• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1141-1146
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• 2010

Isolated the heterotrophic aerobic bacteria in sandfiltered water on NA and TSBA solid medium, selected 8 dominant species and identified by Sherlock System. Each samples are irradiated 0, 5, 16, 40 and $60\;mJ/cm^2$ using on CBD (Collimated Beam Device) Medium Pressure UV lamp after these identified bacterium did liquid culture how to make $10^6{\sim}10^7\;cells/mL$ suspended in dilution water. Then cultured bacteria are estimated inactivation rate on plate media. Identified Gram positive group are Bacillus Subtilus, Bacillus megaterium, Rhodococcus erythropolis and Microbacterium laevaniformans; Gram negative group are Pseudomonas vesicularis, Pseudomonas pseudoflava, Alcaligenes paradoxus and Zooglea ramigera. These isolation of bacterium are more stronger reference strain and high resistance of MP UV irradiation, Besides Gram negative bacterium are more sensitive Gram positive bacterium on MP UV dose. Now we are estimating to $60{\sim}100\;mJ/cm^2$ MP UV dose for efficient disinfection in water treatment plant.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.5
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• pp.547-555
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• 2009

The objectives of this research were focused on the effects of various operating parameters on nitrous oxide emission such as C/N ratio, ammonia concentration and HRT in the hybrid and suspension reactors. With the decreasing of C/N ratios, $N_2O$ emission rates in the both processes were increased because organic carbon source for denitrification was depleted. In case of biofilm reactor operated using medium, $N_2O$ release from the nitrification was not affected by the variation of ammonia concentration. But in the suspension reactor, $N_2O$ production from the nitrification was rapidly increased with the increase of ammonia. Nitrite accumulation caused by undesirable nitrification conditions could be a important reason for the increase in the $N_2O$ production from the aerobic reactor. And rapid increase in $N_2O$ production was reflected by the decrease of HRT, similar to the results observed in the results of ammonia loading changes. So it could be said that it is very important to put in consideration both its optimum conditions for wastewater treatment efficiency and suitable conditions for $N_2O$ diminish, simultaneously, in order to development an eco-friendly and advanced wastewater treatment, especially in BNR process.

• Food Science and Preservation
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• v.10 no.1
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• pp.37-40
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• 2003

Coptis chinensis extract and grapefruit seed extract, natural antimicrobial substances, were applied to the dipping treatment of strawberry and incorporated in the packaging films. Strawberry was steeped in the extract solutions of 50 ppm concentration and packed with the low density polyethylene(LDPE) films incorporated with 1% extracts. During the storage at 5$^{\circ}C$, the qualities of microbial counts, awぶy ratio, texture and chemical attributes were measured for the pretreated strawberry. The LDPE films incorporated with the extracts retarded the growth of aerobic bacteria, lactic acid bacteria and yeast that had been contaminated before the pretreatment, significantly lowed the decay ratio, and gave better retention of textural firmness. The chemical and physical qualities of strawberry were not affected by the packaging films. When strawberry was steeped in the extract solutions, the effects of the packaging film incorporated with the extracts on the qualities of strawberry were accelerated.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.897-905
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• 2019

To compare the composting characteristics of food waste supplemented with various bulking agents, aerated composting was performed by mixing sawdust, ginkgo leaves, insect feces, and mushroom waste at ratios of 6 : 4 (w/w). The initial temperatures (day after treatment [DAT] 3) of the sawdust, ginkgo leaves, insect feces and the mushroom waste mixtures were 39, 58, 65, and 51℃, respectively. The DAT 3 temperature was the highest in the food waste-insect feces mixture (65℃) and the lowest in the sawdust one (39℃). However, the insect feces treatment was terminated at DAT 21 because of a high water content (70.92%). The water content (DAT 56) of the composted food waste supplemented with sawdust, mushroom waste, and ginkgo leaves stood at 51.28, 39.81, and 44.92%, respectively. Therefore, the fully mature composts satisfied the water content requirement of less than 55% as recommended in the fertilizer standards of the RDA of Korea. The results of the CoMMe-101, Solvita and seed germination index methods indicate that the mushroom waste and ginkgo leaves treatments matured relatively quicker than that of the sawdust one. Based on the above observations, it is concluded that the mushroom waste and ginkgo leaves are more effective bulking agents compared to sawdust and as such, are recommended as suitable replacements for sawdust in food waste composting.

• Journal of Environmental Science International
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• v.25 no.3
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• pp.439-446
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• 2016

Domestic sewerage treatment plant is operated by activated sludge method and its modified method by using microorganism. In most cases, a method of using microorganism is directly controlled by the operator based on individual judgment through factors of DO, pH and ORP. In addition, under aerobic condition in bioreactor, energy consumption including excessive air injection is learned to be somewhat plenty. In order to solve this problem, in most of the process, improvement of internal recycling and activated environmental factor of microorganism were researched extensively. However, as factors are changed depending on various conditions, it is not sufficient as an indicator of judgment. As such, a research on operation of bioreactor that measures metabolic change in short time by directly measuring activated condition of microorganism using NADH fluorometer is required in reality.It is considered that the method like this could supplement problem of energy consumption being occurred in the existing treatment method and operational optimization of bioreactor would be enabled by controlling optimal air volume. Therefore, in this study, in order to obtain optimal operational indicator of bioreactor, proper air volume control test was performed and through batch test and site evaluation, possibility of NADH sensor being utilized as operational control indicator of bioreactor is intended to be analyzed. In order to compare with measured value, DO, ORP that are operational control indicator of existing bioreactor were used. As MLSS concentration was increased through batch test, NADH value was increased and site evaluation also showed similar tendency to batch test. Resultantly, it could be confirmed that changing level of NADH fluorometer was a sensor that could measure bioreactor condition effectively and optimized scale of bioreactor is considered to be utilized.

• Clean Technology
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• v.9 no.1
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• pp.23-28
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• 2003

The generation of food waste in Korea amounts to 4.10 million per year, which corresponds to 820,000 dry ton of organic waste. This has been used traditionally as animal feed or soil conditioner, but its efficacy has remained doubtful in recent years. In this study as an alternative we considered methane production by anaerobic treatment, which has an advantage of 200 million US dollars over aerobic methods. The production of methane amounts to $4.40{\times}10^8m^3$, 3.43% of $1.28{\times}10^8m^3$, total natural gas used in Korea. Furthermore the methane from household kitchen food waste amounts to 28.9% of the total gas used in the kitchen.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.735-741
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• 2013

Effects of cold plasma treatment (CPT) against Salmonella Typhimurium inoculated on cabbage and lettuce, naturally occurring bacteria in black pepper powder and red pepper powder, and Bacillus cereus inoculated onto red pepper powder were investigated. The numbers of S. Typhimurium on cabbage and lettuce were reduced by $1.5{\pm}0.2CFU/cm^2$ (900W, 5 min) and $1.1{\pm}0.1$ log $CFU/cm^2$ (900W, 10 min), respectively. The numbers of naturally occurring aerobic bacteria in both black pepper powder and red pepper powder were reduced by $2.3{\pm}0.3$ and $0.6{\pm}0.2$ log CFU/g, respectively. The numbers of B. cereus vegetative cells on red pepper powder were reduced by $1.5{\pm}0.1$ log CFU/g, but the numbers of spores remained unchanged. The inhibition of S. Typhimurium on cabbage was adequately described by Fermi's model and the Weibull model. The predicted optimum treatment power and time for S. Typhimurium inoculated onto cabbage were 746 W and 6.8 min, respectively. Our results indicate that CPT represents a useful method for microbial decontamination of vegetables and spices.

• Journal of Environmental Health Sciences
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• v.18 no.2
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• pp.67-74
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• 1992

The lab-scale biological A$_{2}$O system was applied from treating piggery wastewater highly polluted organic material which nitrogen and phosphorous are much contained relatively in conversion with other wastewater. The objective of this study was to investigate the effect of variance parameters on the treatability of this system according to operation conditions. An obtained experimental data were analysed by using principal component analysis (PCA) method. The results are summarized as follows: 1. From Varimax rotated factor loading in raw wastewater, variance of factor 1 was 36.8% and cumulative percentage of variance from factor 1 to factor 4 was 81.5% and of these was related to BOD, TKN and BOD loading. 2. In anaerobic process, variance of factor 1 was 33.5% and cumulative percentage of variance from factor I to factor 4 was 81.8% and of these was related to PO$_{4}$-P, BOD, DO and Temperature. 3. In anoxic process, variance of factor 1 was 30.1% and cumulative percentage of variance from factor i to factor 4 was 84.3% and of these was related to pH, DO, TKN and temperature. 4. In aerobic process, variance of factor 1 was 43.8% and cumulative percentage of variance from factor 1 to factor 4 was 81.5% and of these was highly related to DO, PO$_{4}$-P and BOD. 5. It was better to be operated below 0.30 kg/kg$\cdot$day F/M ratio to keep over 90% of BOD and SS, 80% of TKN, and 60% of PO$_{4}$-P in treatment efficiencies. 6. Treatment efficiencies was over 93% of BOD and SS, 81% of TKN and 60% of PO$_{4}$-P at over 20$^{\circ}$C, respectively.

• Food Science of Animal Resources
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• v.38 no.3
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• pp.487-497
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• 2018

Controlling of microorganisms in the industrial process is important for production and distribution of hatching and table eggs. In the previous study, we reported that chlorine dioxide ($ClO_2$) gas of a proper concentration and humidity can significantly reduce the load of Salmonella spp. on eggshells. In this study, we compared microbial reduction efficacy on egg's surface using hatching eggs and table eggs, internal quality of table eggs, and hatchability after both the conventional method (washing and UV expose, fumigation with formalin) and $ClO_2$ gas disinfection. Application of 40 ppm $ClO_2$ gas to the table and hatching eggs, respectively, reduced the aerobic plate count (APC) with no statistical difference compared with the conventional methods. Additionally, we didn't observed that any significant difference in albumin height, Haugh unit (HU), and yolk color, this result confirms that 40 ppm $ClO_2$ had no effect on the internal quality of the table eggs, when comparing with the UV treatment method. The hatchability of hatching eggs was not statistical different between formaldehyde fumigation and 80 ppm $ClO_2$ gas treatment, though the value was decreased at high concentration of 160 ppm $ClO_2$ gas. From these results, we recommend that $ClO_2$ gas can be used as a safe disinfectant to effectively control egg surface microorganisms without affecting egg quality.

• Food Science of Animal Resources
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• v.36 no.5
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• pp.601-611
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• 2016

The objective of this study was to evaluate effects of Gaeddongssuk powder (GP) on quality characteristics and shelf stability of emulsion sausages during storage. Proximate composition properties showed no significant differences in all treatment (p>0.05). Control showed the highest cooking loss while the treatment with GP showed decreased cooking loss depending on increasing GP content (p<0.05). Apparent viscosity of batter was increased as the amount of GP increased, whereas hardness of emulsion sausages was decreased with increasing GP level. In sensory evaluation, emulsion sausage with 0.1% GP resulted in the highest score in overall acceptability. The pH values of all treatments decreased at the early storage stage, followed by gradual increase. The lightness and redness of treatments were decreased when the level of GP was increased. However, the yellowness of sausages with GP were higher than that of control (p<0.05). The addition of GP inhibited lipid oxidation of emulsion sausages during storage depending on its level. The aerobic bacteria population and VBN was unaffected by addition of GP during the storage (p>0.05). Therefore, Gaeddongssuk powder up to 0.1% has a potential as a natural antioxidant for meat products because it can inhibit lipid oxidation of sausages without decreasing their sensory properties.