Selection Supplier with Considering Environmental Factors

New requirements and developments in the world of business and commerce era provide a background to the emergence of new attitudes which is essential for those involved in the field of production and trade. In this regard, there are new approaches and attitudes on the issue of supply chain which environmental requirements will lead to the green one. In this study, in addition to the suppliers directly associated with the company, suppliers that provide raw materials for manufacturers also considered in the second layer of supply and optimal suppliers are selected from both layers. This paper presents an interesting idea, proposing a multi-product model to solve the multiple sourcing green suppliers' problems. Goals of our model are maximizing the value of suppliers and minimizing the costs due to environmental pollution, the cost of purchasing, the fixed ordering cost, transportation costs and penalties for the returned goods.