High-total-nitrogen town sewage treatment device and method

Abstract

The embodiment of the invention provides a high-total-nitrogen town sewage treatment device and method, and relates to the technical field of sewage treatment. The high-total-nitrogen town sewage treatment device comprises an integrated cylindrical tank body, a cross flow device and an online dissolved oxygen meter, the integrated cylindrical tank body is of a vertical layered upwelling structure and is sequentially provided with an aerobic zone, a buffer zone, an anoxic zone I and an anoxic zone II from bottom to top; a water inlet pipe is arranged at the bottom of the aerobic zone, and a microporous aerator, an aeration fan connected with the microporous aerator and a combined filler positioned above the microporous aerator are arranged in the aerobic zone. According to the scheme, the occupied area is saved by more than 50% through the integrated cylindrical tank body, the total nitrogen removal rate is promoted to reach 82.6%-92% through the dissolved oxygen absorption biological filter layer and the cross flow plate I, the carbon source is saved by 20%-30% in the anoxic zone I, the system is kept stable through the elastic filler, and operation and maintenance are more convenient through the spiral-flow type backwashing device.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and more specifically, to a device and method for treating urban wastewater with high total nitrogen. Background Technology

[0002] Urban sewage mainly comes from domestic sewage and industrial wastewater. When the quality of industrial wastewater changes, it can easily cause an increase in the total nitrogen concentration of urban sewage, affecting the quality of the effluent.

[0003] Traditional biological denitrification processes, such as the AO process, face the following core problems in treating wastewater with high total nitrogen: (1) Insufficient carbon source: Denitrification requires sufficient carbon source, and wastewater with low C / N ratio requires a large amount of external carbon source, which is costly. (2) Dissolved oxygen interference: When nitrified liquid is returned to the anoxic zone, it is easy to introduce dissolved oxygen into the aerobic zone, which inhibits the denitrification effect. (3) Poor system stability: It is sensitive to fluctuations in water quality and quantity, which can easily cause the total nitrogen in the effluent to exceed the standard.

[0004] In view of the above problems, there is a need to provide a technology for treating urban wastewater with high total nitrogen to solve these problems. Summary of the Invention

[0005] This application aims to solve at least one of the technical problems existing in the prior art. To this end, this application proposes a high total nitrogen urban wastewater treatment device and method. The high total nitrogen urban wastewater treatment device adopts an integrated cylindrical tank that vertically integrates an aerobic zone, a buffer zone, an anoxic zone one, and an anoxic zone two, and is equipped with a cross-flow device set along the central axis. It does not require independent structures and saves more than 50% of the land area compared with the traditional separate tank process. The dissolved oxygen absorption biological filter layer in the buffer zone can efficiently consume excess dissolved oxygen. The cross-flow plate forms cross-flow and promotes mixing through the angle difference of the water passage holes. The total nitrogen removal rate reaches 82.6%-92%, which is better than the traditional AO method. The anoxic zone one only needs to control the C / N ratio at 4, and the amount of external carbon source added is reduced by 20%-30%. The online dissolved oxygen meter controls DO, and the elastic packing maintains MLSS. The system has strong shock resistance and stable effluent. The cyclone backwashing device automatically washes the packing. The cross-flow plate and other components are easy to inspect and maintain, making operation and maintenance convenient.

[0006] A high total nitrogen urban wastewater treatment device according to an embodiment of this application includes: an integrated cylindrical tank, a cross-flow device, and an online dissolved oxygen meter; the integrated cylindrical tank is a vertically layered upflow structure, and is provided with an aerobic zone, a buffer zone, an anoxic zone one, and an anoxic zone two from bottom to top; The aerobic zone is equipped with an inlet pipe at the bottom and a microporous aerator, an aeration blower connected to the microporous aerator, and a combined packing material located above the microporous aerator. The buffer zone is equipped with a crossflow plate and a dissolved oxygen absorption biofilter layer. The hypoxic zone is equipped with a carbon source dosing pipe and a suspended packing material. The second anoxic zone is equipped with elastic packing material. The upper part of the second anoxic zone is equipped with a water outlet pipe, which is connected to a bypass pipe. A backwash pump is installed on the bypass pipe, and the backwash pump is connected to the lower part of the second anoxic zone through a pipeline. A vortex backwashing device is installed on the pipeline.

[0007] According to some embodiments of this application, the dissolved oxygen absorption biofilter layer is composed of a filter layer frame, a curtain tensioner, and multiple curtain fabrics; the curtain tensioner is welded equidistantly to the upper and lower parts of the filter layer frame; the curtain fabric is laid on the curtain tensioner and tensioned by it, and after tensioning, the vertical axial angle between the curtain fabric and the integrated cylindrical tank body is 4~8°.

[0008] According to some embodiments of this application, the curtain tensioner includes a rotating shaft, a roller shutter, a tensioning ratchet, and a tensioning rod; The rotating shaft and the roller shutter are made of steel pipes of different diameters, which are concentrically welded together. The two sides of the rotating shaft extend out of the roller shutter and are fixed to the filter layer frame. The outer section of the rotating shaft is provided with two tightening holes, and the inner section is equipped with a tightening ratchet. Fabric grooves are formed on the surface of the roller shutter tube; The tightening rod can be inserted into the tightening hole, driving the rotating shaft, the roller shutter and the tightening ratchet to rotate clockwise synchronously. The tightening ratchet is equipped with a locking device to fix the rotation position.

[0009] According to some embodiments of this application, the crossflow device is arranged along the central axis of the integrated cylindrical tank, and the crossflow device includes a crossflow drive motor and a drive shaft, with crossflow plate one and crossflow plate two both connected to the drive shaft.

[0010] According to some embodiments of this application, both the first and second flow deflectors are provided with a connecting flange between them and the drive shaft, and both the first and second flow deflectors are connected to the drive shaft through the connecting flange.

[0011] According to some embodiments of this application, the crossflow plate one and the crossflow plate two have the same structure, and the surfaces of the crossflow plate one and the crossflow plate two are respectively arranged with water passage hole one and water passage hole two.

[0012] According to some embodiments of this application, there are a total of 4 microporous aerators arranged in a square at the bottom of the integrated cylindrical tank, the combined packing is a combination of plastic rings and polyester filament bundles, and the suspended packing is polyethylene suspended balls.

[0013] According to some embodiments of this application, the online dissolved oxygen meter controls the dissolved oxygen concentration in the aerobic zone to be 1.5~2 mg / L and controls the dissolved oxygen concentration in the hypoxic zone to be 0.1~0.5 mg / L.

[0014] According to some embodiments of this application, the swirling backwashing device is used 2-4 times per week; the MLSS in the integrated cylindrical tank is controlled at 3500-6000 mg / L; the cross-flow drive motor has a power of 0.75 kW and a speed of 3-5 rpm. On the other hand, in order to solve the above-mentioned technical problems, according to the embodiments of this application, the present invention also provides a method for treating urban wastewater with high total nitrogen, comprising the following steps: S1. Urban sewage enters the aerobic zone through the inlet pipe. The aeration blower is started, and oxygen is supplied through the microporous aerator. During the sewage rise, it comes into contact with the biofilm on the combined packing material and undergoes a nitrification reaction, converting ammonia nitrogen into nitrate nitrogen. S2. Wastewater enters the buffer zone, where it is blocked by a crossflow plate to form a uniform flow pattern and then passes through a dissolved oxygen absorption biological filter layer, where activated sludge consumes excess dissolved oxygen. S3. Wastewater enters the anoxic zone 1, carbon source is added through the carbon source dosing pipe, the cross-flow device is started, the cross-flow drive motor drives the drive shaft and cross-flow plate 1 and cross-flow plate 2 to rotate to form cross-flow, promote the mixing of wastewater, carbon source and suspended packing, and the denitrification reaction occurs to convert nitrate nitrogen into nitrogen gas. S4. Wastewater enters the second anoxic zone and undergoes a secondary denitrification reaction in contact with the elastic packing material. The elastic packing material traps suspended sludge, and the qualified wastewater is discharged through the effluent pipe. S5. Start the backwash pump at the frequency of the vortex backwash device to backwash the elastic packing; Among them, S1 to S4 monitor the dissolved oxygen concentration through an online dissolved oxygen meter and adjust the air volume of the aeration blower accordingly.

[0015] The beneficial effects of this application are: I. This invention adopts an integrated cylindrical tank with vertically layered design, sequentially integrating an aerobic zone, buffer zone, anoxic zone one, and anoxic zone two from bottom to top. Each functional zone requires no independent structure, achieving physical separation only through internal packing and components. Simultaneously, a cross-flow device is installed along the central axis of the tank, eliminating the need for additional lateral space. Compared to traditional multi-tank denitrification processes, this device reduces the floor space required by more than 50%, making it particularly suitable for urban wastewater treatment plants with limited land, significantly reducing civil engineering investment costs.

[0016] Second, the combined packing material in the aerobic zone of this invention provides ample attachment sites for nitrifying bacteria. Combined with microporous aerators and aeration blowers, it provides stable oxygen supply and can efficiently convert ammonia nitrogen into nitrate nitrogen. The dissolved oxygen absorption biological filter layer in the buffer zone uses high-concentration activated sludge adsorbed by the curtain fabric to quickly consume excess dissolved oxygen in the nitrification liquid flowing out of the aerobic zone, completely avoiding interference of dissolved oxygen with the denitrification reaction in the anoxic zone one, and creating an optimal anaerobic environment for denitrifying bacteria. The cross-flow device drives the drive shaft to rotate through the cross-flow drive motor, causing cross-flow plate one and cross-flow plate two to operate synchronously. The water passage holes one and two of the two cross-flow plates are at a 20° angle difference. When the sewage rises, it forms a strong cross-flow, which forcibly promotes the uniform mixing of suspended packing material, carbon source and nitrification liquid in the anoxic zone one, avoids the "short-flow" phenomenon, and makes the denitrification reaction more complete.

[0017] Third, in traditional processes, excess dissolved oxygen carried by the nitrification liquor in the aerobic zone reacts with the denitrification carbon source, leading to carbon source waste. This invention eliminates this ineffective loss by pre-consuming dissolved oxygen through a dissolved oxygen absorption biological filter layer, allowing all carbon sources to be used for the denitrification reaction. The cross-flow effect formed by cross-flow plates one and two significantly shortens the contact distance between the carbon source and denitrifying bacteria. Combined with the fixation effect of the suspended packing on bacteria, this further improves the carbon source conversion efficiency. Ultimately, this device only needs to control the C / N ratio in the anoxic zone one at 4 to achieve efficient nitrogen removal. Compared with traditional processes, the external carbon source dosage is reduced by 20% to 30%, and the annual operating cost is reduced by more than 15%.

[0018] Fourth, the online dissolved oxygen meter installed on one side wall of the aerobic and anoxic zones of this invention can monitor the dissolved oxygen concentration in real time and adjust the operating frequency of the aeration blower in conjunction with the aerobic zone to ensure that the DO in the aerobic zone is stable at 1.5~2 mg / L and the DO in the anoxic zone is stable at 0.1~0.5 mg / L, avoiding abnormal dissolved oxygen caused by fluctuations in water quality and quantity, and providing a stable living environment for the microbial community; the elastic packing in the second anoxic zone can effectively intercept suspended sludge carried in the sewage, so that the concentration of suspended solids in the mixed liquor in the integrated cylindrical tank is stably maintained at 3500~6000 mg / L, which greatly improves the system's tolerance to pollutants; at the same time, the backwash pump and the cyclone backwashing device regularly flush the elastic packing to prevent the packing from clogging, further ensuring the long-term stable operation of the system. Even in the face of total nitrogen fluctuations caused by the mixing of industrial sewage, the total nitrogen in the effluent can still be stably controlled below 6 mg / L.

[0019] V. The crossflow plate 1 and crossflow plate 2 of this invention are installed in the lower slot and, together with the roller seat and the limiting roller, can be easily pulled out and disassembled for easy cleaning or replacement; the curtain tensioner of the dissolved oxygen absorption biological filter layer achieves rapid tensioning and replacement of the curtain fabric through the rotating shaft, the roller shutter, and the tensioning rod, without disassembling the entire filter layer frame, thus improving maintenance efficiency by 40%; the vortex backwashing device can set the flushing frequency according to the blockage of the elastic packing, and automatically extracts the qualified production water from the water pipe for flushing through the backwashing pump, without the need for an external flushing water source, and the flushing process does not affect the main treatment process, reducing manual intervention and lowering the labor intensity of maintenance personnel.

[0020] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a high total nitrogen urban wastewater treatment technology according to the present invention; Figure 2 This is a plan view of the microporous aerator of the present invention; Figure 3 This is a structural diagram of the dissolved oxygen absorption biofilter layer of the present invention; Figure 4 This is a structural diagram of the curtain tensioner of the present invention; Figure 5 This is an enlarged schematic diagram of a partial structure of the curtain tensioner of the present invention; Figure 6 This is a perspective view of the fabric tensioner and filter layer frame of the present invention being fixed together. Figure 7 This is a structural diagram of the crossflow device of the present invention; Figure 8 This is an enlarged schematic diagram of the connection point between the crossflow plate 2 and the device. Figure 9 This is a longitudinal structural cross-sectional view of the crossflow device of the present invention; Figure 10 This is a schematic diagram of a crossflow plate of the present invention; Figure 11 This is an enlarged schematic diagram of the second projection surface of the crossflow plate of the present invention; Icons: 1. Integrated cylindrical tank; 2. Aerobic zone; 3. Inlet pipe; 4. Aeration blower; 5. Microporous aerator; 6. Combined packing material; 7. Buffer zone; 8. Cross-flow drive motor; 810. Cross-flow plate one; 820. Cross-flow plate two; 9. Dissolved oxygen absorption biological filter layer; 10. Anoxic zone one; 11. Suspended packing material; 12. Anoxic zone two; 13. Elastic packing material; 14. Outlet pipe; 15. Backwash pump; 16. Swirl-type backwashing device; 17. Online dissolved oxygen meter 18. Carbon source dosing pipe; 801. Drive shaft; 802. Mounting base; 803. Connecting flange; 804. Lower slot; 805. Roller seat; 806. Limiting roller; 807. Water passage hole two; 808. Water passage hole one; 901. Filter layer frame; 902. Curtain tensioner; 903. Curtain fabric; 904. Rotating shaft; 905. Roller shutter cylinder; 906. Fabric slot; 907. Tensioning hole; 908. Tensioning ratchet; 909. Tensioning rod. Detailed Implementation

[0023] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0024] The method for treating high total nitrogen urban wastewater according to embodiments of this application includes the following steps: S1. Urban sewage enters the aerobic zone 2 through the inlet pipe 3. The aeration blower 4 is started and oxygen is supplied through the microporous aerator 5. During the sewage rise, it comes into contact with the biofilm on the combined packing material 6 and undergoes a nitrification reaction, converting ammonia nitrogen into nitrate nitrogen. S2. Wastewater enters the buffer zone 7, where it is blocked by the crossflow plate 810 to form a uniform flow pattern and then passes through the dissolved oxygen absorption biological filter layer 9, where the activated sludge consumes the excess dissolved oxygen. S3. Wastewater enters the anoxic zone 10 and carbon source is added through carbon source dosing pipe 18. The cross-flow device is activated. The cross-flow drive motor 8 drives the drive shaft 801 and cross-flow plate 810 and cross-flow plate 820 to rotate and form cross-flow, which promotes the mixing of wastewater, carbon source and suspended packing 11, and the denitrification reaction is carried out to convert nitrate nitrogen into nitrogen gas. S4. Wastewater enters the anoxic zone 12 and comes into contact with the elastic packing material 13 to carry out a secondary denitrification reaction. The elastic packing material 13 intercepts suspended sludge, and the qualified wastewater is discharged through the effluent pipe 14. S5. Start the backwash pump 15 at the frequency of the swirl backwash device 16 to backwash the elastic packing 13; Among them, S1 to S4 monitor the dissolved oxygen concentration through the online dissolved oxygen meter 17 and adjust the air volume of the aeration blower 4 accordingly.

[0025] like Figures 1-11As shown in the embodiment of this application, a high total nitrogen urban wastewater treatment device includes an integrated cylindrical tank 1, a cross-flow device, and an online dissolved oxygen meter 17. The integrated cylindrical tank 1 has a vertical layered upflow structure, and is provided with an aerobic zone 2, a buffer zone 7, an anoxic zone one 10, and an anoxic zone two 12 from bottom to top. The buffer zone 7 is located on the side opposite to the aerobic zone 2 and the anoxic zone one 10. The anoxic zone two 12 is located above the anoxic zone one 10. The aerobic zone 2 has an inlet pipe 3 at the bottom, and a microporous aerator 5, an aeration blower 4 connected to the microporous aerator 5, and a combined packing material 6 located above the microporous aerator 5 are provided in the aerobic zone 2. like Figure 2 As shown, there are four microporous aerators 5, arranged in a square at the bottom of the integrated cylindrical tank 1, and connected to the aeration blower 4 outside the integrated cylindrical tank 1 through a pipe; the combined packing 6 is a combination of plastic rings and polyester filament bundles, and the suspended packing 11 is a polyethylene suspended ball.

[0026] The buffer zone 7 is equipped with a crossflow plate 810 and a dissolved oxygen absorption biofilter layer 9; wherein, the anoxic zone 10 is located above the dissolved oxygen absorption biofilter layer 9. The anoxic zone 10 is equipped with a carbon source dosing pipe 18 and a suspended packing 11. The cross-flow plate 820 is located above the suspended packing 11. The carbon source dosing pipe 18 is located above the buffer zone 7. The excess dissolved oxygen in the aerobic zone 2 is consumed by the buffer zone 7 and then mixed with the carbon source to reduce the inhibition of denitrification by dissolved oxygen and save carbon source.

[0027] Specifically, the carbon source added by carbon source dosing tube 18 is a 20% sodium acetate solution with a COD concentration of 165,000 mg / L. The amount of carbon source added meets the requirement that the C / N ratio in the anoxic zone -10 is controlled at 4.

[0028] The anoxic zone 2 12 is equipped with elastic packing material 13. The upper part of the anoxic zone 2 12 is equipped with a water outlet pipe 14, which is connected to a bypass pipe. The bypass pipe is equipped with a backwash pump 15, which is connected to the lower part of the anoxic zone 2 12 through a pipeline. The pipeline is equipped with a vortex backwashing device 16 to backwash the elastic packing material and prevent clogging.

[0029] Among them, the swirl-type backwashing device 16 is flushed 2 to 4 times a week; the MLSS in the integrated cylindrical tank 1 is controlled at 3500 to 6000 mg / L; the cross-flow drive motor 8 has a power of 0.75 kW and a speed of 3 to 5 rpm.

[0030] Specifically, elastic packing material 13 is installed above the anoxic zone 2 12 to intercept sludge and maintain a high sludge concentration. The packing material is backwashed periodically with the device's permeate. The backwashing is performed using a vortex backwashing device 16, and the backwashing frequency is 2 to 4 times per week, depending on the degree of packing material blockage. Online dissolved oxygen meter 17 is installed on the side wall of aerobic zone 2 and anoxic zone 10 respectively. The operating frequency of aeration fan 4 can be controlled according to dissolved oxygen data.

[0031] The online dissolved oxygen meter 17 controls the dissolved oxygen concentration in the aerobic zone 2 to be 1.5~2 mg / L and controls the dissolved oxygen concentration in the hypoxic zone 10 to be 0.1~0.5 mg / L.

[0032] like Figures 4 to 6 As shown, the dissolved oxygen absorption biological filter layer 9 consists of a filter layer frame 901, a curtain tensioner 902, and multiple curtain fabrics 903. The filter layer frame 901 is a steel structure, and the curtain tensioner 902 is welded equidistantly to the upper and lower parts of the filter layer frame 901. The curtain fabrics 903 are laid on the curtain tensioner 902 and tensioned by it. After tensioning, the curtain fabrics 903 and the integrated cylindrical tank 1 have a vertical axial angle of 4~8°. The curtain fabrics 903 are made of a material that easily adsorbs activated sludge. The curtain fabrics 903 easily adsorb activated sludge, thus forming a high sludge concentration. When the nitrified liquid treated in the aerobic zone enters the dissolved oxygen absorption biological filter layer 9, the dissolved oxygen is quickly consumed, preventing excess dissolved oxygen from entering the anoxic zone 10.

[0033] like Figure 4 As shown, the curtain tensioner 902 includes a rotating shaft 904, a roller shutter 905, a tensioning ratchet 908, and a tensioning rod 909; The rotating shaft 904 and the roller shutter 905 are made of steel pipes of different diameters and are concentrically welded. The rotating shaft 904 extends out of the roller shutter 905 on both sides and is fixed to the filter layer frame 901. The outer section of the rotating shaft 904 is provided with two tightening holes 907, and the inner section is equipped with a tightening ratchet 908. A fabric slot 906 is provided on the surface of the roller shutter 905. The fabric slot 906 is open on the side away from the tightening hole 907 and closed on the side closer to it, so that the curtain fabric 903 can be more easily put into the fabric slot 906. The tightening rod 909 is a movable component. The tightening rod 909 can be inserted into the tightening hole 907, which drives the rotating shaft 904, the roller shutter 905 and the tightening ratchet 908 to rotate clockwise synchronously. The tightening ratchet 908 is equipped with a locking device to fix the rotation position.

[0034] The tensioning rod 909 is a movable component. After the curtain fabric 903 is placed into the fabric slot 906, the tensioning rod 909 is inserted into the tensioning hole 907. The tensioning rod 909 is rotated clockwise, and the tensioning ratchet 908 rotates synchronously and is fixed by the clip, so that the curtain fabric 903 can be tensioned.

[0035] like Figures 7 to 9As shown, the crossflow device is arranged along the central axis of the integrated cylindrical tank 1. The crossflow device includes a crossflow drive 8 and a drive shaft 801. Crossflow plate 1 810 and crossflow plate 2 820 are both connected to the drive shaft 801. The crossflow drive 8 is located above the integrated cylindrical tank 1 and is fixed by bolts. The end of the drive shaft 801 is connected to the output end of the crossflow drive 8, and the bottom of the drive shaft 801 penetrates into the inner cavity of the integrated cylindrical tank 1. The bottom of the drive shaft 801 is movably mounted with a mounting base 802 via a sealed bearing. The mounting base 802 is used to provide auxiliary support for the drive shaft 801 and improve the stability of its support.

[0036] Both the first flow deflector 810 and the second flow deflector 820 are provided with a docking flange 803 between them and the drive shaft 801. Both the first flow deflector 810 and the second flow deflector 820 are connected to the drive shaft 801 through the docking flange 803. Both the first flow deflector plate 810 and the second flow deflector plate 820 are provided with a lower slot 804. The lower slot 804 is an annular steel plate and is welded to the inner wall of the integrated cylindrical tank 1. The lower slot 804 is provided with a limiting roller 806; the limiting roller 806 plays the role of limiting and correcting deviation.

[0037] A roller seat 805 is provided above the limiting roller 806. The roller seat 805 is an annular steel plate and is welded to the inner wall of the integrated cylindrical tank 1. The ring width of the roller seat 805 is smaller than the ring width of the lower slot 804, which facilitates the installation and maintenance of the first flow deflector 810 and the second flow deflector 820.

[0038] In actual use, the flow deflector 1 810 and flow deflector 2 820 make smooth transitions when they come into contact with the limiting roller 806 during rotation, preventing the device from shifting due to disturbances caused by the rising water flow and affecting its dynamic balance.

[0039] like Figure 9 As shown, the cross-flow plate 810 and the cross-flow plate 820 have the same structure, and the surfaces of the cross-flow plate 810 and the cross-flow plate 820 are respectively arranged with water passage holes 808 and water passage holes 807. The water passage holes 808 and water passage holes 807 are arranged with different perimeters based on the center of the cross-flow plate 810 and the cross-flow plate 820, respectively, forming 9 groups of water passage holes, with an included angle of 40° between adjacent groups of water passage holes. The crossflow plate 810 and crossflow plate 820 are installed at different angles, and the angle difference between the flow hole groups is 20°, while the diameter of the water passage hole 808 and the water passage hole 807 is 10mm.

[0040] In actual use, the influent forms cross-flow due to the different angles between the orifice groups during the upward process, and the effect of cross-flow is enhanced by the cross-flow drive motor 8, which promotes the mixing of various substances in the anoxic zone 10.

[0041] The working principle of this high total nitrogen urban wastewater treatment system is as follows: Urban wastewater enters the aerobic zone 2 through the inlet pipe 3, and simultaneously, the aeration blower 4 is activated. The aeration blower 4 oxygenates the aerobic zone 2 through the microporous aerator 5. During the ascent of the integrated cylindrical tank 1, the urban wastewater first passes through the combined packing 6, where it undergoes nitrification with the biofilm on the packing 6, converting ammonia nitrogen into nitrate nitrogen. The urban wastewater then enters the transition zone, i.e., the buffer zone 7, where it first passes through the cross-flow plate 810 to block large air bubbles and form a uniform flow pattern. It then rises through the dissolved oxygen absorption biological filter layer 9, where the high concentration of activated sludge in the filter layer removes excess dissolved oxygen, reducing interference with the denitrification reaction. After exiting the dissolved oxygen absorption biological filter layer 9, the urban wastewater enters the anoxic zone 10, where carbon source is simultaneously added through the carbon source dosing pipe 18. The mixture of wastewater and carbon source rises into the suspended packing 11 and the cross-flow plate 820. The cross-flow plate 820 and the cross-flow plate 810 are configured with different... The water passage holes 807 and 808 are angled and rotated under the action of the cross-flow drive motor 8, forming a cross-flow in the anoxic zone 10, which intensifies the mixing effect of suspended packing 11, sewage and carbon source, and converts nitrate nitrogen into nitrogen gas; the urban sewage finally enters the anoxic zone 12, which is equipped with elastic packing 13. Under anoxic conditions, the remaining carbon source is used for secondary denitrification. The elastic packing 13 can also retain sludge in the permeate, ensuring that the entire process section maintains a high sludge concentration; after secondary denitrification, the urban sewage flows out through the effluent pipe 14. The effluent pipe 14 is equipped with a bypass and connected to a backwash pump 15. The backwash pump 15 is started periodically to backwash the elastic packing 13. The backwash pipe is connected to a vortex backwashing device 16 to prevent the packing from clogging.

[0042] Online dissolved oxygen meters 17 are also installed on the side walls of aerobic zone 2 and anoxic zone 10 to monitor dissolved oxygen in the area and link with aeration fan 4 to adjust the air volume, controlling the dissolved oxygen in aerobic zone 2 to be 1.5~2mg / L and the dissolved oxygen in anoxic zone 10 to be 0.1~0.5mg / L.

[0043] Example 1 In this embodiment, wastewater from the equalization tank of a wastewater treatment plant was used. The main pollutants were CODcr at 80-110 mg / L, ammonia nitrogen at 15-25 mg / L, and total nitrogen at 20-30 mg / L. The high total nitrogen urban wastewater is treated using the technology provided by this invention.

[0044] In this embodiment, the integrated cylindrical tank 1 has a diameter of 12m and a height of 9m, and is vertically layered. The aerobic zone 2 has a height of 2.5m, with four sets of microporous aerators 5 at the bottom and a combined packing material 6 at the top, such as plastic rings paired with polyester filament bundles. The buffer zone 7 has a height of 1.5m, with a cross-flow plate 810 having a pore size of 10mm. The dissolved oxygen absorption biological filter layer 9 is composed of multiple filter elements, each 1.5m long × 1m wide × 1m high, and each element contains eight curtain-type fabrics 903 with an inclination angle of 6°. The anoxic zone 10 has a height of 2.5m, with suspended packing material 11 consisting of polyethylene suspended balls. A cross-flow plate 820 is installed above it, with an angle difference of 20° between the water passage holes 807 of the cross-flow plate 820 and the water passage holes 808 of the cross-flow plate 810. The anoxic zone 12 has a height of 2m and is topped with three-dimensional elastic packing material 13. The cross-flow drive motor 8 of the cross-flow device has a power of 0.75kW and a speed of 3rpm.

[0045] During operation, the frequency of the aeration fan 4 was controlled by the online dissolved oxygen meter 17. The dissolved oxygen in the aerobic zone 2 was approximately 1.8 mg / L, and the dissolved oxygen in the anoxic zone 10 was approximately 0.3 mg / L. After the dissolved oxygen was absorbed by the biological filter layer 9, the dissolved oxygen was reduced by 83%. The external carbon source was a 20% sodium acetate solution with a COD concentration of approximately 165,000 mg / L. By adding sodium acetate, the C / N ratio in the anoxic zone 10 was controlled at 4. During operation, the MLSS in the device was controlled at approximately 3,500 mg / L, and the cyclone backwashing device 16 was run twice a week.

[0046] The concentrations of major pollutants before and after treatment are shown in Table 1. Table 1 shows that the C / N ratio of the urban wastewater influent is 3.7. This device adds a small amount of carbon source to increase the C / N ratio to 4, achieving a total nitrogen removal rate of 82.6%. Conventional AO processes, under the condition of a C / N ratio controlled at 4, achieve a total nitrogen removal rate of approximately 60%. Furthermore, the device's CODCr and ammonia nitrogen removal rates are also superior to those of conventional processes.

[0047] Table 1 - Concentrations of Major Pollutants in Wastewater Treatment Plant Influent and Effluent Example 2 This embodiment uses influent from a food industrial park wastewater treatment plant, where the main pollutants are CODcr (130-200 mg / L), ammonia nitrogen (45-55 mg / L), and total nitrogen (70-85 mg / L). Due to the influence of food wastewater, the influent has a high total nitrogen content and a low C / N ratio. The high total nitrogen urban wastewater treatment technology provided by this invention is used for denitrification.

[0048] For food wastewater quality, in this embodiment, the filter elements of the dissolved oxygen absorption biological filter layer 9 are 2m long × 1m wide × 1m high, each element contains 12 sheets of curtain-type fabric 903, with an inclination angle of 8°, which improves the sludge adsorption concentration and dissolved oxygen absorption efficiency of the dissolved oxygen absorption biological filter layer 9; the cross-flow device's cross-flow drive motor 8 has a power of 0.75kW and a speed of 5rpm; during operation, the MLSS in the device is controlled at around 6000mg / L, and the cyclone backwashing device 16 runs once every 2 days to solve the problem of easy clogging of the packing material caused by sludge carrying grease.

[0049] The concentrations of the main pollutants before and after treatment are shown in Table 2. As can be seen from Table 2, the C / N ratio of the wastewater is 2.07. Adding sodium acetate increases the C / N ratio to 4, and the total nitrogen in the effluent is 6 mg / L, with a total nitrogen removal rate as high as 92%.

[0050] Table 2 - Concentrations of Major Pollutants in the Influent and Effluent of the Wastewater Treatment Plant in the Food Industrial Park The above are merely embodiments of this application and are not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0051] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A high-total-nitrogen urban wastewater treatment device, characterized in that, include: Integrated cylindrical tank (1), cross-flow device and online dissolved oxygen meter (17); the integrated cylindrical tank (1) is a vertical layered upflow structure, and from bottom to top are arranged an aerobic zone (2), a buffer zone (7), an anoxic zone one (10) and an anoxic zone two (12). The aerobic zone (2) is provided with an inlet pipe (3) at the bottom, and a microporous aerator (5), an aeration blower (4) connected to the microporous aerator (5), and a combined packing material (6) located above the microporous aerator (5) are provided in the aerobic zone (2). The buffer zone (7) is provided with a crossflow plate (810) and a dissolved oxygen absorption biofilter layer (9). The anoxic zone 1 (10) is equipped with a carbon source dosing pipe (18) and a suspended packing material (11). The anoxic zone 2 (12) is equipped with elastic packing (13), and the upper part of the anoxic zone 2 (12) is equipped with a water outlet pipe (14). The water outlet pipe (14) is connected to a bypass pipe, and a backwash pump (15) is installed on the bypass pipe. The backwash pump (15) is connected to the lower part of the anoxic zone 2 (12) through a pipeline, and a vortex backwashing device (16) is installed on the pipeline.

2. The high total nitrogen urban wastewater treatment device according to claim 1, characterized in that, The dissolved oxygen absorption biofilter (9) consists of a filter layer frame (901), a curtain tensioner (902), and multiple curtain fabrics (903); the curtain tensioner (902) is welded at equal intervals to the upper and lower parts of the filter layer frame (901); the curtain fabric (903) is laid on the curtain tensioner (902) and tensioned by it, and after tensioning, the vertical axial angle between the curtain fabric (903) and the integrated cylindrical tank (1) is 4~8°.

3. A high total nitrogen urban wastewater treatment device according to claim 2, characterized in that, The curtain tensioner (902) includes a rotating shaft (904), a roller shutter cylinder (905), a tensioning ratchet (908), and a tensioning rod (909). The rotating shaft (904) and the roller shutter (905) are made of steel pipes of different diameters and are concentrically welded. The rotating shaft (904) extends out of the roller shutter (905) on both sides and is fixed to the filter layer frame (901). The outer section of the rotating shaft (904) is provided with two tightening holes (907), and the inner section is equipped with a tightening ratchet (908). Fabric grooves (906) are provided on the surface of the roller shutter tube (905); The tightening rod (909) can be inserted into the tightening hole (907) to drive the rotating shaft (904), the roller shutter (905) and the tightening ratchet (908) to rotate clockwise synchronously. The tightening ratchet (908) is provided with a locking device to fix the rotation position.

4. A high total nitrogen urban wastewater treatment device according to claim 1, characterized in that, The crossflow device is arranged along the central axis of the integrated cylindrical tank (1). The crossflow device includes a crossflow drive (8) and a drive shaft (801). Crossflow plate one (810) and crossflow plate two (820) are both connected to the drive shaft (801).

5. A high total nitrogen urban wastewater treatment device according to claim 4, characterized in that, Both the first flow deflector (810) and the second flow deflector (820) are provided with a docking flange (803) between them and the drive shaft (801). Both the first flow deflector (810) and the second flow deflector (820) are connected to the drive shaft (801) through the docking flange (803).

6. A high total nitrogen urban wastewater treatment device according to claim 5, characterized in that, The cross-flow plate one (810) and cross-flow plate two (820) have the same structure, and the surfaces of cross-flow plate one (810) and cross-flow plate two (820) are respectively arranged with water passage hole one (808) and water passage hole two (807).

7. A high total nitrogen urban wastewater treatment device according to claim 1, characterized in that, There are four microporous aerators (5), which are arranged in a square at the bottom of the integrated cylindrical tank (1). The combined packing (6) is a combination of plastic rings and polyester filament bundles, and the suspended packing (11) is a polyethylene suspended ball.

8. A high total nitrogen urban wastewater treatment device according to claim 1, characterized in that, The online dissolved oxygen meter (17) controls the dissolved oxygen concentration in the aerobic zone (2) to be 1.5~2 mg / L and controls the dissolved oxygen concentration in the hypoxic zone (10) to be 0.1~0.5 mg / L.

9. A high total nitrogen urban wastewater treatment device according to claim 5, characterized in that, The swirling backwashing device (16) is flushed 2 to 4 times per week; the MLSS in the integrated cylindrical tank (1) is controlled at 3500 to 6000 mg / L; the cross-flow drive motor (8) has a power of 0.75 kW and a speed of 3 to 5 rpm.

10. A method for treating urban wastewater with high total nitrogen, comprising the urban wastewater treatment device for high total nitrogen as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Urban sewage enters the aerobic zone (2) through the inlet pipe (3), and the aeration blower (4) is started. Oxygen is supplied through the microporous aerator (5). During the rise of the sewage, it comes into contact with the biofilm on the combined packing material (6) and undergoes a nitrification reaction, converting ammonia nitrogen into nitrate nitrogen. S2. Wastewater enters the buffer zone (7), where it is blocked by the crossflow plate (810) to form a uniform flow pattern, and then passes through the dissolved oxygen absorption biological filter layer (9) to consume excess dissolved oxygen using activated sludge. S3. Wastewater enters the anoxic zone 1 (10), carbon source is added through carbon source dosing pipe (18), cross-flow device is started, cross-flow drive motor (8) drives drive shaft (801) and cross-flow plate 1 (810) and cross-flow plate 2 (820) to rotate to form cross-flow, promote the mixing of wastewater, carbon source and suspended packing (11), and denitrification reaction occurs to convert nitrate nitrogen into nitrogen gas; S4. Wastewater enters the anoxic zone 2 (12) and comes into contact with the elastic packing material (13) to carry out a secondary denitrification reaction. The elastic packing material (13) intercepts suspended sludge, and the qualified wastewater is discharged through the effluent pipe (14). S5. Start the backwash pump (15) at the frequency of the swirl backwash device (16) to backwash the elastic packing (13); Among them, S1 to S4 monitor the dissolved oxygen concentration through an online dissolved oxygen meter (17) and adjust the air volume of the aeration blower (4) accordingly.

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