• 대한환경공학회지
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• 제31권8호
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• pp.649-654
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• 2009

산소소비속도 측정에 의한 미생물 호흡률 분석방법에 의해 하수의 유기물질과 미생물 분율을 평가하였다. 하수의 유기물과 미생물 분율은 생물학적 공정의 모델링을 위한 중요한 기초자료이다. 본 연구에서 하수의 유기물 분율을 측정한 결과, 미생물에 의해 분해가 빠른 유기물, 분해가 느린 유기물, 분해되지 않는 용존성 유기물, 분해되지 않는 고형 유기물과 종속영양미생물의 분율은 각각 26.6%, 41.5%, 8.5%, 14.7% 및 8.7%였다. 또한, 질소 분율을 측정한 결과, 질산성 질소, 암모니아성 질소, 용존성 비분해 유기성 질소, 용존성 분해 유기성 질소 및 분해가 느린 유기성 질소의 분율은 각각 약 3.7%, 64.9%, 4.7%, 9.4% 및 17.4%였다.

• 상하수도학회지
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• 제21권3호
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• pp.295-303
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• 2007

Nitrogen compounds in municipal wastewater can be divided into biodegradable and nonbiodegradable fractions with biodegradability. Biodegradable nitrogen compounds can be removed through biological nitrification and denitrification processes, and nonbiodegradable nitrogen compounds affect the effluent quality of biological nutrient removal processes. The amount of nitrifiable nitrogen compounds, which are the sum of ammonia and biodegradable organic nitrogen, has been estimated by respirometry. Respirometry shows good estimation of the concentration of nitrifiable nitrogen when a synthetic sample of ammonium chloride is dosed. The estimated concentration of nitrifiable nitrogen compounds in municipal wastewater is close to ammonia concentration in municipal wastewater, but it is lower than that for the synthetic sample. If nitrogen assimilated into cell synthesis of nitrifiers and heterotrophs is considered, the total amounts of nitrifiable nitrogen compounds, which are nitrified and assimilated, could be more accurately estimated. The concentration of nitrifiable nitrogen compounds, which are biodegradable, is about 31 mg N/l, and this is 119% of ammonia and 94% of total nitrogen. Ammonia, nitrate, biodegradable organic nitrogen, and nonbiodegradable nitrogen are about 79%, 1%, 15%, and 5% of the total nitrogen in municipal wastewater, respectively.

• 아시안잔디학회지
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• 제9권4호
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• pp.265-273
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• 1995

This investigation is carried out to clarify the cycles of nitrogen in the grassland ecosystems of Zoysia japonica and a Miscanthus sinensis on Mt. Kwanak. The hasic differential equation for the rate of change of nitrogen storage is illustrated hy huild-up and turnover of organic nitrogen, particularly in the ecosystems. The turnover velocity fractions of nitrogen for the Z. japonica and M .sinensis grasslands were k= 0. 181 and k=0. 166, respectively. The times required to reach 50, 95 and 99 percent of the steady state levels and turnover values of nitrogen on the grassland floors were 3.85, 16.67 and 27.78 years in the Z japonica grassland and 4.08, 17.65 and 29.41 years in the M sinensis grassland. The amount of annual cycles of nitrogen are 560.2 g /$m^2$ in the Z.japonica grassland and 654.1 g /$m^2$ in the M. sinensis grassland. Key words : Zsysia japonica Alisca nthus sinensis, Mt. Kivanak, Nitrogen cycle.

• Fisheries and Aquatic Sciences
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• 제13권2호
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• pp.133-139
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• 2010

The effects of suspended solids size on culture water quality were determined in a commercial recirculating aquaculture system (RAS) for Japanese eel, Anguilla japonica. The particulate phase of the culture water was serially divided into six size fractions using 300, 200, 100, 75, 45, and 26 ${\mu}m$ pore size stainless sieves. The total, dissolved, and particulate nitrogen and phosphorus, and suspended solids for each fraction were determined. The concentration ranges in the fractions were: total nitrogen, 164-148 mg $L^{-1}$; total phosphorus, 20.4-15.5 mg $L^{-1}$; and total suspended solids, 8.1-6.1 mg $L^{-1}$. The concentration of total nitrogen and total phosphorus decreased significantly (P<0.05) with a 26 ${\mu}m$ and 200 ${\mu}m$ filter pore size, respectively. Nutrients from dissolved organic substances were much higher than from particulates. Analysis of particle size fractionation and its effects on water quality is useful to estimate removal efficiencies of a commercial effluent screening device for solid management and development of solid removal systems.

• 대한환경공학회지
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• 제36권9호
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• pp.604-608
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• 2014

천연유기물질(NOM)과 모노클로라민이 반응할 때 NOM내 용존유기질소(DON)가 유기성 클로라민의 생성에 미치는 영향에 대하여 조사하였다. 실험에 사용된 16가지 NOM의 용존유기탄소(DOC)에 대한 DON의 비(DOC/DON)는 7~47 mg-C/mg-N이었다. NOM 용액의 모노클로라민 반응시 유기성 클로라민 생성 농도는 24시간 후에 최대치(평균값 $0.16mg-Cl_2/mg-N$)로 염소반응에 비하여 유기성 클로라민의 생성량은 적었으나, 분해되어 감소되는 속도는 낮아 반응 120시간 후에 최대치 대비 평균 56% 감소되었다. NOM내 DON의 함유비가 높은 경우(DOC/DON 비가 낮은 경우)에 유기성 클로라민의 생성량이 상대적으로 높게 나타났으나, 소수성, 친수성, 중간성, 콜로이드성 등 NOM의 특성에 따른 유기성 클로라민 생성량의 차이는 크지 않았다. 모노클로라민의 주입량을 증가시킬수록 유기성 클로라민 생성량이 선형적으로 증가하였고($R^2=0.91$), 주입된 모노클로라민 중 6%가 유기성 클로라민으로 전환되어 모노클로라민 소독시 유기성 클로라민 형성에 의한 소독능 저하는 크게 우려할 바는 아닐 수 있다.

• 한국해양환경ㆍ에너지학회지
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• 제19권2호
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• pp.144-150
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• 2016

동해 남서해역에서 입자성 유기탄소와 질소의 시 공간적인 분포 특성을 파악하기 위해서 2011년 9월(하계), 2012년 1월(동계) 그리고 5월(춘계)에 조사하였다. 9월 표층수는 용승 현상에 따른 냉수괴가 관찰되지 않았지만, 높은 chlorophyll a(Chl-a) 농도, 낮은 비광합성 유기입자물질 비율(27%) 그리고 낮은 POC/PON 비(6.2)로 활발한 아미노산 및 단백질 합성을 의미하는 높은 기초생산을 보였다. 하지만, 2012년 5월에는 높은 비광합성 유기입자물질(66%)과 높은 POC/PON 비(8.1)에 근거할 때, 9월과 비교하여 상대적으로 낮은 생산성을 보였다. 이와 같이 식물플랑크톤의 대량 발생이 주로 춘계에 발생한다는 기존의 결과와 상반되며, 이는 춘계 대발생 후기의 동물플랑크톤에 의한 페오피그먼트(phaeopigment)의 증가 때문으로 해석된다. 따라서 입자성 유기물질의 조성은 같은 계절이라도 해양환경의 변화에 따라 달라질 것으로 보인다.

• 한국자원식물학회지
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• 제21권6호
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• pp.435-439
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• 2008

Due to the fact that tocopherols and tocotrienols have antioxidant and anticancer properties, the commercial utilization of unsaponifiable fractions in rice bran is increasing. These nutraceutical compounds, however, are fairly unstable and readily break down when exposed to oxygen or lighting conditions. To compare the relative sensitivity of vit E isomers to heat and oxygen, concentrated unsaponifiable fractions extracted from crude rice bran oil were exposed to various temperature, oxygen (nitrogen-balanced), and bathing solvent conditions and resultant concentration changes in ${\alpha}$- and ${\gamma}$-tocopherols (T) and tocotrienols (T3) were evaluated. Each isomer exhibited different heat stability. Among them, ${\alpha}$-T3 degraded more rapidly compared to other vit E isomers while ${\alpha}$-T was the most stable isomer. Oxygen level also showed significant impact on each isomer's stability where severe reductions of ${\gamma}$-T (by 20%) and ${\gamma}$-T3 (by 29%) were observed under 2% oxygen conditions, while under 0% oxygen conditions no degradation could be observed even after exposure to $95^{\circ}C$ for 4 hours. When various blending solvents were mixed with concentrated unsaponifiable fractions, organic solvents such as isooctane and hexane were more effective in maintaining the stability of ${\gamma}$- T3 compared to edible oils, among which com oil was more efficient than soybean and rice bran oils.

• Journal of Korean Society for Atmospheric Environment
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• 제14권E호
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• pp.27-40
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• 1998

The solubility characteristics of organic compounds were studied in terms of the extraction efficiency as a function of the polarity of the organic solvent, and the acidity of water in urban aerosol samples collected in University of East Anglia (UEA), Norwich, England. The extraction efficiency of organic compounds were evaluated with respect to the organic carbon, -nitrogen and -hydrogen by means of a wide range of solvent which include polar and nonpolar organic solvents as well as acids and alkaline water. In addition, after being dissolved in aqueous solution, the aqueous chemistry of organic compounds were studied in terms of the organic metal complexes in aerosol, which were studied with oxalic acid, copper, and zinc. The results of this study indicate that solubility characteristics of organic compounds depend on the polarity of the solvents and the acidity of the solvents. In particular, some organic compounds are water soluble, even though they are much smaller than acetone soluble fractions. In the comparison between polar organic solvent extraction and non- polar organic solvent extraction, it can be thought that significant fraction of organic compounds analysed in the aerosol samples, are polar organic compounds because of the higher extraction efficiencies of organic compounds in polar organic solvent extraction than in nonpolar organic solvent extraction. Regarding the study of the oxalic -metal complexes, it can be thought that most oxalic acids are present in the form of oxalic -copper complexes in the aerosols collected at UEA.

• 한국물환경학회지
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• 제38권1호
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• pp.31-42
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• 2022

Dissolved organic matter (DOM), which changes according to various factors, is ubiquitously present from natural environments to engineered treatment systems. Only limited information is available regarding the environmental functions of DOM after bulk analyses are only applied for characterization. In this paper, latest DOM analytical techniques are briefly introduced, which include fluorescence excitation-emission matrix with parallel factor analysis (EEM-PARAFAC), size-exclusion chromatography with an organic carbon detector (SEC-OCD), carbon/nitrogen stable-isotope ratio, and Fourier transform-ion cyclotron resonance-mass spectroscopy (FT-ICR-MS). Recent examples of using advanced analyses to interpret the phenomena associated with DOM occurring in natural and engineered systems are presented here. Through EEM-PARAFAC, different components like protein-like, fulvic-like, and humic-like can be identified and tracked individually through the investigated systems. SEC-OCD allows researchers to quantify different size fractions. FT-ICR-MS provides thousands of molecular formulas present in bulk DOM samples. Lastly, carbon/nitrogen stable-isotope ratio offers reasonable tools for tracking the sources in environments. We also discuss the advantages and weakness of the above-mentioned characterizing tools. Specifically, they focus on single environmental factors (different sourced-DOM and interaction of sediment-pore water) or simple changes after individual treatment processes. Through collaboration with the advanced techniques later, they help the researchers to better understand environmental behaviors in aquatic systems and serve as essential tools for addressing various pending problems associated with DOM.

• Applied Biological Chemistry
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• 제30권2호
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• pp.169-178
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• 1987

Kluyveromyces marxianus로 부터 inulase를 생산하고 정제하며 intra 및 extracellular inulase의 성질을 조사하였다. 본 균주는 stationary phase인 24시간째 intra 및 extracelullar enzyme의 생산이 최고에 달했으며 유기 질소원으로 YNB를 사용하고 배양 중 pH를 조절해 줌으로써 효소 생산을 향상시킬 수 있었다. 조효소는 DEAE-cellulose에 의해 intra 및 extracellular inulase 모두 2개의 fraction으로 분리되었고 각 fraction의 전기영동 양상은 비슷하여 주 band를 비롯 모두 3개의 glycoprotein band가 관찰되었으며 이중 주 band만 inulase 및 invertase activity를 보유하고 있었다. 정제 효소의 inulase 및 invertase의 최적 pH는 각각 5.0과 4.5였고 intra가 extracellular enzyme 에 비해 다소 넓은 범위의 pH에서 높은 활성을 나타내었다. 모든 fraction의 최적 온도는 inulase가 $40^{\circ}C$, invertase가 $50^{\circ}C$였으며 intracellular enzyme이 더 넓은 범위의 온도에서 안정하였고 열에 대한 안정성도 intracellular inulase가 extracellular inulase보다 높게 나타났다. Km value는 intra가 $16{\sim}19mM$, extracellular inulase가 $9{\sim}11mM$로써 extracellular inulase가 inulin에 대한 친화력이 더 높았으나 모두 exo-type의 inulase로 판명되었다.