JP4577927B2 - Odor gas deodorization method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an odor gas deodorization method, and more particularly to an odor gas deodorization method using non-membrane electrolyzed water.
[0002]
[Prior art]
Conventionally, not only deodorization of odorous gas generated from malodorous sources typified by organic wastewater treatment facilities, but also more general methods for air purification include alkaline water and acidic water produced by water electrolysis. The deodorizing method used is proposed (for example, Unexamined-Japanese-Patent No. 6-210125, Unexamined-Japanese-Patent No. 10-128029). These methods are excellent methods that do not use chemicals for deodorization, but they are not satisfactory in terms of deodorizing effect, and the activity of alkaline water or acidic water lasts for a long time. Therefore, there was a drawback that the energy cost was high.
[0003]
That is, in the above method, water is first electrolyzed using a diaphragm, and malodorous gas is passed through the obtained alkaline water or acidic water. However, the activity time of the alkaline water or acidic water is short. Therefore, it was necessary to change the alkaline water and acidic water to new ones frequently. In order to alleviate such disadvantages in terms of energy costs, treated water treated in a wastewater treatment facility is also used as water to be electrolyzed, but even in this case, energy costs are essentially reduced. There was a drawback that it could not be lowered.
[0004]
[Problems to be solved by the invention]
While the present inventors have studied to improve the above-mentioned drawbacks, the electrolyzed water produced without using a diaphragm is remarkably superior to conventional alkaline water and acidic water, and has a sufficiently long duration of activity. The present invention was found.
Accordingly, an object of the present invention is to provide a method for deodorizing odor gas which is simple and does not use any chemicals and has an excellent deodorizing effect.
[0005]
[Means for Solving the Problems]
The above object of the present invention is to produce electrolyzed diaphragm water having a pH of 7.5 to 8.5 and a redox potential value of 650 to 800 mV, which is produced by electrolyzing water without using a diaphragm. This was achieved by a method of deodorizing odor gas characterized by passing odor gas through the odor gas.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Electrolyzed water generally means water produced when water is electrolyzed, but electrolyzed water also varies depending on whether a diaphragm is disposed between the electrodes during electrolysis. Usually, electrolyzed water called acidic water or alkaline water is electrolyzed water obtained on the anode side or the cathode side when a diaphragm is disposed between the electrodes and water in which an alkali metal salt such as sodium chloride is dissolved is electrolyzed. It is known that the pH of acidic water is less than 3 and ORP (redox potential) exceeds 1,100 mV, the pH of alkaline water exceeds 11 and ORP is less than -800 mV.
[0007]
On the other hand, when the same water is electrolyzed without a diaphragm, electrolyzed water having a pH of 7.5 to 8.5 and an ORP of 650 to 800 mV is obtained. This electrolyzed water is electrolyzed water used in the present invention.
As one of the conventional deodorizing methods, a deodorizing method using a neutralization reaction of chemicals has been known. Therefore, acidic water having an acidic pH and alkaline water having an alkaline property have attracted attention. Has been used. On the other hand, in the case of the diaphragm electrolyzed water of the present invention, which shows weak alkalinity, there was a history that it was not used for deodorization because almost no neutralizing power such as acidic water or alkaline water was observed. In the present invention, for the first time, it succeeded in deodorizing utilizing the oxidation reaction of electrolyzed membrane water.
[0008]
Therefore, the diaphragm electrolyzed water per se in the present invention is known per se and can be appropriately produced by a known method. However, the deodorizing ability utilizes a neutralization reaction as demonstrated by Examples and Comparative Examples described later. It is orders of magnitude larger than acidic and alkaline water. In particular, from the viewpoint of sustaining activity when used for deodorization, the pH after electrolysis is preferably weakly alkaline.
[0009]
When deodorizing odors in normal living spaces such as odors of cigarettes, normal water such as tap water may be used as the raw water for electrolysis, but organic wastewater treatment such as human waste, sewage, and industrial wastewater Since it is expensive to use tap water or the like for bad odors emitted from the facility, it is preferable to use treated water from the facility or the like as raw water for electrolysis water. Even in this case, the electrolyzed water after being used for deodorization sufficiently satisfies the drainage standard and can be discharged into the river.
[0010]
The deodorizing conditions in the present invention are not particularly limited, and the temperature of the electrolyzed water and the space velocity of the odor gas passing through the electrolyzed water may be determined as appropriate, but the temperature of the electrolyzed water should be about room temperature. Above preferred. The deodorizing effect of the electrolyzed water in the present invention can be managed by ORP. Therefore, the ORP is constantly measured, and when this value falls below the reference value, the entire electrolyzed water can be promptly replaced with new electrolyzed water . A method of draining old electrolyzed water from the upstream side from the upstream side can also be adopted.
[0011]
The method of the present invention may be used at any place as long as the purpose is deodorization, but it is natural that the structure and system configuration of the deodorization apparatus differ depending on the place of use. Then, as an example, the case where this invention is utilized for the waste water treatment facility using activated sludge is demonstrated according to a figure.
[0012]
FIG. 1 is a conceptual diagram of a system when the present invention is used in a wastewater treatment facility using activated sludge. As is clear from this figure, the odor discharged from the sand settling tank, raw water pump tank, flow rate adjustment tank, sludge storage tank, sludge concentration tank, sludge dewatering machine, etc. is the deodorizing device using the diaphragm electrolyzed water in the present invention. Can handle all. In this case, it is preferable to use treated water as raw water for electrolysis water. In addition, the deodorizing device does not require a special structure, and a known device may be used as it is, but it is not necessary to divide into acidic water and alkaline water, so the device is reduced in size and simplified accordingly. be able to.
[0013]
【The invention's effect】
The deodorizing method of the present invention not only uses a chemical, but also has a low running cost. Since the deodorizing ability is high, the deodorizing method can sufficiently follow even if the amount of inflowing gas fluctuates, and the apparatus is simplified as compared with the conventional method. There is an advantage that it is miniaturized. Furthermore, since the electrolyzed water after the deodorizing treatment sufficiently satisfies the drainage standard, it can be discharged into a river.
[0014]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in full detail, this invention is not limited by this.
[0015]
Example 1.
In a water tank containing 1 liter of electrolyzed water having a pH of 8.4 at 26.9 ° C. and an ORP of 715 mV, obtained by electroless membrane electrolysis, 30 ppm of hydrogen sulfide (H ₂ S), 4 ppm of methyl mercaptan (MM) and Odorous air (simply abbreviated as gas) containing 0.6 ppm of ammonia was injected at a space velocity of 3.6 liters / minute. At this time, the dependence of the pH, ORP and H ₂ S removal rate of the water tank on the gas inflow (liter) was measured.
Each result is as having shown in FIGS. As is clear from FIG. 3, it was demonstrated that the deodorization method of the present invention can be sufficiently managed by ORP.
[0016]
Comparative Example 1
When the same malodor removal test as in Example 1 was performed using 1 liter of acidic water or alkaline water obtained by electrolysis with a gap between the electrodes, it was effective only for a short time. Each measurement was performed at a speed as low as 0.72 liter / min. The results are as shown in FIG. 5, and it was confirmed that the deodorizing effect was significantly inferior to that of the present invention. The pH of the acidic water used at 27.3 ° C. was 2.48, ORP was 1,120 mV, the pH of alkaline water at 27.6 ° was 11.45, and ORP was −898 mV.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram when the deodorizing method of the present invention is applied to a sewage purification facility.
2 is a graph showing the gas flow rate dependence of the pH of electrolyzed water in the deodorizing work of bad odor air in Example 1. FIG.
FIG. 3 is a graph showing the dependency of the ORP of electrolyzed water on the gas flow rate in the deodorizing work of bad odor air in Example 1.
4 is a graph showing the gas flow rate dependency of the H ₂ S removal rate of electrolyzed water in the deodorizing work of bad odor air in Example 1. FIG.
5 is a graph showing the gas flow rate dependence of the H ₂ S removal rate of electrolyzed water in the deodorizing work of malodorous air in Comparative Example 1. FIG.
[Explanation of symbols]
1 Sedimentation tank 2 Raw water pump tank 3 Flow rate adjustment tank 4 Aeration tank 5 Sedimentation tank 6 Sludge storage tank 7 Sludge concentration tank 8 Sludge dewatering machine 9 Deodorizer

Claims (4)

Water without the diaphragm was produced by electrolyzing, a diaphragm-free electrolytic water value of the redox potential to a pH of 7.5 to 8.5 is a 650～800MV, the passing odorous gas Characterized odor gas deodorization method.   The odor gas deodorizing method according to claim 1, wherein the diaphragm electrolyzed water is electrolyzed water produced by subjecting the treated water treated in an organic wastewater treatment facility to electroless membrane electrolysis. Wherein as the value of the redox electric position of the electrolytic water is always 650～800MV, adding a new electrolytic water on the upstream side of the deodorizing apparatus, draining the old electrolytic water from the downstream side, according to claim 1 or 2 Of deodorized odor gas. By electrolyzing the treated water after treatment in an organic wastewater treatment facility, electrolyzed water having a pH of 7.5 to 8.5 and a redox potential value of 650 to 800 mV is produced. A method for deodorizing an odor gas for an organic wastewater treatment facility, wherein the odor gas generated in each treatment step in the treatment facility is passed through the electrolytic water.

Images