• Environmental Engineering Research
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• 제10권1호
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• pp.7-14
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• 2005

The feasibility of hydrogen production with a raw seed sludge through direct acclimation of feedstock was investigated at acidogenic stage, and methane was harvested at followed methanogenic stage in an anaerobic two-stage process. Hydrogen content was higher than 57% at all tested organic loading rates (OLRs) and the yield of hydrogen ranged from 1.5 to 2.4 mol H2/mol hexose consumed and peaked at 6 gVSl-1day-1. Normal butyrate and acetate were main volatile fatty acids (VFAs), whereas the concentration of propionate was insignificant. The hydrogen-producing bacteria, Clostridium thermosaccharolyticum, was detected with strong intensity at all tested organic loading rates (OLRs) by denaturing gradient gel electrophoresis (DGGE) of the polymerase chain reaction (PCR) analysis. From COD balance in the process, the fraction of the feed-COD converted to the hydrogen-COD at acidogenic stage ranged from 7.9% to 9.3% and peaked at 6 gVSl-1day-1, whereas the fraction of feed-COD converted to the methane-COD at methanogenic stage ranged from 66.2% to 72.3% and peaked at 3 gVSl-1day-1.

• 한국물환경학회지
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• 제20권6호
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• pp.583-588
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• 2004

This research examined the treatment efficiency and methane production rate in treating slurry-type swine waste using UASB (upflow anaerobic sludge blanket) reactor. The UASB reactor was operated at an organics volumetric loading rate (VLR) of $2.6-15.7kgCOD/m^3/day$. A stepwise increase of the VLR resulted in a temporary deterioration in the COD removal rate in UASB reactor but recovered quickly. The COD removal rate were 65-70% for VLR up to $5 kgCOD/m^3/day$. When organics VLR was $10kgCOD/m^3/day$, the COD removal rate decreased sharply and there was loss of 17.537g of the seeding biomass due to sludge washout. This result indicated that the UASB system cannot be adapted to more than $10kgCOD/m^3/day$ of VLR. As the organic load increased from 2.6 to $15.7kgCOD/m^3/d$, the biogas production rate varied from 3.2 to 10.8 L/d and the methane conversion rate of the organic matter varied from 0.30 to $0.23m^3CH_4/kg\;COD_{removed}$. The methane content showed the range of 70.1-81.5% during the experimental period. The volatile solids (VS) removal efficiency was similar at the low VLR (< $5 kgCOD/m^3/day$), but it decreased sharply at the high VLR (> $5 kgCOD/m^3/day$). The VS reduction rate was, moreover, large those of COD. The result shows that hydraulic retention time above 2 days is essential in case of treating wastewater containing 1% of solids.

• Environmental Engineering Research
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• 제25권1호
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• pp.80-87
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• 2020

Landfill waste decomposition generates a dark effluent named, leachate which is characterized by high organic matter content. To minimize these polluting effects, it becomes necessary to develop an effective landfill leachate treatment process. The objective of this study was to evaluate the performance of an innovative approach based on air stripping, anaerobic digestion (AD) and aerobic activated sludge treatment. A reduction of 80% of ammonia and an increase of carbon to nitrogen ratio to 25 were obtained, which is a suitable ratio for AD. This latter AD was performed in fixed bed reactor with progressive loading rate that reached 2 and 3.2 g COD/L/d for the raw and diluted leachate (1:2), respectively. The anaerobic treatment led to significant removal of chemical oxygen demand (COD) and biogas production, especially for the diluted leachate. The COD removal was of 78% for the raw leachate and a biogas production of 4 L/d with 70% methane content. The use of the diluted leachate led to 81% of COD removal and 7 L/d biogas with 75% methane content. It allowed a removal of 77% COD and more than 97% of the organic compounds present in the initial leachate sample.

• 한국환경보건학회지
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• 제19권4호
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• pp.38-43
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• 1993

The characteristics of food wastewater treatment in an anaerobic packed bed reactor (APBR) with polyurethane as a packing material and sludge bed reactor (ASBR) was studied. The reactor of 9cm-ID, 150cm-height was fed in a continuous mode from bottom of reactor. For the purpose of constant temperature of reactor, water jacket was installed. The used packing materials was polyurethane sponge foam. Methane which was produced by decomposed organics collected at the top of the reactor for using as a fuel. The substrates used were synthetic, mixed and food wastewater. For the acclimatization of microorganisms, mixed wastewater was used. The major analyses were gas production, COD, pH and volatile acids. Based upon the completed works, the results are as follows: When food wastewater was fed the quantity of produced gas was less than that of synthetic wastewater, but food process saw higher methane content than synthetic process. As well as COD removal efficiency of food process reached at about 85%. In aspect of effluent volatile acid, food process showed low concentration of below 500 mg/l, therefore anaerobic reaction stabled. Conclusively food wastewater used can be digested by anaerobic treatment, especially anaerobic packed bed reactor showed 82% of COD removal, 75% of methane content, 10 l of gas production, and anaerobic sludge bed reactor did 79% of COD removal, 75% of methane content, 81 of gas production at 4 kgCOD/m$^3$day, 36$\circ$C.

• 환경위생공학
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• 제9권1호
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• pp.29-37
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• 1994

Anaerobic treatment of wastewater of the red- bean processing industry was carried out and discussed an anaerobic sludge bed reactor( ASBR) as a preliminary study to evaluate applicability of given processes. The dimension of reactor were same as 0.09m- ID$\times $1.5m- height. The type of substrate and the hydraulic retention time( HRT) were considered as experimental variables. The synthetic wastewater with glucose in the laboratory, the wastewater from the red bean processing industry mixed with synthetic wastewater with variation of mixing percent were fed as substrate. The hydraulic retention time was changed from one day to five days. The gas production, the methane content in produced gas, efficiencies of COD removal and 55 removal were evaluated as principal characteristics. With synthetic wastewater as a substrate and at a hydraulic retention time of one day, characteristics of ASBR was the gas production(12$\ell$/day ), the methane content of produced gas(60%), the efficiency of COD removal(92%) and 55 removal(30%). With the real wastewater and at a hydraulic retention time of one day, the gas production and the efficiency of COD removal of the ASBR decreased with the proportion of real wastewater. The gas production and the efficiency of COD removal with real wastewater only was decreased to 70% and 87% of those with synthetic wastewater only, respectively. However, the methane content in produced gas and the efficiency of 55 removal with real wastewater only was increased significantly by 1.25 times and two times of those with synthetic wastewater only, respectively. However, the methane content in produced gas and the efficiency of 55 removal with real wastewater only was increased significantly by 1.25 times and two times of those with synthetic wastewater only, respectively. With real wastewater only as a substrate in the ASBR, the gas production was decreased with an increase of HRT, but the efficiency of COD removal increased with HRTI like the usual trend reported. As a conclusion, the wastewater of the red- bean Processing industry could be treated by anaerobic digestion successfully in the ASBR.Anaerobic treatment of wastewater of the red- bean processing industry was carried out and discussed an anaerobic sludge bed reactor( ASBR) as a preliminary study to evaluate applicability of given processes. The dimension of reactor were same as 0.09m- ID$\times $1.5m- height. The type of substrate and the hydraulic retention time( HRT) were considered as experimental variables. The synthetic wastewater with glucose in the laboratory, the wastewater from the red bean processing industry mixed with synthetic wastewater with variation of mixing percent were fed as substrate. The hydraulic retention time was changed from one day to five days. The gas production, the methane content in produced gas, efficiencies of COD removal and 55 removal were evaluated as principal characteristics. With synthetic wastewater as a substrate and at a hydraulic retention time of one day, characteristics of ASBR was the gas production(12$\ell$/day ), the methane content of produced gas(60%), the efficiency of COD removal(92%) and 55 removal(30%). With the real wastewater and at a hydraulic retention time of one day, the gas production and the efficiency of COD removal of the ASBR decreased with the proportion of real wastewater. The gas production and the efficiency of COD removal with real wastewater only was decreased to 70% and 87% of those with synthetic wastewater only, respectively. However, the methane content in produced gas and the efficiency of 55 removal with real wastewater only was increased significantly by 1.25 times and two times of those with synthetic wastewater only, respectively. However, the methane content in produced gas and the efficiency of 55 removal with real wastewater only was increased significantly by 1.25 times and two times of those with synthetic wastewater only, respectively. With real wastewater only as a substrate in the ASBR, the gas production was decreased with an increase of HRT, but the efficiency of COD removal increased with HRTI like the usual trend reported. As a conclusion, the wastewater of the red- bean Processing industry could be treated by anaerobic digestion successfully in the ASBR.

• 한국물환경학회지
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• 제25권1호
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• pp.159-166
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• 2009

This study has been attempted to generate electricity, while simultaneously treating artificial organic wastewater using both batch and continuous microbial fuel cells (MFCs). In the batch MFC, current-voltage curve showed an onset potential of -0.69 V vs. Ag/AgCl. The potential range between this potential and 0 potential displayed an available voltage for an automatic production of electric energy and glucose, which was oxidized and treated at the same time. The 486 mg/L glucose solution showed the maximum power of $30mW/m^2$ and the maximum current density of $75mA/m^2$ shown in the power curve. As a result, discharging of the cell containing COD 423 mg/L at the constant current density of $60mA/m^2$ showed a continuous electricity generation for about 22 hours that dropped rapidly due to dissipating of organic material. Total electric energy production was 18.0 Wh. While discharging, the pH change was low and dropped from pH 6.53 to 6.20 then increased to 6.47, then stabilized at this charge. The COD treatment efficiency was found to be 72%. In the continuous MFC, COD removal tends to increase as the hydraulic retention time is increased. At one day of hydraulic retention time as the maximum value reaches the COD removal efficiency, power production rate and power production rate per COD removal that were obtained were 68.8%, $14mW/m^2$, and $20.8mW/m^2/g$ CODrm, respectively. In the continuous MFC, the power production rate per COD removal increases as the hydraulic retention time is increased and decreases as the organic loading rate is increased. At the values lower than an organic loading rate of $1kgCOD/m^3/d$, the values higher than about $18.1mW/m^2/g$ CODrm could be obtained.

• Applied Biological Chemistry
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• 제40권6호
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• pp.556-560
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• 1997

광합성세균을 이용한 고농도 유기폐수인 두부공업폐수의 정화처리와 동시에 두부공업폐수를 생물제초제인 ${\delta}-aminolevulinic$ acid (ALA) 생산용 대체기질로 이용할 목적으로 Rhodobacter capsulatus KK-10을 사용하여 COD 제거율과 ALA 생산능을 검토하였다. 사용된 두부공업폐수의 성상은 pH 4.2, COD/BOD와 BOD/N의 비율은 0.98 및 17.2, BOD : N : P의 함유비율은 10 : 6 : 4, 젖산 함유량 1,080 ppm 등으로 광합성세균의 생육에 적당한 조건이었다. 두부공업폐수에서 본 균주를 4일 동안 배양한 결과 약 94% COD 값의 감소와 1.2 g/l 균체생육을 보였으며 대수기 중기에서 ALA 탈수효소 저해제인 levulinic acid(LA)를 15 mM 첨가한 결과 55 mg/l의 ALA 생산량을 나타내었다. ALA의 전구물질인 succinate 및 glycine과 LA를 각각 15 mM의 농도로 동시 첨가시 최대 114 mg/l의 생산량을 보였다. 상기의 물질들을 각각 15 mM 농도로 연속 첨가한 후 ALA 생성량을 검토한 결과 LA 1회와 glycine과 succinate를 3회에 걸쳐 첨가하였을 때 120 mg/l로 가장 효과적이었으며 COD 제거율은 92%를 나타내었다.

• 해양환경안전학회지
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• 제12권3호
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• pp.165-170
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• 2006

육상 오염원의 영향을 적게 받는 완도 해역에서 약 10년간의 월별 수질자료를 이용하여 식물성플랑크톤의 증가에 의한 유기물의 증가에 대하여 분석하였다. 그 결과 DIN의 경우 겨울철인 2월에는 상대적으로 높은 농도인 0.138mg/L를 나타내고 있으며 여름철인 8월에는 0.052mg/L로 매우 낮은 값을 나타내고 있다. DIP의 경우도 DIN과 비슷한 경향을 나타내고 있으며 겨울철인 2월의 농도가 가장 높은 0.015 mg/1이고 여름철인 8월이 가장 낮은 값인 0.011 mg/1를 나타내고 있다. 식물성플랑크톤의 제한영양염을 알아보기 위하여 Redfield ratio(N:P=16:1)를 이용하여 제한영양염을 평가하여 보면 완도해역은 질소가 제한 영양염으로 나타나고 있다. 가장 제한이 되고 있는 계절은 여름으로 N/P의 비가 10.5로 나타났다 Chl.-a는 겨울철인 2월에 비해 봄과 여름인 5월과 8월에 79%, 97%가 증가하는 것으로 나타났다. 유기물의 농도는 COD로 나타내었으며 2월에는 0.84 mg/1로서 가장 낮은 값을 나타내었으며 8월인 여름철에 가장 높은 1.10 mg/1를 나타내었다. 영양염과 Chl.-a의 상관관계는 DIN과의 상관에서 $r^2$M가 0.93, DIP과의 상관에서 $r^2$M가 0.89로 매우 높게 나타났다. 이와 같은 결과는 식물성플랑크톤의 증식이 영양염의 감소에 주요 원인이라고 할 수 있다. 또한 Chl.-a와 COD의 회귀분석에서 상관계수 $r^2$M가 0.78로서 상관관계가 있는 것으로 나타났으며 회귀식을 이용하여 분석한 결과 유기물의 생산량은 겨울철에는 17%, 여름철에는 37%가 증가하는 것으로 나타났다. 위의 결과를 종합하면 완도의 해역에서 수온이 증가하는 여름철에 용존성 영양염의 농도는 감소하고 있으나 식물성플랑크톤의 지표가 되는 Chl.-a와 유기물의 지표가 되는 COD는 증가하는 것으로 나타났다. 또한 이들을 회귀분석을 통하여 분석한 결과 상관성이 매우 높은 것으로 나타났다.

• 한국환경보건학회지
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• 제21권2호
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• pp.20-26
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• 1995

The objective of this study is to estimate the effect of the bed expansion and the characteristics of attached biomass in the start-up in the anaerobic fluidized bed reactor(AFBR). The fluidized bed reactor was operated with bacteria supported on the bed of granular activated carbon(GAC). The reactor was operated at 35$\circ$C, 5 kg $COD/m^3\cdot day$ at bed expansion varying from 0 to 100% with soluble glucose wastewater(5,000 mg/l). When the effluent reached a steady state at 100% of bed expansion, maximum COD removal efficiency of 87.3% and 0.031 $m^3CH_4/kg COD_{removed}$ were obtained. At higher bed expansion, COD removal efficiency, methane production rate and biogas production rate increased. Especially, at 50% of bed expansion, the efficiency of the treatment increasedg rapidly in the AFBR. The biomass colonized in the pits and crevices of the GAC particle and no complete biofilm was established in the bioreactor during the experiment.

• Fisheries and Aquatic Sciences
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• 제8권3호
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• pp.177-181
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• 2005

Fishing selectivity is determined by the level of voluntary escaping behavior in accordance with decision-making based on the relationship between fish size and mesh size. This study examined movement during the swimming behavior of black porgy in a trawl's towing cod-end and analyzed the movement components such as swimming speed, angular velocity of turning, and distance to the net over time. Most of the observed fish exhibited an optomotor response, maintaining position and swimming speed without changing direction. Others exhibited erratic or 'panic' behavior with sudden changes in swimming speed and direction. The latter behavior involved very irregular and aperiodic variations in swimming speed and angular velocity, termed 'chaotic behavior.' Thus, the results of this study can be applied to a chaotic behavior model as a time series of swimming movements in the towing cod-end for the fishing selectivity.