| Project/Area Number |
12450211
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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 |
Civil and environmental engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
MINO Takashi The University of Tokyo, Graduate School of Frontier Sciences, Professor, 大学院・新領域創成科学研究科, 教授 (60166098)
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| Co-Investigator(Kenkyū-buntansha) |
KURISU Futoshi The University of Tokyo, Graduate School of Engineering, Research Associate, 大学院・工学系研究科, 助手 (30312979)
SATOH Hiroyasu The University of Tokyo, Graduate School of Frontier Sciences, Associate Professor, 大学院・新領域創成科学, 助教授 (90251347)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2001: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Keywords | activated sludge process / excess sludge / ozone treatment / zero emission / inorganic compounds / sludge solubilization / metal salts / ICP analysis / 微生物群集解析 / DGGE |
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| Research Abstract |
In order to reduce the environmental impact from wastewater treatment processes and to achieve "zero emission" technology, it is very important to have wastewater treatment systems that can maximize mineralization of organic mattes in the wastewater and to minimize the excess sludge production. For such a purpose, the activated sludge process with a sludge digestion stream has been developed, in which a part of the return sludge is digested and solubilized before returning to the aeration tank. This is a promising process, but it is necessary for the purpose of practical use of the system to solve the problem of the accumulation of inorganic components in the system and to confirm the long-term stability of the system. In the present study, an activated sludge process with a return sludge digestion by ozonation was operated in the laboratory with a municipal wastewater and the material, balance of different inorganic compounds was investigated. The specific objective of the study was to monitor the behavior of inorganic matters entering the system by using ICP analysis and to clarify the mechanism of their behaviors. The experimental results indicated that: 1) Some metals like Na did not accumulate in the system and go out in the effluent in the soluble form. 2) Some metals like Fe and Al accumulated in the sludge, but after some time the accumulation appeared to come to a saturation, and 3) Some metals like Zn and Cu continued to accumulate in the sludge throughout the experimental period. Among these metals, Fe showed an interesting behavior: after the accumulation of Fe came to saturation, the effluent soluble Fe concentration increased, indicating there is a mechanism of Fe re-solubilizatlon. It is needed to further investigate the chemical mechanism of this re solubilization of Fe.
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