2019 Volume 75 Issue 2 Pages I_120-I_131
In a society with a declining population, the formulation of a location normalization plan has been underway in 400 cities nationwide from the standpoint of maintaining administrative efficiency and preventing disasters. In 154 cities of these cities, urban districts are being reduced and residential districts (hereinafter, “residential induction areas”) are being set up. This study focuses on sewage pipes that are considered to be an asset seriously affected by population decline among the already developed infrastructure assets in areas excluded from residential induction areas (hereinafter, "non-residential induction areas"). We verified, from the viewpoint of cost, whether alternative methods could be introduced into nonresidential induction areas instead of renewal by renovating sewage pipes, in cities where sewage pipes are already developed and residential induction areas are established.
As a result, we found that, by promoting residential induction based on the location normalization plan, alternative methods were sometimes advantageous in non-residential induction areas where population decline is expected. It was shown there is a need to consider certain elements upon reviewing prefectural concepts relating to sewage treatment systems which are already formulated and also formulating medium- to long-term stock management plans for sewage systems.
