Organic waste treatment method and device

Abstract

To provide a method and an apparatus for treating organic waste material which suppresses malodor due to a secular change of the organic waste material containing shells for which subcritical water treatment is performed.SOLUTION: Organic waste material containing shells is projected into a pressure container 21. Subsequently, steam is supplied to the pressure container 21 and, in the pressure container 21, such subcritical water treatment as to perform heating and pressurization by using water in the subcritical state while stirring the organic waste material containing shells, and as to dissolve the organic waste material containing shells by using water being gotten to the subcritical state from the state of steam according to heating and pressurization is performed. The organic waste material containing the shells to which subcritical water treatment is performed is taken out from the pressure container 21 and is cooled on a cooling part 3. Fungus for suppressing malodor due to a secular change of the organic waste material containing shells to which the subcritical water treatment is performed is added to the organic waste material containing shells to which the subcritical water treatment is performed, while the cooling part 3 cools the organic waste material containing the shells to which the subcritical water treatment is performed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and apparatus for treating organic waste. [Background technology]

[0002] Conventionally, subcritical water treatment devices have been proposed that perform subcritical water treatment to treat organic waste such as waste plastics generated by dispersing the compressed material of PET bottles from which the surface layer has been compressed and removed (for example, Patent Document 1).

[0003] In such a subcritical water treatment apparatus, organic waste is put into a pressure vessel of the subcritical water treatment apparatus. Then, steam is supplied to the pressure vessel, and the organic waste is heated and pressurized in the pressure vessel while being stirred, and subcritical water treatment is performed in which the organic waste is decomposed using water that has been brought from a steam state to a subcritical state by the heating and pressurization. The water that has been brought into a subcritical state is, for example, water at 160 to 220°C and 1.6 to 2.3 MPa.

[0004] Organic waste that has been treated with subcritical water can be used as embankments, etc. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-127845 A Summary of the Invention [Problem to be solved by the invention]

[0006] Organic waste may include shells, shells containing sludge, shells containing soil, etc. The shell-containing organic waste that was treated with subcritical water was odorless immediately after the treatment, but after more than two weeks had passed, a foul odor was generated due to the change over time of the shell-containing organic waste that was treated with subcritical water.

[0007] In addition, when waste plastics were treated with subcritical water, no unpleasant odor was generated due to changes over time in the waste plastics that had been treated with subcritical water, even immediately after the treatment or more than two weeks after the treatment.

[0008] An object of the present invention is to provide an organic waste treatment method and apparatus capable of suppressing odors caused by changes over time in organic waste, including shells, that have been subjected to subcritical water treatment. [Means for solving the problem]

[0009] The organic waste treatment method according to the present invention comprises a feeding step of feeding organic waste containing shells into a pressure vessel; a subcritical water treatment step of supplying steam to the pressure vessel and heating and pressurizing the organic waste containing shells while stirring it inside the pressure vessel, and performing subcritical water treatment to decompose the organic waste containing shells using water that has been brought from a steam state to a subcritical state by the heating and pressurization; and a cooling step of removing the organic waste containing shells that has been subjected to the subcritical water treatment from the pressure vessel and cooling it, the cooling step including a fungus addition step of adding fungi to the organic waste containing shells that has been subjected to the subcritical water treatment in order to suppress odors caused by changes over time in the organic waste containing shells that has been subjected to the subcritical water treatment.

[0010] In the organic waste treatment method according to the present invention, the fungi are preferably soil bacteria.

[0011] In the organic waste treatment method according to the present invention, the soil bacteria are preferably actinomycetes.

[0012] The organic waste treatment method according to the present invention preferably further comprises a heavy metal treatment agent addition step of adding a heavy metal treatment agent to the organic waste containing shells immediately before, simultaneously with, or immediately after the input step.

[0013] In the organic waste treatment method according to the present invention, the heavy metal treatment agent is preferably rice husk.

[0014] The organic waste treatment apparatus according to the present invention comprises a subcritical water treatment apparatus having a pressure vessel for performing subcritical water treatment in which water is supplied to the apparatus, and the organic waste containing shells is heated and pressurized while being stirred, and the organic waste containing shells is decomposed using water that has been brought from a steam state to a subcritical state by the heating and pressurization, and a cooling section for cooling the organic waste containing shells that has been subjected to the subcritical water treatment and that has been removed from the pressure vessel. While the cooling section is cooling the organic waste containing shells that has been subjected to the subcritical water treatment, fungi are added to the organic waste containing shells that has been subjected to the subcritical water treatment in order to suppress odors caused by changes over time in the organic waste containing shells that has been subjected to the subcritical water treatment.

[0015] In the organic waste treatment device according to the present invention, the fungi are preferably soil bacteria.

[0016] In the organic waste treatment device according to the present invention, the soil bacteria are preferably actinomycetes.

[0017] In the organic waste treatment device according to the present invention, preferably a heavy metal treatment agent is added to the organic waste containing shells immediately before the organic waste containing shells is charged into the pressure vessel, simultaneously with the charging of the organic waste containing shells into the pressure vessel, or immediately after the charging of the organic waste containing shells into the pressure vessel.

[0018] In the organic waste treatment device according to the present invention, the heavy metal treatment agent is preferably rice husk. Effect of the Invention

[0019] According to the present invention, it is possible to suppress the offensive odor caused by the change over time of organic waste containing shells that has been subjected to subcritical water treatment. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic diagram of an organic waste treatment device according to an embodiment of the present invention. [Diagram 2]1 is a front view showing details of a portion of an organic waste treatment device according to an embodiment of the present invention. [Diagram 3] 1 is a side view showing details of a portion of an organic waste treatment device according to an embodiment of the present invention. [Figure 4] 1 is a plan view showing details of a portion of an organic waste treatment device according to an embodiment of the present invention; [Diagram 5] FIG. 2 is a block diagram of a control system of the organic waste treatment apparatus according to the embodiment of the present invention. [Figure 6] 3 is a flow chart showing an example of steps of an organic waste treatment method performed by an organic waste treatment device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The organic waste treatment method and apparatus according to the present invention will be described with reference to the drawings. Fig. 1 is a schematic diagram of an organic waste treatment device according to an embodiment of the present invention. Figs. 2 to 4 are a front view, a side view, and a plan view showing details of a part of an organic waste treatment device according to an embodiment of the present invention. Fig. 5 is a block diagram of a control system of an organic waste treatment device according to an embodiment of the present invention.

[0022] 1 to 4 shows an organic waste treatment apparatus 1 that treats organic waste containing shells. The organic waste containing shells includes shells, shells containing sludge, shells containing soil, and the like.

[0023] As shown in Fig. 1, an organic waste treatment device 1 receives a treatment object together with a heavy metal treatment agent, performs subcritical water treatment on the treatment object, and removes and cools the treatment object after the subcritical water treatment. The heavy metal treatment agent is, for example, rice husk.

[0024] The organic waste treatment device 1 adds bacteria to the object to be treated that has been treated with subcritical water during cooling of the object to be treated that has been treated with subcritical water. The bacteria to suppress odors caused by changes over time in the object to be treated is, for example, soil bacteria. An example of the soil bacteria is actinomycetes.

[0025] The organic waste treatment device 1 includes a subcritical water treatment device 2 shown in Figures 1 to 4, a cooling unit 3 shown in Figures 1 to 4, and a tent house 4 shown in Figures 1 to 4. The subcritical water treatment device 2 is provided on a concrete foundation (not shown) formed on the ground, and is fixed to the concrete foundation by anchor bolts 5 shown in Figures 2 and 3.

[0026] The subcritical water treatment apparatus 2 includes a pressure vessel 21 shown in Figures 1 to 3, a steam discharge apparatus 22 shown in Figures 1 to 3, a steam supply apparatus 23 shown in Figures 1 and 2, a steam on-off valve 24 shown in Figures 2 and 5, an on-off valve drive device 25 shown in Figures 2 and 5, and an agitator 26 shown in Figures 1 and 2. The subcritical water treatment apparatus 2 further includes a control device 27 shown in Figure 5 and a steam discharge valve drive device 28 shown in Figure 5.

[0027] The pressure vessel 21 is equipped with an inlet 21A shown in Figures 1 to 3, an outlet 21B shown in Figures 1 and 2, steam inlets 21C (two locations) shown in Figures 1, 2 and 4, a clutch door 21D shown in Figures 1 to 3, and a handle 21E shown in Figures 2 and 4. The inlet 21A is formed in a cylindrical shape protruding from the top of the pressure vessel 21 for introducing the material to be treated.

[0028] The outlet 21B is provided for discharging the treatment object that has been subjected to the subcritical water treatment to the cooling section 3. The steam inlet 21C is provided for injecting steam from the steam supply device 23 into the pressure vessel 21.

[0029] The clutch door 21D is provided at the upper end of the input port 21A in order to open and close the input port 21A. The handle 21E is provided at one end of the outlet 21B in order to open and close the outlet 21B, and opens the outlet 21B when the treatment object that has been subjected to the subcritical water treatment is discharged into the cooling section 3.

[0030] The water vapor exhaust device 22 is formed in a cylindrical shape erected upward from the upper end of the pressure vessel 21, and has water vapor exhaust ports 22A, 22B shown in Figures 2 to 4, and a water vapor exhaust valve 22C shown in Figure 5. The water vapor exhaust ports 22A, 22B are provided on the side surface and upper end of the cylindrical body in order to exhaust water vapor to the outside.

[0031] The water vapor supplying device 23 includes a boiler 23A shown in Fig. 2 and a pressure regulating valve 23B shown in Fig. 2 and Fig. 4. The boiler 23A generates water vapor at a predetermined temperature and pressure (for example, 120 to 500°C and 0.2 to 40 MPa).

[0032] The steam generated by the boiler 23A is supplied from the steam inlet 21C into the pressure vessel 21 via a pressure regulating valve 23B and a steam on-off valve 24. The steam on-off valve 24 is opened and closed by an on-off valve drive device 25 controlled by a control device 27.

[0033] The stirring device 26 has a rotating shaft 26A shown in Figures 1 and 2, and a plurality of stirring blades 26B shown in Figure 2. The rotating shaft 26A is disposed so as to penetrate horizontally through approximately the center inside the pressure vessel 21. The stirring blades 26B are attached to the rotating shaft 26A at a plurality of points in the longitudinal direction thereof, extending in the radial direction.

[0034] 2, 3 and 5 is coupled to one end of the rotating shaft 26A, and the rotating shaft 26A is driven by the motor 7 coupled to the reducing gear 6 and coupled to the motor 7, which is coupled to the reducing gear 6 and is shown in FIGS. 1 to 3, to agitate the material to be treated in the pressure vessel 21. During normal operation, the rotating shaft 26A is switched between rotating clockwise and counterclockwise at regular intervals.

[0035] When the rotating shaft 26A rotates clockwise, the agitating blade 26B sends the material to be treated from the outlet 21B side toward the motor 7. On the other hand, when the rotating shaft 26A rotates counterclockwise, the agitating blade 26B sends the material to be treated from the motor 7 side toward the outlet 21B.

[0036] Therefore, when the object to be treated that has been subjected to the subcritical water treatment is discharged to the cooling section 3, the rotating shaft 26A rotates counterclockwise, and the stirring blades 26B send the object to be treated in the direction from the motor 7 side to the outlet 21B.

[0037] The control device 27 is made up of a CPU, and receives a detected temperature signal from a temperature sensor 30 shown in Figures 1, 4 and 5, and a detected pressure signal from a pressure sensor 31 shown in Figures 1, 4 and 5. The temperature sensor 30 is disposed in the longitudinal center of the pressure vessel 21 and detects the temperature above the stirring blade 26B. The pressure sensor 31 is attached to the clutch door 21D and detects the pressure inside the pressure vessel 21.

[0038] During critical water treatment, the control device 27 controls the on-off valve drive device 25 based on the detected temperature signal and the detected pressure signal to drive the steam on-off valve 24. By driving the steam on-off valve 24, the amount of steam supplied to the pressure vessel 21 is adjusted, and the water (steam) in the pressure vessel 21 becomes subcritical water (for example, water at 160 to 220°C and 1.6 to 2.3 MPa).

[0039] In addition, after the critical water treatment is completed, the control device 27 controls the water vapor exhaust valve drive device 28 to drive the water vapor exhaust valve 22C and exhaust the water vapor from within the pressure vessel 21 in order to dry the treatment object that has been subjected to the subcritical water treatment.

[0040] Furthermore, the control device 27 receives a detected rotational speed signal from a rotational speed sensor 32 shown in Fig. 5 and a detected rotational torque signal from a rotational torque sensor 33 shown in Fig. 5. The rotational speed sensor 32 is attached to the rotating shaft 26A and detects the rotational speed of the rotating shaft 26A. The rotational torque sensor 33 is attached to the rotating shaft 26A and detects the rotational torque of the rotating shaft 26A.

[0041] The control device 27 controls the speed reducer 6 based on the detected rotational speed signal and the detected rotational torque signal, thereby controlling the rotational speed of the rotating shaft 26A.

[0042] The cooling section 3 is made of a metal that is cooled by air or water. The cooling section 3 cools the object to be treated that has been subjected to the subcritical water treatment after it is discharged from the outlet 21B and supplied. The cooling section 3 also adds fungi to the object to be treated that has been subjected to the subcritical water treatment during the cooling of the object to be treated that has been subjected to the subcritical water treatment, for suppressing bad odors caused by changes over time in the object to be treated.

[0043] The tent house 4 is movable along rails 8 shown in Figures 3 and 4, and covers the equipment 9 shown in Figures 1, 2, and 4 when the subcritical water treatment device 2 is in use, and moves along arrow A in Figure 4 to cover the subcritical water treatment device 2 when the subcritical water treatment device 2 is not in use.

[0044] The equipment 9 includes a water tank provided so that the steam supplying device 23 can supply steam, a generator for supplying power to the subcritical water treatment device 2, and the like, and is disposed close to the subcritical water treatment device 2. By providing the tent house 4, the subcritical water treatment device 2 can be protected from sea breezes even if the organic waste treatment device 1 is disposed in a location close to the sea (for example, near a power plant).

[0045] FIG. 6 is a flow chart showing an example of steps of an organic waste treatment method carried out by an organic waste treatment apparatus according to one embodiment of the present invention.

[0046] First, in step S1, the inlet 21A is opened and the object to be treated and the heavy metal treatment agent are charged into the pressure vessel 21. Step S1 is an example of a charging step. Charge of the heavy metal treatment agent into the pressure vessel 21 is an example of a heavy metal treatment agent adding step, and is carried out immediately before the object to be treated is charged into the pressure vessel 21, simultaneously with the charging of the object to be treated into the pressure vessel 21, or immediately after the object to be treated is charged into the pressure vessel 21.

[0047] Next, in step S2, steam generated in boiler 23A is supplied from steam inlet 21C to pressure vessel 21. Next, in step S3, within pressure vessel 21, rotating shaft 26A is rotated by motor 7 to heat and pressurize the material to be treated while stirring it.

[0048] The water vapor becomes subcritical water by heating and pressurizing, and the organic waste including the shells is decomposed by the subcritical water. Steps S2 and S3 are an example of a subcritical water treatment step.

[0049] The time required to heat and pressurize the object to be treated while stirring, i.e., the time required to turn the water vapor supplied to the pressure vessel 21 into subcritical water, is, for example, 1 hour and 40 minutes, and the time required to decompose the object to be treated using the water in a subcritical state is, for example, 45 minutes.

[0050] Next, in step S4, the supply of water vapor to the pressure vessel 21 is stopped, the water vapor exhaust valve 22C is opened by the water vapor exhaust valve drive device 28, and water vapor is exhausted from the water vapor exhaust ports 22A and 22B to reduce the temperature and pressure inside the pressure vessel 21. Then, the object to be treated that has been subjected to the subcritical water treatment in the pressure vessel 21 is dried. The time for drying the object to be treated that has been subjected to the subcritical water treatment in the pressure vessel 21 is, for example, 50 minutes.

[0051] Next, in step S5, the object to be treated that has been subjected to the subcritical water treatment in the pressure vessel 21 is taken out from the outlet 21B and supplied to the cooling section 3. Next, in step S6, the object to be treated that has been subjected to the subcritical water treatment is cooled in the cooling section 3, and fungi are added to suppress odors caused by changes over time in the object to be treated that has been subjected to the subcritical water treatment.

[0052] Step S6 is an example of a cooling step, and the addition of fungi to suppress odors caused by changes over time in the treatment object that has been treated with subcritical water is an example of a fungi adding step, and is performed at the start of cooling, at the end of cooling, or at any time between the start of cooling and the end of cooling. The time for cooling the treatment object that has been treated with subcritical water is, for example, 45 minutes. The treatment object that has been cooled after the subcritical water treatment contains sulfides.

[0053] According to this embodiment, fungi are added to the organic waste containing shells that has been treated with subcritical water while the organic waste containing shells that has been treated with subcritical water is being cooled in the cooling unit 3. This makes it possible to suppress the bad odor caused by the change over time of the organic waste containing shells that has been treated with subcritical water.

[0054] Furthermore, according to this embodiment, by introducing a heavy metal treatment agent into the pressure vessel 21, the organic waste containing shells that has been cooled after the subcritical water treatment can also be used as a soil conditioner.

[0055] The present invention is not limited to the above-described embodiment, and many modifications and variations are possible. For example, the organic waste treatment device 1 does not need to include the tent house 4. The amount of water vapor supplied to the pressure vessel 21 may be adjusted using factors other than the temperature and pressure of the pressure vessel 21. The organic waste treatment device 1 does not need to include the water vapor supply device 23. In this case, the water vapor supply device 23 is provided as part of the facility 9.

[0056] Furthermore, in this embodiment, it is not necessary to charge a heavy metal treatment agent into the pressure vessel 21. When a heavy metal treatment agent is not charged into the pressure vessel 21, the organic waste containing shells that has been cooled after the subcritical water treatment can be used as embankment or the like. [Explanation of symbols]

[0057] 1. Organic waste treatment equipment 2. Subcritical water treatment equipment 3 Cooling section 4. Tent House 5 Anchor bolts 6 Reducer 7 Motor 8 Rail 9 Equipment 21 Pressure Vessels 21A Inlet 21B Outlet 21C Steam inlet 21D Clutch door 21E Handle 22 Water vapor exhaust device 22A, 22B Water vapor exhaust port 22C Water vapor exhaust valve 23 Steam supply device 23A Boiler 23B Pressure Regulating Valve 24 Steam on-off valve 25 Opening and closing valve drive mechanism 26 Stirring device 26A Rotating shaft 26B Stirring blade 27 Control Device 28 Steam exhaust valve drive mechanism 30 Temperature Sensor 31 Pressure Sensor 32 Rotational speed sensor 33 Rotational torque sensor

Claims

1. An input step of inputting organic waste containing shells into a pressure vessel; a subcritical water treatment step in which water vapor is supplied to the pressure vessel, and the organic waste containing shells is heated and pressurized in the pressure vessel while being stirred, and the organic waste containing shells is decomposed using water that has been brought from a steam state to a subcritical state by the heating and pressurization; a cooling step of removing the shell-containing organic waste that has been subjected to the subcritical water treatment, which is odorless immediately after the subcritical water treatment, from the pressure vessel and cooling it; Equipped with The cooling step comprises: The organic waste treatment method includes a fungus addition step of adding fungi to the organic waste containing shells that has been subjected to the subcritical water treatment and is odorless immediately after the subcritical water treatment, the fungi being used to suppress odors caused by changes over time in the organic waste containing shells that has been subjected to the subcritical water treatment and is odorless immediately after the subcritical water treatment.

2. 2. The method for treating organic waste according to claim 1, wherein the fungi are soil bacteria.

3. 3. The method for treating organic waste according to claim 2, wherein the soil bacteria are actinomycetes.

4. The organic waste treatment method according to any one of claims 1 to 3, further comprising a heavy metal treatment agent addition step of adding a heavy metal treatment agent to the organic waste containing shells immediately before, simultaneously with, or immediately after the introduction step.

5. 5. The organic waste treatment method according to claim 4, wherein the heavy metal treatment agent is rice husk.

6. a subcritical water treatment apparatus having a pressure vessel for carrying out subcritical water treatment in which water vapor is supplied, and the organic waste containing shells is heated and pressurized while being stirred, and the organic waste containing shells is decomposed using water that has been brought from a steam state to a subcritical state by the heating and pressurization; a cooling section for cooling the organic waste containing shells that has been subjected to the subcritical water treatment and is odorless immediately after the subcritical water treatment, which is removed from the pressure vessel; Equipped with While the cooling section cools the organic waste containing shells that have been subjected to the subcritical water treatment, which is odorless immediately after the subcritical water treatment, fungi for suppressing odors caused by changes over time in the organic waste containing shells that have been subjected to the subcritical water treatment, which is odorless immediately after the subcritical water treatment, are added to the organic waste containing shells that have been subjected to the subcritical water treatment, which is odorless immediately after the subcritical water treatment.

7. The organic waste treatment device according to claim 6, wherein the fungi are soil bacteria.

8. The organic waste treatment device according to claim 7, wherein the soil bacteria are actinomycetes.

9. The organic waste treatment device according to any one of claims 6 to 8, wherein a heavy metal treatment agent is added to the organic waste containing shells immediately before the organic waste containing shells is charged into the pressure vessel, simultaneously with the charging of the organic waste containing shells into the pressure vessel, or immediately after the charging of the organic waste containing shells into the pressure vessel.

10. The organic waste treatment device according to claim 9, wherein the heavy metal treatment agent is rice husk.

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