Fertilizer manufacturing system and fertilizer manufacturing method

Abstract

To provide a fertilizer manufacturing system and a fertilizer manufacturing method that manufacture a fertilizer using incinerated ash.SOLUTION: A fertilizer manufacturing system includes: a mixing device that mixes incinerated ash and an auxiliary agent including at least phosphorus dissolving bacterial; a first measuring device that measures at least any of available form phosphoric acid, water-soluble phosphoric acid, and citrate-soluble phosphoric acid contained in the admixture of the incinerated ash and the auxiliary agent in the mixing device; and a control device that determines based on the measured result in the first measuring device whether the admixture should be discharged from the mixing device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fertilizer production system and a fertilizer production method. [Background technology]

[0002] For example, various techniques have been proposed for treating exhaust gas from incinerators that incinerate sewage sludge (hereinafter also simply referred to as sludge or material to be incinerated) (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-221206 Summary of the Invention [Problem to be solved by the invention]

[0004] The exhaust gas discharged from the incinerator as described above contains, for example, incineration ash (hereinafter simply referred to as incineration ash) generated by the incineration of the materials to be incinerated. In an incineration system having the incinerator as described above (hereinafter simply referred to as an incineration system), it is desirable to effectively utilize the incineration ash contained in the exhaust gas for other purposes. Specifically, in an incineration system as described above, it is desirable to produce fertilizer using the incineration ash contained in the exhaust gas. [Means for solving the problem]

[0005] The fertilizer production system of the present invention includes a mixing device that mixes incineration ash with an auxiliary agent containing at least phosphorus-dissolving bacteria, a first measuring device that measures at least one of available phosphate, water-soluble phosphate, and citrate-soluble phosphate contained in the mixture of the incineration ash and the auxiliary agent in the mixing device, and a control device that determines whether to discharge the mixture from the mixing device based on the measurement results of the first measuring device. [Effects of the Invention]

[0006] According to the fertilizer production system and fertilizer production method of the present invention, it is possible to produce fertilizer using incineration ash. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of an incineration system 1000 according to the first embodiment. [Figure 2] FIG. 2 is a diagram illustrating the hardware configuration of the control device 10. As shown in FIG. [Figure 3] FIG. 3 is a flowchart illustrating the fertilizer producing method according to the first embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of the configuration of an incineration system 2000 according to the second embodiment. [Figure 5] FIG. 5 is a diagram illustrating an example of the configuration of an incineration system 2000 according to the second embodiment. [Figure 6] FIG. 6 is a diagram illustrating an example of the configuration of an incineration system 3000 according to the third embodiment. [Figure 7] FIG. 7 is a flowchart illustrating a temperature adjustment method according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, such descriptions should not be interpreted in a limiting sense, and do not limit the subject matter described in the claims. Furthermore, various changes, substitutions, and modifications can be made without departing from the spirit and scope of the present disclosure. Furthermore, different embodiments can be combined as appropriate.

[0009] [Incineration system 1000 according to the first embodiment] First, an incineration system 1000 in the first embodiment will be described. Figure 1 is a diagram illustrating an example of the configuration of the incineration system 1000 in the first embodiment. Note that the arrangement positions, lengths, and numbers of pipes shown below are examples and are not limited to these.

[0010] 1, the incineration system 1000 includes, for example, a blower B1, an incinerator 1, a recovery device 2, a storage tank 3, a pump P1, a mixer 4, a pump P2, a measuring device M1 (hereinafter also referred to as the first measuring device M1), and a control device 10. Hereinafter, the storage tank 3, the pump P1, the mixer 4, the pump P2, the measuring device M1, and the control device 10 will also be collectively referred to as the fertilizer production system 100.

[0011] The blower B1 is, for example, a device that supplies air (hereinafter also referred to as combustion air) to the incinerator 1 via a line L21. The line L21 is, for example, a pipe that connects the outlet side of the blower B1 with the inlet side of the combustion air in the incinerator 1. Specifically, the blower B1 is, for example, a device that has the function of blowing air, such as a fan or a blower.

[0012] The incinerator 1 is, for example, a fluidized bed incinerator that incinerates sludge (dewatered cake) supplied via line L11, and has a so-called fluidized bed 1a. Line L11 is, for example, a pipe that connects upstream equipment of the incinerator 1 (for example, a sludge dryer) with the sludge inlet side of the incinerator 1. The following description will be given assuming that the incinerator 1 is a fluidized bed incinerator, but the incinerator 1 may be, for example, various types of incinerators other than a fluidized bed incinerator.

[0013] The recovery device 2 is, for example, disposed downstream of the incinerator 1, and recovers incineration ash contained in the exhaust gas G1 supplied from the incinerator 1 via a line L1. The line L1 is, for example, a pipe connecting the outlet side of the exhaust gas G1 in the incinerator 1 with the inlet side of the recovery device 2.

[0014] Specifically, the recovery device 2 may be, for example, a high-temperature cyclone. The recovery device 2 may separate heavy metals from the incineration ash (solid-gas separation) by volatilizing the heavy metals contained in the incineration ash at a high temperature of, for example, 800°C or higher, and recover the incineration ash from which the heavy metals have been separated. Here, heavy metals include, for example, arsenic, mercury, cadmium, and lead.

[0015] The recovery device 2 then supplies the exhaust gas G1 (the exhaust gas G1 after the incineration ash has been recovered) to downstream equipment (not shown) of the recovery device 2, for example, via a line L2. The line L2 is, for example, a pipe that connects the outlet side of the exhaust gas G1 in the recovery device 2 with the downstream equipment.

[0016] The recovery device 2 also supplies the incineration ash to the mixer 4 via, for example, a line L3. The line L3 is, for example, a pipe that connects the incineration ash outlet side of the recovery device 2 with the mixer 4.

[0017] The incineration system 1000 may include, as downstream equipment of the recovery device 2, a dust collector (not shown) that removes impurities from the exhaust gas G1 discharged from the recovery device 2, a heat exchanger (not shown) that recovers the heat contained in the exhaust gas G1, and a SO 4 removal device (not shown) that removes the SO 4 from the exhaust gas G1. X The apparatus may also have a smoke washing tower (not shown) that removes components such as those mentioned above by incorporating them into smoke washing water, and a chimney (not shown) that releases the exhaust gas G1 that has been washed in the smoke washing tower to the outside.

[0018] The storage tank 3 stores, for example, an auxiliary agent (hereinafter also referred to as a first auxiliary agent) to be added to the incineration ash collected in the collection device 2.

[0019] The first auxiliary agent is, for example, an auxiliary agent containing phosphate-dissolving bacteria (microorganisms) that convert unavailable phosphate (hereinafter simply referred to as unavailable phosphate) into available phosphate (hereinafter simply referred to as available phosphate) by producing and secreting an organic acid having a chelating effect. Specifically, the first auxiliary agent may contain, for example, a microbial material containing phosphate-dissolving bacteria. Furthermore, the first auxiliary agent may contain, for example, organic matter (soil containing organic matter) that serves as nutrients for the phosphate-dissolving bacteria.

[0020] The following description will be given assuming that the first auxiliary agent is liquid, but the present invention is not limited to this. Specifically, the first auxiliary agent may be, for example, granular or powdery. In this case, the moisture content of the first auxiliary agent may be adjusted to a predetermined range (for example, about 33% to 55%) so that microorganisms can grow.

[0021] Pump P1 is disposed, for example, on line L4, and supplies (adds) the first auxiliary agent stored in storage tank 3 to mixer 4 in an amount and at a timing designated in advance by the manager of incineration system 1000 (hereinafter also simply referred to as the manager). Line L4 is, for example, a pipe connecting storage tank 3 and mixer 4.

[0022] The following description will be given assuming that the incineration system 1000 has a pump P1, but is not limited to this. Specifically, the incineration system 1000 may have, for example, a screw conveyor as a device for supplying the first auxiliary agent to the incineration ash. The incineration system 1000 may also have, for example, a syringe-type supply device, a piston-type supply device, or a rotary-type supply device as a device for supplying the first auxiliary agent to the incineration ash.

[0023] The mixing device 4 is a device that converts non-available phosphate contained in the incineration ash into available phosphate, for example, by mixing and stirring the incineration ash supplied from the recovery device 2 via line L3 and the first auxiliary agent supplied from the storage tank 3 via line L4.

[0024] That is, the mixing device 4 converts the non-available phosphate contained in the incineration ash (phosphate tightly bound to iron, aluminum, etc.) into available phosphate (phosphate in a form that is easily absorbed by plants) using, for example, organic acids produced by the phosphate-dissolving bacteria contained in the first auxiliary agent.

[0025] Specifically, in the mixer 4, for example, non-available phosphoric acid contained in the incineration ash is converted into water-soluble phosphoric acid, and then a portion of the water-soluble phosphoric acid taken up by the microorganisms is converted into citrate-soluble phosphoric acid. Hereinafter, water-soluble phosphoric acid and citrate-soluble phosphoric acid are collectively referred to as available phosphoric acid.

[0026] This makes it possible for the fertilizer production system 100 in this embodiment to produce a fertilizer containing phosphoric acid in a required form, for example.

[0027] Specifically, when incineration ash and the first auxiliary agent are supplied to the mixer 4, the mixer 4 mixes the incineration ash and the first auxiliary agent until a time period designated in advance by the manager has elapsed. More specifically, the mixer 4 mixes the incineration ash and the first auxiliary agent by operating an agitator (not shown) such as a screw conveyor installed inside the mixer 4.

[0028] In addition, the incineration system 1000 may have a water supply device (not shown) that supplies water (a small amount of water) to the mixer 4, for example, when the first auxiliary agent is in powder form, due to the need to mix and stir the incineration ash and the first auxiliary agent.

[0029] Water-soluble phosphoric acid can also be converted to citrate-soluble phosphoric acid by combining with, for example, calcium or magnesium. Therefore, the incineration system 1000 may include, for example, a supply device (not shown) that supplies calcium or magnesium to the mixer 4.

[0030] The pump P2 is disposed, for example, on the line L5, and supplies the mixture of the incineration ash and the first auxiliary agent (hereinafter also simply referred to as the mixture) from the mixer 4 to the granulator (not shown) in the amount and at the timing designated in advance by the administrator. The line L5 is, for example, a pipe that connects the mixer 4 and the granulator.

[0031] The granulation device produces pellet-shaped fertilizer by, for example, mixing and stirring the mixture supplied from the mixer 4 via line L5 with an auxiliary agent (hereinafter also referred to as a second auxiliary agent) supplied from a storage tank (not shown), and then performing dry granulation. The second auxiliary agent is, for example, an auxiliary agent containing one or more components (e.g., nitrogen and potassium) that need to be included in the fertilizer produced in the fertilizer production system 100. Specifically, the granulation device produces pellet-shaped fertilizer having a porous structure by operating, for example, a pan-type granulator (not shown), which is a rolling granulator, or a briquette (not shown), which is a pressurized granulator.

[0032] That is, the fertilizer production system 100 in this embodiment produces fertilizer by adding, for example, a second auxiliary agent containing a fertilizer-effective component not contained in the incineration ash to the incineration ash.

[0033] This makes it possible for the fertilizer production system 100 in this embodiment to produce, for example, a fertilizer containing necessary components.

[0034] The mixture stirred and mixed in the mixing device 4 can also be used as seed culture, for example, when restarting the fertilizer production system 100 or when starting up another fertilizer production system (not shown) different from the fertilizer production system 100.

[0035] The measuring device M1 measures, for example, at least one of available phosphate, water-soluble phosphate, and citrate-soluble phosphate contained in the mixture in the mixing device 4.

[0036] Specifically, the measuring device M1 is, for example, a concentration meter that measures the concentration of at least one of available phosphoric acid, water-soluble phosphoric acid, and citrate-soluble phosphoric acid contained in the mixture in the mixing device 4.

[0037] The control device 10 performs control (hereinafter also referred to as state determination control) to determine the conversion state of non-available phosphate contained in the incineration ash into available phosphate, based on the measurement results of at least one of available phosphate, water-soluble phosphate, and citrate-soluble phosphate by the measurement device M1, for example, at a predetermined timing. The predetermined timing may be, for example, a regular timing such as once every few days.

[0038] Specifically, the control device 10 determines whether the concentration (measured by the measurement device M1) of a form of phosphate designated in advance by the administrator, for example, from available phosphate, water-soluble phosphate, or citrate-soluble phosphate (hereinafter also referred to as target phosphate) exceeds a predetermined threshold. The predetermined threshold is, for example, a value previously determined as a threshold corresponding to the target phosphate.

[0039] For example, if it is determined that the concentration of the target phosphate exceeds a predetermined threshold value, the control device 10 determines that the conversion of the unavailable phosphate contained in the incineration ash has progressed sufficiently in the mixing device 4, and controls the opening of a valve (not shown) installed in the pump P2 to discharge the mixture from the mixing device 4.

[0040] On the other hand, for example, if it is determined that the concentration of the target phosphate does not exceed a predetermined threshold, the control device 10 determines that the conversion of the unavailable phosphate contained in the incineration ash has not progressed sufficiently in the mixing device 4, and continues mixing the incineration ash with the first auxiliary agent in the mixing device 4.

[0041] That is, the fertilizer production system 100 in this embodiment can continue mixing the incineration ash and the first auxiliary until the concentration of the target phosphoric acid contained in the mixture reaches or exceeds a required concentration, for example, by periodically performing state determination control. Specifically, the fertilizer production system 100 can continue mixing the incineration ash and the first auxiliary until the concentration of the target phosphoric acid contained in the mixture reaches or exceeds a concentration specified as a fertilizer specification.

[0042] As a result, the fertilizer production system 100 in this embodiment can stably produce, for example, a fertilizer in which the concentration of the target phosphoric acid is equal to or higher than a required concentration. The configuration of the control device 10 in the first embodiment will be described below.

[0043] [Control device 10 in the first embodiment] FIG. 2 is a diagram illustrating the hardware configuration of the control device 10. As shown in FIG.

[0044] 2, the control device 10 is, for example, an electronic device having an electronic circuit. Specifically, the control device 10 is, for example, a computer device having a CPU 101 which is a processor, a memory 102, a communication device 103, and a storage medium 104. Each unit is connected to each other via, for example, a bus 105.

[0045] The storage medium 104 has, for example, a program storage area (not shown) that stores a program 110 for performing state determination control. The storage medium 104 also has, for example, an information storage area 130 that stores information used when performing state determination control. The storage medium 104 may be, for example, a hard disk drive (HDD) or a solid state drive (SSD).

[0046] The CPU 101 performs state determination control by executing a program 110 loaded into the memory 102 from the storage medium 104, for example.

[0047] The communication device 103 accesses an operation terminal (not shown) through which an administrator inputs necessary information, for example, via a network (not shown) such as the Internet.

[0048] The control device 10 may have, for example, an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). The control device 10 may also include, for example, a PIC (Peripheral Interface Controller). The state determination control may be executed, for example, by the FPGA or the ASIC.

[0049] [Fertilizer manufacturing method according to the first embodiment] Next, a description will be given of a fertilizer production method according to the first embodiment. Fig. 3 is a flow chart illustrating the fertilizer production method according to the first embodiment.

[0050] The mixer 4 mixes, for example, incineration ash with a first auxiliary agent containing at least phosphorus-dissolving bacteria (step S1 in FIG. 3).

[0051] Specifically, the mixer 4 converts the non-available phosphoric acid contained in the incineration ash into available phosphoric acid by stirring and mixing the incineration ash supplied from the recovery device 2 via line L3 with the first auxiliary agent supplied from the storage tank 3 via line L4 for a predetermined time. The predetermined time may be, for example, one day.

[0052] Then, the measuring device M1 measures, for example, at least one of available phosphate, water-soluble phosphate, and citrate-soluble phosphate contained in the mixture mixed in step S1 (step S2 in FIG. 3).

[0053] Specifically, the measurement device M1 measures the concentration of the target phosphoric acid contained in the mixture mixed in step S1, for example.

[0054] Next, the control device 10 determines whether or not to discharge the mixture mixed in step S1 from the mixer 4 based on the measurement result in step S2, for example (step S3 in FIG. 3).

[0055] Specifically, the control device 10 determines whether or not the mixture mixed in step S1 should be discharged from the mixing device 4 by determining whether or not the measurement result in step S2 satisfies a predetermined condition, for example. The predetermined condition is, for example, that the concentration of the target phosphate measured in step S2 is equal to or greater than a predetermined threshold.

[0056] As a result, for example, if it is determined that the measurement result in step S2 satisfies the predetermined condition, the pump P2 discharges the mixture mixed in step S1 from the mixer 4 (YES in step S3 in FIG. 3, step S4 in FIG. 3).

[0057] On the other hand, if it is determined that the measurement result in step S2 does not satisfy the predetermined condition, the fertilizer production system 100 performs step S1 and subsequent steps again (NO in step S3 in FIG. 3).

[0058] Specifically, for example, if the target phosphate is available phosphate, the control device 10 determines whether the concentration of available phosphate measured by the measurement device M1 is equal to or greater than a predetermined threshold (a threshold predetermined as a threshold corresponding to available phosphate). If the control device 10 determines that the concentration of available phosphate is equal to or greater than the predetermined threshold, the control device 10 controls the valve installed in the pump P2 to open, thereby discharging the mixture from the mixer 4. In this case, the control device 10 may, for example, supply the mixture from the mixer 4 to a granulator. On the other hand, if the control device 10 determines that the concentration of available phosphate is not equal to or greater than the predetermined threshold, the control device 10 repeats steps S1 and subsequent steps.

[0059] Furthermore, for example, if the target phosphate is water-soluble phosphate, the control device 10 determines whether the concentration of water-soluble phosphate measured by the measurement device M1 is equal to or greater than a predetermined threshold (a threshold previously determined as a threshold corresponding to water-soluble phosphate). Then, for example, if it is determined that the concentration of water-soluble phosphate is equal to or greater than the predetermined threshold, the control device 10 discharges the mixture in the mixer 4 by controlling the opening of a valve installed in the pump P2. Note that in this case, the control device 10 may, for example, supply the mixture in the mixer 4 to a granulator. On the other hand, for example, if it is determined that the concentration of water-soluble phosphate is not equal to or greater than the predetermined threshold, the control device 10 performs step S1 and subsequent steps again.

[0060] Furthermore, for example, when the target phosphate is citrate-soluble phosphate, the control device 10 determines whether the concentration of citrate-soluble phosphate measured by the measurement device M1 is equal to or greater than a predetermined threshold (a threshold predetermined as a threshold corresponding to citrate-soluble phosphate). If the control device 10 determines that the concentration of citrate-soluble phosphate is equal to or greater than the predetermined threshold, the control device 10 controls the valve installed in the pump P2 to open, thereby discharging the mixture from the mixer 4. In this case, the control device 10 may, for example, supply the mixture from the mixer 4 to a granulator. On the other hand, if the control device 10 determines that the concentration of citrate-soluble phosphate is not equal to or greater than the predetermined threshold, the control device 10 repeats steps S1 and subsequent steps.

[0061] As described above, the fertilizer production system 100 in this embodiment includes, for example, a mixing device 4 that mixes incineration ash with a first auxiliary agent containing at least phosphorus-dissolving bacteria, a measuring device M1 that measures at least one of available phosphate, water-soluble phosphate, and citrate-soluble phosphate contained in the mixture of incineration ash and the first auxiliary agent in the mixing device 4, and a control device 10 that determines whether or not to discharge the mixture from the mixing device 4 based on the measurement results of the measuring device M1.

[0062] Specifically, the incineration ash is, for example, incineration ash contained in the exhaust gas G1 discharged from an incinerator 1 that incinerates materials to be incinerated.

[0063] Furthermore, the measuring device M1 measures the concentration of at least one of available phosphate, water-soluble phosphate, and citrate-soluble phosphate contained in the mixture. The control device 10 then determines, for example, to discharge the mixture from the mixing device 4 if the concentration measured by the measuring device M1 is equal to or greater than a predetermined threshold, and determines not to discharge the mixture from the mixing device 4 if the concentration is less than the predetermined threshold.

[0064] Furthermore, for example, when the control device 10 determines not to discharge the mixture from the mixer 4, it repeatedly measures the concentration until the concentration becomes equal to or greater than a predetermined threshold value.

[0065] That is, the fertilizer production system 100 in this embodiment, for example, by periodically performing state determination control, can continue mixing the incineration ash and the first auxiliary agent until the concentration of the target phosphate contained in the mixture reaches or exceeds the required concentration.

[0066] As a result, the fertilizer production system 100 in this embodiment can stably produce, for example, a fertilizer in which the concentration of the target phosphoric acid is equal to or higher than the required concentration.

[0067] Note that, for example, when it is determined in step S3 that the measurement result does not satisfy a predetermined condition, the control device 10 may further supply the first auxiliary agent to the mixing device 4 before performing step S1 again.

[0068] Furthermore, in the fertilizer producing method according to the present embodiment, a manager may determine, based on the measurement result in step S2, whether or not to discharge the mixture mixed in step S1 from the mixing device 4, instead of the control device 10. Then, the manager may open or close a valve installed in the pump P2 according to the determination result.

[0069] [Incineration system 2000 according to the second embodiment] Next, an incineration system 2000 in a second embodiment will be described. Figures 4 and 5 are diagrams for explaining an example of the configuration of the incineration system 2000 in the second embodiment. Note that in Figure 4, the incinerator 1 and other components are omitted.

[0070] As shown in Figure 4, the incineration system 2000 further includes a water treatment system 20 and a pump P4 in addition to the components of the incineration system 1000 described in Figure 1 etc. Hereinafter, the fertilizer production system 100, the water treatment system 20, and the pump P4 will also be collectively referred to as the fertilizer production system 200.

[0071] The water treatment system 20 is a facility that treats water to be treated (hereinafter also simply referred to as water to be treated), such as sewage.

[0072] Specifically, as shown in FIG. 5, the water treatment system 20 includes, for example, a primary sedimentation tank 11, a sewage treatment device 12, a final sedimentation tank 13, a thickening tank 14, a thickening device 15, and a digestion tank 16.

[0073] The primary sedimentation tank 11 separates, for example, organic matter and suspended matter contained in the water to be treated by settling. The primary sedimentation tank 11 then discharges, for example, the separated organic matter and suspended matter as primary sedimentation sludge to a thickening tank 14, and discharges the water to be treated from which the organic matter and suspended matter have been separated to a wastewater treatment device 12.

[0074] The sewage treatment device 12 treats the water to be treated by biological treatment, such as a standard activated sludge process or a circulating nitrification-denitrification process. Specifically, the sewage treatment device 12 has, for example, a denitrification tank (not shown) in which anaerobic denitrifying bacteria produce nitrogen from nitrate ions (denitrification), and a nitrification tank (not shown) located downstream of the denitrification tank in which aerobic nitrifying bacteria nitrify ammonia nitrogen. The sewage treatment device 12 then discharges the water to be treated into, for example, a final sedimentation tank 13.

[0075] The final settling tank 13, for example, separates and settles sludge contained in the water to be treated discharged from the sewage treatment device 12, and discharges the separated sludge as activated sludge. The final settling tank 13 then supplies, for example, a portion of the activated sludge to the thickener 15 as excess sludge, and returns the activated sludge other than the excess sludge to the sewage treatment device 12 as returned sludge. The final settling tank 13 also discharges the water to be treated (supernatant) from which the sludge has been separated, for example, to a downstream sterilization treatment device (not shown). Thereafter, the sterilization treatment device (not shown) sterilizes the water to be treated discharged from the final settling tank 13, for example, and discharges the sterilized treated water.

[0076] The thickening tank 14 thickens, for example, the primary sludge discharged from the primary sedimentation tank 11 and supplies the thickened sludge to the digestion tank 16 .

[0077] The thickener 15 thickens excess sludge discharged from the final settling tank 13, for example, and supplies the thickened sludge to the digester 16.

[0078] The digestion tank 16 is a tank that stores, for example, anaerobic bacteria and sludge. The anaerobic bacteria in the digestion tank 16 anaerobically digest (decompose) the organic matter of the sludge, including, for example, the primary sludge supplied from the thickening tank 14 and the excess sludge supplied from the thickener 15, through a biological reaction to produce digested sludge. The anaerobic bacteria in the digestion tank 16 also produce, for example, digestion gases such as methane gas during the digestion process. The digested sludge produced in the digestion tank 16 is incinerated in the incinerator 1 as, for example, material to be incinerated. Hereinafter, the primary sludge, excess sludge, and digested sludge will be collectively referred to as simply sludge.

[0079] 4, pump P4 is disposed, for example, on line L7, and supplies a portion of the sludge discharged from water treatment system 20 to mixer 4 in an amount and at a timing designated in advance by an administrator. Line L7 is, for example, a pipe connecting water treatment system 20 and mixer 4.

[0080] Specifically, the line L7 is, for example, a pipe connecting at least one of the thickening tank 14, the thickener 15, and the digester 16 to the mixer 4. The pump P4 supplies at least one of the primary sludge supplied from the thickener 14, the excess sludge supplied from the thickener 15, and the digested sludge supplied from the digester 16 to the mixer 4.

[0081] In this case, the mixing device 4 converts the non-available phosphate contained in the incineration ash into available phosphate by mixing and stirring, for example, the incineration ash supplied from the recovery device 2 via line L3, the first auxiliary agent supplied from the storage tank 3 via line L4, and the sludge supplied from the water treatment system 20 via line L7.

[0082] Thus, in the fertilizer production system 200 of this embodiment, the incineration ash is, for example, incineration ash contained in the exhaust gas G1 discharged from the incinerator 1 that incinerates the materials to be incinerated, and the materials to be incinerated are, for example, sludge generated in the water treatment system 20 that treats the water to be treated. Then, the mixer 4 of this embodiment mixes, for example, the incineration ash, the first auxiliary agent, and the sludge.

[0083] That is, the sludge supplied from the water treatment system 20 contains, for example, organic matter that serves as nutrients for phosphorus-dissolving bacteria. Therefore, in the fertilizer production system 200, for example, by mixing the sludge supplied from the water treatment system 20 with the incineration ash and the first auxiliary agent, the organic matter contained in the sludge is also used to convert the unavailable phosphoric acid contained in the incineration ash.

[0084] As a result, the fertilizer production system 200 in this embodiment can reduce the amount of organic matter contained in the first auxiliary agent supplied from the storage tank 3 to the mixer 4, for example.

[0085] [Incineration system 3000 according to the third embodiment] Next, an incineration system 3000 in the third embodiment will be described. Figure 6 is a diagram illustrating an example of the configuration of the incineration system 3000 in the third embodiment. Note that in Figure 6, the incinerator 1 and other components are omitted.

[0086] As shown in Figure 6, in addition to the components of the incineration system 1000 described in Figure 1 and elsewhere, the incineration system 3000 further includes a water treatment system 20, a pump P11 (hereinafter also referred to as the supply device P11), a heat exchanger 30, a pump P12 (hereinafter also referred to as the supply device P12), and a measuring device M2 (hereinafter also referred to as the second measuring device M2). Hereinafter, the water treatment system 20, the pump P11, the heat exchanger 30, and the pump P12 will also be collectively referred to as a temperature adjustment system 40. Hereinafter, the fertilizer production system 100, the water treatment system 20, the pump P11, the heat exchanger 30, and the pump P12 will also be collectively referred to as a fertilizer production system 300.

[0087] The pump P11 is disposed, for example, in the line L8, and circulates the treated water that has been treated in the water treatment system 20 between the water treatment system 20 and the mixer 4 in accordance with the amount and timing previously designated by the administrator. The line L8 is, for example, a circulation pipe that connects the water treatment system 20 and the mixer 4.

[0088] The heat exchanger 30 is, for example, a heat exchanger that is installed on the line L1 described in Fig. 1 etc. and recovers thermal energy of the exhaust gas G1 discharged from the incinerator 1. The heat exchanger 30 then raises the temperature of a heat medium (not shown) by using the recovered thermal energy, for example.

[0089] The pump P12 is disposed, for example, on the line L9, and circulates the heat medium heated in the heat exchanger 30 between the heat exchanger 30 and the mixer 4 in accordance with the amount and timing previously designated by the administrator. The line L9 is, for example, a circulation pipe that connects the heat exchanger 30 and the mixer 4.

[0090] The measuring device M2 is, for example, a thermometer that measures the temperature of the mixture in the mixer 4 (the mixture being mixed in the mixer 4).

[0091] In addition to state determination control, the control device 10 performs a process of adjusting the temperature inside the mixing device 4 (hereinafter also referred to as temperature adjustment control) by, for example, controlling the opening or closing of at least one of a valve (not shown) installed in pump P11 and a valve (not shown) installed in pump P12 based on the measurement results by the measurement device M2.

[0092] Specifically, for example, when the temperature measured by the measuring device M2 exceeds a predetermined upper threshold (hereinafter simply referred to as the upper threshold), the control device 10 controls the opening of a valve installed in the pump P11, thereby supplying treated water from the water treatment system 20 to the mixer 4. The upper threshold is, for example, the upper limit of the temperature suitable for converting unavailable phosphate contained in the mixture in the mixer 4. In this case, the mixer 4 cools the mixture in the mixer 4 by using, for example, the treated water supplied from the water treatment system 20 as cooling water.

[0093] Thereafter, for example, if the temperature measured by the measuring device M2 falls below the upper threshold, the control device 10 stops the supply of treated water from the water treatment system 20 to the mixing device 4 by controlling the valve installed in the pump P11 to close.

[0094] Furthermore, for example, when the temperature measured by the measuring device M2 is below a predetermined lower threshold (hereinafter also referred to as the lower threshold), the control device 10 starts recovering thermal energy from the exhaust gas G1 using the heat exchanger 30 and controls the opening of a valve installed in the pump P12, thereby supplying a heat transfer medium from the heat exchanger 30 to the mixer 4. The lower threshold is, for example, the lower limit of the temperature suitable for converting unavailable phosphoric acid contained in the mixture in the mixer 4. In this case, the mixer 4 increases the temperature of the mixture in the mixer 4 using, for example, the heat transfer medium supplied from the heat exchanger 30.

[0095] Thereafter, for example, when the temperature measured by the measuring device M2 becomes equal to or higher than the lower threshold, the control device 10 stops the supply of heat medium from the heat exchanger 30 to the mixing device 4 by controlling the valve installed in the pump P12 to close.

[0096] In the following, a case where the control device 10 performs both the state determination control and the temperature adjustment control will be described, but the present invention is not limited to this. Specifically, the temperature adjustment control may be performed by a control device other than the control device 10, for example.

[0097] [Temperature Adjustment Method in Third Embodiment] Next, a temperature adjustment method according to the third embodiment will be described below with reference to Fig. 7, which is a flow chart illustrating the temperature adjustment method according to the third embodiment.

[0098] The measuring device M2 measures, for example, the temperature of the mixture in the mixing device 4 (step S11 in FIG. 7).

[0099] Then, the control device 10 adjusts the temperature inside the mixer 4 based on the measurement result in step S11, for example (step S12 in FIG. 7).

[0100] Specifically, for example, if the temperature measured in step S11 (the temperature measured by the measuring device M2) is above the upper threshold, the control device 10 lowers the temperature inside the mixer 4 by using treated water supplied from the water treatment system 20. On the other hand, for example, if the temperature measured in step S11 (the temperature measured by the measuring device M2) is below the lower threshold, the control device 10 raises the temperature inside the mixer 4 by using the heat medium supplied from the heat exchanger 30.

[0101] As described above, the fertilizer production system 300 in this embodiment includes, for example, a measuring device M2 that measures the temperature of the mixture in the mixer 4, and a temperature adjustment system 40 that adjusts the temperature in the mixer 4 based on the measurement results of the measuring device M2. In the fertilizer production system 300 in this embodiment, the incineration ash is, for example, incineration ash contained in the exhaust gas G1 discharged from the incinerator 1 that incinerates the materials to be incinerated, and the temperature adjustment system 40 includes, for example, a pump P11 that heats the mixture in the mixer 4 by supplying a heat medium that has been heated using thermal energy recovered from the exhaust gas G1.

[0102] Furthermore, in the fertilizer production system 300 of this embodiment, the material to be incinerated is, for example, sludge generated in the water treatment system 20 that treats the water to be treated, and the temperature adjustment system 40 has, for example, a pump P12 that cools the mixture in the mixing device 4 by supplying treated water that has been treated in the water treatment system 20.

[0103] This enables the fertilizer production system 300 in the present embodiment to stably convert, for example, non-available phosphoric acid contained in the mixture in the mixer 4. Specifically, the fertilizer production system 300 can stably convert, for example, non-available phosphoric acid contained in the mixture in the mixer 4 even when the temperature inside the mixer 4 fluctuates due to seasonal changes or the like. [Explanation of symbols]

[0104] 1: Incinerator 1a: Fluidized bed 2: Recovery device 3: Storage tank 4: Mixing device 5: Storage tank 10: Control device 11: Primary sedimentation tank 12: Sewage treatment equipment 13: Final sedimentation tank 14: Concentrator tank 15: Concentrator 16: Digestion tank 20: Water treatment system 30: Heat exchanger 40: Temperature control system 100: Fertilizer production system 101: CPU 102: Memory 103: Communication device 104: Storage medium 105: Bus 200: Fertilizer production system 300: Fertilizer production system 1000: Incineration system 2000: Incineration system 3000: Incineration system B1: Blower L1: Line L2: Line L3: Line L4: Line L5: Line L7: Line L8: Line L9: Line L11: Line L21: Line M1: Measuring device M2: Measuring device P1: Pump P2: Pump P4: Pump P11: Pump P12: Pump

Claims

1. A mixing device for mixing incineration ash with an auxiliary agent containing at least phosphorus-dissolving bacteria; A first measuring device for measuring at least one of available phosphoric acid, water-soluble phosphoric acid, and citrate-soluble phosphoric acid contained in the mixture of the incineration ash and the auxiliary agent in the mixing device; a control device that determines whether or not to discharge the mixture from the mixing device based on the measurement result of the first measuring device.

2. a second measuring device for measuring the temperature of the mixture in the mixing device; The fertilizer production system according to claim 1 , further comprising: a temperature adjustment system that adjusts the temperature in the mixing device based on the measurement result in the second measurement device.

3. The incineration ash is incineration ash contained in exhaust gas discharged from an incinerator that incinerates materials to be incinerated, 3. The fertilizer production system according to claim 2, wherein the temperature adjustment system includes a supply device that supplies a heat medium heated by using thermal energy recovered from the exhaust gas to heat the mixture in the mixing device.

4. The incineration ash is incineration ash contained in exhaust gas discharged from an incinerator that incinerates materials to be incinerated, The material to be incinerated is sludge generated in a water treatment system that treats water to be treated, 3. The fertilizer production system according to claim 2, wherein the temperature adjustment system includes a supply device that cools the mixture in the mixing device by supplying treated water that has been treated in the water treatment system.

5. The incineration ash is incineration ash contained in exhaust gas discharged from an incinerator that incinerates materials to be incinerated, The material to be incinerated is sludge generated in a water treatment system that treats water to be treated, The fertilizer production system according to claim 1 , wherein the mixing device mixes the incineration ash, the auxiliary agent, and the sludge.

6. A fertilizer production method for a fertilizer production system equipped with a mixer that mixes incineration ash with an auxiliary agent containing at least phosphorus-dissolving bacteria, A mixing step of mixing the incineration ash and the auxiliary; A first measurement step of measuring at least one of available phosphoric acid, water-soluble phosphoric acid, and citrate-soluble phosphoric acid contained in the mixture of the incineration ash and the auxiliary in the mixing step; a determination step of determining whether or not to discharge the mixture from the mixing device based on the measurement result in the first measurement step.

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