JP2007260559A - Biological deodorizer and biological deodorization method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve an efficiency in deodorization treatment of an odorant gas containing a sulfur series odorant with a microorganism to improve the miniaturization and treating performance of a biological deodorizer. <P>SOLUTION: An upstream packed bed 21 and a downstream packed bed 31 are formed by each filling deodorization treating chambers 20, 30 of the biological deodorizer 1 with a porous ceramic-made carrier where the microorganism that decomposes the sulfur series odorant is immobilized, after an easily decomposable sulfur series odorant is mainly decomposed by allowing the odorant gas to pass through the bed 21 and a hardly decomposable sulfur series odorant is mainly decomposed by allowing the remaining gas to pass through the bed 31. The size of the carrier in the bed 31 is made smaller that of the carrier in the bed 21 and a carrier surface area and a total carrier surface area per unit volume in the bed 31 are made bigger than those of both the areas in the bed 21. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a biological deodorization apparatus and a biological deodorization method for decomposing and deodorizing odorous substances contained in odorous gas using microorganisms, and in particular, efficiently deodorizing odorous gas containing sulfur-based odorous substances as odorous substances. The present invention relates to a biological deodorization apparatus and a biological deodorization method.

  Gases generated at sewage treatment plants, livestock facilities, various wastewater treatment facilities, etc. contain a large amount of sulfur-based odorous substances mainly composed of hydrogen sulfide, methyl sulfide, methyl disulfide, and methyl mercaptan as odorous substances. In general, hydrogen sulfide is contained at a relatively high concentration, although it varies depending on the equipment and the season of generation. The odorous gas containing these odorous substances is released into the atmosphere after removing the odorous substances and deodorizing from the viewpoints of maintaining the living environment of surrounding residents, environmental conservation, and ensuring safety in the facility.

  As a deodorizing method for this odor gas, a method for physically and chemically removing odorous substances such as an activated carbon adsorption method and a chemical cleaning method has been widely used in the past. At the same time, biological deodorization methods with low running costs have attracted attention, and are becoming widespread mainly in sewage treatment plants. This biological deodorization method uses a function of precipitating and oxidatively degrading odorous substances of aerobic microorganisms (here, sulfur-based odorous substance oxidizing bacteria), and a carrier on which such microorganisms are immobilized is used. Odor gas is supplied to the packed packed bed, and each sulfur-based odorous substance is oxidized and decomposed into sulfuric acid by microorganisms that live on the carrier to perform deodorization.

  Here, there is a difference in the ease (degradability) that sulfur-based odorous substances are decomposed by microorganisms. Compared to easily decomposable hydrogen sulfide that is decomposed relatively easily, methyl sulfide, methyl disulfide, methyl Mercaptans have a slow degradation rate and are hardly decomposable. This is because hydrogen sulfide is directly decomposed into sulfuric acid, while other sulfur-based odorous substances are once converted into intermediate products and then into sulfuric acid. That is, methyl sulfide and methyl disulfide are converted into methyl. This is because it is once converted into mercaptan and then further converted into hydrogen sulfide together with methyl mercaptan which is originally present, and then decomposed into sulfuric acid. In addition, microorganisms that oxidatively decompose sulfur-based odorous substances prefer different habitat environments for each species. For example, hydrogen sulfide-oxidizing bacteria that decompose hydrogen sulfide can maintain activity even at pH 2 to 4, but other sulfur-based microorganisms described above. Odor-oxidizing bacteria are activated in a neutral range (about pH 6 to 8), and cannot function sufficiently at pH 5 or lower.

  Therefore, when the odor gas is supplied to the packed bed of the carrier, the decomposition of the odorous substance mainly proceeds with a large amount of easily decomposable hydrogen sulfide, and accordingly, sulfuric acid is generated and the pH of the packed bed gradually increases. descend. As a result, hydrogen sulfide oxidizing bacteria are activated and proliferated, while other sulfur odorant oxidizing bacteria become difficult to live, and the degradation performance of methyl sulfide, methyl disulfide, and methyl mercaptan gradually decreases. Therefore, conventionally, the habitats of hydrogen sulfide oxidizing bacteria and other oxidizing bacteria are separated, grown in an environment suitable for each, and the odorous gas is sequentially supplied to reduce degradation of odorous substances (deodorizing performance). A biological deodorization device that suppresses is proposed (see Patent Document 1).

FIG. 3 is a side sectional view showing a schematic configuration of this conventional biological deodorizing apparatus 100.
As shown in the figure, the biological deodorization apparatus 100 includes a biological deodorization tower 110 having an odor gas inlet 111 and an outlet 112, the interior of which is partitioned by a partition wall 113, and upstream and downstream of the gas flow path. These deodorizing chambers 120 and 130 are formed, and a plurality of granular carriers 121A and 131A are filled in each of them to form packed layers 121 and 131. A gas passage 114 that allows the deodorizing chambers 120 and 130 to communicate with each other is formed at the upper end portion of the partition wall 113, and the odor gas supplied from the inflow port 111 moves up the upstream deodorizing chamber 120 to the upstream side. The deodorized gas passes through the packed bed 121, enters the downstream deodorizing treatment chamber 130 through the gas passage 114, descends, passes through the downstream packed bed 131, is further deodorized, and is discharged from the outlet 112.

  In addition, sprinkling means 122 and 132 for spraying the filling layers 121 and 131 are provided at the upper portions of the deodorizing treatment chambers 120 and 130, respectively, and water is sprinkled on the bottom portions to pass through the filling layers 121 and 131. Water storage tanks 123 and 133 for storing water are formed, and pumps 124 and 134 provided between them are driven to circulate and use the water. The water tanks 123 and 133 are connected to water supply pipes 125 and 135 for replenishing water and overflow pipes 126 and 136, respectively, and the water surface position is kept constant and attached to the water supply pipes 125 and 135. The pH of the water storage tanks 123 and 133 is adjusted and maintained within a predetermined range by the pH adjusters injected from the pH adjuster injection pipes 127 and 137.

  The deodorization of the odor gas is performed by absorbing odor substances in the gas by moisture on the surfaces of the carriers 121A and 131A, and taking in them by oxidizing bacteria immobilized on the carriers 121A and 131A. Accordingly, the water spray to each of the packed layers 121 and 131 has a role of preventing the surfaces of the carriers 121A and 131A from being dried and reliably maintaining a state in which a water film or the like is formed. At the same time, the watering is performed by washing the carriers 121A and 131A, removing sulfuric acid generated by deodorization to adjust the pH of the packed layers 121 and 131, and supplying water necessary for the inhabiting of microorganisms on the carriers 121A and 131A. Also serves.

  In this conventional biological deodorization apparatus 100, hydrogen sulfide-oxidizing bacteria are mainly immobilized on the carrier 121A of the upstream packed bed 121, and the water in the upstream water storage tank 123 is adjusted to a pH suitable for its habitat. The upstream packed bed 121 is maintained in a habitat suitable for hydrogen sulfide oxidizing bacteria. Moreover, while oxidizing the oxidizing bacteria of other sulfur-based odorous substances to the carrier 131A of the downstream packed bed 131, the water in the downstream water storage tank 133 is adjusted to a pH suitable for their habitat, and the adjusted water is used. Water is sprayed to maintain the downstream packed bed 131 in a habitat suitable for other oxidizing bacteria.

  In this way, the habitat of each oxidizing bacterium is separated and grown in a suitable environment, and the relatively high concentration and easily decomposable hydrogen sulfide in the supplied odor gas is decomposed and removed in the upstream packed bed 121. Other sulfur-based odorous substances (methyl sulfide, methyl disulfide, methyl mercaptan) that are difficult to decompose are decomposed and removed by the downstream packed bed 131. As described above, in this conventional apparatus 100, each oxidizing bacterium is separated and grown while maintaining the activity in each packed bed 121, 131, and the degradation of the odorous substance decomposition treatment performance is suppressed.

  Here, there is a certain limit to the ability of the microorganisms to decompose, and in order to efficiently decompose odorous substances, especially persistent sulfurous odorous substances, the contact area between the odorous gas and the carriers 121A and 131A is increased. It is necessary to cause more microorganisms to decompose by increasing the contact time. However, in the conventional apparatus 100, the form of the carriers 121A and 131A and the filling mode such as the packing density are not particularly considered from the above viewpoint, and therefore the contact area and time are insufficient. As a result, the efficiency of the decomposition treatment of odorous substances may be lowered.

  Such a problem can be dealt with by increasing the volume of the packed beds 121 and 131 and filling the carriers 121A and 131A more, but in this case, the apparatus 100 is enlarged and a large installation space is required. This causes a problem that the equipment cost increases. Moreover, even if the particle size of the carriers 121A and 131A is reduced without increasing the volume of the packed layers 121 and 131 and the specific surface area is increased, the contact area with the odor gas is increased, which is effective in improving the processing efficiency. is there. However, in this case, since the gaps between the carriers through which the odor gas passes are also narrowed, foreign substances are likely to be clogged therewith, and the filling layers 121 and 131 may be blocked to prevent smooth passage of the odor gas. There is.

  That is, for example, in odorous gas generated at a sewage treatment plant, hydrogen sulfide generally occupies about 80 to 90% of the odorous substance. However, such odorous gas having a high concentration of hydrogen sulfide is treated. In such a case, elemental sulfur, which is an intermediate product of the decomposition reaction of the sulfur-based odorous substance, may be deposited, and the deposited sulfur may accumulate and the interval between the carriers may be narrowed or blocked. At the same time, hydrogen sulfide oxidizing bacteria using hydrogen sulfide as an energy source may rapidly grow upstream of the odor gas and form sludge-like nodules with the above-mentioned precipitated sulfur, which may clog the gaps between the carriers. There is also. In such a case, the packed layers 121 and 131 are blocked, and it becomes difficult for the odorous gas to flow, and the contact between the microorganisms and the odorous substance is hindered, resulting in a problem that the efficiency and performance of the decomposition process are lowered. This precipitation of sulfur and formation of nodules are particularly likely to occur in the upstream packed bed 121 that decomposes and removes hydrogen sulfide, and may also occur when the hydrogen sulfide concentration temporarily increases due to seasonal fluctuations or the like. .

  In addition, it is difficult to stably deodorize odorous gas with varying odorous substance content using only a biological deodorizing device, and when the device is enlarged to reliably deodorize such odorous gas. Increases the equipment cost. Therefore, in such a biological deodorization apparatus, an activated carbon adsorption tower is connected to the gas outlet and adsorption removal of low-concentration odorous substances remaining in the gas is widely performed. In addition, activated carbon has a tendency to shorten its life when moisture adheres to the surface, such as the ability to adsorb odorous substances, so when an activated carbon adsorption tower is installed, the mist in the gas is placed in front of the gas inlet. It is common to provide a mist separator for removing gas and a deodorizing fan (blower) for sending gas to the activated carbon adsorption tower.

  Therefore, in this case, the number of devices constituting the deodorizing system is increased, and the entire apparatus including them is increased in size to increase the installation space, resulting in an increase in equipment cost. In addition, there is a problem that the running cost increases, such as the energy consumption of the entire apparatus, the number of maintenance inspections, and the time and effort, and the need for regular replacement of consumables such as activated carbon.

JP-A-8-323136

  The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to improve the efficiency of deodorizing treatment by microorganisms of odorous gas containing sulfur-based odorous substances, and to reduce the size and processing performance of a biological deodorizing apparatus. It is to improve the facility cost and running cost.

According to the first aspect of the present invention, there is provided a gas flow path through which an odor gas containing a sulfur-based odor substance is circulated, and a microorganism that is disposed upstream of the gas flow path and mainly decomposes the easily decomposable sulfur-based odor substance. An upstream side packed bed filled with an immobilized carrier and a downstream side packed with a carrier that is arranged downstream of the gas flow path and mainly immobilized with microorganisms that decompose the hardly decomposable sulfur-based odorous substances. A biological deodorization apparatus for performing deodorization by sequentially passing the odorous gas through the upstream packed bed and the downstream packed bed, the total surface area of the carrier packed in the upstream packed bed being the upstream E1 <E2, where E1 is a value obtained by dividing the volume of the side packed bed by E1, and E2 is a value obtained by dividing the total surface area of the carrier packed in the downstream packed bed by the volume of the downstream packed bed. And
According to a second aspect of the present invention, in the biological deodorization apparatus according to the first aspect, the total surface area of the carrier packed in the downstream packed bed is larger than the total surface area of the carrier packed in the upstream packed bed. Features.
The invention according to claim 3 is the biological deodorization apparatus according to claim 1 or 2, wherein the carrier of the upstream packed bed and the downstream packed bed is formed in a granular form, and the carrier of the downstream packed bed is the upstream It is characterized by being formed smaller than the carrier of the side packed layer.
According to a fourth aspect of the present invention, in the biological deodorization apparatus according to any one of the first to third aspects, the carrier of the upstream side packed bed and the downstream side packed bed is made of a porous ceramic.
The invention according to claim 5 is the biological deodorization device according to any one of claims 1 to 4, wherein the upstream pH adjusting means for sprinkling water to the upstream packed bed and adjusting the pH of the upstream packed bed; A downstream pH adjusting means for sprinkling water on the downstream packed bed and adjusting the pH of the downstream packed bed, and independently controlling the pH of the upstream packed bed and the downstream packed bed. To do.
According to the sixth aspect of the present invention, an odor gas containing a sulfur-based odor substance is sequentially passed through an upstream packed bed and a downstream packed bed filled with a carrier on which microorganisms are immobilized, and the microorganisms immobilized on the carrier A biological deodorization method for decomposing and deodorizing a sulfur-based odor substance, the step of passing the odor gas through the upstream packed bed and decomposing mainly the easily decomposable sulfur-based odor substance, and the downstream side A step of allowing the odorous gas to pass through the packed bed and mainly decomposing the hard-to-decompose sulfur-based odorous substance, and determining the total surface area of the carrier packed in the upstream packed bed by the volume of the upstream packed bed E1 <E2 where E1 is a value obtained by dividing E1 and a value obtained by dividing the total surface area of the carrier packed in the downstream packed bed by the volume of the downstream packed bed is E2.
According to a seventh aspect of the present invention, in the biological deodorization method according to the sixth aspect, the total surface area of the carrier packed in the downstream packed bed is made larger than the total surface area of the carrier packed in the upstream packed bed. Features.
The invention of claim 8 is the biological deodorization method according to claim 6 or 7, wherein water is sprayed on the upstream packed bed, and the pH of the upstream packed bed is adjusted to 0.5 or more and 5 or less, Sprinkling water into the downstream packed bed, and adjusting the pH of the downstream packed bed to 6 or more and 8 or less.

  According to the present invention, it is possible to improve the efficiency of deodorizing treatment by microorganisms of odorous gas containing sulfur-based odorous substances, reducing the size of the biological deodorizing device and improving the processing performance, and reducing the equipment cost and running cost. can do.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side sectional view showing a schematic configuration of the biological deodorization apparatus of this embodiment, and FIG. 2 is a view taken along the line FF in FIG.
Similar to the conventional biological deodorization apparatus 100 shown in FIG. 3, the biological deodorization apparatus 1 includes a sulfur-based odor substance mainly composed of hydrogen sulfide, methyl sulfide, methyl disulfide, and methyl mercaptan generated in a sewage treatment plant or the like. It is an apparatus for deodorizing odor gas using the above-mentioned carrier on which various microorganisms are immobilized, and deodorizes by oxidizing and decomposing sulfur-based odorous substances in the odor gas into sulfuric acid by microorganisms.

  As shown in FIGS. 1 and 2, the biological deodorization apparatus 1 includes a substantially box-shaped biological deodorization tower 10 having an odor gas inlet 11 and an outlet 12, and the interior thereof is upstream of a gas flow path by a partition wall 13. It is divided into two deodorizing treatment chambers 20 and 30 on the side (inlet 11 side) and downstream (outlet 12 side). Each of the deodorization treatment chambers 20 and 30 has a rectangular tube shape with a substantially rectangular cross section (see FIG. 2), is filled with a plurality of carriers immobilizing microorganisms in each of the substantially central portions in the vertical direction, and is upstream of substantially the same volume. And the downstream side filling layers 21 and 31 are formed. A gas passage 14 is formed at the upper end of the partition wall 13 to connect the deodorizing chambers 20 and 30 to each other. The odor gas supplied from the inflow port 11 passes along the gas flow path in the biological deodorization tower 10. First, after the upstream deodorization treatment chamber 20 is lifted and passed through the upstream packed bed 21 to be deodorized, it passes through the gas passage 14 and enters the downstream deodorizing treatment chamber 30, and descends to the downstream packed bed 31. Is further deodorized and discharged from the outlet 12.

  In addition, a sprinkler 40 for sprinkling the packed beds 21, 31 is provided on the top of the biological deodorizer 1. The watering device 40 includes a pump (not shown) for sending water to be sprinkled from a water storage tank, a water flow rate adjusting means 41 including a flow meter 41A and a valve 41B for adjusting the flow rate of water from the pump, Water pipe 42 that branches and guides water to the upper side of each packed bed 21, 31, an electric valve 43 provided in each branched path of the spray pipe 42, and above each packed bed 21, 31, respectively. And a plurality of watering nozzles 44 disposed therein.

  This watering device 40 operates each motor-operated valve 43 independently while adjusting the flow rate of water by the water flow rate adjusting means 41, and opens and closes each at a predetermined timing to intermittently pass from the watering nozzle 44 to each packed bed 21, 31. Water is sprayed and the generated sulfuric acid is removed and water is replenished to microorganisms. In addition, by controlling the watering time, watering cycle, watering amount, etc. to each packed bed 21, 31 independently of each other to adjust the removal amount of sulfuric acid from each packed bed 21, 31, etc. It is designed to adjust independently. Accordingly, each of the water tanks 22 and 32 (to be described later) that receives each water spray is provided with pH measuring means (not shown), and water is sprayed based on the measured value or empirical rule. Here, the pH of the upstream packed bed 21 is adjusted to be 0.5 or more and 5 or less, and the pH of the downstream packed bed 31 is adjusted to be 6 or more and 8 or less.

  On the other hand, at the bottom of the biological deodorization tower 10 (each deodorization treatment chamber 20, 30), water storage tanks 22, 32 for storing the sprinkled water are provided, and these are formed at the lower end of the partition wall 13. The communication holes 15 communicate with each other through the water passage holes 15. Further, an overflow pipe 16 is connected to a side surface of the biological deodorization tower 10 (a side surface on the front side of the deodorization treatment chamber 20 in FIG. 1) at a position lower than the inlet port 11 and the outlet port 12 of the odor gas. The water surface position of the tanks 22 and 32 is maintained at a fixed position that does not prevent the odor gas from entering and exiting, and a drain 17 used for draining is connected to the lower end portion. The water storage tanks 22 and 32 maintain the humidity in the biological deodorization tower 10 to a certain level, prevent the carrier of the packed layers 21 and 31 from drying, and treat the oxidative decomposition (deodorization) of odorous substances by microorganisms. It has a role to prevent the deterioration of

Further, the biological deodorization apparatus 1 has a value obtained by dividing the total surface area of the carrier packed in the upstream packing layer 21 by the volume of the upstream packing layer 21 as E1, and the total surface area of the carrier packed in the downstream packing layer 31 downstream. When the value divided by the volume of the side filling layer 31 is E2, E1 <E2. That is, the surface area of the carrier per unit volume of the downstream side packed layer 31 (the density of the surface area of the carrier: m ² / m ³ ) is made larger than that of the upstream side packed bed 21, thereby increasing the contact area of the downstream side packed bed 31 with the odor gas.

  In the present embodiment, the carrier of both the packed layers 21 and 31 is formed of a substantially cylindrical porous ceramic in which a large number of communication holes are formed, and the carrier of the upstream packed layer 21 is satisfied in order to satisfy the above-described relationship. Are formed into large particles (for example, 10 mm in diameter and 25 mm in length), and the carrier of the downstream packing layer 31 is formed into small particles (for example, 6 mm in diameter and 10 mm in length). These large carriers and small carriers vary in size, but are statistically significant in the average value of the volume of each large carrier and the average value of the volume of each small carrier. If there is a difference (the difference in the average value of the particle diameters is larger than the dispersion of the volume variation between the large carrier and the small carrier), the desired effect can be obtained.

  Therefore, in the present embodiment, the supports of the upstream packed bed 21 and the downstream packed bed 31 are the number of carriers per unit volume of each packed bed 21, 31 in the downstream packed bed 31 rather than the upstream packed bed 21. Although it increases, the sum of the volume of each carrier contained per unit volume of each of the packed layers 21 and 31 becomes substantially equal. Here, “increased” means a carrier contained in a unit volume of each packed layer 21, 31 rather than a dispersion when an arbitrary portion is taken from each packed layer 21, 31 and the number is counted. The case where the difference of the average value of the sum total of every one volume is large is said and "it becomes substantially equal" means taking the arbitrary part from each filling layer 21,31, and unit volume of the filling layers 21,31. The difference in the average value of the total volume of each carrier contained per unit volume of the respective packed layers 21 and 31 is smaller than the dispersion of the total value of the volume of each carrier contained around the carrier. To tell.

  In addition, the carriers of the packed layers 21 and 31 have other properties other than the dimensions, for example, the shape of the communicating holes and the porosity, etc., and the density of the carrier surface area is determined by the downstream packed layer 31 on the upstream side. It becomes higher than the filling layer 21. At the same time, in the present embodiment, the packed layers 21 and 31 are formed in substantially the same volume, so that the total surface area of the carrier filled in the downstream packed layer 31 is larger than the total surface area of the carrier filled in the upstream packed layer 21. Is also getting bigger. As described above, each of the packed layers 21 and 31 has been described in detail by taking a substantially columnar carrier as an example. However, the packed layers 21 and 31 are in a ribbon shape, a cylindrical shape, a brush shape, a spherical shape, and other shapes, In all carriers in which the same relationship as described above with respect to volume and surface area is established, the same actions and effects as in this embodiment can be obtained.

In addition, the large number of communication holes of each carrier in the present embodiment increases the surface area in contact with the odor gas, and has such a shape and density as to obtain sufficient water retention, product washability, durability, strength, etc. (For example, the diameter is about 1 mm, the porosity is 77%, the instantaneous water absorption is 150%, etc.). Here, each support is formed of an oxide ceramic (for example, SiO ₂ is 88%, Al ₂ O ₃ is 8%) made of silica, alumina, and the like. You may form with other ceramics with high intensity | strength, such as a product ceramic.

  The carrier of the upstream side packed bed 21 is mainly an oxidizing bacterium that oxidizes and decomposes a sulfur odor substance (hydrogen sulfide) that has a relatively high content and is easily decomposable. Oxidizing bacteria that oxidatively decompose other sulfur-based odorous substances (methyl sulfide, methyl disulfide, methyl mercaptan) that have low chemical content and are difficult to decompose are mainly immobilized and supported.

  The microorganisms are immobilized by the seeding operation of the microorganisms prior to the start of the operation of the apparatus 1 and the acclimatization operation. This immobilization is performed by filling each packed bed 21, 31 after each microorganism is attached to each carrier in advance. In addition, by the acclimatization operation, each microorganism is divided into a suitable environment to form a microflora, that is, an upstream packed bed having a pH of 0.5 or more and 5 or less. Alternatively, hydrogen sulfide oxidizing bacteria may be grown at 21 and other oxidizing bacteria may be grown at the downstream packed bed 31 having a pH of 6 or more and 8 or less.

Next, the deodorizing process of the odor gas containing the sulfur odor substance by the biological deodorizing apparatus 1 will be described.
First, odorous gas is supplied from the inlet 11 to the upstream deodorization treatment chamber 20, and the inside thereof is raised and passed through the upstream packed bed 21, and mainly easily degradable hydrogen sulfide by microorganisms immobilized on the carrier. Disassemble. Subsequently, the odor gas from which most of the hydrogen sulfide has been removed is moved to the downstream side deodorization treatment chamber 30 through the gas passage 14, and the inside thereof is lowered to pass through the downstream side packed bed 31 and immobilized on the carrier. The microorganisms mainly decompose other sulfur-based odorous substances that are hardly decomposable and, in some cases, undecomposed residual hydrogen sulfide. Thereafter, the deodorized gas is removed from the outflow port 12 to the atmosphere or the like by removing the odorous substance.

  When the flow of the odor gas along the gas flow path of the biological deodorization tower 10 is continuously performed, the pH of the packed beds 21 and 31 gradually decreases as sulfuric acid is generated by the decomposition of the odor substances. . Therefore, water is sprinkled onto each of the packed beds 21 and 31 by the watering device 40 at a predetermined timing to remove sulfuric acid. However, as described above, the pH of each of the packed beds 21 and 31 is independently adjusted by adjusting the watering time or the like. To adjust the pH of the upstream packed bed 21 to 5 or less and 0.5 or more suitable for the habitat of hydrogen sulfide oxidizing bacteria, and to adjust the pH of the downstream packed bed 31 to other persistent sulfur system Maintain 6 or more and 8 or less, which is suitable for the odorous bacteria.

  As described above, in the biological deodorization apparatus 1 of the present embodiment, each microorganism is inhabited while maintaining activity in an environment suitable for each, and the decomposition treatment efficiency and performance of each odorous substance in each packed bed 21 and 31 are improved. Let In addition, methyl sulfide, methyl disulfide, and methyl mercaptan are treated in the same downstream packed bed 31 so that microorganisms (microflora) are formed at the same location for each microorganism that decomposes them, and intermediate between the microorganisms in the flora. Improve the efficiency of the decomposition process by delivering the product. At the same time, after removing hydrogen sulfide having a high content in the upstream packed bed 21, the odor gas is passed through the downstream packed bed 31, thereby suppressing the amount of sulfuric acid produced in the downstream packed bed 31 and its pH. Is prevented from excessively decreasing and fluctuating. Thereby, control of pH of the downstream side packed bed 31 is facilitated, the activity of the microorganisms is prevented from being reduced, and the reduction in processing efficiency is suppressed.

  Further, the carrier surface area (contact area with odor gas) per unit volume of the downstream side packed bed 31 is increased to increase the decomposition performance (decomposition amount) of the odor substance per unit volume, and the hardly decomposable sulfur-based odor. Improve material processing efficiency. At the same time, the total surface area of the carrier of the downstream side packed bed 31 is made larger than that of the upstream side packed bed 21, and the hardly decomposable sulfur-based odor substance is brought into contact with more microorganisms to improve the performance of the decomposition process. Make sure to deodorize odor gas.

  Here, as described above, when the carrier particle size is reduced and the interval between the carriers is narrowed, the precipitated sulfur, the grown microorganisms, etc. form a nodule and the gap between the carriers is blocked to form a packed bed. May cause obstruction. However, the hardly decomposable sulfur-based odor substance that decomposes in the downstream side packed bed 31 has a relatively low concentration in the odor gas. For example, in a generated gas at a general sewage treatment plant, 10 to 20 of the total odor substance. Therefore, rapid growth of microorganisms that prey on them and precipitation of sulfur are unlikely to occur. Therefore, even if the downstream carrier layer 31 is filled with a small carrier as in this embodiment, the retention of odor gas and the deodorization treatment efficiency due to the blockage do not occur. On the other hand, the upstream packed bed 21 decomposes a relatively high concentration of easily decomposable sulfur-based odor substance, so that there is a high possibility that microorganisms will grow and become clogged, but the upstream packed bed 21 has a large carrier. And the gap between the carriers is widened, so that even if a nodule is formed, the packed layer 21 is prevented from being clogged, and this also suppresses a decrease in the processing efficiency of deodorization. .

  As described above, according to the biological deodorization apparatus 1 of the present embodiment, the efficiency of the odor gas deodorization treatment can be improved, and accordingly, even if the volume of the downstream packed bed 31 is further reduced, Therefore, it is possible to reduce the size of the apparatus 1 by reducing the space of the downstream packed bed 31. In addition, since the deodorizing performance of the device 1 is enhanced and a larger amount of odorous substances can be decomposed than before, the odorous gas can be deodorized more reliably.

  As a result, since the concentration of the odorous substance in the gas at the outlet 12 can be lowered, the activated carbon adsorption tower, the mist separator, and the deodorizing fan that are necessary for removing the residual odorous substance in the conventional apparatus can be omitted. Accordingly, the number of devices can be reduced to reduce the energy consumption and maintenance work of the entire apparatus, and the periodic replacement of consumption materials such as activated carbon becomes unnecessary, so that the running cost of the apparatus 1 can be reduced. it can. Moreover, since the apparatus 1 can be reduced in size and the installation space can be reduced, the equipment cost of the apparatus 1 can also be reduced.

  However, an activated carbon adsorption tower may be required depending on the facility where the biological deodorizing apparatus 1 is installed, the type of gas to be processed, and the like. However, according to the biological deodorization apparatus 1 of the present embodiment, as described above, the deodorization treatment chamber 30 (downstream side filling) that treats a hardly decomposable sulfur-based odor substance that generates a small amount of sulfuric acid and is less likely to lower the pH. Since the layer 31) is disposed on the gas outlet 12 side, the amount of water spray required for removing sulfuric acid or the like can be made smaller than that in the upstream deodorization treatment chamber 20 (upstream packed bed 21). Therefore, it is possible to reduce the mist in the exhaust gas, omitting the mist separator or the like, or reducing the amount of moisture adsorbed on the activated carbon of the activated carbon adsorption tower, thereby extending the life of the activated carbon, that is, The number of exchanges and the like can be reduced. Accordingly, even in such a case, the equipment cost and running cost can be reduced.

  Further, in this biological deodorization apparatus 1, since the carrier is formed of porous ceramic having a large number of communication holes, the surface area of the carrier in contact with the odor gas can be increased, and the number of microorganisms can be increased. Therefore, the odorous substance can be effectively decomposed to improve the odorous gas deodorizing treatment efficiency and the deodorizing performance. At the same time, porous ceramics have a high detergency product (sulfuric acid) washability due to the shape of the communicating holes, so that sulfuric acid can be efficiently discharged out of the system only by intermittent watering, and high deodorization efficiency and performance can be achieved for a long time Can be maintained over a period of time.

  In addition, since the water retention capacity of the carrier is also high, it is possible to more reliably retain the moisture on the surface of the carrier, which is necessary for the inhabiting of microorganisms, the absorption of odorous substances, and the delivery to microorganisms, and the deodorization efficiency and performance decline. Can also be prevented. In addition, since the strength and durability of the carrier are increased, it is not necessary to replace or replenish the carrier due to deterioration, reducing running costs, and preventing the consolidation of the carrier and the accompanying increase in odor gas pressure loss. In addition, it is possible to prevent the odorous gas from becoming difficult to flow and to prevent a reduction in processing efficiency and performance.

  Here, normal tap water, river water, or the like may be used for watering the biological deodorization apparatus 1. However, when the apparatus 1 is installed in a sewage treatment plant, for example, the amount of water is relatively large and the pH is high. Although it is preferable to use sand filtered water having a high buffering capacity and low suspended solids, when the required amount of sand filtered water cannot be ensured, strained secondary treated water may be used. Moreover, although this apparatus 1 employ | adopted what is called a transient watering system which discharges the water sprayed without reusing, when the water for watering cannot be ensured, the said conventional biological deodorizing apparatus 100 shown in FIG. Similarly to the above, the produced sulfuric acid may be neutralized with caustic soda or the like, and recycled while being circulated while maintaining the pH of water within a predetermined range.

  In this embodiment, the carrier is formed in a substantially columnar shape, but may be formed in a spherical shape, a block shape, or other shapes such as a ring shape or a cylindrical shape. In addition to the porous ceramic, the carrier is, for example, a porous molded body made of synthetic resin such as polypropylene or urethane, a sponge-like molded body, pumice, lava, ALC (Autoclaved Light-weight aerated Concrete), etc. It may be formed of concrete, peat with a large surface area, charcoal, wood chips, activated carbon or other porous materials, such as pitch-based, acrylic-based, cellulose-based, phenol-based fibers or fibrous activated carbon. It may be formed in a lump shape or filled with each fiber as it is to form a carrier.

  Furthermore, in the present embodiment, the biological deodorization apparatus 1 has been described by taking as an example a two-column integrated structure in which the biological deodorization tower 10 is divided into two chambers by one partition wall 13, but the biological deodorization tower is provided with a partition wall. Without a two-column structure, two packed beds are connected in parallel in the vertical and horizontal directions in the tower along the gas flow path, and the two towers are connected by pipes. An upstream and downstream packed bed similar to the present embodiment can also be formed in the apparatus. In addition, it is equipped with a three-tower structure device that sequentially passes odor gas through three deodorization treatment chambers, two upstream deodorization treatment chambers, and one downstream deodorization treatment chamber that communicates with any of them, and upstream deodorization chambers. The present invention can also be applied to an apparatus having three or more towers having a packed bed on the upstream side and the downstream side, such as an apparatus having a three-column switching structure in which processing chambers are alternately switched.

It is a sectional side view which shows schematic structure of the biological deodorizing apparatus of this embodiment. It is a FF arrow line view of FIG. It is a sectional side view which shows schematic structure of the conventional biological deodorizing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Biological deodorizing device, 10 ... Biological deodorizing tower, 11 ... Inlet, 12 ... Outlet, 13 ... Partition, 14 ... Gas passage, 15 ... Water passage , 16 ... overflow pipe, 17 ... drain, 20 ... upstream deodorization treatment chamber, 21 ... upstream filling layer, 22 ... water tank, 30 ... downstream deodorization treatment chamber, DESCRIPTION OF SYMBOLS 31 ... Downstream packed bed, 32 ... Water storage tank, 40 ... Sprinkling device, 41 ... Water flow rate adjustment means, 41A ... Flow meter, 41B ... Valve, 42 ... Sprinkling Water pipe, 43... Motorized valve, 44.

Claims (8)

A gas flow path for distributing an odor gas containing a sulfur-based odor substance;
An upstream packed bed filled with a carrier that is arranged upstream of the gas flow path and is mainly fixed with microorganisms that decompose the easily decomposable sulfur-based odor substance;
A downstream packed bed filled with a carrier that is arranged on the downstream side of the gas flow path and mainly immobilized with microorganisms that decompose the hardly decomposable sulfur odor substance,
A biological deodorization apparatus for performing deodorization by sequentially passing the odor gas through the upstream packed bed and the downstream packed bed;
The value obtained by dividing the total surface area of the carrier packed in the upstream packed bed by the volume of the upstream packed bed is E1, and the total surface area of the carrier packed in the downstream packed bed is divided by the volume of the downstream packed bed. When the value is E2,
A biological deodorization apparatus characterized by satisfying E1 <E2. The biological deodorization device according to claim 1,
The biological deodorization apparatus characterized in that the total surface area of the carrier packed in the downstream packed bed is larger than the total surface area of the carrier packed in the upstream packed bed. The biological deodorization apparatus according to claim 1 or 2,
The biological deodorization apparatus, wherein the carrier of the upstream packed bed and the downstream packed bed is formed in a granular shape, and the carrier of the downstream packed bed is formed in a smaller particle than the carrier of the upstream packed bed . In the biological deodorization device according to any one of claims 1 to 3,
The biological deodorization apparatus, wherein the carrier of the upstream packed bed and the downstream packed bed is made of a porous ceramic. The biological deodorization device according to any one of claims 1 to 4,
An upstream pH adjusting means for watering the upstream packed bed and adjusting the pH of the upstream packed bed;
A downstream pH adjusting means for sprinkling water on the downstream packed bed and adjusting the pH of the downstream packed bed;
The biological deodorization apparatus characterized by controlling pH of the said upstream packed bed and the said downstream packed bed independently. Odor gas containing sulfur-based odor substance is sequentially passed through an upstream packed bed and a downstream packed bed filled with a carrier on which microorganisms are immobilized, and the sulfur-based odorous substance is decomposed by the microorganisms immobilized on the carrier. A biological deodorization method for deodorizing
Passing the odor gas through the upstream packed bed and decomposing mainly the easily decomposable sulfur-based odor substance;
Passing the odor gas through the downstream side packed bed, and mainly decomposing the hardly decomposable sulfur-based odor substance,
The value obtained by dividing the total surface area of the carrier packed in the upstream packed bed by the volume of the upstream packed bed is E1, and the total surface area of the carrier packed in the downstream packed bed is divided by the volume of the downstream packed bed. A biological deodorization method characterized in that E1 <E2 when the value is E2. The biological deodorization method according to claim 6,
A biological deodorization method, wherein the total surface area of the carrier packed in the downstream packed bed is made larger than the total surface area of the carrier packed in the upstream packed bed. The biological deodorization method according to claim 6 or 7,
Watering the upstream packed bed and adjusting the pH of the upstream packed bed to 0.5 or more and 5 or less;
And a step of watering the downstream packed bed and adjusting the pH of the downstream packed bed to 6 or more and 8 or less.

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