology first converts ammonia nitrogen into nitrate nitrogen through microbial nitrification, and then converts nitrate nitrogen into nitrogen gas into the atmosphere through denitrification, and finally realizes the cycle of nitrogen elements and the harmlessness of ammonia nitrogen.

The traditional nitrification and denitrification process includes two stages of nitrification and denitrification, which are completed by nitrifying bacteria and denitrifying bacteria respectively. Due to the different requirements of the two on the environment, these two processes generally cannot occur at the same time, but can only be carried out sequentially, that is, The nitrification reaction is completed by autotrophic bacteria under aerobic conditions, and the denitrification reaction is completed by heterotrophic bacteria under anaerobic/anoxic conditions. In recent decades, despite the great development of biological denitrification technology, nitrification and denitrification are still carried out in independent or separated reactors with different dissolved oxygen (DO) concentrations, or in time or space On the other hand, the alternating anoxic and aerobic environments are carried out in one reactor at the same time, and one process is divided into two systems, the condition control is complex, the two are difficult to unify in time and space, the denitrification effect is poor, the equipment is huge, and the investment is high. Obviously, if the two nitrification and denitrification processes can be carried out in the same reactor, more space can be saved, and the two processes of oxidation of nitrite to nitrate and reduction to nitrite can be avoided. The redundant reaction can save oxygen and organic carbon, which will greatly simplify the process of biological denitrification, improve the efficiency of biological denitrification, and save investment.

Contents of the invention

The inventor's long-term research shows that the properties of the mixed liquid in the membrane bioreactor have a great influence on the membrane fouling, and the important influencing factors include the concentration of dissolved organic matter in the mixed liquid, the concentration of colloid and the concentration of sludge. When the organic load of the membrane bioreactor is high or after a long period of operation, the concentration of the mixed solution and the concentration of organic substances are too high, and the membrane fouling will be aggravated. In order to improve the properties of the mixed liquid in the membrane bioreactor, control the development rate of membrane fouling, stabilize the operation of the membrane bioreactor, and reduce the operating cost of the membrane bioreactor, the invention provides a fluidized bed membrane bioreactor is Sewage treatment and reuse process of the combined process of biological fluidized bed and membrane bioreactor. The mixed liquid in the mixed liquid is effectively treated to improve the properties of the mixed liquid so as to control membrane fouling.

The main content of this technology is: filling the membrane bioreactor with self-made filler, under the action of water flow, relying on the synergistic effect of the carrier and sludge, free bacteria, microorganisms and organic matter in the water hang on the concave surface of the filler to complete the hanging film, and the microbial Under the action of metabolism, the organic matter is degraded and removed; because the membrane module has a good solid-liquid separation effect, all activated sludge and fillers can be trapped in the membrane bioreactor, which ensures the continuous and stable removal effect of the system on organic matter and greatly prolongs the life of the system. The operating cycle of the membrane module is shortened. In addition, due to the film hanging of the filler, the concentration of the sludge in the mixed solution is reduced, and the cleaning frequency of the membrane module is also slowed down.

The invention fills the membrane bioreactor with self-made carrier particles, and uses the filler to change the internal microenvironment of the fluidized bed membrane bioreactor and regulate it, such as the amount of dissolved oxygen (DO), filler and hydraulic retention Time is adjusted to form a local anoxic zone, and then realize the simultaneous nitrification and denitrification denitrification function, improve the removal efficiency of total nitrogen and improve the efficiency of denitrification.

The technical scheme adopted in the present invention is:

The fluidized bed membrane bioreactor comprises a reactor system (4), a membrane module (5), a peristaltic pump (2) and (10) to control the influent flow and the effluent flow to adjust the hydraulic retention time (HRT). The reactor is filled with carrier particles with a diameter of about 5mm made by waste rubber powder, activated carbon and binder. The air enters the reactor through the air pump (8) through the flow meter (7) and then through the perforated aeration pipe (6). Oxygen required by activated sludge microorganisms. The liquid level in the reactor is controlled by a liquid level controller (3). The test inlet water is sent into the bioreactor by the inlet pump (2), and then the organic matters are removed through the catabolism of the microorganisms in the bioreactor, and finally the negative pressure water head H formed by the outlet pump (10) is pumped by the bioreactor. The hollow fiber membrane (5) is discharged.

The carrier particles are ellipsoidal elastic fillers with multiple pairs of holes, the filling ratio is 10%-30% of the effective volume of the reactor, the membrane in the membrane module is a hollow fiber membrane, the membrane pore size is 0.1um, and the surface area of the membrane is 0.2 m2. The flux is 5-50L/(m2 h)

The parameters of the fluidized bed membrane bioreactor are: hydraulic retention time 6-20h; operating temperature 10-30°C PH: 6-8; sludge retention time: 20-50d, dissolved oxygen concentration 0.5-3.0mg/L.

Fluidized bed membrane bioreactor of the present invention has following characteristics:

1. The treatment unit adopts a fluidized bed membrane bioreactor, which has the advantages of high volume load, low sludge output, no sludge bulking problem, good solid-liquid separation effect, and operation management.

2. The carrier is filled in the fluidized bed membrane bioreactor, and microorganisms grow on the carrier to reduce the sludge concentration in the membrane bioreactor. Thereby, membrane fouling is slowed down, the service life of the membrane is prolonged, and the processing capacity of the membrane is improved.

3. The air generated by the air pump enters the membrane bioreactor through the aeration device, which can wash the surface of the membrane filament to reduce pollution, and can also provide the oxygen required by the activated sludge microorganisms.

4. The membrane bioreactor is filled with self-made carrier particles and the internal microenvironment is regulated, such as the dissolved oxygen (D0), the amount of filler and the hydraulic retention time are regulated, so as to form a local anoxic zone, and then realize synchronous nitrification and denitrification The denitrification function improves the removal efficiency of total nitrogen and improves the efficiency of denitrification.

5. It has a simple structure, no need to add chemicals, small footprint, good effluent quality, energy saving, and can simultaneously remove organic matter, total nitrogen and other pollutants.

6. The fluidized bed membrane bioreactor in the present invention has strong impact resistance and is suitable for the treatment of various waste waters.

Description of drawings

Fig. 1 is a schematic flow chart of the fluidized bed membrane bioreactor reactor sewage treatment process of the present invention.

Figure 2 is a schematic diagram of the curtain membrane module used in the fluidized bed membrane bioreactor reactor

Figure 3 is a schematic diagram of the packing carrier used in the fluidized bed membrane bioreactor reactor

Reference signs: 1. Water inlet tank, 2. Water inlet pump, 3. Liquid level controller, 4. Transducer, 5. Membrane module, 6. Aeration pipe, 7. Flow meter, 8. Air pump, 9. Pressure Table, 10. Outlet pump

Detailed ways

Example 1

Figure 1 is a diagram of a fluidized bed membrane bioreactor device, including a reactor system (4), membrane modules (5), peristaltic pumps (2) and (10) to control the influent flow and effluent flow to adjust the hydraulic retention time (HRT ). The reactor is filled with carrier particles with a diameter of about 5mm made by waste rubber powder, activated carbon and binder. The air enters the reactor from the air pump (8) through the flow meter (7) and then through the perforated aeration pipe (6). The air volume is controlled by the flow meter, which can wash the surface of the membrane filament to reduce pollution, and can also provide the activated sludge microorganisms. oxygen. The liquid level in the reactor is controlled by a liquid level controller (3). The test inlet water is sent into the bioreactor by the inlet pump (2), and then the organic matters are removed through the catabolism of the microorganisms in the bioreactor, and finally the negative pressure water head H formed by the outlet pump (10) is pumped by the bioreactor. The hollow fiber membrane (5) is discharged.

The carrier particles are elliptical elastic fillers with multiple pairs of holes, the filling ratio is 10% of the effective volume of the reactor, the membrane in the membrane module is a hollow fiber membrane, the membrane pore diameter is 0.1 μm, and the surface area of the membrane is 0.2m2. The collected membrane flux is 10L/(m2·h).

The parameters of the fluidized bed membrane bioreactor are: hydraulic retention time 10h; operating temperature: 10-30°C PH: 6-8; gas volume 0.5m3/h, dissolved oxygen concentration 1-2mg/L. The system uses intermittent suction to discharge water, pumping for 12 minutes, and stopping for 3 minutes.

The simulated domestic sewage containing 300-600 mg/L of COD, 15-30 mg/L of NH3-N, and 3-6 mg/L of inorganic phosphorus enters the fluidized bed membrane bioreactor from the water inlet. Sludge discharge, the sludge concentration is 2000-7000mg/L. Effluent COD is 10-35mg/L, COD removal rate is 90%-98%; NH3-N is 0.5-7mg/L, NH3-N removal rate is 90%-98%; effluent total nitrogen is 5-12mg/L , The removal rate of total nitrogen is 63% to 75%. The quality of effluent water meets the standard of "Integrated Wastewater Discharge Standard".

Example 2

The difference from Example 1 is that the carrier particles are ellipsoidal elastic fillers with multiple pairs of holes, and the filling ratio is 20% of the effective volume of the reactor. The parameters of the fluidized bed membrane bioreactor are: hydraulic retention time 13h; operating temperature: 10-30°C; PH: 6-8; gas volume: 0.3m3/h, dissolved oxygen concentration: 0.2-2mg/L. The system uses intermittent suction to discharge water, pumping for 12 minutes, and stopping for 3 minutes. The membrane pore diameter is 0.2um, the surface area of the membrane is 0.2m2, and the membrane flux is 7.5L/(m2·h).

Example 3

The difference from Examples 1 and 2 is that the carrier particles are ellipsoidal elastic fillers with multiple pairs of holes, and the filling ratio is 30% of the effective volume of the reactor. The parameters of the fluidized bed membrane bioreactor are: hydraulic Residence time 10h; operating temperature: 10-30°C; PH: 6-8; gas volume: 0.5m3/h, dissolved oxygen concentration: 0.5-2.5mg/L. The system uses intermittent suction to discharge water, pumping for 12 minutes, and stopping for 3 minutes. The membrane pore diameter is 0.5um, the surface area of the membrane is 0.5m2, and the membrane flux is 10L/(m2·h).

Claims (6)

1. A fluidized bed membrane bioreactor fluidized bed membrane bioreactor, comprising reactor system (4), membrane module (5), peristaltic pump (2) and (10) control influent flow and effluent flow to Adjust the hydraulic retention time (HRT). The reactor is filled with carrier particles with a diameter of about 5mm made by waste rubber powder, activated carbon and binder. The air enters the reactor from the air pump (8) through the flow meter (7) and then through the perforated aeration pipe (6). The air volume is controlled by the flow meter, which can wash the surface of the membrane filament to reduce pollution, and can also provide the activated sludge microorganisms. of oxygen. The liquid level in the reactor is controlled by a liquid level controller (3). The test inlet water is sent into the bioreactor by the inlet pump (2), and then the organic matters are removed through the catabolism of the microorganisms in the bioreactor, and finally the negative pressure water head H formed by the outlet pump (10) is pumped by the bioreactor. The hollow fiber membrane (5) is discharged. 2. The fluidized bed membrane bioreactor as claimed in claim 1, characterized in that: the filling carrier particles in the reactor are ellipsoid elastic fillers which are many pairs of holes, made by waste rubber powder, gac and binding agent For carrier particles with a diameter of about 5mm, the filling ratio is 10%-30% of the effective volume of the reactor. 3. The fluidized bed membrane bioreactor according to claim 1, characterized in that: the lower part of the membrane module is equipped with an aeration pipe, which can wash the surface of the membrane filament to slow down pollution during operation, and can also provide activated sludge microorganisms Oxygen needed. 4. fluidized bed membrane bioreactor as claimed in claim 1, is characterized in that: rely on the synergism of carrier and sludge, finish hanging film, microorganism grows on the packing, has reduced sludge concentration in the reactor, changed The environmental operating conditions of the reactor and membrane fouling are slowed down, thereby prolonging the service life of the membrane and improving the processing capacity of the membrane. 5. fluidized bed membrane bioreactor as claimed in claim 1, is characterized in that: membrane bioreactor fills self-made carrier particle and internal microenvironment is regulated and controlled, as the amount of dissolved oxygen (DO), filler and The hydraulic retention time is regulated to form a local anoxic zone, thereby realizing the simultaneous nitrification and denitrification denitrification function, improving the removal efficiency of total nitrogen and improving the efficiency of denitrification. 6. The fluidized bed membrane bioreactor according to claim 1, characterized in that: simple structure, no need to add chemicals, small footprint, good effluent quality, energy saving, and can remove organic matter and total nitrogen at the same time and other pollutants.

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