KR20010100077A - Stabilization, excavation and screening methods for the maintenance and restoration of unsanitary landfills - Google Patents

Abstract

The present invention can maintain and restore an unsanitary landfill that has been left as a pollution source and can be recycled into useful land (sites, flower gardens, barns, farmland, parks, sports facilities, parking lots, etc.). Leachate flowing out of the unsanitary landfill is increasing soil contamination as well as groundwater and surface water pollution. In order to fundamentally remove such contaminants, the present invention comprises the steps of installing a landfill gas collecting pipe and an air supply pipe selectively according to the landfill site conditions, and rapidly stabilizing by injecting microorganisms and air; Digging the landfill waste to sort coarse particles and recycled waste; Screening the soil using a rotating screen; Separating flammable and non-flammable from the roller screen and separating and compressing vinyls by wind power at the rear end; Thermal desorption step of the separated sediment and ground contaminated soil according to the contamination state; Using a bioreactor (drum bioreactor) to adjust the pH and moisture, and the reaction of new microorganisms (bacillus khr-10-mx, etc.) and nutrient minerals from the biological soil purification step; After the maintenance and restoration of the unsanitary landfill is completed, the purified soil can be reclaimed or recycled as cover material. Therefore, it is possible to recycle the reclaimed and reclaimed landfills into useful land (sites, flower gardens, barns, farmland, parks, sports facilities, parking lots, etc.) and to prevent environmental pollution.

Description

Stabilization, excavation, and screening methods for treating and restoring unsanitary landfills

[Industrial use]

The present invention relates to a rapid stabilization, excavation and screening method and a method for purifying sediment and contaminated soil in the maintenance and restoration of an unsanitary landfill. More specifically, the landfill waste is excavated and screened to remove the source of contamination, and Provides a method for the purification and maintenance of contaminated soils using thermal desorption or biological treatment processes and the recycling of reclaimed landfills back into useful land.

[Prior art]

Various wastes and industrial wastes, which constitute the largest part of the environmental pollution source, are finally landfilled and then changed and transformed through various media such as water, soil, and atmosphere, and continue to change and transform soil contamination, groundwater pollution and odors. By affecting natural ecosystems, including humans. However, the damage caused by soil-mediated soil pollution is relatively slower than the damage caused by water quality and air pollution, and the delivery route is complicated. Therefore, the treatment technology has not been established.

Therefore, the conventional techniques for purification of contaminated soil are classified into physicochemical treatment technology, thermal treatment technology, and biological treatment technology. If the treatment method is classified in detail, in-situ physiccal / chemical treatment includes Air Injection (soil vapor extraction, air sparging), Steam / Hot Air Injection, Electrical Thermal Injection, Soil Flushing method and underground biological. In-situ bioremediation includes bioventing, biopiling, bioaugermentation, biostimulation, and ex-situ treatment, such as bioreactor and soil washing. Specifically, the physicochemical treatment technique is soil vapor extraction (SVE). The principle is to artificially induce the flow of air in the pollution site to evaporate the harmful compounds remaining in the pores of the soil. At this time, the injection hole and the extraction hole are used. Through this process, contaminants are transferred from the soil to the air, and the contaminated air is discharged into the atmosphere through a post-treatment process. Another thermal treatment technique involves injecting contaminated media, mainly by VOCs, SVOCs, PCBs and pesticides, into rotary dryers, heated screws, fluidized bed dryers and heating them to temperatures above which they can volatilize contaminants. Is a physical treatment that physically separates contaminants from one phase to another. Another biological treatment technique is bioremediation, in which a plurality of injection holes are installed in a contaminated site and microorganisms and nutrients are locally injected to decompose organic pollutants.

Therefore, although patents and utility models have been reported in Korea, many of them are used for oil-contaminated soils and heavy metal-contaminated soils. Biological purification of oil-contaminated soils using petroleum crab hydrocarbon-decomposing microbial preparations of Korea Patent Publication No. 2000-0034035 Method, and above-ground high-floor pile purification device for oil and organic contaminated soil by micro-pneumatic automatic control method of soil void of Korea Utility Model Registration No. 20-0224012, and water-soluble and biodegradable metal of Korea Patent Publication No. 1999-0041211 Soil purification method using ion trapping agent, method of purifying contaminated soil of Korean Patent Publication No. 10-1998-002207, biological treatment method and apparatus of contaminated soil of Korean Patent Publication No. 10-1997-070163, and Korean patent Purification of contaminants by halogenated organic compounds of Publication No. 10-2000-070829 Method, and the method and device for the treatment of landfill waste and contaminated soil of Korea Patent Publication No. 10-1995-703105, and the sorting device comprises waste landfill sorting device of Korea Utility Model Publication No. 96-610, Landfill waste sorting device of Korea Patent Publication No. 2000-0058670, excavated waste sorting device of Korea Patent Publication No. 1999-0078791, unsanitary waste landfill of Korea Patent Publication No. 2000-0031010 and stabilization The method discloses a method of stabilizing a waste landfill site using aerobic microorganisms of Korean Patent Publication No. 1997-0073758 and a method of stabilizing garbage for restoring a landfill of Korea Patent Publication No. 1999-006333. The soil purification method is limited to oil pollution or heavy metal contaminated soil, and the stabilization method is not only able to remove the source of pollution, but also requires a long treatment time, there is a technical and economic limitation to apply to domestic unsanitary landfill. Therefore, in the technology capable of maintaining and restoring from stabilization to soil purification in a one-stop manner, the above-mentioned conventional techniques have different unit processes and treatment methods, and each has a technical and economic limitation in maintaining and restoring an unsanitary landfill. There was not suitable.

In Korea, the lack of knowledge and experience in the maintenance and restoration techniques of unsanitary landfills is insufficient to develop the treatment technology, and it is difficult to apply foreign technologies to the maintenance and restoration of unsanitary landfills in Korea. The processing cost is expensive.

Therefore, the present inventors combined with partial process technology according to landfill site maintenance and restoration technology, which is novel and advanced compared to the prior art, and employs about 1000 pieces that have been left in Korea using rapid stabilization, excavation, screening processes and thermal desorption or biological treatment methods. The present invention has been completed by developing a technology that prevents environmental pollution while maintaining and restoring a poor landfill and recycling useful narrow land (sites, sports facilities, parking lots, flower gardens, barns, farmland, etc.).

The present invention is to excavate and select the waste from the rapid stabilization and simultaneous LFG treatment in order to fundamentally remove the soil contamination and groundwater contamination by leachate continuously discharged from the unsanitary landfill, and biologically treat the selected contaminated soil It is intended to provide a method for cleanup to a level that can be recycled in a short time and ultimately to recycle the reclaimed landfill into useful land (sites, flower gardens, barns, parks, sports facilities, parking lots, etc.).

1 is a process chart of the stabilization, excavation, screening method and the screening soil and contaminated soil biological purification method in the maintenance and restoration of unsanitary landfill according to Example 1 of the present invention,

2 is a schematic diagram of an example of rapid stabilization and LFG treatment used by Example 1 of the present invention,

3 is a schematic diagram of an example of stabilization and excavation used by Example 1 of the present invention,

4 is a schematic diagram of an example of a bioreactor used by Example 1 of the present invention.

<Description of the code | symbol about the principal part of drawing>

1: LFG collection tube 2: air injection tube

3: condenser 4: booster

6: biofilter 7: gas incinerator

8: gas tank 9: blower

10: new strain injection device 11: landfill waste

100 bioreactor drum 101 temperature controller

102: rotary regulator 103: ceramic heater

104: acid substrate 105: strain injection port

106: exhaust gas line 107: blower

108: flow meter 109: filter

110: washing machine 111: adsorption filtration tower

112: contaminated soil

[Means for solving the problem]

In order to achieve the above object, in one aspect of the present invention,

(1) installing a landfill gas collection pipe and an air injection pipe generated from the landfill waste in the landfill; Wow

(2) digging the landfill waste to selectively separate the coarse particles and the non-combustible waste and transport them to the belt conveyor; Wow

(3) separating the earth and vinyl components by passing the excavated waste through a rotating screen; Wow

(4) separating the incombustible and combustible wastes through the roller screen and separating the vinyls by the wind at the rear end; Wow

(5) the separated vinyls are compressed or melted to reduce the volume and refilled or incinerated; Wow

(6) Excavation and sedimentation of contaminated soil in separated sediment and landfill here, pH 7-8, temperature 20-50 ℃ and humidity 40-40% The present invention provides a method for maintenance and restoration of an unsanitary landfill, which includes decomposing and removing contaminants in the soil.

Hereinafter, the present invention will be described in more detail.

In addition, the present invention divides the landfill site with a grid network in order to maintain and restore the landfill site to recycle useful land, and install the LFG collection pipe (1) and the air injection pipe (2). Depending on the state of the landfill site, the microorganism and nutrient minerals of the new strain are selectively injected into the air inlet tube from the new strainer injection device 10 to achieve rapid stabilization. The collected LFG (landfill gas) is incinerated gas incinerator (7) according to the state or remove the odor through the biofilter (6).

After excavating the landfill waste from a certain area of the landfill, the undisassembled coarse particles, non-combustible and recycled wastes are sorted and transported into a belt conveyor to sort out soil from 25 to 50 mm in a first stage rotating screen. Again sift 25 to 35 mm of soil on a two-stage rotating screen. In order to continuously separate the non-combustible and combustible wastes, the primary roller screen is used to separate the high specific gravity nonflammable waste and the low specific gravity combustible wastes by wind and then remove the rollers again from the secondary roller screen. After the passage, it is separated by wind again. Sorted vinyls are compressed or melted to reduce volume and incinerate or landfill. The sorted soil separated from the rotating screen and the roller screen is recycled as landfill or cover material after removing various contaminants through thermal desorption or bioreaction process according to the contaminated state.

Subsequently, thermal desorption or bioreaction of organic contaminants such as pesticides, volatile organic compounds (VOC, SVOCs), and polychlorinated biphenyls contained in the excavated contaminated soil separately from the pretreated soil Decompose to remove.

In the thermal desorption process, the contaminated soil is heated at a temperature at which contaminants can be volatilized in the contaminated soil, for example, 150 to 350 ° C., to desorb and remove various contaminants in the contaminated soil by vaporization or thermal oxidative decomposition.

In the bioreaction process, conditions for microbial growth of the pretreated screened soil and contaminated soil, for example, pH 7 to 8, humidity of 40 to 50%, and temperature of 20 to 50 ° C., may be decomposed. New microorganisms present, oxygen and various nutrients necessary for respiratory growth of these new microorganisms are supplied and reacted with contaminated soil to biologically decompose and remove contaminated organic substances and heavy metals in contaminated soil. In this process, contaminated organics in contaminated soil are fed and the oxygen supplied is rapidly decomposed and consumed by the respiratory activity of aerobic and anaerobic microorganisms to produce CO ₂ , H ₂ O, lower hydrocarbons and heat. A microorganism that can be used in the present invention include Bacillus subtilis (Bacillus subtilis), Bacillus poly miksa (Bacillius polymyxa), also Pseudomonas (Rhodopseudomonas), auto tropic bakteo (Autotrophic bacter), Pseudomonas (Pseudomonas), nitro bakteo (Nitro bacter ), Trichoderma viride , Cellulomonas sp., Actinomyces , Filamentous fungi , and may be used in combination of two or more thereof. New strain Bacillius sp. khr-10-mx (KICTC 8533P, Korea Research Institute of Science and Technology), Cellulomonas sp. It is preferable to use khr-15-mx (KICTC 8534P) and complex strain khr-5-mx (KICTC 0078BP, Korea Institute of Science and Technology) alone or in combination.

In this way, by purifying the contaminated soil of landfills, contaminated unsanitary landfills can be recycled into useful land (sites, flower gardens, farmland, barns, parks, sports facilities, parking lots, etc.) and environmental pollution can be prevented.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited to these, and it is obvious to those skilled in the art.

Example 1

In the present invention, in order to achieve the above object, an unsanitary landfill is maintained and restored. In the non-sanitary landfill maintenance and restoration method, it will be described with reference to the accompanying drawings, the technical idea. FIG. 1 is a process chart showing the stabilization, excavation, and screening methods for treating and restoring unsanitary landfills and the method for screening soils and contaminated soils according to the first embodiment of the present invention. FIG. 2 is an embodiment of the present invention. FIG. 3 is a schematic diagram of an example of rapid stabilization and LFG treatment used by Example 1, and FIG. 3 is a schematic diagram of an example of stabilization and excavation used by Example 1 of the present invention, and FIG. 4 is an embodiment of the present invention. Schematic of one example of a bioreactor used in Example 1.

1) Rapid stabilization and landfill waste excavation, transportation and input

In order to process the gas generated in the landfill, it is divided into a certain width and depth, and the LFG (landfill gas) collecting pipe 1 and the air inlet pipe 2 are installed, and stabilization is performed in the aeration area. Simultaneous excavation in the excavation area (excavation area), it can be rapidly stabilized by injecting the microorganism and nutrient minerals from the new strain injection device 10 through the air injection pipe (2) and injecting air. Therefore, the collected gas is incinerated in the gas incinerator 7 or the odor is removed using the biofilter 6 according to the state.

Here, while stabilizing simultaneously, the landfilled waste is excavated with an excavator, etc. to sort coarse waste, and the conveyor is transported to the next process.

In addition, in order to prevent odor and scattering dust that may occur during the excavation process, the new strains of microorganisms were sprayed to prevent odor and dust scattering.

2) 1, 2 stage rotating screen sorting and 1, 2 stage roller screen and wind sorting

Excavated waste is put into the screen rotating body through the garbage input conveyor, and soil (25 ~ 50mm) and small particles are discharged to the lower part of the rotating screen in the first stage rotating screen which performs the first-order screening function. Transfer to heat desorption system or bioreaction system.

Here, the foreign material is removed while rotating and falling on the first stage rotating screen and automatically transferred to the second stage rotating screen. Garbage from which more than 80% of the soil is removed from the first-stage rotating screen is introduced into the second-stage rotating screen and is rotated while the tangled or agglomerated wet rubbish is unwound by the rotating screen arm, and the non-combustible waste of 25 to 35mm or less is removed. The sediment, steel, glass, plastics, and vinyls, which are dropped to the soil transfer conveyor and are not separated until the end, are sorted by passing through a roller screen consisting of one and two stages.

As more than 50mm of trash passes through the roller screen, as soon as the trash falls, the wind is sorted according to the blower. The non-combustible trash falls by the specific gravity, separated and transported into the non-combustible trash conveyor, and the vinyls are separated into the combustible trash by the wind.

Vinyls that make up the main species are compressed or melted to reduce the volume and then incinerated or refilled.

In this example, the combustible and incombustible composition ratios of the landfill wastes of landfill B and landfill D were investigated.

The composition of combustible waste was 26.3% (vinyls, rubbers, etc.), 3.6kg, and the composition of noncombustible waste was 73.7% (earth, glass, bottles, concrete, etc.) and 12.6kg.

3) Purification of contaminated soil by thermal desorption process

Waste excavated at the landfill was passed through a rotating screen to separate contaminated soil. Subsequently, the thermal desorption process was performed using the rotary thermal desorption apparatus. First, the contaminated soil was introduced into the inlet of the rotating drum consisting of a horizontal cylindrical, using a conveyor. The heating burner was heated to maintain 150 to 350 ° C., and the oxidizer was thermally oxidatively decomposed by transferring heat directly or indirectly into the drum while rotating the drum by interlocking a reduction gear and a cylindrical rotating gear attached to the rotating drum.

The removal rate of the contaminated organic material according to the rotational speed and temperature of the contaminated soil was measured by the soil pollution test method and is shown in the following [Table 1].

TABLE 1

4) Purification of contaminated soil by bioreaction process

Excavators are responsible for the contaminated soil and waste from S landfill (used as landfill for 15 years), D landfill (used as landfill for 1 year and 5 months), K landfill (used as landfill for 7 years), and B landfill (used as landfill for 17 years), respectively. Coarse particles were screened in the same manner as in Example 1, and earth and sand were sorted by wind through a rotating screen and a roller screen.

Subsequently, the selected contaminated soil 112 is introduced into the bioreactor 106 shown in FIG. 3, and the temperature of the bioreactor is maintained at 30 to 50 ° C. with the ceramic heater 103 of the temperature controller 101. The pH of the strain was adjusted to 7 to 8, and the humidity was adjusted to 40 to 50%. Bacillus sp. khr-10-mx (KICTC 8533P) and complex strain khr-5-mx (KICTC 0068BP) were selected from 1 to 3 m3 of selected soils. 50-100 g of nutritional minerals were added to the input port 105. The fresh air by the blower 107 is passed through the filter 109 while controlling the air flow rate to the flow meter 108 to be supplied through the acid substrate 104, and the bioreactor 100 is operated using the rotation controller 102. The biological reaction proceeded while rotating at 5 to 17 rpm. The generated gas was discharged through the exhaust gas line 106 to be exhausted through the exhaust gas cleaner 110 and the adsorption tower 111.

The dominant species microorganism and the decomposition mechanism in the bioreactor 100 are shown in the following scheme.

(Carbohydrate Breakdown)

Bacillus subtilis secretes amylase, which breaks down carbohydrates, and breaks down carbohydrates into 6% Glucose, 30% Maltose, and 64% Dextrin. Ingestion of monosaccharides divides, multiplies and continues to secrete Amylase, which eventually becomes a food for microorganisms and breaks down into water (H ₂ O) and carbon dioxide (CO ₂ ).

Scheme Ⅰ

C ₆ H ₁₂ O ₆ → 6CO ₂ + 6H ₂ O + 685.5Kcal

(Protein breakdown)

Protease, a proteolytic enzyme, is secreted from Bacllus subtilis and Bacillus polymyxa to change proteins into easily digestible amino acids, and the amino acid containing the changed N-group becomes a basic food for the proliferative growth of Bacillus subtilis and Bacillus polymyxa. Ingestion of amino acids breaks down growth and continues to secrete protease. Eventually, amino acid-based materials are fed and decomposed by microorganisms to form water (H ₂ O) and carbon dioxide (CO ₂ ) ammonia.

Scheme II

(Lipid breakdown)

Rodopseudmonss genus and Bacillus licheniformis secrete Lipase to break down fats into alcohols and fatty acids so that alcohol and fatty acids become food for microorganisms, and microorganisms continue to multiply by feeding alcohol and fatty acids and secrete Lipase. Eventually alcohols and fatty acids are broken down by microorganisms into water (H ₂ O) and carbon dioxide (CO ₂ ).

Scheme Ⅲ

(Decomposition of Hydrogen Sulfide Gas (H ₂ S))

It is converted into HO ₄ by Beggiatoacea, an autotrophic bacterium, and removes the odor of H ₂ S gas.

Scheme IV

H ₂ S + H ₂ O → H ₂ ↑ + H ₂ SO ₄

(Decomposition of ammonia)

Nitrobactor, Pseudomonas converts ammonia (NH ₃ ) into NO ₂ and eventually releases NO ₃ to N ₂ gas to eliminate odors and irritants caused by ammonia.

Scheme V

(Disassembly of Cellulose)

Cellulose is a strong secretion of Cellulase C ₁ enzyme by Tricchoderma viride, attacking the molecular structure of the amorphous part of the cellulose, a polymer carbohydrate structure, and breaking the link, the crystal part is decomposed by Cellulase Cx enzyme again It is easily converted to monosaccharides. Monosaccharides are again hydrolyzed by microorganisms and most of the carbon remains corroded.

The removal rate of contaminants in the contaminated soil over time in each test group was measured by the soil contamination test method and is shown in the following [Table 2].

TABLE 2

In this invention, in order to achieve the objective mentioned above, the unsanitary landfill was repaired and repaired.

The present invention can prevent and prevent environmental pollution by maintaining and restoring an unsanitary landfill to prevent the spread of leachate contamination and to purify contaminated soil.

In addition, it is possible to maximize the use of the land by recycling the reclaimed landfills into useful land (sites, flower gardens, barns, parks, sports facilities, parking lots, etc.).

Claims (4)

In the method of stabilization, excavation and selection in the maintenance and restoration of unsanitary landfill, and the method of purifying sediment and contaminated soil, Partitioning the landfill with a grid to install an LFG collection tube and an air inlet tube, and injecting only microbial microorganisms and nutrient minerals or air to rapidly stabilize biologically; Wow Collecting LFG to remove odors from the incineration or biofilter in the gas incinerator according to the concentration; Wow Excavating the landfill waste from the excavation zone to selectively separate coarse particles and non-combustible waste, and transport and input by a belt conveyor; Wow Sorting and separating the contaminated soil and vinyl through the first step rotating screen and the second step rotating screen; Wow Screening and separating the vinyl and non-combustible wastes by wind at the rear stage from the process of separating the combustible and non-combustible mixed waste by the first and second roller screens; Wow Excavate and filter contaminated soil in selected soil or landfill, adjust pH 7 to 8, temperature 20 to 50 ℃ and humidity to 40 to 50% according to the contaminated condition, and rapidly bioreact by adding microorganisms and nutrient minerals. Biologically contaminated soil purification step of removing various contaminants contained in the soil from the activated microorganisms; Containing The method characterized in that the maintenance restoration of the sanitary landfill from the process of the soil purification step in the stabilization step is completed The method of claim 1, Bacillus sp. khr-10-mx, Cellulomonas sp. at least one of khr-15-mx and complex strain khr-5-mx. The belts, which are the means of transporting the excavated waste, the rotating screen as the primary separation device, the roller screen as the secondary separation device, the blower and the dustproof membrane, etc. Or excavation and screening of an unsanitary landfill, characterized in that the volume is reduced by melt treatment and refilled or incinerated. Selective soil and contaminated soil are selectively purged from a thermal desorption process or a bioreaction process depending on the contaminated state and reclaimed or recycled into cover material.