A fluidized bed multi-stage anaerobic process for synergistic wastewater treatment and energy recovery system

Abstract

This invention provides a fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system, belonging to the field of wastewater treatment and energy recovery. The system includes a pretreatment module for synergistic wastewater treatment via ultrasonic crushing and enzymatic hydrolysis, a dark fermentation module, an anaerobic digestion module, a microbial fuel cell module, a gas collection module for collecting gases generated by each module, an electrical energy regulation module for applying electrical energy generated by the microbial fuel cell to the dark fermentation and anaerobic digestion modules to form a non-uniform potential field, and a comprehensive regulation module for receiving detection signals and regulating the gas supply. The discharge end of the dark fermentation module is connected to the feed ends of both the anaerobic digestion and microbial fuel cell modules, forming two series paths: dark fermentation-anaerobic digestion-microbial fuel cell and dark fermentation-microbial fuel cell-anaerobic digestion. This invention achieves deep purification of wastewater and synergistic recovery of multiple forms of energy, including hydrogen, methane, and electricity.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment and energy recovery technology, and in particular to a fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system. Background Technology

[0002] With the acceleration of industrialization and urbanization, the treatment and resource utilization of high-concentration organic wastewater has become a key challenge in the fields of environmental protection and sustainable development. Traditional wastewater treatment technologies are energy-intensive and fail to fully recover the chemical energy contained in wastewater, resulting in energy waste. Therefore, anaerobic biological technologies that combine wastewater treatment with energy recovery, based on the concept of turning waste into treasure, have received widespread attention and become the main development trend in this field.

[0003] Currently, anaerobic digestion, dark fermentation, and microbial fuel cells are three mainstream energy-recovery-oriented anaerobic wastewater treatment technologies. Among them, anaerobic digestion is the most mature and widely used, converting organic matter into methane biogas; dark fermentation utilizes hydrogen-producing bacteria to convert carbohydrates into hydrogen; and microbial fuel cells, as an emerging technology, can directly convert the chemical energy of organic matter into electrical energy. However, single anaerobic processes have functional limitations: dark fermentation results in incomplete substrate conversion, anaerobic digestion decomposes organic matter slowly, and the effluent contains residual COD (especially volatile fatty acids), nitrogen, and phosphorus. Furthermore, microbial fuel cells struggle to treat high-load wastewater. To overcome the bottlenecks of single technologies, coupling dark fermentation with microbial fuel cells and anaerobic digestion, utilizing the volatile fatty acids produced by dark fermentation as high-quality substrates for subsequent processes, and achieving cascade utilization of organic matter and energy recovery, has become an important research direction in recent years.

[0004] Although existing technologies recognize the advantages of multi-process coupling in concept, in practice, due to the fragmentation of system structure, the limitations of reactor form and the incompleteness of energy recovery path, there are significant deficiencies in total energy conversion efficiency, pollutant removal depth, system operation stability and engineering scalability. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, the purpose of this invention is to provide a fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system, which realizes the deep purification of wastewater, the cascade conversion and recovery of organic chemical energy into hydrogen energy, methane and electrical energy, and the degradation of organic matter and removal of nitrogen and phosphorus through multi-stage synergistic treatment, ensuring stable effluent compliance while improving energy conversion efficiency and system operation stability.

[0006] To achieve the above objectives, the present invention provides a fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system, including a pretreatment module, a dark fermentation module, an anaerobic digestion module, a microbial fuel cell module, a gas collection module, an electrical energy regulation module, and a comprehensive regulation module; The pretreatment module is connected to the feed end of the dark fermentation module, and the discharge end of the dark fermentation module is connected to the feed end of the anaerobic digestion module and the feed end of the microbial fuel cell module, forming a first series path of dark fermentation-anaerobic digestion-microbial fuel cell and a second series path of dark fermentation-microbial fuel cell-anaerobic digestion. The gas collection module is connected to the gas collection ends of the dark fermentation module, the anaerobic digestion module, and the microbial fuel cell module, respectively, and is used to collect the gas generated by each module. The power regulation module is electrically connected to the power generation end of the microbial fuel cell module, and the power regulation module is also electrically connected to the electrode components in the dark fermentation module and the anaerobic digestion module, for applying the power generated by the microbial fuel cell module to the dark fermentation module and the anaerobic digestion module. The integrated control module is connected to the signal detection terminals and gas pipelines of the gas collection module, the microbial fuel cell module, the anaerobic digestion module, and the dark fermentation module, respectively, and is used to receive detection signals and regulate the gas supply of each module.

[0007] Compared with the prior art, the present invention discloses at least the following technical effects: (1) This invention realizes the cascade utilization of the chemical energy of organic matter in wastewater through a dual-path multi-stage anaerobic process series structure. Combined with the energy internal circulation mechanism of the microbial fuel cell power generation feedback dark fermentation module and anaerobic digestion module to form a non-uniform potential field, it solves the problems of single anaerobic process energy recovery form and low cascade conversion efficiency of traditional coupled process. It successfully realizes the synergistic recovery of multiple forms of energy such as hydrogen, methane and electricity, and greatly improves the total energy conversion efficiency of the system. At the same time, the two differentiated series paths can focus on total energy recovery and high-grade electricity recovery respectively, effectively adapting to the energy utilization needs of different scenarios, thereby ensuring the flexible application of the technology.

[0008] (2) The present invention adopts a pretreatment method of ultrasonic crushing and biological enzymatic hydrolysis, combined with a multi-stage degradation process of dark fermentation, anaerobic digestion and microbial fuel cell, which solves the problems of incomplete substrate conversion and slow decomposition of difficult-to-degrade organic matter in the existing technology. It not only achieves the deep degradation of complex organic matter in wastewater, but also simultaneously completes the efficient removal of nitrogen and phosphorus, solves the technical problems of residual COD, nitrogen and phosphorus in the effluent of traditional anaerobic process, realizes the deep purification treatment of wastewater, and ensures that the effluent indicators stably meet the discharge standards.

[0009] (3) The present invention constructs an internal closed-loop circulation system of matter and energy, and uses carbon dioxide for internal circulation of gas produced by dark fermentation and gas produced by microbial fuel cell reaction. Combined with the energy reuse mode of electric energy feedback, the external energy consumption and material consumption of the system are greatly reduced. At the same time, the system provided by the present invention also effectively improves the internal mass transfer efficiency of the system, solves the problems of structural fragmentation and poor operation stability of traditional coupled process, significantly enhances the operation stability and engineering scalability of the system, and is more suitable for industrial-scale application needs. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of a fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of a fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system provided in Embodiment 2 of the present invention; Explanation of reference numerals in the attached figures: Figure 1Components: 1. First storage tank; 2. Ultrasonic crusher; 3. First electric valve; 4. First peristaltic pump; 5. Second storage tank; 6. Cellulose-degrading enzyme; 7. Second electric valve; 8. Second peristaltic pump; 9. Third electric valve; 10. Dark fermentation feed end; 11. First liquid distributor; 12. Dark fermentation discharge end; 13. Fourth electric valve; 14. Third storage tank; 15. Dark fermentation circulating discharge end; 16. Fifth electric valve; 17. Third peristaltic pump; 18. First liquid flow meter; 19. Dark fermentation circulating feed end; 20. Hydrogen production lower liquid chamber; 21. PA6 carrier particles; 22. Hydrogen production reaction chamber; 23. First gas collection end. ; 24. Second gas collection end; 25. First electric gas valve; 26. First gas collection bag; 27. Sixth electric valve; 28. Fourth peristaltic pump; 29. ​​Seventh electric valve; 30. Anaerobic digestion feed end; 31. Second liquid distributor; 32. Anaerobic digestion discharge end; 33. Eighth electric valve; 34. Fourth storage tank; 35. Anaerobic digestion circulation discharge end; 36. Ninth electric valve; 37. Fifth peristaltic pump; 38. Second liquid flow meter; 39. Anaerobic digestion circulation feed end; 40. Methanogenic lower liquid chamber; 41. Coconut shell activated carbon granules; 42. Methanogenic reaction chamber; 43. Third gas collection end; 44. Fourth gas collection end; 45. 46. ​​Second electric gas valve; 47. Tenth electric valve; 48. Sixth peristaltic pump; 49. Eleventh electric valve; 50. Feed end of microbial fuel cell; 51. Anode chamber; 52. Anode; 53. Outlet end of microbial fuel cell; 54. Twelfth electric valve; 55. Fifth storage tank; 56. Third electric valve; 57. Gas rotor flow meter; 58. Electricity-generating liquid chamber; 59. Nano gas disc; 60. Third liquid distributor; 61. Coconut shell activated carbon particles; 62. Fifth gas collection end; 63. Sixth gas collection end; 64. Fourth electric valve; 65. Carbon dioxide outlet end; 66. Microalgae; 67. Cathode; 68. Cathode chamber; 69. Proton exchange membrane; 70. Supercapacitor; 71. Multimeter; 72. Computer; 73. Fifth electric air valve; 74. Sixth electric air valve; 75. Seventh electric air valve; 76. Integrated signal processor; 77. COD detection outlet; 78. Carbon dioxide inlet; 79. Third gas collection bag; 80. First DC-DC converter; 81. Second DC-DC converter; 82. Third DC-DC converter; 83. First carbon felt electrode; 84. Fourth DC-DC converter; 85. Fifth DC-DC converter; 86. Sixth DC-DC converter; 87. Second carbon felt electrode.

[0012] Figure 2Components: 1. First storage tank; 2. Ultrasonic crusher; 3. First electric valve; 4. First peristaltic pump; 5. Second storage tank; 6. Cellulose-degrading enzyme; 7. Second electric valve; 8. Second peristaltic pump; 9. Third electric valve; 10. Dark fermentation feed end; 11. First liquid distributor; 12. Dark fermentation discharge end; 13. Fourth electric valve; 14. Third storage tank; 15. Dark fermentation circulating discharge end; 16. Fifth electric valve; 17. Third peristaltic pump; 18. First liquid flow meter; 19. Dark fermentation circulating feed end; 20. Hydrogen production lower liquid chamber; 21. PA6 carrier particles; 22. Hydrogen production reaction chamber; 23. First gas collection end. 24. Second gas collection end; 25. First electric gas valve; 26. First gas collection bag; 27. Sixth electric valve; 28. Fourth peristaltic pump; 29. ​​Seventh electric valve; 30. Microbial fuel cell feed end; 31. Anode chamber; 32. Anode; 33. Microbial fuel cell outlet end; 34. Eighth electric valve; 35. Fourth storage tank; 36. Second electric valve; 37. Gas rotor flow meter; 38. Electricity generation liquid chamber; 39. Nano gas disc; 40. Second liquid distributor; 41. Coconut shell activated carbon particles; 42. Third gas collection end; 43. Fourth gas collection end; 44. Third electric valve; 45. Carbon dioxide outlet end; 6. Microalgae; 47. Cathode; 48. Cathode chamber; 49. Proton exchange membrane; 50. Supercapacitor; 51. Multimeter; 52. Computer; 53. Ninth electric valve; 54. Fifth peristaltic pump; 55. Tenth electric valve; 56. Anaerobic digestion feed end; 57. Third liquid distributor; 58. Anaerobic digestion discharge end; 59. Eleventh electric valve; 60. Fifth storage tank; 61. Anaerobic digestion circulation discharge end; 62. Twelfth electric valve; 63. Sixth peristaltic pump; 64. Third liquid flow meter; 65. Anaerobic digestion circulation feed end; 66. Methanogenic lower chamber; 67. Coconut shell activated carbon granules; 68. Methanogenic reaction chamber 69. Fifth gas collection end; 70. Sixth gas collection end; 71. Fourth electric gas valve; 72. Second gas collection bag; 73. Fifth electric gas valve; 74. Sixth electric gas valve; 75. Seventh electric gas valve; 76. Integrated signal processor; 77. COD detection outlet; 78. Carbon dioxide inlet; 79. Third gas collection bag; 80. First DC-DC converter; 81. Second DC-DC converter; 82. Third DC-DC converter; 83. Fourth DC-DC converter; 84. Fifth DC-DC converter; 85. Sixth DC-DC converter; 86. First carbon felt electrode; 87. Second carbon felt electrode. Detailed Implementation

[0013] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] This invention provides a fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system, including a pretreatment module for synergistic pretreatment of wastewater by ultrasonic crushing and biological enzymatic hydrolysis, a dark fermentation module for realizing hydrogen production from organic matter in wastewater, an anaerobic digestion module for realizing methane production from organic matter in wastewater, a microbial fuel cell module for realizing chemical energy-to-electricity conversion from organic matter in wastewater, a gas collection module for realizing gas classification, collection and temporary storage, an electrical energy regulation module for realizing electrical energy regulation, transmission and feedback, and a comprehensive regulation module for realizing system signal detection and intelligent regulation of gas supply; The pretreatment module is connected to the feed end of the dark fermentation module, and the discharge end of the dark fermentation module is connected to the feed end of the anaerobic digestion module and the feed end of the microbial fuel cell module, forming a first series path of dark fermentation-anaerobic digestion-microbial fuel cell with hydrogen energy-methane energy-electric energy as the recovery gradient, and a second series path of dark fermentation-microbial fuel cell-anaerobic digestion with hydrogen energy-electric energy-methane energy as the recovery gradient. The gas collection module is connected to the gas collection ends of the dark fermentation module, anaerobic digestion module, and microbial fuel cell module, respectively, and is used to collect gases such as hydrogen and methane produced by the reactions of each module. The power regulation module is electrically connected to the power generation end of the microbial fuel cell module, and is also electrically connected to the electrode components in the dark fermentation module and the anaerobic digestion module. It is used to apply the power generated by the microbial fuel cell module to the dark fermentation module and the anaerobic digestion module in a directional manner to enhance their anaerobic reaction. The integrated control module is connected to the signal detection terminals and gas pipelines of the gas collection module, microbial fuel cell module, anaerobic digestion module, and dark fermentation module, respectively, and is used to receive the reaction status detection signals of each module and adjust the gas supply and supply rate of each module as needed.

[0016] The above content will be further described below using specific embodiments. The embodiments provided are only some embodiments of the present invention.

[0017] Example 1 Based on the above, during the dark fermentation process, the chemical energy of organic matter in the wastewater, such as carbohydrates, some proteins, and lipids, is recovered in the form of hydrogen. The fermentation effluent contains a large amount of undecomposed substrates and byproducts such as acetic acid, butyric acid, and alcohols. These effluents, rich in volatile fatty acids, can be treated through a first series path (dark fermentation - anaerobic digestion - microbial fuel cell). First, through anaerobic digestion, most of the volatile fatty acids and some recalcitrant substrates are recovered as energy, primarily in the form of methane. The low organic load effluent after anaerobic digestion is more suitable for tail-end treatment using a microbial fuel cell, achieving the treatment of residual volatile fatty acids in the wastewater and reducing nitrogen and phosphorus levels. Therefore, the system provided in this embodiment is implemented using the first series path, such as... Figure 1 As shown, the system includes: The pretreatment module includes a first storage tank 1 and a second storage tank 5 connected in sequence by pipelines. The first storage tank 1 is connected to an ultrasonic crusher 2 for ultrasonically crushing the raw wastewater and breaking down complex organic matter. The connecting pipeline between the first storage tank 1 and the second storage tank 5 is sequentially equipped with a first electric valve 3 for switching the wastewater conveying pipeline on and off and a first peristaltic pump 4 for quantitatively conveying wastewater. The second storage tank 5 contains a cellulase 6 for biologically enzymatically hydrolyzing the ultrasonically crushed wastewater and degrading cellulose organic matter.

[0018] The dark fermentation module includes a hydrogen production submersible chamber 20, a first liquid distributor 11 for uniform water distribution, and a hydrogen production reaction chamber 22. A second storage tank 5 is connected to the dark fermentation feed end 10 on one side of the hydrogen production submersible chamber 20 via a pipeline equipped with a second electric valve 7. This pipeline is also equipped with a second peristaltic pump 8 for quantitative wastewater transport and a third electric valve 9 for auxiliary pipeline switching. The third electric valve 9 is located near the dark fermentation feed end 10. The second peristaltic pump 8 is positioned between the second electric valve 7 and the third electric valve 9, with the second electric valve 7 located near the second storage tank 5. The hydrogen production submersible chamber 20 is connected to the hydrogen production reaction chamber 22 via the first liquid distributor 11. The hydrogen production reaction chamber 22 is filled with PA6 carrier particles 21 dispersed in the liquid environment for attaching hydrogen-producing microbial films. A dark fermentation circulation discharge end 15 is located at the bottom of the upper end of the hydrogen production reaction chamber 22. The feed end 15 is connected to the dark fermentation circulation feed end 19 via a pipeline equipped with a fifth electric valve 16. A third peristaltic pump 17 for driving the internal circulation of wastewater and a first liquid flow meter 18 for measuring the volume of circulating wastewater are also connected in series on the connecting pipeline. The third peristaltic pump 17 is located near the dark fermentation circulation discharge end 15, and the first liquid flow meter 18 is located near the dark fermentation circulation feed end 19. The upper top of the hydrogen production reaction chamber 22 is provided with a first gas collecting end 23 and a second gas collecting end 24 for collecting hydrogen production reaction gases. The first gas collecting end 23 and the second gas collecting end 24 are connected to the first gas collecting bag 26 of the gas collecting module via a pipeline equipped with a first electric valve 25 for opening and closing the gas path. The upper side of the hydrogen production reaction chamber 22 is provided with a dark fermentation discharge end 12. The dark fermentation discharge end 12 is connected to the third storage tank 14 via a pipeline equipped with a fourth electric valve 13 for opening and closing the water outlet pipeline.

[0019] The anaerobic digestion module includes a methanogenic lower liquid chamber 40, a second liquid distributor 31 for uniform water distribution, and a methanogenic reaction chamber 42. A third storage tank 14 is connected to the anaerobic digestion feed end 30 on one side of the methanogenic lower liquid chamber 40 via a pipeline equipped with a seventh electric valve 29. This connecting pipeline is also equipped with a sixth electric valve 27 for opening and closing the pipeline and a fourth peristaltic pump 28 for quantitative wastewater transport. The sixth electric valve 27 is located near the third storage tank 14, and the fourth peristaltic pump 28 is located between the sixth electric valve 27 and the seventh electric valve 29. The seventh electric valve 29 is located near the anaerobic digestion feed end 30. The methanogenic lower liquid chamber 40 is connected to the methanogenic reaction chamber 42 via the second liquid distributor 31. The methanogenic reaction chamber 42 is filled with coconut shell activated carbon particles 41 dispersed in the liquid phase environment for attaching methanogenic microbial films. An anaerobic digestion circulation discharge end 35 is located at the bottom of the upper end of the methanogenic reaction chamber 42. The anaerobic digestion cycle discharge end 35 is connected to the anaerobic digestion cycle feed end 39 via a pipeline equipped with a ninth electric valve 36. A fifth peristaltic pump 37 for driving the internal circulation of wastewater and a second liquid flow meter 38 for measuring the volume of circulating wastewater are also connected in series on this connecting pipeline. The fifth peristaltic pump 37 is positioned near the anaerobic digestion cycle discharge end 35, and the second liquid flow meter 38 is positioned near the anaerobic digestion cycle feed end 39. The upper top of the methanogenic reaction chamber 42 is equipped with a third gas collection end 43 and a fourth gas collection end 44 for collecting methanogenic reaction gases. The third gas collection end 43 and the fourth gas collection end 44 are connected to the second gas collection bag 46 of the gas collection module via a pipeline equipped with a second electric valve 45 for opening and closing the gas path. The upper side of the methanogenic reaction chamber 42 is equipped with an anaerobic digestion discharge end 32, which is connected to the fourth storage tank 34 via a pipeline equipped with an eighth electric valve 33 for opening and closing the effluent pipeline.

[0020] The microbial fuel cell module includes a liquid-generating chamber 58, a third liquid distributor 60 for uniform water distribution, an anode chamber 51, and a cathode chamber 68. A fourth storage tank 34 is connected to the microbial fuel cell feed end 50 of the liquid-generating chamber 58 via a pipeline equipped with a tenth electric valve 47. This pipeline is also equipped with a sixth peristaltic pump 48 for quantitative wastewater transport and an eleventh electric valve 49 for auxiliary pipeline connection / disconnection. The eleventh electric valve 49 is located near the microbial fuel cell feed end 50. The sixth peristaltic pump 48 is located between the tenth and eleventh electric valves, with the tenth electric valve 47 located near the fourth storage tank 34. The liquid-generating chamber 58 is connected to the anode chamber 51 via the third liquid distributor 60. The anode chamber 51 is filled with coconut shell activated carbon particles 61 dispersed in the liquid environment for attaching the electrogenic microbial membrane. A proton exchange membrane 69 for proton conduction is located on the side of the anode chamber 51, with the other side of the proton exchange membrane 69 contacting the cathode chamber 68. The cathode chamber 68 contains… The anode chamber 51 is filled with microalgae 66 for photosynthesis using carbon dioxide. The top of the anode chamber 51 is equipped with a fifth gas collecting end 62 and a sixth gas collecting end 63 for collecting reaction byproduct gases. These ends are connected to a fourth electric gas valve 64 for switching the gas supply. The gas supply line of the anode chamber 51 is also connected in series with a third electric gas valve 56 for switching the carbon dioxide supply, a gas rotor flowmeter 57 for measuring carbon dioxide flow, and a nano-gas disk 59 for uniformly distributing carbon dioxide. The inlet of the third electric gas valve 56 is connected to an external carbon dioxide supply line. The gas rotor flowmeter 57 is located between the third electric gas valve 56 and the nano-gas disk 59. The nano-gas disk 59 is located at the bottom of the anode chamber 51 and connected to the outlet of the gas rotor flowmeter 57. The upper side of the anode chamber 51 is equipped with a microbial fuel cell outlet end 53, which is connected to a fifth storage tank 55 via a pipeline equipped with a twelfth electric valve 54 for switching the water supply.

[0021] The power regulation module includes an anode 52, a cathode 67, a supercapacitor 70 for storing electrical energy, six DC-DC converters for regulating voltage, a first carbon felt electrode 83, and a second carbon felt electrode 87. The anode 52 is located in the anode chamber 51 and is electrically connected to the supercapacitor 70 for catalyzing the electrochemical reaction. The cathode 67 is located in the cathode chamber 68 and is electrically connected to the supercapacitor 70 for completing the reduction reaction of the cathode 67. The supercapacitor 70 is also electrically connected to a multimeter 71 for detecting voltage data. The multimeter 71 is electrically connected to a computer 72 for recording and storing data. The six DC-DC converters are divided into a first group and a second group, and are all electrically connected to the supercapacitor 70. The first group of three DC-DC converters includes a first DC-DC converter 80, a second DC-DC converter 81, and a third DC-DC converter 82. The second group of three DC-DC converters includes a fourth DC-DC converter 84, a fifth DC-DC converter 85, and a sixth DC-DC converter 86. The first group of three DC-DC converters is electrically connected to the first carbon felt electrode 83 located in the methanogenic reaction chamber 42, which is used to form a non-uniform potential field to enhance methanogenic production. The second group of three DC-DC converters is electrically connected to the second carbon felt electrode 87 located in the hydrogen-producing reaction chamber 22, which is used to form a non-uniform potential field to enhance hydrogen production.

[0022] The integrated control module is an integrated signal processor 76 used to receive detection signals and intelligently control the gas supply. The first gas collecting bag 26 is connected to the integrated signal processor 76 through a pipeline equipped with a fifth electric gas valve 73 and a sixth electric gas valve 74. The fifth electric gas valve 73 is located near the first gas collecting bag 26 and is used for primary gas path opening and closing. The sixth electric gas valve 74 is located near the integrated signal processor 76 and is used for fine gas path control. The upper end of the integrated signal processor 76 is connected to the fifth gas collecting end 62 and the sixth gas collecting end 63 through a pipeline equipped with a seventh electric gas valve 75 for opening and closing the gas path. The four electric air valves 64 are connected. One side of the integrated signal processor 76 is connected to the COD detection outlet 77 located on the side of the fourth storage tank 34 for detecting the COD concentration of wastewater. The other side of the integrated signal processor 76 is connected to the third gas collection bag 79 of the gas collection module. The lower end of the integrated signal processor 76 is connected to the carbon dioxide inlet 78 located at the lower end of the cathode chamber 68 for supplying regulated carbon dioxide to the cathode chamber 68. The upper end of the cathode chamber 68 is provided with a carbon dioxide outlet 65, which is connected to the third gas collection bag 79 for collecting the carbon dioxide by-product gas of the cathode chamber 68.

[0023] Based on the above, the method of using the fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system provided in this embodiment includes the following steps: First, basic preparations were made for the pre-culture of functional microorganisms and the co-treatment of wastewater. On the one hand, to cultivate microorganisms and achieve carrier attachment culture, *E. coli*, *Clostridium*, and *Desulfovibrio* were cultured at 37°C and then attached to PA6 carrier particles 21 to form a hydrogen-producing microbial film. Anaerobic sludge was acclimatized and cultured in two batches and then attached to coconut shell activated carbon particles to form a methanogenic and electrogenic universal microbial film. At the same time, BG11 culture medium was prepared, sterilized at high temperature, and then inoculated with microalgae 66. On the other hand, the raw wastewater underwent ultrasonic-enzymatic co-treatment. After the raw wastewater entered the first storage tank 1, it was ultrasonically crushed for 30 minutes by an ultrasonic crusher 2 at a power of 150W with a working time of 5 seconds and an intermittent time of 10 seconds. Then, the first electric valve 3 was opened and the first peristaltic pump 4 was started to transport the crushed wastewater to the second storage tank 5, which has a built-in cellulase 6. Enzymatic treatment was carried out for 2 hours at pH=4.8 and 50°C to break down complex organic matter and improve the usability of the wastewater substrate.

[0024] Secondly, each process module is started sequentially in the order of dark fermentation module, anaerobic digestion module, and microbial fuel cell to complete the independent operation of each module and continuous influent and effluent control. The dark fermentation module is first purged with nitrogen to create an anaerobic environment in the hydrogen production reaction chamber 22, and PA6 carrier particles 21 with attached hydrogen-producing microbial membranes are added; the second electric valve 7 and the third electric valve 9 are opened, and the second peristaltic pump 8 is started to inject the pretreated wastewater in the second storage tank 5 into the hydrogen production reaction chamber 22 until the volume reaches 97%. After closing the above electric valves and peristaltic pump, the fifth electric valve 16 and the first electric gas valve 25 are opened to collect the hydrogen-rich mixed gas generated by the reaction into the first gas collection bag 26. At the same time, the third peristaltic pump 17 is started to realize the internal circulation of wastewater in the hydrogen production reaction chamber 22; after the dark fermentation reactor has been running for 8 hours, the fourth electric valve 13 is opened while the second electric valve 7 and the third electric valve 9 are kept open, and the second peristaltic pump 8 is started to realize the continuous influent and effluent of the reactor. The dark fermentation effluent flows into the third storage tank 14 through the dark fermentation discharge end 12.

[0025] Then, the anaerobic digestion module is purged with nitrogen to maintain anaerobic conditions in the methanogenic reaction chamber 42. Coconut shell activated carbon particles 41 with attached methanogenic microbial film are added. The sixth electric valve 27 and the seventh electric valve 29 are opened, and the fourth peristaltic pump 28 is started to inject the dark fermentation effluent from the third storage tank 14 into the methanogenic reaction chamber 42 until the volume reaches 97%. After closing the above electric valves and peristaltic pump, the ninth electric valve 36 and the second electric gas valve 45 are opened to collect the methane-rich mixed gas produced by the reaction into the second gas collection bag 46. At the same time, the fifth peristaltic pump 37 is started to achieve internal circulation of the wastewater in the methanogenic reaction chamber 42. After the anaerobic digestion reactor has been running for 3 days, the eighth electric valve 33 is opened while the sixth electric valve 27 and the seventh electric valve 29 remain open. The fourth peristaltic pump 28 is started to achieve continuous water intake and output from the reactor. The anaerobic digestion effluent flows into the fourth storage tank 34 through the anaerobic digestion discharge end 32.

[0026] Next, the microbial fuel cell module is purged with nitrogen to create an anaerobic environment in the anode chamber 51. Coconut shell activated carbon particles 61 with attached electrogenic microbial membranes are added. Simultaneously, the cultured microalgae 66 are centrifuged, and the bottom algal sludge is transferred to the cathode chamber 68. The tenth electric valve 47 and the eleventh electric valve 49 are opened, and the sixth peristaltic pump 48 is started to inject the anaerobic digestion effluent from the fourth storage tank 34 into the anode chamber 51 until the volume reaches 95%. After closing the aforementioned electric valves and peristaltic pump, the third electric gas valve 56, the fourth electric gas valve 64, and the seventh electric gas valve 75 are started, and the gas rotor flow meter 57 is adjusted to... External carbon dioxide is uniformly introduced into the anode chamber 51 through the nano gas disk 59, driving the carrier particles to form a fluidized state. The carbon dioxide generated by the reaction in the anode chamber 51 enters the cathode chamber 68 through the pipeline for photosynthesis by microalgae 66. At the same time, the voltage data is detected by the multimeter 71 and recorded and stored synchronously by the computer 72. After the reactor has been running stably for 1 day, the twelfth electric valve 54 is opened while the tenth electric valve 47 and the eleventh electric valve 49 are kept open. The sixth peristaltic pump 48 is started to realize continuous water intake and discharge of the reactor. The treated wastewater flows into the fifth storage tank 55 through the outlet end 53 of the microbial fuel cell.

[0027] Finally, the fifth electric gas valve 73 and the sixth electric gas valve 74 are opened, allowing the mixed gas produced by dark fermentation to be introduced from the first gas collection bag 26 into the integrated signal processor 76 of the integrated control module. The integrated signal processor 76 receives and analyzes in real time the inlet carbon dioxide content signal, the concentration signal of the COD detection outlet 77 on the side of the fourth storage tank 34, and the carbon dioxide content feedback signal of the third gas collection bag 79. Based on this, it intelligently adjusts the carbon dioxide supply to the cathode chamber 68. At the same time, it adjusts the first DC-DC converter 80, the second DC-DC converter 81, the third DC-DC converter 82, the fourth DC-DC converter 84, the fifth DC-DC converter 85, and the sixth DC-DC converter 86 of the power control module, so that the second carbon felt electrode 87 in the hydrogen production reaction chamber 22 and the first carbon felt electrode 83 in the methanogenic reaction chamber 42 form a non-uniform potential field that varies with the particle concentration at different heights in the reaction chamber, thereby enhancing the reaction efficiency of hydrogen production by dark fermentation and methanogenic production by anaerobic digestion, respectively. Then, the various modules of the system complete the linkage debugging and enter a continuous and stable operation state of multi-stage series connection of dark fermentation-anaerobic digestion-microbial fuel cell.

[0028] Example 2 The fermentation effluent can also be treated via a second tandem pathway (dark fermentation - microbial fuel cell - anaerobic digestion). First, the chemical energy in more volatile fatty acids is converted into electrical energy using a microbial fuel cell process. Then, anaerobic digestion is used for tailings treatment, producing methane to handle the remaining complex organic matter. This embodiment differs from Example 1 in that it employs a second tandem pathway, such as... Figure 2 As shown, the system includes: The pretreatment module includes a first storage tank 1 and a second storage tank 5 connected in sequence by pipelines. The first storage tank 1 is connected to an ultrasonic crusher 2 for ultrasonically crushing the raw wastewater and breaking down complex organic matter. The connecting pipeline between the first storage tank 1 and the second storage tank 5 is sequentially equipped with a first electric valve 3 for switching the wastewater delivery pipeline on and off and a first peristaltic pump for quantitatively delivering wastewater. The second storage tank 5 contains a cellulase 6 for biologically enzymatically hydrolyzing the ultrasonically crushed wastewater and degrading cellulose organic matter.

[0029] The dark fermentation module includes a hydrogen production submersible chamber 20, a first liquid distributor 11 for uniform water distribution, and a hydrogen production reaction chamber 22. A second storage tank 5 is connected to the dark fermentation feed end 10 on one side of the hydrogen production submersible chamber 20 via a pipeline equipped with a second electric valve 7. This pipeline is also equipped with a second peristaltic pump 8 for quantitative wastewater transport and a third electric valve 9 for auxiliary pipeline switching. The third electric valve 9 is located near the dark fermentation feed end 10. The second peristaltic pump 8 is positioned between the second electric valve 7 and the third electric valve 9, with the second electric valve 7 located near the second storage tank 5. The hydrogen production submersible chamber 20 is connected to the hydrogen production reaction chamber 22 via the first liquid distributor 11. The hydrogen production reaction chamber 22 is filled with PA6 carrier particles 21 dispersed in the liquid environment for attaching hydrogen-producing microbial films. A dark fermentation circulation discharge end 15 is located at the bottom of the upper end of the hydrogen production reaction chamber 22. The feed end 15 is connected to the dark fermentation circulation feed end 19 via a pipeline equipped with a fifth electric valve 16. A third peristaltic pump 17 for driving the internal circulation of wastewater and a first liquid flow meter 18 for measuring the volume of circulating wastewater are also connected in series on the connecting pipeline. The third peristaltic pump 17 is located near the dark fermentation circulation discharge end 15, and the first liquid flow meter 18 is located near the dark fermentation circulation feed end 19. The upper top of the hydrogen production reaction chamber 22 is provided with a first gas collecting end 23 and a second gas collecting end 24 for collecting hydrogen production reaction gases. The first gas collecting end 23 and the second gas collecting end 24 are connected to the first gas collecting bag 26 of the gas collecting module via a pipeline equipped with a first electric valve 25 for opening and closing the gas path. The upper side of the hydrogen production reaction chamber 22 is provided with a dark fermentation discharge end 12. The dark fermentation discharge end 12 is connected to the third storage tank 14 via a pipeline equipped with a fourth electric valve 13 for opening and closing the water outlet pipeline.

[0030] The microbial fuel cell module includes a power generation submersible chamber 38, a second liquid distributor 40 for uniform water distribution, an anode chamber 31, and a cathode chamber 48. A third storage tank 14 is connected to the microbial fuel cell feed end 30 on one side of the power generation submersible chamber 38 via a pipeline equipped with a seventh electric valve 29. This connecting pipeline is also sequentially equipped with a sixth electric valve 27 for opening and closing the pipeline and a fourth peristaltic pump 28 for quantitatively transporting wastewater. The sixth electric valve 27 is located near the third storage tank 14, and the fourth peristaltic pump 28 is located between the sixth electric valve 27 and the seventh electric valve 29. The seventh electric valve 29 is located near the feed end 30 of the microbial fuel cell. The power generation liquid chamber 38 is connected to the anode chamber 31 via the second liquid distributor 40. The anode chamber 31 is filled with coconut shell activated carbon particles 41 dispersed in the liquid environment for attaching the power generation microbial film. A proton exchange membrane 49 for proton conduction is provided on the side of the anode chamber 31. The other side of the proton exchange membrane 49 is in contact with the cathode chamber 48. The cathode chamber 48 is filled with microalgae 46 for photosynthetic reactions using carbon dioxide, and the microalgae 46 are dispersed in the liquid environment of the cathode chamber 48. In the phase environment; the upper top of the anode chamber 31 is provided with a third gas collecting end 42 and a fourth gas collecting end 43 for collecting reaction by-product gases. The third gas collecting end 42 and the fourth gas collecting end 43 are connected to the integrated control module through pipelines equipped with a third electric gas valve 44 for switching on and off the gas path; the upper side of the anode chamber 31 is provided with a microbial fuel cell outlet end 33, which is connected to the fourth storage tank 35 through a pipeline equipped with an eighth electric valve 34 for switching on and off the water outlet pipeline; the gas supply pipeline of the microbial fuel cell module is also connected in series with a valve for switching on and off the carbon dioxide supply. The anode chamber 31 includes a second electric air valve 36, a gas rotor flow meter 37 for measuring carbon dioxide flow, and a nano gas disk 39 for uniformly distributing carbon dioxide. The inlet of the second electric air valve 36 is connected to an external carbon dioxide supply pipeline. The gas rotor flow meter 37 is located between the second electric air valve 36 and the nano gas disk 39. The nano gas disk 39 is located at the bottom of the anode chamber 31 and is connected to the outlet of the gas rotor flow meter 37. The outlet of the nano gas disk 39 faces the interior of the anode chamber 31 and is used to drive the carrier particles in the anode chamber 31 to form a fluidized state.

[0031] The anaerobic digestion module includes a methanogenic lower liquid chamber 66, a third liquid distributor 57 for uniform water distribution, and a methanogenic reaction chamber 68. A fourth storage tank 35 is connected to the anaerobic digestion feed end 56 on one side of the methanogenic lower liquid chamber 66 via a pipeline equipped with a tenth electric valve 55. This connecting pipeline is also equipped with a ninth electric valve 53 for opening and closing the pipeline and a fifth peristaltic pump 54 for quantitative wastewater transport. The ninth electric valve 53 is located near the fourth storage tank 35, and the fifth peristaltic pump 54 is located between the ninth electric valve 53 and the tenth electric valve 55. The tenth electric valve 55 is located near the anaerobic digestion feed end 56. The methanogenic lower liquid chamber 66 is connected to the methanogenic reaction chamber 68 via the third liquid distributor 57. The methanogenic reaction chamber 68 is filled with coconut shell activated carbon particles 67 dispersed in the liquid phase environment for attaching methanogenic microbial films. An anaerobic digestion circulating discharge end 61 is located at the top and bottom of the methanogenic reaction chamber 68. The anaerobic digestion cycle discharge end 61 is connected to the anaerobic digestion cycle feed end 65 via a pipeline equipped with a twelfth electric valve 62. A sixth peristaltic pump 63 for driving the internal circulation of wastewater and a third liquid flow meter 64 for measuring the volume of circulating wastewater are also connected in series on this pipeline. The sixth peristaltic pump 63 is positioned near the anaerobic digestion cycle discharge end 61, and the third liquid flow meter 64 is positioned near the anaerobic digestion cycle feed end 65. The top of the methanogenic reaction chamber 68 is equipped with a fifth gas collecting end 69 and a sixth gas collecting end 70 for collecting methanogenic reaction gases. The fifth gas collecting end 69 and the sixth gas collecting end 70 are connected to the second gas collecting bag 72 of the gas collecting module via a pipeline equipped with a fourth electric valve 71 for switching the gas path on and off. The upper side of the methanogenic reaction chamber 68 is equipped with an anaerobic digestion discharge end 58, which is connected to the fifth storage tank 60 via a pipeline equipped with an eleventh electric valve 59 for switching the effluent pipeline on and off.

[0032] The power regulation module includes an anode 32, a cathode 47, a supercapacitor 50 for storing electrical energy, six DC-DC converters for regulating voltage, a first carbon felt electrode 86, and a second carbon felt electrode 87. The anode 32 is located in the anode chamber 31 and electrically connected to the supercapacitor 50 for catalyzing the electrochemical reaction. The cathode 47 is located in the cathode chamber 48 and electrically connected to the supercapacitor 50 for completing the cathode 47 reduction reaction. The supercapacitor 50 is also electrically connected to a multimeter 51 for detecting voltage data, and the multimeter 51 is electrically connected to a computer 52 for recording and storing data. The six DC-DC converters are divided into a first group and a second group, both of which are electrically connected to the supercapacitor 50. The first group includes a first DC-DC converter 80, a second DC-DC converter 81, and a third DC-DC converter 82, and the second group includes a fourth DC-DC converter 83, a fifth DC-DC converter 84, and a sixth DC-DC converter 85. The first group of three DC-DC converters is electrically connected to the first carbon felt electrode 86 located in the methanogenic reaction chamber 68, which is used to form a non-uniform potential field to enhance methanogenic production. The second group of three DC-DC converters is electrically connected to the second carbon felt electrode 87 located in the hydrogen-producing reaction chamber 22, which is used to form a non-uniform potential field to enhance hydrogen production.

[0033] The integrated control module is an integrated signal processor 76 used to receive detection signals and intelligently control the gas supply. The first gas collecting bag 26 is connected to the integrated signal processor 76 through a pipeline equipped with a fifth electric gas valve 73 and a sixth electric gas valve 74. The fifth electric gas valve 73 is located near the first gas collecting bag 26 and is used for primary gas path opening and closing. The sixth electric gas valve 74 is located on the side of the integrated signal processor 76 and is used for fine gas path control. The upper end of the integrated signal processor 76 is connected to the third gas collecting end 42 and the fourth gas collecting end 43 through a pipeline equipped with a seventh electric gas valve 75 for opening and closing the gas path. The three electric air valves 44 are connected; one side of the integrated signal processor 76 is connected to the COD detection outlet 77 located on the side of the fourth storage tank 35 for detecting the COD concentration of wastewater, and the other side of the integrated signal processor 76 is connected to the third gas collection bag 79 of the gas collection module; the lower end of the integrated signal processor 76 is connected to the carbon dioxide inlet 78 located at the lower end of the cathode chamber 48 for supplying regulated carbon dioxide to the cathode chamber 48; the upper end of the cathode chamber 48 is provided with a carbon dioxide outlet 45, which is connected to the third gas collection bag 79 for collecting the carbon dioxide by-product gas of the cathode chamber 48.

[0034] Based on the above, the method of using the fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system provided in this embodiment includes the following steps: First, *Escherichia coli*, *Clostridium*, and *Desulfovibrio* were inoculated using a sterile inoculation loop. A nutrient solution rich in glucose, various inorganic substances, and trace elements was prepared and cultured at 37°C until the microbial activity reached the target. Then, PA6 carrier particles 21 were added to allow the microorganisms to attach to the particle surface and form a hydrogen-producing microbial film. Anaerobic sludge from a long-term anaerobic digester was inoculated, and methanogenic and electrogenic bacteria were acclimatized and cultured in two batches. The first batch was cultured in a nutrient solution rich in glucose and cellulose, and the second batch was cultured in a nutrient solution rich in sodium acetate and cellulose. After the bacterial activity reached the target, coconut shell activated carbon particles were added to form a universal microbial film for both electrogenic and methanogenic processes. BG11 medium was prepared, the pH was adjusted to 7.1±0.1, and after sterilization at 120°C, microalgae 46 were inoculated to complete the cultivation of functional bacteria in the cathode chamber 48. On the other hand, wastewater pretreatment is carried out. The raw wastewater enters the first storage tank 1 and is crushed by the ultrasonic crusher 2 at a time of 30 minutes, 150W power, and 5 seconds working / 10 seconds intermittent. Then, the first electric valve 3 is opened and the first peristaltic pump 4 is started to send the crushed wastewater into the second storage tank 5. Relying on the cellulase 6 system with a cellulase activity of 8 FPU / mL in the tank, the wastewater is enzymatically hydrolyzed for 2 hours at pH=4.8 and temperature of 50℃ to break down the recalcitrant organic matter in the wastewater and improve the utilization rate of substrates in subsequent processes.

[0035] Secondly, each unit is started in sequence according to the dark fermentation module, the microbial fuel cell module, and the anaerobic digestion module, and continuous water inflow and outflow are achieved. First, start the dark fermentation module and maintain the anaerobic environment of the hydrogen production reaction chamber 22 by purging with nitrogen. Add PA6 carrier particles 21 with attached hydrogen-producing microbial film. Open the second electric valve 7 and the third electric valve 9, start the second peristaltic pump 8, and inject the pretreated wastewater in the second storage tank 5 into the hydrogen production reaction chamber 22. When the wastewater volume occupies 97% of the reaction chamber, close the above electric valves and peristaltic pump, open the fifth electric valve 16 and the first electric gas valve 25, and collect the hydrogen-rich mixed gas generated by the reaction into the first gas collection bag 26. At the same time, start the third peristaltic pump 17 to realize the internal liquid circulation of the reactor through the dark fermentation circulation discharge end 15 and the dark fermentation circulation feed end 19. After the dark fermentation reactor has been running for 8 hours, open the second electric valve 7, the third electric valve 9, and the fourth electric valve 13, and keep the second peristaltic pump 8 running to realize the continuous water intake and output of the reactor. The water flows into the third storage tank 14 through the dark fermentation discharge end 12.

[0036] Then, the microbial fuel cell module is started. Nitrogen purging is used to maintain anaerobic conditions in the anode chamber 31. Coconut shell activated carbon particles 41 with attached electrogenic microorganisms are added. The cultured microalgae 46 are centrifuged, and the bottom algal sludge is transferred to the cathode chamber 48. The sixth electric valve 27 and the seventh electric valve 29 are opened, and the fourth peristaltic pump 28 is started. The effluent from the dark fermentation in the third storage tank 14 is injected into the anode chamber 31 until the wastewater volume occupies 95% of the anode chamber 31. Then, the electric valves and peristaltic pump are closed, and the second electric air valve 36 and the third electric air valve 44 are started to adjust... Gas rotor flowmeter 37 allows external carbon dioxide to be evenly introduced into anode chamber 31 through nano gas disk 39, driving the carrier particles to form a fluidized state. The carbon dioxide produced by the reaction in anode chamber 31 is simultaneously introduced into cathode chamber 48 for use by microalgae 46. The voltage generated is detected by multimeter 51 and the data is recorded in real time by computer 52. After the reactor has been running stably for 1 day, the seventh electric valve 29 and the eighth electric valve 34 are opened to keep the fourth peristaltic pump 28 running, so as to achieve continuous water intake and output. The water flows into the fourth storage tank 35 through the outlet end 33 of the microbial fuel cell.

[0037] Next, the anaerobic digestion module is started. Nitrogen purging is used to maintain an anaerobic environment in the methanogenic reaction chamber 68. Coconut shell activated carbon particles 67 with attached methanogenic microorganisms are added. The ninth electric valve 53 and the tenth electric valve 55 are opened, and the fifth peristaltic pump 54 is started to inject the effluent from the microbial fuel cell in the fourth storage tank 35 into the methanogenic reaction chamber 68. When the wastewater volume occupies 97% of the reaction chamber, the above electric valves and peristaltic pump are closed. The twelfth electric valve 62 and the fourth electric gas valve 71 are opened to collect the methane-rich mixed gas produced by the reaction into the second gas collection bag 72. At the same time, the sixth peristaltic pump 63 is started to achieve internal liquid circulation in the reactor through the anaerobic digestion circulation discharge end 61 and the anaerobic digestion circulation feed end 65. After the anaerobic digestion reactor has been running for 3 days, the tenth electric valve 55 and the eleventh electric valve 59 are opened, and the fifth peristaltic pump 54 is kept running to achieve continuous water intake and discharge. The treated wastewater that meets the standards flows into the fifth storage tank 60 through the anaerobic digestion discharge end 58.

[0038] Finally, the fifth electric gas valve 73 and the sixth electric gas valve 74 are opened, allowing the mixed gas containing hydrogen and carbon dioxide produced by the dark fermentation in the first gas collection bag 26 to be introduced into the integrated signal processor 76. The processor analyzes the inlet carbon dioxide content signal, the wastewater COD concentration signal from the COD detection outlet 77 on one side of the fourth storage tank 35, and the carbon dioxide content feedback signal from the third gas collection bag 79, and precisely controls the amount of carbon dioxide supplied to the cathode chamber 48. Simultaneously, the first DC-DC converter 80, the second DC-DC converter 81, the third DC-DC converter 82, the fourth DC-DC converter 83, the fifth DC-DC converter 84, and the sixth DC-DC converter 85 are adjusted, and the electrical energy produced by the microbial fuel cell is applied to the first carbon felt electrode 86 in the methanogenic reaction chamber 68 and the second carbon felt electrode 87 in the hydrogen-producing reaction chamber 22 after voltage regulation. This creates a non-uniform potential field in the two reaction chambers that dynamically adjusts with particle concentration, enhancing the electrochemical reaction efficiency of hydrogen- and methanogenic microorganisms and improving the overall energy recovery effect of the system. At this point, the second series-path multi-stage reactor enters a continuous and stable operating state.

[0039] Therefore, by adopting the above-mentioned fluidized multi-stage anaerobic process in conjunction with wastewater treatment and energy recovery system, the deep purification of wastewater and the cascade conversion and recovery of organic chemical energy into hydrogen, methane and electrical energy are achieved. Through multi-stage synergistic treatment, organic matter is degraded and nitrogen and phosphorus are removed, ensuring that the effluent meets the standards while improving energy conversion efficiency and system operation stability.

[0040] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A fluidized bed multi-stage anaerobic process combined with wastewater treatment and energy recovery system, characterized in that, It includes a pretreatment module, a dark fermentation module, an anaerobic digestion module, a microbial fuel cell module, a gas collection module, an energy regulation module, and a comprehensive regulation module; The pretreatment module is connected to the feed end of the dark fermentation module, and the discharge end of the dark fermentation module is connected to the feed end of the anaerobic digestion module and the feed end of the microbial fuel cell module, forming a first series path of dark fermentation-anaerobic digestion-microbial fuel cell and a second series path of dark fermentation-microbial fuel cell-anaerobic digestion. The gas collection module is connected to the gas collection ends of the dark fermentation module, the anaerobic digestion module, and the microbial fuel cell module, respectively, and is used to collect the gas generated by each module. The power regulation module is electrically connected to the power generation end of the microbial fuel cell module, and the power regulation module is also electrically connected to the electrode components in the dark fermentation module and the anaerobic digestion module, for applying the power generated by the microbial fuel cell module to the dark fermentation module and the anaerobic digestion module. The integrated control module is connected to the signal detection terminals and gas pipelines of the gas collection module, the microbial fuel cell module, the anaerobic digestion module, and the dark fermentation module, respectively, and is used to receive detection signals and regulate the gas supply of each module.

2. The fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system according to claim 1, characterized in that, The specific structure of the first serial path is as follows: The pretreatment module includes a first storage tank and a second storage tank connected in sequence by a pipeline. An ultrasonic crusher is connected to the first storage tank. A first electric valve and a first peristaltic pump are installed in sequence on the pipeline connecting the first storage tank and the second storage tank. The dark fermentation module includes a hydrogen production liquid chamber, a first liquid distributor, and a hydrogen production reaction chamber. The second storage tank is connected to the dark fermentation feed end on one side of the hydrogen production liquid chamber via a pipeline equipped with a second electric valve. The hydrogen production liquid chamber is connected to the hydrogen production reaction chamber via the first liquid distributor. The bottom of the upper end of the hydrogen production reaction chamber is provided with a dark fermentation circulation discharge end. The dark fermentation circulation discharge end is connected to the dark fermentation circulation feed end via a pipeline equipped with a fifth electric valve. The top of the upper end of the hydrogen production reaction chamber is provided with a first gas collection end and a second gas collection end. The first gas collection end and the second gas collection end are connected to the first gas collection bag of the gas collection module via a pipeline equipped with a first electric gas valve. The side of the upper end of the hydrogen production reaction chamber is provided with a dark fermentation discharge end. The dark fermentation discharge end is connected to the third storage tank via a pipeline equipped with a fourth electric valve. The anaerobic digestion module includes a methanogenic liquid chamber, a second liquid distributor, and a methanogenic reaction chamber. The third storage tank is connected to the anaerobic digestion feed end on one side of the methanogenic liquid chamber via a pipeline equipped with a seventh electric valve. The methanogenic liquid chamber is connected to the methanogenic reaction chamber via the second liquid distributor. An anaerobic digestion circulation discharge end is provided at the bottom of the upper end of the methanogenic reaction chamber. The anaerobic digestion circulation discharge end is connected to the anaerobic digestion circulation feed end via a pipeline equipped with a ninth electric valve. A third gas collection end and a fourth gas collection end are provided at the top of the upper end of the methanogenic reaction chamber. The third and fourth gas collection ends are connected to the second gas collection bag of the gas collection module via a pipeline equipped with a second electric gas valve. An anaerobic digestion discharge end is provided on the side of the upper end of the methanogenic reaction chamber. The anaerobic digestion discharge end is connected to the fourth storage tank via a pipeline equipped with an eighth electric valve. The microbial fuel cell module includes a power generation liquid chamber, a third liquid distributor, an anode chamber, and a cathode chamber. The fourth storage tank is connected to the feed end of the microbial fuel cell in the power generation liquid chamber through a pipeline equipped with a tenth electric valve. The power generation liquid chamber is connected to the anode chamber through the third liquid distributor. A proton exchange membrane is provided on the side of the anode chamber, and the other side of the proton exchange membrane is in contact with the cathode chamber. A fifth gas collection end and a sixth gas collection end are provided at the top of the anode chamber. The fifth gas collection end and the sixth gas collection end are connected to the fourth electric gas valve. A microbial fuel cell outlet end is provided on the side of the top of the anode chamber. The microbial fuel cell outlet end is connected to the fifth storage tank through a pipeline equipped with a twelfth electric valve. The power control module includes an anode, a cathode, a supercapacitor, six DC-DC converters, a first carbon felt electrode, and a second carbon felt electrode. The anode is located in the anode chamber and is electrically connected to the supercapacitor. The cathode is located in the cathode chamber and is electrically connected to the supercapacitor. The supercapacitor is also electrically connected to a multimeter, which is electrically connected to a computer. The six DC-DC converters are divided into a first group and a second group, both of which are electrically connected to the supercapacitor. The three DC-DC converters in the first group are electrically connected to the first carbon felt electrode located in the methanogenic reaction chamber, and the three DC-DC converters in the second group are electrically connected to the second carbon felt electrode located in the hydrogen-producing reaction chamber. The integrated control module is an integrated signal processor. The first gas collection bag is connected to the integrated signal processor through a pipeline equipped with a fifth electric air valve and a sixth electric air valve. The fifth electric air valve is located on the side closer to the first gas collection bag, and the sixth electric air valve is located on the side closer to the integrated signal processor. The upper end of the integrated signal processor is connected to a fourth electric air valve, which is connected to the fifth and sixth gas collection ends, through a pipeline equipped with a seventh electric air valve. One side of the integrated signal processor is connected to the COD detection outlet located on the side of the fourth storage tank, and the other side of the integrated signal processor is connected to the third gas collection bag of the gas collection module. The lower end of the integrated signal processor is connected to the carbon dioxide inlet located at the lower end of the cathode chamber. The upper end of the cathode chamber is equipped with a carbon dioxide outlet, which is connected to the third gas collection bag.

3. The fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system according to claim 2, characterized in that, The second storage tank also contains cellulase, the hydrogen production reaction chamber is filled with PA6 carrier particles, the methanogenic reaction chamber is filled with coconut shell activated carbon particles, the anode chamber is also filled with coconut shell activated carbon particles, and the cathode chamber is filled with microalgae. Each particle is dispersed in the liquid phase environment of its corresponding chamber.

4. The fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system according to claim 2, characterized in that, A second peristaltic pump and a third electric valve are also installed on the connecting pipeline between the second storage tank and the dark fermentation feed end. The third electric valve is located near the dark fermentation feed end, and the second peristaltic pump is located between the second and third electric valves. The second electric valve is located near the second storage tank. A third peristaltic pump and a first liquid flow meter are also installed in series on the connecting pipeline between the dark fermentation circulation discharge end and the dark fermentation circulation feed end. The third peristaltic pump is located near the dark fermentation circulation discharge end, and the first liquid flow meter is located near the dark fermentation circulation feed end.

5. The fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system according to claim 2, characterized in that, A sixth electric valve and a fourth peristaltic pump are also installed on the connecting pipeline between the third storage tank and the anaerobic digestion feed end. The sixth electric valve is located near the third storage tank, and the fourth peristaltic pump is located between the sixth and seventh electric valves, with the seventh electric valve located near the anaerobic digestion feed end. A fifth peristaltic pump and a second liquid flow meter are also connected in series on the connecting pipeline between the anaerobic digestion circulation discharge end and the anaerobic digestion circulation feed end. The fifth peristaltic pump is located near the anaerobic digestion circulation discharge end, and the second liquid flow meter is located near the anaerobic digestion circulation feed end.

6. The fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system according to claim 2, characterized in that, A sixth peristaltic pump and an eleventh electric valve are also installed on the connecting pipeline between the fourth storage tank and the feed end of the microbial fuel cell. The eleventh electric valve is located near the feed end of the microbial fuel cell, and the sixth peristaltic pump is located between the tenth and eleventh electric valves. The tenth electric valve is located near the fourth storage tank. A third electric gas valve, a gas rotor flow meter, and a nano gas disc are also connected in series on the gas supply pipeline of the anode chamber. The inlet of the third electric gas valve is connected to the external carbon dioxide supply pipeline. The gas rotor flow meter is located between the third electric gas valve and the nano gas disc. The nano gas disc is located at the bottom of the anode chamber and is connected to the outlet pipeline of the gas rotor flow meter.

7. The fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system according to claim 1, characterized in that, The specific structure of the second serial path is as follows: The pretreatment module includes a first storage tank and a second storage tank connected in sequence by a pipeline. An ultrasonic crusher is connected to the first storage tank. A first electric valve and a first peristaltic pump are installed in sequence on the pipeline connecting the first storage tank and the second storage tank. The dark fermentation module includes a hydrogen production liquid chamber, a first liquid distributor, and a hydrogen production reaction chamber. The second storage tank is connected to the dark fermentation feed end on one side of the hydrogen production liquid chamber via a pipeline equipped with a second electric valve. The hydrogen production liquid chamber is connected to the hydrogen production reaction chamber via the first liquid distributor. The bottom of the upper end of the hydrogen production reaction chamber is provided with a dark fermentation circulation discharge end. The dark fermentation circulation discharge end is connected to the dark fermentation circulation feed end via a pipeline equipped with a fifth electric valve. The top of the upper end of the hydrogen production reaction chamber is provided with a first gas collection end and a second gas collection end. The first gas collection end and the second gas collection end are connected to the first gas collection bag of the gas collection module via a pipeline equipped with a first electric gas valve. The side of the upper end of the hydrogen production reaction chamber is provided with a dark fermentation discharge end. The dark fermentation discharge end is connected to the third storage tank via a pipeline equipped with a fourth electric valve. The microbial fuel cell module includes a power generation liquid chamber, a second liquid distributor, an anode chamber, and a cathode chamber. The third storage tank is connected to the microbial fuel cell feed end on one side of the power generation liquid chamber via a pipeline equipped with a seventh electric valve. The power generation liquid chamber is connected to the anode chamber via the second liquid distributor. A proton exchange membrane is provided on the side of the anode chamber, and the other side of the proton exchange membrane is in contact with the cathode chamber. A third gas collection end and a fourth gas collection end are provided at the top of the anode chamber. The third gas collection end and the fourth gas collection end are connected to the integrated control module via a pipeline equipped with a third electric gas valve. A microbial fuel cell outlet end is provided on the side of the top of the anode chamber. The microbial fuel cell outlet end is connected to the fourth storage tank via a pipeline equipped with an eighth electric valve. The anaerobic digestion module includes a methanogenic liquid chamber, a third liquid distributor, and a methanogenic reaction chamber. The fourth storage tank is connected to the anaerobic digestion feed end on one side of the methanogenic liquid chamber via a pipeline equipped with a tenth electric valve. The methanogenic liquid chamber is connected to the methanogenic reaction chamber via the third liquid distributor. An anaerobic digestion circulation discharge end is provided at the bottom of the upper end of the methanogenic reaction chamber. The anaerobic digestion circulation discharge end is connected to the anaerobic digestion circulation feed end via a pipeline equipped with a twelfth electric valve. A fifth gas collection end and a sixth gas collection end are provided at the top of the upper end of the methanogenic reaction chamber. The fifth and sixth gas collection ends are connected to the second gas collection bag of the gas collection module via a pipeline equipped with a fourth electric gas valve. An anaerobic digestion discharge end is provided on the side of the upper end of the methanogenic reaction chamber. The anaerobic digestion discharge end is connected to the fifth storage tank via a pipeline equipped with an eleventh electric valve. The power control module includes an anode, a cathode, a supercapacitor, six DC-DC converters, a first carbon felt electrode, and a second carbon felt electrode. The anode is located in the anode chamber and is electrically connected to the supercapacitor. The cathode is located in the cathode chamber and is electrically connected to the supercapacitor. The supercapacitor is also electrically connected to a multimeter, which is electrically connected to a computer. The six DC-DC converters are divided into a first group and a second group, both of which are electrically connected to the supercapacitor. The three DC-DC converters in the first group are electrically connected to the first carbon felt electrode located in the methanogenic reaction chamber, and the three DC-DC converters in the second group are electrically connected to the second carbon felt electrode located in the hydrogen-producing reaction chamber. The integrated control module is an integrated signal processor. The first gas collection bag is connected to the integrated signal processor through a pipeline equipped with a fifth electric air valve and a sixth electric air valve. The fifth electric air valve is located on the side near the first gas collection bag, and the sixth electric air valve is located on the side of the integrated signal processor. The upper end of the integrated signal processor is connected to the third electric air valve, which is connected to the third and fourth gas collection ends, through a pipeline equipped with a seventh electric air valve. One side of the integrated signal processor is connected to the COD detection outlet located on the side of the fourth storage tank, and the other side of the integrated signal processor is connected to the third gas collection bag of the gas collection module. The lower end of the integrated signal processor is connected to the carbon dioxide inlet located at the lower end of the cathode chamber. The upper end of the cathode chamber is equipped with a carbon dioxide outlet, which is connected to the third gas collection bag.

8. The fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system according to claim 7, characterized in that, A second peristaltic pump and a third electric valve are also installed on the connecting pipeline between the second storage tank and the dark fermentation feed end. The third electric valve is located near the dark fermentation feed end, and the second peristaltic pump is located between the second electric valve and the third electric valve. A third peristaltic pump and a first liquid flow meter are also installed in series on the connecting pipeline between the dark fermentation circulation discharge end and the dark fermentation circulation feed end. The third peristaltic pump is located near the dark fermentation circulation discharge end, and the first liquid flow meter is located near the dark fermentation circulation feed end.

9. The fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system according to claim 7, characterized in that, A sixth electric valve and a fourth peristaltic pump are sequentially installed on the connecting pipeline between the third storage tank and the feed end of the microbial fuel cell. The sixth electric valve is located near the third storage tank, and the fourth peristaltic pump is located between the sixth and seventh electric valves. The seventh electric valve is located near the feed end of the microbial fuel cell. A second electric gas valve, a gas rotor flow meter, and a nano gas disc are also connected in series on the gas supply pipeline of the microbial fuel cell module. The inlet of the second electric gas valve is connected to an external carbon dioxide supply pipeline. The gas rotor flow meter is located between the second electric gas valve and the nano gas disc. The nano gas disc is located at the bottom of the anode chamber and is connected to the outlet pipeline of the gas rotor flow meter. The outlet of the nano gas disc faces the inside of the anode chamber to drive the fluidization of the carrier particles in the anode chamber.

10. The fluidized bed multi-stage anaerobic process synergistic wastewater treatment and energy recovery system according to claim 7, characterized in that, The anaerobic digestion module is also equipped with a ninth electric valve and a fifth peristaltic pump on its pipeline. The fifth peristaltic pump is located between the ninth and tenth electric valves. The ninth electric valve is located near the fourth storage tank, and the tenth electric valve is located near the anaerobic digestion feed end. A sixth peristaltic pump and a third liquid flow meter are connected in series on the pipeline connecting the anaerobic digestion circulation discharge end and the anaerobic digestion circulation feed end. The sixth peristaltic pump is located near the anaerobic digestion circulation discharge end, and the third liquid flow meter is located near the anaerobic digestion circulation feed end.

Images