Circular economy systems analysis of high-density polyethylene (HDPE) plastic packaging by informal recycling in Brazil, Global South: Quality assurance, rejects and value appropriation

Plastic pollution remains a major environmental challenge in the Global South, particularly due to the limited unsderstanding of how informal and formal recycling stakeholders interact along complex value chains. High-density polyethylene (HDPE), widely used in consumer packaging, is often overlooked in systemic recycling assessments. In this study, we investigate the systemic complexities of a polymer recycling chain insufficiently investigated, focusing on high-density polyethylene (HDPE) – a core contributor to plastics pollution in the Global South, via mismanaged waste. Rigid blow-moulded HDPE is widely used in fast-moving consumer goods containers; it is also sought-after for the production of ‘secondary’, recycled HDPE (r-HDPE). Starting from a single location (Brazilian town) and a waste picker cooperative (informal recyclers – IRS), we investigate the collection/sorting of municipal solid waste (MSW) recyclables along the downstream value chain of scrap dealing, reprocessing, and manufacturing. The methodological frameworks of technical networks, material flow analysis (MFA), and complex value optimization for resource recovery were used. Results demonstrate an informal to formal spectrum of operations, with clear transition points. The material quality standards required at manufacturing with r-HDPE are poorly applied at the collection stage, indicating a problematic quality management interfacing. Material rejects (losses), allowable contamination level, and monetised value of recyclate are interlinked at each stage. The most substantial value creation and appropriation is accomplished at the initial collection/sorting waste picker stage, followed by the value creation at the final production of the r-HDPE pellet. Reprocessors bear disproportionate material losses, counterbalanced by purchasing pricing. Despite overall rejects of 29 % wt. (ar) , a high actual recycling rate for rigid HDPE is achieved: 38 % wt. (ar) , indicative of an effective collection for recycling and refined manual sorting by the partially formalized IRS. These novel insights on informal recycling networks can inform effective interventions to expand circularity and prevent plastic pollution. • HDPE recycling chain mapped from informality to formality in Brazil. • Rejects ∼29 wt% link directly to value creation and pricing along the chain. • rHDPE quality standards poorly shared with informal chain stages. • Brazilian case achieves high recycling rate of ∼38 wt% for rigid HDPE despite low-tech. • Global South baseline informs policy for inclusive circular plastics systems.