An aerobic granular sludge cultivation method based on micro-nano aeration technology
By employing micro-nano aeration technology in a sequencing batch reactor to optimize aeration and settling cycles, the problems of long cultivation time and high energy consumption of aerobic granular sludge under traditional aeration modes have been solved, achieving efficient pollutant removal and energy saving.
Patent Information
- Application Number
- CN202510215204.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-26
- Publication Date
- 2025-11-25
- Estimated Expiration
- 2045-02-26
AI Technical Summary
In traditional aeration modes, the cultivation time of aerobic granular sludge is long and the energy consumption is high, and micro-nano aeration technology has not yet been applied in sequencing batch reactors.
A sequencing batch reactor was used with an aeration device equipped with a fine aeration head of 0.2–0.3 μm to generate air bubbles of 1–100 μm. The aeration rate was controlled at 1–5 L/min, and the operating cycle was adjusted as follows: water inlet 3–7 min, aeration 150–215 min, settling 3–7 min, drainage 3–7 min, drainage ratio 55–65%, and culture time 25–35 days.
It improves oxygen mass transfer efficiency, generates hydroxyl radicals, promotes the growth of aerobic granular sludge and the removal of pollutants, saves energy, shortens cultivation time, and reduces energy consumption by 28%.
Smart Images
Figure CN119822501B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for cultivating aerobic granular sludge based on micro-nano aeration technology, belonging to the field of water treatment technology. Background Technology
[0002] In recent years, aerobic granular sludge has been widely studied and applied in engineering projects as an alternative to activated sludge processes. Compared to flocculent sludge, aerobic granular sludge, due to its dense biological structure, has a faster settling velocity and effectively reduces the land area required for wastewater treatment processes because it eliminates the need for secondary settling tanks. Currently, aerobic granular sludge processes often rely on sequencing batch reactors (SBRs) to enable operation at high biomass concentrations, improving its adaptability to high COD and toxic shocks. Furthermore, aerobic granular sludge technology can simultaneously perform nitrification and denitrification, reducing the use of recirculation pump systems in traditional nitrogen removal processes and thus lowering operating costs.
[0003] In the granulation process of flocculent sludge, aeration and oxygen mass transfer rate are two key factors regulating the performance of aerobic granular sludge process systems. However, due to the low solubility of oxygen in the aqueous phase and the poor oxygen transfer efficiency caused by the currently used traditional aeration modes, maintaining high dissolved oxygen levels in aerobic granular sludge processes requires a large amount of aeration, resulting in extremely high aeration energy consumption in wastewater treatment plants (approximately 50-70% of total energy consumption). Micro-nano aeration technology, due to the high internal pressure and stability of the generated micro-nano bubbles, allows the concentration of dissolved gases in the aqueous phase to exceed the corresponding gas saturation concentration, significantly improving gas dissolution and gas-liquid mass transfer efficiency. Compared with current traditional aeration systems that generate medium to large bubbles, the improved oxygen mass transfer under micro-nano aeration conditions may reduce the demand for aeration rate and energy consumption in activated sludge. Furthermore, 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 these properties, micro-nano bubbles have received considerable attention in environmental applications in recent years.
[0004] Currently, among existing technologies, CN 116589079 A discloses a method for cultivating aerobic granular sludge using micro / nano bubbles and its application. This method utilizes nanobubbles to provide oxygen to a continuous flow reactor to cultivate aerobic granular sludge, resulting in high dissolved oxygen utilization and stable, high-performance granular sludge. However, the reactor used is a continuous flow reactor, and the method does not explore cultivation in a sequencing batch reactor (SBR), which has more mature and widespread applications. Therefore, it is necessary to develop a method for cultivating aerobic granular sludge using micro / nano aeration specifically for SBRs. Summary of the Invention
[0005] Technical issues
[0006] In traditional aeration methods, the cultivation of aerobic granular sludge not only requires a long time period but also consumes extremely high aeration energy. Compared to conventional aeration methods, micro-nano aeration has higher oxygen mass transfer efficiency and continuously generates hydroxyl radicals, which not only promotes the growth of aerobic granular sludge and the removal of pollutants but also saves costs and improves energy efficiency. Currently, micro-nano aeration technology has not yet been applied in sequencing batch reactors.
[0007] Technical solution
[0008] This invention provides a method for cultivating aerobic granular sludge based on micro-nano aeration technology, the method specifically including the following steps:
[0009] (1) A sequencing batch reactor is adopted, and an aeration device is installed at the bottom of the reactor to control the aeration rate to 1-5 L / min; the aeration device is an aeration device with a fine aeration head of 0.2-0.3 μm, and the generated air bubble particle size is 1-100 μm.
[0010] (2) Inoculate sludge into the sequencing batch reactor and start running the reactor. In one operating cycle, the influent time is 3-7 min, the aeration time is 200-205 min, the settling time is 10-20 min, the drainage time is 3-7 min, and the idle time is 5-15 min. After the reactor is running stably, the aeration time is adjusted to 210-215 min, the settling time is adjusted to 5-7 min, and the drainage ratio is 55-65%.
[0011] (3) After cultivating for 25 to 35 days according to the operating cycle of step (2), the operating cycle is adjusted to: water inlet 3 to 7 min, aeration 150 to 160 min, settling 3 to 7 min, drainage 3 to 7 min, drainage ratio 55 to 65%, to obtain aerobic granular sludge.
[0012] Furthermore, the sequencing batch reactor mentioned 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, in step (2), the sludge is taken from wastewater treatment plant A. 2 / O process aerobic tank activated sludge.
[0015] Furthermore, in step (2), the MLSS of the inoculated sludge is 3-7 g / L.
[0016] Furthermore, in step (2), the NH4 in the influent... +-N concentration is 30-50 mg / L, TN concentration is 70-90 mg / L, and COD concentration is 800-1200 mg / L.
[0017] Specifically, the composition of the influent in step (2) can be as follows: per liter of influent, there are 400 mg / L CH3COONa, 1000 mg / L CH3CH2COONa, 248 mg / L NH4Cl, 29.25 mg / L KH2PO4, 37.41 mg / L K2HPO4, 97 mg / L MgSO4, 75 mg / L CaCl2, 10 mg / L EDTA, and 0.05 mL of trace element solution; the composition of the trace element solution is as follows: 1.5 mg / L FeCl3·6H2O, 0.15 mg / L H3BO3, 0.03 mg / L CuSO4·5H2O, 0.03 mg / L KI, 0.12 mg / L MnCl2·4H2O, 0.058 mg / L ZnCl2, 0.15 mg / L CoCl2·6H2O, and 0.06 mg / L Na2MoO4·2H2O.
[0018] Furthermore, the cycle adjustment in step (3) is specifically as follows: 5 minutes for water inlet, 155 minutes for aeration, 5 minutes for settling, and 5 minutes for drainage.
[0019] The present invention provides aerobic granular sludge obtained by the above method.
[0020] The aerobic granular sludge provided by this invention has applications in wastewater treatment or environmental protection.
[0021] Beneficial effects
[0022] Time-saving and efficient: This invention reveals that the oxygen transfer rate in a micro / nano aeration reactor is 0.2373 kg / m³. 3 / h, which is 2.1 times that of conventional aeration groups, and can produce 1.75×10 -11 The removal efficiencies of hydroxyl radicals, ammonia nitrogen, total nitrogen, and COD by Ms can be stably maintained at high levels of 98%, 85%, and 97%, respectively. While ensuring treatment efficiency, the aeration time is shortened by 60 minutes, saving 28% of aeration energy consumption per operating cycle compared to conventional aeration. Micro-nano aeration in sequencing batch reactors not only facilitates the cultivation and acclimatization of aerobic granular sludge and promotes pollutant removal, but also improves energy utilization efficiency and reduces cultivation time and costs. Attached Figure Description
[0023] Figure 1 Schematic diagram of an aerobic granular sludge treatment unit.
[0024] Figure 2 : Fit ln(C S-C) and time linear regression curve; Figure 2 a is the fitted ln(C) S -C) and the linear regression curve over time; Figure 2 b represents a comparison of oxygen transfer rates.
[0025] Figure 3 : ·OH exposure under two aeration modes.
[0026] Figure 4 The effectiveness of pollutant removal; Figure 4 a represents the removal effect of conventional aeration; Figure 4 b represents the removal effect of micro-nano aeration. Detailed Implementation
[0027] Example 1: Cultivation of Aerobic Granular Sludge
[0028] The device employs a cylindrical sequencing batch reactor with an H / D ratio of 10:1. An aeration device is installed at the bottom of the reactor, which has an effective volume of 4L. A rotor flow meter controls the aeration rate during the oxygenation stage to 2L / min. The reactor setup is shown in the attached diagram. Figure 1 As shown in the image. The aeration device is a 0.22μm fine aeration head, producing bubbles with a particle size of approximately 100μm, belonging to micro-nano bubbles. The inoculated sludge was taken from wastewater treatment plant A. 2 / O process aerobic tank activated sludge, the inoculated sludge MLSS is about 5.0 g / L.
[0029] A time-controlled switch is used to control the state of the reactor at each stage. In the initial stage, one operating cycle is 4 hours, including 5 minutes of water influent, 205 minutes of aeration, 15 minutes of settling, 5 minutes of drainage, and 10 minutes of idle time. After the reactor is running stably, the aeration time is extended from 205 minutes to 215 minutes, and the settling time is shortened from 15 minutes to 5 minutes.
[0030] The wastewater ratio is 60%, and the influent is artificially simulated wastewater with the following composition: per liter, the simulated wastewater contains 400 mg CH3COONa, 1000 mg CH3CH2COONa, 248 mg NH4Cl, 29.25 mg KH2PO4, 37.41 mg K2HPO4, 97 mg MgSO4, 75 mg CaCl2, 10 mg EDTA, and 0.05 mL of trace element solution. The trace element solution contains the following components: 1.5 mg / L FeCl3·6H2O, 0.15 mg / L H3BO3, 0.03 mg / L CuSO4·5H2O, 0.03 mg / L KI, 0.12 mg / L MnCl2·4H2O, 0.058 mg / L ZnCl2, 0.15 mg / L CoCl2·6H2O, and 0.06 mg / L Na2MoO4·2H2O. The simulated influent contains NH4Cl... + The concentrations of -N, TN, and COD were 40, 80, and 1000 mg / L, respectively. After 30 days of incubation in the reactor, fully granulated aerobic granular sludge was obtained. The resulting sludge had a round and regular shape with an average particle size of approximately 0.3 mm. At this point, the reactor was operating at high efficiency.
[0031] To investigate the changes in pollutant removal rate throughout the aeration process, water samples were taken at 0 min, 20 min, 40 min, 60 min, 90 min, 120 min, 150 min, 180 min, and 215 min for testing. The specific results are shown in Table 1.
[0032] Table 1. Changes in pollutant removal rate during aeration.
[0033]
[0034]
[0035] Table 1 shows that after 215 min of micro-nano aeration, NH4+ + The concentrations of -N, TN, and COD were only 0.919, 11.998, and 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, to improve the reactor's operating efficiency, the reactor's operating cycle was adjusted to 3 hours, including 5 min of influent, 155 min of aeration, 5 min of settling, 5 min of effluent discharge, and 10 min of idle time, with a discharge ratio of 60% and a constant influent concentration. Under these conditions, the aerobic granular sludge still maintained a regular and rounded appearance, with a stable increase in average particle size, and maintained excellent pollutant removal efficiency.
[0036] It is evident that even after shortening the aeration time by 60 minutes, the growth status and pollutant removal efficiency of the resulting aerobic granular sludge remained stable. This indicates that micro-nano aeration technology significantly promotes the structural stability and functional maintenance of aerobic granular sludge, reduces the cultivation time of aerobic granular sludge, and accelerates its formation.
[0037] Furthermore, from an energy consumption perspective, the reactor's energy consumption mainly originates from the power consumption of the electromagnetic air pump during the aeration stage. The electromagnetic air pump has a power of 35W, and the power consumption and carbon emissions within one operating cycle are shown in Table 1. Comparison reveals that, due to the higher oxygen mass transfer efficiency and ·OH generation of the micro-nano aeration system, aerobic granular sludge formation and pollutant removal efficiency are faster. Therefore, the aeration time can be shortened while maintaining treatment efficiency. After shortening the aeration time by 60 minutes, the single-cycle power consumption decreased from 0.125 kWh to 0.09 kWh, corresponding to a reduction in carbon emissions from 0.088 kg CO2 to 0.063 kg CO2, achieving approximately 28% energy savings in aeration.
[0038] Table 2. Power consumption and carbon emissions under different aeration durations
[0039]
[0040] Example 2: Analysis of the nitrogen removal efficiency of aerobic granular sludge
[0041] The cultivation process of aerobic granular sludge under conventional aeration is as follows: The device adopts a cylindrical sequencing batch reactor with an H / D ratio of 10:1. An aeration device is installed at the bottom of the reactor with an effective volume of 4L. The aeration rate during the oxygenation stage is controlled at 2L / min using a rotor flow meter. The aeration device is a common aeration head, which produces bubbles with a particle size of approximately 2mm.
[0042] The inoculated sludge was taken from a wastewater treatment plant A. 2 / O process aerobic tank activated sludge, the inoculated sludge MLSS is about 5.0 g / L. The wastewater ratio is 60%. The influent is artificially simulated wastewater with the following composition: per liter, the artificially simulated wastewater contains 400 mg CH3COONa, 1000 mg CH3CH2COONa, 248 mg NH4Cl, 29.25 mg KH2PO4, 37.41 mg K2HPO4, 97 mg MgSO4, 75 mg CaCl2, 10 mg EDTA, and 0.05 mL of trace element solution. The trace element solution contains the following components: 1.5 mg / L FeCl3·6H2O, 0.15 mg / L H3BO3, 0.03 mg / L CuSO4·5H2O, 0.03 mg / L KI, 0.12 mg / L MnCl2·4H2O, 0.058 mg / L ZnCl2, 0.15 mg / L CoCl2·6H2O, and 0.06 mg / L Na2MoO4·2H2O. The influent contains NH4Cl... + The concentrations of -N, TN, and COD were 40, 80, and 1000 mg / L, respectively. After 30 days of cultivation in the reactor, fully granulated aerobic granular sludge was obtained. The sludge had a round and regular shape with an average particle size of approximately 0.3 mm.
[0043] To compare the nitrification rate of aerobic granular sludge cultivated under two aeration modes, aerobic granular sludge from the micro-nano aeration 155min cultivation mode in Example 1 and aerobic granular sludge from the conventional aeration mode were compared. 2L of sludge-water mixture was taken from each, ensuring the MLSS of the sludge was 5.0g / L. 0.3g NH4Cl + 0.25g NaHCO3 were added to each mixture, and aeration (normal aeration) was performed to maintain a dissolved oxygen concentration of approximately 2–4 mg / L. Samples were taken at 0 min, 20 min, 40 min, 60 min, 90 min, 120 min, 150 min, 180 min, and 240 min to determine the NH4Cl concentration. + -N concentration.
[0044] Nitrification refers to the process by which nitrifying bacteria convert NH4+ into nitrogenous oxygen under aerobic conditions. + -N is converted to NO3 - The process of -N, which reduces the amount of NH4 in wastewater + -N was effectively removed. To investigate the nitrification performance of aerobic granular sludge under micro-nano aeration cultivation, a nitrification rate determination experiment was conducted, and the results are shown in Table 3. After fitting and calculating the data, the specific nitrification rate (AUR) of the aerobic granular sludge under micro-nano aeration cultivation was 3.9293 mg N / (g VSS·h), which is 2.3 times that of a conventional aeration reactor (1.6904 mg N / (g VSS·h)).
[0045] Table 3NH4+ Trend of -N content over time
[0046]
[0047] To compare the denitrification rate of aerobic granular sludge cultivated under two aeration modes, aerobic granular sludge from the micro-nano aeration 155-min cultivation mode in Example 1 and aerobic granular sludge from the conventional aeration mode were compared. 2L of sludge-water mixture was taken from each, ensuring the MLSS of the sludge was 5.0 g / L. 0.3 g of KNO3 was added to each mixture, and the mixture was stirred to simulate an anoxic environment, maintaining dissolved oxygen at 0 mg / L throughout the process. Samples were taken at 0 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 90 min, and 120 min to determine NO3 levels. - -N concentration.
[0048] Denitrification refers to the process by which denitrifying bacteria utilize carbon sources in water to convert NO3- into nitrogen dioxide under anaerobic (no molecular oxygen) conditions. - The process of reducing -N to N2 removes TN from wastewater. To investigate the denitrification performance of aerobic granular sludge under micro-nano aeration, a denitrification rate measurement experiment was conducted, and the results are shown in Table 4. Data fitting calculations showed that the specific denitrification rate (NUR) of the aerobic granular sludge under micro-nano aeration was divided into two segments. The first segment (0-20 min) had an NUR of 25.5462 mg N / (g VSS·h), significantly higher than the 20.6703 mg N / (g VSS·h) of conventional aeration. During this period, denitrifying bacteria utilized the rapid carbon source in the influent for denitrification, resulting in a relatively fast denitrification rate. This indicates that the influent contains a carbon source that can be rapidly utilized by denitrifying bacteria. The reaction time in this segment was only 20 min, suggesting that the total amount of rapid carbon source in the influent was limited. The NUR in the second stage (30-60 min) was 2.7154 mg N / (g VSS·h), almost twice that of a conventional aeration reactor (1.5685 mg N / (g VSS·h)). During this period, denitrifying bacteria utilized the slow carbon source in the influent for denitrification. In conclusion, aerobic granular sludge cultivated under micro-nano aeration mode exhibits superior nitrogen removal performance.
[0049] Table 4NO3 - Trend of -N content over time
[0050]
[0051] Example 3: Comparison of basic properties of conventional bubbles and micro / nano bubbles in an aerobic granular sludge system
[0052] To compare the performance of aerobic granular sludge cultivated under micro-nano aeration under conventional and micro-nano bubble conditions, 2 L of sludge-water mixtures were taken from both the aerobic granular sludge cultivated under the micro-nano aeration 155 min cultivation mode in Example 1 and the aerobic granular sludge cultivated under the conventional aeration mode in Example 2. The MLSS of the sludge was ensured to be 5.0 g / L. Both conventional and micro-nano aeration were used, maintaining a dissolved oxygen concentration of 8–9 mg / L. 0.25 mM of p-chlorobenzoic acid was added to each mixture (the formation of ·OH is generally indirectly characterized by the removal of index compounds, such as p-chlorobenzoic acid). The cumulative concentration of ·OH in the water over time was characterized by measuring the change in p-chlorobenzoic acid content in the sludge-water mixture.
[0053] Linear regression was used to fit the data to calculate the oxygen transfer rate (OTR), and the results are as follows: Figure 2 As shown. Oxygen transfer coefficient (K) of the micro / nano aeration group. La The value was 0.5189 min. -1 K of the conventional aeration group La Only 0.2539min -1 The OTR of the micro-nano aeration group was 0.2373 kg / m³. 3 / h, which is the standard aeration group (0.1135kg / m³). 3 The efficiency of oxygen transfer is 2.1 times that of aeration ( / h). These results indicate that micro- and nano-bubbles can significantly improve oxygen mass transfer efficiency, potentially providing technical support for reducing aeration energy consumption.
[0054] When micro- and nanobubbles contract and rupture, the drastic changes caused by the disappearance of the gas-liquid interface release the energy accumulated by the high concentration of positive and negative ions at the interface, thereby generating ·OH. The strong oxidizing properties of ·OH can transform recalcitrant organic matter or emerging pollutants into more readily degradable biological intermediates, thus improving the biodegradability of organic pollutants and further accelerating the degradation efficiency of pollutants. Figure 3 As shown, the exposure levels of ·OH were simulated in two reaction systems. It was found that after 3 hours of aeration, the ·OH exposure level in the conventional aeration system was 0.68 × 10⁻⁶. -11 Ms, while the ·OH exposure in the micro-nano aeration system can reach 1.75×10 -11 Ms indicates that the micro-nano aeration system can generate more ·OH, which will be more beneficial for the removal of pollutants and emerging pollutants within the reaction system.
[0055] Example 4: Comparison of pollutant removal characteristics between conventional bubbles and micro / nano bubbles in an aerobic granular sludge system
[0056] To compare the pollutant removal characteristics of aerobic granular sludge cultivated under micro-nano aeration under conventional bubble and micro-nano bubble conditions, the reactors in Example 1 with micro-nano aeration for 155 min and Example 2 with conventional aeration were run. The aerobic granular sludge was obtained under the micro-nano aeration for 155 min in Example 1, with a MLSS of 5.0 g / L. Other conditions were consistent with those in Examples 1 and 2. Samples were taken at 0 days, 5 days, 10 days, 15 days, 20 days, 25 days, 30 days, 35 days, 40 days, 45 days, and 50 days to determine the NH4+ content. + -N, TN and COD concentrations.
[0057] The results are as follows Figure 4 As shown, the two aeration systems did not exhibit significant differences in pollutant removal efficiency, with ammonia nitrogen and COD removal efficiencies consistently remaining above 95%. However, the AGS in the micro-nano aeration mode consistently demonstrated higher total nitrogen (TN) removal efficiency than the conventional aeration mode. This is likely due to the higher proportion of large-diameter AGS in the micro-nano aeration reactor, resulting in a more extensive anoxic microenvironment and a greater number of denitrifying bacteria within the large-diameter AGS, thus facilitating their nitrogen removal activity. Furthermore, the ·OH generated during the contraction and rupture of micro-nano bubbles further accelerates pollutant degradation, and the resulting small-molecule organic matter is more readily utilized by denitrifying bacteria, thereby enhancing total nitrogen removal efficiency.
[0058] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.
Claims
1. A method for cultivating aerobic granular sludge based on micro-nano aeration technology, characterized in that, The aerobic granular sludge cultivation method specifically includes the following steps: (1) A sequencing batch reactor is adopted, and an aeration device is installed at the bottom of the reactor to control the aeration rate to 1-5 L / min; the aeration device is an aeration device with a fine aeration head of 0.2-0.3 μm, and the generated air bubble particle size is 1-100 μm. (2) Inoculate sludge into the sequencing batch reactor and start running the reactor. In one operating cycle, the influent time is 3-7 min, the aeration time is 200-205 min, the settling time is 10-20 min, the drainage time is 3-7 min, and the idle time is 5-15 min. After the reactor is running stably, the aeration time is adjusted to 210-215 min, the settling time is adjusted to 5-7 min, and the drainage ratio is 55-65%. (3) After cultivating for 25 to 35 days according to the operating cycle of step (2), the operating cycle is adjusted to: water inlet 3 to 7 min, aeration 150 to 160 min, settling 3 to 7 min, drainage 3 to 7 min, drainage ratio 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 mentioned 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 method for cultivating aerobic granular sludge according to claim 1, characterized in that, In step (1), the aeration rate is 1-3 L / min.
4. The method for cultivating aerobic granular sludge according to claim 1, characterized in that, In step (2), the sludge is from wastewater treatment plant A. 2 / O process aerobic tank activated sludge.
5. The method for cultivating aerobic granular sludge according to claim 1, characterized in that, In step (2), the MLSS of the inoculated sludge is 3-7 g / L.
6. The method for cultivating aerobic granular sludge according to claim 1, characterized in that, In step (2), NH4 in the influent + -N concentration is 30-50 mg / L, TN concentration is 70-90 mg / L, and COD concentration is 800-1200 mg / L.
7. The method for cultivating aerobic granular sludge according to claim 6, characterized in that, The composition of the influent in step (2) is as follows: per liter of influent, there are 400 mg / L CH3COONa, 1000 mg / L CH3CH2COONa, 248 mg / L NH4Cl, 29.25 mg / L KH2PO4, 37.41 mg / L K2HPO4, 97 mg / L MgSO4, 75 mg / L CaCl2, 10 mg / L EDTA, and 0.05 mL of trace element solution; the composition of the trace element solution is as follows: 1.5 mg / L FeCl3·6H2O, 0.15 mg / L H3BO3, 0.03 mg / L CuSO4·5H2O, 0.03 mg / L KI, 0.12 mg / L MnCl2·4H2O, 0.058 mg / L ZnCl2, 0.15 mg / L CoCl2·6H2O, and 0.06 mg / L Na2MoO4·2H2O.
8. The method for cultivating aerobic granular sludge according to claim 1, characterized in that, In step (3), the cycle adjustment is specifically as follows: 5 minutes for water inlet, 15 minutes for aeration, 5 minutes for settling, and 5 minutes for drainage.
9. An aerobic granular sludge, characterized in that, The aerobic granular sludge is obtained by the aerobic granular sludge cultivation method according to any one of claims 1 to 7.
10. The application of the aerobic granular sludge as described in claim 9 in the fields of wastewater treatment or environmental protection.