Environmental and economic take-back planning for plastics from end-of-life computers

Increasing social and regulatory pressures in developed economies are driving the formation of large-scale product take-back systems for end-of-life (EOL) computers. As take-back initiatives move forward, it is becoming increasingly important to identify environmentally and economically sound take-back strategies for plastics, which are ubiquitous in enclosure components and represent a significant fraction of the total materials mass contained in EOL computer equipment. This dissertation develops a systems characterization framework and decision-support tool that facilitate detailed environmental and economic tradeoff analyses of different take-back system scenarios for plastic components to aid in EOL computer take-back planning efforts. The systems characterization framework is based on a structured and comprehensive unit process modeling approach that characterizes the energy consumption, air emissions, solid waste generation, material state transformation, and processing costs of the discrete process steps in a plastics take-back system design space. Direct and overhead costs and environmental impacts are characterized for each unit process, which facilitates take-back system tradeoff and improvements analyses at both the process and facility level. Product design attributes are modeled as independent variables in the systems characterization framework to quantify the critical linkage between detailed design features and take-back system environmental and economic performance. This framework is implemented in a user-friendly decision-support tool to allow electronics recyclers, electronics manufacturers, and policy makers to evaluate the economic and environmental tradeoffs of different processing plans, logistics strategies, and disposition paths for different EOL product designs and therefore adds powerful "scenario-playing" capabilities to take-back planning efforts for all major stakeholders. The utility of this research in real-world decision-making processes is illustrated through two example applications, which demonstrate how electronics recyclers can use the decision-support tool to choose appropriate plastics take-back strategies for different product designs based on available processing and disposition options and how electronics manufacturers can use the decision-support tool to support proactive "design for take-back" initiatives for plastic components in new computer products.