• Journal of the Korean Wood Science and Technology
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• v.35 no.1
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• pp.73-80
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• 2007

This study was carried out to separate the heavy toxic metals in eco-building materials by low-temperature pyrolysis, especially arsenic (As) compounds in CCA wood preservative as a solid in char. The pyrolysis was carried out to heat the CCA-treated Hemlock at $280^{\circ}C$, $300^{\circ}C$, $320^{\circ}C$, and $340^{\circ}C$ for 60 mins. Laboratory scale pyrolyzer composed of [preheater$\rightarrow$pyrolyzer$\rightarrow$1st water scrubber$\rightarrow$2nd bubbling flask with 1% $HNO_3$ solution$\rightarrow$vent], and was operated to absorb the volatile metal compound particulates at the primary water scrubber and the secondary nitric acid bubbling flask with cooling condenser of $4^{\circ}C$ under nitrogen stream of 20 mL/min flow rate. And the contents of copper, chromium and arsenic compounds in its pyrolysis such as carbonized CCA treated wood, 1st washing and 2nd washing liquors as well as its raw materials, were determined using ICP-AES. The results are as follows : 1. The yield of char in low-temperature pyrolysis reached about 50 percentage similar to the result of common pyrolytic process. 2. The higher the pyrolytic temperature was, the more the volatiles of CCA, and in particular, the arsenic compounds were to be further more volatile above $320^{\circ}C$, even though the more repetitive and sequential monitorings were necessary. 3. More than 85 percentage of CCA in CCA-treated wood was left in char in such low-temperature pyrolytic condition at $300^{\circ}C$. 4. Washing system for absorption of volatile CCA in this experiment required much more contacting time between volatile gases and water to prevent the loss of CCA compounds, especially the loss of arsenic compound. 5. Therefore, more complete recovery of CCA components in CCA-treated wood required the lower temperature than $320^{\circ}C$, and the longer contacting time of volatile gases and water needed the special washing and recovery system to separate the toxic and volatile arsenic compounds in vent gases.

• Land and Housing Review
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• v.2 no.4
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• pp.517-528
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• 2011

Indiscreet developments cause environmental problems in major cities of Seoul Metropolitan Area. Among the environmental problems, the air pollution leads the citizens' physical and economic damages. Therefore, it needs to predict how much air pollutant which is emitted from human activities can be carried by urban environment, then to examine the reasonable level of urban development This study assumed that the air pollution is represented differently by the amount of emission. With the assumption, the acceptable air pollutant emission which keeps the air quality under the environmental standard is estimated, then the proper population is calculated in the case of Gwacheon, Gyeonggi. The result is as follow: First, air pollution concentrations of CO, $NO_2$, $SO_2$ which are estimated by using IDW interpolation of GIS don't excess the air environmental standard. Second, the result of correlation analysis between air pollutant emission and air pollution concentration shows that CO and $NO_2$ has high correlationship with total source of pollution and linear source of pollution, and $SO_2$ with linear source of pollution. Third, the results of regression analysis show that the acceptable population is bigger that the real population in the case of CO, and with the estimation of $NO_2$ and $SO_2$, the current population in the urban center and boundaries where the residential and commerce land uses are concentrated is bigger than the acceptable population. The consequence of this study is that the estimation of carrying capacity can suggest the acceptable human activities which keep the air quality under the environmental standard. This can leads the sustainable urban development by control the human activities under the carrying capacity of urban environment.

• Journal of Preventive Medicine and Public Health
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• v.19 no.2 s.20
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• pp.252-262
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• 1986

In order to assess the degree of atmospheric pollution and to contribute the health improvement of residents in Pusan, the authors measured CO, $SO_2,\;NO_2$ and TSP level at 3 places by season and time from July, 1985 to April, 1986. The places were Somyon, Sasang and Daeshin-dong, which were known as the commercial, industrial and residental area in Pusan, respectively. The obtained results were as follows: 1) The average concentration of CO was highest with $2.19{\pm}0.52$(3.5-1.0)ppm at Sasang area, and lowest with $1.32{\pm}0.55$(3.0-0.5)ppm at Daeshin-dong areas. 2) The average concentration of $SO_2$ was highest with $0.092{\pm}0.073$(0.378-0.028)ppm at Sasang, and lowest with $0.041{\pm}0.014$(0.083-0.019)ppm at Daeshin-dong. 3) The average concentration of $NO_2$ was highest with $0.069{\pm}0.012$(0.090-0.050)ppm at Somyon, and lowest with $0.043{\pm}0.010$(0.061-0.032)ppm at Daeshin-dong. 4) The average concentration of TSP was highest with $300{\pm}130(780-130){\mu}g/m^3$ at Sasang, and lowest with $160{\pm}80(390-70){\mu}g/m^3$ at Daeshin-dong. 5) The level of CO and TSP were highest in summer at Somyon and Daeshing-dong, and in winter at Sasang, respectively. The level of $SO_2$ and $NO_2$ were highest in winter and spring at all areas. 6) The level of all air pollutants were higher in the afternoon or night than in the morning.

• Journal of Preventive Medicine and Public Health
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• v.30 no.3 s.58
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• pp.609-622
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• 1997

Nitrogen dioxide $(NO_2)$ has been regarded as one of the main elements among air pollutants, and we measured $NO_2$ levels of near gas range, kitchen, living room and outdoor on 489 apartments in Pusan area. $NO_2$ were sampled by using Palmes tubes (diffusion tube sampler) during August 16-25, 1995 (summer) and January 15-29, 1996 (winter), respectively. Authors wanted to know comparison of $NO_2$ levels in summer and winter, $NO_2$ levels categorized by variables, and variables affected to $NO_2$ levels. According to this study, we conducted to establish the degree of indoor-outdoor air pollution of urban apartments in Korea and methods to reduce indoor air pollution. The results of this study were summarized as follows: 1) Mean $NO_2$ levels of near gas range, kitchen, living room, and outdoor were $25.9{\pm}10.0ppb,\;23.3{\pm}8.0ppb,\;19.9{\pm}6.1ppb,\;and\;19.0{\pm}6.0ppb$ in summer, and $34.5{\pm}16.8ppb,\;28.2{\pm}13.4ppb,\;25.3{\pm}12.5ppb,\;21.8{\pm}9.8ppb$ in winter, respectively. 2) Mean $NO_2$ levels according to the floor levels were not significantly different in summer, and in winter, $NO_2$ levels were decreased as the floor levels were increasing, but those were increased above 16th floor. 3) Variables showing significant correlation(p<0.05) with $NO_2$ levels were as follows; Summer: floor level, family size, number of family during a meal, number using gas range during rice cooking per day, and natural ventilation. Winter: floor level, family size, number of person who have been respiratory disease in a house, number of family during a meal, total number of meals, and number using gas range during rice or side-dish cooking per day. 4) We suggest that the methods of reducing indoor $NO_2$ levels are ventilation during cooking, complete combustion, decreasing number and time of cooking, and substitution of fuels.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.929-936
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• 2011

To treat non-point source pollution in Dongbok lake, removal efficiencies of pollutants were investigated in Dongbokcheon constructed wetlands (CWs) at different treatment time and wastewater loading. The wetlands consisted of forebay, wetlands ($1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$, $5^{th}$, $6^{th}$, $7^{th}$, and $8^{th}$ wetlands) and sedimentation pond. The concentrations of BOD, SS, T-N, and T-P in inflow ranged $0.85{\sim}3.14mg\;L^{-1}$, $3.33{\sim}9.70mg\;L^{-1}$, $0.64{\sim}5.33mg\;L^{-1}$, and $0.03{\sim}0.10mg\;L^{-1}$ from April to October in 2008, respectively. The removal rates of BOD, SS, T-N, and T-P in Dongbokcheon CWs were 34%, 5%, 31%, and 13%, respectively. The removal rates of BOD and T-N were higher than those for SS and T-P. The amounts of pollutant removal in Dongbokcheon CWs were higher in the order of forebay > wetlands > sedimentation pond for BOD, sedimentation pond > wetlands > forebay for SS, sedimentation pond > forebay > wetlands for T-N. The amount of T-P removal in wetlands was higher than forebay and sedimentation pond.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.18-24
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• 2007

Paddy fields are apparently nonpoint source pollution and influence water environment. In order to improve water quality in rivers or lakes, to low nutrient load from paddy fields are required. To establish comprehensive plan to control agricultural non-point source pollution, it is imperative to get a quantitative evaluation on pollutants and pollution load from paddy fields. A field monitoring study was carried out to investigate the water balance and losses of nutrients from fields in Sumjin river basin. The size of paddy fields was 115 ha and the fields were irrigated from a pumping station. The observed total nitrogen loads from paddy fields were larger than those of the unit loads determined by Ministry of Environment data (MOE). It is because the nitrogen fertilization level at the studied field was higher than the recommended rate and the high irrigation and subsequent drainage amount. On the contrary, total phosphorus loads were less than those addressed by MOE since phosphorus fertilization level was lower than that of standard level. Therefore, it was found that fertilization, irrigation, and drainage management are key factors to determine nutrient losses from paddy fields. When the runoff losses of nutrients were compared to applied chemical fertilizer, it was found that 42 to 60% of nitrogen lost via runoff while runoff losses of phosphorus account for 1.3 to 7.6% of the total applied amount during the entire year.

• Clean Technology
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• v.27 no.4
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• pp.341-349
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• 2021

In combustion facilities, the nitrogen and sulfur in fossil fuels react with oxygen to generate air pollutants such as nitrogen oxides (NO_X) and sulfur oxides (SO_X), which are harmful to the human body and cause environmental pollution. There are regulations worldwide to reduce NO_X and SO_X, and various technologies are being applied to meet these regulations. There are commercialized methods to reduce NO_X and SO_X emissions such as selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR) and wet flue gas desulfurization (WFGD), but due to the disadvantages of these methods, many studies have been conducted to simultaneously remove NO_X and SO_X. However, even in the NO_X and SO_X simultaneous removal methods, there are problems with wastewater generation due to oxidants and absorbents, costs incurred due to the use of catalysts and electrolysis to activate specific oxidants, and the harmfulness of gas oxidants themselves. Therefore, in this research, microbubbles generated in a high-pressure disperser and reducing agents were used to reduce costs and facilitate wastewater treatment in order to compensate for the shortcomings of the NO_X, SO_X simultaneous treatment method. It was confirmed through image processing and ESR (electron spin resonance) analysis that the disperser generates real microbubbles. NO_X and SO_X removal tests according to temperature were also conducted using only microbubbles. In addition, the removal efficiencies of NO_X and SO_X are about 75% and 99% using a reducing agent and microbubbles to reduce wastewater. When a small amount of oxidizing agent was added to this microbubble system, both NO_X and SO_X removal rates achieved 99% or more. Based on these findings, it is expected that this suggested method will contribute to solving the cost and environmental problems associated with the wet oxidation removal method.

• Clean Technology
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• v.27 no.4
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• pp.367-371
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• 2021

The oxy-combustion system is one of the carbon recovery and storage technologies (CCS: Carbon capture & storage) that performs coal combustion using pure oxygen and recirculated flue gas. This is a technology that facilitates storage of carbon dioxide by generating an exhaust gas consisting of only carbon dioxide without a process of separating carbon dioxide and nitrogen when coal is burned using pure oxygen and recirculated flue gas mixture instead of a conventional air combustion system that produces carbon dioxide and nitrogen mixed exhaust gas. In this study, the characteristics of generated NO and SO₂ as atmospheric pollutants during oxy-combustion were examined using O₂/CO₂ mixed simulation gas. The reaction temperature was varied from 900 ℃ to 1200 ℃ and oxygen partial pressure was varied from 30% to 50%. The results showed that NO and SO₂ concentrations in flue gas increased as the oxygen concentration and the reaction temperature in the furnace increased. The partial pressure of CO₂ in flue gas also increased as the oxygen concentration and the reaction temperature in the furnace increased. As a results of comparing NO production of 30% O₂/CO₂ oxy-combustion with air combustion, NO in flue gas increased with reaction temperature in both experiments and NO of oxy-combustion was 40 ~ 80 ppm lower than that of air combustion.

• Journal of Wetlands Research
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• v.23 no.4
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• pp.327-341
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• 2021

The riparian eco-belt is an efficient technique that can reduce non-point pollution sources in the basin and improve ecological connectivity and health. In Korea, a legal system for the construction and management of riparian eco-belts is in operation. However, it is currently excluded that rivers and floodplains in dam reservoir that are advantageous for buffer functions such as control of non-point pollutants and ecological habitats. Accordingly, this study presented and analyzed a plan to select a site for an integrated riparian ecol-belt that comprehensively evaluates the water quality and ecosystem characteristics of each dam floodplain and riparian zone for the Daecheong Dam basin in Geum River watershed. First, the Daecheong Dam basin was divided into 138 sub-basin with GIS, and the riparian zone adjacent to the dam floodplain was analyzed. Sixteen evaluation factors related to the ecosystem and water quality impact that affect the selection of integrated riparian eco-belt were decided, and weights for the importance of each factor were set through AHP analysis. The priority of site suitability was derived by conducting an integrated evaluation by applying weights to sub-basin by floodplains and riparian zone factors. In order to determine whether the sites derived through GIS site analysis are sutiable for actual implementation, five sites were inspected according to three factors: land use, pollution sources, and ecological connectivity. As a result, it was confirmed that all sites were appropriate to apply integrated riparian ecol-belt. It is judged that the riparian eco-belt site analysis technique proposed through this study can be applied as a useful tool when establishing an integrated riparian zone management policy in the future. However, it might be necessary to experiment various evaluation factors and weights for each item according to the characteristics and issues of each dam. Additional research need to be conducted on elaborated conservation and restoration strategies considering the Green-Blue Network aspect, evaluation of ecosystem services, and interconnection between related laws and policy and its improvements.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.2
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• pp.124-134
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• 2021

Water in the Mulgol pond on Dokdo (island), Korea, was historically used for drinking water, but now it has been no longer used for this purpose due to regionally low water quality. Since 2007, this pond has been covered with a metal lid to protect from pollutants of seabirds, indicating limited light penetration into the Mulgol pond. Here, we investigated water quality in the pond and potential relationships of nitrogen components and microbes in May, June, August, and November 2020. The source salinity ranged from 1.39 to 1.57 psu. Suspended solids (0.8~5.1 mg L^-1) and chlorophyll-a (<0.01~0.49 ㎍ L^-1) remained low. The concentration of dissolved inorganic nitrogen (DIN) was between 35.9 and 47.2 mg L^-1. Thus, water in the Mulgol pond proves to be brackish water with low chlorophyll-a and high nutrients. This unique environment may be established by limited light intensity, sea fog (or seawater), and fecal pellets from many seabirds. Although the light source (800~8000 lux) was exposed to the four subsamples, chlorophyll-a concentrations were below <0.5 ㎍ L^-1 during the incubation periods. This result suggests that the biomass of phytoplankton does not increase along with an increase in light intensity. Furthermore, the content of nitrate constituted more than 90% of DIN, and a significant negative correlation between nitrate concentration and bacterial abundance was shown in May and June 2020 during the light exposure experiments (R=-0.762, p<0.05). Thus, it is possible that bacteria may be a significant agent to reduce nitrate concentration in the Mulgol pond, the relationship between nitrate concentration and bacterial abundance may vary seasonally.