Staged electric field strengthening system for promoting rapid decomposition of agricultural waste aerobic compost and application of staged electric field strengthening system

Abstract

The invention discloses a staged electric field strengthening system for promoting rapid decomposition of agricultural waste aerobic compost and application of the staged electric field strengthening system, and belongs to the technical field of organic compost. The invention solves the problems of slow temperature rise, low highest temperature, uneven decomposition, long composting time, poor composting quality and the like in the existing aerobic composting process. The staged electric field strengthening system comprises an anode stainless steel mesh, a cathode graphite rod electrode group and / or a carbon felt, an adjustable power supply and a wire. The system is used for promoting compost maturity, and the concrete method comprises the steps that agricultural waste is mixed and piled on a stainless steel net to form a pile body, a cathode is arranged on the pile body, alternating current is conducted in the high-temperature stage, direct current is conducted in the cooling stage, the temperature of the pile body is reduced to 45 DEG C or below, and composting is completed. Compared with common compost, the staged electric field strengthening system for promoting decomposition has the advantages that the highest temperature of a compost body is increased by about 10-15 DEG C, and the electric field system is simple, easy to operate and low in cost.

Description

Technical Field

[0001] This invention relates to the field of organic composting technology, and in particular to a staged electric field enhancement system for promoting the rapid aerobic composting of agricultural waste and its application. Background Technology

[0002] Aerobic composting is essentially a complex redox process driven by microorganisms, in which the biotransformation of organic matter is constantly accompanied by the gain, loss, and transfer of electrons. In traditional composting systems, electrons generated by the decomposition of organic matter are often in a relatively static, passive state, waiting to be captured by oxygen. This is a passive electron transfer process, which is inefficient and highly dependent on the diffusion and distribution of oxygen. Due to the inevitable uneven distribution of oxygen within the compost pile, localized hypoxic or anaerobic microenvironments can easily form, preventing the timely consumption of electrons generated by microbial degradation of organic matter. This leads to charge accumulation, which not only inhibits the metabolic activity of microorganisms but also hinders further degradation of organic matter. Currently, electric field-enhanced aerobic composting, as a novel high-temperature composting method, can significantly improve oxygen utilization, stimulate the metabolic activity of electroactive bacteria, and promote the degradation of organic matter and the formation of humus, attracting considerable attention. Electric field-enhanced aerobic composting technology has shown advantages such as rapid heating, short cycle, and good maturity, and has broad application prospects. Although electric field-enhanced aerobic composting is an effective strategy for improving compost maturity... However, electric field-enhanced aerobic composting is still in its early stages. To date, there is no unified standard for the electric fields applied to composting. This results in different cathode and anode materials used to establish the electric field, and different voltage values ​​applied. The configuration of the electric field directly affects the maturation effect of electric field-enhanced aerobic composting. Although existing electric field enhancement technologies can improve compost maturation to some extent, the improvement is still limited, and some enhancement effects are not good, resulting in poor compost quality.

[0003] Therefore, it is necessary to develop a new electric field enhancement technology to improve the composting efficiency and quality of aerobic composting, which is of great significance for promoting the green upgrading of composting technology. Summary of the Invention

[0004] To address the problems of slow temperature rise, low maximum temperature, uneven composting, long composting time, and poor compost quality in the aerobic composting process of agricultural waste, this invention provides a staged electric field enhancement system and its application for promoting rapid composting of agricultural waste in aerobic composting.

[0005] The technical solution of the present invention is as follows: One of the objectives of this invention is to provide a staged electric field enhancement system for promoting rapid aerobic composting of agricultural waste. The system includes an anode, a cathode, an adjustable power supply, and wires. The cathode is one or more of graphite rods, graphite rod electrode groups, and carbon felt. The anode is a stainless steel mesh, and the adjustable power supply provides alternating current or direct current.

[0006] Furthermore, in the phased electric field enhancement system, the anode, cathode, and adjustable power supply are connected by wires to form a closed circuit during use.

[0007] Further specifying, the graphite rod electrode assembly consists of at least two graphite rods arranged at equal intervals along a straight line.

[0008] Further specified, the graphite rod and the graphite rod electrode assembly have a height of 2m and a diameter of 70mm.

[0009] Further specified, the voltage of alternating current is 5V and the frequency is 50Hz, and the voltage of direct current is 5V.

[0010] The second objective of this invention is to provide a method for promoting the rapid aerobic composting of agricultural waste using the aforementioned staged electric field enhancement system. This method includes the following steps: Step 1: Mix livestock and poultry manure with crushed corn or rice straw evenly to obtain material. Adjust the carbon-nitrogen ratio (C / N) and moisture content of the material. Place the material on the anode and stack it into a windrow to obtain a pile. Step 2: Install cathodes on the surface and / or inside the stack body, and connect the adjustable power supply, cathode and anode with wires; Step 3, composting: Raise the temperature of the compost pile to above 60℃. Apply alternating current during the high-temperature stage and compost for 15-25 days. Apply direct current during the cooling stage and compost for 15-25 days. Turn the pile every 5 days during the high-temperature stage and once during the cooling stage. When the temperature of the compost pile drops below 45℃, the composting is complete.

[0011] Further specifying, in step one, the C / N ratio is 20-30, and the moisture content is 60-70%.

[0012] Further specifying, in step one, the base width of the pile is 1-4m, the height is 1-2m, and the length is at least 2m; Further specifying, in step two, the cathode is set up by laying carbon felt on the surface of the stack.

[0013] Further specifying, in step two, the cathode is set up by inserting a graphite rod or graphite rod electrode assembly perpendicular to the ground into the bottom of the stack and connecting it to the anode.

[0014] Further specifying, in step two, the cathode setup involves first inserting a graphite rod or graphite rod electrode assembly vertically into the bottom of the stack and connecting it to the anode, and then laying a carbon felt on the surface of the stack, with the carbon felt in contact with the graphite rod or graphite rod electrode assembly.

[0015] Further specifying, the temperature in the high-temperature stage of step three is 60-90℃.

[0016] Further restrictions are imposed: during the composting process in step three, the temperature of the compost pile should not exceed 90°C. If the temperature exceeds 90°C, the pile should be turned over to lower the temperature.

[0017] To further specify, the turning method involves turning the outer and bottom layers of the pile into the center of the pile, and turning the center layer of the pile back to the outer layer, so that the entire pile is fully decomposed.

[0018] The beneficial effects of this invention are as follows: (1) This invention utilizes a staged electric field enhancement technology combining alternating current (AC) and direct current (DC) fields to promote rapid maturation and heating of agricultural waste through aerobic composting. AC is applied during the high-temperature stage of composting, while DC is applied during the cooling and maturation stage. This increases the maximum temperature of the compost pile and solves the problems of uneven maturation and long composting time. Compared to ordinary composting, the composite system of this invention significantly increases the maximum temperature of the compost pile by approximately 10-15°C.

[0019] (2) The phased electric field enhancement system of the present invention has a simple structure and is flexible in its application to promote aerobic composting. The electrodes can be selected according to the size of the compost pile and the actual scenario, which avoids the limitation of application scenarios caused by the need to use containers of fixed size for traditional current-enhanced aerobic composting. The composting method of the present invention is easy to operate and low in cost, thereby solving the problems of low pile temperature, uneven composting and long composting time during the composting process.

[0020] (3) Traditional composting increases the temperature of the compost pile by adding thermophilic bacteria to shorten the composting time and promote decomposition. Each composting operation requires the addition of thermophilic bacteria to the material, and the bacteria need to be activated in advance. This results in problems such as difficulty in determining the amount to be added, high technical difficulty, and high composting cost. The present invention can effectively avoid the above problems. The present invention uses alternating current (AC) in the high-temperature composting stage. Under the action of the AC electric field, the pile will promote the transfer of electrons to oxygen, which can significantly improve the oxygen utilization rate, increase the aerobic respiration of microorganisms, and release more heat, thereby achieving ultra-high temperature composting. However, the temperature provided by AC is high. If AC is used throughout the entire composting process, it will cause the pile to lose moisture rapidly and in large quantities, which is not conducive to the decomposition of aerobic compost. Therefore, the present invention changes AC to DC in the cooling stage. This invention overcomes the limitations of thermophilic bacteria agents in ultra-high temperature composting, offering low cost, speed, and convenience. It enables on-site composting of waste, reducing costs and achieving efficient resource utilization. It can be used in small-scale breeding and family farms that combine planting and animal husbandry, meeting the demand for high-quality organic fertilizer made from agricultural and rural waste such as livestock and poultry manure and crop straw. It also solves the challenges of low-cost and efficient composting in extremely cold climates.

[0021] (4) In this invention, carbon felt is laid on the compost pile. Carbon felt has excellent conductivity and tensile strength. By increasing the contact area between the surface of the compost pile and the carbon felt, which serves as the cathode, the conductivity of the compost pile is improved. At the same time, when an alternating electric field acts on the compost pile to generate high temperature and cause moisture to turn into water vapor, the presence of carbon felt effectively prevents the rapid dissipation of this water vapor. In addition, water vapor partially condenses due to heat exchange with the relatively cool carbon felt and the external environment, forming tiny droplets that adhere to the inner surface of the carbon felt. When ammonia gas produced during the composting process volatilizes and dissipates, it dissolves in the droplets. Therefore, carbon felt can also reduce the volatilization of ammonia gas during composting and retain the nitrogen content of organic fertilizer. Attached Figure Description

[0022] Figure 1 This is a structural schematic diagram of the composting process in Embodiment 1 of the present invention. 1 is an adjustable power supply, 2 is a wire, 3 is carbon felt, 4 is the compost pile, and 5 is a stainless steel mesh. Figure 2 This is a structural schematic diagram of the composting process in Embodiment 2 of the present invention. 1 is an adjustable power supply, 2 is a wire, 3 is a graphite rod, 4 is the compost pile, and 5 is a stainless steel mesh. Figure 3 This is a schematic diagram of the composting process in Embodiment 3 of the present invention. 1 is an adjustable power supply, 2 is a wire, 3 is a graphite rod, 4 is carbon felt, 5 is the compost pile, and 6 is a stainless steel mesh. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0024] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0026] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0027] Example 1 In this embodiment, the cathode of the composite electric field system is a carbon felt, the anode is a stainless steel mesh, and the adjustable power supply can provide AC or DC power. The power supply is connected to the stainless steel mesh and the carbon felt by wires.

[0028] The schematic diagram of the structure formed by using a composite electric field system to promote the rapid aerobic composting of agricultural waste in this embodiment is shown below. Figure 1 As shown, the specific method is as follows: (1) Mix fresh cow dung and crushed corn stalks evenly at a dry weight ratio of 1:2.69, adjust the C / N ratio of the material to 25, and adjust the moisture content to 65%. Place the material on a cathode stainless steel mesh (6mm aperture, 1.0mm wire diameter) and pile it up as shown. Figure 1 The illustrated windrow type, i.e., the stack, has a base width of 1m, a height of 1m, a length of 2m, and a total material volume of 1m³. 3 ; (2) The carbon felt is laid on the surface of the pile body as the cathode of the composite electric field system, and the stainless steel mesh is the anode. The adjustable power supply, stainless steel mesh and carbon felt are connected by wires. (3) Composting process: When the air temperature is 25℃, use 5V, 50HZ AC power to raise the temperature of the pile to above 60℃ within 3-6 hours. This process is completed within 1-2 days. Insert a glass thermometer vertically into the pile to a depth of 25cm to test the pile temperature. When the temperature rises to 60℃, it enters a 22-day high-temperature stage. The temperature during the high-temperature stage is maintained at 60-90℃. Turn the pile once every 5 days. During the high-temperature period, AC power is applied with a voltage of 5V, 50HZ. After the high-temperature stage ends, a 20-day cooling stage begins. During the cooling and composting period, DC power is applied with a voltage of 5V. Turn the pile once during the cooling stage. Control the temperature not to exceed 90℃ throughout the composting process. If the temperature exceeds 90℃, turn the pile immediately to lower the temperature. When turning the pile, turn the outer and bottom materials into the center and the center materials into the outer to promote the complete composting of the pile. When the pile temperature drops below 45℃, the composting is completed.

[0029] In this embodiment, the composting process is completed in 42 days. The compost pile is fully decomposed, turning brownish-red, with a loose granular structure, no odor or ammonia smell, and does not breed flies or insects. After the compost material is fully decomposed, it is crushed to obtain organic fertilizer.

[0030] Example 2 In this embodiment, the cathode of the composite electric field system is a graphite rod, and the anode is a stainless steel mesh. An adjustable power supply can provide either alternating current or direct current. This power supply is connected to the stainless steel mesh and the graphite rod via wires. The graphite rod has a density of 1.8 g / cm³. 3 .

[0031] The schematic diagram of the structure formed by using a composite electric field system to promote the rapid aerobic composting of agricultural waste in this embodiment is shown below. Figure 2 As shown, the specific method is as follows: (1) Mix fresh cow dung and crushed corn stalks evenly at a dry weight ratio of 1:2.69, adjust the C / N ratio of the material to 25, and adjust the moisture content to 65%. Place the material on a cathode stainless steel mesh (6mm aperture, 1.0mm wire diameter) and stack it into a trapezoidal windrow, i.e., a pile. The pile has a base width of 1m, a height of 1m, a length of 2m, and a total material volume of 1m³. 3 ; (2) Insert the graphite rod vertically into the bottom of the pile and connect it with the stainless steel mesh as the cathode of the composite electric field system. The stainless steel mesh is the anode. Connect the adjustable power supply, the stainless steel mesh and the graphite rod with wires. (3) Composting process: When the air temperature is 25℃, use 5V, 50HZ AC power to raise the temperature of the pile to above 60℃ in 3-6 hours. This process is completed in 1-2 days. Insert a glass thermometer vertically into the pile to a depth of 25cm to test the temperature of the pile. When the temperature rises to 60℃, it enters a 22-day high-temperature stage. The temperature of the high-temperature stage is 60-90℃. Turn the pile once every 5 days. During the high-temperature stage, AC power is applied with a voltage of 5V, 50HZ. After the high-temperature stage ends, a 20-day cooling stage begins. During the cooling and composting stage, DC power is applied with a voltage of 5V. Turn the pile once during the cooling stage. Control the temperature not to exceed 90℃ throughout the composting process. If the temperature exceeds 90℃, turn the pile immediately to lower the temperature. When turning the pile, turn the outer and bottom materials into the center and the center materials into the outer to promote the complete composting of the pile. When the temperature of the pile drops below 45℃, the composting is completed.

[0032] In this embodiment, the composting process is completed in 42 days. The compost pile is fully decomposed, turning brownish-red, with a loose granular structure, no odor or ammonia smell, and does not breed flies or insects. After the compost material is fully decomposed, it is crushed to obtain organic fertilizer.

[0033] Example 3 In this embodiment, the cathode of the composite electric field system is a carbon felt and a graphite rod, and the anode is a stainless steel mesh. An adjustable power supply can provide either alternating current or direct current. This power supply is connected to the stainless steel mesh and the graphite rod via wires. The graphite rod has a density of 1.8 g / cm³. 3 .

[0034] The specific method for promoting rapid aerobic composting of agricultural waste using a composite electric field system in this embodiment is as follows: (2) Mix fresh cow dung and crushed corn stalks evenly at a dry weight ratio of 1:2.69, adjust the C / N ratio of the material to 25, and adjust the moisture content to 65%. Place the material on a cathode stainless steel mesh (6mm aperture, 1.0mm wire diameter) and stack it into a trapezoidal windrow, i.e., a pile. The pile has a base width of 1m, a height of 1m, a length of 2m, and a total material volume of 1m³. 3 ; (2) Lay carbon felt on the surface of the pile body, and then insert graphite rods vertically into the bottom of the pile body and connect them with stainless steel mesh. Cut a circular hole with the same diameter as the graphite rod in the center of the carbon felt. Pass the carbon felt through the graphite rod and lay it on the surface of the pile body. The carbon felt and the graphite rod are in contact and together serve as the cathode of the composite electric field system. The stainless steel mesh is the anode. Connect the adjustable power supply, the stainless steel mesh cage and the graphite rod with wires. (3) Composting process: When the air temperature is 25℃, use 5V, 50HZ AC power to raise the temperature of the pile to above 60℃ in 3-6 hours. This process is completed in 1-2 days. Insert a glass thermometer vertically into the pile to a depth of 25cm to test the temperature of the pile. When the temperature rises to 60℃, it enters a 22-day high-temperature stage. The temperature of the high-temperature stage is 60-90℃. Turn the pile once every 5 days. During the high-temperature stage, AC power is applied with a voltage of 5V, 50HZ. After the high-temperature stage ends, a 20-day cooling stage begins. During the cooling and composting stage, DC power is applied with a voltage of 5V. Turn the pile once during the cooling stage. Control the temperature not to exceed 90℃ throughout the composting process. If the temperature exceeds 90℃, turn the pile immediately to lower the temperature. When turning the pile, turn the outer and bottom materials into the center and the center materials into the outer to promote the complete composting of the pile. When the temperature of the pile drops below 45℃, the composting is completed.

[0035] In this embodiment, the composting process is completed in 42 days. The compost pile is fully decomposed, turning brownish-red, with a loose granular structure, no odor or ammonia smell, and does not breed flies or insects. After the compost material is fully decomposed, it is crushed to obtain organic fertilizer.

[0036] Comparative Example 1 The difference between this embodiment and embodiment 2 is that there is no adjustable power source in the composite electric field, no power source is provided during the entire composting process, and no current is supplied. The remaining process steps and parameter settings are the same as in embodiment 2, and the composting time is also 42 days.

[0037] Testing and Experiment Basic physicochemical properties of the organic fertilizers from Examples 1-3 and Comparative Example 1 were tested, and the test results are shown in Table 1. Table 1. Test results of basic physicochemical properties of organic fertilizers in Examples 1-3 and Comparative Example 1

[0038] Note: EC is electrical conductivity, TOC is total organic carbon, and TN is total nitrogen.

[0039] As can be seen from the results in Table 1, the present invention can increase the maximum temperature of the compost pile by about 10-15°C and prolong the duration of high temperature in the compost pile. In Example 2, the C / N ratio of the material was lower at the end of composting. The lower C / N ratio indicates less nitrogen loss during composting. Furthermore, the TN of Examples 1-3 were all higher than that of the comparative example, further illustrating that the present invention results in less nitrogen loss during composting.

[0040] In summary, the composite electric field configuration and method designed in this invention for promoting rapid aerobic composting of agricultural waste have significant advantages in increasing the temperature of the compost pile, extending the high-temperature period, and promoting composting during the composting process.

[0041] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A staged electric field enhancement system for promoting rapid aerobic composting of agricultural waste, characterized in that, The system includes an anode, a cathode, an adjustable power supply, and wires; The cathode is one or more of graphite rod, graphite rod electrode assembly, and carbon felt, and the anode is stainless steel mesh; The adjustable power supply provides either AC or DC power.

2. The staged electric field enhancement system according to claim 1, characterized in that, The graphite rod electrode assembly consists of at least two graphite rods arranged at equal intervals along a straight line.

3. The staged electric field enhancement system according to claim 1, characterized in that, The graphite rod is 2m high and 70mm in diameter.

4. The staged electric field enhancement system according to claim 1, characterized in that, Alternating current has a voltage of 5V and a frequency of 50Hz, while direct current has a voltage of 5V.

5. A method for promoting rapid aerobic composting of agricultural waste using the staged electric field enhancement system according to any one of claims 1-4, characterized in that, The method includes the following steps: Step 1: Mix livestock and poultry manure with crushed corn or rice straw evenly to obtain material. Adjust the carbon-nitrogen ratio and moisture content of the material, place the material on the anode, and stack it into a windrow to obtain a pile. Step 2: Install cathodes on the surface and / or inside the stack body, and connect the adjustable power supply, cathode and anode with wires; Step 3, composting: Raise the temperature of the compost pile to above 60℃. Apply alternating current during the high-temperature stage and compost for 15-25 days. Apply direct current during the cooling stage and compost for 15-25 days. Turn the pile every 5 days during the high-temperature stage and once during the cooling stage. When the temperature of the compost pile drops below 45℃, the composting is complete.

6. The method according to claim 5, characterized in that, In step one, the carbon-to-nitrogen ratio is 20-30, the water content is 60-70%, the base width of the pile is 1-4m, the height is 1-2m, and the length is at least 2m.

7. The method according to claim 5, characterized in that, In step two, the cathode is set up by laying carbon felt on the surface of the stack.

8. The method according to claim 5, characterized in that, In step two, the cathode is set up by inserting a graphite rod or graphite rod electrode assembly perpendicular to the ground into the bottom of the stack and connecting it to the anode.

9. The method according to claim 5, characterized in that, In step two, the cathode setup involves first inserting a graphite rod or graphite rod electrode assembly vertically into the bottom of the stack and connecting it to the anode. Then, carbon felt is laid on the surface of the stack, with the carbon felt in contact with the graphite rod or graphite rod electrode assembly.

10. The method according to claim 5, characterized in that, The high-temperature stage in step three has a temperature of 60-90℃.

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