In response to challenges within the solid waste industry, this research focused on enhancing Material Recovery Facility (MRF) operations using Lean Six Sigma. Employing the DMAIC framework, the study tackled recurring downtime at a Guaynabo, Puerto Rico MRF. Key findings include identifying root causes, such as conveyor jams and material entanglements, and proposing improvements like ongoing training, proactive maintenance, and specialized equipment like the Industrial Bag Opener and Motorized Brush. The study projected a 30% downtime reduction, yielding an annual saving of around $97,630. This ROI calculation factored in operational enhancements and equipment costs, highlighting the financial benefits of Lean Six Sigma integration. Emphasizing Lean Six Sigma's value in MRF operations, the study provides insights for the industry and underscores data-driven waste management enhancements. Moreover, its alignment with UN Sustainable Development Goals 8, 9, and 11 highlights contributions to decent work and economic growth (SDG 8), industry, innovation, and infrastructure (SDG 9), and sustainable cities and communities (SDG 11). The research showcases the practical advantages of Lean Six Sigma in MRF operations, serving as a model for the wider waste management sector and affirming the value of data-driven enhancements.