Aerobic granular sludge culture method based on micro-nano aeration technology

Abstract

The invention discloses an aerobic granular sludge culture method based on a micro-nano aeration technology, and belongs to the technical field of water treatment. According to the invention, micro-nano aeration is used, so that the oxygen transfer rate in the aerobic granular sludge reactor is 2.1 times of that of a conventional aeration group, the generated hydroxyl radicals are 2.6 times of that of the conventional aeration group, the final removal efficiencies of ammonia nitrogen, total nitrogen and COD (Chemical Oxygen Demand) can respectively reach 98%, 85% and 97%, the denitrification performance is excellent, the treatment period is shortened by 1 hour, and the treatment cost is reduced. After the aeration time is shortened, 28% of aeration energy consumption is saved. Micro-nano aeration not only is beneficial to culture and domestication of aerobic granular sludge and promotes removal of pollutants, but also improves the energy utilization efficiency.

Description

Technical Field

[0001] The invention relates to an aerobic granular sludge cultivation method based on micro-nano aeration technology, belonging to the technical field of water treatment. Background Art

[0002] In recent years, aerobic granular sludge has been widely studied as an alternative technology to the activated sludge process and has been applied in a certain scale of engineering. Compared with flocculent sludge, aerobic granular sludge has a faster sedimentation rate due to its dense biological structure, and since there is no need to set up a secondary sedimentation tank, it effectively reduces the floor space of the sewage treatment process. At present, aerobic granular sludge processes often rely on sequencing batch reactors to operate, enabling them to operate at high biomass concentrations, improving their adaptability to high COD and toxic and hazardous substance shocks. In addition, aerobic granular sludge technology can simultaneously carry out nitrification and denitrification, which can reduce the use of recirculation pump systems in traditional denitrification treatment processes, thereby reducing operating costs.

[0003] In the granulation process of flocculent sludge, aeration and oxygen mass transfer rate are two key factors for regulating the performance of aerobic granular sludge process system. However, due to the low solubility of oxygen in the water phase and the poor oxygen transfer efficiency caused by the traditional aeration mode currently used, a large amount of aeration is required to maintain a high dissolved oxygen level in the aerobic granular sludge process, resulting in extremely high aeration energy consumption in sewage treatment plants (accounting for about 50-70% of the total energy consumption). Micro-nano aeration technology has high internal pressure and stability of the micro-nano bubbles themselves, so that the concentration of dissolved gas in the water phase can be higher than the corresponding gas saturation concentration, which can significantly improve the gas dissolution and gas-liquid mass transfer efficiency. Compared with the current traditional aeration system that produces medium and large bubbles, the improvement of oxygen mass transfer under micro-nano aeration conditions may reduce the demand for aeration rate and energy consumption of activated sludge. In addition, studies have shown that the high oxygen transfer capacity of micro-nano bubbles can stimulate aerobic bacteria and their metabolic activity, thereby promoting the removal of organic matter and nutrients and improving the performance of aerobic granular sludge processes. Based on the above properties, micro-nano bubbles have received great attention in environmental applications in recent years.

[0004] At present, in the prior art, CN 116589079 A discloses a method for cultivating aerobic granular sludge using micro-nano bubbles and its application method. The aerobic granular sludge is cultivated by using nano bubbles to provide oxygen for a continuous flow reactor. The dissolved oxygen utilization rate is high, and the formed granular sludge is stable and has excellent performance. However, the reactor used is a continuous flow reactor, and no research has been made on the cultivation of sequencing batch reactors. Compared with continuous flow reactors, sequencing batch reactors have more mature and extensive application cases. Therefore, it is necessary to develop an aerobic granular sludge cultivation method using micro-nano aeration for sequencing batch reactors. Summary of the invention

[0005] Technical issues

[0006] In the traditional aeration mode, the cultivation of aerobic granular sludge not only takes a long time, but also requires extremely high aeration energy consumption. Compared with the conventional aeration mode, micro-nano aeration has a higher oxygen mass transfer efficiency and continuously produces hydroxyl free radicals, which can not only promote the growth of aerobic granular sludge and the removal of pollutants, but also save costs and improve energy efficiency. However, there is no technology for applying micro-nano aeration in sequencing batch reactors.

[0007] Technical Solution

[0008] The present invention provides an aerobic granular sludge cultivation method based on micro-nano aeration technology, and the aerobic granular sludge cultivation method specifically comprises the following steps:

[0009] (1) A sequencing batch reactor is used, and an aeration device is arranged at the bottom of the reactor to control the aeration rate to be 1 to 5 L / min; the aeration device is an aeration device with a 0.2 to 0.3 μm fine aeration head, and the air bubble particle size generated is 1 to 100 μm;

[0010] (2) Inoculating sludge into a sequencing batch reactor and starting to operate the reactor, wherein in one operation cycle, water is introduced for 3 to 7 minutes, aeration is performed for 200 to 205 minutes, sedimentation is performed for 10 to 20 minutes, drainage is performed for 3 to 7 minutes, and the reactor is left idle for 5 to 15 minutes; after the reactor is stably operated, the aeration time is adjusted to 210 to 215 minutes, the sedimentation time is adjusted to 5 to 7 minutes, and the drainage ratio is 55 to 65%;

[0011] (3) After culturing for 25 to 35 days according to the operation cycle of step (2), the operation cycle is adjusted to: water intake for 3 to 7 minutes, aeration for 150 to 160 minutes, sedimentation for 3 to 7 minutes, drainage for 3 to 7 minutes, and drainage ratio of 55 to 65% to obtain aerobic granular sludge.

[0012] Furthermore, the sequencing batch reactor in step (1) can be a cylindrical sequencing batch reactor; if a cylindrical sequencing batch reactor is selected, its height-to-diameter ratio is 8 to 10:1 and its effective volume is 4 to 8 L.

[0013] Furthermore, the aeration rate in step (1) is 1 to 3 L / min.

[0014] Furthermore, the sludge in step (2) is taken from sewage treatment plant A 2 / O process aerobic tank activated sludge.

[0015] Furthermore, in step (2), the MLSS of the inoculated sludge is 3 to 7 g / L.

[0016] Furthermore, in step (2), NH4 +-N concentration is 30~50mg / L, TN concentration is 70~90mg / L, and COD concentration is 800~1200mg / L.

[0017] Specifically, the composition of the influent in step (2) is as follows: 400mg / L CH3COONa, 1000mg / LCH3CH2COONa, 248mg / L NH4Cl, 29.25mg / L KH2PO4, 37.41mg / L K2HPO4, 97mg / L MgSO4, 75mg / LCaCl2, 10mg / L EDTA and 0.05mL trace element solution per liter of influent; the composition of the trace element solution is as follows: 1.5mg / LFeCl3·6H2O, 0.15mg / L H3BO3, 0.03mg / L CuSO4·5H2O, 0.03mg / L KI, 0.12mg / LMnCl2·4H2O, 0.058mg / L ZnCl2, 0.15mg / L CoCl2·6H2O, 0.06mg / L Na2MoO4·2H2O.

[0018] Furthermore, the periodic adjustment in step (3) is specifically as follows: water intake for 5 minutes, aeration for 155 minutes, sedimentation for 5 minutes, and drainage for 5 minutes.

[0019] The present invention provides aerobic granular sludge cultivated according to the above method.

[0020] The aerobic granular sludge provided by the present invention is used in the field of sewage treatment or environmental protection.

[0021] Beneficial Effects

[0022] Time-saving and efficient: The present invention found that the oxygen transfer rate in the micro-nano aeration reactor is 0.2373 kg / m 3 / h, which is 2.1 times that of the conventional aeration group, and can produce 1.75×10 -11 The removal efficiency of hydroxyl radicals, ammonia nitrogen, total nitrogen and COD of Ms can be stabilized at high treatment levels of 98%, 85% and 97% respectively; the aeration time is shortened by 60 minutes under the premise of ensuring the treatment efficiency, and 28% of the aeration energy consumption can be saved in each operation cycle compared with conventional aeration. Micro-nano aeration in a sequencing batch reactor is not only conducive to the cultivation and domestication of aerobic granular sludge, but also promotes the removal of pollutants, and improves energy efficiency, reducing cultivation time and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : Schematic diagram of aerobic granular sludge device.

[0024] Figure 2 :Fitting ln(C S-C) Linear regression curve of the time; Figure 2 a is the fitting ln(C S -C) Linear regression curve of time; Figure 2 b is the comparison of oxygen transfer rate.

[0025] Figure 3 : ·OH exposure under two aeration modes.

[0026] Figure 4 : Pollutant removal effect; Figure 4 a is the removal effect of conventional aeration; Figure 4 b is the removal effect of micro-nano aeration. DETAILED DESCRIPTION

[0027] Example 1: Cultivation of aerobic granular sludge

[0028] The device uses a cylindrical sequencing batch reactor with a H / D ratio of 10:1. An aeration device is set at the bottom of the reactor with an effective volume of 4L. A rotor flowmeter is used to control the aeration volume at 2L / min during the oxygen flushing stage. The reactor device is as shown in the attached Figure 1 The aeration device is a 0.22 μm fine aeration head, and the bubble size produced is about 100 μm, which belongs to micro-nano bubbles. The inoculated sludge was taken from a sewage treatment plant A. 2 / O process aerobic tank activated sludge, the inoculation sludge MLSS is about 5.0g / L.

[0029] The reactor is controlled by a time switch at each stage. The initial operation cycle is 4 hours, including 5 minutes of water inlet, 205 minutes of aeration, 15 minutes of sedimentation, 5 minutes of drainage, and 10 minutes of idle time. After the reactor is running stably, the aeration time of 205 minutes is extended to 215 minutes, and the sedimentation time of 15 minutes is shortened to 5 minutes.

[0030] The drainage ratio is 60%, and the influent is artificial simulated wastewater. The specific composition is as follows: each liter of artificial simulated wastewater contains 400mg CH3COONa, 1000mg CH3CH2COONa, 248mg NH4Cl, 29.25mg KH2PO4, 37.41mg K2HPO4, 97mgMgSO4, 75mg CaCl2, 10mg EDTA and 0.05mL trace element solution. The specific composition of the trace element solution is as follows: 1.5mg / L FeCl3·6H2O, 0.15mg / L H3BO3, 0.03mg / L CuSO4·5H2O, 0.03mg / L KI, 0.12mg / LMnCl2·4H2O, 0.058mg / L ZnCl2, 0.15mg / L CoCl2·6H2O, 0.06mg / L Na2MoO4·2H2O. NH4 + -N, TN, COD concentrations are 40, 80, 1000 mg / L respectively. After 30 days of cultivation in the reactor, fully granulated aerobic granular sludge can be obtained. The obtained sludge has a round and regular shape and an average particle size of about 0.3 mm. At this time, the reactor is in an efficient operation state.

[0031] In order to investigate the changes in pollutant removal rate during the entire aeration process, water samples were taken for testing at 0 min, 20 min, 40 min, 60 min, 90 min, 120 min, 150 min, 180 min, and 215 min. The specific results are shown in Table 1.

[0032] Table 1 Changes in pollutant removal rate during aeration

[0033]

[0034]

[0035] As shown in Table 1, after 215 min of micro-nano aeration, NH4 + -N, TN, COD contents were only 0.919, 11.998, 2.513 mg / L respectively. However, when the aeration time was 150 min, we found that the removal efficiency of these three pollutants was close to saturation. Therefore, in order to improve the operation efficiency of the reactor, the operation cycle of the reactor was adjusted to 3h, including 5min of water inlet, 155min of aeration, 5min of sedimentation, 5min of drainage, 10 minutes of idleness, and a drainage ratio of 60%. The inlet concentration remained unchanged. At this time, the aerobic granular sludge still maintained a regular and rounded appearance, the average particle size increased steadily, and maintained excellent pollutant removal efficiency.

[0036] It can be seen that after shortening the aeration time by 60 minutes, the growth condition of the obtained aerobic granular sludge and the pollutant removal efficiency can still remain stable, indicating that micro-nano aeration technology has a significant promoting effect on the structural stability and functional maintenance of aerobic granular sludge, can reduce the cultivation time of aerobic granular sludge, and accelerate the formation of aerobic granular sludge.

[0037] In addition, from the perspective of energy consumption, the energy consumption of the reactor mainly comes from the power consumption of the electromagnetic air pump during the aeration stage. It is known that the power of the electromagnetic air pump is 35W, and the power consumption and carbon emissions in one operating cycle are shown in Table 1. By comparison, it is found that since the micro-nano aeration system has higher oxygen mass transfer efficiency and OH production, aerobic granular sludge formation and pollutant removal efficiency are faster, so the aeration time is shortened while ensuring the treatment efficiency. After the aeration time is shortened by 60 minutes, the single-cycle power consumption is reduced from 0.125kWh to 0.09kWh, and the corresponding carbon emissions are reduced from 0.088kg CO2 to 0.063kg CO2, achieving a 28% aeration energy saving.

[0038] Table 2 Power consumption and carbon emissions under different aeration durations

[0039]

[0040] Example 2: Aerobic granular sludge denitrification efficiency test analysis

[0041] The cultivation process of aerobic granular sludge under conventional aeration is as follows: the device adopts a cylindrical sequencing batch reactor with H / D of 10:1, an aeration device is set at the bottom of the reactor, the effective volume is 4L, and the rotor flowmeter is used to control the aeration volume of 2L / min in the oxygen flushing stage. The aeration device is a common aeration head, and the bubble particle size generated is about 2mm.

[0042] The inoculum sludge was taken from a sewage treatment plant A 2 / O process aerobic tank activated sludge, the inoculation sludge MLSS is about 5.0g / L. The drainage ratio is 60%, and the influent is artificial simulated wastewater. The specific composition is as follows: each liter of artificial simulated wastewater contains 400mgCH3COONa, 1000mg CH3CH2COONa, 248mg NH4Cl, 29.25mg KH2PO4, 37.41mg K2HPO4, 97mgMgSO4, 75mg CaCl2, 10mg EDTA and 0.05mL trace element solution. The specific composition of the trace element solution is as follows: 1.5mg / L FeCl3·6H2O, 0.15mg / L H3BO3, 0.03mg / L CuSO4·5H2O, 0.03mg / L KI, 0.12mg / LMnCl2·4H2O, 0.058mg / L ZnCl2, 0.15mg / L CoCl2·6H2O, 0.06mg / L Na2MoO4·2H2O. NH4 + -N, TN, COD concentrations were 40, 80, 1000 mg / L respectively. After 30 days of cultivation in the reactor, completely granulated aerobic granular sludge was obtained, and the obtained sludge had a round and regular shape and an average particle size of about 0.3 mm.

[0043] In order to compare the difference in nitrification rate of aerobic granular sludge cultivated under the two aeration modes, the aerobic granular sludge cultivated under the micro-nano aeration 155min cultivation mode in Example 1 was compared with the aerobic granular sludge cultivated under the conventional aeration mode. 2L of mud-water mixture was taken to ensure that the MLSS of the sludge was 5.0g / L. 0.3g NH4Cl+0.25g NaHCO3 was added to each, and aeration (normal aeration) was performed to maintain the dissolved oxygen concentration at about 2-4mg / L. Samples were taken at 0min, 20min, 40min, 60min, 90min, 120min, 150min, 180min and 240min, and NH4 + -N concentration.

[0044] Nitrification reaction refers to the process in which nitrifying bacteria convert NH4 + -N is converted to NO3 - -N process, which makes NH4 + -N was effectively removed. In order to investigate the nitrification performance of aerobic granular sludge under micro-nano aeration culture, a nitrification rate test was carried out, and the results are shown in Table 3. The data were fitted and calculated, and the specific nitrification rate (AUR) of aerobic granular sludge cultured with micro-nano aeration was 3.9293 mg N / (g VSS·h), which was 2.3 times that of the conventional aeration reactor (1.6904 mg N / (gVSS·h)).

[0045] Table 3 NH4+ -N content variation over time

[0046]

[0047] In order to compare the difference in denitrification rate of aerobic granular sludge cultured under the two aeration modes, the aerobic granular sludge under the micro-nano aeration 155min culture mode in Example 1 was compared with the aerobic granular sludge under the conventional aeration mode. 2L of mud-water mixture was taken to ensure that the MLSS of the sludge was 5.0g / L. 0.3g KNO3 was added to each, and stirred to simulate the anoxic tank environment to ensure that the dissolved oxygen was 0mg / L throughout the process. Samples were taken at 0min, 10min, 20min, 30min, 40min, 50min, 60min, 90min and 120min, and NO3 was measured. - -N concentration.

[0048] Denitrification refers to the process in which denitrifying bacteria use carbon sources in water to convert NO3 - -N is reduced to N2, thereby removing TN from sewage. In order to investigate the denitrification performance of aerobic granular sludge under micro-nano aeration culture, a denitrification rate test was carried out, and the results are shown in Table 4. The data were fitted and calculated, and the denitrification rate (NUR) of aerobic granular sludge cultured with micro-nano aeration was divided into two sections. The first section (0-20min) NUR was 25.5462mg N / (g VSS·h), which was much larger than the 20.6703mg N / (g VSS·h) of conventional aeration. During this period, denitrifying bacteria used the fast carbon source in the influent for denitrification, and the denitrification rate was fast, indicating that the influent contained carbon sources that could be quickly utilized by denitrifying bacteria. The reaction time of this section was only 20min, indicating that the total amount of fast carbon sources in the influent was limited. The NUR of the second stage (30-60min) was 2.7154mg N / (gVSS·h), which was almost twice that of the conventional aeration reactor (1.5685mg N / (g VSS·h)). During this period, denitrifying bacteria used the slow carbon source in the influent to denitrify. In summary, aerobic granular sludge cultured under micro-nano aeration mode has better denitrification performance.

[0049] Table 4NO3 - -N content variation over time

[0050]

[0051] Example 3: Comparison of basic properties of conventional bubbles and micro-nano bubbles in aerobic granular sludge system

[0052] In order to compare the performance of aerobic granular sludge cultivated under micro-nano aeration under conventional bubbles and micro-nano bubbles, the aerobic granular sludge under the micro-nano aeration 155 min cultivation mode in Example 1 and the aerobic granular sludge under the conventional aeration mode in Example 2 were taken, and 2L of mud-water mixture was taken from each to ensure that the sludge MLSS was 5.0 g / L. Ordinary aeration and micro-nano aeration were used respectively to maintain the dissolved oxygen concentration at 8-9 mg / L, and 0.25 mM of p-chlorobenzoic acid was added to each (the formation of ·OH is generally indirectly characterized by the removal of pointer compounds, such as p-chlorobenzoic acid). The cumulative amount of ·OH concentration in the water body over time was characterized by measuring the change in the content of p-chlorobenzoic acid in the mud-water mixture.

[0053] Linear regression fitting was used to calculate the oxygen transfer rate (OTR). Figure 2 As shown. The oxygen transfer coefficient (K La ) is 0.5189min -1 , K of the conventional aeration group La Only 0.2539min -1 ; The OTR of the micro-nano aeration group is 0.2373kg / m 3 / h, is the conventional aeration group (0.1135kg / m 3 The above results show that micro-nano bubbles can greatly improve the oxygen mass transfer efficiency and are expected to provide technical support for reducing aeration energy consumption.

[0054] When the micro-nano bubbles shrink and burst, the dramatic changes caused by the disappearance of the gas-liquid interface will release the energy accumulated by the high concentration of positive and negative ions on the interface, thereby generating ·OH. The strong oxidizing property of ·OH can convert difficult-to-degrade organic matter or emerging pollutants into more easily degradable biological intermediates, thereby improving the biodegradability of organic pollutants and further accelerating the degradation efficiency of pollutants. Figure 3 As shown in the figure, the exposure of ·OH produced in the two reaction systems was simulated. It was found that after 3 hours of aeration, the exposure of ·OH in the conventional aeration system was 0.68×10 -11 Ms, while the exposure amount of ·OH in the micro-nano aeration system can reach 1.75×10 -11 Ms, indicating that the micro-nano aeration system can generate more ·OH, which will be more conducive to the removal of pollutants and emerging pollutants in the reaction system.

[0055] Example 4: Comparison of pollutant removal characteristics between conventional bubbles and micro-nano bubbles in aerobic granular sludge system

[0056] In order to compare the pollutant removal characteristics of aerobic granular sludge cultured under micro-nano aeration under conventional bubbles and micro-nano bubbles, the reactor with micro-nano aeration 155 min culture mode in Example 1 and the reactor with conventional aeration in Example 2 were operated. The aerobic granular sludge was obtained under the micro-nano aeration 155 min culture mode in Example 1, and the sludge MLSS was 5.0 g / L. Other conditions were also consistent with those in Examples 1 and 2. Samples were taken at 0 day, 5 day, 10 day, 15 day, 20 day, 25 day, 30 day, 35 day, 40 day, 45 day and 50 day, and the NH4 + -N, TN and COD concentrations.

[0057] The results are as follows Figure 4 As shown in the figure, there is no significant difference in the removal effect of pollutants between the two aeration systems, and the removal efficiency of ammonia nitrogen and COD can always be stabilized at more than 95%. However, the removal effect of AGS on total nitrogen (TN) in the micro-nano aeration mode is always higher than that in the conventional aeration mode. The main reason may be that the proportion of large-particle AGS in the micro-nano aeration reactor is relatively high, the internal anoxic microenvironment is expanded, and the number of denitrifying bacteria in large-particle AGS is relatively large, which is more conducive to the denitrification of denitrifying bacteria. In addition, during the contraction and rupture of micro-nano bubbles, the ·OH produced also helps to further accelerate the degradation efficiency of pollutants, and the small molecular organic matter formed is more easily utilized by denitrifying bacteria, thereby improving the total nitrogen removal effect.

[0058] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. An aerobic granular sludge cultivation method based on micro-nano aeration technology, characterized in that: The aerobic granular sludge cultivation method specifically comprises the following steps: (1) A sequencing batch reactor is used, and an aeration device is arranged at the bottom of the reactor to control the aeration rate to be 1 to 5 L / min; the aeration device is an aeration device with a 0.2 to 0.3 μm fine aeration head, and the air bubble particle size generated is 1 to 100 μm; (2) Inoculating sludge into a sequencing batch reactor and starting to operate the reactor, wherein in one operation cycle, water is introduced for 3 to 7 minutes, aeration is performed for 200 to 205 minutes, sedimentation is performed for 10 to 20 minutes, drainage is performed for 3 to 7 minutes, and the reactor is left idle for 5 to 15 minutes; after the reactor is stably operated, the aeration time is adjusted to 210 to 215 minutes, the sedimentation time is adjusted to 5 to 7 minutes, and the drainage ratio is 55 to 65%; (3) After culturing for 25 to 35 days according to the operation cycle of step (2), the operation cycle is adjusted to: water intake for 3 to 7 minutes, aeration for 150 to 160 minutes, sedimentation for 3 to 7 minutes, drainage for 3 to 7 minutes, and drainage ratio of 55 to 65% to obtain aerobic granular sludge.

2. The aerobic granular sludge cultivation method according to claim 1, characterized in that: The sequencing batch reactor in step (1) is a cylindrical sequencing batch reactor with a height-to-diameter ratio of 8 to 10:1 and an effective volume of 4 to 8 L.

3. The aerobic granular sludge cultivation method according to claim 1, characterized in that: The aeration rate in step (1) is 1 to 3 L / min.

4. The aerobic granular sludge cultivation method according to claim 1, characterized in that: The sludge in step (2) is from sewage treatment plant A 2 / O process aerobic tank activated sludge.

5. The aerobic granular sludge cultivation method according to claim 1, characterized in that: In step (2), the MLSS of the inoculated sludge is 3 to 7 g / L.

6. The aerobic granular sludge cultivation method according to claim 1, characterized in that: NH4 in the water in step (2) + -N concentration is 30~50mg / L, TN concentration is 70~90mg / L, and COD concentration is 800~1200mg / L.

7. The aerobic granular sludge cultivation method according to claim 6, characterized in that: The composition of the influent in step (2) is as follows: 400mg / L CH3COONa, 1000mg / L CH3CH2COONa, 248mg / L NH4Cl, 29.25mg / LKH2PO4, 37.41mg / L K2HPO4, 97mg / L MgSO4, 75mg / L CaCl2, 10mg / L EDTA and 0.05mL trace element solution per liter of influent; the composition of the trace element solution is as follows: 1.5mg / L FeCl3·6H2O, 0.15mg / L H3BO3, 0.03mg / LCuSO4·5H2O, 0.03mg / L KI, 0.12mg / L MnCl2·4H2O, 0.058mg / L ZnCl2, 0.15mg / L CoCl2·6H2O, 0.06mg / L Na2MoO4·2H2O.

8. The aerobic granular sludge cultivation method according to claim 1, characterized in that: The specific periodic adjustment in step (3) is as follows: water intake for 5 minutes, aeration for 155 minutes, sedimentation for 5 minutes, and drainage for 5 minutes.

9. An aerobic granular sludge, characterized in that: The aerobic granular sludge is obtained by culturing the aerobic granular sludge according to any one of claims 1 to 7.

10. Use of the aerobic granular sludge described in claim 9 in the field of sewage treatment or environmental protection.

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