Abstract
As a whole, Japan enters under a population decline, and the tendency is more remarkable in the local area than city area. If the work load and the consumption of supplies of public works are not reduced, the sustainability of the public services will be lost for the cost and environmental problems in such a area. The purpose of this study is to propose the sustainable system on the cooperation treatment of domestic waste water and combustible waste. Some measures were proposed, for example, the introduction of garbage disposer for the efficiency of the combustible waste collection and methane fermentation for combustible waste. Per person GHG emission and treatment cost were applied for evaluation indicators and calculated. As the results of examination for the area where a population decline was remarkable, the proposal systems can improve the efficiency compared with the present condition on the aspect of GHG emission and cannot improve on the aspect of treatment cost. The difference in the results was almost caused by labor cost and contract cost.
