Operation method of aerobic MBBR (Moving Bed Biofilm Reactor) system with high oxygen utilization rate

Abstract

The invention discloses an operation method of an aerobic MBBR (Moving Bed Biofilm Reactor) system with a high oxygen utilization rate, and belongs to the technical field of water treatment. The operation system comprises a reaction tank, a first gallery, a first reaction tank, a second gallery, a second reaction tank, a third gallery, a third reaction tank and a defoaming tank are sequentially arranged in the reaction tank in the water flow direction, and nano aerators are arranged on the bottom surfaces in the first gallery, the second gallery and the third gallery. The nano aerators are respectively connected with a nano gas generating device; suspended carriers and stirrers are arranged in the first reaction tank, the second reaction tank and the third reaction tank; a perforated pipe aerator is mounted at the bottom of the defoaming tank; sewage to be treated enters from the first gallery; the aeration rate of the first gallery is greater than that of the second gallery, and the aeration rate of the second gallery is greater than that of the third gallery. According to the invention, the utilization rate of nano bubble oxygen is higher, the energy consumption is further reduced, the removal rate of oxygen-consuming pollutants is high, and the treatment is stable.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to an operation method of an aerobic MBBR system with high oxygen utilization rate. Background Art

[0002] The microbial essence of the moving bed biofilm reactor (MBBR) is the biofilm method, and its advantage lies in its strong ability to enrich functional bacteria. Although it improves the biochemical treatment effect as a whole, the macroscopic effect is also related to mass transfer and oxygen transfer. Limited by oxygen mass transfer, the treatment load of the biofilm fluctuates greatly. In order to fully release the activity of microorganisms, a large amount of oxygen is often required in actual engineering applications. The traditional aeration method is mainly microporous aeration or perforated aeration. On the one hand, the bubbles produced are large and the gas-liquid contact area is small. On the other hand, the gas rising velocity is fast and the gas-liquid contact time is short, which results in a high aeration waste overall. Nanobubbles are suitable for MBBR process oxygenation facilities because of their advantages such as large relative area and slow rising speed. Not only can it improve oxygen utilization and reduce energy consumption, but also because of the enhanced oxygen transfer effect, it can also achieve higher treatment effects.

[0003] The research reports in the prior art are as follows:

[0004] CN 106186558A discloses a nanobubble efficient oxygen supply suspended carrier flow biochemical bed sewage treatment system, including a grille, an anaerobic tank, an anoxic tank, an MBBR nanobubble bioreactor and a secondary sedimentation tank. A high specific surface area suspended carrier suitable for the attachment and reproduction of microbial strains is placed in the MBBR nanobubble bioreactor, and the MBBR nanobubble bioreactor is connected to a nanobubble machine with an oxygen gas source, which is responsible for transporting nanobubbles into the MBBR nanobubble bioreactor to form a high-density nanobubble water body. It combines nanobubble technology with suspended carrier flow biochemical bed technology to form a brand-new sewage treatment system and process, eliminating the shortcomings of existing activated sludge systems such as high energy consumption and aeration. The main technical problems of the treatment device and treatment process are that the system is only a combination of nanobubbles and suspended carrier flow biochemical bed processes: ① Its beneficial effects are only reflected in nano aeration, and the beneficial effects of the combination of nano aeration and suspended carrier flow biochemical bed processes are not reflected. The beneficial effects of the high volume load of the system reflected in this document are all brought by the biofilm process itself, which has nothing to do with nano aeration. ② During operation, the problem of biofilm mass transfer and oxygen transfer under nano-aeration was not fully considered, which easily caused biofilm blockage and reduced system performance. ③ The reactor structure setting failed to effectively utilize the advantage of the long residence time of nanobubbles and failed to further exert the process advantages.

[0005] It can be seen that there are still many problems in the application of micro-nano aeration in the field of water treatment, especially for process operation, and the existing technology needs to be further improved. Summary of the invention

[0006] The object of the present invention is to provide an operation method of an aerobic MBBR system with high oxygen utilization rate. Compared with conventional methods, the method has high removal rate of organic matter and ammonia nitrogen and stable treatment effect.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for operating a high oxygen utilization rate aerobic MBBR system comprises the following steps in sequence:

[0009] a. Prepare to run the system

[0010] The operation system comprises a reaction pool, in which a first gallery, a first reaction pool, a second gallery, a second reaction pool, a third gallery, a third reaction pool and a defoaming pool are sequentially arranged along the water flow direction, and nano aerators are arranged on the bottom surfaces of the first gallery, the second gallery and the third gallery, and the nano aerators are respectively connected to nano gas generating devices; a suspension carrier and a stirrer are arranged in the first reaction pool, the second reaction pool and the third reaction pool, and a perforated tube aerator is installed at the bottom of the defoaming pool;

[0011] The volume ratio of the first reaction pool, the second reaction pool, and the third reaction pool is 5:3:2. The first corridor, the second corridor, and the third corridor account for 10% to 15% of the volume of the first reaction pool, the second reaction pool, and the third reaction pool, respectively;

[0012] The specific gravity of the suspended carriers in the three reaction tanks is 1.10-1.20 g / cm 3 , the thickness is 3mm~5mm; the pore size of the suspension carrier located in the first reaction tank is 5~6mm, the pore size of the suspension carrier located in the second reaction tank is 4~5mm, and the pore size of the suspension carrier located in the third reaction tank is 3~4mm;

[0013] b. The sewage to be treated enters from the first corridor, and the inlet SS is lower than 50 mg / L; the aeration volume of the first corridor is greater than that of the second corridor, and the aeration volume of the second corridor is greater than that of the third corridor;

[0014] The operation method includes the following steps:

[0015] (1) Normal operation stage: The first, second and third galleries are supplied with gas normally, and the stirring power density of the first reaction pool is controlled to be 10-12 W / m 3 The stirring power density of the second reaction tank and the third reaction tank is 7-10W / m3 ;

[0016] (2) Strong hydraulic shear stage: The first, second and third galleries are supplied with air normally, and the stirring power density of the first reaction tank is controlled to be 17-20 W / m 3 The stirring power density of the second reaction tank is 12-15 W / m 3 The stirring power density of the third reaction tank is 7-10W / m 3 ;

[0017] (3) For reaction pools whose core is to remove organic matter, the strong hydraulic shear stage is started every 10 to 15 days, and each time it is turned on for 2 to 3 hours; for reaction pools whose core is to remove ammonia nitrogen, the strong hydraulic shear stage is started every 20 to 25 days, and each time it is turned on for 1 to 2 hours.

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

[0019] In the above-mentioned operation method of a high oxygen utilization rate aerobic MBBR system, the pore size of the nano aerator is 100nm to 500nm.

[0020] In the above-mentioned operation method of the high oxygen utilization rate aerobic MBBR system, interception screens are provided at the water outlets between the first gallery and the first reaction tank, the first reaction tank and the second gallery, the second gallery and the second reaction tank, the second reaction tank and the third gallery, the third gallery and the third reaction tank, and the third reaction tank and the defoaming tank.

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

[0022] In the above-mentioned method for operating a high oxygen utilization rate aerobic MBBR system, the agitator is a variable frequency agitator.

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

[0024] (1) The present invention proposes an operation method of an aerobic MBBR system with high oxygen utilization rate, wherein the reaction pools are sequentially arranged according to the water flow direction into a first gallery, a first reaction pool, a second gallery, a second reaction pool, a third gallery, a third reaction pool and a defoaming pool, the aeration volume of the first gallery is greater than that of the second gallery, and the aeration volume of the second gallery is greater than that of the third gallery; the purpose of such design is to improve the treatment efficiency of the first reaction pool, and the unused nanobubbles enter the subsequent reaction pools. Through experimental research, when the air supply volume of the first gallery is 60% to 70% of the theoretical value of the overall aeration volume, the mass transfer can be enhanced and the treatment efficiency can be improved.

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

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

[0027] (4) The present invention adopts graded treatment, which is efficient and controllable. Based on the advantages of MBBR process and long-term residence of nanobubbles, graded treatment and gradient reduction of aeration are adopted to extend the gas-liquid contact time and reduce the aeration volume. At the same time, graded treatment reduces the complexity of installation and control of the agitator based on different fluidization shear force control.

[0028] (5) The reactor layout realizes the complete separation of the nano aerator and the suspended carrier, protecting the nano aerator from the influence of the suspended carrier and improving the service life. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0031] Figure 2 This is the change diagram of effluent ammonia nitrogen concentration in each functional area under different aeration modes;

[0032] In the figure: 1-nano aerator; 2-nano gas generating device; 3-agitator; 4-water outlet intercepting screen; 5-perforated tube 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, water inlet, 14, water outlet. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application.

[0034] It is understandable that the connection relationship described in this application refers to direct or indirect connection. For example, the connection between A and B can be either 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 and C can be directly connected, and C and B can be directly connected, so that A and B are connected through C. It is also understandable that the "A connects 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, words such as "first" and "second" are only used to distinguish different objects, and do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit differences. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0036] The main technical concept of the present invention is to make full use of the characteristics of the biofilm method and the advantages of nanobubbles to achieve a synchronous energy-saving and efficient pollution removal process. The treatment effect of the biofilm method is closely related to mass transfer and oxygen transfer. The improvement of mass transfer and oxygen transfer capacity means the improvement of the treatment effect of the biofilm method, thereby reducing the land occupation of sewage treatment. Nanobubbles solve the problem of oxygen transfer, but fail to solve the mass transfer that affects the efficient treatment performance of MBBR, that is, the fluidization problem. At the same time, the residence time of nanobubbles is long, and extending the gas-liquid contact time will further improve the oxygen utilization rate and reduce the oxygenation energy consumption. Therefore, the starting point of the present invention is how to achieve good mass transfer and fluidization, how to extend the gas-liquid contact time, and achieve efficient pollutant treatment and energy saving and consumption reduction.

[0037] like Figure 1As shown, the operating system of the present invention includes a reaction pool, which is divided into a first corridor 10, a first reaction pool 6, a second corridor 11, a second reaction pool 7, a third corridor 12, a third reaction pool 8 and a defoaming pool 9 in sequence according to the water inlet direction. A nano aerator 1 is arranged on the bottom surface of the first corridor 10, the second corridor 11 and the third corridor 12, and nano bubbles are provided into the corridor through the nano aerator, and then enter the reaction pool adjacent to the corridor. The nano aerator is respectively connected to a nano gas generating device 2; a suspension carrier and a stirrer 3 are arranged in the first reaction pool, the second reaction pool and the third reaction pool, and a perforated tube aerator 5 is installed at the bottom of the defoaming pool 9.

[0038] The volume ratio of the first reaction tank, the second reaction tank and the third reaction tank is 5:3:2. The first corridor, the second corridor and the third corridor account for 10% to 15% of the volume of the first reaction tank, the second reaction tank and the third reaction tank respectively; such a setting can improve water treatment efficiency, increase the actual gas-liquid contact time of the first aeration, improve oxygen utilization, and reduce the second and third aeration volumes and energy consumption.

[0039] The specific gravity of the suspended carriers in the three reaction tanks is 1.10-1.20 g / cm 3 , the thickness is 3mm~5mm; the pore size of the suspended carrier located in the first reaction tank is 5~6mm, the pore size of the suspended carrier located in the second reaction tank is 4~5mm, and the pore size of the suspended carrier located in the third reaction tank is 3~4mm; the characteristics of the suspended carrier match the nanobubbles, and the water matrix gradually decreases from the first reaction tank to the third reaction tank, the mass transfer weakens, and the thickness of the biofilm will be thin. Therefore, the pore size from the first reaction tank to the third reaction tank decreases, increasing the effective surface area, thereby ensuring the overall pollution treatment volume load.

[0040] The aperture of the nano aerator is 100nm-500nm; interception screens are arranged at the water 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 operating method of the above system is specifically as follows:

[0042] The sewage to be treated enters from the first corridor, and the inlet SS is lower than 50 mg / L; the aeration volume of the first corridor is greater than that of the second corridor, and the aeration volume of the second corridor is greater than that of the third corridor;

[0043] The operation method includes the following steps:

[0044] (1) Normal operation stage: The first, second and third galleries are supplied with gas normally, and the stirring power density of the first reaction pool is controlled to be 10-12 W / m 3The stirring power density of the second reaction tank and the third reaction tank is 7-10W / m 3 ;

[0045] (2) Strong hydraulic shear stage: The first, second and third galleries are supplied with air normally, and the stirring power density of the first reaction tank is controlled to be 17-20 W / m 3 The stirring power density of the second reaction tank is 12-15 W / m 3 The stirring power density of the third reaction tank is 7-10W / m 3 ;

[0046] (3) For reaction pools whose core is to remove organic matter, the strong hydraulic shear stage is started every 10 to 15 days, and each time it is turned on for 2 to 3 hours; for reaction pools whose core is to remove ammonia nitrogen, the strong hydraulic shear stage is started every 20 to 25 days, and each time it is turned on for 1 to 2 hours.

[0047] The present invention will be further described below in conjunction with specific embodiments:

[0048] Embodiment 1:

[0049] In order to verify the effect of SS in the operating system on nano aeration, a comparative test was conducted. The effective tank capacity of the operating system is 5m 3 The influent was the aerobic pool in a municipal sewage plant in the north. The SS was controlled at 30mg / L, 50mg / L, 80mg / L, and 100mg / L. The system was aerobic and the same air volume was introduced. A pressure gauge was connected to one end of the nano aerator. The system was operated continuously for a total of 6 months.

[0050] During the operation of each reactor, when SS was controlled at 30mg / L and 50mg / L, the long-term operation pressure gauge showed a basically stable state between 2.10 and 2.15Mpa. When SS was increased to 80mg / L, the pressure gauge showed a continuous increase from the 159th day. After 6 months of operation, the final pressure was 2.18Mpa. When SS was increased to 100mg / L, the pressure increase time was advanced to the 135th day, and the final pressure was 2.22Mpa. The main reason for the pressure increase is that SS particles blocked the aperture of the nano aerator, thereby increasing the aeration resistance. Compared with the engineering operation, the test time is relatively short, but from the results, when SS is greater than 80mg / L, the operation of the system has shown an impact on the nano aerator, so the actual control should ensure that the system inlet SS is below 50mg / L.

[0051] Embodiment 2:

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

[0053] (1) First, the specific gravity of the suspension carrier. The specific gravity of the suspension carrier selected in the experiment is 0.96 g / cm 3 , 1.05g / cm 3 , 1.15g / cm 3 , 1.25g / cm 3 Four specifications all use cylindrical suspended carriers with a diameter of 25mm, a thickness of 10mm, and an average pore size of 4.5mm. The test water is the inlet water of the aerobic pool of a municipal sewage plant in the north. The SS is controlled below 50mg / L, the ammonia nitrogen is 40mg / L, the effective pool capacity of the MBBR reaction pool is 500L, the filling rate is 50%, and the continuous flow operation is controlled to ensure the oxygen supply and fluidization of the suspended carrier. The test results are shown in Table 1. It can be seen from Table 1 that the influence of the specific gravity of the suspended carrier on the operating system is mainly fluidization, and fluidization indirectly affects the biofilm and treatment effect. The better the fluidization, the more uniform the distribution of the suspended carrier, the better the biofilm, and the higher the treatment performance. For the nano aeration system, the nano bubbles will attach to the suspended carrier during the rising process, thereby increasing the buoyancy of the suspended carrier, which is equivalent to reducing a part of the specific gravity. Therefore, the specific gravity of the suspended carrier itself is relatively large, 1.15g / cm 3 The suspended carrier is suitable for nano aeration system.

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

[0055]

[0056] (2) Secondly, for the study of the thickness of the suspension carrier, three thicknesses of suspension carriers were selected for the experiment: 10 mm, 4 mm, and 2 mm, with a specific gravity of 1.15 g / cm 3 , diameter is 25mm, average pore size is 4.5mm. The test water is the inlet water of aerobic pool of a municipal sewage plant in the north. SS is controlled below 50mg / L, ammonia nitrogen is 40mg / L, the effective pool capacity of the reaction pool is 500L, the filling rate is 50%, continuous flow operation, and the same aeration volume and stirring power are controlled to ensure oxygen supply and fluidization of suspended carriers. The test results are shown in Table 2. The thinner the suspended carrier, the shorter the mass transfer distance in its pore size and the better the mass transfer effect. However, as the suspended carrier becomes thinner, its fluidization form in the water becomes single and becomes a regular flip, which further limits the mass transfer process. It can be seen from Table 2 that for the same specification of suspended carrier, when the thickness becomes 4mm, its nitrification performance is 1.1 times that of 10mm. When the suspended carrier becomes 2mm, due to the limitation of the fluidization process, its treatment load is only 82% of the suspended carrier thickness of 4mm. Therefore, the thickness of 4mm is the best parameter.

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

[0058]

[0059]

[0060] (3) The last part is the study on the pore size of the suspended carrier. The pore size of the suspended carrier is the main place for the biofilm to attach and grow. On the one hand, the thickness of the biofilm is related to mass transfer and oxygen transfer; on the other hand, the biofilm also affects the mass transfer and oxygen transfer process. For the MBBR process, when the pore size is constant, 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. The experiment selected four specifications with an average pore size of 3.5mm, 4.5mm, 5.5mm, and 6.5mm (the smaller the pore size of the suspended carrier also means a larger effective specific surface area). The diameter of the suspended carrier is 25mm, the thickness is 4mm, and the specific gravity is 1.15g / cm 3 , the effective tank capacity of the reaction tank is 500L, and the filling rate is 50%. The test water is the influent of the aerobic tank of a municipal sewage plant in the north. The SS is controlled to be lower than 50mg / L. The test is carried out under the conditions of ammonia nitrogen concentration of 50mg / L, 20mg / L, and 5mg / L, respectively. Sufficient aeration is given to verify the optimal suspended carrier pore size that can achieve the highest treatment performance under high, medium, and low substrate conditions. The test results are shown in Table 3. It can be seen from Table 3 that when it is in high substrate culture, due to sufficient substrate and good mass transfer effect, it has a higher biofilm thickness, so the suspended carrier pore size has a higher impact on the overall treatment performance. When the suspended carrier pore size is 3.5mm, the suspended carrier pore size is almost "blocked" by the biofilm, so the treatment performance is the lowest. When the pore size is 6.5mm, the treatment performance fails to reach the maximum value due to the low effective surface area of ​​the carrier. When the pore size is 5.5mm, the treatment performance is the best. When cultured in medium matrix, the biofilm thickness is reduced compared to high matrix, so the effect of pore size on treatment performance is weakened, and the correlation with effective specific surface area increases. At this time, the best value is obtained when the pore size is 4.5mm. When cultured in low matrix, the biofilm thickness is further reduced. At this time, the pore size is basically not the main parameter affecting the treatment performance. The effective surface area has the largest effect. The smaller the pore size, the larger the effective specific surface area. Therefore, the treatment effect is best when the pore size is 3.5mm.

[0061] Table 3 Effect of suspended carrier pore size on system processing performance

[0062]

[0063] Embodiment 3:

[0064] The pilot test was used to verify the effect of system classification on the treatment effect. The test water was taken from the influent of the aerobic zone of a sewage plant in the north. The ammonia nitrogen was 40 mg / L and the SS was less than 50 mg / L. It was operated in a continuous flow. Two operating systems were used. System 1 was a single-stage system and system 2 was a three-stage system. The three tank volumes had the same proportion. The total tank volume of system 1 and system 2 was the same. The suspended carriers and filling rates used were the same. The test results are shown in Table 4. As can be seen from Table 4, both system 1 and system 2 can ensure that the effluent meets the standard stably. However, due to the region, the parameter control of system 1 is relatively simple. If the influent water quality and water volume fluctuate, an overall adjustment is required. In contrast, system 2 has more flexible control due to its multi-stage setting. It was found from the actual operation process that the thickness of the biofilms of the first, second and third levels decreased step by step, the color of the biofilms became lighter and lighter, and the enrichment capacity of nitrifying bacteria became lower and lower. This is mainly due to the advantages of biofilm-specific enrichment culture. Since the matrix concentration entering the primary reaction pool is high, the corresponding functional bacteria enrichment capacity is higher and the biofilm is thicker, so the single-stage treatment load is higher than that of system one. When encountering water quality and quantity shocks, the shocks can be dealt with by adjusting the relevant parameters of the primary area, thereby reducing the subsequent secondary and tertiary operation pressures. When the primary regulation is difficult to solve, the secondary and tertiary levels are adjusted in turn, and the overall regulation is more flexible. The pool capacity ratio of system two is further divided and adjusted to system three. On the basis of system two, the more efficient treatment performance of the primary area is fully utilized to increase the pool capacity to 50%. Through operation and regulation, it can bear the treatment of more than 70% of pollutants at most, achieving the goal of reducing pollutant loads. The proportion of the secondary and tertiary pools is reduced in turn, and they undertake the task of ensuring compliance.

[0065] Table 4 Effect of reaction zone classification on system operation

[0066]

[0067] Embodiment 4:

[0068] The first level, second level, and third level mentioned in this embodiment are the first level reaction tank, the second level reaction tank, and the third level reaction tank, respectively. The effect of aeration mode on system operation was verified by experiment. The test water was taken from the inlet of aerobic zone of a sewage treatment plant in the north. The ammonia nitrogen was 40 mg / L and SS was lower than 50 mg / L. The continuous flow was operated and the effluent ammonia nitrogen was in accordance with the standard of 1.5 mg / L. The reactor adopts a three-stage system, and the ratio of the first level, second level, and third level is 5:3:2. See the test results. Figure 2 and as shown in Table 5. Figure 2 As can be seen from Table 5, aeration method 1 adopts the conventional mode of allocating water according to the proportion of pool capacity, each system operates normally, and the effluent is stable and meets the standard. On this basis, the secondary and tertiary aeration are closed, and the primary aeration ratio is adjusted to 50%, 60%, 70%, and 80% in turn, forming aeration methods 2 to 5. Figure 2 It can be seen from Table 5 that with the increase of the first-stage aeration volume, the first-stage treatment performance is improved, the effluent ammonia nitrogen is reduced, and because the nanobubbles have a long gas-liquid contact time, the unused nanobubbles in the first-stage reaction pool continue to be used after entering the second and third-stage reaction pools. Therefore, in the test process of aeration methods two to five, although there is no aeration in the second and third stages, there is still a nitrification process, and the nanobubbles are fully utilized. However, when the first-stage aeration is increased to 80%, the improvement of the first-stage treatment performance is limited, so the maximum first-stage aeration volume is 70% of the total gas volume. On this basis, the second-stage aeration is added (the third-stage aeration is still closed), and the control is 30%, 15%, 10%, and 5%, respectively, that is, aeration methods six to nine. From Figure 2 As can be seen from Table 5, on the basis of aeration mode 4, the addition of secondary aeration further reduces the secondary effluent ammonia nitrogen. When the secondary aeration is 30% of the total air volume, the effluent is stable and meets the standard. When the secondary aeration is further reduced to 10%, it can still reach 1.5 mg / L. When it is further reduced to 5%, the effluent ammonia nitrogen exceeds the standard and fails to meet the treatment requirements, so the secondary still needs to provide 10% to 15% of the air supply. Further, on the basis of the primary aeration volume of 70% and the secondary aeration volume of 10%, the third-level aeration is turned on, and the aeration volume accounts for 5% of the total air volume, forming aeration mode 10. On the basis of aeration mode 8, the ammonia nitrogen is further reduced to 0.5 mg / L, so the third-level reaction zone is mainly used to ensure stability during operation, and it can be turned off or turned on in small quantities. On the whole, the aeration ratio of each level is mainly 60% to 70% for the first level, 10% to 15% for the second level, and 0% to 5% for the third level, which is lower than the calculated total air volume. Energy saving and consumption reduction can be further achieved through reactor design and control of aeration ratio.

[0069] Table 5 Ammonia nitrogen concentration in effluent from each functional area under different aeration modes

[0070]

[0071] Parts not described in the present invention can be implemented by referring to the existing technology.

[0072] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present application and are not intended to be limiting of the present application. As long as they are within the spirit and scope of the present application, appropriate changes and modifications to the above embodiments should fall within the scope of protection claimed in the present application.

Claims

1. A method for operating a high oxygen utilization rate aerobic MBBR system, characterized in that: The following steps are included in sequence: a. Prepare to run the system The operation system comprises a reaction pool, in which a first gallery, a first reaction pool, a second gallery, a second reaction pool, a third gallery, a third reaction pool and a defoaming pool are sequentially arranged along the water flow direction, and nano aerators are arranged on the bottom surfaces of the first gallery, the second gallery and the third gallery, and the nano aerators are respectively connected to nano gas generating devices; a suspension carrier and a stirrer are arranged in the first reaction pool, the second reaction pool and the third reaction pool, and a perforated tube aerator is installed at the bottom of the defoaming pool; The volume ratio of the first reaction pool, the second reaction pool, and the third reaction pool is 5:3:2, and the first corridor, the second corridor, and the third corridor account for 10% to 15% of the volume of the first reaction pool, the second reaction pool, and the third reaction pool, respectively; The specific gravity of the suspended carriers in the three reaction tanks is 1.10-1.20 g / cm 3 , the thickness is 3mm~5mm; the pore size of the suspension carrier located in the first reaction tank is 5~6mm, the pore size of the suspension carrier located in the second reaction tank is 4~5mm, and the pore size of the suspension carrier located in the third reaction tank is 3~4mm; b. The sewage to be treated enters from the first corridor, and the inlet SS is lower than 50 mg / L; the aeration volume of the first corridor is greater than that of the second corridor, and the aeration volume of the second corridor is greater than that of the third corridor; The operation method includes the following steps: (1) Normal operation stage: The first, second and third galleries are supplied with gas normally, and the stirring power density of the first reaction pool is controlled to be 10-12 W / m 3 The stirring power density of the second reaction tank and the third reaction tank is 7-10W / m 3 ; (2) Strong hydraulic shear stage: The first, second and third galleries are supplied with air normally, and the stirring power density of the first reaction tank is controlled to be 17-20 W / m 3 The stirring power density of the second reaction tank is 12-15 W / m 3 The stirring power density of the third reaction tank is 7-10W / m 3 ; (3) For reaction pools whose core is to remove organic matter, the strong hydraulic shear stage is started every 10 to 15 days, and each time it is turned on for 2 to 3 hours; for reaction pools whose core is to remove ammonia nitrogen, the strong hydraulic shear stage is started every 20 to 25 days, and each time it is turned on for 1 to 2 hours.

2. The method for operating a high oxygen utilization rate aerobic MBBR system according to claim 1, characterized in that: The air supply of the first corridor is 60% to 70% of the theoretical value of the overall aeration volume of the reaction tank, the air supply of the second corridor is 10% to 15% of the theoretical value of the overall aeration volume of the reaction tank, and the air supply of the third corridor is 0% to 5% of the theoretical value of the overall aeration volume of the reaction tank.

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

4. The method for operating a high oxygen utilization rate aerobic MBBR system according to claim 1, characterized in that: Intercepting screens are provided at the water 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.

5. The method for operating a high oxygen utilization rate aerobic MBBR system according to claim 1, characterized in that: The stirrer is a variable frequency stirrer.

6. The method for operating a high oxygen utilization rate aerobic MBBR system according to claim 1, characterized in that: The specific gravity of the suspended carrier is 1.15g / cm 3 , the thickness is 4mm.

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