| Budget Amount *help |
¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1992: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1991: ¥700,000 (Direct Cost: ¥700,000)
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| Research Abstract |
The contact aeration process with anaerobic filter tanks is frequently used in small-scale wastewater treatment plant in rural areas. In this study, the experiments were carried out in the actual and the model plants, and the Quantification analysis was also used in order to find the appropriate operating method for the nitrogen removal of this process. The results are as follows:
1)When large Metazoa such as asellus and physa have bred in large quantities on the contactors of aeration tanks, they have an unfavorable influence on the progress of nitrification.
2)Since the mass breeding of large Metazoa used to occur periodically from autumn to winter, it is important to prevent their mass breeding in autumn.
3)The back washing of the contactors can restrain their mass breeding to some extent, but the stopping of aeration of two days is needed to control them perfectly.
4)To advance the nitrification in the aeration tanks, operating attention should be paid to many factors, such as water temperature, DO concentration of aeration tank, BOD loading of aeration tank, returned water ratio, specific surface area of the contactors.
5)Discontinuation of aeration less than four hours in midnight of no inflow can save energy without deterioration of the treatment.
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