2023 Volume 46 Issue 2 Pages 35-45
The ratio of electricity consumption in sewage treatment to the total electricity consumption in Japan is increasing yearly. Thus, it is important to efficiently operate sewage treatment plants considering the quality of incoming sewage. However, no study has identified how the overall quality of sewage water in urban areas relationships to its sewershed characteristics. Therefore, in this study, we analyzed data from the Tokyo metropolitan area to understand the relationship between the spatiotemporal distribution of sewershed characteristics and sewage water quality. Results indicate that biochemical oxygen demand and total nitrogen concentration are correlated to daytime population density in each sewershed, which is affected by land use. In addition, sewage water quality showed seasonal relationships to utility expenditures and monthly air temperature, indicating the temporal relationship between these sewershed characteristics and sewage water quality. In conclusion, through this study, the spatiotemporal distribution of sewershed characteristics was clarified and the relationship was identified between sewershed characteristics and sewage water quality. Results imply that the sewage water quality in the Tokyo metropolitan area can possibly be modeled on the basis of daytime population density, land use, utility expenditures and monthly air temperature, which might be beneficial for the efficient long-term operation of sewage treatment plants.
