JP4513935B2 - Deodorization method - Google Patents

Description

【００２４】
【発明の効果】
本発明によれば、少ない薬注量で脱水汚泥ケーキの硫化水素、メルカプタン類を効果的に抑制させることができる。
【図面の簡単な説明】
【図１】 汚泥脱水工程
【符号の説明】
１：ベルトプレス濾布
２：脱水汚泥ケーキ搬送用ベルトコンベア
３：脱水汚泥ケーキスクレーパー
４：汚泥貯留槽引き抜きポンプ吐出部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for deodorizing a sludge cake. Specifically, this is a method of effectively suppressing the odor generated by the sludge cake with a small amount of chemical.
[0002]
[Prior art]
Dehydrated sludge cake generated in the process of treating industrial wastewater from sewage treatment processes, human waste treatment processes, and various factories has been reused for landfills, incineration, and recently brick, cement, compost, etc. . However, odors such as hydrogen sulfide and mercaptans generated from the dehydrated sludge cake during transportation and storage have become a problem for the working environment and local residents when the dehydrated sludge cake is disposed and reused.
[0003]
Conventionally, these odors have been sucked into activated carbon or biological treatments, given different odors with a masking agent, etc., or deodorized by piping before dehydrating sludge to suppress odors. However, activated carbon and biological treatment by sucking odor requires equipment and maintenance costs, and is not a countermeasure for transportation and work. Treatment with a masking agent does not eliminate the original odor, so it is not a fundamental measure. In the method of adding a deodorant before dehydration, a large amount of deodorant is required for the odor.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a method for suppressing hydrogen sulfide and mercaptans generated from a dehydrated sludge cake with a small amount of deodorant and a simple method.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to solve these problems, the present inventors can effectively suppress hydrogen sulfide and mercaptans by adding a chemical to a specific place in the sludge dehydration step, and further suppress the effect. And the present invention has been reached.
[0006]
That is, the present invention provides (1) peroxide, (2) nitrate ion or nitrite ion, (3) peroxide and nitrate ion, (4) peroxide and nitrite ion, or (5) In a method for deodorizing by adding a chemical comprising peroxide, nitrate ions and nitrite ions, the chemical is placed on a filter cloth of a belt press of a dehydrator, a cake scraper part, a cake discharge part, and a cake transport belt conveyor It is related with the deodorizing method characterized by adding to the top or in a hopper.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The dewatered sludge cake treated in the present invention includes dehydrated sludge cake generated in the process of treating industrial wastewater from a sewage treatment plant, human waste treatment plant or various factories.
[0008]
In the present invention, peroxide, nitrate ion, nitrite ion, peroxide and nitrate ion, peroxide and nitrite ion, or peroxide, nitrate ion and nitrite ion are added to the sludge in the dehydration step. The place to add here is on the filter cloth of the belt press of a dehydrator, the cake scraper part, the cake discharge part, the belt conveyor transported from the cake dehydrator to the hopper, and in the hopper. When adding on the filter cloth of the belt press of a dehydrator, it is desirable to add after natural dehydration.
[0009]
The peroxide of the present invention is hydrogen peroxide, sodium percarbonate, sodium perborate, peracetic acid, or other inorganic or organic peroxides, preferably hydrogen peroxide. Peroxides can be used alone or in several mixtures. The amount of peroxide used is 1 to 2000 ppm, preferably 10 to 1000 ppm, based on sludge or dehydrated sludge cake.
[0010]
Examples of the nitrate ion and / or nitrite ion of the present invention include nitric acid, nitrous acid, or a sodium salt, calcium salt, potassium salt, zinc salt and ammonium salt thereof. Nitrate ions and nitrite ions can be used alone or in a mixture. The amount of nitrate ion and nitrite ion used is 1 to 2000 ppm, preferably 10 to 1000 ppm, based on sludge or dehydrated sludge cake.
[0011]
Peroxide and nitrate ions, or peroxide and nitrite ions may be added simultaneously or sequentially. Moreover, you may add what was mixed beforehand. When mixing in advance, chelating agents such as organic aminosulfonic acid, organic phosphonic acid, and organic carboxylic acid can be added as a stabilizer.
[0012]
As for the addition method, the drug may be added with a metering pump, or it may be added in finer particles by sending a gas such as air obtained from an air compressor or an instrument line simultaneously with the drug. During the addition, a shower nozzle or a spray nozzle may be used. At this time, it is desirable to add the drug with a finer particle diameter of 1000 μm or less.
[0013]
【Example】
The present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples. In each example and comparative example, the hydrogen sulfide and methyl mercaptan concentrations in the hopper storing the dehydrated sludge cake were measured over time.
[0014]
Reference example 1
In the sludge dewatering step of FIG. 1, 200 ppm of hydrogen peroxide was sprayed from the filter cloth (1) of the belt press. The results are shown in Table 1.
[0015]
Reference example 2
In the sludge dewatering step in FIG. 2, 300 ppm of sodium nitrate was sprayed from the filter cloth (1) of the belt press. The results are shown in Table 1.
[0016]
Example 1
In the sludge dewatering step of FIG. 1, 100 ppm of hydrogen peroxide and 300 ppm of sodium nitrate were sprayed from the filter cloth (1) of the belt press. The results are shown in Table 1.
[0017]
Reference example 3
In the sludge dewatering step of FIG. 1, 200 ppm of hydrogen peroxide was sprayed from the belt conveyor (2) for transporting the dewatered sludge cake. The results are shown in Table 1.
[0018]
Reference example 4
In the sludge dewatering step of FIG. 1, 400 ppm of sodium nitrate was sprayed from the dewatered sludge cake transport belt conveyor (2). The results are shown in Table 1.
[0019]
Example 2
In the sludge dewatering step of FIG. 1, 100 ppm of hydrogen peroxide and 100 ppm of sodium nitrate were sprayed from the belt conveyor (2) for transporting the dewatered sludge cake. The results are shown in Table 1.
[0020]
Example 3
In the sludge dewatering step of FIG. 1, 100 ppm of hydrogen peroxide and 100 ppm of sodium nitrate were sprayed on the dewatered sludge cake scraper part (3). The results are shown in Table 1.
[0021]
Comparative Example 1
In the sludge dewatering step of FIG. 1, no chemical was added. The results are shown in Table 1.
[0022]
Comparative Example 2
In the sludge dewatering step of FIG. 1, 100 ppm of hydrogen peroxide and 100 ppm of sodium nitrate were line-injected into the sludge storage tank extraction pump discharge part (4) before dewatering. The results are shown in Table 1.
[0023]
[Table 1]

[0024]
【The invention's effect】
According to the present invention, hydrogen sulfide and mercaptans in a dehydrated sludge cake can be effectively suppressed with a small amount of chemical injection.
[Brief description of the drawings]
[Figure 1] Sludge dehydration process [Explanation of symbols]
1: belt press filter cloth 2: dehydrated sludge cake conveyor belt conveyor 3: dehydrated sludge cake scraper 4: sludge storage tank pulling pump discharge unit

Claims (2)

In the sludge dehydration process, ( A ) hydrogen peroxide and nitrate ions, ( B ) hydrogen peroxide and nitrite ions, or ( C ) hydrogen peroxide , nitrate ions and nitrite ions are added to deodorize them. In the method, the deodorizing method is characterized in that the chemical is added onto a filter cloth of a belt press of a dehydrator, a cake scraper section, a cake discharge section, a cake transport belt conveyor, or a hopper.   The deodorizing method according to claim 1, wherein the chemical is sprayed onto the dehydrated sludge cake with a particle size of 1000 μm or less.

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