JP2002059105A - Method of preventing emission of odor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of preventing the emission of a noxious gas from the surface of reclaimed site, for which an effective countermeasure is not presently taken, particularly the emission from the slope, which fails to notice. SOLUTION: The emission of the noxious gas is prevented by preparing water slurry from powdery activated carbon having excellent gas adsorptive property, powdery slaked lime having the ability to neutralize an acidic gas and a binder for giving adhesiveness to soil and spraying or blowing the water slurry to the surface and slope of the reclaimed site.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for neutralizing odors generated from waste landfills by powdered activated carbon and powdered slaked lime.
The present invention relates to a method for preventing the emission of odor by adsorption.

[0002]

2. Description of the Related Art In many cases, leaching of contaminated water and generation of harmful gas are found in landfills of wastes, which is a major social problem. Regarding the treatment of contaminated water leached out, there have been cases where exclusion measures have been taken by chemical treatment or adsorption treatment with activated carbon, and patents have been filed.

However, there are few cases in which effective measures are taken to prevent the emission of harmful gas generated. In most cases, waste is compressed with a bulldozer and the surface is covered with earth and sand. As the height of the landfill increases, harmful gas is emitted from the slope. No patent has been filed for a method for preventing the emission of harmful gas generated from this surface or slope.

[0004]

At present, no effective measures have been taken to prevent the emission of harmful gas generated from the surface of a waste landfill. Therefore, a method for preventing the emission of harmful gas from the surface by using activated carbon and slaked lime, particularly to prevent the emission from the overlooked slope is provided.

[0005]

Means for Solving the Problems A powdery activated carbon having excellent gas adsorption, a powdered slaked lime having an ability to neutralize acidic gas and a binder for imparting adhesion to soil are made into a water slurry to be applied to the surface and slope of a landfill. Provided is a method of preventing harmful gas from being emitted by spraying or spraying.

It is well known that slaked lime reacts with hydrochloric acid gas, sulfur compound gas and the like to neutralize it. It is well known that this principle is used for flue gas desulfurization and neutralization of flue gas in incinerators. Powdered slaked lime is generally sold for these purposes.

It is well known that activated carbon efficiently adsorbs organic gas. Since general activated carbon is hydrophobic, it is excellent in adsorbing organic gas. Activated carbon contains alkaline ash and is therefore suitable for absorbing acidic gas. Powdered activated carbon is used in large quantities at the water purification plant when moldy odor is generated. Activated carbon powder is blown into flue gas together with slaked lime to catch dioxins generated from a medium-sized incinerator, and is used in a process where it is caught by a bag filter. The particle size of the activated carbon is 100 mesh pass.

In the experiment, 4G-H powder from Kuraray Chemical Co., Ltd. was used. The equilibrium adsorption amount Xi of 4 G-H ammonia and hydrogen sulfide as an acidic gas is represented by the following equation. Xi = A
・ CiB. A is a constant, B is a constant and a power. A of ammonia is 8.3 and A of hydrogen sulfide is 34.0. B of ammonia is 0.063 and B of hydrogen sulfide is 0.126. Ci is the gas concentration at that time. Gas concentration 10ppm
The equilibrium adsorption amount (adsorption amount g per 100 g of activated carbon) of the two is as follows. Ammonia 9.6. Hydrogen sulfide 45.4. Large adsorption amount of hydrogen sulfide.

The color tone of slaked lime is pure white, while the color tone of activated carbon is pure black. Neutralizing power and adsorption performance are not related to the color tone, but there are some cases where care must be taken when spraying in prominent areas. The blend ratio and color tone of activated carbon and slaked lime were compared visually. When activated carbon: slaked lime = 10: 90, the color is gray and there is no discomfort. 20:80 is the limit that is not black. Of course, the apparent color changes in any way depending on the amount sprayed on the landfill surface. Even with 100% activated carbon, there is no discomfort in color tone if the amount of application is small. Generally speaking, activated carbon: slaked lime = 95: 5 to 5:95 is an easy-to-use ratio.

Spraying a mixed slurry of activated carbon and slaked lime can neutralize and adsorb organic gas and acidic gas, but depending on the surface condition of the landfill, the activated carbon may soar by the wind. To prevent this, it is effective to add a small amount of binder. It is preferable to add 1 to 5% to the total amount of activated carbon and slaked lime. Various binders can be used, but PVA, CMC and various emulsions are preferred. However, in consideration of safety, it is preferable to use a binder that does not contain a component that may cause secondary pollution later.

The method of spraying a water slurry comprising activated carbon, slaked lime and a binder does not require any special technique. It is necessary to stir the slurry so that the solid matter does not settle. When activated carbon is used, it is necessary to take measures to prevent the occurrence of secondary pollution since dust is formed when it is dry. Use of a wet product can prevent dust generation but increases costs.
You can choose wet or dry depending on the location and cost of spraying.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS It is important to conduct a site survey when the present invention is to be effectively implemented on site. It is important to grasp the location conditions of the site and to determine whether it is close to a private house, flat ground or mountainous land. It is important to investigate the generated gas and pH of soil.

For the purpose of gas investigation, there are a method of directly sampling a gas and measuring it by GCMS, and a method of putting earth and sand in a flask and heating it and measuring the gas emitted by GCMS. On the other hand, pH can be known by stirring earth and sand with water in a flask and measuring the pH of the aqueous phase.

By grasping the site, a more effective spraying method can be determined. Determine the mixing ratio of activated carbon and slaked lime, the addition ratio of binder, and the amount of spray per unit surface area.

[0015]

[Example] Industrial waste is landfilled (stacked) for about 3000 square meters on a hill at the foot of a mountain for 6 years. After the waste is compacted with a bulldozer, the surface is covered with earth and sand. The height was about 10 meters, and miscellaneous waste was exposed from the slope. A complaint was made by the residents that the odor was emitted, and the site was investigated.

Although the surface was covered with earth and sand, no terrible odor was felt, but from the slope, an off-flavor and a pungent sulfur odor were felt. The pH of the surface sand was 6.0. Hydrogen sulfide and mercaptan were detected by GC analysis. 700k water
g, 240 kg of powdered slaked lime, 60 kg of powdered activated carbon, and 9 kg of an acrylate emulsion were mixed and sprayed on the surface and the slope with a slurry pump. The amount of application was 1 kg of solid content per square meter. One month after spraying, a bad smell is not felt. The odor complaint has gone.

According to the present invention, a slurry composed of powdered activated carbon, powdered slaked lime and an emulsion is sprayed on the surface and slope of an industrial waste landfill where the pH of the surface soil is 6.0 and hydrogen sulfide and mercaptan are generated. The emission of gas was prevented.

Claims (4)

[Claims] 1. Spraying or spraying a water slurry obtained by adding a binder to a mixture of powdered activated carbon and powdered slaked lime on the surface of an odor-producing ground to reduce the emission of odors generated from waste landfill sites. How to prevent. 2. The mixing ratio of activated carbon and slaked lime is 95: 5.
The method according to claim 1, wherein the ratio is from 5 to 95. 3. The method for preventing odor emission according to claim 1, wherein the addition ratio of the binder to the total solid content of the activated carbon and the slaked lime is 1 to 5%. 4. The method according to claim 1, wherein the binder is PVA, CMC, or an emulsion.