Multi-point dosing hydrogen substrate autotrophic denitrification membrane bioreactor

Abstract

This application provides a multi-point hydrogen-addition substrate autotrophic denitrification membrane bioreactor, comprising: a membrane shell and a columnar body; a first end cap on one side of the body, an inlet in the middle, and a first end cap air inlet connected to a cavity inside the first end cap; a second end cap with a second end cap air inlet connected to a cavity inside the second end cap, the first and second end cap air inlets being connected to a hydrogen source via pipelines; a hollow central tube within the body, one side of which is fixed to the first end cap and connected to the inlet, and the other side of which is fixed to the second end cap, with perforated areas on the sidewall; a membrane fabric wound around the central tube; and multiple membrane fibers connected to cavities of the end caps on both sides. Through multi-point gas intake via the end cap air inlets on both sides, hydrogen is evenly distributed on the outer surface of the membrane fibers, hydrogen autotrophic bacteria are evenly attached to the membrane fibers, and the denitrification efficiency is stable.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and in particular to a multi-point hydrogen-addition matrix autotrophic denitrification membrane bioreactor. Background Technology

[0002] In recent years, increasingly stringent emission standards have been set for deep nitrogen removal and upgrading projects, especially for total nitrogen and ammonia nitrogen. Traditional biological nitrogen removal processes mainly rely on heterotrophic denitrification, which requires the addition of organic carbon sources (such as methanol and acetic acid), resulting in high operating costs and a high risk of secondary pollution. In recent years, autotrophic denitrification technology has attracted attention due to its high efficiency, economy, and environmental friendliness. Hydrogen-based autotrophic denitrification technology uses hydrogen as an electron donor to convert nitrate nitrogen into nitrogen gas, offering advantages such as no need for organic carbon sources and low sludge production. However, existing hydrogen-based denitrification reactors suffer from problems such as low hydrogen utilization, unstable nitrogen removal efficiency, and severe membrane fouling.

[0003] Therefore, there is an urgent need for a high-efficiency, stable, and low-cost hydrogen-based autotrophic denitrification membrane bioreactor. Utility Model Content

[0004] In view of this, the purpose of this disclosure is to propose a multi-point hydrogen-addition substrate autotrophic denitrification membrane bioreactor with high hydrogen utilization and stable denitrification efficiency.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] A multi-point hydrogen-addition substrate autotrophic denitrification membrane bioreactor, comprising:

[0007] A membrane shell and a columnar body, wherein the membrane shell is fitted onto the body;

[0008] The main body has a first end cap on one side, a water inlet in the middle of the first end cap, and a first end cap air inlet, which is connected to a cavity inside the first end cap.

[0009] A second end cap is provided on the side of the main body away from the first end cap. The second end cap has a second end cap air inlet. The second end cap air inlet is connected to the cavity inside the second end cap. The first end cap air inlet and the second end cap air inlet are respectively connected to a hydrogen source via pipelines.

[0010] The body has a hollow central tube, one side of which is fixed to the first end cap and communicates with the water inlet, and the other side is fixed to the second end cap. An opening area is provided on the side wall of the central tube.

[0011] Multiple membrane filaments are arranged circumferentially along the central tube, with one end of each filament fixed to the first end cap and communicating with the cavity of the first end cap, and the other end fixed to the second end cap and communicating with the cavity of the second end cap; and a spacer is wound around the central tube to separate the membrane filaments.

[0012] Preferably, the second end cap is provided with a cleaning air inlet, which is connected to the central tube.

[0013] Preferably, the cleaning air inlet is located in the middle of the second end cap.

[0014] Preferably, the scrubbing air inlet is connected to an air source via a pipeline.

[0015] Preferably, the outer diameter of the membrane filament is 250-350 μm and the inner diameter is 150-200 μm.

[0016] Preferably, the first end cap is provided with a plurality of air inlets, which are connected to the membrane filament.

[0017] Preferably, the plurality of air inlets are arranged in a circular shape.

[0018] Preferably, the first end cap has a hollow protrusion disposed along its axial direction, the protrusion fixing the

[0019] The central tube, with the protrusion connected to the water inlet.

[0020] Preferably, the protrusion, together with the side wall and part of the bottom of the first end cap, forms a cavity within the first end cap.

[0021] Preferably, the second end cap has a hollow protrusion arranged along its axial direction, the protrusion fixing the central tube, and the protrusion communicating with the cleaning air inlet.

[0022] Compared with existing technologies, the multi-point hydrogen-addition matrix autotrophic denitrification membrane bioreactor disclosed in this disclosure introduces hydrogen gas through the air inlets of the end caps (first / second end caps) on both sides, ensuring uniform distribution of hydrogen on the outer surface of the membrane fibers. This results in 100% hydrogen utilization efficiency, allowing hydrogen-autotrophic bacteria to uniformly attach to the membrane fibers and maintain stable nitrogen removal efficiency. Compared with traditional denitrification processes, no external organic carbon source is required, significantly reducing reagent costs and minimizing secondary pollution. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in this disclosure or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the internal structure of the multi-point hydrogen-doping matrix autotrophic denitrification membrane bioreactor according to an embodiment of this application.

[0025] Figure 2 This is a schematic diagram of the membrane fabric structure according to an embodiment of this application.

[0026] Figure 3 This is a schematic diagram of the membrane bioreactor according to an embodiment of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0028] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this disclosure should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in the embodiments of this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0029] As revealed in the background section, traditional biological nitrogen removal processes mainly rely on heterotrophic denitrification, requiring the addition of organic carbon sources (such as methanol and acetic acid), resulting in high operating costs and a high risk of secondary pollution. Hydrogen-based autotrophic denitrification technology utilizes hydrogen as an electron donor to convert nitrate nitrogen into nitrogen gas, offering advantages such as no need for organic carbon sources and low sludge production. However, existing hydrogen-based denitrification reactors suffer from problems such as low hydrogen utilization, unstable nitrogen removal efficiency, and severe membrane fouling.

[0030] To address this issue, the applicant proposes a multi-point hydrogen-based autotrophic denitrification membrane bioreactor. This aims to solve the problems of low hydrogen utilization, unstable denitrification efficiency, and severe membrane fouling found in existing hydrogen-based denitrification reactors. During operation, this multi-point hydrogen-based autotrophic denitrification membrane bioreactor introduces hydrogen through the air inlets of its two end caps (first / second end caps), ensuring uniform distribution of hydrogen on the outer surface of the membrane fibers. This results in 100% hydrogen utilization efficiency, allowing hydrogen autotrophic bacteria to adhere evenly to the membrane fibers and maintain stable denitrification efficiency. Air enters the central tube through the air scrubbing inlet of the second end cap, contacting and disturbing the biofilm on the outer surface of the membrane fibers via the open area of ​​the central tube, causing it to detach and mitigating membrane fouling, thus extending the membrane cleaning cycle. A periodic synergistic reaction process occurs between air and the oxidant introduced through the water inlet of the first end cap, effectively removing the strongly adhering biofilm from the membrane fibers through physical and chemical actions. The hydrogen autotrophic denitrifying bacteria on the membrane fibers continuously renew and multiply, ensuring a sustained and efficient denitrification effect.

[0031] Next, we will combine the appendix Figures 1-3 This application describes the multi-point hydrogen-addition substrate autotrophic denitrification membrane bioreactor (hereinafter referred to as membrane bioreactor). It enables a highly efficient autotrophic denitrification process through multi-point gas addition.

[0032] The membrane bioreactor includes a membrane shell 9 and a columnar body located inside the membrane shell 9.

[0033] The main body has a first end cap 3 on one side, a water inlet 1 in the middle of the first end cap 3, and a first end cap air inlet 2, which is connected to the cavity inside the first end cap 3.

[0034] The other side of the main body has a second end cap 10, which has a second end cap air inlet 11. The second end cap air inlet 11 is connected to a cavity inside the second end cap 10. The first end cap air inlet 2 and the second end cap air inlet 11 are respectively connected to a gas source (hydrogen source) via pipelines.

[0035] The first end cap 3 has a hollow protrusion 3b arranged along its axial direction. The protrusion 3b fixes the central tube 4 and connects to the water inlet 1. The protrusion, together with the side wall and part of the bottom of the first end cap, forms a cavity 3a inside the first end cap.

[0036] The second end cap 10 has a hollow protrusion 10b arranged along its axial direction. The protrusion 10b fixes the central tube 4 and connects to the cleaning air inlet 12.

[0037] The main body has a hollow central tube 4. One side of the central tube 4 is fixed to a first end cap 3 and communicates with a water inlet 1, while the other side is fixed to a second end cap 10 and communicates with a scrubbing air inlet 12, which is located in the middle of the second end cap 10. An opening area 5 is provided on the side wall of the central tube 4, and multiple layers of film are wound around the central tube 4. The scrubbing air inlet 12 is connected to an air source (such as air) via a pipeline.

[0038] The membrane includes membrane fibers 6 and spacers 8. The membrane fibers 6 are made of a high-hydrogen-flux, high-strength, surface-modified material with an outer diameter of 250-350 μm and an inner diameter of 150-200 μm; for example, the membrane fibers 6 may have an outer diameter of 300 μm and an inner diameter of 180 μm. In this embodiment, the membrane fibers 6 are hollow tubular, with one end fixed and connected to the cavity 3a of the first end cap 3, and the other end fixed and connected to the cavity 10a of the second end cap 10. The spacers 8 are wound around the central tube to space the membrane fibers 6. The membrane includes membrane fibers 6, a membrane fabric 7, and spacers 8, which support the strength of the membrane fibers 6. The membrane fabric 7 includes insulating fibers that are approximately 90° to the membrane fibers; this weaving structure is disclosed in the prior art (e.g., CN111939764A).

[0039] Preferably, the first end cap 3 and the second end cap 10 are provided with multiple air inlets, which are connected to the membrane fibers 6. These multiple air inlets are arranged in a circular shape, with each circular air inlet connecting to a corresponding membrane fiber 6, effectively wrapping around the central tube 4 (multiple wraps / layers can be formed depending on the application). The membrane fiber 6 is supported by the membrane cloth 7 and the spacer 8. Hydrogen gas enters through multiple points via the air inlets on the upper and lower end caps, resulting in a uniform distribution of hydrogen gas on the outer surface of the membrane fibers. Hydrogen-autotrophic bacteria then uniformly attach to the membrane fibers, ensuring stable denitrification efficiency.

[0040] Preferably, the first end cap 3 has a fixing part 3c, on which an air inlet is provided. The fixing part 3c fixes the membrane filament, which is connected to the air inlet and then to the cavity 3a inside the first end cap 3.

[0041] Preferably, the second end cap 10 has a fixing part 10c, on which a plurality of air inlets are provided. The fixing part 10c fixes the membrane filament, which is connected to the air inlets and then to the cavity 10a inside the second end cap 10.

[0042] Air enters the central tube through the lower air scrubbing inlet, and after passing through the opening area of ​​the central tube, it comes into contact with and disturbs the biofilm on the outer surface of the membrane fibers, causing it to detach, thus slowing down the membrane fouling trend and extending the membrane cleaning cycle. The air and the oxidant entering from the upper water inlet periodically undergo a synergistic reaction process, effectively removing the strongly adhesive biofilm on the membrane fibers through physical and chemical actions. The hydrogen autotrophic denitrifying bacteria on the membrane fibers are constantly renewed and multiplied, and the continuous and efficient hydrogen autotrophic denitrifying bacteria ensure the nitrogen removal effect.

[0043] The membrane fabric 7 is woven with the spacing between adjacent membrane fibers 6 being 0.5-2 times the outer diameter of the membrane fibers 6. A mesh with a thickness of 1-2 times the outer diameter of the membrane fibers 6 surrounds the central tube on the outer side of the membrane fabric 7. This membrane bioreactor uses a multi-point hydrogen inlet method to evenly distribute hydrogen gas on the outer surface of the membrane fibers. Furthermore, hydrogen autotrophic bacteria become the dominant bacterial group and adhere evenly to the membrane fibers, resulting in a stable nitrogen removal efficiency maintained above 85%. During cleaning, air is introduced through the scrubbing inlet 12. Air scrubbing effectively slows down membrane fouling without altering the properties of the membrane fibers, extending the membrane cleaning cycle by 2 times. The combined use of air scrubbing and chemical cleaning effectively removes strongly adhesive biofilm from the membrane fibers through physical and chemical action. More than 80% of the biofilm on the membrane fibers is removed, and hydrogen autotrophic denitrifying bacteria remain the dominant bacterial group in the remaining biofilm. Compared with traditional denitrification processes, no external organic carbon source is required, significantly reducing reagent costs and minimizing secondary pollution.

[0044] In one embodiment, the air scrubbing inlet 12 may be provided on the outer surface of the membrane fiber 6, so that the compressed gas introduced through it blows onto the outer surface of the membrane fiber 6.

[0045] The membrane bioreactor is placed inside the membrane tank during operation. The process flow includes: activated sludge acclimation, membrane attachment and start-up, reactor operation, and membrane cleaning.

[0046] Activated sludge acclimation: Wash the inoculated sludge twice, add water to the sludge mixture in an artificial ratio of C:N:P = 100:5:1 to make the sludge concentration 3-5 g / L, and add the acclimated sludge into the membrane tank to wait for the membrane to start the process.

[0047] Water inlet method: Water enters the central tube 4 from the inlet 1 and diffuses to the outer surface of the membrane fiber 6 through the opening area 5 of the central tube;

[0048] In the hydrogen inlet method, hydrogen enters the hollow membrane fiber 6 simultaneously from the first end cap inlet 2 and the second end cap inlet 11, and diffuses from the inner cavity of the membrane fiber 6 to the outer surface of the membrane fiber 6.

[0049] Biofilm formation start-up: The membrane bioreactor is placed in the membrane tank, and artificially prepared water with nitrate nitrogen is introduced. Hydrogen gas is introduced, and glucose, ammonium chloride, and potassium dihydrogen phosphate are added in a ratio of C:N:P = 100:5:1 to increase the COD of the membrane tank solution to 100-200 mg / L. The artificially prepared water with nitrate nitrogen, sludge, and hydrogen gas fully contact and react on the outer surface of membrane fiber 6 until a visible microbial film appears on membrane fiber 6. The nitrate nitrogen removal rate reaches more than 80%, the pH of the effluent rises, and the microbial biofilm formation is successful.

[0050] Membrane cleaning process: An air scrubbing process is performed once a week. The system is equipped with a high-efficiency aeration device that provides an appropriate amount of air, which enters the central tube 4 through the air scrubbing inlet 12 and diffuses through the central tube opening area 5 to the outer surface of the membrane fibers 6 for air scrubbing. The air volume is (0.5-0.6 Nm³).3 / (m 2 ·h))* Membrane area (m 2 The calculation showed that the time was 2 minutes. An oxidant-assisted gas scrubbing process was performed once a month, with 500 mg / L sodium hypochlorite (effective chlorine concentration of 10%) introduced into the membrane bioreactor via the influent method, and the scrubbing time was 30 minutes.

[0051] It should be noted that the above description describes some embodiments of this disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0052] This disclosure is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A multi-point hydrogen-addition substrate autotrophic denitrification membrane bioreactor, characterized in that, include: A membrane shell and a columnar body, wherein the membrane shell is fitted onto the body; The main body has a first end cap on one side, a water inlet in the middle of the first end cap, and a first end cap air inlet, which is connected to a cavity inside the first end cap. A second end cap is provided on the side of the main body away from the first end cap. The second end cap has a second end cap air inlet. The second end cap air inlet is connected to the cavity inside the second end cap. The first end cap air inlet and the second end cap air inlet are respectively connected to a hydrogen source via pipelines. The body has a hollow central tube, one side of which is fixed to the first end cap and communicates with the water inlet, and the other side is fixed to the second end cap. An opening area is provided on the side wall of the central tube. Multiple membrane filaments are arranged circumferentially along the central tube, with one end of each filament fixed to the first end cap and communicating with the cavity of the first end cap, and the other end fixed to the second end cap and communicating with the cavity of the second end cap; and a spacer is wound around the central tube to separate the membrane filaments.

2. The membrane bioreactor as described in claim 1, characterized in that, The second end cap is provided with a cleaning air inlet, which is connected to the central tube.

3. The membrane bioreactor as described in claim 2, characterized in that, The cleaning air inlet is located in the middle of the second end cap.

4. The membrane bioreactor as described in claim 3, characterized in that, The scrubbing air inlet is connected to an air source via a pipeline.

5. The membrane bioreactor as described in claim 1, characterized in that, The outer diameter of the membrane filament is 250-350 μm, and the inner diameter is 150-200 μm.

6. The membrane bioreactor as described in claim 1, characterized in that, The first end cap is provided with a plurality of air inlets, which are connected to the membrane filaments.

7. The membrane bioreactor as described in claim 6, characterized in that, The multiple air inlets are arranged in a circular shape.

8. The membrane bioreactor as described in claim 1, characterized in that, The first end cap has a hollow protrusion arranged along its axial direction, and the protrusion fixes the... The central tube, with the protrusion connected to the water inlet.

9. The membrane bioreactor as described in claim 8, characterized in that, The protrusion, together with the side wall and part of the bottom of the first end cap, forms a cavity within the first end cap.

10. The membrane bioreactor as described in claim 8, characterized in that, The second end cap has a hollow protrusion arranged along its axial direction, the protrusion fixing the The central tube, the protrusion of which is connected to the scrubbing air inlet.

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