FY 2005 Dissemination Status of Johkasou, On-Site Treatment System of Domestic Effluent

The number of people served by the johkasou is 10.93 million, an increase of 310 thousand compared to FY 2004 (as of March 31, 2005). The dissemination rate of johkasou to total population is 8.6%, an increase of 0.2% compared to FY 2004 (8.4%).
Johkasou is an on-site treatment system of domestic effluent, including human wastes, which is installed at each household and discharges its treated water to the nearest public water area. Johkasou has the following features that make the system an effective measure for domestic effluent from houses which are dispersed.
(i) Duration of installation is very short and installation expense is comparatively low.
(ii) The system utilizes the natural purification capacity of small rivers and contributes to maintaining the water volume.
(iii) The system is easy to install, regardless of the geological formation.

Notes:
1. Dissemination rate is the ratio of population using johkasou to total population.
2. Population figures are rounded off to the nearest 10,000.

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