Waste Management Hybridization and Social Mechanisms: The Unpredictable Effects of a Socio-Technical Assemblage

Reducing total waste generation, increasing the rate of separate collection, and ensuring efficient material recovery are three key objectives recognized at the UN, EU, and national levels for achieving a sustainable waste management system. The policy and scientific debate has traditionally been polarized around two main collection systems: door-to-door and street collection, each with its own strengths and weaknesses. However, in recent years, hybrid waste collection models, which aim to integrate the advantages of both systems, have gained increasing attention. The impact of these models on sustainability, as well as the social mechanisms underlying their success or failure, remain underexplored. This paper analyzes a case study of a hybrid waste collection innovation implemented in eight small and medium-sized municipalities in Piedmont, Italy. The study has a twofold objective: (1) assessing the economic and environmental impacts of the system and (2) hypothesizing the social mechanisms that generate these effects. To address these research gaps, we develop a theoretical framework that combines the socio-technical system approach with analytical sociology. The framework is then operationalized through a quasi-experimental research design, which allows us to measure the effects of the hybrid innovation on a set of 17 indicators. The analysis is conducted by comparing the treated municipalities with a control group selected for its similarity. Empirical evidence reveals an unexpected and partially contradictory outcome: while the total amount of waste decreases, this reduction is not offset by a proportional increase in separate collection rates. Moreover, the quality of waste separation worsens. To explain this emerging pattern, we formulate a set of hypotheses—grounded in our theoretical framework—on the key factors influencing individual behavioral responses. Our provisional conclusion, which requires further qualitative validation, suggests that the interplay between economic incentives and social control in a context of imperfect awareness leads to ambiguous effects of hybridization in waste collection systems.