Composting fermentation method and device for organic waste

Abstract

The invention discloses a composting fermentation method and device for organic waste, belonging to the technical field of composting. The method firstly utilizes natural microorganisms in organic waste to carry out acidification fermentation under anaerobic conditions, hydrolyzes and acidifies the organic waste to generate organic acid in a short period of time, obtains acidified materials, and then mixes the acidified materials with original organic waste for aerobic composting fermentation. The acidified materials obtained by the acidification fermentation of the organic waste itself are used to effectively adjust the pH value of the composting materials, without adding exogenous pH regulators, and without causing damage to microorganisms or bacterial agents in the materials, thereby improving the utilization rate of organic waste and reducing the production cost of composting products. Moreover, the addition of the acidified materials makes the composting process have the advantages of fast heating, high temperature peak value in the high temperature period, rapid decomposition, high material decomposition degree, etc., thus accelerating the composting process, directly utilizing the high temperature generated when the composting materials are piled up to kill pathogens, insect eggs, etc. in the raw materials, and the composting products have good quality.

Description

Technical Field

[0001] The invention belongs to the technical field of composting, and in particular relates to a composting fermentation method and a device for organic waste. Background Art

[0002] At present, the main raw materials used in the aerobic composting treatment method of organic waste are solid organic waste, such as straw, branches, livestock and poultry manure, food processing waste residues and scraps, etc. Aerobic microorganisms degrade the macromolecular substances in the organic matter under sufficient oxygen conditions, so that they can complete the process of humification, mineralization and harmlessness. The decomposed compost products can be used for subsequent product production. There is usually a problem of high pH of the material in this process, which leads to a high pH value of the compost product. According to the national standard NY / T 525-2021 "Organic Fertilizer", the pH value of organic fertilizer should be in the range of 5.5 to 8.5. The pH value of the compost product is too high, which is not conducive to the production of high-quality organic fertilizer, especially for alkaline soil.

[0003] The current solutions are as follows: First, inorganic strong acids, such as hydrochloric acid, sulfuric acid, nitric acid, etc., are added to the raw materials to forcibly control the pH value of the materials. However, the above strong acids are not only costly, but also highly corrosive, and will have a strong killing effect on microorganisms in the materials, such as natural microorganisms and functional microorganisms in the composting agents. Second, organic acids, such as humic acid, amino acid liquid, etc., are added to the raw materials or products, which are relatively expensive. Third, other acidic raw materials are added to the raw materials. For example, the Chinese invention patent with patent number CN202010043386.X discloses a compost additive containing superacidified biogas slurry, a preparation method and application. The invention uses superacidified biogas slurry produced by failed anaerobic biogas fermentation as the main raw material, and after centrifugation, pasteurization and other treatment steps, enzymes such as catalase, Lactobacillus johnsonii, Lactobacillus rhamnosus, vermiculite and diatomaceous earth, active microorganisms, and porous materials are added to prepare a compost additive. The compost additive is used for composting treatment, and it is disclosed that the superacidified biogas slurry contains volatile fatty acids that can adjust the pH value of the system. However, the superacidified biogas slurry in this scheme is a waste product in biogas production, and its source is not fixed. In addition, the superacidified biogas slurry needs to be pasteurized to remove pathogens, and volatile fatty acids also suffer certain losses due to heating. In addition, the composting time is relatively long, requiring 60 days. All of the above schemes require the introduction of exogenous substances into the raw materials to adjust the pH of the materials, which increases the cost investment and is not conducive to large-scale promotion. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a composting fermentation method of organic waste with low cost.

[0005] The present invention also aims to provide a composting and fermentation device for organic waste.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0007] A composting and fermentation method for organic waste comprises the following steps:

[0008] (1) Biological acidification: the organic waste is crushed and then added to an acidification device for biological hydrolysis and acidification, wherein the carbon-nitrogen ratio of the organic waste is 29 to 32:1, the water content is 90% to 94%, the acidification temperature is 15° C. to 35° C., the acidification time is 4 to 9 days, and the acidification device is kept in a closed state during operation. After the acidification is completed, a solid-liquid mixed acidified material is obtained, and the pH value of the acidified material is 5.0 to 5.5;

[0009] (2) Aerobic composting fermentation: The acidified material obtained in step (1) and the organic waste used to prepare the acidified material are mixed and added into an aerobic composting device as compost material for aerobic composting fermentation. The carbon-nitrogen ratio of the compost material is 25 to 30:1, the water content is 60% to 70%, the initial temperature is 30° C. to 55° C., the composting time is 7 to 20 days, and a compost product is obtained after the fermentation is completed.

[0010] Preferably, in step (1), the carbon-nitrogen ratio of the organic waste is 31:1, the water content is 92%, the acidification temperature is 35°C, and the acidification time is 4 days; in step (2), the carbon-nitrogen ratio of the compost material is 25:1, the water content is 60%, the initial temperature is 35°C, and the composting time is 7 days.

[0011] Preferably, in step (2), during aerobic composting fermentation, a decomposition promoting agent is added to the aerobic composting device, and the decomposition promoting agent is a mixture of bacterial agent, enzyme preparation and biochar.

[0012] Preferably, the bacterial agent accounts for 0.5% to 1.0% of the total mass of the compost material, the enzyme preparation accounts for 0.5% to 1.0% of the total mass of the compost material, and the biochar accounts for 1% to 3% of the total mass of the compost material.

[0013] A composting and fermentation device for organic waste, comprising an acidification device, an aerobic composting device, and a control system. The acidification device is arranged above the aerobic composting device. The acidification device is a closed conical bucket structure. The top of the acidification device is provided with a first feeding port, a second feeding port, and an automatic exhaust valve. The first feeding port is used to add organic waste into the acidification device. The second feeding port is used to add water or nutrient liquid into the acidification device to adjust the water content or carbon-nitrogen ratio of the organic waste. The bottom of the acidification device is provided with an acidification material discharge port, which is connected to the aerobic composting device. An automatic discharge device is provided at the acidification material discharge port. The automatic discharge device controls the opening of the acidification material discharge port according to the gravity of the acidification material to send the acidification material in the acidification device into the aerobic composting device. The aerobic composting device comprises a storage barrel, a gear turntable, a driving motor, and a supporting base. The storage barrel is horizontally arranged on the supporting base. The storage barrel is a hollow structure. One end of the storage barrel An acidification material feed port, a detection port, and an organic waste feed port for organic waste and gas are provided. The organic waste feed and inflation port are connected to an external inflation device. The acidification material feed port of the fermentation cylinder is connected to the acidification material discharge port of the acidification device. The other end of the storage cylinder is provided with a dehumidification port, a compost product discharge port, and a leachate discharge port. An exhaust valve is provided at the dehumidification port. The gear turntable is fixed around the outer wall of the storage cylinder. The driving end of the drive motor is meshed and connected with the gear turntable to drive the storage cylinder to rotate and turn the compost material in the storage cylinder to keep the pile in an aerobic state to promote uniform degradation of organic matter. Heaters are also provided in the acidification device and the fermentation cylinder, respectively. The control system is electrically connected to the heater of the acidification device, the drive motor, the inflation device, the exhaust valve, and the heater of the fermentation cylinder, respectively, so as to control the temperature of the material in the acidification device, the discharge of the acidification material, the rotation speed of the fermentation cylinder, the inflation, the exhaust, and the temperature of the material in the fermentation cylinder.

[0014] Preferably, the automatic discharging device includes a baffle plate and a discharging end pressure sensor. The baffle plate is rotatably connected to the acidified material discharge port. The discharging end pressure sensor is installed on one side of the baffle plate. The discharging end pressure sensor is connected to the control system. The weight of the acidified material in the acidifying device is detected by the discharging end pressure sensor, and the detection signal is transmitted to the control system. The control system controls the opening or closing of the baffle plate according to the signal transmitted by the discharging end pressure sensor.

[0015] Preferably, temperature and humidity sensors are also provided at both ends of the fermentation cylinder, and the control system is electrically connected to the temperature and humidity sensors and receives signals transmitted by the temperature and humidity sensors to control the heater to adjust the initial temperature of the compost material.

[0016] Preferably, a dust and ammonia removal filter is provided at the moisture removal outlet.

[0017] In the composting fermentation method and device for organic waste, organic waste is placed in the composting fermentation device for organic waste, and firstly, acidification fermentation is carried out by using natural microorganisms in the organic waste under anaerobic conditions, so that the organic waste is hydrolyzed and acidified to generate organic acid in a short period of time, and an acidified material with a pH value of 5.0 to 5.5 is obtained, and then the acidified material is mixed with the organic waste for preparing the acidified material and aerobic composting fermentation is carried out as a composting material, and the acidified material obtained by acidification fermentation of the organic waste itself is effectively adjusted to the pH value of the composting material, without adding an exogenous pH regulator, and will not cause damage to the microorganisms or bacterial agents in the material, thereby improving the utilization rate of the organic waste and reducing the production cost of the compost product; in addition, the addition of the acidified material makes the composting process have the advantages of fast heating, high temperature peak value in the high temperature period, rapid decomposition, high material decomposition degree, etc., which accelerates the composting process, and directly uses the high temperature generated when the composting material is piled up to kill pathogens, insect eggs, etc. in the raw materials, and the compost product has good quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the influence of different temperatures on the pH of acid-producing materials.

[0019] Figure 2 is the total ion current of volatile fatty acids.

[0020] Figure 3 It is the volatile fatty acid content.

[0021] Figure 4 It is the effect of different additives on compost temperature.

[0022] Figure 5 The effect of different additives on nitrogen loss (A) and carbon loss (B) in composting.

[0023] Figure 6 The effect of different additives on the germination index of compost seeds.

[0024] Figure 7 It is a structural schematic diagram of a composting and fermentation device for organic waste.

[0025] Figure 8 It is a structural schematic diagram of the acidification unit.

[0026] In the figure: an acidification device 10, a first feeding port 11, a second feeding port 12, an automatic exhaust valve 13, an acidification material discharge port 14, an automatic discharge device 15, a baffle plate 151, a discharge end pressure sensor 152, an aerobic composting device 20, a fermentation cylinder 21, an acidification material feed port 211, an organic waste feed and inflation port 212, a detection port 213, a moisture exhaust port 214, a dust and ammonia removal filter 2141, a compost product discharge port 215, a leachate discharge port 216, a temperature and humidity sensor 217, a gear turntable 22, a support base 23, and a drive motor 24. DETAILED DESCRIPTION

[0027] The technical solutions and technical effects of the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings of the present invention.

[0028] The present invention provides a composting fermentation method for organic waste, comprising the following steps:

[0029] (1) Biological acidification: the organic waste is crushed and then added to an acidification device for biological hydrolysis and acidification, wherein the carbon-nitrogen ratio of the organic waste is 29 to 32:1, the water content is 90% to 94%, the acidification temperature is 15° C. to 35° C., the acidification time is 4 to 9 days, and the acidification device is kept in a closed state during operation. After the acidification is completed, a solid-liquid mixed acidified material is obtained, and the pH value of the acidified material is 5.0 to 5.5;

[0030] The organic waste is any one of livestock and poultry manure, straw, garden waste, agricultural and food industry processing waste, and kitchen waste, or a mixture of two or more thereof. The above-mentioned organic waste is used as acid-producing material, which contains a large amount of organic matter that can be degraded by microorganisms. Under certain moisture, temperature and anaerobic conditions, the following microbial action occurs, thereby reducing the pH value of the material. Specifically, in the first stage, the hydrolytic bacteria in the acid-producing material use the hydrolysis reaction to hydrolyze the macromolecular organic matter into small molecular soluble substances, such as organic acids, ammonia, H 2 , CO 2 In the second stage, the hydrogen-producing and acetogenic bacteria in the acid-producing materials degrade the small molecular alcohols and organic acids produced in the first stage into acetic acid, butyric acid, propionic acid, H 2 , CO 2 The pH value of the material is significantly reduced, and the overall acidity is acidic. The hydrolytic bacteria are facultative anaerobic microorganisms, and the hydrogen-producing and acetic acid-producing bacteria are strictly anaerobic microorganisms and facultative anaerobic microorganisms. Therefore, the acidification device must be kept sealed during operation to prevent external oxygen from entering the device to ensure the acid-producing activity of the microorganisms in the material. The optimal acidification time has a certain correlation with the material composition and ambient temperature. The smaller the molecular weight of the organic matter in the raw material, the easier it is to be degraded by microorganisms. When the ambient temperature is between 15°C and 35°C, the acidification rate is fastest.

[0031] (2) Aerobic composting fermentation: The acidified material obtained in step (1) and the organic waste used to prepare the acidified material are mixed and added into an aerobic composting device as compost material for aerobic composting fermentation. The carbon-nitrogen ratio of the compost material is 25 to 30:1, the water content is 60% to 70%, the initial temperature is 30°C to 55°C, the composting time is 7 to 20 days, and the compost product is obtained after the fermentation is completed. The temperature, humidity and ventilation volume of the compost material can be adjusted by the aerobic composting device. The composting starting temperature is related to the composting fermentation speed. When the composting starting temperature is 30 to 55°C, the organic waste composting fermentation speed is the fastest.

[0032] The present invention utilizes natural microorganisms in organic waste for acidification fermentation, and by regulating the carbon-nitrogen ratio, moisture content, fermentation time and temperature of the material, the organic waste is hydrolyzed and acidified in a short period of time to generate organic acid, and obtain an acidified material with a pH value of 5.0 to 5.5, and then the acidified material is mixed with the original organic waste for aerobic composting fermentation to obtain a compost product. After the organic waste is subjected to the acidification treatment in step (1), many macromolecular organic substances in the organic waste are decomposed into small molecular organic acids, making the acidified material acidic as a whole. After adding the acidifying material, on the one hand, the organic waste can quickly utilize the small molecular organic matter in the acidifying material, and the acidifying material obtained by the acidification and fermentation of the organic waste itself can effectively adjust the pH value of the compost material, without adding an exogenous pH regulator, and will not cause damage to the microorganisms in the material, thereby improving the conversion rate of the organic waste and reducing the production cost of the compost product. In addition, since the raw materials of the acidifying material are the same as those of the aerobic composting, the composting production process is simplified; on the other hand, since most of the functional microorganisms in aerobic composting like a weak acid environment, the acidifying material can provide a suitable environment for the functional microorganisms in aerobic composting, accelerate the metabolism and material conversion of aerobic microorganisms in organic waste, and a large amount of heat will be generated during the metabolism and material conversion of aerobic microorganisms, thereby promoting the aerobic composting process, so that the compost has the advantages of fast heating, high temperature peak value in the high temperature period, rapid decomposition, high material decomposition degree, etc., and directly utilizes the high temperature generated when the composting material is piled up to kill the pathogens, insect eggs, etc. in the raw materials, and the compost product has good quality.

[0033] Specifically, in step (1), the carbon-nitrogen ratio of the organic waste is 31:1, the water content is 92%, the acidification temperature is 35°C, and the acidification time is 4 days; in step (2), the carbon-nitrogen ratio of the compost material is 25:1, the water content is 60%, the initial temperature is 35°C, and the composting time is 7 days.

[0034] Furthermore, in step (2), during aerobic composting fermentation, a decomposition promoting agent is added to the aerobic composting device, and the decomposition promoting agent is a mixture of bacterial agents, enzyme preparations, and biochar.

[0035] Furthermore, the bacterial agent accounts for 0.5% to 1.0% of the total mass of the compost material, the enzyme preparation accounts for 0.5% to 1.0% of the total mass of the compost material, and the biochar accounts for 1.0% to 3.0% of the total mass of the compost material.

[0036] The present invention is described in detail below with reference to specific embodiments.

[0037] The organic waste used in the following examples is a mixture of fresh cow dung and sawdust. The physical and chemical properties of the fresh cow dung and sawdust are shown in Table 1. The C / N ratio is adjusted by the addition amount of the fresh cow dung and sawdust.

[0038] Organic waste can also be made into branch powder, and nitrogen-containing substances can be used to adjust the C / N ratio.

[0039] Table 1 Basic properties of fermentation materials

[0040]

[0041] The bacterial agents used include cellulose-degrading bacteria, lignin-degrading bacteria and other microorganisms that promote the degradation of fiber-like substances.

[0042] The enzyme preparation used contains enzymes such as cellulose degrading enzyme, laccase, pectinase, etc. that promote the degradation of waste.

[0043] The biochar used is prepared at 400-500°C. In the processing of biochar, the higher the temperature, the stronger the alkalinity and the stronger the biological toxicity. The biochar prepared at 400-500°C has lower biological toxicity, which can reduce the toxicity of biochar to composting microorganisms and is beneficial to improving the quality of compost products.

[0044] 1. Biological acidification treatment of materials

[0045] Fresh cow dung and sawdust were mixed as acid-producing raw materials, and their C / N ratios were adjusted to 22:1, 25:1, 28:1, 31:1, and 34:1, respectively. They were placed in sealed fermentation bottles, sterile water was added to make the water content of the acid-producing raw materials reach 92%, and the bottles were sealed with sealing films to prevent air leakage; the fermentation bottles were placed in constant temperature boxes at 15°C, 25°C, and 35°C for anaerobic fermentation, with 3 replicates per treatment. Samples were taken every 24 hours to test the pH value of the fermentation liquid, and a dynamic change curve of the pH value of the fermentation liquid was drawn to clarify the optimal C / N ratio and environmental temperature conditions.

[0046] The results are as follows Figure 1As shown in the figure, the pH value of each treated material shows a pattern of rapid decrease and then slow increase with the anaerobic fermentation time. The C / N ratio of the material is correlated with the change of the pH value of the material. There is an optimal carbon-nitrogen ratio of 31:1. Above or below the optimal carbon-nitrogen ratio, it is not conducive to the acidification of the material. Within the test range, the rate of decrease of the pH value of the material is proportional to the temperature, that is, the higher the temperature, the faster the pH value of the material decreases. When the C / N is 31:1, the acidification peak values ​​reached in the 15℃, 25℃, and 35℃ treatment groups are 5.47, 5.40, and 5.32, respectively, and the required anaerobic fermentation time is 9, 7, and 4 days, respectively. In summary, during biological acidification, when the carbon-nitrogen ratio of organic waste is 31:1, the acidification temperature is 35℃, and the acidification time is 4 days, the pH value of the prepared acidified material is the lowest. In practical production, adjustments can be made according to the properties of the materials and environmental conditions. For example, in early winter or spring, when the ambient temperature is low and the acidification device is not heated, the material acidification time can be extended until the pH value of the material reaches the lowest level.

[0047] 2. Organic acids in acidified materials

[0048] Gas chromatography was used to determine the types and contents of organic acids in the acidified material. The results were as follows: Figure 2 , 3 As shown, 7 volatile fatty acids were detected, and the content was acetic acid, butyric acid, propionic acid, isobutyric acid, caproic acid, isovaleric acid, and valeric acid in descending order. Among them, acetic acid and butyric acid were the main volatile organic acids, indicating that the acidified material was successfully prepared.

[0049] 3. Effects of acidifying materials and ripening agents on the quality of compost products

[0050] Cow dung and sawdust were mixed evenly at a carbon-nitrogen ratio of 25:1 and added to an aerobic composting device. The acidified material prepared under the optimal acidification conditions was added to the aerobic composting device and mixed evenly to obtain a compost material with a water content of 60%. The effect of acidified materials on composting was studied. Furthermore, while adding acidified materials, composting agents (bacterial agents, enzyme preparations, biochar) were also added, wherein the bacterial agents accounted for 0.5% of the total mass of the composting materials, the enzyme preparations accounted for 0.5% of the total mass of the composting materials, and the biochar accounted for 3% of the total mass of the composting materials. The effect of the combination of acidified materials and composting agents on composting was studied. The control group was set up without adding acidified materials and only adding composting agents. The experimental settings are shown in Table 2 below:

[0051] Table 2 Experimental design

[0052]

[0053] See also Figure 4The results of the effects of different additives on composting temperature showed that compared with no acidifying material (N1), the addition of acidifying material (N2) made the composting material enter the high temperature period one day earlier, and the peak temperature of the compost increased by 1.2℃. Compared with the addition of only acidifying material (N2) or only adding composting promoter (N3), when acidifying material and composting promoter were added together (N4), the composting entered the high temperature period on the second day of composting, and the compost temperature reached 67.2℃, which was 5.5℃ and 4.8℃ higher than the temperatures of N2 and N3, respectively. During the composting process, the peak temperature of the N4 treatment was 72.9℃, which was 2.8~4.9℃ higher than the compost peaks of other treatments (N1~N3). This shows that the acidifying material and the composting promoter have a synergistic effect, jointly promoting the increase of compost temperature, thereby helping to accelerate the composting process.

[0054] Referring to Table 3, the results of the parameters of the compost product with different additives show that the pH value of the compost product is 8.13 without the addition of acidifying material (N1), and the pH value of the compost product is reduced to 8.03 and 7.90 after the addition of acidifying material (N2, N4). The results of the influence of different additives on the conductivity of the compost show that when the acidifying material is not added (N1), the conductivity of the compost product is 1.53mS / cm, and after the addition of acidifying material (N2), the conductivity of the compost product is reduced by 1.96%, and after the acidifying material and the decomposition agent are added together (N4), the conductivity of the compost product is reduced by 9.80%. The salt content can be reflected by measuring the conductivity. The above results show that the salt content of the compost product obtained by the method of the present invention is significantly reduced, which is conducive to reducing or avoiding the risk of salt damage caused by the application of organic fertilizers. After the composting is completed, the available nutrients of the compost product are tested. Compared with N1, after adding acidified materials (N2), the contents of alkaline hydrolyzed nitrogen, available phosphorus, and available potassium in the compost product were increased by 12.69%, 0.3%, and 6.18%, respectively. After adding acidified materials and decomposition promoters together (N4), the alkaline hydrolyzed nitrogen content was 9.92% to 26.01% higher than that of other treatments (N1 to N3), the available phosphorus content was 1.56% to 2.96% higher than that of other treatments (N1 to N3), and the available potassium content was 3.01% to 5.67% higher than that of other treatments (N1 to N3). This shows that the acidified materials and decomposition promoters have a synergistic effect, which promotes nutrient conversion and increases the available nutrient content of the compost material.

[0055] Table 3 Parameters of compost products treated with different methods

[0056]

[0057] See also Figure 5The results of the effects of different additives on nitrogen loss (A) and carbon loss (B) of compost showed that without adding acidifying materials (N1), the carbon and nitrogen losses of the compost were 36.62% and 36.22%. After adding acidifying materials (N2), the carbon and nitrogen losses of the compost dropped to 24.80% and 19.89%. This shows that the addition of acidifying materials promoted the material transformation of the compost and reduced the carbon and nitrogen losses. When acidifying materials and composting agents were added together (N4), the carbon and nitrogen losses of the compost were the lowest, at 19.62% and 16.18%, respectively.

[0058] The maturity of compost can be determined based on its phytotoxicity. Mature compost products are not phytotoxic. The seed germination index comprehensively reflects the phytotoxicity of compost products and is a sensitive and most commonly used compost maturity evaluation indicator. According to the national standard NY / T 525-2021 "Organic Fertilizer", the technical indicator of organic fertilizer maturity is a seed germination index ≥ 70%. See Figure 6 The results of the effects of different additives on the seed germination index of compost showed that when the compost fermented to the maturity stage, all the treatment materials had reached the maturity standard, and the seed germination index of each treatment was 81.32% to 86.32%. After adding acidified materials (N2 and N4), the maturity time was 9 days and 7 days respectively, which was shortened by 1 to 3 days compared with the group without acidified materials (N1), indicating that acidified materials can accelerate the maturity of compost. Among them, compared with only adding acidified materials (N2) or only adding maturity promoters (N3), after adding acidified materials and maturity promoters together (N4), the seed germination index of the compost product was the highest, reaching 86.32%, and it reached maturity on the 7th day. The reason is that the acidified materials and the maturity promoters play a synergistic role, which accelerates the maturity process of the materials.

[0059] The present invention also provides a composting and fermentation device for organic waste, see Figure 7-Figure 8 The composting fermentation device for organic waste comprises an acidification device 10, an aerobic composting device 20, and a control system. The acidification device 10 is arranged above the aerobic composting device 20. The acidification device 10 is a closed conical bucket structure. The top of the acidification device 10 is provided with a first feeding port 11, a second feeding port 12, and an automatic exhaust valve 13. The first feeding port 11 is used to add organic waste into the acidification device 10, and the second feeding port 12 is used to add water or nutrient liquid into the acidification device 10 to adjust the water content or carbon-nitrogen ratio of the material. Since organic waste will produce H during the acidification and hydrolysis process, 2 , CO 2The gas such as argon and so on increases the internal pressure of the device, so an automatic exhaust valve 13 is installed to keep the anaerobic conditions inside the device and the device pressure within a safe range; the bottom of the acidification device 10 is provided with an acidification material discharge port 14, and the acidification material discharge port 14 is connected to the aerobic composting device 20. An automatic discharge device 15 is provided at the acidification material discharge port 14. The automatic discharge device 15 controls the opening of the acidification material discharge port 14 according to the gravity of the acidification material to send the acidification material in the acidification device 10 into the aerobic composting device 20; the aerobic composting device 20 includes a fermentation cylinder 21, a gear turntable 22, a drive motor 24, and a support base 23. The fermentation cylinder 21 The fermentation cylinder 21 is horizontally arranged on a support base 23, and is a hollow structure. One end of the fermentation cylinder 21 is provided with an acidified material feed port 211, a detection port 213, and an organic waste feed and inflation port 212 for organic waste and gas to enter. The organic waste feed and inflation port 212 is connected to an external inflation device. The acidified material feed port 211 of the fermentation cylinder 21 is connected to the acidified material discharge port 14 of the acidification device 10. The other end of the fermentation cylinder 21 is provided with a dehumidification port 214, a compost product discharge port 215, and a leachate discharge port 216. The dehumidification port 214 is provided with an exhaust valve. The gear turntable 22 is fixed around the fermentation cylinder 2 1, the driving end of the driving motor 24 is meshed with the gear turntable 22 to drive the fermentation cylinder 21 to rotate, turn the compost material in the fermentation cylinder 21, keep the pile in an aerobic state, promote the uniform degradation of organic matter, and then ensure the uniform mixing and maturity of the materials, so that all the materials stay in the high temperature area inside the compost for a certain period of time to meet the needs of sterilization and harmlessness of the materials; the acidification device 10 and the fermentation cylinder 21 are also respectively provided with heaters. Since the acidification time and compost maturity time have a certain correlation with the material composition and the ambient temperature, the smaller the molecular weight of the organic matter in the raw material, the easier it is to be degraded by microorganisms. The ambient temperature is 30℃~60℃ ℃, the acidification rate is the fastest. If no heating is performed, the acidification time is 6 to 9 days, and the composting time is 12 to 20 days. By arranging heaters in the acidification device 10 and the fermentation cylinder 21 to heat the materials, the acidification time is shortened to 4 to 6 days, and the composting time is shortened to 7 to 10 days, thereby improving the composting efficiency; the control system is electrically connected to the heater of the acidification device 10, the drive motor 24, the inflation device, the exhaust valve, and the heater of the fermentation cylinder 21, respectively, so as to control the temperature of the material in the acidification device 10, the discharge of the acidified material, the rotation speed of the fermentation cylinder 21, the inflation, the exhaust, and the temperature of the material in the fermentation cylinder 21, thereby realizing automatic adjustment of the environment in the fermentation cylinder 21.

[0060] Specifically, the automatic discharging device 15 includes a baffle plate 151 and a discharging end pressure sensor 152. The baffle plate 151 is rotatably connected to the acidified material discharge port 14. The discharging end pressure sensor 152 is installed on one side of the baffle plate 151. The discharging end pressure sensor 152 is connected to the control system. The weight of the acidified material in the acidifying device 10 is detected by the discharging end pressure sensor 152, and the detection signal is transmitted to the control system. The control system controls the opening or closing of the baffle plate 151 according to the signal transmitted by the discharging end pressure sensor 152.

[0061] Furthermore, temperature and humidity sensors 217 are provided at both ends of the fermentation cylinder 21. The control system is electrically connected to the temperature and humidity sensors 217 and receives signals transmitted by the temperature and humidity sensors 217 to control the heater to adjust the initial temperature of the compost material.

[0062] Furthermore, a dust and ammonia removal filter 2141 is provided at the dehumidification outlet 214. Since the compost material is animal and plant waste, it contains a certain amount of water. During the fermentation process, the water will evaporate continuously due to the rise in temperature, and some organic matter will decompose and mature, thereby reducing the volume of the fermented material. During the process, ammonia smell, hydrogen sulfide smell, etc. will be generated, which will have different degrees of toxic effects on human respiratory, digestive, cardiovascular, endocrine and nervous systems. Therefore, a dust and ammonia removal filter 2141 is provided at the dehumidification outlet 214 to deal with the odor.

[0063] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A composting and fermentation method for organic waste, characterized in that: The following steps are involved: (1) Biological acidification: The organic waste is crushed and added to an acidification device for biological hydrolysis and acidification. The carbon-nitrogen ratio of the organic waste is 29-32:1, the water content is 90%-94%, the acidification temperature is 15°C-35°C, and the acidification time is 4-9 days. The acidification device is kept in a closed state during operation. After the acidification is completed, a solid-liquid mixed acidified material is obtained, and the pH value of the acidified material is 5.0-5.5; (2) Aerobic composting fermentation: the acidified material obtained in step (1) and the organic waste used to prepare the acidified material are mixed and added into an aerobic composting device as compost material for aerobic composting fermentation. The carbon-nitrogen ratio of the compost material is 25-30:1, the water content is 60%-70%, the initial temperature is 30° C.-55° C., the composting time is 7-20 days, and the compost product is obtained after the fermentation is completed.

2. The composting and fermentation method of organic waste according to claim 1, characterized in that: In step (1), the carbon-nitrogen ratio of the organic waste is 31:1, the water content is 92%, the acidification temperature is 35°C, and the acidification time is 4 days; in step (2), the carbon-nitrogen ratio of the compost material is 25:1, the water content is 60%, the initial temperature is 35°C, and the composting time is 7 days.

3. The composting and fermentation method of organic waste according to claim 1, characterized in that: In step (2), during aerobic composting fermentation, a decomposition promoting agent is added to the aerobic composting device, wherein the decomposition promoting agent is a mixture of bacterial agent, enzyme preparation and biochar.

4. The composting and fermentation method of organic waste according to claim 3, characterized in that: The bacterial agent accounts for 0.5%~1.0% of the total mass of the compost material, the enzyme preparation accounts for 0.5%~1.0% of the total mass of the compost material, and the biochar accounts for 1%~3% of the total mass of the compost material.

5. An organic waste composting fermentation device suitable for the organic waste composting fermentation method according to any one of claims 1 to 4, characterized in that: The composting and fermentation device for organic waste comprises an acidification device, an aerobic composting device, and a control system. The acidification device is arranged above the aerobic composting device. The acidification device is a closed conical bucket structure. The top of the acidification device is provided with a first feeding port, a second feeding port, and an automatic exhaust valve. The first feeding port is used to add organic waste into the acidification device. The second feeding port is used to add water or nutrient liquid into the acidification device to adjust the water content or carbon-nitrogen ratio of the organic waste. The bottom of the acidification device is provided with an acidification material discharge port, which is connected to the aerobic composting device. An automatic discharging device is arranged at the discharging port of the acidified material, and the automatic discharging device controls the opening of the discharging port of the acidified material according to the gravity of the acidified material, so as to send the acidified material in the acidifying device into the aerobic composting device; the aerobic composting device comprises a storage barrel, a gear turntable, a driving motor, and a supporting base, the storage barrel is horizontally arranged on the supporting base, the storage barrel is a hollow structure, one end of the storage barrel is provided with an acidified material feed port, a detection port, and an organic waste feed port for organic waste and gas to enter, the organic waste feed and inflation port are connected to an external inflation device, and the acidified material feed port of the fermentation barrel is connected to the acidifying material feed port of the fermentation barrel. The storage barrel is connected to the acidification material discharge port of the acidification device, and the other end of the storage barrel is provided with a dehumidification port, a compost product discharge port, and a leachate discharge port. The dehumidification port is provided with an exhaust valve. The gear turntable is fixed around the outer wall of the storage barrel, and the driving end of the drive motor is meshed and connected with the gear turntable to drive the storage barrel to rotate and turn the compost material in the storage barrel to keep the pile in an aerobic state to promote the uniform degradation of organic matter. Heaters are also provided in the acidification device and the fermentation barrel respectively, and the control system is respectively connected to the heater, drive motor, inflation device, exhaust valve, and exhaust valve of the acidification device. The heater of the fermentation cylinder is electrically connected to control the temperature of the material in the acidification device, the discharge of the acidified material, the rotation speed of the fermentation cylinder, the inflation, the exhaust, and the temperature of the material in the fermentation cylinder; the automatic discharge device includes a baffle plate and a discharge end pressure sensor, the baffle plate is rotatably connected to the acidified material discharge port, the discharge end pressure sensor is installed on one side of the baffle plate, the discharge end pressure sensor is connected to the control system, the weight of the acidified material in the acidification device is detected by the discharge end pressure sensor, and the detection signal is transmitted to the control system, and the control system controls the opening or closing of the baffle plate according to the signal transmitted by the discharge end pressure sensor.

6. The composting and fermentation device for organic waste according to claim 5, characterized in that: Temperature and humidity sensors are also provided at both ends of the fermentation cylinder. The control system is electrically connected to the temperature and humidity sensors and receives signals transmitted by the temperature and humidity sensors to control the heater to adjust the initial temperature of the compost material.

7. The composting fermentation device for organic waste according to claim 5, characterized in that: A dust and ammonia removal filter is arranged at the moisture exhaust port.

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