JPH09225253A - Method for deodorizing malodorous gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably deodorize malodorous oxygen at a high rate with high efficiency and to obtain a deodorizing method using a deodorization bed of an easily available inexpensive material easy to discard. SOLUTION: A moss-packed bed 4 is arranged in the vapor-phase part 6 of a deodorization tank 3, and water is sprinkled by a nozzle 5 from above the bed to deodorize malodorous gaseous oxygen 1. A suspended particle-contg. water 7 accumulated on the bottom of the tank 3 in contact with the bed 4 is returned above the bed and sprinkled. When the moisture in the malodorous gaseous oxygen is condensed in the system to by-produce water, the suspended particle-contg. liq. is subjected to solid-liq. separation, and the supernatant water is discharged outside the system only by the amt. corresponding to the by-product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for deodorizing odorous gas generated during storage and treatment of waste and waste water, food processing, livestock production, painting, casting and the like.

[0002]

2. Description of the Related Art In recent years, a biological deodorization method as an industrial deodorization method for odor-containing waste, in particular, a sprinkling type biological deodorization method that can deal with various odorous components and has a large treatment capacity even with low pressure loss has become mainstream. There is. In this method, a packed bed of a microorganism-adhering carrier is arranged in the gas phase of a deodorizing tank, and while contacting with an odorous gas while sprinkling water from the floor, the odorous components dissolved in water are decomposed by microorganisms to deodorize. ((1) JP-A-7-251027
, (2) Environmental Technology Vol. 24, No. 10, 608-61
P. 3, Kazuhiro Shinabe, "Application Example and Design Method of Filling Type Biological Deodorization System").

Conventionally, as a carrier, a carrier formed by molding an electro-resin or ceramic into a spherical shape or a short tubular shape has been used. Most of them are carriers with a diameter of several cm or more that are mass-produced as packings for reaction towers and absorption towers in the petrochemical industry. But,
The specific surface area is small, and the once adhering microbial layer is easily peeled off. In order to increase the specific surface area, attempts have been made to mold synthetic resin into fibers or use porous materials. However, there is a problem that the microbial cells that have proliferated and agglomerated easily fill the gaps and are clogged, and that the deteriorated packing contains the synthetic resin and the biological sludge and is difficult to be discarded. Furthermore, it is expensive because it is produced in small quantities with a deodorizing carrier.

[0004]

DISCLOSURE OF THE INVENTION The object of the present invention is to deodorize odorous oxygen-containing gas at a high speed with a high deodorizing rate and stably, and to deodorize with a material that is easily available, inexpensive and easy to dispose on a deodorizing floor. A method and apparatus therefor are provided.

[0005]

DISCLOSURE OF THE INVENTION In order to improve the drawbacks of the conventional sprinkler-type biological deodorizing method, the present inventors have examined the conditions of a carrier-packed bed having high treatment efficiency and high deodorizing rate and excellent stability. . As a result, they have found that the point is to use a carrier satisfying the following requirements under conditions suitable for the characteristics of the carrier. 1) Support the microbial layer thinly and uniformly. 2) Microorganisms easily grow. 3) Large specific surface area. 4) The adherent microbial layer is difficult to peel off from the carrier surface. When the layer is fertilized, the outer fertilized layer is removed, leaving a thin layer in contact with the inner surface of the carrier, and the thickness of the layer is kept constant. 5) The carrier is highly resistant to microbial degradation. 6) Easy to obtain and inexpensive. 6) Easy to dispose of when disposing.

As a result of extensive research on a carrier material satisfying the above conditions and a method and apparatus structure for deodorizing the carrier material, the inventors have found that water moss is suitable as a carrier and have reached the present invention.

As shown in FIG. 1, water moss has a large number of branch structures 23 branching from a trunk structure 22 and an innumerable scale-like structure 24 around both of them, which is inexpensive as a water retaining material for garden pots. Easily available at.

The odorous oxygen-containing gas that is the subject of the present invention is not particularly limited as long as it is a gas that cannot be decomposed by microorganisms and contains a toxic component. For example, it can be used for odorous gas generated in storage and composting of food waste, livestock production, storage and treatment of human sewage's human waste, agricultural and livestock marine product processing and waste wastewater treatment thereof, coating, casting using sand mold, and the like.

The first feature of the present invention is to use water moss as a carrier in a deodorizing method in which an odor-containing oxygen-containing gas is brought into contact with a microbial-adhesive carrier-packed bed arranged in a gas phase space in a sprinkling state. . The type and quality of the water moss are not particularly limited. The particle size varies depending on the structure for accommodating or supporting the water moss, but generally, the diameter may be 20 mm or more. Less than 20 mm is difficult to support.

The colonization of microorganisms can be achieved by continuously sprinkling water containing microorganisms, which is a source of microorganisms, on a bed of moss.
The microorganism source is not particularly limited. For example, suspended water of activated sludge used for treating organic wastewater or natural water of rivers and ponds can be used. Aeration conditions and watering conditions are the concentration of raw gas,
It depends on composition, air supply rate, target deodorization rate, temperature, etc., as well as bed density and structure. 9 of odor component under normal environment
To remove more than 5%, SV is 1000h under aeration conditions.
^{-1 or} less, superficial tower linear velocity (LV) within 0.5 m / s, 20 m ³ / m ³ / d under sprinkling conditions, liquid gas ratio of 0.3 L-water / m ³
-Practical deodorization is possible below raw gas.

The bed filled with water moss is arranged horizontally or vertically in layers in the gas phase portion of the deodorizing tank, and gas-liquid contact is made under sprinkling water. The ventilation direction is convection with the falling direction of the water spray, that is, an upward flow.
Watering can be continuous or intermittent. When arranging the floor horizontally, a mesh may be arranged at the bottom of the floor, or water moss may be stored and fixed in a plate-shaped casing made of the mesh.

A second feature of the present invention is that the water that has come into contact with the bed and flows down is separated into supernatant water and a suspension particle concentrate containing microbial flocs as the main component, and the suspension particles concentrate is separated from the top of the bed. It is to send it back to and water it. Odor-containing gas often contains water, such as gas generated from waste wastewater treatment, and in that case, the deodorizing system condenses the water, and water is by-produced by the amount corresponding to the drain. By-product water must be discharged to the outside of the system, but if it is discharged while containing microorganisms, the amount of microorganisms in the tank will decrease and the deodorizing performance will decrease. Therefore, the by-product water is settled and separated, and only the supernatant water is discharged out of the system. When the odorous gas is lower than the water content of the gas in the deodorization tower, the water in the system is lost together with the process gas, so that make-up water needs to be supplied. When the deodorized gas contains a large amount of mist, the deodorized gas is discharged to the outside of the system through the mist separator. The recovered water of mist origin can be returned to the system. On the other hand, the microbial cells increase with the absorption of volatile organic compounds as nutrient components of the odorous gas. However, when the load is low, the amount of microbial cells reduced by respiration exceeds the amount of microbial cells produced by growth, and the amount of microorganisms in the tank decreases.

When the amount of the suspended particle concentrated liquid exceeds the set amount, the surplus is withdrawn from the system. The amount of concentrated liquid can be monitored by detecting the difference in the amount of light transmission at the liquid-liquid interface with a light transmission sensor or the like. If the set amount is not reached, a limiting nutrient component is added. Since the organic components of the odorous gas are mainly volatile organic substances, a shortage of inorganic nutrient salts is likely to occur in the process of continuing operation for a long time. The nutritional component to be added is not particularly limited, but the amount is sufficient to maintain the microorganisms in the bed, and is usually one thousandth or less of the amount of organic matter in the contained gas. As nutrient components, those containing potassium, magnesium, calcium, and trace metal elements that tend to be deficient in addition to organic carbon, nitrogen, and sulfur, for example,
It may be organic waste water, compost, sludge digested material, or the like.

When water is sprinkled on the moss bed, microorganisms in the water form a thin film on the surface of the moss, and the flocs of the microorganisms are captured in the scale structure in good yield. Excessive amount of flocs flow down, so floor blockage is unlikely to occur. In addition, unlike the surface of synthetic resin and ceramics, the surface of water moss remains as a thin film without peeling off the entire thickened and thickened film, so the amount of microorganisms supported as a thin film per floor volume is several times greater. Correspondingly, the deodorization efficiency is improved accordingly.

In order to reduce the occurrence of distribution in the water flow and the gas flow in the floor to prevent a short circuit and improve the deodorizing rate, it is effective to stack the floors in a plurality of layers with a space layer sandwiched between them by a mesh or the like.
At that time, if the floor is housed in a mesh-shaped plate-like car body, it is easy to uniformly fill and the floor is easy to replace. It is also possible to arrange the floors vertically and to bring the watering and gas streams into contact with the floor. Especially, when it is desired to perform stable operation for a long period of time in a state where the scale is large and the pressure loss is small, the vertical arrangement is advantageous. Since gas-liquid contact efficiency is close in a single bed,
It is possible to form a curved flow path that is formed by partially partitioning the inside of the tank, and arrange the floors in the vertical direction in each of the partitioned sections. It is possible to devise a vertical floor by filling the casing with a mesh plate and partitioning the inside with water moss, and by providing multiple protrusions in the horizontal direction from the mesh so that the water moss does not fall.

Although water moss is a natural material, it has a resistance to microbial decomposition in water or in a wet condition, and has at least 2
The original physical properties can be maintained for 3 years. In addition, since it is a natural material when it is deteriorated and disposed of, it is easier to dispose of than conventional synthetic resins and ceramics.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

(Example 1) Fig. 2 shows a flow chart of deodorization by a deodorizing bed uniformly filled with water moss. The bed of water moss packed with microorganisms attached to the gas phase portion 6 of the deodorization tank 3 is supported in the gas phase portion 6 inside the tank by a support mesh 4-3. The suspended particle-containing liquid 7 obtained by filtering the water-moss-filled bed 4 stays at the bottom of the deodorizing tank 3, and is sprayed on the water-moss-filled bed 4 with a water spray nozzle 5 through a suspension particle-containing liquid return pipe 12 and a pump 13. , Odor-containing and oxygen-containing gas 1 with water moss packed bed 4
From the bottom of the. During the process of passing through the moss-packed bed 4, the odor component and oxygen of the odorous oxygen-containing gas 1 are dissolved in water and decomposed by microorganisms adhering to the moss to remove the odor. Since the deodorized gas contains mist, it is introduced into the mist separator 16 and the deodorized gas 2 from which mist has been separated and removed is discharged to the outside of the system through the pipe 15 and the blower 14. The mist origin drain 17 is returned to the deodorizing tank 3 via the pipe 18. On the other hand, on the right side of the bottom of the deodorization tank 3, there is a sedimentation separation tank 10 adjacent to the partition wall whose bottom communicates with each other, and the solid water is separated into the supernatant water 8 and the suspended particle concentrate 9. The water level controller 11-1 opens and closes the control valve 11-2 via the signal line 11-3 to the extent that the water level exceeds the set water level, and discharges it out of the system. When the makeup water 19 is required, the signal of the water level adjusting device 11-1 is opened and closed by the makeup water regulating valve 11-5 through the signal line 11-4, and the signal is sent to the bottom of the deodorizing tank 3 through the pipe 12. Supply the make-up water 19.

(Embodiment 2) The bed of water moss packed in Example 1 is 4
An example is shown in which the layers are divided into three layers of -a, 4-b, and 4-c, and the layers are laminated below the mesh 4-3 at the bottom of each floor with a space therebetween. By dividing and stacking the beds, the deodorization rate can be improved by suppressing the occurrence of the flow velocity distribution in the bed of the flowing sewage and the rising gas, as compared with the single-layer packed bed of Example 1.

FIG. 4 shows an embodiment of the structure of the divided floor 4. The water moss is divided into small sections by side walls 4-3 and partition walls 4-2, and is composed of two upper and lower surfaces 4-3 made of mesh. With this structure, it is possible to prevent water moss from moving due to the flow of water and to prevent uneven density in the bed.

(Embodiment 3) FIG. 5 shows a flow of a deodorizing device having a packed bed arranged in the vertical direction. In the gas phase part 6 of the deodorization tank 3, a bed of water moss packed with microorganisms is arranged vertically.
In the tank, a plurality of partition plates 20 and 21 partition the gas phase portion so as to be partially continuous to form a bent gas flow path. When the odorous oxygen-containing gas 1 is supplied to the bottom of the deodorizing tank 3, the gas 1 passes through the bent gas passage formed by the partition plates 20 and 21. In the process, the gas 1 is contacted with the water spray from the water spray nozzle 5 arranged at the upper part of the tank and the water moss packed bed 4 with microorganisms attached, and is discharged out of the tank through the pipe 22. The suspended particle-containing liquid 7 obtained by filtering the water moss packed bed 4 stays at the bottom of the deodorizing tank 3, and the suspended particle-containing liquid return pipe 12 and the pump 1
It returns to the bed 4 filled with water moss with the watering nozzle 5 through 3. Since the deodorized gas contains mist, the deodorized gas 2 is introduced into the mist separator 16 to separate and remove the mist.
Is discharged to the outside of the system through the pipe 15 and the blower 14. On the other hand, on the right side of the bottom of the deodorization tank 3, there is a sedimentation separation tank 10 adjacent to the partition wall whose bottom communicates with each other, and solid-liquid separation is performed into the supernatant water 8 and the suspended particle concentrate 9. Water level adjustment device 11-
By 1, the control valve 11-2 is opened / closed via the signal line 11-3 and discharged to the outside of the system by the amount exceeding the set water level. If make-up water 19 is required, the water level adjusting device 11-1
Supply signal via the signal line 11-4
-5 is opened and closed, and makeup water 19 is supplied to the bottom of the deodorizing tank 3 through the pipe 12.

FIG. 6 shows an embodiment of the vertical packed bed 4. The surrounding wall 4-1, the front and back surfaces 4-3, and the inner partition wall 4-2 are both made of a mesh to form a box body, and the front and back surfaces 4
A large number of protrusions 4-4 are provided in the lateral direction from -3. By filling this with water moss, the water moss is supported by the protrusions, and thus it is possible to prevent the water moss bed from settling down and lowering the contact efficiency.

[0022]

【The invention's effect】

1) Unlike conventional synthetic resin or ceramic carriers, the bed composed of the water moss according to the present invention can support a large amount of bacteria as a thin film layer effective for deodorization, and therefore can quickly carry out odorous gas at a high deodorization rate. Can be deodorized.

2) Despite the fact that the floor made of water moss according to the present invention is a natural material, it has excellent durability and is easily available. In addition, it is easy to discard the used carrier when exchanging.

3) The bed is not clogged due to the self-cleaning action of leaving a thin layer of microorganisms on the surface of the water moss and the thickened layer falls off, and the effective amount of microorganisms carried on the bed can be adjusted to the maximum. The deodorizing performance can be stably maintained for a long time.

4) With the floor structure of the present invention, it is possible to prevent a short circuit of raw gas and maintain a stable high deodorizing rate.

5) The vertical floor is easy to replace and the unit tanks are connected in series to facilitate the expansion.

[Brief description of drawings]

FIG. 1 is an explanatory view of the structure of water moss.

FIG. 2 is a system diagram of the deodorizing device according to the first embodiment of the present invention.

FIG. 3 is a system diagram of a deodorizing device according to a second embodiment of the present invention.

FIG. 4 is an explanatory view of a bed of water moss used in the deodorizing apparatus of Example 2 of the present invention.

FIG. 5 is a system diagram of a deodorizing device according to a third embodiment of the present invention.

FIG. 6 is an explanatory diagram of a bed of water moss used in the deodorizing apparatus of Example 3 of the present invention.

[Explanation of symbols]

1 ... Odor-containing oxygen-containing gas, 2 ... Deodorization treatment gas, 3 ... Deodorization tank,
4 ... Water moss packed bed, 5 ... Sprinkling nozzle, 6 ... Gas phase part, 7 ... Suspended particle-containing liquid, 8 ... Supernatant water, 9 ... Suspended particle concentrated liquid, 10
… Sedimentation / separation tank, 11… Water level control device.

 ────────────────────────────────────────────────── ─── Continued on front page (72) Inventor Takeshi Takemoto 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd.

Claims (8)

[Claims] 1. A odor-containing oxygen-containing gas characterized in that moss is used as a carrier in a deodorizing method in which a odor-containing oxygen-containing gas is brought into contact with a microbial-adhesive carrier-packed bed arranged in a gas phase space in a sprinkling state. Deodorizing method. 2. The method according to claim 1, wherein water flowing in contact with the bed is separated into supernatant water and a suspension particle concentrate, and the suspension particle concentrate is returned to the upper part of the bed for water spraying. Odor-containing oxygen gas deodorizing method. 3. The odor-containing oxygen-containing gas according to claim 2, wherein the surplus water is discharged to the outside of the system when the surplus water is by-produced excessively, and supplemental water is supplied from the outside of the system when the supernatant water is insufficient. Deodorizing method. 4. The odorous oxygen-containing oxygen supply system according to claim 2 or 3, wherein when the amount of the suspended particle concentrated liquid exceeds the set amount, the surplus is taken out of the system, and when it decreases, the nutrient source is replenished. How to deodorize gas. 5. The deodorizing device for odorous and oxygen-containing gas according to claim 1, 2, 3, or 4, which has a tank structure in which a plurality of unit layers supported by a horizontal porous support structure are laminated. 6. The deodorizing device for odorous, oxygen-containing gas according to claim 5, which has a space between upper and lower layers. 7. The deodorizing device according to claim 1, 2, 3 or 4, wherein the floor has a vertical plate shape. 8. The curved path in which the gas phase portion is continuous by alternately arranging a plurality of parallel vertical partition plates in the gas phase portion between the deodorizing tank and the bottom water surface of the tank according to claim 7. The above-mentioned floor is arranged vertically in each compartment of the gas phase part formed between the partition plates, and the odorous oxygen-containing gas is supplied from the upstream of the curved path and the deodorized gas is discharged from the most downstream part to the outside of the tank. Method for deodorizing odorous oxygen-containing gas.