• Journal of Korean Society of Environmental Engineers
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• v.28 no.1
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• pp.34-41
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• 2006

The objectives of this study were to investigate the affecting factors on streaming current(SC) and to evaluate set point(SP). For the study, a pilot scale apparatus with a capacity of 12 L/min was operated at Guui water intake of Seoul. SC was monitored with varying poly aluminium chlorides(PACs) dose and water quality parameters like conductivity, turbidity, temperature, and pH. The removal efficiencies were evaluated in terms of turbidity and dissolved organic carbon(DOC) with varying coagulation conditions. The effects of affecting factors on SC and SP were also estimated. According to the result observed from the variation of SC with water quality parameters during the experimental period, tendencies of SC and conductivity were very similar, and SC and conductivity had a strong linear relation. At the optimum condition of coagulation, SP decreased as the rainy season changed to the dry season, during the experimental period. Especially, in condition of low turbidity, conductivity had relatively more effect on SC than turbidity. As conductivity increased, SP decreased and coagulant dose per unit increase of SC gradually increased. In view of the results so far obtained, it may be possible to determine the SP range considering the real time variation of water quality, especially conductivity.

• Applied Biological Chemistry
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• v.41 no.5
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• pp.384-389
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• 1998

The herbicide propanil and its metabolite, DCA were incubated with oxidative catalysts in the presence or absence of humic monomers to evaluate the incorporation of them into humic substances. Propanil and DCA underwent little or no transformation by oxidatve catalysts in the absence of humic monomers. In the presence of humic monomers, the most effective co-substrate for transformation of propanil was syringic acid by laccase and HRP, that of DCA was catechol by laccase and HRP, and protocatechuic acid by birnessite. The transformation of DCA was the highest when it was incubated with catechol at pH 8.0 during 24 hrs by laccase, and with catechol at pH 3.0 during 2 hrs by HRP, and with protocatechuic acid at pH 5.0 during 2 hrs by birnessite. The DCA transformation increased with increasing concentration of humic monomers. The transformation of DCA was increased with about 5 times when it was incubated with lactase and birnessite together than lactase alone, but that of it was not effected when it was incubated with HRP and birnessite together. When DCA was incubated with dissolved organic carbon in the presence of oxidative catalysts, the transformation of it was not increased by laccase and birnessite but increased by HRP.

• Journal of environmental and Sanitary engineering
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• v.16 no.3
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• pp.96-103
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• 2001

This study was carried out to investigate the major factors for the removal of NOMs (Natural Organic Matters) by alum ferric chloride and blended coagulants that consisted of alum and ferric chloride. Investigated factors were pH, the dosage of coagulant, alkalinity, hardness and bloc strength. The particle size contained in the test water came from the Han River was also measured. DOC(Dissolved Organic Carbon) removal at pH 6 was two to three times higher than at pH 8.5. The blended coagulant showed 9 to 10 percent higher DOC removal efficiency and 2 to 4 percent higher turbidity under the same condition. Alkalinity consumption of alum, ferric chloride and blended coagulant was 81%, 90% and 86% of theoretical value, respectively. The limit concentration of alkalinity to avoid pin floe was 10 mg $CaCO_3/L$ when alum was used. Hardness had no apparent effect on coagulation. The residual turbidity and $UV_{254}$ showed a tendency of increasing with floc strength($sec^{-1}$) increase. The order of floe strength was the following; alum >blended coagulant > ferric chloride. The particle counter test showed 89 percent of the small particle size(SPS, $1~5{\;}{\mu}textrm{m}$) and 11 percent of the medium to large particle size(M.LPS, $5~125{\;}{\mu}textrm{m}$). At PH7.85, the particle removal efficiencies of SPS($1~5{\;}{\mu}textrm{m}$) and M.LPS($5~125{\;}{\mu}textrm{m}$) in the coagulation process were 81% and 95%, respectively.

• Korean Journal of Environmental Biology
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• v.28 no.3
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• pp.125-132
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• 2010

In order to assess the effect of pollution on marine ecosystem, we examined the plankton health assessment at 16 stations during summer season in Jinhae Bay. The organic and inorganic pollutant sources (dissolved organic carbon; DOC, chemical oxygen demand; COD and Chlorophyll a; Chl.a), including planktonic orangism such as enterobacteria Escherichia coli, heterotrophic bacteria (HB), autotrophic nano-flagellates (ANF), heterotrophic nano flagellates (HNF), ciliate and harmful algal bloom species (HABs) were used to characterize marine ecosystem health assessment. Of these, we tentatively selected those items Chl.a, HABs, HB and E. coli for plankton health index (PHI). Also, the scoring criteria for each metric were based on a statistical analysis and then, the grades are rated on four levels. As a result, the ecological assessment of these data reveals that PHI in Jinhae Bay is rated as "Good or fair" for overall conditions. The present study suggests that the PHI might be considered as one of important management tool to assess marine ecosystem health of Jinhae Bay.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.5
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• pp.332-340
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• 2009

This study was conducted to analyze and determine formation potentials for chlorination disinfection by-products (DBPs) from twenty amino acid compounds with or without $Br^-$. Two of twenty amino acid compound were tryptophan and tyrosine that were relatively shown high for formation of trihalomethanes (THMs)/dissolved organic carbon (DOC) whether or not $Br^-$ presented. Other 18 compounds were shown low for formation of THMs/DOC whether or not $Br^-$ presented. Five amino acid compounds that were tryptophan, tyrosine, asparagine, aspartic acid and histidine were shown high for formation of haloacetic acids (HAAs)/DOC whether or not $Br^-$ presented. Although formation of dichloroacetic acid (DCAA) was dominated in asparagine, aspartic acid and histidine, trichloroacetic acid (TCAA) was dominated in tryptophan and tryptophan. The formation of haloacetnitriles (HANs)/DOC whether or not $Br^-$ presented was high in Aspartic acid, histidine, asparagine, tyrosine and tryptophan. Specially, aspartic acid was detected 660.2 ${\mu}$g/mg (HAN/DOC). Although the formation of chloralhydrate (CH)/DOC was shown high in asparagine, aspartic acid, histidine, methionine, tryptophan and tyrosine, the formation of Chloropicrin (CP)/DOC was low (1 ${\mu}$g/mg) in twenty amino acid compounds. The formations of THM, HAA and HAN were also investigated in functional groups of amino acids. The highest formation of THM was shown in amino acids compounds (tryptophan and tyrosine) with an aromatic functional group. Highest, second-highest, third-highest and fourth-highest functional groups for formation of HAA were aromatic, neutral, acidic and basic respectively. In order of increasing functional groups for formation of HAN were acidic, basic, neutral and aromatic.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.4
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• pp.519-534
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• 2019

When the fresh water from the artificial lakes (Ganwolho and Bunamho) were discharged to Cheonsu Bay in summer to prevent the flood over the reclaimed farmland near the lakes, the impact on water qualities (nutrients, organic matters, trace metals) within the bay was investigated through four surveys (June, July, August and October, 2011). Dissolved inorganic nitrogen (DIN) increased about as much as 3-4 times over the whole water column when the freshwater was discharged. And the main species composition of DIN changed from ammonia to nitrate. Dissolved inorganic phosphorus (DIP) decreased as much as 2 times in surface waters, but increased as much as 1.5 times in deep waters, and also silicate concentrations increased as much as 3-4 times in deep waters of the inner bay. The N/P ratios in Chunsu bay seawaters were much higher (2 to 7 times) than the Redfield ratio when the freshwaters were discharged, which indicated the phosphorus limiting in the phytoplankton growth. Dissolved organic carbon (DOC) and nitrogen (DON) increased as much as about 2 times. In addition, particulate organic matters (POC, PON, POP, Bio-Si) increased as much as above 2 times in the surface waters of the inner bay. Trace metals (Fe, Mn, Co, Ni, Cu) increased in the surface waters of the inner bay, but dissolved Cd concentrations decreased as much as 2 times. Therefore, when the contaminated fresh waters from the artificial lakes were discharged into the bay, nutrients, organic matters and trace metals generally increased compared to normal period. Since the phytoplankton bloom occurred in the surface waters of the inner bay, dissolved oxygens at the surface waters were oversaturated and hence hypoxic in the deep waters. Highly enriched nutrients concentrations were found in deep waters of the inner bay, which was accompanied with the hypoxic condition. Finally, the water quality in the inner bay of the Chunsu bay was deteriorated from less than grade 3 in normal periods to grade 5 when the freshwaters from the artificial lakes were discharged in summer.

• Journal of Environmental Science International
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• v.11 no.3
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• pp.241-246
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• 2002

One of the Musty and earthy smell compounds in raw water is generally attributed to 2-methylisoborneol (2-MIB). It is well known that activated carbon and oxidants such as $O_3$, Cl $O_2$, are effective ways to control 2-MIB. In isotherm equilibrium experiments, 2-MIB in distilled water was much more adsorbed to the activated carbon(A/C) than raw water containing dissolved organic carbon (DOC). The Freundlich constants(k) of distilled water and raw water were 3.36 and 0.049, and 1/n values were 0.80 and 0.42, respectively. The 2-MIB residual rate were Y = $e^{-0}$.55x/~ $e^{-0}$.54x/ with Ozone( $O_3$) dose by 5 minutes contact time at the 241 and 353 ng/L initial concentrations. The 2-MIB residual rate were Y = $e^{-0}$.32x/~ $e^{-0}$.35x/ with Chlorine dioxide(Cl $O_2$) dose by 15 minutes contact time at the 89 and 249 ng/L initial concentrations. 2-MIB was decreased from 1911 ng/L to 569ng/L by post-ozonation(70%removal efficiency) and removal efficiencies of 2-MIB by the following 4 kinds Granular Activated Carbon(GAC) process such as coal base, coconut base, wood base and zeolite＋carbon base were 95.8, 89.5, 88.4, and 93.7% respectively.ely.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.2
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• pp.109-120
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• 2007

The information on flowpath, storage, residence time, and interactions of water and carbon transport in a catchment is the prerequisite to the understanding and predicting of water and carbon cycling in the mountainous landscapes of Korea. In this paper, along with some up-to-date results, we present the principal methods that are currently used in HydroKorea and CarboKorea research to obtain such information. Various catchment hydrological processes have been examined on the basis of the water table fluctuations, the end-member mixing model, the cross correlation analysis, and cosmogenic radioactive isotope activity. In the Gwangneung catchment, the contribution of surface discharge was relatively large, and the changes in the amount, intensity and patterns of precipitation affected both the flowpath and the mean residence time of water. Particularly during the summer monsoon, changes in precipitation patterns and hydrological processes in the catchment influenced the carbon cycle such that the persistent precipitation increased the discharge of dissolved organic carbon (DOC) concentrated in the surface soil layer. The improved understanding of the hydrological processes presented in this report will enable a more realistic assessment of the effects of climate changes on the water resource management and on the carbon cycling in forest catchments.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.965-972
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• 2010

The objective of this research was to evaluate for the changes of pore structures and adsorption capacities due to the increase the numbers of reactivation. The reactivated GAC had experienced three cycles of water treatment and thermal reactivation. The pore size distributions of virgin and reactivated GACs were very different. The virgin GAC was mostly microporous (< $15\;{\AA}$), with less mesopores ($20{\sim}100\;{\AA}$). The reactivated GACs was mostly mesoporous ($20{\sim}100\;{\AA}$), with less micropores (< $15\;{\AA}$). The specific surface area and total pore volume were reduced as the number of reactivation increased. The maximum adsorption capacity (X/M) of virgin GAC ($964.6\;{\mu}g/g$) for $CHCl_3$ was 2~3 times larger than 1st~3rd reactivated GAC ($255.6{\sim}399.5\;{\mu}g/g$). The maximum adsorption capacity (X/M) of virgin GAC (19.5 mg/g) for DOC (dissolved organic carbon) was equal to that of 1st~3rd reactivated GAC (18.0~18.7 mg/g).

• Journal of Soil and Groundwater Environment
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• v.22 no.5
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• pp.30-39
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• 2017

In this study, the predictive toxicity of barley Hordeum vulgare was estimated using a modified terrestrial biotic ligand model (TBLM) to account for the toxic effects of $CuOH^+$ and $CuCO_3(aq)$ generated at pH 7 or higher, and this was compared to that from the original TBLM. At pH values higher than 7, the difference in $EA_{50}\{Cu^{2+}\}$ (half maximal effective activity of $Cu^{2+}$) between the two models increased with increasing pH. As Mg concentration increased from 8.24 to 148 mg/L in the pH range of 5.5 to 8.5, the difference in $EA_{50}\{Cu^{2+}\}$ increased, and it reached its maximum at pH 8. The difference in $EC_{50}[Cu]_T$ (half maximal effective concentration of Cu) between the two models increased as dissolved organic carbon (DOC) concentration increased when pH was above 7. Thus, for soils with alkaline pH, the toxic effect of $CuOH^+$ and $CuCO_3(aq)$ are greater at higher salt and DOC concentrations. The acceptable Cu concentration in soil porewater can be estimated by the modified TBLM through deterministic method at pH levels higher than 7, while combination of TBLM and species sensitivity distribution through the probabilistic method could be utilized at pH levels lower than 7.