• 지질공학
• /
• 제23권4호
• /
• pp.427-434
• /
• 2013

구제역 매몰지에서 발생하는 침출수는 지하수, 호소수 및 하천수 등의 자연수에서 나타나는 유기물질의 성상(친수성 유기물질: 22~27%)과 달리 친수성유기물질을 44~50%로 포함하고 있었다. 자연수에서는 유기탄소가 미생물의 대사 등에 의해 감소되는 경향을 나타낸다. 하지만, 매몰 초기에 발생하는 구제역 침출수(leachate-1, 2)에서는 RTOC와 RDOC의 농도가 초기 TOC, DOC 농도보다 높게 나타나는 특성이 있다. 매몰시간이 경과하면서 RTOC와 RDOC는 초기 TOC와 DOC보다 낮게 검출되었다. 구제역 침출수 중 386일이 경과한 leachate-6의 RDOC는 RTOC 중에 91%를 차지하였다. 이것은 안정화된 매몰지 환경에서도 침출수 중에는 여전히 미생물 등의 활동에 의해 제거되기 어려운 형태의 난분해성 유기물질이 유기물질의 대부분을 차지하고 있음을 알 수 있다. 따라서 구제역 침출수의 난분해성 유기물질의 검출수준과 성상은 지표수 및 지하수에 대한 영향을 파악하는 정보로서 유효하며, 침출수 내 환경을 이해하는 데에도 기여할 것으로 기대된다.

• 환경위생공학
• /
• 제12권3호
• /
• pp.31-39
• /
• 1997

The seasonal and spatial changes in dissolved organic carbon(DOC) in Lake Kasumigaura, a shallow and eutrophic lake, were analyzed from October 1992 to October 1995. The proportion of T-DOC was classified by labile(L-DOC) and refractory DOC(R-DOC) on the basis of long-term incubation, fractionated the molecular weight of T-DOC by ultrafiltration. The porewater DOC were measured at sedimental surface of the central basin in order to evaluate the DOC released from the sediment. The proportion of L-DOC and R-DOC were accounted for about 15% and 85% of T-DOC in the central basin, respectively. The molecular weight(MW) distribution occupied some 60% of the low and medium MW. The horizontal variation of T-DOC concentrations trended to higher in the central basin than in the inlet of influent rivers, because of contribution by autochthonous organic carbon loading. The seasonal variation of T-DOC showed to higher summer than winter in the inlet of influent, but at the central basin it fluctuated little seasonally. During the high increase of porewater DOC in 1994 evaluated the high release possibility from the sediment surface (10cm). The present study suggests that autochthonous organic carbon loading must be controlled for improving the water quality of the eutrophic lakes.

• Ocean and Polar Research
• /
• 제43권2호
• /
• pp.65-72
• /
• 2021

In order to evaluate the dissolved organic carbon (DOC) and fluorescent dissolved organic matter (FDOM), as indicators of organic matter in the coastal environments, we measured the concentrations of DOC, FDOM, and chemical oxygen demand (COD) in saline groundwater (Woljeong, Pyoseon, and Hwasun beaches) and coastal seawater (Haengwon, Gwideok, Pyoseon, and Yeongnak) in Jeju, Korea. The highest concentrations of DOC and COD in groundwater were found in Woljeong and Pyoseon, and those in coastal water were observed in Haengwon and Pyoseon, indicating that the higher concentrations of DOC and COD seem to be associated with saline groundwater-driven dissolved organic matter (DOM) and/or biogeochemical processes. According to origin and optical properties of DOM using FDOM as a tracer, proportion of humic-like FDOM, more refractory DOM, was relatively greater in the groundwater than in the coastal water. With regard to this result, there was no relationship between DOC and COD in groundwater, while DOC showed a good positive correlation (r² = 0.66) with COD in coastal water. This result indicates that COD as an indicator of assessment of DOM has a limitation in which it is difficult to quantify refractory DOM. Although DOC is a potential alternative to COD in the coastal environments, particulate organic carbon cannot be negligible due to relatively higher concentration compared to the open ocean. Therefore, the use of total organic carbon (TOC) as a replacement of COD in the coastal ocean is important, and the evaluation criterion of the TOC is necessary in order to evaluate of organic matter indicator in the various coastal environments.

• 산업기술연구
• /
• 제26권A호
• /
• pp.199-205
• /
• 2006

Ozone alone and catalytic ozone processes were introduced for treatment of humic acid, which is representative refractory organic compound. The treatment efficiencies of humic acid in each process were analyzed in pH variation, DOC removal, and $UV_{254}$ decrease. Mn loaded GAC catalyst was prepared by loading potassium permanganate onto the granular activated carbon surface. BCM-GAC and BCM-Silica gel catalyst were prepared by BCM. $UV_{254}$ decrease in all processes was comparatively high with efficiency over 87%. DOC removal in ozone/GAC process was the highest with 78%, and removal rates for other processes followed the order ozone/BCM-GAC(62%) > ozone/BCM-silica gel(45%) > ozone/silica gel(43%) > ozone/Mn Loaded GAC(42%) > ozone alone(37%).

• 한국물환경학회지
• /
• 제21권2호
• /
• pp.125-131
• /
• 2005

Natural organic matter(NOM) is defined as the complex matrix of organic material and abundant in natural waters. It affects the performance of unit operations for water purification. Several kinds of analytical indicators such as DOC, specific ultraviolet absorbance(SUVA), apparent molecular weight (AMW), fractionation and high performance size exclusive chromatography(HPSEC) have been used to understand characteristics and variations of NOM. This study aims to evaluate the characteristics of NOM in the Geum River system comprising with stream flows and reservoirs. It was identified that SUVA denoting the portion of humic substance in water ranged within 1.60~3.36. Using resin adsorbents, dissolved organic carbon(DOC) was fractionated into three classes: hydrophobic bases(HOB), hydrophobic acids(HOA) and hydrophilic substances(HI). HI dominates in all samples, collectively accounting for more than 62% of the DOC. HOA was the second dominated fraction and it varied considerably but accounted for about 30% of the DOC. The distribution of high molecular weight(HMW) measured by HPSEC being used to determine the molecular weight distribution of aquatic humic substances was 40.1% and 38.7% in reservoir and stream flow, respectively. The distribution of low molecular weight(LMW) in stream flow was 13.2% higher than that in reservoir. And apparent molecular weight less than 1KDa, which include the molecular weight of hydrophilic organic matter, occupied with 69.2% and 68.2% in stream flow and reservoir, respectively. While the molecular weight of 1 to 100 KDa including humic substances ranged with 18.6% and 21.6% in stream flow and reservoir, respectively. Seasonal variation of refractory dissolved organic carbon was similar to that of SUVA.

• Membrane and Water Treatment
• /
• 제15권3호
• /
• pp.99-106
• /
• 2024

This study developed an efficient management plan to improve the water quality by analyzing fluctuations in the ratio and amount of various organic substances in streams considering watershed characteristics and rainfall patterns. Monitoring was conducted on three streams and one lake over seven sessions during wet and dry seasons. Water quality indicators including total organic (TOC), refractory dissolved organic (RDOC), and particulate organic (POC) carbons were analyzed using high-temperature combustion oxidation. The three streams (Cheongmi, Yanghwa, and Bokha) displayed high TOC concentrations during the rainy season because the accumulated organic substances from the dry season were washed away by rainfall. By contrast, Paldang Lake exhibited a substantial decrease in TOC concentration due to dilution, which was influenced by watershed and rainfall characteristics. Across all streams and lakes, dissolved organic carbon (DOC) accounted for the highest proportion, at 77.5% of TOC, with RDOC making up 91% of DOC and 71% of TOC. Although POC contributed a small annual proportion to annual TOC, the concentration rapidly increased during late spring and early summer, with increases of 40.403%, 25.99%, and 27.388% in Cheongmi, Yanghwa, and Bokha, respectively. Continuous monitoring of RDOC is essential to identify seasonal fluctuations and changes due to rainfall events. Furthermore, intensive POC management during the rainy season, particularly in May and June, is potentially economical and efficient for water quality management.

• 한국물환경학회지
• /
• 제39권2호
• /
• pp.131-141
• /
• 2023

In this study, the relationship between organic carbon distribution characteristics and decomposition rate classified according to the particle size and biological degradation characteristics in water was investigated for the Nam river and Geumho river. The average concentrations of TOC in the Nam river and Geumho river were 2.7±1.2 mg/L and 5.0±1.2 mg/L, respectively, but the composition ratios for each type of organic carbon were similar. An average value of 80.9% of TOC was present as DOC and 72.8% of DOC consisted of Refractory-DOC (RDOC). In addition, the change in the RDOC composition ratio according to temporal and spatial distribution was the smallest. There was no difference in the decomposition rate of organic carbon except for TOC by the site (p≥0.108, one-way ANOVA), and the decomposition rates of Labile-POC (LPOC) and LDOC were similar at 0.139±0.102 and 0.137±0.149 day^-1, respectively (p=0.110, paired t-test). The coefficient of variation (CV) of the decomposition rate of DOC (average 8.1%), which had the smallest composition ratio of organic carbon, was 1.1, showing the largest temporal variation. The TOC, POC, and DOC decomposition rates showed a significant correlation with the ratio of the initial concentration to the concentration after 25 days of decomposition (OC₂₅/OC₀) (r²=0.89~0.94, p<0.001), and the decomposition rates of LPOC and LDOC were significantly correlated with the ratio of the initial concentration to the concentration after 5 days of decomposition (LOC₅/LOC₀) (r²=0.67~0.75). This suggests that it is possible to estimate the decomposition rate through the concentration of each type of organic carbon.

• 산업기술연구
• /
• 제28권A호
• /
• pp.23-26
• /
• 2008

Ozone/GAC and ozone-GAC processes were introduced for treatment of humic acid, which is representative refractory organic compound. The treatment efficiencies of humic acid in each process were analyzed in pH variation, DOC removal, and $UV_{254}$ decrease. $UV_{254}$ decrease in all processes was comparatively high with efficiency over 92%. $UV_{254}$ decrease in ozone alone process was 85%. DOC removal in Ozone-GAC process was the highest with 75%. Removal by Ozone/GAC, Ozone alone processes were 71% and 33% respectively.

• 산업기술연구
• /
• 제27권A호
• /
• pp.25-29
• /
• 2007

Ozone alone, Ozone/GAC, Ozone/$H_2O_2$ and Ozone/GAC/$H_2O_2$ processes were introduced for treatment of humic acid, which is a representative refractory organic compound. $H_2O_2$ and GAC used as catalysts for experiment. The treatment efficiencies of humic acid in each process were analyzed for pH variation, DOC removal, and $UV_{254}$ decrease. $UV_{254}$ decrease in Ozone/GAC and Ozone/GAC/$H_2O_2$ processes were the highest with about 93%, and Ozone alone and Ozone/$H_2O_2$ processes were 88%. DOC removal in Ozone/GAC/$H_2O_2$ process was the highest with 71%. Removal by Ozone/GAC, Ozone alone, and Ozone/$H_2O_2$ processes were 66%, 39%, and 47%, respectively.

• Ocean and Polar Research
• /
• 제39권1호
• /
• pp.35-43
• /
• 2017

Concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), dissolved organic phosphate (DOP), and colored dissolved organic matter (CDOM) were measured in the coastal sea off inland aqua farms in northeastern Jeju Island in summer 2015. The highest concentrations of DOC, DON, and DOP were revealed in the surface water off Hado-ri where the lowest salinity conditions prevailed (31.6). The concentrations of DOC, DON, and DOP in the surface water were lower in the inner stations (SH1-1, 1-2, and 1-3) near the aqua farms of the Haengwon-ri than in the outer stations. The concentrations of DOC, DON, and DOP negatively correlated with salinity. These results indicate that the contribution of dissolved organic matter (DOM) from the aqua farms seems to be not significant. On the other hand, the higher concentrations of DON and DOP in the inner stations of Hado-ri (HD 1-1) seem to be attributed to excrement of migrating birds. The three components of CDOM (T, M, and C peaks) showed no relationship with salinity, perhaps due to various in situ productions by marine organisms and decomposition by ultraviolet radiation. The observed lower C:M ratio, an indicator of terrestrial source, and the higher biological index (BIX) of CDOM in the station off Hado-ri indicate that DOM is produced mainly by biological activity. Based on the higher humification index (HIX) of CDOM and the higher DOC:DON ratio off Haengwon-ri, refractory DOM in the inland aqua farms is likely transported to the coastal sea.