戦前期大阪市における屎尿処理市営化

―下水処理構想の挫折と農村還元処分の拡大―

抄録

After 1910, urbanization and increased use of other fertilizers resulted in the loss of the value of human waste as compost. The night soil recycling networks of Osaka, formed in the early modern period, collapsed and the city was forced to provide human waste dis-posal as a municipal service.
Previous studies on the transition to this municipal service have shown that improve-ments in hygiene conditions in Japan came later than in Western countries because Japa-nese cities depended on systems of human waste recycling networked with suburban farming villages.
However, Takeshi Nagashima compared statistical data of Osaka with that of Tokyo and raised questions about the effect of Osaka’s modern sewage disposal system. According to this study, Osaka’s typhoid morbidity rate in the 1930s was higher than that of Tokyo, which placed an emphasis on the night soil recycling system. In short, the sewage disposal system built in Osaka did not provide a fundamental solution, and problems of infectious disease persisted for a long time. Regarding reasons for this, Nagashima pointed out the city’s financial limitations but did not examine the more concrete problems Osaka faced when creating its sewage disposal system.
Thus, this paper focuses on Osaka’s night soil disposal plan and examines obstacles encountered when building a modern sewage disposal system as well as factors that pro-longed the city’s continued sanitation problems.
After human waste disposal became stagnant in the city center, the government revised the Filth Cleaning Law on May 17, 1930. The revised law included human waste as part of cities’ waste disposal obligations. After this revision, Osaka considered the construction of a sewage disposal system to be a more important municipal measure than its human waste removal service. However, despite the city’s plan, Osaka’s residents were opposed to such a measure because they were reluctant to spend much money on flush toilet installation. Therefore, the measure was ineffective in solving the city’s waste disposal problems.
In the end, Osaka was entrusted with the final disposal of human waste. Because the measure preserved the livelihoods of night soil peddlers and reduced the city’s waste dis-posal cost, the city cooperated with Osaka Prefecture and agricultural associations to build human waste storage tanks, thereby intervening in the process of human waste disposal. As a result, the city of Osaka supplied human waste to many surrounding farming villages in the prefecture, simultaneously relieving its human waste problems.