As an important approach to recover solid waste, the recycling of waste polyester has drawn a growing level of public concern. This study aims to investigate the life cycle assessment and social cost of life cycle assessment of waste polyester recycling. The results show that the polyester recycling process itself has significant environmental impact on global warming, fossil resource scarcity, human carcinogenic toxicity, water consumption and terrestrial ecotoxicity. Global warming, terrestrial ecotoxicity and land use are the most influential categories of social cost of life cycle assessment, with a contribution of 55.7%, 10.9% and 6.3% respectively. Through key process identification, sensitivity analysis and integrated evaluation study, it is found that electricity generation, direct air emissions and transportation are key processes that affect social cost of life cycle assessment and life cycle assessment. The effects of these key processes on social cost of life cycle assessment are greater than that on life cycle assessment. Consequently, the corresponding optimization measures are proposed in order to improve the sustainability performance of polyester industry.

Introduction

With the rapid urbanization, polyester (PET) has become an indispensable part of social life (Debrot et al., 2013). In 2015, the global output of plastic products reached 269 million tons, 3.3% higher than that in 2014. In 2017, China’s plastic products output reached 75.155 million tons, with an annual growth rate of 3.4% on average (Liu, 2018). Since waste PET cannot be degraded by itself, the traditional treatment approach such as direct landfill will cause serious environmental pollution and resource waste (Raqueline et al., 2018). Therefore, PET recycling has become an important approach to recover solid waste (Handy and Xiu, 2018; Kim et al., 2017). At present, waste PET recycling has gained rapid growth in China through the physical or chemical recycling methods (Lao et al., 2003; Bar any et al., 2007 ). Most recycled PET slices are used to produce short PET fibers (Zhao et al., 2018). However, there is no study to examine the impact of this kind of PET recycling technology on environment and society. The key processes for the environment and willingness to pay (WTP) are evaluated quantitatively from the perspective of life cycle assessment (LCA) in this research. Countermeasures and suggestions are proposed for mitigating its impact on environment and WTP. LCA can quantify the environmental impacts of products from cradle to grave and identify the key processes and key substances (ISO, 2006; Leila et al., 2018). Lopes et al. (2003) applied LCA to the paper industry in Portuguese, the results showed that it was more environmentally friendly to use natural gas instead of fuel oil for production.