• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.428-437
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• 2023

A simultaneous analytical method was developed and validated for the analysis of prohibited fluoroquinolone (FQ) antibiotics including norfloxacin, ofloxacin, and pefloxacin, released by aquaculture in seawater and effluents. The samples were filtered, and extracts were obtained using a solid phase extraction cartridge with methanol (MeOH). The extracts were concentrated, and analyzed using ultra-performance liquid chromatography-tandem mass spectrometry. Two different columns and four different mobile phases were compared to achieve optimal separation and sensitivity for target compounds. Typical validation parameters including linearity, recovery of surrogate standard, instrument detection limit (IDL), limit of quantification (LOQ), and method detection limit (MDL) were evaluated. The linearity of calibration curves was over 0.999. Recoveries of surrogate ranged from 87.6% to 113%. The LOQ of target compounds was approximately 3-8 times lower than those reported in previous studies. The IDL and MDL were 0.06-0.57 and 0.06-0.37 ng/L, respectively. Seven effluent samples collected from an aquaculture located in Jeju were analyzed; however, not all target compounds were detected in the samples, suggesting that the banned antibiotics were not used. Overall, this established method was able to simultaneously analyze the three FQ antibiotics, and may be useful for monitoring prohibited antibiotics in the fishery industry.

• Journal of Korean Society of societal Security
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• v.4 no.2
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• pp.73-78
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• 2011

In order to resolve the problem of change in global climate which is worsening as days go by and to preemptively cope with strengthened restriction on carbon emission, the government enacted 'Framework Act on Low Carbon Green Growth' in 2010 and selected green technology and green industry as new national growth engines. For this reason, the necessity to use the un-utilized waste heat across the whole industrial system has become an issue, and studies on and applications of recycling in the agricultural and fishery fields such as cultivation of tropical crops and flatfishes by utilizing the waste heat and thermal effluent generated by large industrial complexes including power plants are being actively carried out. In this study, we looked into the domestic and overseas examples of having utilized waste heat abandoned in the form of power plant thermal effluent, and carried out economic efficiency evaluation of sturgeon aquaculture utilizing thermal effluent of Yeongwol LNG Combined Cycle Power Plant in Gangwon-do. In this analysis, we analyzed the economic efficiency of a model business plan divided into three steps, starting from a small scale in order to minimize the investment risk and financial burden, which is then gradually expanded. The business operation period was assumed to be 10 years (2012~2021), and the NVP (Net Present Value) and economic efficiency (B/C) for the operation period (10 years) were estimated for different loan size by dividing the size of external loan by stage into 80% and 40% based on the basic statistics secured through a site survey. Through the result of analysis, we can see that reducing the size of the external loan is an important factor in securing greater economic efficiency as, while the B/C is 1.79 in the case the external loan is 80% of the total investment, it is presumed to be improved to 1.81 when the loan is 40%. As the findings of this study showed that the economic efficiency of sturgeon aquaculture utilizing thermal effluent of power plant can be secured, it is presumed that regional development project items with high added value can be derived though this, and, in addition, this study will greatly contribute to reinforcement of the capability of local governments to cope with climate change.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.2
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• pp.167-181
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• 1995

An Ecocomplex is proposed for ecological design of the estuarine environment of Han River, which is designed upon an alternative mamagement concept of estuarine environment. The concept reveals interrelationships among estuary, delta region and urban inland with inputs/outputs and feedbacks among them. The Ecocomplex emphasizes an integration of wastewater treatment with aquaculture, agriculture and recreation, and carries out ecological treatment, recycling, and harvest processes. A module of wastewater treatment pond system is employed in the Ecocomplex, which treats a flow of 3,786 ㎥/day and is composed of a four-facultative-pond series. Treatment ponds stabilize wastewater discharged from the urban area, and concurrently produce algae for commercial or recreational fish farming. Effluent from treatment and fish ponds is reused for agricultural production. Through the waste-algae-fish-vegetable-recreation processes, wastewater from the urban settlement is recycled back to the urban ecosystem. This resource-conserving design approach can maintain a sustainable urban ecosystem, managing an estuarine environment more naturally, healthly, and economically.

• Journal of Aquaculture
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• v.13 no.2
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• pp.137-145
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• 2000

Capacity of water treatment of the three phase fluidized bed reactor as a biofilter in the seawater recirculating system was evaluated. The water treatment system consists of fluidized bed reactor for ammonia removal, cartridge filter for solid removal and ozone contactor for disinfection. Mean concentration of water quality parameters: COD, TAN, $NO_2$-N, $NO_3$-N, SS and alkalinity were 9.0, 0.22, 0.05, 20.0, 9.5 and 70.0 mg/l, respectively; the relevant values were 7.6 for pH and 3.64 NTU for turbidity. These indicate the maintenance of good water quality by the treatment system. The influent TAN loading rate in to the fluidized bed reactor ranged from 4.3 to 32.9 g/$m^3$/day, and averaged to 20 g/$m^3$/day. TAN removal efficiency of each phase of the fluidized bed reactor was 47-60%, indicating the effective ammonia removal. During operation the effluent of fluidized bed reactors also maintained the unionized ammonia nitrogen level below 0.002 mg/l.

• Journal of Aquaculture
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• v.12 no.4
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• pp.323-331
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• 1999

Most of channel fish farming in Alabama are still earthen pond style, and filled by rainfall and runoff. The water levels of ponds are maintained with stand-pipe, and the effluent from ponds very little discharged at usual time except ant heavy rains and crop season. Overflow from ponds following rains occurs mostly in winter and early spring when stream flows high. In this study to know how much effluents fish ponds affected to streams which are nearby ponds, a survey carried out on the variation of water quality of seven streams and effluents at heavy rains. Water samples were collected at 14 sites on upstream (did not affected by effluents) and downstream(being affect by effluents), and sampled monthly from August 1997 to August 1998. There were no clear trends of difference in most water quality variables between upstream and downstream of catfish farms during a year. The effluents from ponds after heavy rains were not highly polluted, but sometimes have elevated concentrations of TSS. Nitrogen content of effluents was higher than that of routine streams , but phosphorus was not clear. From this result suggest than the effluents from catfish farm are not having adverse impacts on stream water quality still yet .

• Journal of Aquaculture
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• v.6 no.4
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• pp.311-321
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• 1993

Ammonia accumulation is regarded as the limiting factor of the first priority in water qualities of aquatic culture systems. Nitrification efficiency and characteristics in seawater were evaluated using Rotating Biological Contactor (RBC) process as a part of the recycling water treatment facilities for marine fish culture system. Ammonia removal efficiency regarded 99.7 to $83.7\%$ at the ammonia surface loading rates of 48 to $393 mg/m^2$ -day. RBC process was able to withstand to the fluctuation of influent ammonia concentrations and loading and produced the stable effluent. The mathematical model on the fixed-film biological reactor developed by Kornegay seemed to be suitable to RBC process kinetic evaluation for the recycling water treatment of the marine fish culture system. Area capacity constant (P) and half-velocity constant (Ks) in the model were 0.188g/m^2$-day and 1.25mg/l, respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.1
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• pp.59-67
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• 2022

This study assessed the levels of water qualities and microbials contamination of inland olive flounder farms in Jeju in the summers from 2015 to 2017. Three farms (A-C) located in a concentrated area using mixing coastal seawater and underground seawater and one farm (D) located in an independent area using only coastal seawater were selected. Total ammonia nitrogen (TAN) reached a maximum of 0.898 ± 1.024 mg/L as N in the coastal seawater of A-C, which was close to the limit of the water quality management goal of the fish farm. TAN in the influent from A-C was up to three times higher than that of D, so that the discharged water did not spread to a wide range area along the coast and continued to affect the influent. TAN of the effluent in A-C increased by 2.7-4.6 times compared to the influent, resulting in serious self-pollution in the flounder farm. Heterotrophic marine bacteria in the influent of A-C was about 600 times higher than D, and the discharge of A-C was increased by about 30 times compared to the influent.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.3
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• pp.116-121
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• 2004

Treatability tests were conducted to study the feasibility of EMMC process as a recycling-water treatment system in high density seawater aquaculture farm. To study the effect of organic and ammonia nitrogen loading rate on system performance, hydraulic retention time was reduced gradually from 12hr to 10min. The conclusions are can be summarized as follows. When the system HRT was reduced from 12hr to 2hr gradually, there was little noticeable change(reduction) in ammonia nitrogen removal efficiencies. However, removal efficiencies were decreased dramatically when the system was operated under the HRT of less than 2hr. In case of organics(COD), there was no dramatic change in removal efficiencies depending on HRT reduction. COD removal efficiencies were maintained successfully higher than 9％ when the system was operated at tile HRT of 10 min. System performances depending on media packing ratio in the reactors were also evaluated. There were little differences in each reactor performances depending on media packing ratio in reactor when the reactors were operated under the HRT of longer than 1hr. However, differences in reactor performances were considerably evident when the reactors were operated under the HRT of shorter than 1hr. When comparing reactor performance among 25％, 50％,7 5％ packed reactor, it can be judged that media packing ratio more than 50％ plays no significant role in increasing reactor performance. For this reason, packing the media less than 50％ is more reasonable way in view of economic. Such a tendency shown in COD removal efficiencies well agreed with the variation of ammonia-nitrogen removal efficiencies according to the media packing ratio in reactors at each HRT. Difference in effluent ammonia-nitrogen concentration between 50％ media packing reactor and 75％ media packing reactor was negligible. When comparing with the results of 25％ packing reactor, difference was not so great.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.144-148
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• 1999

This study was conducted to test actual oxygen consumption rates of Nile tilapia (Oreochromis niloticus) at a commercial scale high density culture tank in the recirculating culture system, with a special emphasis on the oxygen consumption rate of this species with different daily feeding frequencies. Nile tilapia, an average of 400 g and a total wright of 390 kg, were stocked in a circular concrete tank of 2.9 m in diameter and 0.8 m in depth, in a recirculating culture system. The fish were fed commercial diet 1, 2, 5, and 9 times per day between 09:00 h and 19:00 h. feed was evenly supplied where the fish were fed more than once a day. Dissolved oxygen of influent and effluent water was monitored every 50 seconds by a computer with electrodes for 24 hours. The standard metabolic rate of tilapia was $39.31{\pm}4.4mg\;O_2/kg$ fish/hr in the present study. The maximum oxygen consumption was reached between 30 to 50 minutes after feeding. The maximum oxygen consumption levels of 1, 2, 5, and 9 feeding times per day were 161.2, 123.4, 111.1 and 111.1 mg $O_2/kg$ fish/hr, respectively. While the mean oxygen consumption levels of 1, 2, 5, and 9 feeding times per day were $79.9{\pm}21.5,\;81.3{\pm}14.8,\;84.2{\pm}9,9$ and $98,9{\pm}11.0mg\;O_2/kg$ fish/hr, respectively. These results show that oxygen consumption rates are not much different between the feeding frequencies. These results could be used to design to provide desirable oxygen supply system in the recirculating high-density tilapia culture system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.1
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• pp.97-106
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• 1996

Macroalgal community was analysed from December 1993 to October 1994 in Yonggwang vicinity, western coast of Korea. A total 51 species (12 green, 11 brown and 29 red algae) of marine algae were identified. Among four localities, the number of species observed was the highest as 34 species at Shimwon and the least as 31 species at Sunchanggum and Gamakdo. Seasonally, the number of species observed was the highest as 42 species in winter and the least as 18 species in summer. The species showing relatively high important value were Enteromorpha compressa, Sargassum thunbergii, Corallina pilulifera and Carpopeltis affinis, which were all common to four investigated localities. Seasonal and regional fluctuations of mean biomass was $66.0\~820.0\;g-wet\;wt/m^2$ at Hyanghado, $248.3\~886.3\;g-wet\;wt/m^2$ at Sunchanggum, $154.5\~510.2\;g-wet\;wt/m^2$ at Gamakdo and $85.0\~451.9\;g-wet\;wt/m^2$ at Shimwon, respectively. The flora investigated could be classified into six functional groups such as coarsely branched form $(41.2\%)$, sheet form $(25.5\%)$, filamentous form $(19.6\%)$, thick leathery $(7.8\%)$, crustous form $(3.9\%)$ and jointed calcarious form algae $(2.0\%)$. At the effluent area of the nuclear power plants, the algal composition of functional groups may affect species composition due to thermal pollution.