Method for producing compost from plant residues and food residues, and compost produced by that method

Abstract

To produce compost from raw materials including vegetable residues and food residues.SOLUTION: The present disclosure relates to a novel method that the inventors have discovered and completed for efficiently and stably producing compost useful for plant growth from plant residues and food residues. By implementing the method of the present disclosure, it becomes possible to produce compost that is unlikely to cause reduction injury from raw materials including plant residues (e.g., vegetable residues) and food residues (e.g., discarded prepared foods and residues of bread and desserts).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing compost from feedstocks including plant and food residues, and the compost produced thereby. [Background technology]

[0002] Vegetable waste generated on farms and in homes, as well as food waste from food service factories, are serious problems. Composting is one method of treating these wastes, but these wastes have a high water content and a lower nitrogen content than livestock manure, which is commonly used as a composting material, making stable composting difficult. Summary of the Invention [Means for solving the problem]

[0003] The present inventors have discovered a novel method for efficiently and stably producing compost useful for plant growth from plant and food residues.

[0004] Thus, the present disclosure provides: (Item 1) A method for producing compost from raw materials including plant residues and food residues, comprising: 1) crushing and then dehydrating said plant residue; 2) mixing the dehydrated plant residue, the food residue, and secondary materials to obtain an initial raw material; 3) transferring the initial raw material to a primary fermentation zone, aerating the initial raw material 24 hours a day for about one week to about six weeks, and performing primary fermentation at an average temperature of the initial raw material of about 60°C to about 70°C to obtain a primary fermentation product; 4) transferring the primary fermentation product to a secondary fermentation zone and carrying out secondary fermentation at about 45°C to about 60°C for about 1 week to about 8 weeks to obtain a secondary fermentation product; 5) transferring the secondary fermentation product to a tertiary fermentation zone and carrying out tertiary fermentation at about 45°C to about 55°C for about 4 weeks to about 12 weeks to obtain a tertiary fermentation product; 6) Composting the tertiary fermentation product wherein the dehydrated vegetable residues and the dehydrated food residues comprise at least about 80% by weight of the raw material. Manufacturing method. (Item 2) The method for producing a fermented product according to any one of the preceding items, wherein in the secondary fermentation step 4), the primary fermentation product is aerated by stirring at a frequency of twice a day to once a day. (Item 3) The method for producing the fermented product according to any one of the preceding items, wherein in the tertiary fermentation step (5), the secondary fermentation product is aerated by turning it over at a frequency of twice a week to once a week. (Item 4) The method for producing a fermentation process according to any one of the preceding items, wherein the aeration in the primary fermentation is performed through an aeration tube. (Item 5) The method according to any of the preceding items, wherein the compost has a C / N ratio of less than 17. (Item 6) Item 10. The method of any preceding item, wherein the C / N ratio of the initial feedstock is at least 45. (Item 7) The production method according to any one of the preceding items, further comprising, prior to the primary fermentation step of 3), a step of pre-fermenting the initial raw material by forced aeration for about 1 day to about 2 weeks to raise the temperature of the initial raw material to about 50°C to about 70°C. (Item 8) The production method according to any one of the preceding items, wherein the water content of the initial raw materials is about 40 to about 80% (w / w). (Item 9) The manufacturing method according to any of the preceding items, wherein step 6) is a step of subjecting the tertiary fermentation product to quaternary fermentation at about 45°C or higher for about 1 week to about 12 weeks to obtain a quaternary fermentation product, and composting the quaternary fermentation product. (Item 10) The method for producing the fermented product according to any one of the preceding items, wherein aeration is not performed in the quaternary fermentation of the above item 6). (Item 11) The manufacturing method according to any one of the preceding items, wherein the secondary materials include rice husks and return compost. (Item 12) The manufacturing method according to any one of the preceding items, wherein the auxiliary materials further include waste mushroom beds. (Item 13) The method according to any one of the preceding items, wherein the return compost contains the tertiary fermentation product. (Item 14) Item 10. The method of claim 1, wherein the weight of the dehydrated plant residue and food residue accounts for about 90% of the weight of the raw material. (Item 15) The method according to any one of the preceding items, wherein the compost has a base exchange capacity (CEC) of at least 5. (Item 16) The method for producing a compost according to any one of the preceding items, wherein the weight of ammonia nitrogen is at least about 25% and the weight of nitrate nitrogen is at least about 25% of the total weight of ammonia nitrogen and nitrate nitrogen in the compost. (Item 17) Compost obtained by the method described in any of the preceding items.

[0005] It is contemplated that the present disclosure may provide one or more of the above-described features in combinations other than those explicitly stated. Still further embodiments and advantages of the present disclosure will be recognized by those skilled in the art upon reading and understanding the following detailed description, if necessary. [Effects of the Invention]

[0006] The present disclosure makes it possible to efficiently and stably produce compost useful for plant cultivation from raw materials including vegetable and food waste. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 shows a flow diagram of the compost production method of the present disclosure. [Figure 2] FIG. 2 shows the analysis results of the compost obtained by carrying out primary fermentation to quaternary fermentation. DETAILED DESCRIPTION OF THE INVENTION

[0008] (Definition, etc.) For convenience, certain terms used in this disclosure are collected here. Unless otherwise defined, all technical and scientific terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Unless the context clearly dictates otherwise, the singular form "a" , "an" and "the" include plural references.

[0009] The numerical ranges and parameters set forth in this disclosure are approximations. As used herein, the term "about" generally means 10% of a given value or range.

[0010] As used herein, "fermentation" refers to a phenomenon in which organic substances such as easily decomposable organic substances are decomposed by aerobic microorganisms into carbon dioxide and water.

[0011] As used herein, the term "plant residue" refers to residue that is 80% or more plant-derived. In a preferred embodiment, this may include, for example, vegetable residue, soybean residue, coffee grounds, tea leaves, etc.

[0012] As used herein, "food residue" refers to residue produced during the processing of human food.

[0013] As used herein, "secondary materials" refers to materials that are mixed into the composting feedstock to regulate the moisture content and ensure breathability of the feedstock.

[0014] As used herein, "return compost" refers to compost that has been reduced in moisture content. Return compost is generally used as bedding or secondary material and contains many microorganisms that contribute to fermentation.

[0015] As used herein, "waste mushroom bed" refers to residues generated during mushroom cultivation production, typically including sawdust and mycelium.

[0016] As used in this specification, "turning" refers to the transfer of raw materials that have already begun fermentation during the fermentation process, and by turning over the raw materials, the raw materials located at the surface of the pile are moved to the center of the pile, and at the same time, air is introduced into the raw materials, thereby recreating a fluffy and soft pile state with many voids, which activates decomposition and allows fermentation to occur uniformly.

[0017] As used herein, "cation exchange capacity (CEC)" is an index that indicates the ability to adsorb and retain bases (cations). The higher the value, the greater the ability to adsorb and retain Ca, a fertilizer component. 2+ , Mg 2+ , K. + , NH4 + It is evaluated as having a high ability to adsorb and retain cations such as ammonium nitrate and ammonium nitrate. It is also called the cation exchange capacity. The higher the CEC, the greater the compost's ability to retain fertilizer components.

[0018] As used in this specification, "C / N ratio" refers to the mass ratio of total carbon to total nitrogen (TC / TN) contained in raw materials or compost; the lower the C / N ratio, the higher the nitrogen content relative to the carbon content, and the higher the C / N ratio, the lower the nitrogen content relative to the carbon content.

[0019] As used herein, "ammonia nitrogen" refers to a nitrogen component that is an ammonium salt. Ammonia nitrogen is oxidized by nitrifying bacteria to nitrite nitrogen, and is further oxidized to nitrate nitrogen.

[0020] As used herein, "nitrate nitrogen" refers to nitrogen that exists in the form of nitrogen oxide, such as nitrate ions, among nitrogen components.

[0021] As used in this specification, "electrical conductivity" is a physical quantity that indicates the ease of electrical conduction in a substance, and is an indicator of the amount of water-soluble ions such as potassium and sodium in compost, and therefore the salt concentration.

[0022] (Compost manufacturing method) In one aspect, the present disclosure provides a method for producing compost from a feedstock comprising plant residues and food residues, the method comprising: 1) crushing and then dehydrating the plant residue; 2) mixing the dehydrated vegetable residue, food residue and secondary materials to obtain the initial raw material; 3) transferring the initial raw material to a primary fermentation zone, aerating the initial raw material for at least 20 hours over a period of about 1 week to about 6 weeks, and carrying out primary fermentation at an average temperature of the initial raw material of about 60°C to about 70°C to obtain a primary fermentation product; 4) transferring the primary fermentation product to a secondary fermentation zone and carrying out secondary fermentation at about 45°C to about 60°C for about 1 week to about 8 weeks to obtain a secondary fermentation product; 5) transferring the secondary fermentation product to a tertiary fermentation zone and carrying out tertiary fermentation at about 45°C to about 55°C for about 4 weeks to about 12 weeks to obtain a tertiary fermentation product; 6) The process of composting the tertiary fermentation product wherein the dehydrated vegetable and food residues comprise at least about 80% by weight of the raw material.

[0023] (Preparation of raw materials) In a preferred embodiment, the vegetable residues may include vegetable scraps, agricultural plant waste, raw material waste from preparing prepared foods, discarded prepared foods, and residues from bread and desserts (cakes, castella cakes, Japanese sweets, etc.).

[0024] In the present invention, the weight of the dehydrated plant and food residues may account for about 80% or more of the weight of the raw material. In a preferred embodiment, the weight of the dehydrated plant and food residues may account for about 90% or more of the weight of the raw material. In a typical embodiment of the present invention, the raw material for composting does not include bird or mammal manure. By not including manure, the raw material can be composted without generating a foul odor. In a most preferred embodiment, the weight of the dehydrated plant and food residues may be 100%.

[0025] In one embodiment, the water content of plant residue can be reduced by 1) crushing the plant residue and then dehydrating it. Because plant residues contain a large amount of water, composting has been difficult. However, the inventors have discovered that successful composting is possible by controlling the temperature range and duration during the fermentation stage. If the plant residue is not crushed, the cells in the plant residue break down after about a week, causing moisture from the plant residue to seep into the raw material, making it difficult to maintain a high temperature during the fermentation of the raw material and to quickly raise the temperature in the early stages of fermentation. Crushing the plant residue before fermenting the raw material and then dehydrating it makes it possible to maintain a high temperature during the fermentation of the raw material. Plant residue dehydration can be performed by various methods known in the art, such as belt press dehydration, centrifugal dehydration, and rotary pressure dehydration, but is preferably performed by compression dehydration. Compression dehydration is preferred because it allows for the dehydration of large amounts of crushed plant residue to be composted using simple equipment, reduced labor, and low energy. The dehydration of the plant residue can be carried out until the moisture content is appropriate for achieving the appropriate moisture content of the initial raw material, as described below. In one embodiment, the dehydration process can remove approximately 30 to approximately 70% of the moisture in the plant residue. In a preferred embodiment, the dehydration process can remove approximately 30 to approximately 50% of the moisture in the plant residue. In a most preferred embodiment, the dehydration process can remove approximately 40% of the moisture in the plant residue. The dehydration time can be appropriately determined by those skilled in the art depending on the target moisture content and dehydration method. In one embodiment, dehydration can be carried out for approximately 4 to 24 hours. In a preferred embodiment, dehydration can be carried out for approximately 12 to approximately 24 hours. In a most preferred embodiment, dehydration can be carried out for approximately 24 hours.

[0026] In one embodiment, an initial raw material with an adjusted moisture content can be obtained by carrying out step 2) of mixing dehydrated plant residues, food residues, and secondary materials to obtain an initial raw material. In a preferred embodiment, the secondary materials include rice husks, straw, sawdust, wood chips, waste mushroom beds, return compost, coffee grounds, tea leaves, fruit juice residue, and beer dregs.

[0027] In one embodiment, the moisture content of the initial raw materials may be about 40 to about 80% (w / w). In a preferred embodiment, the moisture content of the initial raw materials may be about 50 to about 80% (w / w). In a most preferred embodiment, the moisture content of the initial raw materials may be about 65 to about 75% (w / w). In one embodiment, the plant residue contained in the initial raw materials may include vegetable residue. In one embodiment, the food residue contained in the initial raw materials may include residues discharged from food factories (for example, residues from prepared food factories (raw material waste from preparing prepared foods, discarded prepared food waste) and bread and desserts (residues of cakes, castella, Japanese sweets, etc.). Vegetable residues and residues discharged from food factories are raw materials suitable for human consumption when fresh, so safe initial raw materials can be obtained by using vegetable residues as the plant residue and residues discharged from food factories as the food residue. In one embodiment, In some embodiments, the vegetable residue may be about 20% to about 60% (e.g., about 20%, about 30%, about 40%, about 50%, about 60%) of the total initial ingredients. In a preferred embodiment, the vegetable residue may be about 30% to about 50% of the total initial ingredients. In a most preferred embodiment, the vegetable residue may be about 30% to about 40% of the total initial ingredients. In one embodiment, the food residue may include eggshells, which may result in a higher calcium concentration in the final product than usual.

[0028] In one embodiment, secondary materials may include rice husks and / or backcompost.

[0029] In one embodiment, the volume ratio of the raw materials to the secondary materials may be raw materials:secondary materials = 1:1 to 4. In a preferred embodiment, the volume ratio of the raw materials to the secondary materials may be raw materials:secondary materials = 1:1 to 2. In one embodiment, coffee grounds may be used as the secondary material. In one embodiment, the return compost may contain tertiary fermentation products, which will be described later. Adding return compost to the raw materials as a secondary material makes it possible to efficiently transfer microorganisms involved in composting to the raw materials, thereby shortening the composting period and the time required to raise the temperature of the raw materials.

[0030] In one embodiment, the secondary material may include waste mushroom beds. Because waste mushroom beds contain sawdust and mushroom mycelium, adding waste mushroom beds to the raw materials results in sawdust fibers and some mushroom components remaining in the final product. This has a positive effect when the final product is used to grow plants. This is because one of the roles of compost in plant cultivation is soil improvement, and adding waste mushroom beds improves the physical properties of the soil by incorporating cellulose, lignin, and hemicellulose into the final product, resulting in a fluffy, soft soil. Furthermore, although the sawdust contained in waste mushroom beds contains phenolic substances, these are decomposed during composting. Compost made from waste mushroom beds contains high concentrations of antagonistic bacteria such as Streptomyces and Bacillus.

[0031] (Pre-fermentation) In one embodiment, the production method of the present invention may include a pre-fermentation step before the primary fermentation. The pre-fermentation step may be provided to reduce the moisture content in the raw material and improve the rise of fermentation in the primary fermentation (to increase the initial rate of fermentation).

[0032] In the pre-fermentation step, rice husks may be spread on the floor and walls of the area where pre-fermentation is carried out. Rice husks create voids, which can contribute to moisture drainage and efficient ventilation. Furthermore, spreading rice husks can prevent clogging of the ventilation nozzles. In one embodiment, rice husks are mixed into the pre-fermentation product after the pre-fermentation treatment. In one embodiment, fibrous plant waste (e.g., rice straw) can be used instead of rice husks. In one embodiment, rice husks may be spread to a height of about 5 to about 70 cm, preferably about 5 to 60 cm, and most preferably about 5 cm, on the area where pre-fermentation is carried out. This allows moisture to escape while providing efficient ventilation.

[0033] The pre-fermentation step is carried out before the primary fermentation step (3), in which the initial raw material is pre-fermented by forced aeration for about one day to about two weeks, raising the temperature of the initial raw material to about 50°C to about 70°C. In a preferred embodiment, the initial raw material can be pre-fermented by forced aeration for about three to about ten days before the primary fermentation step (3). In a most preferred embodiment, the initial raw material can be pre-fermented by forced aeration for about one week before the primary fermentation step (3). In one embodiment, the pretreatment step can be carried out in a location separate from the primary fermentation zone. In another embodiment, the pretreatment step can be carried out in the same location as the primary fermentation zone, in a state where the raw material being pre-treated is not mixed with the raw material being treated after primary fermentation. By carrying out the pretreatment step in a location separate from the primary fermentation zone, or in a state where it is not mixed with the raw material being treated after primary fermentation, it is possible to prevent harmful microorganisms contained in the raw material being pre-treated from being transferred to the raw material being treated after primary fermentation. The temperature of the raw material during pretreatment can reach the 40°C range one to two days after the start of pretreatment, and the 50°C range three to four days after the start of pretreatment. In a preferred embodiment, a mechanism is provided to drain water leaking from the raw material during pretreatment and primary fermentation so that it does not accumulate in the pretreatment area or primary fermentation area, thereby reducing the risk of harmful microorganisms contained in the initial raw material being mixed into the primary fermentation and preventing the generation of unpleasant odors during fermentation.

[0034] (Primary fermentation process) In the production method of the present invention, primary fermentation is carried out by maintaining a temperature of 50°C or higher to reduce harmful microorganisms to a substantially harmless level. In one embodiment, primary fermentation can be carried out at an average temperature of the initial raw material of about 50°C to about 70°C. By maintaining an appropriate temperature for about 2 to 3 months between primary fermentation and tertiary fermentation, harmful microorganisms contained in the raw material (e.g., Salmonella, Escherichia coli, Campylobacter, etc.) can be killed and substances harmful to crop growth (e.g., phenolic compounds, lower fatty acids, etc.) can be decomposed (maintaining the temperature for about 2 to 3 months reduces the number of harmful microorganisms contained in the initial raw material by 10 orders of magnitude from the initial bacterial count, and they can be killed to a virtually harmless level). In one embodiment, primary fermentation can be carried out at an average temperature of the initial raw material of about 70°C or lower. By maintaining the temperature at about 70°C or lower, the risk of death of microorganisms useful for composting (e.g., Bacillus bacteria, actinomycetes, nitrifying bacteria (ammonia-oxidizing bacteria, nitritizing bacteria)) can be reduced. Water may be added to the initial ingredients to keep the average temperature of the initial ingredients below about 70°C during primary fermentation.

[0035] In one embodiment, continuous or intermittent aeration can be performed in 3) the step of obtaining a primary fermentation product. In one embodiment, aeration can be performed for about 1 to 6 weeks, for example, about 1 to 4 weeks, about 2 to 6 weeks, or about 3 to 6 weeks, at a time and aeration rate that can prevent the fermentation target from becoming anaerobic. In a preferred embodiment, aeration can be performed daily for about 2 to 5 weeks in the step of obtaining a primary fermentation product. In a most preferred embodiment, aeration can be performed daily for about 3 to 5 weeks, for example, about 4 weeks in the step of obtaining a primary fermentation product. By aerating the fermentation target daily, the oxygen demand of the aerobic microorganisms that decompose the fermentation target can be met. Daily aeration in primary fermentation can be constant aeration for 24 hours. If the aforementioned oxygen demand can be met, the aeration time can be shortened. Furthermore, aeration of the fermentation target for a long period of time every day, for example, 24 hours, can prevent the fermentation target from becoming anaerobic, and aerobic fermentation can be promoted. This makes the fermentation target aerobic, preventing the denitrification reaction of denitrifying bacteria, which are more active under anaerobic conditions, and also prevents the denitrification of nitrate nitrogen in the fermentation target, leading to an increase in the amount of nitrogen in the produced compost. Furthermore, aeration for a long period of time, for example 24 hours, can prevent the nozzles of the aeration equipment from clogging.

[0036] In one embodiment, the primary fermentation treatment can be carried out in separate locations for each fermentation stage. In a preferred embodiment, the primary fermentation treatment can be carried out in separate weeks after the start of fermentation (e.g., week 1, week 2, week 3, etc.). By carrying out the primary fermentation in separate locations for each fermentation stage, such as by moving the location for each fermentation stage, heat accumulation in the fermentation target can be prevented, and an increase in temperature above 70°C, which can result in the death of nitrifying bacteria, can also be prevented.

[0037] In one embodiment, aeration in primary fermentation can be through an aeration pipe. In one embodiment, the aeration pipe may be an aeration pipe laid on the floor of the primary fermentation area, or a rod-shaped aeration pipe that can be inserted into the raw material or fermentation product. 3 To advance 1% of the flow rate, approximately 3-7 L / m 3 / min is required, so if the raw material is piled up to 2m, the required air volume is 6 to 14L / m 2 Therefore, in one embodiment, the amount of air supplied from the air diffuser is about 3 to 32 L / m 2 / min or more. In a preferred embodiment, the flow rate is about 5-17 L / m 2 / min or more. In the most preferred embodiment, the air supply rate from the air diffuser is 6 to 14 L / m 2 / min or even more.

[0038] (Secondary fermentation treatment) In the present invention, the secondary fermentation step is aimed at reducing harmful microorganisms to a substantially harmless level by maintaining a fermentation temperature of about 45°C or higher while aerating at a lower frequency than in the primary fermentation step. In one embodiment, in the secondary fermentation step 4), aeration by stirring the primary fermentation product can be performed twice a day to once a day. In a preferred embodiment, aeration by stirring the primary fermentation product can be performed once a day to once a day. In a most preferred embodiment, aeration by stirring can be performed four times every two days. Stirring can homogenize the primary fermentation product and prevent it from becoming anaerobic. In one embodiment, stirring can be performed using a rotary stirrer. In one embodiment, the secondary fermentation is maintained at a temperature in the high 40s to low 50s (45°C to 54°C). Maintaining such a temperature activates aerobic fermentation microorganisms and also activates nitrifying bacteria. In one embodiment, the secondary fermentation can be carried out at a temperature not exceeding 70° C. to prevent the death of nitrifying bacteria.

[0039] In one embodiment, the secondary fermentation step 4) can be carried out for about 1 week to about 12 weeks. In a preferred embodiment, the secondary fermentation step 4) can be carried out for about 1 week to about 8 weeks, about 1 week to about 4 weeks, about 2 weeks to about 12 weeks, about 3 weeks to about 8 weeks, about 3 weeks to about 12 weeks, about 4 weeks to about 8 weeks, or about 4 weeks to about 12 weeks. In a most preferred embodiment, the secondary fermentation step 4) can be carried out for about 2 weeks to about 8 weeks, for example, about 6 weeks. By carrying out the secondary fermentation for the above period, it is possible to reduce the amount of easily decomposable organic matter.

[0040] In one embodiment, the secondary fermentation step 4) can be carried out at about 45°C to about 75°C. In a preferred embodiment, the secondary fermentation step 4) can be carried out at about 45°C to about 65°C. In a most preferred embodiment, the secondary fermentation step 4) can be carried out at about 45°C to about 60°C.

[0041] (Tertiary fermentation process) In the present invention, the tertiary fermentation step maintains the fermentation temperature at about 45°C or higher while aeration is performed at an even lower frequency than in the secondary fermentation step. In one embodiment, in the tertiary fermentation step 5), aeration by back-and-forth stirring of the secondary fermentation product can be performed twice a week to once a week. In a preferred embodiment, in the tertiary fermentation step 5), aeration by back-and-forth stirring of the secondary fermentation product can be performed once a week to once a week. In a most preferred embodiment, in the tertiary fermentation step 5), aeration by back-and-forth stirring of the secondary fermentation product can be performed once a week to once a week. The reason for reducing the aeration frequency in tertiary fermentation compared to secondary fermentation is that the amount of easily decomposable organic matter contained in the target of tertiary fermentation is less than the amount of easily decomposable organic matter contained in the target of secondary fermentation, making it difficult for the temperature of the target of tertiary fermentation to rise. Therefore, by reducing the aeration frequency, which involves heat release, the temperature of the target of tertiary fermentation can be maintained.

[0042] In one embodiment, the tertiary fermentation step (5) may be carried out for about 2 weeks to about 12 weeks. In a preferred embodiment, the tertiary fermentation step (5) may be carried out for about 4 weeks to about 10 weeks. In a most preferred embodiment, the tertiary fermentation step (5) may be carried out for about 8 weeks.

[0043] In one embodiment, the tertiary fermentation step 5) may be carried out at about 45°C to about 75°C. In a preferred embodiment, the tertiary fermentation step 5) may be carried out at about 45°C to about 65°C. In a most preferred embodiment, the tertiary fermentation step 5) may be carried out at about 45°C to about 55°C. The tertiary fermentation product may be returned to the compost as described above.

[0044] (Quaternary fermentation) In the present invention, a quaternary fermentation step may be provided. The quaternary fermentation step may be performed without aeration, by reducing easily decomposable organic matter, to prevent rapid proliferation of microorganisms in the soil when used as compost, thereby preventing reduction damage that would cause the soil to become anaerobic. In one embodiment, 6) the step of converting the tertiary fermentation product into compost may include a step of subjecting the tertiary fermentation product to quaternary fermentation at about 45°C to about 55°C for about 1 week to about 12 weeks to obtain a quaternary fermentation product, and converting the quaternary fermentation product into compost. In a preferred embodiment, 6) the step of converting the tertiary fermentation product into compost may include a step of subjecting the tertiary fermentation product to quaternary fermentation for about 3 weeks to about 8 weeks to obtain a quaternary fermentation product, and converting the quaternary fermentation product into compost. In a most preferred embodiment, 6) the step of converting the tertiary fermentation product into compost may include a step of subjecting the tertiary fermentation product to quaternary fermentation for about 4 weeks to obtain a quaternary fermentation product, and converting the quaternary fermentation product into compost. In one embodiment, aeration is not performed in the quaternary fermentation. In one embodiment, the quaternary fermentation process may be carried out for a predetermined period of time, or may be terminated without a set period of time, when the temperature drops below a certain level while monitoring the temperature, etc. In a preferred embodiment, the quaternary fermentation process is carried out without a set period of time, when the temperature drops below a certain level while monitoring the temperature, etc. In one embodiment, the quaternary fermentation is carried out in a container such as a flexible container, and is terminated when the temperature drops and the container is opened and turned over, resulting in no increase in temperature. By fermenting the compost until the temperature does not increase even when turned over, the amount of easily decomposable organic matter in the compost can be sufficiently reduced. This prevents reduction damage, which would occur if the compost were used as compost, as would result in rapid proliferation of microorganisms and the soil becoming anaerobic. In one embodiment, sieving may be carried out after completion of the process.

[0045] (Compost properties) In one embodiment, the compost may have a pH of about 7 and an electrical conductivity (EC) of 10 mS / cm or less. In a preferred embodiment, the compost may have an electrical conductivity (EC) of 8 mS / cm or less. In a most preferred embodiment, the compost may have an electrical conductivity (EC) of 6 mS / cm or less. If the electrical conductivity of the compost is within the above range, the salt concentration in the compost is not high, and therefore, when the compost is applied to soil, growth disorders (salt concentration disorders), such as the inability of crop roots to absorb water, are unlikely to occur.

[0046] In one embodiment, the compost of the present disclosure contains waste fungal beds as a raw material, and therefore may contain a large amount of Streptomyces and Bacillus, which have disease-suppressing effects.

[0047] In one embodiment, the C / N ratio of the initial feedstock may be at least 30. In a preferred embodiment, the C / N ratio of the initial feedstock may be at least 40. In a most preferred embodiment, the C / N ratio of the initial feedstock may be at least 45. In one embodiment, the C / N ratio of the compost produced by the method of the present disclosure may be less than 20 (e.g., less than 20, less than 19, less than 18, less than 17, or less than 16). In a preferred embodiment, the C / N ratio of the compost produced by the method of the present disclosure may be less than 19. In a most preferred embodiment, the C / N ratio of the compost produced by the method of the present disclosure may be less than 17. Compost with a low C / N ratio is compost that contains no readily decomposable organic matter and is less likely to cause reduction damage when used as compost, which would cause microorganisms to rapidly grow in soil and cause the soil to become anaerobic.

[0048] In one embodiment, the compost may contain more ammonia nitrogen than nitrate nitrogen. This is because ammonia nitrogen is a cation and therefore has the advantage of being easily adsorbed and retained in soil, making it more likely to be used as a fertilizer component when applied to fields. In another embodiment, the compost may contain more nitrate nitrogen than ammonia nitrogen. This is because nitrate nitrogen is less likely to produce a foul odor than ammonia nitrogen. In one embodiment, the ratio of nitrate nitrogen to ammonia nitrogen may be about 1:2 to about 2:1. This is because the inclusion of ammonia nitrogen has the advantage of being easily adsorbed and retained in soil, making it more likely to be used as a fertilizer component when applied to fields, and the presence of nitrate nitrogen makes it less likely to produce a foul odor compared to when ammonia nitrogen is present in large amounts. In one embodiment, the weight ratio of ammonia nitrogen to nitrate nitrogen is 2:1 to 1:3. In a preferred embodiment, the weight ratio of ammonia nitrogen to nitrate nitrogen is 1:1 to 1:3. In one embodiment, the weight of ammonia nitrogen and the weight of nitrate nitrogen in the compost of the present disclosure may be at least 25%, and the weight of nitrate nitrogen may be at least 25%. In a preferred embodiment, the weight of ammonia nitrogen and the weight of nitrate nitrogen in the compost of the present disclosure may be at least 30%, and the weight of nitrate nitrogen may be at least 30%. In a most preferred embodiment, the weight of ammonia nitrogen and the weight of nitrate nitrogen in the compost of the present disclosure may be at least 40%, and the weight of nitrate nitrogen may be at least 40%. Ammonia nitrogen volatilizes as ammonia in a neutral to weakly alkaline pH range of 7.6 to 8, which can cause a foul odor and lead to nitrogen loss. However, because it is a cation, it has the advantage of being easily adsorbed and retained in the soil, and is not wasted as a fertilizer component when applied to fields. Nitrate nitrogen is converted to NO3 - Therefore, it is difficult for it to be adsorbed by soil, and it is washed away by rain and other things, such as groundwater. Although this can lead to environmental pollution, it has the advantage of being less likely to cause odor problems. In one embodiment, the sum of ammonia nitrogen and nitrate nitrogen can be about 10 to about 20% of the total nitrogen amount, and organic nitrogen can be about 80 to about 90% of the total nitrogen amount. Organic nitrogen becomes ammonia nitrogen as organic matter containing microbial cells is decomposed, is discharged from the organic matter, and then becomes nitrate nitrogen, allowing for sustained nitrogen release.

[0049] In one embodiment, compost made from plant and food residues contains appropriate amounts of nitrogen, phosphorus, and potassium, and is also rich in fiber, making it ideal for soil improvement. Excessive amounts of phosphorus and potassium can increase soil salinity, leading to growth disorders (salt-induced damage) such as the inability of crop roots to absorb water. However, phosphorus promotes flowering and fruiting, while potassium promotes root development and increases resistance to temperature and pests. Therefore, even low levels of phosphorus and potassium can have a negative impact on plant growth. Furthermore, the high fiber content improves the soil's physical properties, resulting in soft soil.

[0050] In one embodiment, the base exchange capacity (CEC, units: meq / 100g or cmol(+) kg -1 ) can be at least 5 (e.g., 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40). In preferred embodiments, the base exchange capacity (CEC) of the compost can be at least 8. In most preferred embodiments, the base exchange capacity (CEC) of the compost can be at least 10. The higher the CEC, the greater the ability to adsorb and retain cations, and therefore the greater the amount of nutrients retained by the compost.

[0051] The present disclosure has been described above by showing preferred embodiments for ease of understanding. The present disclosure will be described below based on examples. However, the above description and the following examples are provided for illustrative purposes only and are not intended to limit the present disclosure. Therefore, the scope of the present disclosure is not limited to the embodiments or examples specifically described herein, but is limited only by the scope of the claims. [Example]

[0052] (Example 1-1: Preparation of raw materials) Vegetable scraps were used as plant residues, and food waste (e.g., cut vegetable scraps, prepared food scraps, noodle factory scraps, mentaiko factory scraps, bread factory scraps, and confectionery factory scraps) discharged from food factories and food processing factories were used as food residues. These were loaded separately onto trucks, covered with sheets, and transported to the factory where the fermentation took place. The transported vegetable scraps and food waste were unloaded in separate locations while still fresh. Waste mushroom beds had been laid in advance at the unloading area as moisture absorbent. The unloaded vegetable scraps (approximately 2 tonnes) were crushed in a biaxial crusher, and the crushed material was placed in a container and left for 24 hours until the moisture content reached approximately 60%.

[0053] The vegetable waste with reduced moisture content was mixed with food waste in a ratio of approximately 1:1 (4 t in total). Secondary materials, including rice husks, waste mushroom beds, and return compost, were then further mixed with the vegetable waste / food waste mixture in a ratio of approximately 2:1, yielding 7 t of raw material. The moisture content of the raw material was approximately 80%, and the C / N ratio was approximately 60.

[0054] (Example 1-2: Pre-fermentation) (Days 1-2) In the area where the aeration system (EasyJet by Miraie Co., Ltd.) was installed on the floor for the pre-fermentation, rice husks were laid about 5 cm thick, and the raw materials were piled on top of that to a height of about 2 m. The aeration rate of the aeration system on the first day was 2.44 L / m. 3 / min, and the aeration system on the second day was 2.44 L / m 3 The aeration rate was set at 1 / min for 24 hours. Each day for one week, the collected material was added.

[0055] (Day 3) Set the ventilation volume to 6.1 L / m 3 The aeration rate was changed to / min for 24 hours. The temperature of the raw material was in the 50°C range.

[0056] (Day 7) The raw materials were left in the pre-fermentation area for one week without stirring or turning over, and then mixed with rice husks laid on the floor. The temperature of the raw materials was in the 50°C range.

[0057] (Example 1-3: Primary fermentation) The pre-fermented raw material was placed in a primary fermentation area with walls lined with rice husks at a height of about 2 m. The aeration rate of the aeration system was 6.1 L / m. 3 The flow rate was set to / min. Every week, the raw material was moved to another location in the primary fermentation area, which was covered with about 5cm of rice husks. When moving, the rice husks that had been laid on the floor were mixed with the raw material. Primary fermentation was carried out for three weeks, with the fermentation location being moved every week. Water leaking from the raw material during pretreatment and primary fermentation was moved to tanks located below the pretreatment and primary fermentation areas, so that it did not accumulate in the pretreatment and primary fermentation areas. During primary fermentation, the temperature was maintained at around 60-70°C, except immediately after stirring.

[0058] (Example 1-4: Secondary fermentation) After primary fermentation, the raw material was transferred to the secondary fermentation area and placed at a height of approximately 1 m. In the secondary fermentation area, a rotary mixer (6 m wide x 1 m high x 80 m) was used to mix the material once every two days, with four mixes per mix. After mixing, the temperature of the raw material dropped to the 50°C range within half a day. Secondary fermentation was continued for approximately six weeks, maintaining a temperature of approximately 60-70°C except immediately after mixing.

[0059] (Example 1-5: Tertiary fermentation) After secondary fermentation, the raw material was transferred to the tertiary fermentation area and placed at a height of about 2m. In the tertiary fermentation area, the mixture was stirred by turning it over about once a week. Except for the time immediately after turning it over, the temperature was maintained at about 60-70°C, and tertiary fermentation was carried out for about 8 weeks.

[0060] (Example 1-6: Quaternary fermentation) The raw material that had undergone tertiary fermentation was transferred to a flexible container (quaternary fermentation area). Quaternary fermentation continued in the quaternary fermentation area for approximately one month without stirring, yielding compost. After one month, it was confirmed that the temperature had dropped below 10°C above ambient temperature, and that there was no temperature increase even after turning. After confirming that there was no temperature increase, the pH and electrical conductivity of the compost were measured, confirming that the pH was around 7 (pH 7.7) and the electrical conductivity was 8ms / cm or less (7.8). After confirmation, the compost was sieved using a rotary sieve with 4mm mesh and packed into 16L bags.

[0061] The compost was analyzed by the Toyo Environmental Analysis Center. The results are shown in Figure 2. The high base exchange capacity of 10.3 indicated that the compost had the capacity to retain a large amount of nutrients. Furthermore, the C / N ratio was sufficiently low at 15, indicating that the compost had undergone sufficient fermentation, contained no readily decomposable organic matter, and was resistant to reduction damage. Furthermore, the ammonia nitrogen concentration was 0.16%, the nitrate nitrogen concentration was 0.09%, and the total nitrogen content was 1.5%, indicating that the organic nitrogen was approximately 83% and capable of providing a sustainable supply of nitrogen. Furthermore, the electrical conductivity was 7.8 ms / cm, indicating that the salt concentration was not high and that the compost was resistant to crop growth damage. In addition, because waste mushroom beds are used as secondary materials, the compost contains cellulose, lignin, and hemicellulose, and contains high concentrations of antagonistic bacteria such as Streptomyces and Bacillus, so when used, the compost can improve the physical properties of the soil and make it possible to cultivate crops that are resistant to disease.In addition, because it is rich in silica, it is highly effective in preventing rice lodging.

[0062] (Example 2: Compost production without tertiary and quaternary fermentation) Compost was produced under the same conditions as in Example 1, except that tertiary and quaternary fermentation were not performed. As a result, compost was obtained, but the fermentation state of the compost was uneven compared to Example 1, and the C / N ratio was high. This is thought to be because there was a larger amount of easily decomposable organic matter remaining compared to the compost of Example 1. Without intending to be bound by theory, it is thought that the fermentation period of Example 1 was preferable.

[0063] (Example 3: Compost production without pre-fermentation treatment) Compost was produced under the same conditions as in Example 1, except that pre-fermentation was not performed in a separate location prior to primary fermentation. As a result, compared to Example 1, harmful microorganisms such as E. coli were sometimes detected in the compost. Although compost was successfully produced, not performing pre-fermentation in a separate location from primary fermentation could have resulted in harmful microorganisms in the raw materials being contaminated with the raw materials for primary fermentation. Therefore, it was found that it is better to perform pre-fermentation in separate locations from primary fermentation.

[0064] (Example 4: Compost production without transferring between fermentation stages in the primary fermentation treatment) Compost was produced under the same conditions as in Example 1, except that the fermentation location was not changed every week during the primary fermentation treatment stage. As a result, the compost had less nitrate nitrogen and more ammonia nitrogen than in Example 1. Although compost was successfully produced, not changing the location may have caused excessive heat accumulation in the fermentation target, which may have impaired the activity of nitrifying bacteria, which are sensitive to temperatures above 70°C. As in Example 1, it was found that it is better to periodically change the location during primary fermentation.

[0065] (Example 5: Compost production without rice husks in pre-fermentation treatment) Compost was produced under the same conditions as in Example 1, except that rice husks were not laid down in the pre-fermentation treatment stage. As a result, the moisture content of the fermentation target was higher and the C / N ratio was higher compared to Example 1. Although compost was successfully produced, not laying down rice husks may have lowered the oxygen concentration and prevented sufficient fermentation. It is preferable to perform the pre-fermentation treatment with rice husks laid down, as in Example 1.

[0066] (Example 6: Temperature during primary fermentation treatment) Compost was produced under the same conditions as in Example 1, except that the temperature of the primary fermentation treatment exceeded 70°C. As a result, the amount of nitrate nitrogen was reduced compared to the compost produced in Example 1. Although the compost was successfully produced, the fermentation temperature was too high, which may have impaired the activity of nitrifying bacteria, which are sensitive to temperatures above 70°C.

[0067] (Example 7: Temperature during secondary fermentation treatment) Compost was produced under the same conditions as in Example 1, except that the temperature of the secondary fermentation treatment exceeded 70°C. As a result, the amount of nitrate nitrogen was reduced compared to the compost produced in Example 1. Although the compost was successfully produced, the fermentation temperature was too high, which may have impaired the activity of nitrifying bacteria, which are sensitive to temperatures above 70°C.

[0068] (Example 8: Temperature during tertiary fermentation treatment) Compost was produced under the same conditions as in Example 1, except that the temperature in the tertiary fermentation treatment exceeded 70°C. As a result, the amount of nitrate nitrogen was reduced compared to the compost produced in Example 1. Although the compost was successfully produced, it is possible that the fermentation temperature was too high, which inhibited the activity of nitrifying bacteria, which are sensitive to temperatures above 70°C.

[0069] (Note) While the present disclosure has been illustrated using preferred embodiments thereof, it is understood that the scope of the present disclosure should be construed solely in terms of the claims that follow. It is understood that the patents, patent applications, and other documents cited herein are incorporated by reference into this specification in their entirety as if the contents themselves were specifically set forth herein. [Industrial Applicability]

[0070] Compost produced by the compost production method provided in the present disclosure is unlikely to cause reduction problems and is therefore believed to have great commercial value.

Claims

[Claim 1] The invention described in the specification.

Images