• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.4
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• pp.75-80
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• 2002

The sewage sludge with concentrated MLSS, ranging from 5967 to 8400mg/L was degraded by ultrasound. In this study, ultrasound treatment was used to investigate the behavior characterization of SBOD, sludge biodegradation, C/N ratio, TN, turbidity and sludge morphology. From the experimental results of C/N ratio change and TN removal, the optimal irradiation time was found to be 10 minutes. The results showed the relative index of sludge biodegradation(SBOD/TCOD) was enhanced to 0.76 from the initial value of 0.013 at the 5967mg/L MLSS, during the 60minutes treatment. Throughout this research, the results provide useful engineering reference data for reuse of sewage sludge using ultrasound.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.7
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• pp.523-529
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• 2011

This study has been performed to examine the influence of the size of particles on the stabilization in the aerobic stabilization equipment connected with MBT system. The biodegradable waste inside the reactor (60% of food waste, 25% of paper waste, 2% of wood waste and 5% of compost) has been charged in same composition. The degree of stabilization was compared and analyzed after charging with adjustment of particle size in 5 mm, 10 mm, 20 mm, 50 mm, 100 mm and state of no separation. The experiment revealed that highest temperature beyond $65^{\circ}C$ was shown in the particle size of less than 50 mm in change of temperature and the highest temperature was about $50^{\circ}C$ in reactor of 100 mm and no separation. The proportionality between generated quantity of $CO_2$ and particle size was not observed, even the highest in generated quantity was shown in over 100 mm. The weight changes based on wet and dry conditions in the reaction process showed the 30% and 46% of reduction in the smallest particle size of 5 mm and it showed the trend of the lower reduction rate at the bigger particle size. The water soluble $COD_{Cr}$ and TOC showed the reduction rate of 60% in reactor of particle size in 100 mm and no separation while the reduction rate comparing to the initial stage of reaction in the reactor of less than 50 mm was 80%. Such result derived the conclusion of acceleration in the decomposing stabilization of biodegradable material due to the decomposing rate of organic substance as the particle size of biodegradable waste gets smaller. It is concluded as necessary to react in adjustment under 50 mm of particle size as much as possible.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.3
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• pp.97-104
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• 2005

In this study, the change of water content, pH, and combustion weight on the decomposition of poly ester vinyl and high density poly ethylene were examined. The poly ester vinyl was degraded by microorganism in food wastes for 30 days, while high density poly ethylene vinyl was not degraded. Also, the poly ester vinyl was rapidly degraded after the 10 days of operation and its weight was decreased. In the combustion reaction between $300^{\circ}C$ and $600^{\circ}C$, complete combustion was performed. Due to the degradation of poly ester vinyl by microorganism in food waste, the pH was increased from 4.26 to 7.6. During of 60 days operation, poly ester vinyl was degraded over 90%.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.361-364
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• 2002

BAC (biological activated carbon) process is a combination of biodegradation and active carbon adsorption. Pre-ozonation of raw water increased in biodegradable organic fraction. This study is to investigate the enhancement of dissolved organic matter removals by pre-ozonation process combined with BAC process at a semi-pilot scale. By biodegradation improvement in pre-ozonation process. the charge of adsorption was reduced and the life of biological activated carbon is extended. And, 48 % of total DOC was remove in the upper compartment of BAC column. The removal of the nitrogen-ammonia shows a considerably high removal ratio with 75.9 %.

• KSBB Journal
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• v.8 no.3
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• pp.230-236
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• 1993

A Chitulose film was made by dissolving chitin and cellulose in a dimethylacetamide/LiCl solvent system This film was completely degraded in 20 days in soil and penetrated by soil microorganisms in 16-26 hours. A permeability analysis of the film showed that water permeability was in the range of 0-187.5 $1/m^2$/day, depending upon the ratio of chitin to cellulose and decreased with increasing a cellulose content in the Chitulose film The permeabilities of organic compounds, $Na^+$ and oxygen change with the composition of the Chitulose file The film was tested with a burned 2~3degree rat for exploring its use as artificial skin. The rat was completely cured within 31 days without inflammation.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.1
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• pp.75-86
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• 1994

Garbage composting was studied in a controlled batch reactor with the addition of cooked rice as a biodegradable carbon source to find the effect of C/N ratio control on composting. And composting of bulking agents such as sawdust and wheat straw were tested with the addition of ammonium sulfate as a nitrogen source. As expected, biodegradation of the garbage having low C/N ratio was improved to some extent when foreign carbon was added. But bulking agents used in this study exerted slightly biodegradable carbon potential, indicating that the estimation of the dose of additional carbon considering desirable C/N ratio was not reasonable when lignocellulosic bulking material was added to garbage. It was found that the optimum moisture content increased with sawdust addition meaning the C/N ratio increment. Considering the above results, it was suggested that 78g sawdust per 100g garbage should be mixed to make C/N ratio to 25 and moisture content to 56% for effective composting of the garbage studied in this paper.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.3
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• pp.207-215
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• 2023

This study was compared the soil environment and growth and yield of onion (Allium cepa L.) treated with non-mulching (NM) and mulching polyethylene film (PEF) and two biodegradable films (BFI and BFII) commonly used in farmhouses. Visual observation confirmed the degradation of BFI and BFII films after 150 days after tansplanting (DAT). BFII increased light penetration into the films and reduced the weight maintenace after 180 DAT, with a high decompostion at 30 days after soil tilling. Soil moisture contents much fluctuated between -14 kP and - 0 kPa in NM plots, increasing the minimum soil temperature of BFI plots. Mulching treatments decreased soil organic matter contents but did not subtantially increase soil mineral nutrients, soil bulk density, and number of bacteria compared to those of NM plots. Onion root growth was increased by PEF and BFI treatments at an early growth stage, 60 DAT, with the most remarkable stem extension observed for PEF and BFI treatments after 150 DAT. PEF and BFI treatments increased the bulb's diameter, length, weight, and lodging at 180 DAT. BFI treatments exhibited a high portion of the "very large" category producing with 55.3 tons ha^-1 based on the classification into bulb size, followed by PE (49.3 tons), NM (9.4 tons), and BFII treatments (2.7 tons) at 230 DAT.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.3
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• pp.41-52
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• 2014

In this study, to estimate the biodegradability of sewage discharged intermittently, field scale sampling and analysis was conducted and the results were obtained as follows. According to results of the biodegradability of sewage discharged intermittently, average concentration of TCODcr is 325.5mg/L and ratio of TCOD fraction resulted 100%. Also, average concentration of SCODcr resulted 135.9mg/L and ratio of TCOD fraction resulted 41.8%. Average concentration of Ss showed 74.1mg/L and ratio of TCOD fraction resulted 22.8%. Average concentration of $S_I$ was analyzed to be 61.8mg/L and ratio of TCOD fraction was calculated to 19.0%. Xs which is particulate matter was analyzed to show 27.8mg/L and ratio of TCOD fraction also showed 8.5%. Average concentration of $X_H$ is 103.4mg/L and ratio of TCOD fraction resulted 31.8%. Inert particulate matter showed that average concentration of $X_I$ is 58.5mg/L and ratio of TCOD fraction resulted 18.0%. Accordingly, dissolved biodegradable organic matter showed the ratio of 41.8%, and readily biodegradable matter among this showed 22.8%. Thus intermittent inflow is expected to have less effect with regards equalization by organic loading rate of influent.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.1
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• pp.49-54
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• 2012

Microbial changes in the characteristics of dissolved organic matter (DOM) and the subsequent effects on the conditional stability constants of copper were investigated using 14 day-incubations of Pony Lake fulvic acid (PLFA), Suwannee River fulvic acid (SRFA) and the mixtures of the humic substances and glucose. After incubation, dissolved organic carbon (DOC) concentrations were diminished, and specific UV absorbance values and DOC-normalized fluorescence intensities increased. The microbial changes were minimal for the samples contaning humic substances only whereas they were much pronounced for the mixtures with glucose. The extent of the changes increased with a higher content of glucose in the mixtures. The same trend was observed even for glucose solution. Our results suggest that labile organic moieties may be transformed into more chromophoric and humidified components by biodegradation. For the mixture samples, the copper binding stability constants did not change or even decreased after incubation. Therefore, microbially induced enrichment of the fulvic- and humic-like carbon structures in DOM appears to result in little change or the decrease of the copper binding coefficients.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.7
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• pp.479-484
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• 2013

This study was performed to examine the effect of copper on the biodegradability, nitrification, denitrification and oxygen uptake rate (OUR) using batch reactor and continuous flow stirred tank reactor (CSTR) of anaerobic/anoxic/oxic ($A_2/O$). The results of this study can be summarized as follows. In the case of the effect of copper on organic treatment, the bad effect initiated when it was above 4.5 mg/L copper with batch reactor and above 2.0 mg/L copper with CSTR. Concerning the case on nitrification and removal of nitrogen, it showed bad effect when copper was above 4.5 mg/L with batch reactor for nitrification and 1.0 mg/L with CSTR for the removal of nitrogen. The bad effect on the removal of phosphorus began when it was 4.5 mg/L copper with batch reactor and 2 mg/L copper with CSTR. In the case of OUR, it decreased as microbial activity was affected when copper concentration was above 1.5 mg/L in both case of batch reactor and CSTR.