• Journal of the Korean Society of Groundwater Environment
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• v.6 no.3
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• pp.152-157
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• 1999

Oil leaked from underwound storage tanks and leachate from sanitary landfills have been known as contaminant sources of the high-quality groundwater resources. The mobility of contaminants in the aquifer largely depends on the groundwater flow and the determination of associated hydraulic parameters is essential for a proper remediation of contaminated grnundwater. This study aimed at determining an optimum set of hydraulic parameters for an unconfined sandy aquifer of a laboratory scale through comparison of various methods. Results showed that the specific yield obtained from gravity drainage experiment was an average of 0.20 with minor variations in aquifer depths. and the permeabilities obtained from Dupuit approximation and slug test gave similar values of 5.33 cm/min and 5.85 cm/min but the constant head method gave 0.17 cm/min, which is much ion than the other methods. This experimental evidence reveals that the permeability of the unconfined sandy aquifer could be accurately determined by Dupuit assumption or slug tut rather than by constant head method conducted for a disturbed separate soil column.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.800-808
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• 2005

The compounding resin for biodegradable wrap was developed, and its manufacturing process and physical properties were studied. For these purposes, following factors were optimized: the types and amounts of raw resin material, anti-oxidants, and lubricants used. In this work, the stable compounding resin used to make biodegradable wrap was based on poly(butylene adipate-co-butylenesuccinate) (PBAS) and poly(butyleneadipate-co-butylene succinate-co-butyleneterephthalate) (PBAST). The improved properties of resin with an additive were investigated by melting flow index (MFI). From these results, the physical properties of compounding resin, based on PBAST, were more than those of PBAS. For PBAS, the Irganox 1010, 1076 and Irgafos TNPP as the first and second anti-oxidants, respectively, were good. For PBAST, the good first and second anti-oxidants, respectively, were Irganox 1076 and Mark PEP 36. The good lubricants for feeding PBAS and PBAST were glycerol monostearate and palmityl alcohol, respectively. The stability and tensile strength experiment of wrap were also investigated by the elution of heavy metals and universal testing machine (UTM), respectively. The decomposition ratio of developed wrap was increased proportional to the reclaiming time. The degradation ratio of compounding resin sample was about 60% after 40 days.

• Geophysics and Geophysical Exploration
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• v.8 no.1
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• pp.26-33
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• 2005

Inversion of multi-mode surface-wave phase velocity for shallow engineering site investigation has received much attention in recent years. A sensitivity analysis and inversion of both synthetic and field data demonstrates the greater effectiveness of this method over employing the fundamental mode alone. Perturbation of thickness and shear-wave velocity parameters in multi-modal Rayleigh wave phase velocities revealed that the sensitivities of higher modes: (a) concentrate in different frequency bands, and (b) are greater than the fundamental mode for deeper parameters. These observations suggest that multi-mode phase velocity inversion can provide better parameter discrimination and imaging of deep structure, especially with a velocity reversal, than can inversion of fundamental mode data alone. An inversion of the theoretical phase velocities in a model with a low velocity layer at 20 m depth can only image the soft layer when the first higher mode is incorporated. This is especially important when the lowest measurable frequency is only 6 Hz. Field tests were conducted at sites surveyed by borehole and PS logging. At the first site, an array microtremor survey, often used for deep geological surveying in Japan, was used to survey the soil down to 35 m depth. At the second site, linear multichannel spreads with a sledgehammer source were recorded, for an investigation down to 12 m depth. The f-k power spectrum method was applied for dispersion analysis, and velocities up to the second higher mode were observed in each test. The multi-mode inversion results agree well with PS logs, but models estimated from the fundamental mode alone show f large underestimation of the depth to shallow soft layers below artificial fill.

• Journal of the Korean GEO-environmental Society
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• v.20 no.5
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• pp.23-29
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• 2019

In general, pipe laying works are performed by constructing underground facilities such as pipes and then refilling the rest of the area with sand or soil. However, there are many problems in the compaction process such as difficulties in tampering around the underground facility and low compaction efficiency. Such problems cause deformation and damage to the underground pipes during refilling work and ultimately cause road sinks. Construction methods using CLSM are one of the typical methods to solve these issues, and recently, studies on CLSM using coal ash, which has similar engineering properties as sand, have been actively performed to protect environment and recycle resources. While many studies have been conducted to recycle fly ash in many ways, the demand for recycling bottom ash is increasing as most of the bottom ash is not recycled and reclaimed at ash disposal sites. Therefore, in order to find bottom ash applications using eco-friendly soil binders that are environmentally beneficial and conform with CLSM standards, this study investigated flow characteristics and strength change characteristics of eco-friendly soil binders, weathered granite soil, a typical site-generated soil, bottom ash, and fly ash mixed soil and evaluated the soil pollution to present CLSM application methods using bottom ash.

• Analytical Science and Technology
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• v.19 no.1
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• pp.86-95
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• 2006

This study was carried out to estimate leaching characteristics of incineration residues from municipal solid waste incinerators, and determine organic compounds in raw ash, leaching water and leaching residue. A total of 44 organic compounds, which were analyzed by GC/MSD and identified by wiley library search, were contained in bottom ashes. A total of 17 organic compounds were contained in fly ashes. Bottom ash and fly ash were found to contain a wide range of organic compounds such as aliphatic compounds and aromatic compounds. Organic compounds such as Ethenylbenzene, Benzaldehyde, 1-Phenyl-Ethanone and 1,4-Benzenedicarboxylic acid dimethyl ester were detected in raw ash, leaching water and residues (from bottom ash). Organic compounds such as Naphthalene, Dodecane, 1,2,3,5-Tetrachlorobenzene, Tetradecane, Hexadecane and Pentachlorobenzene were detected in raw ash, leaching water and residues (from fly ash). Through the leaching characteristics of incineration residue, it was represented that the open dumping of incineration residue can contaminate the soil and undergroundwater. In order to prevent environmental contamination that derived from extremely toxic substances in the incineration residues, it is particularly important that the incineration residues should be treated before disposal the incineration residues. Further study and proper management about leaching characteristics of organic compounds might be required.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.3
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• pp.333-344
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• 2022

The quarrying and utilization of natural building stones such as granite and marble are rapidly emerging in developing countries. A huge amount of wastes is being generated during the processing, cutting and sizing of these stones to make them useable. These wastes are disposed of in the open environment and the toxic nature of these wastes negatively affects the environment and human health. The growth trend in the world stone industry was confirmed in output for 2019, increasing more than one percent and reaching a new peak of some 155 million tons, excluding quarry discards. Per-capita stone use rose to 268 square meters per thousand persons (m²/1,000 inh), from 266 the previous year and 177 in 2001. However, we have to take into consideration that the world's gross quarrying production was about 316 million tons (100%) in 2019; about 53% of that amount, however, is regarded as quarrying waste. With regards to the stone processing stage, we have noticed that the world production has reached 91.15 million tons (29%), and consequently this means that 63.35 million tons of stone-processing scraps is produced. Therefore, we can say that, on a global level, if the quantity of material extracted in the quarry is 100%, the total percentage of waste is about 71%. This raises a substantial problem from the environmental, economical and social point of view. There are essentially three ways of dealing with inorganic waste, namely, reuse, recycling, or disposal in landfills. Reuse and recycling are the preferred waste management methods that consider environmental sustainability and the opportunity to generate important economic returns. Although there are many possible applications for stone waste, they can be summarized into three main general applications, namely, fillers for binders, ceramic formulations, and environmental applications. The use of residual sludge for substrate production seems to be highly promising: the substrate can be used for quarry rehabilitation and in the rehabilitation of industrial sites. This new product (artificial soil) could be included in the list of the materials to use in addition to topsoil for civil works, railway embankments roundabouts and stone sludge wastes could be used for the neutralization of acidic soil to increase the yield. Stone waste is also possible to find several examples of studies for the recovery of mineral residues, including the extraction of metallic elements, and mineral components, the production of construction raw materials, power generation, building materials, and gas and water treatment.