An extract of fresh guava leaves (Psidium guajava) was used as a green carbon precursor to fabricate blue fluorescent carbon quantum dots (GCQDs) by hydrothermal process. The GCQDs show bright blue fluorescence emission under UV light with an excitation wavelength of 350 nm and emission at 450 nm. The physical structure of GCQDs was characterized by Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), High-resolution transmission electron microscope (HR-TEM) and atomic force microscopy (AFM). GCQDs 80 μg inhibited the growth of waterborne pathogens Escherichia coli and Salmonella typhi. We also investigated the catalytic activity of the GCQDs on the removal of two azo dyes, namely Congo red and bromophenol blue, with and without NaBH4. The GCQDs showed an excellent reduction of color intensity of both dyes without NaBH4 within 30 min of treatment.

본 실험에서는 대청호에서 발생한 남조류를 대상으로 SiC(Silicon carbide) 평막의 최적 운전조건을 도출하고자 하였다. 이를 위해 원수 농도에 따른 투과플럭스, 응집제 주입 조건, Air scrubbing 조건, 역세척(Backwashing) 유량 및 시간, 여과 및 역세척 시간, 응집제 종류 및 주입 농도 등에 대해 안정적으로 운전이 가능한 최적 조건을 도출하였다. 특히, 저농도의 응집제 주입에도 음전하를 띄는 조류 입자들과 전기적으로 중화를 일으켜서 생성된 미세 플럭들이 SiC 평막의 막표면에서 투수성을 증가시킨 것으로 사료된다. 이를 통해 도출된 설계인자로 제작한 Pilot Plant를 조류 제거시 적용하고자 한다. 본 연구는 환경부의 “환경정책기반공공기술개발사업”으로 지원받은 과제입니다.

To improve stability of the water resources that were seriously affected by climate change and various environmental effects and to supply the clean water always, continuous efforts are essential. Provision of measures with respect of hardware is basically essential to improve the water resources stability due to the topographic characteristic in Korea. However, building a new dam becomes gradually very difficult because of a hardship in selecting right places, opposition forces such as environment and local residents, negative publicity for large civil engineering projects, and so on. The present study, therefore, proposes the Blue dam as an alternative for securing the water resources of a new concept considering domestic conditions. To evaluate the effect of the Blue dam, the Hec-ResSim model is used and the probabilistic discharge flow rate is applied. As a result, when Dam Yeongcheon is applied as a study area, securing water resources of 14 million tons are predicted be secured and the flood control of 15.4 million tons is expected, in comparison with operation of the existing dam only. Consequently, Blue dams are supposed to carry out the function of securing water resources, controling flood, maintaining eco-environmental instream flow, generating hydroelectric power, and providing spaces for recreational activities.

Understanding the temporal variability of agricultural parameters derived from historical climate data is important for planning in agriculture. Therefore, this study assessed the magnitude and recent trends of the transpiration ratio defined as the crop water use per harvested yield for the period from 1980 to 2010. The crop water use was estimated using the Food and Agriculture Organization’s Crop Wat model for eight administrative provinces in Korea. The temporal trends and spatial uncertainty were explored using the Mann-Kendall and Theil Sen’s methods. The regional average rice yield was 6.31 t ha-1(range 5.9 to 6.9 t ha-1). The results showed that the rice yield in Korea increased by 26 kg ha-1yr-1. Overall, the regional average transpiration ratio was 1,298 m3 t-1 (range 1,162 to 1,470 m3 t-1). From 1980 to 2010, the transpiration ratio decreased by 8.2 m3 t-1 (range 2.7 to 14.4 m3 t-1), largely as a result of the increasing yield. The statistical approach to historical data used in this study also provides a basis for simulating the future transpiration ratio.

최근 내수면양식장의 BFT 양식 배출수의 도시농업용 활용에 관한 연구가 활발하게 본 연구진에 의해 진행되어지고 있다. 하지만 도시농 업용으로 한정된 연구에서 비료가 다량으로 사용되어 지고 있는 과수에의 활용에 대한 연구 필요성이 대두되어 누구나 가정에서도 재배가 가능한 블루베리에서 BFT 배출수의 효과를 구명하여 보고자 본 연구를 수행하였다. BFT 배출수는 내수면양식연구센터 틸라피아를 양식 하고 있는 양식조의 물을 채취하여 무처리, 농장 관행법, 배출수 원액, 배출수 1/2희석액, 배출수 1/4 희석액 시비 등 5처리로 실험하여 다음 과 같은 결론을 얻었다. 블루베리의 총생산량과 과립당 무게는 처리간 유의성이 없어 배출수가 기존의 비료를 대체하여도 블루베리 열매 의 생육에 영향을 주지 않아 비료로서의 이용가능성이 있었음을 확인하였다. 그리고 과실내 무기성분의 변화에서는 나트륨과 철의 함량이 높게 나와 이를 줄일 수 있는 배출수 비료화의 또 다른 연구 점을 보여주고 있다. 블루베리의 고유 기능성 물질인 안토시아닌의 함량 결과에 서는 처리에 따른 일관성을 보이고 있지 않아 기능성물질의 변화에도 배출수의 처리가 나쁜 영향을 보이지 않음을 알 수 있어 블루베리의 재배에 있어서도 배출수의 비료활용도는 가능성이 있다는 결론을 얻을 수 있었다. 하지만 비료로서의 사용가능성을 더 높이기 위해서는 보다 정제된 배출수의 사용과 효과를 얻기 위해서는 배출수의 가공적 연구가 더욱 필요하다고 판단된다.

In order to understand the impact for decomposition of blue-green algae Microcystis on water quality, the algae were cultivated with collection of natural population during approximately one month, when water-bloom of Microcystis dominated at August 31, 1999 in the lower part of the Okchon Stream. The enrichment of inorganic N·P nutrients didn't in algal assay and the effect of Microcystis on water quality was assessed from the variation of nutrients by algal senescence. Microcystis population seemed to play a temporary role of sink for nutrients in the water body. Initial algal density of Microcystis was 2.3×106 cells/ml. When Microcystis population died out under light condition, algal N·P nutrients between 9∼12 days affected to increase of biomass after reuse by other algal growth as soon as release to the ambient water. However, cellular nutrients under dark condition were almost moved into the water during algal cultivation. NH4, NO3 and SRP concentration were highly increased with 160, 17 and 79 folds, respectively relatve to the early. As a result, the senescence of Microcystis population seemed to be an important biological factor in which cause more eutrophy and increase of explosive algal development by a lot of nutrients transfer to water body. There are significantly observed an effort of reduce for production of inner organic matters such a phytoplankton as well as load pollutants from watershed in side of the water quality management of reservoir.

Recently, upwelling of anoxic bottom water mass have been frequently observed in northeast part of Tokyo Bay in Japan during summer to autumn. Since the colour of water surface becomes milky-blue or milky-green, the upwelling phenomenon is called `Blue Tide`. The data analysis of field surveys during `Blue Tide` appearance have been performed for understanding the physical features of the `Blue Tide` phenomena in Tokyo Bay. It becomes clear that (1) the formation of the anoxic bottom water correlates well with the temperature difference between the surface and bottom waters, (2) there are two necessary conditions for generating `Blue Tide` ; that is, strong stratification and off-shore wind. The strong southwest(on-shore) wind before the `Blue Tide` appearance may play an important role to make the stratification strengthen. When these conditions are larger and the northeast or east-northeast (off-shore) wind stronger than 5 m/s blows in succession, the `Blue Tide` upwelling appears at the head of Tokyo Bay.