Fertilizer making use of slurry organic waste including water-soluble organic acid, water-soluble nitrogen, or water-soluble phosphoric acid, and manufacturing method thereof

Abstract

To provide a solid fertilizer useful for plants while preventing decay of highly hydrous slurry organic waste that is extremely easy to decay.SOLUTION: A fertilizer is obtained by adding at least one kind of sulfate selected from a group consisting of magnesium sulfate, manganese sulfate, iron sulfate, copper sulfate, zinc sulfate, and ammonium sulfate to slurry organic waste containing at least one kind selected from a group consisting of water-soluble organic acid, water-soluble nitrogen, and water-soluble phosphoric acid, and then adding hemihydrate gypsum to solidify the mix.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a fertilizer utilizing slurry-like organic waste that is high in moisture and easily putrefies, and a method for producing the same. [Background technology]

[0002] Organic waste discharged from food factories and livestock barns is generally highly nutritious, containing plenty of sugar, organic acids, nitrogen such as proteins and amino acids, phosphorus, potassium and minerals. For this reason, in small factories and livestock farms, nearby farmers take some of it and spread it directly on fields as fertilizer or use it as a fermentation aid for compost. However, because it is highly perishable, most of it is not used and is quickly disposed of as industrial waste.

[0003] When disposing of these organic wastes as industrial waste, they are generally in the form of a highly viscous suspension called a paste-like or porridge-like slurry that contains over 80% water, and because of their high BOD (biochemical oxygen demand) and SS (suspended solids) values, it is difficult to dispose of them directly into the environment. Therefore, after solid-liquid separation, the liquid fraction required biological treatment using activated sludge and fermentation, while the solid components required combustion treatment.

[0004] On the other hand, in light of the recent trend towards the depletion of fertilizer raw materials, rising prices, and the need to save energy, there is a growing push to make active use of these organic wastes as fertilizer resources, and attempts have been made to use the solid fraction obtained through solid-liquid separation as sludge fertilizer or compost by mixing it with other materials and fermenting and maturing it. However, in the case of slurry-like organic waste, it is difficult to add large amounts when mixing it with other materials, given the water content, and even now there is no method in which such waste can be used directly.

[0005] In other words, there is a social need for a technology that can rapidly convert highly perishable, highly water-containing slurry-like organic waste into a less perishable fertilizer.

[0006] In response to this demand, for example, there is a method in which quicklime is added to the fermentation waste liquid and the moisture is removed by the water absorption reaction and reaction heat (Patent Document 1). However, this method has problems in that a considerable amount of heat is generated during production and the mixing operation is dangerous.

[0007] In addition, focusing on the fact that gypsum hemihydrate solidifies through hydration, a technology has been disclosed in which gypsum hemihydrate is added to digestive fluid resulting from the fermentation of liquids separated from organic matter, such as water-containing manure, by a method such as a solid-liquid separation means, to solidify and turn the mixture into fertilizer (Patent Document 2).

[0008] This also has the problem that production costs are increased because processes such as solid-liquid separation are required to obtain digestive fluid from manure and other materials that contain moisture.

[0009] Therefore, the inventors tried to add gypsum hemihydrate to organic waste that contained a large amount of water and was in a slurry state to solidify it, but when the organic waste contained a large amount of water-soluble organic acid, water-soluble nitrogen, or water-soluble phosphoric acid, these strongly inhibited the solidification, and the solidification time of the gypsum hemihydrate could be significantly extended. Normally, food-derived waste begins to decay if left at room temperature for more than one day after being discharged, so if it takes a long time to solidify, bacteria, mold, and bad odors will occur, making it impossible to turn it into fertilizer.

[0010] Patent Document 3 also shows that even if one attempts to solidify water-soluble phosphoric acid or water-soluble nitrogen, such as ammonium phosphate (diammonium hydrogen phosphate) or ammonium nitrate (ammonium nitrate), with gypsum hemihydrate, these act as strong hardening retarders, so that hardening takes an extremely long time or the fertilizer cannot be solidified at all. In response to this, ammonium phosphate and ammonium nitrate are mixed with clay in advance and pelletized to prevent contact with gypsum hemihydrate, thereby realizing the creation of a solid fertilizer. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 50-121061 [Patent Document 2] JP 2006-263487 A [Patent Document 3] Special Publication No. 6-104596 Summary of the Invention [Problem to be solved by the invention]

[0012] However, the solid fertilizer of Patent Document 3 is used for cultivating seaweed by immersing it in seawater, and since the fertilizer components are difficult to dissolve from the pellets formed of clay in soil, it is not suitable for application to soil. In addition, a pelleting process must be added before mixing with hemihydrate gypsum, which increases the production cost. Furthermore, the inclusion of clay components reduces the fertilizer content, resulting in a problem of reduced fertilizing effect.

[0013] Therefore, an object of the present invention is to provide a method for converting highly perishable, highly water-containing slurry-like organic waste into a solid fertilizer that can be applied to farm fields or the like and is useful for the growth of plants, while preventing the waste from decaying. [Means for solving the problem]

[0014] As a result of intensive research into solving the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by adding at least one of magnesium sulfate, manganese sulfate, iron sulfate, copper sulfate, zinc sulfate, and ammonium sulfate to a slurry-like organic waste containing at least one of water-soluble organic acid, water-soluble nitrogen, and water-soluble phosphoric acid, and further adding gypsum hemihydrate to solidify the waste, thereby completing the present invention.

[0015] That is, the present invention provides a fertilizer obtained by adding at least one or more sulfates selected from the group consisting of magnesium sulfate, manganese sulfate, iron sulfate, copper sulfate, zinc sulfate, and ammonium sulfate to a slurry-like organic waste containing at least one or more sulfates selected from the group consisting of water-soluble organic acids, water-soluble nitrogen, and water-soluble phosphoric acid, and then adding gypsum hemihydrate to solidify the mixture.

[0016] The present invention also relates to the above fertilizer, in which 50 parts by mass or more and less than 500 parts by mass of hemihydrate gypsum is added to 100 parts by mass of a slurry-like organic waste containing at least one or more kinds selected from the group consisting of water-soluble organic acids, water-soluble nitrogen, and water-soluble phosphoric acid.

[0017] The present invention also relates to the above fertilizer, in which sulfate is added so that the total mass content of sulfate ions in the sulfate is 0.1 to less than 50 times the total mass content of water-soluble organic acid, water-soluble nitrogen, and water-soluble phosphate contained in the slurry organic waste.

[0018] The present invention also relates to the above fertilizer, wherein the slurry organic waste containing at least one or more selected from the group consisting of water-soluble organic acids, water-soluble nitrogen, and water-soluble phosphoric acid is a fermentation and stillage of distilled liquor.

[0019] The present invention also relates to a method for producing a fertilizer, which includes a step of adding one or more sulfates selected from the group consisting of magnesium sulfate, manganese sulfate, iron sulfate, copper sulfate, zinc sulfate, and ammonium sulfate to a slurry-like organic waste containing one or more sulfates selected from the group consisting of water-soluble organic acids, water-soluble nitrogen, and water-soluble phosphoric acid, and then adding gypsum hemihydrate to solidify the mixture. Effect of the Invention

[0020] According to the present invention, highly moisture-containing slurry-like organic waste, which is highly susceptible to decay, can be converted into a solid fertilizer containing nutrients such as organic acids, nitrogen or phosphorus, and minerals such as calcium, magnesium, iron, copper, zinc or manganese, which are useful for plant growth, while preventing the waste from decaying. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The organic waste used in the present invention is not particularly limited as long as it is a slurry containing water-soluble organic acid, water-soluble nitrogen or water-soluble phosphoric acid, and examples thereof include manure mixed wastewater discharged from piggery or cow shed, food processing residues generated in the manufacturing process of fermented foods such as umami seasonings such as amino acids, soy sauce, and vinegar, and fermentation distillation residues (distillation lees) obtained in the manufacturing process of distilled alcohol such as shochu and awamori. Among these, it is preferable to use food processing residues and fermentation distillation residues in which various components have already been decomposed by heat treatment following microbial treatment and are contained in an effective state that is easily usable by plants, and fermentation distillation residues are more preferable because they do not contain salts and are more suitable as plant fertilizer. The water content of the slurry organic waste is not particularly limited, but is preferably about 60 to 99% by mass, and more preferably about 80 to 99% by mass.

[0022] The contents of water-soluble organic acid, water-soluble nitrogen, and water-soluble phosphoric acid in the organic waste are not particularly limited, but for example, the content of water-soluble organic acid is preferably 0.0001 to 5 mass%, more preferably 0.001 to 3 mass%. The content of water-soluble nitrogen is preferably 0.0001 to 10 mass%, more preferably 0.001 to 3 mass%. The content of water-soluble phosphoric acid is preferably 0.0001 to 10 mass%, more preferably 0.001 to 3 mass%. The total content of water-soluble organic acid, water-soluble nitrogen, and water-soluble phosphoric acid in the organic waste is preferably 0.0005 to 30 mass%, more preferably 0.005 to 10 mass%. These contents can be measured by the measurement method described in the Examples.

[0023] In producing the fertilizer of the present invention, sulfate is added to the above-mentioned slurry-like organic waste. Examples of sulfate include magnesium sulfate, manganese sulfate, iron sulfate, copper sulfate, zinc sulfate, ammonium sulfate, etc., and one or more of these can be used, and either anhydrous or hydrated products can be used. Magnesium, iron, zinc, copper, manganese, and ammoniacal nitrogen are all essential components for plant growth, and iron, zinc, copper, manganese, etc. have a growth-promoting effect even in small amounts, and these minerals can be supplied by sulfate.

[0024] The amount of sulfate to be added to the slurry organic waste is not particularly limited, but for example, if the total mass content of water-soluble organic acid, water-soluble nitrogen, and water-soluble phosphoric acid contained in the slurry organic waste is 1, the total mass content of sulfate ions in the sulfate is preferably 0.1 times or more and less than 50 times that of the total mass content. The lower limit is more preferably 0.2 times or more, more preferably 0.5 times or more, even more preferably 1 time or more, and particularly preferably 2 times or more. On the other hand, the upper limit is more preferably less than 30 times. If the amount is lower than this range, for example, it may take more than 24 hours to solidify, and a process such as drying may be required. On the other hand, if the amount is high, it may not be completely dissolved in the water in the slurry organic waste, and the hemihydrate gypsum may not be hydrated uniformly, resulting in uneven solidification and making it difficult to handle.

[0025] The hemihydrate gypsum used in the present invention is solidified as a dihydrate by adding water, like anhydrous gypsum or hemihydrate gypsum. As the hemihydrate gypsum, dehydrated gypsum obtained by heating recycled dihydrate gypsum regenerated from dihydrate gypsum or gypsum board at 120°C to 160°C and dehydrating it can also be used. The hemihydrate gypsum is added to the slurry-like organic waste to which the sulfate has been added, thereby solidifying the waste.

[0026] Hemihydrate gypsum is a component that contains calcium sulfate as a main component and is used to rapidly solidify the above-mentioned slurry-like organic waste, but is also an important element for supplying calcium, which is essential for plant growth. Generally, slaked lime is often used to supply calcium to plants, but since slaked lime is alkaline, if applied in large amounts, the soil pH becomes too high, which can have a negative effect on plant cultivation. On the other hand, calcium sulfate is almost neutral, so it can supply calcium to plants without affecting the soil pH very much. In addition, by solidifying, it is possible to suppress the runoff of water-soluble components and to gradually release them by irrigation, which contributes to the sustainability of the fertilizer effect. In the present invention, it is presumed that the sulfate ions that constitute the above-mentioned sulfate act as common ions of gypsum and promote the crystallization of gypsum, so that even if a component that inhibits solidification is contained, it will be quickly converted into a solid fertilizer.

[0027] The mixing ratio of the slurry-like organic waste and the hemihydrate gypsum of the present invention is not particularly limited, but is preferably 50 parts by mass or more and less than 500 parts by mass of the hemihydrate gypsum per 100 parts by mass of the water content of the slurry, and more preferably 100 parts by mass or more and less than 300 parts by mass. If it is lower than this range, it may take, for example, 24 hours or more to solidify, and a process such as drying may be required to prevent decay. On the other hand, if it is higher than this range, the hemihydrate gypsum may not be hydrated uniformly, and solidification may become uneven, making it difficult to handle. After the slurry-like organic waste and the hemihydrate gypsum are uniformly mixed, the solidification proceeds by leaving it at about 20 to 25 ° C.

[0028] In addition to the above-mentioned components, the fertilizer of the present invention can contain organic acids such as citric acid, lactic acid, and acetic acid, rice bran and oil cake which are useful for plant growth, compost, organic fertilizer, phosphorus fertilizer, nitrogen fertilizer, potassium fertilizer, boron fertilizer, silica fertilizer, molybdenum fertilizer, and the like, within limits that do not impair the effects of the present invention.

[0029] In addition, various chelating agents may be added to increase the absorption efficiency of calcium, magnesium, iron, zinc, copper, manganese, etc., in plants. In this case, biodegradable citric acid and its salts, gluconic acid and its salts, amino acid chelates such as MGDA (dicarboxymethylalanine), GLDA (glutamic acid diacetate), and succinic acid chelates such as HIDS are more effective than non-biodegradable aminocarboxylic acid chelates such as EDTA (ethylenediaminetetraacetic acid), NTA (nitrilotriacetic acid), DTPA (diethylenetriaminepentaacetic acid), and HEDTA (hydroxyethylenediaminetriacetic acid), and organophosphorus chelates such as HEDP (etidronic acid), NTMP (nitrilotris(methylenephosphonic acid), and PBTC (2-phosphonobutane-1,2,4-tricarboxylic acid). (tetrasodium 3-hydroxy-2,2'-iminodisuccinate), and EDDS (ethylenediamine-N,N'-disuccinic acid) are more preferable. Of these optional additives, organic acids, phosphorus fertilizers, and nitrogen fertilizers can be formulated by mixing with the pulverized material after solidifying the slurry organic waste. Other additives can be added before or after solidification, but it is preferable to add chelating agents together with the sulfate salts to the slurry organic waste and then solidify it.

[0030] Furthermore, the fertilizer of the present invention can be used in combination with agricultural materials other than fertilizers, such as soil conditioners, agricultural chemicals such as insecticides and fungicides, and plant growth regulators such as hormone agents.

[0031] The fertilizer of the present invention obtained by solidification as described above can be used as a powder by pulverizing the pulverized material, or the pulverized material can be compressed and molded into granules or pellets using a mulmerizer, disc pelletizer, briquette machine, tablet molding machine, extruder, or other commonly used pressure molding device.

[0032] The processed solidified material can be spread on the soil in an appropriate amount before cultivating plants and mixed in with a tilling tool, etc. It can also be spread around the base of plants at the necessary time during cultivation. EXAMPLES

[0033] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0034] Examples 1 to 9, Comparative Examples 1 to 3 Preparation and solidification test of slurry organic waste solid fertilizer: Gypsum and metal sulfates were added to slurry-like organic waste and the solidification performance was evaluated. (1) Preparation of slurry-like organic waste and its components The awamori distillation residue was used, manufactured by Zuisen Shuzo Co., Ltd. The average values ​​of the components are shown in Table 1. The measurement methods for each component are shown below.

[0035] [Table 1]

[0036] (Method of measuring ingredients) Each component was measured according to the food and fertilizer analysis methods. <Moisture> The awamori distillation residue (hereinafter referred to as the sample) was dried in a 105°C air-blowing dryer, and the moisture content was calculated by subtracting the weight after drying from the weight before drying. <ph> Measurements were made using a compact pH meter LAQUA Twin (HORIBA). <Citric acid> The sample was filtered through a 0.45 μm filter and the solution was measured using an ion chromatograph DX-120 (Dionex) and an IonPac ICE-AS1 (Dionex) separation column with 2.0 mM octanesulfonic acid solution as the eluent at a flow rate of 0.5 ml / min. <Water-soluble nitrogen> The measurement was performed using the Devarda's alloy-Kjeldahl method. That is, the sample was filtered through a 0.45μm filter, hydrochloric acid (diluted with the same volume of water) and tin(II) chloride dihydrate were added to the analysis sample, Devarda's alloy was added, and the nitrate nitrogen was reduced. Then, sulfuric acid (diluted with the same volume of water) was added and pretreated by the Kjeldahl method to convert the total amount of nitrogen into ammonium ions. Sodium hydroxide solution was then added to the solution and steam distilled, and the separated ammonia was collected with 0.25mol / L sulfuric acid, and the excess sulfuric acid was neutralized and titrated with 0.1mol / L to 0.2mol / L sodium hydroxide solution to measure. <Water-soluble phosphoric acid> The measurement was performed using the ammonium vanadomolybdate method. That is, the liquid was prepared by filtering the sample through a 0.45 μm filter, and sulfuric acid, potassium sulfate, and copper (II) sulfate pentahydrate were added thereto and decomposed by heating to convert the total phosphorus into phosphate ions, which were then reacted with ammonium vanadate (V), hexaammonium heptamolybdate, and nitric acid to produce phosphorus vanadomolybdate, which was then measured from the absorbance of the product.

[0037] (2) Method for preparing slurry organic waste solid fertilizer The above-mentioned Awamori distillation residue (manufactured by Zuisen Shuzo Co., Ltd.), ferrous sulfate heptahydrate (manufactured by Hayashi Pure Chemical Industries Co., Ltd.), magnesium sulfate (anhydrous) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), zinc sulfate heptahydrate (manufactured by Kanto Chemical Co., Ltd.), copper (II) sulfate pentahydrate (manufactured by Kanto Chemical Co., Ltd.), manganese (II) sulfate pentahydrate (manufactured by Kishida Chemical Co., Ltd.), boric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and ammonium sulfate (manufactured by Kanto Chemical Co., Ltd.) were added in predetermined amounts and completely dissolved. 1 g (1 ml) of this was collected and poured into a tray, to which 2 g of hemihydrate gypsum FT-2 (manufactured by Noritake Co., Ltd.) was added, mixed uniformly, and allowed to stand at room temperature. In order to prevent solidification due to natural drying, the mixture was placed in a sealed container together with a container containing water and allowed to stand. The amounts of each component added and the test results are shown in Table 2. (3) Solidification test At regular intervals, a cotton swab was pressed against the surface of the mixture in the tray, and solidification was evaluated based on whether the cotton swab left an imprint. The time it took for solidification to occur was recorded, and if the mixture had not solidified after 48 hours, it was rated as x. (4) Storage stability test of solid fertilizer After the solidification test, the obtained solid fertilizer was left to stand at room temperature for one week, and the presence or absence of decay, mold, or unpleasant odor was evaluated. (Rating: Content) ×: Rot, mold, or foul odor occurred. 〇: No decay, mold or bad odor occurred

[0038] [Table 2]

[0039] As shown in Table 2, when magnesium sulfate, manganese sulfate, ferrous sulfate, copper sulfate, zinc sulfate, or ammonium sulfate was added to awamori distillation residue, which is a slurry-like organic waste that contains water-soluble organic acids, water-soluble nitrogen, and water-soluble phosphorus and is highly putrefactive, it was solidified in a short time, and the resulting solid fertilizer also had good storage stability. [Industrial Applicability]

[0040] According to the present invention, by dissolving magnesium sulfate, manganese sulfate, iron sulfate, copper sulfate, zinc sulfate, and ammonium sulfate in slurry organic waste that is rich in components useful for plant growth, such as water-soluble organic acids, water-soluble nitrogen, and water-soluble phosphorus, and quickly solidifying the waste with gypsum hemihydrate, it is possible to produce a solid fertilizer that is enriched with minerals such as calcium, magnesium, iron, copper, zinc, and manganese while preventing decay, and this makes it possible to effectively utilize slurry organic waste that has previously been treated as industrial waste.< / ph>

Claims

1. A fertilizer obtained by adding one or more sulfates selected from the group consisting of magnesium sulfate, manganese sulfate, iron sulfate, copper sulfate, zinc sulfate and ammonium sulfate to a slurry-like organic waste containing one or more substances selected from the group consisting of water-soluble organic acids, water-soluble nitrogen and water-soluble phosphoric acid, and then adding hemihydrate gypsum to solidify the mixture.

2. 2. The fertilizer according to claim 1, wherein 50 parts by mass or more and less than 500 parts by mass of hemihydrate gypsum is added to 100 parts by mass of a slurry-like organic waste containing one or more selected from the group consisting of a water-soluble organic acid, a water-soluble nitrogen, and a water-soluble phosphoric acid.

3. 3. The fertilizer according to claim 1 or 2, wherein the sulfate is added so that the total mass content of sulfate ions in the sulfate is 0.1 to less than 50 times the total mass content of water-soluble organic acid, water-soluble nitrogen, and water-soluble phosphate contained in the slurry organic waste.

4. 3. The fertilizer according to claim 1 or 2, wherein the slurry organic waste containing one or more selected from the group consisting of water-soluble organic acids, water-soluble nitrogen and water-soluble phosphoric acid is a fermentation stillage of distilled liquor.

5. A method for producing a fertilizer, comprising the steps of adding one or more sulfates selected from the group consisting of magnesium sulfate, manganese sulfate, iron sulfate, copper sulfate, zinc sulfate and ammonium sulfate to a slurry-like organic waste containing one or more sulfates selected from the group consisting of water-soluble organic acids, water-soluble nitrogen and water-soluble phosphoric acid, and then adding gypsum hemihydrate to solidify the mixture.

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