Area-wide use of reclaimed water in Tokyo, Japan

Abstract In Japan, wastewater treatment plants generate 1.09 x 10 10 m 3 of effluent in a year. 8.5 x 10 7 m 3 of it is reused. Several criteria have been proposed for reclaimed water quality. However there is not national standards yet. In this paper, reclaimed water use in Japan is briefly described. Existing quality criteria are also presented. In the context of reclaimed water use, Tokyo is one of the cities which have promoted the reuse of treated effluent. Especially, stream restoration project and area-wide water recycling projects are epoch-making projects. In this paper, area-wide water recycling project in Shinjuku district which is one of sub-centers in Tokyo is described. In this project, reclaimed water is used for toilet flushing in 19 high rise buildings. Construction cost, funding and user charges are also given.