• Journal of the Korean Geosynthetics Society
• /
• v.8 no.3
• /
• pp.35-44
• /
• 2009

The purpose of this study was to prevent spreading of contaminants from movement of underground water by creating a barrier using artificial freezing method on a soil contaminated by oils and various NAPLs. Specimens with 80% and 90% degrees of saturation were prepared to form freezing barrier using artificial freezing method. With increasing freezing time of freezing barrier, barrier was formed faster in the specimen with 90% degree of saturation by about an hour compared to the specimen with 80% degree of saturation. In addition, thinnest thickness of frozen barrier in both specimens was 50mm after 12 hours of freezing time, showing expansion of freezing area with time. The results of this study can be applied to barrier in waste reclamation sites and contaminated regions or to flow control of contaminants.

• Journal of the Korean Institute of Gas
• /
• v.17 no.6
• /
• pp.27-32
• /
• 2013

Renewable gas fuels such as biogas and landfill gas are obtained from the biodegradable organic wastes so that they inherently have carbon-neutral nature which can respond global warming. Therefore, attentions are paid to use this renewable gases as a main fuel for internal combustion engines. However, the composition of the fuel varies by its origin or conversion process, it is necessary to make stable combustion and accomplish high efficiency when used in power generating spark ignition (SI) engines. In this study, efforts have been made to investigate the effect of the composition of renewable gas fuel on the engine performance and exhaust emissions. In addition, a new spark plug with a long electrode was tested and compared with a base spark plug as a way to improve engine efficiency and reduce harmful emissions.

• Journal of the Korea Institute of Building Construction
• /
• v.14 no.1
• /
• pp.94-101
• /
• 2014

Approximately 240,000 tons of waste shells are produced annually in the south and west coast of South Korea. Some of these waste shells (oyster, cockle) are recycled as seeding collector and fertilizer, but most are dumped illegally near the coast. One of the alternative solutions that can economically utilize a large amount of these waste shells is to apply them to the production of construction materials. In this research, the basic physical properties of waste shells such as oyster, cockle, clam, manila clam were investigated, and were used to prepare cement mortar with a 25% replacement ratio of sand. According to the results, the 28 day compressive strength of cement mortar with cockle and manila clam shells was similar to that of plain cement mortar. The compressive strength decreased by about 18% when clam was used. However, the cement mortar with oyster shell showed about a 35% reduction in 28-day compressive strength, and two times the absorption capacity of plain cement mortar. The reduction in compressive strength and the increase in absorption capacity were mostly associated with the porous nature of the oyster shell.

• Journal of the Korean GEO-environmental Society
• /
• v.2 no.3
• /
• pp.81-88
• /
• 2001

The behavior of porous medium is modeled by linear thermoporoelastic behavior, linear poroviscoelastic behavior, poroplastic behavior, and poroviscoplastic behavior, etc. The behavior has, in general, a complicated aspect which makes a mechanical description of the problem with time. Constitutive modeling for deformation behavior of porous medium with coupling effects is needed since there is interaction between the constituents in pores with a relative velocity to each other. In this work, it is explained 3-dimensional behavior depending on degree of saturation for porous medium composed of homogeneous, isotropic materials. It is obtained the governing equations based on continuum porous mechanics. In addition, it is developed constitutive model which can be understood of behavior for porous medium which can be understood, analysed behavior of porous medium. It can be accomplished exact analysis and prediction of behavior in porous medium. The behavior for porous medium is analysed exactly, and the prediction of deformation behavior is accomplished. Consequently, it will be basis to analyze 3-dimensional behavior in municipal solid waste landfill, and the practical using of porous medium ground which are composed of nonhomogeneous, anisotropic materials can be done widely.

• Journal of the Korean GEO-environmental Society
• /
• v.5 no.4
• /
• pp.57-63
• /
• 2004

In general steel sheet piles are used in the containment system, which are vertical barrier systems for waste disposal and landfill purposes, and roads in excavation for temporary structure. This paper presents case study of the use of an interlocking sheet pile for water and containment. Cut-off Z-type sheet pile joints are investigated to determine their permeability from the field test. Four different joint sealing materials are used in field test. The results showed joint permeability is significant time-dependent and joint-dependent. These are explored and conclusions on permeability characteristics of different sealants are noted. A case study gives a design example as well as suggestion on permeability and water tightness can be implemented in using the sheet pile barrier in civil and environment works. From the test results, the effective sealing programs of sheet pile interlocks are suggested.

• Journal of the Korean GEO-environmental Society
• /
• v.4 no.4
• /
• pp.25-34
• /
• 2003

This paper is focused on an experimental study in order to investigate the utilization of sewage sludge ash as the cover and liner materials for the waste disposal landfill or as construction materials. A series of tests were performed to evaluate the basic properties, compaction, compressive strength, consolidation, permeability, and CBR of sewage ash. Specially, clay bricks were made as increasing replacement ratio of sewage ash (such as 5, 10, 15, 20, 25, 30%). And tests were fulfilled for its quality. Bentonite and lime were used as the additives to improve permeability properties of sewage sludge ash. As a result of tests, it was shown that the permeability coefficient decreases as increasing bentonite content and the percentage of bentonite was roughly needed 20% to keep the permeability coefficient below $1{\times}10^{-7}cm/sec$. The results of unconfined compression tests show that sewage ash meets the criteria of the unconfined compression strength for cover material. It was shown that the compressive strength decreases as increasing the replacement ratio of sewage sludge ash and the maximum replacement ratio of sewage sludge ash to satisfy the quality standards of the third degree bricks was about 15%.

• Journal of Environmental Health Sciences
• /
• v.27 no.1
• /
• pp.56-62
• /
• 2001

The investigation was carried out to analyze the generation and the composition of landfill gas generated from inserted pipe wells into the underground by boring operation and also study the undecomposed waste characteristics by open-cut test at S. waste landfill site in Pusan city. Pilot test was conducted for stabilization. The experimental results from this study were summerized as follows. ; Since COD matter was easuer decomposed than COD matter for continuously biological stabilization in underground, it seemed that BOD and CO $D_{Mn}$ were in the range of 854~4,813mg/$\ell$ and 1,156~6,977mg/$\ell$ and their ratio were generally as high as 0.55~0.74. As C $H_4$ compositions of generated gas were measured in the range of 37.36~60.1%, we could know that C $H_4$ gas was actively generated. Organic matters by open-cut test averaged 13.4~16.6% at each landfill layer, and considering rate of combustible compositions(36.2~66.5%) for landfilling wastes, they have been actively decomposed. The measured and theoretical values of generated gas in waste landfill site were almost similar to C $H_4$ 50.0% and 53.4%, $CO_2$ 39.63% and 45.24%, and after 0.5$^{\circ}C$ with heavy depth and long landfill period. From the results of pilot test for stabilization, after 180 days organic matters were actively decomposed beyond 2.2 times in facultative aerobic lystimeter(B) to exsiting anaerobic lysimeter(A). Therefore, it seemed that landfill site was of benefical to the conversion of facultative aerobic for stabilization.

• Journal of environmental and Sanitary engineering
• /
• v.11 no.1
• /
• pp.45-55
• /
• 1996

An experimental research was conducted in order to study the combined treatment o of municipal landfill leachate and municipal sewage. The landfill leachate was that of Nanjido landfill site, and the municipal sewage was that of Chungnang municipal sewage treatment plant in Seoul. Several sets of bench~scale sequencing batch reactor(SBR) were used as e experimental apparatus. Specially investigated items in this experiment were the removal efficiency of substrate and the influence of treatment time. The experiment lasted for about 2 years. The result are as follows ; 1. The characteristics of leachate were pH 7.5~8.2, BOD 80~336mg/L, COD 908~1,460mg/L, NH3-N 1,409~2,330mg/L, T~P 2.7~7.lmg/L, Cl~3,540~4,085mg/L, a and heavy metals are a very small amount. And the characteristics of sewage were pH 6.9~7.3, BOD 78.4~129.3mg/L, COD 121.2~305.0mg/L, T~N 14.9~36.4mg/L, T-P 2.3~8.9mg/L. 2. The treatability of leachate alone was not treat well. So for the good treatment of leachate, it was necessary to deal with the pretreatment before bi이ogical treatment and a combined treatment of municipal sewage. 3. The various contents of the leachate were 5%, 10%, 30%, and 50%, and the removal efficiency of COD was 86.0%, 82.8%, 60.6%, and 31.7%. The maximum content of the leachate which could be sucessfully treated by SBR in the combined treatment was 10% of that of sewage. And the removal efficiency of COD increased n notably, as its treatment time increased. 4. The various contents of the electrolytic treated leachate were 5%, 10%, 30%, and 50%, and the removal efficiency of COD was 89.9%, 86.1%, 79.2%, and 69.8%. The maximum content of the leachate which could be sucessfully treated by SBR in the combined treatment was 30 % of that of sewage. And the removal efficiency of C COD increased notably, as its treatment time increased.

• Journal of the Korean Geotechnical Society
• /
• v.18 no.1
• /
• pp.79-89
• /
• 2002

Various geosynthetics used as liners or protection layers are installed in the solid waste landfills. The interface shear strength between geosynthetics installed at the slope of the landfill is a very important variable for the safe design of the bottom and cover systems in the solid waste landfills. The interface shear strength between Geomembrane and Geotexile is estimated by a large direct shear test in this study, The effects of normal stress, water existing between geosynthetics and surface condition of Geomembrae, i.e. smooth or textured, were investigated. The test results show that the effect varied depending on the level of normal stress and the type of geosynthetic combinations. The shear strength was evaluated by the Mohr-Coulomb failure criterion in this research. The shear strength parameters obtained from tests considering the site specific conditions such as normal stress, dry or wet, and surface condition of geosynthetic should be applied to the design of geosynthetics installed at the slope of the landfill to construct a safe solid waste landfill.

• Journal of the Korean Geotechnical Society
• /
• v.18 no.1
• /
• pp.133-140
• /
• 2002

Phosphogypsum is a by-product from the phosphoric acid process for manufacturing fertilizers. It consists mainly of $(CaSO_4.2H_2O)$ and contains some impurities such as$(P_2O_5)$, 불소$(F_-)$, and organic substances. The annual world production of this material is up to 150 million tons and is up to 1.57 million tons in Korea. Therefore studies describe application of phosphogypsum to daily and middle cover materials in landfill. For this Purpose, experiments were performed to evaluate the engineering properties of the material by sieve analysis, specific gravity, consistency of soil, compaction, CBR, permeability, mi environmental characteristics of leaching test, reactor test. The results of this study are as follows : The mixing and layer conditions of CBR value are 6.2~6.3%, coefficient of permeability is $\alpha$$\times10_{-5}~10_{-6}cm/sec$. And leaching test results are far below than those of regulatory requirement of Waste Management Act, Soil Environment Preservation Act in Korea and RCRA in USA. Therefore phosphogypsum can be used as daily and intermediate cover materials in landfill.