• 한국물환경학회지
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• 제23권4호
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• pp.482-489
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• 2007

Fluorescence properties and carbohydrate content were investigated using ultrafiltrated size fractions of dissolved organic matters (DOM) originated from different sources. The materials included a treated sewage, an algal organic matter, and a soil leachate, all of which are major constituents of dissolved organic matter in a typical urban river. Four different size fractions were separated from the three sources of each DOM. The size distribution demonstrated that a higher molecular weight fraction was more present in soil leachate compared to two other source DOMs. A higher content of carbohydrates was observed in the following order - algal DOM > treated sewage > soil leachate. A wide range of specific UV absorbance was observed from size fractions of a single source DOM, indicating that aromatic carbon structures are heterogeneously distributed within one source of DOM. The structural heterogeneity was the most pronounced for the soil leachate. The fluorescence index ($F_{450}/F_{500}$) of the treated sewage was similar to that (2.0) typically obtained from autochthonous DOM, suggesting that the treated sewage exhibited autochthonous organic matter-like properties. No protein-like fluorescence intensities were observed for all of the soil leachate size fractions whereas they were observed with two other source DOMs. Based upon the fluorescence peak ratios from fluorescence excitation-emission matrix (EEM), two discrimination indices could be suggested to distinguish three different source DOMs. It is expected that the suggested discrimination indices will be useful to predict the sources of DOM in a typical urban river affected by treated sewage.

• 상하수도학회지
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• 제22권1호
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• pp.31-38
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• 2008

The primary objective of this study was to evaluate the variation of the molecular size distribution by granular activated carbon (GAC) adsorption. GAC adsorption was assessed by using the rapid small-scale column test (RSSCT) and high-performance size-exclusion chromatography (HPSEC) was used to analyze the molecular size distribution (MSD) in the effluent of GAC column. RSSCT study suggested that GAC adsorption exhibited excellent interrelationship between dissolved organic carbon (DOC) breakthrough and MSD as function of bed volumes passed. After GAC treatment, the nonadsorbable fraction which was about 25percents of influent DOC corresponded to the hydrophilic (HPI) natural organic carbon (NOM) of NOM fractions and was composed entirely of <300 molecular weight (MW) in the HPSEC at the initial stage of the RSSCT operation. The dominant MW fraction in the source water was 1,000~5,000daltons. At the bed volumes 2,500, MW <500 of GAC treated water was risen rather than it of source water. After the bed volumes 7,300 of operation, the MW 1,000~3,000 fraction was closed to about 80percents of DOC found in the GAC influent. The Number-average molecular weight (Mn) value determined using HPSEC for the effluent of GAC column was gently increased as DOC breakthrough progress. The quotient p(Mw/Mn) can be used to estimate the degree of polydispersity was shown greatest value for the GAC effluent at the initial stage of the RSSCT operation.

• 미생물학회지
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• 제35권1호
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• pp.35-40
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• 1999

소양호에서 식물 플랑크톤이 분비하는 유기물의 분자량 크이게 따른 세균수와 활성의 변화를 측정하였다. 소양호 상걸리 유역에서 여름철에 채수한 물을 tangential flow ultrafiltration 으로 용존 유기물질을 100,000 nMW~0.1$\mu\textrm{m}$, 10,000 nMW~100,000 nMW와 1,000 nMW~10000 nMW의 3개 fraction으로 구분하였고, 여기에 호숫물을 접종하여, 세균수와 $\beta$-glucosidase 의 변화를 측정하였다. 배양기간 동안에 나타난 총세균수는 24시간까지 급격히 증가한 후 점차 안정적으로 변하는 전형적인 성장곡선을 나타내었으며, DOC 농도와 종류가 달랐음에도 , $1.2{\times}10^{7}$ cells $ml^(-1)$범위였고, 저분자 fraction에 비해 최고 1,000배 이상 높았다. 즉 10,000 nMW 이상의 고분자 용존 유기물질은 $\beta$-glucosidase의 유도체로 작용하며, 저분자 용존 유기물질은 $\beta$-glucosidase 활성도를 높이지 못하는 것으로 확인되었다.

• 한국물환경학회지
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• 제37권6호
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• pp.458-468
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• 2021

In this study, we investigated the variations of dissolved organic matter (DOM) in an agricultural reservoir during the monsoon period (June to October, 2020) with respect to the organic carbon concentration (DOC), molecular weight distribution, and optical properties. The monsoon period was divided into three phases - beginning storm (BS), during storm (DS), and after storm (AS). Our results showed significant differences in the concentrations and characteristics of DOM during the summer monsoon. The DOC concentrations were decreased after the monsoon, probably due to a dilution effect. In contrast, increasing trends were observed in the specific UV absorbance (SUVA), and relative abundances of humic-like fluorescence and larger-sized compounds. These observations implied that the large-sized and humic-like organic components with terrestrial origins strongly affected the reservoir DOM after the summer monsoon. Meanwhile, biopolymer size fraction, which is associated with algal activity, became more abundant after the monsoon. These results suggest that DOM with autochthonous sources became dominant as a result of the inflow of nutrients into the reservoir after the storm. Spatial changes in DOM within the reservoir were not pronounced as much as the temporal variations. All taken, it can be concluded that the summer monsoon simply led to the decrease of DOM concentrations while the sources and the quality of DOM underwent substantial changes, which may enrich refractory organic matter in the reservoir. This study reveals the importance of in-depth DOM quality monitoring before and after summer monsoon for effective water quality management in agricultural reservoirs.

• Environmental Engineering Research
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• 제23권4호
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• pp.390-396
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• 2018

This study investigated the transformation of dissolved organic matter (DOM) in a free-water surface flow constructed wetland. Pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) coupled with preparative high-performance liquid chromatography (prep-HPLC) was used to analyze the compositions of biopolymers (polysaccharides, amino sugars, proteins, polyhydroxy aromatics, lipids and lignin) in DOM according to the molecular size at three sampling points of the water flow: inflow, midflow, and outflow. The prep-HPLC results verified the decomposition of DOM through the decrease in the number of peaks from three to one in the chromatograms of the sampling points. The Py-GC/MS results for the degradable peaks indicated that biopolymers relating to polysaccharides and proteins gradually biodegraded with the water flow. On the other hand, the recalcitrant organic fraction (the remaining peak) in the outflow showed a relatively high concentration of aromatic compounds. Therefore, the ecological processes in the constructed wetland caused DOM to become more aromatic and homogeneous. This indicated that the constructed wetland can be an effective buffer area for releasing biochemically stable DOM, which has less influence on biological water quality indicators, e.g., biochemical oxygen demand, into an aquatic ecosystem.

• Membrane and Water Treatment
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• 제13권1호
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• pp.29-37
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• 2022

To verify the fate and transport of engineered nanoparticles (ENP), it is essential to understand its interactions with organic matter. Previous research has shown that dissolved organic matter (DOM) can increase particle stability through steric repulsion. However, the majority of the research has been focused on model organic matter such as humic or fulvic acids, lacking the understanding of organic matter found in field conditions. In the current study, organic matter was sampled from wastewater treatment plants to verify the stability of engineered nanoparticles (ENP) under field conditions. To understand how different types of organic matter may affect the fate of ENP, wastewater was sampled and separated based on their size; as small organic particular matter (SOPM) and large organic particular matter (LOPM), and dissolved organic matter (DOM). Each size fraction of organic matter was tested to verify their effects on nano-zinc oxide (nZnO) and nano-titanium oxide (nTiO₂) stability. For DOM, critical coagulation concentration (CCC) experiments were conducted, while sorption experiments were conducted for organic particulates. Results showed that under field conditions, the surface charge of the particles did not influence the stability. On the contrary, surface charge of the particles influenced the amount of sorption onto particulate forms of organic matter. Results of the current research show how the size of organic matter influences the fate and transport of different ENPs under field conditions.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1998년도 한국생물과학협회 학술발표대회
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• pp.182.2-182
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• 1998

No Abstract, See Full Text

• 대한환경공학회지
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• 제35권11호
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• pp.769-775
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• 2013

본 연구에서는 두 가지 기원의 표준 휴믹물질 혼합 시료와 Suwannee River fulvic acid (SRFA)을 사용하여 광분해로 인한 용존 유기물질의 스펙트럼 특성 변화와 이에 따른 소독 부산물 생성능의 변화를 조사하였다. 혼합시료의 염소소독부산물 발생잠재력(DBPFP)은 specific UV absorbance (SUVA) 값에 비례하여 증가하였다. 7일간 광분해 후 혼합시료의 SUVA 값은 모두 감소하였다. 그러나 동일 시료에서 DBPFP 값은 SUVA 감소폭보다 적었다. 비록 두 변수 사이에 직선성은 유지되었으나 같은 SUVA 범위 내에서의 DBPFP 값은 오히려 감소하는 경향을 보였다. 이 결과는 광분해로 인해 염소소독부산물 전구체 역할을 하는 비방향족 물질이 생성될 수 있음을 시사하였다. SRFA 시료에 대해 4일과 13일 광분해하여 각각 저분자와 고분자 부분에서의 DBPFP 값을 비교한 결과 광분해 후 유기탄소 당 염소소독부산물 발생량 변화양상은 염소소독부산물 종류에 따라 다르게 나타났다. 유기탄소 당 trihalomethenes (THMs) 발생은 광분해 후 고분자 부분에서 더 높았으나 haloacetic acids(HAAs)의 경우 고분자와 저분자 부분 사이의 유의한 차이가 관찰되지 않았다. 광분해 시간에 따른 유기탄소 당 DBPFP 값 변화 패턴도 용존 유기물 분자량에 따라 다르게 나타났다. THMs의 경우 고분자 부분에서는 광분해 시간에 따라 증가하는 경향을 보였으나 저분자에서는 큰 변화를 보이지 않았다. 반면 HAAs은 고분자에서 지속적인 감소 경향을, 저분자 부분에서는 증가 후 다시 감소하는 경향을 보였다. 본 연구결과 수중 유기물질은 전반적으로 광분해에 따라 소독부산물 생성능이 초기에 오히려 증가할 수 있으며 광분해 시간이 충분히 지속된 후에야 감소함을 보여주었다.