• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.69-75
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• 2006

Improper disposal of petroleum and spills from underground storage tanks have created large areas with highly toxic contamination of the soil and groundwater. Methyl tert-butyl ether (MTBE) is widely used as a fuel additive because of its advantageous properties of increasing the octane value and reducing carbon monoxide and hydrocarbon exhausts. However, MTBE is categorized as a possible human carcinogen. This research investigated the Modified Photo-Fenton system which is based on the Modified Fenton reaction and UV light irradiation. The Modified Fenton reaction is effective for MTBE degradation near a neutral pH, using the ferric ion complex composed of a ferric ion and environmentally friendly organic chelating agents. This research was intended to treat high concentrations of MTBE; thus, 1,000 mg/L MTBE was chosen. The objectives of this research are to find the optimal reaction conditions and to elucidate the kinetic and mechanism of MTBE degradation by the Modified Photo-Fenton reaction. Based on the results of experiments, citrate was chosen among eight chelating agents as the candidate for the Modified Photo-Fenton reaction because it has a relatively higher final pH and MTBE removal efficiency than the others, and it has a relatively low toxicity and is rapidly biodegradable. MTBE degradation was found to follow pseudo-first-order kinetics. Under the optimum conditions, [$Fe^{3+}$] : [Citrate] = 1 mM: 4 mM, 3% $H_2O_2$, 17.4 kWh/L UV dose, and initial pH 6.0, the 1000 ppm MTBE was degraded by 86.75% within 6 hours and 99.99% within 16 hours. The final pH value was 6.02. The degradation mechanism of MTBE by the Modified Photo-Fenton Reaction included two diverse pathways and tert-butyl formate (TBF) was identified to be the major degradation intermediate. Attributed to the high solubility, stability, and reactivity of the ferric-citrate complexes in the near neutral condition, this Modified Photo-Fenton reaction is a promising treatment process for high concentrations of MTBE under or near a neutral pH.

• Korean Journal of Ecology and Environment
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• v.41 no.spc
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• pp.50-60
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• 2008

We performed the experiment to evaluate the effect of different DO concentrations (0.5, 4.5 and 9.0 $mgO_2L^{-1}$) and water depths (20, 50 and 80 cm) on the filtering rate, mortality, and pseudifeces production of Unio douglasiae against the cyanobacterial bloom (mainly Microcystis aeruginosa). A solitary-living bivalve U. douglasiae was collected in the upstream region of the North Han River (Korea). The harvested mussels were carefully transferred to the laboratory artificial management system, which was controlled temperature $(18{\pm}2^{\circ}C)$, flow rate (10L $h^{-1}$), food $(Chlorella^{TM})$, sediment (pebble and clay), light intensity (ca. $20{\mu}mol$ photons), and photocycle (12 L : 12 D). In the field observation, the mussel mortality was significantly correlated with water temperature, pH and DO concentration (P<0.05). The mortality was decreased with water depth; 65, 90, 80% of mortality at 20, 50, 80 cm water-depth, respectively. Filtering rate (FR) showed the highest value at 50 cm water depth, and thereby the concentration of chlorophyll-${\alpha}$ decreased continuously by 94% of the control at the end of the experiment. In contrast, FR decreased by 34% of the initial concentration at 20 cm water depth. Over the given water-depth range, the mussel FR ranged from $0.15{\sim}0.20L\;gAFDW^{-1}hr^{-1}$ during the 18hrs of experiment, and thereafter, they appeared to be approximately 0.11, 0.26 and 0.30 L $gAFDW^{-1}hr^{-1}$ at 20, 50 and 80cm water depth, respectively. FR was highest with the value of 0.46L $gAFDW^{-1}hr^{-1}\;at\;0.5mgO_2 L^{-1}$ at the early stage of the experiment, while it increased with DO concentration. Maximum pseudofaeces production was 11.2 mg $gAFDW^{-1}hr^{-1}\;at\;9.0mgO_2L^{-1}$. Our results conclude that U. douglasiae has a potential to enhance water quality in eutrophic lake by removing dominant cyanobacteria, but their effects vary with environmental parameters and the water depth at which they are located.

• Journal of Animal Science and Technology
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• v.50 no.4
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• pp.485-498
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• 2008

This study was conducted to evaluate effects of dietary rare earth on growth performance, blood immune- related cell population, meat quality and fecal odor emitting gases in finishing pigs. The total of sixty four (Landrace×Yorkshire×Duroc) pigs(65.42±1.16kg in average initial body weight) were used for feeding trial during 10 weeks of experimental period. Dietary treatments included 1) NC(antibiotic free diet), 2) PC (NC diet+6 weeks 44ppm of tylosin/ 4 weeks 22ppm of tylosin) 3) RE1 (NC diet + 100ppm of RE), 4) RE2 (NC diet+200ppm of RE). There were four dietary treatments with four replicate pens per treatment and four pigs per pen. During the overall periods, there were no significant differences in ADG(Average daily gain), ADFI (Average daily feed intake) and gain/feed ratio among treatments(P>0.05). Dry matter and nitrogen digestibility were higher in RE2 treatment group than other groups(P<0.05). Also, energy digestibility was higher in RE2 treatment group than PC and RE1 treatment groups(P<0.05). At the 6th week WBC(white blood cell) was significantly increased(P<0.05) in RE1 treatment group than NC and RE2 treatment groups. L* value of M. logissimus dorsi muscle color was significantly increased(P<0.05) in rare earth supplemented groups compared to NC treatment group(P<0.05). However, a* value was lower in RE1 treatment group than PC treatment group (P<0.05). In fatty acid composition of Intramuscular fat, total MUFA was significantly higher in RE2 treatment group than other groups(P<0.05). Also, total UFA was significantly increased in RE2 treatment group compared with NC and PC treatment groups(P<0.05). In fatty acid composition of back fats, total SFA of rare earth supplemented groups were lower than in PC treatment group(P<0.05). UFA:SFA ratio was significantly higher in rare earth supplemented groups than PC treatment group(P<0.05). In fecal odor emission, NH3 was significantly decreased(P<0.05) in rare earth supplemented groups compared to NC and PC treatment groups. In conclusion, the results of the experiment was affected by rare earth supplementation on digestibilities, meat quality, fatty acid and fecal odor emission gases in finishing pigs.

• Journal of The Korean Society of Grassland and Forage Science
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• v.13 no.1
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• pp.43-48
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• 1993

This experiment was carried out to determine the effects of application time of cattle slurry on grazing pasture on the grass growth, dry matter yield, nutritive value, animal preference, and efficiency of pasture utilization. Four different application times of slurry(right now after grazing, 5th day, 10th day, and 15th day after grazing), and a no-slurry(control) plot were designed, 1991∼1992. Annual application amount of slurry was 40 ㎥/ha, and slurry was applicated in spring(2 times), summer and autumn. Total NPK fertilizer applicated were same as 280, 200 and 240 kg/ha in all treatment, respectively. The pasture was grazed with growing beef cattle(initial body wt.; ca. 250 kg) at every 30∼35 cm of plant height. The grass height, dry matter yield, crude protein yield, and other nutritive value were not different among treatments. However, the animal preference and efficiency of pasture utilization showed significant difference by application time of slurry. The highest grazing preference (1: the worst∼9: the best). and utilization efficiency (0∼100%) were observed by application time of right now after grazing (7.8, 76%), which was same to control(7.8, 77%), and followed by 5th day after grazing(7.3, 74%) and l0th day after grazing(6.9, 71%). But the preference and pasture utilization were greatly decreased at application time of cattle slurry of 15th day alter grazing(5.5, 60%). From the above results, the optimum application time of cattle slurry on grazing pasture to enhance animal preference, and efficiency of pasture utilization was within 5 days after grazing (less than 13.6 cm of plant height), and within 10 days after grazing (less than 18.5 cm of plant height) at least.

• Food Science of Animal Resources
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• v.26 no.2
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• pp.197-203
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• 2006

This study was conducted to investigate the effect of seleium (Se) and vitamin E supplementation on meat quality and shelf-life in finishing pigs. A total of eighty ($Landrace{\times}Yorkshire{\times}Duroc$) pigs (74.74 initial BW) were randomly allocated into five treatments with four replications and fed for six weeks. Dietary treatments included 1) CON (basal diet), 2) ISE2 (basal diet+0.2 ppm inorganic Se+100 ppm vitamin E), 3) ISE4 (basal diet+0.4 ppm inorganic Se+100 ppm vitamin E), 4) OSE2 (basal diet+0.2 ppm organic Se+100 ppm vitamin E) and 5) OSE4 (basal diet+0.4 ppm organic Se+100 ppm vitamin E). Cooking loss was decreased in treatment of ISE4 as compared with treatment of CON (p<0.05). Crude fat (%) of OSE2 was higher than those of others (p<0.05). Redness ($a^*$- value) of M. longissimus dorsi was increased in treatment of OSE2 as compared with other treatments after 100 of storage (p<0.05). Thiobarbituric acid reactive substances (TBARS) was decreased in treatment of OSE4 compared with treatments of CON and ISE2 after 10d of storage (p<0.05). In conclusion, Se and vitamin E combination did not significantly affect cooking loss,$a^*$- value and TBARS except for cases.

• The Korean Journal of Food And Nutrition
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• v.14 no.1
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• pp.34-39
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• 2001

The purpose of this study was to examine physical properties of the addition of green tea powder on bread flour and dough rheology of white pan bread. Three levels(0.1, 0.5 and 1.0% ) of each green tea powder with bread flour were tested for their effects in dough mixing using rapid disco analyzer, alveogram and farinogram. Addition of green tea powder tended to reduce initial pasting temperature and increase peak viscosity, break down and set back. L(extensibility) and G(swelling index) value in alveogram showed decrement with increasing green tea powder. These meant that the volume of white pan bread would show same tendency. The use of green tea powder increased consistency and water absorption of the bread flour but decreased development time, salability and degree of softening on farinogram. White pan bread with green tea powder had higher value of hardness and springness than without it. Sensory evaluation determined that the white pan bread with 0.5% green tea powder had the highest score.

• Food Science of Animal Resources
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• v.25 no.1
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• pp.20-25
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• 2005

This study was conducted to evaluate the effects of Zizyphus vulgaris supplementation on growth performance, blood cortisol and meat quality characteristics in finishing pigs. The total of thirty-six [Duroc${\times}$Yorkshir${\times}$Landrace] pigs ($91{\pm}2.11$ kg average initial body weight) were used in a 30-days assay. Dietary treatments included 1) CON (basal diet), 2) T1 (basal diet for 15 days and 0.1 % Zizyphus vulgaris for 15 days) and 3) T2 (0.1 % Zizyphus vulgaris for 30 days). The ADG (Average daily gain), ADFI (Average daily feed intake) and ADG/ADFI during the feeding period were not significantly differences among the treatments (p>0.05). Backfat thickness of pigs fed CON was higher than those of T1 and T2 (p<0.05). The appearance rate of A or B carcass grade was in T1 (74%) and T2 (84%) was significantly higher than that in CON (58%) (p<0.05). Pigs fed Zizyphus vulgaris 0.1 % for 30 days tended to decrease on blood cortisol compared with pigs fed CON and T1. But, there was not significantly difference among the treatments (p>0.05). The Hunter's L/sup */ (lightness) value of loin in the pork fed CON was higher than that of loin in the pork fed T1 and T2 (p<0.05). After 7 days, the L/sup */ value of loin in the pigs fed T2 was higher increased than that of pigs fed T1 and CON (p<0.05). However, a/sup */ and b/sup */ values were not affected by dietary Zizyphus vulgaris (p>0.05). There were not found remarkable differences in sensory properties (marbling, firmness and color) among the treatments. The results from the present study suggest that Zizyphus vulgaris could be a effective feed additive to improve meat quality of pigs. However, further research is needed to investigate effects of carcass characteristics.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.4
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• pp.41-50
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• 2017

The design of proper agitation system is requisite in biological waste treatment and energy generation plant, which is affected by viscosity, impeller types, and power consumption. In the present work, hydrogen fermentation of food waste was conducted at various operational pHs (4.5~6.5) and substrate concentrations (10~50 g Carbo. COD/L), and the viscosity of fermented broth was analyzed. The $H_2$ yield significantly varied from 0.51 to $1.77mol\;H_2/mol\;hexose_{added}$ depending on the pH value, where the highest performance was achieved at pH 5.5. The viscosity gradually dropped with shear rate increase, indicating a shear thinning property. With the disintegration of carbohydrate, the viscosity dropped after fermentation, but it did not change depending on the operational pH. At the same pH level, the $H_2$ yield was not affected much, ranging $1.40{\sim}1.86mol\;H_2/mol\;hexose_{added}$ at 10~50 g Carbo. COD/L. The zero viscosity and infinite viscosity of fermented broth increased with substrate concentrations, from 10.4 to $346.2mPa{\cdot}s$, and from 1.7 to $5.3mPa{\cdot}s$, respectively. There was little difference in the viscosity value of fermented broth at 10 and 20 g Carbo. COD/L. As a result of designing the agitation intensity based on the experimental results, it is expected that the agitation intensity can be reduced during hydrogen fermentation. The initial and final agitation intensity of 30 g Carbo. COD/L in hydrogen fermentation were 26.0 and 10.0 rpm, respectively. As fermentation went on, the viscosity gradually decreased, indicating that the power consumption for agitation of food waste can be reduced.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.8
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• pp.554-563
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• 2013

The purpose of this study is to evaluate the possibility of nutrient release at up and downstream of Kangchun weir, upstream of Yuju and Ipo weir in Namhan River. For this survey, we measured basic characteristics of the sediments (water content, ignition loss, TOC, TP, SRP, TN, phosphorus fractionation) and conducted nutrients release experiments under both aerobic and anaerobic condition. The overlying water from the sediment-water column was analyzed for nutrients (i.e. TP, $PO_4$-P, TN, $NO_3$-N, $NH_3$-N) everyday for 18days. Result of soil texture experiment showed that sediments are Sand. SRP concentration before the release experiment was different with the value after the release experiment. According to this result, we can find that there were more activated release processes in anaerobic condition. $PO_4$-P increased from 1 to 8 days and remained at the maximum value (7~8 days) afterward. The rapidly increase of $PO_4$-P was observed from 1 to 2~3 days whereas the TP continuously increase from 1 to 18 days. The $PO_4$-P release rate calculated by up to 7~8 days data highly correlated with initial SRP concentration with $R^2$=0.8502. $NO_3$-N release rate appears constantly decreasing trend as -5.7~-3.08 $mg/m^2{\cdot}day$, otherwise the $NH_3$-N release rate, by-product of a organic matter decomposition using nitrate as electron acceptor, was 0.57~2.41 $mg/m^2{\cdot}day$. Substantial portion in TN can be induced by organic nitrogen which originated from the tributary passing through non-point pollutant source. Compared with other similar researches, phosphorus and nitrogen release rates obtained in this study can be considered as relatively low values. Since this study targeted the sediments accumulated by one time of flooding season, there are limitation to generalize theses results. Therefore, it is necessary to consistently monitor and investigate the accumulation of nutrients in the sediment for understanding the effect of weir construction on the overlying water quality.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.1
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• pp.41-51
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• 2012

We produced Hwanggiju (added 0.5~2.0% of ground Astragali Radix compared to starch contents) and investigated the physicochemical characteristics, DPPH free radical scavenging activities, polyphenol contents, and sensory evaluation. For all treatments, the initial pH was 3.9~4.1 and gradually decreased for 6 days from the 1st mashing day, and then rapidly increased to 4.67. As the fermentation proceeded, total acid contents increased in most of the treatments, reduced temporarily after the 2nd mashing time because of the addition of starch material and water, and then slightly rose again. There were little changes in pH and total acid contents followed by adding ground Astragali Radix (AR) to the fermentation periods. Amino acidities of all treatments showed patterns of which consistently rose as the fermentation proceeded and slightly reduced followed by increasing the addition rate of ground AR to the mashes. Soluble solid and alcohol contents also increased continuously and there were few differences among the treatments followed by adding to the ground AR rate. In color, there was no differences in L value, but a and b value showed significant differences by adding ground AR rate. In DPPH free radical scavenging activities, the control (no AR added) showed 53.6% and when grinded AR added, there were improving effects of the activities (0.52~6.9%). In polyphenol contents, the control was 1.05 mg/mL and the ground AR added treatments increased slightly. In the sensory evaluation, the control received a relatively high score ($5.0{\pm}1.0$), and the treatments which added 0.5% ground AR during the 2nd mashing time were also well received ($4.5{\pm}1.3$).