• Analytical Science and Technology
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• v.9 no.1
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• pp.98-106
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• 1996

The concentration of sulfur dioxide in Wonju City was predicted using TCM (Texas Climatological Model). We have studied the transportation and wet deposition of $SO_2$ using the TCM and the analysis of rainfalls. The results are as follows : At the Hak-Sung Dong site in Wonju city, the correlation coefficient between the measured and calculated concentrations were 0.904. Sulfur dioxide was washed out by wet deposition. The wet deposition ratio to total amount of emitted sulfur dioxide was higher in summer than in autumn and winter seasons due to heavy rainfall in summer. The correlation coefficient between the precipitation and wet deposition of sulfur dioxide was 0.68. The months with greater rainfall showed that the measured concentrations of sulfur dioxide were much lower than the predicted ones. Although the amount of precipitation in April was smaller than in summer, the wet deposition ratio in April was much higher than any other months, due to the sulfur dioxide that was adsorbed on particulate matter and moisture was transported during the period of yellow sand phenomena from China.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.492-498
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• 2021

This study examined how the emissions of pollutants affect the volume of traffic of freight vehicles in the transport sector. Multiple regression analysis was conducted considering several variables, including population by region, area of urban district, GDP, and the number of businesses by industry, e.g., agriculture, forestry, fishery, manufacturing, wholesale, and retail. These variables differ according to the characteristics of the freight vehicles (industry, by the ton). Therefore, it is essential to fully consider the volume of traffic of the specific freight vehicles by region before implementing relevant programs and policies, such as specific restrictions on the operation of vehicles. Some specific areas, in which logistic centers are located have heavy freight traffic, and these centers deserve extra consideration. Thus, in this study, different regional factors that affect the traffic of freight vehicles should be considered before determining the areas that will be subject to restrictions on the operation of these vehicles.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.4
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• pp.267-274
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• 2011

The environmental impacts of 95% remediation of a total petroleum hydrocarbon-contaminated soil were evaluated using life cycle assessment (LCA). LCA of two remediation systems, soil vapor extraction (SVE) and biopile, were conducted by using imput materials and energy listed in a remedial system standardization report. Life cycle impact assessment (LCIA) results showed that the environmental impacts of SVE were all higher than those of biopile. Prominent four environmental impacts, human toxicity via soil, aquatic ecotoxicity, human toxicity via surface water and human toxicity via air, were apparently found from the LCIA results of the both remedial systems. Human toxicity via soil was the prominent impact of SVE, while aquatic ecotoxicity was the prominent impact of biopile. This study also showed that the operation stage and the activated carbon replacement stage contributed 60% and 36% of the environmental impacts of SVE system, respectively. The major input affecting the environmental impact of SVE was electricity. The operation stage of biopile resulted in the highest contribution to the entire environmental impact. The key input affecting the environmental impact of biopile was also electricity. This study suggested that electricity reduction strategies would be tried in the contaminated-soil remediation sites for archieving less environmental impacts. Remediation of contaminated soil normally takes long time and thus requires a great deal of material and energy. More extensive life cycle researches on remedial systems are required to meet recent national challenges toward carbon dioxide reduction and green growth. Furthermore, systematic information on electricity use of remedial systems should be collected for the reliable assessment of environmental impacts and carbon dioxide emissions during soil remediation.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.5
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• pp.586-594
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• 2012

A future type ship power system requires both economic and eco-friendliness. That is, this should be reduced the discharge quantity of air pollutants and green-house gases as well as have high energy efficiency. Recently, gas turbines have been realized a lot of technical development in terms of efficiency and safety, and are widening the example of their adoption to a GT/ST hybrid system in a power plant as well as an aviation use. This paper reviewed the performance characteristics of a GT/ST hybrid system of several ten MW class, not large capacity, with a simulation in order to evaluate the possibility of a GT/ST hybrid system for ships. The reviewed GT/ST hybrid system has maximum 49 % efficiency, has the highest efficiency point for TIT, and has a 70~75 % and 25~30 % load ratio for a gas turbine and a steam turbine respectively.

• Clean Technology
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• v.25 no.4
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• pp.331-335
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• 2019

Interest in environmental pollution is increasing all over the world, and technology development to solve it is actively carried out. In areas where heat is used, especially, combustion is causing countless pollutants in the air environment. Combustion catalyst is a technology that reduces NOx and CO by lowering combustion temperature and enabling complete combustion. Traditional combustion catalysts are expensive and complex in the synthesis process using precious metal catalyst. In this study, hexaaluminate, a high-temperature combustion catalyst, was manufactured using urea, and the properties were investigated according to the synthesis time. The combustion performance and characteristics were evaluated using this catalyst. As the temperature increased, the changing methane conversion rate was shown in two patterns. The conversion rates for 1 hour, 9 hours, and 12 hours were similar, while the conversion rates for 3 hours and 6 hours showed similar patterns. Methane combustion performance increased rapidly as the synthesis time increased from 6 hours to 9 hours, whereas the temperature at T50 was approximately 745 ℃. The performance of the synthesized combustion catalyst for 9 hours was optimum as the NOx emission of this combustion catalyst was not present and the maximum emission of CO was 72 ppm.

• Journal of Animal Science and Technology
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• v.49 no.1
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• pp.137-146
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• 2007

This study was conducted to determine fertilizer nutrient and pollutant production of Holstein dairy cattle by estimating manure characteristics. The moisture content of feces was 83.9% and 95.1% for urine. The pH of feces and urine were in the ranges of 7.0～7.4 and 7.5～7.8, respectively. The average BOD5, COD, SS, T-N, T-P concentrations of the dairy feces were 18,294, 52,765, 102,889, 2,575, and 457mg/ℓ, respectively. Dairy urine showed lower levels of BOD5(5,455mg/ℓ), COD(8,089mg/ℓ), SS(593mg/ℓ), T-N(3,401mg/l), and T-P(13mg/ℓ) than feces. The total daily produced pollutant amounts of a dairy cow were 924.1g(Milking cow), 538.8g(Dry cow), 284.4g(Heifer) of BOD5, 2,336.5g (Milking cow), 1,651.8g(Dry cow), 734.1g(Heifer) of COD and 4,210.1g(Milking cow), 2,417.1g(Dry cow), 1,629.1g(Heifer) of SS and 194.8g(Milking cow), 96.4g(Dry cow), 58.3g(Heifer) of T-N and 24.0g(Milking cow), 10.2g(Dry cow), 6.1g(Heifer) of T-P. The calculated amount of pollutants produced by a 450kg dairy cow for one year were 181.3kg of BOD5, 492.5kg of COD, 899.9kg of SS, 36.0kg of T-N and 4.1kg of T-P. The total yearly estimated pollutant production from all head(497,261) of dairy cattle in Korea is 90,149 tons of BOD5, 244,890 tons of COD, 447,491 tons of SS, 17,898 tons of T-N and 2,008 tons of T-P. The fertilizer nutrient concentrations of dairy feces was 0.26% N, 0.1% P2O5 and 0.14% K2O. Urine was found to contain 0.34% N, 0.003% of P2O5 and 0.31% K2O. The total daily fertilizer nutrients produced by dairy cattle were 197.4g (Milking cow), 97.4g(Dry cow), and 57.9g(Heifer) of Nitrogen, 54.2g(Milking cow), 22.2g(Dry cow), and 14.2g(Heifer) of P2O5 and 110.8g(Milking cow), 80.4g (Dry cow), and 39.5g(Heifer) of K2O. The total yearly estimated fertilizer nutrient produced by a 450kg dairy animal is 36.2kg of N, 8.8kg of P2O5, 24.6kg of K2O. The estimated yearly fertilizer nutrient production from all dairy cattle in Korea is 18,000 tons of N, 4,397 tons of P2O5, 12,206 tons of K2O. Dairy manure contains useful trace minerals for crops, such as CaO and MgO, which are contained in similar levels to commercial compost being sold in the domestic market. Concentrations of harmful trace minerals, such as As, Cd, Hg, Pb, Cr, Cu, Ni, Zn, met the Korea compost standard regulations, with some of these minerals being in undetected amounts.

• Resources Recycling
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• v.11 no.6
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• pp.3-11
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• 2002

Recently, waste printed circuit board (PCB) has significantly increased in its amount due to the rapid development of electronic industries. Since several kinds of noxious materials and also valuable metals are contained in it, the waste PCB is in an urgent need of recycling for the dual purposes for the prevention of environmental pollution and recovery of valuable resources. Also, the catalyst which equipped in the exhaust pipes of automobiles to reduce emission of air pollutants contains precious met-als so that their recovery from the waste auto-catalysts is required. In this study, the recovery of valuable metals from waste PCB and auto-catalyst by arc furnace melting process has been investigated, which is known to be very stable and suitable f3r less production of pollutants due to its high operating temperature. The effect of the kind of flux on the recovery of precious metals was examined by using quicklime, converter slag, and copper slag as the flux. In addition, the influence of direct and alternating current and the applying direction of direct current has been investigated. It was observed that using converter or copper slag as a flux was more desirable for a higher efficiency in the precious metal recovery compared with quicklime. For the effect of current, application of direct current taking the bottom as a negative pole generally showed a better efficiency for the extraction of valuable metals from waste PCB, which was also observed for the case of waste auto-catalyst. The average recovery of precious metals from both wastes by arc furnace melting process was very high, which was up to in the range of 95～97%.

• Clean Technology
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• v.25 no.1
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• pp.19-32
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• 2019

As regional air pollution gets worse by the sulfur oxides emitted from various types of vessels passing through the many countries, the International Maritime Organization establishes the emission control areas and regulates sulfur dioxide in those areas. In order to satisfy these regional regulations, the fuel selection method and the exhaust gas post-treatment device are applied to the ships. Due to the economic reasons, the post-treatment method of exhaust gas for reducing the amount of sulfur oxides discharged is mainly preferred. The scrubber which is dominantly used in the ships are the spray type system where the sprayed liquid drops used for capturing the soluble sulfur dioxides in the exhaust gas. The performance of the spray type system depends on the size distribution of the sprayed droplets. In order to evaluate this performance, we designed counterflow type scrubber and cyclone scrubber and evaluated the desulfurization efficiency and the amount of droplet evaporation according to the size of each droplet by using computational fluid dynamics. The Eulerian-Eulerian analysis method was used because the scrubber had a gas-liquid two-phase flow inside the scrubber. When the diameter of the droplet was $100{\mu}m$, $300{\mu}m$, $500{\mu}m$ and $700{\mu}m$. As a result, both of scrubbers showed high desulfurization efficiency and low evaporation amount at $500{\mu}m$ and $700{\mu}m$.

• Clean Technology
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• v.25 no.4
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• pp.316-323
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• 2019

In order to enhance combustion efficiency and reduce atmosphere pollutants, it is essential to measure carbon monoxide (CO) concentration precisely in combustion exhaust. CO is the important gas species regarding pollutant emission and incomplete combustion because it can trade off with NOx and increase rapidly when incomplete combustion occurs. In the case of a steel annealing system, CO is generated intentionally to maintain the deoxidation atmosphere. However, it is difficult to measure the CO concentration in a combustion environment in real-time, because of unsteady combustion reactions and harsh environment. Tunable Diode Laser Absorption Spectroscopy (TDLAS), which is an optical measurement method, is highly attractive for measuring the concentration of certain gas species, temperature, velocity, and pressure in a combustion environment. TDLAS has several advantages such as sensitive, non-invasive, and fast response, and in-situ measurement capability. In this study, a combustion system is designed to control the equivalence ratio. Also, the combustion exhaust gases are produced in a Liquefied Petroleum Gas (LPG)/air flame. Measurement of CO concentration according to the change of equivalence ratio is confirmed through TDLAS method and compared with the simulation based on Voigt function. In order to measure the CO concentration without interference from other combustion products, a near-infrared laser at 4300.6 cm^-1 was selected.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.69-84
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• 2023

Despite the continuous installation and regular inspection of waste treatment facilities, complaints about excessive incineration and illegal dumping stench continue to occur at on-site treatment facilities. In addition, field surveys were conducted on the waste treatment facilities currently in operation (6 type) to understand the waste treatment process for each field, to grasp the main operating factors applied to the inspection. In addition, we calculated the material·energy balance for each main process and confirmed the proper operation of the waste disposal facility. As a result of the site survey, in the case of heat treatment facilities such as incineration, cement kilns, and incineration heat recovery facilities, the main factors are maintenance of the temperature of the incinerator required for incineration and treatment of the generated air pollutants, and in the case of landfill facilities Retaining wall stability, closed landfill leachate and emission control emerged as major factors. In the case of sterilization and crushing facilities, the most important factor is whether or not sterilization is possible (apobacterium inspection).In the case of food distribution waste treatment facilities, retention time and odor control during fermentation (digestion, decomposed) are major factors. Calculation results of material balance and energy resin for each waste treatment facility In the case of incineration facilities, it was confirmed that the amount of flooring materials generated is about 14 % and the amount of scattering materials is about 3 % of the amount of waste input, and that the facility is being operated properly. In addition, among foodwaste facilities, in the case of an anaerobic digestion facility, the amount of biogas generated relative to the amount of inflow is about 17 %, and the biogas conversion efficiency is about 81 %, in the case of composting facility, about 11 % composting of the inflow waste was produced, and it was comfirmend that all were properly operated. As a result, in order to improve the inspection method for waste treatment facilities, it is necessary not only to accumulate quantitative standards for detailed inspection methods, but also to collect operational data for one year at the time of regular inspections of each facility, Grasping the flow and judging whether or not the treatment facility is properly operated. It is then determined that the operation and management efficiency of the treatment facility will increase.