CN208055167U - Granule sludge original position flotation calcium-removing reactor - Google Patents

Abstract

The utility model discloses a granular sludge in-situ flotation decalcification reactor, which belongs to the field of sewage or sludge treatment. The reactor includes a reactor main body, a decalcification liquid feeding system, and a biogas stirring system. The main body of the reactor is equipped with a distribution area, a decalcification area, and a three-phase separation area; the distribution area is equipped with a water distribution pipe, a water inlet pipe, a lower circulating water pipe, a gas distribution pipe, and a gas delivery pipe; the decalcification area is equipped with a vertical partition, a left granular sludge bed, The right granular sludge bed; the three-phase separation area is equipped with a three-phase separator, a sedimentation chamber, a gas collection chamber, an overflow weir, and an upper circulating water pipe. The decalcification liquid feeding system is equipped with a decalcification liquid storage tank, a decalcification liquid delivery pump, a decalcification liquid delivery pipe and a decalcification liquid distribution pipe. The biogas mixing system is equipped with a biogas storage tank, a biogas booster pump, a biogas booster tank, a biogas delivery pipe and a biogas distribution pipe. The utility model can realize the conversion of organic matters and the in-situ decalcification of granular sludge in different periods of time.

Description

Granular sludge in-situ flotation decalcification reactor

technical field

The utility model belongs to the field of sewage or sludge treatment, in particular to an in-situ flotation decalcification reactor for granular sludge.

Background technique

After more than a century of research and development, anaerobic bioreactors have developed to the third generation of reactors represented by anaerobic granular sludge expanded bed reactors and internal circulation reactors. Anaerobic bioreactors are widely used in industrial and agricultural organic wastewater treatment due to their unique high efficiency and economic advantages. However, when dealing with industrial organic wastewater such as petrochemical, papermaking, printing and dyeing, the challenge of high calcium is encountered. Ca ²⁺ in wastewater combines with CO ₂ produced by microbial metabolism to form CaCO ₃ deposited on the surface and inside of granular sludge, which affects the mass transfer of granular sludge, reduces the efficiency of the reactor, and increases the burden of residual sludge treatment .

In terms of engineering, the method of replacing granular sludge is currently used to solve the problem of calcification. Although this method is effective, it is expensive, and the reactor needs to be restarted, which affects daily wastewater treatment. If the granular sludge is removed from the reactor for ex-situ treatment, the operation process is more complicated, and it will also cause damage to the granular sludge. Therefore, it is of great practical significance to develop in-situ decalcification technology of granular sludge.

Since organic acids (such as acetic acid) and inorganic acids (such as sulfuric acid) can dissolve calcium carbonate, they can be used for decalcification of calcified granular sludge.

CaCO ₃ +2HAc→Ca(Ac) ₂ +H ₂ O+CO ₂ ↑

CaCO ₃ +H ₂ SO ₄ →CaSO ₄ +H ₂ O+CO ₂ ↑

The density of granular sludge becomes larger after calcification. According to the Stokes formula, its sedimentation velocity is higher than that of ordinary granular sludge. There is a difference in the critical loss flow velocity of the two sludges. The rising velocity of the controlled water flow is between the two flow velocities. Separation of mud particles and decalcified granular sludge.

where v _s is the sedimentation rate of a single granular sludge, d _p is the diameter of the granular sludge, _ρ is the density of the granular sludge, ρ is the density of the solution, and μ is the viscosity of the solution.

The utility model integrates the transformation of organic matter and the decalcification of calcified sludge, can realize in-situ decalcification of sludge, and reduces the consumption of manpower, material resources and financial resources and sludge damage caused by ectopic operations. Making full use of the organic matter conversion products of the reactor itself, the operation process is simple and the material consumption is low.

Contents of the invention

The purpose of the utility model is to overcome the deficiencies of the prior art and provide an in-situ decalcification reactor for granular sludge, especially an in-situ flotation decalcification reactor for granular sludge.

The concrete technical scheme that the utility model adopts is as follows:

Granular sludge in-situ flotation decalcification reactor, which includes a reactor body, a decalcification liquid feeding system, and a biogas stirring system;

The main body of the reactor is sequentially provided with a distribution area, a decalcification area, and a three-phase separation area from bottom to top; a vertical partition is arranged in the decalcification area, and the vertical partition divides the decalcification area into symmetrical left and right sides. The granular sludge bed and the right granular sludge bed; the bottom of the vertical partition extends to the distribution area; the distribution area is laid with a water distribution pipe and an air distribution pipe above the water distribution pipe, and both the water distribution pipe and the air distribution pipe have two sets of independent The modules are distributed in a mirror image with the vertical partition as the central plane. Each side of the vertical partition has a set of water distribution pipe modules and a set of air distribution pipe modules, which are respectively located in the left granular sludge bed and the right granular sludge bed. Directly below. Each group of water distribution pipe modules is connected to a water inlet pipe, and each group of air distribution pipe modules is connected to an air pipe; the water inlet pipe is connected to the lower circulating water pipe; The top of the zone is connected, and a three-phase separator is installed in the three-phase separation zone, and the three-phase separator is located between the upper edge of the lower expansion section and the lower edge of the gas collection chamber; the three-phase separator includes an inverted funnel, an upflow tube and a downflow tube , the upper edge of the inverted funnel is connected to the lower edge of the upflow tube, and the downflow tube and the upflow tube are concentric cylinders; the gas collection chamber is located at the top of the three-phase separation area; the outer wall of the three-phase separator and the inner wall of the three-phase separation area are clamped to form a ring In the sedimentation chamber, the overflow weir is located on the wall of the sedimentation chamber; one end of the upper circulating water pipe extends into the three-phase separation zone and communicates with the inner cavity of the downflow pipe, and the other end communicates with the lower circulating water pipe;

The decalcification liquid feeding system is provided with a decalcification liquid storage tank, a decalcification liquid delivery pump, and a decalcification liquid delivery pipe. The decalcification liquid storage tank is connected to the water inlet pipe through the decalcification liquid delivery pipe, and the decalcification liquid The delivery pipe is equipped with a decalcification liquid delivery pump;

The biogas mixing system is provided with a biogas storage tank, which is connected to the top of the gas collection chamber through a pipeline, and the biogas storage tank is also connected to the biogas booster tank and the gas transmission pipe in turn through the biogas delivery pipe, and the biogas delivery pipe There is a biogas booster pump on it.

Based on the above solutions, the present invention can also provide the following multiple preferred modes.

The main body of the reactor is in the shape of a three-stage cylinder, and the diameters of the distribution area and the decalcification area are the same, and the ratio of the diameter of the largest section of the two areas to the three-phase separation area is 1:1.5; , The height ratio of the three-phase separation zone is 1:10-12:2.5-3.

The water distribution pipe modules are all in the form of a half-moon ring, and the straight sections of the two groups of water distribution pipe modules are arranged in parallel close to the vertical partition. Each branch road is provided with a control valve; the air distribution pipe module is also in a half-moon ring shape, and the straight sections of the two groups of air distribution pipe modules are arranged in parallel close to the vertical partition, and the air transmission pipe is divided into two paths and passes through the side of the distribution area respectively The wall is connected with two sets of air distribution pipe modules, and each branch is also provided with a control valve.

The upper edge of the vertical partition is at the same height as the lower edge of the three-phase separation area, the lower edge of the vertical partition extends into the distribution area by 10-30 mm, and the vertical distance between the lower edge of the vertical partition and the bottom surface of the distribution area is 40-60 mm .

The lower edge of the inverted funnel of the three-phase separator is at the same height as the upper edge of the expansion section, and the ratio of the area of the lower edge of the inverted funnel to the area of the three-phase separation zone at the same height is 1:2.25; the upper edge of the riser tube 30-50mm lower than the liquid level; the upper edge of the downflow pipe is 20-30mm higher than the liquid surface, and the lower edge of the downflow pipe is 20-30mm higher than the upper edge of the inverted funnel.

The vertical distance between the plane where the water distribution pipe is located and the bottom surface of the distribution area is 30-50 mm, and the vertical distance between the plane where the air distribution pipe is located and the bottom surface of the distribution area is 50-80 mm.

The volume ratio of the decalcification liquid storage tank to the reactor main body is 1:2-3.

The volume ratio of the reactor body to the biogas booster tank is 1:0.3-0.5.

Compared with the prior art, the utility model has the following beneficial effects:

1) The special structure of the separated reaction zone and the operation specialization of aeration and stirring are adopted to realize the internal circulation of the decalcification solution, and the difference in the density of the granular sludge before and after decalcification is used to sort the calcified sludge, so as to reduce the impact of the decalcification solution on the granular sludge damage. 2) Acetic acid formed by anaerobic fermentation of acetogenic bacteria or sulfuric acid produced by sulfuric bacteria can be used as the decalcification solution, and the cost is low. 3) The gas required for decalcification is produced by the conversion of organic matter, without additional gas supply, which can avoid the poisoning of oxygen to anaerobic granular sludge.

Description of drawings

Fig. 1 is the schematic diagram of the front structure of the granular sludge in-situ flotation decalcification reactor;

Fig. 2 is a three-dimensional structural schematic diagram of a granular sludge in-situ flotation decalcification reactor;

Fig. 3 is the front (a), side (b) structural representation of reactor main body;

Fig. 4 is a longitudinal sectional view (a) and a top view (b) of the distribution area.

Reference signs in the figure: reactor main body I, decalcification liquid feeding system II, biogas stirring system III, distribution area I-1, decalcification area I-2, three-phase separation area I-3, water distribution pipe I-1 -1-1, water inlet pipe I-1-1-2, gas distribution pipe I-1-2-1, gas delivery pipe I-1-2-2, vertical partition I-2-1, left granular sludge bed I-2-2, right granular sludge bed I-2-3, three-phase separator I-3-1, sedimentation chamber I-3-2, gas collection chamber I-3-3, overflow weir I-3 -4. Upper circulation pipe I-3-5, lower extension section I-3-6, inverted funnel I-3-1-1, upflow pipe I-3-1-2, downflow pipe I-3-1 -3. Decalcification solution storage tank II-1, decalcification solution delivery pump II-2, decalcification solution delivery pipe II-3, biogas storage tank III-1, biogas booster pump III-2, biogas booster tank III -3. Biogas delivery pipe III-4.

Detailed ways

The utility model will be further elaborated and illustrated below in conjunction with the accompanying drawings and specific embodiments. The technical features of each embodiment in the utility model can be combined correspondingly on the premise that there is no mutual conflict.

As shown in Fig. 1 , an in-situ flotation decalcification reactor for granular sludge in this embodiment mainly includes three parts: a reactor main body I, a decalcification liquid feeding system II, and a biogas stirring system III. Reactor body I is used as the core area for anaerobic treatment of wastewater, and the biogas generated by the anaerobic reaction is stored in the tank of biogas stirring system III, which can re-pump the biogas into the tank during the flotation decalcification stage The main body of the reactor is I, so no additional gas supply is needed, and because the oxygen content in the biogas is low, the poisoning of oxygen to anaerobic granular sludge can be avoided. In this embodiment, the decalcification liquid feeding system II plays multiple functions at the same time, and needs to pump clean water, waste water to be treated or decalcification liquid into the reactor according to the process requirements.

The structure of the granular sludge in-situ flotation decalcification reactor is introduced in detail below.

As shown in Figures 1 to 4, the reactor main body I is in the shape of a three-stage cylinder, and the reactor main body I is sequentially provided with a distribution area I-1, a decalcification area I-2, and a three-phase separation area I-3. . The decalcification zone I-2 is provided with a vertical partition I-2-1, and the vertical partition I-2-1 divides the decalcification zone I-2 into left and right granular sludge beds I- 2-2 and right granular sludge bed I-2-3. The left granular sludge bed I-2-2 and the right granular sludge bed I-2-3 are only connected at the top and bottom, and the rest of the middle positions are sealed and isolated. The bottom of the vertical partition I-2-1 extends into the distribution area I-1. In order to realize the functions of water distribution and air distribution, a water distribution pipe I-1-1-1 and an air distribution pipe I-1-2-1 above the water distribution pipe I-1-1-1 are laid in the distribution area I-1. As shown in Figure 4, both the water distribution pipe I-1-1-1 and the air distribution pipe I-1-2-1 have two sets of independent modules, and are distributed in a mirror image with the vertical partition I-2-1 as the central plane. Each side of the vertical partition I-2-1 has one and only one set of water distribution pipe I-1-1-1 modules and one set of air distribution pipe I-1-2-1 modules. Each group of water distribution pipe I-1-1-1 modules is connected to a water inlet pipe I-1-1-2, and each group of air distribution pipe I-1-2-1 modules is connected to an air delivery pipe I-1-2-2. Since each group of models needs to be controlled independently, the water inlet pipe I-1-1-2 or air pipe I-1-2-2 on each group of modules needs to be controlled independently, and different pipes can be used, or the same pipe can be used In the way that the main road is divided into two branches, but the control valves that control the on-off of the pipelines need to be installed on the branches. In this embodiment, in order to distribute water evenly, the modules of the water distribution pipe I-1-1-1 are in a half-moon ring shape, and the straight sections of the two sets of water distribution pipe I-1-1-1 modules are all close to the vertical partition I-2 -1 is set in parallel, the water inlet pipe I-1-1-2 is divided into two roads and passes through the side wall of the distribution area I-1 to connect two sets of water distribution pipe I-1-1-1 modules, and each branch road is equipped with The solenoid valve is used for control; similarly, the air distribution pipe I-1-2-1 module is also in the shape of a half-moon ring, and the straight sections of the two groups of air distribution pipe I-1-2-1 modules are close to the vertical partition I-2-1 and parallel Setting, the gas transmission pipe I-1-2-2 is divided into two paths and passes through the side wall of the distribution area I-1 to connect to two groups of gas distribution pipe I-1-2-1 modules, and each branch road is also equipped with a control valve . The opening directions on the air distribution pipe I-1-2-1 and the water distribution pipe I-1-1-1 are all downward.

The lower part of the three-phase separation zone I-3 is connected to the top of the decalcification zone I-2 through the bell-shaped lower extension section I-3-6, and the three-phase separation zone I-3 is provided with a three-phase separator I-3- 1. The three-phase separator I-3-1 is arranged between the upper edge of the lower extension section I-3-6 and the lower edge of the gas collection chamber I-3-3. Three-phase separator I-3-1 comprises inverted funnel I-3-1-1, riser pipe I-3-1-2 and downflow pipe I-3-1-3, inverted funnel I-3-1- 1 The upper edge is airtightly connected with the lower edge of the riser tube I-3-1-2, and the downflow tube I-3-1-3 and the riser tube I-3-1-2 form a concentric cylinder and are clamped between the two The bottom of the annular space communicates with the precipitation chamber I-3-2. The gas collection chamber I-3-3 is located at the top of the three-phase separation zone I-3, and communicates with the top exhaust port of the three-phase separator I-3-1. The outer wall of the three-phase separator I-3-1 is sandwiched by the inner wall of the three-phase separation zone I-3 to form an annular sedimentation chamber I-3-2. The overflow weir I-3-4 is located on the wall of the sedimentation chamber I-3-2, and the wastewater treated by the reactor can be discharged through the overflow weir I-3-4. One end of the upper circulating water pipe I-3-5 extends into the three-phase separation zone I-3 and communicates with the inner cavity of the downflow pipe I-3-1-3, and the other end communicates with the lower circulating water pipe I-1-1-3. The other end of the circulating water pipe I-1-1-3 is connected to the water inlet pipe I-1-1-2.

The mixed liquid in the downflow pipe I-3-1-3 can enter the distribution area I through the upper circulating water pipe I-3-5, the lower circulating water pipe I-1-1-3, and the water inlet pipe I-1-1-2 in turn -1. Of course, in order to better realize backflow, a circulating pump can be further arranged on the upper circulating water pipe I-3-5 or the lower circulating water pipe I-1-1-3.

Decalcification liquid feeding system II is equipped with decalcification liquid storage tank II-1, decalcification liquid delivery pump II-2, decalcification liquid delivery pipe II-3, and decalcification liquid storage tank II-1 is transported through decalcification liquid The pipe II-3 is connected to the water inlet pipe I-1-1-2, and the decalcification liquid delivery pump II-2 is arranged on the decalcification liquid delivery pipe II-3. The decalcification liquid storage tank II-1 can be added with decalcification liquid, clean water or waste water to be treated according to the process requirements.

The biogas mixing system III is equipped with a biogas storage tank III-1, which is connected to the top of the gas collection chamber I-3-3 through a pipeline, and the biogas storage tank III-1 is also connected through a biogas delivery pipe III- 4 Connect the biogas booster tank III-3 and the gas pipeline I-1-2-2 in sequence, and the biogas booster pump III-2 is installed on the biogas pipeline III-4.

In the utility model, since the two sides of the vertical partition I-2-1 are respectively provided with independently controlled water distribution pipe I-1-1-1 modules and air distribution pipe I-1-2-1 modules, it is possible to adjust each The working state of the module controls the circulation state of the internal mixed liquid. If the water distribution pipe I-1-1-1 module and the air distribution pipe I-1-2-1 module on the left work, the water distribution pipe I-1-1-1 module and the air distribution pipe I-1-2-1 module on the right are closed , then driven by the circulating pump and the pressurized biogas pumped in from the gas distribution pipe I-1-2-1, the mixed liquid can rise along the left granular sludge bed I-2-2 and pass through the three-phase separation zone I-3 After the extension section in the lower part, it descends along the right granular sludge bed I-2-3, and then returns to the left granular sludge bed I-2-2 through the distribution area I-1 to realize the circulation of the mixed liquid. The pumped gas carries the sludge particles at the lower extension section I-3-6 due to the expansion of the radius and the slowing down of the flow rate, causing the sludge particles to sink, so the gas carries the mixed solution into the inverted funnel I-3-1-1 and the liter Flow pipe I-3-1-2, the final gas is re-collected to the biogas storage tank III-1 through the gas collection chamber I-3-3, and the mixed liquid enters the downflow pipe I-3-1-3 and returns to Distribution area I-1.

In the present embodiment, the specific parameters of each part in the reactor can be selected as follows:

The vertical distance between the plane where the water distribution pipe I-1-1-1 is located and the bottom of the distribution area is 30-50mm, and the vertical distance between the plane where the air distribution pipe I-1-2-1 is located and the bottom surface of the distribution area is 50-80mm. In the main body of the reactor I, the distribution area I-1 and the decalcification area I-2 have the same diameter, and the ratio of the diameter of the largest section of the two areas to the three-phase separation area I-3 is 1:1.5; the distribution area I-1, The height ratio of the decalcification zone I-2 and the three-phase separation zone I-3 is 1:10-12:2.5-3. The volume ratio of the decalcification liquid storage tank II-1 to the reactor main body I is 1:2~3. The volume ratio of the reactor body I to the biogas booster tank III-3 is 1:0.3-0.5. The upper edge of the vertical partition I-2-1 is at the same height as the lower edge of the three-phase separation area, the lower edge of the vertical partition I-2-1 extends into the distribution area by 10-30mm, and the lower edge of the vertical partition I-2-1 The vertical distance along the bottom surface of distribution area I-1 is 40-60mm. The lower edge of the inverted funnel I-3-1-1 of the three-phase separator I-3-1 is equal to the upper edge of the extension section I-3-6, and the area of the lower edge of the inverted funnel I-3-1-1 is the same as The area ratio of the three-phase separation zone I-3 at the height is 1:2.25; The edge is 20-30mm higher than the liquid surface, and the lower edge of the downflow pipe I-3-1-3 is 20-30mm higher than the upper edge of the inverted funnel I-3-1-1. In actual use, various parameters and proportions can be adjusted according to process requirements. In addition, in order to facilitate control, corresponding control valves can be set on each air pipe or water pipe.

Based on the above reactor, this embodiment also provides a method for in-situ flotation decalcification of granular sludge. After the reactor body I runs the anaerobic treatment process for a certain period of time, a large amount of biogas produced in the anaerobic process is stored in the biogas storage tank III-1, and the Ca ²⁺ in the wastewater combines with the CO ₂ produced by microbial metabolism to form CaCO ₃ It is deposited on the surface and inside of the granular sludge, which affects the mass transfer of the granular sludge and reduces the efficiency of the reactor. Therefore, it is necessary to suspend the anaerobic process and carry out in-situ flotation decalcification of granular sludge. The decalcification process is divided into four stages in turn:

1) Inflating and stirring stage: booster pump III-2 pumps biogas from biogas storage tank III-1 to booster tank III-3 for pressurization, and pressurized biogas passes through biogas delivery pipe III-4 and gas delivery pipe I-1- After 2-2, it enters two groups of air distribution pipe I-1-2-1 modules, and is evenly distributed in the distribution area I-1. The bubbles rise up and stir the sludge bed to relieve the calcified sludge agglomeration.

2) Soaking and decalcification stage: The decalcification liquid in the decalcification liquid storage tank II-1 is delivered to the water inlet pipe I-1-1-2 and two sets of water distribution pipes I-1-2 by the decalcification liquid delivery pump II-2 1-1 module, gradually replace the mixed liquor in the granular sludge bed. The decalcification solution can be selected according to needs, and acetic acid formed by anaerobic fermentation of acetogenic bacteria or sulfuric acid produced by sulfuric bacteria can be used. After the replacement is completed, stop adding the decalcification solution, and soak the granular sludge in the decalcification solution to dissolve the calcium carbonate on the surface and inside of the granular sludge.

3) Circular flotation stage: the pressurized biogas enters a group of gas distribution pipe I-1-2-1 modules through biogas delivery pipe III-4 and gas delivery pipe I-1-2-2, and closes the other group of gas distribution pipes I-1-2-1 module; then the liquid in the downflow pipe I-3-1-3 in the three-phase separation zone I-3 is injected into the air distribution pipe I-1-2 in an open state with a certain reflux ratio The -1 module is located in the water distribution pipe I-1-1-1 module on the same side of the vertical partition I-2-1. Therefore, on one side of the vertical partition I-2-1, there is aeration and backflow, so the mixed liquid is driven by the biogas to surround the vertical partition between the distribution area, the decalcification area and the three-phase separation area. Partition I-2-1 forms an internal circulation, and due to the low density of the decalcified granular sludge, the decalcified granular sludge floats up and accumulates on the upper part of the sludge bed under the action of water flow. After a certain period of time, switch the opening status of the two groups of air distribution pipe I-1-2-1 modules and water distribution pipe I-1-1-1 modules, that is, the originally opened water distribution pipe I-1-1-1 module and air distribution pipe I- The 1-2-1 module is closed, and the other group of water distribution pipe I-1-1-1 module and air distribution pipe I-1-2-1 module are opened to change the water distribution side and the gas distribution side to make the mixed liquid circulate in the opposite direction. After repeating the conversion process several times, the decalcification and flotation of the calcified granular sludge are completed.

4) Cleaning stage: pump clean water into the distribution area I-1, wash the granular sludge bed, and remove the residual decalcification solution.

Finally, the wastewater to be treated is re-pumped to start the anaerobic process of the reactor.

In the above process, the pumping process of clean water or waste water to be treated can be realized by the decalcification liquid feeding system (II). The residence time and process parameters of each process stage can be determined according to the debugging results.

The utility model can realize the conversion of organic matters and in-situ decalcification of granular sludge in different time periods; when decalcifying, stop water intake, provide pressurized biogas and decalcification liquid, and realize decalcification of granular sludge in the internal circulation of decalcification liquid; After decalcification, stop adding decalcification solution and pressurized biogas, resume water intake, and use organic matter to generate biogas; biogas production and sludge decalcification are integrated, the device structure is simple, and the operation is convenient.

The above-mentioned embodiment is only a preferred solution of the present utility model, but it is not intended to limit the present utility model. Various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the present invention. Therefore, all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present utility model.

Claims (8)

1. A granular sludge in-situ flotation decalcification reactor, characterized in that it comprises a reactor main body (I), a decalcification liquid feeding system (II), and a biogas stirring system (III); Described reactor main body (I) is provided with distribution zone (I-1), decalcification zone (I-2), three-phase separation zone (I-3) successively from bottom to top; Described decalcification zone (I- 2) is provided with a vertical partition (I-2-1), and the vertical partition (I-2-1) divides the decalcification area (I-2) into left and right granular sludge beds (I- 2-2) and the right granular sludge bed (I-2-3); the bottom of the vertical partition (I-2-1) extends to the distribution area (I-1); the distribution area (I-1) The water distribution pipe (I-1-1-1) and the air distribution pipe (I-1-2-1) located above the water distribution pipe (I-1-1-1) are laid in the middle, and the water distribution pipe (I-1-1 -1) and the air distribution pipe (I-1-2-1) have two sets of independent modules, and the vertical partition (I-2-1) -1) Each side has a set of water distribution pipe (I-1-1-1) modules and a set of air distribution pipe (I-1-2-1) modules; each set of water distribution pipes (I-1-1-1) The modules are connected to the water inlet pipe (I-1-1-2), and each group of air distribution pipe (I-1-2-1) modules are connected to the air delivery pipe (I-1-2-2); the water inlet pipe (I-1-2-1) 1-1-2) Connected to the lower circulating water pipe (I-1-1-3); the lower part of the three-phase separation zone (I-3) passes through the bell-shaped lower expansion section (I-3-6) Connected to the top of the decalcification zone (I-2), a three-phase separator (I-3-1) is set in the three-phase separation zone (I-3), and the three-phase separator (I-3-1) is located in the lower extension section Between the upper edge of (I-3-6) and the lower edge of the gas collection chamber (I-3-3); the three-phase separator (I-3-1) includes an inverted funnel (I-3-1-1), Riser (I-3-1-2) and downcomer (I-3-1-3), the upper edge of the inverted funnel (I-3-1-1) and the riser (I-3-1- 2) The lower edge is connected, and the downflow pipe (I-3-1-3) and the upflow pipe (I-3-1-2) are concentric tubes; the gas collection chamber (I-3-3) is located in the three-phase separation area (I-3) top; the outer wall of the three-phase separator (I-3-1) and the inner wall of the three-phase separation zone (I-3) are clamped to form an annular settling chamber (I-3-2), and the overflow weir (I-3) -3-4) is located on the wall of the sedimentation chamber (I-3-2); one end of the upper circulating water pipe (I-3-5) extends into the three-phase separation zone (I-3) and the downflow pipe (I-3-1 -3) The inner cavity is connected, and the other end is connected with the lower circulating water pipe (I-1-1-3); The decalcification liquid feeding system (II) is provided with a decalcification liquid storage tank (II-1), a decalcification liquid delivery pump (II-2), a decalcification liquid delivery pipe (II-3), a decalcification liquid The liquid storage tank (II-1) is connected to the water inlet pipe (I-1-1-2) through the decalcification solution delivery pipe (II-3), and the decalcification solution delivery pipe (II-3) is provided with decalcification solution Delivery pump (II-2); The biogas mixing system (III) is provided with a biogas storage tank (III-1), and the biogas storage tank (III-1) is connected to the top of the gas collection chamber (I-3-3) through a pipeline. The tank (III-1) is also sequentially connected to the biogas booster tank (III-3) and the gas pipeline (I-1-2-2) through the biogas delivery pipe (III-4), and the biogas delivery pipe (III-4) Equipped with a biogas booster pump (III-2). 2. The in-situ flotation decalcification reactor for granular sludge as claimed in claim 1 is characterized in that, the reactor main body (I) is a three-stage cylindrical shape, and the distribution area (I-1) The diameter of the decalcification zone (I-2) is the same, and the ratio of the diameter of the largest section of the two zones to the three-phase separation zone (I-3) is 1:1.5; the distribution zone (I-1), the decalcification zone (I-3) -2) The height ratio of the three-phase separation zone (I-3) is 1:10-12:2.5-3. 3. granular sludge in-situ flotation decalcification reactor as claimed in claim 1, is characterized in that, described water distribution pipe (I-1-1-1) module is half moon ring, two groups of water distribution pipes ( I-1-1-1) The straight line sections of the module are arranged in parallel close to the vertical partition (I-2-1), and the water inlet pipe (I-1-1-2) is divided into two paths and passes through the distribution area ( I-1) The side wall is connected to two groups of water distribution pipes (I-1-1-1) modules, and each branch is equipped with a control valve; The air distribution pipe (I-1-2-1) module is also in the form of a half-moon ring, and the straight sections of the two sets of air distribution pipe (I-1-2-1) modules are all close to the vertical partition (I-2-1) Arranged in parallel, the air delivery pipe (I-1-2-2) is divided into two paths and passes through the side wall of the distribution area (I-1) to connect to two groups of air distribution pipe (I-1-2-1) modules, and each There is also a control valve on the branch. 4. The in-situ flotation decalcification reactor for granular sludge as claimed in claim 1, wherein the vertical distance between the plane where the water distribution pipe (I-1-1-1) is located and the bottom surface of the distribution area is 30 ~50mm, the vertical distance between the plane where the air distribution pipe (I-1-2-1) is located and the bottom surface of the distribution area is 50~80mm. 5. The granular sludge in-situ flotation decalcification reactor according to claim 1, characterized in that the upper edge of the vertical partition (I-2-1) is at the same height as the lower edge of the three-phase separation zone , the lower edge of the vertical partition (I-2-1) extends into the distribution area by 10-30mm, and the vertical distance between the lower edge of the vertical partition (I-2-1) and the bottom surface of the distribution area (I-1) is 40- 60mm. 6. The granular sludge in-situ flotation decalcification reactor according to claim 1, characterized in that the inverted funnel (I-3-1-1) of the three-phase separator (I-3-1) ) lower edge is equal to the upper edge of the expansion section (I-3-6), and the area of the lower edge of the inverted funnel (I-3-1-1) is equal to the area of the three-phase separation zone (I-3) at the same height The ratio is 1:2.25; the upper edge of the upflow tube (I-3-1-2) is 30-50mm lower than the liquid level; the upper edge of the downflow tube (I-3-1-3) is 20-30mm higher than the liquid level , the lower edge of the downcomer (I-3-1-3) is 20-30mm higher than the upper edge of the inverted funnel (I-3-1-1). 7. The granular sludge in-situ flotation decalcification reactor according to claim 1, wherein the volume ratio of the decalcification liquid storage tank (II-1) to the reactor main body (I) is 1: 2~3. 8. The in-situ flotation decalcification reactor for granular sludge as claimed in claim 1, wherein the volume ratio of the reactor main body (I) to the biogas booster tank (III-3) is 1 : 0.3～0.5.