A rapid cultivation method for aerobic granular sludge

Abstract

The present invention relates to the technical field of sewage treatment, and in particular to a method for rapid cultivation of aerobic granular sludge, comprising the following steps: S1: dehydrating the excess sludge from a municipal sewage treatment plant; S2: adding activated carbon and stirring to form a mixture A; S3: adding a pre-prepared nutrient solution to the mixture A; S4: inducing sludge granulation to gradually form a granular structure; S5: regularly adding a calcium-containing nutrient solution to the preliminary granular structure. 2+ and Mg 2+ solution; S6: adjusting the hydraulic retention time in the reactor to form a mixture of granular sludge and suspended sludge; S7: collecting granular sludge that meets the particle size requirements; S8: dehydrating and drying the collected granular sludge; the present invention simplifies the operating steps, shortens the granulation time, and enhances the stability of the sludge particles by optimizing the sludge granulation process and accurately controlling various parameters, thereby improving the overall efficiency of sewage treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a method for rapid cultivation of aerobic granular sludge. Background Art

[0002] In the field of sewage treatment, aerobic granular sludge has become one of the important technologies in wastewater treatment due to its excellent sedimentation performance, high sludge load and strong biological activity. Compared with the traditional activated sludge method, the aerobic granular sludge method can significantly improve the treatment efficiency of the system through the formation of granular sludge, reduce problems such as sludge swelling and poor sedimentation performance.

[0003] However, in practical applications, the efficient and rapid cultivation of high-quality aerobic granular sludge still faces many challenges. This is especially true when treating high-concentration organic wastewater and municipal sewage, where granular sludge takes a long time to form and is unstable, impacting treatment effectiveness. Therefore, efficient granular cultivation of sludge, particularly maintaining granular sludge stability under varying environmental conditions, remains a pressing technical challenge. Summary of the Invention

[0004] Based on the above objectives, the present invention provides a method for rapid cultivation of aerobic granular sludge.

[0005] A method for rapid cultivation of aerobic granular sludge comprises the following steps:

[0006] S1: Dewatering of excess sludge from municipal wastewater treatment plants to remove impurities and excess water;

[0007] S2: Add the sludge treated in S1 into the reactor and add activated carbon for stirring to form mixture A;

[0008] S3: Add the pre-prepared nutrient solution to the mixture A, adjust the pH value of the reactor, mix well and prepare to enter the granulation induction stage;

[0009] S4: Control the dissolved oxygen content in the reactor and perform intermittent stirring to induce sludge granulation so that the sludge gradually forms a granular structure;

[0010] S5: Regular addition of Ca-containing 2+ and Mg 2+ The solution is stirred continuously to enhance the aggregation of microorganisms and the stability of particle structure;

[0011] S6: adjusting the hydraulic retention time in the reactor and controlling the sludge concentration to maintain predetermined reaction conditions for aerobic cultivation to form a mixture of granular sludge and suspended sludge;

[0012] S7: Use a screening device to separate the granular sludge from the suspended sludge and collect the granular sludge that meets the particle size requirements;

[0013] S8: The collected granular sludge is dehydrated and dried to obtain the final aerobic granular sludge product.

[0014] Optionally, the S1 specifically includes:

[0015] S11: The residual sludge from the municipal sewage treatment plant is initially dehydrated through a mechanical filter press to reduce the sludge moisture content to 60%-70%;

[0016] S12: The sludge after preliminary dehydration is placed in a screening device to remove impurities and non-organic matter with a particle size greater than 5 mm;

[0017] S13: performing secondary centrifugal dehydration on the screened sludge to reduce the sludge moisture content to 40%-50%;

[0018] S14: The sludge is dried at low temperature by a hot air drying device to reduce the moisture content of the sludge to 20%-30%.

[0019] Optionally, the S2 specifically includes:

[0020] S21: The sludge treated in S1 is evenly added to the reactor through a conveying device, and the amount of sludge added is controlled so that it occupies 40%-60% of the reactor volume;

[0021] S22: Add activated carbon into the reactor at 1%-3% of the sludge mass;

[0022] S23: Start the stirring device in the reactor, set the stirring speed to 50-100 rpm, and stir for 20-30 minutes until the sludge and activated carbon are completely mixed to form a mixture A.

[0023] Optionally, the pre-prepared nutrient solution includes a nitrogen source, a phosphorus source and trace elements, wherein the nitrogen source is ammonium nitrate, the phosphorus source is potassium dihydrogen phosphate, and the trace elements are selected from zinc sulfate, magnesium sulfate or sodium chloride. It is specifically prepared according to a mass ratio of nitrogen to phosphorus of 10:1. The trace elements are added to the nutrient solution at 0.1%-0.5% of the total liquid volume, and the temperature of the prepared nutrient solution is controlled at 20℃-30℃.

[0024] Optionally, the S3 specifically includes:

[0025] S31: adding a pre-prepared nutrient solution to mixture A at a rate of 5% to 10% of the mixture's mass;

[0026] S32: Start the stirring device in the reactor, control the stirring speed at 60-80 rpm, and stir for 15-20 minutes;

[0027] S33: Use an acid-base regulator to adjust the pH value in the reactor to 6.5-8.0, and then enter the granulation induction stage.

[0028] Optionally, the S4 specifically includes:

[0029] S41: controlling the dissolved oxygen concentration in the reactor by a dissolved oxygen monitoring device and controlling the concentration range to be 4-8 mg / L;

[0030] S42: Start the stirring device in the reactor and operate it in an intermittent stirring mode with a stirring time of 30-40 minutes each time and stirring once every 1-2 hours, maintaining the stirring speed at 50-100 rpm until the sludge forms a stable particle structure.

[0031] Optionally, the S5 specifically includes:

[0032] S51: Add Ca to the initial particle structure in the reactor every 24-48 hours 2+ and Mg 2+ A mixed solution containing Ca 2+ With Mg 2+ The mass ratio of Ca is 2:1, 2+ The concentration is 50-100 mg / L, Mg 2+ The concentration is 25-50 mg / L, and the addition amount is 5%-10% of the total liquid volume of the reactor;

[0033] S52: Each time Ca is added 2+ and Mg 2+ After the solution is mixed, start the stirring device for uniform stirring. The stirring speed is maintained at 50-80 rpm and the stirring time is 30 minutes to ensure that the solution is evenly distributed.

[0034] Optionally, the S6 specifically includes:

[0035] S61: By adjusting the inlet flow rate and the outlet flow rate, the hydraulic retention time in the reactor is controlled to be 4.5-5.5 hours, and the inlet flow rate is 0.5-1.0m 3 / h, drainage flow rate is 0.3-0.8m 3 / h;

[0036] S62: Use a sludge concentration detection device to monitor the sludge concentration in the reactor in real time and control the sludge concentration to 6-8 g / L. When the concentration exceeds 8 g / L, about 5% of the sludge is discharged every 12 hours through the sludge discharge system. When the concentration is lower than 6 g / L, the sludge content is increased to the target range through the water inlet system.

[0037] S63: After the hydraulic retention time and sludge concentration reach the set standards, continue aerobic cultivation, and the aeration volume of the aeration system is controlled at 1.5-2.5L / min to maintain the mixed state of granular sludge and suspended sludge.

[0038] Optionally, the S7 specifically includes:

[0039] S71: Start the screening device to separate the granular sludge from the suspended sludge. The sieve size of the screening device is set to 1-2 mm.

[0040] S72: The sludge is evenly passed through the screen by the vibration mode of the screening device. Each screening lasts for 10-15 minutes.

[0041] S73: Collect the granular sludge that passes through the screen and store it in a prepared container for later use.

[0042] Optionally, the S8 specifically includes:

[0043] S81: placing the collected granular sludge into a centrifugal dehydration device, setting the speed to 1500-2000 rpm, and continuing the dehydration time for 15-30 minutes until the sludge moisture content drops to 20%-30%;

[0044] S82: The dehydrated granular sludge is transferred to a drying device, the drying temperature is controlled at 60°C-80°C, and the drying time is 2-4 hours, until the sludge moisture content is reduced to 5%-10%;

[0045] S83: Cooling the dried granular sludge to room temperature and sealing it with a packaging device to obtain a final aerobic granular sludge product.

[0046] Beneficial effects of the present invention:

[0047] The present invention optimizes the sludge granulation culture process, combines the scientific ratio of nutrient solution, precise control of dissolved oxygen and Ca 2 The regular addition of Ca + and Mg2+ realizes the rapid induction and enhancement of sludge granulation. Compared with the existing technology, the present invention simplifies the operation steps during the cultivation process, and through reasonable parameter control, significantly shortens the sludge granulation time and improves the sludge particle stability, making it more suitable for the treatment of high-concentration organic wastewater.

[0048] The present invention adopts a staged sludge treatment scheme, effectively controls each link of sludge dehydration, stirring, granulation, screening and dehydration and drying, ensures the connection and consistency between each step, and makes the cultivated granular sludge have excellent particle size distribution and strong mechanical stability, solves the problem of instability of granular sludge in the prior art, and improves the overall efficiency of the sewage treatment system. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0050] Figure 1 Schematic diagram of a rapid aerobic granular sludge cultivation method according to an embodiment of the present invention;

[0051] Figure 2 Schematic diagram of the process of aerobic cultivation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. It is also noted that, to provide a more detailed description, the following embodiments are best and preferred embodiments, and those skilled in the art may employ alternative methods for implementing certain known technologies. Furthermore, the accompanying drawings are intended only to provide a more detailed description of the embodiments and are not intended to limit the present invention.

[0053] It should be noted that references in the specification to "one embodiment," "an embodiment," "an exemplary embodiment," "some embodiments," etc. indicate that the described embodiments may include specific features, structures, or characteristics, but not every embodiment necessarily includes such specific features, structures, or characteristics. In addition, when specific features, structures, or characteristics are described in conjunction with an embodiment, it is within the knowledge of persons skilled in the relevant art to implement such features, structures, or characteristics in conjunction with other embodiments (whether or not explicitly described).

[0054] In general, terms can be understood, at least in part, from their use in context. For example, depending at least in part on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in the singular sense, or can be used to describe a combination of features, structures, or characteristics in the plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey an exclusive set of factors, but can instead, depending at least in part on the context, allow for the presence of other factors that are not necessarily explicitly described.

[0055] Example 1

[0056] like Figure 1-Figure 2 As shown, a method for rapid cultivation of aerobic granular sludge comprises the following steps:

[0057] S1: Dewater the excess sludge from municipal sewage treatment plants and remove impurities and excess water to make the sludge suitable for subsequent treatment;

[0058] S2: The sludge treated in S1 is added to the reactor and activated carbon is added and stirred to form mixture A. After stirring evenly, it enters the nutrient addition stage;

[0059] S3: Add the pre-prepared nutrient solution to the mixture A, adjust the pH value of the reactor, mix well and prepare to enter the granulation induction stage;

[0060] S4: Control the dissolved oxygen content in the reactor and perform intermittent stirring to induce sludge granulation so that the sludge gradually forms a granular structure;

[0061] S5: Regular addition of Ca-containing 2+ and Mg 2+ The solution is stirred continuously to enhance the aggregation of microorganisms and the stability of particle structure, ensuring that the aerobic culture stage begins after the granulation is completed;

[0062] S6: adjusting the hydraulic retention time in the reactor and controlling the sludge concentration to maintain predetermined reaction conditions for aerobic cultivation to form a mixture of granular sludge and suspended sludge;

[0063] S7: Use a screening device to separate the granular sludge from the suspended sludge and collect the granular sludge that meets the particle size requirements;

[0064] S8: The collected granular sludge is dehydrated and dried to obtain the final aerobic granular sludge product.

[0065] S1 specifically includes:

[0066] S11: The residual sludge from the municipal sewage treatment plant is initially dehydrated by a mechanical filter press to reduce the sludge moisture content to 65%;

[0067] S12: The sludge after preliminary dehydration is placed in a screening device to remove impurities and non-organic matter with a particle size greater than 5 mm;

[0068] S13: performing secondary centrifugal dehydration on the screened sludge to reduce the sludge moisture content to 45%;

[0069] S14: The sludge is dried at low temperature by a hot air drying device to reduce the moisture content of the sludge to 25% to ensure that it is suitable for subsequent treatment.

[0070] S2 specifically includes:

[0071] S21: The sludge treated in S1 is evenly added to the reactor through the conveying equipment, and the amount of sludge added is controlled so that it occupies 50% of the reactor volume;

[0072] S22: Add activated carbon to the reactor at 2% of the sludge mass to ensure that the initial ratio of activated carbon to sludge meets the predetermined requirements;

[0073] S23: Start the stirring device in the reactor, set the stirring speed to 85 rpm, and stir for 25 minutes until the sludge and activated carbon are completely mixed to form a mixture A. After completion, enter the next stage.

[0074] The pre-prepared nutrient solution includes a nitrogen source, a phosphorus source and trace elements, wherein the nitrogen source is ammonium nitrate, the phosphorus source is potassium dihydrogen phosphate, and the trace elements are selected from zinc sulfate. The nutrient solution is prepared according to a mass ratio of nitrogen to phosphorus of 10:1. The trace elements are added to the nutrient solution at 0.3% of the total liquid volume. The temperature of the prepared nutrient solution is controlled at 25°C.

[0075] S3 specifically includes:

[0076] S31: adding a pre-prepared nutrient solution to mixture A at 7% of the mass of the mixture;

[0077] S32: Start the stirring device in the reactor, control the stirring speed at 70 rpm, and stir for 18 minutes to fully mix the nutrient solution and mixture A;

[0078] S33: Use an acid-base regulator to adjust the pH value in the reactor to 7.0, and then enter the granulation induction stage.

[0079] S4 specifically includes:

[0080] S41: The dissolved oxygen concentration in the reactor is controlled by a dissolved oxygen monitoring device and the concentration range is controlled within 6 mg / L. The aeration volume is continuously monitored and adjusted to ensure that the dissolved oxygen concentration is maintained within the set range.

[0081] S42: Start the stirring device in the reactor and operate it in an intermittent stirring mode with a stirring time of 35 minutes each time and stirring once every 1.5 hours, maintaining the stirring speed at 70 rpm until the sludge forms a stable particle structure.

[0082] S5 specifically includes:

[0083] S51: Add Ca to the preliminary particle structure in the reactor every 36 hours 2+ and Mg 2+The mixed solution contains Ca 2+ With Mg 2+ The mass ratio of Ca is 2:1, 2+ The concentration is 75mg / L, Mg 2+ The concentration is 37.5 mg / L, and the amount added is 8% of the total liquid volume of the reactor;

[0084] S52: Each time Ca is added 2+ and Mg 2+ After the solution is mixed, start the stirring device for uniform stirring, maintain the stirring speed at 70 rpm, and stir for 30 minutes to ensure that the solution is evenly distributed.

[0085] S6 specifically includes:

[0086] S61: By adjusting the inlet flow rate and the outlet flow rate, the hydraulic retention time in the reactor is controlled to be 5 hours and the inlet flow rate is 0.7m 3 / h, drainage flow rate is 0.5m 3 / h, ensuring that the hydraulic retention time is within the target range;

[0087] S62: Use a sludge concentration detection device to monitor the sludge concentration in the reactor in real time and control the sludge concentration to 7 g / L. When the concentration exceeds 8 g / L, about 5% of the sludge is discharged every 12 hours through the sludge discharge system. When the concentration is lower than 6 g / L, the sludge content is increased to the target range through the water inlet system.

[0088] S63: After the hydraulic retention time and sludge concentration reach the set standards, continue aerobic cultivation. The aeration volume of the aeration system is controlled at 2L / min to ensure a stable oxygen supply and maintain a mixed state of granular sludge and suspended sludge.

[0089] S7 specifically includes:

[0090] S71: Start the screening device to separate the granular sludge from the suspended sludge. The sieve size of the screening device is set to 1.5 mm to ensure that the granular sludge within the particle size range passes through the screening;

[0091] S72: The sludge is evenly passed through the screen by the vibration mode of the screening device. Each screening lasts for 12 minutes to ensure that the sludge fully contacts the screen surface for effective separation.

[0092] S73: The granular sludge that passes through the screen is collected and stored in a prepared container for later use, and the suspended sludge remaining after screening is transferred to a recovery system for further processing.

[0093] S8 specifically includes:

[0094] S81: placing the collected granular sludge into a centrifugal dehydration device, setting the speed to 1800 rpm, and continuing the dehydration for 20 minutes until the sludge moisture content drops to 25%;

[0095] S82: The dehydrated granular sludge is transferred to a drying device, the drying temperature is controlled at 70°C, and the drying time is 3 hours, until the sludge moisture content is reduced to 8%;

[0096] S83: Cooling the dried granular sludge to room temperature and sealing it with a packaging device to obtain a final aerobic granular sludge product.

[0097] Example 2

[0098] S1: The residual sludge from the municipal sewage treatment plant is dehydrated through a mechanical filter press to reduce the sludge moisture content to 60%. The dehydrated sludge is then screened to remove impurities and non-organic matter with a particle size greater than 5 mm. The screened sludge is then subjected to a secondary centrifugal dehydration treatment to reduce the moisture content to 40%. Finally, the sludge is low-temperature dried through a hot air drying device to reduce the moisture content to 20%.

[0099] S2: The treated sludge is uniformly added to the reactor through a conveying device, and the added sludge accounts for 40% of the reactor volume; activated carbon is added according to 1% of the sludge mass, and the stirring device is started at a stirring speed of 50 rpm for 20 minutes until the sludge and activated carbon are fully mixed to form a mixture A;

[0100] S3: Add 5% of the mass of a pre-formulated nutrient solution to mixture A. The nutrient solution is prepared by mixing ammonium nitrate and potassium dihydrogen phosphate in a mass ratio of 10:1 and contains 0.1% magnesium sulfate as a trace element. The temperature of the nutrient solution is controlled at 20°C. Start the stirring device at a stirring speed of 60 rpm for 15 minutes. Then, adjust the pH value in the reactor to 6.5 using an acid-base regulator.

[0101] S4: The dissolved oxygen concentration in the reactor is controlled at 4 mg / L by a dissolved oxygen monitoring device; intermittent stirring is started, with a stirring time of 30 minutes each time and a stirring interval of 1 hour, and the stirring speed is set to 50 rpm until a stable particle structure is formed;

[0102] S5: Add Ca to the granular structure every 24 hours 2+ With Mg 2+ The mixed solution contains Ca 2+ With Mg 2+ The mass ratio is 2:1, of which Ca 2+ The concentration is 50mg / L, Mg 2+The concentration was 25 mg / L, and the amount added was 5% of the total liquid volume of the reactor; the stirring speed was maintained at 50 rpm, and the stirring time was 30 minutes;

[0103] S6: By adjusting the water inlet and drainage systems, the hydraulic retention time is controlled to 4.5 hours and the water inlet flow rate is 0.5m 3 / h, drainage flow rate is 0.3m 3 / h; the sludge concentration is controlled at 6g / L through the sludge concentration detection device; after the hydraulic retention time and sludge concentration reach the set standard, the aeration volume is controlled at 1.5L / min to ensure a stable oxygen supply and continue aerobic cultivation;

[0104] S7: Start the screening device with a sieve size of 1 mm and a screening time of 10 minutes to separate the granular sludge, collect it and store it in a prepared container for later use;

[0105] S8: Place the granular sludge in a centrifugal dehydration device, set the speed to 1500 rpm, and dehydrate for 15 minutes until the sludge moisture content drops to 20%; then transfer the dehydrated granular sludge to a drying device, control the drying temperature at 60°C, and dry for 2 hours until the moisture content drops to 5%. After cooling to room temperature, seal and package.

[0106] Example 3

[0107] S1: The residual sludge from the municipal sewage treatment plant is dehydrated through a mechanical filter press to reduce the sludge moisture content to 70%. The dehydrated sludge is then screened to remove impurities with a particle size greater than 5mm and non-organic matter. The screened sludge is then subjected to a secondary centrifugal dehydration treatment to reduce the moisture content to 50%. Finally, the sludge is low-temperature dried through a hot air drying device to reduce the moisture content to 30%.

[0108] S2: The treated sludge is uniformly added to the reactor through a conveying device, and the added sludge accounts for 60% of the reactor volume; activated carbon is added according to 3% of the sludge mass, and the stirring device is started at a stirring speed of 100 rpm for 30 minutes until the sludge and activated carbon are fully mixed to form a mixture A;

[0109] S3: Add 10% of the mass of a pre-formulated nutrient solution to mixture A. The nutrient solution is prepared by mixing ammonium nitrate and potassium dihydrogen phosphate in a mass ratio of 10:1 and contains 0.5% sodium chloride as a trace element. The temperature of the nutrient solution is controlled at 30°C. Start the stirring device at a stirring speed of 80 rpm for 20 minutes. Then, adjust the pH value in the reactor to 8.0 using an acid-base regulator.

[0110] S4: The dissolved oxygen concentration in the reactor is controlled at 8 mg / L by a dissolved oxygen monitoring device; intermittent stirring is started, with a stirring time of 40 minutes each time and a stirring time of 2 hours, and the stirring speed is set to 100 rpm until a stable particle structure is formed;

[0111] S5: Add Ca to the granular structure every 48 hours 2+ With Mg 2+ The mixed solution contains Ca 2+ With Mg 2+ The mass ratio is 2:1, of which Ca 2+ The concentration is 100mg / L, Mg 2+ The concentration is 50 mg / L, and the amount added is 10% of the total liquid volume of the reactor; the stirring speed is maintained at 80 rpm, and the stirring time is 30 minutes;

[0112] S6: By adjusting the water inlet and drainage systems, the hydraulic retention time is controlled to 5.5 hours and the water inlet flow rate is 1.0m 3 / h, drainage flow rate is 0.8m 3 / h; the sludge concentration is controlled at 8g / L through the sludge concentration detection device; after the hydraulic retention time and sludge concentration reach the set standard, the aeration volume is controlled at 2.5L / min to ensure a stable oxygen supply and continue aerobic cultivation;

[0113] S7: Start the screening device with a sieve size of 2 mm and a screening time of 15 minutes to separate the granular sludge, collect it and store it in a prepared container for later use;

[0114] S8: Place the granular sludge into a centrifugal dehydration device, set the speed to 2000 rpm, and dehydrate for 30 minutes until the sludge moisture content drops to 30%; then transfer the dehydrated granular sludge to a drying device, control the drying temperature at 80°C, and dry for 4 hours until the moisture content drops to 10%. After cooling to room temperature, seal and package.

[0115] Table 1 Comparison of performance data of aerobic granular sludge products

[0116] Comparison items Example 1 Example 2 Example 3 Sludge moisture content (%) 8 5 10 Sludge particle size (mm) 1.5 1 2 Redox potential (mV) 300 270 280 Particle strength (N) 50 45 48 Organic matter degradation rate (%) 95 92 93 Oxygen consumption rate (mg / L / h) 5.5 5.2 5.3 <![CDATA[Specific surface area of sludge (m 2 / g)]]> 55 52 53

[0117] It can be seen from Table 1 above that although the sludge moisture content (8%) and particle size (1.5 mm) of Example 1 are not the lowest or smallest, it still performs moderately in these two indicators and is suitable for the needs of sludge treatment; the redox potential of Example 1 reaches 300 mV, which is significantly higher than that of the other two examples, showing better redox ability, which is very beneficial to the biodegradation process of sludge; the particle strength of Example 1 reaches 50 N, indicating that its particle structure is more solid and stable, and is less likely to break during treatment and use than Examples 2 and 3; the organic matter degradation rate of Example 1 reaches 95%, which is the highest among the three examples, indicating that it is more efficient in removing organic matter from sludge and has the best treatment effect; the oxygen consumption rate of Example 1 is 5.5 mg / L / h, indicating that it has high biological activity and high oxygen utilization rate during aerobic treatment; the sludge specific surface area of ​​Example 1 is 55 m 2 / g, indicating that it has a larger surface contact area, which is conducive to the attachment and reaction of microorganisms. Based on the above data, Example 1 performs well in multiple key indicators such as redox potential, particle strength, and organic matter degradation rate, and is the best implementation scheme.

[0118] Table 2 Comparison of other performance data

[0119]

[0120]

[0121] As can be seen from Table 2 above, the particle settling velocity of Example 1 is 1.8 cm / min, indicating that the particles settle quickly, which is conducive to the rapid separation and collection of sludge; the residence time of Example 1 is 5 hours, which maintains a relatively ideal reaction time and ensures sufficient aerobic treatment effect; the granular sludge density of Example 1 is 1.2 g / cm 3 , the density is larger, the granular sludge is more compact, which is conducive to improving the stability of the sludge; the biological activity of Example 1 reaches 150mgCOD / gVSS, showing high microbial activity, which is conducive to the effective degradation of organic matter in the sludge; the ammonia nitrogen removal rate of Example 1 is 85%, which is higher than that of other examples, indicating that it has a better effect in nitrogen removal; the phosphorus removal rate of Example 1 is 90%, which is also the highest among the three examples, indicating that it performs well in phosphorus removal; the operating cost of Example 1 is 35 yuan / m 3 , which is in a relatively economical range and has relatively low costs. From the above data, it can be seen that Example 1 shows the best results in terms of particle settling rate, sludge density, biological activity, ammonia nitrogen and phosphorus removal rates, and has a low operating cost, making it the best implementation scheme overall.

[0122] The present invention encompasses any alternatives, modifications, equivalents, and solutions that fall within the spirit and scope of the present invention. To provide a thorough understanding of the present invention, specific details are described in detail below in connection with the preferred embodiments of the present invention, but those skilled in the art will be able to fully understand the present invention without these detailed descriptions. Furthermore, to avoid unnecessary confusion regarding the essence of the present invention, well-known methods, processes, procedures, components, and circuits have not been described in detail.

[0123] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for rapid cultivation of aerobic granular sludge, characterized in that: The following steps are involved: S1: Dewatering of excess sludge from municipal wastewater treatment plants to remove impurities and excess water; S2: Add the sludge treated in S1 into the reactor and add activated carbon for stirring to form mixture A; S3: Add the pre-prepared nutrient solution to the mixture A, adjust the pH value of the reactor, mix well and prepare to enter the granulation induction stage; S4: Control the dissolved oxygen content in the reactor and perform intermittent stirring to induce sludge granulation so that the sludge gradually forms a granular structure; S5: Regular addition of Ca-containing 2+ and Mg 2+ The solution is stirred continuously to enhance the aggregation of microorganisms and the stability of particle structure; S6: adjusting the hydraulic retention time in the reactor and controlling the sludge concentration to maintain predetermined reaction conditions for aerobic cultivation to form a mixture of granular sludge and suspended sludge; S7: Use a screening device to separate the granular sludge from the suspended sludge and collect the granular sludge that meets the particle size requirements; S8: Dehydrating and drying the collected granular sludge to obtain a final aerobic granular sludge product; Said S1 specifically includes: S11: The residual sludge from the municipal sewage treatment plant is initially dehydrated through a mechanical filter press to reduce the sludge moisture content to 60%-70%; S12: The sludge after preliminary dehydration is placed in a screening device to remove impurities and non-organic matter with a particle size greater than 5 mm; S13: performing secondary centrifugal dehydration on the screened sludge to reduce the sludge moisture content to 40%-50%; S14: The sludge is dried at low temperature by a hot air drying device to reduce the moisture content of the sludge to 20%-30%; The S6 specifically includes: S61: By adjusting the inlet flow rate and the outlet flow rate, the hydraulic retention time in the reactor is controlled to be 4.5-5.5 hours, and the inlet flow rate is 0.5-1.0m 3 / h, drainage flow rate is 0.3-0.8m 3 / h; S62: Use a sludge concentration detection device to monitor the sludge concentration in the reactor in real time and control the sludge concentration to 6-8 g / L. When the concentration exceeds 8 g / L, 5% of the sludge is discharged every 12 hours through the sludge discharge system. When the concentration is lower than 6 g / L, the sludge content is increased to the target range through the water inlet system. S63: After the hydraulic retention time and sludge concentration reach the set standards, continue aerobic cultivation, and the aeration volume of the aeration system is controlled at 1.5-2.5L / min to maintain the mixed state of granular sludge and suspended sludge.

2. The method for rapid cultivation of aerobic granular sludge according to claim 1, characterized in that: The S2 specifically includes: S21: The sludge treated in S1 is evenly added to the reactor through a conveying device, and the amount of sludge added is controlled so that it occupies 40%-60% of the reactor volume; S22: Add activated carbon into the reactor at 1%-3% of the sludge mass; S23: Start the stirring device in the reactor, set the stirring speed to 50-100 rpm, and stir for 20-30 minutes until the sludge and activated carbon are completely mixed to form a mixture A.

3. The method for rapid cultivation of aerobic granular sludge according to claim 1, characterized in that: The pre-formulated nutrient solution includes a nitrogen source, a phosphorus source and trace elements, wherein the nitrogen source is ammonium nitrate, the phosphorus source is potassium dihydrogen phosphate, and the trace elements are selected from zinc sulfate, magnesium sulfate or sodium chloride. The nutrient solution is prepared according to a mass ratio of nitrogen to phosphorus of 10:

1. The trace elements are added to the nutrient solution at a ratio of 0.1% to 0.5% of the total liquid volume. The temperature of the prepared nutrient solution is controlled at 20°C to 30°C.

4. The method for rapid cultivation of aerobic granular sludge according to claim 1, characterized in that: The S3 specifically includes: S31: adding a pre-formulated nutrient solution to mixture A at a rate of 5% to 10% by mass of the mixture; S32: Start the stirring device in the reactor, control the stirring speed at 60-80 rpm, and stir for 15-20 minutes; S33: Use an acid-base regulator to adjust the pH value in the reactor to 6.5-8.0, and then enter the granulation induction stage.

5. The method for rapid cultivation of aerobic granular sludge according to claim 1, characterized in that: The S4 specifically includes: S41: controlling the dissolved oxygen concentration in the reactor by a dissolved oxygen monitoring device and controlling the concentration range to be 4-8 mg / L; S42: Start the stirring device in the reactor and operate it in an intermittent stirring mode with a stirring time of 30-40 minutes each time and stirring once every 1-2 hours, maintaining the stirring speed at 50-100 rpm until the sludge forms a stable particle structure.

6. The method for rapid cultivation of aerobic granular sludge according to claim 1, characterized in that: The S5 specifically includes: S51: Add Ca to the initial particle structure in the reactor every 24-48 hours 2+ and Mg 2+ A mixed solution containing Ca 2+ With Mg 2+ The mass ratio of Ca is 2:1, 2+ The concentration is 50-100 mg / L, Mg 2+ The concentration is 25-50 mg / L, and the addition amount is 5%-10% of the total liquid volume of the reactor; S52: Each time Ca is added 2+ and Mg 2+ After the solution is mixed, start the stirring device for uniform stirring. The stirring speed is maintained at 50-80 rpm and the stirring time is 30 minutes to ensure that the solution is evenly distributed.

7. The method for rapid cultivation of aerobic granular sludge according to claim 1, characterized in that: The S7 specifically includes: S71: Start the screening device to separate the granular sludge from the suspended sludge. The sieve size of the screening device is set to 1-2 mm. S72: The sludge is evenly passed through the screen by the vibration mode of the screening device. Each screening lasts for 10-15 minutes. S73: Collect the granular sludge that passes through the screen and store it in a prepared container for later use.

8. The method for rapid cultivation of aerobic granular sludge according to claim 1, characterized in that: The S8 specifically includes: S81: placing the collected granular sludge into a centrifugal dehydration device, setting the speed to 1500-2000 rpm, and continuing the dehydration time for 15-30 minutes until the sludge moisture content drops to 20%-30%; S82: The dehydrated granular sludge is transferred to a drying device, the drying temperature is controlled at 60°C-80°C, and the drying time is 2-4 hours, until the sludge moisture content is reduced to 5%-10%; S83: Cooling the dried granular sludge to room temperature and sealing it with a packaging device to obtain a final aerobic granular sludge product.

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