JPS6016528B2 - Waste landfill method - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a waste landfill construction method, and in particular covers the upper part of a landfill site to prevent rainwater from penetrating, and at the same time blows air into the landfill site to dispose of the landfill site. The air is passed through the material layer from above to below to promote aerobic decomposition of the organic matter in the waste, and the leachate produced by this decomposition is circulated by watering to the landfill site to disintegrate the waste layer. This relates to a method of landfilling waste that is purified as furnace material.

The methods of processing and disposing of municipal waste can be roughly divided into three methods: composting for reuse or resource recovery, methods that perform intermediate treatment such as incineration, crushing, and compression, and then dispose of it in a landfill, and methods that dispose of it in a landfill without treatment. It is divided into different methods.

Of this amount, the amount that is disposed of in landfills without treatment is estimated to be about 40-50% of the amount of waste generated. Conventionally, one of the following methods has been adopted to dispose of waste in a landfill without treatment. In other words, there are so-called anaerobic landfills in which waste is simply dumped in a concavely formed landfill site, and so-called anaerobic landfills in which waste, covered soil, waste, and covered soil are repeatedly formed in a concavely formed landfill site. Anaerobic sanitary landfill, in which an impermeable layer is formed at the bottom of the concave landfill site and a drainage pipe is provided, and layers of waste and covering soil are alternately formed on this, similar to the anaerobic sanitary landfill. These include so-called improved sanitary landfills, semi-aerobic landfills, and the most effective aerobic landfills. However, according to these methods, the amount of liquid leached from the landfill site increases due to the influence of rainwater that permeates into the landfill site, and the quality of the water is contaminated by leachate etc. from the organic matter contained in the waste. As a result, it has become a source of secondary pollution around the landfill site.

Currently, in order to treat such leachate, an excessively large treatment facility is required at the landfill site. Furthermore, the decomposition of waste is easily affected by changes in temperature and may not be sufficient in some cases. The inventors are currently researching the prevention of secondary pollution to the environment due to leachate from waste landfill sites.
He completed an invention to eliminate the drawbacks of the conventional waste landfill method, and filed a patent application for the invention (Tokukoshi Sho 52-70225).

The feature of this invention is that the upper part of the landfill site is covered to prevent rainwater from seeping in, and at the same time, air is introduced into the landfill site to promote aerobic decomposition of organic matter in the waste. Ta. This invention is the invention related to the above patent application (Samuraikoshi Sho 5
2-70225).

That is, in the embodiment of the above invention, in addition to a water collection pipe that collects the leachate and discharges it to the outside, an air inlet pipe that supplies air to the landfill site is disposed below the landfill site. A blower connected to the air supply pipe is used to forcefully send air, passing the air from below to above the landfill site in order to aerobically decompose the organic matter contained in the waste. There is. Therefore, in that embodiment, a blower with a certain amount of output was required to introduce air. Furthermore, because the flow of leachate generated by the decomposition of organic matter and the flow of air oppose each other, a short-circuit flow of air occurs within the waste layer, which acts as resistance and slows down the drainage of leachate, and also reduces the air flow. Therefore, a more powerful blower was required. This invention solves these problems and also
This has been improved so that the air that has passed through the waste layer can be easily treated if necessary.

That is, the present invention allows air necessary for aerobic decomposition of organic matter contained in waste to pass from above to below the landfill site, thereby separating the flow of the leachate and the flow of air. By matching, the leachate can be drained more smoothly, the waste layer can always be kept in a state suitable for aerobic decomposition, and if necessary, the air that has passed through the waste layer can be easily treated. Can be done.

Furthermore, by installing ventilation standpipes in appropriate locations, this waste landfill construction method allows for even smoother circulation of air within the waste layer. Therefore, the purpose of this invention is to prevent wastewater from flowing out from a landfill site to the surrounding area, and the purpose of this invention is to promote aerobic decomposition of organic matter contained in waste. A further object of the present invention is to purify undecomposed sewage contained in waste, and a further object of the invention is to prevent the scattering of malodorous components and the scattering and leakage of waste. In particular, a further object of the present invention is to drain the leachate even more smoothly and to maintain the waste layer in a state suitable for aerobic decomposition of organic matter. Another object of the present invention is to facilitate the treatment of air that has passed through the layer when it is necessary. The purpose of this facility is to prevent sewage and odor pollution at landfill sites.

That is, in the present invention, as in the illustrated embodiment, the upper part of a landfill site 2 whose side and bottom parts are formed with an impermeable layer 1 is covered with a covering material 3 made of an impermeable material. In addition to preventing rainwater from penetrating into the waste material, air is introduced into the inside of the covering material 3, and the air is passed through the waste layer 4 of the landfill site 2 from above to below, thereby reducing the amount of water contained in the waste. The organic matter is decomposed aerobically, the leachate produced by this decomposition is collected, and it is transferred to the landfill site 2.
Identified a waste landfill method characterized by circulating water from the top surface and purifying it using a watering hearth method using the waste layer 4 as the furnace material, thereby performing aerobic decomposition of waste and wastewater treatment at the same time. According to the present invention, the upper part of a landfill site 2 whose side and bottom parts are formed with an impermeable layer 1 is covered with a coating 3 made of an impermeable material.
' to prevent rainwater from penetrating into the landfill site 2, and to provide ventilation standpipes in the waste layer 4 of the landfill site 2 with a large number of holes on the outer periphery and a gateway at the top. 15 is installed, air is introduced into the inside of the coating 3' to expand the coating 3' upward, and the air is passed directly from above to below through the ventilation standpipe 15. , the organic matter contained in the waste is aerobically decomposed, the leachate produced by this decomposition is collected, and this is circulated in the landfill site 2 by water spraying from the top of the landfill site 2 to form a waste layer. A waste landfill construction method is provided as a combined invention, which is characterized in that waste is purified by a watering hearth method using No. 4 as a stagnation material, and aerobic decomposition of waste and wastewater treatment are performed simultaneously.

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

An impermeable layer 1 is formed on the sides and bottom of the landfill site 2.

The impermeable layer 1 is made of rubber, synthetic resin, asphalt, concrete, etc., which is impermeable to water, has corrosion resistance, and has sufficient strength. Thereby, the landfill site 2 and the outside of the impermeable layer 1 are cut off. The upper part of the landfill site 2 is covered with a covering material 3 made of a water-impermeable material.

Although it is sufficient for the coating material 3 to have a structure that prevents rainwater from entering the landfill site 2, a coating material 3' is used in this embodiment. Although the coating 3' is not particularly shown, it may be formed by joining together a large number of unit membranes each having a relatively small area, or it may be formed by a single coating 3'. When forming a single film 3', there is no need to join many pieces together, so extra work such as joining work becomes unnecessary, but the shape and size are naturally limited. On the other hand, when forming a large number of unit films by joining them together, a joining operation is required, but it is possible to form a film 3' that matches the area and shape of the landfill site 2. A reinforcing rope is sewn into the periphery of this unit membrane, and the reinforcing rope has metal fittings for connection.
The membrane 3' is assembled by overlapping the circumferences of each unit membrane and tightening the metal fittings with bolts. Although the unit membranes are connected by bolts, the peripheral parts of the unit membranes overlap, so that when the membrane 3' is tensioned by air pressure as described later, the shielding performance between the inside and outside is improved. Landfill site 2 is waste layer 4
and a covering layer 9 are alternately laminated.

A water collection pipe 5 is arranged along the bottom of this landfill site 2. The water collection pipe 5 is connected to an external water collection bit 7 and is provided with a pressure regulating valve 16 at the entrance portion facing the water collection bit 7. The pressure regulating valve 16 adjusts the degree of opening and closing of the opening section of the water collection pipe 5 to adjust the air pressure within the coating 3' and within the landfill site 2. Further, the tip of the air inlet pipe 6 connected to the blower 8 is exposed inside the coating 3' covering the upper surface of the landfill site 2. The coating 3' is supplied from the blower 8 through the air supply pipe 6.
Air is introduced into the membrane 3' and fills the membrane 3', causing it to expand upwardly. This air pressure is 30~
By maintaining Ag on the 50 side, the expanded state of the coating 3' can be maintained, and air can pass from the top surface of the landfill site 2 to the bottom. The air passes through the laminated soil cover layer 9 and waste layer 4 to the water collection pipe 5 at the bottom.
and is discharged to the external collecting bit 7 via the pressure regulating valve 16. In this case, air comes into contact with the waste and the organic matter contained in the waste is decomposed under aerobic conditions.
This decomposition is mainly thought to occur in two ways: by aerobic bacteria and by oxidation. The leachate produced by the decomposition of organic matter has a higher biochemical oxygen demand (BOD) than the leachate produced from anaerobic landfills such as the conventional example.
Water quality evaluation indicators such as , chemical oxygen demand (COD), and ammonia nitrogen (41 N/day) are improved. A leachate water sprinkler 10 is provided between the upper surface of the landfill site 2 and the coating 3', and is connected to a submersible pump 11 in the water collection bit 7 via a water pipe 12.

13 is a dam, and behind the water collection bit 7 in FIG. 1 is a rainwater storage tank (not shown).

Thus, the coating 3' and the impermeable layer 1 prevent rainwater from penetrating into the landfill site 2, and at the same time, air is introduced from the air inlet pipe 6 by the blower 8.

Air is introduced downward from the top of the landfill site 2.
This is achieved by maintaining the inside of the coating 3' at an appropriate air pressure, but by using the ventilation standpipe 15 as shown in the figure, a sufficient amount can be supplied evenly and more efficiently. The ventilation standpipe 15 has a large number of holes around it, and the air introduced from the upper part of the ventilation standpipe 15 installed in the landfill site 2 flows into the landfill site 2 through the holes. sent. Of course, in this case as well, the air flows through the ventilation standpipe 15.
The waste is also directly delivered to the landfill site 2 from other sources. Further, as described above, the leachate produced by the decomposition of organic matter under aerobic conditions contains a sap of decomposition that is mainly composed of water.

This is introduced from the bottom of the landfill site 2 through a water collection pipe 5 to a water collection bit 7. The leachate collected in the bit 7 is recirculated from the leachate sprinkler 10 to the landfill site 2 via the connecting pipe 12 by the submersible pump 11. Here, the leachate is oxidized and purified by a forced watering hearth method using the waste layer 4 and the soil cover layer 9 as furnaces, and is introduced from the bottom through the water collection pipe 5 into the water collection bit 7 in the same manner as described above. The leachate is recycled from the water sprinkler 10 to the landfill site 2 and purified by repeated recycling. This forced watering hearth system reduces the biochemical oxygen demand (OD), chemical oxygen demand (COD), and ammonia nitrogen (N ratio 11N) of the leachate.
), etc., satisfy the standard values stipulated by law, the leachate is purified and can be discharged. Therefore, there is no need to separately provide a treatment facility for the leachate, but even if it is necessary, the treatment facility can be small because the purification rate is high. This purification is achieved by forming a furnace membrane of aerobic microorganisms on the surface of the furnace when the leachate passes through the landfill site 2, and by contacting this with the leachate, colloidal substances and dissolved substances in the leachate are removed. be purified.

In order to maintain this furnace material in an aerobic state, it is necessary to provide a sufficient supply of oxygen, but this can be done simply by keeping the air pressure within the coating 3' at an appropriate level. It can be made more effective by installing That is, when the ventilation standpipe 15 is not used, fresh air containing a large amount of oxygen is always supplied to the upper part of the landfill site 2.
Oxygen in the air is sequentially consumed as it decomposes organic matter as it progresses to the bottom, and as it progresses to the bottom, the amount of oxygen that can be donated to the decomposition decreases significantly. The decomposition rate is different. However, if this ventilation standpipe 15 is used, fresh air containing a large amount of oxygen can be directly supplied to each deep and shallow waste layer 4 of the landfill site 2 through the ventilation standpipe 15 and through its numerous holes. Therefore, aerobic decomposition of organic matter can be further promoted. In addition, since the flow of air and the flow of leachate match, no short-circuit flow of air occurs within the waste layer 4, allowing smoother air circulation and increasing the drainage speed of the leachate. The waste layer 4 can always be maintained in a state suitable for aerobic decomposition of organic matter, promoting the decomposition of organic matter in the waste, promoting purification of leachate, and improving the structure of the coating material 3 by expanding the coating 3'. Contribute to simplification. When the coating 3' is formed as a single piece with no gaps, it is necessary to provide a means for automatically adjusting the internal air pressure to prevent the coating 3' from bursting due to excessive air pressure.

In addition, when multiple unit membranes are spliced together, if tension occurs in the membrane 3', the overlapping parts of the unit membranes, which are the constituent materials, will be bonded together by the pressure of the internal air, so the shielding properties inside and outside the membrane 3' will be reduced. Becomes good. However, if the coating 3' seals the upper part of the landfill site 2, the internal air pressure will become excessive and the air supply from the air supply pipe 6 will stop, or the coating 3' will rupture. ' is provided with a gap to allow air leakage and prevent rainwater from entering.
In the case of this embodiment coating 3', air leaks from the overlapping portions of the unit membranes that constitute each unit membrane. If an amount of air corresponding to this amount of leakage is sent from the air supply pipe 6, air will be supplied into the landfill site 2 while maintaining a constant pressure inside the coating 3', thereby achieving aerobic conditions. , the expansion of the coating 3' is ensured. The inflated state can be maintained if the pressure difference between the inside and outside of the coating 3' is approximately 10 to 3 Aq. The coating 3' can also have a double structure to prevent the temperature of the landfill site 2 from decreasing in winter. This is to prevent a decrease in the decomposition rate of organic matter due to a drop in temperature. Also, the coating material 3 has a coating 3'
It is also possible to use a fixed, semi-cylindrical roof or other type without using a roof. In that case, it is of course unnecessary to maintain the shape of the sheathing material 3 using the air pressure introduced, but it is also possible to use a structure that prevents rainwater from entering and allows the air that is introduced to leak appropriately. A means for maintaining the pressure within the coating 3' at an appropriate level of 30 to 50 Aq is required. The landfill site 2 is surrounded by a coating 3' and other covering materials 3 and an impermeable layer 1, and there is no permeation of water from the outside. If the water required to maintain the decomposition of the leachate in an optimal state cannot be supplied, rainwater is sent from a rainwater storage tank (not shown) to the leachate sprinkler 10 via a submersible pump (not shown). Suitable moisture can be obtained by sprinkling water onto the landfill site from the water sprinkling device 10.

When the aerobic decomposition of the organic matter is completed, there will be no leaching of liquid from the waste or generation of bad odors, so the covering material 3 will be removed and the landfill site 2 will be used for multiple purposes as a landfill. can be provided.

In addition, when the coating 3' is used as described above for the coating material 3, it is sufficient to attach the coating 3' around the landfill site 2, making it easy to install and remove, and Easy to store. Furthermore, in the case of the coating 3' which is made by piecing together a plurality of unit membranes, maintenance and storage are easy because the membrane surface can be partially replaced, repaired, or relocated in case of damage or aging. As is clear from the above, according to the present invention, since the sides, bottom and upper part of the landfill site 2 are surrounded by impermeable materials, there is no possibility that leachate will overflow and leak into the surrounding area. This method does not cause contamination of lakes and marshes, and prevents the scattering and outflow of waste and bad odors. In addition, leachate can be drained more smoothly, and the waste layer 4 is always suitable for aerobic decomposition of organic matter. By maintaining this condition, the decomposition of organic matter contained in the waste can be further promoted, and furthermore, the leachate generated from the waste can be purified simply by circulating it.

Therefore, there is a significant effect that waste treatment can be made extremely effective in a short period of time without causing environmental pollution. Furthermore, if the air that has passed through the waste layer needs to be treated, it can be easily disposed of, and there is no need to install an air supply pipe at the bottom of the landfill site. can prevent sewage odor pollution.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional view, and FIG. 2 is a sectional view taken along the line A--A in FIG. 1. In the figure, 1 is an impermeable layer, 2 is a landfill site, 3 is a covering material,
3' is a coating, 4 is a waste layer, and 15 is a ventilation standpipe. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. The upper part of a landfill site whose sides and bottom are formed with an impermeable layer is covered with a covering material made of an impermeable material to prevent rainwater from penetrating into the landfill site, and Air is introduced inside the covering material and passed through the waste layer of the landfill site from above to below, thereby aerobically decomposing the organic matter contained in the waste. The leachate produced by decomposition is collected and circulated to the landfill site by sprinkling water from the top of the site to purify it using a trickling filter method using the waste layer as a filter material, resulting in aerobic decomposition of the waste. This is a waste landfill method that is characterized by simultaneously performing wastewater treatment and wastewater treatment. 2. The upper part of the landfill site, which has an impermeable layer on the sides and bottom, is covered with a covering made of an impermeable material to prevent rainwater from penetrating into the landfill site, and to protect the waste layer from the landfill site. A ventilation standpipe with a large number of holes on the outer periphery and an open top is installed inside the coating, and air is introduced into the coating to expand the coating upward, and the ventilation standpipe is opened. through and directly passing air from above to below to aerobically decompose organic matter contained in the waste;
The leachate produced by this decomposition is collected and circulated to the landfill site by sprinkling water from the top surface of the landfill site to purify it using a trickling filter method using the waste layer as a filter material. A waste landfill method that is characterized by performing decomposition and waste treatment at the same time.