• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.125-125
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• 2003

Recirculating aquaculture systems consist of different treatment compartments that maintain water quality within the ranges of commonly recommended for fish culture. This paper presents the common considerations in designing different treatment compartments as well as the engineering criteria in designing closed recirculating aquaculture system including a circular tank for fish culture, a sedimentation basin and a foam fractionator for solids removal, two styrofoam bead filters for TAN removal, a sand filter for nitrate removal, and aerators. The main purpose is to outline a common procedure in designing of closed recirculating aquaculture system for marine fish culture.

• Ocean and Polar Research
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• 제26권1호
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• pp.102-111
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• 2004

Recirculating aquaculture system (RAS) consists of different treatment compartments that maintain water quality within the ranges commonly recommended for fish cultures. However, common RASs still exert considerable environmental impact since concentrations of organic matter and nutrients in their effluents are high. Compared with the traditional RAS, the model RAS developed here use a sedimentation basin for digestion purposes and then use the released volatile organic matter to stimulate a denitrification process. Different treatment compartments for solids, total ammonia nitrogen, and nitrate removal have been reviewed. This paper provides the basic information on designing different treatment compartments as well as the engineering criteria in closed seawater RAS, consisting of circular tanks for fish cultures; dual drain systems, sedimentation basins and foam fractionators for removal of solids; nitrification biofilters for TAN removal; denitrification biofilters for nitrate removal; and aerators for aeration. The main purpose is to outline a common procedure in designing of closed RAS for marine fish culture with an emphasis on easy management and low expense, as well as reduction of the environmental impact.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2003년도 춘계 수산관련학회 공동학술대회발표요지집
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• pp.221-222
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• 2003

Typically, closed production system units are subject to an accumulation of fine suspended solids and dissolved organics (Weeks et at., 1992). Foam fractionation process is believed to be most effective in marine application for solids removal. In present experiment, the performance of foam fractionator for removal of solids, protein, and other dissolved materials was evaluated at different foam overflow heights and air flow rates in a pilot-scale recirculating aquaculture system for culture of Korean rockfish. (omitted)

• 환경생물
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• 제37권2호
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• pp.129-135
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• 2019

이 연구는 초기 넙치종묘(2.69±0.35 g)를 바이오플락으로 6개월간 1차 양성한 넙치를 이용하여, 침전조 매질(대조구, 바이어볼, 파판)별 7개월간 사육양성을 수행하였다. 7개월간 모니터링 결과 수질은 초기 이후, 주요 독성물질인 암모니아 및 아질산 1 mg L^-1 이하로 안정적으로 유지되었다. 사료계수(FCR)는 사육 5~6개월에 대조구에서 유의적으로 낮게 나타났지만, 사육 7개월에는 높은 성장을 나타내며 다른 구간과 비슷한 사료계수를 나타내었다. 본 실험에서 모든 시스템에서 안정적인 성장과 수질환경이 유지되었으며, 본 실험 모니터링 결과는 최근 환경오염으로 문제가 되고 있는 유수식 넙치양식에서 친환경 미래양식인 바이오플락으로의 전환을 위한 기초자료로 활용될 수 있을 것이다.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.126-126
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• 2003

Performance of a laboratory scale closed seawater recirculating aquaculture system was evaluated. Twenty-kg Korean rockfish (130 fish) with an average body weight of 153.8 g was stocked. Over 107-day culture period, fish reached final density of 51.7 kg/m$^3$ (initial density, 33.3 kg/m$^3$) on the culture tank volume basis. On a daily basis, water addition was 3.4% of the total water volume in the system. Total ammonia nitrogen (TAN)concentrations were below 1 mg/L and nitrite nitrogen (NO$_2$-N) concentrations were within the range of 1-3 mg/L on most sampling days. TAN was removedin bead and sand filters and it was removed or produced in the sedimentation basin. Basically, NO$_2$-N was removed in the bead and sand filters while it was either removed or produced in the sedimentation basin. Nitrate nitrogen (NO$_3$-N) was produced in the bead filters and removed in the sand filter and sedimentation basin. Foam fractionator performed well in the recirculating system. The maximal daily removal values for total suspended solids (TSS) and protein were 10,9 g and 1.4 g, respectively. Whole water quality parameters were within the levels commonly recommendedfor fish culture on most of the sampling days. However, further studies are needed to evaluate the commercial feasibility of this system because of the small-scale system used in present experiment. At least, present study still provides some basic information for further studies of this kind of system.

• Ocean and Polar Research
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• 제25권4호
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• pp.493-501
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• 2003

Performance of a laboratory scale closed seawater recirculating aquaculture system was evaluated. Twenty-kg of korean rockfish (130 fish) with an average body weight of 153.8g was stocked. Over a 107-day culture period, fish reached final density of $51.7kg/m^3$ (initial density, $33.3kg/m^3$) on the basis of the culture tank volume. On a daily basis, added water amounted to 3.4% of the total water volume in the system. Total ammonia nitrogen (TAN) concentrations were below 1mg/l and nitrite nitrogen $(NO_2-N)$ concentrations were within the range of 1-3mg/l on most sampling days. TAN was removed from bead and sand filters and it was removed or produced in the sedimentation basin. Basically, $NO_2-N$ was removed in the bead and sand filters, while it was either removed or produced in the sedimentation basin. Nitrate nitrogen $(NO_3-N)$ was produced in the bead filters and removed from the sand filter and sedimentation basin. The foam fractionator performed well in the recirculating system. The maximal daily removal values for total suspended solids (755) and protein were 10.9g and 1.4g, respectively. Whole water quality parameters were within the levels commonly recommended for fish culture on most of the sampling days. However, further studies are needed to evaluate the commercial feasibility of this system because of the smallscale system used in present experiment. At least, the present study still provides some basic information for further studies of this kind of system.

• 한국수소및신에너지학회논문집
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• 제21권3호
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• pp.220-226
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• 2010

The heat transfer performance improvement in closed cooling water system of an electric power generation can be achieved by a corrosion control using corrosion inhibitors. The effect of trisodium phosphate and sodium nitrite upon carbon steel at various $Cl^{-1}$ ion containing water concentrations was examined by an integrated corrosion monitoring system. Nitrite was found to be the most effective inhibitor among tested inhibitors for carbon steel. The inhibiting process is considered as adsorption of nitrite ions in oxide layer which form a passive film on the carbon steel surface.

• 한국수산과학회지
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• 제28권4호
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• pp.457-468
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• 1995

현재 유수식 방법으로 양식되고 있는 넙치(Paralichthys olivaceus)의 육상수조 양식에서 환수율, 월동시가온 및 양식배수 등의 문제를 해결하기 위하여, 실제 양식장에 설치한 반폐쇄식 순환여과 사육시스템을 이용하여 1992년 2월부터 1994년 1월까지 2년 동안(실험 I , 실험II) 넘치를 사육하면서 그 실용성을 연구하였다. 실험 I에서는 평균전장 7.5cm, 평균체중 3.4g, 실험II에서는 각각 5.0cm, 1.8g의 종묘를 사용하였다. 실험 I의 사육수 용존 무기태질소량은 $NH_4-N\;0.247-0.512ppm,\;NO_2-N\;0.010-0.043ppm,\;NO_3-N\;0.108-0.342ppm$ 실험II에서는 각각 0.091-0.715ppm, 0.002-0.045 ppm, 0,007-0.277 ppm 범위에서 변화하였다. 일간섭식률은 실험 I $0.67-2.41\%$, 실험II $0.69-2.22\%$, 사료효율은 각각 $34.8-59.8\%,\;40.5-88.4\%$였다. 실험 I에서의 어체는 사육 340일만에 전장 40.0-42.8cm, 체중 695.0-852.6g으로 성장하였고, 실험II에서는 사육 365일후에 전장 36.7-39.7cm, 체중 552.4-706.4g으로 자라났다. 사육종료시 어체의 평균 생존율은 실험 $192.0\%$, 실험II $96.0\%$였다. 어체의 체표면적이 수조바닥을 덮는율(covering rate)은 넙치의 수용밀도의 지표로 활용 가능하였다. 사육시 어체의 최대 수용량은 실험 I에서 덮는율 2.2, 중량 $34.1kg/m^2$였고, 실험II에서는 각각 $2.6,\;36.3kg/m^2$였다. 순환여과식 양식시스템은 현행의 유수식 양식시스템에 비해 양식 생산성 및 연안 환경오염 방지에 기여도가 높은 양식방법으로 평가되었다.

• 한국해양공학회지
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• 제13권3B호
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• pp.29-37
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• 1999

Ventilation of the marine engine room is very important for the health of the workers as well as the normal operation of machines. To find proper ventilation conditions of this engine room, numerical simulation with standard k-${\epsilon}$ model was carried out. In the present study, the marine engine room is separated to two floors with porus horizontal partition and considered as a closed space with a heat source and forced ventilation ducts. The porosity of horizontal partition is found to be important. For the engine room with 2 supply ports & 2 exhaust ports, the increasing of the porosity of horizontal partition is effective to reduce the recirculation flow zone in the second floor. When the engine room is ventilated with three supply air ports & one exhaust port, the increasing of the porosity of horizontal partition is effective to reduce the recirculating flow zone in the exhaust air area, but there is a possibility of local extreme heating at the lower side of engine near bottom.

• Environmental Analysis Health and Toxicology
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• 제12권3_4호
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• pp.43-54
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• 1997

Species, doses and routes extrapolation can be sucessfully carried out by using a physiologically-based pharmacokinetic (PBPK) approach. And PBPK approach to assess risk of hazardous chemicals is reasonable whatever the exposure scenarios are happened. Both partitioning coefficients of chemical between tissue and blood and enzymatic metabolic rate constants are key parameters to build up the PBPK model. In this study, we tried to estimate in vitro metabolic rate constants using a special apparatus instead to measure the in vivo constants which are used to PBPK simulation since the in vitro tests are less expensive and more convenient than in vivo tests. For the purpose, we designed and tested the new system to measure continuously the headspace concentration of VOC. The newly designed system is composed with a diffusion chamber which generates gaseous substrate, a reaction vessel with a recirculating pump to establish a closed system, an autbmatic sampler from a gas phase, a gas chromatography to analyze the headspace. In addition, a cold water condenser is attached between the reaction vessel and pump to reduce the content of gaseous moisture which interferes with chemical analysis. To validate the newly developed methodology, in vitro metabolic rate constants of trichloroethylene (TCE) as a prototype VOC were estimated by simulating observed results with an ACSL program. The simulated results are consistent to those estimated by the other research groups. This finding suggests that our newly designed closed system may be a useful apparatus to estimate in vitro metabolic rate constants for VOC.