A wastewater treatment device employing dark-light fermentation for biohydrogen production.

Abstract

This application relates to the field of bioenergy technology, specifically to a wastewater treatment device for dark-photocatalytic fermentation biohydrogen production. This device combines dark fermentation biohydrogen production with anaerobic ammonia oxidation to remove some organic matter and nitrogen oxides from wastewater, solving the problem of high concentrations of ammonia nitrogen in wastewater inhibiting hydrogen production efficiency. Photocatalytic fermentation further utilizes the dark fermentation products to produce hydrogen and converts sulfides into sulfates, thereby degrading the impact of organic acids and sulfides in the wastewater on subsequent water treatment technologies, reducing biotoxicity, and improving energy conversion efficiency. A nitrification reactor is combined with dark fermentation hydrogen production, and anaerobic ammonia oxidation is carried out in a cyclical manner to improve nitrogen removal efficiency, realizing an integrated device for organic wastewater hydrogen production and wastewater treatment.

Description

Technical Field

[0001] This application relates to the field of bioenergy technology, specifically to a wastewater treatment device for dark-light fermentation biohydrogen production. Background Technology

[0002] With societal development, energy consumption is gradually increasing, while fossil fuel reserves are limited, leading to ongoing disputes among countries over control and ownership of energy-producing regions. Developing renewable energy sources is an effective way to address fossil fuel shortages and environmental problems. Among all alternative energy sources, hydrogen, with its clean combustion, high energy density, and renewability, is widely recognized by the energy sector as the most ideal alternative to fossil fuels, attracting significant attention from countries worldwide.

[0003] There are two main methods for producing hydrogen: chemical and biological. Chemical methods require harsh reaction conditions, are costly, and easily pollute the environment; therefore, biological hydrogen production is the most commonly used technology currently. Biological hydrogen production utilizes the metabolic pathways of microorganisms to produce hydrogen. Its raw materials are mostly industrial and agricultural waste and various industrial wastewaters. This method is not only inexpensive but also purifies wastewater while producing hydrogen, making it a promising area for development and research. However, biological hydrogen production leaves behind a large amount of organic matter, resulting in low energy conversion efficiency in the hydrogen production process. Summary of the Invention

[0004] The present invention aims to provide a wastewater treatment device for dark-light fermentation biohydrogen production, in order to improve the problem that biohydrogen production causes a large amount of organic matter residue, resulting in low energy conversion efficiency in the hydrogen production process.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in the embodiments of this application is:

[0006] In a first aspect, embodiments of this application provide a wastewater treatment device employing dark-light fermentation, comprising a dark fermentation component, a light fermentation component, and a nitrification reactor. The dark fermentation component includes a dark fermentation reactor, within which a first separator is installed. The light fermentation component includes several parallel-connected light fermentation reactors, which are connected to the dark fermentation reactor via a first channel for wastewater separated by the first separator; a separation component is installed within the light fermentation reactor. A second channel connects the nitrification reactor to the light fermentation reactor, and this second channel is used for wastewater separated by the separation component; a third channel connects the nitrification reactor to the dark fermentation reactor, and this third channel is used for a portion of the wastewater generated during the nitrification reaction.

[0007] In some embodiments, the photofermentation reactor includes a first reaction zone, a second reaction zone, and a separation zone; the separation assembly includes a second separator and a third separator. The second separator is disposed between the first reaction zone and the second reaction zone, and is used to separate a portion of the wastewater generated in the first reaction zone into the second reaction zone. The third separator is disposed between the second reaction zone and the separation zone, and is used to separate a portion of the gas and a portion of the wastewater generated in the second reaction zone into the separation zone.

[0008] In some embodiments, the wastewater treatment device further includes a support, a first bracket, and a first slot plate. The first bracket is disposed on the support, one end of the first slot plate is disposed on the support, and the other end is supported by the first bracket. The photo-fermentation reactor is disposed on the first slot plate, and the first slot plate and the support have a first tilt angle, the first bracket being configured to adjust the size of the first tilt angle.

[0009] In some embodiments, the convex surface of the first card slot is provided with a light-concentrating organic coating.

[0010] In some embodiments, the wastewater treatment device further includes several clamps, which are fitted onto the photo-fermentation reactor and fixed to the first clamping tray.

[0011] In some embodiments, the wastewater treatment device further includes a second support and a second slot plate; the second support is disposed on the support, and the second slot plate is disposed opposite to the first slot plate, with one end of the second slot plate disposed on the support and the other end supported by the second support. A plurality of photo-fermentation reactors are disposed on the second slot plate, and the dark fermentation assembly is disposed between the first slot plate and the second slot plate. A second tilt angle is formed between the second slot plate and the support, and the second support is configured to adjust the size of the second tilt angle.

[0012] In some embodiments, the photo-fermentation reactor includes a transparent cylindrical body, in which both the first reaction zone and the second reaction zone are disposed. The transparent cylindrical body is made of PMMA modified with graphene.

[0013] In some embodiments, a gas recovery component is provided at the top of the dark fermentation reactor, the gas recovery component including a molecular sieve for separating gases.

[0014] In some embodiments, the wastewater treatment apparatus further includes a vacuum hood, and the gas recovery component is disposed inside the vacuum hood.

[0015] In some embodiments, the photo-fermentation reactor further includes a first circulating water outlet and a second circulating water outlet, wherein the first circulating water outlet is connected to the first reaction zone and the second circulating water outlet is connected to the separation zone.

[0016] Unlike related technologies, the beneficial effects of the wastewater treatment device using dark-light fermentation provided in this application embodiment are:

[0017] The dark fermentation reactor can produce hydrogen through dark fermentation, generating small molecule acids. The photofermentation reactor can produce hydrogen through photofermentation. The photofermentation reactor and the dark fermentation reactor are connected through a first channel. The photofermentation reaction can use the small molecule acids produced by the dark fermentation reaction as a carbon source for hydrogen production metabolism. The small molecule acids are converted into hydrogen and carbon dioxide during the photofermentation hydrogen production process, so that the residues of the dark fermentation reaction can be reused. At the same time, wastewater and gas can be separated by a separation component. Combining dark fermentation and photofermentation for hydrogen production can significantly improve substrate conversion efficiency and reduce environmental pollution caused by residual tailings. Simultaneously, hydrogen sulfide produced during dark fermentation is converted to sulfate through photofermentation, reducing the biotoxicity of the wastewater. Furthermore, a third channel connects the nitrification reactor and the dark fermentation reactor, allowing the microbial communities involved in dark fermentation and ammonia oxidation to mutually benefit each other. The ammonia nitrogen and nitrite converted from organic nitrogen during dark fermentation are metabolized into nitrogen gas through anaerobic ammonia oxidation, ensuring a low concentration of ammonia nitrogen in the water. The nitrification reactor is then used to supplement nitrite, ensuring the normal operation of the anaerobic ammonia oxidation process and improving hydrogen production efficiency. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0019] Figure 1 This is a front view of a wastewater treatment device provided in an embodiment of this application;

[0020] Figure 2 This is a top view of a wastewater treatment device provided in an embodiment of this application;

[0021] Figure 3 This is a schematic diagram of the structure of a photo-fermentation reactor provided in an embodiment of this application;

[0022] Figure 4 This is a schematic diagram of the structure of a photo-fermentation reactor provided in an embodiment of this application;

[0023] Figure 5 This is a top view of a photo-fermentation reactor provided in an embodiment of this application;

[0024] Figure 6 This is a right view of a wastewater treatment device provided in an embodiment of this application.

[0025] Figure label:

[0026] 11. First card slot; 111. Card slot; 12. Second card slot;

[0027] 21. First support; 22. Second support;

[0028] 30. Support;

[0029] 40. Dark fermentation reactor; 41. First separator; 42. First inlet; 43. First channel;

[0030] 50. Vacuum enclosure; 60. Gas recovery unit; 61. Exhaust gas outlet; 62. Hydrogen outlet; 63. Carbon dioxide outlet; 64. Molecular sieve;

[0031] 70. Photofermentation component; 71. Photofermentation reactor; 711. Separation zone; 7111. Gas outlet; 712. Separation component; 7121. Second separator; 7122. Third separator; 713. First reaction zone; 714. Second reaction zone; 715. Water distributor; 7151. Second water inlet; 716. Transparent cylinder; 7161. First water outlet; 7162. First circulating water outlet; 7163. Second circulating water outlet; 72. Second channel;

[0032] 80. Nitrification reactor; 81. Third channel; 82. First outlet;

[0033] 90. Clamp; 91. First clamp; 92. Second clamp; 93. Third clamp. Detailed Implementation

[0034] To facilitate understanding of the present invention, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "bottom," etc., used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0036] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] The main methods of biological hydrogen production include photocatalytic water splitting, photofermentation, and dark fermentation. Photofermentation is a process in which photosynthetic bacteria utilize light energy to extract electrons and reduce hydrogen through the photodecomposition and metabolism of organic substrates and carbon dioxide. Various photofermentation bacteria can grow heterotrophically and synthesize hydrogen from various volatile fatty acids or wastewater rich in organic acids under light and anaerobic conditions. Dark fermentation utilizes anaerobic bacteria to decompose organic substrates and produce hydrogen under lightless, anaerobic conditions. Dark fermentation hydrogen production can widely use various organic raw materials, including starch, cellulose, lignin, and various organic waste liquids.

[0038] Dark fermentation for hydrogen production can occur without light and at a relatively high rate. However, this process involves the formation of small-molecule acids such as acetic acid, butyric acid, and propionic acid, as well as a certain concentration of ethanol. These volatile fatty acids cannot be utilized by the bacteria to produce hydrogen, resulting in a large amount of organic matter residue in the fermentation broth and low energy conversion efficiency. Furthermore, during bio-fermentation, organic nitrogen continuously undergoes ammoniation. Excessive ammonia nitrogen leads to the production of free ammonia, which is toxic and inhibits anaerobic hydrogen production. The controlled organisms are unstable, and the reaction system is prone to the simultaneous presence of hydrogen-producing and alkylating bacteria.

[0039] This application provides a wastewater treatment device for dark-light fermentation biohydrogen production. This device combines photo-fermentation biohydrogen production with dark fermentation hydrogen production, and couples a nitrification-ammonia oxidation reaction to achieve efficient utilization of wastewater. In this embodiment, the term "wastewater" or similar terms are used to broadly refer to water bodies containing various pollutants that require treatment to avoid pollution problems, without specifically limiting their source or the pollutants they contain.

[0040] In this embodiment, terms such as "outlet" and "inlet" are used to refer to a series of structural devices that enable water to enter or leave a pool, without limiting their specific structural implementation. For example, the inlet / outlet can be a connecting pipe and / or its opening on the side wall, a notch on an adjacent wall, an additional control valve, a flow-controllable connecting pipe / notch, or a pressure pipe that can apply power to drive water to flow in or out, when used in conjunction with a power device such as a water pump.

[0041] Figure 1 This is a schematic diagram of a wastewater treatment device provided in an embodiment of this application, showing the wastewater treatment device from a frontal view. The wastewater treatment device includes: a dark fermentation component (not shown in the figure), a photofermentation component 70, and a nitrification reactor 80.

[0042] The aforementioned dark fermentation component includes a dark fermentation reactor 40, within which a first separator 41 is installed. Specifically, organic wastewater undergoes dark fermentation for biological hydrogen production through the first inlet 42 of the dark fermentation reactor 40. Anaerobic hydrogen-producing bacteria ferment under anaerobic conditions without light, decomposing the organic substrate to produce hydrogen. Simultaneously, anaerobic ammonia-oxidizing bacteria convert organic nitrogen into ammonia nitrogen and nitrite under anaerobic conditions, generating nitrogen gas. By removing ammonia nitrogen from the water, a low ammonia nitrogen concentration is ensured, which has no inhibitory effect on anaerobic hydrogen-producing bacteria, allowing for efficient hydrogen production. The first separator 41 separates the hydrogen, carbon dioxide, nitrogen, and wastewater produced during the dark fermentation biological hydrogen production and anaerobic ammonia oxidation processes. The first separator 41 prevents the loss of hydrogen-producing bacteria within the dark fermentation reactor 40 and simultaneously sends the gas to the gas recovery unit 60. For example, the first separator 41 can be a three-phase separator.

[0043] In some embodiments, combined with Figure 1 and Figure 2 , Figure 2 This is a schematic diagram of a wastewater treatment device provided in an embodiment of this application, showing the wastewater treatment device from a top view. A gas recovery component 60 is installed at the top of the dark fermentation reactor 40. The gas recovery component 60 includes a molecular sieve 64 for gas separation. The molecular sieve 64 has a hydrogen outlet 62, a carbon dioxide outlet 63, and a waste gas outlet 61 installed within it. Specifically, the first separator 41 separates hydrogen, carbon dioxide, nitrogen, and the reacted wastewater. Hydrogen, carbon dioxide, and nitrogen enter the gas recovery component 60. Hydrogen is discharged through the hydrogen outlet 62 and stored in a storage tank. Carbon dioxide enters the carbon fixation reactor through the carbon dioxide outlet 63. After being fixed into organic molecules, the carbon serves as a carbon source for the wastewater denitrification process, ensuring stable operation of the denitrification process. The carbon neutralization reaction in wastewater treatment can be guaranteed without the need for an external carbon source. The remaining gases are discharged from the waste gas outlet 61.

[0044] The aforementioned photo-fermentation component 70 includes several photo-fermentation reactors 71 arranged in parallel. The photo-fermentation reactor 71 is connected to the dark fermentation reactor 40 through a first channel 43. The first channel 43 is used for wastewater separated by the first separator 41. A separation component 712 is provided inside the photo-fermentation reactor 71. There can be one or more separation components 712. One or more separation components 712 can divide the photo-fermentation reactor 71 into different reaction zones.

[0045] Furthermore, combined Figure 3 and Figure 5The separation component 712 includes a second separator 7121 and a third separator 7122, which divide the photo-fermentation reactor 71 into a first reaction zone 713, a second reaction zone 714, and a separation zone 711. The second separator 7121 is located between the first reaction zone 713 and the second reaction zone 714, and is used to separate a portion of the wastewater generated in the first reaction zone 713 into the second reaction zone 714. The third separator 7122 is located between the second reaction zone 714 and the separation zone 711, and is used to separate a portion of the gas and a portion of the wastewater generated in the second reaction zone 714 into the separation zone 711. Wastewater enters the photo-fermentation reactor 71 through the first channel 43 and then through the second inlet 7151. A water distributor 715 evenly distributes the wastewater into the first reaction zone 713. The high-concentration wastewater in the first reaction zone 713 contains small-molecule acids, which undergo hydrogen production metabolism under anaerobic light conditions by photosynthetic bacteria, converting them into hydrogen and carbon dioxide. This reduces the organic carbon content in the wastewater and allows it to be used for hydrogen production. The second separator 7121 separates the gas from the reacted wastewater, while the carrier particles remain in the first reaction zone 713. When the wastewater entering the second reaction zone 714 undergoes photosynthetic hydrogen production, the hydrogen sulfide produced by dark fermentation is oxidized into sulfate by photosynthetic bacteria, reducing the biotoxicity of the water and decreasing the energy consumption of the blower used to strip hydrogen sulfide. The generated gas can be separated by the third separator 7122. The gas generated in the above process enters the gas recovery unit 60 through the gas outlet 7111 of the photo-fermentation reactor 71.

[0046] In some embodiments, the second separator 7121 and the third separator 7122 can be three-phase separators. The three-phase separators can trap the carrier particles in the first reaction zone 713 and / or the second reaction zone 714 to separate wastewater and gas. By agitating and stirring the inside of the photo-fermentation reactor 71, the contact area between the carrier particles and wastewater in the photo-fermentation reactor 71 is increased, thereby enhancing the efficiency of photo-fermentation biohydrogen production.

[0047] In some embodiments, carrier particles are distributed in a suitable ratio to the first reaction zone 713 and the second reaction zone 714. For example, the ratio of carrier particles in the first reaction zone 713 to the second reaction zone 714 is 6:4, or the ratio of carrier particles in the first reaction zone 713 to the second reaction zone 714 is 7:3, so as to maximize the utilization efficiency of the carrier particles.

[0048] In some embodiments, see Figure 4 and Figure 5The photo-fermentation reactor 71 also includes a first circulating outlet 7162 and a second circulating outlet 7163. The first circulating outlet 7162 is connected to the first reaction zone 713, and the second circulating outlet 7163 is connected to the separation zone 711. Optionally, the first circulating outlet 7162 can be located at the bottom of the first reaction zone 713 and close to the water distributor 715, and the second circulating outlet 7163 can be located at the bottom of the separation zone 711 and close to the third separator 7122, thereby expanding the wastewater circulation area. Part of the wastewater is externally circulated through the first circulating outlet 7162 and the second circulating outlet 7163, ensuring the overall water flow residence time in the photo-fermentation reactor 71, increasing the contact area between the wastewater and the carrier particles, and reducing energy waste. Appropriately increasing the hydraulic stirring capacity can ensure the overall reactor efficiency.

[0049] For the nitration reactor 80 mentioned above, please refer to Figure 6 , Figure 6 This is a schematic diagram of a wastewater treatment device provided in an embodiment of this application, showing the wastewater treatment device from a side view. A second channel 72 connects the nitrification reactor 80 and the photo-fermentation reactor 71, and the second channel 72 is used for wastewater separated by the separation component 712; a third channel 81 connects the nitrification reactor 80 and the dark fermentation reactor 40, and the third channel 81 is used for part of the wastewater generated by the nitrification reaction. Specifically, wastewater is discharged from the first outlet 7161 of the photo-fermentation reactor 71. The wastewater discharged from each photo-fermentation reactor 71 is collected in the second channel 72 of the photo-fermentation component 70 and enters the nitrification reactor 80 for nitrification to produce nitrite. Part of the wastewater after nitrification is reused and enters the dark fermentation reactor 40 through the third channel 81. Anaerobic ammonia oxidizing bacteria use the ammonia nitrogen converted from organic nitrogen under anaerobic conditions and the nitrite entering through the third channel 81 of the nitrification reactor 80 to produce nitrogen gas, which can remove ammonia nitrogen from the water, reduce the free ammonia produced during the reaction, and promote the efficiency of hydrogen production by the dark fermentation bacteria. The remaining wastewater can be discharged from the first outlet 82 of the nitrification reactor 80 to the denitrification reactor 80.

[0050] The photofermentation reactor 71 addresses the problem of low energy conversion efficiency in hydrogen production during dark fermentation, where volatile fatty acids cannot be utilized by dark fermentation bacteria, resulting in a large amount of residual organic matter. Under anaerobic light conditions, the photosynthetic bacteria in the reactor 71 can metabolize hydrogen using small-molecule acids as a carbon source. These small-molecule acids are converted into hydrogen and carbon dioxide in the photosynthetic bacteria's hydrogen production system. Combining dark fermentation and photofermentation for biological hydrogen production significantly improves substrate conversion efficiency, reduces environmental pollution from residual tailings, and reduces the biotoxicity of wastewater by oxidizing hydrogen sulfide produced during dark fermentation to sulfate by photosynthetic bacteria. Furthermore, the excessive energy consumption of blowers during hydrogen sulfide stripping removal is reduced.

[0051] In the absence of a light source, compared to the combined method of dark fermentation and photofermentation for hydrogen production, the photofermentation reactor 71 no longer performs photofermentation for biological hydrogen production. Wastewater enters the dark fermentation reactor 40 for dark fermentation hydrogen production. The small-molecule acidic organic matter produced during the reaction is utilized by the denitrification process in the nitrification reactor 80 and can then be used as a carbon source to supplement the dark fermentation reactor 40.

[0052] In some embodiments, the wastewater treatment device further includes a support 30, a first bracket 21, and a first slot plate 11. The first bracket 21 is disposed on the support 30, one end of the first slot plate 11 is disposed on the support 30, and the other end is supported by the first bracket 21. The photo-fermentation reactor 71 is disposed on the first slot plate 11. The first slot plate 11 and the support 30 have a first tilt angle. The first bracket 21 is configured to adjust the size of the first tilt angle. Under natural light or an external light source, by adjusting the size of the first tilt angle of the first bracket 21, the photo-fermentation reactor 71 can obtain the optimal light angle.

[0053] In some embodiments, the first slot plate 11 is made of aluminum alloy and serves to support the photo-fermentation reactor 71. The lightweight nature of the aluminum alloy ensures a high remaining support capacity for the first support 21 and the base 30, thus providing a buffering effect. The convex surface of the first slot plate 11 is coated with a light-concentrating organic coating, which increases the light intake of the photo-fermentation reactor 71, enhances the light energy utilization effect, and improves the hydrogen production efficiency of photosynthetic bacteria.

[0054] In some embodiments, the first slot plate 11 is provided with a slot 111, and the photo-fermentation reactor 71 can be partially locked in the slot 111. The wastewater treatment device also includes several clamps 90, which are sleeved on the photo-fermentation reactor 71 and fixed to the first slot plate 11. For details, please refer to [link to relevant documentation]. Figure 2 The photo-fermentation reactor 71 is equipped with a first clamp 91, a second clamp 92 and a third clamp 93. The first clamp 91 and the third clamp 93 are located at both ends of the photo-fermentation reactor 71, and the second clamp 92 is located in the middle of the photo-fermentation reactor 71. By setting clamps 90 at different parts of the photo-fermentation reactor 71, the stability and safety of the photo-fermentation reactor 71 when tilted are ensured.

[0055] In some embodiments, the wastewater treatment device further includes a second support 22 and a second slot plate 12. The second support 22 is disposed on a support 30, and the second slot plate 12 is disposed opposite to the first slot plate 11. One end of the second slot plate 12 is disposed on the support 30, and the other end is supported by the second support 22. A plurality of photo-fermentation reactors 71 are disposed on the second slot plate 12, and a dark fermentation component is disposed between the first slot plate 11 and the second slot plate 12. The second slot plate 12 and the support 30 have a second tilt angle, and the second support 22 is configured to adjust the size of the second tilt angle. The size of the first tilt angle and the size of the second tilt angle can be the same angle or different angles. By adjusting the size of the first tilt angle and the size of the second tilt angle, the photo-fermentation reactors 71 can obtain the optimal light angle. By placing the photo-fermentation reactors 71 on both sides of the dark fermentation component, the photo-fermentation reactors 71 are ensured to maximize the utilization of light for photosynthesis.

[0056] In some embodiments, the photofermentation reactor 71 is cylindrical, comprising a transparent cylinder 716. Several transparent cylinders 716 are connected in parallel to form a high-efficiency photofermentation component 70, which can maximize the utilization of light energy. The large specific surface area provides an advantage for microorganisms in the photofermentation reactor 71 to utilize light energy, resulting in better heat and mass transfer within the photofermentation reactor 71. The first reaction zone 713 and the second reaction zone 714 are both disposed within the transparent cylinder 716. The transparent cylinder 716 is made of graphene-modified PMMA (polymethyl methacrylate), giving it strong light transmittance and light-concentrating properties.

[0057] In some embodiments, the wastewater treatment device further includes a vacuum hood 50, and a gas recovery component 60 is disposed inside the vacuum hood 50. The vacuum hood 50 can prevent factors such as sunlight causing the gas recovery component 60 to overheat, thus ensuring the stability of the gas.

[0058] The wastewater treatment device for dark-to-light fermentation biohydrogen production provided in this application embodiment includes a dark fermentation reactor 40 for dark fermentation hydrogen production, where the dark fermentation reaction generates small molecule acids; and a light fermentation reactor 71 for light fermentation hydrogen production. The light fermentation reactor 71 and the dark fermentation reactor 40 are connected via a first channel 43. The light fermentation reaction utilizes the small molecule acids produced by the dark fermentation reaction as a carbon source for hydrogen production metabolism. During the light fermentation hydrogen production process, the small molecule acids are converted into hydrogen and carbon dioxide, allowing the residues of the dark fermentation reaction to be reused and improving energy conversion efficiency. Simultaneously, the wastewater and gas can be separated by a separation component 712. Combining dark fermentation and photofermentation for hydrogen production can significantly improve substrate conversion efficiency and reduce environmental pollution caused by residual tailings. Simultaneously, hydrogen sulfide produced during dark fermentation is converted to sulfate through photofermentation, reducing the biotoxicity of the wastewater. Furthermore, a third channel 81 connects the nitrification reactor 80 to the dark fermentation reactor, allowing the microbial communities involved in dark fermentation and ammonia oxidation to mutually benefit each other. The ammonia nitrogen and nitrite converted from organic nitrogen during dark fermentation are metabolized into nitrogen gas through anaerobic ammonia oxidation, ensuring a low concentration of ammonia nitrogen in the water. Nitrite is supplemented using the nitrification reactor 80, ensuring the normal operation of the anaerobic ammonia oxidation process and improving hydrogen production efficiency.

[0059] To fully illustrate the actual performance of the wastewater treatment device provided in this application, specific embodiments are described below.

[0060] Example 1:

[0061] Taking wool textile wastewater treatment as an example, the wool scouring wastewater, after efficient coagulation and sedimentation, enters the dark fermentation reactor 40 through the first inlet 42. The wastewater undergoes hydrolysis and dark fermentation to produce hydrogen. Wastewater, gas, and carrier are separated by the first separator 41 of the dark fermentation reactor 40. The gas enters the gas recovery unit 60. Wastewater flows into the photo-fermentation reactor 71 through the first channel 43. The wastewater enters from the second inlet 7151 of the photo-fermentation reactor 71 and is evenly distributed into the first reaction zone 713 using a water distributor 715. The high-concentration wastewater in the first reaction zone 713 contains small-molecule acids, which undergo hydrogen production metabolism under anaerobic light conditions by photosynthetic bacteria. Wastewater, gas, and carrier are separated by the second separator 7121. The wastewater enters the second reaction zone 714 for deep photosynthetic hydrogen production and removal of hydrogen sulfide from the water. After the reaction, the wastewater, gas, and carrier are separated by the third separator 7122. The gas and wastewater enter the separation zone 711. Part of the wastewater is recycled through the first circulation outlet 7162 and the second circulation outlet 7163, while the remaining wastewater is discharged through the first outlet 7161. The collected wastewater enters the nitrification reactor 80 through the second channel 72 for nitrification. Part of the wastewater after nitrification enters the dark fermentation reactor 40 through the third channel 81. Anaerobic ammonia oxidizing bacteria use the ammonia nitrogen converted from organic nitrogen under anaerobic conditions and the nitrite entering through the third channel 81 of the nitrification reactor 80 to produce nitrogen gas. The gas is separated through the first separator 41 of the dark fermentation reactor 40 and enters the gas recovery component 60. The remaining wastewater is discharged into the denitrification reactor 80 through the first outlet 82.

[0062] After entering the gas recovery unit 60, the gas is separated by molecular sieve 64. Hydrogen is discharged through hydrogen outlet 62 and stored in storage tank. Carbon dioxide enters carbon fixation reactor through carbon dioxide outlet 63. After carbon is fixed into organic molecules, it can be used as a carbon source in the wastewater denitrification process section. The remaining gas is discharged from waste gas outlet 61.

[0063] Equipment tests conducted using wool scouring wastewater showed that the solar energy conversion efficiency during hydrogen production reached 20.3%, the total carbon utilization conversion rate reached 75.3%, and the total nitrogen removal rate reached 62.43%.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above. For the sake of brevity, they are not provided in detail; although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some 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 this application.

Claims

1. A wastewater treatment device employing dark-light fermentation for biological hydrogen production, characterized in that, include: A dark fermentation assembly includes a dark fermentation reactor, wherein a first separator is provided inside the dark fermentation reactor; The photo-fermentation component includes several photo-fermentation reactors arranged in parallel. The photo-fermentation reactors are connected to the dark fermentation reactors through a first channel, which is used for wastewater separated by the first separator. A separation component is provided inside the photo-fermentation reactors. The nitrification reactor is connected to the photo-fermentation reactor by a second channel, which is used for wastewater separated by the separation component; the nitrification reactor is connected to the dark fermentation reactor by a third channel, which is used for some of the wastewater generated by the nitrification reaction. The photo-fermentation reactor includes a first reaction zone, a second reaction zone, and a separation zone; the separation assembly includes a second separator and a third separator; the second separator is disposed between the first reaction zone and the second reaction zone, and is used to separate a portion of the wastewater generated in the first reaction zone to the second reaction zone; the third separator is disposed between the second reaction zone and the separation zone, and is used to separate a portion of the gas and a portion of the wastewater generated in the second reaction zone to the separation zone.

2. The wastewater treatment device according to claim 1, characterized in that, The wastewater treatment device also includes a support, a first bracket, and a first slot plate; The first bracket is disposed on the support, one end of the first slot plate is disposed on the support, and the other end is supported by the first bracket; The photo-fermentation reactor is disposed on the first slot plate, and the first slot plate and the support have a first tilt angle. The first support is configured to adjust the size of the first tilt angle.

3. The wastewater treatment device according to claim 2, characterized in that, The convex surface of the first card slot is provided with a light-concentrating organic coating.

4. The wastewater treatment device according to claim 2, characterized in that, The wastewater treatment device also includes several clamps, which are fitted onto the photo-fermentation reactor and fixed to the first clamping tray.

5. The wastewater treatment device according to claim 2, characterized in that, The wastewater treatment device also includes a second support and a second card slot. The second bracket is disposed on the support, the second slot plate is disposed opposite to the first slot plate, one end of the second slot plate is disposed on the support, and the other end is supported by the second bracket; The second slot is provided with a plurality of light fermentation reactors, and the dark fermentation component is disposed between the first slot and the second slot; The second slot plate has a second tilt angle with the support, and the second bracket is configured to adjust the size of the second tilt angle.

6. The wastewater treatment device according to claim 1, characterized in that, The photo-fermentation reactor includes a transparent cylindrical body, in which both the first reaction zone and the second reaction zone are disposed. The transparent cylindrical body is made of PMMA modified with graphene.

7. The wastewater treatment device according to claim 1, characterized in that, The dark fermentation reactor is equipped with a gas recovery component at the top, which includes a molecular sieve for separating gases.

8. The wastewater treatment apparatus according to claim 7, characterized in that, The wastewater treatment device also includes a vacuum chamber, and the gas recovery component is disposed inside the vacuum chamber.

9. The wastewater treatment apparatus according to claim 1, characterized in that, The photo-fermentation reactor further includes a first circulating water outlet and a second circulating water outlet, the first circulating water outlet being connected to the first reaction zone and the second circulating water outlet being connected to the separation zone.

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