• Title/Summary/Keyword: Recirculating

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Solids removal by foam fractionator in simulated seawater aquarium system

  • Lei Peng;Jo, Jae-yoon
    • Proceedings of the Korean Society of Fisheries Technology Conference
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    • 2003.05a
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    • pp.219-220
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    • 2003
  • The success of recirculating system depends largely on the treatment efficiency of waste generated in the system. fine solids were suspected to be responsible for fish kill in a recirculating system. Clogging of biofilter may be induced by high solids concentration in recirculating systems. Also, the solids could generate more ammonia nitrogen and oxygen demand if not removed out of recirculating system as soon as possible (Weeks et al., 1992). (omitted)

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Design and Performance of a Laboratory Scale Closed Seawater Recirculating System for Korean Rockfish Sebastes schlegeli Culture Part 1. Design of the Closed Seawater Recirculating System

  • Lei Peng;Oh, Sung-Yong;Jo, Jae-Yoon
    • Proceedings of the Korean Aquaculture Society Conference
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    • 2003.10a
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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.

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Removal of Suspended Solids Using a Flexible Fiber Filter in a Recirculating Aquaculture System (유연성 섬유사 여과기를 이용한 순환여과식 양식장의 부유고형물 제거)

  • Choi, Kwang-Soo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.40 no.2
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    • pp.73-78
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    • 2007
  • The suitability of a flexible fiber filter for removing suspended solid (SS) in a recirculating aquaculture system was evaluated. This study focused on variation in the performance with a change in filtering time, influent water quality, and filtering mode duration. The particle distribution diagram of the filter effluent showed that the number of particles bigger than $5-8{\mu}m$ decreased dramatically, and the removal efficiency exceeded 80%. Although the removal efficiencies of SS and chemical oxygen demand (COD) were dependent on the quality of the influent, the SS and COD concentrations of the effluent were not affected by the influent concentrations. This was despite the deterioration if water quality after feeding in the rearing tank. The performance of the filter was not affected by the filtering mode duration, feeding conditions, or filtering time. The SS concentration and turbidity of the recirculating-type rearing tank were 30% and 50% lower, respectively, than of the a non-recirculating-type rearing tank under the same operating conditions. The flexible fiber filter was applicable to a recirculating aquaculture system that uses plenty of seawater, based on its low filtering resistance $(2kg_f/cm^2)$, high flux $(330m^3/m^2/hr)$, and high fine particle removal efficiency (80%, $5-8{\mu}m$).

Numerical Analysis of A Vortex Cyclone in A Recirculating Aquaculture System (순환여과 양식장에서 와류형 분리기에 대한 수치적 검토)

  • Jeong, S.K.;Kim, E.
    • Journal of Power System Engineering
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    • v.9 no.1
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    • pp.36-41
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    • 2005
  • This study investigated the performance of a vortex hydrocyclone for solid removal in a recirculating aquaculture system. In a fish-breeding industry, effluent water is mainly disposed by gravity sedimentation. Thus, a large settling tank and a lot of water are needed to purify effluent water. However, this typical method does not show consistent efficiency. In case of low efficiency, discharged water contains a lot of feeding sediments. This causes environmental problems. Instead of this typical method a hydrocylone is tested to discharge water which contains a lot of feeding sediments. In this paper, a hydrocyclone with low velocity and pressure drop in a recirculating aquaculture system is investigated.

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Electrodeposition of GMR Ni/Cu Multilayers in a Recirculating Electrochemical Flow Reactor

  • Rheem, Young-Woo
    • Korean Journal of Materials Research
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    • v.20 no.2
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    • pp.90-96
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    • 2010
  • The recirculating electrochemical flow reactor developed at UCLA has been employed to fabricate nanostructured GMR multilayers. For comparison, Ni/Cu multilayers have been electrodeposited from a single bath, from dual baths and from the recirculating electrochemical flow reactor. For a magnetic field of 1.5 kOe, higher GMR (Max. -5%) Ni/Cu multilayers with low electrical resistivity (< $10\;{\mu}{\Omega}{\cdot}cm$) were achieved by the electrochemical flow reactor system than by the dual bath (Max. GMR = -4.2% and < $20\;{\mu}{\Omega}{\cdot}cm$) or the single bath (Max. GMR = -2.1% and < $90\;{\mu}{\Omega}{\cdot}cm$) techniques. Higher GMR effects have been obtained by producing smoother, contiguous layers at lower current densities and by the elimination of oxide film formation by conducting deposition under an inert gas environment. Our preliminary GMR measurements of Ni/Cu multilayers from the electrochemical flow reactor obtained at low magnetic field of 0.15 T, which may approach or exceed the highest reported results (-7% GMR) at magnetic fields > 5 kOe.

Performance Evaluation of Large Eddy Simulation for Recirculating and Swirling Flows (재순환 및 선회 유동에 대한 대와동모사(LES)의 성능검토)

  • Hwang Cheol-Hong;Lee Chang-Eon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.4 s.247
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    • pp.364-372
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    • 2006
  • The objective of this study is to evaluate the efficiency and the prediction accuracy of developed large eddy simulation (LES) program for complex turbulent flows, such as recirculating and swirling flows. To save the computational cost, a Beowulf cluster system consisting 16 processors was constructed. The flows in backward-facing step and dump combustor were examined as representative recirculating and swirling flows. Firstly, a direct numerical simulation (DNS) for laminar backward-facing step flows was previously conducted to validate the overall performance of program. Then LES was carried out for turbulent backward-facing step flows. The results of laminar flow showed a qualitative and quantitative agreement between simulations and experiments. The simulations of the turbulent flow also showed reasonable results. Secondly, LES results for non-swirling and swirling flows in a dump combustor were compared with the results of Reynolds-averaged Navier-Stokes (RANS) using standard $k-{\varepsilon}$ model. The results show that LES has a better performance in predicting the mean axial and azimuthal velocities, comer recirculation zone (CRZ) and center toroidal recirculation zone (CTRZ) than those of RANS. Finally, it was examined the capability of LES for the description of unsteady phenomena.

Analysis of Flows in the Combustor with Recirculating Flow Regime (재순환영역을 가지는 연소기내의 연소유동해석)

  • 신동신;허남건
    • Journal of the Korean Society of Propulsion Engineers
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    • v.1 no.2
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    • pp.22-31
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    • 1997
  • We developed a general purpose program for the analysis of flows in the combustor with recirculating flow regime and simulated the flows. The program uses non-staggered grids based on finite volume method and the primitive variables are cartesian velocities. The combustion model is irreversible one step reaction with infinite chemistry The Favre averaged governing equations are considered and the clipped gaussian distribution is considered as a probability density function of the conserved scalar. We calculated turbulent diffusion flame with recirculating flow regime. Simulation shows two recirculating regions like experimental results. Velocity, turbulent kinetic energy, temperature and concentration distribution in simulation agree well with experimental data.

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Complete genome sequence of Flavobacteriaceae strain KCTC 52651 isolated from seawater recirculating aquaculture system (해수 순환여과양식시스템에서 분리된 Flavobacteriaceae 균주 KCTC 52651의 유전체 분석)

  • Kim, Young-Sam;Jeon, Young Jae;Kim, Kyoung-Ho
    • Korean Journal of Microbiology
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    • v.55 no.2
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    • pp.174-176
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    • 2019
  • A novel bacterium, designated strain RR4-38 (= KCTC 52651 = DSM 108068), belonging to the family Flavobacteriaceae was isolated from a biofilter in the seawater recirculating aquaculture system in South Korea. A single complete genome contig which is 3,182,272 bp with 41.9% G+C content was generated using PacBio RS II platform. The genome includes 2,829 protein-coding genes, 6 rRNA genes, 38 tRNA genes, 4 non-coding RNA genes, and 9 pseudogenes. The results will provide insights for understanding microbial activity in the seawater recirculating aquaculture system.

Power consumption prediction model based on artificial neural networks for seawater source heat pump system in recirculating aquaculture system fish farm (순환여과식 양식장 해수 열원 히트펌프 시스템의 전력 소비량 예측을 위한 인공 신경망 모델)

  • Hyeon-Seok JEONG;Jong-Hyeok RYU;Seok-Kwon JEONG
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.60 no.1
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    • pp.87-99
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    • 2024
  • This study deals with the application of an artificial neural network (ANN) model to predict power consumption for utilizing seawater source heat pumps of recirculating aquaculture system. An integrated dynamic simulation model was constructed using the TRNSYS program to obtain input and output data for the ANN model to predict the power consumption of the recirculating aquaculture system with a heat pump system. Data obtained from the TRNSYS program were analyzed using linear regression, and converted into optimal data necessary for the ANN model through normalization. To optimize the ANN-based power consumption prediction model, the hyper parameters of ANN were determined using the Bayesian optimization. ANN simulation results showed that ANN models with optimized hyper parameters exhibited acceptably high predictive accuracy conforming to ASHRAE standards.

Design and Development of Integrated Recirculating Aquaculture System (순환 여과식 양식 시스템의 설계 및 개발)

  • SUH Kuen-Hack;KIM Byong-Jin;JEON Im Gi
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.34 no.1
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    • pp.70-76
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    • 2001
  • An integrated recirculating aquaculture system suitable to our country's situation was designes and developed, The integrated recirculating aquaculture system consisting of a double drain type rearing tank of the $2.5 m^3$, a sedimentation tank for removal of settleable solids, a floating bead filter for the removal of suspended solids, a foam separator for removal of fine particles and a rotating biological contactor for the nitrification was designed and manufactured. The integrated recirculating aquaculture system was stocked with nile tilapia (Oreochromis niloticus) at $2\%$ rearing density for 2 weeks. Feed coefficient was 1.4 and average daily growth rate was $0.64\%$ in the system for 2 weeks.

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