Integrated Waste-to-Energy Systems: A comprehensive review of Technologies, decision Frameworks, and sustainability metrics

Rising waste generation and growing energy demand have driven global interest in Waste-to-Energy (WtE) systems as a pathway toward sustainable waste management and resource recovery. However, existing WtE reviews remain fragmented: most are technology-centric, focusing on individual conversion routes, while others address environmental performance, economic feasibility, or decision-making methods in isolation, without linking them to waste characteristics or site-specific conditions. This limits the ability of researchers, policymakers, and stakeholders to systematically select suitable WtE solutions for specific regional contexts. This review addresses this gap by first characterizing major waste streams—municipal solid, industrial, agricultural and forestry, sewage sludge, medical, e-waste, and construction and demolition waste—and evaluating their compatibility with thermal (incineration, gasification, pyrolysis), biological (anaerobic digestion, landfill gas recovery), and emerging hybrid conversion technologies. It then examines site-specific factors governing WtE deployment, including economic conditions, geographic and logistical constraints, regulatory and policy drivers, and social acceptance. Building on these dimensions, the review proposes a novel conceptual 3D matrix framework integrating waste type, technology suitability, and site characteristics into a unified selection platform, and synthesizes multi-criteria decision analysis approaches supported by case study synthesis. Environmental and economic performance is further consolidated through life cycle assessment, levelized cost of energy, and circular economy indicators to establish a holistic sustainability assessment methodology. Finally, the review identifies key challenges in emission control, investment uncertainty, resource recovery, and public acceptance, and outlines future opportunities in AI-assisted optimization, carbon capture integration, and circular economy-driven WtE systems.