• 한국수산과학회지
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• 제25권3호
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• pp.197-204
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• 1992

넙치양식장의 수질관리 및 제어 방안을 검토하기 위하여 같은 조건에서 양식되고 있는 유수식 및 순환여과식 양식장을 선택하여 상호수질의 비교 평가를 행하였다. 두양식장 공히 COD, $PO_4-P$ 및 SS의 최대농도는 급이와 동시에 나타났고 2시간 이내에 평상농도로 회복되어 일정한 농도로 거의 유지되었다. $NH_4-N$의 경우 유수식에는 급이후 시간 경과에 따라 농도차이가 별로 없으나 순환식의 경우는 급이후 2시간 이후에 다소 증가하는 경향을 보였다. $NH_4-N$을 제외한 COD, $PO_4-P,\;SS$ 및 TIN의 농도는 순환여과식에서 다소 높은 경향을 보였다. 이는 처리 시스템내에 축적된 유기부유물이 무기화에 기인된 것을 평가되었으며, 이것이 질산화율을 떨어뜨리는 결과를 초래한 것으로 사려되었다. 유수식 및 순환여과식의 수질에 직접적인 영향을 주는 해수 교환율이 양식장마다 크게 다르게 나타나 이에 대한 최적화가 시급한 것으로 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1681-1683
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• 2005

The molten carbonate fuel tell(MCFC) is endowed with the high potential especially in future electric power generation industry by its own outstanding characteristics. KEPCO(KEPRI) started a 100 kW MCFC system development program in 1993 and has been executed 100kW system develpilot plant successfully completed first phaseopment by 2005 on the basis of successful results of 25kW system development. In this program, the components and mechanical structure for 100 kW stack and system construction were completed on last year and now system pre-commissioning was being executed. A 100 kW MCFC power plant was constructed at the site of Boryeong Thermal Power Plant. A 100 kW MCFC system has characterized as a high pressure operation mode, $CO_2$ recycle, and externally reforming power generation system. The 100 kW MCFC system consisted with stacks which was made by two 50 kW sub-stacks, 90 cells with 6,000 cm2 active area and BOP including a reformer, a recycle blower, a catalytic burner, an inverter, and etc. The system will be operated under 3 atm pressure condition and expected to last over 5,000 hours by the end of this year.

• 대한환경공학회지
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• 제30권12호
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• pp.1231-1238
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• 2008

본 연구에서는 실험실 규모 2상 혐기성 소화를 이용하여 음식물 쓰레기 탈리액의 처리성을 평가하였다. 이를 위해 산발효조의 적정 유입 pH 및 HRT를 도출하고, 산발효조로의 메탄조 유출수 반송 효과, 메탄발효조에서 고형물 내부반송 및 온도의 영향을 파악하였다. 산발효조에서는 유입 pH 6.0, HRT 2일인 조건에서 메탄조 유출수 반송 후 산생성 및 VS 제거효율은 30% 및 40%에서 안정적으로 유지되었다. 유기물 부하 7 g COD/L/d 이하의 조건에서 고형물 내부반송에 의해 중온 및 고온메탄발효조의 유출수 SCOD는 반송 이전보다 낮거나 같은 수준으로 유지되었고 유기물 부하 증가에 따른 비메탄생성량(specific methane production, SMP)의 감소폭이 줄어들었다. 고형물 내부반송 이후 동일한 유기물 부하에서 COD 제거효율과 SMP는 중온메탄발효조가 고온보다 우수하였으며 이는 중온메탄발효조의 MLVSS 농도가 고온보다 높기 때문인 것으로 판단되었다. 따라서 고온산발효-중온메탄발효로 구성된 시스템이 고온산발효-고온메탄발효보다 COD 제거와 메탄발생면에서 우수한 것으로 나타났다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
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• pp.140-148
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• 2005

The molten carbonate fuel cell (MCFC) is endowed with the high potential especially in future electric power generation industry by its own outstanding characteristics. KEPCO (KEPRI) started a 100 kW MCFC system development program in 1993 and has been executed 100kW system develpilot plant successfully completed first phaseopment by 2005 on the basis of successful results of 25kW system development. In this program, the components and mechanical structure for 100 kW stack and system construction were completed on last year and now system pre - commissioning was being executed. A 100 kW MCFC power plant was constructed at the site of Boryeong Thermal Power Plant. A 100 kW MCFC system has characterized as a high pressure operation mode, CO2 recycle, and externally reforming power generation system. The 100 kW MCFC system consisted with stacks which was made by two 50 kW sub-stacks, 90 cells with 6,000 cm2 active area and BOP including a reformer, a recycle blower, a catalytic burner, an inverter, and etc. The system has been operated from 13th of September on this year and produced 50 kW AC under atmospheric pressure condition and expected to operate by the end of this year.

• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1369-1373
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• 2009

Succinic acid was produced by continuous fermentation of Actinobacillus succinogenes sp. 130Z in an external membrane cell recycle reactor to improve viable cell concentration and productivity. Using this system, cell concentration increased to 16.4 g/l at the dilution rate $0.2\;h^{-1}$, up to 3 times higher than that of batch culture, and the volumetric productivity of succinic acid increased up to 6.63 g/l/h at the dilution rate $0.5\;h^{-1}$, 5 times higher than that of batch fermentation. However, in the continuous culture using a high dilution rate, operational problems including severe membrane fouling and contamination by lactic acid producer were observed. Another succinic acid producer, Mannheimia succiniciproducens MBEL55E, was also utilized in this system, and the cell concentration and productivity of succinic acid at the dilution rate of $0.3\;h^{-1}$ were found to be above 3 and 2.3 times higher, respectively, compared with those obtained at the dilution rate of $0.1\;h^{-1}$. These observations give a deep insight into the process design for a continuous succinic acid production by microorganisms.

• 한국미생물·생명공학회지
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• 제13권1호
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• pp.33-39
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• 1985

The effects of initial concentration, flow rate, and recycle ratio on the removal efficiency of phenol were studied in a tapered fluidized bed reactor packed with activated carbon which was attached with Candida tropicalis. The optimum conditions of Candida tropicalis were showed that pH was 7.0 and temperature was $30^{\circ}C$, and the specific growth rate of Candida tropicalis was satisfied with the Monod equation up to 500 mg/L of phenol, and beyond it the inhibition of substrate was found. According to the increases of initial concentration and flow rate, the removal efficiency was decreased, as the recycle ratio was increased, the removal efficiency was increased. In the case of flow rate of 10mL/sec and the recycle ratio of 2, the removal efficiency was 90% above for the all of initial concentration. The removal rate of phenol was the first order reaction in this system, and the rate equation of reaction was as follows.

• 상하수도학회지
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• 제21권5호
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• pp.589-599
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• 2007

This study was conducted to investigated the removal efficiency of BOD and nutrient for the treatment of low strength municipal wastewater by a biological nutrient removal system. In this experiment, the effect of operating parameter including HRT of 7.0hr, BOD/TN ratios of 2.62~4.08, internal recycle of 50~300%, and return sludge of 50~100%, were studied during winter season. Efficiencies of organic matter and T-P removal and denitrification were not significantly affected by the change of temperature in winter season. However, the specific nitrification rate and nitrification efficiency decreased at low temperature. Besides, denitrification efficiencies increased with increasing BOD/TN ratios. It was also found that the internal recycle and return sludge ratio below 50% is required for the effective denitrification of low strength municipal wastewater. With operating mode 4 of the optimum, the effluent BOD, T-N and T-P concentration were obtained to average 5.8, 14.6, and 0.84 mg/L, respectively. The temperature-activity coefficient (${\theta}$) of specific nitrification rate, specific denitrification rate and specific phosphorus uptake rate were obtained 1.044, 1.017, 1.028, respectively.

• 한국환경과학회지
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• 제6권4호
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• pp.409-415
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• 1997

In order to Investigate the possibility as a simple technique of wastewater treatment for recirculating aquaculture system, the experiment by a biofilter unfit was carried out. The high and stable removal efficiency of nitrogen could be obtained by selecting the optimum recycle ratio and DO concentration. It was found that the proper combination of nitrifacation and denitrfication step in the reactor would be required for increasing the removal efficiency. The extent of nitrogen removal gradually decreased UO the rise of re- cycle ratio since the depression of denitrificatlon by the lack of hydrogen donor. The depression of nitrogen removal was overcome by increasing the CIN ratio In the wastewater. The extent of phosphorus removal was increased slightly with the increase of DO concentration and recycle ratio, but high removal efficiency was not observed. However, the extent of COD removal was not affected by recycle ratio and DO concentration and showed the stable removal of above 90%.

• 환경영향평가
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• 제21권1호
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• pp.63-69
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• 2012

Sediment has been increasingly acknowledged as a carrier in water system and an available contamination. For this reason, dredging of sediment in reservoir to remediate water quality and secure storage capacity is conducted annually. However, disposal of numerous dredged sediment is necessary as a secondary problem. Currently, in Korea, dredged sediment is classified as waste to be reclamated or recycled into sandy soil, however, they are still in trouble because of spacial and environmental problem. Therefore, rather than simple disposal or reuse into sandy soil, it is necessary to research on method to manage main cause of pollution and increase the value as a resource. In this study, we intend to develop a recycle technology for numerous dredged sediment produced by dredging in deteriorated reservoirs using solidificator (stabilizer). To achieve this, we will consider utilization of dredged sediment and evaluation of use possibility as natural recycle by analysis the characteristics of soil-solidificator mixture in terms of physicochemical properties and the mixing ratio between sediment and solidificator.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
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• pp.638-641
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• 2004

본 연구에서는 기존의 철거개념과는 달리 건설폐기물의 발생량을 최소화하고 자원의 재활용률을 높이기 위한 최적의 분별해체 관리시스템을 제시하고자 한다. 본 시스템은 해체량의 산정에서부터 각 구조부위별 해체방법, 발생된 자원의 활용계획 등을 사전에 계획하고 운영하게 함으로서 국가 전체 건설폐기물의 발생량을 저하시킴으로서 환경부하량을 최소화하는데 큰 기여를 하는 것을 목적으로 한다. 본 시스템의 구성은 크게 해체사전조사계획, 해체물량산정, 해체공사계획, 폐기물관리계획의 4개 모듈로 구성되어 있고, 이 모듈은 사용자의 사용 목적에 따라 모듈별로 사용하는 것이 가능하다.