Analysis on Material Flow Pertinent to Food Consumption in Urban Area: Comparison between Tokyo and Taipei

Abstract

This study first analyzed the development of waste and waste water treatment and disposal system in Tokyo and Taipei. Based on statistic data, Material Flow Analysis (MFA) and Substance Flow Analysis (SFA) were used for quantifying Nitrogen flow from food supply to emission to air, water and soil. First per capita per day protein supply from Food supply and utilization yearbook of Japan and Taiwan were used for calculation of per capita per day Nitrogen supply. Then MFA was used for calculating material flow of kitchen waste and human waste in waste and waste water treatment and disposal system. Next, emission from waste and waste water treatment and disposal system to air, water and soil was determined by statistic data and literature review. Finally, use the Nitrogen concentration in each material in the system, the Nitrogen flow was calculated. The result shows that the input of Nitrogen in Tokyo and Taipei gradually increased, and most Nitrogen were emitted as human waste into surface water. But with increase of incineration of waste and treatment of waste water, more and more Nitrogen were converted into gas, emitting into air. Waste compost and Kitchen waste as feeding stuff also help Taipei to recycle Nitrogen instead of emitting to surface water.