Managing PET Plastic Waste in Samarinda, East Kalimantan: Public Awareness, Infrastructure Gaps, and Pretreatment Strategies for Biodegradation

Polyethylene terephthalate (PET) is a widely used packaging polymer that persists for decades, contributing to plastic pollution and urban environmental sanitation challenges. In East Kalimantan, municipal solid waste generation reaches 808,811.50 t/year, with Samarinda contributing 220,209.83 t/year, of which 12.94% (~28,495 t) is plastic. This study assessed PET waste management in Samarinda by integrating waste generation and infrastructure analysis, a community-based survey of knowledge and practices, and laboratory-scale evaluation of PET pretreatment methods as a preliminary step to support subsequent biodegradability. A mixed-methods approach was applied, combining a cross-sectional questionnaire survey, desk review of waste-management infrastructure, and experimental pretreatment of post-consumer environmental PET waste collected from rivers and a final disposal site. Pretreatments included UV exposure, oven heating, and sunlight exposure applied to PET sheets and flakes. Mass-loss differences were analyzed using one-way ANOVA, while FTIR and SEM were used to characterize PET functional groups and surface morphology. Results showed moderate knowledge of PET environmental impacts but low exposure to education (10.70%), limited household sorting (20.90%), and minimal recycling participation (7.70%). Multivariate analysis showed no statistically significant association between sociodemographic or knowledge-related variables and PET recycling frequency or controlled disposal behavior (p > 0.05), suggesting a knowledge–practice gap. Experimentally, particle size significantly influenced mass loss (p < 0.05), with PET flakes showing higher mass loss than PET sheets. These findings indicate that PET waste management requires integrated strategies combining infrastructure strengthening, targeted education, consistent 3R implementation, and pretreatment-assisted approaches to support future PET biodegradation studies.