JP2000176238A - Acclimatizing method of biologically deodorizing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise the ammonia load syncronizingly with an acclimatizing stage and to smoothly advance the proliferation of nitrifying bacterium by introducing gaseous ammonia in a suitable amount in accordance with the acclimatizing stage during the acclimatizing term of a carrier packed biologically deodorizing device for deodorizing ammonia. SOLUTION: The waste gas sent from a waste gas supply pipe 2 to a biologically deodorizing column 1 is discharged from a discharge pipe 6 while passing through a packed layer 3 and while transferring the ammonia to treating water to decompose. In such a case, in the case where the acclimatization in which the amount of the nitrifying bacterium is gradually increased just after depositing sewage sludge, etc., on the packed layer 3 is executed, the raw gas for acclimatization regulated to a prescribed concn. by diluting the waste gas or commercially available gaseous ammonia with the air is introduced. Then the treating water 41 is sprinkled to the packed layer 3 from a sprinkling line 4 to dissolve the ammonia in the treating water 41. Thereafter, the ammonia concn. in the raw gas for the acclimatization is regulated to maintain the amount of the nitrifying bacterium in constant while measuring the pH value of the drain stored in a water storage tank 5 with a pH meter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for acclimating a biological deodorizing apparatus for deodorizing ammonia.

[0002]

2. Description of the Related Art A carrier-filled type biological deodorizer is used to fill a treatment tower (deodorization tower) with a filler (abbreviation: carrier) in which microorganisms are maintained at a high density, and use the action of the microorganisms to carry out malodorous substances. Is to be decomposed. The malodorous substance is dissolved or absorbed in the moisture attached to the surface of the carrier when passing through the carrier. The malodorous substances trapped around the carrier are decomposed and deodorized by microorganisms that grow using the malodorous substances as a nutrient source. On the other hand, since a mixed microbial system such as sewage sludge is used as the inoculum of the microorganisms carried on the carrier, the deodorant is decomposed for a while after the deodorization device is started immediately after the inoculation of the inoculum. Since the microorganism to be grown is not sufficiently grown, a period is required until the intended resolution is exhibited, and this period is referred to as a habituation period.
In other words, microorganisms that decompose malodorous substances and serve as energy sources accumulate, and acclimatization is completed when they become dominant species in the mixed microorganism system. In general, technologies for treating sulfur odors such as hydrogen sulfide and methyl mercaptan in sewage treatment plants and the like using a carrier-filled biological deodorizing device have become widespread and are well-established technologies ("Carrier-based biological deodorizing systems"). Technical Manual ”, Sewerage New Technology Promotion Organization, 1
996, p. 41). The sulfur-based odor is deodorized by being oxidatively decomposed by the action of a sulfur-oxidizing bacterium. The acclimatization of the carrier-filled biological deodorizer for the purpose of deodorizing sulfur-based odors is very simple, and is carried out simply by continuously sending odor gas at a predetermined air volume. Although the sulfur-based odor of the raw gas is detected in the processing gas at the outlet of the tower, sulfur-oxidizing bacteria grow in the carrier with the passage of time, and as a result, the odor removal rate by the packed tower is improved. However, there have been few reports on the removal of odors containing high concentrations of ammonia generated in composting facilities for organic waste and the like, which has recently become a problem. Regarding the operation control method, there are some reports that an acid is added to the circulating water to suppress the pH value of the circulating water to 7.5 or less and to control the ammonia nitrogen concentration in the circulating water to 1000 mg-N / l or less. (JP-A-7-24247). Ammonia is generally deodorized by being oxidatively decomposed by the action of two types of bacteria, ammonia oxidizing bacteria and nitrite oxidizing bacteria. These oxidative decompositions are called nitrification reactions. First, ammonia is oxidized by the action of ammonia-oxidizing bacteria to produce nitrite, and nitrite-oxidizing bacteria oxidize nitrite to produce nitric acid. These bacteria are collectively called nitrifying bacteria.

[0003]

The nitrifying bacteria are very delicate bacteria, and it is necessary to precisely control a delicate growth environment in order to proliferate and sufficiently exhibit the nitrification reaction ability. Special attention is required for acclimation. The ammonia gas is absorbed by the water on the surface of the carrier and the pH around the carrier is
However, when the pH exceeds 8.5, the growth of nitrifying bacteria begins to be inhibited, and when the pH exceeds 9, the bacteria hardly grow, and the adaptation of ammonia as a biological deodorization tower becomes very slow. Therefore, an object of the present invention is to provide a means for promoting the growth of nitrifying bacteria by increasing the ammonia load in synchronization with the acclimatization stage so as not to cause such a state.

[0004]

According to the present invention, an appropriate amount of ammonia gas according to the acclimatization stage is supplied during the acclimatization period of a carrier-filled biological deodorization apparatus for deodorizing ammonia. The problem can be solved by the above-mentioned method for acclimating a carrier-filled biological deodorization apparatus, which is characterized by introducing. Further, the present invention also provides a method for increasing or decreasing the amount of ammonia gas in the acclimatizing gas so that water is sprayed on the packed bed carrying microorganisms in the deodorization tower and the drainage of the drain after passing through the packed bed is reduced.
The present invention also relates to a method for acclimatizing a carrier-filled biological deodorizing device, characterized in that the H value is maintained in the range of 6.5 to 8.5.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In general, a biological deodorizing apparatus for deodorizing ammonia odor has a treatment tower (deodorization tower) for ammonia-containing exhaust gas, a supply pipe for sending exhaust gas to be treated to the deodorization tower, a deodorizing tower, The system includes a discharge pipe for discharging the treated gas from the deodorization tower after the treatment, and a means for sprinkling water on the packed bed in the deodorization tower, and further includes, in some cases, a water reservoir for collecting recovered water after passing through the packed bed. In the biological deodorizing apparatus, ammonia-decomposing microorganisms (for example, nitrifying bacteria) are supported on the carrier of the packed bed in the deodorizing tower, and are carried in the deodorizing tower (in particular, when passing through the packed bed). Ammonia transferred from the exhaust gas into the sprinkling water is nitrified in the packed bed.

Immediately after the ammonia-degrading microorganisms are carried on the packed bed in the deodorization tower of such a biological deodorization device, the amount of the microorganisms is insufficient, so that acclimation is required.
In this case, by the method of the present invention, the growth of nitrifying bacteria during the acclimation period is not inhibited by controlling the ammonia inflow load so that the pH of the drain (recovered water) after passing through the packed bed does not exceed 8.5. Smooth habituation can be performed.
As a result of nitrifying bacteria growing by oxidative decomposition of ammonia, nitrous acid and nitric acid are generated, and the pH value of the drain (recovered water) becomes 6.
When the ammonia inflow load is increased when the pressure drops to 5, the pH increases again due to the dissolution of ammonia.
If the pH is 8.5 or less, the growth of nitrifying bacteria proceeds, and the pH value decreases again. Through these processes, the growth of nitrifying bacteria progresses, and the ammonia treatment capacity increases. By using the method of the present invention in which the ammonia inflow load is increased stepwise in this way, the habituation is performed more quickly than immediately after the start-up and a normal load is applied, and the predetermined performance is achieved quickly and efficiently. be able to. A typical embodiment of a biological deodorizing apparatus suitable for applying the method of the present invention is schematically shown in FIG. As shown in FIG. 1, an exhaust gas containing ammonia is introduced into a biological deodorization tower 1 from an exhaust gas supply pipe 2. The biological deodorization tower 1 is provided with a packed bed 3 filled with a carrier, a water sprinkling line 4 for pouring treated water 41 into the packed bed 3, a water sprinkling pump 42, and the like. For watering, fresh water (for example, tap water or industrial water) or a water storage unit 5 described later is used.
Returned water (circulating water) from is used as treated water. As the packed layer, a material and a shape that can efficiently transfer ammonia from the exhaust gas to the treated water when the exhaust gas passes through the packed layer and that can support microorganisms are used. You. Preferred fillers include, for example, soil, compost, beet, wood-based materials, ceramic-based materials, coal-based materials, synthetic resin-based materials, fibrous materials, or liquid materials, and insoluble fillers. More preferably used. For example,
What is described as a "carrier" in the "Technical Manual for Biodeodorization System Using Carriers" issued by the Sewerage New Technology Promotion Organization and its "Documents" (both issued in 1996) are used.

In the above-mentioned packed bed, ammonia-degrading microorganisms such as nitrifying bacteria (for example, ammonia-oxidizing bacteria and nitrite-oxidizing bacteria) are carried. In addition to the above-mentioned ammonia-decomposing microorganisms, microorganisms capable of decomposing malodorous substances generally contained in exhaust gas can be carried. By fixing such microorganisms in the packed bed, malodorous substances other than ammonia can be simultaneously treated. When simultaneously treating ammonia and a plurality of other types of malodorous substances, a plurality of types of microorganisms are used in accordance with the respective malodorous substances. Generally, the source of the exhaust gas to be treated contains microorganisms that decompose malodorous substances contained in the exhaust gas. Therefore, for example, when deodorizing the exhaust gas from sewage sludge, the substance to be treated can be inoculated by directly supporting the sewage sludge on the carrier.

[0008] The treated water sprinkled on the packed bed 3
After passing through, the water is collected and stored in the water storage tank 5. The recovered water (drain) in the water storage tank 5 may be drained or recycled as it is. When the water is circulated, the water in the water storage tank 5 is again poured into the packed bed 3 by the watering line 4 and the watering pump 42. In the method of the present invention, the pH of the recovered water (drain)
Since the value is measured, a pH meter 7 is provided in the water tank 5.
This water storage tank 5 can be formed at the bottom of the packed tower type biological deodorization tower 1 as shown in FIG. 1, but it is provided separately from the packed tower type biological deodorization tower 1, and the packed tower type biological deodorization tower 1 is connected via a pipe. Deodorization tower 1
Can also be connected.

When the recovered water in the water storage tank 5 is circulated and used, a carrier for supporting microorganisms can be inserted into the recovered water (drain) in the water storage tank 5 to carry ammonia decomposability on the carrier.

The exhaust gas sent from the exhaust gas supply pipe 2 to the inside of the biological deodorization tower 1 decomposes while passing through the inside of the packed bed 3 while transferring ammonia into the treated water, and further decomposes other odors in some cases. After being decomposed by the substance, it is deodorized and discharged from the exhaust pipe 6. The flow direction of the exhaust gas in the biological deodorization tower 1 may be an upward flow or a downward flow, but when the liquid material is used as the filler, the upward flow is used. Although the processing gas can be directly discharged to the outside air from the exhaust pipe 6, another processing apparatus, for example, an activated carbon adsorption tower or another type of adsorption or chemical deodorization apparatus is provided downstream of the biological deodorization tower 1. Can be placed and connected to them.

Immediately after sewage sludge or the like is carried on the packed bed 3 in the deodorization tower 1 of such a biological deodorization apparatus, the amount of nitrifying bacteria therein is insufficient. It is necessary to acclimatize. When the acclimatization step is performed, the exhaust gas to be actually treated or a commercially available ammonia gas is diluted with air into a biological deodorization tower 1 shown in FIG. Introduce gas. The ammonia gas concentration in the acclimatization raw gas is
The concentration is set to be much lower than the expected average concentration of ammonia gas in the exhaust gas to be actually treated. When treated water 41 is sprinkled from the sprinkling line 4 to the packed bed 3 while introducing the raw gas for acclimation, ammonia is dissolved in the treated water, and the pH value of the drain collected from the packed bed 3 and stored in the water storage tank 5 is collected. Is measured by the pH meter 7, the pH value becomes high. However, if the pH value is lower than 8.5, the nitrifying bacteria proliferate. Since the pH value of the drain gradually decreases with the growth of nitrifying bacteria, if the ammonia concentration in the acclimatizing raw gas is further increased, the pH value of the drain becomes a high value again, and then gradually decreases. It becomes repetition.
Through such repetition, the amount of nitrifying bacteria reaches a desired level, and the acclimatization process ends.

[0012]

EXAMPLES The present invention will be described below in more detail with reference to examples, but these examples do not limit the scope of the present invention.

EXAMPLE 1 Using a biological deodorizing apparatus of the type shown in FIG. 1, a habituation step according to the method of the present invention was carried out. In the acclimatization process started after applying the sewage sludge to the packed bed 3, the water storage tank 5
5. The drain pH measured by the pH meter 7 provided in the inside is 6.
The concentration of ammonia in the raw gas supplied from the raw gas supply pipe 2 was adjusted to be between 5 and 8.5. In FIG.
The ammonia concentration in the raw gas (● in FIG. 2), the ammonia concentration in the processing gas at the outlet of the deodorization tower 1 (the inlet of the exhaust pipe 6) (■ in FIG. 2), and the pH value of the drain (△ in FIG. 2) ). As is clear from FIG. 2, the ammonia concentration in the raw gas was to be increased stepwise. When the ammonia concentration in the raw gas is increased, the pH value of the drain becomes higher and then gradually decreases. Therefore, when the ammonia concentration in the raw gas is further increased, the pH value of the drain is increased.
The value was again high, and then decreased gradually. During this acclimatization process, ammonia was hardly detected in the processing gas, and after 2 months, the gas was acclimated as a deodorization tower capable of processing 200 ppm ammonia gas at a space velocity of 200 / hr. The drain pH value at this time became constant around 7, and thereafter showed no tendency to decrease. In Example 1 described above, the load was increased or decreased by adjusting the ammonia concentration in the raw gas. However, the same result was obtained even when the ammonia load was changed by changing the supply gas amount without changing the ammonia concentration. Can be obtained.

[0013]

Comparative Example 1 As in Example 1, a comparative acclimatization process was performed using a biological deodorizing apparatus of the type shown in FIG. In Comparative Example 1, in the acclimatization process that is started after applying sewage sludge to the packed bed 3, the space velocity 200
At 200 g / hr, the raw gas of 200 ppm of ammonia was kept flowing. Other conditions are the same as those in the first embodiment. FIG.
In addition, the ammonia concentration in the raw gas (● in Fig. 3), the deodorization tower 1
2 shows the change over time in the ammonia concentration (処理 in FIG. 3) in the processing gas and the pH value of the drain (△ in FIG. 3) at the outlet (the inlet of the exhaust pipe 6). As is apparent from FIG.
The above was maintained for 4 weeks or more, and after the first week, a large amount of ammonia was detected in the processing gas from the outlet, and the value gradually increased and then slightly decreased. However, even after two months, the processing gas contained 160 ppm of ammonia.
It was detected above.

[0014]

According to the present invention, the acclimatization period of the carrier-filled biological deodorization apparatus for deodorizing ammonia odor can be shortened and the efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a configuration of a biological deodorizing apparatus suitable for carrying out the method of the present invention.

FIG. 2 is a graph showing the effects of the acclimatization method according to the present invention performed in Example 1.

FIG. 3 is a graph showing the effect of the comparative acclimatization method performed in Comparative Example 1.

[Explanation of symbols]

1 ... packed-cell type biological deodorization tower; 2 ... raw gas for acclimation
Exhaust gas supply pipe; 3 ... packed bed; 4 ... water sprinkling line;
41 ... treated water; 42 ... pump; 5 ... water storage section; 6 ... treated gas discharge pipe; 7 ... pH meter.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C12S 13/00 F term (Reference) 4B029 AA02 AA21 BB01 BB02 CC02 CC10 CC11 CC13 DA06 DB19 DF02 DF04 DF06 DF10 4B033 NA02 NA11 NA12 NB62 NB65 NB67 ND04 ND10 ND20 NE02 NF04 NF06 4D002 AA13 AB02 AC10 BA02 BA17 CA01 CA07 DA58 DA59 DA70 GA01 GA02 GA03 GB01 GB02 GB09 HA10

Claims (2)

[Claims] 1. During the acclimatization period of a carrier-filled biological deodorization device for deodorizing ammonia, an appropriate amount of ammonia gas according to the acclimation stage is introduced.
A method of acclimatizing the above-described carrier-filled biological deodorization apparatus. 2. By increasing or decreasing the amount of ammonia gas in the acclimatizing gas, the pH value of the drain after being sprayed on the packed bed carrying microorganisms in the deodorization tower and passing through the packed bed is adjusted to 6.
A method for acclimatizing a carrier-filled biological deodorizing device, characterized in that the device is maintained in a range of 5 to 8.5.