• Journal of the Korean Society of Groundwater Environment
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• v.4 no.4
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• pp.185-190
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• 1997

Electrical surveys were conducted at the Seokdae waste landfill in July,1996. Within the landfill, 4 lines of dipole-dipole surveys and 7 Schlumberger soundings were carried out and 2 soundings in front of the landfill. In the landfill, interpretations of the survey data show low resistivity zones below 10 Ωm to a depth of 50 m from the surface and such low resistivity zones of the D block are thicker than those of the other blocks by about 2~10 m. Considering the depth of the bedrock and the height of waste reclamation, no evidence of bedrock contamination by leachate is indicated. But it is inferred that the weathered zones are contaminated in the landfill. In the block A and B, minor fault having the strike of N$70^{\circ}$W have been confirmed by dipole-dipole surveys, so future contamination of the bedrock by leachate is possible The degree of ground contamination is the highest in the D block due to the leachate plume mainly heading for this block. On the other hand, electrical soundings do not indicate ground contamination by leachate in the front area of the landfill.

• Journal of Soil and Groundwater Environment
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• v.29 no.4
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• pp.1-11
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• 2024

This study evaluated a method for prompt and periodic monitoring of moisture content in the waste layer of a landfill using a Time Domain Reflectometry (TDR) sensor, aimed at ensuring the stable operation of the bioreactor facility at the 2nd landfill of the SUDOKWON Landfill Site. It was found that the TDR sensor is sensitive to variables such as temperature changes and ion content in both the waste layer and leachate, indicating that a correction equation is necessary. A correction equation derived through regression analysis demonstrated a high correlation (correlation coefficient = 0.9647), and field verification experiments confirmed its reliability with an average deviation of only 1.5%. This verifies that the TDR sensor is effective for measuring and monitoring moisture content in landfills. It is also anticipated to be useful for various applications, including monitoring leachate levels, detecting leachate leakage, and assessing rainwater infiltration.

• Advances in environmental research
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• v.10 no.1
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• pp.59-86
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• 2021

Landfilling is the most commonly adopted method for a large quantity of waste disposal. But, the main concern related to landfills is the generation of leachate. The leachate is high strength wastewater that is usually characterized by the presence of high molecular recalcitrant organics. Several conventional methods are adopted for leachate treatment. However, these methods are only suitable for young leachate, having high biodegradability and low toxicity levels. The mature and stabilized leachate needs advanced technologies for its effective treatment. Advanced oxidation processes (AOPs) are very suitable for such complex wastewater treatment as reported in the literature. After going through the literature survey, it can be concluded that Fenton-based approaches are effective for the treatment of various high/low strength wastewaters treatment. The applications of the Fenton-based approaches are widely adopted and well recognized due to their simplicity, cost-effectiveness, and reliability for the reduction of high chemical oxygen demand (COD) as reported in several studies. Besides, the process is relatively economical due to fewer chemical, non-sophisticated instruments, and low energy requirements. In this review, the conventional and advanced Fenton's approaches are explained with their detailed reaction mechanisms and applications for landfill leachate treatment. The effect of influencing factors like pH, the dosage of chemicals, nature of reaction matrix, and reagent ratio on the treatment efficiencies are also emphasized. Furthermore, the discussion regarding the reduction of chemical oxygen demand (COD) and color, increase in biodegradability, removal of humic acids from leachate, combined processes, and the pre/post-treatment options are highlighted. The scope of future studies is summarized to attain sustainable solutions for restrictions associated with these methods for effective leachate treatment.

• Geophysics and Geophysical Exploration
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• v.27 no.3
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• pp.159-170
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• 2024

The bioreactor method, in which leachate is reinjected into a landfill for rapid decomposition and stabilization of buried waste, is being applied and tested at many landfills because of its numerous advantages. To apply the bioreactor method to a landfill successfully, it is very important to understand the behavioral characteristics of the injected leachate. In this study, electrical resistivity monitoring was performed to estimate the behavior of a landfill leachate in Korea where the bioreactor method was applied. For the electrical resistivity monitoring, a baseline survey was conducted in August 2013 before the leachate was injected, and time-lapse monitoring surveys were conducted four times after injection. The electrical resistivity monitoring results revealed reductions in electrical resistivity in the landfill attributable to the injected leachate, and the change in its characteristics over time was confirmed. In addition, by newly defining the electrical resistivity change ratio and applying it in this study, the spatial distribution and behavior of the leachate over time were effectively identified. More research on optimization of data acquisition and integrated monitoring methods using various techniques should be conducted in the near future.

• Journal of the Korean GEO-environmental Society
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• v.13 no.1
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• pp.5-13
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• 2012

For the last decade the amount of waste has rapidly been increased in South Korea and many waste landfills have been built according to government guidelines specifying required systems such as landfill liner, leachate collecting facilities, final cover system, etc. This effort has led the recently constructed landfills to be under well managed sanitary condition. In a meanwhile closed waste-landfill sites in the past before the adoption of the government guidelines exits under unsanitary condition. In these cases untreated leachate flew out to the surroundings due to the absence of liner and leachate collecting facilities and caused groundwater and soils to be contaminated. Waste generated odor and gas also brought civil complaints. Because environmental influences bring serious problems nearby sites, it is required to have unsanitary waste-landfills to be appropriately treated and managed. A study to evaluate environmental influence and contamination level of surroundings nearby and on the unsanitary landfills is necessary before the establishment of "Management guide of closed landfill site." This paper presents an environmental evaluation for the closed site, Doil-dong landfill, according to "Closed landfill management regulation" by Ministry of Environment. "D" landfill, located in Pyeongtaek city, has possobility to contaminate surrounding surfacewater and groundwater by leakage of leachate. The in-situ stabilization carried out to build the DMW(deep soil mixing cutoff wall) wall and drainage systems.

• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.943-949
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• 1998

This study is concerned with the treatment of landfill leachate by carrier meditated emulsion. Using the batch operation, the optimum conditions for the removal of anionic and cationic materials were obtained. The landfill leachate from the plant was experimented under these conditions. The experimental variables were surfactant (Arlacel80) concentration and carrier(Aiquat336, DEHPA) concentration in membrane phase and counter ion concentration in internal phase. More than 80%(COD) of landfill leachate component could be removed within 12 minutes. The most crucial experimental variable for the removal efficiency was carrier concentration in membrane phase. In the other variables, the reaction time was more effected than the removal efficiency.

• Journal of environmental and Sanitary engineering
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• v.18 no.1
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• pp.23-29
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• 2003

The effect of ozone oxidation on bio-degradability of leachate was studied. Ozone oxidation process was used as pre-treatment process to enhance performance of biological process in treating landfill leachate. Optimum ozone injection rate and contact time in this experiment was $160{\;}mg{\;}O_/{\ell}{\cdot}hr$ and 45 minutes, respectively. Bio-degradability was enhanced 5.08% by ozone oxidation. The ratio of ozone demand/DOC concentration was $0.049~0.091{\;}mg{\;}O_3/mg{\;}DOC$. The increase of bio-degradability depending on ozone injection rate(D) and contact time(T) can be expressed as follows ; The rate of bio-degradation of DOC was increased proportionally with the increase of ozone injection rate and contact time irrespective of landfill site age. The increase of bio-degradability by ozone addition was not satisfactory. It is hard to expect significant increase in bio-degradability by ozone treatment only. Thus, it is evaluated that ozone oxidation can not increase biodegradability significantly in concentrated wastewater composed of complex organic compound such as leachate.

• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.1-6
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• 2005

The effect of ozone oxidation on biodegradability of leachate was studied. Ozone oxidation process was used as pre-treatment process to enhance performance of biological process in treating landfill leachate. Optimum ozone dosing rate and contact time in this experiment was $160mg\;O_3/L$ hr and 45 minutes, respectively. Biodegradability was enhanced 5.08% by ozone oxidation. The ratio of ozone demand/DOC concentration was $0.049{\sim}0.091mg\;O_3/mg$ DOC. The increase of biodegradability depending on ozone dosing rate(D) and contact time(T) can be expressed as follows ; ${\Delta}E=0.00479{\cdot}D^{0.773}{\cdot}T^{0.800}$ The biodegradation rate of DOC was increased proportionally with the increase of ozone dosing rate and contact time irrespective of landfill site age. The increase of biodegradability by ozone addition was not satisfactory. It is hard to expect significant increase in biodegradability by ozone treatment only. Thus, it is evaluated that ozone oxidation can not increase biodegradability significantly in concentrated wastewater composed of complex organic compound such as leachate.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.1
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• pp.127-133
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• 2001

It can be known that from leachate generated in the initial stage of landfill there are a lot of undecomposed orgainc materials, its sulfur component reduces to sulfide ion by sulfur reducing microorgarnisms as an anaerobic digestion proceeds, the sulfide ion makes the leachate discolor to black by forming metal sulfide sol, on condition that much more equivalent of sulfide ion than that of metal ion is present, and the metal sulfide sol can be generated to the precipitates by forming black-colored particulates. Therefore, we can confirm the important possibility for the economic and efficient treatment of leachate that it can be passivated, provided that much more equivalent of sulfide ion is present in the reaction of sulfide ion and metal ion.

• Journal of Korean Society on Water Environment
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• v.28 no.5
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• pp.657-662
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• 2012

This study was carried out to evaluate the removal rate of organic and inorganic matters from landfill leachate using pre-treatment process as coagulation and limonite adsorption, and membrane process as RO (reverse osmosis) and NF(nanofiltration). By adding limonite adsorption as pre-treatment process, about 40% of organic matters in leachate was removed through pre-treatment process and 74.7% of boron was removed after RO process without pH adjustment. The rejection rate of boron in RO process mainly depends on the pH and increased at pH value of 10. RO process was performed as two stage system adjusting pH condtion to 7 and 10 in second RO stage for boron removal. Most (>90%) of TOC, Cl- and inorganic matters as Ca was rejected in first RO stage, the residue was rejected in second RO and the rejection rate was above 97%. Considering economic efficiency of operation cost, NF substituted for the first RO and total removal rate of TOC was above 90%. Through RO system toxicity to Daphnia in leachate was removed completely.