| Project/Area Number |
11480151
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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 |
環境保全
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| Research Institution | Oita University |
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Principal Investigator |
HANO Tadashi Faculty of Engineering, Oita University Professor, 工学部, 教授 (80038067)
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| Co-Investigator(Kenkyū-buntansha) |
TAKANASHI Hirokazu Faculty of Engineering, Oita University Research Associate, 工学部, 助手 (40274740)
HIRATA Makoto Faculty of Engineering, Oita University Associate Professor, 工学部, 助教授 (20264327)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 2000: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1999: ¥4,300,000 (Direct Cost: ¥4,300,000)
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| Keywords | Developing Countries / Simplification / Denitrification / Autotrophic Bacteria / Sulfur / Thiobacuius denitrificans |
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| Research Abstract |
A simple denitrification process suitable for developing countries was proposed by employing autotrophic Thiobacillus dentrificans. The effect of nitrate concentration, phosphorus concentration, alkalinity and inhibitants on the rate of denitrification was investigated with a column packed with sulfur and limestone particles involving denitrification bactaeria, and the following results were obtained.
1) The denitrification proceeded without substrate inhibition up to 1,000 g-nitrate-N/m^3, which demonstrated that most of the wastewater cold be treated without dilution.
2) The minimum phosphorus concentration was evaluated under constant pH controlled by borate-buffer showing that 1 mg-P/m^3 was enough for the present process. However, higher phosphorus concentration was necessary when borate buffer was not used. This was because pH at the reaction site, probably the boundary between biofilm and surface of sulfur particles, may drop due to the release of proton as a result of denitrification.
3) The minimum alkalinity was found as 600g-CaCO_3/m^3 for load of 420g-N/(m^3/d). The inhibition with fluoride and Ni was not observed until 90 and 3 g/m^3, respectively.
It was concluded that the present system was suitable for developing countries because it was simple without any special instruments or technical care and it offered stable performance with slight request for phosphorus even in concentrated wastewater.
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