• 생태와환경
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• 제46권2호
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• pp.205-214
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• 2013

영산강 하구에서 담수 유입이 부유생태와 수질에 미치는 영향을 파악하기 위해 국가해양환경측정망 장기자료(1999~2008년)인 클로로필 a와 수질 항목들에 대한 계절적, 공간적 변화와 장기변동 추세를 분석하였다. 분석결과, 여름철 (8월) 영산강 방조제 인접정점의 염분은 조사기간 중 가장 낮은 분포를 보였고, 영양염류와 클로로필 a는 전반적으로 높은 분포를 나타냈다. 영산강 담수유입의 지시인자인 표-저층의 염분차 (${\Delta}salinity$)와 영양염류, 클로로필 a는 유의한 양의 상관성을 나타냈으나, 지난 10년동안 담수 방류량은 감소하는 추세를 보였고, 영양염류, 클로로필 a는 전반적으로 증가하는 경향을 나타냈다. 이러한 결과는 영산강 하구 해역 영양염의 공급원이 담수유입뿐만 아니라 인근 지역의 발달에 따른 점오염원 증가 등의 추가적인 요인이 존재할 가능성을 제시한다. 따라서 영산강 하구 주변 해역의 부영양화 방지를 위해서는 영산강 방조제의 방류와 연관한 수질개선방안 마련과 더불어 인근 지역의 점 오염원 파악 및 관리가 병행되어야 할 것으로 사료된다.

• 한국환경과학회지
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• 제23권6호
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• pp.1165-1173
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• 2014

For the field application of dielectric barrier discharge plasma reactor in nutrient solution culture, a filtration-DBD (dielectric barrier discharge) plasma reactor was investigated for the Ralstonia solanacearum which causes bacterial wilt in aquiculture. The filtration-DBD plasma reactor system of this study was consisted of filter, plasma reactor, reservoir. The DBD plasma reactor consisted of a quartz dielectric tube, discharge electrode (inner) and ground electrode (outer). The experimental results showed that the inactivation of R. solanacearum with filter media type in filter reactor ranked in the following order: anthracite > fiber ball > sand > ceramic ball > quartz ceramic. In filtration + plasma process, disinfection effect with the voltage was found to small. In disinfection time of 120 minutes, residual R. solanacearum concentration was 1.17 log (15 CFU/mL). When the continuous disinfection time was 120 minute, disinfection effect was thought to keep the four days. In sporadic operation mode of 30 minutes disinfection - 24 hours break, residual R. solanacearum concentration after five days was 0.3 log (2 CFU/mL). It is considered that most of R. solanacearum has been inactivated substantially.

• 해양환경안전학회지
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• 제20권3호
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• pp.270-276
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• 2014

Seasonal characteristics of water and sediment qualities and potential effects of the freshwater discharge from a small tide embankment interior in a coastal area in Goheung county were investigated from May to September in 2012. Chemical oxygen demand values (COD) were mostly higher than 2 mg/L in summer ebb tide, which exceed the standard value of water quality criteria II of acceptable level for aquaculture activities. Nitrogen and phosphorus were found as the limiting nutrients for algae growth in summer and fall and in spring, respectively. Nitrogen was the limiting nutrient for diatom growth in the whole studied period. The sudden high values of COD, ammonia, dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) were found in water sample collected from station 5 which located in front of the tide embankment sluice gate during spring ebb tide. The freshwater discharge form the tide embankment interior maybe affected the survey areas during a short time interval. Mean values of eutrophication index of the surveyed coastal region in spring, summer and fall were all bigger than 1. Water quality was mostly considered at level II which acceptable for aquaculture activities. Sediment quality in this study was generally in the range of standard for fisheries environment.

• Journal of Biosystems Engineering
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• 제22권4호
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• pp.469-478
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• 1997

This study was conducted to develop an automatic nutrient-solution mixing system for small-scale sewers. The nutrient-solution mixing system consisted of a low-cost and precise metering device and data acquisition ＆ control system with a personal computer. and, the metering device was composed of three parts those were supply pumps, metering cylinders and venturi tube. The system controlled electric conductivity(EC) and pH of nutrient-solution based on the time-based feedback control method with the information about temperature, EC, and pH of the nutrient-solution. The performance of the nutrient-solution mixing system was evaluated through the control of EC and pH while compared with those of commercial system. Also an experimental cultivation of tomato was conducted to verify and to improve the developed system. Results of this study were as follows. 1. The correlation coefficient of meteing device between the flow rate and operating time was 0.9999, and the linear reuession equation computed was y=21.759x, where y is the discharge($g$) and x is the operating time(s). 2. Calculated errors for the developed metering device and two commercial pump were $\pm$0.3% $\pm$2.45% and $\pm$1.38 % FS error respectively. 3. An automatic nutrient-solution mixing system based on a low-cost and precise metering device was developed. 4. The full scale errors of the developed system in controlling EC and pH at 23$\pm$1$^{\circ}C$ were $\pm$0.05mS/cm and $\pm$0.2, respectively 5. When using the commercial system, the controlled values of EC and pH of the 500 $\ell$ of water were 1.29 mS/cm and 6.1 pH for the setting points of 1.4 mS/cm and 6.0 pH respectively at 23$pm1^{\circ}C$. 6. The developed nutrient-solution control system showed $\pm$0.05 ms/cm of deviation from the setting EC value over the experimental cultivation period. 7. The deviation from the average values of Ca and Mg mass content in the several nutrient-solution were 0.5% and 1.8% respectively.

• Ocean Science Journal
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• 제43권4호
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• pp.223-232
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• 2008

In order to determine the temporal and spatial variations of nutrient profiles in the shallow pore water columns (upper 30 cm depth) of intertidal sandflats, we measured the salinity and nutrient concentrations in pore water and seawater at various coastal environments along the southern coast of Korea. In the intertidal zone, salinity and nutrient concentrations in pore water showed marked vertical changes with depth, owing to the active exchange between the pore water and overlying seawater, while they are temporally more stable and vertically constant in the sublittoral zone. In some cases, the advective flow of fresh groundwater caused strong vertical gradients of salinity and nutrients in the upper 10 cm depth of surface sediments, indicating the active mixing of the fresher groundwater with overlying seawater. Such upper pore water column profiles clearly signified the temporal fluctuation of lower-salinity and higher-Si seawater intrusion into pore water in an intertidal sandflat near the mouth of an estuary. We also observed a semimonthly fluctuation of pore water nutrients due to spring-neap tide associated recirculation of seawater through the upper sediments. Our study shows that the exchange of water and nutrients between shallow pore water and overlying seawater is most active in the upper 20 cm layer of intertidal sandflats, due to physical forces such as tides, wave set-up, and density-thermal gradient.

• 한국수산과학회지
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• 제22권6호
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• pp.397-407
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• 1990

James강 하구에서 1986년 7월부터 1987년 8월까지 약 1달 간격으로 식물 부유생물의 현존량에 대한 조사를 하였다. 강 유입량이 적은 여름과 가을에 담수와 해수가 만나는 저염분 지역에서 많은 양의 식물 부유생물이 출현하였다. 이 많은 양의 출현은 영양염, 조석 그리고 수온과는 관계없이 estuarty의 순환에 의한 규조류의 축적에 기인한 것으로 사료된다.

• 한국토양비료학회지
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• 제49권4호
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• pp.310-317
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• 2016

This study aimed to evaluate the nutrient load balance from rice paddy fields with different topographies, alluvial plain and local valley. Continuous monitoring from May to September, 2013 was conducted for water quantification and qualification from alluvial plain in Yeoju region (32 ha) and local valley in Jincheon region (24 ha). The discharge rates of T-N from the alluvial plain were 57.2, 5.84, 22.7, and $5.20kg\;ha^{-1}$ for irrigation, precipitation, drainage, and percolation, respectively. In case of local valley, T-N loads were 34.6, 4.73, 21.1, and $4.15kg\;ha^{-1}$ for irrigation, precipitation, drainage, and percolation, respectively. In contrary, the T-P loads from the alluvial plain were 2.23, 2.22, 2.54, and $0.41kg\;ha^{-1}$ for irrigation, precipitation, drainage, and percolation, respectively. In case of local valley, T-P loads were 1.44, 1.57, 1.82, and $0.34kg\;ha^{-1}$ for irrigation, precipitation, drainage, and percolation, respectively. The nutrient contents in drainage water were influenced by the amount of waters, rainfall, and surface drainage water. The Pearson correlation analysis showed that rainfall was significantly correlated with nutrient loads from July to August due to the amount of runoff in local valley paddy field, and irrigation was related with nutrient loads of drainage from July to August. This study showed that paddy rice farming in alluvial plain and local valley might be beneficial to water quality protection.

• 유기물자원화
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• 제29권1호
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• pp.19-27
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• 2021

양액재배는 기존 비닐하우스 안의 토양재배 방식에서 물이나 배지에 작물을 심고 생육에 필요한 양분(비료)을 녹인 양액을 공급하여 재배하는 방식으로 기존 시설재배 방식에서 영농기술이 발전하여 양액재배는 작물의 생산성을 극대화할 수 있는 큰 장점을 가지고 있다. 본 연구는 폐양액이 다량의 비료 물질을 함유하고 있기에 하천으로 유입되면 인근 하천을 오염시키며, 양액재배에 사용되고 폐기되는 폐배지, 폐작물의 처리에 대한 문제점을 제시하고 있다. 또한, 처리시 처리비용의 발생과 현재 국내 양액재배 농장의 대부분이 비순환식 양액재배 시스템을 사용하여 배출되는 양액의 잔여비료로 인한 환경오염 및 비료의 불필요한 과다 사용 문제점을 지적하는 선행연구를 바탕으로 사전조사와 실험을 진행하였다. 현재 양약재배 비순환식 시스템 재배방식 농장에서 발생하는 폐양액, 폐배지, 폐작물이 농장 주변 환경에 미치는 영향을 수질, 토양분석 결과 수치를 통해 규명하고자 현장자료 연구를 진행하였다. 현장 수질, 토양분석을 위해서 지역별 양액재배 5개 농가의 작형, 양액재배 시스템를 확인하였으며, 강원 C지역 토경재배 3개 농장의 작형, 양액재배 시스템 농장 현장을 방문하여 농장의 시설내·외부 수질, 토양 샘플을 채취하였다. 추가적으로 폐작물 야적지에서 발생되는 침출수 및 토양샘플을 채취하여 수질, 토양분석을 하였다. 연구 결과 비순환식 시스템 재배방식 농장에서 발생되는 폐양액의 평균 total nitrogen(TN) 농도는 402 mg/L 이였고, total phosphate(TP)의 경우 77.4mg/L 이였으며, 이는 환경정책기본법 시행령상 하천의 생활환경 TP기준 993.7배 초과한 수치였다. 또한, 물환경보전법의 산업폐수 배출기준 TN기준 6~19배, TP기준 2~27배 초과한 수치결과를 확인하였다. 폐작물 야적지에서 발생된 침출수의 경우 환경정책기본법 시행령상 하천의 생활환경 COD 기준 11,828배 초과, TP기준 395~2663배 초과한 수치이며, 물환경보전법의 산업폐수 배출기준 TN기준 788배, TP기준 5배 초과한 수치결과를 확인하였다. 비순환식 양액재배에서 발생하는 폐양액, 폐배지, 폐작물이 환경에 미치는 영향에 대한 더 정밀한 연구를 위해 전국 양액재배 농가수(호), 재배면적(ha)를 기준으로 하여 양액재배면적이 넓은 지역 도출해내어야 한다. 이를 통해 넓을 지역의 양액재배 시설 주변 소하천을 중심으로 계절적 요인, 기후 요인, 날씨 요인, 재배면적, 재배지역, 농가 재배특성 등의 다양한 요인을 고려한 수질 및 토양 샘플링 채취와 분석에 관한 추가 연구가 필요할 것으로 판단된다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.521-526
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• 1998

This study was initiated to build runoff plots, install soil and water quality monitoring systems and collect background data from the plots and soils to assess runoff the nonpoint source pollution and soil physical change in mountainous soils. Eleven 3 $\times$ 15 m runoff plots and monitoring systems were installed at a field of National Alpine Agricultural Experiment Station to monitor soil physical change, and discharge of nonpoint source pollutant. Corn and potato were cultivated under different fertilizer, tillage and residue cover treatments. The soil has a single-layered cluster structure that has a relatively good hydrologic properties and can adsorb a large amount of nutrient. 11 runoff plots were treated and monitored with respect to physical property of the soil, runoff and sediment discharge.

• 한국기계기술학회지
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• 제13권1호
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• pp.31-40
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• 2011

This study was conducted to research how UCD(Ultra Constant Discharge) lamp lighting affects plant cultivation. To get the results within a short time, lettuce seedling was selected as a plant and nutrient hydroponic beds were used in a dark room for 100% artificial lighting. Two beds were installed for same distance lighting condition with UCD lamp and Hi-pressure Sodium lamp each and another two beds were installed for same light intensity condition with each type of lamp. After 15 days of cultivation, for both conditions, the yields under UCD lamp were weighed more than that under Hi-pressure Sodium lamp. The result can be analyzed that the spectrum of UCD lamp having near sunlight characteristic is much superior to that of Hi-pressure Sodium lamp having a line spectrum characteristic on yellow and red wavelengths for plant cultivation.