• Journal of the Institute of Convergence Signal Processing
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• v.16 no.3
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• pp.108-114
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• 2015

Ballast water is carried by ships to ensure stability, trim and structural integrity. When a ship loads cargo, the ballast water is discharged. When foreign marine microorganisms are introduced into new marine environments, they pose a threat to the local marine ecological system. UV system is commonly used for the disinfection of waste and surface water. This method would not be as efficient because some species do survive to form viable populations, much of the sediment and organisms at the bottom of tanks, and may become serious pests. In this paper, we designed and implemented ballast water treatment system using fuzzy PID controller to prevent lamp damage, and to reduce the formation of the viable populations. The experiments were conducted with ballast water treatment system using fuzzy PID controller with short time exposure to the temperature above $40^{\circ}C$. This system was shown to be effective by significantly reducing bacterial population and lamp life extension through appropriate temperature of ballast water.

• Journal of Environmental Impact Assessment
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• v.26 no.6
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• pp.508-523
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• 2017

This study monitored the changes before and after restoration of ecological stream focusing on the places which are applied Sustainable Structured wetland Biotop (SSB) system and ecological Fish-way for restoration of Maeno stream. A total of 11 species and 191 individuals of fishes were founded out which were not verified inhabitation before restoration at SSB wetlands. Especially, it was could identified that micro habitat and healthy Fish-way was created because the restored target species, Microphysogobio yaluensis and Iksookimia koreensis were identified that habitation was monitored in SSB wetland. Amphibian have been restored to a number of Rana nigromaculata found in and around wetlands at the time of the third survey, which is highly active after restoration. Specified endangered species class 1 and natural monuments designated by the Ministry of Environment, Lutra lutra lutra, as a Mammalian, uses the wetlands and ecological Fish-way as habitat areas, and the his habitat is restored. In the case of Flora, vascular plants emerging in the survey area were increased to 7 and 13 species before restoration and 15 and 19 species directly after restoration, and 22 species and 33 species after restoration. Vegetation after restoration was found to be a basic producer of various ecosystems and a plant community that contributes to the purification of water quality such as Phragmites japonica communities. As the result of water quality monitoring, the average of treatment efficiencies were BOD 64.3%, T-N 47.2%, T-P 80.7%. Successful treatment of the nonpoint pullution source, which is a limiting factor to disturb the ecosystem, creatively restored the target species in the water quality class I, II.

• Journal of Ecology and Environment
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• v.37 no.1
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• pp.13-19
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• 2014

The effect of different turnover time of water on the decomposition of emergent macrophyte litter (Zizania latifolia Griseb.) was investigated using a microcosm experiment. Microcosm treatment represented different turnover time of water; 1, 2, 4 and 8 weeks. The litterbags from each treatment were retrieved every 2 weeks until the 8th week and the water simultaneously sampled with the litterbag. The dry weight and the content of major cations in the litter, and the content of available N, P, and major cations in the water were analyzed. Dry weight loss after 8 weeks indicated the lower decay rates under the condition of short turnover time of water. Major cations from the litter and the water showed that the leached amounts of K and Mg from the litter were highest in the 2nd week and dramatically decreased from the 4th week. The dynamics of available nitrogen and phosphorus in the water showed that as the water turnover time was getting longer, the amounts of available nitrogen and phosphorus remained higher. These results suggest that wetlands with longer turnover time of water could maintain the increased nitrogen and phosphorus and no outflow of the nutrients could cause eutrophication problem.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.489-497
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• 2006

The feasibility of the Natural and Ecological Wastewater treatment System (NEWS) was examined for rural wastewater treatment in Korea. The intermittent trickling biofilter with high hydrophilic filter media was used for pretreatment for suspended solids and organic pollutants. The subsequent constructed wetland with porous granule materials was used for promoting nutrient removal. The results show that the removal efficiencies of the system were high with respect to the water quality parameters except COD. Even if the effluent from the biofilter did not meet the guidelines for wastewater treatment plant effluent in Korea in terms of $BOD_5$ and TN, the final effluent of the system meets the guidelines us to good performance of the constructed wetland. The regression analysis between pollutant loading rate and removal rate indicated that the system could have stable removal for SS, $BOD_5$, TN, and TP in the given influent ranges. The analysis in the winter period indicated that the wetland covered with transparent polycarbonate glass had the statble performance during the winter period dus to increase of temperature inside the wetland without any heating system. With the stable performance, effective poilutant removal, low maintenance, and cost-effectiveness, the NEWS could be considered as an alternative treatment system for decentralized regions and rural communities in Korea.

• Journal of Ecology and Environment
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• v.41 no.11
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• pp.318-327
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• 2017

Background: A typical sewage treatment plant is designed for organic and nutrient removal from municipal sewage water and not targeted to eliminate micropollutants such as pesticides, pharmaceuticals, and nano-sized metals which become a big concern for sustainable human and ecological system and are mainly discharged from sewage treatment plant. Therefore, despite contaminant removal by wastewater treatment processes, there are still remaining environmental risks by untreated pollutants in STP (sewage treatment plant) effluents. This study performed aquatic toxicity tests of raw wastewater and treated effluents in two sewage treatment plants to evaluate toxicity reduction by wastewater treatment process and analyze concentration of contaminants to reveal potential toxic factors in STP effluents. Methods: Water samples were collected from each treatment steps of two STPs, and acute and chronic toxicity tests were conducted following USEPA (United States Environmental Protection Agency) and OECD (Organization for Economic Cooperation and Development) guidelines. Endpoints were immobility for mortality and reproduction effect for estrogenicity. Results: Acute $EC_{50}s$ (median effective concentration) of influents for Seungki (SK) and Jungnang (JN) STPs are $54.13{\pm}32.64%$ and $30.38{\pm}24.96%$, respectively, and reduced to $96.49{\pm}7.84%$ and 100%. Acute toxicity reduction was clearly correlated with SS (suspended solids) concentration because of filter feeding characteristics of test organisms. Chronic toxicity tests revealed that lethal effect was reduced and low concentration of influents showed higher number of neonates. However, toxicity reduction was not related to nutrient removal. Fecundity effect positively increased in treated wastewater compared to that in raw wastewater, and no significant differences were observed compared to the control group in JN final effluent implying potential effects of estrogenic compounds in the STP effluents. Conclusions: Conventional wastewater treatment process reduced some organics and nutritional compounds from wastewater, and it results in toxicity reduction in lethal effect and positive reproductive effect but not showing correlation. Unknown estrogenic compounds could be a reason causing the increase of brood size. This study suggests that pharmaceutical residues and nanoparticles in STP effluents are one of the major micropollutants and underline as one of estrogenic effect factors.

• Journal of Korean Society on Water Environment
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• v.20 no.4
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• pp.346-351
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• 2004

Because of being produced a great deal of excess sludges from biological wastewater treatment process, the subject regarding treatment and disposal of them has been significantly handled in real plants. It should be considered the alternative treatment with easy operating and cost effective process in rural areas. For the thickening of wasted activated sludge from small scale wastewater treatment facilities, thus, the provisional sludge thickening system was developed by the application of mesh filter module. Three meshes with different pore size(100, 150, $200{\mu}m$) were prepared for filter modules that were used to withdraw effluent from thickening system. A filter module with $100{\mu}m$ mesh was chosen as the most effective thickening material in the viewpoint of volume reduction and effluent quality: the volume reductions of initially injected sludge with 3,600 mg/L and 9,100 mg/L were 95% and 85%, respectively, and the filtered effluents were enough good to be shown below 1.0 mg/L of SS and 1.0 NTU of turbidity. Since the filtration of thickening was influenced by the cake layer formed on mesh filter module and this system was operated in the combination of sludge thickening with gravity settling, the filter modules with smaller pore size and the larger floc size were required for long term operation safely.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.651-651
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• 2015

The Because reduction facilities of existing non-point pollution source weren't balanced with each element technologies, most of case were what damaged scene nature of river, neutralized pollution sources and reduction effect. Therefore it's necessary to find a solution by integrating the operation system. Based on the comparative analysis that we have ran, we examined the capacity at individual operation's water purification and linked the treatment to detention pond, wetland and revetment.

• Journal of Environmental Health Sciences
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• v.39 no.5
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• pp.474-481
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• 2013

Objectives: This study was conducted to investigate the application of microbial fuel cells (MFCs) to the wastewater treatment systems employed in the Living Building Challenge. Methods: I reviewed a range of information on decentralized wastewater treatment technologies such as composting toilets, constructed wetlands, recirculating biofilters, membrane bioreactors, and MFCs. Results: The Living Building Challenge is a set of standards to make buildings more eco-friendly using renewable resources and self-treating water systems. Although there are various decentralized wastewater treatment technologies available, MFCs have been considered an attractive future option for a decentralized system as used in the Living Building Challenge. MFCs can directly convert substrate energy to electricity with high conversion efficiency at ambient and even at low temperatures. MFCs do not require energy input for aeration if using open-air cathodes. Moreover, MFCs have the potential for widespread application in locations lacking water and electrical infrastructure Conclusions: This paper demonstrated the feasibility of MFCs as a novel decentralized wastewater treatment system employed in the Living Building Challenge.

• Membrane and Water Treatment
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• v.10 no.2
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• pp.149-154
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• 2019

The information matter-element system was built to assess safety of water source. Based on the thought of multiindex fusion, fuzzy matter-element model evaluating water source behavior was constructed by matter-element transform. This model can process comprehensively hydrogeological data, ecological environment, water pollution, surface disturbance, and so on. Water source safety behavior can be described by the qualitative and quantitative manners. According to the development trend of quantitative results, water source safety behavior can be expressed dynamically. As an example, the proposed method was used to assess safety status of 7 water sources in the region. The numerical example shows that the proposed method is feasible and effective, and the evaluation results are reasonable.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.30 no.2
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• pp.90-100
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• 2012

This study centering on 10 village - Bangjuks analyzed multifunctionality value of village Bangjuks which have been main water treatment system in Korean traditional villages. On the basis of understanding the structure and character of components such as the well, common spring, village waterway and others which making water-flow and consisting of aquatic system in Korean traditional village Bangjuk, the conclusion as the instrumental device of social and ecological role and ecological watershed management, securing the ecosystem soundness of the damaged or deteriated aquatic ecosystem due to the industrialization and urbanization is as below; 1. The traditional village Bangjuk was environmentally friendly hydraulic system which gathers waterways of village into a point including sewage water, retains and flows out to village through agricultural waterway. Through this Bangjuk, they have managed sewage and rainfall runoff flowed out village efficiently. It is not only a detention system of water but a kind of eco-friendly system that flow out water into the rivers after reusing and filtering it. 2. Around five traditional villages and five villages after modernization, this study classified the types of village Bangjuk as three types considering geographic location, size, etc; marsh type of low swamp, high water -low rice field type of natural flow stucture, low water - high rice field type requiring artificial irrigation facility. All the five traditional villages were turned out to be marsh type of low swamp. Geoji, Sanjeri, Ma-am, Yangchon of the agricultural villages were high water-low rice filed type, and Sangchoenri village was classified low water-high rice field type. 3. This study checked up the function of water purification of village Bangjuk. In Wonteo and Geji villages affected by discharge of village sewer and domestic sewage, the efficiency of ammonia nitrogen($NH_3-N$) and total phosphorus(T-P) was 56~95%, which was high. In Sangcheonri and Sanjeri villages strongly affected by stall and farmland, the efficiency of suspended solids(SS) was 70~85%, and that of total nitrogen(T-N) and total phosphorus(T-P) was 5.3~65%. 4. A water purification system can be found out in the system of village Bangjuk that filter out village sewage and rainfall runoff flowed through the settle and filter of pollution source and denitrification of plants. Through this system of village Bangjuk, it must be used as the basic facilities for the ecological watershed management. The sewage management system of village Bangjuk as a eco-filter must be used and studied as an eco-friendly facility for the ecological watershed management around the subwatershed and catchment.