• International Journal of Highway Engineering
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• v.16 no.5
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• pp.49-58
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• 2014

PURPOSES : In areas of high traffic volume, such as expressway across large cities, the amount of nitrogen oxides (NOx) emitted into the atmosphere as air pollution can be significant since NOx gases are the major cause of smog and acid rain. Recently, the importance of NOx removal has arisen in the world. Titanium dioxide ($TiO_2$), that is one of photocatalytic reaction material, is very efficient for removing NOx. The NOx removing mechanism of $TiO_2$ is the reaction of solar photocatalysis. Therefore, $TiO_2$ in road structure concrete need to be contacted with ultraviolet rays (UV) to be activated. In general, $TiO_2$ concretes are produced by replacement of $TiO_2$ as a part of concrete binder. However, considerable portion of $TiO_2$ in concrete cannot contact with the pollutant in the air and UV. Therefore, $TiO_2$ penetration method using the surface penetration agents is attempted as an alternative in order to locate $TiO_2$ to the surface of concrete structure. METHODS : This study aimed to evaluate the NOx removal efficiency of photocatalytic concrete due to various $TiO_2$ application method such as mix with $TiO_2$, surface spray($TiO_2$ penetration method) on hardened concrete and fresh concrete using surface penetration agents. The NOx removal efficiency of $TiO_2$ concrete was confirmed by NOx Analyzing System based on the specification of ISO 22197-1. RESULTS : The NOx removal efficiency of mix with $TiO_2$ increased from 11 to 25% with increasing of replacement ratio from 3 to 7%. In case of surface spray on hardened concrete, the NOx removal efficiency was about 50% due to application amount of $TiO_2$ with surface penetration agents as 300, 500 and 700g/m2. The NOx removal efficiency of surface spray on fresh concrete due to all experimental conditions, on the other hand, which was very low within 10%. CONCLUSIONS : It was known that the $TiO_2$ penetration method as surface spray on hardened concrete was a good alternative in order to remove the NOx gases for concrete road structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.655-668
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• 1994

Conventional deodorization filters using soil and compost reach the capacity limitation of deodorization in short period, because its removal mechanism primarily depends on adsorption. Therefore, in this study the experiment was performed on the removal of ammonia which is a strong inorganic malodor, frequently emitted from night soil treatment plants and sewage treatment plants, by seeding activated sludges on the bio-peat containing higher organic contents, water conservation capacity, permeability and lower pressure drop. As a result, in raw peat filter natural ammonia outlet was observed in consequence of pH increase resulted from ammonia ionizing in liquid phase. Ammonia removal mechanism primarily depended on the adsorption onto the anion colloidal substances in peat. In peat bio-filter, theoretical ammonium salts ratio was higher than that of raw peat, resulted from slight pH increase by microorganism activity, however, the experimetal value of ammonia-nitrogen accumulated in bio-peat was lower than that of raw peat because of nitrification by nitrifying bacteria. In the initial reaction period, adsorption was predominant in the ammonia removal mechanism, but nitrification was conspicuous after the middle period. Mass balance of nitrogen was established using experimental data of input $NH_3$ loading, output $NH_3$ loading, $NH_4{^+}$-N, $NO_x$-N, and Org-N. The critical time of unsteady state, which is the maximum activating point of microorganism in bio-filter, was determined using experimental data, and the ammonia adsorption curve was computed using regression analysis. On the basis of the results obtained by above analysis, the delay days for the saturation of adsoption capacity in peat bio-filter was calculated.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.659-669
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• 2008

Two sets of four parallel activated sludge reactors (ASRs) maintaining an MLSS of 3000 mg/L were operated to investigate the effect of DO, HRTs and bio-contact media (BCM) packing ratios on the removal efficiency of organic matters and nitrogen. Packing ratios of BCM to BCM-ASR systems 1, 2, 3, and 4 were 0% (suspended growth only), 10%, 15% and 20%, respectively. All systems were operated at an HRT of 4 hr, 6 hr, and 8 hr, respectively; DO concentration was maintained 0.5~1.0 mg/L and 1.5~2.0 mg/L for each HRT condition. In terms of TSS, TCODcr and SCODcr removal efficiency, all systems had a similar level of the removal efficiency under varied HRTs, and DO. But organic removal efficiency of systems with BCM was approximately 3~5% higher than systems without BCM at the same HRT and the DO. About the nitrification efficiency, with high DO (1.5~2.0 mg/L), as HRT (4 hr, 6 hr, 8 hr) or BCM packing ratio increased, the slight increment of nitrification efficiency was observed. However, under the low DO (0.5~1.0 mg/L), increase of BCM packing ratio and HRT resulted in large increase of the nitrification efficiency. At the same HRT and BCM packing ratio, the nitrification efficiency increased greatly with up to 15% as DO increased. When the HRT increased from 4hr to 8hr, the denitrification efficiency slightly increased by 5~10% only, under all DO conditions. Systems with BCM had higher denitrification efficiency, ranged 62.7~91.1% than systems without BCM showed 32.1~65.6%. And the increase in BCM packing ratio from 10% to 20% resulted in about 14~16% denitrification efficiency increment. BCM packing ratio showed great effect on the denitrification. The increase of the DO (from 0.5~1.0 mg/L to 1.5~2.0 mg/L) at the same HRT and BCM packing ratio resulted in slight decrease of denitrification efficiency with up to 7% for systems with BCM. But for systems without BCM, the denitrification efficiency decreased with up to 28%. In all system, the denitrification efficiency had more influence on the TN removal efficiency than nitrification efficiency. So, BCM packing ratio (0%, 10%, 15%, 20%) has greater effect on the TN removal than HRT and DO. The TN removal efficiency increased as packing ratio of BCM increased with up to 45%. As a result, the highest TN removal efficiency was observed 73.7% at the condition showed the highest denitrification efficiency that DO of 0.5~1.0 mg/L, an HRT of 8 hr, and 20% of BCM packing ratio was maintained.

• Tuberculosis and Respiratory Diseases
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• v.61 no.4
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• pp.347-355
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• 2006

Background: Pneumonia is the most common cause of death among infectious diseases with community-acquired pneumonia being the sixth leading cause of death in the USA. In Korea, several studies have evaluated the prognosis of community-acquired pneumonia with a limited number of patients and risk factors. This study, evaluated all the possible risk factors (including the pneumonia severity index; PSI) in for the community-acquired pneumonia patients admitted to a referral hospital. Methods: The medical records of patients admitted to the Chung-Aug University Yongsan Hospital between January 2002 and January 2005 for community-acquired pneumonia were reviewed retrospectively. The demographic data, comorbidity, radiographic findings and laboratory results which might influence the prognosis of pneumonia were analyzed. Results: Among 179 patients admitted for community-acquired pneumonia, 29 patients died (mortality 16%). The risk factors for mortality in the comorbidity category were congestive heart failure and a myocardial infarction. The laboratory data, showed that albumin, LDH, total cholesterol, HDL, PT, aPTT, hemoglobin and blood urea nitrogen (BUN) were related to the prognosis. For the pneumonia severity index, the mortality rate increased in a step-wise manner from class I through class V. Conclusions: Comorbidities such as congestive heart failure and myocardial infarction as well as the albumin, LDH, total cholesterol, HDL cholestreol, prothrombin time, activated partial thrombotin time, hemoglobin and blood urea nitrogen(BUN) are important risk factors for mortality in patients with community-acquired pneumonia. PSI is a valuable index for evaluating the prognosis of community-acquired pneumonia.

• Journal of Microbiology and Biotechnology
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• v.17 no.8
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• pp.1254-1261
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• 2007

In the present study, we have constructed a bioluminescent bioreporter for the assessment of nitrate/nitrite bioavailability in wastewater. Specifically, an approximately 500-bp DNA fragment containing a nitrate/nitrite-activated nasR-like promoter (regulating expression of genes encoding nitrite reductase in the genus Klebsiella) was fused upstream of the Vibrio fischeri luxCDABE gene cassette in a modified mini-Tn5 vector. Characterization of this strain, designated W6-1, yielded dose-dependent increased bioluminescence coincident with increased nitrate, nitrite, and ammonium added to the growth medium from 1 to 11 ppm. Bioluminescence in response to nitrogen species addition was light dependent up to 10, 7, and 8 ppm with nitrate, nitrite, and ammonium, respectively. This response was linear in the range from 1 to 8 ppm for nitrate ($R^2=0.98$), 1 to 6 ppm for nitrite ($R^2=0.99$), and 1 to 7 ppm for ammonium ($R^2=0.99$). A significant bioluminescent response was also recorded when strain W6-1 was incubated with slurries from aged, nitrate/nitrite contaminated wastewater. Thus, bioreporter strain W6-1 can be used to elucidate factors that constrain the use of nitrate/nitrite in wastewaters.

• Korean Journal of Microbiology
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• v.21 no.2
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• pp.51-60
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• 1983

Cultural characteristics of Strptomyces griseolus isolated from the soil were investigated. This strain was disclosed to utilize D-xylose, and D-glactose in preference order as a carbon source with the formation of glucose isomerase. The addition of sweet potato starch also proved effective promoting the total enzyme activity measured at 29% higher than the control. Corn cob, one of waste agricultural resources, was hydrolyzed in 2~3% $H_2SO_4$ solution at $100^{\circ}C$, 3~5 hours to produce a xylose syrup which gave rise to the recovery of 19.9% in a batch system and 28.2% in a repeated system. By the addition of both 2% of xylose syrup(Be'28) prepared by and us 65% of corn steep liquor (total nitrogen 1.2%), enzyme induction was maximized. The enzyme activity was stimulated by the xylose and the cell growth by the C.S.L. Also, remarkable increase of enzyme activity was noticed by the addition of protein acid hydrolysate 86.2% higher than the control. $QO_2$ of the biomass cultured in 30L capacity jarfermentor recorded low oxygen requirement of 251.2 1/hr. Maximum activity of glucose isomerase was observed noted at the 9th hour after inoculation which is 2 hours faster than the stationery was observed noted at the 9th hour after inoculation which is 2 hours faster than the stationery phase of the biomass growth. Glucose isomerase from the strain was activated by adding the $Co^{++}\;and\;Mg^{++}$ with optimum temperature of $73^{\circ}C$ and pH of 7.2. Conversion ratio of 60% glucose to frutose was 42.5% after 70 hours reaction.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.3
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• pp.101-107
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• 1997

Phellinus linteus was artificially cultivated in kangwon province in Korea. The air-dried phellinus linteus was frozen in liquid nitrogen tank and powdered in jar. 10g of the powder was extracted with each 200g of ethanol, methanol, distilled water and 1,3-butylene glycol/distilled water 4 hours under refluxing and then the liquidextract was concentrated under reduced pressure. As a result of analysis by high performance liquid chromatography and thin layer chromarography, many kinds of sugar and flavonoids were detected. Also we knew that phellinus linteus' extract had a strong UV-ray absorption. In the efficacy test for applying to cosmetics, free radical scavenging effect was confirmed. As a result, 2% of sample was the most potent inhibitory effect and the free radical savenging activity, was 0.31%. This is more effective than any other meterial. In the test of antioxidative activity against lipid autoxidation, phellinus linteus' extract had a good effect by 46% while vitamine E was 42.3%. The immunological activity of phellinus linteus was showed through the activation of macrophage cell. Actually, phellinus linteus activated macrophage function of 1.1-1.8 times including nitrite production compared to control. The whitening effect of phellinus linteus was showed through the inhibition of tyrosinase activity, melanin biosynthesis of S. bikiniensis and B-16 melanoma cells. Phellinus linteus' extract was showed strong mushroom tyrosinase inhibitory activity with IC50 value of 0.5% and inhibited melanin biosynthesis with 28mm inhibition zone at 0.005%/paper disc in S. bikinniensis, a bacterium used as an indicator organism in this work. Also it inhibited melanin biosynthesis in B-16 melanoma cells with a minimum inhibitory concentration of 0.134%.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.110-119
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• 2004

The combination of biological and physical/chemical technologies is a promising technique to reduce highly concentrated pollutants in livestock wastewater. It is suggested to treat livestock wastewater efficiently as follows: firstly, biodegradable organic matters, nitrogen and some of phosphorus should be removed by a biological treatment process and then residual non-biodegradable organic matters, color and phosphorus be eliminated by physicochemical technologies. In this study, therefore, the integrations of chemical coagulation, activated carbon adsorption, Fenton oxidation and ozonation were evaluated to provide appropriate post-treatment processes for biologically pre-treated livestock wastewater. After chemical coagulation followed by ozonation or Fenton oxidation process, the quality of treated wastewater could meet the discharge limit in Korea. However, a yellowish brown color still remained in the treated wastewater after a single method such as coagulation and Fenton oxidation was applied. The ozonation was found to be the most effective technology for the decolorization. Neither simple biological nor physicochemical treatment provides adequate decolorization and sufficient depletion of organics in livestock wastewater so far. Consequently, the integration of Fenton oxidation and ozonation with a biological treatment process is recommended to treat livestock wastewater in terms of removal efficiency.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.93-101
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• 2006

This research makes a new attempt to apply the activated seawater by electrolysis in the development of two-stage wet scrubber system to control the exhaust gas of large marine diesel engines. First, with using only seawater that is naturally alkaline (pH typically around 8.1). the $SO_2\;and\;SO_3$ are absorbed by relatively high solubility compared to other components of exhaust pollutants, and PM (Particulate Matter) is removed through direct contact with sprayed seawater droplets. Besides, the electrolyzed alkaline seawater by electrolysis, which contains mainly NaOH together with alkali metal ions $(i.e.\;Na^+,\;Mg^{2+},\;Ca^{2+})$, is used as the absorption medium of NOx and $CO_2$. Especially, to increase NOx absorption rate into the alkaline seawater. nitric oxide (NO) is adequately oxidized to nitrogen dioxide $(NO_2)$ in the acidic seawater, which means both volume fractions are adjusted to identical proportion. The results found that the strong acidic seawater was a valid oxidizer from NO to $NO_2$ and the strong alkaline seawater was effective in $CO_2$ absorption In the scrubber test, the SOx reduction of nearly $100\%$ could be achieved and also led to a sufficientPM reduction. Hence, the author believes that applying seawater and its electrolyte would bring the marine air pollution control system to an economical measure. Additionally it is well known that NOx and SOx concentration has a considerable influence on the $N_2O$ emission of green house gas. Although the $N_2O$ concentration exhausted from diesel engines is not as high, the green house gas effect is around 300 times greater than an equivalent volume of $CO_2$. Therefore, we investigated the $N_2O$ removal efficiency with using the electrolyzed seawater too. Finally this research would also plan to treat the effluent by applying electro-dialysis and electro-flotation technique s in the future.

• Journal of Environmental Health Sciences
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• v.30 no.5 s.81
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• pp.481-486
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• 2004

Vehicle occupant exposure to air pollutants has been a subject of concern in recent years because of higher levels of air pollutants inside gasoline or diesel-using vehicle, comparing to the surrounding atmosphere. Contrary to previous studies, fuel of vehicles operated in this study was liquefied petroleum gas (LPG). This study examined the potential exposure and removal efficiency of selected volatile organic compounds (VOCs), nitrogen dioxide ($NO_2$) and respirable suspended particle (RSP) by commercial air cleaning device inside vehicle under different ventilation conditions. Vehicle concentrations inside of benzene, toluene, m,p-xylene, $NO_2$ and RSP were lower under the low ventilation condition. This was indicated that outdoor air pollutants could affect the vehicle air quality inside in case metropolitan cities such as Daegu. The urban vehicle concentrations inside of benzene, toluene, m,p-xylene, $NO_2$ and RSP with air cleaning device were higher than those without air cleaning device. This means that the use of air cleaning device equipped with activated carbon filter, which was used in this study, in the interior of vehicles could be expected to reduce the vehicle occupants exposure to air pollutants effectively. In batch type reactor of laboratory scale, removal efficiencies of air cleaning device used were $97.0\%,\;95.7\%,\;94.6\%\;and\;85.5\%$ respectively in benzene, toluene, m,p-xylene and $NO_2$.