屎尿の好気性処理に関する研究
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概要
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At present night-soil disposal constitutes an important social problem. The purpose of this study was to determine whether "air supply in night-soil disposal", reported previously by Dr. Muto, might be of value in shortening the tims required for disposal and stabilizing the work. Materials used for experiments consist of samples brought over from Sewage Disposal Plant at Sunamachi, Tokyo, where night-soil removed from households are collected. The following results were obtained : 1. Air supply of 1.4 to 1.6 1/mim at 25℃ to 30℃ produced a supernatant fluid of low concentration and good quality in a short time after air supply had been cut. 2. The decrease of B. O. D. C. O. D., and ammonia concentration took place in less time when there was air supply than otherwise. Especially marked was the decrease of B. O. D. in the supernatant. 3. Whether there was air supply or not, numbers of coli bacteria and all other bacteria usually detected in night-soil showed a uniform manner of fluctuation. When there was air supply, the number of coli bacteria in the supernatant was markedly smaller. 4. Nitrifiers increased in number as air supply increased. Parallelism existed between the value of rH and the number of nitrifiers. It appears that rH may be an accurate index of oxygenation of night-soil. Denitrifiers increased in number as air supply was begun. It is considered likely that the action of denitrification comes into play only at the beginning of air supply. 5. The rate of embryonation of Ascaris eggs was higher when there was air supply than otherwise ; on the 20th day it was 95 % when there was air supply, and 87 % when there was not. 6. Measurement by Wargurg's manometer showed that oxygen intake of night-soil, removed from households by piecemeal, was 197.1cc. per 1 liter in 1 hour, which later rose and fell again to 21.3cc in 25 deys. The fact that the fall in oxygen intake was smaller when there was no supply of air seemed to indicate a larger percentage of C. O. D. in oxygen consumption.7. The supply of air suitable for the purpose seems to be 0.75 to 1.5 liter. If the amount were less than 0.5 liter, it would not be enough even to stir the content of the tank. 8. The optimal proportion of digested night-soil to be mixed with raw night-soil to achieve better result of digestion from practical viewpoint would be 50% 9. The temperature suitable for disposal of night-soil would be from 25℃ to 30℃ from physical and chemical point of view. When biological aspect of the problem, especially the effect of killing Ascaris eggs, is taken into consideration, it would seem that 37℃ is most economical and practical.
- 千葉大学の論文
- 1960-09-28