• Journal of Biosystems Engineering
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• 제15권2호
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• pp.123-133
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• 1990

Thermal performance of a solar heating plastic greenhouse designed for a hydroponic system was studied. The system was constructed with the air-water heat exchanger and thermal storage tank that were combined with hydroponic water beds. Experiments were carried out to investigate the daily average heat stored and released in thermal storage tank, average solar energy collection efficiency, average coefficient of performance, average oil reduction factor of thermal storage system, and the heat transfer coefficient during the nighttime in plastic greenhouse. The results obtained in the present study are summarized as follows. 1. Daily average heat stored in thermal storage tank and released from the thermal storage tank was 1,259 and $797KJ/m^2$ day, respectively. 2. The average solar energy collection efficiency of thermal storage tank was 0.125 during the experiment period. And the average coefficient of performance of thermal storage system in plastic greenhouse was 3.6. 3. The average oil reduction factor of thermal storage system and the heat transfer coefficient during the nighttime in plastic greenhouse were found to be 0.52 and $4.3W/m^2\;hr\;^{\circ}C$, respectively.

• 한국환경과학회지
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• 제30권12호
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• pp.1005-1014
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• 2021

Organic contaminants can be released into water environments due to chemical accidents and exist as dissolved and non-aqueous phase liquids (NAPL). Fenton oxidation was tested for bisphenol A and nitrobenzene as model organic contaminants in dissolved and NAPL states. Fenton oxidation was successfully applied for both of the dissolved and NAPL states of the two pollutants and the results indicated that a quick treatment was needed to reduce the risk from a chemical accidents instead of carrying out oxidation after the contaminants dissolve in water. A set of Fenton reactions were tested under seawater conditions because chemical accidents often occurs in the ocean. Chloride ions act as radical scavengers and inhibit Fenton oxidation. The reaction rate is inversely proportional to salt contents and the reduced reaction rate can be compensated by increasing the quantity of the oxidizing agents. The current study showes that Fenton oxidation could be applied as a quick treatments for organic contaminant in dissolved and NAPL state organic contaminants released as a result of leaks or chemical accidents.

• 한국습지학회지
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• 제2권1호
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• pp.69-85
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• 2000

Wetlands are generally thought to be among the most fertile and productive ecosystems of the world. They provide a variety of ecological functions to the landscape. In recent years there has been considerable research activity to generate more scientific documentation on the ecological functions of wetlands. Many pollutants released to the environment settle and accumulate in the silt and mud called sediment on the bottoms of wetlands. Contaminated sediment can cause adverse effects to aquatic organism and eventually to ecological system. Sediment toxicity test with water fleas has been done by standardized preparation method of pore and elutriate water methods described in the literature for the need to protect Woopo wetlands. The results of Daphnia magna, Ceridaphnia dubla and Simocephalus sp. toxicity test were compared and discussed in terms of the relative sensitivity and discrimination abilities with both pore and elutriate water obtained from the sediments of Woopo wetlands.

• 한국양식학회지
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• 제14권2호
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• pp.67-71
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• 2001

Phosphorus is an essential element for growth and metabolism in fish. However high levels of phosphorus in the feed can lead to poor water quality of pond, and can also be a potential source of pollution, when pond water is released to the environment. In this study phosphorus supplemented diets containing 0.0, 0.9 or 1.9% of (dicalcium) phosphate were offered to channel catfish and changes in water quality of ponds and phosphorus levels in fish were measured. Higher level of (1.9%) supplementation of phosphorus in diet resulted in higher concentration of T-P and SRP in pond waters. Also it produced negative effects on fish production by lowering feed coefficient and rate of increment in body weight. Surplus phosphorus can affect fish growth and water quality of pond.

• 한국토양비료학회지
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• 제33권2호
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• pp.109-113
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• 2000

폐지섬유 내로 요소를 침적시켜 폐지섬유 내에 침투된 요소성분이 토양 중에서 서서히 용출됨으로써 작물의 요구에 알맞게 양분을 서서히 공급함과 동시에 이들 폐지섬유도 분해되도록 개발된 완효성 요소비료(시제품)의 화학적 특성, 미세구조 및 수중 질소용출량을 조사한 바 얻어진 결과를 요약하면 시제품의 화학적 조성은 질소가 26%, 인산, 가리는 각각 0.04. 0.01%였으며, 함유된 유해성분들 중에 크롬, 구리 납 등은 검출되었지만 비료공정규격 이하였으며, 비소와 카드뮴은 검출되지 않았다. 폐지섬유와 시제품의 구조를 주사전자 현미경(SEM)으로 확대해 보면 폐지섬유의 내부에는 빈 공간이 보이지만, 시제품에서는 폐지섬유의 셀룰로오스성 -OH기에 극성의 요소성분이 달라붙어 있었으며, 세포벽에 요소가 침적된 모습이 보인다. 시제품의 수중 질소용출량은 12시간까지는 60.4%로 급격하게 용출량이 많았으나, 그 후 서서히 용출되어 72시간에 75%까지 용출되었다.

• 한국환경과학회지
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• 제9권6호
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• pp.505-509
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• 2000

The purpose of this study was to evaluate the effects of $Ca(OH)_2$ and $CO_2$ additions on the corrosion of metal coupons(ductile iron, galvanized steel, copper and stainless steel). Corrosion rate and released metal ion concentration of ductile iron and galvanized steel decreased by adjusting alkalinity, calcium hardness and pH with $Ca(OH)_2$ & $CO_2$ additions on copper and stainless steel were less than those on ductile iron and galvanized steel. When ductile iron coupon was exposed to water treated with Ca(OH)$_2$&$CO_2$, additions, the main components of corrosion product formed on its surface were $CaCO_3$ and $Fe_2 O_3 or Fe_2 O_4$ which often reduce the corrosion rate by prohibiting oxygen transport to the metal surface.

• 농촌계획
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• 제11권4호
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• pp.25-31
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• 2005

The present study was carried out to investigate the P fractions of surfical sediment of Dongjin sea area. Furthermore, potential released loading of adsorbed and non-apatite inorganic phosphorus were investigated in the sediment of Dongjin sea area. The contents of phosphorus fractions of the surficial sediment in Dongjin sea area were adsorbed-P 0.06%, nonapatite inorganic-P 13.02%, apatite-P 60.22%, and residual-P 26.70%. The most abundant fraction was apatite-P, residual-P, nonapatite inorganic-P, and adsorbed-P followed it. Potential released loading of adsorbed and non-apatite inorganic phosphorus surveyed 2.6 and 597ton respectively. These results show that sediment-managing and interception from external pollution are needed for water environmental maintenance of Dongjin sea area.

• Journal of the Korean Wood Science and Technology
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• 제42권5호
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• pp.597-604
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• 2014

Laboratory-scale landfills (simulated landfills) were designed to determine the formaldehyde released into air and leachate from medium density fiberboard (MDF). Simulated landfills were constructed using cylindrical plastic containers containing alternating layers of soil and MDF for a total of five layers. The highest concentration of formaldehyde was found in the air and leachate from the MDF only treatment compared to treatments containing MDF and soil. At the end of the study (28 days), formaldehyde concentrations in air and leachate from treatments containing MDF and soil decreased by 70 percent and 99 percent, respectively, while the treatment containing MDF only still released formaldehyde into the air and leachate. Therefore, waste MDF after storing 4 weeks in water may be recycled as compost or mulch based on formaldehyde leaching. Also, these data indicate soil restricts formaldehyde release into air and leachate and provides new information about the fate of wood-based composite waste containing UF resin disposed in landfills.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.424-427
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• 2006

Soil contamination with petroleum oil around a military army was investigated. It showed that soils of a riverside highland, an entrance of the military army, and nearby roads were contaminated with total petroleum hydrocarbons (TPH) released from the military army to the depth of approximately 2 m. The measured concentrations were as high as 15,277 mg/kg. A wide range of soil in the riverside highland was contaminated by the movement of oil to the surface soil, which occurred with the vertical movement of groundwater table caused by the change of river water level and groundwater level. Spilled petroleum oil components were released into Wonju Stream by the increase of hydraulic conductivity and the groundwater flow.

• 한국안전학회지
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• 제25권6호
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• pp.210-215
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• 2010

In this study, when the forest fire occurred, in order to estimate greenhouse gas emissions, tree glow in Gangwon Youndong area, Juglans mandshurica, Alnus japonica, Acer palmatum of carbon dioxide and carbon monoxide emissions were about. Water content were measured before the experiment, Juglans mandshurica 196.24%, Alnus japonica 169.17% Acer palmatum 210.10% moisture content showed a big difference, Living leaves of Acer palmatum were a lot of moisture. Also, 50g weight of carbon dioxide on the Juglans mandshurica 53.3644g, Alnus japonica 49.4256g, was released about Acer palmatum 51.3394g, Juglans mandshurica living leaves were the most carbon dioxide emissions. Carbon monoxide emissions result, About weight 50g Juglans mandshurica 1.5329g, Alnus japonica 1.7189g, 2.5002g about Acer palmatum was released, Acer palmatum living leaves were the most carbon monoxide emissions.