Environmental optimization model for a milk collection problem with heterogeneous fleet

Pollution and global warming are current issues of concern, and their mitigation is a challenging problem. Trans-portation and the livestock industry are large generators of Greenhouse Gases (GHG), and therefore environmental criteria must be considered in the decision-making. This paper, part of an ongoing research on the design of milk and dairy supply chains with environmental considerations, proposes a mixed integer programming model for the milk collection problem with heterogeneous fleet with CO2minimization criterion. Validation of the model was made using the Gurobi solver over 15 randomly generated instances, optimally solved, and compared to a distance minimization model. The results show the prevalent use of the largest and most polluting vehicles, in particular, to cover routes with a greater number of farms far from the factory. Also, results suggest that the distance of routes can increase by up to 70% if emissions are optimized, and emissions can increase by up to 20% if distances are minimized. Finally, future research work is proposed.