• Applied Biological Chemistry
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• v.45 no.2
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• pp.84-91
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• 2002

If contaminated river water is sprayed over the floodplain, organic matter and nitrogen would be removed by microbial processes in the rhizosphere of vegetation during the filtration through soil. In this study we tested the organic matter and nitrogen removal from contaminated river water by the floodplain filtration. Model system of floodplain was constructed using a PVC pipe (15 cm i.d. ${\times}$ 150 cm L) which was packed with a loamy sand soil collected from a floodplain in Nakdong river. The model system was instrumented with soil solution samplers and gas samplers. A river water collected from Omogcheon in Kyongsan was sprayed from top of the model system at three different rates. The concentration of organic matter, DO, $NO_3^-$, $NO_2^-$, $NH_4^+$, $N_2$ and $N_2O$, and redox potential were measured as a function of soil depth for 24 days after the system reached a steady state. When river water was sprayed at the rates of 40.8 and 68.0 $l/m^2/day$, a significant reductive condition for denitrification was developed at below 5-cm depth of the soil. When the water reached at 90-cm depth of the soil, COD and concentration of inorganic nitrogen were lowered, on an average, from 18.7 to 5 mg/l and from 2.7 to 0.4 mg/l, respectively. $N_2$ comprised most of the N gas evolved from denitrification and $N_2O$ concentrations emitted at the surface of soil were less than 1 {\mu}l/l. The effective removal of organic matter and nitrogen by the filtration in the model system of floodplain demonstrates that the native floodplains, which include rhizosphere of vegetation at the top soil, could be more effective in the treatment of contaminated river waters and other industrial waste waters containing high concentration of organic matter and nitrogen.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.620-627
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• 2005

In this study, life cycle assessment (LCA) on one of corrugated cardboard box as functional unit was carried out. System boundary of this study divided according to raw material acquisition, corrugated cardboard manufacture and corrugated cardboard box manufacture stage. And environmental impacts are evaluated on each stage and sub-process. The impact categories are classified into eight categories of abiotic resource depletion, global warming stratospheric ozone depletion, photochemical oxidant creation, air acidification, eutrophication, ecotoxicity and human toxicity. From the results, it is found that environment impacts at raw material acquisition stage is the highest as about 92% of whole stage due to liner board manufacture stage. The highest environmental impacts at sub-process of corrugated cardboard and box manufacture stage is a single facer and D/W backer process that included as main process in corrugated cardboard manufacture, and is caused by used energies like electricity, B-C oil, and etc. And then diagnosis for clean production process system of package is carried out. Through diagnosis, on loss rate is reduced and inner pressure intensity of box is improved. After improvement, environmental impact was decreased about 3.8% compared with before improvement.

• Fire Science and Engineering
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• v.16 no.1
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• pp.1-7
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• 2002

Halogen-based fire suppressing agents have environmental problems because they cause the stratospheric ozone depletion and globe warming. Hence, fire suppression system using fine water mist became the center of interest as a substitution of halon. As a study about this, it is in progress to make the optimum droplet size by using water mist nozzles and to improve the extinguishing performance of water mist by using additives. Before this study, the extinguishing time of ethanol and n-heptane pool fire was measured with changing of water mist droplet size, flow density, discharge pressure, and fire size. In this study, on adding the additives to improve physical and chemical extinguishing performance of water mist, the extinguishing performance would evaluate and the optimum condition would find out. As a result, in case of ethanol pan 1 pool fire, the extinguishing time of the water mist by adding of 2.5 wt% NaCl and 0.3% AFFF got shorter 27% and 60% than the pure water mist. Adding of AFFF was to decrease the flame temperature by forming thin film on the fuel surface and to decrease the evaporation of n-heptane fuel. In case of NaCl, alkali salt crystals showed on the flame surface.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.5
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• pp.499-508
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• 2010

This study proposed a life cycle impact assessment index that can indicate the environment-related information of the product in monetary value such that the national geographical, environmental, and social features are fully reflected based on a damage-oriented model. First, the estimation process was classified into characterization, damage assessment, and integration stages considering the six biggest impact categories: resource depletion, global warming, ozone depletion, acidification, eutrophication, and photochemical oxidant creation. Moreover, this study came up with the 16 category endpoints related to the 6 impact categories, and the damage function, to the 4 largest safeguard subjects. The integration indices of finally identified impact categories were KRW 21.8/kg Sb, KRW 6.19/kg$CO_2$, KRW 53,000/kg CFC-11, KRW 13,100/kg $SO_2$, KRW 2,310/kg ${PO_4}^{3-}$, and KRW 3,030/kg $C_2H_4$. Using the results of this research, environmental impacts based on the environmental load generated throughout the entire life cycle of a product can serve as a single index in monetary value; thus enhancing understanding and utilization of the results of life cycle impact assessments.

• Journal of Korean Society of Archives and Records Management
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• v.15 no.2
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• pp.165-179
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• 2015

Archives have historical and academic values. That is why the study of preservation conditions and the environment for the effective management of various records progress. However, materials such as paper and adhesives will inevitably cause biological damages. These damages spread into the inner side of archives, which would make it impossible to recover. For example, archival records from Malaysia and Oman are easily exposed to biological damage because of these countries' hot and humid climate. As such, once records are damaged, disinfection operations are customary in these areas. Methyl bromide (MeBr) and ethylene oxide (EtO) were used in the disinfection process as they showed good insecticidal effect. However their antibacterial effect are negligible. As such, the need for an environmental-friendly fumigator was evident. An environmental-friendly fumigator is designed to improve storage stability. Such equipment is expected to contribute to prevention of damages to cultural heritages through its use of vaporization technology, maintenance of a disinfection space (chamber), and self-generation of nitrogen.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.800-805
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• 2016

Rapid growth in nanotechnologies promises novel benefits through the exploitation of their unique industrial applications. However, as the production volume of nanomaterials increases, their unintentional exposure to the environment has been occured. Potential impacts of nanoproducts on the environment can be evaluated in the life cycle assessment (LCA). LCA is the systematic analysis of the resource usages and emissions over the life time from the primary resources to the moment of disposal. In this study, we performed LCA for fabrication processes of superhydrophilic oil/water separator using nano-$TiO_2$. $TOTAL^{TM}$ freeware was used to analyze for all fabrication processes, and 6-environmental impact factors (resource depletion, climate change, ozone depletion, acidification, eutropication, and photochemical oxidation) were introduced. In addition, the use of nano-$TiO_2$ in the fabrication of superhydrophilic oil/water separator was actively contributed to the environmental impact factors, compared to the bulk-$TiO_2$.

• Korean Journal of Construction Engineering and Management
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• v.16 no.3
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• pp.49-58
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• 2015

In order to determine how much a new green building reduce the environmental impacts, it is necessary to establish the reference target for comparison. Therefore, this study aims to establish the reference target by evaluating the environmental impacts of existing buildings. To ensure this end, this study evaluated the environmental impacts(Global warming potential, ozone layer depletion potential, acidification potential, eutrophication potential, photochemical ozone creation potential, and abiotic depletion potential) of 17 existing elementary school buildings, which are located in Seoul, Busan, Daegu, and Gwangju, by using the hybrid LCA model. As a result, the environmental impacts of the case buildings were clearly distinguished in different regions. Therefore, this study presented the reference targets which are appropriate to each region. For example, the reference targets for global warming potential, which can be used in Seoul, Busan, Daegu, and Gwangju, are 3.76E+03, 1.90E+03, 2.63E+03, $2.81E+03kg-CO_2\;eq./m^2$, respectively. The presented reference targets are expected to be useful for understanding how much environmental impacts can be reduced when a new green school building is constructed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.868-873
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• 1997

Nitrifier consortium entrapped in Ca and Ba-alginate beads were packed into two reactors and studied for removing ammonia-nitrogen in aquaculture system. The ammonia-nitrogen concentration of the influent was continually kept about 2 ppm. At the hydraulic residence time of 0.6 hours, ammonia-nitrogen removal amount of two reactors was about 52.6 and 51.0 g $NH_3-N/m^3/day$, respectively. The ability of adjusting to an impulsive leading which was happened according to variations of HRT was better at Ba-alginate reactor, but its discrepancy was not so large. At the respect of removing ammonium-nitrogen, two reactors showed the similar ability of treating recirculating water.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.698-705
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• 2017

Environmental impact of a mobile phone charger containing recycled plastic was quantified using LCA and the environmental benefits from the use of recycled and virgin plastic were compared. The assessment considers potential environmental impacts across the whole life cycle of the charger including; pre-manufacturing; manufacturing; distribution; product use; and end-of-life stages and quantified six environmental impact categories; Abiotic depletion; Acidification; Eutrophication; Global warming; Ozone layer depletion; and Photochemical oxidants creation. The study showed that the environmental impacts of the use stage accounted for 94.4% and 70% in the resource depletion and global warming impact categories, respectively, and the environmental impacts of the pre - manufacturing stage accounted for more than 98% in the other impact categories. The main cause of the environmental impacts in the use stage was electricity consumed by the charger. The main cause in the pre-manufacturing stage was PBA (Printed Board Assembly) and external case manufacturing. In order to quantify the environmental benefits of recycled PC (Polycarbonate) in the exterior case, the environmental impacts of 1 kg production of recycled PC and virgin PC were evaluated. The environmental impact on the abiotic depletion of the recycled PC is estimated to be 30% compared to the virgin PC, and the impacts on the other impact categories of the recycled PC were less than 5% of the virgin plastic. Sensitivity analysis was performed for 12 items including site data and assumptions made. The sensitivity of each item was less than 10%. The results of this study confirm that designing compact and light PBA, improving charging efficiency, and use of recycled plastic are important design factors to reduce the environmental impact of a charger.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.494-500
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• 2006

Life Cycle Assessment(LCA) is an environmental assessment tool for evaluating environmental burdens associated with products, processes and activities from the raw material acquisition stage to the end-of-life stage. End-of-life stage as well as other processes requires a reliant database in order to increase the confidence in the LCA results. In this study, the flow of Personal Computer(as PC) in the end-of-life stage was examined and the database of two scenarios has been established, i.e. one is part reuse and the other is no part reuse, in the end-of-life phase of PC. Also, key environmental issues were identified by carrying out LCA on a PC in the end-of-life phase for eight environmental impact categories. The 'ozone layer depletion' contributes the highest environmental impact due to generation of $Cl_2$ gas during the incineration of waste plastics. In addition, the scenario 1(part reuse) is more environmentally sound than the scenario 2(no part reuse) when comparing two scenarios.