JP3595032B2 - Waste disposal method - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a waste disposal method for finally disposing of waste such as incinerated ash discharged from an incineration plant and unburnable garbage by landfill.
[0002]
[Prior art]
In recent years, the final disposal of waste such as incineration ash discharged from incineration plants, garbage that cannot be incinerated, or especially car scraps has become a major environmental problem not only in Japan but also in the world.
[0003]
Conventionally, most of these wastes have been finally disposed of in a stable waste treatment facility, for example, by being finely crushed by a shredder.
[0004]
[Problems to be solved by the invention]
By the way, since April 1, 1996, so-called non-combustible garbage such as car scraps has been removed from the harmful substances contained in waste due to the revision of the law on waste treatment and cleaning and the waste treatment standards. From the viewpoint of preventing pollution, waste must be uniformly disposed of in a managed waste treatment facility.
[0005]
Therefore, future managed waste treatment facilities are required to have the ability to protect human health or living environment from harmful substances contained in waste over a long period of time.
[0006]
The present invention has been made in view of the above problems, and aims to prevent the spread of contamination by harmful substances from waste for a long period of time while effectively using the limited disposal space of a managed waste treatment facility. The main purpose is to provide a waste disposal method that can be used.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the waste disposal method according to the present invention accommodates individually sealed waste compacts in an enclosed space surrounded by a concrete shielding wall, and prevents air in the enclosed space from being enclosed. After the replacement with the active gas, each pipe for air suction / exhaust and introduction of the inert gas is sealed outside the concrete shielding wall, and embankment is filled on the concrete shielding wall above the closed space.
[0008]
In this case, it is preferable to use a nitrogen gas or a low-temperature gas as the inert gas.
[0009]
Further, in the waste disposal method according to the present invention, when replacing the air inside the closed space with the inert gas, the air is sucked and exhausted from the bottom of the closed space, and nitrogen gas is introduced as the inert gas from the top of the closed space. Then, the replacement operation is terminated based on the increase in the nitrogen concentration of the exhausted air.
[0010]
Moreover, the waste disposal method according to the present invention, after sealing the respective pipes for air suction evacuation and inert gas introduction outside the concrete shield wall after the replacement work, further concrete filling the sealing portions.
[0011]
[Action]
In the waste disposal method according to the present invention, first, the waste is hermetically packaged to prevent direct leakage of harmful substances contained in the waste. When the waste is hermetically packaged, it is hermetically packaged with a packaging material such as a stable plastic material. In this case, if the waste is compression-molded into a certain rectangular shape, and the gas (for example, air) remaining in the package in which the waste is hermetically sealed is suctioned and exhausted, the waste per unit is obtained. The volume of waste can be reduced, and not only can the limited space of the managed waste treatment facility be used effectively, but also the long-term generation of rotting and harmful gas due to oxidation of the hermetically sealed waste itself Can be prevented.
[0012]
Second, by storing the hermetically sealed waste in an enclosed space surrounded by a concrete shielding wall, leakage of harmful substances contained in the waste into the soil is prevented. When storing hermetically sealed waste in an enclosed space, the limited waste of the managed waste treatment facility can be effectively used by laying out and arranging the waste without gaps and storing as much as possible. In addition to the above, the airtightness of the space formed by the concrete shielding wall can be enhanced.
[0013]
Third, by replacing the air present inside the enclosed space surrounded by the concrete shielding wall with an inert gas, for example, even if the hermetically sealed packaging of individual waste is broken, it is present in the waste. It prevents the propagation of microorganisms, the inhabitation of insects and small animals, and the oxidation and corrosion of waste, thereby preventing the leakage and diffusion of harmful substances contained in waste.
[0014]
That is, if air is contained in the enclosed space, microorganisms may propagate by this air, or waste may be oxidized and corroded, and gas may be generated. On the other hand, the waste is hermetically packaged by a packaging material, but it cannot be declared that the packaging material will never be broken, and there is a possibility that the waste will be broken by some influence.
[0015]
Therefore, when the packaging material is broken, the harmful substance diffuses inside the enclosed space, and when cracks or the like occur in the concrete forming the enclosed space, the harmful pollutants may leak from the cracks or the like to the outside. Nature occurs.
[0016]
Therefore, in the present invention, in order to avoid such a situation, the air present inside the closed space is replaced with an inert gas. Therefore, if the air inside the enclosed space is replaced with an inert gas, even if the packaging material of the sealed package of the waste is broken and the waste is exposed, the propagation of microorganisms present in the waste or the penetration of the waste can be achieved. Inhabitation of insects and small animals and oxidation of waste can be prevented, and diffusion and leakage of harmful substances contained in waste can be prevented. As the inert gas, for example, a nitrogen gas, a carbon dioxide gas, or a low-temperature gas thereof can be used.
[0017]
Inert gases are generally stable and do not change over time. In particular, nitrogen gas can be obtained at a low price and does not deteriorate for about 50 to 100 years, so that diffusion of harmful substances from waste can be prevented for a long time.
[0018]
The inert gas obtained on the market is generally in the form of a liquefied low-temperature gas (nitrogen gas has a boiling point of -195.8 ° C. and carbon dioxide gas has a boiling point of -78.5 ° C.). Since the inside of the closed space is cooled by introducing the waste into the closed space, even if heat is generated from the waste by fermentation or the like, it can be removed. In addition, since the inside of the enclosed space is cooled, the growth of microorganisms and the oxidation and corrosion of waste are prevented, and the internal pressure of the enclosed space can be prevented from rising due to these, and cracks occur in the concrete that forms the enclosed space. Can be prevented from occurring.
[0019]
In addition, as a specific method of replacing the air inside the enclosed space with an inert gas, when a nitrogen gas lighter than air is used as the inert gas, the air in the enclosed space is sucked and exhausted from the bottom of the enclosed space, and An inert gas is introduced into the upper part. In this case, the inert gas to be introduced is filled downward from the upper part in the closed space.
[0020]
On the other hand, when carbon dioxide gas heavier than air is used as the inert gas, the inert gas is introduced into the bottom of the closed space while sucking and exhausting air from the upper portion of the closed space. In this case, the inert gas to be introduced is filled upward from the bottom of the closed space.
[0021]
Whether or not the air inside the closed space has been sufficiently replaced with the inert gas can be determined by measuring the concentration of the inert gas in the air exhausted from the closed space. In the present invention, for example, nitrogen gas or carbon dioxide gas is used as the inert gas, and by monitoring the concentration of nitrogen gas or carbon dioxide gas in the exhausted air, these concentrations are more than those in the atmosphere. It can be easily detected whether the inside of the sealed space has been replaced by detecting that the height has become sufficiently high.
[0022]
Fourth, in the present invention, by laying soil on the concrete shielding wall, concrete is prevented from being deteriorated for a long time, and leakage of harmful substances from a closed space is prevented. That is, when the concrete shielding wall is buried in the soil by embankment, it is moisturized by the moisture of the soil, and is not affected by ultraviolet rays due to solar radiation or a temperature change of the outside air, so that cracks and the like hardly occur. Therefore, if the embankment is laid on the concrete shielding wall above the enclosed space, the concrete shielding wall can be kept in a healthy state for a long time, and leakage of harmful substances can be prevented.
[0023]
Preferably, if the concrete shielding wall has an earthquake-resistant structure, even if an earthquake occurs, the occurrence of cracks can be prevented and leakage of harmful substances can be prevented. Further, the upper area of the embankment can be used for various public facilities or fields, including parks, playgrounds, and amusement facilities.
[0024]
Fifth, in the present invention, after replacing the air inside the sealed space with the inert gas, a pipe for sucking and discharging the air inside the sealed space and introducing the inert gas into the inside of the sealed space are provided. By sealing the pipes, and filling the sealed portion with concrete, leakage of harmful substances from the sealed space is prevented.
[0025]
That is, the pipe for sucking and discharging the air inside the enclosed space and the pipe for introducing the inert gas into the enclosed space penetrate the concrete shielding wall forming the enclosed space, and pass through the inside and outside of the concrete shielding wall. Communicating.
[0026]
Therefore, if the gas in the enclosed space leaks from these pipes, or if the outside air is mixed into the enclosed space, the function of the final sealed final disposal is impaired, and the air inside the enclosed space is inerted. After replacement with gas, these pipes are sealed outside the concrete shielding wall, and the sealed portion is filled with concrete. For example, if an open / close valve is installed at the end of the pipe that protrudes outside the concrete shielding wall, close this valve after the replacement work with the inert gas is completed, remove the pipe outside the valve, and include the valve. Wrap the remaining exposed pipe in concrete in a block shape.
[0027]
For example, when sampling the gas inside the closed space at intervals of about once every 5 to 10 years, the concrete block surrounding the pipe end is broken, and the gas inside the closed space is sampled. If the active gas concentration has decreased, the inert gas may be refilled, and then the blocks may be formed by filling with concrete as before. In this case, if the concrete block is covered with the embankment, it is possible to prevent the occurrence of cracks or the like due to the deterioration of the concrete block.
[0028]
As described above, in the present invention, in order to prevent leakage and diffusion of harmful substances generated from waste, single, double, and triple preventive measures are taken, and a request is made to a waste treatment facility for final disposal. It has enough functions to be performed.
[0029]
【Example】
FIG. 1 shows steps of a waste disposal method according to one embodiment of the present invention. In FIG. 1, the steps will be described below assuming that the process proceeds in the order of (a), (b), (c), (d), (e), (f), and (g).
[0030]
In FIG. 1A, for example, waste 3 crushed by a shredder or the like is conveyed by a belt conveyor 2, and is continuously charged into a press device 4 driven by hydraulic pressure. The input waste 3 is compacted by a pressing device 4 to form a rectangular compression molded body (hereinafter referred to as “waste cube”) 5. After that, the waste cube 5 is discharged from the press device 4 and placed on the plastic waterproof sheet 6.
[0031]
Next, as shown in FIG. 1B, the waterproof sheet 6 is folded by an automatic wrapping device or the like (not shown) so as to cover the waste cube 5, and thereafter, as shown in FIG. Opposite edges of the sheet 6 are heat-welded by a heat welding device 7, and the waste cube 5 is hermetically sealed by the waterproof sheet 6 except for a nozzle insertion portion of the vacuum compressor 8 shown in FIG. In addition, the method of hermetic packaging is not limited to the heat welding, and may be bonded by an adhesive.
[0032]
Next, in FIG. 1 (d), the gas inside the package body in which the waste cube 5 is hermetically sealed is sucked and evacuated by the vacuum compressor 8 to make it almost in a vacuum state.
[0033]
This is to prevent a gas (for example, air) remaining inside the package from being generated due to, for example, propagation of microorganisms or corrosion, which may generate gas inside the package.
[0034]
As shown in FIG. 1D, by generating and exhausting the gas inside the package by the vacuum compressor 8, it is possible to avoid the generation of the internal gas after the final disposal.
[0035]
After the inside of the package is almost evacuated by the vacuum compressor 8, the nozzle of the vacuum compressor 8 is pulled out, and then, as described with reference to FIG. It goes without saying that the edge of the waterproof sheet 6 is heat-welded to be completely sealed.
[0036]
Next, in FIG. 1E, the sealed package (see FIG. 1D) is packed with the binding material 9a by an unillustrated automatic packing machine or the like, and the sealed package is made into the packing waste cube 9. .
[0037]
This is because even if the waste is compression-molded and hermetically packaged in a substantially vacuum state, the shape of the package may be broken by handling until it is put into the disposal space by a crane or forklift, etc. This is to prevent this. Therefore, by packing the package with the binding material after the evacuation step, handling can be facilitated and the shape of the package can be maintained, and the package is placed in the disposal space in a state of being securely packed. be able to. As a result, the limited waste final disposal space can be effectively used.
[0038]
A closed space 10 surrounded by a concrete shielding wall is used as a disposal space. Such an enclosed space is initially constructed as a pool-like (concave) facility with an open top at a location with appropriate location conditions. After the packaging waste cue sections 9 are arranged and stacked in the pool, the upper opening is closed with a concrete panel, and sealed by, for example, mortar treatment or concrete pouring work.
[0039]
Next, in FIG. 1 (f), a plurality of packing waste cubes 9 are stored in a closed state in a closed space 10 surrounded by a concrete shielding wall. Here, as shown in FIG. 1 (f), one end of an air exhaust pipe 11 a is piped through a concrete shielding wall at the bottom of the closed space 10, and an open / close valve 12 a is provided at an outer end of the pipe. The vacuum compressor 13 and the nitrogen concentration detecting device 14 are connected via the unit.
[0040]
In addition, a nitrogen gas introduction pipe 11b is piped through the concrete shielding wall at the upper part of the closed space 10, and a regulator outlet of the liquefied nitrogen cylinder 15 can be connected to an outer end of the pipe 11b through an opening / closing valve 12b. It has become.
[0041]
In FIG. 1F, while the air in the closed space is sucked and exhausted by the vacuum compressor 13 through the pipe 11a, the vaporized nitrogen gas is introduced from the cylinder 15 into the closed space through the pipe 11b.
[0042]
In this manner, nitrogen gas is introduced from the pipe 11b while the air in the sealed space 10 is sucked and exhausted from the pipe 11a, and the air in the sealed space is replaced with nitrogen gas. As a result, it becomes impossible for insects and small animals to inhabit, and even if the waterproof sheet 6 for sealing and packaging the waste is damaged or broken, microorganisms can propagate, and the waste is oxidized and corroded to generate gas. Things can be avoided.
[0043]
It should be noted that whether or not the air inside the enclosed space 10 has been sufficiently replaced with nitrogen gas is monitored by the nitrogen concentration detector 14 connected to the vacuum compressor 13 for monitoring the nitrogen concentration of the air discharged from the vacuum compressor 13. Can be determined. That is, when the nitrogen concentration in the discharged air becomes almost 100%, it can be determined that the replacement is completed.
[0044]
In this embodiment, the inert gas introduced into the closed space 10 is nitrogen gas immediately after vaporization from liquefied nitrogen. Therefore, the nitrogen gas introduced into the closed space 10 from the pipe 11 is very low. It is low temperature. The concrete shielding wall has a high heat insulating property, and therefore, the cooling effect by the nitrogen gas can cool the waste for a long period of time, and can prevent an increase in the internal temperature even if heat is generated by, for example, fermentation. In addition, since the inside of the closed space 10 is kept cool, there is no propagation of microorganisms and no oxidization and corrosion of the waste. Therefore, generation of gas from the waste is also prevented, and the internal pressure of the closed space 10 rises. Can be prevented for a long time, and no cracks or the like occur on the concrete shielding wall.
[0045]
Furthermore, since the nitrogen gas introduced into the closed space 10 does not deteriorate for about 50 to 100 years, it prevents fermentation of waste, propagation of insects / small animals, microorganisms, etc., and oxidation / corrosion of waste over a long period of time. be able to.
[0046]
In the above description, the case where the air inside the closed space 10 is replaced with nitrogen gas has been described, but the same effect can be obtained even if the air inside the closed space 10 is replaced with carbon dioxide gas. . However, in this case, a pipe 11a for sucking / exhausting air from the closed space 10 is provided at an upper portion in the closed space 10, and a pipe 11b for introducing carbon dioxide gas is provided at a bottom portion in the closed space 10. The provision is as described above.
[0047]
After replacing the inside of the closed space 10 with the inert gas as described above, the open / close valves 12a and 12b and the exposed piping are filled with concrete outside the concrete shielding wall. FIG. 1 (g) shows a state in which the open / close valves 12a and 12b and the exposed portion of the pipe below the open / close valves 12a and 12b are buried in the concrete block 16.
[0048]
Then, the soil covering 17 is put on the concrete block 16 and the upper concrete shielding wall, and the waste treatment facility is buried in the soil.
[0049]
Note that it is preferable to sample the gas inside the closed space 10 at intervals of about once every 5 to 10 years. In this case, the concrete block 16 is crushed with a hammer or the like by digging an embankment, and the nitrogen concentration of the gas in the upper part of the enclosed space is detected by the nitrogen concentration detector 14 in the manner shown in FIG. If it has fallen from%, the nitrogen gas may be charged again. Of course, when carbon dioxide gas is used as the inert gas, sampling of the internal gas is performed from the bottom of the closed space 10.
[0050]
【The invention's effect】
INDUSTRIAL APPLICABILITY As described above, the present invention effectively utilizes a limited waste disposal space in order to store individually compression molded and hermetically sealed waste in an enclosed space formed by a concrete shielding wall. In addition, the air inside the enclosed space containing the waste is replaced with inert gas, making it impossible for insects and small animals to inhabit. Oxidation can be prevented, and diffusion and leakage of harmful substances contained in waste can be stably prevented over a long period of time.
[0051]
In addition, since the inert gas does not deteriorate for a long period of time, the diffusion of contamination by harmful substances from the waste can be prevented for a long time. An increase in internal pressure can also be prevented.
[0052]
Further, in the present invention, since the concrete shielding wall forming the closed space is covered with the embankment, the concrete shielding wall is shielded from solar radiation and the outside air and kept in a moist state, and therefore, it is possible to prevent deterioration of the concrete and occurrence of cracks. You can also.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing steps of a waste disposal method according to one embodiment of the present invention.
[Explanation of symbols]
2 belt conveyor 3 waste 4 pressing device 5 waste cube 6 waterproof sheet 7 heat welding device 8 vacuum compressor 9 packing waste cube 10 closed space 11a, 11b piping 12a, 12b opening and closing Valve 13 Vacuum compressor 14 Nitrogen concentration detecting device 15 Liquefied nitrogen cylinder 16a, 16b Concrete block 17 Covering soil

Claims (5)

Individually sealed waste compacts are stored inside the enclosed space surrounded by concrete shielding walls, and the air inside the enclosed space is replaced with an inert gas. A waste disposal method comprising sealing a pipe outside a concrete shielding wall and embankment on the concrete shielding wall above the enclosed space. The waste disposal method according to claim 1, wherein nitrogen gas is used as the inert gas. The waste disposal method according to claim 1, wherein a low-temperature gas is used as the inert gas. When replacing the air inside the enclosed space with an inert gas, the air is sucked and exhausted from the bottom of the enclosed space, and nitrogen gas is introduced as an inert gas from the top of the enclosed space to increase the nitrogen concentration of the exhausted air. The waste disposal method according to claim 1, wherein the replacement operation is terminated based on the information. After each piping for air suction evacuation and inert gas introduction after the replacement work sealed outside the concrete shielding wall, waste disposal according to claim 1, characterized in that to the sealing portion further concrete filling Method.

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