• Journal of Korean Society on Water Environment
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• v.25 no.3
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• pp.419-424
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• 2009

Characteristics of humic substances on the changes in dissolved organic matter (DOM) characteristics by biodegradation was investigated using three types of the artificial water samples composed of glucose and Suwannee River fulvic acid (SRFA). Some selected DOM characteristics including the specific UV absorbance (SUVA), the synchronous fluorescence spectra and the molecular weight (MW) were compared for the artificial water samples before and after 28-day microbial incubation. The changes of the DOM characteristics were minimal for SRFA during the incubation whereas they were significant for glucose. SUVA, dissolved organic carbon (DOC)-normalized fluorescence intensity, and MW values of glucose increased, suggesting that such labile organic compounds could be exclusively transformed into more humidified materials by biodegradation. For glucose-SRFA mixture, the selected DOM characteristics were greater than those estimated using the assumption that the individual changes of either glucose or SRFA are conservative for the mixture of the two materials. Our results suggest that the presence of humic substances (HS) may lead to the enhancement of the formation of refractory organic materials during biodegradation of labile compounds. Detailed analyses of size exclusion chromatography (SEC) revealed that the enhancement occurred for the DOM mixture with a MW range between 500 Da to 4000 Da.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.997-1002
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• 2007

The objectives of this research are to remove dissolved organic matter and nitrogen compounds by using aerated submerged bio-film(ASBF) reactors in batch systems and improve understanding of dissolved organic matter and nitrogen compounds removal rates with dynamic relationships between heterotrophic and autotrophic bacteria in the fixed-film reactor. This research explores the possibility of enhancing the performance of shallow wastewater treatment lagoons through the addition of specially designed structures. These structures are designed to encourage the growth of a nitrifying bacterial bio-film on a submerged surface. Specially, the effects of cold temperatures on the dissolved organic matter and ammonia nitrogen performance of the ASBF pilot plant was investigated for the batch system. It is anticipated thai the ASBF would be used for a design of biological treatment for removing of dissolved organic matter and nitrogen compounds in new wastewater treatment plants as well as existing wastewater treatment plants.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.233-240
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• 2016

Control degree and property changes of dissolved organic matter (DOM) were conducted by coagulation of chemical treatment for 2 sewage treatment plants with different technical methods. As the result, SUVA value of the second treated water (supernatant of the second settling pond after biological treatment) was increased and DOC was reduced in comparison with supplied raw water. And, SUVA value and DOC were reduced by coagulation after coagulation treatment of the second treated water. Properties of dissolved organic matter for 2 sewage treatment plants's DOC were divided. As the result, there was lots of hydrophilic component with hydrophilicity in case of plant A. In case of the second treated water, Plant A showed fulvic acid with little molecular weight was reduced among the hydrophobic component with hydrophobicity, but numic acide with lots of molecular weight was increased. However, in case of plant B, both fulvic acid with little molecular weight and humic acid with lots of molecular weight were increased among the hydrophobic components with hydrophilicity. Before the operation of phosphorus facility, properties of dissolved organic matter after biodegradation with effluent water showed hydrophilic components were reduced and hydrophobic components were increased. However, after coagulation treatment of the second treated water, hydrophilic components and hydrophobic components were outstandingly decreased or increased. During the biodegradation after coagulation treatment, hydrophilic components were significantly decreased and hydrophobic components were increased.

• Journal of Korean Society on Water Environment
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• v.37 no.6
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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.

• Journal of Korean Society on Water Environment
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• v.30 no.6
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• pp.605-611
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• 2014

This research was carried out to examine the concentration and fate of dissolved organic matter due to the increased detention time in middle and down stream of the Nakdong River. Aldo the characteristics of biodegradation of DOM were investigated according to the various water sources. The approaches used to characterize DOM biodegradability include the changes in DOC concentration and DOM fraction. Long-term biodegradation test for each organic source was also conducted. As the result, maximum 50% of DOC was reduced during the first 30 days of biodegradation tests. After 30 days, biodegradation of organic matter was continuously progressed, as showing continuous reduction of DOC. While DOC concentration was reduced, SUVA values for the organic matters were increased. Properties of dissolved organic matter by water sources also showed decreasing hydrophilic components while showing increased hydrophobic components. The more rapid reduction of the hydrophilic components than hydrophobic components might be due to the preferential degradation of the hydrophilic components by microorganisms during biodegradation process.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.246-249
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• 2002

Black shale that has relatively high organic carbon content was tested to determine its sorption phenomena and capacity for TCE. Conventional batch sorption tests were peformed at room temperature. The parameters that were thought to affect the TCE sorption were solution pH and dissolved organic matter. The effect of solution pH on TCE sorption was minimal, but the dissolved organic matter increased the amount of TCE sorbed on black shale. Thus, using black shale as sorbent for TCE in groundwater could save material costs by replacing high cost conventional activated organic carbon.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.3
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• pp.189-201
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• 2012

Radiocarbon is a powerful tool for studies of carbon cycling in the ocean. Development of measurement technology of accelerator mass spectrometry has enabled researchers to measure radiocarbon even in specific compounds. In this paper, a brief introduction on radiocarbon measurement and reporting of radiocarbon data is provided. Researches that used radiocarbon measurements on bulk organic matter, organic compound classes, and specific organic compounds are reviewed. Examples include works to understand the cycling of particulate and dissolved organic matter, biochemical composition of particulate organic matter, post-depositional transport of sedimentary organic matter, selective incorporation of fresh organic matter by benthic organisms, chemoautotrophy by archaea, and sources of halogenated chemical compounds found in marine mammals.

• Korean Journal of Environmental Agriculture
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• v.20 no.5
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• pp.346-351
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• 2001

Oxidation of Cr(III) to Cr(VI) can increase availability and toxicity of chromium. In this study, possible mechanisms by which pH and organic matter can control the chromium oxidation and reduction in soil system were examined using four soils of different pHs and organic matter contents. Reduction of Mn-oxides occurred in the soils of higher organic matter content (4.0%), but Mn-oxide was quite stable during the incubation in the soil of pH 7.0 and 0.5% organic matter content. Manganese oxides can be reductively dissolved at lower pH and higher organic matter conditions. The soil of pH 7.0 and 4.0% organic matter content showed the highest Cr-oxidation potential. Reduction of soluble Cr(VI) was observed in all the soils examined. The most rapid reduction was found in soil of pH 5.5 and 4.0% organic matter content, but the reduction was slow in soil of pH 7.0 and 0.5% organic matter content. Thus, the reductive capacity of organic matter added soils was much higher as compared to other two soils of lower organic matter content. In all the soils examined, the reductive capacity of soluble chromium was much higher than the oxidative capacity. Organic matter was found to be the most important controlling factor in the chromium oxidation and reduction. Reduction of Cr(VI) to Cr(III) could be a potentially useful remediation or detoxification process, and availability and toxicity of chromium in soil would be controlled by controlling organic matter content and pH of the soils.

• Journal of Korean Society on Water Environment
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• v.28 no.2
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• pp.238-246
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• 2012

Organic matters budget in Lake Hoengseong were monthly investigated from April 2009 to November 2009. The intense rainfall occurred at between July and August and the hydrological factors were highly varied during the rainfall season. By the concentrated rainfall, the elevation, influx and efflux were sharply increased and the turbid water was also flowed into the middle water column in Lake. The inflow of turbid water increased the nutrient concentrations in water body and this appears to stimulate of phytoplankton regard as the primary productivity of influx of organic matter. Monthly average concentration of dissolved organic carbon (DOC) was generally higher than the particulate organic carbon (POC) concentration in Lake, but Temporal and spatial variation of POC concentration was higher than DOC and the maximum POC concentration was recorded in surface water in August, had the highest phytoplankton biomass. Organic carbon concentration in inflow site was rarely changed during the dry season, but the concentration was rapidly increased by the initial intense rainfall. In organic matters budget, the most of the organic matters was inflowed from the inflow site at rainfall season. Especially, the influx of allochthonous organic matters during the intense rainfall was 72.4% in the total influx organic matters.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.2
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• pp.63-70
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• 2001

Changes in concentrations of dissolved oxygen, ammonia, nitrate, pH, Fe and Mn were monitored from the laboratory incubation of an benthic chamber. The extent of sedimentary organic carbon and nitrogen decomposition was quantified by applying the concentration data to the chemical reaction equations of early diagenesis. The patterns of the concentration changes, observed during the 237 hr long incubation experiment, made it possible to divide the entire experiment period into four characteristic sub-periods (0-9 hr, 9-45 hr, 45-141hr, 141-237 hr). C/N ratio, estimated for each sub-period, was 6.63, 1.49, 0.81 and 0.02, respectively. This sequential decrease in C/N ratio suggests that during the incubation experiment dissolved nitrogen species diffuse more out of the sediment than dissolved carbon species. Greater diffusion of nitrogen indicates the preferential decomposition of organic nitrogen during early diagenesis of sedimentary organic matter. Comparison of the concentration data (sedimentary organic carbon and nitrogen, porewater organic carbon and ammonia)between the sediment pre and post incubation also indicates the preferential decomposition of nitrogen during early diagenesis of sedimentary organic matter.