Wastewater treatment system and wastewater treatment method based on bardenpho process

Abstract

This invention relates to the field of wastewater treatment technology, providing a wastewater treatment system and method based on the Bardenpho process. The system includes a primary anoxic unit, a primary aerobic unit, a secondary anoxic unit, a secondary aerobic unit, and a three-phase separator. The three-phase separator is installed within the secondary reaction tank and sealed to the bottom of the tank. It is suitable for dividing the secondary reaction tank into a secondary anoxic unit and a secondary aerobic unit. The integrated tank structure saves floor space and elevation loss, facilitates the use of a high-efficiency recirculation device, reduces recirculation energy consumption, and significantly improves the deep denitrification efficiency of the reactor. The three-phase separator automatically returns the separated nitrified sludge to the end of the secondary aerobic unit, and then recirculates it to the primary aerobic unit for further biochemical reactions. This simplifies operation, facilitates maintenance and management, and reduces operating energy consumption.

Description

Technical Field

[0001] This invention relates to the technical field of wastewater treatment, and more particularly to a wastewater treatment system and method based on the Bardenpho process. Background Technology

[0002] With the rapid development of my country's economy and the rapid improvement of people's living standards, the discharge of ammonia nitrogen wastewater has also increased. For example, wastewater from industries such as coking, pharmaceuticals, fertilizers, and aquaculture contains high concentrations of ammonia nitrogen. Some high-ammonia nitrogen wastewater is also generated in daily life, such as wastewater from highway service areas.

[0003] It is generally believed that the Kjeldahl nitrogen removal rate of a single-stage ANO denitrification process is difficult to reach 90%. Therefore, in order to achieve a higher Kjeldahl nitrogen removal rate or obtain effluent with lower total nitrogen, the two-stage AO Bardenpho biological process is usually chosen, which can achieve a Kjeldahl nitrogen removal rate of over 90%.

[0004] In the traditional Bardenpho process, a significant elevation difference is required between the biological treatment unit and the secondary sedimentation tank unit. Furthermore, the recirculation ratio of the mixed liquor from the primary aerobic unit to the primary anoxic unit is typically controlled at around 400%. Therefore, it is generally believed that the total nitrogen removal rate from primary nitrification and denitrification is about 70%, with the remaining total nitrogen removed by denitrification in the secondary anoxic unit. This limits the total nitrogen removal rate to some extent. The reasons for this are twofold. Firstly, primary mixed liquor recirculation usually employs mechanical recirculation. Increasing the recirculation ratio leads to a sharp increase in recirculation energy consumption, which is disproportionate to the increased primary total nitrogen removal rate, making the improved removal rate uneconomical. Secondly, increasing the recirculation ratio causes more dissolved oxygen to be recirculated to the primary anoxic unit, consuming more carbon sources from the raw water, which is also uneconomical. Summary of the Invention

[0005] This invention provides a wastewater treatment system and method based on the Bardenpho process. It uses a three-phase separator to replace the secondary sedimentation tank and divides the secondary reaction tank into a secondary anoxic unit and a secondary aerobic unit through the three-phase separator. This achieves an integrated structure, reduces space occupation, lowers the elevation settings between stages, facilitates the use of efficient recirculation devices, and is conducive to a high proportion of recirculation.

[0006] This invention provides a wastewater treatment system based on the Bardenpho process, comprising: a primary anoxic unit, a primary aerobic unit, a secondary anoxic unit, a secondary aerobic unit, and a three-phase separator; the first end of the primary anoxic unit is connected to an inlet pipe; a first water passage or a first reflux device is provided between the first end of the primary aerobic unit and the end of the primary anoxic unit, and a first water passage or a first reflux device is provided between the end of the primary aerobic unit and the first end of the primary anoxic unit; the primary aerobic unit also contains a flow channel; The first end of the secondary anoxic unit is connected to the end of the primary aerobic unit through the flow channel. The first end of the secondary aerobic unit is connected to the end of the secondary anoxic unit. The end of the secondary aerobic unit is connected to the primary aerobic unit through a second reflux channel, and a second reflux device is provided in the second reflux channel. A three-phase separator is located between the secondary anoxic unit and the secondary aerobic unit. The three-phase separator is used to isolate the secondary anoxic unit from the secondary aerobic unit, and the inlet end of the three-phase separator is connected to the secondary aerobic unit. The three-phase separator comprises: a first plate, a second plate, and a third plate; the first plate is disposed between the secondary aerobic unit and the secondary anoxic unit, and one end of the first plate is sealed to the bottom surface of the secondary aerobic unit to isolate the secondary anoxic unit from the secondary aerobic unit through the first plate; the second plate is located inside the secondary aerobic unit and disposed on one side of the first plate, the second plate and a portion of the first plate forming a mud-water separation chamber, the bottom of the mud-water separation chamber forming a mud-water inlet, the top of the mud-water separation chamber forming a clear water outlet, the clear water outlet being provided with a water collection tank, the water collection tank being connected to a drainage pipe; the third plate is disposed on one side of the second plate, a portion of the third plate and a portion of the second plate forming a mixing channel, the remaining portion of the third plate, the remaining portion of the second plate, and the remaining portion of the first plate together forming a buffer chamber, the buffer chamber being located below the mud-water separation chamber, the mixing channel and the mud-water inlet being connected to the buffer chamber, and the bottom of the buffer chamber forming a mud-water outlet.

[0007] According to the wastewater treatment system based on the Bardenpho process provided by the present invention, a first guide plate is provided in the first-stage anoxic unit, a second guide plate is provided in the first-stage aerobic unit, and a third and a fourth guide plate are provided in the second-stage anoxic unit. The first, second, third, and fourth guide plates are all used to adjust the flow path within their respective treatment units.

[0008] In the wastewater treatment system based on the Bardenpho process provided by the present invention, both the first reflux device and the second reflux device are air-lift reflux devices.

[0009] According to the wastewater treatment system based on the Bardenpho process provided by the present invention, both the primary anoxic unit and the secondary anoxic unit are equipped with a stirring device.

[0010] According to the wastewater treatment system based on the Bardenpho process provided by the present invention, the bottom of the sludge-water separation chamber is connected to a sludge discharge pipe, and the bottom of the sludge-water separation chamber is constructed as a hopper-shaped structure; the middle part of the sludge-water separation chamber has a combined packing material, and the combined packing material is equipped with a cleaning component.

[0011] According to the wastewater treatment system based on the Bardenpho process provided by the present invention, the terminal of the primary aerobic unit is provided with a dissolved oxygen monitoring element and / or a redox potential monitoring element.

[0012] Another aspect of the present invention provides a wastewater treatment method using a wastewater treatment system based on the Bardenpho process described in any of the above claims, comprising: introducing wastewater into a primary anoxic unit; mixing the carbon source in the wastewater with primary nitrifying sludge returned from the end of a primary aerobic unit to the primary anoxic unit; after thorough mixing, a denitrification reaction occurs to obtain a primary denitrifying sludge mixture; the primary denitrifying sludge mixture enters the primary aerobic unit, where aerobic decarbonization and thorough nitrification occur under aerobic conditions to obtain a primary nitrifying sludge mixture; a portion of the primary nitrifying sludge mixture is returned to the primary anoxic unit for repeated circulation, and another portion of the primary nitrifying sludge mixture enters a secondary anoxic unit through the flow channel. Under the condition of a carbon source, a further denitrification reaction occurs to obtain a secondary denitrified sludge mixture. The secondary denitrified sludge mixture enters the secondary aerobic unit, where further decarbonization and nitrification reactions occur under aerobic conditions to obtain a secondary aerobic sludge mixture. A portion of the secondary aerobic sludge mixture flows along the end of the secondary aerobic unit into the primary aerobic unit for circulation, while another portion of the secondary aerobic sludge mixture enters a three-phase separator for gas, liquid, and solid separation. The separated clear water flows out, a portion of the separated secondary aerobic sludge is discharged, and another portion of the separated secondary aerobic sludge enters the secondary aerobic unit and circulates with the secondary aerobic sludge mixture into the primary aerobic unit.

[0013] According to the wastewater treatment method of the wastewater treatment system based on the Bardenpho process provided by the present invention, the sludge concentration at the end of the secondary aerobic unit is controlled between 3 g / L and 10 g / L.

[0014] According to the wastewater treatment method of the wastewater treatment system provided by the present invention, the dissolved oxygen content at the end of the primary aerobic unit is ≤1.0 mg / L and / or the oxidation-reduction potential is ≤+100.0 mV.

[0015] According to the wastewater treatment method of the wastewater treatment system provided by the present invention, the reflux ratio of the primary aerobic unit to the primary anoxic unit is greater than or equal to 300%, and the reflux ratio of the secondary aerobic unit to the primary aerobic unit is less than or equal to 200%.

[0016] This invention provides an improved Bardenpho biological system and wastewater treatment method. It uses a three-phase separator instead of a traditional external secondary sedimentation tank, achieving an integrated tank structure that allows for a more compact wastewater treatment plant layout and saves space. The integrated tank structure, with the three-phase separator dividing the secondary reaction tank into anoxic and aerobic units, reduces the need for elevation settings in the process flow, even eliminating the need for significant elevation differences between functional zones. This facilitates the widespread use of more efficient recirculation devices such as airlift units and axial flow pumps, thus reducing recirculation energy consumption.

[0017] Secondly, by employing a highly efficient reflux method, it is easy to achieve a higher reflux ratio in the primary nitrification-denitrification reaction process, meaning it is easy to surpass the 400% primary mixed liquor reflux ratio of the traditional Bardenpho process under lower energy consumption conditions. A high reflux ratio can significantly improve the total nitrogen removal rate of primary nitrification-denitrification, thereby enhancing the overall nitrogen removal effect; furthermore, a high reflux ratio can effectively improve the shock resistance of the primary nitrification-denitrification zone.

[0018] Finally, considering the activated sludge circulation path, the three-phase separator does not require a separate sludge return device to return the sludge separated from the external secondary sedimentation tank to the anoxic zone. The three-phase separator can automatically return the separated secondary aerobic sludge to the end of the secondary aerobic unit, and then return it to the primary aerobic unit along with the secondary aerobic sludge mixture to participate in the biochemical reaction. The advantages of this return method are twofold: firstly, it saves on the construction of sludge return facilities, reducing investment; secondly, there is no need to worry about the impact of high dissolved oxygen return from the secondary aerobic unit on the denitrification of the primary and secondary anoxic units, as even with high dissolved oxygen levels, the sludge can be reused in the primary aerobic unit; furthermore, this sludge return method helps to significantly increase the average sludge concentration of the entire reactor, further saving floor space. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1This is a schematic diagram of a wastewater treatment system based on the Bardenpho process provided in the first embodiment of the present invention.

[0021] Figure 2 This is an AA cross-sectional view of a wastewater treatment system based on the Bardenpho process provided in the first embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of a wastewater treatment system based on the Bardenpho process provided in the second embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram of a wastewater treatment system based on the Bardenpho process provided in the third embodiment of the present invention.

[0024] Figure 5 This is a BB cross-sectional view of a wastewater treatment system based on the Bardenpho process provided in the third embodiment of the present invention.

[0025] Figure 6 This is a flowchart of a wastewater treatment method based on the Bardenpho process, provided in the second aspect of the present invention.

[0026] Figure label:

[0027] 1. Primary anoxic unit; 10. Inlet pipe; 11. First guide plate; 12. First reflux device; 120. First reflux channel; 13. Fourth water passage hole; 2. Primary aerobic unit; 21. Second guide plate; 22. Dissolved oxygen monitoring element; 23. Oxidation-reduction potential monitoring element; 230. Flow channel; 24. First water passage hole; 25. Third reflux device; 250. Third reflux channel; 3. Secondary anoxic unit; 31. Third guide plate; 32. Second water passage hole; 3 3. Third water passage hole; 34. Fourth guide plate; 4. Secondary aerobic unit; 41. Second reflux device; 420. Second reflux channel; 5. Three-phase separator; 50. Mud-water separation chamber; 51. Water collection tank; 52. Combined packing; 53. Third plate; 54. First plate; 55. Second plate; 500. Clear water outlet; 510. Drainage pipe; 511. Sludge discharge pipe; 512. Sludge discharge branch pipe; 450. Mixing channel; 451. Mud-water inlet; 540. Mud-water outlet. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0029] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0031] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0032] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0033] In related technologies, the circulation of activated sludge requires the sludge at the bottom of the sedimentation tank to be transported to the corresponding anoxic tank through a sludge return device, which increases the number of devices and energy consumption, and requires more complex control nodes, thus increasing the complexity of system control.

[0034] To address the issues in the relevant technologies, the following will be discussed in conjunction with... Figures 1-6 The present invention describes a wastewater treatment system based on the Bardenpho process, comprising a primary anoxic unit 1, a primary aerobic unit 2, a secondary anoxic unit 3, a secondary aerobic unit 4, and a three-phase separator 5. The number of these units is determined according to specific design specifications. For example, the primary anoxic unit 1 may contain one or more primary anoxic reaction tanks or reaction vessels, and the primary aerobic unit 2 may also contain one or more primary aerobic reaction tanks or reaction vessels.

[0035] The system comprises four treatment units: Primary Anoxic Unit 1, Primary Aerobic Unit 2, Secondary Anoxic Unit 3, and Secondary Aerobic Unit 4. Each unit has a beginning and an end. Within each unit, wastewater or mixed liquor flows from the beginning to the end. For example, in Primary Anoxic Unit 1, wastewater flows from the beginning to the end. Between adjacent treatment units with a sequential treatment order, wastewater or mixed liquor flows from the end of the previous treatment zone to the beginning of the next. For instance, the mixed liquor in Primary Aerobic Unit 2 enters the beginning of Primary Anoxic Unit 1 from its own end. This process continues in a cyclical manner within the wastewater treatment system, with a defined flow direction.

[0036] like Figure 1 As shown, a wastewater inlet pipe 10 is installed at the beginning of the primary anoxic unit 1, which is used to introduce wastewater into the primary anoxic unit 1. After the wastewater enters the primary anoxic unit 1, the carbon source in the wastewater is fully mixed with the primary nitrifying sludge mixture circulating in the primary anoxic unit 1 to undergo a denitrification reaction, thereby obtaining a primary denitrifying sludge mixture.

[0037] It is understandable that when the primary anoxic unit 1 includes two or more primary aerobic reactors, connecting the two or more primary aerobic reactors in series can improve the overall treatment efficiency. The illustrations and descriptions in this application use a single primary aerobic reactor as an example.

[0038] A first water passage 24 or a first return channel 120 is provided between the beginning of the primary aerobic unit 2 and the end of the primary anoxic unit 1. A first water passage 24 or a first return channel 120 is also provided between the end of the primary aerobic unit 2 and the beginning of the primary anoxic unit 1. Furthermore, a flow channel 230 is provided within the primary aerobic unit 2. Wastewater passes through the primary nitrifying sludge to form a primary denitrifying sludge mixture. This primary denitrifying sludge mixture enters the beginning of the primary aerobic unit 2 through the end of the primary anoxic unit 1, where decarbonization and full nitrification reactions occur under aerobic conditions, yielding a primary nitrifying sludge mixture. A portion of this primary nitrifying sludge mixture is returned to the primary anoxic unit 1 for repeated circulation, while the other portion is output to the next process via the flow channel 230.

[0039] In specific settings, such as Figure 1 and Figure 3 As shown, the first-stage aerobic unit 2 and the first-stage anoxic unit 1 are arranged side by side, and the first-stage aerobic unit 2 and the first-stage anoxic unit 1 are separated by a partition. The first water passage hole 24 or the first return channel 120 on the partition at the beginning of the first-stage anoxic unit 1 enables the return flow between the two treatment units. The first water passage hole 24 or the first return channel 120 on the partition at the end of the first-stage anoxic unit 1, and the first return device 12 promotes the circulation between the two treatment units.

[0040] like Figure 4 As shown, in another embodiment, the first end of the anoxic unit 1 is connected to the first end of the two treatment units through the fourth water passage 13, and a third return channel 250 is provided on the second guide plate 21. The third return device 25 is set in the third return channel 250. The water flows in the first aerobic unit 2 on both sides of the second guide plate 21 through the lifting and pushing action of the third return device 25, thereby realizing circulation through the connection of the two positions.

[0041] The first end of the secondary anoxic unit 3 is connected to the end of the primary aerobic unit 2 through the flow channel 230. Part of the primary nitrifying sludge in the primary aerobic unit 2 is discharged into the secondary anoxic unit 3 through the flow channel 230, where it undergoes further nitrification under the condition of a carbon source, resulting in a secondary denitrifying sludge mixed liquor.

[0042] The first end of the secondary aerobic unit 4 is connected to the end of the secondary anoxic unit 3, and the end of the secondary aerobic unit 4 is connected to the primary aerobic unit 2 through the second return channel 420. Further denitrification occurs in the secondary anoxic unit 3 to obtain a secondary denitrified sludge mixture. This secondary denitrified sludge mixture enters the secondary aerobic unit 4 through the secondary anoxic unit 3, where further decarbonization and nitrification reactions occur under aerobic conditions to obtain a secondary aerobic sludge mixture. A portion of the secondary aerobic sludge mixture enters the primary aerobic unit 2 along the second return channel 420 at the end of the secondary aerobic unit 4 for circulation.

[0043] A three-phase separator 5 is located between the secondary anoxic unit 3 and the secondary aerobic unit 4. The three-phase separator 5 isolates the two units, and its inlet is connected to the secondary aerobic unit 4. The three-phase separator 5 acts as a baffle, dividing the main body of the secondary reaction tank into two independent areas: the aforementioned secondary anoxic unit 3 and the aforementioned secondary aerobic unit 4. The secondary anoxic unit 3 bypasses the three-phase separator 5, allowing its end to connect to the beginning of the secondary aerobic unit 4. A portion of the secondary aerobic sludge mixture remaining in the secondary aerobic unit 4 enters the three-phase separator 5 for gas, liquid, and solid separation. The separated clear water flows out, a portion of the separated secondary aerobic sludge is discharged, and the remaining separated secondary aerobic sludge enters the secondary aerobic unit 4 along with the secondary aerobic sludge mixture, circulating into the primary aerobic unit 2.

[0044] like Figure 1 , Figure 3 and Figure 4 As shown, the arrangement of the three-phase separator 5 enables the secondary anoxic unit 3 and the secondary aerobic unit 4 to form a parallel arrangement structure. This allows the secondary anoxic unit 3 and the secondary aerobic unit 4 to share an isolation sidewall with the primary aerobic unit 2, forming an integrated pool structure. This results in a smaller overall system space, which is beneficial for reducing the elevation settings in the process flow and can reduce reflux energy consumption.

[0045] In a specific configuration, the three-phase separator 5 includes a first plate 54, a second plate 55, and a third plate 53. The first plate 54 is disposed between the secondary aerobic unit 4 and the secondary anoxic unit 3, and one end of the first plate 54 is sealed to the bottom surface of the secondary aerobic unit 4 to isolate the secondary anoxic unit 3 from the secondary aerobic unit 4. The second plate 55 is located inside the secondary aerobic unit 4 and is disposed on one side of the first plate 54. The second plate 55 and a portion of the first plate 54 form a mud-water separation chamber 50. A mud-water inlet 451 is formed at the bottom of the mud-water separation chamber 50, and a mud-water separation chamber 50 is formed at the top. There is a clean water outlet 500, and a water collection tank 51 is provided at the clean water outlet 500. The water collection tank 51 is connected to the drainage pipe 510. The third plate 53 is located on one side of the second plate 55. A part of the third plate 53 and a part of the second plate 55 form a mixing channel 450. The remaining part of the third plate 53, the remaining part of the second plate 55 and the remaining part of the first plate 54 together form a buffer chamber. The buffer chamber is located below the mud-water separation chamber 50. The mixing channel 450 and the mud-water inlet 451 are both connected to the buffer chamber. A mud-water outlet 540 is formed at the bottom of the buffer chamber. The mud-water outlet 540 is connected to the bottom of the secondary aerobic unit 4. The first plate 54 divides the secondary reaction tank into two parallel spaces. The secondary aerobic sludge mixture in the secondary aerobic unit 4 enters the buffer chamber through the mixing channel 450, and then enters the sludge-water separation chamber 50 through the sludge-water inlet 451 for sludge-water separation. The separated clear water is discharged through the drainage pipe 510 connected to the top of the sludge-water separation chamber 50. The separated sludge enters the secondary aerobic unit 4 through the sludge-water outlet 540, and enters the primary aerobic unit 2 along with the secondary aerobic sludge mixture to complete the circulation of activated sludge.

[0046] Understandably, in this embodiment, the three-phase separator 5 eliminates the need for an external secondary sedimentation tank, thus removing the sludge return device used for activated sludge return. This reduces the number of control nodes for the sludge return device, lowers system complexity, and allows some sludge to be quickly separated and fed into the primary aerobic unit 2 along with the secondary aerobic sludge mixture for reuse. Furthermore, the separation achieved by the three-phase separator 5 enables the parallel arrangement of the secondary anoxic unit 3 and the secondary aerobic unit 4, resulting in a more compact overall layout. This reduces the height difference between stages, thereby achieving low energy consumption and high-efficiency return.

[0047] like Figure 2As shown, in practical applications, the bottom of the sludge-water separation chamber 50 formed by the first plate 54 and the second plate 55 is relatively inclined, making the bottom of the sludge-water separation chamber 50 a hopper-shaped structure, which facilitates the flow of sludge after separation. The portion of the first plate 54 extending downwards from the bottom of the sludge-water separation chamber 50 is a sloping structure, forming a buffer chamber. The sludge-water outlet 540 is formed through the gap between the first plate 54 and the third plate 53, thereby enabling the sludge to quickly reach the secondary aerobic unit 4 from the sludge-water separation chamber 50, improving the sludge circulation efficiency.

[0048] like Figure 1 As shown in the figure, the arrows indicate the direction of water flow in water treatment using this invention. The specific operation is as follows.

[0049] Wastewater containing abundant carbon source pollutants is introduced into the primary anoxic unit 1 through the inlet pipe 10. The primary nitrified sludge mixture from the primary aerobic unit 2 is introduced into the primary anoxic unit 1 through the first water passage 24. The carbon source pollutants mix with the primary nitrified sludge mixture returned to the primary anoxic unit 1, resulting in a denitrification reaction. To improve the mixing degree between the carbon source and the primary nitrified sludge mixture, a stirring device is installed in the primary anoxic unit 1 to achieve better mixing. This stirring device includes a submersible mixer and a submersible jet mixer.

[0050] The denitrification mixture is lifted and propelled by the first reflux device 12 into the head end of the primary aerobic unit 2. Under aerobic conditions, the denitrification mixture undergoes aerobic decarbonization and full nitrification to obtain primary nitrified sludge mixture. A portion of the primary nitrified sludge mixture at the end of the primary aerobic unit 2 enters the primary anoxic unit 1 through the first water passage 24 to form a cycle, while the other portion of the primary nitrified sludge enters the secondary denitrification and nitrification reaction zone through the flow channel 230 for secondary reaction.

[0051] The primary nitrified sludge mixture entering the secondary anoxic unit 3 undergoes a secondary denitrification reaction under the presence of a carbon source. The mixture after the secondary denitrification reaction enters the beginning of the secondary aerobic unit 4 through the secondary anoxic unit 3.

[0052] The mixed liquor after the secondary denitrification reaction in the secondary aerobic unit 4 undergoes further decarbonization and nitrification under aerobic conditions to obtain a secondary aerobic sludge mixed liquor. A portion of the secondary aerobic sludge mixed liquor is pumped into the primary aerobic unit 2 by the lifting and propulsion action of the second reflux device 41 for circulation. The remaining portion is fed into the three-phase separator 5 for separation. The separated aerobic sludge is located in the three-phase separator 5 and discharged through the sludge discharge pipe. The remaining aerobic sludge is returned to the secondary aerobic unit 4 and enters the primary aerobic unit 2 along with the secondary aerobic sludge mixed liquor. The separated clean water is output through the drain pipe 510, and the separated gas is discharged through the secondary aerobic unit 4 along the mixing channel 450.

[0053] In this system, the secondary anoxic unit 3 and the secondary aerobic unit 4 jointly complete the secondary reaction. Through the arrangement of the three-phase separator 5 and the third and fourth guide plates 31 and 34 of the secondary anoxic unit 3, the flow path in the secondary reaction zone is roughly U-shaped. This U-shaped arrangement extends the flow path of the secondary reaction, thereby improving the efficiency of both the secondary denitrification and aerobic reactions.

[0054] Understandably, in this embodiment, firstly, the use of a three-phase separator 5 instead of a traditional external secondary sedimentation tank enables an integrated tank structure, making the wastewater treatment plant layout more compact and saving land. Adopting an integrated tank structure and dividing the secondary reaction tank into a secondary anoxic unit 3 and a secondary aerobic unit 4 via the three-phase separator 5 helps reduce elevation settings in the process flow, even eliminating the need for significant elevation differences between functional zones. This facilitates the widespread use of more efficient recirculation devices such as airlift devices and axial flow pumps, thus reducing recirculation energy consumption.

[0055] Secondly, by employing a highly efficient reflux method, it is easy to achieve a higher reflux ratio in the primary nitrification-denitrification reaction process, meaning it is easy to surpass the 400% primary mixed liquor reflux ratio of the traditional Bardenpho process under lower energy consumption conditions. A high reflux ratio can significantly improve the total nitrogen removal rate of primary nitrification-denitrification, thereby enhancing the overall nitrogen removal effect. Furthermore, a high reflux ratio can effectively improve the shock resistance of the primary nitrification-denitrification zone, which is the denitrification reaction within the primary anoxic unit 1.

[0056] Secondly, from the perspective of the activated sludge circulation path, the three-phase separator 5 does not require a separate sludge return device to return the sludge separated from the external secondary sedimentation tank to the anoxic zone. The three-phase separator 5 can automatically return the separated secondary aerobic sludge to the end of the secondary aerobic unit 4, and then return it to the primary aerobic unit 2 along with the secondary aerobic sludge mixture to participate in the biochemical reaction. The advantages of this return method are that, on the one hand, it can save on the construction of sludge return facilities, saving investment; on the other hand, there is no need to worry about the impact of the high dissolved oxygen return from the secondary aerobic unit 4 on the denitrification of the primary anoxic unit 1 and the secondary anoxic unit 3, and even if the dissolved oxygen is high, it can be reused in the primary aerobic unit 2; in addition, this sludge return method is also conducive to greatly increasing the average sludge concentration of the entire reactor, further saving the footprint.

[0057] Finally, this embodiment also has the advantages of the Bardenpho process. For example, by setting up the secondary aerobic unit 4, it can effectively prevent the carbon source that is not fully utilized in the secondary denitrification from entering the effluent and causing carbon source breakthrough.

[0058] According to one embodiment of the present invention, guide vanes are provided in the primary anoxic unit 1, the primary aerobic unit 2, and the secondary anoxic unit 3. The guide vanes are adapted to adjust the flow path of the fluid. By adjusting the flow path within the treatment unit through the guide vanes, nitrification and denitrification reactions can be promoted, thereby improving the wastewater treatment effect.

[0059] According to one embodiment of the present invention, a third guide plate 31 and a fourth guide plate 34 are provided in the secondary anoxic unit 3. The third guide plate 31 divides the secondary anoxic unit 3 into two regions. A second water passage hole 32 is provided on the third guide plate 31. The fourth guide plate 34 is provided at the end of the secondary anoxic unit 3, and a third water passage hole 33 is provided on the fourth guide plate, which communicates with the beginning of the secondary aerobic unit 4 through the third water passage hole 33. The third guide plate 31 can be a single section, such as... Figure 1 As shown, the third guide plate 31 can also be multi-segmented, which can divide the secondary anoxic unit 3 into multiple regions. The third water passage 33 is used to connect the secondary anoxic unit 3 and the secondary aerobic unit 4. The second water passage 32 and the third water passage 33 can achieve flow balance between the treatment units, ensuring that the water flows in a tortuous manner within the system and avoiding local short-circuiting. This helps to improve the overall treatment efficiency of the system.

[0060] In specific settings, such as Figure 1 or Figure 3As shown, the third guide plate 31 is installed within the secondary anoxic unit 3, roughly dividing the secondary anoxic unit 3 into two regions, thereby extending the processing path within the secondary anoxic unit 3 and improving processing efficiency. Furthermore, the arrangement of the third guide plate 31 and the fourth guide plate 34 allows the secondary anoxic unit 3 and the secondary aerobic unit 4 to combine into a roughly U-shaped structure.

[0061] Understandably, the arrangement of the third guide plate 31 and the fourth guide plate 34 forms a roughly U-shaped structure, making the entire system layout more compact, effectively reducing the system's elevation difference, facilitating the use of a more efficient recirculation device, and reducing recirculation energy consumption. Furthermore, the third guide plate 31 extends the treatment path of the secondary anoxic unit 3, thereby improving the treatment effect of the secondary anoxic unit 3.

[0062] In the specific example, both the first reflux device 12 and the second reflux device 41 are air-stripping reflux devices. In this embodiment, the arrangement of the three-phase separator 5 makes the overall system structure compact and the system height difference small, thus allowing for the installation of an air-stripping reflux device at the reflux end. The air-stripping reflux device can increase the reflux ratio, especially in the primary nitrification and denitrification reaction process. This reflux method can break through the 400% reflux ratio limit with lower energy consumption, thereby improving the total nitrogen removal rate of primary nitrification and denitrification, and thus improving the total nitrogen removal rate of the entire system.

[0063] like Figure 1 As shown in one example, the first-stage anoxic unit 1 has a first guide plate 11, and the first-stage aerobic unit 2 has a second guide plate 21. Both guide plates are connected to two divided baffles, and both guide plates are straight baffles. The two guide plates allow the wastewater in each treatment unit to bypass the baffles when flowing from the beginning to the end, thereby increasing the flow path. In this example, the bottom of the end of the first-stage anoxic unit 1 is connected to a first return channel 120, and a first return device 12 is set in the first return channel 120. Under the action of the first return device 12, one position of the two treatment units can be connected. The beginning position of the first-stage anoxic unit 1 is connected to a first water passage 24, and the other position of the two treatment units can be connected through the first water passage 24, thereby achieving circulation through the connection of the two positions.

[0064] like Figure 3As shown in another example, the first guide plate 11 connected within the first-stage anoxic unit 1 is composed of multiple plates, while the second guide plate 21 within the first-stage aerobic unit 2 is a straight plate structure connected within the first-stage aerobic unit 2. The combined plates are positioned in the middle of the first-stage anoxic unit 1, requiring the flowing water to flow around the combined plates, thus increasing the flow path. In this example, a first return channel 120 is connected to the top of the first end of the first-stage anoxic unit 1, and a first return device 12 is disposed within the first return channel 120. The first return channel 120 enables communication between the two treatment units. A first water passage 24 is connected to the end of the first-stage anoxic unit 1, enabling communication between the two treatment units at another location, thereby achieving circulation through the connection between the two locations.

[0065] like Figure 4 As shown, in one example, the first guide plate 11 connected within the primary anoxic unit 1 is composed of multiple plates. The primary aerobic unit 2 is connected near its center to a straight-plate-shaped second guide plate 21, which divides the primary aerobic unit 2. In this example, the first end of the primary anoxic unit 1 is connected to the first end of the two treatment units via a first water passage 24, and the last end of the primary anoxic unit 1 is connected to the first end of the two treatment units via a fourth water passage 13. A third return channel 250 is provided on the second guide plate 21, and a third return device 25 is installed within the third return channel 250. The lifting and pushing action of the third return device 25 enables water to flow within the primary aerobic units 2 on both sides of the guide plate, thus achieving circulation through the connection between the two locations.

[0066] Of course, in other embodiments, there can be multiple guide vanes. Multiple guide vanes can guide the water to flow a longer path, thereby improving the water treatment effect.

[0067] According to one embodiment provided by the present invention, such as Figure 2 As shown, the bottom of the sludge-water separation chamber 50 is connected to a sludge discharge pipe 511; the middle of the sludge-water separation chamber 50 has a combined packing material 52, and the combined packing material 52 is equipped with a cleaning component (not shown in the figure). The combined packing material 52 can be used for sludge-water separation of aerobic sludge mixture in the sludge-water separation chamber 50. The setting of the combined packing material 52 can improve the separation efficiency, and the cleaning device can clean the combined packing material 52 to prevent the pores from being blocked during long-term separation. Among them, multiple sludge discharge branch pipes 512 are connected to the sludge discharge pipe 511, and the sludge discharge branch pipes 512 extend into the sludge-water separation chamber 50 to discharge aerobic sludge.

[0068] In other embodiments, such as Figure 5As shown, the location of the sludge discharge pipe 511 is different. Specifically, the inlet end of the sludge discharge pipe 511 is located in the middle of the sludge-water separation chamber 50, and the sludge discharge pipe is set along the extension direction of the three-phase separator 5 so that it can discharge the separated sludge.

[0069] In specific configurations, the combined packing 52 can be a porous tube or inclined plate, etc. The cleaning components can be clean water spray heads and / or perforated pipe aeration. The clean water spray heads are connected to a high-pressure water pump, which drives clean water to spray through the spray heads and pores to clear blockages. Alternatively, the perforated pipes can be connected to a blower, and the flow generated by aeration cleans the packing. It is understood that the cleaning components can be located above or below the combined packing 52, with different placement positions depending on the cleaning method. For example, a perforated pipe located at the bottom of the combined packing 52, connected to a blower, can achieve cleaning of the combined packing 52.

[0070] According to one embodiment of the present invention, the end of the primary aerobic unit 2 has a dissolved oxygen monitoring element 22 (DO) and / or an oxidation-reduction potential monitoring element 23 (ORP).

[0071] Understandably, the dissolved oxygen monitoring element 22 and the oxidation-reduction potential monitoring element 23 can provide real-time feedback on the solution oxygen content of the primary nitrification sludge mixed liquor, enabling effective regulation and control through monitoring. Specifically, an aeration device is installed at the bottom of the primary aerobic unit 2, and the oxygen content of the primary nitrification sludge mixed liquor within the primary aerobic unit 2 can be adjusted by controlling the airflow through the aeration device.

[0072] By controlling the low dissolved oxygen concentration at the end of the primary aerobic unit 2, the adverse effects of dissolved oxygen carried by the high return flow of primary nitrification and denitrification on the denitrification of primary anoxic unit 1 can be effectively mitigated. At the same time, the dissolved oxygen carried by the primary nitrification sludge mixed liquor entering the secondary anoxic unit 3 can be effectively reduced, thereby reducing the carbon source consumption of denitrification in the secondary anoxic unit 3, improving the denitrification efficiency of the secondary anoxic unit 3, and also helping to reduce the amount of sludge generated.

[0073] like Figure 6 As shown, another aspect of the present invention provides a wastewater treatment method using a wastewater treatment system based on the Bardenpho process provided by any of the above claims, comprising:

[0074] S200. Wastewater is introduced into the primary anoxic unit. The carbon source in the wastewater is mixed with the primary nitrifying sludge that is returned to the primary anoxic unit from the end of the primary aerobic unit. After thorough mixing, a denitrification reaction occurs to obtain a primary denitrifying sludge mixture.

[0075] S210. The primary denitrifying sludge mixture enters the primary aerobic unit and undergoes aerobic decarbonization and full nitrification under aerobic conditions to obtain the primary nitrifying sludge mixture.

[0076] S220. A portion of the primary nitrifying sludge mixture is returned to the primary anoxic unit for repeated circulation, while another portion of the primary nitrifying sludge mixture enters the secondary anoxic unit through the flow channel. Under the condition of having a carbon source, a further denitrification reaction occurs to obtain a secondary denitrifying sludge mixture.

[0077] S230. The secondary denitrification sludge mixture enters the secondary aerobic unit and undergoes further decarbonization and nitrification reactions under aerobic conditions to obtain a secondary aerobic sludge mixture.

[0078] S240. A portion of the secondary aerobic sludge mixture enters the primary aerobic unit along the end of the secondary aerobic unit for circulation, while another portion of the secondary aerobic sludge mixture enters a three-phase separator for gas, liquid, and solid separation. The separated clear water flows out, a portion of the separated secondary aerobic sludge is discharged, and another portion of the separated secondary aerobic sludge enters the secondary aerobic unit and circulates with the secondary aerobic sludge mixture into the primary aerobic unit.

[0079] According to one embodiment of the present invention, the sludge concentration at the end of the secondary aerobic unit is controlled between 3 g / L and 10 g / L. By controlling the sludge concentration, efficient sludge utilization can be achieved, and sludge accumulation can be avoided.

[0080] In a specific example, the dissolved oxygen (DO) at the end of the primary aerobic unit is ≤1.0 mg / L and / or the oxidation-reduction potential (ORP) is ≤+100.0 mV. This embodiment, by setting up dissolved oxygen and / or ORP monitoring elements, can provide real-time feedback on the dissolved oxygen content of the primary nitrification sludge mixed liquor. Monitoring allows for effective regulation and control. Under high sludge concentration conditions, the aeration airflow is controlled by maintaining a low dissolved oxygen concentration. The control method is stable, and the low dissolved oxygen control strategy improves the oxygenation efficiency of the aeration device, saving operating energy.

[0081] In a specific example, the recirculation ratio from the primary aerobic unit to the primary hypoxic unit is greater than or equal to 300%, and the recirculation ratio from the secondary aerobic unit to the primary aerobic unit is less than or equal to 200%.

[0082] It is understandable that by controlling a larger reflux ratio from the primary aerobic unit to the primary anoxic unit, the total nitrogen removal rate of the primary nitrification-denitrification reaction can be improved, thereby further achieving the total nitrogen removal rate of the entire process. By controlling the reflux ratio from the secondary aerobic unit to the primary aerobic unit, the primary nitrification-denitrification reaction can be controlled, which is beneficial to improving the water treatment effect.

[0083] In summary, the wastewater treatment system and method based on the Bardenpho process provided in the embodiments of the present invention have the following advantages:

[0084] 1. The integrated structure is simple and not only saves space but also reduces the elevation loss of the reactor, which is conducive to energy-saving design. For example, it can greatly reduce the lifting height of the two-stage nitrification sludge mixed liquor recirculation, saving long-term operating energy consumption.

[0085] 2. The use of a three-phase separator simplifies the operation and management of traditional secondary sedimentation tanks. On the one hand, it eliminates the need for a sludge scraper required for secondary sedimentation, reducing the number of operation and management units. On the other hand, it eliminates the need for a separate sludge return facility, saving investment and operating energy consumption.

[0086] 3. The use of a three-phase separator can further increase the volume of the existing tank for use as a biochemical reaction zone, increase the biochemical reaction time, and help increase the amount of water treated and save floor space.

[0087] 4. The primary nitrification sludge mixed liquor recirculation adopts air-lift recirculation instead of traditional mechanical water pump recirculation, which can achieve a large recirculation ratio condition for primary nitrification and denitrification reactions with low energy consumption. Combined with the use of a three-phase separator, it can greatly increase the average sludge concentration in the reactor, improve the treatment efficiency per unit tank volume, thereby further saving land and reducing construction costs.

[0088] 5. In the primary nitrification-denitrification reaction zone, under the premise of a large reflux ratio and high sludge concentration, adopting a low dissolved oxygen and / or redox potential control strategy is beneficial to improving the utilization rate of dissolved oxygen, thereby reducing the operating energy consumption of the reactor, and at the same time greatly improving the shock resistance of the primary reaction zone.

[0089] 6. In the primary nitrification-denitrification reaction zone, the environment created by the large reflux ratio, high sludge concentration, and low dissolved oxygen can further improve the removal rate of Kjeldahl nitrogen and total nitrogen in the primary nitrification-denitrification reaction zone.

[0090] 7. The use of low dissolved oxygen and / or redox potential control strategies in the primary nitrification and denitrification reaction zone is beneficial to increasing the nitrogen removal ratio of simultaneous nitrification and denitrification and short-cut nitrification and denitrification in the primary aerobic unit, which is beneficial to saving energy consumption and carbon source consumption, and also beneficial to reducing sludge production in the primary reaction zone.

[0091] 8. The low dissolved oxygen and / or redox potential control strategy adopted in the primary nitrification-denitrification reaction zone provides better reaction conditions for denitrification in the secondary anoxic unit, which helps to save carbon source consumption in secondary denitrification, save operating costs, and reduce sludge production in the secondary reaction zone.

[0092] 9. The three-phase separator returns the secondary aerobic sludge to the secondary aerobic unit along the process flow, and then returns it to the primary aerobic unit along with the secondary aerobic sludge mixture for recycling reaction. There is no need to worry about the impact of the high dissolved oxygen return from the secondary aerobic unit on the denitrification of the primary and secondary anoxic units. Even if the dissolved oxygen is high, it can be reused when returned to the primary aerobic unit, which is convenient for control and saves operating energy consumption.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wastewater treatment method based on the Bardenpho process wastewater treatment system, characterized in that, The wastewater treatment system includes: A primary anoxic unit, the first end of which is connected to the inlet water pipe; A primary aerobic unit is provided with a first water passage or a first reflux device between the first end of the primary aerobic unit and the end of the primary anoxic unit, and a first water passage or a first reflux device between the end of the primary aerobic unit and the first end of the primary anoxic unit. The primary aerobic unit is also provided with a flow channel. A secondary hypoxic unit, the first end of which is connected to the end of the primary aerobic unit through the flow channel; A secondary aerobic unit, the first end of which is connected to the end of the secondary hypoxic unit, and the end of which is connected to the primary aerobic unit through a second reflux channel, wherein a second reflux device is provided in the second reflux channel; A three-phase separator is disposed between the secondary anoxic unit and the secondary aerobic unit. The three-phase separator is used to isolate the secondary anoxic unit and the secondary aerobic unit, and the inlet end of the three-phase separator is connected to the secondary aerobic unit. The three-phase separator includes: A first plate is disposed between the secondary aerobic unit and the secondary anoxic unit, and one end of the first plate is sealed to the bottom surface of the secondary aerobic unit so as to isolate the secondary anoxic unit from the secondary aerobic unit through the first plate. The second plate is located in the secondary aerobic unit and is disposed on one side of the first plate. The second plate and a part of the first plate form a mud-water separation chamber. A mud-water inlet is formed at the bottom of the mud-water separation chamber, and a clear water outlet is formed at the top of the mud-water separation chamber. A water collection tank is provided at the clear water outlet, and the water collection tank is connected to a drainage pipe. A third plate is disposed on one side of the second plate. A portion of the third plate and a portion of the second plate form a mixing channel. The remaining portions of the third plate, the second plate, and the first plate together form a buffer cavity. The buffer cavity is located below the mud-water separation cavity. The mixing channel and the mud-water inlet are both connected to the buffer cavity. A mud-water outlet is formed at the bottom of the buffer cavity, and the mud-water outlet is connected to the secondary aerobic unit. The wastewater treatment method includes the following steps: Wastewater is fed into the primary anoxic unit. The carbon source in the wastewater is mixed with the primary nitrifying sludge that is returned to the primary anoxic unit from the end of the primary aerobic unit. After thorough mixing, a denitrification reaction occurs to obtain a primary denitrifying sludge mixture. The primary denitrification sludge mixture enters the primary aerobic unit, where aerobic decarbonization and full nitrification reactions occur under aerobic conditions to obtain a primary nitrification sludge mixture. A portion of the primary nitrification sludge mixture is returned to the primary anoxic unit for repeated circulation, while another portion enters the secondary anoxic unit through the flow channel. Under the condition of a carbon source, further denitrification occurs to obtain a secondary denitrification sludge mixture. The secondary denitrification sludge mixture enters the secondary aerobic unit, where it undergoes further decarbonization and nitrification under aerobic conditions to obtain a secondary aerobic sludge mixture. A portion of the secondary aerobic sludge mixture flows into the primary aerobic unit along the end of the secondary aerobic unit for circulation, while another portion enters a three-phase separator for gas, liquid, and solid separation. The separated clear water flows out, and a portion of the separated secondary aerobic sludge is discharged. The remaining portion of the separated secondary aerobic sludge enters the secondary aerobic unit and circulates with the secondary aerobic sludge mixture into the primary aerobic unit. The dissolved oxygen content at the end of the primary aerobic unit is ≤1.0 mg / L and / or the oxidation-reduction potential is ≤+100.0 mV, and the sludge concentration at the end of the secondary aerobic unit is controlled between 3 g / L and 10 g / L.

2. The wastewater treatment method based on the Bardenpho process wastewater treatment system according to claim 1, characterized in that, The first-stage anoxic unit is equipped with a first guide plate, the first-stage aerobic unit is equipped with a second guide plate, and the second-stage anoxic unit is equipped with a third and a fourth guide plate. The first, second, third, and fourth guide plates are all used to adjust the flow path within their respective treatment units.

3. The wastewater treatment method based on the Bardenpho process wastewater treatment system according to claim 1, characterized in that, Both the first reflux device and the second reflux device are air-lift reflux devices.

4. The wastewater treatment method based on the Bardenpho process wastewater treatment system according to claim 1, characterized in that, Both the primary anoxic unit and the secondary anoxic unit are equipped with stirring devices.

5. The wastewater treatment method based on the Bardenpho process wastewater treatment system according to claim 1, characterized in that, The bottom of the mud-water separation chamber is connected to a mud discharge pipe, and the bottom of the mud-water separation chamber is constructed in the shape of a hopper; the middle part of the mud-water separation chamber has a combined packing material, and the combined packing material is equipped with a cleaning component.

6. The wastewater treatment method based on the Bardenpho process wastewater treatment system according to claim 1, characterized in that, The terminal of the primary aerobic unit has a dissolved oxygen monitoring element and / or a redox potential monitoring element.

7. The wastewater treatment method based on the Bardenpho process wastewater treatment system according to claim 1, characterized in that, The reflux ratio from the primary aerobic unit to the primary hypoxic unit is greater than or equal to 300%, and the reflux ratio from the secondary aerobic unit to the primary aerobic unit is less than or equal to 200%.

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