• Journal of Environmental Science International
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• v.26 no.1
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• pp.109-118
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• 2017

This study was conducted to investigate the effects of intermittent plasma and electrolysis treatments on lettuce (Lactuca sativa var. oak-leaf.), nutrient solution components ($NO_3{^-}-N$, $NH_4{^+}-N$, $PO{_4}^{3-}-P$, $K^+$, $Ca^{2+}$ and $Mg^{2+}$) and environmental parameters (electrical conductivity, total dissolved solids and pH). The recirculating hydroponic cultivation system consisted of planting port, LED lamp, water reservoir and circulating pump. Nutrient solution was circulated in the following order: reservoir ${\rightarrow}$ filtration-plasma or filtration-electrolysis ${\rightarrow}$ planting port ${\rightarrow}$ reservoir. The results showed that nutrient solution components and environmental parameters were changed by plasma or electrolysis treatment. Lettuce growth was not affected by the intermittent plasma or electrolysis treatment with 30 minutes or 90 minutes, respectively. The roots of the lettuce was damaged by excessive plasma and electrolysis treatment. Electrolysis treatment had greater effect on than plasma treatment because of the accumulation of high levels of TRO (Total Residual Oxidants).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.180-185
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• 1999

Rotating Biological Contactor (RBC) was tested for the treatment of artificial rearing water in n simulated aquaculture system. Performance of RBC on the removal of TAN and COD was evaluated by controlling hydraulic residence time (HRT). As HRT of RBC was increased, TAN removal rate ana removal efficiency of RBC and TAN concentration of rearing water were increased, but COD removal rate was decreased. Total alkalinity consumption rate was increased by increasing HRT of RBC. Ratio between total alkalinity consumption rate and TAN removal rate was 7.73. HRT for maintaining lowest TAN and COD concentration of artificial rearing water was 14,6 minutes and at that condition TAN and COD concentration of the water was 1.28 and $5.59 g/m^3$, respectively.

• Journal of Marine Life Science
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• v.2 no.2
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• pp.49-55
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• 2017

Four chemical treatments with hydrogen peroxide (H₂O₂), copper sulfate (CuSO₄), potassium permanganate (KMnO₄) and chlorine (Cl₂) were applied to the effluent pond water of a hybrid striped bass saltwater recirculating aquaculture system to compare their oxidation power. Four chemicals were applied at concentrations of 0 (control), 1, 5, 10 and 20 mg/l. An additional concentration of 40 mg/l was included in the chlorine treatment. Water samples from four hybrid striped bass ponds were tested with KMnO₄ and Cl₂. H₂O₂ did not reduce any of BOD, COD and chlorophyll-a, and copper sulfate was only effective on chlorophyll-a for the effluent pond. Removal efficiencies for chlorophyll-a by copper sulfate were 19.2%, 37.5%, 54.2% and 74.1% dose-dependently. Potassium permanganate effectively removed the BOD, COD and chlorophyll-a. The COD removal rates in four fish ponds varied from 15.9% to 31.6% at the concentration of 10 mg/l. Interestingly, Cl₂ did not reduce the BOD and COD at all, but the BOD and COD instead increased drastically with increasing the Cl₂ concentration. The pond water with the highest initial BOD and COD values among the fish ponds tested increased by 350% in the BOD and 150% in the COD at 20 mg/l. Furthermore, Cl₂ did not significantly reduce any types of solid matter in this study, while KMnO₄ seemed to reduce some extent volatile dissolved solid in the fish pond.

• Journal of Food Hygiene and Safety
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• v.7 no.2
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• pp.107.2-119
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• 1992

Fish pathology is one of the main scientific bases upon which this expansion in aquaculture has been dependent and requires a wide knowledge of the environmental constraints, the physiology and characteristic of the various pathogens, the responses of the host, and the methods by which they may be controlled. The primary disease and parasite problems in aquaculture animals related to viral, bacteria, fungal and protozoan epizootics. Parasitic nematodes, trematodes and cestodes are commonly found in aquaculture animals, but seldom are they present in concentrations sufficient to cause significant problems, When an epizootic does occur and chemical treatment is indicated, the appropriate chemical must be selected an properly applied. We have antibiotics, sulfa, nitrofuran and other chemicals for treatment of fish diseases, Some may be mixed with the feed during formulation, added to the pellets of feed as a surface coating, given in the form of an injection or used as a bath. Even though a drug or chemical has been officially approved for use in aquaculture, the substance should never be used unless there is a clear need, Some of the reasions for this view are as follows: (1) the constant use of antibiotics can leak to the development of resistant strains of bacteria, (2) biofilter efficiency may be impaired or destroyed by chemicals added to closed recirculating water systems, and(3) the injudicious use of chemical can have a damaging effect on the environment as well as on human.

• Ocean and Polar Research
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• v.32 no.3
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• pp.229-236
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• 2010

A study was conducted to investigate the effect of water temperature and photoperiod on the oxygen consumption of the fasting juvenile Pacific cod Gadus macrocephalus (mean body weight 79.9${\pm}$2.0 g) in order to quantify metabolic response of the species under given conditions. The oxygen consumption rate (OCR) of G. macrocephalus was measured under a combination of four different water temperatures (7, 10, 13 and $16^{\circ}C$) and three different photoperiods (24L:0D, 12L:12D and 0L:24D) with an interval of 5 minutes over a 24-hour period using a closed recirculating respirometer. Three replicates were set up in each treatment. OCRs increased with increased water temperatures under all photoperiod conditions (P<0.001). Mean OCRs at 7, 10, 13 and 16oC ranged from 793.7~1108.4, 1145.7~1570.3, 1352.8~1742.5 and 1458.2~1818.6 mg $O_2$ $kg^{-1}$ $h^{-1}$, respectively. Under all water temperature conditions except $7^{\circ}C$ (P<0.001), mean OCRs of G. macrocephalus were the highest in continuous light (24L:0D) followed by 12L:12D and 0L:24D photoperiods. Mean OCRs of fish exposed to the 12L:12D photoperiod were significantly higher during the light phase than during the dark phase under all temperature conditions (P<0.001). $Q_{10}$ values ranged from 3.19~5.13 between 7 and $10^{\circ}C$, 1.41~1.74 between 10 and $13^{\circ}C$ and 1.15~1.35 between 13 and $16^{\circ}C$, respectively. Based on overall results, water temperature, photoperiod and their combinations exerted a significant influence on the metabolic rate of juvenile cod. This study provides empirical data for estimating the amount of oxygen demand and managing the culture of cod under the given water temperatures and photoperiods.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.1
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• pp.21-26
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• 2002

The behavior of the biological water treatment process on start-up operation was evaluated in the integrated recirculating aquaculture system consisting of a double drain type rearing tank ($2.5 m^3$), a sedimentation tank, a floating bead filter, a foam separator and a rotating biological contactor. A system was stocked with nile tilapia (Oreochromis niloticus) at an initial rearing density of $2\%$ for 2 weeks for acclimated rotating biological contactor. The total ammonia nitrogen (TAN) level increased to $13.6 g/m^3$ on day 4 after adding feed and was decreased to $0.3 g/m^3$ on day 7. The total suspended solid was completely removed during overall experimental period.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.5
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• pp.469-475
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• 2002

The rotating biological contactor (RBC) was tested for treatment of aquacultural water in a pilot-scale recirculating aquaculture system. Performance of RBC on the treatment of nitrogen source such as total ammonia nitrogen (TAN), nitrite nitrogen and nitrate nitrogen and chemical oxygen demand (CODcr.) was evaluated. A system was stocked with nile tilapia at an initial rearing densities of $5\%$ and $7\%$ over 30 days. As increasing rearing density from $5\%$ to $7\%$, the TAN removal rates was increased from $39.4 g/m^3{\cdot}day$ to $86.0 g/m^3{\cdot}day$. But TAN removal efficiency was decreased from $24.5\%$ to $16.0\%$. The removal rate of $COD_Cr$ was higher than TAN. The RBC as an aerator was also evaluated for increasing dissolved oxygen concentration. For $5\%$ and $7\%$ of rearing density, the average aeration rate were $280 g/m^3{\cdot}day$ and $255 g/m^3{\cdot}day$, respectively.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 1992.07a
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• pp.7-19
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• 1992

Fish pathology is one of the main scientific bases upon which this expansion in aquaculture has been dependent and requires a wide knowledge of the environmental constraints, the physiology and characteristics of the various pathogens, the responses of the host and the methods by which they may be controlled. The primary disease and parasite problems in aquaculture animals relate to viral, bacterial, fungal and protozoan epizootics. Parasitic nematodes, trematodes and cestodes are commonly found in aquaculture animals, but seldom are they present in concentrations sufficinet to cause significant problems. When an epizootic does occur and chemical treatment is indicated, the appropriate chemical must be selected and properly applied. We have antibiotics, sulfa, nitrofuran and other chemicals for treatment of fish diseases. Some may be mixed with the fred during formulation, added to the pellets of feed as a surface coating, given in the dorm of an injection or used as a bath. Even though a drug or chemical has been officially approved for use in aquaculture, the substance should never be used unless there is a clear need. Some of the reasions for this view are as follows: (1) the constant use of antibiotics can lead to the development of resistant strains of bacteria, (2) biofilter efficiency may be impaired or destroyed by chemicals added to closed recirculating water systems, and (3) the injudicious use of chemicals can have a damaging effect on the environment as well as on human.

• Applied Biological Chemistry
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• v.41 no.2
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• pp.181-186
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• 1998

The effects of sewage treatment on characteristics of sludge as a composting material were investigated for a year during the initial operation at the full-scale Chunan sewage treatment plant. Due to the shortage of design capacity of belt press, a sludge dewatering unit, non-volatile solids were recirculating and concentrating in the treatment plant, resulting in an increase of MLSS and a decrease in F/M ratio at the activated sludge system. Special attention is required for long term operations since the increase of non-volatile solids in the plant would deteriorates the treatment efficiency. The sewage sludge of the Chunan sewage treatment plant showed 79.5% of water content, 11.6% of organic content, and C/N ratio of 6.1, and contained As 1.8 mg/kg, Cd 27 mg/kg, Hg <0.1 mg/kg, Pb 54 mg/kg, T-Cr 370 mg/kg, and Cu 1,100mg/kg of heavy metals. In order to be used as raw material for optimum composting, the sewage sludge requires bulking agents for moistrure/porosity control and a carbon source for adjusting C/N ratio. However, the sewage sludge is not adequate as a soil conditioner after composing due to a high content of heavy metals. If the sewage sludge has to he used as a soil conditioner after composting, it as required to identify and remove tire industrial wastewater portions in tire influent of the plant since heavy metals in the influent were mostly concentrated in dewatered sludge.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.816-822
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• 1997

The immobilization of a microorganism has been rapidly progressed with the development of biotechnology in recent years. Although it has been used as a tool to isolate products from biological media in various areas, it has not yet been practiced in the treatment of waste water. In this paper, we suggest a possibility to apply the immobilization technique In the recirculating aquaculture system. We examined the ability of $NH_4^+$ removal by nitrifier consortium immobilized in $Ba^{++}-alginate$, k-carrageenan and agar bead at the concentration of 50 g/L, respectively. In order to use the immobilized nitrifier consortium as media in the fludized bed reactor, the strength of bead was measured. $Ba^{++}-alginate$ as a support material showed higher strength of bead. Also, the nitrifier consortium immobilized in $Ba^{++}-alginate$ showed higher nitrification activity that could remove 20 mg/L ammonium ion than those immobilized in other two support materials, carrageenan and agar. The immobilized nitrifier consortium showed better nitrification activity than free nitrifier consortium.