Aerobic biological reaction device enhanced by external power supply and application of aerobic biological reaction device

Abstract

The invention relates to the crossing field of biotechnology and environmental engineering, in particular to an external power supply enhanced aerobic biological reaction device and application thereof. Comprising a reaction box, a plurality of plug-in limiting frames arranged in the reaction box in parallel, an electrode frame body detachably arranged on the plug-in limiting frames, a plurality of carbon fiber brushes arranged on the electrode frame body, a direct-current power supply connected with the carbon fiber brushes, and an aeration mechanism arranged below the carbon fiber brushes. By applying direct current, the electron transfer process of microorganisms is accelerated, oxygenolysis of a substrate and synthesis of PHA are promoted, and the yield and synthesis rate of PHA are remarkably improved. The micro electric field formed by the direct current can influence the metabolic pathway and growth rate of the microorganisms, so that the microorganisms reach the optimal growth state within a shorter time, and synthesis of PHA is facilitated. By improving the synthesis efficiency and yield of PHA, the production cost is reduced, and a more competitive solution is provided for the production of bioplastics.

Description

Technical Field

[0001] The present invention relates to the intersecting field of biotechnology and environmental engineering, and in particular to an aerobic biological reaction device enhanced by an external power supply and its application. Background Art

[0002] Conventional dairy wastewater is rich in lactose, proteins, fats, carbohydrates, and nutrients, resulting in adverse environmental impacts, including eutrophication, algal blooms, and severe oxygen depletion. Furthermore, the application of clean-in-place (CIP) protocols for cleaning equipment and tools in the dairy industry leads to the accumulation of reagents in the wastewater, such as caustic detergent solutions, surfactants, and chlorine, which can increase the chemical oxygen demand (COD) of the wastewater by up to 10%. The composition of dairy wastewater varies depending on the milk processing technology. Consequently, a wide range of COD, biochemical oxygen demand (BOD), total suspended solids (TSS), pH, total phosphorus (TP), total nitrogen (TN), and oil and fat has been observed in dairy wastewater. Key factors affecting dairy wastewater characteristics are the operations performed, the processing of different dairy products, and the management strategies implemented. Furthermore, dairy wastewater is characterized by a wide range of volumes and flow rates, requiring the implementation of complex treatment mechanisms to meet wastewater discharge standards and sustainability goals. Therefore, selecting efficient and environmentally friendly technologies to treat dairy wastewater is a major challenge.

[0003] At present, the treatment of dairy wastewater mainly adopts aerobic biological treatment or anaerobic fermentation to achieve the purpose of harmless and energy-based treatment of dairy wastewater. The treatment of dairy wastewater can also produce volatile fatty acids (VFA) through anaerobic fermentation. As an important intermediate metabolite in the anaerobic fermentation process, VFA has a wider range of uses and higher economic value compared to the production of methane. In addition to being used in the fields of medicine and food, organic acids such as VFA produced by anaerobic fermentation can also be used to produce high-value-added products - biodegradable materials polyhydroxyalkanoates (PHA).

[0004] Polyhydroxyalkanoates (PHA) are biodegradable plastics synthesized by microorganisms and have broad application prospects. However, the current production cost of PHA is high, and one of the main limiting factors is the low efficiency of microbial PHA synthesis. Traditional fermentation processes for PHA synthesis are often restricted by multiple factors, including microbial growth rate, substrate utilization, and product extraction efficiency.

[0005] The sequencing batch biofilm reactor (SBBR), a wastewater treatment process that combines activated sludge and biofilm processes, offers significant advantages in microbial treatment. However, its application in PHA synthesis still faces challenges such as uneven biofilm growth and low substrate conversion efficiency. Therefore, a more effective enhancement method is needed to improve the efficiency of SBBR in PHA synthesis.

[0006] Electron-enhanced biotechnology (BES) is a novel wastewater treatment technology that stimulates microorganisms by applying an additional electric field, combining microbial metabolism with electrochemical redox reactions. It is also a key component of bioelectrochemical systems. The electric field applied in BES enhances electron transfer between microorganisms, increases cell membrane permeability, improves microbial activity, influences microbial community structure, and promotes the enrichment of functional microorganisms, thereby improving the efficiency and effectiveness of biological treatment. Previous studies have shown that direct current can accelerate electron transfer in microorganisms, promoting the oxidative decomposition of substrates and the synthesis of products.

[0007] However, after prolonged operation, the biofilm can become excessively thick, increasing mass transfer resistance: nutrients and metabolites have difficulty effectively diffusing into the biofilm or reaching the electrode surface, reducing reaction efficiency. Microorganisms within the inner layer die due to lack of oxygen or nutrients, forming an inert layer that increases resistance and reduces electrode activity. Excessively thick or aged biofilms are structurally unstable and can detach over large areas, leading to a sharp decline in system performance. Therefore, timely replacement of the biofilm carrier is essential. Summary of the Invention

[0008] The purpose of the present invention is to provide an aerobic bioreactor enhanced by an external power supply and its application, so as to solve the problem of how to avoid the attenuation of electric field efficiency caused by excessive thickening of the biofilm by conveniently replacing the carrier.

[0009] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0010] The present invention provides an aerobic biological reaction device enhanced by an external power supply, comprising a reaction box, a plurality of plug-in limit racks arranged in parallel inside the reaction box, an electrode frame detachably arranged on the plug-in limit racks, a plurality of carbon fiber brushes arranged on the electrode frame, a DC power supply connected to each of the carbon fiber brushes, and an aeration mechanism arranged below the carbon fiber brushes;

[0011] A waste liquid inlet is provided at the bottom of the reaction box, and a liquid outlet is provided at the upper part of the side wall of the reaction box; at least the carbon fiber brushes on adjacent plug-in limit racks are respectively connected to positive and negative electrodes of different types on the DC power supply.

[0012] Furthermore, in this embodiment, a cover is provided on the top of the reaction box, and a plurality of assembly grooves adapted to the electrode frame are opened on the cover to facilitate the rapid replacement of the electrode frame; an air pressure regulating valve is also provided on the cover to ensure the stability of the air pressure in the reaction box.

[0013] Furthermore, in this embodiment, the plug-in limiting frame is a U-shaped plug-in structure that fits the inner wall of the reaction box, and a plug-in groove for limiting the bottom and side wall of the electrode frame is opened in the cross section of the U-shaped plug-in structure.

[0014] Furthermore, in this embodiment, the electrode frame includes a plug-in board that can be inserted into the U-shaped plug-in structure, and a connecting baffle arranged on the top of the plug-in board. A reserved groove for installing a plurality of the carbon fiber brushes is opened in the middle of the plug-in board, and wiring terminals for connecting each of the carbon fiber brushes are provided on the connecting baffle.

[0015] Furthermore, in this embodiment, the aeration mechanism includes an aeration frame arranged below the plug-in limit frame, an aeration pipe arranged on the aeration frame, and an air pump arranged outside the reaction box and connected to the aeration pipe through an air pipe, and aeration micropores are evenly opened on the aeration pipe.

[0016] Furthermore, in this embodiment, a magnetic stirring bar is provided at the inner bottom of the reaction box, and a magnetic stirrer for driving the magnetic stirring bar to rotate and stir is provided at the bottom of the reaction box.

[0017] Furthermore, in this embodiment, the waste liquid inlet is connected to a waste water tank through an inlet pipe, a peristaltic pump is provided on the inlet pipe, and an electromagnetic valve is provided at the connecting end of the inlet pipe and the waste liquid inlet.

[0018] Furthermore, in this embodiment, a liquid level sensor and a pH meter are provided on the reaction box; wherein the pH change rate in the reaction box is monitored in real time by the pH meter to determine the oxidation decomposition rate of the fermentation liquid in the reaction box.

[0019] This embodiment provides an application of an aerobic bioreactor enhanced by an external power supply, wherein dairy wastewater is injected into the reaction box to improve the efficiency of synthesizing PHA from the dairy wastewater fermentation liquid.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] (1) Improve the efficiency of PHA synthesis: By applying direct current, the electron transfer process of microorganisms is accelerated, the oxidative decomposition of substrates and the synthesis of PHA are promoted, and the yield and synthesis rate of PHA are significantly increased.

[0022] (2) Optimizing the microbial growth environment: The micro-electric field formed by direct current can affect the metabolic pathways and growth rates of microorganisms, allowing microorganisms to reach the optimal growth state in a shorter time, which is beneficial to the synthesis of PHA.

[0023] (3) Reduce production costs: By improving the synthesis efficiency and output of PHA, the production costs are reduced, providing a more competitive solution for the production of bioplastics.

[0024] (4) Easy to operate and maintain: The reactor has a simple structure, is easy to operate, and is easy to implement automated control and management, which reduces operating costs and maintenance difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] Figure 1 This is a schematic diagram of the main body of the aerobic bioreactor enhanced by an external power supply of the present invention;

[0027] Figure 2 This is a schematic diagram of the installation of the internal plug-in limit frame of the aerobic biological reaction device with enhanced external power supply of the present invention;

[0028] Figure 3 This is a schematic diagram of the upper electrode frame structure of the aerobic biological reaction device enhanced by an external power supply of the present invention;

[0029] Figure 4 Schematic diagram of the connection relationship between the carbon fiber brush and the electrode in Example 1;

[0030] Figure 5 Schematic diagram of the connection relationship between the carbon fiber brush and the electrode in Example 2.

[0031] Description of reference numerals:

[0032] 1. Reaction chamber; 11. Cover; 111. Assembly slot; 12. Air pressure regulating valve; 2. Magnetic stirrer; 21. Magnetic stirring rod; 3. Plug-in limiter; 31. Plug-in slot; 4. Electrode frame; 41. Carbon fiber brush; 42. Connecting baffle; 43. Wiring terminal; 5. DC power supply; 6. Air pump; 61. Air pipe; 7. Aeration rack; 71. Aeration pipe; 711. Aeration micropores; 8. Peristaltic pump; 81. Solenoid valve; 9. Wastewater tank; 91. Liquid inlet pipe; 10. pH meter. DETAILED DESCRIPTION

[0033] This embodiment discloses an aerobic biological reaction device enhanced by an external power supply, including a reaction box 1, four plug-in limit frames 3 installed in parallel inside the reaction box 1, an electrode frame 4 detachably installed on the plug-in limit frame 3, a plurality of carbon fiber brushes 41 installed on the electrode frame 4, a DC power supply 5 connected to each of the carbon fiber brushes 41, and an aeration mechanism installed below the carbon fiber brushes 41; wherein a waste liquid inlet is provided at the bottom of the reaction box 1, a liquid outlet is provided at the upper part of the side wall of the reaction box 1, and a solenoid valve is installed at the liquid outlet; at least the carbon fiber brushes 41 on adjacent plug-in limit frames 3 are respectively connected to different positive and negative electrodes on the DC power supply 5.

[0034] In this embodiment, the reaction box 1 is made of an organic glass container, wherein the reaction box 1 can be designed to be prismatic or cylindrical.

[0035] In this embodiment, the carbon fiber brush 41 serves as a biofilm carrier. After the carbon fiber brush 41 is energized, a micro-electric field is formed on the surface of the biofilm carrier in the reaction box 1. The micro-electric field can accelerate the electron transfer process of the microorganisms, promote the oxidative decomposition of the substrate and the synthesis of PHA. At the same time, the DC power supply 5 can also affect the metabolic pathway of the microorganisms and increase the yield and purity of PHA. The DC power supply 5 is a DC power supply of 0.3V / 0.6V0.9V / 1.2V.

[0036] refer to Figure 1 An air pressure regulating valve 12 is also installed on the cover 11 to balance the influence of the aeration mechanism on the air pressure in the reaction box 1 .

[0037] In this embodiment, reference Figure 3 A cover 11 is installed on the top of the reaction box 1. A plurality of assembly grooves 111 adapted to the electrode frame 4 are opened on the cover 11 to facilitate the insertion of the electrode frame 4 therein and to limit the connection baffle 42 on the electrode frame 4. When maintenance and replacement are required, the electrode frame 4 can be quickly disassembled as needed.

[0038] refer to Figure 2 The plug-in limiting frame 3 is a U-shaped plug-in structure that fits the inner wall of the reaction box 1, and a plug-in groove 31 for limiting the bottom and side wall of the electrode frame 4 is opened in the cross section of the U-shaped plug-in structure.

[0039] refer to Figure 1 and Figure 3 The electrode frame 4 includes a plug-in board that can be inserted into the U-shaped plug-in structure, a connecting baffle 42 installed on the top of the plug-in board, a reserved groove for installing multiple carbon fiber brushes 41 is opened in the middle of the plug-in board, and a wiring terminal 43 for connecting each of the carbon fiber brushes 41 is installed on the connecting baffle 42.

[0040] refer to Figure 4 As an embodiment, the five carbon fiber brushes 41 installed on the same electrode frame 4 are all connected to the same power supply electrode, and are connected to opposite electrodes of the five carbon fiber brushes 41 on adjacent electrode frames 4, so that the carbon fiber brushes 41 installed on adjacent electrode frames 4 are charged differently, thereby forming a microcurrent environment between the adjacent electrode frames 4.

[0041] refer to Figure 5 As another embodiment, the five carbon fiber brushes 41 installed on the same electrode frame 4 are alternately connected to different power electrodes. At the same time, the five carbon fiber brushes 41 on adjacent electrode frames 4 are also spaced apart and connected to different power electrodes; and each carbon fiber brush 41 arranged in the reaction box 1 is connected to a different electrode from the adjacent carbon fiber brushes 41.

[0042] In this embodiment, reference Figure 2 The aeration mechanism includes an aeration frame 7 installed below the plug-in limit frame 3, an aeration pipe 71 installed on the aeration frame 7, and an air pump 6 installed outside the reaction box 1 and connected to the aeration pipe 71 through an air pipe 61. Aeration micropores 711 are evenly opened on the aeration pipe 71, and aeration is carried out upward through the aeration micropores 711.

[0043] A magnetic stirring bar 21 is installed at the inner bottom of the reaction box 1, and a magnetic stirrer 2 is installed at the bottom of the reaction box 1 to drive the magnetic stirring bar 21 to rotate and stir; wherein the gas pipe 61 is located directly above the magnetic stirring bar.

[0044] refer to Figure 1 The waste liquid inlet is connected to a waste water tank 9 through an inlet pipe 91, and a peristaltic pump 8 is installed on the inlet pipe 91. A solenoid valve 81 is installed at the connecting end of the inlet pipe 91 and the waste liquid inlet, so as to adjust the peristaltic pump 8 according to demand to send the waste water in the waste water tank 9 into the reaction box 1; the liquid level can be observed through the transparent waste water tank 9, and the peristaltic pump 8 can be turned off in time.

[0045] In this embodiment, the reaction chamber 1 is also equipped with a liquid level sensor and a pH meter 10 for detecting the liquid level. The pH meter 10 monitors the rate of change of pH in the reaction chamber 1 in real time to determine the oxidative decomposition rate of the fermentation liquid in the reaction chamber 1. As the carbon fiber brush 41 is used, it accumulates more deposits, which can easily lead to a decrease in its conductivity. The pH meter 10 can detect a significant slowdown in the pH change. This pH change can be used to monitor the product accumulation rate, indirectly reflecting the substrate metabolism efficiency. When the efficiency drops significantly (combined with current data), a prompt is issued to replace the carrier, indicating that the carbon fiber brush 41 needs to be replaced or maintained promptly.

[0046] This embodiment also provides an application of an aerobic bioreactor enhanced by an external power supply, wherein dairy wastewater is injected into the reaction box 1 to improve the efficiency of synthesizing PHA from the dairy wastewater fermentation liquid.

[0047] In this embodiment, as a laboratory experimental equipment, the reaction box 1 can be selected to have a length, width and height of 16 cm, 8 cm and 18 cm respectively (effective volume 2000 mL). The filling material in the reaction box 1 is all carbon brushes, and the carbon brush has a diameter of 6 cm and a length of 15 cm. An aeration stone is placed in the aeration area and connected to a backflow device. At the same time, an air pump 6 is connected as an aeration device, and a gas flow meter is turned on to adjust the aeration amount in real time. The cathode and anode are both connected to the external circuit through the carbon brush handle. The reactor is externally connected to a dual-channel DC regulated power supply as a DC power supply (APS3005S-3D).

[0048] The system uses fermentation broth from dairy wastewater in a sequencing batch upflow process with a hydraulic retention time of 24 hours. The fermentation broth enters the reactor from the bottom up, where the microorganisms in the reactor utilize the high organic matter content to decompose and convert organic acids, promoting the synthesis of PHAs.

[0049] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. An aerobic bioreactor enhanced by an external power supply, characterized by: The invention comprises a reaction box (1), a plurality of plug-in limit frames (3) arranged in parallel inside the reaction box (1), an electrode frame (4) detachably arranged on the plug-in limit frames (3), a plurality of carbon fiber brushes (41) arranged on the electrode frame (4), a DC power supply (5) connected to each of the carbon fiber brushes (41), and an aeration mechanism arranged below the carbon fiber brushes (41); A waste liquid inlet is provided at the bottom of the reaction box (1), and a liquid outlet is provided at the upper portion of the side wall of the reaction box (1); and at least the carbon fiber brushes (41) on adjacent plug-in limit racks (3) are respectively connected to different positive and negative electrodes on the DC power supply (5).

2. The aerobic bioreactor enhanced by an external power supply according to claim 1, characterized in that: A cover (11) is provided on the top of the reaction box (1), and a plurality of assembly grooves (111) adapted to the electrode frame (4) are provided on the cover (11); an air pressure regulating valve (12) is also provided on the cover (11).

3. The aerobic bioreactor enhanced by an external power supply according to claim 2, characterized in that: The plug-in limiting frame (3) is a U-shaped plug-in structure that fits the inner wall of the reaction box (1), and a plug-in groove (31) for limiting the bottom and side wall of the electrode frame (4) is provided in the cross section of the U-shaped plug-in structure.

4. The aerobic bioreactor enhanced by an external power supply according to claim 3, characterized in that: The electrode frame (4) comprises a plug-in board that can be inserted into the U-shaped plug-in structure, and a connecting baffle (42) arranged on the top of the plug-in board. A reserved groove for installing a plurality of carbon fiber brushes (41) is provided in the middle of the plug-in board, and a connection terminal (43) for connecting each of the carbon fiber brushes (41) is provided on the connecting baffle (42).

5. The aerobic bioreactor enhanced by an external power supply according to claim 1, characterized in that: The aeration mechanism comprises an aeration frame (7) arranged below the plug-in limiting frame (3), an aeration pipe (71) arranged on the aeration frame (7), and an air pump (6) arranged outside the reaction box (1) and connected to the aeration pipe (71) via an air delivery pipe (61); aeration micropores (711) are evenly provided on the aeration pipe (71).

6. The aerobic bioreactor enhanced by an external power supply according to any one of claims 1 to 5, characterized in that: A magnetic stirring bar (21) is provided at the inner bottom of the reaction box (1), and a magnetic stirrer (2) for driving the magnetic stirring bar (21) to rotate and stir is provided at the bottom of the reaction box (1).

7. The aerobic bioreactor enhanced by an external power supply according to any one of claims 1 to 5, characterized in that: The waste liquid inlet is connected to a waste water tank (9) through an inlet pipe (91), a peristaltic pump (8) is provided on the inlet pipe (91), and a solenoid valve (81) is provided at the end connecting the inlet pipe (91) and the waste liquid inlet.

8. The aerobic bioreactor enhanced by an external power supply according to any one of claims 1 to 5, characterized in that: The reaction box (1) is also provided with a liquid level sensor and a pH meter (10); wherein the pH change rate in the reaction box (1) is monitored in real time by the pH meter (10) to determine the oxidation decomposition rate of the fermentation liquid in the reaction box (1).

9. An application of an aerobic bioreactor enhanced by an external power supply, the aerobic bioreactor enhanced by an external power supply according to any one of claims 1 to 5, characterized in that: Dairy wastewater is injected into the reaction box (1) to improve the efficiency of synthesizing PHA from the dairy wastewater fermentation liquid.

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