• Proceedings of the Korean Environmental Sciences Society Conference
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• 2000.05a
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• pp.245-246
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• 2000

콩과식물인 전동싸리를 대상으로 통제된 조건하에서 Al과 Co처리에 따른 식물체의 생장반응과 식물체내 중금속의 축적정도 및 근류의 질소고정 활성의 변화를 조사한 결과 중금속은 Co가 Al보다 높게 축적되었고, 처리 초기에는 지하부를, 장기간 처리시는 광합성 기관의 생장을 억제했는데, Co 처리는 영향이 미약하였으나, Al처리구는 다소 심각한 영향을 주었으며, 생장에 비해 질소고정계의 피해가 현저하였다. 전동싸리는 흡수된 중금속을 뿌리수준에서 조절함으로써 광합성기관으로 이동을 억제하는 중금속에 대한 생장적응을 나타내었다. 결국 전동싸리는 30ppm의 중금속 처리시 뿌리 수준에서 조절함으로써 광합성기관으로 전이를 차단하여 금속에 대한 내성 나타내었고, Al이 Co보다 심각한 영향을 미치는 것으로 나타났다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.9 no.4
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• pp.179-195
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• 2004

The trophic state of the coastal waters of the southern part of Korea was assessed using biogeochemical data obtained from the National Marine Environmental Monitoring Program conducted by the National Fisheries Research and Development Institute for six years. The trophic state of different areas, analyzed by non-metric multi-dimensional scaling (MDS) analysis, could divide the areas into three groups. Masan Bay, with suboxic water masses and/or the highest concentrations of dissolved inorganic nitrogen and phosphorus occurred, was assessed as being in a hypertrophic state. Ulsan Bay, Onsan Bay, Busan and Jinhae Bay, located near strong point sources, were in a eutrophic state. Other areas, including Tongyong, Yosu, Mokpo and Jeju island, were evaluated as being in a mesotrophic state. During 1997 to 2002, the average values of excess nitrogen, which is the difference between the measured dissolved inorganic nitrogen (DIN) and the corrected DIN using the Redfield ratio, were positive at Ulsan, Onsan, and Busan, where there were inflows from polluted rivers. In contrast, those were negative values in Haengam Bay, Gwangyang Bay and nearby Yosu. This suggests that the limiting element for phytoplankton growth differed among sites. The time series data of excess nitrogen showed gradual decrease over time in the hypertrophic waters, but the opposite trend in the mesotrophic waters. This indicated that the ratio of nitrogen to phosphate varied according to the trophic state of the coastal waters. The enrichment of organic matter in sediment in eutrophic waters would disturb the normal pattern of biogeochemical cycling of nitrogen and phosphate. In order to assess the condition of the coastal environment, the benthic boundary layer should be considered.

• Korean Journal of Poultry Science
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• v.38 no.4
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• pp.255-263
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• 2011

This work was conducted to investigate the effects of phytase on the growth performance, excreta excretion, and N and P excretion of broilers for 7 weeks. One hundred ninety two Ross broiler (one-day-old) with average weight $44.7{\pm}1.5$ g were assigned randomly to 4 treatments groups (12 birds/pen, 4 pens/treatment) as $2{\times}2$ complex factors of sex of broiler male, female) and phytase 2 treatments (0, 300 FTU/kg), and fed experimental diets for 6 weeks (starter, 0~2 wk; earlier, 2~4 wk; finisher, 4~7 wk). The experimental diets included that phytase was added to the basal diet. Body weight was high at male treatment and at phytase treatment. Feed intake was high at male treatment and was no difference between phytase and non-phytase treatment. Feed efficiency was the highest at male and phytase treatment. Manure excretion was high at male treatment and reduced at phytase treatment. Excretion of N and P was high at male treatment and at non-phytase treatment. Finally, when phyase was added to basal diet, the growth performance of broilers was improved and excreta excretion and N and P excretion of broilers were decreased.

• Membrane Journal
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• v.28 no.1
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• pp.45-54
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• 2018

This study is to find the optimum draw solution in fertilizer-drawn forward osmosis desalination. Considering osmotic pressure, solubility, and pH, 20 blended fertilizers were screened. Their performance were evaluated in terms of pure water permeate flux, reverse solute flux, and specific reverse solute flux for nitrogen, phosphorus, and potassium. The pure water permeate flux of blended fertilizers including KCl were relatively higher. The reverse solute flux and specific reverse solute flux for nitrogen of blended fertilizers containing ${NO_3}^-$ ion were relatively higher than those of the nitrate ion-free draw solution. Those for phosphorus, and potassium of blended fertilizers including $NH_4H_2PO_4$, and $KNO_3$ were relatively higher than those of the phosphorus-free, and potassium-free draw solution, respectively. The blended fertilizer of $NH_4H_2PO_4$ and KCl contains all of nitrogen, phosphorus and potassium which are essential elements of fertilizer, and has the relatively high water permeation flux and the low reverse solute flux for nitrogen, phosphorus, and potassium. Therefore, it is the most effective draw solution for fertilizer-drawn forward osmosis desalination.

• Journal of Aquaculture
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• v.15 no.1
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• pp.15-21
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• 2002

Two groups of juvenile flounders (90 g/each) were fed on moist pellet feed thrice a day for a period of 8 weeks; the first group, reared in 4 circular (6m $\times$ 0.8 m) tanks (1200 flounders/tank), was fed daily (ED) and the second one on alternate days (EO). There was no significant difference in growth and feed conversion ratio (FCR) between these groups. There was also no difference in chemical composition, except in lipid, which was significantly higher (4.1%) in the ED group than the EO group (3.4%). Food intake and gain in the whole body nitrogen (N) were higher in the ED group but there was no significant difference between these groups in N retention; they excreted almost equal amount (114 vs 112 g) of N. Although phosphorus intake was significantly different between these groups, the flounders retained equal amount (0.5 g) of P in their body and excreted also equal amount (27.6 vs 26.0 g/kg weight gain) of p. Energy intake (2528 kJ) of the ED group was higher than that (2116 kJ) of the EO group. However, there was no significant difference in their energy retention efficiency. Clearly, alternate day feeding regimen led to more efficient utilization of food by the juvenile flounder.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.206-214
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• 2005

This study was initiated to evaluate efficiencies of suspenced-growth processes(CAS; Conventional Activated Sludge, MLE; Modified Ludzack-Ettinger) and hybrid process(Modified-Dephanox) on removal of organic matter(C), nitrogen(N) and phosphorus(P) in municipal wastewater. M-Dephanox process was designed to improve the performance of Dephanox process on denitrification efficiency. As the results, removal efficiencies of total chemical oxygen demand(TCOD), total nitrogen(T-N) and total phosphorus(T-P) in M-Dephanox process, which is hybrid process, were 12,3, 18.6 and 28.2% higher than those in MLE, which is suspended-growth process. The better removal efficiencies of TCOD, T-N and T-P in M-Dephanox than those in MLE result that M-Dephanox is not only hybrid or multi-sludge process but also process using biosorption mechanism which is possible to use organics in denitrification, effectively. Ammonia removal efficiency in nitrification reactor of M-Dephanox was 96.7% at short hydraulic retention time(HRT) of 2 hr which was 3 hr more short HRT than that(HRT 5 hr) reported in other related papers. This indicates that M-Dephanox process can reduce HRT of whole process.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.2
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• pp.90-103
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• 2014

Distribution characteristics of water masses, dissolved inorganic and organic nutrients were investigated in the southern part of the East Sea of Korea in September, 2011. On the basis of the vertical profiles of temperature, salinity and dissolved oxygen, water masses in the study area were divided into 4 major groups, such as WM (water mass)-I, WM-II, WM-III, WM-IV. Their characteristics were similar to Tsushima Surface Water (TSW), Tsushima Middle Water (TMW), North Korea Cold Water (NKCW) and East Sea Proper Water (ESPW), respectively. In the vertical profiles of dissolved nutrients, dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) concentrations were highest in the WM-IV, followed by WM-III, WM-II, WM-I. On the contrary, distribution of dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP) were highest in the WM-I, followed by WM-II, WM-III, WM-IV. Although the DIN : DIP ratio in all of the water masses was similar to Redfield ratio(16), the DIN : DIP ratio in mixed layer was about 5.3, indicating that inorganic nitrogen is the limiting factor for the growth of phytoplankton. However, the DON proportion in dissolved total nitrogen (DTN) was about 70% in the mixed layer where inorganic nitrogen is limiting factor. Thus, enriched DON may play an important source of the nutrient for the growth of phytoplankon in the East Sea.

• Journal of Soil and Groundwater Environment
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• v.8 no.3
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• pp.30-36
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• 2003

The effect of humic acid on the simultaneous removal of nitrate and phosphate was investigated in a micellar-enhanced ultrafiltration (MEUF). At the low molar ratio of cetylpyridinium chloride (CPC) to contaminants, the removal of nitrate was lower to 50％ by 100 ppm of humic acid due to the competition for binding on micelles. At the molar ratio higher than 3, however, the removal of nitrate was over 80％. Phosphate was removed over 80% at the molar ratio higher than 1. The CPC and humic acid were rejected over 99 ％ by UF membrane. The flux did not decrease by 100 ppm of humic acid but rather slightly increased since the humic acid adsorbed on the membrane made the membrane more hydrophilic. As a result, humic acid did not diminish the performance of MEUF in the simultaneous removal of nitrate and phosphate.

• Clean Technology
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• v.8 no.2
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• pp.77-83
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• 2002

The purpose of this study is to develop the efficient nutrient removal process and to verify operation and design parameters in domestic sewage. Endogenous nitrate respiration (ENR) was used for denitrification of nitrate in return sludge without additional organic carbon source. ENR reactor before the anaerobic tank enable to reduce nitrate below 3 mg/L and increase phosphate release at anaerobic reaction. Primary effluent during pilot scale plant were shown as TCOD/TP ratio of 40~60 and TCOD/TKN ratio of 5~7. Effluent concentrations were 10 to 12mg/L as TN and 1mg/L as TP respectively. In lab scale experiments endogenous denitrification rate of ENR reactor ranges from 0.042 to $0.057gNO_3-N/gMv.d.$ $SP_{rel}/SCOD_{rm}$ was shown as from 0.13 to 0.17 in anaerobic reaction. These kinetic parameters are expected to be available for BNR(Biological Nutrient Removal) plant design and ENR reaction is available for nutrient removal in low strength wastewater.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.20 no.4
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• pp.180-191
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• 2015

Marine environmental characteristics and primary productivity of phytoplankton were investigated in seaweed bed of northwestern coast of Jeju Island during Autumn, 2014. The trophic state based on dissolved inorganic nitrogen and phosphorus was mesotrophic. The Redfield ratio was less than 16, indicating that nitrogen was the limiting factor for the growth of phytoplankton. Dissolved organic nitrogen and phosphorus accounts for 63 and 46% of the dissolved total nitrogen and phosphorus, respectively. Light utilization efficiency (${\alpha}$) and maximum photosynthetic capacity ($P_m{^B}$) were highest in the Donggwi (third-year marine forest), followed by Gonae (one-year marine forest), Biyangdo (natural seaweed bed) and Geumneung (whitening area). The primary productivity of phytoplankton in the Donggwi, Gonae and Biyangdo also was higher than that in the Geumneung. Although nitrogen is the limiting factor, enriched dissolved organic nitrogen might play an important role to maintain primary productivity. In addition, phytoplankton community through photosynthesis could produce about 14% of phytoplankton carbon in one hour. These results will be able to use the important information for material cycle and ecological valuation of seaweed bed.