JP3368705B2 - Apparatus and method for biological treatment of gas - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a treatment apparatus and a treatment method for biologically treating various gases including volatile organic compounds and odors.

[0002]

2. Description of the Related Art In order to biologically treat gas, a water-permeable support plate (plate) is horizontally provided in the lower part of a processing tank, and peat or compost is packed on the support plate to form a packed layer. Then, microorganisms adhere to this packed bed, and the raw gas to be treated is introduced into the bottom of the tank to make it flow upward in the packed bed, and when the raw gas flows upward in the packed bed, it adheres to the packed bed. BACKGROUND ART A processing apparatus that oxidizes and decomposes volatile organic compounds and odors in raw gas by the microorganisms and discharges the processing gas from the upper part of the processing tank to the outside has been conventionally known.

[0003]

In the above-mentioned conventional apparatus, it is necessary to intermittently sprinkle the packed bed from above during operation to replenish the water. It is to prevent water from evaporating moisture from the packed bed due to the upward flow of raw gas to dry the carrier of the microorganisms and to prevent the microorganisms from losing their activity, and to promote the growth of the microorganisms and increase their activity. This is because only organic compounds dissolved in water in the raw gas can be absorbed. Therefore, during operation, a sprinkler mechanism for sprinkling water in the packed bed must be incorporated in the apparatus usually every 30 minutes to 1 hour, which complicates the apparatus and increases the cost. Also, since the packed bed contains water due to water sprinkling, it will be consolidated in a short period of time after operation and the head loss will increase,
Frequently, the packed bed must be taken out and a new packed bed must be recreated in the bath. Furthermore, a support plate that supports the packed bed from below is required.Since the packed bed contains water and greatly increases the weight, the treatment tank and the supporting board have a complicated structure in order to have sufficient strength to withstand the weight. Become.

[0004]

The present invention was developed for the purpose of obtaining a gas biological treatment apparatus and method which do not have the above-mentioned problems. The biological treatment device is composed of a treatment tank in which water is stored at the bottom and a floating carrier to which microorganisms are adhered, and the floating carrier emits water.
Molded with Styrofoam or closed cell polyurethane foam
The granular material is a granular material, the lower part of the packed layer composed of the floating carrier is in a floating state in which it is immersed in the water in the treatment tank, and the packed layer above the immersed part is supported by buoyancy. In the state, it is equipped with a gas introducing means for introducing the raw gas into the water in the lower part of the processing tank, and a processing gas discharging means for discharging the processing gas from above the packed bed in the processing tank to the outside of the tank. Characterize. In this case, the water depth of the treatment tank is 5-1
00 cm, the height of the packed bed is 0.3-5 m,
The floatable carrier has a specific gravity of 0.01 to 0.2 and a particle size of 1 to 50.
It is preferable that the particles are mm mm in size, and it is preferable that a pressing plate is provided on the packed bed. The biological treatment method for gas according to claim 5 is that the raw gas is introduced into water stored in the lower portion of the treatment tank, and then the lower portion is immersed in the water of the treatment tank, which is composed of a floating carrier having microorganisms attached thereto. It is characterized in that air is circulated upward in the floating packed bed, and the gas aerated in the packed bed is discharged from above the packed bed to the outside of the tank.

[0005]

Embodiment In the illustrated embodiment, 10 is a treatment tank, 11
Is a water stored in the lower part of the treatment tank, 12 is a floating carrier having microorganisms attached thereto, and a filled layer filled in the treatment tank in a floating state in which the lower part is immersed in water in the treatment tank, 13 is a treatment tank A gas introduction pipe for introducing the raw gas into the water in the lower part of 14 is provided on the upper wall of the processing tank, and 14 is a processing gas discharge port for discharging the processing gas to the outside of the tank.

The floating carrier constituting the packed bed 12 has a specific gravity of 0.01 to 0.2 and a particle size of 1 to 50 mm, preferably 2
Styrofoam having a size of about 10 mm or a granular material formed of closed-cell polyurethane foam is used. The granular material may be a spherical body or a cube, or may be a crushed material having an arbitrary shape. Prevent the pressure loss from rising by keeping the filling condition constant,
Moreover, in order to uniformly attach the microorganisms and enhance the treatment efficiency, it is preferable to fill the particles with a uniform particle size.

The water 11 in the lower part of the treatment tank may be any of industrial water, well water, tap water, river water, etc., and the water depth is 5 to 100 c.
m, the bed height of the packed bed 12 is 0.3 to 5 m, and the lower part 12 'of the packed bed is in a state of being immersed below the water surface W of the water 11 due to the weight of the floating carrier constituting the packed bed, resulting in buoyancy. Supports the floating carrier of the packed bed above it.
After forming the packed bed in the treatment tank, the microorganisms sprinkle fungi such as activated sludge onto the packed bed from above, acclimate the microorganisms in the packed bed, and attach them to the floating carrier particles in a film form.

[0008] After forming a packed bed in the treatment tank which stores water in the lower part and inoculating the bacteria, raw gas is supplied from the gas introduction pipe 13 into the water in the tank. When the raw gas passes through the water 11 to increase the water content and then flows upward in the packed bed 12, the volatile organic compounds and odors in the gas are oxidatively decomposed by the microorganisms that have adhered and propagated to the treated gas. And is discharged from the discharge port 14 to the outside of the tank.

Since the raw gas flowing upward in the packed bed contains a large amount of water through the water 11, it prevents the microorganisms adhering to the floating carrier from drying and promotes the growth of the microorganisms to enhance the activity of the microorganisms. . In addition, the organic compound in the raw gas dissolves in the water content of the gas. Therefore, since the organic compound dissolved in the water in the gas is oxidatively decomposed by the highly active microorganism, the processing efficiency of the raw gas is extremely high.

Feed rate SV of raw gas through the introduction pipe 13
Varies depending on the concentration and type of gas, but is about 1 to 10
00 hr ^-1, preferably from 10 to 200 h ^-1. Further, it is preferable that the introduction pipe 13 is arranged so that the raw gas can be uniformly diffused over the entire lower surface of the packed bed 12.

Typical gases that can be treated by this biological treatment apparatus are hydrogen sulfide 1-1000 ppm, methyl mercaptan 1-100 ppm, and dimethyl sulfide 0.0.
01-0.1 ppm, dimethyl disulfide 0-0.
Sludge treatment exhaust gas containing 1 ppm, isopropyl alcohol 10 to 1000 ppm, methyl ethyl ketone 1
Exhaust gas from a semiconductor factory containing 0 to 100 ppm, methanol 5 to 30 ppm, xylene 1 to 10 ppm, chemical factory exhaust gas containing dimethyl sulfoxide 10 to 500 ppm, and dichloromethane 10 to 1000 ppm.

A glass column having a height of 1 m and an inner diameter of 50 mm is used as a treatment tank, and a floating carrier made of expanded polystyrene having a particle diameter of 3 mm is packed therein to form a packed layer having a layer height of 50 cm. K ₂ HPO ₄ as 1g
/ Stand, 0.5 g of NaH ₂ PO ₄ / stand, 2 of NH ₄ Cl
g / standing, MgSO ₄ · 7H ₂ O and 0.2 g / standing, CaC
l ₂ · 2H ₂ O and 0.2 g / stand and so as to dissolve, 10c the level of the water is injected from above the 200m elevation in the column
Then, 20 m of activated sludge (MLSS 1000 ppm) preliminarily acclimated with dimethyl sulfoxide was added in order to float the packed bed and float the floating carrier of the packed bed to prepare an experimental apparatus. One week after the microorganisms adhered to the floatable carrier in a film form, a gas containing 100 mg / liter of dimethylsulfoxide was introduced into the water at the bottom of the column at a rate of 70 liters / hour. The amount of oxide was 1 mg / cubic or less, and it was confirmed that the effect was sufficient.

When the raw gas flows upward in the packed bed, vertical gas passages are formed in the packed bed to prevent short passage of the raw gas. It is preferable to provide a holding plate 15 made of slate or the like. The restraining plate 15 may be brought into contact with the upper surface of the filling layer, or may be provided at a distance of about 10 cm.

The sprinkler pipe 1 is provided above the packed bed in the treatment tank.
6 is piped and water is sprinkled to wash the floating carrier constituting the packed bed. Unlike the water supply for moistening peat or compost, this water sprinkling is intended for cleaning the floating carrier, so it may be carried out when the pressure loss increases, and a large amount of water (50 to 500 cubic meters / m 3) can be obtained. ^It is effective to sprinkle ³ carriers) in a short time of about 0.5 to 5 minutes. Then, since the water level in the lower part inside the treatment tank rises due to water sprinkling, the overflow port 17 for discharging the amount of water sprinkled out of the tank.
Is installed to keep the water level at the bottom of the tank constant.

Since styrofoam and polyurethane foam are used for the floating carrier of the packed bed, since these are hydrophobic , they adsorb hydrophobic gas such as petroleum and gasoline, and biodegradability is improved.

Further, when the raw gas to be treated does not contain a nutrient source for microorganisms or is insufficient even if it does, the nutrient source is added to the water at the bottom of the treatment tank so that the raw gas passes through the water and the packed bed is passed. The microorganisms may be replenished at the time of upward flow to enhance the activity of the microorganisms.

[0017]

According to the present invention, since the packed bed is formed of the floatable carrier and is supported by the water stored in the lower part of the treatment tank in a floating state, a supporting plate for supporting the packed bed from below is not required. The processing tank does not need strength either. Since the packed bed made of the buoyant carrier is lightweight, the height of the bed can be increased, a large amount of microorganisms can be adhered to surely carry out the treatment, and it is not compacted and the pressure loss is small.

Further, since the raw water is made to flow upward to the packed bed through the water supporting the packed bed, the raw gas increases the water content and gives water to the microorganisms attached to the floating carrier forming the packed bed to enhance the activity. At the same time, the organic compound in the raw gas is dissolved in the water contained in the gas, and the microorganisms are easily oxidized and decomposed, so that the treatment efficiency is high.

[Brief description of drawings]

1 is a cross-sectional view of an embodiment of the gas biological treatment apparatus of the present invention.

[Explanation of symbols]

10 treatment tanks 11 water 12 Packed bed 13 Gas introduction pipe (gas introduction means) 14 Process gas discharge port (process gas discharge means) 15 Packed bed restraint plate 16 Sprinkler 17 Overflow port

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B01D 53/34 C02F 3/00

Claims (5)

(57) [Claims] 1. A treatment tank in which water is stored in the lower portion and a floating carrier to which microorganisms are adhered, and the floating carrier is a polystyrene foam.
Granules molded with foamed or closed-cell polyurethane foam
In the floating state in which the lower part of the packed layer composed of the floatable carrier is immersed in water in the treatment tank, and the packed layer above the immersed part is supported by buoyancy. A gas introducing means for introducing the raw gas into the water in the lower part of the processing tank, and a processing gas discharging means for discharging the processing gas outside the tank from above the packed bed in the processing tank. Gas biological treatment equipment. 2. The biological treatment apparatus for gas according to claim 1, wherein the depth of water in the treatment tank is 5 to 100 cm and the height of the packed bed is 0.3 to 5 m. Processing equipment. 3. The biological treatment apparatus for gas according to claim 1, wherein the buoyant carrier has a specific gravity of 0.01 to 0.2 and a particle size of 1 to 50 mm. A biological treatment apparatus for gas, which is characterized by being an object. 4. The biological treatment apparatus for gas according to claim 1, wherein a restraint plate is provided on the packed bed. apparatus. 5. A packed bed in which the raw gas is introduced into the water stored in the lower part of the treatment tank, and which is composed of a floating carrier to which microorganisms are adhered, the lower part of which is immersed in the water of the treatment tank in a floating state. The floating carrier is styrofoam.
Or, it is a granular material molded with closed-cell polyurethane foam.
And discharging the gas aerated to the packed bed from above the packed bed to the outside of the tank.