Regional optimization model for locating supplemental recycling depots.

In Taiwan, vendors and businesses that sell products belonging to six classes of recyclable materials are required to provide recycling containers at their local retail stores. The integration of these private sector facilities with the recycling depots established by local authorities has the potential to significantly improve residential access to the recycling process. An optimization model is accordingly developed in this work to assist local authorities with the identification of regions that require additional recycling depots for better access and integration with private facilities. Spatial accessibility, population loading and integration efficiency indicators are applied to evaluate whether or not a geographic region is in need of new recycling depots. The program developed here uses a novel algorithm to obtain the optimal solution by a complete enumeration of all cells making up the study area. A case study of a region in Central Taiwan is presented to demonstrate the use of the proposed model and the three indicators. The case study identifies regions without recycling points, prioritizes them based on population density, and considers the option of establishing recycling centers that are able to collect multiple classes of recycling materials. The model is able to generate information suitable for the consideration of decision-makers charged with prioritizing the installation of new recycling facilities.