Design of a PET Molecular Recycling Plant; A Value-laden Design Analysis of Swiss Waste Management in Advancement of US-based Practices

Single-use plastics are produced at exponential rates each year, and their widespread consumption not only implies that the technology will continually be used but also that its implications should be more carefully considered. Because plastics like polyethylene terephthalate (PET) are highly versatile and designed for temporary usage, spent products are often fed to landfills while their micro- and nano-plastic derivatives continually permeate our immune systems and environments. That said, the plastic production process itself is highly intensive, releasing greenhouse gas emissions that further pollute the environment, necessitating more sustainable, circular plastic recycling strategies. Technically, exploring chemical recycling alternatives to traditional incineration and mechanical recycling can create a more robust, long-lasting final PET products, taking in post-consumer plastic waste and regenerating virgin PET pellets for re-use. Moreover, nations like Switzerland stand out as leaders in waste recovery, and applying a value-laden design perspective can elucidate how the Swiss leverage cultural values to create a shared culture of responsibility and environmental stewardship. Combining this analysis of societal values reflected in Swiss waste management policy with a technical study evaluating how to repurpose PET plastic, scholars can develop more effective industry solutions to reduce pollution in the US and beyond. PET is a widely used plastic, often employed in the food and beverage industry as an effective barrier to carbon dioxide and oxygen. Although, as PET is exponentially produced and consumed, circular recycling methods are critical to repurposing spent plastic. Chemical or molecular recycling serves as a viable alternative to landfilling and mechanical recycling that either dispose of or produce plastic that lacks mechanical integrity. Our plant design proposes a methanolysis-based molecular recycling scheme that employs methanol and a potassium carbonate catalyst to depolymerize PET into its monomers dimethyl terephthalate (DMT) and ethylene glycol (EG). Transesterification reactions react the monomers in the presence of a zinc acetate catalyst to form a 1-(2-hydroxyethyl) 4-methyl terephthalate (MHET) intermediate before EG and MHET react once more to create bis (2-hydroxyethyl) terephthalate (BHET). Then, BHET, catalyzed by antimony trioxide, reacts with itself repeatedly in a polycondensation reaction to yield a virgin PET product with increased molecular weight and bottle-grade intrinsic viscosity. Ultimately, this process takes post-consumer PET bales and repurposes them into a bottle-grade product with identical chemical makeup as PET derived from raw materials. In future, we recommend further study of the cosolvent in the depolymerization reaction and redesign of the activated carbon filters. Switzerland is long heralded for its near-total waste recovery system, and its effective implementation of waste management programming raises the question of how cultural values shape the deployment of successful environmental infrastructure. Such analysis can further elucidate lessons for improving recycling systems in the United States (US). This research reveals that Switzerland’s successful waste recovery can be attributed not only to advanced technology and strict policy but also to a value-laden design framework that embeds civic responsibility, accountability, and environmental stewardship into everyday life. Policy analyses, cultural studies, and primary accounts exhibit how technical artifacts like the Polluter Pays Principle and the national garbage tax translate government-level orders into citizen-compliant behavior. In the same vein, government legislation and ethnographic observations show that Swiss citizens perceive waste compliance as both a civic duty and a means of assimilating to society as enforced by societal norms and governance structures. Unfortunately, coalitional gridlock and reliance on incineration as a form of waste recovery limit Switzerland’s waste recycling efforts and its progress toward circularity. This paper concludes that effective waste management systems align technical design and deeply rooted societal values, suggesting that the US should develop shared norms of responsibility and participation while simultaneously enforcing policy reforms.