Sustainable reverse logistics network design for household plastic waste

Plastic recycling is a legal requirement and can yield environmental benefits. In the Netherlands, there is a complex network of various collection methods, separation centers, sorting centers and reprocessors. The first step of the recycling system, separating plastics from other waste, can occur within households (source-separation) or in separation centers (post-separation), making a difference in collection channel choice and technology requirements. The purpose of this paper is to provide decision support on choosing the most suitable combination of separation methods in the Netherlands. Decision support is given through optimized reverse logistics network design which makes the overall recycling system more efficient and sustainable, while taking into account the interests of various stakeholders (municipalities, households, etc.). A mixed integer linear programming (MILP) model, which minimizes both transportation cost and environmental impact, is used in this network design. The research follows the approach of scenario study; the baseline scenario is the current situation and other scenarios are designed with various strategic alternatives. Modeling is conducted by using a graphical optimization tool IBM LogicNet Plus 7.1. Comparing these scenarios, the results show that the current network settings of the baseline situation is efficient in logistics terms but has a potential to adapt to strategic changes, depending on the assumptions regarding availability of the required processing facilities to treat plastic waste. In some of the tested scenarios, a separate collection channel for Polyethylene Terephthalate (PET) bottles is cost efficient and saves carbon emission. Although the figures differ depending on the separation method choices of municipalities, our modeling result of all the tested scenarios shows a saving of more than 25 % carbon emission compared to the current network