• Journal of the Korean GEO-environmental Society
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• v.15 no.5
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• pp.39-46
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• 2014

The objectives of this study were to determine biodegradation and characteristics of BTEX and MTBE under aerovic-anaerobic conditions and evaluate the potential of natural attenuation method in denitrifying condition.. In the single-substrate experiments, all of the BTEX compounds were degraded under all the conditions. but, lower degradation of benzene and p-xylene were observed under aerobic condition due to the lack of oxygen initially supplied. In the mixed-substrate experiments, BTEX degradation was delayed compared to that in the single-substrate experiments due to a competition of the substrates. Biodegradation of MTBE was observed only under denitrifying conditions and we expected that MTBE mineralized to $CO_2$ without the accumulation of TBA. We also conducted to determine the effect of initial nitrate concentration on BTEX and MTBE degradation. At low nitrate concentration (<50 mg/L), BTEX degradations were limited by the lack of electron acceptor and BTEX degradation was inhibited at high nitrate concentration (>200 mg/L). The results in this study indicated that biotransformation could be applied to the gasoline-contaminated region under aerovic-anaerobic.

• Korean Journal of Ecology and Environment
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• v.34 no.2 s.94
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• pp.81-89
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• 2001

In order to know relationships between green euglenoids and environmental factors, the species composition and density were assessed for 12 months together with environmental variables in the Jeonjucheon urban drainage, Korea. Nitrate was a high of 3.22 mg/1 in June and phosphate concentration was over 0.71 mg/l in the winter. The euglenoids totaled 5 genera and 71 species throughout the year, increasing in the early summer (35 to 42 texa) and decreasing in the winter (below 20 taxa). The number of green euglenoids positively correlated with surface water temperature. the total density of the green euglenoids showed a typical bimodal pattern, being maximal in the winter (5,394 cells/ml in June). The winter peak was a result of active growths of Euglena caudata, E. geniculata and E. viridis, however, each of which positively correlated with the phosphate. The early summer peak was attributed to Euglena deses, Lepocinclis ovum, and Phacus trypanon, each of which positively correlated with the ammonium and nitrate. The complete bimodal spectrum of species number and density of green euglenoids provides a sensitive image in detecting the changes of environmental variables in polluted waters such as Jeonjucheon.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.971-976
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• 2008

Water pollution by ammonium ion and nitrate is a common and growing problem in the ecosystem. Process of biological removal consists of nitrification and denitrification by bacteria. Ammonium is oxidized generally to nitrate by nitrification and nitrate is reduced to dinitrogen gas in the subsequent denitrification process. Although natural zeolite is well known for its ability to preferentially remove ammonium, it is not sufficiently removing ammonium ion and nitrate by adsorption. In order to overcome this problem, a method of biological removal with zeolite is used for simultaneous removal of ammonium and nitrate. As a result, in case of shaking culture with 1% seed and passing through zeolite column, the process revealed that ammonium ion could be removed completely after 14 hours. The removal of nitrate using columns with naturally adsorbed bacteria onto zeolite reached approximately 100% after 4 hours.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.10a
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• pp.83-84
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• 2014

This study evaluated the effectiveness of biostimulating agent in contaminated coastal sediment. The study was conducted via column tests in coastal sea wherein two separate columns were employed for two different polymers used and another column for a blank. The biostimulating agent was made by mixing sea sediment with biostimulants viz acetate, nitrate, sulfate. The biostimulating agent was then rolled into balls, dried and coated with either Cellulose Acetate (CA) or Polysulfone (PS) to control the release of the biostimulants. The pH was around 7.6~8 for 4 months while COD, TP and TN were significantly lower in the column containing biostimulating agents. Heavy metal(Fe, Zn, Cd, Cr, Pb, Cu) was converted to stable forms and PS coated biostimulating agent had a high efficiency of heavy metals distribution.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.46-47
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• 2013

We prepared biostimulant balls using sea sediment mixed with biostimulants viz acetate, nitrate and sulfate. The Biostimulant balls were coated with Cellulose Acetate (CA) and Polysulfone (PS) to control the release of the biostimulants. SEM images showed that CA coating was porous and irregular in the inside and very uniform and tight like beehive while PS coating was the same in the inside and outside and not porous. Biostimulants release was found to be high in sea water compared to distilled water. The release of nitrate was higher compared to sulfate. In turbulent environment the release of bionutrients was 50% higher than static environment.

• Journal of the Mineralogical Society of Korea
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• v.17 no.2
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• pp.147-155
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• 2004

Anion adsorption properties of organobentonites modified by two cationic polymers, hexadecyltrimmethylammonium (HDTMA) and cetylpyridinum (CP), were investigated. The organobentonites showed the significant expansion of basal spacing to 42.0 $\AA$ at room temperature. The adsorption experiments were conducted for the 0.2 g of organobentonites with 40 mL solutions of various concentrations of anions such as nitrate, sulfate and phosphate. As a result, the organobentonites showed excellent adsorption capacities for those anions whereas untreated bentonite showed very low adsorption capacity. Adsorption rate of HDTMA-bentonite was about 90% for 100 mg/L solutions of nitrate and phosphate, and that of CP-bentonite was 97% for 100 mg/L solution of nitrate. Adsorption behaviors were slightly different for the different organobentonites and anions. Both organobentonites showed relatively higher adsorption rate for nitrate and phosphate than sulfate. Therefore, these organobentonites showing high anion adsorption capacities can be used far the removal of deleterious anions in the treatment of environmental pollution.

• Korean Journal of Environmental Biology
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• v.17 no.4
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• pp.427-438
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• 1999

Differential growth of Ulva pertusa Kjellman was observed in response to different photon irradiances and seawater. Growth rate of U. pertusa cultivated in the seawater collected from the East Sea was significantly higher than that in the seawater collected from the Yellow Sea. Optimal growth was found at $100{\mu} molm^{-2} s^{-1}$ in both cases. Chlorophyll contents of U. pertusa grown in the east sea water were higher than that cultivated in the west sea water at irradiances lower than $60{\mu} molm^{-2} s^{-1}$. At irradiances higher than $100{\mu} molm^{-2} s^{-1}$, there was no difference in chlorophyll content in between the two different sea waters with tendency that pigmentation decreased with increasing photon irradiances. Nitrate concentration in the west sea water was 2-fold higher than that in the east sea water, while phosphorus concentrations (0.03 ppm) were similar. Concentrations of $Cu^{2+}$ and $Pb^{2+}$ were 0.004 and 0.003 ppm respectively which are far below environmental standard concentrations (0.02 ppm for $Cu^{2+}$ and 0.1 ppm for $Pb^{2+}$). Taking those data into account, we have done laboratory investigations into the effects of inorganic nutrients and heavy metals on U. pertusa. As nitrate concentration increased from 0.5 to 5 ppm, growth rate of U. pertusa increased, but different concentrations of phosphorus did not cause any differential effect. On the other hand, chlorophyll contents increased with increasing phosphorus concentrations. Copper of U. pertusa be toxic decreased the growth and pigmentation as the concentration increased, whereas lead showed no such effect. Concentrations of $Cu^{2+}$ employed in the present study were much higher than those in ambient seawater. Intermittent soaring of $Cu^{2+}$ level as observed in natural seawater could, however, seriously damage the growth behaviour of U. pertusa.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.3
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• pp.247-252
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• 2002

In this technical information, the TSP measurement data at Gosan between 1992 and 1999 are presented and analyzed. The average ratio of N $O_3$$^{[-10]}$ /nss-S $O_4$$^{2-}$ is highest in March. The annual average ratio concentration of N $O_3$$^{[-10]}$ increased and it was found that the annual average ratio of N $O_3$$^{[-10]}$ /nss-S $O_4$$^{2-}$ increased during the period, probably due to the change of emission characteristics of China.

• Journal of Navigation and Port Research
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• v.29 no.6 s.102
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• pp.589-593
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• 2005

A laboratory study on the adsorption of nitrate in polluted coastal water using various materials including several types of dredged sediments(ST) and yellow c1ays(YC), which are activated by heat(HT), bioleaching for heavy metal removal(BL) and neutralization(NR) was performed. The equilibrium time of the adsorption for the sediment bioleached and treated by heat(BL-HT-ST) was only 17min which was faster than the sediment bioleached, neutralized and treated by heat(BL-NR-HT-S) (25min) or the sediment treated by the bioleaching process(BL -ST)(27min), but longer equilibrium times for yellow c1ay(YC) or heat treated yellow day(HT- YC) were required. The adsorption processes of nitrate in sea water for tested material could be described by Freundlich isotherm, but were significantly affected by surface characteristics of the materials. The adsorption capacities for raw sediment and heat treated sediment were 2.12 and 2.19mg NO3-N/g, respectively, which were higher than others, indicating that the sediment activated by heat could be used as a material for the improvement of nearshore water quality.

• Economic and Environmental Geology
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• v.49 no.3
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• pp.167-179
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• 2016

Water quality of Oseepchun, Dogye area, was investigated quantitatively for its origin and hydrogeochemistry in relation to the influence of groundwater. Groundwater appears to be the principal source of Oseepchun from the water-quality monitoring data including redox potentials, composition of dissolved ions and their correlations, hydrogen and oxygen stable isotopic ratios, and the distribution and occurrence of contaminants. Water-quality type of the surface water was grouped by the water-rock interactions as $Ca-HCO_3$ type originated from carbonated bed-rocks in the Joseon Supergroup, (Ca, Mg)-$SO_4$ type related with dissolution of surfide minerals in coal beds of Pyeongan Supergroup, and (Ca, Mg)-($HCO_3$, $SO_4$) type of the mixed one. Locally water pollution occurs by high $SO_4$ from mine drainage and $NO_3$ from waste-treatment facility. Intensive precipitation in summer has no effect on the water type of Oseepchun, but increases the inflow of nitrate and chloride originated from land surface. Results of this study direct that groundwater-surface water interaction is intimate, and thus surface-water resource management should begin with groundwater characterization.