1986 Fiscal Year Final Research Report Summary
Experimental Study on the Improvement of Rural Community Sewage Treatment Facilities --- Denitrification by Intermittent Aeration ---
| Project/Area Number |
59860023
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
農業土木
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| Research Institution | Kyoto University |
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Principal Investigator |
NISHIGUCHI TAKESHI Professor, Faculty of Agriculture, Kyoto University, 農学部, 教授 (20026454)
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| Co-Investigator(Kenkyū-buntansha) |
KANEKI RYOICHI Associate Prof.,Faculty of Agriculture, Shiga Prefectural Junior College, 農学部, 助教授 (30074082)
YOSHIDA ISAO Associate Prof.,Faculty of Agriculture, Tottori University, 農学部, 助教授 (40038237)
TAKAHASHI TSUYOSHI Associate Prof.,Faculty of Agriculture, Kyoto University, 農学部, 助教授 (80021707)
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| Project Period (FY) |
1984 – 1986
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| Keywords | Rural community sewage treatment / Intermittent aeration / Denitrification / Load changing / 自動制御 |
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| Research Abstract |
In this study, labolatory and field experiments were carried out in order to establish the nitrogen removal techniques of intermittent aeration and its operational method, for the development of new sewage treatment method, which was adaptable to the small-scale sewage treatment facilities such as those of rural community.
In the actual sewage treatment facilities in small-scale, sewage inflow had great fluctuations for one day cycle, namely two peaks of 6-9 a.m. and 6-10 p.m. were observed with the pollution concentration. Therefore, the pollution load of sewage could be characterized by the great hourly changes in small-scale treatment facilities.
The results of laboratory experiment of activated sludge method with intermittent aeration showed that the treatment was able to cope with such a great changes in load, showing the nitrogen removal rate higher than 70%, when the concentration of MLSS was kept at rather high between 5000 and 5500 mg/L, even when the condition of low water temperature at 8゜C.
Since in winter season the activity of activated sludge was lowered because of low water temperature, high rate removal of nitrogen could be maintained when the concentration of MLSS was kept at rather high and the total aeration time was reduced according to the changes of DO. Field experiments using the actual sewage treatment facility showed the same results as those in laboratory.
Finally self-control system of intermittent aeration treatment was proposed in which the individual aeration time and the removal of excess sludge were controlled by means of the measurement of sedimentation of sludge surface using the optical sensor.
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