Environmental friendly route design for a milk collection problem: the case of an Indian dairy

The green vehicle routing problem advised by the global sustainability conscience is a seminal work on the contemporary green research in supply chain management. Inspired by the replete, pollution routing literature, the present work acknowledges the significance of redesigning the logistic networks in a low emission perspective. The present research proposes three logistic models to address the vehicle routing problem of a dairy plant for collecting milk from chilling centres. The first model generates classical, distance centric and economically viable milk pickup plans. In the second model, the environmental friendly routes are generated. The third model is slated to bring a tradeoff between the first two models. The three models are formulated as integer linear programming models and are solved with branch-and-bound based exact algorithm. Owing to the complexity of the NP-hard problem for generating time-bound results, an ant colony optimisation algorithm is designed to solve the models. The performance of the algorithm is further enhanced by introducing a powerful variable neighbourhood search. The computational study on hybrid algorithm reports an average 0.25% improvement from a time interrupted solution of the exact algorithm. The study recommends decisive managerial insights for implementing green principles to the dairy industry.