A dark-light two-stage hydrogen production system for treating organic wastewater

Abstract

The invention discloses a dark-light two-stage hydrogen production system for treating organic wastewater, relates to the technical field of wastewater treatment, comprises a dark fermentation reaction zone, a light fermentation reaction zone and a pretreatment zone, wherein a water inlet of the dark fermentation reaction zone is used for inputting wastewater to be treated, a water outlet of the dark fermentation reaction zone is connected with a water inlet of the light fermentation reaction zone through the pretreatment zone, a common gas outlet is arranged on the top of the dark fermentation reaction zone and the light fermentation reaction zone; a water inlet of a first three-phase separator is connected with a water outlet of the light fermentation reaction zone, and a gas outlet of the first three-phase separator is connected with a gas outlet shared by the dark fermentation reaction zone and the light fermentation reaction zone; in the invention, the pretreatment zone can adjust the physical and chemical properties of the product of the dark fermentation reaction zone before entering the light fermentation reaction zone, such as adjusting the organic acid concentration, pH, ammonia nitrogen concentration, etc., so as to reduce or even avoid the influence of the product of the dark fermentation reaction zone on the hydrogen production efficiency in the light fermentation reaction zone, and improve the organic wastewater treatment and hydrogen production efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a dark-light two-stage hydrogen production system for treating organic wastewater. Background Art

[0002] Different from conventional biological hydrogen production systems that use dark fermentation alone, light fermentation, or dark-light mixed fermentation, dark-light two-stage fermentation hydrogen production is to degrade organic matter in sewage and fully convert wastewater into hydrogen under the action of hydrolytic acid-producing hydrogen-producing bacteria and photosynthetic bacteria in sequence. Current research shows that two-stage hydrogen production fermentation has a higher ability to withstand organic loads and higher hydrogen production efficiency than conventional anaerobic fermentation.

[0003] However, the hydrogen production efficiency of the current two-stage hydrogen production reactor is still relatively low. Therefore, how to improve the organic wastewater treatment efficiency and hydrogen production efficiency of the dark-light two-stage hydrogen production system and achieve effective collection of hydrogen is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0004] The purpose of the present invention is to provide a dark-light two-stage hydrogen production system for treating organic wastewater, so as to solve the problems existing in the above-mentioned prior art, and to achieve effective collection of hydrogen while improving the organic wastewater treatment efficiency and hydrogen production efficiency of the dark-light two-stage hydrogen production system.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a dark-light two-stage hydrogen production system for treating organic wastewater, comprising a dark fermentation reaction zone, a light fermentation reaction zone and a pretreatment zone, wherein the water inlet of the dark fermentation reaction zone is used to input wastewater to be treated, and the water outlet of the dark fermentation reaction zone is connected to the water inlet of the light fermentation reaction zone through the pretreatment zone;

[0007] The pretreatment zone can adjust the physical and chemical properties of the product of the dark fermentation reaction zone to reduce the inhibitory effect of the product of the dark fermentation reaction zone on the growth and metabolism of microorganisms in the light fermentation reaction zone;

[0008] Wherein, the physicochemical properties of the product of the dark fermentation reaction zone include organic acid concentration, and / or pH, and / or ammonia nitrogen concentration;

[0009] A common gas outlet is provided at the top of the dark fermentation reaction zone and the top of the light fermentation reaction zone; the water outlet of the light fermentation reaction zone is connected to the water inlet of the first three-phase separator, and the common gas outlet of the dark fermentation reaction zone and the light fermentation reaction zone is connected to the gas outlet of the first three-phase separator.

[0010] Preferably, a water distributor is provided in the pretreatment zone, and the water outlet of the dark fermentation reaction zone is connected with the water inlet of the light fermentation reaction zone through the water distributor;

[0011] And / or, a pH adjustment unit is provided in the pretreatment zone to adjust the pH of the product in the dark fermentation reaction zone;

[0012] And / or, an ammonia nitrogen treatment section is provided in the pretreatment zone, and the ammonia nitrogen treatment section is used to reduce the ammonia nitrogen concentration in the product of the dark fermentation reaction zone.

[0013] Preferably, the volume ratio of the light fermentation reaction zone to the dark fermentation reaction zone is 3-10.

[0014] Preferably, the dark-light two-stage hydrogen production system further comprises an illumination component for providing the required illumination to the light fermentation reaction zone, and the illumination component is arranged to avoid the dark fermentation reaction zone;

[0015] And / or, a photosensitive material is provided in the photofermentation reaction zone.

[0016] Preferably, a first carrier filler for attachment of microorganisms in the dark fermentation reaction zone is provided in the dark fermentation reaction zone;

[0017] And / or, a second carrier filler for attachment of microorganisms in the photofermentation reaction zone is provided in the photofermentation reaction zone.

[0018] Preferably, a second three-phase separator is provided in the photo-fermentation reaction zone, and the second three-phase separator is arranged below the water outlet of the photo-fermentation reaction zone;

[0019] And / or, the inclination angle of the sedimentation zone of the second three-phase separator is 45°-80°.

[0020] Preferably, the light fermentation reaction zone and the dark fermentation reaction zone are arranged integrally.

[0021] Preferably, the dark fermentation reaction zone and the light fermentation reaction zone are arranged in sequence from the inside to the outside, the water outlet of the dark fermentation reaction zone is located at the bottom of the dark fermentation reaction zone, and the water outlet of the light fermentation reaction zone is located at the top of the light fermentation reaction zone.

[0022] Compared with the prior art, the present invention has achieved the following technical effects:

[0023] In the present invention, the water outlet of the dark fermentation reaction zone and the water inlet of the light fermentation reaction zone are connected through the pretreatment zone, so that the wastewater to be treated can enter the light fermentation reaction zone after being treated in the dark fermentation reaction zone, thereby realizing dark-light two-stage hydrogen production; and the pretreatment zone in the present invention can pretreat the products of the dark fermentation reaction zone before entering the light fermentation reaction zone, for example, by adjusting the pH, organic acid concentration, reducing the ammonia nitrogen concentration, etc., so that the products of the dark fermentation reaction zone entering the light fermentation reaction zone will not significantly inhibit the growth and metabolism of microorganisms in the light fermentation reaction zone, and will not significantly reduce the wastewater treatment efficiency and hydrogen production efficiency of the light fermentation reaction. In other words, the pretreatment zone in the present invention reduces or even avoids the negative impact of the products of the dark fermentation reaction zone on the hydrogen production in the light fermentation reaction zone, thereby improving the wastewater treatment efficiency and hydrogen production efficiency of the dark-light two-stage hydrogen production system for treating organic wastewater;

[0024] At the same time, the first three-phase separator performs three-phase separation on the product discharged from the water outlet of the light reaction zone, thereby achieving effective collection of hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the structure of a dark-light two-stage hydrogen production system for treating organic wastewater;

[0027] Among them, 1. dark-light integrated reactor; 2. first three-phase separator; 3. illumination component; 11. dark fermentation reaction zone; 12. light fermentation reaction zone; 13. water inlet pipe; 14. first carrier filler; 15. water outlet of light fermentation reaction zone; 16. second three-phase separator; 17. bacteria collection port; 18. water distributor; 19. air outlet; 21. water inlet of first three-phase separator; 22. water outlet of first three-phase separator; 23. air outlet of first three-phase separator; 24. bacteria collection port of first three-phase separator. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figure 1 As shown, the present invention discloses a dark-light two-stage hydrogen production system for treating organic wastewater, comprising a dark fermentation reaction zone 11, a light fermentation reaction zone 12 and a pretreatment zone, wherein the water inlet of the dark fermentation reaction zone 11 is used to input wastewater to be treated, and the water outlet of the dark fermentation reaction zone 11 is connected with the water inlet of the light fermentation reaction zone 12 through the pretreatment zone; the pretreatment zone can adjust the physicochemical properties of the product of the dark fermentation reaction zone 11 to reduce the inhibitory effect of the product of the dark fermentation reaction zone 11 on the growth and metabolism of microorganisms in the light fermentation reaction zone; the physicochemical properties of the product of the dark fermentation reaction zone 11 include organic acid concentration, and / or pH, and / or ammonia nitrogen concentration; the top of the dark fermentation reaction zone 11 and the top of the light fermentation reaction zone 12 are provided with a common gas outlet; the water outlet 15 of the light fermentation reaction zone is connected with the water inlet of the first three-phase separator 2, and the gas outlet 19 shared by the dark fermentation reaction zone 11 and the light fermentation reaction zone 12 is connected with the gas outlet of the first three-phase separator 2.

[0031] The pretreatment zone can adjust the physical and chemical properties of the product of the dark fermentation reaction zone 11, thereby reducing the inhibitory effect of the product of the dark fermentation reaction zone 11 on the growth and metabolism of microorganisms in the light fermentation reaction zone 12. The physical and chemical properties of the product of the dark fermentation reaction zone include organic acid concentration, and / or pH, and / or ammonia nitrogen concentration.

[0032] In the present invention, the water outlet of the dark fermentation reaction zone is connected to the water inlet of the light fermentation reaction zone 12 through the pretreatment zone, so that the wastewater to be treated can enter the light fermentation reaction zone 12 after being treated in the dark fermentation reaction zone 11, thereby realizing dark-light two-stage hydrogen production; and the pretreatment zone in the present invention can pretreat the products of the dark fermentation reaction zone 11 before entering the light fermentation reaction zone 12, for example, by adjusting the pH, organic acid concentration, reducing the ammonia nitrogen concentration, etc., so that the products of the dark fermentation reaction zone 11 entering the light fermentation reaction zone 12 will not significantly reduce the growth metabolism of microorganisms in the light fermentation reaction zone, and will not significantly reduce the wastewater treatment efficiency and hydrogen production efficiency of the light fermentation reaction. In other words, the pretreatment zone in the present invention reduces or even avoids the negative impact of the products of the dark fermentation reaction zone 11 on the hydrogen production in the light fermentation reaction zone 12, thereby improving the wastewater treatment efficiency and hydrogen production efficiency of the dark-light two-stage hydrogen production system for organic wastewater;

[0033] At the same time, the first three-phase separator 2 performs three-phase separation on the product discharged from the water outlet 15 of the photofermentation reaction zone, thereby achieving effective collection of hydrogen.

[0034] The dark fermentation reaction zone 11 is provided with microorganisms required for completing the dark fermentation reaction, and the light fermentation reaction zone 12 is provided with microorganisms required for completing the light fermentation reaction. The pretreatment zone can adjust the physical and chemical properties of the product of the dark fermentation reaction zone 11 to reduce the inhibitory effect of the product of the dark fermentation reaction zone on the growth and metabolism of the microorganisms in the light fermentation reaction zone. The physical and chemical properties of the product of the dark fermentation reaction zone 11 include organic acid concentration, and / or pH, and / or ammonia nitrogen concentration. The pretreatment zone can reduce the ammonia nitrogen concentration and / or organic acid concentration of the dark fermentation reaction zone 11 products that are about to enter the photofermentation reaction zone 12, and / or the pretreatment zone adjusts the pH of the dark fermentation reaction zone 11 products that are about to enter the photofermentation reaction zone 12 to prevent the dark fermentation reaction zone 11 products that are about to enter the photofermentation reaction zone 12 from being too acidic; but this does not mean that the pretreatment zone can only adjust the pH, organic acid concentration and ammonia nitrogen concentration of the dark fermentation reaction zone 11 products that are about to enter the photofermentation reaction zone 12, and can also pretreat other physical and chemical properties of the dark fermentation reaction zone 11 products that are about to enter the photofermentation reaction zone 12 that may reduce the hydrogen production efficiency in the photofermentation reaction zone 12.

[0035] The pretreatment area is provided with at least one of a water distributor 18, a pH adjustment unit and an ammonia nitrogen treatment unit. The pretreatment area has various forms to realize the function of "reducing or even avoiding the negative impact of the dark fermentation reaction area 11 products entering the light fermentation reaction area 12 on the growth metabolism of microorganisms in the light fermentation reaction area 12, the wastewater treatment efficiency and the hydrogen production efficiency". The pretreatment area can be set at different positions according to different forms of the pretreatment area and working conditions.

[0036] For example, when a water distributor 18 is provided in the pretreatment zone, the product of the dark fermentation reaction zone 11 is evenly distributed in the light fermentation reaction zone 12 through the water distributor 18, which reduces the concentration of ammonia nitrogen and organic acid (such as acetic acid and butyric acid) in the light fermentation reaction zone 12, and avoids the ammonia nitrogen and organic acid in the product of the dark fermentation reaction zone 11 being concentrated in the local area of ​​the light fermentation reaction zone 12, resulting in excessive ammonia nitrogen concentration and organic acid concentration in the local area of ​​the light fermentation reaction zone 12, causing the growth and metabolism of microorganisms in the local area of ​​the light fermentation reaction zone 12 to be greatly inhibited, and the wastewater treatment efficiency and hydrogen production efficiency are low. However, when only a water distributor 18 is provided in the pretreatment zone, the pretreatment zone can be set at the water inlet of the light fermentation reaction zone 12, or, when the water outlet of the dark fermentation reaction zone is directly connected to the inlet of the light fermentation reaction zone 12, the pretreatment zone can be set at the water outlet of the dark fermentation reaction zone, or, the pretreatment zone can also be set at the water inlet of the light fermentation reaction zone 12.

[0037] And / or, a pH adjusting unit is provided in the pretreatment zone, and the pH adjusting unit is used to adjust the pH of the product of the dark fermentation reaction zone 11, so as to avoid the product of the dark fermentation reaction zone 11 entering the light fermentation reaction zone 12 from being too acidic, thereby inhibiting the growth and metabolism of microorganisms, wastewater treatment efficiency and hydrogen production efficiency in the light fermentation reaction zone 12. When only a pH adjusting unit is provided in the pretreatment zone, the pretreatment zone can be provided at the water outlet of the dark fermentation reaction zone, on the channel connecting the water outlet 15 of the dark fermentation reaction zone and the water inlet of the light fermentation reaction zone 12, or at the water inlet of the light fermentation reaction zone 12. The pH adjusting unit can specifically be a pH adjusting agent, or other structure that can reduce the pH of the product of the dark fermentation reaction zone.

[0038] And / or, an ammonia nitrogen treatment unit is provided in the pretreatment zone, and the ammonia nitrogen treatment unit is used to reduce the ammonia nitrogen concentration in the product of the dark fermentation reaction zone 11. The ammonia nitrogen treatment unit can be a structure such as activated carbon, biochar or water treatment membrane assembly, which reduces the ammonia nitrogen concentration of the product of the dark fermentation reaction zone 11 by filtering, adsorption and the like, or other structures that can reduce the ammonia nitrogen concentration of the product of the dark fermentation reaction zone 11 entering the light fermentation reaction zone 12; by reducing the ammonia nitrogen concentration of the product of the dark fermentation reaction zone 11 entering the light fermentation reaction zone 12, it is avoided that the ammonia nitrogen concentration in the light fermentation reaction zone 12 is too high to inhibit the growth metabolism of microorganisms in the light fermentation reaction zone 12, the wastewater treatment efficiency and the hydrogen production efficiency.

[0039] It should be noted that the pretreatment zone can be equipped with not only a water distributor 18, a pH adjustment unit or an ammonia nitrogen treatment unit; other structures or reagents that can pretreat the products of the dark fermentation reaction zone 11 can also be set up to "reduce or even avoid the negative impact of the products of the dark fermentation reaction zone 11 entering the light fermentation reaction zone 12 on the growth metabolism of microorganisms in the light fermentation reaction zone 12, the wastewater treatment efficiency and the hydrogen production efficiency." Moreover, the above content only describes the location of the pretreatment zone when only a water distributor 18, a pH adjustment unit or an ammonia nitrogen treatment unit is provided in the pretreatment zone; when at least two functional structures are provided in the pretreatment zone (the functional structure refers to the water distributor 18, the pH adjustment unit, the ammonia nitrogen treatment unit, or other structures or reagents that can reduce or even avoid the products of the dark fermentation reaction zone 11 entering the photo-fermentation reaction zone 12 and inhibiting the growth metabolism of microorganisms in the photo-fermentation reaction zone 12, the wastewater treatment efficiency and the hydrogen production efficiency), it is necessary to comprehensively consider the functional structure and working conditions in the pretreatment zone, and flexibly adjust the location of the pretreatment zone to ensure the smooth realization of the function of "reducing or even avoiding the products of the dark fermentation reaction zone 11 entering the photo-fermentation reaction zone 12 to inhibit the growth metabolism of microorganisms in the photo-fermentation reaction zone 12, and reduce the wastewater treatment efficiency and the hydrogen production efficiency".

[0040] And / or, the pretreatment zone in the present invention may also be a structure capable of performing centrifugation, sedimentation, nitrification and denitrification treatment or anaerobic ammonia oxidation treatment on the product of the dark fermentation reaction zone 11.

[0041] The "and / or" in the present invention means that the text content located before and / or and the text content located after and / or can exist at the same time. For example, A and / or B means that A and B can exist at the same time, or only A or B can exist. The meaning of "and / or" is the same as that of "and / or", which will not be repeated here.

[0042] Furthermore, in the present invention, the volume ratio of the photofermentation reaction zone 12 to the dark fermentation reaction zone 11 can be specifically 3-10, which makes the growth and metabolic rate of the microorganisms in the photofermentation reaction zone 12 match the growth and metabolic rate of the microorganisms in the dark fermentation reaction zone 11, avoids the excessively high product concentration in the dark fermentation reaction zone 11 inhibiting the photofermentation reaction, and ensures that the photofermentation reaction zone 12 has a high wastewater treatment efficiency and hydrogen production efficiency; at the same time, the larger volume of the photofermentation reaction zone 12 allows the product of the dark fermentation reaction zone 11 to play a dilution role after entering the photofermentation reaction zone 12, avoids the product concentration of the dark fermentation reaction zone 11 entering the photofermentation reaction zone 12 being too high, and inhibiting the growth metabolism of the microorganisms, wastewater treatment efficiency and hydrogen production efficiency in the photofermentation reaction zone 12.

[0043] The light fermentation reaction zone 12 and the dark fermentation reaction zone 11 in the present invention are arranged as one body, which not only integrates the two processes of dark fermentation acid production and hydrogen production and light fermentation acid production and hydrogen production in one reactor in stages, but also can realize the continuous production of hydrogen by dark fermentation and light fermentation in an integrated manner. By integrating the two processes of dark fermentation acid production and hydrogen production and light fermentation acid production and hydrogen production in one reactor in stages, the required space area is smaller than that of a two-stage separation system, and the organic matter in the organic wastewater can be effectively degraded while achieving efficient hydrogen production. The organic matter removal effect and hydrogen production efficiency of the unit volume reactor are also higher than those of a two-stage separation system. Moreover, this also improves the space occupancy rate of the dark-light two-stage hydrogen production system, eliminates the space waste caused by the separate arrangement of the light fermentation reaction zone 12 and the dark fermentation reaction zone 11, and at the same time eliminates the separate arrangement of the light fermentation reaction zone 12 and the dark fermentation reaction zone 11, and the connecting pipes that need to be arranged between the light fermentation reaction zone 12 and the dark fermentation reaction zone 11 are simplified. The structure of the dark-light two-stage hydrogen production system is reduced, and the investment and operation costs of the dark-light two-stage hydrogen production system are reduced. In short, the photofermentation reaction zone 12 and the dark fermentation reaction zone 11 are integrated to realize the continuous treatment of organic wastewater and hydrogen production in the dark-light two-stage integrated manner, which is beneficial to reduce the footprint of the dark-photofermentation hydrogen production system, reduce the economic and energy consumption costs of reactor construction and operation, improve wastewater treatment and hydrogen production performance, and improve the economy of the dark-photofermentation hydrogen production system.

[0044] Specifically, the dark fermentation reaction area 11 and the light fermentation reaction area 12 can be arranged side by side, for example, arranged in sequence from top to bottom, from left to right, from front to back, etc. They can also be arranged in sequence from inside to outside, for example, Figure 1As shown, a dark fermentation reaction zone 11 and a light fermentation reaction zone 12 are arranged in sequence from the inside to the outside. The water inlet of the dark fermentation reaction zone 11 can be located at the top or side of the dark fermentation reaction zone 11, and the water inlet of the dark fermentation reaction zone 11 is connected with the outside through a water inlet pipe 13. The water outlet of the dark fermentation reaction zone is located at the bottom of the dark fermentation reaction zone 11, and the water inlet of the light fermentation reaction zone 12 is arranged at the bottom of the light fermentation reaction zone 12. The water outlet of the dark fermentation reaction zone is connected with the water inlet of the light fermentation reaction zone 12, and the water outlet 15 of the light fermentation reaction zone is located at the upper part of the light fermentation reaction zone 12.

[0045] Alternatively, the light fermentation reaction zone 12 can be set inside, and the dark fermentation reaction zone 11 can be set outside the light fermentation reaction zone 12. In this case, the water inlet of the dark fermentation reaction zone 11 can be set at the top or side of the dark fermentation reaction zone 11; the water outlet of the dark fermentation reaction zone is set at the bottom of the dark fermentation reaction zone 11, the water inlet of the light fermentation reaction zone 12 is set at the bottom of the light fermentation reaction zone 12, and the water outlet 15 of the light fermentation reaction zone is set at the upper part of the light fermentation reaction zone 12.

[0046] When the water inlet of the dark fermentation reaction zone 11 is set at the top or the side, the water inlet of the dark fermentation reaction zone 11 should be set to avoid the gas outlet 19 to ensure that the water inlet of the dark fermentation reaction zone 11 can smoothly input wastewater, and the gas outlet 19 can smoothly discharge the gases such as hydrogen produced by the dark fermentation reaction and the light fermentation reaction. Moreover, it should be noted that no matter how the dark fermentation reaction zone 11 and the light fermentation reaction zone 12 are arranged as one (that is, the water outlet 15 of the dark fermentation reaction zone and the water inlet of the light fermentation reaction zone 12 are not connected by an additional pipe), the water inlet, water outlet and air outlet of the dark fermentation reaction zone 11 and the light fermentation reaction zone 12 should all function normally to ensure that the microbial reaction in the dark fermentation reaction zone 11 and the light fermentation reaction zone 12 can proceed smoothly and as fully as possible; at the same time, it is necessary to ensure that the space in the dark fermentation reaction zone 11 and the light fermentation reaction zone 12 can be fully utilized as much as possible to ensure that the water discharged from the water outlet 15 of the light fermentation reaction zone is fully reacted and treated water.

[0047] In addition, the dark-light two-stage hydrogen production system in the present invention also includes an illumination component 3 for providing the required light for the light fermentation reaction zone 12, and the illumination component 3 is arranged to avoid the dark fermentation reaction zone 11; the light released by the illumination component 3 promotes the effective hydrogen production metabolism of the light fermentation reaction, thereby improving the hydrogen production efficiency in the light fermentation reaction zone 12; the illumination component 3 and the dark fermentation reaction zone 11 are arranged to avoid each other, which means that the light released by the illumination component 3 will not destroy the environment of the dark fermentation reaction in the dark fermentation reaction zone 11, nor will it inhibit the dark fermentation reaction.

[0048] When the photofermentation reaction zone 12 is able to receive sufficient sunlight, the illumination component 3 can specifically be sunlight, and it should be noted that when sunlight is used as the illumination component 3, the photofermentation reaction zone 12 must be able to receive light evenly to ensure that the photofermentation reaction zone 12 has a high hydrogen production efficiency; this reduces the use of illumination equipment such as incandescent lamps, and reduces the manufacturing and operating costs of the dark-light two-stage hydrogen production system.

[0049] And / or, a photosensitive material (such as titanium oxide, cadmium sulfide, ferrous sulfide, etc.) is provided in the photofermentation reaction zone 12 to enhance the light energy capture capability and hydrogen production efficiency of the photofermentation reaction process.

[0050] like Figure 1 As shown, the dark fermentation reaction zone 11 and the light fermentation reaction zone 12 constitute a dark-light integrated reactor 1. When the dark fermentation reaction zone 11 and the light fermentation reaction zone 12 are arranged sequentially from the inside to the outside, the dark fermentation reaction zone 11 can be a hollow cylinder, a cylinder or a polygonal prism; the light fermentation reaction zone 12 can be a ring-shaped hollow cylinder with the dark fermentation reaction zone 11 nested in the middle. The illumination component 3 can be a plurality of light sources arranged outside the light fermentation reaction zone 12 and arranged toward the light fermentation reaction zone 12. The light source is arranged on the light source adjustment bracket. By arranging a corresponding driving device on the light source adjustment bracket, the distance between the light source and the light fermentation reaction zone 12 can be adjusted, thereby adjusting the light intensity received by the light fermentation reaction zone 12. At this time, the light fermentation reaction zone 12 is made of a light-transmitting material, such as organic glass, a light-transmitting polymer, or other light-transmitting glass or other structures. The dark fermentation reaction zone 11 is made of an opaque material to prevent the light emitted by the light source from entering the dark fermentation reaction zone 11 and destroying the normal progress of the dark fermentation reaction.

[0051] In addition, a corresponding support and a driving device may be provided under the light source adjustment bracket, and the driving device may be used to drive the light source adjustment bracket to rotate, so that each area of ​​the photofermentation reaction zone 12 can receive uniform illumination, ensuring balanced reaction in the photofermentation reaction zone 12. The light source may specifically be a tungsten filament lamp, an incandescent lamp, or an LED lamp, etc., which are suitable for capturing and utilizing microorganisms in the photofermentation reaction zone 12; the driving device may also not be provided, and the light source adjustment bracket may be arranged around the reactor, so that each area of ​​the photofermentation reaction zone 12 receives light uniformly; the light source adjustment bracket may also be provided with a corresponding control device and a driving component capable of adjusting the light source height, illumination frequency, etc., so that light source parameters related to the metabolism of photofermentation hydrogen-producing microorganisms, such as light intensity and light cycle, are adjusted to promote the effective conduct of photofermentation hydrogen-producing metabolism.

[0052] The light source can also be placed deep inside the photofermentation reaction zone 12, so that the light emitted from all directions of the light source can be used by the microorganisms in the photofermentation reaction zone 12, thereby further improving the hydrogen production efficiency in the photofermentation reaction zone 12. Since the light source is in direct contact with the microorganisms in the photofermentation reaction zone 12, it is necessary to avoid the heat generated by the light source from burning and killing the microorganisms in the photofermentation reaction zone 12. The light intensity of the light source can be adjusted, or a heat-insulating but light-transmitting protective cover can be set on the outer surface of the light source to avoid the mass death of the microorganisms in the photofermentation reaction zone 12.

[0053] When the light fermentation reaction zone 12 and the dark fermentation reaction zone 11 are arranged in sequence from the inside to the outside, the light fermentation reaction zone 12 can be an annular cylinder. At this time, the light source can be arranged in the middle of the light fermentation reaction zone 12 (outside the light fermentation reaction zone 12), and the side of the light fermentation reaction zone 12 facing the light source needs to adopt light-transmitting material to ensure that the light generated by the light source can smoothly enter the light fermentation reaction zone 12, and a light-shielding shell needs to be set between the light fermentation reaction zone 12 and the dark fermentation reaction zone 11 to prevent the light emitted by the light source from destroying the dark fermentation reaction environment of the dark fermentation reaction zone 11. Moreover, when the light fermentation reaction zone 12 and the dark fermentation reaction zone 11 are arranged in sequence from the inside to the outside, the light fermentation reaction zone 12 can also be a cylinder. At this time, the light source can be directly extended into the light fermentation reaction zone 12. At this time, a light shielding shell needs to be arranged between the light fermentation reaction zone 12 and the dark fermentation reaction zone 11 to prevent the light emitted by the light source from destroying the dark fermentation reaction environment of the dark fermentation reaction zone 11; at the same time, attention should be paid to the problem of direct contact between the light source and the microorganisms in the light fermentation reaction zone 12, which leads to the death of a large number of microorganisms. The specific protective measures can be referred to the above content, which will not be repeated here.

[0054] In the present invention, a first carrier filler 14 for the attachment of microorganisms in the dark fermentation reaction zone 11 is provided in the dark fermentation reaction zone 11. The first carrier filler 14 can specifically be a sewage biological carrier filler such as a porous polyethylene ring, biofilm-bearing carbon fiber, sponge, nylon rope, etc. If the first carrier filler 14 is not provided in the dark fermentation reaction zone 11, the microorganisms in the dark fermentation reaction zone 11 will be in a suspended state. After the first carrier filler 14 is provided in the dark fermentation reaction zone 11, the microorganisms will be able to attach to the first carrier filler 14, thereby increasing the number and concentration of microorganisms in the dark fermentation reaction zone 11 and promoting the rate of dark fermentation hydrolysis acid production and hydrogen production metabolism.

[0055] In addition, the microorganisms inoculated in the dark fermentation reaction zone 11 include anaerobic fermentation granular sludge or flocculent sludge that has been pretreated by heating, acid-base pretreatment, or ultrasound or microwave pretreatment, and can also be inoculated with dark fermentation hydrolysis acid-producing biofilms that have been pre-cultured in other acid-producing reactors, as long as the microorganisms inoculated in the dark fermentation reaction zone 11 can successfully complete the dark fermentation reaction. At the same time, iron-based or carbon-based materials such as magnetite, activated carbon, and biochar can also be added to the dark fermentation reaction zone 11 to enhance the rate of dark fermentation hydrogen production; and regulate the rate at which dark fermentation metabolism produces organic acid products (such as acetic acid and butyric acid, etc.) that are more easily utilized by light fermentation reactant microorganisms, and promote the hydrogen production efficiency of the light fermentation reaction. However, it should be noted that the concentration of the organic acid product should not be too high, so as to avoid the concentration of the organic acid product being too high and inhibiting the hydrogen production efficiency of the light fermentation reaction.

[0056] And / or, a second carrier filler is provided in the photofermentation reaction zone 12 for the attachment of microorganisms in the photofermentation reaction zone 12. The second carrier filler helps the aggregation of photofermentation reaction microorganisms to form biofilms or photofermentation microorganism particles, thereby increasing the microorganism content in the photofermentation reaction zone 12 and improving the hydrogen production efficiency of the photofermentation reaction zone 12. Figure 1 As shown, in the present invention, the bottom of the photofermentation reaction zone 12 is further provided with a bacterial cell collection port 17 for collecting excess photosynthetic bacterial cells in the photofermentation reaction zone 12 .

[0057] The present invention provides a second three-phase separator 16 in the photo-fermentation reaction zone 12, and the second three-phase separator 16 is arranged below the water outlet 15 of the photo-fermentation reaction zone. Figure 1 As shown, the second three-phase separator 16 includes an expanded diameter section arranged at the upper part of the photo-fermentation reaction zone 12, the cross-sectional area of ​​the upper part of the expanded diameter section is larger than the cross-sectional area of ​​the lower part of the expanded diameter section, and a baffle corresponding to the expanded diameter section is provided in the upper part of the photo-fermentation reaction zone 12, the baffle is frustum-shaped, and there is a gap between the end of the baffle away from the top of the photo-fermentation reaction zone 12 and the expanded diameter section, wherein the slope of the expanded diameter section, i.e., the sedimentation zone, is 45°-80°, which is more conducive to the bacteria flowing upward with the gas phase and the liquid phase in the photo-fermentation reaction zone 12 to sink here and flow back into the photo-fermentation reaction zone 12. The second three-phase separator 16 is used to separate the photo-fermentation bacteria, water phase and gas products in the photo-fermentation reaction zone 12. As the liquid level in the photo-fermentation reaction zone 12 rises, the three-phase mixture formed by the photo-fermentation bacteria, water phase and gas products continues to rise. After the three-phase mixture rises to the expanded diameter section, the photo-fermentation bacteria settle downward first due to their greater weight, while the lighter water phase and gas products continue to rise. After the water-gas two-phase mixture rises to the water outlet 15 of the photo-fermentation reaction zone, the water phase enters the first three-phase separator 2 from the water outlet 15 of the photo-fermentation reaction zone for secondary three-phase separation, and the gas continues to rise until it is discharged from the gas outlet 19.

[0058] The first three-phase separator 2 includes a water inlet 21 of the first three-phase separator, a water outlet 22 of the first three-phase separator, a gas outlet 23 of the first three-phase separator, and a bacterial cell collection port 24 of the first three-phase separator. The water outlet 15 of the photofermentation reaction zone is connected to the water inlet 21 of the first three-phase separator, so as to prevent the gas in the photofermentation reaction zone 12 from leaking from the water outlet 15 of the photofermentation reaction zone, thereby avoiding the occurrence of safety accidents.

[0059] like Figure 1 As shown, during operation, the organic wastewater first enters the dark fermentation reaction zone 11 through the feed port, adopts a downflow water inlet, passes through the first carrier filler 14 in the dark fermentation reaction zone 11, completes dark fermentation acid and hydrogen production, and then the dark fermentation substrate is evenly distributed through the water distributor 18 into the light fermentation reaction zone 12, and after the photosynthetic bacteria use organic acid to produce hydrogen, it enters the first three-phase separator 2 through the water outlet 15 of the light fermentation reaction zone and the water inlet 21 of the first three-phase separator connected thereto, and finally flows out of the dark-light two-stage hydrogen production system through the water outlet 22 of the first three-phase separator, realizing continuous and efficient treatment and hydrogen production of organic wastewater. The hydrogen produced by the dark fermentation reaction zone 11 and the light fermentation reaction zone 12 is discharged from the reaction system through a common gas outlet.

[0060] Although there are multiple technical solutions in the claims and the specification of the present invention, there is no situation in which contrary technical inspiration is given.

[0061] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A dark-light two-stage hydrogen production system for treating organic wastewater, It is characterized in that It comprises a dark fermentation reaction zone, a light fermentation reaction zone and a pretreatment zone, wherein the water inlet of the dark fermentation reaction zone is used to input wastewater to be treated, and the water outlet of the dark fermentation reaction zone is connected with the water inlet of the light fermentation reaction zone through the pretreatment zone; The pretreatment zone is provided with a water distributor, a pH adjustment unit and an ammonia nitrogen treatment unit, which are used to adjust the organic acid concentration, pH and ammonia nitrogen concentration of the product of the dark fermentation reaction zone to reduce the inhibitory effect of the product of the dark fermentation reaction zone on the growth and metabolism of microorganisms in the light fermentation reaction zone. The water outlet of the dark fermentation reaction zone is connected to the water inlet of the light fermentation reaction zone through the water distributor; The water outlet of the light fermentation reaction zone is connected to the water inlet of the first three-phase separator, and the top of the dark fermentation reaction zone and the top of the light fermentation reaction zone are provided with a common gas outlet; the common gas outlet is connected to the gas outlet of the first three-phase separator; The light fermentation reaction zone and the dark fermentation reaction zone are arranged integrally, and the dark fermentation reaction zone and the light fermentation reaction zone are arranged in sequence from the inside to the outside, the water inlet of the dark fermentation reaction zone is arranged at the top or side of the dark fermentation reaction zone, the water outlet of the dark fermentation reaction zone is arranged at the bottom of the dark fermentation reaction zone, the water inlet of the light fermentation reaction zone is arranged at the bottom of the light fermentation reaction zone, and the water outlet of the light fermentation reaction zone is arranged at the upper part of the light fermentation reaction zone; The volume ratio of the light fermentation reaction zone to the dark fermentation reaction zone is 3-10; The dark fermentation reaction zone is provided with a first carrier filler for the attachment of microorganisms in the dark fermentation reaction zone, and the dark fermentation reaction zone is also provided with magnetite, activated carbon or biochar; The photo-fermentation reaction zone is provided with a second carrier filler for the attachment of microorganisms in the photo-fermentation reaction zone, and the bottom of the photo-fermentation reaction zone is also provided with a bacterial cell collection port for collecting excess photosynthetic bacterial cells in the photo-fermentation reaction zone; A second three-phase separator is provided in the photo-fermentation reaction zone, and the second three-phase separator is arranged below the water outlet of the photo-fermentation reaction zone; The dark-light two-stage hydrogen production system also includes an illumination component for providing the required illumination for the light fermentation reaction zone, and the illumination component is arranged to avoid the dark fermentation reaction zone; the illumination component is a plurality of light sources arranged outside the light fermentation reaction zone and facing the light fermentation reaction zone, and the plurality of light sources are arranged on a light source adjustment bracket, and a corresponding driving device is arranged on the light source adjustment bracket to adjust the distance between the light source and the light fermentation reaction zone; a corresponding support and a driving device are arranged below the light source adjustment bracket, and the light source adjustment bracket is driven to rotate by the driving device; a photosensitive material is arranged in the light fermentation reaction zone.

2. The dark-light two-stage hydrogen production system according to claim 1, It is characterized in that The second three-phase separator includes an expanded diameter section arranged at the upper part of the photo-fermentation reaction zone, the cross-sectional area of ​​the upper part of the expanded diameter section is larger than the cross-sectional area of ​​the lower part of the expanded diameter section, and a baffle corresponding to the expanded diameter section is provided in the upper part of the photo-fermentation reaction zone, and the baffle is frustum-shaped, and there is a gap between the end of the baffle away from the top of the photo-fermentation reaction zone and the expanded diameter section, and the slope of the expanded diameter section is 45°-80°.

3. The dark-light two-stage hydrogen production system according to claim 1, It is characterized in that The first carrier filler is one or more of porous polyethylene rings, biofilm-bearing carbon fibers, sponges and nylon ropes.

4. The dark-light two-stage hydrogen production system according to claim 1, It is characterized in that The photosensitive material is titanium oxide or cadmium sulfide.

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