(624b) Identifying Strategies for Systems Scale Transition to Circular Economy Via Physical Supply Use Tables Developed from Bottom-up Models: A Case Study on Illinois Agro Economy

Bio-based production provides versatile opportunity for transition to circular economy because of ample availability of agricultural and animal waste in a region, which still needs attention for proper management. However, understanding agricultural material flows in production system is crucial to achieve circular economy to identify the opportunities for feedstock substitution and auxiliary use. By substituting the waste products as feedstock inputs, the primary sectors of the economy can be more circularized with very low waste flows going to the environment. Hence, it is crucial to identify all possible sources and quantity of agriculture wastes that can be used as a feedstock which can be achieved by a comprehensive material flow accounting for the target economy.

In this work, we propose using computationally developed physical supply use tables (PSUTs) to perform an economy wide material flow analysis to identify and account agricultural wastes that can be used as substitution to existing feedstock, thus providing opportunity for redesign of material flows in economy towards higher circularity. These PSUTs are based on mechanistic engineering models that were developed using fundamental mass and energy balance equations. Using the PSUTs, we identify the potential substitution of feedstock and redesign the system with proposed substitution. Further, with our approach we study the overall impact of this transition in terms of material use efficiency, nitrogen use efficiency and energy efficiency of the system. The case study will demonstrate the potential of this approach to study other questions pertaining to sustainable redesign of material flows towards higher circularity.