JP2015073981A - Disposal method of burned residue - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem of conventional techniques and to provide a disposal method of a burned residue where: intermediate soil covering and the like are omitted; the treatment cost of a leachate is suppressed; a disposal field can be used at an early stage; there is no risk of settlement in future; and landfill disposal can be performed with working efficiency not inferior to conventional methods.SOLUTION: A disposal method of a burned residue comprises: a kneaded object formation step; a layered body formation step; a plastic fluid layer formation step; and a solidified board formation step. In the plastic fluid layer formation step, cement and water are permeated around the particles of the burned residue by applying surface vibration to the surface of a layered body where a non-flowable plastic kneaded object kneaded by the addition of the cement and water to the burned residue is layered and then a plastic fluid layer with flowability is formed. The burned residue is disposed by stacking two or more solidified boards due to the repeat of the steps. The plastic kneaded object in a subsequent step is directly placed and spread on the solidified board and the upper layer and the lower layer of the solidified boards are continuously formed.

Description

  The present invention relates to disposal of waste incineration residues. More specifically, the present invention relates to an incineration residue disposal method in which cement and water are added to solidify the incineration residue and then landfilled.

  In recent years, the amount of waste in Japan has been declining due to various efforts centered on the national and local governments. Still, over 400 million tons of waste is discharged annually, and securing a disposal site is still a big problem. Looking at the breakdown of waste, general waste is about 45 million tons and industrial waste is about 390 million tons, and industrial waste accounts for nearly 90% of the total.

  Industrial waste and general waste are broadly classified into those to be recycled and those to be disposed of, and those to be disposed are further classified into those that are incinerated and those that are not. For example, in the case of general waste, the waste to be disposed of is divided into those that are sent directly to the incineration facility and those that are sent to the intermediate treatment facility. Of the processing residues generated at the intermediate treatment facility, those that are incinerated are newly incinerated. Sent to. And the thing which is not incinerated among the processing residues produced in the intermediate treatment facility and the incineration residue produced in the incineration facility are sent to the final disposal site.

  General waste landfilled at the final disposal site is approximately 5 million tons per year, of which approximately 3.5 million tons of incineration residues, 70% of which is occupied by incineration residues. On the other hand, of industrial waste, about 8 million tons are incineration residue out of about 14 million tons disposed annually at the final disposal site, and more than half is also incineration residue. In this way, the current final disposal site looks like an “ash dumping site”.

  Incineration residue is classified into main ash and fly ash. The main ash (bottom ash) is collected at the bottom of the furnace of the incineration facility, and the one collected by the dust collector or attached to the boiler is fly ash (fly ash). Fly ash is discharged only about 1/3 of the main ash, but contains more dioxins, heavy metals such as lead, zinc and cadmium than the main ash. Therefore, before the incineration residue is landfilled at the final disposal site, the liquid chelating agent is added to the fly ash. The chemical bond with the liquid chelating agent makes it difficult for heavy metal ions in fly ash to elute into the environment.

  Incineration residue of general waste is often landfilled at a general waste final disposal site, and industrial waste is often landfilled at a managed final disposal site. General waste final disposal sites are also classified as “managed” final disposal sites, and this managed final disposal site is maintained so that the leachate from the disposal site and the surrounding groundwater meet the standards specified by the Ministerial Ordinance. Must be managed. Furthermore, in order to abolish the management-type final disposal site, it is necessary to recognize that the water quality collected in the site conforms to the specified drainage standards for over two years. Therefore, in the management-type final disposal site, incineration residue or the like is not directly buried on the natural ground, but as shown in Fig. 5, a water shielding sheet is laid on the natural ground and a protective layer (sand or earth and sand) is installed. In addition, incineration residue etc. are reclaimed.

  However, even if measures such as those shown in Fig. 5 are taken, it does not necessarily meet the ministerial ordinance standards, and the amount of leachate from the disposal site is stored to some extent and is discharged after being treated with water. is there. In other words, many management-type final disposal sites are difficult to maintain, and it is said that it will take 20 to 30 years to abolish them, and they must be operated as final disposal sites for an extremely long period. Therefore, costs for maintenance such as discharge treatment of leachate are increased, and a considerable period of time is required until the site is used as a site.

  In addition, there is another problem in terms of site use. As already mentioned, most of the landfill disposal at the managed final disposal site is incineration residue. Incineration residue is an inorganic substance, and it is unlikely that gas such as carbon dioxide is generated, but in reality, there are some incineration residues that remain unburned, which may cause gas generation. Normally, gas generation occurs over a long period of time. For example, if gas is generated after using the site of the final disposal site, the site will sink as much as that occurs, and facilities and structures built on the site of the site Will be affected.

  Furthermore, the conventional managed final disposal site also has a problem in terms of space utilization of the disposal site. The incineration residue transported to the managed final disposal site is spread, for example, in a 50 cm layer and rolled by a heavy machine such as a bulldozer. As described above, since the fly ash is treated with the addition of the liquid chelating agent, it initially has a certain degree of moisture, but if it is then dried, the fly ash is likely to be scattered. Therefore, it is necessary to take measures to prevent scattering, and as shown in FIGS. 5 and 6, intermediate cover soil is installed on the incineration residue after rolling. Since the intermediate covering soil is installed on the incineration residue stacked 5 to 6 layers, a period in which the incineration residue is exposed occurs. Therefore, in recent years, the same-day covering (daily cover) that covers the soil after daily landfill work has become the mainstream.

The installation of intermediate and same-day soil means that the incineration residue cannot be landfilled. The remaining capacity of final disposal sites in the Tokyo metropolitan area is a not trivial 15 million m ^3, so that the remaining number of years is said to be four years, space ensure the disposal site is a very important issue. Therefore, there was a need for a disposal method that could omit intermediate cover and same day cover.

  Therefore, Patent Document 1 proposes a method of solidifying and disposing of inorganic waste such as incineration residue. Specifically, inorganic waste is divided into low-density waste and high-density waste, and water and cement are mixed to make two types of kneaded materials. Then, one kneaded product is placed in a mold and the other is placed in a different place and then solidified. According to this method, since the lump containing the incineration residue is solidified, it is possible to suppress leachate and prevent future settlement of the disposal site without requiring intermediate covering soil for preventing scattering or same-day covering soil.

  By the way, when a certain substance is solidified with a cement-type solidifying material, various problems may occur depending on the formulation. For example, when the amount of water is increased to improve workability, there is a problem in that breathing occurs and cracks associated therewith occur. In addition, when the amount of cement is increased to improve the strength, there is a problem in that internal restraint is accompanied by an increase in heat of hydration and so-called temperature cracking occurs.

  So far, the applicant of the present application has proposed a “superfluid construction method” which is a suitable technique for solving the above-described problems that occur when an object is solidified with a cement-based solidifying material. For example, patent document 2 knead | mixes cement, coal ash, and water (about an optimal water content ratio), produces | generates a kneaded material, conveys this kneaded material to a construction site, and adds a vibration to a kneaded material at the conveyed tip. A method has been proposed in which it is placed in a fluidized state and placed at a predetermined location. According to this technique, the kneaded material is simply kept in a wet powder state, so that the kneaded material hardly adheres to the conveying means and kneading means for handling the kneaded material. As a result, the conveying means and the kneading means can be easily cleaned and the material can be used without waste.

JP 2010-207669 A Japanese Patent Laid-Open No. 10-311142

  Although the method of Patent Document 1 has several effects, it requires a formwork for placing the kneaded material, a temporary dam weight for holding the formwork, and the space for installing these. Is also required. Therefore, the amount of disposal that can be filled at one time is limited, and the work efficiency is significantly inferior compared with the conventional method of simply rolling the bulldozer, which requires assembly of the formwork and other temporary work. It will be.

  The subject of the present invention is to solve the problems of the prior art, i.e., omitting the intermediate cover, etc., suppressing the treatment cost of leachate, can use the disposal site at an early stage, there is no risk of sinking in the future, In addition, an incineration residue disposal method capable of landfilling the incineration residue with work efficiency not inferior to the conventional method is provided.

  The present invention was made by paying attention to the disposal of incineration residues by applying the superfluid method developed by the applicant, and by making water and cement permeate between the particles of the incineration residue, it is more precise. This was based on an unprecedented idea of forming a solidified board.

  The incineration residue disposal method of the present invention is a method including a kneaded product forming step, a layered body forming step, a plastic fluid layer forming step, and a solidifying disc forming step. The kneaded product forming step is a step of forming a non-flowable plastic kneaded product by adding cement and water to the incineration residue and kneading. The layered body forming step is a step of forming a layered body of the plastic kneaded material by spreading the plastic kneaded material in layers at a predetermined position of the disposal site. The plastic fluid layer forming step is a step of forming a fluid plastic fluid layer by infiltrating cement and water around the particles of the incineration residue by applying surface vibration to the surface of the layered body. The solidifying disk forming step is a step of forming a solidifying disk by waiting for a predetermined time and solidifying the plastic fluid layer. By repeating the above steps, two or more solidification boards are stacked, and the incineration residue is disposed of. Note that the plastic kneaded material in the subsequent process is directly spread on an existing solidification board, and the upper and lower solidification boards are formed continuously.

  The incineration residue disposal method of the present invention can also be a method of forming a solidification board composed of divided solidification boards divided into two or more planes. In the layered body forming step in this case, a divided layered body is formed in a range corresponding to the divided solidified disk, and the divided layered body is formed as a side surface with inclined side surfaces (side surfaces in contact with the divided solidified disk formed in the subsequent process). It is formed. In the plastic fluid layer forming step, the divided plastic fluid layer is formed by applying surface vibration to the upper surface and the inclined side surface of the divided layered body. In the solidifying plate forming step, the divided solidified plate including the inclined side surface is formed. Form. The divided plastic kneaded material in the subsequent process adjacent to the existing divided solidification board is spread and placed so as to contact the inclined side surface of the existing divided solidification board. Thus, one layer of solidification disk is formed by two or more continuous divided solidification disks.

  The incineration residue disposal method of the present invention may be a method further including a carry-in process. The carrying-in process is a process of carrying in the incineration residue into the disposal site. In this case, the kneaded product forming step is performed in the disposal site.

The incineration residue disposal method of the present invention has the following effects.
(1) The state in which cement and water are added to the incineration residue and kneaded is generally a non-fluid state of slump 0 cm, but by imparting surface vibration to this, the fluidity is increased and an extremely dense solidified body is obtained. . Specifically, since a solidified board having a water permeability coefficient of 10 ⁻⁷ to 10 ⁻⁹ (cm / s) is formed, it is possible to eliminate permeated water from the outside such as rain water, and it is derived from heavy metals etc. in the incineration residue Leaching of harmful substances can be suppressed. As a result, the treatment cost for the unit leachate is drastically reduced, and the leachate itself is greatly reduced, so that the overall leachate treatment cost is significantly reduced.
(2) As described above, a solidification board having a hydraulic conductivity of 10 ⁻⁷ to 10 ⁻⁹ (cm / s) order is formed, and leaching of harmful substances in the incineration residue can be suppressed. The disposal site can be abolished and used as a site in an extremely short period of time (approximately 2.5 years).
(3) Since the incineration residue contains a small amount of organic substances and contains a large amount of silicon and alumina, a stable crystal (solidified) is generated by the hydration reaction of water and cement. Therefore, the subsidence phenomenon accompanying the generation of gas such as carbon dioxide does not occur, and the ruins can be used with confidence at an early stage.
(4) Since incineration residue is landfilled while forming a stable solidification board, no intermediate or same-day soil covering is required to prevent the incineration residue from scattering. As a result, a large amount of incineration residue corresponding to the intermediate covering and the same day covering can be landfilled. In the case of the present invention, it is necessary to mix cement, but as a result of trial calculation, it has been found that even if the amount of cement used is subtracted, the disposal amount is still improved by about 15%.
(5) Since the side surface of the divided plastic fluid layer can be self-supporting, it is not necessary to use a mold, and as a result, the landfill operation can be performed with an efficiency equal to or higher than that of the conventional method.
(6) The incineration residue will be solidified ground by stacking the solidified landfill. Since this solidified ground is a rigid body, it can be more resistant to earthquakes than conventional disposal sites. In addition, as described above, rainwater and the like hardly penetrate into the solidified ground, and as a result, it is difficult to form a slip surface or a collapsed surface in the solidified ground. There is nothing to do.

Explanatory drawing which shows a series of flows of the incineration residue disposal method of this invention. The flowchart which shows a series of flows of the incineration residue disposal method of this invention. The fragmentary sectional view which shows the process in which the layered body of plastic kneaded material is formed. Explanatory drawing which shows the condition which forms a plastic fluid layer. The fragmentary sectional view which shows the structure of the conventional management type final disposal site. The fragmentary sectional view explaining the intermediate | middle cover soil in the conventional management type final disposal site.

  An example of an embodiment of the incineration residue disposal method of the present invention will be described with reference to the drawings.

1. Overall Overview FIG. 1 is an explanatory diagram showing a series of flows of the incineration residue disposal method of the present invention. With reference to this figure, the general outline of the present invention will be described first. First, an incineration residue containing fly ash is carried into a final disposal site by a transport vehicle such as a sealed dump truck Dt, and is dropped at a predetermined location (A in FIG. 1). Appropriate amounts of water and cement are added to the incineration residue and kneaded with a stabilizer or a backhoe Bh (B in FIG. 1). At this time, it can also knead | mix by the mixing plant prepared separately. What is obtained as a result of kneading incineration residue, an appropriate amount of water and cement is a “non-flowable plastic kneaded product” having a slump of about 0 cm. Next, the non-flowable plastic kneaded material is spread in layers by a heavy machine such as a backhoe Bh to form a “layered body of plastic kneaded material” (C in FIG. 1).

  When the layered body of the plastic kneaded material is formed, surface vibration is applied from the surface of the layered body by the vibration plate Vb attached to the backhoe Bh or the like (D in FIG. 1). When vibration is applied to a non-flowable plastic kneaded product, cement and water permeate around the particles of the incineration residue (between particles), and the layered body of the plastic kneaded product is fluidized by vibration for about 30 to 60 seconds. , A “fluid plastic fluid layer” is formed. When waiting (curing) in this state, after about one day, a “solidification board” is formed in which the fluid plastic fluid layer is solidified. These steps (A to D in FIG. 1) are repeated to stack a plurality of solidification boards, and the incineration residue is landfilled.

  Hereinafter, according to the flowchart shown in FIG. 2, it demonstrates in detail for every main element which comprises the incineration residue disposal method of this invention.

2. Protection Work First, in order to accept the incineration residue as a final disposal site, as shown in FIG. 5, a water shielding sheet is laid on the excavated and shaped natural ground (Step 10). After laying the water-impervious sheet, a protective layer using sand or earth and sand is installed from above (Step 20), and acceptance of the incineration residue is started.

3. As described above, the incineration residue of general waste and industrial waste generated in incineration facilities etc. is carried to the final disposal site by a transport vehicle such as a sealed dump truck Dt and placed at a predetermined position in the disposal site. It is lowered (Step 30).

4). Kneaded product forming step Water and cement are added to the incineration residue and kneaded (stirring to mixing) with a predetermined machine (or human power) (Step 40). This incineration residue contains fly ash, and in order to obtain a superfluid state, which will be described later, it is desirable to contain more than half of the fly ash (that is, fly ash: main ash = 50: 50). The amount of cement to be added is small with respect to the incineration residue. For example, the weight ratio between the incineration residue and the cement can be 95: 5 to 80:20. Moreover, it mix | blends so that water cement ratio (W / C) may become as small as possible, and a suitable quantity of water is added with respect to cement amount. In addition, various cements such as Portland cement, blast furnace cement, fly ash cement, silica cement, alumina cement, and other cement-based solidifying materials can be adopted as the cement added here.

The reason for reducing the water-cement ratio by adding only an appropriate amount of water is to solidify the kneaded material densely by surface vibration given in the subsequent process, and as a result, to obtain a small water permeability coefficient. Here, “appropriate amount” of water will be described. As will be described later, in order to obtain a hydraulic conductivity of the order of 10 ⁻⁷ to 10 ⁻⁹ (cm / s), it is necessary to make the particle arrangement of the incineration residue uniform and solid. In addition, the kneaded product must be liquefied. However, if excessive water is added, the plastic state cannot be maintained and handling of the kneaded product becomes difficult, and due to the problem of breathing, an appropriate strength is not expressed and a desired water permeability cannot be obtained. Further, sufficient liquefaction cannot be expected with a small amount of water, and temperature cracking may occur. Therefore, an appropriate amount of water is required, and as a method for determining the appropriate amount, a method based on the optimal water content ratio can be exemplified. As a value representing the degree of compaction, the dry unit volume weight (dry density) is generally used. As this value is increased, the strength is increased, the degree of compaction is improved, and the water permeability coefficient is decreased. Even under the same compaction conditions, the dry unit volume weight obtained differs depending on the amount of water contained, and the water content ratio that gives the largest dry unit volume weight is the “optimum water content ratio”. It should be noted that the amount of water slightly increased from the optimum water content ratio of the kneaded material is preferably determined as “appropriate amount of water” because a large amount may be compacted on site.

  What is obtained in this kneading step is a non-flowable “plastic kneaded product”. The non-flowable plastic kneaded material is in a so-called zero slump state in a moist soil state. Compared to the “fluid plastic fluid layer” described later, the fluidity of the plastic kneaded product obtained here is extremely small.

5. Layered body forming step When a plastic kneaded material can be formed, it is spread and layered using a heavy machine such as a backhoe Bh to form a "layered body of plastic kneaded material" (Step 50). FIG. 3 is a partial cross-sectional view showing a process of forming a layered body of a plastic kneaded product. The layered body of the plastic kneaded material is a layer that is spread over the entire surface of the disposal site with an equal thickness of, for example, about 50 cm. Usually, the area of the disposal site is vast, that is, the layered body of the plastic kneaded material also has a large area. Therefore, although it depends on the amount of incineration residue to be carried in and the leveling capacity, it is usually not necessary to finish all the layers in a single day, but in many cases it is divided and finished in plane. . For the sake of convenience, the layered body of the plastic kneaded product divided into planes is referred to herein as “divided layered body 10”, and the solidified body is referred to as “divided solidification board 20”.

  When the layered body is formed by dividing, an independent side surface 10a that does not contact the other divided solidification board 20 or the protective layer (natural ground) is temporarily formed as shown in FIG. The independent side surface 10a is a side surface 10a in contact with the divided layered body 10 (shown by a broken line in the drawing) formed in a subsequent process, and is a so-called joining surface. I will do it. If the material to be reclaimed is a fluid, a formwork is required for the joining side surface 10a. However, as described above, the plastic kneaded material is in a zero slump state, and can be self-supported even on a vertical surface. 10a does not require a formwork.

  Although the plastic kneaded material can be self-supporting even on a vertical surface, the joining side surface 10a is inclined as shown in FIG. The reason is to improve the workability of surface vibration performed in the next process. When the joining side surface 10a is self-supporting as a vertical surface, it is somewhat difficult to vibrate surface-wise, and surface vibration becomes easy when the joining side surface 10a is inclined at a predetermined angle. The inclination angle at which surface vibration can be easily applied (the angle formed by the horizontal surface and the joining side surface 10a) varies depending on the properties of the incineration residue, the material to be added, the composition, and the like, but a range of approximately 20 ° to 40 ° can be exemplified. .

6). Plastic Fluid Layer Forming Step When the divided layered body 10 is formed, a “divided plastic fluid layer” is formed (Step 60). FIG. 4 is an explanatory diagram showing a situation in which the divided plastic fluid layer 30 is formed. As shown in this figure, the divided plastic fluid layer 30 is formed by applying surface vibration from the outside to the surface of the divided layered body 10, specifically, the upper surface 10b and the joining side surface 10a. As the means, various conventional ones such as a diaphragm Vb attached to a heavy machine such as a backhoe Bh can be adopted. For example, at a frequency of 3,000 to 5,000 rpm and an amplitude of 0.5 to 2.0 mm. Can be vibrated.

By applying surface vibration to the plastic kneaded material, the divided layered body 10 is changed from a non-fluid state to a fluid state (superfluid state). Incineration residues such as those containing a relatively large amount of spherical particles can be easily separated from each other by virtue of the bearing effect of the spherical particles contained in the particles when vibration is applied. Go around evenly. The plastic kneaded material loses effective stress and causes only a pore water pressure to cause a liquefaction phenomenon. A liquefied plastic kneaded product is a divided plastic fluid layer 30 (superfluid layer), which changes to a pudding-like layer. The divided plastic fluid layer 30 has a uniform and solid particle arrangement due to liquefaction, and the incineration residue contains a small amount of organic substances and a large amount of silicon and alumina, so that water and cement are not mixed. A stable crystal body (solidified body) is generated by the hydration reaction. What solidified in this state has few cracks and high strength, and a water permeability coefficient of the order of 10 ⁻⁷ to 10 ⁻⁹ (cm / s) is obtained.

7). Solidification board formation process When the division plastic fluid layer 30 is formed, it waits until it solidifies (about 1 day) (Step 70). At this time, you may wait without performing anything especially, and you may perform the curing using a sheet | seat etc. FIG. The “division solidification board 20” is obtained as a result of the divisional layered body 10 solidifying. When the divided solidification board 20 is formed, the steps 50 to 70 in FIG. 2 are repeated (loop A) to form the adjacent division solidification board 20 and complete the solidification board 200 (FIG. 3) for one layer. (Step 80).

8). Final Covering Step 50 to Step 80 in FIG. 2 are repeated (Loop B), and the solidification board 200 is stacked up to the planned number of layers (number of layers) to finish the solidification board 200 of all layers (Step 90). At this time, as shown in FIG. 3, the divided layered body 10 is spread directly on the lower solidifying board 200 without being covered with the intermediate covering or the same day covering. Then, when the final (top) solidifying board 200 is formed, it is covered with the final covering (Step 100), and the final disposal site is completed.

  The incineration residue disposal method of the present invention can be particularly effectively implemented at a general waste final disposal site or an industrial waste management final disposal site. The invention of the present application is not only industrially applicable but also socially large, considering that it provides a suitable solution to the squeeze of the remaining capacity of the final disposal site, which is now an urgent issue. It is an invention that can be expected to contribute.

DESCRIPTION OF SYMBOLS 10 Divided layered body 10a Joint side surface 10b Upper surface of divided layered body 20 Divided solidification board 200 Solidification board 30 Divided plastic fluid layer Bh Backhoe Dt (sealed type) dump truck Vb Vibration plate

Claims (3)

In the method of disposing of incineration residue,
A kneaded product forming step of forming a non-flowable plastic kneaded product by adding cement and water to the incineration residue and kneading; and
A layered body forming step of forming a layered body of the plastic kneaded material by spreading the plastic kneaded material in layers at a predetermined position of the disposal site;
A plastic fluid layer forming step of forming a fluid plastic fluid layer by infiltrating cement and water around the particles of the incineration residue by applying surface vibration to the surface of the layered body;
By solidifying the plastic fluid layer waiting for a predetermined time, a solidifying disk forming step for forming a solidified disk, and
The plastic kneaded material of the subsequent process is spread directly on the solidification board to form an upper solidification board, and the incineration residue is disposed by stacking two or more solidification boards in the disposal site. Characterized incineration residue disposal method. The solidification board is composed of a division solidification board divided into two or more planes,
In the layered body forming step, a divided layered body is formed in a range corresponding to the divided solidified disk, and the divided layered body is formed as an inclined side surface in contact with the divided solidified disk formed in a subsequent process,
In the plastic fluid layer forming step, a divided plastic fluid layer is formed by applying surface vibration to the upper surface and the inclined side surface of the divided layered body,
In the solidification board forming step, the divided solidification board including the inclined side surfaces is formed,
The divided plastic kneaded material of the subsequent process is spread and in contact with the inclined side surface of the divided solidifying disk to form an adjacent divided solidified disk, and the solidification of one layer is formed by two or more continuous divided solidified disks. The incineration residue disposal method according to claim 1, wherein a board is formed. A loading step of loading the incineration residue into the disposal site,
The incineration residue disposal method according to claim 1 or 2, wherein the kneaded product forming step is performed in the disposal site.

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