JP2005144423A - Deodorizer and deodorizing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a deodorizer immediately deodorizing hydrogen sulfide, methyl mercaptan, or the like, generated from a sewage treatment plant, human waste treatment plant, food factory, paper pulp plant, or the like, while maintaining a deodorant effect and causing no environmental problem. <P>SOLUTION: The deodorizer contains an azide compound such as sodium azide, potassium azide, or azide hydrogen acid. When sludge is deodorized, e.g. 10-500 mg/L of the azide compound is preferably added to the sludge, or more preferably, 20-200 mg/L thereof is added thereto. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention deodorizes malodorous substances such as hydrogen sulfide, methyl mercaptan, etc. generated from sewage treatment plants, human waste treatment plants, food factories, paper pulp factories, etc. The present invention relates to a deodorizing agent and a deodorizing method that can improve odor.

  Conventionally, a method using a heavy metal salt such as a zinc compound or an iron compound has been generally used to deodorize a malodorous substance such as hydrogen sulfide or methyl mercaptan. However, these methods have an excellent deodorizing effect, but when the dehydrated cake obtained by treating the sludge with these heavy metal salts is discarded to the final disposal site, the heavy metal used from the dehydrated cake is eluted, creating a new environment to the surroundings. There is a problem that causes contamination. In addition, there is a concern that these compounds corrode the processing equipment. Further, when the dehydrated cake is incinerated, metal compounds such as zinc and iron are scattered in the atmosphere and remain in the incinerated ash, so these measures are necessary.

In recent years, since the disposal method of the dehydrated cake has shifted to incineration and melting methods, deodorizers are changing from metal salts to non-metals. Specific examples of chemicals used are mainly oxidizing agents such as hydrogen peroxide in the case of oxygen and sodium hypochlorite and chlorine dioxide in the case of chlorine. These are excellent in that the odor can be immediately extinguished, but the deodorizing effect is not maintained, and hydrogen sulfide can be easily deodorized, but the effect of deodorizing methyl mercaptan is insufficient. Have In order to solve these problems, a method of treating a solution sulfur-based malodor component in which nitrate is added to hydrogen peroxide has been proposed. (For example, see Patent Document 1) However, the effect using the hydrogen peroxide-nitrate is also insufficient. Other than the oxidizing agent, a method using a reducing agent such as nitrite and sulfite has been proposed. In the method using these reducing agents, the deodorizing effect retention time of the dehydrated cake has been improved to some extent, but for that purpose, a large amount of these reducing agents is required and it takes a long time to complete the deodorization. Has drawbacks. (For example, see Patent Document 2)
JP-A-10-216698 JP-A-12-202494

  As described above, in the conventional technology, the deodorizing effect is insufficient, or there is a lack of consideration for the environment even if there is a deodorizing effect. . An object of the present invention is to provide a deodorizing agent that has an effect of suppressing the generation of sulfur-based malodorous substances over a long period of time and has no adverse effect on the environment.

  The present invention has repeated research on methods for deodorizing odors such as hydrogen sulfide and methyl mercaptan, which are malodorous substances generated from wastewater or sludge from sewage treatment plants and human waste treatment plants, in a non-metallic system and a non-oxidizing system. As a result, it was found that by adding an azide compound to the sludge, it is possible to suppress the generation of sulfur-based malodorous substances over a long period of time, and that the time until deodorization is completed is short, and the present invention Was completed.

  That is, the present invention relates to a deodorizing agent and a deodorizing method for sulfur-based malodorous substances composed of an azide compound. In this method, an azide compound is added to sludge containing a sulfur-based malodorous substance so that the sludge can be deodorized over a long period of time. The azide compound is sodium azide, potassium azide, or hydrazoic acid.

  According to the present invention, sulfur-based malodorous substances such as hydrogen sulfide and methyl mercaptan can be deodorized with an azide compound over a long period of time. By adding the deodorizing agent of the present invention to raw sludge, surplus sludge and digested sludge generated in sewage and human waste treatment, the generation of sulfur-based malodorous substances generated therefrom can be suppressed. The time for completing the deodorization was 3 to 5 minutes in a short time.

  The azide compound of the deodorizer of the present invention is sodium azide, potassium azide or hydrazoic acid, and among them, sodium azide is most preferable. The rate of addition of the azide compound depends on the amount of sulfur-based malodorous substances in the target sludge. For example, in the case of sodium azide, it is generally 10 to 500 mg / L with respect to the sludge. Is more preferable, and 20 to 200 mg / L is more preferable. The concentration of the aqueous sodium azide solution used is preferably a 20% to 30% solution.

  When the sodium azide used in the present invention is added to the sludge, the use of a surfactant is effective in increasing the reaction efficiency with the sludge. The surfactant is, for example, a low-bubble nonionic surfactant. The addition rate of the surfactant is preferably 5 mg / L to 50 mg / L with respect to the sludge. In addition, sodium azide is effectively added to a solution adjusted to a concentration of 20% to 30% and diluted 5 to 10 times when added to sludge.

  The location where the azide compound is added may be a sludge storage tank, a flocculant addition location, a sludge transport pipeline, etc., but the location is not particularly limited, and the location where the sludge and the deodorizer of the present invention are mixed If so, the addition location may be any location.

  The deodorizer of the present invention can be suitably used for sewage and raw sludge generated in the treatment of human waste, surplus sludge, digested sludge, but is not limited to these sludges, sulfur-based malodorous substances It can also be applied to other sludges, wastes, and exhaust materials that generate water.

Hereinafter, the present invention will be described with reference to Examples 1 to 6.
500 ml of adjusted sludge obtained by mixing raw concentrated sludge and surplus sludge obtained at a sewage treatment plant at a weight ratio of 1: 1 is put into a 1 liter (L) Erlenmeyer flask, and after adding the deodorizer shown in Table 2, it is a glass rod for 30 seconds. Then, 200 ppm of cationic polymer flocculant is added to the adjusted sludge, followed by filtration and dehydration to obtain a dehydrated cake. 5 g of this dehydrated cake was placed in a 500 ml Erlenmeyer flask and sealed with a polyvinylidene chloride wrap, and the gas concentrations of hydrogen sulfide and methyl mercaptan after 24 hours and 48 hours were measured with a gas detector tube.

Claims (4)

    Deodorizer for sulfurous malodorous substance containing azide compound.     The deodorizer according to claim 1, wherein the azide compound is sodium azide, potassium azide or hydrazoic acid.     The deodorizer according to claim 1 or 2, comprising a surfactant.     A method for deodorizing a sulfur-based malodorous substance, comprising adding an azide compound to waste water or sludge.