JP4436953B2 - Waste disposal method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a waste treatment method using molten slag as a treated soil material.
[0002]
[Prior art]
In the managed waste final disposal site, earth and sand such as residual soil or nonwoven fabric is generally used as a material in direct contact with waste, and in particular, residual soil is often used as intermediate covering soil. These materials are used as a breathable material, and have a function of activating aerobic bacteria in the soil and promoting the decomposition of organic components by promoting aeration with respect to organic components in the waste.
[0003]
However, earth and sand and non-woven fabrics are clogged early due to fine particles and microorganisms in the waste, and their functions of water permeability and air permeability are likely to deteriorate, decomposition is significantly delayed, and use as a disposal site is terminated. After the closure, the curing period until normal land use was possible was as long as 25 to 30 years, and there was a problem in terms of effective use.
[0004]
[Problems to be solved by the invention]
By the way, the present inventors paid attention to molten slag as a material excellent in air permeability. This molten slag is a glassy or crystalline particulate material with an average particle size of about 1 to 18 mm obtained by cooling waste after melting it at a high temperature of 1200 ° C or higher. In addition to being attracting attention as a substance, additive material for paving materials, building materials, etc., it has been found that the properties of molten slag itself are superior to earth and sand as soil materials for waste treatment in the following points.
[0005]
(1) Since it is glassy, the particle surface is smooth and fine particles are difficult to adhere.
(2) Treated with high heat and sterilized, and it is difficult for microorganisms to inhabit because nutrients do not adhere easily.
(3) Since the surface is smooth, the water permeability is good and the flow velocity is large, so that the deposits are washed out and easily flow out to the lower layer.
(4) Uniformity in terms of water permeability coefficient and air permeability, uniform water replenishment is possible, and aerobic conditions are uniform, and waste is rendered harmless early and uniformly.
(5) Since water permeability and air permeability are good, it can be constructed thinner than the soil thickness and the landfill efficiency in the disposal site is good.
(6) Since the molten slag itself is produced by processing waste, the material is cheaper than sand and can be obtained regularly.
[0006]
The present invention has been made on the basis of the above points, and its purpose is that waste can be processed at low cost by effective use of molten slag, and early detoxification after the end of the function as a treatment plant. The present invention provides a waste disposal method that can be achieved.
[0007]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention melts waste or incinerated ash as protective soil provided on the bottom and slope of a water shielding sheet laid on the bottom and slope of a new waste disposal site. Further, the molten slag obtained by cooling is laminated, and at that time, the melted slag packed in a bag is laminated on the slope portion, and the molten slag is laminated as an intermediate covering every time a certain amount of waste is deposited. It is characterized by doing. In addition, the present invention provides a protective soil to be provided on the bottom and the entire slope of the water shielding sheet laid on the bottom and slope of a new waste disposal site, and is obtained by melting and cooling the waste or incinerated ash. The molten slag is laminated, and the molten slag is laminated as an intermediate cover every time a certain amount of waste is deposited. Therefore, in the method of the present invention, it is possible to perform processing that takes advantage of the characteristics of the molten slag described above.
[0008]
As used herein, molten slag refers to waste such as municipal waste, general waste, industrial waste (waste plastics, etc.), or sludge (sewage sludge, straw sludge, food processing sludge, etc.) Molten slag produced by melting at a high temperature of 1200 ° C or higher in a chemical melting furnace or the like, or incinerated ash, for example, fly ash or incinerated ash generated by incineration of the waste is further heated to a high temperature of 1200 ° C or higher. It refers to the molten slag produced by melting at, and there are the following methods for cooling it.
[0009]
(1) Granulated slag: A glassy slag produced by directly injecting molten slag into water and quenching and solidifying it. The particle size is relatively fine.
(2) Air-cooled slag: Glassy slag produced by allowing molten slag to stand in the air and naturally cool and solidify. The particle size is relatively coarse.
(3) Slow cooling slag: Crystallized slag produced by controlling the cooling temperature of molten slag to allow sufficient cooling time to promote crystallization.
In the present invention, the molten slag obtained by the above water granulation, air cooling, and slow cooling is used alone or by mixing these slags.
[0011]
Further, the present invention relates to water permeability by molten slag obtained by melting waste or incinerated ash in a column or wall extending vertically in the waste stored in an existing waste disposal site and further cooling. And a layer having air permeability is formed. According to the present invention, even in an existing facility, it is possible to perform processing that makes use of the characteristics of molten slag from the middle.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment in which the present invention is applied to a new waste disposal site. In the figure, the waste disposal site 1 excavates the ground E such as a mountainous area almost along the topography, and shapes the surface flat or artificially converts the flat ground E into a substantially inverted trapezoidal shape. It was obtained by excavation.
[0013]
As construction work after excavation, first, excavating the bottom, piping the underground culvert 2 for groundwater collection and drainage, and then laying a groundwater collection and drainage protection mat 3 made of non-woven fabric or the like along the recess, Prevent penetration of the groundwater inside. Next, for example, the double water-impervious sheet 4 is laid along the recess, and the periphery is fixed to the ground surface part GL to shield the inside and outside of the disposal site.
[0014]
Next, the perforated tube 5 is piped at the bottom. The downstream side of the perforated pipe 5 is connected to a wastewater treatment facility 6 outside the treatment plant 1, and the water detoxified here is discharged into a river or the like.
[0015]
The waste water treatment facility 6 includes a raw water tank 31, a calcium removal treatment device 32, a biological treatment device 33, a coagulation sedimentation device 34, a sand filtration adsorption device 35, and a desalination treatment device 36.
[0016]
The waste water supplied from the perforated pipe 5 is stored in the raw water tank 31 and then supplied to the calcium removal processing device 32. The calcium removal processing device 32 removes calcium contained in the waste water. After adding and stirring caustic soda, sulfuric acid, sodium carbonate, etc., the flocculant, caustic soda and, if necessary, the polymer are added and stirred, and the precipitation tank To remove the calcium scale by coagulation precipitation.
[0017]
The biological treatment device 33 decomposes BOD, ammonia nitrogen, and the like contained in the wastewater by the biochemical reaction of the microorganism and reduces it to nitrogen gas, and aeration-treats the wastewater charged with the microorganism.
[0018]
The coagulating sedimentation device 34 removes COD, SS, heavy metals and the like contained in the waste water. The coagulating agent, heavy metal fixing agent and the like are added and stirred, and then coagulated and precipitated.
[0019]
The sand filtration adsorption treatment device 35 removes COD, SS, dioxins and the like contained in the waste water, and consists of a sand filtration device and an activated carbon adsorption tower. After removing SS etc. with the sand filtration device, the activated carbon adsorption tower Dioxins are removed by adsorption.
[0020]
The desalting apparatus 36 concentrates and separates chlorine ions from waste water by electrodialysis.
[0021]
In the above configuration, waste water such as leachate discharged from the perforated pipe 5 is discharged into the raw water tank 31, the calcium removal processing device 32, the biological treatment device 33, the coagulating sedimentation device 34, and the sand filtration adsorption device 35. Since it is guided to the desalination treatment device 36 in order and harmful to the environment, calcium scale, BOD, COD, ammoniacal nitrogen, SS, hydrogen chloride, heavy metals, dioxins, etc. are removed and discharged into rivers, etc. There is no risk of polluting the environment.
[0022]
The components of the wastewater treatment facility 6 are leachable wastewater due to the type of waste to be landfilled (waste 11), for example, garbage, fly ash or incineration ash generated by incineration of waste, or incombustibles. Needless to say, it is not limited to the present embodiment, and may be selectively used as appropriate.
[0023]
In addition, the waste water treatment facility 6 is installed on the ground surface GL in addition to the waste disposal site 1 or installed in the ground E for the purpose of effective use of land, restrictions on installation area, etc. The installation location is appropriately selected depending on the design and specifications.
[0024]
Next, the perforated pipe 5 is connected to a state in which a gas vent pipe 7 made of a perforated pipe is started up. A ventilation fan 8 is connected to the upper part of the degassing pipe 7, and air is circulated from the perforated pipe 5 and the surrounding parts by rotation of the ventilation fan 8 at all times.
[0025]
After completion of the above construction, the molten slag 9 is sprinkled as a leaching / collecting drainage protective soil at the bottom, and spread to a certain thickness. In addition, by arranging the sandbag 10 packed with molten slag on the peripheral inclined surface, a preparation system for receiving waste is prepared, and the waste 11 can be dumped from this stage. The gas vent pipe 7 is surrounded by a clogging prevention material 12 made of molten slag and nonwoven fabric to ensure air circulation.
[0026]
As the work during the dumping of the waste, the work of laminating the molten slag 9 as covering soil is repeated every time the waste 11 is accumulated to some extent. Currently, approximately 50 cm of soil is covered every approximately 3 m of waste. However, when molten slag 9 is used, the thickness is less than this, and as a result, compared to a disposal site of the same volume, waste 11 can be increased.
[0027]
In addition, the sandbag 10 is sequentially piled up every time the waste 11 is deposited. Similarly, the degassing pipe 7 is sequentially extended in accordance with the deposition height.
[0028]
If the disposal site 1 becomes full by repeating the above operations, by laminating molten slag 9 as the final covering soil and making it roughly flush with the ground surface part GL, finally filling the normal soil 14 for vegetation, As shown in the drawing, the role as the waste disposal site 1 is terminated, and thereafter, a curing period is required until it is rendered harmless. In this case, the molten slag 9 or the sandbag 10 in which the molten slag 9 is packed is rich in water permeability and air permeability, and has surface lubricity, so that the organic content in the waste 11 is decomposed without causing clogging. The activity of the aerobic bacteria is retained, and the organic matter is decomposed at an early stage.
[0029]
The harmful ions contained in the waste are continuously dissolved in the water penetrating into the interior by rain water, etc., discharged through the perforated pipe 5 to the outside of the treatment plant, and processed through the waste water treatment facility 6. In some cases, the closure period will be shorter than the conventional curing period.
[0030]
In addition, in the state of detoxifying the interior after the above curing period, useful materials such as rare metals are also included. Therefore, it is possible to excavate them later and take out only useful materials. In this case, since the molten slag 9 has a particle size as compared with the conventional earth and sand, the molten slag 9 can be easily classified, and separation work in recycling useful materials is also simplified.
[0031]
Next, FIG. 2 shows 2nd embodiment at the time of applying this invention to renovation of an existing waste disposal site. In addition, this waste disposal site assumes a state in which ventilation is not sufficient and organic components are not sufficiently decomposed even after a long time.
[0032]
As shown in the figure, the existing waste disposal site 20 is refurbished by constructing a plurality of columns of drains 21 made of molten slag through the wastes 22 by a sand drain method, and thereby, in the disposal site 20. In addition to improving the aerobic condition, in the surface portion, after the perforated tube 23 was piped, a sand mat layer 24 made of molten slag was formed, and this upper surface was covered with a water shielding sheet 25 to shield the inside, Fill the normal soil 26 for vegetation.
[0033]
And the edge part of the perforated pipe | tube 23 is pulled out outside, and the circulation of the air inside and outside the disposal site 20 is accelerated | stimulated through the drain 21 and the perforated pipe | tube 23 by providing the ventilation fan 27 in this part, and aerobic conditions are Will improve.
[0034]
Next, as a third embodiment, a form in which leachate is purified and reused in a wastewater treatment facility in a new waste disposal site according to the present invention will be described. FIG. 3 shows a third embodiment, and the same apparatus as that in FIG. 1 is denoted by the same reference numerals as in FIG.
[0035]
The third embodiment is a closed system in which wastewater discharged from the perforated pipe 5 is detoxified by removing harmful substances with the wastewater treatment device 6 and then recycled to the waste disposal site 1 to purify waste. Thereby, waste can be purified without discharging waste water into a river or the like.
[0036]
In the present embodiment, the entire surface of the molten slag 9 that is the cover soil is covered with a roof-like cover 41 such as a roof made of steel, plastic resin, ceramics, etc., and protected from rain. Then, the purified water supply pipe 43 is fixed to the roof-like cover 41 by the support tool 42 on the inner surface of the lower part of the roof-like cover 41. A plurality of watering devices 44 are attached to the purified water supply pipe 43 at predetermined intervals. In addition, the ventilation fan 8 is protruded from the roof-like cover 41 so that air can circulate.
[0037]
In such a configuration, at the time of start-up, water such as tap water or well water from the outside is supplied with purified water supply pipe at the top of the roof-like cover 41 by opening the valve 50 and using the pump 51 via the line L3. The purified water is supplied to the purified water supply pipe 43 through the opening 46 and sprinkled by the watering device 44. The sprinkled purified water penetrates into the waste 11 and the molten slag 9 and is collected in the perforated pipe 5 as leached collection wastewater and purified by the wastewater treatment device 6. Then, the water is again introduced into the purified water supply pipe 43 through the lines L1 and L2 by the pump 45 and sprinkled by the watering device 44.
[0038]
When it is rendered harmless by repeated circulation through wastewater purification, the roof covering 41, the purified water supply pipe 43, the ventilation fan 8, etc. are removed, and normal soil is filled in the surface of the molten slag 9 as necessary. It can be used as normal land.
[0039]
As described above, in this embodiment, the waste water is circulated and used to purify the waste. Therefore, the waste can be cured stably and systematically without being affected by external rainfall. In addition, since wastewater is not discharged outside the system, there is no risk of environmental pollution due to leachate and drainage.
[0040]
Next, as a fourth embodiment, another embodiment in which leachate is purified and reused in a wastewater treatment facility in a new waste disposal site according to the present invention will be described. FIG. 4 shows a fourth embodiment, and the same apparatus as that of FIG. 3 is denoted by the same reference numerals as those of FIG.
[0041]
In the fourth embodiment, a purified water supply pipe 61 provided with water passage holes 62 at appropriate intervals is disposed on the surface of the molten slag 9 that is the cover soil, and a water shielding sheet made of resin or steel. It protects from rain etc. by laying the water shielding material 64 such as.
[0042]
The purified water supply pipe 61 is sealed at one end and connected to the line L2 at the other end 63 so that purified water from the waste water treatment facility 6 is supplied.
[0043]
Then, as in the third embodiment, at the time of start-up, water such as tap water or well water from the outside is supplied to the purified water supply pipe 61 via the line L3 by opening the valve 50 and opening the valve 50. Water is sprayed from the water passage hole 62. The sprinkled purified water penetrates into the waste 11 and the molten slag 9 and is collected in the perforated pipe 5 as leached collection wastewater and purified by the wastewater treatment device 6. Then, the water is again introduced into the purified water supply pipe 61 through the lines L1 and L2 by the pump 45 and sprayed through the water passage hole 62.
[0044]
When it is rendered harmless by repeated use of wastewater for purification, the purified water supply pipe 61, the water shielding material 64, the ventilation fan 8, etc. are removed, and if necessary, ordinary soil is embanked on the molten slag 9 Can be used as normal land. In addition, land use can also be accelerated | stimulated by embedding a curing soil on the upper part of the water-impervious material 64 from the initial stage of waste purification.
[0045]
Moreover, while connecting the edge part of the purified water supply pipe 61 with the branch pipe (not shown) of the purified water from L2, it is a grid | lattice form and a circumferential form over the ground surface whole surface of the molten slag 9 which is covering soil. In this case, uniform purified water can be sprinkled.
[0046]
Instead of the water shielding material 64, a cover such as a roof may be used.
[0047]
Moreover, you may make it supply purified water from the both ends of the purified water supply pipe 61 via the line L2.
[0048]
【The invention's effect】
As is clear from the above explanation, according to the waste treatment method of the present invention, waste can be treated at low cost by the effective use of molten slag, and early detoxification should be achieved after the end of the function as a treatment plant. Can do. Therefore, the molten slag to which the present invention is applied is suitable not only as a treatment soil when a disposal site is newly established, but also as a treatment soil for repairing an existing disposal site.
[Brief description of the drawings]
FIG. 1 is a cross-sectional explanatory view showing a first embodiment when the present invention is applied to a new waste disposal site.
FIG. 2 is a cross-sectional explanatory view showing a second embodiment when the present invention is applied to refurbishment of an existing waste disposal site.
FIG. 3 is a cross-sectional explanatory view showing a third embodiment of the present invention.
FIG. 4 is a cross-sectional explanatory view showing a fourth embodiment of the present invention.
[Explanation of symbols]
1,20 Waste disposal site 9 Molten slag 10 Sandbag 11 and 22 filled with molten slag Waste 21 Drain made of molten slag 24 Sandmat layer made of molten slag

Claims (3)

Laminated waste slag obtained by melting waste or incinerated ash and cooling is used as protective soil to be provided on the bottom and slope of the water shielding sheet laid on the bottom and slope of a new waste disposal site. In this case, a waste disposal method characterized in that the sloped portion is laminated with a bag of the molten slag, and the molten slag is laminated as an intermediate covering every time the waste is deposited to some extent . As a protective earth provided on the bottom and law face the entire surface of the water shield sheet laid on the bottom and slope of the landfill site of new, laminated molten slag obtained by melting and further cooled waste or incinerated ash Then, each time the waste is deposited to some extent, the molten slag is laminated as an intermediate covering soil . A layer that has water permeability and breathability with molten slag obtained by melting waste or incinerated ash in a column or wall extending vertically in the waste stored in an existing waste disposal site and cooling it. A waste treatment method characterized by comprising:

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