The metabolic closure: A life cycle theory of waste valorization and the circular economy transition

This study argues that the key to metabolic closure in the circular economy, and hence to overcoming the systemic inertia that sustains linear systems, is a life-cycle theory of waste valorization. This study goes beyond aspirations and uses an integrated conceptual framework that combines circular economy concepts, the 10R hierarchy, and life cycle assessment (LCA) methodology. Actual data from hybrid LCA and Agent-Based Modeling research support this. The results demonstrate that efficient valorization is not an intrinsic property but requires a thorough, system-level life-cycle study to avoid premature or ecologically damaging loop closure. Consequently, a new 10R-LCA framework is proposed as an operational architecture to prioritize valorization routes from repair to recycling and beyond, which can be validated to deliver synergistic environmental, economic, and social benefits. Its key contribution is a rigorous and practical decision-making model. It redefines “metabolic closure” as a systemic conclusion attainable only through life-cycle-optimized valorization, as evidenced by substantial savings in emissions and costs through the coordinated integration of materials. A crucial move from advocacy to a practical, data-driven approach is vital for a real linear-to-circular change in the industry. Keywords: Circular Economy, Waste Valorization, Life Cycle Assessment (LCA), 10R Framework, Metabolic Closure, System Optimization, Sustainable Materials Management.