Safely recovering value from plastic waste in the 8 Global South : Opportunities and challenges for 9 circular economy and plastic pollution mitigation 10 11

22 Over the coming decades, a large additional mass of plastic waste will become available for 23 recycling, as the world’s largest fast moving consumer goods companies step up efforts to 24 reduce plastic pollution and facilitate a circular economy. Finding ways to recover value from 25 this material is a substantial challenge that has prompted exploration of novel processes, such as 26 ‘chemical recycling’, as well as more established ones, such as incineration with energy 27 recovery. Many of these efforts will take place in the Global South, where plastic pollution and 28 due to mismanagement of waste are most acute. New infrastructure will need to be developed, 29 and it is important that the processes and systems chosen do not result in adverse effects on 30 human health and the environment. This concern is particularly acute in countries that lack 31 effective, well-resourced and independent systems for environmental regulation and the 32 protection of occupational and public health. Here, we present a rapid review and critical semi33 quantitative assessment of the potential risks posed by eight approaches to recovering value 34 (resource recovery, circular economy) from post-consumer plastic packaging waste that has 35 been collected and separated with the purported intention of recycling. The focus is on the 36 Global South, where there are more chances that high risk processes could be run below 37 standards of safe operation (though much of the evidence reviewed is inevitably based on 38 research outcomes obtained in the Global North context). Our assessment indicates that under 39 realistic, i.e. non-idealised operational conditions, mechanical reprocessing is the least impactful 40 on the environment and is the most appropriate and effective method for implementation in the 41 Global South. We find little difference in potential risks between so called ‘bottle-to-fibre’ and 42 ‘bottle-to-bottle’ processes as they involve similar processing and both result in substantial 43 avoided burdens from virgin production. The lack of real-world process data for the groups of 44 processes known as ‘chemical recycling’ make them hard to assess. At present, there is no 45 strong evidence that any of them have reached commercial stability when applied to processing 46 post-consumer plastic packaging waste. Given this lack of maturity and potential for risk to 47 human health and the environment (inferred through the handling of potentially hazardous 48 substances under pressure and heat), it is hard to see how they will make a useful addition to the 49 circular economy in the Global South in the near future. Incineration of waste plastics that have 50 been collected for recycling is comparable with other forms of fossil fuel combustion used to 51 generate energy and, despite the lack of process data, the same is likely for co-processing in 52 cement kilns: notably, neither of these processes can be described as ‘recycling’ and, in general, 53 are deemed as only the last resort in circular cascading systems. Though contemporary air 54 pollution control technology is capable of comprehensively mitigating harmful emissions from 55 combustion, there is a high risk that costly maintenance and management will not be carried out 56 in the absence of strong regulation and enforcement. Inevitably, increasing circular economy 57 activity will require expansion towards targeting flexible, multi-material and multi-layer 58 products, for which mechanical recycling has well-established limitations; which has prompted 59 exploration of alternative approaches. Yet, our comparative risk overview indicates major 60 barriers to changing resource recovery mode from the already dominant mechanical recycling 61 mode towards other nascent or energetic recovery approaches. 62