• Microbiology and Biotechnology Letters
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• v.27 no.2
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• pp.107-112
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• 1999

A bacterium, which can utilize cyclohexanol as a sole source of carbon and energy, was isolated from sludge in sewage of Ulsan Industrial Complex for Petrochemicals, Korea and identified as Rhodococcus sp. TK6. The growth conditions of the bacteria were investigated in cyclohexanol containing media. The bacteria utilized cyclohexanol, cyclohexanone, cyclohexane-1,2=diol, cyclopentanol, cyclopentanone, and $\varepsilon$-caprolactone but not cyclohexane, cyclohexane-1,2-dione, and cyclooctanone. The bacteria were able to utilize alcohols such as ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-methyl-1-propanol, 3-methyl-1-butanol, 2-propanol, and 2-butanol as well as cyclohexanol, organic acids such as adipate, propionate, butyrate, valerate, n-caproate, and 6-hydroxycaproate, and aromatic compounds such as phenol, salicylate, p-hydroxbenzoate, and benzoate as a sole source of carbon and energy. Cyclohexanone as a degradation product of cyclohexanol by Rhodococcus sp. TK6 was determined with gas chromatography.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.534-538
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• 2004

Granulation characteristics have been studied with an aerobic sequencing batch reactor(SBR). Organic loading of 2.46kg COD/$m^3$/day followed by 4.14kg COD/$m^3$/day had been applied to the lab-scale SBR with a very short settling time during the operating cycle. The granulation proceeded to the diameter range of 3 to 5 mm with MLSS concentration of 12,000mg/L at 45th days of operation while COD removal efficiency remained almost consistent after the granule formation. It has been noticed that aerobic granulation under the higher loading with a very short settling time seemed to be due to the microbial selection of better flocculating species.

• Journal of Environmental Science International
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• v.12 no.10
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• pp.1095-1100
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• 2003

In this study, it was performed using submerged nonwoven bioreactor(SNBR) for removal of organic matter, nitrogen and phosphate under different aeration intervals(intermittent aeration). We applied the SNBR at the cheap nonwoven fiber module instead of the expensive membrane. The SUBR was mainly made up of an activated sludge reactor and a transverse flow nonwoven module, with an innovative configuration being in application between them. In case of sewage, the aeration conditions experimented consist of continuous aeration and 60min/60min, 120min/60min, 120min/120min of aeration/nonaeration time intervals, respectively. In case of landfill leachate, the intermittent aeration condition was 120min/120min at aeration/nonaeration. Consequently, a high COD removal rate (about 94%) was achieved in sewage and leachate. Although nutrient removal rate was relatively high without any additional chemicals.

• Proceedings of the Korean Environmental Health Society Conference
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• 2001.11a
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• pp.64-69
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• 2001

The present work provides a result from the preliminary experiment for hydrocyclone technology. In this work, local lake sediments and waste coal fly ash were used as test samples, prior to the application of hydrocyclone technology to the waste sludge thickening. A few cyclones based on the Rietema standard geometry were prepared. Chemical analysis of the sediments showed that more organic contaminants were in smaller particles. The experimental tests further showed that physical characteristics of particles, configuration of the cyclone and operation condition would affect the separation efficiency. The current results showed that small size cyclones might improve the separation and concentration of the lake sediments, and higher inlet velocity would increase the concentration rate of under flow and absolute concentration of sediment particles.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.6
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• pp.837-848
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• 2006

This paper presents the test results of biological aerated filtration(BAF) process to replace activated sludge process by enhancing treated effluent quality and reducing the costs. In BAF process both BOD and SS compounds in wastewater are degraded and removed by biological reaction and filtration. Upflow BAF with expanded polypropylene media and downflow BAF with ceramic media were used to investigate the effects of hydraulic and organic loads on effluent quality. As a result, in BAF processes which has different media, upflow BAF reactor shows 5% higher efficiency than downflow BAF and this phenomena caused by backwashing methods and operational conditions. The results of influence factors analyzed by Factor Analysis Method in BOD and SS treatment efficiency are the size of media, hight of media bed and type of media. The quantitative effects of media size are 5.73% in TBOD, 5.78% in SBOD and 7.65% in TSS, so we confirmed the main factor is media size.

• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.303-310
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• 2010

Recently distinguished AOP means technology resolving organic compounds in water to harmless compounds such as $CO_2$ and $H_2O$ by creating OH radical ($OH{\cdot}$) with more powerful oxidation than general oxidants. It has merits which the 2nd pollution is not caused since it uses solar energy, sludge doesn't take place, it can be applied to high-density waste water and it oxidizes non-biodegradable organic compounds more easily. The purpose of the study was to examine about removable characteristics of phenol which was a non-biodegradable organic matter with UV/$O_3$/Catalyst processes which is one out of AOP and to present applicability of photocatalyst and the optimum conditions of treatment. The study regarded initial phenol concentration, initial pH, photocatalyst amount and flow as its conditions. As the results, the test had the highest removable efficiency (92%) when initial phenol concentration was 100 mg/L, initial pH 7, photocatalyst amount 6L and flow 1.5 mg/min. The removable efficiency was increased as much as initial phenol concentration was increased, when initial pH was 7 (neutrality), photocatalyst amount was increased and flow was increased. It was checked that the optimum HRT was 12 hours. Therefore, phenol is enough removable with UV/$O_3$/Catalyst process and its prospect in the future is expected.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.1
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• pp.233-241
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• 1993

This study was conducted to characterise the sidestream from municipal wastewater treatment plants and its effects on the main treatment process. The flow rates and waste strengthes from each unit processes were measured and analysed, and finally determined its characteristics through the mass balance techniques. A laboratory scale completely mixed activated sludge was operated at $20^{\circ}C$ and fed in pulse with the sidestream to simulate the actual operating conditions. The study results indicated that the flow rates of sidestream ranged from 1.2 to 1.8 percent of the influent flow. However, the organic and nutrient loading rates could be increased to about 20 to 30 percent at an average, but 40 to 70 percent at a peak condition. It appears that the impurities from the sidestreams were not easily settled and resulted in lower primary efficiency. Consequently, it increased the organic loading rates to the aeration tank and the efficiencies were decreased at least about 10 percent at an average in comparison to the ordinary condition without the sidestream. With the peak condition, the efficiencies could not reach more than 80 percent for the organic removal and 50 percent for the nitrification.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1141-1145
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• 2005

A contactor coupled sequencing batch reactor composed of pre-anoxic contact zone and intermittently aerated zone was proposed and operated for nitrogen removal. Emphasis was placed on the fact that the contactor can be operated in a rapid reaction mode that results In biological uptake but incomplete metabolism of organic matter. Consequently, 61.2% of the sewage SCOD was adsorbed to activated sludge by 30-minute contact reaction. The specific uptake of organic matter was 22.3 mg SCOD/g MLVSS that enhanced the denitrification efficiency in the following denitrification stage. The removal efficiencies of the organic matter(SCOD) and the total nitrogen(T-N) were 86% and about 60% at the TCOD/TKN ratio as low as 6.0, respectively.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.3
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• pp.199-205
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• 2015

Organic wastes such as food waste (FW), livestock wastewater (LW), and sewage sludge (SWS) can produce hydrogen ($H_2$) by anaerobic acid fermentation. Expecially, FW which has high carbohydrate content produces $H_2$ and short chain fatty acids by indigenous $H_2$ producing microorganisms without adding inoculum, however $H_2$ production rate (HPR) and yield have to be improved to use a commercially available technology. In this study, LW was mixed to FW in different ratios (on chemical oxygen demand (COD) basis) as an auxiliary substrate. The mixture of FW and LW was pretreated at pH 2 using 6 N HCl for 12 h and then fermented at $37^{\circ}C$ for 28 h. HPR of FW, 254 mL $H_2/L/h$, was increased with the addition of LW, however, mixing ratio of LW to FW was reversely related to HPR, exhibiting HPR of 737, 733, 599, and 389 mL $H_2/L/h$ at the ratio of FW:LW=10:1, 10:2, 10:3, and 10:4 on COD basis, respectively. Maximum HPR and $H_2$ production yield of 737 $H_2/L/h$ and 1.74 mol $H_2/mol$ hexoseadded were obtained respectively at the ratio of FW:LW=10:1. Butyrate was the main organic acid produced and propionate was not detected throughout the experiment.

• Journal of Korean Society on Water Environment
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• v.22 no.2
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• pp.250-257
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• 2006

The objective of this study is to propose an alternative process for the small sewage treatment plants in rural communities. A biofilter has been used for biological wastewater treatment, which is becoming the alternative to the conventional activated sludge system. The proposed process used in this study, which is packed with floating media (i.e. expanded polystylene), has advantages of biofilter system and alternative flow system and they are incorporated into one process. Pilot and bench scale studies were performed using domestic wastewater. In the results of pilot plant study, it was observed that the stable effluent water quality was achieved and it met the present effluent criteria of suspended solid (SS), organic matters, T-N and T-P. In the study for determination of the cycle of backwashing, it was observed that the cycle of backwashing depended on BOD loading rates of influents. In the BOD loading rates of $0.5kg\;BOD/m^3{\cdot}day$ and $1.0kg\;BOD/m^3{\cdot}day$, the backwashing cycle of 28 hour and 16 hour were needed, respectively. The optimum backwashing time was 120~80 seconds at the media expansion rate of 50%. In the removal of SS, organic matters, T-N and T-P, SS removal was rather achieved by physical filtration than biological mechanism and the removal of organic matters except for SS, T-N and T-P were mainly rather achieved by biological mechanism than physical filtration. In bench-scale study, the effects of recirculation rate was investigated on removal of SS, TCOD, T-N and T-P. It was observed that the recirculation made removal efficiencies of SS, TCOD, T-N and T-P increased. Especially, in T-N removal, the increase of T-N removal efficiency of 40% was observed in the reicirculation rate of 1Q compared with 0Q.