Coupling type circulation driving continuous flow aerobic granulation sewage treatment device and technology

Abstract

The coupling type circulation driving continuous flow aerobic granulation sewage treatment device comprises an anoxic column, an anaerobic column, an aeration column, an aerobic column, a water inlet peristaltic pump and an air pump, and is characterized in that stop valves are arranged on a first circulation pipe, a second circulation pipe, a third circulation pipe and a fourth circulation pipe, and liquid level difference and density difference exist among column bodies through aeration, so that sewage circulation flowing and treatment are achieved. The sewage treatment process comprises the following steps: a) feeding water and aerating; b) oxidizing organic matters; c) nitration; d) carrying out denitrification; e) synchronously carrying out nitrification and denitrification; (f) a phosphorus removal action stage; g) denitrification in the anoxic column; and h) carrying out a reaction in the anaerobic column. According to the sewage treatment device and process, through the design of self-circulation flowing and space independence and efficient utilization of aerobic granular sludge, the synergistic effect of organic matter degradation, nitrogen removal and phosphorus removal in the sewage treatment process is achieved, and the sewage treatment device and process have the remarkable advantages of being stable in operation, high in treatment efficiency and low in energy consumption.

Description

Technical Field

[0001] The present invention relates to a sewage treatment device and process, and more specifically, to a coupled circulation driven continuous flow aerobic granulation sewage treatment device and process. Background Art

[0002] At present, the most widely used processes in my country's sewage treatment field mainly include oxidation ditch, A2O (anaerobic-anoxic-aerobic) and traditional activated sludge method. The core principles of these processes are based on the traditional activated sludge method. By reasonably setting up aerobic and anaerobic zones, the metabolic action of microorganisms is used to degrade pollutants in sewage and achieve the goals of nitrogen removal and phosphorus removal. Among them, the oxidation ditch process occupies an important position in small and medium-sized sewage treatment plants due to its stable operation and simple operation; the A2O process has become the mainstream choice for municipal sewage treatment due to its ability to simultaneously remove nitrogen and phosphorus; and the traditional activated sludge method, as a classic process, is still widely used in many sewage treatment projects due to its mature technology and low cost.

[0003] With the increase in extreme water quality in industrial wastewater (such as high concentration of organic matter, high ammonia nitrogen, and difficult-to-degrade substances, etc.), the limitations of the traditional activated sludge method have gradually become apparent. First, its ability to resist shock loads is poor, and it is difficult to cope with the drastic fluctuations in water quality and water volume, which can easily lead to a decrease in treatment efficiency or even system collapse; second, the traditional process is prone to filamentous bacterial expansion during operation, causing the sludge settling performance to deteriorate, seriously affecting the effluent water quality; in addition, when traditional processes treat high-concentration industrial wastewater, the efficiency of nitrogen and phosphorus removal is often difficult to meet the increasingly stringent emission requirements. These problems are constantly magnified in sewage treatment, prompting the industry to actively explore new, more efficient and stable sewage treatment technologies.

[0004] Aerobic granular sludge (AGS) is a unique form of biofilm with advantages such as high solid content, good settling performance and low sludge production. However, the long granule culture time and instability during long-term operation are also important bottlenecks restricting the widespread application of AGS. In the past few decades, pilot studies and actual application cases have mainly adopted the SBR process. As of mid-2021, only about 100 wastewater treatment plants worldwide have adopted the AGS process. Typically, multiple SBR units need to be set up simultaneously to ensure continuous operation. The filling and draining steps in the SBR process pose special challenges and need to be completed in a short time and require the use of large pumping systems, resulting in fundamental changes in hydraulic conditions. First, the physical selection of particle settling rates in continuous flow reactors is challenging. Second, the design and operation of most granular sludge reactors are very different from existing continuous flow reactors, which makes it difficult and expensive to adapt and directly apply new technologies. Third, another major challenge is how to avoid damage to the physical structure and stability of AGS. Overcoming these challenges is a key focus of future AGS research. Innovative designs of continuous flow reactors will play an important role in promoting the integration of AGS into the mainstream. Therefore, advancing innovations in continuous flow configurations is critical to achieving future applications of continuous flow aerobic granular sludge technology. Summary of the invention

[0005] In order to overcome the disadvantages of the above technical problems, the present invention provides a coupled circulation driven continuous flow aerobic granulation sewage treatment device and process.

[0006] The coupled circulation driven continuous flow aerobic granulation sewage treatment device of the present invention comprises an anoxic column, an anaerobic column, an aeration column, an aerobic column, an inlet peristaltic pump, an air pump and an inlet pipe, wherein the inlet peristaltic pump is arranged on the inlet pipe, and the sewage to be treated enters the upper part of the anoxic column through the inlet peristaltic pump and the inlet pipe, and the upper part of the aerobic column is provided with a total water outlet; the upper part of the anoxic column is communicated with the bottom of the anaerobic column through a first circulation pipe, the upper part of the anaerobic column is communicated with the bottom of the aeration column through a second circulation pipe, the upper part of the aeration column is communicated with the bottom of the aerobic column through a third circulation pipe, and the upper part of the aerobic column is communicated with the bottom of the anoxic column through a fourth circulation pipe; the characteristic is that: the first circulation pipe, the second circulation pipe, the third circulation pipe and the fourth circulation pipe are respectively provided with a first stop valve, a second stop valve, a third stop valve and a fourth stop valve, and the aerobic column is inoculated or cultured with aerobic granular sewage. The anoxic column and the anaerobic column are inoculated with or cultured with anaerobic granular sludge; an aeration plate is arranged at the bottom of the aeration column, the aeration plate is connected to the air pump through a pipeline, the air pump aerates the aeration column through the aeration plate, aeration makes the liquid level of the aeration column higher than the liquid levels of the aerobic column and the anoxic column, and aeration makes the sewage density at the bottom of the aeration column lower than the density of the sewage in the anaerobic column, the sewage in the aeration column enters the aerobic column through the third circulation pipe under the action of the liquid level difference, the sewage in the aerobic column enters the anoxic column through the fourth circulation pipe, the sewage in the anaerobic column enters the aeration column through the second circulation pipe under the action of the density difference, and at the same time, under the action of the liquid level difference, the sewage in the anoxic column enters the anaerobic column through the first circulation pipe; the sewage is circulated in the anoxic column, the anaerobic column, the aeration column and the aerobic column to achieve treatment, and the treated sewage is discharged through the total outlet.

[0007] The coupled circulation driven continuous flow aerobic granulation sewage treatment device of the present invention has the following characteristics: the middle part of the first circulation pipe is communicated with the middle part of the anoxic column via the middle circulation pipe of the anoxic column, the middle part of the second circulation pipe is communicated with the middle part of the anaerobic column via the middle circulation pipe of the anaerobic column, the middle part of the third circulation pipe is communicated with the middle part of the aeration column via the middle circulation pipe of the aeration column, and the middle part of the fourth circulation pipe is communicated with the middle part of the aerobic column via the middle circulation pipe of the aerobic column; the middle circulation pipe of the anoxic column, the middle circulation pipe of the anaerobic column, the middle circulation pipe of the aeration column and the middle circulation pipe of the aerobic column are all provided with stop valves.

[0008] The coupled circulation driven continuous flow aerobic granulation sewage treatment device of the present invention has an anoxic column, an anaerobic column and an aerobic column respectively provided with an anoxic column mud discharge port, an anaerobic column mud discharge port and an aerobic column mud discharge port for discharging sludge at the bottom thereof.

[0009] The coupled circulation driven continuous flow aerobic granulation sewage treatment device of the present invention comprises an anoxic column water outlet and an anaerobic column water outlet respectively disposed on the upper parts of the anoxic column and the anaerobic column.

[0010] The coupled circulation driven continuous flow aerobic granulation sewage treatment device of the present invention has one or more anaerobic columns. When there are two or more vertical beams of the anaerobic column, the anoxic column is divided into two or more anaerobic columns through the first circulation pipe, and the two or more anaerobic columns are combined through the second circulation pipe and enter the aeration column.

[0011] The coupled circulation driven continuous flow aerobic granulation sewage treatment device of the present invention changes the rising flow rate of sewage in the aerobic column by adjusting the aeration amount of the aeration disk, and the adjustment range of the rising flow rate of sewage in the aerobic column is 20m / h~40m / h.

[0012] The sewage treatment process of the coupled circulation driven continuous flow aerobic granulation sewage treatment device of the present invention is characterized by being achieved through the following steps: a). Water intake and aeration: The sewage to be treated is pumped into the anoxic column through the water inlet pipe under the pumping action of the water inlet peristaltic pump. The aeration plate aerates the bottom of the aeration column under the action of the air pump. The bubbles generated by aeration in the aeration column rise and drive the liquid in the column to generate kinetic energy, the liquid level rises, and a liquid level difference is formed between the aeration column and the aerobic column and the anoxic column, so that the circulating water flows into the subsequent reaction columns in sequence; On the other hand, since the bubbles in the aeration column occupy the volume in the column, the relative density of the liquid in the aeration column will be lower than that in the anoxic column, so the water flows from the anoxic column with the lowest liquid level to the aeration column with the highest liquid level; the aeration in the aeration column not only provides dissolved oxygen for the circulating sewage entering the aerobic column, but also provides upward shear force for the granular sludge in the reaction column, thereby realizing an upflow granular sludge bed; b) Organic matter oxidation stage: The aerated water flow carries sufficient dissolved oxygen and enters the aerobic column from the third circulation pipe, at which time the dissolved oxygen concentration reaches the highest value; after the water flow in the aerobic column is mixed with the raw water at the bottom water inlet of the aerobic column, the COD in the influent is rapidly oxidized under sufficient dissolved oxygen conditions, while consuming a large amount of dissolved oxygen, thereby achieving the removal of organic matter in the sewage; c). Nitrification stage: While the COD of sewage is being oxidized in the aerobic column, ammonia nitrogen is also oxidized to nitrate by the action of nitrifying bacteria. This process also consumes a large amount of dissolved oxygen, further reducing the dissolved oxygen concentration in the water body; d). Denitrification stage: As the water flow in the aerobic column rises, the dissolved oxygen concentration gradually decreases. Under the action of denitrifying bacteria, nitrate is reduced to nitrogen gas, while consuming a large amount of COD to achieve efficient denitrification; e). Simultaneous nitrification and denitrification; the aerobic granular sludge in the aerobic column is a sphere with a multi-layer microbial structure. The outer layer of the aerobic granular sludge in the sphere forms an aerobic environment due to contact with higher dissolved oxygen, while the inner layer forms an anoxic environment due to limited dissolved oxygen penetration. This structure enables the granular sludge to undergo nitrification and denitrification reactions simultaneously, significantly improving the denitrification efficiency; f). Phosphorus removal stage: a large number of polyphosphate bacteria are enriched in the aerobic granular sludge in the aerobic column, which can efficiently absorb and remove phosphorus in the water even under high external dissolved oxygen conditions, thus achieving synchronous phosphorus removal; g). Denitrification in the anoxic column: Under the action of the liquid level difference, the sewage in the aerobic column enters the anoxic column through the fourth circulation pipe, and denitrification reaction is carried out under the action of denitrifying bacteria in the anaerobic granular sludge in the anoxic column, converting nitrate in the sewage into nitrogen gas, thereby achieving further removal of nitrate nitrogen; h). Reaction in the anaerobic column: The sewage in the anoxic column enters the bottom of the anaerobic column through the first circulation pipe. During the process of the sewage rising evenly from bottom to top in the anaerobic column, anaerobic phosphorus release and carbon source storage are achieved under the action of polyphosphate bacteria in the anaerobic granular sludge.

[0013] The beneficial effects of the present invention are as follows: the coupled circulation-driven continuous-flow aerobic granulation sewage treatment device and process of the present invention are provided with anoxic columns, anaerobic columns, aeration columns and aerobic columns which are sequentially connected via a circulation pipe, the sewage to be treated enters the anoxic columns via an inlet peristaltic pump and an inlet pipe, an aeration plate connected to an air pump is provided at the bottom of the aeration column, under the aeration action of the aeration plate on the bottom of the aeration column, not only is sufficient dissolved oxygen filled into the sewage, but also the liquid level of the aeration column is high-pressure, the liquid level of the aerobic column and the anoxic column, and the sewage density at the bottom of the aeration column is made smaller than the density of the sewage inside the anaerobic column, and the circulation flow of the sewage in the anoxic column, the anaerobic column, the aeration column and the aerobic column is realized under the action of the liquid level difference and the density difference; in the process of the sewage rising inside the aerobic column, the anoxic column and the anaerobic column, a high sludge concentration and a low substrate concentration are created in the column, which is conducive to the mutual collision of the sludges The collision and particle formation provide better hydraulic shear force, provide better hydraulic selection pressure for the screening of functional bacteria in the column, and are conducive to the cultivation of aerobic and anaerobic granular sludge; in this way, in the aerobic column, the uniform rising water flow creates suitable conditions for the growth of aerobic granular sludge, completes the degradation and nitrification reaction of organic matter, and converts ammonia nitrogen into nitrate nitrogen; the anoxic column is mainly used for denitrification reaction to complete the efficient removal of nitrate nitrogen; the anaerobic column mainly undertakes the role of anaerobic phosphorus release and carbon source storage, and realizes the independent distribution of anaerobic zone, anoxic zone and aerobic zone in space, forming granular sludge beds with clear functions; the present invention realizes the synergistic effect of organic matter degradation, denitrification and phosphorus removal in the sewage treatment process through self-circulating flow, spatially independent zoning design and efficient utilization of aerobic granular sludge, and has the significant advantages of stable operation, high treatment efficiency and low energy consumption.

[0014] At the same time, floc sludge comes from the disintegration of new sludge and oversized particles. It has a larger specific surface area in low-intensity wastewater and a faster growth and metabolism rate than general granular sludge. However, floc sludge will flow out of the system with the effluent at a higher rising velocity, thus achieving the washing of floc sludge in the system. The dominant growth of functional bacteria in the undischarged floc sludge provides favorable conditions for the aggregation and growth of floc sludge into small particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a coupled circulation driven continuous flow aerobic granulation sewage treatment device of the present invention; Figure 2 It is a pollutant concentration change detection diagram of the sewage treatment process in the present invention; Figure 3 It is a phosphorus removal change detection diagram of the sewage treatment process in the present invention; Figure 4 This is a particle effect detection diagram of the sewage treatment process in the present invention.

[0016] In the figure: 1 anoxic column, 2 anaerobic column, 3 aeration column, 4 aerobic column, 5 sewage to be treated, 6 water inlet peristaltic pump, 7 water inlet pipe, 8 total water outlet, 9 first circulation pipe, 10 second circulation pipe, 11 third circulation pipe, 12 fourth circulation pipe, 13 first stop valve, 14 second stop valve, 15 third stop valve, 16 fourth stop valve, 17 middle circulation pipe of anoxic column, 18 middle circulation pipe of anaerobic column, 19 middle circulation pipe of aeration column, 20 middle circulation pipe of aerobic column, 21 mud discharge port of anoxic column, 22 mud discharge port of anaerobic column, 23 mud discharge port of aerobic column, 24 aeration plate, 25 air pump, 26 water outlet of anoxic column, 27 water outlet of anaerobic column, 28 anaerobic granular sludge, 29 aerobic granular sludge. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0018] like Figure 1As shown, a schematic diagram of the structure of the coupled circulation driven continuous flow aerobic granulation sewage treatment device of the present invention is given, which is composed of anoxic column 1, anaerobic column 2, aeration column 3, aerobic column 4, water inlet peristaltic pump 6, water inlet pipe 7, aeration plate 24 and air pump 25. The upper part of the anoxic column 1 is connected to the bottom of the anaerobic column 2 through the first circulation pipe 9, the upper part of the anaerobic column 2 is connected to the bottom of the aeration column 3 through the second circulation pipe 10, the upper part of the aeration column 3 is connected to the bottom of the aerobic column 4 through the third circulation pipe 11, and the upper part of the aerobic column 4 is connected to the bottom of the anoxic column 1 through the fourth circulation pipe 12, so as to ensure that the sewage 5 to be treated can circulate among the anoxic column 1, the anaerobic column 2, the aeration column 3 and the aerobic column 4. The water inlet pipe 7 is connected to the upper part of the anoxic column 1, and the water inlet peristaltic pump 6 is arranged on the water inlet pipe 7. The sewage 5 to be treated is pumped to the upper part of the anoxic column 1 through the water inlet peristaltic pump 6 and the water inlet pipe 7.

[0019] The aerobic column 4 is inoculated with aerobic granular sludge 29, which can also be obtained by inoculating floc sludge culture. The anoxic column 1 and the anaerobic column 2 are both inoculated with anaerobic granular sludge 28, which can also be obtained by inoculating floc sludge culture.

[0020] The aeration plate 24 shown is arranged at the bottom of the aeration column 3, and the aeration plate 24 is connected to the air pump 25. Under the air supply of the air pump 25, the bottom of the aeration column 3 is aerated through the aeration plate 24. The aeration makes the liquid level in the aeration column 3 higher than the liquid level in the aerobic column 4, and the density of sewage at the bottom of the aeration column 3 is lower than the density of sewage in the anaerobic column 2. Under the action of the liquid level difference, the sewage in the aeration column 3 flows from the aeration column 3 to the aerobic column 4, and under the action of the density difference, the sewage in the anaerobic column 2 flows into the aeration column 3, so as to realize the circulation of sewage, thereby making the sewage treatment meet the standards.

[0021] The first circulation pipe 9, the second circulation pipe 10, the third circulation pipe 11 and the fourth circulation pipe 12 are respectively provided with a first stop valve 13, a second stop valve 14, a third stop valve 15 and a fourth stop valve 16. By adjusting the opening of the stop valve, the flow rate of the sewage flowing through the corresponding circulation pipe can be controlled, and then the flow rate of the sewage in the entire sewage treatment device can be adjusted.

[0022] The middle part of the first circulation pipe 9 shown is connected to the middle part of the anoxic column 1 via the anoxic column middle circulation pipe 17, the middle part of the second circulation pipe 10 is connected to the middle part of the anaerobic column 2 via the anaerobic column middle circulation pipe 18, the middle part of the third circulation pipe 11 is connected to the middle part of the aeration column 3 via the aeration column middle circulation pipe 19, the middle part of the fourth circulation pipe 12 is connected to the middle part of the aerobic column 4 via the aerobic column middle circulation pipe 20, and the anoxic column middle circulation pipe 17, the anaerobic column middle circulation pipe 18, the aeration column middle circulation pipe 19 and the aerobic column middle circulation pipe 20 are all provided with stop valves. The design of circulation pipes at different heights can be adjusted and optimized to meet process requirements. By changing the length and resistance of the reflux path, precise control of fluid dynamics can be achieved to adjust the flow rate. The circulation flow rate can be increased by opening the corresponding middle circulation pipe. For example, if it is necessary to increase the flow rate of sewage from anoxic column 1 to anaerobic column 2, the middle circulation pipe 17 of the anoxic column is opened to increase the flow rate of sewage from anoxic column 1 to anaerobic column 2.

[0023] The bottoms of the anoxic column 1, anaerobic column 2 and aerobic column 4 are respectively provided with anoxic column mud discharge port 21, anaerobic column mud discharge port 22 and aerobic column mud discharge port 23, and the upper part of the aerobic column 4 is provided with a total water outlet 8, and the treated sewage is discharged through the total water outlet 8. The upper ends of the anoxic column 1 and the anaerobic column 2 are respectively provided with anoxic column water outlet 26 and anaerobic column water outlet 27.

[0024] The number of anaerobic columns 2 is one or more. When there are two or more vertical beams of the anaerobic column 2, the anoxic column 1 enters two or more anaerobic columns 2 after being split by the first circulation pipe 9, and the two or more anaerobic columns 2 enter the aeration column 3 after being merged by the second circulation pipe 10. When multiple anaerobic columns 2 are arranged in parallel, the shut-off valve of the water inlet pipe of one anaerobic column 2 can also be closed to use it as a hydrolysis acidification column.

[0025] The upflow effect of the multi-stage circulation pipeline reaction column is used to achieve uniform water quality. The multi-stage circulation pipeline is used to achieve uniform sewage distribution and avoid short-flow and dead zones. The circulation volume is determined by the aeration volume in the aeration column 2, which can change the upflow velocity of the aerobic column 4. The adjustment range of the sewage upflow velocity in the aerobic column 4 is 20m / h~40m / h. According to the flexible combination of treatment scale, each functional zone (i.e., anoxic column 1, anaerobic column 2, aeration column 3, aerobic column 4) is connected by an optimized circulation pipe design to achieve the optimization of hydraulic flow state.

[0026] The coupled circulation-driven continuous flow aerobic granulation sewage treatment device and process of the present invention adopts an operation mode in which aeration and granular sludge reaction columns are separated. By separately setting an aeration column 3, the water flow distribution and dissolved oxygen gradient are significantly optimized, forming a stable selective pressure and promoting the stable growth of granular sludge. At the same time, as the water flow rises, the dissolved oxygen content shows an obvious gradient change, so that reactions such as organic oxidation, nitrification and denitrification can be carried out efficiently in different areas. The sewage treatment process of the present invention is characterized in that it is achieved by the following steps: a). Water intake and aeration: The sewage to be treated is pumped into the anoxic column through the water inlet pipe under the pumping action of the water inlet peristaltic pump. The aeration plate aerates the bottom of the aeration column under the action of the air pump. The bubbles generated by aeration in the aeration column rise and drive the liquid in the column to generate kinetic energy, the liquid level rises, and a liquid level difference is formed between the aeration column and the aerobic column and the anoxic column, so that the circulating water flows into the subsequent reaction columns in sequence; On the other hand, since the bubbles in the aeration column occupy the volume in the column, the relative density of the liquid in the aeration column will be lower than that in the anoxic column, so the water flows from the anoxic column with the lowest liquid level to the aeration column with the highest liquid level; the aeration in the aeration column not only provides dissolved oxygen for the circulating sewage entering the aerobic column, but also provides upward shear force for the granular sludge in the reaction column, thereby realizing an upflow granular sludge bed; b) Organic matter oxidation stage: The aerated water flow carries sufficient dissolved oxygen and enters the aerobic column from the third circulation pipe, at which time the dissolved oxygen concentration reaches the highest value; after the water flow in the aerobic column is mixed with the raw water at the bottom water inlet of the aerobic column, the COD in the influent is rapidly oxidized under sufficient dissolved oxygen conditions, while consuming a large amount of dissolved oxygen, thereby achieving the removal of organic matter in the sewage; c). Nitrification stage: While the COD of sewage is being oxidized in the aerobic column, ammonia nitrogen is also oxidized to nitrate by the action of nitrifying bacteria. This process also consumes a large amount of dissolved oxygen, further reducing the dissolved oxygen concentration in the water body; d). Denitrification stage: As the water flow in the aerobic column rises, the dissolved oxygen concentration gradually decreases. Under the action of denitrifying bacteria, nitrate is reduced to nitrogen gas, while consuming a large amount of COD to achieve efficient denitrification; e). Simultaneous nitrification and denitrification; the aerobic granular sludge in the aerobic column is a sphere with a multi-layer microbial structure. The outer layer of the aerobic granular sludge in the sphere forms an aerobic environment due to contact with higher dissolved oxygen, while the inner layer forms an anoxic environment due to limited dissolved oxygen penetration. This structure enables the granular sludge to undergo nitrification and denitrification reactions simultaneously, significantly improving the denitrification efficiency; f). Phosphorus removal stage: a large number of polyphosphate bacteria are enriched in the aerobic granular sludge in the aerobic column, which can efficiently absorb and remove phosphorus in the water even under high external dissolved oxygen conditions, thus achieving synchronous phosphorus removal; g). Denitrification in the anoxic column: Under the action of the liquid level difference, the sewage in the aerobic column enters the anoxic column through the fourth circulation pipe, and denitrification reaction is carried out under the action of denitrifying bacteria in the anaerobic granular sludge in the anoxic column, converting nitrate in the sewage into nitrogen gas, thereby achieving further removal of nitrate nitrogen; h). Reaction in the anaerobic column: The sewage in the anoxic column enters the bottom of the anaerobic column through the first circulation pipe. During the process of the sewage rising evenly from bottom to top in the anaerobic column, anaerobic phosphorus release and carbon source storage are achieved under the action of polyphosphate bacteria in the anaerobic granular sludge.

[0027] In order to illustrate the sewage treatment effect of the sewage treatment device and process of the present invention, the hydraulic retention time is set to 18 h, and the continuous operation is 130 days. The COD solubility in the influent of the sewage 5 to be treated is 1000 mg / L, the ammonia nitrogen in the influent is (250±50) mg / L, the effective volume of the aerobic column 4 is 26.86 L, and the influent volume is 1.49 L / h; the circulation flow rate is controlled at (130±60) L / h, and the rising flow rate is (15±5). Figure 2 , Figure 3 and Figure 4 As shown in the figure, the changes in pollutant concentration, phosphorus removal and particle effect detection diagrams are given respectively. It can be seen that when the hydraulic retention time is 18 h, the process always ensures that the average concentrations of effluent ammonia nitrogen and total nitrogen remain below 5 mg / L and 15 mg / L respectively. The process always ensures that the phosphorus removal rate can be stabilized at 70%. The microscopic conditions of particles during the process operation, among which the median particle size of aerobic granular sludge is between 340μm and 600μm, with good sedimentation performance. The suspended solids in the effluent can be maintained at 30 mg / L ~60 mg / L.

Claims

1. A coupled circulation driven continuous flow aerobic granulation sewage treatment device, comprising an anoxic column (1), an anaerobic column (2), an aeration column (3), an aerobic column (4), an inlet peristaltic pump (6), an air pump (25) and an inlet pipe (7), wherein the inlet peristaltic pump is arranged on the inlet pipe, and the sewage to be treated (5) enters the upper part of the anoxic column through the inlet peristaltic pump and the inlet pipe, and the upper part of the aerobic column is provided with a total water outlet (8); the upper part of the anoxic column is communicated with the bottom of the anaerobic column through a first circulation pipe (9), the upper part of the anaerobic column is communicated with the bottom of the aeration column through a second circulation pipe (10), the upper part of the aeration column is communicated with the bottom of the aerobic column through a third circulation pipe (11), and the upper part of the aerobic column is communicated with the bottom of the anoxic column through a fourth circulation pipe (12); characterized in that: The first circulation pipe, the second circulation pipe, the third circulation pipe and the fourth circulation pipe are respectively provided with a first stop valve (13), a second stop valve (14), a third stop valve (15) and a fourth stop valve (16); aerobic granular sludge (29) is inoculated or cultured in the aerobic column, and anaerobic granular sludge (28) is inoculated or cultured in the anoxic column and the anaerobic column; an aeration plate (24) is provided at the bottom of the aeration column, the aeration plate is connected to an air pump (25) via a pipeline, and the air pump aerates the aeration column via the aeration plate, and aeration causes the liquid level of the aeration column to be higher than that of the aerobic column and the anoxic column. The liquid level is set, and aeration makes the density of sewage at the bottom of the aeration column lower than the density of sewage in the anaerobic column. Under the action of the liquid level difference, the sewage in the aeration column enters the aerobic column through the third circulation pipe, and the sewage in the aerobic column enters the anoxic column through the fourth circulation pipe. Under the action of the density difference, the sewage in the anaerobic column enters the aeration column through the second circulation pipe. At the same time, under the action of the liquid level difference, the sewage in the anoxic column enters the anaerobic column through the first circulation pipe. The sewage is treated by circulating in the anoxic column, the anaerobic column, the aeration column and the aerobic column, and the treated sewage is discharged through the total outlet.

2. The coupled circulation driven continuous flow aerobic granulation sewage treatment device according to claim 1 is characterized in that: The middle part of the first circulation pipe (9) is communicated with the middle part of the anoxic column (1) via the anoxic column middle circulation pipe (17), the middle part of the second circulation pipe (10) is communicated with the middle part of the anaerobic column via the anaerobic column middle circulation pipe (18), the middle part of the third circulation pipe (11) is communicated with the middle part of the aeration column via the aeration column middle circulation pipe (19), and the middle part of the fourth circulation pipe (12) is communicated with the middle part of the aerobic column via the aerobic column middle circulation pipe (20); the anoxic column middle circulation pipe, the anaerobic column middle circulation pipe, the aeration column middle circulation pipe and the aerobic column middle circulation pipe are all provided with stop valves.

3. The coupled circulation driven continuous flow aerobic granulation sewage treatment device according to claim 1 or 2, characterized in that: The bottoms of the anoxic column (1), the anaerobic column (2) and the aerobic column (4) are respectively provided with an anoxic column mud discharge port (21), an anaerobic column mud discharge port (22) and an aerobic column mud discharge port (23) for discharging sludge.

4. The coupled circulation driven continuous flow aerobic granulation sewage treatment device according to claim 1 or 2, characterized in that: An anoxic column water outlet (26) and an anaerobic column water outlet (27) are respectively arranged at the upper parts of the anoxic column (1) and the anaerobic column (2).

5. The coupled circulation driven continuous flow aerobic granulation sewage treatment device according to claim 1 or 2, characterized in that: The number of the anaerobic columns (2) is one or more; when there are two or more vertical beams of the anaerobic columns, the anoxic column is split into two or more anaerobic columns via the first circulation pipe (9), and the two or more anaerobic columns are merged into the aeration column (3) via the second circulation pipe (10).

6. The coupled circulation driven continuous flow aerobic granulation sewage treatment device according to claim 1 or 2, characterized in that: The rising flow rate of the sewage in the aerobic column (4) is changed by adjusting the aeration volume of the aeration plate (24), and the adjustment range of the rising flow rate of the sewage in the aerobic column is 20 m / h to 40 m / h.

7. A sewage treatment process based on the coupled circulation driven continuous flow aerobic granulation sewage treatment device according to claim 1, characterized in that: This is accomplished by following these steps: a). Water intake and aeration: The sewage to be treated is pumped into the anoxic column through the water inlet pipe under the pumping action of the water inlet peristaltic pump. The aeration plate aerates the bottom of the aeration column under the action of the air pump. The bubbles generated by aeration in the aeration column rise and drive the liquid in the column to generate kinetic energy, the liquid level rises, and a liquid level difference is formed between the aeration column and the aerobic column and the anoxic column, so that the circulating water flows into the subsequent reaction columns in sequence; On the other hand, since the bubbles in the aeration column occupy the volume in the column, the relative density of the liquid in the aeration column will be lower than that in the anoxic column, so the water flows from the anoxic column with the lowest liquid level to the aeration column with the highest liquid level; the aeration in the aeration column not only provides dissolved oxygen for the circulating sewage entering the aerobic column, but also provides upward shear force for the granular sludge in the reaction column, thereby realizing an upflow granular sludge bed; b) Organic matter oxidation stage: The aerated water flow carries sufficient dissolved oxygen and enters the aerobic column from the third circulation pipe, at which time the dissolved oxygen concentration reaches the highest value; after the water flow in the aerobic column is mixed with the raw water at the bottom water inlet of the aerobic column, the COD in the influent is rapidly oxidized under sufficient dissolved oxygen conditions, while consuming a large amount of dissolved oxygen, thereby achieving the removal of organic matter in the sewage; c). Nitrification stage: While the COD of sewage is being oxidized in the aerobic column, ammonia nitrogen is also oxidized to nitrate by the action of nitrifying bacteria. This process also consumes a large amount of dissolved oxygen, further reducing the dissolved oxygen concentration in the water body; d). Denitrification stage: As the water flow in the aerobic column rises, the dissolved oxygen concentration gradually decreases. Under the action of denitrifying bacteria, nitrate is reduced to nitrogen gas, while consuming a large amount of COD to achieve efficient denitrification; e). Simultaneous nitrification and denitrification; the aerobic granular sludge in the aerobic column is a sphere with a multi-layer microbial structure. The outer layer of the aerobic granular sludge in the sphere forms an aerobic environment due to contact with higher dissolved oxygen, while the inner layer forms an anoxic environment due to limited dissolved oxygen penetration. This structure enables the granular sludge to undergo nitrification and denitrification reactions simultaneously, significantly improving the denitrification efficiency; f). Phosphorus removal stage: a large number of polyphosphate bacteria are enriched in the aerobic granular sludge in the aerobic column, which can efficiently absorb and remove phosphorus in the water even under high external dissolved oxygen conditions, thus achieving synchronous phosphorus removal; g). Denitrification in the anoxic column: Under the action of the liquid level difference, the sewage in the aerobic column enters the anoxic column through the fourth circulation pipe, and denitrification reaction is carried out under the action of denitrifying bacteria in the anaerobic granular sludge in the anoxic column, converting nitrate in the sewage into nitrogen gas, thereby achieving further removal of nitrate nitrogen; h). Reaction in the anaerobic column: The sewage in the anoxic column enters the bottom of the anaerobic column through the first circulation pipe. During the process of the sewage rising evenly from bottom to top in the anaerobic column, anaerobic phosphorus release and carbon source storage are achieved under the action of polyphosphate bacteria in the anaerobic granular sludge.

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