Waste treatment system and waste treatment method

Abstract

To provide a waste disposal system that can produce methane from resin-containing waste, which contains a resin component, while reducing the amount of methane production through syngas.SOLUTION: The present invention discloses a system for disposing of resin-containing waste, which contains a resin component. The system includes: a resin component degrading part 2 that has a degradation tank 3 to be fed with the resin-containing waste and heats the resin-containing waste in the presence of an amine compound to hydrolyze at least part of the resin component into monomers; and a methane fermenting part 4 that has a fermentation tank 5 to be fed with organic waste containing refractory solid and the monomers from the resin component degrading part, and subjects the organic waste and the monomers to methane fermentation.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a system and method for treating resin-containing waste containing a resin component. [Background technology]

[0002] Development of recycling technologies for waste plastics has been underway for many years, and currently established methods include material recycling, in which waste plastics are recycled as raw materials for plastic products; chemical recycling, in which waste plastics are recycled into gases that can be used as chemical raw materials or fuel; and thermal recycling, in which waste plastics are burned to recover energy.

[0003] Incidentally, for waste containing a single resin component such as polyethylene terephthalate (PET) as waste plastic, it is easy to subject the waste to material recycling to recover raw materials for plastic products. However, for waste containing various resin components as waste plastic, it is difficult to recover raw materials for plastic products through material recycling.

[0004] Therefore, when recycling waste containing various resin components as waste plastics, techniques such as the above-mentioned chemical recycling and thermal recycling are used.

[0005] For example, Patent Document 1 proposes a method for recycling waste materials including plastics by chemical recycling. In the method described in Patent Document 1, waste materials including plastics are gasified at low temperatures, and the resulting gaseous material and a carbonized solid material called char are gasified at high temperatures to obtain gas that can be used as a chemical raw material or fuel. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-128288 Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, when producing methane from waste plastics using chemical recycling, syngas (a mixed gas mainly containing hydrogen and carbon monoxide) is first produced from the waste plastics, and the carbon monoxide in this syngas is then methanated. However, when producing syngas from waste plastics, the waste plastics are decomposed at the molecular level, and for example, there may be a shortage of hydrogen required to methanate all of the carbon monoxide in the obtained syngas, making it necessary to produce hydrogen separately.

[0008] At a time when a decarbonized society is desired, hydrogen is a relatively expensive energy source, so methane produced using large amounts of it is inevitably expensive, resulting in increased recycling costs.

[0009] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a waste treatment system and a waste treatment method that can produce methane from resin-containing waste that contains resin components while reducing the amount of methane produced via syngas. [Means for solving the problem]

[0010] The waste treatment system according to the present invention for achieving the above object has the following features: A system for treating resin-containing waste containing a resin component, comprising: a resin component decomposition section having a decomposition tank to which the resin-containing waste is supplied, and heating the resin-containing waste in the presence of an amine compound to hydrolyze at least a part of the resin components into monomers; a methane fermentation section that has a fermenter to which organic waste containing a hard-to-decompose solid content and the monomer obtained in the resin component decomposition section are supplied, and that performs methane fermentation of the organic waste and the monomer. 、 The resin-containing waste is such that the amount of the resin component that can be decomposed in the resin component decomposition section is adjusted so that the amount of the monomer that can be obtained in the resin component decomposition section is equal to or less than the amount that can be supplied to the fermenter, which is determined according to a remaining volume load obtained by subtracting the volume load of the organic waste supplied to the fermenter from the total volume load of the fermenter, The methane fermentation unit is configured to perform methane fermentation of the organic waste in a state where the volume load of the organic waste to the fermentation tank is 5 g CODcr / L / day or less when the monomer is not supplied to the fermentation tank. It is at the point.

[0011] The waste treatment method according to the present invention for achieving the above object is characterized by the following features: A method for treating resin-containing waste containing a resin component, comprising the steps of: a resin component decomposition step of supplying the resin-containing waste to a decomposition tank and heating the resin-containing waste in the presence of an amine compound to hydrolyze at least a portion of the resin component into a monomer; A methane fermentation step is carried out by supplying organic waste containing a hard-to-decompose solid content and the monomer obtained in the resin component decomposition step to a fermenter and subjecting the organic waste and the monomer to methane fermentation. stomach, The resin-containing waste is such that the amount of the resin component that can be decomposed in the resin component decomposition step is adjusted so that the amount of the monomer that can be decomposed in the resin component decomposition step is equal to or less than the amount that can be supplied to the fermenter, which is determined according to a remaining volume load obtained by subtracting the volume load of the organic waste supplied to the fermenter from the total volume load of the fermenter, The methane fermentation step is configured to perform methane fermentation of the organic waste in a state where the volume load of the organic waste to the fermentation tank is 5 g CODcr / L / day or less in a state where the monomer is not supplied to the fermentation tank. It is at the point.

[0012] In methane fermentation of organic waste containing difficult-to-decompose solids such as sewage sludge, the difficult-to-decompose solids are solubilized to water-soluble organic matter, which is then converted to organic acid by acid fermentation, and methane is produced from the organic acid. Here, the solubilization of difficult-to-decompose solids proceeds slowly, so methane fermentation is difficult for organic waste containing difficult-to-decompose solids. For this reason, when only organic waste containing difficult-to-decompose solids, rather than easily decomposable solids such as food waste, is subjected to methane fermentation in a fermenter, the volume load on the fermenter cannot be increased, resulting in a low volume load and ineffective use of the fermenter. However, according to the above-mentioned characteristic configuration, a part of the resin component in the resin-containing waste can be decomposed into a monomer. Unlike organic waste containing a refractory solid content, this monomer does not require solubilization, and therefore methane fermentation proceeds more easily than organic waste containing a refractory solid content. Therefore, by supplying a monomer to a fermenter in which methane fermentation of organic waste containing a refractory solid content is being performed, it is possible to achieve both methane fermentation of organic waste containing a refractory solid content (production of methane through a solubilization stage of the refractory solid content and an acid fermentation stage of water-soluble organic matter) and methane fermentation of monomers (production of methane through an acid fermentation stage when the monomer is an organic matter, and production of methane based on the organic acid when the monomer is an organic acid) in the fermenter, and it is possible to efficiently produce methane from organic waste and monomers by effectively utilizing the methane fermentation section, which has a low volume load on the fermenter when only organic waste is fermented. In this manner, according to the above-mentioned characteristic configuration, methane can be obtained by methane fermentation of monomers obtained by decomposing a part of the resin components in the resin-containing waste using a facility for methane fermentation of organic waste, that is, methane can be produced from at least a part of the resin components in the resin-containing waste without going through syngas. Therefore, according to the above-mentioned characteristic configuration, methane can be produced from the resin-containing waste while reducing the amount of methane produced through syngas. Furthermore, according to the above-mentioned characteristic configuration, it is also possible to suppress an increase in the cost required for recycling the resin-containing waste. In addition, by decomposing the resin components in the resin-containing waste, it is possible to obtain monomers in an amount equivalent to the above-mentioned supplyable amount, and the obtained monomers can be supplied to the fermenter. Therefore, according to the above-mentioned characteristic configuration, it is possible to supply an appropriate amount of monomers according to the remaining volume load to the fermenter. Furthermore, a methane fermentation section in which the volumetric load of organic waste to the fermenter is 5 g CODcr / L / day or less, i.e., a methane fermentation section in which the volumetric load is low and the fermenter is not effectively utilized when performing methane fermentation of organic waste, can be used to decompose a portion of the resin components in the resin-containing waste, and the resulting monomers can be fermented to obtain methane.

[0017] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The present invention is characterized in that it is provided with an undecomposed component gasification section which thermally decomposes the resin components in the resin-containing waste supplied to the decomposition tank that have not been decomposed in the resin component decomposition section, thereby generating gas containing at least hydrogen and carbon monoxide.

[0018] According to the above characteristic configuration, gas containing components such as hydrogen and carbon monoxide that can be used as chemical raw materials or fuel gas can be produced from the resin components that were not decomposed in the resin component decomposition section.

[0019] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The present invention is characterized in that at least the hydrogen generated in the undecomposed component gasification section is supplied to the fermentation tank.

[0020] When methanogens are present in the fermenter, it is possible to produce methane from carbon dioxide generated by methane fermentation by supplying hydrogen into the fermenter. That is, according to the above-mentioned characteristic configuration, it is possible for the methanogens to produce methane under conditions in which the methanogens are present in the fermenter.

[0021] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The gas generating apparatus has a production tank to which at least the carbon monoxide out of the gas produced in the undecomposed component gasification section is supplied, and further includes an acetic acid production section for producing acetic acid from the carbon monoxide.

[0022] According to the above-mentioned characteristic configuration, it is possible to produce acetic acid, which can be used as a substrate for methane fermentation, a chemical raw material, or the like, based on the carbon monoxide produced in the undecomposed component gasification section.

[0023] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The resin-containing waste is The amount of the resin component that can be decomposed in the resin component decomposition unit is adjusted so that the monomer can be obtained in the resin component decomposition unit in an amount equivalent to the amount that can be supplied to the fermenter, which is determined according to a remaining volume load obtained by subtracting the volume load of the organic waste supplied to the fermenter from the total volume load of the fermenter; The amount of the resin components that is not decomposed in the resin component decomposition section is adjusted so that the amount of hydrogen required for methanation of carbon dioxide generated by methane fermentation of the organic waste and the monomer in the methane fermentation section is produced in the undecomposed component gasification section.

[0024] According to the above characteristic configuration, the resin components in the resin-containing waste are decomposed, so that monomers of the same amount as the above supplyable amount can be obtained, and the obtained monomers can be supplied to the fermenter. Furthermore, the resin components that are not decomposed in the resin component decomposition section are gasified in the undecomposed component gasification section, so that the amount of hydrogen required for methanation of carbon dioxide generated in the methane fermentation section can be obtained, and the obtained hydrogen can be supplied to the fermenter. In other words, according to the above characteristic configuration, an appropriate amount of monomers according to the remaining volume load in the fermenter can be supplied to the fermenter, and an appropriate amount of hydrogen according to the amount of carbon dioxide generated in the fermenter can be supplied to the fermenter.

[0025] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The methane fermentation unit is configured to be able to perform solid-liquid separation processing, The present invention is characterized in that the solid content obtained by the solid-liquid separation treatment in the methane fermentation section is supplied to the undecomposed component gasification section.

[0026] According to the above characteristic configuration, the solid fraction obtained by the solid-liquid separation process in the methane fermentation section is gasified in the undecomposed component gasification section, and a gas containing components that can be used as chemical raw materials or fuel gas can be obtained.

[0027] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The heat generated by burning the carbon monoxide produced in the undecomposed component gasification section is utilized in the resin component decomposition section or the methane fermentation section.

[0028] The hydrolysis treatment of the resin components in the resin component decomposition section is carried out at about 55 to 220° C., and the methane fermentation of the organic waste and monomers in the methane fermentation section is carried out at about 20 to 60° C. According to the above-mentioned characteristic configuration, the heat required for the hydrolysis treatment in the resin component decomposition section and the methane fermentation in the methane fermentation section can be compensated for by the heat generated by the combustion of carbon monoxide.

[0029] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The present invention is characterized in that it includes an undecomposed component combustion section that combusts the resin components that are not decomposed in the resin component decomposition section out of the resin components in the resin-containing waste supplied to the decomposition tank.

[0030] According to the above-mentioned characteristic configuration, the resin components that have not been decomposed in the resin component decomposition section can be combusted to obtain heat.

[0031] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The heat generated in the undecomposed component combustion section is utilized in the resin component decomposition section or the methane fermentation section.

[0032] The hydrolysis treatment of the resin components in the resin component decomposition section is carried out at about 55 to 220° C., and the methane fermentation of the organic waste and monomers in the methane fermentation section is carried out at about 20 to 60° C. According to the above-mentioned characteristic configuration, the heat required for the hydrolysis treatment in the resin component decomposition section and the methane fermentation in the methane fermentation section can be compensated for by the heat generated in the undecomposed component combustion section.

[0033] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The methane fermentation unit is configured to be able to perform solid-liquid separation processing, The methane fermentation section is configured to supply the solid content obtained by the solid-liquid separation process to the undecomposed component combustion section.

[0034] According to the above-mentioned characteristic configuration, the solid content obtained by the solid-liquid separation process in the methane fermentation section is combusted in the undecomposed component combustion section, thereby making it possible to obtain heat.

[0035] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The resin component decomposition section is configured to recover and reuse the water vapor and the amine compound generated in the decomposition tank.

[0036] The amine compound used in the resin component decomposition section functions as a catalyst for hydrolyzing the resin components. According to the above-mentioned characteristic configuration, the water vapor and the amine compound remaining in the decomposition tank after the resin components are hydrolyzed can be recovered and reused.

[0037] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The resin component contains a resin having at least an ester bond site, The resin component decomposition section decomposes the resin having the ester bond site into each of the constituent components as the monomer.

[0038] According to the above-mentioned characteristic configuration, in the resin component decomposition section, at least the ester bond site of the resin having an ester bond site can be hydrolyzed to obtain a monomer.

[0039] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The resin component contains at least polyester, The resin component decomposition section decomposes the polyester into each of the constituent components as the monomers.

[0040] According to the above-mentioned characteristic configuration, the ester bond site of the polyester can be hydrolyzed in the resin component decomposition section to obtain a monomer.

[0041] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The resin component contains at least a resin derived from biomass, The resin component decomposition section decomposes the biomass-derived resin into each of the constituent components as the monomers.

[0042] As a result of extensive research, the inventors of the present application have found that biomass-derived resins are easily decomposed in the resin component decomposition section. That is, according to the above-mentioned characteristic configuration, methane can be efficiently produced from resin-containing waste that contains, as a resin component, a biomass-derived resin that is easily decomposed in the resin component decomposition section.

[0043] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The resin component includes a resin having lactic acid or 3-hydroxybutyric acid as a monomer component, The resin component decomposition section decomposes a resin having lactic acid or 3-hydroxybutyric acid as the monomer component into the lactic acid or 3-hydroxybutyric acid as the monomer.

[0044] As a result of extensive research, the inventors of the present application have found that a resin having lactic acid or 3-hydroxybutyric acid as a monomer component is easily decomposed in the resin component decomposition section. That is, according to the above-mentioned characteristic configuration, methane can be efficiently produced from resin-containing waste containing, as a resin component, a resin having lactic acid or 3-hydroxybutyric acid as a monomer component that is easily decomposed in the resin component decomposition section.

[0045] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The resin component contains at least polylactic acid, The resin component decomposition section decomposes the polylactic acid into lactic acid as the monomer.

[0046] As a result of extensive research, the inventors of the present application have found that polylactic acid is particularly susceptible to decomposition in the resin component decomposition section. In other words, according to the above-mentioned characteristic configuration, methane can be efficiently produced from resin-containing waste that contains polylactic acid, which is particularly susceptible to decomposition, as a resin component.

[0047] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The resin component contains at least polyhydroxyalkanoate, The resin component decomposition section decomposes the polyhydroxyalkanoate into each of the constituent components as the monomer.

[0048] As a result of extensive research, the inventors of the present application have found that polyhydroxyalkanoates are particularly susceptible to decomposition in the resin component decomposition section. That is, according to the above-mentioned characteristic configuration, methane can be efficiently produced from resin-containing waste that contains polyhydroxyalkanoates, which are particularly susceptible to decomposition, as a resin component.

[0049] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The resin component contains at least poly(3-hydroxybutyric acid), The resin component decomposition section decomposes the poly(3-hydroxybutyric acid) into the monomer, 3-hydroxybutyric acid.

[0050] As a result of intensive research, the inventors of the present application have found that poly(3-hydroxybutyric acid), which is one of polyhydroxyalkanoates, is easily decomposed in the resin component decomposition section. That is, according to the above-mentioned characteristic configuration, methane can be efficiently produced from resin-containing waste that contains poly(3-hydroxybutyric acid), which is particularly easily decomposed, as a resin component.

[0051] Further characteristic configurations of the waste treatment system according to the present invention are as follows: The organic waste is sewage sludge.

[0052] According to the above characteristic configuration, the facility can be used for methane fermentation of sewage sludge, which is organic waste containing difficult-to-decompose solids, to produce methane from the sewage sludge and monomers derived from resin-containing waste. [Brief description of the drawings]

[0053] [Figure 1] 1 is a diagram showing a schematic configuration of a waste treatment system according to a first embodiment. [Diagram 2] FIG. 11 is a diagram showing a schematic configuration of a waste treatment system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] First Embodiment DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A waste treatment system and a waste treatment method according to a first embodiment of the present invention will now be described with reference to the drawings.

[0055] First, a waste treatment system 1 according to a first embodiment will be described. Fig. 1 is a diagram showing a schematic configuration of the waste treatment system 1. As shown in Fig. 1, the waste treatment system 1 is a system for treating resin-containing waste containing a resin component, and includes a decomposition tank 3 to which the resin-containing waste is supplied, a resin component decomposition device 2 (resin component decomposition section) that heats the resin-containing waste in the presence of an amine compound to hydrolyze at least a part of the resin components into monomers, and a methane fermentation device 4 (methane fermentation section) that has a fermentation tank 5 to which organic waste containing a hard-to-decompose solid content and monomers obtained by the resin component decomposition device 2 are supplied, and that performs methane fermentation of the organic waste and the monomers.

[0056] Resin-containing waste containing a resin component means waste containing one or more types of resin components, and the resin components contained in the resin-containing waste may be in the form of individual resin components or in the form of a mixed molded resin, but are resins that are at least partially hydrolyzed in the presence of an amine compound. Examples of such resins include resins and polyesters having at least an ester bond site, and specific examples of such resins include polylactic acid, polybutylene succinate, polybutylene adipate terephthalate, polyethylene terephthalate, polybutylene succinate adipate, polycaprolactone, polyhydroxyalkanoate (such as poly(3-hydroxybutyric acid)), polybutylene terephthalate, polyethylene furanoate, polyethylene naphthalate, and polycyclohexylene dimethylene terephthalate. From the viewpoint of excellent decomposability in the resin component decomposition device 2, the resin components contained in the resin-containing waste are preferably derived from biomass, more preferably a resin having lactic acid or 3-hydroxybutyric acid as a monomer component, polylactic acid, polyhydroxyalkanoate such as poly3-hydroxybutyric acid, and even more preferably polylactic acid or poly3-hydroxybutyric acid. In this embodiment, the resin-containing waste is waste containing, as a resin component, polylactic acid, which is a polyester derived from biomass, as well as polyethylene and polypropylene. In the following description, among the resin components contained in the resin-containing waste, resin components other than polylactic acid are also referred to as other resin components.

[0057] The organic waste containing a hard-to-decompose solid content means waste containing one or more types of solid organic matter. In this embodiment, the organic waste is sewage sludge.

[0058] In addition, the waste treatment system 1 according to the first embodiment is equipped with an undecomposed component gasification device 6 (undecomposed component gasification section) that thermally decomposes resin components that are not decomposed in the resin component decomposition device 2, among the resin components in the resin-containing waste supplied to the decomposition tank 3, to generate gas containing at least hydrogen and carbon monoxide.

[0059] As described above, the resin component decomposition device 2 includes the decomposition tank 3, and a hydrolysis treatment of a resin component (polylactic acid in this embodiment) is carried out in the presence of an amine compound in the decomposition tank 3. The decomposition tank 3 is configured so as to be capable of adjusting and maintaining the conditions of the hydrolysis treatment described below.

[0060] Examples of the amine compound used in the hydrolysis treatment include ammonia, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, and trimethylamine. In this embodiment, ammonia is used as the amine compound, and ammonia water is supplied into the decomposition tank 3 by an amine compound supplying means. The concentration of the ammonia water supplied to the decomposition tank 3 is not particularly limited, but is, for example, about 1 to 35 mass %. Alternatively, gaseous ammonia is used, and water required for hydrolysis can be added separately.

[0061] The pressure conditions for the above hydrolysis treatment (i.e., the pressure in the decomposition tank 3) are set in consideration of the amount and type of the amine compound in the decomposition tank 3 and the amount and type of the resin component (polylactic acid) to be treated. For example, the gauge pressure is preferably 0 to 10 MPaG, and more preferably 0 to 1 MPaG from the viewpoint of the apparatus structure.

[0062] The treatment time for the hydrolysis treatment is also set taking into consideration the amount and type of the amine compound in the decomposition tank 3 and the amount and type of the resin component (polylactic acid) to be treated, and is preferably 0.1 to 48 hours, for example, and more preferably 1 to 12 hours.

[0063] The temperature conditions for the hydrolysis treatment (i.e., the temperature inside the decomposition tank 3) are set taking into consideration the melting points of other resin components, and are, for example, 40°C or higher, preferably 50 to 220°C, and more preferably 80 to 160°C.

[0064] In addition, although not shown, the resin component decomposition apparatus 2 is equipped with a resin-containing waste supplying means for supplying an arbitrary amount of resin-containing waste to the decomposition tank 3, an amine compound supplying means for supplying an arbitrary amount of an amine compound into the decomposition tank 3, and a separation means for separating the monomer (lactic acid in this embodiment) obtained by decomposition of the resin components from the undecomposed resin components (the above-mentioned other resin components in this embodiment), and each of these means can be constructed by adopting a known method.

[0065] In this embodiment, the resin component decomposition apparatus 2 is configured to be able to recover water vapor and ammonia remaining in the decomposition tank 3 from the decomposition tank 3 after the polylactic acid has been hydrolyzed.

[0066] According to the resin component decomposition apparatus 2 having the above-mentioned configuration, resin-containing waste containing polylactic acid is supplied to the decomposition tank 3, and ammonia water is supplied to the decomposition tank 3, and the decomposition tank 3 is left for a predetermined time under predetermined treatment conditions, whereby the polylactic acid is hydrolyzed to lactic acid. Meanwhile, other resin components are not hydrolyzed. According to the resin component decomposition apparatus 2, the resulting lactic acid is separated from the other undecomposed resin components by the separation means. After the polylactic acid is hydrolyzed, water vapor and ammonia are recovered from the decomposition tank 3, and are reused as raw materials for ammonia water.

[0067] In this embodiment, the monomers separated by the separation means are supplied together with sewage sludge to the fermentation tank 5 of the methane fermentation apparatus 4 described later, and other undecomposed resin components are supplied to the undecomposed component gasification apparatus 6 described later.

[0068] As described above, the methane fermentation apparatus 4 is equipped with the fermentation tank 5, in which organic waste (sewage sludge in this embodiment) and monomers (lactic acid in this embodiment) are fermented to produce methane. Specifically, when the subject of methane fermentation is sewage sludge, water-soluble organic matter obtained by solubilizing the hard-to-decompose solids is fermented with acid, and methane is produced from the organic acid thus obtained. On the other hand, when the subject of methane fermentation is lactic acid, methane is produced from the lactic acid. In other words, the methane fermentation apparatus 4 allows methane fermentation of sewage sludge and methane fermentation of lactic acid to be carried out in parallel.

[0069] Here, since sewage sludge contains a hard-to-decompose solid content, in order to obtain methane by methane fermentation of the sewage sludge, it is necessary to go through a stage of solubilization of the hard-to-decompose solid content, which progresses at a slow rate. Therefore, when methane fermentation of only sewage sludge is performed in the fermenter 5, the volume load on the fermenter 5 is low. On the other hand, in the methane fermentation of monomers obtained by hydrolysis in the resin component decomposition device 2, the stage of solubilization of the hard-to-decompose solid content is not required, regardless of whether the monomer is an organic matter or an organic acid. Therefore, the methane fermentation device 4 of this embodiment is configured to supply the monomer to the fermenter 5 in which methane fermentation of sewage sludge is performed under a low volume load on the fermenter 5, so that the methane fermentation of sewage sludge and the methane fermentation of the monomer are compatible as described above. In this way, the methane fermentation device 4, which has a low volume load on the fermenter 5 when only sewage sludge is methane fermented, can be effectively used to efficiently produce methane from sewage sludge and monomers. In addition, in this embodiment, since the monomer is lactic acid, which is an organic acid, not only solubilization but also acid fermentation is unnecessary, compared to methane fermentation of sewage sludge, methane can be produced more efficiently. In this embodiment, from the viewpoint of effective use of the methane fermentation apparatus 4, the methane fermentation apparatus 4 is configured to perform methane fermentation of sewage sludge in a state where no monomer is supplied to the fermenter 5 and the volume load of sewage sludge (organic waste) on the fermenter 5 is 5 g CODcr / L / day or less (more preferably 3 g CODcr / L / day or less).

[0070] In this embodiment, methane is produced by methanogens in the fermenter 5 from hydrogen supplied from the undecomposed component gasifier 6 described below and carbon dioxide generated by methane fermentation of sewage sludge and lactic acid. Furthermore, in the fermenter 5 of this embodiment, acetic acid is produced by acetogens from carbon monoxide supplied from the undecomposed component gasifier 6.

[0071] The fermentation tank 5 is configured to be capable of adjusting and maintaining conditions suitable for methane fermentation of sewage sludge and lactic acid, production of methane from carbon dioxide and hydrogen, and production of acetic acid from carbon monoxide by microorganisms.

[0072] The temperature inside the fermenter 5 can be appropriately set within a wide range depending on the type of microorganism used, and is not particularly limited, but is, for example, about 20 to 60°C.

[0073] The treatment time for sewage sludge and lactic acid in the fermenter 5 is set taking into consideration the amount of sewage sludge and lactic acid, the type of microorganisms used, the temperature in the fermenter 5, etc., and is, for example, about 20 to 60 days for sewage sludge and about 1 to 10 days for lactic acid.

[0074] The methane fermentation apparatus 4 is also configured to be capable of carrying out a solid-liquid separation process for separating the treated material in the fermenter 5 into solid and liquid. The solid-liquid separation process can be carried out by known methods such as precipitation separation, mesh separation, membrane separation, and centrifugation, and is not particularly limited. In other words, the methane fermentation apparatus 4 is equipped with a solid-liquid separation means (not shown) having a configuration according to the method for carrying out the solid-liquid separation process. According to this solid-liquid separation process, a solid-containing fraction (solid content) can be obtained by separating the treated material into solid and liquid. The solid-containing fraction includes digested sludge, etc.

[0075] In addition, although not shown, the methane fermentation apparatus 4 is equipped with a sludge supplying means for supplying a desired amount of sewage sludge to the fermentation tank 5, an agitation means for agitating the fermentation tank 5 with the biogas generated in the fermentation tank 5, an extraction means for extracting the biogas containing methane and the like generated in the fermentation tank 5 and acetic acid to the outside, and a feeding means for feeding the solid content obtained by the solid-liquid separation process of the treated material to the undecomposed component gasification apparatus 6, and the like, and each of these means can be constructed using known techniques.

[0076] According to the methane fermentation apparatus 4 having the above-mentioned configuration, lactic acid obtained by the resin component decomposition apparatus 2 is supplied into the fermentation tank 5 together with sewage sludge supplied from the outside, and methane fermentation of the sewage sludge and methane fermentation of the lactic acid proceed in parallel in the fermentation tank 5 to generate methane. In addition, gas containing hydrogen and carbon monoxide is supplied from the undecomposed component gasification apparatus 6, and methane is generated from the carbon dioxide generated by methane fermentation and the hydrogen supplied from the undecomposed component gasification apparatus 6, and acetic acid is generated based on the carbon monoxide supplied from the undecomposed component gasification apparatus 6. Then, the generated methane and acetic acid are taken out to the outside. In addition, according to the resin component decomposition apparatus 2 of this embodiment, the treated material in the fermentation tank 5 is separated into solid and liquid by a solid-liquid separation process, and the obtained solid content is sent to the undecomposed component gasification apparatus 6.

[0077] In this embodiment, the undecomposed component gasifier 6 thermally decomposes the other resin components that were not decomposed in the resin component decomposition device 2 to generate gas containing hydrogen and carbon monoxide. The generated gas is supplied to the fermentation tank 5 through a biogas distribution line or the like provided as an agitation means in the methane fermentation device 4. Such an undecomposed component gasifier 6 can be a conventionally known waste gasification treatment device, and examples of such devices include a low-temperature gasifier (not shown) that combusts the other resin components at about 600 to 800°C, and a high-temperature gasifier (not shown) that receives the gaseous material from the low-temperature gasifier and thermally decomposes the gaseous material at about 1400°C with oxygen and water vapor added.

[0078] In this embodiment, the undecomposed component gasifier 6 is configured to be supplied with solids separated by solid-liquid separation processing in the methane fermentation apparatus 4. In other words, the undecomposed component gasifier 6 thermally decomposes the solids supplied from the methane fermentation apparatus 4 in addition to the above-mentioned other resin components to generate gas containing hydrogen and carbon monoxide.

[0079] Next, a method for treating waste by the waste treatment system 1 (waste treatment method) will be described.

[0080] First, resin-containing waste is supplied to the decomposition tank 3 of the resin component decomposition device 2, and ammonia water is supplied into the decomposition tank 3. The temperature and pressure in the decomposition tank 3 are adjusted to be within a predetermined range, and processing is carried out for a predetermined time, thereby hydrolyzing polylactic acid to lactic acid (resin component decomposition process).

[0081] Here, in this embodiment, the resin-containing waste is one in which the amount of polylactic acid, which is a resin component that is decomposed by the resin component decomposition apparatus 2, and the amount of other resin components that are not decomposed are adjusted. That is, in the resin-containing waste of this embodiment, the amount of polylactic acid that can be decomposed by the resin component decomposition apparatus 2, among the resin components contained in the resin-containing waste, is adjusted so that the resin component decomposition apparatus 2 can obtain lactic acid at a level equivalent to the amount that can be supplied to the fermenter 5, which is determined according to the remaining volume load obtained by subtracting the volume load of the sewage sludge supplied to the fermenter 5 from the total volume load of the fermenter 5.

[0082] In this way, by adjusting the amount of polylactic acid in the resin-containing waste, it is possible to decompose the polylactic acid and obtain lactic acid in an amount equivalent to the above-mentioned supplyable amount, and the obtained lactic acid can be supplied to the fermenter 5.

[0083] The total volume load of the fermenter 5 is, for example, 20 gCODcr / L / day. Therefore, in this embodiment, the amount of lactic acid that can be supplied to the fermenter 5 is determined according to 17 to 18 gCODcr / L / day, which is obtained by subtracting the volume load of sewage sludge (for example, 2 to 3 gCODcr / L / day) from the total volume load of the fermenter 5, 20 gCODcr / L / day. The amount of polylactic acid in the resin-containing waste to be supplied to the decomposition tank 3 is adjusted so that lactic acid equivalent to the determined amount that can be supplied is obtained.

[0084] Furthermore, in this embodiment, the amount of other resin components contained in the resin-containing waste that are not decomposed in the resin component decomposition apparatus 2 is adjusted so that the amount of hydrogen needed to methanate the carbon dioxide generated by the methane fermentation of sewage sludge and lactic acid in the methane fermentation apparatus 4 is produced in the undecomposed component gasification apparatus 6.

[0085] In this way, by adjusting the amount of other resin components in the resin-containing waste, the other resin components are gasified to obtain the amount of hydrogen needed to methanate the carbon dioxide generated in the methane fermentation apparatus 4, and the obtained hydrogen can be supplied to the fermentation tank 5.

[0086] Next, the lactic acid obtained by decomposition of the polylactic acid is separated from other undecomposed resin components. Then, the entire amount of the separated lactic acid is supplied to the fermentation tank 5 of the methane fermentation device 4 together with the sewage sludge. Meanwhile, the entire amount of the other resin components is supplied to the undecomposed component gasification device 6. In this embodiment, the water vapor and ammonia remaining in the fermentation tank 5 after the hydrolysis treatment are collected and reused as raw materials for ammonia water.

[0087] The other resin components are supplied to an undecomposed component gasifier 6, where they are gasified to generate gas containing hydrogen and carbon monoxide (undecomposed component gasification step). The generated gas is then supplied to the fermentation tank 5 of the methane fermentation device 4.

[0088] Lactic acid and sewage sludge are supplied to the fermentation tank 5 of the methane fermentation apparatus 4, and then methane fermentation of the lactic acid and the sewage sludge are carried out in parallel in the methane fermentation apparatus 4 to produce methane (methane fermentation process). Furthermore, in the methane fermentation process of this embodiment, methane is produced in the fermentation tank 5 from carbon dioxide generated in conjunction with the methane fermentation of the lactic acid and the sewage sludge and hydrogen supplied from the undecomposed component gasification apparatus 6, and acetic acid is produced from the carbon monoxide supplied from the undecomposed component gasification apparatus 6.

[0089] In the methane fermentation process, a solid-liquid separation process is appropriately performed, and the treated material in the fermentation tank 5 is separated into solid and liquid to obtain a solid-containing fraction containing digested sludge, etc., and the solid-containing fraction is fed to the undecomposed component gasification device 6. When the solid-containing fraction is fed to the undecomposed component gasification device 6, the solid-containing fraction is gasified in the undecomposed component gasification device 6 to generate gas containing hydrogen and carbon monoxide. The gas is fed to the fermentation tank 5 of the methane fermentation device 4.

[0090] Then, after a predetermined time has elapsed since the sewage sludge and lactic acid were supplied into the fermentation tank 5, the methane and acetic acid in the fermentation tank 5 are discharged to the outside.

[0091] Second Embodiment Next, a waste treatment system and a waste treatment method according to a second embodiment of the present invention will be described with reference to the drawings.

[0092] 2 is a diagram showing a schematic configuration of a waste treatment system 10 according to a second embodiment. The waste treatment system 10 according to the second embodiment differs from the first embodiment mainly in that it includes an undecomposed component combustion device 11 instead of an undecomposed component gasification device. The waste treatment system 10 according to the second embodiment will be described below, but a description of the same configuration as the waste treatment system 1 according to the first embodiment will be omitted.

[0093] As shown in Figure 2, the waste treatment system 10 according to the second embodiment is equipped with an undecomposed component combustion device 11 (undecomposed component combustion section) that combusts the resin components in the resin-containing waste supplied to the decomposition tank 3 that have not been decomposed in the resin component decomposition device 2.

[0094] Specifically, in this embodiment, the undecomposed component combustion device 11 generates heat by burning other resin components that were not decomposed in the resin component decomposition device 2 (i.e., resin components other than polylactic acid among the resin components in the resin-containing waste). The generated heat is then supplied to the decomposition tank 3 of the resin component decomposition device 2 and the fermentation tank 5 of the methane fermentation device 4 via a heat medium, and is configured to be used to maintain the temperatures of the decomposition tank 3 and the fermentation tank 5. Such an undecomposed component combustion device 11 can use a conventionally known waste incineration device.

[0095] In addition, in this embodiment, the solid-containing fraction separated by the solid-liquid separation process in the methane fermentation apparatus 4 is supplied, and the undecomposed component combustion apparatus 11 burns the solid-containing fraction supplied from the methane fermentation apparatus 4 in addition to the other resin components described above to generate heat.

[0096] Next, a method for treating waste by the waste treatment system 10 (waste treatment method) will be described.

[0097] First, a resin component decomposition process is carried out in the same manner as when waste is treated by the waste treatment system 1 according to the first embodiment, and lactic acid obtained by decomposition of polylactic acid is separated. The entire amount of separated lactic acid is supplied to the fermentation tank 5 of the methane fermentation device 4 together with sewage sludge, and methane fermentation of the lactic acid and that of the sewage sludge are carried out in parallel.

[0098] In this embodiment, the amount of polylactic acid in the resin-containing waste to be supplied to the decomposition tank 3 is adjusted in the same manner as in the first embodiment. Therefore, it is possible to obtain lactic acid by decomposing polylactic acid in an amount equivalent to the amount that can be supplied to the fermentation tank 5, which is determined according to the remaining volume load obtained by subtracting the volume load of the sewage sludge supplied to the fermentation tank 5 from the total volume load of the fermentation tank 5, and the obtained lactic acid can be supplied to the fermentation tank 5.

[0099] Meanwhile, the remaining resins that were not decomposed in the resin component decomposition step are entirely supplied to an undecomposed component combustion device 11, where the remaining resin components are combusted to generate heat (undecomposed component combustion step).The generated heat is then supplied to the decomposition tank 3 and the fermentation tank 5, and is utilized to maintain the decomposition tank 3 and the fermentation tank 5 at a predetermined temperature.

[0100] In this embodiment, the solid-containing fraction obtained by solid-liquid separation of the treated material in the fermenter 5 is fed to the undecomposed component combustion device 11. When the solid-containing fraction is fed to the undecomposed component combustion device 11, the solid-containing fraction is combusted in the undecomposed component combustion device 11 to generate heat, which is used to maintain the temperatures of the decomposition tank 3 and the fermenter 5.

[0101] In this embodiment, after a predetermined time has elapsed since the sewage sludge and lactic acid were supplied into the fermenter 5, the methane in the fermenter 5 is discharged to the outside.

[0102] As described above, according to the waste treatment systems and waste treatment methods of the first and second embodiments, methane can be obtained by methane fermentation of lactic acid obtained by decomposing polylactic acid in resin-containing waste using equipment for methane fermentation of sewage sludge. In other words, methane can be produced from polylactic acid in resin-containing waste without going through syngas. Therefore, methane can be produced from resin-containing waste while reducing the amount of methane produced through syngas, and an increase in the cost required for recycling resin-containing waste can also be suppressed.

[0103] (Experimental Example) An experimental example is given below. 5 g of 28% by mass ammonia water was added to 2.5 g of six resins, namely polylactic acid (PLA, TE2000 manufactured by Unitika Ltd.), poly 3-hydroxybutyric acid (PHB, synthesized by Osaka Gas Co., Ltd.), polybutylene succinate (PBS, TH803S manufactured by XINJIANG BLUE RIDGE TUNHE CHEMICAL INDUSTRY JOINT STOCK CO., LTD.), polybutylene adipate terephthalate (PBAT, TH801H manufactured by XINJIANG BLUE RIDGE TUNHE CHEMICAL INDUSTRY JOINT STOCK CO., LTD.), polypropylene (PP, FW4BT manufactured by Japan Polypropylene Corporation), and low density polyethylene (LLDPE, UF230 manufactured by Japan Polyethylene Corporation), and the mixture was heated at 120°C for 1 hour and 4 hours in a sealed state. After heating, the weight of the solid matter remaining in the reaction solution was measured, and the decomposition rate was calculated by the following formula. The results are summarized in Table 1. Decomposition rate (%) = (amount of resin before reaction (2.5 g) - amount of solid after reaction) / amount of resin before reaction (2.5 g) x 100

[0104] [Table 1]

[0105] As shown in Table 1, PLA and PHB were completely decomposed, whereas PBS and PBAT were decomposed to some extent, though at a slow rate, and the decomposition rate of PLA and PHB was particularly fast. On the other hand, PP and LLDPE were not decomposed or were hardly decomposed. From this, it was confirmed that if the resin-containing waste contains polylactic acid or a resin component that is easily decomposed by the resin component decomposition device 2 as a resin component, the polylactic acid can be decomposed to lactic acid by the resin component decomposition device 2, and other resin components such as PHB can also be decomposed to their constituent components. In addition, if the resin-containing waste contains a resin component that is extremely difficult to decompose by the resin component decomposition device 2, such as PP or LLDPE, it was confirmed that when the resin-containing waste is supplied to the resin component decomposition device 2, the resin component to be supplied to the undecomposed component gasification device 6 and the undecomposed component combustion device 11 can be secured. In addition, such a resin component that is extremely difficult to decompose by the resin component decomposition device 2 may be contained in the resin-containing waste in a state where it is kneaded with a resin that can be decomposed by the resin component decomposition device 2.

[0106] [Another embodiment] [1] In the first embodiment, the undecomposed component gasification device 6 is provided, and in the second embodiment, the undecomposed component combustion device 11 is provided, but both the undecomposed component gasification device and the undecomposed component combustion device may not be provided. In this case, the resin components that are not decomposed in the resin component decomposition device 2 may be treated by a separate appropriate method. Also, both the undecomposed component gasification device and the undecomposed component combustion device may be provided.

[0107] [2] In each of the above embodiments, the resin-containing waste contains polylactic acid as a resin component decomposable by the resin component decomposition apparatus 2, but this is not limited thereto. In addition to polylactic acid, another decomposable resin component may be contained, or another decomposable resin component may be contained instead of polylactic acid. The other decomposable resin component is not particularly limited as long as it is a resin that is hydrolyzed in the presence of an amine compound. In addition, although the embodiment is such that lactic acid, which is an organic acid, is supplied to the methane fermentation apparatus 4 as a monomer, the substance supplied to the methane fermentation apparatus 4 is not particularly limited as long as it is a monomer obtained by decomposition in the resin component decomposition apparatus 2.

[0108] [3] In each of the above embodiments, the organic waste containing the hard-to-decompose solid content is sewage sludge, but the present invention is not limited to this.

[0109] [4] In each of the above embodiments, the methane fermentation apparatus 4 is configured to be capable of performing solid-liquid separation processing, but the methane fermentation apparatus 4 may not be configured to be capable of performing solid-liquid separation processing.

[0110] [5] In each of the above embodiments, the methane fermentation apparatus 4 is configured to perform methane fermentation of sewage sludge when no monomer is supplied to the fermenter 5 and the volume load of sewage sludge to the fermenter 5 is 5 g CODcr / L / day or less. However, the methane fermentation apparatus 4 may also be configured to perform methane fermentation of sewage sludge when no monomer is supplied to the fermenter 5 and the volume load of sewage sludge to the fermenter 5 is more than 5 g CODcr / L / day.

[0111] [6] In each of the above embodiments, the amount of polylactic acid in the resin-containing waste is adjusted, but the amount of polylactic acid in the resin-containing waste may not be adjusted. In the first embodiment, the amount of other resin components (resin components not decomposed by the resin component decomposition device 2) in the resin-containing waste is adjusted, but the amount of other resin components in the resin-containing waste may not be adjusted. For example, the required amount of polylactic acid and other resin components is not always collected at the treatment facility. Therefore, the resin-containing waste collected at the treatment facility may be subjected to recycling treatment without adjusting the amount of the resin components.

[0112] [7] In each of the above embodiments, after the hydrolysis of polylactic acid, the water vapor and ammonia remaining in the decomposition tank 3 are recovered from the decomposition tank 3 and reused. However, the water vapor and ammonia remaining in the decomposition tank 3 may be discarded without being recovered.

[0113] [8] In the first embodiment, the hydrogen and carbon monoxide produced in the undecomposed component gasifier 6 are supplied to the fermenter 5 of the methane fermenter 4, but the present invention is not limited to this. For example, only one of them may be supplied to the fermenter 5, and the other may be recovered as a chemical raw material or fuel gas. Also, both the hydrogen and carbon monoxide produced in the undecomposed component gasifier 6 may not be supplied to the fermenter 5, but may be recovered as a chemical raw material or fuel gas.

[0114] [9] In the above first embodiment, acetic acid is produced from carbon monoxide in the fermenter 5 of the methane fermentation apparatus 4. However, the present invention may be adapted so that acetic acid is not produced in the fermenter 5. Alternatively, the present invention may be adapted so that a production tank to which carbon monoxide is supplied is provided, and an acetic acid production section that produces acetic acid from carbon monoxide is provided separately from the methane fermentation apparatus 4.

[0115]

[10] In the first embodiment, the carbon monoxide produced in the undecomposed component gasifier 6 is supplied to the fermenter 5 of the methane fermenter 4, but the present invention is not limited to this. For example, the carbon monoxide produced in the undecomposed component gasifier 6 may be burned, and the generated heat may be used in the resin component decomposition device 2 or the methane fermenter 4, or in other devices.

[0116]

[11] In the above second embodiment, the heat generated in the undecomposed component combustion device 11 is utilized in both the resin component decomposition device 2 and the methane fermentation device 4, but it may be utilized in only one of the resin component decomposition device 2 and the methane fermentation device 4, or the heat generated in the undecomposed component combustion device 11 may be utilized in another device.

[0117] The configurations disclosed in the above embodiments (including other embodiments) can be applied in combination with configurations disclosed in other embodiments, provided that no contradiction arises. Furthermore, the embodiments disclosed in this specification are illustrative, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope that does not deviate from the purpose of the present invention. [Industrial Applicability]

[0118] INDUSTRIAL APPLICABILITY The present invention can be used in a system and method for treating resin-containing waste that contains a resin component. [Explanation of symbols]

[0119] 1,10: Waste treatment system 2: Resin component decomposition device (resin component decomposition section) 3: Decomposition tank 4: Methane fermentation equipment (methane fermentation section) 5: Fermentation tank 6: Undecomposed component gasification device (undecomposed component gasification section) 11: Undecomposed component combustion device (undecomposed component combustion section)

Claims

1. A system for treating resin-containing waste containing a resin component, comprising: a resin component decomposition section having a decomposition tank to which the resin-containing waste is supplied, and heating the resin-containing waste in the presence of an amine compound to hydrolyze at least a part of the resin components into monomers; A methane fermentation section having a fermenter to which organic waste containing a hard-to-decompose solid content and the monomer obtained in the resin component decomposition section are supplied, and the organic waste and the monomer are fermented into methane, The resin-containing waste is such that the amount of the resin component that can be decomposed in the resin component decomposition section is adjusted so that the amount of the monomer that can be obtained in the resin component decomposition section is equal to or less than the amount that can be supplied to the fermenter, which is determined according to a remaining volume load obtained by subtracting the volume load of the organic waste supplied to the fermenter from the total volume load of the fermenter, The methane fermentation section is configured to perform methane fermentation of the organic waste in a state where the volume load of the organic waste on the fermentation tank is 5 g CODcr / L / day or less when the monomer is not supplied to the fermentation tank.

2. 2. The waste treatment system according to claim 1, further comprising an undecomposed component gasification section that thermally decomposes the resin components in the resin-containing waste supplied to the decomposition tank that have not been decomposed in the resin component decomposition section, thereby generating a gas containing at least hydrogen and carbon monoxide.

3. 3. The waste treatment system according to claim 2, wherein at least the hydrogen generated in the undecomposed component gasification section is supplied to the fermentation tank.

4. 4. The waste treatment system according to claim 2, further comprising an acetic acid production section which produces acetic acid from the carbon monoxide, the acetic acid production section further comprising a production tank to which at least the carbon monoxide is supplied from the gas produced in the undecomposed component gasification section.

5. The resin-containing waste is The amount of the resin component that can be decomposed in the resin component decomposition unit is adjusted so that the monomer can be obtained in the resin component decomposition unit in an amount equivalent to the amount that can be supplied to the fermenter, which is determined according to a remaining volume load obtained by subtracting the volume load of the organic waste supplied to the fermenter from the total volume load of the fermenter; The waste treatment system according to any one of claims 2 to 4, wherein the amount of the resin components that is not decomposed in the resin component decomposition section is adjusted so that an amount of hydrogen necessary for methanation of carbon dioxide generated by methane fermentation of the organic waste and the monomer in the methane fermentation section is generated in the undecomposed component gasification section.

6. The methane fermentation unit is configured to be able to perform solid-liquid separation processing, 6. The waste treatment system according to claim 2, wherein the solid content obtained in the solid-liquid separation process in the methane fermentation section is supplied to the undecomposed component gasification section.

7. The waste treatment system according to any one of claims 2 to 6, wherein the heat generated by burning the carbon monoxide produced in the undecomposed component gasification section is utilized in the resin component decomposition section or the methane fermentation section.

8. The waste treatment system according to claim 1 , further comprising an undecomposed component combustion section that combusts the resin components in the resin-containing waste supplied to the decomposition tank that have not been decomposed in the resin component decomposition section.

9. The waste treatment system according to claim 8 , wherein heat generated in the undecomposed component combustion section is utilized in the resin component decomposition section or the methane fermentation section.

10. The methane fermentation unit is configured to be able to perform solid-liquid separation processing, 10. The waste treatment system according to claim 8, wherein the solid content obtained in the solid-liquid separation treatment in the methane fermentation section is supplied to the undecomposed component combustion section.

11. 11. The waste treatment system according to claim 1, wherein the resin component decomposition section is configured to recover and reuse the water vapor and the amine compound generated in the decomposition tank.

12. The resin component contains a resin having at least an ester bond site, 12. The waste treatment system according to claim 1, wherein the resin component decomposition section decomposes the resin having the ester bond site into each of the constituent components as the monomers.

13. The resin component contains at least polyester, 13. The waste treatment system according to claim 1, wherein the resin component decomposition section decomposes the polyester into each of the constituent components as the monomers.

14. The resin component contains at least a resin derived from biomass, The waste treatment system according to any one of claims 1 to 13, wherein the resin component decomposition section decomposes the biomass-derived resin into each of the constituent components as the monomers.

15. The resin component includes a resin having lactic acid or 3-hydroxybutyric acid as a monomer component, The waste treatment system according to any one of claims 1 to 14, wherein the resin component decomposition section decomposes a resin having lactic acid or 3-hydroxybutyric acid as the monomer component into the lactic acid or 3-hydroxybutyric acid as the monomer.

16. The resin component contains at least polylactic acid, 16. The waste treatment system according to claim 1, wherein the resin component decomposition section decomposes the polylactic acid into lactic acid as the monomer.

17. The resin component contains at least polyhydroxyalkanoate, 17. The waste treatment system according to claim 1, wherein the resin component decomposition section decomposes the polyhydroxyalkanoate into each of the constituent components as the monomer.

18. The resin component contains at least poly(3-hydroxybutyric acid), 18. The waste treatment system according to claim 1, wherein the resin component decomposition section decomposes the poly 3-hydroxybutyric acid into 3-hydroxybutyric acid as the monomer.

19. The waste treatment system according to any one of claims 1 to 18, wherein the organic waste is sewage sludge.

20. A method for treating resin-containing waste containing a resin component, comprising the steps of: a resin component decomposition step of supplying the resin-containing waste to a decomposition tank and heating the resin-containing waste in the presence of an amine compound to hydrolyze at least a portion of the resin component into a monomer; a methane fermentation step of supplying organic waste containing a hard-to-decompose solid content and the monomer obtained in the resin component decomposition step to a fermenter and subjecting the organic waste and the monomer to methane fermentation; The resin-containing waste is such that the amount of the resin component that can be decomposed in the resin component decomposition step is adjusted so that the amount of the monomer that can be decomposed in the resin component decomposition step is equal to or less than the amount that can be supplied to the fermenter, which is determined according to a remaining volume load obtained by subtracting the volume load of the organic waste supplied to the fermenter from the total volume load of the fermenter, The methane fermentation step is configured to perform methane fermentation of the organic waste in a state where the monomer is not supplied to the fermentation tank and the volume load of the organic waste to the fermentation tank is 5 g CODcr / L / day or less.

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