• Title/Summary/Keyword: Variation of Discharge Ratio

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The Variation of the Dissolved Inorganic Nutrients in the Costal Area of Gunsan, Yellow Sea from 2001 to 2010 (서해 군산 연안의 2001년부터 2010년까지의 용존성무기영양염류의 변동)

  • Heo, Seung;Kweon, Jung-Ro;Park, Jong-Soo
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.17 no.4
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    • pp.357-365
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    • 2011
  • The variation of the dissolved inorganic nutrients were investigated four times per year in the costal area of Gunsan, Yellow Sea from 2001 to 2010. Water samples were collected at 10 stations and phsico-chemical parameters were analyzed including water temperature, salinity, suspended solids, dissolved oxygen, chemical oxygen demand, chlorophyll a and dissolved inorganic nutrients. The average of dissolved inorganic nitrogen(DIN) for ten years at Gunsan area showed similar concentration between surface and bottom. The average of DIN at surface was 0.421mg/L (0.198~0.846mg/L) and bottom was 0.344mg/L(0.148~0.717mg/L). The highest value of annual average of DIN at surface was 0.846mg/L in 2002 and the lowest value was 0.198mg/L in 2010. The percentage of ammonia, nitrite and nitrate for the average DIN of 10 years showed 27%, 3% and 70% which showed most of DIN was nitrate. Dissolved inorganic phosphate(DIP) for ten years at Gunsan area showed similar concentration between surface and bottom and DIP was decreasing from 2003 to 2010. The average of DIP of 10 years was 0.024mg/L and annual average 0.021mg/L in 2008, 0.007mg/L in 2009 and 0.008mg/L in 2010 which showed decreasing pattern from 2007 to 2010. The average of DIN/DIP ratio from 2002 to 2010 was 6.0(3.2~10.1) at surface and 4.6(2.6~7.0) at bottom. The average value of dissolved inorganic silicate from 2004 to 2010 showed 0.372mg/L at surface layer and 0.352mg/L at bottom layer and was on decreased from 2006 to 2010. The Spearman's correlation analysis was carried out to knowrelation among the salinity and dissolved inorganic nutrients at the surface and bottom layer. The correlation factor of DIN was -0.72, DIP was -0.46 and dissolved inorganic silicate was -0.63 at surface layer and DIN was -0.70, DIP was -0.44 and dissolved inorganic silicate was -0.57 at bottom layer. The dissolved inorganic nutrients at the nearshore of Gunsan was affected from the freshwater discharge of Geum river. Especially, a lot of DIN flowed into the nearshore of Gunsan from Guem river. The concentration of dissolved inorganic nutrients at Gunsan showed high at station 1, 2 and 3 and there was a little concentration differences according to the cruise time. The concentration of dissolved inorganic nutrients showed high value at the station 1, 2, 3 which exist nearshore of Gunsan city and it means these stations mainly affected by Geum river and Gunsan city. The annual average of dissolved inorganic nutrients showed gradually decreased from 2003 to 2010 and we need more research on this conditions.

An Economic Analysis of the Effluent Heat Supply from Thermal Power Plant to the Farm Facility House (화력발전소 온배수열 활용 시설하우스 열공급 모형 경제성분석 연구)

  • Um, Byung Hwan;Ahn, Cha Su
    • Korean Chemical Engineering Research
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    • v.56 no.1
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    • pp.6-13
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    • 2018
  • Utilizing the heat of cooling water discharge of coal-fired power plant, pipeline investment costs for businesses that supply heat to agricultural facilities near power plants increase in proportion to installation distance. On one hand, the distance from the power plant is a factor that brings difficulties to secure economic efficiency. On the other, if the installation distance is short, there is a problem of securing the heating demands, facility houses, which causes economical efficiency to suffer. In this study, the economic efficiency of 1km length of standard heat pipeline was evaluated. The sensitivity of the heat pipe to the new length variation was analyzed at the level of government subsidy, amount of heating demand and the incremental rate of pipeline with additional government subsidy. As a result of the analysis, it was estimated that NPV 131 million won and IRR 15.73%. The sensitivity analysis showed that NPV was negative when the length of heat pipe facility exceeded 2.6 km. If the government supports 50% of the initial investment, the efficiency is secured within the estimated length of 5.3 km, and if it supports 80%, the length increases within 11.4 km. If the heat demand is reduced to less than 62% at the new length of the standard heat pipe, it is expected economic efficiency is not obtained. If the ratio of government subsidies to initial investment increases, the elasticity of the new bloc will increase, and the fixed investment, which is the cost of capital investment for one unit of heating demand, will decrease. This would result in a reduction in the cost of production per unit, and it would be possible to supply heat at a cheaper price level to the facility farming. Government subsidies will result in the increased economic availability of hot plumbing facilities and additional efficiencies due to increased demand. The greater government subsidies to initial investment, the less farms cost due to the decrease in the price per unit. The results of the study are significant in terms of the economic evaluation of the effectiveness of the government subsidy for the thermal power plant heat utilization project. The implication can be applied to any related pilot to come.