Waste treatment methods and waste treatment plants

Abstract

To enable a reduction in the concentration of chlorine derived from waste. [Solution] The waste treatment method comprises a fermentation drying step (step S10) in which waste 1 is aerobically fermented and dried to obtain a fermented dried product 20, and a desalination step (step S30) in which fermented dried fine granules 23, which are selected from the fermented dried product 20 and used as a fermentation aid 3 to be mixed with waste 1 when aerobically fermenting the waste 1, are desalined.

Description

Technical Field

[0001] The present invention relates to a waste treatment method and a waste treatment plant for subjecting waste in which food waste, paper, plastic, etc. generated in homes, restaurants, Japanese restaurants, hotels, supermarkets, etc. are mixed to aerobic fermentation drying treatment in order to recycle it as, for example, solid fuel (RDF), etc. In particular, the present invention relates to a waste treatment method and a waste treatment plant that can reduce the concentration of chlorine derived from waste and provide recycled products such as solid fuel (RDF) with a low chlorine concentration.

Background Art

[0002] Most of the food waste such as raw vegetables, fruits, and meats, papers, cloths, general waste including small plastics, combustible waste (burnable waste) such as domestic waste, etc. discharged from homes, industries that provide food and beverages such as restaurants, Japanese restaurants, hotels, supermarkets, etc., schools, and other workplaces are separately collected into several types by a method designated by the local government and incinerated at an incineration disposal site. However, in recent years, efforts have been made to reduce the incineration volume as much as possible by recycling general waste including organic waste such as food waste as resources from the perspective of environmental load, and attempts have been actively made to shift from incineration treatment to thermal recycling, chemical recycling, material recycling, etc. For example, as shown in Patent Document 1 and Patent Document 2, a method of fermenting and drying organic waste such as food waste in an aerobic environment and recycling it as a raw material for organic fertilizer or a raw material for solid fuel (Refuse Derived Fuel: RDF) is known.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

[0004] However, in the production of solid fuel (RDF) by aerobic fermentation and drying of general waste, including food waste, and then converting the fermented and dried material into solid fuel, salt derived from general waste such as food waste is present. Therefore, there are concerns about the corrosive effects on combustion equipment such as boilers, and a reduction in the chlorine concentration of solid fuel (RDF) is desired both for the maintenance of RDF combustion equipment and for its use as a highly versatile fuel.

[0005] In other words, RDF (Refuse Derived Fuel), a solid fuel produced from combustible general waste, has a high chlorine concentration due to high-chlorine plastics such as food wrap and inorganic chlorides such as salt derived from food waste. Its use is therefore limited to operators of high-chlorine compatible combustion boilers, large-scale paper mills and cement plants that can dilute it with large quantities of low-chlorine solid fuels such as RPF (Refuse Paper & Plastic Fuel).

[0006] Therefore, if the chlorine concentration of RDF (Refuse Derived Fuel) can be reduced, it will be possible to use it in combustion equipment such as small-scale boilers that do not have advanced exhaust gas treatment facilities. This will broaden the use and adoption of RDF, and enable its consumption even in areas that do not have nearby waste incineration facilities equipped with power generation equipment (waste-to-energy), leading to the spread of waste plants.

[0007] Conventionally, in order to reduce the chlorine concentration of solid fuel (RDF), when general waste is used as a raw material for the manufacture of RDF, attempts have been made to selectively remove polyvinyl chloride (PVC) after drying the general waste. However, such PVC removal devices are devices that detect the near-infrared absorption spectrum unique to PVC and discharge PVC out of the system by pneumatic transport. As they are optical devices, their spectra are easily affected by the color, shape, and size of the object being detected, as well as various impurities and contaminants in the surrounding environment (dust, dirt, etc.) and external factors (vibration, temperature). For this reason, there are limits to the PVC removal performance, removal accuracy, and removal rate, and it is difficult to sufficiently reduce the chlorine concentration of the raw material for the manufacture of solid fuel (RDF) by this method alone.

[0008] Therefore, the present invention aims to provide a waste treatment method and a waste treatment plant that enable the reduction of chlorine concentration derived from waste. [Means for solving the problem]

[0009] The waste treatment method of the invention of claim 1 involves aerobic fermentation and drying of waste in a fermentation drying step to obtain a fermented dried product, and then desalting the selected fermented dried product, which is selected from the fermented dried product and becomes a raw material for solid fuel, in a desalting step.

[0010] The above fermentation and drying process involves, for example, aerobic fermentation of waste materials in an airtight housing that allows for the introduction and discharge of air from the outside and controls the pressure to prevent odor leakage, thereby removing moisture and drying the waste using the heat generated by the fermentation. Preferably, the aerobic fermentation and drying of the waste materials are promoted by supplying air to the waste materials. Preferably, water is sprayed onto the waste materials during fermentation to promote uniform aerobic fermentation. Furthermore, preferably, a portion of the fermented and dried material is mixed with the waste materials as a fermentation aid, and more preferably, a desalted fermentation aid is mixed with the waste materials to efficiently aerobic fermentation and drying of the waste materials.

[0011] The above desalination process removes salts derived from waste. The selected fermented and dried material, which is separated from the fermented and dried material and becomes a raw material for solid fuel, may be desalinized by, for example, a water washing process to dissolve and remove inorganic chloride salts such as sodium chloride (NaCl), calcium chloride (CaCl2), and magnesium chloride (MgCl2) contained in the food waste (food residue), etc., in water. Alternatively, it may be removed by thermal decomposition of organic chlorine compound salts such as vinylidene chloride (PVDC) and vinyl chloride (PVC) contained in the waste food wrap, tablet packaging sheets, etc., by a heat treatment at a predetermined temperature, or both of the above may be performed.

[0012] The desalination treatment of the waste treatment method of the invention of claim 2 involves desalination by dissolving inorganic chloride salts such as sodium chloride derived from the waste in water through a water washing treatment of the sorted fermented and dried material to be used as a raw material for solid fuel, and desalination by thermal decomposition of organic chlorine compound salts such as vinylidene chloride and vinyl chloride through a heat treatment at 250°C or higher and 300°C or lower.

[0013] The above-mentioned washing treatment can be any treatment that dissolves water-soluble salts (soluble salts) of inorganic chlorides such as sodium chloride derived from waste. For example, this can be done by spraying water, water misting, or steam treatment on the selected fermented and dried material that will become a raw material for solid fuel, or by immersion treatment such as stirring or bubbling in a water tank. The above heat treatment can be any heat treatment at a temperature that is suitable for dehydrochlorinating organochlorine compounds such as vinylidene chloride and vinyl chloride derived from waste. The heating method is not particularly limited and may be electric heating using an electric heater, burner heating, superheated steam heating, or high-frequency induction heating. The above-mentioned watering treatment and heating treatment may be performed either after the watering treatment or after the heating treatment, but preferably, by performing the heating treatment after the watering treatment, the effect of reducing inorganic chloride salts such as sodium chloride can be increased with less energy consumption.

[0014] The waste treatment method of the invention of claim 3 further comprises a thermal decomposition step of heating at a temperature above 300°C and below 700°C after the heat treatment at a temperature of 250°C or higher and below 300°C. The above-described pyrolysis process involves heating the desalted, sorted, fermented, and dried material at a temperature exceeding 300°C but not exceeding 700°C. This high-temperature heat treatment (high-temperature treatment) causes the hydrocarbon components derived from the waste to be thermally decomposed into oil and carbonized.

[0015] The waste treatment plant according to claim 4 comprises a fermentation and drying section for aerobic fermentation and drying of waste to obtain a fermented and dried product, and a desalination means for desalting selected fermented and dried products that are selected from the fermented and dried product and become raw materials for solid fuel.

[0016] The above-mentioned fermentation and drying unit can be any unit that aerobically ferments waste and dries it using the heat of fermentation. For example, it is composed of an aerobic fermentation and drying apparatus equipped with an airtight housing that allows for the introduction and discharge of air from the outside by a fan (blower), etc., and controls the pressure to a negative pressure to prevent odor leakage. Preferably, it is equipped with a blower that supplies air to the waste, and air is blown onto the waste placed in the housing to promote the progress of aerobic fermentation and drying of the waste. Preferably, it is equipped with a watering means for spraying water on the waste during fermentation to promote uniform aerobic fermentation of the waste. Furthermore, preferably, a portion of the fermented and dried material is mixed with the waste as a fermentation aid, and more preferably, a desalted fermentation aid is mixed with the waste to efficiently aerobic ferment and dry the waste.

[0017] The above desalination method removes salts derived from waste. The selected fermented dried material, which is separated from the fermented dried material and becomes a raw material for solid fuel, may be desalinized by, for example, washing with water to dissolve and remove inorganic chloride salts such as sodium chloride (NaCl), calcium chloride (CaCl2), and magnesium chloride (MgCl2) contained in food waste (food residue) in the waste. Alternatively, salts of organochlorine compounds such as vinylidene chloride (PVDC) and vinyl chloride (PVC) contained in food wrap, tablet packaging sheets, etc. in the waste may be removed by thermal decomposition through heat treatment at a predetermined temperature, or both methods may be used.

[0018] The desalination means of the waste treatment plant according to claim 5 desalinates inorganic chloride salts such as sodium chloride derived from the waste by dissolving them in water through a water washing treatment of the sorted fermented and dried material to be used as a raw material for solid fuel, and also desalinates organic chlorine compound salts such as vinylidene chloride and vinyl chloride by thermal decomposition through a heat treatment at 250°C or higher and 300°C or lower.

[0019] The above-mentioned washing treatment can be any treatment that dissolves water-soluble salts (soluble salts) of inorganic chlorides such as sodium chloride derived from waste. For example, this can be done by spraying water, water misting, or steam treatment on the selected fermented and dried material that will become a raw material for solid fuel, or by immersion treatment such as stirring or bubbling in a water tank. The above heat treatment can be any heat treatment at a temperature that is suitable for dehydrochlorinating organochlorine compounds such as vinylidene chloride and vinyl chloride derived from waste. The heating method is not particularly limited and may be electric heating using an electric heater, burner heating, superheated steam heating, or high-frequency induction heating. The above-mentioned watering treatment and heating treatment may be performed either after the watering treatment or after the heating treatment, but preferably, by performing the heating treatment after the watering treatment, the effect of reducing inorganic chloride salts such as sodium chloride can be increased with less energy consumption.

[0020] The waste treatment plant of the invention according to claim 6 further comprises pyrolysis means for heating at a temperature exceeding 300°C and not exceeding 700°C after the heat treatment at 250°C or higher and 300°C or lower. The pyrolysis means heats the desalted sorted fermented product at a temperature exceeding 300°C and not exceeding 700°C. As long as the hydrocarbon components derived from the waste are pyrolyzed and converted into oil by this high-temperature heat treatment (high heat treatment), there is no particular limitation on the heating method, and it may be electric heating by an electric heater or the like, or a burner heating method, or a superheated steam method, or a high-frequency induction heating method.

Advantages of the Invention

[0021] According to the waste treatment method of the invention according to claim 1, in the fermentation drying step, the waste is aerobically fermented and dried to obtain a fermentation dried product, and in the desalting step, the sorted fermentation dried product selected from the fermentation dried product and used as a raw material for solid fuel is desalted to remove salts derived from the waste in the sorted fermentation dried product used as a raw material for solid fuel. In particular, in the desalting treatment by washing the sorted fermentation dried product with water, salts of inorganic chlorides such as sodium chloride (NaCl) contained in food residues, kitchen waste, etc. derived from the waste can be removed. Also, in the desalting treatment by heat treatment of the sorted fermentation dried product at a predetermined temperature, salts of organic chlorine compounds such as polyvinylidene chloride (PVDC) and polyvinyl chloride (PVC) contained in food wraps, tablet packaging sheets, etc. derived from the waste can be removed. Therefore, the salt concentration of the sorted fermentation dried product selected as the raw material for solid fuel from the fermentation dried product can be effectively reduced. Thus, it is possible to reduce the concentration of chlorine derived from the waste.

[0022] According to the waste treatment method according to the invention of claim 2, since the desalting treatment is performed by washing the sorted fermented dried product used as the solid fuel raw material with water and performing a heat treatment at 250°C or higher and 300°C or lower, salts of inorganic chlorides are removed by the washing treatment, and salts of organic chlorine compounds are removed by the heat treatment at a predetermined temperature. Therefore, in addition to the effects described in claim 1, the effect of reducing the chlorine concentration of the solid fuel raw material can be enhanced. Preferably, by performing the heat treatment at a predetermined temperature after performing the washing treatment, the removal efficiency of salts of inorganic chlorides can be increased, and the effect of reducing the chlorine concentration of the solid fuel raw material can be improved.

[0023] According to the waste treatment method according to the invention of claim 3, further, after the heat treatment at 250°C or higher and 300°C or lower, the hydrocarbon content in the sorted fermented dried product subjected to the desalting treatment is thermally decomposed by a thermal decomposition step of heating at a temperature exceeding 300°C and not exceeding 700°C, thereby generating pyrolysis oil (produced oil), and the residue of the sorted fermented dried product heated at a temperature exceeding 300°C and not exceeding 700°C also becomes a solid fuel raw material. Therefore, in addition to the effects described in claim 2, the use as a fuel can be expanded.

[0024] According to the waste treatment plant according to the invention of claim 4, the waste is aerobically fermented and dried by the fermentation drying treatment unit to obtain a fermented dried product, and the sorted fermented dried product selected from the fermented dried product by the desalting means and used as the solid fuel raw material is desalted, thereby removing salts derived from the waste in the sorted fermented dried product used as the solid fuel raw material. In particular, in the desalting treatment by washing the sorted fermented dried product with water, salts of inorganic chlorides such as sodium chloride (NaCl) contained in food residues, kitchen waste, etc. derived from the waste can be removed. Also, in the desalting treatment by heat treatment at a predetermined temperature of the sorted fermented dried product, salts of organic chlorine compounds such as polyvinylidene chloride (PVDC) and polyvinyl chloride (PVC) contained in food wraps, tablet packaging sheets, etc. derived from the waste can be removed. Therefore, the salt concentration of the sorted fermented dried product, which is the raw material of the solid fuel selected from the fermented dried product, can be effectively reduced. Thus, it is possible to reduce the concentration of chlorine derived from the waste.

[0025] According to the waste treatment plant of claim 5, the desalination means is carried out by washing the selected fermented and dried material used as solid fuel raw material with water and heating it at 250°C or higher and 300°C or lower. As a result, inorganic chloride salts are removed by the washing treatment, and organochlorine compound salts are removed by the heating treatment at a predetermined temperature. Therefore, in addition to the effects described in claim 4, the effect of reducing the chlorine concentration of the solid fuel raw material can be enhanced. Preferably, by performing the washing treatment followed by the heating treatment at a predetermined temperature, the efficiency of removing inorganic chloride salts can be increased, and the effect of reducing the chlorine concentration of the solid fuel raw material can be improved.

[0026] According to the waste treatment plant of claim 6, furthermore, after the heat treatment at 250°C or higher and 300°C or lower, the hydrocarbon components in the desalted sorted fermented dried material are thermally decomposed by a thermal decomposition means that heats the material at over 300°C and 700°C or lower, thereby producing thermal decomposition oil (produced oil), and the residue of the sorted fermented dried material heated at over 300°C and 700°C or lower can also be used as a raw material for solid fuel. Therefore, in addition to the effects described in claim 5, the range of uses as fuel can be expanded. [Brief explanation of the drawing]

[0027] [Figure 1] Figure 1 is a flowchart of the waste treatment method and waste treatment process in a waste treatment plant according to Embodiment 1 of the present invention. [Figure 2] Figure 2 is a conceptual diagram of the waste treatment method and the sorting and desalting treatment of fermented and dried materials in a waste plant according to Embodiment 1 of the present invention. [Figure 3] Figure 3 is a flowchart of the waste treatment method and waste treatment process in a waste treatment plant according to Embodiment 2 of the present invention. [Figure 4] Figure 4 is a conceptual diagram of the waste treatment method and the sorting and desalting treatment of fermented and dried materials in a waste plant according to Embodiment 2 of the present invention. [Figure 5] Figure 5 shows a flowchart of the waste treatment process in a waste treatment plant and a conceptual diagram of the desalination process according to Embodiment 3 of the present invention. [Modes for carrying out the invention]

[0028] Embodiments of the present invention will be described below with reference to the drawings. In these embodiments, identical symbols and reference numerals in the figures represent the same or corresponding functional parts, and therefore, redundant explanations will be omitted here.

[0029] [Embodiment 1] First, the overall flow of waste treatment in the waste treatment method and waste treatment plant of Embodiment 1 of the present invention will be explained with reference to Figures 1 and 2. The waste treatment method and waste treatment plant of Embodiment 1 are applied to waste recycling, which involves recycling waste 1 such as food waste, paper, cloth, and plastic discarded from ordinary households into waste-derived fuel (RDF) 211, etc.

[0030] Waste 1, which includes household or business general waste such as food waste, paper scraps, tree pruning waste, and plastics that are generated as combustible waste (combustible waste) in homes or businesses and collected and transported by garbage trucks, as well as organic waste such as food waste and animal and plant residues that are transported as industrial waste, enters the building of the waste treatment plant. First, in the crushing process (step S1), the garbage bags containing the food waste, paper, plastics, etc. of waste 1 are ruptured by a crusher. In addition, waste 1 is crushed and reduced in volume by coarse crushing or crushing. In the subsequent mixing step (step S2), the crushed and volume-reduced waste 1 is mixed with a bulk density adjusting material 2, which increases the volume by creating many aeration voids within the pile of waste 1, and a fermentation aid material 3 to which aerobic microorganisms are attached, and the bulk density is adjusted to be within a predetermined range to form fermentation material 10.

[0031] The bulk density adjusting material 2 to be mixed with the waste 1 can be any organic material of a predetermined size that can increase the volume of the waste 1 deposit and create aeration voids within the deposit. Preferably, an organic material that is water-absorbing, hygroscopic, and capable of supporting microorganisms can be used, such as wood chips or other woody materials, or solid fuel raw materials 210 selected from the fermented and dried product 20 described later, or RDF (Refuse Derived Fuel) of solid fuel 211 obtained by solidifying these, or RPF (Refuse Paper & Plastic Fuel) of solid fuel.

[0032] Wood chips and other wood-based materials, as well as solid fuel raw materials 210, are low-cost and readily support aerobic microorganisms, allowing for efficient aerobic fermentation and drying of waste 1 through repeated reuse. Therefore, it is possible to promote aerobic fermentation of waste 1 at low cost. In particular, as will be described later, wood-based materials 24 and solid fuel raw materials 210 selected from fermented dried products 20 obtained by fermenting and drying fermentation material 10 have a high content of decomposed products such as food waste, so heat generation (fermentation heat) due to aerobic fermentation by aerobic microorganisms can be expected, and a high effect of promoting the aerobic fermentation and drying of fermentation material 10 can be expected.

[0033] Furthermore, the fermentation aid 3 enhances the efficiency of aerobic fermentation drying of the waste 1, and is suitable for fermented dried material 20 that has undergone aerobic fermentation because it has a large number of aerobic microorganisms attached to it. In particular, in this embodiment 1, as will be described later, the fermentation aid 3 is selected from and desalted from fermented dried material 20 obtained by fermenting and drying fermentation material 10 containing waste 1. That is, as will be described later, fermented dried fine granules 23, which are separated and selected from the fermented dried material 20 by particle size and weight sorting, separately from those that become solid fuel raw materials 210 etc., are desalted and used as the fermentation aid 3, which is then returned to the aerobic fermentation process of fermentation material 10.

[0034] Next, the fermented material 10, which has been mixed with the waste 1 and the bulk density adjusting agent 2 and fermentation aid 3 to adjust to a predetermined bulk density, is loaded into a concrete housing of an aerobic fermentation drying apparatus, which serves as a fermentation drying processing unit, and is stored entirely or partially within the building. There, it is aerobically fermented and dried for a predetermined number of days as part of a fermentation drying process (step S10).

[0035] In this embodiment 1, the aerobic fermentation drying apparatus, which serves as the fermentation drying section, sprays water onto the fermentation material 10 that is placed in the housing. In this embodiment 1, wastewater discharged into the housing, i.e., wastewater seeping from the fermentation material 10 containing waste 1, excess water from spraying, etc., is collected, filtered, and the filtered water is reused to spray water onto the fermentation material 10 in the housing. In addition, wastewater discharged into the building from the waste 1, including the crushing of the waste 1 and the mixing process with the bulk density adjusting material 2 and fermentation aid material 3, is also collected, filtered, and the filtered water is reused to spray water onto the fermentation material 10 in the housing.

[0036] In other words, in the waste treatment plant of this embodiment 1, wastewater discharged into the housing, including the moisture contained in the waste 1 and the water sprayed into the housing where the waste 1 is aerobically fermented, is recovered from a drainage channel formed at the bottom of the housing. Similarly, wastewater discharged into the building is also recovered from a drainage channel formed at the bottom of the building and used as water for spraying the fermentation material 10 containing the waste 1 via a water storage tank and filter, thus preventing wastewater from being discharged to the outside.

[0037] Thus, in this embodiment of the aerobic fermentation drying apparatus, wastewater seeping from the waste 1 and excess water from the spraying are collected within the housing, and after removing foreign matter with a filter without being discharged to the outside, it is repeatedly circulated and used as spray water on the fermentation material 10 containing the waste 1. Since the wastewater generated within the housing contains aerobic microorganisms, the water sprayed as droplets also contains aerobic microorganisms, which allows for a uniform distribution of aerobic microorganisms to the fermentation material 10, thereby increasing the efficiency of the aerobic fermentation process. In other words, the spraying of water droplets allows the aerobic microorganisms contained in the droplets to penetrate and homogenize the entire fermentation material 1, enabling efficient aerobic fermentation treatment. In particular, since wastewater from within the housing and wastewater generated from buildings other than the housing are also collected and used for watering, the water necessary for aerobic microorganisms for the efficient aerobic fermentation treatment of the fermentation material 10 can be supplied at low cost, the amount of wastewater discharged to the outside can be reduced, and wastewater treatment equipment can be made smaller or even eliminated.

[0038] Furthermore, in the housing of the aerobic fermentation drying apparatus of this embodiment 1, oxygen is replenished by exchanging the discharge of air (odor) with the intake of fresh air from inside the building, and the temperature and negative pressure inside the housing are controlled to a predetermined level. In addition, an air circulation section is formed by drawing in indoor air from the top of the housing with a fan (blower), compressing that air, and blowing it out from the bottom of the housing, thereby circulating the air inside the housing and providing ventilation to the fermentation material 10 loaded inside the housing.

[0039] In this embodiment 1, the amount of air discharged from the housing of the aerobic fermentation drying apparatus is set to be greater than the amount of air input into the housing, and by maintaining negative pressure inside the housing, there is no possibility of odor escaping outside the housing. However, the air (odor) discharged from the housing is deodorized by a biological deodorizer via an air plenum chamber before being exhausted to the outside. In other words, the humid air (odor) discharged from the housing is sent from the housing to the air plenum room, where it is mixed with incoming air taken in from inside the building outside the housing, and then sent to the biological deodorizer of the deodorization equipment installed outside the building.

[0040] The biological deodorizer of this embodiment 1 is equipped with a biofilter made of a carrier such as wood chips to which aerobic microorganisms have adhered. Mixed air sent from the air plenum chamber is passed through the biofilter, and odor components contained in the mixed air are decomposed and deodorized by aerobic fermentation by aerobic microorganisms in the biofilter before being exhausted (released) to the outside, i.e., the outdoor atmosphere. In a biological deodorizer that deodorizes by digestion through biological treatment by aerobic microorganisms, the malodorous gases exhausted from the aerobic fermentation drying device are broken down into harmless substances such as CO2 and H2O, and SO4. - No. 3 - It is broken down into inorganic ions such as and released, but at this time, no residue requiring post-treatment is generated, and it is not incinerated, so CO2 and NO X Emissions are also minimized.

[0041] In this embodiment 1 of the biological deodorization device, water is sprayed onto the biofilter, and any excess water is recovered and reused for spraying. This ensures that the water necessary for the activity and growth of aerobic microorganisms attached to carriers such as wood chips that decompose and consume odors is uniformly added and replenished, thus achieving stable deodorization efficiency. In particular, since the excess water recovered after passing through the biofilter contains aerobic microorganisms, the water sprayed as droplets also contains aerobic microorganisms, allowing for a uniform distribution of aerobic microorganisms across the biofilter and increasing the digestion efficiency through aerobic fermentation. That is, the spraying of droplets of circulating water allows the aerobic microorganisms contained in the droplets to permeate and homogenize the entire biofilter, enabling efficient odor treatment. Furthermore, since the excess water is recovered and reused, the water necessary for aerobic microorganisms to maintain stable deodorization efficiency can be supplied at low cost, and since the excess water sprayed onto the biofilter is not discharged to the outside, wastewater treatment equipment can be reduced in scale or eliminated altogether.

[0042] Thus, in the waste treatment plant of this embodiment 1, waste 1 is processed inside a building that is always kept under negative pressure, and aerobic fermentation and drying of fermentation material 10 is carried out in a housing that is kept under a higher negative pressure than the outside, blocking the airflow from the outside to the inside and preventing odor leakage. The air (odor) inside the housing is deodorized by passing through an air plenum chamber to a bio-deodorizer installed outdoors, where it passes through a biofilter made of a carrier such as wood chips filled in a tank, and then exhausted into the atmosphere. Therefore, there is no emission of malodorous odors or uncontrollable odor leakage.

[0043] Incidentally, in the fermentation process by microorganisms in an aerobic fermentation drying apparatus (static type), for the first few days, bacteria, filamentous fungi, etc., actively decompose easily decomposable organic substances in the waste 1, such as proteins, amino acids, and sugars, raising the temperature of the waste 1 and, consequently, the housing. Once the easily decomposable substances are consumed and the temperature rises, thermophilic aerobic actinomycetes, etc., become involved in the decomposition of organic matter, and the decomposition of hemicellulose and cellulose begins, with the temperature reaching a maximum of 60°C to 80°C. This high-temperature environment kills various bacteria, thus ensuring the hygiene of the processed material. Pathogenic bacteria are usually sterilized at 55°C or higher for 3 days, preferably 65°C or higher for 48 hours or more. Subsequently, a moderate temperature range of 30°C to 50°C is maintained to further promote the decomposition of organic matter. After that, the amount of air taken in from outside the housing and into the housing is increased to promote cooling and drying.

[0044] Thus, in the fermentation and drying process (step S10), the decomposition of waste 1 by aerobic microorganisms and aerobic fermentation proceed, and drying also proceeds due to fermentation heat and aeration. In other words, in this fermentation and drying process (step S10), aerobic microorganisms such as bacteria and filamentous fungi consume oxygen and organic matter from waste 1, producing carbon dioxide and energy (heat). The heat generated here raises the temperature of the fermentation material 10 containing waste 1, and dries the fermentation material 10. Waste 1 with a normal composition (20% organic waste, 60% total moisture) is reduced to approximately half its volume through decomposition and moisture removal by fermentation and drying.

[0045] Then, the fermented and dried product 20, which has been aerobically fermented and dried in an aerobic fermentation drying apparatus, that is, the fermented and dried product 20 which has been aerobically fermented by aerobic microorganisms and dried by the heat of fermentation and aeration (air blowing), is, in this embodiment 1, as shown in Figures 1 and 2, passed by a wheel loader or the like, and in the subsequent sorting process (step S20), is sorted according to criteria such as size (particle size) and gravity (specific gravity) into predetermined oversized fermented and dried heavy product 21 which mainly contains wood material 24 used as bulk density adjusting material 2, predetermined oversized fermented and dried light product 22 which mainly becomes raw material 210 for solid fuel (RDF) 211, and predetermined undersized fermented and dried fine granules 23 which is mainly used as fermentation aid 3.

[0046] Specifically, in this embodiment 1, the fermented and dried material 20 is first sorted by weight (specific gravity) and particle size (particle size) using a particle size and weight sorter S, which utilizes buoyancy from a predetermined airflow and a sieve of a predetermined mesh size. In the particle size and weight sorter, particle size sorting is performed by combining a screen S such as a trommel screen, star screen, or vibrating screen with air sorting (weight sorting). At this time, the airflow introduced into the particle size and weight sorter is guided to a cyclone C, where the vortex flow pushes the debris downwards for removal, and the air from which the debris has been removed is discharged from the top of the cyclone C. It is also effective to use a fan to draw air in from the output side of the cyclone C.

[0047] This sorting machine separates the fermented and dried material 20 into a predetermined oversized (size that does not pass through a sieve with a predetermined mesh size) and a predetermined weight or more fermented and dried heavy material 21, which mainly consists of woody materials 24 such as large wood chips (wood stalks) that are reused as bulk density adjusting material 2; a predetermined oversized (size that does not pass through a sieve with a predetermined mesh size) and a predetermined weight or less fermented and dried light material 22, which mainly consists of decomposed materials such as paper, plastic, and food waste; and a predetermined undersized (size that passes through a sieve with a predetermined mesh size) fermented and dried fine granular material 23, which mainly consists of decomposed materials such as food waste.

[0048] The fermented and dried heavy material 21, which is of a predetermined oversize and weighs above a predetermined weight, sorted by a particle size and weight sorter, mainly consists of woody materials 24 such as large wood chips (wood stalks) used as bulk density adjusting material 2. Metals 310 such as iron are sorted and removed by magnetic sorting (step S21) using a magnetic separator M, and non-combustible materials 320 such as bottles, glass, ceramics, and stones are sorted and removed by manual sorting (manual sorting) (step S22). The remaining material after the removal of metals 310 and non-combustible materials 320 is recovered as woody materials 24 to be used as bulk density adjusting material 2 for the next batch of untreated waste 1 to be aerobically fermented, and is reused as bulk density adjusting material 2 for the waste 1 to be fermented and dried. Furthermore, metals such as iron 310, non-combustible materials such as bottles, glass, and ceramics 320, and polyvinyl chloride 330, which will be described later, that are removed in sorting processes such as magnetic sorting, manual sorting, and optical sorting described later, are recycled or disposed of.

[0049] Furthermore, the fermented and dried lightweight material 22, which is of a predetermined oversize and less than a predetermined weight, sorted by a particle size and weight sorter, mainly contains decomposed materials such as paper, plastics, and food waste. Metals such as iron 310 are sorted and removed by magnetic sorting by a magnetic separator M (step S24), and polyvinyl chloride 330 is sorted and removed by optical sorting using near-infrared spectroscopy by an optical separator U (step S25). The remaining material after the removal of metals 310 and polyvinyl chloride 330 becomes the solid fuel raw material 210 used for solid fuel (RDF) 211. The solid fuel raw material 210 can be easily transported to the solid fuel manufacturing process by, for example, compressing and packaging it with a baler (compression baler).

[0050] The solid fuel raw material 210 is mixed with a calorific value adjusting material such as dry plastic, wood, paper, or cloth in the subsequent solid fuel manufacturing process, crushed in a crusher, and further processed to remove non-combustible materials such as iron or stone as needed, and then molded in a molding machine to become solid fuel (RDF) 211. In the molding process, additives such as spoilage inhibitors are added as needed. Furthermore, odors and water vapor generated during the solid fuel manufacturing process, especially the molding process, can be sent to a biological deodorization device, where they are deodorized, and then exhausted outside. The resulting solid fuel (RDF) 211 has excellent transportability and storage properties, is easy to handle as fuel, and can be used for a variety of purposes (heating, power generation, etc.).

[0051] Furthermore, the fermented and dried fine granules 23 of a predetermined undersize, sorted by the sorting machine S, mainly contain decomposed products such as food waste. Therefore, they also contain starter cultures (aerobic microorganisms) that promote aerobic fermentation of the waste 1, and are recovered as suitable for use as a fermentation aid 3 that can efficiently promote aerobic fermentation and drying of the waste 1.

[0052] In particular, in this embodiment 1, the fermented and dried fine granules 23 of a predetermined undersize, sorted by the sorting machine S, are desalted in a desalting process (step S30) and then used as a fermentation aid 3 to be mixed with the untreated waste 1 for the next cycle.

[0053] Here, the inventors investigated the salt content in the fermented dried product 20 obtained by aerobic fermentation and drying of waste 1, and found that it contains a large amount of inorganic chlorides such as sodium chloride (NaCl), calcium chloride (CaCl2), and magnesium chloride (MgCl2) which are found in food waste (food residues), etc. Since such inorganic chlorides are mainly water-soluble chlorides, the inventors found that by washing the fermented dried granules 23 selected from the fermented dried product 20 with water, the water-soluble chlorides contained in the fermented dried granules 23 can be removed by dissolving them in water, and the salt concentration of the fermented dried granules 23 can be greatly reduced.

[0054] Furthermore, by washing the fermented and dried granules 23 with water, the salt concentration of the fermented and dried granules 23 is reduced. This means that even when the fermented and dried granules 23 are returned to the fermented and dried untreated fermented material 10 in the fermentation and drying process (step S10) and repeatedly used as a fermentation aid 3, salt concentration and accumulation do not occur in the fermented and dried product 20 obtained from the fermented and dried fermented material 10. This allows the salt concentration of the fermented and dried product 20 to be kept low, and stable fermentation and drying efficiency to be maintained. Consequently, the salt concentration of the solid fuel raw material 210 selected from the fermented and dried product 20 is also kept low. Therefore, it becomes possible to supply a solid fuel (RDF) 211 that is highly versatile and less likely to degrade combustion equipment such as boilers.

[0055] In other words, if "chlorine concentration of waste 1 / (1 - weight reduction rate)" < "chlorine concentration of fermentation aid 3" (weight reduction rate: {weight of fermentation material 10 - weight of fermented dried product 20} / weight of fermentation material 10), then in the fermentation drying process (step S10), the fermentation drying treatment of fermentation material 10 to which fermentation aid 3 has been added will result in salt concentration and accumulation in the fermented dried product 20. That is, if the salt concentration of fermentation aid 3 is higher than the salt concentration of waste 1 when the fermented dried granules 23, which is part of the fermented dried product 20, is returned (recycled) and reused as fermentation aid 3 mixed with fermentation material 10, the salt concentration of fermentation aid 3 will gradually increase, which will cause fermentation inhibition due to high salt content, and there is a risk that stable fermentation drying efficiency cannot be maintained in the batch-type aerobic fermentation treatment of waste 1.

[0056] Therefore, by desalting the fermented and dried granules 23 by washing them with water and then using them as a fermentation aid 3 mixed with the waste 1, it becomes possible to maintain the state where "chlorine concentration of waste 1 / (1 - reduction rate)" ≥ "chlorine concentration of fermentation aid 3". In the fermentation drying process of the fermentation material 10 to which the desalted fermented and dried granules 23 have been added as a fermentation aid 3, salt concentration and accumulation do not occur in the fermented and dried product 20 obtained by fermenting and drying the fermentation material 10, and stable fermentation drying efficiency can be maintained in the batch-type aerobic fermentation process of waste 1.

[0057] In particular, in this embodiment, as described above, the water used to spray the fermentation material 10 is collected together with the wastewater contained in the waste 1, and after foreign matter is removed by a filter, it is stored in a tank and reused for spraying, thus circulating the water. Since its salt concentration is in equilibrium with the salt concentration of the fermentation material 10, and because the spraying water does not easily penetrate into the interior of the accumulated fermentation material 10, the salt concentration of the fermentation material 10 does not easily dissolve into the spraying water, making it difficult to sufficiently remove inorganic chloride salts. Therefore, if the fermented and dried granules 23 are used as a fermentation aid 3 without desalting, the fermented and dried product 20 obtained by fermenting and drying the fermentation material 10 containing the fermentation aid 3 and waste 1 will have a higher salt concentration than the waste 1. If a portion of the fermented and dried product 20, which has a higher salt concentration than the waste 1, is repeatedly used as a fermentation aid 3, the salt concentration of the newly processed fermentation material 10 will be higher than that of the previously processed fermentation material 10. As a result, salt will be concentrated and accumulated in the fermentation material 10, and the salt concentration will gradually increase. When the salt concentration becomes high, fermentation inhibition will occur.

[0058] However, if the fermented and dried granules 23 are desalted by washing with water before being used as a fermentation aid 3 mixed with the waste 1, the salt concentration of the fermented and dried granules 23 used as a fermentation aid 3 is reduced by the desalting process. In particular, the amount of fermented and dried granules 23 is smaller than that of the waste 1 and the fermented and dried material 20, so inorganic chlorides can be removed from the fermented and dried granules 23 with a small amount of water. In this way, by mixing the fermented and dried granules 23, which have a lower salt concentration than the waste 1, with the waste 1 and fermenting and drying the waste 1, the concentration and accumulation of salts in the fermentation material 10 is prevented, and the salt concentration of the fermented and dried material 20 can be reduced.

[0059] Here, the chlorine content was measured for the fermented and dried granular material 23 before desalination treatment and the fermented and dried granular material 23 after desalination treatment (fermentation aid 3). The measurement results are shown in Table 1. In Table 1, the moisture content was measured by the loss on heating method, in which each sample was heated at 105°C for 3 hours, cooled in a desiccator, and then weighed. The chlorine content was measured by crushing each sample and using the measurement method specified in JIS Z 7302-6:1999 (Waste solidified fuel - Part 6: Total chlorine content test method 10.2 Cylinder mass method).

[0060] [Table 1]

[0061] As shown in Table 1, in sample A (normal product), the chlorine concentration before the desalination process (step S30) was high at 0.47%, but after the desalination process (step S30), the chlorine concentration was significantly reduced to 0.062%. Similarly, in sample B (high chlorine concentration product), the chlorine concentration before the desalination process (step S30) was high at 1.3%, but after the desalination process (step S30), the chlorine concentration was significantly reduced to 0.12%. In both samples, the amount of chlorine was reduced to about one-tenth after the desalination process (step S30).

[0062] Therefore, the salt concentration of the solid fuel raw material 210, which is selected from the fermented and dried product 20 and becomes the raw material for the production of solid fuel (RDF) 211, can be reduced, making it possible to expand its use to other applications. In other words, solid fuel (RDF) 211 with reduced salt concentration is not limited to use in waste incinerators equipped with power generation equipment (waste-to-energy generation), but becomes more versatile, and solid fuel (RDF) can be consumed even in areas that do not have waste incinerators equipped with power generation equipment (waste-to-energy generation) nearby, which will also lead to the spread of waste plants.

[0063] Thus, in this embodiment 1, the fermented dried granules 23 selected from the fermented dried product 20 are desalted by washing, and the amount of inorganic chlorine can be reduced by dissolving and removing the salts (salts) derived from inorganic chlorides such as sodium chloride contained in the waste 1 in water. As a result, the chlorine concentration of the fermented dried granules 23 selected from the fermented dried product 20 can be reduced to that of the waste 1. In batch-type fermented drying of waste 1, salt concentration and accumulation will not occur in the fermented dried product 20 obtained by fermenting and drying the fermentation material 10, which is made by mixing the fermentation aid 3 consisting of the desalted fermented dried granules 23 with the waste 1, and thus stable fermentation drying efficiency can be maintained in the waste treatment plant. In other words, by mixing the fermented dried granules 23, which have a lower chlorine concentration than waste 1, with waste 1 as a fermentation aid 3 and fermenting and drying it, the fermentation drying of waste 1 can be efficiently promoted, and stable fermentation drying efficiency can be maintained even in batch-type fermented drying of waste 1. Furthermore, by mixing fermented and dried granular material 23, which has a lower chlorine concentration than waste material 1, with waste material 1 as a fermentation aid 3 and fermenting and drying it, the chlorine concentration of the fermented and dried material 20 can also be reduced, and consequently, the salt concentration of the solid fuel raw material 210 selected from the fermented and dried material 20 can also be reduced. With solid fuel raw material 210 having a reduced chlorine concentration in this way, it is possible to reduce the chlorine concentration derived from inorganic chlorides in the solid fuel (RDF) 211 manufactured using that raw material to less than 1%, and to reduce the salt concentration to that of RPF, which is a solid fuel. Therefore, it becomes possible to provide a solid fuel (RDF) 211 that is highly versatile and does not degrade combustion equipment such as boilers.

[0064] In this embodiment 1, the desalting water washing treatment for the fermented dried granular material 23 selected from the fermented dried material 20 is performed by placing the fermented dried granular material 23 on a predetermined location such as a conveyor belt and spraying water over it. The water used in this water spraying treatment is separate from the wastewater (sewage) discharged from within the housing or building and collected, and has a lower salt concentration. Furthermore, in this embodiment 1, the water used for spraying the fermented dried granular material 23 is collected, dissolved inorganic chlorides are removed, and then it is recycled and reused again for spraying the fermented dried granular material 23.

[0065] In other words, in this embodiment 1, the water (excess water) sprayed onto the fermented dried granules 23 is recovered, and since the recovered water used to spray the fermented dried granules 23 contains dissolved inorganic chlorides derived from waste 1, these dissolved inorganic chlorides are removed. The water from which the inorganic chlorides have been removed is then filtered to remove foreign matter and reused in the desalination process (step S30) to spray onto the fermented dried granules 23 for desalination treatment. That is, the water sprayed onto the fermented dried granules 23 is recycled and reused for spraying after the inorganic chlorides have been removed. However, when implementing the present invention, the water from which the inorganic chlorides have been removed may be treated as sewage and discharged (drained to the outside) instead of being reused as spraying water and recycled. In this case, the water used for spraying the fermented dried granules 23 for desalination is either water recovered and purified from the spraying water of the biofilter or fresh water (water for use) brought in from the outside.

[0066] To remove inorganic chlorides dissolved in the water recovered after watering the fermented dried granular material 23, for example, a reverse osmosis method using a semipermeable membrane is used to separate the water containing dissolved inorganic chlorides into concentrated water and desalinated water from which the inorganic chlorides have been removed. The desalinated water from which the inorganic chlorides have been removed can be used again to water the fermented dried granular material 23. The concentrated water containing inorganic chlorides, separated from the desalinated water, is mixed with silver nitrate (aqueous solution) to produce a precipitate of silver chloride (insoluble salt), which is then removed by a filter or the like. Silver chloride is photodegraded by irradiation with ultraviolet light such as sunlight, releasing chlorine. The silver remaining after chlorine release is reacted with concentrated nitric acid to return it to silver nitrate, which is then used to repeatedly react with inorganic chlorides. In this way, it is possible to remove inorganic chlorides from the water recovered after watering the fermented dried granular material 23.

[0067] Furthermore, by performing a desalination treatment using water washing on the fermented dried granules 23, which are selected from the fermented dried material 20 and used as a fermentation aid 3 when aerobic fermentation of waste 1, the chlorine concentration of the solid fuel raw material 210 can be effectively reduced with low energy consumption as it does not require heating, and with a small amount of water used. Therefore, the salt concentration can be reduced effectively at low cost.

[0068] Thus, the waste treatment method and waste treatment plant of this embodiment 1 aerobically ferments waste 1, which contains a mixture of food waste, plastics, paper, cloth, etc., and dries it using the heat of fermentation and ventilation to produce fermented dried material 20. Solid fuel raw materials 210 are then selected from the fermented dried material 20 and recycled into solid fuel (RDF) 211.

[0069] In particular, in the waste treatment method and waste treatment plant of this embodiment 1, aerobic fermentation drying is promoted by mixing (returning) a portion of the fermented dried material 20, i.e., fermented dried fine particles 23 separated by particle size and weight from the fermented dried material 20, with the waste 1 to be aerobically fermented and dried as a fermentation aid 3, and then aerobic fermentation of the waste 1. The fermented dried fine particles 23 used as the fermentation aid 3 have their chlorine concentration reduced by a desalination treatment in which inorganic chlorides contained in the fermented dried fine particles 23 are dissolved in water by a water washing treatment after being separated from the fermented dried material 20. That is, in this embodiment 1, fermented dried fine particles 23 that have been separated from the fermented dried material 20 and whose chlorine concentration has been reduced by desalination are used as the fermentation aid 3. As a result, in batch-type fermentation and drying treatment of waste 1, even when waste 1 is mixed with a fermentation aid 3 and subjected to aerobic fermentation, salt concentration and accumulation do not occur in the fermentation material 10, and consequently in the fermented dried product 20. This prevents fermentation inhibition due to high salt content, maintains a stable aerobic fermentation capacity for waste 1, and keeps the salt concentration low in the fermentation material 10, which is a mixture of waste 1 and the fermentation aid 3, and in the fermented dried product 20 obtained by fermenting and drying it. Therefore, the salt concentration of the solid fuel raw material 210 selected from the fermented dried product 20 is low, making it possible to provide solid fuel (RDF) 211 with a low salt concentration.

[0070] In other words, the waste treatment method of this embodiment 1 comprises a fermentation drying step (step S10) in which waste 1 is aerobically fermented and dried to obtain a fermented dried product 20, a selection step (step S20) in which fermented dried granules 23 to be used as a fermentation aid 3 when aerobically fermenting waste 1 are selected from the fermented dried product 20, and a desalting step (step S30) in which the selected fermented dried granules 23, which are part of the fermented dried product 20, are desalted. In the fermentation drying step (step S10), the desalted fermented dried granules 23, which are part of the fermented dried product 20, are mixed with waste 1 as a fermentation aid 3 and the waste 1 is aerobically fermented.

[0071] Furthermore, the waste treatment plant of this embodiment 1 has a fermentation drying section, such as an aerobic fermentation drying apparatus equipped with watering means, ventilation means, etc., which aerobically ferments and dries the waste 1 to form a fermented dried product 20; sorting means, such as a particle size / weight sorter, which sorts fermented dried granules 23 used as a fermentation aid 3 when aerobically fermenting the waste 1 from the fermented dried product 20; and desalination means, such as watering means, which desalinates the sorted fermented dried granules 23, which are part of the fermented dried product 20. In the aerobic fermentation drying treatment of the waste 1, the fermentation aid 3, which is obtained by desalination of fermented dried granules 23, which are part of the fermented dried product 20, is mixed with the waste 1, and the waste 1 is aerobically fermented.

[0072] Thus, according to the waste treatment method and waste treatment plant of this embodiment 1, fermented dried granules 23, which have been separated from the fermented dried product 20 and desalted, are mixed with the waste 1 as a fermentation aid 3, and the waste 1 is subjected to aerobic fermentation. By washing the fermented dried granules 23 with water, inorganic chloride salts such as sodium chloride (NaCl) contained in the food residue, kitchen waste, etc., derived from the waste 1 are removed from the fermented dried granules 23, making it possible to reduce the salt concentration of the fermented dried granules 23 used as a fermentation aid 3 compared to the waste 1. Therefore, in the fermented dried product 20 obtained by fermenting and drying the waste 1 mixed with the fermentation aid 3, the situation in which salt is concentrated and accumulated and the salt concentration gradually increases is prevented, and the salt concentration of the fermented dried product 20 can be reduced. In other words, a portion of the fermented dried product 20 is mixed with untreated waste 1 as a fermentation aid 3 and aerobic fermentation is carried out. Alternatively, since the desalted fermentation aid 3 is mixed with the waste 1 and aerobic fermentation is carried out, in the batch-type aerobic fermentation treatment of waste 1, salt concentration and accumulation in the fermentation material 10 containing the fermentation aid 3 and waste 1, and consequently in the fermented dried product 20 obtained by fermenting and drying it, is prevented, and the salt concentration of the fermented dried product 20 can be reduced. Therefore, it is possible to reduce the concentration of chlorine derived from waste 1. Furthermore, when a portion of the fermented dried material 20 is recycled and used as a fermentation aid 3 during aerobic fermentation of untreated waste 1, the concentration and accumulation of salt in the fermentation material 10 containing the fermentation aid 3 and untreated waste 1, i.e., the inhibition of fermentation due to an increase in salt concentration, is prevented, thereby enabling stable fermentation drying efficiency of waste 1 over the long term.

[0073] As described above, the waste treatment method of Embodiment 1 comprises a fermentation drying step (step S10) in which waste 1 is aerobically fermented and dried to obtain a fermented dried product 20, and a desalting step (step S30) in which fermented dried fine particles 23, which are selected fermented dried products selected from the fermented dried product 20 and used as a fermentation aid 3 to be mixed with waste 1 when the waste 1 is aerobically fermented, are desalted. Specifically, the desalting step (step S30) involves desalting the fermented dried fine particles 23, which are selected from the fermented dried product 20 and mixed with waste 1 as a fermentation aid 3 when the waste 1 is aerobically fermented.

[0074] According to the waste treatment method of Embodiment 1 described above, in the fermentation drying step (step S10), the waste 1 is aerobically fermented and dried to obtain a fermented dried product 20, and in the desalting step (step S20), the fermented dried fine granules 23, which are selected fermented products separated from the fermented dried product 20, are desalted by washing with water, thereby removing the salt content of inorganic chlorides such as sodium chloride (NaCl) contained in food residues, kitchen waste, etc. derived from the waste 1 from the fermented dried fine granules 23. Therefore, by desalting the fermented dried granules 23 used as a fermentation aid 3 when aerobic fermenting waste 1 by washing them with water, the salt concentration of the fermented material 10, which includes the desalted fermentation aid 3 and waste 1, is reduced compared to when the unsalted fermentation aid 3 is used. As a result, even when a portion of the fermented dried material 20 is recycled and used in the aerobic fermentation cycle of waste 1, salt concentration and accumulation do not occur in the fermented material 10 during the process of aerobic fermentation drying of the fermented material 10, which includes a portion of the fermented dried material 20 and waste 1, and the salt concentration of the fermented dried material 20 obtained by fermenting and drying the fermented material 10 can be reduced. And by reducing the salt concentration of the fermented dried material 20, it becomes possible to form a solid fuel raw material 210 with a low salt concentration.

[0075] Thus, in the waste treatment method of Embodiment 1 described above, the selected fermented dried material to be desalted is the fermented dried fine granules 23 selected as a fermentation aid 3 to be mixed with the waste 1 when the waste 1 is aerobically fermented, and the desalting treatment of the selected fermented dried material is the desalting treatment of the fermented dried fine granules 23 selected as a fermentation aid 3 to be mixed with the waste 1 when the waste 1 is aerobically fermented. By making the fermented dried fine granules 23 used as a fermentation aid 3 low in salt concentration through desalting, even when the fermented dried fine granules 23, which is part of the fermented dried material 20, is circulated and used in the aerobic fermentation treatment cycle of the waste 1 as a fermentation aid 3, salt concentration and accumulation will not occur in the fermented material 10 during the process of aerobic fermentation drying of the fermented material 10 containing the fermentation aid 3 and the waste 1, and the salt concentration of the fermented dried material 20 obtained by fermenting and drying the fermented material 10 can be reduced.

[0076] Specifically, by desalting the fermented dried granules 23, which are part of the fermented dried product 20, and then using them as a fermentation aid 3 during the aerobic fermentation of the untreated waste 1, that is, by mixing the desalted fermented dried granules 23 with the untreated waste 1 as a fermentation aid 3 and carrying out aerobic fermentation, salt concentration and accumulation do not occur in the fermented material 10 during the process of aerobic fermentation drying of the fermented material 10 containing the fermentation aid 3 and waste 1, thereby reducing the salt concentration of the fermented dried product 20 obtained by fermenting and drying the fermented material 10. Consequently, the salt concentration of the solid fuel raw material 210 selected from the fermented dried product 20 is also reduced. Furthermore, by preventing fermentation inhibition due to salt concentration and accumulation in the batch-type aerobic fermentation process of the waste 1, a stable fermentation drying efficiency of the waste 1 is made possible over the long term.

[0077] Furthermore, according to the waste treatment method of Embodiment 1 described above, the desalination treatment is performed by washing with water the fermented and dried fine granules 23, which have been selected as a fermentation aid 3 to be mixed with the waste 1 during aerobic fermentation of the waste 1, as a selected fermented and dried product used as a fermentation aid 3. This method does not require heating and consumes little energy, and uses little water, while effectively reducing the chlorine concentration of the fermented and dried product 20, and consequently the solid fuel raw material 210. Therefore, the chlorine concentration of the solid fuel raw material 210 can be reduced at low cost.

[0078] In particular, in the desalination process, which involves washing the fermented dried granules 23, which are selected from the fermented dried product 20 and used as a fermentation aid 3 to be mixed with the waste 1 when the waste 1 is aerobically fermented, the washed fermented dried granules 23 are mixed with the untreated waste 1 in the next cycle when the waste 1 is aerobically fermented and dried by the fermentation drying of the waste 1. Therefore, there is no need to separately install heating equipment to remove the water used in the desalination process from the fermented dried granules 23, which are the selected fermented dried product, after the desalination process. Thus, the salt concentration derived from the waste 1 can be reduced at low cost without incurring equipment costs, and the chlorine concentration of the solid fuel raw material 210 selected from the fermented dried product 20 can be reduced. Consequently, it becomes possible to manufacture solid fuel (RDF) 211 with a low chlorine concentration.

[0079] Furthermore, the description of Embodiment 1 above can also be interpreted as an invention of a waste treatment plant comprising a fermentation and drying section for aerobic fermentation and drying of waste 1 to produce fermented dried product 20, and a desalination means for desalination of fermented dried fine granules 23, which are selected from the fermented dried product 20 and used as a fermentation aid 3 to be mixed with waste 1 when aerobic fermentation is performed on waste 1.

[0080] According to the waste treatment plant of Embodiment 1 described above, the waste 1 is aerobically fermented and dried in the fermentation drying section to obtain a fermented dried product 20, and the fermented dried fine granules 23, which are selected fermented products separated from the fermented dried product 20 by a desalting means, are desalted by washing with water, thereby removing the salt content of inorganic chlorides such as sodium chloride (NaCl) contained in food residues, kitchen waste, etc. derived from the waste 1 from the fermented dried fine granules 23. Therefore, by desalting the fermented dried granules 23 used as a fermentation aid 3 when aerobic fermenting waste 1 by washing them with water, the salt concentration of the fermented material 10, which includes the desalted fermentation aid 3 and waste 1, is reduced compared to when the unsalted fermentation aid 3 is used. As a result, even when a portion of the fermented dried material 20 is recycled and used in the aerobic fermentation cycle of waste 1, salt concentration and accumulation do not occur in the fermented material 10 during the process of aerobic fermentation drying of the fermented material 10, which includes a portion of the fermented dried material 20 and waste 1, and the salt concentration of the fermented dried material 20 obtained by fermenting and drying the fermented material 10 can be reduced. By reducing the salt concentration of the fermented dried material 20, it becomes possible to form a solid fuel raw material 210 with a low salt concentration.

[0081] Thus, in the waste plant of Embodiment 1 described above, the selected fermented and dried material to be desalted is the fermented and dried fine granules 23 selected as a fermentation aid 3 to be mixed with the waste 1 when the waste 1 is aerobically fermented, and the desalting treatment of the selected fermented and dried material is the desalting treatment of the fermented and dried fine granules 23 selected as a fermentation aid 3 to be mixed with the waste 1 when the waste 1 is aerobically fermented. By making the fermented and dried fine granules 23 used as a fermentation aid 3 low in salt concentration through desalting, even when the fermented and dried fine granules 23, which is part of the fermented and dried material 20, is circulated and used in the aerobic fermentation treatment cycle of the waste 1 as a fermentation aid 3, salt concentration and accumulation will not occur in the fermented material 10 during the process of aerobic fermentation drying of the fermented material 10 containing the fermentation aid 3 and the waste 1, and the salt concentration of the fermented and dried material 20 obtained by fermenting and drying the fermented material 10 can be reduced.

[0082] Specifically, by desalting the fermented dried granules 23, which are part of the fermented dried product 20, and then using them as a fermentation aid 3 during the aerobic fermentation of the untreated waste 1, that is, by mixing the desalted fermented dried granules 23 with the untreated waste 1 as a fermentation aid 3 and carrying out aerobic fermentation, salt concentration and accumulation do not occur in the fermented material 10 during the process of aerobic fermentation drying of the fermented material 10 containing the fermentation aid 3 and waste 1, thereby reducing the salt concentration of the fermented dried product 20 obtained by fermenting and drying the fermented material 10. Consequently, the salt concentration of the solid fuel raw material 210 selected from the fermented dried product 20 is also reduced. Furthermore, by preventing fermentation inhibition due to salt concentration and accumulation in the batch-type aerobic fermentation process of the waste 1, a stable fermentation drying efficiency of the waste 1 is made possible over the long term.

[0083] Furthermore, according to the waste treatment plant of Embodiment 1 described above, the desalination means is performed by washing with water the fermented and dried fine granules 23, which have been selected as a fermentation aid 3 to be mixed with the waste 1 during aerobic fermentation of the waste 1, as a selected fermented and dried product used as a fermentation aid 3. This method effectively reduces the chlorine concentration of the fermented and dried product 20, and consequently the solid fuel raw material 210, with low energy consumption as it does not require heating and with a small amount of water used. Therefore, the chlorine concentration of the solid fuel raw material 210 can be reduced at low cost.

[0084] Furthermore, according to the waste treatment method and waste treatment plant of Embodiment 1 described above, there is a vinyl chloride separation and removal step in which vinyl chloride is separated and removed from the fermented dried lightweight material 22, which is separated from the fermented dried material 20 to be used as the solid fuel raw material 211, by optical separation means such as near-infrared spectroscopy. This makes it possible to further reduce the chlorine concentration of the solid fuel raw material 211.

[0085] [Embodiment 2] Next, the overall general flow of waste treatment in the waste treatment plant and waste treatment method of Embodiment 2 of the present invention will be described with reference to Figures 3 and 4. The waste treatment of Embodiment 2 is applied to waste recycling, which involves recycling waste 1 into solid fuel (RDF) 211, pyrolysis oil (produced oil) 220, etc.

[0086] In the above embodiment 1, when fermented dried granules 23 selected from fermented dried product 20 obtained by aerobic fermentation and drying of fermented material 10 containing waste 1 are returned and reused as a fermentation aid 3 for aerobic fermentation of untreated waste 1, the fermented dried granules 23 are subjected to a desalination treatment by spraying water on them to remove inorganic chlorides contained in the fermented dried granules 23, and then mixed with waste 1 as a fermentation aid 3 for use.

[0087] In other words, in the above embodiment 1, a desalination process (step S30) is provided before the fermented dried granules 23, which are predetermined undersized lightweight materials selected from the fermented dried granules 20 obtained by aerobic fermentation and drying of the fermented material 10 in a sorting process (step S20) for particle size and weight sorting, are returned to the fermentation drying process (step S10) to be used as a fermentation aid 3 when aerobic fermentation of the untreated waste 1. There, a desalination process is performed in which water is sprayed onto the fermented dried granules 23 to remove inorganic chlorides contained in the fermented dried granules 23. This prevents the gradual concentration of salt in the fermented material 10, and by extension the fermented dried granules 20 obtained by fermenting and drying it, when a portion of the fermented dried granules 20 is mixed with the waste 1 as a fermentation aid 3 and subjected to aerobic fermentation, thereby enabling a reduction in the salt concentration of the fermented dried granules 20, which can also be used as a solid fuel raw material 210.

[0088] In contrast, in this second embodiment, a desalination treatment is performed on fermented dried lightweight material 22, which is selected from the fermented dried material 20 and mainly contains decomposed materials such as paper, plastics, and food waste, and is a predetermined oversized lightweight material that serves as a raw material for the production of solid fuel (RDF) 211 and pyrolysis oil (produced oil) 220. In this second embodiment, the chlorine derived from waste 1 is reduced by desalination treatment of the fermented dried lightweight material 22, which is selected from the fermented dried material 20 and serves as a raw material for the production of solid fuel (RDF) 211 and pyrolysis oil (derived oil) 220. Except for the difference in the target of desalination, this is the same as in the first embodiment described above, so detailed explanations that would be redundant are omitted here, and only the differences are explained.

[0089] The waste treatment method of this second embodiment includes a fermentation and drying step (step S10) in which waste 1 is aerobically fermented and dried to produce a fermented and dried product 20, a sorting step (step S20) in which raw materials for solid fuel (RDF) 211 and pyrolysis oil (produced oil) 220 are sorted from the fermented and dried product 20, and a desalination step (step S30) in which the sorted fermented and dried lightweight product 22 is desalined. Furthermore, the waste treatment plant of this second embodiment includes a fermentation drying section, such as an aerobic fermentation drying apparatus equipped with watering means, ventilation means, etc., which aerobically ferments and dries the waste 1 to form a fermented dried product 20; sorting means, such as a particle size / weight sorter, which sorts the fermented dried lightweight material 22 that will become solid fuel (RDF) 211 or pyrolysis oil (produced oil) 220 from the fermented dried product 20; and desalination means, such as watering means and heating means, which desalinate the sorted fermented dried lightweight material 22, which is part of the fermented dried product 20.

[0090] In other words, in this second embodiment, the fermented dried material 22, which is a predetermined oversized lightweight material that will be used as a raw material for producing solid fuel (RDF) 211 and pyrolysis oil (produced oil) 220, is separated from the fermented dried material 20 obtained by aerobic fermentation and drying of the fermented material 10 in a particle size and weight sorting sorting process (step S20). From this, metals 310 are sorted and removed by magnetic sorting (step S24), and if necessary, polyvinyl chloride 330 is sorted and removed by optical sorting (step S25). Then, a desalination process (step 130) is provided where the fermented dried lightweight material 22 is desalined.

[0091] In the desalination process (step 130) of this embodiment 2, first, a water washing treatment is performed to desalinate the fermented dried lightweight material 22A, from which the metals 310 and polyvinyl chloride 330 have been removed, by spraying water on it to dissolve the inorganic chlorides contained in the fermented dried lightweight material 22A in water (step S131). Next, the fermented and dried lightweight material 22A from which inorganic chlorides have been removed is heated at a predetermined temperature to perform a heat treatment that desalinates organochlorine compounds such as vinylidene chloride (PVDC), vinyl chloride (PVC), chlorinated polyvinyl chloride, and chlorinated rubber contained in the fermented and dried lightweight material 22A (step S132).

[0092] The desalination water washing treatment for the fermented dried lightweight material 22A, which has been separated from the fermented dried material 20 to remove metals 310 and polyvinyl chloride 330, is carried out in the same way as in Embodiment 1 above. For example, the fermented dried lightweight material 22A is placed on a predetermined location such as on a conveyor belt, and water is sprayed or misted onto the fermented dried lightweight material 22A from above. The water used in this water spraying treatment is different from the wastewater (sewage) discharged from inside the housing or building and recovered, and has a lower salt concentration. In Embodiment 2 as well, the water used for spraying the fermented dried lightweight material 22A is recovered, dissolved inorganic chlorides are removed, and then it is recycled and reused again for spraying the fermented dried lightweight material 22A.

[0093] In other words, in this second embodiment as well, the water (excess water) sprayed onto the fermented dried lightweight material 22A is recovered, and since the recovered water used to spray the fermented dried lightweight material 22A contains dissolved inorganic chlorides derived from waste 1, these dissolved inorganic chlorides are removed. The water from which the inorganic chlorides have been removed is then filtered to remove foreign matter, and then recycled and reused in the desalination process (step S130) to spray the fermented dried lightweight material 22A for desalination treatment. However, when implementing the present invention, the water from which the inorganic chlorides have been removed may be treated as sewage and discharged (drained to the outside) instead of being reused or recycled as spray water. In this case, the water used to spray the fermented dried lightweight material 22A for desalination may be water recovered and purified from the spray water of the biofilter or fresh water from the outside (water supply).

[0094] Similar to Embodiment 1 described above, in order to remove the inorganic chlorides dissolved in the water recovered after being used to spray the fermented dried lightweight material 22A, for example, the water containing dissolved inorganic chlorides is separated into concentrated inorganic chloride water and desalinated water from which the inorganic chlorides have been removed using a reverse osmosis membrane method with a semipermeable membrane. The desalinated water from which the inorganic chlorides have been removed can be used again to spray the fermented dried lightweight material 22A. The concentrated inorganic chloride water separated from the desalinated water is mixed with silver nitrate (aqueous solution) to produce a precipitate of silver chloride (insoluble salt), which is then removed by a filter or the like. Silver chloride is photodegraded by irradiation with ultraviolet light such as sunlight, releasing chlorine. The silver remaining after chlorine release is reacted with concentrated nitric acid to return it to silver nitrate, which is then used to repeatedly react with inorganic chlorides. In this way, it is possible to remove inorganic chlorides from the water recovered after being used to spray the fermented dried lightweight material 22A.

[0095] The fermented and dried lightweight material 22A, from which inorganic chlorides have been removed, is further subjected to a desalination treatment by thermally decomposing and desalting the organochlorine compounds contained in the fermented and dried lightweight material 22A by heat treatment at a predetermined high temperature. A continuous or batch type desalination apparatus is used for the desalination and oxidation treatment. By heating the fermented and dried lightweight material 22A after washing at a temperature of 250°C or higher and 300°C or lower, chlorine and hydrogen are removed from organochlorine compounds such as vinylidene chloride (PVDC) and vinyl chloride (PVC), resulting in desalination and oxidation, and the chlorine content of the organochlorine compounds is removed.

[0096] The desalination apparatus D1 mainly comprises, for example, as shown in Figure 4, a desalination heating section that heats the fermented and dried lightweight material 22A after washing at 250°C or higher and 300°C or lower using an electric heater or burner, a cooling condenser that cools the steam generated by heating the fermented and dried lightweight material 22A, a hydrochloric acid recovery tank that stores the liquid hydrogen chloride (hydrochloric acid) generated by cooling by the cooling condenser, a hydrogen chloride trap that absorbs the hydrogen chloride gas that has passed through the cooling condenser, and an off-gas treatment device.

[0097] The fermented and dried lightweight material 22A is placed in a hopper and heated in a desalination heating section at a temperature between 250°C and 300°C. This process removes chlorine and hydrogen from organochlorine compounds such as vinylidene chloride (PVDC) and polyvinyl chloride (PVC) contained in the fermented and dried lightweight material 22A, generating hydrogen chloride gas. The hydrogen chloride gas is discharged from the desalination heating section as steam containing hydrogen chloride gas. The discharged steam is cooled in a cooling condenser to become liquid hydrogen chloride (hydrochloric acid), which is then recovered in a hydrochloric acid recovery tank. After passing through the cooling condenser, the gas is removed by a hydrogen chloride trap that absorbs hydrogen chloride, and then incinerated (combusted) in an off-gas treatment device or used as fuel. The hydrochloric acid recovered in the hydrochloric acid recovery tank is usually available for use as an industrial chemical. In this second embodiment, chlorine and hydrogen are removed from the organochlorine compound by heating at 250°C or higher and 300°C or lower. That is, the chlorine concentration is reduced by dehydrochlorination, and the resulting fermented and dried lightweight residue 22A becomes the solid fuel raw material 210. Furthermore, the remaining organic chlorine compounds after the chlorine and hydrogen atoms have been removed are organic compounds or carbides that do not contain chlorine atoms.

[0098] Thus, in the waste treatment method and waste treatment plant of this embodiment 2, the fermented dried lightweight material 22A, which has been separated from the fermented dried material 20 and from which metals 310 and polyvinyl chloride 330 have been removed, is subjected to a water washing treatment to remove inorganic chlorides from the fermented dried lightweight material 22A. Furthermore, the fermented dried lightweight material 22A after the water washing treatment is heated at a temperature of 250°C or higher and 300°C or lower to desalinate and oxidize the organic chlorides in the fermented dried lightweight material 22A. This reduces the chlorine concentration of the fermented dried lightweight material 22A, resulting in a solid fuel raw material 210 with a low salt concentration.

[0099] In particular, the waste treatment method and waste treatment plant of this embodiment 2 can remove inorganic chloride salts such as sodium chloride (NaCl) contained in food residues, kitchen waste, etc., derived from the waste 1 of the fermented and dried lightweight material 22 used as solid fuel raw material 210, as well as organic chlorine compound salts such as vinylidene chloride (PVDC) and vinyl chloride (PVC) contained in food wrap, etc., derived from the waste 1. Therefore, the salt reduction effect can be enhanced.

[0100] Incidentally, in this second embodiment, the explanation described performing the desalination process for inorganic chlorides (step S131) ​​first, followed by the dehydrochlorination process for organochlorine compounds (step S132). However, when implementing the present invention, the dehydrochlorination process for organochlorine compounds may be performed first, followed by the desalination process for inorganic chlorine compounds. However, performing the desalination process for inorganic chlorides by washing with water before the dehydrochlorination process for organochlorine compounds by heat treatment results in a higher salt removal rate for inorganic chlorides and reduces the amount of residual inorganic chlorides. This is because, in the fermented and dried lightweight material 22A that has been subjected to high-temperature heat treatment of 250-300°C, the inorganic chlorides are trapped in the thermoset resin or carbonized resin and are difficult to dissolve in water. Furthermore, if the fermented and dried lightweight material 22A, which has undergone the dehydrochlorination process for organochlorine compounds first and then the dehydrochlorination treatment for inorganic chlorine compounds by water spraying, is used as a solid fuel raw material 210, it is necessary to provide ancillary equipment for heating and drying to remove the water added by water spraying, which will consume extra energy for heating and drying. From the perspective of saving energy consumption and reducing costs, it is preferable to perform a desalination step of inorganic chlorides by washing with water before the dechlorination step of organochlorine compounds that are subjected to heat treatment.

[0101] Furthermore, in Embodiment 2 of the above description, the fermented and dried lightweight residue 22A, from which chlorine and hydrogen in the organochlorine compound are removed by heating at 250°C or higher and 300°C or lower, i.e., the chlorine concentration is reduced by dehydrochlorination, is used as the solid fuel raw material 210. However, when implementing the present invention, it is also possible to further heat the fermented and dried lightweight residue 22A, which has been heated at 250°C or higher and 300°C or lower, to a temperature exceeding 300°C and 700°C or lower to thermally decompose the hydrocarbon components of the fermented and dried lightweight residue 22A and produce pyrolysis oil (produced oil) 220. That is, pyrolysis oil (produced oil) 220 is produced from the fermented and dried lightweight residue 22, and the oiled residue may be used as a modified solid fuel raw material 210A to produce solid fuel (RDF).

[0102] When performing oil conversion by thermal decomposition of the hydrocarbon component of the fermented and dried lightweight material 22A, as shown in Figure 4, the desalination and thermal decomposition apparatus D2 includes a desalination heating section that heats the material at 250°C or higher and 300°C or lower using an electric heater or burner, a cooling condenser that cools the steam generated by heating the fermented and dried lightweight material 22A at 250°C or higher and 300°C or lower, a hydrochloric acid recovery tank that stores the liquid hydrogen chloride (hydrochloric acid) generated by cooling by the cooling condenser, and a hydrogen chloride trap that absorbs the hydrogen chloride gas that has passed through the cooling condenser. In addition to including an off-gas treatment device, the system includes a decomposition heating section located downstream of a desalination heating section that heats the desalination-dried lightweight material 22A to a temperature between 300°C and 700°C, a cooling condenser for cooling the gas generated by heating the desalination-dried lightweight material 22A to a temperature between 300°C and 700°C in the decomposition heating section, an oil-water separator for separating the liquid oil and water cooled by the cooling condenser, and an oil tank for recovering the pyrolysis oil (produced oil) 220, which is the oil component separated by the oil-water separator. Furthermore, a separation device may be provided to separate the pyrolysis oil (produced oil) 220 into light oil, medium oil, and heavy oil, and the light oil separated from the pyrolysis oil (produced oil) 220 may be used as machine fuel, the medium oil as boiler fuel, and the heavy oil as power generation. Furthermore, the gas that passes through the cooling condenser is incinerated (burned) in an off-gas treatment device, or used as fuel.

[0103] In this desalination and pyrolysis apparatus D2, the fermented and dried lightweight material 22A is fed into a hopper, and in the desalination heating section, chlorine and hydrogen are removed from the organochlorine compounds by heating at 250°C to 300°C, i.e., the chlorine concentration of the fermented and dried lightweight material 22A is reduced by dehydrochlorination. The remaining fermented and dried lightweight material 22A is then heated in the decomposition heating section to over 300°C and below 700°C, causing the hydrocarbon components in the fermented and dried lightweight material 22A to be pyrolyzed (converted into oil). The gas discharged from the decomposition heating section due to the pyrolysis of hydrocarbon components is cooled in a cooling condenser to become oil-water, and the oily product (pyrolysis oil) 220 is separated by an oil-water separator and recovered in an oil tank. The recovered product (pyrolysis oil) 220 can be used as fuel for machinery and boilers, for power generation, etc. Then, the residue of the fermented and dried lightweight material 22A, which has been heated to over 300°C and below 700°C in the decomposition heating section, is recovered as modified solid fuel raw material 210B and converted into solid fuel (RDF).

[0104] In the desalination and pyrolysis unit D2, as described above, the fermented and dried lightweight material 22A is heated at 250°C or higher and 300°C or lower in the desalination heating section, causing chlorine and hydrogen to be removed from organochlorine compounds such as vinylidene chloride (PVDC) and vinyl chloride (PVC), generating hydrogen chloride gas. The hydrogen chloride gas is discharged from the desalination heating section as steam containing hydrogen chloride gas, and the discharged steam is cooled in a cooling condenser to become liquid hydrogen chloride (hydrochloric acid), which is then recovered in a hydrochloric acid recovery tank. After passing through the cooling condenser, the gas is removed in a hydrogen chloride trap that absorbs hydrogen chloride, and then, together with the off-gas from which oil and water have been separated, it is incinerated (combusted) in an off-gas treatment device or used as fuel. When heated to 250°C or higher and 300°C or lower, the chlorine and hydrogen of the organochlorine compounds are removed, leaving behind organic compounds and chars that do not contain chlorine atoms. The fermented and dried lightweight residue 22A, which is the desalted and oxidized residue, has had its hydrogen content removed, so even when heated to over 300°C and 700°C or lower for thermal decomposition, it produces little tar, which can clog pipes or inhibit gasification.

[0105] In particular, the pyrolysis oil 220 produced by liquefaction has a density of approximately 0.7 to 0.9, which is equivalent to heavy oil. Compared to solid fuel (RDF) 211, which has a density of approximately 0.3 to 0.4, it is denser and, being liquid, easier to control combustion than solid fuel (RDF) 221. Therefore, it has a wide range of applications, and high consumption and demand are expected near waste disposal plants.

[0106] As described above, the waste treatment method of Embodiment 2 comprises a fermentation and drying step (step S10) in which waste 1 is aerobically fermented and dried to produce fermented dried product 20, and a desalination step (step S130) in which fermented dried lightweight product 22, which is selected from the fermented dried product 20 and becomes a raw material for solid fuel (RDF) 211 and pyrolysis oil 220, is subjected to desalination treatment.

[0107] According to the waste treatment method of Embodiment 2 described above, in the fermentation drying process (step S10), waste 1 is aerobically fermented and dried to obtain fermented dried product 20. In the desalination process (step S130), fermented dried lightweight product 22, which is selected from the fermented dried product 20 to be used as raw material for solid fuel (RDF) 211 and pyrolysis oil 220, is subjected to desalination treatment by washing with water and heating at a predetermined temperature. This treatment removes the salt content of inorganic chlorides such as sodium chloride (NaCl) and organic chlorine compounds such as vinylidene chloride (PVDC) and vinyl chloride (PVC) contained in food residues, kitchen waste, etc., derived from waste 1. Therefore, the desalined fermented dried lightweight product 22 becomes a solid fuel raw material 210, 210A with a low salt concentration.

[0108] Thus, in the waste treatment method of Embodiment 2 described above, the selected fermented dried material to be desalted is the fermented dried lightweight material 22 selected from the fermented dried material 20 as a raw material for solid fuel (RDF) 211 or pyrolysis oil 220, and the desalting treatment of the selected fermented dried material is the desalting treatment of the fermented dried lightweight material 22 selected as a raw material for solid fuel (RDF) 210 or pyrolysis oil 220. By washing the fermented dried lightweight material 22 selected from the fermented dried material 20 for use as a raw material for solid fuel (RDF) 210 or pyrolysis oil 220 with water and desalting by heating at a predetermined temperature, the salt concentration of the solid fuel raw materials 210 and 210A, which are raw materials for the production of solid fuel (RDF) 210, can be reduced.

[0109] Furthermore, according to the waste treatment method of Embodiment 2 described above, the desalination treatment is carried out by washing the fermented dried lightweight material 22A, which has been separated from the fermented dried material 20 to be used as raw material for solid fuel (RDF) 210 and pyrolysis oil 220, and from which metals 310 and vinyl chloride 330 have been removed, with water and heating in the range of 250°C or higher and 300°C or lower. This can remove the salt content of inorganic chlorides such as sodium chloride (NaCl) and organic chlorine compounds such as vinylidene chloride (PVDC) and vinyl chloride (PVC) contained in the food residue, kitchen waste, etc. of the waste 1, so the salt content reduction effect of the waste 1 is high and the salt content can be sufficiently removed, making it possible to produce solid fuel raw materials 210 and 210A with a lower chlorine concentration.

[0110] In addition, in the above embodiment 2, if a pyrolysis step is further performed, where the material is heated to a temperature above 300°C and below 700°C after the desalination treatment at a temperature of 250-300°C or below, pyrolysis oil 220 can be produced by the pyrolysis of the hydrocarbon components of the desalination-dried lightweight material 22. Therefore, it becomes possible to broaden its uses as a chemically recycled product. In particular, since the pyrolysis oil 220 thus produced is denser and more liquid than solid fuel (RDF) 211, combustion control is easier than with solid fuel (RDF) 211, making it highly versatile and suitable for a wide range of uses, and high consumption and demand can be expected near waste disposal plants.

[0111] Furthermore, the description of Embodiment 2 above can also be interpreted as an invention of a waste treatment plant comprising a fermentation and drying section that aerobically ferments and dries waste 1 to produce fermented dried product 20, and a desalination means that desalinates fermented dried lightweight product 22, which is selected from the fermented dried product 20 and serves as a raw material for solid fuel (RDF) 211 and pyrolysis oil 220.

[0112] According to the waste treatment plant of Embodiment 2 described above, waste 1 is aerobically fermented and dried in the fermentation drying section to obtain fermented dried product 20. The fermented dried lightweight product 22, which is selected from the fermented dried product 20 as a raw material for solid fuel (RDF) 211 and pyrolysis oil 220, is desalted by a water washing treatment using a desalting means. This treatment removes the salts of inorganic chlorides such as sodium chloride (NaCl) and organic chlorine compounds such as vinylidene chloride (PVDC) and vinyl chloride (PVC) contained in food residues, kitchen waste, etc. derived from waste 1. Therefore, the fermented dried lightweight product 22 selected from the fermented dried product 20 and desalted becomes a solid fuel raw material 210, 210A with a low salt concentration.

[0113] Thus, in the waste plant of Embodiment 2 described above, the selected fermented dried material to be desalted is the fermented dried lightweight material 22 selected from the fermented dried material 20 as a raw material for solid fuel (RDF) 211 and pyrolysis oil 220, and the desalting treatment of the selected fermented dried material is the desalting treatment of the fermented dried lightweight material 22 selected as a raw material for solid fuel (RDF) 210 and pyrolysis oil 220. By washing the fermented dried lightweight material 22 selected from the fermented dried material 20 for use as a raw material for solid fuel (RDF) 210 and pyrolysis oil 220 with water and desalting treatment by heating at a predetermined temperature, the salt concentration of the solid fuel raw materials 210 and 210A, which are raw materials for the production of solid fuel (RDF) 210, can be reduced.

[0114] Furthermore, according to the waste treatment plant of Embodiment 2 described above, the desalination treatment is carried out by washing the fermented dried lightweight material 22A, which has been separated from the fermented dried material 20 to be used as raw material for solid fuel (RDF) 210 and pyrolysis oil 220, and from which metals 310 and vinyl chloride 330 have been removed, with water and heating in the range of 250°C or higher and 300°C or lower. This treatment can remove the salt content of inorganic chlorides such as sodium chloride (NaCl) and organic chlorine compounds such as vinylidene chloride (PVDC) and vinyl chloride (PVC) contained in the food residue, kitchen waste, etc. of the waste 1, so the salt content of the waste 1 is reduced and the salt content can be sufficiently removed, making it possible to produce solid fuel raw materials 210 and 210A with a lower chlorine concentration.

[0115] In addition, in the above embodiment 2, if a thermal decomposition means is provided that further heats the material to a temperature above 300°C and below 700°C after the heat treatment at 250-300°C or below as a desalination treatment, the hydrocarbon components of the desalinized fermented dried lightweight material 22 can be thermally decomposed to produce thermal decomposition oil 220. Therefore, it becomes possible to broaden the uses of the product as a chemical recycled product. In particular, since the thermal decomposition oil 220 thus produced is denser and more liquid than solid fuel (RDF) 211, combustion control is easier than with solid fuel (RDF) 211, making it highly versatile and suitable for a wide range of uses, and high consumption and demand can be expected near waste disposal plants.

[0116] Incidentally, in the above embodiment 2, the fermented dried lightweight material 22, which is a selected fermented product that will be used as a raw material for solid fuel (RDF) 211 and pyrolysis oil 220 selected from the fermented dried product 20, was described as being desalted by washing with water and heating at a predetermined temperature. However, when implementing the present invention, inorganic chlorides may be removed by washing with water alone, or organic chlorides may be removed by heating at a predetermined temperature alone. Even these single treatments alone can reduce the chlorine concentration derived from the waste 1.

[0117] Furthermore, in Embodiment 2 described above, similar to Embodiment 1, the fermented dried granules 23 selected from the fermented dried product 20 may be desalted before being used as the fermentation aid 3. This makes it possible to further reduce the concentration of chlorine derived from the waste 1. In the above embodiment 2, in order to desalt the fermented dried lightweight material 22 selected from the fermented dried material 20, the step of separating and removing polyvinyl chloride 330 by optical separation (step S25) (polyvinyl chloride separation step) may be omitted. Alternatively, after separating and removing metals 310 from the fermented dried lightweight material 22 by magnetic separation (step S24), the desalting step (step 130) may be carried out without the optical separation step. This reduces the number of steps.

[0118] [Embodiment 3] Next, the waste treatment method and the overall flow of waste treatment in the waste treatment plant according to Embodiment 3 of the present invention will be described with reference to Figure 5. The waste treatment in Embodiment 3 is also applied to waste recycling, which involves recycling waste 1 into solid fuel (RDF) 211, etc.

[0119] As described in Embodiment 1 above, in the fermentation drying process (step S10) in which the fermentation material 10 is fermented and dried, water is sprayed onto the fermentation material 10 within the housing of the aerobic fermentation drying apparatus, which serves as the fermentation drying section. The water contained in the waste 1 and the excess water sprayed are collected, foreign matter is removed with a filter, and then the water is reused for spraying, thereby circulating the sprayed water. By spraying water onto the fermentation material 10, the moisture activates fermentation by aerobic microorganisms. Furthermore, the circulation of this water causes the aerobic microorganisms to move from top to bottom across the fermentation material 10, thus enabling efficient fermentation by uniformly distributing the aerobic microorganisms across the fermentation material 10.

[0120] Incidentally, in the fermentation process of waste 1 by microorganisms in this fermentation and drying process (step S10), bacteria, filamentous fungi, etc., actively decompose easily decomposable organic substances in waste 1, such as proteins, amino acids, and sugars, during the first few days, raising the temperature of waste 1 and, consequently, the inside of the housing. Once the easily decomposable substances are consumed and the temperature rises, thermophilic aerobic actinomycetes, etc., become involved in the decomposition of organic matter, and the decomposition of hemicellulose and cellulose begins, with the temperature reaching a maximum of 60°C to 80°C. This high-temperature environment kills various bacteria, thus ensuring the hygiene of the processed material. Pathogenic bacteria are usually sterilized at 55°C or higher for 3 days, preferably 65°C or higher for 48 hours or more. Subsequently, a medium temperature range of 30°C to 50°C is maintained to further promote the decomposition of organic matter. After that, the amount of air taken in from outside the housing is increased to promote cooling and drying.

[0121] Here, wastewater (leachate) seeping from the fermentation material 10 containing waste 1, which is undergoing aerobic fermentation, and excess water from the spraying are collected. After filtering out any foreign matter contained therein, the water is sprayed back onto the fermentation material 10 as spray water. Thus, the spray water is recycled and reused. However, considering the hygiene of the recycled spray water, the amount of water sprayed is limited after the sanitization process, which involves killing bacteria in a high-temperature environment. In particular, the water used for watering is not discharged to the outside, but is repeatedly used within the waste plant to water new untreated fermented materials 10 for aerobic fermentation treatment. Therefore, the salinity of the water used for spraying is in equilibrium with the chloride concentration in the fermentation material 10, and remains stable.

[0122] Therefore, in this embodiment 3, in the process of killing bacteria in a high-temperature environment, new water (water for irrigation) with a lower salt concentration than the water that had been circulated and used for irrigation is introduced, and this new water is used for irrigation. This desalinates the fermentation material 10 containing the waste 1 during fermentation. In other words, in this embodiment 3, a desalination process (step S230) is carried out during the fermentation of the waste 1. As a result, water with a lower salt concentration than the water that was circulated before the process of killing bacteria in a high-temperature environment, mainly the salt concentration derived from inorganic chlorides leached from the waste 1 of the fermentation material 10, is sprayed onto the fermentation material 10, thereby allowing further inorganic chloride salts to be leached from the fermentation material 10. Therefore, the fermented dried product 20 obtained by drying the fermentation material 10 with reduced salt concentration will have a low salt concentration. And because the fermented dried product 20 can have a low salt concentration, the salt concentration of the solid fuel raw material 210, which is selected from the fermented dried product 20 and becomes the raw material for manufacturing solid fuel 210, will also be low, and the solid fuel 210 manufactured from it will also have a low salt concentration.

[0123] Thus, in this third embodiment, desalination is performed during aerobic fermentation of waste 1. Since this is the same as in the first and second embodiments described above, except for the object of desalination, we will omit redundant detailed explanations here and only explain the differences.

[0124] As explained using the diagram inserted in the flowchart of Figure 5, in the waste plant of this embodiment 3, in the fermentation drying process (step S10), there is a watering circulation path W1 used for watering the fermentation material 10, including the waste 1 accumulated in the housing, from the initial stage of aerobic fermentation until it reaches a high temperature environment of 50°C, and an introduction path I for introducing water from the outside, which is used for watering from the high temperature environment exceeding 50°C until it cools and dries. There is also a watering circulation path W2 that supplies water with a lower salinity than the water supplied to the fermentation material 10 from the watering circulation path W1, thus providing two watering circulation paths with different salinity levels.

[0125] During the initial stages of aerobic fermentation of the fermentation material 10 containing waste 1, until the temperature reaches 50°C, there is no external water supply, and the water is repeatedly circulated and used for spraying, resulting in high-salinity water being used to spray the fermentation material 10 via the spraying circulation path W1. During the initial stages of aerobic fermentation of the fermentation material 10, until the temperature reaches 50°C, the water collected from the bottom of the housing is filtered by filter f1 to remove foreign matter, stored in tank T1, and then circulated again as spray water. Once the temperature exceeds 50°C and the process of killing bacteria begins, the water supply from the spraying circulation path W1 is stopped, and new external water with a lower salinity than the water supplied from the spraying circulation path W1 is supplied (replenished) from the introduction path I and used to spray the fermentation material 10 via circulation path W2. As a result, inorganic chlorides in the waste 1 of the fermentation material 10 dissolve into the spray water, desalting it. The water newly sprayed in the circulation path W2 is also recovered and used for repeated spraying after passing through the filter f2 and tank T2.

[0126] Furthermore, the water circulated in circulation path W1 or circulation path W2 may be used to spray water onto the untreated fermented material 10 in the next cycle after removing inorganic chlorides. To remove inorganic chlorides dissolved in water used for watering and recovered, for example, a reverse osmosis method using a semipermeable membrane is used to separate the water containing dissolved inorganic chlorides into concentrated water and desalinated water from which the inorganic chlorides have been removed. The desalinated water from which the inorganic chlorides have been removed can be used again for watering the fermentation material 10. The concentrated water containing inorganic chlorides, separated from the desalinated water, is mixed with silver nitrate (aqueous solution) to produce a precipitate of silver chloride (insoluble salt), which is then removed by a filter or the like. Silver chloride is photodegraded by irradiation with ultraviolet light such as sunlight, releasing chlorine. The silver remaining after chlorine release is reacted with concentrated nitric acid to return it to silver nitrate, which is then used to repeatedly react with inorganic chlorides. In this way, it is possible to remove inorganic chlorides from the water used for watering the fermentation material 1 and recovered.

[0127] In particular, in this embodiment 3, watering is carried out even after the sanitizing process of aerobic fermentation of the fermentation material 10, which promotes the progress of fermentation and stabilizes the fermentation material 10. Therefore, the resulting solid fuel raw material 210 and solid fuel (RDF) 211 are prevented from undergoing re-fermentation (secondary fermentation) due to humidity and temperature, resulting in a safer and more stable product that is less likely to produce unpleasant odors and gases due to re-fermentation.

[0128] As described above, the waste treatment method of Embodiment 3 comprises a fermentation and drying step (step S10) in which waste 1 is aerobically fermented and dried to produce a fermented dried product 20, and a desalination step (step S230) in which waste 1 undergoes aerobic fermentation to desalinate.

[0129] Therefore, according to the waste treatment method of Embodiment 3 described above, in the fermentation drying step (step S10) in which waste 1 is aerobically fermented and dried to produce a fermented dried product 20, a desalination step (step S230) is performed to desalinate the waste 1 during aerobic fermentation, thereby producing a fermented dried product 20 with a reduced salt concentration. Thus, a solid fuel raw material 210 with a low salt concentration can be provided.

[0130] Thus, the waste treatment method of Embodiment 3 described above is a desalination treatment of the waste 1 during fermentation. By reducing the salt concentration of the waste 1 during fermentation through the desalination treatment, the salt concentration of the fermented dried product 20 obtained by drying it is also reduced. As a result, the salt concentration of the fermented dried product 20, which becomes the raw material for solid fuel 210, is reduced, thereby reducing the salt concentration of the solid fuel 211.

[0131] Furthermore, according to the waste treatment method of Embodiment 3 described above, the desalination treatment is carried out by washing the waste 1 during fermentation with water, and since the salt content of inorganic chlorides such as sodium chloride (NaCl) contained in food residues, kitchen waste, etc. in the waste 1 is removed, the chlorine content of the waste 1 can be reduced at low cost.

[0132] Furthermore, the description of Embodiment 3 above can also be interpreted as an invention of a waste treatment plant comprising a fermentation and drying section that aerobically ferments and dries waste 1 to produce a fermented and dried product 20, and a desalination means for desalinizing waste 1 during aerobically fermented processes.

[0133] Therefore, according to the waste treatment plant of Embodiment 3 described above, by desalting the waste 1 undergoing aerobic fermentation using a desalting means, a fermented dried product 20 with reduced salt concentration can be produced. This makes it possible to provide a solid fuel raw material 210 with a low salt concentration. In other words, it is a desalting treatment of the waste 1 undergoing fermentation, and by reducing the salt concentration of the waste 1 undergoing fermentation through the desalting treatment, the salt concentration of the fermented dried product 20 obtained by drying it is also reduced. As a result, the salt concentration of the fermented dried product 20 that becomes the solid fuel raw material 210 is reduced, and thus the salt concentration of the solid fuel 211 can be reduced.

[0134] Furthermore, according to the waste treatment plant of Embodiment 3 described above, the desalination treatment is carried out by washing the waste 1 during fermentation with water, and since it removes the salt content of inorganic chlorides such as sodium chloride (NaCl) contained in food residues, kitchen waste, etc. in the waste 1, the chlorine content of the waste 1 can be reduced at low cost.

[0135] In the above embodiment 3, similar to embodiment 1, the fermented dried fine granules 23 selected from the fermented dried product 20 may be desalted before being used as the fermentation aid 3. Also, similar to embodiment 2, the fermented dried lightweight material 22 selected from the fermented dried product 20 may be desalted and used as a raw material for the production of solid fuel (RDF) 211 or pyrolysis oil (produced oil) 220. This makes it possible to further reduce the concentration of chlorine derived from the waste 1.

[0136] When implementing the present invention, the desalination process of Embodiment 1 (step S30), the desalination process of Embodiment 2 (step S130), and the desalination process of Embodiment 3 (step S130) may be implemented individually, or any two or more may be implemented in combination. That is, in addition to the desalination process of Embodiment 1 (step S30), the desalination process of Embodiment 2 (step S130) and / or the desalination process of Embodiment 3 (step S130) may be implemented, or the desalination process of Embodiment 2 (step S130) and the desalination process of Embodiment 3 (step S130) may be implemented.

[0137] According to the waste treatment methods and waste plants of Embodiments 1 to 3 described above, inorganic chlorides derived from food waste and chlorine derived from chlorine-containing plastics in waste 1 can be removed, making it possible to form solid fuel (RDF) with a chlorine concentration as low as that of solid fuel (RPF).

[0138] By the way, in the descriptions of Embodiments 1 to 3 above, the fermented dried granules 23 selected from the fermented dried product 20 were described as being used as a fermentation aid 3. However, when implementing the present invention, a portion of the fermented dried granules 23 may be used as compost raw material 230. The compost raw material 230 can be matured in a separate maturation bed for several days to several weeks while being watered and aerated, similar to the aerobic fermentation drying described above. After that, it can be sieved according to its intended use and usage conditions, and further matured if necessary to produce high-quality compost.

[0139] The waste treatment method of Embodiment 1 described above involves aerobic fermentation and drying of the waste in a fermentation drying step to obtain a fermented dried product, and then desalting the selected fermented dried product, which is selected from the fermented dried product and used as a fermentation aid to be mixed with the waste during aerobic fermentation of the waste, in a desalting step.

[0140] The above fermentation and drying process involves aerobic fermentation of waste materials in an airtight housing that allows for the introduction and discharge of air from the outside and controls the pressure to prevent odor leakage, thereby removing moisture and drying the waste using the heat generated by the fermentation. Preferably, the aerobic fermentation and drying of the waste are promoted by supplying air to the waste. In addition, uniform aerobic fermentation is promoted by spraying water on the waste during fermentation. In particular, in this fermentation and drying process, a portion of the desalted fermented and dried material, i.e., selected fermented and dried material that has been separated from the fermented and dried material and desalted, is mixed with the waste as a fermentation aid to efficiently aerobic fermentation and drying of the waste.

[0141] The above desalination process removes salts derived from waste. The selected fermented dried material, which is separated from the fermented dried material and used as a fermentation aid mixed with the waste during aerobic fermentation, is subjected to a desalination process, such as washing with water, to dissolve and remove inorganic chloride salts such as sodium chloride (NaCl), calcium chloride (CaCl2), and magnesium chloride (MgCl2) contained in food waste (food residue) and other waste-derived materials.

[0142] The above-mentioned waste includes household general waste such as food waste and paper scraps that can be burned, as well as office waste and organic waste such as food waste and animal residues as industrial waste.

[0143] The desalination treatment in the waste treatment method of Embodiment 1 described above involves washing the sorted fermented and dried material used as a fermentation aid with water to dissolve inorganic chloride salts such as sodium chloride derived from the waste in water and desalinate it. The above-mentioned washing treatment can be any treatment that dissolves water-soluble salts (soluble salts) of inorganic chlorides such as sodium chloride derived from waste. For example, this can be done by spraying water, water misting, or steam treatment on the sorted fermented and dried material used as a fermentation aid, or by immersion treatment such as stirring or bubbling in a water tank with the fermentation aid.

[0144] The waste treatment method of Embodiment 3 described above involves a fermentation and drying process in which the waste is aerobically fermented and dried to obtain a fermented and dried product, and a desalting process in which the waste is desalted while fermentation is in progress.

[0145] The above fermentation and drying process involves aerobic fermentation of waste materials in an airtight housing that allows for the introduction and discharge of air from the outside and controls the pressure to prevent odor leakage, thereby removing moisture and drying the waste using the heat generated by the fermentation. Preferably, the aerobic fermentation and drying of the waste are promoted by supplying air to the waste. Preferably, a portion of the fermented and dried material is mixed with the waste as a fermentation aid, and more preferably, a desalted fermentation aid is mixed with the waste to efficiently aerobic fermentation and drying of the waste. In particular, this fermentation and drying process also includes a desalination process, for example, in which the waste is desalted by spraying water onto it during fermentation.

[0146] The above desalination process removes salts derived from waste. For example, by spraying water onto the waste during fermentation, inorganic chloride salts such as sodium chloride (NaCl), calcium chloride (CaCl2), and magnesium chloride (MgCl2) contained in food waste (raw materials) are dissolved in water and removed.

[0147] In the fermentation drying step of the waste treatment method of Embodiment 3 described above, the waste is subjected to a watering treatment while it is fermenting, and the desalination treatment is performed by spraying the waste with water having a lower salinity than the water sprayed on it from the initial stage of fermentation until the waste reaches 50°C due to fermentation, after the waste exceeds 50°C. In the process of killing bacteria in a high-temperature environment, desalination is performed by replacing the water sprayed with water having a lower salinity than the water sprayed before the high-temperature environment.

[0148] The waste treatment plant of Embodiment 1 described above comprises a fermentation and drying section that aerobically ferments and dries the waste to obtain a fermented and dried product, and a desalting means for desalting selected fermented and dried products that are selected from the fermented and dried product and used as a fermentation aid to be mixed with the waste when the waste is aerobically fermented.

[0149] The above-mentioned fermentation and drying unit can be any unit that aerobically ferments waste and dries it using the heat of fermentation. For example, it is composed of an aerobic fermentation and drying apparatus equipped with an airtight housing that allows for the introduction and discharge of air from the outside by a fan (blower), etc., and controls the air pressure with negative pressure to prevent odor leakage. Preferably, it is equipped with a blower that supplies air to the waste, and air is blown onto the waste placed in the housing to promote the progress of aerobic fermentation and drying of the waste. In addition, a means for spraying water on the waste during fermentation is provided to promote uniform aerobic fermentation of the waste. In particular, in this aerobic fermentation and drying, a portion of the desalted fermented and dried material, that is, a selected fermented and dried material that has been separated from the fermented and dried material and desalted, is mixed with the waste as a fermentation aid, and the waste is efficiently aerobically fermented and dried.

[0150] The above desalination method removes salts derived from waste. It removes inorganic chloride salts such as sodium chloride (NaCl), calcium chloride (CaCl2), and magnesium chloride (MgCl2) contained in food waste (food scraps, etc.) by dissolving them in water through a desalination process, which involves washing the selected fermented dried material, which is separated from the fermented dried material and used as a fermentation aid to be mixed with the waste during aerobic fermentation.

[0151] The desalination means of the waste treatment plant in Embodiment 1 described above desalinates by dissolving inorganic chloride salts such as sodium chloride derived from the waste in water through a water washing treatment of the sorted fermented and dried material used as a fermentation aid. The above-mentioned washing treatment can be any treatment that dissolves water-soluble salts (soluble salts) of inorganic chlorides such as sodium chloride derived from waste. For example, this can be done by spraying water, water misting, or steam treatment on the sorted fermented and dried material used as a fermentation aid, or by immersion treatment such as stirring or bubbling in a water tank with the fermentation aid.

[0152] The waste treatment plant of the above embodiment 3 comprises a fermentation and drying section that aerobically ferments and dries the waste to produce a fermented and dried product, and a desalination means for desalting the waste during fermentation.

[0153] The above-mentioned fermentation and drying unit can be any unit that aerobically ferments waste and dries it using the heat of fermentation. For example, it is composed of an aerobic fermentation and drying apparatus equipped with an airtight housing that allows for the introduction and discharge of air from the outside by a fan (blower), etc., and controls the pressure to a negative level to prevent odor leakage. Preferably, it is equipped with a blower that supplies air to the waste, and air is blown onto the waste placed in the housing to promote the progress of aerobic fermentation and drying of the waste. Preferably, it is equipped with a watering means for spraying water on the waste during fermentation to promote uniform aerobic fermentation of the waste. Furthermore, preferably, a portion of the fermented and dried material is mixed with the waste as a fermentation aid, and more preferably, a desalted fermentation aid is mixed with the waste to efficiently aerobic ferment and dry the waste. In particular, in this aerobic fermentation and drying, for example, the waste is desalted by a desalting means such as spraying water on the waste during fermentation.

[0154] The above desalination method removes salts derived from waste. For example, by washing the waste during fermentation, inorganic chloride salts such as sodium chloride (NaCl), calcium chloride (CaCl2), and magnesium chloride (MgCl2) contained in food waste (food scraps) are dissolved in water and removed.

[0155] The desalination means of the waste treatment plant in Embodiment 3 described above involves spraying water with a lower salinity than the water sprayed on the waste from the initial stage of fermentation until the waste reaches 50°C due to fermentation, after the waste exceeds 50°C. In the process of killing bacteria in a high-temperature environment, desalination is achieved by replacing the water sprayed with water with a lower salinity than the water sprayed before the high-temperature environment.

[0156] According to the waste treatment method of Embodiment 1 described above, in the fermentation drying process, the waste is aerobically fermented and dried to obtain a fermented dried product, and in the desalting process, the selected fermented dried product, which is separated from the fermented dried product and used as a fermentation aid to be mixed with the waste during aerobic fermentation of the waste, is desalted to remove waste-derived salts from the selected fermented dried product. In particular, the desalting treatment of the selected fermented dried product by washing it with water can remove inorganic chloride salts such as sodium chloride (NaCl) contained in food residues, kitchen waste, etc. Therefore, it is possible to reduce the salt concentration of the fermented dried product obtained by mixing the desalted selected fermented dried product with the waste as a fermentation aid and fermenting and drying it. In other words, while a portion of the fermented and dried material is mixed with the untreated waste for the next cycle as a fermentation aid, the fermented and dried waste is mixed with a desalted fermentation aid. Therefore, in batch-type waste fermentation and drying, salt concentration and accumulation in the fermentation materials containing the fermentation aid and waste, and consequently in the fermented and dried material obtained by fermenting and drying them, is prevented. Thus, it is possible to reduce the salt concentration of the fermented and dried material, and to reduce the chlorine concentration of the solid fuel raw material selected from the fermented and dried material. In this way, the concentration of chlorine derived from the waste is reduced.

[0157] Furthermore, even when the selected fermented and dried material, separated from the fermented and dried material, is recycled and used as a fermentation aid when untreated waste is aerobically fermented, the desalted fermentation aid is mixed with the waste and aerobic fermentation is carried out. This prevents salt concentration and accumulation in the fermentation material containing the fermentation aid and untreated waste, thereby preventing fermentation inhibition due to increased salt concentration. As a result, the waste fermentation and drying capacity does not decrease, and a stable waste fermentation and drying efficiency is maintained over the long term.

[0158] According to the waste treatment method of Embodiment 1 described above, the desalination treatment is carried out by washing the sorted fermented and dried material used as the fermentation aid with water. This desalination treatment requires little energy consumption as it does not require heating and uses little water, and can reduce the salt concentration of the fermented and dried material, thus enabling a reduction in the concentration of chlorine derived from waste at a low cost.

[0159] According to the waste treatment method of Embodiment 3 described above, in the fermentation drying process, the waste is aerobically fermented and dried to obtain a fermented dried product, and in the desalination process, the waste is desalinized during fermentation to remove salts derived from the waste. In particular, the desalination treatment by washing the waste during fermentation can remove inorganic chloride salts such as sodium chloride (NaCl) contained in food residues, kitchen waste, etc. Therefore, the fermented dried product obtained by drying the fermented and desalinized waste has a low salt concentration, and the solid fuel raw material selected from the fermented dried product also has a low salt concentration. In this way, it is possible to reduce the concentration of chlorine derived from the waste.

[0160] According to the waste treatment method of Embodiment 3 described above, in the fermentation drying step, the waste is treated with water while fermentation is in progress, and in the desalination step, water with a lower salinity than the water used to spray the waste from the initial stage of fermentation until the waste reaches 50°C due to fermentation is sprayed on the waste after the waste exceeds 50°C to perform desalination. Therefore, since the desalination process does not require heating and consumes little energy, the salinity of the fermented and dried material can be reduced, making it possible to reduce the concentration of chlorine derived from the waste at a low cost.

[0161] According to the waste treatment plant of Embodiment 1 described above, waste is aerobically fermented and dried in the fermentation drying section to obtain a fermented dried product, and the selected fermented dried product, which is separated from the fermented dried product by the desalting means and used as a fermentation aid to be mixed with the waste during aerobic fermentation, is desalted to remove waste-derived salts from the selected fermented dried product. In particular, the desalting treatment of the selected fermented dried product by washing it with water can remove inorganic chloride salts such as sodium chloride (NaCl) contained in food residues, kitchen waste, etc. Therefore, it is possible to reduce the salt concentration of the fermented dried product obtained by mixing the desalted selected fermented dried product with waste as a fermentation aid and fermenting and drying it. In other words, while a portion of the fermented and dried material is mixed with the untreated waste for the next cycle as a fermentation aid, the fermented and dried waste is mixed with a desalted fermentation aid. Therefore, in batch-type waste fermentation and drying, salt concentration and accumulation in the fermentation materials containing the fermentation aid and waste, and consequently in the fermented and dried material obtained by fermenting and drying them, is prevented. Thus, it is possible to reduce the salt concentration of the fermented and dried material, and to reduce the chlorine concentration of the solid fuel raw material selected from the fermented and dried material. In this way, the concentration of chlorine derived from the waste is reduced.

[0162] Furthermore, even when the selected fermented and dried material, separated from the fermented and dried material, is recycled and used as a fermentation aid when untreated waste is aerobically fermented, the desalted fermentation aid is mixed with the waste and aerobic fermentation is carried out. This prevents salt concentration and accumulation in the fermentation material containing the fermentation aid and untreated waste, thereby preventing fermentation inhibition due to increased salt concentration. As a result, the waste fermentation and drying capacity does not decrease, and a stable waste fermentation and drying efficiency is maintained over the long term.

[0163] According to the waste treatment plant of Embodiment 1 described above, the desalination means is performed by washing the sorted fermented and dried material used as a fermentation aid with water. This desalination process does not require heating, consumes little energy, and uses little water, thereby reducing the chlorine concentration of the fermented and dried material. This makes it possible to reduce the concentration of chlorine derived from waste at a low cost.

[0164] According to the waste treatment plant of Embodiment 3 described above, waste is aerobically fermented and dried in the fermentation drying section to obtain a fermented dried product, and salts derived from the waste are removed by desalting the waste during fermentation using the desalting means. In particular, desalting treatment by washing the waste during fermentation can remove inorganic chloride salts such as sodium chloride (NaCl) contained in food residues, kitchen waste, etc. Therefore, the fermented dried product obtained by drying the fermented and desalted waste has a low salt concentration, and the solid fuel raw material selected from the fermented dried product also has a low salt concentration. In this way, it is possible to reduce the concentration of chlorine derived from the waste.

[0165] According to the waste treatment plant of Embodiment 3 described above, the desalination means desalinates the waste by spraying it with water having a lower salinity than the water sprayed on the waste from the initial stage of fermentation until the waste reaches 50°C due to fermentation, after the waste exceeds 50°C. Therefore, since the desalination process does not require heating and consumes little energy, the salinity of the fermented and dried material can be reduced, making it possible to reduce the concentration of chlorine derived from the waste at a low cost.

[0166] It should be noted that while the above explanation of aerobic fermentation has been based on the premise of using aerobic microorganisms, this does not mean that there is absolutely no attachment of anaerobic microorganisms. Rather, it means that an environment is created in which aerobic microorganisms can function. Furthermore, when implementing the present invention, the configuration, components, formulation, manufacturing method, etc., of other parts of the waste treatment plant and waste treatment method are not limited to the above-described examples. Also, not all of the numerical values ​​given in the embodiments and examples of the present invention represent critical values; some numerical values ​​represent suitable values ​​for implementation. Therefore, slightly changing the above numerical values ​​within the permissible range does not negate implementation. [Explanation of Symbols]

[0167] 1. Waste 3. Fermentation aids 20 Fermented and dried products 22. Fermented and dried lightweight material (selected fermented and dried material) 23. Fermented and dried fine granules (selected fermented and dried product) 210,210A Solid fuel raw material 211 Solid fuel (RDF) 220 Pyrolysis oil (produced oil)

Claims

1. A fermentation and drying process in which waste is aerobically fermented and dried to produce a fermented and dried product, A desalination process is performed to desalinate the selected fermented dried product, which is selected from the fermented dried product and becomes a raw material for solid fuel. A waste disposal method characterized by comprising the following:

2. The waste treatment method according to claim 1, characterized in that the desalination treatment comprises washing the sorted fermented and dried material that will be used as a raw material for the solid fuel with water and heating it at a temperature of 250°C or higher and 300°C or lower.

3. Furthermore, the waste treatment method according to claim 2 is characterized by comprising a thermal decomposition step of heating at a temperature exceeding 300°C but not exceeding 700°C after the aforementioned heat treatment at a temperature of 250°C or higher and 300°C or lower.

4. A fermentation and drying processing unit that aerobically ferments and dries waste to produce a fermented and dried product, A desalting means for desalting selected fermented dried material, which is selected from the aforementioned fermented dried material and used as a raw material for solid fuel, A waste treatment plant characterized by being equipped with the following.

5. The waste treatment plant according to claim 4, characterized in that the desalination means is a water washing treatment of the sorted fermented and dried material that will be used as a raw material for the solid fuel and a heat treatment at 250°C or higher and 300°C or lower.

6. Furthermore, the waste treatment plant according to claim 5 is characterized by comprising a thermal decomposition means for heating to a temperature above 300°C and below 700°C after the aforementioned heat treatment at a temperature of 250°C or higher and below 300°C.

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