KR101133548B1 - Apparatus and method for removing hydrogen sulfide odor using micro bubble ozone - Google Patents

Abstract

The present invention uses ultra-micro-foam ozone to prevent the generation of hydrogen sulfide-based odors including hydrogen sulfide and methyl mercaptan by directly incorporating ultra-fine-foam ozone into sewage, wastewater, sewage and sludge during the treatment of wastewater. It relates to a hydrogen sulfide-based odor removing device and method.
The odor of hydrogen sulfide or methyl mercaptans generated in the process of concentrating and dewatering sludge in wastewater or sewage treatment process is destroyed in the sludge using fine ozone bubbles, which can fundamentally block the generation of odors. There is an advantage that can be deodorized at a low installation cost.

Description

Hydrogen sulfide-based odor removal device and method using ultra-fine foam ozone {APPARATUS AND METHOD FOR REMOVING HYDROGEN SULFIDE ODOR USING MICRO BUBBLE OZONE}

The present invention relates to an apparatus and method for removing hydrogen sulfide-based odor using ultra-fine foam ozone. Specifically, ozone is directly mixed with sewage, wastewater, sewage and sludge in the process of treating wastewater, and includes hydrogen sulfide and methyl mercaptan. The present invention relates to a hydrogen sulfide-based odor removing apparatus and method using ultra-fine foam ozone to prevent the generation of hydrogen sulfide-based odors.

With urbanization and industrialization, various kinds of smells are generated around us. Individual tastes for odors are different, and the degree of detection according to the concentration also varies from person to person, but in most cases, an odor that is unpleasant in life is generally called a odor.

The types of odor-causing substances are not specific, there are differences in human perceptible concentrations for each substance, and there are different ways to remove them. Therefore, it is almost impossible to remove odor completely. have.

Table 1 below describes the characteristics of representative substances causing odors.

matter Chemical formula Molecular Weight Boiling point
(℃) Solubility in water Odor characteristics Concentration
(ppmv) ammonia NH ₃ 17.03 -33.35 89.9g / 100ml
(0 ℃) Nasal stimulation 1.5 Methyl mercaptan CH ₃ SH 48.11 2.87 41g / 100ml
(21 ℃) garlic
Rotten cabbage 0.00007 Hydrogen sulfide H ₂ S 34.08 -60.33 2.9g / 100ml
(20 ℃) Rotten egg 0.0004 Methyl sulfide (CH ₃ ) ₂ S 62.14 36.20 Trace melting Corruption 0.003 Methyl disulfide (CH ₃ ) ₂ S ₂ 94.14 109 Insoluble Rotting odor 0.0022 Trimethylamine (CH ₃ ) ₃ N 59.11 2.87 41g / 100ml
(19 ℃) Fishy fishy
Rotting odor 0.000032 Acetaldehyde CH ₃ CHO 44.05 21 Available Rotting odor 0.0015 Propionic acid CH ₃ CH ₂ CO0H 74.08 141 Trace melting Irritant smell 0.0057

Conventionally, odorous substances generated by absorption, adsorption, oxidation, etc. are removed. However, odorous substances have different concentrations that cause odors according to their types, and physical characteristics of odorous gases are different. Therefore, it is difficult to completely remove them using absorption or adsorption methods, and wastewater due to secondary pollution by collected odors. I had a problem with waste generation. In addition, oxidative decomposition of malodorous substances using a catalyst or heat is not economical because a large amount of heat is required when the concentration of malodorous substances is low, and there is a problem that high concentrations of sulfur oxides or nitrogen oxides may be generated. There is a need for measures against secondary pollution. That is, there is a lot of difficulties in removing the odor in an easy and inexpensive way because the detection concentration of the odor is too low.

On the other hand, hydrogen sulfide (H ₂ S) is produced when sulfide bacteria present in water decompose sulfuric acid to obtain energy when sewage or wastewater containing sulfate ions are placed in an anaerobic state of low oxygen, or during the decomposition of protein. do.

^{_{SO 4 2- +2 C + 2H 2}} O → 2HCO 3 - + H 2 S

In addition, methyl mercaptan (methanethiol, CH ₃ SH) also occurs during the decomposition of protein weave.

Hydrogen sulphide is mostly emitted to the atmosphere when it is generated in waste water. If oxygen is abundant in the water, the generation of hydrogen sulfide is suppressed. In addition, even though hydrogen sulfide is in equilibrium with the atmosphere and water at room temperature, the hydrogen sulfide present in the water is only a few mg / l.

In removing these odors, oxidizing odorous substances can be converted into odorless substances, and ozone (O ₂ ) is one of the well-known odor removing substances.

Typically, ozone is produced by applying an electric discharge to oxygen or by irradiating ultraviolet rays or the like. At this time, in order to increase the production efficiency of ozone, by reinforcing a facility that can separate only oxygen in the air and concentrate it at an ozone concentration of about 90%, it is possible to produce a high concentration of ozone.

The reaction between ozone and odorous substances is as shown below.

In the case of hydrogen sulfide,

3H ₂ S + O ₃ → 3H ₂ O + 3S

3S + 6O ₃ → 3SO ₂ + 6O ₂

3SO ₂ + 3O ₃ → 3SO ₃ + 3O ₂

3SO ₃ + 2H ₂ O → 3H ₂ SO ₄

In addition, in the case of methyl mercaptan

2CH ₃ SH + O ₃ → (CH ₃ ) ₂ S ₂ + H ₂ O + O ₂

In the case of methyl disulfide

2 (CH ₃ ) ₂ S ₂ + O ₃ + H ₂ O → 2CH ₃ SO ₃ H

In the case of reaction in which hydrogen sulfide and ozone react to generate sulfur, hydrogen sulfide can theoretically be removed with 48 mg of ozone to 102 mg of hydrogen sulfide. That is, assuming that about 5 mg / L of hydrogen sulfide is present in water, only 2.4 mg / L of ozone may be added to remove hydrogen sulfide. However, in the sludge of the sewage treatment plant, there are various materials other than hydrogen sulfide that can react with ozone, so the theoretical input amount cannot be absolute.

In the deodorization using ozone, a method of directly reacting ozone gas with a malodorous substance in a gaseous phase, a method of dissolving ozone gas in water to react with malodorous substances collected in a wet scrubber, and the like are widely used. However, this method also has a limitation in obtaining a complete deodorization efficiency due to low concentration of odorous substances and low solubility of ozone. In particular, the low solubility of ozone is an obstacle in removing ozone by dissolving ozone in water. In addition, ozone released into the atmosphere has been used in a limited way as it may increase the ozone concentration near the ozone gas reactor to the ozone warning level (0.1 ppm) or higher, which may harm worker health.

The present invention is to solve the above-mentioned problems of the prior art by directly incorporating ultra-fine foam ozone into the sewage, wastewater, sewage and sludge during the treatment of wastewater, hydrogen sulfide-based odor including hydrogen sulfide and methyl mercaptan is generated It is an object of the present invention to provide an apparatus and method for removing hydrogen sulfide-based odor using ultra-fine foam ozone.

Hydrogen sulfide-based odor removing apparatus using ultra-fine foam ozone of the present invention for achieving the above object includes a microbubble reactor for mixing ozone with sludge supplied from an anaerobic tank. At this time, the ozone is ultra-saturated through the pump impeller of the microbubble reactor in a state mixed in the sludge through the microbubble reactor.

In the present invention, the ozone is mixed into the sludge using a microbubble reactor, and in the mixing process, ozone is mixed into the sludge in an ultra-fine foam state by a pump impeller to prevent the occurrence of hydrogen sulfide-based odor in the sludge.

The present invention configured as described above can prevent the generation of hydrogen sulfide-based odors including hydrogen sulfide and methyl mercaptan by directly mixing ozone with sewage, waste water, sewage and sludge in the process of treating waste water. In particular, by directly incorporating ozone into a high concentration of odorous substances (sewage, wastewater, sewage and sludge), the reaction of ozone is fast and the reaction effect is excellent, and there is no fear of generation of ozone. In addition, since it is not necessary to install a separate deodorizing tower, it is very effective because it can significantly reduce the installation and operating costs.

1 is a schematic diagram of a hydrogen sulfide-based odor removal device using ultra-fine foam ozone according to an embodiment of the present invention.
Figure 2 is a flow chart of the hydrogen sulfide-based odor removal method using ultra-fine foam ozone according to an embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram of a hydrogen sulfide-based odor removing apparatus using ultra-fine foam ozone according to a preferred embodiment of the present invention.

As shown in FIG. 1, the hydrogen sulfide-based odor removing apparatus using ultra-fine foam ozone includes a microbubble reactor 110 for mixing the sludge supplied from the ozone and activated sludge anaerobic tank 120.

The microbubble reactor 110 is a means for mixing ozone with the sludge supplied from the anaerobic tank 120. That is, ozone is mixed with the sludge supplied from the activated sludge anaerobic tank 120 to block the occurrence of hydrogen sulfide-based odor.

In more detail, the microbubble reactor 110 supersaturates ozone using a pump impeller (not shown) in the process of mixing ozone and sludge. Ultrasaturated saturated ozone through the pump impeller increases the reaction efficiency with the sludge, and reacts with hydrogen sulfide or methyl mercaptan in the sludge to turn into an odorless substance, thereby effectively preventing the occurrence of odor.

At this time, the microbubble reactor 110, more specifically, the size of the ultra-saturated ozone by the pump impeller is preferably 5 ~ 20㎛.

On the other hand, the activated sludge anaerobic tank 120 in which the sludge is stored includes a thickening tank for concentrating the sludge, a dehydration tank for removing water from the sludge, and a return tank for supplying the sludge to the microbubble reactor 110, although not shown in the drawing. It is configured by.

Figure 2 is a flow chart of the hydrogen sulfide-based odor removing method using ultra-fine foam ozone according to an embodiment of the present invention.

1 and 2, in the hydrogen sulfide-based odor removing method using ultra-fine foam ozone according to an embodiment of the present invention, the step of mixing ozone into the sludge (S10) and ultra-saturated saturation of ozone mixed in the sludge It includes a step (S20).

The hydrogen sulfide-based odor removing method using the ultra-fine foam ozone according to the present embodiment, by directly mixing the ozone in the sludge, and by saturating the ozone ultra-saturation to improve the reaction efficiency with the sludge can effectively block odor generation. In particular, generation of hydrogen sulfide-based odors including hydrogen sulfide and methyl mercaptan can be prevented in advance. Therefore, the reaction of ozone is fast and the reaction effect is excellent, and there is no fear of ozone generation.

Hereinafter, the present invention will be described in more detail through Examples 1 and 2 and Comparative Examples using the above-described odor removing apparatus and method of the present invention.

[Comparative Example] Removal of hydrogen sulfide odor from sewage sludge using chemicals

The odor collecting cylinder was prepared with the lower diameter 26cm upper diameter 30cm and the height 29cm volume 18 L so that the measurement conditions of odor were the same. A hole having a diameter of 5 mm was drilled into the upper lid of the barrel, and a odor collecting tube was inserted about 10 cm through the hole to prepare for collecting and analyzing the odor.

Sludge was collected from the concentration tank of the sewage treatment plant, and then put into the odor collecting container, and then covered with a lid, shaken for about 1 minute, and left for about 2 minutes to distribute odorous substances well in the container. And 5 liters of air was taken using the odor collecting equipment and the components were analyzed. The concentration of hydrogen sulfide or methyl mercaptan was analyzed using gas chromatography. This is called one-sludge odor, stored at room temperature and observed the change of odorous substance.

Meanwhile, separately weighed sodium hypochlorite (NaClO) was added to 1 l of sludge collected separately, stirred to be mixed well, and the concentration of the malodorous substance was measured in the same manner as before, and then stored at room temperature.

After 8 hours and after 20 hours, the change of the malodorous substance was observed in each set as follows.

Elapsed time
(hr) One Sludge NaClO
(200ppm) NaClO
(126ppm) 0 600 0 600 8 820 520 Do not measure 20 1,060 750 Do not measure

Table 2 shows the hydrogen sulfide concentration change. Referring to Table 2, in the case of sodium chlorine chlorine can be removed hydrogen sulfide odor if a large amount of oxidizing agent is added, it can be seen that the re-expression of hydrogen sulfide occurs quickly.

[Example 1] Odor removal experiment using ozone

The activated sludge anaerobic tank (120 of FIG. 1) according to this embodiment is filled with 400 l of sludge. The sludge was fed to the microbubble reactor 110 according to the present embodiment and circulated at a rate of 60 l / min. At this time, ozone at a concentration of 48 g / Nm ³ was injected at 2 L / min through the ozone inlet of the microbubble reactor 110 and mixed in the sludge.

At this time, the ozone concentration was measured by the H1-LR model of InUSA. The injected ozone is mixed with the sludge, and in the process, it is supersaturated through a pump impeller (not shown), and the hydrogen sulfide, which is an odorous substance, is oxidized and converted into an odorless substance by the ultra-microporous ozone.

The treated sludge was sampled after the reaction for 10 minutes and 30 minutes, respectively, and the malodor was measured in the same manner as in Comparative Example 1.

One Sludge O ₃
(2.4mg / l) O ₃
(7.1 mg / l) After the reaction 600 0 0 8 820 300 280 20 1,060 410 370

Table 3 shows the hydrogen sulfide concentration change. Referring to Table 3, even when using a low concentration of ozone can remove the hydrogen sulfide odor, it can be seen that the re-expression of the odor is lower than when using sodium chlorine chlorine.

In addition, as a result of observing the state of microorganisms using SOMETECH's image microscope SV 35 in which sludge was added with 7.1 mg / L of ozone, the activity of the microorganisms was similar to that of the original sludge.

Experimental Example 2 Experiment of Confirming Odor Removal Using Ozone

An activated sludge anaerobic tank (120 in FIG. 1) according to this embodiment is charged with 190 l of sludge. The sludge was fed to the microbubble reactor 110 according to the present embodiment and circulated at a rate of 60 l / min. At this time, ozone at a concentration of 50 g / Nm ³ was injected at 1.5 L / min through the ozone inlet of the microbubble reactor 110 and mixed in the sludge. The injected ozone is mixed with the sludge, and in the process, it is supersaturated through a pump impeller (not shown), and the hydrogen sulfide, which is a odorous substance, is oxidized and converted into an odorless substance by the ultra-microscopic ozone.

The treated sludge was sampled after 4 minutes, 8 minutes, and 12 minutes, respectively, and the odor was measured in the same manner as in Comparative Example 1.

One Sludge O ₃
(1.6 mg / l) O ₃
(3.2mg / l) O ₃
(4.8 mg / l) H2S (ppmv) 240 20 ND ND RSH (ppmv) 4.5 2.5 0.7 ND

The dissolved oxygen concentration in the raw sludge of the thickener was 0 ppm. Dissolved oxygen was measured by DO 24 dissolved oxygen concentration meter of DKK-TOA of Japan. When 3.2 mg / l of ozone was added, the dissolved oxygen in the water was 15 mg / l, and oxygen was consumed by the microorganisms in the water, and the dissolved oxygen concentration became zero after 30 minutes. There was no change in dissolved oxygen. This can be inferred that the oxygen remaining in the ozone reaction is dissolved in the water as fine bubbles and thus has an effect of delaying the appearance of odor due to increasing the dissolved oxygen concentration in the sludge.

While the present invention has been described through the preferred embodiments, the above-described embodiments are merely illustrative of the technical idea of the present invention, and various changes may be made without departing from the technical idea of the present invention. Those of ordinary skill will understand. Therefore, the protection scope of the present invention should be interpreted not by the specific embodiments, but by the matters described in the claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

110: microbubble generator 120: activated sludge anaerobic tank

Claims (8)

It includes a microbubble reactor for mixing ozone into the sludge supplied from the anaerobic tank, the microbubble reactor to generate the hydrogen sulfide-based odor by ultra-saturating the ozone using a pump impeller in the process of mixing ozone and sludge Block it,
Ultrasonic foam ozone generated in the microbubble reactor has a size of 5 ~ 20㎛, the ultra-fine foam ozone mixed is 1 ~ 10mg per 1L of sludge hydrogen sulfide-based odor removing device using ultra-fine foam ozone .
delete delete The method according to claim 1,
The activated sludge anaerobic tank is a hydrogen sulfide-based odor removing apparatus using ultra-fine foam ozone, characterized in that the concentration tank to concentrate the sludge, a dehydration tank for removing the water of the sludge, and a return tank for supplying the sludge to the microbubble reactor. Incorporating ozone into the sludge; And
Including the ultra-saturation saturation of ozone mixed in the sludge, by blocking the generation of hydrogen sulfide-based odor by saturating ozone in the process of mixing ozone and sludge,
The ultra-fine foam ozone has a size of 5 ~ 20㎛, the ultra-fine foam ozone is a hydrogen sulfide-based odor removing method characterized in that the mixture of 1 ~ 10mg per 1 liter of sludge.
delete delete The method according to claim 5,
Hydrogen sulfide-based odor removal method using ultra-fine foam ozone, characterized in that the hydrogen sulfide-based odor is hydrogen sulfide or methyl mercaptan.

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