Integrated autotrophic nitrogen removal device, method and system for sewage treatment

Abstract

This invention belongs to the field of wastewater treatment technology and specifically discloses an integrated autotrophic denitrification device, method, and wastewater treatment system. The device includes a reactor containing, from bottom to top, a short-cut nitrification zone, an anaerobic ammonia oxidation zone, a sulfur autotrophic zone, and a gas chamber. An inclined first partition plate is located at the top of the short-cut nitrification zone, and an inclined second partition plate is located at the bottom of the anaerobic ammonia oxidation zone, forming a gas-sludge-water separation chamber. The reactor contains a vertically extending gas-liquid lifting channel and a sludge-water separation channel surrounding it. A third partition plate is located between the anaerobic ammonia oxidation zone and the sulfur autotrophic zone. The sulfur autotrophic zone contains a clear liquid separation structure, the outlet of which is connected to the bottom of the anaerobic ammonia oxidation zone via a reflux circulation pipe. This invention's device achieves efficient, low-consumption, and stable denitrification of wastewater with high ammonia nitrogen and low carbon-to-nitrogen ratio through self-separation of sludge, water, and gas and self-driven internal circulation. It requires no external carbon source, occupies a small area, has low operating costs, and has broad application prospects.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and specifically relates to an integrated autotrophic denitrification device, method and wastewater treatment system for wastewater treatment. Background Technology

[0002] With the rapid development of industries such as photovoltaics, electronics, and chemicals, their industrial wastewater is characterized by high ammonia nitrogen concentrations, low organic carbon content, high salinity, and large fluctuations in water quality. Nitrogen pollutants discharged into water bodies easily lead to eutrophication and ecological imbalance, becoming a key constraint on achieving compliant industrial wastewater discharge.

[0003] The current mainstream nitrogen removal technology is the traditional nitrification-denitrification process, which has the following shortcomings: high carbon source demand: low carbon-to-nitrogen ratio wastewater requires the addition of large amounts of external carbon sources such as methanol and sodium acetate, resulting in high operating costs and safety risks; high aeration energy consumption: complete nitrification requires maintaining a high dissolved oxygen level, and energy consumption accounts for 30% to 60% of the total energy consumption of the wastewater treatment plant; large sludge production and poor operational stability: heterotrophic bacteria grow rapidly, and problems such as incomplete denitrification are prone to occur under water quality fluctuations.

[0004] To reduce energy and carbon consumption, low-carbon nitrogen removal technologies such as anaerobic ammonia oxidation, short-cut nitrification-denitrification, and sulfur autotrophic denitrification have been developed in recent years. However, these technologies still employ a split-type structure in practical engineering, placing each functional unit in a different reaction tank. This presents the following prominent problems: high civil engineering costs and large land area requirements, hindering land conservation in new projects and the upgrading of old facilities; complex operation and control, requiring independent control of parameters such as dissolved oxygen, sludge age, and hydraulic retention time for each unit, making automation difficult; easy loss of functional bacteria, system instability, and segmented flow leading to interference between various functional bacteria; complex internal recirculation systems with high energy consumption and control delays; and high technical requirements for operators.

[0005] Therefore, there is an urgent need for an integrated denitrification device that is compact in structure, functionally integrated, and stable in operation, so as to achieve the coordinated and efficient operation of short-cut nitrification-denitrification, anaerobic ammonia oxidation and sulfur autotrophic denitrification in a single-stage reactor, in order to solve the above-mentioned problems of existing technologies. Summary of the Invention

[0006] The purpose of this invention is to provide an integrated autotrophic denitrification device, method, and wastewater treatment system for wastewater treatment, addressing at least some of the aforementioned problems in the prior art.

[0007] The first aspect of the present invention provides an integrated autotrophic denitrification device for wastewater treatment, comprising a reactor, wherein the reactor is provided with a short-cut nitrification zone, an anaerobic ammonia oxidation zone, a sulfur autotrophic zone and a gas chamber arranged sequentially from bottom to top; The reactor is provided with an inlet pipe at the bottom that is connected to the short-cut nitrification zone, and an outlet and a water outlet at the top. The water outlet is connected to the upper part of the sulfur autotrophic zone. The bottom of the short-cut nitrification zone is equipped with an aeration pipe, and the top is equipped with an inclined first partition plate; the bottom of the anaerobic ammonium oxidation zone is equipped with an inclined second partition plate, and the second partition plate and the first partition plate enclose a gas-sludge-water separation chamber; the gas-sludge-water separation chamber exchanges gas and liquid with the adjacent short-cut nitrification zone and anaerobic ammonium oxidation zone through the first partition plate and the second partition plate, respectively; the bottom of the gas-sludge-water separation chamber is also connected to the short-cut nitrification zone through an aerobic sludge return port; The reactor is also provided with a vertically extending gas-liquid lifting channel and a mud-water separation channel. The lower end of the gas-liquid lifting channel is connected to the upper part of the short-cut nitrification zone, and the upper end is connected to the gas chamber. The mud-water separation channel is arranged around the outside of the gas-liquid lifting channel, with its lower end connected to the gas-mud-water separation chamber and its upper end connected to the gas chamber. A third partition plate is provided between the anaerobic ammonia oxidation zone and the sulfur autotrophic zone, which allows liquid exchange but retains particulate sludge; a clear liquid separation structure is provided in the sulfur autotrophic zone, and the outlet of the clear liquid separation structure is connected to the bottom of the anaerobic ammonia oxidation zone through a return circulation pipe.

[0008] The integrated autotrophic denitrification device for wastewater treatment provided by this invention may also have the following additional technical features: In some embodiments of the present invention, a plurality of first through holes are provided on the first partition plate, and the diameter of the first through holes gradually increases from bottom to top.

[0009] In some embodiments of the present invention, the tilt angle of the first partition plate is 15° to 30°, and the diameter of the first through hole is in the range of 1 mm to 3 mm.

[0010] In some embodiments of the present invention, the first partition plate is formed in a conical shape, and at least a portion of the periphery of the first partition plate surrounds the inner wall of the reactor to form the aerobic sludge return port.

[0011] In some embodiments of the present invention, the second partition plate is provided with a plurality of second through holes, the second through holes allowing liquid to pass through while trapping aerobic sludge; and / or The clear liquid separation structure is an independent chamber located within the sulfur autotrophic zone, with porous structures on its sidewalls or bottom.

[0012] In some embodiments of the present invention, the third partition plate is provided with a third through hole, the diameter of which is smaller than the particle size of the anaerobic ammonia oxidation granular sludge and the sulfur autotrophic denitrification granular sludge, so as to achieve selective interception and retention of functional bacterial granular sludge.

[0013] In some embodiments of the present invention, the effective volume ratio of the short-range nitrification zone, the anaerobic ammonia oxidation zone, and the sulfur autotrophic zone is 5:5:1.

[0014] In some embodiments of the present invention, the gas-liquid lifting channel is made of a first pipe body, the bottom of the first pipe body being connected to the first partition plate, and the mud-water separation channel is made of a second pipe body, the bottom of the second pipe body being connected to the second partition plate.

[0015] A second aspect of the present invention also provides an integrated autotrophic denitrification method for wastewater treatment using any of the above-described devices, comprising the following steps: Wastewater enters the short-cut nitrification zone through the inlet pipe, where it undergoes a short-cut nitrification reaction under low dissolved oxygen conditions, converting some ammonia nitrogen into nitrite nitrogen. The mud-water-gas mixture produced in the short-range nitrification zone rises along the surface of the first partition plate and enters the gas-liquid lifting channel, and is then transported to the gas chamber; the other part enters the gas-mud-water separation chamber through the first through hole of the first partition plate. The mixed liquid entering the gas-sludge-water separation chamber undergoes three-phase separation of gas, sludge, and water within the chamber: the separated gas enters the gas chamber through the sludge-water separation channel; the separated aerobic sludge returns to the lower part of the short-cut nitrification zone through the aerobic sludge return port; and the separated supernatant enters the anaerobic ammonium oxidation zone through the second through hole of the second partition plate. In the anaerobic ammonia oxidation zone, ammonia nitrogen and nitrite nitrogen in the supernatant undergo an anaerobic ammonia oxidation reaction under the action of anaerobic ammonia oxidizing bacteria to produce nitrogen gas and some nitrate nitrogen; The effluent from the anaerobic ammonia oxidation zone enters the sulfur autotrophic zone through the third partition plate. Under the action of sulfur autotrophic denitrifying bacteria, elemental sulfur is used as an electron donor to reduce nitrate nitrogen to nitrogen gas. The clear liquid separated by the clear liquid separation structure in the sulfur autotrophic zone is returned to the bottom of the anaerobic ammonia oxidation zone through the return circulation pipe under negative pressure, so as to realize internal circulation dilution and sludge washing. The treated water is discharged from the outlet at the top of the reactor, and the gas generated in each reaction zone is discharged from the gas outlet.

[0016] A third aspect of the present invention also provides a wastewater treatment system comprising the integrated autotrophic denitrification device for wastewater treatment described in any of the preceding claims. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1This is a schematic diagram of the integrated autotrophic denitrification device for wastewater treatment in an embodiment of the present invention; Figure 2 for Figure 1 Top view of the first section; Figure 3 The results of laboratory operation of the integrated autotrophic denitrification device for wastewater treatment in this embodiment of the invention are shown.

[0019] Explanation of reference numerals in the attached figures: 100-Integrated autotrophic denitrification unit for wastewater treatment; 1-Short-cut nitrification zone; 2-Anaerobic ammonia oxidation zone; 3-Sulfate autotrophic zone; 4-Inlet pipe; 5-Aeration pipe; 6-First partition plate; 7-Gas-liquid lifting channel; 8-Sludge-water separation channel; 9-Gas-sludge-water separation chamber; 10-Aerobic sludge return port; 11-Second partition plate; 12-Third partition plate; 13-Clear liquid separation structure; 14-Outlet; 15-Air outlet; 16-Air chamber; 17-First through hole. Detailed Implementation

[0020] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0021] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0022] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0023] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0024] Reference Figure 1-2As shown, the first aspect of the present invention provides an integrated autotrophic denitrification device 100 for wastewater treatment. The device includes a reactor, within which, from bottom to top, are arranged a short-cut nitrification zone 1, an anaerobic ammonia oxidation zone 2, a sulfur autotrophic zone 3, and a gas chamber 16. An inlet pipe 4 communicating with the short-cut nitrification zone 1 is located at the bottom of the reactor, and an air outlet 15 and a water outlet 14 are located at the top. The water outlet 14 communicates with the upper part of the sulfur autotrophic zone 3. An aeration pipe 5 is located at the bottom of the short-cut nitrification zone 1, and an inclined first partition plate 6 is located at the top. An inclined second partition plate 11 is located at the bottom of the anaerobic ammonia oxidation zone 2. The second partition plate 11 and the first partition plate 6 enclose a gas-sludge-water separation chamber 9. The gas-sludge-water separation chamber 9 is connected to the first partition plate 6 and the second partition plate 11. The reactor exchanges gas and liquid with the adjacent short-cut nitrification zone 1 and anaerobic ammonium oxidation zone 2. The bottom of the gas-sludge-water separation chamber 9 is also connected to the short-cut nitrification zone 1 through the aerobic sludge return port 10. The reactor is also equipped with a vertically extending gas-liquid lifting channel 7 and a sludge-water separation channel 8. The lower end of the gas-liquid lifting channel 7 is connected to the upper part of the short-cut nitrification zone 1, and the upper end is connected to the gas chamber 16. The sludge-water separation channel 8 is arranged around the outside of the gas-liquid lifting channel 7. Its lower end is connected to the gas-sludge-water separation chamber 9, and its upper end is connected to the gas chamber 16. A third partition plate 12 that allows liquid exchange but retains granular sludge is provided between the anaerobic ammonium oxidation zone 2 and the sulfur autotrophic zone 3. A clear liquid separation structure 13 is provided in the sulfur autotrophic zone 3. The outlet of the clear liquid separation structure 13 is connected to the bottom of the anaerobic ammonium oxidation zone 2 through a return circulation pipe.

[0025] In the above structure, the reactor is a vertical cylindrical structure, with the short-cut nitrification zone 1, anaerobic ammonia oxidation zone 2, sulfur autotrophic zone 3, and gas chamber 16 integrated vertically to form a unified structure. An inlet pipe 4, connected to the short-cut nitrification zone 1, is located at the bottom of the reactor to introduce wastewater to be treated. An outlet 15 and a water outlet 14 are located at the top of the reactor. The water outlet 14 is connected to the upper part of the sulfur autotrophic zone 3 for discharging treated clean water. The outlet 15 is connected to the gas chamber 16 for discharging gas outside the reactor. An aeration pipe 5 is also located at the bottom of the reactor to supply microbubbles to the short-cut nitrification zone 1, maintaining a low dissolved oxygen environment.

[0026] The short-cut nitrification zone 1, the anammox zone 2, and the sulfur autotrophic zone 3 are separated by a first partition plate 6, a second partition plate 11, and a third partition plate 12. The first partition plate 6, the second partition plate 11, and the third partition plate 12 are inclined and spaced apart between the short-cut nitrification zone 1 and the anammox zone 2, with the second partition plate 11 positioned above the first partition plate 6. A gas-sludge-water separation chamber 9 is formed between the first partition plate 6 and the second partition plate 11. The third partition plate 12 is located between the anammox zone 2 and the sulfur autotrophic zone 3. All three partition plates—first partition plate 6, second partition plate 11, and third partition plate 12—allow gas and liquid to pass through while retaining sludge.

[0027] The anaerobic ammonia oxidation zone 2 and the sulfur autotrophic zone 3 are also equipped with vertically extending gas-liquid lifting channels 7 and mud-water separation channels 8. The lower end of the gas-liquid lifting channel 7 is connected to the upper part of the short-cut nitrification zone 1, and the upper end is connected to the gas chamber 16. The mud-water separation channel 8 is arranged around the outside of the gas-liquid lifting channel 7, with its lower end connected to the gas-mud-water separation chamber 9 and its upper end connected to the gas chamber 16. The sulfur autotrophic zone 3 is equipped with a clear liquid separation structure 13, and the outlet of the clear liquid separation structure 13 is connected to the bottom of the anaerobic ammonia oxidation zone 2 through a reflux circulation pipe.

[0028] Thus, during the wastewater treatment process, wastewater enters the short-cut nitrification zone 1 through the inlet pipe 4, where it undergoes a short-cut nitrification reaction under low dissolved oxygen conditions, converting some ammonia nitrogen into nitrite nitrogen. A portion of the sludge-water-gas mixture produced in the short-cut nitrification zone 1 rises along the surface of the first partition plate 6 and enters the gas-liquid lifting channel 7, which then transports it to the gas chamber 16. The other portion enters the gas-sludge-water separation chamber 9 through the first through-hole 17 of the first partition plate 6. The mixture entering the gas-sludge-water separation chamber 9 undergoes three-phase separation of gas, sludge, and water within the chamber: the separated gas enters the gas chamber 16 through the sludge-water separation channel 8; the separated aerobic sludge returns to the short-cut nitrification zone 1 through the aerobic sludge return port 10; and the separated supernatant passes through the second partition plate 11. The second through-hole of the separator 1111 leads into the anaerobic ammonia oxidation zone 2. In the anaerobic ammonia oxidation zone 2, ammonia nitrogen and nitrite nitrogen in the supernatant undergo an anaerobic ammonia oxidation reaction under the action of anaerobic ammonia oxidizing bacteria to generate nitrogen gas and some nitrate nitrogen. The effluent from the anaerobic ammonia oxidation zone 2 enters the sulfur autotrophic zone 3 through the third separator 12. Under the action of sulfur autotrophic denitrifying bacteria, elemental sulfur is used as an electron donor to reduce nitrate nitrogen to nitrogen gas. The clear liquid separated by the clear liquid separation structure 13 in the sulfur autotrophic zone 3 is returned to the bottom of the anaerobic ammonia oxidation zone 2 through the return circulation pipe under negative pressure to achieve internal circulation dilution and sludge washing. The treated clear water is discharged from the outlet 14 at the top of the reactor, and the gas generated in each reaction zone is discharged from the gas outlet 15.

[0029] In some embodiments, the first partition plate 6 has a plurality of first through holes 17, and the diameter of the first through holes 17 gradually increases from bottom to top.

[0030] Specifically, the first partition plate 6 is made of stainless steel and has multiple first through holes 17. The diameter of the first through holes 17 gradually increases from bottom to top. This allows the bubbles generated by aeration in the short-range nitrification zone 1 to move upward along the lower surface of the first partition plate 6 and gradually increase in size during the ascent. This facilitates the concentrated flow of bubbles to the gas-liquid lifting channel 7 and reduces the escape of small bubbles into the gas-slurry-water separation chamber 9.

[0031] In some embodiments, the tilt angle of the first partition plate 6 is 15° to 30°, and the diameter of the first through hole 17 ranges from 1 mm to 3 mm.

[0032] For example, the tilt angle of the first partition plate 6 is 15°, 18°, 20°, 22°, 25°, 28°, or 30°. For example, the diameter of the first through hole 17 is 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, or 3 mm. The specific diameter can be selected as needed.

[0033] In some embodiments, the first partition plate 6 is formed in a conical shape, and at least part of the periphery of the first partition plate 6 surrounds the inner wall of the reactor to form an aerobic sludge return port 10.

[0034] Because the first partition plate 6 is cone-shaped, the gas in the short-cut nitrification zone 1 can be concentrated towards the center. At the same time, because the aerobic sludge return port 10 is formed on the outer periphery of the first partition plate 6, the sludge in the gas-sludge-water separation chamber 9 can be naturally guided to the short-cut nitrification zone 1.

[0035] In some embodiments, the second partition plate 11 has a plurality of second through holes, which allow liquid to pass through while trapping aerobic sludge.

[0036] Specifically, the gas-sludge-water separation chamber 9 can accept sludge and water from the sludge-water separation channel 8, and can also accept a mixture of air bubbles and sludge and water entering from the first partition plate 6. The gas-sludge-water mixture is further separated in the gas-sludge-water separation chamber 9. The gas flows along the second partition plate 11 to the sludge-water separation channel 8, and the sludge flows back to the short-cut nitrification zone 1 through the aerobic sludge return port 10 and the first through hole 17 of the first partition plate 6. The supernatant flows to the anaerobic ammonia oxidation zone 2 through the second through hole of the second partition plate 11.

[0037] In some embodiments, the clear liquid separation structure 13 is an independent chamber located within the sulfur autotrophic zone 3, and its sidewalls or bottom have porous structures.

[0038] In some embodiments, the third partition plate 12 is provided with a third through hole, the diameter of which is smaller than the particle size of the anaerobic ammonia oxidation granular sludge and the sulfur autotrophic denitrification granular sludge, so as to achieve selective interception and retention of functional bacterial granular sludge.

[0039] In some embodiments, the effective volume ratio of the short-range nitrification zone 1, the anaerobic ammonia oxidation zone 2, and the sulfur autotrophic zone 3 is 5:5:1.

[0040] In some embodiments, the gas-liquid lifting channel 7 is made of a first pipe body, the bottom of which is connected to the first partition plate 6, and the mud-water separation channel 8 is made of a second pipe body, the bottom of which is connected to the second partition plate 11.

[0041] Specifically, the outer periphery of the second partition plate 11 is fixedly connected to the inner wall of the reactor, thereby fixing the second partition plate 11 and the second tube connected thereto within the reactor. Furthermore, a portion of the inner periphery of the second partition plate 11 extends to and is fixedly connected to the outer wall of the first tube, thereby fixing the first tube and the first partition plate 6 connected to the first tube within the reactor. It should be noted that the connection structure between the second partition plate 11 and the first tube can be radially arranged to avoid affecting the communication between the sludge-water separation channel 8 and the gas-sludge-water separation chamber 9.

[0042] The above settings enable the configuration of the first partition plate 6, the second partition plate 11, the mud-water separation channel 8, and the gas-liquid lifting channel 7.

[0043] The integrated autotrophic denitrification device 100 for wastewater treatment provided in this embodiment of the invention has the following beneficial effects: By integrating the short-cut nitrification zone 1, anaerobic ammonium oxidation zone 2, and sulfur autotrophic zone 3 into a single reactor and arranging them vertically from bottom to top, the project significantly reduces civil engineering costs and land area requirements, facilitating land conservation in new projects and upgrading of existing facilities. The functional zones are physically separated and their flow channels are designed to ensure coordinated operation, avoiding the complex pipelines and control difficulties associated with multiple reactors connected in series. By using the inclined first partition plate 6 and the gradient pore size design, aeration bubbles flow directionally along the inclined plate. Most of the gas directly enters the gas chamber 16 through the gas-liquid lifting channel 7, while only a small portion enters the gas-sludge-water separation chamber 9. This effectively reduces the adverse effects of dissolved oxygen on the upper anaerobic zone and the sulfur autotrophic zone 33. The gas-sludge-water separation chamber 9 achieves natural separation of the three phases of gas, sludge, and water. The sludge is automatically returned to the short-cut nitrification zone 1 without the need for external power or a return pump, significantly reducing energy consumption. The second partition plate 11 retains aerobic sludge through pore size control, preventing it from entering the anaerobic zone and interfering with anaerobic ammonia oxidation bacteria. The third partition plate 12 retains anaerobic ammonia oxidation granular sludge and sulfur autotrophic denitrification granular sludge through pore size control, achieving selective retention and enrichment of functional bacteria, preventing the loss of dominant bacteria, and significantly improving the system's operational stability. The localized negative pressure created in the sulfur autotrophic zone 3 (sulfur autotrophic zone 33) by the aeration in the short-cut nitrification zone 1 and the gas generated in the anaerobic ammonium oxidation zone 2 drives the clarified liquid to automatically return to the bottom of the anaerobic ammonium oxidation zone 2 via the return circulation pipe, eliminating the need for an external circulation pump. This internal circulation can dilute the substrate concentration, reduce high-concentration inhibition, flush granular sludge to prevent floating, and simultaneously promote the in-situ neutralization of the acid produced by sulfur autotrophic denitrification and the alkali produced by anaerobic ammonium oxidation, maintaining the pH stability of the reactor. By synergistically coupling short-cut nitrification, anaerobic ammonium oxidation, and sulfur autotrophic denitrification, the autotrophic nitrogen removal advantages of anaerobic ammonium oxidation and sulfur autotrophic denitrification are fully utilized, eliminating the need for external organic carbon sources. Short-cut nitrification saves approximately 25% of aeration volume compared to traditional complete nitrification, significantly reducing overall energy consumption. It is particularly suitable for treating high-ammonia-nitrogen, low-carbon industrial wastewater such as photovoltaic wastewater, electronics industry wastewater, and landfill leachate with a carbon-to-nitrogen ratio below 0.1 and an ammonia-nitrogen concentration of 1000-1500 mg / L. It can also be extended to the denitrification upgrade of small and medium-sized municipal wastewater treatment plants, demonstrating broad application prospects.

[0044] This invention also provides an integrated autotrophic denitrification method for wastewater treatment using the above-mentioned device, the method comprising the following steps: Step 1: Wastewater enters the short-cut nitrification zone 1 through inlet pipe 4. This embodiment uses photovoltaic wastewater as an example. The wastewater quality is: ammonia nitrogen concentration 1000–1500 mg / L, C / N < 0.1. Microporous aeration is performed through aeration pipe 5 to control the dissolved oxygen concentration at 0.3–0.5 mg / L. Utilizing the inhibitory effect of free ammonia, approximately 50% of the ammonia nitrogen in the influent is converted to nitrite nitrogen, resulting in an effluent nitrite nitrogen concentration of approximately 350–500 mg / L. Simultaneously, the small amount of residual organic carbon source in the influent is utilized by denitrifying bacteria under low dissolved oxygen conditions, achieving partial denitrification and reducing the adverse effects of organic carbon on the subsequent anaerobic ammonia oxidation process.

[0045] Step 2: The mud-water-gas mixture generated in the short-range nitrification zone 1 forms two flow directions under the impetus of aeration: the main flow mixture rises along the surface of the first partition plate 6. Since the first partition plate 6 is inclined at about 20° and the diameter of the first through hole 17 gradually increases from bottom to top, most of the bubbles move upward along the lower surface of the first partition plate 6, carrying the mud-water mixture into the gas-liquid lifting channel 7. Through the gas-liquid lifting channel 7, the gas is directly transported to the top gas chamber 16, while the mud-water mixture returns to the gas-mud-water separation chamber 9 through the mud-water separation channel 8; the branch flow mixture enters the gas-mud-water separation chamber 9 through the first through hole 17 of the first partition plate 6.

[0046] Step 3: The mixed liquid entering the gas-sludge-water separation chamber 9 undergoes three-phase separation of gas, sludge, and water within the chamber: the separated microbubbles rise under buoyancy and enter the top gas chamber 16 through the sludge-water separation channel 8; the separated aerobic sludge flocs settle under gravity and return to the short-cut nitrification zone 1 along the aerobic sludge return port 10, achieving effective interception and return of aerobic sludge; the separated supernatant contains ammonia nitrogen and nitrite nitrogen and enters the anaerobic ammonia oxidation zone 2 through the second through-hole of the second partition plate 11. The second through-hole effectively intercepts aerobic sludge, preventing it from entering the anaerobic zone and interfering with the anaerobic ammonia oxidation bacteria.

[0047] Step four: In anaerobic ammonia oxidation zone 2, ammonia nitrogen and nitrite nitrogen in the supernatant undergo an anaerobic ammonia oxidation reaction under the action of anaerobic ammonia oxidizing bacteria, generating nitrogen gas and some nitrate nitrogen. In this embodiment, anaerobic ammonia oxidation zone 2 maintains a strictly anaerobic environment, with NH4+... + -N and NO2 - -N is converted into N2 gas through anaerobic ammonium oxidation, while a portion of NO3 is generated. - -N, effluent ammonia nitrogen concentration 32±20 mg / L, nitrite nitrogen concentration 13±28 mg / L, nitrate nitrogen concentration 56±10 mg / L.

[0048] Step 5: The effluent from anaerobic ammonia oxidation zone 2 enters sulfur autotrophic zone 3 through the third through-hole of the third partition plate 12. The third through-hole has a diameter of 1.0 mm, effectively trapping anaerobic ammonia oxidation granular sludge and preventing the loss of dominant bacteria. Sulfur autotrophic zone 3 is filled with elemental sulfur particles. Under the action of sulfur autotrophic denitrifying bacteria, elemental sulfur acts as an electron donor, reducing nitrate nitrogen to nitrogen gas. In this embodiment, the effluent contains NH4+. + -N, NO2 - -N concentration dropped below 10 mg / L, while NO3 - -N remained stable at 20±14 mg / L, and the final TN concentration in the effluent decreased to 37±16 mg / L, demonstrating a very good denitrification effect.

[0049] Step six: The mixed liquor in the sulfur autotrophic zone 3 enters an independent chamber through the porous sidewall of the clear liquid separation structure 13 for sludge-water separation. The clear liquid clarifies upwards within the chamber. Due to the upward flow of bubbles generated in the short-cut nitrification zone 1 and the anaerobic ammonia oxidation zone 2 to the sulfur autotrophic zone 3, a localized slight negative pressure is formed near the outlet of the clear liquid separation structure 13. This negative pressure drives the clarified clear liquid to flow back to the bottom of the anaerobic ammonia oxidation zone 2 through the return circulation pipe, achieving internal circulation. The circulation flow rate is controlled at 50% of the influent flow rate, which effectively dilutes the substrate concentration at the bottom of the anaerobic ammonia oxidation zone 2, reducing the inhibitory effect of high concentrations of ammonia nitrogen and nitrite nitrogen on anaerobic ammonia oxidizing bacteria. Simultaneously, it washes the surface of the granular sludge, removing attached bubbles and preventing the granular sludge from floating and being lost.

[0050] Step 7: The treated water is discharged from the outlet 14 at the top of the reactor, and the gases generated in each reaction zone (including the residual air from short-cut nitrification, nitrogen generated from anaerobic ammonia oxidation, and nitrogen generated from sulfur autotrophic denitrification) are discharged from the outlet 15.

[0051] like Figure 3 As shown, after 100 days of laboratory monitoring, the integrated autotrophic denitrification device for wastewater treatment provided by this invention perfectly validated its design concept: as wastewater flows from bottom to top through each functional zone, different forms of nitrogen pollutants are treated separately and reduced step by step. From ammonia nitrogen in the influent, to nitrite nitrogen after short-cut nitrification, and then to nitrate nitrogen after anaerobic ammonia oxidation, all nitrogen is finally converted into nitrogen gas in the sulfur autotrophic zone, achieving a stepwise reduction of pollutants to zero. This fully demonstrates that the device of this invention has excellent, stable, and efficient deep treatment capabilities for wastewater with high ammonia nitrogen and low carbon-to-nitrogen ratio.

[0052] A second aspect of the present invention also provides a wastewater treatment system comprising an integrated autotrophic denitrification device 100 for wastewater treatment as described above. The integrated autotrophic denitrification device 100 for wastewater treatment is described in the above embodiments. Since the wastewater treatment system includes the integrated autotrophic denitrification device 100 for wastewater treatment in all the above embodiments, it also possesses at least the beneficial effects of the above embodiments, which will not be elaborated upon here.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An integrated autotrophic denitrification device for wastewater treatment, characterized in that, The reactor includes a short-cut nitrification zone, an anaerobic ammonia oxidation zone, a sulfur autotrophic zone, and a gas chamber arranged sequentially from bottom to top. The reactor is provided with an inlet pipe at the bottom that is connected to the short-cut nitrification zone, and an outlet and a water outlet at the top. The water outlet is connected to the upper part of the sulfur autotrophic zone. The bottom of the short-cut nitrification zone is provided with an aeration pipe, and the top is provided with an inclined first partition plate; the bottom of the anaerobic ammonium oxidation zone is provided with an inclined second partition plate, and the second partition plate and the first partition plate enclose a gas-sludge-water separation chamber. The gas-sludge-water separation chamber exchanges gas and liquid with the adjacent short-cut nitrification zone and anaerobic ammonia oxidation zone through the first partition plate and the second partition plate, respectively. The bottom of the gas-sludge-water separation chamber is also connected to the short-cut nitrification zone through the aerobic sludge return port. The reactor is also provided with a vertically extending gas-liquid lifting channel and a mud-water separation channel. The lower end of the gas-liquid lifting channel is connected to the upper part of the short-cut nitrification zone, and the upper end is connected to the gas chamber. The mud-water separation channel is arranged around the outside of the gas-liquid lifting channel, with its lower end connected to the gas-mud-water separation chamber and its upper end connected to the gas chamber. A third partition plate is provided between the anaerobic ammonia oxidation zone and the sulfur autotrophic zone, which allows liquid exchange but retains particulate sludge; a clear liquid separation structure is provided in the sulfur autotrophic zone, and the outlet of the clear liquid separation structure is connected to the bottom of the anaerobic ammonia oxidation zone through a return circulation pipe.

2. The apparatus according to claim 1, characterized in that, The first partition plate has multiple first through holes, and the diameter of the first through holes gradually increases from bottom to top.

3. The apparatus according to claim 2, characterized in that, The tilt angle of the first partition plate is 15° to 30°, and the diameter of the first through hole is 1mm to 3mm.

4. The apparatus according to claim 2 or 3, characterized in that, The first partition plate is formed in a cone shape, and at least a portion of the periphery of the first partition plate surrounds the inner wall of the reactor to form the aerobic sludge return port.

5. The apparatus according to claim 1, characterized in that, The second partition plate has multiple second through holes, which allow liquid to pass through while trapping aerobic sludge; and / or The clear liquid separation structure is an independent chamber located within the sulfur autotrophic zone, with porous structures on its sidewalls or bottom.

6. The apparatus according to claim 5, characterized in that, The third partition plate is provided with a third through hole, the diameter of which is smaller than the particle size of the anaerobic ammonia oxidation granular sludge and the sulfur autotrophic denitrification granular sludge, so as to achieve selective interception and retention of functional bacterial granular sludge.

7. The apparatus according to claim 5, characterized in that, The effective volume ratio of the short-range nitrification zone, the anaerobic ammonia oxidation zone, and the sulfur autotrophic zone is 5:5:

1.

8. The apparatus according to claim 1, characterized in that, The gas-liquid lifting channel is made of a first pipe body, the bottom of which is connected to the first partition plate. The mud-water separation channel is made of a second pipe body, the bottom of which is connected to the second partition plate.

9. A wastewater treatment integrated autotrophic denitrification method using the apparatus described in any one of claims 1 to 8, characterized in that, Includes the following steps: Wastewater enters the short-cut nitrification zone through the inlet pipe, where it undergoes a short-cut nitrification reaction under low dissolved oxygen conditions, converting some ammonia nitrogen into nitrite nitrogen. The mud-water-gas mixture produced in the short-range nitrification zone rises along the surface of the first partition plate and enters the gas-liquid lifting channel, and is then transported to the gas chamber; the other part enters the gas-mud-water separation chamber through the first through hole of the first partition plate. The mixed liquid entering the gas-sludge-water separation chamber undergoes three-phase separation of gas, sludge, and water within the chamber: the separated gas enters the gas chamber through the sludge-water separation channel; the separated aerobic sludge returns to the lower part of the short-cut nitrification zone through the aerobic sludge return port; and the separated supernatant enters the anaerobic ammonium oxidation zone through the second through hole of the second partition plate. In the anaerobic ammonia oxidation zone, ammonia nitrogen and nitrite nitrogen in the supernatant undergo an anaerobic ammonia oxidation reaction under the action of anaerobic ammonia oxidizing bacteria to produce nitrogen gas and some nitrate nitrogen; The effluent from the anaerobic ammonia oxidation zone enters the sulfur autotrophic zone through the third partition plate. Under the action of sulfur autotrophic denitrifying bacteria, elemental sulfur is used as an electron donor to reduce nitrate nitrogen to nitrogen gas. The clear liquid separated by the clear liquid separation structure in the sulfur autotrophic zone is returned to the bottom of the anaerobic ammonia oxidation zone through the return circulation pipe under negative pressure, so as to realize internal circulation dilution and sludge washing. The treated water is discharged from the outlet at the top of the reactor, and the gas generated in each reaction zone is discharged from the gas outlet.

10. A wastewater treatment system, characterized in that, It includes an integrated autotrophic denitrification device for wastewater treatment as described in any one of claims 1 to 8.

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