Advanced composting simulation technologies: A systematic review of methodological frameworks and applications

The conventional composting systems face technical limitations due to the complex substrates and nonlinear biochemical dynamics, resulting in unstable efficiency. The integration of computational approaches has advanced process simulation capabilities, creating novel opportunities for system optimization and performance enhancement. This study provides a comprehensive critical analysis of simulation methodologies applied to composting systems, with a focus on reaction kinetic modeling, multiphase computational fluid dynamics (CFD) simulations, and machine learning approaches. Unlike conventional reviews that adopt a singular perspective, this work not only examines the theoretical foundations and distinct advantages of each method, such as the mechanistic interpretability of mathematical models, the multi-physical field representation capability of CFD, and the data-driven modeling strengths of machine learning, but also clarifies the positioning and boundaries of each approach in terms of modeling logic, applicability, and interdisciplinary integration. Advancing these simulation technologies holds significant promise not only for process optimization but also for enhancing the environmental sustainability and resource efficiency of organic waste management, thereby contributing to broader circular economy objectives. Finally, we propose several promising research directions, including multi-physics coupled modeling that integrates biochemical and transport interactions, digital twin architectures enabling cyber-physical system integration, and a carbon emission accounting system aligned with carbon neutrality goals. This review will provide theoretical foundations for precision control in industrial-scale composting operations, bridging the gap between computational simulation and practical engineering implementation, thereby fostering the intelligent evolution of organic waste treatment.