• 제목/요약/키워드: Phosphorus budget

검색결과 31건 처리시간 0.026초

하천형 호수인 팔당호 수질의 시공간적 특성 (Temporal and Spatial Characteristics of Water Quality in a River-Reservoir (Paldang))

  • 공동수;민정기;변명섭;박혜경;천세억
    • 한국물환경학회지
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    • 제34권5호
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    • pp.470-486
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    • 2018
  • This study is to investigate the allochthonous load and water quality of a typical river-reservoir, Paldang during spring (March ~ May) of 17 years (2001 ~ 2017). Phosphorus loading from point sources seems to have been reduced by 74 % in the 2010s. As a result, trophic state of the Paldang reservoir, eutrophic during the 2000s, has returned to the lmesotrophic state. Along with decrease in phosphorus concentration, standing crops of algae (Chl.a) decreased, and concentration of biodegradable organic material decreased to the past level. Concentration of total suspended solids has decreased, and it is due to the decrease of phytoplankton standing crops since the mid-2000s. As transparency increased, it is estimated that euphotic area increased by 22 % and euphotic capacity expanded by 27 %. In the river/transition zone of Paldang, concentration of organic matter increases slightly due to algal growth, but concentration of all water quality items decreases in the lacustrine zone. Although algal growth rate revealed positive correlation with concentration of phosphorus, it was insignificant. Algal growth appeared to be dependent on renewal of phosphorus by flow, than either flow rate or phosphorus concentration. The empirical model including inflow phytoplankton concentration fit well with observed values, and indicates the Paldang reservoir is greatly influenced by allochthonous loads.

Hiroshima만에서의 질소, 인의 분포 및 수지 (Distributions and Budgets of Nitrogen and Phosphorus in Hiroshima Bay)

  • 김도희
    • 한국해양환경ㆍ에너지학회지
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    • 제2권1호
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    • pp.74-89
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    • 1999
  • 1991년 1월부터 1993년 12월에 걸쳐 Hiroshima만 내부와 만 중앙부에서 질소 및 인의 분포와 수지를 조사했다. 총질소 및 총인의 유입 부하량은 각각 870 tonN/month과 129 tonP/month으로 그중 79%의 총질소 및 84%의 총인이 Hiroshima만 해역으로 유입되고 있었다. 유입 하천수중의 평균 TN/TP의 원자비는 15, DIN/DIP 원자비는 21이었다. 만 전체에서의 PON/POP의 원자비는 8~14 (평균 11)이었고 DIN/DIP의 원자비는 8~18 (평균 12)였다. 각 해역간의 해수 교환량으로부터 계산된 총질소와 총인의 교환량은 585 tonN/month와 106 tonP/month이 만 내부로부터 만 중앙부로 유출되고, 만 중앙부에서는 62 tonN/month와 107 tonP/month가 만 외부 해역으로 유출되고 있는 것으로 평가되었다. 질소 및 인의 수지로부터 계산된 총질소 및 총인의 침강량은 만 전체에서는 각각 9.83 gN/m²ㆍyr와 0.27 gP/m²ㆍ yr였고, 만 내부에서는 각각 8.54 gN/m²ㆍyr와 0.25 gP/m²ㆍyr 였으며, 만 중앙부에서는 각각 10.1 gN/m²ㆍyr와 0.27 gP/m²ㆍyr로 계산되었다. Hiroshima 만 내의 질소 및 인의 체류시간은 각각 112일로 계산되었다.

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하천형 저수지의 단순 물질수지 모델링 (Simple Material Budget Modeling for a River-Type Reservoir)

  • 윤성규;공동수;배우근
    • 한국물환경학회지
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    • 제26권3호
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    • pp.420-431
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    • 2010
  • 하천형 저수지인 팔당호의 건기시 수질을 모의하기 위하여 단순 물질수지 모델을 개발하였다. 대상 물질은 총인 (TP), 클로로필${\alpha}$ ($Chl.{\alpha}$), 5일 생물학적 산소 요구량 (BOD) 화학적 산소요구량 (COD)이었다. 모델은 지난 20년간의 실측치를 잘 재현하였으며 유기물질의 성인을 밝히는데 이용될 수 있었다. 모델을 통하여 분석한 결과, 팔당호에서 인에 대한 조류의 이용성을 결정하는 임계 수리부하는 약 $1.5m\;d^{-1}$로 나타났다. 팔당호의 $Chl.{\alpha}$, COD, BOD 농도는 임계부하보다 작은 수리부하의 조건에서 생산과 호흡 및 침전과 같은 조류의 변화에 민감하게 반응하였다. 최근 유기오염 저감을 위한 중앙정부와 지방정부의 강도 높은 노력에도 불구하고 팔당호의 수질은 크게 개선되지 않았으며 오히려 COD 농도는 증가하였다. 모델 해석을 통하여 이는 조류 생산량의 증가와 아울러 비점오염원 등에서 외래성 부하가 증가하였기 때문인 것으로 나타났다. 특히 2000~2007년 기간의 조류 기원성 유기물 농도는 전체 유기물 농도의 절반에 해당하는 것으로 추정되었으며, 이는 1988~1994년 기간에 비하여 2.5배, 1995~1999년 기간에 비하여 1.3배에 달하는 수준이었다. 이러한 연구의 결과는 팔당호의 수질개선을 위해서는 조류 발생을 억제하는 것이 필요함을 시사하는 것이었다.

The control of point and non-point source nitrogen to prevent eutrophication of the Nakdong River basin, Korea

  • Kwak, Sunggue;Yun, Zuwhan
    • Membrane and Water Treatment
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    • 제11권5호
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    • pp.345-351
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    • 2020
  • Eutrophication of surface waters is commonly caused by excessive inputs of nutrients such as nitrogen and phosphorus. Nakdong River basin was chosen as the study area to investigate the effect of point and non-point source pollution of nitrogen on eutrophication in water body. Non-point source inputs of nitrogen accounted for approximately 84% in the total nitrogen input of the upper Nakdong river watershed, which mainly consists of agricultural land and forests. However, point source inputs of nitrogen accounted for 58~85% in the total nitrogen input of the middle and lower watersheds, including urban area. Therefore, for watershed near urban area, control of point source inputs of nitrogen may be an optimal method to control eutrophication. In this respect, the enforcing reduction of nitrogen in the final effluent of wastewater treatment facilities is needed. On the other hand, to enact more stringent nitrogen regulations, the LOT (limit of technology) and environmental impact should be considered. In this study nitrogen data were analyzed to propose new nitrogen regulations.

PSG막의 급속열처리 방법을 이용한 LDD-nMOSFET의 구조 제작에 관한 연구 (A Study on the Structure Fabrication of LDD-nMOSFET using Rapid Thermal Annealing Method of PSG Film)

  • 류장렬;홍봉식
    • 전자공학회논문지A
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    • 제31A권12호
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    • pp.80-90
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    • 1994
  • To develop VLSI of higher packing density with 0.5.mu.m gate length of less, semiconductor devices require shallow junction with higher doping concentration. the most common method to form the shallow junction is ion implantation, but in order to remove the implantation induced defect and activate the implanted impurities electrically, ion-implanted Si should be annealed at high temperature. In this annealing, impurities are diffused out and redistributed, creating deep PN junction. These make it more difficult to form the shallow junction. Accordingly, to miimize impurity redistribution, the thermal-budget should be kept minimum, that is. RTA needs to be used. This paper reports results of the diffusion characteristics of PSG film by varying Phosphorus weitht %/ Times and temperatures of RTA. From the SIMS.ASR.4-point probe analysis, it was found that low sheet resistance below 100 .OMEGA./ㅁand shallow junction depths below 0.2.mu.m can be obtained and the surface concentrations are measured by SIMS analysis was shown to range from 2.5*10$^{17}$ aroms/cm$^{3}$~3*10$^{20}$ aroms/cm$^{3}$. By depending on the RTA process of PSG film on Si, LDD-structured nMOSFET was fabricated. The junction depths andthe concentration of n-region were about 0.06.mu.m. 2.5*10$^{17}$ atom/cm$^{-3}$ , 4*10$^{17}$ atoms/cm$^{-3}$ and 8*10$^{17}$ atoms/cm$^{3}$, respectively. As for the electrical characteristics of nMOS with phosphorus junction for n- region formed by RTA, it was found that the characteristics of device were improved. It was shown that the results were mainly due to the reduction of electric field which decreases hot carriers.

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Groundwater and Surface Water Hydrology in the Lake Rotorua Catchment, New Zealand, and Community Involvement with Lake Water Quality Restoration

  • White, Paul A.;Hong, Timothy;Zemansky, Gil;McIntosh, John;Gordon, Dougall;Dell, Paul
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2007년도 학술발표회 논문집
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    • pp.8-14
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    • 2007
  • Water quality in Lake Rotorua, New Zealand, deteriorated since the 1960s because of excessive phytoplankton growths due principally to increasing nitrogen and phosphorus in the lake waters. Nutrient concentrations in eight of the nine major streams feeding Lake Rotorua have increased since 1965. The groundwater system has a key role in the hydrology of the Lake Rotorua catchment and the groundwater system is probably the control on the time delay between intensification of agricultural land use and response of surface water quality. All major, and many minor streams, in the catchment are fed by springs. Two lithological units are most important to groundwater flow in the Lake Rotorua catchment: Mamaku Ignimbrite, erupted in about 200,000 years ago and Huka Formation sediments which filled the caldera left by the Mamaku Ignimbrite eruption. Rainfall recharge to groundwater in the groundwater catchment of Lake Rotorua is estimated as approximately 17300 L/s. A calibrated steady-state groundwater flow model estimates that approximately 11100 L/s of this flow discharges into streams and then into the lake and the balance travels directly to Lake Rotorua as groundwater discharge through the lake bed. Land use has impacted on groundwater quality. Median Total Nitrogen (TN) values for shallow groundwater sites are highest for the dairy land use (5.965 mg/L). Median TN values are also relatively high for shallow sites with urban-road and cropping land uses (4.710 and 3.620 mg/L, respectively). Median TN values for all other uses are in the 1.4 to 1.5 mg/L range. Policy development for Lake Rotorua includes defining regional policies on water and land management and setting an action plan for Lake Rotorua restoration. Aims in the action plan include: definition of the current nutrient budget for Lake Rotorua, identification of nutrient reduction targets and identification of actions to achieve targets. Current actions to restore Lake Rotorua water quality include: treatment of Tikitere geothermal nitrogen inputs to Lake Rotorua, upgrade of Rotorua City sewage plant, new sewage reticulation and alum dosing in selected streams to remove phosphorus.

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WASP5 모형에 의한 새만금호의 수질 매개변수 추정 (Estimation on Parameters of Water Quality in the Saemanguem Lake by WASP5 Model)

  • 박영기;최문술;이장춘
    • 대한환경공학회지
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    • 제22권4호
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    • pp.743-754
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    • 2000
  • WASP5 모형을 새만금호에 적용하여 모형의 매개변수 추정을 수행하였다. 추정방법으로는 수질항목 및 매개변수들을 몇 개의 군으로 나누어, 각 군의 매개변수들을 시행착오법에 의하여 순차적으로 추정하는 방법을 사용하였다. 모의 수질항목으로서 엽록소 a, 질소 순환요소들, 인순환요소들, BOD 및 DO 등을 포함하였으며, 복잡도 4에서 수질을 모의하였다. 새만금 담수호의 전체유역을 수 개의 물수지 단위 소유역으로 구분하여 물수지 분석을 하였다. 본 연구에서는 물수지 분석모형에 의한 1975년부터 1996년까지 22년간 월별 평균유입량을 산정하여 모형의 상류경계단에서의 유량 입력자료로 이용하였다. 1997 및 1998년의 수질측정자료는 계절별 평균치와 함께 계절별 매개변수의 보정 및 검증에 각각 사용하였다. 수질항목 및 관련 매개변수들을 계열별로 분류하여 추정하는 것이 많은 수의 매개변수 추정에 있어서 효율적인 방법임을 알 수 있었다. 모형의 보정 및 검증 결과, 유기물의 비점오염원에 대한 정량적 평가가 필요함을 알 수 있었다.

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사문암 지역 소나무림의 탄소수지 연구 (Carbon Budget of Pine Forest in Serpentine Area)

  • 양금철;남궁현민;김정섭;한미경;심재국
    • 한국환경생태학회지
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    • 제32권6호
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    • pp.676-685
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    • 2018
  • 경북 안동 사문암 지역의 소나무군락에서 2017년 01월부터 2017년 12월까지 1년간 매목조사, 미기상 및 토양호흡 측정을 통해 탄소수지를 측정하였다. 사문암 지역에서 토양호흡량은 연중 42.48 ~ 262.61 g $CO_2{\cdot}m^{-2}{\cdot}month^{-1}$의 범위로, 평균 $151.71{\pm}75.09g$ $CO_2{\cdot}m^{-2}{\cdot}month^{-1}$로 측정되었다. 대조구인 비사문암 지역의 소나무림에서는 연중 20.94 ~ 449.24 g $CO_2{\cdot}m^{-2}{\cdot}month^{-1}$의 범위로 조사되었으며, 평균 $165.09{\pm}118.96g$ $CO_2{\cdot}m^{-2}{\cdot}month^{-1}$로 측정되었다. 사문암 지역과 비사문암 지역의 총 탄소저장량은 각각 91.90, $222.85ton{\cdot}ha^{-1}$로 나타났으며, 연간 탄소흡수량은 각각 7.99, $17.41ton{\cdot}ha^{-1}{\cdot}yr^{-1}$로 나타났다. 사문암 지역은 연간 $5.3tonC{\cdot}ha^{-1}$, 비사문암 지역은 연간 $14.49tonC{\cdot}ha^{-1}$를 흡수하는 것으로 나타났다.

화학 응집제 투입에 따른 수질항목별 하수처리 반응곡선 (Saturation curves for chemical coagulation of wastewater treatment)

  • 류재나;오재일;이경종
    • 상하수도학회지
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    • 제24권5호
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    • pp.537-548
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    • 2010
  • Recently the Government has announced updated water quality standards for wastewater treatment effluent (become effective in 2012). That includes highly enforced regulations for T-P, BOD and COD, and a large budget, in particular for phosphorus removal, was set by the Ministry of environment. Chemical coagulation destabilizes colloidal particles so that particles grow to larger flocs, and solid particles are removed by solid-liquid separation. The efficiency of chemical coagulation depends on a various factors, including coagulant types and costs, construction and operation costs for the treatment facilities and so on. The proper selection should be based on the treatment efficiency of coagulants and underlying costs. The current research was to evaluate the treatment efficiencies of coagulants on a variety of wastewater influents and to develop saturation curves for several water quality parameters. Typical $Al_2(SO_4)_3$ and $FeCl_3$ were tested under a range of coagulant concentrations. The pollutant removal efficiencies of chemical treatment both for the $Al_2(SO_4)_3$ and $FeCl_3$ were especially high for T-P, followed by SS, BOD and COD. Correlation test also proved the highest relationship between SS and T-P.

Retrograde Well 형성을 위한 고에너지 이온주입에 대한 연구 (A Study on High Energy Ion Implantation for Retrograde Well Formation)

  • 윤상현;곽계달
    • 한국전기전자재료학회논문지
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    • 제11권5호
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    • pp.358-364
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    • 1998
  • Retrograde well is a new process for ULSI fabrication. High energy ion implantation has been used for retrograde well formation. In this paper the forming condition for retrograde well using high energy ion implantation is compared with that for conventional well. TW signals for retrograde p-,n-well($900^{\circ}C$),after annealing are similar trends to those of conventional ones($1150^{\circ}C$), however the signals for RTA have the highest value because of small thermal budget. Junction depths of retrograde well are varied from about 1.2 to $3.0\{mu}m$ as for conventional well. The peak concentrations of retrograde well, however, are about 10 times higher in values than those of conventional ones so that they can be used as any types of potential barriers or gettering sites. The critical dose for phosphorus implantation in our experiments is between $3\times10^{13} and 1\times10^{14}/cm^2$. Under the above critical dose, there are many secondary defects near projected range such as dislocation lines and dislocation loops.

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