Wastewater treatment system and method

Abstract

The wastewater treatment system comprises a water inlet unit, a reactor, a separation unit and a circulation unit which are sequentially connected to form a closed-loop system, the water inlet unit is further connected with a chemical dosing unit, the water inlet unit is used for conveying wastewater to the reactor, and the chemical dosing unit is used for adding alkali into the wastewater to adjust the pH value and providing required magnesium ions; a fluidization reaction zone and a separation zone are arranged in the reactor, and the fluidization reaction zone promotes generation and growth of struvite particles through particle collision and aggregation; the separation zone enables generated particles to partially fall back to the fluidization reaction zone for continuous reaction through preliminary solid-liquid separation; the separation unit is used for receiving the wastewater in the separation area, further removing residual particles, and enabling the small particles to flow back to the reactor through the circulation unit for recycling. By optimizing particle generation, separation and backflow processes in wastewater treatment, formation of target large particles is promoted, resource recycling is facilitated, meanwhile, consumption of chemical agents is reduced, and cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment and relates to a wastewater treatment system and method. Background Art

[0002] In the fermentation wastewater treatment system mainly based on soybean protein wastewater, the nitrogen and phosphorus content is high. At present, chemical precipitation is often used, especially by adding alkali and magnesium salts and other agents to adjust the pH value and provide necessary metal ions (such as Mg 2+ ) to promote the reaction of nitrogen and phosphorus pollutants with other components to form struvite particles, and then remove pollutants in the wastewater through solid-liquid separation.

[0003] However, the existing chemical precipitation wastewater treatment technology has certain limitations in particle generation and size control. Due to the limitations of reaction conditions and mixing efficiency, the generated particles are often uneven in size, with low separation efficiency. In addition, due to the small size of the particles, it is not conducive to resource recycling, and there is also a risk of particle loss. In addition, the excessive use of chemical agents increases costs and may bring environmental burdens, and the lack of precision in automated control also affects the overall efficiency of the system.

[0004] To solve these problems, a more efficient and precise wastewater treatment system is needed that can achieve precise control of particles, reduce the consumption of chemical agents, and improve the level of automation. The system needs to optimize the particle return and separation process, reduce particle loss, and reduce operational complexity and energy consumption through a more intelligent control system, thereby improving treatment efficiency and economy. Summary of the invention

[0005] In order to solve the problems of low reaction efficiency, serious particle loss, high chemical agent consumption, and inaccurate automatic control in the prior art, the present invention provides a wastewater treatment system and method, which optimizes the particle generation, separation and reflux process in wastewater treatment, promotes the formation of target large particles, facilitates resource recycling, reduces the consumption of chemicals, reduces costs, and improves operation accuracy and stability through automatic control, ensuring treatment efficiency and continuous and stable operation of the system. It is particularly suitable for the treatment of wastewater with high pollution load, especially the treatment of wastewater containing nitrogen and phosphorus.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] According to a first aspect of the present invention, there is provided a wastewater treatment system, comprising a water inlet unit, a reactor, a separation unit and a circulation unit connected in sequence, wherein the water inlet unit is further connected to a dosing unit.

[0008] The water inlet unit is provided with a water inlet pipe connected to the reactor and used for conveying wastewater into the reactor;

[0009] The dosing unit includes a device for adding at least one agent to the wastewater to adjust the reaction conditions and promote particle generation;

[0010] The reactor is provided with a fluidized reaction zone and a separation zone. The fluidized reaction zone is used to promote the generation and growth of particles through collision and aggregation of particles; the separation zone is used to perform preliminary separation of the generated particles from the wastewater, and the separated particles fall back to the fluidized reaction zone to continue the reaction;

[0011] The separation unit is connected to the wastewater outlet of the separation zone through a first outlet pipe, and is used to receive the separated wastewater and further purify it; the separation unit is connected to the fluidized reaction zone through a second outlet pipe, and is used to receive the reaction mixture, filter and recover the target particles;

[0012] The circulation unit comprises a circulation pipe connected between the separation unit and the reactor, and is used for returning small particles in the separation unit that have not formed target particles to the reactor to continue to participate in the particle growth reaction.

[0013] In some technical solutions, the dosing unit is provided with an alkali dosing device connected to the water inlet pipe;

[0014] The circulation unit is provided with a pH measuring device, and the pH measuring device comprises:

[0015] A pH measuring tube, connected to the circulation tube, for diverting part of the circulating liquid;

[0016] pH measuring probe, installed in the pH measuring tube, used to detect the pH value of the circulating liquid;

[0017] The alkali dosing device automatically adjusts the addition rate and amount of the alkali according to the pH value detected by the pH measuring probe to maintain the pH value in the reactor within the target range.

[0018] In some technical solutions, the reactor is also equipped with a gas distribution device, which includes a fan and a gas distribution pipeline connected to the fan. The gas distribution pipeline is arranged below the fluidized reaction zone, and includes a gas distribution main pipe and several gas distribution branch pipes. The gas distribution branch pipes are evenly distributed on the cross-section of the reactor.

[0019] In some technical solutions, the water inlet unit further includes a water inlet pump and a water inlet flow meter, both of which are arranged on the water inlet pipe, and the flow setting value of the water inlet flow meter is linked with the PID control of the water inlet pump to adjust the water inlet flow and ensure the stability of the flow;

[0020] The circulation unit also includes a circulation pump and a circulation flow meter, both of which are arranged on the circulation pipe. The flow setting value of the circulation flow meter is linked with the PID control of the circulation pump to adjust the circulation flow and provide a stable rising flow rate for the reactor.

[0021] In some technical solutions, the water inlet unit is further equipped with a water distribution pipeline, which includes a water distribution main pipe and a plurality of water distribution branches, the water distribution main pipe is connected to the water outlet end of the water inlet pipe, and the water distribution branches are evenly distributed on the cross section of the reactor for evenly supplying wastewater into the reactor; and / or,

[0022] A liquid mixer is provided at the connection between the circulation pipe and the water inlet pipe, or the water outlet end of the circulation pipe is obliquely inserted into the center of the water inlet pipe.

[0023] In some technical solutions, the separation unit includes an inclined mesh separation device and a collection tank, wherein the inclined mesh separation device is used to separate target particles in the wastewater, and the separated target particles enter the collection tank through a collection pipe;

[0024] The collecting tank is connected to an external system through a discharge pipe, a discharge valve is provided on the discharge pipe, and the opening of the discharge valve is automatically controlled by a liquid level meter, which automatically adjusts the opening of the discharge valve according to the level change of the collecting tank.

[0025] In some technical solutions, the circulation unit further includes a circulation tank, and the circulation tank receives the wastewater separated by the inclined mesh separation device through a clean water pipe;

[0026] The collection tank is provided with a drain pipe, which is a small-diameter pipe capable of automatic drainage;

[0027] An overflow pipe is provided between the collection tank and the circulation tank. When the water volume is too large, the sewage flows into the circulation tank through the overflow pipe.

[0028] The clean water outlet of the circulation tank is connected to the main water outlet pipe, and the sewage outlet is connected to the circulation pipe for backflow to the reactor.

[0029] In some technical solutions, the reactor is also equipped with a sampling device for collecting mixed liquids at different heights in the reactor to observe and analyze the particle morphology. When it is observed that the particles meet the emission standards, the sampling device controls the second water outlet pipe through a switch valve to discharge the mixed liquid rich in target particles.

[0030] In some technical solutions, the separation zone is provided with a separation module, which includes multiple components working together to perform solid-liquid separation:

[0031] The water inlet channel and the water inlet hole are used to introduce the sewage mixture into the separation module;

[0032] The inclined plate is used for solid-liquid separation, and the separated particles enter the collection tank through the mud slide and the collection hole;

[0033] The collecting tank is provided with a slope, by means of which the particles are guided back to the fluidized reaction zone to continue to participate in the reaction;

[0034] The outlet branch trough and the outlet main trough are used to receive the purified sewage, which enters the outlet main trough through a drop method, and is finally discharged from the reactor through the first outlet pipe.

[0035] According to another aspect of the present invention, there is further provided a wastewater treatment method, comprising the following steps:

[0036] The wastewater rich in nitrogen and phosphorus is transported to the reactor through the water inlet pump and evenly distributed in the reactor through the water distribution pipeline. The water inlet flow rate is monitored and adjusted in real time through the water inlet flow meter;

[0037] The pH value in the reactor is controlled to be above 9 by using an alkali dosing device, and the magnesium salt dosing device provides the required magnesium ions for the reaction to promote the formation of struvite particles;

[0038] In the reactor, the particles are mixed and collided through the fluidized bed to form target particles. At the same time, solid-liquid separation is performed in the separation module. The separated struvite particles are returned to the fluidized bed. The purified sewage enters the inclined screen separation device through the first outlet pipe. The small particles that have not formed the target particles enter the circulation tank through the clean water pipe and are sent back to the reactor through the circulation pump and the circulation pipe. The circulation flow meter is used to monitor the circulation flow in real time.

[0039] The struvite mixed liquid at different heights in the reactor is observed and detected by a sampling device. When the particles meet the discharge requirements, the switch valve on the second outlet pipe is opened to discharge the mixed liquid rich in struvite particles. Under the action of the inclined mesh separation device, large particles of struvite enter the collection tank through the collection pipe and are discharged and recovered through the discharge pipe.

[0040] The present invention adopts the above technical solution to have at least the following beneficial effects:

[0041] 1. The present invention achieves efficient removal of nitrogen and phosphorus pollutants in wastewater through the synergistic effect of the optimized designed water inlet unit, reactor, separation unit and circulation unit. The fluidized reaction zone promotes the generation and growth of target particles (struvite) through the collision and aggregation of particles, the separation unit fully recovers the target particles, and the circulation unit ensures the reflux utilization of particles that are not fully reacted. The overall system significantly improves the reaction efficiency, reduces particle loss, and reduces the use of chemical agents, providing an economical and efficient solution for the treatment of high-pollution-load wastewater.

[0042] 2. The present invention ensures the best alkaline environment (pH ≥ 9) for the struvite formation reaction in wastewater through real-time linkage control of the alkali dosing device and the pH measuring device. This automated control method reduces unnecessary chemical agent consumption, reduces operating costs, and improves the stability of the reaction and the quality of the generated particles, which helps to achieve resource recycling.

[0043] 3. The uniformly distributed gas in the gas distribution device of the present invention not only improves the exchange efficiency of dissolved gas in the reactor, but also reduces the dosage of alkali by removing dissolved CO2. The synergistic effect of gas distribution and water distribution further enhances the suspension state and fluidization effect of particles, avoids particle deposition, and significantly improves the efficiency and uniformity of particle growth.

[0044] 4. The PID linkage control of the water inlet pump and the circulation pump of the present invention significantly improves the automation of the system. The precisely adjusted water inlet flow and circulation flow ensure stable reaction conditions in the fluidized bed, provide a stable power basis for the formation of large-particle struvite, and reduce the operational complexity and the influence of human errors.

[0045] 5. The sampling device of the present invention can monitor the state of particles in the reactor in real time, and timely adjust the reaction conditions by observing and analyzing the size and shape of the particles. When the particles meet the discharge requirements, the mixed liquid can be accurately discharged through automatic control, which improves the flexibility and processing efficiency of the system operation.

[0046] 6. The multi-component collaborative design of the separation module of the present invention optimizes the efficiency of solid-liquid separation. Through the reasonable division of labor of the inlet channel, inclined plate, mud slide and other structures, not only the efficient separation and reflux of particles are achieved, but also the waste of resources is avoided, providing a stable guarantee for the recycling and further growth of particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings and their marks required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0048] Figure 1 It is a schematic diagram of the overall structure of a wastewater treatment system in one embodiment of the present invention;

[0049] Figure 2 It is a schematic diagram of the top view of the structure of the air and water distribution device in one embodiment of the present invention;

[0050] Figure 3 It is a side view structural schematic diagram of an air distribution and water distribution device in one embodiment of the present invention;

[0051] Figure 4 This is a schematic diagram of the structure in which a circulation pipe is connected to a water inlet pipe in one embodiment of the present invention;

[0052] Figure 5 It is a schematic diagram of the top view of the separation module in one embodiment of the present invention;

[0053] Figure 6 for Figure 5 A schematic cross-sectional view of the structure of Figure 1-1;

[0054] Figure 7 for Figure 5 Schematic diagram of the cross-sectional structure of 2-2.

[0055] The meanings of the symbols in the figure are as follows:

[0056] 1. Water inlet pump; 2. Water inlet flowmeter; 3. Water inlet pipe; 4. Alkali dosing device; 5. Magnesium salt dosing device; 6. Water distribution pipeline; 7. Sampling device; 8. Reactor; 9. Fluidized bed; 10. Separation module; 12. First water outlet pipe; 13. Second water outlet pipe; 14. Switch valve; 15. Inclined net separation device; 16. Collection pipe; 17. Clean water pipe; 18. Main water outlet pipe; 19. Collection tank; 20. Circulation tank; 21. pH measuring probe; 22. pH measuring tube; 23. Circulation pump; 24. Circulation pipe; 25. Circulation flowmeter; 26. Discharge pipe; 27. Overflow pipe; 28. Discharge valve; 29. ​​Fan; 30. Air distribution device; 31. Liquid level meter; 32. Spray pipe; 33. Drain pipe;

[0057] 301, gas distribution main pipe; 302, gas distribution branch pipe; 601, water distribution main pipe; 602, water distribution branch pipe;

[0058] 101. Water inlet channel; 102. Water inlet hole; 103. Water outlet branch trough; 104. Water outlet main trough; 105. Water outlet main trough; 106. Mud slide; 107. Collecting trough; 108. Collecting hole; 109. Inclined plate. DETAILED DESCRIPTION

[0059] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0060] In order to simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0061] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0062] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0064] like Figure 1 According to an embodiment of the present invention, the wastewater treatment system comprises a water inlet unit, a reactor 8, a separation unit and a circulation unit. These modules are connected in sequence according to the process sequence to form a closed-loop system. The water inlet unit is also connected to a dosing unit, wherein the water inlet unit is used to transport the wastewater to the reactor 8, and the dosing unit is used to add alkali to the wastewater to adjust the pH value and provide the required magnesium ions; a fluidized reaction zone and a separation zone are provided inside the reactor 8, and the fluidized reaction zone promotes the formation and growth of struvite particles through particle collision and aggregation; the separation zone returns part of the generated particles to the fluidized reaction zone for further reaction through preliminary solid-liquid separation; the separation unit is used to receive the wastewater from the separation zone, further remove residual particles, and return the small particles to the reactor 8 through the circulation unit for reuse.

[0065] This embodiment achieves efficient removal and resource utilization of nitrogen and phosphorus pollutants by optimizing the wastewater treatment process. The system uses the fluidization reaction of particles to promote the formation and growth of struvite, and reduces particle loss through a circulation mechanism, thereby improving resource utilization. This design significantly improves wastewater treatment efficiency and reduces operating costs, and is particularly suitable for efficient treatment of high-pollution-load wastewater.

[0066] In a preferred embodiment, the dosing unit includes an alkali dosing device 4 and a magnesium salt dosing device 5, both of which are arranged on the water inlet pipe 3 of the water inlet unit, and the circulation unit includes a circulation pipe 24, and a pH measuring device is arranged on the circulation pipe 24. Specifically, the pH measuring device includes a pH measuring pipe 22, which is connected to the circulation pipe 24 and is used to divert part of the circulating liquid; a pH measuring probe 21, which is installed in the pH measuring pipe 22 and is used to detect the pH value of the circulating liquid; a signal processing module, which is connected to the pH measuring probe 21 and is used to receive and process the pH detection signal; a control module, which is connected to the alkali dosing device 4 and is used to adjust the amount of alkali added according to the processed signal; the alkali dosing device 4 automatically adjusts the addition rate and amount of alkali according to the control signal of the pH measuring device, so that the pH value in the reactor 8 is always maintained in the optimal range (≥9) for the formation of struvite, thereby optimizing the formation conditions of particles.

[0067] This embodiment significantly improves the accuracy and efficiency of wastewater treatment by combining a dosing unit with a pH measuring device. The pH value of the circulating water is monitored in real time, and the dosage of alkali and magnesium salt is dynamically adjusted to ensure that the reaction conditions are always in the optimal range for struvite formation (pH ≥ 9). This optimized design reduces the excessive use of reagents, reduces operating costs, and improves the generation efficiency and quality of struvite particles. In addition, the automated dosing control system greatly reduces the impact of human intervention on reaction stability, making the entire wastewater treatment process more efficient and controllable, and further enhancing the economy and environmental benefits of the system.

[0068] More preferably, a circulation pump 23 and a circulation flow meter 25 are provided on the circulation pipe 24, and the flow setting value of the circulation flow meter 25 is linked with the PID control of the circulation pump 23, so as to adjust the circulation flow and provide a stable rising flow rate for the reactor 8; and an inlet pump 1 and an inlet flow meter 2 are provided on the inlet pipe 3, and the flow setting value of the inlet flow meter 2 is linked with the PID control of the inlet pump 1, so as to adjust the inlet flow and ensure the stability of the flow.

[0069] In this embodiment, by introducing a flow automatic control scheme, the precise flow regulation of the circulation pipe 24 and the water inlet pipe 3 is incorporated into the automatic control system, thereby achieving efficient operation and resource optimization of wastewater treatment. The water inlet pipe 3 and the circulation pipe 24 are equipped with a flow meter and a variable frequency pump respectively. The flow meter monitors the flow change in real time, and dynamically adjusts the operating frequency of the pump through the PID linkage control system to ensure the optimal ratio of the water inlet flow rate to the circulation flow rate. The optimization of the circulation flow rate not only maintains the stable fluidization conditions in the reactor 8, but also effectively reduces the dosage of the alkaline reagent by reflux of the high pH circulating liquid, while the stable water inlet flow rate ensures the balance of the processing capacity of the reactor 8. This scheme has significant effects in reducing the consumption of reagents, improving the efficiency of particle generation, and improving the stability of the system, further reducing the operating cost and complexity of the wastewater treatment process.

[0070] According to this embodiment, a liquid mixer is provided at the connection between the circulation pipe 24 and the water inlet pipe 3, or Figure 4 The outlet end of the circulation pipe 24 is obliquely inserted into the center of the water inlet pipe 3. The circulating water and the incoming water can be fully mixed to avoid the phenomenon that the incoming water only goes to some branches, resulting in uneven nutrition of the fluidized bed 9, that is, uneven reaction.

[0071] In another preferred embodiment, in conjunction with reference to Figure 2 and Figure 3 The bottom of the reactor 8 is equipped with an air distribution device 30, which includes an air distribution main pipe 301 and a plurality of air distribution branches 302, which are evenly distributed at the bottom of the reactor 8, and provide airflow through the fan 29 to remove dissolved CO2 in the wastewater and enhance the driving force. The air distribution device 30 of this solution provides airflow through the evenly distributed air distribution branches 302, which not only removes dissolved CO2 in the wastewater, increases the pH value, reduces the use of alkaline reagents, but also enhances the driving force in the reactor to prevent particle deposition.

[0072] According to this embodiment, in combination with reference to Figure 2 and Figure 3 The water inlet unit is also equipped with a water distribution pipeline 6, which includes a water distribution main pipe 601 and several water distribution branches 602. The water distribution main pipe 601 is connected to the water outlet end of the water inlet pipe 3, and the gas distribution branch pipe 302 is evenly distributed on the cross section of the reactor 8, which is used to evenly supply wastewater to the reactor 8. In this scheme, the water flow of the water distribution branch pipe 602 impacts the bottom of the reactor 8 downward to avoid particle deposition and enhance the fluidization effect; water is evenly supplied to the reactor 8 through the evenly distributed water distribution branch pipes 602 to ensure sufficient contact and reaction between the wastewater and the particles. At the same time, the synergistic effect of gas and liquid further optimizes the fluidization conditions, promotes the growth and suspension state of struvite particles, improves the generation efficiency and quality of particles, and effectively reduces resource waste, which significantly improves the efficiency and economy of wastewater treatment as a whole.

[0073] In a specific embodiment, if Figure 5-7 The separation zone is provided with a separation module 10, which includes multiple components working together to separate solid and liquid: the water inlet channel 101 and the water inlet hole 102 are used to introduce the sewage mixture into the separation module 10; the inclined plate 109 is used to separate solid and liquid, and the separated particles enter the collecting tank 107 through the mud slide 106 and the collecting hole 108; the collecting tank 107 is provided with a slope, and with the help of the slope, the particles are guided back to the fluidized reaction zone to continue to participate in the reaction; the outlet branch tank 103 and the outlet main tank 104 are used to receive the purified sewage, which enters the outlet main tank 105 by falling, and finally discharges from the reactor 8 through the first outlet pipe 12.

[0074] In this embodiment, the separation module 10 realizes efficient solid-liquid separation of particles in wastewater. The inclined plate structure increases the particle settling area, and the mud slide 106 guides the deposited particles into the collection tank 107 to achieve rapid recovery and recycling; at the same time, the purified wastewater is discharged through the outlet main tank 105, and the particle content is significantly reduced, meeting the discharge requirements.

[0075] In another specific embodiment, the water outlet of the separation module 10 is connected to the separation unit through the first outlet pipe 12, and the fluidized reaction zone is connected to the separation unit through the second outlet pipe 13. The separation unit includes an inclined mesh separation device 15 and a collection tank 19. The inclined mesh separation device 15 is connected to the first outlet pipe 12, and is used to receive the wastewater after preliminary separation for further purification; the inclined mesh separation device 15 is connected to the second outlet pipe 13, and is used to receive the reaction mixture, filter and recover the target particles; the target particles separated by the inclined mesh separation device 15 are sprayed into the collection pipe 16 by the spray pipe 32 and finally enter the collection tank 19. The collection tank 19 is connected to the external system through the discharge pipe 26, and the discharge pipe 26 is provided with a discharge valve 28. The opening of the discharge valve 28 is automatically controlled by the liquid level meter 31. The liquid level meter 31 automatically adjusts the opening of the discharge valve 28 according to the level change of the collection tank 19, thereby realizing the resource recycling of the struvite particles.

[0076] According to this embodiment, the circulation unit also includes a circulation tank 20, which receives the wastewater separated by the inclined mesh separation device 15 through the clean water pipe 17; the collection tank 19 is provided with a drain pipe 33, which is a small-diameter pipe and can drain water automatically; an overflow pipe 27 is provided between the collection tank 19 and the circulation tank 20. When the water volume is too large, the sewage flows into the circulation tank 20 through the overflow pipe 27 to prevent the sewage from overflowing to the ground and polluting the environment; the clean water outlet of the circulation tank 20 is connected to the main outlet pipe 18, and the sewage outlet is connected to the circulation pipe 24 for reflux to the reactor 8.

[0077] In another preferred embodiment, the reactor 8 is further equipped with a sampling device 7 for collecting mixed liquid at different heights in the reactor 8 for observation and analysis of particle morphology. When it is observed that the particles meet the emission standards, the sampling device 7 controls the second water outlet pipe 13 through the switch valve 14 to discharge the mixed liquid rich in target particles.

[0078] According to another embodiment of the present invention, there is provided a wastewater treatment method, comprising the following steps:

[0079] The wastewater rich in nitrogen and phosphorus is transported to the reactor 8 through the water inlet pump 1 and evenly distributed in the reactor 8 through the water distribution pipeline 6. The water inlet flow rate is monitored and adjusted in real time through the water inlet flow meter 2;

[0080] The alkali dosing device 4 is used to control the pH value in the reactor 8 to be above 9, and the magnesium salt dosing device 5 provides the required magnesium ions for the reaction to promote the formation of struvite particles;

[0081] In the reactor 8, the particles are mixed and collided by the fluidized bed 9 to form target particles. At the same time, solid-liquid separation is performed in the separation module 10. The separated struvite particles are returned to the fluidized bed 9. The purified sewage enters the inclined screen separation device 15 through the first outlet pipe 12. The small particles that have not formed the target particles enter the circulation tank 20 through the clean water pipe 17 and are sent back to the reactor 8 through the circulation pump 23 and the circulation pipe 24. The circulation flow meter 25 is used to monitor the circulation flow in real time.

[0082] The struvite mixed liquid at different heights in the reactor 8 is observed by the sampling device 7 to observe the size and shape of the struvite particles. When the particles meet the discharge requirements, the switch valve 14 on the second outlet pipe 13 is opened to discharge the mixed liquid rich in struvite particles. Under the action of the inclined net separation device 15, the large particles of struvite enter the collection tank 19 through the collection pipe 16 and are discharged through the discharge pipe 26 for recycling.

[0083] The excess water in the collection tank 19 flows into the circulation tank 20 through the overflow pipe 27 and is pumped back to the reactor 8 to prevent sewage from overflowing onto the ground and polluting the environment. It should be noted that the drain pipe 33 of the collection tank 19 is a small-diameter pipe that can automatically discharge the water in the tank. Only when the amount of water is too large will it overflow into the circulation tank 20 through the overflow pipe 27.

[0084] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A wastewater treatment system, characterized in that: It includes a water inlet unit, a reactor, a separation unit and a circulation unit connected in sequence, wherein the water inlet unit is also connected to a dosing unit. The water inlet unit is provided with a water inlet pipe connected to the reactor and used for conveying wastewater into the reactor; The dosing unit includes a device for adding at least one agent to the wastewater to adjust the reaction conditions and promote particle generation; The reactor is provided with a fluidized reaction zone and a separation zone. The fluidized reaction zone is used to promote the generation and growth of particles through collision and aggregation of particles; the separation zone is used to perform preliminary separation of the generated particles from the wastewater, and the separated particles fall back to the fluidized reaction zone to continue the reaction; The separation unit is connected to the wastewater outlet of the separation zone through a first outlet pipe, and is used to receive the separated wastewater and further purify it; the separation unit is connected to the fluidized reaction zone through a second outlet pipe, and is used to receive the reaction mixture, filter and recover the target particles; The circulation unit comprises a circulation pipe connected between the separation unit and the reactor, and is used for returning small particles in the separation unit that have not formed target particles to the reactor to continue to participate in the particle growth reaction.

2. The wastewater treatment system according to claim 1, characterized in that: The dosing unit is provided with an alkali dosing device connected to the water inlet pipe; The circulation unit is provided with a pH measuring device, and the pH measuring device comprises: A pH measuring tube, connected to the circulation tube, for diverting part of the circulating liquid; pH measuring probe, installed in the pH measuring tube, used to detect the pH value of the circulating liquid; The alkali dosing device automatically adjusts the addition rate and amount of the alkali according to the pH value detected by the pH measuring probe to maintain the pH value in the reactor within the target range.

3. The wastewater treatment system according to claim 1, characterized in that: The reactor is also equipped with a gas distribution device, which includes a fan and a gas distribution pipeline connected to the fan. The gas distribution pipeline is arranged below the fluidized reaction zone and includes a gas distribution main pipe and a plurality of gas distribution branch pipes. The gas distribution branch pipes are evenly distributed on the cross section of the reactor.

4. The wastewater treatment system according to claim 1, characterized in that: The water inlet unit also includes a water inlet pump and a water inlet flow meter, both of which are arranged on the water inlet pipe. The flow setting value of the water inlet flow meter is linked with the PID control of the water inlet pump to adjust the water inlet flow and ensure the stability of the flow; The circulation unit also includes a circulation pump and a circulation flow meter, both of which are arranged on the circulation pipe. The flow setting value of the circulation flow meter is linked with the PID control of the circulation pump to adjust the circulation flow and provide a stable rising flow rate for the reactor.

5. The wastewater treatment system according to claim 1, characterized in that: The water inlet unit is also equipped with a water distribution pipeline, which includes a water distribution main pipe and a plurality of water distribution branches, the water distribution main pipe is connected to the water outlet end of the water inlet pipe, and the water distribution branches are evenly distributed on the cross section of the reactor for evenly supplying wastewater into the reactor; and / or, A liquid mixer is provided at the connection between the circulation pipe and the water inlet pipe, or the water outlet end of the circulation pipe is obliquely inserted into the center of the water inlet pipe.

6. The wastewater treatment system according to claim 1, characterized in that: The separation unit comprises an inclined mesh separation device and a collection tank, wherein the inclined mesh separation device is used to separate target particles in the wastewater, and the separated target particles enter the collection tank through a collection pipe; The collecting tank is connected to an external system through a discharge pipe, a discharge valve is provided on the discharge pipe, and the opening of the discharge valve is automatically controlled by a liquid level meter, which automatically adjusts the opening of the discharge valve according to the level change of the collecting tank.

7. The wastewater treatment system according to claim 6, characterized in that: The circulation unit further comprises a circulation tank, which receives the wastewater separated by the inclined mesh separation device through a clean water pipe; The collection tank is provided with a drain pipe, which is a small-diameter pipe capable of automatic drainage; An overflow pipe is provided between the collection tank and the circulation tank. When the water volume is too large, the sewage flows into the circulation tank through the overflow pipe. The clean water outlet of the circulation tank is connected to the main water outlet pipe, and the sewage outlet is connected to the circulation pipe for backflow to the reactor.

8. The wastewater treatment system according to claim 1, characterized in that: The reactor is also equipped with a sampling device for collecting mixed liquid at different heights in the reactor for observation and analysis of particle morphology. When it is observed that the particles meet the emission standards, the sampling device controls the second outlet pipe through a switch valve to discharge the mixed liquid rich in target particles.

9. The wastewater treatment system according to claim 1, characterized in that: The separation zone is provided with a separation module, which includes multiple components working together to perform solid-liquid separation: The water inlet channel and the water inlet hole are used to introduce the sewage mixture into the separation module; The inclined plate is used for solid-liquid separation, and the separated particles enter the collection tank through the mud slide and the collection hole; The collecting tank is provided with a slope, by means of which the particles are guided back to the fluidized reaction zone to continue to participate in the reaction; The outlet branch trough and the outlet main trough are used to receive the purified sewage, which enters the outlet main trough through a drop method, and is finally discharged from the reactor through the first outlet pipe.

10. A method for treating wastewater, characterized in that: The following steps are involved: The wastewater rich in nitrogen and phosphorus is transported to the reactor through the water inlet pump and evenly distributed in the reactor through the water distribution pipeline. The water inlet flow rate is monitored and adjusted in real time through the water inlet flow meter; The pH value in the reactor is controlled to be above 9 by using an alkali dosing device, and the magnesium salt dosing device provides the required magnesium ions for the reaction to promote the formation of struvite particles; In the reactor, the particles are mixed and collided through the fluidized bed to form target particles. At the same time, solid-liquid separation is performed in the separation module. The separated struvite particles are returned to the fluidized bed. The purified sewage enters the inclined screen separation device through the first outlet pipe. The small particles that have not formed the target particles enter the circulation tank through the clean water pipe and are sent back to the reactor through the circulation pump and the circulation pipe. The circulation flow meter is used to monitor the circulation flow in real time. The struvite mixed liquid at different heights in the reactor is observed and detected by a sampling device. When the particles meet the discharge requirements, the switch valve on the second outlet pipe is opened to discharge the mixed liquid rich in struvite particles. Under the action of the inclined mesh separation device, large particles of struvite enter the collection tank through the collection pipe and are discharged and recovered through the discharge pipe.

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