• Analytical Science and Technology
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• v.27 no.5
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• pp.254-260
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• 2014

In this study, heavy metals, PCDD/PCDFs, PAHs in wastes generated from thermal processes were analyzed. Waste from lead thermal metalurgy (EWC 10 04) inorganic metal substances in the regulation were detected in the highest concentrations of Pb. EWC 10 04 seems to be a result of the dust. Waste from zinc thermal metalurgy (EWC 10 05) inorganic metal substances in the regulation were detected in high concentration of Zn. EWC 10 05 seems to be a result of the dust. Waste from copper thermal metalurgy (EWC 10 06) Cu in the 651,77 mg/kg to 651 times higher than regulation standard appeared in the copper thermal metallurgy process seems to be a result of dust. The concentrations of PCDD/PCDFs ranged from 0.0005~11.748 ng-TEQ/g in dust, 0.0027 ng-TEQ/g in fly ash. PCDD/PCDFs content was not detected in excessive value in regulation standard. PAHs concentration was in the range of ND~118.9 mg/kg in Naphthalene, ND~9.6 mg/kg in Phenanthrene, ND~48.4 mg/kg in Benzo[b]fluoranthene, ND~62.6 mg/kg in Benzo[a]pyrene, ND~10.7 mg/kg in Fluoranthene, ND~11.5 mg/kg in Benzo[a]anthracene.

• Journal of Environmental Impact Assessment
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• v.28 no.3
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• pp.312-331
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• 2019

An offshore waste disposal facility refers to a landfill site for final landfilling of stabilized inorganic solid waste such as land and marine waste incineration materials, and the aim of such a facility is to solve the problem of insufficient waste disposal space on land and create and develop environmentally friendly marine spaces. The purpose of this study is to prepare guidelines for the construction of offshore waste disposal facilities, which reflect the need and importance of paying sufficient heed to environmental considerations from the initial stage of the project, in order to investigate, predict, and assess how such guidelines will affect the marine environment in relation to the construction of offshore waste disposal facilities, with the goal of minimizing the impact on and damage to the environment. For the purpose of this research, guidelines focusing on the construction of offshore waste disposal facilities were derived through an analysis of domestic cases and similar foreign cases and an assessment of their level of compliance with existing EIA guidelines through the operation of a discussion forum. In order to review the EIA report on similar cases in Korea, 17 EIA documents (2005~2016) for dredged soil dumping areas and ash ponds of thermal power plants were analyzed to investigate the status of marine organisms, marine physics, marine water quality, and marine sediment and to understand what types of problems can occur and what improvement measures can be taken. The purpose of these guidelines were to minimize damage to the marine environment by promoting EIA protocols in accordance with scientific and systematic procedures, to reduce the consultation period related to projects, to resolve social conflicts, and to reduce economic costs.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.528-535
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• 2000

Solid waste incinerator is expected to become widely used in Korea. The incineration of solid waste produces large quantities of bottom and fly ash, which has been disposed of primary by landfilling. However, as landfills become undesirable other disposal method are being sought. In this study, an experimental research is conducted to determine the geotechnical properties of municipal solid waste incinerator fly ash(MSWIF) in order to evaluate the feasibility of using the material for geotechnical applications. Basic pysicochemical characteristics, moisture-density relationship, strength, permeability, and leaching characteristics are examined. The results of MSWIF are compared to other MSWIF and coal fly ash which are used as construction material. In addition, the effectiveness of cement stabilization is investigated using various mix ratios. The result of stabilized mixes are compared to the unstabilized material. Cement stabilization is found to be very effective in reducing permeability, increasing strength, and immobilizing heavy metals. This results indicate that MSWIF with cement stabilization may be used effectively for geotechnical application.

• Applied Chemistry for Engineering
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• v.21 no.2
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• pp.217-223
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• 2010

In general, fiber-reinforced plastics (FRP) wastes are simply buried or burned. Landfill brings about a permanent contamination of soil due to the inability of FRP to decompose and incineration causes an issue of generating toxic gases and dusts. There have been several ways to treat the FRP wastes such as landfill, incineration, chemical recycling, material recycling and the utilization of energy from combustion. Most methods excluding material recycling are known to have critical limitations in economic, technical and environmental manners. However it is known that material recycling is most desirable among the methods handling FRP wastes. In this study, to investigate the purpose of feasibility of material recycling, various bulk molding compound (BMC) specimens were prepared with the various contents of unsaturated polyester resin binder (25, 30, 35 wt%) and the various replacement ratios of FRP wastes powder (0, 25, 50, 75, 100 wt%) substituted for filler. To evaluate the physical properties BMC specimens, various tests such as tensile strength, flexural strength, impact strength, hot water resistance and SEM imaging were conducted. As a results, mechanical strengths decreased with an increase of replacement ratio of FRP waste powder and physical properties of BMC specimens were deteriorated in the hot water resistance. The fluidity of BMC with more than 50 wt% of the replacement ratio of FRP wastes powder decreased remarkably, causing a problem in the BMC composite.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.692-697
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• 2015

In this study, the reduction efficiencies of leachate heavy metal levels were investigated by adding $Al_2O_3$ and CaO to the bottom ash to observe their effects on the heavy metals leachate reduction efficiency. The ratio of $Al_2O_3$ and CaO contents were varied by 10~40% (W/W) alongside different curing time of 7 and 28 days. The reduction efficiencies of leachate heavy metal levels were estimated to be 69.3% for Cu and 52.1% for Pb during the curing time of 7 days. For the curing time of 28 days, the efficiencies changed to 85.2 and 100% for Cu and Pb, respectively. It was thus confirmed that the high reduction efficiency could be obtained as the curing time increased.

• Analytical Science and Technology
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• v.25 no.6
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• pp.421-428
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• 2012

In this study, PCDD/PCDFs, PAHs and PCBs in wastes from metal, plastic and wastewater treatment facilities were analyzed. The concentrations of PCDD/PCDFs ranged from 7.37~432.20 ng-TEQ/kg in fly ash, 0.51~855.01 ng-TEQ/kg in incinerated ash and 0.37~385.81 ng-TEQ/kg in dust. Dioxin content was lower, compared to data in foreign countries. PAHs concentration was in the range of 0.0075~2.9225 mg/kg for process sludge and 0.0035~1.6716 mg/kg for wastewater sludge, which satisfied all of the two standards (Nap, Ant, B(a)F:4/0.8, Phen, B(a)A:5/1, Flt:10/2.5, B(a)P:4.5/0.9) of the Marine Environment Management Act. PAHs concentration in process sludge and wastewater sludge were slightly lower than those abroad. According to the analysis of seven types of PCBs (in comparison with the first standard, 0.15 mg/kg), concentration was found in the range of 0.0~0.65 mg/kg, while PCB-52, PCB-101, PCB-138, PCB-153 and PCB-180 isomers were detected in excessive value in some machine oil and hydraulic fluid.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.3
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• pp.98-109
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• 2002

Each kinds of the leather process wastes which is occurred in the leather making process is almost more than 50% on the basis of the raw hide. The emitted process wastes are important oil and fats and protein resources because they are composed of animal oil and fats and fibrous protein. But most of them are incinerate or filled up simply as the industrial wastes without applying to recycling into the other use. Thus the problems of environmental pollution are becoming more critical and the processing cost of the leather process wastes (40,000~60,000 won) is a heavy burden on the production cost. Because the organic wastes such as fleshing scrap, pelt scrap are high fetid, its unlawful abandonment without being processed properly causes the occurrence of secondary pollution by an offensive odor and leakage of waste water. Thus we made the re-resource experiments in order to resolve this problems. The principal contents of this study are to process the collected leather waste scrape through separate the oil and fat ingredients with various propert by processing various chemicals and enzymes on the next effector. The re-resource application of separated oil and fat ingredients produced chemical for leather applicable to manufacturing process of leather through chemical transformation process(sulphation reaction, sulphitation reaction etc.) of oil and fats.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.1
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• pp.5-12
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• 2018

As many local governments have faced increasing conflicts on landfill use and the time of end use, it is difficult to provide an alternative landfill or conclude a consensus of lifespan extension for the existing landfill site. Therefore, the purpose of this study is to contribute improving of the landfill capacity by calculating the resource recovery potentials of landfilled waste previously and in the future by landfill mining. For this, rate of volume increase, weight ratio, and apparent density were adopted as major parameters and their values were calculated through previous cases. The rate of volume increase was calculated to 1.42 by averaging previous cases of three areas. The average weight ratio of soil matter was 45.6% by calculating for the three areas. For the combustible waste and incombustible waste, statistical data can be used. The apparent densities were divided by combustible waste, incombustible waste, and soil matter using an average of two areas value, i.e., $0.35ton/m^3$, $1.40ton/m^3$ and $1.58ton/m^3$. We analyzed the resource recovery potential of Cheongju landfill by using the estimated parameters. The additional landfill capacity was 45% of the existing landfill capacity by recovering landfilled waste by landfill mining. In addition, it is analyzed that the lifespan is extended to 20 years, if the combustible waste of new inputting waste is sorted and combusted for energy recovery and incineration ash, incombustible waste, and soil matter are only reclaimed into the existing Cheongju landfill. It is expected that the methodology and parameters of this study will be used as basic data when resource recovery potential is analyzed for another case study of landfill mining.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1116-1122
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• 2008

The existing technology which is for recycling aggregate using dried swage sludge have been limited for practical application, because the properties of aggregate are not regular and don't meet the recycling aggregate standard. In this research, an innovative slag-producing technology is developed by addition of oyster shell, waste cast-sand and iron-rust as inorganic waste additives. The mixed slag with the additives was evaluated at the various ratio of CaO/SiO$_2$, SiO$_2$/Al$_2$O$_3$ and Fe$_2$O$_3$/SiO$_2$. When the waste sludge was melted at 1,400$^{\circ}C$ during 20 minutes, the optimal ratio of CaO/SiO$_2$ for the slag added the oyster shell, SiO$_2$/Al$_2$O$_3$ for added the waste cast-sand and Fe$_2$O$_3$/SiO$_2$ for added the iron-rust were 1.00, 3.00 and 0.60, respectively. At the optimal condition, the bulk density of the slag was 2.24 g/cm$^3$, 2.45 g/cm$^3$ and 2.73 g/cm$^3$, And the 24 h water adsorption was 4.72%, 1.44% and 0.37%, respectively. Therefore it is proved that adding the waste additives to the process of the slag production contributed for elevation of recycling aggregate properties. And also it is expected that production cost can be reduced by decreased melting temperature.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.2
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• pp.15-29
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• 2020

The aims of this study is to improve physical properties of the sewage sludge and the process sludge generated in the leachate treatment by mixing the dry fuel, to develop the neutral solidifing agents that reduce oder, and to recycle the sewage and the process sludges as landfill cover materials. The mixing ratio (W/W) of sludges and dry fuel was appropriate at about 1:1, and the mixed materials were shown to be homogeneous at that ratio. We could know that when the sludges were mixed with dry fuel, moisture contents and viscosities are reduced, and air passages are formed between particles and particles. The various mixing tests and odor tests showed that the neutral solidifing agent was effective for the odor reduction. The main ingredient of the solidifing agent is the ash of sewage sludge, enabling it competitive in waste recycling and production costs. The landfill cover, using developed neutral solidification agent, improved physical properties to satisfy the quality standards and to increase the compressive strength. It also proved to reduce the value of complex oder and the usage of solidification agent to 1/3 (3,000 to 1,000) and to 1/8 (50% to 6%), respectively, from the comparative study with alkaline solidified landfill cover. Further research is under way to prove that this can be mixed with general soil to be used as a soil improvement agent for plant cultivation.