Organic waste treatment equipment, organic waste treatment method, and organic waste utilization equipment

Abstract

The present invention provides an organic waste treatment apparatus and organic waste treatment method using methane fermentation, which eliminates the need to dispose of oily sludge derived from the organic waste of a building to an external location, eliminates the need for pretreatment to decompose a portion of the oil contained in the organic waste of a building, and reduces the amount of auxiliary materials supplied from outside the building. [Solution] Plants cultivated using methane fermentation digestate are supplied to adjust the ratio of the concentration of n-hexane extractable substances in the raw material in the methane fermentation tank to the loss on ignition.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an organic waste treatment apparatus, an organic waste treatment method, and organic waste utilization facilities. BACKGROUND ART

[0002] As an organic waste treatment apparatus attached to a building, a treatment apparatus using methane fermentation has high utility from the perspective that generated biogas can be utilized as fuel for a power generation apparatus or a boiler. For example, Patent Document 1 discloses an organic waste treatment apparatus using methane fermentation, which does not require discharging oil-containing sludge derived from organic waste of a single building to the outside, and does not require a pretreatment for decomposing part of the oil contained in the organic waste of the single building.

[0003] While methane fermentation generates methane fermentation digestate in addition to biogas, a method of utilizing the methane fermentation digestate as a fertilizer for plant cultivation is known. For example, Patent Documents 2 to 4 disclose methods of cultivating floating plants using methane fermentation digestate. Patent Document 4 discloses that floating plants cultivated using methane fermentation digestate are used as a raw material for methane fermentation. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0004] PATENT DOCUMENT 1 Japanese Unexamined Patent Application Publication No. 2021-122772 PATENT DOCUMENT 2 Japanese Unexamined Patent Application Publication No. 2006-305467 PATENT DOCUMENT 3 International Publication No. 2017 / 026370 PATENT DOCUMENT 4 Japanese Unexamined Patent Application Publication No. 2007-007582 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] The organic waste treatment device disclosed in Patent Document 1 optimizes the ratio of n-Hex concentration to loss on ignition (n-Hex concentration / loss on ignition) of raw materials in the methane fermentation tank by supplying auxiliary materials with a low oil concentration, thereby eliminating the need for external disposal of oily sludge and pretreatment for oil decomposition. However, the auxiliary materials with a low oil concentration are supplied from outside the building to which the organic waste treatment device is installed.

[0006] This disclosure was made under the circumstances described above. The present disclosure aims to provide an organic waste treatment apparatus and organic waste treatment method using methane fermentation, which eliminates the need to dispose of oily sludge derived from the organic waste of a building to an external location, eliminates the need for pretreatment to decompose a portion of the oil contained in the organic waste of a building, and reduces the amount of auxiliary materials supplied from outside the building. [Means for solving the problem]

[0007] The means for solving the aforementioned problem include the following embodiments.

[0008] <1> An organic waste treatment device attached to a building, A methane fermentation tank that performs methane fermentation using organic waste generated from the aforementioned building and auxiliary materials as raw materials, A plant cultivation facility that cultivates plants using methane fermentation digestate generated in the aforementioned methane fermentation tank, The methane fermentation tank includes an adjustment unit that adjusts the ratio of the concentration of n-hexane extractable substances in the raw material to the loss on ignition, The aforementioned auxiliary materials include plants cultivated by the plant cultivation equipment. Organic waste treatment equipment. <2> The organic waste generated from the building includes a first organic waste generated from the building that contains oil, and a second organic waste generated from the building that has a lower oil concentration than the first organic waste. <1> The organic waste treatment equipment described below. <3> The first organic waste is organic waste derived from kitchen wastewater, and the second organic waste is kitchen scraps or organic waste derived from kitchen scraps. <2> The organic waste treatment equipment described below. <4> The auxiliary materials include organic waste supplied from outside the building, which has a lower oil concentration than the second organic waste. <2> or <3> The organic waste treatment equipment described below. <5> The adjustment unit is an adjustment unit that adjusts the ratio of the concentration of n-hexane extractable substances in the raw material of the methane fermentation tank to the loss on ignition to a range of 0.2 to 0.4. <1> ~ <4> An organic waste treatment device as described in any one of the following.

[0009] <6-1> A method for processing organic waste generated from buildings, A methane fermentation process is carried out using organic waste generated from the aforementioned building and auxiliary materials as raw materials. A plant cultivation process in which plants are grown using the methane fermentation digestate generated in the aforementioned methane fermentation process, The process includes an adjustment step to adjust the ratio of the n-hexane extractable substance concentration to the loss on ignition of the raw materials for the methane fermentation process, The aforementioned auxiliary materials include plants cultivated in the aforementioned plant cultivation process. Methods for disposing of organic waste. <6-2> The organic waste treatment method according to <6-1>, wherein the organic waste generated from the building includes a first organic waste generated from the building and containing oil, and a second organic waste generated from the building and having a lower oil concentration than the first organic waste. <6-3> The method for treating organic waste according to <6-2>, wherein the first organic waste is organic waste derived from kitchen wastewater, and the second organic waste is kitchen scraps or organic waste derived from kitchen scraps. <6-4> The auxiliary material comprises organic waste that is supplied from the outside of the building and has a lower oil concentration than the second organic waste, the organic waste treatment method according to <6-2> or <6-3>. <6-5> The adjustment step is a step of adjusting the ratio of the n-hexane extractable substance concentration to the ignition loss of the raw material in the methane fermentation tank to a range of 0.2 to 0.4, the organic waste treatment method according to any one of <6-1> to <6-4>.

[0010] <7> An organic waste utilization facility attached to a building, comprising: the organic waste treatment apparatus according to any one of <1> to <5>; and a biogas utilization apparatus that utilizes biogas generated in the methane fermentation tank of the organic waste treatment apparatus, the organic waste utilization facility. <8> A method for producing biogas from organic waste generated from a building and utilizing the biogas as an energy source for the building, the method comprising: the organic waste treatment method according to any one of <6-1> to <6-5>; and a biogas utilization method for utilizing biogas generated in the methane fermentation step of the organic waste treatment method, the organic waste utilization method. [Effects of the Invention]

[0011] The present disclosure provides an organic waste treatment apparatus and an organic waste treatment method by methane fermentation, which do not require oil-containing sludge derived from organic waste of a single building to be discharged to the outside, do not require a pretreatment for decomposing part of the oil contained in the organic waste of a single building, and can reduce the supply amount of auxiliary materials from the outside of the single building. [Brief Description of the Drawings]

[0012] [Figure 1] It is a schematic diagram of an example of a conventional organic waste treatment apparatus attached to a building. [Figure 2] This is a schematic diagram of an organic waste treatment device disclosed in Japanese Patent Publication No. 2021-122772. [Figure 3] This is a schematic diagram of one embodiment of the organic waste treatment apparatus of the present disclosure. [Figure 4] This is an example of an embodiment of an organic waste treatment apparatus disclosed in Japanese Patent Publication No. 2021-122772. [Figure 5] This is an estimate of the amount of plant cultivation in one embodiment of the organic waste treatment device described herein. [Modes for carrying out the invention]

[0013] Embodiments of the invention are described below. These descriptions and embodiments are illustrative and do not limit the scope of the invention.

[0014] In this disclosure, the numerical range indicated using "~" includes the numbers before and after "~" as the minimum and maximum values, respectively. In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced with the values ​​shown in the examples.

[0015] In this disclosure, the term "process" includes not only independent processes but also any process that cannot be clearly distinguished from other processes, provided that its intended purpose is achieved.

[0016] In this disclosure, "a single building" means a single building, and includes both buildings consisting of one structure and buildings consisting of multiple structures. Examples of a single building include commercial facilities, restaurants, amusement facilities, entertainment facilities, recreational facilities, lodging facilities, office facilities, medical facilities, nursing care facilities, and complex facilities that combine two or more of these. In this disclosure, the term "building" refers to a single building, that is, a complete set of buildings.

[0017] In this disclosure, n-hexane extractable material is referred to as "n-Hex," the concentration of n-hexane extractable material is referred to as "n-Hex concentration," and the ratio of n-hexane extractable material concentration to ignition loss is referred to as "n-Hex concentration / ignition loss." n-Hex concentration / ignition loss represents the magnitude of the n-Hex concentration with ignition loss as the unit amount. In this disclosure, the units for n-Hex concentration and loss on ignition are "mg / kg".

[0018] In this disclosure, the fact that one organic substance has a lower oil concentration than other organic substances is equivalent to the fact that the n-Hex concentration / loss on ignition value of one organic substance is lower than the n-Hex concentration / loss on ignition value of the other organic substances. The requirement that one organic substance has a lower oil concentration than the other organic substance only needs to be met when the two organic substances are mixed. If the two organic substances are mixed in a methane fermentation tank, the requirement only needs to be met when they are supplied to the methane fermentation tank; if the two organic substances are mixed in a tank other than the methane fermentation tank, the requirement only needs to be met when they are supplied to that tank.

[0019] <Organic waste treatment equipment, organic waste treatment method> The organic waste treatment device described herein is an organic waste treatment device attached to a building, and is a device that ferments organic waste generated from the building into methane.

[0020] The organic waste treatment apparatus of this disclosure comprises a methane fermentation tank, a plant cultivation facility for cultivating plants using methane fermentation digestate generated in the methane fermentation tank, and an adjustment unit for adjusting the n-Hex concentration / ignition loss value of the raw materials in the methane fermentation tank.

[0021] The organic waste treatment device of this disclosure performs methane fermentation in a methane fermentation tank using a mixture of organic waste generated from buildings and auxiliary materials as raw materials.

[0022] The organic waste treatment device of this disclosure does not require the disposal of oily sludge derived from the organic waste of a building to the outside, nor does it require pretreatment to decompose a portion of the oil contained in the organic waste of a building, by using auxiliary materials with a low oil concentration and optimizing the n-Hex concentration / ignition loss value of the raw materials in the methane fermentation tank. The organic waste treatment device described herein reduces the amount of auxiliary materials supplied from outside a building by cultivating plants using methane fermentation digestate and using the plants as part or all of the auxiliary materials for methane fermentation.

[0023] The auxiliary materials are substances supplied to the methane fermentation tank for the purpose of optimizing the n-Hex concentration / ignition loss value of the raw materials in the methane fermentation tank of the organic waste treatment device of the present disclosure. The auxiliary materials include plants grown in the plant cultivation equipment of the organic waste treatment device of this disclosure, that is, plants grown using methane fermentation digestate. The plants have a low oil content and are suitable as auxiliary materials for optimizing the n-Hex concentration / ignition loss value of the raw materials in the methane fermentation tank.

[0024] In this disclosure, "plants" include plants themselves and processed products of plants. Examples of plant processing include cutting, crushing, dehydration, drying, and combinations thereof.

[0025] In this disclosure, "plant" means a broad term including algae and phytoplankton. The type of plant is not limited as long as it can be cultivated using methane fermentation digestate. The plant cultivation facility may cultivate one or more species of plants.

[0026] The plants may be land plants, aquatic plants, algae, or phytoplankton. Land plants are cultivated using a liquid fertilizer containing methane fermentation digestate. Aquatic plants, algae, and phytoplankton are cultivated in a growing solution containing methane fermentation digestate.

[0027] As for plants, aquatic plants, algae, and phytoplankton are preferred from the viewpoint of being able to effectively utilize not only methane fermentation digestate but also other liquids generated from organic waste treatment equipment in large quantities. Specific examples of aquatic plants include floating plants (e.g., duckweed, water hyacinth, bladderwort, hornwort, etc.), floating-leaved plants (e.g., water chestnut, giant water lily, water lily, etc.), emergent plants (e.g., reeds, cattails, wild rice, lotus, etc.), and submerged plants (e.g., water crowfoot, hydrangea, charophyte, etc.). Specific examples of algae and phytoplankton include Chlorella, Spirulina, and Euglena.

[0028] A good example of a suitable plant is duckweed (e.g., water hyacinth, duckweed, etc.). Duckweed is highly tolerant of polluted water and can grow in methane fermentation digestate. Duckweed multiplies rapidly, doubling or tripling in weight in a week. Duckweed is inexpensive to cultivate.

[0029] The auxiliary materials may also include organic waste supplied from outside the building, which has a low oil content. The auxiliary materials supplied from outside the building should preferably be organic waste with a lower oil concentration than the organic waste generated from the building, preferably organic waste with a lower oil concentration than the first type of organic waste described later, and more preferably organic waste with a lower oil concentration than the second type of organic waste described later. From the viewpoint of reducing the amount of auxiliary materials supplied from outside the building, the lower the oil concentration, the better.

[0030] Specific examples of auxiliary materials supplied from outside the building include dried kitchen waste (eco-feed), waste sugar liquid (e.g., organic waste liquid generated from canning factories), breadcrumbs, waste paper (e.g., cardboard), waste starch, rice flour from old rice, waste sugar, tofu lees (okara), seaweed (e.g., sea lettuce), waste molasses, waste glycerin, etc.

[0031] Typical examples of organic waste generated from buildings equipped with the organic waste treatment equipment described in this disclosure are the following two substances. • Primary organic waste containing oil, generated from buildings (e.g., organic waste derived from kitchen wastewater) • Secondary organic waste generated from buildings with a lower oil concentration than primary organic waste (e.g., kitchen waste or organic waste derived from kitchen waste)

[0032] The following describes the organic waste treatment apparatus of this disclosure, using the example of treating kitchen wastewater and food scraps generated in the kitchen of a restaurant in a multi-purpose commercial facility, with reference to the drawings, and comparing it with an example of a conventional organic waste treatment apparatus and an organic waste treatment apparatus disclosed in Japanese Patent Application Publication No. 2021-122772.

[0033] Figure 1 is a schematic diagram of an example of a conventional organic waste treatment system attached to a multi-purpose commercial facility. This organic waste treatment system is An oil-water separator tank 12 (a so-called grease trap) and a pressurized flotation device 14 for treating kitchen wastewater 10, A mixing tank 26 (also called a raw material tank) mixes the oily solids 40 of kitchen wastewater 10 with kitchen waste 20, A methane fermentation tank 28 that generates biogas 60 by performing methane fermentation using oil-containing solids 40 and food waste 20 as raw materials, The system includes an aerobic treatment tank 18 that uses aerobic bacteria to treat the liquid 42 discharged from the pressurized flotation device 14 and the digestate 44 generated in the methane fermentation tank 28 to produce treated water 46, and all parts are connected to each other by piping. Each of the above-mentioned parts is a known device in the field of this technology.

[0034] In the organic waste treatment system shown in Figure 1, kitchen wastewater 10 is treated in an oil-water separator 12, generating sediment 48, which becomes oil-containing sludge 50 (so-called GT scum). The oil-containing sludge 50 has a high oil concentration, and if it is introduced into the methane fermentation tank 28, methane fermentation will be inhibited. To avoid the inhibition of methane fermentation, the oil-containing sludge 50 is transported outside the complex commercial facility where the organic waste treatment device is installed and processed there.

[0035] Conventional organic waste treatment systems either dispose of oily sludge derived from kitchen wastewater outside the building, or treat organic waste generated from the building by providing a pretreatment tank (heat treatment tank or enzyme treatment tank) (not shown) that partially decomposes the oil in the kitchen wastewater. In other words, conventional organic waste treatment systems either remove a portion of the oil in the kitchen wastewater as oily sludge, or decompose a portion of the oil in the kitchen wastewater upstream of the methane fermentation tank, thereby optimizing the n-Hex concentration / ignition loss value of the raw materials in the methane fermentation tank.

[0036] Figure 2 is a schematic diagram of an organic waste treatment device disclosed in Japanese Patent Publication No. 2021-122772. This organic waste treatment device is A solids recovery device 16 that dewaters kitchen wastewater 10 to obtain oily solids 40, A mixing tank 26 (also called a raw material tank) mixes oil-containing solids 40 and kitchen waste 20, A methane fermentation tank 28 that generates biogas 60 by performing methane fermentation using oil-containing solids 40, kitchen waste 20, and auxiliary materials 30 as raw materials, An aerobic treatment tank 18 that treats the liquid 42 discharged from the solids recovery device 16 and the digestate 44 generated in the methane fermentation tank 28 with aerobic bacteria to produce treated water 46, The system includes an adjustment unit 32 that adjusts the n-Hex concentration / ignition loss value of the raw material in the methane fermentation tank 28, and each part is connected to the others by piping.

[0037] In the organic waste treatment apparatus shown in Figure 2, the adjustment unit 32 adjusts the supply amount of auxiliary materials 30 to the methane fermentation tank 28, thereby optimizing the n-Hex concentration / ignition loss value of the raw materials in the methane fermentation tank 28. This makes it possible to treat the entire amount of oily solids 40 obtained by dewatering kitchen wastewater 10. Therefore, the organic waste treatment device shown in Figure 2 does not require a device for disposing of oily sludge derived from kitchen wastewater 10 to the outside, nor does it require a pretreatment tank (heat treatment tank or enzyme treatment tank) for kitchen wastewater 10.

[0038] Figure 3 is a schematic diagram of one embodiment of the organic waste treatment apparatus of the present disclosure. The organic waste treatment apparatus is A solids recovery device 16 that dewaters kitchen wastewater 10 to obtain oily solids 40, A mixing tank 26 (also called a raw material tank) mixes oil-containing solids 40 and kitchen waste 20, A methane fermentation tank 28 that generates biogas 60 by performing methane fermentation using oil-containing solids 40, kitchen waste 20, auxiliary materials 30A and 30B as raw materials, A plant cultivation facility 80 that cultivates plants 84 using digestate 44 produced in a methane fermentation tank 28, A digestate concentration adjustment unit 70 adjusts the concentration of the digestate 44 that is transferred from the methane fermentation tank 28 to the plant cultivation equipment 80, A plant storage tank 90 for storing plants 84 cultivated by the plant cultivation equipment 80, An aerobic treatment tank 18 treats the liquid 42 discharged from the solids recovery device 16, the excess digestate 44, the wastewater 82 discharged from the plant cultivation equipment 80, and the wastewater 92 discharged from the plant storage tank 90 with aerobic bacteria to produce treated water 46. An adjustment unit 32 adjusts the n-Hex concentration / ignition loss value of the raw material in the methane fermentation tank 28, It is equipped with these features, and each part is connected to the others by piping.

[0039] In the organic waste treatment apparatus shown in Figure 3, the adjustment unit 32 adjusts the supply amounts of auxiliary materials 30A and 30B to the methane fermentation tank 28, thereby optimizing the n-Hex concentration / ignition loss value of the raw material in the methane fermentation tank 28. This makes it possible to treat the entire amount of oily solids 40 obtained by dewatering kitchen wastewater 10. Therefore, the organic waste treatment device shown in Figure 3 does not require a device for disposing of oily sludge derived from kitchen wastewater 10 to the outside, or a pretreatment tank (heat treatment tank or enzyme treatment tank) for kitchen wastewater 10.

[0040] Auxiliary material 30A is plant 84 and / or a processed product of plant 84. Auxiliary material 30B is an auxiliary material supplied from outside the building. Auxiliary material 30B is used as a raw material for methane fermentation when the supply of auxiliary material 30A is insufficient. Auxiliary material 30B is not used if the n-Hex concentration / ignition loss value of the raw material in the methane fermentation tank 28 can be appropriately adjusted using only auxiliary material 30A. Therefore, the organic waste treatment device shown in Figure 3 can reduce the amount of auxiliary material 30B supplied from an external source.

[0041] The organic waste treatment device shown in Figure 3 cultivates plants 84 using at least a portion of the digestate 44 generated in the methane fermentation tank 28 in order to obtain auxiliary materials 30A. If there is an excess of digestate 44, the excess digestate 44 is transferred to the aerobic treatment tank 18.

[0042] The following describes the various parts of the organic waste treatment device shown in Figure 3.

[0043] The solids recovery device 16 is a device that dewaters kitchen wastewater 10 to obtain oily solids 40. Examples of the solids recovery device 16 include a device that combines an oil-water separator (a so-called grease trap), a pressurized flotation device, and a sediment collection device to recover the floating oil and the settled oil. Kitchen wastewater 10 is transferred from the kitchen to a solids recovery device 16 and dewatered. The oily solids 40 of the kitchen wastewater 10 are transferred to a mixing tank 26, and the liquids 42 of the kitchen wastewater 10 are transferred to an aerobic treatment tank 18. Some or all of the oily solids 40 may be transferred directly to a methane fermentation tank 28. The oily solids 40 of the kitchen wastewater 10 are the first organic waste. The oily solids 40 of the kitchen wastewater 10 may be separated into, for example, floating oil and settled oil and collected separately, and after collection they may be transferred separately to the mixing tank 26 or the methane fermentation tank 28 (see Figure 4. Pressurized floating scum corresponds to floating oil, and GT scum corresponds to settled oil). In this case, the floating oil and settled oil constitute the first organic waste.

[0044] The mixing tank 26 mixes the oily solids 40 (i.e., first organic waste) and kitchen waste 20 (i.e., second organic waste) of the kitchen wastewater 10. In the mixing tank 26, some or all of the auxiliary material 30A may be further mixed in. In the mixing tank 26, some or all of the auxiliary material 30B may also be further mixed in.

[0045] The mixing tank 26 is not essential, but it is desirable to include it from the standpoint of evenly distributing the oil content in the raw materials for methane fermentation. From the viewpoint of stirring the raw materials and evenly dispersing the oil, it is desirable that the mixing tank 26 be equipped with a stirring means. The capacity of the mixing tank 26 should ideally be large enough to store approximately 2 to 5 days' worth of organic waste, given that the amount of organic waste generated from the building fluctuates daily. The temperature inside the mixing tank 26 is, for example, 30°C to 40°C.

[0046] The methane fermentation tank 28 may have a configuration known in the present art. The methane fermentation method employed by methane fermentation tank 28 is not particularly limited; it may be a mesothermal fermentation method with a fermentation temperature of around 37°C or a high-temperature fermentation method with a fermentation temperature of around 55°C, and it may be a wet method with a relatively high moisture content or a dry method with a relatively low moisture content.

[0047] The plant cultivation equipment 80 includes, for example, a plant cultivation tank and a plant recovery device. In the plant cultivation tank, digestate 44 or a concentration-adjusted digestate 44 is used as a nutrient solution or liquid fertilizer. Drainage 82 generated from the plant cultivation equipment 80 (for example, part or all of the nutrient solution, or drainage from the cultivation soil) is transferred to the aerobic treatment tank 18.

[0048] The plant cultivation tank may be equipped with, as needed, lighting to promote photosynthesis, a temperature control device for the cultivation environment, a gas supply device to supply carbon dioxide to the nutrient solution, a nutrient solution purification device, liquid fertilizer piping, and an irrigation system. The cultivation area and volume of the plant cultivation tank, the temperature and sunlight for plant cultivation, and the number of days for plant cultivation are designed according to the type of plant.

[0049] The plant recovery device periodically recovers some of the plants 84 in the plant cultivation tank. The recovered plants 84 are transferred to the plant storage tank 90. ​​The plants 84 that are not recovered become parent plants for the next cultivation. Plant recovery devices are designed according to the morphology of the plants. Examples of plant recovery devices for floating plants include nets and net winding machines.

[0050] Any surplus plants 84 cultivated by the plant cultivation equipment 80 may be used, for example, for the decoration of a building, or may be offered for consumption or sale at a facility within the building.

[0051] The digestate concentration adjustment unit 70 is not essential, but it is desirable to include it from the standpoint of adjusting the concentrations of nitrogen, phosphorus, and potassium contained in the digestate 44 to concentrations suitable for plant cultivation. The digestate concentration adjustment unit 70 includes, for example, a measuring unit for measuring the component concentrations of the digestate 44, and a control unit for controlling the amount of diluent added based on the measurement results from the measuring unit. Examples of diluent include treated water 46, rainwater, well water, and tap water. In the digestate concentration adjustment unit 70, nutrients necessary for the growth of plants 84 that are lacking in the digestate 44 may be added to the digestate 44.

[0052] It is preferable that the digestate concentration adjustment unit 70 uses part or all of the treated water 46 as a diluent to adjust the concentration of the digestate 44. In this case, at least a portion of the treated water 46 is transferred to the digestate concentration adjustment unit 70, and the remainder of the treated water 46 is discharged to the outside (for example, into a sewer).

[0053] While the plant storage tank 90 is not essential, it is desirable to provide it in order to adjust the supply amount of auxiliary material 30A according to the amount of oily solids 40 and / or kitchen waste 20 generated. When the amount of oily solids 40 and / or kitchen waste 20 generated is small, it is possible to use a large amount of auxiliary material 30A as a substitute for oily solids 40 and / or kitchen waste 20, so it is desirable to store plants 84 or processed products of plants 84 in the plant storage tank 90. The plant storage tank 90 is desirable to provide, also from the perspective of preparing for fluctuations in the yield of the plants 84. The capacity of the plant storage tank 90 should preferably be large enough to store plants 84 or processed products of plants 84 equivalent to 2 to 5 days' worth of auxiliary materials 30A.

[0054] The plant storage tank 90 is preferably equipped with either or both a plant dewatering device and a plant drying device, and is a facility for storing plants 84 in a dewatered and / or dried state. The dewatering device or drying device may also be equipped with a plant cutting device or a plant crushing device. The wastewater 92 derived from plants 84 generated from the plant storage tank 90 is transferred to the aerobic treatment tank 18.

[0055] The aerobic treatment tank 18 is equipment for properly purifying liquid 42, digestate 44 not used in plant cultivation, wastewater 82 from plant cultivation, and wastewater 92 derived from plants 84. The aerobic treatment tank 18 may have a configuration known in the art.

[0056] It is desirable that part or all of the treated water 46 is used to adjust the concentration of the digestate 44 in the digestate concentration adjustment unit 70. Part or all of the treated water 46 may be discharged into the sewer system.

[0057] The adjustment unit 32 is a device that adjusts the supply amounts of auxiliary materials 30A and 30B to the methane fermentation tank 28 according to the amount of organic waste generated from the building. The adjustment unit 32 comprises, for example, a first adjustment unit and a second adjustment unit, the first adjustment unit adjusting the supply amount of auxiliary material 30A to the methane fermentation tank 28, and the second adjustment unit adjusting the supply amount of auxiliary material 30B to the methane fermentation tank 28.

[0058] The supply of auxiliary material 30A to the methane fermentation tank 28 may be by direct supply to the methane fermentation tank 28 or by indirect supply via the mixing tank 26. The "amount of auxiliary material 30A supplied to the methane fermentation tank 28" is the sum of the amount supplied directly and the amount supplied indirectly. The supply of auxiliary material 30B to the methane fermentation tank 28 may be by direct supply to the methane fermentation tank 28 or by indirect supply via the mixing tank 26. The "amount of auxiliary material 30B supplied to the methane fermentation tank 28" is the sum of the amount supplied directly and the amount supplied indirectly. The adjustment unit 32 adjusts the direct and indirect supply amounts of auxiliary materials 30A and 30B to optimize the n-Hex concentration / ignition loss value of the raw materials in the methane fermentation tank 28.

[0059] The n-Hex concentration / loss on ignition ratio of the raw material is an indicator of the oil content of the raw material, and the higher the oil content, the higher the value. On the other hand, methane fermentation becomes more difficult as the oil content of the raw material increases, so there is a tendency for methane fermentation to become more difficult as the n-Hex concentration / loss on ignition ratio of the raw material increases. From the viewpoint of stable continuous operation of methane fermentation tanks and organic waste treatment equipment, it is preferable that the n-Hex concentration / ignition loss value of the raw material in the methane fermentation tank be 0.4 or less. This is based on the results of the [examination of the upper limit of n-Hex concentration / ignition loss] disclosed in paragraphs 0037 to 0039 and Table 1 and Figure 3 of Japanese Patent Application Publication No. 2021-122772.

[0060] As disclosed in Japanese Patent Publication No. 2021-122772, from the viewpoint of stable continuous operation of the methane fermentation tank and the organic waste treatment device, it is preferable that the n-Hex concentration / ignition loss value of the raw material in the methane fermentation tank be low, and preferably 0.4 or less. On the other hand, lowering the n-Hex concentration / loss on ignition value of the raw materials in the methane fermenter requires a larger amount of auxiliary materials, which leads to increased plant cultivation costs and the cost of procuring auxiliary materials from external sources. From the viewpoint of suppressing the amount of auxiliary materials, it is preferable that the n-Hex concentration / loss on ignition value of the raw materials in the methane fermenter be 0.2 or higher. Therefore, in the organic waste treatment apparatus of the present disclosure, the adjustment unit preferably adjusts the n-Hex concentration / ignition loss value of the raw material in the methane fermentation tank to a range of 0.2 to 0.4, more preferably to a range of 0.25 to 0.38, and even more preferably to a range of 0.28 to 0.35.

[0061] The adjustment unit 32 includes, for example, a calculation unit that predicts the n-Hex concentration / ignition loss value of the raw materials in the methane fermentation tank 28 based on the amount of organic waste generated from the building and the n-Hex concentration and ignition loss of each material supplied to the methane fermentation tank 28, and a control unit that controls the amount of auxiliary materials 30A and auxiliary materials 30B supplied to at least one of the mixing tank 26 and the methane fermentation tank 28 based on the prediction results of the calculation unit, and maintains the n-Hex concentration / ignition loss value of the raw materials in the methane fermentation tank 28 within a preset range (for example, 0.2 to 0.4).

[0062] Although not shown in Figure 3, the organic waste treatment device may also have a disposer and a solid-liquid separator as equipment for treating food waste. In this case, the food waste is fed into the disposer and crushed. The crushed food waste is transported through piping by transport water (e.g., tap water) to the solid-liquid separator, where it is separated into solid and liquid components. The solid component (organic waste derived from food waste, i.e., second organic waste) is transported to the mixing tank 26, and the liquid component is transported to the solid component recovery device 16 or the aerobic treatment tank 18.

[0063] The organic waste treatment apparatus of this disclosure, A methane fermentation process that uses organic waste generated from buildings and auxiliary materials as raw materials for methane fermentation, The plant cultivation process involves growing plants using the methane fermentation digestate produced in the methane fermentation process, The process includes an adjustment step to adjust the n-Hex concentration / ignition loss value of the raw materials in the methane fermentation process. The auxiliary materials include plants grown in the plant cultivation process. An organic waste treatment method (the organic waste treatment method described herein) is implemented.

[0064] <Organic waste utilization facilities, organic waste utilization methods> The organic waste utilization equipment of this disclosure comprises an organic waste treatment device of this disclosure and a biogas utilization device that utilizes biogas generated in the methane fermentation tank of the organic waste treatment device. The organic waste utilization equipment described herein is attached to a building and is designed to produce biogas from organic waste generated from the building and to use it as an energy source for the building.

[0065] Biogas utilization equipment is not particularly limited and includes any known biogas utilization equipment. Examples of biogas utilization equipment include biogas-fueled power generators and biogas-fueled boilers. The biogas utilization system may include a biogas storage tower, a desulfurization system to remove hydrogen sulfide from the biogas, and other such equipment.

[0066] The organic waste utilization facility of this disclosure enables the implementation of an organic waste utilization method (the organic waste utilization method of this disclosure), which includes the organic waste treatment method of this disclosure and a biogas utilization method that utilizes biogas generated in the methane fermentation process of said organic waste treatment method.

[0067] Examples of biogas utilization include generating electricity using biogas as fuel, and heating water using biogas to produce hot water or steam. [Examples]

[0068] Paragraphs 0048 to 0050, as well as Table 2 and Figure 4 of Japanese Patent Publication No. 2021-122772, demonstrate that methane fermentation of high-oil waste is possible by supplying auxiliary materials.

[0069] Paragraphs 0051 to 0057, Table 3, and Figure 6 of Japanese Patent Publication No. 2021-122772 disclose "Example B" as an example of an embodiment of an organic waste treatment device. Figure 6 of Japanese Patent Publication No. 2021-122772 relating to "Example B" is shown as Figure 4 in this disclosure.

[0070] Figure 4 shows a disposer 22 and solid-liquid separator 24 for processing kitchen waste, an oil-water separator 12 and pressurized flotation device 14 for processing kitchen wastewater, a methane fermentation tank 28, and an adjustment unit 32 for adjusting the amount of auxiliary materials supplied to the methane fermentation tank 28. In this embodiment, the entire amount of GT scum is fed into the methane fermentation tank 28. In this embodiment, 55 kg / day of auxiliary materials is required to process the entire amount of GT scum while maintaining the upper limit of n-Hex concentration / ignition loss in the raw material at 0.35. In this embodiment, the amount of digestate generated in the methane fermentation tank 28 is 2.3 m³. 3 The amount of pressurized flotation water generated by the pressurized flotation device 14 is 305 m³ / day. 3 / day

[0071] Based on the above embodiment example, we will estimate the cost reduction effect of external auxiliary materials when plants are cultivated using methane fermentation digestate and the plants are used as auxiliary materials.

[0072] (1) Assumptions for the calculation • Cultivate duckweed. • Use the entire amount of digestate and pressurized flotation water as the duckweed cultivation solution. The large-scale cultivation methods, growth rate, and VS (Volatile Solids) levels of duckweed will be determined by referring to Satoshi Matsumoto, "Nutrient Absorption and Utilization by Duckweed" (Chemistry and Biology: Journal of the Japan Society for Bioscience, Biotechnology, and Agrochemistry: Life, Food, Environment / edited by the Japan Society for Bioscience, Biotechnology, and Agrochemistry, 19(9)1981, pp. 594-600).

[0073] (2) Amount of duckweed cultivated • 5000L of nutrient solution can be used to cultivate 6kg of duckweed per day. • Duckweed cultivation solution = digestate + pressurized flotation treatment water = 2.3 m 3 / day+305m 3 / day=307.3m 3 / day • Amount of duckweed cultivated = 6 kg / day × 307.3 m 3 5000L = 368.76kg / day

[0074] (3) VS amount of duckweed • Assume the VS content of duckweed is 8% by mass. • VS amount of duckweed = 368.76 kg / day × 0.08 = 29.5 kg / day

[0075] The calculations for (2) and (3) are shown in Figure 5. 29.5 kg / day of duckweed-derived auxiliary material can be supplied to the methane fermentation tank.

[0076] (4) Effect of reducing external auxiliary materials • External auxiliary material costs = 500 yen / kg (purchase costs and labor costs based on actual projects) • Reduced external auxiliary material costs = 500 yen / kg × 29.5 kg / day = 14,750 yen / day

[0077] By replacing 29.5 kg / day of the necessary auxiliary materials with duckweed-derived auxiliary materials, a cost reduction of 14,750 yen / day in external auxiliary materials can be expected. [Explanation of Symbols]

[0078] 10 Kitchen drainage 12 Oil / water separation tank 14 Pressurized levitation device 16. Solids recovery device 18 Aerobic treatment tank 20 Kitchen waste 22 Garbage Disposal 24 Solid-liquid separator 26 Mixing tank 28 Methane fermentation tank 30, 30A, 30B auxiliary materials 32 Adjustment part 40 Oil-bearing solids 42 liquid components 44 Digestive juices 46. ​​Treated water 48. Precipitates 50 Oil-containing sludge 60 Biogas 70 Digestive fluid concentration adjustment section 80 Plant cultivation equipment 82 Drainage 84 Plants 90 Plant storage tanks 92 Drainage

Claims

1. An organic waste treatment device attached to a building, A methane fermentation tank that performs methane fermentation using organic waste generated from the aforementioned building and auxiliary materials as raw materials, A plant cultivation facility that cultivates plants using methane fermentation digestate generated in the aforementioned methane fermentation tank, The methane fermentation tank includes an adjustment unit that adjusts the ratio of the concentration of n-hexane extractable substances in the raw material to the loss on ignition, The aforementioned auxiliary materials include plants cultivated by the plant cultivation equipment. Organic waste treatment equipment.

2. The organic waste treatment apparatus according to claim 1, wherein the organic waste generated from the building includes a first organic waste generated from the building and containing oil, and a second organic waste generated from the building and having a lower oil concentration than the first organic waste.

3. The organic waste treatment apparatus according to claim 2, wherein the first organic waste is organic waste derived from kitchen wastewater, and the second organic waste is kitchen scraps or organic waste derived from kitchen scraps.

4. The organic waste treatment apparatus according to claim 2, wherein the auxiliary material includes organic waste supplied from outside the building and having a lower oil concentration than the second organic waste.

5. The organic waste treatment apparatus according to claim 1, wherein the adjustment unit is an adjustment unit that adjusts the ratio of the concentration of n-hexane extractable substances of the raw material in the methane fermentation tank to the loss on ignition to a range of 0.2 to 0.

4.

6. A method for processing organic waste generated from buildings, A methane fermentation process is carried out using organic waste generated from the aforementioned building and auxiliary materials as raw materials. A plant cultivation process in which plants are grown using the methane fermentation digestate generated in the aforementioned methane fermentation process, The process includes an adjustment step to adjust the ratio of the n-hexane extractable substance concentration to the loss on ignition of the raw materials for the methane fermentation process, The aforementioned auxiliary materials include plants cultivated in the aforementioned plant cultivation process. Methods for disposing of organic waste.

7. An organic waste utilization facility attached to a building, An organic waste treatment apparatus according to any one of claims 1 to 5, The system includes a biogas utilization device that utilizes biogas generated in the methane fermentation tank of the aforementioned organic waste treatment device. Facility for utilizing organic waste.

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