• Journal of Environmental Science International
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• v.16 no.12
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• pp.1393-1399
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• 2007

This research helps you understand the road traffic noise levels by using a noise map. We have observed the change of the road traffic noise levels around $07:00{\sim}08:30\;and\;22:00{\sim}23:00$ using the noise map in the city. The road traffic noise level is very high both at noon and at night around a beltway and an interchange that is linked with a highway. It seems that the main route of so many vehicles, which are at neighboring cities such as N city and D and H districts and which avoid traffic jams in the city, is the beltway and interchange. The road traffic noise level of a nearby express bus terminal, railroad station, and airport is more than 75 dB at noon and 65 dB at night. The road traffic noise level of G city at night is observed to be more than 55 dB. The noise levels of a residence area and a university are higher than a road with high noise levels when the commuters drive to work. The end of the day exceeds 11 o'clock because of a culture level of development that arouses spare time, eating out, adults' drinking culture, nightlife of the youth, etc. Therefore, the road traffic noise level is high during late night hours, and it exceeds regulatory guidelines(55 dB(A)). It also damages the residence area that is located near the road.

• Journal of Environmental Science International
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• v.18 no.2
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• pp.205-213
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• 2009

A laboratory experiment was conducted to investigate nitrogen removal from plating wastewater by a soil reactor. A combination of soil, waste oyster shell and activated sludge were used as a loading media in a soil reactor. The addition of 20% waste oyster shell and activated sludge to the soil accelerated nitrification (88.6% ${NH_4}^{+}-N$ removal efficiency) and denitrification (84.3% ${NO_3}^{-}-N$ removal) in the soil reactor, respectively. In continuous removal, the influent ${NH_4}^{+}-N$ was mostly converted to nitrate nitrogen in the nitrification soil reactor and only a small amount of ${NH_4}^{+}-N$ was found in the effluent. When methanol was added as a carbon source to the denitrification soil reactor, the average removal efficiency of ${NO_3}^{-}-N$ significantly increased. The ${NO_3}^{-}-N$ removal by methanol addition in the denitrification soil reactor was mainly due to denitrification. The phosphorus was removed by the waste oyster shell media in the nitrification soil reactor. Moreover, the phosphorus removal in the denitrification soil reactor was achieved by synthesis of bacteria and the denitrification under anaerobic conditions. The approximate number of nitrifiers and denitrifiers was $3.3{\times}10^5\;MPN/g$ soil at a depth of $1{\sim}10\;cm$ and $3.3{\times}10^6\;MPN/g$ soil at a depth of $10{\sim}20\;cm$, respectively, in the soil reactor mixed with a waste oyster shell media and activated sludge.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.4
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• pp.451-457
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• 2011

Purple non-sulfur (PNS) bacterium $Rhodobacter$ $sphaeroides$ KD131 was studied with the aim of achieving maximum hydrogen production using various carbon and nitrogen sources at different pH conditions. Cells grew well and produced hydrogen using $(NH_4){_2}SO_4$ or glutamate as a nitrogen source in combination with a carbon substrate, succinate or malate. During 48h of photo-heterotrophic fermentation under 110$W/m^2$ illumination using a halogen lamp at $30^{\circ}C$, 67% of 30mM succinate added was degraded and the hydrogen yield was estimated as 3.29mol $H^2$/mol-succinate. However, less than 30% of formate was consumed and hydrogen was not produced due to a lack of genes coding for the formate-hydrogen lyase complex of strain KD131. Initial cell concentrations of more than 0.6g dry cell weight/L-culture broth were not favorable for hydrogen evolution by cell aggregation, thus leading to substrate and light unavailability. In a modified Sistrom's medium containing 30mM succinate with a carbon to nitrogen ratio of 12.85 (w/w), glutamate produced 1.40-fold more hydrogen compared to ammonium sulfate during the first 48h. However, ammonium sulfate was 1.78-fold more effective for extended cultivation of 96h. An initial pH range from 6.0 to 9.0 influenced cell growth and hydrogen production, and maintenance of pH 7.5 during photofermentation led to the increased hydrogen yield.

• Journal of Environmental Science International
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• v.17 no.12
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• pp.1343-1351
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• 2008

The activated sludge obtained from wastewater coke oven plant was immobilized by entrapment with polyethylene glycol (PEG). The effects of several factors on the biodegradation of $CN^-$ from. synthetic wastewater were investigated using batch and continuous reactors. The degradation rate of $CN^-$ increased with increasing of the immobilized bead volume in the reactor. Approximately 7.65mg/L of $NH_4-N$ was produced upon the degradation of 35mg/L of $CN^-$. When high concentrations of the toxic cyanide complex were used in the testing of cyanide degradation, the free activated sludge could be inhibited more than that of the immobilized activated sludge. When the phenol concentration was higher than 400mg/L in the synthetic wastewater, approximately 98.4% of $CN^-$ was removed within 42 hours by the immobilized activated sludge. However, the cyanide was not completely degraded by the tree activated sludge. This indicates that high phenol concentrations can act as a toxic factor for the free activated sludge. A $CN^-$ concentration of less than 1mg/L was achieved by the immobilized sludge at the loading rate of 0.025kg $CN^-/m^3-d$. Moreover, it was found that the HRT should be kept for 48 hours in order to obtain stable treatment conditions.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.3
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• pp.87-95
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• 2003

Although extensive studies were conduced on hydrogen fermentation of organic wastewaters, little is known about biohydrogen production from organic solid wastes. The leaching-bed reactor treating food waste by heat-shocked anaerobic sludge was, therefore, operated at D of 2.1, 3.6, 4.5 and $5.5d^{-1}$ to find optimal D for hydrogen production. Successful operation of a reactor can be accomplished when it is operated at proper dilution rate (D). Operation at high D leads to the washout of biomass in the reactor while operation at low D leads to product inhibition due to the accumulation of excess VFA. These appear to limit the production of hydrogen to reach a higher level. All the reactors showed that, on day 1-3, hydrogen production was dominant and VFA concentration was higher than ethanol. Butyrate and acetate were major components of VFAs over the whole operation, though lactate was very high on day 1-2. Compared with other D values, D of $4.5d^{-1}$, resulted in higher butyrate/acetae (B/A) ratios during the fermentation. The trend of B/A ratios was similar to the hydrogen production, suggesting that butyrate formation favored hydrogen production. Ethanol increased significantly from day 4 when hydrogen Production stopped. It indicated that heat-shocked sludge was able to induce a metabolic flow from hydrogen-and acid-producing pathway to solvent-producing pathway. Operation at D of $4.5d^{-1}$ led to higher fermentation efficiency (58%) than those (51.5, 55.3 and 53.7%) at 2.1, 3.6 and $5.5d^{-1}$. The COD removed was convened to hydrogen (10.1%), VFA (30.9%), and ethanol (17.0%).

• Particle and aerosol research
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• v.7 no.4
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• pp.131-138
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• 2011

The concentration levels of n-alkanes and water soluble organic carbon (WSOC) at Anmyon, a Global Atmospheric Watch (GAW) station operated by Korea Meteorological Administration (KMA), has been characterized for the PM10 samples collected in 2010. It was found that the concentrations of WSOC at Anmyon were comparable to those in Seoul and lower than those in Gosan, another background area in Korea. However, the maximum concentration of the WSOC at Anmyon was observed in fall while that at Seoul was in winter. It suggests that the emission and/or transformation characteristics at two areas are different. The concentrations of n-alkanes at Anmyon were slightly lower than at Gosan and about one thirds at Seoul. However, it was found that at Gosan the n-alkanes from natural sources were dominant at Gosan. On the other hand, n-alkanes from anthropogenic sources were dominant at Anmyon. Study directions to further understand the characteristics of aerosols at Anmyon are discussed.

• Asian Journal of Atmospheric Environment
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• v.6 no.1
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• pp.53-66
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• 2012

A comparison of analytical approaches for Levoglucosan ($C_6H_{10}O_5$, commonly formed from the pyrolysis of carbohydrates such as cellulose) and used for a molecular marker in biomass burning is made between the four different analytical systems. 1) Spectrothermography technique as the evaluation of thermograms of carbon using Elemental Carbon & Organic Carbon Analyzer, 2) mass spectrometry technique using Gas Chromatography/mass spectrometer (GC/MS), 3) Aerosol Mass Spectrometer (AMS) for the identification of the particle size distribution and chemical composition, and 4) two dimensional Gas Chromatography with Time of Flight mass spectrometry (GC${\times}$GC-TOFMS) for defining the signature of Levoglucosan in terms of chemical analytical process. First, a Spectrothermography, which is defined as the graphical representation of the carbon, can be measured as a function of temperature during the thermal separation process and spectrothermographic analysis. GC/MS can detect mass fragment ions of Levoglucosan characterized by its base peak at m/z 60, 73 in mass fragment-grams by methylation and m/z 217, 204 by trimethylsilylderivatives (TMS-derivatives). AMS can be used to analyze the base peak at m/z 60.021, 73.029 in mass fragment-grams with a multiple-peak Gaussian curve fit algorithm. In the analysis of TMS derivatives by GC${\times}$GC-TOFMS, it can detect m/z 73 as the base ion for the identification of Levoglucosan. It can also observe m/z 217 and 204 with existence of m/z 333. Although the ratios of m/z 217 and m/z 204 to the base ion (m/z 73) in the mass spectrum of GC${\times}$GC-TOFMS lower than those of GC/MS, Levoglucosan can be separated and characterized from D (-) +Ribose in the mixture of sugar compounds. At last, the environmental significance of Levoglucosan will be discussed with respect to the health effect to offer important opportunities for clinical and potential epidemiological research for reducing incidence of cardiovascular and respiratory diseases.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.3
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• pp.303-312
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• 2011

Data on the energy usage including biomass, emissions of air pollutants ($SO_x$, $NO_x$, CO), and the air quality in North Korea are analyzed. The energy usage in North Korea has decreased in the 1990s and thus, the emission amount of air pollutants. Coal and biomass constitute a major fraction of energy sources since the 1990s. It is identified that the emission amount of air pollutants per unit energy consumption in North Korea is much higher than South Korea for the period data are available (since 1990) implying that the air pollutant emission management system in North Korea is inadequate. In particular, the amount of biomass burning for household cooking and heating is significant with the huge emissions of air pollutants such as CO and organic species both in the gas and aerosol phase. Furthermore, it is found that the existing energy usage and air pollutant emission data are not consistent in biomass burning related data.

• Journal of Environmental Science International
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• v.18 no.4
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• pp.389-400
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• 2009

In this research, we measured the number of lanes, distance, disposition of apartment that are affecting the road traffic noise to evaluate the current condition of G city's road traffic noise. We decide on a basis regarding an apartment price formation factor, and the apartment current price and the results that compared. To have a point scale, we set the maximum road traffic noise at a 8 lane road for 5 points, give 4 points for a 6 lane road, which has a $2.1{\sim}2.5\;dB(A)$ difference compared to a 8 lane road, give 3 points for a 4 lane road, which has a $5.2{\sim}5.5\;dB(A)$ difference compared to a 8 lane road, and set 2 points for a 2 lane road and lower. If we set the standard floor plan as horizontal and a living room facing the roadside, the horizontal and living room facing the opposite side of the road is 1 point because it differs by 14.1 dB(A), and the vertical is 3 points since the difference is 5.3 dB(A). If we make grades by the distance, making standard the fifth floor with little soundproof effect from apartment to road, we observe a measurement below 2.9 dB(A) at a distance of less than 10 m and 5 dB(A), decreased at a distance of 20 m. Therefore, 4 points were given for less than 10m, 3 points for $10{\sim}20\;m$, 2 points for more than 20 m as we can apply the effect of a decay distance of line sound source and the decrease in noise effects of more than 6 dB(A), 1 point for more than 40m, and 0 points for more that 80 m since it is negligible. 28 apartments got 0 points because there is no effect of road traffic noise from other apartments, and 50 apartments where only the road at one side effect them got $5{\sim}10$ points. 4 apartments (17-2, 6-3, 10-4, 3-3) received over 20 points. 15 cases showed a difference between developer price and resale price, and 11 cases (73%) among them showed the same trend (price increases with a low road traffic noise restriction factor point) with the point of road traffic noise restriction factor. 4 cases demonstrated the opposite trend, showing price increases with a high restriction factor point. Among the 4 cases, case numbers 2,6 and 9 appear to be more affected by the location factor (business district) than the road traffic noise restriction factor, and case number 1 appears to be affected by the building factor (openness and direction).

• KSBB Journal
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• v.20 no.6
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• pp.401-407
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• 2005

Optimum culture conditions and medium composition for hydrogen production by Clostridium beijerinckii KCTC 1785 were investigated. Initial pH and temperature for growth were 7.0 and $35^{\circ}C$, respectively. Agitation accelerated the hydrogen production. Although C. beijerinckii KCTC 1785 could grow up to 6%(w/v) glucose in the medium, the optimum glucose concentration for hydrogen production was 4% and hydrogen content in the biogas was 37%(v/v). However, the economical glucose concentration for hydrogen production was 1% regarding to the residual glucose which was not used in the medium. During hydrogen fermentation, acetic and butyric acid were produced simultaneously. High concentrations of acetic(>5,000 mg/L) or butyric(>3,000 mg/L) acid inhibited hydrogen production. When pH was maintained at 5.5 in the batch fermentation, 1,728 mL of hydrogen was produced from 0.5% glucose within 15 hr. $H_2$ yield was estimated to be 1.23 mol $H_2/mol$ glucose. It was found that yeast extract or tryptose in the medium was essential for hydrogen production.