JP5198735B2 - Method and apparatus for removing malodorous components in malodorous gas - Google Patents

Description

  The present invention relates to a method for biological deodorization of malodorous gas using microorganisms that decompose malodorous components. More particularly, the present invention relates to a more effective biological deodorization method and apparatus when the malodorous component is a volatile organic compound (VOC) such as toluene, xylene and benzene.

  A biological deodorization method for removing malodorous components by circulating malodorous gas through a biological deodorization tower in which microorganisms that decompose malodorous components are immobilized has been widely known. Such biological deodorization methods include, for example, a hydrogen sulfide-containing gas in a packed bed supporting hydrogen sulfide-decomposing microorganisms, a packed bed supporting methyl mercaptan-decomposing microorganisms, and a packed bed supporting methyl sulfide-decomposing microorganisms. A method for removing sulfur-based malodorous components such as hydrogen sulfide is known (for example, see Patent Document 1).

  This method has a certain effect for removing water-soluble malodorous components such as hydrogen sulfide. However, sufficient effects cannot be obtained when the malodorous component is a volatile organic compound such as toluene, xylene and benzene. The biological deodorization method is a method for deodorizing malodorous gas by dissolving malodorous components in the malodorous gas in the aqueous phase and decomposing them by microorganisms present in the aqueous phase. On the other hand, the removal rate of water-insoluble malodorous components is limited by the dissolution rate and solubility in water. Therefore, for example, it cannot be applied to malodorous gas containing a lot of water-insoluble malodorous components such as volatile organic compounds generated from an automobile painting booth or the like.

  As a method for solving the above-described problem relating to the biological deodorization method, a method using a dissolution accelerator such as octane, decane, and hexadecane that promotes dissolution of a volatile organic compound in water is known (for example, (See Patent Document 2). However, when the above-mentioned dissolution promoter, which is an organic solvent, is mixed in the microorganism liquid, the organic solvent is mixed into the air treated by the microorganism, or the organic solvent adheres to the biological deodorization apparatus and is cleaned. There is a problem that labor is sometimes required and the microbial solution cannot be easily disposed because the organic solvent is mixed in the microbial solution.

Furthermore, as a technique for decomposing malodorous components in the air using microorganisms, a technique is known in which a microbial solution containing microorganisms that decompose the components in the paint is allowed to flow down on the walls of the paint booth used for painting with paint. (For example, refer to Patent Document 3). Although this method can have a certain effect on the decomposition of volatile organic compounds used as paints, there is still room for study from the viewpoint of decomposing volatile organic compounds in the air with high efficiency. Yes.
Japanese Patent Laid-Open No. 3-161019 Japanese Patent Laid-Open No. 10-328 Japanese Patent No. 3445587

  The present invention provides a method and an apparatus that can easily and stably provide an excellent deodorizing effect against malodorous gases containing volatile organic compounds such as toluene, xylene and benzene as malodorous components.

When culturing microorganisms in a liquid, the microorganisms do not grow and decrease on the contrary when a certain amount of time has elapsed since the start of the culture. However, the microorganism grows again by diluting the liquid. The present invention has been made based on such knowledge.

  The present invention maintains a malodorous gas containing a malodorous component and a gas, a microorganism solution containing a microorganism that decomposes the malodorous component and an aqueous medium, and the growth state of the microorganism in the microorganism fluid is maintained in a logarithmic growth phase. Provided are a method and an apparatus for contact while touching.

  According to the malodorous component removal method of the present invention, the malodorous gas containing the malodorous component and the gas, and the microorganism liquid containing the microorganism that decomposes the malodorous component and the aqueous medium in the gas-liquid contact portion. The malodorous component is removed from the malodorous gas by controlling the viable count of microorganisms in the microorganism so that the microorganisms grow logarithmically in the microorganism. Even if it is the malodorous component, the outstanding deodorizing effect with respect to malodorous gas can be acquired simply and stably.

  In the method of removing malodorous components of the present invention, when a microbial liquid is supplied to the gas-liquid contact portion, and the malodorous gas and the microbial liquid are circulated in the gas-liquid contact portion and brought into gas-liquid contact, the odorous gas is excellent. The deodorizing effect is more effective from the viewpoint of obtaining a low cost, and when the malodorous gas and the microorganism liquid are made to flow in opposite directions to each other in the gas-liquid contact portion and brought into gas-liquid contact with each other, the malodorous gas removal rate is improved. It is even more effective from the viewpoint of enhancing.

  In the malodorous component removal method of the present invention, when the microorganism liquid is circulated with respect to the gas-liquid contact portion, it is more effective from the viewpoint of easily obtaining an excellent deodorizing effect on the malodorous gas. When the supply amount of the malodorous gas supplied to the contact portion is Q kg / min, when Q-50Qkg of the microbial liquid is circulated to the gas-liquid contact portion, an excellent deodorizing effect on the malodorous gas can be simplified. It is even more effective from the viewpoint of obtaining it at low cost.

  In the malodorous component removal method of the present invention, the microbial liquid is partially added to the aqueous medium so that the same amount of the aqueous medium as the amount of the microbial liquid in the circulatory system of the microbial liquid is supplied in 2 to 14 days. If the number of viable microorganisms in the microbial solution is controlled by substitution, it is more effective from the viewpoint of easily and stably obtaining an excellent deodorizing effect against malodorous gas.

  In the malodorous component removal method of the present invention, the number of living microorganisms in the microorganism solution is measured, and the microorganism solution is diluted with an aqueous medium when the number of living microorganisms exceeds a predetermined value. Controlling the number of viable microorganisms is more effective from the viewpoint of stably obtaining an excellent deodorizing effect against malodorous gas.

  Further, in the method for removing malodorous components of the present invention, the chromaticity of the microbial liquid is measured, and when the chromaticity is 10 to 500 degrees, the microbial liquid is diluted with an aqueous medium and the number of viable microorganisms in the microbial liquid is determined. Is more effective from the viewpoint of easily and stably obtaining an excellent deodorizing effect against malodorous gas.

  In the malodorous component removal method of the present invention, the malodorous component is one or more volatile organic compounds selected from the group consisting of toluene, xylene and benzene, and the microorganism contains a volatile organic compound. From the viewpoint of obtaining an excellent deodorizing effect against malodorous gases containing volatile organic compounds as malodorous components, if the microorganisms in the activated sludge are made to adapt to the volatile organic compounds by passing the gas to the activated sludge It is effective.

According to the malodorous component removal apparatus of the present invention, the apparatus has a microorganism liquid tank, a gas-liquid contact portion, an aqueous medium supply apparatus, and a microorganism liquid discharge apparatus, and the number of living microorganisms in the microorganism liquid is logarithmic growth of microorganisms. Since the viable count of microorganisms in the microbial fluid is controlled so that it is maintained within the range of viable counts during the season, even if the malodorous component is a water-insoluble malodorous component, it has an excellent deodorizing effect on malodorous gases Can be obtained easily and stably.

  In the malodorous component removal apparatus of the present invention, the gas-liquid contact portion includes a casing, a gas-liquid contact material, and a microbial liquid supply device that supplies microbial liquid to the upper portion of the gas-liquid contact material. It is a member to which malodorous gas is supplied from the lower part of the material, and when the microbial liquid that has come into contact with the malodorous gas at the gas-liquid contact portion is returned to the microbial liquid tank, it is further from the viewpoint of obtaining an excellent deodorizing effect on the malodorous gas at a low cost. It is effective.

  In the malodorous component removal apparatus of the present invention, a predetermined amount of aqueous medium is supplied to the microbial liquid tank by the aqueous medium supply device at a predetermined interval or speed, and a predetermined amount of microbial liquid is supplied to the microbial liquid by the microbial liquid discharge device. Further having a supply / drain time control device for discharging from the tank is more effective from the viewpoint of easily and stably obtaining an excellent deodorizing effect against malodorous gas.

  Alternatively, in the malodorous component removing apparatus of the present invention, an optical property measuring device that measures the optical properties of the microbial fluid in the microbial fluid tank, and an aqueous medium supply according to the optical properties of the microbial fluid measured by the optical property measuring device When the apparatus further includes an optical property control device that supplies the aqueous medium to the microbial liquid tank by the apparatus and discharges the microbial liquid from the microbial liquid tank by the microbial liquid discharge apparatus, the excellent deodorizing effect against malodorous gas can be easily and stably performed. It is more effective from the viewpoint of obtaining.

  In the malodorous component removal apparatus of the present invention, the optical property measuring device is a device that measures the chromaticity of the microbial fluid in the microbial fluid tank, and the optical property control device has a measured value of the chromaticity of the microbial fluid that is predetermined. When the aqueous medium supply device supplies the aqueous medium to the microbial liquid tank and the microbial liquid discharge device discharges the microbial liquid from the microbial liquid tank, the excellent deodorizing effect against malodorous gas can be easily and It is more effective from the viewpoint of obtaining stably.

<Method for removing malodorous components>
The method of the present invention removes malodorous components from the malodorous gas by bringing the malodorous gas and the microorganism liquid into gas-liquid contact at the gas-liquid contact portion. In the present invention, it is preferable that the microbial solution is repeatedly brought into contact with the malodorous gas while controlling the number of living microorganisms in the microbial solution. Such contact between the microbial liquid and the malodorous gas is, for example, supplying the malodorous gas and the microbial liquid in the microbial liquid tank to the gas-liquid contact portion disposed outside the microbial liquid tank that contains the microbial liquid. It can be performed by collecting the microbial liquid after contact with the gas and liquid in the microbial liquid tank, or by dispersing malodorous gas in the microbial liquid accommodated in the microbial liquid tank.

  The malodorous gas contains a malodorous component and a gas. The malodor component is not particularly limited as long as it is a substance that causes malodor. Examples of the malodorous component include known components having water solubility or water insolubility and volatility. In particular, the present invention is excellent in removing water-insoluble malodorous components, and therefore can be applied to removing such components. Examples of the malodorous component include volatile organic compounds, and examples of the volatile organic compound include toluene, xylene, and benzene. The malodorous component contained in the malodorous gas may be one type of component or two or more types of components.

  The gas is not particularly limited, but is preferably a gas inert to the microbial fluid. Examples of the gas include air, nitrogen gas, carbon dioxide gas, and rare gas.

The concentration of the malodorous component in the malodorous gas varies depending on the type of malodorous component and the form of gas-liquid contact, but is preferably 2,000 ppm or less, more preferably 1,000 ppm or less, and 500 ppm or less. More preferably, it is 250 ppm or less. If the concentration is higher than 2,000 ppm, the malodorous component may not be sufficiently removed from the malodorous gas. In addition, the concentration varies depending on the type of malodorous component and the type of microorganism, etc., but from the viewpoint of maintaining the ability to remove malodorous components of microorganisms in the microorganism liquid and supporting stable growth of microorganisms in the microorganism liquid, It is preferable that it is 10 ppm or more.

  The concentration of the malodorous component in the malodorous gas can be measured, for example, by a known measuring device such as a detector tube or a gas chromatography device, and can be adjusted by processing the malodorous gas with a deodorizing device.

  The microorganism liquid contains a microorganism that decomposes the malodorous component and an aqueous medium. The microorganism is not particularly limited as long as it can decompose malodorous components, and may be one kind of microorganism or two or more kinds of microorganisms. In addition, when two or more kinds of microorganisms are included, microorganisms that cannot decompose the malodorous component may be included as long as the malodorous component can be sufficiently removed.

  The microbial fluid can be obtained by actively administering the specific microorganism to the aqueous medium, or by performing an appropriate operation without actively administering the specific microorganism to the aqueous medium. be able to. For example, the microbial fluid can be obtained by administering a microorganism acclimatized to the malodorous component to the aqueous medium, or by administering a microorganism not accustomed to the malodorous component to the aqueous medium and then acclimatizing the microorganism to the malodorous component. It can also be obtained by continuously contacting the malodorous gas with the aqueous medium and collecting the microorganisms in the malodorous gas accustomed to the malodorous component in the aqueous medium. It is obtained by continuously contacting a gas such as gas or outside air with an aqueous medium, collecting microorganisms in the gas not accustomed to the malodorous component in the aqueous medium, and further acclimatizing the microorganism to the malodorous component. You can also.

  As the microorganism, a microorganism adapted to the malodorous component by supplying a malodorous component or malodorous gas to the activated sludge can be suitably used. For example, various microorganisms exist in activated sludge. If this activated sludge is kept in contact with any component, microorganisms that could not be adapted to any component will die, and microorganisms that prefer any component will survive (accommodate).

  The acclimatization of microorganisms is preferably performed in an environment similar to the environment used for removing malodorous components. For the acclimatization of microorganisms, for example, activated sludge or a suspension of activated sludge and an aqueous medium is supplied with a malodorous gas to be treated or a gas containing a malodorous component at the same level for a suitable period of 5 to 60 days. Can be done. The acclimatization of the microorganism may be determined by, for example, measuring the number of living microorganisms and confirming that the microorganism has entered the logarithmic growth phase.

  In addition, in the case of obtaining microorganism liquid by collecting microorganisms in gas such as malodorous gas, the familiarity of microorganisms is the same as the familiarity of microorganisms in the activated sludge described above. It can be performed by contacting for an appropriate period.

As the activated sludge, normal activated sludge such as activated sludge in a sewage treatment plant or activated sludge in a kitchen wastewater treatment facility can be used. Although the said microorganisms are not specifically limited, For example, the microorganisms considered that the said volatile organic compound can be decomposed | disassembled are described also in patent 344587, for example. Such microorganisms include Zoogloea, Bucillus, Pseudomonas, Acinetobacter, Flavobacterium, Methanococcus, and Micrococcus. ) Genus, Bacterium genus, Mycobacterium genus, Acromobacter genus, Aeromonas genus or two or more.

  The aqueous medium is not particularly limited as long as it is a liquid medium containing water as a main component and the microorganism can grow when nutrients necessary for the growth of the microorganism are added. Examples of the aqueous medium include water, an aqueous solution of a water-soluble organic solvent such as alcohol and a surfactant, an aqueous solution of an inorganic salt such as a pH adjuster, and a mixture thereof.

  As the microbial solution, a suitable acclimation period is provided as necessary, so that one type of commercially available microbial solution can be used, or two or more types can be mixed and used. The viewpoint of improving the removal efficiency of malodorous components by using a microbial solution containing two or more kinds of useful microorganisms compared to a microbial solution containing only one kind of useful microorganisms. From the viewpoint of enhancing versatility and convenience in deodorizing malodorous gases.

The number of viable microorganisms in the microbial solution varies depending on the type of microorganism and the physical properties of malodorous components, but from the viewpoint of obtaining a sufficient removal effect of malodorous components, 1 × 10 ⁴ CFU / mL (CFU: Colony Forming Unit) ) Or more, preferably 1 × 10 ⁵ CFU / mL or more, and more preferably 1 × 10 ⁶ CFU / mL or more. The number of viable microorganisms in the microbial fluid can be measured by a plate culture method using a standard agar medium, or approximately measured by observing the microbial fluid with a microscope and counting the microorganisms observed in the field of view. You can also.

  The gas-liquid contact portion is a device that makes the microbial liquid contact with malodorous gas. As the gas-liquid contact portion, a known device for bringing gas and liquid into close contact, such as a device for sufficiently bringing gas into contact with the liquid, can be used. In the gas-liquid contact portion, for example, a cylindrical body such as a tower to which malodorous gas and microbial liquid are supplied, and a plurality of passages accommodated in the cylindrical body and through which malodorous gas and microbial liquid pass are formed inside the cylindrical body. And an apparatus having a gas-liquid contact material to be used. As the gas-liquid contact material, various members such as a filler, a tray, and a laminated body of corrugated plates can be used depending on the relative supply direction of the malodorous gas and the microbial liquid to the gas-liquid contact portion. .

  Or the said gas-liquid contact part can be formed using the apparatus for making the liquid absorb the component in gas. Such a gas-liquid contact portion forms a microbial liquid tank in which the microbial liquid is stored, a gas dispersion member such as an air stone that disperses the odorous gas in the microbial liquid, or a predetermined passage of the odorous gas in the microbial liquid. It can form using a member.

  The relative flow direction of the malodorous gas and the microbial liquid is not particularly limited. For example, the malodorous gas and the microbial liquid may flow in the same direction in parallel, or may flow in directions orthogonal to each other. It may also flow in the opposite direction. The relative flow direction of the malodorous gas and the microbial liquid is appropriately selected from the viewpoints of resistance due to mutual flow, the amount of circulation, and the removal efficiency of the malodorous gas. From the viewpoint of suppressing resistance due to mutual flow, it is preferable to flow the malodorous gas and the microbial liquid in the same direction in parallel, and from the viewpoint of enhancing the removal efficiency of the malodorous gas, the malodorous gas and the microbial liquid may be flowed in opposite directions. preferable.

The amount of the microbial fluid in the circulatory system of the microbial fluid including the gas-liquid contact portion, that is, the amount of the microbial fluid used in the present invention (hereinafter also referred to as the “retained liquid amount”) is the type of the gas-liquid contact portion and the gas-liquid contact. It can be determined appropriately according to the amount of malodorous gas supplied to the part. For example, in the case where a member in which the malodorous gas and the microbial fluid are in contact with each other and are in gas-liquid contact is used as the gas-liquid contact portion, the amount of microbial fluid retained is the amount of malodorous gas supplied to the gas-liquid contact portion. When Qkg / min is set, Q to 50Qkg is preferable, and Q to 5Qkg is more preferable. If the amount of microbial fluid retained exceeds 50Qkg, it will not adversely affect the removal of malodorous components, but the initial cost will increase due to the increase in the size of the microbial fluid tank. Running costs may increase due to the need to supply nutrients to the microbial fluid. If the amount of the microbial fluid retained is less than Q kg, the malodorous component may not be sufficiently removed from the malodorous gas.

  In the method of the present invention, the number of viable microorganisms in the microbial solution is controlled so that the microorganisms grow logarithmically in the microbial solution. When microorganisms are grown in a proliferative environment, the number of living microorganisms generally increases logarithmically and then becomes constant. In general, a period in which microorganisms multiply logarithmically is called a logarithmic growth phase, and a period in which the number of microorganisms thereafter is constant is called a stationary phase. The logarithmic growth phase is divided into three periods: early, middle and late.

  The number of viable microorganisms in the microbial fluid is determined by, for example, maintaining the environment in which the microorganisms can logarithmically grow in the microbial fluid, and increasing the number of microorganisms in the microbial fluid within the logarithmic growth period. By reducing the concentration of microorganisms in the microorganism liquid according to the number of viable bacteria, it is possible to control the microorganisms to grow logarithmically in the microorganism liquid.

  The environment in which microorganisms can grow logarithmically in microbial liquids is, for example, gas-liquid contact between malodorous gas and microbial liquid, supply of nutrients to microbial liquid, temperature, pH, aeration rate (oxygen concentration in microbial liquid) It can be realized by appropriately adjusting various conditions such as. Examples of nutrients include components that are usually necessary for the growth of microorganisms, such as carbon sources, nitrogen sources, inorganic ions, and other organic components.

  Reduction of the concentration of microorganisms in the microbial liquid (hereinafter also referred to as “dilution of the microbial liquid”), for example, partial sterilization of the microbial liquid, aqueous medium and nutrients in the microbial liquid (hereinafter also referred to as “aqueous medium etc.”) ), A partial replacement (substitution) of the microbial liquid by supplying the microbial liquid such as an aqueous medium, and discharging the microbial liquid. From the viewpoint of keeping the amount of the microbial solution retained constant, the dilution of the microbial solution is preferably partial replacement of the microbial solution.

  More specifically, a microorganism growth curve is obtained in advance by trial operation, model experiment, or computer simulation for removing malodorous components, and the number of living microorganisms in the microorganism solution is measured. By diluting the microbial fluid so that the numbers are in the logarithmic growth phase in the growth curve, the viable count of microorganisms in the microbial fluid can be controlled so that the microorganisms grow logarithmically in the microbial fluid. Regarding the control of the viable count of microorganisms in the microbial fluid, it is preferable to dilute the microbial fluid to the viable count of microorganisms in the early logarithmic growth phase in the late logarithmic growth phase from the viewpoint of realizing a high ability to remove malodorous components. More preferably, the microbial solution is diluted to the number of viable microorganisms in the middle of the logarithmic growth phase in the late logarithmic growth phase, and more preferably diluted so that the viable cell count in the late logarithmic growth phase is maintained. .

  Control of the number of living microorganisms in the microorganism solution may be performed based on the measured value after measuring the number of living microorganisms in the microorganism solution. Such control of the number of viable microorganisms is preferable from the viewpoint of removing malodorous components from malodorous gas efficiently, simply and stably. As described above, the number of viable microorganisms in the microbial solution can be measured by a plate culture method using a standard agar medium or by observing the microbial solution with a microscope.

  Control of the number of viable microorganisms in the microbial solution can also be performed by replacing a predetermined amount of the microbial solution with an aqueous medium or the like at a predetermined speed or interval. Such control of the number of viable microorganisms is preferable from the viewpoint of removing malodorous components from malodorous gas efficiently, simply and stably.

The speed or interval at the time of replacing the microbial fluid with an aqueous medium or the like and the replacement amount can be determined from the growth curve. The rate at which the microbial fluid is replaced with an aqueous medium or the like varies depending on the type of malodorous component or the type of microorganism, but the period during which the microbial fluid is quantitatively replaced with an aqueous medium or the like (the amount of liquid retained in microbial fluid replacement). The period during which the same amount of aqueous medium or the like is used, hereinafter also referred to as “residence time”) is preferably 2 to 14 days, and more preferably 2 to 7 days. If the residence time is too short, the microbial fluid may not grow sufficiently due to dilution of the microbial fluid, and if the residence time is too long, the time during which the growth of the microorganism is in the stationary phase or death phase becomes longer, and the malodorous component is sufficient. May not be removed.

  The interval at which the microbial solution is intermittently replaced with an aqueous medium or the like is preferably the time that is less than ½ of the residence time or 7 days or less. Moreover, it is preferable that the replacement amount per time when the microorganism liquid is intermittently replaced with an aqueous medium or the like is ½ or less of the retained liquid amount. If the interval between replacements and the amount of replacement per time are too small, the frequency of replacement increases and the running cost increases. If the replacement interval or the amount of replacement per one time is too large, the number of viable microorganisms in the microorganism solution will fluctuate greatly, and the ability to remove malodorous components may fluctuate.

  When the microbial solution is replaced with an aqueous medium or the like continuously at a predetermined rate according to the residence time, the replacement of the microbial solution is performed after the number of viable microorganisms in the microbial solution has increased sufficiently, that is, logarithmic growth. It is preferable to carry out in the middle phase, and more preferably in the late phase of the logarithmic growth phase.

  The speed or interval and amount of substitution when replacing the microbial fluid with an aqueous medium, etc., can be determined from model experiments, actual measurements such as trial operation of the odor component removal equipment, or the supply of odorous gases and nutrients by a computer and in the microbial fluid. It can also be obtained from theoretical values based on simulations on the growth of microorganisms.

  Control of the viable count of microorganisms in the microbial fluid can be performed based on the measurement value obtained by measuring the optical characteristics of the microbial fluid instead of measuring the viable count of microorganisms in the microbial fluid. Such optical characteristics can be appropriately determined according to the state of optical change of the microbial fluid. Examples of the optical characteristics include chromaticity, turbidity, and optical density [O. D. ]. The measured value of the optical properties of the microbial fluid is converted into the viable count of microorganisms in the microbial fluid using a calibration curve prepared in advance for the measured optical properties of the microbial fluid and the viable count of microorganisms in the microbial fluid. be able to. Such control of the number of viable microorganisms is also preferable from the viewpoint of efficiently, simply and stably removing the malodorous component from the malodorous gas.

  Control of the number of viable microorganisms in the microbial liquid based on the measured value of the optical characteristics of the microbial liquid can be performed by diluting the microbial liquid when the optical characteristics of the microbial liquid are a predetermined measured value. The predetermined measured value of such an optical characteristic is preferably the value of the optical characteristic of the microbial fluid in the late logarithmic growth phase, and varies depending on the type of microorganism and the state of optical change of the microbial fluid. In the deodorization of the malodorous gas by the microorganisms in the activated sludge acclimatized by the malodorous gas contained as the malodorous component, the microorganism liquid is an aqueous medium when the chromaticity of the microorganism liquid is 10 to 500 degrees, more preferably 50 to 100 degrees. By diluting with, the viable count of microorganisms in the microorganism solution can be appropriately controlled.

  In addition, when the viable count of microorganisms in the microbial fluid is controlled based on the viable count of microorganisms in the microbial fluid or the measured values of the optical properties of the microbial fluid, the measured value is the viable count in the late logarithmic growth phase. For example, a certain amount of the microbial solution may be replaced with an aqueous medium or the like. Control of the viable count of such microorganisms is also preferable from the viewpoint of simply controlling the viable count. In this case, the replacement amount of the microbial liquid is preferably, for example, ½ or less of the retained liquid amount. If the amount of substitution is too small, the running cost increases, and if the amount of substitution is too large, the viable count of microorganisms in the microbial fluid may fluctuate and the ability to remove malodorous components may fluctuate.

In the method of the present invention, various known techniques suitable for the removal of odorous components and microbial activities such as temperature adjustment, oxygen supply, nutrient supply, etc., as long as sufficient decomposition of odorous components by microorganisms is not hindered. Can be used in combination. The method of the present invention can be carried out using a known apparatus or member, but can be suitably carried out using the apparatus of the present invention shown below.

<Odor component removal device>
The apparatus of the present invention removes a microbial liquid tank containing a microbial liquid containing microorganisms that decompose malodorous components and an aqueous medium, a malodorous gas containing odorous components and gas, and a microbial liquid in the microbial liquid tank. It has a gas-liquid contact section for contacting the liquid, an aqueous medium supply device for supplying the aqueous medium to the microbial liquid tank, and a microbial liquid discharge device for discharging the microbial liquid from the microbial liquid tank. Such devices and members can be configured by combining known devices, members, and instruments as they are or as appropriate.

  The said gas-liquid contact part can be comprised with a suitable member according to the form. As a form of a gas-liquid contact part, the form provided outside a microorganisms liquid tank and the form from which a microorganisms liquid tank becomes a gas-liquid contact part are mentioned. The gas-liquid contact portion provided outside the microbial liquid tank includes a casing, a gas-liquid contact material that is accommodated in the casing and forms a passage divided in the casing, and microorganisms from above the gas-liquid contact material in the casing. And a device for supplying malodorous gas from the lower part of the gas-liquid contact material in the casing.

  The casing is not particularly limited as long as it is a member capable of forming a passage of malodorous gas and microbial liquid therein. Examples of the casing include a tower used for a gas-liquid contact absorption tower, a cylindrical body used for a chamber, a horizontally long casing, and the like.

  As the gas-liquid contact material, a member having an appropriate structure according to the relative supply direction of the microbial liquid and the malodorous gas to the gas-liquid contact portion is used. For example, in the case where the microbial liquid and the malodorous gas are supplied to the gas-liquid contact portion in the opposite direction, the gas-liquid contact material is, for example, a member composed of a plurality of corrugated plates, A corrugated sheet group stacked so that the extending direction with the groove part intersects, and when the corrugated sheet group is accommodated in the casing, at least a side of the corrugated sheet group, and the ridge part and the groove part are in the vertical direction. A member constituted by a side corrugated sheet group in which a plurality of sheets are stacked in the extending direction can be used. One or a plurality of the gas-liquid contact materials can be installed depending on conditions such as the type, contact efficiency, and pressure loss, and the gas-liquid contact materials can be used alone or in combination.

  In the case where the microbial liquid and the malodorous gas are supplied to the gas-liquid contact portion in the parallel direction (same direction), the microbial liquid and the malodorous gas are supplied from one end side (for example, the upper end side) of the casing. The gas-liquid contact material mentioned above can be used for the material.

  In the case where the microbial liquid and the malodorous gas are supplied to the gas-liquid contact portion in a direction orthogonal to each other, the malodorous gas is supplied from one side of the casing, and the gas-liquid contact material extends in all directions like a filling. A gas-liquid contact material that forms a passage can be used.

  In the case where the microbial liquid tank is used as a gas-liquid contact portion, a gas dispersion member is used for gas-liquid contact by densely dispersing gas in the liquid. The gas dispersion member includes a simple structure diffuser pipe having a plurality of holes in the pipe, an air stone, a diffuser pipe normally used for aeration in wastewater treatment, and a plurality of gas-liquid contact materials. Examples include a member having a passage. These may be used alone or in combination of two or more.

In the apparatus of the present invention, the microbial fluid that has contacted the malodorous gas at the gas-liquid contact portion is returned to the microbial fluid tank in accordance with the form of the gas-liquid contact portion. When the gas-liquid contact part is provided outside the microorganism tank, the microorganism liquid is supplied from the microorganism liquid tank to the gas-liquid contact part and returned from the gas-liquid contact part to the microorganism liquid tank. The reflux of the microbial solution from the gas-liquid contact unit to the microbial solution tank can be realized by, for example, a configuration in which an apparatus for supplying the microbial solution flowing down the gas-liquid contact unit to the microbial solution tank is provided.

  Further, when the inside of the microbial liquid tank is used as a gas-liquid contact portion, when the gas dispersion member having a plurality of gas-liquid passages such as the gas-liquid contact material is set in the microbial liquid of the microbial tank, a bad odor is generated. As convection of the microbial liquid to the gas-liquid contact part occurs as the gas flows in the gas-liquid contact part, the microbial liquid that has contacted the malodorous gas in the gas-liquid contact part is returned to the microbial liquid tank, and the microorganisms in the microbial liquid tank The liquid circulates with respect to the gas-liquid contact part.

  Including the above case, the circulation of the microbial liquid when the inside of the microbial liquid tank is used as the gas-liquid contact portion may be continuous, or by performing the circulation for a predetermined time at a predetermined interval. It may be an intermittent circulation.

  In the apparatus of the present invention, the number of living microorganisms in the microorganism solution is controlled so that the number of living microorganisms in the microorganism solution is maintained within the range of the number of living bacteria in the logarithmic growth phase of the microorganism. Although the control of the viable cell count may be performed manually by an operator, the apparatus of the present invention sets the viable cell count of the microorganism in the microorganism liquid to a predetermined value (that is, within the range of the logarithmic growth phase of the microorganism). It is preferable to further have a configuration that can be automatically controlled below the number of viable bacteria from the viewpoint of simply and stably removing malodorous components in the malodorous gas. As a configuration capable of automatically controlling the viable count of microorganisms in the microbial solution, there is a water supply / drainage time control device capable of controlling partial replacement of the microbial solution in the microbial solution tank with the aqueous medium by time.

  The water supply / drainage time control device supplies a predetermined amount of the aqueous medium to the microbial liquid tank by the aqueous medium supply device at a set interval or speed, and discharges the predetermined amount of the microbial liquid from the microbial liquid tank by the microbial liquid discharge device. If it is an apparatus, it will not specifically limit. In such a water supply / drainage time control device, a normal control device that has a built-in timer and can control the opening and closing of the valve and the operation of the pump can be used. As described above in the method of the present invention, the set time or set speed and the set value of the microbial fluid replacement amount can be determined appropriately.

  In addition, as a configuration capable of automatically controlling the number of viable microorganisms in the microbial fluid, a configuration capable of controlling partial replacement of the microbial fluid in the microbial fluid tank with the aqueous medium based on the measured value of the microbial fluid. Is mentioned. As such a configuration, for example, an optical property measuring device for measuring the optical properties of the microbial fluid in the microbial fluid tank, and an aqueous medium by the aqueous media supply device according to the optical properties of the microbial fluid measured by the optical property measuring device. And an optical characteristic control device that discharges the microbial fluid from the microbial fluid tank by the microbial fluid discharge device.

  The optical property measuring device is not particularly limited as long as it is a device that can measure optical properties such as chromaticity and turbidity of a microbial fluid. The optical property control device can be appropriately determined according to the state of optical change of the microbial fluid. For example, in the case of a device that measures the chromaticity of the microbial fluid in the microbial fluid tank, the optical property control device uses the aqueous medium supply device when the measured value of the chromaticity of the microbial fluid reaches a predetermined optical property value. The aqueous medium may be supplied to the microbial liquid tank, and the microbial liquid may be discharged from the microbial liquid tank by the microbial liquid discharging device.

As the optical property measuring apparatus, a known apparatus can be used, and examples thereof include a chromaticity meter manufactured by Nippon Denshoku Industries Co., Ltd., WA System, a turbidimeter manufactured by Optex Co., Ltd., and a turbidity checker. As the optical characteristic control device, a normal control device capable of controlling the opening / closing of the valve and the operation of the pump by feedback control can be used. As described above in the method of the present invention, the set value of the optical characteristic value and the set value of the replacement amount of the microbial fluid can be appropriately determined. In the measurement of the optical characteristics of the microbial liquid by the optical characteristic measuring apparatus, the microbial liquid itself may be used, but the microbial liquid diluted appropriately according to the equipment to be used is used. It may be measured.

  Hereinafter, the present invention will be described in more detail with reference to the drawings.

<First embodiment>
As shown in FIG. 1, the apparatus according to the present embodiment includes a microbial liquid tank 1 in which a microbial liquid is stored, a gas-liquid contact portion 2 for bringing the microbial liquid and malodorous gas into gas-liquid contact, and a microbial liquid. A water supply flow path 3 and a pump 4 that are water-based medium supply devices for supplying water to the tank 1; a microbial liquid discharge flow path 5 that is a microbial liquid discharge device for discharging microbial liquid from the microbial liquid tank 1; And a pump 6.

  The microorganism liquid tank 1 is, for example, a sealed tank. The gas-liquid contact part 2 is comprised by the casing 2a whose cross-sectional shape is a rectangle, and the gas-liquid contact material 2b which forms a some channel | path in the casing 2a. Further, the water supply channel 3 is connected to a nutrient tank for microorganisms (not shown), and the apparatus of the present embodiment can supply a desired amount of nutrients to the microorganism liquid tank 1 continuously or intermittently. It is configured as follows.

  The microbial liquid tank 1 is connected to a microbial liquid supply channel 7 for supplying the microbial liquid stored in the microbial liquid tank 1 to the gas-liquid contact portion 2. The microorganism liquid supply channel 7 is provided with a pump 8. The base end of the microbial liquid supply flow path 7 is disposed in the lower part of the microbial liquid tank 1, and the tip of the microbial liquid supply flow path 7 is disposed above the gas-liquid contact material 2b and in the upper part of the casing 2a. . An injection nozzle 9 for diffusing and injecting the microbial liquid toward the gas-liquid contact material 2b is provided at the tip of the microbial liquid supply flow path 7.

  A malodorous gas supply channel 10 for supplying malodorous gas into the casing 2a is connected to the lower part of the casing 2a. Connected to the bottom of the casing 2a is a microbial solution reflux passage 11 for returning the microbial solution flowing down in the casing 2a to the microbial solution tank 1. A pump 12 is provided in the microbial fluid reflux channel 11. Further, a processing air discharge passage 13 for discharging air processed in the casing 2a from the casing 2a is connected to the top of the casing 2a. A blower 14 is provided downstream of the processing air discharge passage 13. By exhausting the processing air from the gas-liquid contact portion 2 by the blower 14, the inside of the gas-liquid contact system becomes negative pressure.

  For example, as shown in FIG. 2, the gas-liquid contact material 2 b includes a corrugated sheet group 15 a formed by overlapping a plurality of corrugated sheets so that the extending directions of the protrusions and the grooves of the corrugated sheet intersect. And side corrugated sheet groups 15b and 15c in which a plurality of ridges and grooves are overlapped in the vertical direction on both sides of the corrugated sheet group 15a.

The microorganism liquid is a liquid containing, for example, microorganisms, water, and nutrients, and 1 to 5 L is accommodated in the microorganism liquid tank 1. The microorganism is a microorganism acclimatized by aerating air containing 200 ppm of volatile organic compounds such as toluene, xylene and benzene to the activated sludge of a sewage treatment plant at room temperature for 3 days. The number of viable microorganisms in the initial microorganism solution is, for example, 10 ⁶ to 10 ⁷ CFU / mL. The temperature of the microbial solution in the microbial solution tank 1 is maintained at about room temperature (25 ° C.) by, for example, circulating a heat medium through a jacket (not shown) or by an electric heater (not shown).

When the pump 8 is operated, the microbial liquid in the microbial liquid tank 1 is supplied to the gas-liquid contact material 2b through the microbial liquid supply channel 7 and the injection nozzle 9, and flows down the gas-liquid contact material 2b. When the pump 12 is operated, the microbial liquid is returned from the gas-liquid contact portion 2 to the microbial liquid tank 1 through the microbial liquid reflux channel 11. In this way, the microbial fluid circulates with respect to the gas-liquid contact portion 2.

  On the other hand, from the malodorous gas supply channel 10, for example, air containing a volatile organic compound as a malodorous component at a concentration of about 200 ppm is supplied as malodorous gas at a flow rate of 1 kg / min. The amount of malodorous gas supplied is adjusted by operating the blower 14.

  The circulation flow rate of the microbial liquid is appropriately adjusted according to the amount of malodorous gas supplied. For example, the time required for the microbial liquid to flow down the gas-liquid contact material 2b (gas-liquid contact time) is 0.1 to 5 seconds from the microbial liquid supply channel 7 to the gas-liquid contact material 2b via the injection nozzle 9. The microbial solution is supplied at a flow rate of 1 to 5 L / min. In addition, the said gas-liquid contact time and the flow volume of the said microorganisms liquid are the numerical values determined from the viewpoint of the practical magnitude | size of the malodorous component removal apparatus, and its cost. The gas-liquid contact time can be adjusted by the flow rate of the microbial liquid and the size and number of the gas-liquid contact material 2b.

  In the gas-liquid contact material 2b, malodorous gas flows from below to above, and microbial fluid flows from above to below. That is, the two flow in the opposite direction in the gas-liquid contact portion 2 and sufficiently contact each other. By this contact, the volatile organic compound in the malodorous gas is decomposed by the microorganisms in the microbial fluid, and about 80% of the volatile organic compound in the malodorous gas is removed from the malodorous gas. The processing air from which the volatile organic compounds have been removed is discharged from the top of the casing 2a to the processing air discharge passage 13. The microbial liquid used for the treatment of malodorous gas is supplied from the bottom of the casing 2 a to the microbial liquid tank 1 through the microbial liquid recirculation flow path 11 and the pump 12.

  On the other hand, in the microbial liquid tank 1, the number of viable microorganisms is adjusted by replacing the microbial liquid with water and nutrients. For example, 1/5 of the microbial liquid with respect to the total amount of microbial liquid (retained liquid amount) is discharged from the microbial liquid tank 1 to the microbial liquid discharge channel 5, and 1/5 of the retained liquid amount (if necessary) (Including nutrients) is supplied to the microorganism liquid tank 1 through the water supply channel 3 and the pump 4. The replacement of the microbial liquid is performed every day, and the residence time of the microbial liquid is adjusted to 2 to 14 days (for example, 5 days). By the replacement of the microbial solution, the number of viable microorganisms in the microbial solution is maintained at the number of living microorganisms in the logarithmic growth period, and the microorganisms grow logarithmically in the microbial solution. High scavenging activity is maintained.

  Examples of the nutrients include preferably the same components as the malodorous gas components, and known components such as glucose and amino acids can be used. According to various conditions such as the number of viable microorganisms and the amount of the retained liquid, the nutrient is, for example, as it is or dispersed or dissolved in water as needed, and the microorganism liquid tank is about several mg to several g per day. 1 is supplied.

  In addition, the partial replacement of the microbial fluid and the replenishment of nutrients may be performed by an operator, or the aqueous medium is supplied at a predetermined interval (for example, one day) using a control device (not shown) having a timer. The apparatus automatically supplies a predetermined amount (for example, 1/5 of the retained liquid amount) of the aqueous medium to the microbial liquid tank, and the microbial liquid discharging apparatus automatically discharges the predetermined amount of microbial liquid from the microbial liquid tank. Also good. Furthermore, regarding the microbial fluid replacement method, the microbial fluid is continuously discharged from the microbial fluid tank 1 at a rate at which 1/5 of the microbial fluid is retained from the microbial fluid tank 1 per day. The water may be continuously supplied to the microorganism liquid tank 1. In the case of continuously replacing the microbial solution, it is preferable to confirm the increase in the number of viable microorganisms in the microbial solution.

According to the present embodiment, since the microbial liquid tank 1, the gas-liquid contact unit 2, the aqueous medium supply device, and the microbial liquid discharge device are included, While the microbial liquid in which the number of living microorganisms is controlled is circulated with respect to the gas-liquid contact part 2, the gas-liquid contact part 2 can be brought into gas-liquid contact with the malodorous gas, and the malodorous gas can be efficiently removed from the malodorous gas. It can be removed easily and stably.

  In this Embodiment, it has the casing 2a and the gas-liquid contact material 2b, microbial liquid is supplied to the upper part of the gas-liquid contact material 2b in the casing 2a, and malodorous gas is supplied to the lower part of the gas-liquid contact material 2b. Since the gas-liquid contact part 2 is used, the malodorous gas and the microbial liquid can be brought into gas-liquid contact by circulating in the gas-liquid contact part 2 in opposite directions. In such gas-liquid contact, it is possible to supply the malodorous gas and the microbial liquid at the gas-liquid contact portion 2 at a lower cost than in the case where the same level of malodorous gas is processed by bubbling that supplies gas into the liquid. Is possible. Therefore, it is more effective from the viewpoint of removing malodorous components from malodorous gas at low cost.

  In the present embodiment, since a microbial liquid having a retained liquid amount of 1 to 5 times the amount of malodorous gas supplied to the gas-liquid contact portion 2 is used, microorganisms in the microbial liquid remove malodorous components. It is possible to grow microorganisms in the microorganism liquid only by supplying malodorous gas having a concentration of malodorous components as much as possible. Further, since the microbial liquid tank 1 does not have to be so large, the initial cost for the microbial liquid can be kept low. Therefore, it is much more effective from the viewpoint of easily and inexpensively removing malodorous components from malodorous gas.

  In the present embodiment, the microbial liquid is partially replaced with the aqueous medium at a predetermined interval or speed supplied in a certain period of time, and the viable count of microorganisms in the microbial liquid is controlled. Therefore, it is possible to control the viable count of microorganisms in the microbial solution so as to maintain a high ability to remove malodorous components from malodorous gas by a predetermined time and substitution amount. Therefore, it is more effective from the viewpoint of easily and stably removing the malodorous component from the malodorous gas.

  In the present embodiment, the malodorous component is a volatile organic compound, and the microorganism is a microorganism in activated sludge adapted to the volatile organic compound. Therefore, the volatile organic compound is removed with high efficiency by gas-liquid contact. be able to.

  Further, even if the malodorous component is a water-insoluble compound such as the volatile organic compound described above, the malodorous component is taken in the microorganism liquid by gas-liquid contact and then decomposed, so that the microorganism liquid in the microorganism liquid tank 1 is decomposed. Hardly contains malodorous components, and it is possible to omit the process for removing malodorous components from the microbial fluid discharged from the microbial fluid tank 1. In addition, if the microorganism is a microorganism in activated sludge, it is possible to prepare a microorganism having a desired decomposing ability for malodorous components relatively easily, and sterilization of the microorganism liquid drainage before discharging the microorganism liquid into the sewer. Processing can be omitted. Therefore, it is much more effective from the viewpoint of easily and inexpensively removing malodorous components from malodorous gas.

  In the present embodiment, the gas-liquid contact portion 2 uses one gas-liquid contact material 2b. However, a plurality of gas-liquid contact materials 2b can be used in series in the casing 2a. Arranging a plurality (for example, two or three) of gas-liquid contact materials 2b in series in the casing 2a is more effective from the viewpoint of increasing the removal efficiency of malodorous components.

  Moreover, in this Embodiment, as an apparatus which supplies the microbial liquid of the microbial liquid tank 1 to the gas-liquid contact material 2b, the injection which diffuses and injects the microbial liquid of the microbial liquid supply flow path 7 toward the gas-liquid contact material 2b Although the form using the nozzle 9 has been shown, a member that distributes and flows the microbial liquid toward the gas-liquid contact material 2b, such as a watering dish composed of a dish having a plurality of holes, may be used in the apparatus. Is possible.

<Second Embodiment>
As shown in FIG. 3, the apparatus of the present embodiment has a valve 21 that opens and closes the water supply flow path 3 and a pump (not shown) instead of the pump 4, and discharges microbial fluid instead of the pump 6. A valve 22 that opens and closes the flow path 5 is connected to a chromaticity meter 23 for measuring the chromaticity of the microbial liquid in the microbial liquid tank 1, and the chromaticity meter 23 and the valves 22 and 23. The apparatus is configured in the same manner as the apparatus shown in FIG. In the apparatus of FIG. 3, the malodorous component is removed from the malodorous gas in the same manner as in the apparatus of FIG. 1 except for the adjustment of the number of viable microorganisms in the microorganism liquid in the microorganism liquid tank 1.

  In the apparatus of FIG. 3, the chromaticity of the microbial liquid in the microbial liquid tank 1 is measured by the chromaticity meter 23. The measured value is input to the control device 24. When a predetermined measurement value up to 10 to 500 degrees (for example, 100 degrees) is input, the control device 24 opens the valve 22 to remove a predetermined amount (for example, 1/5 of the retained liquid amount) of microbial liquid. The liquid is discharged from the liquid tank 1 to the microbial liquid discharge flow path 5 and the valve 21 is opened to supply the same amount of water to the microbial liquid tank 1 through the water supply flow path 3 and the valve 21. By the replacement of the microbial solution, the growth state of the microorganism in the microbial solution is always maintained in the logarithmic growth phase, and the high removal activity of the odor component from the odor gas by the microorganism is maintained.

  In the present embodiment, the same effects as in the first embodiment can be obtained except for the effects associated with the replacement of the microbial fluid based on the time conditions.

  Further, in the present embodiment, since the chromaticity meter 23 and the control device 24 for measuring the optical characteristics of the microbial fluid are provided, the microbial fluid is replaced according to the chromaticity of the microbial fluid, and the microorganisms in the microbial fluid are replaced. By controlling the number of viable bacteria, it is possible to easily and quickly observe the actual state of microbial growth by measuring chromaticity, and diluting the microbial fluid according to the actual state of microbial growth (viable cell count) Control) is possible. Therefore, it is much more effective from the viewpoint of easily and stably removing the malodorous component in the malodorous gas.

<Third embodiment>
As shown in FIG. 4, the removal apparatus of the present embodiment further includes a gas dispersion member 30 that is set in the microbial liquid in the microbial liquid tank 1, and replaces the malodorous gas supply channel 10 with the gas dispersion member. 30 has a malodorous gas supply channel 31 and a blower 33 for supplying malodorous gas to the bottom of the processing unit 30, and instead of the processing air discharge channel 13, processing air discharge for discharging air from the gas phase in the microorganism liquid tank 1 1 except that it has a flow path 32 and does not have the gas-liquid contact portion 2, the microbial liquid supply flow path 7, the pump 8, the injection nozzle 9, the microbial liquid recirculation flow path 11, the pump 12, and the blower 14. It is configured the same as the device. In the present embodiment, the microorganism liquid tank 1 is a gas-liquid contact portion.

  For example, as shown in FIG. 4, the gas dispersion member 30 is a diffuser tube having a plurality of vent holes having a diameter of about 5 mm on the peripheral wall of the tube.

  In the apparatus of FIG. 4, the number of microorganisms in the microbial liquid is adjusted in the same manner as in the apparatus of FIG. 1 except for the gas-liquid contact between the malodorous gas and the microbial liquid.

  The malodorous gas is supplied to the gas dispersion member 30 via the blower 33 and the malodorous gas supply channel 31. The malodorous gas supplied to the gas dispersion member 30 is dispersed in the microbial liquid in the microbial liquid tank 1 through a plurality of ventilation holes in the peripheral wall, efficiently contacts with the microbial liquid, and from the odorous gas by the microorganisms in the microbial liquid. Odor components are removed.

  The processing air from which the malodorous component has been removed reaches the gas phase portion of the microbial liquid tank 1 and is discharged from the microbial liquid tank 1 to the processing air discharge passage 32.

  In the present embodiment, the same effects as in the first embodiment can be obtained except for the effects associated with the gas-liquid contact portion 2.

  Furthermore, in this embodiment, since the gas dispersion member 30 set in the microbial liquid tank 1 is used, the odor gas is supplied by supplying the odor gas into the microbial liquid, and the odor gas when the gas-liquid contact part 2 is used. It is possible to remove with high efficiency equivalent to the removal rate. In addition, since an apparatus for circulating the microbial liquid with respect to the gas-liquid contact portion 2 is unnecessary, it is further effective from the viewpoint of reducing initial cost and downsizing the apparatus.

  In the present embodiment, the configuration using one gas dispersion member 30 is shown, but it is also possible to connect a plurality of gas dispersion members 30 in series or in parallel to the malodorous gas supply channel 31. . Connecting a plurality of gas dispersion members 30 in the microorganism liquid tank 1 is more effective from the viewpoint of improving the removal efficiency of malodorous components.

<Fourth embodiment>
As shown in FIG. 5, the apparatus of the present embodiment has a valve 21 that opens and closes the water supply flow path 3 and a pump (not shown) instead of the pump 4, and discharges microbial fluid instead of the pump 6. A valve 22 that opens and closes the flow path 5 is connected to a chromaticity meter 23 for measuring the chromaticity of the microbial liquid in the microbial liquid tank 1, and the chromaticity meter 23 and the valves 22 and 23. The apparatus is configured in the same manner as the apparatus shown in FIG. Moreover, in the apparatus of FIG. 5, the malodorous component is removed from malodorous gas similarly to the apparatus of FIG. 4 except the adjustment of the number of microorganisms in the microorganism liquid in the microorganism liquid tank 1. Adjustment of the number of microorganisms in the microbial liquid in the microbial liquid tank 1 is the same as in the apparatus of FIG. 3, that is, when the chromaticity of the microbial liquid is detected by a chromaticity meter and exceeds a predetermined chromaticity, the valves 21 and 22 are adjusted. This is done by opening the valve.

  In the present embodiment, the same effects as in the third embodiment can be obtained except for the effects associated with the replacement of the microbial fluid based on the time conditions. Furthermore, in the present embodiment, the same effects as those of the second embodiment can be obtained with respect to the effects accompanying the replacement of the microbial liquid based on the conditions of the optical characteristics of the microbial liquid.

  The present invention can efficiently, easily and stably remove malodorous components from gases containing malodorous components, for example, volatile organic compounds such as toluene, xylene and benzene as malodorous components. In particular, according to the present invention, depending on the replacement of the microbial solution and the growth conditions of the microorganism, even if the odor gas treatment is resumed after the odor gas supply is stopped for about two days, a high volatile organic compound removal rate is obtained immediately after the restart. Can be realized. Therefore, the present invention can be applied to exhaust treatment at various factories such as a painting factory and a printing factory.

  Examples of the present invention are shown below, but the present invention is not limited to the following examples.

<Example 1>
The apparatus shown in FIG. 1 was connected to an exhaust duct of a printing factory operating for 24 hours, and the exhaust gas from the printing factory was treated. The main malodorous component in the exhaust gas was toluene, and its concentration was almost constant at 200 ppm. For the microbial liquid, activated sludge collected from the kitchen wastewater treatment facility is stored in the microbial liquid tank of the same device as in FIG. 1, and air containing volatile organic compounds such as benzene, toluene, xylene, etc. is in gas-liquid contact. The solution was used for 3 weeks at a temperature (about 25 ° C.).

  The sludge collected from the kitchen abatement facility (standard activated sludge method) in the station building was used as the activated sludge. In addition, air containing 100 ppm of benzene, 100 ppm of toluene, and 100 pm of xylene was used as the gas supplied at the time of acclimatization.

  In the gas-liquid contact material in the gas-liquid contact portion, the height between the top of the protrusion on the corrugated plate and the bottom of the groove is 4.5 mm, and the length between the tops of adjacent protrusions A gas-liquid contact material formed from a corrugated plate having a thickness of 10 mm was used.

  In this example, nutrients were supplied to the microbial fluid. Toluene, which is a major component of malodorous gas, was used as a nutrient, and was manually supplied to the microorganism tank 1 several drops a day.

  In this embodiment, the gas-liquid contact time is 2 seconds, the temperature of the microbial liquid is about 25 ° C., the amount of malodorous gas supplied to the gas-liquid contact portion is 1 kg / min, and the amount of liquid retained is 5 [kg. ] (= [L]). Furthermore, the residence time was 5 days, 1 [kg] of the microbial solution was discharged every day, 1 [kg] of water was replenished, and water corresponding to the evaporation amount was appropriately replenished. The removal rate of toluene from the exhaust gas is shown in FIG.

  In addition, the removal rate of toluene from exhaust gas was calculated | required by the percentage of the concentration of toluene in the process air discharged | emitted from the gas-liquid contact part with respect to the concentration of toluene in the exhaust gas before being supplied to a gas-liquid contact part. . The concentration of toluene in the gas was measured with a detector tube manufactured by Gastec Corporation. Moreover, it measured also by Shimadzu Corporation gas chromatography GC-17, and performed the cross check.

  As shown in FIG. 6, when the residence time was 5 days, the removal rate of toluene was low in 2 to 3 days from the start of the exhaust gas treatment, but after that, the exhaust gas was exhausted at a high removal rate of 80% or more. The toluene in the gas could be removed. This is considered to be because bacteria that remove toluene from the exhaust gas have become dominant by setting the residence time of the microorganism liquid constant.

  The reason for the low toluene removal rate at the beginning of the treatment is that it takes 2-3 days for the microorganisms in the microorganism solution to acclimatize and begin to grow in a slightly different exhaust gas treatment environment than the environment in which the microorganisms were acclimatized. Probably because. Note that the period during which the removal rate is low at the beginning of treatment varies depending on the difference between the habituation environment of microorganisms and the treatment environment of exhaust gas, and may take about two weeks.

<Comparative Example 1>
Exhaust gas was treated in the same manner as in Example 1 except that the microbial fluid was not drained from the microbial fluid tank. The removal rate of toluene from the exhaust gas is shown in FIG. As shown in FIG. 6, in this comparative example, the removal rate of toluene in the exhaust gas is improved for several days after the treatment of the exhaust gas, that is, the flow of the microorganism liquid to the gas-liquid contact portion is started. Then it dropped sharply.

  In this comparative example, the number of living microorganisms in the microorganism solution was measured. The number of viable microorganisms was measured by a plate culture method using a standard agar medium. The change in the number of viable microorganisms in the microorganism solution in this comparative example is shown in FIG. According to FIG. 7, the number of viable microorganisms increased as the removal rate of toluene increased, and a certain number of viable bacteria was maintained thereafter. That is, at the time when the removal rate of toluene decreased, there was no decrease in the number of viable microorganisms corresponding to the decrease in the removal rate of toluene.

In this comparative example, the rate of change in oxygen utilization rate coefficient (K _r ) of the microbial fluid was measured. The oxygen utilization rate coefficient of the microbial fluid was measured according to the Japan Sewerage Association Sewerage Test Method (1997 version). The rate of change in the oxygen utilization rate coefficient of the microbial fluid is the ratio of the oxygen utilization rate coefficient of the microbial fluid over a predetermined number of days to the oxygen utilization rate coefficient of the initial microbial fluid. FIG. 8 shows changes in the rate of change in the oxygen utilization rate coefficient of the microbial fluid in this comparative example. According to FIG. 8, the ratio of the oxygen utilization rate coefficient of the microorganism liquid increased during the logarithmic growth phase of the microorganism, but decreased after the stationary phase although the number of microorganisms hardly changed. This indicates that the proportion of active microorganisms in the microbial fluid has decreased.

  According to the results of FIGS. 6 to 8, it is clear that the microorganisms in the microorganism liquid show excellent toluene removal ability in the logarithmic growth phase, but hardly decompose toluene in the stationary phase or the death phase. It was.

  Further, according to Example 1 and Comparative Example 1, the removal of toluene from the exhaust gas of microorganisms by replacing the microorganism liquid so that the growth state of the microorganisms in the microorganism liquid is always maintained in the logarithmic growth phase. It became clear that the ability could be kept above a certain ability. The reason why the toluene in the exhaust gas, which is originally a water-insoluble component that hardly dissolves in water, is taken in and decomposed, is the enzyme in which the microorganism acts as a surfactant during the logarithmic growth phase of the microorganism in the microorganism liquid. This is probably because microorganisms actively produced substances that promote the dissolution of water-insoluble components such as toluene in water, and this promoted the dissolution of toluene in the microbial solution.

<Comparative example 2>
Exhaust gas treatment was performed in the same manner as in Example 1 except that the discharge of the microbial solution and the supply of water and nutrients were controlled so that the residence time of the microbial solution was 1 day. For microbial fluid replacement, drain the microbial fluid continuously with a pump whose flow rate has been adjusted so that the residence time is one day, replenish the same amount of water, and replenish the amount of water as appropriate. I went there. The removal rate of toluene from the exhaust gas is shown in FIG.

  As shown in FIG. 6, in this comparative example, the removal rate of toluene was not improved. This is because the rate of decrease in the number of viable microorganisms due to the discharge of the microorganism liquid with the control of the residence time is larger than the growth rate of the microorganisms, so the microorganisms are discharged from the microorganism liquid tank, This is probably because the number of viable microorganisms in the liquid decreased. When the residence time is 1 day, the turbidity of the microbial solution on the 5th day from the start of the treatment is almost the same as that of fresh water, and most of the microorganisms seem to have flowed out of the removal device.

<Comparative Example 3>
Exhaust gas treatment was performed in the same manner as in Example 1 except that the discharge of the microbial solution and the supply of water and nutrients were controlled so that the residence time of the microbial solution was 20 days. The replacement of the microbial liquid is to continuously discharge the microbial liquid with a pump whose flow rate has been adjusted so that the residence time is 20 days, replenish the same amount of water, and replenish appropriately the amount of water for evaporation. I went there. The removal rate of toluene from the exhaust gas is shown in FIG.

  As shown in FIG. 6, in this comparative example, the toluene removal rate once improved, and after maintaining a high toluene removal rate for about 5 to 7 days, the toluene removal rate decreased. This is thought to be due to the longer residence time, the longer the time in the stationary phase or the death phase of the microorganism in the microbial solution in the logarithmic growth phase, the lower the ability to remove toluene as a whole, The trend is basically the same as in Comparative Example 1 where drainage was not performed.

<Example 2>
Exhaust gas treatment was performed in the same manner as in Example 1 except that the residence time and the microbial solution were changed. Then, in the treatment of the exhaust gas at each residence time, the number of days with a toluene removal rate of 70% or more was obtained. The replacement of the microbial liquid is performed by continuously discharging the microbial liquid with a pump whose flow rate is adjusted so that each residence time is reached, replenishing the same amount of water, and appropriately replenishing the amount of evaporation. It was.

In addition, the microorganism liquid (2) obtained by adapting the microorganism liquid (1) of Example 1 and the sludge collected from the kitchen wastewater treatment facility in the same manner as the activated sludge of Example 1 and the seed sludge are used as the microorganism liquid. The microbial liquid (3) that did not exist was used. The results are shown in Table 1.

  The microbial liquid (3) that does not use seed sludge circulates tap water instead of the microbial liquid in an experimental removal device having the same configuration as that shown in FIG. 1, and contains normal outdoor air and malodorous components. By contacting the malodorous gas and tap water for 30 days in the gas-liquid contact section, the bacteria in the air are taken into the tap water, and only the bacteria that adapt to the malodorous substance out of the taken bacteria grow. Microbial fluid produced. The microbial fluids (1), (2), and (3) are microbial fluids obtained by different methods, but are brown microbial fluids having almost the same appearance.

  Table 1 shows that the removal rate of toluene can be maintained high for a long time in the range of 2 to 14 days, although the optimum residence time varies depending on the type of the microbial solution used.

<Example 3>
The exhaust gas treatment was performed in the same manner as in Example 1 using the apparatus of FIG. 3 instead of the apparatus of FIG. The chromaticity of the microbial solution in the microbial solution tank was measured using a chromaticity meter manufactured by HACH, 2100AN Laboratory Turbidimeter. FIG. 9 shows the relationship between the chromaticity of the microbial fluid in the microbial fluid tank and the toluene removal rate.

  As shown in FIG. 9, when the microbial solution was replaced so that the residence time was 5 days, the chromaticity of the microbial solution was in the range of 50 to 100 degrees and the removal rate of toluene was 80 % Or more. From the above, it has been clarified that toluene can be removed from exhaust gas with high efficiency by replacing the microbial liquid so that the chromaticity of the microbial liquid in the microbial liquid tank is less than 100 degrees.

<Comparative example 4>
Exhaust gas was treated in the same manner as in Example 3 except that the microbial fluid was not discharged. Further, the exhaust gas was treated in the same manner as in Example 3 except that the microbial solution was replaced so that the residence time was 20 days. FIG. 9 shows the relationship between the chromaticity of the microbial liquid in the microbial liquid tank and the toluene removal rate in this comparative example.

  As is apparent from FIG. 9, when the chromaticity of the microbial liquid in the microbial liquid tank exceeds 100 degrees, the removal rate of toluene decreases. In the period until the microorganisms in the microbial fluid are adapted to the exhaust gas treatment conditions, both the chromaticity of the microbial fluid and the removal rate of toluene are low. The removal rate is not displayed in FIG.

From Example 3 and Comparative Example 4, it was confirmed that the chromaticity of the microbial fluid and the ability to remove toluene correlate. Therefore, by measuring the chromaticity and turbidity of the microbial fluid using transmitted light or reflected light, and replacing the microbial fluid so that the measured value is below a certain value, the growth state of the microorganisms in the microbial fluid Was maintained in the state of logarithmic growth phase, and it became clear that the removal ability of volatile organic compounds could be kept higher than a certain level.

  The threshold value of the chromaticity of the microbial liquid at which the removal rate of volatile organic compounds is reduced varies depending on conditions such as the type of microorganism, the type of substance to be removed, and the composition of the gas to be treated. The threshold value can be determined in advance by measuring the relationship between the removal rate of malodorous components and the chromaticity of the microbial fluid by trial operation. When the threshold value was confirmed with several kinds of microorganism liquids, the threshold value was in the range of 10 to 500 degrees.

<Example 4>
The exhaust gas ventilation rate Q is 1 kg / min, and the amount of microbial fluid in the microbial fluid tank (retained fluid amount) is 0.5L (ie 0.5Q), 1L (ie 1Q), and 5L (ie 5Q). Exhaust gas treatment was performed in the same manner as in Example 1 except that. The transition of the removal rate of toluene in each retained liquid amount is shown in FIG.

  As shown in FIG. 10, when the amount of the retained liquid was small, the toluene removal rate decreased. This is presumably because the total amount of toluene dissolved in the microbial fluid from the inflowing exhaust gas is reduced, and the removal rate of toluene in the exhaust gas is reduced. When the amount of liquid retained was large, there was no inconvenience regarding the removal rate of toluene. However, when the amount of the microbial solution is too large compared to the supply amount of the exhaust gas, the nutrients of the microorganisms in the microbial solution are likely to be insufficient, so that it is necessary to supply more nutrients to the microbial solution. If the amount of liquid retained is large, a large microbial liquid tank is required. Therefore, considering the running cost and the initial cost, the maximum amount of the retained liquid is about 50Q.

<Example 5>
Exhaust gas treatment was performed in the same manner as in Example 1 except that the apparatus of FIG. 1 was connected to the exhaust duct of a printing factory that was not operated for 24 hours. This printing factory operates from 8:00 to 17:00 from Monday to Saturday. The main component of the malodorous component contained in the exhaust gas is toluene. Table 2 shows changes in the removal rate of toluene in this removal apparatus.

  In this example, the removal rate of toluene was obtained by collecting a microbial solution from the microbial solution tank of the removal device of this example at the collection date and time shown in Table 2, and using a small evaluation removal device having the same configuration as in FIG. Used, the air containing 200 ppm of toluene was supplied to the evaluation removal apparatus as a bad odor gas, and the evaluation removal apparatus was operated under the same conditions as the removal apparatus of this example using the collected microbial liquid. .

As is clear from Table 2, no decrease in the toluene removal rate was observed even at 8 o'clock on Monday, the most severe condition. Thus, even if the supply of toluene from the exhaust gas is stopped for 39 hours, no reduction in the removal rate of toluene is observed, and the odor component from the odor gas is not affected regardless of the length of time during which the odor component supply is stopped. Stable removal was possible.

It is a figure which shows roughly the structure of one Embodiment of the removal apparatus of the malodorous component of this invention. It is a figure which shows an example of the gas-liquid contact material 2b in FIG. It is a figure which shows schematically the structure of other embodiment of the removal apparatus of the malodorous component of this invention. It is a figure which shows schematically the structure of other embodiment of the removal apparatus of the malodorous component of this invention. It is a figure which shows schematically the structure of other embodiment of the removal apparatus of the malodorous component of this invention. It is a figure which shows an example of transition of the removal rate of toluene from malodorous gas by residence time. It is a figure which shows an example of transition of the viable count of the microorganisms in the microbial liquid at the time of not discharging | emitting a microbial liquid. It is a figure which shows an example of transition of the ratio of the change of the oxygen utilization rate coefficient of the microbial liquid at the time of not discharging | emitting microbial liquid. It is a figure which shows an example of the relationship between the chromaticity of the microbial liquid in a microbial liquid tank, and the removal rate of toluene from malodorous gas. It is a figure which shows an example of transition of the removal rate of toluene when the amount of microorganisms liquid with respect to the supply amount of malodorous gas is changed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microbial liquid tank 2 Gas-liquid contact part 2a Casing 2b Gas-liquid contact material 3 Water supply flow path 4, 6, 8, 12 Pump 5 Microbial liquid discharge flow path 7 Microbial liquid supply flow path 9 Injection nozzle 10, 31 Odor gas supply Flow path 11 Microbial liquid recirculation flow path 13, 32 Process air discharge flow path 14, 33 Blower 15a Corrugated sheet group 15b, 15c Side corrugated sheet group 21, 22 Valve 23 Colorimeter 24 Control device 30 Gas dispersion member

Claims (13)

A method for removing malodorous components from malodorous gas by bringing the malodorous gas containing the malodorous component and gas, and the microorganism liquid containing the microorganism that decomposes the malodorous component and the aqueous medium into gas-liquid contact at the gas-liquid contact portion. Because
The malodorous component is a water-insoluble malodorous component or a volatile organic compound,
Controlling the viable count of microorganisms in the microbial fluid so that the microorganisms grow logarithmically in the microbial fluid ,
The microorganism solution was supplied to the gas-liquid contact portion, wherein the isosamples is circulated by liquid contact in the said malodorous gas microbial solution and the gas-liquid contact portion. The method of claim 1, wherein the to contact each other is circulated in the opposite direction liquid and said microorganisms liquid and the malodorous gas in the gas-liquid contact portion. The method according to claim 1 or 2, characterized in that circulating the microbial liquid to the gas-liquid contact portion. The supply amount of the malodorous gas supplied to the gas-liquid contact portion when the q kg / min, claim 3, characterized in that circulating the microbial solution Q~50Qkg to the gas-liquid contact portion The method described. The microbial liquid is partially replaced with the aqueous medium so that the same amount of the aqueous medium as the amount of the microbial liquid in the circulating system of the microbial liquid is supplied in 2 to 14 days. the method according to any one of claims 1-4, characterized by controlling the number. Measuring the number of living microorganisms in the microorganism solution, and controlling the number of living microorganisms in the microorganism solution by diluting the microorganism solution with an aqueous medium when the number of living microorganisms exceeds a predetermined value. the method according to any one of claims 1-4, characterized. Claim 6, wherein the chromaticity of the microorganism was determined, the chromaticity is characterized in that the microorganism is diluted with an aqueous medium to control the viable count of microorganisms microbial solution when 10 to 500 degrees The method described in 1. The malodorous component is a volatile organic compound that is one or more selected from the group consisting of toluene, xylene, and benzene, and the microorganism is volatile by passing a gas containing the volatile organic compound through the activated sludge. The method according to any one of claims 1 to 7 , which is a microorganism in activated sludge adapted to an organic compound. A microbial liquid tank that contains a microbial liquid containing a microorganism that decomposes malodorous components and an aqueous medium, and a gas for liquid-liquid contact between the malodorous gas containing the malodorous ingredient and gas and the microbial liquid in the microbial liquid tank. A liquid contact unit, an aqueous medium supply device for supplying an aqueous medium to the microbial liquid tank, and a microbial liquid discharge device for discharging the microbial liquid from the microbial liquid tank, wherein the malodorous component is water-insoluble. It is a malodorous component or volatile organic compound, and the viable count of microorganisms in the microbial fluid is controlled so that the viable count of microorganisms in the microbial fluid is maintained within the range of the viable count in the logarithmic growth phase of the microorganism. A device for removing malodorous components from malodorous gas. The gas-liquid contact portion supplies the microbial liquid in the microbial liquid tank to the casing, the gas-liquid contact material that is accommodated in the casing and forms a passage divided in the casing, and the gas-liquid contact material in the casing. The microbial liquid supply device is a member to which malodorous gas is supplied from the lower part of the gas-liquid contact material in the casing, and the microbial liquid that has contacted the malodorous gas at the gas-liquid contact portion is returned to the microbial liquid tank. The apparatus of claim 9 . The apparatus further includes a water supply / drainage time control device for supplying a predetermined amount of the aqueous medium to the microbial liquid tank by the aqueous medium supply device at a predetermined interval or speed and discharging the predetermined amount of the microbial liquid from the microbial liquid tank by the microbial liquid discharge device. The apparatus according to claim 9 or 10 , characterized in that According to the optical property measuring device for measuring the optical properties of the microbial fluid in the microbial fluid tank and the optical properties of the microbial fluid measured by the optical property measuring device, the aqueous media supply device supplies the aqueous media to the microbial fluid tank, The apparatus according to claim 9 or 10 , further comprising an optical characteristic control device for discharging the microbial liquid from the microbial liquid tank by the microbial liquid discharging apparatus. The optical property measuring device is a device for measuring the chromaticity of the microbial fluid in the microbial fluid tank, and the optical property controlling device supplies the aqueous medium when the measured value of the chromaticity of the microbial fluid reaches a predetermined value. The apparatus according to claim 12 , wherein the aqueous medium is supplied to the microbial liquid tank by the apparatus, and the microbial liquid is discharged from the microbial liquid tank by the microbial liquid discharge device.

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