Unlocking circular economy potential in pig farming: Waste, impacts and pathways from Southeast Vietnam

Pig farming is a cornerstone of food security and rural livelihoods in Vietnam, but rapid intensification, particularly in the Southeast hub, has triggered severe environmental degradation through substantial waste generation and greenhouse gas emissions. While biogas systems are widely adopted, inefficiencies in waste management continue to threaten water and air quality. This study provides a novel, interdisciplinary evaluation linking quantified environmental burdens to farmers’ socioeconomic readiness for a circular economy transition in developing economies. Unlike previous research, it identifies specific behavioural and institutional barriers to resource recovery. A mixed-methods approach was applied, integrating a literature review, field surveys and semi-structured interviews across 18 representative pig farms in four provinces. Greenhouse gas (GHG) emissions were estimated based on IPCC Tier 2 guidelines and a SWOT analysis was conducted to determine the feasibility of a circular waste linkage model. Results reveal substantial waste outputs, with each farm averaging 133.31 m³/day of wastewater and 6.57 tons/day of manure, generating 236.48 tons CO 2e /day in GHG emissions - 93% of which is methane. Despite high biogas adoption, 44.4% of farms fail national effluent standards and composting is nearly absent, revealing significant institutional and implementation gaps. Key barriers include high infrastructure costs and limited technical expertise. However, 94.4% of farmers expressed high willingness to join circular models, motivated by potential cost reductions and improved social acceptance. These findings interpret the current waste crisis as a policy opportunity, integrating economic incentives with regional circular hubs could reduce methane emissions, fostering a more sustainable and resilient livestock industry.