• Title/Summary/Keyword: national environment

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Changes of Zooplankton Community in an Artificial Vegetation Island of Lake Paldang (팔당호에서 인공 수초재배섬 설치에 따른 동물플랑크톤 군집 변화)

  • You, Kyung-A;Park, Hae-Kyung;Byeon, Myeong-Seop;Jeon, Nam-Hui;Choi, Myung-Jae;Yun, Seok-Hwan;Kong, Dong-Soo
    • Journal of Korean Society on Water Environment
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    • v.23 no.3
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    • pp.339-347
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    • 2007
  • Zooplankton community dynamics were studied after establishment of an artificial vegetation island (AVI) in Lake Paldang, from April 2005 to November 2006. There were distinct seasonal and inter-annual changes of total zooplankton abundance at the survey site. Total zooplankton abundance rapidly increased in spring and fall, while it remained low throughout winter. During summer, the dynamics of zooplankton community seemed to be largely affected by hydrological parameters such as, precipitation and inflow. Total zooplankton abundance and biomass below AVI was much higher than that of pelagic zone (L1) in Lake Paldang. Copepoda and cladocera represented the main bulk of the zooplankton community from summer to fall at the both sites. Copepods were more dominant at AVI area, while cladocera were more dominant at pelagic zone (L1). Water quality, prey and habitat condition, species competition between zooplankton seemed to play important roles in dominance of the copepoda and cladocera in zooplankton community at AVI area. Our results conclude that artificial vegetation island provide the stable habitat and besides phytoplankton, diverse food to zooplankton, and consequently influence the diversity and richness of zooplankton community.

Efficiency Study of Measurement Method by Flow Duration (유황별 유속측정 방법에 따른 유효성 연구)

  • Ham, Sang In;Lee, Jeong Hwan;Kim, Dae Young;Ha, Don Woo;Kim, Yoon Soo;Jung, Kang-Young;Lee, Yeong Jae;Kim, Gyeong Hyeon;Kim, Young Suk
    • Journal of Korean Society on Water Environment
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    • v.34 no.5
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    • pp.462-469
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    • 2018
  • There are differences in method and cycle of flow rate survey depending on purpose of the operating department. To verify and use results of flow data according to the purpose, flow data of the directly measured and tele monitoring system were compared to verify validity. Flow measurement in the Ministry of Environment is aimed at setting up a standard flow of target water quality for water quality management and securing flow data of low and normal water level seasons for water quality evaluation. In this study, correlation analysis result ($R^2$) of same time zone data by direct measurement and tele monitoring system (TMS) at Seombon D point, a unit watershed of Seomjin river, for six years ('10 ~ '15) according to implementation of Total Daily Maximum Load (TDML) was wading 0.716, boating 0.962 and on bridge 0.943, and effectiveness of measurement method was verified by characteristics of flow duration as a season of dry and low-water; normal and high water are appropriate for wading, boating, and on bridge respectively. Results revealed it is reasonable to use directly measured results using the wading and boating method for low water level and dry seasons, and TMS data for rainy seasons. It can be used important data for future policy decisions.

Improved structures of stainless steel current collector increase power generation of microbial fuel cells by decreasing cathodic charge transfer impedance

  • Nam, Taehui;Son, Sunghoon;Kim, Eojn;Tran, Huong Viet Hoa;Koo, Bonyoung;Chai, Hyungwon;Kim, Junhyuk;Pandit, Soumya;Gurung, Anup;Oh, Sang-Eun;Kim, Eun Jung;Choi, Yonghoon;Jung, Sokhee P.
    • Environmental Engineering Research
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    • v.23 no.4
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    • pp.383-389
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    • 2018
  • Microbial fuel cell (MFC) is an innovative environmental and energy system that converts organic wastewater into electrical energy. For practical implementation of MFC as a wastewater treatment process, a number of limitations need to be overcome. Improving cathodic performance is one of major challenges, and introduction of a current collector can be an easy and practical solution. In this study, three types of current collectors made of stainless steel (SS) were tested in a single-chamber cubic MFC. The three current collectors had different contact areas to the cathode (P $1.0cm^2$; PC $4.3cm^2$; PM $6.5cm^2$) and increasing the contacting area enhanced the power and current generations and coulombic and energy recoveries by mainly decreasing cathodic charge transfer impedance. Application of the SS mesh to the cathode (PM) improved maximum power density, optimum current density and maximum current density by 8.8%, 3.6% and 6.7%, respectively, comparing with P of no SS mesh. The SS mesh decreased cathodic polarization resistance by up to 16%, and cathodic charge transfer impedance by up to 39%, possibly because the SS mesh enhanced electron transport and oxygen reduction reaction. However, application of the SS mesh had little effect on ohmic impedance.