2005 Fiscal Year Final Research Report Summary
Investigation Research of Effectiveness of Blue-green Algae Growth Control in Chinese Lakes as a Model Case
| Project/Area Number |
15254003
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Civil and environmental engineering
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| Research Institution | National Institute for Environmental Studies |
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Principal Investigator |
INAMORI Yuhei National Institute for Environmental Studies, Research Center for Material Cycles and Waste Management, Executive Researcher, 循環型社会形成推進・廃棄物研究センター, 室長 (10142093)
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| Co-Investigator(Kenkyū-buntansha) |
MIZUOCHI Motoyuki National Institute for Environmental Studies, Watershed Environments and Management Research Project, Senior Researcher, 流域圏環境管理研究プロジェクト, 主任研究員 (50260188)
XU Kaiqin National Institute for Environmental Studies, Watershed Environments and Management Research Project, Senior Researcher, 流域圏環境管理研究プロジェクト, 主任研究員 (20250722)
ITAYAMA Tomoaki National Institute for Environmental Studies, Research Center for Material Cycles and Waste Management, Researcher, 循環型社会形成推進, 廃棄物研究センター・研究員 (80353530)
IWAMI Noriko Meisei University, Science and Engineering, Associate Professor, 理工学部, 助教授 (00353532)
MATSUMURA Masatoshi University of Tsukuba, Institute of Applied Biochemistry, Professor, 応用生物化学系, 教授 (50015781)
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| Project Period (FY) |
2003 – 2005
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| Keywords | Asian countries / Eutrophic lake / Bio-Eco Engineering / Effect in preventing growth of blue-green algae / Unpowered anaerobic filter bed / Soil-trench treatment facilit / Cylindrical intermittent aeration water pumps / Toxic blue-green algae |
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| Research Abstract |
We obtained the following empirical results for consideration in formulating measures to reduce the load on the aquatic environment in the target lakes of Guizhou Province of China as a case study. It is possible to reduce concentrations of nitrogen and phosphate in treated domestic wastewater to less than 20mg・1^<-1> and less than 1mg・1^<-1>, respectively, in a stable manner by optimizing management and maintenance, which includes eliminating waste sludge from advanced Johkasou systems. It is possible to reduce concentrations of nitrogen and phosphate to less than 10mg・1^<-1> and less than 0.5mg・1^<-1>, respectively, through optimal operation of the unpowered anaerobic filter beds of soil-trench domestic wastewater-treatment facilities (30m^3・d^<-1>, while pursuing energy conservation. It is possible to reduce by 60 percent of the concentration of chlorophyll-a at dam sites by controlling algal growth through the operation of cylindrical intermittent aeration pumps. To reduce existing concentrations of toxic blue-green algae it is possible to keep the population density of Ceriodaphnia dubia, a predator that is present during, filtration, at a high level by increasing the level of aquatic vegetation. With a view to introducing Bio-Eco Engineering, we also conducted a survey of the current situations in the lakes of neighboring countries. We found that the existing amounts of blue-green algae in these lakes have reached 150,000cells・ml^<-1>, and that problems with water utilization are growing obvious because of the increasing amounts of toxic blue-green algae, as in the eutrophic lakes in China. We clarified the fact that eliminating nitrogen and phosphate through the application of Bio-Eco Engineering, which works well to prevent the growth of toxic blue-green algae, is very important to control eutrophication in these aquatic environments. The methods described above are expected to be very useful.
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