In-situ expansion method and device for sewage treatment system for improving solid flux separation of secondary sedimentation tank and sewage treatment system

Abstract

The application discloses a sewage treatment system in-situ expansion method and device for improving the solid flux separation of a secondary sedimentation tank and a sewage treatment system. The method comprises the following steps: inputting activated sludge in the secondary sedimentation tank into a first separation cavity of a first-stage separation unit, so that the activated sludge is separated through spiral motion in the first separation cavity; according to the operation parameters of the secondary sedimentation tank and the performance of the activated sludge in an aeration tank in a biochemical treatment unit, inputting the activated sludge discharged from one of a first overflow port and a first underflow port of the first-stage separation unit into a second separation cavity of a second-stage separation unit, so that the activated sludge is separated through spiral motion in the second separation cavity, and inputting the activated sludge discharged from one of a second overflow port and a second underflow port of the second-stage separation unit back to the biochemical treatment unit. The method can regulate the solid load and sludge settling performance of the secondary sedimentation tank, increase the solid flux separation of the secondary sedimentation tank, and realize in-situ efficiency improvement and expansion of the sewage treatment system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a sewage treatment system in-situ expansion method for improving the solid flux separation of a secondary sedimentation tank, a sewage treatment system in-situ expansion device for improving the solid flux separation of a secondary sedimentation tank and a sewage treatment system. BACKGROUND

[0002] The activated sludge process is the most widely used biological treatment technology in China's sewage treatment, mainly composed of an aeration tank, a secondary sedimentation tank, a sludge return system and the like. In order to obtain high-quality and clear effluent, the activated sludge not only needs to have the functions of adsorbing, oxidizing and decomposing organic matter, but also needs to have excellent coagulation and sedimentation performance. However, as the discharge standard becomes increasingly stringent, sewage plants usually need to maintain a high sludge concentration to ensure that the effluent quality meets the standard, resulting in the problems of high solid load and poor solid-liquid separation in the secondary sedimentation tank of most sewage plants. SUMMARY

[0003] In view of the problems of high solid load and poor solid-liquid separation efficiency of the secondary sedimentation tank of the existing sewage treatment system, the embodiments of the present application provide a sewage treatment system in-situ expansion method and device for improving the solid flux separation of a secondary sedimentation tank, which can simultaneously regulate and control the solid load and sludge settling performance of the secondary sedimentation tank, increase the solid flux separation of the secondary sedimentation tank, strengthen the solid-liquid separation efficiency of the secondary sedimentation tank, realize the in-situ expansion of the sewage treatment system, effectively improve the efficiency and resilience of the sewage treatment system, reduce the sewage treatment cost, and help the sewage treatment system to improve quality and efficiency.

[0004] The embodiments of the present application provide a sewage treatment system in-situ expansion method for improving the solid flux separation of a secondary sedimentation tank, comprising:

[0005] The activated sludge in the secondary sedimentation tank of the sewage treatment system is input from a first feed port of a first separation unit to a first separation cavity of the first separation unit, so that the activated sludge is separated by spiral motion in the first separation cavity;

[0006] According to the operating parameters of the secondary sedimentation tank and the performance of the activated sludge in the aeration tank in the biochemical treatment unit of the sewage treatment system, the activated sludge discharged from one of a first overflow port and a first underflow port of the first separation unit is input from a second feed port of a second separation unit to a second separation cavity of the second separation unit, so that the activated sludge is separated by spiral motion in the second separation cavity, and the activated sludge discharged from one of a second overflow port and a second underflow port of the second separation unit is returned to the biochemical treatment unit.

[0007] The wastewater treatment system in-situ expansion method for improving the solid flux separation of the secondary sedimentation tank is based on the form and density difference among the microbial aggregates, sludge and biomass attached sludge in the activated sludge, and a two-stage separation unit including the first-stage separation unit and the second-stage separation unit is used to perform gradient classification and separation on different solid phase components in the activated sludge, so as to realize adjustment of the performance of the activated sludge, and further realize precise regulation and control of the settling property of the activated sludge in the aeration tank in the biochemical treatment unit and the solid load of the secondary sedimentation tank.

[0008] The application further provides a wastewater treatment system in-situ expansion device for improving the solid flux separation of a secondary sedimentation tank, which adopts the wastewater treatment system in-situ expansion method for improving the solid flux separation of the secondary sedimentation tank described in the above embodiments, and the device comprises:

[0009] The first-stage separation unit has a first separation cavity, and a first feed inlet, a first underflow outlet and a first overflow outlet which are in communication with the first separation cavity, the first feed inlet is arranged to be in communication with the secondary sedimentation tank of the wastewater treatment system, and the first-stage separation unit is arranged to separate the activated sludge input into the first separation cavity from the first feed inlet through spiral motion; and

[0010] The second-stage separation unit has a second separation cavity, and a second feed inlet, a second underflow outlet and a second overflow outlet which are in communication with the second separation cavity, and one of the first overflow outlet and the first underflow outlet is in communication with the second feed inlet, the second-stage separation unit is arranged to separate the activated sludge input into the second separation cavity from the second feed inlet through spiral motion, and one of the second overflow outlet and the second underflow outlet is arranged to be in communication with the biochemical treatment unit of the wastewater treatment system.

[0011] The application further provides a wastewater treatment system comprising a biochemical treatment unit, a secondary sedimentation tank and the wastewater treatment system in-situ expansion device for improving the solid flux separation of the secondary sedimentation tank, the first feed inlet of the wastewater treatment system in-situ expansion device is in communication with the secondary sedimentation tank, and one of the second underflow outlet and the second overflow outlet of the wastewater treatment system in-situ expansion device is in communication with the biochemical treatment unit.

[0012] Compared with the prior art, the embodiments of the application have the following technical effects:

[0013] 1. The technical scheme of the embodiments of the application is based on the form and density difference among the microbial aggregates, sludge and biomass attached sludge in the activated sludge, and the wastewater treatment system in-situ expansion device used can perform gradient classification and separation on different solid phase components in the activated sludge, so as to realize precise regulation and control of the settling property of the activated sludge in the aeration tank and the solid load of the secondary sedimentation tank;

[0014] 2. The technical solution of this application embodiment can effectively improve the settling performance of activated sludge, increase the solids separation flux of the secondary sedimentation tank, increase the ability of the sewage treatment system to resist hydraulic fluctuations, and realize the in-situ expansion of the sewage treatment system;

[0015] 3. The in-situ expansion device for sewage treatment system in this application embodiment has good versatility and can be applied to the secondary sedimentation tank of existing urban sewage treatment systems, and can improve the operating efficiency of the secondary sedimentation tank.

[0016] 4. The in-situ expansion device for the sewage treatment system in this application has advantages such as simple structure, small footprint, high screening efficiency, and low operation and maintenance costs. Moreover, it does not require the addition of chemicals and is a low-consumption and high-efficiency technology for enhancing the operation efficiency of secondary sedimentation tanks.

[0017] Other features and advantages of this application will be set forth in the following description. Attached Figure Description

[0018] The accompanying drawings are used to provide an understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0019] Figure 1 This is a schematic flowchart of an in-situ expansion method for a wastewater treatment system to increase the solids separation flux in a secondary sedimentation tank, according to an embodiment of this application.

[0020] Figure 2 This is a schematic diagram of the structure of an in-situ expansion device for a wastewater treatment system that increases the throughput of solids separation in a secondary sedimentation tank, according to an embodiment of this application.

[0021] Figure 3 This is a schematic diagram illustrating the working principle of an in-situ expansion device for a wastewater treatment system that increases the throughput of solids separation in a secondary sedimentation tank, according to an embodiment of this application.

[0022] Figure 4 This is a schematic diagram of the structure of an in-situ expansion device for a wastewater treatment system that increases the throughput of solids separation in a secondary sedimentation tank, according to another embodiment of this application.

[0023] Figure 5 This is a schematic diagram illustrating the working principle of an in-situ expansion device for a wastewater treatment system that increases the throughput of solids separation in a secondary sedimentation tank, according to another embodiment of this application.

[0024] Figure 6 This is a schematic diagram of the structure of a wastewater treatment system according to an embodiment of this application;

[0025] Figure 7 This is a schematic diagram of the structure of a wastewater treatment system according to another embodiment of this application.

[0026] Figure label:

[0027] 100 - first separation unit, 200 - second separation unit, 300 - in-situ capacity expansion device of wastewater treatment system

[0028] 1 - outer cylinder, 11 - first end wall, 12 - first separation cavity, 13 - second separation cavity, 14 - first feed port, 15 - first underflow port, 16 - first overflow port, 17 - second feed port, 18 - second underflow port, 19 - second overflow port, 110 - discharge port, 111 - second end wall

[0029] 2 - first inner cone, 21 - first conical section, 211 - second communication cavity, 22 - first cylindrical section

[0030] 3 - second inner cone, 31 - second conical section, 32 - second cylindrical section

[0031] 4 - spiral body, 41 - cylindrical part, 411 - first communication cavity, 42 - spiral blade, 43 - spiral flow channel

[0032] 5 - biochemical treatment unit, 51 - anaerobic zone, 52 - first anoxic zone, 53 - first aerobic zone, 54 - second anoxic zone, 55 - second aerobic zone

[0033] 6 - secondary sedimentation tank, 71 - first internal reflux pipeline, 72 - second internal reflux pipeline, 73 - external reflux pipeline, 8 - primary sedimentation tank DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the present application clearer, the embodiments of the present application will be described in detail below. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other as long as there is no conflict.

[0035] The present application will be further described in detail below in combination with specific examples, but the examples should not be understood as limiting the present application.

[0036] As shown in the following table, the present application provides a method for improving the solid flux separation of a secondary sedimentation tank, which comprises the following steps: Figure 1

[0037] Step S102: inputting the activated sludge in the secondary sedimentation tank of the wastewater treatment system from the first feed port of the first separation unit into the first separation cavity of the first separation unit, so that the activated sludge is separated by the spiral motion in the first separation cavity;

[0038] ​Step S104: Based on the operating parameters of the secondary sedimentation tank and the performance of the activated sludge in the aeration tank of the biochemical treatment unit of the sewage treatment system, the activated sludge discharged from one of the first overflow port and the first underflow port of the first separation unit is fed into the second separation chamber of the second separation unit through the second feed port of the second separation unit, so that the activated sludge is separated by spiral motion in the second separation chamber, and the activated sludge discharged from one of the second overflow port and the second underflow port of the second separation unit is returned to the biochemical treatment unit.

[0039] The in-situ expansion method for wastewater treatment systems that increases the solids separation flux in the secondary sedimentation tank according to embodiments of this application can be achieved through… Figures 2-5 The in-situ expansion device 300 shown in the diagram achieves the goal of increasing the solids separation flux in the secondary sedimentation tank of the wastewater treatment system. Figure 6 and Figure 7 The wastewater treatment system shown is being expanded in situ. In the process of expanding the wastewater treatment system in situ, firstly, the activated sludge in the secondary sedimentation tank 6 can be fed into the first-stage separation unit 100. The activated sludge undergoes spiral motion within the first separation chamber 12 of the first-stage separation unit 100 to separate it, allowing some of the activated sludge to be discharged from the first overflow port 16 and some from the first underflow port 15 of the first-stage separation unit 100. Then, based on the operating parameters of the secondary sedimentation tank 6 in the wastewater treatment system and the performance of the activated sludge in the aeration tank of the biochemical treatment unit 5, the activated sludge from the first separation unit 100 can be further expanded. The activated sludge discharged from the overflow port 16 or the first underflow port 15 is fed into the second-stage separation unit 200. The activated sludge can undergo spiral motion in the second separation chamber 13 of the second-stage separation unit 200 for separation, so that the activated sludge discharged from the second overflow port 19 and the second underflow port 18 of the second-stage separation unit 200 has different performance parameters. According to the operating parameters of the secondary sedimentation tank 6 and the performance of the activated sludge in the aeration tank of the biological treatment unit 5, the activated sludge discharged from the second overflow port 19 or the second underflow port 18 of the second-stage separation unit 200 can be returned to the biological treatment unit 5.

[0040] The in-situ expansion method for wastewater treatment systems that improves the solids throughput of secondary sedimentation tanks provided in this application embodiment is based on the morphological and density differences between microbial aggregates, silt, and biomass-attached silt in activated sludge. It employs a two-stage separation unit (first-stage separation unit 100 and second-stage separation unit 200) to perform gradient-level separation of different solid components in activated sludge, thereby adjusting the performance of activated sludge and achieving precise control over the settling of activated sludge in the aeration tank of the biochemical treatment unit 5 and the solids load of the secondary sedimentation tank 6.

[0041] The in-situ expansion method for wastewater treatment systems that improves the solids separation flux in the secondary sedimentation tank provided in this application embodiment can effectively improve the settling performance of activated sludge, increase the solids separation flux in the secondary sedimentation tank, enhance the wastewater treatment system's ability to resist hydraulic fluctuations, and realize in-situ expansion of the wastewater treatment system.

[0042] In some exemplary embodiments, the operating parameters of the secondary sedimentation tank include the solids load of the secondary sedimentation tank, and the performance of the activated sludge in the aeration tank includes the settling performance of the activated sludge in the aeration tank.

[0043] Based on this, step S104, "according to the operating parameters of the secondary sedimentation tank and the performance of the activated sludge in the aeration tank of the biochemical treatment unit of the wastewater treatment system, the activated sludge discharged from one of the first overflow port and the first underflow port of the first separation unit is input into the second separation chamber of the second separation unit from the second feed port of the second separation unit, so that the activated sludge is separated by spiral motion in the second separation chamber, and the activated sludge discharged from one of the second overflow port and the second underflow port of the second separation unit is returned to the biochemical treatment unit," includes:

[0044] When the settling performance of the activated sludge in the aeration tank of biochemical treatment unit 5 is lower than the set settling performance, and the solid load of the secondary settling tank 6 is not higher than the set solid load, such as Figure 3 As shown, the activated sludge discharged from the first underflow port 15 of the first-stage separation unit 100 is fed into the second separation chamber 13 of the second-stage separation unit 200 through the second inlet port 17 for separation, and the activated sludge discharged from the second underflow port 18 of the second-stage separation unit 200 is returned to the biochemical treatment unit 5.

[0045] When the solid load in the secondary sedimentation tank 6 is higher than the set solid load, and the settling performance of the activated sludge in the aeration tank of the biological treatment unit 5 is not lower than the set set settling performance, such as Figure 5 As shown, the activated sludge discharged from the first overflow port 16 of the first-stage separation unit 100 is fed into the second separation chamber 13 of the second-stage separation unit 200 through the second feed port 17 for separation, and the activated sludge discharged from the second overflow port 19 of the second-stage separation unit 200 is returned to the biochemical treatment unit 5.

[0046] When the settling performance of the activated sludge in the aeration tank of biochemical treatment unit 5 is lower than the set settling performance, and the solid load in the secondary settling tank 6 is higher than the set solid load, such as Figure 5As shown, the activated sludge discharged from the first overflow port 16 of the first separation unit 100 is input into the second separation cavity 13 of the second separation unit 200 from the second feed port 17 of the second separation unit 200, and the activated sludge discharged from the second underflow port 18 of the second separation unit 200 is returned to the biochemical treatment unit 5.

[0047] When the settling property of the activated sludge in the aeration tank of the biochemical treatment unit 5 is poor (lower than the set settling property), but the solid load of the secondary sedimentation tank 6 is not higher than the set solid load, the underflow sludge discharged from the first underflow port 15 of the first separation unit 100 is used as the feed sludge of the second separation unit 200, the underflow sludge discharged from the second underflow port 18 of the second separation unit 200 is returned to the biochemical treatment unit 5, fine sand (condensation nucleus) is provided for the biochemical treatment unit 5 to improve the settling property of the activated sludge and improve the solid-liquid separation capacity of the secondary sedimentation tank 6. The overflow sludge discharged from the first overflow port 16 of the first separation unit 100 and the second overflow port 19 of the second separation unit 200 can be discharged to the sludge thickening tank.

[0048] When the solid load of the secondary sedimentation tank 6 is high (higher than the set solid load), but the settling property of the activated sludge in the aeration tank of the biochemical treatment unit 5 is not lower than the set settling property, the overflow sludge discharged from the first overflow port 16 of the first separation unit 100 is used as the feed sludge of the second separation unit 200, the overflow sludge discharged from the second overflow port 19 of the second separation unit 200 is returned to the biochemical treatment unit 5 to increase the ratio of mixed liquor volatile suspended solid (MLVSS) to mixed liquid suspended solids (MLSS), increase the microbial share of the activated sludge, reduce the sludge concentration of the biochemical treatment unit 5, and thus reduce the solid load of the secondary sedimentation tank 6. The underflow sludge discharged from the first underflow port 15 of the first separation unit 100 and the second underflow port 18 of the second separation unit 200 is discharged to the sludge thickening tank.

[0049] When the settling property of the activated sludge in the aeration tank of the biochemical treatment unit 5 is poor, and the solid load of the secondary sedimentation tank 6 is high, the overflow sludge discharged from the first overflow port 16 of the first separation unit 100 is used as the feed sludge of the second separation unit 200, the underflow sludge discharged from the second underflow port 18 of the second separation unit 200 is returned to the biochemical treatment unit 5 to improve the MLVSS / MLSS ratio, reduce the solid load, and improve the settling property of the activated sludge. The underflow sludge discharged from the first underflow port 15 of the first separation unit 100 and the second overflow port 19 of the second separation unit 200 is discharged to the sludge thickening tank.

[0050] The method of the embodiment of the present application adopts two-stage separation units to perform gradient classification and separation on different solid components of sludge based on the form and density difference between microbial aggregates, silt, and biomass-attached silt in the activated sludge, so as to realize precise regulation and control of the settling property of the activated sludge in the aeration tank in the biochemical treatment unit 5 and the solid load of the secondary settling tank 6. The method of the embodiment of the present application can effectively improve the settling property of the activated sludge, increase the separation solid flux of the secondary settling tank 6, increase the ability of the sewage treatment system to resist hydraulic fluctuation impact, and realize in-situ expansion of the sewage treatment system.

[0051] In some exemplary embodiments, the method for in-situ expansion of the sewage treatment system for improving the separation solid flux of the secondary settling tank further comprises:

[0052] The sludge discharged from the other of the first overflow port and the first underflow port of the first-stage separation unit is transported to the sludge thickening tank, and the sludge discharged from the other of the second overflow port and the second underflow port of the second-stage separation unit is transported to the sludge thickening tank.

[0053] The sludge discharged from the other of the first underflow port 15 and the first overflow port 16 of the first-stage separation unit 100 is transported to the sludge thickening tank of the sewage treatment system, and the sludge discharged from the other of the second underflow port 18 and the second overflow port 19 of the second-stage separation unit 200 is transported to the sludge thickening tank of the sewage treatment system, so as to reduce the volume of the sludge, and further reduce the subsequent treatment cost of the sludge and the impact on the environment.

[0054] In some exemplary embodiments, the pressure of the activated sludge input into the first feed port 14 of the first-stage separation unit 100 is 0.2 MPa to 0.5 MPa, such as 0.3 MPa.

[0055] The pressure of the activated sludge input into the first-stage separation unit 100 is 0.2 MPa to 0.5 MPa, and the two-stage separation unit can realize efficient and effective treatment of the activated sludge, so as to improve the performance of the activated sludge after being treated by the two-stage separation unit.

[0056] In some exemplary embodiments, the concentration of the activated sludge input into the first feed port 14 of the first-stage separation unit 100 ranges from 2.0 g / L to 50.0 g / L.

[0057] Of course, the pressure and concentration range of the activated sludge input into the first-stage separation unit 100 are not limited to the above ranges, and can be adjusted according to actual needs.

[0058] As shown in FIG. 1, Figures 2-5 The embodiment of the present application also provides a device 300 for in-situ expansion of a sewage treatment system for improving the separation solid flux of a secondary settling tank, which comprises a first-stage separation unit 100 and a second-stage separation unit 200.

[0059] The first-stage separation unit 100 has a first separation chamber 12, and a first feed inlet 14, a first underflow outlet 15 and a first overflow outlet 16 communicating with the first separation chamber 12, the first feed inlet 14 is arranged to communicate with the secondary sedimentation tank 6 of the sewage treatment system, and the first-stage separation unit 100 is arranged to separate the activated sludge input into the first separation chamber 12 from the first feed inlet 14 through spiral motion.

[0060] The second-stage separation unit 200 has a second separation chamber 13, and a second feed inlet 17, a second underflow outlet 18 and a second overflow outlet 19 communicating with the second separation chamber 13, and one of the first overflow outlet 16 and the first underflow outlet 15 communicates with the second feed inlet 17, and the second-stage separation unit 200 is arranged to separate the activated sludge input into the second separation chamber 13 from the second feed inlet 17 through spiral motion, and one of the second overflow outlet 19 and the second underflow outlet 18 is arranged to communicate with the biochemical treatment unit 5 of the sewage treatment system.

[0061] In the in-situ capacity expansion device 300 of the sewage treatment system, the first overflow outlet 16 or the first underflow outlet 15 of the first-stage separation unit 100 can communicate with the second feed inlet 17 of the second-stage separation unit 200, so that the first-stage separation unit 100 and the second-stage separation unit 200 are connected in series.

[0062] When the in-situ capacity expansion device 300 of the sewage treatment system is working, the activated sludge in the secondary sedimentation tank 6 can be input into the first separation chamber 12 of the first-stage separation unit 100 from the first feed inlet 14, and the activated sludge can perform spiral motion in the first separation chamber 12 to separate the activated sludge and discharge the activated sludge from the first underflow outlet 15 and the first overflow outlet 16, respectively.

[0063] As shown in FIG. 1, the activated sludge discharged from the first underflow outlet 15 can be input into the second separation chamber 13 of the second-stage separation unit 200 from the second feed inlet 17, and can perform spiral motion in the second separation chamber 13 to separate the activated sludge and discharge the activated sludge from the second overflow outlet 19 and the second underflow outlet 18, respectively. Figure 3 As shown in FIG. 2, the activated sludge discharged from the first overflow outlet 16 can be input into the second separation chamber 13 of the second-stage separation unit 200 from the second feed inlet 17, and can perform spiral motion in the second separation chamber 13 to separate the activated sludge and discharge the activated sludge from the second overflow outlet 19 and the second underflow outlet 18, respectively. Figure 5

[0064] ​The activated sludge discharged from the second overflow port 19 and the second underflow port 18 has different performance parameters. According to the parameters of the secondary sedimentation tank 6 and the performance of the activated sludge in the aeration tank of the biochemical treatment unit 5, the activated sludge discharged from the second overflow port 19 or the second underflow port 18 of the second separation unit 200 can be returned to the biochemical treatment unit 5 to improve the settling performance of the activated sludge in the aeration tank of the biochemical treatment unit 5, improve the solid separation flux of the secondary sedimentation tank 6, increase the ability of the sewage treatment system to resist hydraulic fluctuation impact, and realize in-situ expansion of the sewage treatment system.

[0065] In some exemplary embodiments, as shown in Figures 2-5 The sewage treatment system in-situ expansion device 300 further comprises an outer cylinder 1, a first inner cone 2 and a second inner cone 3.

[0066] The outer cylinder 1 is provided with a partition to divide the space in the outer cylinder 1 into a first separation chamber 12 and a second separation chamber 13. The outer cylinder 1 can be a cylindrical cylinder. Of course, the outer cylinder 1 can also be a non-cylindrical cylinder.

[0067] The first inner cone 2 is arranged in the first separation chamber 12, and the small end of the first inner cone 2 faces the side where the first feed port 14 and the first overflow port 16 are located. The first underflow port 15 is close to the large end of the first inner cone 2.

[0068] The second inner cone 3 is arranged in the second separation chamber 13, and the small end of the second inner cone 3 faces the side where the second feed port 17 and the second overflow port 19 are located. The second underflow port 18 is close to the large end of the second inner cone 3.

[0069] As shown in Figures 2-5 When the sewage treatment system in-situ expansion device 300 works, the activated sludge enters the first separation chamber 12 through the first feed port 14 and spirally moves in the first separation chamber 12. The activated sludge rotates in the first separation chamber 12 to generate a spiral flow. Under the action of the first inner cone 2, the spiral flow is divided into two parts. One part of the spiral flow (such as the outer spiral flow shown as M1 in Figure 3 and Figure 5 moves to the direction of the first underflow port 15 and is discharged from the first underflow port 15. The other part of the spiral flow (such as the inner spiral flow shown as M2 in Figure 3 and Figure 5 moves to the direction of the first overflow port 16 and is discharged from the first overflow port 16. In the first separation chamber 12, the outer spiral flow M1 and the inner spiral flow M2 exist at the same time to realize the separation of the activated sludge.

[0070] As shown in Figure 2 and Figure 3As shown, after primary separation in the first-stage separation unit 100, the activated sludge discharged from the first underflow outlet 15 enters the second separation chamber 13 through the second inlet 17, where it undergoes a spiral motion. The activated sludge rotates within the second separation chamber 13, generating a spiral flow. Under the action of the second inner cone 3, this spiral flow is divided into two parts: one part is the spiral flow (such as...) Figure 3 The external spiral flow (as shown in M3) moves towards the second underflow port 18 and is discharged from the second underflow port 18, while another part of the spiral flow (such as...) Figure 3 The internal spiral flow (M4) moves towards the second overflow port 19 and is discharged from the second overflow port 19. In the second separation chamber 13, the external spiral flow M3 and the internal spiral flow M4 exist simultaneously to achieve the further separation of activated sludge.

[0071] Or, such as Figure 4 and Figure 5 As shown, after primary separation in the first-stage separation unit 100, the activated sludge discharged from the first overflow port 16 enters the second separation chamber 13 through the second inlet port 17, where it undergoes spiral motion. The activated sludge rotates within the second separation chamber 13, generating a spiral flow. Under the action of the second inner cone 3, this spiral flow is divided into two parts: one part is the spiral flow (such as...) Figure 5 The external spiral flow (as shown in M3) moves towards the second underflow port 18 and is discharged from the second underflow port 18, while another part of the spiral flow (such as...) Figure 5 The internal spiral flow (M4) moves towards the second overflow port 19 and is discharged from the second overflow port 19. In the second separation chamber 13, the external spiral flow M3 and the internal spiral flow M4 exist simultaneously to achieve the further separation of activated sludge.

[0072] After two stages of separation by the first-stage separation unit 100 and the second-stage separation unit 200, the activated sludge discharged from the second underflow port 18 or the second overflow port 19 of the second-stage separation unit 200 can be returned to the biochemical treatment unit 5 as needed.

[0073] In some embodiments, such as Figure 2 and Figure 3 As shown, the separator includes a spiral body 4, which includes a cylindrical part 41 and a spiral blade 42. The spiral blade 42 is disposed between the outer wall surface of the cylindrical part 41 and the inner wall surface of the outer cylinder 1 to form a spiral flow channel 43. The inlet of the spiral flow channel 43 is connected to the first bottom flow port 15, and the outlet of the spiral flow channel 43 is connected to the second feed port 17.

[0074] The partition in the outer cylinder 1 comprises a spiral body 4, which has an annular cavity between the cylindrical part 41 and the inner side wall surface of the outer cylinder 1, the annular cavity is divided into a spiral flow channel 43 by the spiral blade 42, the inlet of the spiral flow channel 43 is communicated with the first bottom flow port 15, and the outlet of the spiral flow channel 43 is communicated with the second feeding port 17, so that the activated sludge discharged from the first bottom flow port 15 firstly enters the spiral flow channel 43 to make spiral motion, and then enters the second separation cavity 13 from the second feeding port 17, so that the activated sludge realizes spiral separation in the second separation cavity 13.

[0075] In some embodiments, as shown in Figure 2 and Figure 3 , the cylindrical part 41 is provided with a first communication cavity 411, the first inner cone 2 comprises a first conical section 21, the cylindrical part 41 is arranged at the large end of the first conical section 21, the first conical section 21 is provided with a second communication cavity 211, the outer cylinder 1 is provided with a discharge port 110, the second overflow port 19 is arranged at one end of the cylindrical part 41 away from the first inner cone 2, and the second overflow port 19, the first communication cavity 411, the second communication cavity 211 and the discharge port 110 are sequentially communicated. Among them, the first conical section 21 and the second communication cavity 211 in it can be conical, and the cylindrical part 41 and the first communication cavity 411 in it can be cylindrical.

[0076] The cylindrical part 41 of the spiral body 4 is arranged at the large end of the first conical section 21 of the first inner cone 2, and the cylindrical part 41 and the first conical section 21 are respectively provided with the first communication cavity 411 and the second communication cavity 211, and the second overflow port 19 is arranged on the cylindrical part 41 of the spiral body 4, and the second overflow port 19 can be communicated with the discharge port 110 on the outer cylinder 1 through the first communication cavity 411 and the second communication cavity 211, so that the sludge overflowing from the second overflow port 19 is discharged from the discharge port 110 after passing through the first communication cavity 411 and the second communication cavity 211.

[0077] In some embodiments, as shown in Figure 2 and Figure 3 , the first overflow port 16 and the discharge port 110 are both arranged on the first end wall 11 of the outer cylinder 1 opposite to the small end of the first conical section 21, and the first overflow port 16 is arranged outside the discharge port 110. Among them, the first end wall 11 can be the upper end wall of the outer cylinder 1, and the small end of the first conical section 21 faces upward.

[0078] The first overflow port 16 is arranged outside the discharge port 110, which is compact, which is beneficial to reduce the size of the first end wall 11, and facilitates the sludge discharged from the first overflow port 16 and the second overflow port 19 to be discharged into the sludge thickening tank together when the settling performance of the activated sludge in the aeration tank in the biochemical treatment unit 5 is not lower than the set settling performance under the high solid load of the secondary sedimentation tank 6.

[0079] Of course, the discharge outlet 110 and the first overflow outlet 16 surrounding the outside of the discharge outlet 110 can also be connected to different pipelines to discharge the sludge discharged by the first overflow outlet 16 and the second overflow outlet 19 into the sludge concentration tank and the biochemical treatment unit 5, respectively.

[0080] In some embodiments, as shown in Figure 2 and Figure 3 The second inner cone 3 includes a second conical section 31 and a second cylindrical section 32, the small end of the second conical section 31 is directed towards the partition, one end of the second cylindrical section 32 is connected to the large end of the second conical section 31, and the other end of the second cylindrical section 32 is connected to the second end wall 111 of the outer cylinder 1, which is arranged opposite to the first end wall 11. The second conical section 31 can be a circular cone, and the second cylindrical section 32 can be a circular cylinder.

[0081] The first feed inlet 14 and the second underflow outlet 18 are both arranged on the side wall of the outer cylinder 1, and the first feed inlet 14 is close to the first end wall 11 of the outer cylinder 1, and the second underflow outlet 18 is close to the second end wall 111 of the outer cylinder 1.

[0082] In the in-situ expansion device 300 of the sewage treatment system, the first inner cone 2, the partition, and the second inner cone 3 can be arranged in sequence from top to bottom, and the small ends of the first inner cone 2 and the second inner cone 3 are both directed upwards. The first feed inlet 14 can be located at the upper part of the side wall of the outer cylinder 1, the first overflow outlet 16 and the discharge outlet 110 are both arranged on the upper end wall (the first end wall 11) of the outer cylinder 1, and the second underflow outlet 18 can be located at the lower part of the side wall of the outer cylinder 1 and close to the second end wall 111 (which can be a lower end wall) of the outer cylinder 1.

[0083] The in-situ expansion device 300 of the sewage treatment system has the advantages of simple and compact structure, small footprint, high screening efficiency, and low operation and maintenance cost, and does not need to add chemicals, thereby realizing the low-consumption high-efficiency secondary sedimentation tank 6 operation performance enhancement technology.

[0084] In some embodiments, as shown in Figure 2 The size of the in-situ expansion device 300 of the sewage treatment system satisfies at least one of the following conditions:

[0085] The inner diameter D of the outer cylinder 1 is: 50mm≤D≤250mm;

[0086] The diameter d of the first feed inlet 14 is: d≤0.25D;

[0087] The diameter O1 of the first overflow outlet 16 is: O1≤0.25D, and the diameter O2 of the second overflow outlet 19 is: O2≤0.25D;

[0088] One end of the first overflow port 16 extends into the first separation chamber 12, and the length l1 of the extension into the first separation chamber 12 is: 0.4D≤l1≤0.8D. One end of the second overflow port 19 extends into the second separation chamber 13, and the length l2 of the extension into the second separation chamber 13 is: 0.4D≤l2≤0.8D.

[0089] The diameter U2 of the second underflow port 18 is: U2≤0.15D.

[0090] The diameter F of the discharge port 110 is: F≥O2.

[0091] The distance L1 between the first end wall 11 of the outer cylinder 1 and the large end of the first conical section 21 is: 3.0D≤L1≤6.0D. The distance L2 between the partition and the large end of the second conical section 31 is: 3.0D≤L2≤6.0D.

[0092] The diameter D1 of the large end of the first conical section 21 is: D1≤0.80D. The diameter D2 of the large end of the second conical section 31 is: D2≤0.80D.

[0093] The height h1 of the first conical section 21 is: 2.0D≤h1≤3.5D. The height h2 of the second conical section 31 is: 2.0D≤h2≤3.5D. The height G2 of the second cylindrical section 32 is: 0.5D2≤G2≤1.5D2.

[0094] The conical angle θ1 of the first conical section 21 is: 16°≤θ1≤24°. The conical angle θ2 of the second conical section 31 is: 16°≤θ2≤24°.

[0095] The number of turns of the helical blade 42 is: 2-6.

[0096] The helical angle β of the helical blade 42 is: 0°≤β≤30°.

[0097] The outer diameter of the cylindrical portion 41 is set to be equal to the diameter D1 of the large end of the first conical section 21.

[0098] Of course, the dimensions of the sewage treatment system in-situ expansion device 300 are not limited to the above ranges, and can be adjusted according to actual needs.

[0099] It should be understood that the "diameter" described above can refer to the diameter of each component, structure, etc. in the case of a cylindrical or circular shape, or can refer to the equivalent diameter of each component, structure, etc. in the case of a non-cylindrical or non-circular shape.

[0100] In other embodiments, for example, Figure 4 and Figure 5As shown, the partition includes a spiral body 4, the spiral body 4 includes a cylindrical part 41 and spiral blades 42, the spiral blades 42 are arranged between the outer sidewall surface of the cylindrical part 41 and the inner sidewall surface of the outer cylinder 1 to form a spiral flow channel 43, the inlet of the spiral flow channel 43 is communicated with the first overflow port 16, and the outlet of the spiral flow channel 43 is communicated with the second feeding port 17.

[0101] The partition in the outer cylinder 1 includes a spiral body 4, the cylindrical part 41 of the spiral body 4 and the inner sidewall surface of the outer cylinder 1 have an annular cavity, the annular cavity is divided into a spiral flow channel 43 by the spiral blades 42, and the inlet of the spiral flow channel 43 is communicated with the first overflow port 16, and the outlet of the spiral flow channel 43 is communicated with the second feeding port 17, so that the activated sludge discharged from the first overflow port 16 first enters the spiral flow channel 43 to make spiral motion, and then enters the second separation cavity 13 from the second feeding port 17, so that the activated sludge realizes spiral separation in the second separation cavity 13.

[0102] In other embodiments, as shown in Figure 4 and Figure 5 shown, the cylindrical part 41 is provided with a first communication cavity 411, the outer cylinder 1 is provided with a discharge port 110, and the second overflow port 19 is arranged on the cylindrical part 41 and communicated with the discharge port 110 through the first communication cavity 411.

[0103] The cylindrical part 41 of the spiral body 4 is provided with a first communication cavity 411, and the second overflow port 19 can be communicated with the discharge port 110 on the outer cylinder 1 through the first communication cavity 411, so that the sludge overflowing from the second overflow port 19 is discharged from the discharge port 110 after passing through the first communication cavity 411.

[0104] In other embodiments, as shown in Figure 4 and Figure 5 shown, the first inner cone 2 includes a first conical section 21 and a first cylindrical section 22, the small end of the first conical section 21 is directed to the partition, one end of the first cylindrical section 22 is connected with the large end of the first conical section 21, and the other end of the first cylindrical section 22 is connected with the second end wall 111 of the outer cylinder 1; the second inner cone 3 includes a second conical section 31 and a second cylindrical section 32, the small end of the second conical section 31 is directed to the partition, one end of the second cylindrical section 32 is connected with the large end of the second conical section 31, and the other end of the second cylindrical section 32 is connected with the first end wall 11 of the outer cylinder 1, and the first end wall 11 and the second end wall 111 of the outer cylinder 1 are arranged opposite to each other. Wherein, the first conical section 21 and the second conical section 31 can be conical, and the first cylindrical section 22 and the second cylindrical section 32 can be cylindrical; the first end wall 11 and the second end wall 111 of the outer cylinder 1 can be upper end wall and lower end wall respectively.

[0105] The first feed inlet 14, the first underflow outlet 15, and the second underflow outlet 18 are all located on the side wall of the outer cylinder 1. The first feed inlet 14 and the discharge outlet 110 are both close to the separator and are arranged opposite to each other. The first underflow outlet 15 is close to the second end wall 111 of the outer cylinder 1, and the second underflow outlet 18 is close to the first end wall 11 of the outer cylinder 1.

[0106] In the in-situ expansion device 300 of the wastewater treatment system, the second inner cone 3, the partition, and the first inner cone 2 can be arranged sequentially from top to bottom, with the small end of the first inner cone 2 facing upwards and the small end of the second inner cone 3 facing downwards. The small ends of both the first inner cone 2 and the second inner cone 3 face the partition wall, so that the first inner cone 2 and the second inner cone 3 can be arranged in a basically symmetrical manner. The first inlet 14 and the outlet 110 can be located in the middle of the side wall of the outer cylinder 1 and are arranged opposite each other; the first underflow outlet 15 can be located in the lower part of the side wall of the outer cylinder 1 and close to the lower end wall (second end wall 111) of the outer cylinder 1; the second underflow outlet 18 can be located in the upper part of the side wall of the outer cylinder 1 and close to the upper end wall (first end wall 11) of the outer cylinder 1.

[0107] The in-situ expansion device 300 for the wastewater treatment system has a simple and compact structure, small size, and low cost.

[0108] In other embodiments, such as Figure 4 As shown, the dimensions of the in-situ expansion device 300 for the wastewater treatment system satisfy at least one of the following:

[0109] The inner diameter D of the outer cylinder 1 is: 50mm≤D≤250mm;

[0110] The diameter d of the first feed inlet 14 is: d≤0.25D;

[0111] The diameter O1 of the first overflow port 16 is: O1≤0.25D, and the diameter O2 of the second overflow port 19 is: O2≤0.25D;

[0112] One end of the first overflow port 16 extends into the first separation chamber 12, and the length l1 extending into the first separation chamber 12 is: 0.4D≤l1≤0.8D; one end of the second overflow port 19 extends into the second separation chamber 13, and the length l2 extending into the second separation chamber 13 is: 0.4D≤l2≤0.8D.

[0113] The diameter U1 of the first underflow outlet 15 is: U1≤0.15D, and the diameter U2 of the second underflow outlet 18 is: U2≤0.15D;

[0114] The diameter F of the discharge port 110 is: F≥O2;

[0115] The distance L1 between the partition and the large end of the first tapered section 21 is 3.0D≤L1≤6.0D, and the distance L2 between the partition and the large end of the second tapered section 31 is 3.0D≤L2≤6.0D;

[0116] The diameter D1 of the large end of the first tapered section 21 is D1≤0.80D, and the diameter D2 of the large end of the second tapered section 31 is D2≤0.80D;

[0117] The height h1 of the first tapered section 21 is 2.0D≤h1≤3.5D, and the height h2 of the second tapered section 31 is 2.0D≤h2≤3.5D;

[0118] The taper angle θ1 of the first tapered section 21 is 16°≤θ1≤24°, and the taper angle θ2 of the second tapered section 31 is 16°≤θ2≤24°;

[0119] The height G1 of the first cylindrical section 22 is 0.5D1≤G1≤1.5D1, and the height G2 of the second cylindrical section 32 is 0.5D2≤G2≤1.5D2;

[0120] The number of turns of the spiral blade 42 is 2-6;

[0121] The spiral angle β of the spiral blade 42 is 0°≤β≤30°;

[0122] The outer diameter N of the cylindrical part 41 is N≤0.80D.

[0123] Of course, the dimensions of the sewage treatment system in-situ expansion device 300 are not limited to the above ranges, and can be adjusted according to actual needs.

[0124] It should be understood that the "diameter" mentioned above can refer to the diameter of each component, structure, etc. in the case of cylindrical or circular shape, or the equivalent diameter in the case of non-cylindrical or non-circular shape.

[0125] In some example embodiments, as shown in Figures 2-5 The first feed inlet 14 is tangential to the first separation cavity 12, so that the activated sludge forms a spiral motion in the first separation cavity 12, achieving separation of the activated sludge.

[0126] Of course, the first feed inlet 14 and the first separation cavity 12 can also be arranged to be not tangential, but to achieve the spiral motion of the activated sludge in the first separation cavity 12 by arranging a spiral flow channel (such as the spiral flow channel 43 in the second separation cavity 13) in the first separation cavity 12.

[0127] In some example embodiments, as shown in Figure 2 and Figure 3As shown, the second underflow port 18 can be tangentially arranged with the second separation chamber 13, the axis of the first overflow port 16 and the discharge port 110 can be coincident, i.e. the first overflow port 16 and the discharge port 110 can be coaxially arranged; or, as shown in Figure 4 and Figure 5 As shown, the first underflow port 15 and the second underflow port 18 can be tangentially arranged with the first separation chamber 12 and the second separation chamber 13 respectively.

[0128] In some example embodiments, the in-situ capacity expansion device 300 of the sewage treatment system further comprises a delivery pump (not shown), the outlet of the delivery pump is connected with the first feed port 14, and the delivery pump is arranged such that the pressure of the activated sludge input into the first feed port 14 is 0.2 MPa to 0.5 MPa. Wherein, the delivery pump device for applying working pressure to the activated sludge can be a submersible pump, a rotor pump or other mechanical device for delivering fluid.

[0129] In some example embodiments, each discharge port (such as the first overflow port 16, the second underflow port 18 and the discharge port 110 in Figure 2 and Figure 3 or the first underflow port 15, the second underflow port 18 and the discharge port 110 in Figure 4 and Figure 5 of the in-situ capacity expansion device 300 of the sewage treatment system is equipped with an electric valve to realize the adjustment of the sludge discharge flow.

[0130] In some example embodiments, the material of the in-situ capacity expansion device 300 of the sewage treatment system is cast iron or stainless steel. Of course, according to the actual situation, the in-situ capacity expansion device 300 of the sewage treatment system can also be selected from other materials.

[0131] In some example embodiments, the axis of the outer cylinder 1 can be perpendicular to the horizontal plane to realize the vertical installation of the in-situ capacity expansion device 300 of the sewage treatment system, as shown in Figures 2-5 or the axis of the outer cylinder 1 is arranged to be inclined relative to the horizontal plane to realize the inclined installation of the in-situ capacity expansion device 300 of the sewage treatment system; or the axis of the outer cylinder 1 is parallel to the horizontal plane to realize the horizontal installation of the in-situ capacity expansion device 300 of the sewage treatment system.

[0132] As shown in Figure 6 and Figure 7 The application further provides a sewage treatment system, which comprises a biochemical treatment unit 5, a secondary sedimentation tank 6 and the in-situ capacity expansion device 300 of the secondary sedimentation tank for increasing the solid separation flux of the sewage treatment system according to any one of the above embodiments, and the first feed port 14 of the in-situ capacity expansion device 300 of the sewage treatment system is in communication with the secondary sedimentation tank 6, and one of the second underflow port 18 and the second overflow port 19 of the in-situ capacity expansion device 300 of the sewage treatment system is in communication with the biochemical treatment unit 5.

[0133] The sewage treatment system of the embodiment of the present application can effectively improve the settling performance of the activated sludge in the aeration tank in the biochemical treatment unit 5 by using the in-situ expansion device 300 of the sewage treatment system, improve the solid separation flux of the secondary sedimentation tank 6, increase the ability of the sewage treatment system to resist hydraulic fluctuation impact, and realize in-situ expansion of the sewage treatment system.

[0134] In some embodiments, as shown in Figure 6 The sewage treatment system is an anaerobic-anoxic-aerobic activated sludge system, and the biochemical treatment unit 5 is sequentially provided with an anaerobic zone 51, a first anoxic zone 52, and a first aerobic zone 53. One of the second underflow port 18 and the second overflow port 19 of the in-situ expansion device 300 of the sewage treatment system communicates with the anaerobic zone 51.

[0135] As shown in Figure 6 The sewage treatment system further includes a primary sedimentation tank 8, and the primary sedimentation tank 8, the biochemical treatment unit 5, and the secondary sedimentation tank 6 are sequentially communicated. The biochemical treatment unit 5 is sequentially provided with an anaerobic zone 51, a first anoxic zone 52, and a first aerobic zone 53. A first internal reflux pipeline 71 can be arranged between the first aerobic zone 53 and the first anoxic zone 52. An external reflux pipeline 73 can be arranged between the secondary sedimentation tank 6 and the anaerobic zone 51. The in-situ expansion device 300 of the sewage treatment system can be arranged in the external reflux pipeline 73.

[0136] In another example embodiment, as shown in Figure 7 The sewage treatment system is a two-stage anoxic-aerobic activated sludge system, and the biochemical treatment unit 5 is sequentially provided with a first anoxic zone 52, a first aerobic zone 53, a second anoxic zone 54, and a second aerobic zone 55. One of the second underflow port 18 and the second overflow port 19 of the in-situ expansion device 300 of the sewage treatment system communicates with the first anoxic zone 52.

[0137] As shown in Figure 7 The sewage treatment system further includes a primary sedimentation tank 8, and the primary sedimentation tank 8, the biochemical treatment unit 5, and the secondary sedimentation tank 6 are sequentially communicated. The biochemical treatment unit 5 is sequentially provided with a first anoxic zone 52, a first aerobic zone 53, a second anoxic zone 54, and a second aerobic zone 55. A first internal reflux pipeline 71 can be arranged between the first aerobic zone 53 and the first anoxic zone 52. A second internal reflux pipeline 72 can be arranged between the second aerobic zone 55 and the second anoxic zone 54. An external reflux pipeline 73 can be arranged between the secondary sedimentation tank 6 and the first anoxic zone 52. The in-situ expansion device 300 of the sewage treatment system can be arranged in the external reflux pipeline 73.

[0138] The in-situ expansion device 300 of the sewage treatment system of the embodiment of the present application has good universality and can be applied to the secondary sedimentation tank 6 of the existing municipal sewage treatment system, such as a system using an anaerobic-anoxic-aerobic activated sludge process, a two-stage anoxic-aerobic activated sludge process, and the like, and can improve the operation efficiency of the secondary sedimentation tank 6.

[0139] In some exemplary embodiments, multiple in-situ expansion devices 300 for wastewater treatment systems are provided, and the multiple in-situ expansion devices 300 for wastewater treatment systems are connected in parallel.

[0140] Based on the activated sludge treatment capacity, multiple in-situ expansion units of the wastewater treatment system can be connected in parallel to increase the activated sludge treatment capacity and thus improve the wastewater treatment performance of the wastewater treatment system.

[0141] In some exemplary embodiments, the operating time and frequency of the in-situ expansion device 300 for the wastewater treatment system can be adjusted in conjunction with the parameters of the wastewater treatment system.

[0142] In some exemplary embodiments, the wastewater treatment system may further include a detection device (not shown in the figure), which is configured to detect the operating parameters of the secondary sedimentation tank 6 (e.g., the solids load of the secondary sedimentation tank) and the performance of the activated sludge in the aeration tank of the biological treatment unit 5 (e.g., the settling performance of the activated sludge in the aeration tank). Based on the detection results of the detection device, one of the first underflow port 15 and the first overflow port 16 of the wastewater treatment system in-situ expansion device 300 may be connected to the second inlet port 17, and one of the second underflow port 18 and the second overflow port 19 of the wastewater treatment system in-situ expansion device 300 may be connected to the biological treatment unit 5.

[0143] The following three specific embodiments illustrate the effectiveness of the in-situ expansion method and apparatus for improving the solids separation flux of the secondary sedimentation tank in this application for wastewater treatment systems.

[0144] Example 1:

[0145] like Figure 2 and Figure 3 As shown in the figure, this embodiment provides an in-situ expansion method and device for a wastewater treatment system to improve the solids separation flux in a secondary sedimentation tank, mainly to solve the problem of poor settling properties of activated sludge.

[0146] In the embodiment, the structural parameters of the in-situ capacity expansion device 300 of the sewage treatment system are as follows: the inner diameter D of the outer cylinder 1 is 60 mm; the diameter d of the first feed port 14 is 15 mm; the diameter D1 of the large end of the first conical section 21 is 48 mm, and the diameter D2 of the large end of the second conical section 31 is 44 mm; the diameter O1 of the first overflow port 16 is 14 mm, and the diameter O2 of the second overflow port 19 is 8 mm; the diameter F of the overflow discharge port 110 is 8 mm; the diameter U2 of the second underflow port 18 is 6 mm; the length l1 of the first overflow port 16 extending into the first separation cavity 12 is 40 mm, and the length l2 of the second overflow port 19 extending into the second separation cavity 13 is 35 mm; the length L1 of the first separation cavity 12 is 220 mm, and the length L2 of the second separation cavity 13 is 190 mm; the height h1 of the first conical section 21 is 145 mm, and the height h2 of the second conical section 31 is 125 mm; the conical angle θ1 of the first conical section 21 is 16°, and the conical angle θ2 of the second conical section 31 is 20°; the number of turns of the spiral blade 42 is 4; the spiral angle β of the spiral blade 42 is 10°; and the height G2 of the second cylindrical section 32 is 30 mm.

[0147] In the embodiment, the pressure of the activated sludge input into the first feed port 14 of the first-stage separation unit 100 is 0.3 MPa.

[0148] In the embodiment, the material of the in-situ capacity expansion device 300 of the sewage treatment system is stainless steel.

[0149] In the embodiment, the installation mode of the in-situ capacity expansion device 300 of the sewage treatment system is positive installation.

[0150] In the embodiment, the concentration of the activated sludge input into the first feed inlet 14 of the first separation unit 100 is 6.5 g / L, each discharge outlet of the in-situ capacity expansion device 300 of the sewage treatment system is equipped with an electric valve, the underflow flow rate (the sludge flow rate discharged from the first underflow outlet 15) / overflow flow rate (the sludge flow rate overflowed from the first overflow outlet 16) of the first separation unit 100 is 0.7, and the underflow flow rate (the sludge flow rate discharged from the second underflow outlet 18) / overflow flow rate (the sludge flow rate overflowed from the second overflow outlet 19) of the second separation unit 200 is 0.5. After the original activated sludge (MLVSS / MLSS = 65.68%, SVI (Sludge Volume Index) = 137 mL / g) is treated by the two-stage separation, the MLVSS / MLSS of the sludge discharged into the thickening tank is 68.27%, and the SVI is 154 mL / g; the MLVSS / MLSS of the activated sludge discharged into the biochemical treatment unit 5 is 45.49%, and the SVI is 106 mL / g. According to the results, the SVI value of the activated sludge discharged into the biochemical treatment unit 5 is low, and the inorganic matter content of the activated sludge is high (the inorganic matter can be used as a condensation nucleus), so the settling performance of the activated sludge in the biochemical treatment unit 5 can be effectively improved.

[0151] Embodiment Two

[0152] The embodiment provides an in-situ capacity expansion method and device of a sewage treatment system for improving the solid flux of a secondary sedimentation tank, and mainly solves the problem of high sludge solid load of the secondary sedimentation tank 6.

[0153] As Figure 4 and Figure 5In the embodiment, the structural parameters of the in-situ capacity expansion device 300 of the wastewater treatment system are as follows: the inner diameter D of the outer cylinder 1 is 80 mm; the diameter d of the first feed inlet 14 is 20 mm; the diameter D1 of the large end of the first conical section 21 is 64 mm, and the diameter D2 of the large end of the second conical section 31 is 60 mm; the diameter O1 of the first overflow outlet 16 is 16 mm, and the diameter O2 of the second overflow outlet 19 is 12 mm; the diameter F of the overflow discharge outlet 110 is 20 mm; the diameter U1 of the first underflow outlet 15 is 8 mm, and the diameter U2 of the second underflow outlet 18 is 6 mm; the length l1 of the first overflow outlet 16 extending into the first separation chamber 12 is 55 mm, and the length l2 of the second overflow outlet 19 extending into the second separation chamber 13 is 35 mm; the length L1 of the first separation chamber 12 is 320 mm, and the length L2 of the second separation chamber 13 is 250 mm; the height h1 of the first conical section 21 is 230 mm, and the height h2 of the second conical section 31 is 170 mm; the conical angle θ1 of the first conical section 21 is 16°, and the conical angle θ2 of the second conical section 31 is 20°; the number of turns of the spiral blade 42 is 4; the spiral angle β of the spiral blade 42 is 10°; the outer diameter N of the cylindrical part 41 is 64 mm; the height G1 of the first cylindrical section 22 is 40 mm, and the height G2 of the second cylindrical section 32 is 35 mm.

[0154] In the embodiment, the pressure of the activated sludge input into the first feed inlet 14 of the first separation unit 100 is 0.25 MPa.

[0155] In the embodiment, the material of the in-situ capacity expansion device 300 of the wastewater treatment system is stainless steel.

[0156] In the embodiment, the installation mode of the in-situ capacity expansion device 300 of the wastewater treatment system is the normal mode.

[0157] In the embodiment, the concentration of the activated sludge input into the first feed inlet 14 of the first separation unit 100 is 10.3 g / L, each discharge outlet of the in-situ capacity expansion device 300 of the wastewater treatment system is equipped with an electric valve, the underflow flow rate / overflow flow rate of the first separation unit 100 is 0.2, and the underflow flow rate / overflow flow rate of the second separation unit 200 is 0.2. After the two-stage separation treatment of the original activated sludge (MLVSS / MLSS = 38.28%), the MLVSS / MLSS of the sludge discharged into the thickening tank is 31.22%, and the MLVSS / MLSS of the activated sludge discharged into the biochemical treatment unit 5 is 43.71%. According to the results, the MLVSS / MLSS value of the activated sludge discharged into the biochemical treatment unit 5 is high, and the MLVSS / MLSS value of the sludge discharged into the thickening tank is low, so that the concentration of the activated sludge can be reduced under the condition of the same microbial content of the biochemical treatment unit 5, and the sludge solid load of the secondary sedimentation tank 6 can be gradually reduced.

[0158] Embodiment Three

[0159] The embodiment provides a sewage treatment system in-situ expansion method and device for improving solid flux separation of a secondary sedimentation tank, and mainly solves the problems of poor settling performance of activated sludge and high solid load of the secondary sedimentation tank 6.

[0160] As shown in Figure 4 and Figure 5 In the embodiment, the angle β of the spiral flow channel 43 of the sewage treatment system in-situ expansion device 300 is 8°, and other structural parameters of the sewage treatment system in-situ expansion device 300 are consistent with those in Embodiment Two.

[0161] In the embodiment, the pressure of the activated sludge input into the first feed port 14 of the first-stage separation unit 100 is 0.4 MPa.

[0162] In the embodiment, the material of the sewage treatment system in-situ expansion device 300 is stainless steel.

[0163] In the embodiment, the installation mode of the sewage treatment system in-situ expansion device 300 is positive installation.

[0164] In the embodiment, the concentration of the activated sludge input into the first feed port 14 of the first-stage separation unit 100 is 8.4 g / L, each discharge port of the sewage treatment system in-situ expansion device 300 is equipped with an electric valve, the underflow flow rate / overflow flow rate of the first-stage separation unit 100 is 0.08, and the underflow flow rate / overflow flow rate of the second-stage separation unit 200 is 0.5. The first-stage separation unit 100 mainly removes inorganic sand particles in the activated sludge, and the second-stage separation unit 200 mainly selects and enriches activated sludge with high organic matter content and low SVI. After the original activated sludge (MLVSS / MLSS=45.16%, SVI=128 mL / g) is treated by two-stage separation, the MLVSS / MLSS of the sludge discharged into the thickening tank is 40.53%, and the SVI is 136 mL / g; the MLVSS / MLSS of the activated sludge discharged into the biochemical treatment unit 5 is 47.01%, and the SVI is 109 mL / g. According to the results, the SVI value of the activated sludge discharged into the biochemical treatment unit 5 is low, and the activated sludge has high organic matter content (high microbial share), so the settling performance of the activated sludge can be gradually improved, and the solid load of the secondary sedimentation tank 6 can be reduced.

[0165] In the description of the present application, it needs to be understood that the terms "length", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0166] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features.

[0167] In the description of the present application, the meaning of "a plurality of" is at least two, for example: two, three, etc., unless otherwise explicitly specified and limited.

[0168] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0169] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0170] In the description of the specification, the description using the terms "one embodiment", "some embodiments", "certain embodiments", etc. means that the particular feature, structure, material or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily referred to the same embodiment or example. Also, the particular features, structures, materials or characteristics can be combined in any suitable manner in one or more embodiments or examples. Furthermore, in non-contradictory relation to each other, those skilled in the art can combine and combine the features described in the specification of different embodiments or examples and the features of different embodiments or examples.

[0171] Although the embodiments of the application have been shown and described above, it is to be understood that the above-mentioned embodiments are exemplary and are not to be construed as limiting the application, and those skilled in the art can make changes, modifications, replacements and variations to the above-mentioned embodiments within the scope of the application.

Claims

1. A method for in-situ expansion of a wastewater treatment system to increase the solids separation flux in a secondary sedimentation tank, characterized in that, include: The activated sludge in the secondary sedimentation tank of the wastewater treatment system is fed into the first separation chamber of the first separation unit from the first feed inlet of the first separation unit, so that the activated sludge is separated by spiral motion in the first separation chamber. Based on the operating parameters of the secondary sedimentation tank and the performance of the activated sludge in the aeration tank of the biochemical treatment unit of the sewage treatment system, the activated sludge discharged from one of the first overflow port and the first underflow port of the first-stage separation unit is input into the second separation chamber of the second-stage separation unit through the second feed port, so that the activated sludge is separated by spiral motion in the second separation chamber, and the activated sludge discharged from one of the second overflow port and the second underflow port of the second-stage separation unit is returned to the biochemical treatment unit. The in-situ expansion method for wastewater treatment systems that improves the solids throughput of the secondary sedimentation tank is based on the morphological and density differences between microbial aggregates, silt, and biomass attached to silt in activated sludge. It employs a two-stage separation unit, including a first-stage separation unit and a second-stage separation unit, to perform gradient-level separation of different solid components in the activated sludge. This achieves the adjustment of the performance of the activated sludge, thereby enabling precise control of the settling properties of the activated sludge in the aeration tank of the biochemical treatment unit and the solids load of the secondary sedimentation tank.

2. The in-situ expansion method for a wastewater treatment system to increase the solids separation flux in a secondary sedimentation tank according to claim 1, characterized in that, The operating parameters of the secondary sedimentation tank include the solid load of the secondary sedimentation tank, and the performance of the activated sludge in the aeration tank includes the settling performance of the activated sludge in the aeration tank. Based on the operating parameters of the secondary sedimentation tank and the performance of the activated sludge in the aeration tank of the biochemical treatment unit of the wastewater treatment system, the activated sludge discharged from one of the first overflow outlet and the first underflow outlet of the first-stage separation unit is input into the second separation chamber of the second-stage separation unit through the second inlet, so that the activated sludge is separated by spiral motion within the second separation chamber. The activated sludge discharged from one of the second overflow outlet and the second underflow outlet of the second-stage separation unit is then returned to the aeration tank, including: When the settling performance of the activated sludge in the aeration tank is lower than the set settling performance, and the solid load of the secondary settling tank is not higher than the set solid load, the activated sludge discharged from the first underflow port of the first-stage separation unit is fed into the second separation chamber of the second-stage separation unit through the second inlet of the second-stage separation unit for separation, and the activated sludge discharged from the second underflow port of the second-stage separation unit is returned to the biochemical treatment unit. When the solid load in the secondary sedimentation tank is higher than the set solid load, and the settling performance of the activated sludge in the aeration tank is not lower than the set set settling performance, the activated sludge discharged from the first overflow port of the first-stage separation unit is fed into the second separation chamber of the second-stage separation unit through the second inlet of the second-stage separation unit for separation, and the activated sludge discharged from the second overflow port of the second-stage separation unit is returned to the biochemical treatment unit. When the settling performance of the activated sludge in the aeration tank is lower than the set settling performance, and the solid load of the secondary settling tank is higher than the set solid load, the activated sludge discharged from the first overflow port of the first-stage separation unit is fed into the second separation chamber of the second-stage separation unit through the second inlet of the second-stage separation unit for separation, and the activated sludge discharged from the second underflow port of the second-stage separation unit is returned to the biochemical treatment unit.

3. The in-situ expansion method for a wastewater treatment system to increase the solids separation flux in a secondary sedimentation tank according to claim 1 or 2, characterized in that, The pressure of the activated sludge input to the first inlet of the first-stage separation unit is 0.2 MPa to 0.5 MPa; and / or The in-situ expansion method for the wastewater treatment system to increase the solids separation flux of the secondary sedimentation tank further includes: transporting the activated sludge discharged from the other outlet of the first overflow port and the first underflow port of the first-stage separation unit to the sludge thickening tank, and transporting the activated sludge discharged from the other outlet of the second overflow port and the second underflow port of the second-stage separation unit to the sludge thickening tank.

4. An in-situ expansion device for a wastewater treatment system to increase the solids separation flux in a secondary sedimentation tank, characterized in that, The in-situ expansion method for a wastewater treatment system for increasing the solids separation flux in a secondary sedimentation tank, as described in any one of claims 1 to 3, comprises: The first-stage separation unit includes a first separation chamber, and a first inlet, a first underflow outlet, and a first overflow outlet connected to the first separation chamber. The first inlet is configured to connect to the secondary sedimentation tank of the wastewater treatment system. The first-stage separation unit is configured to separate the activated sludge input into the first separation chamber from the first inlet using a spiral motion. The second-stage separation unit has a second separation chamber, a second inlet, a second underflow outlet, and a second overflow outlet connected to the second separation chamber. One of the first overflow outlet and the first underflow outlet is connected to the second inlet. The second-stage separation unit is configured to separate the activated sludge input into the second separation chamber from the second inlet through a spiral motion. One of the second overflow outlet and the second underflow outlet is connected to the biochemical treatment unit of the wastewater treatment system.

5. The in-situ expansion device for improving the solids separation flux in a secondary sedimentation tank according to claim 4, characterized in that, Also includes: The outer cylinder has an internal partition to divide the space inside the outer cylinder into the first separation chamber and the second separation chamber. A first inner cone is disposed in the first separation chamber, with the small end of the first inner cone facing the side where the first feed inlet and the first overflow outlet are located, and the first bottom outlet is close to the large end of the first inner cone; and The second inner cone is disposed in the second separation chamber, with the small end of the second inner cone facing the side where the second feed inlet and the second overflow outlet are located, and the second bottom outlet is close to the large end of the second inner cone; Wherein, the axis of the outer cylinder is perpendicular to the horizontal plane; or, the axis of the outer cylinder is inclined relative to the horizontal plane; or, the axis of the outer cylinder is parallel to the horizontal plane.

6. The in-situ expansion device for improving the solids separation flux in a secondary sedimentation tank according to claim 5, characterized in that, The separator includes a spiral body, which includes a cylindrical part and spiral blades. The spiral blades are disposed between the outer wall of the cylindrical part and the inner wall of the outer cylinder to form a spiral flow channel. The inlet of the spiral flow channel is connected to the first bottom flow port, and the outlet of the spiral flow channel is connected to the second feed port. The cylindrical part is provided with a first connecting cavity. The first inner cone includes a first conical segment. The cylindrical part is located at the large end of the first conical segment. The first conical segment is provided with a second connecting cavity. The outer cylinder is provided with a discharge port. The second overflow port is located at the end of the cylindrical part away from the first inner cone. The second overflow port, the first connecting cavity, the second connecting cavity and the discharge port are connected in sequence.

7. The in-situ expansion device for improving the solids separation flux in a secondary sedimentation tank according to claim 6, characterized in that, Both the first overflow port and the discharge port are located on the first end wall of the outer cylinder opposite to the small end of the first conical section, and the first overflow port surrounds the outside of the discharge port; The second inner cone includes a second conical section and a second cylindrical section. The small end of the second conical section faces the separator. One end of the second cylindrical section is connected to the large end of the second conical section. The other end of the second cylindrical section is connected to the second end wall of the outer cylinder. The second end wall of the outer cylinder is disposed opposite to the first end wall. The first feed inlet and the second underflow outlet are both located on the side wall of the outer cylinder, with the first feed inlet close to the first end wall of the outer cylinder and the second underflow outlet close to the second end wall of the outer cylinder.

8. The in-situ expansion device for improving the solids separation flux in a secondary sedimentation tank according to claim 7, characterized in that, The dimensions of the in-situ expansion device for the wastewater treatment system meet at least one of the following requirements: The inner diameter D of the outer cylinder is: 50mm≤D≤250mm; The diameter d of the first feed inlet is: d≤0.25D; The diameter O1 of the first overflow port is: O1≤0.25D, and the diameter O2 of the second overflow port is: O2≤0.25D; One end of the first overflow port extends into the first separation chamber, and the length l1 extending into the first separation chamber is: 0.4D≤l1≤0.8D; one end of the second overflow port extends into the second separation chamber, and the length l2 extending into the second separation chamber is: 0.4D≤l2≤0.8D. The diameter U2 of the second bottom outlet is: U2≤0.15D; The diameter F of the discharge port is: F≥O2; The distance L1 between the first end wall of the outer cylinder and the large end of the first conical section is: 3.0D≤L1≤6.0D, and the distance L2 between the separator and the large end of the second conical section is: 3.0D≤L2≤6.0D; The diameter D1 of the large end of the first conical segment is: D1≤0.80D, and the diameter D2 of the large end of the second conical segment is: D2≤0.80D; The height h1 of the first conical segment is: 2.0D≤h1≤3.5D, the height h2 of the second conical segment is: 2.0D≤h2≤3.5D, and the height G2 of the second cylindrical segment is: 0.5D2≤G2≤1.5D2; The cone angle θ1 of the first conical segment is: 16°≤θ1≤24°, and the cone angle θ2 of the second conical segment is: 16°≤θ2≤24°; The spiral blade is wound 2-6 times. The helix angle β of the helical blade is: 0°≤β≤30°; The outer diameter of the cylindrical part is set to be equal to the diameter D1 of the large end of the first conical segment.

9. The in-situ expansion device for improving the solids separation flux in a secondary sedimentation tank according to claim 5, characterized in that, The separator includes a spiral body, which includes a cylindrical portion and spiral blades. The spiral blades are disposed between the outer wall of the cylindrical portion and the inner wall of the outer cylinder to form a spiral flow channel. The inlet of the spiral flow channel is connected to the first overflow port, and the outlet of the spiral flow channel is connected to the second feed port. The cylindrical part is provided with a first connecting cavity, the outer cylinder is provided with a discharge port, the second overflow port is provided in the cylindrical part, and the second overflow port and the discharge port are connected through the first connecting cavity.

10. The in-situ expansion device for improving the solids separation flux in a secondary sedimentation tank according to claim 9, characterized in that, The first inner cone includes a first conical segment and a first cylindrical segment. The small end of the first conical segment faces the separator. One end of the first cylindrical segment is connected to the large end of the first conical segment, and the other end of the first cylindrical segment is connected to the second end wall of the outer cylinder. The second inner cone includes a second conical section and a second cylindrical section. The small end of the second conical section faces the separator. One end of the second cylindrical section is connected to the large end of the second conical section. The other end of the second cylindrical section is connected to the first end wall of the outer cylinder. The first end wall and the second end wall of the outer cylinder are arranged opposite to each other. The first feed inlet, the first underflow outlet, and the second underflow outlet are all located on the side wall of the outer cylinder. The first feed inlet and the discharge outlet are both close to the separator and are arranged opposite to each other. The first underflow outlet is close to the second end wall of the outer cylinder, and the second underflow outlet is close to the first end wall of the outer cylinder.

11. The in-situ expansion device for improving the solids separation flux in a secondary sedimentation tank according to claim 10, characterized in that, The dimensions of the in-situ expansion device for the wastewater treatment system meet at least one of the following requirements: The inner diameter D of the outer cylinder is: 50mm≤D≤250mm; The diameter d of the first feed inlet is: d≤0.25D; The diameter O1 of the first overflow port is: O1≤0.25D, and the diameter O2 of the second overflow port is: O2≤0.25D; One end of the first overflow port extends into the first separation chamber, and the length l1 extending into the first separation chamber is: 0.4D≤l1≤0.8D; one end of the second overflow port extends into the second separation chamber, and the length l2 extending into the second separation chamber is: 0.4D≤l2≤0.8D. The diameter U1 of the first underflow outlet is: U1≤0.15D, and the diameter U2 of the second underflow outlet is: U2≤0.15D; The diameter F of the discharge port is: F≥O2; The distance L1 between the separator and the large end of the first tapered segment is: 3.0D≤L1≤6.0D, and the distance L2 between the separator and the large end of the second tapered segment is: 3.0D≤L2≤6.0D; The diameter D1 of the large end of the first conical segment is: D1≤0.80D, and the diameter D2 of the large end of the second conical segment is: D2≤0.80D; The height h1 of the first conical segment is: 2.0D≤h1≤3.5D, and the height h2 of the second conical segment is: 2.0D≤h2≤3.5D; The cone angle θ1 of the first conical segment is: 16°≤θ1≤24°, and the cone angle θ2 of the second conical segment is: 16°≤θ2≤24°; The height G1 of the first cylindrical segment is: 0.5D1≤G1≤1.5D1, and the height G2 of the second cylindrical segment is: 0.5D2≤G2≤1.5D2; The spiral blade is wound 2-6 times. The helix angle β of the helical blade is: 0°≤β≤30°; The outer diameter N of the cylindrical part is: N≤0.80D.

12. A wastewater treatment system, characterized in that, The system includes a biochemical treatment unit, a secondary sedimentation tank, and an in-situ expansion device for improving the solids separation flux of the secondary sedimentation tank as described in any one of claims 4 to 11. The first inlet of the in-situ expansion device is connected to the secondary sedimentation tank, and one of the second underflow outlet and the second overflow outlet of the in-situ expansion device is connected to the biochemical treatment unit.

13. The wastewater treatment system according to claim 12, characterized in that, The wastewater treatment system employs an anaerobic-anoxic-aerobic activated sludge process. The biological treatment unit sequentially comprises an anaerobic zone, a first anoxic zone, and a first aerobic zone. One of the second underflow outlet and the second overflow outlet of the in-situ expansion device of the wastewater treatment system is connected to the anaerobic zone; or The wastewater treatment system is a two-stage anoxic-aerobic activated sludge process system. The biochemical treatment unit is provided with a first anoxic zone, a first aerobic zone, a second anoxic zone, and a second aerobic zone in sequence. One of the second underflow outlet and the second overflow outlet of the in-situ expansion device of the wastewater treatment system is connected to the first anoxic zone.

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