Water recycling systems in Tokyo

Abstract

Water resources for water supply of Tokyo depend mainly on surface water from many dams and rivers in the Kanto province and ground water in a part of Tokyo. But because of an increase in water demand and a reduction in water resource development, a water shortage has occurred every few years. The Tokyo Metropolitan Government (TMG) announced a new policy to conserve limited water resources and has implemented several measures to promote the consumers' consciousness for water conservation, use of reclaimed water and development of water-saving appliances. With water for miscellaneous use (=nonpotable use), the TMG has encouraged “reuse of treated wastewater”, “use of industrial water for miscellaneous use”, and “use of rainwater”. According to three types of reclaimed water systems - individual building, limited area, and broad area recycling systems - the TMG established a guideline for the water for miscellaneous use. This paper describes the background of the issue, contents of the guideline, and results of the promotion and theme in the future.