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