WO1989007493A1

WO1989007493A1 - Refuse dump for temporary or permanent disposal of hazardous waste and process for installing refuse dumps

Info

Publication number: WO1989007493A1
Application number: PCT/HU1989/000007
Authority: WO
Inventors: Imre Raabe; Tibor Kuslits; János TUBOLY; József RAPATYI; Gyula Imre; László VARGA; Tamás SCHOLZ; László KOVÁCS; Tamás SCHOLZ, Jr.; László BULIK
Original assignee: "Natura" Környezetvédelmi Tervezo^", Fejleszto^" É; DUNAFERR, Dunai, Vasmu^"
Priority date: 1988-02-16
Filing date: 1989-02-14
Publication date: 1989-08-24
Also published as: EP0362311A1

Abstract

The refuse dump disclosed, comprising a basin (22) partly sunk in the ground (13), several insulating layers and degasing pipes (16), is characterized in that the following layers are superimposed in ascending order: a watertight layer (1), a film (2) for collecting water samples, a basic protective layer (4) consisting wholly or partly of waste to be disposed of, a hydraulically bonded layer (5) consisting partly of waste to be disposed of, a protective film (6), a hydraulically bonded layer (7) consisting partly of waste to be disposed of, which cover the floor and side walls of the refuse dump. Drainage pipes (3) connected to an observation post (14) are provided in the basic protective layer (4). The hazardous waste (8) in the dump is covered, in ascending order, with a protective layer (9), a layer of clay (10) and a layer of humus (11). The refuse dump is bordered by a frame (12) partially sunk in the ground (13). The invention also concerns a process for installing refuse dumps.

Description

Landfill for temporary or permanent storage of hazardous waste and procedures for landfill

The invention relates to a landfill for the temporary or permanent storage of hazardous waste. The invention further relates to a method for the installation of landfills.

In parallel with the development of industry, with the extensive growth of the economy, more and more hazardous waste is being produced, for the temporary or permanent storage of which there are regulations. Appropriate storage is very important because improperly isolated temporary or permanent landfills can wash out the harmful, toxic substances from groundwater and rainwater and then contaminate the environment in a wide area. The soil is unsuitable for agricultural use, the poison penetrates the wells and endangers the drinking water supply for the population. For temporary storage of hazardous waste, pits of appropriate size are dug in the ground. The bottom and walls of the pit are covered with a 30-50 cm layer of clay so that precipitation and groundwater cannot wash out the toxins. After the waste has been stored, the pit is covered with a layer of clay. However, when the temporary storage has ended, not only the originally stored waste, but also the clay that has come into contact with it and thus contaminated must be disposed of in a final storage facility. The final quantity to be stored increases, which increases the investment costs for the final landfill.

Another method is to dig large pools into the ground and line them with concrete; Inner linings are also attached to achieve the prescribed watertightness. This type of landfill is not particularly suitable for temporary storage because it is used for storing the stored substances heavy machinery is used that can easily damage the internal lining. Because of the size of these basins, they are usually not coverable, the waste can be carried away in dust form by the wind or are not protected against rainwater. Any damage to the landfills that have become known so far is determined by taking and analyzing the surface water, groundwater and soil from time to time. It is also known to dig observation wells near the landfill and to examine the groundwater accumulating in them. In this way, however, only the fact of the pollution can be determined, it is not possible to locate the damage. So-called embedding technologies have also become known for the final storage of hazardous waste. According to GB 2 037 734, volatile heavy metal particles are melted down in liquid metallurgical slag after their separation in the cyclone. The cooled, ground slag can be used as road construction material. According to Hungarian Patent No. 130 471, sludge containing heavy metal hydroxides is embedded in concrete and the concrete is used for construction purposes because it has been shown that the embedded metals have not been dissolved out by water or by dilute hydrochloric acid. However, the concrete can only contain 2-5% sludge; ie the method is not suitable for the disposal of large quantities. US Pat. No. 4,432,666 describes an embedding process according to which higher proportions of harmful waste are cured into blocks together with a water-miscible binder. However, these blocks are not used, but are sent to final storage.

In the temporarily or permanently stored Waste can be formed by chemical or biological processes, gases which must be removed. According to the current state of the art, degassing pipes are therefore inserted into the waste in the gas development of a corresponding density; some or all of these tubes are perforated and the gas can escape through them into the atmosphere. This can lead to unpleasant smells and poisoning of the atmosphere. In accordance with the conventional construction of waste landfills, a large pit is dug, on the edge of which solid roads have to be built, designed for considerable loads, on which the vehicles that transport the earth and transport the waste can travel. When the landfill is filled up, the waste is then poured into the pit from above, which fills it from bottom to top. If different types of waste are stored, it is inevitable that they will be mixed in the way described. The purpose of temporary storage now is to temporarily store substances that can later be reprocessed as secondary raw materials (e.g. lean ore and spoil that are stored until a suitable processing method has been developed; coal-bearing rock that can be used when the investment planned for processing has been completed; metal-containing waste, which is dangerous and is still considered environmentally harmful waste, but may already be valuable raw materials for the extraction of these metals in a few n years). Mixed together, however, these wastes are of no use at all.

The object of the invention was to provide a landfill for both the intermediate and the Repository is suitable, offers more security and can absorb much more waste than a conventional landfill of the same size. Any damaged areas should be easy to locate, and if waste is stored that may develop gases, it should be removed.

It was also an object of the invention to develop a method for the creation of landfills with which landfills can be created in such a way that no road construction is necessary, furthermore the separate storage of different waste is made possible and, above all, the amount to be stored with the same footprint on at least double can be increased. The invention is based on the knowledge that the amount of waste that can be stored can be increased, on the one hand, by using embedded waste in addition to other materials to build the landfill itself. Furthermore, according to the invention, it was recognized that it is easier and cheaper and leads to an increase in the amount of waste that can be stored if, instead of filling up the landfill from solid streets from above, a provisional route is created within the landfill from reusable elements and the landfill first on the right and to the left of the path and, after continuing on the path, also fills its area.

The invention accordingly relates to a landfill for the temporary or permanent storage of hazardous waste with a pool partially submerged in the ground, several insulating layers and degassing pipes. It is characteristic of the landfill according to the invention that the following layers: waterproof layer, water collecting foil, basic protective layer, consisting partly or entirely of waste to be stored, hydraulically bound layer, partly consisting of waste to be stored, - protective film, hydraulically bound layer, partly consisting of waste to be stored, covering the floor and the side walls of the landfill, in the basic protective layer drainage pipes connected to an observation stand are provided, the hazardous waste in the landfill is covered from above with a protective film, a layer of clay and a layer of humus, and the landfill is surrounded by a frame that is partially recessed into the ground.

According to one embodiment of the invention, the basic protective layer consists wholly or partly of lime powder, calcareous slag or other calcareous waste.

According to a further embodiment of the invention, the hydraulically bound layers contain hazardous waste to be embedded in hydraulic or quasi-hydraulic binders such as cement or fly ash.

A further embodiment of the invention provides in the degassing pipes a filling which is suitable for absorbing the gases escaping from the landfill on a perforated base. Finally, according to a further embodiment of the invention, the observation stand contains a signal unit.

The invention also relates to a method for creating waste disposal sites. For the procedure is It is characteristic that, when carrying out the earthworks, between two trench-shaped landfill basins, a route that exceeds the sole height is left, after laying the walls and floor insulating foils and layers on the route, a provisional road consisting of repeatedly usable elements is created, from which this road is used Transport vehicles first fill up the trench-shaped landfill basins on the right and left of the road, then collect the elements that can be used repeatedly between the filled sections of the landfill basins and also fill up the space between the filled landfill basins.

A preferred embodiment of the method consists in using blocks made of concrete and waste embedded in these as repeatable elements.

It is also preferred to cover the sections of the landfill basin that are currently being filled in and the provisional street with a mobile film tent.

Finally, in order to make it possible to store different types of waste separately, it is preferable to divide the landfill basin into several sections by pulling in partition walls or foils extending perpendicularly to the longitudinal axis of the trench-shaped landfill basins.

The invention is explained in more detail with reference to the accompanying drawings.

Fig. 1 shows the landfill according to the invention in

2 shows a similar cross section with a degassing tube, 3 illustrates the usual cross section of a known landfill, and FIG. 4 shows in cross section a landfill that was created using the method according to the invention,

As can be seen from FIG. 1, the bottom layer of the landfill according to the invention is a waterproof layer 1 covering the profile formed in the bottom 13, the sealing ability of which should be at least 10 ^-6 cm / h. This layer is expediently applied after the floor has been tamped with slurry clay. However, it is also possible to waterproof the floor using the methods described in the specialist literature. In the case of temporary storage, the waterproof layer 1 can also be omitted, its function being taken over by the film 2 collecting water samples. The film 2 collecting water samples has the task of preventing the contaminated water which escapes in the event of damage to the landfill from seeping into the ground. The film 2 must be strong enough to withstand the mechanical stress that occurs during installation. Strong plastic films are particularly suitable.

The film can be laid after the earth profile has been formed, but it is more practical to roll out the film a little further as the earthworks progress.

As a further safeguard, which is not known in conventional landfills, the landfill according to the invention has a basic protective layer 4 above the film 2 collecting water samples, which consists entirely or partly of substances which also have to be deposited somewhere because they are considered hazardous industrial waste. This layer serves as a protective wall when overlying it further layers of the landfill should become defective. The leachate is almost always acidic, so it is neutralized in the basic layer 4. The basic protective layer 4 can be applied, for example, from lime-containing metallurgical slag considered waste in industry, from lime powder or other lime waste. These substances would have to be deposited somewhere anyway, and if they are used to build the preferably 5-30 cm thick basic protective layer 4, the landfill of the lime waste need not be taken care of otherwise.

A drainage pipe 3, which is connected to an observation stand 14, runs in the basic protective layer, closely above the film 2 collecting water samples. The drain pipe 3 is perforated and, as a result, is able to absorb the water that seeps into the drain pipe 3 from the lower layer of the basic protective layer 4 and to pass it on to the observation station. The drain pipe 3 is divided into sections, from each section a separate line leads to the observation stand 14. If the landfill becomes defective anywhere, the contamination appears only on the discharge line of the pipe section which runs under the damaged point. In this way, a possible damage location can be quickly located at the observation stand 14.

A hydraulically bonded layer 5 is connected to the basic protective layer 4. Because this hydraulically bound layer 5 is also partly created from waste, further considerable amounts of waste can be built into the wall of the landfill. For this purpose, the waste is embedded in hydraulic or quasi-hydraulic binders (cement, fly ash) or in water-glass containing masses. The technology of embedding is known per se. The harmful free ions are integrated into the molecular lattice of the concrete and cannot be washed out. In the iron industry, there is a large amount of molding sand waste that contains phenol / formaldehyde, urea / formaldehyde or furan resin from the foundry molding. This resin-containing sand can be processed together with hydraulic or quasi-hydraulic binders and fillers into plates and then to

Construction of the hydraulically bound layer 5 can be used. It is also possible to pour the layer as a coherent layer from the mixed concrete.

The hydraulically bonded layer 5 is followed by a protective film 6, for the material and laying of which the statements made in connection with the water samples 2 apply.

In addition, the protective film 6 must be resistant to acids, because any leachate that penetrates the upper layer is almost always acidic. The protective film 6 is expediently made of rubber or plastic.

A further hydraulically bound layer 7 is provided above the protective film 6, the structure of which is the same as that of the hydraulically bound layer 5. The two hydraulically bound layers 5 and 7 enable the storage of considerable amounts of waste without the actual storage capacity being used thereby becomes.

The hazardous waste 8 is poured onto the hydraulically bound layer 7. The waste can be compacted and / or dewatered in a known manner before it is stored, whereby its space requirement is reduced. If it is the mechanical properties that Allow consistency of waste 3, the landfill can also be filled beyond the height of its sides, creating a hill with a sloping slope. This leads to a further increase in storage capacity. The waste 8 is covered by sine protective film 9, which suitably consists of plastic or rubber. In order to protect them from mechanical influences and solar radiation, an appropriately 10-50 cm thick layer of clay 10 is provided above it and an expedient 5-30 cm thick humus layer 11 is provided above it.

The humus layer 11 is expediently planted with grass because this catches the rainwater and protects the humus layer 11 from erosion. In the event of final storage, more permanent plantings are also possible, the landfill blends in with the landscape as a green hill.

The landfill is enclosed by a fixed frame 12. This is designed so that the sides of the protective films 6 and 9 can be attached in a watertight manner to its edge which projects above the floor level. The protective film 6 is expediently beyond the upper part of the frame 12 and can be turned over to the outside. The protective film 9 is performed similarly; it is knocked over the edge of the frame 12 above the hydraulically bound layer 7. In this way, rainwater cannot enter the edge of the landfill. The frame 12 can also be made from concrete elements in which hazardous waste has been embedded. 2 shows the cross section through a landfill according to the invention which has degassing pipes 16. As already mentioned, these degassing pipes serve to discharge gases formed in the landfill into the free atmosphere. According to the invention Degassing pipe 16 in individual sections or over its entire length, a filling 17, which is arranged on a perforated plate 18, expediently a sieve insert. This filling is suitable for the absorption of the gases formed; depending on the type of waste, the appropriate filling must be selected. Taking into account that the escaping gases can be, for example, hydrogen sulfide and hydrogen cyanide (the latter, for example, when disposing of salt baths originating from the hardening shop), this measure according to the invention is of great importance. The gas discharge pipes 16 can be provided with a hood 19 to protect the filling 17. The perforation of the degassing pipes consists of openings of 2-3 cm, which can be covered with a sieve, which allows the gases to pass through but does not block the openings. The filling can consist of limonite or lime, for example, but the choice of filling always depends on the type of waste.

It can also be seen from FIG. 2 that the observation stand 14 can be equipped with a signal unit 15. The signal unit contains a measuring device for each of the separately guided sections of the drainage pipe 3. Any parameter that changes significantly in the case of leachate is suitable for measurement. For example, it is possible to measure the conductivity of the water. In this case, it is advisable to set a limit value that depends on the salinity of the groundwater. If the landfill is damaged and soluble ions in the leachate appear, the conductivity of the water coming from the relevant section of the drainage pipe 3 suddenly increases. If the set value is exceeded Limit value, an optical and / or acoustic signal is triggered.

3 and 4 serve to explain the method according to the invention. 3 shows the cross section of a conventional landfill basin. In addition to the basin, the transport routes 24 run from concrete, on which the waste to be stored is approached. Fig. 4 shows the creation of a landfill according to the inventive method. When carrying out the earthworks, a route 23 is left between two trench-shaped landfill basins 22. As the earthworks progress, elements 20 that can be used repeatedly are laid on the route, which form a provisional road 21 running on the route. This is where the goods to be stored move later

Material approaching vehicles. The waste 8 is unloaded and piled up on both sides of the provisional street 21. When the spaces labeled I in Fig. 4 are filled, the reusable elements are collected one by one (imagine the vehicle is approaching the viewer in reverse gear) and after a portion of the provisional Strasss 21 has been dismantled, the filling of room II can begin. It is already readily apparent from FIG. 4 alone that the amount of waste to be stored can be at least doubled in this way.

It is preferred to make the reusable elements 20 from concrete and hazardous waste embedded in the concrete. Dis are appropriate

Elements as long as the street is wide (e.g. 2-3 m), 40-50 cm wide and 20-30 cm thick. Elements of this size withstand the weight of the work machines and can be easily moved with a crane car (when laying or dismantling the provisional street). It is further preferred to cover the section of the landfill just being filled up and the provisional street 21 with a mobile film tent so that the uncovered waste is not carried away by the wind or drenched by rainwater.

Since the trench-shaped landfill basins 22 are not filled up from the bottom up, but in the longitudinal direction in the manner described, there is a natural possibility for the separate storage of different waste. If a certain type of material to be stored is no longer or temporarily no longer present, an intermediate wall or film that extends over the entire cross section and runs perpendicular to the longitudinal axis of the trench-shaped dumping basin 22 is drawn in and the dumping pool is thus divided into departments. This is important in the case of temporary storage, because the stored substances can only be worked up by separate storage. The dismantling of the landfill, the removal of the temporarily stored waste takes place in reverse order. The cover layers are removed and then the waste is first loaded onto vehicles on route 23. Reusable elements 20 are placed on the step-by-step route, and the machine moves forward a little.

The type of procedure described has numerous and serious advantages: no road construction required, the parent duck can be reused as often as required; more than double storage capacity; Possibility of expansion by additional, parallel landfill basins; it is not necessary to build the whole system at once, but the speed of construction (and therefore the necessary investments) depend on the amount of waste to be stored. With the described method, not only the landfills according to the invention for hazardous wastes can be created, but landfills for any wastes or stockpile materials.

Claims

1. Landfill for the temporary or permanent storage of hazardous waste with a pool partially submerged in the ground (13), several insulating layers and degassing pipe (16), characterized in that the following layers are successively from bottom to top: waterproof layer (1), - collecting water samples Foil (2) basic protective layer (4), consisting entirely or partly of waste to be stored, hydraulically bound layer (5), partly consisting of waste to be stored, - protective film (6) hydraulically bound layer (7), partly from. waste to be stored, covering the floor and the side walls of the landfill, in the basic protective layer (4) with drainage pipes (3) connected to an observation stand (14) are provided, the hazardous waste (8) in the landfill from above with a protective film (9) , a layer of clay (10) and a layer of humus (11) are covered and the landfill is surrounded by a frame (12) partially recessed into the soil (13).

2. Landfill according to claim 1, characterized in that the basic protective layer (4) consists wholly or partly of lime powder, calcareous slag or other calcareous waste.

3. Landfill according to claim 1, characterized in that the hydraulically bound layer (s) (5 and / or 7) in hydraulic or quasi-hydraulic binders such as cement, fly ash, etc. Contains embedded hazardous waste, such as phenol / formaldehyde, urea / formaldehyde, furan resin-containing foundry sand.

4. Landfill according to claim 1, characterized in that the (dis) degassing pipe (s) (16) contains (contain) a filling (17) suitable for absorbing the gases escaping from the landfill on a perforated base (13).

5. Landfill according to claim 1, characterized in that the observation stand (14) is equipped with a signal unit (15).

6. A method of creating and filling up waste landfills, characterized in that when carrying out the earthworks between two trench-shaped landfill basins, a route exceeding the level of their sole is left, after laying the walls and floor insulating foils and layers on the route one from repeatedly usable Creates an existing provisional road, from which the transport vehicles traveling on this road first fill the trench-shaped landfill basins to the right and left of the road, then collect the elements that can be used repeatedly between the filled sections of the landfill basins and also fill the gap between the filled landfill basins.

7. The method according to claim 6, characterized g e k e n nz e i c h n e t that is used as repeatable elements made of concrete and existing in these embedded blocks blocks.

8. The method according to claim 6 or 7, characterized in that one covers the section of the landfill basin that is currently being filled in and the provisional street with a mobile film tent.

9. The method according to any one of claims 6-8, characterized g e k e n n z e i c h n e t that one divides the landfill basin into several departments by pulling in perpendicular to the longitudinal axis of the trench-shaped landfill basin, extending over the entire cross-section partition walls or foils.