• Korean Journal of Environmental Agriculture
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• v.21 no.1
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• pp.45-49
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• 2002

To estimate annual pollutant loading rate of n-hexane extractable material (HEM) to soil 84 sewage sludge samples were analyzed. The average content of HEM was 27.7$\pm$26.5 g/kg, and ranged from 1.05 to maximum 194 g/kg. According to the number of population of the city the areas were classified as five regions, i.e. big, large, middle, small, and rural area in which the waste water treated plants were grown. The contents of HEM were 22.7$\pm$16.7, 33.3$\pm$25.8, 22.0$\pm$8.7, 31.0$\pm$38.8, 27.7$\pm$25.1 g/kg, in big, large, middle, small, and rural area, respectively. The applicated areas with sewage sludge to land also were divided as 4 sites by US EPA criteria such as agricultural, forest, public contact sites, and reclamation site. The quantitation of annual pollutant loading rate was estimated using a function (99 percentile concentration = $\bar{X}$ + 3$\sigma$) when the application amounts were in dosages of 7,000, 26,000, 18,000, 74,000 kg/ha in 5 regions, respectively. The annual pollutant loading rate of HEM to soil by sewage sludge application was maximum 1,032, 3,832, 2,653, and 10,908 kg/ha in agricultural, forest, public contact sites, and reclamation site, respectively.

• Journal of Soil and Groundwater Environment
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• v.16 no.2
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• pp.52-60
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• 2011

Although facilities for the passive treatment of AMD (Acid Mine Drainage) are currently operating in Korea, their removal efficiency for heavy metals is relatively low in average (only 80%). Passive treatment system is composed of oxidation tank, SAPS (Successive Alkalinity Producing System), and wetland. In the treatment system adopted in korea, SAPS (Successive Alkalinity Producing System) plays a major role to remove about 65% of heavy metals through a precipitation. However, the efficiency of SAPS is limited due to the use of mushroom compost (MC) as a organic material and of limestone as a neutralizer. Therefore, this research was performed to search for alternative organic materials through the field test. We tested two types of mixed organic materials: 1) cow manure and spent oak (herein, CO) and 2) cow manure and sawdust (herein, CS). For comparison mushroom compost (herein, MC) was also tested. The result showed that the average Fe removal efficiency was 91.38% with CO, 85.19% with CS, and 91.58% with MC. Thus, CO can be effectively used as an alternative of MC in the SAPS system for heavy metals removal.

• Tunnel and Underground Space
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• v.27 no.6
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• pp.357-365
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• 2017

The mine subsidence prevention technology has been promoted based on the field test for design, construction, automation measurement and monitoring optimized for investigation, design and mine-filling efficiency customized in Korean mining environment. Based on the R&D roadmap ('07~'16) of the 1st and 2nd stage, mine reclamation technology development has been focused on developing method of evaluating subsidence stability, development of filling material and optimum filling technology, and development of measuring instrument. In the future, in order to systematic management for the subsidence risk areas, we intend to enhance technological capabilities and strengthen the technological infrastructure for business promotion in parallel with the discovery and introduction of new technology to prevent subsidence in the 4th Industrial Revolution era.

• Journal of Korean Society of Forest Science
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• v.98 no.4
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• pp.496-503
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• 2009

Reclamation area is characterized by high soil salinity and high ground water table that are not favorable environment for tree growth. However, the increasing demand to convert the reclamation area from rice cultivation fields to industrial or residential complex, or parks accompanies the idea of introduction of trees in the area. This study aimed to suggest better performed tree species for the tree planting in the Seosan reclamation area, Chungchungnam-do. Seedlings of 8 tree species (Pinus densiflora, Pinus thunbergii, Metasequoia glyptostroboides, Chionanthus retusus, Cornus kousa, Prunus sargentii, Quercus acutissima, and Zelkova serrata) were planted in 4 types of 10 m ${\times}$ 10 m experimental plots. The survival rate and the height growth of seedlings were measured from April 2006 to November 2008 on an annual basis. The experimental plots were constructed using 2 different soil material (dredged sand and dredged sand + forest soil), and 2 soil covering depth (1.5 m and 2.0 m). The tree species showed different survival rates for 3 years since planting (F = 9.632, P < 0.001). C. kousa, Q. acutissima, and P. sargentii showed high mortality rate while P. thunbergii, M. glyptostroboides and Z. serrata showed lower mortality rates. The seedling height growth for 3 years was also significantly different among species (F=4.749, P=0.002). Most of seedlings showed lower height growth in the second year, and the growth began to recover in the third year after transplanting. The survival rate and the growth of the seedlings were better in higher soil covering depth and forest soil material plots regardless of species. The combination of rank orders in survival rate and relative height growth indicates that P. thunbergii, M. glyptostroboides and Z. serrata would perform better than other species used in the experiment, while C. retusus, C. kousa and P. sargenti may not adapt well to this area.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.335-340
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• 2002

By the recently, Environmental pollution is serious by the highly economic growth and expansion of lively country basic industry. Especially, in case of industrial waste and life waste leaped into a pollution source. Also, research for processing of waste and recycling countermeasure is a pressing question on national dimension because it is prohibited an ocean disposal and reclamation. In this study, it looked for fracture characteristic value of recycling a coal ash to decrease environmental pollution by picky and exhaustion of natural resources and to reduce self-weight to prepare for a tall building and earthquake. So a coal ash examined to be possible to do as construction material. It achieved compressive strength test and three points bending test with initial notch depth rate and age for variables to show a basic research data. From the basis of the three points bending test, the fracture parameters - notch sensitivity, fracture energy, initial compliance were experimentally proposed. From the results of the compressive strength test, the elastic modulus was experimentally proposed. Also on the basis of the three points bending test, the fracture parameters - notch sensitivity, fracture energy, initial compliance were experimentally proposed. The results that the strength and fracture energy value are lower than concrete or mortar is described in this paper. Also, it shows that the deflection at fracture decreases as the age increases and the notch sensitivity decrease. However, it is judged to be available to construction material if research is continuously gone forward.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.113-118
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• 2007

Now a performance process of Demolition works is 'Before-Removal & After-Classification' method in Korea. This method is short of demolition time, but construction wastes contained substances lower recycling rate of construction, raise expenses of reclamation & treatment. Then the government has decided upon a positive 'Before-Classification & After-Removal' method, and substantially raise a recycling rate of construction wastes. Therefore, this study makes an investigation into state of internal and external demolition field through evaluating technological level, we make a proposal of dismantling method from there. Also, we put dismantling to the test in an apartment by proposed work process. As the result, it made a term of works increased for removing interior material. To solve this problem, we need to develop tools and methods of construction that can remove efficiently. From now on, we continuously need to study a breakdown system of dismantling, analysis of dismantling process and general system by inspecting entire demolition process. And we have to study details for making a specific thesis of method of removing interior material which was based on developing a suitable partial demolition machine and dismantling works.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.665-672
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• 2002

In order to expand agricultural lands in the western and southern coasts of Korean Peninsula, coarse soils excavated from hillsides have been used as fill materials for reclamation. In order to tackle with the problems and to confirm availability, research on soil improvement involve mixing cement to the fine wet soils. Required undrained shear strength(c$\sub$u/) for fill material was analyzed to be 0.34∼1.2kg/$\textrm{cm}^2$. It has been known that when cement is added to high water content marine clay, its unconfined compression strength increased to 2kg/$\textrm{cm}^2$. Consolidation results show that pre-consolidation pressure increased to 1.8kg/$\textrm{cm}^2$ and 3.4kg/$\textrm{cm}^2$ with the addition of 3% and 5% of cement respectively. This result shows that low-height embankments could be constructed without significant compression. Since the effectiveness of improvement may be different site by site, the mix design for each site is necessary in order to optimize it. The process is first to determine aimed shear strength and then optimum mix ratio of cement after carrying out a series of tests.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.44 no.1
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• pp.75-80
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• 2008

A scrapped fiber-reinforced plastic(FRP) fishing vessel causes many environmental problems, because technology development for recycling FRP vessel has not been adequately addressed. FRP is a main material for constructing a small coastal fishing vessel that is an object of reduction policy. Therefore, the FRP wastes derived a scrapped fishing vessel are increasing. In this study, I investigated an effective disposal process for FRP through the analysis of the actual conditions of scrapped FRP fishing vessel. The treatment processes of scrapped FRP fishing vessel are carried out with oil-removing, dismantling, intermediated processing(crushing), and then reclaiming follows burning in the final processing in Korea. However, in Japan, several recycling methods have been developed, for example, the incineration including thermal recovery, the use of cement-reclamation, and the use of asphalt concrete aggregate, because the method of reclaiming after incinerating which is generally used in Korea produces a toxic by-product such as dioxin.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.219-222
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• 2003

Bech scale tests were performed to evaluate the adaptability of industrial wastes, especially bottom ash, salg and phosphogypsum among others, for constructing the surface layer of a landfill or reclamation, which function is a vegetation base layer. In the test, columes test were used to check the extraction characteristics of wastes and small PVC soil-box that equipped the drainage device was used to model a performance of layers and to monitor the growth of plants at the composite layer of those. Tests have been continued during one and half year and It has been verified that bottom ash and phosphogypsum look like as a valuable material to safely reuse as the vegetation base layer even though some unconfined factors are remain.

• Journal of Industrial Technology
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• v.28 no.B
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• pp.65-69
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• 2008

The tailings piled in abandoned mines are well-known potential sources of soil contamination. Hydrated limes were applied as cementing materials to solidify heavy metal contaminated tailings for the purpose of reducing their toxicity and migration rates. The optimum mixing ratio of tailings, hydrated lime, and water was determined through a preliminary test. The mixtures of mine tailings and hydrated lime solidified through pozzolanic reaction were tested for their durability against repeated freezing and thawing processes. After repeated freezing and thawing, the uniaxial compressive strengths of all the solidified mixture specimens decreased in comparison with those before test but still higher than $3.5kgf/cm^2$, the standard recommended for land reclamation solids by EPA(Environmental Protection Agency), which suggested that hydrated lime be a potential material to treat the abandoned mine tailings for the environmental purpose.