JPS63209798A - sludge deodorizer - Google Patents

Abstract

PURPOSE:To prevent anaerobic decomposition of org. matter and release of malodors (methyl mercaptan, hydrogen sulfide, methyl sulfide, etc.) by using a sludge deodorizer contg. an isothiazolone compd. or the salt thereof as an effective component. CONSTITUTION:The isothiazolone compd. expressed by the formula (e.g., 3- isothiazolone) or the salt thereof is incorporated as the effective component into the sludge deodorizer. (R1 denotes H or alkyl group of 1-18C, R2, R3 denote H, halogen atom or alkyl group of 1-4C, R2 and R3 may be combined to denote a benzene ring). This sludge deodorizer is capable of prohibiting the generation of malodors from the root thereof by directly acting on the septic bacteria and sulfate-reducing bacteria which anaerobically decompose the org. matter and generate the malodors, thereby suppressing the action thereof. The sludge deodorizer is also capable of suppressing the generation of the malodors from the dehydrated cake.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a sludge deodorizer that prevents sludge from being decomposed anaerobically and releasing bad odors (methyl mercaptan, hydrogen sulfide, methyl sulfide, etc.).

[Conventional technology]

Sewage, human waste, and organic industrial wastewater are treated in treatment facilities, producing various types of sludge. For example, when raw water is led to a primary settling tank for solid-liquid separation, primary settling tank sludge is generated. The sludge that has passed through the initial settling tank is usually mixed with activated sludge, subjected to aeration, and separated into solid and liquid in the final settling tank. A portion is returned, but the remainder becomes surplus sludge. In addition to these, there are sludge extracted from a digestion tank that is generated when raw water such as human waste or excess sludge is anaerobically digested, and flocculated sludge that is generated when raw water or treated water is flocculated.

These sludges are dehydrated using dehydrators such as centrifuges, filter presses, and belt presses, and the dehydrated cakes are incinerated or disposed of in landfills. During the sludge dewatering process and the storage and transportation of the dehydrated cake, the odor generated sometimes deteriorates the working environment. For this reason, the odors have been sucked in and treated with adsorbents, or the bad odors generated have been masked with aromatics, perfumes, etc.

[Problem that the invention seeks to solve]

However, the method of separately deodorizing the odor by suctioning it requires large-sized equipment and increases costs. Also,
Although the method of using masking agents improves quality,
Since the malodorous components themselves did not change and the odor concentration did not decrease, it was not possible to prevent the odor from spreading to the surrounding area. In particular, since the dehydrated cake is temporarily collected or transported, it has been difficult to deal with the problem sufficiently using methods such as suctioning the odor and disposing of it separately, or using masking agents. Therefore, there was a need to eliminate the generation of bad odors from the source.

[Means for solving problems]

The present invention is a sludge deodorizer containing an isothiazolone compound represented by the following general formula (I) or a salt thereof as an active ingredient.

(In the formula, R1 represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, R7 and R1 represent a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms, and R2 and R1 together represent a benzene ring. ) Isothiazolone compounds that can be used in this invention include:
Examples include:

3-isothiazolone 2-methyl-3-inchazolone 2-ethyl-3-inchazolone 2-propyl-3-inchazolone 2-butyl-3-isothiazolone 2-octyl-3-isothiazolone 2-decyl-3-isothiazolone 2-octadecyl-3 -isothiazolone 4-chloro-2
-Methyl-3-isothiazolone 4-bromo-2-methyl-3-isothiazolone 5-chloro-2-methyl-3-isothiazolone 4-bromo-5-chloro-2-methyl-3
-isothiazolone 1,2-benziisothiazolone 2-ethyl-1,2-benziisothiazolone Salts of isothiazolone compounds include, for example, amine salts, alkali metal salts, and complexes with metal salts. Metal salts that form complexes with isothiazolone compounds include zinc chloride, zinc bromide, and copper chloride.

Examples include magnesium chloride and calcium chloride.

Examples of preferred compounds used in this invention include 1.2-benziisothiazolone dimethylamine salt, 1
．． 2-Benzisothiazolone ethylenediamine salt, 1
, 2-benzisothiazolone sodium salt, and the like.

The amount of the sludge deodorizer of this invention added is 10 to 2,00 Onag/ as the compound of general formula (+) or its salt.
Q level is sufficient.

[For production]

When the sludge deodorizer of this invention is added to sludge and mixed, the active ingredient exhibits strong inhibitory power against putrefactive bacteria and sulfate-reducing bacteria, and organic matter decomposes anaerobically to produce methyl mercaptan.
Prevents generation of methyl sulfide, etc., and prevents sulfate from being reduced and hydrogen sulfide generated.

It is also believed that small amounts of odor generated are decomposed and removed by chemical reactions.

[Example 1] 30 mg/Q of 1,2-penziisothiazolone dimethylamine salt was added to a mixture of sewage primary sedimentation tank sludge, surplus sludge of activated sludge, and sludge extracted from anaerobic digestion of surplus sludge. After mixing, a polymer flocculant was added to form flocs, and the mixture was fed to a belt press type dehydrator for dehydration. The dehydrated cake was placed in a sealable container made of vinyl fluoride resin, Tetravac (trademark, manufactured by DuPont), sealed, and air was pumped into the headspace above the cake at regular intervals to purge it. The methyl mercaptan concentration of the odor was measured. The results are shown in Table 1.

Table 1 Also, the concentrations of methyl mercaptan and hydrogen sulfide in the upper part of the mud supply section to the furnace fabric of the belt press dehydrator were measured. The results are shown in Table 2.

As can be seen from Table 2 and Table 1, the dehydrated cake to which the sludge deodorizer was added suppressed the odor generation even after 17 hours, whereas the odor of the cake without the additive was immediately released. Occur. Table 2 also shows that the sludge deodorizer also improves the working environment in the sludge dewatering process.

[Example 2] Looomg/Q of the chemicals shown in Table 3 were added to a mixture of sewage primary sedimentation tank sludge and activated sludge surplus sludge, and Example 1
The dehydrated cake was dehydrated in the same manner as above, 100 g of the dehydrated cake was placed in a Tetravac, sealed with nitrogen gas and left at 35°C for 2 days, after which the generated methyl mercaptan and hydrogen sulfide were measured.

The results are also shown in Table 3. For comparison purposes.

In addition to the sludge deodorizer of the present invention, cases in which commercially available industrial disinfectants and the like are added to sludge are also described.

(The following is a blank space) From Table 3, it can be seen that the sludge deodorizer of the present invention exhibits an excellent deodorizing effect compared to other commercially available industrial disinfectants.

〔effect〕

The sludge deodorizer of the present invention can directly act on putrefactive bacteria and sulfate-reducing bacteria that decompose organic matter anaerobically and generate odors, suppressing their activity and cutting off the generation of bad odors at the source6. When sludge is dehydrated, odor generation from the dehydrated cake can also be suppressed.

Patent applicant: Tokyo Sewerage Service Co., Ltd. and one other representative Patent attorney Sa 1) Morio 6, Contents of amendment Procedures Amendment document 1988 Patent Application No. 41200 2 Title of invention Sludge deodorant 3, Amendment Relationship with the case of the person who did the patent application: 2-6-2 Otemachi, Chiyoda-ku, Tokyo, Tokyo Sewerage Service Co., Ltd. (one other person) Representative: Between
Hiroshi Kata 4, Agent 4-5 Kojimachi, Chiyoda-ku, Tokyo (102) (I) Next to "■/Q is sufficient" on page 6, line 8 of the specification, "
It can be added at any point in the sludge treatment system from before the coagulation treatment process to after the dewatering process. It may be added before, after, or simultaneously with the addition of the flocculant used in the flocculation step. It may be added after being mixed with a flocculant in advance. Furthermore, if the coagulation and dehydration equipment is sealed and there is no risk of odor diffusion during the coagulation treatment process or dehydration process, it may be added to and mixed with the dehydrated cake after dehydration. ” to join.

(2) “■” in Table 1 on page 7 and Table 2 on page 8 of the specification
/QJ is corrected as rPPmJ.

that's all

Claims (1)

[Claims] 1. A sludge deodorizer containing an isothiazolone compound represented by the following general formula (I) or a salt thereof as an active ingredient. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R_1 is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, R_2 and R_3 are a hydrogen atom, a halogen atom, or an alkyl group having 1 to 4 carbon atoms. 2. The sludge quencher according to claim 1, wherein the isothiazolone compound represented by the general formula (I) is 1,2-benziisothiazolone. Odorant.