1996 Fiscal Year Final Research Report Summary
Simultaneous nitrification and denitrification treatment using a bio-electro reactor
| Project/Area Number |
07650635
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | GUNMA UNIVERSITY |
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Principal Investigator |
KURODA Masao Gunma University, Faculty of Eng., Professor, 工学部, 教授 (40008446)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Tomohide Gunma University, Faculty of Eng., Research Associate, 工学部, 助手 (60251120)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Advanced treatment / Nitrification / Denitrification / Bio-electro reaction system / Nitrifying bacteria / Denitrifying bacteria / Electrolysis / Hydrogen |
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| Research Abstract |
Feasibility of a novel simultaneous nitrification and denitrification treatment using a bio-electro reactor to which was applied biological and electrochemical reactions was investigated. The following results were obtained in this study.
1.Nitrification proceeded by nitrifying bacteria immobilized on the anode when electric current was applied to the electrodes in ammonia-nitrogen contained water. The nitrification rate promoted with an increase in the applied electric current, but decreased under the condition of current density over 0.15 mA/cm^2. Therefore, there may be the optimum operational condition of current density.
2.Nitification and denitrification proceeded simultaneously by using a bio-electro reactor which consisted of the carbon electrodes immobilized nitrifying bacteria and denitrifying bacteria as anode and cathode, respectively, when an electric current was applied. The nitrification and denitrification occurred by utilizing oxygen and hydrogen produced by eletrolysis of water, respectively and promoted with an increase in the applied electric current. However, these efficiencies decreased under the condition over a certain value of the applied electric current.
3.DO concentration in the bulk liquid influenced both nitrification and denitrification rates. The high-DO concentration in the bulk liquid led to high nitrification and low denitrification efficiencies in the bio-electro reactor. However, nitrification was promoted and denitrification occurred in the cathodic biofilm by the applied electric current even at high DO concentration in the bulk liquid.
4.Performance of the bio-electro reaction method for the treatment of the municipal wastewater was investigated by setting the electrodes immobilized nitrifying bacteria and denitrifying bacteria into an aerated biofilter reactor. Nitrification and denitrification efficiency increased by the applied electric current and the degradation of BOD constituents was also enhanced.
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