Assessment of post-consumer plastic packaging waste flow in Chiang Mai: Challenges for low- and high-value plastic waste streams towards a circular economy

Recycling is crucial to achieving a sustainable plastic circular economy. Like many developing countries, Thailand can feasibly achieve source separation for recycling through both formal curbside collection and informal waste gatherers. While the government set specific recycling targets for plastic packaging waste (PPW) at 50% by 2022 and 100% by 2027, a comprehensive understanding of PPW composition and management remains limited. This study examined the flow of different PPW types across six product categories and seven resin types. The analysis covered the entire lifecycle from generation to end-of-life in Chiang Mai city. Measures were also recommended to improve circularity in PPW and reduce greenhouse gas emissions. Data collected in 2022 indicated that 23 ± 5% of the total PPW generated was recycled. Bottles had a higher recycling rate through informal channels, while multilayer packaging and cutlery ended up in landfills. Various resins were identified at source PPW generation, but buyers of recyclables currently accept a limited range of PPW categories, including high-value PET and HDPE bottles. Strictly promoting the recycling of high-value PPW will not, on its own, achieve a 50% recycling rate; the city also needs to address low-value PPW. The analysis highlighted challenges in current informal recycling channels and facilities in meeting the ambitious 100% recycling goal, highlighting the need for technological innovations, market development, policy tools, and strategies to support plastic circularity. Insights from this research could benefit other cities with similar waste management systems, particularly those in which informal financial channels drive recycling activities. • Examined post-consumer plastic packaging waste under the formal and informal sectors • Plastic packaging waste was analyzed into six product applications and seven polymers • PET and PE bottles were most accepted via the informal market-driven recycling route • Interventions for low-value plastic packaging waste are crucial to circularity