• Journal of Korean Society of Environmental Engineers
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• v.33 no.7
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• pp.492-500
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• 2011

Antibiotic resistant microbes were isolated in catfish, trout, eel and loach aquaculture effluent. The distribution of antibiotic resistant microbes in aquaculture effluent and the disinfection efficiency of antibiotic resistant microbes by electron beam irradiation were investigated. It was shown that the multi-drug resistant bacteria were Aeromonas sp., Citrobacter sp., Bacillus sp., Marinobacter sp., Pantoea sp., Pseudomonas sp. and Enterobacter sp. in aquaculture effluent. 41.7% of total strains showed the resistance against one antibiotic agent, and 58.3% of total strains showed the resistance against more than two antibiotics. It was evidently shown that the toxicity and physicochemical properties of antibiotics can be estimated using Quantitative Structure Analysis Relationship (QSAR). Electron beam irradiation was very effective for the disinfection of antibiotic resistant bacteria from aquaculture effluent, in which the disinfection efficiency was approximately 99.9% with electron beam of 1 kGy.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.1
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• pp.10-16
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• 2022

Interest in effluent treatment is currently increasing and the use of polymetric coagulants is considered as a pretreatment of physical filtration prior to effluent discharge to increase solids recovery. A jar test evaluated effluent treatment efficiency of polymeric coagulants for semi-recirculating aquaculture systems. The particle coagulation efficiency and distribution were evaluated at different polymer dosages in freshwater and seawater effluents. The polymer was added at 0.005-0.08 mL/g of total suspended solids (TSS) in the effluents. TSS in the supernatant after coagulation decreased with increasing polymer dose in the freshwater, while showing no corresponding changes with dose in the seawater. However, in all treatments for both effluents, the removal efficiency was above 90%, regardless of the dose in the tested range. Both the De Brouckere Mean Diameter (DBMD) and volumetric median diameter (VMD) were all above 100 ㎛ in the freshwater effluent. In the seawater effluent, the particle size appeared to be larger than that in freshwater, ranging from 400-1,000 ㎛ for both DBMD and VMD. Considering that the typical pore size of physical filtration in aquaculture is between 60 and 200 ㎛, the use of polymers is expected to improve the practicality of physical filtration for efficient treatment.

• ALGAE
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• v.26 no.3
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• pp.253-263
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• 2011

Phenotypic plasticity was examined in the economically and ecologically important brown alga Ascophyllum nodosum in southwestern Nova Scotia, considering specifically how nutrient loading affected its vegetative and reproductive features. To determine this, we examined morphometric changes in A. nodosum from two sites receiving direct effluent impacts from a land-based finfish aquaculture facility and from two control sites, approximately 2 km away from the aquaculture facility in opposite directions. Fronds from test sites were significantly younger than from control sites (5 y vs. 8 y); however, fronds from farm sites were significantly larger (219 g vs. 90 g) because of their higher growth rates. Thalli from farm sites had greater reproductive potential, as shown by numbers of receptacle initials (797 initials vs. 281 initials). These results suggest limited nutrient inflows from land-based aquaculture may positively affect adjacent Ascophyllum populations by inducing higher growth rates. We conclude that the coordination of effluent management from land-based aquaculture with natural resource harvesting of A. nodosum may be beneficial. Further study is necessary to determine the limits of nutrient loading for this potentially beneficial outcome.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.4
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• pp.315-326
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• 2013

This study investigated the temporal-spatial distribution and variations in water quality parameters (temperature, salinity, pH, DO, COD, SPM, DIN, DIP, silicate, TN, TP, and chlorophyll-a) in the coastal area of Jeju, Korea, adjacent to aquaculture ponds (Aewol-ri, Haengwon-ri, Pyosun-ri, and Ilkwa-ri). Data were collected bimonthly from February 2010 to December 2011. A principal component analysis (PCA) identified three major factors controlling variations in water quality during the sampling period. Aquaculture effluent water led to large changes in nutrient levels. The highest nutrient values were observed during the investigation period. The relatively large increase in organic matter at the sampling stations coupled with sea area runoff events during the summer rainy period. Variation in chlorophyll-a concentration was mainly driven by meteorological factors such as air temperature and rainfall in the coastal areas of Aewol and Haengwon. In the coastal areas of Pyosun and Ilkwa, pollution was caused by anthropogenic factors such as discharge of aquaculture effluent water. High nutrient concentrations at the majority of the coastal stations indicate eutrophication of coastal waters, especially within a distance of 300 m and depth of 10m from drainage channels. Coastal eutrophication driven by aquaculture effluent may be harmful inshore. Events such as eutrophication may potentially influence water pollution in aquaculture ponds when seawater intake is detected because of aquaculture effluent water.

• Journal of Aquaculture
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• v.16 no.4
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• pp.252-256
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• 2003

Effluent from farm trefish contained high concentrations of nitrogen and phosphorus, such kinds of nutrients were released to the environment without proper treatment and thses increased the pollution of the environment. We evaluated the conventional treatment system with cost effective ecotechnologies for the removal of nutrients. Water lettuce chambers were investigated under the various experimental conditions to improve the efficiency of N&P removal and the treatment of from aquaculture effluent. In this research, six water lettuce chambers (80 liter each) received combination of aquaculture wastewater effluent at hydraulic retention times (HRTs) of 1, 2, 4 and 8days. The water lettuce chambers operated at a 8 day HRT investigated for aquaculture effluent (1'st) showed average removal efficiency, BOD, T-N, T-P of 92.8, 79.0 and 93.6% on average respectively.

• 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.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.107-113
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• 2012

Pollutants in aquaculture system effluent mostly originated from solid wastes including uneaten feed and excreta of cultured species. In this research, DAF(Dissolved Air Flotation) unit is suggested as an integrated solid control unit especially as a form of IIBG(Inline Injection Bubble Generation) process in aquaculture system. Solid removal performance of DAF unit was examined under various operation and salinity conditions with turbidity and suspended solid. Solid waste removal efficiencies were found to be affected by operation conditions including saturator pressure, recycle ratio, coagulant concentration. Solid removal efficiency was higher under higher saturator pressure and recycle ratio under which condition larger number of bubbles is generated. Coagulant is thought to have important role in creating bubble-particle aggregate by showing better removal efficiency with higher concentration. However higher saline water showed less effectiveness in removing solids by DAF(IIBG). Application of DAF(IIBG) process also showed additional effect in phosphate removal and DO(Dissolved Oxygen) supply. Phosphate existed in polluted water was removed up to 46% after treatment, which is thought to attribute to aluminium phosphate precipitation. And DO concentration was found to increase over 50% of initial saturation concentration after the injection of micro-bubbles. Through experiments on solid removal from aquaculture effluent, DAF(IIBG) process is estimated to be effective solid control method. This property can help aquaculture system being installed and operated simply and effectively.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.131-139
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• 2012

Field experiment was performed from June 2010 to July 2011 to evaluate pollutants removal efficiency in the constructed wetland system for the treated wastewater and the river water. The wetland systems were constructed near Gyungan river. Two different systems with meandering shape were compared for seasonal base and operational period base. Several kinds of aquaculture are planted through the corridor of wetland system. Average removal rate of BOD, T-N and T-P for A system were 15.8%, 14.8% and 26.5%, respectively. Average removal rate of BOD, T-N and T-P for C system were 23.5%, 27.8% and 10.6%, respectively. The effluent from two wetland systems often exceeded effluent water quality standards for wastewater influent, however effluent water quality standards for river water. However, the wetland system can be useful to treat polluted river water and effluent from wastewater plant. Removal rate of pollutants in seasonal variation was the highest in summer for BOD and T-N, however the removal rates of T-P were higher in spring and autumn than in summer.

• 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%, $5-8{\mu}m$).

• Journal of Aquaculture
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• v.15 no.4
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• pp.261-266
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• 2002

The effluent sediment from the land-based seawater fish farms of Jeju consists of proteins, fats, ash and moisture. An evaluation of the effluent sediment as substrate for growth of phototrophic or lactic acid bacteria revealed that the sediment supported the growth of phototrophic bacteria but could support lactic acid bacteria only on supplementation with sugar. The possibility of using phototrophic bacteria for recycling the land-based seawater fish farm effluent is shown.