Livestock manure treatment method and soil improvement composition manufacturing method

Abstract

To provide a livestock excrement treatment method for efficiently and easily converting livestock excrement into processed organic material and a manufacturing method of a plant and soil modifying composition including the converted organic material as a major component.SOLUTION: A contact treatment device 35 included in a treatment facility 31 includes a contact treatment section 37 and a superheated steam supply section 38. Livestock excrement 11 is mixed with chaff and siliceous shale 19 into a granular admixture. The contact treatment device 35 performs contact treatment that brings the granular admixture as a treatment target into contact with the superheated steam. The treatment target may be the livestock excrement 11 solely or an admixture of the livestock excrement 11 and the chaff 15.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for treating livestock manure and a method for producing a soil improving composition. [Background technology]

[0002] It has long been recommended to lay organic materials (sawdust, rice husks, rice straw) on bedding in cowsheds as a measure against mastitis. However, organic bedding mixed with livestock manure often has high water retention and is difficult to decompose. As a result, it captures immature organic matter, including livestock manure, along with moisture, which becomes a source of odor during the fermentation period before it becomes compost, and because the bedding becomes immature organic matter during the normal fermentation period, it also causes the fermentation period to be longer.

[0003] In addition, while large-scale livestock farms separate feces and urine for processing, in livestock farms where the number of livestock is below the legal limit, the feces and urine are processed together, making moisture adjustment an essential part of the process, which is time-consuming.

[0004] To effectively utilize livestock manure, for example, Patent Document 1 discloses a carbonization device for carbonizing livestock manure, and Patent Document 2 discloses a method for semi-carbonizing biomass by blowing hot air under negative pressure onto livestock manure as biomass. Patent Document 3 also discloses a method for producing a silicic acid-containing powder in which rice husks or straw are placed in a treatment vessel, steam is injected into the vessel to increase the internal pressure and temperature, and the rice husks or straw are held under steam pressure to pulverize them without burning. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-159778 [Patent Document 2] Japanese Patent Application Publication No. 2019-045078 [Patent Document 3] Patent No. 3579417 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in carbonization and incineration, the carbon content decreases, which prevents the waste from functioning as compost and becoming inorganic mineral material. In other words, to prevent the loss of plant nutrients, lowering the treatment temperature lengthens the treatment time. Therefore, other methods for efficiently treating large amounts of livestock manure are desired. Furthermore, the method of Patent Document 3 requires precise setting of conditions because the internal pressure in the treatment vessel is increased and the rice husks or straw are pulverized without being burned.

[0007] Therefore, an object of the present invention is to provide a method for treating livestock manure that can efficiently and simply treat livestock manure, and a method for producing a soil improving composition. [Means for solving the problem]

[0008] The livestock manure treatment method of the present invention is characterized in that livestock manure alone is used as the treatment object, and superheated steam is brought into contact with the treatment object.

[0009] The object to be treated is preferably undried livestock manure, and the livestock manure preferably has a moisture content of at least 30%. The livestock manure treatment method preferably has a granulation step and a contact treatment step. The granulation step forms the livestock manure into granules. The contact treatment step brings the granulated livestock manure into contact with superheated steam.

[0010] The method for treating livestock manure of the present invention is characterized by contacting a mixture of livestock manure and a silicic acid-containing plant-derived organic material with superheated steam.

[0011] The siliceous plant-based organic material is preferably rice husk. Superheated steam is preferably brought into contact with livestock manure in which the siliceous plant-based organic material and granular siliceous shale have been mixed.

[0012] The livestock manure treatment method may include a siliceous shale mixing step, a hydration step, and a contact treatment step. The siliceous shale mixing step involves mixing a manure mixture of livestock manure and siliceous plant organic material with granular siliceous shale to form a siliceous shale mixture. The hydration step involves impregnating the siliceous shale mixture with liquid water. The contact treatment step involves contacting the siliceous shale mixture in a water-containing state with superheated steam.

[0013] The siliceous shale mixing step preferably involves mixing siliceous shale with an undried manure mixture. The livestock manure treatment method preferably further includes a granulation step of forming the siliceous shale mixture into granules. When the granulation step is included, the contact treatment step involves contacting the granulated, water-containing siliceous shale mixture with superheated steam. The granulation step may include the water-containing step.

[0014] In the above-mentioned livestock manure treatment method, the temperature of the treatment space in which the superheated steam comes into contact is preferably within the range of 160°C or higher and 400°C or lower.

[0015] The method for producing the soil modifying composition of the present invention involves contacting livestock manure having a moisture content of at least 30% with superheated steam to produce the soil modifying composition.

[0016] It is preferable to prepare a soil improving composition by contacting a mixture of livestock manure and silicic acid-containing plant-based organic material with superheated steam.

[0017] Superheated steam may be brought into contact with livestock manure in which siliceous plant-based organic material and granular siliceous shale have been mixed. [Effects of the Invention]

[0018] According to the livestock manure treatment method of the present invention, livestock manure can be treated efficiently and simply, and according to the soil improvement composition production method of the present invention, a soil improvement composition can be obtained by efficiently and simply treating livestock manure. [Brief explanation of the drawings]

[0019] [Figure 1]FIG. 1 is a flow diagram of an embodiment of a livestock manure treatment method. [Figure 2] FIG. 10 is a flow diagram of another embodiment of a livestock manure treatment method. [Figure 3] FIG. 10 is a flow diagram of another embodiment of a livestock manure treatment method. [Figure 4] 1 is a graph showing the pore distribution curve of the raw material, siliceous shale. [Figure 5] 1 is an explanatory diagram of a livestock manure treatment facility according to an embodiment. [Figure 6] FIG. 2 is a schematic perspective view of a mixing and granulating apparatus. [Figure 7] FIG. 2 is a schematic perspective view of a contact treatment device. [Figure 8] FIG. 10 is an explanatory diagram of the arrangement of supply pipes. [Figure 9] FIG. 2 is a cross-sectional schematic view of the cooling and drying device. [Figure 10] FIG. 2 is a schematic perspective view of a contact treatment device. [Figure 11A] This is an optical microscope image of treated feces and urine (observation magnification: 10x). [Figure 11B] This is an optical microscope image of treated feces and urine (observation magnification: 10x). [Figure 11C] This is an optical microscope image of treated feces and urine (observation magnification: 10x). [Figure 11D] This is an optical microscope image of treated feces and urine (observation magnification: 10x). [Figure 11E] This is an optical microscope image of treated feces and urine (observation magnification: 10x). [Figure 11F] This is an optical microscope image of treated feces and urine (observation magnification: 40x). [Figure 11G] This is an optical microscope image of treated feces and urine (observation magnification: 40x). [Figure 11H] This is an optical microscope image of treated feces and urine (observation magnification: 40x). [Figure 11I] This is an optical microscope image of treated feces and urine (observation magnification: 40x). [Figure 11J]This is an optical microscope image of treated feces and urine (observation magnification: 40x). DETAILED DESCRIPTION OF THE INVENTION

[0020] [First embodiment] As shown in FIG. 1, a livestock manure treatment method according to one embodiment of the present invention treats livestock manure 11 to produce treated manure 13A. The treated manure 13A can be used as a soil-improving composition for improving soil, so this livestock manure treatment method also serves as a method for producing a soil-improving composition. The livestock manure 11 may be manure from livestock such as cows, pigs, horses, sheep, or goats, or from poultry such as chickens, turkeys, ducks, or geese, or a mixture of at least two of these. In this example, the object to be treated is only the livestock manure 11, and no substances other than the livestock manure 11 have been intentionally added to the livestock manure 11. Because the livestock manure 11 to be treated is unadded manure to which no substances other than the livestock manure 11 have been intentionally added, the livestock manure 11 can be treated even if it contains a small amount of organic soil or bedding (for example, a volumetric content of at most 1%) when collected from a livestock facility such as a cowshed or a poultry facility such as a chicken farm.

[0021] The livestock manure 11 is preferably undried livestock manure because of its high moisture content. Because the livestock manure 11 has a higher moisture content than dried livestock manure, the Maillard reaction is suppressed in the contact treatment step S2, resulting in the treated manure 13A being produced as smaller particles, resulting in a treated manure 13A with a higher nitrogen content. As a result, the treated manure 13A is more easily soluble (including dispersible) in water. Being more easily soluble means that the treated manure 13A dissolves in a shorter time, dissolves more, and disperses with reduced sedimentation. Because the treated manure 13A is produced as smaller particles, even if it is formed into granules as described below, each granule is composed of extremely small particles with excellent solubility. For example, when used as a soil improving composition, the treated manure 13A mixes with soil more quickly and can be dissolved in water for use as a liquid fertilizer. This contributes to more effective availability to plants, and is expected to improve plant growth-promoting effects. The nutrient solution can also be used as a nutrient solution that is applied directly to plants without going through soil, for example, as a foliar spray solution for plant leaves or as a nutrient solution for application to roots.

[0022] The moisture content of the livestock manure 11 is not particularly limited, but is preferably at least 30% from the viewpoint of more reliably suppressing the Maillard reaction in the contact treatment step S2. The moisture content of the livestock manure 11 is more preferably at least 35.2%, and even more preferably at least 40.5%.

[0023] The livestock manure treatment method includes a granulation step S1, a contact treatment step S2, and a cooling and drying step S3. At least one of the granulation step S1 and the cooling and drying step S3 may be omitted, but it is preferable that they are included, as in this example. The cooling and drying step S3 may be replaced by dividing the process into a cooling step and a drying step, with one step preceding the other, or by one step being performed within the other step.

[0024] In the granulation step S1, the livestock manure 11 to be subjected to the contact treatment step S2 is formed into granules. This improves the handling (ease of handling) in the subsequent steps, such as the contact treatment step S2 to the cooling and drying step S3, and the treated manure 13A is obtained in a granular form, which is easier to handle than a powder with a smaller particle size. For example, the treated manure 13A is easy to remove from a container such as a bag or can, and when used as a soil improving composition, it is less likely to float in the air than a powder when mixed into the soil, making it easier to work with. Since the granulation step S1 forms the manure into granules, a pulverization process may be included to obtain the granules. For example, in the second and third embodiments described below, rice husks or siliceous shale may be pulverized in the granulation step S1. If the granulation step S1 is not performed, the treated manure 13A is obtained in a powder form.

[0025] The granulation step S1 can be performed using, for example, a known granulation device that forms fertilizer into granules (pellets, discs, spheres, etc.); the granulation device is not particularly limited. However, since livestock manure 11 contains moisture, a granulation device capable of granulating a water-containing material to be treated can be used, such as an extrusion pelletizer or a pan granulation device, the details of which will be described later. Examples of extrusion pelletizers include those that extrude the material to be treated (livestock manure 11 in this example) from a kneading section to form strands, and then cut these strands to form cylindrical pellets, and those that cut the material emerging from the kneading section one after another at the outlet to form cylindrical or disc-shaped pellets. Alternatively, a sieve device equipped with a mesh-shaped, generally horizontally arranged net member and a pressing member with a flat lower surface can also be used as the granulation device. In this sieving device, the material to be treated is placed on a net member and pressed from above by a pressing member, causing the material to pass through the openings in the net member and be formed into granules.

[0026] Furthermore, since the moisture content and softness of livestock manure 11 vary depending on the type of livestock or poultry, it is preferable to determine the granulation device to be used taking into consideration the moisture content and softness. For example, a sieving device is used for livestock manure 11 with a moisture content of 30% or more but less than 40%, and an extrusion pelletizer is used for livestock manure 11 with a moisture content of 40% or more. In this example, a sieving device is used for chicken manure with a moisture content of 35.2%, and an extrusion pelletizer is used for pig manure with a moisture content of 40.5%.

[0027] The size and shape of the granules formed in the granulation step S1 are not particularly limited, and the size is preferably, for example, 1 mm or more, with this particle size being the smallest part of the particle diameter. In this example, chicken manure is formed into granules with a particle size of 1 mm or more and 4.74 mm or less, and swine manure is formed into pellets with a diameter of 6 mm and a length of 10 mm. Note that the granulation step S1 may include a removal step in which, after forming the granules, particles smaller than the desired size are removed using a sieve. In this example, a removal step is included in which powder with a particle size less than 1 mm is removed, and the sieve used has an opening of 1 mm.

[0028] In the contact treatment step S2, superheated steam is brought into contact with livestock manure 11. The contact treatment step S2 may be carried out using either a batch type contact treatment device or a continuous type contact treatment device. Details of the contact treatment step S2 will be described later using another drawing.

[0029] The cooling and drying step S3 includes a cooling step for cooling the treated material that has been heated in the contact treatment step S2, and a drying step for drying the treated material that has been subjected to the contact treatment step S2. Drying reduces the moisture content, making the resulting treated feces and urine 13 lighter, facilitating transportation and handling, and suppressing deterioration during storage. The treated material may be dried under heat; for example, in this example, drying is performed using an apparatus set at 100°C. When drying under heat, it is preferable to cool the treated material after drying to, for example, room temperature (approximately 25°C) in order to suppress condensation on the surface of the treated material. Details of the cooling and drying step S3 will be described later using another drawing. If the cooling and drying step S3 is not performed, the treated material produced in the contact treatment step S2 can be used as a treated feces and urine product, and this treated feces and urine product can be used as a soil amendment composition, etc. This also applies to the second and third embodiments described below.

[0030] [Second embodiment] Similar to the first embodiment, the livestock manure treatment method of the second embodiment of the present invention treats livestock manure 11 to produce a treated manure product. In this example, as shown in FIG. 2, a manure mixture 17, in which livestock manure 11 is mixed with rice husks 15, is treated to produce a treated manure product 13B. Livestock manure 11 is mixed with organic materials used as bedding in a livestock barn or poultry house, such as a chicken coop, and this example treats the manure mixture 17. If the livestock manure 11 contains rice husks 15 to be disposed of, for example, the rice husks 15 may be added to the livestock manure 11 and mixed to produce the manure mixture 17. The proportion of the mass M12 of the rice husks 15 in the manure mixture 17 is not particularly limited. Like the treated manure product 13A, the resulting treated manure product 13B can also be used as a soil modifying composition for modifying soil, so the livestock manure treatment method of this example also serves as a method for producing a soil modifying composition.

[0031] The rice husks 15 are the outer husks removed from rice grains (hulled rice) during threshing. The rice husks 15 may contain, in addition to the outer husks, materials removed during hulling. The rice husks 15 are an example of a plant-based silicate organic material containing silicate Si(OH)4. Examples of plant-based silicate materials include grasses other than rice, some ferns (e.g., club moss), and some horsetails. Dried versions of these can also be used as plant-based silicate organic materials. However, rice husks 15 are preferred because they are easily available, including in large quantities, and many people are familiar with using them, as they are used as bedding in livestock sheds such as cow sheds and poultry facilities such as chicken farms. Furthermore, rice husks 15 are preferred as plant-based silicate organic materials from the perspective of effectively utilizing a large amount of rice husks 15.

[0032] The livestock manure treatment method of this example is the same as that of the first embodiment, except that the object to be treated is a manure mixture 17. That is, it has a granulation step S1, a contact treatment step S2, and a cooling and drying step S3, and at least one of the granulation step S1 and the cooling and drying step S3 may be omitted. Also, it differs from the first embodiment in that the obtained treated manure 13B contains decomposition products of rice husks 15.

[0033] [Third embodiment] Similar to the first and second embodiments, the livestock manure treatment method according to the third embodiment of the present invention treats livestock manure 11 to produce treated manure. In this example, as shown in Figure 3, a siliceous shale mixture 21, in which livestock manure 11 is mixed with rice husks 15 and siliceous shale 19, is treated to produce treated manure 13C.

[0034] The livestock manure treatment method includes a granulation step S1, a contact treatment step S2, a cooling and drying step S3, a crushing step S11, a siliceous shale mixing step S12, and a hydration step S13. The granulation step S1 may also include the hydration step S13, and granulation can be performed while adding water. The manure treatment product 13C obtained in this example differs from the manure treatment product 13B in that it contains siliceous shale 19 that has been reduced by contact treatment with superheated steam.

[0035] In the crushing step S11, for example, granular siliceous shale 19 having a block shape or a particle size of 1 mm or more is crushed into powder to produce powdered siliceous shale 19A. Siliceous shale 19 and powdered siliceous shale 19A differ only in size, but have the same components and pore (void) structure. If powdered siliceous shale 19A is available, crushing step S11 is unnecessary. Diatomaceous earth other than siliceous shale may be used instead of siliceous shale 19 and powdered siliceous shale 19A.

[0036] The particle size of the powdered siliceous shale 19A is not particularly limited. In this example, by using powdered siliceous shale 19A with a particle size of less than 1 mm, i.e., fine particles less than 1 mm, when added to the feces and urine mixture 17, for example, in the siliceous shale mixing step S12 described below, some of the added powdered siliceous shale 19A floats slightly upward and floats in the air. The deodorizing function of the siliceous shale 19 and the powdered siliceous shale 19A reduces the odor emitted from the feces and urine mixture 17. Thus, it is preferable that the powdered siliceous shale 19A has a particle size such that some of the added powdered siliceous shale 19A floats upward when added to the feces and urine mixture 17. Furthermore, by crushing the siliceous shale 19 into powdered siliceous shale 19A, the contact area with the feces and urine mixture 17 is increased, thereby further reducing the odor of the feces and urine mixture 17 when mixed with the feces and urine mixture 17. As described above, powdered siliceous shale 19A is preferable because it has a greater deodorizing effect on feces and urine mixture 17 than siliceous shale 19 before being crushed, and it is also preferable to crush siliceous shale 19 into powder in crushing step S11 from the viewpoint of mixing it with feces and urine mixture 17 more quickly and more uniformly in siliceous shale mixing step S12. The particle size of powdered siliceous shale 19A may be non-uniform, i.e., may vary from particle to particle.

[0037] The siliceous shale mixing step S12 is intended to reduce the odor of the manure mixture 17, to polish or crush the rice husks 15 contained in the manure mixture 17, and to obtain a siliceous shale mixture 21 containing powdered siliceous shale 19A. In the siliceous shale mixing step S12, the manure mixture 17 and the powdered siliceous shale 19A are mixed to obtain the siliceous shale mixture 21. The mixing is preferably carried out by stirring, for example, until the mixture is homogenous, with the powdered siliceous shale 19A dispersed throughout.

[0038] In the siliceous shale mixing step S12, the feces and urine mixture 17 and the powdered siliceous shale 19A may be added to one another. In this example, the powdered siliceous shale 19A is added to the feces and urine mixture 17. By adding the powdered siliceous shale 19A to the feces and urine mixture 17, a portion of the powdered siliceous shale 19A slightly floats and floats up during the addition, as described above, which is more effective in reducing odor from the feces and urine mixture 17 than when the feces and urine mixture 17 is added to the powdered siliceous shale 19A. When adding the powdered siliceous shale 19A to the feces and urine mixture 17, the entire amount of the powdered siliceous shale 19A to be mixed may be added at once and stirred, or it may be added in multiple portions, with the feces and urine mixture 17 and the powdered siliceous shale 19A being stirred after each addition.

[0039] As described above, the powdered siliceous shale 19A is an extremely small particle, so its contact area with the manure mixture 17 is much larger than that of the siliceous shale 19 before crushing, and the powdered siliceous shale 19A is dispersed throughout the siliceous shale mixture 21, thereby reliably reducing the odor of the manure mixture 17. When mixed with the powdered siliceous shale 19A, which is harder than the rice husks 15, the rice husks 15 are ground or crushed, which destroys the structure, forming voids between the structures and causing some of the structure to peel off. This allows the rice husks 15 to reliably and quickly absorb water in the subsequent hydration step S13.

[0040] The mass M19 of the powdered siliceous shale 19A to be mixed with the manure mixture 17 is preferably in the range of 0.03 × M17 or more and 0.20 × M17 or less, where M17 is the mass of the manure mixture 17. When the mass M19 is 0.03 × M17 or more, the odor of the manure is more reliably reduced than when it is less than 0.03 × M17, and the structure of the rice husks 15 is broken down, further promoting the water absorption of the rice husks 15 in the water-containing step S13. While the mass M19 may be greater than 0.20 × M17, there is no particular advantage to exceeding 0.20 × M17 compared to 0.20 × M17. A mass M19 of 0.20 × M17 or less sufficiently reduces the odor and breaks down the structure of the rice husks 15. The mass M19 is more preferably in the range of 0.04×M17 or more and 0.15×M17 or less, and even more preferably in the range of 0.05×M17 or more and 0.10×M17 or less.

[0041] The water-containing step S13 is intended to promote the destruction of the layered structure of the rice husks 15 contained in the siliceous shale mixture 21 and the decomposition of the rice husks 15 while suppressing the Maillard reaction in the subsequent contact treatment step S2. In the water-containing step S13, liquid water 24 is added to the siliceous shale mixture 21. Specifically, the water 24 is allowed to penetrate the pores of the porous powdered siliceous shale 19A and the rice husks 15. By adding water 24 to the powdered siliceous shale 19A, the destruction of the layered structure of the rice husks 15 and the decomposition of the rice husks 15 in the contact treatment step S2 are promoted while suppressing the Maillard reaction. The water 24 is not particularly limited, and its cleanliness may be considered depending on the intended use of the treated feces and urine 13B. In this example, considering that the treated feces and urine 13B will be used as a soil amendment composition, water of a clean enough level for human consumption is used, such as tap water or deionized water. Other examples of the water 24 include distilled water, ion-exchanged water, and RO water purified by an RO (reverse osmosis) membrane.

[0042] As in the first and second embodiments, the granulation step S1 is for forming the material to be treated into granules for the contact treatment step S2. The material is a siliceous shale mixture 21 containing water. When the hydration step S13 is performed before the granulation step S1 as shown in FIG. 3, the granulation step S1 forms the siliceous shale mixture 21 containing water into granules. When the hydration step S13 is performed within the granulation step S1 as described above, the siliceous shale mixture 21 is granulated while being hydrated. If the hydration step S13 is too high, for example, and granulation is difficult, some drying may be performed in the granulation step S1. By forming the granular mixture 22 in this way, the handling properties (ease of handling) are improved due to the uniformity of the treatment in the subsequent steps, and the quality of the resulting treated feces and urine 13C is improved.

[0043] The contact treatment step S2 is for converting the granular mixture 22 containing livestock manure 11 into treated manure 13C that can be used, for example, as a soil improving composition or organic material. In the contact treatment step S2, the granular mixture 22 is brought into contact with superheated steam 23 (see FIG. 5), thereby obtaining treated manure 13C.

[0044] In the cooling and drying step S3 in this example, the granular mixture 22 that has been subjected to the contact treatment step S2 is cooled and dried.

[0045] The raw material, siliceous shale 19, will now be described. The pores in siliceous shale 19 are classified by the IUPAC (International Union of Pure and Applied Chemistry) as follows: micropores (pores with a pore diameter of 2 nm or less), mesopores (pores with a pore diameter of 2 nm to 50 nm), and macropores (pores with a pore diameter of 50 nm or more). Based on this classification, siliceous shale 19 has all of the following: micropores, mesopores, and macropores, all of which coexist. Based on the pore distribution curves described below, it can be inferred that mesopores are formed on the inner wall surfaces defining macropores, and that micropores are formed on the inner wall surfaces defining mesopores. Note that mesopores and micropores may exist independently in siliceous shale 19, and some micropores may also be formed on the inner wall surfaces of macropores.

[0046] Treated manure 13C is obtained using powdered siliceous shale 19A obtained by crushing siliceous shale 19, and no special processing was performed during production to desorb the components of powdered siliceous shale 19A. Therefore, the powdered siliceous shale 19A contained in treated manure 13C has roughly the same pore radius and pore distribution as the raw material siliceous shale 19. It should be noted that siliceous shale may have microorganisms (bacteria, fungi, viruses, etc.) attached to the inner walls defining the pores, and the pore size of siliceous shale cannot be measured taking into account the presence or absence of these attachments. Therefore, there may be very slight differences between the pore size measurements of the raw material siliceous shale 19 and the pore size measurements of the porous material component derived from powdered siliceous shale 19A contained in treated manure 13C. However, the contact treatment with superheated steam described below removes attached substances such as microorganisms, but does not remove the components of the siliceous shale 19 itself, so the size of the pores in the porous material components can be considered to be the same as the size of the pores in the raw material siliceous shale 19.

[0047] The pore radius of the raw material siliceous shale 19 is at most 10 μm. As shown in FIG. 4, in the pore distribution curve showing the relationship between pore radius and pore volume, the pore radius of the siliceous shale 19 is in the first range of 0 nm to 10 nm, with a maximum of 0.02 cm. 3 The first peak exceeds / g, and the second range is 0.02 cm in the range of 100 nm to 10 μm. 3 / g. Therefore, the powdered siliceous shale 19A, which is a porous material component contained in the treated manure 13C, also has a pore radius of 10 μm at most. The pore distribution curve shown in Figure 4 is data for the press-molded siliceous shale 19, but the Horonobe Geoenvironment Research Institute (public) has reported that press-molding does not affect the pore distribution, which consists of macropores, mesopores, and micropores. The vertical axis of Figure 4 is the pore volume, and the horizontal axis is the pore radius, which are expressed in logarithmic scale.

[0048] Geographically, siliceous shale is classified as a type of diatomaceous earth, and it is generally known that diatomaceous earth also has pores. Wakkanai siliceous shale and the main diatomaceous earths produced in Japan each have the pore characteristics shown in Table 1. The "average specific surface area of ​​diatomaceous earth" in Table 1 is the average value (av1) of the specific surface area x1 of four types of diatomaceous earth: Akita diatomaceous earth, Ishikawa diatomaceous earth, Okayama diatomaceous earth, and Oita diatomaceous earth. The "ratio of specific surface area to the average diatomaceous earth" is calculated using the formula x1 / av1. The "average pore volume of diatomaceous earth" in Table 1 is the average value (av2) of the pore volume x2 of the four types of diatomaceous earth. The "ratio of pore volume to the average diatomaceous earth" is calculated using the formula x2 / av2. The "average pore radius of diatomite" in Table 1 is the average value of the average pore radius x3 for each of the four types of diatomite (av3). The "ratio of average pore radius to the average diatomite" is calculated using the formula x3 / av3. Table 1 is an excerpt from a report submitted to Horonobe Gravel Co., Ltd. (now Cerea Co., Ltd.) by the Horonobe Geo-Environment Research Institute, a public interest incorporated foundation, after the Horonobe Gravel Co., Ltd. (now Cerea Co., Ltd.) requested the Hokkaido Science and Technology Center (Horonobe Geo-Environment Research Institute) to analyze molded siliceous shale. The Wakkanai Formation hard shale in Kamihoronobe, Horonobe Town, has the basic properties shown in Table 2. Table 2 is based on the above-mentioned report from the Horonobe Geo-Environment Research Institute. The "Wakkanai Formation siliceous shale" in Table 1 and the "Kamihoronobe Hard Shale" in Table 2 refer to the Wakkanai Formation hard shale in Kamihoronobe, Horonobe Town, and is the siliceous shale 19 used in this example. However, the siliceous shale used as the raw material is not limited to the siliceous shale 19 of this example. For example, diatomaceous earth and siliceous shale that do not have the second peak may be used, or diatomaceous earth and siliceous shale that have a peak in the first range of pore radii greater than 0 nm and less than 10 nm, but the peak is less than 0.02 cm. 3 Diatomaceous earth and siliceous shale having a pore size less than 1 / g may also be used.

[0049] [Table 1]

[0050] [Table 2]

[0051] Although the siliceous shale 19 is not particularly limited, it is preferable to use the Wakkanai Formation siliceous shale mentioned above because it has the above-mentioned pores. The physical properties of the siliceous shale 19 used in this example are shown in Table 3. The physical property values ​​shown in Table 3 are a summary of the results of analysis by the Hokkaido Industrial Research Institute and the Hokkaido Central Agricultural Experiment Station (now part of the Hokkaido Research Organization, a local independent administrative institution).

[0052] The "water absorption rate" in Table 3 is the result of analysis conducted at the Hokkaido Industrial Research Institute. The analysis method involved drying the sample, allowing it to absorb water for 24 hours, removing the surface moisture, and then measuring the sample's weight. The sample was then dried for 8 hours in a dryer set at 150°C, and the weight of the dried sample was measured. The water absorption rate was calculated from the weight before and after drying. There were two types of samples: one with a particle size of 1 mm and one with a particle size of 8 mm. The water absorption rate for the 1 mm particle size was the average value of the water absorption rate of two samples, and the water absorption rate for the 8 mm particle size was the average value of the water absorption rate of four samples.

[0053] The "moisture absorption rate" in Table 3 is the result of analysis conducted by the Hokkaido Prefectural Industrial Research Institute (Industrial Research Institute Result No. 193123). The test method involved precisely weighing 1g of bone-dry sample into a weighing bottle, placing it in a constant temperature, constant humidity chamber at a constant temperature of 25°C, and changing the humidity between 90% RH and 50% RH every 24 hours. The mass of the sample in each atmosphere was measured, and the moisture absorption rate was calculated using the following formula. Moisture absorption rate (%) = 100 x moisture absorption amount / absolute dry mass

[0054] The "base exchange capacity" in Table 3 is the result of analysis conducted by the Hokkaido Central Agricultural Experiment Station (No. 1-42). The analytical method is based on "Diagnostic Criteria for Soil and Crop Nutrition - Analytical Method (Revised Edition)" (Hokkaido Agriculture Department, Hokkaido Central Agricultural Experiment Station, 1992). This analytical method (soil analysis method) uses ammonium acetate extraction - Schöllenberger method - formol titration.

[0055] The "available moisture content" in Table 3 is the result of analysis conducted by the Hokkaido Central Agricultural Experiment Station (Chuo No Kanpo No. 1-37). The analytical method is based on the "Diagnostic Criteria for Soil and Crop Nutrition - Analytical Method (Revised Edition)" (Hokkaido Prefectural Agriculture Department, Hokkaido Central Agricultural Experiment Station, 1992). In this analytical method (soil analysis method), the actual sample was placed in a 100 ml soil sampling tube, saturated with water, and then the gas phase was measured using a three-phase meter. Subsequently, measurements were made at the pF3 stage using the centrifuge method. Finally, the soil was thermally dried at 105°C, and the moisture content was measured. The moisture content at pF0 was calculated by adding the moisture content at saturated water level and the proportion of the gas phase.

[0056] [Table 3]

[0057] Treated manure 13C can be obtained, for example, by livestock manure treatment equipment (hereinafter simply referred to as "treatment equipment") 31 shown in Figure 5. Treatment equipment 31 is used to treat livestock manure 11 to obtain treated manure 13C, and is also a soil improving composition production equipment that produces a soil improving composition from livestock manure 11.

[0058] The processing facility 31 includes a pulverizer 33, a mixer / granulator 34, a superheated steam contactor (hereinafter simply referred to as the "contactor") 35, and a cooling / drying device 36. The pulverizer 33 is used for the pulverization step S11 (see FIG. 3), which pulverizes the siliceous shale 19 into powdered siliceous shale 19A. In this example, the siliceous shale 19 is in the form of irregular chunks as mined and may be large, for example, with a diameter exceeding 100 mm. If powdered siliceous shale 19A is available, the pulverization step S11 is unnecessary, as described above, and therefore the pulverizer 33 can be omitted. The size of the powdered siliceous shale 19A can be adjusted by adjusting the degree of pulverization of the siliceous shale 19. Furthermore, if the mixer / granulator 34 has the function of pulverizing the siliceous shale 19 into powder, the pulverizer 33 may not be used. In this example, the siliceous shale 19 is pulverized in the mixer / granulator 34 without the pulverizer 33.

[0059] The crushing device 33 is not particularly limited as long as it can crush the siliceous shale 19, and commercially available crushing devices may be used. Depending on the processing volume (amount to be crushed) of the siliceous shale 19 and the target particle size of the powdered siliceous shale 19A, a combination of at least two types of crushers (roller mills, jet mills, high-speed rotary crushers, container-driven mills, etc.) and crushers (jaw crushers, bucket crushers, dilute tri-crushers, cone crushers, double-roll crushers, impact crushers, etc.) may be used. For example, an impact-type and biaxial-type crusher manufactured by HORAI CORPORATION can be combined with a high-speed rotary crusher to crush the material while also adjusting the particle size.

[0060] The mixing and granulating apparatus 34 is used for the siliceous shale mixing step S12, the moisture-containing step S13, and the granulating step S1, and a granular mixture 22 is obtained from livestock manure 11, rice husks 15, powdered siliceous shale 19A, and water 24. In this example, as described above, the pulverizing step S11 is also performed in this mixing and granulating apparatus 34. Depending on the type of livestock manure 11, the livestock manure 11 may be dried to a pulverizable degree and then pulverized into granules. In the granulating step S1 performed in the mixing and granulating apparatus 34, the manure 11 is formed into pellets, spheres, or other granules, as described above.

[0061] The contact treatment device 35 is for the contact treatment step S2. There are batch and continuous types of contact treatment devices, and the contact treatment device 35 is of the batch type. The contact treatment device 35 is composed of a contact treatment section 37, a superheated steam supply section 38, and the like. The superheated steam supply section 38 is for supplying superheated steam 23 (see FIG. 7) to the contact treatment section 37 and is connected to the contact treatment section 37. The contact treatment section 37 brings the superheated steam 23 supplied by the superheated steam supply section 38 into contact with the granular mixture 22 containing water 24, thereby raising the temperature of the granular mixture 22. As a result, the rice husks 15 and livestock manure 11 contained in the granular mixture 22 decompose, and the treated manure product 13C is produced in a state in which the Maillard reaction is suppressed.

[0062] The superheated steam supply unit 38 is provided in the contact treatment device 35, but the superheated steam supply unit 38 may be an external device provided outside the contact treatment device 35 as long as it is connected to the contact treatment unit 37. Details of the contact treatment device 35 will be described later using another drawing.

[0063] The cooling and drying device 36 is used for the cooling and drying step S3. A feature of the superheated steam treatment is that the temperature of each particle of the treatment object (in this example, the granular mixture 22) is raised so that the central temperature of each particle is high, and the particle contains water vapor immediately after treatment. Utilizing this state, the cooling and drying device 36 of this example efficiently reduces the moisture content by vacuum drying under reduced pressure and rapidly cools the material by generating heat of vaporization. This allows drying while suppressing a decrease in product temperature. The sterilization effect is maintained by preventing condensation after contact treatment. In this way, the cooling and drying device 36 is, in other words, a condensation prevention device. The cooling and drying step S3 of the first and second embodiments is also performed by this cooling and drying device 36. Details of the cooling and drying device 36 will be described later using another drawing.

[0064] As shown in Figure 6, one example of the aforementioned mixing and granulating device 34 includes a supply unit 40 that supplies the manure mixture 17 and powdered siliceous shale 19A, a pan 41 as a container for storing the manure mixture 17 and powdered siliceous shale 19A, a rotation mechanism 42, an angle adjustment mechanism 43, a water supply unit 44, and a recovery unit 45. The pan 41 is a circular container with an open top, and has a support plate 41a that supports the pan 41 at a predetermined inclination. The pan 41 is mounted on the support plate 41a so as to be rotatable in the circumferential direction. The surface of the support plate 41a opposite to the surface on which the pan 41 is mounted is fixed to a support rod 41b extending horizontally.

[0065] The rotation mechanism 42 has a motor (not shown) that rotates the pan 41, and a rotation controller (not shown) that switches the motor on and off and adjusts the rotation speed, and the motor is provided on the surface of the support plate 41a opposite to the surface on which the pan 41 is provided. The rotation controller controls the rotation and stopping of the pan 41 by switching the motor on and off, and adjusts the rotation speed of the pan 41 by adjusting the rotation speed of the motor.

[0066] The angle adjustment mechanism 43 rotates the support rod 41b in the circumferential direction around the axis of the support rod 41b as the rotation center, thereby adjusting the pan 41 to a predetermined tilt. The pan 41 is tilted to a predetermined angle by the angle adjustment mechanism 43, and rotates at a predetermined rotation speed by the rotation mechanism 42 in the tilted position.

[0067] A nozzle 47 that dispenses water 24 (see FIG. 3) is disposed above the pan 41, and the nozzle 47 is fixed to the support plate 41a by a fixing member 47a. By being fixed to the support plate 41a, the nozzle 47 tilts integrally with the pan 41 provided on the support plate 41a. A water passage (not shown) that guides water is formed inside the fixing member 47a, and the water supply unit 44 is connected to the nozzle 47 via the fixing member 47a and sends the water 24 to the nozzle 47. As a result, the water 24 is supplied into the pan 41 that is rotating in a tilted position, and the water-containing step S13 can be carried out. The nozzle 47 is not particularly limited, and may be a spray nozzle that dispenses water 24 in the form of droplets or a flow nozzle that dispenses water in the form of a stream.

[0068] A scraper 48 is provided inside the pan 41 to scrape the excrement mixture 17 and powdered siliceous shale 19A adhering to the inner wall of the pan 41. The scraper 48 is fixed to the support plate 41a by a fixing member 48a, similar to the nozzle 47. By being fixed to the support plate 41a, the scraper 48 tilts integrally with the pan 41 mounted on the support plate 41a. This allows the excrement mixture 17 and powdered siliceous shale 19A adhering to the inner wall of the pan 41 while it is rotating in a tilted position to be scraped off. This allows the excrement mixture 17 and powdered siliceous shale 19A to be mixed more quickly and uniformly, and also facilitates the water 24 to be distributed more evenly and quickly throughout the pan. Because the scraper 48 is designed to scrape the excrement mixture 17 and powdered siliceous shale 19A from the inner wall of the pan 41, it may be provided so as to scrape not only the inner sidewalls but also the inner bottom surface of the pan 41, as shown in FIG. 6 .

[0069] The manure mixture 17 and powdered siliceous shale 19A are continuously supplied to a rotating, tilted pan 41 by a supply unit 40, and water 24 is supplied by a water supply unit 44. The manure mixture 17 and powdered siliceous shale 19A are mixed while wet and rolling, and the particles grow to a predetermined particle size. Because the pan 41 is rotating, centrifugal force causes the particles to grow, gradually reducing the rolling path within the pan 41. When the particles reach a predetermined particle size, they are discharged from the lower edge of the tilted pan 41 as a granular mixture 22. By adjusting the rotation speed and tilt of the pan 41, the rolling path and the timing of particle discharge can be adjusted, resulting in a granular mixture 22 of the desired particle size. The temperature of the supplied water 24 is not particularly limited; in this example, it is set to room temperature (approximately 25°C).

[0070] The mass of the powdered siliceous shale 19A to be added to the manure mixture 17 is not particularly limited, but when the mass of the manure mixture 17 is M17, it is preferable that the mass of the granular mixture 22 be in the range of (0.05 x M17)% or more and (0.10 x M17)% or less.

[0071] The moisture content of the granular mixture 22 is not particularly limited, but is preferably in the range of 20% to 45%. A moisture content of 20% or more more reliably suppresses the Maillard reaction in the contact treatment step S2, and more reliably promotes the destruction of the layer structure of the rice husks 15 and the decomposition of the rice husks 15, compared to when the moisture content is lower than 20%. Since there is no significant difference between a moisture content higher than 45% and a moisture content of 50% is considered sufficient. The moisture content is more preferably in the range of 30% to 45%, and even more preferably in the range of 35% to 45%. The moisture content (unit: %) is calculated by {M22 - (M17 + M19A)} / M17, where M17 is the mass of the manure mixture 17, M19A is the mass of the powdered siliceous shale 19A, and M22 is the mass of the granular mixture 22.

[0072] The recovery section 45 is disposed below the inclined pan 41 and recovers the formed granular mixture 22. For example, a container may be disposed below the recovery section 45, and the granular mixture 22 may be guided into the container.

[0073] A known pan granulator can be used as the mixer / granulator 34, and a commercially available pan granulator may also be used. In this example, the mixer / granulator 34 performs the siliceous shale mixing step S12, the hydration step S13, and the granulation step S1. By changing the timing at which the supply of water 24 is started, the siliceous shale mixing step S12 and the hydration step S13 can be performed simultaneously, or the hydration step S13 can be performed after the siliceous shale mixing step S12. In addition, by adjusting the attitude of the pan 41, i.e., the timing at which the supply of water 24 is started and the timing at which the pan 41 is tilted, the timing of the hydration step S13 and the granulation step S1 can be adjusted. For example, the water impregnation step S13 can be carried out by supplying water 24 in a non-inclined position, and then the pan 41 can be tilted partway through the water impregnation step S13 to carry out the water impregnation step S13 and the granulation step S1 in parallel, or the pan 41 can be tilted after the water impregnation step S13 is completed to carry out the granulation step S1 after the water impregnation step S13. Also, if the livestock manure 11 contains enough moisture to suppress the Maillard reaction in the contact treatment step S2, the water impregnation step S13 does not need to be carried out, and in that case the nozzle 47 and the water supply unit 44 may be omitted. Furthermore, as described above, when the livestock manure 11 is to be somewhat dried in the granulation step S1, the drying may be promoted by, for example, blowing dry air onto the manure 11, and then granulation may be carried out.

[0074] Granulation methods include wet granulation and dry granulation, and either method can be used for the granulation step S1. The method in this example is a pan granulation method, which is a wet granulation method. Wet granulation methods include, for example, rolling granulation and extrusion granulation, and pan granulation is one type of rolling granulation. Rolling granulation involves wetting raw material powders using a liquid such as water, creating liquid bridges between the powders, which then adhere and bond to form particles. In addition to pan granulation, other rolling granulation methods include drum granulation, in which powder and liquid such as water are added from the top of a rotating, tilted cylindrical drum, and the mixture is rolled to form granules. Extrusion granulation involves adding a granulation accelerator and liquid such as water to the powder, mixing and kneading the mixture, and then extruding it through a perforated plate using a screw, plunger, roller, etc., and cutting it to a specific length using a cutter to form cylindrical granules.

[0075] The granulation step S1 can be carried out using other rolling granulation methods such as drum granulation, and extrusion granulation. Dry granulation is a method of forming powder into granules without adding liquid. When poultry manure, which has a high moisture content and viscosity, is used as livestock manure 11, it is dried to about 30% moisture and then granulated into irregular shaped granules using a grinder such as a pin mill. Another method is briquette granulation, in which a die cavity serving as a mold is formed in a roll and the powder that has entered therein is compressed and solidified under high pressure. High-pressure molding is not used in this example because it can result in uneven organic matter decomposition in the subsequent contact treatment process.

[0076] The granulation step S1 may be performed by dry granulation of the siliceous shale mixture 21 containing water 24. However, it is preferable to set the moisture content of the siliceous shale mixture 21 to at least 40% in order to ensure reliable granulation, and it is more preferable to maintain the moisture content at 40% or higher during the granulation step S1. However, the moisture content of the siliceous shale mixture 21 may be as high as possible.

[0077] The contact treatment device 35 will be described with reference to FIG. 7. The superheated steam supply unit 38 is an example of an apparatus that performs the contact treatment step S2 (see FIG. 3). This contact treatment device 35 is also used in the contact treatment step S2 of the first and second embodiments. In the first embodiment, the treatment target to be treated by this contact treatment device 35 is livestock manure 11, and in the second embodiment, it is a manure mixture 17. The contact treatment device 35 includes a steam generation unit 51 that generates superheated steam 23 from liquid water, a valve 52, and a controller 53 that controls the steam generation unit 51 and the valve 52. Liquid water is supplied to the steam generation unit 51, and the amount of superheated steam 23 generated and the temperature of the superheated steam 23 are adjusted under the control of the controller 53. The opening degree (including opening and closing) of the valve 52 is controlled by the controller 53, thereby adjusting the flow rate (supply flow rate) of the superheated steam 23 supplied to the contact treatment unit 37. In addition, the flow rate of superheated steam supplied to the contact treatment unit 37 may be adjusted by maintaining the valve 52 at a constant opening, for example, fully open, and adjusting the generation rate of superheated steam 23 in the steam generation unit 51.

[0078] The contact treatment section 37 includes a treatment section main body 56 and a support base 57 that supports the treatment section main body 56. The treatment section main body 56 includes three mounting devices 58A-58C on which the granular mixture 22 is placed, a plate-shaped support member 61 that supports the mounting devices 58A-58C, and a supply pipe 62 that supplies superheated steam 23 to the mounting devices 58A-58C. The three mounting devices 58A-58C are arranged at intervals in the vertical direction, i.e., the top-bottom direction, and are designated by the reference numerals 58A, 58B, and 58C from bottom to top. In the following description, when the mounting devices 58A-58C are not to be distinguished, they will be referred to as mounting devices 58. When multiple mounting devices 58 are arranged, it is preferable to install them at intervals in the vertical direction, as in this example. The number of mounting devices 58 is not limited and may be determined depending on the amount of the granular mixture 22 to be subjected to the contact treatment step S2, etc.

[0079] A pair of support members 61 are provided to support the mounting device 58. In this example, the support members 61 are provided on the support base 57 in order to position the supply pipe 62 so that the outlet 62о for the superheated steam 23, which is the tip opening of the supply pipe 62, is located below the mounting device 58A. The support members 61 are fixed to the support base 57 in an upright position, and protrusions 61a for supporting the mounting device 58 are formed on the opposing walls of the pair of support members 61. The protrusions 61a of the pair of support members 61 are set to the same height, and the mounting device 58 is supported in a state where it is floating above the floor surface while maintaining its posture. The shape of the protrusions 61a is not particularly limited, and in this example, they are formed to extend horizontally, and the mounting device 58 slides along the protrusions 61a, making it detachable from the support members 61. The direction in which the pair of support members 61 face each other is defined as the X direction.

[0080] The mounting device 58 is formed in a box shape with an open top and includes a mesh member 58a and a frame 58b that supports the mesh member 58a under tension. The mounting device 58 has external dimensions of 60 cm x 40 cm x 8 cm high, but the size of the mounting device 58 is not particularly limited. The frame 58b is in an upright position at an angle to the mesh member 58a, which allows it to be supported by the protrusions 61a and prevents the placed granular mixture 22 from falling off the mounting device 58. However, since the granular mixture 22 is less likely to fall when the amount of the placed granular mixture 22 is small, a horizontally flat frame similar to the mesh member 58a may be used instead of the frame 58b, depending on the possibility of falling.

[0081] The mesh member 58a holds the granular mixture 22 and guides the superheated steam 23 from below to the granular mixture 22. The mesh member 58a has a plurality of meshes as through-holes penetrating in the thickness direction, and each of these meshes allows the superheated steam 23 to pass through. In this example, the superheated steam 23 is discharged from the outlet 62o of the supply pipe 62 toward the lower surface of the mounting device 58A, as described below, and is guided to the upper surface side of the mounting device 58 by the meshes of the mesh member 58a. As a result, the superheated steam 23 comes into contact with the granular mixture 22 on the mesh member 58a. In this way, the mounting device 58 functions as a support member that supports the granular mixture 22 while the superheated steam 23 is in contact with it, and the meshes function as a guide path that guides the discharged superheated steam 23 to the granular mixture 22. Note that although the mesh member 58a is rectangular, it may have a shape other than a rectangle, for example, a circle.

[0082] The mesh member 58a is, for example, a net made of metal, and the frame 58b is also made of metal. There are no particular limitations on the metal, as long as it can maintain its shape without dissolving when in contact with the superheated steam 23. In this example, the mesh member 58a and the frame 58b are made of stainless steel. Because the mesh member 58a functions as a support member for the granular mixture 22, the mesh size is set to prevent the granular mixture 22 from passing through. If the granular mixture 22 does pass through, multiple mesh members 58a may be stacked in the thickness direction with the mesh sizes offset from each other, forming mesh sizes smaller than the mesh sizes of the multiple mesh members 58a. The mesh members 58a are set to a size that prevents the granulated feces and urine treatment material 11 in the first embodiment and the granulated feces and urine mixture 17 in the second embodiment from passing through.

[0083] The mesh member 58a is an example of a porous member, and the porous member is not limited to the mesh member 58a. For example, a porous plate obtained by forming a plurality of holes in a metal plate by, for example, punching may be used. Furthermore, a plurality of porous plates may be stacked in the thickness direction, or a porous plate and the mesh member 58a may be stacked in the thickness direction.

[0084] The supply pipe 62 is connected to the superheated steam supply unit 38, and is arranged so that the outlet 62о faces the lower surface of the mounting device 58. When a plurality of mounting devices 58 are provided as in this example, the supply pipe 62 may be installed below each of the plurality of mounting devices 58, with the outlet 62о facing the lower surface of each. However, since the superheated steam 23 flows upward when it is discharged from the outlet 62о, even if the supply pipe 62 is arranged only on the lowest mounting device 38A of the plurality of mounting devices 58, it is sufficient because the superheated steam 23 is guided to the granular mixture 22 on all of the mounting devices 58A to 58C.

[0085] In this example, two supply pipes 62 are provided below each of the pair of support members 61 so as to face each other in one of two directions intersecting on a horizontal plane, and each outlet 62о is located more inward than the support members 61 in the X direction (see FIG. 8 ). As a result, the superheated steam 23 emitted from the outlet 62о is guided upward between the pair of support members 61 by the plate-shaped support members 61. Therefore, the superheated steam 23 is guided and contacts the granular mixture 22 placed on the mounting devices 58A to 58C, and the delivered superheated steam 23 is used without waste in contact with the granular mixture 22. Furthermore, with this configuration, since the superheated steam is supplied upward from below, the temperature in the treatment space is likely to be uniform even for treatment objects containing a large amount of water, and the treatment object is more uniformly contacted and treated.

[0086] When the superheated steam 23 comes into contact with the granular mixture 22, the granular mixture 22 is heated all the way to the center of each grain, and the liquid water 24 (see Figure 5) contained in the granular mixture 22 turns into gaseous water, i.e., steam. By bringing the superheated steam 23 into contact with the granular mixture 22 containing water 24, the organic matter contained in the livestock manure 11 is decomposed into smaller molecules to an extent comparable to or greater than that of anaerobic fermentation, while the Maillard reaction is suppressed. This results in treated manure 13C having the same available components as conventional compost obtained over several months of fermentation, and can be used as a soil amendment composition.

[0087] In the following description, when there is no need to distinguish between treated manure 13A-13C, they will be referred to as treated manure 13. Commercially available compost is weakly alkaline. In contrast, the resulting treated manure 13 contains more than 50% water-soluble (dispersible) particles of several micrometers or less on a dry matter basis. When dissolved (or dispersed) in water, the resulting solution is weakly acidic and does not inhibit fertilizer absorption by crops, making it preferable. Furthermore, fermented livestock manure 11 exhibits weak alkalinity, which inhibits soil microbial activity. Its pH (hydrogen ion index) also inhibits fertilizer absorption by crop roots, requiring careful application rate and timing. In contrast, treated manure 13, in which the organic matter contained in livestock manure 11 has been depolymerized, became available in a model system with more than 70% of the material within 24 hours of application to soil, i.e., became water-soluble charged substances. Adding water to treated manure 13 with soil leachate has been shown to increase the respiration rate of soil microorganisms and decrease the redox potential.

[0088] The temperature of the processing space is more preferably in the range of 160°C to 400°C, even more preferably in the range of 170°C to 400°C, and particularly preferably in the range of 180°C to 250°C. The temperature of the processing space may be determined by detecting the temperature around the mounting table 58, and this detected temperature may be regarded as the temperature of the processing space. The temperature around the mounting table 58 can be detected, for example, by providing a temperature sensor (not shown) on the wall surface of the support member 61 on the side where the mounting tool 58 is installed.

[0089] The maximum flow rate of the superheated steam 23 generated in the steam generator 51 varies depending on the temperature of the superheated steam 23, and the degree of this change differs depending on the steam generator 51 used. For example, there is a steam generator 51 in which the flow rate increases by 1.5 times when the temperature of the superheated steam 23 drops by 100°C. In addition, flow rate adjustment has poor reproducibility. For this reason, the temperature of the superheated steam 23 and the amount of liquid water used to generate the superheated steam 23 are kept constant.

[0090] The temperature of the supplied superheated steam 23 depends not only on the temperature of the steam adjusted in the steam generator 51 but also on the flow rate adjusted by controlling the aperture of the valve 52. Therefore, it is preferable to more precisely control the temperature of the superheated steam 23 by controlling the aperture of the valve 52, as is done in this embodiment. Specifically, the aperture of the valve 52 may be adjusted by the controller 53 based on the detection result of the aforementioned temperature sensor (not shown) provided on the support member 61, for example. To increase the temperature of the superheated steam 23, the aperture of the valve 52 is adjusted to be smaller, and to decrease the temperature, the aperture is adjusted to be larger. The temperature of the superheated steam 23 may decrease between when it is generated in the steam generator 51 and when it reaches the mounting device 58. In such a case, the temperature of the superheated steam delivered from the steam generator 51 may be adjusted by the steam generator 51, taking into account the decrease in temperature.

[0091] In order to further improve the efficiency of contact treatment by contact with superheated steam 23 and to further promote the decomposition of organic matter and rice husks 15 in livestock manure 11, it is preferable to make the distance between the discharge outlet 62о and the lowest placing device 58A as small as possible.

[0092] From the viewpoint of supporting the mounting device 58, the plate-like support member 61 may be, for example, a columnar (rod-like) member in an upright position. In the case of such a columnar support member or when the support member 61 of this example is used, the space between the support members is open, so that the contact treatment space in which the superheated steam 23 and the granular mixture 22 (the livestock manure 11 in the first embodiment and the manure mixture 17 in the second embodiment) undergo contact treatment is an open system. The contact treatment space may also be a closed system separated from the external space. In the case of a closed system, for example, a box-shaped partition member may be used that surrounds the mounting device 58 and separates the contact treatment space from the external space. The bottom surface of this partition member may be open to allow the introduction of the superheated steam 23. The top surface of this partition member may be closed, but to promote the discharge of water vapor resulting from evaporation of the water 24, an opening may be provided in the top surface of the partition member, allowing the water vapor to be naturally discharged through the opening, or a suction mechanism for sucking gas into the opening may be provided to suck the water vapor. The position of the supply pipe 62 may be above the uppermost mounting device 58C among the mounting devices 58. However, it is preferable to arrange the supply pipe 62 below the mounting device 58A in order to more effectively discharge the water 24 contained in the granular mixture 22 to the outside of the treatment space when it evaporates.

[0093] The time for which the superheated steam 23 is in contact with the granular mixture 22, i.e., the time for the contact treatment step S2, is not particularly limited, but is preferably at least 10 minutes, which further promotes the decomposition of organic matter in the livestock manure 11 and the decomposition of the rice husks 15. The time for the contact treatment step S2 is more preferably at least 15 minutes.

[0094] 9, the cooling and drying device 36 cools and dries the treated material PM obtained at a high temperature in the contact treatment step S2 to room temperature (approximately 25°C). The cooling and drying device 36 includes a container 71 that accommodates the treated material PM obtained in the contact treatment step S2, a temperature controller 72 that measures and adjusts the internal temperature of the container 71, and a pressure reduction mechanism 73 that reduces the pressure inside the container 71. The container 71 accommodates the treated material PM and has an open-topped container body 71a and a lid 71b. The lid 71b has an opening 71c that is connected to the pressure reduction mechanism 73. The pressure reduction mechanism 73 includes a suction section (not shown) that sucks air from inside the container 71 and an inlet section (not shown) that stops suction and allows gas to flow into the container 71. The pressure reduction mechanism 73 reduces the pressure inside the container 71 by sucking air from inside the container 71 and also releases the reduced pressure inside the container 71 to restore normal pressure. The inlet section allows dry air (hereinafter referred to as dry air) or dry inert gas (hereinafter referred to as dry inert gas) to flow into the container 71, thereby returning the inside of the container 71 to normal pressure.

[0095] Once the treated feces and urine material 13 is placed in the container 71, it is cooled by cooling the inside of the container 71 using the temperature controller 72. During the cooling process, it is preferable to reduce the pressure inside the container 71 using the pressure reducing mechanism 73, more preferably to a level close to vacuum, in order to more reliably suppress condensation. After cooling, the suction by the pressure reducing mechanism 73 is stopped, and dry air or dry inert gas is introduced through the inlet port to return the pressure to normal. As a result, the treated feces and urine material 13 is obtained as a dried material whose temperature has been reduced to room temperature while more reliably suppressing condensation. The opening 71c may be formed in the container body 71a.

[0096] If external air is allowed to flow into the container 71 when returning the pressure from a reduced pressure state to normal pressure, the treated feces and urine 13 may become contaminated with microorganisms. However, in this example, such microbial contamination is prevented by allowing dry air or dry inert gas to flow into the container 71 instead of external air, as described above. If microbial contamination is not an issue, the treatment facility 31 does not necessarily need to be equipped with the cooling and drying device 36, and the treated feces and urine 13 may be allowed to cool naturally to room temperature.

[0097] Due to the reduced pressure and suction of the high-temperature steam at the center of each particle of the material PM, the temperature of the material PM drops rapidly and gradually approaches room temperature. This temperature behavior can be measured by a temperature sensor (not shown) placed in the container 71. In this example, the moisture is evaporated by such reduced pressure and suction, and the treated feces and urine material 13 with a moisture content of 20% or less is obtained.

[0098] The treatment facility 31 is equipped with the above-mentioned batch-type contact treatment device 35, but may also be equipped with a continuous contact treatment device instead of the contact treatment device 35. In Fig. 10, the continuous contact treatment device 85 is not particularly limited as long as it can bring superheated steam into contact with the granular mixture 22 (livestock manure 11 in the first embodiment, and manure mixture 17 in the second embodiment), which is the object to be treated. The contact treatment device 85 is a conveyor-type contact treatment device equipped with a transport section 86 that transports the granular mixture 22, and a contact treatment section 87 that brings superheated steam 23 (see Fig. 7) into contact with the object to be treated during transport.

[0099] The conveying unit 86 includes a long, annular belt-shaped conveying belt 90 on which the granular mixture 22 is placed, a hopper 91 that supplies the granular mixture 22 to the conveying belt 90 from above, and a plurality of rollers 92a-92i that support the conveying belt 90 and form a conveying path, at least one of the rollers 92a-92i being a drive roller having a motor 93. In FIG. 10, the upstream-most roller 92a and the downstream-most roller 92i in the conveying direction of the granular mixture 22 (hereinafter simply referred to as the conveying direction) are depicted as drive rollers. The conveying unit 86 further includes a drive controller 94 that rotates the drive roller in a circumferential direction by the motor 93, a collection container 96, and the like. By rotating the drive roller by the drive controller 94, the annular conveying belt 90 that contacts the circumferential surface of the drive roller travels in a circular motion. As a result, the granular mixture 22 placed on the conveyor belt 90 from the hopper 91 is conveyed and collected in a collection container 96 provided below one end of the travel path of the conveyor belt 90.

[0100] The conveyor belt 90 is a long, annular mesh member 58a (see FIG. 7). The contact treatment section 87 is provided to form a treatment space above the conveyor belt 90, in which the superheated steam 23 is brought into contact with the granular mixture 22. In this example, a pair of support members 61 in the contact treatment section 37 are provided in an upright position on both ends of the width direction of the conveyor belt 90 to form the treatment space. The support members 61 in this example are intended to separate the treatment space from the external space. The length L61 of the support members 61 in the conveying direction may be set appropriately depending on the length of the conveying path, the conveying speed, etc. Furthermore, a top plate may be provided above the pair of support members 61 to form a tunnel-like treatment space.

[0101] A pair of supply pipes 62 for supplying superheated steam 23 to the processing space are provided below the conveyor belt 90 and on both sides of the conveyor belt 90 in the width direction. As in the contact processing section 37, the supply pipe 62 below the support member 61 is arranged in an upwardly inclined position so that an outlet 62о (see FIG. 7) for discharging superheated steam 23 faces the underside of the conveyor belt 90 on which the granular mixture 22 is placed. As a result, the superheated steam 23 emitted from the outlet 62о passes through the mesh of the conveyor belt 90 and comes into contact with the granular mixture 22 on the conveyor belt 90. In this way, the processing space is formed on the conveyor belt. In this example, there is one supply pipe 62 in the conveying direction, but there may be two or more.

[0102] In this example, the temperature of the superheated steam 23, the amount of superheated steam 23 generated per hour, and the temperature at the discharge port 62о are fixed. However, the temperature at the outlet of the treatment space (the downstream end of the support member 61 in the conveying direction) varies depending on the moisture content of the granular mixture 22. The inlet temperature is preferably at least 160°C, i.e., 160°C or higher. From the viewpoint of the treatment efficiency of the granular mixture 22 containing organic rice husks 15, the inlet temperature is more preferably in the range of 160°C to 400°C, even more preferably in the range of 170°C to 400°C, and particularly preferably in the range of 180°C to 250°C. If the outlet temperature cannot be detected, a temperature sensor (not shown) may be installed on the top of the conveyor belt 90 or on the inner surface of the support member 61 in the width direction of the conveyor belt 90 to detect the temperature around the conveyor belt 90, and this detected temperature may be regarded as the outlet temperature. It is desirable to install temperature sensors both at the discharge port 62о and at the outlet.

[0103] The temperature of the superheated steam 23 and the amount of liquid water required to generate the superheated steam 23 are constant. Under these constant conditions, the outlet temperature varies depending on the moisture content of the granular mixture 22. Using the change in the outlet temperature as an indicator, the outlet temperature decreases after treatment begins and then eventually rises. Until this increase begins, decomposition of organic matter primarily occurs. From the time the outlet temperature begins to rise until it reaches the inlet temperature, the granular mixture 22 is dried and partially roasted (reducing roasting, in which the component siliceous shale is reduced). For organic matter decomposition, it is preferable to set the conveying speed of the conveyor belt 90, etc., taking into account the temperature of the outlet 62о, the contact treatment with the superheated steam 23 at a high moisture content, and the timing of removal depending on the change in the outlet temperature. With the above configuration, whether the material to be treated is livestock manure 11, a manure mixture 17, or a granular mixture 22 without any other substances added, livestock manure 11 can be efficiently and simply treated, and the resulting treated manure 13 is useful as a soil amendment composition. [Example]

[0104] [Example 1-1] to [Example 1-18] Using the livestock manure treatment method shown in Figure 1, Examples 1-1 to 18 were carried out, each with different types of livestock manure 11 and treatment conditions as shown in Table 4. All of the livestock manure 11 had a total nitrogen content of 2% or more on a dry matter basis, and a total nitrogen, phosphorus, and potassium content of 5% or more. The swine manure was collected from a pig farm in Hiroshima Prefecture that does not use bedding and separates feces and urine for treatment. The chicken manure was collected from an area below the cages of a chicken farm in Okayama Prefecture where there is no bedding.

[0105] The contact treatment step S2 was carried out using the continuous contact treatment device 85 described above. The drying treatment in the cooling and drying step S3 was carried out for 5 hours under heating set at 100°C. In Table 4, "Pre-drying" indicates whether the livestock manure 11 used for treatment was dried beforehand or not; in other words, if it was not dried, it is marked "No." The moisture content (unit: %) is a dry weight value. That is, when the mass of the livestock manure 11 used for treatment is Ma and the mass after drying for 5 hours in a constant temperature drying device set at 100°C (variation range: ±2°C) is Mb, the moisture content is calculated by {(Ma - Mb) / Mb} x 100.

[0106] The treated feces and urine 13 obtained using chicken manure as the livestock manure 11 had a moisture content in the range of 10% or more and 14% or less in all Examples, for example, the moisture content of the treated feces and urine 13 in Examples 1-5 was 12.3%. The treated feces and urine 13 obtained using swine manure as the livestock manure 11 had a moisture content in the range of 13% or more and 17% or less in all Examples, for example, the moisture content of the treated feces and urine 13 in Examples 1-15 was 15.3%.

[0107] The obtained treated feces and urine product 13 was evaluated for the degree of inhibition of the Maillard reaction, the amount of soluble components, and the rate of reduction of nitrogen. The results are shown in Table 4. (1) Degree of inhibition of the Maillard reaction As the Maillard reaction progresses with heating, the color turns dark brown, so the color of the treated feces and urine 13 was evaluated as the degree of inhibition of the Maillard reaction according to the following criteria: A to C are pass, and D is fail. A: The color was similar to that of livestock manure 11, and no blackish browning was observed. B: Compared to livestock manure 11, it was only slightly browned. C: It was browner than livestock manure 11, but within the acceptable range. D: It was clearly dark brown.

[0108] (2) Amount of soluble components 30 g of treated manure 13 was placed in a 500 ml container, and deionized water was slowly poured in without stirring to bring the total volume to 300 ml. The container was sealed and allowed to stand at 25°C for 96 hours. After standing, the liquid was separated into dispersed and precipitated components using filter paper (Advantec Toyo Co., Ltd., filter paper No. 1, capturing particles 6 μm or larger) used to separate soil particles from soil suspensions. The dissolved and insoluble components were then separated, and the mass of the dissolved component was measured. Specifically, after weighing the filter paper, the supernatant liquid was poured onto the filter paper. Deionized water was then added to the residue in the container and poured onto the filter paper. The filtrate was concentrated under reduced pressure at 40–45°C, transferred to a weighed container, and dried at 80°C. Next, after drying for 5 hours in a dryer set at 100°C (temperature fluctuation ±2°C), the container was weighed and the weight of the container was subtracted to determine the amount of soluble components, which was then evaluated according to the following criteria. The higher the soluble components, the more the treated manure 13 is decomposed and the smaller the particles it is made up of, which can be used more widely, for example, as liquid fertilizer. A to C are pass, and D is fail. In addition, for some examples, the amount of insoluble components was determined, and the results are also shown in Table 4. The amount of insoluble components was determined by drying the residue on the filter paper for 5 hours in a dryer set at 100°C (temperature fluctuation ±2°C), measuring the mass of the filter paper as is, and subtracting the mass of the filter paper, which was previously weighed, from this measurement result to determine the amount of insoluble components. A: Between 15g and 30g B: Between 10g and 15g C: Between 5g and 10g D: Less than 5g

[0109] (3) Nitrogen reduction rate Because the nitrogen reduction rate correlates with the dry matter reduction rate, which is the reduction rate of dry matter (solid content), the dry matter reduction rate was calculated as the nitrogen reduction rate. The dry matter reduction rate was calculated using the formula {(Sm1 - Sm2) / Sm1} × 100, where Sm1 is the dry matter mass of the livestock manure 11 to be treated and Sm2 is the dry matter mass of the resulting treated manure 13A. The dry matter mass S1 is calculated from the mass and moisture content of the livestock manure 11, and the dry matter mass S2 is calculated from the mass and moisture content of the treated manure 13A. In Table 4, the "Dry Matter Reduction Rate" column indicates the following: Note that the fertilizer components resulting from the composting and drying processes are expressed as a percentage of the dry matter. Because the total phosphorus and potassium are not lost, the dry matter equivalent percentage is higher than that of raw livestock manure due to the reduction in dry matter mass. A: Less than 5% B: Between 5% and 10% C: Between 10% and 15% D: 15% or more

[0110] [Table 4]

[0111] [Comparative Example 1-1] to [Comparative Example 1-2] The contact treatment step S2 of Examples 1-5 and 1-15 was replaced with a dry heat step, and livestock manure 11 was treated to obtain treated manure, resulting in Comparative Examples 1-1 and 1-2. In Table 4, "None" in the "Contact Treatment Step" column means that a dry heat step was carried out instead of the contact treatment step S2. The dry heat step is a step in which livestock manure 11 is heated without contact with superheated steam, i.e., without supplying superheated steam 23 to the livestock manure 11, and in Comparative Experiments 1-1 and 1-2, the livestock manure 11 was heated in a heating furnace set at a temperature of 200°C. The treatment time for the dry heat step is shown in the "Time" column of the "Contact Treatment Step".

[0112] The treated feces and urine obtained in Comparative Examples 1-1 and 1-2 were evaluated using the same methods and criteria as in Examples 1-5 and 1-15. The evaluation results are shown in Table 4. [Example]

[0113] Experiments 1 to 4 were conducted in which a manure mixture 17 was obtained from a chicken farm in Iwate Prefecture and treated with a treatment device 31 to obtain treated manure 13C. Experiment 4 was conducted as follows. Siliceous shale (diatomaceous earth) 19 was added to and mixed with the manure mixture 17 so that the mass of the siliceous shale 19 was 10% of the mass M22 of the granular mixture 22, i.e., 0.1 × M22. Excess moisture in the manure mixture 17 was retained in the siliceous shale 19. The siliceous shale mixture 21 was left to stand for 10 hours or more, since it takes 6 to 10 hours for the interface to no longer drop when the siliceous shale and twice the amount of water are placed in a measuring cylinder. Subsequently, water 24 was added using a mixing and granulating device 34 to obtain a granular mixture 22 with a moisture content of 45% (water-containing step S13), and a granulation step S1 was performed to obtain a granular mixture 22 with a particle size of 30 mm to 40 mm. Thereafter, in the contact treatment step S2 carried out using the contact treatment device 35, the temperature of the outlet 62о of the supply pipe 62 was detected, and this temperature was regarded as the temperature of the superheated steam 23 coming into contact with the granular mixture 22. This temperature and the time of the contact treatment step S2 are shown in the "Temperature" and "Time" columns of "Heat Treatment (Superheated Steam Treatment)" in "Experiment 4" in Table 5. In the cooling treatment in the cooling and drying step S3, the mixture was allowed to cool naturally while placed in the cooling and drying device 36, and the subsequent drying treatment was carried out by placing a desiccant in the cooling and drying device 36 and sealing it.

[0114] In addition, in Experiments 1 to 3, the same siliceous shale mixture 21 as that produced in Experiment 4 was used to obtain treated manure 13C without carrying out the hydration step S13. That is, in Experiments 1 to 3, water 24 was not supplied to the siliceous shale mixture 21, and the mixture was not hydrated. The temperature of the superheated steam 23 in the contact treatment step S2 was set to the temperature shown in Table 5. The other conditions were the same as in Experiment 4.

[0115] 1. Analysis of fertilizer components The treated manure 13C obtained in Experiment 4 was analyzed for loss of fertilizer components according to the Fertilizer Testing Method. The results are shown in the "Experiment 4" column of Table 6. Table 6 also shows the analysis data for the control manure mixture 17 in the "Control" column.

[0116] [Table 5]

[0117] [Table 6]

[0118] The high moisture content calculated from the dry heat loss (drying conditions: 100°C ± 2°C, 5 hours) in Experiment 4 is presumably due to the water-retaining capacity of the siliceous shale 19. The pH change is presumably due to oxidation during dry heat, resulting from the use of a pre-dried sample or a dry heat loss sample. Based on these results, a treatment method that does not significantly reduce the total amounts of nitrogen, phosphorus, and potassium compared to the pre-treatment (equivalent to the "control") is desirable for use as an organic fertilizer raw material for ordinary fertilizer. The official specifications for total nitrogen, phosphorus, and potassium are 2.5% or more, total phosphorus, 1.0% or more, and moisture content 20% or less, on a dry matter basis. Experiment 4 met these specifications. The 10% addition of siliceous shale 19 is not a generous amount relative to the official specifications for fertilizer component values; therefore, it is preferable to limit the addition of siliceous shale 19 to the minimum necessary. It is also preferable to limit the amount of rice husk 15 added to the amount used in this example. The official standard is the official standard for the ordinary fertilizer "processed household manure fertilizer."

[0119] It can be seen that treated manure 13C does not suffer from significant component loss, unlike compost obtained by fermenting livestock manure 11, incinerated livestock manure 11, or burned livestock manure 11. Based on this premise, the results of each evaluation described below were considered.

[0120] [Control area] For comparison with Example 1 and the comparative examples described below, a "control group" is also shown in Table 5, and the "control group" in other tables corresponds to this. The control group is fermented compost made by fermenting manure mixture 17. In Table 6 and subsequent tables, sample number 5 represents the data for the control group.

[0121] The following evaluations were carried out on samples taken from the treated manure 13C obtained in each of Experiments 1 to 4 and the fermented compost from the control plot.

[0122] 2. Degree of decomposition of rice husks Each sample was touched to evaluate the degree of rice husk decomposition based on the presence or absence of the tingly feeling of rice husk due to the plant opal structure, and the degree of the feeling. The evaluation results are shown in the "Palptical Evaluation of Decomposition" column in Table 7. Additionally, samples were observed using an optical microscope at 10x and 40x magnification, and those in which the silicic acid layer and cell outer membrane were confirmed under the microscope are shown in the "Exposed Silica Layer" and "Exfoliated Cell Outer Membrane" columns in Table 7. "X" indicates that no confirmation was made, and "Observed Area" indicates that confirmation was made through microscopic observation. Images of the samples observed under an optical microscope are shown in the figures (Figures 11A to 11J) indicated by the drawing numbers in the "Reference Drawings" section of Table 7. Note that "10x" and "40x" in Table 7 are the magnifications used for observation.

[0123] [Table 7]

[0124] Decomposition of rice husks 15 requires decomposition of β-1,4-glucan in the rice husk husks. To decompose rice husks 15 to the same degree as fermented chicken manure through contact treatment with superheated steam 23, it is preferable to increase the temperature at the supply port 620 in the superheated steam treatment and to increase the moisture content to ensure sufficient time for the contact treatment process (including adding water). As can be seen from Figures 11A to 11G, decomposition of rice husks 15 has progressed to the point where the silicic acid layer is exposed and the cell outer skin is peeled off only in the manure treatment product 13C.

[0125] 3. Volatile organic matter content The amount of volatile organic substances in each sample was measured as an indicator of the breakdown of organic matter into smaller molecules. A 200 ml container containing 20 g of sample and an air analyzer were placed in an 8 L (liter) dry box, with the lid of the 200 ml (milliliter) container left open. After 15 minutes, the monitored value shown in the air analysis was checked and used as the measured value. The air analyzer used was a Motobuy gas analyzer (JSM-131). The results are shown in Table 8.

[0126] [Table 8]

[0127] The main components of volatile organic matter are thought to be lower fatty acids. These are also cited as substances that cause bad odors, which is why odors were reduced in Experiment 2. Experiment 4 shows that decomposition of organic matter, including rice husks 15, which is similar to fermented compost, is progressing.

[0128] 4. Making nutrients available after fertilization The potential for nutrient supply to plants when each sample was mixed into soil was evaluated by measuring the availability of nutrients after fertilization. 20 g of sample was weighed into a 200 ml bottle with a lid, and 80 g of soil leachate was added before the bottle was sealed. Rhizosphere soil was collected during cultivation, and five times the volume of deionized water was added. The mixture was mixed, stirred, and allowed to stand. The supernatant liquid was used as the soil leachate. Electrical conductivity and pH (hydrogen ion index) were measured 1 hour, 24 hours, 48 ​​hours, and 72 hours after sealing. Electrical conductivity was measured using an EC monitor (Twin COND meter manufactured by AS ONE Corporation). pH was measured using a HORIBA portable pH / water quality system. The temperature inside the bottle was 28–29°C during measurements. The results are shown in Table 9.

[0129] [Table 9]

[0130] In both the control and Experiments 1-4, the EC values ​​reached after 72 hours were 14.3-16.3, which was comparable to the expected concentration of water-soluble fertilizer salts. The EC values ​​one hour after the start of treatment were higher for chemical fertilizers, which are fast-acting fertilizer components, and lower for organic fertilizers. The EC values ​​one hour after the start of treatment were approximately 36% of the EC values ​​after 72 hours in the control, while the comparative and inventive examples exhibited different behaviors, ranging from 60-67%. The control was consistent with previous findings, but the characteristics of the superheated steam-treated material suggest that it contains readily available fast-acting fertilizer components. The pH changes differed between the control and Experiments 1-4. The control was consistent with the results in Table 6, but Experiments 1-4 showed a weak acidity. In Table 6, the pH was measured on samples after dry-heat drying. This difference was due to the use of the fertilizer in its original form. It has been argued that contact treatment with superheated steam primarily involves reductive pyrolysis, and pH is considered to be one indirect measure supporting this. The product of contact treatment with superheated steam is characterized by its weakly acidic to neutral pH. It is known that nutrient absorption by plants is promoted in neutral to weakly acidic soils, and inhibited in neutral to weakly basic soils.

[0131] 5. Soil reduction test Using the same method as in "4. Making nutrients available after fertilization," the oxidation-reduction potential was measured with an ORP monitor 1 hour, 24 hours, 48 ​​hours, and 72 hours after plugging, and the results were displayed as standard hydrogen electrode values. The results are shown in Table 10.

[0132] [Table 10]

[0133] The potential of soil pore water changes due to the reduction reaction occurring in the soil. In this test, the potential of the solution area (assumed to be the flooded area in this field) falls below 0 mV. It has been reported that the growth of plant pathogenic microorganisms in the soil is completely inhibited. Furthermore, at -100 mV to -200 mV, not only the nitrogen fertilizer components that had been oxidized and fixed in the soil particles, but also phosphate, calcium, and silica are made available (reduced and available). The results in Table 10 suggest that soil reduction reactions behave in the same way. Therefore, it can be inferred that the effects on plant pathogens and the reductive availability of fertilizer components occur in the same way. The results after one hour in Table 9 are thought to be due to the characteristics of the superheated steam-treated material, rather than due to reductive availability.

[0134] 6. Effects on soil microorganisms The CO2 (carbon dioxide) content of the sample prepared in "3. Making components available after fertilization" was measured to evaluate its possible impact on soil microorganisms. Using the same method as in "2. Volatile organic matter content," a 200ml container containing 20g of sample and a CO2 monitor were placed in an 8L dry box, with the lid of the 200ml container left open. After 15 minutes, the CO2 monitor readings were observed and measured. Measurements were taken at 1 hour, 24 hours, 48 ​​hours, and 72 hours after the start of the experiment. The results are shown in Table 11.

[0135] [Table 11]

[0136] Soil microorganisms are essential for the mineralization of nitrogen components in chemical fertilizers, and organic fertilizers are also important as a source of nutrients for soil microorganisms. As the results show over the course of 72 hours, the respiration rate of soil microorganisms increased quadratically in Experiments 1 to 4. It is estimated that, unlike fermented chicken manure, superheated steam contact treatment does not inhibit the activity of soil microorganisms after application. [Explanation of symbols]

[0137] 11 Livestock manure 13A~13C Treated excrement 15 Rice husks 17 Manure mixture 19 Siliceous shale 21 Siliceous shale mixture 22 Granular mixture 23 Superheated steam 24 water 31 Processing facilities 33 Crushing equipment 34 Mixing granulation equipment 35,85 Contact treatment equipment 37,87 Contact treatment section 38 Superheated steam supply section S1 Granulation process S2 Contact treatment process

Claims

1. A method for treating livestock manure, characterized by contacting superheated steam with livestock manure containing a mixture of silicic acid-containing plant-based organic material and granular siliceous shale.

2. 2. The method for treating livestock manure according to claim 1, wherein the plant-based silicate organic material is rice husk.

3. a siliceous shale mixing step of mixing the manure mixture of the livestock manure and the siliceous plant-based organic material with granular siliceous shale to form a siliceous shale mixture; a hydration step of hydrating the siliceous shale mixture with liquid water; a contact treatment step of contacting the siliceous shale mixture containing water with the superheated steam; The method for treating livestock manure according to claim 1 or 2, comprising:

4. 4. The livestock manure treatment method according to claim 3, wherein the siliceous shale mixing step mixes the siliceous shale with the undried manure mixture.

5. The method further includes a granulation step of forming the siliceous shale mixture into granules, 5. The livestock manure treatment method according to claim 3, wherein the contact treatment step comprises bringing the superheated steam into contact with the siliceous shale mixture in a granular form containing the water.

6. The livestock manure treatment method according to claim 5, wherein the granulation step includes the water impregnation step.

7. 7. The livestock manure treatment method according to claim 1, wherein the temperature of the treatment space in which the superheated steam is brought into contact is within the range of 160°C or higher and 400°C or lower.

8. A method for producing a soil-modifying composition, characterized in that livestock manure containing a mixture of silicic acid-containing plant-based organic material and granular siliceous shale is brought into contact with superheated steam to produce a soil-modifying composition.

Images