JP4523889B2 - Deodorizing method and deodorizing agent - Google Patents

Description

  The present invention relates to a deodorizing method and a deodorizing agent for malodorous gas, but it generates odors such as waste water, sludge, garbage, manure, etc. generated in human waste treatment plants, sewage treatment plants, paper mills, food factories, livestock breeding farms, etc. It is preferably used for the source deodorization treatment.

  For example, in a sewage treatment facility that performs biological treatment of organic wastewater, surplus activated sludge is generated, and this surplus sludge is concentrated and dehydrated and transported, but the removed sludge (dehydrated cake) is temporarily removed. In the case of storage, the sludge decays, and malodorous gases such as hydrogen sulfide and methyl mercaptan are generated.

  In order to prevent the generation of this malodorous gas, a method for deodorizing a dehydrated cake by bringing a deodorant containing a pyrithione compound as an active ingredient into contact with sludge has been proposed (for example, Patent Document 1). However, since such a pyrithione compound has an excellent effect of suppressing sludge decay, it is an expensive drug. Therefore, when it is used for a deodorizing treatment, there is a problem that it costs a drug.

JP-A-7-185329

  An object of this invention is to reduce the chemical | medical agent cost required for this process by reducing the usage-amount of the pyrithione compound required for a deodorizing process.

  As a result of intensive studies to solve the above problems, the present invention has found that glyoxylic acid, which is a surprisingly inexpensive drug, dramatically improves the anti-corrosion function of pyrithione compounds, and completes the present invention. It has come. That is, the present invention is a deodorizing method characterized in that a malodor generating source is brought into contact with a pyrithione compound and glyoxylic acid, thereby suppressing the decay of the generating source and preventing the generation of malodorous gas. The second invention is a deodorizer characterized by containing a pyrithione compound and glyoxylic acid. And 3rd invention makes content of glyoxylic acid 0.1-20 times weight with respect to content of a pyrithione compound in 2nd invention.

  According to the present invention, by using glyoxylic acid in combination, the deodorizing ability of the pyrithione compound can be increased, so that the amount of the pyrithione compound used can be reduced. Therefore, the chemical cost required for the deodorizing process can be reduced.

Hereinafter, the present invention will be described in detail.
The pyrithione compound used in the practice of the present invention refers to pyrithione, a dimer of pyrithione and a metal salt of pyrithione. Pyrithione represents 2-mercaptopyridine-1-oxide or 1-hydroxy-2 (1H) -pyridinethione represented by the chemical formula of Chemical Formula 1, and these compound names are derived from the tautomeric structure of pyrithione. . The dimer of pyrithione is a dimer of 2-mercaptopyridine-1-oxide represented by the chemical formula of Chemical Formula 2. The metal salt of pyrithione is a compound represented by the chemical formula of Chemical Formula 3.

（但し、式中のＭは、リチウム、ナトリウム、カリウム、銅、マグネシウム、カルシウム、バリウム、亜鉛、アルミニウム、スズ、マンガン、鉄を表す。ｎは１〜４の整数を表す）

(However, M in the formula represents lithium, sodium, potassium, copper, magnesium, calcium, barium, zinc, aluminum, tin, manganese, or iron. N represents an integer of 1 to 4)

These pyrithione compounds are known to have a function to prevent the growth of microorganisms (antibacterial function), and are added as antibacterial agents and preservatives to paints, adhesives, cosmetics, fragrances, metal working fluids, etc. Yes. In particular, zinc pyrithione is added to hair cosmetics as an anti-dandruff agent, and is also used as an antifouling agent for marine paints.
In the practice of the present invention, among the metal salts of pyrithione, zinc pyrithione when M is zinc, copper pyrithione when M is copper, and sodium pyrithione when M is sodium are industrially easy. It is preferable in terms of availability.

  Glyoxylic acid used in the practice of the present invention is represented by the chemical formula of Chemical Formula 4 and is used as a fragrance (vanillin, ethyl vanillin) raw material, a pharmaceutical (antibiotic) raw material, a deodorizing (deodorizing, deodorizing) agent, etc. It is easily available as an industrial chemical. The drug unit price of glyoxylic acid is about one-tenth of the drug unit price of the pyrithione compound when compared in terms of solid content.

  By the way, various studies on deodorizers containing glyoxylic acid as an active ingredient have been conducted. However, as described in, for example, JP-A-10-66866, glyoxylic acid is adapted to deodorizing treatment with a function of chemically deodorizing and removing malodorous components or physically adsorbing or absorbing malodorous components. And about the effect | action which increases the antibacterial function which prevents the decay which a pyrithione compound has, and improves a deodorizing effect, it is the knowledge which this inventor etc. discovered newly.

  In the practice of the present invention, there is no particular limitation on the method of contacting the malodor generating source with the pyrithione compound and glyoxylic acid, and after adding the pyrithione compound and glyoxylic acid to the malodor generating source by a method such as spraying or spraying, stirring, mixing operation, etc. Therefore, it is desirable that the deodorizing agent is uniformly brought into contact with the malodor generating source. There is no restriction | limiting in the order of addition of a pyrithione compound and glyoxylic acid, What is necessary is just to add both sequentially or simultaneously. In addition, if it mixes a pyrithione compound and glyoxylic acid beforehand and it is set as the deodorizer containing both, it is convenient in the point of the ease of handling.

In carrying out the deodorizing method of the present invention, the amount of glyoxylic acid used is preferably 0.1 to 20 times weight (in terms of solid content) relative to the pyrithione compound, more preferably 1 to 10 times weight. Is the ratio. If the proportion of glyoxylic acid is lower than 0.1 times the weight, the deodorizing effect of the pyrithione compound cannot be enhanced, and even if it exceeds 20 times the weight, only the amount of glyoxylic acid used is increased and the pyrithione compound is increased. The deodorizing effect cannot be increased.
Moreover, when implementing to the deodorizing agent of this invention, it is preferable to make content of glyoxylic acid 0.1-20 times weight (solid content conversion) like the above with respect to content of a pyrithione compound.

  The total amount of pyrithione compound and glyoxylic acid added to the malodorous source (in terms of solid content) varies depending on the type and amount of the malodorous substance generated due to the type and amount of organic matter contained in the malodorous source. Is preferably in the range of 10 to 10,000 mg per unit volume (l) or unit weight (kg) of the malodor generating source, but may be increased or decreased as appropriate.

  There are no particular restrictions on the source of malodorous odor (object to be treated) to which the present invention is applied, and wastewater, sludge, garbage, manure generated at human waste treatment plants, sewage treatment plants, paper mills, food factories, livestock breeding yard, etc. For example, it can be applied to those in which corruption occurs due to the propagation of microorganisms.

  In the practice of the deodorizer of the present invention, a surfactant can be used to uniformly mix the pyrithione compound and glyoxylic acid and enhance storage stability. Surfactants include anionic surfactants such as alkyl sulfates, cationic surfactants such as alkyltrimethylammonium chloride, amphoteric surfactants such as alkyldimethylaminoacetic acid betaine, and nonionic interfaces such as glycerin fatty acid esters. An activator is mentioned. These may be used alone or in combination of two or more. The content of the surfactant in the deodorizer is preferably 0.01 to 3% by weight, more preferably 0.1 to 1% by weight.

Although there is no restriction | limiting in particular in the aspect of the deodorizer of this invention, When using the glyoxylic acid aqueous solution which can be obtained industrially, it is preferable to set it as a liquid agent. Further, it can be diluted several to several tens of times with water depending on the purpose of use, application, etc., and a lower alcohol such as ethanol or isopropanol can be added.
Furthermore, it can be used after being impregnated and supported on a porous carrier such as activated carbon, silica gel, zeolite, etc. to form a powder, tablet or granule.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to comparative examples and examples, but the present invention is not limited thereto. In addition, the chemical | medical agent used in the comparative example and the Example is the following. The deodorization test method is as follows.

[Drug]
・ Pyrithione (manufactured by Tokyo Chemical Industry Co., Ltd., reagent grade 1)
・ Zinc pyrithione (Tokyo Chemical Industry Co., Ltd., reagent grade 1)
・ Copper pyrithione (manufactured by Arch Chemical Co.)
・ Sodium pyritin (manufactured by Tokyo Chemical Industry Co., Ltd., reagent, 35% aqueous solution)
・ Glyoxylic acid (manufactured by Tokyo Chemical Industry Co., Ltd., reagent, 40% aqueous solution)

[Deodorization test]
1000 ml of activated sludge slurry (MLSS: 22,000 mg / l, pH 4.6) collected from the sewage treatment plant was placed in a 2 L beaker, and then a predetermined amount of deodorizer was added and mixed. Next, 10 ml of a 1% by weight aqueous solution of a cationic flocculant (manufactured by Toagosei Chemical Co., Ltd., trade name “Aron Flock C303”) was added, and the mixture was stirred at 300 rpm for 30 seconds using a stirrer to coagulate sludge. This activated sludge slurry was dehydrated at 3,000 rpm for 15 minutes using a centrifuge to obtain a dehydrated cake.
60 g of the dehydrated cake taken out is put into a 2 L wide-mouthed bottle, stored in a thermostatic chamber adjusted to 35 ° C., and the gas concentrations of hydrogen sulfide and methyl mercaptan in the wide-mouthed bottle after 24 and 48 hours have passed. Measurement was performed using a detector tube. The gas detection tubes 4M, 4L, and 4LL manufactured by Gastec Corporation were used for measurement of hydrogen sulfide, and the detection tubes 71 and 71H manufactured by the same company were used for measurement of methyl mercaptan.
Since the amount of hydrogen sulfide and methyl mercaptan generated (air concentration) decreases as the deodorizing cake is prevented from being spoiled by the addition of the deodorizing agent, it is determined that the function as the deodorizing agent has been exhibited.

[Comparative Example 1]
As a deodorizer, pyrithione was added to the activated sludge slurry so as to have an amount shown in Table 1, and a deodorization test was conducted. The obtained test results are as shown in Table 1. The greater the amount of pyrithione added, the lower the malodorous gas concentration. When the amount of pyrithione added was 60 mg / l, the malodorous gas concentration was almost equal. The concentration dropped below the level detectable by the gas detector tube.
In addition, the result of the blank test when not using a deodorizer is test No. in Table 1. 1 as shown.

[Comparative Examples 2 to 4]
A deodorization test was conducted in the same manner as in Comparative Example 1 except that zinc pyrithione, copper pyrithione and sodium pyrithione were used instead of pyrithione. The obtained test results are as shown in Tables 2 to 4, respectively, the more the amount of zinc pyrithione, copper pyrithione, and sodium pyrithione, the lower the malodorous gas concentration, and the amount of the pyrithione compound added was 60 mg / l. In this case, the concentration of the malodorous gas was lowered to a concentration that is almost detectable by the gas detector tube.

[Comparative Example 5]
A deodorization test was conducted in the same manner as in Comparative Example 1 except that glyoxylic acid was used instead of pyrithione. The obtained test results are as shown in Table 5, and it is recognized that the malodorous gas concentration tends to decrease as the amount of glyoxylic acid added increases. However, the deodorizing function of glyoxylic acid is clearly inferior to that of the aforementioned pyrithione compound.

[Example 1]
In the same manner as in Comparative Example 1, pyrithione and glyoxylic acid as deodorizers were added to the activated sludge slurry so as to have the amounts shown in Table 6 (in terms of solid content), and a deodorization test was performed. Was as shown in Table 6.

[Examples 2 to 4]
A deodorization test was conducted in the same manner as in Example 1 except that zinc pyrithione, copper pyrithione and sodium pyrithione were used instead of pyrithione. The obtained test results were as shown in Tables 7 to 9, respectively. .

According to the test results of Examples 1 to 4, glyoxylic acid compared to the case where only 10 mg / l each of pyrithione, zinc pyrithione, copper pyrithione and sodium pyrithione was added (see Test No. 1 of Comparative Examples 1 to 4). When used together, the deodorizing effect of these pyrithione compounds was dramatically improved. In addition, when 200 g / l of glyoxylic acid is added, that is, when 20 times the weight of the pyrithione compound is added, the concentration of hydrogen sulfide and methyl mercaptan in air is reduced below the detection limit concentration of the gas detector tube. did.
For example, when the amount of pyrithione compound used is 10 mg / l and the amount of glyoxylic acid used is 10 mg / l (see Test No. 4 in Examples 1 to 4), when only 40 mg / l of the pyrithione compound is used ( Since a deodorizing effect equivalent to that in Test No. 5 of Comparative Example 1 and Test No. 4 of Comparative Examples 2 to 4 is obtained, the amount of pyrithione compound used can be reduced to about one-fourth. In this case, considering that the drug unit price of glyoxylic acid is about one-tenth of the drug unit price of the pyrithione compound, the drug cost of the deodorizer can be reduced to about one-fourth.
When the amount of pyrithione compound used is 10 mg / l and the amount of glyoxylic acid used is 100 mg / l (see Test No. 7 in Examples 1 to 4), only the pyrithione compound is used at 60 mg / l. Since a deodorizing effect equivalent to that of Test No. 7 of Comparative Example 1 and Test No. 6 of Comparative Examples 2 to 4 is obtained, the amount of pyrithione compound used can be reduced to about 1/6. . In this case, the chemical cost of the deodorant can be reduced to about one third by the same situation as described above.

Example 5
Water, a pyrithione compound, glyoxylic acid and a polyoxyethylene sorbitan fatty acid ester as a surfactant were mixed to prepare deodorizers A to C containing the above components in the composition ratios (% by weight) shown in Table 10. .
The excess sludge generated at the wastewater treatment facility in the food factory was dewatered with a belt press. The obtained dehydrated cake was cut into a substantially square shape (about 5 × 5 cm, about 50 g), and the deodorizer was sprayed on both sides of the dehydrated cake using a sprayer. Moreover, the addition amount of the deodorizing agent was calculated from the weight of the dehydrated cake before and after the spraying of the deodorizing agent.
Next, after putting a part (30 g) of the dehydrated cake sprayed with the deodorizer into a 1 L wide-mouthed bottle, storing it in a thermostatic chamber adjusted to 35 ° C., and after 24 hours, 48 hours and 72 hours, The air concentration of hydrogen sulfide and methyl mercaptan in the bottle was measured with a gas detector tube.
The obtained test results are as shown in Table 11, and any deodorizing agent was able to suppress the generation of malodorous gas from the dehydrated cake over 3 days.

Claims (3)

A deodorizing method characterized by contacting a pyrithione compound and glyoxylic acid with a malodor generating source to suppress the spoilage of the generating source and preventing generation of malodorous gas. A deodorizing agent comprising a pyrithione compound and glyoxylic acid. The deodorizer according to claim 2, wherein the content of glyoxylic acid is 0.1 to 20 times the weight of the content of the pyrithione compound.