JPH07251027A - Management method of biological deodorizer - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method for controlling a biological deodorizing device, which can satisfactorily regenerate the deodorizing ability of the device in a short period when restarting from a stopped state. In a method of controlling a biological deodorizing device, a gas 1 containing a malodorous component is brought into contact with a packed bed 3 to which microorganisms that decompose the malodorous component and deodorize (hereinafter referred to as “deodorizing organisms”) are attached to deodorize the device. When stopping, the deodorized organisms retained in the packed bed 3 are dried to maintain the dry state during suspension,
At the time of use, the deodorizing ability is activated by replenishing water 9, and the deodorizing organisms are dried by passing a drying gas through a packed bed, or even when the inside of the apparatus is in a negative pressure state. Often, the water content is 30% or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a biological deodorizing device, and more particularly, to a malodorous component such as fatty acid, ammonia, hydrogen sulfide and methyl mercaptan generated in human waste treatment plants, sewage treatment plants and chemical plants. The present invention relates to a method for managing a biological deodorizing device that deodorizes a malodorous gas including.

[0002]

2. Description of the Related Art Biological deodorizers are widely used as low-cost deodorizers for malodorous gases generated in human waste treatment plants, sewage treatment plants, chemical plants and the like. The principle of the biological deodorizer is as follows. That is, the malodorous gas is passed through the packed bed filled with the carrier, and the malodorous components are decomposed by the organisms attached to the carrier. It also replenishes the organisms with water by watering the packed bed and at the same time removes waste products from the packed bed. At this time, the malodorous component is an energy source or a carbon source for the deodorizing organism. Then, the deodorizing organism proliferates by decomposing the malodorous component. The deodorized organisms that have proliferated die by autolysis and predation, and the amount of deodorized organisms in the packed bed is in a dynamic equilibrium state depending on the amount of malodorous component supplied.

By the way, the odor concentration of the malodorous gas varies depending on the climate change and the operating condition of the factory, and the treatment capacity of the biological deodorizer also varies accordingly. Therefore, when the odor is not generated, the deodorizing organism does not grow and only kills. If this state continues for a long period of time, the deodorizing organisms in the packed bed will decrease, and in some cases almost all will die. In such a condition, when the bad odor re-occurs, the deodorizing ability is lost, and when restarting, recovery is possible even if measures such as inoculating surplus sludge from the activated sludge treatment facility for sewage and wastewater are taken. It takes a few weeks to a month or more.

On the other hand, as a method for producing the so-called immobilized microorganism as described above, Japanese Patent Application Laid-Open No. 64-2569 discloses a method of self-particle formation by low-temperature drying. It is generally known to have resistance to dryness. Further, as an application of the above technique to deodorization, JP-A-5-123527 describes a method of using a dried product of excess sludge as an immobilized microorganism (deodorant). In this method, the dried product of the surplus sludge has both the functions of the biological carrier and the seed sludge, and can be deodorized without adding the surplus sludge (in the form of suspension) at the start of the operation.

Since the above-described technique uses the deodorized microbial particles once produced in an aeration tank or a deodorization tower, the working environment of the deodorant-immobilized microorganisms is not much different from that of the conventional deodorizing device, and the odor in the water of the deodorizing device does not change. It is easily inferred that the deodorizing ability will be lost when it is not supplied for a long period of time. Further, in this embodiment of the method, space velocity (SV)
Although a which was about 4hr ^-1, recently, deodorizing apparatus which is used in sewage treatment plants is about SV = 70~750hr ^-1, this method has not been practical.

[0006]

DISCLOSURE OF THE INVENTION The present invention maintains a deodorant organism even when the supply of malodorous components is stopped, does not require a procedure such as addition of inoculum at the time of restarting, and can satisfactorily improve the device in a short time. An object of the present invention is to provide a management method of a biological deodorizing device capable of reproducing the deodorizing ability.

[0007]

In order to solve the above problems, in the present invention, a gas containing a malodorous component is brought into contact with a packed bed on which microorganisms (deodorant organisms) that decompose and deodorize malodorous components are attached. In the management method of the biological deodorizing device for deodorizing,
When the apparatus is stopped, the deodorizing organisms retained in the packed bed are dried to maintain the dry state during the stop, and when used, water is replenished to activate the deodorizing ability.

In the above management method, the deodorizing organisms retained in the packed bed are dried by heating the drying gas with a heater or dehumidifying with a dehumidifier when the temperature of the drying gas such as the atmosphere is high. It is only necessary to reduce the humidity and then to contact with the packed bed, and at this time, it is preferable that the inside of the apparatus is in a negative pressure state. Further, as a deodorizing device for carrying out the above method, a packed bed to which microorganisms decomposing malodorous components are attached, a nozzle for sprinkling circulating water on the upper part of the packed layer, a water tank for receiving circulating water on the lower part, and a treatment A device equipped with a blower for sending gas to the packed bed can be used, and the device may be provided with a heater or a dehumidifier for reducing the humidity of the drying gas, and the device is kept in a negative pressure state. You may provide the vacuum pump for this.

[0009]

The present invention is based on the concept of low temperature dry preservation known as a method for preserving microbial strains, as described in "PPM" March 1992.
In addition to the activated sludge organisms disclosed in the monthly issues p22-28 and the above publications, etc., it is applied to the preservation and regeneration of specialized deodorant organism groups in an open-type large-scale deodorizing device, and the ability to preserve the deodorant organisms I got a special effect on the reproduction. That is, the present invention, when stopping the biological deodorizing device, stop the water supplied to the packed bed of deodorizing microorganisms, after draining the water in the device, or aeration of low humidity air to the packed bed, Alternatively, it is a method for maintaining the decomposing ability, which is characterized in that the deodorizing organism retained in the packed bed is dried by making the whole device into negative pressure.

The present invention will be described in detail below with reference to the drawings showing an example of the present invention. FIG. 1 is a schematic explanatory diagram of the biological deodorizing device during operation, and FIGS. 2 and 3 are schematic explanatory diagrams of the biological deodorizing device during drying. As shown in Figure 1, during operation,
The malodorous gas 1 is passed through the packed bed 3 using the blower 2 and the processing gas 4 is discharged from the exhaust port 5. In addition, the circulating water 6 is filled with the packed bed 3
Water is sprayed from the upper nozzle 7 and collected in a water tank 8 provided below the packed bed 1.

A method of passing low-humidity air through the packed bed to dry the deodorized organism will be described with reference to FIG. When stopping the apparatus, first, ventilation and water sprinkling are stopped, and water in the apparatus is discharged from the drain port 10. Subsequently, the air 12 is heated by the heater 11 and then passed through the packed bed 3, and the exhaust gas 13 is discharged from the exhaust port 5 in the upper part of the apparatus. As a result, the deodorized products in the packed bed are dried. Drying is preferably carried out at the lowest temperature possible and in a short time.
Cold air requires a very long time when used to dry deodorant organisms because of its low saturated water vapor concentration.

However, it is possible to raise the saturated steam concentration by slightly heating low-temperature air. For example, air with a temperature of 10 ° C has a saturated steam concentration of 0.008 m.
g- steam / m ³ - is a dry air, at a temperature 30 ° C. The air 0.027mg- steam / m ³ - a dry air. That is, even if air having a temperature of 10 ° C. and a relative humidity of 100% is heated to 30 ° C., 0.02 mg-steam / m ³ -steam of dry air can be newly retained. However, if the temperature is raised too high, there is a risk that the deodorizing enzyme possessed by the organism will be denatured and its function will be lost.

Therefore, the drying temperature is determined according to the temperature tolerance of the target microorganism. For example, the activity of methane-oxidizing bacteria having excellent heat resistance can be maintained even at a high treatment temperature, but in this case as well, it is desirable that the temperature is about 70 ° C or lower. When treating aerobic microorganisms such as activated sludge, the temperature is preferably about 50 ° C or lower. In many cases, it is practically impossible to identify microorganisms, and therefore it is preferable to elevate the temperature to a temperature that is usually allowed during deodorization operation. Therefore, if the temperature rises due to the heat generated by the blower or if the odorous gas has a high concentration and high temperature, the discharge temperature of the heat exchanger for cooling can be used as a guide after the natural drying temperature for a short time.

A method of drying the deodorized organisms by setting the inside of the apparatus to a negative pressure will be described with reference to FIG. Similar to the above, first, the ventilation and water sprinkling of the apparatus are stopped and the water in the apparatus is discharged. Then, a vacuum pump 14 is connected to the exhaust port 5, all other openings are sealed, the vacuum pump is operated to make the inside of the device a negative pressure, and the water inside the device is volatilized and removed. In any of the methods, after the drying is completed, the deodorizing device, especially the packing layer, is closed. At that time, in order to maintain the dry state, it is preferable to put a desiccant in the deodorizing device. The target of drying is to set the water content to 30% or less, preferably 25% or less.
When the water content is higher than this, self-decomposition of microorganisms causes a rapid decrease in deodorizing ability as in the conventional case, making regeneration impossible.

[0015]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples. Example 1 As a result of operating the biological deodorizer for 3 months under the following conditions,
As shown in Table 1, various malodorous components were well removed. The filler of this biological deodorizer was taken out, and the sulfur-oxidizing bacteria adhering to the filler were counted.

(Treatment conditions) Superficial velocity: 0.7 m / sec Water spray rate (per unit treatment time): 3 liters / m ³ Gas temperature: 20-25 ° C. Filler: Special sponge Cross section of packed bed: 0.2 m ² Packed bed height: 1 m Initial MLSS: 2000 ppm pH of circulating fluid: 6 to 8 (adjusted with NaOH)

[0017]

[Table 1]

Further, the filler of the same biological deodorizing device was put in a drier and the temperature was kept at 40 ° C. to dry the filler. The drying time was changed stepwise to obtain a filler having a water content of about 10 to 70%. Put these fillings in a closed container 28
It was left at ℃. After 2 months, the number of sulfur-oxidizing bacteria was measured according to the method described above, and the relationship between the water content of the filler and the number of sulfur-oxidizing bacteria after long-term storage was clarified. The above results are shown in FIG.
Shown in. When the water content was 25% or less, the number of sulfur-oxidizing bacteria was in the range of about 1/15 to 1/5 of that before storage and was well preserved. However, when the water content exceeded 30%, the number of bacteria decreased sharply. From the above results, it was clarified that the sulfur-oxidizing bacteria can be stored for a long period of time by setting the water content of the filler to which the deodorizing organism is attached to about 30% or less.

Example 2 Three biological deodorizers, device 1, device 2 and device 3 were operated for 3 months under the treatment conditions shown below. The malodorous gas was artificially adjusted. As a result, as shown in Table 2, the inflowing malodorous substances were decomposed with high efficiency in any of the devices. (Treatment conditions) Superficial velocity: 0.7 m / sec Sprinkling amount (per unit treatment time): 3 liter / m ³ Gas temperature: 20 to 25 ° C. Filler: Special sponge Filled layer cross-sectional area: 0.2 m ² Filling Layer height: 1 m Initial MLSS: 2000 ppm pH of circulating fluid: 6-8 (adjusted with NaOH)

[0020]

[Table 2]

Subsequently, ventilation and water sprinkling of each device were stopped. And after the circulating water is discharged from the device 1 and the device 2,
The deodorized product was dried under the following conditions. The device 1 was dried by passing a reduced-humidity atmosphere through a packed bed. The device 2 was dried by setting the inside of the device to a negative pressure state. After that, the device 1 and the device 2 were sealed and left to stand. In addition, the device 3 stopped the ventilation and water sprinkling and was left as it was.

(Drying conditions of apparatus 1) Superficial velocity: 0.7 m / sec Inflowing gas temperature: 40 ° C. Inflowing gas relative humidity: 10-40% Drying time: 4 days (Drying conditions of apparatus 2) Degree of vacuum: Approximately 70 Torr or less Drying temperature: 8 to 17 ° C. Drying time: 4 days Before standing, the water content of the deodorizing organisms in each device was measured. The results are shown in Table 3.

[0023]

[Table 3]

After the lapse of 2 months, circulating water was injected into the devices 1 and 2, watering was restarted, and then the above three devices were operated under the initial operating conditions. Table 4 shows the treatment results after 5 days of operation. The processing results of the devices 1 and 2 were similar to the processing results before drying. On the other hand, in the device 3, all the three types of malodorous substances remained in the treated gas at a considerably high rate. This is because most of the deodorant organisms were preserved by drying in the devices 1 and 2,
The deodorizing ability is maintained, and the device 3 shows that the deodorizing ability is lost as a result of the death of most of the deodorizing organisms.

[0025]

[Table 4]

[0026]

According to the present invention, the deodorizing ability can be restored in an extremely short period of time even after the deodorizing device has been stopped for a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram of a biological deodorizing device during operation.

FIG. 2 is a schematic explanatory view of a biological deodorizing apparatus when drying a deodorizing organism by passing low humidity air through a packed bed.

FIG. 3 is a schematic explanatory view of a biological deodorizing device when drying a deodorizing component by setting a negative pressure inside the device.

FIG. 4 is a graph showing the relationship between the dry state of the filler and the long-term storage state of sulfur-oxidizing bacteria.

[Explanation of symbols]

1: Malodorous gas, 2: Blower, 3: Packed bed, 4: Process gas, 5: Exhaust port, 6: Circulating water, 7: Nozzle, 8: Water tank,
9: Supply water, 10: Drainage port, 11: Heater, 12: Air, 13: Exhaust gas, 14: Vacuum pump

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location A61L 9/01 P B01D 53/34 ZAB (72) Inventor Masami Kitagawa 4-chome, Fujisawa, Fujisawa-shi, Kanagawa No. 2 No. 1 EBARA Research Institute

Claims (1)

[Claims] 1. A method for controlling a biological deodorizing device, which comprises deodorizing a gas containing a malodorous component by contacting it with a packed bed on which a microorganism that decomposes the malodorous component and deodorizes it (hereinafter referred to as "deodorizing organism") is used. When stopping, the deodorizing organisms retained in the packed bed are dried, the dry state is maintained during suspension, and at the time of use, the deodorizing ability is activated by replenishing water to control the biological deodorizing device. .