A biological aerosol purification system and method with micro-nano bubble partition aeration

Abstract

The application discloses a kind of micro-nano bubble partitioned aeration biological aerosol purification system and method, including micro-nano bubble in-situ generation zone, micro-nano bubble transition zone and sludge-water coexistence reaction zone, biological aerosol purification system is configured in micro-nano bubble in-situ generation zone, micro-nano bubble is generated with the entering sewage by micro-nano bubble generating device, micro-nano bubble transition zone will micro-nano bubble transition form a large number of nanobubbles;Sludge is placed in sludge-water coexistence reaction zone, nanobubbles are fully contacted with activated sludge, and pollutant degradation is realized.The present application utilizes the characteristics of different stages of micro-nano bubble aeration process, solves the problems of sludge floating, microbial cell damage and high biological aerosol emission level, improves the efficiency of wastewater treatment and reduces the exposure risk.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sewage treatment and the field of aerosol purification, and in particular to a novel micro-nano bubble partitioned aeration biological aerosol purification system and method. BACKGROUND

[0002] In recent years, micro-nano bubbles have shown great application potential in the field of water treatment due to their high oxygen solubility efficiency, long residence time, and large specific surface area. However, through literature retrieval, it is found that when micro-nano bubble aeration technology is applied to traditional aeration tanks, there are still many limitations, as follows:

[0003] 1. Damages the activated sludge floc structure, causing sludge to float, and reducing the effluent water quality.

[0004] 2. Damages the microbial cells in the activated sludge, reducing the sewage treatment efficiency.

[0005] 3. A large amount of foam is generated at the air-water interface, causing a large amount of biological aerosols to be generated and dispersed, seriously polluting the surrounding air environment.

[0006] Therefore, there is an urgent need to provide a system and method that effectively avoids the emission of a large amount of biological aerosols, ensures the smooth operation of the treatment process, and improves the sewage treatment efficiency. SUMMARY

[0007] To solve the above-mentioned defects in the prior art, the purpose of the present application is to provide a micro-nano bubble partitioned aeration biological aerosol purification system and method, which effectively avoids the sludge floating phenomenon caused by a large amount of micro-bubbles existing in the micro-nano bubble in-situ generation stage by using partitioned micro-nano bubble generation, nano-bubble transition, and sludge-water coexistence reaction aeration, and improves the sludge settling performance.

[0008] The present application is realized by the following technical solutions.

[0009] In one aspect of the present application, a micro-nano bubble partitioned aeration biological aerosol purification system is provided, comprising:

[0010] A micro-nano bubble in-situ generation zone is configured with a biological aerosol purification system and a micro-nano bubble generating device, for generating micro-nano bubbles with the micro-nano bubble generating device and the entering sewage;

[0011] A micro-nano bubble transition zone is configured with a flow guide baffle, for transitioning the micro-nano bubbles to form a large amount of nano-bubbles;

[0012] A sludge-water coexistence reaction zone is configured with a stirring device, for fully contacting the nano-bubbles with the activated sludge placed in the sludge-water coexistence reaction zone, and realizing the degradation of pollutants.

[0013] As preferred, the micro-nano bubble in-situ generating area is provided with a biological aerosol purification system, a sealing cover plate is additionally arranged on the top of the micro-nano bubble in-situ generating area, and an aerosol collecting pipe is arranged on the sealing cover plate and inserted into the micro-nano bubble in-situ generating area. The sealing cover plate is a detachable movable cover plate, and a reserved hole is arranged on the sealing cover plate.

[0014] As preferred, the lower end of the aerosol collecting pipe is connected with a horn, and the horn is located above the liquid surface and close to the sealing cover plate.

[0015] As preferred, the aerosol collecting pipe is replaced with an ultraviolet lamp tube, which is installed below the sealing cover plate.

[0016] As preferred, the biological aerosol is transported to a subsequent aerosol treatment unit through the aerosol collecting pipe, and the subsequent aerosol treatment unit is replaced by a filter material, which is activated carbon adsorption or a loaded carrier filler.

[0017] As preferred, the micro-nano bubble in-situ generating area is provided with a biological aerosol purification system, which is a floating ball at the gas-liquid interface.

[0018] As preferred, the micro-nano bubble transition area is an open area, and flow guide baffles are arranged in the micro-nano bubble transition area in a staggered manner. The height of the flow guide baffles is consistent with the height of the frame of the micro-nano bubble transition area, and the width of the flow guide baffles is slightly shorter than the width of the frame of the micro-nano bubble transition area.

[0019] As preferred, the sludge-water coexistence reaction area is an open area, and the sludge-water coexistence reaction area is provided with a stirring device or an aeration device.

[0020] In another aspect of the present application, a biological aerosol purification method of the micro-nano bubble partition aeration of the purification system is provided, which comprises:

[0021] The sewage enters the micro-nano bubble in-situ generating area, the water temperature is controlled, the micro-nano bubbles are generated in the micro-nano bubble in-situ generating area through the micro-nano bubble generating device, the gas-water ratio, the air flow and the air pressure are controlled, and the micro-nano bubbles are generated;

[0022] A large amount of micro-nano bubbles enter the micro-nano bubble transition area with water, the water flow speed and the hydraulic retention time are controlled, and the micro-nano bubbles are converted into nano bubbles through the flow guide baffles;

[0023] The activated sludge is placed in the sludge-water coexistence reaction area, the nano bubbles enter the sludge-water coexistence reaction area, the mass ratio of the number of the nano bubbles to the activated sludge is controlled, the nano bubbles are fully contacted with the activated sludge under the action of the stirring device or the aeration device in the sludge-water coexistence reaction area, and the pollutant degradation is realized.

[0024] As preferred, the water inlet temperature is 15-35 DEG C, the gas-water volume ratio is 0.3-0.5:1, the air inlet flow is 50-70 mL / min, and the air inlet pressure is 0.3-0.5 MPa.

[0025] The water flow speed is 0.01-0.1 m / s, and the hydraulic retention time is 3-5 min.

[0026] The control aeration amount is 50-70 ml / min, and the aeration time is 20-30 min.

[0027] The present application has the following beneficial effects due to the above technical scheme:

[0028] 1. The micro-nano bubble partitioned aeration tank is divided into a micro-nano bubble in-situ generation zone, a micro-nano bubble transition zone and a sludge-water coexistence reaction zone, the micro-nano bubble in-situ generation zone and the micro-nano bubble transition zone only contain sewage and do not place activated sludge, the micro-nano bubbles are generated and converted in the zones, and the damage caused by the direct contact between a large amount of micro-bubbles and activated sludge is avoided. The sludge-water coexistence reaction zone is a region where sewage, activated sludge and nano-bubbles coexist, and the existence of a large amount of nano-bubbles improves oxygen utilization rate and sludge settling performance, thereby improving sewage treatment efficiency.

[0029] 2. The biological aerosol purification system is additionally arranged at the top of the micro-nano bubble in-situ generation zone, and biological aerosol generation and emission are simultaneously inhibited.

[0030] 3. The sludge settling performance is improved. In the micro-nano bubble in-situ generation zone, micro-nano bubbles are generated by controlling water inlet temperature, gas-water ratio, air inlet flow and air inlet pressure, and are converted into nano-bubbles by controlling water flow speed and hydraulic retention time, when the proportion of nano-bubbles increases to more than 50%, the influence of the micro-nano bubble aeration technology on the sludge settling performance becomes positive, oxygen utilization rate and sludge settling performance are improved, and thereby sewage treatment efficiency is improved. The partitioned aeration effectively avoids the sludge floating phenomenon caused by a large amount of micro-bubbles existing in the micro-nano bubble in-situ generation stage, and improves the sludge settling performance.

[0031] 4. The sludge activity is high. Nano-bubbles hardly cause damage to bacteria in activated sludge flocs, can improve the aerobic metabolism and growth of microorganisms, improve oxygen utilization efficiency, the present application only places activated sludge in the sludge-water coexistence reaction zone, effectively avoids the damage of a large amount of micro-bubbles to microbial cells, and improves the sludge activity.

[0032] 5. The exposure risk is low. The present application additionally arranges a biological aerosol purification system in the micro-nano bubble in-situ generation zone, effectively avoids the emission of a large amount of biological aerosols, and thereby reduces the exposure risk.

[0033] 6. The process runs more smoothly. In the present application, the micro-nano bubbles enter the sludge-water coexistence reaction zone after passing through the micro-nano bubble in-situ generation zone and the micro-nano bubble transition zone, which plays a role of pre-aeration. In addition, the stirring device is arranged to control the aeration conditions to ensure that the nano bubbles and the activated sludge are in full contact, which can ensure the smooth running of the treatment process and improve the efficiency of the sewage treatment. In addition, the partitioned aeration avoids the possibility of over-aeration of the micro-nano bubbles, thereby avoiding the occurrence of sludge disintegration and ensuring the smooth running of the activated sludge system. BRIEF DESCRIPTION OF DRAWINGS

[0034] The drawings described herein are used to provide further understanding of the present application, form a part of the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0035] Figure 1 is a schematic diagram of the present application;

[0036] Figure 2 is a schematic diagram of the aerosol collection tube of the present application;

[0037] Figure 3 is a schematic diagram of the filter material of the present application;

[0038] Figure 4 is a schematic diagram of the aeration device of the present application;

[0039] Figure 5 is a schematic diagram of the ultraviolet lamp tube of the present application;

[0040] Figure 6 is a schematic diagram of the floating ball at the gas-liquid interface of the present application;

[0041] Fig. 7(a), (b) is the dissolved oxygen charging condition under different air inlet pressures;

[0042] Figure 8 is the size distribution range of the micro-nano bubbles of the present application.

[0043] The reference signs are explained as follows:

[0044] 1-micro-nano bubble in-situ generation zone, 2-micro-nano bubble transition zone, 3-sludge-water coexistence reaction zone, 4-micro-nano bubble generation device, 5-sealing cover plate, 6-reserved orifice, 7-water inlet pipe, 8-aerosol collection tube, 801-horn mouth, 802-filter material, 9-first water outlet, 11-second water outlet, 10-flow guide baffle, 12-stirring device, 13-water outlet pipe, 14-aeration device, 15-ultraviolet lamp tube, 16-floating ball. DETAILED DESCRIPTION

[0045] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0046] Example 1:

[0047] like Figure 1 As shown in the figure, this embodiment provides a micro-nano bubble zoned aeration bioaerosol purification system, which divides the aeration tank into three parts: a micro-nano bubble in-situ generation zone 1, a micro-nano bubble transition zone 2, and a mud-water coexistence reaction zone 3, which are separated by partitions. A first outlet 9 is provided on the partition between the micro-nano bubble in-situ generation zone 1 and the micro-nano bubble transition zone 2, and a second outlet 11 is provided on the partition between the micro-nano bubble transition zone 2 and the mud-water coexistence reaction zone 3. The first outlet 9 and the second outlet 11 are located on both sides of the partition in the micro-nano bubble transition zone 2, arranged alternately. The first outlet 9 should be below the liquid surface and as close to the bottom as possible, while the second outlet 11 is distributed in the middle of the partition. Multiple first outlets 9 and second outlets 11 are distributed along the partition.

[0048] The micro-nano bubble in-situ generation zone 1 is equipped with a bioaerosol purification system. This system can be a sealing cover 5 added to the top of the micro-nano bubble in-situ generation zone 1, and an aerosol collection tube 8 inserted into the micro-nano bubble in-situ generation zone 1 on the sealing cover 5. The sealing cover 5 is a detachable, movable cover with a pre-drilled opening 6. This opening 6 should be kept sealed under normal circumstances; that is, a suitable-sized movable cover should cover the opening, and a transparent movable cover can be used for sealing.

[0049] like Figure 2 As shown, the lower end of the aerosol collection tube 8 is connected to the flared end 801. The flared end 801 is located above the liquid surface and as close as possible to the sealing cover plate 5. A micro-nano bubble generating device 4 is provided at the bottom of the micro-nano bubble in-situ generation zone 1. The bioaerosol is transported to the subsequent aerosol treatment unit through the aerosol collection tube 8 for unified treatment.

[0050] Furthermore, such as Figure 3 As shown, optionally, a subsequent aerosol treatment unit may not be provided. The subsequent aerosol treatment unit may also be replaced by the filter material 802 installed inside the aerosol collection tube 8. The filter material 802 is directly installed inside the aerosol collection tube 8 for air filtration. The air filtration may also be replaced by activated carbon adsorption, loading body packing, etc. The purified air is directly discharged into the air to achieve in-situ purification of bioaerosols.

[0051] Furthermore, the aerosol collection tube 8 can be replaced with an ultraviolet lamp tube 15 or other sterilization and disinfection water treatment components, installed below the sealing cover plate 5.

[0052] Further, the biological aerosol purification system formed by the combination of the sealing cover plate 5 and the aerosol collection pipe 8 can be replaced by the floating ball 16 at the gas-liquid interface.

[0053] The micro-nano bubble transition zone 2 is an open area, and the flow guide baffles 10 are arranged in the micro-nano bubble transition zone 2 in a staggered manner. The height of the flow guide baffles 10 is consistent with the height of the frame of the micro-nano bubble transition zone 2, and the width of the flow guide baffles 10 is slightly shorter than the width of the frame of the micro-nano bubble transition zone 2. After the micro-nano bubbles enter the micro-nano bubble transition zone 2 along with the water, the micro-nano bubbles experience a short transition along the flow guide baffles 10 from front to back to form a large number of nano bubbles.

[0054] The sludge-water coexistence reaction zone 3 is also an open area, and the sludge-water coexistence reaction zone 3 is provided with a stirring device 12 at the top, which can make the nano bubbles fully contact with the activated sludge and improve the efficiency of wastewater treatment. The sludge-water coexistence reaction zone 3 is provided with a water outlet pipe 13 on the outer side wall.

[0055] As shown in FIG. 1, optionally, the stirring device 12 can be replaced by an aeration device 14, such as a disc type microporous aerator, a pipe type microporous aerator, etc., which includes an air conveying pipe 1401 and a microporous aerator 1402. In the present application, a small amount of microporous aerators 1402 are installed, at this time, the traditional aeration mainly plays a role in fully mixing the nano bubbles with the activated sludge. Figure 4 Embodiment 2:

[0056] As shown in FIG. 2, the difference between this embodiment and embodiment 1 lies in the biological aerosol purification system. In this embodiment, the biological aerosol purification system includes a sealing cover plate 5 and an ultraviolet lamp 15, which can directly purify the biological aerosol in situ without a subsequent aerosol treatment unit. In the present application, the ultraviolet lamp can be replaced by other disinfection and sterilization water treatment components.

[0057] Figure 5 Embodiment 3:

[0058] As shown in FIG. 3, the difference between this embodiment and embodiments 1 and 2 lies in the biological aerosol purification system. In this embodiment, the biological aerosol purification system only includes a liquid surface loaded floating ball 16. In the present application, the floating ball 16 can inhibit the generation of foam at the gas-liquid interface, thereby reducing the formation and dispersion of biological aerosols.

[0059] Further, the present application provides a micro-nano bubble partitioned aeration tank and a biological aerosol purification method using the system, which comprises: Figure 6 Step 1, the wastewater enters the micro-nano bubble in-situ generation zone 1, and the micro-nano bubble generating device 4 generates micro-nano bubbles in the zone;

[0060] Step 2, the micro-nano bubbles generated in the micro-nano bubble in-situ generation zone 1 enter the micro-nano bubble transition zone 2 along with the water, and the micro-nano bubbles experience a short transition along the flow guide baffles 10 from front to back to form a large number of nano bubbles;

[0061] Step 3, the nano bubbles formed in the micro-nano bubble transition zone 2 enter the sludge-water coexistence reaction zone 3 along with the water, and the nano bubbles fully contact with the activated sludge under the action of the stirring device 12 or the aeration device 14, thereby improving the efficiency of wastewater treatment.​

[0062] The micro-nano bubble in-situ generating area mainly generates micro-nano bubbles by aeration of the raw sewage without activated sludge after the first treatment through a micro-nano bubble in-situ generating device.

[0063] Wherein, air is used as the aeration gas source; the water temperature is controlled to be 15-35℃, the gas-water ratio is controlled to be (0.3±0.05):1 in volume ratio, the air flow rate is controlled to be 60±10 mL / min, and the air pressure is set to be 0.3-0.5 MPa.

[0064] In the temperature range of 15-35℃, the micro-nano bubbles and the pollutants and microorganisms in the sewage fully interact with each other, and the sewage treatment efficiency is improved. If the water temperature is too low, the microbial activity is reduced, the mass transfer efficiency of the micro-nano bubbles is also reduced, and the decomposition and removal of the pollutants are affected; if the water temperature is too high, the bubble stability is poor and the microorganisms may be inactivated, which is also not conducive to the sewage treatment effect. When the air flow rate is controlled to be 60±10 mL / min and the air pressure is set to be 0.3 MPa, the system can reach the saturated dissolved oxygen level after aeration of the sewage for 5 min.

[0065] Fig. 7(a) is the dissolved oxygen charging situation under different air inlet pressures for 5 min, and Fig. 7(b) is the dissolved oxygen charging situation under different air flow rates.

[0066] The mechanism of the transformation of the micro-nano bubbles into nano bubbles, a large amount of micro-nano bubbles generated in the micro-nano bubble in-situ generating area enter the micro-nano bubble transition area. In the micro-nano bubble transition area, there are micro-bubbles (10-100 μm), sub-micro-bubbles (1-10 μm) and nano bubbles (<1 μm) in the water body. After stopping aeration, the micro-bubbles with larger particle size (>50 μm) will gradually fuse, float and break; according to the micro-bubble contraction mechanism, the gas-liquid interface existing around the micro-bubbles is subjected to the action of the liquid surface tension, the micro-nano bubbles with smaller particle size will gradually contract into nano bubbles with smaller size, a large amount of nano bubbles enter the sludge-water coexistence area after the transition, and the oxygen utilization rate and the sludge settling performance are improved through the full contact of the nano bubbles with the activated sludge by the stirring device, so as to improve the sewage treatment efficiency.

[0067] Step 2: A large amount of micro-nano bubbles enter the micro-nano bubble transition area 2 through the first water outlet 9, and are transformed into nano bubbles after the guide baffle 10. The micro-nano bubbles enter the micro-nano bubble transition area 2 along the guide baffle 10 from front to back and experience a short transition to form a large amount of nano bubbles.

[0068] In the micro-nano bubble transition area, the diameter of the micro-nano bubbles should be controlled to be <50 μm, and the concentration of the micro-nano bubbles should be controlled to be about 10 4 -10 7 individuals / mL.

[0069] The initial size of the micro-nano bubbles should meet the micro-nano bubbles with a diameter < 50 pm, because large bubbles have a tendency to rise rapidly to the surface and break, while micro-nano bubbles with a diameter < 50 pm tend to shrink and break under water. Moreover, the concentration of micro-nano bubbles should not be too high or too low. If the concentration of bubbles is too high, in the transition zone, bubbles may collide and merge with each other to form larger bubbles instead of being converted into nano bubbles; if the concentration is too low, the conversion efficiency will be greatly reduced. In practical applications, the concentration of micro-nano bubbles should be determined according to the specific device, the quality of the sewage and the processing requirements, and is generally controlled at about 10 4 -10 7 bubbles / mL.

[0070] To achieve micro-nano bubbles with a diameter < 50 pm, the concentration of micro-nano bubbles at 10 4 -10 7 bubbles / mL, and to realize the conversion of micro-nano bubbles into nano bubbles, the water flow speed should be controlled at 0.01-0.1 m / s.

[0071] In the micro-nano bubble transition zone, a higher water flow speed should be avoided, because a higher flow speed will generate a larger shear force and turbulence, which can cause a large number of micro-nano bubbles to be not completely converted into nano bubbles and to break rapidly. Generally, the water flow speed should be controlled in a relatively low range, at about 0.01-0.1 m / s, so that micro-nano bubbles with a certain diameter and concentration can have enough residence time in the transition zone to complete the conversion process, and the hydraulic residence time of the micro-nano bubble transition zone should be about 3-5 min.

[0072] A flow guide baffle 10 is arranged in the micro-nano bubble transition zone 2, which mainly plays a role in the transition and conversion of micro-nano bubbles into nano bubbles. The hydraulic residence time of this process needs to be determined according to the specific water quality characteristics and the properties of the generated micro-nano bubbles (concentration, particle size, etc.). When using a micro-nano bubble generator to aerate pure water, the water body becomes milky white due to the generation of a large number of micro-nano bubbles. After the aeration is completed, the milky white gradually fades, and the milky white phenomenon gradually disappears after 3-5 min, and the water body becomes clear. The disappearance of the milky white indicates that the larger bubbles have floated and broken or dissolved in the water, and at this time, there are mainly smaller micro-nano bubbles (especially nano bubbles) in the water. Therefore, the setting of the flow guide baffle 10 makes the hydraulic residence time of the micro-nano bubble transition zone be 3-5 min, which is beneficial to the transition and conversion of micro-nano bubbles into nano bubbles.

[0073] Step 3: Placing activated sludge in the sludge-water coexistence reaction zone 3, and the nano bubbles enter the sludge-water coexistence reaction zone 3 through the second water outlet 11, and under the action of the stirring device 12 in the sludge-water coexistence reaction zone 3, the nano bubbles fully contact with the activated sludge to realize the degradation of pollutants.

[0074] The purpose of placing stirring devices or aeration devices in the sludge-water coexistence reaction zone is to keep the activated sludge in a suspended state and in full contact with the nano-bubbles, thereby improving the oxygen dissolution efficiency and the pollutant removal efficiency. The stirring device can adopt a submersible stirrer, etc., and the aeration device can adopt a self-suction sewage aerator, etc. According to the provisions in “Energy Efficiency Limiting Value and Energy Efficiency Grade for Submersible Propeller Stirrers for Wastewater Treatment” (GB 37485-2019) and “Energy Efficiency Limiting Value and Energy Efficiency Grade for Rotating Aerators for Wastewater Treatment” (GB 37483-2019), the energy efficiency grade of the stirring device should meet 1.8 W / m 3 ~ 7.0 W / m 3 , and the energy efficiency grade of the aeration device should meet 0.7 kg / (kW·h)~3.4 kg / (kW·h).

[0075] In actual wastewater treatment processes, the ratio of activated sludge to nano-bubbles needs to be determined according to the properties of the wastewater (such as the content of organic matter, the types of pollutants, etc.), the removal rate requirements, and other factors. Generally speaking, in the traditional activated sludge process, the sludge concentration (measured by MLSS, mixed liquor suspended solids concentration) is usually around 2000~4000 mg / L, while the average particle size of the micro-nano bubbles generated by the micro-nano bubble generator (LF-1500) is 207.9 nm, and the bubble concentration is 1.8×10 7 . Figure 8 The size distribution range of the micro-nano bubbles of the present application.

[0076] The present application takes the LF-1500 type micro-nano bubble generator as an example to further illustrate the structure of the present application. The change of the dissolved oxygen level under 0.3 Mpa, 60±10 ml / min can be seen in Table 1, and the standard oxygen mass transfer coefficient (KLa) is calculated based on this data, that is, under standard conditions, the oxygen transport quantity to unit volume of liquid per unit time under the action of unit mass transfer driving force. During the aeration process, oxygen is continuously produced by the aeration device and dissolved in water, and the oxygen dissolution mass transfer situation can be reflected by KLa. The larger the KLa, the faster the exchange rate of dissolved oxygen in water, and the better the mass transfer effect. The relationship between the dissolved oxygen in water, KLa and time can be expressed as formula (1):

[0077]

[0078] Through mathematical operation, the above formula is integrated and further deduced to obtain formula (2):

[0079]

[0080] Wherein: KLa is the total oxygen mass transfer coefficient (1 / h); C Sis the saturated dissolved oxygen concentration (mg / L) of the liquid under the temperature condition; C0 is the initial dissolved oxygen concentration (mg / L); C is the dissolved oxygen concentration (mg / L) of the water at t time. t is the dissolved oxygen concentration (mg / L) of the water at t time.

[0081] Table 1 Dissolved oxygen level change of micro-nano bubble aeration under 0.3 Mpa, 60±10 ml / min

[0082]

[0083] It can be calculated that the KLa of micro-nano bubble aeration is 1.96. In the process of sewage treatment, generally speaking, the dissolved oxygen concentration under aerobic conditions should be kept at ≥2.0 mg / L, and generally maintained at 2-4 mg / L. Aerobic microorganisms can effectively decompose organic matter in sewage under a suitable dissolved oxygen environment. However, if the dissolved oxygen concentration is too high, for example, exceeds a certain limit (usually greater than 8-10 mg / L, with slight differences due to microbial species and other factors), it may have adverse effects on microorganisms. High concentration of dissolved oxygen will produce too many active oxygen free radicals in the microbial cells, which will destroy the biological macromolecules in the microbial cells, such as proteins, nucleic acids, etc., thereby inhibiting the normal metabolic activity of microorganisms.

[0084] Taking the condition of water temperature at 25℃ and standard atmospheric pressure as an example, the content of saturated dissolved oxygen (DO) is about 8.25 mg / L. When micro-nano bubble aeration is at 0.3 Mpa, 60±10 ml / min, the dissolved oxygen of micro-nano bubble aeration changes from 0 to 4 mg / L, t=0.338 h≈20 min, calculated by formula (2).

[0085] Therefore, when the air inlet pressure is 0.3 Mpa and the aeration amount is 60±10 ml / min, the aeration time can be set to 20-30 min, which can meet the dissolved oxygen demand of aerobic treatment. Due to the unique characteristics of micro-nano bubbles, the dissolved oxygen of micro-nano bubble water after aeration decays very slowly, so the dissolved oxygen level from the micro-nano bubble in-situ generation zone to the sludge-water coexistence reaction zone can reach a high level.

[0086] The present application divides the aeration tank into three regions: a micro-nano bubble in-situ generation zone, a micro-nano bubble transition zone and a sludge-water coexistence reaction zone, and only places activated sludge in the sludge-water coexistence reaction zone. Micro-nano bubbles are generated in the micro-nano bubble in-situ generation zone, and the generated micro-nano bubbles enter the sludge-water coexistence reaction zone after passing through the micro-nano bubble transition zone to fully contact with the activated sludge, thereby realizing the degradation of pollutants. The present application ingeniously utilizes the characteristics of different stages of micro-nano bubble aeration process, solves the problems of sludge floating, microbial cell damage and high emission level of biological aerosols, thereby improving the efficiency of sewage treatment and reducing the exposure risk.

[0087] Compared with a traditional aeration tank, the application ingeniously utilizes the characteristics of different stages of the micro-nano bubble aeration process, fully utilizes the characteristics of the micro-nano bubble oxygen mass transfer efficiency, long residence time and negative charge on the surface, and avoids the problems of sludge floating, microbial cell damage and high level of biological aerosol emission caused by a large number of micro-bubbles, and improves the sewage treatment efficiency.

[0088] The application is not limited to the above-mentioned embodiments, and on the basis of the technical solutions disclosed in the application, some substitutions and deformations can be made to some technical features by those skilled in the art according to the disclosed technical content without creative labor, and the substitutions and deformations are within the protection scope of the application.

Claims

1. A bioaerosol purification system with micro / nano bubble zoned aeration, characterized in that, include: The in-situ micro-nano bubble generation zone is equipped with a bioaerosol purification system and a micro-nano bubble generator, which is used to generate micro-nano bubbles from the incoming wastewater through the micro-nano bubble generator. The micro-nano bubble in-situ generation zone is equipped with a bio-aerosol purification system, which consists of a sealing cover plate added to the top of the micro-nano bubble in-situ generation zone, and an aerosol collection tube inserted into the micro-nano bubble in-situ generation zone on the sealing cover plate. The micro-nano bubble transition zone is equipped with flow guide baffles to facilitate the transition of micro-nano bubbles into a large number of nano bubbles; The mud-water coexistence reaction zone is equipped with a stirring device to ensure that the nanobubbles come into full contact with the activated sludge placed in the mud-water coexistence reaction zone, thereby achieving pollutant degradation.

2. The micro-nano bubble zoned aeration bioaerosol purification system according to claim 1, characterized in that, The lower end of the aerosol collection tube is connected to a flared nozzle, which is positioned above the liquid surface and as close as possible to the sealing cover.

3. The micro-nano bubble zoned aeration bioaerosol purification system according to claim 1, characterized in that, The aerosol collection tube was replaced with a UV lamp tube and installed below the sealing cover.

4. The micro-nano bubble zoned aeration bioaerosol purification system according to claim 1, characterized in that, Bioaerosols are transported to a subsequent aerosol treatment unit via an aerosol collection pipe. The subsequent aerosol treatment unit may be replaced by a filter material installed inside the aerosol collection pipe, which may be activated carbon adsorption or a loaded packing material.

5. The micro-nano bubble zoned aeration bioaerosol purification system according to claim 1, characterized in that, The micro-nano bubble in-situ generation zone is equipped with a bio-aerosol purification system, which consists of floats at the gas-liquid interface.

6. The micro-nano bubble zoned aeration bioaerosol purification system according to claim 1, characterized in that, The micro-nano bubble transition zone is an open area, and flow guide baffles are arranged alternately in the micro-nano bubble transition zone. The height of the flow guide baffles is the same as the height of the border of the micro-nano bubble transition zone, and the width of the flow guide baffles is slightly shorter than the width of the border of the micro-nano bubble transition zone.

7. The micro-nano bubble zoned aeration bioaerosol purification system according to claim 1, characterized in that, The mud-water coexistence reaction zone is an open zone, and it is equipped with a stirring device or an aeration device.

8. A method for purifying bioaerosols using micro-nano bubble zoned aeration in the purification system as described in any one of claims 1-7, characterized in that, include: Wastewater enters the micro-nano bubble in-situ generation zone. The influent water temperature is controlled, and micro-nano bubbles are generated in the micro-nano bubble in-situ generation zone by controlling the air-water ratio, air flow rate and air pressure through the micro-nano bubble generator. A large number of micro- and nano-bubbles enter the micro- and nano-bubble transition zone with water, controlling the water flow speed and hydraulic residence time, and are transformed into nano-bubbles by the guide baffle. Activated sludge is placed in the sludge-water coexistence reaction zone, and nanobubbles enter the sludge-water coexistence reaction zone. The ratio of the number of nanobubbles to the mass of activated sludge is controlled. Under the action of the stirring device or aeration device in the sludge-water coexistence reaction zone, the nanobubbles come into full contact with the activated sludge, thereby achieving pollutant degradation.

9. The bioaerosol purification method using micro / nano bubble zoned aeration according to claim 8, characterized in that, The inlet water temperature is 15℃~35℃, the air-to-water volume ratio is 0.3~0.5:1, the air flow rate is 50~70 mL / min, and the air pressure is 0.3~0.5 MPa; The water flow velocity is 0.01 - 0.1 m / s, and the hydraulic residence time is 3-5 min; Control the aeration rate to 50-70 ml / min and the aeration time to 20-30 min.

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