In today's world, the concept of a circular economy has emerged as a vital solution to address pressing environmental concerns and foster sustainable development. At its core, the circular economy aims to minimize waste generation by keeping resources in use for as long as possible, thereby reducing the strain on natural ecosystems and promoting resource efficiency. Operations research and data science play a crucial role in implementing circular economy principles by bridging the gap between data generated from new technologies and decision-making processes. This book serves as a comprehensive guide, illustrating how operations research and data science techniques can function as a decision support system, facilitating the optimal implementation of circular economy principles. With a particular focus on waste management, the book delves into various aspects such as recycling, reusing, and refurbishing, providing practical real-world applications and examples. By blending theoretical frameworks with practical insights, the book empowers both professionals and researchers with the essential tools and knowledge to navigate the intricacies of sustainable waste management. It underscores the significance of operations research and data science in facilitating the optimal implementation of circular economy principles. Offering comprehensive insights and actionable examples, readers acquire valuable guidance for implementing positive changes in waste management practices.