JP2003154230A - Biological deodorizing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological deodorizing apparatus using lightweight packed beds having a significant microorganism sticking and carrying effect and a significant malodorous component removing effect and free of increase of pressure drop due to sprinkling of washing water. SOLUTION: In the biological deodorizing apparatus 1 with a malodorous gas feed pipe 2 at the bottom, a treated gas discharge pipe 8 at the top and packed beds 3, 4 carrying microorganisms which degrade the malodorous components of malodorous gas within the apparatus, the packed beds are formed of a packing material obtained by coating the surfaces of porous resin moldings with an acetalized product of polyvinyl alcohol and the porous resin moldings are foamed moldings of polyurethane, polystyrene, polypropylene, polyethylene or polyacetal and preferably have an open cell structure in which the inlet and outlet of each cell are open at different portions of the surface of the resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biological deodorizing device,
In particular, the present invention relates to a biological deodorization device that deodorizes biologically degrading malodorous components of malodorous gas generated from human waste treatment plants, sewage treatment plants, and other factories by microorganisms such as activated sludge.

[0002]

2. Description of the Related Art Malodorous components of malodorous gas generated from human waste treatment plants and sewage treatment plants are hydrogen sulfide, methyl mercaptan,
Examples include methyl sulfide, methyl disulfide, ammonia and the like. Among these, the relatively high concentration is hydrogen sulfide (5-50 pp
m) and ammonia (1 to 10 ppm). In a biological deodorizer, these components are relatively easy to decompose, so degradation efficiency is less of a problem, but microbial sludge and elemental sulfur produced by the decomposition of these components accumulate in the packed bed and block. There is a problem that causes. On the other hand, although the concentration of methyl mercaptan (0.5 to 5 ppm), methyl sulfide, and methyl disulfide (each 1 ppm or less) is low, the decomposition efficiency of these components often causes a problem because they are difficult to decompose.

In order to deodorize such a malodorous gas, a porous resin molding such as a hydrophobic (not absorbing water) polyurethane sponge three-dimensional network granules carrying microorganisms for decomposing malodorous components inside the treatment tower. It has been conventionally practiced to provide a packing layer for the body, to ventilate a malodorous gas in an upward flow through this packing layer, and to oxidize and decompose the malodorous components by the microorganisms carried by the sponge particles. The use of a porous resin molded body as the filling layer has a large surface area per unit volume, is lightweight, and can be easily molded into an arbitrary shape. It is possible to suppress the accumulation of sludge and elemental sulfur, etc., and it is possible to smoothly flow down the washing water sprinkled from the top of the packed bed. Moreover, even if the washing water is sprinkled from above, it does not deform or consolidate. This is because the filler has excellent features such as that. Although the conventional foamable resin molded body has the excellent characteristics as described above, it has a problem that the adhesion of microorganisms at the initial stage of operation is poor. Therefore, there is a problem that the startup period until the initial deodorizing performance is exhibited becomes long.

[0004]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, the present invention has a large effect of supporting microorganisms for decomposing malodorous components and an effect of removing malodorous components, is lightweight, and is not compacted by washing water. An object is to provide a biological deodorizing device using a layer.

[0005]

In order to solve the above problems, in the present invention, a microorganism for decomposing a malodorous component of a malodorous gas inside, an air supply pipe for a malodorous gas at the bottom, an exhaust pipe for a processing gas at the top. In a biological deodorizing device provided with a packed layer carrying a carrier, and a sprinkling pipe for spraying washing water to the packed layer, the packing layer is a packing material in which the surface of a porous resin molding is coated with an acetalized product of polyvinyl alcohol. It was formed in. In the biological deodorization device, the porous resin molded body is a foamed molded product of polyurethane, polystyrene, polypropylene, polyethylene or polyacetal, and the porous resin molded body has an inlet and an outlet at different sites on the surface of the resin. It should have an open pore structure.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a foamable resin molding,
The filler is not decomposed by microorganisms, is lightweight and has low ventilation resistance, is light, does not consolidate with washing water, and makes good use of the excellent characteristics such as allowing washing water to flow down smoothly, and microorganisms As a result of pursuing a method of improving the adhesiveness, it was found that the reason why the microorganisms are difficult to adhere is that the foamable resin molded body is extremely hydrophobic, and the polyvinyl alcohol (PV
When the acetalized product of A) is coated, microorganisms grow extremely effectively on the surface, the foamable resin molded body has strength, and the amount of absorbing water is moderate, so that the self-weight of the filler is The present invention has been completed by finding that the filling layer does not consolidate and the gas ventilation resistance does not increase. On the other hand, if the filler itself is made of a porous, water-swellable, and hydrophilic resin, the compressive strength of the filler itself is small and a large amount of water is absorbed. It was confirmed that the lower part is compressed by the weight of the filler containing water in the upper part, and the gas ventilation resistance is increased.

Therefore, the porous resin molding of the present invention has such a compressive strength that the packed bed is not compressed even when it is packed to a height of 30 cm or more, and the material of the resin is Although it is not limited in itself, typical examples thereof include foamed molded products such as polyurethane, polystyrene, polypropylene, polyethylene, and polyacetal. There is also a method of using a plate-like fiber aggregate composed of a fiber containing a water-resistant synthetic fiber and a binder, as described in JP-A-7-284630, instead of these porous resin moldings. The aggregate can have an extremely large specific surface area by collecting the fibers in a bulky manner, but it is difficult to impart three-dimensional strength to the aggregate. On the other hand, if the density of the fibers is increased to have strength, not only the specific surface area becomes smaller, but also it is difficult to discharge excess solid matter, smooth gas flow and discharge of sprinkled water. Become. Therefore, considering the balance between the optimum specific surface area and the strength / porosity of the fiber,
It is necessary to adjust to the optimum fiber density, but there is a problem that processing becomes complicated.

On the other hand, in the case of a porous resin, not only the shape and size, but also the specific surface area can be adjusted by controlling the conditions at the time of molding, for example, the foaming rate in the case of foam molding. Therefore, the optimum filler can be easily manufactured in consideration of the optimum balance between the specific surface area and the strength / porosity. The shape of the porous resin is not particularly limited, and may be, for example, a powder, a two-dimensional shape, or a three-dimensional shape. The porous resin has an amorphous shape (crushed shape), a granular shape, a pellet shape, a spherical shape, a polyhedron shape (dices shape), a honeycomb shape, a sheet shape, a block shape, a strip shape, a hollow cylinder shape, a saddle shape, or the like. May be. The structure of the porous resin may be porous (porous structure) having a large number of pores (or pores), and may have network-like pores (or pores) of a three-dimensional network structure.

The size of the porous resin is not particularly limited, and usually has an average diameter of 1 to 50 mm, preferably 5 to 40.
A resin having a size of about mm may be randomly filled, or a block having a side length of about 500 to 2000 mm may be integrally filled. The average pore diameter of the pores (or pores) of the porous resin is, for example, 0.01 to 3 mm, preferably 0.03
It is about 1 mm. The pores (pores) may partially exist as closed cells in the resin, but preferably have a continuous pore structure in which the inlet and the outlet are open at least at different sites on the surface of the resin. In particular, it is preferable that the pores (pores) form communication holes that are open (or penetrate) at different portions of the resin, and may communicate with each other in the form of a mesh inside the resin. In order to coat the sponge skeleton of the polyurethane sponge having a three-dimensional network structure, which is one of the porous resins, with PVA, for example, the following may be performed.

That is, the polyurethane sponge granules or blocks are immersed in a PVA aqueous solution and then pulled up,
Next, after soaking in an acidic formalin aqueous solution and leaving it for a few hours, a polyurethane sponge skeleton coated with a PVA acetal compound is completed. In addition, PVA
Since it has a surface-active ability, it can be attached to polyurethane by the above method, but as a result of studying a more suitable coating method, first, the polyurethane sponge was dipped in an aqueous surfactant solution to remove the hydrophobic group of the surfactant. When it is adsorbed on the polyurethane surface and immersed in an aqueous PVA solution with the hydrophilic groups oriented outward, P is extremely effective.
It was observed that VA was attached to the polyurethane sponge skeleton. After that, when immersed in an aqueous formalin solution, P
A polyurethane sponge with a sufficient amount of VA acetal compound attached is completed.

Next, a description will be given with reference to the sectional configuration diagram of the biological deodorizing apparatus of the present invention shown in FIG. In FIG. 1, 1 is a treatment tower, an air supply pipe 2 for a malodorous gas at the bottom, a packing layer 3 and 4 in two upper and lower stages, and a sprinkling pipe 5 for spraying washing water from each packing layer 3 and 4 from above. 6 is provided, and 8 is an exhaust pipe for processing gas. The filling layers 3 and 4 are composed of a porous resin molded body coated with a PVA acetalized product (which may be cut into particles having a particle diameter of about 10 mm or a block shape having a side length of several meters). Since the surface of the filler (porous resin molded body) 6 that constitutes the filling layers 3 and 4 has become extremely hydrophilic due to the PVA acetalization treatment, microorganisms that decompose the malodorous components into the inside and the surface of the filling material quickly Moreover, a large amount can be supported.

Once the packed beds 3 and 4 have been constructed, sprinkler tubes 5 and 6
In the packed beds 3 and 4, diluted water for activated sludge, treated water for activated sludge,
Disperse river water, etc., inoculate microorganisms such as nitrifying bacteria, sulfur-oxidizing bacteria, etc., and supply malodorous gas from the air supply pipe 2 to the bottom of the treatment tower 1, and then the lower packed bed 3, then the upper packed bed 3 The packed bed 4 is vented with an upward flow. Therefore, not only hydrogen sulfide and ammonia but also hard-to-decompose components such as methyl mercaptan, methyl sulfide and methyl disulfide can be efficiently removed. Moreover, since the porous resin molded body has excellent acid resistance, there is no reduction in strength due to SO ₄ ^2- or the like generated by a malodorous gas. Furthermore, SO ₄ ²⁻ , NH generated by oxidative decomposition of malodorous substances
_{Even if a} large amount of cleaning water for washing away ₄ ⁺ , NO ₂ ⁻ , NO ₃ ^−, etc. is sprayed from the sprinkling pipe 5 to the packed bed 3, the packing material forming the packed bed 3 is an open cell and has a compressive strength. Since it is large, it does not collapse, and the wash water smoothly flows down along with the product inside the granules and in the gap between the fluids, flows down to the bottom of the treatment tower, and is discharged from the drain pipe 9. Therefore, even if washing is performed with a large amount of washing water, the packed bed 3 does not consolidate, and the washing water flowing down the bed does not become a resistance against the malodorous gas vented in the upward flow, so that the pressure loss is reduced. Does not increase.

[0013]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 A filler having the surface of the porous resin molding of the present invention coated with an acetalized product of PVA was produced by the following method. That is, 10% by weight of PVA of polyurethane sponge
After being dipped in the aqueous solution, it was dipped in a saturated solution of sodium tetraborate to coat the surface of the polyurethane sponge with PVA. Next, after heat treatment at 105 ° C. for 5 minutes, the PVA coated on the surface of the polyurethane sponge was acetalized by being immersed in formalin. The compressive strength (25% deformation) of the manufactured filler was 1200 kPa. This packing material was filled in the packed bed of the biological deodorizing apparatus shown in FIG. 1, and the odor generated from the water treatment process of the sewage treatment facility was used as a raw gas for deodorization.

The operating conditions are as follows. Hydrogen sulfide concentration: 2ppm Methyl mercaptan concentration: 0.04ppm Methyl sulfide concentration: 0.013ppm Methyl disulfide concentration: 0.0025ppm Temperature: 24 ° C Superficial velocity: 400hr ^-1 Superficial linear velocity: 0.22m / sec Water sprinkling Frequency: Liquid gas ratio when sprinkling water for 1 minute for 2 minutes: 3 L / m ³ After 20 days from the start of deodorizing treatment, the malodorous substance concentration of the treated gas is 0.001 ppm or less of hydrogen sulfide, 0.001 ppm or less of methyl mercaptan, and methyl sulfide. 0.001pp
m or less and methyl disulfide 0.001 ppm or less.
Thereafter, stable malodorous substance removal performance was exhibited for a long period of time, and the pressure loss of the packed bed was stable at a low value of about 100 Pa. Table 1 shows the deodorization results one month after the start of deodorization treatment.
Shown in.

Comparative Example 1 The packed bed of the biological deodorizer shown in FIG. 1 has a compressive strength of 70 kP.
The deodorizing treatment was performed under the same conditions as in Example 1 except that the PVA sponge of a. After 20 days from the start of the deodorizing treatment, the malodor concentration of the treated gas is 0.001 ppm or less of hydrogen sulfide, 0001 ppm or less of methyl mercaptan, 0.001 ppm or less of methyl sulfide, and 0.001 pp of methyl disulfide.
m was less than or equal to m, and the odorous substance removal performance equivalent to that of Example 1 was exhibited. However, the packed bed was gradually consolidated, and the pressure loss of the packed bed was about 150 Pa at the beginning of the operation, but increased to 500 Pa after one month.

COMPARATIVE EXAMPLE 2 The packed bed of the biological deodorizer shown in FIG.
The deodorizing treatment was performed under the same conditions as in Example 1 except that the polyurethane sponge having kPa was filled. After 20 days from the start of the deodorizing process, the malodor concentration of the treated gas was 0.001 of hydrogen sulfide.
ppm or less, methyl mercaptan 0.004 ppm, methyl sulfide 0.007 ppm, methyl disulfide 0.0015
It was ppm, which was a higher value than those in Example 1 and Comparative Example 1. The pressure loss of the packed bed was stable at a low value of about 100 Pa. Table 1 shows the deodorizing results one month after the start of the deodorizing treatment.

[0017]

[Table 1]

[0018]

As is apparent from the above, according to the present invention, the filling layer 3 formed by coating the surface of the porous resin molded body with the PVA acetalized product makes it extremely easy for microorganisms to adhere, and It is not compressed and pressure loss is not increased, and the washing water is allowed to flow smoothly, so that the layer 3
Most of the malodorous components of the malodorous gas flowing upwards can be decomposed and deodorized.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing an example of a biological deodorizing apparatus of the present invention.

[Explanation of symbols]

1: Treatment tower, 2: Air supply pipe, 3, 4: Packed bed, 5, 6: Sprinkling pipe to packed bed, 7: PVA on surface of porous resin molding
Filler coated with acetalized product, 8: exhaust pipe, 9: drain pipe

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigeki Yamashita             11-1 Haneda Asahi-cho, Ota-ku, Tokyo Co., Ltd.             Inside the EBARA CORPORATION (72) Inventor Toshihiro Tanaka             11-1 Haneda Asahi-cho, Ota-ku, Tokyo Co., Ltd.             Inside the EBARA CORPORATION F-term (reference) 4C080 AA07 BB02 CC03 CC04 CC05                       CC08 CC13 HH05 HH09 JJ03                       KK06 KK08 LL04 LL10 MM33                       NN25 NN27 NN28 QQ03 QQ17                 4D002 AA03 AA05 AA06 AA13 AB02                       AC10 BA05 BA17 CA07 DA59                       EA02 EA09 EA13 GA03 GB12                       HA01

Claims (3)

[Claims] 1. A malodorous gas supply pipe at the bottom, a processing gas exhaust pipe at the top, a packing layer carrying microorganisms that decompose the malodorous component of the malodorous gas inside, and washing water is sprayed on the packing layer. A biological deodorizing device comprising a water sprinkling pipe, wherein the filling layer is formed of a filling material in which a surface of a porous resin molded body is coated with an acetalized product of polyvinyl alcohol. 2. The biological deodorizing device according to claim 1, wherein the porous resin molding is a foam molding of polyurethane, polystyrene, polypropylene, polyethylene or polyacetal. 3. The biological deodorizing device according to claim 1, wherein the porous resin molding has a continuous pore structure in which an inlet and an outlet are open at different portions of the surface of the resin.