Municipal solid waste management in Europe has undergone a profound transformation over the past three decades, driven by regulatory harmonization at the European Union level, technological advances in waste treatment, and evolving societal expectations regarding sustainability and climate responsibility. Central to this transformation is the separate collection of waste fractions, particularly bio-waste and dry recyclables, which is widely regarded as a prerequisite for high-quality recycling and material recovery. This article develops a comprehensive and integrative analysis of the determinants, impacts, and policy implications of separate collection systems in European municipalities, with a particular emphasis on behavioral responses, institutional arrangements, and governance models. Drawing strictly on the provided body of literature, the study synthesizes insights from environmental economics, public administration, and waste management engineering to explore how collection design, pricing instruments, privatization, inter-municipal cooperation, and regulatory frameworks interact to shape recycling outcomes. The article further examines how door-to-door bio-waste collection can generate positive spillovers for the collection of dry recyclables, how unit-based pricing affects household behavior, and how heterogeneous treatment effects challenge conventional evaluation methods in policy analysis. Rather than offering a narrow empirical assessment, the paper adopts a theoretically rich and descriptive approach, unpacking causal mechanisms, contextual contingencies, and long-term system dynamics. The findings highlight that separate collection performance cannot be understood in isolation but emerges from a complex interplay of behavioral incentives, institutional capacity, market structures, and legal constraints. The discussion critically assesses limitations in current approaches and identifies future research directions, particularly regarding equity, administrative feasibility, and the alignment of climate and resource efficiency objectives. The article concludes that achieving high recycling rates in Europe requires not only technical optimization but also coherent policy mixes and adaptive governance frameworks capable of accommodating local diversity while meeting overarching European targets.