Pre-phosphorus recovery device for multi-stage fermentation acid production

Abstract

The invention relates to the technical field of sewage treatment, in particular to a multistage fermentation acid production preposed phosphorus recovery device which comprises an aerated grit chamber, a fermentation primary sedimentation tank, a preposed sequencing batch type phosphorus removal system, a treatment and discharge system and a recovery system, the aerated grit chamber is connected with an external sewage pipeline, the fermentation primary sedimentation tank is arranged on one side of the aerated grit chamber, and the preposed sequencing batch type phosphorus removal system is arranged on the other side of the aerated grit chamber. The front sequencing batch dephosphorization system is communicated with the fermentation primary sedimentation tank, and the treatment and discharge system is communicated with one side of the front sequencing batch dephosphorization system. Compared with the prior art, by arranging the fermentation primary sedimentation tank and reasonably controlling the hydraulic retention time and the sludge concentration, not only are fermentation conditions in the tank optimized, but also unnecessary stirring energy consumption and excessive sludge treatment requirements are reduced, the operation cost is reduced, and meanwhile, the sludge load of a subsequent system is effectively reduced.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a multi-stage fermentation acid production pre-phosphorus recovery device. Background Art

[0002] Phosphorus is a non-renewable mineral resource. The current phosphate reserves in the world are only enough to be consumed for a hundred years. The continuous increase in the world population has led to an increasing demand for phosphate fertilizers in agricultural production. The existing phosphate resources will hardly meet the needs of human development. With the further deepening of the concept of resource utilization, sewage treatment is gradually changing from the concept of "pollutant removal" to "resource recovery". Studies have shown that recycling phosphorus from sewage around the world can meet 15%-20% of the global phosphorus demand. Therefore, the research and development and application of efficient phosphorus recovery technology have received extensive attention from scholars at home and abroad.

[0003] At present, the phosphorus recovery process in sewage treatment plants is mainly a side stream phosphorus recovery mode, which is based on the theory of enhanced biological phosphorus removal. First, the phosphorus in sewage is enriched into residual sludge through traditional nitrogen removal and phosphorus removal processes such as AAO or oxidation ditch, and then phosphorus is recovered from the phosphorus-rich residual sludge. The phosphorus in the residual sludge is released through anaerobic digestion of the sludge, or incinerated to obtain ash and then leached to obtain a phosphorus solution. Although the technology of recovering phosphorus from residual sludge has been widely used in foreign sewage treatment plants, it still has the disadvantages of complex process flow, large sludge output, low phosphorus recovery efficiency (40% to 79%), and high heavy metal content in the recovered product.

[0004] Another feasible phosphorus recovery mode is the mainstream phosphorus recovery process that directly removes the enriched phosphorus in the liquid phase. This process is mainly based on the biofilm process, which has the advantages of simple process flow, small sludge output, high recovery efficiency, etc., and is more in line with the development direction of sewage resource utilization. However, at present, most biofilm processes require the addition of high-concentration carbon sources to promote anaerobic phosphorus release, or to increase the utilization rate of carbon sources by extending the anaerobic hydraulic retention time, thereby increasing the operating cost and limiting the industrial application of the process.

[0005] Therefore, the present application discloses a multi-stage fermentation acid production pre-phosphorus recovery device. Summary of the invention

[0006] In view of this, the purpose of the present invention is to propose a multi-stage fermentation acid production pre-phosphorus recovery device to solve the problems of complex side stream phosphorus recovery process, large sludge output, low phosphorus recovery efficiency, high heavy metal content in recovered products, and the need to add high-concentration carbon source and long anaerobic hydraulic retention time in the mainstream biofilm phosphorus recovery process.

[0007] Based on the above purpose, the present invention provides a multi-stage fermentation acid production pre-phosphorus recovery device, including an aerated grit tank, a fermentation primary sedimentation tank, a pre-sequencing batch phosphorus removal system, a treatment and discharge system and a recovery system, wherein the aerated grit tank is connected to an external sewage pipe, the fermentation primary sedimentation tank is arranged on one side of the aerated grit tank, the pre-sequencing batch phosphorus removal system is connected to the fermentation primary sedimentation tank, and the treatment and discharge system is connected to one side of the pre-sequencing batch phosphorus removal system;

[0008] The fermentation primary sedimentation tank is used to mix sewage with return excess sludge, and convert macromolecular organic matter into volatile fatty acids through fermentation and acid production, thereby providing a carbon source for subsequent anaerobic phosphorus release and denitrification;

[0009] The pre-sequencing batch phosphorus removal system comprises at least two groups of sequencing batch anaerobic phosphorus release tanks that operate alternately, and the pre-sequencing batch phosphorus removal system is used to separate and enrich the phosphorus-rich supernatant;

[0010] The recovery system is connected to the anaerobic phosphorus release tank through a pipeline, and the recovery system includes a stirring module and a pH adjustment system, and the recovery system is used for recovering and reusing phosphorus resources;

[0011] The treatment and discharge system includes an anoxic tank, an aerobic tank, a secondary sedimentation tank and a deep treatment tank in sequence, wherein the anoxic tank, the aerobic tank, the secondary sedimentation tank and the deep treatment tank are all connected through pipelines, and one side of the anoxic tank is connected to the pre-sequential batch phosphorus removal system;

[0012] A sludge treatment system and a sludge return pipe are also provided on one side of the secondary sedimentation tank. The sludge treatment system is used to transport a part of the residual sludge. One side of the sludge treatment system is also connected to one side of the fermentation primary sedimentation tank. Two interfaces are provided on the sludge return pipe, one of which is connected to the anoxic tank for returning 80% to 98.5% of the residual sludge in the secondary sedimentation tank, and the other interface is connected to the fermentation primary sedimentation tank for returning 1.5% to 4% of the residual sludge in the secondary sedimentation tank. A digestion liquid return pipe is also provided on one side of the aerobic tank, and the other end of the digestion liquid return pipe is connected to the anoxic tank.

[0013] Preferably, a primary sedimentation tank water inlet and a primary sedimentation tank return port are provided at one end of the fermentation primary sedimentation tank, and valves are provided on the primary sedimentation tank water inlet and the primary sedimentation tank return port. The primary sedimentation tank water inlet is connected with the aerated grit tank for the entry of sewage, and the primary sedimentation tank return port is connected with the sludge return pipe for sludge return. A sludge hopper is provided at the bottom of the fermentation primary sedimentation tank, and a mud discharge pipe is provided at the bottom of the sludge hopper. A sludge chain is provided on one side of the fermentation primary sedimentation tank, and the mud discharge pipe is connected with the sludge treatment system.

[0014] Preferably, the hydraulic retention time of the primary fermentation sedimentation tank is 2 to 3 hours, the sludge concentration at the bottom of the primary fermentation sedimentation tank is set to be maintained at 7000 to 8000 mg / L, and the effluent mixed liquor concentration of the primary fermentation sedimentation tank is set to be 2000 to 3000 mg / L.

[0015] Preferably, the sequencing batch anaerobic phosphate release tank is arranged in a circular shape, a phosphorus release water inlet is arranged on the upper side of the sequencing batch anaerobic phosphate release tank, a phosphorus release tank sludge outlet is arranged on the lower side of the sequencing batch anaerobic phosphate release tank, a decanter and an agitator are arranged inside the sequencing batch anaerobic phosphate release tank, the internal dissolved oxygen concentration in the sequencing batch anaerobic phosphate release tank is maintained below 0.5 mg / L, and the hydraulic retention time is 3 to 4 hours, the supernatant in the sequencing batch anaerobic phosphate release tank is separated from the sludge by a decanter, a sludge layer sensor is arranged inside the decanter, and the lowest water level of the decanter is at least 0.5 meters away from the upper surface of the sludge layer to prevent water pollution.

[0016] Preferably, the recovery system includes a phosphorus recovery reaction tank connected to the two sequencing batch anaerobic phosphorus release tanks, a supernatant inlet is provided on one side of the phosphorus recovery reaction tank, and the supernatant inlet is used to add supernatant, a first feed pipe and a second feed pipe are respectively provided on both sides of the top of the phosphorus recovery reaction tank, and a phosphorus-rich product discharge pipe is provided at the bottom of the phosphorus recovery reaction tank, the first feed pipe is used to place a phosphorus recovery chemical precipitant, the second feed pipe is connected to the sequencing batch anaerobic phosphorus release tank, and the second feed pipe is used to place the phosphorus-rich supernatant inside the sequencing batch anaerobic phosphorus release tank, and an outlet pipe is also provided on one side of the bottom of the phosphorus recovery reaction tank.

[0017] Preferably, a pH detection and adjustment system is provided on one side of the phosphorus recovery reaction tank. When the pH inside the phosphorus recovery reaction tank is lower than 8.5, the pH adjustment system automatically adds an alkaline regulator until the pH reaches 10.

[0018] Preferably, the chemical precipitant placed inside the phosphorus recovery reaction tank is a magnesium salt, which can react to generate magnesium ammonium phosphate hexahydrate, and the optimal reaction conditions are a pH value of 8.5 to 10, wherein the Mg / P ratio is 1.5:1, and the phosphorus recovery rate can reach 85%.

[0019] Preferably, a fixed cylinder is fixedly installed on the internal top of the phosphorus recovery reaction tank, a filter cylinder is rotatably installed below the fixed cylinder, a bearing is arranged between the fixed cylinder and the filter cylinder, a reciprocating screw rod is rotatably installed in the middle part of the inner part of the separation cylinder, a second rotating motor is fixedly installed in the middle part of the top of the separation cylinder, the output end of the second rotating motor is fixedly connected to the reciprocating screw rod, a connecting seat is fixedly sleeved on one side of the reciprocating screw rod, the connecting seat is fixedly connected to the filter cylinder, a filter element is arranged inside the filter cylinder, a spiral stirring bar is also arranged inside the filter cylinder, and the bottom end of the stirring bar is fixedly connected to the connecting seat.

[0020] Preferably, a fixed plate is fixedly installed at the bottom of the phosphorus recovery reaction tank, a rotating ring is rotatably installed above the fixed plate, a drop-out port is opened in the middle of the fixed plate, the drop-out port is connected to the phosphorus-rich product discharge pipe, a plurality of opening and closing plates are rotatably installed on the inner side of the top of the drop-out port, a plurality of connecting plates are rotatably installed on one side of the rotating ring, a plurality of connecting plates are rotatably connected to one side of the opening and closing plate, the drop-out port is closed when the opening and closing plates approach each other, and the drop-out port is opened when the opening and closing plates move away from each other, a plurality of limit grooves are equidistantly opened on the outer circumference of the rotating ring, and a plurality of limit columns slidably installed inside the limit grooves are provided on the top of the fixed plate.

[0021] Preferably, an extension rod is provided on one side of the top surface of the rotating ring, a trigger block is provided on the top of the extension rod, a moving sleeve is threadedly connected to the outer surface of the reciprocating screw rod, a first positioning rod and a second positioning rod are provided on both sides of the moving sleeve, a first push block and a second push block are provided at the bottom ends of the first positioning rod and the second positioning rod, the height of the first push block is higher than the height of the second push block, the bottom surface of the first push block is an inclined surface, and the top surface of the second push block is an inclined surface.

[0022] Beneficial effects of the present invention:

[0023] 1. This multi-stage fermentation acid production pre-phosphorus recovery device is provided with a fermentation primary sedimentation tank. By setting the hydraulic retention time to 2 to 3 hours, the sewage and return sludge are fully mixed and fermented in the tank, which can efficiently convert macromolecular organic matter into volatile fatty acids (VFAs), provide high-quality carbon sources for subsequent anaerobic phosphorus release and denitrification denitrification, and avoid organic matter degradation loss caused by long-term fermentation, thereby improving carbon source utilization efficiency. The sludge concentration at the bottom of the tank is controlled at 7000 to 8000 mg / L, maintaining a high activated sludge load, and enhancing the fermentation primary sedimentation tank for organic matter. In order to improve the processing capacity and prevent the fermentation efficiency from decreasing due to too low sludge concentration, the effluent mixed liquor concentration is set at 2000 to 3000 mg / L to ensure that the effluent is rich in small molecular organic matter to meet the carbon source demand of subsequent treatment units, while reducing the impact of large particle suspended matter on subsequent processes and improving the stability and operation efficiency of the system. In addition, by reasonably controlling the hydraulic retention time and sludge concentration, not only the fermentation conditions in the pool are optimized, but also unnecessary stirring energy consumption and the need to treat excessive sludge are reduced, thereby reducing operating costs and effectively reducing the sludge load of subsequent systems.

[0024] 2. This multi-stage fermentation acid production pre-phosphorus recovery device is provided with a recovery system. The phosphorus recovery reaction tank is respectively fed with chemical precipitants and phosphorus-rich supernatant through the first feed pipe and the second feed pipe, and is equipped with a pH detection and adjustment system to monitor and adjust the pH in the tank in real time. When the pH value is lower than 8.5, an alkaline regulator is automatically added to adjust the pH to the optimal range of 8.5 to 10 to ensure that magnesium ions react fully with phosphate and ammonium ions, thereby achieving a phosphorus recovery rate of up to 85%. The struvite generated by precipitation reaction in the tank is discharged through the phosphorus-rich product discharge pipe at the bottom, ensuring the continuous operation of the reaction tank. It realizes efficient phosphorus recovery and simultaneously removes nitrogen and phosphorus in wastewater, achieving the dual goals of resource utilization and pollution control, while avoiding the heavy metal pollution problem existing in traditional phosphorus recovery processes. The generated products are of high purity and high added value, which meets the needs of sustainable development. In addition, this process utilizes the internal carbon source in the phosphorus-rich supernatant to replace the high-concentration external carbon source, which significantly reduces the operating cost. At the same time, it shortens the anaerobic hydraulic retention time by optimizing the reaction conditions, effectively overcoming the shortcomings of the mainstream biofilm phosphorus recovery process that requires the addition of high-concentration carbon sources and long anaerobic hydraulic retention time, and significantly improves the economy and environmental protection of wastewater treatment.

[0025] 3. The multi-stage fermentation acid production pre-phosphorus recovery device is provided with a phosphorus recovery reaction tank. The phosphorus recovery reaction tank realizes a full mixing reaction of phosphorus-rich supernatant and chemical precipitant through a filter cartridge and a spiral stirring bar, and efficiently generates struvite particles. The filter element in the filter cartridge is used for solid-liquid separation, and the clear liquid is discharged through the bottom outlet pipe to ensure that the separation of liquid and solid is clean and thorough. After the struvite particles are deposited at the bottom of the filter cartridge, the reciprocating screw rod is driven by the second rotating motor to move, driving the first push block and the second push block to link the extension rod, accurately controlling the opening and closing of the drop port, so that the struvite particles are smoothly discharged to the phosphorus-rich product discharge pipe. The height difference between the first push block and the second push block ensures that the drop port moves smoothly and resets stably, realizing the automatic discharge of struvite and the continuous operation of the equipment, optimizing the overall efficiency of the reaction tank, improving product quality, and simplifying the operation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the process of the present invention;

[0028] Figure 2 This is a schematic diagram of the structure of the primary fermentation sedimentation tank of the present invention;

[0029] Figure 3 It is a schematic diagram of the structure of the sequencing batch anaerobic phosphorus release tank of the present invention;

[0030] Figure 4 This is a schematic diagram of the structure of the phosphorus recovery reaction tank of the present invention;

[0031] Figure 5 This is a schematic diagram of the three-dimensional structure of the phosphorus recovery reaction tank of the present invention;

[0032] Figure 6 It is a schematic diagram of the partial cross-sectional structure of the phosphorus recovery reaction tank of the present invention;

[0033] Figure 7 This is a schematic diagram of the internal structure of the phosphorus recovery reaction tank of the present invention;

[0034] Figure 8 For the present invention Figure 7 The enlarged structural diagram at A in the middle;

[0035] Fig. 9 It is a schematic diagram of the filter cartridge structure of the present invention;

[0036] Fig.10 It is a schematic diagram of the structure of the opening and closing plate of the present invention;

[0037] Fig.11 It is a schematic diagram of the structure of the reciprocating screw rod and the movable sleeve of the present invention.

[0038] The markings in the figure are:

[0039] 1. Fermentation primary sedimentation tank; 2. Sequencing batch anaerobic phosphorus release tank; 3. Phosphorus recovery reaction tank; 4. Sludge hopper; 5. Mud discharge pipe; 6. Sludge chain; 7. Primary sedimentation tank water inlet; 8. Primary sedimentation tank return port; 9. Phosphorus release water inlet; 10. Decanter; 11. Agitator; 12. Phosphorus release tank mud outlet; 13. Supernatant inlet; 14. Phosphorus-rich product discharge pipe; 15. First feed pipe; 16. Second feed pipe; 17. Fixed cylinder; 18. Filter cylinder; 19. Fixed plate; 20. Dropping port; 21. Reciprocating screw; 22. Second rotating motor; 23. Connecting seat; 24. Filter element; 25. Stirring bar; 26. Rotating ring; 27. Opening and closing plate; 28. Connecting plate; 29. ​​Limiting groove; 30. Limiting column; 31. Extension rod; 32. Trigger block; 33. Moving sleeve; 34. First positioning rod; 35. First push block; 36. Second positioning rod; 37. Second push block; 38. Water outlet pipe. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0041] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0042] like Figures 1 to 11As shown, a multi-stage fermentation acid production pre-phosphorus recovery device comprises an aerated grit chamber, a fermentation primary sedimentation tank 1, a pre-sequential batch phosphorus removal system, a treatment and discharge system and a recovery system. The aerated grit chamber is connected to an external sewage pipe, the fermentation primary sedimentation tank 1 is arranged on one side of the aerated grit chamber, the pre-sequential batch phosphorus removal system is connected to the fermentation primary sedimentation tank 1, and the treatment and discharge system is connected to one side of the pre-sequential batch phosphorus removal system; the fermentation primary sedimentation tank 1 is used to mix sewage with return residual sludge, and convert macromolecular organic matter into volatile fatty acids through fermentation acid production, which is used for subsequent anaerobic phosphorus release and denitrification. Denitrification provides a carbon source; the pre-sequential batch phosphorus removal system includes at least two sets of alternatingly operated sequential batch anaerobic phosphorus release tanks 2, and the pre-sequential batch phosphorus removal system is used to separate and enrich the phosphorus-rich supernatant; the recovery system is connected to the anaerobic phosphorus release tank through a pipeline, and the recovery system includes a stirring module and a pH adjustment system. The recovery system is used to recover and reuse phosphorus resources; the treatment and discharge system includes an anoxic tank, an aerobic tank, a secondary sedimentation tank and a deep treatment tank in sequence. The anoxic tank, the aerobic tank, the secondary sedimentation tank and the deep treatment tank are all connected by pipelines, and one side of the anoxic tank is connected to the pre-sequential batch phosphorus removal system. The system is connected; a sludge treatment system and a sludge return pipe are also provided on one side of the secondary sedimentation tank. The sludge treatment system is used to transport a part of the residual sludge. One side of the sludge treatment system is also connected to one side of the fermentation primary sedimentation tank 1. Two interfaces are provided on the sludge return pipe, one of which is connected to the anoxic tank for returning 80% to 98.5% of the residual sludge in the secondary sedimentation tank, and the other interface is connected to the fermentation primary sedimentation tank 1 for returning 1.5% to 4% of the residual sludge in the secondary sedimentation tank. A digestate return pipe is also provided on one side of the aerobic tank. The other end of the chemical liquid return pipe is connected to the anoxic tank, wherein one end of the fermentation primary sedimentation tank 1 is provided with a primary sedimentation tank water inlet 7 and a primary sedimentation tank return port 8, and valves are provided on the primary sedimentation tank water inlet 7 and the primary sedimentation tank return port 8, the primary sedimentation tank water inlet 7 is connected to the aerated grit chamber for sewage entry, the primary sedimentation tank return port 8 is connected to the sludge return pipe for sludge return, a sludge hopper 4 is provided at the bottom of the fermentation primary sedimentation tank 1, a sludge discharge pipe 5 is provided at the bottom of the sludge hopper 4, a sludge chain 6 is provided on one side of the fermentation primary sedimentation tank 1, and the sludge discharge pipe 5 is connected to the sludge treatment system;

[0043] After the floating objects and sand particles are removed from the sewage through the aerated grit chamber, it enters the fermentation primary sedimentation tank 1. The fermentation primary sedimentation tank 1 mixes the sewage with the 1.5%-4% residual sludge to ferment and produce acid, converting the macromolecular organic matter into volatile fatty acids. The mud-water mixture produced enters the pre-sequencing batch phosphorus removal system. The sequencing batch anaerobic phosphorus release tank 2 operates alternately through five stages: water inlet, reaction, sedimentation, decanting and sludge discharge. The phosphorus-rich supernatant is transmitted to the recovery system. The phosphorus-rich supernatant reacts with the chemical precipitant in the recovery system to generate struvite and is collected. The remaining sludge enters the subsequent treatment unit through the sludge discharge pipe. At the same time, part of the mud-water mixture enters the anoxic tank, and after denitrification treatment, it enters the aerobic tank for organic matter degradation. The nitrogen-rich digestate produced is returned to the anoxic tank through the digestate return pipe, further improving the denitrification efficiency. The effluent from the aerobic tank passes through the secondary sedimentation tank and the deep The treatment pool meets the discharge standards, and the residual sludge in the secondary sedimentation tank is divided into two parts for return. Among them, 80%-98.5% is returned to the anoxic tank to maintain the denitrification function, and 1.5%-4% is returned to the fermentation primary sedimentation tank 1 to provide fermentation substrate. The remaining residual sludge is transported out by the sludge treatment system. Among them, the fermentation primary sedimentation tank 1 converts the difficult-to-degrade macromolecular organic matter into volatile fatty acids (VFAs) through mixed fermentation of sewage and returned residual sludge, providing high-quality carbon source for subsequent anaerobic phosphorus release and denitrification denitrification, reducing the demand for external carbon source and reducing operating costs. The pre-sequential batch phosphorus removal system uses the alternating anaerobic phosphorus release tank to separate and enrich the phosphorus-rich supernatant, improve the phosphorus removal efficiency, and facilitate subsequent recovery. The sludge return pipe returns sludge to the anoxic tank and the fermentation primary sedimentation tank 1 through two interfaces respectively, realizing efficient allocation and utilization of sludge resources and maintaining stable operation of the system.

[0044] like Figure 1 , Figure 2 As shown, the hydraulic retention time of the fermentation primary sedimentation tank 1 is 2 to 3 hours, the sludge concentration at the bottom of the fermentation primary sedimentation tank 1 is set to be maintained at 7000 to 8000 mg / L, and the effluent mixed liquor concentration of the fermentation primary sedimentation tank 1 is set to be 2000 to 3000 mg / L;

[0045] Setting the hydraulic retention time of the primary fermentation sedimentation tank 1 to 2 to 3 hours can provide sufficient mixing and fermentation time for sewage and return sludge, avoid organic matter degradation loss caused by long fermentation while producing acid efficiently, increase the yield of volatile fatty acids (VFAs), and maximize the carbon source utilization efficiency. The sludge concentration at the bottom of the tank is set to 7000 to 8000 mg / L, which is conducive to maintaining a high activated sludge load, enhancing the processing capacity of the primary fermentation sedimentation tank 1 for organic matter, and avoiding the decrease in fermentation efficiency caused by too low sludge concentration. The effluent mixed liquor concentration is controlled at 2000 to 3000 mg / L, which not only ensures that the effluent rich in small molecular organic matter can meet the carbon source requirements of subsequent anaerobic phosphorus release and denitrification, but also reduces the impact of large particle suspended matter on subsequent treatment units, improves the stability and efficiency of system operation, and reduces unnecessary stirring and excessive sludge processing requirements by reasonably controlling the hydraulic retention time and sludge concentration, thereby reducing energy consumption and reducing the sludge load of subsequent systems.

[0046] like Figure 1 , Figure 3 , Figure 4 As shown, the sequencing batch anaerobic phosphate release tank 2 is arranged in a circular shape, a phosphorus release water inlet 9 is arranged on the upper side of the sequencing batch anaerobic phosphate release tank 2, a phosphorus release tank mud outlet 12 is arranged on the lower side of the sequencing batch anaerobic phosphate release tank 2, a decanter 10 and an agitator 11 are arranged inside the sequencing batch anaerobic phosphate release tank 2, the internal dissolved oxygen concentration in the sequencing batch anaerobic phosphate release tank 2 is kept below 0.5 mg / L, and the hydraulic retention time is 3 to 4 hours, the supernatant in the sequencing batch anaerobic phosphate release tank 2 is separated from the sludge by the decanter 10, a sludge layer sensor is arranged inside the decanter 10, and the lowest water level of the decanting water is at least 0.5 meters from the upper surface of the sludge layer, Used to prevent water pollution, the recovery system includes a phosphorus recovery reaction tank 3 connected to two sequencing batch anaerobic phosphorus release tanks 2, a supernatant inlet 13 is provided on one side of the phosphorus recovery reaction tank 3, the supernatant inlet 13 is used to add supernatant, a first feed pipe 15 and a second feed pipe 16 are respectively provided on both sides of the top of the phosphorus recovery reaction tank 3, a phosphorus-rich product discharge pipe 14 is provided at the bottom of the phosphorus recovery reaction tank 3, the first feed pipe 15 is used to place a phosphorus recovery chemical precipitant, the second feed pipe 16 is connected to the sequencing batch anaerobic phosphorus release tank 2, and the second feed pipe 16 is used to place the phosphorus-rich supernatant inside the sequencing batch anaerobic phosphorus release tank 2;

[0047] The muddy water mixture produced after the sewage and the return sludge are fermented in the primary fermentation settling tank 1 enters the sequencing batch anaerobic phosphorus release tank 2 through the phosphorus release water inlet 9. The muddy water in the sequencing batch anaerobic phosphorus release tank 2 is kept fully mixed by the agitator 11, and the dissolved oxygen concentration is controlled to be lower than 0.5 mg / L. The hydraulic retention time is 3 to 4 hours, so that the polyphosphate bacteria release the stored phosphate into the supernatant. The supernatant is separated by the decanter 10 and then flows into the phosphorus recovery reaction tank 3 through the second feed pipe 16. The sludge layer sensor of the decanter 10 confirms The lowest water level of the decanting water is kept at a distance of more than 0.5 meters from the upper surface of the sludge layer to avoid water pollution. After the phosphorus-rich supernatant enters the phosphorus recovery reaction tank 3, a chemical precipitant is added through the first feed pipe 15. The phosphorus-rich supernatant and the chemical precipitant fully react to form struvite. The phosphorus-rich product is discharged through the phosphorus-rich product discharge pipe 14 at the bottom. The remaining sludge in the phosphorus release tank is discharged to the subsequent treatment unit through the phosphorus release tank mud outlet 12. The sequencing batch anaerobic phosphorus release tank 2 is operated alternately to ensure the continuous separation and transportation of the phosphorus-rich supernatant;

[0048] A pH detection and adjustment system is also provided on one side of the phosphorus recovery reaction tank 3. When the pH inside the phosphorus recovery reaction tank 3 is lower than 8.5, the pH adjustment system automatically adds an alkaline regulator until the pH reaches 10;

[0049] The phosphorus-rich supernatant enters the phosphorus recovery reaction tank 3 through the second feed pipe 16, and at the same time, a chemical precipitant is added through the first feed pipe 15. The pH detection and adjustment system in the tank monitors the pH of the reaction tank in real time. When the pH value is lower than 8.5, the pH adjustment system automatically adds an alkaline adjustment agent (such as sodium hydroxide solution or sodium carbonate solution) to adjust the reaction environment to about pH 10 to ensure that phosphates and magnesium ions react fully to form struvite. After the adjustment is completed, the struvite in the phosphorus recovery reaction tank 3 is discharged through the phosphorus-rich product discharge pipe 14 at the bottom to ensure the continuous operation of the reaction tank and efficient phosphorus recovery;

[0050] The chemical precipitant placed inside the phosphorus recovery reaction tank 3 is magnesium salt, which can react to generate magnesium ammonium phosphate hexahydrate, and the optimal reaction conditions are pH 8.5 to 10, wherein the Mg / P ratio is 1.5:1, and the phosphorus recovery rate can reach 85%;

[0051] The phosphorus-rich supernatant enters the phosphorus recovery reaction tank 3 through the second feed pipe 16, and at the same time, a chemical precipitant (magnesium salt) is added through the first feed pipe 15 to perform a precipitation reaction inside the phosphorus recovery reaction tank 3. The specific reaction is as follows:

[0052] Mg2++NH4++PO43-+6H2O→MgNH4PO46H2O

[0053] The magnesium ammonium phosphate hexahydrate (struvite) generated by the reaction is a highly efficient slow-release fertilizer that can be directly used for agricultural purposes. The optimal conditions for the reaction are: the pH value is controlled at 8.5 to 10 (achieved by a pH adjustment system), and the Mg / P ratio is 1.5:1. Under this condition, magnesium ions react fully with phosphate ions and ammonium ions, and the phosphorus recovery rate can reach 85%. The struvite generated by the reaction is discharged through the phosphorus-rich product discharge pipe 14 for further processing or direct application. At the same time, the reaction tank maintains continuous operation to ensure the simultaneous removal of nitrogen and phosphorus in the wastewater.

[0054] like Figures 6 to 11 As shown, a fixed cylinder 17 is fixedly installed at the top of the phosphorus recovery reaction pool 3, a filter cartridge 18 is rotatably installed below the fixed cylinder 17, a bearing is provided between the fixed cylinder 17 and the filter cartridge 18, a reciprocating screw rod 21 is rotatably installed in the middle of the inner part of the separation cylinder, a second rotating motor 22 is fixedly installed at the middle of the top of the separation cylinder, an output end of the second rotating motor 22 is fixedly connected to the reciprocating screw rod 21, a connecting seat 23 is fixedly sleeved on one side of the reciprocating screw rod 21, and the connecting seat 23 is fixedly connected to the filter cartridge 18 The filter cartridge 18 is provided with a filter element 24 inside, and a spiral stirring bar 25 is also provided inside the filter cartridge 18. The bottom end of the stirring bar 25 is fixedly connected to the connecting seat 23. A fixed plate 19 is fixedly installed at the bottom of the phosphorus recovery reaction tank 3. A rotating ring 26 is rotatably installed above the fixed plate 19. A drop-out port 20 is opened in the middle of the fixed plate 19. The drop-out port 20 is connected to the phosphorus-rich product discharge pipe 14. A plurality of opening and closing plates 27 are rotatably installed on the inner side of the top of the drop-out port 20. One side of the rotating ring 26 is provided with a plurality of opening and closing plates 27. A plurality of connecting plates 28 are rotatably installed on the side, and the plurality of connecting plates 28 are rotatably connected to one side of the opening and closing plate 27. When the plurality of opening and closing plates 27 are close to each other, the material drop opening 20 is closed, and when the plurality of opening and closing plates 27 are away from each other, the material drop opening 20 is opened. A plurality of limiting grooves 29 are equidistantly provided on the outer periphery of the rotating ring 26, and a plurality of limiting columns 30 slidably installed in the limiting grooves 29 are provided on the top of the fixed plate 19. An extension rod 31 is provided on one side of the top surface of the rotating ring 26, and a trigger block 3 is provided on the top of the extension rod 31. 2, the outer surface of the reciprocating screw rod 21 is threadedly connected with a moving sleeve 33, and the first positioning rod 34 and the second positioning rod 36 are respectively arranged on both sides of the moving sleeve 33, and the bottom ends of the first positioning rod 34 and the second positioning rod 36 are respectively provided with a first push block 35 and a second push block 37, the height of the first push block 35 is higher than the height of the second push block 37, the bottom surface of the first push block 35 is an inclined surface, and the top surface of the second push block 37 is an inclined surface, wherein a water outlet pipe 38 is also arranged on one side of the bottom of the phosphorus recovery reaction tank 3;

[0055] In the phosphorus recovery reaction tank 3, the phosphorus-rich supernatant enters the filter cartridge 18 through the feed pipe, and the chemical precipitant also enters the filter cartridge 18, and is fully mixed and reacted with the chemical precipitant under the action of the spiral stirring bar 25 to generate struvite particles. The fixed cylinder 17 supports the filter cartridge 18 through the bearing, and the filter element 24 is used for solid-liquid separation. The filtered clear liquid is discharged, and the struvite particles are deposited at the bottom of the filter cartridge 18. The second rotating motor 22 is started, and the reciprocating screw rod 21 drives the movable sleeve 33 to move up and down. The movable sleeve 33 carries the first positioning rod 34 and the second positioning rod 36, which push the first push block 35 and the second push block 37 and the extension rod 31 in turn. The first push block 35 is higher and first drives the extension rod 31 through its inclined surface to rotate the rotating ring 26. The connecting plate 28 pulls the opening and closing plate 27 away, the drop port 20 opens, and the struvite is discharged from the drop port 20 to the phosphorus-rich product discharge pipe 14. When the movable sleeve 33 returns, the second push block 37 gradually resets the extension rod 31 through its inclined surface to close the drop port 20, completing a drop process, ensuring the automatic discharge of struvite and the continuous operation of the equipment. The filter cartridge 18 is installed below the fixed cartridge 17 through a bearing, and the internal filter element 24 realizes solid-liquid separation, and the clear liquid is discharged through the outlet pipe 38 at the bottom.

[0056] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0057] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-stage fermentation acid production pre-phosphorus recovery device, comprising an aerated grit chamber, a fermentation primary sedimentation tank (1), a pre-sequential batch phosphorus removal system, a treatment and discharge system and a recovery system, characterized in that: The aerated grit chamber is connected to an external sewage pipe, the fermentation primary sedimentation tank (1) is arranged on one side of the aerated grit chamber, the pre-sequential batch phosphorus removal system is connected to the fermentation primary sedimentation tank (1), and the treatment and discharge system is connected to one side of the pre-sequential batch phosphorus removal system; The fermentation primary sedimentation tank (1) is used to mix sewage with the returned excess sludge, and convert macromolecular organic matter into volatile fatty acids through fermentation and acid production, thereby providing a carbon source for subsequent anaerobic phosphorus release and denitrification; The pre-sequencing batch phosphorus removal system comprises at least two groups of sequencing batch anaerobic phosphorus release tanks (2) that operate alternately, and the pre-sequencing batch phosphorus removal system is used to separate and enrich the phosphorus-rich supernatant; The recovery system is connected to the anaerobic phosphorus release tank through a pipeline, and the recovery system includes a stirring module and a pH adjustment system, and the recovery system is used for recovering and reusing phosphorus resources; The treatment and discharge system includes an anoxic tank, an aerobic tank, a secondary sedimentation tank and a deep treatment tank in sequence, wherein the anoxic tank, the aerobic tank, the secondary sedimentation tank and the deep treatment tank are all connected through pipelines, and one side of the anoxic tank is connected to the pre-sequential batch phosphorus removal system; A sludge treatment system and a sludge return pipe are also provided on one side of the secondary sedimentation tank. The sludge treatment system is used to transport a part of the residual sludge. One side of the sludge treatment system is also connected to one side of the fermentation primary sedimentation tank (1). Two interfaces are provided on the sludge return pipe, one of which is connected to the anoxic tank for returning 80% to 98.5% of the residual sludge in the secondary sedimentation tank, and the other interface is connected to the fermentation primary sedimentation tank (1) for returning 1.5% to 4% of the residual sludge in the secondary sedimentation tank. A digestion liquid return pipe is also provided on one side of the aerobic tank, and the other end of the digestion liquid return pipe is connected to the anoxic tank.

2. The multi-stage fermentation acid production pre-phosphorus recovery device according to claim 1, characterized in that: A primary sedimentation tank water inlet (7) and a primary sedimentation tank return port (8) are provided at one end of the fermentation primary sedimentation tank (1), and valves are provided on the primary sedimentation tank water inlet (7) and the primary sedimentation tank return port (8). The primary sedimentation tank water inlet (7) is connected to the aerated grit chamber for sewage to enter, and the primary sedimentation tank return port (8) is connected to the sludge return pipe for sludge return. A sludge hopper (4) is provided at the bottom of the fermentation primary sedimentation tank (1), and a sludge discharge pipe (5) is provided at the bottom of the sludge hopper (4). A sludge chain (6) is provided on one side of the fermentation primary sedimentation tank (1), and the sludge discharge pipe (5) is connected to the sludge treatment system.

3. The multi-stage fermentation acid production pre-phosphorus recovery device according to claim 2, characterized in that: The hydraulic retention time of the primary fermentation sedimentation tank (1) is 2 to 3 hours, the sludge concentration at the bottom of the primary fermentation sedimentation tank (1) is set to be maintained at 7000 to 8000 mg / L, and the effluent mixed liquor concentration of the primary fermentation sedimentation tank (1) is set to be 2000 to 3000 mg / L.

4. The multi-stage fermentation acid production pre-phosphorus recovery device according to claim 1, characterized in that: The sequencing batch anaerobic phosphorus release tank (2) is arranged in a circular shape. A phosphorus release water inlet (9) is arranged on the upper side of the sequencing batch anaerobic phosphorus release tank (2). A phosphorus release tank sludge outlet (12) is arranged on the lower side of the sequencing batch anaerobic phosphorus release tank (2). A decanter (10) and a stirrer (11) are arranged inside the sequencing batch anaerobic phosphorus release tank (2). The internal dissolved oxygen concentration in the sequencing batch anaerobic phosphorus release tank (2) is kept below 0.5 mg / L, and the hydraulic retention time is 3 to 4 hours. The supernatant in the sequencing batch anaerobic phosphorus release tank (2) is separated from the sludge by the decanter (10). A sludge layer sensor is arranged inside the decanter (10). The lowest water level of the decanting water is at least 0.5 meters away from the upper surface of the sludge layer, so as to prevent water pollution.

5. The multi-stage fermentation acid production pre-phosphorus recovery device according to claim 1, characterized in that: The recovery system comprises a phosphorus recovery reaction tank (3) connected to the two sequencing batch anaerobic phosphorus release tanks (2); a supernatant inlet (13) is provided on one side of the phosphorus recovery reaction tank (3); the supernatant inlet (13) is used to add supernatant; a first feed pipe (15) and a second feed pipe (16) are provided on both sides of the top of the phosphorus recovery reaction tank (3); a phosphorus-rich product discharge pipe (14) is provided at the bottom of the phosphorus recovery reaction tank (3); the first feed pipe (15) is used to place a phosphorus recovery chemical precipitant; the second feed pipe (16) is connected to the sequencing batch anaerobic phosphorus release tank (2); the second feed pipe (16) is used to place phosphorus-rich supernatant in the sequencing batch anaerobic phosphorus release tank (2); and a water outlet pipe (38) is also provided on one side of the bottom of the phosphorus recovery reaction tank (3).

6. The multi-stage fermentation acid production pre-phosphorus recovery device according to claim 5, characterized in that: A pH detection and adjustment system is also provided on one side of the phosphorus recovery reaction tank (3). When the pH inside the phosphorus recovery reaction tank (3) is lower than 8.5, the pH adjustment system automatically adds an alkaline regulator until the pH reaches 10.

7. The multi-stage fermentation acid production pre-phosphorus recovery device according to claim 6, characterized in that: The chemical precipitant placed inside the phosphorus recovery reaction tank (3) is magnesium salt, which can react to generate magnesium ammonium phosphate hexahydrate, and the optimal reaction conditions are pH 8.5 to 10, wherein the Mg / P ratio is 1.5:1, and the phosphorus recovery rate can reach 85%.

8. The multi-stage fermentation acid production pre-phosphorus recovery device according to claim 7, characterized in that: A fixed cylinder (17) is fixedly installed at the top of the phosphorus recovery reaction pool (3), a filter cylinder (18) is rotatably installed below the fixed cylinder (17), a bearing is arranged between the fixed cylinder (17) and the filter cylinder (18), a reciprocating screw rod (21) is rotatably installed in the middle of the interior of the separation cylinder, a second rotating motor (22) is fixedly installed at the middle of the top of the separation cylinder, the output end of the second rotating motor (22) is fixedly connected to the reciprocating screw rod (21), a connecting seat (23) is fixedly sleeved on one side of the reciprocating screw rod (21), the connecting seat (23) is fixedly connected to the filter cylinder (18), a filter element (24) is arranged inside the filter cylinder (18), and a spiral stirring bar (25) is also arranged inside the filter cylinder (18), the bottom end of the stirring bar (25) is fixedly connected to the connecting seat (23).

9. The multi-stage fermentation acid production pre-phosphorus recovery device according to claim 8, characterized in that: A fixed plate (19) is fixedly installed at the bottom of the phosphorus recovery reaction pool (3), a rotating ring (26) is rotatably installed above the fixed plate (19), a drop opening (20) is opened in the middle of the fixed plate (19), the drop opening (20) is connected to the phosphorus-rich product discharge pipe (14), a plurality of opening and closing plates (27) are rotatably installed on the inner side of the top of the drop opening (20), a plurality of connecting plates (28) are rotatably installed on one side of the rotating ring (26), a plurality of connecting plates (28) are rotatably connected to one side of the opening and closing plate (27), the drop opening (20) is closed when the plurality of opening and closing plates (27) are close to each other, and the drop opening (20) is opened when the plurality of opening and closing plates (27) are away from each other, a plurality of limiting grooves (29) are equidistantly opened on the outer circumference of the rotating ring (26), and a plurality of limiting columns (30) slidably installed in the limiting grooves (29) are arranged on the top of the fixed plate (19).

10. The multi-stage fermentation acid production pre-phosphorus recovery device according to claim 9, characterized in that: An extension rod (31) is arranged on one side of the top surface of the rotating ring (26), a trigger block (32) is arranged on the top of the extension rod (31), a moving sleeve (33) is threadedly connected to the outer surface of the reciprocating screw rod (21), a first positioning rod (34) and a second positioning rod (36) are arranged on both sides of the moving sleeve (33), a first push block (35) and a second push block (37) are arranged at the bottom ends of the first positioning rod (34) and the second positioning rod (36), the height of the first push block (35) is higher than the height of the second push block (37), the bottom surface of the first push block (35) is an inclined surface, and the top surface of the second push block (37) is an inclined surface.

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