Impact of municipal waste and waste water management change on nutrients flow to surface water and ground water in Asian mega-cities

In this research, long-term nutrient (Nitrogen) flow of Tokyo, Beijing (1960-2004), and Taipei (1970-2004) was analyzed. Substance Flow Analysis were used for quantifying nutrient flow from food supply to household consumption, then discharged as waste or waste water to treatment and disposal system, after treatment emit into environment as emission to water, air and soil. In urban area, the nutrient mostly emitted as human waste, which was traditionally considered as fertilizer in Asian cities, but with increase concern on health problem and using of chemical fertilizer, reuse human waste as fertilizer decreased. Scenario shows great potential of recover Nitrogen from human waste which was traditionally treated as fertilizer before prevailing use of chemical fertilizer. Recover of Nitrogen could not only reduce emission to environment but also reduce the use of chemical fertilizer.