| Project/Area Number |
18360237
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
水工水理学
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| Research Institution | Kobe University |
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Principal Investigator |
MICHIOKU Kohji Kobe University, Dept CivilEng, Professor (40127303)
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| Co-Investigator(Kenkyū-buntansha) |
YAJIMA Hiroshi Tottori Univ, Dept CivilEng, Associate Professor (10283970)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥9,490,000 (Direct Cost: ¥8,500,000、Indirect Cost: ¥990,000)
Fiscal Year 2007: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2006: ¥5,200,000 (Direct Cost: ¥5,200,000)
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| Keywords | Eutrophication / Organic compounds loads / Water purification / Lakes and reservoirs / aeration / Cost-benefit / Environmental loads / Optimization / 富栄義化 / 水工水理学 / 環境技術 / 水資源 |
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| Research Abstract |
In order to minimize the organic compound loads on a reservoir impoundment, performance of water purification systems including hypolimnetic aeration, selective withdrawal and vegetation in littoral zones were investigated by making field measurement and a numerical simulation of water quality. Focus was placed on behaviors of dissolved oxygen, nutrients and organic matters.
A water quality model was developed so that seasonal variation of water quality by considering various biochemical processes involved in the water quality balance. Model parameters were carefully determined so as to accurately reproduce the field data, where dissolved oxygen balance associated with hypolimnetic aeration was taken into consideration. The aeration system was a micro-bubble aerator unit that is able to generate fine bubbles with high solubility. In addition to the aeration, selective withdrawal operation was considered to regulate dissolved oxygen profile. Various types of system operation scenarios we
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re assumed with respect to aeration and selective withdrawal in order to maximize water purification performance. The basic idea for optimizing the system operation is to minimize total environmental loads not only on the water systems but also on the atmospheric environment as well as to maximize the cost-benefit. In the cost-benefit analysis, the initial cost necessary for the system construction and the running cost were taken into consideration. Parameters indicating the water purification performance, the cost and the total environmental loads were proposed so that an optimum strategy for the operation of the aeration system and the selective withdrawal devices was finally proposed.
On the other hand, an in-situ experiment on intermittent operation of the aeration system was carried out in order to find the best cost-performance operation by considering solubility and loss of the oxygen that is dependent on the seasonalvariation of thermal structure. The best operation of the intermittent aeration system was found through water quality measurement, which is able to minimize the energy consumption and emission of carbon dioxide.
As one of another ways of the water purification, nutrient intake performance of vegetation in littoral zone was investigated through a field survey in a natural lake.
The results from the present research program are to provide a new direction of dam reservoir management that is useful for environmental engineering use in the next years. Additionally, the total environmental loads on a river catchment can be minimized by applying the present research results. Less
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