JP2012011288A - Deodorizing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently remove malodor components contained in malodorous gas.SOLUTION: A deodorizing device is a device for deodorizing gas containing malodor components. The deodorizing device includes a deodorization tower filled with a carrier for biological deodorization. The deodorization tower is installed on the upper stage of an aeration tank side wall or on the upper stage of a passage part between aeration tanks. The carrier for biological deodorization is a fiber bundle comprising activated carbon fibers and thermoplastic synthetic fiber and has a bulk density of 0.05-0.15 g/cm, a porosity of 70-98%, a maximum cross section diameter of 5-25 mm, and a length of 5-30 mm.

Description

  The present invention relates to a deodorizing apparatus, for example, a deodorizing apparatus for malodorous gas containing hydrogen sulfide, methyl mercaptan, methyl sulfide, methyl disulfide, ammonia, organic acid and the like generated in large quantities from an aeration tank.

  One of the major problems of sewage treatment plants has been complaints of bad odors from neighboring residents. Therefore, in each sewage treatment plant, the first settling basin with strong odor is covered, and the generated bad odor gas is collected in one place by the odor duct, and the deodorization equipment using chemical cleaning method, activated carbon adsorption method or biological deodorization method is used. After removing malodorous components, they are released from the deodorizing fan into the atmosphere.

  Among them, the biological deodorization method is a method in which microorganisms that propagate using odor components as nutrient sources are supported on the surface of the contact material, and the odor components are decomposed and deodorized by the microorganisms. Soil, plastic, ceramic and processed products thereof, and those in which microorganisms are fixed are used (Patent Documents 1, 2, and 3).

JP-A-10-137536 Japanese Patent Application Laid-Open No. 2002-336639 JP-A-8-10557

  However, in order to improve the deodorizing performance, it is necessary to use a dense biological deodorizing carrier having a large contact surface area with the gas and high processing efficiency, so that the pressure loss during gas passage increases. In addition, when the biological deodorizing carrier filled in the deodorizing device is rough, the pressure loss during gas passage is low, and when the deodorizing device is installed in an aeration tank, for example, the air pressure blown into the tank is used. It can be easily passed. However, in such a case, since the contact area with the gas is small, a large amount of gas that cannot be contacted with the carrier, that is, the contact material and has not been deodorized is released into the atmosphere. In order to prevent this, it is necessary to take measures such as making the deodorization tower large and increasing the chance of contact with gas.

  An object of the present invention is to enable efficient removal of malodorous components contained in gas generated from an aeration tank or the like.

The inventors of the present invention diligently studied to solve the above-mentioned problems, and the summary of the achieved invention is an apparatus for deodorizing a gas containing a malodorous component, which is a biological deodorization packed with a biological deodorizing carrier. The biological deodorization tower is provided at the upper stage of the side wall of the aeration tank or the upper stage of the passage part between the aeration tanks, and the biological deodorization carrier is a fiber converging body including activated carbon fibers and thermoplastic synthetic fibers. The deodorizing apparatus is characterized by having a bulk density of 0.05 to 0.15 g / cm ³ , a porosity of 70 to 98%, a maximum cross-sectional diameter of 5 to 25 mm, and a length of 5 to 30 mm.

According to the present invention, by using a filler made of activated carbon fiber as a microbial carrier, it is possible to obtain a biological deodorizing effect due to microorganisms combined with an adsorption effect, which enables efficient deodorization and prevents malodorous gas from In addition to high-speed and low-cost operation costs, the carrier is a fiber converging body containing activated carbon fibers and thermoplastic synthetic fibers, and has a bulk density of 0.05 to 0.15 g / cm ^3. Further, since the porosity is 70 to 98%, deodorization can be efficiently performed in a state where the pressure loss is small.

  Furthermore, according to the present invention, since the biological deodorization tower is provided on the upper stage of the side wall of the aeration tank or the upper stage of the passage part between the aeration tanks, it is possible to prevent the problem of load resistance due to the weight of the biological deodorization tower. . Further, since the odor duct to the biological deodorization tower is very short, there is almost no temperature change while the gas to be treated flows through the odor duct, and the deodorization performance can be maintained in a good state.

It is a partially cutaway perspective view of an example of a biological deodorization tower and its peripheral part. It is the schematic which shows the example of the deodorizing apparatus provided with the biological deodorizing tower of FIG.

Hereinafter, the present invention will be described in detail.
In the present invention, it is necessary to use a molded body mainly composed of activated carbon fibers and thermoplastic synthetic fibers as a contact material that is packed in a biological deodorization tower and immobilizes microorganisms. The activated carbon fiber used in the present invention is made of coal pitch, petroleum pitch, rayon, phenol, acrylic, vinylon-based material or cellulosic material, etc., and is infusible and activated by ordinary methods to form fine pores. The specific surface area is preferably 500 m ² / g or more as measured by the BET method. When the specific surface area is less than 500 m ² / g, the pores become small and contact with the odor component becomes difficult.

This contact material is in the form of a fiber converging body in which activated carbon fibers and thermoplastic synthetic fibers are mixed to form a plurality of fiber bundles.
As the thermoplastic synthetic fiber constituting the filler together with the activated carbon fiber, for example, a single component fiber made of polyester, nylon, polyethylene, polypropylene, copolymerized polyester, or the like, or polyester for the core and polyethylene for the sheath Core-sheath type composite fibers using polypropylene, copolyester and the like.

  The mixing mass ratio of the activated carbon fiber and the thermoplastic synthetic fiber is preferably in the range of 90:10 to 10:90, particularly 85:15 to 15:85. If the ratio of the activated carbon fiber is too large, the moldability of the structure or the filler is deteriorated, and conversely if it is too small, the contact with the odor component is deteriorated.

  The fiber converging body used in the present invention, after opening and mixing the activated carbon fiber, to form a fiber bundle, heat-treating this fiber bundle and bonding between the fibers with a thermoplastic synthetic fiber to form a rod, Subsequently, it can obtain by cutting to arbitrary length.

  As for the size of the rod-like fiber converging body, the maximum diameter of the cross section is required to be 5 to 25 mm, and the range of 8 to 20 mm is preferable. In addition, a rod-shaped fiber converging body having a circular, elliptical, donut-shaped, trilobal, cross-shaped or star-shaped cross section is easy to handle and suitable as a biological deodorizing carrier. The maximum diameter here means the diameter in the case of a spherical shape or a donut shape, the length of the major axis in the case of an ellipse shape, and the maximum length in the case of other shapes. The length of the rod-like fiber converging body needs to be 5 to 30 mm, and preferably in the range of 10 to 20 mm.

  If the maximum diameter and length are too large beyond the above range, the pressure loss during the passage of gas is low, but the processing efficiency decreases because the contact area with the gas is small. On the other hand, if the rod-like fiber converging body is too small beyond the above range, the pressure loss at the time of gas passage is large, and for example, natural ventilation using the blowing air pressure in the aeration tank becomes difficult.

In the present invention, the bulk density of the fiber converging body needs to be 0.05 to 0.15 g / cm ³ . When the bulk density is larger than 0.15 g / cm ^{3, the} carrier formed by the fiber converging body becomes too dense, the porosity is lowered, the adhesion capacity of microorganisms is reduced, and the processing efficiency is lowered. It becomes. Furthermore, the weight of the apparatus becomes heavier, and the practicality of the apparatus is lowered because the apparatus is limited in place. On the other hand, when the bulk density is less than 0.05 g / cm ³ , the contact efficiency with the gas to be processed decreases, leading to a large decrease in processing efficiency. For this reason, the bulk density is preferably in the range of 0.05 to 0.085 g / cm ³ .

  The porosity of the rod-like fiber converging body needs to be 70 to 98%. This porosity is related not only to air permeability and strength but also to the amount of water retained. When the porosity is greater than 98%, the carrier formed by the fiber converging body becomes brittle. The carrier may be crushed and the practicality is reduced. When the porosity is less than 70%, in addition to poor air permeability, the amount of water retained is also reduced, and the influence of watering stop greatly affects the deodorization performance. For this reason, the range of 80 to 95% is preferable.

  FIG. 1 is a diagram illustrating an example of a biological deodorization tower and its peripheral part. In FIG. 1, a biological deodorization tower 1 is provided with a packed bed 2 filled with a biological deodorizing carrier, a sprinkler 3 above the packed bed 2, and a water receiving tank below the packed bed 2. 4 is arranged. The malodorous gas inlet 5 is communicated with the space in the upper part of the water receiving tank 4, and the bottom of the water receiving tank 4 is used for discharging water flowing down from the packed bed 2 based on the water sprayed from the water sprinkler 3. A drain port 6 is communicated. An exhaust port 7 is provided at a position above the sprinkler 3. A plurality of packed layers 2 may be arranged in the vertical direction and in parallel, or may be a plurality of three or more stages.

  According to said structure, the surface of the support | carrier is hold | maintained in a moist state by arrange | positioning the water sprinkler 3 above the packed bed 2 filled with the biological deodorizing support | carrier, and spraying water continuously or intermittently. Adhesion and propagation are promoted and oxidation products are washed away. In the case of intermittent watering, it is appropriate that the watering interval is about once every 0.5 to 4 hours, and the watering time per time varies depending on the shape of the watering device 3 and the amount of discharged water. 2 to 15 minutes is appropriate. In addition, when there are a plurality of packed beds 2, a sprinkler 3 may be arranged for each packed bed 2, or all packed beds 2 may be sprinkled with one sprinkler 3.

The effect of deodorization varies depending on the type and concentration of the odor component, but is determined by the bad odor gas ventilation rate (LV) and the superficial velocity (SV). According to the deodorizing apparatus of the present invention, as described above, the bulk density of the fiber converging body constituting the carrier is 0.01 to 0.10 g / cm ³ and its porosity is 70 to 98%. When the malodorous gas passage speed (LV) is 0.4 m / s or less, the pressure loss in the biological deodorization tower can be 15 mmH ₂ O or less.

As described above, the deodorizing apparatus of the present invention in which the biological deodorizing tower filled with the biological deodorizing carrier is provided in the upper stage of the side wall of the aeration tank or the upper stage of the passage part between the aeration tanks is blown into the aeration tank. It can be deodorized satisfactorily only by natural ventilation using air. If the superficial velocity is 2000 h ⁻¹ or less, good treatment can be performed.

  Moreover, since the carrier for biological deodorization of the biological deodorization tower is made of fiber, the specific surface area is large, the contact efficiency with the odorous substance is good, and the air permeability is excellent, so that the pressure loss is very small as described above. Therefore, even when a fan is used for ventilation, it can be operated with a low-power fan. In addition, the biological deodorizing carrier includes activated carbon fibers and thermoplastic synthetic fibers, and has a large porosity and can be reduced in weight. Therefore, for example, even if the packing layer 2 in FIG.

  FIG. 2 is a diagram illustrating a specific example of a deodorization apparatus including the biological deodorization tower 1. In FIG. 2, a plurality of aeration tanks 11, 11,... Are provided in series. Reference numeral 12 denotes a side wall of each aeration tank 11, and a passage 13 is formed between the side walls 12, 12 of the adjacent aeration tanks 11, 11. 14 is a cover for the aeration tank 11, 15 is a blower for aeration, and 16 is an air diffuser in the aeration tank 11. When processing is performed by providing a plurality of aeration tanks 11, 11,... In series, bad odor is likely to occur particularly in the first stage. For this reason, the cover 14 is provided only in the aeration tanks 11 and 11 of the first stage and the second stage.

  The biological deodorization tower 1 is arranged so as to straddle between the upper stages of the side walls 12 and 12 of the aeration tanks 11 and 11 of the adjacent first stage and second stage, that is, provided above the passage 13. Its weight is supported by the side walls 12, 12.

  In such a configuration, the gas to be treated 17 containing malodorous components generated in the aeration tank 7 is introduced into the biological deodorization tower 1 using the pressure of the blown air 18 from the air diffuser 12, and the inside thereof Is deodorized and discharged from the exhaust port 7 shown in FIG.

  As described above, the biological deodorization tower 1 is provided between the upper stages of the side walls 12 and 12 of the aeration tanks 11 and 11, and the weight is supported by the side walls 12 and 12. This is not a problem. Further, since the odor duct to the biological deodorization tower 1 is very short, there is almost no temperature change while the gas 17 to be treated flows through the odor duct, and the deodorization performance is maintained in a good state.

  Instead of the above, the biological deodorization tower 1 can be provided only on the upper stage of the side wall 12 of one aeration tank 11. In such a case, the biological deodorization tower 1 can be installed in a sewage treatment plant having only a single aeration tank.

Examples and Comparative Examples of the present invention are shown below.
Example 1
20% by mass of pitch-type fibrous activated carbon having a specific surface area of 1000 m ² / g and 80% by mass of core-sheath polyester unstretched fiber were opened and mixed with a carding machine to obtain a card sliver of 6 g per meter. This card sliver was heat-treated and then cut to obtain a six-leaf post-like fiber converging body having a maximum diameter of 8 mm and a length of 10 mm, which was used as a biological deodorizing carrier. This biological deodorizing carrier had a bulk density of 0.085 g / cm ³ and a porosity of 92%.

  After inoculating microorganisms on the biological deodorizing carrier, the biological deodorizing carrier was filled in the packed bed 2 in the biological deodorizing tower 1 to obtain a biological deodorizing tower as shown in FIG. This biological deodorization tower was provided in the upper stage of the passage part between the aeration tanks as shown in FIG. 2 to obtain a deodorization apparatus.

  Using the pressure of the blown air 18 in the aeration tank shown in FIG. 2, a gas to be treated 17 having a bad odor is introduced below the packed bed 2 inside the biological deodorizing tower 1 and is put into the atmosphere after the treatment. Released. The concentration of various sulfur compounds at that time was analyzed by gas chromatography. Table 1 shows the operating conditions, and Table 2 shows the processing results. The processing results were very good.

（実施例２）
比表面積１３００ｍ^２／ｇのピッチ系繊維状活性炭２５質量％と、芯鞘型ポリエステル未延伸繊維７５質量％とをカーディングマシンで開繊、混合し、1ｍあたり６ｇのカードスライバーとした。このカードスライバーを熱処理したのち切断し、最大直径８ｍｍ、長さ１０ｍｍの六葉柱状繊維収束体を得て、生物脱臭用担体とした。この生物脱臭用担体の嵩密度は０．０９０ｇ／ｃｍ^３、その空隙率は９２％であった。

(Example 2)
25% by mass of pitch-based fibrous activated carbon having a specific surface area of 1300 m ² / g and 75% by mass of core-sheath polyester unstretched fiber were opened and mixed with a carding machine to obtain a card sliver of 6 g per meter. This card sliver was heat-treated and then cut to obtain a six-leaf post-like fiber converging body having a maximum diameter of 8 mm and a length of 10 mm, which was used as a biological deodorizing carrier. This biological deodorizing carrier had a bulk density of 0.090 g / cm ³ and a porosity of 92%.

Using the biological deodorizing carrier composed of the six-leaf columnar fiber converging body obtained above, a biological deodorizing tower was obtained in the same manner as in Example 1, and malodorous gas was treated by a deodorizing apparatus using this biological deodorizing tower. The operating conditions were the same as in Example 1. The processing results are shown in Table 2, and the processing results were very good.
(Comparative Example 1)
A fiber of 100% by mass of the core-sheath polyester unstretched fiber was opened and mixed with a carding machine to obtain a card sliver of 6 g per meter. Then, a six-leaf columnar fiber converging body having a maximum diameter of 8 mm and a length of 8 mm produced from this card sliver was obtained and used as a biological deodorizing carrier. This biological deodorizing carrier had a bulk density of 0.105 g / cm ³ and a porosity of 92%.

Using the biological deodorization carrier comprising the six-leaf columnar fiber converging body obtained above, a biological deodorization tower was obtained in the same manner as in Example 1, and the gas to be treated was treated by a deodorization apparatus using this biological deodorization tower. . The operating conditions were the same as in Example 1. Although the treatment result is shown in Table 2, since the activated carbon fiber was not used, the treatment result was inferior to those of Examples 1 and 2.
(Comparative Example 2)
A fiber of 100% by mass of the core-sheath polyester unstretched fiber was opened and mixed with a carding machine to obtain a card sliver of 6 g per meter. Then, a six-leaf pillar-shaped fiber converging body having a maximum diameter of 25 mm and a length of 25 mm produced from this card sliver was obtained and used as a biological deodorizing carrier. This biological deodorization carrier had a bulk density of 0.04 g / cm ³ and a porosity of 95%.

Using the biological deodorization carrier comprising the six-leaf columnar fiber converging body obtained above, a biological deodorization tower was obtained in the same manner as in Example 1, and the gas to be treated was treated by a deodorization apparatus using this biological deodorization tower. . The operating conditions were the same as in Example 1. Although the treatment result is shown in Table 2, since the activated carbon fiber was not used and the bulk density was low, the treatment result was inferior to those of Examples 1 and 2.
(Comparative Example 3)
The same card sliver as in Example 1 was heat-treated and then cut to obtain a six-leaf post-like fiber converging body having an outer diameter of 25 mm and a length of 25 mm, which was used as a biological deodorizing carrier. This biological deodorizing carrier had a bulk density of 0.035 g / cm ³ and a porosity of 96%.

  Using the biological deodorization carrier comprising the six-leaf columnar fiber converging body obtained above, a biological deodorization tower was obtained in the same manner as in Example 1, and the gas to be treated was treated by a deodorization apparatus using this biological deodorization tower. . The operating conditions were the same as in Example 1. The processing results are shown in Table 2. Since the bulk density was low, the processing results were inferior to those of Examples 1 and 2.

DESCRIPTION OF SYMBOLS 1 Biological deodorization tower 2 Packing layer 3 Sprinkler 4 Water receiving tank 5 Odor gas introduction port 6 Drainage port 7 Exhaust port 11 Aeration tank 12 Side wall 13 Passage 14 Cover of aeration tank 11 15 Blower for aeration 16 Aeration tank Air diffuser in 11 17 Gas to be treated 18 Blowing air

Claims (1)

An apparatus for deodorizing a gas containing malodorous components, comprising a biological deodorization tower filled with a biological deodorization carrier, and this biological deodorization tower is located at the upper stage of the side wall of the aeration tank or the upper stage of the passage between the aeration tanks. The biological deodorizing carrier is a fiber converging body containing activated carbon fibers and thermoplastic synthetic fibers, and has a bulk density of 0.05 to 0.15 g / cm ³ , a porosity of 70 to 98%, and a cross section. The maximum deodorizing device has a diameter of 5 to 25 mm and a length of 5 to 30 mm.

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