Method for enhancing compost detoxification effect by using microbial fuel cell
By using microbial fuel cells to accelerate the movement of free electronics in the compost system, the problem of low free electron transfer rate in the conventional compost system has been solved, and the degree of oreization and humusization of organic matter is improved, and heavy metal passivation and antibiotic degradation are achieved. High efficiency, while reducing the construction cost of compost devices.
Patent Information
- Application Number
- CN202411574267.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2025-01-28
AI Technical Summary
The low free electron transfer rate in conventional composting systems limits the mineralization and humification process of organic matter, which in turn affects the efficiency of heavy metal passivation and antibiotic degradation.
The microbial fuel cell is used instead of the exogenous electric field. The conductive board is used as the cathode and anode to accelerate the movement of free electronics, improve the oxygen utilization and microbial activity, thereby promoting the mineralization and humus of organic matter.
It has improved the mineralization rate of organic matter and the degree of humusization, produces organic fertilizer with higher rotten maturity and stronger stability, and effectively reduces the content of heavy metals and antibiotics, and reduces the construction cost of compost devices.
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Figure CN119371237A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for strengthening the detoxification effect of composting. Background Art
[0002] In recent years, the annual output of livestock and poultry manure in my country has exceeded 3 billion tons. Improper treatment has caused a series of environmental problems, such as soil pollution, water quality deterioration, odor emissions, and even endangers human health. Aerobic composting (AC) is a key way to achieve harmless treatment and resource utilization of livestock and poultry manure. It refers to the process of using aerobic microorganisms to promote the decomposition of organic matter in livestock and poultry manure and form stable humus. However, heavy metals and antibiotics in livestock and poultry manure limit its agricultural application as organic fertilizer. Feed often contains heavy metal elements such as zinc and copper, which cannot be completely metabolized by animals and are excreted with feces, seriously affecting crop growth and food security. In addition, antibiotics are an important means of preventing diseases and promoting growth. Their residues will affect the structure and function of microbial communities and accelerate the spread of drug-resistant genes. Therefore, in order to achieve sustainable resource utilization of livestock and poultry manure, we should focus on the research and development of heavy metal passivation and antibiotic degradation technologies to ensure the efficient production and safe application of organic fertilizers.
[0003] During aerobic composting, organic matter is decomposed into small molecular organic acids by microorganisms and functional enzymes. These organic acids can adsorb free metal ions through their own functional groups and eventually form a stable humus matrix. At the same time, the heat released by the decomposition of organic matter can accelerate the volatilization and degradation of antibiotics. Therefore, the mineralization and humification of organic matter are key control factors for the passivation of heavy metals and the degradation of antibiotics. However, the poor conductivity of composting materials hinders the movement of free electrons released by the decomposition of organic matter, thereby reducing the utilization rate of oxygen and the degree of mineralization and humification of organic matter. At present, studies have used electric field-assisted composting (EFC) to accelerate the movement of free electrons, promote the mineralization and humification of organic matter by improving the utilization rate of oxygen, and indirectly improve the detoxification effect of heavy metals and antibiotics. However, electric field-assisted composting requires additional power, which increases the economic cost of composting. Summary of the invention
[0004] In order to solve the problem that the free electron transfer rate in conventional composting systems is low and thus limits the mineralization and humification processes of organic matter, the present invention provides a method for enhancing the detoxification effect of composting by using microbial fuel cells.
[0005] The method of enhancing the detoxification effect of composting by using a microbial fuel cell of the present invention is carried out according to the following steps:
[0006] 1. Mix fresh pig manure and rice straw to obtain compost raw materials;
[0007] 2. Selecting conductive plates as cathode and anode of the microbial fuel cell;
[0008] 3. Add the compost obtained in step 1 to the fermentation barrel with a thickness of 15 to 25 cm, and lay the cathode on the surface of the compost; continue to add the compost obtained in step 1 until the compost is 30 cm away from the top of the fermentation barrel, and lay the anode on the surface of the compost; finally, fill the fermentation barrel with the remaining compost in step 1; use a DC standard resistance box as an external source resistance, and connect the cathode and anode in the fermentation barrel to the positive and negative poles of the resistance box with wires respectively;
[0009] 4. Carry out aerobic fermentation in the fermentation barrel under ventilation conditions, turn the fermentation barrel over every 2 days. After 8 to 12 days, turn the fermentation barrel over every 5 days until the compost raw materials reach the maturity standard, which means that the detoxification of the compost raw materials is completed.
[0010] Beneficial effects of the present invention:
[0011] The present invention adopts microbial fuel cells instead of external electric fields, which can not only reduce the construction cost of the composting device, but also simplify the composting operation process. It has the advantages of low cost, easy operation and high efficiency, and is more beneficial to the promotion and application of aerobic composting technology.
[0012] The microbial fuel cell-assisted composting process constructed by the present invention solves the problem of slow free electron transfer rate in conventional composting systems. The present invention indirectly improves the mineralization rate and humification degree of organic matter by improving the utilization rate of oxygen and the activity of microorganisms, and can produce organic fertilizers with higher maturity and stronger stability.
[0013] The microbial fuel cell-assisted composting process constructed by the present invention achieves the purpose of reducing the toxicity of heavy metals by adsorbing heavy metal ions with small molecule organic acids to form a humus matrix. At the same time, by increasing the activity of microorganisms and promoting the decomposition of organic matter, the volatilization and degradation of antibiotics in the high temperature period are accelerated, thereby reducing the content of antibiotics in organic fertilizers. The microbial fuel cell-assisted composting process constructed by the present invention has a high detoxification effect.
[0014] The present invention utilizes microbial fuel cells to accelerate the movement of free electrons, thereby solving the problem of low free electron transfer rate in conventional composting systems that limits the mineralization and humification processes of organic matter. The present invention can not only achieve the purpose of reducing heavy metal toxicity and antibiotic content, but also reduce the construction cost of the composting device, and is more conducive to the promotion and application of aerobic composting technology. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 This is a diagram of the microbial fuel cell assisted composting device in Example 1;
[0016] Figure 2 The dynamic changes of heavy metal content and bioavailability during the composting process in Example 1;
[0017] Figure 3 The figure shows the dynamic changes of antibiotic content during the composting process in Example 1. DETAILED DESCRIPTION
[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0019] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.
[0020] Specific implementation method 1: The method of using microbial fuel cells to enhance the detoxification effect of composting in this implementation method is carried out according to the following steps:
[0021] 1. Mix fresh pig manure and rice straw to obtain compost raw materials;
[0022] 2. Selecting conductive plates as cathode and anode of the microbial fuel cell;
[0023] 3. Add the compost obtained in step 1 to the fermentation barrel with a thickness of 15 to 25 cm, and lay the cathode on the surface of the compost; continue to add the compost obtained in step 1 until the compost is 30 cm away from the top of the fermentation barrel, and lay the anode on the surface of the compost; finally, fill the fermentation barrel with the remaining compost in step 1; use a DC standard resistance box as an external source resistance, and connect the cathode and anode in the fermentation barrel to the positive and negative poles of the resistance box with wires respectively;
[0024] 4. Carry out aerobic fermentation in the fermentation barrel under ventilation conditions, turn the fermentation barrel over every 2 days. After 8 to 12 days, turn the fermentation barrel over every 5 days until the compost raw materials reach the maturity standard, which means that the detoxification of the compost raw materials is completed.
[0025] In step 1 of this embodiment, the rice straw is naturally air-dried and the length of the straw is 1 to 2 cm.
[0026] The fermentation barrel used in step three of this embodiment is a polyethylene plastic barrel with a volume of 100L, and its specifications are: upper diameter 500mm, lower diameter 400mm, and height 620mm.
[0027] In step three of this embodiment, three anode and cathode plates are laid.
[0028] The DC standard resistor box selected in step 3 of this embodiment is DoMore ZX21, and the overall precision level is 0.05%; the resistance value of the external resistor in step 3 is set to 1Ω to ensure the formation of electron flow in the composting system and the detection of electrical parameters.
[0029] In step 4 of this embodiment, the compost turning is to transfer all the mixed materials out of the fermentation barrel and mix the materials with different fermentation degrees evenly again; then, the microbial fuel cell composting device is reassembled according to step 3.
[0030] In step 4 of this embodiment, the method for judging whether the compost material has reached the maturity standard is that the temperature of the pile is close to room temperature and there is no obvious temperature rise after the material is turned over; the time for the compost material of pig manure and straw to reach the maturity standard is about 30 days.
[0031] This embodiment uses a microbial fuel cell instead of an external electric field, which can not only reduce the construction cost of the composting device, but also simplify the composting operation process. It has the advantages of low cost, easy operation and high efficiency, and is more beneficial to the promotion and application of aerobic composting technology.
[0032] The microbial fuel cell-assisted composting process constructed in this embodiment solves the problem of slow free electron transfer rate in conventional composting systems. The process indirectly improves the mineralization rate and humification degree of organic matter by improving the utilization rate of oxygen and the activity of microorganisms, and can produce organic fertilizers with higher maturity and greater stability.
[0033] The microbial fuel cell-assisted composting process constructed in this embodiment achieves the purpose of reducing the toxicity of heavy metals by adsorbing heavy metal ions with small molecule organic acids to form a humus matrix. At the same time, by increasing microbial activity and promoting the decomposition of organic matter, the volatilization and degradation of antibiotics during the high temperature period are accelerated, thereby reducing the content of antibiotics in organic fertilizers.
[0034] Specific implementation method 2: This implementation method is different from specific implementation method 1 in that the mixing volume ratio of pig manure to rice straw in step 1 is 1:3-5, and the moisture content of the mixed material is adjusted to about 60% with ultrapure water. Other steps and parameters are the same as those in specific implementation method 1.
[0035] The mixing volume ratio of pig manure to rice straw in this embodiment is 1:3-5 in order to maintain the initial carbon-nitrogen ratio (C:N) of the mixture within the range of 22-28.
[0036] Specific implementation method 3: This implementation method is different from specific implementation method 1 in that the conductive plate selected in step 2 is galvanized copper, and the conductor material is copper wire wrapped with insulating glue. Other steps and parameters are the same as those in specific implementation method 1.
[0037] The cathode and anode of the conductive plate in this embodiment are made of the same material, both galvanized copper; no primary battery is involved, and the electrode plate only serves to conduct electricity and accelerate the movement of electrons.
[0038] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the conductive plate in step 2 is a galvanized copper ring plate with a diameter of 10 cm, and the diameter of the copper wire in the conductor is 2 mm. Other steps and parameters are the same as those of specific embodiments 1 to 3.
[0039] Embodiment 1 The method of using microbial fuel cells to enhance the detoxification effect of composting in this embodiment includes the following steps:
[0040] 1. Select fresh pig manure and rice straw as compost raw materials; air-dry the straw naturally and crush it for later use; then, mix the pig manure and straw evenly, and adjust the moisture content of the mixture to about 60% with ultrapure water;
[0041] 2. Select the conductive plates as the cathode and anode of the microbial fuel cell, and connect the cathode and anode to the wires;
[0042] 3. Add the compost obtained in step 1 to the fermentation barrel with a thickness of 15 to 25 cm, and lay the cathode on the surface of the compost; continue to add the compost obtained in step 1 until the compost is 30 cm away from the top of the fermentation barrel, and lay the anode on the surface of the compost; finally, fill the fermentation barrel with the remaining compost in step 1; use a DC standard resistance box as an external source resistance, and connect the cathode and anode in the fermentation barrel to the positive and negative poles of the resistance box with wires respectively;
[0043] Fourth, the microbial fuel cell assisted composting device obtained in steps one, two and three is placed in a ventilated place for aerobic fermentation. During this period, the compost is turned manually every two days for the first 10 days; thereafter, the compost is turned manually every five days until the mixed material reaches the maturity standard, thus completing the detoxification of the compost raw materials.
[0044] Furthermore, in step 1, the length of the straw crushed is 1 to 2 cm to ensure the ventilation and heat preservation of the pile.
[0045] Furthermore, in step 1, the mixing volume ratio of pig manure to straw is 1:4, so that the initial carbon-nitrogen ratio (C:N) of the mixture is maintained in the range of 22-28.
[0046] Furthermore, the conductive plate material selected in step 2 is galvanized copper, and the conductor material is copper wire wrapped with insulating glue.
[0047] Furthermore, the conductive plate selected in step 2 is a galvanized copper ring plate with a diameter of 10 cm, and the diameter of the copper wire in the conductor is 2 mm.
[0048] Furthermore, the fermentation barrel used in step three is a polyethylene plastic barrel with a volume of 100L, and its specifications are: upper diameter 500mm, lower diameter 400mm, and height 620mm.
[0049] Furthermore, the number of cathode and anode plates laid in step three is 3.
[0050] Furthermore, the brand of the DC standard resistance box selected in step 4 is DoMore ZX21, and the overall precision level is 0.05%.
[0051] Furthermore, in step 4, the resistance of the external resistor is set to 1Ω to ensure the formation of the electron flow of the composting system and the detection of the electrical parameters.
[0052] Furthermore, in step 5, turning the compost is to transfer all the mixed materials out of the fermentation barrel and mix the materials with different fermentation degrees evenly again; then, reassemble the microbial fuel cell composting device according to steps 3 and 4, and continue aerobic fermentation in a ventilated place.
[0053] Furthermore, in step five, the method for judging whether the compost material has reached the maturity standard is that the temperature of the pile is close to the room temperature and there is no obvious temperature rise after the material is turned over.
[0054] Furthermore, in step five, the time it takes for the mixture of pig manure and straw to reach the maturity standard is about 30 days.
[0055] The formula for calculating the metal bioavailability in this embodiment is: metal bioavailability = (exchangeable state + reducible state) / total amount.
[0056] Figure 1 This is a diagram of a microbial fuel cell assisted composting device in this embodiment. The detoxification effect of heavy metals and antibiotics in the embodiment is evaluated as follows:
[0057] The experimental results are as follows Figure 2 and 3 As shown, Figure 2 The dynamic changes of heavy metal content and bioavailability during the composting process of this example; Figure 3 The figure shows the dynamic changes of antibiotic content during the composting process of this embodiment. Figure 2 and Figure 3 middle Indicates conventional composting, It shows that after 30 days of fermentation, the bioavailability of zinc (Zn) and copper (Cu) in the microbial fuel cell composting treatment was reduced by 7.8% and 26.9% respectively, and the content of tetracycline (Tetracycline) and oxytetracycline (Oxytetracycline) was reduced by 100% and 89% respectively compared with the conventional composting treatment. This is because microbial fuel cells can accelerate the movement rate of free electrons in the composting system, indirectly improve the activity of microorganisms and the utilization rate of oxygen, and then promote the mineralization and humification process of organic matter. The energy released by the decomposition of organic matter promotes the volatilization and degradation of antibiotics; at the same time, the small molecular organic acids released by the decomposition of organic matter can adsorb free heavy metal ions through functional groups, and form a stable humus matrix through the humification process. It can be seen that microbial fuel cells solve the problem of low free electron movement rate in conventional composting systems, and achieve the purpose of passivating heavy metals and degrading antibiotics by improving the mineralization and humification of organic matter.
Claims
1. A method for enhancing the detoxification effect of composting using a microbial fuel cell, characterized in that The method of enhancing the detoxification effect of composting by using microbial fuel cells is carried out in the following steps:
1. Mix fresh pig manure and rice straw to obtain compost raw materials; 2. Selecting conductive plates as cathode and anode of the microbial fuel cell; 3. Add the compost obtained in step 1 to the fermentation barrel with a thickness of 15 to 25 cm, and lay the cathode on the surface of the compost; continue to add the compost obtained in step 1 until the compost is 30 cm away from the top of the fermentation barrel, and lay the anode on the surface of the compost; finally, fill the fermentation barrel with the remaining compost in step 1; use a DC standard resistance box as an external source resistance, and connect the cathode and anode in the fermentation barrel to the positive and negative poles of the resistance box with wires respectively; 4. Carry out aerobic fermentation in the fermentation barrel under ventilation conditions, turn the fermentation barrel over every 2 days. After 8 to 12 days, turn the fermentation barrel over every 5 days until the compost raw materials reach the maturity standard, which means that the detoxification of the compost raw materials is completed.
2. The method of claim 1, wherein the method comprises: In step 1, the mixing volume ratio of pig manure to rice straw is 1:3-5, and the moisture content of the mixed material is adjusted to about 60% with ultrapure water.
3. The method of enhancing the detoxification effect of composting by using a microbial fuel cell according to claim 1, characterized in that The conductive plate selected in step 2 is galvanized copper, and the conductor is a copper wire wrapped with insulating glue.
4. The method of enhancing the detoxification effect of composting by using a microbial fuel cell according to claim 3, characterized in that In step 2, the conductive plate is a galvanized copper ring plate with a diameter of 10 cm, and the diameter of the copper wire in the conductor is 2 mm.