Composition for adsorbing hydrogen sulfide having bauxite tailings and shells, method of manufacturing the same, and method of manufaturing livestock manure compost using the same

Abstract

The present invention relates to a composition for adsorbing hydrogen sulfide comprising bauxite residue and seashells, a method for manufacturing the same, and a method for manufacturing livestock manure compost using the same. The composition for adsorbing hydrogen sulfide comprises bauxite residue and seashells, enables the composting of livestock manure, and can stably adsorb and remove hydrogen sulfide.

Description

Technology Field

[0001] The present invention relates to a composition for adsorbing hydrogen sulfide comprising bauxite residue and seashells, and more specifically, to a composition for adsorbing hydrogen sulfide comprising bauxite residue and seashells, a method for manufacturing the same, and a method for manufacturing livestock manure compost using the same. Background Technology

[0002] Generally, if natural minerals and inorganic substances required by crops are insufficient, the deficit is supplied directly to the soil or crops using fertilizer. Furthermore, if even one of the nutrients necessary for crop growth is deficient, it significantly affects not only the growth of the crop but also its yield and quality.

[0003] Fertilizer is a substance containing nutrients to help the growth of crops, and is mainly spread on cultivated land and mixed with part of the topsoil where crops are planted. In addition, fertilizers generally contain one or more of the three major fertilizer elements, such as nitrogen, phosphorus, and potassium, which can help the growth of crops, and recently, fertilizers containing the aforementioned three major elements and various minerals are also being presented.

[0004] Furthermore, while chemically processed fertilizers were primarily used in the past for mass production, the use of chemical fertilizers is currently being minimized due to soil pollution and the preference for eco-friendly crops.

[0005] In addition, various methods for producing fertilizer using organic waste such as livestock manure and food waste have recently been proposed, and in particular, various methods for converting the aforementioned organic waste into fertilizer by removing moisture, odors, and harmful bacteria contained therein are being presented.

[0006] In particular, biogas produced from livestock manure is generated through the process of anaerobic digestion, that is, the process in which biodegradable organic matter is decomposed by microorganisms under anaerobic conditions.

[0007] This biogas mainly contains methane and carbon dioxide, and also includes small amounts of hydrogen sulfide, ammonia, and water.

[0008] Hydrogen sulfide contained in biogas is a strong acidic gas that must be removed, as it can cause corrosion of pipes and equipment when it reacts with water to produce sulfuric acid.

[0009] Bauxite tailings are the sludge remaining after extracting aluminum hydroxide from bauxite raw minerals by the Bayer method (a method of extracting aluminum hydroxide by adding sodium hydroxide (NaOH) to raw minerals containing a large amount of alumina).

[0010] Since these bauxite residues are generated during the process of using high concentrations of sodium hydroxide, they have a strong alkaline pH of 12 or higher and typically contain 20-25 wt% Al2O3, 15-20 wt% SiO2, 25-30 wt% Fe2O3, 2-5 wt% CaO, 10-15 wt% Na2O, and 5-10 wt% TiO2. As such, bauxite residues contain various forms of minerals and possess the property of having different types of charges at a given pH, which gives them the advantage of having excellent ability to immobilize and stabilize heavy metals.

[0011] Shellfish (which have a plate-like structure, while oyster shells have a plate-like structure) are mollusks that enclose their bodies with two flat shells. The shells surrounding shellfish are primarily composed of calcium and are used to produce lime by burning, as well as for decorative items, cosmetic materials, animal feed, and construction materials. Previously managed as waste shells—part of animal and plant residues—under the former Property Management Act, waste shells are now classified as fishery by-products under current law following the enforcement of the Act on the Promotion of Recycling of Fishery By-products on July 21, 2022. These waste shells are recycled in various fields; domestically, they are primarily recycled into eco-friendly fertilizers by granulating them into 2 x 1 / 2 mm particles through a rotating cylinder while spraying water. However, although waste shells are classified as industrial waste, the lack of proper disposal methods and institutional support not only imposes an economic burden on fishermen but also causes serious environmental damage due to odors and other issues. Therefore, not only shellfish producers and processors but also local governments such as Tongyeong and Yeosu urgently need measures to efficiently and rapidly recycle shells for sustainable aquaculture, processing, and distribution.

[0012] To address this, research was conducted to remove odors and hydrogen sulfide by utilizing iron oxide (Fe2O3), the main component of bauxite residue, and porous seashells, which have excellent sulfur oxide adsorption capabilities. Since bauxite residue is in a sludge state with a moisture content of approximately 30–45%, it is not easy to handle. In this process, a technology was developed to manufacture a hydrogen sulfide removal agent in pellet form by mixing seashell powder with bauxite residue. Prior art literature

[0013] Patent Document 1: Korean Registered Patent Publication No. 10-230870 Patent Document 2: Korean Registered Patent Publication No. 10-1905157 The problem to be solved

[0014] The objective of the present invention is to provide a composition for adsorbing hydrogen sulfide capable of removing hydrogen sulfide generated from livestock manure, etc., by utilizing bauxite residue and waste shells.

[0015] In addition, the invention aims to provide a method for manufacturing a composition for adsorbing hydrogen sulfide comprising bauxite residue and seashells, and a method for manufacturing livestock manure compost using the same. means of solving the problem

[0016] According to one embodiment of the present invention, a composition for adsorbing hydrogen sulfide comprising bauxite residue; and seashell is provided.

[0017] In the present invention, a composition for adsorbing hydrogen sulfide may be provided, comprising one or more shells selected from the group consisting of calcined shells and ordinary shells.

[0018] In the present invention, the bauxite residue may provide a composition for adsorbing hydrogen sulfide comprising 30 to 40 weight% iron oxide and 15 to 25 weight% aluminum oxide.

[0019] In the present invention, a composition for adsorbing hydrogen sulfide can be provided that further comprises a liquid amino acid.

[0020] In the present invention, a composition for adsorbing hydrogen sulfide can be provided, comprising 40 to 70 weight% of the bauxite residue; 20 to 50 weight% of the seashell; and 10 to 20 weight% of the liquid amino acid.

[0021] In the present invention, a composition for adsorbing hydrogen sulfide can be provided that further comprises quicklime.

[0022] In the present invention, a method for preparing a composition for adsorbing hydrogen sulfide can be provided, comprising the steps of: mixing bauxite residue; seashell; and liquid amino acid; and molding into a pellet-type solid.

[0023] In the present invention, the shell comprises a calcined shell, and the calcined shell is prepared by the following steps: washing the shell; calcining the washed shell by heat treatment at 600 to 800°C; and crushing and grinding the calcined shell into particles of 1 to 2 mm. A method for preparing a composition for adsorbing hydrogen sulfide can be provided.

[0024] In the present invention, a hydrogen sulfide removal agent comprising the above-mentioned composition for adsorbing hydrogen sulfide can be provided.

[0025] In the present invention, a method for manufacturing livestock manure compost that adsorbs hydrogen sulfide can be provided by mixing the hydrogen sulfide removal agent and livestock manure.

[0026] In the present invention, a method for manufacturing livestock manure compost can be provided, comprising the step of separating a hydrogen sulfide removal agent adsorbed with hydrogen sulfide and recovering the livestock manure. Effects of the invention

[0027] The composition for adsorbing hydrogen sulfide comprising bauxite residue and seashells according to the present invention, the method for manufacturing the same, and the method for manufacturing livestock manure compost using the same involve mixing seashell powder with bauxite residue to produce a hydrogen sulfide removal agent in pellet form, thereby enabling the composting of livestock manure and stably adsorbing and removing hydrogen sulfide. Brief explanation of the drawing

[0028] Figure 1 is a graph showing the hydrogen sulfide adsorption rate of bauxite residue and seashells according to the present invention. Figure 2 is a diagram illustrating the hydrogen sulfide adsorption rate experiment method of Figure 1. Figures 3 and 4 are graphs illustrating the adsorption rate according to the mixing ratio of bauxite residue and seashells and the presence or absence of liquid amino acid addition. Specific details for implementing the invention

[0029] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the present invention, and the present invention is defined only by the scope of the claims.

[0030] The terms used in this specification are for describing embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. The terms "comprises" and / or "comprising" used in this specification do not exclude the presence or addition of one or more other components in addition to the components mentioned. Throughout the specification, the same reference numerals refer to the same components, and "and / or" includes each of the mentioned components and all combinations of one or more. Although terms such as "first," "second," etc., are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish them from a single component. Therefore, the first component mentioned below may be the second component within the technical scope of the invention.

[0031] Unless otherwise defined, all terms used herein (including technical and scientific terms) may be used in a meaning commonly understood by those skilled in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise.

[0032] FIG. 1 is a graph showing the hydrogen sulfide adsorption rate of bauxite residue and seashells according to the present invention. FIG. 2 is a diagram explaining the experimental method for the hydrogen sulfide adsorption rate of FIG. 1. FIG. 3 and FIG. 4 are graphs explaining the adsorption rate according to the mixing ratio of bauxite residue and seashells and the presence or absence of liquid amino acid addition.

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0034] A composition for adsorbing hydrogen sulfide according to one embodiment of the present invention comprises bauxite residue and seashells.

[0035] Aluminum (Al) metal is a material with a global production of approximately 50 million tons as of 2013, but it does not occur naturally; it exists abundantly in the Earth's crust as oxides or silicon compounds. Consequently, to produce this aluminum, alumina (Al2O3), manufactured by calcining aluminum hydroxide (Al(OH)3) extracted from bauxite, is used as a raw material.

[0036] Globally, over 95% of aluminum hydroxide is manufactured using the Bayer process. This method involves heating bauxite, the raw material, with caustic soda under high temperature and high pressure conditions to produce a sodium aluminate solution that leaves an insoluble residue, which is then precipitated using the seed method. There are a total of approximately 110 manufacturing plants, with about 50 of them operating in China.

[0037] More than 90% of the alumina produced in the world is used to manufacture aluminum metal and is named metallurgical or smelting alumina (SGA), while the remainder is called non-metallic grade alumina (NMGA).

[0038] Aluminum hydroxide is used to produce water treatment chemicals (aluminum sulfate, polyaluminum chloride, and sodium aluminate), zeolites, and alumina, and alumina is utilized in a wide range of applications such as refractory products, ceramic materials, abrasives, catalysts, tiles, and glass.

[0039] The aluminum hydroxide manufacturing process using bauxite inevitably generates bauxite residue, amounting to approximately 120 million tons annually worldwide, and is one of the industrial byproducts that poses a problem in modern society.

[0040] The composition of bauxite residue consists of iron oxide, titanium oxide, silicon oxide, and insoluble alumina, and includes various oxides depending on the origin of the bauxite. The highly concentrated iron oxide in bauxite gives the byproduct a distinctive red color and is generally called 'Red Mud'.

[0041] Iron oxide (Fe2O3), the main component of bauxite residue, has excellent odor removal efficacy.

[0042] Shellfish are mollusks whose bodies are encased in two flat shells. The shells surrounding shellfish are primarily composed of calcium and are used to produce lime by burning, as well as for decorative items, cosmetic materials, animal feed, and construction materials. Previously managed as waste shells—part of animal and plant residues—under the former Property Management Act, waste shells are now classified as fishery by-products under current law following the enforcement of the Act on the Promotion of Recycling of Fishery By-products on July 21, 2022. Although waste shells were previously classified as industrial waste, the lack of proper disposal methods and insufficient institutional support not only imposes an economic burden on fishermen but also causes serious environmental damage due to odors and other issues.

[0043] These seashells are porous and possess excellent efficacy in adsorbing sulfur oxides. Furthermore, the bauxite residue is difficult to handle due to its very high moisture content; however, by mixing it with seashell powder, the bauxite residue can be solidified, and thus, the seashells serve as a solidifying agent.

[0044] By preparing a composition for adsorbing hydrogen sulfide using the above bauxite residue and the above seashells, not only can the odor and hydrogen sulfide of livestock manure be easily removed, but environmental pollution problems can also be resolved by utilizing bauxite residue and waste seashells, which are industrial byproducts.

[0045] For example, the above shell may include one or more selected from the group consisting of calcined shells and ordinary shells.

[0046] Ordinary seashells are composed of calcium carbonate (CaCO3), but when calcined, they turn into quicklime (CaO), and quicklime has a hydrogen sulfide adsorption rate that is more than three times better than that of calcium carbonate.

[0047] For example, the bauxite residue may contain 30 to 40 weight percent iron oxide; and 15 to 25 weight percent aluminum oxide.

[0048] The above composition for adsorbing hydrogen sulfide may further include liquid amino acids.

[0049] The above-mentioned liquid amino acid was used by water-solubleizing solid gelatin raw material to convert it into a liquid amino acid. The above-mentioned liquid amino acid also adsorbs hydrogen sulfide and has the effect of increasing the hydrogen sulfide adsorption rate when used together with the above-mentioned bauxite residue and the above-mentioned seashell.

[0050] The above liquid amino acid not only adsorbs hydrogen sulfide, but also acts as a neutralizing agent to neutralize the bossite residue, which has a very high pH of 10 or higher.

[0051] In one embodiment of the present invention, the composition for adsorbing hydrogen sulfide comprises 40 to 70 weight% of the bauxite residue, 20 to 50 weight% of the seashell, and 10 to 20 weight% of the liquid amino acid.

[0052] Based on the total weight of the above hydrogen sulfide adsorption composition, the bauxite residue is included in an amount of 40 to 70 weight%, and if it falls outside this range, the odor removal ability is significantly reduced, and the seashell is included in an amount of 20 to 50 weight%, and if it falls outside this range, the hydrogen sulfide adsorption rate is significantly reduced. In addition, the liquid amino acid is included in an amount of 10 to 20 weight%, and if it falls outside this range, there is a problem that the adsorption rate is significantly reduced.

[0053] For example, it is preferable that the bauxite residue and the shells be mixed in a weight ratio of 5:5 to 7:3, and more preferably, that the bauxite residue and the shells be mixed in a weight ratio of 5:5.

[0054] For example, if necessary, the above composition for adsorbing hydrogen sulfide may further include quicklime.

[0055] Such hydrogen sulfide adsorption compositions are relatively easy to manufacture and can be produced at low cost; furthermore, compost made from livestock manure from which hydrogen sulfide has been removed is high in calcium and minerals, which are absent in conventional organic livestock manure compost, and has a soil improvement effect.

[0056] A method for preparing a composition for adsorbing hydrogen sulfide according to one embodiment of the present invention comprises the steps of mixing bauxite residue, seashells, and liquid amino acids, and molding into a pellet-type solid.

[0057] The step of forming the above pellet-type solid form is a step of feeding bauxite residue, crushed and shredded seashell powder and liquid amino acid into a pellet molding machine and then rotating the molding machine to produce a pellet-type hydrogen sulfide adsorption molded product, and may further include a step of drying the above pellet-type molded product at room temperature (15 to 25°C) to produce a solid form, but is not limited thereto.

[0058] Any molding machine may be used as long as the purpose is to form a pellet-shaped material by rotating the above-mentioned pellet molding machine with the molded material placed inside to ensure uniform mixing of the raw materials, and to smoothly polish the outer surface of the molded material through frictional contact with the inner surface of the molding machine and to harden it.

[0059] In the present invention, the step of molding into the pellet-type solid may be characterized by being manufactured into a pellet-type solid having a moisture content of 1 to 3 weight%, 1 to 2.5 weight%, or 1 to 2 weight%, and suitably, being manufactured into a pellet-type solid having a moisture content of 1 to 1.5 weight%. For example, if the moisture content is less than 1 weight%, a problem may occur where molding does not occur well during the pelletizing process, and if the moisture content exceeds 3 weight%, a problem may occur where a large amount of energy is consumed during drying. In addition, the pellet may have a size of 1 to 10 mm, 2 to 9 mm, or 3 to 8 mm.

[0060] For example, the above shell includes a calcined shell, and the calcined shell can be manufactured by going through the steps of washing the shell, heat-treating the washed shell at 600 to 800°C to calcine it, and crushing and grinding the calcined shell into particles of 1 to 2 mm.

[0061] In the present invention, the term "shell" refers to a commonly used shellfish shell and may include one or more shells selected from the group consisting of, for example, scallops, mussels, clams, Manila clams, oysters, short-necked clams, and razor clams; suitably, oyster shells or shellfish shells may be used, but are not limited thereto.

[0062] The above oyster shell may consist of 93 to 97 weight percent calcium carbonate and 3 to 7 weight percent organic matter.

[0063] The step of washing the shell of the present invention may be characterized by washing with an organic matter decomposition material mixed in to remove the organic matter.

[0064] In the present invention, the step of washing the shell can be carried out by a conventional method using a mixture of water and an organic matter decomposition material, and 30 to 40 weight percent of organic matter and salt contained in the shell can be removed.

[0065] The above organic matter decomposition material may be an organic matter decomposition material produced by microorganisms, and may be selected from organic microbial groups such as photosynthetic bacteria, lactic acid bacteria, and yeast, for example; may use a material obtained by fermenting and aging grain powder using soil bacteria groups including photosynthetic bacteria, cultures of livestock intestinal bacteria, and rock powder, etc. Suitablely, may use an organic matter decomposition material including Bacillus or Saccharomyces, but is not limited thereto.

[0066] In the present invention, the washed shell can be heat-treated and calcined at a temperature of 600 to 800°C, 630 to 800°C, or 650 to 790°C. Suitablely, it can be heat-treated and calcined at a temperature of 660 to 780°C to remove organic matter remaining in the washed shell while increasing the alkali content of the shell, but is not limited thereto. For example, if heat-treated and calcined at a temperature below 600°C, a problem may arise where the organic matter of the shell increases, and if heat-treated and calcined at a temperature exceeding 800°C, a problem may arise where the production cost during calcination increases or the amount of carbon dioxide generated increases.

[0067] In addition, the step (S2) of heat-treating and calcining the washed shells may be calcined for 10 to 30 minutes, 15 to 25 minutes, or 17 to 23 minutes in order to recycle more than 80% of the waste shells into quicklime (CaO), but is not limited thereto. For example, if the calcination time is less than 10 minutes, the calcium (ca) content of the quicklime (CaO) is less than 80%, which may cause problems that make it difficult to recycle and use, and if the calcination time exceeds 30 minutes, the amount of carbon dioxide emitted during the calcination process may increase.

[0068] In the present invention, the calcined shell may include a step of crushing and breaking into particles of 1 to 2 mm, 1.4 to 1.9 mm, or 1.6 to 1.8 mm.

[0069] The hydrogen sulfide adsorption composition prepared in this way can be utilized as a hydrogen sulfide removal agent.

[0070] By mixing the hydrogen sulfide removal agent manufactured in this way with livestock manure, hydrogen sulfide generated from the livestock manure can be effectively adsorbed. By separating the livestock manure and the hydrogen sulfide removal agent in the form of pellets adsorbing hydrogen sulfide, the livestock manure can be recovered and processed to produce livestock manure compost utilizing it.

[0072] The present invention will be explained in more detail below through examples and comparative examples. However, these examples do not limit the scope of the present invention.

[0074] Examples 1 to 3

[0075] Bauxite residue (Example 1), calcined shell powder (Example 2), and general shell powder (Example 3) were packed into a column, hydrogen sulfide was injected, and the amount of adsorbed was measured by comparing the weight before and after injection. Here, the calcined shell powder was prepared by heat-treating washed shells at 800°C for 20 minutes to calcin them, and then crushing and grinding them into 1.7 mm particles, while the general shell powder was prepared by crushing and grinding them into 1.7 mm particles without heat treatment.

[0076] The experimental equipment was set up as shown in Figure 2, and a MultiRAE analyzer was used. Hydrogen sulfide gas was injected under the conditions of Table 1 below.

[0077] Infusion concentration (mg / L) Infusion flow rate (ml.min.) Weight (g) H2S N2 Example 1 93.4 3.4 500 3.00 Example 2 91.5 3.4 500 2.98 Example 3 94.4 3.4 500 2.95

[0078] Accordingly, the adsorption capacity of the compositions according to Examples 1 to 3 measured is as shown in Table 2 below.

[0079] Adsorption capacity (ug / g) Example 1 0.239 Example 2 0.046 Example 3 0.014

[0080] Referring to Figure 1 and Table 2, it was confirmed that the adsorption capacity of the bauxite residue itself is superior compared to other examples, and that Example 2, which uses calcined seashell powder, has an adsorption capacity about three times higher than Example 3, which uses ordinary seashell powder.

[0082] Examples 4 to 7

[0083] Examples 4 to 7 used a mixture of bauxite residue and calcined shell powder as shown in Table 3 below, mixed in the following weight ratios, and in particular, Examples 5 and 7 additionally included 20 parts by weight of liquid amino acid relative to the total weight of the bauxite residue and calcined shell powder.

[0084] Bauxite residue: weight ratio of calcined shell powder Liquid amino acids (parts by weight) Example 4 5:5 - Example 5 5:5 20 Example 6 7:3 - Example 7 7:3 20

[0085] Accordingly, the adsorption capacities of the compositions according to Examples 4 to 7 measured are as shown in Table 4 below. The adsorption capacities in Table 4 below represent the weight ratio of adsorbed hydrogen sulfide to the weight of the examples.

[0086] Adsorption capacity (mg / g) Example 4 0.020 Example 5 0.616 Example 6 0.111 Example 7 0.469

[0087] Referring to Table 4 and Figures 3 and 4 above, the adsorption capacities of Examples 4 and 6, in which bauxite and calcined shell powder were mixed in a specific weight ratio, were 0.020 mg / g and 0.111 mg / g, respectively, and it was found that Example 6, in which bauxite and calcined shell powder were mixed in a weight ratio of 7:3, had superior adsorption capacities compared to Example 4, in which they were mixed in a weight ratio of 5:5.

[0088] In contrast, in the case of Examples 5 and 7, in which liquid amino acids were additionally mixed, the adsorption capacity was 0.616 mg / g and 0.469 mg / g, respectively, indicating that Example 5, in which bauxite and calcined seashell powder were mixed in a weight ratio of 5:5, had superior adsorption capacity compared to Example 7, in which they were mixed in a weight ratio of 7:3.

[0089] That is, it was found that the hydrogen sulfide adsorption composition mixed with bossite residue and calcined shell powder had superior adsorption capacity compared to bossite residue and calcined shell powder respectively, and that the hydrogen sulfide adsorption compositions of Examples 5 and 7 mixed with liquid amino acids had much superior hydrogen sulfide adsorption capacity compared to Examples 4 and 6 without liquid amino acids.

[0090] Specific parts of the present invention have been described in detail above. It is evident to those skilled in the art that such specific descriptions are merely preferred embodiments and do not limit the scope of the invention. Accordingly, the actual scope of the invention is defined by the appended claims and their equivalents.

Claims

Claim 1 A composition for adsorbing hydrogen sulfide comprising 40-70% by weight of bauxite residue; 20-50% by weight of seashell; and 10-20% by weight of liquid amino acid. Claim 2 A composition for adsorbing hydrogen sulfide according to claim 1, wherein the shell comprises one or more selected from the group consisting of calcined shells and ordinary shells. Claim 3 A composition for adsorbing hydrogen sulfide according to claim 1, wherein the bauxite residue comprises 30 to 40 weight% iron oxide; and 15 to 25 weight% aluminum oxide. Claim 4 delete Claim 5 delete Claim 6 A composition for adsorbing hydrogen sulfide according to claim 1, further comprising quicklime. Claim 7 A method for preparing a composition for adsorbing hydrogen sulfide, comprising the steps of: mixing 40-70% by weight of bauxite residue; 20-50% by weight of seashell; and 10-20% by weight of liquid amino acid; and molding into a pellet-type solid. Claim 8 A method for manufacturing a composition for adsorbing hydrogen sulfide according to claim 7, wherein the shell comprises a calcined shell, and the calcined shell is manufactured by the following steps: washing the shell; calcining the washed shell by heat treatment at 600 to 800°C; and crushing and grinding the calcined shell into particles of 1 to 2 mm. Claim 9 A hydrogen sulfide removal agent comprising a composition for adsorbing hydrogen sulfide according to any one of claims 1 to 3 and 6. Claim 10 A method for manufacturing livestock manure compost that adsorbs hydrogen sulfide by mixing the hydrogen sulfide removal agent of claim 9 with livestock manure. Claim 11 A method for manufacturing livestock manure compost according to claim 10, comprising the step of separating a hydrogen sulfide removal agent adsorbed with hydrogen sulfide and recovering the livestock manure.

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