Study on Reduction of Mixed Water Salinity by Sound Wave —Toward Water Scarcity Issue-Solving in Isolated Islands in the World

There are so many Isolated Islands (inhabited islands) in the world, including Japan. However, at present islanders, there have been faced with the decline of industries, serious concerns of rapid aging and very low birthrate without children and water scarcity issues etc. It can be said that these situations are under the environment which shows a microcosm of Japanese and/or world survival society in the near future. In this paper, the experimental data on the reduction of the mixed water (seawater & rainwater) salinity by the sound wave when changing the volume ratio were first shown, taking into the characteristics of the Isolated Islands. Next, the main analysis result on the water qualities of mixed water with which sound wave was irradiated was shown and the consideration mainly based on the WHO drinking water quality standards was carried out. Finally, through a simple water quality improvement apparatus using small hydroelectric power, a consideration regarding a possibility of the purification of the water (to be a drinking water) based on the solar circulation energy (regenerative type’s natural energy) such as small hydropower utilization, natural sunlight utilization, natural gravity utilization, natural oscillation utilization has been described in the paper.