Fermentation apparatus

Abstract

To provide a fermentation apparatus that is capable of promoting fermentation of water to be treated without obstructing the separation of sludge and the water to be treated.SOLUTION: A fermentation apparatus 1 is configured to ferment organic matter in water to be treated W by bringing the water to be treated W into contact with sludge containing microorganisms. The fermentation apparatus 1 comprises: a fermentation tank 11; a partition plate 13 that partitions an internal space 12 of the fermentation tank 11 into an upper space 121 and a lower space 122; a plurality of microbial carriers 14 disposed in the upper space 121 and configured to support sludge; a to-be-treated water spraying part 15 that sprays the water to be treated W onto the microbial carriers 14; and a to-be-treated water discharge part 2 that discharges the water to be treated W stored in the lower space 122 to the outside of the fermentation apparatus 1. The fermentation apparatus 1 is also configured to enable the application of an electric current to the sludge stored in the lower space 122.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fermentation apparatus. [Background technology]

[0002] Conventionally, fermentation by microorganisms has been used for the purpose of removing organic matter from water to be treated that contains organic matter, recovering resources, etc. As a method for efficiently performing water treatment using microorganisms, the Down-flow Hanging Sponge (DHS) method is known, in which the water to be treated is sprayed onto a microbial carrier carrying sludge containing microorganisms, and the water to be treated is fermented by the microorganisms in the sludge while the water to be treated is permeated by gravity.

[0003] For example, Patent Document 1 describes a sprinkler-type purification device in which a treatment space is formed within a hollow tank, a sprinkler section is provided, and microbial carriers are filled and arranged below the sprinkler section. The device is equipped with a treated water supply means for supplying treated water from the sprinkler section to the microbial carriers, a treated water discharge means for extracting treated water purified by the microbial carriers, an air supply pipe for supplying oxygen-containing gas into the treatment space, and an exhaust pipe for discharging gas from within the treatment space.

[0004] In the DHS method, the sludge attached to the microbial carrier falls downward together with the treated water. In order to separate this sludge from the fermented treated water, a settling tank for settling the sludge is sometimes provided below the tank. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-179517 A Summary of the Invention [Problem to be solved by the invention]

[0006] The sludge that flows into the settling tank together with the water to be treated contains microorganisms. Because these microorganisms are not inactivated, the water to be treated is fermented by the microorganisms in the sludge even in the settling tank. Therefore, if the fermentation of the water to be treated in the settling tank can be promoted, the fermentation efficiency of the water to be treated in the entire fermentation apparatus can be expected to improve.

[0007] However, in the settling tank, the flow of the water to be treated in the settling tank needs to be as gentle as possible in order to settle the sludge, which makes it difficult to bring the sludge and the water to be treated into sufficient contact in the settling tank, and this limits the promotion of fermentation of the water to be treated in the settling tank.

[0008] The present invention has been made in consideration of the above problems, and aims to provide a fermentation apparatus that can promote the fermentation of the water to be treated without impeding the separation of sludge and the water to be treated. [Means for solving the problem]

[0009] One aspect of the present invention is a fermentation apparatus configured to ferment organic matter in the water to be treated by contacting the water to be treated with sludge containing microorganisms, A fermentation tank; A partition plate disposed in the fermenter and dividing the internal space of the fermenter into an upper space and a lower space; A plurality of microbial carriers arranged in the upper space of the fermenter and configured to be capable of carrying the sludge; A water-to-be-treated spraying unit that sprays the water to be treated onto the microorganism carrier; a treated water discharge section that is provided with a treated water discharge pipe that opens into the lower space and discharges the treated water stored in the lower space to the outside of the fermentation apparatus; The fermentation apparatus is configured so that an electric current can be applied to the sludge stored in the lower space. Effect of the Invention

[0010] The fermentation apparatus is configured to be able to pass an electric current through the sludge stored in the lower space of the fermentation tank. When an electric current is passed through the sludge stored in the lower space, electrons are supplied to the microorganisms in the sludge. This makes it possible to promote fermentation of organic matter. Furthermore, the fermentation apparatus is able to pass an electric current through the sludge while the sludge is allowed to settle in the lower space. Therefore, the fermentation apparatus can promote fermentation of the water to be treated without impeding separation of the sludge stored in the lower space of the fermentation tank from the water to be treated.

[0011] As described above, according to the above-mentioned embodiment, it is possible to provide a fermentation apparatus capable of promoting fermentation of the water to be treated without impeding separation of the sludge and the water to be treated. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view showing a main part of a fermentation apparatus in the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing a main part of a fermentation apparatus equipped with a partition wall in the second embodiment. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a cross-sectional view showing a main part of a fermentation apparatus equipped with plate-shaped electrodes in the third embodiment. [Diagram 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a plan view showing an example of the second electrode in the third embodiment. [Figure 7] FIG. 7 is a cross-sectional view showing a main part of a fermentation apparatus having a first electrode provided with a through-hole in the fourth embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing a main part of a fermentation apparatus having a plurality of electrode pairs in the fifth embodiment. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. [Figure 10] FIG. 10 is a cross-sectional view showing a main part of a fermentation apparatus having the insulator between a pair of electrodes in the sixth embodiment. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] (Embodiment 1) An embodiment of the fermentation apparatus will be described with reference to FIG. 1. The fermentation apparatus 1 of this embodiment is configured to ferment organic matter in the water W to be treated by contacting the water W with sludge containing microorganisms. As shown in FIG. 1, the fermentation apparatus 1 includes a fermentation tank 11, a partition plate 13 arranged in the fermentation tank 11 and dividing the internal space 12 of the fermentation tank 11 into an upper space 121 and a lower space 122, a plurality of microorganism carriers 14 arranged in the upper space 121 of the fermentation tank 11 and configured to be able to support sludge, a water to be treated spraying section 15 that sprays the water W to be treated on the microorganism carriers 14, and a water to be treated discharge section 2 that includes a water to be treated discharge pipe 21 that opens into the lower space 122 of the fermentation tank 11 and discharges the water to be treated W stored in the lower space 122 of the fermentation tank 11 to the outside of the fermentation apparatus 1. The fermentation apparatus 1 is also configured to be able to pass an electric current through the sludge stored in the lower space 122 of the fermentation tank 11.

[0014] The water to be treated W used in the fermentation apparatus 1 is not particularly limited, and any water to be treated W containing desired organic matter can be used. As the water to be treated W, for example, wastewater containing organic waste such as sewage sludge and food waste can be used. In addition, as the water to be treated W, for example, industrial wastewater containing organic matter such as waste water-soluble coolant recovered from a processing device that performs machining can also be used.

[0015] Various shapes and sizes may be used for the fermentation tank 11. For example, the shape of the fermentation tank 11 in the fermentation apparatus 1 of this embodiment is a cylinder with a diameter of 2 m. The height of the fermentation tank 11 is 2 m.

[0016] The fermenter 11 is provided with a partition plate 13 that divides the internal space 12 into an upper space 121 and a lower space 122. The partition plate 13 is configured to allow the water W to be treated and sludge to flow therethrough.

[0017] The microorganism carrier 14 is placed on the partition plate 13 in the upper space 121 of the fermenter 11. For example, a porous body such as a resin sponge, a cylindrical body such as a plastic molded into a cylindrical shape, a framed porous body in which a plastic frame is provided around the porous body, etc. can be used as the microorganism carrier 14. Specifically, the microorganism carrier 14 in this embodiment is a framed porous body in which a plastic frame is provided around a resin sponge.

[0018] Sludge containing microorganisms is supported on the microorganism carrier 14. The microorganisms in the sludge may be appropriately selected depending on the type of organic matter in the water to be treated W and the desired mode of fermentation. For example, when attempting to produce biogas containing methane by fermenting the organic matter in the water to be treated, sludge containing methanogens may be supported on the microorganism carrier 14.

[0019] The treated water spraying section 15 is configured to be able to spray the treated water W to the microorganism carrier 14. The specific form of the treated water spraying section 15 is not particularly limited, and various forms are possible. For example, the treated water spraying section 15 may be arranged along the side surface in the upper space 121 of the fermenter 11 and configured to spray the treated water W from the side of the microorganism carrier 14. The treated water spraying section 15 may also be arranged above the microorganism carrier 14 and configured to spray the treated water W from above the microorganism carrier 14. From the viewpoint of more easily spraying the treated water W over the entire microorganism carrier 14 in the fermenter 11, it is preferable that the treated water spraying section 15 is arranged above the microorganism carrier 14.

[0020] As the treated water spraying section 15, for example, a spray nozzle configured to be able to spray the treated water W into the fermenter 11, or a spray pipe having small holes for releasing the treated water W, etc. can be used.

[0021] The supply path of the water to be treated W from the outside of the fermentation apparatus 1 to the water to be treated spraying section 15 may take various forms. For example, the water to be treated spraying section 15 in this embodiment is configured to directly spray the water to be treated W supplied from the outside of the fermentation apparatus 1.

[0022] The fermentation apparatus 1 may have a treated water circulation section 4 that includes a treated water circulation pipe 41 that opens into the lower space 122 of the fermentation tank 11 and a treated water circulation pump 42 that is provided on the path of the treated water circulation pipe 41, and sends the treated water W stored in the lower space 122 of the fermentation tank 11 to the treated water spray section 15. In this case, the treated water spray section 15 can spray the treated water W stored in the lower space 122 onto the microorganism carrier 14. The treated water W stored in the lower space 122 may contain organic matter that was not consumed by the microorganisms during the process of flowing through the fermentation tank 11. Even in such a case, the treated water W in the lower space 122 is supplied to the treated water spray section 15 by the treated water circulation section 4, and is sprayed again from the treated water spray section 15 onto the microorganism carrier 14, thereby further reducing the amount of organic matter in the treated water W.

[0023] The treated water circulation pipe 41 in the treated water circulation unit 4 of this embodiment protrudes from the side surface of the fermenter 11 and opens into the lower space 122. The treated water circulation pipe 41 also connects the lower space 122 of the fermenter 11 to the treated water spray unit 15. The treated water circulation pump 42 is configured to suck up the treated water W stored in the lower space 122 and supply it to the treated water spray unit 15 via the treated water circulation pipe 41.

[0024] The fermenter 11 may be provided with a gas outlet 16 that leads gas generated by fermentation of the water to be treated W to the outside of the fermenter 11. For example, the gas outlet 16 in this embodiment is provided at the upper end of the fermenter 11. The gas led out from the gas outlet 16 is used for various purposes depending on its composition. For example, biogas containing methane gas is used as fuel for generators, etc. Furthermore, methane gas refined from biogas may be used as a raw material for C1 chemistry.

[0025] The water to be treated W and sludge that flow down from the upper space 121 of the fermenter 11 pass through the partition plate 13 and are stored in the lower space 122 of the fermenter 11. Of the water to be treated W and sludge that fall into the lower space 122, the sludge, which has a relatively high specific gravity, settles as a sludge layer M at the bottom of the fermenter 11. The water to be treated W, which has a lower specific gravity than the sludge, becomes the supernatant of the sludge layer M and is separated from the sludge.

[0026] The lower space 122 is provided with a treated water discharge pipe 21 that opens into the lower space 122, and is provided with a treated water discharge section 2 that discharges the treated water W stored in the lower space 122 to the outside of the fermentation apparatus 1. The specific form of the treated water discharge section 2 is not particularly limited, and various forms are possible. For example, the treated water discharge pipe 21 in the treated water discharge section 2 of this embodiment protrudes from the side surface of the fermentation tank 11 into the lower space 122 and opens into the lower space 122. The treated water discharge pipe 21 is configured to extract the treated water W stored above the sludge layer M from the lower space 122 of the fermentation tank 11 and lead it to the outside of the fermentation apparatus 1.

[0027] The lower space 122 of the fermenter 11 may be provided with a sludge discharge section 5 for discharging sludge stored in the lower space 122. In this case, the amount of sludge stored in the lower space 122 can be easily adjusted. The specific embodiment of the sludge discharge section 5 is not particularly limited, and various embodiments are possible. For example, the sludge discharge section 5 in this embodiment has a sludge discharge pipe 51 that opens at the bottom of the fermenter 11. The sludge discharge pipe 51 is configured to be able to extract sludge that has settled at the bottom of the fermenter 11 and lead it to the outside of the fermentation apparatus 1.

[0028] The fermentation apparatus 1 may have a sludge spreading section 6 arranged above the microorganism carrier 14, which spreads sludge onto the microorganism carrier 14, and a sludge circulation section 61 arranged in the lower space 122, which sends the sludge in the lower space 122 to the sludge spreading section 6. As described above, the microorganisms contained in the sludge in the lower space 122 may maintain the ability to ferment organic matter. Therefore, by supplying the sludge stored in the lower space 122 to the sludge spreading section 6 by the sludge circulation section 61 and spreading it from the sludge spreading section 6 onto the microorganism carrier 14, the microorganisms are replenished to the microorganism carrier 14, and the fermentation efficiency of the entire fermentation apparatus 1 can be more easily maintained.

[0029] The specific aspects of the sludge sprinkling section 6 and the sludge circulating section 61 are not particularly limited. For example, the sludge sprinkling section 6 can be a sprinkling nozzle configured to be able to sprinkle sludge into the upper space 121 of the fermenter 11, or a sprinkling pipe with small holes for discharging sludge. The sludge circulating section 61 of this embodiment has a sludge circulation pipe 611 that connects the lower space 122 of the fermenter 11 and the sludge sprinkling section 6, and a sludge pump 612 provided on the path of the sludge circulation pipe 611. The sludge circulation pipe 611 protrudes from the bottom surface of the fermenter 11 into the lower space 122 and opens into the lower space 122. The sludge pump 612 is configured to suck up sludge from the sludge layer M in the lower space 122 and supply it to the sludge sprinkling section 6 via the sludge circulation pipe 611.

[0030] The fermentation apparatus 1 is configured to be able to pass an electric current through the sludge stored in the lower space 122 of the fermenter 11. As described above, the sludge that flows into the lower space 122 together with the water to be treated W contains microorganisms. These microorganisms are not inactivated and may have the ability to ferment organic matter in the water to be treated W. Therefore, by passing an electric current through the sludge stored in the lower space 122, it is possible to promote the fermentation of the water to be treated W by the microorganisms in the sludge. From the viewpoint of more reliably obtaining the effect of promoting the fermentation of the water to be treated W by the microorganisms, it is preferable that the electric current passed through the sludge is a direct current. Furthermore, from the viewpoint of avoiding electrolysis of the water to be treated W, it is preferable that the voltage applied to pass an electric current is 3 V or less.

[0031] From the standpoint of more reliably achieving the effect of promoting fermentation in the lower space 122, it is preferable that the microorganisms in the sludge include organic matter assimilation bacteria that have the property of fermenting organic matter in the water to be treated W, and electron-emitting bacteria that have the property of transferring electrons received from outside to the organic matter assimilation bacteria. In this case, electrons can be supplied to the electron-emitting bacteria by passing an electric current through the sludge stored in the lower space 122 via the electrode 3 or the like. Furthermore, the electron-emitting bacteria that have received electrons can transfer the electrons to the organic matter assimilation bacteria, thereby promoting the fermentation of the organic matter in the lower space 122.

[0032] The type of organic matter assimilation bacteria is not particularly limited. For example, the microorganisms in the fermentation apparatus 1 of this embodiment include methanogens as organic matter assimilation bacteria, and are configured to ferment organic matter in the water to be treated W and generate biogas containing methane. Examples of methanogens include Methanobacterium and Methanosarcina.

[0033] Electron-emitting bacteria have the property of receiving electrons from the outside and transferring them to organic matter-utilizing bacteria. Examples of microorganisms having this property include Morganella morganii and Proteus mirabilis.

[0034] The method of passing a current through the sludge is not particularly limited and may take various forms. For example, the fermentation apparatus 1 may be configured to apply a voltage to members facing the lower space 122, such as the wall surface of the fermentation tank 11, the untreated water discharge pipe 21, the untreated water circulation pipe 41, the sludge discharge pipe 51, and the sludge circulation pipe 611, so that a current can be passed through a current path including these members and the sludge.

[0035] The fermentation apparatus 1 may have an electrode 3 for passing a current through the sludge, and may be configured to pass a current through a current path including the electrode 3 and the sludge. The number of electrodes 3 provided in the fermentation apparatus 1 may be one, or may be two or more. When the fermentation apparatus 1 is provided with one electrode 3, for example, a potential difference may be formed between the electrode 3 and a member facing the lower space 122 described above, so that a current can be passed through a current path including the member, the electrode 3, and the sludge. When the fermentation apparatus 1 is provided with two or more electrodes 3, for example, a potential difference may be formed between these electrodes 3, so that a current can be passed through a current path including multiple electrodes 3 and the sludge.

[0036] The shape and number of the electrodes 3 are not particularly limited and may take various forms. For example, the shape of the electrodes 3 may be various forms such as a plate, a rod, or a mesh. The electrodes 3 may be provided on the side or bottom surface of the fermenter 11 as long as they are in a position that contacts the sludge. The electrodes 3 may also have a function other than the function of passing an electric current through the sludge, such as a function of adjusting the flow of the water W to be treated and the sludge in the lower space 122.

[0037] The fermentation apparatus 1 of this embodiment has a plurality of electrodes 3 for passing a current through the sludge in the lower space 122 of the fermentation tank 11. These electrodes 3 are erected on the bottom of the fermentation tank 11, and one electrode 3 is spaced apart from the other electrode 3. The fermentation apparatus 1 of this embodiment can pass a current through the sludge layer M that has settled in the lower space 122 by applying a voltage between the electrodes 3 so that one of the two electrodes 3 is a positive electrode and the other is a negative electrode.

[0038] Next, an example of the operation of the fermentation apparatus 1 of this embodiment will be described. When operating the fermentation apparatus 1 of this embodiment, the water W to be treated is sprayed from the water to be treated spraying section 15 into the fermentation tank 11. The water W to be treated flows downward while contacting the surface and the inside of the microorganism carriers 14. At this time, the sludge carried by the microorganism carriers 14 comes into contact with the water W to be treated, and the organic matter in the water W to be treated is fermented by the microorganisms in the sludge. In addition, a part of the sludge attached to the microorganism carriers 14 falls off from the microorganism carriers 14 due to the flow of the water W to be treated, and flows downward together with the water W to be treated.

[0039] The water W to be treated and the sludge that have flowed down the upper space 121 of the fermenter 11 pass through the partition plate 13 and flow into the lower space 122. The water W to be treated and the sludge that have flowed into the lower space 122 are separated due to the difference in specific gravity. As a result, a sludge layer M consisting of the sludge that has settled at the bottom of the fermenter 11 is formed, and the water W to be treated floats up on the sludge layer M. The water W to be treated stored in the lower space 122 is discharged from the microorganism carrier 14 to the outside of the fermentation apparatus 1 as necessary, or is sent to the water to be treated spraying section 15 by the water to be treated circulating section 4. The water to be treated W sent to the water to be treated spraying section 15 by the water to be treated circulating section 4 is sprayed again from the water to be treated spraying section 15 to the microorganism carrier 14.

[0040] Similarly, the sludge stored in the lower space 122 is discharged from the sludge discharge section 5 to the outside of the fermentation apparatus 1 as necessary, or sent to the sludge spreading section 6 by the sludge circulation section 61. Moreover, the sludge sent to the sludge spreading section 6 by the sludge circulation section 61 is again spread from the sludge spreading section 6 onto the microorganism carriers 14. This allows the amount of the water W to be treated and the amount of sludge stored in the lower space 122 to be adjusted.

[0041] Furthermore, by applying a voltage between the electrodes 3 provided in the lower space 122 of the fermenter 11, a current is passed through the sludge present between the electrodes 3, and electrons can be supplied to the electron-emitting bacteria present between the electrodes 3. The electron-emitting bacteria that receive electrons in this way transfer the electrons to the organic matter assimilation bacteria present in their vicinity. The organic matter assimilation bacteria that receive electrons can then efficiently ferment the organic matter in the water W to be treated.

[0042] As described above, the fermentation apparatus 1 of this embodiment can promote fermentation of organic matter through interaction between the electron-emitting bacteria and the organic matter assimilation bacteria in the lower space 122 of the fermenter 11, without impeding separation of the water W to be treated and the sludge stored in the lower space 122 of the fermenter 11. As a result, the fermentation of the water W to be treated can be promoted without impeding separation of the sludge and the water W to be treated.

[0043] (Embodiment 2) In this embodiment, an example of a fermentation apparatus 102 in which the water to be treated W is supplied to the lower space 122 of the fermenter 11 from outside the fermentation apparatus 102 will be described. Note that, among the symbols used in the second and subsequent embodiments, the same symbols as those used in the previous embodiments represent the same components, etc. as those in the previous embodiments, unless otherwise specified.

[0044] As shown in Fig. 2, the fermentation apparatus 102 of this embodiment has a fermentation tank 11 and a partition plate 13 that divides the internal space 12 of the fermentation tank 11 into an upper space 121 and a lower space 122. The upper space 121 of the fermentation tank 11 is provided with a microorganism carrier 14 placed on the partition plate 13, and a treated water spraying section 15 and a sludge spraying section 6 arranged above the microorganism carrier 14. A gas outlet section 16 is provided at the upper end of the fermentation tank 11. A treated water discharge pipe 21 of the treated water discharge section 2 opens into a side surface of the lower space 122 of the fermentation tank 11. A plurality of electrodes 3 and a sludge discharge pipe 51 of the sludge discharge section 5 are provided at the bottom of the fermentation tank 11.

[0045] Furthermore, the fermentation apparatus 102 of this embodiment has a treated water circulating section 4 that sends the treated water W stored in the lower space 122 of the fermenter 11 to the treated water spraying section 15, and a sludge circulating section 61 that sends the sludge stored in the lower space 122 to the sludge spraying section 6. The treated water circulating section 4 has a treated water circulating piping 41 and a treated water circulating pump 42. Furthermore, the sludge circulating section 61 has a sludge circulating piping 611 and a sludge pump 612. The configurations of these parts in the fermentation apparatus 102 of this embodiment are the same as those of the fermentation apparatus 1 of embodiment 1.

[0046] The fermentation apparatus 102 of this embodiment also has a treated water supply pipe 71 that opens into the lower space 122, and has a treated water supply section 7 that supplies the treated water W to the lower space 122 of the fermentation tank 11 from outside the fermentation apparatus 102. More specifically, the treated water supply pipe 71 in the treated water supply section 7 of this embodiment protrudes from above the treated water circulation piping 41 on the side surface of the fermentation tank 11 into the lower space 122 and opens into the lower space 122.

[0047] The untreated water supply section 7 is configured to be able to supply the untreated water W from the untreated water supply pipe 71 to the lower space 122. The untreated water W flowing from the untreated water supply pipe 71 into the lower space 122 is sent to the untreated water spraying section 15 through the untreated water circulating piping 41. Then, the untreated water W that has reached the untreated water spraying section 15 is sprayed from the untreated water spraying section 15 to the microorganism carriers 14.

[0048] 2 and 3, the fermentation apparatus 102 of this embodiment has a partition wall 17 that divides the lower space 122 of the fermenter 11 into a first portion 122a and a second portion 122b. Of the two portions 122a and 122b of the lower space 122 divided by the partition wall 17, an opening of the treated water circulation pipe 41, an opening of the treated water supply pipe 71, and an opening of the sludge circulation pipe 611 are arranged in the first portion 122a. Moreover, an opening of the treated water discharge pipe 21, an opening of the sludge discharge pipe 51, and two electrodes 3 are arranged in the second portion 122b of the lower space 122.

[0049] The partition wall 17 is configured to be able to block the flow of the water to be treated W flowing in from the water to be treated supply unit 7. The arrangement and shape of the partition wall 17 may take various forms. For example, the partition wall 17 in this embodiment is flat and has no through-holes. As shown in FIG. 2, the partition wall 17 is erected upward from the bottom of the fermenter 11 and faces the opening of the water to be treated circulation pipe 41 and the opening of the water to be treated supply pipe 71. As shown in FIG. 3, the partition wall 17 is arranged so that its plate surface is perpendicular to the central axis of the water to be treated supply pipe 71. A gap is provided between the partition wall 17 and the side wall of the fermenter 11, and the water to be treated W and sludge can pass through the gap between the partition wall 17 and the side wall of the fermenter 11.

[0050] From the viewpoint of making it easier for the treated water W flowing in from the treated water supply section 7 to remain in the first portion 122a of the lower space 122, it is preferable that the partition section 17 is positioned at a position where the distance from the partition section 17 to the treated water circulation pipe 41 is shorter than the distance from the partition section 17 to the treated water discharge pipe 21.

[0051] In the fermentation apparatus 102 of this embodiment, by providing a partition portion 17 in the lower space 122 of the fermentation tank 11, the lower space 122 can be divided into two portions, a first portion 122a and a second portion 122b, by the partition portion 17, as shown in Figure 3.

[0052] The water to be treated W, which is relatively rich in organic matter and is supplied from the water to be treated supply pipe 71, flows into the first portion 122a of the lower space 122. In addition, since the partition wall portion 17 faces the opening of the water to be treated supply pipe 71, the flow of the water to be treated W that flows in from the water to be treated supply pipe 71 is blocked by the partition wall portion 17. As a result, the water to be treated W, which is relatively rich in organic matter and that flows in from the water to be treated supply pipe 71, tends to remain in the first portion 122a of the lower space 122.

[0053] Furthermore, by dividing the first portion 122a and the second portion 122b by the partition wall 17, the water W to be treated present in the second portion 122b is less likely to flow into the first portion 122a. Since the second portion 122b of the lower space 122 mainly stores the water W to be treated that has been fermented in the upper space 121 and the water W to be treated whose fermentation has been promoted in the lower space 122, the concentration of organic matter in the water W to be treated present in the second portion 122b is likely to be lower than the concentration of organic matter in the water W to be treated present in the first portion 122a. Therefore, by dividing the first portion 122a and the second portion 122b by the partition wall 17, the water W to be treated present in the first portion 122a is less likely to be diluted by the water to be treated present in the second portion 122b.

[0054] As a result of the above, water to be treated having a higher concentration of organic matter than the water to be treated W present in the second portion 122b remains in the first portion 122a of the lower space 122. Therefore, by arranging the water to be treated circulation pipe 41 in the first portion 122a, the water to be treated W present in the first portion 122a and containing relatively more organic matter can be supplied to the water to be treated spraying section 15, thereby improving the fermentation efficiency in the fermenter 11. In addition, the fermentation apparatus 102 of this embodiment has the same functions and effects as the fermentation apparatus 1 of the first embodiment.

[0055] (Embodiment 3) In this embodiment, an example of a fermentation apparatus 103 equipped with an electrode 35 that also functions as a partition wall will be described. As shown in FIG. 4, the fermentation apparatus 103 of this embodiment has a fermentation tank 11 and a partition plate 13 that divides the internal space 12 of the fermentation tank 11 into an upper space 121 and a lower space 122. The upper space 121 of the fermentation tank 11 is provided with a microorganism carrier 14 placed on the partition plate 13, and a treated water spraying section 15 and a sludge spraying section 6 arranged above the microorganism carrier 14. A gas outlet section 16 is provided at the upper end of the fermentation tank 11. A treated water discharge pipe 21 of the treated water discharge section 2 opens on the side surface of the lower space 122 of the fermentation tank 11. A plurality of electrodes 35 (35a, 35b) and a sludge discharge pipe 51 of the sludge discharge section 5 are provided at the bottom of the fermentation tank 11.

[0056] Furthermore, the fermentation apparatus 103 of this embodiment has a treated water circulation section 4 that sends the treated water W stored in the lower space 122 of the fermenter 11 to the treated water spraying section 15, a sludge circulation section 61 that sends the sludge stored in the lower space 122 to the sludge spraying section 6, and a treated water supply section 7 that supplies the treated water W to the lower space 122 of the fermentation tank 11 from the outside of the fermentation apparatus 103. The treated water circulation section 4 has a treated water circulation pipe 41 and a treated water circulation pump 42. Moreover, the sludge circulation section 61 has a sludge circulation pipe 611 and a sludge pump 612. The configurations of these parts in the fermentation apparatus 103 of this embodiment are the same as those of the fermentation apparatus 102 of the second embodiment.

[0057] Two electrodes 35, a first electrode 35a and a second electrode 35b, are provided in the lower space 122 of the fermenter 11 in the fermenter 103. The first electrode 35a in this embodiment is shaped like a plate having no through-holes. As shown in FIG. 4, the first electrode 35a faces an opening of the treated water circulation pipe 41 and an opening of the treated water supply pipe 71. As shown in FIG. 5, the first electrode 35a is disposed so that its plate surface is perpendicular to the central axis of the treated water circulation pipe 41.

[0058] 4 and 5, the lower space 122 of the fermenter 11 is divided into a first portion 122a and a second portion 122b by the first electrode 35a. Of the two portions 122a and 122b of the lower space 122, an opening of the treated water circulation pipe 41, an opening of the treated water supply pipe 71, and an opening of the sludge circulation pipe 611 are arranged in the first portion 122a.

[0059] In the second portion 122b of the lower space 122, an opening of the treated water discharge pipe 21, an opening of the sludge discharge pipe 51 of the sludge discharge section 5, and the second electrode 35b are arranged.

[0060] As shown in Figure 5, a gap is provided between the first electrode 35a and the side wall of the fermentation tank 11, and the treated water W and sludge are configured to flow through the gap between the first electrode 35a and the side wall of the fermentation tank 11.

[0061] The shape of the second electrode 35b is not particularly limited, and various shapes such as a plate shape, a net shape, a rod shape, etc. may be adopted. When the second electrode 35b has a plate shape, the second electrode 35b may or may not have a through hole. For example, the second electrode 35b in this embodiment has a plate shape having a through hole 351 as shown in FIG. 6. As shown in FIG. 5, a gap is provided between the second electrode 35b and the side wall of the fermenter 11, so that the water to be treated W and the sludge can flow through the through hole 351 and the gap between the second electrode 35b and the side wall of the fermenter 11.

[0062] The lower space 122 of the fermenter 11 in the fermenter 103 of this embodiment is divided into a first portion 122a and a second portion 122b by a plate-shaped first electrode 35a having no through-hole. In addition, an opening of the water-to-be-treated supply pipe 71 and an opening of the water-to-be-treated circulation pipe 41 are arranged in the first portion 122a of the lower space 122, and an opening of the water-to-be-treated discharge pipe 21 is arranged in the second portion 122b. Therefore, as in the fermenter 102 of the second embodiment, the water-to-be-treated W that flows in from the water-to-be-treated supply pipe 71 and is rich in organic matter can be retained in the first portion 122a of the lower space 122 and supplied to the water-to-be-treated spray section 15 via the water-to-be-treated circulation pipe 41. As a result, the fermentation efficiency in the fermenter 11 can be improved.

[0063] Furthermore, by using a plate-shaped electrode having through holes 351 as the second electrode 35b, the difference in surface area between the first electrode 35a and the second electrode 35b is reduced, and the progress of unintended secondary reactions due to current concentration on the second electrode 35b can be easily avoided. Furthermore, by providing the through holes 351 in the second electrode 35b, the water to be treated W and sludge can be permeated, and the water to be treated W can be more easily discharged from the water to be treated discharge section 2 and the sludge can be more easily discharged from the sludge discharge section 5. In addition, the fermentation apparatus 103 of this embodiment has the same effects as the fermentation apparatus 102 of the second embodiment.

[0064] (Embodiment 4) In this embodiment, examples of other shapes of the first electrode will be described. As shown in FIG. 7, the fermentation apparatus 104 of this embodiment has a fermentation tank 11 and a partition plate 13 that divides the internal space 12 of the fermentation tank 11 into an upper space 121 and a lower space. The upper space 121 of the fermentation tank 11 is provided with a microorganism carrier 14 placed on the partition plate 13, and a water to be treated spraying section 15 and a sludge spraying section 6 arranged above the microorganism carrier 14. A gas outlet section 16 is provided at the upper end of the fermentation tank 11. A water to be treated discharge pipe 21 of the water to be treated discharge section 2 opens on the side surface of the lower space 122 of the fermentation tank 11. A sludge discharge section 5 is provided at the bottom of the fermentation tank 11.

[0065] Furthermore, the fermentation apparatus 104 of this embodiment has a treated water circulation section 4 that sends the treated water W stored in the lower space 122 of the fermentation tank 11 to the treated water spraying section 15, a sludge circulation section 61 that sends the sludge stored in the lower space 122 of the fermentation tank 11 to the sludge spraying section 6, and a treated water supply section 7 that supplies the treated water W to the lower space 122 of the fermentation tank 11 from the outside of the fermentation apparatus 104. The treated water circulation section 4 has a treated water circulation pipe 41 and a treated water circulation pump 42. Moreover, the sludge circulation section 61 has a sludge circulation pipe 611 and a sludge pump 612. The configurations of these parts in the fermentation apparatus 104 of this embodiment are the same as those of the fermentation apparatus 103 of the third embodiment.

[0066] The fermentation apparatus 104 of this embodiment has two electrodes 36, a first electrode 36a and a second electrode 36b. The first electrode 36a and the second electrode 36b are both shaped like a plate having a through hole 361. The opening diameter of the through hole 361 in the first electrode 36a is smaller than the opening diameter of the through hole 361 in the second electrode 36b. As a result, the opening area ratio of the through hole 361 in the first electrode 36a, that is, the ratio of the total area of ​​the through hole 361 to the total area of ​​the first electrode 36a and the through hole 361 in a plan view of the first electrode 36a seen from the thickness direction, is lower than the opening area ratio of the through hole 361 in the second electrode 36b. The arrangement of the first electrode 36a and the second electrode 36b in the fermentation tank 11 is the same as the arrangement of the first electrode 35a and the second electrode 35b in the third embodiment.

[0067] In the case where a plate-shaped electrode having through holes 361 is used as the first electrode 36a as in this embodiment, it is preferable to set the opening area ratio of the through holes 361 in the first electrode 36a lower than the opening area ratio of the through holes 361 in the second electrode 36b. In this case, the water W to be treated and the sludge are less likely to pass through the first electrode 36a, so that the water W to be treated flowing from the water to be treated supply pipe 71 tends to remain in the first portion 122a of the internal space 12. In addition, since the difference in surface area between the first electrode 36a and the second electrode 36b can be more easily reduced, the progress of unintended secondary reactions due to the concentration of current on the second electrode 36b can be more easily avoided. As a result, the water W to be treated that is relatively rich in organic matter can be sent to the water to be treated spraying section 15 through the water to be treated circulation pipe 41, and the fermentation efficiency in the fermenter 11 can be improved.

[0068] (Embodiment 5) In this embodiment, an example of a fermentation apparatus 105 having a plurality of electrode pairs 371, 372 will be described. As shown in FIG. 8, the fermentation apparatus 105 of this embodiment has a fermentation tank 11 and a partition plate 13 that divides the internal space 12 of the fermentation tank 11 into an upper space 121 and a lower space 122. The upper space 121 of the fermentation tank 11 is provided with a microorganism carrier 14 placed on the partition plate 13, and a treated water spraying section 15 and a sludge spraying section 6 arranged above the microorganism carrier 14. In addition, a gas outlet section 16 is provided at the upper end of the fermentation tank 11. A treated water discharge pipe 21 of the treated water discharge section 2 opens into a side surface of the lower space 122 of the fermentation tank 11. A sludge discharge pipe 51 of the sludge discharge section 5 opens into the bottom of the fermentation tank 11.

[0069] Furthermore, the fermentation apparatus 105 of this embodiment has a treated water circulation section 4 that sends the treated water W stored in the lower space 122 of the fermenter 11 to the treated water spraying section 15, a sludge circulation section 61 that sends the sludge stored in the lower space 122 to the sludge spraying section 6, and a treated water supply section 7 that supplies the treated water W to the lower space 122 of the fermentation tank 11 from the outside of the fermentation apparatus 105. The treated water circulation section 4 has a treated water circulation pipe 41 and a treated water circulation pump 42. Moreover, the sludge circulation section 61 has a sludge circulation pipe 611 and a sludge pump 612. The configurations of these parts in the fermentation apparatus 105 of this embodiment are the same as those of the fermentation apparatus 103 of the third embodiment.

[0070] Four electrodes 37 (37a to 37d), namely, a first positive electrode 37a, a first negative electrode 37b, a second positive electrode 37c, and a second negative electrode 37d, are provided in the lower space 122 of the fermenter 11 in the fermenter 105. Of the four electrodes 37, the first positive electrode 37a and the first negative electrode 37b arranged opposite the first positive electrode 37a form a first electrode pair 371, and the second positive electrode 37c and the second negative electrode 37d arranged opposite the second positive electrode 37c form a second electrode pair 372.

[0071] More specifically, the four electrodes 37 are each shaped like a plate having no through-holes, and are arranged at intervals from one another so that the plate surface of each electrode 37 is perpendicular to the central axis of the water-to-be-treated circulating pipe 41, as shown in Fig. 9. Furthermore, of the four electrodes 37, the first positive electrode 37a faces the opening of the water-to-be-treated supply pipe 71 and the opening of the water-to-be-treated circulating pipe 41, and the second negative electrode 37d faces the opening of the water-to-be-treated discharge pipe 21, as shown in Fig. 8.

[0072] 9, the lower space 122 of the fermenter 11 is divided into a first portion 122a and a second portion 122b by the first positive electrode 37a. In the first portion 122a of the lower space 122, an opening of the water to be treated supply pipe (not shown), an opening of the water to be treated circulation pipe 41, and an opening of the sludge circulation pipe 611 are arranged. In addition, in the second portion 122b of the lower space, the first negative electrode 37b, the second positive electrode 37c and the second negative electrode 37d constituting the second electrode pair 372, an opening of the water to be treated discharge pipe 21, and an opening of the sludge discharge pipe 51 are arranged.

[0073] As shown in FIG. 8, the distance between the first positive electrode 37a and the first negative electrode 37b, and the distance between the second positive electrode 37c and the second negative electrode 37d are both shorter than the distance between the first electrode pair 371 and the second electrode pair 372, that is, the distance from the first negative electrode 37b to the second positive electrode 37c.

[0074] In this way, when the electrodes 37a-37d constitute a plurality of electrode pairs 371, 372 each consisting of a positive electrode and a negative electrode, by making the distance between the electrodes in each electrode pair shorter than the distance between the electrode pair and the electrode pair closest to the electrode pair, when a voltage is applied to each electrode pair, a current flows more easily between the electrodes constituting each electrode pair. As a result, it is expected that the fermentation efficiency in the lower space 122 of the fermenter 11 is further improved. In addition, the fermentation apparatus 105 of this embodiment has the same effects as the fermentation apparatus 103 of the third embodiment.

[0075] (Embodiment 6) In this embodiment, an example of a fermentation apparatus 106 having an electrical insulator 38 between the electrode pairs 371, 372 will be described. As shown in FIG. 10, the fermentation apparatus 106 of this embodiment has a fermentation tank 11 and a partition plate 13 that divides the internal space 12 of the fermentation tank 11 into an upper space 121 and a lower space 122. The upper space 121 of the fermentation tank 11 is provided with a microorganism carrier 14 placed on the partition plate 13, and a treated water spraying section 15 and a sludge spraying section 6 arranged above the microorganism carrier 14. In addition, a gas outlet section 16 is provided at the upper end of the fermentation tank 11. A treated water discharge pipe 21 of the treated water discharge section 2 opens into a side surface of the lower space 122 of the fermentation tank 11. A sludge discharge pipe 51 of the sludge discharge section 5 opens into the bottom of the fermentation tank 11.

[0076] Furthermore, the fermentation apparatus 106 of this embodiment has a treated water circulation section 4 that sends the treated water W stored in the lower space 122 of the fermenter 11 to the treated water spraying section 15, a sludge circulation section 61 that sends the sludge stored in the lower space 122 to the sludge spraying section 6, and a treated water supply section 7 that supplies the treated water W from the outside of the fermentation apparatus 106 to the lower space 122 of the fermentation tank 11. The treated water circulation section 4 has a treated water circulation pipe 41 and a treated water circulation pump 42. Moreover, the sludge circulation section 61 has a sludge circulation pipe 611 and a sludge pump 612. The configurations of these parts in the fermentation apparatus 106 of this embodiment are the same as those of the fermentation apparatus 103 of the third embodiment.

[0077] Four electrodes 37 (37a to 37d), namely, a first positive electrode 37a, a first negative electrode 37b, a second positive electrode 37c, and a second negative electrode 37d, are provided in the lower space 122 of the fermenter 11 in the fermenter 106. Of the four electrodes 37, the first positive electrode 37a and the first negative electrode 37b arranged opposite the first positive electrode 37a form a first electrode pair 371, and the second positive electrode 37c and the second negative electrode 37d arranged opposite the second positive electrode 37c form a second electrode pair 372.

[0078] More specifically, the four electrodes 37 are each shaped like a plate having no through-holes, and are arranged at intervals from one another so that the plate surface of each electrode 37 is perpendicular to the central axis of the water-to-be-treated circulating pipe 41, as shown in Fig. 11. Furthermore, of the four electrodes 37, the first positive electrode 37a faces the opening of the water-to-be-treated supply pipe 71 and the opening of the water-to-be-treated circulating pipe 41, and the second negative electrode 37d faces the opening of the water-to-be-treated discharge pipe 21, as shown in Fig. 10.

[0079] An electrical insulator 38 is provided between the first electrode pair 371 and the second electrode pair 372. The electrical insulator 38 in this embodiment has a plate shape without any through holes, similar to the electrode 37, and is disposed so that the plate surface is perpendicular to the central axis of the treated water circulation pipe 41, as shown in FIG.

[0080] 11, the lower space 122 of the fermenter 11 is divided into a first portion 122a and a second portion 122b by the first positive electrode 37a. In the first portion 122a of the lower space 122, an opening of the water to be treated supply pipe (not shown), an opening of the water to be treated circulation pipe 41, and an opening of the sludge circulation pipe 611 are arranged. In addition, in the second portion 122b of the lower space, the first negative electrode 37b, the second positive electrode 37c and the second negative electrode 37d constituting the second electrode pair 372, the electrical insulator 38, an opening of the water to be treated discharge pipe 21, and an opening of the sludge discharge pipe 51 are arranged.

[0081] In the case where the electrodes 37 are configured as a plurality of electrode pairs 371, 372 each consisting of a positive electrode and a negative electrode as in this embodiment, by providing an electrical insulator 38 between each electrode pair and the electrode pair closest to the electrode pair, when a voltage is applied to each electrode pair, a current can more easily flow between the electrodes constituting each electrode pair. As a result, it is expected that the fermentation efficiency in the lower space 122 of the fermenter 11 can be further improved. In addition, the fermentation apparatus 106 of this embodiment has the same effects as the fermentation apparatus 103 of the third embodiment.

[0082] Although examples of aspects of the fermentation apparatus have been described above based on embodiments 1 to 6, the specific aspects of the fermentation apparatus of the present invention are not limited to the above-mentioned embodiments, and the configuration can be appropriately changed without departing from the gist of the apparatus.

[0083] For example, in the embodiments 1 to 6, an example has been described in which sludge stored in the lower space 122 of the fermenter 11 is supplied to the sludge spraying section 6 by the sludge circulation section 61 and sprayed from the sludge spraying section 6, but by connecting the sludge circulation piping 611 to the treated water spraying section 15, the treated water spraying section 15 can also be used as the sludge spraying section 6.

[0084] In addition, in the first to sixth embodiments, examples of the fermentation apparatuses 1, 102 to 106 are shown in which a plurality of electrodes 3, 35 to 37 are provided in the lower space 122, and a voltage is applied between these electrodes to pass a current through the sludge, but it is also possible to pass a current through the sludge without providing electrodes in the lower space 122, and instead apply a voltage to members that face the lower space 122, such as the wall surface of the fermentation tank 11, the treated water discharge pipe 21, the treated water circulation pipe 41, the sludge discharge pipe 51, and the sludge circulation pipe 611. Furthermore, it is also possible to provide one electrode in the lower space 122, and apply a voltage between this electrode and a member that faces the lower space 122 to pass a current through the sludge. [Explanation of symbols]

[0085] 1, 102~106 Fermentation equipment 11 Fermentation tank 12 Interior Space 121 Upper space 122 Lower space 13 Partition 14 Microbial carriers 15 Treated water spraying section 2 Treated water discharge section 21 Treated water discharge pipe

Claims

1. A fermentation apparatus configured to ferment organic matter by contacting water to be treated containing organic matter with sludge containing microorganisms, A fermentation tank; A partition plate disposed in the fermenter and dividing the internal space of the fermenter into an upper space and a lower space; A plurality of microorganism carriers arranged in the upper space and configured to be capable of carrying the sludge; A water-to-be-treated spraying unit that sprays the water to be treated onto the microorganism carrier; a treated water discharge section that is provided with a treated water discharge pipe that opens into the lower space and discharges the treated water stored in the lower space to the outside of the fermentation apparatus; A fermentation apparatus configured so that an electric current can be applied to the sludge stored in the lower space.

2. The fermentation apparatus according to claim 1, further comprising a treated water circulation piping that opens into the lower space, and a treated water circulation pump that is provided on the path of the treated water circulation piping, and has a treated water circulation section that sends the treated water stored in the lower space to the treated water spray section.

3. The fermentation apparatus according to claim 2 , further comprising a water-to-be-treated supply section that is provided with a water-to-be-treated supply pipe that opens into the lower space and that supplies the water to be treated from outside the fermentation apparatus to the lower space.

4. The fermentation apparatus of claim 3 has a partition portion that divides the lower space into a first portion and a second portion, and an opening of the treated water circulation pipe and an opening of the treated water supply pipe are located in the first portion of the lower space, and an opening of the treated water discharge pipe is located in the second portion of the lower space.

5. The fermentation apparatus according to claim 3 , further comprising an electrode disposed in the lower space for applying an electric current to the sludge stored in the lower space.

6. The fermentation apparatus has a first electrode and a second electrode as the electrodes, the first electrode has a plate-like shape without a through hole and divides the lower space into a first portion and a second portion; an opening of the water-to-be-treated circulation pipe and an opening of the water-to-be-treated supply pipe are located in the first portion of the lower space, The fermentation apparatus according to claim 5 , wherein the opening of the discharge pipe for treated water and the second electrode are located in a second portion of the lower space.

7. The fermentation apparatus according to claim 6 , wherein the second electrode is in the form of a plate having through holes.

8. The fermentation apparatus has a first electrode and a second electrode as the electrodes, the first electrode has a plate-like shape having a through hole and divides the lower space into a first portion and a second portion; an opening of the water-to-be-treated circulation pipe and an opening of the water-to-be-treated supply pipe are located in the first portion of the lower space, an opening of the water discharge pipe and the second electrode are located in the second portion of the lower space, The second electrode has a plate shape having a through hole, The fermentation apparatus according to claim 5 , wherein an opening area ratio of the through-holes in the first electrode is lower than an opening area ratio of the through-holes in the second electrode.

9. The fermentation apparatus according to claim 1 , further comprising an electrode disposed in the lower space for applying an electric current to the sludge stored in the lower space.

10. The fermentation apparatus according to claim 9, wherein the plurality of electrodes constitute a plurality of electrode pairs each consisting of a positive electrode and a negative electrode, and the distance between the positive electrode and the negative electrode in each of the electrode pairs is shorter than the distance between the electrode pair and a closest electrode pair to the electrode pair.

11. The fermentation apparatus according to claim 9 , wherein the plurality of electrodes constitute a plurality of electrode pairs each consisting of a positive electrode and a negative electrode, and an electrical insulator is provided between each of the electrode pairs and an electrode pair closest to the electrode pair in question.

12. The fermentation apparatus according to any one of claims 1 to 11, wherein the untreated water spraying section is disposed above the microorganism carrier.

13. The fermentation apparatus according to any one of claims 1 to 11, comprising a sludge spraying section disposed above the microbial carrier and spraying the sludge onto the microbial carrier, and a sludge circulation section disposed in the lower space and sending the sludge stored in the lower space to the sludge spraying section.

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