Micro-nano bubble partition aeration biological aerosol purification system and method

Abstract

The invention discloses a biological aerosol purification system and method for micro-nano bubble partition aeration, and the system comprises a micro-nano bubble in-situ generation zone, a micro-nano bubble transition zone and a mud-water coexistence reaction zone, and the micro-nano bubble in-situ generation zone is provided with a biological aerosol purification system. Micro-nano bubbles are generated through the micro-nano bubble generation device and entering sewage, and the micro-nano bubbles are transited to form a large number of nano bubbles through the micro-nano bubble transition area; sludge is placed in the sludge-water coexistence reaction area, and nanometer bubbles are in full contact with activated sludge, so that pollutant degradation is achieved. By utilizing the characteristics of different stages of the micro-nano bubble aeration process, the problems of sludge floating, microbial cell injury, high bioaerosol emission level and the like are solved, the sewage treatment efficiency is improved, and the exposure risk is reduced.

Description

Technical Field

[0001] The invention relates to the fields of sewage treatment and aerosol purification, and in particular to a novel bioaerosol purification system and method for micro-nano bubble zone aeration. Background Art

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

[0003] 1. Destroy the floc structure of activated sludge, causing the sludge to float and reduce the effluent quality.

[0004] 2. Damage the microbial cells in the activated sludge and reduce the efficiency of sewage treatment.

[0005] 3. A large amount of foam is generated at the air-water interface, resulting in the generation and escape of a large amount of bioaerosol, which seriously pollutes the surrounding air environment.

[0006] Therefore, there is an urgent need to provide a system and method that effectively avoids the large-scale emission of bioaerosols, ensures the smooth operation of the treatment process, and improves the efficiency of sewage treatment. Summary of the invention

[0007] In order to solve the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide a bioaerosol purification system and method with micro-nano bubble zoned aeration, which effectively avoids the sludge floating phenomenon caused by a large number of microbubbles existing in the in-situ generation stage of micro-nano bubbles by adopting zoned generation of micro-nano bubbles, nanobubble transition and mud-water coexistence reaction aeration, thereby improving the sludge settling performance.

[0008] The present invention is achieved through the following technical solutions.

[0009] One aspect of the present invention provides a bioaerosol purification system with micro-nano bubble zone aeration, comprising:

[0010] The micro-nano bubble in-situ generation area is equipped with a bioaerosol purification system and a micro-nano bubble generating device, which is used to generate micro-nano bubbles with the incoming sewage through the micro-nano bubble generating device;

[0011] The micro-nano bubble transition zone is equipped with a guide baffle for transitioning the micro-nano bubbles into a large number of nano bubbles;

[0012] The mud-water coexistence reaction zone is equipped with a stirring device for fully contacting the nanobubbles with the activated sludge placed in the mud-water coexistence reaction zone to achieve pollutant degradation.

[0013] Preferably, the micro-nano bubble in-situ generation area is provided with a bioaerosol purification system, which is a sealing cover plate added on the top of the micro-nano bubble in-situ generation area, and an aerosol collection tube inserted into the micro-nano bubble in-situ generation area is provided on the sealing cover plate. The sealing cover plate is a detachable movable cover plate, and a reserved hole is provided on it.

[0014] Preferably, the lower end of the aerosol collection tube is connected to a bell mouth, and the bell mouth is located above the liquid level and as close to the sealing cover as possible.

[0015] Preferably, the aerosol collection tube is replaced by an ultraviolet lamp tube and installed under the sealing cover.

[0016] Preferably, the bioaerosol is transported to a subsequent aerosol processing unit via an aerosol collection tube, and the subsequent aerosol processing unit may be replaced by a filter material installed inside the aerosol collection tube, wherein the filter material is activated carbon adsorbed or loaded with a carrier filler.

[0017] Preferably, the micro-nano bubble in-situ generation zone is provided with a bioaerosol purification system, which is a floating ball at the gas-liquid interface.

[0018] Preferably, the micro-nano bubble transition zone is an open zone, and guide baffles are arranged alternately in the micro-nano bubble transition zone. The height of the guide baffles is consistent with the height of the micro-nano bubble transition zone frame, and the width of the guide baffles is slightly shorter than the width of the micro-nano bubble transition zone frame.

[0019] Preferably, the mud-water coexistence reaction zone is an open zone, and the mud-water coexistence reaction zone is provided with a stirring device or an aeration device.

[0020] Another aspect of the present invention provides a bioaerosol purification method using micro-nano bubble zone aeration of the purification system, comprising:

[0021] The sewage enters the micro-nano bubble in-situ generation area, the water temperature is controlled, and the micro-nano bubble generating device is used to control the gas-water ratio, the air flow rate and the air pressure in the micro-nano bubble in-situ generation area to generate micro-nano bubbles;

[0022] A large number of micro-nano bubbles enter the micro-nano bubble transition zone with water, control the water flow velocity and hydraulic retention time, and are transformed into nano bubbles through the guide baffle;

[0023] Activated sludge is placed in the mud-water coexistence reaction zone, and nanobubbles enter the mud-water coexistence reaction zone. The mass ratio of the number of nanobubbles to the activated sludge is controlled, and the nanobubbles are fully contacted with the activated sludge under the action of a stirring device or an aeration device in the mud-water coexistence reaction zone to achieve pollutant degradation.

[0024] Preferably, the inlet water temperature is 15°C to 35°C, the gas-water volume ratio is 0.3 to 0.5:1, the inlet air flow rate is 50 to 70 mL / min, and the inlet air pressure is 0.3 to 0.5 MPa;

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

[0026] Control the aeration volume to 50-70 ml / min and the aeration time to 20-30 min.

[0027] The present invention adopts the above technical solution, which has the following beneficial effects:

[0028] 1. The micro-nano bubble zoned aeration tank is divided into a micro-nano bubble in-situ generation zone, a micro-nano bubble transition zone, and a mud-water coexistence reaction zone. The micro-nano bubble in-situ generation zone and the micro-nano bubble transition zone only contain sewage without activated sludge. Micro-nano bubbles are generated and transformed here, avoiding the destructive effects caused by direct contact between a large number of microbubbles and activated sludge. The mud-water coexistence reaction zone is an area where sewage, activated sludge and nanobubbles coexist. The presence of a large number of nanobubbles improves oxygen utilization and sludge sedimentation performance, thereby improving sewage treatment efficiency.

[0029] 2. A bioaerosol purification system is added on the top of the micro-nano bubble in-situ generation area to simultaneously inhibit the generation and emission of bioaerosols.

[0030] 3. Improved sludge settling performance. In the micro-nano bubble in-situ generation area, micro-nano bubbles are generated by controlling the inlet water temperature, gas-water ratio, inlet flow rate and inlet pressure, and converted into nano bubbles by controlling the water flow rate and hydraulic retention time. When the proportion of nano bubbles increases to more than 50%, the effect of micro-nano bubble aeration technology on sludge settling performance becomes positive, improving oxygen utilization and sludge settling performance, thereby improving sewage treatment efficiency. The use of zoned aeration effectively avoids the sludge floating phenomenon caused by a large number of microbubbles in the in-situ generation stage of micro-nano bubbles, and improves the sludge settling performance.

[0031] 4. High sludge activity. Nanobubbles cause almost no damage to bacteria in activated sludge flocs, can improve aerobic metabolism and growth of microorganisms, and increase oxygen utilization efficiency. The present invention only places activated sludge in the mud-water coexistence reaction zone, effectively avoiding microbial cell damage caused by a large number of microbubbles and improving sludge activity.

[0032] 5. Low exposure risk. The present invention adds a bioaerosol purification system in the micro-nano bubble in-situ generation area, which effectively avoids the large-scale emission of bioaerosols, thereby reducing the exposure risk.

[0033] 6. The process runs more smoothly. In the present invention, the micro-nano bubbles enter the mud-water coexistence reaction zone after passing through the micro-nano bubble in-situ generation zone and the micro-nano bubble transition zone, playing the role of pre-aeration. A stirring device is also provided to control the aeration conditions to ensure that the nano bubbles are in full contact with the activated sludge, which can ensure the smooth operation of the treatment process and improve the sewage treatment efficiency; in addition, the zoned aeration avoids the possibility of excessive aeration of the micro-nano bubbles, thereby avoiding the occurrence of sludge disintegration and ensuring the smooth operation of the activated sludge system. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0035] Figure 1 It is a schematic diagram of the structure of the present invention;

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

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

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

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

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

[0041] Figure 7 (a) and (b) show the dissolved oxygen oxygenation conditions under different inlet pressures;

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

[0043] The following are the descriptions of the reference numerals:

[0044] 1-micro-nano bubble in-situ generation zone, 2-micro-nano bubble transition zone, 3-mud-water coexistence reaction zone, 4-micro-nano bubble generating device, 5-sealing cover plate, 6-reserved orifice, 7-water inlet pipe, 8-aerosol collecting tube, 801-bell mouth, 802-filter material, 9-first water outlet, 11-second water outlet, 10-guiding 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 be described in detail below in conjunction with the accompanying drawings and specific embodiments. The exemplary embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0046] Embodiment 1:

[0047] like Figure 1 As shown, the present embodiment provides a bioaerosol purification system with micro-nano bubble partition aeration, which divides the aeration tank into three parts, namely, the micro-nano bubble in-situ generation zone 1, the micro-nano bubble transition zone 2 and the mud-water coexistence reaction zone 3, and the three areas are separated by a partition. A first water 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 water 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 water outlet 9 and the second water outlet 11 are respectively located on both sides of the partition of the micro-nano bubble transition zone 2, and are arranged alternately. The first water outlet 9 should be below the liquid level and as close to the bottom as possible, and the second water outlet 11 is distributed in the middle of the partition, and the first water outlet 9 and the second water outlet 11 are both distributed in multiple numbers along the upper and lower parts of the partition.

[0048] The micro-nano bubble in-situ generation area 1 is provided with a bioaerosol purification system, which can be a sealing cover plate 5 added on the top of the micro-nano bubble in-situ generation area 1, and an aerosol collection tube 8 inserted into the micro-nano bubble in-situ generation area 1 is provided on the sealing cover plate 5. The sealing cover plate 5 is a detachable movable cover plate, on which a reserved orifice 6 is provided, and the reserved orifice 6 should be kept in a closed state without special circumstances, that is, a movable cover plate of suitable size should be covered above the reserved orifice, and a movable cover plate of transparent material can be used for sealing.

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

[0050] Further, if Figure 3 As shown, optionally, the subsequent aerosol processing unit may not be provided, and the subsequent aerosol processing 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, addition of carrier fillers, 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 by an ultraviolet lamp 15 or other sterilizing and disinfecting water treatment components, which are installed below the sealing cover plate 5 .

[0052] Furthermore, the bioaerosol purification system composed of the sealing cover plate 5 and the aerosol collection tube 8 can be replaced by a floating ball 16 at the gas-liquid interface.

[0053] Among them, the micro-nano bubble transition zone 2 is an open area, and the micro-nano bubble transition zone 2 is staggered with guide baffles 10. The height of the guide baffles 10 is consistent with the height of the frame of the micro-nano bubble transition zone 2, and the width of the 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 with the water, they undergo a short transition from front to back along the guide baffles 10 to form a large number of nano bubbles.

[0054] The mud-water coexistence reaction zone 3 is also an open zone. A stirring device 12 is provided on the top of the mud-water coexistence reaction zone 3 to allow the nanobubbles to fully contact with the activated sludge and improve the sewage treatment efficiency. A water outlet pipe 13 is provided on the outer wall of the mud-water coexistence reaction zone 3.

[0055] like Figure 4 As shown, optionally, the stirring device 12 can be replaced by an aeration device 14, such as a disc-type microporous aerator, a tubular microporous aerator, etc., including an air delivery pipe 1401 and a microporous aerator 1402. In the present invention, a small amount of microporous aerator 1402 can be installed. At this time, the traditional aeration mainly plays the role of fully mixing the nanobubbles with the activated sludge.

[0056] Embodiment 2:

[0057] like Figure 5 As shown, the difference between this embodiment and embodiment 1 is that the bioaerosol purification system is different. In this embodiment, the bioaerosol purification system includes a sealing cover plate 5 and an ultraviolet lamp 15. The ultraviolet lamp 15 can directly purify the bioaerosol in situ without the need for a subsequent aerosol processing unit. In the present invention, the ultraviolet lamp can be replaced by other water treatment components for disinfection and sterilization.

[0058] Embodiment 3:

[0059] like Figure 6 As shown, the difference between this embodiment and Embodiment 1 and Embodiment 2 lies in the different bioaerosol purification systems. In this embodiment, the bioaerosol purification system only includes a float 16 loaded on the liquid surface. In the present invention, the float 16 can suppress the generation of foam at the gas-liquid interface, thereby reducing the formation and escape of bioaerosols.

[0060] Furthermore, the embodiment of the present invention provides a micro-nano bubble partition aeration tank and a bioaerosol purification method using the system, including:

[0061] Step 1, sewage enters the micro-nano bubble in-situ generation area 1, and micro-nano bubbles are generated in the area by the micro-nano bubble generating device 4;

[0062] In the micro-nano bubble in-situ generation area, the raw sewage that has undergone primary treatment without placing activated sludge is aerated mainly through the micro-nano bubble in-situ generation device to generate micro-nano bubbles.

[0063] Air is used as the aeration gas source; the inlet water temperature is controlled at 15°C to 35°C, and the air-water ratio is (0.3±0.05):1 by volume. The inlet flow rate is controlled at 60±10mL / min, and the inlet pressure is set to 0.3-0.5MPa.

[0064] Considering that within the temperature range of 15℃~35℃, the micro-nano bubbles fully interact with the pollutants and microorganisms in the sewage to improve the sewage treatment efficiency. If the water temperature is too low, the microbial activity will decrease. Although the micro-nano bubbles have good stability, the mass transfer efficiency will also decrease, affecting the decomposition and removal of pollutants; 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 at 60±10mL / min and the air pressure is set to 0.3MPa, the sewage aeration system can reach the saturated dissolved oxygen level after 5min of aeration.

[0065] Figure 7(a) shows the dissolved oxygen oxygenation at different intake pressures within 5 min, and Figure 7(b) shows the dissolved oxygen oxygenation at different intake flow rates.

[0066] The mechanism of micro-nano bubbles transforming into nano-bubbles: a large number of micro-nano bubbles generated in the micro-nano bubble in-situ generation zone enter the micro-nano bubble transition zone. In the micro-nano bubble transition zone, micro-bubbles (10-100μm), sub-micron bubbles (1-10μm) and nano-bubbles (<1μm) exist in the water. After aeration stops, micro-bubbles with larger particles (>50μm) will gradually merge, float and rupture; and according to the micro-bubble contraction mechanism, the gas-liquid interface around the bubbles makes them affected by the surface tension of the liquid, and the micro-nano bubbles with smaller particle sizes will gradually shrink into smaller nano-bubbles. After the transition zone conversion, a large number of nano-bubbles enter the mud-water coexistence zone, and are fully in contact with the activated sludge through the stirring device, which improves the oxygen utilization rate and sludge settling performance, thereby improving the sewage treatment efficiency.

[0067] Step 2, a large number of micro-nano bubbles enter the micro-nano bubble transition zone 2 through the first water outlet 9, and are transformed into nano bubbles after passing through the guide baffle 10. After the micro-nano bubbles enter the micro-nano bubble transition zone 2 with water, they undergo a short transition from front to back along the guide baffle 10 to form a large number of nano bubbles.

[0068] In order to better achieve the transformation from micro-nano bubbles to nanobubbles in the transition zone, the diameter of micro-nano bubbles should be controlled to be less than 50 μm, and the concentration of micro-nano bubbles should be 10 4 -10 7 About pcs / mL.

[0069] The initial size of the micro-nano bubbles should meet the requirement of micro-nano bubbles with a diameter of <50μm, because large bubbles tend to rise and burst quickly on the water surface, while micro-nano bubbles with a diameter of <50μm tend to shrink and burst underwater. In addition, the concentration of micro-nano bubbles cannot be too high or too low. If the bubble concentration is too high, the bubbles may collide and merge with each other in the transition zone to form larger bubbles instead of converting into nanobubbles; 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, sewage quality and treatment requirements, and is generally controlled at 10 4 -10 7 The appropriate amount is about pcs / mL.

[0070] To achieve a diameter of micro-nano bubbles <50 μm, the concentration of micro-nano bubbles should be 10 4 -10 7 / mL, to achieve the transformation of micro-nano bubbles into nano bubbles, which can be achieved by controlling the water flow rate, which should be controlled at 0.01-0.1m / s.

[0071] In the transition zone of micro-nano bubbles, high water flow velocity should be avoided, because too high flow velocity will produce greater shear force and turbulence, which may cause a large number of micro-nano bubbles to be not completely converted into nano bubbles and burst quickly. Generally speaking, the water flow velocity should be controlled in a relatively low range, preferably around 0.01-0.1m / s, so that micro-nano bubbles of a certain diameter and concentration can have enough residence time in the transition zone to complete the conversion process. The hydraulic residence time in the transition zone of micro-nano bubbles should be 3-5min.

[0072] The guide baffle 10 is set in the micro-nano bubble transition zone 2, which mainly plays the role of transitional transformation of micro-nano bubbles to nano bubbles. The hydraulic retention 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 the micro-nano bubble generator is used 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. After 3-5 minutes, the milky white phenomenon of the water body gradually disappears, and the water body becomes clear. The disappearance of the milky white indicates that the larger bubbles have floated up, broken or dissolved in the water, and at this time, the water mainly exists in smaller micro-nano bubbles (especially nano bubbles). Therefore, the guide baffle 10 is set so that the hydraulic retention time of the micro-nano bubble transition zone is 3-5 minutes, which is conducive to the transitional transformation of micro-nano bubbles to nano bubbles.

[0073] Step 3, placing activated sludge in the mud-water coexistence reaction zone 3, the nanobubbles enter the mud-water coexistence reaction zone 3 through the second water outlet 11, and are fully contacted with the activated sludge under the action of the stirring device 12 in the mud-water coexistence reaction zone 3 to achieve pollutant degradation.

[0074] The purpose of placing a stirring device or an aeration device in the mud-water coexistence reaction zone is to keep the activated sludge in suspension and in full contact with the nanobubbles, thereby improving the dissolved oxygen efficiency and pollutant removal efficiency. The stirring device can be a submersible mixer, and the aeration device can be a self-priming sewage aerator. According to the "Energy Efficiency Limits and Energy Efficiency Grades of Submersible Plug-Flow Mixers for Sewage Treatment" (GB 37485-2019) and "Energy Efficiency Limits and Energy Efficiency Grades of Rotary Aerators for Sewage Treatment" (GB 37483-2019), the energy efficiency grade of the stirring device shall comply with 1.8W / m 3 ~7.0W / m 3 The energy efficiency level of the aeration device should be in the range of 0.7kg / (kW·h) to 3.4kg / (kW·h).

[0075] In the actual sewage treatment process, the ratio of activated sludge to nanobubbles depends on the nature of the sewage (such as organic matter content, type of pollutants, etc.), 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 207.9nm, and the bubble concentration is 1.8×10 7 Pieces / mL. Figure 8 is the size distribution range of the micro-nano bubbles of the present invention.

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

[0077]

[0078] Through mathematical operations, integrating the above formula and further deducing it, we can get formula (2):

[0079]

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

[0081] Table 1 Changes in dissolved oxygen levels under micro-nano bubble aeration at 0.3 MPa and 60 ± 10 ml / min

[0082]

[0083] After calculation, it can be known 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 maintained at ≥2.0mg / L, generally maintained at 2-4mg / 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, exceeding a certain limit (usually greater than 8-10mg / L, slightly different due to factors such as microbial species), it may have an adverse effect on microorganisms. High concentrations of dissolved oxygen will cause excessive active oxygen free radicals to be produced in microbial cells. These free radicals will destroy biological macromolecules in microbial cells, such as proteins, nucleic acids, etc., thereby inhibiting the normal metabolic activities of microorganisms.

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

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

[0086] The present invention divides the aeration tank into three areas: a micro-nano bubble in-situ generation area, a micro-nano bubble transition area, and a mud-water coexistence reaction area, and only places activated sludge in the mud-water coexistence reaction area, generates micro-nano bubbles in the micro-nano bubble in-situ generation area, and the generated micro-nano bubbles enter the mud-water coexistence reaction area after passing through the micro-nano bubble transition area to fully contact with the activated sludge, thereby achieving pollutant degradation. The present invention cleverly utilizes the characteristics of different stages of the micro-nano bubble aeration process, solves the problems of sludge floating, microbial cell damage, and high bioaerosol emission levels, thereby improving sewage treatment efficiency and reducing exposure risks.

[0087] Compared with the traditional aeration tank, the change of the structural form of the present invention cleverly utilizes the characteristics of different stages of the micro-nano bubble aeration process, which not only gives full play to the high oxygen mass transfer efficiency, long residence time and negative charge on the surface of the micro-nano bubble, but also avoids the problems of sludge floating, microbial cell damage and high level of bioaerosol emission caused by a large number of microbubbles, thereby improving the sewage treatment efficiency.

[0088] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A bioaerosol purification system with micro-nano bubble zone aeration, characterized in that: include: The micro-nano bubble in-situ generation area is equipped with a bioaerosol purification system and a micro-nano bubble generating device, which is used to generate micro-nano bubbles with the incoming sewage through the micro-nano bubble generating device; The micro-nano bubble transition zone is equipped with a guide baffle for transitioning the micro-nano bubbles into a large number of nano bubbles; The mud-water coexistence reaction zone is equipped with a stirring device for fully contacting the nanobubbles with the activated sludge placed in the mud-water coexistence reaction zone to achieve pollutant degradation.

2. The bioaerosol purification system with micro-nano bubble zone aeration according to claim 1 is characterized in that: The micro-nano bubble in-situ generation area is provided with a bioaerosol purification system, which is a sealing cover plate added on the top of the micro-nano bubble in-situ generation area, and an aerosol collection tube inserted into the micro-nano bubble in-situ generation area is provided on the sealing cover plate.

3. The bioaerosol purification system with micro-nano bubble zone aeration according to claim 2 is characterized in that: The lower end of the aerosol collection tube is connected to the bell mouth, and the bell mouth is located above the liquid level and as close to the sealing cover as possible.

4. The bioaerosol purification system with micro-nano bubble zone aeration according to claim 2 is characterized in that: The aerosol collection tube is replaced by a UV lamp tube and installed under the sealing cover.

5. The bioaerosol purification system with micro-nano bubble zone aeration according to claim 1 is characterized in that: The bioaerosol is transported to the subsequent aerosol processing unit through the aerosol collection tube, and the subsequent aerosol processing unit may be replaced by a filter material installed inside the aerosol collection tube, and the filter material is activated carbon adsorption or loaded with carrier filler.

6. The bioaerosol purification system with micro-nano bubble zone aeration according to claim 1 is characterized in that: The micro-nano bubble in-situ generation area is provided with a bioaerosol purification system, which is a floating ball at the gas-liquid interface.

7. The bioaerosol purification system with micro-nano bubble zone aeration according to claim 1 is characterized in that: The micro-nano bubble transition zone is an open zone, and flow guide baffles are arranged alternately in the middle of the micro-nano bubble transition zone. The height of the flow guide baffles is consistent with the height of the micro-nano bubble transition zone frame, and the width of the flow guide baffles is slightly shorter than the width of the micro-nano bubble transition zone frame.

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

9. A bioaerosol purification method using micro-nano bubble zoned aeration according to any one of claims 1 to 8, characterized in that: include: The sewage enters the micro-nano bubble in-situ generation area, the water temperature is controlled, and the micro-nano bubble generating device is used to control the gas-water ratio, the air flow rate and the air pressure in the micro-nano bubble in-situ generation area to generate micro-nano bubbles; A large number of micro-nano bubbles enter the micro-nano bubble transition zone with water, control the water flow velocity and hydraulic retention time, and are transformed into nano bubbles through the guide baffle; Activated sludge is placed in the mud-water coexistence reaction zone, and nanobubbles enter the mud-water coexistence reaction zone. The mass ratio of the number of nanobubbles to the activated sludge is controlled, and the nanobubbles are fully contacted with the activated sludge under the action of a stirring device or an aeration device in the mud-water coexistence reaction zone to achieve pollutant degradation.

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

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