Rapid culture method for aerobic granular sludge

Abstract

The invention relates to the technical field of sewage treatment, in particular to an aerobic granular sludge rapid culture method which comprises the following steps: S1, dewatering excess sludge of a municipal sewage treatment plant; s2, adding activated carbon and stirring to form a mixture A; s3, adding a pre-prepared nutrient solution into the mixture A; s4, inducing the sludge to be granulated, so that the sludge gradually forms a granular structure; s5, regularly adding a solution containing Ca < 2 + > and Mg < 2 + > into the preliminary particle structure; s6, adjusting the hydraulic retention time in the reactor to form a mixture of granular sludge and suspended sludge; s7, collecting granular sludge meeting the particle size requirement; s8, carrying out dehydration and drying treatment on the collected granular sludge; according to the invention, the overall efficiency of sewage treatment is improved by optimizing the sludge granulation process, accurately controlling various parameters, simplifying the operation steps, shortening the granulation time and enhancing the stability of sludge particles.

Description

Technical Field

[0001] The 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, and reduce problems such as sludge swelling and poor sedimentation performance.

[0003] However, in practical applications, how to efficiently and quickly cultivate high-quality aerobic granular sludge still faces many challenges, especially when treating high-concentration organic wastewater and municipal sewage, the formation time of granular sludge is long, and the granule stability is poor, which affects the treatment effect. Therefore, efficient granular cultivation of sludge, especially maintaining the stability of granular sludge under different environmental conditions, has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] Based on the above purpose, 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: adding the sludge treated by S1 into the reactor and adding 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 Mg2+ solution, and continue stirring 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: Dehydrating and drying the collected granular sludge 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 by a mechanical filter press to reduce the sludge moisture content to 60%-70%;

[0016] S12: placing the preliminarily dehydrated sludge 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 treatment on the screened sludge to reduce the moisture content of the sludge 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: adding the sludge treated in S1 evenly into the reactor through the conveying equipment, and controlling the amount of sludge added so that it occupies 40%-60% of the reactor volume;

[0021] S22: Adding 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-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 in a nitrogen-phosphorus mass ratio of 10:1. The trace elements are added to the nutrient solution in an amount of 0.1%-0.5% of the total liquid volume, and the temperature of the prepared nutrient solution is controlled at 20°C-30°C.

[0024] Optionally, the S3 specifically includes:

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

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

[0027] S33: Use an acid-base regulator to adjust the pH value in the reactor to 6.5-8.0, and after completion 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 4-8 mg / L;

[0030] S42: Start the stirring device in the reactor and operate it in an intermittent stirring mode. The stirring time is 30-40 minutes each time, and the stirring is performed every 1-2 hours. The stirring speed is maintained 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 Mg2+ mixed solution, the solution contains Ca 2 The mass ratio of Ca + to Mg2+ is 2:1, 2 + concentration is 50-100 mg / L, Mg2+ 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 Mg2+ solution, start the stirring device for uniform stirring, keep the stirring speed at 50-80rpm, 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 discharge 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 6-8g / L. When the concentration exceeds 8g / L, about 5% of the sludge is discharged every 12 hours through the sludge discharge system. When the concentration is lower than 6g / 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, aerobic cultivation continues, 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, and the mesh 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, and 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 drops to 5%-10%;

[0045] S83: The dried granular sludge is cooled to room temperature and sealed and packaged by packaging equipment 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, the precise control of dissolved oxygen and Ca 2 The regular addition of Mg2+ and Mg2+ realizes the rapid induction and enhancement of sludge granulation. Compared with the prior art, the present invention simplifies the operation steps during the cultivation process, and through reasonable parameter regulation, significantly shortens the sludge granulation time, improves the sludge particle stability, and makes it more suitable for the treatment of high-concentration organic wastewater.

[0048] The present invention adopts a staged sludge treatment scheme to effectively control each link of sludge dehydration, stirring, granulation, screening and dehydration and drying, ensuring the connection and consistency between each step, so that the cultivated granular sludge has excellent particle size distribution and strong mechanical stability, solving the problem of instability of granular sludge in the prior art and improving 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0051] Figure 2 This is a 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 in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternatives to implement some known technologies; and the accompanying drawings are only for more specific description of the embodiments, and are not intended to specifically limit the present invention.

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

[0054] In general, a term can be understood, at least in part, from its 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 the municipal sewage treatment plant and remove impurities and excess water to make the sludge suitable for subsequent treatment;

[0058] S2: Add the sludge treated by S1 into the reactor, add activated carbon and stir to form mixture A, and then enter the nutrient addition stage after stirring evenly;

[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 Mg2+ solution, continue stirring to enhance the aggregation of microorganisms and the stability of particle structure, and ensure 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: Dehydrating and drying the collected granular sludge 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: placing the preliminarily dehydrated sludge 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 treatment on the screened sludge to reduce the moisture content of the sludge 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: adding the sludge treated in S1 evenly into the reactor through the conveying equipment, and controlling the amount of sludge added so that it occupies 50% of the reactor volume;

[0072] S22: Add activated carbon into 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, and then enter the next stage.

[0074] 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. The nutrient solution is prepared specifically according to a mass ratio of nitrogen to phosphorus of 10:1. The trace elements are added to the nutrient solution according to 0.3% of the total liquid volume, and 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 the mixture A;

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

[0079] S4 specifically includes:

[0080] S41: Control the dissolved oxygen concentration in the reactor through the dissolved oxygen monitoring device and control the concentration range within 6 mg / L, continuously monitor and adjust the aeration volume 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. The stirring time is 35 minutes each time, and the stirring is performed once every 1.5 hours. The stirring speed is maintained at 70 rpm until the sludge forms a stable particle structure.

[0082] S5 specifically includes:

[0083] S51: Ca is added to the initial particle structure in the reactor every 36 hours 2 + and Mg2+ mixed solution, the solution contains Ca 2 The mass ratio of Ca + to Mg2+ is 2:1, 2 + concentration is 75 mg / L, Mg2+ concentration is 37.5 mg / L, and the addition amount is 8% of the total liquid volume of the reactor;

[0084] S52: Each time Ca is added 2+ and Mg2+ solution, start the stirring device for uniform stirring, keep the stirring speed at 70 rpm, and the stirring time is 30 min 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 7g / L. When the concentration exceeds 8g / L, about 5% of the sludge is discharged every 12 hours through the sludge discharge system. When the concentration is lower than 6g / 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, aerobic cultivation continues, and 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: starting the screening device to separate the granular sludge from the suspended sludge, and the sieve hole 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 through 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 rotation speed to 1800 rpm, and continuing the dehydration time 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, the drying time is 3 hours, until the sludge moisture content drops to 8%;

[0096] S83: The dried granular sludge is cooled to room temperature and sealed and packaged by packaging equipment to obtain a final aerobic granular sludge product.

[0097] Example 2

[0098] S1: The residual sludge from the municipal sewage treatment plant is dehydrated by a mechanical filter press to reduce the moisture content of the sludge to 60%; the sludge after preliminary dehydration is then screened to remove impurities and non-organic matter with a particle size greater than 5 mm; the screened sludge is subjected to secondary centrifugal dehydration to reduce the moisture content to 40%; and finally the sludge is dried at low temperature by 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, the stirring speed is set to 50rpm, and the stirring time is 20 minutes, until the sludge and the activated carbon are fully mixed to form a mixture A;

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

[0101] S4: Control the dissolved oxygen concentration in the reactor at 4 mg / L through a dissolved oxygen monitoring device; start intermittent stirring, the stirring time is 30 minutes each time, stirring is performed once every 1 hour, and the stirring speed is set to 50 rpm until a stable particle structure is formed;

[0102] S5: Add Ca to the particle structure every 24 hours 2 + and Mg2+ mixed solution, the solution contains Ca 2 The mass ratio of Ca + to Mg2+ is 2:1, of which Ca 2 + concentration is 50mg / L, Mg2+ concentration is 25mg / L, and the amount added is 5% of the total liquid volume in the reactor; the stirring speed is maintained at 50rpm, and the stirring time is 30 minutes;

[0103] S6: By adjusting the water inlet and drainage system, the hydraulic retention time is controlled to be 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, the screen size is 1 mm, the screening time is 10 minutes, separate the granular sludge, collect 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 1500rpm, 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%, and seal and package after cooling to room temperature.

[0106] Example 3

[0107] S1: The residual sludge from the municipal sewage treatment plant is dehydrated by a mechanical filter press to reduce the moisture content of the sludge to 70%; the sludge after preliminary dehydration is then screened to remove impurities and non-organic matter with a particle size greater than 5mm; the screened sludge is subjected to secondary centrifugal dehydration to reduce the moisture content to 50%; and finally the sludge is dried at low temperature by 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, the stirring speed is set to 100 rpm, and the stirring time is 30 minutes, until the sludge and the activated carbon are fully mixed to form a mixture A;

[0109] S3: adding 10% of the mass of a pre-prepared nutrient solution to the mixture A, wherein the nutrient solution is prepared by ammonium nitrate and potassium dihydrogen phosphate in a mass ratio of 10:1 and contains 0.5% sodium chloride as a trace element, and the temperature of the nutrient solution is controlled at 30°C; starting a stirring device, controlling the stirring speed at 80 rpm, and stirring for 20 minutes; then adjusting 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, the stirring time is 40 minutes each time, stirring is performed once every 2 hours, and the stirring speed is set to 100 rpm until a stable particle structure is formed;

[0111] S5: Add Ca to the particle structure every 48 hours 2 + and Mg2+ mixed solution, the solution contains Ca 2The mass ratio of Ca + to Mg2+ is 2:1, of which Ca 2 + concentration is 100 mg / L, Mg2+ concentration is 50 mg / L, and the amount added is 10% of the total liquid volume in 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 system, the hydraulic retention time is controlled to be 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, the screen size is 2 mm, the screening time is 15 minutes, separate the granular sludge, collect and store it in a prepared container for later use;

[0114] S8: Place the granular sludge in a centrifugal dehydration device, set the speed to 2000rpm, 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%, and seal and package after cooling to room temperature.

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

[0116] Compare Projects 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 that although the sludge moisture content (8%) and particle size (1.5 mm) of Example 1 are not the lowest or smallest, they are still moderate in these two indicators and are suitable for 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 compared with 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] It can be seen from Table 2 that the particle settling velocity of Example 1 is 1.8 cm / min, indicating that the particle settling is fast, 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 particle 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 a 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 a relatively low cost. From the above data, it can be seen that Example 1 shows the best effect in terms of particle settling velocity, sludge density, biological activity, ammonia nitrogen and phosphorus removal rates, and has a lower operating cost, and is the best implementation scheme as a whole.

[0122] The present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without the description of these details. In addition, in order to avoid unnecessary confusion about the essence of the present invention, well-known methods, processes, procedures, components and circuits are not 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 principle of the present invention. These improvements and modifications should also be regarded as 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: adding the sludge treated by S1 into the reactor and adding 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 Mg2+ solution, and continue stirring 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 the final aerobic granular sludge product.

2. The method for rapid cultivation of aerobic granular sludge according to claim 1, characterized in that: The S1 specifically includes: 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 60%-70%; S12: placing the preliminarily dehydrated sludge in a screening device to remove impurities and non-organic matter with a particle size greater than 5 mm; S13: performing secondary centrifugal dehydration treatment on the screened sludge to reduce the moisture content of the sludge 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%.

3. The method for rapid cultivation of aerobic granular sludge according to claim 1, characterized in that: The S2 specifically includes: S21: adding the sludge treated in S1 evenly into the reactor through the conveying equipment, and controlling the amount of sludge added so that it occupies 40%-60% of the reactor volume; S22: Adding 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.

4. The method for rapid cultivation of aerobic granular sludge according to claim 1, characterized in that: The pre-formulated nutrient solution comprises 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 specifically according to a mass ratio of nitrogen to phosphorus of 10:

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

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

6. 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 4-8 mg / L; S42: Start the stirring device in the reactor and operate it in an intermittent stirring mode. The stirring time is 30-40 minutes each time, and the stirring is performed every 1-2 hours. The stirring speed is maintained at 50-100 rpm until the sludge forms a stable particle structure.

7. 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 Mg2+ mixed solution, the solution contains Ca 2 The mass ratio of Ca + to Mg2+ is 2:1, 2 + concentration is 50-100 mg / L, Mg2+ 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 Mg2+ solution, start the stirring device for uniform stirring, keep the stirring speed at 50-80rpm, and the stirring time is 30 minutes to ensure that the solution is evenly distributed.

8. The method for rapid cultivation of aerobic granular sludge according to claim 1, characterized in that: The S6 specifically includes: S61: By adjusting the inlet flow rate and the discharge 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 6-8g / L. When the concentration exceeds 8g / L, about 5% of the sludge is discharged every 12 hours through the sludge discharge system. When the concentration is lower than 6g / 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, aerobic cultivation continues, 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.

9. 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, and the mesh 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, and 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.

10. 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 drops to 5%-10%; S83: The dried granular sludge is cooled to room temperature and sealed and packaged by packaging equipment to obtain a final aerobic granular sludge product.

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