High-efficiency aerobic granular sludge and preparation method and application thereof

Abstract

The application discloses high-efficiency aerobic granular sludge and a preparation method and application thereof, and belongs to the technical field of biological wastewater treatment. The application provides high-efficiency aerobic granular sludge and a preparation method thereof. The granular sludge is prepared by taking dewatered sludge with a water content of 60-75% in a wastewater plant as a raw material, and through steps of mud cake crushing, particle size screening, specific gravity air selection and elutriation activation, and has different particle sizes, a specific gravity of 1.04-1.10, a sphericity coefficient of 0.75-0.95, a consistency of 0.50-0.65 and a diameter distance of 1.05-1.50, so that the AGS system can be rapidly started. The high-performance granular sludge can be prepared only by simple processing operation. It has been verified that the granular sludge prepared by the application is added to an aerobic reactor, which helps to achieve the target requirements of rapid starting and stable operation of the AGS system.

Description

TECHNICAL FIELD

[0001] The present application relates to the sewage treatment technical field, especially to a kind of efficient aerobic granular sludge and its preparation method and application. BACKGROUND

[0002] The aerobic granular sludge (AGS) technology has excellent settling performance and a multi-layer structure from outside to inside, i.e., aerobic, anoxic and anaerobic. Therefore, the AGS technology can achieve simultaneous removal of COD, N and P in the aerobic section without additional sedimentation tank for sludge-water separation. According to research, the aerobic granular sludge can save nearly 70% of the land area, 20%-30% of the capital investment and operating energy consumption under the premise of ensuring that the effluent quality meets the standard. However, compared with the outstanding technical advantages, the aerobic granular sludge technology also has obvious shortcomings. Due to the lack of systematic granulation technology, the AGS technology has the disadvantages of slow granulation speed (about 30-60 days) and long system start-up period. Although researchers at home and abroad have explored and researched the cultivation method, formation process, granulation influencing factors and application of AGS for about 20 years, the above problems still restrict the engineering application process of the aerobic granular sludge in China.

[0003] Dewatered sludge is a solid waste of municipal sewage plants. At present, there is still a lack of important means for its proper treatment due to its huge output and high hazard. However, from the perspective of resource utilization, dry sludge is a biological waste product produced by dewatering the activated sludge after flocculation and concentration. It contains a large amount of extracellular polymeric substances and has the advantages of compact structure. At present, a large number of studies use it as a raw material for the preparation of biochar, and it is proved that the biochar prepared from dewatered sludge has excellent adsorption performance for phosphorus and antibiotics in wastewater. Dewatered sludge has strong biological potential. If dewatered sludge is used to prepare granular sludge and then added to the reactor, it may help to quickly start the aerobic granular sludge system. However, there is currently a lack of simple and efficient granular sludge granulation process. Therefore, it is necessary to develop a simple and efficient technical solution to process dewatered sludge to prepare aerobic granular sludge, tap its biological potential, shorten the start-up time of the AGS system, and promote the application of the technology. SUMMARY

[0004] To solve the problems of complicated granulation process, long start-up time and other bottlenecks of the aerobic granular sludge in the prior art, an efficient aerobic granular sludge and its preparation method and application are provided.

[0005] The first object of the present application is to provide an efficient aerobic granular sludge preparation method, which comprises the following steps:

[0006] Breaking the mud cake to obtain granular sludge;

[0007] The obtained granular sludge is screened, and a slow-release high-molecular coating adhesive is coated on the surface of the granular sludge, so that granular sludge containing a coating film on the surface is obtained.

[0008] The granular sludge containing a coating film on the surface is subjected to specific gravity screening, so that granular sludge with different particle sizes is obtained.

[0009] The granular sludge with different particle sizes obtained is subjected to elutriation and activation by using a nutrient activation solution containing a bacterial agent, so that the high-efficiency aerobic granular sludge is obtained.

[0010] In some embodiments of the present application, the moisture content of the mud cake is 60-75%; for example, it can be 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, etc., and any range value between any two numerical values.

[0011] The mud cake is obtained from the dewatered sludge collected from a municipal sewage plant;

[0012] The particle size of the granular sludge is 0.5-3 mm; for example, it can be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, etc., and any range value between any two numerical values.

[0013] In some embodiments of the present application, the mud cake is crushed by first cutting and crushing the block-shaped dried sludge, and then placing it on a stainless steel mesh plate containing 0.5-3 mm round holes, so that the crushed sludge passes through the 0.5-3 mm round holes through hydraulic extrusion of the extrusion plate to obtain large granular sludge.

[0014] In some embodiments of the present application, the sludge is placed in a particle size screening device during the screening process, and a slow-release high-molecular coating adhesive is sprayed at the same time, and then the sludge is screened by shaking, and the sludge passes through 12, 16, 20, 32, 48 and 80 mesh screens in turn, which have corresponding pore sizes of 1000-1400, 830-1000, 500-830 and 300-500 μm, respectively. The average particle size of the granular sludge obtained by screening. Among them, the mesh number of the screen can be flexibly selected and installed according to the target requirements, and the variable frequency shaking device can screen the preliminarily crushed granular sludge according to different particle sizes.

[0015] In some embodiments of the present application, the slow-release high-molecular coating adhesive comprises a sugar substance, calcium chloride, magnesium chloride and sodium chloride, and the mass ratio of the sugar substance, calcium chloride, magnesium chloride and sodium chloride is 1-2:0.1-0.2:0.3-0.5:0.4-0.5.

[0016] Further, the sugar substance is selected from one or more of sodium acetate, glucose, chitosan, maltose and starch, which can increase the viscosity of the sludge.

[0017] In the present application, 30-50 mL of slow-release high-molecular coating adhesive is uniformly sprayed per kilogram of granular sludge, so that the granular sludge can be fully coated.

[0018] In some embodiments of the present application, the coating film thickness of the granular sludge with a surface containing a coating film is 0.8-1.5 mm; the preparation of the coating film can ensure the structural strength of the granular sludge, prevent disintegration, and improve the stability of the system operation. In addition, the coating film can provide attachment sites for microorganisms, thereby enriching the functional microbial population on the surface of the granules.

[0019] The surface viscosity of the granular sludge with a surface containing a coating film is 10000-50000 mPa·s, exemplarily 10000 mPa·s, 20000 mPa·s, 30000 mPa·s, 40000 mPa·s, 50000 mPa·s, etc., and any range value between any two numerical values.

[0020] In some embodiments of the present application, the particle size proportion of the granular sludge with different particle sizes is 1.04-1.10, the sphericity coefficient is 0.75-0.95, the consistency is 0.50-0.65, and the span is 1.05-1.50.

[0021] In some embodiments of the present application, the nutrient activation solution of the bacteria-containing agent includes municipal wastewater, salt, and bacteria. The salt can be selected from conventional salts in the art, and can be selected from one or more of calcium chloride, magnesium chloride, and sodium chloride. In the present application, calcium chloride, magnesium chloride, and sodium chloride are used to form a core, strengthen the granular sludge skeleton structure, and the bacteria can effectively improve the target function of the granular sludge for wastewater treatment, thereby achieving efficient removal of carbon, nitrogen, and phosphorus pollutants.

[0022] In some embodiments of the present application, the salt is selected from one or more of sodium acetate, calcium chloride, ferric chloride, and magnesium sulfate; and the mass ratio of the calcium chloride, ferric chloride, and magnesium sulfate is 5-10:5-10:5-10.

[0023] The bacteria-containing agent is selected from one or more of nitrifying bacteria, denitrifying bacteria, and phosphorus-accumulating bacteria, and the mass ratio of the nitrifying bacteria, denitrifying bacteria, and phosphorus-accumulating bacteria is 2-5:1-3:1-3. When the granular sludge is formed, there is a gradient effect in the oxygen mass transfer from the outside to the inside, so the activities of different functional bacteria are affected differently.

[0024] Further, the bacterial strain of the nitrifying bacterial inoculant is not particularly limited and can be preferably selected from the group consisting of nitrite bacteria and nitrate bacteria. The nitrite bacteria include Nitrosomonas, Nitrosococcus, Nitrosospira, Nitrosolobus, and Nitrosospira. The nitrate bacteria include Nitrobacter, Nitrospina, Nitrococcus, and Nitrosospira.

[0025] Further, the bacterial strain of the denitrifying bacterial inoculant is not particularly limited and can be preferably selected from the group consisting of denitrifying bacteria, Thauera, and Xanthobacter.

[0026] In some embodiments of the present application, the sludge activation reactor is used in the washing activation process, and further includes aeration into the reactor, aeration for 60-90 min, sedimentation for 5-10 min, and repeated washing activation for multiple times. In the present application, through the activation process, the moisture content of the granular sludge is increased, and the carbon source and nitrogen source and other necessary nutrients are adsorbed, which is beneficial to the rapid activation and growth of the microorganisms in the granular sludge. At the same time, in the aeration process, the flocculent microorganisms not firmly adhered to the surface of the granular sludge are washed off. After multiple repeated activation steps, the biological aggregates with high adhesion capacity are screened, and then the granular sludge is formed.

[0027] In the present application, after the repeated washing activation steps for 3-5 times, the aerobic granular sludge with stable performance and suitable specific gravity and excellent settling performance is obtained. After the activation, the granular sludge with full granules, suitable specific gravity and restored biological activity is obtained. The activation process can improve the microbial activity in the granular sludge, and release the inorganic and organic flocculants in the dewatered sludge into the liquid phase. The re-flocculation of the active microorganisms can be realized through the re-contacting and collision of the flocculants on the surface of the granular sludge, and the structural strength of the aerobic granular sludge is improved.

[0028] The second object of the present application is to provide a high-efficiency aerobic granular sludge prepared by the method.

[0029] In some embodiments of the present application, the specific oxygen consumption rate (SOUR) of the high-efficiency aerobic granular sludge is 35-50 mg O2 / (g MLVSS·h), the nitrification or denitrification efficiency (SND) is 55-75%, and the settling velocity (V) is 90-160 m / h.

[0030] (SOUR) of 35-50 mg O2 / (g MLVSS·h), the nitrification or denitrification efficiency (SND) of 55-75%, and the settling velocity (V) of 90-160 m / h.

[0031] The present application further provides a high-efficiency aerobic granular sludge granulating device, which includes a particle size classifier, a specific gravity air classifier, and a sludge activation reactor arranged in sequence.

[0032] The sludge activation reactor includes:

[0033] An activated reactor body, which comprises a cone part arranged at the bottom and a feeding part connected above the cone part, the feeding part having an inlet for feeding the air-flown sludge;

[0034] An aeration assembly arranged in the cone part, which comprises an aeration pipe and an aeration head, one end of the aeration pipe extending into the internal space of the cone part and being connected with the aeration head;

[0035] A nutrient liquid input pipe, the outer wall of the cone part forming a nutrient liquid inlet, the nutrient liquid input pipe being connected with the nutrient liquid inlet to guide the nutrient liquid into the activated reactor body.

[0036] Further, an aeration valve is arranged on the aeration pipe;

[0037] A control valve is arranged on the nutrient liquid input pipe.

[0038] Further, a vent valve is arranged between the cone part and the feeding part;

[0039] A water decanting selection port is further arranged on the outer wall of the feeding part.

[0040] Further, the particle size classifier comprises a cylinder body and a variable frequency shaking assembly arranged on the cylinder body, a plurality of filter screens are arranged on the cylinder body along the axial direction of the cylinder body, and the pore size of each filter screen gradually decreases along the direction away from the opening of the cylinder body.

[0041] Further, the upper part of the cylinder body is formed in a cylindrical shape, the lower part of the cylinder body is formed in a conical shape, and a discharge valve is arranged at the bottom of the conical shape.

[0042] Further, a plurality of fixers are arranged on the outer wall of the cylinder body.

[0043] Further, the specific gravity air classifier comprises:

[0044] A specific gravity screening collection box, which comprises a plurality of specific gravity screening collection boxes arranged side by side;

[0045] A fan arranged on one side of the plurality of specific gravity screening collection boxes;

[0046] A feeding hopper arranged above the specific gravity screening collection boxes close to the side of the fan.

[0047] Further, the specific gravity air classifier further comprises:

[0048] A wind deflector, which comprises two wind deflectors arranged oppositely, and the wind deflectors extend along the arrangement direction of the plurality of specific gravity screening collection boxes.

[0049] Further, a specific gravity air classification feed pipe is further included;

[0050] The bottom of the particle size classifier forms a discharge valve, one end of the specific gravity air classification feed pipe is connected to the discharge valve, and the other end is connected to the feed hopper.

[0051] Further, two sludge activation feed pipes are further included;

[0052] The specific gravity screening collection box includes a first box body, a second box body, a third box body and a fourth box body arranged side by side in sequence along the air blowing direction of the air blower;

[0053] The second box body and the third box body are respectively connected to the feeding port of the sludge activation reactor through the sludge activation feed pipes.

[0054] The present application also provides how to use the high-efficiency aerobic granular sludge granulation device to prepare aerobic granular sludge, which includes a particle size classifier, a specific gravity air classifier and a sludge activation reactor arranged in sequence; the sludge activation reactor includes an activation reactor main body 24, which includes a cone portion arranged at the bottom and a feeding portion connected above the cone portion, the feeding portion has a feeding port for adding the air classified sludge; an aeration assembly is arranged in the cone portion, which includes an aeration pipe 19 and an aeration head 21, one end of the aeration pipe 19 extends into the internal space of the cone portion and is connected with the aeration head 21; the outer wall of the cone portion forms a nutrient liquid feeding port, and a nutrient liquid input pipe 17 is connected with the nutrient liquid feeding port to guide the nutrient liquid into the activation reactor main body 24. That is, the dewatered and dried sludge from the municipal sewage plant is used as the raw material, the sludge is crushed into a cake, and then sequentially subjected to particle size screening by the particle size classifier, specific gravity screening by the specific gravity air classifier, and elutriation and activation by the sludge activation reactor, so that the sludge with stable performance, appropriate specific gravity and excellent settling performance can be obtained.

[0055] The sludge activation reactor contains an elutriation and activation function, the granular sludge is mixed with the prepared nutrient liquid and added into the sludge activation reactor, which can realize the awakening and activation function of the microorganisms inside the granular sludge, and at the same time, the light flocs falling off from the surface of the granular sludge are elutriated. The aeration assembly arranged in the sludge activation reactor can make the oxygen in the air transfer to the mixed liquid and be utilized by the microorganisms, thereby improving the mass transfer efficiency.

[0056] The above technical solutions of the present application have the following advantages compared with the prior art:

[0057] (1) The present application uses the dewatered and dried sludge from the municipal sewage plant as the raw material, and develops a high-performance aerobic granular sludge preparation process, which does not require complex pretreatment methods such as high temperature, low temperature or ultrasonic. Compared with the granulation technology on the market, the operation process is greatly simplified.

[0058] (2) Users can replace the screen according to the needs, to prepare different particle size of granular sludge, realize different particle size and specific gravity sludge compounding, compared to the natural particle size of sludge particle size control and uncertainty, has the technical advantage of controlling particle size grading.

[0059] (3) The present application can be through the change of air supply flow of fan of air separation device flexible adjustment sludge specific gravity air separation, and then the light and heavy sludge are excluded, to ensure that the preparation of granular sludge physical and chemical properties stable, and in the process of aeration expansion suspended requirements and the need for rapid sedimentation in the process of sedimentation.

[0060] (4) The present application contains washing activation function, after mixing granulation granular sludge and the prepared nutrient solution is added to the washing activation device, can realize the awakening activation function of granular sludge internal microorganism, at the same time, the light floc on the surface of granular sludge is washed out.

[0061] (5) The granular sludge prepared by the present application can shorten the start-up time of aerobic granular sludge system to 3-5 days, and can quickly realize the simultaneous nitrification and denitrification effect, and the water quality after treatment meets the first level A standard of urban sewage treatment discharge standard, and the sludge performance is stable, the specific gravity is appropriate, and the settling performance is excellent. BRIEF DESCRIPTION OF DRAWINGS

[0062] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to the specific embodiments of the present application and in conjunction with the drawings, wherein,

[0063] Figure 1 is the process flow chart of the present application;

[0064] Figure 2 is the conventional photograph and 40 times microscope shooting result of the granulation sludge in the aerobic granular sludge system;

[0065] Figure 3 is the scanning electron microscope shooting result of the granulation sludge in the aerobic granular sludge system;

[0066] Figure 4 is the particle size distribution result of the granulation sludge in the aerobic granular sludge system on the 15th day;

[0067] Figure 5 is the pollutant treatment efficiency of the granulation sludge in the aerobic granular sludge system.

[0068] Figure 6 is the structure schematic view of the particle size classifier of the high-efficiency aerobic granular sludge granulation device of the embodiment of the present application;

[0069] Figure 7The structure diagram of the specific gravity air separator of the high-efficiency aerobic granular sludge granulation device of the embodiment of the present application;

[0070] Figure 8 The structure diagram of the sludge activation reactor of the high-efficiency aerobic granular sludge granulation device of the embodiment of the present application.

[0071] Description of the drawing: 1. Cylinder; 2. 12-mesh screen; 3. Fixer; 4. 16-mesh screen; 5. 20-mesh screen; 6. 32-mesh screen; 7. 48-mesh screen; 8. Discharge valve; 9. Spraying head; 10. Fan; 11. First box; 12. Second box; 13. Third box; 14. Fourth box; 15. Wind deflector; 16. Feeding hopper; 17. Nutrient liquid input pipe; 18. Control valve; 19. Aeration pipe; 20. Aeration valve; 21. Aeration head; 22. Vent valve; 23. Decanting selection port; 24. Activation reactor main body. DETAILED DESCRIPTION

[0072] The present application will be further described below in conjunction with the drawings and specific examples, so that those skilled in the art can better understand the present application and implement it. The examples are not intended to limit the present application. The strains used in the present application are all conventional strains in the art, which can be commercially available or obtained by screening and enrichment according to the literature.

[0073] Example 1

[0074] (1) 5 kg of dried sludge was taken from a municipal sewage plant, and the water content was measured to be 65.8%. The sludge cake was crushed into blocks by a crusher, and then the crushed sludge blocks were crushed into granular sludge with a particle size of 0.5-3 mm by a sludge cake crusher for standby. The mass of the granular sludge after weighing and screening was 4.32 kg.

[0075] (2) The screened granular sludge was added to the sizer for screening for 1 h. In the screening process, a slow-release high-molecular coating adhesive composed of 0.4 g of starch sugar, 0.04 g of calcium chloride, 0.1 g of magnesium chloride and 0.1 g of sodium chloride and 200 ml of municipal sewage was sprayed onto the surface of the granular sludge. In the screening process, the granular sludge passed through 12-mesh screen 2, 16-mesh screen 4, 20-mesh screen 5, 32-mesh screen 6 and 48-mesh screen 7, respectively.

[0076] (3) After the screening was completed, the 16-mesh screen 4 was removed, and granular sludge with an average particle size of 1000-1400 μm was obtained, and the weighing result was 0.39 kg. Then the sludge with this particle size was added to the feeding hopper 16 at the top of the air separator, and the air quantity of the fan 10 of the air separator was set to 20-25 L / min. The specific gravity screening collection box 11

[0077] (First box) and the particle sludge in the specific gravity screening collection box 14 (fourth box) is discarded; the particle sludge in the specific gravity screening collection box 12 (second box) and the specific gravity screening collection box 13 (third box) is collected to obtain the particle sludge with the average particle size of 1000-1400 μm, the specific gravity of 1.04-1.10, the sphericity coefficient of 0.75-0.9, the uniformity of 0.50-0.65, and the span of 1.05-1.50.

[0078] (4) The 20-mesh screen 5 is removed to obtain the particle sludge with the average particle size of 830-1000 μm, and the weighing result is 0.39 kg, then the particle sludge with the particle size is added to the top feeding hopper 16 of the air separator, the air volume of the air fan 10 of the air separator is set to 15-20 L / min, the particle sludge in the specific gravity screening collection box 11 (first box) and the specific gravity screening collection box 14 (fourth box) is discarded; the particle sludge in the specific gravity screening collection box 12 (second box) and the specific gravity screening collection box 13 (third box) is collected to obtain the particle sludge with the average particle size of 830-1000 μm, the specific gravity of 1.04-1.10, the sphericity coefficient of 0.75-0.9, the uniformity of 0.50-0.65, and the span of 1.05-1.50.

[0079] (5) The 32-mesh screen 6 is removed to obtain the particle sludge with the average particle size of 500-830 μm, and the weighing result is 1.03 kg, then the particle sludge with the particle size is added to the top feeding hopper 16 of the air separator, the air volume of the air fan 10 of the air separator is set to 12-15 L / min, the particle sludge in the specific gravity screening collection box 11 (first box) and the specific gravity screening collection box 14 (fourth box) is discarded; the particle sludge in the specific gravity screening collection box 12 (second box) and the specific gravity screening collection box 13 (third box) is collected to obtain the particle sludge with the average particle size of 500-830 μm, the specific gravity of 1.04-1.10, the sphericity coefficient of 0.75-0.9, the uniformity of 0.50-0.65, and the span of 1.05-1.50.

[0080] (6) Remove the 48-mesh screen 7 to obtain granular sludge with an average particle size of 300-500 μm, and the weighing result is 1.09 kg. Then, the sludge of this particle size is added to the top feed hopper 16 of the air separator, the air volume of the air separator fan 10 is set to 10-12 L / min, and the granular sludge in the specific gravity screening collection tank 11 (first tank body) and the specific gravity screening collection tank 14 (fourth tank body) is discarded; the granular sludge in the specific gravity screening collection tank 12 (second tank body) and the specific gravity screening collection tank 13 (third tank body) is collected to obtain granular sludge with an average particle size of 300-500 μm, a specific gravity of 1.04-1.10, a sphericity coefficient of 0.75-0.9, a uniformity of 0.50-0.65, and a span of 1.05-1.50.

[0081] (7) To verify the sludge preparation effect, granular sludge with an average particle size of 1000-1400 μm and 830-1000 μm, a specific gravity of 1.04-1.10, and a sphericity coefficient of 0.75-0.9 is respectively added to a 3L SBR reactor to verify the treatment effect.

[0082] (8) Prepare 10L municipal sewage, and add 1g sodium acetate, 2.5mg nitrifying bacteria agent (Actinobacteriota, Chloroflexi and Nitrospirota abundance ratio of 95% or more), 2.5mg denitrifying bacteria agent (Firmicutes, Acidobacteria and Proteobacteria abundance ratio of 95% or more), 2.5mg polyphosphorus bacteria agent (Penicillium, Aspergillus and Alternaria abundance ratio of 95% or more), 7.5mg calcium chloride, 7.5mg ferric chloride and 7.5mg magnesium sulfate to configure a compound nutrient activation liquid.

[0083] (9) The granular sludge obtained in steps (3) and (4) is added to the washing and activation device, the nutrient liquid input valve 18 is opened to inject the compound nutrient activation liquid, and the aeration pump is opened for aeration for 60 minutes (air), and then the water decanting selection valve 23 is opened to discharge the suspended impurities released by the granular sludge. The sludge is washed and activated for 3 times in the above manner, and finally the required aerobic granular sludge is obtained.

[0084] (10) The obtained finished product aerobic granular sludge is added to the actual operation of the biochemical reactor to verify the effect of the granulated aerobic granular sludge. After the prepared aerobic granular sludge is operated for 3 days, the average specific oxygen uptake rate (SOUR) reaches 28.3 mg O2 / (g MLVSS·h), the average simultaneous nitrification and denitrification efficiency (SND) reaches 72.3%, and the average settling velocity (V) reaches 127 m / h. As shown in FIG. 10, the pictures of the finished product of the aerobic granular sludge with a particle size of 1000-1400 μm and 830-1000 μm are taken by a 40 times microscope, respectively. Figure 2 Figure 3 The pictures of the aerobic granular sludge with a particle size of 1000-1400 μm and 830-1000 μm under a scanning electron microscope on the 10th day are shown in FIG. 11. Figure 4 The particle size distribution diagrams of the aerobic granular sludge with a particle size of 1000-1400 μm and 830-1000 μm are shown in FIG. 12. Figure 5 The COD and total nitrogen results of the influent and effluent of the aerobic granular sludge with a particle size of 1000-1400 μm and 830-1000 μm are shown in FIG. 13. The system can be stably operated within 3 days, the effluent COD is less than 50 mg / L, and the TN is less than 15 mg / L.

[0085] Example 2

[0086] (1) 500 kg of dried sludge is taken from a municipal sewage plant, and the average moisture content is measured to be 67.2%. The sludge cake is crushed by a crusher, and then the crushed sludge blocks are crushed into granular sludge with a particle size of 0.5-3 mm by using a sludge cake crusher for standby. The mass of the granular sludge after screening is measured to be 415.8 kg.

[0087] (2) In order to obtain granular sludge with a target particle size of 1000, 830 and 500 μm, 12, 16, 20 and 32 mesh screens are selected, and the granular sludge after crushing in step (1) is added to the screen classifier for screening for 3 hours. At the same time, a slow-release high-molecular coating adhesive is sprayed on the surface of the granular sludge during the screening process, which is obtained by compounding 320 g of starch, 32 g of calcium chloride, 80 g of magnesium chloride and 80 g of sodium chloride with 16 L of municipal sewage. The surface viscosity of the screened granular sludge reaches 35379 mPa·s.

[0088] (3) After the screening is completed, the 16 mesh screen is removed, and granular sludge with an average particle size of 1400 μm is obtained, and the weighing result is 190.9 kg. Then the sludge with this particle size is added to the top feed inlet of the air separator, and the air quantity of the air separator fan is set to 20-25 L / min. The granular sludge with a specific gravity of 1.04-1.10 is retained, and the granular sludge with a specific gravity greater than 1.10 and less than 1.04 is discarded. The required granular sludge is obtained, and the mass is 135.2 kg.

[0089] ​(4) Take off the 20-mesh screen to obtain granular sludge with an average particle size of 1000 μm, and the weighing result is 101.7 kg. Then the sludge of this particle size is added to the top feed inlet of the air separator, and the air volume of the air separator fan is set to 15-20 L / min. The granular sludge with a specific gravity between 1.04-1.10 is retained, and the granular sludge with a specific gravity greater than 1.10 and less than 1.04 is discarded, and 83.5 kg of granular sludge meeting the requirements is obtained.

[0090] (5) Open the collection bucket below the 32-mesh screen to obtain granular sludge with an average particle size of 500 μm, and the weighing result is 97.6 kg. Then the sludge of this particle size is added to the top feed inlet of the air separator, and the air volume of the air separator fan is set to 12-15 L / min. The granular sludge with a specific gravity between 1.04-1.10 is retained, and the granular sludge with a specific gravity greater than 1.10 and less than 1.04 is discarded, and 81.6 kg of granular sludge meeting the requirements is obtained.

[0091] (6) Prepare 3 tons of municipal sewage, and add 3000 g of sodium acetate, 7.5 g of nitrifying bacteria agent, 7.5 g of denitrifying bacteria agent, 7.5 g of phosphorus accumulating bacteria agent, 22.5 g of calcium chloride, 22.5 g of ferric chloride and 22.5 g of magnesium sulfate, and mix uniformly to prepare a compound nutrient activation solution.

[0092] (7) Mix the granular sludge obtained in steps (3), (4) and (5) uniformly and add it to the volume of 3 m 3

[0093] (8) Start the SBR aerobic granular sludge system reactor for sewage treatment, and analyze the physicochemical properties of the aerobic granular sludge, the effluent quality and the operation efficiency. After 5 days of operation of the prepared aerobic granular sludge, the average specific oxygen uptake rate (SOUR) reaches 26.9 mg O2 / (g MLVSS·h), the average simultaneous nitrification and denitrification efficiency (SND) reaches 75.6%, and the average settling velocity (V) reaches 119 m / h. The effluent quality of the system can reach the Urban Sewage Discharge Standard (Class A) within 5 days, i.e. the effluent COD < 50 mg / L and TN < 15 mg / L.

[0094] Comparative Example 1

[0095] Similar to the method of Example 1, the difference is that there is no step (2) of coating with a slow-release high molecular coating adhesive.

[0096] ​Comparative Example 1: In the granulation process, the granular sludge coated with the slow-release high molecular binder in step (2) was loose and easy to disintegrate. According to the performance parameter test results, the sphericity coefficient of the granular sludge was between 0.45 and 0.65, the consistency was between 0.62 and 0.85, and the span was between 1.35 and 1.72. The granular sludge prepared without step (2) had obvious deficiencies in performance parameters and operation efficiency.

[0097] Comparative Example 2

[0098] Similar to the method of Example 1, the difference is that the activation with the nutrient activation solution in steps (6) and (7) is omitted.

[0099] Comparative Example 2: In the granulation process, the granular sludge activated with the nutrient activation solution in steps (6) and (7) had problems such as slow recovery of treatment efficiency and long adaptation period. According to the laboratory comparison experiment, the effluent water quality of the granular sludge system without steps (6) and (7) reached the Urban Sewage Discharge Standard (Class A) in 15 days, and the average specific oxygen uptake rate (SOUR) decreased to 20.6 mg O2 / (g MLVSS·h), and the average simultaneous nitrification and denitrification efficiency (SND) decreased to 55.8%.

[0100] Obviously, the above examples are only examples for the sake of clarity, and are not limitations on the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. It is not necessary and impossible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for preparing high-efficiency aerobic granular sludge, characterized by, It comprises the following steps: breaking the mud cake to obtain granular sludge; screening the obtained granular sludge and coating a slow-release high-molecular coating adhesive on the surface of the granular sludge to obtain granular sludge containing a coating film on the surface; screening the granular sludge containing a coating film on the surface by specific gravity to obtain granular sludge of different particle sizes; washing and activating the obtained granular sludge of different particle sizes by using a nutrient activation solution containing a bacterial agent to obtain the high-efficiency aerobic granular sludge; the slow-release high-molecular coating adhesive comprises sugar substances, calcium chloride, magnesium chloride and sodium chloride, and the mass ratio of the sugar substances, calcium chloride, magnesium chloride and sodium chloride is 1-2:0.1-0.2:0.3-0.5:0.4-0.5; the nutrient activation solution containing a bacterial agent comprises municipal sewage, salt and a bacterial agent; the salt is selected from one or more of calcium chloride, ferric chloride and magnesium sulfate; the mass ratio of the calcium chloride, ferric chloride and magnesium sulfate is 5-10:5-10:5-10; the bacterial agent is selected from one or more of nitrifying bacterial agents, denitrifying bacterial agents and polyphosphorus bacterial agents; the mass ratio of the nitrifying bacterial agents, denitrifying bacterial agents and polyphosphorus bacterial agents is 2-5:1-3:1-3.

2. The method according to claim 1, wherein the method is characterized by, The water content of the mud cake is 60-75%, and the mud cake is obtained from the dewatered sludge collected from a municipal sewage plant.

3. The method according to claim 1, wherein the method is characterized by, The particle size of the granular sludge is 0.5-3 mm.

4. The method according to claim 1, wherein the method is characterized by, The thickness of the coating film of the granular sludge containing a coating film on the surface is 0.8-1.5 mm.

5. The method according to claim 1, wherein the method is characterized by, The surface viscosity of the granular sludge containing a coating film on the surface is 10,000-50,000 mPa·s.

6. The method according to claim 1, wherein the method is characterized by, The particle size ratio of the granular sludge of different particle sizes is 1.04-1.10, the sphericity coefficient is 0.75-0.95, the consistency is 0.50-0.65, and the span is 1.05-1.

50.

7. The method according to claim 1, wherein the method is characterized by, A sludge activation reactor is used in the washing and activation process, and the process further comprises aerating the reactor, aerating for 60-90 min, precipitating for 5-10 min, and repeating the washing and activation multiple times.

8. A high-rate aerobic granular sludge, characterized by, The high-efficiency aerobic granular sludge is prepared by the method of any one of claims 1-7.

9. The high-rate aerobic granular sludge according to claim 8, characterized in that, The specific oxygen consumption rate of the high-efficiency aerobic granular sludge reaches 35-50 mg O2 / (g MLVSS·h), the nitrification or denitrification efficiency reaches 55-75%, and the settling velocity (V) reaches 90-160 m / h.

10. The high-efficiency aerobic granular sludge of claim 8 or 9 is used in a biochemical treatment unit in sewage treatment.

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