Waste Input-Output Material Flow Analysis Model

—Newly Developed Top-down MFA Approach—

Abstract

Materials flow analysis (MFA) is a method useful in accounting for the supply and demand structure of resources and wastes, as well as the international material balance. There are two classifications within the MFA approach : the bottom-up approach and the top-down approach. The top-down approach uses statistics data, such as input-output tables, while the bottom-up approach uses unit numbers for specific products and their composition. There is a weakness in the application of input-output analysis to MFA because it does not properly take into consideration the mass balance condition between inputs and outputs (physical inputs=physical outputs+process waste+emission) in the production of goods. To cope with this, a new hybrid approach to MFA has been developed, the WIO-MFA (Waste Input-Output Material Flow Analysis) Model (Nakamura and Nakajima, Materials Trans. 2005). This paper introduces the WIO-MFA model and its application to a detailed MFA for polyvinyl chloride (PVC).