Hydrothermal Treatment of Waste Plastics: An Environmental Impact Study

Abstract

This paper presents the attributional life cycle assessment results of a study of plastic recycling using hydrothermal treatment (HTT), a chemical recycling technology. HTT was investigated due to its potential to address current gaps in the plastic recycling system, largely due to several plastic packaging materials and formats that are currently not processed by traditional mechanical recycling technologies. As society transitions towards a net-zero-based circular economy, assessments should be conducted with a futuristic outlook, preventing costly mistakes by employing the right technologies in the right areas. The results using ReCiPe 2016 impact assessment methodology shows HTT with a GWP of 478 kg CO2 eq. per tonne can generate up to 80% reduction in climate change impacts when compared with comparable end-of-life treatment technologies whilst conserving material with the system. Additionally, the GWP could be reduced by up to 57% by changing how electricity is generated for on-site consumption. This represents a new understanding of the chemical recycling of polymers by establishing a prospective life cycle assessment study that looks to introduce a step-change in the recycling system and highlights the benefits of introducing this technology as opposed to the current model of disposal through incineration or landfill.