An operation method for a high oxygen utilization aerobic MBBR system

Abstract

This invention discloses an operation method for a high-oxygen-utilization-rate aerobic MBBR system, belonging to the field of water treatment technology. The operating system includes a reaction tank, within which, along the water flow direction, are sequentially arranged a first corridor, a first reaction tank, a second corridor, a second reaction tank, a third corridor, a third reaction tank, and a defoaming tank. Nano-aerators are installed on the bottom surface of the first, second, and third corridors, each connected to a nano-gas generator. Suspended carriers and agitators are installed in the first, second, and third reaction tanks. A perforated pipe aerator is installed at the bottom of the defoaming tank. Wastewater to be treated enters through the first corridor. The aeration rate of the first corridor is greater than that of the second corridor, and the aeration rate of the second corridor is greater than that of the third corridor. This invention achieves higher nano-bubble oxygen utilization, further reduces energy consumption, and exhibits high removal rates and stable treatment of oxygen-consuming pollutants.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and specifically to an operation method for a high oxygen utilization rate aerobic MBBR system. Background Technology

[0002] Moving bed biofilm reactors (MBBRs) utilize a biofilm process, offering the advantage of strong enrichment of functional bacteria. While this improves overall biochemical treatment efficiency, the macroscopic effect is also related to mass and oxygen transfer. Limited by oxygen and mass transfer, the treatment load of biofilms fluctuates significantly. To fully release the activity of microorganisms, large amounts of oxygen are often required in practical engineering applications. Traditional aeration methods primarily use microporous or perforated aeration, which result in large bubbles with a small gas-liquid contact area and rapid gas rise velocity with short gas-liquid contact time, leading to significant aeration waste. Nanobubbles, with their large surface area and slow rise velocity, are suitable for MBBR oxygenation facilities. They not only improve oxygen utilization and reduce energy consumption but also achieve higher treatment efficiency due to enhanced oxygen transfer.

[0003] Current research reports in existing technologies include:

[0004] CN 106186558A discloses a high-efficiency oxygen-supplying suspended carrier fluidized bed wastewater treatment system using nanobubbles, comprising a screen, an anaerobic tank, an anoxic tank, an MBBR nanobubble bioreactor, and a secondary sedimentation tank. The MBBR nanobubble bioreactor contains suspended carriers with a high specific surface area suitable for microbial attachment and reproduction. The MBBR nanobubble bioreactor is connected to a nanobubble generator with oxygen as its air source, responsible for supplying nanobubbles into the MBBR nanobubble bioreactor to form a high-density nanobubble water body. This system combines nanobubble technology with suspended carrier fluidized bed technology to form a novel wastewater treatment system and process, overcoming the drawbacks of existing activated sludge systems such as high energy consumption and forced aeration. However, the main technical problem with this treatment device and process is that the system is merely a combination of nanobubbles and suspended carrier fluidized bed technology: ① Its beneficial effects are only reflected in nanobubbles and aeration, failing to demonstrate the beneficial effects of combining nanobubbles and suspended carrier fluidized bed technology. The beneficial effects such as high system volumetric loading described in the document are all brought about by the biofilm process itself and are unrelated to nanobubble aeration. ② The operation process failed to adequately consider the mass and oxygen transfer issues of the biofilm under nano-aeration, which could easily lead to biofilm blockage and reduce system performance. ③ The reactor structure design failed to effectively utilize the advantage of the long residence time of nanobubbles, thus failing to further leverage the process advantages.

[0005] It is evident that there are still many problems in the application of micro-nano aeration in the field of water treatment, especially regarding process operation, and the existing technology needs further improvement. Summary of the Invention

[0006] The purpose of this invention is to provide an operation method for a high oxygen utilization aerobic MBBR system. Compared with conventional methods, this method has a higher removal rate of organic matter and ammonia nitrogen and a more stable treatment effect.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for operating a high oxygen utilization aerobic MBBR system includes the following steps:

[0009] a. Preparing to run the system

[0010] The operating system includes a reaction tank, within which a first corridor, a first reaction tank, a second corridor, a second reaction tank, a third corridor, a third reaction tank, and a defoaming tank are sequentially arranged along the water flow direction. Nano-aerators are installed on the bottom surfaces of the first, second, and third corridors, and each nano-aerator is connected to a nano-gas generator. Suspended carriers and agitators are installed in the first, second, and third reaction tanks, and a perforated pipe aerator is installed at the bottom of the defoaming tank.

[0011] The volume ratio of the first, second, and third reaction tanks is 5:3:2. The first, second, and third corridors each occupy 10% to 15% of the volume of their respective first, second, and third reaction tanks.

[0012] The specific gravity of the suspended carrier in each of the three reaction tanks was 1.10~1.20 g / cm³. 3 The thickness of each is 3mm~5mm; the pore size of the suspended carrier in the first reaction tank is 5~6mm, the pore size of the suspended carrier in the second reaction tank is 4~5mm, and the pore size of the suspended carrier in the third reaction tank is 3~4mm.

[0013] b. The wastewater to be treated enters from the first channel, and the SS in the influent is less than 50 mg / L; the aeration rate of the first channel is greater than that of the second channel, and the aeration rate of the second channel is greater than that of the third channel.

[0014] The operation method includes the following steps:

[0015] (1) Normal operation phase: The first, second, and third corridors are supplied with gas normally, and the stirring power density of the first reaction tank is controlled at 10~12W / m. 3 The stirring power density of the second and third reaction tanks is 7~10 W / m³.3 ;

[0016] (2) High-intensity hydraulic shear stage: The first, second, and third corridors are supplied with gas normally, and the stirring power density of the first reaction tank is controlled at 17~20W / m. 3 The stirring power density of the second reaction tank is 12~15W / m³. 3 The stirring power density of the third reaction tank is 7~10 W / m³. 3 ;

[0017] (3) For the reaction tank with the removal of organic matter as the core, the strong hydraulic shear stage is started once every 10 to 15 days, and each time it is started for 2 to 3 hours; for the reaction tank with the removal of ammonia nitrogen as the core, the strong hydraulic shear stage is started once every 20 to 25 days, and each time it is started for 1 to 2 hours.

[0018] The above-mentioned high oxygen utilization rate aerobic MBBR system operation method is as follows: the air supply of the first corridor is 60%~70% of the theoretical value of the overall aeration volume, the air supply of the second corridor is 10%~15% of the theoretical value of the overall aeration volume, and the air supply of the third corridor is 0%~5% of the theoretical value of the overall aeration volume.

[0019] The above-mentioned operation method of a high oxygen utilization aerobic MBBR system uses nano-aerators with a pore size of 100nm~500nm.

[0020] In the above-mentioned operation method of a high oxygen utilization aerobic MBBR system, intercepting screens are installed at the outlets between the first corridor and the first reaction tank, the first reaction tank and the second corridor, the second corridor and the second reaction tank, the second reaction tank and the third corridor, the third corridor and the third reaction tank, and the third reaction tank and the defoaming tank.

[0021] In the above-mentioned operation method of a high-oxygen-utilization aerobic MBBR system, the specific gravity of the suspended carrier is 1.15 g / cm³. 3 The thickness of each is 4mm.

[0022] The above-mentioned method for operating a high oxygen utilization aerobic MBBR system uses a variable frequency agitator as the stirrer.

[0023] Compared with the prior art, the present invention brings the following beneficial technical effects:

[0024] (1) This invention proposes an operation method for a high oxygen utilization rate aerobic MBBR system. The reaction tanks are arranged in the order of water flow direction as a first corridor, a first reaction tank, a second corridor, a second reaction tank, a third corridor, a third reaction tank and a defoaming tank. The aeration rate of the first corridor is greater than that of the second corridor, and the aeration rate of the second corridor is greater than that of the third corridor. The purpose of this design is to improve the treatment efficiency of the first reaction tank. Unused nanobubbles enter the subsequent reaction tanks. Through experimental research, when the air supply of the first corridor is 60% to 70% of the theoretical value of the overall aeration rate, mass transfer can be enhanced and the treatment efficiency can be improved.

[0025] (2) The present invention has high oxygen utilization rate and energy saving and consumption reduction. Nano aerators are used in the first, second and third corridors. The bubble diameter is small and the effective surface area is large. At the same time, the graded treatment and gradient reduction aeration method increases the gas-liquid contact time and further improves the oxygen utilization rate. Compared with single-stage micro-nano aeration, it saves 30% of the gas volume and more than 60% of the gas volume compared with conventional aeration methods.

[0026] (3) The present invention has high and stable treatment efficiency. Microbial enrichment adopts the form of biological fluidized bed, which has a higher enrichment capacity of core functional bacteria. Furthermore, the mass and oxygen transfer process is enhanced through micro-nano aeration. The biofilm thickness is maintained through fluidization control, ensuring a highly efficient mass and oxygen transfer process. The system has high and stable treatment efficiency, reduces the land area by 70% compared to the traditional activated sludge process, and further reduces it by 20% compared to the traditional MBBR.

[0027] (4) The present invention features a graded treatment process that is highly efficient and controllable. Based on the advantages of the MBBR process and the long residence time of nanobubbles, a graded treatment and gradient reduction aeration method are adopted to prolong the gas-liquid contact time and reduce the aeration volume. At the same time, the graded treatment, based on different fluidized shear forces, reduces the complexity of the installation and control of the agitator.

[0028] (5) The reactor arrangement achieves complete separation of the nano aerator and the suspended carrier, protecting the nano aerator from the influence of the suspended carrier and improving its service life. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings:

[0030] Figure 1 This is a schematic diagram of the operating system structure of the present invention;

[0031] Figure 2 This is a graph showing the changes in ammonia nitrogen concentration in the effluent of each functional zone under different aeration methods.

[0032] In the diagram: 1-Nano aerator; 2-Nano gas generator; 3-Agitator; 4-Outlet interception screen; 5-Perforated pipe aerator; 6-First reaction tank; 7-Second reaction tank; 8-Third reaction tank; 9-Defoaming tank; 10-First corridor; 11-Second corridor; 12-Third corridor; 13-Inlet; 14-Outlet. Detailed Implementation

[0033] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0034] It is understood that the connection relationships described in this application refer to direct or indirect connections. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components. For example, A can be directly connected to C, and C can be directly connected to B, thus achieving a connection between A and B through C. It is also understood that the "A connects to B" described in this application can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0035] In the description of this application, the words "first," "second," etc., are used only to distinguish different objects and do not limit the quantity or order of execution, nor do they imply that they must be different. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0036] The main technical concept of this invention lies in fully utilizing the characteristics of biofilm technology and the advantages of nanobubbles to achieve a simultaneous energy-saving and highly efficient pollution removal process. The treatment effect of biofilm technology is closely related to mass and oxygen transfer; improved mass and oxygen transfer capacity means improved treatment effect, thereby reducing land occupation for wastewater treatment. Nanobubbles solve the oxygen transfer problem, but they fail to solve the mass transfer problem, i.e., the fluidization problem, which affects the high-efficiency treatment performance of MBBR. Simultaneously, the long residence time of nanobubbles, extending the gas-liquid contact time, will further improve oxygen utilization and reduce oxygenation energy consumption. Therefore, the starting point of this invention is how to achieve good mass transfer and fluidization, and how to extend the gas-liquid contact time to achieve efficient pollutant treatment and energy saving.

[0037] like Figure 1As shown, the operating system of this invention includes a reaction tank, which is divided into a first corridor 10, a first reaction tank 6, a second corridor 11, a second reaction tank 7, a third corridor 12, a third reaction tank 8, and a defoaming tank 9 according to the water inlet direction. The first corridor 10 is equipped with an inlet 13, and the defoaming tank 9 is equipped with an outlet 14. Nano-aerators 1 are installed on the bottom surface of the first corridor 10, the second corridor 11, and the third corridor 12, providing nano-bubbles into the corridors, which then enter the adjacent reaction tanks. Each nano-aerator is connected to a nano-gas generator 2. Suspended carriers and stirrers 3 are installed in the first, second, and third reaction tanks, and a perforated pipe aerator 5 is installed at the bottom of the defoaming tank 9.

[0038] The volume ratio of the first, second, and third reaction tanks is 5:3:2. The first, second, and third corridors each occupy 10% to 15% of the volume of their respective first, second, and third reaction tanks. This arrangement can improve water treatment efficiency, increase the actual gas-liquid contact time of the primary aeration stage, improve oxygen utilization, and reduce the aeration volume and energy consumption of the second and third stages.

[0039] The specific gravity of the suspended carrier in each of the three reaction tanks was 1.10~1.20 g / cm³. 3 The thickness of the suspended carriers is 3mm~5mm; the pore size of the suspended carriers in the first reaction tank is 5~6mm, the pore size of the suspended carriers in the second reaction tank is 4~5mm, and the pore size of the suspended carriers in the third reaction tank is 3~4mm; the characteristics of the suspended carriers are matched with those of nanobubbles. The influent substrate gradually decreases from the first reaction tank to the third reaction tank, mass transfer weakens, and the biofilm thickness becomes thinner. Therefore, the pore size decreases from the first reaction tank to the third reaction tank to increase the effective surface area, thereby ensuring the overall pollution treatment volume load.

[0040] The pore size of the nano aerator is 100nm~500nm; water interception screens 4 are installed at the outlets between the first corridor and the first reaction tank, the first reaction tank and the second corridor, the second corridor and the second reaction tank, the second reaction tank and the third corridor, the third corridor and the third reaction tank, and the third reaction tank and the defoaming tank.

[0041] The specific operation method of the above system is as follows:

[0042] The wastewater to be treated enters from the first channel, and the SS in the influent is less than 50 mg / L; the aeration rate of the first channel is greater than that of the second channel, and the aeration rate of the second channel is greater than that of the third channel.

[0043] The operation method includes the following steps:

[0044] (1) Normal operation phase: The first, second, and third corridors are supplied with gas normally, and the stirring power density of the first reaction tank is controlled at 10~12W / m. 3 The stirring power density of the second and third reaction tanks is 7~10 W / m³. 3 ;

[0045] (2) High-intensity hydraulic shear stage: The first, second, and third corridors are supplied with gas normally, and the stirring power density of the first reaction tank is controlled at 17~20W / m. 3 The stirring power density of the second reaction tank is 12~15W / m³. 3 The stirring power density of the third reaction tank is 7~10 W / m³. 3 ;

[0046] (3) For the reaction tank with the removal of organic matter as the core, the strong hydraulic shear stage is started once every 10 to 15 days, and each time it is started for 2 to 3 hours; for the reaction tank with the removal of ammonia nitrogen as the core, the strong hydraulic shear stage is started once every 20 to 25 days, and each time it is started for 1 to 2 hours.

[0047] The present invention will be further described below with reference to specific embodiments:

[0048] Example 1:

[0049] To verify the impact of suspended solids (SS) in the influent of the operating system on nano-aeration, a comparative experiment was conducted. The effective tank volume of the operating system was 5 m³. 3 The influent was from the aerobic tank of a municipal wastewater treatment plant in northern China. Suspended solids (SS) were controlled at 30 mg / L, 50 mg / L, 80 mg / L, and 100 mg / L. The system underwent aerobic reactions with the same airflow rate. A pressure gauge was connected to one end of each nano-aerator. The system operated continuously for a total of 6 months.

[0050] During operation, when the suspended solids (SS) were controlled at 30 mg / L and 50 mg / L, the pressure gauge readings remained relatively stable between 2.10 and 2.15 MPa over the long term. However, when the SS increased to 80 mg / L, the pressure gauge readings showed a continuous upward trend starting from day 159, reaching a final pressure of 2.18 MPa after six months of operation. When the SS increased to 100 mg / L, the pressure increase occurred as early as day 135, with a final pressure of 2.22 MPa. The pressure increase was mainly due to SS particles clogging the pores of the nano-aerators, thus increasing aeration resistance. Compared to engineering operations, this experiment was relatively short, but the results show that when SS exceeded 80 mg / L, its impact on the nano-aerators became apparent during system operation. Therefore, in actual operation, the SS in the system influent should be kept below 50 mg / L.

[0051] Example 2:

[0052] Through experiments, the effects of three key parameters—specific gravity, pore size, and thickness of the suspended carrier—on the performance of nano-aeration were determined.

[0053] (1) First, the specific gravity of the suspended carrier was selected in the experiment as 0.96 g / cm³. 3 1.05g / cm 3 1.15 g / cm 3 1.25 g / cm 3 Four specifications were tested, all using cylindrical suspended carriers with a diameter of 25 mm, a thickness of 10 mm, and an average pore size of 4.5 mm. The test water was the influent from the aerobic tank of a municipal wastewater treatment plant in northern China, with SS controlled below 50 mg / L and ammonia nitrogen at 40 mg / L. The effective tank volume of the MBBR reactor was 500 L, with a filling rate of 50%, and continuous flow operation was maintained. The same aeration rate and stirring power were controlled to ensure oxygen supply and fluidization of the suspended carrier. The test results are shown in Table 1. Table 1 shows that the specific gravity of the suspended carrier mainly affects the fluidization of the operating system, which in turn indirectly affects biofilm formation and treatment efficiency. Better fluidization results in more uniform distribution of the suspended carrier, better biofilm formation, and higher treatment performance. For the nano-aeration system, nanobubbles adhere to the suspended carrier during their ascent, thereby increasing the buoyancy of the suspended carrier and effectively reducing its specific gravity. Therefore, the specific gravity of the suspended carrier itself is relatively high, at 1.15 g / cm³. 3 The suspended carrier is suitable for nano-aeration systems.

[0054] Table 1. Effect of suspended carrier specific gravity on system processing performance

[0055]

[0056] (2) Secondly, regarding the study of the thickness of the suspended carrier, three thicknesses of suspended carriers of 10 mm, 4 mm, and 2 mm were selected for the experiment, with a specific gravity of 1.15 g / cm³. 3 The diameter was 25 mm, and the average pore size was 4.5 mm. The test water was the influent of the aerobic tank of a municipal wastewater treatment plant in northern China. SS was controlled below 50 mg / L, ammonia nitrogen was controlled at 40 mg / L, the effective tank volume was 500 L, the filling rate was 50%, and continuous flow operation was used. The same aeration rate and stirring power were controlled to ensure oxygen supply and fluidization of the suspended carrier. The test results are shown in Table 2. The thinner the suspended carrier, the shorter the mass transfer distance in its pores, and the better the mass transfer effect. However, as the suspended carrier becomes thinner, its fluidization form in the water becomes more uniform, becoming a regular tumbling motion, further limiting the mass transfer process. As can be seen from Table 2, for the same specifications of suspended carrier, when the thickness becomes 4 mm, its nitrification performance is 1.1 times that of 10 mm. When the suspended carrier is 2 mm, due to the limitation of the fluidization process, its treatment load is only 82% of that of a 4 mm thick suspended carrier. Therefore, a thickness of 4 mm is the optimal parameter.

[0057] Table 2. Influence of suspended carrier thickness on system processing performance

[0058]

[0059] (3) Finally, the study focused on the pore size of the suspended carrier. The pore size of the suspended carrier is the main site for biofilm attachment and growth. On the one hand, the biofilm thickness is related to mass and oxygen transfer; on the other hand, the biofilm also affects the mass and oxygen transfer process. For the MBBR process, under a certain pore size, the thicker the biofilm, the worse the mass transfer effect. Therefore, it is necessary to study the most suitable pore size of the suspended carrier under different matrix conditions. Four specifications with average pore sizes of 3.5 mm, 4.5 mm, 5.5 mm, and 6.5 mm were selected for the experiment (the smaller the pore size of the suspended carrier, the larger the effective specific surface area). The diameter of the suspended carrier was 25 mm, the thickness was 4 mm, and the specific gravity was 1.15 g / cm³. 3 The effective volume of the reaction tank was 500L, with a filling rate of 50%. The test water was the influent from the aerobic tank of a municipal wastewater treatment plant in northern China, with SS controlled below 50mg / L. Experiments were conducted under ammonia nitrogen concentrations of 50mg / L, 20mg / L, and 5mg / L, with sufficient aeration, to verify the optimal suspended carrier pore size that achieves the highest treatment performance under high, medium, and low substrate conditions. The experimental results are shown in Table 3. Table 3 shows that under high substrate conditions, due to sufficient substrate and good mass transfer, a higher biofilm thickness is achieved, thus increasing the impact of suspended carrier pore size on overall treatment performance. When the suspended carrier pore size is 3.5mm, the pores are almost completely blocked by the biofilm, resulting in the lowest treatment performance. At a pore size of 6.5mm, the treatment performance fails to reach its maximum due to the low effective surface area of ​​the carrier. The best treatment performance is achieved with a pore size of 5.5mm. When cultured in medium substrate, the biofilm thickness decreases compared to higher substrate, thus reducing the impact of pore size on treatment performance and increasing its correlation with effective specific surface area. In this case, a pore size of 4.5 mm yields the optimal value. When cultured in low substrate, the biofilm thickness further decreases, and pore size becomes essentially no longer a primary parameter affecting treatment performance. Effective surface area has the greatest influence; smaller pore sizes result in larger effective specific surface areas. Therefore, a pore size of 3.5 mm provides the best treatment effect.

[0060] Table 3. Influence of suspended carrier pore size on system processing performance

[0061]

[0062] Example 3:

[0063] A pilot-scale experiment was conducted to verify the impact of system grading on treatment efficiency. The test water was taken from the influent of the aerobic zone of a wastewater treatment plant in northern China, with ammonia nitrogen at 40 mg / L and SS below 50 mg / L, operating in continuous flow mode. Two operating systems were used: System 1 was a single-stage system, and System 2 was a three-stage system, with the three tanks having the same volume ratio. System 1 and System 2 had the same total tank volume, and used the same suspended carrier and filling rate. The experimental results are shown in Table 4. Table 4 shows that both System 1 and System 2 could ensure stable effluent compliance. However, due to regional limitations, the parameter control of System 1 was relatively simple, requiring overall adjustments if the influent quality and quantity fluctuated. In contrast, System 2, due to its multi-stage setup, offered more flexible control. During actual operation, it was observed that the biofilm thickness decreased progressively from stage one to stage two, the biofilm color became lighter, and the enrichment capacity for nitrifying bacteria also decreased. This is mainly due to the advantages of biofilm-specific enrichment culture. Because the substrate concentration entering the primary reaction tank is higher, the corresponding functional bacteria enrichment capacity is higher, and the biofilm is thicker, resulting in a higher single-stage treatment load compared to System 1. When encountering shocks in water quality and quantity, the impact can be addressed by adjusting relevant parameters in the primary zone, thereby reducing the operational pressure on subsequent secondary and tertiary stages. When primary control is insufficient, secondary and tertiary stages are then adjusted sequentially, making overall control more flexible. Further, the tank volume ratio of System 2 is divided and adjusted to System 3. Based on System 2, the higher treatment efficiency of the primary zone is fully utilized, increasing the tank volume to 50%. Through operational control, it can handle more than 70% of pollutants, achieving the goal of reducing pollutant load. The secondary and tertiary tank volume ratios decrease sequentially, undertaking the task of ensuring compliance.

[0064] Table 4. The impact of reaction zone grading on system operation

[0065]

[0066] Example 4:

[0067] In this embodiment, the primary, secondary, and tertiary stages refer to the primary, secondary, and tertiary reaction tanks, respectively. An experiment was conducted to verify the impact of the aeration method on system operation. The test water was taken from the influent of the aerobic zone of a wastewater treatment plant in northern China, with ammonia nitrogen of 40 mg / L and SS below 50 mg / L. Continuous flow operation was used, and the effluent ammonia nitrogen was set at 1.5 mg / L. The reactor adopted a three-stage system with a tank volume ratio of 5:3:2 for the primary, secondary, and tertiary stages. The experimental results are shown below. Figure 2 And as shown in Table 5. From Figure 2 As shown in Table 5, aeration mode one uses a conventional allocation method based on pool volume, with all systems operating normally and effluent consistently meeting standards. Based on this, the secondary and tertiary aeration stages are shut down, and the primary aeration ratio is adjusted sequentially to 50%, 60%, 70%, and 80%, forming aeration modes two through five. Figure 2 As shown in Table 5, with the increase of primary aeration, the primary treatment performance improves, and the effluent ammonia nitrogen decreases. Furthermore, due to the long gas-liquid contact time of the nanobubbles, the unused nanobubbles in the primary reactor continue to be utilized in the secondary and tertiary reactors. Therefore, in the experiments with aeration methods two through five, although there was no aeration in the secondary and tertiary stages, nitrification still occurred, achieving full utilization of the nanobubbles. However, when the primary aeration increased to 80%, the improvement in primary treatment performance was limited; therefore, a maximum primary aeration rate of 70% of the total gas volume is optimal. Based on this, secondary aeration was added (with tertiary aeration still closed), controlled at 30%, 15%, 10%, and 5% respectively, i.e., aeration methods six through nine. Figure 2 As shown in Table 5, based on aeration mode four, adding secondary aeration further reduces ammonia nitrogen in the effluent. When secondary aeration accounts for 30% of the total air volume, the effluent stably meets the standards. Further reducing secondary aeration to 10% still achieves 1.5 mg / L, but further reducing it to 5% results in ammonia nitrogen exceeding the standard and failing to meet treatment requirements. Therefore, the secondary stage still needs to provide 10%~15% of the air supply. Furthermore, based on primary aeration at 70% and secondary aeration at 10%, tertiary aeration is activated, accounting for 5% of the total air volume, forming aeration mode ten. Based on aeration mode eight, ammonia nitrogen is further reduced to 0.5 mg / L. Therefore, during operation, the tertiary reaction zone prioritizes stability and may be off or only partially activated. Overall, the aeration ratio for each stage is primarily 60%~70% for primary aeration, 10%~15% for secondary aeration, and 0%~5% for tertiary aeration, lower than the calculated total air volume. Energy saving and consumption reduction are further achieved through reactor design and aeration ratio control.

[0068] Table 5. Ammonia nitrogen concentrations in effluent from different functional zones under different aeration methods.

[0069]

[0070] Any parts not mentioned in this invention can be achieved by referring to existing technologies.

[0071] Those skilled in the art should recognize that the above embodiments are only used to illustrate this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of this application should fall within the scope of protection claimed in this application.

Claims

1. A method for operating a high-oxygen-utilization-rate aerobic MBBR system, characterized in that, The steps are as follows: a. Preparing the system to run: The operating system includes a reaction tank, within which a first corridor, a first reaction tank, a second corridor, a second reaction tank, a third corridor, a third reaction tank, and a defoaming tank are sequentially arranged along the water flow direction. Nano-aerators are installed on the bottom surfaces of the first, second, and third corridors, and each nano-aerator is connected to a nano-gas generator. Suspended carriers and agitators are installed in the first, second, and third reaction tanks, and a perforated pipe aerator is installed at the bottom of the defoaming tank. The volume ratio of the first reaction tank, the second reaction tank, and the third reaction tank is 5:3:2, and the first corridor, the second corridor, and the third corridor each account for 10% to 15% of the volume of their respective first reaction tank, second reaction tank, and third reaction tank. The specific gravity of the suspended carrier in each of the three reaction tanks was 1.10~1.20 g / cm³. 3 The thickness of each is 3mm~5mm; the pore size of the suspended carrier in the first reaction tank is 5~6mm, the pore size of the suspended carrier in the second reaction tank is 4~5mm, and the pore size of the suspended carrier in the third reaction tank is 3~4mm. b. The wastewater to be treated enters from the first channel, and the SS in the influent is less than 50 mg / L; the aeration rate of the first channel is greater than that of the second channel, and the aeration rate of the second channel is greater than that of the third channel. The operation method includes the following steps: (1) Normal operation phase: The first, second, and third corridors are supplied with gas normally, and the stirring power density of the first reaction tank is controlled at 10~12W / m. 3 The stirring power density of the second and third reaction tanks is 7~10 W / m³. 3 ; (2) High-intensity hydraulic shear stage: The first, second, and third corridors are supplied with gas normally, and the stirring power density of the first reaction tank is controlled at 17~20W / m. 3 The stirring power density of the second reaction tank is 12~15W / m³. 3 The stirring power density of the third reaction tank is 7~10 W / m³. 3 ; (3) For the reaction tank with the core function of removing organic matter, the strong hydraulic shear stage is started once every 10 to 15 days, and each time it is started for 2 to 3 hours; for the reaction tank with the core function of removing ammonia nitrogen, the strong hydraulic shear stage is started once every 20 to 25 days, and each time it is started for 1 to 2 hours; the air supply of the first corridor is 60% to 70% of the theoretical value of the overall aeration of the reaction tank, the air supply of the second corridor is 10% to 15% of the theoretical value of the overall aeration of the reaction tank, and the air supply of the third corridor is 0% to 5% of the theoretical value of the overall aeration of the reaction tank.

2. The operation method of a high oxygen utilization aerobic MBBR system according to claim 1, characterized in that: The pore size of the nano aerator is 100nm~500nm.

3. The operation method of a high oxygen utilization aerobic MBBR system according to claim 1, characterized in that: Interception screens are installed at the outlets between the first corridor and the first reaction tank, the first reaction tank and the second corridor, the second corridor and the second reaction tank, the second reaction tank and the third corridor, the third corridor and the third reaction tank, and the third reaction tank and the defoaming tank.

4. The operation method of a high oxygen utilization aerobic MBBR system according to claim 1, characterized in that: The agitator is a variable frequency agitator.

5. The operation method of a high oxygen utilization aerobic MBBR system according to claim 1, characterized in that: The specific gravity of the suspended carriers was 1.15 g / cm³. 3 The thickness of each is 4mm.

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