From Waste to Wealth: Exploring the Role of Biogas in Circular Economy Transitions Toward Zero-Waste Systems

Abstract

Decentralized biogas systems are increasingly viewed as part of circular bioeconomy transitions because they can link household energy provision to organic waste recovery, nutrient cycling, and resource efficiency. However, evidence remains limited on whether biogas adoption is associated with circular economy behaviors that extend beyond the technology's direct functions, particularly in rural low-income settings. This study examines the relationship between household biogas adoption and multidimensional circular economy practices, explicitly distinguishing household-level circularity from broader system-wide zero-waste transitions. The study used cross-sectional data from 360 rural households, comprising 178 biogas adopters and 182 non-adopters, and complemented these data with Key Informant Interviews (KIIs) and Focus Group Discussions (FGDs). An integrated theoretical framework draws on the Multi-Level Perspective, Diffusion of Innovation Theory, Institutional Theory, and the Theory of Planned Behavior to explain how socioeconomic, institutional, and behavioral conditions shape technology adoption and subsequent circular practices. A binary Logit model was used to examine determinants of biogas adoption. At the same time, OLS regressions and Propensity Score Matching (PSM) were employed to assess associations between adoption and multidimensional household circular economy outcomes. These outcomes included organic waste reuse, nutrient recycling, household waste-management behavior, reduction in virgin material consumption, product lifespan extension, and household-level material-flow closure. Biogas adoption was positively associated with organic waste reuse (β = 0.148, p < 0.001), nutrient recycling (β = 0.173, p < 0.001), and waste-management behavior (β = 0.129, p = 0.001). Positive associations were also observed for the extended circularity dimensions of virgin-material reduction, product-lifespan extension, and household-level material-flow closure. Education, income, livestock ownership, access to extension services, and environmental awareness were consistently linked to stronger circular practices. Qualitative evidence further indicated that manure recovery, digestate utilization, waste segregation, repair and reuse, and localized resource cycling were important behavioral pathways underlying these relationships. PSM results provided broadly consistent evidence after matching adopters and non-adopters. The findings suggest that household biogas adoption is linked to circular behaviors that extend beyond renewable-energy substitution, providing micro-level building blocks for circular bioeconomy development. However, these household-level associations should not be taken as evidence of a system-wide zero-waste transition or as causal effects. Broader circularity requires integration with extension systems, rural finance, cooperatives, waste-management infrastructure, agricultural value chains, and supportive policy institutions. The study contributes context-specific empirical evidence to the emerging literature on household circularity. It demonstrates how decentralized bioenergy can be examined within a broader socioeconomic and institutional pathway toward resource-efficient rural development.