Designing an optimised supply network for sustainable conversion of waste agricultural plastics into higher value products

Agricultural plastics are currently characterised by a predominantly linear take-make-dispose value chain, thus being a major stream of waste that contributes to significant environmental and economic issues. Therefore, policy makers have recently indicated the adoption of circular economy approaches as the way forward for plastics. This study addresses the problem of agricultural plastic waste as a major stream of landfilled waste by assessing the potential for recycling the plastic into higher value products through pyrolysis and by optimally designing the respective supply network to support this process. A Mixed Integer Linear Programming (MILP) model is developed to optimise the end-to-end supply network design, from the waste generation stage up to the end consumer of the produced material. The model is supported by experimental results on the pyrolysis performance for contaminated plastic samples. The model is applied in a case study of the Scottish agricultural sector to showcase its potential in assessing the feasibility and financial viability in addition to the positive environmental impact on agricultural plastic waste supply networks. The results demonstrate the potential of using the pyrolysis technology for agricultural plastic waste recycling as an example of a circular economy approach and the benefits of using the developed model for decision making purposes, as well as the potential for waste reduction and the implications for farmers' operations.