Biological deodorization device

Abstract

To provide a biological deodorization apparatus which can improve the deodorization efficiency of the odorous gas having an odorous component.SOLUTION: A biological deodorization apparatus for deodorizing odorous gas by microorganisms comprises: a filling layer 5 which stores a carrier that carries the microorganisms; a liquid tank 6 which holds liquid 7 supplied to the filling layer 5; and an air bubble layer generation mechanism which generates air bubbles B in the liquid 7 in the liquid tank 6 to grow an air bubble layer BL on the liquid tank 6. The liquid 7 has the viscosity by including a viscosity component. The odorous gas passes through the filling layer 5 and the deodorization treatment is performed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a biological deodorizing apparatus for treating a gas containing odor components.

Background Art

[0002] For example, gases generated in a night soil treatment plant, a sewage treatment plant, etc. generally contain sulfur-based odor components such as ammonia, hydrogen sulfide, methyl mercaptan, methyl sulfide, and dimethyl disulfide. As a deodorizing apparatus for treating a gas containing odor components (hereinafter sometimes referred to as an odorous gas), a wet deodorizing apparatus that chemically reacts the odor components in the gas with a chemical solution in a deodorizing tower, and a biological deodorizing apparatus that decomposes the odor components with microorganisms are known. The biological deodorizing apparatus is excellent in that it is easier to maintain and manage than a wet deodorizing apparatus using a chemical solution, and has a low running cost.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a night soil treatment plant, when night soil is introduced into a night soil receiving tank by a sanitation vehicle (vacuum truck), or in a sewage treatment plant during a time period when a large amount of sewage flows in, the concentration of the odor components in the odorous gas may rapidly increase compared to the concentration of the odor components during normal times other than these. FIG. 7 is a graph showing an example of the time dependence of the concentration of hydrogen sulfide, which is an odor component. It can be seen that the concentration of hydrogen sulfide rapidly increases in a specific time period A and then rapidly decreases. Since it takes several hours for microbial cell division, unlike a deodorization device using a chemical reaction with a chemical solution, a biological deodorization device cannot increase or decrease its deodorization ability in accordance with a sudden change in the concentration of an odor component. If the deodorization ability is insufficient, the burden on the activated carbon adsorption tower provided downstream of the biological deodorization device increases, the replacement cycle of the activated carbon becomes shorter, and the running cost increases. Also, if the deodorization ability of the deodorization device is set according to the odor component with the maximum concentration, it becomes necessary to increase the capacity of the deodorization device, leading to an increase in maintenance management costs and running costs. Therefore, further improvement in the deodorization efficiency of biological deodorization devices is desired.

[0005] An object of the present invention is to provide a biological deodorization device capable of improving deodorization efficiency.

Means for Solving the Problems

[0006] The biological deodorization device according to the present invention is a biological deodorization device that deodorizes odorous gas with microorganisms, a packing layer 5 that houses a carrier carrying the microorganisms, a liquid tank 6 that holds a liquid 7 supplied to the packing layer 5, and a bubble layer generation mechanism that generates bubbles B in the liquid 7 in the liquid tank 6 to form a bubble layer BL on the liquid tank 6, the liquid 7 has viscosity by containing a viscous component, and the odorous gas is configured to pass through the packing layer 5.

[0007] In the above configuration, the bubble layer generation mechanism may be configured to form the bubble layer BL in the packing layer 5.

[0008] By generating bubbles in a liquid having viscosity due to a viscous component and forming a bubble layer as described above, the removal rate of odor components can be increased. In particular, since the liquid has viscosity, it is possible to form a bubble layer up to the packing layer, and depending on the height of the bubble layer in the packing layer, it is possible to increase the removal rate of odor components.

[0009] In the above configuration, The viscous component may be configured to be a biologically-derived viscous substance.

[0010] In the above configuration, The packing layer 5 may be configured to accommodate a viscosity-imparting organism that generates a viscous substance as the viscous component.

[0011] By using a biologically-derived viscous substance as the viscous component that imparts viscosity to the liquid, the maintenance and management of the biological deodorization device become even easier. Also, by accommodating the viscosity-imparting organism in the packing layer, a device for separately imparting viscosity to the liquid becomes unnecessary, and the device configuration becomes simple.

[0012] In the above configuration, The packing layer 5 may be configured to accommodate an auxiliary organism that supplies nutrients to assist the survival of the viscosity-imparting organism.

[0013] The auxiliary organism assists the survival of the viscosity-imparting organism that generates the viscous substance, and further facilitates the maintenance and management of the biological deodorization device.

[0014] In the above configuration, The packing layer 5 may be configured to have a main carrier layer 52 configured with the viscosity-imparting organism as a carrier and sub-carrier layers 51, 53 configured with the auxiliary organism as a carrier.

[0015] By configuring the packing layer in this way as a packing layer composed of a main carrier layer and sub-carrier layers, maintenance becomes easy.

[0016] In the above configuration, The auxiliary organism may be configured to be selected from Gramineae plants, Cyperaceae plants, and herbs.

[0017] In the above configuration, The viscosity-imparting organism may be configured to be brown algae.

[0018] By using such an auxiliary organism or viscosity-imparting organism, the packed layer can be easily and safely formed.

[0019] In the above configuration, The viscosity-imparting organism of the main carrier layer 52 may be brown algae, and the main carrier layer 52 may be configured to be disposed above the sub-carrier layers 51 and 53.

[0020] By adopting such an arrangement, the stable generation effect of the bubble layer can be particularly enhanced.

[0021] In the above configuration, The viscous component may be configured to be a thickener.

[0022] In the above configuration, It is also possible to use a thickener as the viscous component. It is also possible to select a configuration that is easy to control industrially.

[0023] Further, the biological deodorization device according to the present invention has a gas introduction part 3 for introducing the odorous gas into the packed layer 5, the gas introduction part 3 has a gas discharge port 15, the gas discharge port 15 is located below the liquid level of the liquid 7 in the liquid tank 6, the gas introduction part 3 is characterized by constituting the bubble layer generation mechanism.

[0024] By adopting such a biological deodorization device, by using the odorous gas, it is possible to easily generate bubbles in the liquid and form a bubble layer.

[0025] In addition, the biological deodorization device according to the present invention The bubble layer generation mechanism includes an air supply pump 30 and a bubble generation nozzle 31 connected to the air supply pump 30. The air supply pump 30 supplies air or the odorous gas to the bubble generation nozzle 31. The bubble generation nozzle 31 is located below the liquid level of the liquid 7 in the liquid tank 6.

[0026] By using the biological deodorization device with such a configuration, it becomes possible to control the formation of the bubble layer without relying on the odorous gas by means of the air supply pump and the bubble generation nozzle.

[0027] In the above configuration, the air supply pump 30 may be configured such that the exhaust volume is controlled according to the odor component concentration of the odorous gas.

[0028] By using the biological deodorization device with such a configuration, it is possible to efficiently remove the odor components of the odorous gas.

Effect of the Invention

[0029] According to the biological deodorization device of the present invention, it is possible to improve the deodorization efficiency.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0031] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, none of the following embodiments gives a limiting interpretation in the determination of the gist of the present invention. Also, the same or similar members may be denoted by the same reference numerals, and the description thereof may be omitted.

[0032] Furthermore, with regard to terms used in this specification for specifying shapes, geometric conditions, and their degrees, such as terms like "parallel", "orthogonal", "identical", etc., and values of lengths and angles, etc., they shall not be bound by a strict meaning and shall be interpreted to include a range to the extent that similar functions can be expected.

[0033] (Embodiment 1) <Device Configuration> Fig. 1(A) shows the configuration of the biological deodorizing apparatus 100 according to Embodiment 1, and Fig. 1(B) is a schematic diagram for explaining the operating state of the biological deodorizing apparatus 100. As shown in FIG. 1, the deodorizing device 100 includes a deodorizing tower 1. The gas to be treated G (for example, an odorous gas containing sulfur-based odorous components such as ammonia and hydrogen sulfide), which is the odorous component to be treated, is taken in from the gas inlet 2 of the deodorizing tower 1 and introduced into the deodorizing tower 1 by the first pipe 3 (gas introduction section 3). A blower 4 (air blower 4) may be provided in the first pipe 3 to send the gas to be treated G into the deodorizing tower 1. For simplicity, the gas to be treated G, which is an odorous gas, is referred to as gas G.

[0034] Inside the deodorizing tower 1, a packing layer 5 and a liquid tank 6 (circulation liquid tank 6) are provided below the packing layer 5. The packing layer 5 contains a carrier (immobilizes) that supports (immobilizes) known microorganisms that decompose odorous components, such as Thiobacillus bacteria. The gas G is introduced into the packing layer 5 in the deodorizing tower 1 by the first pipe 3 and passes through the packing layer 5. As the carrier for the microorganisms, for example, in addition to granular porous ceramics and wood chips, known carriers can be used. The carrier is housed in a mesh container made of wire mesh, plastic, etc. and held in the packing layer 5. Further, the holding means of the carrier is not limited to the mesh container. For example, the carrier may be held on a mesh partition plate (or partition mesh) made of plastic or the like. The mesh container only needs to be made of a non-corrosive material.

[0035] The liquid tank 6 is provided as a liquid-tight space below the packing layer 5. The liquid tank 6 holds a liquid 7 (circulation liquid 7) mainly composed of water necessary for the survival of microorganisms.

[0036] The liquid tank 6 is provided with a first discharge port 8 (circulation liquid discharge port 8). A second pipe 9 is connected to the first discharge port 8, and the second pipe 9 is connected to the inlet of a pump 10 (circulation pump 10) provided outside the deodorizing tower 1. A third pipe 11 (circulation pipe 11) is connected to the outlet of the pump 10. The tip of the third pipe 11 is inserted into the deodorizing tower 1 through the inlet 12. A liquid discharge part 13 (spray nozzle 13) is provided at the tip of the third pipe 11, and the liquid discharge part 13 is disposed above the packing layer 5.

[0037] In addition, when the ambient temperature is low, in order to prevent a decrease in the activity of microorganisms, a temperature adjustment mechanism such as a heater may be provided in the liquid tank 6 or the third pipe 11 so as to maintain a predetermined temperature for the liquid 7.

[0038] By operating the pump 10, the liquid 7 in the liquid tank 6 is ejected to the packing layer 5 through the liquid discharge part 13. The liquid 7 ejected to the packing layer 5 returns to the liquid tank 6 again. The second pipe 9, the pump 10, and the third pipe 11 constitute a circulation mechanism for circulating the liquid 7. After the liquid 7 is supplied to the packing layer 5, it passes through the packing layer 5 and returns to the liquid tank 6. Therefore, microorganisms carried on the carriers of the packing layer 5 also inhabit the liquid 7.

[0039] A gas discharge part 14 provided in the deodorizing tower 1 is provided at the tip of the first pipe 3. The gas discharge part 14 is formed by, for example, a cylindrical pipe, and further provided with a blowout port 15 (gas discharge port 15). The blowout port 15 is provided, for example, on the bottom side of the gas discharge part 14, and may be constituted by a circular through-hole of, for example, 1 mm or more and 10 mm or less. Further, a porous plate having minute holes may be installed in the opening provided at the bottom of the gas discharge part 14. The blowout port 15 is disposed in the liquid 7 of the liquid tank 6 in order to discharge the gas G into the liquid 7. The blowout port 15 is located below the liquid level of the liquid 7. Note that by providing the blowout port 15 on the bottom side of the gas discharge part 14, blockage of the blowout port 15 can be prevented.

[0040] As described below, since the air outlet 15 is used for the purpose of generating bubbles in the liquid 7, the distance of the air outlet 15 from the liquid surface may be set arbitrarily as long as bubbles can be generated in the liquid 7 by the gas G discharged from the air outlet 15. For example, the distance of the air outlet 15 from the liquid surface can be set so that even if the liquid surface of the liquid 7 fluctuates due to the generation of bubbles, the air outlet 15 is completely covered by the liquid 7, and the distance from the liquid surface to the liquid surface shell is longer than the diameter of the generated bubbles. However, as the distance from the liquid surface increases, the load on the blower 4 increases due to the liquid pressure of the liquid 7 in the liquid tank 6. Therefore, by arranging the air outlet 15 near the liquid surface, for example, at a position 2 cm or more and 20 cm or less below the liquid surface, the load on the blower 4 can be reduced, and it is not necessary to increase the capacity of the blower 4. The distance of the air outlet 15 from the liquid surface may be determined so that the increase in the load on the blower 4, specifically, the increase in the torque or power consumption of the motor, is 10% or less. Note that when the blowing ability of the blower 4 is sufficiently high, it is not excluded to set the installation position of the air outlet 15 deeper.

[0041] The biological deodorization device 100 is provided with a discharge pipe 16 for discharging the liquid 7, and a valve 17 is provided in the discharge pipe 16. The discharge pipe 16 can be used to periodically discharge a part of the liquid 7 for discharging dead microorganisms and adjusting the pH value, etc., or for exchanging the liquid 7.

[0042] As described below, the biological deodorization device 100 is configured to generate bubbles B from the air outlet 15 and grow the bubble layer BL. Therefore, the biological deodorization device 100 is provided with a viscosity-imparting mechanism for supplying a component (hereinafter referred to as a viscosity component) that imparts viscosity to the liquid 7 in order to increase the strength of the bubble film, which is the film of the generated bubbles (bubbles), prevent the collapse of the bubbles, or extend the life of the bubbles and keep the bubbles sustainable. The viscosity-imparting mechanism includes a chemical tank 18 that stores a thickener as a viscosity component, a pump 19 (delivery pump 19) that sends out the thickener stored in the chemical tank 18 to the liquid tank 6, and a fourth pipe 20 for introducing the thickener into the deodorization tower 1.

[0043] As the thickener, known thickeners can be used, for example, polyvinyl alcohol, methylcellulose-based thickeners, sodium alginate, starch (aqueous solution or powder), etc., but it is not limited thereto. The concentration (addition rate) of the thickener in the liquid 7 is preferably 0.01% or more and 3% or less, more preferably 0.1% or more and 1% or less. The concentration of the thickener can be monitored, and the pump 19 can be controlled to keep the concentration of the thickener in the liquid 7 constant. In addition, the thickener may be added manually. As the thickener, industrially produced commercially available thickeners can be used, and it is easy to control the viscosity according to the concentration of the thickener.

[0044] The biological deodorization device 100 may have a pH adjustment mechanism for adjusting the pH value of the liquid 7 to an optimal range for the growth of microorganisms (for example, 1 or more and 7 or less of the pH value). The range of the pH value is not limited to the above, and it may be set according to the microorganisms to be adopted. The pH adjustment mechanism includes a neutralization liquid tank 21 that holds a neutralization solution (for example, a sodium hydroxide solution) for neutralizing the acid in the liquid 7 when the concentration of the acid in the liquid 7 increases due to the decomposition of the odor component by microorganisms, a pump 22 (neutralization pump 22) that sends out the neutralization solution held in the neutralization liquid tank 21 to the liquid tank 6, and a fifth pipe 23 for introducing the neutralization solution into the deodorization tower 1.

[0045] The biological deodorization device 100 may have a liquid supply mechanism (circulating liquid supply mechanism) for supplying the liquid 7. The liquid supply mechanism includes, for example, a liquid tank 24 (water tank 24), a supply liquid (circulating liquid) held in the liquid tank 24, for example, a pump 25 (supply pump 25) that sends out water to the liquid tank 6, and a sixth pipe 26 for introducing the supply liquid (circulating liquid) into the deodorization tower 1.

[0046] The biological deodorization device 100 has a gas discharge port 28 (exhaust port 28), and the gas G that has completed the deodorization treatment in the deodorization tower 1 is discharged from the gas discharge port 28 to the outside of the deodorization tower 1. The gas G passes through a gas flow path that flows in the order of the first pipe 3, the packed bed 5, and the gas outlet 28 of the biological deodorization device 100, and deodorization treatment is performed. The gas G that has been deodorized and discharged from the gas outlet 28 may be released into the atmosphere, for example. However, it may also be further introduced into an adsorption tower having a physical adsorbent such as activated carbon, which is provided connected to the gas outlet 28 of the biological deodorization device 100, and two-stage deodorization treatment may be performed.

[0047] Note that, above the packed bed 5, a gas-liquid separation device 29 (demister 29) may be provided between the liquid discharge part 13 and the gas outlet 28. As will be described later, in order to generate bubbles using the liquid 7, the bubbles are carried by the airflow of the gas G, and the liquid 7 is likely to be lost. The gas-liquid separation device 29 can separate the gas G and the liquid 7 and remove the liquid 7 in the gas G. The gas-liquid separation device 29 has the effect of preventing the bubbles from flowing out and reducing the loss of the liquid 7. Note that, as the gas-liquid separation device 29, a known device composed of, for example, a wire mesh or the like can be used. The separated liquid 7 falls to the packed bed 5 below.

[0048] <Deodorization treatment> Hereinafter, with reference to FIG. 1(B), the deodorization treatment by the biological deodorization device 100 will be described. At least a part of the gas discharge part 14 is immersed in the liquid 7 in the liquid tank 6, and the air outlet 15 is located below the liquid surface of the liquid 7. The gas G discharged from the air outlet 15 generates bubbles B in the liquid 7 in the liquid tank 6. The bubbles B rise in the liquid 7 and reach the liquid surface of the liquid 7. Since the liquid 7 is imparted with viscosity by the added viscous component, the strength of the foam film composed of the liquid 7 of the generated bubbles B is increased, and many bubbles B do not disappear immediately. Therefore, the bubbles B are accumulated on the liquid surface of the liquid 7 within the range of their lifetime, generating and growing a bubble layer BL. As a result, due to the bubbling action of the air outlet 15, the bubble layer BL can grow up to the position of the packed bed 5. That is, the bubble layer BL will be formed even inside the packed bed 5. In the biological deodorization device 100, the first pipe 3 (particularly, the gas discharge part 14 and the blowout port 15 provided at its tip) constitutes a bubble layer generation mechanism.

[0049] The height (H) of the bubble layer BL in the packing layer 5 depends on the air volume of the gas G, the shape of the blowout port 15, and the concentration of the viscous component (thickener) in the liquid 7. Therefore, the height (H) of the bubble layer BL can be controlled according to these conditions. The height (H) of the bubble layer BL is such that at least a part of the wall surface of the packing layer 5 of the deodorization tower 1 is made of a transparent material, such as transparent PVC (polyvinyl chloride), acrylic plate, transparent glass, etc., so that it can be visually confirmed. Note that the height (H) of the bubble layer BL can also be detected by an optical detection device provided outside the transparent wall surface part of the deodorization tower 1.

[0050] Note that since the bubble layer BL has a liquid film of the liquid 7, the liquid 7 can be supplied to the packing layer 5 by the bubble layer BL. However, the liquid 7 discharged from the liquid discharge part 13 and supplied to the packing layer 5 has the effect of contacting the bubbles B of the bubble layer BL and disappearing the bubbles B. Therefore, the growth of the bubble layer BL from below and the defoaming of the bubbles B on the surface of the bubble layer BL from above can further stabilize the height (H) of the bubble layer BL. Also, the dead bodies of the microorganisms supported on the packing layer 5 can be washed away into the liquid tank 6.

[0051] FIG. 2 is a diagram for explaining the removal effect (deodorization effect) of the odor components of the biological deodorization device 100. FIG. 2(A) shows the relationship between the height (H) of the bubble layer BL in the packing layer 5 and the removal rate, and FIG. 2(B) shows the relationship between the height (H) of the bubble layer BL in the packing layer 5 and the pressure loss of the packing layer 5. Note that the removal rate was calculated by measuring the inlet concentration and the outlet concentration of the odor components and using the formula: removal rate = [outlet concentration] / [inlet concentration]. The pressure loss was measured by the difference between the pressure of the gas G at the upper part P2 of the packing layer 5 and the pressure of the gas G at the lower part P1 of the packing layer 5. (See FIG. 1)

[0052] From FIGS. 2(A) and 2(B), it can be understood that as the height (H) of the bubble layer BL increases, the removal rate increases and the pressure loss increases. That is, it can be understood that by forming the bubble layer BL, the removal rate of the biological deodorization device 100 is significantly improved. It is considered that the removal rate of the conventional deodorization device using microorganisms is lower than the removal rate when the height (H) of the bubble layer BL in FIG. 2(A) is 0 cm. Therefore, since the biological deodorization device 100 can greatly improve the removal rate of odor components, it is possible to treat the gas G of high-concentration odor components without increasing the capacity compared with the conventional deodorization device.

[0053] The reason for the increase in the removal rate as described above is considered that when the bubble layer BL grows, a pressure loss occurs in the packing layer 5, the residence time of the gas G in the packing layer 5 increases, and the decomposition of odor components is improved. Furthermore, the gas G confined in each bubble contacts the microorganisms present in the film (bubble film) of the bubble until the bubble collapses. Therefore, the gas G in the bubble is also effectively deodorized. Since the bubble layer BL itself has the effect of improving the deodorization efficiency, even when the bubble layer BL on the surface of the liquid 7 in the liquid tank 6 does not reach the packing layer 5, an improvement in the removal rate can be obtained. However, by growing the bubble layer BL until it reaches the packing layer 5, a pressure loss is generated in the packing layer 5, and a further improvement effect of the removal rate can be obtained.

[0054] Also, it is known that many microorganisms inhabit the liquid 7. Actually, the number of microorganisms in the liquid 7 in the liquid tank 6 may be larger than the number of microorganisms supported on the carrier of the packing layer 5. Therefore, by discharging the gas G from the blowout port 15 into the liquid 7 in the liquid tank 6, it is also possible to decompose the odor components by the microorganisms in the liquid 7 in the liquid tank 6. However, in order to obtain an effective improvement in deodorization efficiency, it is necessary to arrange the blowout port 15 at a deep position in the liquid tank 6, which increases the load on the blower 4 due to the hydraulic pressure of the liquid 7 and requires a large blower. Therefore, conventionally, it has been difficult to effectively utilize the microorganisms in the liquid 7. However, by incorporating microorganisms into the bubble layer BL composed of bubbles having a foam film strengthened by viscosity and allowing the microorganisms in the liquid 7 to exist in the packed bed 5, which is the passage route of the gas G, for a long time, the opportunity for more microorganisms to come into contact with the gas G can be increased, and the contact time with the microorganisms can be lengthened. As a result, the microorganisms in the liquid 7 can be effectively utilized, and the deodorization efficiency of the gas G can be significantly increased.

[0055] From FIG. 2(B), it can be understood that the pressure loss is minor compared to the atmospheric pressure (about 101 kPa). The biological deodorization device 100 can obtain a very significant improvement effect in deodorization efficiency with such a minor pressure loss. Also, since the blower 4 operates under conditions around normal atmospheric pressure, it can also be understood that it is not substantially affected by the pressure loss due to the bubble layer BL.

[0056] Conventional deodorization devices using microorganisms improved or controlled the deodorization efficiency by increasing the number of microorganisms. However, as described above, the biological deodorization device 100 can also improve and control the deodorization efficiency according to the height of the bubble layer BL.

[0057] (Embodiment 2) The biological deodorization device 100 can significantly increase the removal rate by generating the bubble layer BL of the liquid 7. In Embodiment 1, the gas G was introduced using the gas discharge part 14 immersed in the liquid 7 in the liquid tank 6 to generate the bubble layer BL. In Embodiment 2, a bubble layer generation mechanism for generating the bubble layer BL is provided independently in the liquid tank 6 separately from the gas discharge part 14.

[0058] FIGS. 3(A) and (B) are schematic diagrams for explaining the configuration of the biological deodorization device 100 of Embodiment 2. For visibility, the pH value adjustment mechanism and the liquid supply mechanism are omitted in FIG. 3. As shown in FIG. 3(A), the biological deodorization device 100 is provided with a bubble layer generation mechanism. The bubble layer generation mechanism has an air supply pump 30 (air pump 30) and a bubble generation nozzle 31 (bubbling nozzle 31). The bubble generation nozzle 31 can use, for example, a cylindrical pipe with fine holes provided on the surrounding side walls, a hollow disk with a porous plate, or other commercially available nozzles for generating bubbles in order to generate bubbles.

[0059] The air supply pump 30 and the bubble generation nozzle 31 are connected by a seventh pipe 32. The bubble generation nozzle 31 is arranged below the liquid level of the liquid 7 in the liquid tank 6 or in the liquid 7. The air supply pump 30 takes in air from the atmosphere and sends the air to the bubble generation nozzle 31 through the seventh pipe 32. The air sent from the air supply pump 30 is discharged as bubbles B into the liquid 7 from the bubble generation nozzle 31. Since a thickening agent is added to the liquid 7, the bubbles B generated by the bubble generation nozzle 31 generate a bubble layer BL as shown in Fig. 1(B). The bubble layer BL can increase the removal rate of the biological deodorization device 100.

[0060] Note that if the bubble generation nozzle 31 is close to the bottom surface of the liquid tank 6, it is easier to take in dead microorganisms and the like sedimented at the bottom of the liquid tank 6 into the bubbles B, and the lifespan of the bubbles B decreases. The bubble generation nozzle 31 is preferably arranged near the liquid level of the liquid tank 6. The distance from the liquid level of the arrangement position of the bubble generation nozzle 31 can be set to the same distance as the example of the air outlet 15 in Embodiment 1. Also, in order to avoid blockage, the bubble generation nozzle 31 is preferably arranged downward.

[0061] Different from Embodiment 1, since the bubble layer BL is generated by a bubble layer generation mechanism having an air supply pump 30 and a bubble generation nozzle 31, it is not necessary to generate bubbles using the gas discharge portion 14. Therefore, it is not necessary to immerse the gas discharge portion 14 in the liquid 7, and it can be arranged above the surface of the liquid 7. The burden on the blower 4 for sending the gas G is further reduced.

[0062] Also, with this bubble layer generation mechanism, the generation amount or height of the bubble tank BL can be easily controlled. Therefore, it is possible to control the height (H) of the bubble layer BL to increase during a time period when an increase in the inflow rate of the gas G or an increase in the concentration of the odor component is expected. For example, the exhaust volume of the air supply pump 30 may be controlled by a control device 33 (controller 33) having a timing function, and the amount of air supplied from the air supply pump 30 to the bubble generation nozzle 31 may be controlled. In this way, the deodorizing ability can be controlled according to the change in the concentration of the odor component predicted in advance, the deodorizing treatment can be efficiently performed, and the running cost can be reduced.

[0063] Note that, as shown in FIG. 3(B), the configuration in which the gas discharge portion 14 is arranged to be immersed in the liquid 7 in the second embodiment is not excluded. Providing this bubble layer generation mechanism and generating and controlling the bubble layer BL can also be combined with other embodiments.

[0064] Furthermore, it is also possible to automatically control the height of the bubble layer BL according to the concentration of the odor component of the gas G. As shown in FIG. 3(B), a sensor 34, for example, a gas concentration meter such as a hydrogen sulfide meter, is provided in the first pipe 3, and the output of the sensor 34 is input to the control device 33. The control device 33 controls the air supply pump 30 according to the concentration of the odor component output from the sensor 34. For example, when an increase in the odor component concentration is detected, the exhaust volume of the air supply pump 30 can be increased to increase the height (H) of the bubble layer BL. Conversely, when the odor component concentration decreases, the exhaust volume of the air supply pump 30 can be decreased to decrease the height of the bubble layer BL. The biological deodorization device 100 can be operated more efficiently without waste and contribute to the reduction of the running cost. Needless to say, the mechanism for automatically controlling the height of the bubble layer BL described above is applicable to the configuration of FIG. 3(A).

[0065] Note that, as the sensor 34, in addition to a gas concentration meter, a pressure gauge or a flow meter may be adopted, and the air supply pump 30 may be controlled according to the inflow rate of the gas G into the biological deodorization device 100.

[0066] Alternatively, a part of the gas G may be supplied to the bubble generation nozzle 31, and bubbles may be generated by the gas G in the same manner as in the first embodiment. As shown in FIG. 3(B), an eighth pipe 35 branched from the first pipe 3 is connected to the inlet side of the air supply pump 30. The air supply pump 30 supplies the gas G to the bubble generation nozzle 31, and the bubble generation nozzle 31 generates bubbles filled with the gas G. By confining the gas G in the bubbles B generated by the bubble generation nozzle 31 and deodorizing the gas G in the bubbles B, the deodorizing efficiency can be further improved. Note that FIG. 3(B) shows an example in which the eighth pipe 35 branches from the first pipe 3 on the upstream side of the blower 4, but is not limited thereto. The eighth pipe 35 may branch from the first pipe 3 on the downstream side of the blower 4. Needless to say, the mechanism for generating bubbles by the gas G described above is applicable to the configuration of FIG. 3(A).

[0067] Further, the height (H) of the bubble layer BL can be measured from the outer wall surface of the deodorizing tower 1. The height (H) of the bubble layer BL can be measured by using a measuring instrument 36, for example, a one-dimensionally arranged optical detection device (linear sensor) or the like for reflected light or transmitted light from the bubble layer BL. By inputting the output of the measuring instrument 36 to the control device 33 and controlling the output of the air supply pump 30, it becomes easier to control the height of the bubble layer BL.

[0068] In a conventional deodorizing device using microorganisms, it was impossible to change the deodorizing efficiency (or deodorizing ability) according to the time zone, gas inflow rate, and odor component concentration. However, by controlling the height of the bubble layer BL according to the state of the gas G by the independently controllable air supply pump 30, the deodorizing efficiency (or deodorizing ability) can be appropriately adjusted.

[0069] (Embodiment 3) In the first and second embodiments, the viscous component, i.e., the thickener, was provided by the viscosity imparting mechanism. In the third embodiment, a biological deodorizing apparatus 100 is provided that enables the operation of the apparatus to be facilitated, reduces the burden on the operator, and reduces running costs by eliminating the need to supply a thickening agent. The packing layer 5 itself serves as a component of the viscosity-imparting mechanism, and by supplying a biologically-derived viscous substance as a viscous component from the packing layer 5 to the liquid 7, the work burden can be reduced and the running cost can be reduced. In addition, since no separate viscosity-imparting mechanism is required, the configuration of the biological deodorizing apparatus 100 is also simplified. For example, fucoidan can be preferably adopted as the biologically-derived viscous component.

[0070] As a method for supplying the viscous component, a living organism that generates a viscous substance (hereinafter sometimes referred to as a viscosity-imparting organism) is adopted as the carrier of the packing layer 5, and microorganisms are supported on the carrier derived from the viscosity-imparting organism. By spraying the liquid 7 from the liquid discharge part 13 located above onto the packing layer 5, the viscous component can be contained in the liquid 7. Note that a carrier such as ceramic or wood chips may be mixed with a biologically-derived carrier (hereinafter sometimes referred to as a biological type carrier) and used. Microorganisms having deodorizing ability are supported on these carriers.

[0071] As a viscosity-imparting organism that generates fucoidan, which is a viscous component, as the biological type carrier, for example, brown algae can be adopted. Examples of brown algae that can be used include kombu, wakame, mekabu, mozuku, hiziki, nori, which are used for food, as well as akamoku and hon-dawara of marine driftwood, but are not limited thereto.

[0072] FIG. 4 is a schematic diagram showing a configuration example of the biological deodorizing apparatus 100 according to the third embodiment. In the example shown in FIG. 4, the packing layer 5 has a first sublayer 51 (first sub-carrier layer 51), a main layer 52 (main carrier layer 52), and a second sublayer 53 (second sub-carrier layer 53) in order from the liquid tank 6 side. The first sublayer 51, the main layer 52, and the second sublayer 53 support the carrier by, for example, a mesh container. For the main layer 52 located in the middle, a viscosity-imparting organism that produces a viscous component (e.g., fucoidan), such as brown algae, is employed as a biological carrier.

[0073] As a result of experiments, it has been confirmed that brown algae have an excellent effect of generating air bubbles and maintaining an air bubble layer.

[0074] The first sub-layer 51, the main layer 52, and the second sub-layer 53 may each be held in an individual mesh container, but they may also be partitioned and accommodated in one storage container by a net made of plastic or the like.

[0075] Brown algae contain relatively more potassium among the three major nutrients of organisms, nitrogen, potassium, and phosphorus, but have low contents of nitrogen and phosphorus. Therefore, in the initial stage of using a carrier using brown algae, even if sufficient deodorizing performance is exhibited, the deodorizing performance may gradually deteriorate due to long-term use (e.g., for several years). For the purpose of supplementing the nutrients (nitrogen, phosphorus) with low contents and assisting the healthy (active) survival of viscous organisms, organisms rich in nitrogen and phosphorus (hereinafter sometimes referred to as auxiliary organisms), such as gramineous plants, cyperaceous plants, and herbs, are adopted as carriers, which can contribute to the preservation of the deodorizing function over a long period.

[0076] As gramineous plants, for example, rice straw, rush, miscanthus, eelgrass, chigaya, Japanese millet, pampas grass, etc., as cyperaceous plants, for example, bulrush, Japanese bulrush, kangaroo grass, kusai, kogomei, bluekougaize kishou, kougaize kishou, hanabize kishou, himekougaize kishou, tachikougaize kishou, doro-i, etc., as herbs, great valerian, great bindweed, great mugwort, noginasiseiban corn, memamatsuyoigusa, bulrush, etc. can be used. For example, gramineous plants can be adopted as the first sub-layer 51, and herbs can be adopted as the second sub-layer 53 as biological carriers.

[0077] The rush grass adopted as the biological carrier has not shown any signs of compaction even after one year, and it has been confirmed that its filled height maintains the initial height. From this, it can be understood that rush grass has a lifespan of several years as a biological carrier and is excellent from the perspective of durability. The biological carrier can be used in other embodiments, but rush grass is particularly preferably usable.

[0078] Thus, the viscosity-imparting organisms and auxiliary organisms are easily available and are materials derived from organisms, so the filling layer 5 can be easily and safely configured.

[0079] In the above example, the configuration with the main layer 52 located in the middle is shown, but it is not limited to this configuration and can be appropriately changed.

[0080] FIG. 5 is a diagram for explaining the removal effect (deodorization effect) of odor components of the biological deodorization device 100 using a biological carrier in the filling layer 5. FIG. 5(A) shows the relationship between the height (H) of the bubble layer BL in the filling layer 5 and the removal rate, and FIG. 5(B) shows the relationship between the height (H) of the bubble layer BL in the filling layer 5 and the pressure loss of the filling layer 5. As the configuration of the filling layer 5, rice straw with a height of 15 cm was adopted as the first sublayer 51, akamoku with a height of 5 cm was adopted as the main layer 52, and rush grass with a height of 10 cm was adopted as the second sublayer 53, and the removal rate of the odor components of the gas G was measured using a filling layer 5 with a total height of 30 cm.

[0081] By adding fucoidan derived from brown algae akamoku as a viscous component from the filling layer 5 to the liquid 7, it is possible to strengthen the foam film of the bubbles B and form the bubble layer BL. As shown in FIG. 5(A), a very high removal rate can be achieved even when using a biological carrier, and it can be understood that the removal rate increases as the height of the bubble layer BL increases. Also, as shown in FIG. 5(B), it can be understood that the pressure loss also increases as the height of the bubble layer BL increases. However, the pressure loss is very slight and substantially has no influence on the load of the blower 4.

[0082] Also, the superficial velocity of the gas G flowing into the deodorizing tower 1 was changed, and the superficial velocity dependence of the removal rate was investigated. As a result, it was confirmed that the highest removal efficiency can be obtained when the superficial velocity LV of the gas G in the deodorizing tower 1 is in the range of 0.15 to 0.175 [m / s], and the superficial velocity within this range can be preferably adopted.

[0083] In this way, since the packing layer 5 itself constitutes the viscosity-imparting mechanism without providing an independent viscosity-imparting mechanism, the configuration of the biological deodorizing apparatus 100 can be further simplified.

[0084] Note that the packing layer 5 does not necessarily have to be configured in three layers. It is sufficient to include the main layer 52 containing a viscosity-imparting organism capable of imparting at least a viscous component as a carrier, and it may also be configured with only the main layer 52. However, for the long-term stable operation of the biological deodorizing apparatus 100, the packing layer 5 containing a viscosity-imparting organism that generates a viscous component (fucoidan) and an auxiliary organism that assists the viscosity-imparting organism is preferably adopted. For example, a combination of the main layer 52 and the first sub-layer 51, or a combination of the main layer 52 and the second sub-layer 53 may be used. The stacking order of the main layer 52, the first sub-layer 51, and the second sub-layer 53 is arbitrary and is not limited to the example shown in FIG. 4.

[0085] Note that as a result of experiments, it has been confirmed that the configuration in which the main layer 52 using brown algae as the viscosity-imparting organism is arranged at the uppermost stage has the highest stable generation effect of the bubble layer. In this case, from the upper stage in order, a configuration of the main layer 52, the second sub-layer 53, and the first sub-layer 51 can be adopted, or a two-layer configuration of the main layer 52, the first sub-layer 51 or the main layer 52, the second sub-layer 53 can also be adopted.

[0086] The structure of the filling layer 5 may be a laminate of a layer containing a viscosity-imparting organism and a layer containing an auxiliary organism, or may be a layer containing a mixture of a viscosity-imparting organism and an auxiliary organism. From the perspective of work efficiency of maintenance, etc., the structure of the filling layer 5 can be arbitrarily selected. For example, it can be configured as a laminate of a layer containing a viscosity-imparting organism (main layer 52) and a layer containing an auxiliary organism (first sub-layer 51, second sub-layer 53), and the periods of regular maintenance and regular replacement can be made different for each layer.

[0087] (Embodiment 4) The location where the viscosity-imparting mechanism using the above viscosity-imparting organism is provided is not limited to within the filling layer 5, and may be provided in the liquid tank 6 or the circulation mechanism that circulates the liquid 7. FIG. 6(A) is a schematic diagram for explaining a configuration example of the biological deodorization device 100 provided with a viscosity-imparting mechanism using a viscosity-imparting organism in the liquid tank 6, and FIG. 6(B) is a schematic diagram for explaining a configuration example of the biological deodorization device 100 provided with a viscosity-imparting mechanism in the circulation mechanism. For visibility, the pH value adjustment mechanism and the liquid supply mechanism are omitted.

[0088] As shown in FIG. 6(A), the biological deodorization device 100 includes a viscosity-imparting organism accommodation part 37 that accommodates a viscosity-imparting organism in the liquid tank 6. The viscosity-imparting organism accommodation part 37 is configured by a container having a wire mesh or a plastic mesh at least partially so that the liquid 7 can flow in and out. Inside the viscosity-imparting organism accommodation part 37, a viscosity-imparting organism that generates a viscous component as described in Embodiment 3 is accommodated. Further, the viscosity-imparting organism accommodation part 37 may further accommodate an auxiliary organism for assisting the survival of the viscosity-imparting organism.

[0089] The viscous component generated by the viscosity-imparting organism in the viscosity-imparting organism accommodation part 37 is mixed with the liquid 7, and the viscosity of the liquid 7 can be increased. As a result, the strength of the bubble film of the bubbles of the liquid 7 can be increased, the growth of the bubble layer BL can be promoted, and the deodorization efficiency of the biological deodorization device 100 can be improved. In this case, the bioadhesive-imparting organisms and auxiliary organisms in the bioadhesive-imparting organism accommodating portion 37 function as a bioadhesive-imparting mechanism, but do not necessarily function as a biological carrier.

[0090] In FIG. 6(A), the bioadhesive-imparting organism accommodating portion 37 is disposed at the bottom of the liquid tank 6, but is not necessarily limited thereto, and may be separated from the bottom of the liquid tank 6 and disposed between the bottom of the liquid tank 6 and the liquid surface of the liquid 7. By separating from the bottom of the liquid tank 6, it is possible to eliminate the influence of unnecessary foreign matters or the like that may accumulate at the bottom of the liquid tank 6.

[0091] Further, the bioadhesive-imparting organism accommodating portion 37 may be held by being sandwiched between a net partition plate (or partition net) such as plastic in the liquid tank 6.

[0092] Further, the arrangement location of the bioadhesive-imparting organism accommodating portion 37 is not limited to the example of being disposed in the liquid tank 6. The bioadhesive-imparting organism accommodating portion 37 constituting the bioadhesive-imparting mechanism may be provided in the circulation mechanism. For example, as shown in FIG. 6(B), the bioadhesive-imparting organism accommodating portion 37 may be disposed in the middle of the third pipe 11 through which the liquid 7 circulates or a branch pipe 111 branched from the third pipe 11. The bioadhesive-imparting organism accommodating portion 37 can impart a viscous component to the liquid 7 circulating in the third pipe 11 or the branch pipe 111. By such an arrangement of the bioadhesive-imparting organism accommodating portion 37, the circulation mechanism can be provided with the function as a bioadhesive-imparting mechanism. Compared with the configuration in which the bioadhesive-imparting organism accommodating portion 37 is disposed in the liquid tank 6 as shown in FIG. 6(A), the maintenance of the bioadhesive-imparting organism accommodating portion 37 becomes easier. For example, the bioadhesive-imparting organisms or auxiliary organisms in the bioadhesive-imparting organism accommodating portion 37 can be periodically replaced.

Industrial Applicability

[0093] The biological deodorization device according to the present invention can greatly improve the deodorization efficiency by microorganisms, can also handle deodorization of odorous gases containing high-concentration odor components, and can be miniaturized compared with conventional biological deodorization devices. In addition, it is possible to control the deodorization efficiency, which was difficult with conventional biological deodorization devices. It can be widely adopted as a deodorization device for odorous gases, and has great industrial applicability.

Explanation of Signs

[0094] 100 Biological deodorization device 1 Deodorization tower 2 Gas inlet 3 First pipe (gas introduction section) 4 Blower (air blower) 5 Packing layer 51 First sublayer (first sub-carrier layer) 52 Main layer (main carrier layer) 53 Second sublayer (second sub-carrier layer) 6 Liquid tank (circulation liquid tank) 7 Liquid (circulation liquid) 8 First discharge port (circulation liquid discharge port) 9 Second pipe 10 Pump (circulation pump) 11 Third pipe (circulation pipe) 111 Branch pipe 12 Inlet 13 Liquid discharge part (spray nozzle) 14 Gas discharge part 15 Outlet (gas discharge port) 16 Discharge pipe 17 Valve 18 Chemical tank 19 Pump (delivery pump) 20 Fourth pipe 21 Neutralizing liquid tank 22 Pump (neutralizing pump) 23 Fifth pipe 24 Liquid tank (water tank) 25 Pump (supply pump) 26 Sixth pipe 28 Gas discharge port (exhaust port) 29 Gas-liquid separator (demister) 30 Air supply pump (air pump) 31 Bubble generation nozzle (bubbling nozzle) 32 Seventh pipe 33 Control device (controller) 34 Sensor 35 Eighth pipe 36 Measuring instrument 37 Viscosity-imparting biological containment section B Bubbles BL Bubble layer G Process gas (odor gas)

Claims

1. A biological deodorization device for deodorizing odorous gas by microorganisms, a packed bed (5) for accommodating a carrier carrying the microorganisms, a liquid tank (6) for holding a liquid (7) supplied to the packed bed (5), and a bubble layer generation mechanism for generating bubbles (B) in the liquid (7) in the liquid tank (6) to form a bubble layer (BL) on the liquid tank (6), wherein the liquid (7) has viscosity by containing a viscous component, the bubble layer generation mechanism grows the bubble layer (BL) to the inside of the packed bed (5), the packed bed (5) is installed above the liquid tank (6), and the odorous gas is configured to pass through the packed bed (5). A biological deodorization device characterized by this.

2. The biological deodorization device according to claim 1, wherein the height of the bubble layer (BL) in the packed bed (5) is controlled according to the concentration of the odor component of the odorous gas by the bubble layer generation mechanism.

3. The biological deodorization device according to claim 1 or 2, wherein the viscous component is a biologically-derived viscous substance.

4. The biological deodorization device according to claim 1 or 2, wherein the viscous component is polyvinyl alcohol, a methylcellulose-based thickener, sodium alginate, starch, or fucoidan.

5. The biological deodorization device according to claim 1 or 2, wherein the liquid is mainly composed of water and does not harm the survival and deodorization of the microorganisms, and the viscous component does not harm the survival and deodorization of the microorganisms.

6. The odorous gas is a gas generated in a livestock manure treatment plant or a sewage treatment plant, and the microorganisms are microorganisms that decompose the odorous gas. The biological deodorization device according to claim 1 or 2.

7. The biological deodorization device according to claim 1, wherein the packed bed (5) accommodates a viscosity-imparting organism that generates a viscous substance as the viscous component.

8. The biological deodorization device according to claim 7, wherein the packed bed (5) accommodates an auxiliary organism that supplies nutrients to assist the survival of the viscosity-imparting organism.

9. The packed bed (5) has a main carrier layer (52) configured with the viscosity-imparting organism as a carrier and sub-carrier layers (51, 53) configured with the auxiliary organism as a carrier, and the main carrier layer (52) is disposed above the sub-carrier layers (51, 53). The biological deodorization device according to claim 8, characterized by this.

10. The auxiliary organism is selected from Gramineae plants, Cyperaceae plants, and herbs, and the viscosity-imparting organism is brown algae. The biological deodorization device according to claim 8 or 9, characterized in that.

11. It has a gas introduction part (3) for introducing the odorous gas into the packing layer (5), The gas introduction part (3) has a gas discharge port (15), The gas discharge port (15) is located below the liquid level of the liquid (7) in the liquid tank (6), The gas introduction part (3) constitutes the bubble layer generation mechanism. The biological deodorization device according to claim 1 or 2, characterized in that.

12. The bubble layer generation mechanism has an air supply pump (30) and a bubble generation nozzle (31) connected to the air supply pump (30), The air supply pump (30) supplies air or the odorous gas to the bubble generation nozzle (31), The bubble generation nozzle (31) is located below the liquid level of the liquid (7) in the liquid tank (6). The biological deodorization device according to claim 1 or 2, characterized in that.

13. The biological deodorization device further includes a sensor (34) for detecting the concentration of the odorous gas and a control device (33), When the control device (33) detects an increase in the odor component concentration of the odorous gas, it increases the exhaust volume of the air supply pump (30), and when it detects a decrease in the odor component concentration, it decreases the exhaust volume of the air supply pump (30). The biological deodorization device according to claim 12, characterized in that.

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