【Paper】
Distribution of Potential Biomass/Waste Resources and GHG Emission Analysis for Food waste Recycling Systems
Shin-ichi Sakai*, Yasuhiro Hirai*, Katsuhiko Yoshikawa** and Shingo Deguchi**
* National Institute for Environmental Studies
** Urban System Integration, Inc.
† Correspondence should be addressed to Yasuhiro Hirai:
National Institute for Environmental Studies
（16-2 Onogawa, Tsukuba, Ibaraki, 305-8506 Japan）

Abstract
In this study, we estimated the national potential of biomass/waste resources using statistics, and then analyzed the relationship between population size and potential mass in a community/person for each biomass item. It was found that for agricultural, forestal, and livestock biomass, the potential mass per person（kg/person/year）and accumulated mass for a certain population size（ton/year）were inversely proportional to the decrease in population size. On the other hand, for waste biomass（i.e. food waste, waste paper, sewage sludge），those quantities were directly proportional to the increase in population size.
We then conducted a case study of food waste treatment to compare GHG emissions（kg-CO2eq/ton-waste）for four different scenarios including the utilization of biogas with Fuel-Cell, for two model areas（rural/urban）．It was revealed that biogasification followed by the generation of electricity with biogas emitted less CO2 than when incineration and composting was performed for generation of electricity by FC, which has a greater effect on CO2 reduction in comparison to that of a gas engine. The difference in parameter settings between rural and urban areas causes a significant impact on GHG emissions, especially for incineration and composting.

Key words: biomass, potential mass, food waste, fuel cell, LCA