A decalcification and regeneration device and method for calcified anaerobic granular sludge

Abstract

The present invention relates to a decalcification and regeneration device and method for calcified anaerobic granular sludge. The decalcification and regeneration device comprises, from top to bottom, a decalcification zone, a degassing zone and a cultivation zone. A drug inlet and a feed inlet are provided on the side of the decalcification zone, respectively used to input a decalcifying agent and calcified anaerobic granular sludge. An aeration pipe and a stirrer are provided at the bottom of the decalcification zone, used to promote contact and reaction between the decalcifying agent and the calcified anaerobic granular sludge. An openable and closable gate is provided below the stirrer and the aeration pipe, used to discharge the decalcified granular sludge into the degassing zone. A guide rail and a stirring rod are provided at the top of the degassing zone, and the stirring rod moves along the guide rail to stir the granular sludge in the degassing zone, thereby promoting the removal of bubbles on the surface of the granular sludge and in the micropores. A first discharge port is provided at the bottom of the degassing zone, used to input and discharge the degassed granular sludge into the cultivation zone. The cultivation zone is provided with a sewage inlet, used to input sewage and activated sludge and cultivate the degassed granular sludge.

Description

Technical Field

[0001] The present invention belongs to the technical field of anaerobic granular sludge decalcification, and in particular relates to a decalcification and regeneration device and method for calcified anaerobic granular sludge. Background Art

[0002] Anaerobic biochemical treatment is an important treatment method in industrial wastewater treatment, particularly in industries such as waste paper pulping, food processing, landfill leachate, and fermentation wastewater. A key component of anaerobic reactors / tanks is anaerobic granular sludge. Anaerobic granular sludge is primarily composed of calcium carbonate, which adsorbs anaerobic bacterial flora and sludge to form granules. During anaerobic reactor operation, if the calcium ion concentration in the wastewater is high, precipitated calcium salts will form. These salts will deposit on the surface of the granular sludge or enter the interior through the granular micropores, forming scale nucleations. This makes the surface or interior of the granular sludge relatively solid. After prolonged operation, the granular sludge feels like pebbles when touched. This phenomenon is known as anaerobic granular sludge calcification. Calcified anaerobic granular sludge isolates microorganisms from substrates in the wastewater, hindering their growth and metabolism, resulting in decreased or even inactivated sludge activity. Furthermore, due to its heavy weight, calcified granular sludge can accumulate between the reactor wall and the water distributor, forming dead zones and affecting the anaerobic internal circulation. Currently, the calcified granular sludge can be discharged and then regenerated. However, how to efficiently decalcify the calcified granular sludge and increase the amount of microbial attachment again is a problem faced by those skilled in the art. Summary of the Invention

[0003] To address the above-mentioned problems, the present invention provides a decalcification and regeneration device and method for calcified anaerobic granular sludge. In a first aspect, the decalcification and regeneration device for calcified anaerobic granular sludge comprises, from top to bottom, a decalcification zone, a degassing zone, and a culture zone. The side of the decalcification zone is provided with a drug inlet and a feed inlet for inputting a decalcifying agent and calcified anaerobic granular sludge, respectively. The bottom of the decalcification zone is provided with an aeration pipe and an agitator for promoting contact and reaction between the decalcifying agent and the calcified anaerobic granular sludge. An openable and closable gate is provided below the agitator and the aeration pipe for discharging the decalcified granular sludge into the degassing zone.

[0004] The upper part of the degassing zone is provided with a guide rail and a stirring rod. The stirring rod moves along the guide rail to stir the granular sludge in the degassing zone, promoting the removal of bubbles on the surface of the granular sludge and in the micropores. The bottom of the degassing zone is provided with a first discharge port for inputting the degassed granular sludge into the culture zone.

[0005] The culture area is provided with a sewage inlet for inputting sewage and activated sludge and cultivating degassed granular sludge.

[0006] Optionally, the decalcification zone includes a lower reaction zone and an upper separation zone, a first horizontal partition is provided between the reaction zone and the separation zone, a second discharge port is provided on the side wall of the bottom of the separation zone, and the second discharge port is connected to the nutrient pre-storage tank through a pipeline; a drug inlet and a feed port are provided on the side of the top of the reaction zone, the lower part of the reaction zone is a cone with a larger upper part and a smaller lower part, an agitator and an aeration pipe are provided at the bottom of the cone, the aeration pipe is provided below the agitator, and an openable and closable gate is provided below the aeration pipe.

[0007] Further optionally, the mesh size of the first screen is smaller than the average particle size of the calcified anaerobic granular sludge, so that the calcified anaerobic granular sludge is intercepted in the reaction zone and continues to react with the decalcifying agent. The decalcified granular sludge and the precipitate obtained by the reaction can enter the separation zone under the action of stirring and aeration.

[0008] Further optionally, a horizontal fixing frame is provided below the aeration tube, the aeration tube is mounted on the fixing frame and is evenly distributed below the agitator; the agitator is set horizontally as a whole, and the motor of the agitator can be set at the center of the fixing frame or above the outside of the decalcification regeneration device. The rotating shaft of the motor is set vertically and connected to the center of the agitator, and a number of stirring paddles are evenly distributed radially with the center of the agitator as the center.

[0009] Further optionally, a second partition net is provided outside the agitator and the aeration pipe, the second partition net including a circular horizontal mesh surface and a vertical mesh surface around the horizontal mesh surface, the bottom of the vertical mesh surface is connected to the fixed frame, the horizontal mesh surface is located above the agitator, and the agitator and the aeration pipe are covered inside the second partition net;

[0010] The mesh size of the vertical mesh surface is smaller than the average particle size of the calcified anaerobic granular sludge.

[0011] Further optionally, the fixed frame is provided with a rotating rod passing through the center of the fixed frame, the fixed frame is not fixedly connected to the bottom of the reaction zone, one end of the rotating rod passes through the side wall of the decalcification and regeneration device, and is connected to an external control motor. When the gate is opened, the rotating rod drives the fixed frame, the second partition, the agitator and the aeration pipe to rotate in the vertical direction, and the sludge in the lower part of the reaction zone is intercepted around the second partition. The second partition rotates so that most of the granular sludge falls preferentially from the gap around the opened second partition, thereby avoiding the impact of a large amount of granular sludge on the agitator and the aeration pipe.

[0012] Optionally, the degassing zone includes an exhaust zone, a guide rail and a mixing zone from top to bottom, the exhaust zone corresponds to the lower part of the reaction zone and surrounds the outer side of the lower part of the reaction zone, and the exhaust port is provided on the side wall of the exhaust zone for discharging the gas after separating from the granular sludge; the guide rail is a circle, and the guide rail is concentrically arranged with the degassing zone, and the top of the stirring rod is connected to the guide rail through a slider, so that the stirring rod can move along the guide rail, thereby stirring the material in the mixing zone;

[0013] The bottom of the mixing zone is conical, and a first discharge port is provided at the bottom of the cone. The first discharge port is connected in parallel with a circulation pipe, and the other end of the circulation pipe is connected to the top of the mixing zone, which can discharge the liquid in the mixing zone and then circulate it back into the mixing zone.

[0014] In a second aspect, the present invention provides a decalcification and regeneration method for the calcified anaerobic granular sludge, comprising the following steps:

[0015] S1: introducing the calcified granular sludge and the decalcifying agent into the reaction zone, turning on the agitator and the aeration device connected to the aeration pipe, so that the calcified granular sludge and the decalcifying agent are fully in contact and react with each other;

[0016] S2: As the calcium carbonate on the surface of the calcified granular sludge and in the micropores is gradually eliminated due to chemical reactions, the particle size of the granular sludge decreases, and the precipitate generated by the reaction passes upward through the first screen and enters the separation zone;

[0017] S3: When the stirring and aeration intensities remain unchanged, decalcification is completed. When the particle detector detects that the particle concentration in the separation zone no longer changes, the pump corresponding to the second discharge port is turned on to discharge the decalcifying agent and sediment in the separation zone into the nutrient pre-storage tank, while stirring and aeration continue.

[0018] S4: opening the gate, stopping the agitator and the aeration device at the same time, and controlling the rotating rod to drive the fixed frame, the second screen, the agitator and the aeration pipe to rotate together, so that a gap is formed between the edge of the second screen and the bottom of the reaction zone, and the decalcified granular sludge and the remaining decalcifying agent pass through the gap and the gate and are discharged into the degassing zone;

[0019] S5: The stirring rod moves in a circular motion along the guide rail to stir the material in the mixing zone, and then all the liquid in the mixing zone is discharged through the first discharge port, and then the discharged liquid is returned to the mixing zone through the circulation pipe. This operation is repeated several times to promote the exhaust of the granular sludge in the mixing zone; after exhaust, the granular sludge is discharged into the culture zone;

[0020] S6: The sewage, activated sludge and materials in the nutrient pre-storage tank are input into the culture area and contacted with the degassed granular sludge, so that anaerobic microorganisms are attached to the surface and micropores of the granular sludge; after the culture is completed, the reactivated granular sludge is discharged back to the anaerobic processor.

[0021] Optionally, in step S1, the decalcifying agent is obtained by dissolving phosphoric acid, sodium tripolyphosphate, sodium lignin sulfonate and sodium pyrophosphate in N,N-dimethylformamide, wherein the mass ratio of phosphoric acid, sodium tripolyphosphate, sodium lignin sulfonate and sodium pyrophosphate is (30-50):(15-35):(5-15):(1-10); the concentration of phosphoric acid in the decalcifying agent is 10-17%.

[0022] Optionally, in step S6, the activated sludge is activated granular sludge, and the amount of sludge added is 12-15 kg VSS / m 3 , the temperature in the culture area is 30-38℃, the pH is 6.8-7.2, and the ratio of COD to N element concentration and P element concentration is (110-250):(5-6):1;

[0023] The COD concentration of the sewage input into the culture area is 2000-5000 mg / L. When the COD removal rate of the water in the culture area reaches 80-90%, it indicates that the granular sludge regeneration culture is completed.

[0024] In step S6, the amount of material in the nutrient pre-storage tank input into the culture area is adjusted according to actual conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of the decalcification and regeneration device for calcified anaerobic granular sludge of Example 1;

[0026] Figure 2 for Figure 1 Stereoscopic diagram (temporary storage tank and circulation pipe omitted).

[0027] In the accompanying drawings, 1- decalcification zone, 2- degassing zone, 3- cultivation zone, 4- aeration pipe, 5- stirrer, 6- gate, 7- guide rail, 8- stirring rod, 9- first discharge port, 10- reaction zone, 11- separation zone, 12- first partition net, 13- second partition net, 14- second discharge port, 15- nutrient pre-storage tank, 16- fixed rack, 17- temporary storage tank, 18- exhaust zone, 19- mixing zone, 20- circulation pipe. DETAILED DESCRIPTION

[0028] Example 1

[0029] The decalcification and regeneration device of the calcified anaerobic granular sludge provided in this embodiment is as follows: Figure 1-Figure 2 As shown, from top to bottom, it includes a decalcification zone 1, a degassing zone 2, and a culture zone 3. The side of the decalcification zone 1 is provided with a drug inlet and a feed inlet, which are used to input a decalcifying agent and calcified anaerobic granular sludge, respectively. The bottom of the decalcification zone 1 is provided with an aeration pipe 4 and a stirrer 5, which are used to promote the contact and reaction between the decalcifying agent and the calcified anaerobic granular sludge. A gate 6 that can be opened and closed is provided below the stirrer 5 and the aeration pipe 4, which is used to discharge the decalcified granular sludge into the degassing zone 2.

[0030] A guide rail 7 and a stirring rod 8 are provided at the top of the degassing zone 2. The stirring rod 8 moves along the guide rail 7 to stir the granular sludge in the degassing zone 2, thereby promoting the removal of bubbles on the surface of the granular sludge and in the micropores. A first discharge port 9 is provided at the bottom of the degassing zone 2 for discharging the degassed granular sludge into the culture zone 3.

[0031] The culture area 3 is provided with a sewage inlet for inputting sewage and activated sludge to culture the degassed granular sludge. The first discharge port is provided with a control valve to control opening and closing.

[0032] The decalcification zone 1 includes a reaction zone 10 at the bottom and a separation zone 11 at the top. A horizontal first partition 12 is provided between the reaction zone 10 and the separation zone 11. A second discharge port 14 is provided on the side wall of the bottom of the separation zone 11. The second discharge port 14 is connected to the nutrient pre-storage tank 15 through a pipeline; a drug inlet and a feed port are provided on the side of the top of the reaction zone 10. The lower part of the reaction zone 10 is a cone with a larger top and a smaller bottom. An agitator 5 and an aeration pipe 4 are provided at the bottom of the cone. The aeration pipe 4 is provided below the agitator 5, and an openable and closable gate 6 is provided below the aeration pipe 4.

[0033] The mesh size of the first screen 12 is smaller than the average particle size of the calcified anaerobic granular sludge, and the calcified anaerobic granular sludge is intercepted in the reaction zone 10 to continue to react with the decalcifying agent. The decalcified granular sludge and the precipitate obtained by the reaction can enter the separation zone 11 under the action of stirring and aeration.

[0034] A horizontal fixing frame 16 is provided below the aeration pipe 4, and the aeration pipe 4 is mounted on the fixing frame 16 and is evenly distributed below the agitator 5; the agitator 5 is arranged horizontally as a whole, and the motor of the agitator 5 can be arranged at the center of the fixing frame 16, or can be arranged above the outside of the decalcification regeneration device. The rotating shaft of the motor is arranged vertically and connected to the center of the agitator 5. Several stirring paddles are evenly distributed radially with the center of the agitator 5 as the center. The cross section of the agitator 5 is circular, and the fixing frame 16 is also circular.

[0035] A second screen 13 is provided outside the agitator 5 and the aeration tube 4. The second screen 13 includes a circular horizontal screen and a vertical screen around the horizontal screen. The bottom of the vertical screen is connected to the fixing frame 16. The horizontal screen is located above the agitator 5, covering the agitator 5 and the aeration tube 4 inside the second screen 13.

[0036] The mesh size of the vertical mesh surface is smaller than the average particle size of the calcified anaerobic granular sludge.

[0037] The top of the separation zone 11 is provided with an air outlet and a cleaning spray pipe. The air outlet is used to discharge excess gas in the decalcification zone 1. The cleaning spray pipe is used to clean the decalcification zone 1 after the decalcified granular sludge is discharged from the reaction zone 10. The cleaning water is discharged into the degassing zone 2 through the gate 6.

[0038] The stirring paddle is plate-shaped and forms an angle of 30° with the horizontal plane to prevent granular sludge from accumulating on the surface of the stirring paddle.

[0039] The decalcification and regeneration device is generally cylindrical, facilitating material flow and contact within each internal zone and avoiding dead zones associated with a square shape. The decalcification agent and calcified anaerobic granular sludge are introduced into the reaction zone 10, with the decalcification agent liquid level reaching the upper portion or top of the separation zone 11. The decalcification agent and calcified anaerobic granular sludge primarily undergo a chemical reaction within the reaction zone 10. The dual agitation of stirring and aeration promotes full contact and reaction between the reactants, removing calcium from the surface and micropores of the granular sludge, reducing the particle size of the granular sludge and generating new chemical precipitates. With the stirring and aeration, the precipitates move upward through the first screen 12 and into the separation zone 11. The gases generated by the decalcification reaction and the bubbles from the aeration not only help occupy the micropores of the granular sludge, preventing newly generated precipitates from occupying the micropores and causing further clogging, but also promote the separation of the decalcified granular sludge from the calcified granular sludge. Furthermore, the bubbles facilitate the adhesion of the newly generated precipitates, promoting the continued floating of the precipitates and their further separation from the decalcified granular sludge.

[0040] The material in reaction zone 10 flows upward under the action of agitation and aeration. Unreacted calcified anaerobic granular sludge is intercepted by first screen 12. Under the influence of subsequent upward flow, the intercepted material flows downward around reaction zone 10, falling along the tapered, inclined wall surface at the bottom of reaction zone 10 to the bottom of reaction zone 10. It is intercepted by the vertical mesh surface of second screen 13 and cannot enter and affect the operation of agitator 5. It can only continue to flow toward the horizontal mesh surface. A gap is left between the outer end of the agitator paddle of agitator 5 and the vertical mesh surface to not affect the rotation of agitator 5. Once the material enters the horizontal mesh surface, it will flow upward under the action of agitation and aeration, and will not fall through the horizontal mesh surface and affect agitator 5. The mesh of the horizontal mesh surface does not affect the output of agitation and aeration.

[0041] The second discharge port 14 is provided with a third screen to prevent a large amount of decalcified granular sludge from being discharged into the nutrient pre-storage tank 15 along with the water and newly generated sediment;

[0042] The outlet of the nutrient pre-storage tank 15 is connected to the culture area 3 via a pipeline for inputting nutrients into the culture area 3;

[0043] A particle detector is installed in the separation zone 11. When the stirring and aeration intensities remain unchanged and the particle concentration in the separation zone 11 remains constant, it indicates that the granular sludge has been decalcified and no new sediment has been generated. At this time, the pump corresponding to the second discharge port 14 is turned on to discharge the water and sediment in the separation zone 11 into the nutrient pre-storage tank 15. The sediment particles generated by the reaction are smaller than the particle size of the decalcified granular sludge.

[0044] The fixed frame 16 is provided with a rotating rod that passes through the center of the fixed frame 16. The fixed frame 16 is not fixedly connected to the bottom of the reaction zone 10. One end of the rotating rod passes through the side wall of the decalcification and regeneration device and is connected to an external control motor. When the gate 6 is opened, the rotating rod drives the fixed frame 16, the second partition screen 13, the agitator 5 and the aeration pipe 4 to rotate in the vertical direction. The sludge in the lower part of the reaction zone 10 is intercepted around the second partition screen 13. The second partition screen 13 rotates, so that most of the granular sludge falls preferentially from the gaps around the opened second partition screen 13, thereby avoiding the impact of a large amount of granular sludge on the agitator 5 and the aeration pipe 4.

[0045] The degassing zone 2 includes, from top to bottom, an exhaust zone 18, a guide rail 7, and a mixing zone 19. The exhaust zone 18 corresponds to the lower portion of the reaction zone 10 and surrounds the outer side of the lower portion of the reaction zone 10. An exhaust port is provided on the sidewall of the exhaust zone 18 for discharging gas separated from the granular sludge. The guide rail 7 is a circle and is concentrically arranged with the degassing zone 2. The top of the stirring rod 8 is connected to the guide rail 7 via a slider, so that the stirring rod 8 can move along the guide rail 7 to stir the material in the mixing zone 19.

[0046] The bottom of the mixing zone 19 is conical, and a first discharge port 9 is provided at the bottom of the cone. The first discharge port 9 is connected in parallel with a circulation pipe 20. The other end of the circulation pipe 20 is connected to the top of the mixing zone 19. The liquid in the mixing zone 19 can be discharged and then circulated back to the interior of the mixing zone 19, so that the granular sludge in the mixing zone 19 is intermittently exposed to the air, thereby bursting the bubbles on the sludge.

[0047] An inclined wall is provided between the exhaust zone 18 and the lower portion of the reaction zone 10 to isolate the exhaust zone 18 from the reaction zone 10 .

[0048] At least one ultrasonic plate is provided on the outer surface of the stirring rod 8 , and the ultrasonic plate is electrically connected to an external ultrasonic control device. The granular sludge in the mixing zone 19 is degassed under the action of ultrasound.

[0049] The circulation pipe 20 is provided with a temporary storage tank 17 for temporarily storing the liquid input by the circulation pipe 20 . After the liquid in the mixing zone 19 is discharged, the liquid in the temporary storage tank 17 is returned to the mixing zone 19 .

[0050] A sewage inlet is provided at the top of the culture area 3 for inputting sewage and activated sludge into the culture area 3, so as to promote the re-attachment of anaerobic microorganisms to the micropores and surfaces of the granular sludge discharged into the culture area 3; a third discharge port is provided at the bottom of the culture area 3 for discharging the cultured anaerobic granular sludge.

[0051] Comparative Example 1

[0052] The decalcification and regeneration device for calcified anaerobic granular sludge in this comparative example is the same as that in Example 1, except that the aeration pipe 4 and the degassing zone 2 are not provided, and the culture zone 3 is directly below the decalcification zone 1. That is, when the gate 6 of the reaction zone 10 is opened, the decalcified granular sludge is discharged into the culture zone 3.

[0053] Comparative Example 2

[0054] The decalcification and regeneration device for calcified anaerobic granular sludge in this comparative example is the same as that in Example 1, except that the degassing zone 2 is not provided, and the cultivation zone 3 is directly below the decalcification zone 1, that is, when the gate 6 of the reaction zone 10 is opened, the decalcified granular sludge is discharged into the cultivation zone 3.

[0055] Example 2

[0056] This embodiment provides a decalcification and regeneration method for calcified anaerobic granular sludge, using the decalcification and regeneration device of Example 1, including the following steps:

[0057] S1: Calcified granular sludge and decalcifying agent are introduced into the reaction zone 10, and the agitator 5 and the aeration device connected to the aeration pipe 4 are turned on to allow the calcified granular sludge and the decalcifying agent to fully contact and react;

[0058] S2: As calcium carbonate on the surface of the calcified granular sludge and in the micropores is gradually eliminated due to chemical reactions, the particle size of the granular sludge decreases, and the precipitate generated by the reaction passes upward through the first screen 12 and enters the separation zone 11;

[0059] S3: When the stirring and aeration intensities remain unchanged, decalcification is completed. When the particle detector detects that the particle concentration in the separation zone 11 no longer changes, the pump corresponding to the second discharge port 14 is turned on to discharge the decalcifying agent and sediment in the separation zone 11 into the nutrient pre-storage tank 15, while stirring and aeration are continued.

[0060] S4: Open the gate 6, stop the agitator 5 and the aeration device at the same time, and control the rotating rod to drive the fixed frame 16, the second screen 13, the agitator 5 and the aeration pipe 4 to rotate together, so that a gap appears between the edge of the second screen 13 and the bottom of the reaction zone 10, and the decalcified granular sludge and the remaining decalcifying agent pass through the gap and the gate 6 and are discharged into the degassing zone 2;

[0061] S5: The stirring rod 8 moves in a circular motion along the guide rail 7 to stir the material in the mixing zone 19, and then all the liquid in the mixing zone 19 is discharged through the first discharge port 9, and then the discharged liquid is returned to the mixing zone 19 through the circulation pipe 20. This operation is repeated three times to promote the exhaust of the granular sludge in the mixing zone 19; after the exhaust, the granular sludge is discharged into the culture zone 3;

[0062] S6: The sewage, activated sludge and the materials in the nutrient pre-storage tank 15 are input into the culture area 3 to contact with the degassed granular sludge, so that anaerobic microorganisms adhere to the surface and micropores of the granular sludge; after the culture is completed, the reactivated granular sludge is discharged back to the anaerobic processor.

[0063] In step S1, the decalcifying agent is obtained by dissolving phosphoric acid, sodium tripolyphosphate, sodium lignin sulfonate and sodium pyrophosphate in N,N-dimethylformamide, wherein the mass ratio of phosphoric acid, sodium tripolyphosphate, sodium lignin sulfonate and sodium pyrophosphate is 30:15:5:1; and the concentration of phosphoric acid in the decalcifying agent is 10%.

[0064] The phosphate anions in the decalcifying agent react with the calcium salts deposited on the surface of the granular sludge, causing the calcium salts to dissolve and form precipitates or chelates, which are then washed into the water body by the water flow. Bubbles adhere to the micropores or surface of the granular sludge, and the bubbles form a barrier between the granular sludge and the precipitate, thereby achieving the purpose of decalcifying the calcified granular sludge.

[0065] In steps S2 and S3, the rotation speed and aeration intensity of agitator 5 are adjusted to ensure a circulating flow of particles within reaction zone 10, preventing the granular sludge from falling onto the horizontal surface of second screen 13. Calcified granular sludge can be carried by the water flow, while decalcified granular sludge and precipitated particles are more easily carried by the water flow into separation zone 11.

[0066] The precipitate and chelate formed by decalcification, as well as the remaining decalcifying agent solution, contain phosphorus, calcium and other elements, which are nutrients required for anaerobic microbial culture. This embodiment uses the nutrient pre-storage tank 15 to collect these materials and reuse them in the culture area 3.

[0067] After step S4, the process also includes the step of cleaning the decalcification zone 1, using a cleaning spray pipe to clean the decalcification zone 1 and each screen, agitator 5, and fixing frame 16, and discharge the residual sludge into the degassing zone 2; then the rotating rod is rotated in the opposite direction to reset the second screen 13 and close the gate 6, so that the next batch of calcified granular sludge can be decalcified in the decalcification zone 1.

[0068] In step S5, when the stirring rod 8 stirs the material in the mixing zone 19, the ultrasonic plate is activated to generate ultrasound to promote the degassing of the granular sludge. The degassing gas moves upward into the exhaust zone 18 and is then discharged from the exhaust port.

[0069] Intermittently drain all the liquid in the mixing zone 19 so that the granular sludge is intermittently exposed to the air. The atmospheric pressure difference is used to cause the bubbles on the granular sludge to burst, thus preparing conditions for subsequent sludge cultivation.

[0070] The degassing time changes according to the air pressure in the exhaust zone 18. When the air pressure is always close to the atmospheric pressure, it means that the degassing is completed. Then, the granular sludge is discharged into the culture zone 3 through the first discharge port 9. The conical bottom of the mixing zone 19 allows the granular sludge and water to be completely discharged; the degassing treatment of the next batch of decalcified granular sludge can be carried out in the degassing zone 2.

[0071] In step S6, the activated sludge is activated granular sludge, and the amount of sludge added is 12kgVSS / m 3 , the temperature in the culture zone 3 is 30-35°C, the pH is 6.8-7.0, and the ratio of COD to N element concentration and P element concentration is 110:5:1;

[0072] The COD concentration of the sewage input into the culture zone 3 is 4000 mg / L. When the COD removal rate of the water in the culture zone 3 reaches 80%, it indicates that the granular sludge regeneration culture is completed.

[0073] In step S6 , during the entire culturing process, the material in the nutrient pre-storage tank 15 is continuously and constantly fed into the culturing area 3 .

[0074] Comparative Example 3

[0075] This comparative example provides a decalcification and regeneration method for calcified anaerobic granular sludge, which is the same as Example 2, except that the decalcification and regeneration device of Comparative Example 1 is used, and accordingly, no aeration is performed in steps S1, S2 and S3, and step S4 is not included, in which the decalcified granular sludge and the remaining decalcifying agent are discharged into the culture area through the gate; and step S5 is not included.

[0076] Comparative Example 4

[0077] This comparative example provides a decalcification and regeneration method for calcified anaerobic granular sludge, which is the same as Example 2, except that the decalcification and regeneration device of Comparative Example 2 is used, and step S4 is not included, in which the decalcified granular sludge and the remaining decalcifying agent are discharged into the culture area through the gate; and step S5 is not included.

[0078] Comparative Example 5

[0079] This comparative example provides a decalcification and regeneration method for calcified anaerobic granular sludge, which is the same as Example 2, except that the decalcification and regeneration device of Example 1 is used, and the material in the nutrient pre-storage tank in step S6 is not input into the culture area.

[0080] Comparative Example 6

[0081] This comparative example provides a decalcification and regeneration method for calcified anaerobic granular sludge, which is the same as Example 2, except that the decalcification and regeneration device of Example 1 is used. In step S5, the stirring rod continues to stir the material in the mixing zone until the exhaust is completed. After the exhaust is completed, the granular sludge is discharged into the culture zone.

[0082] Example 3

[0083] This embodiment provides a decalcification and regeneration method for calcified anaerobic granular sludge, which is the same as that of Example 2, except that the decalcification and regeneration device of Example 1 is used, and the mass ratio of phosphoric acid, sodium tripolyphosphate, sodium lignin sulfonate and sodium pyrophosphate in the decalcifying agent is 50:35:15:1.

[0084] Example 4

[0085] This embodiment provides a decalcification and regeneration method for calcified anaerobic granular sludge, which is the same as that of Example 2, except that the decalcification and regeneration device of Example 1 is used, and the mass ratio of phosphoric acid, sodium tripolyphosphate, sodium lignin sulfonate and sodium pyrophosphate in the decalcifying agent is 29:14:4:1.

[0086] Example 5

[0087] This embodiment provides a decalcification and regeneration method for calcified anaerobic granular sludge, which is the same as that of Example 2, except that the decalcification and regeneration device of Example 1 is used, and the concentration of phosphoric acid in the decalcification agent is 17%.

[0088] Example 6

[0089] This embodiment provides a decalcification and regeneration method for calcified anaerobic granular sludge, which is the same as that of Example 2, except that the decalcification and regeneration device of Example 1 is used and the concentration of phosphoric acid in the decalcification agent is 9%.

[0090] Example 7

[0091] This embodiment provides a decalcification and regeneration method for calcified anaerobic granular sludge, which is the same as that of embodiment 2, except that the decalcification and regeneration device of embodiment 1 is used, and in step S6, the amount of activated granular sludge added is 15 kg VSS / m 3 .

[0092] Example 8

[0093] This embodiment provides a decalcification and regeneration method for calcified anaerobic granular sludge, which is the same as that of embodiment 2, except that the decalcification and regeneration device of embodiment 1 is used, and in step S6, the amount of activated granular sludge added is 11 kg VSS / m 3 .

[0094] The regenerated anaerobic granular sludge obtained in Examples 2-8 and Comparative Examples 3-6 was used for industrial wastewater treatment. The COD of the raw wastewater was 4500 mg / L and the treatment capacity was 50 m3. 3 / h, hydraulic retention time of 44h, anaerobic treatment, conditions are temperature of 30-35℃, pH of 6.8-7.0, and granular sludge concentration of 5000mg / L.

[0095] Table 1 Comparison of granular sludge regeneration effects between the embodiment and the comparative example

[0096]

[0097] As can be seen from the above table, the decalcification and regeneration device and method for calcified anaerobic granular sludge provided by the present invention can achieve a good decalcification effect through chemical reaction combined with stirring and aeration. The decalcified granular sludge is occupied by bubbles, avoiding the influence of sediment on the granular sludge. The method of intermittently exposing the granular sludge in the degassing zone is then used to promote the removal of bubbles, providing good conditions for cultivating anaerobic microorganisms, thereby obtaining granular sludge with good decalcification and regeneration.

Claims

1. A decalcification and regeneration device for calcified anaerobic granular sludge, characterized in that: From top to bottom, it includes a decalcification zone, a degassing zone, and a culture zone. The side of the decalcification zone is provided with a drug inlet and a feed inlet for inputting decalcification agent and calcified anaerobic granular sludge respectively. The bottom of the decalcification zone is provided with an aeration pipe and a stirrer for promoting contact and reaction between the decalcification agent and calcified anaerobic granular sludge. An openable and closable gate is provided below the stirrer and aeration pipe for discharging the decalcified granular sludge into the degassing zone. The upper part of the degassing zone is provided with a guide rail and a stirring rod. The stirring rod moves along the guide rail to stir the granular sludge in the degassing zone, promoting the removal of bubbles on the surface of the granular sludge and in the micropores. The bottom of the degassing zone is provided with a first discharge port for discharging the degassed granular sludge into the culture zone. The culture area is equipped with a sewage inlet for inputting sewage and activated sludge to cultivate deaerated granular sludge; The decalcification zone includes a reaction zone at the bottom and a separation zone at the top. A first horizontal screen is provided between the reaction zone and the separation zone. A second discharge port is provided on the side wall of the bottom of the separation zone. The second discharge port is connected to the nutrient pre-storage tank through a pipeline. A third screen is provided at the second discharge port. A drug inlet and a feed inlet are provided on the side of the top of the reaction zone. The lower part of the reaction zone is conical with a larger upper portion and a smaller lower portion. An agitator and an aeration pipe are provided at the bottom of the cone. The aeration pipe is provided below the agitator. An openable and closable gate is provided below the aeration pipe. The mesh size of the first screen is smaller than the average particle size of the calcified anaerobic granular sludge, so that the calcified anaerobic granular sludge is intercepted in the reaction zone and continues to react with the decalcifying agent. The decalcified granular sludge and the precipitate obtained by the reaction can enter the separation zone under the action of stirring and aeration; The degassing zone includes an exhaust zone, a guide rail, and a mixing zone from top to bottom. The exhaust zone corresponds to the lower part of the reaction zone and surrounds the outer side of the lower part of the reaction zone. An exhaust port is provided on the side wall of the exhaust zone for discharging gas after separation from the granular sludge. The guide rail is a circle and is concentrically arranged with the degassing zone. The top of the stirring rod is connected to the guide rail via a slider, so that the stirring rod can move along the guide rail to stir the material in the mixing zone. The bottom of the mixing zone is conical, and a first discharge port is provided at the bottom of the cone. The first discharge port is connected in parallel with a circulation pipe, and the other end of the circulation pipe is connected to the top of the mixing zone, which can discharge the liquid in the mixing zone and then circulate it back into the mixing zone.

2. The decalcification and regeneration device for calcified anaerobic granular sludge according to claim 1, characterized in that: A horizontal fixing frame is provided below the aeration pipe, and the aeration pipe is installed on the fixing frame and is evenly distributed below the agitator; the agitator is set horizontally as a whole, the rotating shaft of the agitator motor is set vertically and connected to the center of the agitator, and several agitating paddles are evenly distributed radially with the center of the agitator as the center.

3. The decalcification and regeneration device for calcified anaerobic granular sludge according to claim 2, characterized in that: A second partition net is provided outside the agitator and the aeration pipe. The second partition net includes a circular horizontal mesh surface and a vertical mesh surface around the horizontal mesh surface. The bottom of the vertical mesh surface is connected to the fixed frame. The horizontal mesh surface is located above the agitator. The agitator and the aeration pipe are covered inside the second partition net. The mesh size of the vertical mesh surface is smaller than the average particle size of the calcified anaerobic granular sludge.

4. The decalcification and regeneration device for calcified anaerobic granular sludge according to claim 3, characterized in that: The fixed frame is provided with a rotating rod passing through the center of the fixed frame. The fixed frame is not fixedly connected to the bottom of the reaction zone. One end of the rotating rod passes through the side wall of the decalcification and regeneration device and is connected to an external control motor. When the gate is opened, the rotating rod drives the fixed frame, the second partition screen, the agitator and the aeration pipe to rotate in the vertical direction. The sludge in the lower part of the reaction zone is intercepted around the second partition screen. The second partition screen rotates, so that most of the granular sludge falls preferentially from the gap around the opened second partition screen, thereby avoiding the impact of a large amount of granular sludge falling on the agitator and the aeration pipe.

5. A decalcification and regeneration method for calcified anaerobic granular sludge, characterized in that: The decalcification and regeneration device for calcified anaerobic granular sludge according to claim 4 comprises the following steps: S1: introducing the calcified granular sludge and the decalcifying agent into the reaction zone, turning on the agitator and the aeration device connected to the aeration pipe, so that the calcified granular sludge and the decalcifying agent are fully in contact and react with each other; S2: As the calcium carbonate on the surface of the calcified granular sludge and in the micropores is gradually eliminated due to chemical reactions, the particle size of the granular sludge decreases, and the precipitate generated by the reaction passes upward through the first screen and enters the separation zone; S3: When the stirring and aeration intensities remain unchanged, decalcification is completed. When the particle detector detects that the particle concentration in the separation zone no longer changes, the pump corresponding to the second discharge port is turned on to discharge the decalcifying agent and sediment in the separation zone into the nutrient pre-storage tank, while stirring and aeration continue. S4: opening the gate, stopping the agitator and the aeration device at the same time, and controlling the rotating rod to drive the fixed frame, the second screen, the agitator and the aeration pipe to rotate together, so that a gap is formed between the edge of the second screen and the bottom of the reaction zone, and the decalcified granular sludge and the remaining decalcifying agent pass through the gap and the gate and are discharged into the degassing zone; S5: The stirring rod moves in a circular motion along the guide rail to stir the material in the mixing zone, and then all the liquid in the mixing zone is discharged through the first discharge port, and then the discharged liquid is returned to the mixing zone through the circulation pipe. This operation is repeated several times to promote the exhaust of the granular sludge in the mixing zone; after exhaust, the granular sludge is discharged into the culture zone; S6: Sewage and activated sludge are input into the culture area to contact with the degassed granular sludge, so that anaerobic microorganisms are attached to the surface and micropores of the granular sludge; after the culture is completed, the reactivated granular sludge is discharged back to the anaerobic processor.

6. The decalcification and regeneration method of calcified anaerobic granular sludge according to claim 5, characterized in that: In step S1, the decalcifying agent is obtained by dissolving phosphoric acid, sodium tripolyphosphate, sodium lignin sulfonate and sodium pyrophosphate in N,N-dimethylformamide, wherein the mass ratio of phosphoric acid, sodium tripolyphosphate, sodium lignin sulfonate and sodium pyrophosphate is (30-50):(15-35):(5-15):(1-10); the concentration of phosphoric acid in the decalcifying agent is 10-17%.

7. The decalcification and regeneration method of calcified anaerobic granular sludge according to claim 5, characterized in that: In step S6, the activated sludge is activated anaerobic granular sludge, the temperature in the culture zone is 30-38° C., the pH is 6.8-7.2, and the ratio of COD to N element concentration and P element concentration is (110-250):(5-6):1; The COD concentration of the sewage input into the culture area is 2000-5000 mg / L. When the COD removal rate of the water in the culture area reaches 80-90%, it indicates that the granular sludge regeneration culture is completed.

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