Scaling-up waste management solutions to mitigate plastic pollution in the Global South

Plastic pollution has become one of the major topics of our time, prompting an increase in research and innovation, and the negotiation of an international legally binding instrument to mitigate its harmful effects. Numerous resource recovery solutions have been proposed to reduce environmental emissions of plastics and support a circular economy. This thesis presents three published papers and one prepared for submission. The first paper explores risks to public safety and occupational health from recycled plastics, revealing shortcomings in the global plastic waste feedstock supply chain that allow chemicals of concern to transfer into new products, some posing human health risks. The second paper investigates resource recovery approaches to process waste plastics that have been proposed as solutions to plastic pollution and the circular economy. Processes involving high heat, pressure and combustion or those requiring sophisticated technological controls should be implemented cautiously in countries that lack sufficient monetary resources and technical expertise for safe management. Mechanical reprocessing emerges as one of the least harmful approaches due to its maturity and the lack of technical sophistication required for safe operation. In the third paper, I assessed the availability and quality of information on the prevalence and productivity of the informal waste sector (waste pickers); the main supplier to the resource recovery side. I found substantial methodological shortcomings, with much data being re-reported without verifiable provenance or based on subjective judgement. This led me to the fourth paper, in which I present a methodology for collecting data on the informal sector using a harmonised and scientifically robust approach. This method was field tested in Lalitpur Nepal in 2023. I propose that waste pickers are the logical custodians of material provenance and that they should be empowered to play an increasingly important role in supply chain quality assurance for waste plastics.